JP7565128B1 - Solenoid valve - Google Patents

Abstract

[Problem] To provide a small solenoid valve that can be opened and closed even under high differential pressure. [Solution] The solenoid valve 1 comprises a valve body 10 having an inlet passage 12 communicating with a main valve chamber 11, a main valve seat 14 arranged in the main valve chamber 11, and an outlet passage 13, a main valve element 20 having a pilot valve port 25 and capable of opening and closing the outlet passage 13 by being seated on or separated from the main valve seat 14, a pilot valve element 30 capable of opening and closing the pilot valve port 25, and a drive unit 40 capable of driving the pilot valve element 30. The drive unit 40 has an electromagnetic coil 41, a plunger 42 movable in the central axis direction Y of the electromagnetic coil 41, an attractor 44 fixed to the valve body 10 and capable of attracting the plunger 42 by the electromagnetic force of the electromagnetic coil 41, and a first coil spring 46a and a second coil spring 46b that bias the pilot valve element 30 in a direction away from the pilot valve port 25. [Selected Figure] FIG.

Description

This disclosure relates to a solenoid valve.

There is a known type of solenoid valve that closes when energized; when the electromagnetic coil is energized, the attractive force between the plunger and the attractor pushes the pilot valve body down toward the pilot valve port to close the valve, and when the electromagnetic coil is de-energized, the coil spring pushes the pilot valve body up from the pilot valve port to open the valve (see, for example, Patent Document 1).

JP 2022-112146 A

To enable the valve to open even when the pressure difference between the pilot inlet and outlet passages is high, the elastic force of the coil spring must be increased. However, if the elastic force of the coil spring is increased, the suction force between the plunger and the attractor to close the valve must also be increased, which creates the problem of the solenoid valve becoming larger.

The objective of this disclosure is to provide a compact solenoid valve that can be opened and closed even under high differential pressure.

A solenoid valve according to one aspect of the present invention comprises:
a valve body including an inlet passage communicating with a main valve chamber, a main valve seat disposed within the main valve chamber, and an outlet passage;
a main valve body that is provided with a pilot valve port and is capable of opening and closing the outflow path by being seated on or separated from the main valve seat;
a pilot valve body capable of opening and closing the pilot valve port;
a drive unit capable of driving the pilot valve body;
Equipped with
The drive unit is
An electromagnetic coil;
A plunger movable along a central axis of the electromagnetic coil;
an attractor fixed to the valve body and capable of attracting the plunger by the electromagnetic force of the electromagnetic coil;
a first coil spring and a second coil spring that bias the pilot valve body in a direction away from the pilot valve port;
having
When a gap between the plunger and the attractor in the central axial direction is equal to or smaller than a predetermined value, the pilot valve body is biased by the first coil spring and the second coil spring,
When the gap is greater than the predetermined value, the pilot valve element is biased by the first coil spring.

This disclosure makes it possible to provide a small solenoid valve that can be opened and closed even under high differential pressure.

FIG. 2 is a vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when not energized. FIG. 2 is a vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when energized; FIG. 2 is a partial vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when not energized. FIG. 2 is a partial vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when energized; 6 is a graph showing the relationship between the gap and the load of the solenoid valve according to the reference example. 4 is a graph showing a relationship between a gap and a load of a solenoid valve according to an embodiment of the present disclosure.

Embodiments of the present invention will be described below with reference to the drawings. For the sake of convenience, descriptions of configurations having the same reference numbers as configurations already described in the description of the embodiments will be omitted. In the description of the embodiments below, the up and down directions refer to the directions within the paper plane of Figures 1 to 4, and are not intended to narrow the technical scope of the present disclosure.

<Internal structure of solenoid valve>
The internal structure of the solenoid valve will be described with reference to Figures 1 and 2. Figure 1 is a vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when not energized. Figure 2 is a vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when energized.

As shown in Figures 1 and 2, the solenoid valve 1 of this embodiment is a pilot-operated solenoid valve that controls a fluid such as a high-pressure refrigerant, and has a valve body 10, a main valve element 20, a pilot valve element 30, and a drive unit 40. The valve body 10, the main valve element 20, the pilot valve element 30, and the drive unit 40 are arranged coaxially in the central axis direction Y.

The valve body 10 is a substantially cylindrical member extending in the central axis direction Y, and has an internal space in which the main valve body 20 is housed. The internal space is divided by the main valve body 20 into a main valve chamber 11 located below the main valve body 20, and a back pressure chamber 21 located above the main valve body 20. The valve body 10 has an inlet passage 12 that communicates with the main valve chamber 11 in the left-right direction, and an outlet passage 13 that extends downward from the main valve chamber 11. A cylindrical main valve seat 14 is formed at the opening of the outlet passage 13, surrounding the outlet passage 13 and protruding toward the main valve chamber 11.

The main valve body 20 has a generally cylindrical shape extending in the central axis direction Y, and is arranged to be movable up and down within the internal space of the valve body 10. The main valve body 20 can open and close the outflow passage 13 by being seated on or separated from the main valve seat 14. Therefore, when the main valve body 20 is in an open state, the fluid that flows in from the inlet passage 12 flows out into the outflow passage 13 via the main valve chamber 11, and when the main valve body 20 is in a closed state, the fluid remains in the main valve chamber 11 without flowing out into the outflow passage 13.

The main valve body 20 has a pilot inlet passage 22 that extends in the vertical direction. A portion of the fluid that flows into the main valve chamber 11 flows into the back pressure chamber 21 via the pilot inlet passage 22. The main valve body 20 also has a pilot outlet passage 23 that extends in the vertical direction. The pilot outlet passage 23 has a pilot valve port 25 on the back pressure chamber 21 side. A pilot valve seat 24 is formed on the upper surface of the main valve body 20 so as to surround the pilot valve port 25.

The pilot valve body 30 has a generally cylindrical shape and can open and close the pilot valve port 25 by seating on or separating from the pilot valve seat 24. The pilot valve body 30 is disposed inside the suction element 44 and is connected to the plunger 42 via the valve shaft 43. When the pilot valve port 25 is in an open state, the fluid in the back pressure chamber 21 flows out to the pilot outlet passage 23, and when the pilot valve port 25 is in a closed state, the fluid in the back pressure chamber 21 remains in the back pressure chamber 21 without flowing out to the pilot outlet passage 23.

The drive unit 40 has an electromagnetic coil 41, a plunger 42, a valve shaft 43, an attractor 44, and a cylindrical support part 49. The plunger 42 is supported by the cylindrical support part 49 inside the electromagnetic coil 41 so as to be movable in the vertical direction. The attractor 44 has a substantially cylindrical shape, is arranged so as to face the plunger 42 in the vertical direction, and is fixed and supported by the cylindrical support part 49 and the valve body 10. The valve shaft 43 has a substantially cylindrical shape extending in the central axis direction Y, and the upper part of the valve shaft 43 is fixed to the plunger 42, and the lower part of the valve shaft 43 is arranged inside the attractor 44 so as to be movable in the vertical direction. The electromagnetic coil 41 is connected to an external power source (not shown), and an electromagnetic force is generated that attracts the plunger 42 and the attractor 44 to each other by passing a drive current through the electromagnetic coil 41. As shown in FIG. 2, the plunger 42 is pulled down toward the attractor 44 by the electromagnetic force, which pushes down the pilot valve body 30 via the valve shaft 43, thereby closing the pilot valve port 25. At this time, if the distance in the central axis direction Y between the plunger 42 and the attractor 44 is defined as the gap G, the gap G becomes smaller.

In the space between the suction element 44 and the pilot valve body 30, a cylindrical first coil spring 46a and a second coil spring 46b that are expandable and contractible in the central axis direction Y are provided. The first coil spring 46a and the second coil spring 46b both urge the pilot valve body 30 in a direction away from the pilot valve port 25. The second coil spring 46b is located radially outward of the first coil spring 46a, and is arranged such that at least a portion of the first coil spring 46a and the second coil spring 46b overlap when viewed from a direction X perpendicular to the central axis direction Y.

When the pilot valve port 25 transitions from a closed state to an open state, fluid flows into the back pressure chamber 21, and a pressure difference ΔP occurs between the back pressure chamber 21 and the pilot outlet passage 23. Therefore, in order to be able to open the pilot valve port 25 even with the pressure difference ΔP, it is necessary to bias the pilot valve body 30 in the separation direction with a biasing force greater than the pressure difference ΔP. For this reason, as described above, the first coil spring 46a and the second coil spring 46b are provided inside the suction element 44.

<Coil spring assembly structure>
Next, the assembly structure of the first coil spring 46a and the second coil spring 46b will be described in detail with reference to Figures 3 and 4. Figure 3 is a partial vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when de-energized. Figure 4 is a partial vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when energized.

3 and 4, the pilot valve body 30 has a generally cylindrical shape and includes a small diameter portion 30a, a medium diameter portion 30b, and a large diameter portion 30c, each of which has a different diameter along the central axis direction Y. The inner diameter of the small diameter portion 30a is smaller than the inner diameter of the medium diameter portion 30b, and the inner diameter of the medium diameter portion 30b is smaller than the inner diameter of the large diameter portion 30c. The small diameter portion 30a, the medium diameter portion 30b, and the large diameter portion 30c are continuous from the bottom to the top. The pilot valve body 30 also has a first step surface 31 facing downward at the boundary between the small diameter portion 30a and the medium diameter portion 30b, and a second step surface 32 facing downward at the boundary between the medium diameter portion 30b and the large diameter portion 30c. In the central axis direction Y, the first step surface 31 is located closer to the pilot valve port 25 than the second step surface 32, and in the direction X perpendicular to the central axis direction Y, the first step surface 31 is located radially inward than the second step surface 32.

3 and 4, the suction element 44 has a first inner surface 44a, a second inner surface 44b, and a third inner surface 44c that have different diameters along the central axis direction Y. The inner diameter of the first inner surface 44a is larger than the inner diameter of the second inner surface 44b, and the inner diameter of the second inner surface 44b is larger than the inner diameter of the third inner surface 44c. The first inner surface 44a, the second inner surface 44b, and the third inner surface 44c are continuous from the bottom to the top. In addition, the suction element 44 has a third step surface 45 facing downward at the boundary between the first inner surface 44a and the second inner surface 44b.

A support member 47c is provided in the internal space of the attractor 44. The support member 47c is a ring-shaped plate member with a diameter larger than that of the second coil spring 46b, and is fixed and supported by the bottom 48 of the attractor 44. The support member 47c supports the lower ends of the first coil spring 46a and the second coil spring 46b. Therefore, the lower ends of the first coil spring 46a and the second coil spring 46b are abutted against the valve body 10 via the support member 47c.

In addition, a first spring receiving member 47a and a second spring receiving member 47b are provided in the internal space of the suction member 44. The first spring receiving member 47a is ring-shaped with an outer diameter larger than that of the first coil spring 46a, and is provided between the first coil spring 46a and the first step surface 31 of the pilot valve body 30. The second spring receiving member 47b is ring-shaped with an outer diameter larger than that of the second coil spring 46b, and is provided between the second coil spring 46b and the third step surface 45 of the suction member 44. The inner diameter of the second spring receiving member 47b is larger than the diameter of the medium diameter portion 30b and smaller than the diameter of the large diameter portion 30c, so that the inner peripheral side of the second spring receiving member can abut against the second step surface 32, and the outer peripheral side of the second spring receiving member can abut against the third step surface 45. Therefore, the upper end of the first coil spring 46a abuts against the pilot valve body 30 via the first spring bearing member 47a, and the upper end of the second coil spring 46b abuts against the pilot valve body 30 or the attractor 44 via the second spring bearing member 47b.

As shown in FIG. 3, when the solenoid valve is not energized, the electromagnetic coil 41 does not generate an electromagnetic force, and the plunger 42 is not pulled down toward the attractor 44. Therefore, the gap G becomes larger than the predetermined value Gth, the pilot valve body 30 is not pushed down, and the pilot valve port 25 is in an open state. At this time, in the central axis direction Y, the second step surface 32 is located closer to the plunger 42 than the third step surface 45, and the second spring receiving member 47b does not abut against the second step surface 32 but abuts against the third step surface 45. In other words, the first coil spring 46a biases the pilot valve body 30 in a direction away from the pilot valve port 25, but the second coil spring 46b does not bias the pilot valve body 30. The predetermined value Gth is the gap G when the second spring receiving member 49b starts to abut against the second step surface 32 of the pilot valve body 30.

As shown in FIG. 4, when the solenoid valve is energized, the electromagnetic force of the electromagnetic coil 41 is generated, and the plunger 42 is pulled down toward the attractor 44. As a result, the gap G becomes smaller than the predetermined value Gth, and the pilot valve body 30 is pushed down. At this time, in the central axis direction Y, the second step surface 32 is located closer to the pilot valve port 25 than the third step surface 45, and the second spring receiving member 47b does not abut against the third step surface 45 but abuts against the second step surface 32. In other words, the first coil spring 46a and the second coil spring 46b each urge the pilot valve body 30 in a direction away from the pilot valve port 25.

In this way, in the solenoid valve according to this embodiment, when the gap G is equal to or less than the predetermined value Gth, the pilot valve body 30 is biased by the first coil spring 46a and the second coil spring 46b, and when the gap G is greater than the predetermined value Gth, the pilot valve body 30 is biased by the first coil spring 46a. More specifically, the pilot valve body 30 is biased in a direction away from the pilot valve port 25 by the first coil spring 46a via the first spring receiving member 47a at the first step surface 31. Also, when the gap G is equal to or less than the predetermined value Gth, the pilot valve body 30 is biased in a direction away from the pilot valve port 25 by the second coil spring 46b via the inner peripheral side of the second spring receiving member 47b at the second step surface 32. When the gap G is greater than the predetermined value Gth, the outer periphery of the second spring receiving member 47b abuts against the third step surface 45, and the pilot valve body 30 is not biased in the separation direction by the second coil spring 46b.

<Load on pilot valve>
In order to explain the load applied to the pilot valve body of the solenoid valve according to this embodiment, first, the load applied to the pilot valve body of the solenoid valve according to the reference example will be explained with reference to Fig. 5. The solenoid valve according to the reference example is configured to include only the first coil spring 46a out of the first coil spring 46a and the second coil spring 46b in the solenoid valve of this embodiment. Fig. 5 is a graph showing the relationship between the gap and the load of the solenoid valve according to the reference example. In Fig. 5, the horizontal axis shows the gap G, and the vertical axis shows the load F applied to the pilot valve body 30.

In the solenoid valve according to the reference example, the pilot valve body 30 is subjected to a load on the pilot valve port 25 side due to the suction force SF between the plunger 42 and the attractor 44, and a load on the plunger 42 side due to the elastic force S1 of the first coil spring 46a. As shown in FIG. 5, when the gap G becomes smaller, the suction force SF increases nonlinearly and the elastic force S1 increases linearly. In order for the pilot valve body 30 to open the pilot valve port 25, the suction force SF must always be greater than the elastic force S1.

Here, if the pressure difference ΔP between the back pressure chamber 21 and the pilot outflow passage 23 is large when the pilot valve port 25 transitions from a closed state to an open state, it is possible to increase the elastic coefficient of the first coil spring 46a to increase the elastic force S1 to the elastic force S1' so that the pilot valve port 25 can be opened. However, if the elastic force of the first coil spring 46a is increased, as shown in FIG. 5, a section T is created in which the elastic force S1' is greater than the suction force SF, and the pilot valve port 25 cannot be closed. Therefore, in order to increase the elastic force of the first coil spring 46a, the suction force SF between the plunger 42 and the suction element 44 must also be increased, which would result in an increase in the size of the solenoid valve.

Next, the load applied to the pilot valve body of the solenoid valve according to this embodiment will be described with reference to FIG. 6. FIG. 6 is a graph showing the relationship between the gap and the load of the solenoid valve according to the embodiment of the present disclosure. In FIG. 6, the horizontal axis shows the gap G, and the vertical axis shows the load F applied to the pilot valve body 30.

In the solenoid valve 1 according to the embodiment of the present disclosure, the pilot valve body 30 is subjected to a load on the pilot valve port 25 side due to the suction force SF between the plunger 42 and the suction element 44, and a load on the plunger 42 side due to the elastic force S1 of the first coil spring 46a and the elastic force S2 of the second coil spring 46b. As shown in FIG. 6, the first coil spring 46a exerts the elastic force S1 at the full stroke, while the second coil spring 46b exerts the elastic force S2 when the gap G is equal to or less than a predetermined value Gth. Therefore, the elastic force can be suppressed to the elastic force S1 in the range where the gap G is greater than the predetermined value Gth, and the elastic force can be increased to the elastic force S1+S2 in the range where the gap G is equal to or greater than 0 and equal to or less than Gth. Here, the elastic coefficient of the first coil spring 46a may be smaller than the elastic coefficient of the second coil spring 46b at least in the range where the gap G is equal to or greater than 0 and equal to or less than Gth. 5 and 6, gap G1 indicates the gap G when the solenoid valve 1 is closed, and gap G2 indicates the gap G when the solenoid valve 1 is open. Also, the full stroke of the first coil spring 46a refers to the compression length of the first coil spring 46a until the solenoid valve 1 transitions from an open state to a closed state.

In this way, when the pilot valve port 25 transitions from a closed state to an open state, it is possible to open the pilot valve port 25 even if the pressure difference ΔP between the back pressure chamber 21 and the pilot outflow passage 23 is large, and since the biasing force of the coil spring on the pilot valve body 30 is always smaller than the suction force SF of the suction element 44, there is no need to increase the suction force SF. Therefore, the pilot valve port 25 can be opened and closed without increasing the size of the solenoid valve 1.

Although the embodiment of the present disclosure has been described above, it goes without saying that the technical scope of the present disclosure should not be interpreted as being limited by the description of the present embodiment. The present embodiment is merely an example, and it will be understood by those skilled in the art that various modifications of the embodiment are possible within the scope of the invention described in the claims. The technical scope of the present disclosure should be determined based on the scope of the invention described in the claims and its equivalents.

1: Solenoid valve 10: Valve body 11: Main valve chamber 12: Inlet passage 13: Outlet passage 14: Main valve seat 20: Main valve body 21: Back pressure chamber 22: Pilot inlet passage 23: Pilot outlet passage 24: Pilot valve seat 25: Pilot valve port 30: Pilot valve body 30a: Small diameter section 30b: Medium diameter section 30c: Large diameter section 31: First step surface 32: Second step surface 40: Drive section 41: Solenoid coil 42: Plunger 43: Valve shaft 44: Attractor 44a: First inner surface 44b: Second inner surface 44c: Third inner surface 45: Third step surface 46a: First coil spring 46b: Second coil spring 47a: First spring bearing member 47b: Second spring bearing member 47c: Support member 48: Bottom 49: Cylindrical support section

Claims (7)

a valve body including an inlet passage communicating with a main valve chamber, a main valve seat disposed within the main valve chamber, and an outlet passage;
a main valve body that is provided with a pilot valve port and is capable of opening and closing the outflow path by being seated on or separated from the main valve seat;
a pilot valve body capable of opening and closing the pilot valve port;
a drive unit capable of driving the pilot valve body;
Equipped with
The drive unit is
An electromagnetic coil;
A plunger movable along a central axis of the electromagnetic coil;
an attractor fixed to the valve body and capable of attracting the plunger by the electromagnetic force of the electromagnetic coil;
a first coil spring and a second coil spring that bias the pilot valve body in a direction away from the pilot valve port;
having
When a gap between the plunger and the attractor in the central axial direction is equal to or smaller than a predetermined value, the pilot valve body is biased by the first coil spring and the second coil spring,
When the gap is larger than the predetermined value, the pilot valve element is biased by the first coil spring. The first coil spring exerts an elastic force over a full stroke,
The solenoid valve according to claim 1 , wherein the second coil spring exerts an elastic force when the gap is equal to or smaller than the predetermined value. The solenoid valve according to claim 1, wherein the first coil spring and the second coil spring are arranged so that at least a portion of them overlap when viewed from a direction perpendicular to the central axis direction. The solenoid valve according to claim 1, wherein the elastic modulus of the first coil spring is smaller than the elastic modulus of the second coil spring. the drive unit includes a ring-shaped first spring receiving member that receives an elastic force of the first coil spring, and a ring-shaped second spring receiving member that receives an elastic force of the second coil spring,
the pilot valve body has a first step surface against which the first spring bearing member abuts, and a second step surface that is located outside the first step surface and against which an inner peripheral side of the second spring bearing member abuts,
the suction element has a third step surface against which an outer circumferential side of the second spring receiving member abuts,
The pilot valve body is
the first step surface is biased in the separating direction by the first coil spring via the first spring receiving member,
When the gap is equal to or smaller than a predetermined value, the second step surface is biased in the separating direction by the second coil spring via an inner peripheral side of the second spring receiving member,
2. The solenoid valve according to claim 1, wherein when the gap is larger than the predetermined value, an outer circumferential side of the second spring receiving member abuts against the third step surface, and is not biased in the separating direction by the second coil spring. When the electromagnetic coil is energized, the second step surface is located closer to the pilot valve port than the third step surface,
The solenoid valve according to claim 5 , wherein the second step surface is located closer to the plunger than the third step surface when the electromagnetic coil is not energized. the driving unit has a ring-shaped support member that supports the first coil spring and the second coil spring,
The solenoid valve according to claim 1 , wherein the first coil spring and the second coil spring are in contact with the valve body via the support member.

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