JPH0331076A - tractor hydraulic system - Google Patents

Abstract

PURPOSE:To perform work, not influenced by fluctuation of a hydraulic load, by providing a three-point link compensation valve means, which preferentially feeds pressure fluid to a control valve means for a three-point link hydraulic device further feeds a residual amount to an auxiliary control valve means, in a feed fluid circuit of an oil hydraulic pump. CONSTITUTION:This hydraulic system has a control valve means 17 for a three- point link hydraulic device 9, mounted to the car body rear part of a tractor 1, and auxiliary control valve means 23, 24 for hydraulic cylinders 28, 29 which drive a work machine. While this hydraulic system is provided with a three-point link compensating valve means 22. This compensating valve means 22 is constituted of a throttle valve 25, provided in a feed fluid circuit 15 of a pump 13 so as to preferentially feed pressure fluid to the three-point link control valve means 17 further to enable the residual amount to be fed to the auxiliary control valve means 23, 24, and a control spring 26-provided relief valve 27 or the like actuated by a pilot pressure. When the pilot pressure of the residual amount from the throttle valve 25 overcomes the control spring 26, the fluid is controlled to be fed to the auxiliary control valve means 23, 24.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a hydraulic system for a tractor.

(Conventional technology) Hydraulic pressure is used in the tractor's own power steering, brakes,
It is used not only for three-point links, but also for driving front loaders and various types of work equipment with hydraulic motors, and remote control using hydraulic cylinders. For this reason, some modern tractors have several hydraulic outlet ports. This is because when power is transmitted from the PTo shaft, the transmission device becomes complicated, but when using hydraulic pressure, hoses have a high degree of freedom and power can be transmitted easily. This is because it is absorbed by the action of relief valves, etc. (New Edition Agricultural Machinery Handbook No. 3)
See page 31; Publisher (Ko Coronasha).

(Problem to be solved by the invention) By the way, as the need for more complex agricultural work increases, there are demands for front three-point links, rear three-point links, abdominal mounting, etc., and if these can be controlled hydraulically. It's advantageous.

However, in the prior art, it is difficult to simultaneously operate the rear three-point link and the auxiliary control valve means from the hydraulic outlet, making it difficult to adapt to the complex nature of agricultural work.

Furthermore, even if multiple hydraulic outlets are provided to complicate work, if there are fluctuations in the hydraulic load from both outlets, the load pressure will be affected and the work will not be equalized. There was also.

The present invention provides a plurality of hydraulic outlet ports separately from the three-point linkage hydraulic system and operates the same with an auxiliary control valve means to adapt to complex agricultural work. To provide a hydraulic system that can be controlled under any conditions, while being unaffected by fluctuations in load pressure when performing multiple operations controlled by auxiliary control valve means. The purpose is to

(Means for Solving the Problems) The present invention comprises a control valve means for a three-point linkage hydraulic system and an auxiliary control valve means for hydraulic work, and a hydraulic pressure system for sending hydraulic pressure to the re-control valve means. In the hydraulic system of a tractor equipped with a pump, the following technical measures are taken to achieve the aforementioned objective.

That is, the present invention provides the liquid feeding circuit 1 of the hydraulic pump 13.
5, control valve means 17 for the three-point linkage hydraulic system 9;
The auxiliary control valve means 2324 is provided with a three-point link compensation valve means 22 for preferentially sending hydraulic pressure to the hydraulic pressure and sending the remaining amount to the auxiliary control valve means 23, 24, and furthermore, the auxiliary control valve means 2324 are plural. , a flow control valve 34.35 is provided for distributing the remaining amount to each auxiliary control valve means 23.24.

(Function) According to the present invention, Cane Cutter is installed in the front three-point link of the tractor, Sweeper is installed in the abdomen of the tractor, and Mower is installed in the rear three-point link of the tractor. When carrying out complex work with each of the
Since hydraulic pressure is preferentially sent to the control valve means 17 by the point link compensation valve means 22, control can be performed regardless of front or mid work.

On the other hand, the remaining amount of hydraulic pressure from the three-point link compensation valve means 22 is sent to the auxiliary control valve means 23.24, so that the work by the Ken cutter and the swivel is guaranteed. Even if there is, it is distributed by the flow control valves 34 and 35, so it is not a problem.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows a tractor 1, which is a two-axle, four-wheel type having a front wheel 2 and a rear wheel 3, and the front wheel 2 is
It can be driven by a propulsion shaft device 4 and is also a four-wheel drive type.

Reference numeral 5 denotes an engine, which is interlocked with a transmission 6.7 via a main clutch, and the transmissions 6 and 7 are built into the vehicle body 8.

Reference numeral 9 denotes a three-point linkage hydraulic system, which includes a hydraulic cylinder and a piston, has a pair of left and right lift arms 10, and is mounted on the rear of the vehicle body 8.

In FIG. 2, reference numeral 11 indicates a control handle, and reference numeral 12 indicates a driver's seat. Although not shown, the tractor I can be equipped with a front three-point link, a mint link, etc.

Therefore, this tractor 1 can be equipped with a Ken cutter on the front, a rider on the middle, and a culture or a duster on the rear, or a culture or duster on the front, a rider on the middle, a sprayer, etc. on the rear. You can change your working style.

Referring to FIG. 1, the hydraulic system of the tractor 1 described above is illustrated.

In FIG. 1, 13 is a hydraulic pump, and engine 5
In this example, it is a variable discharge amount pump (load sensitive control).

A flow priority valve 14 is provided in the liquid feeding circuit 15 of the hydraulic pump 13, and is connected to the hydraulic circuit of the power steering device 16 in this embodiment.

Reference numeral 17 denotes a control valve means for the three-point linkage hydraulic system 9, which controls the piston 9B fitted into the cylinder 98 in the hydraulic system 9.

For this purpose, the control valve means 17 includes a switching valve 18, a check valve 19 with a throttle valve, a check valve 20, a relief valve 21 operated by pilot pressure, and the like.

Reference numeral 22 denotes a three-point link compensation valve means, which controls the pump 13 to send hydraulic pressure preferentially to the three-point link control valve means 17 and the remaining amount to the auxiliary control valve means 23 and 24. It is provided in the liquid circuit I5.

Therefore, the compensation valve means 22 includes a throttle valve 25 and a relief valve 2 with a control spring 2G operated by pilot pressure.
7, etc., and when the remaining pilot pressure from the throttle valve 25 overcomes the control spring 26, the auxiliary control valve means 23.
The liquid is sent to 24.

Auxiliary side? Two IB valve means 23, 24 are provided in this embodiment, and each is provided with a switching valve 32, 33 to control a piston 30, 31 fitted in a hydraulic cylinder 28, 29. On the inlet side of the switching valves 32 and 33,
Flow control valves 34, 35 are provided for distribution to each valve means 23,24.

Each flow control valve 34, 35 consists of a relief valve 38, 39 with a control spring 36, 37 operated by pilot pressure.

The above-mentioned relief valves 27, 38, and 39 each have an anti-saturation section, which means that even if the pump discharge amount is less than the valve control flow rate, the valve control flow rate is reduced by the operation of the anti-saturation section. Cover the shortfall in flow rate.

In addition, 40, 41, and 42 are check valves for feeding back the load pressure to the pump 13, and are intended to reduce energy loss in both pressure and flow rate.

Further, the hydraulic cylinders 28, 29 and the hydraulic pistons 30, 31, which are controlled by the hydraulic pressure from the hydraulic pressure outlet, may be a hydraulic motor or a hydraulic pump, and the equipment hydraulically driven by the working machine is different. Further, in FIG. 1, 43 is a filter, 44 is a tank, and 45 is a power steering cylinder.

(Effects of the Invention) The present invention is as described above, and according to the present invention, hydraulic pressure is applied in advance to the control valve means for the three-point linkage hydraulic device in the liquid feeding circuit of the hydraulic pump. and a three-point link compensation valve means for sending the liquid to the auxiliary control valve means and the remaining amount to the auxiliary control valve means,
Furthermore, the 1111 auxiliary control valve means is plural,
Since it is equipped with a flow control valve that distributes the remaining amount to each auxiliary control valve means, the three-point linkage hydraulic system can be operated under any conditions, and a plurality of auxiliary control valve means can be operated. In this case, if the pump discharge amount (residual amount from the compensation valve means) is the valve required flow rate, the pressure compensation at the valve inlet with lower load pressure can be throttled down and oil can also flow to the high pressure side. It can be made less susceptible to the influence of load pressure.

Therefore, the hydraulic system of the present invention is useful for carrying out complex operations by mounting various hydraulic working devices on the front, rear, middle, etc.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a circuit diagram of a hydraulic system, and FIG. 2 is a side view of a tractor. l...Tractor, 9...3-point link hydraulic system, 1
3...Hydraulic pump, 15...Liquid feeding circuit, 17...
Control valve means, 22...Compensation valve means, 23.24...
Auxiliary control valve means, 34°35...Flow rate control valve. Procedural amendment (procedural amendment) August 22, 1999

Claims (1)

[Claims] (1) A tractor hydraulic system comprising a control valve means for a three-point linkage hydraulic system and an auxiliary control valve means for hydraulic work, and a hydraulic pump for delivering hydraulic pressure to both the control valve means, The liquid feeding circuit (15) of the hydraulic pump (13) is configured to preferentially feed hydraulic pressure to the control valve means (17) for the three-point linkage hydraulic system (9) and to supplementally control the remaining amount. Valve means (
23) Three-point link compensation valve means (22) for sending liquid to (24)
), further comprising the auxiliary control valve means (23) (24).
is set to be plural, and the remaining amount is determined by each auxiliary control valve means (2
3) A hydraulic system for a tractor, characterized in that it is equipped with flow control valves (34) and (35) for distributing flow to (24).