JP3987609B2 - Axle drive - Google Patents

Description

[0001]
BACKGROUND 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 (hereinafter referred to as HST), and a cooling structure for the oil.
[0002]
[Prior art]
Conventionally, an HST formed by fluidly connecting a hydraulic pump and a hydraulic motor, a differential gear device, an axle, and a gear train that is a power transmission mechanism from the motor shaft of the HST to the differential gear device are housed in a housing in which an oil sump is formed. In this, the housing is partitioned into a first chamber that houses the HST hydraulic pump and the hydraulic motor, and a second chamber that houses the differential gear device and the gear train. A technique for disposing a reservoir above a chamber is known from Japanese Patent Laid-Open No. 3-159822.
[0003]
[Problems to be solved by the invention]
However, in the prior art described above, the reservoir projects upward from the housing, and a large space in the vertical direction is required to attach the axle drive device to the vehicle.
In addition, the reservoir disposed above is positioned in parallel with the input shaft of the HST hydraulic pump protruding substantially vertically above the housing, and from the cooling air area of the cooling fan attached to the input shaft. The oil in the reservoir was not cooled by the cooling fan. If the oil is not cooled sufficiently, there is a problem that the oil temperature rises and the operation of the HST does not go smoothly.
[0004]
[Means for Solving the Problems]
The present invention uses the following means in order to solve the above problems in the axle drive device.
In claim 1, to accommodate the HST therein to form a reservoir first oil in the housing (X), and substantially not perpendicular to protrude above the housing the HST input shaft (3), the cooling fan (24) is mounted, and a second oil sump (Y) for adjusting the volume change of the oil in the first oil sump (X) is disposed below the cooling fan (24), and the first oil The oil is configured to flow freely between the reservoir (X) and the second oil reservoir (Y).
In the present invention, the oil level (LO) of the second oil sump (Y) is positioned at a lower level than the oil level (L1) of the first oil sump (X).
[0005]
In claim 3, the first oil sump (X) is formed in the housing so as to be shielded from the atmosphere to accommodate the HST, while the volume change of oil in the first oil sump (X) is adjusted. both the sump second oil to the (Y) configured to be opened to the atmosphere via a capillary (27) between said first oil reservoir (X) and sump second oil (Y) mutually The tip of the narrow tube (27) communicating with the first oil sump (X) is inserted into the oil level (LO) of the oil stored in the second oil sump (Y) and extends to the vicinity of the inner bottom. And is always located in the second oil sump (Y) .
[0006]
In claim 4, a cooling fan (24) is provided by projecting the input shaft (3) of the HST outward of the housing, and the second oil sump (in the cooling air area of the cooling fan (24)) is provided. Y) is disposed.
In claim 5, the oil level (LO) of the second oil sump (Y) is set at a lower level than the oil level (L1) of the first oil sump (X).
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings. 1 is a plan view of an axle drive device, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is an enlarged view of a communication portion between the first oil sump and the second oil sump in FIG. Similarly, FIG. 5 is a perspective view of the reservoir tank and its mounting member, and FIG. 6 is a communication view of the first oil sump and the second oil sump. It is a perspective view of the pipe joint which is a member.
[0008]
The overall configuration of the axle drive device will be described with reference to FIGS. The housing of the axle drive device is configured 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 axles 7 and 7 and the motor shaft 4 are rotatably supported by bearings sandwiched between the housings 1 and 2. The axles 7 and 7 are differentially coupled by a differential gear device (not shown), and both ends of the axles 7 protrude outward in the left and right directions of the housing.
[0009]
A first oil sump X for filling lubricating oil and oil serving as HST hydraulic oil is formed inside the housing. A reservoir 25 described later is installed on the outer wall surface of the housing. Y is formed. In the housing, an HST comprising a hydraulic pump P, a hydraulic motor M, and a center section 5 that fluidly joins both, a differential gear device, and power for transmitting power from the motor shaft 4 of the hydraulic motor M to the differential gear device. A transmission mechanism is accommodated.
[0010]
The center section 5 fixed in the oil sump X has a horizontal portion and a vertical portion, a pump-equipped surface 50 is formed on the upper surface of the horizontal portion, and the cylinder block 16 is rotatably disposed on the pump-equipped surface 50. ing. The pistons 12, 12,... Are reciprocally fitted in a plurality of cylinder holes of the cylinder block 16 via biasing springs, and the heads of the pistons 12, 12,. The input shaft 3 also serving as a pump shaft is integrally disposed on the rotational axis of the cylinder block 16 to constitute a hydraulic pump P. The upper part 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.
[0011]
Then, by tilting the piston contact surface of the movable swash plate 11 with respect to the rotational axis of the cylinder block 16, the oil discharge amount and the discharge direction from the hydraulic pump P are changed. A control shaft 35 is rotatably supported on the side wall of the upper housing 1, an arm that engages the side surface of the movable swash plate 11 is provided at one end of the control shaft 35, and a control lever 36 is fixed to the other end. It is connected to a shift operation tool such as a pedal or a lever provided in the vehicle via a link or the like. Reference numeral 38 denotes a shock absorber provided between the control lever 36 and the lower housing 2 so as to relieve shock at the time of shifting operation.
[0012]
A surface with a motor is formed on the side surface of the vertical section of the center section 5, and a cylinder block and a piston having the same configuration as the hydraulic pump P are provided, and the head of the piston is in contact with a fixed swash plate fixed to the housing. The motor shaft 4 is integrally arranged on the rotation axis of the cylinder block to constitute the hydraulic motor M. Power is transmitted from the motor shaft 4 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.
[0013]
Next, the reservoir 25 according to the present invention will be described. The reservoir 25 is made of synthetic resin or the like, and is a rectangular parallelepiped tank as shown in FIGS. 3 and 5, in which a second oil sump Y for accumulating a small amount of oil is formed. An oil supply port 25a is provided on the upper surface of the reservoir 25. The oil supply port 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 sump X is a closed space so as to be cut off from the atmosphere.
[0014]
First locking means 25b and 25b, which are groove-shaped or hollow-shaped recesses along the left-right direction, are provided on two opposing surfaces of the reservoir 25, in this embodiment, both front and rear surfaces. In addition, this 1st latching means 25b * 25b is good also as a rail-shaped or protrusion-shaped convex part.
[0015]
An opening 25 c is provided on one side of the reservoir 25, in this embodiment, the front surface. The narrow tube 27 is inserted into the opening 25 c via the seal 27 a, and one end of the narrow tube 27 extends to the vicinity of the inner bottom of the reservoir 25. The siphon is formed by being always positioned in the second oil sump Y. The other end of the thin tube 27 is connected to a pipe joint 30 described later.
[0016]
The attachment member 29 for detachably fixing the reservoir 25 to the housing is formed by bending a flexible and elastic plate material made of a steel plate, a synthetic resin plate, or the like into a “U” shape. The width between the front and rear side plates 29 is substantially matched with the width of the reservoir 25 so that it can be fitted from above . Convex or concave second locking means 29a and 29a, which match the shape of the first locking means 25b and 25b, are provided on the top of the front and rear side plates, and the first locking means 25b and 25b are made elastic. So that it can be fitted.
[0017]
A notch 29b that is open upward is formed at the upper end of the front side plate, and the boss portion of the opening 25c of the reservoir 25 is positioned in the notch 29b when fitted to prevent left-right removal.
[0018]
Bolt holes 29c and 29c are opened in the central bottom plate portion of the attachment member 29 so that the bolts 32 and 32 can be fixed to the upper wall surface of the axle housing portion of the housing. As shown in FIGS. 1 and 2, the enlarged region of the housing housing the differential gear device projects vertically and rearward from the main part of the housing, so that the mounting member 29 is placed in a recessed portion on the side of the projecting portion. The shape enlargement region 1a and the reservoir 25 are overlapped with each other in a side view, and are arranged so as to fit within the width of the portion where the front HST is accommodated. The upper end of the reservoir 25 is lower than the cooling fan 24, and the reservoir 25 is disposed in the cooling air area so that the cooling air from the cooling fan 24 hits it. That is, as shown in FIGS. 1 and 4, the cooling fan 24 and a part of the reservoir 25 overlap in plan view.
[0019]
As shown in FIGS. 3, 4, and 6, the pipe joint 30 has an L-shaped oil passage 30 a therein, and one end of the oil passage 30 a opened on the lower surface thereof is opened on the upper surface of the upper housing 1. 1b and communicates with the first oil sump X in the housing. Further, as shown in FIG. 6, a fixed portion 30b is formed on the side surface of the pipe joint 30, and the fixed portion 30b communicates with the oil passage 30a. The oil hole 30c to be opened is opened. The fixing portion 30b is screwed to the upper housing 1 with a bolt, and one end of a narrow tube 27 is inserted into the oil hole 30c. In this way, the first oil sump X in the housing and the second oil sump Y of the reservoir 25 are communicated with each other via the pipe joint 30 and the thin tube 27.
[0020]
By inserting the thin tube 27 from the first oil sump X into the oil level LO of the oil stored in the second oil sump Y, the oil level LO becomes lower than the oil level L1 of the oil reaching the pipe joint 30. It is supposed to be located. When the volume of the oil in the first oil sump X is increased due to the high temperature due to the operation of the HST or the drive of the transmission mechanism, the increased amount is introduced into the reservoir 25 through the pipe joint 30 and the thin tube 27, and vice versa. When the oil temperature of the oil in the first oil sump X decreases and the volume decreases, the oil is returned from the second oil sump Y into the first oil sump X via the thin tube 27 and the pipe joint 30. Thus, the volume of oil in the first oil sump X is adjusted.
[0021]
【The invention's effect】
By configuring as described above, the present invention has the following effects.
By configuring as in the first aspect, the second oil sump is disposed below the cooling fan, so that the air from the cooling fan is efficiently received, and the oil therein can be sufficiently cooled.
[0022]
Further, in the configuration of the invention according to claim 1, by setting the oil level of the second sump as a lower level than the oil level of the first sump as described in claim 2, any type of outer wall of the housing can be obtained. It can be mounted on a place, and the whole axle drive device is made compact. In particular, when mounting on a vehicle, a large space in the vertical direction is not required.
[0023]
Further, with the configuration of the axle drive device according to the third aspect, the oil in the first oil sump of the housing can be communicated with the second oil sump via the thin tube. The volume change of the oil in the oil sump can be adjusted with a simple configuration.
Furthermore, the structure of claim 4 can sufficiently cool the oil in the second oil sump, and also exerts a cooling effect on the oil in the first sump communicating with the second oil sump. be able to.
In addition, since the second oil sump can be attached to any location on the outer wall of the housing, the entire axle drive device can be made compact, particularly when it is attached to the vehicle. Does not require a large space in the direction.
[Brief description of the drawings]
FIG. 1 is a plan view of an axle drive device.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
3 is an enlarged view of a communication portion between the first oil sump and the second oil sump in FIG. 2; FIG.
FIG. 4 is a partially enlarged cross-sectional view of the communication portion between the first oil sump and the second oil sump.
FIG. 5 is a perspective view of a reservoir tank and its mounting member.
FIG. 6 is a perspective view of a pipe joint that is a communicating member between a first oil sump and a second oil sump.
[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 tube 29 Mounting member 29a Second locking means 30 Pipe joint 30a Oil passage 30c Oil hole

Claims (5)

A first oil sump (X) is formed in the housing, and HST is accommodated therein, and an input shaft (3) of the HST is protruded substantially vertically above the housing, and a cooling fan (24) is attached. A second oil sump (Y) for adjusting the volume change of the oil in the first oil sump (X) is disposed below the cooling fan (24), and the first oil sump (X) and the second sump (X) An axle drive device characterized in that oil can flow between the two oil sumps (Y).   The oil level (LO) of the second oil sump (Y) is located at a lower level than the oil level (L1) of the first oil sump (X). Axle drive device. A first oil sump (X) is formed in the housing so as to be shielded from the atmosphere to accommodate HST, while a second oil for adjusting the volume change of the oil in the first oil sump (X) reservoir both when the (Y) configured to be opened to the atmosphere, said first oil sump (X) and sump second oil between the (Y) through intercommunicating through a thin tube (27), said first The tip of the narrow tube (27) communicating with the oil sump (X) is inserted into the oil level (LO) of the oil stored in the second oil sump (Y) and extends to the vicinity of the inner bottom, and the second oil An axle drive device characterized by being always located in the reservoir (Y). A cooling fan (24) is provided by projecting the input shaft (3) of the HST to the outside of the housing, and the second oil sump (Y) is provided in the cooling air area of the cooling fan (24). The axle drive device according to claim 3 . The axle drive device according to claim 3 or 4, wherein the oil level (LO) of the second oil sump (Y) is set at a lower level than the oil level (L1) of the first oil sump (X). .

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