Electric valve

Abstract

Provided is an electrically operated valve capable of suppressing fluid leakage when the valve is closed and realizing high-precision flow control. The electrically operated valve includes: a valve body including a valve chamber that accommodates a valve body unit and has a valve seat; a tank connected to the valve body; a rotor of an electric motor that is driven to rotate; and a switching mechanism that displaces a drive unit in the axial direction in accordance with the rotation angle of the rotor, the valve body unit having a valve shaft connected to the drive unit, and a valve body part that is movable relative to the valve shaft in the axial direction and is brought into contact with and separated from the valve seat, an elastic body is disposed on one of the valve shaft and the valve main body so as to surround the periphery of the valve seat, and a contact section that comes into contact with and separates from the elastic body is disposed on the other of the valve shaft and the valve main body.

Description

Technical Field

[0001] The present invention relates to an electric valve. Background Art

[0002] Conventionally, an electric valve is, for example, assembled in the middle of a fluid piping system and is used to open and close a fluid flow path and control the flow rate. For example, in the electric valve shown in Patent Document 1, a planetary gear reduction mechanism is used to increase the torque of a stepping motor mounted on a valve body and transmit it to a valve element, thereby achieving high-precision flow rate control and sealing performance when the valve is closed.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2023-155785

[0004] Technical Problem to be Solved by the Invention

[0005] However, in the electric valve of Patent Document 1, a structure is adopted in which a metal valve element contacts and separates from a metal valve seat to perform the opening and closing valve operation. Therefore, when the valve is closed with a foreign object sandwiched between the valve seat and the valve element, biting of the foreign object may occur, and indentations may be formed on the sealing surfaces of the valve seat or the valve element, thereby causing concern about fluid leakage when the valve is closed.

[0006] As a countermeasure, it is also a solution to make one of the valve seat and the valve element made of rubber. However, when their materials are changed to rubber, due to heat or aging, the elastic force weakens (volume decreases), etc., and the gap between the valve seat and the valve element during valve opening changes, which may affect the fluid flow rate adjustment or make the flow rate control difficult. Summary of the Invention

[0007] The present invention has been made in view of this technical problem, and an object thereof is to provide an electric valve capable of suppressing fluid leakage when the valve is closed and achieving high-precision flow rate control.

[0008] Technical Means for Solving the Technical Problem

[0009] The electric valve of the present invention has:

[0010] A valve body including a valve chamber that houses a valve element unit and has a valve seat;

[0011] A can body connected to the valve body;

[0012] A rotor of a motor that is driven to rotate; and

[0013] A conversion mechanism that displaces a drive part in the axial direction according to the rotation angle of the rotor,

[0014] The spool unit has a valve shaft and a spool portion. The valve shaft is connected to the drive portion. The spool portion can move relative to the valve shaft in the axial direction and can come into contact with and separate from the valve seat.

[0015] An elastomer is disposed around the valve seat on one of the valve shaft and the valve body, and an abutting portion that comes into contact with and separates from the elastomer is provided on the other of the valve shaft and the valve body.

[0016] Effect of the Invention

[0017] According to the present invention, an electric valve capable of suppressing fluid leakage during valve closing and achieving high-precision flow control can be provided. Description of the Drawings

[0018] Figure 1 is a longitudinal sectional view showing the valve closing state of the electric valve according to the first embodiment.

[0019] Figure 2 is a view showing the periphery of the valve seat of the electric valve in the fully closed valve region.

[0020] Figure 3 is a view showing the periphery of the valve seat of the electric valve in the boundary region.

[0021] Figure 4 is a view showing the periphery of the valve seat of the electric valve in the flow control region.

[0022] Figure 5 is a flow characteristic diagram of the electric valve according to the first embodiment.

[0023] Figure 6 is a view showing the periphery of the valve seat of the electric valve according to the second embodiment in the fully closed valve region.

[0024] Reference Signs

[0025] 1 Electric valve

[0026] 2, 2A Valve body

[0027] 3 Tank

[0028] 40 Spool unit

[0029] 41, 41A Valve shaft

[0030] 42 Spool portion

[0031] 43 Anti-disengagement member

[0032] 44 Helical spring

[0033] 45 Elastomer

[0034] 6 Reduction mechanism

[0035] 8 Support shaft

[0036] VC valve chamber

[0037] T1 First pipe

[0038] T2 Second pipe Specific implementation mode

[0039] Hereinafter, an embodiment of the electric valve of the present invention will be described with reference to the accompanying drawings. In addition, in this specification, the rotor side will be described as the upper side, and the valve core side will be described as the lower side. The strange planetary gear reduction mechanism is a form of the planetary gear reduction mechanism.

[0040] [First embodiment]

[0041] Figure 1 It is a longitudinal sectional view showing the closed valve state of the electric valve 1 according to the first embodiment of the present invention. Figures 2 - 4 It is a view enlarging the vicinity of the valve seat of the electric valve 1 according to the first embodiment. The electric valve 1 of the present embodiment is used, for example, to adjust the refrigerant flow rate in a refrigeration cycle. The axis of the electric valve 1 is set as L.

[0042] The electric valve 1 of the present embodiment is composed of the following components: a valve body 2 having a valve seat 2a formed inside the valve chamber VC; a top cylindrical tank body 3 made of metal and fixed to the valve body 2 via an annular body 31; a stepping motor formed by a stator (not shown) installed outside the tank body 3 and a rotor 57 installed inside the tank body 3; a reduction mechanism 6 that receives and transmits the torque of the rotor 57; a valve core unit 40 that contacts and separates from the valve seat 2a disposed in the valve chamber VC to control the fluid passage amount; and a screw drive member (drive portion) 22 that converts the rotational motion of the output gear of the reduction mechanism 6 into a linear motion via a screw feed mechanism (conversion mechanism) 27 to drive the valve core unit 40.

[0043] In the valve body 2, a valve port 16 communicating with the valve chamber VC is formed along the axis L, and a first pipe T1 is connected to the valve port 16 side by brazing or the like. In addition, a second pipe T2 is connected by brazing or the like so as to communicate with an opening 18 formed on the side surface of the valve chamber VC. The axis of the second pipe T2 is set as O. The axis O is orthogonal to the axis L.

[0044] In addition, a threaded bearing member 13 having an internal threaded portion 13a formed on the lower end side of the center is inserted into the upper part of the valve chamber VC of the valve body 2, and the threaded bearing member 13 is fixed to the valve body 2 by press-fitting or the like.

[0045] An axially supporting portion 81 made of resin is installed inside the upper end of the tank body 3. More specifically, the axially supporting portion 81 is formed by connecting a cylindrical portion 81a whose upper end surface abuts against the lower surface of the tank body 3 and a flange portion 81b whose outer periphery abuts against the inner periphery of the tank body 3 disposed around the cylindrical portion 81a. At the center of the axially supporting portion 81, a through hole 81c penetrating vertically is formed coaxially with the axis L. The inner diameter of the through hole 81c is substantially equal to the outer diameter of the support shaft 8.

[0046] The reduction mechanism 6 has, on the inner peripheral side of the rotor 57: a sun gear 61 formed integrally with the rotor support member 56; a fixed ring gear 62 fixed via a thin-walled cylindrical body 66 fixed to the upper part of the valve body 2 and extending upward; a planetary gear 63 disposed between the sun gear 61 and the fixed ring gear 62 and meshing with the sun gear 61 and the fixed ring gear 62 respectively; a gear carrier 64 rotatably supporting the planetary gear 63; and a bottomed cylindrical output gear member 65 having teeth meshing with the planetary gear 63 on its inner periphery, and they constitute a differential planetary gear reduction mechanism. The number of teeth of the fixed ring gear 62 is set to be different from the number of teeth of the output gear member 65.

[0047] The metal support shaft 8 penetrates the rotor support member 56 and the sun gear 61, and is held so as to be able to rotate together with the rotor support member 56 and the sun gear 61. The upper end of the support shaft 8 is fitted into the through hole 81c of the axially supporting portion 81 installed in the tank body 3, and is supported so as to be movable in the rotational direction and the direction of the axis L.

[0048] The upper part of the stepped cylindrical output shaft portion 29 formed on the upper part of the screw drive member 22 is press-fitted into the center of the bottom of the output gear member 65. The lower end of the support shaft 8 is fitted into the upper opening of the output shaft portion 29 by press-fitting, and is configured such that the output gear member 65, the support shaft 8, and the output shaft portion 29 rotate integrally.

[0049] The external thread portion 22a formed on the lower part of the screw drive member 22 is screwed into the internal thread portion 13a of the screw bearing member 13. The rotational movement of the output gear member 65 (i.e., the rotor 57) is converted into a linear movement along the axis L by a screw feed mechanism (conversion mechanism) 27 formed by the external thread portion 22a and the internal thread portion 13a.

[0050] A slit 29a is formed at the lower end of the output shaft portion 29, and a blade 22b protruding along the axis L is formed at the upper end of the screw drive member 22. The slit 29a and the blade 22b are engaged with each other in a slidable manner. Thus, the output shaft portion 29 and the screw drive member 22 are connected in a manner that enables integral rotation. If the output gear member 65 (rotor 57) rotates, the output shaft portion 29 and the screw drive member 22 rotate integrally, but can move linearly relative to each other along the axis L.

[0051] If the output gear member 65 (rotor 57) rotates, the output gear member 65 and the screw drive member 22 rotate integrally and move linearly along the axis L relative to the valve body 2. In response to the lifting of the output gear member 65, the gear carrier 64 and the planetary gear 63 placed on the bottom surface of the output gear member 65 also lift integrally with the support shaft 8.

[0052] The lower end of the spherical joint 25 formed by the ball 23 and the ball seat 24 abuts against the upper end of the hollow cylindrical spring support member 28 that is coaxially pressed into the upper end of the valve shaft 41 of the valve core unit 40. The cylindrical spring housing 19 disposed around the valve core unit 40 and the spring support member 28 is provided with a diameter-expanded portion 19a, a diameter-reduced portion 19b, and an upper flange portion 19c extending radially outward from the upper end of the diameter-expanded portion 19a. The upper flange portion 19c is engaged with the inner peripheral step portion of the valve body 2 and is fixedly held by the screw bearing member 13. The diameter-reduced portion 19b holds the outer periphery of the valve shaft 41 of the valve core unit 40 so as to be slidable.

[0053] The lower end of the compression coil spring 26 abuts against the step portion between the diameter-expanded portion 19a and the diameter-reduced portion 19b, and the upper end is engaged with the spring support member 28 and is disposed in a compressed state. Thus, a force is always applied to the valve core unit 40 in the valve-opening direction.

[0054] The linear motion of the screw drive member 22 is transmitted to the shaft-like valve core unit 40 via the spherical joint 25 and the spring support member 28. Thus, the valve core unit 40 is guided by the spring housing 19 and moves in the direction of the axis L.

[0055] The valve core unit 40 is formed by a metal valve shaft 41 and a metal valve core portion 42. The valve shaft 41 coaxially has a small-diameter portion 41a and a large-diameter portion 41b having a larger diameter than the small-diameter portion 41a. The upper end of the small-diameter portion 41a is fitted into the inner periphery of the spring support member 28 by press-fitting, and the outer periphery of the small-diameter portion 41a is fitted so as to be slidable relative to the inner periphery of the diameter-reduced portion 19b. A cylindrical recess 41c is formed at the lower end of the large-diameter portion 41b (the surface facing the valve seat 2a).

[0056] at Figures 2 - 4In it, a first inner peripheral portion 41d with a diameter-expanded portion is formed on the lower end side of the concave portion 41c, and a second inner peripheral portion 41e with a larger diameter than the first inner peripheral portion 41d. The thin-walled peripheral wall of the second inner peripheral portion 41e becomes the caulking portion 41f.

[0057] The substantially cylindrical valve core portion 42 coaxially has a first cylindrical portion 42a, a flange portion 42b, a second cylindrical portion 42c, and a tapered portion 42d. The first cylindrical portion 42a has an outer diameter smaller than the inner diameter of the concave portion 41c. The flange portion 42b has an outer diameter substantially the same as the inner diameter of the concave portion 41c. The second cylindrical portion 42c has an outer diameter larger than the outer diameter of the first cylindrical portion 42a. The tapered portion 42d has a frustum shape that tapers as it goes downward.

[0058] A spiral spring 44 is arranged between the inner periphery of the concave portion 41c and the first cylindrical portion 42a in such a manner that the upper end abuts against the bottom surface of the concave portion 41c and the lower end abuts against the upper surface of the flange portion 42b. The spiral spring 44 applies a downward force to the valve core portion 42 relative to the bottom surface of the concave portion 41c.

[0059] The thin-walled cylindrical anti-disengagement member 43 is fitted into the first inner peripheral portion 41d by press-fitting. There is a gap between the inner periphery of the anti-disengagement member 43 and the second cylindrical portion 42c of the valve core portion 42.

[0060] In a state where the upper end of the anti-disengagement member 43 abuts against the stepped portion between the first inner peripheral portion 41d and the second inner peripheral portion 41e, an annular space is formed between the outer periphery of the anti-disengagement member 43 and the inner periphery of the second inner peripheral portion 41e. An annular elastic body 45 made of rubber or resin is installed in this space. When the elastic body 45 is installed in this space, it closely adheres to the outer periphery of the anti-disengagement member 43 and the inner periphery of the second inner peripheral portion 41e due to elastic deformation. As the raw material of the elastic body 45, HNBR, PTFE, etc. can be used, but it is not limited thereto.

[0061] Before the assembly of the valve core unit 40, the caulking portion 41f of the valve shaft 41 is cylindrical. At the time of assembly, the spiral spring 44 is arranged around the first cylindrical portion 42a of the valve core portion 42. While maintaining this state, the valve core portion 42 is pressed into the concave portion 41c of the valve shaft 41, and then the anti-disengagement member 43 is installed in the first inner peripheral portion 41d by press-fitting. After that, the elastic body 45 is arranged between the outer periphery of the anti-disengagement member 43 and the inner periphery of the second inner peripheral portion 41e, and the lower end of the caulking portion 41f is plastically deformed radially inward, thereby assembling the valve core unit 40. In addition, the elastic body 45 can also be installed on the valve shaft 41 using an adhesive.

[0062] The metal valve body 2 has a prismatic valve seat 2a at the intersection of the bottom surface of the valve chamber VC and the valve port 16. The tapered portion 42d of the valve core portion 42 can be seated on the valve seat 2a over the entire circumference.

[0063] In addition, the valve body 2 has an annular protrusion (contact portion) 2b, which is arranged so as to surround the periphery of the valve seat 2a and protrude upward from the bottom surface of the valve chamber VC. The protrusion 2b has a tapered inner peripheral surface 2c that increases in diameter as it goes upward and a cylindrical outer peripheral surface 2d, and an upper end 2e whose radial width narrows can contact the elastic body 45 along the entire circumference on the radially outer side of the valve seat 2a (valve chamber VC side).

[0064] (Electric valve operation)

[0065] Figure 5 This is a flow rate characteristic diagram of the electric valve of this embodiment, which is represented by a curve diagram with the vertical axis representing the flow rate and the horizontal axis representing the valve opening (the axial position of the valve shaft 41), but the measurement of the vertical axis may be different from the actual one. Figure 5 In the flow characteristic diagram of FIG. 4 , a schematic diagram showing the relative positional relationship between the valve core portion 42 and the valve seat 2a is shown. Here, the second pipe T2 side is set as the high pressure side, and the first pipe T1 side is set as the low pressure side, but the second pipe T2 side may be set as the low pressure side, and the first pipe T1 side may be set as the high pressure side.

[0066] exist Figure 2 In the state shown, the valve shaft 41 of the valve core unit 40 is at the lowest position, and the bottom surface of the recessed portion 41c abuts against the upper end of the valve core portion 42 when the coil spring 44 is compressed. Therefore, the outer peripheral surface of the tapered portion 42d is seated on the valve seat 2a by the downward pressing force applied from the valve shaft 41, and the upper end 2e of the protruding strip portion 2b abuts against the lower surface of the elastic body 45. There is a gap between the lower surface of the flange portion 42b of the valve core portion 42 and the upper end of the anti-slip component 43.

[0067] At this time, since the lower surface of the elastic body 45 is elastically deformed appropriately, regardless of the accuracy of the parts, the upper end 2e of the protrusion 2b can be maintained in contact with the lower surface of the elastic body 45 while the outer peripheral surface of the tapered portion 42d is seated on the valve seat 2a.

[0068] When the metal valve core 42 is seated on the metal valve seat 2a, a small gap may be formed between the two, which may cause fluid leakage. According to this embodiment, even if a small gap is formed between the valve core 42 and the valve seat 2a in the closed valve state, the upper end 2e of the protrusion 2b is maintained in contact with the lower surface of the elastic body 45, so that the fluid does not flow from the valve chamber VC to the valve seat 2a side. This state is called Figure 5 The fully closed valve area A is shown.

[0069] In the fully closed valve region A, the fluid is prevented from flowing from the valve chamber VC to the valve port 16. Therefore, the movement of the fluid between the second pipe T2 and the first pipe T1 is restricted.

[0070] When the rotor 57 of the stepping motor is driven to rotate from the fully closed valve region A by supplying power to the stator, the torque of the rotor 57 is transmitted to the sun gear 61 of the speed reduction mechanism 6 via the rotor support member 56, and the torque reduced by a predetermined reduction ratio is output from the output gear member 65. The torque of the output gear member 65 is transmitted to the output shaft portion 29.

[0071] The rotational motion of the output shaft portion 29 is converted into a linear motion by the screw feed mechanism 27, whereby the output shaft portion 29 rises along the axial direction together with the valve shaft 41 of the valve core unit 40. Here, as the valve shaft 41 rises, the elastic body 45 also rises, but as the elastic body 45 rises, the abutment portion of the upper end 2e of the protrusion 2b recovers from elastic deformation. However, while the abutment state with the upper end 2e is maintained, the flow of the fluid from the valve chamber VC to the valve port 16 is prevented.

[0072] As the valve shaft 41 rises, the upper end of the valve body 42 separates from the bottom surface of the recessed portion 41 c , but the valve body 42 is pressed downward relative to the valve shaft 41 by the coil spring 44 , so the seated state of the valve body 42 and the valve seat 2 a is maintained.

[0073] When the valve shaft 41 rises to the first position P1, Figure 3 As shown, the lower surface of the elastic body 45 is separated from the upper end 2e of the protrusion 2b, and the fully closed valve area A ends. As a result, the fluid in the valve chamber VC exceeds the protrusion 2b and can move toward the valve seat 2a side, but due to the pressing force of the coil spring 44, the seated state of the valve core 42 and the valve seat 2a remains unchanged.

[0074] At this time, when there is a small gap between the valve core portion 42 and the valve seat 2a, the fluid flows from the valve chamber VC side to the valve port 16 through the gap, but the amount is very small.

[0075] Then, the valve shaft 41 rises, and after the lower surface of the flange portion 42b of the valve core portion 42 abuts against the upper end of the anti-escape component 43, the valve core portion 42 rises together with the valve shaft 41. When the valve shaft 41 rises to the second position P2, the valve core portion 42 leaves the valve seat 2a, thereby ending the boundary area B and starting the flow control area C. Figure 4 In the flow control region C shown, the fluid flows from the valve chamber VC toward the valve port 16 at a flow rate corresponding to the gap between the valve core 42 and the valve seat 2a determined by the axial position of the valve shaft 41. Therefore, movement of a predetermined flow rate of fluid between the second pipe T2 and the first pipe T1 is permitted.

[0076] By supplying power of opposite characteristics to the stator from the valve-open state, the rotor 57 rotates in the opposite direction. As a result, the valve shaft 41 descends in the opposite operation to the above, causing the valve element portion 42 to seat on the valve seat 2a. After that, by bringing the upper end 2e of the protrusion portion 2b into contact with the lower surface of the elastic body 45, it is possible to return to the fully closed valve region A.

[0077] According to the present embodiment, after the valve element portion 42 seats on the valve seat 2a, the bottom surface of the concave portion 41c is brought into contact with the upper end of the valve element portion 42. Thereby, excessive deformation of the elastic body 45 in contact with the upper end 2e of the protrusion portion 2b can be suppressed, weakening of the elastic force of the elastic body 45 can be suppressed, and the fully closed valve region A can be stably ensured for a long time. In addition, even when the elastic body 45 is deformed due to aging or the like, as long as the protrusion portion 2b is in contact and the elastic body 45 is elastically deformed, the flow of the fluid can be blocked.

[0078] In addition, when foreign matter is mixed in the fluid, there is a high possibility of biting between the upper end 2e of the protrusion portion 2b and the elastic body 45. In this case, since the elastic body 45 is elastically deformed, even if foreign matter bites between the upper end 2e and the elastic body 45, fluid leakage is blocked. Further, when the upper end 2e is separated from the elastic body 45, the foreign matter is pushed by the fluid and flows, so that the foreign matter staying at the same position is suppressed. Therefore, an electric valve 1 that can suppress fluid leakage during valve closing and achieve high-precision flow control can be provided.

[0079] [Second Embodiment]

[0080] Figure 6 The closed valve state of the electric valve showing a modified example of the second embodiment is the same figure as Figure 2 the above. In the present embodiment, the valve shaft 41A of the valve element unit 40A and the structure of the valve body 2A are different, and the other structures are the same as those of the above embodiment, so repeated descriptions are omitted.

[0081] The valve shaft 41A of the present embodiment has an annular protrusion portion 41Ag at its lower end. The inner peripheral surface of the protrusion portion 41Ag is formed by the first inner peripheral portion 41d into which the anti-disengagement member 43 is press-fitted and extends to the lower end. The outer peripheral surface of the protrusion portion 41Ag is a tapered outer peripheral surface 41Ah that tapers as it extends downward from near the lower end. The protrusion portion 41Ag also has an annular lower end 41Af.

[0082] The valve body 2A has an annular groove 2Af on the bottom surface of the valve chamber VC around the valve seat 2a. The elastic body 45 is disposed in the annular groove 2Af.

[0083] Also in the present embodiment, in the fully closed valve region A, the outer peripheral surface of the tapered portion 42d seats on the valve seat 2a, and the lower end 41Af of the protrusion portion 41Ag is in contact with the upper surface of the elastic body 45.

[0084] On the other hand, when the valve shaft 41A rises to the first position P1 (refer to Figure 5 ), the lower end 41Af of the protrusion portion 41Ag separates from the upper surface of the elastic body 45, the fully closed valve region A ends, and the boundary region B starts. In the boundary region B, the fluid in the valve chamber VC can move toward the valve seat 2a over the protrusion portion 41Ag, but due to the pressing force of the helical spring 44, the seating state of the valve element portion 42 and the valve seat 2a remains unchanged.

[0085] Furthermore, the valve shaft 41A rises, and when it rises to the second position P2 (refer to Figure 5 ), the valve element portion 42 separates from the valve seat 2a. Thus, the boundary region B ends and the flow control region C starts. In the flow control region C, the fluid flows from the valve chamber VC toward the valve port 16 using the flow rate corresponding to the gap between the valve element portion 42 and the valve seat 2a. Therefore, the movement of the fluid with a specified flow rate between the second pipe T2 and the first pipe T1 is allowed.

[0086] In addition, the present invention is not limited to the above-described embodiments. Within the scope of the present invention, any structural element of the above-described embodiments can be deformed. Further, in the above-described embodiments, any structural element can be added or omitted. For example, instead of the planetary gear reduction mechanism, a reduction mechanism formed by a pair of gears may be provided. Or, an electric valve without a reduction mechanism is also applicable to the present invention.

[0087] This specification includes the following disclosure of the invention.

[0088] (First aspect)

[0089] An electric valve, comprising:

[0090] A valve body including a valve chamber that houses a valve element unit and has a valve seat;

[0091] A can body connected to the valve body;

[0092] A rotor of an electric motor that is driven to rotate; and

[0093] A conversion mechanism that displaces a drive portion in the axial direction according to the rotation angle of the rotor,

[0094] The valve element unit has a valve shaft and a valve element portion, the valve shaft is connected to the drive portion, the valve element portion can move relative to the valve shaft in the axial direction and contact / separate from the valve seat,

[0095] An elastic body is disposed on one of the valve shaft and the valve body so as to surround the periphery of the valve seat, and a contact portion that contacts and separates from the elastic body is disposed on the other of the valve shaft and the valve body.

[0096] (Second method)

[0097] A first aspect of the electric valve, wherein:

[0098] An elastic body is disposed on the valve shaft, and an annular protrusion serving as the contact portion is formed on the valve core portion.

[0099] (Third Method)

[0100] A first aspect of the electric valve, wherein:

[0101] An elastic body is disposed on the valve body, and an annular protrusion serving as the contact portion is formed on the valve shaft.

[0102] (Fourth Method)

[0103] The electric valve according to any one of the first to third aspects, wherein:

[0104] A coil spring is provided, which urges the valve core portion in a direction toward the valve seat relative to the valve axis.

[0105] (Fifth Method)

[0106] A fourth aspect of the electric valve, wherein:

[0107] The valve core portion is arranged in a recessed portion of the valve shaft facing the valve seat side.

[0108] The recessed portion is provided with an anti-escape member that prevents the valve element from being separated from the recessed portion.

[0109] (Sixth Method)

[0110] The electric valve according to any one of the first to fifth aspects, wherein:

[0111] When the valve shaft moves in a direction away from the valve seat, the valve core portion leaves the valve seat after the elastic body leaves the abutting portion.

[0112] (Seventh Method)

[0113] The electric valve according to any one of the first to sixth aspects, wherein:

[0114] After the valve body portion leaves the valve seat, the fluid flowing through the gap between the valve body portion and the valve seat is controlled according to the axial direction position of the valve shaft.

Claims

1. An electric valve, characterized in that: have: A valve body, the valve body including a valve chamber, the valve chamber accommodating the valve core unit and having a valve seat; a tank body connected to the valve body; a rotor of the electric motor, the rotor being driven in rotation; and a conversion mechanism that displaces the driving portion in the axial direction according to the rotation angle of the rotor, The valve core unit includes a valve shaft and a valve core portion. The valve shaft is connected to the driving portion. The valve core portion can move relative to the valve shaft in an axial direction and can contact and separate from the valve seat. An elastic body is disposed on one of the valve shaft and the valve body so as to surround the periphery of the valve seat, and a contact portion that contacts and separates from the elastic body is disposed on the other of the valve shaft and the valve body.

2. The electric valve according to claim 1, characterized in that: An elastic body is disposed on the valve shaft, and an annular protrusion serving as the contact portion is formed on the valve core portion.

3. The electric valve according to claim 1, characterized in that: An elastic body is disposed on the valve body, and an annular protrusion serving as the contact portion is formed on the valve shaft.

4. The electric valve according to claim 1, characterized in that: A coil spring is provided, which urges the valve core portion in a direction toward the valve seat relative to the valve axis.

5. The electric valve according to claim 4, characterized in that: The valve core portion is arranged in a recessed portion of the valve shaft facing the valve seat side. The recessed portion is provided with an anti-escape member that prevents the valve element from being separated from the recessed portion.

6. The electric valve according to claim 1, characterized in that: When the valve shaft moves in a direction away from the valve seat, the valve core portion leaves the valve seat after the elastic body leaves the abutting portion.

7. The electric valve according to claim 6, characterized in that: After the valve body portion leaves the valve seat, the fluid flowing through the gap between the valve body portion and the valve seat is controlled according to the axial direction position of the valve shaft.

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