JPH0799193B2 - 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 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. The cam claw top is fitted with a spline, and a convex portion inserted into the groove portion of the clutch pawl is provided on the outer peripheral portion of the cam pawl body, and the convex portion abuts on the side surface of the groove portion of the clutch pawl. And the top of the clutch pawl are continuously set to be larger than the rotation direction angle of the groove of the passive gear clutch pawl, and the cam pawl is formed with an inclined portion whose width becomes narrower toward the top. At the same time, the top end surface of the cam pawl is located closer to the passive gear clutch pawl than the top end surface of the clutch pawl.

Further, an urging body for urging the cam pawl body in a direction in which the top of the cam pawl and the top of the clutch pawl are rotated is interposed between the cam pawl and the clutch pawl.

Action In the normal operation transmission state, only the first passive gear is rotationally driven, 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 claw and the passive gear clutch claw are disengaged, the clutch claw and the passive gear clutch claw are also disengaged, and then the convex part of the cam claw body that rotates integrally with the second passive gear is released. The cam claw body and the clutch claw body rotate integrally as they come into contact with the side surfaces of the groove of the clutch claw. This allows
The driven shaft rotates integrally with the second passive gear, and the shift change is completed. At this time, since the rotation direction angle formed by the top of the cam pawl and the top of the clutch pawl is set to be larger than the rotation direction angle of the groove portion of the passive gear clutch pawl, the tip end surface of the cam pawl and the clutch pawl are One of the top end surfaces abuts on the top end surface of the passive gear clutch pawl to prevent the cam pawl and the clutch pawl from repeatedly engaging and disengaging from the passive gear clutch pawl.

When the gear shift operation is performed to cut off the transmission of the driving force to the second passive gear, the contact force of the convex part on the groove side surface of the clutch claw disappears and the passive gear clutch claw abuts the inclined part of the cam claw, The cam claw body rotates in the direction in which the top of the cam claw and the top of the clutch claw overlap, and eventually the continuous rotation angle between the top of the cam claw and the top of the clutch claw becomes smaller than the rotation angle of the groove part of the passive gear clutch claw. Then, the cam claw and the clutch claw mesh with the passive gear clutch claw, and the driven shaft again rotates integrally with the first passive gear.

Further, by interposing an urging body that urges the cam claw body in the direction in which the top of the cam claw and the top of the clutch claw overlap, the cam claw in the direction in which the top of the cam claw and the top of the clutch claw overlap with each other. The rotation of the body is promoted, and therefore, the engagement of the cam pawl and the clutch pawl with the passive gear clutch pawl is promoted, so that the transmission of the driving force to the second passive gear is interrupted, so that the speed change is quickly performed. .

Embodiment An embodiment of the present invention will be described with reference to the drawings. A clutch case 2 and a mission case 3 are provided on the abdomen of the tractor 1, and a transmission case 5 is attached by a bolt 4 below the clutch case 2 and in front of the mission case 3. In the transmission case 5, there are an input shaft 8 rotatably supported by bearings 6 and 7, and a driven shaft having an axis parallel to the input shaft 8 and rotatably supported by bearings 9 and 10. The output shaft 11 and are housed. A front wheel power take-off shaft 13 supported by a bearing 12 in the mission case 3 is connected to a tip end portion of the input shaft 8 via a tubular joint 14, and a tip end portion of the output shaft 11 is connected to the front end portion. Is connected to a front wheel power transmission shaft 16 via a tubular joint 15.

A high speed side transmission gear 17 is rotatably fitted on the outer peripheral portion of the input shaft 8 and a low speed side transmission gear 18 is spline fitted thereto. A clutch body 19 is slidably fitted on the outer peripheral portion of the input shaft 8 between the bearing 6 and the high speed side transmission gear 17 in a slidable manner. A clutch claw 21 is formed on the side surface of the high speed side transmission gear 17 so as to engage with the clutch claw 20 in a disengageable manner. Then, a spring 22 for urging the clutch body 19 in a direction of releasing the engagement between the clutch pawls 20 and 21 is provided on the outer peripheral portion of the input shaft 8, and the clutch pawls 20 and 21 are further provided.
A shifter fork 23 for forcibly sliding the clutch body 19 in a direction in which the clutch bodies 19 are engaged with each other is provided. In addition,
The shifter fork 23 is connected to a shifter shaft 24 provided through the transmission case 5, and a lever 25 is connected to one end of the shifter shaft 24 protruding outside the transmission case 5, and this lever 25 Solenoid 27 via link mechanism 26
Are linked to.

Then, on the outer peripheral portion of the output shaft 11, the high speed side transmission gear is provided.
A high-speed side passive gear 28 that is a second passive gear meshing with 17 is rotatably fitted on the outside, and a boss portion 29 of this high-speed side passive gear 28
A low speed side passive gear 30, which is a first passive gear meshing with the low speed side transmission gear 18, is rotatably fitted on the outer circumference of the low speed side transmission gear 18, and a passive gear clutch claw 31 is radially provided on one side of the low speed side passive gear 30. Is formed in. A clutch pawl 33 is slidably spline-fitted to a spline portion 32 formed on the output shaft 11, and the clutch pawl 33 engages with the passive gear clutch pawl 31 in a disengageable manner.
A spring 35 for urging the clutch pawl body 33 in a direction in which the clutch pawl 34 and the passive gear clutch pawl 31 engage with each other is provided on the outer peripheral portion of the output shaft 11.

A spline portion 36 is formed on the outer periphery of the tip side of the boss portion 29, and a cam claw body 37 is slidably spline-fitted to the spline portion 36. On one side of the cam pawl 37 facing the low-speed side passive gear 30, a cam pawl 38 that is disengageably engaged with the passive gear clutch pawl 31 is formed, and the cam pawl 38 is provided on the top side. An inclined portion 39 having a narrower width is formed toward the low-speed side passive gear 30.
The top end surface of the cam pawl 38 extending to the side is set to be slightly closer to the passive gear clutch pawl 31 side than the top end surface of the clutch pawl 34 extending to the low-speed side passive gear 30 side. Has been done.

Further, a convex portion 40 is formed on the outer peripheral portion of the cam pawl body 37, and the convex portion 40 is inserted into the groove portion of the clutch pawl 34. Further, the clutch pawl 33 and the cam pawl 37
An urging body 41 is interposed between the urging body 41 and the urging body 41.
Biases the cam pawl body 37 in a direction in which the top of the cam pawl 38 and the top of the clutch pawl 34 are rotated in the direction in which they overlap.

Here, as shown in FIG. 1 and FIG. 6A, the clutch claw 34 and the cam claw 38 mesh with the passive gear clutch claw 31, and the low speed side passive gear 30, the clutch claw 33, and the cam claw 38 are engaged. body
In the state in which 37 is rotating integrally, as shown in FIGS. 6 (a) and 7 (a), there is a rotation direction angle “A” between the convex portion 40 and the clutch pawl 34. The gap is provided. Further, as shown in FIGS. 2 and 6 (c) and (d), the clutch pawls 20 and 21 are engaged with each other, and the engagement of the clutch pawl 34 and the cam pawl 38 with the passive gear clutch pawl 31 is released. Later, FIG. 6 (c),
As shown in (d) and FIGS. 7 (c) and (d), the convex portion 40 abuts on the side surface of the groove portion of the clutch pawl 34. At this time, the clearance "B" is formed so that the rotation direction angle "B" formed continuously by the top of the clutch claw 34 and the top of the cam claw 38 is larger than the rotation direction angle "C" of the groove of the passive gear clutch claw 31. A "is set.

In such a configuration, the rotation of the front wheel power output shaft 13 is
It is transmitted to the input shaft 8 via the joint 14. Here, as shown in FIG. 1, the clutch body is driven by the urging force of the spring 22.
In the state where 19 is slid and the engagement between the clutch pawls 20 and 21 is released, only the low speed side transmission gear 18 rotates integrally with the input shaft 8, and the rotation of the input shaft 8 is the low speed side transmission gear. 18, low speed side passive gear 30, passive gear clutch claw 3
1, transmitted to the output shaft 11 via the clutch pawl 34 and the clutch pawl body 33, and further transmitted to the front wheel power transmission shaft 16 via the joint 15. Then, the front wheels 42 of the tractor 1 are rotationally driven at a low speed by the rotation of the front wheel power transmission shaft 16.

Next, when the shift change operation for operating the solenoid 27 is performed, the clutch body 19 slides against the biasing force of the spring 22 via the link mechanism 26, the lever 25, the shifter shaft 24, and the shifter fork 23, and the second Clutch pawl 2 as shown
0,21 mesh with each other. Then, the rotation of the input shaft 8 is transmitted to the cam pawl body 37 via the clutch body 19, the clutch pawls 20, 21, the high speed side transmission gear 17, and the high speed side passive gear 28, and the cam pawl body 37
37 rotates integrally with the high speed side passive gear 28. On the other hand, the rotation of the input shaft 8 is continuously transmitted to the low-speed side passive gear 30 via the low-speed side transmission gear 18, and the cam claw body 37 is integrated with the low-speed side passive gear 30. The force that tries to rotate acts. Here, the rotational speed of the cam pawl 37 due to the power transmission from the high speed side passive gear 28 becomes higher than the rotational speed of the low speed side passive gear 30, and the passive gear clutch pawl 31 and the cam pawl 38
And a difference in the number of rotations occurs. For this reason, the passive gear clutch pawl 31 is moved to the inclined portion 39 of the cam pawl 38 due to the difference in the number of revolutions.
, The cam claw 38 rides on the passive gear clutch claw 31, and the cam claw body 37 receives a force in a direction of moving away from the low-speed side passive gear 30, and as shown in FIG.
37 slides in a direction to release the engagement between the cam claw 38 and the passive gear clutch claw 31. At the same time, the clutch pawl 33 pushed by the cam pawl 37 also slides integrally against the urging force of the spring 35, and the clutch pawl 34 and the passive gear clutch pawl are
The engagement with 31 is released.

Clutch pawl 34 and cam pawl 38 for passive gear clutch pawl 31
After the engagement with is released, the cam claw 37 that rotates integrally with the high-speed side passive gear 28 rotates in the rotation direction angle “A”.
After rotating only in the direction of the arrow "D", Fig. 6 (c), (d)
Also, as shown in FIGS. 7 (c) and 7 (d), the convex portion 40 abuts on the groove side surface of the clutch pawl 34. This allows the cam claw body 37
The clutch pawl 33 driven to rotate integrally with the cam pawl 37, and the rotation of the high-speed side passive gear 28 is transmitted to the output shaft 11 via the cam pawl 37 and the clutch pawl 33. ,
Further, it is transmitted to the front wheel power transmission shaft 16 via the joint 15. Then, the tractor 1 is rotated by the rotation of the front wheel power transmission shaft 16.
The front wheels 42 are driven to rotate at a high speed.

Further, when the convex portion 40 is in contact with the groove side surface of the clutch pawl 34, as shown in FIGS. 6 (c) and (d) and FIGS. 7 (c) and (d), the clutch pawl 34 The rotation direction angle "B" formed by the top and the top of the cam pawl 38 in succession is larger than the rotation direction angle "C" of the groove portion of the passive gear clutch pawl 31. Therefore, at least one of the top of the clutch pawl 34 and the top of the cam pawl 38 is always kept in contact with the top of the passive gear clutch pawl 31. Therefore, even if the clutch pawl 33 and the cam pawl 37 are biased toward the low-speed side passive gear 30 by the spring 35, the clutch pawl 34
The engagement and disengagement of the cam claw 38 with the passive gear clutch claw 31 is prevented, and noise and wear due to repeated engagement and disengagement are prevented.

When the solenoid 27 is deactivated, the shifter fork 23
The clutch body 19 is released from being pressed, and the clutch body 19 slides due to the urging force of the spring 22 and the clutch pawl 2
The meshing between 0 and 21 is released, and the transmission of the driving force from the high speed side transmission gear 17 to the high speed side passive gear 28 is cut off. Therefore, the abutting force of the convex portion 40 on the groove side surface of the clutch pawl 34 disappears, and the passive gear clutch pawl 31 is slightly raised so as to have a clearance “E” with the top of the clutch pawl 34.
By pushing the inclined portion 39 of the above, as shown in FIG. 7 (e), the angle in the direction of rotation continuously formed by the top of the cam pawl 38 and the top of the clutch pawl 34 is gradually reduced, and the passive gear clutch pawl 31 is rotated. When the groove angle becomes smaller than the rotational direction angle “C”, as shown in FIG. 7 (f), the cam pawl 38 and the clutch pawl 34 are moved by the biasing force of the spring 35 so that the passive gear clutch pawl is formed.
Mesh with 31.

When the top of the cam pawl 38 and the top of the passive gear clutch pawl 31 are in contact with each other, the friction of the contact surface and the urging force of the urging body 41 cause the top of the cam pawl 38 and the clutch to move. nail
The rotation direction angle formed continuously with the top of 34 gradually becomes smaller, and the rotation direction angle “C” of the groove portion of the passive gear clutch pawl 31 becomes smaller.
When the spring 35 becomes smaller and is aligned with the groove of the passive gear clutch pawl 31 as shown in FIG.
The cam claw 38 and the clutch claw 34 mesh with the passive gear clutch claw 31 by the urging force of. As a result, the rotation of the input shaft 8 is transmitted through the low-speed side passive gear 30 and the clutch pawl 33 to the output shaft 11
The front wheel power transmission shaft 16 is driven via the joint 15, and the front wheels 42 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 17 and the high-speed side passive gear 28 have a gear train. By replacing the gear trains of the low-speed side transmission gear 18 and the low-speed side passive gear 30 with each other,
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.

Further, FIG. 8 is a development view showing a meshing state of the clutch portion in which the shape of the cam pawl 38 is changed. Since the inclined portion 39 formed on the cam pawl 38 is formed only on one side, rotation in only one direction is high.
Although the low speed switching cannot be performed, the same effect as described above can be obtained.

As described above, the present invention releases the meshing between the cam claw and the clutch claw with the passive gear clutch claw, and brings the convex portion into contact with the groove side surface of the clutch claw so that the second passive gear moves from the cam claw body. When the power is transmitted to the driven shaft via the clutch pawl and the clutch pawl, the rotation direction angle formed by the cam claw top and the clutch claw top continuously is larger than the rotation direction angle of the groove portion of the passive gear clutch pawl. By setting it, it is possible to prevent the cam claw and the clutch claw from repeatedly engaging and disengaging with the passive gear clutch claw at the time of this power transmission, and the inclined part of the cam claw that becomes narrower toward the top side. And the top end surface of the cam pawl is located closer to the passive gear clutch pawl side than the top end surface of the clutch pawl, the gear shifting is performed to stop the rotational drive of the second passive gear. In this case, the passive gear clutch pawl comes into contact with a portion of the inclined portion of the cam pawl which is higher than the clutch pawl, whereby the cam pawl body is rotated in a direction in which the top portion of the cam pawl and the top portion of the cam pawl body are overlapped with each other. Therefore, the rotation direction angle formed by the top of the cam pawl and the top of the clutch pawl can be quickly reduced, and the cam pawl and the clutch pawl can be quickly engaged with the passive gear clutch pawl. Therefore, it is possible to smoothly transmit power from the first passive gear to the driven shaft based on the shift change that stops the rotational drive of the second passive gear, and further, the top of the cam pawl and the top of the clutch pawl are Based on the gear shift switching in which the rotational drive of the second passive gear is stopped by interposing an urging body for urging the cam claw body in the direction in which the two rotate in the overlapping direction between the cam claw body and the clutch claw body. Cam claw and ku It is possible to more quickly engage the passive gear clutch claw with the catch claw, and further downsize and reduce the cost as compared to a hydraulic multi-plate clutch or a speed change device using a synchromesh. It has the effect of being able to.

[Brief description of drawings]

1 to 7 show an 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 is a high speed side passive gear. FIG. 3 is a bottom view showing a power transmission state through a cross section, FIG. 3 is an enlarged perspective view showing an urging body, FIG. 4 is a side view showing a transmission case mounting state, and FIG. A side view showing the sixth
FIG. 7 is a front view showing a meshed state of the clutch portion, FIG. 7 is a developed view showing a meshed state of the clutch portion, and FIG. 8 is a developed view showing a meshed state of the clutch portion in a modified example. 11 …… driven shaft, 28 …… second passive gear, 30 …… first passive gear, 31 …… passive gear clutch pawl, 33 …… clutch pawl,
34 …… Clutch claw, 37 …… Cam claw body, 38 …… Cam claw, 39
...... Inclined part, 40 ...... Convex part, 41 ...... Biasing body

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. A protrusion that is fitted and is inserted into the groove portion of the clutch pawl is provided on the outer peripheral portion of the cam pawl body, and the top portion of the cam pawl and the clutch in a state where the convex portion abuts the groove portion side surface of the clutch pawl. The rotation direction angle formed continuously with the claw top is set to be larger than the rotation direction angle of the groove portion of the passive gear clutch claw, and the cam claw is formed with an inclined portion whose width becomes narrower toward the top side and the cam is formed. A gear shift device characterized in that a top end surface of a pawl is located closer to the passive gear clutch pawl side than a top end surface of the clutch pawl. 2. An urging member for urging the cam pawl body in a direction in which the top of the cam pawl and the top of the clutch pawl are rotated is interposed between the cam pawl and the clutch pawl. The shift change device according to claim 1, wherein: