JP2667126B2 - Axle drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

[0003]

However, in the prior art, since the motor shaft of the hydraulic motor of the HST type transmission is arranged vertically, in order to drive the horizontally arranged axle, both of them are required. It was necessary to interpose a bevel gear device in the drive system. Further, since the transmission case and the HST-type transmission are arranged vertically, the overall height is increased, and there is a problem that a space is required when the transmission case is mounted on the abdomen of a tractor or the like. The present invention has solved such a problem.

[0004]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. A transmission case is formed by joining the upper half case 1 and the lower half case 2 which are divided vertically in the horizontal direction, and a horizontal joint surface between the upper half case 1 and the lower half case 2 is provided on the left and right sides. Axles 13 and 13 and the drive output shaft 5 are supported in parallel by bearings, and the left and right axles 13 and 1 are supported.
Place a differential gear device D during the 3, the ring gear 23 of the differential gear device D, and a small diameter gear 17 on the drive output shaft 5 work together to transmit power, hydraulic motor on of the drive output shaft 5
The hydraulic motor M and the oil
The HST type transmission is constituted by the pressure pump P,
Fixedly expressions transmission inside the transmission case, the hydraulic motor M is then provided with a shaft center in the horizontal direction, the hydraulic
The drive output shaft 5 is engaged with the motor M, and the drive input shaft 4 is further protruded vertically upward from the hydraulic pump P. A pulley is fixed above the drive input shaft 4 to input power from the engine E. Hydraulic motor M and hydraulic pump
Oil passage plate with P fixed inside transmission case M
3 is mounted and supported .

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The objects and constitutions of the present invention are as described above. Next, the constitution of the embodiment shown in the attached drawings will be explained. FIG. 1 is a side view of a compact 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, and FIG.
Is also the X in FIG. 2 with the half upper case 1 removed.
FIG. 4 is a sectional view taken along the arrow YY of FIG. 2; FIG.
6 is a perspective view of an oil passage plate, FIG. 6 is a side view of the same, and FIG. 7 is a plan view of an oil passage plate mounting surface.

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 drive input shaft 4 of the hydraulic pump P projecting upward from the axle drive device of the present invention. The tractor is provided with rotary mowers R and R 'at the front or abdomen to perform lawn mowing or the like. The invention relates to an axle drive for driving the axle 13 of the tractor.

Referring to FIGS. 2, 3 and 4, the structure of the axle drive 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. A mounting surface 2a is formed on the inner bottom surface of the lower half case 2, and the mounting surface 2a
In addition, the oil passage plate 3 in which the hydraulic pump P and the hydraulic motor M are mounted and supported can be attached from above by bolts 39, 39. With the oil passage plate 3 mounted with the hydraulic motor M and the hydraulic pump P attached to the lower half case 2, the upper half case 1 is joined from the top so as to cover the upper half case 1 from above. The half lower case 2 is fastened by 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.

The HST type transmission device housed and disposed inside the axle drive device of the present invention is composed of a hydraulic pump P, an oil passage plate 3 and a hydraulic motor M. The pump mounting surface 3d and the motor mounting surface 3e are formed on the provided orthogonal plane. A pair of semi-circular oil passages are formed in the mounting surfaces of the pump mounting surface 3d and the motor mounting surface 3e, respectively, and a pair of semi-circular oil passages 3a and 3b are punched out of the motor mounting surface 3e by casting. 3a ', 3b' as a pair of half-moon oil passages on the mounting surface 3d
Is drilled downward and the oil passage 3a 'is connected to the oil passage 3k.
Through the oil passage 3k to communicate with the oil groove 3i.
The end of i communicates with the oil passage 3a of the motor mounting surface 3e.
You. The oil passage 3b 'communicates with the oil passage 3j, and through the oil passage 3j.
The oil groove 3h communicates with the oil groove 3h.
The surface 3e is connected to the oil passage 3b. That is, as shown in FIGS. 4 and 5, the back surface of the oil passage plate 3 opposite to the pump mounting surface 3d is a fixed surface 3g of the oil passage plate, and the working oil suction port 3c and the oil The grooves 3h and 3i and the suction port 3f are provided. However, the hydraulic oil inlet 3c, the oil grooves 3h, 3
i, the suction port 3f can be formed by machining, but is formed by integrally molding and casting when forming the oil passage plate 3 in order to reduce the processing cost.

A replenishing oil passage 30 interposed by check valves 26 and 27 is formed between the oil grooves 3i and 3h of the oil passage plate 3 by drilling holes. A 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 lower half case 2,
A filter mounting hole 2b is formed, and a suction chamber 2c is further formed below the filter mounting hole 2b. A lubricating oil inlet 2d is formed outside the oil passage plate mounting surface 2a, and communicates with the suction chamber 2c. The lubricating oil in the case is sucked from the bottom and one side of the filter 8. Thus, the hydraulic oil inlet 3
c and the oil grooves 3i, 3h and the oil passages 3a, 3b, 3a ', 3b' are communicated via the check valves 26 , 27. Therefore, when the hydraulic oil is reduced by the operation of the hydraulic motor M or the hydraulic pump P, A negative pressure is generated in the oil passages 3a and 3b,
The lubricating oil in the case is sucked from the oil filter 8 as hydraulic oil.

The fixed surface 3g of the oil passage plate 3 is fixed to the oil passage plate mounting surface 2a provided on the bottom inner surface of the half-half lower case 2 with bolts 39, 39,. Therefore,
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 2
A seal member 40, such as a gasket or a hydraulic packing, is interposed between the seal member 40 and the seal member a so as to minimize leakage of hydraulic oil.

A cylinder block 10 of the hydraulic pump P is rotatably mounted on the pump mounting surface 3d, and a piston 12 is fitted into a plurality of piston holes of the cylinder block 10 so as to be slidable up and down. . When the drive input 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 in contact with the upper end of the piston 12 Is changed by the swash plate 9 to change the discharge amount and the discharge direction of the hydraulic pump P, and the discharge pressure oil is supplied to the oil passages 3a ′, 3a of the oil passage plate 3.
The oil is supplied from b ′ to the hydraulic motor M via the oil grooves 3i and 3h and the oil passages 3a and 3b. The angle of the swash plate 9 can be changed in conjunction with the rotation of the shift lever shaft 6, and the detent device 20 is configured at a neutral position of the shift lever shaft 6.

As shown in FIGS. 2 and 4, a short-circuit valve 25 for short-circuiting between the two oil passages 3a and 3b on the discharge side and the return side is disposed, for example, when the body of the tractor is towed. The configuration is such that the hydraulic motor M side is driven to prevent the pressure oil from being supplied 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 a surface of the motor mounting surface 3e of the oil passage plate 3, and presses the piston 14 with pressure oil from the oil passages 3a and 3b.
The cylinder block 11 and the drive output shaft 5 rotate when the piston 14 extends while abutting on the inclined thrust bearing 16. 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.
Is sandwiched between. A gear 17 is engraved on the drive output shaft 5, and the gear 17 is
1 is engaged. 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 is provided with a differential rotation so that the axle 1
3 and 13 are driven.

The drive output shaft 5 has a distal end extending out of the transmission case and a brake drum 18 fixedly attached thereto.
9, the brake shoe is expanded and brought into contact to perform braking.

FIG. 6 shows a portion of the motor mounting surface 3e with which the cylinder block 11 of the hydraulic motor M contacts.

[0017]

As described above, the present invention has the following advantages. First, in the prior art, since the motor shaft of the hydraulic motor of the HST type transmission is vertically arranged, in order to drive the horizontally arranged axle, a bevel gear device is required in both drive systems. It was necessary to interpose. In the present invention, by disposing the drive output shaft 5 of the hydraulic motor M in the horizontal direction, it is not necessary to separately provide a bevel gear mechanism between the drive output shaft and the differential gear device D. That is, the power transmission configuration from the drive output shaft 5 to the axle can be easily configured with gears, chains, and the like, and it is not necessary to change the power transmission direction using a bevel gear device as in the related art.

Second, since the HST-type transmission and the transmission case can be arranged side by side in the horizontal direction without disposing the transmission case and the transmission case vertically as in the prior art, the height of the completed axle driving device is reduced, Even when mounted on the abdomen of a small tractor, the height of the tractor was no longer raised. Third, the oil passage plate inside the transmission case
3 and a hydraulic motor M and a hydraulic pump
By mounting and supporting the P, all of the HST transmission
The body can be made compact and the HST type
To arrange the transmission inside the transmission case M
From the hydraulic motor M, the hydraulic pump P and the oil passage plate 3.
Pressure oil leakage can be received from the mission case
So there ’s no longer a need to completely eliminate leaks
It is. The lubricating oil of the transmission case M is HST type.
It can be used as hydraulic fluid for transmissions,
Use of lubricating oil as cooling oil for HST transmission
You can.

[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 of FIG. 2 in a state in which the half upper case 1 is also 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.

[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)

(57) [Claims] 1. A transmission case is constituted by joining a half upper case 1 and a half lower case 2 which are divided vertically in a horizontal direction, and the horizontal half of the upper half case 1 and the half lower case 2 is formed. The left and right axles 13, 13 and the drive output shaft 5 are supported in parallel on the joint surface by bearings.
A differential gear device D is arranged between the gears. The ring gear 23 of the differential gear device D and the small-diameter gear 17 on the drive output shaft 5 are interlocked so as to be able to transmit power, and a hydraulic motor is mounted on the drive output shaft 5.
-M, the hydraulic motor M and the hydraulic pressure
Configure the HST type transmission apparatus by a pump P, and fixed the HST type transmission apparatus in the interior of the transmission case, the hydraulic motor M is then provided with a shaft center in the horizontal direction, the hydraulic motor
The drive output shaft 5 is engaged with the motor M, and the drive input shaft 4 is further projected vertically upward from the hydraulic pump P. A pulley is fixedly mounted on the drive input shaft 4 to input power from the engine E. Hydraulic motor M and hydraulic pump P
Together with the oil passage plate 3 fixed inside the transmission case M
An axle drive device mounted on and supported by a vehicle.