JPH0452550Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a direct acting relief valve, and in particular to surge pressure suppression technology, for example, for controlling medium pressure (approximately 100 kg/cm ² ). Concerning what is effective when used for something.

[Conventional technology]

Generally, in a direct acting relief valve, when the set pressure becomes high, a chattering phenomenon occurs, causing a problem of pulsation in the internal pressure of the pipe on the upstream side of the direct acting relief valve.

Therefore, when the set pressure is medium or higher, direct acting relief valves such as those shown in FIGS. 4 and 5, for example, are used to prevent the chattering phenomenon.

That is, the direct-acting relief valve shown in FIG. 4 includes a fixed valve 3 fixed to an inlet port 2 of a body 1, and a movable seat 4 slidably fitted to the fixed valve 3. A damping chamber 5 is formed inside the movable seat 4 so as to be sealed by a fixed valve 3, and the volume of the damping chamber 5 is relatively increased or decreased by the fixed valve 3. The vibration of the movable seat 4 is damped by increasing and decreasing the volume of the damping chamber 5 when the movable seat 4 opens and closes the valve. It is composed of

The direct-acting type relief valve shown in FIG. 5 is equipped with a sealed damping chamber 8 disposed at the front of the poppet 7 on the seating side. The structure is such that vibrations are attenuated by increasing and decreasing the volume of the bar 8.

[The problem that the idea aims to solve]

In such direct-acting relief valves, both damping chambers are sealed, so
Due to the delay in lifting the movable seat and poppet,
There is a problem in that the surge pressure on the upstream side of the direct acting type relief valve appears larger than the set pressure, as shown in FIG.

An object of the present invention is to provide a direct-acting relief valve that can prevent chattering while suppressing surge pressure.

[Means to solve the problem]

A direct-acting relief valve according to the present invention is a direct-acting relief valve that is equipped with a damping chamber configured to vary its volume following the opening and closing operations of a valve body. A check valve is provided, the check valve being configured to open the damping chamber when the valve body moves in the opening direction and close the damping chamber when the valve body moves in the closing direction. It is characterized by the presence of

[Effect]

According to the above-described means, when the valve body moves in the opening direction, the damping chamber is brought into an open state by the check valve, so that the valve body opens with good responsiveness. Therefore, the surge pressure in this direct acting relief valve is suppressed to a small level.

On the other hand, when the valve body moves in the closing direction, the damping chamber is sealed by the check valve, and therefore exhibits a damper effect. Therefore, the chattering phenomenon is prevented.

〔Example〕

FIG. 1 is a vertical sectional view showing a direct acting relief valve which is an embodiment of the present invention, and FIGS. 2 and 3 are diagrams for explaining the effects thereof.

In this embodiment, the direct acting relief valve according to the present invention includes a body 11 in which a hollow portion 12 is formed, and the body 11 has an inlet passage 13 and an outlet passage 14 communicating with the hollow portion 12. It was opened in . A valve cylinder 16 is screwed into the hollow part 12 of the body 11 from an opening at one end, and an O-ring 15 is interposed between the outer periphery of the valve cylinder 16 and the inner periphery of the hollow part 12. The valve cylinder 16 has a valve chamber 17
are arranged concentrically, and a valve seat 18 is formed in the hollow part of the valve chamber 16 so as to surround the valve port. In addition, the valve cylinder 16 has an inlet port 19.
And outlet ports 20 are arranged on both sides of the valve seat 18 and are opened so as to communicate the valve chamber 16 and the hollow portion 12. A poppet valve 21 as a valve body is housed in the valve chamber 17 and is arranged so as to be able to sit on and off from the valve seat 18, and the poppet 21 is always urged in the seating direction by a pressure adjustment spring 22. ing. Pressure adjustment spring 2
2 has its biasing force adjusted by an adjustment screw member 23 screwed into the valve cylinder 16,
The adjusting screw member 23 is adapted to be locked in its adjusted position by a lock nut 24.

A damping chamber 25 is provided at the end of the valve chamber 17 opposite to the adjustment spring 22.
A piston 26 is fitted into the damping chamber 25 so as to be slidable in the axial direction. The piston 26 is connected to the poppet 21 by a valve stem 27 so as to move integrally therewith.

A check valve 28 is provided at the tip of the valve cylinder 16 forming the damping chamber 25 .
That is, a valve port 29 is arranged on the axis of the tip wall of the valve cylinder 16 and is opened so as to communicate between the hollow part 12 and the damping chamber 25. A valve seat 30 is formed. A ball 31 serving as a valve body of the check valve 28 is housed in the damping chamber 25 so as to be seated on and off the valve seat 30 . 32, the seat is always biased in the seating direction.

Next, the action will be explained.

Normally, the poppet 21 of the direct-acting relief valve having the above configuration is pressed against the valve seat 18 by the urging force of the pressure adjustment spring 22, so that pressure oil is prevented from flowing from the inlet port 19 toward the outlet port 20. It is blocked.

When the pressure in the hydraulic circuit (not shown) to which this direct-acting relief valve is connected increases and the force pushing up the poppet 18 becomes greater than the set force of the spring 22, the poppet 21 moves away from the valve seat 18. To leave, the pressure oil returns to the oil tank (not shown) through the inlet passage 13 -> inlet port 19 -> valve port -> outlet port 20 -> outlet passage 14 and the pressure in the circuit is released.

When the pressure in the hydraulic circuit falls below the set force of the pressure adjustment spring 22, the poppet 21 is returned to its original position by the biasing force of the spring 22, so that the return of pressure oil is stopped.

In this relief operation, when the poppet 21 moves in the direction of unseating, the ball 31 is unseated from the valve seat 30 due to the pressure acting from the direction of the valve port 29, so the damping chamber 25 is in an open state. . Therefore, the damping chamber 25
Since the valve is no longer acting as a damper, the poppet 21 will move away from the valve seat 18 very quickly. In other words, since the operational response delay of the poppet 21 is short, as shown in FIG. 2, the third pressure is suppressed to be smaller than in the conventional example shown in FIG. 3.

On the other hand, when the poppet 21 moves in the direction of seating,
Since the ball 31 is seated on the valve seat 30, the damping chamber 25 is in a sealed state. Therefore, the damping chamber 25 is in a state where it performs a damping effect, so that the poppet 21 is prevented from chattering. By preventing the chattering phenomenon, noise is prevented, and the occurrence of pulsation in the hydraulic circuit to which this direct acting relief valve is connected is also prevented.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be modified without departing from the gist thereof.
It goes without saying that various changes are possible.

For example, poppet 21, valve stem 27 and piston 26 may be formed in one piece. Further, the damping chamber is not limited to being formed at the bottom of the valve cylinder, but may be formed between the fixed valve and the movable seat.

Check valves are not limited to using balls as the valve disc, but may also use poppets, reeds, etc., and are limited to using a spring with a reaction force against the piston as a spring to seat the valve disc. Alternatively, the restoring force of the reed valve body or the like may be used.

[Effect of idea]

As explained above, according to the present invention, it is possible to suppress the surge pressure and prevent the chattering phenomenon, thereby preventing the noise caused by the chattering phenomenon in the direct acting relief valve and the pulsation of the hydraulic circuit. At the same time, the performance of the direct acting relief valve itself and the hydraulic circuit to which it is connected can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a direct acting relief valve which is an embodiment of the present invention, and FIGS. 2 and 3 are diagrams for explaining the effects thereof. FIGS. 4 and 5 are vertical sectional views showing conventional examples, respectively. 11...Body, 12...Hollow part, 13...Inlet passage, 14...Outlet passage, 15...O ring,
16... Valve cylinder, 17... Valve chamber, 18... Valve seat, 1
9...Inlet port, 20...Outlet port, 21...
... Poppet (valve body), 22 ... Pressure adjustment spring, 23 ... Adjustment screw member, 24 ... Lock nut, 25 ... Damping chamber, 26 ... Piston, 27 ... Valve stem, 28 ... Check valve , 29...
Valve port, 30...valve seat, 31...ball (valve body),
32...Spring.

Claims (1)

[Scope of utility model registration request] In a direct acting relief valve equipped with a damping chamber configured to vary its volume following the opening/closing operation of the valve body, the damping chamber is provided with a check valve, and this reverse A direct acting relief valve, characterized in that the stop valve is configured to open a damping chamber when the valve body moves in the opening direction, and close the damping chamber when the valve body moves in the closing direction. .