JPS6314220B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a shift operation mechanism for a transmission.

In the shift operation mechanism, depending on the arrangement of each shift gear train in the transmission, each shift is performed by moving the shift fork in the opposite direction to the operating direction of the fork shaft, which is attached to the casing so as to be movable in the axial direction. May complete the gear train.

The present invention aims to provide a simple speed change operation mechanism that can satisfy the above requirements, and embodiments thereof will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention, in which a casing 1 is
A forkshaft 11 is attached to the fork shaft 11 so as to be movable in the axial direction. The fork shaft 11 is moved in the axial direction by the operator's gear change operation, and a shift head 12 is integrally assembled with a spring pin 13, and a shift fork 14 is assembled so as to be slidable in the axial direction. There is.
The shift head 12 and the shift fork 14 are connected via a pair of arms 15, 16, and both arms 15, 16 are rotatably connected to each other via a connecting pin 17 at one end 15a, 16a. The shaft portion 12a of the shift head 12 and the shaft portion 1 of the shift fork 14 at each other end 15b, 16b.
4a, and are rotatably connected to each other. The connecting pin 17 is movably fitted into the guide hole S ₁ of the bracket 18 fixed to the casing 10 by a bolt ₁₉ at its intermediate portion.
Move under the guidance of. The guide hole _S1 has a circular arc portion A1 centered on the center O of the shaft portion 14a of the shift fork 14 at the illustrated position, and a circular arc portion _A1 centered on the center O of the shaft portion 14a of the shift fork 14,
The connecting pin 17 is located at the intersection of the arcuate portion _A1 and _the straight portion _B1 in the illustrated state. Note that the reference numeral C in the figure indicates a snap spring for preventing slipping off.

In the shift operation mechanism configured in this way,
When the forkshaft 11 is moved a predetermined amount in the axial direction from the illustrated position to the right by the operator's speed change operation, the connecting pin 17 is pulled by the arm 15 and moves to the lower end of the linear portion B ₁ of the guide hole S ₁ as illustrated. move,
At the same time, the shift fork 14 is pushed by the arm 16, slides on the fork shaft 11, and moves a predetermined amount to the left in the figure. Further, when the forkshaft 11 is moved by a predetermined amount in the axial direction from the illustrated position to the left by the operator's speed change operation, the connecting pin 17 is pushed by the arm 15 and the arc-shaped portion A ₁ of the guide hole S ₁
Move to the left end of the diagram. At this time, the arm 16 rotates counterclockwise around the shaft portion 14a of the shift fork 14, so the shift fork 14 is held at the illustrated position (stopped state) while sliding on the fork shaft 11. Ru.

In the above-mentioned embodiment, the guide hole S ₁ is composed of an arcuate portion A ₁ and a straight portion B ₁ .
is adopted, and when the fork shaft 11 moves to the right, the shift fork 14 is moved to the right,
An example has been described in which the shift fork 14 is held at the position shown when the fork shaft 11 moves to the left, but when implementing the present invention, the straight portion B ₂ shown in FIG. A guide hole S ₂ consisting of an arcuate portion A ₂ centered on the center O is adopted to hold the shift fork 14 at the position shown when the forkshaft 11 moves to the right, and to hold the shift fork 14 at the position shown when the forkshaft 11 moves to the left. When moving, the shift fork should be moved to the right, and the guide hole shown in Figure 4 should be used as a guide hole.
Adopting a guide hole _S3 consisting of only a straight part,
It is possible to move the shift fork 14 to the left when the forkshaft 11 moves to the right, and to move the shift fork 14 to the right when the forkshaft moves to the left. Further, when carrying out the present invention, both arms 15, 1
By changing the lengths of the shift fork 14 and the shape and arrangement of the guide holes (or the assembly position of the shift head 12 with respect to the fork shaft 11), the amount of movement of the shift fork 14 relative to the amount of movement of the fork shaft 11 can be set appropriately. Can be done.

In summary, in the present invention, the shift head is integrally assembled to the fork shaft which is assembled to the casing so as to be movable in the axial direction, and the shift fork is attached so as to be slidable in the axial direction. The other ends of a pair of arms are rotatably connected to each other via a connecting pin at one end, and
Further, the connecting pin is engaged with a guide hole provided in a bracket fixed to the casing, so that when the forkshaft moves in one direction, the connecting pin moves while being guided by the guide hole, and the shift fork moves. It is characterized in that it slides on the forkshaft and moves in the other direction.

This not only satisfies the requirements listed in the heading, but also (a) effectively utilizes the essential components of the transmission's shift operation mechanism, namely the forkshaft, shift head, and shift fork; Since it includes three additional elements: an arm, a connecting pin, and a bracket provided with a guide hole, it can be implemented compactly and at low cost. (b) By appropriately changing the length of the arm and the shape of the guide hole, the amount of movement of the shift fork relative to the amount of movement of the forkshaft can be easily and appropriately set. (c) By appropriately setting the shape of the guide hole, when the forkshaft moves in one direction, the shift fork can be moved in the opposite direction to the operating direction of the forkshaft to complete the gear train. When the forkshaft is moved in the other direction, the shift fork is held stationary on the forkshaft, or when the forkshaft is moved in one direction, the shift fork is moved in the opposite direction to the operating direction of the forkshaft. After moving the shift fork to complete one gear train, when moving the forkshaft in the other direction, move the shift fork in the opposite direction to the operating direction of the forkshaft to complete the other gear train. can be done. (d) As mentioned above
With (b) and (c), the shift operation mechanism can be implemented in a wide range of various transmissions. (e) The shift fork moves by being pushed or pulled by the other end of the arm that is rotatably connected to it, and the point at which the force is transmitted from the arm is always constant and does not change. By setting the connection point between the shift fork and the arm at an optimal position, the shift fork can move smoothly on the fork shaft without the risk of unnecessary tilting. (f) A configuration is adopted in which the connecting pin is guided by a guide hole provided in the bracket, and by replacing only the bracket with a different guide hole shape, different shift operation modes as shown in the above embodiments can be achieved. By using common parts such as the casing, fork shaft, shift head, shift fork, pair of arms, and connecting pins, the speed change operation mechanism can be made inexpensive. You can also expect similar effects and effects.

[Brief explanation of the drawing]

Figure 1 is a front view showing one embodiment of the present invention, Figure 2 is a front view showing one embodiment of the present invention;
The figure is a bottom view of the same, FIG. 3 is a front view showing a modification, and FIG. 4 is a front view showing a modification. Explanation of symbols, 10...Casing, 11...Forkshaft, 12...Shift head, 14...
...Shift fork, 15, 16...Arm, 17
...Connecting pin, 18...Bracket, S ₁ , S ₂ , S ₃
...Guide hole.

Claims (1)

[Claims] 1. A shift head is integrally assembled to a fork shaft that is movably assembled to the casing in the axial direction, and a shift fork is assembled so as to be slidable in the axial direction, and a connecting pin is attached to each end of the shift head and shift fork. The other ends of a pair of arms that are rotatably connected to each other are connected through the fork shaft, and the connecting pin is engaged with a guide hole provided in a bracket fixed to the casing. When moving in one direction, the connecting pin moves while being guided by the guide hole, and the shift fork slides on the fork shaft to move in the other direction.