JP2538159Y2 - Two-way relief valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention restricts the flow of high-pressure fluid discharged from a fluid motor when the fluid motor performs a pump action, and applies a brake to the fluid motor. The present invention relates to a two-way operation relief valve used for a fluid brake device or the like.

[Prior Art] As shown in FIG. 5, a check valve 5 and a fluid are connected to first and second main circuits 3, 4 for connecting first and second ports 1a, 1b of a fluid motor 1 and an operation valve 2. A brake valve (6) is provided for regulating the flow of fluid from the motor (1) to the operation valve (2). The flow of high-pressure fluid discharged from the fluid motor (1) is restricted by the brake valve (6) when the fluid motor (1) performs a pumping operation. A fluid brake device for applying a brake to a motor 1 is known.

In such a fluid brake device, since the pressure between the fluid motor 1 and the brake valve 6 in the first and second main circuits 3 and 4 becomes high, the first main circuit is provided by providing a pair of relief valves 7 and 7. 3 is relieved to the second main circuit 4, and the high-pressure fluid of the second main circuit 4 is relieved to the first main circuit 3.

[Problems to be solved by the invention]

Such a fluid brake device is provided with a pair of relief valves, so that the number of parts is large and the cost is high. In addition, since two safety valve mounting holes are formed, the processing becomes troublesome. Since the mounting is performed over the main circuit and the second main circuit, the field area is increased.

Therefore, as shown in Japanese Utility Model Application Laid-Open No.
There has been proposed a fluid brake device provided with a single relief valve that operates in both directions over the second main circuit. This relief valve has a pressure receiving area on the first main circuit side and a pressure receiving area on the second main circuit side. However, since the flow path shape is different, the relief start pressure and the relief pressure are different.

Therefore, an object of the present invention is to provide a two-way operation relief valve capable of solving the above-mentioned problem.

[Means and actions for solving the problem]

A cylindrical body 15 having a through hole 19 that communicates the first port 12 and the second port 13, one of which is at a high pressure while the other is at a low pressure, and a blind hole 25 a and a blind hole 25 b on the other side of the partition wall 25 e. A free piston 25 having a projection 25d protruding toward the other blind hole 25b at the center of the partition wall 25e and having a small hole 29 communicating the one blind hole 25a and the other blind hole 25b to the projection 25d.
And the tapered surface 25c on the other side blind hole 25b side of the free piston 25
Is pressed against one end surface of the cylindrical body 15 to make the first port 12 and the second port
A spring 30 that shuts off the port 13; and a piston 27 that is inserted into one side blind hole 25a of the free piston 25 and forms a pressure receiving chamber 28 between the partition 25e and the taper surface 25c of the free piston 25. Tubular body 1
The second port 1 is located on the outer peripheral portion from the pressure contact portion with one end surface of
The pressure on the first port 12 acts on the inner peripheral part of the pressure contact portion, and the pressure on the first port 12 acts on the free piston 25.
Is pressed in the direction of communication between the first port 12 and the second port 13 and the free piston is acted upon by the pressure on the second port 13 side.
A two-way operation relief valve characterized in that the pressure receiving area for pressing 25 in the direction in which the first port 12 and the second port 13 are communicated is the same.

Thus, the pressure at which relief is started by the high-pressure fluid on the first port 12 side and the pressure at which relief is started by the high-pressure fluid on the second port 13 side can be made the same. When the relief is performed from the second port 13 side to the first port 12 side, the high-pressure fluid flowing toward the partition 25e along the tapered surface 25c of the free piston 25 is projected.
25d, the pressure at the tip of the projection 25d becomes a negative pressure, and the pressure in the pressure receiving chamber 28 becomes a negative pressure, so that the force for closing the free piston 25 is significantly reduced, so that the override performance is extremely good. Become.

〔Example〕

As shown in FIG. 1, a first port 12 and a second port 13 and a hole 14 communicating the first port 12 and the second port 13 are formed in a hydraulic device body 11 such as a motor body of a fluid motor. A cylindrical body 15 and a sleeve 16 constituting the two-way operation relief valve 10 are fitted in the holes 14, and the cylindrical body 15 has a large diameter portion 17 and a small diameter portion 18 as shown in FIG. And through holes
A large-diameter portion 17 fits tightly into the hole 14 via the sealing material 20, a through-hole 19 opens in the first port 12, and a base intermediate-diameter hole 21 at the end of the sleeve 16, and a large-diameter intermediate portion. Diameter hole 22, tip small diameter hole 23
A hole 24 is formed in the middle portion large-diameter hole 22, and a hole 14 is formed so that the tip small-diameter hole 23 fits tightly into the small-diameter portion 18 of the cylindrical body 15.
Screwed into the sleeve, and the base intermediate diameter hole of the sleeve 16
A free piston 25 is slidably fitted to 21.

A piston 27 provided in a spring receiver 26 is slidably fitted in one side blind hole 25a of the free piston 25 to form a pressure receiving chamber 28. Opened in the blind hole 25b, the other side blind hole 25b communicates with the through hole 19 of the tubular body 15, and the free piston 25 is pushed by the spring 30 toward the tubular body 15 side to form a tapered surface 25c. The spring chamber 31 is connected to a tank 33 through a drain passage 32 by being pressed against the distal end surface 18a of the small diameter portion 18 of the cylindrical body 15.

The fine hole 29 of the free piston 25 is bored in a projection 25d provided integrally with the center of the partition 25e of the free piston 25.

Because of this, the first port 12 and the second port 13 are sealed by a crimping portion between the distal end surface 18a of the small diameter portion 18 of the cylindrical body 15 and the tapered surface 25c of the free piston 25, and the free piston 25 is High pressure fluid in port 12 and second port 13
Moves against the spring 30 by the high pressure fluid of the first port 12
To the second port 13 and the free piston
Pressure receiving area where high-pressure fluid acts on the first port 12 at 25
S ₁ is determined by the equation (1) based on the diameter d _{1 of the} crimping portion and the diameter d _{2 of the} piston 27, and the pressure receiving area S ₂ of the free piston 25 where the high-pressure fluid acts on the second port 13 is equal to the diameter of the crimping portion. Diameter
Since determined in (2) by a diameter d ₃ of d ₁ and the free piston 25, the diameter d _1, d _2, By setting d _{3 so} that S ₁ = S ₂ , the free piston 25
Since the pressure receiving areas on which the high pressure fluids of the first and second ports 12 and 13 act are equal, the relief start pressure for relief by the high pressure fluid of the first port 12 and the relief start pressure for relief by the high pressure fluid of the second port 13 Are the same.

Further, since the pores 29 are formed in the projection 25d integrally provided at the center of the partition 25e of the free piston 25, the override performance when the high-pressure fluid is relieved from the second port 13 to the first port 12 is extremely low. Get better.

That is, when the high-pressure fluid flows from the second port 13 to the first port 12, the high-pressure fluid flows toward the center of the partition wall 25e along the tapered surface 25c of the free piston 25, and the high-pressure fluid stagnates near the center. Since the pressure becomes higher than the pressure on the outer periphery, and the flow velocity of the high-pressure fluid becomes faster as the distance from the center toward the outer periphery increases, the pressure from the second port 13 to the first port 12 increases.
When the high-pressure fluid is relieved, the partition 25 of the free piston 25
2 and 3, the pressure distribution A in the center is a high-pressure portion A 'near the center and a low-pressure portion A "in the outer periphery, and the fine holes 29 are located in the center of the partition 25e of the free piston 25 as shown in FIG. , The high-pressure oil in the high-pressure portion A 'enters the pressure receiving chamber 28 through the fine holes 29, so that the force in the direction in which the free piston 25 is closed becomes large and the override performance deteriorates. However, as shown in FIG.
Is pierced into the projection 25d projecting from the high-pressure portion A 'of the partition 25e, the high-pressure fluid flowing toward the center of the partition 25e flows along the projection 25e as shown by the arrow a in FIG.
The distal end of the projection 25d has a negative pressure, and the pressure in the pressure receiving chamber 28 has a negative pressure. Therefore, the force in the direction in which the free piston 25 is closed becomes smaller, and the override performance is extremely improved.

Further, the fluid passage is the same whether the relief is performed from the first port 12 to the second port 13 or the relief is performed from the second port 13 to the first port 12. And the crimping portion of the distal end portion 18a of the cylindrical body 15, and the free piston 25 and the spring 30 are common.

Further, since the sleeve 16 can be removed in a state where the two-way operation relief valve 10 is assembled by extracting the sleeve 16 from the valve main body 11, the removal and mounting work becomes easy.

Also, loosen the lock nut 34 and tighten the spring receiver 26,
By loosening, the mounting load of the spring 30 can be changed to adjust the relief start pressure.

In addition, as shown in FIG.
Since 18a is in contact with the tapered surface 25c of the free piston 25, the high-pressure fluid flowing from the second port 13 directly acts on the tapered surface 25c without being throttled. And the override performance is further improved.

[Effect of the invention]

The pressure at which relief is started with the high-pressure fluid on the first port 12 side and the pressure at which relief is started with the high-pressure fluid on the second port 13 side can be made the same. When the relief is performed from the second port 13 side to the first port 12 side, the high-pressure fluid flowing toward the partition 25e along the tapered surface 25c of the free piston 25 flows along the projection 25d, and the tip of the projection 25d The pressure becomes a negative pressure, and the pressure in the pressure receiving chamber 28 becomes a negative pressure, so that the force for closing the free piston 25 is significantly reduced, so that the override performance is extremely improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2, FIG. 3 is an explanatory view of an operation in which pressure oil is introduced into a pressure receiving chamber, FIG. 4 is an enlarged view of a seat portion, FIG. Is a sectional view of a conventional example. 12 is a first port, 13 is a second port, 25 is a free piston, 25d is a projection, 25e is a through hole, 25f is a piston, 28 is a pressure receiving chamber, 29 is a pore, and 30 is a spring.

Claims (1)

(57) [Scope of request for utility model registration] 1. A cylindrical body 15 having a through-hole 19 communicating between a first port 12 and a second port 13, one of which is at a high pressure while the other is at a low pressure. It has a side blind hole 25b,
At the center of the partition wall 25e, a projection 25d protruding toward the other blind hole 25b is provided.The projection 25d has one blind hole 25a and the other blind hole 2.
A free piston 25 having a narrow hole 29 communicating with the free piston 5b; and a tapered surface 25c on the other side blind hole 25b side of the free piston 25 pressed against one end surface of the cylindrical body 15 to form a first port 12 and a second port. A spring 30 for shutting off 13; a partition wall 2 inserted into one side blind hole 25a of the free piston 25;
5e and a piston 27 forming a pressure receiving chamber 28, and the cylindrical body 15 on the tapered surface 25c of the free piston 25.
The second port 13 is provided on the outer peripheral portion of the outer peripheral portion of the pressure contact portion with one end surface of the
Pressure acts on the first port 12 side on the inner peripheral portion of the pressure contact portion. The pressure on the first port 12 acts to move the free piston 25 to the first port 12. The pressure receiving area that pushes the second port 13 in the communicating direction and the pressure on the second port 13 side act to operate the free piston 25.
Characterized in that the pressure receiving area for pressing the pressure in the direction in which the first port 12 and the second port 13 communicate with each other is the same.