JP2551735Y2 - Axle drive - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a construction of an axle drive device in which an axle case is provided with a pump for supplying hydraulic oil for a hydraulic transmission and for driving other hydraulic actuation devices in an axle case, so that an external oil pressure can be easily taken out. It is about.

[0002]

2. Description of the Related Art Conventionally, there has been known a technology in which a pump for supplying hydraulic oil for a hydraulic transmission and a pump for driving an external hydraulic actuator are provided inside an axle case. For example, this is a technique disclosed in Japanese Utility Model Laid-Open No. 2-51763.

[0003]

However, if two pumps are provided in the axle case as in the prior art, the axle case becomes large due to the storage space, and the cost increases due to an increase in the number of assembly steps and the number of parts. When the drive pump of the hydraulic operating device is provided on the center section or the bottom of the axle case, the drive hydraulic pressure setting valve and the like are provided outside via a piping member, and the installation space and the connection portion are sealed. The number of parts and members increased, and assembly was troublesome. Furthermore, since the return oil from the external hydraulic actuator was recirculated to the lower part of the axle case, air existing in the hydraulic equipment and piping at the initial stage of assembly was mixed into the hydraulic oil in the axle case, and the hydraulic pump This causes the operation of the hydraulic transmission to become unstable due to the air being sucked into the air.

[0004]

The present invention is configured as follows in order to solve such a problem. In claim 1, a hydraulic transmission that is interlocked with an axle and a single pump that is driven by an input shaft of the transmission are housed in an axle case, and oil discharged from the pump is used as a hydraulic transmission. In the axle drive device that can be supplied for supplying hydraulic oil and for driving other hydraulic operating devices, a supply oil setting valve and a driving oil pressure setting valve are housed in a pump case, and a discharge port of the pump is connected to each valve. Connect to the pump port, connect the working port of the supply hydraulic pressure setting valve to the hydraulic oil supply circuit of the hydraulic transmission, partially penetrate the pump case from the axle case and expose it. Is opened and connected to the hydraulic circuit of another hydraulic operating device via a piping member. According to a second aspect of the present invention, a reservoir tank which is open through a communication port is provided at an upper portion of the axle case according to the first aspect, and return oil from another hydraulic operating device is returned to the reservoir tank. It is.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problem to be solved by the present invention and the means for solving it are as described above. Next, the configuration of the embodiment shown in the attached drawings will be described. 1 is a plan cross-sectional view of the axle case with the upper half case removed, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2, FIG. 5 is a sectional view taken along the line CC in FIG. 4, FIG. 6 is a sectional view taken along the line DD in FIG. 4, and FIG. 7 is a sectional view taken along the line EE in FIG. 8 is a perspective view of a pump case, and FIG. 9 is a hydraulic circuit diagram.

The axle case includes a half upper case 1 and a half lower case 2, and includes a hydraulic transmission F, an axle 4, and power transmission means for interlocking the two. The vertical dividing line of the axle case is defined by the rotation axis of the hydraulic motor M, the axis of the power transmission shaft (counter shaft) described later, and the axle 4.
Are substantially coincident with a virtual line connecting the axes of the lines. In the hydraulic transmission F, a hydraulic pump P and a hydraulic motor M are mounted on a center section 10 formed in an inverted L-shape in cross section, and the hydraulic pump P is mounted on the upper surface of the center section 10 and the hydraulic pump P is mounted on the side surface of the vertical section. Each of the motors M is mounted.

As shown in FIG. 2, an input shaft 11 as a pump shaft is penetrated substantially at the center of the upper surface of the center section 10 as shown in FIG. 2, and an input pulley is fixed outside the upper half case 1 at the upper end of the input shaft 11. On the center section 10 at the center of the input shaft 11, pistons 22
Are housed outside, and the heads of the pistons 22 abut on the variable swash plate 13,
The angle of the variable swash plate 13 can be changed by rotating an arm 15 fixed to the transmission shaft 14, and the direction and amount of pressure oil discharged from the hydraulic pump P are adjusted to adjust the direction of rotation of the motor shaft 16, The rotation speed can be changed.

The hydraulic motor M has one side of a motor shaft 16 supported at the center of the outer surface of the vertical portion 10a of the center section 10, the other end supported by an axle case, and a brake drum 17 mounted on the outer motor shaft 16. Fixed. A cylinder 25 accommodating pistons 26 is externally fitted to the motor shaft 16.
6 ... The head is in contact with the fixed swash plate.

Then, the cylinder 21 and the cylinder 25
The oil passages 10b and 10c for the discharge oil and the return oil are formed in the center section 10 to communicate between the hydraulic pump P and the hydraulic motor M to form a closed circuit.
Check valves 19a and 19b are fitted into the ends of c, and the check valves 19a and 19b are opened by pressing the release rods 20 and 20, and the pressure in the closed circuit between the hydraulic pump P and the hydraulic motor M is increased. The oil can be drained so that the motor shaft 16 becomes rotatable.
Reference numeral 20 is slid by rotating a release lever 23 provided outside the axle case.

An engraving gear 16a is engraved on the motor shaft 16, and as shown in FIG.
The gear 31 on the counter shaft 30 is meshed with the gear a, and the ring gear 32 of the differential device is meshed with the carved gear 30a carved on the counter shaft 30, and the pair of axles 4 is differentially connected. .

A pump case 7 is affixed to the lower surface of the center section 10, and a pump P1 for replenishing hydraulic oil for the hydraulic transmission F and driving another hydraulic operating device is disposed in the center of the upper surface of the pump case 7. And driven by the input shaft 11. The pump case 7 is formed in a cylindrical shape as shown in FIGS. 3 to 8, and a pump P1 is disposed at the center of the upper surface and attached to the center section 10. The lower half is perpendicular to the split surface of the axle case. In the direction, it penetrates the opening of the half lower case 2 to be exposed to the outside, and the pump case 7 and the half lower case 2 are sealed by interposing an O-ring 33 therebetween.

A filter 24 is provided around the upper half of the pump case 7 located in the lower half case 2,
The suction port 7a of the pump P1 is opened inside the filter 24, and the discharge port of the pump P1 is connected to a line filter 37 via an oil passage 7b, and the line filter 37 is attached to the lower half of the pump case 7. The discharge-side oil passage 7c of the line filter 37 is connected in parallel to a pressure-reducing valve-type replenishing oil pressure setting valve 34, a driving oil pressure setting valve 35, and a resistance valve 36 provided in the pump case 7.

The oil passage (operation port) 7d on the discharge side of the supply oil pressure setting valve 34 is connected to the oil passage 10 of the center section 10.
When the hydraulic oil in the closed circuit of the hydraulic transmission F leaks and the pressure drops, the hydraulic oil adjusted by the supply hydraulic pressure setting valve 34 is connected to the check valve. It is replenished via 19a and 19b. The oil after pressure adjustment is drained into the axle case via an oil passage formed in the pump case.

The drive oil pressure setting valve 35 adjusts the operating oil of another hydraulic operating device. When the pressure exceeds the set pressure, the valve is opened to drain into the axle case. The resistance valve 36 is interposed between the discharge-side oil passage 7c and the hydraulic outlet 38 so that a predetermined pressure oil can be supplied to another hydraulic operating device. As shown in FIGS. 8 and 9, the pump case 7 is opened at an exposed portion and connected to a switching valve 39 via a piping member 42, and a hydraulic cylinder 40 is connected to the switching valve 39 as a hydraulic operating device in this embodiment. doing.

The return oil from the switching valve 39 is connected to a return oil port 41 via a pipe member 43, and the return oil port 4
1 is a reservoir tank 1 provided on the half upper case 1
1, the reservoir tank 1a is provided with a return oil port 41 on the side face as shown in FIG. 1, and a narrow communication port 1b is opened on the lower surface on the other side to communicate with the inside of the axle case. Are provided with guide walls 1c, 1c so that the hydraulic oil flows in a zigzag shape and the flow path becomes long, and when the hydraulic oil mixed with air is returned to the reservoir tank 1a at the initial stage of starting or the like, the communication port is formed. The air is separated in the reservoir tank before returning from 1b to the axle case. 1e is a breather cap.

[0016]

[Effects of the Invention] With the above-described structure, the following effects can be obtained. In other words, the hydraulic pump can be replenished with hydraulic oil and the other hydraulic actuators can be driven by a single pump, so that the number of pumps and the number of parts are reduced, the number of assembly steps is reduced, and the cost is reduced. In addition, the pump oil supply valve and the drive oil pressure setting valve are built in the pump case, which saves space and simplifies the hydraulic circuit configuration, and the centralized valves make maintenance and inspection easy. It became. Further, since the pump case is directly exposed to the outside of the axle case and the hydraulic outlet is located at the exposed portion, piping is also facilitated, and the sealing portion can be minimized.

Further, since the return oil from the other hydraulic operating device is returned to the reservoir tank as described in claim 2, air existing in the piping of the other hydraulic operating device in the initial stage of assembly is transferred to the axle case. As a result, it was difficult to generate air bubbles in the hydraulic oil in the axle case, and the operation of the hydraulic transmission could be stabilized.

[Brief description of the drawings]

FIG. 1 is a plan sectional view showing a state in which a half upper case of an axle case is removed.

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

FIG. 3 is a sectional view taken along the line BB in FIG. 1;

FIG. 4 is an enlarged view of a pump case part in FIG.

FIG. 5 is a sectional view taken along the line CC in FIG. 4;

FIG. 6 is a sectional view taken along the line DD in FIG. 4;

FIG. 7 is a sectional view taken along the line EE in FIG. 4;

FIG. 8 is a perspective view of a pump case.

FIG. 9 is a hydraulic circuit diagram.

[Explanation of symbols]

 F Hydraulic transmission P Hydraulic pump P1 Pump M Hydraulic motor 1 Half upper case 1a Reservoir tank 2 Half lower case 7 Pump case 10 Center section 34 Supply hydraulic pressure setting valve 35 Drive hydraulic pressure setting valve 38 Hydraulic outlet 39 Switching valve 40 Cylinder 41 Return oil port 42/43 Piping member

Claims (2)

(57) [Scope of request for utility model registration] A hydraulic transmission geared to an axle;
A single pump driven by the input shaft of the transmission is provided in the axle case, and the discharge oil from the pump can be supplied for replenishing hydraulic oil for the hydraulic transmission and for driving other hydraulic actuators. In the axle drive device described above, the supply hydraulic pressure setting valve and the drive hydraulic pressure setting valve are housed in the pump case, the discharge port of the pump is connected to the pump port of each valve, and the operation port of the supply hydraulic pressure setting valve is hydraulically shifted. Connected to the hydraulic oil supply circuit of the device, a part of the pump case is penetrated and exposed from the axle case, the working port of the drive oil pressure setting valve is opened on the exposed surface, and another hydraulic operating device is connected via a piping member. An axle drive device connected to the hydraulic circuit of claim 1. 2. An upper portion of the axle case according to claim 1, wherein a reservoir tank which is open through a communication port is provided so that return oil from another hydraulic operating device is returned to the reservoir tank. Features axle drive.