JPH0249108Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a hydraulic steering device for a low-horsepower four-wheel running wheel such as a riding rice transplanter that travels through the mud of a paddy field.

(b) Prior Art A hydraulic steering system in a conventional four-wheeled vehicle was constructed as shown in FIG.

That is, pressure oil is discharged by a hydraulic pump P driven by an engine E, and the pressure oil from the hydraulic pump P passes through a relief valve R and then is sent to a flow divider B. The flow rate was divided into two parts, and one part was sent to the hydraulic control valve A of the steering hydraulic system, and the other part was sent to the hydraulic control valve V of the work machine lifting system.

In such a conventional configuration, the hydraulic pump P required a large capacity, and could not be used as a hydraulic system for a low horsepower working machine.

Furthermore, as another conventional technique, a technique such as that disclosed in Japanese Unexamined Patent Publication No. 102744/1983 is known as a hydraulic steering system for automobiles.

(c) Problems that the invention aims to solve is divided into two directions by flow control valve C, and the oil sent by the hydraulic steering device is merged in front of the hydraulic device for lifting and lowering the work equipment.
This allows operation with a small hydraulic pump.

In addition, the arrangement of the hydraulic control valve A of the steering hydraulic system and the hydraulic cylinder 8 is reversed from left to right with respect to the aircraft, eliminating play in the link, improving valve responsiveness, and preventing shimmy. It is something.

(d) Means for solving the problem The purpose of the present invention is as described above. Next, the configuration for achieving the purpose will be explained.

The suction valve 12, the relief valve 15 and the flow control valve C are connected to the hydraulic pump P.
The hydraulic system for steering and the hydraulic system for lifting and lowering the work equipment are arranged in parallel between the high-pressure oil passage from the hydraulic control valve A to the hydraulic system for lifting and lowering the work equipment, and the oil passage from the hydraulic control valve A to the hydraulic system for lifting and lowering the work equipment. are arranged in series, and both can be operated simultaneously by one hydraulic pump P. A hydraulic control valve A of the steering hydraulic system is interposed between the Knuckle arm 5 and the Pittman arm 3, and the steering hydraulic cylinder 8 is interposed between the fuselage and the knuckle arm 5, and both are arranged separately on the left and right sides of the fuselage.

(e) Embodiment The purpose and structure of the present invention are as described above. Next, the structure of the embodiment shown in the attached drawings and the operation of the invention will be explained.

Fig. 1 is an overall side view of a riding rice transplanter, Fig. 2 is a hydraulic circuit diagram of the hydraulic steering device of the present invention, Fig. 3 is a hydraulic circuit diagram of a conventional hydraulic steering device, and Fig. 4 is a hydraulic circuit diagram of the hydraulic steering device of the present invention. A plan view of the hydraulic steering device of the present invention, and FIG. 5 is a plan view of a conventional hydraulic steering device.

Referring to FIG. 1, the configuration of a riding rice transplanter will be explained.

The front wheels are steering wheels 1, and the rear wheels are drive wheels 19. A planting device is disposed as a working machine D at the rear end of the machine. The hydraulic system for lifting and lowering the work machine moves the work machine D, which is the planting device, up and down.

In addition, the steering handle 2 is used to rotate the Pitman arm 3 back and forth, and the hydraulic control valve A is operated to expand and contract the hydraulic cylinder 8, thereby rotating the bell crank 4 and rotating the Knuckle arms 5L and 5R. The steering wheel 1 is rotated to steer the steering wheel 1. 50 is the front axle case, 16
is the body of a riding rice transplanter.

Next, the arrangement of the hydraulic control valve A and the hydraulic cylinder 8 will be explained with reference to FIGS. 4 and 5.

Conventionally, as shown in FIG. 5, a hydraulic control valve A and a hydraulic cylinder 8 are arranged on one side of the fuselage 16, in the embodiment, on the left side in the direction of travel, and both are connected by a bell crank 4. The tie rod 6 was extended out and connected to the left and right knuckle arms 5L and 5R.

However, in this conventional configuration, the left side of the fuselage had a complicated configuration, and the piping 7 was also difficult to install.

In the present invention, the hydraulic control valve A and the hydraulic cylinder 8 are placed in separate positions on the left and right sides of the aircraft, and the conventional bell crank 4 is also abolished, and the hydraulic control valve A and the hydraulic cylinder 8 are directly connected. It is connected to the knuckle arms 5L and 5R.

This makes it possible to eliminate the bell crank 4, eliminate play in the link, and improve the responsiveness of the hydraulic control valve A.

Further, in contrast to FIG. 3, which shows the hydraulic circuit of a conventional steering hydraulic system, the present invention is constructed as shown in FIG. 2. That is, a steering hydraulic system and a working machine lifting hydraulic system are arranged in series in a hydraulic circuit from a hydraulic pump P. The steering hydraulic system is composed of a hydraulic control valve A, a suction valve 12, a relief valve 15, a flow control valve C, etc., and these components are arranged in parallel.

That is, the suction valve 12, the relief valve 15, and the flow control valve C are installed between the high-pressure oil path from the hydraulic pump P to the hydraulic control valve A, and the oil path from the hydraulic control valve A to the hydraulic system for lifting and lowering the work machine.
They are arranged in parallel.

After oil is sent to the hydraulic cylinder 8 via the hydraulic control valve A, the relief valve 15
After the is fully rotated, the hydraulic control valve A is in a state other than the neutral position and there is no place for the pressure oil to go.In this case, the relief valve 15 is opened and the pressure oil is transferred to the hydraulic control valve V for lifting and lowering the work equipment. It flows in the direction of. Further, when the hydraulic control valve A is in the neutral position, the pressure oil flows from the neutral port of the hydraulic control valve A to the hydraulic control valve V for lifting and lowering the working machine without passing through the relief valve 15.

The suction valve 12 is designed so that when the speed at which the operator pushes and pulls the drag rod is faster than the expansion and contraction speed of the hydraulic cylinder 8, the inside of the hydraulic cylinder 8 will not become a vacuum and cavitation will not occur. 12 opens to allow both the expanding and contracting oil chambers of the hydraulic cylinder 8 to communicate with each other. The suction valve 12 also plays an important role when the operator performs manual steering when the hydraulic pump P is stopped and no pressure oil is generated.

That is, if there is no suction valve 12,
Steering handle 2 when hydraulic pump P stops
If the tire is rotated, one side of the hydraulic cylinder will have negative pressure and the tire will return to its original position.

Furthermore, manual steering is possible because the hydraulic control valve A is interposed between the pitman arm 3 and the knuckle arms 5L and 5R.

In the above configuration, the present invention further includes:
A flow control valve C is inserted in parallel. The flow control valve C is capable of sending a constant flow of oil to the hydraulic control valve A, and at the same time is capable of sending the remaining oil to the hydraulic control valve V for lifting and lowering the working machine.

(f) Effects of the invention Since the invention is constructed as described above, it has the following effects.

First, since the flow control valve C is installed, a constant flow rate can always be sent to the hydraulic control valve A of the steering hydraulic system even when the engine E is idling or at maximum rotation. This has the advantage that the steering feel does not change. In addition, by sending the remaining oil to the hydraulic system for lifting and lowering the work equipment and combining it with the oil at the destination,
With the conventional system, the flow was taken up by the steering hydraulic system when the machine was idling, resulting in less pressure oil in the hydraulic system for lifting and lowering the work equipment, which slowed down the lifting speed of the work equipment. , we were able to improve this point.

Second, since the suction valve 12 is installed, when the speed at which the operator pushes and pulls the drag rod is faster than the speed at which the hydraulic cylinder 8 expands and contracts, the inside of the hydraulic cylinder 8 becomes a vacuum.
When cavitation occurs, the suction valve 12 opens to allow both the expansion and contraction oil chambers of the hydraulic cylinder 8 to communicate with each other.

Further, the suction valve 12 is connected to a hydraulic pump P.
Even when the operator manually steers the engine when the engine is stopped and no pressure oil is generated, the system is designed to prevent a vacuum from occurring.

Thirdly, because the hydraulic control valve A and the hydraulic cylinder 8 are placed on opposite sides of the aircraft, the link structure is simplified, there is less play in the link, and the responsiveness of the hydraulic control valve A is improved. It is possible to prevent this from occurring and improve the steering feel.

[Brief explanation of the drawing]

Figure 1 is an overall side view of a riding rice transplanter, Figure 2 is a hydraulic circuit diagram of the steering hydraulic system of the present invention, Figure 3 is a hydraulic circuit diagram of a conventional steering hydraulic system, and Figure 4 is a hydraulic circuit diagram of a conventional steering hydraulic system. A plan view of the steering hydraulic system of the present invention, and FIG. 5 is a plan view of a conventional steering hydraulic system. A... Hydraulic control valve, C... Flow control valve, V... Hydraulic control valve for lifting and lowering work equipment, 2...
Steering handle, 8...hydraulic cylinder,
9... Hydraulic cylinder for lifting and lowering the work machine, 12... Suction valve, 15... Relief valve.

Claims (1)

[Scope of utility model registration request] The suction valve 12, the relief valve 15 and the flow control valve C are connected to the hydraulic pump P.
The hydraulic system for steering and the hydraulic system for lifting and lowering the work equipment are arranged in parallel between the high-pressure oil passage from the hydraulic control valve A to the hydraulic system for lifting and lowering the work equipment, and the oil passage from the hydraulic control valve A to the hydraulic system for lifting and lowering the work equipment. are arranged in series, and both can be operated simultaneously by one hydraulic pump P. A hydraulic control valve A of the steering hydraulic system is interposed between the Knuckle arm 5 and the Pittman arm 3, and the steering hydraulic cylinder 8 is interposed between the fuselage and the knuckle arm 5, and both are arranged separately on the left and right sides of the fuselage.