JP2002147642A - Solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid valve capable of realizing the increase of the maximum capacity without enlarging a device. SOLUTION: In this solenoid valve comprising a sleeve 1 having a valve hole 15, a shaft 3 axially displaceably supported to the sleeve 1 through bearings 4, 5, a first spring 11 for energizing the shaft 3 in the valve closing direction, and a plunger 7 for driving the shaft 3 against the first spring by solenoid thrust Fsol of a coil 9, and a poppet 2 defining a variable restriction part 8 with the valve hole 15 is formed a body separated from the shaft 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a solenoid valve.

[0002]

2. Description of the Related Art Conventionally, as this type of solenoid valve, for example, there is one shown in FIG.

To explain this, the electromagnetic proportional flow control valve includes a cylindrical sleeve 1 inserted and attached to a pump body 10 and a shaft 3 slidably inserted into the sleeve 1. The sleeve 1 has an upstream chamber 14 communicating with the discharge side of the pump, a valve hole 15 defining the variable throttle portion 8 between the shaft 3, and a downstream chamber 16 communicating with the load side. The working fluid discharged from the pump flows to the load through the upstream chamber 14, the valve hole 15, and the downstream chamber 16, as indicated by the outline arrows in the drawing.

[0004] The cylindrical shaft 3 is slidably interposed between the sleeve 1 and the base 6 via a pair of bearings 4 and 5. The shaft 3 has a conical shaft end face 2 at its tip.
5 is formed, and the shaft end face 25 is inserted into the valve hole 15. As the shaft 3 is displaced rightward in the figure, the opening area Av of the variable throttle 8 defined between the shaft end face 25 and the valve hole 15 gradually increases.

[0005] A spring 11 for urging the shaft 3 in a valve closing direction (left direction in the figure) is provided. The spring 11 is compressed and interposed between the end face of the shaft 3 and the adjuster 13. By changing the screwing position of the adjuster 13 with respect to the base 6, the spring force of the spring 11 is changed, and the absolute value of the flow rate is adjusted as described later.

A plunger (movable iron core) 7 is fixed in the middle of the shaft 3, and an electromagnetic coil 9 for driving the plunger 7 is provided outside the base 6. The plunger 7 drives the shaft 3 in a valve opening direction (rightward in the figure) by a solenoid thrust Fsol generated in the coil 9.

The electromagnetic proportional flow control valve is constructed as described above, and the following four forces are applied to the shaft end face 25. Fsol: Solenoid thrust of the coil 9 acting on the plunger 7 Fk: Spring force of the spring 11 FΔP: Force due to the differential pressure ΔP of the variable throttle unit 8 Ff: Fluid force generated in the variable throttle unit 8 Here, the shaft end face 25 is opened. Assuming that the force acting in the direction (rightward in the figure) is a positive value, the following equation holds. Fsol−Fk + FΔP−Ff = 0 (1) When this is arranged for Fsol, Fsol = Fk−FΔP + Ff (2) The shaft end face 25 is moved to a position where the above equation is satisfied, and the variable throttle unit 8 obtained by this is obtained. A control flow Qc proportional to the opening area Av and the differential pressure ΔP across the variable throttle unit 8 flows.

[0008]

However, in such a conventional electromagnetic proportional flow control valve, the dimensions such as the length and diameter of the coil 9 are optimally adjusted so as not to be excessive or insufficient according to the maximum control flow rate Qcmax. When it is necessary to control a large flow rate exceeding the initially planned maximum control flow rate Qcmax, the diameter of the valve hole 15 and the shaft end face 25 is increased to increase the opening area Av of the variable throttle unit 8. Thus, it was necessary to increase the flow rate. As a result, there has been a problem that the dimensions in the radial direction are increased in each part including the bearings 4 and 5, and the electromagnetic proportional flow control valve is increased in size.

When the pressure receiving area Am of the shaft end face 25 is increased, it is necessary to increase the Fk of the equation (2) with the increase of FΔP of the equation (2). However, when the spring force Fk of the spring 11 is increased in a limited space, the strength of the spring 11 is reduced. In order to avoid this, the space for interposing the spring 11 becomes large,
There is a problem that the electromagnetic proportional flow control valve becomes large.

The present invention has been made in view of the above problems, and has as its object to provide an electromagnetic valve capable of increasing the maximum flow rate without increasing the size of the device.

[0011]

According to a first aspect of the present invention, there is provided a valve hole communicating between a pressure source side and a load side, a shaft supported to be axially displaceable with respect to the valve hole, A spring for biasing, and a coil for driving the shaft against the spring by a solenoid thrust,
The present invention is applied to a solenoid valve in which an opening area of a variable throttle portion defined in a valve hole is variable according to displacement of a shaft.

A poppet defining a variable throttle between the valve hole and the valve hole is formed separately from the shaft.

According to a second aspect, in the first aspect, a plurality of springs for urging the shaft in the axial direction are provided in parallel.

According to a third aspect of the present invention, in the second aspect, a plunger in which a solenoid thrust of a coil works is fitted to an outer periphery of a shaft, and a counterbore portion is formed on an inner periphery of the plunger to interpose a spring. It was assumed that.

[0015]

According to the first invention, the outside diameter of the poppet and the opening diameter of the valve hole are set large according to the required maximum control flow rate, and the opening area of the variable throttle section is enlarged. Since the poppet is formed separately from the shaft, even if the outer diameter of the poppet is increased, it is not necessary to increase the radial dimension of each part including the shaft and its bearings. can avoid.

According to the second aspect, the spring force of each spring can be reduced and the strength of each spring can be increased as compared with the conventional structure in which a single spring is provided.

According to the third aspect of the present invention, the counterbore portion is formed on the inner periphery of the plunger, and the spring is arranged along the outer periphery of the shaft. .

[0018]

FIG. 1 is a block diagram showing an embodiment of the present invention.
It will be described based on. The same components as those of the conventional example shown in FIG. 2 are denoted by the same reference numerals.

The electromagnetic proportional flow control valve basically comprises a sleeve 1 having a valve hole 15 opened,
A shaft 3 supported so as to be axially displaceable with respect to the sleeve 1 via bearings 4 and 5; and a plunger 7 for driving the shaft 3 by a solenoid thrust Fsol of a coil 9.
And

The poppet 2 defining the variable throttle portion 8 with the valve hole 15 is formed separately from the shaft 3. The poppet 2 is formed in a bottomed cylindrical shape that is press-fitted and attached to the tip of the shaft 3, and has a poppet end face 21 that protrudes conically into the valve hole 15 at the tip.

A valve wall 17 having a valve hole 15 formed therein is formed in the sleeve 1 for accommodating the shaft 3 and the poppet 2 at right angles to the axial direction of the shaft 3. Therefore, as the conical poppet end face 21 is displaced rightward in the drawing, the opening area Av of the variable throttle 8 gradually increases. The opening diameter of the valve hole 15 is formed larger than the outer diameter of the poppet 2.

The shaft 3 is connected to the opening area Av of the variable throttle 8.
The first spring 11 and the second spring 12 that urge in the valve-closing direction (left direction in the figure) in which is smaller are provided in parallel.

The first spring 11 is compressed and interposed between the end face of the shaft 3 and the adjuster 13. By changing the screwing position of the adjuster 13 with respect to the base 6,
The spring force of the first spring 11 changes, and the magnitude of the absolute value of the flow rate is adjusted.

The second spring 12 is interposed between the plunger 7 and the bearing 5. A counterbore 19 is formed on the inner periphery of the plunger 7, and the second spring 12 is accommodated between the counterbore 19 and the shaft 3. The depth of the counterbore 19 is determined according to the length of the second spring 12.

The electromagnetic proportional flow control valve is configured as described above, and the operation will be described next.

There are the following four forces acting on the poppet 2. Fsol: Solenoid thrust of the coil 9 acting on the plunger 7 Fk1: Spring force of the first spring 11 Fk2: Spring force of the second spring 12 FΔP: Force due to the differential pressure ΔP before and after the variable throttle unit 8 Ff: Generated in the variable throttle unit 8 Here, assuming that the force acting in the valve opening direction of the poppet 2 (rightward in the figure) is a positive value, the following equation is established. Fsol = Fk1 + Fk2−FΔP + Ff (3) The poppet 2 moves to a position where the above equation is satisfied, and the control flow rate proportional to the opening area Av of the variable throttle unit 8 and the differential pressure ΔP across the variable throttle unit 8 obtained by this. Qc flows.

Therefore, the required maximum control flow rate Qc
The outside diameter of the poppet 2 and the opening diameter of the valve hole 15 may be set to be large in accordance with max, so that the opening area Av of the variable diaphragm 8 may be increased. Since the poppet 2 is formed separately from the shaft 3, even if the outer diameter of the poppet 2 is increased,
There is no need to increase the outer diameter of the shaft 3, and the bearings 4, 5
The size of the electromagnetic proportional flow control valve, in which the radial dimension increases in each part including the above, can be avoided from being increased.

The first spring 11 and the second spring 12 for urging the shaft 3 in the valve closing direction are provided in parallel with each other, so that the first spring 11 and the second spring 12 have respective spring forces Fk1 and Fk1, compared to a conventional structure in which a single spring is provided. Fk2 is halved, and the strength of each is increased.

Since the counterbore 19 is formed on the inner periphery of the plunger 7 and the second spring 12 is arranged along the outer periphery of the shaft 3, the space between the second spring 12 allows the electromagnetic proportional flow control valve to be mounted. Larger size can be avoided.

It is apparent that the present invention is not limited to the above-described embodiment, and that various changes can be made within the scope of the technical idea.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electromagnetic proportional flow control valve showing an embodiment of the present invention.

FIG. 2 is a sectional view of an electromagnetic proportional flow control valve showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sleeve 2 Poppet 3 Shaft 4,5 Bearing 6 Base 7 Plunger 8 Variable throttle part 9 Coil 11 First spring 12 Second spring 19 Counterbore part

Continuation of the front page F term (reference) 3H106 DA05 DA23 DB02 DB22 DB32 DC02 DC17 DD03 EE34 GA23 GB06

Claims (3)

[Claims] A valve hole communicating between the pressure source side and the load side; a shaft supported to be axially displaceable with respect to the valve hole; a spring for urging the shaft in the axial direction; And a coil that drives the shaft against the spring by means of a solenoid valve that varies the opening area of a variable throttle section defined in the valve hole with the displacement of the shaft. An electromagnetic valve, wherein a poppet defining the variable throttle portion is formed separately from the shaft. 2. The solenoid valve according to claim 1, wherein a plurality of springs for urging the shaft in the axial direction are provided in parallel. 3. A plunger in which a solenoid thrust of the coil acts on an outer periphery of the shaft, and a counterbore for interposing the spring is formed on an inner periphery of the plunger. The described solenoid valve.