JP4606927B2 - Vehicle speed change mechanism - Google Patents

Description

  The present invention relates to a transmission mechanism for a vehicle, and more particularly to a transmission mechanism suitable for a motorcycle.

  FIG. 22 shows an example of a conventional speed change mechanism of a motorcycle (see Patent Document 1), which is configured to sequentially disengage the clutch and change speed by operating only the change lever (change pedal). A change shaft 204, a change arm 205, a change pole 207, and the like. A petal-shaped drive plate 202 is fixed to the end face of the change drum 201 in the axial direction, and a plurality of drive pins 203 are fixed to the drive plate 202 at equal intervals in the circumferential direction. On the other hand, a change lever (not shown) is fixed to the change shaft 204 and the change arm 205 is fixed, and the change pole 207 is rotatably connected to a distal end portion of the change arm 205 via a connecting pin 206. Has been. The change pole 207 extends toward the drive plate 202 of the change drum 201 and has a pair of engagement claws 210a and 210b. The engagement claws 210a and 210b are moved by the movement of the change pole 207 in the pole length direction. The change drum 201 is engaged with the drive pin 203 and rotated by a predetermined rotation angle.

  A clutch release clutch arm (release arm) 213 is also fixed to the change shaft 204, and the clutch arm 213 engages with a pin 216 of a release cam plate 215 of a multi-plate friction clutch, for example. The release cam plate 215 is rotated by a certain angle by the clutch arm 213, thereby disconnecting the multi-plate friction clutch.

  Each of the engaging claws 210a and 210b has a predetermined clearance Su in the pole length direction with respect to the opposing drive pins 203 and 203, respectively, in order to secure a play stroke and a clutch release stroke at the initial stage of the change operation. It is opposed across Sd.

  The operation of the speed change mechanism shown in FIG. 22 will be briefly described. When the change shaft 204 is rotated in the direction of the arrow U, for example, by a depressing operation of the change lever, the change arm 205 and the clutch arm 213 are moved in the same direction as the change shaft 204 (arrow U First, the clutch plate 215 is rotated by the clutch arm 213 to disconnect the clutch. During the clutch disengagement operation, the change pole 207 moves in the pole length direction by the rotation of the change arm 205, but moves in the gap Su between one engagement claw 210a and the drive pin 203 facing the engagement claw 210a. Therefore, the change drum 201 does not rotate and the speed change operation does not start.

When the change shaft 204 is further rotated after the clutch is disengaged, one engagement claw 210a is engaged with the opposing drive pin 203, and the change drum 201 is rotated by a predetermined angle via the drive pin 203. Thereby, as is well known, the shift fork of the speed change mechanism is moved and shifted.
Japanese Patent Laid-Open No. 9-236175

  When the transmission mechanism shown in FIG. 22 is made compact, the change arm 205 and the change pole 207 are shortened. However, when the change arm 205 is shortened, the operation stroke for a certain amount of operation stroke is shortened. That is, the movement amount (operation stroke) of the change pole 207 in the pole length direction with respect to the rotation angle of the change shaft 204 or the depression amount (operation stroke) of the change lever decreases. In this case, since the stroke for rotating the change drum 201 by a predetermined angle cannot be reduced, the gaps Su and Sd between the engaging claws 210a and 210b and the driving pins 203 and 203 facing these must be narrowed. No. Then, the play stroke and the clutch release stroke before the start of the rotation of the change drum 201 are shortened, and the necessary play stroke and the clutch release stroke cannot be secured, so that there is no allowance for the change operation.

  If the shifting mechanism is made compact and the play stroke and the clutch release stroke before the start of the change drum rotation are to be ensured to be equal to those before the compacting, the engaging claws 210a and 210b and the drive pins 203 and 203 are used. It is necessary to make the operation stroke of the change lever longer than before the compactness without changing the gaps Su and Sd. However, while maintaining the comfort of the change operation from the viewpoint of layout and use of the change lever It is difficult to lengthen the operation stroke of the change lever. That is, it is difficult to make the speed change mechanism compact while maintaining the play stroke and the clutch release stroke during the change operation as usual and maintaining the comfort of the change lever operation.

  Although the distance from the shaft core of the change drum 201 to the drive pin 203 is shortened and the distance between the drive pins 203 is narrowed, it is possible to cope with the shortening of the dimension of the change arm 205. As the distance from the axis of the change drum 201 to the drive pin 203 is shortened, the change operation becomes heavy and the smooth operation of the change drum 201 cannot be maintained.

  An object of the present invention is to reduce the size of a vehicle speed change mechanism while maintaining a comfortable change operability and maintaining a play stroke, a clutch release stroke, etc. in the change operation as usual. is there.

In order to solve the above-mentioned problem, the vehicle speed change mechanism according to the first aspect of the present invention is provided with an arm main body 71 fixed to the change shaft 18 and supported by the arm main body 71 so as to be freely movable via a floating support portion. An idler member 72, and the idler member 72 is disposed in a state of being separated from the change shaft 18, and has an engaging portion 96 that can be engaged with the drive pin 65 of the change drum 20 , The biasing member is maintained at a standby position within a free range with respect to the arm body 71, and the free support portion is provided on a free pin provided on at least one of the free member 72 and the arm main body 71 and on the other side. In addition to the arm main body 71, the change pin 18 is mounted on the vehicle. The operating arm 44 for operating the clutch is fixed, and the floating member 72 and the arm main body 71 are moved relatively by a fixed amount by the turning operation of the change shaft 18, and the operation is performed during the moving. The clutch operation is performed by the arm 44, and then the change drum 20 is rotated by the engaging portion 96 of the floating member 72 .

According to the above configuration, the speed change mechanism can be made compact while maintaining the comfort of the change operation without increasing the operation stroke of the change lever.
Further, since the engagement between the floating pin and the floating hole is utilized, the structure of the floating support portion is simple and can be made compact in the axial direction. In addition, a long operating stroke can be ensured.

A vehicle speed change mechanism according to a second aspect of the present invention includes an arm main body 71 fixed to the change shaft 18, and a floating member 72 supported by the arm main body 71 so as to be freely movable via a floating support portion, The floating member 72 is disposed in a state of being separated from the change shaft 18, and has an engaging portion 96 that can be engaged with the drive pin 65 of the change drum 20. 71, the idler member 72 has a rotation fulcrum located in the region of the arm body 71 when viewed in the axial direction of the change shaft 18, and The floating member can be turned about the turning fulcrum in the same direction as the turning direction of the arm main body 71 turning about the axis of the change shaft 18, and the floating member can be moved by turning the change shaft 18. 72 and the above After the body 71 has floating by relatively constant amount, and so as to rotate said change drum 20 by the engaging portion 96 of the floating member 72.

According to the above configuration, the speed change mechanism can be made compact while maintaining the comfort of the change operation without increasing the operation stroke of the change lever. Moreover, even when viewed in the axial direction, the arm body and the floating member can be arranged in a compact manner.

A vehicle speed change mechanism according to a third aspect of the present invention is the vehicle speed change mechanism according to the first or second aspect, wherein the idle support portions are a first idle support portion 81 and a second idle support portion 82. The first floating support portion 81 is provided with a first floating pin 85 on one of the floating member 72 and the arm main body 71, and the first floating pin 85 has play on the other. The first floating hole 84 to be inserted is provided, and the second floating support portion 82 is provided with the first floating hole 84 out of the floating member 72 and the arm body 71. A second floating pin 86 is provided, a second floating hole 87 is provided on the side where the first floating pin 85 is provided, and a floating support portion acting on the floating member 72 during the change operation is the first The floating support portion 81 is changed to the second floating support portion .

  According to the above configuration, for example, the lever ratio between the arm main body and the floating member can be set so as to be suitable for a range where a light operating force is required and a range where a long operating stroke is desired even with a heavy operating force. .

A vehicle speed change mechanism according to a fourth aspect of the present invention is the vehicle speed change mechanism according to the second aspect, wherein the vehicle includes a clutch, the clutch operating arm 44 is provided on the change shaft 18, and the change gear By rotating the shaft 18, the clutch is operated before the change operation.

According to the above configuration, the clutch release operation and the change operation can be continuously performed by the same change lever operation while the transmission mechanism is compact, and the speed change operation is simplified.

According to a fifth aspect of the present invention, there is provided the vehicle transmission mechanism according to the third aspect, wherein the distance from the change axis to the first idler support portion 81 is from the change axis to the second axis. It is set longer than the distance to the floating support portion 82 .

  According to the above configuration, the operating force can be reduced in the initial and first half of the change operation where a light operating force is desired, and the operating stroke can be lengthened in the second half of the change operation requiring a long operating stroke, thus improving the operational feeling. To do.

A vehicle speed change mechanism according to a sixth aspect of the present invention is the vehicle speed change mechanism according to any one of the first to fifth aspects, wherein the change shaft 18 is shifted up and down. Further, a jumping prevention portion that abuts against the floating member 72 and restricts the maximum stroke of the floating member 72 is provided .

According to the above configuration, it is possible to prevent an overshift during any operation of shifting and downshifting with a simple structure.

A vehicle transmission mechanism according to a seventh aspect of the present invention is the vehicle transmission mechanism according to any one of the first to sixth aspects, wherein the return spring 75 returns the arm body 71 to the original position at the time of non-change operation. And an engagement prevention plate 78 for preventing the return spring 75 from engaging with the floating hole formed in the floating member 72 or the arm main body 71 .

According to the above configuration, smooth operability of the change mechanism can be ensured.

The vehicle transmission mechanism according to an eighth aspect of the present invention is the vehicle transmission mechanism according to any one of the first to seventh aspects, wherein the biasing member is provided between the arm body 71 and the floating member 72. Coil springs 73 and 74 are interposed, and the folded portions at the ends of the coil springs 73 and 74 that engage with the engagement holes formed in the arm main body 71 or the floating member 72 are connected to the coil springs 73 and 74. It extended almost parallel to the center line of 74 .
According to the above configuration, it is possible to prevent the coil spring from being disengaged against vibration and impact.

A vehicle transmission mechanism according to a ninth aspect of the present invention is the vehicle transmission mechanism according to the second aspect, wherein a fulcrum pin 94 serving as a pivotal fulcrum of the floating member 72 is formed on the floating member 72. It passes through the insertion hole 92 and is inserted into a long hole 91 formed in the arm body 71 .
According to the above configuration, the change arm assembly can be made compact when viewed in the change shaft length direction.

  In short, according to the present invention, since the idler support portion is provided in the change arm assembly for power transmission between the change shaft and the change drum, the operating stroke including the idle stroke is ensured in the conventional size. However, the transmission mechanism can be made compact. In addition, by providing a plurality of floating support portions with different distances from the change axis, for example, in an up stroke and down shift operation, or in a range that requires a light operating force and a heavy operating force In the range where it is desired to ensure a long time, the operation stroke can be set so as to suit each, and the operational feeling can be improved. Furthermore, by providing a common jump-preventing section for upshifting and downshifting, it is possible to prevent over-rotation in any operation during upshifting and downshifting operations with a small number of parts. it can.

  1 to 21 are examples in which the present invention is applied to a motorcycle, and an embodiment of the present invention will be described based on the drawings. FIG. 1 is a right side view (right side as viewed from the rider) in which the right crankcase cover 2 (see FIG. 2) of the crankcase 1 is removed and only the change arm assembly 3 and the clutch release mechanism 4 of the transmission mechanism are shown by solid lines. And is indicated by an arrow with the vehicle forward direction as the front. In FIG. 1, a crankcase 1 has a cylinder 6 and a cylinder head 8 sequentially coupled to a front end, and a transmission case 7 integrally formed at a rear portion. A crankshaft 9 extending in the direction of the crankshaft 9 is rotatably supported, and a centrifugal automatic clutch 11 is attached to the right end of the crankshaft 9.

  In the transmission case 7, a transmission input shaft 15, a transmission output shaft 16, a shift fork support shaft 17, a change shaft 18, a change drum 20, a kick starter shaft 21, and the like are arranged in parallel with the crankshaft 9. . The transmission output shaft 16 is disposed at the rear portion in the transmission case 7 and is disposed at substantially the same height as the crankshaft 9. A multi-plate friction clutch 12 is mounted on the right end portion of the transmission input shaft 15.

[Layout of each axis, etc.]
The transmission input shaft 15, the change shaft 18, the change drum 20, and the change arm assembly 3 are arranged between the axial center O 1 of the crankshaft 9 and the axial center O 2 of the transmission output shaft 16 (in the interval X). In addition, when the surface (line) M connecting the shaft core O1 of the crankshaft 9 and the shaft core O2 of the transmission output shaft 16 is used as a reference surface for the shaft height, the transmission input shaft 15 is located above the reference surface M. The change drum 20, the change shaft 18 and the change arm assembly 3 are arranged below the reference plane M. More specifically, the change shaft 18 is disposed rearward and lower than the change drum 20, and the change arm assembly 3 extends forward and upward from the change shaft 18 toward the change drum 20.

[Clutch structure]
FIG. 2 is an enlarged development view taken along the line II-II of FIG. 1, and shows an axis O4 of the change shaft 18, an axis O5 of the change drum 20, an axis O3 of the multi-plate friction clutch 12 and the transmission input shaft 15. It is cut and unfolded on a plane passing through the crankshaft 9 and the axis O1 of the centrifugal automatic clutch 11. The change lever 59 is shown in plan view. In FIG. 2, the centrifugal automatic clutch 11 includes an inner plate 23 fixed to the crankshaft 9, a clutch outer 25 fitted to the crankshaft 9 via a one-way clutch portion 24 and a bearing member, and the inner plate. 23, and a clutch shoe 27 that is supported by a pin 26 so as to be pivotable and moves outward in the radial direction of the crankshaft 9 against a spring or the like by centrifugal force. When the clutch shoe 27 is expanded radially outward by the centrifugal force and the rotational speed of the crankshaft 9 becomes a predetermined value or more, the clutch shoe 27 is pressed against the clutch outer 25 and the centrifugal automatic clutch 11 is connected. It is like that. The one-way clutch portion 24 does not transmit the rotation of the crankshaft 9 in the positive rotation direction from the crankshaft 9 to the clutch outer 25, and only rotates the crankshaft 9 in the positive rotation direction from the clutch outer 25 to the crankshaft 9. Thus, the engine brake can be applied on a downhill, for example.

  The multi-plate friction clutch 12 supports a plurality of friction plates 31 so as to be movable in the axial direction and is alternately arranged in the axial direction with respect to the friction plate 31 and the inner hub 32 fixed to the transmission input shaft 15. A clutch outer 35 that supports the plurality of clutch plates 33 so as to be movable in the axial direction and is rotatably supported on the crankshaft 9, and a pressure member 36 that presses the friction plate 31 and the clutch plate 33 in the axial direction. A clutch spring 38 that urges the pressure member 36 in the clutch connection direction (arrow C2 direction), a spring receiver / push member 39 that is fixed to the pressure member 36 and holds the clutch spring 38 in a compressed state, The clutch release mechanism 4 moves the push member 39 in the clutch disengagement direction (arrow C1 direction) against the elastic force of the clutch spring 38. With which, nipped and the friction plate 31 and the clutch plate 33 between the flange portion 32a of the pressure member 36 and the inner hub 32, and a clutch connected state. The input gear 41 fixed to the clutch outer 35 meshes with a gear 42 formed on the boss portion 25 a of the clutch outer 25 of the centrifugal automatic clutch 11, and the centrifugal type is engaged with the gear 42 and the input gear 41. Power is transmitted from the automatic clutch 11 to the multi-plate friction clutch 12. The cam-type clutch release mechanism 4 is actuated by a clutch arm (release lever) 44 fixed to the right end of the change shaft 18 as will be described in detail later.

  3 is an enlarged cross-sectional view of the clutch release mechanism 4 of the multi-plate friction clutch 12. The clutch release mechanism 4 includes a release bearing 45 fitted to the inner peripheral surface of the push member 39, and the release bearing 45. A push shaft 46 fitted to the inner peripheral surface of the inner ring, a support shaft 47 fixedly attached to the crankcase cover 2 and fitted and supported so that the push shaft 46 can move in the axial direction and turn. A sleeve 48 screwed to the support shaft 47, a movable cam plate 50 fixed to the push shaft 46, a fixed cam plate 51 fixed to the sleeve 48, and the both cam plates 50, 51 are sandwiched. A plurality of cam steel balls 52 are provided.

  The movable cam plate 50 is rotatable integrally with the push shaft 46 and is movable in the axial length direction, and integrally has an operation arm portion 50a protruding outward in the radial direction. A tip recess 44a of the clutch arm 44 is engaged with a pin 49 fixed to the tip of 50a. The stationary cam plate 51 is formed with an anti-rotation arm portion 51a protruding outward in the radial direction, and the anti-rotation pin 53 fixed to the arm portion 51a is inserted into the pin hole 54 of the crankcase cover 2. Thus, the rotation of the fixed cam plate 51 is prevented.

  4 is an enlarged development view of the IV-IV cross section of FIG. 3. Both cam plates 50 and 51 are formed with V-shaped cam surfaces 50b and 51b opposed to each other in the axial length direction. 52 is sandwiched between the cam surfaces 50b and 51b, and the steel ball 52 is movable on the movable side regardless of the rotation direction B1 or B2 of the movable cam plate 50 relative to the fixed cam plate 51. By rolling in the same direction as the cam plate 50 and moving from the bottom of both cam surfaces 50b and 51b to the flat surface side, the movable cam plate 50 is pushed in the clutch disengagement direction (arrow C1 direction). Yes.

[Transmission mechanism]
In FIG. 2, the speed change mechanism includes the change drum 20, the change arm assembly 3 for rotating the change drum 20 by a predetermined angle, the change shaft 18, the change lever 59, and a change gear (not shown). A shift fork that engages with the outer peripheral cam groove 60 of the drum 20 is provided.

  The change drum 20 is rotatably supported by the crankcase 1 via a bearing 61. When the change drum 20 is rotated, the shift fork is moved in the axial length direction via the outer peripheral cam groove 60, and the gear type. The speed change mechanism is changed. A drive plate 63 located in the clutch chamber 62 is fixed to the right end surface of the change drum 20.

  FIG. 10 is a right side view of the change drum 20 during the non-change operation. A plurality of, for example, five drive pins 65 are provided on the petal-shaped drive plate 63 fixed to the change drum 20 in the circumferential direction. At the outer peripheral edge of the drive plate 63, the same number of positioning recesses 63a as the drive pins 65 are formed at equal intervals in the circumferential direction. A positioning lever 66 is disposed below the drive plate 63. The positioning lever 66 has a lower end lever shaft 67 rotatably supported by the crankcase 1 and the like, and has a roller portion 66a at the tip. The roller portion 66 a is in contact with the outer peripheral edge of the drive plate 63 by the biasing spring 68. In other words, the tip roller portion 66a engages with the corresponding recess 63a at the rotational position of the change drum 20 at each gear position, and the change drum 20 is positioned at a predetermined position.

  FIG. 5 is an exploded perspective view of the change shaft 18 and the change arm assembly 3. A change lever (change pedal) 59 is fixed to the left end portion of the change shaft 18 and the clutch release lever is used for the clutch release as described above. The clutch arm 44 is fixed, and the change arm assembly 3 is provided on the left side of the clutch arm 44 at a constant interval in the axial direction. The change lever 59 is provided with a rod-shaped front end step portion 59a and a plate-shaped rear end step portion 59b. By stepping down the front end step portion 59a of the change lever 59, the change shaft 18 is shifted up. The change shaft 18 is rotated in the downshift direction (arrow D direction) by rotating in the direction (arrow U direction) and pushing up the front end stepping portion 59a or stepping on the rear end stepping portion 59b. . θu is the maximum operation stroke when the change lever 59 is shifted up, and is approximately 14 °, for example. θd is the maximum operation stroke when the change lever 59 is shifted down, and is, for example, approximately 18.5 °.

  The change arm assembly 3 includes a metal plate arm body 71 fixed to the change shaft 18, a metal plate floating member 72 movably connected to the arm body 71, and the floating member 72 as an arm. A pair of coil springs 73 and 74 that are maintained in a standby position before play with respect to the main body 71, a return coil spring 75 that returns the arm main body 71 to the original position at the time of non-change operation, the return coil spring 75, and the floating member The arm main body 71 and the floating member 72 are connected to and supported by the arm main body 71 so that the floating member 72 is movably connected to the arm main body 71. An idle support part 81 and a second idle support part 82 are provided.

  The first floating support portion 81 is fixed to the first floating hole 84 formed in the vicinity of the outer peripheral end portion in the radial direction of the arm body 71 and the floating member 72 and is circumferentially connected to the first floating hole 84. The first floating pin 85 is inserted so as to have a gap (play). The second floating support portion 82 is formed on the second floating pin 86 fixed to the radially inward side of the first floating hole 84 of the arm body 71 and the floating member 72, and the second floating support portion 82 is formed on the floating member 72. The second floating hole 86 is inserted so that the first floating pin 86 has a gap (play) in the circumferential direction. A flange 85a having a large diameter is integrally formed at the distal end portion of the first floating pin 85, and a partial arc-shaped flange portion 86a for retaining is also formed at the distal end of the second floating pin 86. Is formed.

  Projections 89 each having a spring engagement hole 88 are formed at both ends in the circumferential direction of the outer peripheral end of the arm body 71 in the radial direction. A joint hole 90 is formed, and the pair of coil springs 73 and 74 are stretched over the spring engagement holes 88 of the arm body 71 and the spring engagement holes 90 of the floating member 72, respectively.

  An arc-shaped long hole 91 for restricting the maximum amount of rotation of the arm main body 71 is formed on the inner side in the radial direction from the second idler pin 86 of the arm main body 71. A pin insertion hole 92 extending radially inward from the second floating hole 87 is formed at a position corresponding to the long hole 91, and an arc-shaped pin insertion hole 93 is also formed in the engagement preventing plate 78. Is formed. The return coil spring 75 is wound around the change shaft 18 and extends linearly outward in the radial direction with both end portions 75a and 75b being parallel to each other. The crankcase 1 is fixed with a fulcrum / rotation amount regulating pin 94 that functions as a rotation fulcrum of the floating member 72 and restricts the maximum amount of rotation of the arm main body 71. The arm main body 71 extends rightward in the longitudinal direction, passes between the linear end portions 75a and 75b of the return coil spring 75, the pin insertion hole 93 of the engagement preventing plate 78, and the pin insertion hole 92 of the floating member 72. In the long hole 91. The circumferential width of the pin insertion hole 92 of the floating member 72 is approximately the size corresponding to the outer diameter of the fulcrum / rotation amount regulating pin 94.

  A bending portion 95 that is bent inward in the radial direction is integrally formed at the radially outer peripheral end portion of the idler member 72, and the bending portion 95 has a pair of engagement claws for driving a change drum (or Engaging recesses 96 and 97 are formed to face each other at a predetermined interval in the circumferential direction. The engagement claw 96 on the arrow D direction side (upper side) is for shifting up, and the engagement claw on the arrow U direction side (lower side) is for shifting down.

  A single stopper 56 is disposed at a position near the outside in the radial direction of the idler member 72 to prevent the change drum 20 from jumping (over-rotating) during the change operation as shown in FIG. Has been. The stopper 56 is disposed at a substantially central position in the circumferential direction of the change arm assembly 3 during a non-change operation.

  FIG. 6 is an enlarged front view of the coil spring 73 for maintaining the standby position. An extension 73b extending substantially parallel to the center line of the coil spring 73 is formed on one of the hook portions 73a at both ends to prevent the coil spring 73 from coming off. Thus, the coil spring 73 is prevented from coming off due to impact or the like after assembly. FIG. 7 is an enlarged cross-sectional view of the engagement hole 88 of the arm main body 71 (VII-VII cross-sectional enlarged view of FIG. 5), and both opening edges of the engagement hole 88 are enlarged toward the opening side. A tapered surface 88a is formed, and the extension 73b of the coil spring 73 shown in FIG. 6 can be easily engaged. Note that the coil spring 74 and the engagement hole 88 on the lower side in FIG. 5 have the same structure as the coil spring 73 and the engagement hole 88 in FIGS.

  FIG. 8 shows the state of the change arm assembly 3 and the clutch release mechanism 4 during a non-change operation, that is, when the rotation angle of the change shaft 18 is 0 °. However, the flange 85a of the first floating pin 85 is omitted. In the state of FIG. 8, the arm body 71 is maintained at the original position before the rotation by the return coil spring 75 via the second floating pin 86, and the floating member 72 is moved by the two coil springs 73 and 74. The arm main body 71 is maintained at a standby position before play. The clutch arm 44 has a tip recess 44a engaged with a pin 49 of the protrusion 50a of the movable cam plate 50 when the clutch is engaged.

  The state of the first floating support portion 81 during the non-change operation shown in FIG. 8 is such that the circumferential edges 84a and 84b of the first floating hole 84 are circumferential with respect to the first floating pin 85, respectively. They are opposed to each other with a certain gap (play) Su1, Sd1 in the direction. The gap Su1 between the edge 84a on the arrow D direction side (upper side) and the first floating pin 85 ensures play for the floating member 72 and the arm body 71 to relatively move during the upshifting operation. In the following, the end edge 84a on the arrow D direction side of the first floating hole 84 is referred to as "first shift-up end edge". On the other hand, the clearance Sd1 between the edge 84b on the arrow U direction side (lower side) and the first floating pin 85 ensures play for the floating member 72 and the arm body 71 to relatively move during the downshift operation. Hereinafter, the edge 84b on the arrow U direction side of the first floating hole 84 is referred to as “first shift-down edge”.

  FIG. 9 is a right side view of the floating member 72 during the non-change operation. The state of the second floating support portion 82 is such that the respective circumferential edges of the second floating hole 87 are the first edges 87a and 87b. The two floating pins 86 are opposed to each other with gaps Su2 and Sd2 in the circumferential direction. The gap Su2 between the end edge 87a on the arrow U direction side (lower side) and the second floating pin 86 is the first upshift of the first floating hole 84 in FIG. After the contact edge 84a and the first floating pin 85 are in contact with each other, a play for allowing the floating member 72 of FIG. 9 and the arm main body 71 (FIG. 8) to move relative to each other is secured. The edge 87a on the arrow U direction side of the second floating hole 87 is referred to as a “second shift-up edge”. Note that the gap Sd2 between the edge 87b on the arrow D side and the second floating pin 86 is the same as the edge 87b and the second edge during the entire operation stroke from the start of the operation to the end of the shift operation during the downshift operation. The size of the floating pin 86 is set so as not to contact. Hereinafter, the end edge 87b of the second floating hole 87 on the arrow D direction side is referred to as “non-working end edge”.

  FIG. 10 shows the relationship between the drive pin 65 of the change drum 20 and the engaging claws 96 and 97 of the floating member 72 during the non-change operation. In FIG. On the other hand, the engaging claws 96 and 97 of the floating member 72 are opposed to each other with gaps (plays) Su0 and Sd0 in the circumferential direction. The gap Su0 and the gap Sd0 are almost equal in size. A gap Su0 between the engagement claw 96 on the arrow D direction side (upper side) and the drive pin 65 facing the engagement claw 96 ensures play at the beginning of the upshift operation. A clearance Sd0 between the engagement claw 97 on the arrow U direction side (lower side) and the drive pin 65 facing the engagement claw 97 ensures play at the beginning of the downshift operation.

The operation and operation will be described.
[Shift-up operation and operation]
In the shift-up operation, the change shaft 18 is turned in the shift-up direction (arrow U direction) by stepping on the front end step portion 59a of the change lever 59 in FIG. Rotate in the direction. By this shift-up operation, as a first stage operation, the clutch arm 44 disconnects the multi-plate friction clutch 12 (see FIG. 2), while the change arm assembly 3 is armed in the first half of the first stage. The main body 71 and the floating member 72 are rotated (moved) by a rotation angle corresponding to the clearance Su0 between the drive pin 65 of the change drum 20 and the shift-up engagement claw 96 in FIG. 10, and in the latter half of the first stage. The arm main body 71 rotates (moves) with respect to the floating member 72 by a rotation angle corresponding to the clearance Su1 between the first shift-up end edge 84a and the first floating pin 85 in FIG. Therefore, the change drum 20 does not rotate in the entire first stage. As the second stage operation, the first shift-up end edge 84a pushes the first floating pin 85, thereby rotating the floating member 72 in the direction of the arrow U. Then, the change drum 20 is rotated in the direction of the arrow Au via the drive pin 65. Then, as the third stage operation, the second idler pin 86 pushes the second shift-up end edge 87a, whereby the idler member 72 is further rotated in the arrow U direction, and the change drum 20 is finally rotated. It rotates in the direction of the arrow Au to the position, and the speed change operation is completed. Hereinafter, each operation stage will be described in detail.

(1) First Stage Operation From the state at the time of non-change operation of FIGS. 8 to 10 (the rotation angle of the change shaft 18 is 0 °) to the state of FIGS. 11 to 13 (the rotation angle of the change shaft 18 is 6.8). Up to °).

  First, the operation of the first half of the first stage will be described. When the change shaft 18 starts to rotate in the arrow U direction from the state of FIG. 8, the movable cam plate 50 moves to the arrow via the tip recess 44 a and the pin 49 of the clutch arm 44 due to the rotation of the clutch arm 44 in the same direction. The movable cam plate 50 is rotated in the B1 direction, and the movable cam plate 50 is moved in the clutch disengagement direction (arrow C1 direction) in FIG. 3 by the cam action of both the cam plates 50, 51 and the steel ball 52. The pressure member 36 shown in FIG. 2 moves in the clutch disengagement direction (arrow C1 direction) via the release bearing 45 and the push member 39, thereby disconnecting the multi-plate friction clutch 12.

  The arm main body 71 of FIG. 8 also rotates about the axis O4 of the change shaft 18 in the direction of the arrow U, and the second free pin 86 causes the straight end portion 75a on the arrow U direction side of the return coil spring 75 to move to the arrow U. Push in the direction. The other linear end 75 b of the return coil spring 75 is locked by a support / rotation amount regulating pin 94.

  First, the rotational force is transmitted from the arm main body 71 via the coil springs 73 and 74 to the idler member 72, and the contact portion P1 between the support / rotation amount regulating pin 94 and the pin insertion hole 92 shown in FIG. As a rotation fulcrum, the idler member 72 rotates in the arrow U direction.

  By the rotation of the floating member 72 in the direction of the arrow U, the shift-up engagement claw 96 shown in FIG. 10 approaches the opposite drive pin 65 and moves a distance corresponding to the shift-up clearance Su0. 65, the movement of the floating member 72 is temporarily stopped by the drive pin 65. Thereby, the operation | movement of the first half of a 1st step is complete | finished. During the operation of the first half, the coil springs 73 and 74 in FIG. 8 hardly expand and contract, and the change drum 20 is maintained in the stopped state by the locking action of the positioning arm 66. Further, the shift-up end edge 84a of the first floating hole 84 of the arm body 71 approaches the first floating pin 85 but does not come into contact therewith.

  Next, the operation in the latter half of the first stage will be described. When the change shaft 18 is further rotated in the direction of the arrow U after the shift-up engagement claw 96 of FIG. 94, and the shift-up engagement claw 96 is engaged with the drive pin 65, so that the substantially stopped state is maintained. On the other hand, the arm main body 71 moves in the arrow U direction relative to the floating member 72 while extending the coil spring 74 on the arrow U direction side and simultaneously compressing the coil spring 73 on the opposite side. That is, it moves relatively. During this time, when the first shift-up edge 84a approaches the first floating pin 85 and moves through the clearance Su1, the first shift-up edge 84a contacts the first floating pin 85 (FIG. 11). Status). As a result, the operation in the latter half of the first stage is completed. The multi-plate friction clutch 12 has been disengaged at least by the end of the operation of the first stage.

  During the operation of the first stage, the second floating pin 86 of FIG. 9 approaches the second shift-up edge 87a of the floating member 72, but at the end of the operation of the first stage, the second abutment pin 86 abuts as shown in FIG. It does not lead to. When the end 75a of the return coil spring 75 is opened as shown in FIG. 11, the tip of the end 75a moves to a position corresponding to the second loose hole 87 or the pin insertion hole 92 of the loose member 72. Even so, as shown in FIG. 5, since the engagement preventing plate 93 is disposed between the floating member 72 and the return coil spring 75, the end portion 75 a of the return coil spring 75 is connected to the second floating hole 87. Or, it does not fall into the pin insertion hole 92.

(2) Second Stage Operation After the first stage operation is completed, the operation is performed up to the state shown in FIGS. 14 and 15 (the rotation angle of the change shaft 18 is 10 °).

  As shown in FIG. 11, after the first shift-up end edge 84a of the first floating hole 84 comes into contact with the first floating pin 85, when the change shaft 18 is further rotated in the arrow U direction, The first floating pin 85 is pushed in the direction of the arrow U by the first shift-up end edge 84a, whereby the floating member 72 is brought into contact with the abutment portion P1 between the support / rotation amount regulating pin 94 and the pin insertion hole 92. Is turned in the direction of arrow U, and the shift-up engagement claw 96 pushes the drive pin 65 in the direction of arrow U as shown in FIG. 13, thereby turning the change drum 20 in the direction of arrow Au. . That is, a substantial shift operation is started. Further, the second floating pin 86 of FIG. 12 further approaches the second shift-up end edge 87a of the second floating hole 87 of the floating member 72, and the second stage of the second stage shown in FIGS. At the end of the operation, the second floating pin 86 comes into contact with the second shift-up end edge 87a of the second floating hole 87.

  In the second stage operation, the rotational force of the arm main body 71 in FIG. 11 is transmitted to the floating member 72 via the first shift-up end edge 84a and the first floating pin 85. The floating support portion 81 is an abutting portion P1 between the shaft O4 of the change shaft 18 serving as a rotation fulcrum of the arm body 71 and the support / rotation amount regulating pin 94 serving as a rotation fulcrum of the floating member 72 and the pin insertion hole 92. Therefore, the change drum 20 can be rotated by a light operation.

(3) Third Stage Operation From the state shown in FIGS. 14 and 15 (the rotation angle of the change shaft 18 is 10 °) to the state at the end of the shift operation shown in FIG. 16 (the rotation angle of the change shaft 18 is 14.5 °). ) Operation.

  As shown in FIG. 14, after the second floating pin 86 comes into contact with the second shift-up end edge 87a of the second floating hole 87, when the arm body 71 further rotates in the arrow U direction, this time. The second floating pin 86 of the arm body 71 pushes the second shift-up end edge 87a of the second floating hole 87 in the direction of the arrow U, and the floating member 72 is supported by the support / rotation amount regulating pin 94 and the pin. It rotates in the direction of the arrow U with the contact portion P1 with the insertion hole 92 as a rotation fulcrum. As a result, the shift-up engagement claw 96 pushes the drive pin 65 further in the direction of the arrow Au, and the change drum 20 is rotated to the final rotation position shown in FIG. In this third stage of operation, the second floating pin 86 slides slightly outward in the radial direction along the second shift-up edge 87a of the second floating hole 87, As a result, the first shifting-up end edge 84a of the first floating pin 85 and the first floating hole 84 are separated from each other.

  In the third stage as described above, the second floating support portion 82 acting on the floating member 72 from the arm main body 71 is compared with the first floating support portion 81 in the axial center of the change shaft 18 ( The arm fulcrum 71 is provided at a position close to any of the contact portion (rotation fulcrum of the floating member 72) P1 between the support / rotation amount regulating pin 94 and the pin insertion hole 92. Compared with the second stage in which the first floating support portion 81 acts, it is possible to increase the amount of movement (actuation stroke) of the engaging claw with respect to a certain operation stroke of the change lever 59 (FIG. 5). That is, a large operation stroke can be earned by a small operation stroke by the change lever 59 of FIG.

(4) Over-rotation prevention When the change lever 59 has a strong momentum, the change drum 20 may attempt to over-rotate from the final rotation position shown in FIG. 16 due to its inertia. In addition, the drive pin 65 of the next position in the direction of the arrow Ad is in contact with the radially inner end of the bent portion 95 of the floating member 72, and the radially outer end edge of the bent portion 95 is in contact with the stopper 56. Thus, the over rotation of the change drum 20 and the over rotation of the change arm assembly 3 are prevented.

(5) Return operation After the completion of the shift-up operation, when the pedaling force is released from the front end stepping portion 59a of the change lever 59 of FIG. 5, the arm is moved from the state of FIG. 16 (or the state of FIG. 17) by the restoring force of the return coil spring 75. While the main body 71 returns to the original position in FIG. 8 in the direction of arrow D, the floating member 72 returns to the standby position in FIG. 8 in the direction of arrow D by the restoring force of both coils 73 and 74.

[Shift-down operation and operation]
In the downshift operation, the front end step portion 59a of the change lever 59 in FIG. 5 is pushed upward or the rear end step portion 59b is stepped on, whereby the change shaft 18 is rotated in the direction of the arrow D, thereby the clutch arm 44 And the arm main body 71 is rotated in the arrow D direction. By this downshifting operation, as a first stage operation, the clutch arm 44 disconnects the multi-plate friction clutch 12 (FIG. 2). On the other hand, the change arm assembly 3 is the arm body in the first half of the first stage. 71 and the floating member 72 are rotated (moved) by a rotation angle corresponding to the clearance Sd0 of the shift-down engagement claw 97 with the drive pin 65 of the change drum 20 in FIG. 10, and in the second half of the first stage. 8, the arm body 71 moves relative to the floating member 72 by a rotation angle corresponding to the gap Sd1 between the first shift-down end edge 84b of the arm body 71 and the first floating pin 85 of the floating member 72. Rotates (is idle). Therefore, the change drum 20 does not rotate in the entire first stage. As a second stage of operation, the first shift-down end edge 84b of the arm body 71 pushes the first idle pin 85 of the idle member 72, thereby rotating the idle member 72 in the direction of arrow D and changing drum. 20 is rotated to the final rotation position, and the speed change operation is completed. Hereinafter, the operation of each stage will be described in detail.

(1) Operation in the first stage From the state in the non-change operation of FIGS. 8 to 10 (the rotation angle of the change shaft 18 is 0 °) to the state of FIGS. 18 and 19 (the rotation angle of the change shaft 18). Up to 5 °).

  Compared with the operation at the time of upshifting, the rotation directions of the change shaft 18, the movable cam plate 50, the arm main body 71, the idler member 72, and the change drum 20 are reversed, and the shift down engaging claws The basic operation is the same except that 97 and the first shift-down edge 84b of the first floating hole 84 are used, and redundant explanations are increased. explain.

  When the change shaft 18 starts to rotate in the direction of arrow D from the state of FIG. 8, the movable cam plate 50 moves to the arrow via the tip recess 44 a of the clutch arm 44 and the pin 49 due to the rotation of the clutch arm 44 in the same direction. The movable cam plate 50 is rotated in the direction B2, and the movable cam plate 50 is moved in the clutch disengagement direction (arrow C1 direction) in FIG. 3 by the cam action of both the cam plates 50 and 51 and the steel ball 52. The pressure member 36 shown in FIG. 2 moves in the clutch disengagement direction (arrow C1 direction) via the release bearing 45 and the push member 39, thereby disconnecting the multi-plate friction clutch 12.

  The arm main body 71 of FIG. 8 also rotates in the direction of arrow D around the axis O 4 of the change shaft 18, and the straight end 75 b on the arrow D direction side of the return coil spring 75 is moved by the second floating pin 86 to the arrow D. Push in the direction. The linear end portion 75 a on the arrow U direction side of the return coil spring 75 is locked by a support / rotation amount regulating pin 94.

  First, the rotational force is transmitted from the arm main body 71 to the idler member 72 via both coil springs 73 and 74, and the contact portion P2 between the support / rotation amount regulating pin 94 and the pin insertion hole 92 shown in FIG. As a rotation fulcrum, the floating member 72 rotates in the direction of arrow D. The contact portion P2 is located on the opposite side in the circumferential direction from the contact portion P1 during the shift-up.

  By the rotation of the floating member 72 in the direction of arrow D, the shift-down engagement claw 97 shown in FIG. 10 approaches the opposing drive pin 65 and moves a distance corresponding to the shift-down gap Sd0. 65, the movement of the floating member 72 is temporarily stopped by the drive pin 65. Thereby, the operation | movement of the first half of a 1st step is complete | finished. During the operation of the first half, the coil springs 73 and 74 in FIG. 8 hardly expand and contract, and the change drum 20 is maintained in the stopped state by the locking action of the positioning arm 66. Further, the shift-down end edge 84b of the first floating hole 84 of the arm body 71 approaches the first floating pin 85 but does not come into contact therewith.

  Next, the operation in the latter half of the first stage will be described. When the change shaft 18 is further rotated in the direction of the arrow D after the shift down engagement pawl 97 of FIG. 8 is engaged with the opposing drive pin 65, the pin insertion hole 92 is a support / rotation amount regulating pin. 94, and the shift-down engagement claw 97 is engaged with the drive pin 65, so that the substantially stopped state is maintained. On the other hand, the arm main body 71 moves in the arrow D direction relative to the floating member 72 while extending the coil spring 73 on the arrow D direction side and simultaneously compressing the coil spring 74 on the opposite side. That is, it moves relatively. During this time, when the first shift-down edge 84b approaches the first floating pin 85 and moves through the gap Sd1, the first shift-down edge 84b contacts the first floating pin 85 (FIG. 18). Status). As a result, the operation in the latter half of the first stage is completed. The multi-plate friction clutch 12 has been disengaged at least by the end of the operation of the first stage.

  During the first stage of operation, the second floating pin 86 of the arm main body 71 of FIG. 18 approaches the non-working edge 87b of the floating member 72, but does not come into contact.

(2) Second Stage Operation From the state shown in FIGS. 18 and 19 (the rotation angle of the change shaft 18 to −9.5 °) to the state at the end of the speed change operation shown in FIG. 20 (the rotation angle 18 of the change shaft 18). Up to °).

  As shown in FIG. 18, after the shift-down end edge 84b of the first idler hole 84 abuts on the first idler pin 85, when the change shaft 18 further rotates in the direction of arrow D, the first idler The shift-down edge 84b of the hole 84 pushes the first floating pin 85 in the direction of the arrow D, so that the floating member 72 is brought into contact with the contact portion P2 between the support / rotation amount regulating pin 94 and the pin insertion hole 92. Is moved in the direction of the arrow D with the rotation fulcrum as a rotation fulcrum, and the change drum 20 is rotated in the direction of the arrow Ad to the final rotation position shown in FIG.

  During this second stage of operation, the second floating pin 86 of the arm body 71 approaches the non-working edge of the second floating hole 87 of the floating member 72 but does not come into contact therewith.

(4) Over-rotation prevention When the momentum of the depressing operation of the change lever 59 in FIG. 5 is strong, the change drum 20 may attempt to over-rotate from the final rotation position in FIG. 20 due to its inertia. 21, the next drive pin 65 in the direction of the arrow Au contacts the radially inner end of the bent portion 95 of the floating member 72, and the radially outer end edge of the bent portion 95 serves as the stopper 56. In this way, over rotation of the change drum 20 and over rotation of the change arm assembly 3 are prevented.
[Effect of the embodiment of the invention]

(1) With respect to the arm main body 71 fixed to the change shaft 18, an idle member 72 having engagement claws 96 and 97 that engage with the drive pin 65 of the change drum 20 is provided via the idle support portions 81 and 82. Since it is connected and supported so as to be freely movable, the operation stroke θu and θd of the change lever 59 is not increased, and the change arm assembly 3 is made compact, but the play before rotation of the change drum 20 is performed as an operating stroke. Therefore, the operating stroke including the stroke for the clutch release and the stroke for the clutch release can be increased, and the speed change mechanism can be made compact while maintaining the comfort of the change operation. In addition, the clutch release operation and the change operation can be continuously and smoothly performed by operating the same change lever 59 while making the speed change mechanism compact.

(2) The first floating support portion 81 and the second floating support portion 82 are provided, and support and rotation that is the axis O 4 of the change shaft 18 that is the pivot point of the arm body 71 and the pivot point of the floating member 72. The first floating support portion 81 is disposed at a position far from any position of the contact portion P1 between the movement amount regulating pin 94 and the pin insertion hole 92, and the second floating support portion 82 is disposed at a position close to the shift portion. During the up operation, the first floating support portion 81 at a distant position acts in the first half of the operation, and the second floating support portion 82 at a near position acts in the second half of the operation. In the first half of the operation, the operation can be performed with a light operating force, and in the second half of the operation in which a long operation stroke is desired, a large operation stroke can be obtained with a short operation stroke, and operation comfort can be obtained in the entire shift-up operation.

(3) Since the floating support portions 81 and 82 are constituted by the floating pins 85 and 86 provided in one of the arm body 71 or the floating member 72 and the floating holes 84 and 87 provided in the other, the floating support portion The structure of 81 and 82 is simplified, and the dimension in the axial direction is compact.

(4) Since there is a jumping prevention stopper 56 that abuts against the floating member 72 and regulates the maximum stroke of the floating member 72 at any time of shifting up and down, it has a simple structure. It is possible to prevent the change drum 20 from over-rotating during both shift and shift-down operations.

(5) Since the engagement preventing plate 93 is disposed between the floating member 72 and the return coil spring 75, the end portions 75a and 75b of the return coil spring 75 are used for the second floating during the upshifting or downshifting operation. It does not fall into the hole 87 or the pin insertion hole 92, and smooth operability can be ensured.

(6) As shown in FIG. 6, an extension 73b extending substantially parallel to the center line of the coil spring 73 is formed on one end of the hook portions 73a of the coil spring 73 (74) to prevent the coil spring 73 from coming off. After the assembly, it is possible to prevent the coil spring 73 from coming off due to an impact or the like, and as shown in FIG. 7, tapers that increase in diameter toward the opening side at both opening edges of the engagement hole 88 of the arm body 71. Since the surface 88a is formed, the linear extension 73b of the coil spring 73 as shown in FIG. 6 can be easily engaged.

[Other Embodiments of the Invention]
(1) In the above-described embodiment, the first and second floating support portions 81 and 82 are configured to act in two stages at the time of the shift up operation. The first and second floating support portions 81 and 82 can be configured to act sequentially, or only one floating support portion can be configured to operate during any operation.

(2) When a plurality of floating fulcrum portions are provided, the distance from the axis O4 of the change shaft 18 can be arbitrarily set in consideration of the layout of the change lever 59 of the motorcycle, the operation force, and the like.

(3) In the above-described embodiment, the idle pin 85 and the idle hole 84 common to the upshift idle support portion 81 are used as the upshift idle support portion. It is also possible to provide a structure for providing a dedicated suspension support section and a dedicated shift-down support section, in which case the operation force and operation stroke suitable for each of the up-shifting operation and the down-shifting operation are set. You can also.

(4) As a structure of the floating support portion, instead of the floating pin 85 and the floating hole 84, both the arm main body 71 and the floating member 72 are formed with protruding portions for floating at predetermined intervals in the circumferential direction, It can also be configured such that both protrusions engage after a certain play stroke has elapsed. Of course, various engagement structures such as a protrusion and a notch groove may be employed instead of the configuration of the protrusions.

(5) The speed change mechanism of the present invention can also be applied to a mechanism that does not release the clutch by a change operation.

FIG. 1 is a right side view showing only a crankcase, a speed change mechanism, and a clutch release mechanism, which is a vehicle engine equipped with a speed change mechanism to which the present invention is applied. It is the II-II cross-section expanded view of FIG. FIG. 3 is an enlarged cross-sectional view of the clutch release mechanism of FIG. 2. FIG. 4 is an expanded partial view of the IV-IV section of FIG. 3. It is a disassembled perspective view of a speed change mechanism and a clutch release mechanism. It is an enlarged front view of the coil spring for standby position maintenance. It is the VII-VII cross-sectional enlarged view of FIG. It is a right view which shows the state at the time of the non-change operation of a change arm assembly and a clutch release mechanism. It is a right view which shows the state at the time of non-change operation of a floating member. It is a right view which shows the state at the time of non-change operation of a change drum and a floating member. It is a right view which shows the state at the time of completion | finish of the 1st step of the upshift operation of a change arm assembly and a clutch release mechanism. It is a right view which shows the state at the time of completion | finish of the 1st step of the upshift operation of a floating member. It is a right view which shows the state at the time of completion | finish of the 1st step of a change drum and a floating member. It is a right view which shows the state at the time of completion | finish of the 2nd step of the upshift operation of a change arm assembly and a clutch release mechanism. It is a right view which shows the state at the time of completion | finish of the 2nd step of the upshift operation of a floating member. It is a right view which shows the state at the time of completion | finish of the 3rd step of the upshift operation of a change arm assembly and a clutch release mechanism. It is a right view which shows the state at the time of the over rotation prevention in the upshift operation of a change drum and a floating member. It is a right view which shows the state at the time of completion | finish of the 1st step of the downshift operation of a change arm assembly and a clutch release mechanism. It is a right view which shows the state at the time of completion | finish of the 1st step of the downshift operation of a change drum and a floating member. It is a right view which shows the state at the time of completion | finish of the 2nd step of the downshift operation of a change arm assembly and a clutch release mechanism. It is a right view which shows the state at the time of the over rotation prevention in the downshift operation of a change drum and a floating member. It is a right view of the conventional transmission mechanism.

Explanation of symbols

1 Crankcase 3 Change arm assembly 4 Clutch release mechanism 9 Crankshaft 12 Multi-plate friction clutch 18 Change shaft 20 Change drum 44 Clutch arm (operation arm for clutch release)
50 Movable cam plate 51 Fixed cam plate 52 Steel ball for cam 56 Stopper for jump prevention (jump prevention part)
59 Change lever (change pedal)
63 Drive plate 65 Drive pin 71 Arm body 72 Floating member 73, 74 Coil spring 73a for maintaining the standby position 73a Hook part 73b Linear extension part 75 Return coil spring 81 First idle support part 82 Second idle support part 84 First idle hole 84a First shift-up edge 84b First shift-down edge 85 First idle pin 86 Second idle pin 87 Second idle hole 87a Second downshift Edge 88 Spring engagement hole 88a Taper surface 94 Supporting point and rotation amount regulating pin 96 Shifting engagement claw (an example of an engagement portion)
97 Shifting down engaging claw (an example of engaging part)

Claims (9)

An arm main body (71) fixed to the change shaft (18), and a floating member (72) supported by the arm main body (71) via a floating support portion so as to be freely movable;
The floating member (72) is disposed in a state of being separated from the change shaft (18) and has an engaging portion (96) that can be engaged with the drive pin (65) of the change drum (20). The biasing member is maintained at a standby position within a free movement range with respect to the arm body (71) ,
The floating support portion is provided on at least one of the floating member (72) and the arm main body (71) and on the other, and the floating pin has play around the entire floating pin. A floating hole to be inserted, and
In addition to the arm body (71), an operating arm (44) for operating a clutch mounted on the vehicle is fixed to the change shaft (18).
By the turning operation of the change shaft (18), the floating member (72) and the arm body (71) move relatively by a fixed amount, and the clutch is operated by the operating arm (44) during the movement. And then the change drum (20) is rotated by the engaging portion (96) of the floating member (72) . An arm main body (71) fixed to the change shaft (18), and a floating member (72) supported by the arm main body (71) via a floating support portion so as to be freely movable;
The floating member (72) is disposed in a state of being separated from the change shaft (18) and has an engaging portion (96) that can be engaged with the drive pin (65) of the change drum (20). The biasing member is maintained at a standby position within a free movement range with respect to the arm body (71),
The floating member (72) has a rotation fulcrum located in the region of the arm main body (71) when viewed in the axial direction of the change shaft (18), and the change shaft (18) The arm main body (71) that rotates about the axis is rotatable about the rotation fulcrum in the same direction as the rotation direction of the arm body (71),
After the floating member (72) and the arm main body (71) are moved by a relatively fixed amount by the turning operation of the change shaft (18), the engaging portion (96) of the floating member (72) is moved. The change drum (20) is rotated by the vehicle speed change mechanism. The vehicle transmission mechanism according to claim 1 or 2,
The floating support portion includes a first floating support portion (81) and a second floating support portion (82),
As the first floating support portion (81), either the floating member (72) or the arm body (71) is provided with a first floating pin (85), and the other is the first floating pin (81). (85) is provided with a first floating hole (84) to be inserted with play,
Of the floating member (72) and the arm body (71), the second floating pin (86) is provided on the side having the first floating hole (84) as the second floating support portion (82). ), The second floating hole (87) is provided on the side where the first floating pin (85) is provided,
A vehicular transmission mechanism in which a floating support portion acting on the floating member (72) is changed from a first floating support portion (81) to a second floating support portion during a change operation. The vehicle transmission mechanism according to claim 2,
The vehicle is provided with a clutch, and a clutch operation arm (44) is provided on the change shaft (18), and the clutch is operated before the change operation by rotating the change shaft (18). , Vehicle transmission mechanism. The vehicle speed change mechanism according to claim 3,
A transmission mechanism for a vehicle, wherein a distance from a change shaft core to the first floating support portion (81) is set to be longer than a distance from a change shaft core to the second floating support portion (82). In the vehicle speed change mechanism according to any one of claims 1 to 5,
During both the operation of the shift-up and shift-down of the change shaft (18), provided with a preventing portion interlaced to regulate the maximum stroke of the free moving member abuts on the floating member (72) (72), vehicle Transmission mechanism. The vehicle transmission mechanism according to any one of claims 1 to 6,
A return spring (75) for returning the arm body (71) to the original position at the time of non-change operation is provided, and the return spring (75) is formed on the floating member (72) or the arm body (71). A vehicle transmission mechanism comprising an engagement preventing plate (78) for preventing engagement with a hole. The vehicle transmission mechanism according to any one of claims 1 to 7,
Coil springs (73, 74) are interposed between the arm body (71) and the floating member (72) as the biasing member,
The folded portion at the end of the coil spring (73, 74) that engages with the engagement hole formed in the arm body (71) or the floating member (72) is the center of the coil spring (73, 74). A transmission mechanism for a vehicle that extends substantially parallel to the wire. The vehicle transmission mechanism according to claim 2,
A fulcrum pin (94 ) serving as a rotation fulcrum of the floating member (72) passes through a pin insertion hole (92) formed in the floating member (72) and is formed in the arm body (71). A vehicle speed change mechanism inserted into the elongated hole (91).

Images