Motorized valve

Abstract

This motorized valve comprises: a cylindrical can; a cylindrical rotor disposed outside the can; a valve body that moves in accordance with rotation of the rotor; and a stator disposed inside the can, the stator having a plurality of plate-shaped pole teeth each having a flat opposing surface facing an inner wall surface of the can, one or more of the pole teeth being provided with a protrusion that partially projects from the opposing surface toward the inner wall surface of the can more than the surrounding area.

Description

Electric valve

[0001] The present disclosure relates to motorized valves.

[0002] Conventionally, an electric valve is known that includes a valve body, a can, a rotor, and a stator, as disclosed in Japanese Patent Application Laid-Open No. 2022-83453. The rotor and stator form a motor. The can is cylindrical and is joined to the valve body. The rotor is disposed inside the can. The stator is cylindrical and is disposed coaxially outside the can. The electric valve of Japanese Patent Application Laid-Open No. 2022-83453 is an outer motor type.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-83453

[0004] When the stator has multiple pole teeth, the pole teeth are usually flat and plate-shaped. When the stator is disposed outside the can, as in JP 2022-83453 A, it is relatively easy to bring the inner surfaces of the flat, plate-shaped pole teeth into contact with the outer wall surface of the cylindrical can, even if the outer wall surface of the can is curved.

[0005] However, in JP 2022-83453 A, the outer diameter of the motor-operated valve is likely to be large due to the stator located outside the can, which increases the overall space required for arranging the motor-operated valve, leaving room for improvement in terms of making the device more compact.

[0006] To make the device more compact, it is possible to place the stator inside the can, in other words, to realize an inner motor type motor-operated valve. However, when the stator is placed inside the can, the width of the gap in the circumferential center between the curved inner wall surface of the cylindrical can and the outer surface of the flat, plate-like pole teeth facing this inner wall surface becomes larger than when the stator is placed outside the can. For this reason, simply placing the stator inside the can in an inner motor type motor-operated valve raises concerns about motor torque loss due to the gap.

[0007] In view of the above, the present disclosure provides an electric valve that can reduce torque loss while making the device more compact.

[0008] The electric valve of the first aspect comprises a cylindrical can, a cylindrical rotor arranged outside the can, a valve body that moves in accordance with the rotation of the rotor, and a stator arranged inside the can, which has a plurality of plate-shaped pole teeth with flat opposing surfaces that face the inner wall surface of the can, and one or more of the pole teeth are provided with a protrusion that protrudes partially from the opposing surface toward the inner wall surface of the can beyond its surroundings.

[0009] In the motor-operated valve according to the first aspect, even if the stator is disposed inside the can, the protrusions allow the width of the gap between the stator and the can to be made smaller than in the case of pole teeth whose opposing surfaces are generally flat, for example. As a result, torque loss can be suppressed while the device is made more compact.

[0010] In a second aspect, in the motor-operated valve according to the first aspect, a portion of the protrusion that faces the inner wall surface of the can is curved.

[0011] In the second aspect, even if the protrusion comes into contact with the inner wall surface of the can, the can or the pole teeth are unlikely to be damaged.

[0012] In a third aspect, in the motor-operated valve according to the first or second aspect, the protrusion is in contact with the inner wall surface of the can.

[0013] In the third aspect, the protrusion comes into contact with the inner wall surface of the can, thereby enhancing the effect of suppressing torque loss compared to when a gap is formed between the stator and the can without the protrusion being formed.

[0014] In a fourth aspect, in the motor-operated valve according to any one of the first to third aspects, when the opposing surfaces are viewed from the front toward the central axis, the pole teeth are symmetrical with respect to a center line parallel to the central axis.

[0015] In the fourth aspect, the torque loss is more effectively suppressed than in the case where the pole teeth are asymmetric with respect to a center line parallel to the center axis, for example.

[0016] According to the present disclosure, it is possible to provide a motor-operated valve that can reduce torque loss while making the device more compact.

[0017] FIG. 1 is a cross-sectional view illustrating a motor-operated valve according to an embodiment of the present disclosure, cut by a plane including the central axis, which is the rotation axis. FIG. 2 is a perspective view illustrating a stator of the motor-operated valve according to the embodiment. FIG. 3 is a cross-sectional view illustrating the pole teeth of the stator of the motor-operated valve according to the embodiment, taken along line 3-3 in FIG. 1. FIG. 4 is a cross-sectional view illustrating an enlarged view of part A in FIG. 3. FIG. 5 is a front view illustrating the pole teeth of the stator of the motor-operated valve according to the embodiment, viewing the opposing surfaces of the pole teeth from the front. FIG. 6 is a cross-sectional view illustrating an enlarged view of the pole teeth of the stator of a motor-operated valve according to a comparative example, taken at a position corresponding to part A in FIG. 3 of this embodiment. FIG. 7 is a cross-sectional view illustrating the pole teeth of the stator of a motor-operated valve according to a modified embodiment, taken at a position corresponding to part A in FIG. 3 of this embodiment.

[0018] This embodiment will be described below. In the following description of the drawings, identical or similar parts are designated by the same or similar reference numerals. However, the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each device or component, etc. may differ from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. Furthermore, there may be parts with different dimensional relationships and ratios between the drawings. Furthermore, unless otherwise specified in the specification, the number of each component element of the present disclosure is not limited to one, and multiple elements may be present.

[0019] <Configuration of Motor-Operated Valve> A motor-operated valve 1 according to this embodiment of the present disclosure will be described below with reference to Figures 1 to 7. The motor-operated valve 1 according to this embodiment is used, for example, to control the flow rate of a fluid in an automotive air conditioner. The fluid is, for example, a high-pressure refrigerant.

[0020] As shown in FIG. 1, the motor-operated valve 1 according to this embodiment includes a valve body 10, a valve element 20, a rotor case 30, a bearing 35, a rotor 40, a drive shaft 50, and a can 60 serving as an inner case.

[0021] (Valve Body) The valve body 10 has a body member 11, a sleeve 18, and a valve element support plate 19. The body member 11 is cylindrical. The body member 11 is made of a metal such as an aluminum alloy. The outer shape of the cross section of the upper part 11A of the body member 11 in FIG. 1 is hexagonal. The "cross section" is a cross section perpendicular to the central axis L. The body member 11 has a valve chamber 12, a valve port 13, a valve seat 14, a first connecting passage 15, a second connecting passage 16, and a mounting hole 17.

[0022] The valve port 13 is connected to the valve chamber 12. The valve port 13 is surrounded by a valve seat 14 in the valve chamber 12. The first connecting passage 15 has a cross shape extending from the valve chamber 12 in the left-right direction in Figure 1 and in the front-rear direction perpendicular to the plane of the paper in Figure 1. The second connecting passage 16 extends from the valve port 13 downward in Figure 1.

[0023] The mounting hole 17 is located so as to open to the upper surface 11C of the main body member 11 in FIG. 1 . The mounting hole 17 is connected to the valve chamber 12. The main body member 11 has a retaining surface 17A, which is an annular flat surface facing upward in FIG. 1 . The retaining surface 17A is located at the connection point between the mounting hole 17 and the valve chamber 12. The main body member 11 has a male thread 11S and a female thread 11T. The male thread 11S is located on the outer peripheral surface of the lower portion 11B of the main body member 11 in FIG. 1 . The female thread 11T is located on the inner peripheral surface of the mounting hole 17. The main body member 11 also has annular grooves 11D and 11E. The upper annular groove 11D in FIG. 1 is located above the male thread 11S on the outer peripheral surface of the lower portion 11B of the main body member 11. The lower annular groove 11E in FIG. 1 is located below the first connecting passage 15 on the outer peripheral surface of the lower portion 11B of the main body member 11. O-rings (not shown) are disposed in the annular grooves 11D and 11E.

[0024] The sleeve 18 is made of synthetic resin or metal and has a cylindrical shape. The sleeve 18 integrally includes a small diameter portion 18A, a large diameter portion 18B, and a flange portion 18C.

[0025] The small diameter portion 18A and the large diameter portion 18B have a cylindrical shape. The inner diameter of the large diameter portion 18B is larger than the outer diameter of the small diameter portion 18A. The lower end of the large diameter portion 18B in FIG. 1 is coaxially connected to the upper end of the small diameter portion 18A. The flange portion 18C has an annular plate shape. The inner peripheral edge of the flange portion 18C is connected to the upper end of the large diameter portion 18B. The small diameter portion 18A and the large diameter portion 18B are disposed in the valve chamber 12. The flange portion 18C contacts the retaining surface 17A of the main body member 11.

[0026] The valve disc support plate 19 is made of synthetic resin or metal. The valve disc support plate 19 has an annular disc shape. The outer peripheral edge of the valve disc support plate 19 is circular and the inner peripheral edge is square. The valve disc support plate 19 is disposed in the mounting hole 17. The lower surface of the valve disc support plate 19 in FIG. 1 is in contact with the flange portion 18C of the sleeve 18.

[0027] (Valve body) The valve body 20 is made of synthetic resin or metal. The valve body 20 integrally includes a shaft portion 21 and a valve portion 22. The valve body 20 moves in response to the rotation of the rotor 40.

[0028] The shaft portion 21 has an overall columnar shape. The upper portion 21A of the shaft portion 21 in FIG. 1 has a rectangular columnar shape. The outer shape of the cross section of the upper portion 21A in FIG. 1 is the same square as the inner peripheral edge of the valve body support plate 19. The lower portion 21B of the shaft portion 21 in FIG. 1 has a cylindrical shape. The outer diameter of the lower portion 21B in FIG. 1 is the same as the inner diameter of the small diameter portion 18A of the sleeve 18. The shaft portion 21 has a threaded hole 21C and a female thread 21T. The threaded hole 21C is located on the upper end surface of the shaft portion 21. The female thread 21T is located on the inner peripheral surface of the threaded hole 21C.

[0029] An upper portion 21A of the shaft portion 21 in Fig. 1 is disposed inside the valve element support plate 19. A lower portion 21B of the shaft portion 21 in Fig. 1 is disposed inside the small diameter portion 18A of the sleeve 18. The valve element 20 is supported by the sleeve 18 and the valve element support plate 19 so as to be movable in the vertical direction, i.e., along the direction of the central axis L. Rotation of the valve element 20 around the central axis L is stopped by the valve element support plate 19. The shape of the upper portion 21A of the shaft portion 21 in Fig. 1 and the shape of the inner peripheral edge of the valve element support plate 19 may be any shape that stops rotation of the valve element 20 around the central axis L.

[0030] The valve portion 22 has a truncated cone shape whose diameter decreases from the top to the bottom in Fig. 1. The valve portion 22 is coaxially connected to the lower end of the shaft portion 21. The valve portion 22 is disposed in the valve chamber 12 and the valve port 13. The valve portion 22 faces the valve port 13 and the valve seat 14 in the up-down direction in Fig. 1. When the valve portion 22 comes into contact with the valve seat 14, the valve port 13 closes. When the valve portion 22 moves away from the valve seat 14, the valve port 13 opens, and as a result, a throttled flow path is formed between the valve portion 22 and the valve port 13.

[0031] (Rotor Case) The rotor case 30 is made of a metal such as non-magnetic stainless steel. In this specification, "non-magnetic" refers to the property of a material not being magnetized even when placed in a magnetic field. "Non-magnetic" also includes the property of not being substantially magnetized. The rotor case 30 may be made of a synthetic resin. The rotor case 30 is cylindrical overall. The rotor case 30 integrally includes a first portion 31, a second portion 32, and a connecting portion 33.

[0032] The first portion 31 has a cylindrical shape. The first portion 31 has a male thread 31S. The male thread 31S is located on the lower portion of the outer circumferential surface of the first portion 31 in FIG. 1 . The first portion 31 is located in the mounting hole 17 of the main body member 11, and the male thread 31S of the first portion 31 is threadedly engaged with the female thread 11T of the main body member 11. The first portion 31 is attached to the main body member 11 via a threaded structure. An O-ring 39 seals the space between the main body member 11 and the first portion 31 in the mounting hole 17. The flange portion 18C of the sleeve 18 and the valve body support plate 19 are held between the lower end of the first portion 31 in FIG. 1 and the holding surface 17A of the main body member 11. The first portion 31 has a bearing mounting surface 31A, which is an annular flat surface facing upward in FIG. 1 . The bearing mounting surface 31A is located on the inner circumferential surface of the first portion 31.

[0033] The second portion 32 has a cylindrical shape. The inner diameter of the second portion 32 is larger than the outer diameter of the first portion 31. The connecting portion 33 has an annular flat plate shape. The inner peripheral edge of the connecting portion 33 in FIG. 1 is connected to the upper end of the first portion 31. The outer peripheral edge of the connecting portion 33 is connected to the lower end of the second portion 32.

[0034] The bearing 35 is, for example, a radial ball bearing. The bearing 35 is disposed inside the first portion 31. The lower end of the outer ring of the bearing 35 in FIG. 1 is in contact with the bearing installation surface 31A. The bearing 35 may also be a thrust ball bearing.

[0035] (Rotor) The rotor 40 is cylindrical overall. The rotor 40 is disposed inside the second portion 32 of the rotor case 30. The rotor 40 integrally includes a cylindrical portion 41, a disk portion 42, and a connecting portion 43.

[0036] The cylindrical portion 41 has a plurality of north poles and a plurality of south poles. The plurality of north poles and the plurality of south poles are alternately arranged at equal angular intervals in the circumferential direction on the inner peripheral surface of the cylindrical portion 41. The plurality of north poles and the plurality of south poles extend in the vertical direction in FIG. 1. The disc portion 42 is connected to the lower end of the cylindrical portion 41 in FIG. 1. The connecting portion 43 has a cylindrical shape. The connecting portion 43 is arranged coaxially in the center of the disc portion 42 in the vertical direction in FIG. 1. The rotor 40 is a magnet rotor.

[0037] (Drive Shaft) The drive shaft 50 is made of synthetic resin or metal. The drive shaft 50 has an overall cylindrical shape. The drive shaft 50 has a male thread 51S. The male thread 51S is disposed on the outer peripheral surface of the lower portion of the drive shaft 50 in FIG. 1. The male thread 51S is threadedly engaged with the female thread 21T of the valve element 20. Note that the drive shaft 50 may have a female thread, and the valve element 20 may have a male thread. The female thread 21T and the male thread 51S form a feed screw mechanism that moves the valve element 20 in FIG. 1 in the vertical direction. The center of the drive shaft 50 is rotatably supported by the bearing 35. The drive shaft 50 has a support surface 50A, which is an annular flat surface facing downward in FIG. 1. The upper end of the inner ring of the bearing 35 contacts the support surface 50A. The upper portion of the drive shaft 50 in FIG. 1 is fitted into the connecting portion 43. The drive shaft 50 rotates together with the rotor 40.

[0038] (Can) The can 60 is cylindrical overall. The can 60 is made of, for example, a non-magnetic metal such as stainless steel. The can 60 may also be made of a synthetic resin. The can 60 integrally includes a peripheral wall portion 61, a bottom wall portion 62, and an annular portion 63.

[0039] The bottom wall portion 62 has a disk shape. The outer peripheral edge of the bottom wall portion 62 is connected to the lower end of the peripheral wall portion 61 in FIG. 1. The annular portion 63 has a circular plate shape. The inner peripheral edge of the annular portion 63 is connected to the upper end of the peripheral wall portion 61 in FIG. 1. The outer peripheral edge of the annular portion 63 is joined to the upper end of the second portion 32 of the rotor case 30 around the entire circumference in FIG. 1. The peripheral wall portion 61 and the bottom wall portion 62 are disposed inside the rotor 40. The second portion 32 of the rotor case 30 and the can 60 form a rotor space 65. The rotor 40 is disposed in the rotor space 65. The rotor space 65 is sealed from the outside of the motor-operated valve 1. The rotor space 65 is connected to the valve chamber 12 through a gap. Fluid from the valve chamber 12 is introduced into the rotor space 65.

[0040] The motor-operated valve 1 includes a housing 80, a stator 90, a control device 100, and a magnetic sensor (not shown). The housing 80, the stator 90, the control device 100, and the magnetic sensor constitute a stator unit.

[0041] The housing 80 is made of synthetic resin. The housing 80 has a housing main body 81 and a lid 85. The housing main body 81 integrally has a peripheral wall portion 82, a bottom wall portion 83, and a support portion 84. The peripheral wall portion 82 has a cylindrical shape. The bottom wall portion 83 has a disk shape. The bottom wall portion 83 is connected to the lower end of the peripheral wall portion 82 in FIG. 1. An O-ring 89 seals the gap between the bottom wall portion 83 and the annular portion 63 of the can 60.

[0042] The lid body 85 integrally includes a lid portion 86 and a connector portion 87. The lid portion 86 has a disk shape. The outer periphery of the lid portion 86 is joined to the upper end of the peripheral wall portion 82. The connector portion 87 has an elongated cylindrical shape. The connector portion 87 extends upward from the center of the upper surface of the lid portion 86 in FIG. 1. The peripheral wall portion 82, the bottom wall portion 83, and the lid portion 86 form a control device space 88.

[0043] (Control Device) The control device 100 is disposed in the control device space 88. The control device 100 has a board 101, a terminal component 102, and a computer (not shown). The board 101 is a printed circuit board on which electronic components including a computer are mounted. A plurality of coil terminals 94 of the stator 90 are connected to the board 101. The terminal component 102 has a plurality of connector terminals 103. One end of each of the plurality of connector terminals 103 is connected to the board 101, and the other end is disposed inside the connector portion 87. The computer controls the motor-operated valve 1.

[0044] The magnetic sensor (not shown) is a sensor having a Hall element that outputs a digital signal corresponding to the direction of the magnetic field. The magnetic sensor is disposed in the lower part of the housing 80 in FIG. 1. The magnetic sensor faces the magnetic poles (i.e., the north pole and the south pole) of the rotor 40 in the radial direction via the peripheral wall part 61 of the can 60. The magnetic sensor detects the magnetism of the rotor 40. The magnetic sensor is electrically connected to the substrate 101. Based on the signal output from the magnetic sensor, the computer detects the rotational position of the rotor 40.

[0045] In the motor-operated valve 1, the central axes of the main body member 11, sleeve 18, valve element support plate 19, valve element 20, rotor case 30, bearing 35, rotor 40, drive shaft 50, can 60, housing main body 81, lid body 85, and stator 90 all coincide with the central axis L. The main body member 11 has a valve chamber 12, a valve port 13, a valve seat 14, and a mounting hole 17. The lid body 85 has a lid portion 86 and a connector portion 87.

[0046] (Stepping motor) The rotor 40 and the stator 90 constitute a stepping motor 98. The rotor 40 is disposed on the outside of the peripheral wall portion 61 of the can 60. The stator 90 is fitted inside the peripheral wall portion 61 of the can 60. In the motor-operated valve 1 of this embodiment, the two stators 90 are stacked in the vertical direction in FIG. 1. The upper stator 90 in FIG. 1 is the A-phase stator, and the lower stator 90 in FIG. 1 is the B-phase stator. Note that in the present disclosure, the number of stators is arbitrary.

[0047] 1, the stator 90 has a pair of yokes 95, a plurality of claw-pole type pole teeth 96 provided on each yoke 95, a bobbin 92, a coil 93, and coil terminals 94. The stator 90 is disposed inside the can 60. That is, the motor-operated valve 1 according to this embodiment is an inner motor type.

[0048] As shown in FIGS. 2 and 3 , the yoke 95 is disk-shaped. A through-hole 95A is formed in the center of the yoke 95. A central axis L passes through the through-hole 95A. The plurality of pole teeth 96 extend from the outer periphery of the yoke 95 in the up-down direction parallel to the central axis L. In this embodiment, the yoke 95 and the plurality of pole teeth 96 are integrally formed as a single cylindrical member that is open on one side in the axial direction, for example, by press working a metal plate. The yoke 95 corresponds to the bottom of the cylindrical member, and the plurality of pole teeth 96 correspond to the side wall of the cylindrical member. In the present disclosure, a single cylindrical member may be formed by joining a yoke and a plurality of pole teeth that are separate members.

[0049] As shown in FIG. 2 , the pole teeth 96 are plate-shaped and have flat opposing surfaces 96A. The multiple pole teeth 96 are arranged at approximately equal intervals in the circumferential direction of the yoke 95. The width of the pole teeth 96 along the circumferential direction gradually narrows from the base portion on the yoke 95 side toward the tip on the opposite side from the base portion. That is, all of the multiple pole teeth 96 are triangular plate-shaped members. Therefore, the width along the circumferential direction of the gap between adjacent pole teeth 96 in the circumferential direction gradually widens from the base portion on the yoke 95 side toward the tip on the opposite side from the base portion.

[0050] A pair of yokes 95 constituting one stator 90 are arranged with a gap between them, with the pole teeth 96 of one yoke 95 positioned in the gap between the pole teeth 96 of the other yoke 95. One pole tooth 96 is arranged in one gap. In one stator 90, the pole teeth 96 of the two yokes 95 are meshed with each other. That is, a pair of cylindrical members are arranged facing each other so as to cover the opening of the other member. A bobbin 92 and a coil 93 are housed in the internal space surrounded by the two yokes 95 and their respective pole teeth 96.

[0051] The bobbin 92 is made of synthetic resin. The plurality of coil terminals 94 extend upward from the bobbin 92 in FIG.

[0052] (Protrusions) Next, the protrusions of the stator 90 according to this embodiment will be described in detail. As shown in Fig. 2, in this embodiment, all of the plurality of pole teeth 96 are provided with protrusions 97 that partially protrude from the opposing surfaces 96A toward the inner wall surface 60A of the can 60 beyond the surrounding area. In the present disclosure, it is not essential that all of the plurality of pole teeth are provided with protrusions, and it is sufficient that one or more pole teeth are provided with protrusions.

[0053] As shown in Fig. 3, the protrusion 97 protrudes toward the can 60 located radially outward. Fig. 4 illustrates an opposing surface 96A of the pole tooth 96 that faces the inner wall surface 60A of the can 60, and a curved surface 97A that is the portion of the protrusion 97 that faces the inner wall surface 60A of the can 60. In this embodiment, the curved surface 97A is curved overall without being sharp. In this disclosure, the surface of the curved portion may be partially curved. Also, in this disclosure, the curved portion is not required.

[0054] In this embodiment, the protrusion 97 is in contact with the inner wall surface 60A of the can 60. In this disclosure, it is not essential that the protrusion contact the inner wall surface of the can, and the protrusion may be separated from the inner wall surface of the can. Also, in this disclosure, all of the protrusions may be separated from the inner wall surface of the can, or only some of the protrusions may be separated from the inner wall surface of the can.

[0055] The protrusions 97 can be formed on the opposing surfaces 96A of the pole teeth 96 by, for example, press working. As shown in Fig. 4, recesses 96B formed by press working the protrusions 97 are exemplified on the surface of the pole teeth 96 opposite the opposing surfaces 96A in the radial direction. Press working makes it easy to manufacture the protrusions 97. In the present disclosure, the method for manufacturing the protrusions is not limited to press working.

[0056] 5, in this embodiment, when the opposing surface 96A is viewed from the front toward the central axis L, the pole teeth 96 are generally symmetrical about a center line LC of the pole teeth 96. The center line LC of the pole teeth 96 is parallel to the central axis L of the motor-operated valve 1. In the present disclosure, it is not essential that the pole teeth be generally symmetrical about LC, and they may be asymmetrical.

[0057] In the present embodiment, the protrusion 97 has a long, narrow dome shape extending in the vertical direction in FIG. 5 , but in the present disclosure, the shape of the protrusion is not limited to this. In the present disclosure, the shape of the protrusion may be a hemispherical dome shape, or may be other shapes such as a pyramid shape or a rod shape. Also, in the present embodiment, the case where one protrusion 97 is formed on one pole tooth 96 has been exemplified, but in the present disclosure, the number of protrusions formed on one pole tooth may be multiple.

[0058] 6, in the case of a stator 90Z according to a comparative example that does not have a protrusion 97, a gap is formed in the circumferential center between the curved inner wall surface 60A of the can 60 and the opposing surface 96A of the flat, plate-shaped pole tooth 96 that faces the inner wall surface 60A. The motor-operated valve according to the comparative example is similar in configuration to the motor-operated valve 1 according to this embodiment, except that it does not have a protrusion 97. In the comparative example, the torque loss of the motor due to the gap is greater than in this embodiment that has the protrusion 97.

[0059] <Operation of the Motor-Operated Valve> In the motor-operated valve 1 according to this embodiment, the rotor 40 can be rotated in one circumferential direction by supplying current to the multiple coils 93 of the stator 90. The drive shaft 50 rotates together with the rotor 40. Due to the feed screw action between the male thread 51S of the drive shaft 50 and the female thread 21T of the valve element 20, the valve element 20 moves downward in FIG. 1 , reducing the opening area of ​​the valve orifice 13, i.e., the throttle flow path. When the valve orifice 13 is closed by the valve element 20 coming into contact with the valve seat 14, the motor-operated valve 1 is brought into a fully closed state.

[0060] Furthermore, by supplying a current to the multiple coils 93 of the stator 90 in a direction opposite to that in which the fully closed state of the motor-operated valve 1 is achieved, the rotor 40 can be rotated in the other direction opposite to the one direction. The drive shaft 50 rotates together with the rotor 40. Due to the feed screw action between the male thread 51S of the drive shaft 50 and the female thread 21T of the valve element 20, the valve element 20 moves upward in FIG. 1, increasing the opening area of ​​the valve orifice 13. When the valve element 20 is furthest from the valve orifice 13, the motor-operated valve 1 is in the fully open state. In the fully open state of the motor-operated valve 1, the opening area of ​​the valve orifice 13 is at its largest.

[0061] (Effects) In this embodiment, all of the pole teeth 96 of the stator 90 arranged inside the can 60 are provided with protrusions 97 that partially protrude from the opposing surfaces 96A toward the inner wall surface 60A of the can 60 beyond the surrounding area. Therefore, even if the stator 90 is arranged inside the can 60, the protrusions 97 can reduce the width of the gap between the stator 90 and the can 60 compared to, for example, a pole tooth 96 whose opposing surface 96A is entirely flat. As a result, torque loss can be suppressed while the device is made more compact.

[0062] In this embodiment, the curved surface 97A of the protrusion 97 facing the inner wall surface 60A of the can 60 is curved. Therefore, even if the protrusion 97 comes into contact with the inner wall surface 60A of the can 60, the can 60 or the pole teeth 96 are unlikely to be damaged.

[0063] Furthermore, in this embodiment, the protrusion 97 is in contact with the inner wall surface 60A of the can 60. Therefore, the torque loss is more effectively suppressed than when a gap is formed between the stator 90 and the can 60 without the protrusion 97 being formed.

[0064] Furthermore, in this embodiment, when the opposing surface 96A is viewed from the front toward the central axis L, the pole teeth 96 are symmetrical with respect to the center line LC that is parallel to the central axis L. Therefore, the torque loss suppression effect is higher than when, for example, the pole teeth 96 are asymmetrical with respect to the center line LC that is parallel to the central axis L.

[0065] (Modification) In the present embodiment, the case where the corners at both ends in the circumferential direction of the pole teeth 96 contact the inner wall surface 60A of the can 60 has been exemplified, but in the present disclosure, as shown in Fig. 7, each of the corners at both ends in the circumferential direction of the pole teeth 96 may be spaced apart from the inner wall surface 60A of the can 60. Specifically, in the motor-operated valve according to the modification, the shape and dimensions of the pole teeth 96, including the shape and dimensions of the protrusions 97, are set in advance so that a gap G is formed between each of the corners at both ends in the circumferential direction of the pole teeth 96 and the inner wall surface 60A of the can 60. The configurations of the other members of the motor-operated valve according to the modification, except for the pole teeth 96, are the same as the members of the motor-operated valve 1 according to the present embodiment, and therefore redundant description will be omitted.

[0066] (Effects of the Modified Example) In the motor-operated valve according to the modified example, as in the present embodiment, even if the stator 90 is disposed inside the can 60, the protrusions 97 can reduce the width of the gap between the stator 90 and the can 60, compared to, for example, the case of pole teeth 96 whose opposing surfaces 96A are generally flat. As a result, torque loss can be suppressed while the device is made more compact.

[0067] Furthermore, in this modification, when the stator 90 is inserted inside the can 60 during assembly of the motor-operated valve, the corners at both ends in the circumferential direction of the pole teeth 96 are spaced apart from the inner wall surface 60A of the can 60, thereby suppressing damage to the inner wall surface 60A that would otherwise be caused by contact with the corners. The effect of suppressing damage to the inner wall surface 60A can be obtained not only during assembly, but also when the can 60 is deformed due to the influence of the internal pressure of the fluid during operation of the motor-operated valve, for example. Other effects of the modification are the same as those of the present embodiment.

[0068] Although the present disclosure has been described based on the above disclosed embodiments, the descriptions and drawings that form part of this disclosure should not be understood to limit the present disclosure. For example, the present disclosure can be configured by partially combining the configurations illustrated in the attached drawings. The present disclosure includes various embodiments not described above, and the technical scope of the present disclosure is defined only by the invention-specific matters in the scope of the claims that are appropriate from the above description.

[0069] The disclosure of Japanese Patent Application No. 2024-115060, filed on July 18, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. An electric valve comprising: a cylindrical can; a cylindrical rotor arranged outside the can; a valve body that moves in accordance with the rotation of the rotor; and a stator arranged inside the can, the stator having a plurality of plate-shaped pole teeth with flat opposing surfaces that face the inner wall surface of the can, and one or more of the pole teeth having a protrusion that partially protrudes from the opposing surface toward the inner wall surface of the can beyond its surroundings.

2. The motor-operated valve according to claim 1, wherein the portion of the protrusion facing the inner wall surface of the can is curved.

3. The motor-operated valve according to claim 1 or 2, wherein the protrusion is in contact with the inner wall surface of the can.

4. The motor-operated valve according to any one of claims 1 to 3, wherein, when the opposing surfaces are viewed from the front toward the central axis, the pole teeth are symmetrical with respect to a center line parallel to the central axis.

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