Solenoid valve

Abstract

To provide a compact solenoid valve capable of being opened and closed even if a differential pressure is high.SOLUTION: A solenoid valve 1 includes: a valve body 10 which has an inflow passage 12 communicating with a main valve chamber 11, a main valve seat 14 arranged in the main valve chamber 11, and an outflow passage 13; a main valve element 20 which has a pilot valve port 25, and can open and close the outflow passage 13 by being seated on or separated from the main valve seat 14; a pilot valve element 30 which can open and close the pilot valve port 25; and a drive unit 40 which can drive the pilot valve element 30. The drive unit 40 includes an electromagnetic coil 41, a plunger 42 which can be moved in a center axis direction Y of the electromagnetic coil 41, an attractor 44 which is fixed to the valve body 10 and can attract the plunger 42 by electromagnetic force of the electromagnetic coil 41, and a first coil spring 46a and a second coil spring 46b for energizing the pilot valve element 30 in a separating direction in which the pilot valve element 30 is separated from the pilot valve port 25.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to solenoid valves. [Background technology]

[0002] A solenoid valve of the energized-close type is known in which, when the electromagnetic coil is energized, the attractive force between the plunger and the attractor pushes the pilot valve element 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 element up from the pilot valve port to open the valve (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-112146 Summary of the Invention [Problem to be solved by the invention]

[0004] To enable the valve to open even when the differential pressure between the pilot inlet and outlet passages is high, the elastic force of the coil spring must be increased. However, increasing the elastic force of the coil spring requires increasing the attractive force between the plunger and the attractor to close the valve, which creates the problem of increasing the size of the solenoid valve.

[0005] An object of the present disclosure is to provide a small solenoid valve that can be opened and closed even under high differential pressure. [Means for solving the problem]

[0006] 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 has 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 element; Equipped with The drive unit is An electromagnetic coil; a plunger movable along the 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 element in a direction away from the pilot valve port; and When a gap, which is a distance between the plunger and the attractor in the central axis direction, is equal to or smaller than a predetermined value, the pilot valve element 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. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a small solenoid valve that can be opened and closed even under high differential pressure. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view of a solenoid valve according to an embodiment of the present disclosure when not energized; [Figure 2] FIG. 2 is a longitudinal cross-sectional view of the electromagnetic valve according to the embodiment of the present disclosure when energized. [Figure 3] FIG. 2 is a partial vertical cross-sectional view of the solenoid valve according to the embodiment of the present disclosure when not energized. [Figure 4] FIG. 2 is a partial vertical cross-sectional view of the electromagnetic valve according to the embodiment of the present disclosure when energized. [Figure 5] 10 is a graph showing the relationship between the gap and the load of the solenoid valve according to the reference example. [Figure 6] 4 is a graph showing the relationship between the gap and the load of the solenoid valve according to the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For the sake of convenience, the description of components having the same reference numerals as those already described in the description of the embodiments will be omitted. In the following description of the embodiments, the up-down direction indicates the direction within the paper plane of Figures 1 to 4, and this is not intended to narrow the technical scope of the present disclosure.

[0010] <Internal structure of a 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 an embodiment of the present disclosure when not energized. Figure 2 is a vertical cross-sectional view of the solenoid valve according to an embodiment of the present disclosure when energized.

[0011] 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 includes 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.

[0012] The valve body 10 is a substantially cylindrical member extending in the central axis direction Y, and has an internal space that houses the main valve element 20. The internal space is divided by the main valve element 20 into a main valve chamber 11 located below the main valve element 20, and a back pressure chamber 21 located above the main valve element 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.

[0013] The main valve element 20 has a generally cylindrical shape extending in the central axis direction Y, and is provided so as to be movable up and down within the internal space of the valve body 10. The main valve element 20 can open and close the outflow path 13 by being seated on or separated from the main valve seat 14. Therefore, when the main valve element 20 is in an open state, the fluid that has flowed in from the inlet path 12 flows out into the outflow path 13 via the main valve chamber 11, and when the main valve element 20 is in a closed state, the fluid remains in the main valve chamber 11 without flowing out into the outflow path 13.

[0014] The main valve element 20 has a pilot inlet passage 22 extending 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 element 20 also has a pilot outlet passage 23 extending 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 element 20 so as to surround the pilot valve port 25.

[0015] The pilot valve element 30 has a generally cylindrical shape and can open and close the pilot valve port 25 by being seated on or separated from the pilot valve seat 24. The pilot valve element 30 is disposed inside the attractor 44 and is connected to the plunger 42 via the valve stem 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 outflow path 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 outflow path 23.

[0016] The drive unit 40 includes an electromagnetic coil 41, a plunger 42, a valve stem 43, an attractor 44, and a cylindrical support portion 49. The plunger 42 is supported by the cylindrical support portion 49 inside the electromagnetic coil 41 so as to be movable up and down. The attractor 44 has a generally cylindrical shape and is disposed so as to face the plunger 42 in the vertical direction, and is fixedly supported by the cylindrical support portion 49 and the valve body 10. The valve stem 43 has a generally columnar shape extending in the central axis direction Y, and an upper portion of the valve stem 43 is fixed to the plunger 42, while a lower portion of the valve stem 43 is disposed inside the attractor 44 so as to be movable up and down. The electromagnetic coil 41 is connected to an external power source (not shown), and applying a drive current to the electromagnetic coil 41 generates an electromagnetic force that attracts the plunger 42 and the attractor 44 to each other. 2, the plunger 42 is pulled down toward the attractor 44 by the electromagnetic force, which pushes down the pilot valve element 30 via the valve stem 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 gap G, then gap G becomes small.

[0017] 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 in the space between the attractor 44 and the pilot valve element 30. The first coil spring 46a and the second coil spring 46b both urge the pilot valve element 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 disposed 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 that is perpendicular to the central axis direction Y.

[0018] When the pilot valve port 25 transitions from a closed state to an open state, fluid flows into the back pressure chamber 21, generating a pressure difference ΔP between the back pressure chamber 21 and the pilot outlet path 23. Therefore, in order to be able to open the pilot valve port 25 even when the pressure difference ΔP exists, it is necessary to urge the pilot valve element 30 in the separating direction with a force greater than the pressure difference ΔP. For this reason, the first coil spring 46a and the second coil spring 46b are provided inside the attractor 44, as described above.

[0019] <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.

[0020] 3 and 4, the pilot valve element 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 having 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, which 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 bottom to top. The pilot valve element 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.

[0021] 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, which 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 bottom to top. The suction element 44 also has a third step surface 45 facing downward at the boundary between the first inner surface 44a and the second inner surface 44b.

[0022] 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 fixedly 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 abut against the valve body 10 via the support member 47c.

[0023] A first spring receiving member 47a and a second spring receiving member 47b are provided in the internal space of the attractor 44. The first spring receiving member 47a is ring-shaped and has an outer diameter larger than that of the first coil spring 46a, and is provided between the first coil spring 46a and the first stepped surface 31 of the pilot valve body 30. The second spring receiving member 47b is ring-shaped and has an outer diameter larger than that of the second coil spring 46b, and is provided between the second coil spring 46b and the third stepped surface 45 of the attractor 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 circumferential side of the second spring receiving member can abut against the second stepped surface 32, and the outer circumferential side of the second spring receiving member can abut against the third stepped surface 45. Therefore, the upper end of the first coil spring 46a abuts against the pilot valve body 30 via the first spring receiving 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 receiving member 47b.

[0024] As shown in FIG. 3 , when the solenoid valve is de-energized, the electromagnetic coil 41 does not generate electromagnetic force, and the plunger 42 is not pulled downward toward the attractor 44. Therefore, the gap G exceeds a predetermined value Gth, the pilot valve element 30 is not depressed, and the pilot valve port 25 is open. 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 rather the third step surface 45. In other words, the first coil spring 46a biases the pilot valve element 30 in the direction away from the pilot valve port 25, but the second coil spring 46b does not bias the pilot valve element 30. The predetermined value Gth is the gap G when the second spring receiving member 49b begins to abut against the second step surface 32 of the pilot valve element 30.

[0025] 4, when the solenoid valve is energized, an electromagnetic force is generated in the electromagnetic coil 41, and the plunger 42 is pulled down toward the attractor 44. As a result, the gap G becomes smaller than a predetermined value Gth, and the pilot valve element 30 is pushed down. At this time, in the central axis direction Y, the second step surface 32 is positioned 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 element 30 in a direction away from the pilot valve port 25.

[0026] As described above, in the solenoid valve according to this embodiment, when the gap G is equal to or smaller than the predetermined value Gth, the pilot valve element 30 is biased by the first coil spring 46a and the second coil spring 46b. When the gap G is larger than the predetermined value Gth, the pilot valve element 30 is biased by the first coil spring 46a. More specifically, the pilot valve element 30 is biased at the first step surface 31 by the first coil spring 46a via the first spring receiving member 47a in a direction away from the pilot valve port 25. When the gap G is equal to or smaller than the predetermined value Gth, the pilot valve element 30 is biased at the second step surface 32 by the second coil spring 46b via the inner peripheral side of the second spring receiving member 47b in a direction away from the pilot valve port 25. When the gap G is larger than the predetermined value Gth, the outer peripheral side of the second spring receiving member 47b abuts against the third step surface 45, and therefore the pilot valve element 30 is not biased in the direction away by the second coil spring 46b.

[0027] <Load on the pilot valve> To explain the load acting on the pilot valve element of the solenoid valve according to this embodiment, first, the load acting on the pilot valve element of a solenoid valve according to a reference example will be explained using 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 represents the gap G, and the vertical axis represents the load F acting on the pilot valve element 30.

[0028] In the solenoid valve according to the reference example, the pilot valve element 30 is subjected to a load toward the pilot valve port 25 due to the attractive force SF between the plunger 42 and the attractor 44, and a load toward the plunger 42 due to the elastic force S1 of the first coil spring 46a. As shown in Fig. 5, as the gap G becomes smaller, the attractive force SF increases nonlinearly and the elastic force S1 increases linearly. In order for the pilot valve element 30 to open the pilot valve port 25, the attractive force SF must always be greater than the elastic force S1.

[0029] Here, if the pressure difference ΔP between the backpressure chamber 21 and the pilot outflow path 23 is large when the pilot valve port 25 transitions from a closed state to an open state, it is conceivable to increase the elastic coefficient of the first coil spring 46a to increase the elastic force S1 to an elastic force S1' so as to open the pilot valve port 25. However, if the elastic force of the first coil spring 46a is increased, a section T will be created in which the elastic force S1' is greater than the attractive force SF, as shown in Figure 5, and the pilot valve port 25 will not be closed. Therefore, in order to increase the elastic force of the first coil spring 46a, the attractive force SF between the plunger 42 and the attractor 44 must also be increased, which would result in an increase in the size of the solenoid valve.

[0030] Next, the load applied to the pilot valve element 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 represents the gap G, and the vertical axis represents the load F applied to the pilot valve element 30.

[0031] In the solenoid valve 1 according to the embodiment of the present disclosure, the pilot valve element 30 is subjected to a load toward the pilot valve port 25 due to the attractive force SF between the plunger 42 and the attractor 44, and a load toward the plunger 42 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 throughout the entire 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 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. 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.

[0032] 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 path 23 is large, and since the biasing force of the coil spring on the pilot valve body 30 is always smaller than the attractive force SF of the attractor 44, there is no need to increase the attractive force SF. Therefore, the pilot valve port 25 can be opened and closed without increasing the size of the solenoid valve 1.

[0033] Although the embodiments of the present disclosure have 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 embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments 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. [Explanation of symbols]

[0034] 1: Solenoid valve 10: Valve body 11: Main valve chamber 12:Inflow channel 13:Outflow channel 14: Main valve seat 20: Main valve body 21:Back pressure chamber 22: Pilot inlet 23: Pilot outlet 24: Pilot valve seat 25: Pilot valve port 30: Pilot valve body 30a: Small diameter part 30b: Medium diameter part 30c: Large diameter section 31: First step surface 32:Second step surface 40: Drive unit 41: Electromagnetic coil 42: Plunger 43: Valve stem 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: Cylinder support part

Claims

1. 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 has 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 element; Equipped with The drive unit is An electromagnetic coil; a plunger movable along the 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 element in a direction away from the pilot valve port; and When a gap, which is a distance between the plunger and the attractor in the central axis direction, is equal to or smaller than a predetermined value, the pilot valve element 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.

2. The first coil spring exerts elastic force over the entire 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.

3. 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 each of the first coil spring and the second coil spring overlaps with each other when viewed from a direction perpendicular to the central axis direction.

4. 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.

5. the drive unit includes a ring-shaped first spring bearing member that receives an elastic force of the first coil spring and a ring-shaped second spring bearing 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 outward from the first step surface and against which an inner peripheral side of the second spring bearing member abuts, the suction element has a third stepped surface against which an outer circumferential surface of the second spring receiving member abuts, The pilot valve body 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, the outer circumferential side of the second spring receiving member abuts against the third step surface, and the second spring receiving member is not biased in the separating direction by the second coil spring.

6. 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.

7. the drive unit includes 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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