Title of Invention

A SOUND ARRESTING STRUCTURE FOR INTERNAL COMBUSTION ENGINE OF THE UNIT SWING TYPE

Abstract

A sound arresting structure for an internal combustion engine of the unit swing type which includes a V-belt automatic gear and is supported for rocking motion on a vehicle body, characterized in that an air cleaner is mounted on an outer periphery of a unit case, and an outer side wall of said air cleaner is extended to the outside of said unit case and covers an outer side face of said unit case.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] PROVISIONAL/COMPLETE SPECIFICATION [See Section 10] "A SOUND ARRESTING STRUCTURE FOR INTERNAL COMBUSTION ENGINE OF THE UNIT SWING TYPE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, having a place of business at 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 :- 23 MAR 2000 31 -5 – 2005 [Technical Field to which the invention Pertains] This invention relates to a sound arresting structure for an internal combustion engine of the unit swing type, and more particularly to a sound arresting structure for an internal combustion engine of the unit swing type which achieves reduction of transmission noise generated from a unit case.and intake noise generated from an air cleaner. [Prior Art] Conventionally, an internal combustion engine of the unit swing type is constructed such that, in order to reduce transmission noise generated from a unit case in which a power transmission apparatus-i-s accommodated, an outer side face of the unit case is covered' with a sound / arresting cover and a sound absorbing material is interposed between the sound arresting cover and the outer side face of the unit case (refer to the official gazette of Japanese Patent No. 2,796,3.05). Further, against intake noise generated from an air cleaner, the air cleaner is contrived in terms of the material, thickness, shape and so forth to provide a countermeasure. [Problem to be Solved by the Invention] However, where an outer side face of a unit case is covered with a sound arresting cover in order to reduce transmission noise generated from the unit case, a sound arresting cover for exclusive use is required, and there is a drawback that an increased number of parts are required. Meanwhile, even if an air cleaner is contrived in terms of the material, thickness, shape and so forth in order to reduce intake noise generated from the air cleaner, there is a limitation-to the reduction, and further reduction of noise_is demanded. It is a subject of the invention of the present application to solve such problems of conventional sound arresting structures for an internal combustion engine of the unit swing type as described above and provide a sound arresting structure for an internal combustion engine of the unit swing type which is less expensive and effective in reducing noise without increasing the number of parts. [Means for Solving the Problem and Effect] The present invention relates to a sound arresting structure for an internal combustion engine of the unit swing type which solves such problems as described above, and the invention as 'set forth'"in claim 1 provides a sound arresting structure for an internal combustion engine of the unit swing type which includes a V-belt automatic gear and is supported for rocking motion on a vehicle body, characterized in that an air cleaner is mounted on an outer periphery of a unit case, and an outer side wall of the air cleaner is extended to the outside of the unit case and covers an outer side face of the unit case. Accordingly, there is provided a sound arresting structure for an internal combustion engine of the unit swing type which includes a V-belt automatic gear and is supported for rocking motion on a vehicle body, characterized in that an air cleaner is mounted on an outer periphery of a unit case, and an outer side wall of said air cleaner is extended to the outside of said unit case and covers an outer side face of said unit case. Since the invention as set forth in claim 1 is constructed in such a manner as described above, the por.tion of the outer side wall of the air cleaner which is extended to the outside of the unit case can be used as a sound arresting cover, and consequently, the air cleaner can be used also as a sound arresting cover and transmission noise generated from the unit case can be reduced at a low cost without increasing the number of parts. Consequently, since the size of the air cleaner increases and the weight of the case increases within a reasonable range, the natural frequency of the air cleaner decreases and intake resonance vibrations are reduced, and consequently, intake noise to be generated from the air cleaner 25 can be decreased. Further, since the location where the unit case and the air cleaner are disposed is covered with a single plate, the appearance of the portion can be augmented. Furthermore, where the invention as set forth in claim 1 is constructed as set forth in claim 2, the sound absorbing material is disposed between the portion of the outer side wall of the air cleaner which is extended to the outside of the unit case and the outer side face of the unit case. As a result, transmission noise generated from the unit case and intake noise generated from the air cleaner are absorbed by the sound absorbing material, and those noises can be reduced further. [Mode for Carrying out the Invention] In the following, an embodiment of the present invention as set forth in claims l and 2 of! the present application shown in FIGS. 1 to 4 will be described. [Brief Description of the Accompany Drawing [FIG. 1] FIG. 1 is a left side elevational view of a motorcycle of the scooter type in which an internal combustion engine of the unit swing type to which a sound arresting structure of an embodiment of the present invention as set forth in claims 1 and 2 of the present application is applied is installed. [FIG. 2] FIG. 2 is a vertical sectional view taken along line II-II of FIG. 1. [FIG. 3] FIG. 3 is an enlarged view of a unit case and an air cleaner case of FIG. 1. [FIG. 4] FIG. 4 is a schematic sectional view taken along line IV-IV of FIG- 3. [FIG. 5] FIG. 5 is a view similar to FIG. 3 showing a modification to the embodiment of FIG. 1. [FIG. 6] FIG. 6 is a view similar to FIG. 4 showing another modification to the embodiment of FIG. 1. FIG. 1 is a left side elevational view of a motorcycle of the scooter type in which an.; internal combustion engine of the unit swing type to which a sound arresting structure of the present embodiment is applied is installed; FIG. 2 is a vertical sectional view taken along line II-II of FIG. 1; FIG. 3 is an enlarged view of a unit case and an air cleaner case of FIG. 1; and FIG. 4 is a schematic sectional view taken along line IV-IV of FIG. 3. Referring to FIGS. 1 and 2, a motorcycle 0 of the scooter type in which an internal combustion engine 1 of the unit swing type to which a sound arresting structure of the present embodiment is applied is installed includes a front fork 4 rotatably mounted on a head pipe 3 of a cradle type body frame 2 which forms a vehicle; body of the motorcycle 0 of the scooter type, and a front wheel 5 and a front fender 6 are mounted at a lower end of the front fork 4 while a handle bar 7 is connected to an upper end of the front fork 4. A fuel tank 8, a radiator reservoir tank 9, a radiator 10 and the internal combustion engine (hereinafter referred to as power unit) 1 of the unit swing type which includes a water-cooled internal combustion engine body 11 are disposed in a cradle space surrounded by the pipes of the body frame 2. The power unit 1 is mounted at a front portion thereof rather near to the center on the body frame 2 by a linkage 13, and a rear end portion of the power unit 1 is suspended on the body frame 2 by a rear cushion 14. A rear wheel 15 is mounted at a rear portion of the power unit 1. A seat 16 is disposed above a rear portion of the body frame 2, and a cover 17 which covers required portions of upper and lower faces, front and rear faces and the opposite left and right side faces of the vehicle body extends over an overall length of the body frame 2 from a front portion to a rear portion of A portion of the cover 17 from the middle to the rear half of the vehicle covers over the internal combustion engine body 11 of the power unit 1 and part of an air cleaner 25 and extends in an obliquely rearwardly upward direction. A window screen 12 which covers forward the handle bar 7 is provided contiguously to a front upper end of the cover 17. The power unit 1 includes the internal combustion engine body 11 and a power transmission apparatus for transmitting output power of the internal combustion engine body 11 to the rear wheel 15. The internal combustion engine body 11 is an internal combustion engine of the overhead cam (OHC) type, and a cylinder head 39 is connected integrally to a cylinder 33 by a bolt not shown. When a piston 34 is moved back and forth in the cylinder 33, the back and forth movement is converted into rotational movement of a crankshaft 23 through a connecting rod 35.. A driven side of a V-belt automatic gear 28 is connected to the left end in FIG. 2 of the crankshaft 23. The power transmission apparatus is formed from the V-belt automatic gear 28, a centrifugal clutch 18, a gear speed reduction apparatus 21 and so forth, and a mission case in which they are accommodated and a crankcase of the internal combustion engine body 11 are integrated with each other to form a unit case 20. The unit case 20 is formed in the following manner. The unit case 20 is formed from four case sections of a first case section 20a, a second case section 20b, a third case section 20c and a fourth case section 20d in order from the left in FIG. 2. The four case sections 20a to 20d are assembled into a unitary member by connecting each adjacent ones of them firmly to each ;other by means of bolts not shown. The second case section 20b includes a left half portion in FIG. 2 of a crankcase- corresponding portion of the unit case 20 when the crankcase-corresponding portion is divided into two in an axial direction of the cylinder and forms a right half portion in FIG. 2 of a mission case-corresponding portion of the unit case 20, and an accommodation section 22 for the gear speed reduction apparatus 21 is provided at a lower portion of the second case section 20b in FIG. 2. The third case section 20c includes a right half portion in FIG. 2 of the crankcase-corresponding portion of the unit case 20 when the crankcase-corresponding portion is divided into two in the axial direction of the cylinder and forms a left half portion in FIG. 2 of a case in which an alternator 24 is accommodated. The alternator 24 is mounted at a right end in FIG. 2 of the crankshaft 23 of the internal combustion engine body 11. The first case section 20a plays a role of a cover which covers the second case section 20b from leftwardly in FIG. 2. Meanwhile, the fourth case section 20d plays a role of a cover which covers the third case section 20c from rightwardly in FIG. 2. As shown in FIG. 1, the air cleaner. 25 is mounted above an outer periphery of the mission case-corresponding portion of the unit case 20. The case of the air cleaner 25 is made of a resin and is formed, as shown in FIG. 4, by connecting left and right half members integrally with each other at locations C1 to C5 in FIG. 3 by means of bolts not shown. Mounting of the air cleaner 25 on the unit case 20 is performed by connecting, at an A portion and a B portion in FIG. 3, a bracket provided in a projecting fashion on a bottom all of the air cleaner 25 by means of bolts to a boss portion formed upwardly in a swelling manner above the outer periphery of the unit case 20 An outer side wall 25a which forms a bottom wall portion of the left half member of the air cleaner 25 in FIG. 4 is extended to the outside of the mission case-corresponding portion of the unit case 2 0 and covers the outer side face of the mission case-corresponding portion as shown in FIGS. 1, 3 and 4. And, between the extension 25b and the outer side wall of the mission case-corresponding portion of the unit case 20 (the mission case-corresponding portion of the first case section 20a), a sound absorbing material 27 is disposed over an entire area (refer to a portion to which hatching lines of a checkered pattern are applied in FIGS. 1, 3 and 4). The sound absorbing material 27 absorbs transmission noise generated from the unit case 20 such as rotational sound of the crankshaft 23, frictional sound of the V-belt automatic gear,28 and meshing sound of gear wheels of the gear speed reduction apparatus 21 to reduce the noise level. The extension 25b described above is fastened by bolts at a plurality of locations (locations D1, D2 in FIG. 3) of the outer side wall of the mission case-corresponding portion of the unit case 20 (the mission case-corresponding portion of the first case section 20a) in a condition wherein the sound absorbing material 27 is held between the extension 25b and the outer wall face. By the construction described above, vibrations of the extension 25b can be suppressed and the mounting of the air cleaner 25 on the unit case 20 can be further strengthened, and motion of the air cleaner 25 is suppressed against violent upward and downward movements of the unit case 20 by convex and concave configurations of a road to prevent vibrations of the air cleaner 25 and stress loads acting upon the mounting portions A, B of the air cleaner 25 on the unit case 20 can be reduced. Though not particularly shown, an air intake portion 25c into the air cleaner 25 is provided in the outer side wall 25a of the air cleaner 25 (refer to FIG. 3) . An air intake of the air intake portion 25c is formed such that it is directed rearwardly of the vehicle (rightwardly in FIG. 3). An intake pipe 26 is connected to a vehicle forward portion of the air cleaner 25 (leftward in FIG. 1), and though not particularly shown, a carburetor is connected to an intermediate portion of the intake pipe 26. As shown in FIGS. 1 to 3, an air intake duct 2 9 for cooling the V-belt automatic gear 28 and so forth in the unit case 20 is mounted at a vehicle forward portion of the first case section 20a of the unit case 20. The air intake duct 29 is formed by assembling left and right half members (inner and outer side covers) 29a, 29b integrally with each other as shown in FIG. 2, and the air intake is provided on the vehicle rearward side of an upper extension of the air intake duct 29. When the air intake duct 29 is mounted onto the first case section 20a, the two half members 29a, 29b are fastened together at locations E, to E4 of FIG. 3 by bolts 30. It is to be noted that reference numeral 40 denotes an air exhaust port, which is provided at a lower portion of a vehicle rear portion of the unit case 20. A primary shaft 31 of the gear speed reduction apparatus 21 is received and supported for rotation by ball bearings on the opposite side walls which define the accommodation section 22 of the gear speed reduction apparatus 21. Further, an end portion of the primary shaft 31 at which the left clutch 18 in FIG. 2 is carried extends through the left side wall of the accommodation section 22 and is received and supported for rotation by a ball bearing on a bearing portion 32 formed in an inner wall of the first case section 20a. In this manner, since the primary shaft 31 is supported at three points thereof, the support thereof is solid. Thus, if the piston 34 is moved back and forth in the cylinder.33 when the internal combustion engine body 11 is in an operative condition, the back and forth movement thereof is converted into rotational movement of the crankshaft 23 through the connecting rod 35 so that the V-belt automatic gear 28 is rotated. As the speed of rotation of the V-b,elt automatic gear 28 rises, an inner member of the centrifugal clutch 18 which rotates integrally with the V-belt automatic gear 28 is brought into contact with an outer member of the clutch 18 to place the clutch 18 into a connected condition, and consequently, the rotational output of the clutch 18 is inputted to the gear speed reduction apparatus 21 through the primary shaft 31. The rotational output of the V-belt automatic gear 28 inputted to the gear speed reduction apparatus 21 is subsequently outputted as rotational movement of the rear wheel 15 mounted on a rear wheel axle 37 through a predetermined meshing engagement of gear wheels provided on the primary shaft 31, a countershaft 36 and the rear wheel axle 37 which is a final shaft. In the meantime, while transmission noise such as rotational sound of the crankshaft 23, fractional sound of the V-belt automatic gear 28 and meshing sound of the gear wheels of the gear speed reduction apparatus 21 is scattered to the outside through the unit case 20, it is absorbed by the sound absorbing material 27 disposed between the extension 25b of the air cleaner 25 and the outer side wall of the mission case-corresponding portion of the unit case 20 (the mission case-corresponding portion of the first case section 20a). Since the present embodiment is constructed in such a manner as described above, the following effects can be achieved.further. Since the portion 25b of the outer side wall 25a of the air cleaner 25 which is extended to the outside of the unit case 20 can be used as a sound arresting cover, the air cleaner 25 can be used also as a sound arresting cover, and transmission noise generated from the unit case 20 can be reduced at a low cost without increasing the number of parts. Consequently, since the size of the air cleaner 25 increases and the weight of the case increases within a reasonable range, the natural frequency of the air cleaner 25 decreases and intake resonance vibrations are reduced, and consequently, intake noise to be generated from the air cleaner 25 can be decreased. Further, since the location where the unit case 20 (mission case - corresponding portion) and the air cleaner 25 are disposed is ..covered with a single plate, the appearance of the portion can be augmented. Furthermore, since the sound absorbing material 27 is interposed between the portion 25b of the outer side wall 25a of the air cleaner 25 which is extended to the outside of the unit case 20 and the outer face of the unit case 20 (mission case-corresponding portion), transmission noise generated from the unit case 20 and intake noise generated from the air cleaner 25 are absorbed by the sound absorbing material 27, and those noises can be reduced further. While, in the present embodiment, the left half member (outer side cover) 29a in FIG. 2 of the air intake duct 29 is formed as a separate member from the portion 25b of the outer side wall 25a of the air cleaner 25 which is extended to the outside of the unit case 20, it is not limited to this, and the left half member 29a and the portion 25b may be formed as a unitary member using the same material. Referring to FIG. 5, reference numeral 38 denotes a sound arresting cover of a unitary member type formed in this manner. The sound arresting cover 38 of the unitary member type includes the outer side wall 25a of the air cleaner 25, the portion 25b of the outer side wall 25a which is extended to the outside of the unit case 20 and a portion corresponding to the left half portion 29a of the air intake duct 29. By the construction, since the outer side wall 25a of the air cleaner 25, the downward extension 25b of the air cleaner 25 and the left half member 29a of the air intake duct 2 9 are formed from a single common plate, the number of parts is further decreased. Further, since the weight of the case of the air cleaner 25 and the weight of the cover of the air intake duct 29 increase, the-natural frequencies of them decrease, and the intake resonance vibratipns are decreased. Also from this aspect, intake noise generated from the air cleaner 25 and intake noise generated from the air intake duct, 29 can be reduced. In addition, since the location where the unit case 20, air cleaner 25 and air intake duct 29 are disposed is all covered with a single plate (the sound arresting cover 38 of the unitary member type), the appearance of this portion can be further augmented. Further, while, in the present embodiment, the sound absorbing material 27 is not disposed on the outer side wall 25a of the air cleaner 25, it is; otherwise possible, as a modification to this, to dispose the sound absorbing material 27 also at the location as shown in FIG. 6 and form the sound arresting cover '39 as a single part and mount it such that it covers the sound absorbing material 27 from the unit case 20 over to the air cleaner 25. If this structure is employed, then intake noise generated from the air cleaner 25 can be further reduced. Further, where the structure described is employed, since movement of the air cleaner 25 can be suppressed better against violent upward and downward1 movements of the unit case 20 caused by concave and convex geometry of a road, vibrations of the air cleaner 25 can be further reduced and the stress loads acting upon the mounting portions A, B of the air cleaner 25 on the' unit case 20 can be further reduced. [Description of Reference Numerals] 0 ... motorcycle of the scooter type; 1 ... internal combustion engine of the unit swing type (power, unit); 2 ... body frame; 3 ... head pipe; 4 ... front fork; 5 ... front wheel; 6 ... front fender; 7 ... handle bar; 8 ... fuel tank; 9 ... radiator reservoir tank; 10 ... radiator; 11 ... internal combustion engine body; 12 ... window screen; 13 ... linkage; 14 ... rear cushion; 15 ... rear wheel; 16 ... seat; 17 ... cover; 18 ... clutch; 20 ... unit case; 20a to 20d ... first to fourth case section; 21 ... gear speed reduction apparatus; 2 2 ... accommodation section; 2 3 ... crankshaft; 2 4 ... alternator; 25 ... air cleaner; 25a ... outer side wall; 25b ... extension; 25c ... air intake portion; 26 ... intake pipe; 27 ... sound absorbing material; 28 ... V-belt automatic gear; 29 ... air intake duct (intake duct) ; 29a ... left half member (outer side cover) ; 29b ... right half member (inner side cover) ; 30 ... bolt; 31 ... primary shaft; 32 ... bearing portion; 33 ... cylinder; 34 ... piston; 35 ... connecting rod; 36 ... countershaft; 37 ... final shaft (rear wheel axle); 38, 39 ... sound arresting cover; 40 ... air exhaust port. WE CLAIM:- 1. A sound arresting structure for an internal combustion engine of the unit swing type which includes a V-belt automatic gear and is supported for rocking motion on a vehicle body, characterized in that an air cleaner is mounted on an outer periphery of a unit case, and an outer side wall of said air cleaner is extended to the outside of said unit case and covers an outer side face of said unit case. 2. A sound arresting structure for an internal combustion engine of the unit swing type as claimed in claim 1, wherein a sound absorbing material is disposed between the portion of said outer side wall of said air cleaner which is extended to the outside of said unit case and said outer side face of said unit case. 3. A sound arresting structure for an internal combustion engine of the unit swing type substantially as hereinbefore described with reference to the accompanying drawings. Dated this 23rd day of March, 2000. [SANJAY KUMAR] OF REMERY & SAGAR ATTORNEY FOR THE APPLICANTS

Documents:

261-mum-2000-cancelled pages(31-05-2005).pdf

261-mum-2000-claim(granted)-(31-05-2005).doc

261-mum-2000-claim(granted)-(31-05-2005).pdf

261-mum-2000-correspondence(03-06-2005).pdf

261-mum-2000-correspondence(ipo)-(13-02-2007).pdf

261-mum-2000-form 1(23-03-2000).pdf

261-mum-2000-form 1(31-05-2005).pdf

261-mum-2000-form 19(15-04-2004).pdf

261-mum-2000-form 2(granted)-(31-05-2005).doc

261-mum-2000-form 2(granted)-(31-05-2005).pdf

261-mum-2000-form 3(23-02-2001).pdf

261-mum-2000-form 3(23-03-2000).pdf

261-mum-2000-form 3(31-05-2005).pdf

261-mum-2000-form 5(23-03-2000).pdf

261-mum-2000-petition under rule 138(31-05-2005).pdf

261-mum-2000-power of authority(10-08-2000).pdf

261-mum-2000-power of authority(31-05-2005).pdf