JPH07323739A - Axle driving device - Google Patents

Abstract

PURPOSE:To compress longitudinal breadth of the whole of a trans-axle and shorten the overall length of a base by arranging a hydraulic pump and a hydraulic motor by way of aligning them almost in the parallel direction against the longitudinal direction of an axle. CONSTITUTION:Cylinder blocks 16L, 16R of hydraulic pumps PL, PR are installed in the vertical direction on a pump installing surface 5a, cylinder blocks 17L, 17R of hydraulic motors ML, MR are installed in the horizontal direction on a motor installing surface 5b, and a pair of combination of the left and right hydraulic pumps and hydraulic motors is arranged in one row in the cross direction. Consequently, each pair of the hydraulic pumps PL, PR and hydraulic motors ML, MR is in a state arranged so that the cylinder blocks 16L and 17L and 16R and 17R are overlapped on each other when an axle drive device is seen from the cross direction. It is possible to compress longitudinal breadth of the whole of a Trans-axle and to shorten the overall length of a base by this arrangement.

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 provided with a pair of hydraulic pumps and hydraulic motors for a pair of left and right axles.

[0002]

2. Description of the Related Art Conventionally, two sets of left and right hydraulic pumps and hydraulic motors are arranged in a housing, and the left and right hydraulic pumps are simultaneously driven by an engine so that the pressure oils from the respective hydraulic pumps are converted into respective hydraulic pressures. It sends oil to the motor and drives it,
A technique is known in which left and right axles are driven by respective left and right hydraulic motors via a power transmission device. For example, it is a technique disclosed in Japanese Utility Model Publication No. 2-135765. Further, a technique of a walk-behind mower that transmits the power from the engine to the left and right axles via separate transaxles for the left and right is also known. For example, the technology of US Pat. No. 5,127,215.

[0003]

In the above-mentioned axle drive device, in the former case, since the hydraulic pump and the hydraulic motor are arranged in the front-rear direction, the housing becomes long in the front-rear direction, and the latter is a transformer. Since the hydrostatic transmission is attached to the axle, the distance between the engine and the axle becomes long, the center of gravity moves away from the axle, it is difficult to steer, and a large force was required to lift the mower deck. Of.

[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, a pair of left and right axles housed in a housing is provided with a pair of left and right hydraulic pumps and a pair of left and right motors, respectively, which can be driven separately. Of the vehicle, the hydraulic pump and the hydraulic motor are set as a set for the left and right axles, respectively, which are arranged side by side in a direction substantially parallel to the longitudinal direction of the axle, or for a pair of left and right axles housed in the housing. In a case where a pair is provided and can be driven separately, each set of the hydraulic pump and the hydraulic motor is arranged in the housing such that at least some of them overlap each other when viewed in the left-right direction. . Further, a recess is provided in the housing between the left and right axles, and the recesses are connected to the input pulleys that drive the respective hydraulic pumps by facing the engine-side pulleys via belts.

[0005]

[Operation] Next, the operation will be described. That is, the output of the engine is transmitted to the pulley on the input shaft from the engine side pulley arranged in the recess of the housing via the belt,
Drives the hydraulic pump in the housing. By positioning the pulley in the recess of this housing, the distance between the input pulley and the engine side pulley can be shortened, and the engine (center of gravity) can be arranged near the axle. The left and right hydraulic motors are driven by the pressure oil discharged from the left and right hydraulic pumps, and the left and right axles are driven by the hydraulic motors. A pair of a combination of a hydraulic pump and a hydraulic motor is arranged in a straight line substantially parallel to the longitudinal direction of the axle 7, or at least a part of them is arranged to overlap. As a result, the distance from the axle can be shortened.

[0006]

EXAMPLES Next, examples will be described. FIG. 1 is a perspective view of a walk-behind mower equipped with an axle drive device of the present invention.
2 is a perspective view of the first embodiment of the axle drive device, FIG. 3 is a plan view and a partial sectional view of the axle drive device with the middle housing portion 1 removed, and FIG. 4 is a sectional view taken along the line AA of FIG. , FIG. 5 is B of FIG.
-B arrow sectional view, FIG. 6 is a CC sectional view of FIG. 5, FIG.
Is a perspective view of the second embodiment of the axle drive device, FIG. 8 is a plan view and a partial sectional view of the axle drive device with the upper housing half 1 removed, and FIG. 9 is a sectional view taken along the line AA of FIG. FIG. 10 shows B of FIG.
FIG. 6 is a sectional view taken along arrow B.

The overall structure of a walk-behind mower shown as an example of a self-propelled working machine equipped with the axle drive device of the present invention in FIG. 1 will be described. The handles 51, 51 project obliquely rearward from the rear portion of the machine body frame 50. The operation box 52 is disposed between the upper rear portions of the handles 51, 51. On the operation box 52, speed control levers 55, 55 for adjusting the speed of the left and right axles and the number of revolutions of the engine E are adjusted. An accelerator lever 56 and a bypass lever 60 for freely rotating the axle are provided. The parking brake is activated / deactivated above and below the grips of the left and right handles 51/51, respectively, and the axle is further driven / non-driven. The deadman lever 53 for setting the wheel and the rotation direction of the axle are switched between forward and reverse directions. Tearing lever 54L · 54R is disposed.

A mower deck 58 is mounted on the front end of the machine frame 50, and caster wheels 59, 59 are arranged on the front end of the mower deck 58.
A vertical engine E is arranged substantially above the center, and a crankshaft 22 which is an output shaft of the engine E is projected downward. As shown in FIG. 2, a twin pulley is provided at a lower end of the crankshaft 22. 21 is fixedly installed, one pulley 21a of the double pulley 21 has a built-in electromagnetic clutch 40, and the belt 20 is wound around the pulley 21a so that the cutter blade accommodated in the mower deck 58 can be driven. There is. A belt 23 is wound around the other pulley 21b to transmit power to the input pulley 25 on the input shaft 24 protruding above the housing H of the axle drive device, and transmit power to the axle drive device of the present invention. The axles 7L, 7R are driven to rotate the left and right traveling wheels 61, 61 for traveling.

The housing H of this axle drive is shown in FIG.
As shown in FIG. 3, a recessed portion Ha is formed in the center of the rear portion, and the crankshaft 22 and the double pulley 21 are disposed in the recessed portion Ha so as to face the engine E at a low position and
It is configured so that it can approach the axles 7L and 7R. Further, the housing H includes the upper housing portion 26, the middle housing portion 1 and the lower housing portion 2 in the first embodiment.
Are joined to each other at their flat joint surfaces around them, and when the axle drive device is mounted on the working machine, the two joint surfaces of the housing H are respectively located on the horizontal plane. The internal structure of the housing H is shown in FIGS. 3, 4, 5, and 6.
Will be described.

Middle housing part 1 and lower housing part 2
Various transmission parts for driving the axles 7L and 7R are housed in the first compartment of the vehicle in a substantially symmetrical manner, and the left and right center sections 5L and 5R are arranged substantially along the longitudinal direction of the axles 7L and 7R. They are arranged in parallel and fixed to the middle housing part 1 by three bolts, respectively, without distortion and stably. Transmission gears 27, 28L, 2 are provided in the second compartment between the upper housing portion 26 and the middle housing portion 1.
8R is housed, the transmission gear 27 is fixedly mounted on the input shaft 24, the upper portion of the input shaft 24 is provided with a bearing 29 in the upper housing portion 26, and the lower portion thereof is provided with a bearing 39 on the upper wall of the middle housing portion 1. It is supported substantially vertically via the. Input shaft 24 protruding outward from the upper housing portion 26
The input pulley 25 is fixed to the upper end of the. Pump shafts 3L and 3R are fixed to the left and right transmission gears 28L and 28R meshing with the transmission gear 27, respectively, to form left and right drive trains for transmitting power to the hydraulic pumps PL and PR. Then, the upper housing portion 26
The front upper wall of the is formed with an upward protruding portion,
The oil tank portion 26a communicates with the compartment, and the expansion of the working oil in the housing H is allowed through the air breather 26b attached to the upper end. The first compartment and the second
The hydraulic oil is allowed to flow in the compartment, and the air remaining in the hydraulic pump P and the hydraulic motor M in the housing H is mixed with the hydraulic oil by its driving, but a communication hole opened in the upper wall of the middle housing part 1. The air passes through the 1c and the air is in the oil tank portion 26.
The bubbles float to a and are collected in the second compartment, and the first compartment is filled with only the hydraulic oil. The upper wall of the middle housing part 1 supports midway parts of the pump shafts 3L and 3R via bearings.

The center sections 5L and 5R are formed in an L-shape when viewed from the rear, and the pump mounting surface 5a is located on the horizontal plane.
And a motor mounting surface 5b is formed on the outer vertical surface, and the hydraulic pump PL / PR is formed on the pump mounting surface 5a.
Cylinder blocks 16L and 16R are mounted in a vertical direction, and the cylinder blocks 17L and 17R of the hydraulic motors ML and MR are mounted in a horizontal direction on the motor attachment surface 5b, and the left and right hydraulic pumps PL and hydraulic motors ML are combined. ,
Also, a pair of combinations of the hydraulic pump PR and the hydraulic motor MR are arranged in a row in the left-right direction. Therefore, the hydraulic pumps PL / PR and the hydraulic motors ML / MR of each set are arranged so that their cylinder blocks 16L and 17L and 16R and 17R overlap each other when the axle drive device is viewed from the left and right. It has been arranged. In the present embodiment, almost all of the cylinder blocks overlap each other, but at least some of them may overlap each other.

The left and right hydraulic pumps PL and PR are axial piston type variable displacement hydraulic devices and are composed of the same parts. That is, the cylinder block 16L
A plurality of pistons 13 are reciprocally fitted in a plurality of cylinder holes of 16R via biasing springs, and the head of the piston 13 has a lower surface of the thrust bearing of the movable swash plates 8L and 8R. And the pump shafts 3L and 3R are inserted and engaged on the rotation axis of the cylinder block 16 to form hydraulic pumps PL and PR. The movable swash plate 8L / 8
As shown in FIG. 5, R is a leg portion 1a in which each of the shaft portions 8a protruding rearward is protruded downward from the middle housing portion 1.
A shaft portion 8b which is rotatably supported by the shaft portion 8a and which has the same axial center as the shaft portion 8a which projects forward is rotatably supported by support plates 9L and 9R attached to the outer surface of the middle housing portion 1, and the shaft portion outside the housing H. Gear shift levers 6L and 6R are fixed at the ends of the portions 8b, and the gear shift levers 6L and 6R are connected to a steering lever through a wire or the like, and the movable swash plates 8L and 8R are tilted by operating the levers. The amount and direction of discharge of oil from the hydraulic pumps PL and PR can be changed with.

Further, the left and right hydraulic motors ML and MR are axial piston type fixed displacement hydraulic devices and are composed of the same parts. That is, the cylinder block 17
Plural pistons 12 are reciprocally fitted in the plural cylinder holes L and 17R while being biased by springs. The head of the piston 12 has fixed swash plates 19L and 19R.
The fixed swash plates 19L and 19R are fixed by being sandwiched between the middle housing part 1 and the lower housing part 2. Further, the motor shafts 4L and 4R are inserted and engaged on the rotation axis of the cylinder blocks 17L and 17R so that the hydraulic motor ML.
It constitutes the MR.

In the center sections 5L and 5R, a pair of kidney ports (not shown) for connecting the suction portions and the discharge portions of the cylinder blocks 16L and 16R to the pump attachment surfaces 5a and 5a, respectively. No.) is opened, and a pair of kidney ports (not shown) for connecting the suction part and the discharge part of the cylinder blocks 17L, 17R are opened on the motor attachment surfaces 5b, 5b, respectively. Has been done. Inside the select section 5L, a pair of oil passages 5dL for connecting the pair of kidney ports of the pump attachment surface 5a and the pair of kidney ports of the motor attachment surface 5b to each other.
5eL is provided, which allows the hydraulic pump PL
And a hydraulic motor ML form a closed circuit for circulating hydraulic oil.

Similarly, inside the center section 5R, a pair of oil passages 5dR for connecting a pair of kidney ports on the pump mounting surface 5a and a pair of kidney ports on the motor mounting surface 5b to each other. 5eR is provided, which allows the hydraulic pump PR and the hydraulic motor MR to be installed.
A closed circuit for circulating the hydraulic oil is configured. Left and right hydraulic pump PL / PR cylinder block 16L
The hydraulic oil discharged from the rotation of the 16R flows through the closed circuit in the center sections 5L and 5R and the cylinder blocks 17L and 17 of the hydraulic motors ML and MR.
It is received by R and converted into the rotational torque of the cylinder blocks 17L and 17R. And hydraulic pump PL / P
The rotational torque generated by the hydraulic motors ML and MR is changed according to the degree of tilting of the R movable swash plates 8L and 8R. In this way, the center sections 5L and 5 arranged side by side
A hydrostatic transmission is configured on each R.

The oil passages 5dL and 5eL and the oil passage 5 are also provided.
Check valves 31L and 32L and 31R and 32R for replenishing hydraulic oil are provided in each of dR and 5eR. The respective inlet ports of the check valves 31L and 32L are connected to the hydraulic oil supply oil passage 5c opening on the rear surface of the pump attachment surface 5a of the center section 5L, and the respective check valves 31R and 32R have respective inlet ports. The inlet port is connected to a hydraulic oil supply passage 5c that opens to the back side of the pump attachment surface 5a of the center section 5R. Charge pumps 11L and 11R are formed on the back surfaces of the pump attachment surfaces 5a and 5a of the center sections 5L and 5R, respectively, and the lower portions of the pump shafts 3L and 3R are the pump attachment surfaces 5a of the center sections 5L and 5R.
The charge pumps 11L and 11R are driven by the lower ends of the pump shafts 3L and 3R, which penetrate through 5a. The pump cases 10L and 10R for accommodating the charge pumps 11L and 11R include oil passages 10a and 10a on the suction side and oil passages 10b on the discharge side to the charge pumps 11L and 11R.
10b is provided. Intake side oil passages 10a, 10a
Communicates with the left and right filters 15L and 15R so that the working oil in the first compartment of the housing H can be filtered and sucked, and the discharge side oil passages 10b and 10b are provided with relief valves (not shown) to discharge the discharged oil. Adjust to a predetermined hydraulic pressure, and the oil passages 10b and 10b are adjusted to the center sections 5L and 5 shown in FIG.
It communicates with the R hydraulic oil supply oil passages 5c and 5c.

The pressure oil discharged by the charge pump 11 driven by the pump shaft 3L flows from the oil passages 10b, 10b to the hydraulic oil supply passage 5c of the center section 5L, reaches the inlet port of the check valves 31L, 32L, and The low-pressure side check valve of the paths 5dL and 5eL is opened and taken into the closed circuit. On the other hand, pump shaft 3R
The pressure oil discharged by the charge pump 11 driven by the oil flows from the oil passage 10b to the hydraulic oil supply passage 5c of the center section 5R, reaches the inlet ports of the check valves 31R and 32R, and the low pressure side of the oil passages 5dR and 5eR. Open the check valve of and take it into the closed circuit. As described above, the charge pumps 11L and 11R mounted on the left and right center sections 5L and 5R are configured to simultaneously supply the working oil in the housing H into the closed circuits.

The filters 15L and 15R are inserted through through holes formed in the side wall of the lower housing portion 2 so that their tips are inserted into the oil passages 10a and 10a opened on the side surfaces of the pump cases 10L and 10R. Is configured. The filters 15L and 15R can be easily replaced from the inside of the housing H by removing the covers 15a and 15a for closing the holes at the time of replacement or maintenance inspection.
L / 15R can be inserted and removed. The check valves 31L, 31R and 32L, 32R are provided with opening pushers 33L, 34L and 33R, 34R for opening respective closed circuits.
It is projected so as to face laterally from R. The opening push rods 33L and 33R and 34L and 34R are springs 35.3.
It is urged in the protruding direction by 5, and the open push rod 33L / 34L
A pressing plate 36L is attached to the tip of the open lever 33R / 3
A pressing plate 36R is brought into contact with the tip of the 4R, and the opening pressing rods 33L, 34L and 33R.
The 4Rs can be evenly and simultaneously pushed in, and the left and right pressing plates 36L and 36R are arranged so that the inner sides thereof come into contact with each other. Elongated holes 36a and 36a are opened in the central portions of the pressing plates 36L and 36R.
A pair of pins 37a and 37a are inserted in a and 36a, respectively. The bases of the pins 37a and 37a are attached around a single cam shaft 37.

As shown in FIG. 4, the cam shaft 37 is rotatably supported by the bottom wall of the lower housing portion 2, and the lower portion thereof penetrates the lower housing portion 2 and a bypass arm 38 is fixed outside the housing. The bypass arm 38 is connected to the bypass lever 60 on the operation box 52 via a wire. Therefore, when the bypass lever 60 is operated, the bypass arm 38 is rotated in one direction, the cam shaft 37 is rotated, and the pins 37a and 37a are displaced to slide in the long holes 36a and 36a to press the pressing plate. Pushes 36L / 36R outward to release the push rod 33L / 34
L and 33R / 34R are simultaneously pressed to open the check valves 31L / 32L and 31R / 32R to open the respective closed circuits, and the motor shaft 4 of the hydraulic motors ML / MR.
L and 4R can be freely rotated at the same time. This allows the walk-behind mower to be pushed and moved by hand even if a trouble such as the engine not starting occurs.

The motor shafts 4L and 4R are housings H
Brake drum 42L / 4
A well-known band type brake device is configured by fixing 2R. In this brake device, when the deadman levers 53, 53 are released by a link means (not shown), a brake band (not shown) has a brake drum 42L, 4L.
The motor shafts 4L and 4R can be simultaneously braked by tightening at the same time as 2R. Also, the motor shaft 4L / 4
Gears 41L and 41R are provided in the middle of R, and the gears 41L and 41R are connected to the counter shafts 43L and 43R.
It meshes with the large diameter gears 44L and 44R on the R side. Further, the small diameter gears 45L / 4 on the counter shafts 43L / 43R
Final gear 46 in which 5R is fixedly mounted on axles 7L and 7R
The power from the hydraulic motors ML and MR is transmitted to the axles 7L and 7R by meshing with the L and 46R.

In the same plane as the joint surface of the middle housing part 1 and the lower housing part 2 in the housing H, the motor shaft 4L, the counter shaft 43L, and the axle 7L are rotated on the left and right sides thereof. The shaft cores are arranged substantially parallel to each other, and the rotation shaft cores of the motor shaft 4R, the counter shaft 43R, and the axle shaft 7R are arranged substantially parallel to each other on the other side. Bearing surfaces for the respective shafts are formed on the joint surface between the middle housing portion 1 and the lower housing portion 2, whereby the assembly of the axle drive device is simplified. Since the motor shafts 4L and 4R, the counter shafts 43L and 43R, and the axle shafts 7L and 7R are symmetrically arranged on the same axis, the entire housing H can be downsized and the bearing portion can be easily machined. It has become. 30 is a cooling fan mounted on the upper surface of the input pulley 25,
By rotating together with the input pulley 25, the cooling air can be blown from the upper side of the housing H to suppress the increase in the oil temperature of the working oil in the housing H. Although not shown, the engine side pulley 21b may also be provided with a cooling fan to further suppress the oil temperature rise of the hydraulic oil.

Another embodiment of the drive structure of the hydraulic pumps PL and PR is shown in FIGS. 7, 8, 9 and 10. That is, without providing the input shaft 24, the transmission gear 27, and the transmission gears 28L and 28R, each of the pump shafts 3L and 3R is projected by the housing H, and the input pulleys 25L and 25R are fixedly provided on the upper ends thereof. . A triple pulley 21 is provided at the lower end of the crankshaft 22, and belts 23L and 23R are respectively wound between the pulleys 21b and 21c and the input pulleys 25L and 25R to transmit power to the hydraulic pumps PL and PR. I have to.

The housing H of the axle drive apparatus according to the second embodiment includes an upper housing half 1 and a lower housing half 2.
The pump shafts 3L and 3R are supported by bearings held in the upper housing half portion 1 by being joined by a flat joining surface around them. Concerning the components inside the housing, the same components as those in the first embodiment described above are given the same reference numerals, and the description thereof is omitted. The input pulleys 25L and 25R are attached to the pump shafts 3L and 3R so that the heights thereof are different from each other, and the two pump shafts 3L and 3R are not separated from each other more than necessary, and thus the housing H is provided. The left and right width is being compressed. A part of the upper wall of the upper housing half portion 1 is bulged upward to form the oil tank portion 1b, and the breather 26b described above is additionally provided.

On the same plane as the joint surface of the upper housing half 1 and the lower housing half 2 of the housing H, the rotation of the motor 4L, the counter shaft 43L, and the axle 7L on one of the left and right sides thereof. The shaft cores are arranged substantially parallel to each other, and the rotation shaft cores of the motor shaft 4R, the counter shaft 43R, and the axle shaft 7R are arranged substantially parallel to each other on the other side. The upper housing half 1 and the lower housing half 2
Bearing surfaces for the respective shafts are formed on the joint surfaces of the shafts, thereby simplifying the assembly of the axle drive device. Then, the motor shafts 4L and 4R, the counter shaft 4
Since 3L and 43R and the axles 7L and 7R are symmetrically arranged on the same axis, the entire housing H can be made small and the bearing portion can be easily processed.

When the walk-behind mower equipped with the above-mentioned axle drive device is advanced straight, the operator starts the engine and grasps the deadman lever 53, 53 together with the grip portion of the handle 51, 51. Good. Then, both operations of the brake device are automatically released, and a biasing spring (not shown) interposed in the control linkage of the speed change levers 6L and 6R.
Thus, the speed change levers 6L and 6R are automatically operated simultaneously to the forward maximum speed position. Then, the axles 7L and 7R of the axle drive device simultaneously rotate the traveling wheels 61 and 61 in a direction to move them forward at the maximum speed.

Depending on the condition of the road surface, the left and right running wheels 61
-If 61 does not rotate uniformly and the body is meandering, it can be corrected to a straight running state by appropriately operating the left and right speed control levers 55, 55. When it is desired to change the traveling direction of the machine body, if either the left or right steering lever 54L or 54R is grasped while the grasping of the deadman lever 53, 53 is continued, the deadman lever 53, 53 is resisted against the biasing spring. Lever 54
The gear shift lever 6L or 6R linked to the L or 54R is operated in the decelerating direction to reduce the discharge oil amount of the hydraulic pump PL or PR on that side to decelerate the rotation of the hydraulic motor ML or MR. A relative rotation difference occurs between 7L and 7R, and the mower can be gently turned. Further, as the grip of the steering lever 54L or 54R is strengthened, the speed change lever 6L or 6R is further tilted, and the movable swash plate 8L or 8R is tilted to the reverse side beyond the neutral position. Then, the discharge direction of the hydraulic pump PL or PR on that side is reversed, and the rotation direction of the hydraulic motor ML or MR is reversed, so that the axle 7L or 7R rotates in the reverse direction, and The mower can be turned rapidly around the axle. When moving the aircraft backward, if both steering levers 54L and 54R are grasped at the same time, both hydraulic pumps PL
The PR discharge direction reverses, the hydraulic motors ML and MR rotate simultaneously in opposite directions, and the axles 7L and 7R move toward the running wheels 6.
Rotate 1 ・ 61 to the reverse side.

The axle drive device of the present invention is not limited to walk-behind mowers, but can be widely applied to various walk-behind type self-propelled working machines such as snow blowers and power carriers.

[0028]

Since the present invention is constructed as described above, it has the following effects. That is, since it is configured as in claim 1 or claim 2, the front-rear width of the entire transaxle can be greatly compressed, and the overall length of the machine body can be shortened. Further, the input pulley can be brought closer to the engine side pulley, the belt for transmitting power can be shortened, and the cost can be reduced.

According to the third aspect of the present invention, the housing can be arranged close to the engine, and the center of gravity of the working machine can be brought closer to the axle so that the working machine can be used when overcoming obstacles. It became possible to lift with a light force when lifting the part, which improved mobility.

[Brief description of drawings]

FIG. 1 is a perspective view of a walk-behind mower equipped with an axle drive device of the present invention.

FIG. 2 is a perspective view of a first embodiment of an axle drive device.

3A and 3B are a plan view and a partial cross-sectional view, respectively, in which a middle housing portion 1 of an axle drive device is removed.

4 is a cross-sectional view taken along the line AA of FIG.

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

6 is a cross-sectional view taken along the line CC of FIG.

FIG. 7 is a perspective view of a second embodiment of the axle drive device.

FIG. 8 is a plan view and a partial cross-sectional view with an upper housing half portion 1 removed of an axle drive device.

9 is a cross-sectional view taken along the line AA of FIG.

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

[Explanation of symbols]

 H housing Ha recess PL / PR hydraulic pump ML / MR hydraulic motor 1 middle housing part (upper housing half part) 2 lower housing part (lower housing half part) 7L / 7R axle 25 input pulley 24 input shaft 26 upper housing part

Claims (3)

[Claims] 1. A hydraulic pump and a hydraulic pump, wherein a pair of left and right axles housed in a housing is provided with a pair of left and right hydraulic pumps and a pair of hydraulic motors so that they can be driven separately. An axle drive device in which motors are arranged in a housing in a direction substantially parallel to a longitudinal direction of the axle. 2. A pair of left and right axles housed in a housing, wherein a pair of left and right hydraulic pumps and a pair of left and right motors are provided so that they can be driven separately. The axle drive device, wherein the hydraulic motor is arranged in the housing such that at least a part of the hydraulic motor overlaps with each other when viewed in the left-right direction. 3. The axle drive device according to claim 1,
An axle drive device characterized in that a recess is provided in the housing between the left and right axles, and an engine-side pulley is exposed to this recess and is connected to an input pulley that drives each hydraulic pump via a belt.