JPH04145248A - Shift selector - Google Patents

Abstract

PURPOSE:To smooth the intermission of power transmission by making an angle being made up of two claw tops larger than that of a passive gear clutch claw groove part at time of contact between a cam claw and a clutch claw, forming a ramp to be narrowed toward a cam claw top part, and making up a tip surface of the cam claw to be higher than that of the clutch claw. CONSTITUTION:When engagement between a cam claw 38, a clutch claw 34 and a passive gear clutch claw 31 is released, a projection 40 is made contact with a groove part side of the clutch claw 34, and power transmission to a driven shaft 11 from a second passive gear 28 via a cam claw body 37 and a clutch claw body 33, an angle made up of both top parts of the cam claw 38 and the clutch claw 34 is made larger than that of a groove part of the passive gear clutch claw 31, through which such a possibility that the cam claw 38 and the clutch claw 34 might repeat their detachment with the passive gear clutch claw 31 is preventable at time of power transmission. In addition, a ramp 39, narrowing toward the top part side, is formed in the cam claw 38, and a top part tip surface of the cam claw 38 is made higher than that of the clutch claw 34, through which power transmission from a first passive gear 30 to the driven shaft 11 is smoothly performable at time of shift selecting of drive suspension of the second passive gear 28.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transmission switching device suitable for a transmission mechanism for driving a vehicle.

BACKGROUND OF THE INVENTION Conventionally, a plurality 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 selectively engaged with the driven shaft. In a speed change device that obtains rotational transmission using a speed change ratio, a sliding gear, a dock clutch, a synchromesh, a hydraulic multi-plate clutch, etc. are used as selective coupling means.

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

Problems to be Solved by the Invention However, it is not easy to separate the driving-side pawl and the driven-side pawl of the dock clutch from the rotational transmission state of the driving force. There must be. For this reason, when the dock clutch is used as a speed change switching device for a vehicle, a speed change switching operation cannot be performed unless the vehicle is once stopped.

On the other hand, when a hydraulic multi-plate clutch is used, power transmission can be smoothly interrupted and interrupted, but the disadvantage is that the speed change device becomes larger and the cost increases.

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 rotation speed different from that of the first passive gear based on a speed change operation are rotatably mounted on a driven shaft. A passive gear clutch pawl is formed radially on the side surface of the first passive gear, and a cam pawl that engages with the passive gear clutch pawl in a detachable manner is formed and integrally formed with the second passive gear. A rotating cam pawl body is provided so as to be slidable in a direction in which the cam pawl and the passive gear clutch pawl are engaged and disengaged, and the clutch pawl that engages with the passive gear clutch pawl in a freely engaging and disengageable manner is provided. A clutch pawl body is slidably spline-fitted onto the driven shaft so as to bias the cam pawl body in a direction in which the cam pawl engages with the gear clutch pawl and in a direction in which the cam pawl engages with the passive gear clutch pawl. , a convex portion inserted into the groove of the clutch pawl is provided on the outer periphery of the cam pawl body, and the top of the cam pawl and the top of the clutch pawl when the convex portion is in contact with a side surface of the groove of the clutch pawl. and the angle formed by the grooves of the passive gear clutch pawl is set to be larger than the 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 side, and the top end surface of the cam pawl is It is formed higher than the top end surface of the clutch pawl.

Further, a biasing body is interposed between the cam pawl and the clutch pawl for urging the cam pawl to rotate in a direction in which the top of the cam pawl and the top of the clutch pawl overlap.

Operation In a normal power transmission state, only the first passive gear is rotationally driven, and the clutch pawl body is integrated with the first passive gear due to the engagement between the passive gear clutch pawl of the first passive gear and the clutch pawl of the clutch pawl body. The driven shaft, to which the clutch pawl is spline-fitted, is driven to rotate. The cam pawl of the cam pawl body is engaged with the passive gear clutch pawl, and the cam pawl body and the second passive gear rotate integrally with the first passive gear.

When a speed change operation is performed to rotationally drive the second passive gear, the first passive gear continues to be rotationally driven, and the rotational speed of the second passive gear is different from that of the first passive gear. For this reason, there is a difference in the rotation speed of the cam pawl body, which 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 body rotates integrally with the first passive gear. The cam pawl body slides in a direction in which the cam pawl and the passive gear clutch pawl are disengaged by rotating relative to each other and the cam pawl rides on the passive gear clutch pawl.

As the cam pawl body slides, the clutch pawl body pushed by the cam pawl body also slides in a direction to release the engagement between the clutch pawl and the passive gear clutch pawl.

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 convex portion of the cam pawl body that rotates integrally with the second passive gear The cam pawl body and the clutch pawl body rotate integrally by coming into contact with the side surface of the groove portion of the clutch pawl. This results in
The driven shaft rotates integrally with the second driven gear, and the gear change is completed. At this time, since the continuous angle between the top of the cam pawl and the top of the clutch pawl is set larger than the angle of the groove of the passive gear clutch pawl, the top end surface of the cam pawl and the top end surface of the clutch pawl Either one of them comes into contact with the top end surface of the passive gear clutch pawl, and the cam pawl and the clutch pawl are prevented from repeatedly engaging and disengaging with the passive gear clutch pawl.

When a gear change operation is performed to cut off the transmission of driving force to the second passive gear, the contact force of the convex part of the clutch pawl against the side surface of the groove disappears, and the passive gear clutch pawl comes into contact with the inclined part of the cam pawl, causing the cam pawl to The cam pawl body rotated in the direction in which the top of the cam pawl and the top of the clutch pawl overlapped, and eventually the continuous angle between the top of the cam pawl and the top of the clutch pawl became smaller than the angle of the groove of the passive gear clutch pawl. At this time, the cam pawl and the clutch pawl mesh with the passive gear clutch pawl, and the driven shaft again rotates integrally with the first passive gear.

In addition, by interposing a biasing body that urges the cam pawl body in the direction where the top of the cam pawl and the top of the clutch pawl overlap, the cam pawl can be moved in the direction where the top of the cam pawl and the top of the clutch pawl overlap. The rotation of the body is promoted, and the engagement between the cam pawl and the clutch pawl with the passive gear clutch pawl is promoted, so that transmission of the driving force to the second passive gear is cut off, thereby speeding up the speed change. be exposed.

Example An embodiment of the present invention will be described based on the drawings.

A clutch case 2 and a transmission case 3 are provided in the abdomen of the tractor 1. Furthermore, the clutch case 2
A transmission case 5 is attached by bolts 4 below and in front of the transmission case 3. Inside the transmission case 5, there is an input shaft 8 that is supported by a bearing 6f7, and an output shaft that is a driven shaft that has an axis parallel to the input shaft 8 and is supported by bearings 9 and 10. 11 are stored. A front wheel power take-off shaft 13 supported by a bearing 12 in the transmission case 3 is connected to the tip of the input shaft 8 via a cylindrical joint 14.
Further, a front wheel power transmission shaft 16 is connected to the distal end of the output shaft 11 via a cylindrical joint 15.

A high-speed transmission gear 17 is rotatably fitted onto the outer periphery of the input shaft 8, and a low-speed transmission gear 18 is spline-fitted thereto. Further, a clutch body 19 is slidably spline-fitted to the outer peripheral portion of the input shaft 8 between the bearing 6 and the high-speed transmission gear 17, and a clutch pawl is fitted to the clutch body 19. 20 is formed, and a clutch pawl 21 is formed on the side surface of the high-speed side transmission gear 17 and engages with the clutch pawl 20 in a freely engageable and disengageable manner. A spring 22 is provided on the outer periphery of the input shaft 8 to bias the clutch body 19 in a direction in which the clutch pawls 20 and 21 are disengaged from each other, and the clutch pawls 20 and 21 are also engaged with each other. A shifter fork 23 is provided for forcibly sliding the clutch body 19 in this direction. 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 that protrudes outside the transmission case 5. The lever 25 is connected to a solenoid 27 via a link mechanism 26.

Next, a high-speed side passive gear 28, which is a second passive gear that meshes with the high-speed side transmission gear 17, is rotatably fitted onto the outer circumference of the output shaft 11, and a boss portion 29 of the high-speed side passive gear 28 is fitted onto the outer peripheral portion of the output shaft 11. A low-speed side passive gear 3o, which is a first passive gear that meshes with the low-speed side transmission gear 18, is rotatably fitted on the outer periphery, and a passive gear clutch pawl 31 is arranged radially on one side of the low-speed side passive gear 30. It is formed. Further, a clutch pawl body 33 is slidably spline-fitted into a spline portion 32 formed on the output shaft 11, and a clutch pawl 34 that engages with the passive gear clutch pawl 31 in a detachable manner is fitted to the clutch pawl body 33. A spring 35 is provided on the outer periphery of the output shaft 11 to bias the clutch pawl body 33 in the direction in which the clutch pawl 34 and the passive gear clutch pawl 31 engage with each other.

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 formed on this spline portion 36.
are fitted with splines so that they can slide freely. A cam pawl 38 that removably engages with the passive gear clutch pawl 31 is formed on one side of the cam pawl body 37 facing the low-speed side passive gear 30. A sloped portion 39 is formed whose width becomes narrower toward the surface, and further,
The top end surface of the cam pawl 38 extending toward the low speed driven gear 30 side is set slightly higher than the top end surface of the clutch pawl 34 extending toward the low speed driven gear 30 side.

Further, a convex portion 40 is formed on the outer peripheral portion of the cam pawl body 37, and this convex portion 40 is inserted into the groove portion of the clutch pawl 34. Furthermore, a biasing body 41 is interposed between the clutch pawl body 33 and the cam pawl body 37,
20 The biasing body 41 is connected to the top of the cam pawl 38 and the clutch pawl 34.
The cam claw body 3 rotates in a direction in which the top of the cam claw body 3 overlaps with the top of the
7 is energized.

Here, as shown in FIGS. 1 and 6(a), the clutch pawl 34 and the cam pawl 38 are connected to the passive gear clutch pawl 31.
are engaged with each other, and the low-speed side passive gear 30 and the clutch pawl body 33
When the cam pawl body 37 and the cam pawl body 37 are rotating together, there is an angle II between the convex portion 40 and the clutch pawl 34, as shown in FIGS. 6(a) and 7(a). A gap of A u is provided. In addition, Fig. 2 and Fig. 6 (c),
As shown in FIG. 6(d), after the clutch pawls 20 and 21 are engaged with each other and the engagement between the clutch pawl 34 and the cam pawl 38 with respect to the passive gear clutch pawl 31 is released, as shown in FIGS. ) and Figure 7(c)
, the convex portion 40 comes into contact with the side surface of the groove of the clutch pawl 34, as shown in (d). At this time, the angle ii B n continuously formed by the top of the clutch pawl 34 and the top of the cam pawl 38 is
The gap angle "A" is set to be larger than the angle of the groove of the passive gear clutch pawl 3 +iCn.

In such a configuration, the rotation of the front wheel power take-off shaft 13 is transmitted to the input shaft 8 via the joint 14. Here, as shown in FIG. 1, when the clutch body 19 is slid by the biasing force of the spring 22 and the clutch pawls 20 and 21 are disengaged, only the low-speed transmission gear 18 is connected to the input shaft 8. The rotation of the input shaft 8 is transmitted to the output shaft 11 via the low-speed transmission gear 18, the low-speed passive gear 30, the passive gear clutch pawl 31, the clutch pawl 34, and the clutch pawl body 33, Furthermore, the joint 15
The power is transmitted to the front wheel power transmission shaft 16 via. The rotation of the front wheel power transmission shaft 16 rotates the front wheels 42 of the tiger geter 1 at a low speed.

Next, when a gear change operation is performed to activate the solenoid 27, the clutch body 19 is slid against the urging force of the spring 22 via the link mechanism 26, lever 25, shifter shaft 24, and shifter fork 23, and the second As shown in the figure, the clutch pawls 20 and 21 engage with each other. Then, the rotation of the input shaft 8 is caused by the clutch body 19, clutch pawls 20, 21.
, the high-speed side transmission gear 17 and the high-speed side passive gear 28 to the cam pawl body 37, and the cam pawl body 37 rotates integrally with the high-speed side passive gear 28. On the other hand, the input shaft 8 continues to rotate via the low-speed transmission gear 18 to the low-speed passive gear 30.
This cam claw body 37 is transmitted to the cam claw body 37.
A force acts to cause the gear to rotate integrally with the low-speed side passive gear 30. Here, the rotational speed of the cam pawl body 37 due to 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 there is a difference in the rotational speed between the passive gear clutch pawl 31 and the cam pawl 38. occurs. Therefore, due to this difference in rotational speed, the passive gear clutch pawl 31 comes into contact with the inclined part 39 of the cam pawl 38, and the cam pawl 38 rides on the passive gear clutch pawl 31, and the cam pawl body 37 separates from the low speed side passive gear 3o. As shown in FIG. 7(b), the cam pawl body 37 slides in the direction in which the cam pawl 38 and the passive gear clutch pawl 31 are disengaged.

At the same time, the clutch pawl body 33 pushed by the cam pawl body 37 also slides together against the urging force of the spring 35, and the engagement between the clutch pawl 34 and the passive gear clutch pawl 31 is released.

After the clutch pawl 34 and cam pawl 38 are disengaged from the passive gear clutch pawl 31, the cam pawl body 37, which rotates integrally with the high-speed side passive gear 28, rotates at an angle I.
After rotating in the direction of arrow "D" by I A I+, the 6th
As shown in Figures (c) and (d) and Figures 7 (C) and (()), the convex portion 40 comes into contact with the side surface of the groove portion of the clutch pawl 34.

As a result, the clutch pawl body 3 driven by the cam pawl body 37
3 rotates integrally with the cam pawl body 37, and the rotation of the high-speed side passive gear 28 is transmitted to the output shaft 11 via the cam pawl body 37 and the clutch pawl body 33.
5 to the front wheel power transmission shaft 16. and,
The front wheels 42 of the tractor 1 are rotated by the rotation of the front wheel power transmission shaft 16.
is rotated at high speed.

Further, when the convex portion 40 is in contact with the side surface of the groove of the clutch pawl 34, FIGS. 6(C), (d) and 7(
As shown in c) and (d), the angle "B" formed by the top of the clutch pawl 34 and the top of the cam pawl 38 is larger than the angle "CI+" of the groove 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 maintained in contact with the top of the passive gear clutch pawl 31. Therefore, the clutch pawl body 33 and the cam pawl body 37 are kept in contact with the top of the passive gear clutch pawl 31. Even if the spring 35 urges the low-speed side passive gear 30, the clutch pawl 34 and cam pawl 38 are prevented from repeatedly engaging and disengaging from the passive gear clutch pawl 31, thereby reducing noise and wear due to repeated engagement and disengagement. occurrence is prevented.

When the operation of the solenoid 27 is stopped, the pressure on the clutch body 19 by the shifter fork 23 is released, and the clutch body 19 slides by the biasing force of the spring 22, and the engagement between the clutch pawls 20 and 21 is released, and the high-speed side transmission Drive force transmission from gear 17 to high-speed side passive gear 28 is cut off. Therefore, the abutting force of the convex portion 40 on the side surface of the groove of the clutch pawl 34 is eliminated, and the passive gear clutch pawl 31 is a slightly raised cam pawl with a gap "'E" from the top of the clutch pawl 34. As shown in FIG. 7(e), the angle between the top of the cam pawl 38 and the top of the clutch pawl 34 becomes gradually smaller. Groove angle “′
C'', as shown in FIG. 7(f), the cam pawl 38 and clutch pawl 34 engage with the passive gear clutch pawl 31 due to the biasing force of the spring 35.

In addition, 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 frictional force of the abutting surfaces and the urging force of the urging body 41 cause the top of the cam pawl 38 and the clutch The angle formed by the top of the pawl 34 becomes gradually smaller, and the angle of the groove of the passive gear clutch pawl 31 becomes "CI+".
The cam pawl 38 and the clutch pawl 34 engage with the passive gear clutch pawl 31 due to the urging force of the spring 35 when the cam pawl 38 and the clutch pawl 34 become smaller and meet the groove of the passive gear clutch pawl 31 as shown in FIG. 7(f). As a result, the rotation of the input shaft 8 is transmitted to the output shaft 11 via the low speed side passive gear 30 and the clutch pawl body 33, the front wheel power transmission shaft 16 is driven via the joint 15, and the front wheel 42 is driven via the joint 15. is rotated again at low speed.

In this embodiment, the low-speed transmission state is normally set, and the low-speed power transmission is temporarily cut off only during high-speed transmission, but the gear train of the high-speed transmission gear 17 and the high-speed passive gear 28 By changing the gear train of the low-speed side transmission gear 18 and the low-speed side passive gear 30, it is possible to maintain a high-speed transmission state in normal times and also temporarily cut off high-speed side power transmission only during low-speed transmission. good.

Moreover, FIG. 8 is a developed view showing the engaged state of the clutch part in which the shape of the cam pawl 38 is changed, and since the inclined part 39 formed on the cam pawl 38 is formed only on one side, rotation can only occur in one direction at high or low speeds. However, the same effect as described above can be obtained.

Effects of the Invention As described above, the present invention disengages the cam pawl and the clutch pawl from the passive gear clutch pawl, and also brings the convex portion into contact with the side surface of the groove of the clutch pawl, thereby removing the cam pawl body from the second passive gear. By setting the continuous angle between the top of the cam pawl and the top of the clutch pawl to be larger than the angle of the groove of the passive gear clutch pawl when power is transmitted to the driven shaft through the clutch pawl body and the clutch pawl body. During this power transmission, it is possible to prevent the cam pawl and clutch pawl from repeatedly engaging and disengaging with the passive gear clutch pawl, and also by forming an inclined part on the cam pawl that becomes narrower toward the top side. By forming the top end surface of the cam pawl higher than the top end surface of the clutch pawl, when a gear change is made to stop the rotational drive of the second passive gear, the slope of the cam pawl becomes higher than the clutch pawl. When the passive gear clutch pawl comes into contact with this part, the cam pawl body is rotated in the direction where the top of the cam pawl and the top of the cam pawl body overlap, so that the top of the cam pawl and the top of the clutch pawl are continuous. The angle formed by the clutch can be quickly reduced, and the cam pawl and 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 speed change that stops the rotational drive of the second passive gear, and furthermore, in the direction in which the top of the cam pawl and the top of the clutch pawl overlap. By interposing a biasing body between the cam pawl body and the clutch pawl body, which urges the cam pawl body in the direction of rotation, the cam pawl based on the speed change that stops the rotational drive of the second passive gear. To enable the clutch pawl to engage the passive gear clutch pawl more quickly, and to achieve smaller size and cost reduction compared to a speed change device using a hydraulic multi-plate clutch or a synchromesh. It has effects such as being able to.

[Brief explanation of drawings]

Figures 1 to 7 show an embodiment of the present invention. Figure 1 is a bottom view showing a cross section of the state of power transmission via the low-speed passive gear, and Figure 2 is a bottom view showing the state of power transmission through the low-speed passive gear. Fig. 3 is a perspective view showing an enlarged view of the biasing body, Fig. 4 is a side view showing the installation state of the transmission case, and Fig. 5 is the entire tractor. 6th side view showing
7 is a developed view showing the engaged state of the clutch portion, and FIG. 8 is a developed view showing the engaged 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 body, 34...Clutch pawl, 37...
・Cam claw body, 38...Cam claw, 39...Slope part, 4
o...Protrusion, 41...Biasing body Applicant Ishikawajima Shibaura Machinery Co., Ltd. (a) J Figure 7 (b) (C) (+) (a) (cl) Figure 0 (b) (e ) (C) (+)

Claims (1)

[Scope of Claims] 1. A first passive gear that is constantly rotationally driven and a second passive gear that is rotationally driven at a rotation speed different from that of the first passive gear based on a speed change operation are rotatable on a driven shaft. A passive gear clutch pawl is formed radially on the side surface of the first passive gear, and a cam pawl is formed that engages with the passive gear clutch pawl in a freely engaging and disengageable manner, and is integral with the second passive gear. A cam pawl body that rotates is provided to be slidable in a direction in which the cam pawl and the passive gear clutch pawl engage and disengage, and a clutch pawl that engages with the passive gear clutch pawl in a freely engaging and disengageable manner is provided, and the clutch pawl and the A clutch pawl body that is biased in a direction in which the cam pawl engages with the passive gear clutch pawl and urges the cam pawl body in a direction in which the cam pawl engages with the passive gear clutch pawl is slidably spline-fitted onto the driven shaft. A convex portion inserted into the groove of the clutch pawl is provided on the outer periphery of the cam pawl body, and when the convex portion is in contact with a side surface of the groove of the clutch pawl, the top of the cam pawl and the clutch pawl are connected to each other. The continuous angle with the top part is set to be larger than the angle of the groove of the passive gear clutch pawl, and the cam pawl is formed with an inclined part whose width becomes narrower toward the top side, and the tip end surface of the top part of the cam pawl is A speed change switching device characterized in that the clutch pawl is formed higher than the top end surface thereof. 2. A biasing body is interposed between the cam pawl body and the clutch pawl body for urging the cam pawl body to rotate in a direction in which the top of the cam pawl and the top of the clutch pawl overlap. The speed change switching device according to claim 1.