Title of Invention

CHANGEOVER CLUTCH

Abstract

A changeover clutch which is interposed between an output shaft (8) of an internal combustion engine (0) and an input shaft of a gear transmission whose transmission ratio is changed over by a speed changing operation and wherein clutch connection/ disconnection is performed by a changeover operation, characterized in that a damper (57) is interposed between an output member of said changeover clutch and a driven member connected to said input shaft of said gear transmission, an automatic centrifugal clutch (13) for disposed at the output shaft (8) and changeover clutch and automatic centrifugal clutch are absorbed by the same damper.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10] "CHANGEOVER CLUTCH" 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 :- The present invention relates to changeover clutch. [Detailed Description of the Invention] [0001] [Technical Field to which the Invention Pertains] This invention relates to a changeover clutch interposed between an output shaft of an internal combustion engine and an input shaft of a gear transmission and has a superior damper function. [0002] [Prior Art] In a conventional changeover clutch wherein clutch connection/disconnection is performed by a clutch operation, as disclosed in the official gazette of Japanese Utility Model Publication No. Sho 57-29070 and the official gazette of Japanese Patent Laid-Open No. Hei 9-264337, a damper is interposed between an input gear "wheel which meshes with an output gear wheel integral with a crankshaft of an internal combustion engine and a clutch housing of a changeover clutch, and a clutch inner member connected to the clutch housing through a ■■ plurality of clutch disks is integrally coupled to the input shaft of the gear transmission by spline fitting. [0003] [Problems to be Solved by the Invention] Where an output member of the changeover clutch is integrally coupled to the input shaft of the gear transmission in this manner, impulsively high torque which is generated upon connection of the changeover clutch is liable to be transmitted to the gear transmission. [0004] [Means for Solving the Problems and Effects] The present invention relates to improvements in a changeover clutch which overcomes- such a drawback as described above, and according to the invention a changeover clutch which is interposed between an output shaft of an internal combustion engine and an input shaft of a gear transmission whose transmission ratio is changed over by a speed changing operation and. wherein clutch connection/disconnection is performed by a 'changeover operation is - characterized in that a damper is interposed between an output member of the changeover .clutch and a driven member connected to the input shaft of the gear transmission. [0005] In the invention , -since the damper is interposed between the output member of the changeover clutch and the driven member connected to the input shaft of the gear transmission, impulsive great torque variation caused by connection/disconnection of the changeover clutch is absorbed by the damper, and application of impulsively high torque to the gear transmission apparatus of the power transmission destination side is prevented and generation of noise, an impact or vibrations can be prevented. [Brief Description of the Drawings] [FIG. 1] FIG. 1 is a view of an appearance of a single-cylinder OHC four-stroke cycle internal combustion engine which includes a multiple disk clutch according to an embodiment of the present invention. [FIG. 2] FIG. 2 is a vertical sectional view of essential part of the internal combustion engine. [FIG. 3] FIG. 3 is a vertical sectional view of the multiple disk clutch according to the embodiment of the present invention. [FIG. 4] FIG. 4 is a view illustrating operation of the multiple disk clutch. [FIG. 5] FIG. -5 is a front elevational view of a housing of an automatic centrifugal clutch for starting in the embodiment. [FIG. 6] FIG. 6 is a horizontal sectional view of the housing of the automatic centrifugal clutch. [FIG. 7] FIG. 7 is a partial enlarged sectional view of a one-way clutch of the automatic centrifugal clutch for starting. Q [0006] [Mode for Carrying Out the Invention] In the following, an embodiment of the present invention shown in FIGS. 1 to 7 is described. [0 0 07] A body of a single-cylinder OHC four-stroke cycle internal combustion engine 0 carried on a motorcycle not shown includes, as shown in FIGS. 1 and 2, a cylinder block 1 having a cylinder hole 5 directed substantially forwardly (rightwardly in FIG. 1, upwardly in FIG. 2) in a horizontal direction, a cylinder head 2 disposed at the front end of the cylinder block 1, and leftwardly and rightwardly split right crankcase 3 and left crankcase 4 disposed at the rear end of the cylinder block 1. The leftwardly and rightwardly split right crankcase 3 and left crankcase 4 are coupled to each other by a bolt not shown, and the cylinder block 1, cylinder head 2, right crankcase 3 and left crankcase 4 are coupled integrally by bolts 6 which extend through the cylinder head 2 and the cylinder block 1 from the front side of the vehicle body and are screwed in the right crankcase 3 and the left crankcase 4. [0008] As shown in FIG. 2, a piston 7 is fitted for sliding movement in the cylinder hole 5 of the cylinder block 1, and a crankshaft 8 directed in a vehicle widthwise direction is supported for rotation on the right crankcase 3 and the left crankcase 4 by ball bearings 9. The piston 7 and the crankshaft 8 are connected to each other by a connecting rod 10 such that the crankshaft 8 is driven to rotate in the clockwise direction in FIG. 1 in an interlocking relationship with reciprocating motion of the piston 7. [0009] Further, a main shaft 11 and an output shaft 12 are supported for rotation in parallel to the crankshaft 8 on the right crankcase 3 and the left crankcase 4 (FIG. 1). A automatic centrifugal clutch 13 for starting shown in FIG. 3 is disposed at the right end of the crankshaft 8, and a changeover clutch 3 6 shown in the same figure is disposed at the right end of the main shaft 11. Gear wheels not shown are provided on the main shaft 11 and the output shaft 12. A driving sprocket wheel not shown is mounted integrally at the left end of the output shaft 12 which projects leftwardly from the left crankcase 4 while a driven sprocket wheel (not shown) is mounted integrally on a rear axle integral with a rear wheel not shown, and an endless chain (not shown) extends between and around the driving sprocket wheel and the driven sprocket wheel. In a state wherein the automatic centrifugal clutch 13 for starting and the changeover clutch 36 are connected, the rear wheel not shown is driven to rotate at a predetermined transmission ratio through selective meshing engagement of the gear wheels of the main shaft 11 and the output shaft 12. [0010] In the automatic centrifugal clutch 13 for starting described above, as shown in FIGS. 3 and 4, a centrifugal clutch inner member 14 is fitted for rotation at a right side portion of the crankshaft 8, and a clutch center 15 is spline fitted with the right end of the crankshaft 8 at a position displaced to the outer end of the centrifugal clutch inner member 14. The clutch center 15 is coupled integrally to the crankshaft 8 by a nut 16 screwed at the right end of the crankshaft 8. A retainer 18 for a one-way clutch 17 is interposed between a circular recessed inner circumferential face 14b of an outer side disk portion 14a of the centrifugal clutch inner member 14 and an outer circumferential face 15a of the clutch center 15 as shown in FIGS. 3 and 6. Roller holding holes 18a are formed at fixed distances over a circumferential direction in the retainer 18 as shown in FIG. 6, and a roller 19 is loosely fitted in each of the roller holding holes 18a. As shown FIGS. 6 and 7, a clutch cam concave face 15b is formed on the outer circumferential face 15a of the clutch center 15. [0011] The clutch cam concave face 15b is inclined moderately in a radial direction toward the clockwise direction from a bottom portion thereof and is inclined steeply in a radial direction toward the counterclockwise direction from the bottom portion so that, when the clutch center 15, that is, the crankshaft 8, rotates in the clockwise direction in FIG. 6 (the single-cylinder OHC four-stroke cycle internal combustion engine 0 rotates forwardly), running torque of the clutch center 15 is not transmitted to the centrifugal clutch inner member 14, but when the clutch center 15 rotates in the counterclockwise direction in FIG. 6 (the single-cylinder OHC four-stroke cycle internal combustion engine 0 rotates reversely), running torque of the clutch center 15 is transmitted to the centrifugal clutch inner member 14, or when the centrifugal clutch inner member 14 rotates in the clockwise direction in FIG. 6, running torque of the centrifugal clutch inner member 14 is transmitted to the clutch center 15. [0012] A ring-shaped spring 20 for positioning is interposed between the clutch center 15 and the retainer 18 such that the roller holding hole 18a of the retainer 18 can be returned to the position confronting with the bottom portion of the clutch cam concave face 15b of the clutch center 15 by spring force of the spring 20. [0013] Further, a cup-shaped clutch housing 21 formed from a steel plate is jointed integrally to an outer peripheral face of a right side portion of the clutch center 15 by welding. The clutch housing 21 is a press-shaped article. [0014] An outer peripheral portion 21b of a disk-shaped portion 21a of the clutch housing 21 formed by pressing is bent leftwardly substantially at the right angle in cross section with respect to the disk-shaped portion 21a, and swollen portions 21c are formed at equal distances over a circumferential direction as shown in FIG. 5. An opening 21d is formed at a position displaced to the center in every other one of the swollen portions 21c, and an arresting pawl 21e for supporting a support ring 25 is formed by cutting and raising intermediately between each adjacent ones of the openings 21d. The disk-shaped portion 21a, outer peripheral portion 21b, swollen portions 21c, openings 21d and arresting pawls 21e of the clutch housing 21 are formed at a time upon pressing. [0015] A cover 22 for covering the clutch center 15 and the nut 16 positioned at the center of the disk-shaped portion 21a of the clutch housing 21 is mounted integrally on the disk-shaped portion 21a of the clutch housing 21 by means of bolts 23. A weight cam 24 is loosely fitted in each of the openings 21d of the clutch housing 21 and is supported for rocking motion on the support ring 25 held between the disk-shaped portion 21a and the arresting pawls 21e of the clutch housing 21. [0016] Further, a large number of engaging recesses 14c are formed at equal distances over a circumferential direction on the outer side disk portion 14a of the centrifugal clutch inner member 14 as shown in FIG. 6, and inner circumferential projections 26a of a clutch plate 26 are fitted in the engaging recesses 14c of the centrifugal clutch inner member 14. Friction plates 27 are adhered integrally to the opposite side faces of the clutch plate 26. [0017] Furthermore, as shown in FIG. 3, outer circumferential projections 28a of two pressure plates 28 are fitted on the swollen portions 21c of the clutch housing 21 such that they hold the clutch plate 26 therebetween. Several guide pins 29 are caulked integrally at several locations over a circumferential direction on the right side one of the two pressure plates 28 such that they extend leftwardly. An end portion of each of the guide pins 29 is loosely fitted in the pressure plate 28 on the left side, and a coil spring 30 is fitted around each of the guide pins 29. Several spacers 31 are caulked integrally at several locations over a circumferential direction on the left side face of the right pressure plate 28. The inner face of each of the swollen portions 21c of the clutch housing 21 acts as a stopper, and the pressure plates 28 are rotated integrally with the clutch housing 21. [0018] When the crankshaft 8 and the clutch center 15 stop or are rotating at a speed lower than a predetermined speed, high centrifugal force does not act upon the weight cam 24, and the clutch plate 26 and the pressure plates 28 are spaced away from each other as shown in FIG. 3, thereby providing a clutch disconnected state. [0019] Further, if the crankshaft 8 and the clutch center 15 rotate at a speed higher than the predetermined speed in the clockwise direction in FIGS. 5 and 6, then the weight cam 24 shown in FIG. 3 is rocked in the clockwise direction until it is inclined as seen in FIG. 4 by centrifugal force acting upon the weight cam 24. By the inclination of the weight cam 24, the right side pressure plate 28 is pushed leftwardly so that the clutch plate 26 and the pressure plates 28 are contacted under pressure with each other with the friction plates 27 interposed therebetween, and by frictional force by the pressure contact, running torque of the crankshaft 8, that is, the clutch center 15, is transmitted to the centrifugal clutch inner member 14. [0020] Furthermore, an output gear wheel 3 3 is formed integrally at the left end of the centrifugal clutch inner member 14, and a gear noise reduction mechanism 34 is disposed adjacent the output gear wheel 33. A gear wheel 3 8 is formed on a clutch outer member 37 which corresponds to a clutch housing of the changeover clutch 36 and is held in meshing engagement with the output gear wheel 33 and the gear noise reduction mechanism 34. The gear noise reduction mechanism 34 is normally held in meshing engagement under pressure with a power non-transmission side gear wheel of the gear wheel 38 of the changeover clutch 36 by spring force of a spring 35 so that a back lash is removed. [0021] Besides, a kick starter gear wheel not shown or an output gear wheel of a starter motor is held in meshing engagement with the output gear wheel 33 integral with the centrifugal clutch inner member 14. If a kick pedal not shown is operated or the starter motor is started, then torque in the clockwise direction in FIG. 5 is applied to the output gear wheel 33 and the one-way clutch 17 is brought into a connection state. Consequently, the crankshaft 8 is driven to rotate in the clockwise direction to start the single-cylinder OHC four-stroke cycle internal combustion engine 0. [0022] A flanged tubular member 40 is spline fitted with a main shaft 3 9 which is an output shaft of the changeover clutch 36, and is secured by a nut 41 so that it cannot be pulled off. A torque receiving member 42 in the form of a thick disk is fitted for relative rotation with a tubular portion 40a of the flanged tubular member 40 and is secured by a circlip 43 which contacts with the right end face of the torque receiving member 42 so that it cannot be moved in an axial direction. The clutch outer member 37 is fitted for relative rotation on an outer peripheral face of the torque receiving member 42 in the form of a thick disk and is secured by a circlip 44 which contacts with the left end face of the torque receiving member 42 so that it cannot be moved in an axial direction. [0023] Further, a plurality of ribs 37a directed in an axial direction are formed over a circumferential direction on an inner circumferential face of the clutch outer member 37, and recessed portions (not shown) engageable with the ribs 37a of the clutch outer member 37 are formed on outer circumferential portions 45a of clutch plates 45. A clutch inner member 46 is positioned on the center side of the clutch outer member 37 and is fitted with the tubular portion 40a of the flanged tubular member 40 for relative rotation. [0024] Furthermore, a plurality of ribs 46a directed in an axial direction are formed over a circumferential direction on an outer circumferential face of the clutch inner member 46, and recessed portions (not shown) engageable with the ribs 46a of the clutch inner member 46 are formed on inner circumferential portions 47a of pressure plates 47. The clutch plates 45 and the pressure plates 47 are placed alternately such that they can contact with each other while they are held between the torque receiving member 42 and a right side plate portion 46b of the clutch inner member 46. [0025] A projection 46d projecting leftwardly is formed on a left side plate portion 46c of the clutch inner member 46 and a recess 42a is formed on the right side face of the torque receiving member 42 such that the torque receiving member 42 and the clutch inner member 46 can rotate integrally. [0026] A cone disk spring 48 is positioned on the right side of the left side plate portion 46c of the clutch inner member 46 and is loosely fitted on the tubular portion 40a of the flanged tubular member 40. A spring receiving portion 49 is disposed at a corner portion between the projection 46d and the left side plate portion 46c of the clutch inner member 46, and another spring receiving portion 50 is disposed in the proximity of an end portion of the tubular portion 40a. A circlip 51 for arresting the spring receiving portion 50 is fitted with the tubular portion 40a of the flanged tubular member 40 such that the clutch inner member 46 is biased toward the torque receiving member 42 by spring force of the cone disk spring 48. In a normal state, the clutch plates 45 and the pressure plates 47 contact under pressure with each other to connect the changeover clutch 36. [0027] Further, three or more holes 48a are formed at different locations in an equally spaced relationship over a circumferential direction in the cone disk spring 48, and tubular portions 46e are formed at locations on the clutch inner member 46 corresponding to the holes 48a of the cone disk spring 48. The clutch inner member 46 and a drawing out member 52 are coupled integrally by bolts 53 extending through a disk portion 52a of the drawing out member 52 and screwed in the tubular portions 46e of the clutch inner member 46. [0028] Furthermore, a drawing out shaft 55 is fitted for rotation in a tubular portion 52b of the drawing out member 52 through a bearing 54, and an operation member 56 is connected to the right end of the drawing out shaft 55. If the operation member 56 is moved rightwardly against the spring force of the cone disk spring 48, then also the drawing out member 52 and the clutch inner member 46 are moved rightwardly in an interlocking relationship therewith, whereupon the mutual contact between the clutch plates 45 and the pressure plates 47 is cancelled and the changeover clutch 36 is changed over to a disconnection state. [0029] A plurality of gear wheels are provided on each of the main shaft 39 and a countershaft not shown parallel to the main shaft 39, and form a gear transmission. [0030] Further, semi-cylindrical recesses 40c and 42b are formed at neighboring portions of a disk portion 40b of the flanged tubular member 40 and the torque receiving member 42, and a coil spring damper 57 is interposed between the semi-cylindrical recesses 40c and 42b. [0031] Since the embodiment shown in FIGS. 1 to 7 is configured in such a manner as described above, when the crankshaft 8 stops or is rotating at a speed lower than the predetermined speed, high centrifugal force does not act upon the weight cams 24 and the automatic centrifugal clutch 13 for starting remains in a disconnected state. [0032] Then, if the speed of rotation of the crankshaft 8 exceeds the predetermined speed, then the pressure plates 28 are pressed against the clutch plate 26 by the centrifugal force acting upon the weight cams 24 so that the automatic centrifugal clutch 13 for starting is placed into a connected state as shown in FIG. 4, and torque of the crankshaft 8 is transmitted to the clutch outer member 37 of the changeover clutch 36. [0033] Meanwhile, since the clutch housing 21 of the automatic centrifugal clutch 13 for starting is formed by stamping presswork of a steel plate such that the disk-shaped portion 21a, outer peripheral portion 21b, swollen portions 21c, openings 21d and arresting pawls 21e of the clutch housing 21 are formed simultaneously and integrally, a large number of complicated metal dies are not required, and the number of parts and the man-hours for working can be reduced. Further, since the clutch housing 21 can be formed from a thin copper plate, the productivity can be raised. As a result, reduction in weight and significant reduction of the cost can be achieved. [0034] Further, since, in a normal state wherein rightward operating force does not act upon the operation member 56, the changeover clutch 36 is in a connected state, if the speed of rotation of the crankshaft 8 exceeds the predetermined speed of rotation, then since also the automatic centrifugal clutch 13 for starting is in a connected state, also the main shaft 39 is driven to rotate. [0035] Furthermore, if the operation member 56 is operated rightwardly while the automatic centrifugal clutch 13 for starting and the changeover clutch 36 are in the connected state in this manner (FIG. 4), then the changeover clutch 36 is brought into a disconnected state, and running torque is not transmitted to the main shaft 39. Consequently, meshing engagement of the gear wheels provided on the main shaft 3 9 and the countershaft which is disposed in the proximity of and in parallel to the main shaft 39 can be selectively changed over. Then, if a connection/disconnection operation of the changeover clutch 36 and a speed changing operation of the gear transmission are performed, then the motorcycle not shown can travel with a required transmission ratio. [0036] Furthermore, since the gear wheel 38 is formed integrally on the clutch outer member 37 of the changeover clutch 36, the dimension of the entire changeover clutch 36 in the axial direction is reduced, and reduction of the number of parts, simplification of the configuration and reduction in size and weight of the changeover clutch 36 can be achieved. Also reduction of the cost can be achieved. [0037] Besides, since fluctuation of the torque applied from the automatic centrifugal clutch 13 for starting to the clutch outer member 37 of the changeover clutch 36 is first absorbed by mutual slipping between the clutch plates 45 and the pressure plates 47 and further absorbed by the coil spring damper 57 interposed between the flanged tubular member 40 and the torque receiving member 42, no great torque fluctuation is applied to the teeth of the gear wheels provided on the main shaft 39 and the countershaft not shown and the durability of the teeth of the gear wheels is improved. [0038] And, since high driving torque generated upon connection of the changeover clutch 36 is absorbed by the coil spring damper 57, impact force by a changing over operation of the changeover clutch 36 is less likely to be transmitted from the changeover clutch 36 to the gear transmission of the power transmission destination side inputted from the changeover clutch 36. [0039] While the embodiment described above relates to a case wherein the configuration of the present invention is applied to a multiple disk type changeover clutch, the configuration of the present invention can be applied not only to a changeover clutch of the multiple disk type, but also to a changeover clutch of any other type. Further, while the embodiment described above uses a spring as a damper, the damper need not be a spring but may be a damper which utilizes a hydraulic pressure. [Description of Reference Characters] 0 ... single-cylinder OHC four-stroke cycle internal combustion engine, 1 ... cylinder block, 2 ... cylinder head, 3 ... right crankcase, 4 ... left crankcase, 5 ... cylinder hole, 6 ... bolt, 7 ... piston, 8 ... crankshaft, 9 ... ball bearing, 10 ... connecting rod, 11 ... main shaft, 12 ... output shaft, 13 ... automatic centrifugal clutch for starting, 14 ... centrifugal clutch inner member, 14a ... outer side disk portion, 14b ... circular recessed inner circumferential face, 14c ... engaging recess, 15 ... clutch center, 15a ... outer circumferential face, 15b ... clutch cam concave face, 16 ... nut, 17 ... one-way clutch, 18 ... retainer, 18a ... roller holding hole, 19 ... roller, 20 ... spring, 21 ... clutch housing, 21a ... disk-shaped portion, 21b ... outer peripheral portion, 21c ... swollen portion, 21d ... opening, 21e ... arresting pawl, 22 ... cover, 23 ... bolt, 24 ... weight cam, 25 ... support ring, 26 ... clutch plate, 26a ... circumferential projection, 27 ... friction plate, 28 ... pressure plate, 28a ... outer circumferential projection, 29 ... guide pin, 30 ... coil spring, 31 ... spacer, 33 ... output gear wheel, 34 ...gear noise reduction mechanism, 35 ... spring, 36 ... changeover clutch, 37 ... clutch outer member, 37a ... rib, 38 ... gear wheel, 39 ... main shaft, 40 ... flanged tubular member, 40a ... tubular portion, 40b ... disk portion, 40c ... semi-cylindrical recess, 41 ... nut, 42 ... torque receiving member, 42a ... recess, 42b ... semi-cylindrical recess, 43 ... circlip, 44 ... circlip, 45 ... clutch plate, 45a ... outer circumferential portion, 46 ... clutch inner member, 46a ... rib, 46b ... right side plate portion, 46c ... left side plate portion, 46d ... projection, 46e ... tubular portion, 47 ... pressure plate, 47a ... inner circumferential portion, 48 ... cone disk spring, 48a ... hole, 49 ... spring receiving portion, 50 ... spring receiving portion, 51 ... circlip, 52 ... drawing out member, 53 ... bolt, 54 ... bearing, 55 ... drawing out shaft, 56 ... operation member, 57 ... coil spring damper. We claim: . 1. A changeover clutch which is interposed between an output shaft (8) of an internal combustion engine (0) and an input shaft of a gear transmission whose transmission ratio is changed over by a speed changing operation and wherein clutch connection/ disconnection is performed by a changeover operation, characterized in that a damper (57) is interposed between an output member of said changeover clutch and a driven member connected to said input shaft of said gear transmission. an automatic centrifugal clutch (13) for disposed at the output shaft (8) and changeover clutch and automatic centrifugal clutch are absorbed by the same damper. 2. A changeover clutch substantially as herein described with reference to the accompanying drawings. Dated this 19/03/2002

Documents:

264-mum-2002-abstract(16-08-2007).doc

264-mum-2002-abstract(16-08-2007).pdf

264-mum-2002-cancelled pages(16-08-2007).pdf

264-mum-2002-claims(granted)-(16-08-2007).doc

264-mum-2002-claims(granted)-(16-08-2007).pdf

264-mum-2002-correspondence(01-11-2007).pdf

264-mum-2002-drawing(02-05-2002).pdf

264-mum-2002-form 1(16-08-2007).pdf

264-mum-2002-form 1(19-03-2002).pdf

264-mum-2002-form 18(10-02-2006).pdf

264-mum-2002-form 2(granted)-(16-08-2007).doc

264-mum-2002-form 2(granted)-(16-08-2007).pdf

264-mum-2002-form 3(12-04-2004).pdf

264-mum-2002-form 3(16-08-2007).pdf

264-mum-2002-form 3(19-03-2002).pdf

264-mum-2002-form 3(31-07-2002).pdf

264-mum-2002-form 5(19-03-2002).pdf

264-mum-2002-petition under rule 138(16-08-2007).pdf

264-mum-2002-power of authority(16-08-2007).pdf

264-mum-2002-power of authority(20-05-2002).pdf

abstract1.jpg