JP2001200807A - Holding valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the switching operation of a valve poppet using a solenoid smaller in size than that of a regular type in a holding valve of a type switched directly by a solenoid. SOLUTION: In holding valves 1a and 1b of a type switched directly by solenoids 11a and 11b, flow paths 14 and 15 leading from one input/output port 2 or 3 through a valve seat 5 to the other input/output port 3 or 2 is separated from a drain chamber 16 positioned at the tip by both end parts and the valve seat 5 while maintaining oiltight both end parts of a valve poppet 6 of a valve sleeve 4. In addition, the outer diameter dimensions of the valve seat 5 and the valve poppet 6 at both end parts thereof are made equal to each other so as to form a same pressure receiving area. Then, the solenoids 11a and 11b are allowed to communicate with a drain chamber 16 on the tip side through a through-hole 18 provided in the valve poppet 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening / closing operation in conjunction with on / off control of a solenoid associated with a switching operation of a hydraulic drive device between an operation and a stop, and a load being kept unchanged by a closing operation by stopping the hydraulic drive device. The present invention relates to an improvement in a holding valve provided with a holding function for maintaining the holding valve in a state.

[0002]

2. Description of the Related Art Conventionally, as a holding mechanism for maintaining a load as it is when a hydraulic drive is stopped, for example, as disclosed in Japanese Patent Application Laid-Open No. 2-255005, It is known that a holding valve, which sometimes keeps a load while maintaining a closed state, is opened using a pilot pressure generated by a throttle mechanism at the same time as the start of operation of the hydraulic drive device.

[0003] In addition, Japanese Patent Application Laid-Open No. 62-28870
As disclosed in Japanese Patent Application Laid-Open No. H06-2294, the sub-valve is switched by a solenoid at the same time as the operation of the hydraulic drive device is started, and the pilot pressure is applied to the holding valve by the sub-valve to be released. It is also known that a holding valve is pushed and opened directly by a solenoid at the same time as the start of operation of a hydraulic drive device.

[0004]

However, in the system in which the holding valve is opened by using the pilot pressure as in the above-mentioned Japanese Patent Application Laid-Open No. 2-255005, the pilot pressure is set by mounting a throttle mechanism. Even if the pressure is increased until the pressure reaches the required pressure, the pilot pressure may not be able to increase sufficiently depending on the operating conditions.Therefore, the holding valve may hunt due to the balance with the return pressure. Therefore, the operation of the hydraulic drive device may be unstable.

On the other hand, Japanese Patent Application Laid-Open No. Sho 62-288702 discloses
In the publication, the solenoid is excited to open the pilot valve by switching the sub-valve to apply the pilot pressure to the holding valve, thereby eliminating the possibility that the operation of the hydraulic drive device becomes unstable.
If the circuit pressure does not exceed the cracking pressure even if the solenoid is excited, the holding valve will not open unless the circuit pressure exceeds the cracking pressure of the holding valve.

[0006] In this respect, in Japanese Unexamined Patent Publication No. 6-294149, since the holding valve is directly opened by the solenoid, it is possible to easily solve the above two problems. Although it is excellent in that it can be done, however, the solenoid becomes large because it requires not only the return spring force to open the holding valve but also the suction force that overcomes the oil pressure acting on the valve poppet of the holding valve Problem.

Therefore, an object of the present invention is to switch a valve poppet by using a small-sized solenoid only by applying a suction force that overcomes a return spring force, irrespective of the hydraulic pressure acting on the valve poppet with respect to the solenoid. It is an object of the present invention to provide a direct switching type holding valve using a solenoid.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a valve sleeve having a pair of input / output ports, which is connected to and separated from a valve seat provided on the inner surface of the valve sleeve. In a direct switching type holding valve in which a valve poppet for intermittently controlling communication of a valve is slidably inserted and the valve poppet is controlled to be opened and closed by a restoring force of a return spring and a driving force by a solenoid, both ends of the valve poppet are With both ends of the valve poppet and the valve seat keeping the parts oil-tight, a flow path from one input / output port to the other input / output port through the valve seat and the drain chamber located at the tip are partitioned, and The outer diameter of both ends of the valve seat and the valve poppet must be equal, and the valve poppet It is accomplished by communication with the body of the solenoid to drain chamber of the distal end side through holes bored in.

In other words, with the construction described above, the holding valve of the present invention excites the solenoid so that the valve poppet receives a force from the solenoid, overcomes the restoring force of the return spring, and closes the valve seat on the valve sleeve side. Open to allow the flow of pressure oil from one input / output port to the other input / output port in the valve sleeve.

Conversely, when the solenoid is de-energized and switched to the non-excited state, the valve poppet is pushed back by the restoring force of the return spring to close the valve seat on the valve sleeve side, and one of the input / output ports from the other input / output port. The flow of the pressure oil that is going to return to the input / output port is cut off to maintain the load.

On the other hand, at the time of the above operation, the solenoid portion communicates with the drain chamber on the opposite side through a through hole formed in the valve poppet, and a flow path that communicates the pair of input / output ports with each other. Even if the high-pressure oil acts on one or both of them regardless of the opening / closing of the valve seat, the pressure receiving areas of the valve poppet are kept equal to each other.

As a result, the hydraulic pressure does not exert any influence on the switching operation of the valve poppet by the on / off control of the solenoid, and therefore, unlike the above-mentioned other conventional type of holding valve, the holding pressure is not affected. Not only can the valve prevent hunting or the passage pressure loss from becoming unnecessarily large, but also a large solenoid with a suction force that overcomes the oil pressure acting on the valve poppet of the holding valve. Problems such as necessity can be solved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereafter, a direct switching type holding valve 1a, 1 using a solenoid of the present invention will be described.
Prior to the description of the embodiment b, an example of using these holding valves 1a and 1b will be described first with reference to FIG. 2 in order to facilitate understanding of the contents of the invention.

As shown in FIG. 2, the solenoid direct switching type holding valves 1a and 1b according to the present invention are provided.
Are a fixed displacement pump 22 and a reservoir 23, which are rotated forward and reverse by an electric motor 21, and a check valve 24a,
24b and the hydraulic cylinder 25.

That is, the holding valves 1a, 1
b is the solenoid 11a,
11b is switched to the open state by the excitation of
The electric motor 21 selectively rotates the fixed displacement pump 22 in either the forward or reverse direction.

Accordingly, the fixed displacement pump 22 supplies the hydraulic oil in one of the hydraulic oil chambers 25a, 25b of the hydraulic cylinder 25 to the circuits 26a, 26b in accordance with the rotation direction at that time.
Holding valve 1 switched from open to open
a, 1b.

Subsequently, the hydraulic oil sucked into the fixed displacement pump 22 pushes and opens the holding valves 1b and 1a before switching from the circuits 27b and 27a on the opposite side to the hydraulic circuit 25 on the opposite side. Hydraulic oil chamber 25b,
25a, and the hydraulic cylinder 25 is selectively operated in both forward and reverse directions.

A circuit 28 shown by a broken line is provided for storing hydraulic fluid leaking from the inside of the holding valves 1a and 1b into the reservoir 2a.
3 is a drain circuit for collecting to 3
The circuits 29a and 29b include check valves 24a and 24b.
This is for opening the check valves 24a and 24b from the reservoir 23 and replenishing the hydraulic oil that has become insufficient due to the above-described internal leakage to the suction side.

Next, an embodiment which is a specific configuration example of the direct switching type holding valves 1a and 1b using the solenoid of the present invention will be described with reference to FIG.

The holding valves 1a and 1b are connected to and separated from a valve seat 4 provided on the inner surface of the valve sleeve 4 with respect to the inside of a valve sleeve 4 having a pair of input and output ports 2 and 3, so that the input and output ports 2 and 3 are separated. , 3 is provided with a slidable valve poppet 6 for intermittently controlling the communication between the valves.

The valve sleeve 4 is attached to the port block 9 by screwing the input / output port 2 to the pump ports 7a and 7b and the input / output port 3 to the cylinder ports 8a and 8b.

The pump ports 7a and 7b are connected to the fixed displacement pump 22 as shown in FIG.
7b and the cylinder ports 8a, 8
b is also passed through the circuits 26a and 26b to the hydraulic cylinder 2
5 to one or the other of the hydraulic oil chambers 25a, 25b.

At the base end of the valve sleeve 4 in the holding valves 1a, 1b, solenoids 11a, 1b are provided.
Solenoids 11a and 11b are attached so that their axes are aligned by screwing and connecting body portion 10 of 1b.

Inside the body part 10 of the solenoids 11a and 11b screwed to the valve sleeve 4,
A base end side of the valve poppet 6 is slidably inserted and guided with a labyrinth groove 12 for restricting hydraulic oil leakage, and a distal end side of the valve poppet 6 is sealed with the valve sleeve 4 by a seal 13. Are in sliding contact with each other.

Both end portions of the valve poppet 6 having the labyrinth groove 12 and the seal 13 interposed therebetween are provided with a flow path 14 for connecting the input / output ports 2 and 3 to each other through the valve seat 5 between the valve sleeve 4 and the valve poppet 6. , 15, and a drain chamber 16 is defined by the tip of the valve poppet 6 and the port block 9.

The return spring 1 is provided between the valve poppet 6 and the port block 9 inside the drain chamber 16.
And a push rod extending from an iron core 19 of each of the solenoids 11a and 11b through a through hole 18 formed through the valve poppet 6 to communicate the solenoids 11a and 11b with the drain chamber 16 on the distal end side. 2
At 0, the valve poppet 6 can be pushed against the return spring 17.

Furthermore, in this case, the outer diameters of both end portions of the valve seat 5 and the valve poppet 6 are made equal, and the pressure receiving areas of these two portions are made equal to balance the oil pressure acting on the valve poppet 6. I try to make it.

Thus, the direct switching type holding valves 1a and 1b using the solenoids 11a and 11b of FIG. 1 according to the embodiment of the present invention operate as follows.

In the holding valve 1a, 1b according to the present invention having the above-described structure, the solenoid 11a or 11b is excited so that the iron core 19 receives the magnetic force, passes through the push rod 20, and the valve poppet 6 has the return spring at the tip. Push against the restoring force of 17.

As a result, the valve seat 5 of the valve sleeve 4 which has been closed by the valve poppet 6 is opened, and the pump 14 is moved from the cylinder port 8 a of the port block 9 through the input / output ports 2 and 3 by the flow paths 14 and 15 of the valve sleeve 4. The suction oil flowing to the port 7a and the flow of the pressure oil flowing from the pump port 7b to the cylinder port 8b are allowed.

From this, the holding valves 1a, 1b which are on the suction side of the hydraulic oil at that time in accordance with the rotation direction of the fixed displacement pump 22 in the hydraulic drive device of FIG.
It is assumed that the solenoids 11a and 11b are selectively excited.

Then, the valve poppet 6 of the holding valve 1a or 1b on the suction side is pushed and opened by the push rod 20 against the return spring 17, and in FIG. 2, the holding valve 1a or 1b is opened.
b is switched to the right position, and one of the hydraulic oil chambers 25a, 25b of the hydraulic cylinder 25 is pumped by the circuit 26a, 27a or 26b, 27b according to the rotation direction of the fixed displacement pump 22 at that time.

The pumped hydraulic oil is supplied to the circuit 26.
b, 27b or 26a, 27a to open the valve poppet 6 of the holding valve 1b or 1a against the return spring 17 and to open the hydraulic cylinder 2
5 to one of the hydraulic oil chambers 25b or 25a to selectively operate the hydraulic cylinder 25 in both forward and reverse directions.

Conversely, when the excitation of the solenoid 11a or 11b is turned off and switched to the non-excitation state,
9 is released, and the valve poppet 6 is pushed back by the restoring force of the return spring 17.

As a result, the valve poppet 6 is pressed against the valve seat 5 on the valve sleeve 4 side by the restoring force of the return spring 17, and closes the valve seat 5 to move the pump port 7a from the cylinder ports 8a, 8b of the port block 9. , 7b is cut off, and the hydraulic cylinder 25, which is the load, is maintained at the current state.

Further, in the above description, the solenoids 11a and 11b of the holding valves 1a and 1b communicate with the drain chamber 16 on the opposite side through a through hole 18 penetrating through the valve poppet 6. The flow path which communicates the input / output ports 2 and 3 with each other, regardless of whether the high pressure oil acts on one or both of them regardless of the opening / closing of the valve seat 5, the pressure receiving pressure of the pressure oil acting on both end faces of the valve poppet 6. The areas are kept equal to each other.

Therefore, when the valve poppet 6 is switched by the on / off control of the solenoids 11a and 11b, the hydraulic pressure does not exert any influence, so that the holding valve is different from other types of holding valves. A large solenoid having a suction force capable of preventing hunting or unnecessary increase in passage pressure loss by itself and preventing hydraulic pressure acting on the valve poppet 6 of the holding valves 1a and 1b. Can be solved.

In the embodiment shown in FIG. 1, in forming the holding valves 1a and 1b, the valve sleeve 4 is divided into a proximal end sleeve 4a and a distal end sleeve 4a.
The base-side sleeve 4a and the distal-side sleeve 4b are connected to each other by the spigot 30 while maintaining the concentric state.

Thus, not only can the valve sleeve 4 be integrated with the valve sleeve 4 while maintaining the concentricity of the proximal and distal sleeves 4a and 4b with a simple structure, but also the valve poppet can be inserted into the valve sleeve 4. 6 is also easy to incorporate.

Further, in this embodiment, the body parts 10 of the solenoids 11a and 11b are fixedly fitted to the inner surface of the valve sleeve 4, and these body parts 1
The slide valve is inserted slidably into the inside of the valve poppet 6 through a labyrinth groove 12 provided on the base end side of the valve poppet 6, so that the holding valves 1a and 1b of the direct switching type using the solenoids 11a and 11b can be formed with a simple configuration. It was possible to do it.

[0041]

As described above, according to the first aspect of the present invention, in a holding valve of a direct switching type using a solenoid, both ends of the valve poppet are connected to the valve while keeping both ends of the valve poppet oil-tight. The seat divides a flow path from one input / output port to the other input / output port through the valve seat and a drain chamber located at the tip, and equalizes outer diameters at both end portions of the valve seat and the valve poppet. In addition, the hydraulic pressure exerts no influence on the switching operation of the valve poppet by controlling the solenoid on / off by connecting the solenoid part to the drain chamber on the tip side with the through hole drilled in the valve poppet. Which allows for a haunch like a similar holding bal with other formats Of the holding valve can be prevented and the pressure loss of the passage can be prevented from becoming unnecessarily large, as well as a large size having a suction force that overcomes the oil pressure acting on the valve poppet of the holding valve. This eliminates the need for a solenoid.

Further, in constituting the holding valve as in the second aspect of the invention, the valve sleeve is divided into two members, a proximal end sleeve and a distal end sleeve, and these proximal end sleeve and distal end sleeve are separated. Since the concentric body is joined by the spigot, in addition to the effect of the first aspect of the present invention, it is possible to maintain the concentricity of the proximal and distal sleeves with a simple structure while maintaining the concentricity of the valve sleeve. Not only can be secured, but also the valve poppet can be easily incorporated into the valve sleeve during production.

Further, according to the third aspect of the present invention, the solenoid is inserted and fixed to the inner surface of the valve sleeve, and the base end portion of the valve poppet is slidably inserted into the solenoid. In addition to the effects of the first and second aspects of the present invention, a direct switching type holding valve using a solenoid can be provided with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of a solenoid direct switching type holding valve according to the present invention.

FIG. 2 is a circuit diagram showing an example of use of the above holding valve.

[Explanation of symbols]

 1a, 1b Holding valve 2, 3 Input / output port 4 Valve sleeve 4a Base end sleeve 4b Distal end sleeve 5 Valve seat 6 Valve poppet 10 Body part of solenoid 11a, 11b Solenoid 12 Labyrinth groove 13 Seal 14, 15 Flow path 16 drain Chamber 17 Return spring 18 Valve poppet through hole 30 Inlay

Continued on the front page (72) Inventor Keiji Saito 2-4-1 Hamamatsucho, Minato-ku, Tokyo Inside World Trade Center Building Kayaba Kogyo Co., Ltd. (72) Inventor Kosuke Sato 2-4-1 Hamamatsucho, Minato-ku, Tokyo No. World Trade Center Building Kayaba Industry Co., Ltd. F-term (reference) 3H089 BB27 CC01 DA02 DA14 DB44 DB48 DB73 DB76 EE31 GG02

Claims (3)

[Claims] An inside of a valve sleeve having a pair of input / output ports is slidably provided with a valve poppet which is connected to and separated from a valve seat provided on an inner surface of the valve sleeve to control intermittent communication between the pair of input / output ports. And a direct switching type holding valve in which the opening and closing of the valve poppet is controlled by the restoring force of the return spring and the driving force of the solenoid, the both ends of the valve poppet are kept oil-tight while both ends of the valve poppet are kept oil-tight. The portion and the valve seat define a flow path from one input / output port to the other input / output port through the valve seat and a drain chamber located at the tip, and an outer diameter at both end portions of the valve seat and the valve poppet. Equalize the dimensions and open the solenoid body first with a through hole in the valve poppet. A holding valve, which communicates with the drain chamber on the end side. 2. A valve having an integral structure, wherein a valve sleeve is divided into two members, a proximal side sleeve and a distal side sleeve, and the proximal side sleeve and the distal side sleeve are connected to each other while being kept concentric by spigots. The holding valve according to claim 1, wherein the holding valve is configured as a sleeve. 3. The holding valve according to claim 1, wherein a solenoid is inserted into and fixed to an inner surface of the valve sleeve, and a base end portion of the valve poppet is slidably inserted into the solenoid.