JPH10339369A - Transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission for a vehicle enabled to suppress an engine height also narrow an engine width. SOLUTION: In a transmission for a vehicle, a speed change gear 13 is provided on one shaft, a speed change gear 12 is provided on the other shaft, by rotating a shift drum 20, a pair of shift forks 16, 17 provided in one shaft and a single shift fork 14 provided in the other shaft are operated, meshing between the speed change gear 13 on one shaft and the speed change gear 12 on the other shaft is changed, and a speed change is performed. In this case, in both sides of a line connecting the axial center of one shaft and an axial center of the shift drum 20, a first/second guide bar 19, 18 supporting a pair of the shift forks is arranged to be sorted, each guide bar 19, 18, 15 including a third guide bar 15 supporting the single shift fork 14 in the other shaft is arranged, as viewed from the axial center of the shift drum 20, in its peripheral direction, by the order of the first/second/third guide bar 19, 18, 15, and a distance between shafts of the first/second guide bars 19, 18 is formed large than a distance between shafts of the second/third guide bars 18, 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular transmission.

[0002]

2. Description of the Related Art For example, a motorcycle or the like is provided with a transmission, and as shown in FIGS.
And a drive shaft 101, a transmission gear 102 is provided on the main shaft 100 and a transmission gear 103 is provided on the drive shaft 101, and a shift fork 105 on the main shaft side and a shift fork on the drive shaft side are provided by rotation of the shift drum 104. By operating the gears 106 and 107, the transmission gear 102 on the main shaft 100 and the transmission gear 10 on the drive shaft 101
In some cases, the transmission is changed by changing the engagement with the third gear.

[0003]

As described above, the shift gears 102 on the main shaft 100 and the shift gears 103 on the drive shaft 101 are operated by operating the shift forks 105-107.
In the case of shifting gears by changing the engagement with the main shaft 100 and the drive shaft, the guide bars 108 to 110 supporting the respective shift forks 105 to 107 are concentrated around the shift drum 104. The distance between the shafts of the shift drum 101 and the shift drum 104 increases, and the position of the shift drum 104 decreases accordingly, and the engine height increases. Also, since there is a possibility that the shift forks 105 to 107 may interfere with each other, the shift fork 105
To 107 are difficult to arrange in the axial direction of the guide bars 108 to 110, and there are problems such as an increase in the engine width.

The present invention has been made in view of the above circumstances, and has as its object to provide a vehicular transmission capable of reducing the engine height and narrowing the engine width.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve the object, the invention according to claim 1 is directed to a method in which a transmission gear is provided on one shaft and a transmission gear is provided on the other shaft. A shift gear on one shaft and a shift on the other shaft by operating a pair of shift forks provided on one shaft and a single shift fork provided on the other shaft by rotation of the shift drum. In a vehicular transmission that changes gearing by engaging with a gear, a first and a second fork supporting the pair of shift forks are provided on both sides of a line connecting the axis of the one shaft and the axis of the shift drum. The two guide bars are distributed and arranged, and the arrangement of the respective guide bars including the third guide bar for supporting the single shift fork of the other shaft is arranged on the shift drum as viewed from the axis of the shift drum. Circumferentially, The first guide bar, the second guide bar, and the third guide bar are arranged in this order, and the center distance between the first guide bar and the second guide bar is determined by the center distance between the second guide bar and the third guide bar. A transmission for a vehicle, which is enlarged. ], The distance between the shaft on which the transmission gear is arranged and the shift drum is reduced, and the height of the engine can be reduced accordingly. Further, by distributing and arranging the first and second guide bars without concentration, the shift forks can be prevented from interfering with each other, and the shift forks can be disposed close to the guide bar in the axial direction. Can be reduced.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a vehicle transmission according to an embodiment of the present invention; First, a description will be given of an embodiment in which the crankcase shown in FIGS. 1 is a sectional view of the engine, FIG. 2 is a sectional view of the transmission, FIG. 3 is a sectional view taken along the line III-III of FIG. 2, and FIG. 4 is a sectional view taken along the line IV-IV of FIG.

The engine 1 of this embodiment is a four-stroke engine, and uses left and right crankcases 2 and 3. A cylinder body 4 is mounted on the left and right crankcases 2 and 3, and a cylinder head 5 is mounted on the cylinder body 4. A piston 6 is provided on the cylinder body 4 so as to be able to reciprocate, and the piston 6 is connected to a crankshaft 8 via a connecting rod 7. The crankshaft 8 is rotatably supported by left and right crankcases 2 and 3, and the power of the engine 1 is transmitted from the crankshaft 8 to a transmission 9 via a gear train (not shown).

The transmission 9 has a main shaft 10 and a drive shaft 11. A transmission gear 12 is provided on the main shaft 10, and a transmission gear 13 is provided on the drive shaft 11. The transmission gear 12 of the main shaft 10 is
4, the dock clutch 70 is disengaged by this operation, and rotates or idles integrally with the main shaft 10. The shift fork 14 is supported movably in the axial direction integrally with the third guide bar 15.

The transmission gear 13 of the drive shaft 11 is operated in the direction of the drive shaft 11 by a pair of shift forks 16 and 17, and this operation causes the dock clutches 71 and 72 to operate.
And rotates or idles integrally with the drive shaft 11 in the same manner as described above. This pair of shift forks 16, 1
7 is supported so as to be movable integrally with the second and first guide bars 18 and 19, respectively.

Each shift fork 14, 16, 1
The projections 14a, 16a, 17a of the shift drum 20
Are engaged with the cam grooves 20a, 20b, 20c of the shift fork 14, 16, 16,
The gear 17 moves in the direction of the guide shaft, and changes the engagement between the transmission gear 12 on the main shaft 10 and the transmission gear 13 on the drive shaft 11 to change the speed. 3rd, 2nd, 1st of each
The shift bar 1 is provided on the guide bars 15, 18, and 19.
4, 16 and 17 are locked by lock pins 21 to 23, and lock pins 21 to 23 are further split pins 24 to 2.
At 6, the retaining and the axial movement are prevented.

Also, the third, second, and first guide bars 15,
Both ends of 18, 19 are slidably supported by left and right crankcases 2, 3, and the third, second, and first guide bars 15, 18, 19 are hollow. The left crankcase 2 is located outside the vehicle, so that the boss 2
The bottomed holes 30 to 32 are formed in a to 2c, and the end portions 15a, 18a of the third, second, and first guide bars 15, 18, 19 are formed.
19a is slidably supported, but the right crankcase 3 has through holes 33 to 35 formed in the boss portions 3a to 3c so that the third, second, and first guide bars 15, 18, and 19 End portions 15b, 18b, and 19b are slidably supported, the bearing portion does not become an airtight chamber, and the third, second, and first guide bars 15, 18, and 19 have smoothness without resistance due to air pressure. The shift feeling can be improved.

The shift forks 14, 16, 17
And the third, second, and first guide bars 15, 18, and 19 move integrally, so that the support span becomes longer, and the shift forks 14, 16, 17, and the third, second, and first guide bars The stick of 15, 18, 19, that is, twisting is eliminated, and the movement of the shift forks 14, 16, 17 becomes smooth, so that shift failure and shift load can be reduced.

One end 20d of the shift drum 20 is rotatably supported by a support 40 provided on the left crankcase 3, and the other end 20e is rotated by the right crankcase 3 via a bearing 41. Supported as possible. At the other end 20e of the shift drum 20, a support 42 is
The connector 44 is engaged with the internal teeth of the support 42 so as to be integrally rotatable. The connection body 44 is engaged with a retaining plate 50, and the retaining plate 50 is fixed to the right crankcase 3 by bolts 51. The end portion 46a of the shift lever 46 is engaged with the pin portion 45 of the connecting body 44, the base portion of the shift lever 46 is fixed to the end portion of the change shaft 47, and the change shaft 47 is operated by the change lever 48, A return spring 49 is provided at the end of the arm and is always biased in the initial position direction.

On both sides of a line L connecting the axis O1 of the drive shaft 11 and the axis O2 of the shift drum 20, second and first guide bars 1 supporting a pair of shift forks 16 and 17 are provided.
8 and 19 are distributed, and each of the first, second and third guide bars 1 including a third guide bar 15 for supporting a single shift fork 14 of the main shaft 10 which is the other shaft.
The first guide bar 1 is arranged in the circumferential direction of the shift drum 20 as viewed from the axis of the shift drum 20.
9, the second guide bar 18 and the third guide bar 15 in this order, and the axial distance D1 between the first guide bar 19 and the second guide bar 18 is determined by the second guide bar 18 and the third guide bar 15.
Is larger than the distance D2 between the shafts.

As described above, the center distance D3 between the drive shaft 11 on which the transmission gear 13 is disposed and the shift drum 20 is reduced, and the height of the engine can be reduced accordingly. In addition, by distributing and distributing the third, second, and first guide bars 15, 18, and 19 without concentrating, the interference between the shift forks 14, 16, and 17 is eliminated, and the shift forks 4, 16, and 17 are moved to the second position. 3, second, first guide bar 1
5, 18 and 19 can be arranged close to each other in the axial direction, and the engine width can be reduced accordingly.

Next, an embodiment in which the crankcase shown in FIGS. 5 and 6 is split vertically will be described. FIG. 5 is a sectional view of the transmission, and FIG. 6 is a plan view of the vehicle transmission with the upper crankcase removed.

In this embodiment, the same components as those in the embodiment of FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, the upper and lower crankcases 6 are divided.
The main shaft 10 and the drive shaft 11 are supported on the joint surfaces 0 and 61. The shift drum 20 is rotatably provided in the lower crankcase 60. Bosses 60a and 60b are formed inside the lower crankcase 60, and the shift drum 20 is attached to the bosses 60a and 60b.
Are supported at both ends. Note that bosses 60a and 60b may be provided inside the upper crankcase 61 so that both ends of the shift drum 20 may be supported by the shaft.

Bosses 60c to 60e are formed inside one of the lower crankcases 60, and bosses 60f and 60g are formed inside the other. Boss 60c,
The third and second guide bars 1 between the 60d and the boss 60f
5 and 18 are inserted through through holes (not shown) formed in the side wall of the lower crankcase 60, further penetrate through the shift forks 14, 16, and lock pins 21 from the joint surface side with the upper crankcase 61. , 22 and are prevented from coming off by split pins 24, 25, and are slidably supported in the axial direction.

A first guide bar 19 is inserted between a boss 60e and a boss 60g from a through hole (not shown) formed in the side wall of the lower crankcase 60 in the same manner as described above. , Fixed from the side of the joint surface with the upper crankcase 61 with the lock pin 23, further secured with the split pin 26, and supported so as to be slidable in the axial direction. The bosses 60c to 60e are provided with guide bars 15, 18, 19
Are formed short in the axial direction to insert the

The rigidity of the lower crankcase 60 can be improved by the bosses 60c to 60e and the bosses 60f and 60g formed inside. Further, shift forks 14, 16, 17 are prevented from rotating around the third, second, and first guide bars 15, 18, 19 by lock pins 21 to 23, and the lock pins 21 to 23 are further split pins 24. 26, these can be easily assembled from above the lower crankcase 60, and workability is improved. The split pins 24-2
6, the lock pins 21 to 23 may be replaced with screws.

[0021]

As described above, according to the first aspect of the present invention, the distance between the shaft on which the transmission gear is arranged and the shift drum is reduced, and the engine height can be reduced accordingly. In addition, by distributing and arranging the guide bars without concentrating, there is no interference between the shift forks, and the shift forks can be arranged close to the guide bar in the axial direction, and the engine width can be reduced accordingly. It is possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of an engine.

FIG. 2 is a sectional view of a transmission.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

FIG. 5 is a sectional view of a transmission.

FIG. 6 is a plan view of the vehicle transmission with the upper crankcase removed.

FIG. 7 is a sectional view of a conventional engine.

FIG. 8 is a sectional view of a conventional transmission.

[Explanation of symbols]

 Reference Signs List 10 Main shaft 11 Drive shaft 12, 13 Transmission gear 14, 16, 17 Shift fork 15, 18, 19 Third, second, first guide bar 20 Shift drum

Claims (1)

[Claims] A transmission gear is provided on one shaft and a transmission gear is provided on the other shaft. A pair of shift forks provided on one shaft by rotation of a shift drum and a single shift fork provided on the other shaft are provided. In a vehicular transmission, the shift fork is actuated to change the engagement between the transmission gear on one shaft and the transmission gear on the other shaft to change the speed. A first and a second supporting the pair of shift forks on both sides of the line connecting the
The arrangement of the guide bars, including the third guide bar supporting the single shift fork of the other shaft, is arranged around the shift drum as viewed from the axis of the shift drum. In the direction, the first guide bar,
In the order of the second guide bar and the third guide bar, the center distance between the first guide bar and the second guide bar is larger than the center distance between the second guide bar and the third guide bar. Characteristic vehicle transmission.