JP2000009217A - Synchronizing device for transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronizing device for a transmission exhibiting good lubrication of a sliding section between a shift arm and a sleeve by forming a tapered guide surface at an end of claw of the shift arm. SOLUTION: A claw 23 formed at an end of an arm 22 of a shift arm 20 is fitted in a peripheral groove 19 of a sleeve 17. At the end of the claw 23, a tapered guide surface 27 is formed protrusively. Lubricant L flowing by the rotation accompanied by the sleeve 17 collides with the tapered guide surface 27 and flows along either of inclined surfaces 28 into gaps 24a and 24b formed between a sliding surface 25 of the peripheral groove 19 and both sides of sliding surfaces 26 of the claw 23 to lubricate a sliding part 24, thereby seizure and wear at the sliding part can be prevented and durability of a synchronizing device is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission synchronizing device used for an automobile, a construction machine, a working machine, and the like.

[0002]

2. Description of the Related Art In general, a transmission between two gear ratios in a transmission includes a low-speed gear having a spline clutch rotating integrally with a gear and a high-speed gear having a spline clutch rotating integrally with the gear. A clutch hub that rotates integrally with the output shaft is arranged between the gear and a gear, and a sleeve that is slidable by fitting with a spline provided on the clutch hub is used. In actual shifting, shifting and power transmission are performed by sliding a sleeve fitted to a spline of a clutch hub and fitting the sleeve to a spline clutch of a low-speed side gear or a high-speed side gear.

As a method of sliding a sleeve with respect to a clutch hub, there is a method in which a shift arm is fitted into a peripheral groove of each sleeve and a shift rod is operated to support or operate the shift arm. Each shift arm and shift rod are fixed by appropriate fixing means such as a bolt, a spring pin, or welding. Therefore, one shift arm and one shift rod are used for shifting between a pair of low-speed and high-speed gears, respectively.
Three shift rods are used in a transmission with five forward steps and one reverse step, and four shift rods are used in a transmission with six forward steps and one reverse step.

FIGS. 1 and 2 show an example of a transmission. FIGS. 1 and 2 show an example of a transmission synchronizing device according to the present invention. The structure of the prerequisite is the same as that of a conventional transmission synchronizing device.
With reference to FIG. 1 and FIG. 2, an outline of a basic structure of a transmission synchronizing device will be described. In the transmission 1, a driving force from an input shaft (not shown) is once transmitted to a counter shaft 2 (FIG. 2) via a gear, and constantly rotates a gear 33 fixed to the counter shaft 2. . On the output shaft 3 parallel to the counter shaft 2, from a large-diameter gear to a small-diameter gear that always meshes with the gear 33 on the counter shaft 2 (only some of the gears 6 and 7 are shown in FIG. 1), respectively. It is rotatably arranged via bearings (only bearings 8 and 9 are shown). An intermediate portion of the output shaft 3 is rotatably supported by a casing 4 made of an aluminum alloy via a bearing 5. The gear 6 is a low-speed gear, and the gear 7 is a high-speed gear. Therefore, when the shift is in a neutral state, all the gears including the gears 6 and 7 supported on the output shaft 3 are idle on the output shaft 3. A synchronizer 10 is provided between the output shaft 3 and the gears 6 and 7. By operating the synchronizer 10 by operating a shift lever (not shown), one of the gears 6 and 7 is connected to the output shaft 3. The reverse gear has a reverse idle gear between the gear on the counter shaft and the gear on the output shaft.

The synchronizer 10 is provided integrally with the clutch hub 11 provided so as to be spline-fitted to the output shaft 3 and to rotate integrally with the output shaft 3, and with the gears 6 and 7 on both sides of the clutch hub 11. And a block in which dog teeth 14 are provided between the dog teeth 13, 13 formed on the outer periphery and the clutch hub 11 and the dog teeth 13 and synchronize the relative rotation between the clutch hub 11 and the dog teeth 13. Ring 1
5, 15 and an annular sleeve 17 which is provided slidably in the axial direction and has spline teeth 18 formed on the inner peripheral surface for engaging with splines 12 formed on the outer peripheral surface of the clutch hub 11. . The engagement surface between the block ring 15 and the dog tooth body 13 is a conical clutch surface 16,
When the block ring 15 shifts in the direction of the dog tooth 13, the block ring 15 and the dog tooth 13 are engaged with the clutch. A peripheral groove 19 into which a shift arm 20 described later is fitted is formed in the outer peripheral portion of the sleeve 17. In the neutral state, as shown in FIG.
Of the spline teeth 18 of the clutch hub 11
2 and do not mesh with the teeth of the block ring 15 and the dog teeth 14. Block ring 15,
15 is movable in the axial direction of the output shaft 3. Dog teeth 1
4, block ring 15 and sleeve 17 constitute a spline clutch in the synchronization device. Output shaft 3
A similar synchronizing device is provided between the output shaft 3 and the other rotatable pair of transmission gears. Since the dog teeth 13 and 13 are provided integrally with the gears 6 and 7, the gears 6 and 7 are dog gears.

For example, in the case of 5 forward speeds, 1 reverse speed, 1st speed and reverse speed, 2nd speed and 3rd speed, 4th speed and 5th speed
A total of three shift rods for speed are supported in fitting holes formed in the casing 4 so as to be displaceable in the axial direction (shift direction) of each shift rod. Each shift rod is provided with a shift arm for shifting. In the case of the example shown in FIG.
Are slidably fitted in fitting holes 31 formed in the casing 4 in the axial direction. The shift arm 20 includes a main body 21 fixed to the shift rod 30 by an appropriate fixing means such as a bolt, and an arm 22 extending from the main body 21 along the outer periphery of the sleeve 17. The sleeve 17 corresponds to the shift arm 20, and a claw 23 provided at the tip of the arm portion 22 of the shift arm 20 is engaged with the circumferential groove 19 of the sleeve 17. When the shift lever is operated, the shift arm 20 is moved together with the shift rod 30.
Is displaced in the axial direction, and the sleeve 17 is
As a result, the gear shifts along the spline fitting portion with the clutch hub 11.

FIG. 2 shows how the lubricating oil is pumped from the lubricating oil reservoir. Lubricating oil is stored in the casing 4 of the transmission 1, and the oil level of the lubricating oil pool is indicated by 32. The lower part of the gear 33 fixed to the counter shaft 2 and having a pitch circle indicated by a two-dot chain line rotates while being immersed in the lubricating oil reservoir. As the gear 33 rotates clockwise in the drawing, the lubricating oil L in the lubricating oil reservoir is repelled as shown by the arrow. A part of the lubricating oil that has been splashed adheres to the circumferential groove 19 of the sleeve 17 that is disposed adjacent to the gear 6 or 7 that meshes with the gear 33 and rotates together with the clutch hub 11, and is further carried upward.

The transmission 1 is configured as described above, and is operated as follows. When the sleeve 17 is shifted in either the left or right axial direction via the shift arm 20 by a shift operation by a shift lever (shift operation lever), the tip of the spline teeth 18 of the sleeve 17 engages with the block ring 15 and Block ring 15
Against the conical clutch surface 16 of the dog tooth 14. As a result, the block ring 15 and the dog tooth body 13 on which the dog teeth 14 are formed engage with the friction clutch, and the rotation of the block ring 15 and the gear 6 or 7 is synchronized.
When the sleeve 17 is further moved in the same direction, the sleeve 1
The 7 spline teeth 18 completely mesh with the teeth of the block ring 15. When the synchronous action of the sleeve 17 and the block ring 15 is obtained, the spline teeth 18 and the dog teeth 14 can be smoothly engaged by further moving the sleeve 17 in the same direction. When the shift of the sleeve 17 is completed, the dog tooth 13 and the sleeve 1 are moved from the gear 6 or 7.
7, a power transmission path leading to the clutch hub 11 and the output shaft 3 is formed.

FIG. 5 is a sectional view showing a fitting portion between a claw portion of a shift arm and a circumferential groove of a sleeve in a conventional transmission synchronizing device. FIG. 6 is a sectional view of a shift arm claw of the synchronizing device shown in FIG. FIG. 8 is an explanatory view showing a state in which lubricating oil attached to the circumferential groove of the sleeve reaches the claw portion of the shift arm at a fitting portion between the portion and the circumferential groove of the sleeve. In a conventional transmission synchronizing device, a shift arm is denoted by reference numeral 40 and described. The claw 43 provided at the tip of the arm portion 42 of the shift arm 40 is fitted in the circumferential groove 19 of the sleeve 17, and the shift arm 40 is operated by operating the shift lever.
The sleeve 17 is operated in the axial direction by shifting in the axial direction. Since the sleeve 17 is integral with the output shaft 3 in the rotation direction, the sleeve 17 rotates with the output shaft 3 at high speed. On the other hand, since the shift arm 40 does not rotate with the sleeve 17, the claw 43 of the shift arm 40 always runs in the circumferential groove 19 of the sleeve 17 when the output shaft 3 is rotating. In order to transmit the movement of the shift arm 40 in the shift direction to the sleeve 17 without play or backlash, the claw 4
The gap in the shift direction is set as small as possible between the groove 3 and the circumferential groove 19. Therefore, the sliding part 4
No. 4 needs to be supplied with lubricating oil at all times.

As described with reference to FIG. 2, the lubricating oil that rotates together with the sleeve 17 collides with one of the claw portions 43 on the leading side where the sleeve 17 rotates around the claw portion 43 due to the rotation. Although the shift arm 40 and the sleeve 17 slide at a high speed with respect to each other,
It is difficult to supply the lubricating oil to the sliding portion 44 and maintain the supplied lubricating oil. That is, the sliding portion 44 between the circumferential groove 19 of the sleeve 17 and the claw portion 43 of the shift arm 40
As described above, the gap formed between the sliding surface 45, which is the side surface of the circumferential groove 19, and the sliding surface 46, which is the side surface of the claw portion 43 of the shift arm 40, is relatively small.
As shown in FIG. 6, since the shape of the tip 47 of the claw 43 of the shift arm 40 is perpendicular to the flow of the lubricating oil, the lubricating oil bounces off after colliding with the tip 47 of the claw 43. , A narrow gap 44 between the sliding surface 45 and the sliding surface 46
a, 44b cannot be supplied with sufficient lubricating oil.
For this reason, the sliding surfaces 45 and 46 may run out of lubricating oil and cause wear and seizure. Further, lubricating oil supplied without rebounding is also applied to the claw portion 43 in the sliding portion 44.
There is a possibility that the supply may be biased to the larger gap (the right gap 44b in FIG. 6) between the groove and the circumferential groove 19.

The sliding structure of the shift arm (shift fork) is used as a sliding structure of the shift arm in order to ensure smooth operation in the sliding groove of the sleeve and to prevent abrasion at the contact surface between the shift arm and the sliding groove. , Jiko 57-41
No. 8 discloses a technique disclosed in Japanese Patent Publication No. According to the sliding structure of the shift arm disclosed in this publication, the shift portion of the shift arm that fits into the sliding groove of the sleeve has a slanted or arcuate shape at the corner facing the rotating direction of the sleeve. A chamfered portion and one or more oil grooves extending from the chamfered portion to the middle of the shift portion are provided.
With the rotation of the sleeve, the lubricating oil adhering to the sliding groove flows into the oil groove from the chamfered part without being scraped off at the shift part, and lubricates the contact surface.

Japanese Patent Publication No. Sho 62-2666 discloses lubrication of a contact surface between a shift arm and a sliding groove of a sleeve. The shift arm disclosed in this publication can supply lubricating oil to a sliding surface of the shift arm from a collecting unit that collects dropped or splashed lubricating oil. The collecting portion for collecting the lubricating oil is constituted by an oil collecting wall slightly extended at the tip of a supporting bone portion wider than the sliding claw portion of the shift arm. The collecting portion may be formed as a U-shaped oil collecting groove provided with walls on both sides of the oil collecting wall, or as an oil collecting tank having an opening at the tip of the supporting bone portion facing the sleeve. In the oil collecting tank, an oil hole for supplying lubricating oil can be formed on the sliding surface.

Japanese Patent Application Laid-Open No. 57-795 discloses a technique for improving the wear resistance of the sliding surface of the shift arm with the sleeve.
No. 34 discloses a technique. In the shift arm disclosed in this publication, a chromium plating film is formed on the claws of the shift arm made of cast iron, and the surface of the film is puff-polished to reduce the surface roughness to 5 μm or less. The surface roughness can be reduced without generating thermal strain on the sliding surface as in induction hardening.

Further, a structure for supplying lubricating oil to the sliding surface between the claw portion of the shift arm and the groove of the sleeve has been proposed.
No. 902. According to the structure disclosed in this publication, lubricating oil is supplied to the sliding surface of the claw portion through a lubrication passage drilled from the tip of the claw portion of the shift arm and a through hole intersecting the lubrication passage. However, it only guides the lubricating oil that has entered the oil supply passage into the through hole, and the lubricating oil that reaches the tip of the claw portion of the other shift arm simply bounces off, as in the conventional structure. So that it is not supplied to the sliding surface. Further, since the through holes extend at right angles to the flow of the lubricating oil, there is no effect of correcting the uneven supply of the lubricating oil. Furthermore, forming such an oil supply hole and a through hole has a problem that the number of steps of machining increases and the manufacturing cost increases.

[0015]

Therefore, when the lubricating oil moving in the groove of the sleeve rotating at high speed collides with the claw of the shift arm, the lubricating oil is not simply rebounded by the claw of the shift arm. And a synchronization device for a transmission that can guide the shift arm claws and the sleeve grooves to be supplied to sliding surfaces that slide with each other with the force of lubricating oil collision. There are issues to be addressed.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and the shape of the claw portion of the shift arm colliding with the lubricating oil is devised so that the claw portion of the shift arm collides with the lubrication oil. The lubricating oil is guided to the sliding surface between the claw of the shift arm and the groove of the sleeve that slides with each other, and the sliding surface is sufficiently lubricated so that the shift arm operates smoothly with respect to the sleeve and is worn. It is an object of the present invention to provide a transmission synchronizing device capable of preventing the transmission.

According to the present invention, there is provided a clutch hub fixed to a rotating shaft, a sleeve slidably fitted to the clutch hub and having a circumferential groove formed therein, and a sleeve for sliding the sleeve relative to the clutch hub. A shift arm having a claw engaging with the peripheral groove of the sleeve at a distal end; lubricating oil is supplied to the distal end of the claw of the shift arm; The present invention relates to a transmission synchronizing device comprising a tapered guide surface for supplying to a sliding portion of a transmission.

The transmission synchronizing device according to the present invention is configured as described above, and operates as follows.
That is, a tapered guide surface for supplying lubricating oil to the sliding surfaces of the claw portion and the circumferential groove of the sleeve is formed at the tip of the claw portion of the shift arm that engages with the circumferential groove of the sleeve. As a result, the tapered guide surface protrudes in the direction opposite to the rotation direction of the sleeve, and the lubricating oil that has collided with the tip of the claw flows along the tapered guide surface due to its momentum and is supplied to the sliding portion. You.

In this transmission synchronizing device, the tapered guide surface intersects at the center of the tip of the claw and is inclined and connected to the sliding surface of the claw forming the sliding portion. It is constituted by a pair of inclined surfaces. The shift arm is shifted in any lateral direction by the operation of the shift operation lever, but the lubricating oil is supplied so as to be evenly distributed to the sliding portions on both sides of the claw portion by the colliding inclined surface.

In the transmission synchronizing device, the shift arm captures the lubricating oil by covering the outside of a space formed between the tapered guide surface of the claw portion and the circumferential groove of the sleeve. It has a capturing part. The lubricating oil that collides with the tip of the claw tends to scatter outward due to the centrifugal force of the sleeve, but the lubricating oil that has entered the space formed between the tapered guide surface and the circumferential groove is , Are effectively supplied to the sliding portion by lubrication of the sliding portion.

Furthermore, in this transmission synchronizing device, a plurality of dog-tooth gears that can mesh with the sleeve are rotatably provided on the rotating shaft so that a combination of gears having different gear ratios can be selected. A block ring is disposed on the dog-toothed gear so as to be able to engage the clutch. The shift arm shifts the sleeve in response to an operation of a shift operation lever. And the sleeve meshes with the dog-tooth gear, so that the rotation speed of the rotation shaft and the dog-tooth gear is synchronized.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a transmission synchronizing device according to the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a part of an embodiment of a transmission synchronizing apparatus according to the present invention, FIG. 2 is a cross-sectional view of a transmission synchronizing apparatus according to the present invention, and FIG. 3 is a transmission synchronizing apparatus shown in FIG. FIG. 4 is an explanatory view showing the flow of lubricating oil around the claw portion of the shift arm of the transmission synchronizing device shown in FIG.

The synchronizing device 1 of the transmission 1 shown in FIGS. 1 and 2
The basic structure of “0” is the same as that already described in the section of the related art, and a duplicate description will be omitted. The shift arm 20 includes a main body portion 21 and an arm portion 22 extending along the outer periphery of the sleeve 17.
A claw portion 23 is formed on the inside of the distal end portion of. Claw part 23
Are slidably fitted in the circumferential groove 19 of the sleeve 17. The pair of arm portions 22 of the shift arm 20, that is, the arm portion 22 (L) on the leading side and the arm portion 22 (T) on the trailing side are manufactured symmetrically to enhance versatility as parts. However, the arm portion 22 important from the viewpoint of supplying the lubricating oil to the sliding portion 24 is the arm portion 22 (L) on which the sleeve 17 shown on the right side of FIG. .

The tip of the claw 23 is formed on a tapered guide surface 27. That is, the inclined surfaces 28, 28 taper toward the tip from the sliding surfaces 26 on both sides in the width direction of the claw 23.
Are formed. The direction in which the arm portion 22 extends and the direction in which the sleeve 17 rotates are opposite to each other.
The inclined surfaces 28, 28 intersect at a ridgeline 29 which is the forefront. Since the shift arm 20 is shifted in any shift direction, it is preferable that the ridgeline 29 is positioned at the center of the width of the claw portion 23 and the tapered guide surface 27 is formed symmetrically.

In the synchronizing device 10 having the pawl FIG. 23 constructed as described above, as shown in FIG. 2, a part of the lubricating oil L repelled by the gear 33 is
The claw 2 of the shift arm 20
3 collides with the tapered guide surface 27. FIG.
As shown in FIG.
Flows along the direction of inclination of the inclined surfaces 28, 28 as shown by the arrows, flows into gaps 24a, 24b formed between the sleeve 17 and the claw portion 23, and lubricates the sliding portion 24.
As a result, the sliding surface 25 of the circumferential groove 19 and the sliding surface 26 of the claw portion 23 are lubricated, and the occurrence of seizure or wear is prevented. As in the case of the claw portion 43 of the conventional shift arm 40 having an end surface perpendicular to the rotation direction T of the sleeve 17, the momentum of the lubricating oil completely stops at the time of collision, and Does not flow into the gaps 24a and 24b formed in the first position.

The shift arm 20 is formed by a space formed between the tapered guide surface 27 of the claw portion 23 and the peripheral groove 19 of the sleeve 17 at the tip end of the arm portion 22, that is, an inclined surface 28. It has a capturing portion 22a that covers the outside of the wedge-shaped space. The catching portion 22a functions to catch the lubricating oil L that has collided with the tapered guide surface 27 and to prevent the lubricating oil L from scattering to the outside due to its centrifugal force.
The captured lubricating oil L is sequentially supplied to gaps 24a and 24b formed between the sliding surfaces 25 and 26 to lubricate the sliding portion 24.

One or a plurality of guide grooves 35 extending to the sliding surface 26 connected to each of the inclined surfaces 28, 28 are provided.
Can be formed. The lubricating oil L flowing along the inclined surface 28 has a tendency to be more reliably guided toward the sliding portion 24 by the guide groove 35. In the above embodiment, the tapered guide surface 27 is constituted by the inclined surface 28 as a flat surface. However, the present invention is not limited to this. If the tapered guide surface 27 has a guide function in supplying lubricating oil, it is formed into a curved surface. Obviously it is good. 1 to 4
In the synchronizer 10 of the transmission 1 shown in FIG. 1, the tapered guide surface 27 of the shift arm 20 is
9 is formed at a right angle to the bottom surface, but the tapered guide surface formed at the tip of the claw portion 23 of the shift arm 20 is
The inclined surfaces 28, 28 may be formed so as to be inclined with respect to the bottom surface of the peripheral groove 19, such that the portion of the ridge line 29 closer to the bottom of the peripheral groove 19 of the sleeve 17 approaches the main body portion 21 of the shift arm 20. . When the tapered guide surface 27 is formed in this manner, the lubricating oil which is carried along with the rotation of the sleeve 17 and collides with the tapered guide surface, together with the force approaching to both sides in the width direction of the claw portion 23, is provided at the bottom of the circumferential groove 19. A force acting in the direction occurs. The centrifugal force acting on the lubricating oil can be offset by the force acting in the direction of the bottom of the circumferential groove 19, and the sliding surface 2
Sufficient lubricating oil L can be fed into the region near the bottom of peripheral groove 19 among 5, 26. Further, since the tapered guide surfaces 27 are formed on the claw portions 23 of both the arm portions 22, the claw portions 23 of the shift arm 20 are moved by the guiding action of the tapered guide surfaces 27 in assembling the transmission 1. It becomes easy to fit in the circumferential groove 19.

[0028]

As described above, the transmission synchronizing device according to the present invention has a tapered guide surface for supplying lubricating oil to the tip of the claw portion of the shift arm to the sliding portion between the claw portion and the circumferential groove of the sleeve. When the lubricating oil carried in the groove of the sleeve rotating at high speed collides with the claw of the shift arm, the lubricating oil is guided by the tapered guide surface with the force of the collision, and the lubricating oil is Sufficiently lubricate the sliding surface. Therefore, the shift arm slides smoothly with respect to the sleeve, and the sleeve can be smoothly moved in the shift direction even when the shift arm is operated. As a result, seizure and abrasion caused by running out of lubricating oil on the sliding surface of the sleeve circumferential groove and the sliding surface of the shift arm claw portion can be prevented, and the durability of the transmission synchronizing device can be improved. In addition, the service life can be extended.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a transmission synchronizing device according to the present invention.

FIG. 2 is a diagram illustrating supply of lubricating oil to a transmission synchronization device according to the present invention.

FIG. 3 is an enlarged perspective view showing a part of the transmission synchronization device shown in FIG. 1;

FIG. 4 is an explanatory diagram showing a flow of lubricating oil by a claw portion of a shift arm of the transmission synchronizing device shown in FIG. 1;

FIG. 5 is a cross-sectional view of a fitting portion between a shift arm and a sleeve of a conventional transmission synchronizing device.

6 is an explanatory diagram showing a flow of lubricating oil by a claw portion of a shift arm of the transmission synchronizing device shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission 3 Output shaft 4 Casing 6, 7 Dog toothed gear 10 Synchronizer 11 Clutch hub 13 Dog tooth 14 Dog tooth 15 Block ring 16 Conical clutch 17 Sleeve 19 Circumferential groove 20 Shift arm 21 Main body part 22 Arm part 22a Capture Part 23 claw part 24 sliding part 25, 26 sliding surface 27 tapered guide surface 28 inclined surface 29 ridgeline 30 shift rod

Claims (4)

[Claims] 1. A clutch hub fixed to a rotating shaft, a sleeve slidably fitted to the clutch hub and having a circumferential groove formed therein, and a tip portion for sliding the sleeve relative to the clutch hub. A shift arm having a claw engaging with the circumferential groove of the sleeve, and lubricating oil is applied to a tip of the claw of the shift arm between the claw and the circumferential groove of the sleeve. A synchronizing device for a transmission, comprising a tapered guide surface for supplying a moving portion. 2. The tapered guide surface is a pair of inclined surfaces that intersect at the center of the tip end of the claw portion and are inclined and connected to the sliding surface of the claw portion forming the sliding portion. The transmission synchronizing device according to claim 1, comprising: 3. The shift arm has a catching portion that catches the lubricating oil by covering an outside of a space formed between the tapered guide surface of the claw portion and the circumferential groove of the sleeve. 3. The transmission synchronizing device according to claim 1, comprising: 4. A plurality of dog-tooth gears that can mesh with the sleeve are rotatably provided on the rotating shaft so that a combination of gears having different speed ratios can be selected. Is arranged so that a block ring can be engaged with the clutch, the shift arm shifts the sleeve in response to an operation of a shift operation lever, the block ring is engaged with the dog gear, and the block ring is engaged with the gear. The transmission synchronizing device according to any one of claims 1 to 3, wherein a sleeve meshes with the dog-tooth gear to synchronize the rotation speeds of the rotation shaft and the dog-tooth gear.