JPH0799194B2 - Gear change device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change device suitable for a vehicle speed change mechanism.

2. Description of the Related Art Conventionally, a plurality of sets of transmission gear trains having different rotation ratios are provided between a drive shaft and a driven shaft, and any one of these transmission gear trains is desired to be selectively engaged with the driven shaft. In the speed change device that obtains rotation transmission according to the speed ratio, a sliding gear, a dock clutch, a synchromesh, a hydraulic multi-plate clutch, or the like is used as the selectively connecting means.

Among these selective coupling means, the dock clutch is widely adopted because it has a simple structure, is low in cost, and can reliably transmit rotation.

However, it is not easy to disengage the driving-side claw and the driven-side claw of the dock clutch from the rotation transmission state of the driving force, and the claw must be disengaged after the rotation is temporarily stopped. I have to. Therefore, when the dock clutch is used as a gear shift device for a vehicle, the gear shift operation can be performed only after the traveling of the vehicle is temporarily stopped.

On the other hand, when the hydraulic multi-plate clutch is used, the power transmission can be intermittently performed smoothly, but there is a drawback that the gear change device becomes large and the cost becomes high.

Means for Solving the Problems A first passive gear that is constantly driven to rotate and a second passive gear that is driven to rotate at a different rotational speed from the first passive gear based on a gear shift operation are rotatably mounted on a driven shaft. A passive gear clutch claw is radially formed on the side surface portion of the first passive gear while being externally fitted to form a cam claw that engages with the passive gear clutch claw in a disengageable manner, and is integrally formed with the second passive gear. A rotating cam claw body is provided slidably in a direction in which the cam claw and the passive gear clutch claw engage and disengage, and has a clutch claw that engages with the passive gear clutch claw in a disengageable manner. A clutch pawl that urges the cam pawl in the direction in which it meshes with the gear clutch pawl and urges the cam pawl in the direction in which the cam pawl meshes with the passive gear clutch pawl slides on the driven shaft. A connecting portion is provided for connecting the cam claw body and the clutch claw body integrally and rotatably when the second passive gear is rotationally driven.

Further, a convex portion is provided on the outer peripheral portion of the cam pawl body, and the convex portion is inserted into the groove portion of the clutch pawl to integrally and rotatably connect the cam pawl body and the clutch pawl body.

Action In the normal power transmission state, only the first passive gear is driven to rotate, and the clutch pawl is integrated with the first passive gear by the engagement of the passive gear clutch pawl of the first passive gear and the clutch pawl of the clutch pawl. Driven rotationally, and the driven shaft to which this clutch pawl is spline fitted is rotationally driven. The cam pawl of the cam pawl engages with the passive gear clutch pawl, and the cam pawl and the second passive gear rotate integrally with the first passive gear.

When a gear change operation for rotationally driving the second passive gear is performed, the first passive gear is also continuously rotationally driven, and the rotational speed of the second passive gear is different from the rotational speed of the first passive gear. Therefore, a difference occurs between the rotation speed of the cam pawl that rotates integrally with the second passive gear and the rotation speed of the first passive gear, and due to this difference in rotation speed, the cam pawl becomes the first passive gear. The cam pawl slides in a direction in which the cam pawl and the passive gear clutch pawl are disengaged by rotating relative to each other and riding on the passive gear clutch pawl.
As the cam claw body slides, the clutch claw body pushed by the cam claw body also slides in the direction in which the engagement between the clutch claw and the passive gear clutch claw is released.

When the cam pawl and the passive gear clutch pawl are disengaged, the clutch pawl and the passive gear clutch pawl are also disengaged, and then the cam pawl and the clutch pawl that rotate integrally with the second passive gear. Are connected by the connecting portion, and the clutch pawl and the cam pawl rotate integrally. As a result, the driven shaft rotates integrally with the second passive gear.

When the gear shift operation is performed to cut off the transmission of the driving force to the second passive gear, the driving force transmitted from the second passive gear to the cam pawl is lost, so the cam force is applied by the clutch pawl. The claw body and the clutch claw body slide, and the cam claw and the clutch claw mesh with the passive gear clutch claw.
Then, the driven shaft is rotationally driven by the driving force from the first passive gear due to the engagement between the clutch pawl and the passive gear clutch pawl.

Further, when the convex portion provided on the outer peripheral portion of the cam pawl is inserted into the groove portion of the clutch pawl, the convex portion abuts the side surface of the groove portion when the second passive gear is driven, so that the cam pawl body and the clutch pawl body are Are integrally and rotatably connected.

Embodiment An embodiment of the present invention will be described with reference to the drawings. A clutch case 1 and a mission case 2 are provided on the abdomen of the tractor, and a transmission case 4 is attached below the clutch case 1 and in front of the mission case 2 with bolts 3. The transmission case 4 has an input gear 6 rotatably supported by a bearing 5, an output shaft 8 as a driven shaft rotatably supported at one end by a bearing 7, and a shaft center parallel to the output shaft 8. In addition, a counter shaft 11 supported by bearings 9 and 10 is housed therein. The input gear 6 is spline-fitted to the front end of a front wheel power take-off shaft 12 extending from the transmission case 2 into the transmission case 4. The end is rotatably held. Also, the output shaft 8
A front wheel power transmission shaft 14 is connected to the tip end of the through a cylindrical joint 13.

A counter gear 15 meshed with the input gear 6 is spline-fitted to the outer peripheral portion of the counter shaft 11, and a high-speed side transmission gear 16 is rotatably externally fitted and a low-speed side transmission gear 17 is spline-fitted. Has been done. A clutch body 18 is slidably fitted on the outer peripheral portion of the counter shaft 11 so as to be located between the counter gear 15 and the high speed side transmission gear 17. A clutch pawl 19 is formed on the clutch body 18, and a clutch pawl 20 that meshes with the clutch pawl 19 is formed on the side surface of the high speed side transmission gear 16 so as to engage with and disengage from the clutch pawl 19. And these clutch claws 1
The clutch body 18 is moved in the direction in which 9, 20 are disengaged from each other.
A spring 21 for urging the counter shaft 11 is provided on the outer peripheral portion of the counter shaft 11, and a shifter fork 22 for forcibly sliding the clutch body 18 in a direction in which the clutch pawls 19 and 20 mesh with each other is provided. The shifter fork 22 is connected to a shifter shaft 23 that penetrates the transmission case 4, and a lever 24 is connected to one end of the shifter shaft 23 protruding outside the transmission case 4. The lever 24 is connected to a solenoid 26 via a link mechanism 25.

Then, on the outer peripheral portion of the output shaft 8, the high speed side transmission gear is provided.
A high-speed side passive gear 27, which is a second passive gear meshing with 16, is rotatably fitted over the boss portion 28 of the high-speed side passive gear 27.
A low speed side passive gear 29, which is a first passive gear meshing with the low speed side transmission gear 17, is rotatably fitted around the outer periphery of the low speed side transmission gear 17, and a passive gear clutch claw 30 is radially provided on one side of the low speed side passive gear 29. Is formed in. A clutch claw body 32 is slidably spline-fitted to a spline portion 31 formed on the output shaft 8. The clutch claw body 32 is disengageable from the outer peripheral side of the passive gear clutch claw 30. A clutch pawl 33 that meshes is formed, and a spring 34 that urges the clutch pawl body 32 in a direction in which the clutch pawl 33 and the passive gear clutch pawl 30 mesh with each other is provided on the outer peripheral portion of the output shaft 8. .

A spline portion 35 is formed on the outer periphery of the boss portion 28 on the tip side, and a cam claw 36 is slidably fitted to the spline portion 35. On one side of the cam pawl 36 facing the low-speed side passive gear 29, a cam pawl that engages with the inner peripheral side of the passive gear clutch pawl 30 in a disengageable manner.
37 is formed, and the cam claw 37 is formed with an inclined portion 38 having a width narrowed toward the top side. The clutch pawl 32 is in contact with the other side of the cam pawl 36, and the cam pawl 36 has a cam pawl 37 and a passive gear clutch pawl 30 that are urged by the spring 34. It is urged in the direction of engagement. A convex portion 39 is formed on the outer peripheral portion of the cam pawl body 36, and the convex portion 39 is inserted into the groove portion 40 of the clutch pawl 33. And this convex part
The groove 39 and the groove 40 constitute a connecting portion 41 that integrally rotatably connects the cam pawl 36 and the clutch pawl 32 when the high-speed side passive gear 27 is rotationally driven.

Here, as shown in FIG. 1 and FIG. 6A, the clutch claw 33 and the cam claw 37 mesh with the passive gear clutch claw 30, and the low speed side passive gear 29, the clutch claw body 32, and the cam claw 37. body
As shown in FIGS. 6 (a) and 7 (a), a gap having an angle “A” is formed between the convex portion 39 and the clutch pawl 33 when the gear 36 and the clutch 36 are integrally rotated. Is provided. Further, as shown in FIGS. 2 and 6 (c) and (d), the clutch pawls 19 and 20 are engaged with each other and the engagement of the clutch pawl 33 and the cam pawl 37 with the passive gear clutch pawl 30 is released. After that, as shown in FIGS. 6 (c) and 6 (d) and FIGS. 7 (c) and 7 (d), the convex portion 39 has the clutch claw 33.
Abut the side surface of. At this time, the clearance angle "A" is set so that the angle "B" formed by the top of the clutch claw 33 and the top of the cam claw 37 in succession is larger than the angle "C" of the groove of the passive gear clutch claw 30. It is set.

In such a configuration, the rotation of the front wheel power output shaft 12 is
It is transmitted to the counter shaft 11 via the input gear 6 and the counter gear 15. Here, as shown in FIG. 1, the spring
In the state where the clutch body 18 slides due to the urging force of 21, and the engagement between the clutch pawls 19 and 20 is released, only the low-speed side transmission gear 17 rotates integrally with the counter shaft 11, and the counter shaft 11 Rotation is done by low speed side transmission gear 17, low speed side passive gear 29, passive gear clutch claw 30, clutch claw 3
3, transmitted to the output shaft 8 via the clutch pawl 32, and further transmitted to the front wheel power transmission shaft 14 via the joint 13. Then, the front wheels (not shown) of the tractor are rotationally driven at a low speed by the rotation of the front wheel power transmission shaft 14.

Next, when a shift change operation for operating the solenoid 26 is performed, the clutch body 18 slides against the urging force of the spring 21 via the link mechanism 25, the lever 24, the shifter shaft 23, and the shifter fork 22, and the second Clutch 19,20 as shown
The two bite together. Then, the rotation of the counter shaft 11 is transmitted to the cam pawl body 36 via the clutch body 18, the clutch pawls 19, 20, the high speed side transmission gear 16, and the high speed side passive gear 27, and the cam pawl body 36 is rotated.
36 rotates integrally with the high speed side passive gear 27. On the other hand, the rotation of the counter shaft 11 is continuously transmitted to the low-speed side passive gear 29 via the low-speed side transmission gear 17, and the cam claw body 36 is integrated with the low-speed side passive gear 29. The force that tries to rotate acts. Here, the rotational speed of the cam claw 36 is reduced by the power transmission from the high-speed side passive gear 27.
The rotational speed becomes higher than the rotational speed of 29, and a difference in rotational speed occurs between the passive gear clutch pawl 30 and the cam pawl 37. Therefore, the passive gear clutch claw 30 abuts the inclined portion 38 of the cam claw 37 due to the difference in the number of revolutions, the cam claw 37 rides on the passive gear clutch claw 30, and the cam claw body 36 separates from the low-speed side passive gear 29. 7B, the cam claw body 36 slides in the direction in which the engagement between the cam claw 37 and the passive gear clutch claw 30 is released, as shown in FIG. 7B. At the same time, the clutch pawl 32 pushed by the cam pawl 36 also slides integrally against the biasing force of the spring 34, and the engagement between the clutch pawl 33 and the passive gear clutch pawl 30 is released.

Clutch pawl 33 and cam pawl 37 for passive gear clutch pawl 30
After the engagement with is released, the cam pawl 36 that rotates integrally with the high-speed side passive gear 27 rotates by the angle "A" in the direction of the arrow "D", and then, as shown in FIG. (D) and 7th
As shown in FIGS. (C) and (d), the convex portion 39 contacts the side surface of the clutch pawl 33. As a result, the clutch pawl 32 driven by the cam pawl 36 rotates integrally with the cam pawl 36, and the rotation of the high speed side passive gear 27 is performed via the cam pawl 36 and the clutch pawl 32. Transmitted to the output shaft 8, and
It is transmitted to the front wheel power transmission shaft 14 via 13. Then, the front wheels of the tractor are rotationally driven at a high speed by the rotation of the front wheel power transmission shaft 14.

Further, in the state where the convex portion 39 is in contact with the side surface of the clutch claw 33, FIGS. 6 (c) and 6 (d) and FIG. 7 (c),
As shown in (d), the angle “B” formed by the top of the clutch pawl 33 and the top of the cam pawl 37 is the passive gear clutch pawl.
It becomes larger than the angle “C” of the groove of 30. Therefore, at least one of the top of the clutch pawl 33 and the top of the cam pawl 37 is always kept in contact with the top of the passive gear clutch pawl 30. Therefore, even if the clutch pawl 32 and the cam pawl 36 are biased toward the low-speed side passive gear 29 by the spring 34, the clutch pawl 33 and the cam pawl 37 are prevented from repeatedly engaging and disengaging from the passive gear clutch pawl 30. As a result, noise and wear due to repeated engagement and disengagement are prevented.

When the solenoid 26 is deactivated, the shifter fork 22
The pressing of the clutch body 18 by the clutch is released, and the clutch body 18 slides by the urging force of the spring 21 and the clutch pawl 1
The meshing of 9, 20 is released, and the transmission of the driving force from the high speed side transmission gear 16 to the high speed side passive gear 27 is cut off. Therefore, the contact force of the convex portion 39 on the side surface of the clutch pawl 33 disappears, and the friction force between the top of the passive gear clutch pawl 30 and the top of the cam pawl 37 causes the cam pawl body 36 to move at a slower speed than the clutch pawl body 32. As it rotates, as shown in FIG. 7 (e), the angle formed by the top of the cam pawl 37 and the top of the clutch pawl 33 continuously becomes smaller, and becomes smaller than the angle “C” of the groove portion of the passive gear clutch pawl 30. 7 (f), the cam claw 37 and the clutch claw 33 mesh with the passive gear clutch claw 30 by the urging force of the spring 34. As a result, the rotation of the counter shaft 11 is transmitted to the output shaft 8 via the low speed side passive gear 29 and the clutch pawl 32, and the front wheel power transmission shaft is transmitted.
14 is driven via the joint 13, and the front wheels are rotationally driven again at a low speed.

In the present embodiment, the low-speed transmission state is normally set, and the low-speed side power transmission is temporarily cut off only during high-speed transmission, but the high-speed side transmission gear 16 and the high-speed side passive gear 27 have a gear train. By replacing the low-speed side transmission gear 17 and the low-speed side passive gear 29 with the gear train,
It is also possible to set the high-speed transmission state during normal operation and temporarily cut off the power transmission on the high-speed side only during low-speed transmission.

As described above, according to the present invention, the clutch pawl of the clutch pawl body and the cam pawl of the cam pawl body are engaged with the passive gear clutch pawl of the first passive gear when shifting is performed by driving only the first passive gear as described above. And the cam pawl and the clutch pawl are engaged due to the difference in rotational speed between the first passive gear and the second passive gear during gear shifting when the first passive gear and the second passive gear are rotationally driven. Passive gear Sliding the cam pawl and clutch pawl to a position where the engagement with the clutch pawl is released, and rotating integrally with the second passive gear The cam pawl and clutch pawl rotate integrally by the connecting portion. By freely connecting, the power transmission from the first passive gear to the driven shaft via the clutch pawl when driving only the first passive gear and driving the first passive gear and the second passive gear Second passive gear when allowed to Can smoothly and swiftly switch between power transmission to the driven shaft from the cam pawl body and the clutch pawl body, and at the time of power transmission from the first passive gear and from the second passive gear. Since both the clutch pawl is used as a power transmission member during power transmission, the number of parts can be reduced and the structure can be simplified.Furthermore, the convex portion formed on the outer peripheral portion of the cam pawl can be used for the clutch pawl. By connecting the cam claw body and the clutch claw body by inserting the cam claw body into the groove portion, a convex portion or a groove portion is formed so that the driving force can be transmitted from the cam claw body to the clutch claw body at a portion having a large diameter. It is possible to reduce the size of the clutch claws, and moreover,
As compared with a speed change device using a hydraulic multi-disc clutch or a synchromesh, the size and cost can be reduced.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a bottom view showing a power transmission state through a low speed side passive gear in section, and FIG. 2 shows a power transmission state through a high speed side passive gear. FIG. 3 is a bottom view showing a section, FIG. 3 is a front view showing a cam claw body,
FIG. 4 is a vertical sectional side view showing a cam pawl body, FIG. 5 is a side view showing a mounting state of a transmission case, FIG. 6 is a front view showing a meshing state of a clutch portion, and FIG. 7 is a meshing state of a clutch portion. It is a development view showing a state. 8: driven shaft, 27: second passive gear, 29: first passive gear, 30: passive gear clutch pawl, 32 ... clutch pawl,
33 …… Clutch claw, 36 …… Cam claw body, 37 …… Cam claw, 39
...... Convex part, 40 ...... Groove part, 41 ...... Connecting part

Claims (2)

[Claims] 1. A first passive gear, which is constantly driven to rotate, and a second passive gear, which is driven to rotate at a different rotational speed from the first passive gear based on a gear shift operation, are rotatably fitted on a driven shaft. In addition, radially forming passive gear clutch pawls on the side surface of the first passive gear, a cam pawl that engages with the passive gear clutch pawl in a disengageable manner is formed, and rotates integrally with the second passive gear. A cam pawl is provided slidably in a direction in which the cam pawl and the passive gear clutch pawl are disengaged, and has a clutch pawl that engages with the passive gear clutch pawl in a disengageable manner. The clutch pawl and the passive gear clutch A clutch pawl that biases the cam pawl in a direction in which the cam pawl engages with the passive gear clutch pawl is slidably slid onto the driven shaft. Fitted, gear shifting devices and characterized in that a connecting portion integrally rotatably connected the cam pawl body when the second passive gear is driven rotation of said clutch pawl. 2. A cam claw body is provided with a convex portion on an outer peripheral portion thereof, and the convex portion is inserted into a groove portion of the clutch pawl so that the cam pawl body and the clutch pawl body are integrally and rotatably connected. The gear change device according to claim 1, wherein