JPH10332021A - Solenoid direction switching valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid direction switching valve having a means releasing a spool sticking to a fitting hole of a valve block. SOLUTION: In a solenoid direction switching valve constituted by a hole fitting a spool, valve block 1 formed with a plurality of ports, spool 5, and a pair of solenoids 10, 20 provided in the right/left of the valve block 1, changing a position of the spool 5 by on/off turning the solenoid 10, 20, and switching a direction of operating oil, between the valve block 1 and a movable core 13, 23 of the right/left solenoid 10, 20, a pair of compression springs 30a, 30b are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic directional control valve capable of releasing the sticking of a spool.

[0002]

2. Description of the Related Art The structure of an electromagnetic directional switching valve will be described with reference to FIG. FIG. 4 shows a longitudinal sectional view when the spool is at the neutral position. 1 is a valve block. Valve block 1
Are formed with a fitting hole 2 of a spool, a flow path 3 and a port 4 which is an oil inlet / outlet. Reference numeral 5 denotes a spool fitted in the fitting hole 2, and reference numerals 6a and 6b denote push rods, one end of which contacts the end of the spool 5, and the other end protrudes toward the solenoid. Centering springs 7a, 7b are interposed between the end of the spool 5 and the valve block wall, and the centering springs 7a, 7b hold the spool 5 in the neutral position when the solenoid is de-energized.

[0003] Solenoids 10, 2
0 is provided. The solenoid 10 includes a coil 11,
It comprises a fixed iron core 12, a movable iron core 13 and a cover 14. The movable iron core 13 is attached to the cylindrical hole 15 surrounded by the coil 11 so as to be able to enter and exit. Solenoid 2
Numeral 0 includes a coil 21, a fixed iron core 22, a movable iron core 23, and a cover 24. The movable iron core 23 has, like the solenoid 10, a cylindrical hole 25 surrounded by the coil 21.
It is installed so that it can enter and exit.

When the solenoid 10 is excited, the movable iron core 1
Numeral 3 is attracted to the fixed iron core 12, moves to the left, and moves the spool 5 to the left via the push rod 6a. The spool 5 compresses the centering spring 7b and pushes the push rod 6b to the left. Thus, the P port (pump port) communicates with the B port, and the A port communicates with the T port (tank port) (see FIG. 5).

When the solenoid 20 is excited, the movable iron core 2
3 is attracted to the fixed iron core 22 and moves rightward, and moves the spool 5 rightward via the push rod 6b. The spool 5 compresses the centering spring 7a and pushes the push rod 6a to the right. As a result, the P port (pump port) communicates with the A port, and the B port communicates with the T port (tank port).

In the above-described electromagnetic directional control valve, during use, dust is clogged in the gap between the spool 5 and the wall of the fitting hole 2 and the spool is fixed to the wall of the fitting hole so that switching cannot be performed. Failure occurs. In such a case, a maintenance man goes to the electromagnetic directional control valve and pushes a manual operation push pin (not shown) outside the solenoid cover to apply a force to the spool via the movable iron core and the push rod. Adding or hitting the outside of the valve block to give an impact has released the sticking of the spool.

[0007]

However, the conventional method of releasing and fixing the spool has the following problems. (1) The maintenance man has to go to the side of the failed electromagnetic directional control valve and operate the push pin for manual operation, which requires time and labor. (2) Since the user directly touches the electromagnetic directional control valve, a safety problem may occur. (3) If an impact is given by hitting the valve block, the valve block may be flawed, and may cause malfunction of the electromagnetic directional switching valve.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide an electromagnetic directional control valve capable of releasing the sticking of a spool remotely.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to provide a valve block having a hole into which a spool fits and a plurality of ports, and a pair of solenoids provided on the left and right sides of the spool and the valve block. An electromagnetic directional control valve that changes the position of a spool by on-off to change the direction of hydraulic oil is achieved by an electromagnetic directional control valve provided with a pair of compression springs between a valve block and movable iron cores of left and right solenoids.

[0010] Since a pair of compression springs are provided between the valve block and the movable iron cores of the left and right solenoids, the movable iron core is demagnetized by demagnetizing the solenoids regardless of the position of the spool. Can be returned to neutral position.
Accordingly, the left and right solenoids can be alternately excited to repeatedly apply an impact to the spool. Thereby, the fixation can be released.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the electromagnetic directional control valve of the present invention. This figure shows a state in which the spool 5 is in the neutral position without energizing the left and right solenoids 20, 10. The spool 5 is fitted in the fitting hole 2 of the valve block 1. One end of the push rod 6 a contacts the center of the right end of the spool 5, and the other end penetrates the right wall of the valve block 1 and protrudes into a cylindrical hole 15 surrounded by the coil 11. Another push rod 6 b is in contact with the center of the left end of the spool 5, and the other end penetrates the left wall of the valve block 1 and is inside another cylindrical hole 25 surrounded by the coil 21. It protrudes.

A centering spring 7a is provided between the right end of the spool 5 and the right wall of the valve block 1. Also,
Another centering spring 7b is provided between the left end of the spool 5 and the left wall of the valve block 1. Coil 11
A fixed iron core 12 is provided on the outer periphery of the cylinder, and a movable iron core 13 is attached to a cylindrical hole 15 surrounded by the coil 11 so as to be movable left and right. Similarly, a fixed iron core 22 is provided on the outer periphery of the coil 21, and a movable iron core 23 is attached to a cylindrical hole 25 surrounded by the coil 21 so as to be movable left and right.

In the directional control valve of the present invention, the cylindrical hole 1
A compression spring 30 a is provided between the right end of the valve block 1 in 5 and the movable iron core 13, and a compression spring 30 b is provided between the left end of the valve block 1 in the cylindrical hole 25 and the movable iron core 23. Therefore, when the solenoid 10 is excited and the movable iron core 13 is moved to the left, the spool 5 is moved from the neutral position to the left position while compressing the compression spring 30a. Also, if the solenoid 20 is excited and the movable iron core 23 is moved to the right, the spool 5 is moved from the neutral position to the right position while compressing the compression spring 30b.

Next, the operation of the compression springs 30a and 30b will be described. Now, as shown in FIG.
Is excited to move the movable iron core 13 to the left, and the spool 5 is switched to the left position. In this case, the compression spring 30a
If there is no, the solenoid 10 is demagnetized and the solenoid 20
, The movable iron core 13 remains in contact with the fixed iron core 12 because the spool 5 cannot be moved to the right. In this state, even if the solenoid 10 is excited, the movable iron core 13 cannot be moved to the left (see FIG. 5).

On the other hand, in the directional control valve of the present invention, while the solenoid 10 is energized, the compression spring 30a
Are compressed to store the force to push the movable iron core 13 back to the right. Therefore, when the solenoid 10 is demagnetized, the compression spring 3
0a pushes the movable iron core 13 back to the neutral position on the right side (the position when the spool 5 is neutral) (see FIG. 3).

If the spool 5 is stuck and does not move after the spool 5 is switched to the right position, the compression spring 30b is provided. Push back to neutral position (position when spool 5 is neutral).

That is, in the directional control valve of the present invention, when the solenoid is demagnetized regardless of the position of the spool 5, the movable iron core returns to the position where the spool is in the neutral position (see FIG. 1).

The release of the fixed spool is performed as follows. (1) Demagnetize the energized solenoid to bring the movable iron core to the neutral position (see FIG. 1). (2) One of the solenoids 10 is excited to move the movable iron core 13 and to give an impact to the spool 5 via the push rod 6a. The solenoid 10 is demagnetized. (3) The other solenoid 20 is excited to move the movable iron core 23 and give an impact to the spool 5 via the push rod 6b. The solenoid 20 is demagnetized. (4) (2) and (3) are alternately repeated until the fixation is released.

The above operation is performed on a control panel located away from the direction switching valve.

[0021]

According to the present invention, since a pair of compression springs are provided between the valve block and the movable iron core, the movable iron cores on both sides are moved to the neutral position regardless of the position where the spool is fixed. Therefore, the left and right solenoids are alternately excited to give an impact to the spool, thereby releasing the sticking.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a solenoid-operated directional control valve of the present invention at a neutral position.

FIG. 2 is a longitudinal sectional view when the right solenoid of the electromagnetic directional switching valve of the present invention is excited.

FIG. 3 is a longitudinal sectional view showing a state where the movable iron core returns to a neutral position by a compression spring in the electromagnetic directional switching valve of the present invention.

FIG. 4 is a longitudinal sectional view of a conventional electromagnetic directional control valve at a neutral position.

FIG. 5 is a longitudinal sectional view of a conventional electromagnetic directional control valve when a spool is fixed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve block 2 Fitting hole 3 Flow path 4 Port 5 Spool 6a, 6b Push rod 7a, 7b Centering spring 10, 20 Solenoid 11, 21 Coil 12, 22, Fixed iron core 13, 23 Movable iron core 15, 25 Cylindrical hole 30a, 30b compression spring

Claims (1)

[Claims] The present invention comprises a valve block having a hole into which a spool fits and a plurality of ports, and a pair of solenoids provided on the left and right sides of the spool and the valve block. And a pair of compression springs provided between the valve block and the movable iron cores of the left and right solenoids.