JPH0466739B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a wet disc brake mechanism on a differential shaft protruding left and right from a rear wheel differential mechanism, and a control valve for lifting and lowering a working device is installed at the rear wheel differential mechanism. The present invention relates to a transmission case structure for a working vehicle, which is disposed above a wheel differential mechanism and configured to directly return waste oil from a control valve into the transmission case.

[Prior Art] In a construction in which a work vehicle such as an agricultural tractor is equipped with a wet disc brake mechanism as described above, the brake case that covers the disc brake mechanism and the transmission case are communicated, and the lubricating oil in the transmission case is used to It lubricates and cools the disc brake.

[Problem that the invention seeks to solve]

Lubricating oil inevitably stays on the bottom side of the brake case, and no matter how much the brake disc of the disc brake mechanism rotates, the bottom side of the brake case of the disc brake mechanism, that is, soaked in lubricating oil. Areas near the area will be primarily lubricated and cooled. In comparison, the lubricating oil does not reach the upper part of the disc brake mechanism so much that sufficient lubrication and cooling may not be achieved.

The present invention focuses on the above-mentioned problem and aims to provide a mechanism with a simple structure that can sufficiently lubricate and cool the entire disc brake mechanism.

[Means for solving problems]

The feature of the present invention is that the transmission case structure for a work vehicle as described above is configured as follows.

A receiving portion for receiving a portion of the drained oil from the control valve is provided in the transmission case on the opposite side of the brake disc of the disc brake mechanism from the piston member for braking operation, and a receiving portion for receiving a portion of the drained oil in the receiving portion is provided. In the upper part of the disc brake mechanism, a guide path is provided which supplies a portion of the brake disc opposite to the piston member.

[Effect]

For work vehicles, such as agricultural tractors, in which working devices such as rotary tillers are attached to the machine body using hydraulic pressure so that they can be raised and lowered, lubricating oil in the transmission case is used as hydraulic oil for raising and lowering operations. Many models are configured to return hydraulic fluid directly from the control valve into the transmission case.

Therefore, when configured as described above, for example, as shown in FIG.
It is supplied to the upper part of the disc brake mechanism through the guide path 24. This ensures that not only the lower part of the disc brake mechanism but also the upper part is sufficiently lubricated and cooled.

In the case of a disc brake mechanism mainly composed of a brake disc and a piston member, the portion of the brake disc that the piston member contacts and presses is heated the most.

Therefore, for example, as shown in FIG. 1, if lubricating oil is supplied to the part of the brake disc 10 facing away from the piston member 13 for braking operation in the upper part of the disc brake mechanism, the piston member will come into contact and press. Since lubricating oil is directly supplied to the parts of the brake disc that are heated the most, this part can be cooled quickly.

〔Effect of the invention〕

As mentioned above, some of the oil returned from the control valve is
By supplying the lubricating oil to the upper part of the disc brake mechanism, the lubricating oil is sufficiently distributed throughout the disc brake mechanism, making it possible to prevent heat generation, seizure, etc. due to lack of partial lubricant cooling.

Since the lubricating oil is directly supplied to the most heated part of the brake disc, this part is quickly and efficiently cooled, making it possible to better prevent local heat generation and seizure.

[Example] Hereinafter, an example of the present invention will be described based on the drawings.

Figure 3 shows a side view of the rear half of an agricultural tractor, which is an example of a working vehicle. Tillage device 18
A lift arm 20 is connected to the rear of the aircraft and is swing-driven by a single-acting hydraulic cylinder 19.
The rotary tiller 18 is connected to the lower link 17 via a rod 21 so that the rotary tiller 18 can be moved up and down with respect to the machine body.

The lubricating oil in the transmission case 1 is supplied to the hydraulic cylinder 19 via a filter and a pump (not shown) through an electromagnetic three-position mist exchange type control valve 22.
Pressure oil is supplied from the control valve 22, the hydraulic cylinder 19 is extended, and the rotary tiller 18 is raised. Conversely, the control valve 22
When the is operated to the oil drain side, the hydraulic oil in the hydraulic cylinder 19, that is, the lubricating oil, is returned directly from the hydraulic cylinder 19 to the mission case 1 via the control valve 22, and the rotary tiller 18 is moved by its own weight. Go down. At this time, the discharged oil from the control valve 22 is spread over a relatively wide area within the mission case 1 due to the discharge pressure from the hydraulic cylinder 19 due to the descending action of the rotary tiller 18, and is injected from the control valve 22. It will be returned as such.

Next, to explain in detail the structure near the rear wheel differential mechanism 2 of the transmission case 1, as shown in FIG. 1, the rear wheel differential mechanism 2 is arranged inside the transmission case 1, and The differential shaft 3 protrudes from. This rear wheel differential mechanism 2 is supported via a case support 14.
4 is connected to the mission case 1 inside a recess formed on the outer surface 1a of the mission case 1.

A shift member 4 for a differential lock is spline-fitted to the differential shaft 3, and the shift member 4, which is biased toward the cutting side by a spring 15, is slid in the axial direction by a shifter 5 to move the differential shaft 3 to the differential shaft 3. By engaging 2a, the deflock operation is performed.

A brake case 6 and an axle case 7 are connected to the side surface of the transmission case 1, and power from the differential shaft 3 is transmitted to an axle 9 via a planetary reduction mechanism 8 to drive rear wheels (not shown).

Next, the wet disc brake structure housed in the brake case 6 will be described in detail.
As shown in the figure, there is a brake disc 1 on the differential shaft 3.
0 are spline-fitted, and a ring-shaped plate 11 is sandwiched between the brake discs 10 and fitted inside the brake case 6. Notches are provided at multiple locations on the outer periphery of the plate 11, and the notches are engaged with locking pins 12 arranged at multiple locations within the brake case 6, thereby controlling the rotation of the differential shaft 3 and the brake disc 10. Accordingly, the structure is such that the plate 11 does not rotate together.

Next, the structure of the ring-shaped piston member 13 that presses the brake disc 10 and plate 11 toward the transmission case 1 will be described in detail.
In the brake case 6, a first inner circumferential surface 6a and a second inner circumferential surface 6b having a larger diameter are provided concentrically to form a stepped portion. Then, the piston member 13 is provided with a step-shaped outer circumferential surface that is in sliding contact with the first and second inner circumferential surfaces 6a and 6b, and this is attached to the brake case 6.
The locking pin 1 is fitted into the locking pin 1 in an oil-tight manner, and the notches provided at multiple locations on the outer periphery of the piston member 13 are
2 is involved.

Then, operating pressure oil is fed into an annular piston driving oil chamber S formed between the step between the first and second inner circumferential surfaces 6a and 6b of the brake case 6 and the piston member 13. , the piston member 13 is slidably driven to press the brake disc 10 and plate 11 against the outer surface 1a of the transmission case 1 to perform braking.

As shown in the figure, a partial gutter-shaped receiving part 23 is provided in the transmission case 1 on the inner wall of the transmission case 1 on both sides of the rear wheel differential mechanism 2, and a piston member 13 is provided in the upper part of the brake disc 10. is the brake disc 1 facing the opposite side
A guide path 2 that communicates the 0 part with the receiving part 23
There are 4. As a result, a part of the drained oil from the control valve 22 is supplied to the receiving portion 23 via the receiving guide path 24 to the portion of the brake disc 10 facing on the opposite side from the piston member 13. There is. Furthermore, as shown in FIG. 2, the upper and lower sides of the plates 11 are cut out horizontally, so that the drained oil from the guide path 24 and the lubricating oil in the Mitsuihon case 1 can be distributed to each plate 11 and each brake disc 10. It is structured in such a way that it spreads easily.

[Brief explanation of drawings]

The drawings show an embodiment of the transmission case structure of a working vehicle according to the present invention, in which Fig. 1 is a longitudinal sectional front view of the vicinity of the rear wheel differential mechanism, Fig. 2 is a front view of the plate and brake disc, and Fig. 3 is an agricultural vehicle. FIG. 3 is a side view of the rear half of the tractor. 1...Mission case, 2...Rear wheel differential mechanism, 3...Differential shaft, 10...Brake disc,
13... Piston member, 22... Control valve, 23...
...Reception part, 24...Guidance path.

Claims (1)

[Claims] 1 Differential shaft 3 protruding left and right from the rear wheel differential mechanism 2
In addition to installing a wet disc brake mechanism,
A working vehicle is constructed in which a control valve 22 for lifting and lowering the working equipment is arranged above the rear wheel differential mechanism 2, and drained oil from the control valve 22 is directly returned from the control valve 22 into the mission case 1. The transmission case has a structure in which a receiving portion 23 for receiving a portion of the drained oil from the control valve 22 is connected to a piston for braking operation with respect to the brake disc 10 of the disc brake mechanism within the transmission case 1. Provided on the opposite side to the member 13, and the receiving portion 23
A transmission case structure for a working vehicle, which is provided with a guide path 24 for supplying waste oil inside the brake disc 10 to a portion of the brake disc 10 opposite to the piston member 13 in the upper part of the disc brake mechanism.