Vehicle transmission

A vehicle transmission wherein a single shift spindle is provided with a master arm to operate the transmission via an accumulation mechanism and a clutch lever to operate a clutch, capable of more reliably realizing disconnection of the clutch after the completion of accumulation necessary for a shift operation. A vehicle transmission includes a master arm provided on a shift spindle for transmitting a rotational force to a shift drum of a transmission to rotate and operate the shift drum with a clutch lever provided on the shift spindle, to operate the clutch. An accumulation mechanism is capable of accumulating the rotational force transmitted from the shift spindle to the master arm. The master arm and the clutch lever are interlocked with each other. A delay mechanism is provided that delays the clutch disconnection operation with the clutch lever before accumulation is completed between the shift spindle and the clutch.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2012-082443 filed Mar. 30, 2012; Japanese Patent Application No. 2012-205673 filed Sep. 19, 2012 and Japanese Patent Application No. 2012-082442 filed Mar. 30, 2012 the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle clutch-interlock transmission.

2. Description of Background Art

JP-A No. 2001-280493 discloses, as a vehicle clutch-interlock transmission, a structure where one (single) shift spindle is provided with a master arm to operate a transmission via an accumulation mechanism and a clutch lever to operate a clutch. In the accumulation mechanism, the master arm is supported rotatably with respect to the shift spindle. The clutch lever is fixed to the shift spindle. Further, a sub arm is fixed to the shift spindle, and a preload spring exists between the master arm and the sub arm. According to this structure, it is possible to rotate the clutch lever while accumulating a force to operate the transmission and rotating strokes (accumulating) in the master arm with the preload spring between the master arm and the sub arm. Then, when the accumulation sufficient to operate the transmission has been completed in the preload spring (a rotational angle of the shift spindle at this time is also referred to as an “accumulation completion angle”), the clutch is disconnected and the accumulation for the master arm is released, then it is possible to quickly perform gear change.

However, in the transmission in JP-A No. 2001-280493, as the sub arm and the clutch lever are respectively fixed to the shift spindle, at the same time of the rotation of the shift spindle, the sub arm and the clutch lever also start rotating. Accordingly, the accumulation and the clutch operation with the preload spring are approximately simultaneously started.

However, in the transmission in JP-A No. 2001-280493, there is a probability of a disconnection of the clutch before completion of the accumulation in the master arm due to aging of the clutch and the like. In a case where the clutch is disconnected before the accumulation completion angle is established, since rotation strokes necessary for operation of the transmission are insufficient with the opened preload spring, it is necessary to wait for the rotation of the shift spindle to a predetermined angle. In this case, as the clutch-disconnected status is continued for a comparatively long time, the status where the driving force is released is prolonged.

SUMMARY AND OBJECTS OF THE INVENTION

The present invention has an object to provide a vehicle transmission with a master arm to operate a transmission via an accumulation mechanism and a clutch lever to operate a clutch in a single shift spindle, which more reliably realizes clutch disconnection after the completion of accumulation necessary for shift operation.

According to an embodiment of the present invention, a vehicle transmission includes a single shift spindle; a master arm, provided on the shift spindle, that transmits a rotational force of the shift spindle to a shift drum of the transmission to rotate and operate the shift drum; a clutch lever provided on the shift spindle to operate a clutch; and an accumulation mechanism capable of accumulation of the rotational force transmitted from the shift spindle to the master arm. The master arm and the clutch lever are interlocked with each other. The transmission further includes a delay mechanism that delays a disconnection operation of the clutch with the clutch lever until the accumulation is completed between the shift spindle and the clutch.

According to an embodiment of the present invention, the delay mechanism functions as a lost mechanism not to contribute a part of the rotational angle of the shift spindle to the disconnection operation of the clutch with the clutch lever.

According to an embodiment of the present invention, the clutch lever is rotatably supported by the shift spindle with a delay member fixed to the shift spindle. Further, the clutch lever and the delay member have a doweled tooth and a doweled hole linked to each other. Further, the delay mechanism is formed with a gap in a circumferential direction between the doweled tooth and the doweled hole.

According to an embodiment of the present invention, the delay mechanism is formed with backlash in a moving direction in a clutch lifter mechanism that performs disconnection of the clutch by moving with respect to the clutch.

According to an embodiment of the present invention, the shift spindle and the delay member integrally rotate.

According to an embodiment of the present invention, the accumulation mechanism is formed with a coiled spring, and is provided so as to directly cover a peripheral surface of the shift spindle.

According to an embodiment of the present invention, the clutch lever is linked to a clutch lifter cam that lifts the clutch to disconnect or connect it via a guide hole provided in the clutch lifter cam, and the delay mechanism is provided as a backlash hole of the guide hole.

According to an embodiment of the present invention, the clutch lever is linked to a clutch lifter cam that lifts the clutch to disconnect or connect it, and the clutch lifter cam has a plurality of valley-shaped slope plates linked to a clutch lifter plate via a ball-shaped member, further, the delay mechanism is provided as a flat part formed in the valley-shaped slope plate.

According to an embodiment of the present invention, the clutch lever is linked to a clutch lifter cam that lifts the clutch to disconnect or connect it, and the clutch lifter cam is linked to a clutch lifter plate via a ball-shaped member. Further, the clutch lifter plate has an anchor rotation-stopped with respect to the transmission. In addition, the delay mechanism is provided as an elliptic locking hole to lock the anchor.

According to an embodiment of the present invention, the clutch lever is linked with a clutch lifter cam that lifts the clutch to disconnect or connect it with a cam surface provided in the clutch lifter cam, and the delay mechanism is provided as an idle cam of the cam surface.

According to an embodiment of the present invention, the clutch lever is provided as a link mechanism to which a plurality of arm members are linked, and one arm member in the link mechanism has a stopper to limit a rotational angle of other arm member. Further, the delay mechanism is provided as a rotatable range for the respective arm members in the link mechanism.

According to an embodiment of the present invention, as it is possible to complete the accumulation before the clutch disconnection operation, it is possible to more reliably realize clutch disconnection after the completion of the accumulation necessary for shift operation. Accordingly, it is possible to more reliably and quickly perform shift operation after the clutch disconnection.

According to an embodiment of the present invention, the delay mechanism functions as a lost mechanism not to contribute a part of the rotational angle of the shift spindle to the clutch disconnection operation with the clutch lever. Accordingly, it is possible to easily perform the completion of the accumulation before clutch disconnection operation with the lost mechanism.

According to an embodiment of the present invention, the accumulation collar as the clutch lever and the delay member has mutually linked second doweled tooth and second doweled hole. The delay mechanism is formed with gaps between the second doweled tooth and the second doweled hole in a circumferential direction. Accordingly, the delay mechanism has a compact and simple structure.

According to an embodiment of the present invention, the delay mechanism is formed with backlash in a moving direction of the clutch lifter mechanism which performs the clutch disconnection by moving with respect to the clutch. Accordingly, the delay mechanism has a simple structure.

According to an embodiment of the present invention, the shift spindle and the delay member are rotated integrally. Accordingly, when the shift spindle rotates, it is possible to quickly rotate the master arm via the delay member, the accumulation mechanism and the like.

According to an embodiment of the present invention, the accumulation mechanism is formed with a coiled spring, and is provided so as to directly cover the peripheral surface of the shift spindle. Accordingly, the accumulation mechanism has a compact structure.

According to an embodiment of the present invention, the delay mechanism is provided as a backlash hole of the guide hole. Accordingly, it is possible to increase the size of the guide hole (especially it is possible to prolong the guide length). Accordingly, it is possible to easily set and manage the accuracy of a delay function of the delay mechanism.

According to an embodiment of the present invention, the delay mechanism is provided as a flat part formed in a valley-shaped slope plate. Accordingly, it is possible to realize the delay mechanism with a simple structure.

According to an embodiment of the present invention, the clutch lifter plate has an anchor rotation-stopped with respect to the transmission, and the delay mechanism is provided as an elliptic locking hole to lock the anchor. Accordingly, it is possible to realize the delay mechanism with a simple structure.

According to an embodiment of the present invention, the clutch lifter cam is provided with a cam surface, and the delay mechanism is provided as an idle cam of the cam surface. Accordingly, it is possible to realize the delay mechanism with a simple structure.

According to an embodiment of the present invention, the clutch lever is provided as a link mechanism connected with a plurality of arm members, and the delay mechanism is provided as a rotatable range for the respective arm members in the link mechanism. When the delay mechanism is provided on the clutch side, generally, it is necessary to provide a structure to realize a large sized delay in the clutch lifter cam or the like. On the other hand, as the clutch lever is formed with a link mechanism and the delay mechanism is provided as the rotatable range for the respective arm members in the link mechanism, it is possible to set the delay mechanism as a compact structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, a motorcycle1having a clutch-interlock transmission50according to an embodiment of the present invention will be described based onFIGS. 1 to 20.

Note that in the following description, the description of front/rear, left/right and upward/downward directions follows a direction viewed from a rider who rides on the motorcycle unless explicitly stated. Further, in the figures, an arrow FR indicates the frontward direction with respect to the vehicle; an arrow LH, the leftward direction with respect to the vehicle; and an arrow UP, the upward direction with respect to the vehicle.

As shown inFIG. 1, a vehicle body frame2of the motorcycle1has a head pipe3, a main pipe4, a center frame5, a pair of left and right rear pipes6,6, and a pair of left and right back stays7,7. The head pipe3is positioned on the vehicle body front side (FR side). The main pipe4extends diagonally rearwardly and downwardly from the head pipe3. The center frame5extends downwardly from a rear part of the main pipe4while expanding to the left and the right. The pair of left and right rear pipes6,6extend diagonally rearwardly and upwardly from a position in front of the center frame5in the main pipe4, and bend approximately horizontally in the middle, and extends to the rear. The pair of left and right back stays7,7are provided between left and right sides of the center frame5expanding to the left and the right and rear parts of the rear pipes6,6.

A steering shaft8is rotatably pivoted with the head pipe3. A front fork9having a suspension extends on the lower side of the steering shaft8. A front wheel Fw is journaled to a lower end of the front fork9. A handle bar8bextending to the left and the right is attached to an upper part of the steering shaft8.

A rear fork11is journaled to the center frame5via a pivot shaft10at its front end. The rear fork11extends rearwardly. A rear wheel Rw is journaled to a rear end of the rear fork11to oscillate upwardly/downwardly. A shock absorber12is provided between the rear part of the rear fork11and the rear pipe6.

The power unit P, supported with the main pipe4and the center frame5, is suspended in a lower part of the main pipe4. The power unit P has a unit case20, an internal combustion engine21integrally provided with the unit case20, and the transmission50.

An output sprocket13is fitted to an output shaft (as described later, a counter shaft52of the transmission (50)) of the power unit P. The output sprocket13is positioned right in front of the pivot shaft10. A chain15is put between the output sprocket13and a driven sprocket14on the rear wheel Rw side.

A fuel tank16is installed on slopes of the rear pipes6,6. A seat17covers the fuel tank16and rear-side horizontal parts of the rear pipes6,6. A vehicle body cover18covers approximately the entire vehicle body frame2. A rear anchor of a main stand19is journaled to a lower end of the center frame5.

The power unit P is mainly formed by providing the internal combustion engine21on the front side of the unit case20and the transmission50on the rear side. The internal combustion engine21is an air-cooled single-cylinder 4-stroke internal combustion engine. The transmission50is a shift gear engagement mechanism with a 4-stage speed change.

As shown inFIGS. 2 and 3, the internal combustion engine21has a unit case20that functions as a crankcase. A crankshaft22is oriented in a vehicle width direction (in a left and right direction), and rotatably journaled to the unit case20. A cylinder block23and a cylinder head24are integrally fastened to a front part of the unit case20. The cylinder block23and the cylinder head24project while they are forward-tilted approximately horizontally. A cylinder head cover25is put on the cylinder head24.

An intake pipe26extends upward from an upper surface of the approximately-horizontally projected cylinder head24. The intake pipe26is connected to an air cleaner28. The air cleaner28is suspended from a front part of the main pipe4via a throttle body27.

An exhaust pipe30extends downwardly from a lower surface of the cylinder head24. The downward-extending exhaust pipe30immediately bends horizontally, then extends rearwardly to the diagonally right side, passes through a lower surface of a part of the unit case20, rightwardly of the vehicle body, then directly extends rearwardly, and is connected to a right side muffler31on the right side of the rear wheel Rw.

A step bar33is fixed to the lower surface of the unit case20. In the step bar33, both sides of a center horizontal part33aoriented in the vehicle width direction bend upwardly to form left and right arms33b,33b. Further, the step bar33bends outwardly in the vehicle width direction, to form left and right horizontal steps33c,33c. The center horizontal part33ais fixed to the lower surface of the unit case20.

The left and right arms33b,33bof the step bar33extend diagonally to the front and upwardly from the center horizontal part33aalong left and right side surfaces of the power unit P. Step members34,34are attached to the left and right horizontal steps33c,33cbending outwardly at upper ends of the left and right arms33b,33b. The step member34has a long rectangular parallelepiped shape in the longitudinal direction. Note that the right side of the center horizontal part33abends across the exhaust pipe30extending in the longitudinal direction from a position under the exhaust pipe30.

As shown inFIG. 4, the unit case20is divided in a left unit case20L and a right unit case20R. By integrating the left unit case20L and the right unit case20R, inner space is formed. The inner space has a crankcase20con the front side and a transmission case20mon the rear side. In the crankcase20c, the crankshaft22is rotatably provided with the left and right unit cases20L,20R via the main bearings22b,22b. A transmission mechanism such as the transmission50is accommodated in the transmission case20m.

In a cylinder liner23cintegrally molded in the cylinder block23, a piston35slides reciprocally. The piston35and the crankshaft22, connected with a connecting rod36, form a crank mechanism.

A drive sprocket40of a valve drive system is fitted to a left-side crankshaft22L protruding from the left unit case20L to the left side in the vicinity of a main bearing22b. An AC generator41is provided at the left end of the left-side crankshaft22L. A driven gear42of a start mechanism is fitted between the drive sprocket40and the AC generator41.

The AC generator41projecting on the left side of the left unit case20L is covered with the ACG cover43as a left-side unit case cover, from the left side.

On the other hand, a centrifugal takeoff clutch45is provided on a right-side crankshaft22R protruding from the right unit case20R to the right side. In the takeoff clutch45, a clutch outer45ois supported rotatably around a clutch inner45iintegrally fixed with the right-side crankshaft22R. When the number of revolutions (number of engine revolutions) of the crankshaft22exceeds a predetermined number of revolutions, a clutch shoe of the clutch inner45iis pressed against the clutch outer45o, which transmits the power.

Note that a one-way clutch44is provided between the clutch outer45oand the clutch inner45i. With this arrangement, an engine brake is directly effective without the takeoff clutch45.

In the right-side crankshaft22R, a primary drive gear46, which is in contact with the left side of the clutch outer45oand rotates along with the clutch outer45o, is rotatably journaled to the right-side crankshaft22R.

As shown inFIG. 4, in the transmission case20mas inner space on the rear side of the unit case20, a main shaft51extends in parallel with the crankshaft22in a rear position of the crankshaft22, and rotatably installed on the left and right unit cases20L,20R via bearings51b,51b. In a further rear position from the main shaft51, the counter shaft52extends in parallel with the main shaft51, and rotatably installed on the left and right unit cases20L and20R via bearings52b,52b. The crankshaft22, the main shaft51and the counter shaft52, in this order, are provided in linearly arrayed state from the front.

The transmission50is formed with always mutually engaged first to fourth shift position gears of a gear array51G arranged on the main shaft51and a gear array52G arranged on the counter shaft52. One of the gear array51G and the gear array52G rotates along with the shaft, and the other freely rotates with respect to the shaft.

A gearshift position at any of the first to fourth shift position or a neutral state is established by combination of movement of a serration-engaged shifter gear51gsof the gear array51G on the main shaft51in the axial direction to be disconnected from adjacent gear and movement of a serration-engaged shifter gear52gsof the gear array52G on the counter shaft52in the axial direction to be disconnected from an adjacent gear.

The main shaft51protrudes from the right unit case20R to the right side. A clutch60is provided on the projecting part of the main shaft51. A clutch outer61of the clutch60is relatively rotatably journaled to the main shaft51via a sleeve59. A primary driven gear47is attached to the clutch outer61via a buffer member48. A primary drive gear46decelerates the primary driven gear47engaged with the drive gear and rotates along with the clutch outer61.

A clutch inner62is integrally fitted to a right end of the main shaft51. A plurality of drive friction plates63serration-engaged with an outer periphery of a peripheral wall of the clutch inner62and driven friction plates64serration-engaged with an inner periphery of the peripheral wall of the clutch outer61are alternately arrayed in the axial direction. The pressure plate65, holding the drive friction plates63and the driven friction plates64between the pressure plate65and a disc outer periphery of the clutch inner62, is slidably supported with the clutch inner62in the axial direction.

As shown inFIGS. 4 and 7, the pressure plate65that is slidable in the axial direction is positioned on the inner side from the clutch inner62in the axial direction inside the clutch outer61. In the disc member of the clutch inner62, a plurality of support bosses65bprojecting from the pressure plate65are inserted through the plurality of through holes formed in a circumferential direction. At a leading end of the support boss65b, a ring-shaped release flange66is fastened with a bolt67.

A clutch spring68which is a disc spring is provided between the release flange66and the clutch inner62. With the clutch spring68, the pressure plate65is pressed to the right integrally with the release flange66. The pressure plate65holds the drive friction plates63and the driven friction plates64between the pressure plate65and the clutch inner62. With this arrangement, the clutch60is maintained in a connected status, and the rotation of the clutch outer61is transmitted to the clutch inner62and further to the main shaft51.

When the release flange66is pushed to the left, and the pressure plate65moves to the left against the clutch spring68, the interval between the pressure plate65and the clutch inner62is increased. With this arrangement, the holding of the drive friction plates63and the driven friction plates64is loosened, and the connected status of the clutch60is released.

The clutch60is formed with a slipper clutch having a back torque limiter mechanism (also called a back torque reduction mechanism). The back torque limiter mechanism is a mechanism to, when excessive torque (back torque) acts on the clutch60in an opposite direction to a forward direction power transmission, return the clutch60from the connected status to a connection-loosened status (clutch half engaged status). As the back torque limiter mechanism, a mechanism having a well-known structure can be used. According to the back torque limiter mechanism, it is possible to reduce shock due to back torque upon shift down.

The rotation of the crankshaft22of the internal combustion engine21is transmitted through the takeoff clutch45and the clutch60to the main shaft51of the transmission50.

The takeoff clutch45provided at the right end of the right-side crankshaft22R and the clutch60provided at the right end of the main shaft51are covered with a right-side unit case cover49from the right side.

Note that the output sprocket13fitted to the end of the counter shaft52, inserted through the left unit case20L leftward, is covered with a sprocket cover53, except a rear part where the chain15extends, from the left side.

As shown inFIGS. 2,5and6, the shift spindle55is provided diagonally low and to the rear of the crankshaft22and diagonally low and to the front of the counter shaft52and the main shaft51. As shown inFIG. 7, the shift spindle55is inserted through the left and right unit cases20L and20R in the left and right directions. Further, the right side part is inserted through a bearing boss49aof the right-side unit case cover49and rotatably journaled.

The shift spindle55is provided in a lower part of the unit case20, and positioned below a step member34in a side view shown inFIG. 2.

The rotation of the shift spindle55drives a clutch operation mechanism70and a shift operation mechanism80. The clutch operation mechanism70operates the clutch60to perform disconnection and connection of the clutch60. The shift operation mechanism80operates the transmission50to shift the shift position of the transmission50.

The clutch operation mechanism70will be described based onFIGS. 4 and 7.

As shown inFIGS. 4 and 7, in the shift spindle55, the clutch lever72is oscillatably supported in the vicinity of the bearing boss49aof the right-side unit case cover49. The structure and operation of the oscillation of the clutch lever72in accordance with the rotation of the shift spindle55will be described in detail later.

On the other hand, as shown inFIGS. 4,7and8, an outer ring of the ball bearing75is fitted to an inner peripheral surface of the ring-shaped release flange66of the clutch60. A rear anchor intrusion member74aat the rotational center of the operation lever74, or clutch lifter cam74, is fit-inserted and fixed to an inner ring of the ball bearing75. The clutch lifter cam74is a cam to lift the clutch60for disconnection or connection. The rear anchor intrusion member74aintrudes in two steps of leading end small diameter part and large diameter part. The leading end small diameter part is fitted in the inner ring of the ball bearing75. A roller73projected from the leading end of the clutch lever72is engaged with a rotating engagement cam hole74cof the operation lever or clutch lifter74.

The clutch adjustment bolt76is fixed to an extended part of the main shaft51of the right-side unit case cover49. The clutch adjustment bolt76is inserted in the large diameter part of the rear anchor intrusion member74aof the operation lever74from the right side, and supports the operation lever74rotatably and slidably in the axial direction. In a rear anchor disc member74baround the rear anchor intrusion member74aof the operation lever74, the clutch lifter plate77, which is facing on the right side, and which is rotation-regulated with the right-side unit case cover49, is supported with the clutch adjustment bolt76. The operation lever74is relatively rotatable with respect to the rotation-regulated clutch lifter plate77, and is movable in the axial direction. The operation lever74is pressed to the right by operation of the spring force of the clutch spring68of the clutch60via the ball bearing75.

In other words, the clutch adjustment bolt76is a part of the right-side unit case cover49and is fixed to an extended part of the main shaft51. The clutch adjustment bolt76is inserted in the large diameter part of the rear anchor intrusion member74aof the clutch lifter cam74from the right side, and supports the clutch lifter cam74rotatably and slidably in the axial direction. In a rear anchor disc member74baround the rear anchor intrusion member74aof the clutch lifter cam74, the clutch lifter plate77, opposite on the right side, and rotation-regulated with the right-side unit case cover49, is supported with the clutch adjustment bolt76. As shown inFIGS. 7 and 8, the clutch lifter plate77has an anchor77arotation-stopped (rotation-regulated) with respect to the transmission (more particularly, the locking hole49bof the right-side unit case cover49). The locking hole49bis provided inside the right-side unit case cover49. The clutch lifter cam74is relatively rotatable to the clutch lifter plate77rotation-regulated with the anchor77a, and movable in the axial direction. The clutch lifter cam74is pressed to the right by operation of the spring force of the clutch spring68of the clutch60via the ball bearing75.

It is possible to increase/decrease the interval between opposed surfaces of the clutch lifter plate77and the rear anchor disc member74bof the operation lever74by changing a relative position (engagement position) between a female screw formed in the rotational shaft part of the clutch lifter plate77and a male screw of the clutch adjustment bolt76b. With this arrangement, it is possible to increase/decrease the backlash in the moving direction in a clutch lifter mechanism74to79.

Groove lines74v,77vare formed in three positions in a radial pattern in the circumferential direction in mutually opposed surfaces of the rear anchor disc member74bof the operation lever74and the clutch lifter plate77. Three release balls79held rollably with a retainer78exist between the rear anchor disc member74band the clutch lifter plate77pressed with the clutch spring68between the rear anchor disc member74band the clutch lifter plate77.

When the clutch60is in the connected status, the three groove lines74v,77vin the opposed surfaces of the rear anchor disc member74band the clutch lifter plate77are opposite to each other. The three release balls79respectively fall in the mutually opposed groove lines74v,77v.

Then, when the shift spindle55rotates upon transmission, the clutch lever72oscillates, and the operation lever74rotates via engagement between the roller73and the engagement cam hole74c. With this arrangement, the groove line74vof the rear anchor disc member74bof the operation lever74rotates relatively to the groove line77vof the clutch lifter plate77.

Thereafter, the release balls79held between the rear anchor disc member74bof the operation lever74and the clutch lifter plate77roll, while smoothly rising on the slopes of the groove lines74v,77v, to press and move the operation lever74to the clutch60side (left side). Accordingly, the release flange66moves to the left against the pressing force of the clutch spring68via the ball bearing75, and the pressure plate65moves to the left. With this arrangement, in the clutch60, the connected status is released and disconnected.

As described above, the clutch lifter mechanisms74to79to perform disconnection of the clutch60by moving with respect to the clutch60is formed with the operation lever74, the ball bearing75, the clutch adjustment bolt76, the clutch lifter plate77, the retainer78, the release balls79and the like.

As shown inFIG. 7, the clutch operation mechanism70is formed on the outer side (right side) of the clutch60and on the inner side (left side) of the right-side unit case cover49. On the other hand, the shift operation mechanism80to operate the transmission50to shift the shift position is formed on the inner side (left side) of the clutch60.

The shift forks91,92move the shifter gear51gson the main shaft51and the shifter gear52gson the counter shaft52of the transmission50in the axial direction. As shown inFIG. 3, the shift forks91,92, in an upper position between the main shaft51and the counter shaft52, operate by rotation of a shift drum90rotatably provided between the left and right unit cases20L,20R.

As shown inFIG. 7, the shift forks91,92are rotatably journaled relatively to the shift drum90at the rear anchor. In the shift forks91,92, engagement pins91p,92pprojecting towards the rear anchor are slidably engaged with a predetermined-shaped shift grooves formed in an outer peripheral surface of the shift drum90. The respective leading ends of the shift forks91,92are respectively engaged with the shifter gears51gs,52gs. Accordingly, when the shift drum90rotates, the shift forks91,92move in the axial direction via the engagement pins91p,92pguided with the shift groove and moved in the axial direction, to shift the shift position of the transmission50.

As shown inFIGS. 6 and 7, the right end of the shift drum90is slidably supported with the right unit case20R on the outer peripheral surface. A right-side wall90rof the shift drum90is exposed to the right side from a bearing opening of the right unit case20R. A pentalpha-shaped star plate93is fixed to a central boss of the right-side wall90rwith a bolt94. Five locking pins95are built around the bolt94of the right-side wall90r. The locking pins95are provided between the right-side wall90rand the star plate93.

As shown inFIG. 6, the stopper arm96is journaled to the pivot96p, and oscillated and pressed with the spring98. The locking roller97is journaled to the leading end of the stopper arm96. The locking roller97is pressed against the outer peripheral surface of the star plate93having five peaks in a radial pattern. The shift drum90is positioned in a predetermined position with the locking roller97fitted and stabled among the peaks of the star plate93.

A mechanism to rotate by operating the shift drum90to the locking pins95is formed along the right side surface of the right unit case20R. As shown inFIGS. 6,7and9to11, the gear shift arm81is externally fitted in the sleeve81drelative-rotatably (oscillatably) to the shift spindle55. The master arm83is externally fitted to relative-rotatably (oscillatably) to the sleeve81dof the gear shift arm81.

The master arm83has a fan-shaped oscillation rear anchor83aand an arm83bextending from an upper position of the oscillation rear anchor83a. A regulation opening83his formed in the oscillation rear anchor83aoverlapped with the gear shift arm81in a side view. A spring locking piece83fis formed to bend to the left on a side on the oscillation center side of the regulation opening83h. The gear shift arm81has a spring locking piece81fformed to bend to the left. The spring locking piece81fis inserted through the regulation opening83hof the master arm83.

The regulation pin84projects to the right from the right unit case20R is inserted through the regulation opening83hof the oscillation rear anchor83aof the master arm83. The leading end of the regulation pin84is in the vicinity of the gear shift arm81. Then, the both ends of the shift return spring85coiled around the outer periphery of the sleeve81dextend so as to hold the regulation pin84. The spring locking piece81fof the gear shift arm81and the spring locking piece83fof the master arm83have a width the same as the diameter of the regulation pin84, and held, along with the regulation pin84, between the both ends of the shift return spring85.

In the vicinity of an upper end of the arm83bextending above the master arm83, a locking bar87, which is connected at a front end with the connecting pin86, extends to the rear. The locking bar87extends to the rear beneath the five locking pins95built between the shift drum90and the star plate93.

A tension spring88is put between the upper end of the arm83bof the master arm83and the locking bar87. The tension spring88oscillates the locking bar87, which extends to the rear and upwardly and presses it, and brings the locking pins95positioned at a lower side to abut on the locking bar87. At the upper-side edge of the locking bar87, the locking claws87f,87r, longitudinally separated, projects upwardly.

As indicated with a solid line inFIG. 6, when power is not applied to the shift spindle55, both ends of the shift return spring85hold the regulation pin84therebetween, and at the same time hold the spring locking piece81fof the gear shift arm81and the spring locking piece83fof the master arm83. Further, the gear shift arm81and the master awl83are positioned such that the shift spindle55, the spring locking piece83f, the regulation pin84and the spring locking piece81fare arrayed in line. At this time, the locking bar87brings two locking pins95,95positioned on the lower side to abut on an upper-side edge between the front and rear locking claws87f,87r, by a pressing force of the tension spring88.

When the power is applied to the shift spindle55and it rotates, the gear shift arm81oscillates against the shift return spring85. When the spring locking piece81facts on the master arm83, then in the master arm83, an arm83bextending upwardly oscillates in the front and rear directions. Then the locking bar87connected to the master arm83with the connecting pin86moves in the front and in the rear directions, and one of the locking claws87f,87rin front and rear of the locking bar87is locked with the locking pin95, to rotate the shift drum90along with the star plate93.

When the locking roller97at the leading end of the stopper arm96is over the top of one peak of the star plate93by the rotation of the star plate93, the star plate93rotates at a predetermined angle along with the shift drum90with the pressing force of the locking roller97until the locking roller97is settled on the valley.

Accordingly, the movement of the locking bar87in the front and rear directions with the oscillation of the master arm83may be stopped when the locking claws87f,87rare locked with the locking pins95and the locking roller97is over the top of the peak of the star plate93. Thereafter, the master arm83, the gear shift arm81, and the shift spindle55may be returned to the initial statuses.

The shift forks91,92, guided with the shift grooves and moved in the axial direction by the rotation of the shift drum90at the predetermined angle, move the shifter gears51gs,52gsof the transmission50, to shift the shift position.

Note that as described later, as the connection of the clutch60is released before the shifting of the shift position in the transmission50, the shift position is smoothly shifted.

The shift spindle55which drives both of the above-described shift operation mechanism80and the clutch operation mechanism70rotates by the drive of the shift motor100transmitted via the shift power transmission mechanism110. The shift power transmission mechanism110will be described below.

As shown inFIG. 2, the shift spindle55is provided in a position in a diagonally lower and to the rear of the crankshaft22and diagonally lower and to the front of the counter shaft52and the main shaft51, and is inserted through the left and right unit cases20L,20R outward in the left and right directions.

As shown inFIG. 7, the right side part of the shift spindle55inserted through the right unit case20R is further inserted through the bearing boss49aof the right-side unit case cover49. The right end of the shift spindle55inserted through the bearing boss49aof the right-side unit case cover49is provided with an angle sensor121to detect a rotational angle of the right end of the shift spindle55.

The left side of the shift spindle55inserted through the left unit case20L is provided with the shift power transmission mechanism110. The shift power transmission mechanism110is accommodated in a shift power transmission case102having a longitudinally long and horizontally narrow flat shape.

The shift power transmission case102is formed by combining the left-side shift power transmission case102L and the right-side shift power transmission case102R. The shift spindle55is inserted in a front end of the shift power transmission case102and extends to the rear. Then, as shown inFIG. 2, the shift power transmission case102is provided below the ACG cover43as a unit case cover to cover the AG generator41on the side of the crankshaft22and the sprocket cover53to cover the output sprocket13on the side of the counter shaft52.

In the shift power transmission mechanism110, when the shift motor100is driven and a drive gear shaft100arotates, the rotation is decelerated via a deceleration gear111and transmitted to the rotation of a crank gear112. The rotation of the crank gear112oscillates an oscillating arm116via a crank pin114p, to rotate the shift spindle55integral with the oscillating arm116. Then, when the shift spindle55rotates, the clutch operation mechanism70operates the clutch60to perform clutch disconnection/connection, and the transmission operation mechanism80operates the transmission50to shift the shift position.

Next, the structure of a delay mechanism and a lost mechanism of the transmission50will be described with reference toFIGS. 9 to 20.

As shown inFIGS. 9 to 12, the transmission50mainly has, as a structure regarding the delay mechanism and the lost mechanism, a single shift spindle55, the master arm83, the gear shift arm81, the shift return spring85, the preload stopper collar56, the accumulation spring57, the accumulation collar71and the clutch lever72.

In the transmission50, the accumulation spring57functions as an accumulation mechanism capable of accumulating a rotational force transmitted from the shift spindle55to the master arm83. A delay mechanism to delay a disconnection operation of the clutch60with the clutch lever72until the accumulation of the rotational force with the accumulation spring57is completed is provided between the shift spindle55and the clutch60. This delay mechanism functions as a lost mechanism not to contribute a part of the rotational angle of the shift spindle55to the disconnection operation of the clutch60with the clutch lever72.

As shown inFIG. 13, the shift spindle55has a thrust member55aprovided at a central part in the axial direction, a serration member55badjacent to the thrust member55ain the axial direction and provided on the left side, and a serration member55cprovided on the opposite side (right side) to the serration member55baway from the thrust member55awith an interval, holding the thrust member55atherebetween.

As shown inFIGS. 9 to 12and14(b), the master arm83is oscillatably supported with the shift spindle55. The master arm83transmits the rotational force of the shift spindle55to the shift drum90to operate the shift drum90by rotating it as described above. The master arm83has the oscillation rear anchor83a, the arm83b, the regulation opening83h, the spring locking piece83f, a sleeve83d, and an insertion hole83c.

The oscillation rear anchor83ahas a fan shape which spreads toward the leading end. The arm83bextends from an upper part of the oscillation rear anchor83a. The regulation opening83his formed in a position overlapped with the gear shift arm81in a side view in the regulation opening83h. The spring locking piece83fis formed to bend (protrude) to the left on the side of the regulation opening83hon the oscillation center side. The sleeve83dis provided so as to extend to the oscillation center of the master arm83along the axial direction and to protrude in the projecting direction of the spring locking piece83f. The insertion hole83cis provided so as to be inserted through the inside of the sleeve83dalong the axial direction of the master arm83. In the insertion hole83c, the sleeve81d(to be described later) of the gear shift arm81is inserted therethrough.

The locking bar87is as described above.

As shown inFIGS. 9 to 12and15(a) and15(b), the gear shift arm81abuts on the master arm83, and is rotatably supported with the shift spindle55. The gear shift arm81has an oscillating rear anchor81e, the spring locking piece81f, a gear shift arm-side locking member81a, a first doweled hole81b, an insertion hole81cand the sleeve81d.

The oscillating rear anchor81ehas a shape which shrinks toward the leading end side. The oscillating rear anchor81eis provided adjacent to the oscillation rear anchor83aof the master arm83on the right side. The spring locking piece81fis formed by bending (extending) the leading end side of the gear shift arm81to the left. The spring locking piece81fis inserted through the regulation opening83hof the master arm83from the right side to the left side.

The sleeve81dis provided so as to extend to the oscillation center of the gear shift arm81along the axial direction and protrudes in the projection direction of the spring locking piece81f. The insertion hole81cis provided so as to be inserted through the inside of the sleeve81dalong the axial direction of the gear shift arm81. The shift spindle55is inserted through the insertion hole81c.

The gear shift arm-side locking member81aprotrudes to the right side to a peripheral part in the oscillating rear anchor81eaway from the insertion hole81cin the radial direction. The gear shift arm-side locking member81ais, when the gear shift arm81is viewed from the right side to the left side in the axial direction, provided in the left lower region, and extends in a circular-arc shape in the circumferential direction. The first doweled hole81bis linked to a first doweled tooth56a(to be described later) of the preload stopper collar56. The first doweled hole81bis formed as a concavity to the left side in a part adjacent to the insertion hole81cin the oscillating rear anchor81e. The first doweled hole81bis, when the gear shift arm81is viewed from the right side to the left side in the axial direction, provided in a right lower region, extends in a circular-arc shape in the circumferential direction, and its central angle is about 60°.

The preload stopper collar56rotates integrally with the shift spindle55by engagement with the serration member55b. As shown inFIGS. 9 to 12and16(a) and16(b), the preload stopper collar56has a collar main body56b, the first doweled tooth56aand an inner peripheral serration member56c. The collar main body56bhas an approximately cylindrical shape. The first doweled tooth56aprotrudes from a left end surface of the collar main body56bto the left side. The first doweled tooth56aextends in a circular-arc shape in the circumferential direction, and its central angle is about 45°.

The central angle of the first doweled tooth56ais smaller than the central angle of the first doweled hole81b. More specifically, there is a circular-arc backlash (gap, play) between the first doweled tooth56aand the first doweled hole81bin the circumferential direction.

The inner peripheral serration member56cis provided on the inner peripheral member of the collar main body56b, and is serration-engaged with the serration member55bof the shift spindle55. In a status where the inner peripheral serration member56cis serration-engaged with the serration member55bof the shift spindle55, the right end surface of the collar main body56babuts on the thrust member55aof the shift spindle55.

The accumulation spring57presses the master arm83in an oscillating direction while accumulating the rotational force of the shift spindle55between the shift spindle55and the master arm83. The phrase, “accumulating the rotational force” arbitrarily includes “accumulating the rotational angle (turning angle)”. The accumulation spring57is capable of accumulating the rotational force transmitted from the shift spindle55to the master arm83.

As shown inFIGS. 9,11and17, the accumulation spring57has a coiled shape, and is provided so as to directly cover a peripheral surface of the shift spindle55. The “directly cover” means that no other member exists between the accumulation spring57as an accumulation mechanism and the shift spindle55.

In the accumulation spring57, its one end57ais locked with the gear shift arm-side locking member81a, and its other end57bis locked with an accumulation collar-side locking member71aof the accumulation collar71. The accumulation spring57gives a pressing force to rotate shift drum90to the shift up side.

As described above, the gear shift arm-side locking member81aand the accumulation collar-side locking member71aare formed with a boss extending in parallel with the axial direction of the shift spindle55.

As shown inFIGS. 9,11and18(a) and18(b), the accumulation collar71is provided on the side of the clutch lever72with respect to the gear shift arm81, and fixed to the shift spindle55and integrally rotated (pivoted).

The accumulation collar71has a collar main body71d, the accumulation collar-side locking member71a, a second doweled tooth71band an inner peripheral serration member71c.

The collar main body71dhas an approximately cylindrical shape. The accumulation collar-side locking member71aprotrudes from a left end surface of the collar main body71dto the left side. The accumulation collar-side locking member71aextends in a circular-arc shape in the circumferential direction, and its central angle is about 60°.

The second doweled tooth71bprotrudes from the right end surface of the collar main body71dto the right side, and is linked to the second doweled hole72b(to be described later) of the clutch lever72. The second doweled tooth71bextends in a circular-arc shape in the circumferential direction, and its central angle is about 30°. The second doweled tooth71bis provided in three positions away from each other in the circumferential direction. The angle between adjacent second doweled teeth71bin the circumferential direction is about 90°. When the accumulation collar71is viewed in the axial direction, the accumulation collar-side locking member71aand the three second doweled tooth71bare provided in non-overlapped positions.

The inner peripheral serration member71cis provided on the inner peripheral part of the collar main body71d, and is serration-engaged with the serration member55cof the shift spindle55.

Note that in the present embodiment, the accumulation collar71is integrally formed, however, it is not limited to this arrangement. For example, the accumulation collar71, in a position indicated with an alternate long and two short dashes line D inFIG. 9, may be formed with separate body members divided in the axial direction on the side of the accumulation collar-side locking member71aand the side of the second doweled tooth71b.

As shown inFIGS. 9,19(a),19(b) and20(a) and20(b), the clutch lever72is rotatably supported with the shift spindle55, and operates the clutch60. The clutch lever72has a rear anchor72d, a lever72e, a wall72a, the second doweled hole72band an insertion hole72c.

The lever72eextends from the rear anchor72d. Three second doweled holes72band three walls72aare provided on the left end side of the rear anchor72d.

The three second doweled hole72bare provided in positions corresponding to the three second doweled tooth71bin the accumulation collar71. The second doweled tooth71bis inserted in the second doweled hole72b. That is, the second doweled tooth71band the second doweled hole72bare linked to each other.

The second doweled hole72bextends in a circular-arc shape in the circumferential direction, and its central angle is about 40° which is wider than the central angle of the second doweled tooth71b. More specifically, there is backlash (gap, play) in a circular-arc shape between the second doweled tooth71band the second doweled hole72bin the circumferential direction. The above-described delay mechanism is formed with this backlash (gap, play) in the circumferential direction.

The wall72ais provided between adjacent second doweled holes72bin the circumferential direction.

The insertion hole72cis provided to be inserted through the inside of the rear anchor72dalong the axial direction of the clutch lever72. The shift spindle55is inserted through the insertion hole72c.

Further, as shown inFIGS. 7 and 9, the gear shift arm-side locking member81aand the accumulation collar-side locking member71aare provided on the opposite side to the clutch60with respect to the axial direction of the shift spindle55. The clutch lever72and the master arm83are provided opposite to each other in the axial direction of the shift spindle55, with the clutch60therebetween. In shift operation, the master arm83and the clutch lever72are interlocked with each other. The details of the interlocked operation will be described later.

Next, the interlocked operation between the master arm83and the clutch lever72in the shift operation with the transmission50will be described with reference toFIGS. 21(a) to27.

In this example, the shift operation upon shift up will be described.FIGS. 21(a) and21(b) show a status before the start of the shift operation. It is a status corresponding to the “start” inFIG. 27.

Note thatFIG. 27shows changes of the shift spindle55angle (Ang), the accumulation spring57angle (Ang), the clutch lift amount, the shift drum90angle (Ang) accompanying the progress of the shift operation and their relation.

As shown inFIG. 21(a), before the start of the shift operation, a gap (backlash) in a shift up direction SU exists between the spring locking piece81fof the gear shift arm81and regulation opening83hof the master arm83. There is a gap (backlash) in the shift up direction SU between the first doweled tooth56aof the preload stopper collar56and the first doweled hole81bof the gear shift arm81. There is no gap (backlash) in the shift up direction SU between the one end57aof the accumulation spring57and the gear shift arm-side locking member81aof the gear shift arm81. Note that the shift up direction SU is a clockwise direction inFIGS. 21(a) to26(b).

Further, as shown inFIG. 21(b), there is a gap (backlash) in the shift up direction SU between the second doweled tooth71bof the accumulation collar71and the second doweled hole72bof the clutch lever72. There is no gap (backlash) in the shift up direction SU between the accumulation collar-side locking member71aof the accumulation collar71and the other end57bof the accumulation spring57.

When the rotation of the shift spindle55starts from the status before the start of the shift operation shown inFIG. 21, the status becomes that shown inFIGS. 22(a) and22(b).FIGS. 22(a) and22(b) show a status corresponding to [1] inFIG. 27.

When the shift spindle55rotates, the accumulation collar71integrated with the shift spindle also rotates. In the status before the start of the shift operation shown inFIGS. 21(a) and21(b), the accumulation spring57abuts on the accumulation collar71and the gear shift arm81. Accordingly, in the status shown inFIGS. 22(a) and22(b), when the accumulation collar71rotates, the accumulation spring57which abuts on the accumulation collar71also integrally rotates, and immediately the gear shift arm81which abuts on the accumulation spring57also rotates.

As shown inFIG. 22(a), the gear shift arm81rotates in the shift up direction SU, the spring locking piece81fabuts on the regulation opening83hof the master arm83. Further, the preload stopper collar56(integrated with the shift spindle55) rotates in the shift up direction SU, the first doweled tooth56aof the preload stopper collar56moves inside the first doweled hole81bof the gear shift arm81in the circumferential direction. As shown inFIG. 22(b), the accumulation collar71(integrated with the shift spindle55) rotates in the shift up direction SU, and further, causes the accumulation spring57to rotate in the shift up direction SU via the accumulation collar-side locking member71aand the other end57b.

It is arranged such that the gear shift arm81does not rotate when the clutch60is in the connected status and the drive force is generated. That is, the gear shift arm-side locking member81adoes not move. Accordingly, accumulation is started in the accumulation spring57where the one end57ais locked with the gear shift arm-side locking member81a.

Note that inFIG. 22(a), as the rotational angle of the preload stopper collar56is minute, it almost does not appear. InFIG. 22(b), as the rotational angle of the accumulation collar71is minute, it almost does not appear.

When the rotation of the shift spindle55progresses from the status shown inFIGS. 22(a) and22(b), the status is as shown inFIGS. 23(a) and22(b).FIGS. 23(a) and23(b) correspond to a status between [1] and [2] inFIG. 27.

As shown inFIG. 23(a), the preload stopper collar56further rotates in the shift up direction SU from the position shown inFIG. 22(a), and the first doweled tooth56aof the preload stopper collar56further moves in the circumferential direction inside the first doweled hole81bof the gear shift arm81from the position shown inFIG. 22(a). As a result, the accumulation progresses in the accumulation spring57.

Further, as shown inFIG. 23(b), the second doweled tooth71bof the accumulation collar71moves in the circumferential direction until there is no gap (backlash) with respect to the second doweled hole72bof the clutch lever72.

When the rotation of the shift spindle55progresses from the status shown in FIGS.23(a) and23(b), the status is as shown inFIGS. 24(a) and24(b).FIGS. 24(a) and24(b) correspond to a status between [2] and [3] inFIG. 27.

As shown inFIG. 24(a), the preload stopper collar56further rotates in the shift up direction SU from the position shown inFIG. 23(a), and the first doweled tooth56aof the preload stopper collar56further moves in the circumferential direction inside the first doweled hole81bof the gear shift arm81from the position shown inFIG. 23(a). As a result, the accumulation progresses in the accumulation spring57, thus the accumulation in a sufficient amount to rotate master arm83is completed.

Further, as shown inFIG. 24(b), when there is no gap (backlash) with respect to the second doweled hole72bof the clutch lever72, the rotation of the clutch lever72is started, and as a result, disconnection (clutch lift) of the clutch60is started via the roller73, the operation lever74and the like.

When the rotation of the shift spindle55progresses from the status shown inFIGS. 24(a) and24(b), the status is as shown inFIGS. 25(a) and25(b).FIGS. 25(a) and25(b) correspond to [3] inFIG. 27.

As shown inFIG. 25(a), the preload stopper collar56further rotates in the shift up direction SU from the position shown inFIG. 24(a), and the first doweled tooth56aof the preload stopper collar56further moves in the circumferential direction inside the first doweled hole81bof the gear shift arm81from the position shown inFIG. 24(a). As a result, the accumulation in the accumulation spring57progresses until there is no gap (backlash) between the first doweled tooth56aand the first doweled hole81b, and the accumulation in a sufficient amount to rotate the master arm83is performed.

Further, when the clutch60is sufficiently disconnected, the drive force is reduced to a released status. As a result, the rotation of the shift drum90and the rotation of the gear shift arm81become possible.

When the rotation of the shift spindle55progresses from the status shown in FIGS.25(a) and25(b), the status is as shown inFIGS. 26(a) and26(b).FIGS. 26(a) and26(b) correspond to a status between [3] and [4] inFIG. 27.

In the status where the drive force is released, the accumulation in the accumulation spring57is released, and with the accumulation, the master arm83immediately rotates. With the rotation of the master arm83, the shift drum90rotates, and shift up is performed. When the rotational angle of the shift drum90exceeds a predetermined reverse start threshold value, the shift spindle55starts reverse (starts rotation in a shift down direction). Further, the rotation of the master arm83stops when the regulation pin84abuts on the regulation opening83h.

As described above, the delay mechanism delays the disconnection operation of the clutch60with the clutch lever72until the accumulation in the accumulation spring57is completed. Further, the delay mechanism functions as a lost mechanism not to contribute a part of the rotational angle of the shift spindle55to the disconnection operation in the clutch60with the clutch lever72.

Further, by changing the relative position between the clutch lifter plate77and the clutch adjustment bolt76, it is possible to increase and decrease the interval between opposed surfaces of the clutch lifter plate77and the rear anchor disc member74bof the operation lever74. With this arrangement, it is possible to increase and decrease the backlash in the moving direction in the clutch lifter mechanisms74to79. For example, when the backlash is large, the moving amount of the clutch lifter mechanisms74to79required to disconnect the clutch60becomes larger in comparison with a case where the backlash is small. By utilizing this relation, the delay mechanism may be arranged in accordance with backlash in the moving direction in the clutch lifter mechanisms74to79to perform disconnection of the clutch60by moving with respect to the clutch60.

According to the transmission50in the present embodiment, for example, following advantages are obtained.

The transmission50in the present embodiment has the master arm83which transmits the rotational force of the shift spindle55to the shift drum90so as to rotate and operate the shift drum90, the clutch lever72to operate the clutch60, the accumulation spring57as an accumulation mechanism capable of accumulating the rotational force transmitted from the shift spindle55to the master arm83, and the delay mechanism to delay the disconnection operation of the clutch60with the clutch lever72until the accumulation is completed.

Then according to the transmission50in the present embodiment, as the accumulation can be completed before the disconnection operation of the clutch60, it is possible to more reliably realize the disconnection of the clutch60after the completion of the accumulation necessary for the shift operation. Accordingly, it is possible to more reliably perform quick shift operation after the disconnection of the clutch60.

In the transmission50in the present embodiment, the delay mechanism functions as a lost mechanism not to contribute a part of the rotational angle of the shift spindle55to the disconnection operation of the clutch60with the clutch lever72. Then according to the transmission50in the present embodiment, it is possible with the lost mechanism to easily complete the accumulation before the disconnection operation of the clutch60.

In the transmission50in the present embodiment, the clutch lever72and the accumulation collar71as a delay member have the mutually interlocked second doweled tooth71band second doweled hole72b. The delay mechanism is formed with the interval in the circumferential direction between the second doweled tooth71band the second doweled hole72b. Then according to the transmission50in the present embodiment, the delay mechanism has a compact and simple structure.

In the transmission50in the present embodiment, the delay mechanism is formed with the backlash in the moving direction in the clutch lifter plate77as a clutch lifter member which performs disconnection of the clutch60by moving with respect to the clutch60. Then according to the transmission50in the present embodiment, the delay mechanism has a simple structure.

In the transmission50in the present embodiment, the shift spindle55and the accumulation collar71integrally rotate. Accordingly, when the shift spindle55rotates, it is possible to quickly rotate the master arm83via the accumulation collar71, the accumulation spring57and the like.

In the transmission50in the present embodiment, the accumulation spring57as an accumulation mechanism is provided so as to directly cover the peripheral surface of the shift spindle55. Accordingly, the accumulation mechanism has a compact structure.

Next, the first through the fifth modifications of the motorcycle according to the present invention will be described with reference to the drawings. The delay mechanism is not limited to a mechanism the functions as a lost mechanism not to contribute a part of the rotational angle of the shift spindle55to the disconnection operation of the clutch60with the clutch lever72, as in the case of the above-described embodiment. Note that in the description of the modifications, the same constituent elements as those in the above-described embodiment have the same reference numerals, and the explanations thereof will be omitted or simplified.

FIGS. 28(a) to28(c) are right side views showing structures and operations of principle parts of the delay mechanism according to a first modification. In the first modification, as shown inFIGS. 28(a) to28(c), the clutch lever72is linked to the clutch lifter cam74via the guide hole74cprovided in the clutch lifter cam74. Further, the delay mechanism is provided as an backlash hole74dof the guide hole74c.

More particularly, the roller73of the clutch lever72is provided and engaged with the guide hole74c. The distorted long-hole type guide hole74chas the backlash hole74dat its central part. The backlash hole74dextends along the rotational direction (the moving direction of the roller73) R1of the clutch lever72. Accordingly, even when the clutch lever72rotates in a status where the roller73is positioned in the backlash hole74d, the roller73merely moves in the extending direction of the backlash hole74d, and the clutch lifter cam74does not or almost does not rotate.

On the other hand, in the guide hole74c, a part adjacent to the backlash hole74dextends in a direction different from the rotational direction (the moving direction of the roller73) R1of the clutch lever72. Accordingly, in a status where the roller73is positioned in the adjacent part, when the clutch lever72rotates, then interlocked with the rotation, the roller73presses the adjacent part, and the clutch lifter cam74immediately rotates.

Next, the operation of the clutch lifter cam74in the modification1will be described. As shown inFIG. 28(a), the roller73of the clutch lever72is positioned in the backlash hole74d. As shown inFIGS. 28(a) and28(b), when the clutch lever72rotates in the rotational direction R1, the roller73moves in the extending direction of the backlash hole74d. Before the roller73arrives at the end of the backlash hole74d, the clutch lifter cam74does not or almost does not rotate. That is, the delay function works.

When the clutch lever72further rotates from the status where the roller73has arrived at the end of the backlash hole74dshown inFIG. 28(b), the roller73starts to press the guide hole74c. Accordingly, as shown inFIG. 28(c), the clutch lifter cam74rotates in the rotational direction R2, and by extension, the clutch lifter plate77(not shown inFIG. 28)also rotates in the rotational direction R2. With this arrangement, the disconnection (clutch lift) of the clutch60is performed.

According to the first modification, the delay mechanism is provided as the backlash hole74dof the guide hole74c. Accordingly, it is possible to increase the size of the guide hole74c(especially it is possible to prolong the guide length). Accordingly, it is possible to easily set and manage the accuracy of the delay function of the delay mechanism.

FIGS. 29(a) and29(b) are diagrams showing the principal parts of the delay mechanism according to a second modification.FIG. 29(a) is a right side view.FIG. 29(b) is a view taken along line A-A cross-sectional view shown inFIG. 29(a). In the second modification, as shown inFIG. 29(a), the clutch lever72is linked to the clutch lifter cam74. Note that different from the first modification, the distorted long-hole shaped guide hole74cof the clutch lifter cam74in the modification2does not have the backlash hole74d.

The clutch lifter cam74has groove lines74va plurality of (three) valley-shaped slope plates. As shown inFIGS. 29(a) and29(b), the groove lines74vare linked to the clutch lifter plate77via the three release balls79as ball-shaped members. A flat part74wextending in the rotational direction R2of the clutch lifter cam74is formed in the valley parts of the groove lines74v.

Further, the clutch lifter plate77has a plurality of (three) valley groove lines77vin surface of the clutch lifter cam74opposite to the groove lines74v. As shown inFIG. 29(b), a flat part77wextending in the rotational direction R2of the clutch lifter cam74is formed in the valley parts of the groove lines77v.

More specifically, the groove lines74vof the clutch lifter cam74and the groove lines77vof the clutch lifter plate77have a similar valley shape. The delay mechanism is provided as the flat parts74wformed in the groove lines74vof the clutch lifter cam74and the flat parts77wformed in the groove lines77vof the clutch lifter plate77.

Note that in the second modification, the flat part77wof the clutch lifter plate77may not be provided.

Next, the operation of the clutch lifter cam74in the second modification will be described. As shown inFIG. 29(b), the release balls79are provided between the flat parts74wformed in the groove lines74vof the clutch lifter cam74and the flat parts77wformed in the groove lines77vof the clutch lifter plate77. When the clutch lever72rotates in the rotational direction R1, the release balls79moves in the extending direction of the flat part74wand the flat part77w. Before the release balls79arrive at the end of the flat part74wor the flat part77w, the clutch lifter cam74does not or almost does not rotate. That is, the delay function works.

When the clutch lever72further rotates from the status where the release balls79have arrived at the end of the flat part74wand the flat part77w, the release balls79start to press the groove lines77vof the clutch lifter plate77. Accordingly, the clutch lifter plate77rotates in the rotational direction R2. With this arrangement, the disconnection (clutch lift) of the clutch60is performed.

According to the second modification, the delay mechanism is provided as the flat parts74wformed in the valley groove lines74vand the flat parts77wformed in the valley groove lines77v. Accordingly, it is possible to realize the delay mechanism with a simple structure.

FIGS. 30(a) to30(c) are right side views showing the structures and operations of the principal parts of the delay mechanism according to a third modification.FIG. 31is a diagram of the inside of the right side unit case cover49, viewed from the left side in the third modification.

In the third modification, as shown inFIGS. 30(a) to30(c), the clutch lever72is linked to the clutch lifter cam74. The clutch lifter cam74is linked to the clutch lifter plate77via the three release balls79as ball-shaped members. As shown inFIGS. 7,8,30(a) and31(a), the clutch lifter plate77has the anchor77ato rotate-stopped with respect to the transmission. The delay mechanism is provided as an elliptic locking hole49bto lock the anchor77a.

As shown inFIGS. 30(a) to30(c), the anchor77ais provided in an upper part of the clutch lifter plate77. The anchor77ahas a pair of thrust members77b,77brespectively at both ends of the clutch lever72in the rotational direction R1.

As shown inFIG. 31, the elliptic locking hole49bis provided in left inner surface of the right-side unit case cover49. The locking hole49bhas an elliptic shape which is long in the rotational direction R1of the clutch lever72. Note that a virtual line49cshown inFIG. 31is a virtual line indicating the shape when the locking hole has a complete round shape.

Next, the operation of the clutch lifter cam74in the third modification will be described. As shown inFIGS. 30(a) and30(b), when the clutch lever72rotates in the rotational direction R1, the clutch lifter cam74is to rotate in the rotational direction R2, and at the same, the clutch lifter plate77is also to rotate in the rotational direction R2via the release balls79. However, as the locking hole49bhas an elliptic shape which is long in the rotational direction R1of the clutch lever72, the anchor77aof the clutch lifter plate77moves in the moving direction R3until the thrust member77babuts on the locking hole49b. Thereafter, when the clutch lever72rotates in the rotational direction R1, the clutch lifter plate77rotates in the rotational direction R2with the anchor77aas a rotation center. More specifically, the delay function works. Then the disconnection (clutch lift) of the clutch60is performed.

According to the third modification, the clutch lifter plate77has the anchor77arotate-stopped with respect to the transmission, and the delay mechanism is provided as the elliptic locking hole46bto lock the anchor77a. Accordingly, it is possible to realize the delay mechanism with a simple structure.

FIGS. 32(a) to32(c) are right side views showing the structures and operations of the principal parts of the delay mechanism according to a fourth modification. In the fourth modification, as shown inFIGS. 32(a) to32(c), the clutch lever72is linked to the clutch lifter cam74with a cam surface74eprovided in the clutch lifter cam74. The delay mechanism is provided as an idle cam74fof the cam surface74e.

The clutch lifter cam74has the cam surface74eat its lower end. The cam surface74ehas the idle cam74fat its central part. The idle cam74fextends along the rotational direction R1of the clutch lever72. On the other hand, a top72fof the clutch lever72abuts on and presses the cam surface74e. In a status where the top72fof the clutch lever72is positioned in the idle cam74f, even when the clutch lever72rotates, the top72fmerely moves in the extending direction of the idle cam74f, and the clutch lifter cam74does not or almost does not rotate.

On the other hand, in the cam surface74e, a part adjacent to the idle cam74fextends in a direction different from the rotational direction R1of the clutch lever72. Accordingly, in a status where the top72fof the clutch lever72is positioned in the adjacent part, when the clutch lever72rotates, the top72fof the clutch lever72, interlocked with the rotation, presses the adjacent part, and the clutch lifter cam74immediately rotates.

Next, the operation of the clutch lifter cam74in the modification4will be described. As shown inFIG. 32(a), the top72fof the clutch lever72is positioned in the idle cam74f. As shown inFIGS. 32(a) and32(b), when the clutch lever72rotates in the rotational direction R1, the top72fmoves in the extending direction of the idle cam74f. Before the top72fof the clutch lever72arrives at the end of the idle cam74f, the clutch lifter cam74does not or almost does not rotate. That is, the delay function works.

When the clutch lever72further rotates from a status shown inFIG. 32(b) where the top72fof the clutch lever72has arrived at the end of the idle cam74f, the top72fstarts to press the cam surface74e. Accordingly, as shown inFIG. 32(c), the clutch lifter cam74rotates in the rotational direction R2, and by extension, the clutch lifter plate77also rotates in the rotational direction R2. With this rotation, the disconnection (clutch lift) of the clutch60is performed.

According to the fourth modification4, the clutch lifter cam74is provided with the cam surface74e, and the delay mechanism is provided as the idle cam74fof the cam surface74e. Accordingly, it is possible to realize the delay mechanism with a simple structure.

FIGS. 33(a) to33(c) are right side views showing the structures and operations of the principal parts of the delay mechanism according to a fifth modification. In the fifth modification, as shown inFIGS. 33(a) to33(c), the clutch lever72is provided as a link mechanism to which a plurality of arm members721,722(first arm member721and second arm member722) are connected. In the link mechanism, the one member, first arm member721has a stopper721ato limit the rotational angle of the other member, second arm member722. The delay mechanism is provided as a rotatable range for the respective first arm member721and the second arm member722in the link mechanism.

The clutch lifter cam74has the cam surface74eat its lower end. The cam surface74ehas a circular-arc concave member74gat its central part.

The clutch lever72is formed with the first arm member721on the clutch60side and the second arm member722on the shift spindle55side linked to each other. The first arm member721has the stoppers721a,721aat a connection part between the first arm member721and the second arm member722. The stoppers721a,721aare provided as a pair in the rotational direction R1of the clutch lever72. The stopper721afunctions as a thrust member to abut on a side surface of the second arm member722, to limit the rotational angle of the second arm member722.

The top72fof the clutch lever72(first arm member721) abuts on the cam surface74e(including the circular-arc concave member74g) and presses it. In a status where the top72fof the clutch lever72is positioned in the circular-arc concave member74g, even when the clutch lever72rotates, the top72fmerely rotates inside the circular-arc concave member74g, and the clutch lifter cam74does not or almost does not rotate.

On the other hand, in the cam surface74e, a part adjacent to the circular-arc concave member74gextends approximately linearly. Accordingly, in a status where the top72fof the clutch lever72is positioned in the adjacent part, when the clutch lever72rotates, the top72fof the clutch lever72, interlocked with the rotation, presses the adjacent part, and the clutch lifter cam74rotates in the rotational direction R2.

Next, the operation of the clutch lifter cam74in the fifth modification will be described. As shown inFIG. 33(a), the top72fof the clutch lever72is positioned in the circular-arc concave member74g. As shown inFIGS. 33(a) and33(b), when the second arm member722of the clutch lever72rotates, the second arm member722rotates until it thrusts on the stopper721aof the first arm member721. At this time, the clutch lifter cam74does not or almost does not rotate. That is, the delay function works.

When the second arm member722further rotates from the status where the second arm member722thrusts on the stopper721aof the first arm member721shown inFIG. 33(b), the top72fstarts to press the cam surface74e. Accordingly, as shown inFIG. 33(c), the clutch lifter cam74rotates in the rotational direction R2, and by extension, the clutch lifter plate77rotates in the rotational direction R2. With this arrangement, the disconnection (clutch lift) of the clutch60is performed.

According to the fifth modification, the clutch lever72is provided as a link mechanism to which the plurality of arm members721,722are linked, and the delay mechanism is provided as a rotatable range for the respective arm members721,722in the link mechanism. When the delay mechanism is provided on the clutch60side, generally, it is necessary to provide a structure to realize a large sized delay in the clutch lifter cam74or the like. On the other hand, it is possible to set a compact delay mechanism by forming the clutch lever72with a link mechanism and providing the delay mechanism as a rotatable range for the respective arm members721,722in the link mechanism.

The plurality of gears of the gear array52G is formed with a dog clutch having a dog tooth (convex member) and a dog hole (concave member), in which a rotational drive force is transmitted between coaxially adjacent gears with the engagement of the dog tooth and the dog hole in the axial direction. In this case, upon shift operation, there is a probability that a “dog abutment” status where the dog tooth is not inserted in the dog hole occurs and the shift drum90is not positioned in an intermittent predetermined shift position.

Further, an angle sensor (position sensor) to detect the rotational angle of the shift drum90is provided. Based on the detected rotational angle, it is determined what shift position the shift drum90is positioned, or whether or not it is not positioned in any shift position due to dog abutment or the like, i.e., it is determined whether or not the shift operation in the shift drum90has been normally performed.

FIG. 34is a diagram corresponding toFIG. 27, explaining shift spindle control upon occurrence of dog abutment. In this example, shifting from the 1st gear to the 2nd gear will be described. When the shifting has been normally performed, as indicated in [4] inFIG. 27, the rotational angle of the shift drum90is quickly changed. On the other hand, when dog abutment occurs in the middle of shifting, as shown inFIG. 34, the rotational angle of the shift drum90is an angle between a rotational angle corresponding to the 1st gear and a rotational angle corresponding to the 2nd gear, and the angle is continued. Accordingly, in accordance with this status, it is determined that dog abutment has occurred.

Then, when the dog abutment (not positioned in any shift position) is determined, in the range indicated in [12] inFIG. 34, the following control (countermeasure) is performed.

When dog abutment is determined (see [11] inFIG. 13), the shift motor100is forward-rotated from the reverse status. When the amount of clutch lift is about a clutch spring effective range, the operation of the shift spindle55is stopped. Thereafter, the clutch60is gradually connected until the shift drum90rotates (until the position of the shift drum90moves to the 2nd gear position). The angle of the shift spindle55upon rotation of the shift drum90is stored (see [13] inFIG. 34), then based on the stored angle, timing of forward rotation start of the shift motor100is corrected.

Further, an oil temperature sensor for measurement of oil temperature is provided for the actuator to disconnect/connect the clutch60. It is preferable that when the oil temperature measured with the oil temperature sensor is high, the operation amount of the actuator is reduced, on the other hand, when the oil temperature measured with the oil temperature sensor is low, the operation amount of the actuator is increased.

As described above, the preferred embodiments of the present invention have been described. The present invention is not limited to the above-described embodiments, but can be implemented in various forms.

For example, the vehicle to which the transmission of the present invention is applied is not limited to a motorcycle but may be other saddle-ride type vehicle than the motorcycle.