JP3743733B2 - Solenoid proportional control valve - Google Patents

Description

[0001]
BACKGROUND 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 path is controlled by a reciprocating electromagnetic solenoid.
[0002]
[Prior art]
For example, there is an expansion valve used in a refrigeration cycle of a car air conditioner in which the flow rate of the refrigerant sent to the evaporator is controlled by an electromagnetic proportional control valve that drives a valve body with a reciprocating electromagnetic solenoid.
[0003]
In general, such an electromagnetic proportional control valve has a valve body disposed opposite to an opening of a throttle hole formed by narrowing a cross-sectional area in the middle of a flow path through which a refrigerant passes, and the refrigerant pressure is applied to the valve body. On the other hand, various structures are employed in order not to act in the opening / closing direction.
[0004]
[Problems to be solved by the invention]
However, in order to prevent fluid pressure from acting on the valve body in the opening / closing direction, generally, a communicating hole is formed in the valve body in the axial direction so that the refrigerant of the same pressure faces both the front and back surfaces of the valve body. As a result, the structure of the valve body and the flow path surrounding it has become complicated, and the shape of the parts is difficult to process, resulting in high manufacturing costs.
[0005]
Accordingly, an object of the present invention is to provide an electromagnetic proportional control valve that has a simple structure for preventing fluid pressure from acting on the valve body in the opening / closing direction and is easy to manufacture.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an electromagnetic proportional control valve according to the present invention is provided between 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. A guide rod disposed through the throttle hole with a gap in between, and a valve body that is fitted to the throttle hole so as to be capable of moving forward and backward in the axial direction and is opposed to the opening of the throttle hole. And an urging spring and a reciprocating electromagnetic solenoid for urging the valve body in directions opposite to each other in the axial direction of the guide rod, at a position on the back side when viewed from the side facing the throttle hole of the valve body The diameter of the fitting portion between the valve body and the guide rod is formed to be the same as the diameter of the throttle hole.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
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 cold amount fed into an evaporator (not shown) while being adiabatically expanded during a refrigeration cycle of a car air conditioner. However, the present invention can be applied not only to an expansion valve but also to an electromagnetic proportional control valve for controlling the flow rate of various fluids.
[0008]
Reference numeral 1 denotes a main body block of an expansion valve, which is formed with a refrigerant flow path 2 through which a refrigerant to be fed into the evaporator is passed. 2a is a high-pressure refrigerant inlet through which high-pressure refrigerant sent from a liquid tank (not shown) enters, and 2b is a refrigerant outlet through which the refrigerant is sent to the evaporator while adiabatically expanding.
[0009]
The refrigerant channel 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 channel 2 is squeezed halfway. A valve body 6 having a conical shape on the surface thereof 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.
[0010]
A guide rod 5 having an outer diameter dimension that allows a gap for the refrigerant to flow between the inner peripheral surface of the throttle hole 3 and the outer diameter thereof is inserted through the throttle hole 3. One end side is press-fitted and fixed to the main body block 1 on the downstream side.
[0011]
A hole 6a through which the guide rod 5 is loosely inserted is formed in the valve body 6 so as to penetrate the axial position, and the valve body 6 is fitted to the guide rod 5 so as to be able to advance and retract. Yes.
[0012]
A reciprocating electromagnetic solenoid 10 is screwed and fixed to the main body block 1 at a position behind the valve body 6 when viewed from the valve seat 7. 11 is an electromagnetic coil, 12 is a fixed iron core.
[0013]
The movable iron core 13 of the electromagnetic solenoid 10 is disposed between the fixed iron core 12 and the valve body 6 in a state in which the movable iron core 13 is fitted into the sleeve 14 so as to be freely advanced and retracted. Further, a compression coil spring 15 is mounted in a compressed state between the fixed iron core 12 and the movable iron core 13.
[0014]
The guide rod 5, the throttle hole 3, the valve seat 7, the valve body 6, the sleeve 14, the movable iron core 13 and the like are arranged on the same central axis. Reference numerals 9 and 19 denote sealing O-rings.
[0015]
On 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 (that is, the back surface as viewed from the valve seat 7 side) is fixed by caulking. Therefore, when the movable iron core 13 moves, the valve body 6 moves with it.
[0016]
The portion 5a in the vicinity of the end of the guide rod 5 on the non-fixed side is formed so that the outer diameter is substantially the same as the inner diameter of the throttle hole 3, and the portion closer to the back side of the valve body 6 is the larger diameter. The end portion 5a is loosely fitted. As a result, the diameter of the fitting portion between the large diameter end portion 5 a of the guide rod 5 and the valve body 6 is the same as the diameter of the throttle hole 3.
[0017]
FIG. 1 shows a state in which the valve body 6 is in an intermediate position between the fully closed state and the fully open state. In this state, the non-fixed side (large diameter end portion 5a) of the guide rod 5 is shown. The end face and the rear face of the valve body 6 are located on the same plane.
[0018]
8 is a thin rubber elastic sheet that seals between the end surface of the large-diameter end portion 5a of the guide rod 5 and the end portion of the movable iron core 13 connected thereto, and the end surface of the movable iron core 13 and the valve element 6 is sandwiched between the back surface of 6. One end of the fixed rod 16 that is loosely inserted in 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.
[0019]
Therefore, the fixed rod 16, the elastic sheet 8, and the guide rod 5 are fixedly disposed between the fixed iron core 12 and the main body block 1, and the movable iron core 13 and the valve fixed thereto. The body 6 can freely slide in the axial direction with respect to the fixed rod 16 and the guide rod 5. Accordingly, the elastic sheet 8 is elastically deformed.
[0020]
FIG. 2 shows the state of the refrigerant pressure acting on the valve body 6. The effective pressure receiving area where the valve body 6 receives the refrigerant pressure slightly reduced 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 back surface side. (Refrigerant pressure is transmitted to the back side through a gap in the fitting portion between the guide rod 5 and the valve body 6).
[0021]
Here, as described above, the diameter of the fitting portion between the large-diameter end portion 5 a of the guide rod 5 and the valve body 6 is the same as the diameter of the throttle hole 3. The effective pressure receiving area S1 on the front surface side that receives the refrigerant pressure that is slightly reduced is equal to the effective pressure receiving area S2 on the back surface side (that is, S1 = S2).
[0022]
And in the part of the outer side of the valve body 6, the pressure of the high pressure refrigerant | coolant before reaching the throttle hole 3 acts on the valve body 6 equally from the front and back both sides. Therefore, no refrigerant pressure (differential pressure) acts on the valve body 6 in the opening / closing direction.
[0023]
In the expansion valve configured as described above, when the electromagnetic coil 11 of the electromagnetic solenoid 10 is not energized, the movable iron core 13 urges the valve body 6 in the opening / closing direction as shown in FIG. Therefore, 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.
[0024]
When 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 acts in the direction of compressing and compressing the compression coil spring 15.
[0025]
As a result, the valve body 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. 4 shows a state in which the valve body 6 is fully opened.
[0026]
FIG. 5 shows the overall structure of the above-described expansion valve. A low-pressure refrigerant flow path 20 through which a low-pressure refrigerant sent from an evaporator (not shown) passes is formed in the main body block 1, and the low-pressure refrigerant flow path 20 A temperature and pressure sensor 30 is arranged so as to communicate with. Then, the energization current to the electromagnetic solenoid 10 is controlled corresponding to the output signal from the temperature / pressure sensor 30.
[0027]
The present invention is not limited to the above-described embodiment. For example, the large-diameter end portion 5a may be formed by fixing a pipe material or the like to the guide rod 5, and the fixed rod 16 is omitted. May be.
[0029]
【The invention's effect】
According to the present invention, the diameter of the fitting portion of 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 diameter as the diameter of the throttle hole. Since the effective pressure receiving area on the front side that receives the pressure of the fluid in the throttle hole is equal to the effective pressure receiving area on the back side, the fluid pressure does not act on the valve body in the opening and closing direction with a very simple structure. Therefore, 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 fluid pressure applied to the 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 an overall 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 part 6 Valve body 10 Electromagnetic solenoid 13 Movable iron core 15 Compression coil spring

Claims (1)

A throttle hole formed by narrowing the cross-sectional area in the middle of the flow path through which the fluid passes;
A guide rod fixedly arranged in a state of passing through the throttle hole with a gap between the inner peripheral surface of the throttle hole;
A valve body that is fitted to the guide rod so as to be movable back and forth in the axial direction and is disposed at a position facing the opening of the throttle hole;
The valve body is provided a reciprocating electromagnetic solenoid and biasing spring for each biased in opposite directions in the axial direction of the guide rod,
The diameter of the fitting portion between the valve body and the guide rod at a position on the back side as viewed from the side facing the throttle hole of the valve body is formed to the same diameter as the diameter of the throttle hole ,
The back side surface of the valve body is fixed to the one end side surface of the movable core of the electromagnetic solenoid formed in a cylindrical shape, and the surface between the one end side of the movable core and the back side surface of the valve body Placed in a state of sandwiching an elastic elastic sheet that seals between them,
Between the one end surface of the fixed rod that is loosely inserted in the movable iron core and the one end surface of the guide rod, sandwich the portion near the center of the elastic sheet,
The electromagnetic proportional control characterized in that the elastic sheet is elastically deformed as the movable iron core and the valve body slide in the axial direction with respect to the fixed rod and the guide rod. valve.

Images