JPH04312201A - Pressure control valve - Google Patents

Abstract

PURPOSE:To prevent vibrations, failures, damages or the like of passages and hydraulic equipment by employing a cross-over relief valve in a hydraulic circuit for driving a body of inertia. CONSTITUTION:A sub-valve body 18 which is provided to a guide member 15 in a slidable manner is mounted on/released from a main valve body 16 where the first reducing oil passage 24 communicated with a main pipe passage 4A is recessed. There are provided the first pressure chamber 20 between the sub-valve body 18 and the main valve body 16 and the second pressure chamber 22 between the sub-valve body 18 and the guide member 15 respectively, and these two pressure chambers are communicated through the second reducing oil passage 25. When the sub-valve body 18 is released from a valve seat 16A of the main valve body 16, the pressure in the first pressure chamber 20 is introduced into a spring chamber 12 through the third reducing oil passage 26, and the spring chamber 12 and a main pipe passage 4B are communicated with each other through the fourth reducing oil passage 28 recessed in a valve 11.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a pressure control valve that is suitably used as a crossover relief valve in a hydraulic circuit for driving an inertial body such as construction machinery, and in particular, the present invention relates to a pressure control valve that is suitably used as a crossover relief valve in a hydraulic circuit for driving an inertial body of construction machinery, etc. This invention relates to a pressure control valve that can alleviate the effects of

0002

[Prior Art] Generally, in a hydraulic circuit for driving an inertial body, such as a running system or a swing system of a hydraulic excavator, a hydraulic actuator such as a hydraulic motor is connected to a hydraulic pump and a tank through a pair of main pipes. In the middle, a directional switching valve is provided near the hydraulic pump and tank side, and a brake valve is provided near the hydraulic actuator side, and the brake valve is equipped with a counter balance valve and a pair of crossover relief valves as pressure control valves. I am trying to set it up.

0003

By the way, in the above-mentioned prior art hydraulic circuit for driving an inertial body, when the directional control valve is switched from the neutral position to start the hydraulic actuator,
Alternatively, when the directional control valve is returned to the neutral position and the hydraulic actuator is braked by a brake valve or the like in order to stop the inertial body that is being driven, the hydraulic circuit is The oil pressure may rise to a peak pressure in some areas, and this peak pressure causes problems such as vibration, failure, and damage to pipes, hydraulic equipment, and the like.

For this reason, for example, Japanese Patent Publication No. 60-14236
In the above publications, the brake valve is provided with a pressure increase relief valve separately from the crossover relief valve to solve the above problem, but in this case, the brake valve is provided with a pressure increase relief valve in addition to the crossover relief valve. Since it is necessary to provide a valve, there is a problem that the structure of the entire brake valve becomes complicated and large.

The present invention was developed in view of the problems of the prior art described above, and the present invention prevents vibration, failure, damage, etc. of pipes and hydraulic equipment when used as a crossover relief valve in an inertial drive hydraulic circuit. It is an object of the present invention to provide a pressure control valve that can be miniaturized and formed compactly, as well as prevent such problems.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention consists of a cylindrical body, with one side serving as the main valve seat across the main valve body sliding hole formed in the axially intermediate portion. a valve body whose other side is a spring chamber; a main valve body which is slidably inserted into a main valve body sliding hole of the valve body; a pressure setting spring that urges the valve body to seat on the main valve seat; a cylindrical guide member provided on the spring chamber side of the valve body; provided on the spring chamber side of the main valve body, one side defining a first pressure chamber within the main valve body, and the other side being slidably inserted into the guide member and having a larger pressure receiving area than the first pressure chamber. a first throttle formed in the main valve body so as to guide the primary side pressure acting on the main valve body to the first pressure chamber; an oil passage, a second throttle oil passage bored in the sub-valve body so as to guide the pressure in the first pressure chamber to a second pressure chamber, and the sub-valve body separated from the main valve body. When the valve body is seated, a third throttle oil passage that guides the pressure in the first pressure chamber to the spring chamber of the valve body communicates with a secondary side, and a hole is formed in the valve body. A configuration consisting of a fourth throttle oil passage provided is adopted.

[0007] Furthermore, it is preferable that a piston is slidably provided within the guide member in order to enlarge the second pressure chamber defined by the sub-valve body.

[0008]

[Function] With the above configuration, when the pressure control valve is used as a crossover relief valve in an inertial body drive hydraulic circuit, when the primary side pressure suddenly increases, this pressure is first transferred to the first throttle oil passage of the main valve body. The auxiliary valve body is separated from the main valve body by acting on the first pressure chamber through the pressure chamber, and the pressure in the first pressure chamber acts on the second pressure chamber through the second throttle oil passage. , acts on the spring chamber via the third throttle oil passage, and in this state, the main valve element opens, thereby providing low pressure relief for the primary side pressure. Then, as the pressure in the second pressure chamber increases, the sub-valve element seats on the main valve element, and this low-pressure relief state is maintained for a short period of time until the third throttle oil passage is cut off from the spring chamber. can be maintained, and then the main valve body can be relieved of high pressure. In addition, pressure can be generated in the spring chamber by throttling the pressure oil flowing out from the spring chamber to the secondary side in the fourth restricting oil passage, and this sets the pressure when the main valve body performs low pressure relief. can.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to FIGS. 1 to 3, taking as an example a case in which a pressure control valve is used as a crossover relief valve in a hydraulic circuit for driving an inertial body.

In the figure, reference numeral 1 denotes a hydraulic motor as a hydraulic actuator for rotationally driving an inertial body, and the hydraulic motor 1 has its respective supply and discharge ports connected to a hydraulic pump 2 and a tank 3 through a pair of main pipes 4A and 4B. The hydraulic motor 1 is rotatably driven by pressure oil from a hydraulic pump 2. Reference numeral 5 indicates a directional switching valve located near the hydraulic pump 2 and tank 3 side, and provided in the middle of the main pipes 4A and 4B. to switching position (B) or (
c), and the hydraulic motor 1 is rotated in one direction or the other direction.

Reference numeral 6 indicates a brake valve located near the hydraulic motor 1 side and provided in the middle of the main pipes 4A, 4B. A counterbalance valve 7 that is switched from a neutral position (a) to a switching position (b) or (c) almost in conjunction with the directional switching valve 5, and branch pipes 8A and 8B that communicate between the main pipes 4A and 4B, respectively. It consists of crossover relief valves 9 and 10 as pressure control valves provided midway, and the crossover relief valves 9 and 10 are constructed as described below. When the brake valve 6 returns the directional control valve 5 to the neutral position (A) and the counterbalance valve 7 returns to the neutral position (A), either of the crossover relief valves 9 and 10 opens. Then, hydraulic motor 1
The pressure in the main pipe 4A or 4B due to inertial rotation is relieved to the low pressure side, and braking force is applied to the hydraulic motor 1.

Next, the crossover relief valve 9 as a pressure control valve will be described in detail with reference to FIG. 2. Note that the crossover relief valve 10 is the crossover relief valve 9.
Since the configuration is almost the same as that, the explanation thereof will be omitted.

In the figure, reference numeral 11 indicates a cartridge-type valve body constituting the valve casing of the crossover relief valve 9. The valve body 11 is a stepped cylindrical body, and a valve body 11 is formed in the axially intermediate portion thereof. One side of the main valve body sliding hole 11A is protruded toward the main conduit 4A side, and the other side is a guide member 15 which will be described later.
A large diameter spring chamber 12 is formed between the two. A cylindrical valve seat member 13 is provided on one side of the valve body 11, in which a main valve seat 13A is formed and an oil hole 13B communicating with the branch pipe 8A is provided inside the valve seat member 13. Oil holes 11B, 11B, . . . are bored in the radial direction to communicate the primary side main pipe 4A with the secondary side main pipe 4B via the member 13.

Reference numeral 14 is located on the other side of the valve body 11, is screwed onto the valve body 11 from the outside, and is connected to a pressure setting spring 1, which will be described later.
7 is a plug for adjusting the set load; 15 is a bottomed cylindrical guide member that is fitted on the other side of the valve body 11 and is prevented from coming out by the plug 14; It consists of a small-diameter cylindrical portion 15A extending in the axial direction, and a large-diameter annular portion 15B located on the base end side of the small-diameter cylindrical portion 15A and closing the other side of the valve body 11. The annular portion 15B will be described later. It also serves as a spring seat for the pressure setting spring 17. The small-diameter cylindrical portion 15A of the guide member 15 is configured to slidably guide a sub-valve body 18 and a piston 21, which will be described later, in the axial direction.

Reference numeral 16 indicates a main valve body slidably inserted into the main valve body sliding hole 11A of the valve body 11, and the main valve body 16 is connected to a pressure setting spring disposed in the spring chamber 12. 17, the valve seat member 13 is always urged toward the main valve seat 13A side, and is seated on and off the valve seat member 13 with a pressure receiving area S1. When the main valve body 16 opens against the pressure setting spring 17 due to the pressure on the branch pipe 8A side, the pressure oil in the main pipe 4A (primary side) is transferred to the main pipe 4B (secondary side). The oil is made to flow through each oil hole 11B. Here, the main valve body 16 is formed as a poppet valve body in the shape of a covered cylinder, and a valve seat 16A on which the sub-valve body 18 is seated is formed on the opening side end surface thereof.

Reference numeral 18 indicates a sub-valve body provided on the spring chamber 12 side of the valve body 11 so as to sit on and off the valve seat 16A of the main valve body 16. Member 15
a valve portion 18A formed in a substantially conical shape and located between the small diameter cylindrical portion 15A;
A cylindrical head 18B inserted into the main valve body 16, and a cylindrical sliding portion extending in the axial direction from the base end side of the valve portion 18A and slidably inserted into the small diameter cylindrical portion 15A. 18C, an oil passage 18D that communicates with the second pressure chamber 20 via a second throttle oil passage 25 (described later), and a valve part 18A that controls the lift amount by coming into contact with the tip of the small diameter cylinder part 15A. and an annular flange 18E formed adjacent to the flange 18E. A weak spring 19 is disposed between the flange 18E and the outer periphery of the small-diameter cylindrical portion 15A of the guide member 15 in the sub-valve body 18. It is constantly energized toward the seat 16A.

20, the head 18B of the sub-valve body 18 is the main valve body 1.
6, the pressure inside the pressure chamber 20 is the first pressure chamber defined within the main valve body 16.
6 and the sub-valve body 18 have a pressure receiving area S2 (S2 <S1
).

Reference numeral 21 indicates a piston that is slidably inserted into the small diameter cylindrical portion 15A of the guide member 15.
1 defines a second pressure chamber 22 in the small diameter cylindrical portion 15A with the sub-valve body 18, and the pressure within the pressure chamber 22 is applied to the sub-valve body 18 and the piston 21 in a pressure receiving area S3 (S2 < S3 <
S1). Reference numeral 23 indicates an oil liquid storage chamber located at the inner part of the small diameter cylindrical portion 15A and defined between the guide member 15 and the piston 21.

Reference numeral 24 denotes a first throttle oil passage bored in the main valve body 16 so as to guide the primary side pressure P1 acting on the main valve body 16 from the valve seat member 13 side into the first pressure chamber 20; 25 is the first
The figure shows a second throttle oil passage bored in the head 18B of the sub-valve body 18 so as to guide the pressure inside the pressure chamber 20 into the second pressure chamber 22. 26 indicates a third throttle oil passage diagonally bored in the head 18B of the sub-valve body 18, and this throttle oil passage 25 is opened when the sub-valve body 18 is separated from the valve seat 16A of the main valve body 16. The pressure within the first pressure chamber 20 is guided into the spring chamber 12 during the first period, and is normally shut off from the spring chamber 12. These throttle oil passages 24, 25, and 26 are connected to the first pressure chamber 20 while the primary pressure P1 is introduced into the first pressure chamber 20 and the sub-valve body 18 is separated from the valve seat 16A. In order to maintain the pressure inside 20 at a constant pressure lower than the primary side pressure P1, each channel is formed with a predetermined area.

Reference numeral 27 denotes an oil passage bored on the base end side of the guide member 15 in order to communicate the oil liquid storage chamber 23 with the inside of the spring chamber 12;
Furthermore, 28 is a main conduit 4B which is a secondary side inside the spring chamber 12.
A fourth throttle oil passage 28 is shown bored in the valve body 11 to communicate with the first pressure chamber 20 when the sub-valve body 18 is separated from the valve seat 16A. Spring chamber 12 from inside
The oil flowing into the spring chamber 12 from the oil storage chamber 23 through the oil passage 27 when the piston 21 slides is constricted to the main pipe 4B side by a predetermined throttle. It is designed to be discharged with action.

The hydraulic circuit for driving an inertial body according to this embodiment has the above-described configuration, and next, the directional control valve 5 is switched from the neutral position (a) to the switching position (b), and the hydraulic motor 1 is started. The operation will be explained using an example where the

First, the pressure oil from the hydraulic pump 2 is transferred to the main pipe 4A via the directional control valve 5 which has been switched to the switching position (B).
The pilot pressure from the pilot line 7A switches the counterbalance valve 7 to the switching position (B), and generates the primary side pressure P1 in the main line 4A and the branch line 8A, thereby turning the hydraulic motor 1 on. It will start up. In this case, since the hydraulic motor 1 starts up the inertial body which is in a stopped state, the primary side pressure P1 becomes a peak pressure and tries to rise rapidly.

In this case, the primary side pressure P1 is the main valve body 16
The pressure P2 (P2
<P1) occurs, and the sub-valve body 18 is opened against the weak spring 19 at time T1 illustrated in FIG. 3 before the peak pressure is generated. Here, if the spring load of the pressure setting spring 17 is F1, the spring load of the weak spring 19 is F2, and the pressure inside the second pressure chamber 22 is P3, in this case, the pressure P3
is initially at tank pressure, so

[0024]

[Equation 1]P2×S2>P3×S3+F2, and the sub-valve body 18 is separated from the valve seat 16A of the main valve body 16.

When the sub-valve body 18 is separated from the valve seat 16A, the first pressure chamber 20 communicates with the spring chamber 12 via the third throttle oil passage 25, so that the pressure inside the pressure chamber 20 is The pressure P2 is determined by the flow rate of the pressure oil flowing through the first, second, and third restricted oil passages 24, 25, and 26.

In this case, the pressure oil flowing into the pressure chamber 20 through the first throttle oil passage 24 flows into the second pressure chamber 22 through the second throttle oil passage 25, Since the pressure P3 is generated in the spring chamber 12 through the third throttle oil passage 26, the pressure P3 is generated in the first pressure chamber 12, compared to the case where the third throttle oil passage 26 is not provided. The pressure P2 inside 20 can be maintained at a lower pressure. Moreover, as a result, the pressure within the second pressure chamber 22 that acts on the piston 21 can be set to a relatively low pressure, and the speed at which the piston 21 slides toward the oil storage chamber 23 can be slowed down.

In this state, the third throttle oil passage 26
The pressure oil that has flowed into the spring chamber 12 through the piston 21
The pressure oil that has flowed from the oil storage chamber 23 into the spring chamber 12 via the oil passage 27 due to the sliding displacement is throttled by the fourth throttle oil passage 28, A pressure P4 is generated depending on the flow rate.

Here, the main valve body 16 receives a force (P1×S1) acting rightward in FIG. 2 and a force acting leftward (P1×S1).
P2 × S2 + P4 × (S4 - S2 ) + F1
) is disrupted as the primary side pressure P1 increases, and the main valve body 16 at time T2, as illustrated in FIG.

[0029]

[Equation 2] P1 × S1 > P2 × S2 + P4 × (S4 − S2 ) + F1, and the valve seat member 13 is separated from the main valve seat 13A and the valve is opened.

While the piston 21 is slidingly displaced toward the oil storage chamber 23, the pressure P2 in the first pressure chamber 20 is reduced by the first, second, and third throttle oils, as described above. Road 24
, 25, 26, determined by the flow rate of pressure oil flowing through , 25, 26,
The pressure P4 in the spring chamber 12 is determined by the flow rate of the pressure oil flowing into the spring chamber 12 via the third throttle oil passage 26 and the piston 21.
The flow rate of the pressure oil that flows from the oil storage chamber 23 into the spring chamber 12 via the oil passage 27 due to the sliding displacement of . The right side of Equation 2 is constant, and the main valve body 16 maintains the primary side pressure P1 at a constant pressure P until time T3 in FIG.
Continue low pressure relief as L. In this case, by making the fourth throttle oil passage 28 smaller, the pressure P in the spring chamber 12 can be reduced.
4 can be set to a high pressure, and the primary side pressure P1 can be adjusted to a desired constant pressure PL as illustrated in FIG.

Next, when the piston 21 slides within the guide member 15 and comes into contact with the bottom surface of the annular portion 15B, the pressure P3 in the second pressure chamber 22 rises rapidly, and the pressure P3 in the first pressure chamber 20 increases. Therefore, the force acting on the sub-valve body 18 to the right is (P2 × S2 ), the force acting to the left is (P3 × S3 + F2 ), and the spring load F2 of the weak spring 19 can be ignored. Assuming that,

[0032]

[Math. 3] P2 ×S2 < P3 ×S3, the sub-valve body 18 is seated on the valve seat 16A of the main valve body 16, and the main valve body 16
and become displaced together. In this state, the third throttle oil passage 26 is again blocked off from the spring chamber 12 as shown in FIG. 2, so the pressure P2 in the first pressure chamber 20 becomes equal to the primary pressure P1.

[0033] At this point, the third throttle oil passage 26 is shut off,
Since the piston 21 is also stopped, the pressure P4 in the spring chamber 12 becomes a negligible value, the force acting on the main valve body 16 leftward is (P3 × S3 + F1), and the force acting rightward is (P1 × S1), and the main valve body 1
The balance of forces acting on 6 is P1 = P2 = P3
In the state of

[0034]

[Equation 4]P1×S1<P3×S3+F1, the main valve body 16 seats on the main valve seat 13A of the valve seat member 13, and closes again at time T3 in FIG.

Then, the primary side pressure P1 increases due to the closing of the main valve body 16, and in this case as well, the third throttle oil passage 26 is blocked and the piston 21 is stopped, so the pressure P1 increases.
, P2 and P3 are approximately P1 = P2 = P3
However, since the pressure receiving areas S1 and S3 satisfy S1 > S3, when the product of the pressure P1 and the pressure receiving area (S1 - S3) becomes larger than the spring load F1, the main valve body 1
6 is

[0036]

[Equation 5] The valve opens again based on the relationship P1 ×S1 > P3 ×S3 +F1, and as shown in FIG.
After a short time TL from TL, the primary side pressure P1 is high-pressure relieved.

Therefore, in this embodiment, the primary side pressure P1 in the main pipe 4A can be controlled as shown by the solid line in FIG. Pressure is generated, which may cause the main pipe 4A and hydraulic equipment such as the hydraulic motor 1 to vibrate, malfunction, or
Damage to the hydraulic motor 1 can be prevented, and the hydraulic motor 1 can be started smoothly. In addition, the directional control valve 5 is moved to the neutral position (
When switching from the switching position (a) to the switching position (c), similar effects can be obtained by the crossover relief valve 10.

On the other hand, when returning the directional switching valve 5 from the switching position (B) to the neutral position (A) and stopping the hydraulic motor 1, after the counterbalance valve 7 returns to the neutral position (A), The crossover relief valve 10 can be operated in substantially the same manner as in the case described above, and in this case, the pressure in the main conduit 4B due to the inertial rotation of the hydraulic motor 1 is applied to the main valve body after the sub-valve body 18 is opened. By opening the valve 16, it is possible to provide relief to the main pipe 4A side, which is the low pressure side, via the branch pipe 8B, and to apply braking force to the hydraulic motor 1.
The generation of peak pressure can also be prevented. Further, even when the directional switching valve 5 is returned from the switching position (c) to the neutral position (a), the crossover relief valve 9 can be operated in the same manner.

Furthermore, in this embodiment, there is no need to provide a pressure increase relief valve or the like in the brake valve 6 separately from the crossover relief valves 9 and 10, and it is possible to prevent the overall structure of the brake valve 6 from becoming complicated and large. , the whole can be formed compactly and miniaturized.

In the above embodiment, the third throttle oil passage 26 is provided diagonally in the head 18B of the sub-valve body 18, but the present invention is not limited to this. 16
A third throttle oil passage is drilled in the opening, and when the sub-valve body 18 is unseated from the valve seat 16A of the main valve body 16, the first pressure chamber 20 and the spring chamber 12 are connected through this throttle oil passage. They may be communicated.

Further, in the above embodiment, the valve body 11 and the valve seat member 13 are formed separately, but instead of this, it is possible to form the valve seat member 13 integrally with the valve body 11 in advance. You can also do this.

[0042]

Effects of the Invention As detailed above, according to the present invention, the auxiliary valve body is provided so as to be slidable on the guide member, and the auxiliary valve body is mounted on and off the main valve body.
A first pressure chamber is defined between the sub-valve body and the main valve body, a second pressure chamber is defined between the sub-valve body and the guide member, and a second pressure chamber is defined between the sub-valve body and the main valve body.
When the sub-valve body is separated from the main valve body, the pressure in the first pressure chamber is guided to the spring chamber through the third throttle oil passage, and the pressure in the first pressure chamber is communicated with the spring chamber through the third throttle oil passage. Since it communicates with the next side through the fourth throttle oil passage bored in the valve body, when the pressure on the primary side of the hydraulic circuit increases rapidly, the sub-valve element is opened and the valve is opened for a certain period of time. The main valve element can be opened at low pressure, eliminating shock and preventing the generation of peak pressure.Afterwards, it can be operated in the same way as a normal pressure control valve, preventing damage to pipelines and hydraulic equipment. can. By appropriately changing the flow area of the fourth throttle oil passage, the low pressure relief pressure can be adjusted without affecting the low pressure relief time.

Furthermore, by providing the piston within the guide member, the second pressure chamber can be enlarged and the closing timing of the main valve body can be delayed as appropriate, and the generation of the peak pressure can be more effectively prevented. can.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view of the crossover relief valve in FIG. 1;

FIG. 3 is a characteristic diagram showing the relationship between primary side pressure and time.

[Explanation of symbols]

1 Hydraulic motor 2 Hydraulic pump 3 Tanks 4A, 4B Main pipeline 5 Directional switching valve 6 Brake valves 9, 10 Crossover relief valve (pressure control valve) 1
1 Valve body 11A Main valve body sliding hole 12 Spring chamber 13 Valve seat member 13A Main valve seat 15 Guide member 16 Main valve body 17 Pressure setting spring 18 Sub-valve body 20 First pressure chamber 21 Piston 22 Second pressure Chamber 24 First throttle oil passage 25 Second throttle oil passage 26 Third throttle oil passage 28 Fourth throttle oil passage

Claims (2)

[Claims] Claim 1: A valve body consisting of a cylindrical body, with a main valve seat on one side and a spring chamber on the other side across a main valve body sliding hole formed in an axially intermediate portion, and a main body of the valve body. A main valve body slidably inserted into a valve body sliding hole, and a pressure setting device disposed within a spring chamber of the valve body to urge the main valve body to seat on the main valve seat. a spring; a cylindrical guide member provided on the spring chamber side of the valve body; a sub-valve body, the other side of which is slidably inserted into the guide member and defines a second pressure chamber having a larger pressure-receiving area than the first pressure chamber; A first throttle oil passage is provided in the main valve body so as to guide the primary side pressure acting on the main valve body to a first pressure chamber, and A second throttle oil passage is formed in the sub-valve body so as to lead to the pressure chamber, and when the sub-valve body is separated from the main valve body, the pressure in the first pressure chamber is transferred to the valve body. A pressure system consisting of a third throttle oil passage leading to the spring chamber of the valve body, and a fourth throttle oil passage bored in the valve body to communicate the spring chamber of the valve body with the secondary side. control valve. 2. The pressure control valve according to claim 1, wherein a piston is slidably provided within the guide member to enlarge a second pressure chamber defined by the sub-valve body.