Electronic Expansion Valve

Abstract

To provide an electronic expansion valve capable of suppressing an increase in the size of the electronic expansion valve.SOLUTION: An electronic expansion valve 1 includes a valve seat 11 provided with a through-hole 11a through which cooling medium passes, and a valve element 12, the through-hole 11a of the valve seat 11 being arranged at a position offset a predetermined distance from a working center G where force works on the valve element 12 to move from a moving mechanism 13 in the direction of separating from the valve seat 11 in view from the moving direction of the valve element 12.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electronic expansion valve, and more particularly to an electronic expansion valve including a valve body configured to allow refrigerant to flow through a through hole when the valve body moves away from a valve seat. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known an electronic expansion valve having a valve body configured to allow refrigerant to flow through a through-hole by separating from a valve seat (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses an electronic expansion valve including an armature including a valve body, a valve seat with an orifice provided on the central axis, and a solenoid including an iron core and a coil. The electronic expansion valve of Patent Document 1 is configured so that when the solenoid is energized, the armature is attracted, and the valve body moves away from the valve seat, causing refrigerant to flow through the orifice. Furthermore, Patent Document 1 discloses that the electronic expansion valve is used in a refrigeration cycle, is disposed between a condenser and an evaporator, and expands the refrigerant flowing into the evaporator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-196596 Summary of the Invention [Problem to be solved by the invention]

[0005] Although not disclosed in Patent Document 1, in an electronic expansion valve used in a refrigeration cycle, a suction force is applied to the valve element that draws it toward the valve seat due to the pressure difference between the high-pressure refrigerant on the condenser side and the low-pressure refrigerant on the evaporator side. Therefore, when separating the valve element from the valve seat, the force moving the valve element (valve opening force) must be greater than the suction force caused by the pressure difference. In particular, when using a high-flow, high-pressure refrigerant, the suction force caused by the pressure difference becomes greater, so the valve opening force must be increased. One idea is to increase the suction force of the movement mechanism (solenoid), but increasing the coil size would increase the size of the movement mechanism, which poses the problem of the electronic expansion valve becoming larger.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an electronic expansion valve that can prevent the electronic expansion valve from becoming large. [Means for solving the problem]

[0007] An electronic expansion valve according to one aspect of the present invention is an electronic expansion valve used in a refrigeration cycle in which a refrigerant circulates, and comprises: a valve seat provided with a through-hole through which the refrigerant passes; a valve element arranged to face the valve seat and configured to block the through-hole by contacting the valve seat and to allow the refrigerant to flow through the through-hole by moving away from the valve seat; a valve element that is tiltable relative to the valve seat; and a movement mechanism including an electromagnet that moves the valve element in a direction away from the valve seat by magnetic force; and a biasing member that moves the valve element in a direction approaching the valve seat, wherein the through-hole of the valve seat is arranged at a position offset by a predetermined distance from the center of action of a force acting from the movement mechanism to move the valve element in a direction away from the valve seat, as viewed in the movement direction of the valve element. At least one of the valve seat and the valve body includes a first protrusion provided at a position corresponding to the through hole, and at least one of the valve seat and the valve body includes a second protrusion provided at a position different from the first protrusion when viewed in the movement direction of the valve body. .

[0008] In one aspect of the present invention, the electronic expansion valve has the valve disc tiltable relative to the valve seat, and the through-hole in the valve seat is positioned offset a predetermined distance from the center of force acting from the moving mechanism to move the valve disc away from the valve seat, as viewed in the direction of movement of the valve disc. This offsets the center of force acting to move the valve disc away from the valve seat from the position of the through-hole, which is the center of force acting to attract the valve disc toward the valve seat due to the pressure difference between the refrigerant. Therefore, when the valve disc is moved away from the valve seat, the valve disc tilts, forming a gap between the valve disc and the through-hole. Since the refrigerant flows into the gap formed between the valve disc and the through-hole, the pressure difference is reduced, eliminating the need for a large force to move the valve disc. This eliminates the need for a large moving mechanism, thereby preventing the electronic expansion valve from becoming too large.

[0009] In the electronic expansion valve according to the above aspect, the valve disc is preferably configured to be separated from the valve seat by tilting. With this configuration, tilting the valve disc reliably forms a gap between the valve disc and the through-hole, allowing refrigerant to flow into the gap between the valve disc and the valve seat, reducing the pressure difference acting on the valve disc and making it easy to separate the valve disc from the valve seat.

[0010] In the electronic expansion valve according to the above aspect, the valve seat is preferably positioned at a position offset a predetermined distance from the center of action of the valve disc in the direction of movement of the valve disc, and includes a first protrusion having a through-hole and configured to protrude toward the valve disc. With this configuration, the valve disc and the valve seat contact each other via the first protrusion, thereby reducing the contact area between the valve disc and the valve seat compared to when the valve disc and the valve seat contact each other over the entire opposing surfaces. Here, the force acting on the valve disc is calculated as the product of pressure and area. Therefore, by reducing the contact area between the valve disc and the valve seat, the suction force acting on the valve disc due to the pressure difference can be reduced compared to when the valve disc and the valve seat contact each other over the entire opposing surfaces, thereby reducing the suction force required when the moving mechanism separates the valve disc from the valve seat. Furthermore, since the valve disc and the valve seat contact each other via the first protrusion, the valve disc and the valve seat can be positioned in an unstable state, making it easier to tilt the valve disc when separating it from the valve seat.

[0011] In this case, the first protrusion is preferably provided at a position that does not overlap with the center of action when viewed in the direction of movement of the valve disc. With this configuration, the surface of the first protrusion where the valve disc and the valve seat come into contact does not overlap with the center of action when viewed in the direction of movement of the valve disc, so that the range in which suction force due to the pressure difference of the refrigerant acts on the valve disc and the center of action of the movement mechanism can be reliably offset. As a result, the movement mechanism can be prevented from being affected by the suction force due to the pressure difference of the refrigerant.

[0012] In the electronic expansion valve including the first protrusion, preferably , th The first protrusion and the second protrusion have the same protrusion height, and the second protrusion is located on the opposite side of the center of action to the first protrusion. With this configuration, the provision of the second protrusion allows the valve disc to be stably positioned relative to the valve seat, thereby preventing the valve disc from tilting and causing refrigerant to flow to the valve seat when the electronic expansion valve is closed.

[0013] In this case, preferably, the valve seat includes a second protrusion, and the second protrusion does not have a through-hole. With this configuration, the first protrusion and the second protrusion are disposed on the valve seat, which makes it easier to adjust the positions of the first protrusion and the second protrusion compared to when the second protrusion is disposed on the valve body. Furthermore, when a through-hole is provided in the second protrusion, the resultant force of the suction force due to the pressure difference of the refrigerant acting on the valve body at the first protrusion and the suction force due to the pressure difference of the refrigerant acting on the valve body at the second protrusion acts on the valve body. Therefore, by not providing a through-hole in the second protrusion, it is possible to prevent the suction force due to the pressure difference of the refrigerant from increasing, thereby preventing the movement mechanism from becoming larger in size due to the increased suction force of the movement mechanism.

[0014] The electronic expansion valve according to the above aspect preferably further comprises an annular member disposed around the valve disc and defining a refrigerant passage between the valve disc and its outer peripheral surface, the valve disc being tiltable by a gap between the inner peripheral surface of the annular member and the outer peripheral surface of the valve disc. With this configuration, the size of the refrigerant passage is set by the size of the gap between the inner peripheral surface of the annular member and the outer peripheral surface of the valve disc, so that the amount of refrigerant can be set to a constant amount by the size of the inner diameter of the annular member. Furthermore, by reducing the size of the gap between the inner peripheral surface of the annular member and the outer peripheral surface of the valve disc, it is possible to prevent the valve disc from tilting significantly.

[0015] In the electronic expansion valve according to the above aspect, the center of action is preferably located at the center of gravity of the valve disc, and the through-hole is located at a position offset a predetermined distance from the center of gravity of the valve disc as viewed in the direction of movement of the valve disc. With this configuration, the center of gravity, which is the center of action at which a force acting to move the valve disc away from the valve seat acts when the valve disc separates from the valve seat, can be offset from the position of the through-hole, which is the center at which a suction force due to a pressure difference in the refrigerant acts, so that when the valve disc separates from the valve seat, the valve disc tilts and a gap is formed between the valve disc and the through-hole. As a result, refrigerant flows into the gap between the valve disc and the valve seat, reducing the pressure difference acting on the valve disc, and the valve disc can be easily separated from the valve seat. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an electronic expansion valve that can prevent the electronic expansion valve from becoming large. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing an example of a showcase in which an electronic expansion valve is used. [Figure 2] FIG. 2 is a block diagram showing a refrigeration cycle. [Figure 3] FIG. 2 is a cross-sectional view of an electronic expansion valve. [Figure 4] FIG. 2 is a schematic diagram showing the electronic expansion valve in a closed state. [Figure 5] FIG. 4 is a schematic diagram for explaining positions where through holes are arranged. [Figure 6] FIG. 10 is a schematic diagram showing a state in which the valve body separates from the valve seat. [Figure 7] FIG. 10 is a partially enlarged view showing the valve body moving away from the valve seat. [Figure 8] FIG. 2 is a schematic diagram illustrating an open state of the electronic expansion valve. DETAILED DESCRIPTION OF THE INVENTION

[0018] An example in which the electronic expansion valve 1 of the present invention is used in a refrigeration cycle 100a will be described.

[0019] (Cooling device configuration) As shown in Fig. 1, the refrigeration cycle 100a is configured to circulate a refrigerant and perform heat exchange to cool an object to be cooled. The refrigeration cycle 100a of this embodiment is used to cool air flowing through a plurality of showcases 100, which are cooling devices. The refrigerant is, for example, R410A, R408A, or carbon dioxide (CO2).

[0020] 1 and 2, the refrigeration cycle 100a includes an electronic expansion valve 1, an evaporator 2, a compressor 3, and a condenser 4. When cooling a plurality of showcases 100, an electronic expansion valve 1 and an evaporator 2 are provided for each showcase 100, and the refrigerant condensed by the condenser 4 is distributed to the electronic expansion valve 1 for each showcase 100. The evaporated refrigerant from the evaporator 2 for each showcase 100 is then collected and flows into the compressor 3.

[0021] The electronic expansion valve 1 is configured to expand a high-pressure liquid-phase refrigerant condensed by the condenser 4. In this embodiment, the electronic expansion valve 1 is a pulse type. The detailed structure of the electronic expansion valve 1 will be described later.

[0022] The evaporator 2 is configured to evaporate the refrigerant that has been expanded by the electronic expansion valve 1 and is now in a low-pressure, gas-liquid two-phase state. Specifically, the refrigerant is evaporated by exchanging heat with the air to be cooled and receiving heat from the air to be cooled. The air cooled by the evaporator 2 cools the shelves 101 in the showcase 100.

[0023] The compressor 3 is configured to compress the gas phase refrigerant evaporated in the evaporator 2 to produce a high pressure refrigerant.

[0024] The condenser 4 is configured to cool the refrigerant discharged from the compressor 3 and condense it into a high-pressure liquid-phase refrigerant.

[0025] (Structure of an electronic expansion valve) As shown in Fig. 3, the electronic expansion valve 1 includes a valve seat 11, a valve element 12, a moving mechanism 13, an annular member 14, a housing 15, a first pipe 16, and a second pipe 17. The electronic expansion valve 1 is configured so that refrigerant condensed in the condenser 4 is supplied into the housing 15 via the first pipe 16. The moving mechanism 13 moves the valve element 12 away from the valve seat 11, thereby supplying the refrigerant to the evaporator 2 via the second pipe 17. In this embodiment, the valve element 12 moves in the vertical direction. The direction in which the valve element 12 moves is defined as the Z direction.

[0026] In the electronic expansion valve 1, when the valve seat 11 and the valve element 12 are in contact with each other, the through-hole 11a is blocked and the refrigerant does not flow to the evaporator 2 (see FIG. 2). When the valve element 12 and the valve seat 11 are separated from each other, the through-hole 11a is open and the refrigerant flows. At this time, due to the pressure difference between the high-pressure refrigerant supplied from the condenser 4 and the refrigerant that has evaporated in the evaporator 2 and changed to a low-pressure refrigerant, the refrigerant is sucked into the through-hole 11a and flows into the second pipe 17. Note that the refrigerant changes from a liquid phase to a gas-liquid two-phase state as it flows into the through-hole 11a.

[0027] As shown in Fig. 4, the valve seat 11 is provided with a through hole 11a, a first protrusion 11b, and a second protrusion 11c. The valve seat 11 is made of non-magnetic austenitic stainless steel. The valve seat 11 has a circular shape when viewed in the movement direction (Z direction) of the valve disc 12. For convenience, hatching indicating a cross section of the valve seat 11 is omitted from Fig. 4.

[0028] As shown in FIG. 5, the through hole 11a is disposed at a position offset by a predetermined distance from the center of action G, at which a force acts from the movement mechanism 13 (see FIG. 4) to move the valve disc 12 in a direction away from the valve seat 11 (Z1 direction), as viewed in the movement direction (Z direction) of the valve disc 12. The center of action G is located at the center of gravity of the valve disc 12. In FIG. 5, the valve disc 12 as viewed from the Z1 side is schematically represented by a circle, and the center of the circle is the center of action G. In FIG. 5, the through hole 11a is offset in the X direction, but it may be offset in the Y direction in addition to or instead of the X direction. The predetermined distance is, for example, a distance at which the through hole 11a can be disposed so that the center of action G and the through hole 11a do not overlap as viewed in the movement direction (Z direction) of the valve disc 12.

[0029] 4, the first protrusion 11b is provided on the surface of the valve seat 11 facing the valve element 12, and protrudes toward the valve element 12. The first protrusion 11b is provided with a through-hole 11a. The first protrusion 11b has a circular shape when viewed in the movement direction (Z direction) of the valve element 12.

[0030] 5, the first protrusion 11b is disposed at a position offset by a predetermined distance from the center of action G when viewed in the movement direction (Z direction) of the valve body 12. Furthermore, the first protrusion 11b is provided at a position that does not overlap with the center of action G when viewed in the movement direction (Z direction) of the valve body 12.

[0031] As shown in Fig. 4, the second protrusion 11c protrudes toward the valve body 12. Like the first protrusion 11b, the second protrusion 11c is provided on the surface of the valve seat 11 facing the valve body 12. The second protrusion 11c does not have a through-hole 11a. The protrusion height (length in the Z direction) of the first protrusion 11b and the protrusion height (length in the Z direction) of the second protrusion 11c are the same.

[0032] 5, the second protrusion 11c is disposed on the opposite side of the first protrusion 11b with respect to the center of action G. One second protrusion 11c is provided. The second protrusion 11c has a circular shape when viewed in the movement direction (Z direction) of the valve body 12.

[0033] As shown in FIG. 3, the valve element 12 faces the movement mechanism 13. The valve element 12 is moved in the vertical direction (Z direction) by the movement mechanism 13. The valve element 12 faces the valve seat 11 in the vertical direction (Z direction). The valve element 12 is made of ferritic stainless steel, which is easily magnetized. The valve element 12 is provided so as to be tiltable relative to the valve seat 11. In the vertical direction (Z direction), the surface of the valve element 12 facing the valve seat 11 is flat. The valve element 12 is provided so as to be tiltable relative to the valve seat 11 by the gap between the inner peripheral surface of the annular member 14 and the outer peripheral surface 12a of the valve element 12 (see FIG. 4). The valve element 12 is configured to be separated from the valve seat 11 by tilting. The valve element 12 has a circular shape when viewed in the movement direction (Z direction) of the valve element 12.

[0034] The moving mechanism 13 includes an electromagnet 13a consisting of an iron core and a coil, and a biasing member 13b. The electromagnet 13a has an iron core inserted in the center of the coil. When the coil is energized, the electromagnet 13a generates a magnetic force, attracting the valve element 12 and separating the valve element 12 from the valve seat 11, thereby opening the electronic expansion valve 1. When the coil is not energized, the biasing member 13b presses the valve element 12 against the valve seat 11, substantially sealing the through-hole 11a and closing the electronic expansion valve 1. The electromagnet 13a is located above (on the Z1 side of) the valve element 12. The biasing member 13b is attached to a portion of the upper surface (the surface on the Z1 side) of the valve element 12. The biasing member 13b is a spring. The attractive force of the electromagnet 13a is greater than the biasing force of the biasing member 13b.

[0035] As shown in Fig. 4, the annular member 14 is provided around the valve body 12. A portion of the Z2 side of the movement mechanism 13 comes into contact with the annular member 14. A refrigerant passage is formed between the annular member 14 and the outer peripheral surface 12a of the valve body 12. The refrigerant from the condenser 4 flows into the annular member 14 via the first piping 16. The refrigerant is supplied throughout the housing along the annular member 14.

[0036] The housing 15 has a circular shape when viewed in the movement direction (Z direction) of the valve element 12. The housing 15 has an opening on the Z1 side, and the annular member 14 is attached to the opening. The valve seat 11 and the valve element 12 are disposed inside the housing 15. A first pipe 16 connected to the condenser 4 and a second pipe 17 connected to the evaporator 2 are attached to the Z2 side of the housing 15.

[0037] (Opening and closing of electronic expansion valve) The movement of the opening and closing operation of the electronic expansion valve 1 will be described with reference to Figures 4 and 6 to 8. Note that the following description will be given of the case where the electronic expansion valve 1 changes from a closed state to an open state and then returns to the closed state. Note that hatching indicating a cross section of the valve seat 11 is omitted in Figures 4 and 6 to 8.

[0038] As shown in FIG. 4, in the closed state, the valve element 12 is biased in the Z2 direction by the biasing member 13b and is in contact with the valve seat 11.

[0039] When the coil of the electromagnet 13a is energized, a magnetic force is generated between the iron core and the coil, and the magnetic force attracts the valve element 12, causing the valve element 12 to start moving in the Z1 direction, which is opposite to the biasing direction of the biasing member 13b.

[0040] As shown in FIG. 6, the valve body 12 is attracted by the magnetic force of the electromagnet 13a and tilts relative to the first protrusion 11b.

[0041] As shown in Fig. 7, when the valve element 12 is tilted, a gap is formed between the valve element 12 and the first protrusion 11b, and the refrigerant flows in as shown by the arrow. This reduces the pressure of the refrigerant toward the valve element 12. Note that the angle of tilt is exaggerated in Fig. 7 for ease of explanation.

[0042] As shown in Figure 8, the valve element 12 moves away from the valve seat 11, opening the through-hole 11a. The valve element 12 tilts when it starts to move, but then remains substantially horizontal as it is attracted by the electromagnet 13a. The biasing member 13b is pushed toward the Z1 side and deformed. This causes the electronic expansion valve 1 to enter the open state.

[0043] When the supply of electricity to the coil of the electromagnet 13a is stopped, the valve element 12 is urged by the urging member 13b and comes into contact with the valve seat 11, and the electronic expansion valve 1 is brought into a closed state.

[0044] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0045] In this embodiment, the electronic expansion valve 1 is an electronic expansion valve 1 used in a refrigeration cycle 100a in which a refrigerant circulates, and includes: a valve seat 11 having a through hole 11a through which the refrigerant passes; a valve element 12 arranged opposite the valve seat 11 and configured to block the through hole 11a by coming into contact with the valve seat 11 and to allow the refrigerant to flow through the through hole 11a by moving away from the valve seat 11; and a moving mechanism 13 including an electromagnet 13a that moves the valve element 12 in a direction away from the valve seat 11 by magnetic force and a biasing member 13b that moves the valve element 12 in a direction toward the valve seat 11. The through hole 11a of the valve seat 11 is arranged at a position offset by a predetermined distance from a center of action G at which a force from the moving mechanism 13 acts on the valve element 12 to move it in a direction away from the valve seat 11, as viewed in the moving direction of the valve element 12. As a result, the center of action G of the force acting to move the valve disc 12 in a direction away from the valve seat 11 is offset from the position of the through hole 11a, which is the center of action of the suction force that draws the valve disc 12 toward the valve seat 11 due to the pressure difference of the refrigerant, so that when the valve disc 12 is moved away from the valve seat 11, the valve disc 12 tilts and a gap is formed between the valve disc 12 and the through hole 11a. As a result, the refrigerant flows into the gap formed between the valve disc 12 and the through hole 11a, reducing the pressure difference and eliminating the need to increase the force moving the valve disc 12. As a result, there is no need to increase the size of the moving mechanism 13, which prevents the electronic expansion valve 1 from becoming too large.

[0046] In this embodiment, the valve element 12 is configured to be tilted to separate from the valve seat 11. As a result, tilting the valve element 12 reliably forms a gap between the valve element 12 and the through-hole 11a, allowing the refrigerant to flow into the gap between the valve element 12 and the valve seat 11, reducing the pressure difference acting on the valve element 12 and allowing the valve element 12 to be easily separated from the valve seat 11.

[0047] Furthermore, in this embodiment, the valve seat 11 is disposed at a position offset a predetermined distance from the center of action G when viewed from the direction of movement of the valve element 12, and includes a first protrusion 11b having a through hole 11a and configured to protrude toward the valve element 12. This allows the valve element 12 and the valve seat 11 to contact each other via the first protrusion 11b, thereby reducing the contact area between the valve element 12 and the valve seat 11 compared to when the valve element 12 and the valve seat 11 contact each other over the entire opposing surfaces. Here, the force acting on the valve element 12 is calculated as the product of pressure and area. Therefore, by reducing the contact area between the valve element 12 and the valve seat 11, the suction force acting on the valve element 12 due to the pressure difference can be reduced compared to when the valve element 12 and the valve seat 11 contact each other over the entire opposing surfaces. This reduces the suction force required when the moving mechanism 13 separates the valve element 12 from the valve seat 11. Furthermore, since the valve body 12 and the valve seat 11 come into contact with each other via the first protrusion 11b, the valve body 12 and the valve seat 11 can be positioned in an unstable state, making it easier to tilt the valve body 12 when moving it away from the valve seat 11.

[0048] Furthermore, in this embodiment, the first protrusion 11b is provided at a position that does not overlap with the center of action G when viewed in the movement direction of the valve element 12. As a result, when viewed in the movement direction of the valve element 12, the surface of the first protrusion 11b where the valve element 12 and the valve seat 11 come into contact does not overlap with the center of action, so that the range in which the suction force caused by the pressure difference of the refrigerant acts on the valve element 12 can be reliably offset from the center of action G of the movement mechanism 13. As a result, the movement mechanism 13 can be prevented from being affected by the suction force caused by the pressure difference of the refrigerant.

[0049] Furthermore, in this embodiment, at least one of the valve seat 11 and the valve element 12 includes a second protrusion 11c, the first protrusion 11b and the second protrusion 11c have the same protrusion height, and the second protrusion 11c is disposed on the opposite side of the first protrusion 11b with respect to the center of action G. Thus, by providing the second protrusion 11c, the valve element 12 can be stably disposed with respect to the valve seat 11, and therefore, when the electronic expansion valve 1 is closed, the valve element 12 can be prevented from tilting and causing the refrigerant to flow to the valve seat 11.

[0050] Furthermore, in this embodiment, the valve seat 11 includes the second protrusion 11c, but the second protrusion 11c does not have a through-hole 11a. Therefore, the first protrusion 11b and the second protrusion 11c are disposed on the valve seat 11. Therefore, the positions of the first protrusion 11b and the second protrusion 11c can be easily adjusted compared to when the second protrusion 11c is provided on the valve body 12. Furthermore, when the second protrusion 11c has a through-hole, a resultant force of a suction force due to a pressure difference of the refrigerant acting on the valve body 12 at the first protrusion 11b and a suction force due to a pressure difference of the refrigerant acting on the valve body 12 at the second protrusion 11c acts on the valve body 12. Therefore, by not providing a through-hole in the second protrusion 11c, it is possible to prevent the suction force due to the pressure difference of the refrigerant from increasing. This makes it possible to prevent the movement mechanism 13 from becoming larger in size in order to increase the suction force of the movement mechanism 13.

[0051] Furthermore, in this embodiment, an annular member 14 is provided around the valve disc 12 and defines a refrigerant passage between the valve disc 12 and the outer peripheral surface 12a of the valve disc 12, and the valve disc 12 is tiltable by the gap between the inner peripheral surface of the annular member 14 and the outer peripheral surface 12a of the valve disc 12. As a result, the size of the refrigerant passage is set by the size of the gap between the inner peripheral surface of the annular member 14 and the outer peripheral surface 12a of the valve disc 12, and the amount of refrigerant can be set to a constant amount by the size of the inner diameter of the annular member 14. Furthermore, by reducing the size of the gap between the inner peripheral surface of the annular member 14 and the outer peripheral surface 12a of the valve disc 12, it is possible to prevent the valve disc 12 from tilting significantly.

[0052] Furthermore, in this embodiment, the center of action G is located at the center of gravity of the valve disc 12, and the through hole 11a is disposed at a position offset by a predetermined distance from the center of gravity of the valve disc 12 when viewed in the direction of movement of the valve disc 12. This allows the center of gravity, which serves as the center of action G at which a force acts to move the valve disc 12 in a direction away from the valve seat 11 when the valve disc 12 separates from the valve seat 11, to be offset from the position of the through hole 11a, which serves as the center of action at which a suction force due to a pressure difference in the refrigerant acts, so that when the valve disc 12 separates from the valve seat 11, the valve disc 12 tilts and a gap is formed between the valve disc 12 and the through hole 11a. As a result, refrigerant flows into the gap between the valve disc 12 and the valve seat 11, reducing the pressure difference acting on the valve disc 12 and allowing the valve disc 12 to separate from the valve seat 11 easily.

[0053] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0054] For example, in the above embodiment, the refrigeration cycle is used in a showcase, but the present invention is not limited to this. In the present invention, the refrigeration cycle may be used in an air conditioner or the like.

[0055] Furthermore, in the above embodiment, the object to be cooled is air, but the present invention is not limited to this. In the present invention, the object to be cooled may be a liquid.

[0056] Furthermore, in the above embodiment, an example was shown in which the first protrusion was provided on the valve seat, but the present invention is not limited to this. In the present invention, the first protrusion does not have to be provided on the valve seat.

[0057] Furthermore, in the above embodiment, an example in which the second protrusion is provided has been shown, but the present invention is not limited to this. In the present invention, the second protrusion does not necessarily have to be provided.

[0058] In the above embodiment, the second protrusion is provided on the valve seat, but the present invention is not limited to this. In the present invention, the second protrusion may be provided on the valve body.

[0059] In addition, in the above embodiment, an example in which one second protrusion is provided has been shown, but the present invention is not limited to this. In the present invention, two or more second protrusions may be provided. In this case, for example, three second protrusions may be provided.

[0060] In the above embodiment, the moving mechanism is disposed above the valve body, but the present invention is not limited to this. In the present invention, the moving mechanism may be disposed to the side of the valve body. [Explanation of symbols]

[0061] 1 Electronic Expansion Valve 11 Valve seat 11a Through hole 11b 1st protrusion 11c Second protrusion 12 Valve body 13a Electromagnet 13b biasing member G center of action

Claims

1. An electronic expansion valve used in a refrigeration cycle in which a refrigerant circulates, a valve seat provided with a through hole through which the refrigerant passes; a valve body that is disposed opposite the valve seat, that is configured to block the through hole by contacting the valve seat, and that allows the refrigerant to flow through the through hole by separating from the valve seat, and that is tiltable relative to the valve seat; a moving mechanism including an electromagnet that moves the valve element in a direction away from the valve seat by magnetic force, and an urging member that moves the valve element in a direction approaching the valve seat, the through hole of the valve seat is disposed at a position offset by a predetermined distance from the center of action of a force acting from the movement mechanism to move the valve body in a direction away from the valve seat, as viewed in the movement direction of the valve body; At least one of the valve seat and the valve body includes a first protrusion provided at a position corresponding to the through hole, At least one of the valve seat and the valve body includes a second protrusion provided at a position different from the first protrusion as viewed in the direction of movement of the valve body.

2. The electronic expansion valve according to claim 1 , wherein the valve element is configured to tilt away from the valve seat.

3. 3. The electronic expansion valve according to claim 1, wherein the valve seat is disposed at a position offset by a predetermined distance from the center of action as viewed in the direction of movement of the valve element, and includes the first protrusion having the through hole and configured to protrude toward the valve element.

4. The electronic expansion valve according to claim 3 , wherein the first protrusion is provided at a position that does not overlap with the center of action when viewed in the direction of movement of the valve body.

5. An electronic expansion valve as described in claim 3 or 4, wherein the first protrusion and the second protrusion have the same protrusion height, and the second protrusion is positioned on the opposite side of the first protrusion with respect to the center of action.

6. the valve seat includes the second protrusion, The electronic expansion valve according to claim 5 , wherein the second protrusion is not provided with the through-hole.

7. an annular member provided around the valve body and defining a refrigerant passage between the valve body and an outer peripheral surface of the valve body; 7. The electronic expansion valve according to claim 1, wherein the valve body is tiltable by a gap between an inner peripheral surface of the annular member and an outer peripheral surface of the valve body.

8. The center of action is located at the center of gravity of the valve body, 8. The electronic expansion valve according to claim 1, wherein the through hole is disposed at a position offset a predetermined distance from the center of gravity of the valve body when viewed in the direction of movement of the valve body.

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