JPH0126882Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a check valve device for a slow return device in a hydraulic device for lifting and lowering a working machine of a tractor.

(B) Prior Art In conventional agricultural tractors, the slow return valve and the stop valve were provided separately, and the operation handles were also provided separately for the slow return operation handle and the stop valve operation handle.

(c) Problems to be solved by the invention The invention consists of a slow return valve and a stop valve, which function as a slow return valve when tightened slightly, and function as a stop valve when tightened further. It is configured as a slow return stop valve.

In addition, the slow return check valve provided in parallel with the slow return stop valve 7 is configured to be compact, and the thickness of the cylinder head 2 is reduced. This is an improved version of the spring receiver.

As a result, the cylinder head, which had traditionally been large, has been made thinner and smaller.

(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.

A slow return stop valve 7 is attached to the cylinder head 2 and is fitted with a slow return throttle land 7a and a stop poppet valve 7b integrally configured. In the configuration in which the slow return check valve 9 is arranged and the two are connected by bypass oil passages 14 and 15, a biasing spring 10 is provided on the rear surface of the ball of the slow return check valve 9 to bias it toward the seat hole B. The biasing spring 1 is brought into direct contact with the
0 extends to the side of the ball of the slow return check valve 9, forming a ball holding part 8a for holding the ball and a ball holding hole 8f, and applying pressure to the ball holding part 8a. An oil hole 8b is drilled, and a flow path gap A is formed between the ball seat hole B and the tip of the ball holding portion 8a.

(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 will be explained.

Fig. 1 is an overall plan view of the hydraulic system, Fig. 2 is a side sectional view, Fig. 3 is an overall hydraulic circuit diagram, and Fig. 4 is an overall plan view of the hydraulic system.
The figure is a side sectional view of the spring receiver 8 on the cylinder head side of the slow return check valve.

The flow of pressure oil will be explained based on the hydraulic circuit diagram in FIG.

A hydraulic pump attached to the tractor engine converts the lubricating oil in the transmission case into pressure oil.
The pressure oil is sent to the hydraulic case 1 via a pipe and reaches the pressure oil external outlet 19 via the pump-side relief valve 33. 33c is a blind plug of the pump-side relief valve 33.

The pressure oil external extraction port 19 is provided on the side surface of the hydraulic case 1, and when there is no need to extract external hydraulic pressure, it is covered with a lid body 25 with a U-shaped detour carved therein, allowing the pressure oil to pass through. Only hydraulic valve 12
flows towards.

Although it is possible to directly screw the extraction plug into the pressure oil external extraction port 19, it is also possible to screw the plug through the pressure oil extraction port 20 equipped with the extraction/non-extraction switching valve 26.

Further, in addition to the take-out/non-take-out switching valve 26, a pressure oil take-out port 21 via a flow rate adjustment valve 27 can be installed to take out the oil.

The pressure oil that has passed through this pressure oil external outlet 19 enters the hydraulic valve 12 and is "raised" by the spool.
It is switched between ``neutral'' and ``lower'', and pressurized oil in the upward direction comes out from the oil passage in the cylinder head 2. It then enters the hydraulic cylinder 1a via the slow return stop valve 7.

Reference numeral 17 denotes a safety valve for releasing the pressure oil in the hydraulic cylinder 1a, which becomes abnormally high pressure when an abnormal force is applied to the working machine.

In FIG. 2, pressurized oil controlled by a hydraulic valve 12 is sent onto an oil path 14.

A slow return stop valve 7, which is an integrated structure of a slow return valve and a stop valve, is interposed.

That is, the gap between the land 7a of the slow return stop valve 7 and the cylinder head 2 constitutes the throttle of the slow return valve.

Further, the gap formed between the poppet valve 7b at the tip of the slow return stop valve 7 and the hole in the cylinder head constitutes a stop valve.

FIG. 2 shows the case where the slow return stop valve 7 is pushed in to enter the stop state.

That is, the pressure oil sent to the oil line 14 is divided into two directions, one side opens the slow return check valve 9, and the other side opens the slow return check valve 9 and passes through the oil line 15 to the stop valve 7.
b, and enters the hydraulic cylinder 1a via the oil passage 16.

The other oil enters the hydraulic cylinder 1a through the gap formed by the slow return land 7a, from the gap in the stop poppet valve 7b, through the oil passage 16, and into the hydraulic cylinder 1a.

Conversely, when the hydraulic valve 12 switches and moves downward, the slow return check valve 9 is pushed by the biasing spring 10 of the spring receiver 8 and pressed against the ball seat hole B, and the pressure returned from the hydraulic cylinder 1a is The oil keeps it closed.

Therefore, the returning oil is returned to the slow return check valve 9.
The oil cannot return through the oil passage 1, and all the returning oil passes through the gap in the land 7a for slow return.
Return to step 4. With this configuration, the size of the gap created by the land 7a adjusts the slow return speed.

In order to adjust the amount of slow return, when the operation handle 3 is turned, the screw rod 6 in the screw body 13 moves back and forth, and the slow return stop valve 7 is finely adjusted and pushed in through the cushioning material 5.

As it is screwed in, the gap between the land 7a for slow return closes first, and then the poppet valve 7b for stop closes completely.

The buffer material 5 is a slow return stop valve 7.
Since the stop valve is integrated with the stop valve like the land 7a, the valve itself moves slightly to the left and right when the hydraulic valve 12 is switched between raising and lowering.
Since collision noise is generated between the screw rod 6 and the screw rod 6, this is provided in order to eliminate this.

The ball of slow return check valve 9 is
During assembly, the cylinder head 2 is inserted from the hydraulic cylinder 1a side and brought into contact with the seat hole B. The biasing spring 10 is brought into direct contact with the rear surface of the ball, and the cylinder head 2 side is
A biasing spring 10 is received by a spring receiver 8.

The spring receiver 8 on the cylinder head 2 side serves as a blind plug for sealing the seat hole B and the insertion hole of the spring receiver 8.

A driver engagement groove 8d is provided in the head of the spring receiver 8 on the side of the hydraulic cylinder 1a, and when the stop pin 28 is applied to the peak 8c of the engagement groove 8d, the spring receiver 8 rotates naturally. It has a rotation stopper to prevent it from loosening. The stop pin 28 is a roll pin fitted into a part of the cylinder head 2.

In order to reduce the size of the slow return check valve 9 itself, the biasing spring 10 is directly applied to the rear surface of the ball of the slow return check valve 9 without providing a spring receiving seat that has conventionally been provided on the rear surface of the ball.

However, if this continues, the balls constituting the slow return check valve 9 will come off the biasing spring and fall, so the ball holding part 8a for holding the balls protrudes from the spring receiver 8, and the ball holding part 8a forms The ball is held by fitting into the ball holding hole 8f.

This prevents the biasing spring 10 from coming off the rear surface of the ball.

However, if the pressure oil in the ball holding hole 8f becomes unable to enter or exit, the movement of the ball becomes slow, so the pressure oil hole 8
b is provided to allow pressurized oil to freely flow in and out of this holding hole 8f.

Furthermore, if the tip of the holding portion 8a comes too close to the seat hole B of the ball, a restriction will occur at this portion, so a sufficient flow path gap A is formed by a funnel-shaped slope.

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

First, the slow return valve and stop valve were integrated, and when tightened a little, it worked as a slow return valve, and when tightened further, it worked as a stop valve. This eliminates the need to provide separate cylinder heads, reducing the number of man-hours required for processing and assembling the cylinder head.

Second, the spring receiver provided at the rear of the ball constituting the slow return check valve 9 is omitted, and the biasing spring 10 is brought into direct contact with the rear surface of the ball, allowing the slow return check valve 9 to be shortened. The structure is easy to assemble and process.

In addition, in a configuration in which the biasing spring 10 is in direct contact with the ball, there is a possibility that the biasing spring 10 will come off the ball. This problem could be solved by holding the ball in place.

Furthermore, when a ball is inserted into the ball holding hole 8f, if the pressure oil in the ball holding hole 8f cannot go in and out, the movement of the ball may become slow. By providing this, the pressure oil can freely flow in and out of the holding hole 8f, thereby solving the problem.

This allows the slow return stop valve 7 to be removed without increasing the thickness of the cylinder head 2.
This makes it possible to arrange a slow return check valve 9.

[Brief explanation of the drawing]

Fig. 1 is an overall plan view of the hydraulic system, Fig. 2 is a side sectional view, Fig. 3 is an overall hydraulic circuit diagram, and Fig. 4 is an overall plan view of the hydraulic system.
The figure is a side sectional view of the spring receiver of the check valve. A...Flow path gap, B...Ball seat hole, 7...
Slow return stop valve, 8... Spring receiver, 8a... Holding part, 8b... Pressure oil hole, 8f...
Ball holding hole, 9...Slow return check valve, 14, 15...Detour oil path.

Claims (1)

[Scope of utility model registration request] A slow return stop valve 7 is attached to the cylinder head 2 and is fitted with a slow return throttle land 7a and a stop poppet valve 7b integrally configured. In the configuration in which the slow return check valve 9 is arranged and the two are connected by detour oil passages 14 and 15, a biasing spring 10 is provided on the rear surface of the ball of the slow return check valve 9 to bias it toward the seat hole B. The biasing spring 1 is brought into direct contact with the
0 extends to the side of the ball of the slow return check valve 9, forming a ball holding part 8a for holding the ball and a ball holding hole 8f, and applying pressure to the ball holding part 8a. A hydraulic system for an agricultural tractor, characterized in that an oil hole 8b is bored and a flow path gap A is formed between the ball seat hole B and the tip of the ball holding part 8a.