JPH09188150A - Axle driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a force from forcibly applying on the joint surface by setting a pump mounting surface for mounting a hydraulic pump of an integral oil passage plate which has a first and a second surfaces orthogonal to each other off a joint surface of a mission case including a half upper and a half lower cases. SOLUTION: The bearings of an axle and a driving output shaft 5 are sandwiched by the joint surfaces of an upper half case 1 and a lower half case 2 and a mounting surface 2a is constituted on the bottom inner surface of the half lower case 2 to thereby mount an oil passage plate in a state of mounting and supporting a hydraulic pump P and a hydraulic motor M on the mounting surface 2a with bolts 39 from below. Since the joint surface of a mission case and the mounting surface of the hydraulic pump P mounted on the oil passage plate are set off, the force applied on the mounting surface of the hydraulic pump P is not directly applied on the joint surface of the mission case, thereby improving durability of the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an HST type axle drive device used as a propulsion device for a tractor.

[0002]

2. Description of the Related Art Heretofore, it has been well known that an axle drive device supporting an axle is provided with an HST type transmission device for driving the axle outside the case. For example, Japanese Utility Model Publication No. Sho 62-44198 filed by the same applicant.

[0003]

However, in the prior art, the HST type transmission, which is prepared separately from the axle driving device, is exposed and fixed to the outside of the case of the axle driving device, and the entire axle driving device is provided. It was large and the total weight was heavy. In addition, a drive tank and an HST type transmission are provided because a reserve tank for replenishing the reduction of the operating oil in the HST type transmission is required, or the lubricating oil in the drive case is used as the operating oil. The problem was that the connecting pipes and oil passages had to be specially constructed. According to the present invention, an HST transmission including a hydraulic pump, a hydraulic motor and an oil passage plate is provided inside a mission case, and the oil passage plate constitutes a mounting surface of the hydraulic pump and the hydraulic motor. The mounting surface of the hydraulic pump
The halved upper case and the halved lower case that form the mission case are arranged at offset positions with respect to the peripheral joint surface.

[0004]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. An HST transmission and a two-part mission case for attaching a pair of axles 13, 13 that are differentially connected and extend oppositely between the upper half case 1 and the lower half case 2. Axle drive with; jointed along the peripheral joint surface, almost flat and horizontal,
A transmission case including a half upper case 1 and a half lower case 2; a hydraulic pump P; having an associated motor shaft 5,
Hydraulic motor M mounted inside the mission case;
The motor shaft 5 and the axle 13 extend along substantially horizontal perimeters of the upper half case 1 and the lower half case 2; the first and second axes can be positioned in the mission case and are substantially perpendicular to each other. Integrated oil passage plate 3 having a surface; the first surface is a pump mounting surface for mounting the hydraulic pump P, and the second surface is a motor mounting surface for mounting the hydraulic motor M; And an axle drive having a pump mounting surface offset from the plane defined by the peripheral interface.

[0005]

The objects and configurations of the present invention are as described above, and the embodiments of the invention shown in the accompanying drawings will be described below. 1 is a side view of a small tractor equipped with an axle drive device of the present invention, FIG. 2 is a front sectional view of the axle drive device of the present invention, and FIG. 3 is a view of FIG. 2 with a half upper case 1 removed. XX cross-sectional view, FIG. 4 is a YY arrow cross-sectional view of FIG. 2, FIG. 5 is a perspective view of the oil passage plate, FIG. 6 is a side view thereof, and FIG. 7 is a plan view of the oil passage plate mounting surface portion. Is. FIG. 1 shows a small tractor on which an engine E having a vertical crankshaft is mounted.

A pulley is fixed to the vertical crankshaft of the engine E, and power is transmitted by a belt to the pulley fixed to the pump shaft 4 of the hydraulic pump P protruding upward from the axle drive device of the present invention. is there. The tractor has
Rotary mowers R and R'are attached to the front or abdomen to perform lawn mowing work. The present invention relates to an axle drive device that drives an axle 13 of the tractor. 2, 3 and 4, the configuration of the axle drive device will be described in detail. The case of the axle drive device is composed of upper and lower half cases 1 and 2, and both cases are joined together to form a single sealed mission case. The bearings of the axles 13 and 13 and the drive output shaft 5 are held between the joint surfaces of the upper half case 1 and the lower half case 2. Further, an attachment surface 2a is formed on the inner surface of the bottom of the half lower case 2, and the oil passage plate 3 in a state in which the hydraulic pump P and the hydraulic motor M are mounted and supported on the attachment surface 2a.
Can be attached from below with bolts 39, 39, ....

With the oil passage plate 3 with the hydraulic motor M and the hydraulic pump P attached to the lower half case 2, the upper half case 1 is joined to cover the upper half case 1 from above, and the upper half case is joined. The case 1 and the lower half case 2 are fastened with bolts. By constructing both the upper half case 1 and the lower half case 2 by aluminum die casting, the machining portion is reduced and the cost is reduced. HST to be housed inside the axle drive of the present invention
The variable speed transmission is composed of a hydraulic pump P, an oil passage plate 3 and a hydraulic motor M, and a pump mounting surface 3d and a motor mounting surface 3e are formed on the orthogonal planes provided on the upper and side portions of the oil passage plate 3. It is composed.

Pump mounting surface 3d and motor mounting surface 3e
A pair of half-moon shaped oil passages are formed in the mounting surface of
As a pair of half-moon shaped oil passages on the motor mounting surface 3e, 3a, 3
b is formed by casting, and as a pair of half-moon shaped oil passages on the pump mounting surface 3d, 3a 'and 3b' are formed by casting downward, and the oil passage 3a 'communicates with the oil passage 3k. The oil passage 3i communicates with the oil groove 3i, and the end of the oil passage 3i communicates with the oil passage 3a of the motor mounting surface 3e. Oil passage 3b 'is oil passage 3
j, and communicates with the oil groove 3h through the oil passage 3j, and the end of the oil groove 3h is connected to the oil passage 3b of the motor mounting surface 3e. That is, as shown in FIGS. 4 and 5, the oil passage plate 3 has a back surface on the side opposite to the pump mounting surface 3d as a fixed surface 3g of the oil passage plate, and the fixed surface 3g has a hydraulic oil suction port 3c and an oil. Groove 3
The h, 3i and the suction port 3f are provided. However, the hydraulic oil suction port 3c, the oil grooves 3h and 3i, and the suction port 3f can be formed by machining, but in order to reduce the processing cost, they are integrally molded and cast during the molding of the oil passage plate 3. Has been done.

Between the oil grooves 3i and 3h of the oil passage plate 3, a replenishment oil passage 30 provided with check valves 26 and 27 is bored by drilling, and between the check valves 26 and 27. The hydraulic oil suction port 3c extending downward is provided.
A lower half case 2 is provided at the lower end of the hydraulic oil suction port 3c.
A wide suction port 3f for sucking hydraulic oil from a sponge-shaped oil filter 8 fitted to the air passage is provided in communication with the sponge-shaped oil filter 8,
The suction port 3f faces the oil filter 8. In order to make the surface 2a and the top surface of the filter 8 the same in the oil passage plate mounting surface 2a of the half lower case 2, a filter mounting hole 2b is formed, and a suction chamber 2c is further formed below it. ing. A lubricating oil inlet 2d is provided outside the oil passage plate mounting surface 2a.
Are formed and are connected to the suction chamber 2c. The lubricating oil in the case is sucked from the bottom and one side of the filter 8.

Thus, through the hydraulic oil inlet 3c and the check valves 26 and 27, the oil grooves 3i and 3h and the oil passages 3a and 3 are provided.
Since b, 3a ′, 3b ′ are communicated with each other, when the hydraulic oil decreases due to the operation of the hydraulic motor M and the hydraulic pump P, negative pressure is generated in the oil passages 3a, 3b, and the oil filter 8 More, the lubricating oil in the case is sucked as working oil. Further, the fixed surface 3g of the oil passage plate 3 is fixed by the bolts 39, 39 ... In accordance with the oil passage plate mounting surface 2a provided on the inner bottom surface of the lower half case 2, and thus, The suction port 3f and the oil grooves 3h and 3i are closed by the oil passage plate mounting surface 2a, and the oil grooves 3h and 3i serve as oil passages. Of course, the fixed surface 3g of the oil passage plate 3 and the oil passage plate mounting surface 2a
A seal member 4 such as a gasket or hydraulic packing is provided between
0 is interposed so as to reduce the leakage of hydraulic oil as much as possible.

A cylinder block 10 of a hydraulic pump P is rotatably mounted on the pump mounting surface 3d, and a piston 12 is slidably fitted in a plurality of piston holes of the cylinder block 10. . When the pump shaft 4 supported by the bearing of the half upper case 1 and the spherical bush of the pump mounting surface 3d is rotated, the cylinder block 10 and the piston 12 rotate, and the thrust bearing 15 contacting the upper end of the piston 12 is moved. By changing the angle by the swash plate 9, the discharge amount and discharge direction of the hydraulic pump P are changed, and the discharge pressure oil is transferred to the oil passages 3a 'and 3b' of the oil passage plate 3.
Oil passages 3k, 3j, oil grooves 3i, 3h, oil passages 3a, 3b
The oil is sent to the hydraulic motor M via. The angle of the swash plate 9 can be changed in association with the rotation of the speed change lever shaft 6, and at the neutral position of the speed change lever shaft 6,
The detent device 20 is configured.

Further, as shown in FIGS. 2 and 4, a short circuit valve 25 for short-circuiting the two oil passages 3a and 3b on the discharge side and the return side is arranged, and when the body of the tractor is towed, etc. The hydraulic motor M side is driven so as to avoid a situation in which hydraulic oil is sent to the hydraulic pump P side. Reference numeral 7 denotes an operation unit for operating the short-circuit valve 25. The short-circuit valve 25 and the operation unit 7 are of a push operation type in which the engagement state is eliminated so that the operation can be performed in the contact state. With this configuration, assembly becomes possible. A cylinder block 11 is rotatably mounted on the surface of the motor mounting surface 3e of the oil passage plate 3, and the piston 14 is pressed by the pressure oil from the oil passages 3a and 3b, and the thrust bearing 16 is inclined by the piston 14. The cylinder block 11 and the drive output shaft 5 rotate by extending while contacting with.

A spherical bush is used for a shaft support portion of the drive output shaft 5 on the oil passage plate 3 side, and a spherical bush is also used for the other end side, and is held between upper and lower half cases 1 and 2.
A gear 17 is engraved on the drive output shaft 5, and the gear 17 meshes with a gear 21 on a counter shaft 24.
The small-diameter gear 22 on the counter shaft 24 meshes with the ring gear 23 of the differential gear device D, and the differential gear device D
The differential rotation is given to drive the axles 13, 13. Further, the tip of the drive output shaft 5 extends out of the mission case, and the brake drum 18 is fixedly installed.
The brake shoe is opened and expanded by the brake lever 19 to come into contact with the brake drum 18 for braking. In FIG. 6, the portion of the motor mounting surface 3e with which the cylinder block 11 of the hydraulic motor M abuts is shown.

[0014]

As described above, the present invention has the following advantages. First, by offsetting the joint surface of the transmission case formed by the upper half case 1 and the lower half case 2 from the mounting surface of the hydraulic pump P provided on the oil passage plate 3, the mounting of the hydraulic pump P is performed. The force related to the surface is not directly applied to the joint surface of the mission case, and the bolts and nuts for fastening the joint surface are not unduly applied. In addition, since there is a high possibility that the longitudinal axis of the motor shaft 5 of the hydraulic motor M and the mounting surface of the hydraulic pump P will be offset, an excessive load is applied like the rotational axis of the motor shaft 5 and the mounting surface. It was possible to shift the surface and improve the durability. Further, by offsetting the mounting surface of the hydraulic pump P and the joint surface of the transmission case, the degree of freedom in designing the shape of the oil passage plate 3 can be increased.

Second, since the HST type transmission for driving the axle 13 is arranged inside the transmission case in which the upper half case 1 and the lower half case 2 are joined, the HST type transmission as in the prior art is used.
Since the case of the HST type transmission itself, such as when the ST type transmission is fixed outside the case, can be eliminated, the overall size and weight of the axle drive device can be reduced. Is.

Thirdly, the hydraulic pump P and the hydraulic motor M
Since the vehicle is stored in the transmission case of the axle drive device, the axle drive means can be attached even when the installation space on the vehicle body is small, such as in a small tractor. In addition, since the oil passage that connects the hydraulic pump P and the hydraulic motor M to each other can be formed in the oil passage plate 3, it can be formed by punching at the same time when the oil passage plate 3 is formed and processed. Also has the advantage that it can be reduced. Further, since the oil passage plate 3 is fixedly installed inside the transmission case, the mounting portion of the hydraulic pump P and the hydraulic motor M are fixed.
All oil leaks that occur at the mounting part of the will return to the mission case, and the outside of the mission case will not be contaminated.

[Brief description of the drawings]

FIG. 1 is a side view of a small tractor provided with an axle drive device of the present invention.

FIG. 2 is a front sectional view of the axle drive device of the present invention.

FIG. 3 is a sectional view taken along the line XX in FIG. 2 with the upper half case 1 removed.

FIG. 4 is a sectional view taken along the line YY of FIG. 2;

FIG. 5 is a perspective view of an oil passage plate.

FIG. 6 is a side view of the same.

FIG. 7 is a plan view of an oil passage plate mounting surface portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Half upper case 2 Half lower case 3 Oil passage plate 3a, 3b Oil passage 3c Hydraulic oil suction port 3d Pump mounting surface 3e Motor mounting surface 4 Drive input shaft 5 Drive output shaft P Hydraulic pump M Hydraulic motor

Claims (1)

[Claims] 1. A HST transmission and a pair of axles for differentially connecting and opposingly extending between the upper half case 1 and the lower half case 2 for mounting. Axle drive with partial mission case; transmission case including half upper case 1 and half lower case 2 joined along a peripheral joint surface that is almost flat and horizontal; hydraulic pump P; Hydraulic motor M having a motor shaft 5 and mounted inside the mission case; the motor shaft 5 and the axle 13 extend along a substantially horizontal periphery of the half upper case 1 and the half lower case 2; the mission case An integral oil passage plate 3 which is positionable in and has approximately first and second surfaces approximately at right angles to each other; the first surface being a pump mounting surface for mounting the hydraulic pump P, and the second surface Surface is hydraulic motor M An axle drive having a pump mounting surface within the mission case and offset from a plane defined by a peripheral joint surface.