JPH05187515A - Axle drive unit - Google Patents

Abstract

PURPOSE:To enlarge the range of the variable speed more than double compared to the conventional one and use a pump and a motor of one rank lower than the ordinary one by not only changing discharge capacitor of a hydraulic pump as conventional but making a swash plate of a hydraulic motor movable. CONSTITUTION:In this hydraulic type continuously variable transmission a hydraulic pump is rotated through rotation transmitted by an input shaft 5, pressure oil is fed to a hydraulic motor discharged from the hydraulic pump, and an output shaft 6 of the hydraulic motor is rotated. A pump movable swash plate 28 of the hydraulic pump is freely rotated by the first change gear operation arm 26, and a motor movable swash plate 34 of the hydraulic motor is freely rotated by the second change gear operation arm 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axle drive device in which a hydraulic continuously variable transmission constituted by a hydraulic pump and a hydraulic motor is arranged inside a casing.

[0002]

2. Description of the Related Art Conventionally, a technique relating to an axle drive device in which a hydraulic continuously variable transmission is arranged inside a casing and the rotation after shifting by the hydraulic continuously variable transmission is transmitted to an axle via a differential gear device. Is known. For example, US Pat. No. 4,932,209 or US Pat.
As disclosed in Japanese Patent Publication No. 986073.

[0003]

In the above-mentioned conventional technique, the discharge amount of the hydraulic pump is variable by rotating the pump movable swash plate, and the speed can be changed, but the capacity of the pump and the motor is changed. However, when the speed is reduced by 1: 1 or 1: 2, the range of gear change is determined by the capacity of the hydraulic pump, and therefore the range of gear change cannot be increased further. .. The present invention not only changes the discharge capacity of the hydraulic pump as in the prior art, but also makes the swash plate of the hydraulic motor movable so that the gear shift range is doubled or more. With this configuration, it is possible to use a pump or motor that is one class lower than the pump or motor used in the related art.

[0004]

The problems to be solved by the present invention are as described above. Next, the means for solving the problems will be described. That is, in the hydraulic continuously variable transmission that rotates the hydraulic pump by the rotation transmitted from the input shaft 5, sends the pressure oil discharged from the hydraulic pump to the hydraulic motor, and rotates the output shaft 6 of the hydraulic motor, The pump movable swash plate 28 of the hydraulic pump is made rotatable by the first speed change operation arm 26, and the motor movable swash plate 34 of the hydraulic motor is made rotatable by the second speed change operation arm 15. The pivot support shaft 18 is sandwiched between the joint surfaces of the casing that houses the hydraulic continuously variable transmission. Also,
The pivot 18 of the second gear shift operation arm 15 is supported over the joint surface of the casing.

[0005]

[Operation] Next, the operation will be described. That is, the rotation from the engine is transmitted to the input shaft 5 via the V belt. The rotation of the input shaft 5 causes the pump case 7 to rotate, and the pump piston 32 loosely fitted in the pump case 7 causes the pump movable swash plate 2 to move.
By rotating while contacting with 8, the pressure oil having a variable capacity is discharged. The pressure oil is sent to the hydraulic motor M via the oil passage in the L-shaped center section 4. When the pressure oil presses the motor piston 33 of the hydraulic motor M, the pressing force of the motor piston 33 is changed to the rotational force of the output shaft 6 by the motor movable swash plate 34. In the present invention, the angle of the motor movable swash plate 34 can be changed. By changing the angle of the motor movable swash plate 34, the rotational speed of the output shaft 6 can be changed while the pressure oil has the same volume. As a result, the pump movable swash plate 28
It is possible to form a two-stage transmission by the combination of the main shift and the sub shift in which the shift by the above and the shift by the motor movable swash plate 34 are combined.

[0006]

EXAMPLES Next, examples will be described. FIG. 1 shows the first of the present invention.
FIG. 2 is a plan view of the axle drive apparatus according to the embodiment with the casing upper half portion 2 removed, FIG. 2 is a sectional view taken along the line AA of the axle drive apparatus of FIG. 1, and FIG. A plan view of a state in which the casing upper half portion 2 of the axle drive device is removed, FIG. 4 is a sectional view taken along the line BB of FIG. 3, and FIG. 5 is an inner surface of the casing upper half portion 2 and the casing lower half portion 3. Sliding curved surface 2a / 3
FIG. 6 is a side sectional view of an embodiment in which the motor movable swash plate 34 is supported by a, FIG. 6 is a plan view of FIG. 5, and FIG. 7 is a perspective view of an embodiment in which the motor movable swash plate 34 is provided with detent ball holes 34a and 34b. FIG. 8 is a front sectional view showing a stopper surface of the motor movable swash plate 34 having a two-step operation structure, FIG. 9 is a hydraulic circuit diagram of the two-step operation structure, and FIG. 10 is a hydraulic circuit diagram of a stepless operation structure. 11 is a front sectional view of an embodiment in which the motor movable swash plate 34 is constituted by the trunnion shaft 13, and FIG. 12 is a front sectional view of an embodiment in which the pivot shaft 18 is supported.

1 and 2, the overall construction of an axle drive device according to a first embodiment of the present invention will be described. The casing constituting the outside of the axle drive device is the casing upper half 2
The lower casing half 3 is configured to be vertically separable into two parts by a horizontal plane that passes through the shaft centers of the axles 1L and 1R. Therefore, the bearings of the axles 1L and 1R are sandwiched between the upper half 2 of the casing and the lower half 3 of the casing. Further, in the embodiment of FIGS. 1 and 2, the second shift operation arm 15 for rotating the motor movable swash plate 34 of the hydraulic motor M on the upper and lower joint surfaces of the casing upper half 2 and the casing lower half 3. The bearing portion of the pivot shaft 18 is also held.

Along the joining surface between the upper casing half 2 and the lower casing half 3, the lower surface of the upper casing half 2 is L-shaped.
A mold center section 4 is additionally provided, and the hydraulic pump P is supported on the pump sliding surface 4a of the L-shaped center section 4. The hydraulic pump P includes an input shaft 5 and a pump movable swash plate 2.
8, a thrust bearing 10, a pump piston 32, a pump case 7, and the like. The input shaft 5 is bearing-supported by the upper half 2 of the casing and the L-shaped center section 4.

A hydraulic motor M is supported on the motor sliding surface 4b of the L-shaped center section 4. Hydraulic motor M
Is the output shaft 6, the motor movable swash plate 34, and the thrust bearing 16.
And the motor case 8 and the motor piston 33. Then, the pressure oil discharged from the hydraulic pump P is supplied to the hydraulic motor M by the closed circuit formed in the L-shaped center section 4, and is output as the rotation of the output shaft 6. An oil filter 29 is arranged between the L-shaped center section 4 and the inside of the bottom surface of the lower half 3 of the casing, and the working oil filtered by the oil filter 29 is stored in the closed circuit of the hydraulic continuously variable transmission. When the working oil is reduced and a negative pressure is generated, the working oil is sucked through the check valve. By-pass valve operation unit 22 for forcibly opening the check valves simultaneously
22 is provided, and the bypass valve operating portions 22 and 22 are provided.
The bypass valve operating arm 24 and the bypass valve operating shaft 48.
By forcibly opening the bypass valve operating shaft 25 and the bifurcated operating body 23, the pressure oil in the closed circuit is opened to the bypass circuit, and the hydraulic motor M is freely rotatable.

The pump movable swash plate 28 of the hydraulic pump P is rotated by a first gear shift operation arm 26 fixed to a pivot shaft 27 projecting from the upper surface of the upper casing half 2. The rotation of 27 is transmitted to the lever 31 via the lever arm 30 to rotate the pump movable swash plate 28. As the pump movable swash plate 28 rotates, the thrust bearing 10 in contact with the head of the pump piston 32 inside the pump movable swash plate 28 also tilts. The amount of oil discharged from the pump P is changed.

On the other hand, according to the present invention, the motor movable swash plate 34 of the hydraulic motor M can also be rotated and changed via the second gear shift operation arm 15 and the pivot shaft 18. In the embodiment shown in FIGS. 1 and 2, the pivot shaft 18 is provided at the joining surface between the casing upper half 2 and the casing lower half 3,
It is supported by sandwiching the bearing bush. The thrust bearing 16 is also disposed inside the motor movable swash plate 34, and the motor case 8 rotates while the head of the motor piston 33 contacts the thrust bearing 16.

The rotation of the output shaft 6 of the hydraulic motor M is transmitted to the engraved small-diameter gear 35, and power is transmitted to the ring gear 17 of the differential gear device meshing with the engraved small-diameter gear 35.
The diff gear device includes a ring gear 17 and a side gear 36.3.
6 and the pinion gears 37, 37, and differential rotation is transmitted to the axles 1L, 1R. A brake plate 19 is fixedly provided at the end of the output shaft 6, and a brake shaft 20 and a brake lever 21 to which a cam braking plate that is freely contactable with the brake plate 19 is fixed are provided.

Next, a second embodiment shown in FIGS. 3 and 4 will be described. In this embodiment, the case of FIGS. 1 and 2 is different in that the arrangement of the pivot shaft 18 is different. That is, as clearly shown in FIG. 4, the upper portion of the pivot shaft 18 is supported by the casing upper half portion 2 as a bearing so as to project therethrough, and the lower portion of the pivot shaft 18 is bushed on the inner surface of the casing lower half portion 3. Is supported through. In the case of this embodiment, there is an advantage that the operation direction of the second speed change operation arm 15 and the operation direction of the first speed change operation arm 26 are the same. Other configurations are the same as those of the embodiment shown in FIGS.

Next, a description will be given of the embodiment shown in FIGS. The pivot shaft 18 is supported on the joint surface between the casing upper half 2 and the casing lower half 3, and the entire motor movable swash plate 34 is provided in the casing upper half 2 and the casing lower half 3. It is supported by the sliding curved surfaces 2a and 3a. The operation arm 14 is fixed to a portion where the pivot shaft 18 projects inside the casing, and the motor movable swash plate 34 is rotated by the pin 14a at the tip of the operation arm 14.

In the embodiment of FIGS. 5 and 6, the motor movable swash plate 34 is provided with detent ball holes 34a and 34b, and the detent ball 11 protruding from the casing side by the biasing spring 11a is inserted into the detent ball hole. 34a
It is fitted in 34b. In this way, the rotation position of the motor movable swash plate 34 is set to a fixed position by the detent ball holes 34a and 34b and the detent ball 11, and the auxiliary gear shift by the rotation of the motor movable swash plate 34 is not stepless, but substantially. Two
It can be regulated gradually. By increasing the number of detent ball holes, it is possible to make the sub-speed shift multi-stage. In FIG. 7, the detent ball hole 3
A motor movable swash plate 34 having holes 4a and 34b is shown.

8 and 9, instead of the detent ball holes 34a and 34b and the detent ball 11, a casing upper half 2 and a casing lower half 3 are used as stoppers.
An example is shown using a wall of the. That is, the casing upper half 2 is provided with the low speed side stopper surface 2b, and the casing lower half 3 is provided with the high speed side stopper 3b.
Is provided. The motor movable swash plate 34 is rotated between the low speed side stopper surface 2b and the high speed side stopper 3b, and the state where it is in contact with one of the stopper surfaces is the detent position. It is said that.

Although the structure of FIG. 8 is a structure which is operated by an artificial operation force, it can be operated by hydraulic pressure. The hydraulic circuit diagram is shown in FIG. In FIG. 9, the operating lever L causes the driver's seat to switch the subtransmission control valve V to extend and contract the subtransmission cylinder S. The amount of expansion and contraction of the sub speed change cylinder S is transmitted to the second speed change operation arm 15 and the pivot shaft 18 to rotate the motor movable swash plate 34. As shown in FIG. Surface 2b
Since there is the high speed stopper 3b, the detent state occurs at this position. As a result, the second gear shift operation is restricted.

In FIG. 10, the low speed side stopper surface 2b and the high speed side stopper 3 as shown in FIGS.
b is not provided, and by operating the operating lever L, the auxiliary transmission control valve V is switched, the auxiliary transmission cylinder S is expanded and contracted, and the second transmission operating arm 15 and the pivot shaft 18 are used to drive the motor. The movable swash plate 34 can be operated steplessly. Therefore, the auxiliary shift control valve V is provided with the neutral position.

In the embodiment of FIG. 11, the trunnion shaft 13 is projected to the side of the motor movable swash plate 34, the trunnion shaft 13 is supported by the casing as a bearing, and the motor movable swash plate 34 is rotated. Shows. Trunnion shaft 13
In this case, the operating force of the motor movable swash plate 34 becomes large. Further, in FIG. 12, the motor movable swash plate 34
An embodiment is shown in which a shaft supporting shaft 18 is supported by a bearing at a position away from and the motor movable swash plate 34 is rotated by operating the shaft supporting shaft 18. In this case, there is an advantage that the operation force for rotating the motor movable swash plate 34 is slightly reduced.

[0020]

Since the present invention is configured as described above, it has the following effects. That is, the gear change range can be made wider by changing the displacement of the hydraulic pump and the displacement of the hydraulic motor, as compared with the conventional axle drive device.

Further, the pivot shaft 18 for operating the motor movable swash plate 34 of the hydraulic motor is stably supported by utilizing the joint surface of the casing for housing the hydraulic continuously variable transmission, and is easy to assemble.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which a casing upper half portion 2 of an axle drive device according to a first embodiment of the present invention is removed.

FIG. 2 is a cross-sectional view taken along the line AA of the axle drive device of FIG.

FIG. 3 is a plan view showing a state in which an upper casing half 2 of an axle drive device according to a second embodiment of the present invention is removed.

FIG. 4 is a sectional view taken along the line BB of FIG.

5 is a side sectional view of an embodiment in which a motor movable swash plate 34 is supported by sliding curved surfaces 2a, 3a on the inner surfaces of a casing upper half 2 and a casing lower half 3. FIG.

FIG. 6 is a plan view of FIG.

7 is a detent ball hole 34a in the motor movable swash plate 34. FIG.
-The perspective view of the Example which provided 34b.

FIG. 8 is a front sectional view showing a stopper surface of a motor movable swash plate of a bridge having a two-step operation structure.

FIG. 9 is a hydraulic circuit diagram of a two-stage operation structure.

FIG. 10 is a hydraulic circuit diagram in the case of a continuously variable operation structure.

11 is a front sectional view of an embodiment in which a motor movable swash plate 34 is pivotally supported by a trunnion shaft 13. FIG.

FIG. 12 is a front sectional view of an embodiment supported by a second gear shift operation shaft 18.

[Explanation of symbols]

 2 Casing upper half part 3 Casing lower half part 15 Second speed change operation arm 18 Pivot shaft 26 First speed change operation arm 27 Pivot shaft 28 Pump movable swash plate 34 Motor movable swash plate

Claims (2)

[Claims] 1. A hydraulic continuously variable transmission in which a hydraulic pump is rotated by rotation transmitted from an input shaft 5, pressure oil discharged from the hydraulic pump is sent to a hydraulic motor, and an output shaft 6 of the hydraulic motor is rotated. In the apparatus, the pump movable swash plate 28 of the hydraulic pump is made rotatable by the first speed change operation arm 26, and the motor movable swash plate 34 of the hydraulic motor is made rotatable by the second speed change operation arm 15 to make the second speed change. Operating arm 1
The pivot shaft 18 of 5 accommodates the hydraulic continuously variable transmission,
An axle drive device characterized by being sandwiched between the joint surfaces of a casing. 2. A hydraulic continuously variable transmission that rotates a hydraulic pump by rotation transmitted from an input shaft 5, sends pressure oil discharged from the hydraulic pump to a hydraulic motor, and rotates an output shaft 6 of the hydraulic motor. In the device, the pump movable swash plate 28 with which the pump piston 32 of the hydraulic pump abuts is made rotatable by the first speed change operation arm 26, and the motor movable swash plate 34 with which the motor piston 33 of the hydraulic motor abuts. Axle drive which is rotatable by a two-speed operation arm 15, and a pivot shaft 18 of the second speed-change operation arm 15 is supported across a joint surface of a casing accommodating the hydraulic continuously variable transmission. apparatus.