JP2582080B2 - Vehicle transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a transmission for a vehicle, and more particularly, to a rotary transmission in which a shift is sequentially performed in conjunction with rotation of a shift drum.

(Prior Art) The present applicant has already filed an application for a rotary transmission for a vehicle in Japanese Patent Application Laid-Open No. 57-138484.

In such prior application, the transmission is provided with a main shaft provided with a transmission gear to which engine power is input, a counter shaft provided with a transmission gear meshing with the transmission gear, and the transmission gear being rotated. Switch, and
Rotation in one direction sequentially shifts to a high-speed shift position, and when further rotated from the highest-speed shift position, returns to the lowest-speed shift position, and at least frictionally engages a member that rotates in a shift state with the highest-speed shift position. With the friction spring biased by the friction spring and engaged with the shift drum to prevent the shift drum from rotating from the highest speed shift position to the lowest speed shift position, and that the bias of the friction spring is released And a lock arm that swings by its own weight to release engagement with the shift drum.

According to such an earlier application, shifting from the highest speed to the lowest speed while power is being transmitted between the engine and the drive wheels is prevented.

(Problems to be Solved by the Invention) However, in the prior application, the lock arm is pivotally mounted on the countershaft, and therefore, the lock arm and the shift arm correspond to the distance between the countershaft and the shift drum. It has to be long, the lock arm is large,
In addition, there is a problem that various restrictions are imposed by the enlarged lock arm when arranging components of another transmission.

The present invention relates to the improvement of the above-mentioned application, and an object of the present invention is to provide a transmission for a vehicle which can reduce the size of a lock arm and is advantageous in disposing other components of a transmission. To be.

(Means for Solving the Problems) In order to achieve the above object, according to the configuration of the present invention, a shift drum 17 is provided at a position separated from the main shaft 11 and the counter shaft 13, and the shift drum 17 and the main shaft 11 Alternatively, the lock arm 25 is provided between the counter shafts 13, and the friction spring 61 is provided on the main shaft 11 or the counter shaft 13.

(Operation) As in the conventional case, it is not necessary to lengthen the lock arm 25 corresponding to the center distance between the shift drum 17 and the counter shaft 13, so that the lock arm 25 can be reduced in size, and other components of the transmission can be realized. This is advantageous in disposing the.

(Embodiment) Hereinafter, a case where an embodiment of the present invention is applied to a transmission for a motorcycle will be described.

FIG. 1 is a sectional view of a transmission chamber and a crankcase.
FIG. 2 is a developed view of the main shaft and the counter shaft, FIG. 3 is a developed view of the main shaft and the shift drum, and FIG. 4 is a view taken along the arrow IV in FIG.

Reference numeral 1 denotes a crankcase. The crankcase 1 includes left and right halves 1A and 1B. A crankcase 3 is formed at the front of the crankcase 1, and a transmission chamber 5 is formed behind the crankcase 3.

A crankshaft 7 is disposed in the crank chamber 3, and a transmission 9 is disposed in the transmission chamber 5.

The transmission 9 includes a main shaft 11 provided at the front of the transmission chamber 5, a counter shaft 13 provided behind the main shaft 11, a main shaft 11, a transmission gear 15 provided on the counter shaft 13, Shift drum 17 and counter shaft 13 disposed below shaft 11
A shift fork shaft 19, shift forks 21, 23, a lock arm 25, and the like, which are disposed between the shift drum 17 and the shift drum 17.

The power of the crankshaft 7 is input to the main shaft 11 via the clutch 27.

The transmission gear 15 provided on the main shaft 11 includes a first gear 29A formed integrally with the main shaft 11, and second and fourth gears 29 rotatably disposed on the main shaft 11.
B, 29D and a third spline engaged with the main shaft 11
It consists of gear 29C.

The third gear 29C is movable in the axial direction, and is engaged with the second gear 29B or the fourth gear 29D by the dog clutches 31 and 33 to rotate the second and fourth gears 29B and 29D integrally with the main shaft 11.

The transmission gear 15 provided on the counter shaft 13 includes first and third gears 35A and 35C rotatably disposed on the counter shaft 13, and second and fourth gears 35B and 35B spline-engaged with the counter shaft 13. 35D, the first to fourth gears 3
.. Can be freely engaged with the first to fourth gears 29.

The fourth gear 35D is movable in the axial direction, is engaged with the first gear 35A or the third gear 35C by the dog clutches 37 and 39, and
The third gears 35A and 35C are rotated integrally with the counter shaft 13.

The axial movement of the third gear 29C and the fourth gear 35D is caused by the axial movement of the first and second shift forks 21 and 23 whose intermediate portion is fitted to the shift fork shaft 19 and one end of which engages with the shift drum 17. The first and second shift forks 21 and 23 are axially moved by the rotation of the shift drum 17.

A drive sprocket 41 that transmits the engine power, which has been appropriately shifted in speed ratio, to the rear wheels is attached to a portion of the counter shaft 13 protruding from the transmission chamber 5.

A star-shaped cam 43 is attached to a portion of the shift drum 17 protruding from the transmission chamber 5, and a plurality of pins 45 project from the cam 43 at intervals in the circumferential direction.

Reference numeral 47 denotes a shift arm. The shift arm 47 swings in conjunction with a change pedal, and engages the claw body 49 at the tip with the pin 45 to rotate the shift drum 17. Reference numeral 51 denotes a cam stopper which engages with the cam 43 and urges the shift drum 17 to each shift position.

When the change pedal is depressed, the shift drum 17 rotates in the counterclockwise direction in FIG. 1, and when the change pedal is kicked up, the shift drum 17 is rotated in the clockwise direction.
17 rotates 72 degrees each.

FIG. 2 shows the neutral position. When the change pedal is depressed from this state, the shift drum 17 rotates counterclockwise, and the fourth gear 35D is engaged with the first gear 35A by the second shift fork 23. , The first speed (lowest speed).

In the 2nd speed, by further depressing the change pedal,
The fourth gear 35D is returned to the original state, and the third gear 29C is engaged with the second gear 29B by the first shift fork 21.

The 3rd speed, by further depressing the change pedal,
It is obtained by returning the third gear 29C to the original state and engaging the fourth gear 35D with the third gear 35C.

In the fourth speed (highest speed), the fourth gear 35D is returned to its original state by further depressing the change pedal, and the third gear 29C is moved to the fourth gear.
Obtained by engaging with gear 29D. If the change pedal is further depressed from this state, it returns to the original neutral position.

The lock arm 25 is provided with the intermediate portion pivotally mounted on the shift fork shaft 13, and 53 in the figure indicates a stop ring.

At one end of the lock arm 25, a claw 57 that can be engaged with the notch 55 of the shift drum 17 is formed, and at the other end, a weight 59 that separates the claw 57 from the notch 55 is formed.

The lock arm 25 is driven by the friction spring 61
At least in the fourth speed shift state, the shift drum 17
Urges in the direction of engagement with the notch 55 of

In the embodiment, the friction spring 61 is frictionally engaged with the boss 62 of the second gear 29B.
Of the counter shaft
A resilient force is applied to the lock arm 25 when the 13 rotates.

When the shift drum 17 rotates counterclockwise in a state where the lock arm 25 is biased by the friction spring 61, the claw 57 engages with the notch 55 to shift the shift drum 17.
The rotation of the shift drum 17 is prevented, and the shift drum 17 is maintained at the fourth speed shift position. This prevents the shift from the fourth speed to the first speed.

In addition, when the shift drum 17 rotates clockwise, the claw 57 is disengaged from the notch 55 due to the groove surface 55A of the notch 55, and the clockwise rotation is allowed.

Further, when power is not transmitted between the engine and the drive wheels, for example, at the time of stoppage, the elastic force of the friction spring 61 does not act on the lock arm 25 because the counter shaft 13 is not rotating, and Lock arm by part 59
25 swings, the claw 57 is separated from the cutout 55, and the clockwise and counterclockwise rotation of the shift drum 17 is allowed.

Since the present embodiment is configured as described above, it is not necessary to lengthen the lock arm 25 in accordance with the center distance between the shift drum 17 and the counter shaft 13 as in the related art, and the lock arm 25 can be downsized.

Further, since the size of the lock arm 25 can be reduced, it is advantageous in arranging other transmission components.

In addition, in the embodiment, since the shift fork shaft 19 is used, the lock arm can be used without increasing the number of parts.
25 can be arranged.

The friction spring 61 is connected to the counter shaft 13
The gear may be disposed on a member that rotates in a shift state at least at the highest-speed shift position, such as another gear, a gear on the counter shaft 13 or a gear on the main shaft 11.

Further, the lock arm 25 may be attached to a pin or the like protruding from the side wall of the mission chamber 5.

(Effects of the Invention) As is apparent from the above description, according to the present invention, it is possible to reduce the size of the lock arm and to obtain a transmission for a vehicle which is advantageous in disposing other transmission components. Can be.

[Brief description of the drawings]

1 is a sectional view of a transmission chamber and a crankcase, FIG. 2 is a development of a main shaft and a counter shaft, FIG. 3 is a development of a main shaft and a shift drum, and FIG. FIG. In the figure, 1 is a crankcase, 7 is a crankshaft, 9 is a transmission, 11 is a main shaft, 13 is a counter shaft, 17
Is a shift drum, 19 is a shift fork shaft, 25 is a lock plate, and 61 is a friction spring.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-12163 (JP, A) JP-A-57-138484 (JP, A) JP-A-60-127156 (JP, U)

Claims (1)

(57) [Claims] 1. A main shaft to which a power is input and provided with a transmission gear; and a counter shaft provided with a transmission gear meshing with the transmission gear; The shift drum sequentially shifts to a high-speed shift position, and returns to the lowest-speed shift position when further rotated from the highest-speed shift position. Friction frictionally engaged with a member rotating in a shift state by the highest-speed shift position The spring is biased by the friction spring and engages with the shift drum to prevent the shift drum from rotating from the highest speed shift position to the lowest speed shift position, and by its own weight in a state where the friction spring is released. And a lock arm that swings to disengage from the shift drum. The shift drum is disposed at a position separated from the shaft and the counter shaft, the lock arm is disposed between the shift drum and the main shaft or the counter shaft, and the friction spring is disposed on the main shaft or the counter shaft. A transmission for a vehicle, comprising: