Title of Invention	POWER UNIT MOUNTED ON VEHICLE
Abstract	A power unit (P) mounted on a vehicle comprising an internal combustion engine (E), a speed change gear (70) comprising a speed change portion (70a) to which power of a crank shaft (20) of said internal combustion engine (E) is transmitted and an output portion (70b) for outputting the, power speed-changed by said speed change portion (70a), a final speed reduction device (R2) to which the power of said output portion (70b) is transmitted through an intermediate speed reduction device (R1), and a transmission case (c), containing said speed change gear, the power from said final speed reduction device (R2) being transmitted to a driving shaft, characterized in that said intermediate speed reduction device (Rl) and said final speed reduction (R2) device are contained in said transmission case (c), said speed change portion (70a) is disposed on the side of said internal combustion engine (E), whereas said output portion (70b) is disposed on the side opposite to said internal combustion engine with respect to said driving shaft, and said speed change gear (70) is disposed on the upper side of said intermediate speed reduction device (Rl) disposed on the upper side of said final speed reduction device (R2); and the power unit P is swingable about the axis in the right-left direction of the left and right bushes (12) with respect to main frame.

Title of Invention

POWER UNIT MOUNTED ON VEHICLE

Abstract

A power unit (P) mounted on a vehicle comprising an internal combustion engine (E), a speed change gear (70) comprising a speed change portion (70a) to which power of a crank shaft (20) of said internal combustion engine (E) is transmitted and an output portion (70b) for outputting the, power speed-changed by said speed change portion (70a), a final speed reduction device (R2) to which the power of said output portion (70b) is transmitted through an intermediate speed reduction device (R1), and a transmission case (c), containing said speed change gear, the power from said final speed reduction device (R2) being transmitted to a driving shaft, characterized in that said intermediate speed reduction device (Rl) and said final speed reduction (R2) device are contained in said transmission case (c), said speed change portion (70a) is disposed on the side of said internal combustion engine (E), whereas said output portion (70b) is disposed on the side opposite to said internal combustion engine with respect to said driving shaft, and said speed change gear (70) is disposed on the upper side of said intermediate speed reduction device (Rl) disposed on the upper side of said final speed reduction device (R2); and the power unit P is swingable about the axis in the right-left direction of the left and right bushes (12) with respect to main frame.

Full Text	FORM 2 THE PATENTS ACT 1970 [39 OF 1970] PROVISIONAL/COMPLETE SPECIFICATION [See Section 10] "POWER UNIT MOUNTED ON VEHICLE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-kU, Tokyo, Japan The following specification particularly describes the nature of the invention and the manner in which it is to be performed :- Granted 31-5-2006 18 JUL 2001 [Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to a power unit mounted on a vehicle and transmitting the power of an internal combustion engine to a driving shaft through a clutch, a speed change gear and a speed reduction device, and more particularly to a layout structure of the internal combustion engine, the clutch, the speed change gear and the speed reduction device constituting the power unit. [0002]- [Prior Art] Hithterto, as a device of this type, there has been known the driving device of a four-wheel motor vehicle disclosed in Japanese Utility Model Open No. Hei 4-28116. The driving device comprises an engine with a crank shaft disposed longitudinally with respect to the vehicle body, a first input shaft operated in conjunction with the crank shaft through a speed reduction gear and a clutch, a transmission comprising a speed change mechanism, a second input shaft to the speed change mechanism and an output shaft from the speed change mechanism, and a pair of gears for operating the first input shaft and the second input shaft in conjunction with each other. The second input shaft, the speed change mechanism and the output shaft constituting the transmission are disposed in a gear case, and the output shaft and a rear wheel driving shaft are operated in conjunction with each other through a bevel gear constituting a final speed reduction device. [Problem to Be Solved by the Invention] According to the prior art as above, the speed change mechanism connected to the second input shaft extending rearward from the engine disposed on the front side of the rear wheel driving shaft is disposed on the rear side of the rear wheel driving shaft, so that the masses of the driving device including the engine are not concentrated in the longitudinal direction, and there is room for improvement in drivability. In addition, the gear case is inevitably enlarged, and the driving device constituted of the engine and the transmission is • inevitably enlarged, so that the degree of freedom in layout of the members disposed in the periphery of the driving device is restricted, and the vehicle body is enlarged in size in the longitudinal direction. Besides, since the output shaft is coaxial with the input shaft of the final speed reduction device, the speed change mechanism having a relatively large diameter is disposed in the vicinity of the rear wheel driving shaft in the upper-lower direction, so that there is the drawback that the minimum height from the ground of the vehicle is lowered. The present invention has been made in consideration of the above-mentioned situations, and, accordingly, it is an object of the present invention to contrive mass concentration and compact design in a power unit mounted on a vehicle and to prevent the minimum height from the ground of the vehicle from being lowered. [Means for Solving the Problem and Effects of the Invention] The invention as set forth in claim 1 of the present application resides in a power unit mounted on a vehicle comprising an internal combustion engine, a speed change gear comprising a speed change portion to which power of a crank shaft of the internal combustion engine is transmitted and an output portion for outputting the power speed-changed by the speed change portion, a final speed reduction device to which the power of the output portion is transmitted through an intermediate speed reduction device, and a transmission case containing the speed change gear, the power from the final speed reduction device being transmitted to a driving shaft, wherein the intermediate speed reduction device and the final speed reduction device are contained in the transmission case, the speed change portion is disposed on the side of the internal combustion engine whereas the output portion is disposed on the side opposite to the internal combustion engine with respect to the driving shaft, and the speed change gear is disposed on the upper side of the intermediate speed reduction device disposed on the upper side of the final speed reduction device. According to the invention as set forth in claim 1, the speed change portion of the speed change gear is disposed on the side of the internal combustion engine with respect to the driving shaft, so that the speed change portion occupying a large weight in the speed change gear is disposed relatively close to the internal combustion engine large in weight, and concentration of masses in the power unit mounted on the vehicle is accomplished. In addition, since the intermediate speed reduction device and the final speed reduction device are in an upper-and-lower positional relationship, both the speed reduction devices are disposed side by side in the longitudinal direction, and, since the speed change portion is disposed on the side of the internal combustion engine while the output portion is disposed on the side opposite to the internal combustion engine with respect to the driving shaft, the distance between the output portion and the driving shaft can be reduced, so that the transmission case containing the speed change gear, the intermediate speed reduction device and the final speed reduction device can be made compact. Furthermore, in the power unit, the speed change gear is disposed on the upper side of the intermediate speed reduction device located on the upper side of the final speed reduction device, so that the speed change gear is located relatively away from the driving shaft in the vertical direction, and, therefore, the minimum height from the ground of the vehicle is prevented from being lowered due to the speed change gear. As a result, in the power unit, mass concentration is achieved, and drivability of the vehicle is enhanced. In addition, since the transmission case can be made compact, the power unit is made compact, and the degree of freedom in laying out the members disposed in the periphery of the power unit is increased. Furthermore, the minimum height from the ground of the vehicle is prevented from being lowered due to the layout of the speed change gear of the power unit. The invention as set forth in claim 2 resides in a power unit mounted on a vehicle as set forth in claim 1, wherein the speed change gear comprises a speed change gear shaft for transmitting power to the speed change portion by being drive - connected to the crank shaft through a clutch having a clutch shaft disposed on the upper side of the crank shaft, the clutch shaft is coaxial with the speed change gear shaft, and the clutch is disposed side by side with the crank shaft in the l'ongitudinal direction. According to the invention as set forth in claim 2, in addition to the effects of the invention as set forth in claim 1, the clutch shaft and the speed change gear shaft are coaxial with each other, so that the crank shaft is located nearer to the driving shaft than the clutch and the speed change gear and, therefore, the center of gravity of the vehicle can be lowered. In addition, since the clutch shaft and the speed change gear shaft are coaxial with each other and the clutch having the clutch shaft is disposed side by side with the crank shaft in the longitudinal direction, the speed change gear can be located near to the internal combustion engine in the longitudinal direction, which also ensures that concentration of masses in the longitudinal direction can be achieved in the power unit, and the power unit is made compact in the longitudinal direction. As a result, of the effects of the invention as set forth in claim 1, the concentration of masses and compact design in the power unit can be further promoted, and the center of gravity of the vehicle can be lowered, whereby running stability is enhanced. The invention as set forth in claim 3 resides in a power unit mounted on a vehicle as set forth in claim 2, wherein the crank shaft is disposed directed in the longitudinal direction, a cylinder of the internal combustion engine having a substantially horizontal center axis is disposed on one lateral side in the right-left direction with respect to the crank shaft, and the clutch, the speed change gear and the intermediate speed reduction device having rotational axes parallel to the rotational axis of the crank shaft are disposed on the other lateral side in the right-left direction with respect to the crank shaft. According to the invention as set forth in claim 3, in addition to the effects of the invention as set forth in claim 2, since the clutch, the speed change gear and the intermediate speed reduction device having rotational axes parallel to the rotational axis of the crank shaft are disposed on the side opposite to the side where the cylinder occupying a large space is disposed with respect to the crank shaft, the component elements of the power unit can be laid out in a compact configuration in the periphery of the rotational axis of the crank shaft, and accessory parts (for example, an air cleaner) of the internal combustion engine and parts to be fitted to the vehicle body can be disposed in a space formed at the direct rear of the cylinder on the side where the cylinder is disposed. In addition, since the center axis of the cylinder is substantially horizontal, the center of gravity of the internal combustion engine can be lowered, and, hence, the center of gravity of the vehicle can be lowered. As a result, of the effects of the invention as set forth in claim 2, the lowering of the center of gravity of the vehicle can be further promoted, the component elements of the power unit can be laid out in a compact configuration in the periphery of the rotational axis of the crank shaft, the power unit can be made compact with the rotational axis of the crank shaft as a center, and parts can be laid out by utilizing the space formed at the direct rear of the cylinder, whereby the vehicle body can be made compact. The terms "upper", "lower", "front", "rear", "left" and "right" used herein mean the "upper", "lower", "font", "rear", "left" and "right" with respect to the vehicle body. [Mode for Carrying Out the Invention] Now, an embodiment of the present invention will be described below referring to Figs. 1 to 4. According to the present invention there is provided a power unit mounted on a vehicle comprising an internal combustion engine, a speed change gear comprising a speed change portion to which power of a crank shaft of said internal combustion engine is transmitted and an output portion for outputting the power speed-changed by said speed change portion, a final speed reduction device to which the power of said output portion is transmitted through an intermediate speed reduction device, and a transmission case, containing said speed change gear, the power from said final speed reduction device being transmitted to a driving shaft, characterized in that said intermediate speed reduction device and said final speed reduction device are contained in said transmission case, said speed change portion is disposed on the side of said internal combustion engine, whereas said output portion is disposed on the side opposite to said internal combustion engine with respect to said driving shaft, and said speed change gear is disposed on the upper side of said intermediate speed reduction device disposed on the upper side of said final speed reduction device; and the power unit P is swingable about the axis in the right-left direction of the left and right bushes with respect to main frame. [BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS] [Fig. 1] Fig. 1 is a left side view of major part showing the positional relationship between a vehicle body frame and a power unit of a motor scooter type motor tricycle on which the power unit of the present invention is mounted. [Fig. 2] Fig. 2 is a rear view of a section passing through the center axis of the cylinder, showing the positional relationships of rotational axes of shafts. [Fig. 3] Fig. 3 is a sectional view taken generally along line III-III of Fig. 2. [Fig. 4] Fig. 4 is a sectional view taken generally along line IV-IV of Fig. 1. Fig. 1 is a left side view of essential portions showing the positional relationship between a vehicle body frame F and a power unit P of a motor scooter type motor tricycle V on which a power unit according to the present invention is mounted. The motor tricycle V comprising a single front wheel Wf which is a driven wheel and a pair of left and right rear wheels Wr which are driving wheels comprises the vehicle body frame F which has a main frame comprising a front frame 1 whose rear portion is branched into left and right portions and a pair of left and right rear frames 2 connected to the rear portions of the front frame 1 by bolts, and a sub-frame 3 . A steering mechanism 4 for steering the front wheel Wf and a front suspension mechanism 6 having a swing arm 5 swingably supported about an axis in the right-left direction at a lower portion of a front portion of the front frame 1 and supporting the front "wheel Wf are * provided at the front portion of the front frame 1. A Neidhart mechanism 7 comprising a cylindrical portion, a shaft portion inserted in the cylindrical portion and a rubber-made elastic body fitted in a radial gap between the cylindrical portion and the shaft portion is fitted to a rear portion of the front frame 1 through a plate 8, and a power unit P for driving the left and right rear wheels Wr is supported on the right-left pair of sub-frames 3 connected to the cylindrical portion of the Neidhart mechanism 7 by bolts. Further, a seat 9 is disposed on the upper side of the rear portion of the front frame 1, and a storage box 10 having an opening portion opened and closed by the seat 9 and storing goods such as a helmet and the like is provided on the lower side of the seat 9. A front portion of the power unit P comprising a water-cooled type internal combustion engine E and a transmission device M is supported on the sub-frames 3 by a pair of hanger bolts respectively inserted through hanger holes of brackets 11 respectively fitted to the sub-frames 3 and a right-left pair of bushes 12 (in Fig. 1, the left bush 12 is shown) provided on the internal combustion engine E. The lower end of a rear portion of the power unit P is supported by a bush (not shown) provided at a right side portion of a transmission case C in which the transmission device M is contained, on the front side of a rear axle 13, and the upper end of the rear portion of the power unit P is supported on the sub-frames 3 through a buffer 14 supported between rear end portions of the sub-frames 3 whose rear portions are bent to be close to each other at a roughly central .position in the right-left direction of the vehicle body. By this arrangement, the power unit P is swingable about the axis in the right-left direction of the left and right bushes 12 and swingable about the axis in the longitudinal direction of the Neidhart mechanism 7, with respect to the main frame. Next, the internal combustion engine E and the transmission device M for transmitting the power of the internal combustion engine E to the rear wheels Wr which constitute the power unit P will be further described, referring to Fig. 2 which is a rear view of a section passing through the center axis L2 of a cylinder 22 for illustrating the positional relationship of rotational axes of shafts. Fig. 3 which is a sectional view taken generally along line III-"III of Fig. 2, and Fig. 4 which is a sectional view taken generally along line IV-IV of Fig. 1. The transmission device M comprises a centrifugal clutch 60, a cone type non-stage transmission 70, an intermediate speed reduction device Rl and a final speed reduction device R2. Of these components, the clutch 60 is contained in a crankcase 21 of the internal combustion engine E, whereas the non-stage transmission 70, the intermediate speed reduction device Rl and the final speed reduction device R2 are contained in the transmission case C. Referring to Figs. 2 and 4, the internal combustion engine E is a single-cylinder 4-cycle internal combustion engine, and a crank shaft 20 is longitudinally disposed with its rotational axis L1 disposed in the longitudinal direction of the vehicle body, and is disposed in a substantially central position in the right-left direction of the vehicle body. A cylinder 22 having a center axis L2 substantially horizontal to the rotational axis L1 of the crank shaft 20, namely, extending to the right or to a slantly right upper side in the range of 0 to 20 , in this embodiment extending to a slightly slantly right upper side is disposed on the right side of the crank shaft 20, whereas the clutch 60, the non-stage transmission 70, the intermediate speed reduction device Rl and the final speed reduction device R2 are disposed on the left side of the crank shaft 20. Further, a clutch shaft 61 of the clutch 60 and a transmission shaft 71 of the non-stage transmission 70 are coaxial with each other, and their rotational axes L3, L4 are parallel to the rotational axis L1, and are disposed on the slantly left upper side at an angle larger than the center axis of the cylinder 22 from the horizontal direction with respect to the rotational axis L2 A crankcase 21 of the internal combustion engine. E is split at a plane containing the rotational axis L2 and being ar.thogtonal to the center axis L2 of the cylinder 22, into a. right; crankcase 21R formed integrally with the cylindex." 2:2 by casting and a left crankcase 21L. containing the clutch 6 0 therein. A cylinder. head. 2:3; and a cylinder head cover 24 are sequentially mounted on: the cylinder 22. A piston 25 slidably fitted in the. cyiinder 22 and reciprocated is connected to the crank shaft. 2.0: through a connecting rod 26,. whereby the crank, shaft; 2:0; is driven to rotate The cylinder head 23 is: provided:, with.an intake passage 28" opened into a combustion chamber:27, an exhaust passage. 2 9. and a supercharging passage: 30, and is fitted, with, an ignition.-, plug 3:1, for. igniting a mixture gas: of a: fuel inje;cted;.:£rcair;:.a-£u.ei., ignition valve into the intake passage 28 and intake air Further, a compound operation.type piston type supercharger 32 having a reciprocating supercharging, piston 32a is provided on the upper side of the. cylinder 22. The supercharging piston 32a.is driven to reciprocate by driving the supercharging crank shaft drive-connected to the supercharging piston 32a to rotate at the same rotating speed as a cam shaft 43 (described later) through a transmission belt wrapped around the supercharging crank shaft and the cam shaft 43. Referring to Fig. 3, the crank shaft 20 is rotatably supported by crank shaft holders 33, 34 consisting of a pair of plates disposed at a predetermined spacing therebetween in the longitudinal direction and connected to the crankcase 21 and the cylinder 22 by a plurality of bolts fastened in the direction of the rotational axis LI, through ball bearings 35, 36 which are a pair of main bearings. An AC generator 37 is provided at a front end portion of the crank shaft 20 extending more to the front side than ball bearing 35, and a cooling fan 39 for feeding cooling wind to a radiator 38 disposed on the front side of a rotor of the AC generator 37 integrally fixed to the crank shaft 20 is integrally rotatably connected to the rotor. A trochoid type oil pump 40 is provided on the rear side of the crank shaft 20, and a rotor is driven to rotate inside a pump casing fixed to the crankcase 21 by a hollow pump driving shaft 40a consisting of a piping fixed to a rear end portion of the crank shaft 20 extending more to the rear side than the ball bearing 36. An oil sucked from an oil pool at a bottom portion of the crankcase 21 and discharged from the oil pump 40 is supplied to parts to be lubricated of the internal combustion engine E, the clutch 60, the non-stage transmission 70 and the like through an oil passage formed of the hollow portion of the pump driving shaft 40a, then through oil passages provided in the crankcase 21, the cylinder 22 and the cylinder head 23 and through an oil filter 41 (See Fig. 1) fitted to a left side portion of the transmission case C. Referring to Fig. 2, a timing gear 42 connected to a rear end portion of the crank shaft 20 is meshed with a cam gear 44 connected to a cam shaft 43 rotatably -. i f supported on the crank shaft holders 33, 34, and the cam shaft 43 is driven to rotate at a speed reduction ratio of 1/2 relative to the crank shaft 20. Intake, exhaust and supercharging cams provided on the cam shaft 43 respectively swing intake, exhaust and supercharging cam followers constituting a cam follower group 46 swingably supported on a support shaft 45 supported by the crank shaft holders 33, 34. The motions of the cam followers respectively swing intake, exhaust and supercharging rocker arms constituting a rocker arm group 49 swingably supported on a rocker arm shaft 48 provided at the cylinder head 23 through intake, exhaust and supercharging pull rods constituting a pull rod group 47, and an intake valve 50, an exhaust valve 51 and a supercharging valve 52 respectively in contact with the rocker arms open and close opening portions of an intake passage 28, an exhaust passage 29 and a supercharging passage 30 on the side of the combustion chamber 27 at predetermined timings. A driving gear 53 provided on the outer periphery of a rear portion crank web of the crank shaft 20 is meshed with a driven gear 62 rotatably fitted to the clutch shaft 61 and rotated at the same rotating speed with the driving gear 53, and the power of the crank shaft 20 is transmitted to a transmission shaft 71 of the non-stage transmission 70 spline-connected to the clutch shaft 61 rotatably supported on the crank shaft holder 33, 34 through a pair of ball bearings 63, 64 respectively mounted on the crank shaft holders 33, 34. Thus, the clutch 60 is disposed between the crank shaft holders 33 and 34, and, therefore, the clutch 60 and the clutch shaft 61 are disposed in side-by-side relation in the longitudinal direction with the crank shaft 20 which is disposed on the slantly right lower side of them. The clutch 60 as a starting clutch comprises a bowl - shaped clutch outer 60a integrally rotatably connected to the clutch shaft 61, and a drive plate 60b disposed on the inside of the clutch outer 60a, drive-connected to the driven gear 62 and rotatably fitted to the clutch shaft 61. When the driven gear 62 is rotated at a rotating speed higher than a predetermined rotating speed of the internal combustion engine E, a plurality of clutch shoes 60c swingably supported on the drive plate 60b are swung radially outwards by centrifugal forces against the springy force of a clutch spring 60d, and friction members provided at outer peripheral surfaces of the clutch shoes 60c come into contact with the inner peripheral surface of the clutch outer 60a, whereby the clutch 60 comes into a connected condition, and the rotation of the driven gear 62 is transmitted to the clutch shaft 61. The transmission shaft 71 to which the power of the clutch shaft 61 is transmitted has its front end portion rotatably supported on the crank shaft holders 33, 34 at a portion of spline connection with the clutch shaft 61 together with a rear end portion of the clutch shaft 61 on the outer peripheral side thereof through a ball bearing 64, and has its rear end portion rotatably supported on the transmission case C through a ball bearing 72. The non-stage transmission 70 comprises a speed change portion 70a for changing the rotating speed of the transmission shaft 71, and an output portion 70b for outputting the power at the rotating speed changed by the speed change portion 70a. The speed change portion 70a is disposed on the side of the internal combustion engine E which is the front side with respect to the rear axle 13 as a driving shaft in the longitudinal direction, whereas the output portion 70b is disposed on the opposite side of the internal combustion engine E which is the rear side with respect to the rear axle 13, namely, on the side opposite to the side of the internal combustion engine E with respect to the rear axle 13 in the longitudinal direction. A trochoid type oil pump 73 is provided at a portion of the transmission shaft 71 on the rear side of the ball bearing 72, and an oil sucked through an oil filter 74 is supplied to the speed change portion 70a and the like through an oil passage provided in the inside of the transmission shaft 71. The speed change portion 70a comprises a cone holder 76 holding a plurality of cones 75 arranged in a ring form around the transmission shaft 71 and being movable in the direction of the rotational axis L4 of the transmission shaft 71, a driving face 77 integrally rotatably connected to the transmission shaft 71 and having an outer peripheral surface in contact with each of the cones 75, a driven face 78 rotatably supported on the transmission shaft 71 through a roller bearing 79 and having an inner peripheral surface in contact with each of the cones 75, and an electric motor 80 (See Figs. 1 and 4) for moving the cone holder 76 in the direction of the rotational axis L4. The output portion 70b comprises an output gear 82 rotatably supported on the transmission shaft 71 through a ball bearing 81 and integrally rotatably connected to the driven face 78. The non-stage transmission 70 is provided with an input rotating speed sensor and an output rotating speed sensor which are not shown; based on rotating speeds detected by the sensors, the rotation of the electric motor 80 is controlled by an electronic control device so as to obtain a speed change ratio set according to throttle valve opening and rotating speed which show the operating conditions of the internal combustion engine E, whereby the cone holder 76 is moved in the direction of the rotational axis L4 . The output gear 82 located on the rear side of the rear axle 13 is meshed with a first intermediate input gear 86 provided at a front portion of an intermediate shaft 85 disposed on the lower side of the transmission shaft 71 and rotatably supported on the transmission case C through a pair of ball bearings 83, 84. A first intermediate output gear 87 is provided at a rear portion of the intermediate shaft 85, and the first intermediate output gear 87 is meshed with a second intermediate input gear 88 which is integrally rotatably connected to a rear portion of a pinion shaft 89 provided with a pinion gear 90 constituting the final speed reduction device R2 together with a ring gear 91 (See Fig. 4) and which is constituted of a gear larger in diameter than the first intermediate output gear 87. A front portion of the pinion shaft 89 is rotatably supported on a speed reduction case portion 92 provided as a portion of the transmission case C through a ball bearing 93, and a rear portion of the pinion shaft 89 is rotatably supported on the transmission case C through a ball bearing 94. Therefore, the first intermediate input gear 86, the first intermediate output gear 87 and the second intermediate input gear 88 constitute the intermediate speed reduction device R1 which transmits the power from the output portion 70b of the non-stage transmission 70 to the pinion shaft 89 by reducing the rotating speed. As shown in Fig. 4, the pinion gear 90 is meshed with the ring gear 91 spline-connected to a differential case 95 contained in the speed reduction case portion 92, and final speed reduction of the rotating speed of the crank shaft 20 is conducted. A left axle pipe 96L containing a left rear axle 13L therein and a right axle pipe 96R containing a right rear axle 13R therein are respectively connected by bolts to a left opening portion and a right opening portion of the speed reduction case portion 92. A differential device D comprises the differential case 95, a pinion shaft 97 fixed by penetrating through the inside of the differential case 95, a pair of pinion gears 98, 99 fixed to both ends of the pinion shaft 97, and a right-left pair of side gears 100, 101 meshed with the pinion gears 98, 99. The left rear axle 13L and the right rear axle 13R are spline - connected to the left and right side gears 100, 101, respectively. By such constitution of the transmission device M, the power of the crank shaft 20 is transmitted to the clutch 60 through the driven gear 62 meshed with the driving gear 53, and the power of the clutch shaft 61 of the clutch 60 is transmitted to the speed change portion 70a through the transmission shaft 71 of the non-stage transmission 70. Speed change is carried out in the speed change portion 70a so as to obtain a speed change ratio set according to the operating conditions of the internal combustion engine E, and the power thus speed-changed is transmitted from the output gear 82 to the final speed reduction device R2 through the intermediate speed reduction device Rl, and then through the differential device D to the left and right rear axles 13, whereby the rear wheels Wr are driven. Here, referring to Fig. 2, the layout of the crank shaft 20, the clutch shaft 61, the transmission shaft 71, the intermediate shaft 85 and the pinion shaft 89 for transmitting the power of the crank shaft 20 to the rear axles 13 will be described. The rotational axis L5 of the intermediate shaft 85 parallel to the rotational axis L1 of the crank shaft 20 is located on a slightly slantly left upper side of the rotational axis L1 of the crank shaft L1 and is located lower than the rotational axis L4 of the transmission shaft 71 and closer to the rotational axis L1. The rotational axis L6 of the pinion shaft 89 parallel to the rotational axis L1 of the crank shaft 20 is located on a slightly slantly left lower side of the rotational axis L1 of the crank shaft 20 and is located lower than the rotational axis L5 of the intermediate shaft 85 and closer to the rotational axis L1. Therefore, the transmission shaft 71, the intermediate shaft 85 and the pinion shaft 89 are located more closer to the rotational axis L1 of the crank shaft 20 in this order. By this layout, masses can be concentrated in the right-left direction in the power unit P, and the transmission case C can be made compact. Next, the effects of the embodiment constituted as described above will be described. Since the speed change portion 70a of the non-stage transmission 70 is disposed on the side of the internal combustion engine E with respect to the rear axles 13, the speed change portion 70a occupying a large weight in the non-stage transmission 70 is located comparatively close to the internal combustion engine E having a large weight, so that mass concentration is achieved in the power unit P mounted on the motor tricycle V which is a vehicle. In addition, since the intermediate speed reduction device Rl and the final speed reduction device R2 are in an upper-lower positional relationship, both the speed reduction devices Rl, R2 are disposed side by side in the longitudinal direction. Further, since the speed change portion 70a is disposed on the side of the internal combustion engine E while the output portion 70b is disposed on the opposite side of the internal combustion engine E with respect to the rear axles 13, the distance between the output gear 82 and the rear axles 13 in the longitudinal direction can be reduced, so that the transmission case C containing the non-stage transmission 70, the intermediate speed reduction device Rl and the final speed reduction device R2 can be made compact in the longitudinal direction. Furthermore, since the non-stage transmission 70 is disposed on the upper side of the intermediate speed reduction device Rl located on the upper side of the final speed reduction device R2 in the power unit P, the non-stage transmission 70 is located comparatively away from the rear axles 13 in the vertical direction, so that the minimum height from the ground of the vehicle can be prevented from being lowered due to the transmission. As a result, mass concentration is achieved in the power unit P, and the drivability of the motor tricycle V is enhanced. In addition, since the transmission case C can be made compact in the longitudinal direction, the power unit P is made compact in the longitudinal direction, and the degree of freedom in layout of the members disposed in the periphery of the power unit P is increased. Further, the minimum height from the ground of the motor tricycle V is prevented from being lowered due to the layout of the non-stage transmission 70 of the power unit P. Since the crank shaft 20 is located nearer to the rear axles 13 than the clutch 60 and the non-stage transmission 70 having the clutch shaft 61 and the transmission shaft 71 coaxial with each other, the center of gravity of the motor tricycle V can be lowered. In addition, since the clutch shaft 61 and the transmission shaft 71 are coaxial with each other and the clutch 60 having the clutch shaft 61 is disposed side by side with the crank shaft 20 in the longitudinal direction, the non-stage transmission 70 can be disposed close to the internal combustion engine E in the longitudinal direction, and, in this point, also, masses can be concentrated in the longitudinal direction in the power unit P, which is made compact in the longitudinal direction. As a result, the mass concentration and compact designing of the power unit P can be further promoted, and the center of gravity of the motor tricycle V can be lowered, which ensures enhanced running stability. Since the cylinder 22 occupying a large space is disposed on the right side of the crank shaft 20 while the clutch 60, the non-stage transmission 70, the intermediate shaft 85 and the pinion shaft 89 respectively having the rotational axes L3, L4, L5 and L6 parallel to the rotational axis L1 of the crank shaft 20 are disposed on the right side of the crank shaft 20, these component elements of the power unit P can be disposed in a compact configuration in the periphery of the rotational axis L1 of the crank shaft 20, and accessory parts (for example, air cleaner) of the internal combustion engine E and parts to be fitted to the vehicle body can be disposed in the space formed at the direct rear of the cylinder 22 on the side where the cylinder 22 is disposed. Besides, since the center axis L2 of the cylinder 22 is substantially horizontal, the center of gravity of the internal combustion engine E can be lowered, and, hence, the center of gravity of the motor tricycle V can be lowered. As a result, the lowering of the center of gravity of the motor tricycle V can be promoted, and the clutch 60, the non-stage transmission 70, the intermediate shaft 85 and the pinion shaft 89 which are component elements of the power unit P are disposed in a compact configuration in the periphery of the rotational axis L1 of the crank shaft 20, so that the power unit P can be made compact with the rotational axis L1 as a center, and parts can be disposed utilizing the space formed at the direct rear of the cylinder 22, whereby the vehicle body can be made compact. Further, since the transmission shaft 71, the intermediate shaft 85 and the pinion shaft 89 having the rotational axes L4 , L5 and L6 parallel to the rotational axis L1 of the crank shaft 20 occupy positions closer to the rotational axis L1 of the crank shaft 20 in this order, mass concentration in the right-left direction can be achieved in the power unit P, and the transmission case C can be made small in size. As a result, the drivability of the motor tricycle V is enhanced, and the power unit P is made compact in the longitudinal direction. Now, as to embodiments obtained by modifying part of the constitution of the above-described embodiment, the modified constitution will be described. While the non-stage transmission 70 is of the cone type in the above embodiment, a swash-type non-stage transmission and other single-shaft type transmission may be used. Besides, while the vehicle is a motor tricycle in the above embodiment, the vehicle may be a motorcycle or a four-wheel motor vehicle. [Description of Reference Numerals] 1: front frame; 2: rear frame; 3: sub-frame; 4: steering mechanism; 5: swing arm; 6: front suspension mechanism; 7: Neidhart mechanism; 8: plate; 9: seat; 10: storage box; 11: bracket; 12: bush; 13: rear axle; 14: buffer; 20: crank shaft; 21: crankcase; 22: cylinder; 23: cylinder head; 24: cylinder head cover; 25: piston; 26: connecting rod; 27: combustion chamber; 28: intake passage; 29: exhaust passage; 30: supercharging passage; 31: ignition plug; 32: supercharger; 33, 34: crank shaft ■ — ■ ■ — holder; 35, 36: ball bearing; 37: AC generator; 38: radiator; 39: cooling fan; 40: oil pump; 41: oil filter; 42: timing gear; 43: cam shaft; 44: cam gear; 45: support shaft; 46: cam follower group; 47: pull rod group; 48: rocker arm shaft; 49: rocker arm group; 50: intake valve; 51: exhaust valve; 52: supercharging valve; 53: driving gear; 60: clutch; 61: clutch shaft; 62: driven gear; 63, 64: ball bearing; 70: non-stage transmission; 70a: speed change portion; 70b: output portion; 71: transmission shaft; 72: ball bearing; 73: oil pump; 74: oil filter; 75: cone; 76: cone holder; 77: driving face; 78: driven face; 79: roller bearing; ;80: electric motor; 81: ball bearing; 82: output shaft; 83, 84: ball bearing; 85: intermediate shaft; 86: input gear; 87: output gear; 88: input gear; 89: pinion shaft; 90: pinion gear; 91: ring gear; 92: speed reduction case portion; 93, 94: ball bearing; 95: differential case; 96L, 96R: axle pipe; 97: pinion shaft; 98, 99: pinion gear; 100, 101: side gear; V: motor tricycle; F: vehicle body frame; P: power unit; Wf: front wheel; Wr: rear wheel; E: internal combustion engine; M: transmission device; C: transmission case; L1 to L6: axis; Rl: intermediate speed reduction device; R2: final speed reduction device; D: differential device. We Claim: 1. A power unit (P) mounted on a vehicle comprising an internal combustion engine (E), a speed change gear (70) comprising a speed change portion (70a) to which power of a crank shaft (20) of said internal combustion engine (E) is transmitted and an output portion (70b) for outputting the, power speed-changed by said speed change portion (70a), a final speed reduction device (R2) to which the power of said output portion (70b) is transmitted through an intermediate speed reduction device (R1), and a transmission case (c), containing said speed change gear, the power from said final speed reduction device (R2) being transmitted to a driving shaft, characterized in that said intermediate speed reduction device (Rl) and said final speed reduction (R2) device are contained in said transmission case (c), said speed change portion (70a) is disposed on the side of said internal combustion engine (E), whereas said output portion (70b) is disposed on the side opposite to said internal combustion engine with respect to said driving shaft, and said speed change gear (70) is disposed on the upper side of said intermediate speed reduction device (Rl) disposed on the upper side of said final speed reduction device (R2); and the power unit P is swingable about the axis in the right-left direction of the left and right bushes (12) with respect to main frame. A power unit mounted on a vehicle as claimed in claim 1, wherein said speed change gear (70) comprises a speed change gear shaft (71) for transmitting power to said speed change portion (70a) by being drive-connected to said crank shaft (20) through a clutch (60) having a clutch shaft (61) disposed on the upper side of said crank shaft (20), said clutch shaft (61) is coaxial with said speed change gear shaft (71), and said clutch (60) is disposed side by side with said crank shaft (20) in the longitudinal direction. A power unit mounted on a vehicle as claimed in claim 2, wherein said crank shaft (20) is disposed directed in the longitudinal direction, a cylinder (22) of said internal combustion engine (E) having a substantially horizontal center axis is disposed on one lateral side in the right-left direction with respect to said crank shaft '(20), and said clutch (60), said speed change gear (70) and said intermediate speed reduction device (Rl) having rotational axes parallel to the rotational axis of said crank shaft (20) are disposed on the other lateral side in the right-left direction with respect to said crank shaft (20). , A power unit mounted on a vehicle substantially as hereinbefore described with reference to the accompanying drawings. Dated this the 18th day of July, 2001

Full Text

FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
PROVISIONAL/COMPLETE SPECIFICATION
[See Section 10]
"POWER UNIT MOUNTED ON VEHICLE"

HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-kU, Tokyo, Japan
The following specification particularly describes the nature of the invention and the manner in which it is to be performed :-

Granted

31-5-2006

18 JUL 2001

[Detailed Description of the Invention]
[Technical Field to which the Invention Pertains] The present invention relates to a power unit mounted on a vehicle and transmitting the power of an internal combustion engine to a driving shaft through a clutch, a speed change gear and a speed reduction device, and more particularly to a layout structure of the internal combustion engine, the clutch, the speed change gear and the speed reduction device constituting the power unit. [0002]-
[Prior Art]
Hithterto, as a device of this type, there has been known the driving device of a four-wheel motor vehicle disclosed in Japanese Utility Model Open No. Hei 4-28116. The driving device comprises an engine with a crank shaft disposed longitudinally with respect to the vehicle body, a first input shaft operated in conjunction with the crank shaft through a speed reduction gear and a clutch, a transmission comprising a speed change mechanism, a second input shaft to the speed change mechanism and an output shaft from the speed change mechanism, and a pair of gears for operating the first input shaft and the second input shaft in conjunction with each other. The second input shaft, the speed change mechanism and the

output shaft constituting the transmission are disposed in a gear case, and the output shaft and a rear wheel driving shaft are operated in conjunction with each other through a bevel gear constituting a final speed reduction device.
[Problem to Be Solved by the Invention]
According to the prior art as above, the speed change mechanism connected to the second input shaft extending rearward from the engine disposed on the front side of the rear wheel driving shaft is disposed on the rear side of the rear wheel driving shaft, so that the masses of the driving device including the engine are not concentrated in the longitudinal direction, and there is room for improvement in drivability. In addition, the gear case is inevitably enlarged, and the driving device constituted of the engine and the transmission is • inevitably enlarged, so that the degree of freedom in layout of the members disposed in the periphery of the driving device is restricted, and the vehicle body is enlarged in size in the longitudinal direction. Besides, since the output shaft is coaxial with the input shaft of the final speed reduction device, the speed change mechanism having a relatively large diameter is disposed

in the vicinity of the rear wheel driving shaft in the upper-lower direction, so that there is the drawback that the minimum height from the ground of the vehicle is lowered.
The present invention has been made in consideration of the above-mentioned situations, and, accordingly, it is an object of the present invention to contrive mass concentration and compact design in a power unit mounted on a vehicle and to prevent the minimum height from the ground of the vehicle from being lowered.
[Means for Solving the Problem and Effects of the Invention]
The invention as set forth in claim 1 of the present application resides in a power unit mounted on a vehicle comprising an internal combustion engine, a speed change gear comprising a speed change portion to which power of a crank shaft of the internal combustion engine is transmitted and an output portion for outputting the power speed-changed by the speed change portion, a final speed reduction device to which the power of the output portion is transmitted through an intermediate speed reduction device, and a transmission case containing the

speed change gear, the power from the final speed reduction device being transmitted to a driving shaft, wherein the intermediate speed reduction device and the final speed reduction device are contained in the transmission case, the speed change portion is disposed on the side of the internal combustion engine whereas the output portion is disposed on the side opposite to the internal combustion engine with respect to the driving shaft, and the speed change gear is disposed on the upper side of the intermediate speed reduction device disposed on the upper side of the final speed reduction device.
According to the invention as set forth in claim 1, the speed change portion of the speed change gear is disposed on the side of the internal combustion engine with respect to the driving shaft, so that the speed change portion occupying a large weight in the speed change gear is disposed relatively close to the internal combustion engine large in weight, and concentration of masses in the power unit mounted on the vehicle is accomplished. In addition, since the intermediate speed reduction device and the final speed reduction device are in an upper-and-lower positional relationship, both the speed reduction devices are disposed side by side in the

longitudinal direction, and, since the speed change portion is disposed on the side of the internal combustion engine while the output portion is disposed on the side opposite to the internal combustion engine with respect to the driving shaft, the distance between the output portion and the driving shaft can be reduced, so that the transmission case containing the speed change gear, the intermediate speed reduction device and the final speed reduction device can be made compact. Furthermore, in the power unit, the speed change gear is disposed on the upper side of the intermediate speed reduction device located on the upper side of the final speed reduction device, so that the speed change gear is located relatively away from the driving shaft in the vertical direction, and, therefore, the minimum height from the ground of the vehicle is prevented from being lowered due to the speed change gear.
As a result, in the power unit, mass concentration is achieved, and drivability of the vehicle is enhanced. In addition, since the transmission case can be made compact, the power unit is made compact, and the degree of freedom in laying out the members disposed in the periphery of the power unit is increased. Furthermore,

the minimum height from the ground of the vehicle is prevented from being lowered due to the layout of the speed change gear of the power unit.
The invention as set forth in claim 2 resides in a power unit mounted on a vehicle as set forth in claim 1, wherein the speed change gear comprises a speed change gear shaft for transmitting power to the speed change portion by being drive - connected to the crank shaft through a clutch having a clutch shaft disposed on the upper side of the crank shaft, the clutch shaft is coaxial with the speed change gear shaft, and the clutch is disposed side by side with the crank shaft in the l'ongitudinal direction.
According to the invention as set forth in claim 2, in addition to the effects of the invention as set forth in claim 1, the clutch shaft and the speed change gear shaft are coaxial with each other, so that the crank shaft is located nearer to the driving shaft than the clutch and the speed change gear and, therefore, the center of gravity of the vehicle can be lowered. In addition, since the clutch shaft and the speed change gear shaft are coaxial with each other and the clutch

having the clutch shaft is disposed side by side with the crank shaft in the longitudinal direction, the speed change gear can be located near to the internal combustion engine in the longitudinal direction, which also ensures that concentration of masses in the longitudinal direction can be achieved in the power unit, and the power unit is made compact in the longitudinal direction.
As a result, of the effects of the invention as set forth in claim 1, the concentration of masses and compact design in the power unit can be further promoted, and the center of gravity of the vehicle can be lowered, whereby running stability is enhanced.
The invention as set forth in claim 3 resides in a power unit mounted on a vehicle as set forth in claim 2, wherein the crank shaft is disposed directed in the longitudinal direction, a cylinder of the internal combustion engine having a substantially horizontal center axis is disposed on one lateral side in the right-left direction with respect to the crank shaft, and the clutch, the speed change gear and the intermediate speed reduction device having rotational axes parallel to the

rotational axis of the crank shaft are disposed on the other lateral side in the right-left direction with respect to the crank shaft.
According to the invention as set forth in claim 3, in addition to the effects of the invention as set forth in claim 2, since the clutch, the speed change gear and the intermediate speed reduction device having rotational axes parallel to the rotational axis of the crank shaft are disposed on the side opposite to the side where the cylinder occupying a large space is disposed with respect to the crank shaft, the component elements of the power unit can be laid out in a compact configuration in the periphery of the rotational axis of the crank shaft, and accessory parts (for example, an air cleaner) of the internal combustion engine and parts to be fitted to the vehicle body can be disposed in a space formed at the direct rear of the cylinder on the side where the cylinder is disposed. In addition, since the center axis of the cylinder is substantially horizontal, the center of gravity of the internal combustion engine can be lowered, and, hence, the center of gravity of the vehicle can be lowered.

As a result, of the effects of the invention as set forth in claim 2, the lowering of the center of gravity of the vehicle can be further promoted, the component elements of the power unit can be laid out in a compact configuration in the periphery of the rotational axis of the crank shaft, the power unit can be made compact with the rotational axis of the crank shaft as a center, and parts can be laid out by utilizing the space formed at the direct rear of the cylinder, whereby the vehicle body can be made compact.
The terms "upper", "lower", "front", "rear", "left" and "right" used herein mean the "upper", "lower", "font", "rear", "left" and "right" with respect to the vehicle body.
[Mode for Carrying Out the Invention]
Now, an embodiment of the present invention will be described below referring to Figs. 1 to 4.

According to the present invention there is provided a power unit mounted on a vehicle comprising an internal combustion engine, a speed change gear comprising a speed change portion to which power of a crank shaft of said internal combustion engine is transmitted and an output portion for outputting the power speed-changed by said speed change portion, a final speed reduction device to which the power of said output portion is transmitted through an intermediate speed reduction device, and a transmission case, containing said speed change gear, the power from said final speed reduction device being transmitted to a driving shaft, characterized in that said intermediate speed reduction device and said final speed reduction device are contained in said transmission case, said speed change portion is disposed on the side of said internal combustion engine, whereas said output portion is disposed on the side opposite to said internal combustion engine with respect to said driving shaft, and said speed change gear is disposed on the upper side of said intermediate speed reduction device disposed on the upper side of said final speed reduction device; and
the power unit P is swingable about the axis in the right-left direction of the left and right bushes with respect to main frame. [BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS] [Fig. 1]
Fig. 1 is a left side view of major part showing the positional relationship between a vehicle body frame

and a power unit of a motor scooter type motor tricycle on which the power unit of the present invention is mounted.
[Fig. 2]
Fig. 2 is a rear view of a section passing through the center axis of the cylinder, showing the positional relationships of rotational axes of shafts. [Fig. 3]
Fig. 3 is a sectional view taken generally along line III-III of Fig. 2. [Fig. 4]
Fig. 4 is a sectional view taken generally along line IV-IV of Fig. 1.
Fig. 1 is a left side view of essential portions showing the positional relationship between a vehicle body frame F and a power unit P of a motor scooter type motor tricycle V on which a power unit according to the present invention is mounted. The motor tricycle V

comprising a single front wheel Wf which is a driven wheel and a pair of left and right rear wheels Wr which are driving wheels comprises the vehicle body frame F which has a main frame comprising a front frame 1 whose rear portion is branched into left and right portions and a pair of left and right rear frames 2 connected to the rear portions of the front frame 1 by bolts, and a sub-frame 3 .
A steering mechanism 4 for steering the front wheel Wf and a front suspension mechanism 6 having a swing arm 5 swingably supported about an axis in the right-left direction at a lower portion of a front portion of the front frame 1 and supporting the front "wheel Wf are * provided at the front portion of the front frame 1. A Neidhart mechanism 7 comprising a cylindrical portion, a shaft portion inserted in the cylindrical portion and a rubber-made elastic body fitted in a radial gap between the cylindrical portion and the shaft portion is fitted to a rear portion of the front frame 1 through a plate 8, and a power unit P for driving the left and right rear wheels Wr is supported on the right-left pair of sub-frames 3 connected to the cylindrical portion of the Neidhart mechanism 7 by bolts. Further, a seat 9 is

disposed on the upper side of the rear portion of the front frame 1, and a storage box 10 having an opening portion opened and closed by the seat 9 and storing goods such as a helmet and the like is provided on the lower side of the seat 9.

A front portion of the power unit P comprising a water-cooled type internal combustion engine E and a transmission device M is supported on the sub-frames 3 by a pair of hanger bolts respectively inserted through hanger holes of brackets 11 respectively fitted to the sub-frames 3 and a right-left pair of bushes 12 (in Fig. 1, the left bush 12 is shown) provided on the internal combustion engine E. The lower end of a rear portion of the power unit P is supported by a bush (not shown) provided at a right side portion of a transmission case C in which the transmission device M is contained, on the front side of a rear axle 13, and the upper end of the rear portion of the power unit P is supported on the sub-frames 3 through a buffer 14 supported between rear end portions of the sub-frames 3 whose rear portions are bent to be close to each other at a roughly central .position in the right-left direction of the vehicle body. By this arrangement, the power unit P is swingable about the axis

in the right-left direction of the left and right bushes 12 and swingable about the axis in the longitudinal direction of the Neidhart mechanism 7, with respect to the main frame.
Next, the internal combustion engine E and the transmission device M for transmitting the power of the internal combustion engine E to the rear wheels Wr which constitute the power unit P will be further described, referring to Fig. 2 which is a rear view of a section passing through the center axis L2 of a cylinder 22 for illustrating the positional relationship of rotational axes of shafts. Fig. 3 which is a sectional view taken generally along line III-"III of Fig. 2, and Fig. 4 which is a sectional view taken generally along line IV-IV of Fig. 1.

The transmission device M comprises a centrifugal clutch 60, a cone type non-stage transmission 70, an intermediate speed reduction device Rl and a final speed reduction device R2. Of these components, the clutch 60 is contained in a crankcase 21 of the internal combustion engine E, whereas the non-stage transmission 70, the intermediate speed reduction device Rl and the final

speed reduction device R2 are contained in the transmission case C.
Referring to Figs. 2 and 4, the internal combustion engine E is a single-cylinder 4-cycle internal combustion engine, and a crank shaft 20 is longitudinally disposed with its rotational axis L1 disposed in the longitudinal direction of the vehicle body, and is disposed in a substantially central position in the right-left direction of the vehicle body. A cylinder 22 having a center axis L2 substantially horizontal to the rotational axis L1 of the crank shaft 20, namely, extending to the right or to a slantly right upper side in the range of 0
to 20 , in this embodiment extending to a slightly slantly right upper side is disposed on the right side of the crank shaft 20, whereas the clutch 60, the non-stage transmission 70, the intermediate speed reduction device Rl and the final speed reduction device R2 are disposed on the left side of the crank shaft 20. Further, a clutch shaft 61 of the clutch 60 and a transmission shaft 71 of the non-stage transmission 70 are coaxial with each other, and their rotational axes L3, L4 are parallel to the rotational axis L1, and are disposed on the slantly left upper side at an angle larger than the center axis of the

cylinder 22 from the horizontal direction with respect to the rotational axis L2
A crankcase 21 of the internal combustion engine. E is split at a plane containing the rotational axis L2 and being ar.thogtonal to the center axis L2 of the cylinder 22, into a. right; crankcase 21R formed integrally with the cylindex." 2:2 by casting and a left crankcase 21L. containing the clutch 6 0 therein. A cylinder. head. 2:3; and a cylinder head cover 24 are sequentially mounted on: the cylinder 22. A piston 25 slidably fitted in the. cyiinder 22 and reciprocated is connected to the crank shaft. 2.0: through a connecting rod 26,. whereby the crank, shaft; 2:0; is driven to rotate The cylinder head 23 is: provided:, with.an intake passage 28" opened into a combustion chamber:27, an exhaust passage. 2 9. and a supercharging passage: 30, and is fitted, with, an ignition.-, plug 3:1, for. igniting a mixture gas: of a: fuel inje;cted;.:£rcair;:.a-£u.ei., ignition valve into the intake passage 28 and intake air Further, a compound operation.type piston type supercharger 32 having a reciprocating supercharging, piston 32a is provided on the upper side of the. cylinder 22. The supercharging piston 32a.is driven to reciprocate by driving the supercharging crank shaft drive-connected

to the supercharging piston 32a to rotate at the same rotating speed as a cam shaft 43 (described later) through a transmission belt wrapped around the supercharging crank shaft and the cam shaft 43.
Referring to Fig. 3, the crank shaft 20 is rotatably supported by crank shaft holders 33, 34 consisting of a pair of plates disposed at a predetermined spacing therebetween in the longitudinal direction and connected to the crankcase 21 and the cylinder 22 by a plurality of bolts fastened in the direction of the rotational axis LI, through ball bearings 35, 36 which are a pair of main bearings.
An AC generator 37 is provided at a front end portion of the crank shaft 20 extending more to the front side than ball bearing 35, and a cooling fan 39 for feeding cooling wind to a radiator 38 disposed on the front side of a rotor of the AC generator 37 integrally fixed to the crank shaft 20 is integrally rotatably connected to the rotor.
A trochoid type oil pump 40 is provided on the rear side of the crank shaft 20, and a rotor is driven to

rotate inside a pump casing fixed to the crankcase 21 by a hollow pump driving shaft 40a consisting of a piping fixed to a rear end portion of the crank shaft 20 extending more to the rear side than the ball bearing 36. An oil sucked from an oil pool at a bottom portion of the crankcase 21 and discharged from the oil pump 40 is supplied to parts to be lubricated of the internal combustion engine E, the clutch 60, the non-stage transmission 70 and the like through an oil passage formed of the hollow portion of the pump driving shaft 40a, then through oil passages provided in the crankcase 21, the cylinder 22 and the cylinder head 23 and through an oil filter 41 (See Fig. 1) fitted to a left side portion of the transmission case C.
Referring to Fig. 2, a timing gear 42 connected to a rear end portion of the crank shaft 20 is meshed with a
cam gear 44 connected to a cam shaft 43 rotatably
-. i f supported on the crank shaft holders 33, 34, and the cam
shaft 43 is driven to rotate at a speed reduction ratio
of 1/2 relative to the crank shaft 20. Intake, exhaust
and supercharging cams provided on the cam shaft 43
respectively swing intake, exhaust and supercharging cam
followers constituting a cam follower group 46 swingably

supported on a support shaft 45 supported by the crank shaft holders 33, 34. The motions of the cam followers respectively swing intake, exhaust and supercharging rocker arms constituting a rocker arm group 49 swingably supported on a rocker arm shaft 48 provided at the cylinder head 23 through intake, exhaust and supercharging pull rods constituting a pull rod group 47, and an intake valve 50, an exhaust valve 51 and a supercharging valve 52 respectively in contact with the rocker arms open and close opening portions of an intake passage 28, an exhaust passage 29 and a supercharging passage 30 on the side of the combustion chamber 27 at predetermined timings.
A driving gear 53 provided on the outer periphery of a rear portion crank web of the crank shaft 20 is meshed with a driven gear 62 rotatably fitted to the clutch shaft 61 and rotated at the same rotating speed with the driving gear 53, and the power of the crank shaft 20 is transmitted to a transmission shaft 71 of the non-stage transmission 70 spline-connected to the clutch shaft 61 rotatably supported on the crank shaft holder 33, 34 through a pair of ball bearings 63, 64 respectively mounted on the crank shaft holders 33, 34. Thus, the

clutch 60 is disposed between the crank shaft holders 33 and 34, and, therefore, the clutch 60 and the clutch shaft 61 are disposed in side-by-side relation in the longitudinal direction with the crank shaft 20 which is disposed on the slantly right lower side of them.
The clutch 60 as a starting clutch comprises a bowl - shaped clutch outer 60a integrally rotatably connected to the clutch shaft 61, and a drive plate 60b disposed on the inside of the clutch outer 60a, drive-connected to the driven gear 62 and rotatably fitted to the clutch shaft 61. When the driven gear 62 is rotated at a rotating speed higher than a predetermined rotating speed of the internal combustion engine E, a plurality of clutch shoes 60c swingably supported on the drive plate 60b are swung radially outwards by centrifugal forces against the springy force of a clutch spring 60d, and friction members provided at outer peripheral surfaces of the clutch shoes 60c come into contact with the inner peripheral surface of the clutch outer 60a, whereby the clutch 60 comes into a connected condition, and the rotation of the driven gear 62 is transmitted to the clutch shaft 61.

The transmission shaft 71 to which the power of the clutch shaft 61 is transmitted has its front end portion rotatably supported on the crank shaft holders 33, 34 at a portion of spline connection with the clutch shaft 61 together with a rear end portion of the clutch shaft 61 on the outer peripheral side thereof through a ball bearing 64, and has its rear end portion rotatably supported on the transmission case C through a ball bearing 72. The non-stage transmission 70 comprises a speed change portion 70a for changing the rotating speed of the transmission shaft 71, and an output portion 70b for outputting the power at the rotating speed changed by the speed change portion 70a. The speed change portion 70a is disposed on the side of the internal combustion engine E which is the front side with respect to the rear axle 13 as a driving shaft in the longitudinal direction, whereas the output portion 70b is disposed on the opposite side of the internal combustion engine E which is the rear side with respect to the rear axle 13, namely, on the side opposite to the side of the internal combustion engine E with respect to the rear axle 13 in the longitudinal direction. A trochoid type oil pump 73 is provided at a portion of the transmission shaft 71 on the rear side of the ball bearing 72, and an oil sucked

through an oil filter 74 is supplied to the speed change portion 70a and the like through an oil passage provided in the inside of the transmission shaft 71.
The speed change portion 70a comprises a cone holder 76 holding a plurality of cones 75 arranged in a ring form around the transmission shaft 71 and being movable in the direction of the rotational axis L4 of the transmission shaft 71, a driving face 77 integrally rotatably connected to the transmission shaft 71 and having an outer peripheral surface in contact with each of the cones 75, a driven face 78 rotatably supported on the transmission shaft 71 through a roller bearing 79 and having an inner peripheral surface in contact with each of the cones 75, and an electric motor 80 (See Figs. 1 and 4) for moving the cone holder 76 in the direction of the rotational axis L4. The output portion 70b comprises an output gear 82 rotatably supported on the transmission shaft 71 through a ball bearing 81 and integrally rotatably connected to the driven face 78. The non-stage transmission 70 is provided with an input rotating speed sensor and an output rotating speed sensor which are not shown; based on rotating speeds detected by the sensors, the rotation of the electric motor 80 is controlled by an

electronic control device so as to obtain a speed change ratio set according to throttle valve opening and rotating speed which show the operating conditions of the internal combustion engine E, whereby the cone holder 76 is moved in the direction of the rotational axis L4 .
The output gear 82 located on the rear side of the rear axle 13 is meshed with a first intermediate input gear 86 provided at a front portion of an intermediate shaft 85 disposed on the lower side of the transmission shaft 71 and rotatably supported on the transmission case C through a pair of ball bearings 83, 84. A first intermediate output gear 87 is provided at a rear portion of the intermediate shaft 85, and the first intermediate output gear 87 is meshed with a second intermediate input gear 88 which is integrally rotatably connected to a rear portion of a pinion shaft 89 provided with a pinion gear 90 constituting the final speed reduction device R2 together with a ring gear 91 (See Fig. 4) and which is constituted of a gear larger in diameter than the first intermediate output gear 87. A front portion of the pinion shaft 89 is rotatably supported on a speed reduction case portion 92 provided as a portion of the transmission case C through a ball bearing 93, and a rear

portion of the pinion shaft 89 is rotatably supported on the transmission case C through a ball bearing 94. Therefore, the first intermediate input gear 86, the first intermediate output gear 87 and the second intermediate input gear 88 constitute the intermediate speed reduction device R1 which transmits the power from the output portion 70b of the non-stage transmission 70 to the pinion shaft 89 by reducing the rotating speed.
As shown in Fig. 4, the pinion gear 90 is meshed with the ring gear 91 spline-connected to a differential case 95 contained in the speed reduction case portion 92, and final speed reduction of the rotating speed of the crank shaft 20 is conducted. A left axle pipe 96L containing a left rear axle 13L therein and a right axle pipe 96R containing a right rear axle 13R therein are respectively connected by bolts to a left opening portion and a right opening portion of the speed reduction case portion 92.
A differential device D comprises the differential case 95, a pinion shaft 97 fixed by penetrating through the inside of the differential case 95, a pair of pinion gears 98, 99 fixed to both ends of the pinion shaft 97,

and a right-left pair of side gears 100, 101 meshed with the pinion gears 98, 99. The left rear axle 13L and the right rear axle 13R are spline - connected to the left and right side gears 100, 101, respectively.
By such constitution of the transmission device M, the power of the crank shaft 20 is transmitted to the clutch 60 through the driven gear 62 meshed with the driving gear 53, and the power of the clutch shaft 61 of the clutch 60 is transmitted to the speed change portion 70a through the transmission shaft 71 of the non-stage transmission 70. Speed change is carried out in the speed change portion 70a so as to obtain a speed change ratio set according to the operating conditions of the internal combustion engine E, and the power thus speed-changed is transmitted from the output gear 82 to the final speed reduction device R2 through the intermediate speed reduction device Rl, and then through the differential device D to the left and right rear axles 13, whereby the rear wheels Wr are driven.
Here, referring to Fig. 2, the layout of the crank shaft 20, the clutch shaft 61, the transmission shaft 71, the intermediate shaft 85 and the pinion shaft 89 for

transmitting the power of the crank shaft 20 to the rear axles 13 will be described. The rotational axis L5 of the intermediate shaft 85 parallel to the rotational axis L1 of the crank shaft 20 is located on a slightly slantly left upper side of the rotational axis L1 of the crank shaft L1 and is located lower than the rotational axis L4 of the transmission shaft 71 and closer to the rotational axis L1. The rotational axis L6 of the pinion shaft 89 parallel to the rotational axis L1 of the crank shaft 20 is located on a slightly slantly left lower side of the rotational axis L1 of the crank shaft 20 and is located lower than the rotational axis L5 of the intermediate shaft 85 and closer to the rotational axis L1. Therefore, the transmission shaft 71, the intermediate shaft 85 and the pinion shaft 89 are located more closer to the rotational axis L1 of the crank shaft 20 in this order. By this layout, masses can be concentrated in the right-left direction in the power unit P, and the transmission case C can be made compact.
Next, the effects of the embodiment constituted as described above will be described.
Since the speed change portion 70a of the non-stage transmission 70 is disposed on the side of the internal

combustion engine E with respect to the rear axles 13, the speed change portion 70a occupying a large weight in the non-stage transmission 70 is located comparatively close to the internal combustion engine E having a large weight, so that mass concentration is achieved in the power unit P mounted on the motor tricycle V which is a vehicle. In addition, since the intermediate speed reduction device Rl and the final speed reduction device R2 are in an upper-lower positional relationship, both the speed reduction devices Rl, R2 are disposed side by side in the longitudinal direction. Further, since the speed change portion 70a is disposed on the side of the internal combustion engine E while the output portion 70b is disposed on the opposite side of the internal combustion engine E with respect to the rear axles 13, the distance between the output gear 82 and the rear axles 13 in the longitudinal direction can be reduced, so that the transmission case C containing the non-stage transmission 70, the intermediate speed reduction device Rl and the final speed reduction device R2 can be made compact in the longitudinal direction. Furthermore, since the non-stage transmission 70 is disposed on the upper side of the intermediate speed reduction device Rl located on the upper side of the final speed reduction

device R2 in the power unit P, the non-stage transmission 70 is located comparatively away from the rear axles 13 in the vertical direction, so that the minimum height from the ground of the vehicle can be prevented from being lowered due to the transmission.
As a result, mass concentration is achieved in the power unit P, and the drivability of the motor tricycle V is enhanced. In addition, since the transmission case C can be made compact in the longitudinal direction, the power unit P is made compact in the longitudinal direction, and the degree of freedom in layout of the members disposed in the periphery of the power unit P is increased. Further, the minimum height from the ground of the motor tricycle V is prevented from being lowered due to the layout of the non-stage transmission 70 of the power unit P.
Since the crank shaft 20 is located nearer to the rear axles 13 than the clutch 60 and the non-stage transmission 70 having the clutch shaft 61 and the transmission shaft 71 coaxial with each other, the center of gravity of the motor tricycle V can be lowered. In addition, since the clutch shaft 61 and the transmission

shaft 71 are coaxial with each other and the clutch 60 having the clutch shaft 61 is disposed side by side with the crank shaft 20 in the longitudinal direction, the non-stage transmission 70 can be disposed close to the internal combustion engine E in the longitudinal direction, and, in this point, also, masses can be concentrated in the longitudinal direction in the power unit P, which is made compact in the longitudinal direction. As a result, the mass concentration and compact designing of the power unit P can be further promoted, and the center of gravity of the motor tricycle V can be lowered, which ensures enhanced running stability.
Since the cylinder 22 occupying a large space is disposed on the right side of the crank shaft 20 while the clutch 60, the non-stage transmission 70, the intermediate shaft 85 and the pinion shaft 89 respectively having the rotational axes L3, L4, L5 and L6 parallel to the rotational axis L1 of the crank shaft 20 are disposed on the right side of the crank shaft 20, these component elements of the power unit P can be disposed in a compact configuration in the periphery of the rotational axis L1 of the crank shaft 20, and

accessory parts (for example, air cleaner) of the internal combustion engine E and parts to be fitted to the vehicle body can be disposed in the space formed at the direct rear of the cylinder 22 on the side where the cylinder 22 is disposed. Besides, since the center axis L2 of the cylinder 22 is substantially horizontal, the center of gravity of the internal combustion engine E can be lowered, and, hence, the center of gravity of the motor tricycle V can be lowered.
As a result, the lowering of the center of gravity of the motor tricycle V can be promoted, and the clutch 60, the non-stage transmission 70, the intermediate shaft 85 and the pinion shaft 89 which are component elements of the power unit P are disposed in a compact configuration in the periphery of the rotational axis L1 of the crank shaft 20, so that the power unit P can be made compact with the rotational axis L1 as a center, and parts can be disposed utilizing the space formed at the direct rear of the cylinder 22, whereby the vehicle body can be made compact.
Further, since the transmission shaft 71, the intermediate shaft 85 and the pinion shaft 89 having the

rotational axes L4 , L5 and L6 parallel to the rotational axis L1 of the crank shaft 20 occupy positions closer to the rotational axis L1 of the crank shaft 20 in this order, mass concentration in the right-left direction can be achieved in the power unit P, and the transmission case C can be made small in size. As a result, the drivability of the motor tricycle V is enhanced, and the power unit P is made compact in the longitudinal direction.
Now, as to embodiments obtained by modifying part of the constitution of the above-described embodiment, the modified constitution will be described.
While the non-stage transmission 70 is of the cone type in the above embodiment, a swash-type non-stage transmission and other single-shaft type transmission may be used. Besides, while the vehicle is a motor tricycle in the above embodiment, the vehicle may be a motorcycle or a four-wheel motor vehicle.

[Description of Reference Numerals]
1: front frame; 2: rear frame; 3: sub-frame; 4: steering mechanism; 5: swing arm; 6: front suspension mechanism; 7: Neidhart mechanism; 8: plate; 9: seat; 10: storage box; 11: bracket; 12: bush; 13: rear axle; 14: buffer;
20: crank shaft; 21: crankcase; 22: cylinder; 23: cylinder head; 24: cylinder head cover; 25: piston; 26: connecting rod; 27: combustion chamber; 28: intake passage; 29: exhaust passage; 30: supercharging passage; 31: ignition plug; 32: supercharger; 33, 34: crank shaft
■ — ■ ■ —

holder; 35, 36: ball bearing; 37: AC generator; 38: radiator; 39: cooling fan; 40: oil pump; 41: oil filter; 42: timing gear; 43: cam shaft; 44: cam gear; 45: support shaft; 46: cam follower group; 47: pull rod group; 48: rocker arm shaft; 49: rocker arm group; 50: intake valve; 51: exhaust valve; 52: supercharging valve; 53: driving gear;
60: clutch; 61: clutch shaft; 62: driven gear; 63, 64: ball bearing;
70: non-stage transmission; 70a: speed change portion; 70b: output portion; 71: transmission shaft; 72: ball bearing; 73: oil pump; 74: oil filter; 75: cone; 76: cone holder; 77: driving face; 78: driven face; 79: roller bearing; ;80: electric motor; 81: ball bearing; 82: output shaft; 83, 84: ball bearing; 85: intermediate shaft; 86: input gear; 87: output gear; 88: input gear; 89: pinion shaft; 90: pinion gear; 91: ring gear; 92: speed reduction case portion; 93, 94: ball bearing; 95: differential case; 96L, 96R: axle pipe; 97: pinion shaft; 98, 99: pinion gear; 100, 101: side gear;
V: motor tricycle; F: vehicle body frame; P: power unit; Wf: front wheel; Wr: rear wheel; E: internal combustion engine; M: transmission device; C:

transmission case; L1 to L6: axis; Rl: intermediate speed reduction device; R2: final speed reduction device; D: differential device.

We Claim:
1. A power unit (P) mounted on a vehicle comprising an internal combustion engine (E), a speed change gear (70) comprising a speed change portion (70a) to which power of a crank shaft (20) of said internal combustion engine (E) is transmitted and an output portion (70b) for outputting the, power speed-changed by said speed change portion (70a), a final speed reduction device (R2) to which the power of said output portion (70b) is transmitted through an intermediate speed reduction device (R1), and a transmission case (c), containing said speed change gear, the power from said final speed reduction device (R2) being transmitted to a driving shaft, characterized in that
said intermediate speed reduction device (Rl) and said final speed reduction (R2) device are contained in said transmission case (c), said speed change portion (70a) is disposed on the side of said internal combustion engine (E), whereas said output portion (70b) is disposed on the side opposite to said internal combustion engine with respect to said driving shaft, and said speed change gear (70) is disposed on the upper side of said intermediate speed reduction device (Rl) disposed on the upper side of said final speed reduction device (R2); and

the power unit P is swingable about the axis in the right-left direction of the left and right bushes (12) with respect to main frame.
A power unit mounted on a vehicle as claimed in claim 1, wherein said speed change gear (70) comprises a speed change gear shaft (71) for transmitting power to said speed change portion (70a) by being drive-connected to said crank shaft (20) through a clutch (60) having a clutch shaft (61) disposed on the upper side of said crank shaft (20), said clutch shaft (61) is coaxial with said speed change gear shaft (71), and said clutch (60) is disposed side by side with said crank shaft (20) in the longitudinal direction.
A power unit mounted on a vehicle as claimed in claim 2,
wherein said crank shaft (20) is disposed directed in the
longitudinal direction, a cylinder (22) of said internal
combustion engine (E) having a substantially horizontal
center axis is disposed on one lateral side in the right-left
direction with respect to said crank shaft '(20), and said
clutch (60), said speed change gear (70) and said
intermediate speed reduction device (Rl) having rotational
axes parallel to the rotational axis of said crank shaft (20) are
disposed on the other lateral side in the right-left direction
with respect to said crank shaft (20). ,

A power unit mounted on a vehicle substantially as hereinbefore described with reference to the accompanying drawings.
Dated this the 18th day of July, 2001

Documents:

692-mum-2001-cancelled pages(31-5-2006).pdf

692-mum-2001-claims(granted)-(31-5-2006).doc

692-mum-2001-claims(granted)-(31-5-2006).pdf

692-mum-2001-correspondence(16-11-2006).pdf

692-mum-2001-correspondence(ipo)-(11-10-2006).pdf

692-mum-2001-drawings(3-9-2001).pdf

692-mum-2001-form 1(18-7-2001).pdf

692-mum-2001-form 18(13-7-2005).pdf

692-mum-2001-form 1a(31-5-2006).pdf

692-mum-2001-form 2(granted)-(31-5-2006).doc

692-mum-2001-form 2(granted)-(31-5-2006).pdf

692-mum-2001-form 3(18-7-2001).pdf

692-mum-2001-form 3(31-5-2006).pdf

692-mum-2001-form 5(18-7-2001).pdf

692-mum-2001-petition under rule 137(31-5-2006).pdf

692-mum-2001-power of authority(19-11-2001).pdf

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Patent Number

203165

Indian Patent Application Number

692/MUM/2001

PG Journal Number

19/2007

Publication Date

11-May-2007

Grant Date

11-Oct-2006

Date of Filing

18-Jul-2001

Name of Patentee

HONDA GIKEN KOGYO KABUSHIKI KAISHA

Applicant Address

1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	ATSUSHI OGASAWARE	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHI, 4-1, CHOU 1- CHOME, WAKO-SHI, SAITAMA, JAPAN.
2	TAKAFUMI ASAKURA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHI, 4-1, CHOU 1- CHOME, WAKO-SHI, SAITAMA, JAPAN.

PCT International Classification Number

N/A

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2000-237602	2000-08-04	Japan