Title of Invention

SUPPORT STRUCTURE OF CRANK SHAFT

Abstract

A support structure of a crank shaft in which a crank shaft (31) is rotatably supported by a crank case (29) to be divided by a plane having a rotational axis of the crank shaft (31) via bearings (84) arranged at positions sandwiching a crank pin (28) therebetween, wherein the inner race (86) of each bearing (84) is mounted on the crank shaft (31) at a position in a direction along an axis of the crank shaft (31) in such a way that it can not move relatively with respect to the crank shaft (31) and wherein the outer race (85) of each bearing (84) is mounted on the crank case (29) at a position in the direction along the axis of the crank shaft (31) in such a way that it can not move relatively with respect to the crank case (29).

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] \ PROVISIONAL/COMPLETE SPECIFICATION [See Section 10] 207033 16/05/07 SUPPORT STRUCTURE OF CRANK SHAFT 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 :- i. GRANTED 30/5/2005 The present invention relates to a support structure of a crank shaft. [DESCRIPTION OF THE RELATED ART] A conventional support structure of a crank shaft in which a crank shaft is supported by a crank case to be divided by a plane including a rotational axis of the crank shaft via a pair of ball bearings is disclosed in, for example, Japanese Examined Utility Model Publication No. H7-52413. [PROBLEMS TO BE SOLVED BY THE INVENTION] In the above-mentioned conventional support structure of a crank shaft, the outer race of one of a pair of ball bearings arranged at positions sandwiching a crank pin therebetween is mounted in a crank case at a predetermined position in the direction along the axis of a crank shaft, but there is no means for positioning the outer race of the other ball bearing in the direction along the axis of thecrank shaft between the outer race of the other ball bearing and the crank case, and the other ball bearing is positioned in the direction of the axis of the crank shaft by sandwiching the other ball bearing by the crank web of the crank shaft or the crank pin and the crank case. For this reason, there is a possibility that some assembling operations produce large variations in the relative position of the other ball bearing to the crank case in the direction along the axis of the crank shaft to reduce the durability of the ball bearing and to increase variations in the transmission of vibrations and noises caused by an explosive load to the crank case. The present invention has been made in view of the above circumstances. It is the object of the present invention to provide a support structure of a crank shaft in which the amount of vibrations of a bearing in the direction along the axis of a crank shaft is controlled in a desired range to improve the durability of the bearing and to prevent variations in the transmission of vibrations and noises thereof. lAccordingly, there is provided a support structure of a crank shaft in which a crank shaft is rotatably supported by a crank case to be divided by a plane having a rotational axis of the crank shaft via bearings arranged at positions sandwiching a crank pin therebetween, wherein the inner race of each bearing is mounted on the crank shaft at a position in a direction along an axis of the crank shaft in such a way that it can not move relatively with respect to the crank shaft and wherein the outer race of each bearing is mounted on the crank case at a position in the direction along the axis of the crank shaft in such a way that it can not move relatively with respect to the crank case. According to this constitution, since the bearings arranged at both sides of the crank pin are interposed between the crank shaft and the crank case in such a way that their relative positions with respect to the crank case along the axial direction of the crank shaft are determined, it is possible to control the amount of vibrations of the bearings along the direction along the axis of the crank shaft within a desired range to improve the durability of the bearings and it is also possible to reduce variations in the transmission of vibrations and noises to the crank case which are produced by an explosive load to prevent noises. Further, the invention set forth in claim 2 is characterized in that, in addition to the constitution of the invention set forth in the above-mentioned claim 1, the position of the above-mentioned each outer race in the direction along the axis of the crank shaft is determined by engaging a regulating member fitted on the outer peripheral portion of the each outer race with the crank case. According to this constitution, it is possible to control the position of the each bearing with respect to the crank case in the direction along the axis of the crank shaft with ease and high accuracy. still further, the invention set forth in claim 3 is characterized in that, in addition to the constitution of the invention set forth in the above-mentioned claim 1 or claim 2, the center position of the each outer race in the direction along the axis of the crank shaft is not aligned with the center position of the each inner race in the direction along the axis of the crank shaft in consideration of a difference in thermal expansion between the crank case and the crank shaft which are made of different materials from each other. According to this constitution, since the positions of the each outer race and the each inner race are determined in consideration of a difference in thermal expansion between the crank case and the crank shaft which are made of different materials from each other, it is possible to improve the durability of the bearing and to prevent noises more effectively. BRIEF DESCRIPTION OF THE INVENTION] FIG. 1]FIG. 1 is a general side view of a motorcycle of a cooter type. [FIG. 2]FIG. 2 is an enlarged view of an essential portion in FIG'. 1 . [FIG. 3]FIG. 3 is a cross - sectional view taken on a line 3-3 in FIG,. 1. [FIG. 4] FIG. 4 is a view when viewed from a line 4-4 with arrows,. [FIG. 5] FIG. 5 is an enlarged view of an essential portion in FIG,. 3. [FIG. 6] FIG. 6 is a cross - sectional view taken on a line 6-6 in FIG. 1. [PREFERRED EMBODIMENTS OF THE INVENTION] The preferred embodiment of the present invention will be described below on the basis of one preferred embodiment in accordance with the present invention shown in the accompanying drawings. FIG. 1 to FIG. 6 show one preferred embodiment in accordance with the present invention. FIG. 1 is a general side view of a motorcycle of a scooter type. FIG. 2 is an enlarged view of an essential portion in FIG. 1. FIG. 3 is a cross - sectional view taken on a line 3-3 in FIG. 1. FIG. 4 is a view when viewed from a line 4-4 with arrows. FIG. 5 is an enlarged view of an essential portion in FIG. 3. FIG. 6 is a cross - sectional view taken on a line 6-6 in FIG. 1. First, in FIG. 1 and FIG. 2, a vehicle body frame F of a scooter-type motorcycle V provided with a front wheel Wf steered by a steering handlebar 11 and a rear wheel Wr driven by a swing-type power unit P is divided into three parts of a front frame 12, a center frame 13, and a rear frame 14. The front frame 12 is constituted of an aluminum alloy cast integrally provided with a head pipe 121, a down tube 122 and a step floor support member 123. The center frame 13 supporting the power unit P in such a way that it can oscillate in the up-down direction via a pivot 15 is formed of an aluminum alloy cast and is joined to the rear end of the front frame 12. The rear frame 14 extending in the back and up direction of the power unit P is constituted of an annular pipe and a fuel tank 16 is supported by the upper surface thereof . A helmet case 17 is supported by the upper surface of the center frame 13 and the helmet case 17 and the fuel tank 16 are retractably covered with a cover 19 integrally having a sheet 18. The power unit P is integrally provided with a water-cooled one-cylinder four-cycle E whose cylinder is arranged toward the front of a vehicle body and a belt-type continuously variable transmission T extending from the left side of the engine E to the rear side of the vehicle body and the rear upper surface of the belt-type continuously variable transmission T is joined to the rear end of the center frame 13 via a rear cushion 20. An air cleaner 21 is supported by the upper surface of the belt-type continuously variable transmission T and a muffler 22 is supported by the right side surface of the belt-type continuously variable transmission T and a retractable main stand 23 is supported by the bottom surface of the engine E. In FIG. 3 and FIG. 4, the engine E is provided with a first engine block 32 and a second engine block 33 which are divided by a dividing plane 30 extending in a vertical direction along a crank shaft 31, and the first engine block 32 constitutes a cylinder block 321 and a crank case half part 322 and the second engine block 33 constitutes the remaining half part of the crank case 29 . In other words, the crank case 29 can be divided by a plane including the rotational axis of the crank shaft 31. To the front end of the first engine block 32 is joined a cylinder head 34 and to the front end of the cylinder head 34 is joined a head cover 35. To the right sides of the first and second engine blocks 32, 33 is joined a generator cover 36 . The belt-type continuously variable transmission T is provided with a right side casing 37 and a left side casing 38 which are to be joined to each other, and the front right side of the right side casing 37 is joined to the left side of the first and second engine blocks 32, 33 and to the rear right side of the right side casing 37 is joined a reduction gear casing 39. A piston slidably fitted in the cylinder 41 mounted on the first engine block 32 is connected to a crank shaft 31 via a connecting rod 43 and a crank pin 28. A cam shaft 44 is rotatably supported by the cylinder head 34 and an suction valve and an exhaust valve ( both not shown ) mounted on the cylinder head 34 are opened or closed by the cam shaft 44. In a chain passage 40 made in the first engine block 32 is received a timing chain 45 and the timing chain 45 is looped around a driving sprocket 46 mounted on the crank shaft 31 and a driven sprocket 47 mounted on the cam shaft 44. This produces one rotation of the cam shaft 44 per two rotations of the crank shaft 31. A driving pulley 54 is mounted on the left end of the crank shaft 31 projecting into the right side casing 37 and the left side casing 38. The driving pulley 54 is provided with a fixed side pulley half body 55 fixed to the crank shaft 31 and a movable side pulley half body 56 retractably moving to the fixed side pulley half body 55, and the movable side pulley half body 56 is energized in the direction getting near to the fixed side pulley half body 55 by an centrifugal weight 57 moving outside in the radial direction in response to the increasing rotational speed of the crank shaft 31. A driven pulley 59 fixed to an output shaft 58 supported between' the rear portion of the right side casing 37 and the reduction gear casing 39 has a fixed side pulley half body 60 relatively rotatably supported by the output shaft 58 and a movable side pulley half body 61 retractably getting near to the fixed side pulley half body 60 and the movable pulley half body 61 is energized toward the fixed side pulley half body 60 by a spring 62. A starting clutch 63 is provided between the fixed side pulley half body 60 and the output shaft 58. An endless V belt 64 is looped between the driving pulley 54 and the driven pulley 59. Between the right side casing 37 and the reduction gear casing 39 are supported an middle shaft 65 parallel to the output shaft 58 and an axle 66, and among the output shaft 58, the middle shaft 65 and the axle 66 is provided a reduction gear train 67 . On the right end of the axle 66 passing through the reduction gear casing 39 and projecting out to the right side is mounted the rear wheel Wr. In this way, the rotational power of the crank shaft 31 is transmitted to the driving pulley 54 and is then transmitted from the driving pulley 54 to the rear wheel Wr via the V belt 64, the driven pulley 59, the starting clutch 63 and the reduction gear train 67. when the engine E is rotated at low speeds, the centrifugal force applied to the centrifugal weight 57 of the driving pulley 54 is small and hence the width of the groove between the fixed side pulley half body 60 and the movable side pulley half body 61 is reduced by the spring 62 of the driven pulley 59 to make a speed change ratio "LOW". As the rotational speed of the crank shaft 31 increases from this state, the centrifugal force applied to the centrifugal weight 57 increases and the width of the groove between the fixed side pulley half body 55 of the driving pulley 54 and the movable side pulley half body 56 decreases and the width of the groove between the fixed side pulley half body 60 and the movable side pulley half body 61 of the driven pulley 59 increases, which in turn continuously increases a speed change ratio from "LOW" to "TOP". An alternating current generator mounted on the right side of the crank shaft 31 is covered with a generator cover 36 and on the right side of the generator cover 36 is mounted a radiator 69. In order to supply cooling air to the radiator 69, a cooling fan 70 fixed to the right end of the crank shaft 31 is interposed between the alternating current generator 68 and the radiator 69. A thermostat case 72 housing a thermostat 71 therein is joined to the right side of the cylinder head 34 and a cooling water pump 73 mounted on the right side of the cam shaft 44 is received in a space surrounded by the cylinder head 34 and the thermostat case 72. As is evident from FIG. 4, the front lower portion of the radiator 69 is connected to the thermostat case 52 by a cooling water pipe 74 and the thermostat case 52 is connected to the first engine block 32 by a cooling water pipe 75. To a rear fender 76 covering the rear wheel Wr from above is removably fixed a water supply pipe 77 connected to the rear upper portion of the radiator 69 and the water supply pipe 77 is connected to the cylinder head 34 by a cooling water pipe 78. In a state where the warming up of the engine E is completed, cooling water exhausted from the cooling water pump 73 driven by the cam shaft 44 is supplied to the water jackets of the first engine block 32 and the cylinder head 34 through the thermostat case 72 and the cooling water pipe 75 to cool the engine E while it passes through the water jackets and then is supplied to the radiator 69 through the cooling water pipe 78. The cooling water whose temperature is reduced while it passes through the radiator 69 is returned to the cooling water pump 73 through the cooling water pipe 74 and the thermostat 71. On the other hand, when the engine is being -warmed up and the temperature of the cooling water is low, the thermostat 71 is operated to circulate the cooling water in the engine E without passing it through the radiator 69, whereby the temperature of the cooling water is quickly increased. The cooling fan 70 and the radiator 69 arranged outside the cooling fan 70 are covered with a synthetic resin cover 80 fixed to the generator cover 36. To the cover 80 is fixed a louver 81 for making cooling air introduced into the cover 80 a laminar flow, for preventing noises generated in the cover 80 from leaking outside, for preventing foreign substances from entering the cover 80, and for introducing cooling air from outside into the radiator 69. The air introduced into the cover 80 from the louver 81 is sucked by the cooling fan 70 and is passed through the radiator 69 to cool the cooling water in the radiator 69 and is exhausted outside the cover 80. In this connection, the crank shaft 31 is rotatably supported by the crank case 29 via ball bearings 84 , 84 arranged at the positions sandwiching a crank pin 28 therebetween. In FIG. 5 and FIG. 6, the ball bearing 84 has a plurality of balls 87, 87, ... which are arranged between an outer race 85 and an inner race 86 and which are regulated in the circumferential direction by a retainer 88. In addition, the thickness of the outer race 85 is made larger than that of the inner race 86 and hence each ball 87, 87, ... is arranged at a position leaning inside from the center position between the outer periphery of the outer race 85 and the inner peripheral portion of the inner race 86. The inner races 86, 86 of these ball bearings 84, 84 are mounted on the crank shaft 31 at predetermined positions in the direction along the axis of the crank shaft 31 in such a way that they can not move relatively by pressing the crank shaft 31 into the inner races 84, 84. In this connection, the crank case 29 is constituted of the crank case half part 322 of the first engine block 32 and the second engine block 33, and semi - circular depressions 89, 89 made at the joint surface where the crank case half part 322 is joined to the second engine block 33 and semi - circular depressions 90, 90 made at the joint surface where the second engine block 33 is joined to the crank case half part 322 form circular support holes 91, 91 where the outer races 85, 85 of the ball bearings 84, 84 are fitted and supported. In the outer peripheral portions of the outer races 85, 85 of the ball bearings 84, 84 are made annular fitting grooves 92, 92. On the other hand, in the depressions 89, 89 constituting the half portions of the support holes 91, 91 are made engaging grooves 93, 93 corresponding to the fitting grooves 92, 92. In the half portions of the fitting grooves 92, 92 are fitted the inner peripheral portions of regulating members 94, 94 nearly shaped like a letter C and the outer peripheral portions of the regulating members 94, 94 are engaged with the engaging grooves 93, 93. Further, the outer diameters of the outer races 85, 85 are made slightly larger than the inner diameters of the support holes 91, 91, and when the regulating members 94, 94 are engaged with the engaging grooves 92, 92, the outer races 85, 85, which are positioned in the direction along the axis of the crank shaft 31, are sandwiched between the crank case half part 322 and the second engine block 33 which are fixed to each other. Accordingly, this results in mounting the outer races 85, 85 of the ball bearings 84, 84 in the crank case 29 at predetermined positions in the direction along the axis of the crank shaft 31 in such a way that they can not move relatively with respect to the crank case 29. Still further, the center positions of the outer races 85, 85 in the direction along the axis of the crank shaft 31 are not aligned with the center positions of the inner races 86, 86 in the direction along the axis of the crank shaft 31 in consideration of a difference in thermal expansion between the crank shaft case 29 and the crank shaft 31 which are made of different materials from each other. In this preferred embodiment, the crank shaft 31 is made of iron-based material and the crank case 29 is made of aluminum based material and the center positions of the outer races 85, 85 in the direction along the axis of the crank shaft 31 are shifted inside from those of the inner races 86, 86 in the direction along the axis of the crank shaft 31. Next, describing the action of the present preferred embodiment, the inner races 86, 86 of the ball bearings 84, 84 arranged at both sides of the crank pin 28 are mounted on the crank shaft 31 at predetermined positions in the direction along the axis of the crank shaft 31 in such a way that they can not move relatively with respect to the crank shaft 31 and the outer races 85, 85 of the ball bearings 84, 84 are mounted in the crank case 29 at predetermined positions in the direction along the axis of the crank shaft 31 in such a way that they can not move relatively with respect to the crank case 29, which results in interposing the ball bearings 84, 84 between the crank shaft 31 and the crank case 29 at predetermined positions relative to the crank case 29 in the direction along the axis of the crank shaft 31. Accordingly, this can control the amount of vibrations of the ball bearings 84, 84 in the direction along the axis of the crank shaft 31 within a desired range to improve the durability of the ball bearings 84, 84 and can reduce variations in the transmission of vibrations and noises caused by an explosive load to the crank case 29 to prevent noises from being produced, In addition, since the crank shaft 31 is pressed into the inner races 86, 86 of the ball bearings 84, 84, the inner races 86, 86 are mounted on the crank shaft 31 at predetermined positions in the direction along the axis of the crank shaft 31, and since the regulating members 94, 94 fitted on the outer peripheral portions of the outer races 85, 85 are engaged with the crank case 29, the outer races 85, 85 of the ball bearings 84, 84 are positioned in the direction along the axis of the crank shaft 31. Accordingly, it is possible to control the positions of the ball bearings 84, 84 with respect to the crank case 29 in the direction along the axis of the crank shaft 31 with ease and high accuracy. Since the center positions of the outer races 85, 85 in the direction along the axis of the crank shaft 31 is not aligned with the center positions of the inner races 86, 86 in the direction along the axis of the crank shaft 31 in consideration of a difference in thermal expansion between the crank shaft case 29 and the crank shaft 31 which are made of different materials from each other, it is possible to improve the durability of the ball bearings 84, 84 and to prevent noises from being produced more effectively. Further, since the thickness of the outer race 85 is made larger than that of the inner race 86, it is possible to provide the outer race 85 with a strength capable of resisting a comparatively large load applied to the outer race 85 sandwiched between the crank case half part 322 and the second engine block 33 when variations occur in the roundness of the support hole 91 made in the crank case 29. While the preferred embodiment has been described in detail up to this point, it is not intended to limit the present invention to the above-mentioned preferred embodiment, but it should be understood that other modifications may be made without departing from the scope of the present invention which has been set forth in the foregoing claims. For example, in the above-mentioned preferred embodiment, the inner race 86 is mounted on the crank shaft 31 at a predetermined position in the direction along the axis of the crank shaft 31 in such a way that it can not move relatively with respect to the crank shaft 31 by pressing the crank shaft 31 into the inner race 86, but it is also possible to mount the inner race 86 on the crank shaft 31 at a predetermined position in the direction along the axis of the crank shaft 31 by sandwiching the inner race 86 between the crank web of the crank shaft 31 and the pulley or the gear fixed to the crank shaft 31. [EFFECTS OF THE INVENTION] As described above, according to the invention set forth in claim 1, it is possible to control the amount of vibrations of the bearing in the direction along the axis of the crank shaft within a desired range to improve the durability of the bearing and to reduce variations in the transmission of vibrations and noises caused by an explosive load to the crank case to prevent noises from being produced. Further, according to the invention set forth in claim 2, it is possible to control the positions of the bearings with respect to the crank case in the axial direction of the crank shaft with ease and high accuracy. Still further, according to the invention set forth in claim 3, it is possible to determine the positions of the outer races and the inner races in consideration of a difference in thermal expansion which is produced by that the crank case and the crank shaft are made of different materials, which in turn can more effectively improve the durability of the bearing and prevent noises from being produced. [DESCRIPTION OF REFERENCE CHARACTERS] WE CLAIM : 1. A support structure of a crank shaft in which a crank shaft (31) is rotatably supported by a crank case (29) to be divided by a plane having a rotational axis of the crank shaft (31) via bearings (84) arranged at positions sandwiching a crank pin (28) therebetween, wherein the inner race (86) of each bearing (84) is mounted on the crank shaft (31) at a position in a direction along an axis of the crank shaft (31) in such a way that it can not move relatively with respect to the crank shaft (31) and wherein the outer race (85) of each bearing (84) is mounted on the crank case (29) at a position in the direction along the axis of the crank shaft (31) in such a way that it can not move relatively with respect to the crank case (29). A support structure of a crank shaft as claimed in claim 1, wherein a position of the each outer race (85) in the direction along the axis of the crank shaft (31) is determined by engaging a regulating member (94) fitted on the outer peripheral portion of the each outer race (85) with the crank case (29). 3. A support structure of a crank shaft as claimed in claim 1 or claim 2, wherein a center position of the each outer race (85) in the direction along the axis of the crank shaft (31) is not aligned with a center position of the each inner race (86) in the direction along the axis of the crank shaft (31) in consideration of a difference in thermal expansion between the crank case (29) and the crank shaft (31) which are made of different materials from each other. 4. A support structure of a crank shaft substantially as herein described with reference to the accompanying drawings. Dated this 4th day of May, 2000. (RITUSHKA NEGI) OF REMFRY & SAGAR AGENT FOR THE APPLICANTS 23

Documents:

412-mum-2000-cancelled page(4-5-2000).pdf

412-mum-2000-claim(granted)-(30-5-2005).doc

412-mum-2000-claim(granted)-(30-5-2005).pdf

412-mum-2000-correspondence(30-3-2006).pdf

412-mum-2000-correspondence(ipo)-(13-2-2007).pdf

412-mum-2000-drawing(4-5-2000).pdf

412-mum-2000-form 1(30-5-2005).pdf

412-mum-2000-form 1(31-5-2005).pdf

412-mum-2000-form 19-(16-4-2004).pdf

412-mum-2000-form 2(granted)-(30-5-2005).doc

412-mum-2000-form 2(granted)-(30-5-2005).pdf

412-mum-2000-form 3 (28-2-2001).pdf

412-mum-2000-form 3 (30-5-2005).pdf

412-mum-2000-form 3 (4-5-2000).pdf

412-mum-2000-form 5 (4-5-2006).pdf

412-mum-2000-power of authortiy(30-5-2005).pdf

412-mum-petittion under rule of 137-(30-5-2005).pdf

412-mum-petittion under rule of 138-(30-5-2005).pdf

412-mum-power of authorirty(04-09-2000).pdf

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