JPH0750617Y2 - Solenoid control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electromagnetic control valve.

[Conventional technology]

The electromagnetic control valve is provided, for example, in a drain pipe branched from the pressure oil supply oil passage from the pressure oil supply source to the hydraulic actuator, and adjusts the throttle of the inlet to the drain pipe to adjust the hydraulic actuator. Used to control the hydraulic pressure of the supply pressure oil.

In the electromagnetic control valve, an axial sliding hole is formed in the valve body, the sliding hole is provided with a pressure oil inlet and a pressure oil outlet, and the spool is slidably fitted in the sliding hole.
The spool is axially displaced by the joint operation of the solenoid and the compression coil spring.

When the solenoid is not energized, the spool
When the slit is at the axial position with zero opening, the communication between the pressure oil inlet and the pressure oil outlet is blocked, and when the solenoid is excited by the control current, the spool is generated by the magnetic force according to the control current. A displacement occurs in the axial direction, the slit opens, and the pressure oil inlet and the pressure oil outlet communicate with each other through the slit.

In the prior art, the opening area of the slit must be increased when the control current is applied, because the back pressure in the pressure oil supply oil passage must be reduced. Therefore, as shown in FIG. Rectangular slits B, B, B, B having a wide width with respect to the displacement direction in the axial direction are provided.

[Problems to be solved by the device]

Since the slit B formed on the spool of the electromagnetic pressure control valve in the above-mentioned conventional technique is a rectangle having a wide width with respect to the displacement direction of the spool A, at the start of slit opening, the slit B is spread over the entire width at the same time. Because it opens
The pressure fluctuation is large, and a large flow force acts on the slit portion as shown by the chain line in FIG. As a result, the spool vibrates, malfunctions occur, and pressure control becomes impossible.

[Means for Solving the Problems]

The electromagnetic control valve of the present invention has a sliding body, a valve body having a pressure oil inlet opening and a pressure oil outlet opening in the sliding hole, a spool slidably inserted in the sliding hole, and a sliding hole of the spool. It is composed of an electromagnetic means for controlling the axial displacement due to the magnetic force inside, and the spool has the first slit in the axial direction having a lateral width consisting of at least a minute width portion and a large portion and the minute width portion is removed from the first slit. A second axial slit having a large width is formed, and the slit is interposed in the communication path between the pressure oil inlet and the pressure oil outlet, and the pressure is changed by the axial displacement position of the spool. An opening degree from zero to full opening is given to the communication between the oil inlet and the pressure oil outlet, and at the start of opening, the spool is formed in a position direction in which only the minute width portion opens.

[Action]

In the solenoid control valve described above, when the solenoid is not excited, the spool has the slit in the axial direction position with zero opening, and the communication between the pressure oil inlet and the pressure oil outlet is blocked. When the solenoid is excited by the control current, the spool is displaced in the axial direction by the magnetic force corresponding to the control current, and the slit first opens the small lateral width portion of the first slit, and then the first slit. The large width portion of the slit opens and the second slit starts opening. The opening area of the slit is controlled by the control current.

Therefore, when the control current is applied, the opening area of the slit can be made larger by the large width portion, the back pressure in the pressure oil supply oil passage can be reduced, and the opening area of the slit at the start of opening the slit can be reduced. Becomes a large area after the first minute area and does not suddenly become a large area from zero, and the flow force acting on the spool acts by the openings of the first slit and the second slit that start in the front and rear. The flow force (shown by a broken line in FIG. 4) is superposed, that is, the shape shown by a solid line in FIG. 4 is obtained, which is flat and reduced with respect to the change of the opening stroke of the slit.

When the above electromagnetic control valve is provided in, for example, a drain pipe branched from the pressure oil supply oil passage from the pressure oil supply source to the hydraulic actuator, the throttle of the flow passage to the drain pipe is as follows. The hydraulic pressure of the hydraulic oil supplied to the hydraulic actuator is adjusted and controlled.

〔Example〕

 An embodiment of this invention will be described with reference to the drawings.

The electromagnetic control valve shown in FIG. 1 is provided, for example, in a drain pipe branching from a pressure oil supply oil passage from the pressure oil supply source to the hydraulic operating device, and controls the hydraulic pressure of the hydraulic oil supplied to the hydraulic operating device. It is used as a thing.

The up, down, left, and right directions in FIG. 1 will be referred to as up, down, left, and right directions in the following description.

A valve body 1 of an electromagnetic control valve is attached to a housing H of the hydraulic actuator.

The valve body 1 includes a first member 1a and a second member 1a from the left side in FIG.
The four members, that is, the member 1b, the third member 1c, and the fourth member 1d, are coaxially connected by screw connection, sleeve connection, or the like, and are integrally configured in a substantially cylindrical shape.
The large diameter screw holes 2 and the inner flange 3 of the first member 1a, the large diameter holes 4 of the first member 1a and the second member 1b, the second member 1b, the third member 1c The medium diameter hole 5 of the fourth member 1d and the small diameter screw holes 6 and the small diameter holes 7 of the fourth member 1d are sequentially formed in sequence, and the large diameter screw hole 2 is connected to a drain pipe line, A union 9 having a through hole 8 formed therein is attached to the center hole of the side flange 3, a valve sleeve 10 is fitted in the large diameter hole 4, and the center hole of the valve sleeve 10 and the medium diameter hole 5 are A continuous sliding hole 11 having the same diameter is formed. The spool 12 is fitted in the sliding hole 11 and the valve sleeve
It is slidable between the stopper portion 13 at the left end of 10 and the step portion 14 between the medium diameter hole 5 and the small diameter screw hole 6.

An annular groove 15 is formed in the middle of the large-diameter hole 4, and the annular groove 15
The inflow passage 16 is formed radially from the bottom of the
The open end of the valve is an attachment part of the valve body 1 to the housing H. In the middle of the sliding hole 11 of the valve sleeve 10,
An annular groove 17 is formed, an inflow passage 18 is formed in the radial direction from the bottom of the annular groove 17, and opens toward the annular groove 15 of the valve body 1.

The spool 12 has a hollow hole 19 on the left and a stepped hole on the right.
20 and a central hole 21 that connects the two and a through hole 22 that is branched from the central hole 21 in the radial direction are formed.

A lid plug 23 is fitted into the small diameter hole 7 of the valve body 1 and is closed. The inner end of the lid plug 23 is threadedly engaged with the small-diameter screw hole 6 by being connected to the threaded portion 23a, and the outer end is also threadedly engaged with the threaded portion 23b to project to the outside of the valve body, and the nut 25 is threadedly engaged. There is. Stepped hole of spool 12 whose left end face abuts stopper 13
Between the bottom of the 20 and the tip of the screw part 23a, the compression coil spring 2
6 is fitted with preload. By rotating the outer end of the lid plug 23 to adjust and rotate the screw portion 23a with respect to the small-diameter screw hole 6, the lid plug 17 advances and retreats with respect to the spool 12, and the preload of the compression coil spring 26, that is, the initial pressure of the electromagnetic control valve. The O-ring 27 maintains the sealing property of the movable lid plug 23.

The second member 1b, the third member 1c and the fourth member 1b are provided on the outer circumference of the valve body 1.
A solenoid 28 is attached so as to surround the member 1d via a sleeve 24, and a cup-shaped solenoid cover 29 is surrounded on the outer periphery of the solenoid 28.
The right end face of 29 is inserted into the threaded portion 23b of the lid plug 15 and the nut 2
It is fastened to the right end surface of the valve body 1 by means of 5. The nut 18 also serves as a lock nut for the threaded portion 17a.

The solenoid 28 is supplied with an exciting current corresponding to a desired hydraulic pressure state of the pressure oil supplied to the hydraulic actuator.

At least the second member 1b, the spool 12, the fourth member 1d, and the solenoid cover 29 of the valve body 1 are magnetic bodies, and the third member 1c, the sleeve 24, and the compression coil spring 26 are non-magnetic bodies.

Therefore, when the solenoid 28 is excited, the valve body 1
Second member 1b, spool 12, end surface of spool 12, step portion 1
4, a magnetic circuit limited to the fourth member 1d and the solenoid cover 29 is configured.

As shown in FIG. 2, a rectangular portion 30 having a large slit width from the end edge side is provided on the end peripheral wall of the hollow hole portion 19 on the left side of the spool 12.
a, a chevron portion 30b having a gradually decreasing slit width, a first slit 30 having a shape in which a projection portion 30c having a small slit width is connected, and a chevron portion 30b and a rectangular portion 30a except for the small projection portion 30c from the first slit 30. And a second slit 31 having a single rectangular shape are formed at intervals of 90 degrees on the circumference.

The operation of the above electromagnetic relief valve will be described.

Solenoid of solenoid control valve from external controller not shown
When the control signal current i corresponding to the desired oil pressure in the pressure oil supply oil passage to the hydraulic actuator is not supplied to the spool 28, the spool 12
Is in contact with the stopper portion 13 by the preload spring F0 to the left of the compression coil spring 26, and at this time, the first slit 3
Neither 0, 30 nor the second slits 31, 31 have a portion overlapping the annular groove 17 of the valve sleeve 10, the annular groove 17 is closed by the spool 12, and the inflow passage 16 of the housing H is screwed by the spool 12 with a large diameter screw. It is cut off from the hole 2, that is, the drain line.

When the control signal current i is supplied and the solenoid 28 is excited, the second member 1b of the valve body 1, which is a magnetic body, is correspondingly excited.
Magnetic lines of force passing through the spool 12, the end surface of the spool 12, the step portion 14, the fourth member 1d and the solenoid cover 29 are formed, and the magnitude of the control signal current i is set between the step portion 14 of the hollow hole and the end surface of the spool 12. The corresponding suction force Fm works. That is, the spool 12 is at a position where the leftward spring force F0 of the compression coil spring 26 and the rightward attraction force Fm corresponding to the magnitude of the control signal current i are balanced. Depending on its position, the first slits 30, 30 and the second slits 31, 31 partially overlap the annular groove 17 of the valve sleeve 10, and the lap region of the slits 30, 30 and the second slits 31, 31 is an orifice. Function as. The control signal current i, that is, the attraction force Fm is increased, and the spool 12 compresses the compression coil spring 26, the opening degrees of the first slits 30, 30 and the second slits 31, 31 are increased, and the right end of the spool 12 is eventually changed. The first slits 30, 30 and the second slits 31, 31 are in a fully opened state in a state of being in contact with the step portion 14. That is, the first slits 30, 30 and the second slits 31, 31 function as variable orifices from the closed state to the fully opened state according to the control signal current i.

A part of the pressure oil from the pressure oil supply source to the hydraulic operating device flows out into the drain pipe according to the opening degree of the variable orifice, so that the hydraulic pressure of the hydraulic oil supplied to the hydraulic operating device is controlled.

Therefore, in the process of the first slit 30 and the second slit 31 changing from the closed state to the open state, first, the small protrusion-shaped portion 30c of the first slit 30 starts to open. Then the first slit 30
Both the chevron portion 30b and the second slit 31 start to open at the same time and open.

A sufficient opening area can be obtained by fully opening the first slit 30 and the second slit 31.

In the opening process of the first slit 30 and the second slit 31, the relationship between the magnitude of the flow force acting by the opening of each slit and the opening stroke of the spool 12 is as shown by the broken line in FIG. Is.

It is as shown by the solid line in which the flow forces acting by the openings of the first slit and the second slit that start in the front and rear are superimposed, and the opening of the slit is from the minute area of the first slit 30 at the beginning. Since the opening area of the second slit 31 is added in the process of starting and increasing, the flow area acting on the spool 12 does not become excessively large because it does not suddenly increase to a large area.
The flow force superposed on the slit and the flow force, which works well on the opening, becomes flat with respect to the change in the opening stroke.

[Effect of device]

In the electromagnetic control valve according to the present invention, when the solenoid is not excited, the spool has the slit at the axial position with the opening degree of zero, the communication between the pressure oil inlet and the pressure oil outlet is cut off, and the solenoid is closed. Is excited by a control current, the spool is displaced in the axial direction by the magnetic force corresponding to the control current, and the opening of the slit starts from a small area of the first slit at the beginning, and in the process of increasing it, the slit opening of the second slit increases. The opening area is added. Therefore, the opening area of the slit is
The flow force that acts on the spool does not suddenly increase from zero to zero, and the flow force that acts on the spool becomes flat with respect to changes in the opening stroke of the slit, so the spool does not vibrate and the valve action is smooth. Therefore, proper control becomes possible. Moreover, when the control current is applied, the opening area of the slit can be increased by the large width portions of the first slit and the second slit, and a sufficient flow rate can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional front view of an electromagnetic control valve according to an embodiment of the present invention, FIG. 2 is a development view of an end peripheral wall of a spool of the electromagnetic control valve according to an embodiment of the present invention, and FIG. FIG. 4 is a development view of the end peripheral wall of the spool of the electromagnetic control valve in FIG. 4, and FIG. 4 shows the opening stroke of the spool and the flow force acting on the spool comparing the electromagnetic control valve in the embodiment of the present invention with the conventional electromagnetic control valve. It is a graph which shows the relationship of. 1: valve body, 1a: first member, 1b: second member, 1c: third member, 1
d: fourth member, 2: large diameter screw hole, 3: inner flange, 4: large diameter hole, 5: medium diameter hole, 6: small diameter screw hole, 7: small diameter hole, 8, 22: through hole,
9: Union, 10: Valve sleeve, 11: Sliding hole, 12: Spool, 13: Stopper part, 14: Step part, 15, 17: Annular groove, 16, 18: Inflow passage, 19: Hollow hole part, 20: Stepped hole, 21: central hole, 23:
Lid plug, 23a, 23b: Threaded part, 24: Sleeve, 25: Nut, 26:
Compression coil spring, 27: O-ring, 28: Solenoid, 29: Solenoid cover, 30a: Rectangular part, 30b: Angled part, 30c: Projected part, 30: First slit, 31: Second slit, H: Housing

Claims (1)

[Scope of utility model registration request] 1. A valve body having a sliding hole formed therein and having a pressure oil inlet opening and a pressure oil outlet opening to the sliding hole, a spool slidably fitted in the sliding hole, and a sliding hole of the spool. The spool is composed of electromagnetic means for controlling the axial displacement due to the magnetic force, and the spool has a first slit in the axial direction having a lateral width of at least a minute width portion and a large portion and a large portion obtained by removing the minute width portion from the first slit. A second axial slit having a lateral width is formed, and the slit is interposed in a communication path between the pressure oil inlet and the pressure oil outlet, and the pressure oil inlet depends on a displacement position of the spool in the axial direction. The opening degree from 0 to full opening is given to the communication between the pressure oil outlet and the pressure oil outlet, and at the start of opening, the spool is formed in a position direction in which it opens from only a minute width portion. Control valve