JPS6246938Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a gear transmission switching device suitable for implementation in motorcycles and the like.

(Prior Art) Some motorcycles are equipped with a centrifugal clutch in order to facilitate driving operations. This centrifugal clutch generally has two stages, high speed and low speed, and is widely used. Motorcycles equipped with centrifugal clutches are very convenient to shift gears, but considering the conditions of flat driving and mountainous driving, it would be even more convenient if the final reduction ratio could be changed.

To change the final reduction ratio, you can change the sprocket attached to the rear wheel to one with a different number of teeth, but this is different if you are building a special car for driving on flat or mountainous terrain. When using one motorcycle for both purposes,
It will be difficult in practice. Therefore, even in the past, it has been considered to meet this requirement without replacing the sprocket. For example, a lead groove is formed on the outer periphery of the change cam, and the change cam is positioned by a guide plate attached to the crankcase or case. The change cam was rotated using a gear or link that worked with the change lever.

(Problems to be Solved by the Invention) Such a device has a problem in that it has a complicated structure, is large in size, and is complicated to operate. The present invention was made with the aim of solving this problem.

(Means for Solving the Problems) The present invention is a means for solving the above problems, in which the gear transmission switching device is opposed to the axial tip of the shift rod of the sprocket cover attached to the crankcase. The part is provided with a circular step part protruding outward toward the center of the circle, and a window hole having a flat inner wall part at a predetermined distance behind the step part, while the inner central part is provided with a window hole having a flat inner wall part. It has a cam surface with different heights in the axial direction, and a plane perpendicular to the rotation center on the outside of the cam surface, and a grip portion is integrally formed on the outside portion, and a grip portion is formed on the outer periphery of the grip portion. A knob having a step portion corresponding to the step portion of the window hole and having an outer circumferential shape similar to the window hole is provided, and the knob is inserted from inside the sprocket cover so that the cam surface is brought into contact with the tip of the shift rod. The output shaft is fitted in such a way that the gripping portion is substantially flush with the outer surface of the sprocket cover, and the stepped portion is engaged with the stepped portion of the sprocket cover. A spring is interposed to provide a force for the tip of the shift rod to come into contact with the cam surface of the knob, and the outer periphery is in contact with the inner wall surface of the sprocket cover, and the inner periphery is in contact with the inner wall of the knob. A set plate is provided in contact with a plane of the sprocket cover, and the knob is rotated with respect to the sprocket cover by means of the set plate and a bolt that fastens the set plate to the inner wall of the sprocket cover. It is configured so that it can be held freely.

(Function) With this configuration, by hooking your finger on the handle of the knob from the outside of the sprocket cover and rotating it, the knob will connect to the step formed on its outer periphery and the sprocket cover. The shift rod is rotated while maintaining a constant position by engagement of the stepped portion of the window hole and grip by the set plate with the inner wall of the sprocket cover, and the shift rod in contact with the inner cam surface is displaced in the axial direction. will be possible. Therefore, if the coupling ratio between the counter shaft and the output shaft can be changed by the displacement of the shift rod, it is possible to easily set a gear ratio suitable for both flatland driving and mountainous driving.

(Example) Next, an example of the present invention will be described with reference to the drawings.
First, in FIG. 1, 1 is a crankshaft, 2 is a counter shaft, and 3 is an output shaft. A drive chain 7 is spanned between a sprocket 4 attached to the output shaft 3 and a sprocket 6 attached to the rear axle 5. Two centrifugal clutches 8 and 9 are attached to the crankshaft 1 in parallel, and gears 10 and 1 are attached to the countershaft 2, respectively.
The counter shaft 2 is rotated via the shaft 1. Gear 10 is for high speed, and gear 11 is for low speed. Therefore, a one-way clutch 12 is installed between the gear 11 and the counter shaft 2.

Two gears 1 with different numbers of teeth are mounted on the counter shaft 2.
3 and 14 are attached, and mesh with gears 15 and 16 rotatably supported on the output shaft 3, respectively. Between the gears 15 and 16, the output shaft 3
There is a shifter 17 that moves along the output shaft 3.
Either one of the gears 15 and 16 can be selectively coupled to the gear.

In this gear transmission configured in this manner, the shifter 17 is coupled to either one of the gears 15 and 16 for use. in this case,
When the rotational speed of the crankshaft 1 increases, the centrifugal clutch 9 engages when the rotational speed reaches a certain value, rotating the countershaft 2 via the gear 11, and the gears 14, 16,
The output shaft 3 is rotated via the shifter 17.

When the rotational speed of the crankshaft 1 further increases and reaches a certain rotational speed, the centrifugal clutch 8 is also engaged, causing the countershaft 2 to rotate at an even higher speed via the gear 10. At this time, the one-way clutch 12 is activated, and the gear 11 is connected to the counter shaft 2.
He was forced to idle against the opponent.

In the above operation, if the shifter 17 is moved to the left or right and is coupled to one of the gears 15 and 16, the counter shaft This means that the rotation speed of the output shaft 3 can be changed relative to the constant rotation speed of the output shaft 3.

Therefore, if the shifter 17 can be easily moved from outside the crankcase, the final reduction ratio can be changed as a result.
This means that the same motorcycle can be adapted to both flatland and mountainous driving.

The structure of this part according to the present invention will be explained with reference to FIG. Note that the same members as in FIG. 1 are designated by the same reference numerals, and explanations of those portions will be omitted. 18
is the crankcase. This crank case 1
A crankshaft 1, a countershaft 2, an output shaft 3, and a kickshaft 19 are each rotatably supported on the shaft 8. A sprocket cover 20 is provided on the outside of the crankcase 18, and the aforementioned kick shaft 19 passes through this, and a kick pedal 21 is attached to the tip thereof.

The output shaft 3 is a hollow shaft, into which a shift rod 22 is inserted so as to be movable in the axial direction of the output shaft 3. A spring 23 is interposed inside the output shaft 3 and pushes the shift rod 22 left and right. As a result, the tip of the shift rod 22 always comes into contact with the cam surface 25 on the back surface of the knob 24 rotatably provided on the sprocket cover 20.

The knob 24 has a shape as shown in FIGS. 3 and 4, and as shown in FIG.
The sprocket cover 20 is fitted by engaging with the step 20d of the window hole 20a provided in the sprocket cover 20, and from the inside, the outer periphery is in contact with the inner wall surface 20e of the sprocket cover 20, and the inner periphery is in contact with the inner plane 24a of the knob 24. It is fixed by a set plate 20b and bolts 20c that are in contact with each other. This knob 24 has a cam surface 25 having different heights in the axial direction on one side (inside) and a handle portion 24a on the other side (outside), and has an outer peripheral shape similar to the window hole 20a. This allows the sprocket cover 20 to be rotated by gripping the handle 26a from the outside. When fitting and fixing this knob 24 into the window hole 20a, make sure that the tip of the shift rod 22 is in contact with the cam surface 25 and the handle portion 26a is approximately flush with the outer surface of the sprocket cover 20. Make it. 27 is a ball, and 28 is a spring, which are used to regulate the angle of the knob 24 and provide moderation when rotating.

Holes 29, 30 are provided in a part of the output shaft 3 in parallel with each other in the axial direction, and balls 31,32 are inserted into the holes 29,30. Hole 29.30
A plurality of these are provided radially on the output shaft 3, respectively. The balls 31 and 32 fit into grooves 15a and 16 provided on the inner periphery of the gears 15 and 16, respectively.
It is facing a. Shift rod 22 ball 3
1. In the place facing 32, there is a shift plug 33
is provided.

The shift plug 33 selectively pushes one of the balls 31 and 32 outward in relation to the forward and backward movement of the shift rod 22, thereby coupling one of the gears 15 and 16 to the output shaft 3. It is. The shift rod 22 is connected to the cam surface 2 of the knob 24.
The forward and backward movements are controlled by 5.

The slope of the cam surface 25 of the knob 24 is
When the shift rod 22 is rotated approximately 180 degrees,
It is convenient for use to move a predetermined distance. The knob 24, shift rod 22, shift plug 33, balls 31, 32, etc. constitute the shifter 17 shown in FIG.

In the present invention, the related parts of the gear shift operation knob 24 in the gear transmission switching device are constructed as described above, so that by manually rotating the knob 24 from the outside of the sprocket cover 20, Since the coupling ratio between the counter shaft 2 and the output shaft 3 can be changed via the shift rod 22, the vehicle has the advantage of being able to easily switch between running on flat terrain and running on mountainous terrain. Since the handle portion 24b and the cam surface 25 of the knob 24 are integrally formed on the knob 24, the force applied to the handle portion 24b can immediately push the shift rod 22, which has the advantage of ensuring reliable operation. . Further, the knob 24 has a circular shape similar to the window hole 20a, and the step portion 26 is similar to the window hole 20a.
Since the outer surface is fitted to a so that the outer surface is substantially the same, there is no chance of damage from hitting other objects outside.
Since the knob 24 is fixed from the inside using the set plate 20b and the bolt 20c, no mounting member is exposed to the outside, resulting in an excellent appearance. Furthermore, since the force applied to the knob 24 is received by the stepped portion 20d of the sprocket cover 20, the strength is excellent. Also, unlike levers, they do not take up space and are easy to assemble. In addition, the structure is simple, so it can be made small and lightweight, and
It also has the advantage of being inexpensive. In addition, knob 2
4 does not protrude outward from the sprocket cover 20, so it does not hit other objects, and the steps 20d, 26
This engagement effectively prevents water and dust from entering from the outside.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of one embodiment of the present invention, Fig. 2 is a sectional view showing an example of the one in Fig. 1, and Fig. 3 is a system diagram of an embodiment of the present invention.
FIG. 4 is a front view showing the knob of the one shown in the figure, and FIG. 4 is a side view of the one shown in FIG. 3. 18... Crank case, 20... Sprocket cover, 20a... Window hole, 20b... Set plate, 20c... Bolt, 20d, 26... Step, 20e... Inner wall surface, 22... Shift rod,
23...Spring, 24...Knob, 24a...
...Flat surface, 24b...handle portion.

Claims (1)

[Scope of utility model registration request] The sprocket cover 20 attached to the crankcase 18 has a circular stepped portion 20d protruding outward toward the center of the circular shape at a portion opposing the axial tip of the shift rod 22, and a predetermined portion behind the stepped portion 20d. A window hole 20a having a flat inner wall surface 20e is provided at a distance from the window hole 20a, and a cam surface 25 having different heights in the axial direction is provided at the center of the inside, and a cam surface 25 is provided on the outside of the cam surface 25 and is perpendicular to the center of rotation. surface plane 24a
A grip portion 24b is integrally formed in the outer portion, and the window hole 20 is formed on the outer periphery of the grip portion 24b.
A step portion 26 corresponding to the step portion 20d of a is formed.
A knob 24 whose outer peripheral shape is similar to the window hole 20a.
, the knob 24 is brought into contact with the cam surface 25 against the tip of the shift rod 22 from the inside of the sprocket cover 20, and the grip portion 24b
The stepped portion is attached to the sprocket cover 2 so that it is approximately flush with the outer surface of the sprocket cover 20.
The tip of the shift rod 22 is fitted into the output shaft 3 by engaging with the stepped portion of the knob 2.
A spring 23 that applies a force to contact the cam surface 20e of 4 is interposed, and inside the knob 24,
The outer circumferential portion is in contact with the inner wall surface of the sprocket cover 20, and the inner circumferential portion is in contact with the inner plane 24 of the knob 24.
A set plate 20b is provided in contact with the sprocket cover 20.
The knob 24 is attached to the sprocket cover 20 by a bolt 20c fastened to the inner wall surface 20e of the sprocket cover 20.
A switching device for a gear transmission, characterized in that the gear transmission is gripped so as to be rotatable.