Electronic Expansion Valve

Abstract

To provide an electronic expansion valve capable of simplifying its device configuration while suppressing the deformation of a casing.SOLUTION: An electronic expansion valve 1 includes a casing 20 including an annular member 11 and a body part 12 abutting on an outer peripheral face 11c of the annular member 11, and a moving mechanism 15 including a yoke 15a, and a coil 15b arranged around the yoke 15a, for moving a valve element 14 with respect to a valve seat 13 with magnetic force, the annular member 11 including an inclined part 11b inclined so as to come near the valve element 14 as extending from the outer peripheral face side to the inner peripheral face side in cross sectional view along the moving direction of the valve element 14 so as to receive inner pressure from cooling medium as force to head to the center where the yoke 15a is arranged.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 configured to allow refrigerant to flow when a valve element separates from a valve seat. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known an electronic expansion valve configured to allow a refrigerant to flow when a valve element separates from a valve seat (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses an electronic expansion valve for use in a refrigeration cycle, which includes an upper body portion, a side body portion, a valve seat, and a valve element. In the electronic expansion valve of Patent Document 1, the upper body portion and the side body portion form the main body. In addition, the electronic expansion valve of Patent Document 1 is configured so that the refrigerant flows when the valve element moves away from the valve seat. [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 explicitly stated in Patent Document 1, electronic expansion valves used in refrigeration cycles have a refrigerant passing through the interior of a housing (main body), and the internal pressure of the refrigerant acts on the housing. Therefore, in the case of electronic expansion valves whose housing is made up of multiple joined components, increasing the mechanical strength is considered to prevent the housing from deforming due to the internal pressure of the refrigerant. Therefore, in order to increase the mechanical strength, it is necessary to increase the thickness of the components or to increase the joint strength by using a reinforcing member. However, increasing the thickness of the components or increasing the joint strength by using a reinforcing member complicates the device configuration, and therefore there is a demand for simplifying the device configuration.

[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 simplify the device configuration while suppressing deformation of the housing. [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 housing including an annular member forming a flow path through which the refrigerant passes and a main body abutting the outer peripheral surface of the annular member; a valve seat including a through hole through which the refrigerant passes; a valve element arranged opposite the valve seat and configured to move relative to the valve seat to switch the through hole between a closed state and an open state; a yoke arranged opposite the valve element; and a moving mechanism including a coil that generates a magnetic force in the yoke, and moving the valve element relative to the valve seat by the magnetic force. The annular member has an inner peripheral surface on which the yoke is joined, the inner peripheral surface surrounding a hole provided in the center, and the yoke includes an inclined portion that slopes toward the valve element as it moves from the outer peripheral surface side to the inner peripheral surface side of the annular member in a cross-sectional view along the movement direction of the valve element, or a first protruding portion that causes the inner peripheral surface abutting the yoke to protrude toward the valve element, so that the internal pressure of the refrigerant is received as a force toward the center where the yoke is disposed.

[0008] In one aspect of the electronic expansion valve, as described above, the annular member has a yoke bonded to its inner circumferential surface surrounding a central hole. The annular member includes a sloped portion that slopes toward the valve member as it moves from the outer circumferential surface of the annular member toward the inner circumferential surface of the annular member toward the valve member, or a first protrusion that protrudes the inner circumferential surface of the annular member that abuts the yoke toward the valve member, when viewed in a cross-sectional view along the movement direction of the valve member, so that the internal pressure of the refrigerant is received as a force toward the center where the yoke is located. This allows the sloped portion to be distributed between a force toward the center of the annular member where the yoke is located and a force from the valve member toward the yoke, which is perpendicular to the direction toward the center. This reduces the force from the valve member toward the yoke, thereby reducing the force that pushes the annular member from the valve member toward the yoke and deforms it. Furthermore, because the force toward the center presses the annular member against the yoke, there is no need to increase the bonding strength between the annular member and the yoke. This results in a simplified device configuration while suppressing deformation of the housing (annular member). Furthermore, when the first protrusion is provided, the internal pressure of the refrigerant acts on the first protrusion as a force toward the center of the annular member because the first protrusion protrudes toward the valve body. This allows the annular member to be pressed against the yoke by the force toward the center, eliminating the need to increase the bonding strength between the annular member and the yoke. As a result, deformation of the housing (annular member) can be suppressed, and the device configuration can be simplified.

[0009] In the electronic expansion valve according to the above aspect, preferably, a portion of the outer circumferential surface of the annular member that abuts against the inner circumferential surface of the main body is joined to the inner circumferential surface of the main body, and the outer circumferential surface of the annular member abuts against the inner circumferential surface of the main body from the portion joined to the inner circumferential surface of the main body toward the valve body so that internal pressure from the refrigerant acts on the outer circumferential surface of the annular member as a force directed toward the outer circumferential surface of the annular member. With this configuration, when the internal pressure of the refrigerant acts on the outer circumferential surface of the annular member, a rotational moment that suppresses deformation of the annular member acts on the annular member about the joint between the annular member and the main body, in a direction opposite to the direction that moves the annular member away from the yoke, thereby suppressing deformation of the housing (annular member) in the direction away from the yoke.

[0010] In this case, the outer circumferential surface of the annular member preferably has a second protrusion that protrudes from the portion joined to the inner circumferential surface of the main body toward the valve body. This configuration increases the area of ​​the outer circumferential surface of the annular member on which the internal pressure of the refrigerant acts by providing the second protrusion. This increases the rotational moment that suppresses deformation of the annular member, centered on the joint between the annular member and the main body. This further suppresses deformation of the housing (annular member) in a direction away from the yoke.

[0011] In the electronic expansion valve according to the above aspect, the annular member preferably includes an inclined portion, and when viewed in a cross-sectional view along the direction of movement of the valve disc, the length of the inclined portion abutting the yoke along the direction of movement of the valve disc is longer than the length of the portion of the annular member, excluding the outer periphery, that does not include the inclined portion along the direction of movement of the valve disc. This configuration allows the length of the inclined portion along the direction of movement of the valve disc to be increased, thereby increasing the contact area between the annular member and the yoke and making it difficult for the annular member to separate from the yoke. Furthermore, if a joint portion is disposed at one end of the contact portion between the yoke and the inclined portion, the distance from the end with the joint portion to the other end without the joint portion is increased, thereby increasing the rotational moment that suppresses deformation of the annular member around the other end of the contact portion between the yoke and the inclined portion as a fulcrum. As a result, the annular member can be pressed firmly against the yoke joined to the center of the annular member, thereby suppressing deformation of the housing (annular member) in a direction away from the yoke.

[0012] In this case, the inclined portion is preferably configured to incline up to the vicinity of the end of the yoke on the valve disc side. With this configuration, when a joint portion is disposed at one end of the contact portion between the yoke and the inclined portion, the distance from the end with the joint portion to the other end without the joint portion can be maximized. This reliably increases the contact area between the annular member and the yoke and further reduces the likelihood of the housing (annular member) separating from the yoke. Furthermore, since the distance from the end with the joint portion to the other end without the joint portion can be maximized, the rotational moment that suppresses deformation of the annular member with the other end of the contact portion between the yoke and the inclined portion as a fulcrum can be maximized. As a result, the annular member can be strongly pressed against the yoke joined to the center of the annular member, effectively suppressing deformation of the housing (annular member) in a direction away from the yoke. Note that "near" includes cases where the end of the yoke on the valve disc side and the end of the annular member are located at the same position or close to each other in a cross-sectional view along the movement direction of the valve disc.

[0013] In the electronic expansion valve according to the above aspect, the annular member preferably includes a first protrusion, and the length of the first protrusion along the direction of movement of the valve disc is preferably greater than the length of a portion of the annular member, excluding the outer periphery, where the first protrusion is not provided, along the direction of movement of the valve disc. This configuration allows the length of the first protrusion along the direction of movement of the valve disc to be increased, thereby increasing the contact area between the annular member and the yoke and making it difficult for the housing (annular member) to separate from the yoke. Furthermore, if a joint is provided at one end of the contact portion between the yoke and the first protrusion as viewed in the direction of movement of the valve disc, the distance from the end where the joint is provided to the other end where the joint is not provided increases, thereby increasing the rotational moment that suppresses deformation of the annular member around the other end of the contact portion between the yoke and the first protrusion as a fulcrum. As a result, the annular member can be pressed against the yoke joined to the center of the annular member, thereby suppressing deformation of the housing (annular member) in a direction away from the yoke.

[0014] In this case, the first protrusion is preferably configured to protrude to the vicinity of the end of the yoke on the valve body side. With this configuration, when a joint is disposed at one end of the contact portion between the yoke and the first protrusion, the distance from the end with the joint to the other end without the joint can be maximized. This reliably increases the contact area between the first protrusion and the yoke and further reduces the likelihood of the housing (annular member) separating from the yoke. Furthermore, since the distance from the end with the joint to the other end without the joint can be maximized, the rotational moment that suppresses deformation of the annular member around the other end of the contact portion between the yoke and the first protrusion as a fulcrum can be maximized. As a result, the annular member can be strongly pressed against the yoke joined to the center of the annular member, effectively preventing the housing (annular member) from separating from the yoke and deforming. Note that "nearby" includes cases where the end of the yoke on the valve body side and the end of the annular member are located at the same position or close to each other in a cross-sectional view along the movement direction of the valve body. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an electronic expansion valve that can suppress deformation of the housing and simplify the device configuration. [Brief explanation of the drawings]

[0016] [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] 1 is a cross-sectional view of an electronic expansion valve according to a first embodiment. [Figure 4] FIG. [Figure 5] FIG. 2 is a partially enlarged view of the annular member according to the first embodiment. [Figure 6]5 is a partially enlarged view of the annular member for explaining the moment of force acting on the joint between the inclined portion and the yoke according to the first embodiment. FIG. [Figure 7] FIG. 4 is a cross-sectional view of an electronic expansion valve according to a second embodiment. [Figure 8] FIG. 10 is a partially enlarged view of an annular member according to a second embodiment. [Figure 9] 10 is a partially enlarged view of an annular member for explaining a moment of force acting on a joint between a first protrusion and a yoke according to a second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] [First embodiment] The electronic expansion valve 1 in the first embodiment will be described taking as an example a case where it is used in a refrigeration cycle 100a.

[0018] (Cooling device configuration) As shown in Fig. 1, the refrigeration cycle 100a is configured to cool an object to be cooled by circulating a refrigerant and performing heat exchange. The refrigeration cycle 100a of the first 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).

[0019] 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.

[0020] The electronic expansion valve 1 is configured to expand a high-pressure liquid-phase refrigerant condensed by the condenser 4. In the first embodiment, the electronic expansion valve 1 is a pulse type. The detailed structure of the electronic expansion valve 1 will be described later.

[0021] 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.

[0022] The compressor 3 is configured to compress the gas phase refrigerant evaporated in the evaporator 2 to a high pressure.

[0023] The condenser 4 is configured to condense the high-pressure refrigerant discharged from the compressor 3 into a high-pressure liquid-phase refrigerant.

[0024] (Structure of an electronic expansion valve) As shown in FIG. 3 , the electronic expansion valve 1 includes a housing 20 including an annular member 11 and a main body 12, a valve seat 13, a valve element 14, and a moving mechanism 15 including a yoke 15a and a coil 15b. The electronic expansion valve 1 is configured so that refrigerant condensed in the condenser 4 is supplied into the housing 20. The moving mechanism 15 moves the valve element 14 away from the valve seat 13, thereby supplying the refrigerant to the evaporator 2. In the first embodiment, the valve element 14 moves in the vertical direction. The direction in which the valve element 14 moves is defined as the Z direction, with the valve element 14 side defined as Z1 and the valve seat 13 side defined as Z2. Among the directions perpendicular to the Z direction, the left-right direction on the paper is defined as the X direction, with the left side of the paper defined as the X1 side and the right side of the paper defined as the X2 side. The direction perpendicular to the X and Z directions is defined as the Y direction, with the front side of the paper defined as the Y1 side and the back side of the paper defined as the Y2 side.

[0025] 4, the annular member 11 has a circular ring shape with a hole 11a at its center when viewed in the movement direction (Z direction) of the valve body 14. A yoke 15a (see FIG. 3) is joined to the inner circumferential surface of the annular member 11 that surrounds the hole 11a.

[0026] 3, the annular member 11 is provided around the valve body 14. A refrigerant passage is formed between the annular member 11 and the outer peripheral surface of the valve body 14. The refrigerant is supplied to the entire interior of the housing 20 along the annular member 11.

[0027] The annular member 11 includes an inclined portion 11b. The inclined portion 11b is configured to incline toward the Z2 side so as to approach the valve element 14 as it moves from the outer peripheral surface side of the annular member 11 (the side where the outer peripheral surface 11c of the annular member 11 abuts against the inner peripheral surface of the main body 12) to the inner peripheral surface side (the side where the inner peripheral surface of the annular member 11 abuts against the outer peripheral surface of the yoke 15a) in a cross-sectional view taken along the movement direction (Z direction) of the valve element 14. The inclination angle of the inclined portion 11b is preferably 45 degrees or more. It is preferable that the proportion of the inclined portion 11b provided in the X direction of the annular member 11 is greater than the proportion of the portion of the annular member 11 where the inclined portion 11b is not provided, excluding the outer peripheral portion. While FIG. 3 is a cross-sectional view taken along the X direction, the annular member 11 has the same structure as that shown in FIG. 3 when viewed along the Y direction.

[0028] As shown in FIG. 5, the annular member 11 has a first joint portion 16 formed on a portion of the outer peripheral surface 11c of the annular member 11 that abuts against the inner peripheral surface of the main body portion 12 (the surface facing the yoke 15a). The first joint portion 16 is formed on the inner peripheral surface and the upper surface of the main body portion 12. The annular member 11 has a second joint portion 17 formed on the Z1-side surface of the annular member 11 that abuts against the yoke 15a. The joining method is, for example, laser welding. Note that FIG. 5 is a cross-sectional view taken along the X direction, but the annular member 11 has the same structure as that shown in FIG. 5 when viewed along the Y direction.

[0029] The outer periphery of the annular member 11 is provided with leg portions 11d that protrude from a portion joined to the inner periphery of the main body portion 12 toward the valve body 14 side (Z2 side). The annular member 11 is configured such that the outer periphery 11c of the annular member 11 abuts against the inner periphery of the main body portion 12 by the leg portions 11d from a portion joined to the inner periphery of the main body portion 12 toward the valve body 14 side (Z2 side) so as to receive the internal pressure from the refrigerant as a force directed in the outer periphery direction (toward the main body portion 12). The leg portions 11d are an example of a "second protrusion" recited in the claims.

[0030] When viewed in cross section along the movement direction (Z direction) of the valve body 14, the annular member 11 is configured so that the length L1 along the movement direction (Z direction) of the valve body 14 of the inclined portion 11b abutting the yoke 15a is greater than the length L2 along the movement direction (Z direction) of the valve body 14 of the portion of the annular member 11 where the inclined portion 11b is not provided, excluding the outer periphery thereof.

[0031] 3, the main body 12 has a valve seat 13 and a valve element 14 disposed therein. The main body 12 has a cylindrical shape that opens to the Z1 side, and an annular member 11 is attached to the Z1 side. The housing 20 is formed by attaching the annular member 11 to the main body 12.

[0032] The valve seat 13 is provided with a through hole 13a through which the refrigerant passes. The valve seat 13 is made of stainless steel. The valve seat 13 is made of non-magnetic austenitic stainless steel. The valve seat 13 has a circular shape when viewed in the movement direction (Z direction) of the valve disc 14.

[0033] The valve element 14 faces the movement mechanism 15. The valve element 14 moves in the vertical direction (Z direction) by the movement mechanism 15. The valve element 14 also faces the valve seat 13 in the vertical direction (Z direction). The valve element 14 is made of ferritic stainless steel, which is easily magnetized. The valve element 14 has a circular shape when viewed in the movement direction (Z direction) of the valve element 14.

[0034] The movement mechanism 15 includes a yoke (iron core) 15a and a coil 15b. The coil 15b generates a magnetic force in the yoke 15a. When current is applied to the coil 15b, the movement mechanism 15 generates a magnetic force, attracts the valve element 14, and separates the valve element 14 from the valve seat 13, thereby opening the electronic expansion valve 1. When the coil 15b is not energized, the valve element 14 abuts against the valve seat 13, substantially sealing the through-hole 13a, thereby closing the electronic expansion valve 1. The yoke 15a has a stepped portion formed on its Z2-side surface that abuts against the Z1-side surface and the inner circumferential surface of the top surface of the annular member 11, which is closer to the center of the top surface.

[0035] The internal pressure acting on the annular member 11 will be described with reference to Fig. 5. Fig. 5 is an enlarged view of a portion of the yoke 15a on the X1 side from the central axis α.

[0036] 5, when the inclined portion 11b is provided, the internal pressure of the refrigerant acts perpendicularly to the Z2 side surface of the inclined portion 11b, as indicated by the solid arrow. This internal pressure can be dispersed into a force in the Z1 direction and a force in the X1 direction, as indicated by the dashed arrow.

[0037] The force in the Z1 direction is reduced by the inclined portion 11b, and accordingly the force that pushes the Z2 side surface of the annular member 11 toward the outer periphery (R1 direction) is reduced, thereby suppressing deformation of the annular member 11. Furthermore, since the force that joins the annular member 11 to the yoke 15a is a force in the X1 direction, when a force in the X1 direction is generated by internal pressure, the force that joins the annular member 11 to the yoke 15a can be increased.

[0038] The outer periphery of the annular member 11 is provided with leg portions 11d that protrude from a first joint portion 16 joined to the inner periphery of the main body portion 12 toward the valve body 14. This causes a moment (a rotational moment that suppresses deformation of the annular member 11) to act on the leg portions 11d, rotating them toward the center of the annular member 11 (in the R2 direction) around the first joint portion 16 as a fulcrum. This causes the annular member 11 to be pressed against the yoke 15a and come into contact with it. The internal pressure acting on the leg portions 11d is the same as, but in the opposite direction to, the internal pressure acting on the leg portions 11d, which are positioned symmetrically with respect to the central axis α of the yoke 15a. Therefore, the forces are canceled out, and the internal pressure acting on the leg portions 11d toward the outer periphery does not deform the annular member 11.

[0039] As shown in FIG. 6, a moment (a rotational moment that suppresses deformation of the annular member 11) acts on the portion (second joint portion 17) where the yoke 15a and the inclined portion 11b contact each other, as indicated by the arrow, rotating the inclined portion 11b toward the yoke 15a, with the end of the inclined portion 11b on the valve body 14 side (Z2 side) as a fulcrum P. This moment prevents the annular member 11 from being deformed by separating from the yoke 15a. Because the moment increases as the length L1 of the contact point between the yoke 15a and the annular member 11 increases, it is preferable that the inclined portion 11b be configured to incline up to the vicinity of the end of the yoke 15a on the valve body 14 side. Note that while FIG. 6 is a cross-sectional view taken along the X direction, the annular member 11 has the same structure as that shown in FIG. 6 when viewed along the Y direction.

[0040] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0041] In the first 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 housing 20 including an annular member 11 that forms a flow path through which the refrigerant passes and a main body 12 that abuts against an outer circumferential surface 11c of the annular member 11; a valve seat 13 that includes a through hole 13a that allows the refrigerant to pass; a valve element 14 that is arranged to face the valve seat 13 and is configured to move relative to the valve seat 13 so as to switch the through hole 13a between a closed state and an open state; and a yoke 16 that is arranged to face the valve element 14. The valve seat 13 includes a moving mechanism 15 including a yoke 15a and a coil 15b that generates a magnetic force in the yoke 15a, and the magnetic force moves the valve element 14 relative to the valve seat 13. The annular member 11 has the yoke 15a joined to its inner circumferential surface surrounding a central hole 11a. The annular member 11 includes an inclined portion 11b that slopes toward the valve element 14 from the outer circumferential surface of the annular member 11 toward the inner circumferential surface thereof in a cross-sectional view taken along the movement direction of the valve element 14, so that the internal pressure caused by the refrigerant is received as a force toward the center where the yoke 15a is located. By providing the inclined portion 11b, the internal pressure caused by the refrigerant can be divided into an outward force and a force toward the center, thereby reducing the outward force. This allows the direction of the internal pressure acting on the inclined portion 11b to be dispersed into a force toward the center of the annular member 11 where the yoke 15a is located, and a force from the valve element 14 side toward the yoke 15a, which is perpendicular to the direction toward the center. Therefore, the force directed from the valve body 14 side to the yoke 15a side can be reduced, and the force that pushes the annular member 11 from the valve body 14 side to the yoke 15a side and deforms it can be reduced. Also, because the annular member 11 can be pressed against the yoke 15a by the force directed toward the center, there is no need to increase the bonding strength between the annular member 11 and the yoke 15a. As a result, the device configuration can be simplified while suppressing deformation of the housing 20 (annular member 11).

[0042] Furthermore, in the first embodiment, a portion of the outer circumferential surface 11c of the annular member 11 that abuts against the main body 12 is joined to the inner circumferential surface of the main body 12, and the outer circumferential surface 11c of the annular member 11 abuts against the main body 12 from the portion joined to the inner circumferential surface of the main body 12 toward the valve body so that the annular member 11 receives internal pressure from the refrigerant as a force directed toward the outer periphery of the annular member 11. As a result, when the internal pressure of the refrigerant acts on the outer circumferential surface 11c of the annular member 11, a rotational moment that suppresses deformation of the annular member 11 acts on the annular member 11 around the joint between the annular member 11 and the main body 12, in the direction opposite to the direction that moves the annular member 11 away from the yoke 15a, and therefore deformation of the housing 20 (annular member 11) in the direction away from the yoke 15a can be suppressed.

[0043] Furthermore, in the first embodiment, the outer periphery of the annular member 11 is provided with leg portions 11d that protrude from the portion joined to the inner periphery of the main body 12 toward the valve body 14. Providing the leg portions 11d increases the area of ​​the outer periphery 11c of the annular member 11 on which the internal pressure of the refrigerant acts, thereby increasing the rotational moment that suppresses deformation of the annular member 11 around the joint between the annular member 11 and the main body 12. As a result, deformation of the housing 20 (annular member 11) in a direction away from the yoke 15a can be further suppressed.

[0044] In the first embodiment, the annular member 11 includes an inclined portion 11b. When viewed in a cross-sectional view along the movement direction of the valve disc 14, the length of the inclined portion 11b that abuts against the yoke 15a along the movement direction of the valve disc 14 is longer than the length of the portion of the annular member 11 that does not include the inclined portion 11b, excluding the outer circumferential portion of the annular member 11, along the movement direction of the valve disc 14. This increases the length of the inclined portion 11b along the movement direction of the valve disc 14, thereby increasing the contact area between the annular member 11 and the yoke 15a and making it difficult for the annular member 11 to separate from the yoke 15a. Furthermore, when a joint portion is disposed at one end of the contact portion between the yoke 15a and the inclined portion 11b, the distance from the end where the joint portion is provided to the other end where the joint portion is not provided increases, thereby increasing the rotational moment that suppresses deformation of the annular member 11, with the other end of the contact portion between the yoke 15a and the inclined portion 11b as a fulcrum. As a result, the annular member 11 can be pressed against the yoke 15a joined to the center of the annular member 11, and deformation of the housing 20 (annular member 11) in a direction away from the yoke 15a can be suppressed.

[0045] In the first embodiment, the inclined portion 11b is configured to incline up to the vicinity of the end of the yoke 15a on the valve body 14 side. This allows the distance from the end with the inclined portion 11b at which the yoke 15a and the inclined portion 11b abut to approach its maximum value when a joint is disposed at one end of the abutment between the yoke 15a and the inclined portion 11b to the other end without the joint to approach its maximum value. This reliably increases the contact area between the annular member 11 and the yoke 15a and makes it even more difficult for the housing 20 (annular member 11) to separate from the yoke 15a. Furthermore, the distance from the end with the inclined portion to the other end without the joint to approach its maximum value allows the rotational moment that suppresses deformation of the annular member 11, with the other end of the abutment between the yoke 15a and the inclined portion 11b as a fulcrum, to approach its maximum value. As a result, the annular member 11 can be strongly pressed against the yoke 15a joined to the center of the annular member 11, effectively suppressing deformation of the housing 20 (annular member 11) in a direction away from the yoke 15a.

[0046] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to Figs. 1, 2, and 7 to 9. In this second embodiment, an example will be described in which a first protrusion 11e is provided on an annular member 111, unlike the annular member 11 of the first embodiment. Note that the same components as those in the first embodiment will be denoted by the same reference numerals and will not be described again. Note that Figs. 8 and 9 are enlarged views of a portion of the yoke 15a on the X1 side from the central axis α.

[0047] 7, annular member 111 includes a first protrusion 11e that protrudes the inner circumferential surface that contacts yoke 15a toward valve body 14 so that the internal pressure of the refrigerant is received as a force toward the center where yoke 15a is disposed. Note that while FIG. 7 is a cross-sectional view taken along the X direction, annular member 111 has the same structure as that shown in FIG. 7 when viewed along the Y direction.

[0048] As shown in Fig. 8, the length L3 of the first protrusion 11e that abuts against the yoke 15a along the movement direction (Z direction) of the valve element 14 (see Fig. 7) is configured to be greater than the length L4 of the portion of the annular member 111, excluding the outer periphery, where the first protrusion 11e is not provided, along the movement direction (Z direction) of the valve element 14. Furthermore, it is preferable that the first protrusion 11e be configured to protrude to the vicinity of the end of the yoke 15a on the valve element 14 side (Z2 side). Note that Fig. 8 is a cross-sectional view taken along the X direction, but the annular member 111 has the same structure as that shown in Fig. 8 when viewed along the Y direction.

[0049] 8, when the first protrusion 11e is provided, internal pressure of the refrigerant acts on the first protrusion 11e toward the X1 side, as indicated by the solid arrow. Because the force joining the annular member 111 to the yoke 15a is a force in the X1 direction, when a force in the X1 direction is generated by the internal pressure, the force joining the annular member 111 to the yoke 15a can be increased.

[0050] As shown in FIG. 9, a moment is generated at the portion (second joint portion 17) where the yoke 15a and the first protrusion 11e contact each other, which rotates the first protrusion 11e toward the yoke 15a, as indicated by the arrow, with the end of the first protrusion 11e on the valve body 14 side (Z2 side) as a fulcrum P. This moment prevents the annular member 111 from being separated from the yoke 15a and deforming. Because the moment increases as the length L3 of the contact point between the yoke 15a and the annular member 111 increases, it is preferable that the first protrusion 11e protrude to the vicinity of the end of the yoke 15a on the valve body 14 side (Z2 side). Note that while FIG. 9 is a cross-sectional view taken along the X direction, the annular member 111 has the same structure as that shown in FIG. 9 when viewed along the Y direction.

[0051] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0052] In the second embodiment, as described above, the electronic expansion valve 1 is used in a refrigeration cycle 100a in which a refrigerant circulates, and includes a housing 20 including an annular member 111 that forms a flow path through which the refrigerant passes and a main body 12 that abuts against an outer circumferential surface 11c of the annular member 111; a valve seat 13 that includes a through hole 13a that allows the refrigerant to pass; a valve element 14 that is disposed opposite the valve seat 13 and is configured to move relative to the valve seat 13 so as to switch the through hole 13a between a closed state and an open state; and a valve element 14 that is disposed opposite the valve seat 13 and is configured to move relative to the valve seat 13 so as to switch the through hole 13a between a closed state and an open state. The valve seat 13 includes a yoke 15a disposed opposite the valve seat 13, a coil 15b that generates a magnetic force in the yoke 15a, and a moving mechanism 15 that moves the valve element 14 relative to the valve seat 13 using the magnetic force. The annular member 111 has an inner circumferential surface surrounding a central hole 11a to which the yoke 15a is joined, and a first protrusion 11e that protrudes from the inner circumferential surface that abuts the yoke 15a toward the valve element 14 so as to receive the internal pressure of the refrigerant as a force toward the center where the yoke 15a is disposed. Since the first protrusion 11e protrudes toward the valve element 14, the internal pressure of the refrigerant acts on the first protrusion 11e as a force toward the center of the annular member 11. This allows the annular member 11 to be pressed against the yoke 15a by the force toward the center, eliminating the need for increased bonding strength between the annular member 11 and the yoke 15a. This simplifies the device configuration while suppressing deformation of the housing 20 (annular member 111).

[0053] Furthermore, in the second embodiment, as described above, the annular member 111 includes the first protrusion 11e, and is configured so that, in a cross-sectional view along the movement direction of the valve element 14, the length L3 of the first protrusion 11e that abuts against the yoke 15a along the movement direction of the valve element 14 is greater than the length L4 of the portion of the annular member 111 along the movement direction of the valve element 14 where the first protrusion 11e is not provided, excluding the outer periphery thereof. This makes it possible to increase the length L3 of the first protrusion 11e along the movement direction of the valve element 14, thereby increasing the contact area between the annular member 111 and the yoke 15a, and therefore making it difficult for the housing 20 (annular member 111) to separate from the yoke 15a. Furthermore, when a joint portion is disposed at one end of the contact portion between yoke 15a and first protrusion 11e as viewed in the movement direction of the valve disc, the distance from the one end where the joint portion is provided to the other end where the joint portion is not provided increases, thereby increasing the rotational moment that acts on the other end of the contact portion between yoke 15a and first protrusion 11e as a fulcrum and suppresses deformation of annular member 111. As a result, annular member 111 can be pressed against yoke 15a joined to the center of annular member 111, thereby suppressing deformation of housing 20 (annular member 111) in a direction away from yoke 15a.

[0054] Furthermore, in the second embodiment, as described above, the first protrusion 11e is configured to protrude to the vicinity of the end of the yoke 15a on the valve body 14 side. This allows the distance from the end where the joint is provided to the other end where no joint is provided to approach its maximum value when a joint is disposed at one end of the contact portion between the yoke 15a and the first protrusion 11e. This reliably increases the contact area between the first protrusion 11e and the yoke 15a and further reduces the likelihood of the housing 20 (annular member 111) separating from the yoke 15a. Furthermore, since the distance from the end where the joint is provided to the other end where no joint is provided can be approximated to its maximum value, the rotational moment that suppresses deformation of the annular member 111, with the other end of the contact portion between the yoke 15a and the first protrusion 11e as a fulcrum, can be approximated to its maximum value. As a result, the annular member 111 can be strongly pressed against the yoke 15a joined to its center, effectively suppressing deformation of the housing 20 (annular member 111) in a direction away from the yoke 15a.

[0055] [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.

[0056] For example, in the first and second embodiments, 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.

[0057] Furthermore, in the first and second embodiments, 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 liquid.

[0058] Furthermore, in the first and second embodiments, examples have been shown in which legs are provided on the annular member, but the present invention is not limited to this. In the present invention, the annular member does not necessarily have to be provided with legs.

[0059] In addition, in the first and second embodiments, examples have been shown in which the annular member and the housing are joined, but the present invention is not limited to this. In the present invention, the annular member and the housing do not need to be joined as long as they are in contact with each other.

[0060] In addition, in the first and second embodiments, the annular member and the yoke are joined together, but the present invention is not limited to this. In the present invention, the annular member and the yoke do not need to be joined together as long as they are in contact with each other. [Explanation of symbols]

[0061] 1 Electronic Expansion Valve 11, 111 Annular member 11a Hole 11b Inclined section 11c Outer surface 11d Leg (second protrusion) 11e 1st protrusion 12 Main body 13 Valve seat 14 Valve body 15 Moving mechanism 15a York 15b coil 20 Case 100a refrigeration cycle

Claims

1. An electronic expansion valve used in a refrigeration cycle in which a refrigerant circulates, a housing including an annular member that forms a flow path through which a refrigerant passes, and a main body that abuts on an outer circumferential surface of the annular member; a valve seat including a through hole for passing a refrigerant; a valve body disposed opposite the valve seat and configured to move relative to the valve seat to switch the through hole between a closed state and an open state; a moving mechanism including a yoke arranged to face the valve body and a coil that generates a magnetic force in the yoke, and that moves the valve body relative to the valve seat by the magnetic force; the annular member has an inner circumferential surface surrounding a hole provided in the center, to which the yoke is joined, and the annular member includes an inclined portion that inclines toward the valve body from the outer circumferential surface side of the annular member toward the inner circumferential surface side when viewed in a cross section along the movement direction of the valve body, or a first protruding portion that causes the inner circumferential surface abutting against the yoke to protrude toward the valve body, so that the annular member receives internal pressure due to the refrigerant as a force toward the center where the yoke is disposed.

2. 2. The electronic expansion valve according to claim 1, wherein a portion of the outer circumferential surface of the annular member that abuts on the main body portion is joined to an inner circumferential surface of the main body portion, and the outer circumferential surface of the annular member abuts on the main body portion from the portion joined to the inner circumferential surface of the main body portion toward the valve element so that the annular member receives internal pressure from the refrigerant as a force directed toward the outer circumferential direction of the annular member.

3. 3. The electronic expansion valve according to claim 2, wherein the outer circumferential portion of the annular member is provided with a second protrusion that protrudes from a portion joined to the inner circumferential surface of the main body toward the valve body.

4. The electronic expansion valve according to any one of claims 1 to 3, wherein the annular member includes the inclined portion, and is configured such that, in a cross-sectional view taken along the movement direction of the valve disc, the length of the inclined portion that abuts against the yoke along the movement direction of the valve disc is greater than the length of a portion of the annular member, excluding an outer circumferential portion, that does not include the inclined portion, along the movement direction of the valve disc.

5. The electronic expansion valve according to claim 4 , wherein the inclined portion is configured to incline up to a vicinity of the end of the yoke on the valve body side.

6. The electronic expansion valve according to any one of claims 1 to 3, wherein the annular member includes the first protrusion, and is configured such that, in a cross-sectional view along the movement direction of the valve body, a length along the movement direction of the valve body of the first protrusion that abuts against the yoke is greater than a length along the movement direction of the valve body of a portion of the annular member that is not provided with the first protrusion, excluding an outer circumferential portion.

7. The electronic expansion valve according to claim 6 , wherein the first protrusion is configured to protrude to a vicinity of an end of the yoke on the valve body side.

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