JPS62215151A - Rotary change mechanism - Google Patents

Abstract

PURPOSE:To prevent uncomfortable feeling due to sudden speed reduction by providing a swelled-out part on the top engaging pin of the rotary change mechanism of a motorcycle and enabling a driver to sense that a speed change stage is shifted to a neutral when shifting said speed change stage from a top gear to the neutral in the direction of the first gear. CONSTITUTION:A neutral engaging pin 10 corresponding to each speed change stage, a first gear engaging pin 11, a second gear engaging pin 12, a third gear engaging pin 13, and a top gear engaging pin 14 are provided while being projected in the axial direction at an equal angle pitch, on a change drum which is rotatably supported by a transmission case. And, a swelled-out part 14b which swells out toward the neutral engaging pin 10 is provided on the engaging pin 14. Thereby, only when a first engaging part 23a is engaged with a top engaging pin 14, the rotation angle of a shift shaft 19 is small, without causing a centrifugal clutch to be disconnected. Accordingly, since the foot pressing force of a shift pedal is larger than that for other shifts, a driver can easily sense the neutral.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary change mechanism that is mainly used in motorcycles and the like and shifts a transmission in conjunction with the rotation of a change drum.

[Prior Art] Conventionally, for example, a transmission is provided with a transmission that is shifted to first gear, second gear, and top gear, and a change drum shifts from a first gear position to a second gear position and a top gear position corresponding to each gear stage. There are two-wheeled motor vehicles equipped with a rotary change mechanism that sequentially rotates between positions (for example, Japanese Patent Laid-Open No. 57-13848
(See Publication No. 4).

[Problems to be Solved by the Invention] With this type of change mechanism, when the vehicle is traveling, due to an erroneous operation from the top position, etc., the vehicle may be inadvertently shifted from the neutral position to the first speed position.

As a result, a large engine brake is applied, which may make the driver feel uncomfortable.

This invention was made in view of the above-mentioned conventional problems.
By making the driver aware of this when the gear shifts from top gear to first gear and entering neutral, the risk of inadvertently shifting from top gear to first gear is eliminated, and the discomfort caused by this is reduced to the driver. The purpose of this invention is to provide a rotary change mechanism that does not cause any damage to the vehicle.

[Means for Solving the Problems] In order to achieve the above object, the present invention disengages the clutch as the shift shaft rotates by manual operation. On the other hand, the change drum is provided with engagement pins that protrude in the axial direction, corresponding to each gear stage of the transmission. The shift pole, which rotates in conjunction with the shift shaft, engages with the engagement pin and rotates the change drum. Among the engagement pins, the top engagement pin corresponding to the top position is formed with a bulge portion that bulges toward the neutral side engagement pin. The shift pawl engages with the bulge before the clutch is disengaged when rotating the change drum from the top position to the neutral position.

[Operation] According to the present invention, the shift pole, which rotates in conjunction with the shift shaft that disengages the clutch, engages with the engagement pin corresponding to each gear stage and rotates the change drum, so that the shift operation is not performed. is done during clutch disengagement.

On the other hand, when the change drum is rotated from the top position to the neutral position, the shift pawl engages with the bulge of the top engagement pin that bulges out toward the neutral side engagement pin before the clutch is disengaged. This increases the operating force required for manual operation. Therefore, the driver can sense that the shift operation in that case is from top to neutral.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the transmission and rotary change mechanism in neutral, and 1 is a transmission case. The mission case 1 is formed integrally with a crankcase (not shown), and rotatably supports a counter shaft 2 and a power take-off shaft 3.

The countershaft 2 has four variable speed drive gears 4A.
, 4B, 4C, and 4D are arranged, and an output extraction gear 5 for transmitting driving force from a crankshaft (not shown) via a centrifugal clutch (not shown) is fixed to the end thereof. On the other hand, the power take-off shaft 3 is provided with the variable speed drive gears 4A and 4B.

Shift driven gears 6A and 6B mesh with 4C and 4D, respectively.
, 6C, and 6D are arranged to form a transmission T.

In this transmission T, a speed change driving gear 4B and a speed change driven gear 6C are connected to both shafts 2.3 by splines 2a and 3a, respectively.
and by moving these in the axial direction, the gears are shifted from neutral to first gear, second gear, third gear, and top gear.

A change drum 7 is rotatably supported by the transmission case 1, and has two cylindrical cams 7a and 7b carved on its outer periphery.

Shift forks 8A and 8B are axially engaged with 7b, respectively. This shift fork 8A.

The shaft 9 fixed to the transmission case l is inserted into the shaft 9B, and the shift drive gear 4B and the shift driven gear are inserted into the tips m(7) of the shift forks 8A and 8B (7) pawls 8Aa and 8Ba, respectively. 6C is engaged. The shift forks 8A and 8B are interlocked with the rotation of the change drum 7 by the action of the cylindrical cams 7a and 7b, and the two gears 4B are engaged with each other.

6C in the axial direction to shift the transmission T.

The change drum 7 includes a neutral engagement pin 10 corresponding to each gear stage, a first gear engagement pin 11, a second gear engagement pin 12, and a third gear engagement pin 12 shown in FIG. 2, which shows the main parts in the first gear state. 3
A quick locking pin 13 and a top engaging pin 14 are provided to protrude in the axial direction at equal angular pitches. Reference numeral 15 denotes a detachment prevention fitting, and the engagement pins 10, 11. , l 2
, 13.

14 from coming off in the axial direction, it is screwed to the change drum 7 shown in FIG. 1, and has a cap-like shape.

The top engaging pin 14 includes a cylindrical portion 14a and a protruding portion 14c having a semicircular cross section. This top engagement pin 14 has a columnar part 14a rotatably supported by the change drum 7, and a protruding part 14c having a semicircular cross section protruding from a locking hole 15a provided in a detachment prevention fitting 15. As will be described later, the rotation angle is regulated, and the end surface of the bulging portion 14b comes into contact with the inner surface 15b of the detachment prevention fitting 15, thereby preventing its detachment in the axial direction. As shown in FIG. 2, the locking hole 15a has a fan shape with a central angle larger than 1800 degrees. The top engaging pin 14 has a bulging portion 1
4b rotates in the direction of arrow A in the locking hole 15a by the rotational force due to its own weight, and the bulging portion 14b is bulged toward the neutral engagement pin 10 at the top position in FIG.

On the other hand, the other engaging pins 10, 11, 12, 13 are simply cylindrical, and the inner surface 15b of the detachment prevention fitting 15 in FIG.
to prevent it from coming off in the axial direction,
Like the top engagement pin 14, it is pivotally supported by the change drum 7.

In Fig. 1, reference numeral 16 denotes a positioning lever, which is rotatably attached to a stepped bolt 17 screwed into the transmission case 1, and is constantly provided with rotational force by the spring 18 shown in Fig. 2 fixed to the transmission case 1 side. energized. Due to the moment about this stepped bolt 17, the positioning lever 16 comes into contact with two, for example, retaining pins 10.11, and positions the change drum 7 in the circumferential direction of FIG. 1 at each gear stage. do. In other words, the axial positions of the shift forks 8A, 8B and the gears 4B, 6C that engage with these at each gear stage are determined.

Reference numeral 19 denotes a shift shaft, which is rotatably supported by the transmission case 1 and is rotated by manual operation such as by stepping on a shift pedal (not shown), and in conjunction with this rotation, the centrifugal clutch is disengaged. . 20 is the shift lever
An angle regulating pin 2 is fixed to the shift shaft 19 so as to rotate integrally therewith, and is fixed to the transmission case 1.
1 is a notch 20a provided in the shift lever 20 of FIG.
The rotation angle is regulated. This shift lever 20 is returned to the neutral position shown by the solid line when the return spring 22 comes into contact with the bent portion 20b of the shift lever 20.

A shift pole 23 is rotatably supported at the end of the shift lever 20 via a pin 24, a spring 25 is provided between it and the shift lever 20, and the shift pole is operated in conjunction with the shift shaft 19. On the other hand, this shift pole 23 has respective engagement pins io and it.

12.13.14, the change drum 7 shown in FIG. 1 and the detachment prevention metal fitting 15 are always in contact with each other, and their rotation locus is determined. The shift pole 23 in FIG. 2 has a first engaging portion 23a and a second engaging portion 23a that engage with each of the engaging pins 10...14 and enable the change drum 7 (FIG. 1) to rotate.
An engaging portion 23b is provided in a protruding manner. That is, the shift pawl 23 has two re-engaging parts 23a and 23b, respectively.
As shown by the dot-dashed line and the dot-dashed line, the engagement pin 11°1
0 and rotates, the change drum 7 shown in FIG. 1 is rotated.

When the change drum 7 is rotated from the top position shown in FIG. 3 to the neutral position, before the clutch is disengaged by rotation of the shift shaft 19 shown in FIG.
The first retaining portion 23a of the shift pawl 23 shown in the figure comes into contact with the bulging portion 14b that has bulged out toward the neutral engagement pin 10 side due to its own weight.

Next, the operation of the above configuration will be explained.

When shifting the gear stage from 1st gear to the acceleration side, that is, when rotating the change drum 7 in Figure 1 from the 1st gear position to the 2nd gear position in Figure 2, the shift is performed by foot operation of the shift pedal. The shaft 19 rotates in the direction of arrow B, and as a result, the shift lever 20 and shift pawl 23
rotate in conjunction. This rotation causes the shift pole 2
The first retaining portion 23a of No. 3 engages with the first speed engagement pin 11, and in this engaged state, the first speed engagement pin 11 is further rotated and moved close to the neutral engagement pin 10. . Then, as the shift lever 20 returns to the neutral position due to the reaction force of the return spring 22, the shift pawl 23 returns to the neutral position shown by the solid line. At the same time, the first speed retaining pin 11, which has moved close to the neutral engagement pin IO, is pressed by the positioning lever 16 and is positioned at the position of the neutral engagement pin IO.

As the change drum 7 shown in FIG. 1 rotates with the above rotational movement, the cylindrical cam 7a.

Under the action of 7b, shift fork 8A.

8B moves in the axial direction. This movement puts you in gear 4B.

6C is moved in the axial direction, and the transmission T is shifted to second gear. On the other hand, the first engaging portion 23a in FIG.
Immediately before engaging the speed locking pin 11, the shift shaft 1
Since the centrifugal clutch is disengaged with the rotation of 9, the shift described above is performed smoothly. Therefore, the driver's foot operation force is light.

In this way, a shift from neutral to first speed or top speed is performed, while a shift to the deceleration side is performed by rotation in the opposite direction.

By the way, when the change drum 7 shown in FIG. 1 is at the top position shown in FIG. 3, it may be inadvertently rotated through the neutral position to the first speed stirrup.

In contrast, in the present invention, the top engagement pin 14 is provided with a bulge portion 14b that bulges toward the neutral engagement pin 10. Therefore, the rotation angle of the shift shaft 19 in FIG. is in a small state, so that the centrifugal clutch can be kept in a state where it is not disengaged when it is engaged. On the other hand, in this unblocked state, the gears 4B and 6C move via the change drum 7 and shift forks 8A and 8B. As a result, the foot operation force on the shift pedal becomes greater than during other shifts, so the driver can easily sense that the transmission T is in neutral. Therefore, it is possible to effectively prevent the gear from being shifted to $1 gear inadvertently.
There is no risk of causing discomfort to the driver due to sudden deceleration.

FIG. 4 shows a state in which the shift pawl 23 moves the neutral engagement pin 10 and then returns to the neutral position of the shift pawl 23 itself in a state where the gear stage has been shifted from the first speed to the neutral position. Here, since the top engaging pin 14 is provided with the bulging portion 14b, the second engaging portion 23b of the shift pawl 23 comes into contact with this bulging portion 14b. Therefore, it is considered that the smooth movement of the shift pole 23 is hindered.

In contrast, in this embodiment, the detachment prevention fitting 15 has a diameter of 180 mm.
Since the fan-shaped locking hole 15a having a center angle larger than 0 is provided, the protruding portion 14c with a semicircular cross section is attached to the locking hole 15.
Turn inside a in the direction of arrow C and escape. Therefore, the shift pole 23 can operate smoothly. In addition, the protrusion 14c
Due to the circumferential locking between the locking hole 15a and the locking hole 15a, the bulging portion 14
The direction of b is regulated.

FIG. 5 shows a modification of the top engaging pin 14, the detachment prevention fitting 15, and the shift pawl 23. In this figure, the top engagement pin 14 is connected to the change drum 7.
The cylindrical portion 14a is pivotally supported by the cylindrical portion 14a, and the first
The bulging part 14b that the second engaging part 23a engages with, the cylindrical part 14d that the second engaging part 23b engages with, and the semicircular protruding part 1
It consists of 4c. The locking hole 15c of the detachment prevention fitting 15 has a semicircular shape that fits into the protrusion 14c, and the top engaging pin 1
4 rotation is prevented. On the other hand, the shift pawl 23 is bent in the axial direction, and the re-engaging parts 23a and 23b are located at different axial positions.

According to this modification, the bulging portion 14b and the second engaging portion 23
Since the axial position with respect to b is shifted, as shown in Fig. 4,
The second engaging portion 23b never comes into contact with the bulging portion 14b.

[Effects of the Invention] As explained above, according to the present invention, the top engagement pin is provided with a bulge, so that the clutch is engaged only when the gear is shifted from the top gear to the first gear and into neutral. Since the change drum is rotated before the shift is interrupted, only the foot operation force at this time is greater than during other shifts. Therefore, the driver can easily notice that the gear position has been shifted from top to neutral. therefore,
Since there is no risk of the vehicle being shifted to first speed inadvertently, there is no risk of causing discomfort to the driver due to sudden deceleration.

In addition, when the vehicle is stationary or when driving at low speeds, where there are many opportunities to shift from top to neutral,
Generally, the engine speed is low, at which the centrifugal clutch does not operate, so the foot operation force is not large, and the device can be easily operated like the conventional device.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view in neutral of an embodiment of the present invention, and FIG. 2 corresponds to a cross section taken along the line ■-■ in FIG.
Figure 3 is a vertical cross-sectional view of the main parts in the fourth gear position, Figure 4 is a vertical cross-sectional view showing the state of the shift pole returning to the neutral position in the neutral position, and Figure 5 is a modified version. It is a longitudinal cross-sectional view showing the main part of an example. 7... Change drum, 10, 11, 12° 13.1
4... Engagement pin, 10... Neutral side engagement pin (neutral engagement pin), 14... Trough engagement pin, 19... Shift shaft, 23... Shift pole.

Claims (1)

[Claims] (1) A rotary change mechanism that shifts the transmission in conjunction with the rotation of the change drum, which includes a shift shaft that is rotated by manual operation and disengages the clutch with this rotation, and an axial direction from the change drum. an engagement pin that is provided protruding from and corresponds to each gear stage, a shift pole that rotates in conjunction with the shift shaft and engages with the engagement pin to rotate the change drum, and the engagement pin. The top engagement pin corresponding to the top position is formed to bulge out toward the neutral side engagement pin,
A rotary change mechanism comprising: a bulge with which the shift pawl engages before the clutch is disengaged when the shift pawl rotates the change drum from a top position to a neutral position.