KR0149159B1 - Relief valve of a brake circuit - Google Patents

Abstract

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Description

Relief Valve for Brake Circuit

1 is a cross-sectional view of a relief valve for a brake circuit according to an embodiment of the present invention.

2 is a partial cross-sectional view showing the relationship between the valve seat cylinder and the main valve.

3 is a cross-sectional view of a relief valve for a conventional brake circuit.

4 is a characteristic curve diagram of a relief valve for a brake circuit.

* Explanation of symbols for main parts of the drawings

1: Relief valve for brake circuit 2: Internal structure

3: valve body 5: motor

6: balance valve 7: switching valve

8: pump 10: pressure regulating spring

11: valve seat cylinder 12,25: slit

13,22: aperture hole 14,15: piston

17: passage 18: cross passage

19: main valve 20: pressure chamber

23: check valve 24: spring

26: pressure chamber 27: rod

28: cylinder

[Industrial use]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a relief valve for a brake circuit which is used for driving an inertial body (load) such as a hydraulic insertion or a crane, and controls an increase in the fluid pressure during inertial body driving to prevent the occurrence of an impact.

[Prior art]

Conventional relief valves for brake circuits are disclosed in FIG. 3 (Japanese Patent Laid-Open No. 52-23034) of the present application.

In the brake circuit relief valve 1, since the brake circuit relief valve 1 is formed symmetrically about the valve seat cylinder 50, only the configuration on the right side will be described. A dash is attached to the same number and a detailed description thereof is omitted.

The brake circuit relief valve 1 is provided with a valve seat cylinder 50 so as to be movable in an inner hole 2 provided in the center of the valve body 3, and a cross passage (a) in the valve seat cylinder 50. 18 is provided, and a main valve 51 having an aperture hole 22 is provided so as to abut against the open hole end of the cross passage 18. The main valve 51 is fitted with a pressure regulating spring 10 to which pressure is applied by the piston 52. The piston 52 forms a pressure chamber 20 between the valve body 3, and the pressure chamber 20 has a passage through which a sliding motion is freely inserted into the main valve 51 and the piston 52. It is connected to the rod 27. The hydraulic pressure acting on the main valve 51 is transmitted through the passage of the rod 27.

In addition, the cross-sectional area of the pressure chamber 26 formed at the interposed portion of the rod 27 and the main valve 51 is smaller than the cross-sectional area of the cross passage 18. Therefore, the main valve 51 is configured such that the pressure applied by the hydraulic pressure acting as a difference in the pressure receiving area between the cross passage 18 and the pressure chamber 26 exceeds the pressure applied by the pressure regulating spring 10. .

Next, the operation will be described.

In FIG. 3, the switching valve 7 is operated to the switching position 7A so that the hydraulic pressure from the pump 8 flows in through the passages a ₁ and a ₂ through the balance valve 6, and the motor 5 To rotate in the direction of the arrow. At this time, the pressure in the passages a ₁ and a ₂ rises to a value corresponding to the degree of the weight W.

At this time, the valve seat cylinder 50 is moved to the left by hydraulic pressure acting on the passages a ₁ and a ₂ so that the open-hole portion at the left end of the cross passage 18 abuts against the main valve 51 '. Since the hydraulic pressure acts on the entire main cross-sectional area of the other main valve 51, it moves in the right direction and the passage between the right end of the cross passage 18 and the main valve 51 is greatly opened. The hydraulic pressure acting from the passage through the cross passage 18 acts on the pressure chamber 20 'via the aperture hole 22' of the main valve 51 'and the passage of the piston 27'.

For this reason, the piston 52 'compresses the pressure regulating spring 10' between the open hole area of the aperture hole 22 'and the time t ₂ determined according to the capacity of the pressure chamber 20'. Thus, between the channel (a _1, a ₂₎ of the pressure is the operating time (t) and as shown in the fourth-degree curve (C ₁₎ showing the relationship between the pressure (p), the time (t ₂₎ It rises from the pressure P ₁ to the pressure pressure P ₂ . This characteristic curve C ₁ is set to such an extent that an impact does not occur in a circuit.

Therefore, in the conventional brake circuit relief valve ₁ , when the pressure in the passages a ₁ and a ₂ tries to rise beyond the characteristic curve C ₁ , the main valve 51 ′ becomes the valve seat cylinder 50. Limit the pressure rise in the passages a ₁ and a ₂ that deviate from. For this reason, even when a large amount of fluid is supplied to the passages a ₁ and a ₂ due to the sudden operation of the switching valve 7, the hydraulic pressure of the passages a ₁ and a ₂ increases according to the characteristic curve C ₁ . This prevents the shock caused by the sudden pressure rise in the passage (a ₁ , a ₂ ).

[PROBLEMS TO BE SOLVED BY THE INVENTION]

Since the pressure regulating spring of the relief valve for brake circuit needs to change the set pressure from low pressure P ₁ to high pressure P ₂ as shown in the characteristic curve C _{1 of} FIG. 4, the spring constant It is necessary to increase the displacement of the pressure regulating spring by decreasing the value of. Thus, the length of the pressure regulating spring is longer than the length of the pressure regulating spring of a general relief valve which does not have a function of anti-shock. Therefore, the conventional relief valve for brake circuits in which such pressure regulating springs are provided on two same axes has a drawback in that it extends in the axial direction.

The present invention is intended to solve the above problems by using one pressure regulating spring.

[Means for solving the problem]

Means of the present invention for solving the above problems, by installing an inner hole in the center of the valve body to insert the valve seat cylinder freely sliding in the inner hole, and to install the main valve so as to be opposed to both ends of the valve seat cylinder, A relief valve for brake circuits in which a pressure regulating spring and a piston are provided in the axial direction of the main valve, and the piston is moved to the main valve side by the hydraulic pressure on the main valve side associated with the piston so that the pressure regulating spring increases the spring force. In which the valve seat cylinder is divided into two, one pressure regulating spring is provided between the two valve seat cylinders, and the main valve installed to abut against each of the two valve seat cylinders is pressurized by the piston. A check block for preventing the flow from the passage to the inner hole between the inner hole and the passage (止) it is characterized in that a valve in the outer edge of the main valve.

[Action]

The relief valve for brake circuit which concerns on this invention divides a valve seat cylinder into two, and presses by the hydraulically actuated piston acting on the main valve by the main valve provided so that it may face each of these two valve seat cylinders. In this configuration, a check valve is provided on the outer edge of the main valve between the inner hole and the passage to prevent the flow from the passage to the inner hole, so that the pressure regulating spring 1 can be used. It is possible to shorten the dimension in the longitudinal direction of the dog share.

EXAMPLE

FIG. 1 shows an embodiment of the present invention.

In addition, as shown in FIG. 1, since the relief valve 1 for brake circuits is comprised symmetrically about the pressure regulating spring 10, only the structure of the right side is demonstrated, The configuration is indicated by attaching dashes to the same numbers, and detailed description is omitted.

The brake valve relief valve (1) is a valve seat in which a sliding motion is fitted freely against the pressure regulating spring (10) and the pressure regulating spring (10) in the inner hole (2) of the valve body (3). The cylinders 11 and 11 'are provided. The valve seat cylinder 11 has a diaphragm hole 13 at its center, and constitutes a valve seat 13a on which the main valve 19 abuts on the right side thereof, and on the right side, a piston 14 is provided. The cylinder body 28 which slides freely is provided. Moreover, the slit 12 is provided in the valve seat cylinder 11, and the pressure fluid which flowed in into the inner hole 2 can pass freely.

The main valve 19 is in the shape of a cylinder integrally formed in the piston 15 in which the sliding motion is freely fitted in the inner hole 2a formed in the same diameter as the inner hole 2, and the front end thereof is the valve seat ( It has a crossover passage 18 therein against 13a). It communicates with the passages a ₁ and a ₂ via the cross passage 17 of the main valve 19 and communicates with the pressure chamber 20 via the aperture hole 22.

As shown in FIG. 2, the diameter d ₂ of the portion where the front end of the main valve 19 abuts the valve seat 13a is larger than the diameter d ₁ of the inner diameter of the pressure chamber 26. As shown in FIG. The pressing force of the valve seat cylinder 11 is caused by the difference between the hydraulic force acting as a difference between the butting place and the pressure receiving area of the pressure chamber and the spring force of the pressure regulating spring 10. Therefore, when the difference between the diameter d ₂ and the diameter d ₁ is reduced, the pressing force is reduced.

In addition, the check valve 23 is freely slid at the outer edge of the main valve 19, and the check valve 23 has a pressure from the passages a ₁ and a ₂ toward the inner hole 2. The flow of fluid is blocked. The check valve 23 is provided with a slit 25 at a portion where the sliding motion is freely fitted into the inner hole 2, and the inner hole 2 is provided at a spring 24 having one end against the piston 15. It is pressurized by the valve seat 2c formed at the end of the valve.

The operation of the embodiment having the above configuration will be described.

In FIG. 1, when the switching valve 7 is operated to the switching position 7A, the hydraulic pressure in the pump 8 passes through the balance valve 6 to the motor 5 via the passages a ₁ and a ₂ . Inflow. At this time, the hydraulic pressure in the passages a ₁ and a ₂ reaches the cross passage 18 from the passage 17, and acts on the pressure chamber 20 via the aperture hole 22 and at the same time the pressure chamber 26. Works. The hydraulic pressure acting on the pressure chamber 26 pressurizes the piston 14 until it opposes the piston 14 'on the opposite side in the left direction. At the same time, the piston 15 starts to operate in the left direction due to the fluid pressure flowing into the pressure chamber 20.

As described above, when the piston 14 is against the piston 14 ', the pressing force by the hydraulic pressure of the valve seat cylinder 11 acting on the pressure regulating spring 10 is reduced by the pressure chamber 26 and the valve seat 13a. ) And the abutment between the main valve 19 become a small value of the difference between the reception area of the part, so that the set pressure is a value shown in the pressure P ₁ of FIG. So again, over time, the piston 15 moves to the left. As a result, since the pressure regulating spring 10 is compressed via the valve seat cylinder 11 by the movement of the piston 15, the set pressure gradually rises as shown in the characteristic curve C ₁ of FIG. . This characteristic curve C ₁ is set to such an extent that an impact does not occur.

Therefore, when the rising ratio with respect to the hydraulic time of the passages a ₁ and a ₂ exceeds the characteristic curve C ₁ , the passages a ₁ and a ₂ are separated from the main valve 19 of the seat cylinder 11 of the valve. The pressure fluid of is discharged from the inner hole 2 via the check valve 23 'to the passages b ₁ and b ₂ , so that the increase in the hydraulic pressure is limited.

Therefore, it is possible to prevent the shock caused by the rapid rise of the hydraulic pressure.

As described above, when the switching valve 7 is operated to the switching position 7B, the hydraulic pressure in the passages b ₁ and b ₂ is transferred to the main valve 19 ', the valve seat cylinder 11' and the pressure regulating spring 10. As a result, it is controlled to a value according to the characteristic curve C _{1 of} FIG. 4 as with the operation of the passages a ₁ and a ₂ , thereby preventing an impact by hydraulic pressure.

[Effects of the Invention]

According to the present invention, the valve seat cylinder is divided into two, and the pressure valve is pressurized by the piston to install a pressure regulating spring between two valve seat cylinders so as to face each of the two valve seat cylinders. As a result, the axial dimension of the relief valve for the brake circuit is reduced by one share of the pressure regulating spring.

In addition, since a check valve is provided at the outer edge of the main valve between the inner hole and the passage to which the passage is connected, the dimension of the radial direction increases by the share of the check valve.

Therefore, the shape of the relief valve for a brake circuit can be made close to square, and this has the effect of being easy to assemble with circular devices, such as a hydraulic motor.

In addition, since the valve seat cylinder is divided into two parts and a pressure regulating spring is provided therebetween, the installation position of the pressure regulating spring can be made into the entire inner hole. The restriction is relaxed, so that the design of the pressure regulating spring is facilitated.

Claims (1)

An inner hole is provided at the center of the valve body, a sliding seat is inserted into the inner hole freely, and a main valve is installed so as to be opposed to both ends of the valve seat cylinder, and a pressure regulating spring in the axial direction of the main valve is provided. And a piston, wherein the piston is moved to the main valve side by the hydraulic pressure on the main valve side thereof to increase the spring force of the pressure regulating spring, wherein the valve seat cylinder is divided into two parts. One pressure regulating spring is provided between the two valve seat cylinders, and a main valve installed so as to be opposed to each of the two valve seat cylinders is pressed by the piston, and the inner hole is connected to the passage. To the outer edge of the main valve Relief valve for the brake circuit, characterized in that the groping.

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