JPH05302673A - Speed change operation mechanism for axle driving device - Google Patents

Abstract

PURPOSE:To constitute a shock absorber at a low cost by arranging a cylinder case part of the shock absorber integrally on the inner wall of an axle case and boring orifice holes in a piston connected to a speed change arm so that oil in the axle case can be flowed freely. CONSTITUTION:A cylinder case 9 of a shock absorber is arranged in a hole bored in an inner thick wall part of a lower axle case 2, and a piston 8 is fitted inside of it so as to be slidable freely, and a block cover 21 is embedded in/fixed to the upper part of the cylinder case 9. An oil passage 13 and orifice holes 11 and 12 are bored in a piston rod 7 and the piston 8 in a condition of being communicated with each other so that oil in an axle case composed of an upper axle case 1 and the lower axle case 2 can flow into/flow out from two chambers partitioned by means of the cylinder case 9 and the piston 8. In such a constitution, since the cylinder case 9 can be processed simultaneously when the axle cases 1 and 2 are manufactured, an exclusive part or a fixing jig for the cylinder case 9 can be obviated. Thereby, the assembling manhours can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear shift operation mechanism for an axle drive device capable of driving an axle in a continuously variable vehicle in a continuously variable manner.

[0002]

2. Description of the Related Art Conventionally, in an axle drive device, a shock absorber that slows down the shifting operation of a hydraulic continuously variable transmission that inputs engine power and outputs power after shifting to an axle is provided inside an axle case. The technique of arranging in is known. For example, it is like the technique described in Japanese Utility Model Laid-Open No. 3-69755.

[0003]

However, in the above-mentioned prior art, the cylinder case of the shock absorber is
It was a dedicated part that was placed inside the axle case. In addition, the cylinder case is immovably fixed in the axle case by using a dedicated fixing tool, resulting in a large number of assembly steps. Because of these configurations, it was constructed as an expensive shock absorber. The present invention solves this problem and configures the shock absorber at a low cost.

Further, in this type, during the shifting operation of the hydraulic continuously variable transmission, the operating force against the neutral biasing spring device for automatically returning from the shift position to the neutral position and the shock absorber as damping resistance. There is a problem in that the operation becomes heavy because it requires a double operation force of expanding and contracting against it. A second object of the present invention is to improve the shock absorber to reduce the shift operation force.

[0005]

The problems to be solved by the present invention are as described above, and the means for solving the problems will be described below. That is, a shock absorber that slows down the shifting operation of a hydraulic continuously variable transmission that inputs engine power and outputs shifting power to an axle is arranged inside an axle case that is a sump, and the shock absorber The cylinder case is integrally provided on the inner wall of the axle case, and the piston connected to the speed change arm of the hydraulic continuously variable transmission is slidably fitted in the cylinder case. The throttle hole is provided to allow the oil in the axle case to flow freely.

Further, the present invention is provided with a neutral urging spring device which operates so as to return to a neutral position when the hydraulic continuously variable transmission is not operated, and the shock absorber is provided only when the neutral urging spring device is activated. Is configured to function.

[0007]

[Operation] Next, the operation will be described. By operating the shift lever or shift pedal, the shift operation arm 3 is rotated via a link or a wire. The movable swash plate 6 is rotated by the rotation of the speed change operation arm 3 via the speed change operation shaft 4 and the internal arm 5. The piston rod 7 and the piston 8 pivotally supported at the other end of the internal arm 5 are used. The movement of the movable swash plate 6 is slowed by the shock absorber mechanism, so that the rotation speed of the movable swash plate 6 is also slowed. That is, according to claim 1 of the present invention, when the piston 8 moves up and down inside the cylinder case 9, the oil flowing between the piston 8 and the cylinder case 9 loses its destination and the throttle holes 11, 12, 13 are lost. Therefore, the piston 8 is gradually returned to the axle case, and the vertical movement of the piston 8 must be slow. The slow movement of the piston 8 slows the movement of the inner arm 5 and the movable swash plate 6.

According to the second aspect of the present invention, the operation force of the hydraulic continuously variable transmission at the time of shifting operation is only the operation force against the neutral biasing spring device, and the shock absorber follows it. And since it only expands and contracts freely, the gear shifting operation is lighter than conventional ones. When the gear shifting operation is stopped, the neutral bias spring device operates and the hydraulic continuously variable transmission tries to return to the neutral position.At that time, the shock absorber functions and the return speed to the neutral position is the damping resistance of the shock absorber. The shock caused by stopping the vehicle is reduced.

[0009]

EXAMPLES Next, examples will be described. FIG. 1 is a plan view of an axle drive device of the present invention with an upper axle case 1 removed, and FIG. 2 is a side view I-I cross-sectional view of a hydraulic pump portion arranged on a hydraulic pump mounting surface of a manifold 10.
4 is a front sectional view taken along the line KK of the shift operating mechanism and the shock absorber according to the first embodiment of the present invention, and FIG. 4 is a lower axle case 2
Cylinder case 9 and piston 8 bored on the inner wall of the
5 is a perspective view of an operating mechanism and a shock absorber according to a second embodiment of the present invention, and FIG.
It is a sectional view of the HH part concerning.

Referring to FIG. 1, the overall construction of the axle drive device will be described. The axle drive device constitutes an axle case by joining an upper axle case 1 and a lower axle case 2 which are upper and lower half cases. The left and right axles 22, 22, the counter shaft 26, and the output shaft 24 are supported on the joint surface between the upper axle case 1 and the lower axle case 2 via a bearing device. In addition, it is a joint surface between the upper axle case 1 and the lower axle case 2, and the upper axle case 1
The manifold 10 is fixed to the side by bolts from below.

The manifold 10 is formed in an "L" shape in a front sectional view, the upper surface of the "L" shape constitutes a hydraulic pump mounting surface, and the side surface constitutes a hydraulic motor mounting surface. The input shaft 14 of the axle drive device constitutes a shaft for driving the hydraulic pump P, and the output shaft 24 constitutes a shaft integrated with the hydraulic motor M. The rotation of the output shaft 24 is decelerated and transmitted to the counter shaft 26 by a gear, and then decelerated and transmitted from the counter shaft 26 to the differential gear device 25. The differential rotation generated by the differential gear device 25 is configured to be transmitted to the left and right axles 22,22.

As shown in FIG. 2, a cylinder block 15 is installed on the surface of the manifold 10 on which the hydraulic pump is mounted, and the pump piston 20 is movable back and forth in a plurality of cylinder holes.
Is brought into contact with the thrust bearing 18 of the movable swash plate 6. The back portion of the movable swash plate 6 is formed in an arc shape in cross section, and is tiltably guided and held along the inner wall of the upper axle case. The angle of the movable swash plate 6 is changed by the rotation of the speed change operation arm 3. That is, the gear shift operation arm 3 is connected to the gear shift operation shaft 4 and the inner arm 5, and the roller pivot shaft 28 is fixed to the tip of the inner arm 5. A roller 27 is loosely fitted to the roller pivot shaft 28, and the roller 27 is fitted in the engaging groove 6 a of the movable swash plate 6. The gear shift operation shaft is constantly biased by a neutral biasing spring so that the movable swash plate 6 is at the neutral position.

A filter 16 is interposed between the lower surface of the manifold 10 and the inner wall of the bottom surface of the lower axle case 2. Inside the manifold 10, a pair of check valves (not shown) are provided in an oil passage (not shown) that connects the hydraulic pump P and the hydraulic motor M. The axle case is configured as an oil sump, and the oil is stored in the hydraulic pump P.
When the pressure oil circulating between the hydraulic motor M and the hydraulic motor M is insufficient, the pressure oil is purified by the filter 16 and the check valve is opened to replenish the oil. Further, there is provided a bypass operation mechanism that opens the check valve by operating the opening operation rods 30 and 30 shown in FIG. 1 and releases pressure oil between the hydraulic pump P and the hydraulic motor M. Reference numeral 19 denotes a bypass operation arm. When the bypass operation arm 19 is rotated, the branch arm 29 is operated left and right by the eccentric operation shaft, and the opening operation rods 30 and 30 are pushed against the biasing springs.
The check valve is opened.

The cylinder case 9 of the shock absorber, which constitutes an essential part of the present invention, is formed in the thick wall portion of the inner wall of the lower axle case 2 in the portion surrounded by the bypass operation arm 19, the manifold 10 and the speed change operation shaft 4. It is provided in the provided hole. Next, referring to FIGS. 2, 3, and 4, the cylinder case 9, the piston 8, the oil passage 13, and the throttle hole 1
The configuration of 1 · 12 will be described.

The inner arm 5 is formed in a bifurcated shape, and the roller pivot shaft 28 is provided on one of them.
On the other hand, the upper end of the piston rod 7 is pivotally supported. A piston 8 is fixed to the lower end of the piston rod 7. A hole formed in an inner wall portion of the lower axle case 2 is a cylinder case 9 whose upper portion opens at a joint surface between the upper axle case 1 and the lower axle case 2, and a piston 8 is slidably inserted therein. A closing lid 21 that fits and closes the upper part of the cylinder case 9 is fitted and fixed. In that state,
The oil in the axle case formed by the upper axle case 1 and the lower axle case 2 flows into the piston rod 7 and the piston 8 so that the oil can flow into and out of the two chambers partitioned by the cylinder case 9 and the piston 8. The oil passage 13 and the throttle holes 11 and 12 are communicated with each other.

The throttle hole 11 opens on the lower surface of the piston 8,
The throttle hole 12 is opened in the upper chamber of the piston 8 inside the cylinder case 9, and the oil passage 13 is opened in the portion where the piston rod 7 is out of the cylinder case 9. Throttle hole 11.1
2 and the oil passage 13 communicate with each other. In this configuration, when the piston 8 moves up and down inside the cylinder case 9, the compressed oil between the piston 8 and the cylinder case 9 loses its destination and gradually comes out from the throttle hole 12 or 13 and the throttle hole 13 Alternatively, the oil in the axle case is sucked from 12 and the vertical movement of the piston 8 becomes slow.

According to the first embodiment of the present invention, when the gear shift operation arm 3 is automatically returned to the neutral position by the neutral biasing spring device S when the gear shift lever L is released to stop the vehicle,
The shock absorber functions, the return speed to the neutral position is slowed down by the shock absorber's damping resistance,
This is advantageous because the shock caused by stopping the vehicle is reduced, but during the gear shifting operation of the hydraulic continuously variable transmission, the operating force that opposes the neutral biasing spring device S and the shock absorber expands and contracts against the damping resistance. The operation becomes heavy because it requires a double operation force. Therefore, in the second embodiment of the present invention, the shift operation force is reduced by constructing the shock absorber as shown in FIG.

That is, the piston sleeve 30 is fitted into the hole formed in the inner wall of the lower axle case 2 so that the piston sleeve 30 cannot be pulled out at the joint surface of the upper axle case 1. The piston 8 slidably inserted into the piston sleeve 30 is formed with two annular grooves 33a and 33b.
Each of them is openable to the axle case through the check balls 32a and 32b provided inside the piston sleeve 30 and the slit groove 30a formed on the outer peripheral surface of the piston sleeve 30, and the piston 8 is pierced. The two oil chambers 34a and 34b are connected to two chambers partitioned by both end surfaces of the piston 8. The chambers are openable to the inside of the axle case through the oil passages 31a and 31b of the piston sleeve 30 and the slit groove 30a.

The piston 8 shown in FIG. 5 is placed in the neutral position. For example, when the hydraulic continuously variable transmission is operated to shift to the forward side against the neutral biasing spring device S, the piston 8 is pushed downward, but the oil filling the chamber on the compression side is restricted by the throttle hole. Oil passage 3 rather than being discharged through 11
The check ball 32a is opened from 4a through the annular groove 33a, and is discharged from the slit groove 30a to the axle case without any resistance. On the other hand, oil flows into the room on the expansion side from the slit groove 30a through the oil passage 31b. In this way, the gear shift operation force can be reduced because it does not function as a shock absorber during gear shift operation.

When the shifting operation is stopped, the hydraulic continuously variable transmission tries to return to the neutral position by the operation of the neutral urging spring device S. At that time, the outer peripheral surface of the piston 8 has the oil passage 31a.
Since the check ball 32a is closed, the chamber on the side where the piston 8 is pulled upward and expands becomes a negative pressure, and the oil gradually increases from here to the oil passage 13 through the throttle hole 11. It will be filled and function as a shock absorber. After that, the oil passage 31a is released from the closed state and returns to the neutral position shown in the drawing.

At the time of gear shift operation to the reverse side, the piston 8 is pulled upward from the state shown in the figure, but at this time, the oil in the compression side chamber is the same as the above, the check ball 32.
Since b is opened and released, there is no shock absorber function, and when it is pushed downward by the neutral spring device S when it is not operated, the chamber on the expansion side becomes negative pressure as in the above, and oil is discharged through the throttle hole 12. Since it is filled, it functions as a shock absorber.

If a shock absorber having a damping resistance value when functioning on the forward side of the vehicle and a damping resistance value when functioning on the reverse side of the vehicle is the same, a vehicle with different front and rear tire diameters and front and rear directions is used. If there is a deviation in the position of the center of gravity and there is a difference in vehicle speed setting between the forward drive side and the reverse drive side, for example, a shock may occur on the reverse drive side even though the vehicle stops on the forward drive side without a shock. In such a case, the damping diameters of the throttle holes 11 and 12 and the volumes of the two chambers partitioned by the piston 8 are relatively changed so that the damping resistance value on the forward side of the vehicle and the damping resistance value on the reverse side of the vehicle are adjusted. It can be made different.

[0023]

Since the present invention is configured as described above, it has the following effects. That is, according to the first aspect, when the axle case is manufactured, the portion of the cylinder case 9 can be processed at the same time. Also,
It is no longer necessary to arrange a dedicated part for the cylinder case inside the axle case. Further, since the cylinder case 9 is integrally formed with the axle case, it is not necessary to provide a dedicated fixing portion or fixing tool for fixing the cylinder case 9. As a result, the number of assembling steps can be reduced. For the above reasons, the shock absorber can be provided at low cost.

According to the second aspect of the present invention, the gear shifting operation force of the hydraulic continuously variable transmission requires only a force that resists the neutral biasing spring device S, and the shock absorber follows this and has no resistance. Since it only expands and contracts, it can make the gear shifting operation lighter than conventional ones. When the hydraulic continuously variable transmission is returned to the neutral position by stopping the gear shifting operation and operating the neutral biasing spring device, the shock absorber functions and the return speed to the neutral position is slowed down by the damping resistance of the shock absorber. The shock caused by stopping the vehicle is reduced.

[Brief description of drawings]

FIG. 1 is a plan view of an axle drive device of the present invention with an upper axle case 1 removed.

2 is a side (II in FIG. 1) cross-sectional view of a hydraulic pump portion arranged on a hydraulic pump mounting surface of a manifold 10. FIG.

FIG. 3 is a front (K-K in FIG. 1) cross-sectional view of the shift operation mechanism and the shock absorber according to the first embodiment of the present invention.

FIG. 4 is a perspective view of a cylinder case 9 and a piston 8 formed in an inner wall portion of a lower axle case 2.

FIG. 5 is a front sectional view of a gear shift operation mechanism and a shock absorber according to a second embodiment of the present invention.

6 is a cross-sectional view taken along line HH of FIG.

[Explanation of symbols]

 1 Upper Axle Case 2 Lower Axle Case 3 Shift Operating Arm 4 Shift Operating Shaft 5 Inner Arm 6 Movable Swash Plate 7 Piston Rod 8 Piston 9 Cylinder Case 10 Manifold 11, 12 Throttle Hole 13 Oil Path 14 Input Shaft

Claims (2)

[Claims] 1. A shock absorber for slowing down a shift operation of a hydraulic type continuously variable transmission for inputting engine power and outputting shift power to an axle, wherein the shock absorber is arranged inside an axle case as a sump. The cylinder case part of the shock absorber is integrally provided on the inner wall of the axle case, and the piston connected to the speed change arm of the hydraulic continuously variable transmission is
A gear shifting operation mechanism for an axle drive device, wherein the piston is slidably fitted in the cylinder case, and a throttle hole is formed in the cylinder case to allow oil in the axle case to flow freely. 2. A neutral urging spring device that operates to return to a neutral position when the hydraulic continuously variable transmission is not operated to shift, and the shock is provided only when the neutral urging spring device operates. A gear shift operation mechanism for an axle drive device, which is configured to function as an absorber.