JP7385676B2 - transmission - Google Patents

Description

The present invention relates to a transmission.

a first gear arranged on the shaft and provided with first teeth on the end face in the axial direction; and a gear stage different from the gear stage constituted by the first gear, arranged on the shaft and provided with the third teeth on the end face in the axial direction. 2. Description of the Related Art Transmissions are known that include a third gear that is connected to a shaft, and a shift device that selectively couples the first gear and the third gear to a shaft. The transmission disclosed in Patent Document 1 changes the meshing between the first teeth and the first dog teeth when switching from a low gear to a high gear driven by the first gear, in which the first dog teeth mesh with the first teeth. The first ring moves in the direction of release. This makes it possible to achieve a so-called seamless shift, which suppresses interruptions in drive torque.

However, when the engagement between the first tooth and the first dog tooth is released, the first ring, the shift fork attached to the first ring, and the engagement that fixes the shift fork and engages with the cam groove of the shift drum Since the shift rod including the parts moves together, the impact is large when the shifted shift rod, shift fork, and first ring are brought to rest.

Therefore, the applicant placed a spring between the shift rod and the shift fork, formed an elongated hole in one of the shift rod and the shift fork, fixed a pin to the other of the shift rod and the shift fork, and fixed the pin in the elongated hole. filed a patent application for a transmission placed in a vehicle (Patent Document 2, unpublished at the time of filing). According to this transmission, when releasing the engagement between the first tooth and the first dog tooth, the shift rod is moved first, and then the shift fork and the first ring are moved by the elastic force of the spring, and the pin The movement of the shift fork and the first ring can be stopped by applying it to the elongated hole. Since the shift rod moves first, the kinetic energy can be reduced, so the impact when the shift fork and first ring are brought to rest can be suppressed.

Japanese Patent Application Publication No. 2012-127471 PCT/JP2019/48910

However, since the technology of Patent Document 2 has a structure in which the shift rod rotates and the pin moves in the circumferential direction in the elongated hole, the shift rod rotates too much and the engaging part integrated with the shift rod becomes attached to the cam of the shift drum. The cam groove may come off from the groove, or the engagement between the cam groove and the engaging portion may become shallow, causing the cam groove and the engaging portion to easily wear out. In addition, if the shift rod rotates too much in the opposite direction, the engaging part will be pressed against the bottom of the cam groove of the shift drum, which may impede rotation of the shift drum and cause the engaging part and cam groove to wear easily. or

The present invention was made to solve this problem, and provides a transmission that prevents wear of the cam grooves and engaging parts and prevents the engaging parts from falling off from the cam grooves, and ensures smooth rotation of the shift drum. is intended to provide.

In order to achieve this object, the transmission of the present invention includes a first gear that is arranged on a shaft and constitutes a predetermined gear stage and has first teeth on an end face in the axial direction, and a gear stage that the first gear constitutes. a third gear that constitutes a different gear stage and is disposed on the shaft and has third teeth on the end surface in the axial direction, and a shift device that selectively couples the first gear and the third gear to the shaft, The shift device includes an annular first hub that is coupled to the shaft, and a shift device that is arranged around the outer periphery of the first hub, is rotatably engageable with the first hub, and movable in the axial direction, and meshes with the first teeth. a first ring in which a first dog tooth is provided on an axial end surface and a third dog tooth that meshes with the third tooth on the other end surface; a first fork attached to the first ring; and a first cam. A shift drum in which a groove is formed, and a first rod in which a first engaging portion that engages with the first cam groove is disposed and moves the first fork in the axial direction along the first cam groove, The shift device includes a spring that is interposed between the first rod and the first fork and urges the first fork in the axial direction by an elastic force, and a spring that is formed in one of the first rod and the first fork in the axial direction. The first rod is provided with an extending elongated hole, a pin fixed to the other of the first rod and the first fork and disposed in the elongated hole, and a first engaging portion, the first rod being swingable in the circumferential direction of the first rod. the elongated hole has a first part extending in the axial direction from the first end of the elongated hole, and a first end connected to the first end of the first part; and a second part extending in the axial direction from the first end, the first ends of the first part and the second part are connected to each other in the circumferential direction, and the first part and the second part extend on opposite sides in the axial direction.

According to the transmission according to the first aspect, the first engaging portion is provided on the first arm that is swingably disposed on the first rod in a circumferential direction of the first rod. Even if the first rod rotates in a direction in which the first engaging portion separates from the first cam groove, the first arm relatively rotates and the first engaging portion remains in the first cam groove. Therefore, the first engaging part may fall off from the first cam groove, or the first cam groove and the first engaging part may become loose due to shallow engagement between the first cam groove and the first engaging part and a small contact area. can prevent wear. In addition, even if the first rod rotates in the direction in which the first engaging part approaches the bottom of the first cam groove, the first arm rotates relatively, so the first arm and the first engaging part are strong against the shift drum. It is possible to prevent the first engaging portion from being pressed, prevent wear of the first engaging portion, the shift drum, etc., and ensure smooth rotation of the shift drum.

The rail disposed along the shift drum contacts an outer portion of the first arm located on the outer side of the first rod in the radial direction. The outer portion is located between the rail and the shift drum. Therefore, it is possible to restrict the swinging of the first arm in the direction in which the first engaging portion separates from the bottom of the first cam groove.

According to the transmission according to claim 2 , the outer portion includes an inner surface of a hole formed in the first arm and parallel to the first rod. Since the rail passes through the hole, it is possible to restrict the swinging of the first arm in the direction in which the first engaging portion approaches the bottom of the first cam groove. Since the first engaging portion can be prevented from being strongly pressed against the bottom of the first cam groove, in addition to the effect of claim 1 , smooth rotation of the shift drum can be prevented from being hindered.

According to the transmission according to claim 3 , the second arm is provided integrally with the first arm, and the second arm extends toward the shift drum. A contact portion of the second arm contacts the outer peripheral surface of the shift drum. The contact portion contacts the outer circumferential surface of the shift drum at a position that includes a line of intersection between the outer circumferential surface of the shift drum and a virtual plane passing through the center axis of the first rod and the center axis of the shift drum. Therefore, the swinging of the first arm can be restricted by the second arm whose contact portion is in contact with the outer circumferential surface of the shift drum.

According to the transmission according to claim 4 , since the contact portion contacts both sides of the outer circumferential surface in the circumferential direction with respect to the intersection line, in addition to the effect of claim 3 , the contact portion contacts the first engagement from the groove bottom of the first cam groove. It is possible to limit the swinging of the first arm in the direction in which the parts move away from each other, and the swinging of the first arm in the direction in which the first engaging part approaches the groove bottom of the first cam groove.

It is a skeleton diagram of a transmission in one embodiment. FIG. 3 is a perspective view of a first hub with a first ring arranged thereon. FIG. 2 is a schematic diagram of a transmission in which a first rod and a second rod are in a neutral position. FIG. 3 is a cross-sectional view of the first rod on which the first fork is arranged. (a) is a plan view of the elongated hole seen from the direction of arrow Va in FIG. 4, (b) is a plan view of the elongated hole in a modified example, and (c) is a plan view of the elongated hole in another modified example. It is. (a) is a plan view of the first rod seen from the direction of arrow VIa in FIG. 3, (b) is a cross-sectional view of the first rod taken along line VIb-VIb in FIG. 6(a), and (c) is a 6(d) is a sectional view of the first rod taken along line VIc-VIc in FIG. 6(a), and FIG. 6(d) is a sectional view of the first rod taken along line VId-VId in FIG. 6(a). It is a perspective view of the shift device in a 1st embodiment. 8 is a cross-sectional view of the shift device taken along line VIII-VIII in FIG. 7. FIG. 8 is a front view of the shift device seen from the direction of arrow IX in FIG. 7. FIG. FIG. 3 is a schematic diagram of the transmission during drive driving in a low gear. FIG. 3 is a schematic diagram of the transmission during coasting in a low gear. FIG. 3 is a schematic diagram of an initial transmission that switches from a low gear to a high gear. FIG. 3 is a schematic diagram of a mid-range transmission that switches from a low gear to a high gear. FIG. 3 is a schematic diagram of the transmission at the final stage of switching from a low gear to a high gear. It is a perspective view of the shift device in a 2nd embodiment. 15 is a front view of the shift device seen from the direction of arrow XVI in FIG. 14. FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, a schematic configuration of a transmission 1 according to the present invention will be explained with reference to FIG. FIG. 1 is a skeleton diagram of a transmission 1 in one embodiment. The transmission 1 includes a drive shaft 2 to which power is input, and a driven shaft 3 arranged parallel to the drive shaft 2. An output gear 4 is arranged on the driven shaft 3. The drive shaft 2 and the driven shaft 3 support a first gear 10, a second gear 20, a third gear 30, a fourth gear 40, a fifth gear 50, and a sixth gear 60, which constitute a plurality of gear stages. In this embodiment, the transmission 1 is mounted on an automobile (not shown).

The first gear 10 includes a drive gear 11 fixed to the drive shaft 2 so as not to be relatively rotatable, and a driven gear 12 fixed to the driven shaft 3 so as to be relatively rotatable while constantly meshing with the drive gear 11. The second gear 20 includes a drive gear 21 fixed to the drive shaft 2 so as to be relatively rotatable, and a driven gear 22 fixed to the driven shaft 3 so as not to be relatively rotatable while constantly meshing with the drive gear 21. The third speed gear 30 includes a drive gear 31 fixed to the drive shaft 2 so as not to be relatively rotatable, and a driven gear 32 fixed to the driven shaft 3 so as to be relatively rotatable while constantly meshing with the drive gear 31.

The fourth gear 40 includes a drive gear 41 fixed to the drive shaft 2 so as to be relatively rotatable, and a driven gear 42 fixed to the driven shaft 3 so as not to be relatively rotatable while always meshing with the drive gear 41. The fifth gear 50 includes a drive gear 51 fixed to the drive shaft 2 so as to be relatively rotatable, and a driven gear 52 fixed to the driven shaft 3 so as not to be relatively rotatable while constantly meshing with the drive gear 51. The 6th gear 60 includes a drive gear 61 fixed to the drive shaft 2 so as to be relatively rotatable, and a driven gear 62 fixed to the driven shaft 3 so as not to be relatively rotatable while always meshing with the drive gear 61.

The transmission 1 further includes a shift device 70 that selectively couples gears to the drive shaft 2 and the driven shaft 3. The shift device 70 includes a first hub 71, a second hub 72, a third hub 73, a first ring 81, a second ring 82, a third ring 83, a first fork 101, a second fork 102, a third fork 103, It includes a first rod 104, a second rod 106, a third rod 108, and a shift drum 110.

The first hub 71 is an annular member disposed between the drive gear 41 and the drive gear 61 and coupled to the drive shaft 2 . The second hub 72 is an annular member disposed between the drive gear 21 and the drive gear 51 and coupled to the drive shaft 2 . The third hub 73 is an annular member disposed between the driven gear 12 and the driven gear 32 and coupled to the driven shaft 3.

A first tooth 43 that protrudes in the axial direction toward the first hub 71 is provided on the end surface of the drive gear 41 in the axial direction. A third tooth 63 that protrudes in the axial direction toward the first hub 71 is provided on the axial end surface of the drive gear 61 . A second tooth 53 that protrudes in the axial direction toward the second hub 72 is provided on an axial end surface of the drive gear 51 . A fourth tooth 23 that protrudes axially toward the second hub 72 is provided on the axial end surface of the drive gear 21 . A fifth tooth 13 that protrudes axially toward the third hub 73 is provided on an axial end surface of the driven gear 12 . A sixth tooth 33 is provided on an axial end surface of the driven gear 32 and protrudes in the axial direction toward the third hub 73 .

The first ring 81, the second ring 82, and the third ring 83 are rotatably engageable and axially movable with respect to the first hub 71, the second hub 72, and the third hub 73, respectively. They are arranged on the outer peripheries of the hub 71, the second hub 72, and the third hub 73, respectively. On the axial end surface of the first ring 81, first dog teeth 84 and 85 (see FIG. 3) protrude in the axial direction toward the drive gear 41, and first dog teeth 84 and 85 (see FIG. 3) protrude in the axial direction toward the drive gear 61. Three dog teeth 88, 89 (see FIG. 3) are provided.

On the axial end surface of the second ring 82, second dog teeth 93, 94 (see FIG. 3) protrude in the axial direction toward the drive gear 51, and second dog teeth 93, 94 (see FIG. 3) protrude in the axial direction toward the drive gear 21. Four dog teeth 97, 98 (see FIG. 3) are provided. On the axial end surface of the third ring 83, there are fifth dog teeth (not shown) that protrude in the axial direction toward the driven gear 12, and sixth dog teeth that protrude in the axial direction toward the driven gear 32. (not shown) is provided.

The first fork 101, the second fork 102, and the third fork 103 are attached to the first ring 81, the second ring 82, and the third ring 83, respectively. The first fork 101, the second fork 102, and the third fork 103 are fixed to the first rod 104, the second rod 106, and the third rod 108, respectively.

The shift drum 110 is a cylindrical member in which a first cam groove 111, a second cam groove 112, and a third cam groove 113 extending in the circumferential direction are formed on the outer periphery. The shift drum 110 is rotatably fixed to the case C, and rotated around a central axis by a motor (not shown). The first engaging portion 105 disposed on the first rod 104 engages with the first cam groove 111, and the second engaging portion 107 disposed on the second rod 106 engages with the second cam groove 112. A third engaging portion 109 disposed on the third rod 108 engages with the third cam groove 113.

The shift drum 110 rotates based on an operation signal from a shift lever (not shown), or based on an accelerator opening degree and a vehicle speed signal generated by operation of an accelerator pedal (not shown). When the shift drum 110 rotates, the first engaging portion 105, the second engaging portion 107, and the third engaging portion 109 are guided by the first cam groove 111, the second cam groove 112, and the third cam groove 113, respectively. The first fork 101, the second fork 102, and the third fork 103 move in the axial direction via the first rod 104, the second rod 106, and the third rod 108. As the first fork 101, second fork 102, and third fork 103 move in the axial direction, the first ring 81, the second ring 82, and the third ring 83 move in the axial direction.

The first hub 71 and the first ring 81 will be explained with reference to FIG. 2. FIG. 2 is a perspective view of the first hub 71 on which the first ring 81 is arranged. The configurations of the second hub 72 and the third hub 73 are the same as the configuration of the first hub 71, and the configurations of the second ring 82 and the third ring 83 are the same as the configuration of the first ring 81. Therefore, descriptions of the second hub 72, third hub 73, second ring 82, and third ring 83 will be omitted.

As shown in FIG. 2, a spline 74 coupled to the drive shaft 2 (see FIG. 1) is formed on the inner peripheral surface of the first hub 71. A groove 75 parallel to the central axis O of the first hub 71 is formed on the outer peripheral surface of the first hub 71 . The groove 75 is formed over the entire length of the first hub 71 in the axial direction.

The first ring 81 has first dog teeth 84, 85 that protrude from one end surface along the central axis O of the first ring 81, and third dog teeth 88, 89 that protrude in the axial direction from the other end surface. , is equipped with. The central axis O of the first hub 71 and the first ring 81 coincides with the central axis of the drive shaft 2. In this embodiment, the first dog tooth 84 is provided at the same position as the third dog tooth 88, and the first dog tooth 85 is provided at the same position as the third dog tooth 89. The first dog tooth 84 is longer than the first dog tooth 85 in the axial direction, and the third dog tooth 88 is longer than the third dog tooth 89 in the axial direction. The first dog teeth 84 are arranged alternately with the first dog teeth 85 in the circumferential direction, and the third dog teeth 88 are arranged alternately with the third dog teeth 89 in the circumferential direction.

The first dog teeth 84, 85 include a first surface 86 facing one circumferential direction, and a second surface 87 opposite the first surface 86 and facing the other circumferential direction. There is. The third dog teeth 88, 89 include a first surface 90 facing one side in the circumferential direction, and a second surface 91 opposite to the first surface 90 and facing the other side in the circumferential direction. There is. The first surfaces 86 and 90 are inclined surfaces that are inclined with respect to a virtual plane (not shown) parallel to the central axis O. The second surfaces 87 and 91 are surfaces parallel to the central axis O. The first surfaces 86 and 90 are inclined so that as they move away from the first ring 81 in the axial direction, they approach the second surfaces 87 and 91, respectively.

Teeth 92 parallel to the central axis O are provided on the inner surfaces of the first dog teeth 84 and the third dog teeth 88 . The teeth 92 are continuously continuous over the entire length of the first dog teeth 84 and the third dog teeth 88. The teeth 92 of the first ring 81 fit into the grooves 75 of the first hub 71 so that the first ring 81 can move axially relative to the first hub 71; Can't rotate around it.

FIG. 3 is a schematic diagram of the transmission 1 in which the first rod 104 and the second rod 106 are in the neutral position. In FIG. 3, illustration of the third cam groove 113 of the shift drum 110 and the drive gear 21 is omitted. The first engaging portion 105 and the second engaging portion 107 that respectively engage the first cam groove 111 and the second cam groove 112 of the shift drum 110 are located in the neutral region 114 of the shift drum 110, so that the first Rod 104 and second rod 106 are set to neutral positions.

A spring 129 (see FIG. 4) is disposed between the first rod 104 and the first fork 101, which biases the first fork 101 in the axial direction by elastic force. Similarly, the second fork 102 and the third fork 103 are urged in the axial direction by elastic force between the second rod 106 and the second fork 102 and between the third rod 108 and the third fork 103. A spring (not shown) is arranged. In the structure in which a spring is arranged between the second rod 106 and the second fork 102 or between the third rod 108 and the third fork 103, a spring 129 is arranged between the first rod 104 and the first fork 101. Since the structure is the same as that of , the explanation will be omitted.

FIG. 4 is a cross-sectional view of the first rod 104 on which the first fork 101 is disposed, when the first rod 104 is in the neutral position. In FIG. 4, illustration of a portion of the first rod 104 in the axial direction and a portion of the first fork 101 is omitted. The attachment part 120 of the first fork 101 is formed in a cylindrical shape and is attached to the outer periphery of the first rod 104. An elongated hole 121 is formed in the attachment portion 120 and extends in the axial direction and passes through the attachment portion 120 in the thickness direction. The cylindrical portion 122 surrounds the outer periphery of the first rod 104 with a space therebetween. One end of the cylindrical portion 122 is coupled to the attachment portion 120. A convex portion 123 (stopper) that protrudes radially inward is provided at the other end of the cylindrical portion 122.

Grooves are formed in the first rod 104 at intervals in the axial direction, and retaining rings 124 and 125 are respectively fixed to the grooves. The retaining ring 124 is located inside the cylindrical portion 122. Washers 126 and 127 each having an outer diameter larger than the outer diameter of the retaining rings 124 and 125 are arranged on the first rod 104 inside the retaining rings 124 and 125 in the axial direction. The washers 126 and 127 are arranged inside the cylindrical portion 122 with a space between them in the axial direction.

An annular elastic body 128 made of rubber, synthetic resin, or the like is interposed between the washer 127 and the convex portion 123 of the cylindrical portion 122 . A spring 129 is arranged between washer 126 and washer 127. In this embodiment, spring 129 is a compression coil spring. Since the distance between washer 126 and washer 127 is less than the free length of spring 129, spring 129 is preloaded. Due to the elastic force of the preloaded spring 129, the washer 126 is pressed against the retaining ring 124, and the washer 127 is pressed against the retaining ring 125.

A cylindrical spacer 130 (stopper) is arranged between the washer 126 and the mounting portion 120. An annular elastic body 131 made of rubber or synthetic resin is interposed between the spacer 130 and the attachment portion 120. The static spring constants of the elastic bodies 128 and 131 are smaller than the static spring constant of the spring 129.

The attachment portion 120, the elastic body 131, the spacer 130, and the washer 126 are lined up with no gaps between each other, and the washer 127, the elastic body 128, and the convex portion 123 are lined up with each other without any gaps. Due to the elastic force of the preloaded spring 129, it is difficult to form a gap between the spacer 130 and the washer 126, and it is difficult to form a gap between the elastic body 128 and the convex portion 123, so that the first rod 104 is in the neutral position. , the axial position of the first fork 101 on the first rod 104 is fixed without wobbling. Since the restoring of the spring 129 is restricted by the retaining rings 124 and 125, the elastic force of the spring 129 is not applied to the first fork 101 (attachment portion 120) when the first rod 104 is in the neutral position.

A hole 132 passing through the central axis O of the first rod 104 is formed in a portion of the first rod 104 where the attachment portion 120 is arranged. The pin 133 is fixed in the hole 132, and the end of the pin 133 is placed in the elongated hole 121. The first rod 104 can rotate relative to the mounting portion 120 of the first fork 101 by the circumferential gap between the pin 133 and the elongated hole 121 .

FIG. 5(a) is a plan view of the elongated hole 121 viewed from the direction of arrow Va in FIG. The elongated hole 121 includes a first part 134 and a second part 142. The first portion 134 includes a first end 135 in the axial direction, a second end 136 on the opposite side of the first end 135 in the axial direction, and a portion between the second end 136 and the first end 135. An intermediate portion 137 is provided. The second portion 142 includes a first end 143 in the axial direction, a second end 144 on the opposite side of the first end 143, and an intermediate portion 145 between the second end 144 and the first end 143. It is equipped with

The first ends 135 and 143 of the elongated hole 121 are portions that overlap each other in the circumferential direction. The second ends 136, 144 have arcuate edges formed on the outer circumferential surface of the attachment portion 120. The first end portions 135 and 143 of the first portion 134 and the second portion 142 are connected in the circumferential direction of the attachment portion 120, and the second end portions 136 and 144 are located on opposite sides in the axial direction. The circumferential center position of the second portion 142 is shifted from the circumferential center position of the first portion 134 in the first circumferential direction (arrow I direction). When the first rod 104 is in the neutral position, the pin 133 is located at the first ends 135, 143.

Since the circumferential width of the first part 134 is larger than the thickness of the pin 133, the first rod 104 pushes the spring 129 until the pin 133 hits the axial wall surface 139 of the second end 136 of the first part 134. It can be compressed and moved relative to the first fork 101 in the axial direction. When the compressed spring 129 is restored, the pin 133 rests against the axial wall 138 of the first end 135.

Further, since the width of the second portion 142 in the circumferential direction is larger than the thickness of the pin 133, the first rod 104 is held in place by the spring until the pin 133 hits the wall surface 147 in the axial direction of the second end portion 144 of the second portion 142. 129 and can move relative to the first fork 101 in the axial direction. When the compressed spring 129 is restored, the pin 133 rests against the axial wall surface 146 of the first end 143.

The wall surface 148 of the first end 143 of the second part 142 in the first direction (direction of arrow I) and the wall surface 148 of the first end 135 of the first part 134 in the second direction (direction of arrow II) on the opposite side of the first direction ) and the wall surface 140 becomes longer from the center line O of the first rod 104 toward the outside in the radial direction (toward the front side in the drawing). This makes it easier for the pin 133 to rotate relative to the elongated hole 121 at the first ends 135 and 143.

A wall surface 149 in the first direction (arrow I direction) of the intermediate portion 145 of the second portion 142 smoothly connects to a wall surface 148 in the first direction of the first end portion 143 of the second portion 142 , and A wall surface 141 of the portion 137 in the second direction (arrow II direction) smoothly connects to a wall surface 140 of the first end portion 135 of the first portion 134 in the second direction. Thereby, when the compressed spring 129 is restored, the pin 133 can be moved toward the first end 135 along the wall surface 141 of the first portion 134, and can be easily brought to rest against the wall surface 138. Similarly, when the compressed spring 129 is restored, the pin 133 can be moved toward the first end 143 along the wall 149 of the second portion 142, and can be easily brought to rest against the wall 146.

In this embodiment, a plane including the wall surfaces 140, 141 of the first part 134 and a plane including the wall surfaces 148, 149 of the second part 142 are parallel to the center line O of the first rod 104 (not in a twisted position). ). As a result, when the pin 133 is located at the second end portions 136, 144, the pin 133 cooperates with the shift check mechanism 170 (described later) to rotate the first rod 104 relative to the first fork 101. Friction between the second end portions 136 and 144 and the wall surfaces of the second end portions 136 and 144 can be suppressed.

FIG. 5(b) is a plan view of the elongated hole 150 in a modified example. The elongated hole 150 has a first portion 151 that includes a first end 135, a second end 136, and an intermediate portion 137 in the axial direction, and a first portion 143, a second end 144, and an intermediate portion 145 in the axial direction. A second part 154 is provided. The second end 136 of the first part 151 and the second end 144 of the second part 154 are on a plane that includes the centerline O of the first rod 104.

The wall surface 155 of the first end 143 of the second part 154 in the first direction (direction of arrow I) and the wall surface 155 of the first end 135 of the first part 151 in the second direction (direction of arrow II) on the opposite side to the first direction. ) and the wall surface 152 becomes longer from the center line O of the first rod 104 toward the outside in the radial direction (toward the front side in the drawing). This makes it easier for the pin 133 to rotate relative to the elongated hole 150 at the first ends 135 and 143.

A wall surface 156 in the first direction (direction of arrow I) of the intermediate portion 145 of the second portion 154 smoothly connects to a wall surface 155 in the first direction of the first end portion 143 of the second portion 154 . The wall surface 153 of the portion 137 in the second direction (arrow II direction) smoothly connects to the wall surface 152 of the first end portion 135 of the first portion 151 in the second direction. Thereby, when the compressed spring 129 is restored, the pin 133 can be moved toward the first end 135 along the wall surface 153 of the first portion 151, and can be easily brought to rest against the wall surface 138. Similarly, when the compressed spring 129 is restored, the pin 133 can be moved along the wall surface 156 of the second portion 154 toward the first end portion 143, making it easier to rest against the wall surface 146.

In this embodiment, a plane including the wall surfaces 152 and 153 of the first part 151 and a plane including the wall surfaces 155 and 156 of the second part 154 obliquely intersect with the center line O of the first rod 104. Thereby, the area of the wall surfaces 138, 146 in the axial direction of the first ends 135, 143 can be made larger than the area of the wall surfaces 138, 146 in the elongated hole 121 (see FIG. 5(a)). Further, when the pin 133 is located at the second end portions 136 and 144, it is easy to obtain a reaction force that rotates the first rod 104 with respect to the first fork 101 in cooperation with the shift check mechanism 170 (described later). Become.

FIG. 5(c) is a plan view of the elongated hole 157 in another modification. The elongated hole 157 includes a first portion 158 that includes a first end 135, a second end 136, and an intermediate portion 137 in the axial direction, and a first portion 143, a second end 144, and an intermediate portion 145 in the axial direction. A second part 161 is provided. The second end 136 of the first part 158 and the second end 144 of the second part 161 are on a plane that includes the centerline O of the first rod 104.

The wall surface 162 of the first end 143 of the second part 161 in the first direction (direction of arrow I) and the wall surface 162 of the first end 135 of the first part 158 in the second direction (direction of arrow II) on the opposite side to the first direction. ) and the wall surface 159 becomes longer from the center line O of the first rod 104 toward the outside in the radial direction (towards the front in the drawing). This makes it easier for the pin 133 to rotate relative to the elongated hole 157 at the first ends 135 and 143.

A wall surface 163 in the first direction (arrow I direction) of the intermediate portion 145 of the second portion 161 smoothly connects to a wall surface 162 in the first direction of the first end portion 143 of the second portion 161 , and The wall surface 160 of the portion 137 in the second direction (arrow II direction) smoothly connects to the wall surface 159 of the first end portion 135 of the first portion 158 in the second direction. Thereby, when the compressed spring 129 is restored, the pin 133 can be moved toward the first end 135 along the wall surface 160 of the first portion 158, and can be easily brought to rest against the wall surface 138. Similarly, when the compressed spring 129 is restored, the pin 133 can be moved toward the first end 143 along the wall surface 163 of the second portion 161 and can be easily brought to rest against the wall surface 146.

In this embodiment, a plane including the wall surfaces 159 and 160 of the first part 158 and a plane including the wall surfaces 162 and 163 of the second part 161 are parallel to the center line O of the first rod 104. Accordingly, when the spring 129 is restored, the pin 133 can be moved toward the first end portions 135, 143, and can be easily brought to rest against the wall surfaces 138, 146. Furthermore, when the pin 133 is located at the second ends 136 and 144, it is easier to obtain a reaction force that rotates the first rod 104 relative to the first fork 101 in cooperation with the shift check mechanism 170 (described later). Become.

The explanation will be given by returning to FIG. 3. The first teeth 43 of the drive gear 41 (first gear) include high teeth 43a and regular teeth 43b having a shorter tooth length than the high teeth 43a. The high teeth 43a and the regular teeth 43b are arranged alternately in the circumferential direction. The first tooth 43 includes a third surface 44 facing one circumferential direction, and a fourth surface 45 opposite the third surface 44 and facing the other circumferential direction. The third surface 44 faces the first surface 86 of the first ring 81 , and the fourth surface 45 faces the second surface 87 of the first ring 81 .

The first surface 86 and the third surface 44 are inclined to generate a thrust that causes the drive gear 41 and the first ring 81 to separate in the axial direction in accordance with the torque in the direction that brings the first surface 86 and the third surface 44 into contact. It is a surface. The third surface 44 is inclined toward the fourth surface 45 as it goes away from the drive gear 41 . The angle of inclination of the third surface 44 with respect to a virtual plane (not shown) parallel to the central axis O is the same as the angle of inclination α of the first surface 86.

The second surface 87 and the fourth surface 45 are surfaces where the drive gear 41 and the first ring 81 are not separated from each other in the axial direction when the second surface 87 and the fourth surface 45 are brought into contact with each other to transmit torque. . In this embodiment, the fourth surface 45 is a surface parallel to the central axis O.

The second teeth 53 of the drive gear 51 (second gear) include high teeth 53a and regular teeth 53b having a shorter tooth length than the high teeth 53a. The high teeth 53a and the regular teeth 53b are arranged alternately in the circumferential direction. The second tooth 53 includes a third surface 54 facing one circumferential direction, and a fourth surface 55 opposite the third surface 54 and facing the other circumferential direction.

The second ring 82 includes second dog teeth 93 and 94 protruding from one end surface of the second ring 82 . The second dog tooth 93 is longer than the second dog tooth 94 in the axial direction. The second dog teeth 93 and the second dog teeth 94 are arranged alternately in the circumferential direction. The second dog teeth 93, 94 include a first surface 95 facing one side in the circumferential direction, and a second surface 96 opposite to the first surface 95 and facing the other side in the circumferential direction. There is. The first surface 95 is an inclined surface that is inclined with respect to a virtual plane (not shown) parallel to the central axis O. The second surface 96 is a surface parallel to the central axis O. The first surface 95 is inclined so that it approaches a second surface 96 as it moves away from the second ring 82 in the axial direction. The first surface 95 faces the third surface 54 of the drive gear 51, and the second surface 96 faces the fourth surface 55 of the drive gear 51.

The first surface 95 and the third surface 54 are inclined to generate a thrust that causes the drive gear 51 and the second ring 82 to separate in the axial direction in response to a torque in a direction that brings the first surface 95 and the third surface 54 into contact. It is a surface. The third surface 54 is inclined toward the fourth surface 55 as it goes away from the drive gear 51. The angle of inclination of the third surface 54 with respect to a virtual plane (not shown) parallel to the central axis O is the same as the angle of inclination α of the first surface 95.

The second surface 96 and the fourth surface 55 are surfaces where the drive gear 51 and the second ring 82 are not separated from each other in the axial direction when the second surface 96 and the fourth surface 55 are brought into contact to transmit torque. . In this embodiment, the fourth surface 55 is a surface parallel to the central axis O.

The third tooth 63 of the drive gear 61 (third gear) includes high teeth 63a and regular teeth 63b having a shorter tooth length than the high teeth 63a. The high teeth 63a and the regular teeth 63b are arranged alternately in the circumferential direction. The third tooth 63 includes a third surface 64 facing one circumferential direction, and a fourth surface 65 opposite the third surface 64 and facing the other circumferential direction. The third surface 64 faces the first surface 90 of the first ring 81 , and the fourth surface 65 faces the second surface 91 of the first ring 81 .

The first surface 90 and the third surface 64 are inclined to generate a thrust that causes the drive gear 61 and the first ring 81 to be separated in the axial direction according to the torque in the direction that brings the first surface 90 and the third surface 64 into contact. It is a surface. The third surface 64 is inclined toward the fourth surface 65 as it goes away from the drive gear 61 . The angle of inclination of the third surface 64 with respect to a virtual plane (not shown) parallel to the central axis O is the same as the angle of inclination α of the first surface 90.

The second surface 91 and the fourth surface 65 are surfaces where the drive gear 61 and the first ring 81 are not separated from each other in the axial direction when the second surface 91 and the fourth surface 65 are brought into contact to transmit torque. . In this embodiment, the fourth surface 65 is a surface parallel to the central axis O.

The shift check mechanism 170 includes a first recess 171, a second recess 172, and a third recess 173 formed in the first rod 104, and a ball 174 that hits one of the first recess 171, second recess 172, and third recess 173. and a spring (coil spring) 175 that presses the ball 174 against the first rod 104. Ball 174 and spring 175 are attached to case C (see FIG. 1). The shift check mechanism 170 is also provided on the second rod 106 and the third rod 108. The shift check mechanism 170 of the second rod 106 and the third rod 108 has the same configuration as the shift check mechanism 170 of the first rod 104, so the same reference numerals are given and a description thereof will be omitted.

The shift check mechanism 170 positions the first rod 104 during gear shifting. The ball 174 is pressed into the first recess 171 at the neutral position. The ball 174 is pressed into the third recess 173 when the first dog teeth 84 and 85 engage with the first tooth 43 . The ball 174 is pressed into the second recess 172 when the third dog teeth 88 and 89 engage with the third tooth 63.

FIG. 6(a) is a plan view of the first rod 104 viewed from the direction of arrow VIa in FIG. In FIG. 6(a), illustration of the ball 174 and the spring 175 is omitted. FIG. 6(b) is a cross-sectional view of the first rod 104 taken along line VIb-VIb in FIG. 6(a). In FIG. 6(b), the first rod 104 is illustrated together with the ball 174.

The first recess 171 is a recess extending in the circumferential direction of the first rod 104 . The edge 176 of the first recess 171 has an elliptical shape. The first recess 171 includes two slopes 177 facing each other in the axial direction. A ball 174 is pressed against two slopes 177.

A straight line 178 located at an equal distance from the two slopes 177 of the first recess 171 obliquely intersects a plane 179 perpendicular to the central axis O of the first rod 104. The first recess 171 is formed by β≧tan ⁻¹ μ, where β is the angle between a virtual plane (not shown) including the straight line 178 and the plane 179, and μ is the coefficient of friction between the slope 177 and the ball 174. satisfy. Thereby, when the first rod 104 moves in the axial direction, the ball 174 that presses the slope 177 can move inside the first recess 171 against the frictional force.

When the rod 104 moves to the left in FIG. 6(a) and the ball 174 moves inside the first recess 171 toward the second recess 172, the angle β formed by the slope 177 causes the first rod 104 to move toward the first recess 172. direction (arrow I direction). Further, when the ball 174 moves inside the first recess 171 toward the third recess 173, the first rod 104 rotates in the second direction (arrow II direction) due to the angle β formed by the slope 177.

The length of the first recess 171, which is the length of a line segment having both ends at the intersection of the straight line 178 and the edge 176, is longer than the diameter of the ball 174. The first recess 171 does not restrict the movement of the ball 174 pressed against the slope 177 along the straight line 178 until the ball 174 comes into contact with the edge 176, so the ball 174 moves between the two slopes 177 along the slope 177. can.

Note that the upper limit of the length of the first recess 171 and the angle β formed by the slope 177 is such that the pin 133 passes between the wall surfaces 140 and 148 of the first ends 135 and 143 of the elongated hole 121 in the circumferential direction in the neutral region 114. Even if the first rod 104 moves in the axial direction due to the axial force generated by the slope 177 against which the ball 174 is pressed when the first rod 104 rotates relative to the first fork 101 within the range in which the first rod 104 can move. , the first ring 81 is set so as not to mesh with the drive gears 41, 61.

The second recess 172 and the third recess 173 are conical recesses having the same size and shape. The shape of the edge 181 of the second recess 172 and the shape of the edge 185 of the third recess 173 are petal-shaped. The center 182 of the second recess 172 and the center 186 of the third recess 173 are located on both sides of the center 180 of the first recess 171 in the circumferential direction. The second recess 172 and the third recess 173 are located on both sides of the first rod 104 defined by a plane 179. In this embodiment, the center 182 of the second recess 172 is shifted in the first direction (arrow I direction) with respect to the center 180 of the first recess 171, and the center 186 of the third recess 173 is shifted from the center 180 of the first recess 171. It is shifted in the second direction (direction of arrow II) with respect to the center 180 of.

The virtual plane including the straight line 178 is inclined at an angle β (0°<β<90°) with respect to the plane 179 perpendicular to the first rod 104, and the direction in which the virtual plane is inclined with respect to the plane 179 (counterclockwise in the figure) rotation) is the direction in which the center 182 of the second recess 172 is shifted in the circumferential direction of the first rod 104 with respect to the center 180 of the first recess 171 (counterclockwise in the figure) when viewed from the direction in which the ball 174 is pressed. This is the same as the direction in which the center 186 of the third recess 173 is displaced from the center 180 of the first recess 171 in the circumferential direction of the first rod 104 (counterclockwise in the figure).

As a result, when the first rod 104 moves in the axial direction with the ball 174 being pressed against the slope 177 of the first recess 171, a force in the rotational direction is generated on the slope 177 of the first recess 171, so that the first rod 104 can be rotated. As a result, the position of the pin 133 at the first ends 135, 143 of the elongated hole 121 in the rotational direction can be changed, so that the pin 133 can be prevented from restricting the movement of the first rod 104 in the axial direction.

6(c) is a cross-sectional view of the first rod 104 taken along line VIc-VIc in FIG. 6(a), and FIG. 6(d) is a cross-sectional view of the first rod 104 taken along line VId-VId in FIG. 6(a). It is a diagram. In FIGS. 6(c) and 6(d), the first rod 104 is illustrated together with the ball 174.

As shown in FIGS. 6(c) and 6(d), when the ball 174 is pressed against the center 182 of the second recess 172, the ball 174 comes into contact with the axially facing slopes 182 of the second recess 172, A gap is created between the ball 174 and the circumferential slope 184 of the second recess 172 facing each other. Thereby, the first rod 104 can be positioned in the axial direction when the ball 174 is pressed against the center 182 of the second recess 172. When the first rod 104 is in this position, the pin 133 is located in the second portion 142 of the elongated hole 121.

From this state, when the rod 104 moves to the right in FIG. A gap is created between one side and the ball 174, and the ball 174 contacts the circumferential slope 184 of the second recess 172. The slope angle and depth of the petal-shaped second recess 172 are set so that the ball 174 comes into contact with the circumferential slope 184 of the second recess 172 and then moves to the first recess 171. By pressing the ball 174 against the slope 184, it is possible to easily generate a moment that rotates the first rod 104 in the second direction (arrow II direction).

Further, since the circumferential length of the second recess 172 (the circumferential length of the edge 181 along the outer peripheral surface of the first rod 104) is greater than or equal to the axial length of the second recess 172, the second recess 172 By pressing the ball 174 against the ball 172, a moment that rotates the first rod 104 in the second direction (arrow II direction) is likely to be generated.

From this state, when the rod 104 further moves to the right in FIG. 6(a), the ball 174 moves from the second recess 172 to the first recess 171. When the rod 104 further moves in the axial direction, the first rod 104 rotates in the first direction (direction of arrow I) due to the angle β formed by the slope 177 of the first recess 171 against which the ball 174 is pressed.

When the rod 104 further moves in the axial direction and the ball 174 moves from the first recess 171 to the third recess 173, the ball 174 contacts the circumferential slope 188 of the third recess 173. When the rod 104 moves further in the axial direction, the ball 174 comes into contact with one side of the axial slope 183 of the third recess 173 . Since the slope angle and depth of the petal-shaped third recess 173 are set so that the ball 174 initially contacts the circumferential slope 188 of the third recess 173, by pressing the ball 174 against the slope 188, It is possible to easily generate a moment that rotates the first rod 104 in the first direction (arrow I direction).

When the ball 174 is pressed against the center 186 of the third recess 173, although not shown, the slopes 187 of the third recess 173 facing each other in the axial direction are similar to when the ball 174 is pressed against the center 182 of the second recess 172. The ball 174 comes into contact with the ball 174, and a gap is created between the ball 174 and the circumferential slope 188 of the third recess 173 facing each other. Thereby, the first rod 104 can be positioned in the axial direction when the ball 174 is pressed against the center 186 of the third recess 173. When the first rod 104 is in this position, the pin 133 is located in the first portion 134 of the elongated hole 121.

Further, since the circumferential length of the third recess 173 (the circumferential length of the edge 185 along the outer peripheral surface of the first rod 104) is greater than or equal to the axial length of the third recess 173, the third recess 173 By pressing the ball 174 against the ball 173, a moment that rotates the first rod 104 in the first direction (arrow I direction) is likely to be generated.

FIG. 7 is a perspective view of the shift device 70. FIG. 8 is a sectional view of the shift device taken along line VIII-VIII in FIG. 7. FIG. 9 is a front view of the shift device 70 seen from the direction of arrow IX in FIG. 7 to 9, illustrations of the shift device 70 other than the first rod 104, the second rod 106, and the shift drum 110, and the illustrations of the first cam groove and the second cam groove of the shift drum 110 are omitted. ing. The first rod 104, the second rod 106, and the rail 194 are not shown on both sides in the axial direction.

As shown in FIG. 7, the shift device 70 includes first arms 190 and 197 arranged on the first rod 104 and the second rod 106, respectively, and a rail 194 arranged along the shift drum 110. . The first arm 190 is provided with a first engaging portion 105 that engages with the first cam groove 111 (see FIG. 3). The first arm 190 is provided integrally with a cylindrical attachment portion 191 attached to the first rod 104.

As shown in FIG. 8, the first rod 104 is formed with a hole 192 whose width in the circumferential direction increases as it goes radially outward from the center line O of the first rod 104. A pin 193 that is inserted into a hole 192 is arranged in the mounting portion 191 . The pin 193 passes through the center line O of the first rod 104. Near the center line O of the first rod 104, the diameter of the hole 192 is approximately the same as the thickness of the pin 193. The size of the hole 192 in the axial direction of the first rod 104 (direction perpendicular to the plane of FIG. 8) is approximately the same as the thickness of the pin 193. Therefore, although the attachment part 191 cannot move in the axial direction of the first rod 104, it can rotate around the first rod 104 by a certain angle until the pin 193 is regulated by the hole 192.

Thereby, the first arm 190 is arranged on the first rod 104 so as to be swingable in the circumferential direction of the first rod 104. The relative rotation size of the first rod 104 with respect to the first arm 190 allows the first rod 104 to rotate enough to allow the pin 133 to move in the circumferential direction in the elongated hole 121 (see FIG. 5(a)). It is large enough to

The explanation will be returned to FIG. 7. The rail 194 is a rod-shaped member whose both ends are fixed to the case C of the transmission 1 (see FIG. 1). The rail 194 is arranged parallel to the rotation axis 118 of the shift drum 110.

As shown in FIG. 9, the first arm 190 extends radially outward of the first rod 104 so that the tip 190a of the first arm 190 approaches the shift drum 110. A hole 195 passing through the first arm 190 is formed in the first arm 190 approximately midway between the distal end 190a of the first arm 190 and the attachment portion 191. The orientation of the hole 195 is parallel to the first rod 104. A rail 194 passes through the hole 195. Therefore, the first rod 104 and the first arm 190 can move in the axial direction without being restricted by the rail 194.

The outer portion 196 of the first arm 190 is located radially outward of the first rod 104 . Outer portion 196 includes the inner surface of hole 195 and is located between rail 194 and shift drum 110.

Since the first engaging portion 105 is provided on the first arm 190 that is disposed on the first rod 104 so as to be swingable in the circumferential direction of the first rod 104, the Even if the first rod 104 rotates in the direction in which the first engaging portion 105 is separated, the first arm 190 rotates relatively, and the first engaging portion 105 can be held in the first cam groove 111. Therefore, the first engaging portion 105 may fall off from the first cam groove 111, or the contact area between the first cam groove 111 and the first engaging portion 105 may become smaller, causing the first cam groove 111 or the first engaging portion to fall off. Wear of the portion 105 can be prevented.

When the first arm 190 swings in the direction in which the tip 190a of the first arm 190 moves away from the shift drum 110, the outer portion 196 of the first arm 190 hits the rail 194, and further swinging of the first arm 190 is restricted. Ru. This prevents the first engaging portion 105 from falling off from the first cam groove 111, and the contact area between the first cam groove 111 and the first engaging portion 105 becoming smaller, which prevents the first cam groove 111 and the first engaging portion from falling off. Abrasion of the joint portion 105 can be prevented.

Since the rail 194 passes through the hole 195 of the first arm 190, when the first arm 190 swings in the direction in which the tip 190a of the first arm 190 approaches the shift drum 110, the inner surface of the hole 195 of the first arm 190 Upon hitting the rail 194, further swinging of the first arm 190 is restricted. This can prevent the first engaging portion 105 from being pressed against the bottom of the first cam groove 111 and preventing the shift drum 110 from rotating smoothly.

In the second rod 106, a first arm 197 is swingably provided on the second rod 106 by a mounting portion 191, similarly to the first arm 190. The first arm 197 extends radially outward of the second rod 106 such that the tip 197a of the first arm 197 approaches the shift drum 110. A second engaging portion 107 that engages with the second cam groove 112 (see FIG. 3) is provided on the first arm 197. The first arm 197 is provided with a contact portion 197b that contacts the outer peripheral surface 119 of the shift drum 110. The width of the contact portion 197b in a direction parallel to the rotating shaft 118 of the shift drum 110 is larger than the width of the second cam groove 112 (see FIG. 3). Therefore, the contact portion 197b can be prevented from entering the second cam groove 112. Thereby, the second rod 106 and the first arm 197 can move in the axial direction without the first arm 197 being restricted by the second cam groove 112.

The first arm 197 is provided with an outer portion 198 that includes a tip 197a of the first arm 197. Outer portion 198 is located between rail 194 and shift drum 110. The outer portion 198 is provided with a recess 199 that contacts the rail 194 .

When the first arm 197 swings in the direction in which the tip 197a of the first arm 197 moves away from the shift drum 110, the outer portion 198 of the first arm 197 hits the rail 194, and further swinging of the first arm 197 is restricted. Ru. This prevents the second engaging portion 107 from falling off from the second cam groove 112, and the contact area between the second cam groove 112 and the second engaging portion 107 becoming smaller, which prevents the second cam groove 112 and the second engaging portion from falling off. Abrasion of the joint portion 107 can be prevented.

Further, when the first arm 197 swings in the direction in which the tip 197a of the first arm approaches the shift drum 110, the contact portion 197b of the first arm 197 hits the outer peripheral surface 119 of the shift drum 110, preventing further swinging. limited. This can prevent the second engaging portion 107 from being pressed against the bottom of the second cam groove 112 and preventing the shift drum 110 from rotating smoothly. Further, wear of the second engaging portion 107 and the second cam groove 112 can be prevented.

Since one rail 194 limits the relative rotation of the two first arms 190 and 197, the number of rails can be reduced compared to the case where a rail is provided for each first arm, and the number of parts can be reduced. , the space occupied by the rail inside the case C (see FIG. 1) of the transmission 1 can be reduced.

With reference to FIGS. 10 to 14, the operation of the transmission 1 when changing gears (upshifting) to a high speed gear will be described. In this embodiment, a shift from the 4th gear 40 to the 5th gear 50 will be explained as an example, but since the operation of shifting to other gears is the same, the operation of upshifting and downshifting of other gears will be explained below. The explanation will be omitted.

FIG. 10 is a schematic diagram of the transmission 1 during drive driving in a low gear (4th gear 40). FIG. 11 is a schematic diagram of the transmission 1 during coasting in a low gear. In FIGS. 10 to 14, the rotation direction of the drive gears 41, 51, 61, the first ring 81, and the second ring 82 is downward (in the direction of arrow R) along the plane of the paper. The rotation direction of the shift drum 110 is upward (direction of arrow S) along the plane of the paper. The second surfaces 87 and 96 of the first ring 81 and the second ring 82 face each other in the rotation direction of the first ring 81 and the second ring 82 .

When the shift drum 110 is rotated and the first engagement portion 105 moves from the neutral area 114 of the shift drum 110 to the first engagement area 115, the first rod 104 and the first fork 101 are connected to the drive gear 41 (first gear). The first dog teeth 84 and 85 of the first ring 81 mesh with the first teeth 43 of the drive gear 41. In the neutral region 114, the elastic force of the spring 129 (see FIG. 4) is not applied to the first fork 101, so vibrations of the spring 129 and the like are not transmitted to the first fork 101. In this state, the first fork 101 is fixed to the first rod 104 without wobbling, so that the positional accuracy of the first fork 101 as the first rod 104 moves can be ensured.

When the first rod 104 moves so that the first dog teeth 84 and 85 of the first ring 81 mesh with the first teeth 43 of the drive gear 41, the ball 174 moves along the slope 177 toward the third recess 173. 1 moves inside the recess 171. The first rod 104 rotates in the second direction (arrow II direction) due to the angle β formed by the slope 177 against which the ball 174 is pressed. When the ball 174 climbs over the first recess 171 and presses against the third recess 173, the first rod 104 further rotates in the second direction (arrow II direction). Accordingly, the pin 133 rotates in the second direction (arrow II direction), and the pin 133 hits the wall surface 140 of the first end 135 of the first portion 134 of the elongated hole 121 .

Note that before the first dog teeth 84 and 85 of the first ring 81 come into contact with the first tooth 43 of the drive gear 41, the third recess 173 is pressed against the ball 174, and the third recess 173 is pressed against the first portion 134 of the elongated hole 121. The angle β of the first recess 171 and the position of the third recess 173 are set so that the pin 133 is located. As a result, the first ring 81 is moved toward the drive gear 41 by the axial movement of the first rod 104 and the first fork 101, and the first dog teeth 84, 85 of the first ring 81 are moved toward the drive gear 41. 1 tooth 43.

Similarly, when the third dog teeth 88, 89 of the first ring 81 are engaged with the third teeth 63 of the drive gear 61 (see FIG. 3), the third dog teeth 88, 89 of the first ring 81 are engaged with the third teeth 63 of the drive gear 61 (see FIG. The angle β of the first recess 171 and the third The position of the second recess 172 is set. As a result, the first ring 81 is moved toward the drive gear 61 by the axial movement of the first rod 104 and the first fork 101, and the third dog teeth 88, 89 of the first ring 81 are moved toward the third dog teeth 88, 89 of the drive gear 61. It can mesh with three teeth 63.

As shown in FIG. 10, during drive driving in which power is transmitted from the driving gear 41 to the driven gear 42 (see FIG. 1), the second surface 87 of the first ring 81 is in contact with the fourth surface 45 of the driving gear 41. There is. At this time, a circumferential gap is created between the first surface 86 and the third surface 44. When the second surface 87 and the fourth surface 45 are brought into contact to transmit torque, no thrust force is applied to separate the drive gear 41 and the first ring 81 in the axial direction. The gear is prevented from coming off by limiting the axial movement of the engaging portion 105, the friction between the second surface 87 and the fourth surface 45, and the elastic force due to the preload of the spring 129 (see FIG. 4), thereby reducing the drive torque. introduce.

As shown in FIG. 11, during coasting when power is transmitted from the driven gear 42 of the fourth gear 40 (see FIG. 1) to the drive gear 41, the drive gear 41 rotates faster than the first ring 81, so the drive gear 41 rotates faster than the first ring 81. The third surface 44 of 41 is in contact with the first surface 86 of the first ring 81 . At this time, a circumferential gap is created between the second surface 87 and the fourth surface 45.

The first surface 86 and the third surface 44 generate a thrust that causes the drive gear 41 and the first ring 81 to separate in the axial direction according to the torque during coasting. The thrust causes the first fork 101 to move in the axial direction, and the pin 133 hits the wall surface 138 of the first end 135, thereby restricting the axial movement of the attachment portion 120. This limits the axial movement of the first fork 101 with respect to the first rod 104. Therefore, the engagement between the first dog teeth 84 and 85 of the first ring 81 and the first tooth 43 of the drive gear 41 is maintained, and the first surface 86 of the first ring 81 contacts the third surface 44 of the drive gear 41. The state is maintained.

Note that the first rod 104 moves in the axial direction by an axial gap between the first cam groove 111 of the shift drum 110 and the first engaging portion 105. Since the ball 174 is pressed against the conical surface of the third recess 173 of the first rod 104, the movement of the first rod 104 in the axial direction causes the first rod 104 to rotate slightly, causing the pin in the elongated hole 121 to rotate. The circumferential position of 133 changes.

FIG. 12 is a schematic diagram of the transmission 1 in the initial stage when switching from a low gear (fourth gear 40) to a high gear (fifth gear 50). FIG. 13 is a schematic diagram of the transmission 1 in the middle period when switching from a low gear to a high gear. FIG. 14 is a schematic diagram of the transmission 1 at the final stage of switching from a low gear to a high gear.

As shown in FIG. 12, when the shift drum 110 is rotated and the first engaging portion 105 moves from the first engagement area 115 of the shift drum 110 to the release area 116 during driving in a low gear (4th gear 40), Since the first ring 81, which presses the second surface 87 against the fourth surface 45 and transmits the driving torque, cannot move in the axial direction, the retaining ring 125 (see FIG. 4) of the first rod 104 compresses the spring 129. Then, the first rod 104 moves to the neutral position. This creates a gap between the convex portion 123 of the cylindrical portion 122 and the elastic body 128.

At this time, the ball 174 moves from the third recess 173 to the first recess 171. When the ball 164 moves from the third recess 173 to the first recess 171 along the slope 177. The first rod 104 rotates in the first direction (direction of arrow I) due to the angle β formed by the slope 177 against which the ball 174 is pressed.

When the first engagement part 105 is located in the first engagement area 115 of the shift drum 110, the pin 133 is in contact with the wall surface 140 of the first end 135 of the first part 134 of the elongated hole 121, but the first rod 104 The rotation and axial movement of pin 133 causes first portion 134 to move toward second end 136 . Although the pin 133 approaches the axial wall surface 139 of the second end portion 136, there is an axial gap between the pin 133 and the wall surface 139. Thereby, the relative movement of the first fork 101 in the axial direction can be prevented from being restricted. On the other hand, the second rod 106 does not move in the axial direction while the second engaging part 107 is located in the holding part 112a that keeps the second rod 106 in the neutral position in the release area 116 of the second cam groove 112.

As shown in FIG. 13, when the shift drum 110 is further rotated, the second engaging part 107 moves to the inclined part 112b of the release area 116 of the second cam groove 112, and the second rod 106 moves in the axial direction. do. As a result, the second fork 102 moves toward the drive gear 51 (second gear), and the second dog teeth 93 and 94 of the second ring 82 approach the drive gear 51.

Note that before the second dog teeth 93 and 94 of the second ring 82 come into contact with the second tooth 53 of the drive gear 51, the second recess 172 is pressed against the ball 174 and the second portion 142 of the elongated hole 121 is pressed. The angle β of the first recess 171 and the position of the second recess 172 are set so that the pin 133 is located. As a result, the second ring 82 moves toward the drive gear 51 due to the axial movement of the second rod 106 and the second fork 102, and the tip of the second dog tooth 93 of the second ring 82 moves toward the drive gear 51. It touches the tip of the second tooth 53. Since the second dog teeth 93 of the second ring 82 have a longer tooth length than the second dog teeth 94, the second dog teeth 93 can easily mesh with the high teeth 53a of the drive gear 51.

In a state where the first tooth 43 of the drive gear 41 (first gear) and the first dog teeth 84, 85 of the first ring 81 are engaged, the second tooth 53 of the drive gear 51 (second gear) and the second ring When the second dog teeth 93 of 82 are engaged, the drive gear 51 rotates faster than the drive gear 41, so the fourth speed side is in a coasting state and the fifth speed side is in a drive state.

As shown in FIG. 14, in the fourth gear 40, the first surface 86 of the first ring 81 and the third surface 44 of the drive gear 41 are in a coasting state, and the first surface 86 and the third surface 44 are in contact with each other. The inclination angle α generates a thrust force that separates the drive gear 41 and the first ring 81 in the axial direction depending on the torque. Due to the thrust, the first ring 81 is rotated so that the teeth 92 formed on the inner circumferential surface of the first ring 81 are fitted into the grooves 75 formed on the outer circumferential surface of the first hub 71 (see FIG. 2). The first fork 101 moves in the axial direction while transmitting torque. At this time, the spring 129 (see FIG. 4) is restored and the convex portion 123 approaches the elastic body 128.

When the first ring 81 is separated from the drive gear 41, even if there is a radial gap between the teeth 92 and the groove 75, the axially extending portion of the groove 75 is in the axially extending portion of the tooth 92. Since the first ring 81 is in contact with the first hub 71, the first ring 81 becomes difficult to tilt with respect to the first hub 71, and the moment of force of the first ring 81 can be suppressed. This can suppress the friction of the teeth 92 that rub against the grooves 75 and move in the axial direction. As a result, it is possible to suppress noise and vibration caused by the internal circulation torque being released when the first ring 81 separates from the drive gear 41.

When the spring 129 (see FIG. 4) is restored and the convex portion 123 hits the elastic body 128, and the pin 133 hits the wall surface 138 of the first end 135 of the first part 134 of the elongated hole 121, the first fork 101 The axial movement stops and the first ring 81 is set to the neutral position. Impact is generated by changes in kinetic energy and elastic energy of the spring 129 when the convex portion 123 hits the elastic body 128 and the pin 133 hits the wall surface 138.

However, since it is the first fork 101 and the first ring 81 that have moved in the axial direction, the mass of the first rod 104 is greater than when the entire movement of the first rod 104, first fork 101, and first ring 81 is stopped. The change in kinetic energy can be reduced by the amount that is not included. Furthermore, since the spring 129 buffers the impact, it is possible to suppress the noise and vibrations that occur due to the impact. Furthermore, since the elastic body 128 absorbs changes in the elastic energy of the spring 129, it is possible to further suppress noise and vibration caused by impact.

Further, since the movement of the first fork 101 and the first ring 81 is stopped by applying the pin 133 to the wall surface 138 of the first end 135 of the first part 134 of the elongated hole 121, the movement of the first fork 101 and the first ring 81 is stopped. Compared to the case where only the spring 129 is stationary, the elastic force required for the spring 129 can be suppressed. Thereby, the space required for the spring 129 to be displaced can be reduced. Further, since the force applied to the spring 129 to obtain the elastic force of the spring 129 can be reduced, the motor (not shown) for rotating the shift drum 110 can be made smaller. Therefore, the spring 129 can be easily assembled, and the transmission 1 can be prevented from increasing in size.

The movement of the first fork 101 and the first ring 81 is stopped when the pin 133 hits the wall surface 138 of the elongated hole 121, so the first ring 81 is separated from the drive gear 41 and the first fork 101 reaches the neutral position. , it is possible to prevent the driver from approaching the drive gear 61 (third gear) beyond that position. Therefore, it is possible to prevent double meshing in which the second dog teeth 93 and 94 mesh with the second tooth 53 of the drive gear 51 and the third dog teeth 88 and 89 mesh with the third tooth 63 of the drive gear 61. .

On the other hand, the fifth speed gear 50 is in a drive state in which the second surface 96 of the second ring 82 and the fourth surface 55 of the drive gear 51 are in contact, and the drive gear 51 and the second ring 82 are separated in the axial direction. No thrust is generated. Therefore, the second rod 106 moves in the axial direction as the second engaging portion 107 is guided by the inclined portion 112b of the second cam groove 112, and the second fork 102 and the second ring 82 are moved closer to the drive gear 51. As they approach, the second dog teeth 93, 94 of the second ring 82 and the second teeth 53 of the drive gear 51 become more deeply engaged.

When the meshing becomes deeper, friction occurs between the second surface 96 of the second ring 82 and the fourth surface 55 of the drive gear 51. However, since a preload is applied to the spring 129 (see FIG. 4) disposed on the second rod 106, as the second rod 106 moves, it resists the friction between the second surface 96 and the fourth surface 55. The second fork 102 can be moved to deepen the engagement.

In the release area 116 of the shift drum 110, before setting the axial position of the second rod 106 so that the second dog teeth 93, 94 mesh with the second teeth 53 by the inclined portion 112b of the second cam groove 112. , the axial position of the first rod 104 begins to be set so that the first dog teeth 84 and 85 meshing with the first tooth 43 are disengaged. As a result, the elastic force of the spring 129 can be prevented from canceling out the axial thrust generated between the first surface 86 and the third surface 44. Therefore, the engagement between the first tooth 43 and the first dog teeth 84, 85 can be easily released. In particular, in the release area 116 of the shift drum 110, after the first rod 104 is set to the neutral position so as to release the engagement of the first dog teeth 84, 85 that engage the first teeth 43, the second dog teeth 93, 94 are set to the neutral position. Since the axial position of the second rod 106 is set so as to mesh with the second tooth 53, the meshing between the first tooth 43 and the first dog teeth 84, 85 can be more easily released.

When the shift drum 110 is further rotated and the first engaging part 105 and the second engaging part 107 move to the second engagement area 117 of the shift drum 110, the first rod 104 is maintained at the neutral position and the second rod 106 is maintained at the meshing position between the second ring 82 and the drive gear 51.

As described above, in the transmission 1, when shifting from a low gear to a high gear, the first dog teeth 84 and 85 of the first ring 81 mesh with the first teeth 43 of the first gear constituting the lower gear, and When the second dog teeth 93 and 94 of the second ring 82 mesh with the second tooth 53 of the second gear constituting the gear stage, due to internal circulation torque, the force of The first ring 81 coupled to the first gear, which rotates slowly, is pushed out in the axial direction by the thrust generated between the first surface 86 and the third surface 44.

As a result, the elastic force required of the spring 129 can be suppressed by the amount of the thrust generated between the first surface 86 and the third surface 44 while achieving a so-called seamless shift, which is a shift that suppresses interruptions in the driving torque. Further, the movement of the first fork 101 and the first ring 81 is stopped when the pin 133 hits the wall surface 138 of the elongated hole 121. The spring 129 buffers the impact when the first ring 81 and the first fork 101 move and stop in the axial direction due to the thrust generated between the first surface 86 and the third surface 44 . Therefore, the shock of shifting can be suppressed.

A shift device 200 in a second embodiment will be described with reference to FIGS. 15 and 16. The shift device 200 is arranged in the transmission 1 instead of the shift device 70 in the first embodiment. Note that the same parts as those described in the first embodiment are given the same reference numerals, and the following description will be omitted. FIG. 15 is a perspective view of a shift device 200 in the second embodiment. FIG. 16 is a front view of shift device 200 viewed from the direction of arrow XVI in FIG. 15. In FIGS. 15 and 16, illustrations other than the first rod 104 and the shift drum 110 and illustrations of the first cam groove of the shift drum 110 are omitted. The illustration of both sides of the first rod 104 in the axial direction is omitted.

Shift device 200 includes a first arm 201 and a second arm 202. Like the first arm 190 in the first embodiment, the first arm 201 is swingably disposed on the first rod 104 by a mounting portion 191. The second arm 202 is provided integrally with the first arm 201. In this embodiment, the second arm 202 is branched from the first arm 201.

The first arm 201 extends radially outward of the first rod 104 so that the tip 201a of the first arm 201 approaches the shift drum 110. A first engaging portion 105 that engages with the first cam groove 111 (see FIG. 3) is provided on the first arm 201.

The second arm 202 branches approximately perpendicularly to the first arm 201 from a position approximately midway between the tip 201 a of the first arm 201 and the attachment portion 191 . Second arm 202 extends toward shift drum 110. The second arm 202 is provided with a contact portion 203 that contacts the outer peripheral surface 119 of the shift drum 110 . The width of the contact portion 203 in a direction parallel to the rotating shaft 118 of the shift drum 110 is larger than the width of the first cam groove 111 (see FIG. 3). Therefore, the contact portion 203 can be prevented from entering the first cam groove 111. Thereby, the first rod 104 and the first arm 201 can move in the axial direction without the second arm 202 being restricted by the first cam groove 111.

The contact portion 203 is a line of intersection between the outer circumferential surface 119 of the shift drum 110 and a virtual plane 206 passing through the center axis of the first rod 104 and the center axis of the shift drum 110 . 207, it touches both sides of the outer circumferential surface 119 in the circumferential direction. The contact portion 203 is divided into a first portion 204 and a second portion 205 with an intersection line 206 as a boundary.

When the first arm 201 swings, the second arm 202 provided integrally with the first arm 201 also swings. When the first arm 201 swings in the direction in which the tip 201a of the first arm 201 moves away from the shift drum 110, the first portion 204 of the contact portion 203 of the second arm 202 hits the outer circumferential surface 119 of the shift drum 110, and oscillation is restricted. Therefore, the first engaging part 105 may fall off from the first cam groove 111, or the contact area between the first cam groove 111 and the first engaging part 105 may become smaller, causing the first cam groove 111 or the first engaging part 105 to fall off. Wear of the portion 105 can be prevented.

Further, when the first arm 201 swings in the direction in which the tip 201a of the first arm 201 approaches the shift drum 110, the second portion 205 of the contact portion 203 of the second arm 202 hits the outer circumferential surface 119 of the shift drum 110. Further swinging is restricted. This can prevent the first engaging portion 105 from being pressed against the bottom of the first cam groove 111 and preventing the shift drum 110 from rotating smoothly.

Although the present invention has been described above based on the embodiments, the present invention is not limited to these embodiments in any way, and it is easily understood that various improvements and modifications can be made without departing from the spirit of the present invention. This can be inferred. For example, the number and arrangement of gear stages of the transmission 1, the shape of the cam grooves 111 and 112 formed in the shift drum 110, the number and shape of the grooves 75 formed in the first hub 71, the number and shape of the grooves 75 formed in the first ring 81, etc. The number and shape of the teeth 92 can be set as appropriate.

In the embodiment, a case has been described in which the elongated hole 121 is formed in the first fork 101 and the pin 133 is fixed to the first rod 104, but the present invention is not necessarily limited to this. On the contrary, it is naturally possible to fix a pin to the first fork 101 and form a long hole in the first rod 104. In this case as well, the same effects as in this embodiment can be achieved.

In the embodiment, a case has been described in which the second ends 136, 144 are provided in the elongated holes 121, 150, 157, but the present invention is not necessarily limited to this. When the first part 134, 151, 158 or the second part 142, 154, 161 of the elongated hole 121, 150, 157 is connected to the axial edge of the mounting part 120, the first part 134, 151, The second end 136 or second portion 142, 154, 161 of 158 is omitted.

In the embodiment, the fourth surface 45 of the first tooth 43 provided on the drive gear 41, the fourth surface 55 of the second tooth 53 provided on the drive gear 51, and the first dog tooth provided on the first ring 81. Although the case has been described in which the second surfaces 87 of the teeth 84 and 85 and the second surfaces 96 of the second dog teeth 93 and 94 provided on the second ring 82 are surfaces parallel to the central axis O, this is not necessarily the case. It is not limited to. When the second surfaces 87, 96 and the fourth surfaces 45, 55 are in contact and transmitting torque, the axial component of the force due to the torque and the second surfaces 87, 96, the fourth surfaces 45, 55, It is sufficient that the resultant force of the axial component of the frictional force with 55 does not act in a direction that separates the first ring 81 and the second ring 82 from the drive gears 41 and 51. As long as this relationship is satisfied, the second surfaces 87, 96 and the fourth surfaces 45, 55 may be inclined with respect to a virtual plane (not shown) parallel to the central axis O.

In the embodiment, the third surface 44 of the first tooth 43 provided on the drive gear 41 and the first surface 86 of the first dog teeth 84 and 85 provided on the first ring 81 are used to drive according to the torque. Although a case has been described in which a thrust generating section is configured to generate a thrust that separates the gear 41 and the first ring 81 in the axial direction, the present invention is not necessarily limited to this. For example, as in the transmission described in Japanese Unexamined Patent Application Publication No. 2012-127471, the inclination angle of the first surface 86 and the third surface 44 is made almost zero, and instead of the teeth 92 provided on the first ring 81, the first A cylindrical projection is provided on the ring 81, and instead of the parallel groove 75 provided on the first hub 71, a V-shaped cam groove that is inclined with respect to the plane containing the central axis O is provided on the outer peripheral surface of the first hub 71. Of course, it is possible to form the first ring 81 into a cam groove and arrange the protrusion of the first ring 81 in the cam groove. Even when the cam groove of the first hub 71 and the protrusion of the first ring 81 are used as thrust generating parts, the same effects as in this embodiment can be achieved.

In the embodiment, a case has been described in which the spring 129 is a compression coil spring, but the spring 129 is not necessarily limited to this. It is of course possible to use a spring other than a coil spring for the spring 129.

In the embodiment, a case has been described in which the elastic body 128 is interposed between the washer 127 and the convex portion 123, and the elastic body 131 is interposed between the spacer 130 and the attachment portion 120. Of course, one can be omitted. Even without the elastic bodies 128 and 131, the spring 129 can buffer the impact. Furthermore, it is naturally possible to arrange the elastic body 131 between the spacer 130 and the washer 126.

In the embodiment, a case has been described in which the transmission of drive torque is switched between the drive gears 41 and 51 disposed on the drive shaft 2, but the present invention is not necessarily limited to this. Switching the transmission of driving torque between the driven gear 12 arranged on the driven shaft 3 and the driving gear 21, or switching the transmission of the driving torque between the driven gear 32 arranged on the driven shaft 3 and the driving gear 41. In this case, the same effects as in this embodiment can be achieved. In these cases, similarly to the embodiment, the gear that constitutes the low speed gear is the first gear, and the gear that constitutes the high speed gear is the second gear.

In the embodiment, in order to allow the first arms 190, 201 to swing relative to the first rod 104, a hole 192 is formed in the first rod 104, and a pin 193 is fixed to the mounting portion 191 of the first arm 190, 201. Although the description has been made for the case where Of course, it is possible to form a hole in the attachment portion 191 and fix a pin placed in the hole to the first rod 104. In this case as well, the first arms 190 and 210 can be arranged to be swingable relative to the first rod 104.

The means for making the first arms 190, 201 swingable relative to the first rod 104 is not limited to connecting the first rod 104 and the mounting portion 191 with holes or pins. For example, it is naturally possible to interpose a bearing between the first rod 104 and the attachment part 191 so that the first arms 190, 201 can swing relative to the first rod 104.

In the embodiment, a case has been described in which the first arm 190 is arranged on the first rod 104 and the first arm 197 is arranged on the second rod 106, but the invention is not necessarily limited to this. It is of course possible to arrange the first arm 197 on the first rod 104.

In the embodiment, a case has been described in which the second arm 202 branches from the first arm 201, but the invention is not necessarily limited to this. It is of course possible to provide the second arm 202 on the mounting portion 191 in addition to the first arm 201.

In the embodiment, a case has been described in which the width of the contact portions 197b, 203 in the direction parallel to the rotating shaft 118 of the shift drum 110 is larger than the width of the cam grooves 111, 112, but the present invention is not limited to this. Of course, it is possible to provide portions of the contact portions 197b, 203 that do not fit into the cam grooves 111, 112 to prevent the contact portions 197b, 203 from entering the cam grooves 111, 112.

In the embodiment, a case has been described in which the transmission 1 is installed in a car, but the invention is not limited to this, and it is of course possible to install the transmission 1 in a construction machine, an industrial vehicle, an agricultural machine, or the like. In this case as well, the transmission 1 can eliminate interruptions in the drive torque during gear changes. As a result, idle rotation of the drive shaft 2 can be eliminated and fuel efficiency can be improved.

1 Transmission 2 Drive shaft (shaft)
3 Driven shaft (shaft)
41 Drive gear (1st gear)
43 1st tooth 61 Drive gear (3rd gear)
63 Third tooth 70,200 Shift device 71 First hub 81 First ring 84,85 First dog tooth 88,89 Third dog tooth 101 First fork 104 First rod 105 First engaging portion 110 Shift drum 111 No. 1 Cam groove 119 Outer peripheral surface of shift drum 121, 150, 157 Elongated hole 129 Spring 133 Pin 134, 151, 158 First part 135 First end 142, 154, 161 Second part 143 First end 190, 201 1 arm 194 rail 195 hole 196, 198 outer part 202 2nd arm 203 contact part 206 virtual plane 207 line of intersection

Claims (4)

a first gear disposed on the shaft, forming a predetermined gear stage, and having first teeth on an end surface in the axial direction;
a third gear, which constitutes a gear stage different from the gear stage constituted by the first gear, is disposed on the shaft, and has third teeth provided on an end surface in the axial direction;
a shift device that selectively couples the first gear and the third gear to the shaft,
The shift device includes a first annular hub coupled to the shaft;
first dog teeth arranged on the outer periphery of the first hub, rotatably engageable with the first hub and movable in the axial direction, and meshing with the first teeth, provided on an axial end surface; a first ring provided with third dog teeth that mesh with the third teeth on the other end surface;
a first fork attached to the first ring;
a shift drum in which a first cam groove is formed;
A transmission comprising: a first rod in which a first engaging portion that engages with the first cam groove is disposed, and that moves the first fork in the axial direction along the first cam groove;
comprising a rail disposed along the shift drum,
The shift device includes a spring that is interposed between the first rod and the first fork and biases the first fork in the axial direction by an elastic force;
an elongated hole extending in the axial direction formed in one of the first rod and the first fork;
a pin fixed to the other of the first rod and the first fork and arranged in the elongated hole;
a first arm provided with the first engagement portion and disposed on the first rod so as to be swingable in a circumferential direction of the first rod;
The elongated hole has a first portion extending in the axial direction from a first end thereof;
comprising a first end connected to the first end of the first part, and a second part extending in the axial direction from the first end;
The first portion and the second portion have first ends connected to each other in the circumferential direction and extend on opposite sides in the axial direction ,
The rail is in contact with an outer portion of the first arm located on the outer side of the first rod in the radial direction,
The outer portion is located between the rail and the shift drum . the outer portion includes an inner surface of a hole formed in the first arm and parallel to the first rod;
2. The transmission of claim 1 , wherein said rail passes through said hole. a first gear disposed on the shaft, forming a predetermined gear stage, and having first teeth on an end surface in the axial direction;
a third gear, which constitutes a gear stage different from the gear stage constituted by the first gear, is disposed on the shaft, and has third teeth provided on an end surface in the axial direction;
a shift device that selectively couples the first gear and the third gear to the shaft,
The shift device includes a first annular hub coupled to the shaft;
first dog teeth arranged on the outer periphery of the first hub, rotatably engageable with the first hub and movable in the axial direction, and meshing with the first teeth, provided on an axial end surface; a first ring provided with third dog teeth that mesh with the third teeth on the other end surface;
a first fork attached to the first ring;
a shift drum in which a first cam groove is formed;
A transmission comprising: a first rod in which a first engaging portion that engages with the first cam groove is disposed, and that moves the first fork in the axial direction along the first cam groove;
The shift device includes a spring that is interposed between the first rod and the first fork and biases the first fork in the axial direction by an elastic force;
an elongated hole extending in the axial direction formed in one of the first rod and the first fork;
a pin fixed to the other of the first rod and the first fork and arranged in the elongated hole;
a first arm provided with the first engagement portion and disposed on the first rod so as to be swingable in a circumferential direction of the first rod;
The elongated hole has a first portion extending in the axial direction from a first end thereof;
comprising a first end connected to the first end of the first part, and a second part extending in the axial direction from the first end;
The first part and the second part have first ends connected to each other in the circumferential direction and extend on opposite sides in the axial direction ,
a second arm provided integrally with the first arm and extending toward the shift drum;
The second arm includes a contact portion that contacts the outer peripheral surface of the shift drum,
The contact portion includes an intersection line between the outer peripheral surface of the shift drum and a virtual plane passing through the central axis of the first rod and the central axis of the shift drum, on the outer peripheral surface of the shift drum. Transmission tangent to the containing position . The transmission according to claim 3 , wherein the contact portion contacts both sides of the outer peripheral surface in the circumferential direction with respect to the line of intersection.

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