JP7288975B2 - transmission - Google Patents

Description

The present invention relates to transmissions.

A first gear arranged on a shaft and provided with a first tooth on its axial end face, and a gear step higher than the gear step formed by the first gear, arranged on the shaft and having a second tooth on its axial end face. Transmissions are known that have a second gear provided and a shifter that selectively couples the first gear and the second gear to the shaft. The transmission disclosed in Patent Document 1 includes an annular first hub and a second hub that are coupled to a shaft, and an annular hub that is arranged on the outer periphery of the first hub and can be engaged with the first hub in the rotational direction and axially. A first ring that engages with the first teeth, comprising a first ring that is movable and a second ring that is arranged on the outer periphery of the second hub and is rotationally engageable with the second hub and is axially movable. A dog tooth is provided on the axial end face of the first ring, and a second dog tooth meshing with the second tooth is provided on the axial end face of the second ring.

In this transmission, the first dog tooth meshes with the first tooth, and when switching from a low gear stage driven by the first gear to a high gear stage driven by the second gear, the first tooth meshes with the first dog tooth. The first ring is moved in the direction to release the . As a result, it is possible to achieve a so-called seamless shift that suppresses interruptions in drive torque.

However, when the first tooth and the first dog tooth are disengaged, the shift rod fixing the shift fork, the shift fork attached to the first ring, and the first ring move together. The impact is large when the shifted shift fork and first ring are stopped.

Therefore, the applicant disposes a spring between the shift rod and the shift fork, moves the shift rod first when disengaging the first tooth and the first dog tooth, and then uses the elastic force of the spring. A patent application was filed for an invention in which a shift fork and a first ring are moved and a spring absorbs an impact when the shifted shift fork and first ring stand still (Patent Document 2, which was not published at the time of this filing).

JP 2012-127471 A PCT/JP2019/48876

However, in the technique of Patent Document 2, the spring receives all the shocks that stop the shift fork and the first ring, so there is a problem that a spring with a large elastic force must be used. If a spring with a large elastic force is used, the space required for the spring to be displaced increases, and the force applied to the spring in order to obtain a large elastic force increases, resulting in poor assembly.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and it is an object of the present invention to provide a transmission capable of achieving a seamless shift while suppressing the elastic force required for the springs.

In order to achieve this object, the transmission of the present invention comprises: a first gear arranged on a shaft to constitute a predetermined gear stage and having a first tooth provided on an end face in the axial direction; and a gear stage constituted by the first gear. a second gear arranged on a shaft and provided with a second tooth on an axial end face thereof, and a third gear arranged on the shaft and provided with a third tooth on an axial end face thereof; a shift device selectively coupling the first gear, the second gear and the third gear to the shaft, the shift device comprising annular first and second hubs coupled to the shaft; A first dog tooth that is arranged on the outer periphery and is rotatably engageable and axially movable with respect to the first hub and that meshes with the first tooth is provided on the axial end face, and a third dog tooth is provided on the other end face. A first ring provided with third dog teeth that mesh with the teeth, and a first ring that is arranged on the outer periphery of the second hub and is rotatably engageable and axially movable with respect to the second hub and meshes with the second teeth. A second ring having a second dog tooth provided on an end face in the axial direction, a first fork attached to the first ring, a second fork attached to the second ring, a first cam groove and a second cam groove. a first rod having a formed shift drum, a first engaging portion that engages with the first cam groove, and axially moving the first fork along the first cam groove; a second rod having a second engaging portion to engage and axially moving the second fork along the second cam groove, the shift drum moving the first rod and the second rod to a neutral position; and the axial position of the second rod is set so that the second dog tooth meshes with the second tooth, and the first rod disengages the first dog tooth meshing with the first tooth a release area for setting the axial position of the shift device, the shift device being interposed between the first rod and the first fork and biasing the first fork axially by elastic force in the release area. an axially extending slot formed in one of the first rod and the first fork; and a pin fixed to the other of the first rod and the first fork and arranged in the slot, the slot has a first end with a pin in the neutral region and extends axially from the first end with a pin in the release region; a second portion having one end and extending axially from the first end, the first and second portions being circumferentially connected at the first ends and axially opposite one another; The center position of the second portion in the circumferential direction is shifted in the first direction in the circumferential direction with respect to the center position of the first portion in the circumferential direction.

According to the transmission of claim 1, the release region of the shift drum sets the axial position of the second rod so that the second dog tooth meshes with the second tooth, and the first dog meshes with the first tooth. The axial position of the first rod is set to disengage the teeth. A spring interposed between the first rod and the first fork axially biases the first fork with elastic force in the release area. A seamless shift can thus be achieved.

A slot is formed in one of the first rod and the first fork, and a pin fixed to the other of the first rod and the first fork is arranged inside the slot. The first and second parts of the slot are circumferentially connected at first ends and extend axially opposite to each other. The center position of the second portion in the circumferential direction is displaced in the first direction in the circumferential direction with respect to the center position of the first portion in the circumferential direction. The pin resides at a first portion in the release area and at a first end in the neutral area. As a result, the first fork and the first ring, which have moved due to the restoration of the spring, can be stopped by applying the pin to the first end of the first part, so that the elastic force required for the spring can be suppressed.

According to the transmission of claim 2, the wall surface of the first end of the second part in the first direction and the wall surface of the first end of the first part in the second direction opposite to the first direction. , increases toward the radially outer side of the first rod. Thereby, in addition to the effect of claim 1, it is possible to ensure the magnitude of relative rotation of the first rod with respect to the first fork in the neutral region.

According to the transmission of claim 3, the shift check mechanism presses the ball against the first concave portion of the first rod in the neutral region, and when the first dog tooth meshes with the first tooth, the third gear of the first rod is pushed. A ball is pressed against the recess, and the ball is pressed against the second recess of the first rod when the third dog tooth meshes with the third tooth. The centers of the second recess and the third recess are located on both sides of the first rod in the circumferential direction with respect to the center of the first recess. A torsional moment is generated in 1 rod. Therefore, in addition to the effect of claim 1 or 2, the pin moved along the first portion or the second portion can be easily stopped at the first end portion.

According to the transmission of claim 4, when the ball is pressed against the center of the second recess, the pin is positioned in the second portion, so that coast torque is generated when the third tooth and the third dog tooth are in mesh. When force is applied and a force is generated from the third tooth in the direction in which the third dog tooth comes off, the elongated hole limits the movement of the pin and prevents the third dog tooth from coming off. Further, when the ball is pressed against the center of the third recess, the pin is positioned in the first portion, so that coast torque is applied when the first tooth and the first dog tooth are engaged, and the first tooth moves from the first tooth to the first dog tooth. When a force is generated in the direction in which the dog teeth come off, the elongated hole limits the movement of the pin and prevents the first dog teeth from coming off. Since the spring does not need to receive the force in the direction in which the dog tooth is pulled out, the elastic force required for the spring can be further reduced in addition to the effect of claim 3.

According to the transmission of claim 5, the circumferential length of the second recess is greater than or equal to the axial length of the second recess, and the circumferential length of the third recess is the axial length of the third recess. is greater than or equal to the length of Therefore, in addition to the hardening of claim 3 or 4, it is possible to easily generate a torsional moment in the first rod by pressing the ball against the second recess and the third recess.

According to the transmission of claim 6, when the first rod moves in the axial direction from the state in which the ball presses the first recess and the ball presses the second recess, the first rod presses the second recess in the circumferential direction. The ball touches the slope of Further, when the first rod moves in the axial direction and the ball presses the third recess from the state where the ball presses the first recess, the ball first comes into contact with the slope in the circumferential direction of the third recess. Therefore, in addition to the effect of any one of claims 3 to 5, it is possible to make it easier to generate a moment in the first rod.

According to the transmission of claim 7, when the ball is pressed against the center of the second recess, the ball contacts the axial slope of the second recess. Further, when the ball is pressed against the center of the third recess, the ball comes into contact with the axial slope of the third recess. Therefore, in addition to the effect of any one of claims 3 to 6, it is possible to easily position the first rod in the axial direction.

According to the transmission of claim 8, the first recess comprises two slopes facing axially to each other, and the ball can move along the slopes between the two slopes. Therefore, in addition to the effect of any one of claims 3 to 7, the first rod can be rotated when the ball presses the first concave portion.

According to the transmission of claim 9, the imaginary plane containing straight lines equidistant from the two slopes of the first recess forms an angle β (0°<β<90) with respect to the plane perpendicular to the first rod. °), and the direction in which the imaginary plane inclines with respect to the plane is the direction in which the center of the second recess is displaced from the center of the first recess in the circumferential direction of the first rod when viewed from the direction in which the ball is pressed. It is the same as the direction in which the center of the third recess is shifted in the circumferential direction of the first rod with respect to the center of the first recess. As a result, when the first rod moves in the axial direction while the ball is pressed against the slope of the first recess, a rotational force is generated on the slope of the first recess, so that the first rod can be rotated. . As a result, since the position of the pin at the first end can be changed in the rotational direction, in addition to the effect of claim 8, the pin can be prevented from restricting the movement of the first rod in the axial direction.

When the angle β formed between a virtual plane including a straight line equidistant from the two slopes and the plane perpendicular to the first rod and the friction coefficient μ between the slope and the ball, the first recess is β≧tan. ^-1 μ. This prevents the first rod from becoming unable to move due to friction between the slope and the ball.

According to the transmission of claim 10, the angle .beta. It is set at an angle where the pin is positioned at the part. Therefore, in addition to the effect of claim 9, the movement of the pin can be prevented from being restricted by the first rod.

1 is a skeleton diagram of a transmission in one embodiment; FIG. 4 is a perspective view of a first hub with a first ring disposed thereon; FIG. 1 is a schematic diagram of a transmission in which a first rod and a second rod are in a neutral position; FIG. FIG. 4 is a cross-sectional view of the first rod on which the first fork is arranged; (a) is a plan view of a long hole viewed from the direction of arrow Va in FIG. 4, (b) is a plan view of a long hole in a modified example, and (c) is a plan view of a long hole in another modified example. is. (a) is a plan view of the first rod viewed 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(a) is a cross-sectional view of the first rod taken along the line VIc-VIc of FIG. 6(a), and FIG. 6(d) is a cross-sectional view of the first rod taken along the line VId-VId of FIG. 6(a); FIG. 4 is a schematic diagram of the transmission during low-speed driving. FIG. 4 is a schematic diagram of a transmission during coasting in a low-speed stage; FIG. 4 is a schematic diagram of an initial transmission that switches from a low speed stage to a high speed stage; It is a schematic diagram of the transmission of the middle stage which switches from a low-speed stage to a high-speed stage. FIG. 4 is a schematic diagram of the transmission at the final stage of switching from a low speed stage to a high speed stage;

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. First, referring to FIG. 1, a schematic configuration of a transmission 1 of the present invention will be described. FIG. 1 is a skeleton diagram of a transmission 1 according to one embodiment. A transmission 1 includes a drive shaft 2 to which power is input and a driven shaft 3 arranged parallel to the drive shaft 2 , and an output gear 4 is arranged on the driven shaft 3 . The drive shaft 2 and the driven shaft 3 support a 1st gear 10, a 2nd gear 20, a 3rd gear 30, a 4th gear 40, a 5th gear 50 and a 6th gear 60, which constitute a plurality of gear stages. In this embodiment, the transmission 1 is mounted on an automobile (not shown).

The first speed gear 10 includes a drive gear 11 fixed to the drive shaft 2 so as not to rotate relative thereto, and a driven gear 12 fixed to the driven shaft 3 so as to rotate relative to the drive gear 11 while constantly meshing with the drive gear 11 . The second speed 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 rotate relative to it, and a driven gear 32 fixed to the driven shaft 3 so as to rotate relative to the drive gear 31 while constantly meshing with the drive gear 31 .

The fourth speed 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 constantly meshing with the drive gear 41 . The fifth speed 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 sixth speed 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 constantly meshing with the drive gear 61 .

Transmission 1 further includes a shift device 70 for selectively coupling gears to drive shaft 2 and 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, A first rod 104 , a second rod 106 , a third rod 108 and a shift drum 110 are provided.

The first hub 71 is an annular member arranged 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 arranged 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 arranged between the driven gear 12 and the driven gear 32 and coupled to the driven shaft 3 .

A first tooth 43 that protrudes axially toward the first hub 71 is provided on the axial end face of the drive gear 41 . A third tooth 63 that protrudes axially toward the first hub 71 is provided on the axial end face of the drive gear 61 . A second tooth 53 that protrudes axially toward the second hub 72 is provided on the axial end face of the drive gear 51 . A fourth tooth 23 axially protruding toward the second hub 72 is provided on the axial end face of the drive gear 21 . An axial end face of the driven gear 12 is provided with a fifth tooth 13 protruding axially toward the third hub 73 . A sixth tooth 33 axially protruding toward the third hub 73 is provided on the axial end face of the driven gear 32 .

The first ring 81, the second ring 82, and the third ring 83 are rotationally engageable and axially movably connected 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. First dog teeth 84 and 85 (see FIG. 3) that axially protrude toward the drive gear 41 and first dog teeth that axially protrude toward the drive gear 61 are formed on the axial end face of the first ring 81 . Three dog teeth 88, 89 (see FIG. 3) are provided.

On the axial end face of the second ring 82 , second dog teeth 93 and 94 (see FIG. 3 ) axially protruding toward the drive gear 51 and second dog teeth axially protruding toward the drive gear 21 are provided. Four dog teeth 97, 98 (see FIG. 3) are provided. A fifth dog tooth (not shown) axially protruding toward the driven gear 12 and a sixth dog tooth axially protruding toward the driven gear 32 are formed on the axial end face of the third ring 83 . (not shown) are 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 having a first cam groove 111, a second cam groove 112, and a third cam groove 113 extending in the circumferential direction. The shift drum 110 is rotatably fixed to the case C and rotated around its central axis by a motor (not shown). A first engaging portion 105 arranged on the first rod 104 engages with the first cam groove 111 , and a second engaging portion 107 arranged on the second rod 106 engages with the second cam groove 112 . A third engaging portion 109 arranged on the third rod 108 engages with the third cam groove 113 .

The shift drum 110 rotates based on an operation signal of a shift lever (not shown) or based on an accelerator opening and a vehicle speed signal by operating 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 axially via the first rod 104 , the second rod 106 and the third rod 108 . As the first fork 101, the second fork 102 and the 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 described with reference to FIG. 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, description of the second hub 72, the third hub 73, the second ring 82 and the third ring 83 is omitted.

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

The first ring 81 has first dog teeth 84, 85 protruding from one end face along the central axis O of the first ring 81, and third dog teeth 88, 89 protruding axially from the other end face. , is equipped with A 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 axially longer than the first dog tooth 85 , and the third dog tooth 88 is axially longer than the third dog tooth 89 . The first dog teeth 84 are alternately arranged with the first dog teeth 85 in the circumferential direction, and the third dog teeth 88 are alternately arranged with the third dog teeth 89 in the circumferential direction.

The first dog teeth 84, 85 have a first surface 86 facing one of the circumferential directions, and a second surface 87 opposite to the first surface 86 and facing the other circumferential direction. there is The third dog teeth 88 and 89 have a first surface 90 facing one of the circumferential directions and a second surface 91 opposite to the first surface 90 and facing the other 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. As shown in FIG. The second surfaces 87 and 91 are surfaces parallel to the central axis O. As shown in FIG. The first surfaces 86 , 90 are inclined so as to approach the second surfaces 87 , 91 respectively as they move away from the first ring 81 in the axial direction.

Teeth 92 parallel to the central axis O are provided on the inner surfaces of the first dog tooth 84 and the third dog tooth 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 , but the first ring 81 does not move on the first hub 71 . Cannot rotate around.

FIG. 3 is a schematic diagram of the transmission 1 with the first rod 104 and the second rod 106 in the neutral position. In FIG. 3, illustration of the third cam groove 113 of the shift drum 110 and the driving gear 21 is omitted. Positioning the first engaging portion 105 and the second engaging portion 107 respectively engaging with the first cam groove 111 and the second cam groove 112 of the shift drum 110 in the neutral region 114 of the shift drum 110 allows the first The rod 104 and the second rod 106 are set at the neutral position.

A spring 129 (see FIG. 4) is arranged between the first rod 104 and the first fork 101 to bias the first fork 101 in the axial direction by means of elastic force. Similarly, between the second rod 106 and the second fork 102, and between the third rod 108 and the third fork 103, the second fork 102 and the third fork 103 are axially biased by elastic force. A spring (not shown) is positioned. The structure in which springs are arranged between the second rod 106 and the second fork 102 or between the third rod 108 and the third fork 103 is such that the spring 129 is arranged between the first rod 104 and the first fork 101. Since the structure is the same as that of

FIG. 4 is a cross-sectional view of the first rod 104 on which the first fork 101 is arranged 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 portion 120 of the first fork 101 is formed in a tubular shape and is attached to the outer circumference of the first rod 104 . A long hole 121 is formed in the mounting portion 120 so as to penetrate in the thickness direction and extend in the axial direction. The tubular portion 122 surrounds the outer circumference of the first rod 104 with a gap from the first rod 104 . One end of the tubular portion 122 is coupled to the mounting portion 120 . A convex portion 123 (stopper) that protrudes radially inward is provided at the other end portion of the tubular 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 positioned inside the tubular portion 122 . Washers 126 and 127 having outer diameters larger than the outer diameters 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 axially spaced apart from each other inside the tubular portion 122 .

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 positioned 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. The elastic force of the preloaded spring 129 presses the washer 126 against the snap ring 124 and the washer 127 against the snap 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 mounting portion 120 . The static spring constants of elastic bodies 128 and 131 are smaller than the static spring constant of spring 129 .

The mounting portion 120, the elastic body 131, the spacer 130, and the washer 126 are arranged without gaps, and the washer 127, elastic body 128, and protrusion 123 are arranged without 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 between the elastic body 128 and the projection 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 looseness. Since the restoration 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 (mounting 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 mounting portion 120 is arranged. A pin 133 is fixed in the hole 132 and the end of the pin 133 is arranged in the slot 121 . The first rod 104 can rotate relative to the mounting portion 120 of the first fork 101 by the amount of the circumferential gap between the pin 133 and the elongated hole 121 .

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

The first ends 135 and 143 of the elongated hole 121 are portions that overlap each other in the circumferential direction. The second end portions 136 and 144 are arc-shaped portions formed by the second end portions 136 and 144 on the outer peripheral surface of the mounting portion 120 . The first end portions 135 and 143 of the first portion 134 and the second portion 142 are connected to each other in the circumferential direction of the mounting portion 120, and the second end portions 136 and 144 are axially opposite to each other. The center position of the second portion 142 in the circumferential direction is displaced from the center position of the first portion 134 in the circumferential direction in the first circumferential direction (arrow I direction). The pin 133 is located at the first ends 135, 143 when the first rod 104 is in the neutral position.

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

In addition, 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 spring-loaded until the pin 133 hits the axial wall surface 147 of the second end portion 144 of the second portion 142 . 129 can be compressed and axially moved relative to the first fork 101 . When the compressed spring 129 is restored, the pin 133 rests against the axial wall 146 of the first end 143 .

The wall surface 148 of the first end portion 143 of the second portion 142 in the first direction (arrow I direction) and the first end portion 135 of the first portion 134 in the second direction opposite to the first direction (arrow II direction) ) increases from the center line O of the first rod 104 toward the outside in the radial direction (the front side of the paper surface). 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 (direction of arrow I) of the middle portion 145 of the second portion 142 is smoothly connected to a wall surface 148 in the first direction of the first end portion 143 of the second portion 142 , and the middle portion of the first portion 134 A wall surface 141 in the second direction (direction of arrow II) of the portion 137 smoothly connects to a wall surface 140 in the second direction of the first end portion 135 of the first portion 134 . As a result, when the compressed spring 129 is restored, the pin 133 can be easily moved along the wall surface 141 of the first portion 134 toward the first end portion 135 and rested against the wall surface 138 . Similarly, when the compressed spring 129 is restored, the pin 133 can be moved along the wall 149 of the second portion 142 toward the first end 143 to help rest against the wall 146 .

In this embodiment, the plane including the wall surfaces 140 and 141 of the first portion 134 and the plane including the wall surfaces 148 and 149 of the second portion 142 are parallel to the center line O of the first rod 104 (not at the twisted position). ). As a result, when the pin 133 is positioned at the second ends 136 and 144, the pin 133 rotates when the first rod 104 rotates with respect to the first fork 101 in cooperation with the shift check mechanism 170 (described later). and the wall surfaces of the second ends 136 and 144 can be suppressed.

FIG. 5(b) is a plan view of the elongated hole 150 in the modified example. The slot 150 has a first portion 151 with a first axial end 135 , a second end 136 and an intermediate portion 137 and a first axial end 143 , a second end 144 and an intermediate portion 145 . a second portion 154 comprising; The second end 136 of the first portion 151 and the second end 144 of the second portion 154 lie on a plane containing the centerline O of the first rod 104 .

The wall surface 155 of the first end portion 143 of the second portion 154 in the first direction (arrow I direction) and the first end portion 135 of the first portion 151 in the second direction opposite to the first direction (arrow II direction) ) increases from the center line O of the first rod 104 toward the radially outer side (front side of the drawing). This makes it easier for the pin 133 to rotate relative to the slot 150 at the first ends 135 and 143 .

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

In this embodiment, a plane including the wall surfaces 152 and 153 of the first portion 151 and a plane including the wall surfaces 155 and 156 of the second portion 154 cross the center line O of the first rod 104 obliquely. As a result, the area of the wall surfaces 138 and 146 in the axial direction of the first end portions 135 and 143 can be made larger than the area of the wall surfaces 138 and 146 in the long hole 121 (see FIG. 5A). Further, when the pin 133 is positioned at the second ends 136 and 144, it is easy to obtain a reaction force to rotate 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 an elongated hole 157 in another modified example. The slot 157 has a first portion 158 with a first axial end 135 , a second end 136 and an intermediate portion 137 and a first axial end 143 , a second end 144 and an intermediate portion 145 . a second part 161 comprising; The second end 136 of the first portion 158 and the second end 144 of the second portion 161 lie on a plane containing the centerline O of the first rod 104 .

The wall surface 162 of the first end portion 143 of the second portion 161 in the first direction (arrow I direction) and the first end portion 135 of the first portion 158 in the second direction opposite to the first direction (arrow II direction) ) increases from the center line O of the first rod 104 toward the radially outer side (front side of 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 .

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

In this embodiment, the plane including the wall surfaces 159 and 160 of the first portion 158 and the plane including the wall surfaces 162 and 163 of the second portion 161 are parallel to the centerline O of the first rod 104 . This facilitates movement of pin 133 toward first ends 135 and 143 and rest against walls 138 and 146 as spring 129 recovers. Furthermore, when the pin 133 is positioned at the second ends 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.

Returning to FIG. 3, description will be made. A first tooth 43 of the drive gear 41 (first gear) includes a high tooth 43a and full teeth 43b having a shorter tooth depth than the high tooth 43a. The high teeth 43a and the full teeth 43b are alternately arranged in the circumferential direction. The first tooth 43 has a third surface 44 facing one direction in the circumferential direction and a fourth surface 45 opposite to the third surface 44 and facing in the other direction in the 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 such that the drive gear 41 and the first ring 81 are separated from each other in the axial direction according to the torque in the direction that the first surface 86 and the third surface 44 are brought into contact with each other. It is the surface. The third surface 44 is inclined so as to approach the fourth surface 45 as it goes away from the drive gear 41 . The inclination angle of the third surface 44 with respect to a virtual plane (not shown) parallel to the central axis O is the same as the inclination angle α of the first surface 86 .

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

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

The second ring 82 has second dog teeth 93 and 94 projecting from one end face of the second ring 82 . The second dog tooth 93 is axially longer than the second dog tooth 94 . The second dog teeth 93 and the second dog teeth 94 are arranged alternately in the circumferential direction. The second dog teeth 93 and 94 have a first surface 95 facing one of the circumferential directions and a second surface 96 opposite to the first surface 95 and facing the other 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. As shown in FIG. The second surface 96 is a surface parallel to the central axis O. As shown in FIG. The first surface 95 is inclined so as to approach the 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 so as to generate a thrust to separate the driving gear 51 and the second ring 82 in the axial direction according to the torque in the direction of contacting the first surface 95 and the third surface 54 . It is the surface. The third surface 54 is inclined so as to approach the fourth surface 55 as it goes away from the driving gear 51 . The inclination angle of the third surface 54 with respect to a virtual plane (not shown) parallel to the central axis O is the same as the inclination angle α of the first surface 95 .

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

A third tooth 63 of the drive gear 61 (third gear) includes a high tooth 63a and full teeth 63b having a shorter tooth depth than the high tooth 63a. The high teeth 63a and the full teeth 63b are alternately arranged in the circumferential direction. The third tooth 63 has a third surface 64 facing in one circumferential direction and a fourth surface 65 opposite to the third surface 64 and facing in 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 such that the drive gear 61 and the first ring 81 are separated from each other in the axial direction according to the torque in the direction that the first surface 90 and the third surface 64 are brought into contact with each other. It is the surface. The third surface 64 is inclined so as to approach the fourth surface 65 as it goes away from the drive gear 61 . The inclination angle of the third surface 64 with respect to a virtual plane (not shown) parallel to the central axis O is the same as the inclination angle α of the first surface 90 .

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

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 any one of the first recess 171, the second recess 172, and the 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 . Since the shift check mechanism 170 for the second rod 106 and the third rod 108 has the same configuration as the shift check mechanism 170 for the first rod 104, the same reference numerals are given and the description thereof is omitted.

The shift check mechanism 170 positions the first rod 104 during shifting. A ball 174 is pressed against the first concave portion 171 at the neutral position. The ball 174 is pressed against the third concave portion 173 when the first dog teeth 84 and 85 mesh with the first tooth 43 . A ball 174 is pressed into the second concave portion 172 when the third dog teeth 88 and 89 mesh 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. Illustration of the ball 174 and the spring 175 is omitted in FIG. 6(a). FIG. 6(b) is a cross-sectional view of the first rod 104 along line VIb--VIb of FIG. 6(a). The first rod 104 is illustrated together with the ball 174 in FIG. 6(b).

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

A straight line 178 equidistant 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 concave portion 171 is defined by β≧tan ⁻¹ μ, where β is the angle formed by the plane 179 and an imaginary plane (not shown) including the straight line 178 , and μ is the coefficient of friction between the slope 177 and the ball 174 . meet. As a result, when the first rod 104 moves axially, the ball 174 pressing against the slope 177 can move inside the first recess 171 against the frictional force.

When the rod 104 moves leftward in FIG. 6A and the ball 174 moves in the first recess 171 toward the second recess 172, the angle β formed by the slope 177 causes the first rod 104 to move to the first position. direction (direction of arrow I). Also, when the ball 174 moves in 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 the 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 along the straight line 178 pressed against the slope 177 until the ball 174 touches the edge 176, so the ball 174 moves along the slope 177 between the two slopes 177. can.

The upper limit of the length of the first recess 171 and the angle β formed by the slope 177 is as follows: 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 movable range. , the drive gears 41 and 61 are set so that the first ring 81 does not mesh with them.

The second recess 172 and the third recess 173 are conical recesses of 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 the plane 179 . In this embodiment, the center 182 of the second recess 172 is shifted in the first direction (direction of arrow I) 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. is displaced in the second direction (arrow II direction) with respect to the center 180 of the .

The imaginary plane including the straight line 178 is inclined by an angle β (0°<β<90°) with respect to the plane 179 that intersects the first rod 104 perpendicularly, and the direction in which the imaginary plane is inclined with respect to the plane 179 (counterclockwise ) is the direction in which the center 182 of the second recess 172 deviates from the center 180 of the first recess 171 in the circumferential direction of the first rod 104 when viewed from the direction in which the ball 174 is pressed (counterclockwise in the figure). and the direction in which the center 186 of the third recess 173 deviates 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 while the ball 174 is pressed against the slope 177 of the first recess 171, a rotational force is generated on the slope 177 of the first recess 171. 104 can be rotated. As a result, the position of the pin 133 in the first ends 135 and 143 of the elongated hole 121 can be changed, so that the pin 133 does not restrict the axial movement of the first rod 104 .

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

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 opposing axial slopes 182 of the second recess 172, A gap is formed between the opposing circumferential slopes 184 of the second recess 172 and the ball 174 . This allows axial positioning of the first rod 104 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 positioned in the second portion 142 of the slot 121 .

From this state, when the rod 104 moves to the right in FIG. A gap is formed between one side and the ball 174 , and the ball 174 is in contact with the slope 184 in the circumferential direction of the second recess 172 . Since the slope angle and depth of the petal-shaped second recess 172 are set so that the ball 174 contacts the circumferential slope 184 of the second recess 172 and then the ball 174 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).

In addition, 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 equal to or greater than the axial length of the second recess 172, the second recess 172 The pressing of ball 174 against 172 tends to generate a moment that rotates first rod 104 in the second direction (the direction of arrow II).

From this state, when the rod 104 moves further to the right in FIG. 6A, the ball 174 moves from the second recess 172 to the first recess 171 . When the rod 104 moves further in the axial direction, the first rod 104 rotates in the first direction (arrow I direction) 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 moves further in the axial direction and the ball 174 moves from the first concave portion 171 to the third concave portion 173 , the ball 174 comes into contact with the circumferential slope 188 of the third concave portion 173 . As 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 first comes into contact with the circumferential slope 188 of the third recess 173, the pressing of the ball 174 against the slope 188 causes A moment that rotates the first rod 104 in the first direction (arrow I direction) can be easily generated.

When the ball 174 is pressed against the center 186 of the third recess 173, similarly to when the ball 174 is pressed against the center 182 of the second recess 172, the axial slopes 187 of the third recess 173 face each other (not shown). A gap is formed between the balls 174 and the inclined surfaces 188 facing each other in the circumferential direction of the third recess 173 . This enables axial positioning of the first rod 104 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 positioned in the first portion 134 of the slot 121 .

In addition, 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 The pressing of the ball 174 against 173 tends to generate a moment that rotates the first rod 104 in the first direction (arrow I direction).

7 to 11, the operation of the transmission 1 when shifting (shifting up) to a high gear will be described. In the present embodiment, shifting from the 4th gear 40 to the 5th gear 50 will be described as an example, but since the operation of shifting to other gears is the same, the upshifting and downshifting operations of other gears will be described. Description is omitted.

FIG. 7 is a schematic diagram of the transmission 1 during driving at a low speed (fourth gear 40). FIG. 8 is a schematic diagram of the transmission 1 during coasting in the low-speed stage. 7 to 11, the rotation directions of the drive gears 41, 51, 61, the first ring 81, and the second ring 82 are downward (arrow R direction) along the paper surface. The direction of rotation of shift drum 110 is upward (in the 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 direction of rotation of the first ring 81 and the second ring 82 .

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

When the first rod 104 moves so that the first dog teeth 84 , 85 of the first ring 81 mesh with the first teeth 43 of the drive gear 41 , the balls 174 move 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 portion 135 of the first portion 134 of the long hole 121 .

Before the first dog teeth 84 and 85 of the first ring 81 come into contact with the first teeth 43 of the driving gear 41, the third concave portion 173 is pressed against the ball 174 and the first portion 134 of the elongated hole 121 is pressed. The angle β of the first recess 171 and the position of the third recess 173 are set so that the pin 133 is positioned. As a result, the axial movement of the first rod 104 and the first fork 101 causes the first ring 81 to move toward the drive gear 41 , and the first dog teeth 84 and 85 of the first ring 81 move toward the first teeth of the drive gear 41 . 1 tooth 43 can be meshed.

Similarly, when the third dog teeth 88, 89 of the first ring 81 are meshed 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 drive gear. The angle β of the first recess 171 and the angle β of the first recess 171 and the third The positions of the two recesses 172 are set. As a result, the axial movement of the first rod 104 and the first fork 101 causes the first ring 81 to move toward the driving gear 61 , and the third dog teeth 88 and 89 of the first ring 81 move toward the driving gear 61 . 3 teeth 63 can be meshed.

As shown in FIG. 7, the second surface 87 of the first ring 81 is in contact with the fourth surface 45 of the driving gear 41 during driving when power is transmitted from the driving gear 41 to the driven gear 42 (see FIG. 1). there is At this time, a circumferential gap is formed between the first surface 86 and the third surface 44 . When the torque is transmitted by bringing the second surface 87 and the fourth surface 45 into contact with each other, no thrust force separates the drive gear 41 from the first ring 81 in the axial direction. The axial movement of the engaging portion 105 is restricted, 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) prevent gear disengagement and increase the drive torque. introduce.

As shown in FIG. 8, during coasting when power is transmitted from the driven gear 42 (see FIG. 1) of the fourth speed gear 40 to the drive gear 41, the drive gear 41 rotates faster than the first ring 81. The third surface 44 of 41 contacts the first surface 86 of the first ring 81 . At this time, a circumferential gap is formed between the second surface 87 and the fourth surface 45 .

The first surface 86 and the third surface 44 generate a thrust that separates the drive gear 41 and the first ring 81 in the axial direction according to the torque during coasting. The thrust force moves the first fork 101 in the axial direction, and the pin 133 comes into contact with the wall surface 138 of the first end portion 135 , thereby restricting the axial movement of the mounting portion 120 . This limits axial movement of the first fork 101 relative to the first rod 104 . Therefore, the meshing between the first dog teeth 84 and 85 of the first ring 81 and the first tooth 43 of the driving gear 41 is maintained, and the first surface 86 of the first ring 81 contacts the third surface 44 of the driving gear 41. state is maintained.

The first rod 104 moves in the axial direction by the amount of the 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 axial movement of the first rod 104 causes the first rod 104 to rotate a little, and the pin in the elongated hole 121 The position of 133 in the circumferential direction changes.

FIG. 9 is a schematic diagram of the transmission 1 at the initial stage of switching from the low speed stage (fourth gear 40) to the high speed stage (fifth gear 50). FIG. 10 is a schematic diagram of the transmission 1 in the middle stage of switching from the low speed stage to the high speed stage. FIG. 11 is a schematic diagram of the transmission 1 at the final stage of switching from the low speed stage to the high speed stage.

As shown in FIG. 9, when the shift drum 110 is rotated during low-speed (fourth gear 40) driving, and the first engagement portion 105 moves from the first engagement region 115 of the shift drum 110 to the release region 116, Since the first ring 81, which transmits the driving torque by pressing the second surface 87 against the fourth surface 45, cannot move in the axial direction, the retaining ring 125 (see FIG. 4) of the first rod 104 compresses the spring 129. As a result, the first rod 104 moves to the neutral position. Thereby, a gap is formed between the convex portion 123 of the tubular 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 (arrow I direction) due to the angle β formed by the slope 177 against which the ball 174 is pressed.

When the first engagement portion 105 is positioned in the first engagement area 115 of the shift drum 110 , the pin 133 contacts the wall surface 140 of the first end portion 135 of the first portion 134 of the slot 121 , but the first rod 104 The rotation and axial movement of the pin 133 moves the first portion 134 towards the second end 136 . The axial wall 139 of the second end 136 is approached by the pin 133 , but there is an axial gap between the pin 133 and the wall 139 . Thereby, the axial relative movement of the first fork 101 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 portion 107 is positioned in the holding portion 112a that holds the second rod 106 in the neutral position in the release area 116 of the second cam groove 112 .

As shown in FIG. 10, when the shift drum 110 is further rotated, the second engaging portion 107 moves to the inclined portion 112b in 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 to the drive gear 51 (second gear), and the second dog teeth 93 and 94 of the second ring 82 approach the drive gear 51 .

Before the second dog teeth 93 and 94 of the second ring 82 come into contact with the second teeth 53 of the driving gear 51, the second concave portion 172 is pressed against the ball 174 and the second portion 142 of the slot 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 positioned. As a result, the axial movement of the second rod 106 and the second fork 102 causes the second ring 82 to move toward the drive gear 51 , and the tips of the second dog teeth 93 of the second ring 82 move toward the drive gear 51 . It touches the tip of the second tooth 53 . Since the second dog tooth 93 of the second ring 82 has a longer tooth depth than the second dog tooth 94, the second dog tooth 93 and the high tooth 53a of the drive gear 51 can be easily meshed.

When 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 with each other, the second tooth 53 of the drive gear 51 (second gear) and the second ring are engaged. When the second dog tooth 93 of 82 meshes, the drive gear 51 rotates faster than the drive gear 41, so that the 4th speed side is in the coast state and the 5th speed side is in the drive state.

As shown in FIG. 11, the fourth speed gear 40 is in a coasting state in which the first surface 86 of the first ring 81 and the third surface 44 of the drive gear 41 are in contact with each other. Due to the inclination angle α, a thrust is generated to separate the drive gear 41 and the first ring 81 in the axial direction according to the torque. The thrust force causes the first ring 81 to move in a state in which the teeth 92 formed on the inner peripheral surface of the first ring 81 are fitted into the grooves 75 formed on the outer peripheral surface of the first hub 71 (see FIG. 2). The first fork 101 moves axially 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 tooth 92 and the groove 75 , the axially extending portion of the tooth 92 overlaps the axially extending portion of the groove 75 . Since the first ring 81 is in contact with the first hub 71, it is difficult for the first ring 81 to tilt, and the moment of force of the first ring 81 can be suppressed. As a result, it is possible to suppress the friction of the tooth 92 that rubs against the groove 75 and moves in the axial direction. As a result, when the first ring 81 separates from the drive gear 41, the noise and vibration caused by the release of the internal circulation torque can be suppressed.

When the spring 129 (see FIG. 4) is restored, the convex portion 123 contacts the elastic body 128, and the pin 133 contacts the wall surface 138 of the first end portion 135 of the first portion 134 of the long hole 121, the first fork 101 Axial movement stops and the first ring 81 is set to the neutral position. When the convex portion 123 hits the elastic body 128 and the pin 133 hits the wall surface 138 , the kinetic energy and the elastic energy of the spring 129 change to generate an impact.

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 movement of the first rod 104, the first fork 101 and the first ring 81 as a whole is stopped. The change in kinetic energy can be reduced by the amount that is not included. Moreover, since the spring 129 absorbs the impact, it is possible to suppress the sound and vibration caused by 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 pressing the pin 133 against the wall surface 138 of the first end portion 135 of the first portion 134 of the elongated hole 121, the first fork 101 and the first ring 81 are prevented from moving. The elastic force required for the spring 129 can be suppressed as compared with the case where only the spring 129 stops the movement of the 81 . This reduces the space required for the spring 129 to be displaced. Further, since the force applied to the spring 129 to obtain the elastic force of the spring 129 can be reduced, the size of the motor (not shown) for rotating the shift drum 110 can be reduced. Therefore, it is possible to facilitate the mounting of the spring 129 and to suppress an increase in the size of the transmission 1 .

Since the movement of the first fork 101 and the first ring 81 is stopped by the pin 133 hitting the wall surface 138 of the long hole 121, the first ring 81 is separated from the driving gear 41 and the first fork 101 reaches the neutral position. , so as not to approach the drive gear 61 (third gear) beyond that position. Therefore, it is possible to prevent double meshing in which the second tooth 53 of the drive gear 51 is meshed with the second dog teeth 93 and 94 and the third tooth 63 of the drive gear 61 is meshed with the third dog teeth 88 and 89. .

On the other hand, the fifth speed gear 50 is in a driven 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 along with the second engaging portion 107 guided by the inclined portion 112b of the second cam groove 112, and the second fork 102 and the second ring 82 move toward the drive gear 51. As a result, the engagement between the second dog teeth 93 and 94 of the second ring 82 and the second tooth 53 of the drive gear 51 deepens.

Friction between the second surface 96 of the second ring 82 and the fourth surface 55 of the drive gear 51 occurs when the engagement becomes deeper. However, since the spring 129 (see FIG. 4) located on the second rod 106 is preloaded, it will resist the friction between the second surface 96 and the fourth surface 55 and, as the second rod 106 moves, The second fork 102 can be moved to deepen the engagement.

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 portions 112 b of the second cam grooves 112 in the release region 116 of the shift drum 110 . , to set the axial position of the first rod 104 so as to release the meshing of the first dog teeth 84 and 85 meshing with the first tooth 43 . As a result, the elastic force of the spring 129 can be prevented from canceling 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 meshing of the first dog teeth 84, 85 meshing with the first tooth 43, the second dog teeth 93, 94 are 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 to move the first engaging portion 105 and the second engaging portion 107 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, the first dog teeth 84, 85 of the first ring 81 mesh with the first teeth 43 of the first gear constituting the low gear stage when shifting from the low speed stage to the high speed stage. When the second dog teeth 93 and 94 of the second ring 82 mesh with the second teeth 53 of the second gear that constitutes the gear stage, the internal circulating torque causes the elastic force of the spring 129 to be different from that of the second gear. The first ring 81 coupled to the slow-rotating first gear is axially pushed out 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 shift that suppresses interruptions in the drive torque, that is, a so-called seamless shift. Furthermore, 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 long hole 121 . The spring 129 absorbs the impact when the first ring 81 and the first fork 101 move axially and stop due to the thrust generated between the first surface 86 and the third surface 44 . Therefore, a shift shock can be suppressed.

Although the present invention has been described above based on the embodiments, the present invention is by no means limited to these embodiments, and it is easily understood that various improvements and modifications are possible without departing from the gist of the present invention. It 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 appropriately set.

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

In the embodiment, the case where the elongated holes 121, 150, 157 are provided with the second ends 136, 144 has been described, but this is not necessarily the case. When the first portions 134, 151, 158 or the second portions 142, 154, 161 of the slots 121, 150, 157 are connected to the axial edges of the mounting portion 120, the first portions 134, 151, The second end 136 of 158 or the second portions 142, 154, 161 are 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 where the second surfaces 87 of 84 and 85 and the second surfaces 96 of the second dog teeth 93 and 94 provided on the second ring 82 are parallel to the central axis O has been described, this is not necessarily the case. is not limited to When the second surfaces 87, 96 and the fourth surfaces 45, 55 are in contact with each other to transmit torque, the axial component of the force due to the torque, the second surfaces 87, 96 and the fourth surfaces 45, 45, The resultant force of the axial component of the frictional force with 55 should not act in the direction of separating the first ring 81 and the second ring 82 from the driving gears 41 and 51 . The second surfaces 87 and 96 and the fourth surfaces 45 and 55 may be inclined with respect to a virtual plane (not shown) parallel to the central axis O as long as this relationship is satisfied.

In this 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 drive according to the torque. 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, but the present invention is not necessarily limited to this. For example, as in the transmission described in Japanese Patent Application Laid-Open No. 2012-127471, the inclination angles of the first surface 86 and the third surface 44 are made substantially 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 grooves 75 provided on the first hub 71 , V-shaped cam grooves inclined with respect to a plane containing the central axis O are formed on the outer peripheral surface of the first hub 71 . , and the protrusion of the first ring 81 is arranged in the cam groove. Even when the cam groove of the first hub 71 and the projection of the first ring 81 are used as the thrust generating portion, the same effect as that of the present embodiment can be achieved.

In the embodiment, the case where the spring 129 is a compression coil spring has been described, but it is not necessarily limited to this. Of course, it is possible to employ a spring other than a coil spring as the spring 129 .

In the embodiment, 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 mounting portion 120. However, at least the elastic bodies 128 and 131 are Of course, it is possible to omit one of them. Even without the elastic bodies 128 and 131, the spring 129 can absorb the impact. Also, it is naturally possible to arrange the elastic body 131 between the spacer 130 and the washer 126 .

In the embodiment, the case of switching the transmission of drive torque between the drive gears 41 and 51 arranged on the drive shaft 2 has been described, but the present invention is not necessarily limited to this. It switches the transmission of driving torque between the driven gear 12 and the driving gear 21 arranged on the driven shaft 3 and switches the transmission of the driving torque between the driven gear 32 arranged on the driven shaft 3 and the driving gear 41. Also in the case of such a case, it is possible to achieve the same effect as that of the present embodiment. In these cases, as in the embodiment, the gear forming the low speed gear is the first gear, and the gear forming the high speed gear is the second gear.

In the embodiment, a case where the transmission 1 is mounted on an automobile has been described, but the present invention is not limited to this, and it is of course possible to mount the transmission 1 on construction machinery, industrial vehicles, agricultural machinery, and the like. In this case as well, the transmission 1 can eliminate the discontinuity of the drive torque at the time of shifting. As a result, idling 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 first tooth 51 driving gear (second gear)
53 second tooth 61 drive gear (third gear)
63 third tooth 70 shift device 71 first hub 72 second hub 81 first ring 82 second ring 84, 85 first dog teeth 88, 89 third dog teeth 93, 94 second dog teeth 101 first fork 102 second 2 forks 104 1st rod 105 1st engagement portion 106 2nd rod 107 2nd engagement portion 110 shift drum 111 first cam groove 112 second cam groove 114 neutral area 116 release area 121, 150, 157 long hole 129 spring 133 Pins 134, 151, 158 First Part 135 First End 140, 152, 159 Wall 142, 154, 161 Second Part 143 First End 148, 155, 162 Wall 170 Shift Check Mechanism 171 First Recess 172 Second 2 recess 173 3rd recess 174 ball 177 slope 178 straight line 179 plane 180 center of first recess 182 center of second recess 183 axial slope 184 circumferential slope 186 third recess center 187 axial slope 188 circumferential direction slope of

Claims (10)

a first gear arranged on a shaft and forming a predetermined gear stage and having a first tooth on an end face in the axial direction;
a second gear that constitutes a gear stage higher than the gear stage constituted by the first gear and that is arranged on the shaft and provided with a second tooth on an end face in the axial direction;
a third gear arranged on the shaft and provided with a third tooth on an end face in the axial direction;
a shift device that selectively couples the first gear, the second gear, and the third gear to the shaft;
The shift device includes an annular first hub and a second hub coupled to the shaft;
a first dog tooth arranged on the outer periphery of the first hub, rotatably engageable and axially movable with respect to the first hub and meshing with the first tooth is provided on an axial end face; a first ring provided with a third dog tooth meshing with the third tooth on the other end face;
A second dog tooth is arranged on the outer periphery of the second hub, is rotatably engageable with the second hub, is axially movable, and meshes with the second tooth, and is provided on the axial end face. a second ring;
a first fork attached to the first ring;
a second fork attached to the second ring;
a shift drum formed with a first cam groove and a second cam groove;
a first rod having a first engaging portion that engages with the first cam groove and axially moving the first fork along the first cam groove;
a second rod having a second engaging portion that engages with the second cam groove and axially moving the second fork along the second cam groove, the transmission comprising:
the shift drum includes a neutral region for setting the first rod and the second rod to neutral positions;
The axial position of the second rod is set so that the second dog tooth meshes with the second tooth, and the first rod is disengaged from the first dog tooth meshing with the first tooth. a release region for setting an axial position;
a spring interposed between the first rod and the first fork and biasing the first fork axially with an elastic force in the release region;
an axially extending slot 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 slot;
the slot having a first end at which the pin resides at the neutral region, a first portion extending axially from the first end at which the pin resides at the release region;
a second portion having a first end connected to the first end of the first portion and extending axially from the first end;
wherein the first end portions of the first portion and the second portion are circumferentially connected to each other and extend axially opposite to each other;
A transmission in which a circumferential center position of the second portion is shifted in a first circumferential direction with respect to a circumferential center position of the first portion. A circumference between a wall surface of the first end of the second part in the first direction and a wall surface of the first end of the first part in the second direction opposite to the first direction 2. The transmission according to claim 1, wherein the directional distance increases toward the radially outer side of the first rod. The shift device includes a first recess, a second recess, and a third recess formed in the first rod;
a ball pressed against one of the first recess, the second recess, and the third recess;
The first recess is pressed against the ball in the neutral region,
The third recess is pressed against the ball when the first dog tooth meshes with the first tooth,
The second recess includes a shift check mechanism that presses the ball when the third dog tooth meshes with the third tooth,
The transmission according to claim 1 or 2, wherein the centers of the second recess and the third recess are located on both sides of the first rod in the circumferential direction with respect to the center of the first recess. when the ball is pressed against the center of the second recess, the pin is positioned in the second portion;
4. A transmission according to claim 3, wherein said pin is located in said first portion when said ball is pressed against the center of said third recess. The circumferential length of the second recess is greater than or equal to the axial length of the second recess, and the circumferential length of the third recess is greater than or equal to the axial length of the third recess. 5. A transmission according to item 3 or 4. When the first rod moves in the axial direction from the state where the ball is pressing against the first recess and the ball presses against the second recess, the ball is first pushed against the slope in the circumferential direction of the second recess. is in contact with
When the first rod moves in the axial direction from the state in which the ball is pressing against the first recess and the ball presses against the third recess, the ball is first pressed against the slope in the circumferential direction of the third recess. 6. A transmission according to any one of claims 3 to 5, wherein the . when the ball is pressed against the center of the second recess, the ball is in contact with the inclined surface of the second recess in the axial direction;
7. The transmission according to any one of claims 3 to 6, wherein when the ball is pressed against the center of the third recess, the ball contacts an axial slope of the third recess. The first recess comprises two inclined surfaces facing in the axial direction,
8. A transmission as claimed in any one of claims 3 to 7, wherein the balls are movable along the ramps between two of the ramps. an imaginary plane containing straight lines equidistant from the two slopes of the first recess is inclined by an angle β with respect to a plane perpendicular to the first rod;
The direction in which the imaginary plane is inclined with respect to the plane is the direction in which the center of the second recess is displaced from the center of the first recess in the circumferential direction of the first rod when viewed from the direction in which the ball is pressed. and the center of the third recess is the same as the direction in which the first rod is circumferentially displaced from the center of the first recess. The angle β is such that the pin is positioned at the first portion when the first dog tooth meshes with the first tooth, and the pin is positioned at the second portion when the third dog tooth meshes with the third tooth. 10. The transmission of claim 9, wherein the pin is set at an angle.

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