JPH11108165A - Axle driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form the whole of an axle driving device in a compact size, and improve cooling efficiency of oil by installing a cooling fan in such a way that a hydrostatic transmission is housed in a first oil reservoir in a housing and its input shaft is projected nearly vertically, and arranging a second oil reservoir downward the fan for regulating change of a volume of oil in the first oil reservoir. SOLUTION: An oil reservoir X for hydraulic oil of a hydrostatic transmission (an HST) is formed inside vertical housings 1, 2, and a reservoir 25 is arranged on an outer wall surface of the housing 2 so as to form a second oil reservoir Y. The input shaft 3 of the HST is projected upward from the upper wall of an upper housing 1, and an input pulley 23 with a cooling fan 24 is fixedly arranged on an upper end of the input shaft 3. The reservoir 25 is arranged in an cooling wind area of the cooling fan 24. The reservoir 25 is communicated with the atmosphere through a cap 26 with a breather mechanism of an oil filling port 25a, and the oil reservoir X is sealed from the atmosphere. The first oil reservoir X and the second oil reservoir Y are communicated with each other through a pipe joint 30 and a narrow pipe 27. The oil level LO of the second oil reservoir Y is positioned on a level lower than the oil surface 3 of the first oil reservoir X.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrangement of a reservoir for adjusting a volume change of oil in a housing accommodating a hydrostatic transmission (HST) and a cooling structure for the oil.

[0002]

2. Description of the Related Art Conventionally, an HST in which a hydraulic pump and a hydraulic motor are fluidly connected in a housing in which an oil reservoir is formed.
2. Description of the Related Art An axle driving device including a gear train, a differential gear device, an axle, and a power transmission mechanism from a motor shaft of an HST to a differential gear device is known.
A first chamber containing a hydraulic pump and a hydraulic motor of the HST,
Japanese Patent Laid-Open Publication No. 3-1 discloses a technology in which a chamber is partitioned into a differential gear device and a second chamber for accommodating a gear train, and a reservoir is disposed above the first chamber.
No. 59,822.

[0003]

However, in the above prior art, the reservoir protrudes above the housing, and a large space in the vertical direction is required to mount the axle drive device on the vehicle. In addition, the reservoir disposed above is positioned in parallel with the input shaft of the HST hydraulic pump that projects substantially vertically above the housing, and is located in the cooling air area of the cooling fan attached to the input shaft. Was separated, and the oil in the reservoir was not cooled by the cooling fan. If the oil is not sufficiently cooled, a problem arises in that the oil temperature rises and the HST does not operate smoothly.

[0004]

The present invention uses the following means to solve the above-mentioned problems in the axle drive device. First, a means according to the first aspect of the present invention is to form a first oil sump in a housing, accommodate an HST therein, and project an input shaft of the HST substantially vertically above the housing to cool the cooling fan. At the bottom of the cooling fan, a second oil sump for adjusting the volume change of the oil in the first oil sump is arranged, and the oil is mutually transferred between the first oil sump and the second oil sump. In the invention according to the first aspect, the means taken by the second aspect is such that the oil level of the second sump is lower than the oil level of the first sump. Is to be located at

According to a third aspect of the present invention, a first oil reservoir is formed in the housing so as to be shielded from the atmosphere to accommodate the HST, while a volume change of the oil in the first oil reservoir is performed. The invention according to claim 3, wherein the second oil reservoir for adjusting the pressure is configured to be open to the atmosphere, and the first oil reservoir and the second oil reservoir are interconnected via a thin tube. According to a fourth aspect of the present invention, a cooling fan is provided by projecting an input shaft of the HST to the outside of the housing, and the second oil reservoir is disposed in a cooling air area of the cooling fan. Further, in the invention according to claim 3 or 4, the means adopted by the invention according to claim 5 is such that the oil level of the second oil sump is lower than the oil level of the second oil sump. Things.

The invention according to claim 6 is a means for accommodating HST in a housing and installing a reservoir on an outer wall of the housing for adjusting a change in volume of oil stored in the housing. 7. A method according to claim 6, wherein a first locking means is provided on each of one side surface and the other side surface of the reservoir facing each other, and a second locking means corresponding to each first locking means is provided on the housing. Means taken by the invention according to claim 7 in the invention is:
The first locking means is formed in a concave shape or a convex shape, and the second locking means is formed by forming an elastically deformable plate material into a U-shape. The fitting portion is formed in a convex or concave shape.

[0007]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view of an axle drive device, and FIG.
1 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is an enlarged view of a communicating portion between the first oil reservoir and the second oil reservoir in FIG. 2, and FIG. An enlarged plan partial cross-sectional view of the communication portion,
FIG. 5 is a perspective view of a reservoir tank and a mounting member thereof, and FIG. 6 is a perspective view of a pipe joint which is a communicating member between a first oil reservoir and a second oil reservoir.

The overall structure of the axle drive will be described with reference to FIGS. 1 and 2. The housing of the axle drive device is formed by joining the upper housing 1 and the lower housing 2 to each other at a flat joining surface along the horizontal direction.
By joining the two housings 1 and 2, the axle 7.7
And the motor shaft 4 are rotatably supported by bearings sandwiched between the housings 1 and 2. The axles 7, 7 are differentially coupled by a differential gear device (not shown), and both ends protrude to the left and right outside of the housing.

An oil reservoir X for filling lubricating oil and oil serving as HST operating oil is formed inside the housing.
A reservoir 25 described later is installed on the outer wall surface of the housing, and a second oil reservoir Y is formed in the reservoir 25. In the housing, an HS including a hydraulic pump P, a hydraulic motor M, and a center section 5 for fluidly connecting the two is provided.
T, a differential gear device, and a power transmission mechanism that transmits power from the motor shaft 4 of the hydraulic motor M to the differential gear device are housed.

The center section 5 fixed in the oil sump X has a horizontal portion and a vertical portion. A pump mounting surface 50 is formed on the upper surface of the horizontal portion, and the cylinder block 16 is rotatable on the pump mounting surface 50. Are located. Are reciprocally fitted into the plurality of cylinder holes of the cylinder block 16 via urging springs, and the heads of the pistons 12 abut against the movable swash plate 11. And
The input shaft 3 also serving as a pump shaft is integrally arranged on the rotation axis of the cylinder block 16 to constitute a hydraulic pump P. The upper portion of the input shaft 3 protrudes upward from the upper wall of the upper housing 1, and an input pulley 23 with a cooling fan 24 is fixed to the upper end thereof.

The amount and direction of oil discharge from the hydraulic pump P is changed by tilting the piston contact surface of the movable swash plate 11 with respect to the rotation axis of the cylinder block 16. A control shaft 35 is rotatably supported on the side wall of the upper housing 1.
At one end, there is provided an arm that engages the side surface of the movable swash plate 11, and at the other end, a control lever 36 is fixed, and a speed change operation tool such as a pedal or lever provided on the vehicle via a link or the like. Be linked. 38 is a control lever 36
And a lower shock absorber provided between the lower housing 2 and the lower housing 2 so as to reduce a shock at the time of a shift operation.

A motor mounting surface is formed on the side surface of the vertical portion of the center section 5, and a cylinder block and a piston having the same structure as the hydraulic pump P are provided. Hit the board,
The motor shaft 4 is integrally disposed on the rotation axis of the cylinder block to constitute the hydraulic motor M. Motor shaft 4
Power is transmitted to the differential gear device via a power transmission mechanism (not shown), and the power of the motor shaft 4 is transmitted to the left and right axles 7.

Next, the reservoir 25 according to the present invention will be described. The reservoir 25 is made of a synthetic resin or the like, and is a rectangular parallelepiped tank as shown in FIGS.
A second oil reservoir Y for storing a small amount of oil is formed therein. Lubrication port 25a is provided on the upper surface of reservoir 25.
The oil inlet 25a is closed by a cap 26 with a breather mechanism, and the inside of the reservoir 25 is communicated with the atmosphere via the breather mechanism. On the other hand, the oil reservoir X is a closed space so as to be shielded from the atmosphere.

On two opposing surfaces of the reservoir 25, that is, both front and rear surfaces in this embodiment, first locking means 25b, 25b, which are groove-shaped or concave-shaped recesses extending in the left-right direction, are provided. Note that the first locking means 25b may be formed as a rail-shaped or projection-shaped projection.

An opening 25c is provided on one side surface of the reservoir 25, in this embodiment, on the front surface.
The thin tube 27 is inserted through the small oil reservoir 7a, one end of the thin tube 27 is extended to near the inner bottom of the reservoir 25, and the second oil reservoir Y
A siphon is formed by always placing it in the room.
The other end of the thin tube 27 is connected to a pipe joint 30 described later.

The mounting member 29 for detachably fixing the reservoir 25 to the housing is formed by bending a foldable and elastic plate material such as a steel plate or a synthetic resin plate into a “U” shape. The width between the front and rear side plates of the mounting member 29 is made substantially equal to the width of the reservoir 25 so that the mounting member 29 can be fitted from above,
The first locking means 25b, 25b
Convex or concave second locking means 29a conforming to the shape of
29a is provided so that the first locking means 25b can be elastically fitted.

An upper open notch 2 is formed at the upper end of the front side plate.
9b is formed, and the opening 25 of the reservoir 25 is formed in the notch 29b.
The boss portion c is positioned at the time of fitting to prevent the boss portion from falling off in the left-right direction.

A bolt hole 2 is formed in the center bottom plate of the mounting member 29.
9c and 29c are opened so that they can be fixed to the upper wall surface of the axle housing portion of the housing with bolts 32. As shown in FIGS. 1 and 2, since the enlarged shape area of the housing in which the differential gear device is housed projects vertically and rearward from the main part of the housing, the mounting member 29 is provided in a recessed portion beside the projected portion. When fixed, the shape enlarged area 1a and the reservoir 25 are overlapped in a side view, and further disposed so as to fit within the width of the portion in front of which the HST is accommodated. The upper end of the reservoir 25 is lower than the cooling fan 24, and the reservoir 25 is
4 is arranged in the cooling air area so that the cooling air from 4 is applied. That is, as shown in FIGS. 1 and 4, the cooling fan 24 and a part of the reservoir 25 overlap in plan view.

As shown in FIGS. 3, 4, and 6, the pipe joint 30 has an L-shaped oil passage 30a therein, and one end of the oil passage 30a opened on the lower surface thereof is connected to the upper housing 1. It is inserted into the opening 1b on the upper surface and communicates with the first oil reservoir X in the housing. Further, as shown in FIG. 6, a fixing portion 30b is formed on a side surface of the pipe joint 30, and an oil passage is formed in the fixing portion 30b. An oil hole 30c communicating with 30a is opened. The fixing portion 30b is screwed to the upper housing 1 with a bolt, and the oil hole 3
One end of the thin tube 27 is inserted into 0c. Thus, the first oil reservoir X in the housing and the second oil reservoir Y of the reservoir 25 communicate with each other via the pipe joint 30 and the thin tube 27.

By inserting the thin tube 27 from the first sump X into the oil level L2 of the oil stored in the second sump Y, the oil level L2 is higher than the oil level L1 of the oil reaching the pipe joint 30. It is located at the lower level. When the temperature of the oil in the first oil reservoir X increases due to the operation of the HST or the driving of the transmission mechanism and the volume increases, the increased amount is introduced into the reservoir 25 through the pipe joint 30 and the thin tube 27, and Then, when the oil temperature of the oil in the first oil reservoir X decreases and the volume decreases, the oil is returned from the second oil reservoir Y into the first oil reservoir X via the thin tube 27 and the pipe joint 30. Thus, the volume of the oil in the first sump X is adjusted.

[0021]

According to the present invention, the following effects can be obtained by the above configuration. First, by configuring as described in claim 1, the second oil sump is arranged below the cooling fan, so that the second oil sump can efficiently receive the wind from the cooling fan and sufficiently cool the oil therein. it can.

Also, in the structure of the invention according to claim 1,
By setting the oil level of the second sump to be lower than the oil level of the first sump as described in claim 2, it is possible to attach the oil sump to any place on the outer wall of the housing, and the whole axle drive unit is compact. Especially when it is attached to a vehicle,
Does not require a large space in the vertical direction.

Further, with the configuration of the axle drive device according to the third aspect, the oil in the first oil reservoir of the housing can be communicated with the second oil reservoir through the thin tube. The volume change of the oil in the first oil sump can be adjusted with a simple structure, and the oil in the second oil sump can be sufficiently cooled by adopting the structure of the fourth aspect. A cooling effect can also be exerted on the oil in the first sump communicating with the sump. Further, by adopting the structure described in claim 5, the second oil sump can be attached to any place on the outer wall of the housing, so that the entire axle drive device can be made compact. Does not require a large space in the direction.

Further, with respect to the structure of the reverser for adjusting the change in the volume of oil in the oil reservoir of the housing and its installation, the reservoir is arranged on the outer wall of the housing with a simple structure and firmly. It can be installed and is easy to assemble during installation. In addition, with the configuration as described in claim 7, the reservoir can be attached and detached with a single touch, the configuration of the locking means is simple, it can be easily manufactured, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of an axle drive device.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged view of a communicating portion between a first oil reservoir and a second oil reservoir of FIG. 2;

FIG. 4 is an enlarged plan partial cross-sectional view of a communication portion between a first oil reservoir and a second oil reservoir.

FIG. 5 is a perspective view of a reservoir tank and a mounting member thereof.

FIG. 6 is a perspective view of a pipe joint that is a communication member between a first oil reservoir and a second oil reservoir.

[Explanation of symbols]

 X First oil sump Y Second oil sump 1 Upper housing 2 Lower housing 3 Input shaft 24 Cooling fan 25 Reservoir 25b First locking means 27 Narrow pipe 29 Mounting member 29a Second locking means 30 Pipe joint 30a Oil passage 30c Oil hole

[Procedure amendment]

[Submission date] January 21, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 5

[Correction method] Change

[Correction contents]

Claims (7)

[Claims] 1. A first oil sump is formed in a housing to receive an HST therein, and an input shaft of the HST is protruded substantially vertically above the housing to attach a cooling fan. A second sump for adjusting the volume change of the oil in the first sump is provided, and the oil is freely circulated between the first sump and the second sump. Axle drive device. 2. The axle drive device according to claim 1, wherein the oil level of the second sump is located at a lower level than the oil level of the first sump. 3. A first oil sump is formed in the housing so as to be shielded from the atmosphere to accommodate the HST, and a second oil sump for adjusting a volume change of the oil in the first oil sump is formed in the housing. An axle drive device configured to be opened to the outside and to have a first oil reservoir and a second oil reservoir communicate with each other through a thin tube. 4. A cooling fan is provided by projecting an input shaft of the HST to the outside of the housing, and the second oil reservoir is provided in a cooling air area of the cooling fan. An axle drive as described. 5. The axle drive device according to claim 3, wherein the oil level of the second sump is lower than the oil level of the second sump. 6. A structure for housing a HST in a housing and installing a reservoir on an outer wall of the housing for adjusting a volume change of oil stored in the housing, wherein one side and the other side of the reservoir facing each other. And a housing provided with a second locking means corresponding to each of the first locking means. 7. The first locking means is formed in a concave or convex shape, and the second locking means is formed by forming an elastically deformable plate material into a U-shape. 7. The axle drive device according to claim 6, wherein a fitting portion to the locking means is formed in a convex or concave shape.