JPH10299934A - Solenoid proportional control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid proportional control valve with a simple structure to prevent the fluid pressure from acting to the open-close direction against a valve element and easily manufactured. SOLUTION: A restriction hole 3 formed by tapering the cross-sectional area at the halfway of a passage 2 flowing the fluid, a guide rod 5 arranged by forming a gap between the restriction hole 3 and its inner periphery so as to penetrate the restriction hole 3, a valve element 6 inserted movable to an axis direction against the restriction hole 3 and arranged at the position facing to the opening of the restriction hole 3, an exciting spring 15 exciting the valve element 6 respectively to the opposite direction of the axis direction of the guide rod 5, a reciprocating solenoid 10 are provided. The diameter of the fitted part between the valve element 6 and the guide rod 5 at the backside position as seen from the side facing to the restriction hole 3 of the valve 6 is formed as the same diameter as of the restriction hole 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic proportional control valve in which a flow rate of a fluid passing through a flow passage is controlled by a reciprocating electromagnetic solenoid.

[0002]

2. Description of the Related Art For example, an expansion valve used in a refrigeration cycle of a car air conditioner has a valve in which a flow rate of a refrigerant sent to an evaporator is controlled by an electromagnetic proportional control valve in which a valve element is driven by a reciprocating electromagnetic solenoid. is there.

In such an electromagnetic proportional control valve, generally, a valve element is disposed so as to face an opening of a throttle hole formed by narrowing a cross-sectional area in the middle of a flow path through which a refrigerant flows, and the refrigerant pressure is reduced. Various structures are adopted to prevent the valve body from acting in the opening and closing directions.

[0004]

However, in order to prevent the fluid pressure from acting on the valve body in the opening and closing directions, a communication hole is generally formed in the valve body in the axial direction so that the front and back of the valve body are formed. Since the refrigerant at the same pressure faces both sides, the structure of the valve body and the flow path surrounding the valve body becomes complicated, and the shape of parts becomes difficult to process, and the manufacturing cost is high.

Accordingly, an object of the present invention is to provide an electromagnetic proportional control valve which has a simple structure for preventing fluid pressure from acting on the valve body in the opening and closing directions and is easy to manufacture.

[0006]

In order to achieve the above object, an electromagnetic proportional control valve according to the present invention comprises: a throttle hole formed by narrowing a cross-sectional area in the middle of a flow path through which a fluid passes; A guide rod disposed through the throttle hole with a gap between the inner peripheral surface of the throttle hole and a guide rod that is fitted to the throttle hole so as to be able to advance and retreat in the axial direction with respect to the throttle hole, and is fitted to the opening of the throttle hole. A valve element disposed at an opposing position, an urging spring and a reciprocating electromagnetic solenoid for urging the valve element in directions opposite to each other in the axial direction of the guide rod are provided, and in the throttle hole of the valve element. The diameter of the fitting portion between the valve body and the guide rod at the position on the back side when viewed from the facing side is formed to be the same as the diameter of the throttle hole.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an expansion valve used for controlling a flow rate of a cooling amount sent while adiabatically expanding an evaporator (not shown) in a refrigeration cycle of a car air conditioner. However, the present invention is not limited to the expansion valve, and can be applied to an electromagnetic proportional control valve for controlling the flow rates of various fluids.

Reference numeral 1 denotes a main body block of the expansion valve, in which a refrigerant passage 2 through which a refrigerant to be sent to the evaporator is formed is formed. 2a is a high-pressure refrigerant inlet through which a high-pressure refrigerant sent from a liquid tank (not shown) enters;
Is a refrigerant outlet from which the refrigerant is sent to the evaporator while being adiabatically expanded.

The refrigerant passage 2 is formed in a substantially crank shape with an intermediate portion bent at a right angle, and the portion is a throttle hole 3 in which the cross-sectional area of the refrigerant passage 2 is reduced in the middle. A valve body 6 having a conical surface is disposed facing the opening of the throttle hole 3 from the upstream side, and the opening of the throttle hole 3 facing the valve body 6 is a valve. It is seat 7.

In the throttle hole 3, a guide rod 5 having an outer diameter dimension enough to secure a gap through which the refrigerant flows between the throttle hole 3 and the inner peripheral surface of the throttle hole 3 is inserted therethrough. One end of the guide rod 5 is press-fitted and fixed to the main body block 1 on the downstream side.

A hole 6a through which the guide rod 5 is loosely inserted penetrates the valve body 6 at an axial position.
Are fitted to the guide rod 5 so as to be able to move forward and backward.

A reciprocating electromagnetic solenoid 10 is screwed and fixed to the main body block 1 at a position rearward of the valve body 6 as viewed from the valve seat 7. 11 is an electromagnetic coil,
Reference numeral 12 denotes a fixed iron core.

The movable iron core 13 of the electromagnetic solenoid 10 is fitted into the sleeve 14 so as to be movable forward and backward, and the fixed iron core 1
2 and the valve body 6. In addition, fixed iron core 1
2 and the movable iron core 13, a compression coil spring 1
5 is mounted in a compressed state.

The guide rod 5, the throttle hole 3, the valve seat 7,
The valve 6, the sleeve 14, the movable iron core 13, and the like are arranged on the same central axis. 9 and 19 are O-rings for sealing.

At the end of the movable iron core 13 opposite to the side facing the fixed iron core 12, the back surface portion of the valve body 6 (ie, the surface on the back side when viewed from the valve seat 7 side) is fixed by caulking. I have. Therefore, when the movable iron core 13 moves, the valve body 6 moves together therewith.

The portion 5a near the end of the guide rod 5 on the non-fixed side is formed so as to have an outer diameter that is substantially the same as the inner diameter of the throttle hole 3 and is thicker. It is in a state of being loosely fitted to the large-diameter end portion 5a. As a result, the diameter of the fitting portion between the large diameter end portion 5a of the guide rod 5 and the valve body 6 is the same as the diameter of the throttle hole 3.

FIG. 1 shows a state in which the valve body 6 is at an intermediate position between the fully closed state and the fully opened state. In this state, the non-fixed side (the large diameter end) of the guide rod 5 is shown. The end surface of the portion 5a) and the back surface of the valve element 6 are located on the same plane.

Reference numeral 8 denotes a thin rubber elastic sheet for sealing between the end face of the large diameter end 5a of the guide rod 5 and the end of the movable iron core 13 connected thereto. And the back surface of the valve body 6. One end of the fixed rod 16 loosely inserted into the movable iron core 13 is in contact with the fixed iron core 12, and the other end is in contact with the back surface of the elastic sheet 8.

Therefore, the fixed rod 16, the elastic sheet 8 and the guide rod 5 are fixed to the fixed iron core 12 and the main body block 1.
And the movable iron core 13 and the valve element 6 fixed thereto are fixed to each other by a fixed rod 16.
And the guide rod 5 can be freely slid in the axial direction. Then, the elastic sheet 8 elastically deforms accordingly.

FIG. 2 shows the state of the refrigerant pressure acting on the valve element 6. The effective pressure receiving area in which the valve element 6 receives the slightly reduced refrigerant pressure in the throttle hole 3 is the cross-sectional area S1 of the throttle hole 3 on the front surface side, and the fitting portion with the large-diameter end portion 5a on the rear surface side. (The refrigerant pressure is transmitted to the back side through the gap between the fitting portions of the guide rod 5 and the valve body 6).

As described above, since the diameter of the fitting portion between the large-diameter end portion 5a of the guide rod 5 and the valve body 6 is equal to the diameter of the throttle hole 3, the valve body 6 is restricted. The effective pressure receiving area S1 on the front surface side receiving the slightly reduced refrigerant pressure in the hole 3 is equal to the effective pressure receiving area S2 on the rear surface side (that is, S1 = S2).

At the outer portion of the valve element 6, the pressure of the high-pressure refrigerant before reaching the throttle hole 3 acts on the valve element 6 evenly from both front and back sides. Therefore, the refrigerant pressure (differential pressure) does not act on the valve body 6 in the opening / closing direction at all.

In the expansion valve configured as described above,
In a state in which the electromagnetic coil 11 of the electromagnetic solenoid 10 is not energized, as shown in FIG.
Since the valve body 3 does not urge the valve body 6 in the opening / closing direction at all, the valve body 6 is pressed against the valve seat 7 by the urging force of the compression coil spring 15, and the flow rate of the refrigerant flowing in the refrigerant flow path 2 becomes zero.

As the current flowing through the electromagnetic coil 11 is increased, as shown in FIG. 1, the thrust (biasing force) of the movable iron core 13 generated by the electromagnetic force is applied to the compression coil spring 15.
Acts in the direction of compressing.

As a result, the valve element 6 stops at a position where the thrust of the movable iron core 13 and the urging force of the compression coil spring 15 are balanced, and the flow rate control proportional to the current value is performed. FIG.
Shows a state where the valve body 6 is fully opened.

FIG. 5 shows the entire structure of the above-mentioned expansion valve. A low-pressure refrigerant flow path 20 through which a low-pressure refrigerant sent from an evaporator (not shown) is formed is formed in the main body block 1. A temperature / pressure sensor 30 is arranged so as to communicate with the flow path 20. The electromagnetic solenoid 1 responds to the output signal from the temperature / pressure sensor 30.
The current flowing to zero is controlled.

The present invention is not limited to the above embodiment. For example, the large diameter end 5a is
The fixing rod 16 may be omitted by fixing a pipe material or the like.

Further, the large-diameter end portion 5a of the guide rod 5 is formed so as to extend straight into the movable iron core 13, and the elastic sheet 8 is formed.
In place of the above, an annular seal member is provided with the movable iron core 13 and the large diameter end 5.
It may be configured to be mounted on the fitting portion with the a.

[0029]

According to the present invention, the diameter of the fitting portion between the valve body and the guide rod at the position on the back side when viewed from the side facing the throttle hole of the valve body is formed to be the same as the diameter of the throttle hole. As a result, the effective pressure receiving area on the front surface side and the effective pressure receiving area on the rear surface side of the valve element receiving the pressure of the fluid in the throttle hole become equal,
With a very simple structure, the fluid pressure can be prevented from acting on the valve body in the opening and closing directions, and an electromagnetic proportional control valve that operates accurately can be easily manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electromagnetic proportional control valve according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a state of a fluid pressure applied to a valve body according to the embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of the electromagnetic proportional control valve according to the embodiment of the present invention in a fully closed state.

FIG. 4 is a longitudinal sectional view of the electromagnetic proportional control valve according to the embodiment of the present invention in a fully opened state.

FIG. 5 is a longitudinal sectional view showing the entire configuration of an embodiment in which the present invention is applied to an expansion valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body block 2 Refrigerant flow path 3 Restriction hole 5 Guide rod 5a Large diameter end 6 Valve body 10 Electromagnetic solenoid 13 Moving iron core 15 Compression coil spring

Claims (1)

[Claims] 1. A throttle hole formed by narrowing a cross-sectional area in the middle of a flow path through which a fluid passes, and an inner peripheral surface of the throttle hole with a gap therebetween to penetrate the throttle hole. An arranged guide rod, a valve body fitted to the throttle hole so as to be able to advance and retreat in the axial direction and arranged at a position opposed to an opening of the throttle hole, and a valve body arranged in the axial direction of the guide rod. A biasing spring and a reciprocating electromagnetic solenoid are provided, each of which biases in a direction opposite to each other, and a fitting portion between the valve body and the guide rod at a position on the back side when viewed from the side facing the throttle hole of the valve body. Characterized in that the diameter of the throttle valve is formed to be the same as the diameter of the throttle hole.