Stator and electric valve

Abstract

A stator and an electric valve are provided that can suppress deterioration in assembly workability and suppress variation in motor torque. [Solution] The motor-operated valve has a valve body assembly and a stator unit 6. The stator unit 6 has a stator core 70. The stator core 70 has a back yoke 71, an A-phase pole set 80, and a B-phase pole set 90. The back yoke 71 has an inner space 72 and an opening 73. The A-phase pole set 80 has an A-phase main pole 81a and an A-phase first auxiliary pole 85, which form a magnetic circuit. The B-phase pole set 90 has a B-phase main pole 91a and a B-phase first auxiliary pole 95, which form a magnetic circuit.

Description

Technical Field

[0001] The present invention relates to a stator and an electric valve having the stator.

Background Art

[0002] An example of a conventional electric valve is disclosed in Patent Document 1. This electric valve is incorporated in, for example, an air conditioner and is used to control the flow rate of refrigerant. The electric valve has a valve body assembly and a stator unit. The valve body assembly has a refrigerant inlet portion, a flow rate control portion, and a refrigerant outlet portion that form a linear flow path, and a magnet rotor disposed inside the flow rate control portion. The stator unit has a stator disposed outside the flow rate control portion. The magnet rotor and the stator constitute a stepping motor. The electric valve is incorporated in series in a linear pipe of an air conditioner.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The stator generally has an annular shape, and the valve body assembly is inserted inside the stator. FIG. 16 shows an example of a stator core of the annular stator. The stator core 770 in FIG. 16 integrally has a back yoke 771 and a plurality of poles 781 (eight poles). The back yoke 771 has an annular shape. The plurality of poles 78l extend from the inner peripheral surface of the back yoke 771 toward its central axis L. An A - phase coil and a B - phase coil (not shown) are wound around the plurality of poles 781. The A - phase coil and the B - phase coil are alternately arranged in the circumferential direction.

[0005] It is preferable that the stator unit be attached to the valve body assembly after the valve body assembly has been installed in the air conditioner's piping. However, because the stator has an annular shape, the stator unit must be attached to the valve body assembly before the valve body assembly is installed in the air conditioner's piping. Furthermore, the electric valve (finished product), including the valve body assembly and stator unit, is large and heavy, which can reduce the workability when installing the electric valve into the air conditioner.

[0006] By using a C-shaped (arc-shaped) stator in an electric valve, the stator unit can be easily attached to the valve body assembly after the valve body assembly has been installed in the air conditioner's piping. Figure 17 shows an example of a stator core of a C-shaped stator. The stator core 870 in Figure 17 has a back yoke 871 and a plurality of poles 881 (6 poles). The back yoke 871 has a C shape. The plurality of poles 881 extend from the inner surface of the back yoke 871 toward its central axis L. Phase A coils and phase B coils (not shown) are wound around the plurality of poles 881. The phase A coils and phase B coils are arranged alternately in the circumferential direction.

[0007] In Figures 16 and 17, [A] represents a pole with an A-phase coil wound in the forward direction, [A'] represents a pole with an A-phase coil wound in the reverse direction, [B] represents a pole with a B-phase coil wound in the forward direction, and [B'] represents a pole with a B-phase coil wound in the reverse direction.

[0008] In an electric valve having a ring-shaped stator, when the A-phase coil and B-phase coil are energized to rotate the rotor, the multiple poles 781 are magnetized such that each pole is adjacent to one pole 781 of a different polarity and one pole 781 of the same polarity (Figures 18A to 18D). As a result, all of the multiple poles 781 consistently form a magnetic circuit, and the magnitude of the torque remains constant when the rotor rotates by a predetermined angle, as shown in Figure 20A.

[0009] On the other hand, in an electric valve having a C-shaped stator, when the A-phase coil and B-phase coil are energized to rotate the rotor, the four central poles 881 of the multiple poles 881 are magnetized such that each pole is adjacent to one pole 881 of a different polarity and one pole 881 of the same polarity. However, the poles 881 (881a) at both ends may be adjacent to poles 881 of a different polarity (Figures 19A and 19C) or to poles 881 of the same polarity (Figures 19B and 19C). As a result, some of the multiple poles 781 may not form a magnetic circuit, and as shown in Figure 20B, the magnitude of the torque varies when the rotor rotates by a predetermined angle.

[0010] In Figures 18A to 18D and 19A to 19D, "+I" indicates that a current is supplied to the A-phase coil and B-phase coil flowing in one direction, and "-I" indicates that a current is supplied to the A-phase coil and B-phase coil flowing in other directions. The dashed lines schematically represent the magnetic circuit.

[0011] Therefore, the present invention aims to provide a stator and an electric valve that can suppress a decrease in assembly workability and suppress variations in motor torque. [Means for solving the problem]

[0012] To achieve the above objective, a stator according to one aspect of the present invention is a stator used in an electric valve, wherein the stator comprises a stator core and a coil, the stator core comprises a back yoke and a pole set, the back yoke comprises an inner space extending from one end face to the other end face of the back yoke and an opening provided on the outer surface of the back yoke, extending from one end face to the other end face and communicating with the inner space, the pole set comprises a main pole on which the coil is arranged and an auxiliary pole, the main pole and the auxiliary pole protrude from an inner surface defining the inner space in the back yoke toward the central axis of the inner space, are adjacent to each other around the central axis, and the auxiliary pole forms a magnetic circuit together with the main pole when the coil is energized.

[0013] To achieve the above objective, another aspect of the present invention provides a stator used in an electric valve, wherein the stator comprises a stator core, a plurality of A-phase coils, and a plurality of B-phase coils, the stator core comprises a back yoke, an A-phase pole set, and a B-phase pole set, the back yoke comprises an inner space extending from one end face to the other end face of the back yoke, and an opening provided on the outer surface of the back yoke, extending from the one end face to the other end face and communicating with the inner space, the A-phase pole set comprises a plurality of A-phase main poles and an A-phase first auxiliary pole, the B-phase pole set comprises a plurality of B-phase main poles and a B-phase first auxiliary pole, the plurality of A-phase main poles, the A-phase first auxiliary poles, the plurality of B-phase main poles and the B-phase first auxiliary poles protrude from the inner surface defining the inner space in the back yoke toward the central axis of the inner space, the plurality of A-phase main poles are arranged around the central axis, and the A-phase 1. An auxiliary pole is adjacent to an A-phase main pole at one end of the row of A-phase main poles around the central axis, the row of B-phase main poles is arranged around the central axis, the B-phase first auxiliary pole is adjacent to a B-phase main pole at one end of the row of B-phase main poles around the central axis, the row of A-phase coils has A-phase coils wound in the forward direction and A-phase coils wound in the reverse direction, which are alternately arranged on the row of A-phase main poles, and the row of B-phase coils is adjacent to the row of B-phase main poles The device comprises alternatingly arranged B-phase coils wound in the forward direction and B-phase coils wound in the reverse direction, wherein the A-phase first auxiliary pole forms a magnetic circuit together with the A-phase main pole when the plurality of A-phase coils are energized, the B-phase first auxiliary pole forms a magnetic circuit together with the B-phase main pole when the plurality of B-phase coils are energized, and the A-phase first auxiliary pole and the B-phase first auxiliary pole are adjacent to each other around the central axis and face the opening across the central axis.

[0014] In the present invention, it is preferable that the A-phase pole set further comprises an A-phase second auxiliary pole, the B-phase pole set further comprises a B-phase second auxiliary pole, the A-phase second auxiliary pole and the B-phase second auxiliary pole protrude from the inner surface toward the central axis, the A-phase second auxiliary pole is adjacent around the central axis to the A-phase main pole at the other end of the row of A-phase main poles, the B-phase second auxiliary pole is adjacent around the central axis to the B-phase main pole at the other end of the row of B-phase main poles, the A-phase second auxiliary pole forms a magnetic circuit together with the A-phase main pole when the row of A-phase coils is energized, and the B-phase second auxiliary pole forms a magnetic circuit together with the B-phase main pole when the row of B-phase coils is energized.

[0015] To achieve the above objective, another aspect of the present invention provides a stator used in an electric valve, wherein the stator comprises a stator core, an A-phase coil, and a B-phase coil, the stator core comprises a back yoke, an A-phase pole set, and a B-phase pole set, the back yoke comprises an inner space extending from one end face to the other end face of the back yoke, and an opening provided on the outer surface of the back yoke, extending from one end face to the other end face and communicating with the inner space, the A-phase pole set comprises an A-phase main pole on which the A-phase coil is arranged, an A-phase first auxiliary pole, and an A-phase second auxiliary pole, the B-phase pole set comprises a B-phase main pole on which the B-phase coil is arranged, a B-phase first auxiliary pole, and a B-phase second auxiliary pole, and the A-phase main pole, the A-phase first auxiliary pole, and the A-phase second auxiliary The auxiliary pole, the B-phase main pole, the B-phase first auxiliary pole, and the B-phase second auxiliary pole protrude from the inner surface defining the inner space in the back yoke toward the central axis of the inner space, the A-phase first auxiliary pole, the A-phase main pole, and the A-phase second auxiliary pole are arranged in this order around the central axis, the B-phase first auxiliary pole, the B-phase main pole, and the B-phase second auxiliary pole are arranged in this order around the central axis, the A-phase first auxiliary pole and the A-phase second auxiliary pole form a magnetic circuit together with the A-phase main pole when the A-phase coil is energized, the B-phase first auxiliary pole and the B-phase second auxiliary pole form a magnetic circuit together with the B-phase main pole when the B-phase coil is energized, and the opening is located between the A-phase pole set and the B-phase pole set.

[0016] To achieve the above objective, another electric valve according to another aspect of the present invention is an electric valve having a stator and a valve body assembly, wherein the valve body assembly has a cylindrical shape and comprises a valve body disposed in the inner space and a magnet rotor disposed inside the valve body and constituting a motor together with the stator, and pipelines are connected to one end and the other end of the valve body. [Effects of the Invention]

[0017] According to the present invention, the back yoke has an inner space and an opening leading to the inner space. Since it is configured in this way, a pipeline can be inserted into the inner space through the opening, and the valve body assembly can be arranged in the inner space. Therefore, it is possible to suppress a decrease in the workability of the incorporation work. Further, a main pole having a coil and an auxiliary pole not having a coil are adjacent to each other around the central axis of the inner space, and when the coil is energized, the main pole and the auxiliary pole form a magnetic circuit. Since it is configured in this way, the main pole and the auxiliary pole can consistently form a magnetic circuit even when the current is switched. Therefore, it is possible to suppress variations in the torque of the motor.

Brief Description of Drawings

[0018] [Figure 1] It is a perspective view of an electric valve according to an embodiment of the present invention. [Figure 2] It is a perspective view of a valve body assembly included in the electric valve. [Figure 3] It is a perspective view of a stator unit included in the electric valve. [Figure 4] It is a cross-sectional view taken along line IV-IV of FIG. 3. [Figure 5] It is a cross-sectional view taken along line V-V of FIG. 4. [Figure 6] It is a cross-sectional view of a stator core included in the stator unit. [Figure 7] It is a diagram for explaining an assembling method of the electric valve. [Figure 8] It is a diagram schematically showing a magnetic circuit formed in the stator core (Part 1). [Figure 9] It is a diagram schematically showing a magnetic circuit formed in the stator core (Part 2). [Figure 10] It is a diagram schematically showing a magnetic circuit formed in the stator core (Part 3). [Figure 11] It is a diagram schematically showing a magnetic circuit formed in the stator core (Part 4). [Figure 12]It is a cross-sectional view showing the configuration of a first modified example of the stator unit in FIG. 3. [Figure 13] It is a diagram schematically showing a magnetic circuit formed in a stator core included in the stator unit of FIG. 12. [Figure 14] It is a cross-sectional view showing the configuration of a second modified example of the stator unit in FIG. 3. [Figure 15] It is a diagram schematically showing a magnetic circuit formed in a stator core included in the stator unit of FIG. 14. [Figure 16] It is a cross-sectional view of a stator core included in an annular stator. [Figure 17] It is a cross-sectional view of a stator core included in a C-shaped stator. [Figure 18] It is a diagram schematically showing a magnetic circuit formed in the stator core of FIG. 16. [Figure 19] It is a diagram schematically showing a magnetic circuit formed in the stator core of FIG. 17. [Figure 20] It is a graph showing the magnitude of torque when the rotor rotates.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, an electric valve according to an embodiment of the present invention will be described with reference to FIGS. 1 to 11.

[0020] FIG. 1 is a perspective view of an electric valve according to an embodiment of the present invention. FIG. 2 is a perspective view of a valve body assembly included in the electric valve. FIG. 3 is a perspective view of a stator unit included in the electric valve. FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3. FIG. 5 is a cross-sectional view taken along line V-V of FIG. 4. FIG. 6 is a cross-sectional view of a stator core included in the stator unit. FIG. 7 is a diagram for explaining an assembling method of the electric valve. FIGS. 8 to 11 are diagrams schematically showing magnetic circuits formed in the stator core.

[0021] The electric valve 1 according to the present embodiment is, for example, incorporated in series in a linear pipeline of an air conditioner and used to control the flow rate of refrigerant.

[0022] As shown in Figures 1 to 3, the electric valve 1 comprises a valve body assembly 5 and a stator unit 6.

[0023] The valve body assembly 5 comprises a valve body 10 and a rotor 30.

[0024] The valve body 10 includes a case 11, a cover member 12, and a valve seat member 13. The case 11, cover member 12, and valve seat member 13 are made of metal, such as stainless steel or an aluminum alloy.

[0025] Case 11 has a cylindrical shape. Case 11 is arranged along axis L. The lid member 12 has a disc shape. The lid member 12 is joined to one end 11a of case 11 and closes that end 11a.

[0026] The valve seat member 13 has a cover portion 14. The cover portion 14 has a disc shape. The cover portion 14 is joined to the other end 11b of the case 11 and closes the other end 11b.

[0027] The valve seat member 13 has a valve opening (not shown) and a valve seat surrounding the valve opening. The case 11, the cover member 12, and the valve seat member 13 form a valve chamber (not shown). A first conduit 8 is joined to the cover member 12, and the first conduit 8 is connected to the valve chamber. A second conduit 9 is joined to the cover member 14, and the second conduit 9 is connected to the valve chamber through the valve opening. The first conduit 8 and the second conduit 9 are the conduits of the air conditioner.

[0028] The rotor 30 is a magnetic rotor. The rotor 30 has a cylindrical shape and is positioned in the valve chamber along the axis L. The rotor 30 is rotatable relative to the valve body 10. The rotor 30 has multiple magnetic poles (multiple north poles and multiple south poles). The multiple north poles and multiple south poles are arranged alternately at equal angular intervals in the circumferential direction (Figure 8). The multiple north poles and multiple south poles extend in the direction of the axis L. For example, the rotor 30 has 12 north poles and 12 south poles. The angle between two adjacent magnetic poles around the axis L (magnetic pole spacing α) is 15 degrees.

[0029] A valve body (not shown) is connected to the rotor 30. When the rotor 30 rotates in one direction, the valve body moves closer to the valve seat, and the valve opening decreases. When the rotor 30 rotates in the other direction, the valve body moves away from the valve seat, and the valve opening increases.

[0030] The stator unit 6 is positioned along the axis L. The stator unit 6 is attached to the valve body assembly 5. As shown in Figures 4 and 5, the stator unit 6 includes a stator 60 and a cover 100.

[0031] The stator 60, together with the rotor 30, constitutes a stepping motor. The rotor 30 and stator 60 may constitute a motor other than a stepping motor. The stator 60 has a stator core 70, a plurality of A-phase coils 88, and a plurality of B-phase coils 98.

[0032] The stator core 70 is formed, for example, by stacking multiple thin electromagnetic steel sheets. As shown in Figure 6, the stator core 70 includes a back yoke 71, an A-phase pole set 80, and a B-phase pole set 90.

[0033] The back yoke 71 has a substantially cylindrical shape. The back yoke 71 has an inner space 72 and an opening 73. The inner space 72 extends from one end face 71a to the other end face 71b of the back yoke 71. The opening 73 is provided on the outer surface 71c of the back yoke 71 and extends from one end face 71a to the other end face 71b. The opening 73 is connected to the inner space 72. The inner surface 71d of the back yoke 71 defines the inner space 72. When viewed from the direction of the axis L, the back yoke 71 has a C shape (arc shape).

[0034] The A-phase pole set 80 includes a plurality of A-phase main poles 81 (for example, three A-phase main poles 81) and an A-phase first auxiliary pole 85. The plurality of A-phase main poles 81 and the A-phase first auxiliary pole 85 protrude from the inner surface 71d of the back yoke 71 toward the axis L. The plurality of A-phase main poles 81 and the A-phase first auxiliary pole 85 extend from one end face 71a to the other end face 71b of the back yoke 71.

[0035] Multiple A-phase main poles 81 are arranged around axis L. In the following description, the pole at one end of the arrangement of multiple A-phase main poles 81 will be called A-phase main pole 81a, the one in the middle will be called A-phase main pole 81b, and the one at the other end will be called A-phase main pole 81c. An A-phase pole set 80 may have two A-phase main poles 81, or it may have four or more A-phase main poles 81.

[0036] Each of the multiple A-phase main poles 81 has a support column 82 and two teeth 83. The support column 82 extends from the inner surface 71d toward the axis L. An A-phase coil 88 is wound around the support column 82. The two teeth 83 are located at the tip of the support column 82 and are aligned around the axis L. The distance (angle) between the two teeth 83 around the axis L is twice the pole spacing α. The width (angle) of each tooth 83 around the axis L is half the pole spacing α. The distance (angle) between the teeth 83 of two adjacent A-phase main poles around the axis L is the same as the pole spacing α.

[0037] The A-phase first auxiliary pole 85 is adjacent to the A-phase main pole 81a around axis L. The width (angle) of the tip of the A-phase first auxiliary pole 85 around axis L is half the pole spacing α. The distance (angle) between the tip of the A-phase first auxiliary pole 85 and the teeth 83 of the A-phase main pole 81a around axis L is the same as the pole spacing α.

[0038] The B-phase pole set 90 has a plurality of B-phase main poles 91 (for example, three B-phase main poles 91) and a B-phase first auxiliary pole 95. The plurality of B-phase main poles 91 and the B-phase first auxiliary pole 95 protrude from the inner surface 71d of the back yoke 71 toward the axis L. The plurality of B-phase main poles 91 and the B-phase first auxiliary pole 95 extend from one end face 71a to the other end face 71b of the back yoke 71.

[0039] Multiple B-phase main poles 91 are arranged around axis L. In the following description, the pole at one end of the arrangement of multiple B-phase main poles 91 is also called B-phase main pole 91a, the one in the middle is also called B-phase main pole 91b, and the one at the other end is also called B-phase main pole 91c. A B-phase pole set 90 may have two B-phase main poles 91, or it may have four or more B-phase main poles 91.

[0040] Each of the multiple B-phase main poles 91 has a support column 92 and two teeth 93. The support column 92 extends from the inner surface 71d toward the axis L. The B-phase coil 98 is wound around the support column 92. The two teeth 93 are located at the tip of the support column 92 and are aligned around the axis L. The distance (angle) between the two teeth 93 around the axis L is twice the pole spacing α. The width (angle) of each tooth 93 around the axis L is half the pole spacing α. The distance (angle) between the teeth 93 of two adjacent B-phase main poles around the axis L is the same as the pole spacing α.

[0041] The B-phase first auxiliary pole 95 is adjacent to the B-phase main pole 91a around axis L. The width (angle) of the tip of the B-phase first auxiliary pole 95 around axis L is half the pole spacing α. The distance (angle) between the tip of the B-phase first auxiliary pole 95 and the teeth 93 of the B-phase main pole 91a around axis L is the same as the pole spacing α.

[0042] The A-phase pole set 80 and the B-phase pole set 90 face each other across axis L. The A-phase pole set 80 and the B-phase pole set 90 are mirror images of each other. The number of A-phase main poles 81 in the A-phase pole set 80 is the same as the number of B-phase main poles 91 in the B-phase pole set 90. The A-phase first auxiliary pole 85 and the B-phase first auxiliary pole 95 are adjacent to each other around axis L. The A-phase first auxiliary pole 85 and the B-phase first auxiliary pole 95 face the opening 73 across axis L.

[0043] The multiple A-phase coils 88 have A-phase coils 88 wound in the forward direction and A-phase coils 88 wound in the reverse direction, which are alternately arranged around the axis L on the multiple A-phase main poles 81. Specifically, the A-phase coil 88 wound in the forward direction is placed on the A-phase main pole 81b (center), and the A-phase coils 88 wound in the reverse direction are placed on the A-phase main poles 81a and 81c (one end and the other end). The multiple A-phase coils 88 are connected in series. When the multiple A-phase coils 88 are energized, the A-phase main pole 81b and the A-phase main poles 81a and 81c are magnetized to different polarities. No coils are placed on the A-phase first auxiliary pole 85.

[0044] The multiple B-phase coils 98 have B-phase coils 98 wound in the forward direction and B-phase coils 98 wound in the reverse direction, which are alternately arranged around the axis L on the multiple B-phase main poles 91. Specifically, the B-phase coil 98 wound in the forward direction is placed on the B-phase main pole 91b (center), and the B-phase coils 98 wound in the reverse direction are placed on the B-phase main poles 91a and 91c (one end and the other end). The multiple B-phase coils 98 are connected in series. When the multiple B-phase coils 98 are energized, the B-phase main pole 91b and the B-phase main poles 91a and 91c are magnetized to different polarities. No coils are placed on the B-phase first auxiliary pole 95.

[0045] Multiple A-phase coils 88 and multiple B-phase coils 98 are monofilar-wound coils. A monofilar-wound coil consists of a single coil wound in one direction. Multiple A-phase coils 88 and multiple B-phase coils 98 may also be bifilar-wound coils. A bifilar-wound coil consists of two coils wound in the forward and reverse directions, or a coil wound in one direction with a common terminal drawn from its midpoint. When multiple A-phase coils 88 are bifilar-wound, the multiple A-phase coils 88 are energized such that the A-phase main poles 81b and 81a, 81c are magnetized to different polarities. When multiple B-phase coils 98 are bifilar-wound, the multiple B-phase coils 98 are energized such that the B-phase main poles 91b and 91a, 91c are magnetized to different polarities.

[0046] The cover 100 has a shape that conforms to the outer shape of the stator 60 and covers the stator 60. When viewed from the direction of the axis L, the cover 100 has a C shape (arc shape). The cover 100 is made of synthetic resin and is integrally molded with the stator 60. The inner surface of the cover 100, together with the two teeth 83 of the A-phase main pole 81, the tip of the A-phase first auxiliary pole 85, the two teeth 93 of the B-phase main pole 91, and the tip of the B-phase first auxiliary pole 95, forms the inner surface 6d of the stator unit 6. The cover 100 may be omitted in the stator unit 6.

[0047] The stator unit 6 has an inner space 6s and an opening 6e. The inner space 6s extends from one end face 6a to the other end face 6b of the stator unit 6. The opening 6e is provided on the outer surface 6c of the stator unit 6, extends from one end face 6a to the other end face 6b, and is connected to the inner space 6s. The inner space 6s is defined by the inner surface 6d of the stator unit 6. The diameter of the inner space 6s is the same as the diameter of the valve body assembly 5. The valve body assembly 5 is positioned in the inner space 6s. The central part of the inner space 6s overlaps with the inner space 72 of the stator core 70. The central part of the opening 6e overlaps with the opening 73 of the stator core 70. The width of the opening 6e (opening 73) is greater than the outer diameter of the first conduit 8 and the outer diameter of the second conduit 9.

[0048] In this embodiment, the central axes of the valve body assembly 5 (valve body 10 and rotor 30), the stator unit 6 (inner space 6s, stator 60 and cover 100), the first conduit 8, and the second conduit 9 all coincide with axis L. The central axis of the inner space 72 of the back yoke 71 coincides with axis L.

[0049] Next, the method for attaching the stator unit 6 to the valve body assembly 5 will be explained with reference to Figures 7A to 7C.

[0050] As shown in Figure 7A, the valve body assembly 5 is connected to the first conduit 8 and the second conduit 9. The opening 6e of the stator unit 6 is positioned opposite the first conduit 8, and the stator unit 6 is moved toward the first conduit 8.

[0051] As shown in Figure 7B, the first conduit 8 is inserted into the inner space 6s through the opening 6e of the stator unit 6, and the first conduit 8 is coaxially positioned in the inner space 6s of the stator unit 6.

[0052] As shown in Figure 7C, the stator unit 6 is moved in the direction of the axis L, and the valve body assembly 5 is inserted into the inner space 6s of the stator unit 6. Then, the stator unit 6 is attached to the valve body assembly 5 by a mounting mechanism (not shown), and the electric valve 1 is completed.

[0053] Next, the magnetic circuit formed in the stator core 70 when the A-phase coil 88 and B-phase coil 98 of the stator 60 are energized will be described with reference to Figures 8 to 11.

[0054] In Figures 8 to 11, [A] shows the A-phase main pole 81 where the A-phase coil 88 wound in the forward direction is located, [A'] shows the A-phase main pole 81 where the A-phase coil 88 wound in the reverse direction is located, [B] shows the B-phase main pole 91 where the B-phase coil 98 wound in the forward direction is located, and [B'] shows the B-phase main pole 91 where the B-phase coil 98 wound in the reverse direction is located. In Figures 8 to 11, "+I" indicates that a current is supplied to the A-phase coil 88 and B-phase coil 98 flowing in one direction, and "-I" indicates that a current is supplied to the A-phase coil 88 and B-phase coil 98 flowing in other directions. The dashed lines schematically represent the magnetic circuit, and black circles are placed on the reference magnetic poles of the rotor 30.

[0055] A current is supplied to the A-phase coil 88, flowing in one direction. When a current flowing in the opposite direction is supplied to the B-phase coil 98, The A-phase main poles 81a, 81b, and 81c become the S pole, N pole, and S pole, respectively. The main B-phase poles 91a, 91b, and 91c become the north pole, south pole, and north pole, respectively. As a result, The A-phase first auxiliary pole 85 and the A-phase main pole 81a form a magnetic circuit Ma1. The A-phase main pole 81a and the A-phase main pole 81b form a magnetic circuit Ma2. The A-phase main pole 81b and the A-phase main pole 81c form a magnetic circuit Ma3. The B-phase first auxiliary pole 95 and the B-phase main pole 91a form a magnetic circuit Mb1. The B-phase main pole 91a and the B-phase main pole 91b form a magnetic circuit Mb2. The B-phase main pole 91b and the B-phase main pole 91c form a magnetic circuit Mb3. The rotor 30 rotates clockwise by an angle equal to half the pole spacing α, and is positioned as shown in Figure 8.

[0056] A current is supplied to the A-phase coil 88, flowing in one direction. When a current flowing in one direction is supplied to the B-phase coil 98, The A-phase main poles 81a, 81b, and 81c become the S pole, N pole, and S pole, respectively. The main B-phase poles 91a, 91b, and 91c become the south pole, north pole, and south pole, respectively. As a result, The A-phase first auxiliary pole 85 and the A-phase main pole 81a form a magnetic circuit Ma1. The A-phase main pole 81a and the A-phase main pole 81b form a magnetic circuit Ma2. The A-phase main pole 81b and the A-phase main pole 81c form a magnetic circuit Ma3. The B-phase first auxiliary pole 95 and the B-phase main pole 91a form a magnetic circuit Mb1. The B-phase main pole 91a and the B-phase main pole 91b form a magnetic circuit Mb2. The B-phase main pole 91b and the B-phase main pole 91c form a magnetic circuit Mb3. The rotor 30 rotates clockwise by an angle equal to half the pole spacing α, and is positioned as shown in Figure 9.

[0057] A current is supplied to the A-phase coil 88, flowing in the opposite direction. When a current flowing in one direction is supplied to the B-phase coil 98, The A-phase main poles 81a, 81b, and 81c become the north pole, south pole, and north pole, respectively. The main B-phase poles 91a, 91b, and 91c become the south pole, north pole, and south pole, respectively. As a result, The A-phase first auxiliary pole 85 and the A-phase main pole 81a form a magnetic circuit Ma1. The A-phase main pole 81a and the A-phase main pole 81b form a magnetic circuit Ma2. The A-phase main pole 81b and the A-phase main pole 81c form a magnetic circuit Ma3. The B-phase first auxiliary pole 95 and the B-phase main pole 91a form a magnetic circuit Mb1. The B-phase main pole 91a and the B-phase main pole 91b form a magnetic circuit Mb2. The B-phase main pole 91b and the B-phase main pole 91c form a magnetic circuit Mb3. The rotor 30 rotates clockwise by an angle equal to half the pole spacing α, and is positioned as shown in Figure 10.

[0058] A current is supplied to the A-phase coil 88, flowing in the opposite direction. When a current flowing in the opposite direction is supplied to the B-phase coil 98, The A-phase main poles 81a, 81b, and 81c become the north pole, south pole, and north pole, respectively. The main B-phase poles 91a, 91b, and 91c become the north pole, south pole, and north pole, respectively. As a result, The A-phase first auxiliary pole 85 and the A-phase main pole 81a form a magnetic circuit Ma1. The A-phase main pole 81a and the A-phase main pole 81b form a magnetic circuit Ma2. The A-phase main pole 81b and the A-phase main pole 81c form a magnetic circuit Ma3. The B-phase first auxiliary pole 95 and the B-phase main pole 91a form a magnetic circuit Mb1. The B-phase main pole 91a and the B-phase main pole 91b form a magnetic circuit Mb2. The B-phase main pole 91b and the B-phase main pole 91c form a magnetic circuit Mb3. The rotor 30 rotates clockwise by an angle equal to half the pole spacing α, and is positioned as shown in Figure 11.

[0059] Thus, when current is supplied to the A-phase coil 88 and the B-phase coil 98 so that the rotor 30 rotates, all the A-phase main poles 81 and all the B-phase main poles 91 consistently form a magnetic circuit, and a similar magnetic circuit is formed even when the current is switched.

[0060] As described above, the electric valve 1 comprises a valve body assembly 5 and a stator unit 6. The valve body assembly 5 has a cylindrical shape and comprises a valve body 10 which is placed in the inner space 6s of the stator unit 6 (the inner space 72 of the stator core 70) and a rotor 30 which is placed inside the case 11 of the valve body 10. A first conduit 8 is connected to the cover member 12 of the valve body 10 (one end of the valve body 10). A second conduit 9 is connected to the valve seat member 13 of the valve body 10 (the other end of the valve body 10).

[0061] The stator unit 6 has a stator 60. The stator 60 has a stator core 70, a plurality of A-phase coils 88, and a plurality of B-phase coils 98. The stator core 70 has a back yoke 71, an A-phase pole set 80, and a B-phase pole set 90. The back yoke 71 has an inner space 72 extending from one end face 71a to the other end face 71b, and an opening 73 provided on the outer surface 71c, extending from one end face 71a to the other end face 71b and communicating with the inner space 72. The A-phase pole set 80 has a plurality of A-phase main poles 81 and an A-phase first auxiliary pole 85. The B-phase pole set 90 has a plurality of B-phase main poles 91 and a B-phase first auxiliary pole 95. Multiple A-phase main poles 81, A-phase first auxiliary poles 85, multiple B-phase main poles 91, and B-phase first auxiliary poles 95 protrude from the inner surface 71d of the back yoke 71 toward the axis L. Multiple A-phase main poles 81 are arranged around the axis L, and the A-phase first auxiliary poles 85 are adjacent around the axis L to an A-phase main pole 81a at one end of the arrangement of multiple A-phase main poles 81. Multiple B-phase main poles 91 are arranged around the axis L, and the B-phase first auxiliary poles 95 are adjacent around the axis L to an A-phase main pole 91a at one end of the arrangement of multiple B-phase main poles 91. Multiple A-phase coils 88 are arranged alternately on the multiple A-phase main poles 81, and include A-phase coils 88 wound in the forward direction and A-phase coils 88 wound in the reverse direction. The B-phase coils 98 are arranged alternately on the B-phase main poles 91, and include B-phase coils 98 wound in the forward direction and B-phase coils 98 wound in the reverse direction. When the A-phase coils 88 are energized, the A-phase first auxiliary pole 85 forms a magnetic circuit Ma1 together with the A-phase main pole 81a. When the B-phase coils 98 are energized, the B-phase first auxiliary pole 95 forms a magnetic circuit Mb1 together with the B-phase main pole 91a. The A-phase first auxiliary pole 85 and the B-phase first auxiliary pole 95 are adjacent to each other around the axis L and face the opening 73 across the axis L.

[0062] The stator unit 6 has an inner space 6s (inner space 72 of the back yoke 71) and an opening 6e (opening 73 of the back yoke 71). In this way, the air conditioner piping can be inserted into the inner space 6s through the opening 6e, and the valve body assembly 5 can be placed in the inner space 6s. Therefore, a decrease in the ease of assembly of the electric valve 1 can be suppressed.

[0063] Furthermore, in a configuration where the stator core 70 does not have the A-phase first auxiliary pole 85 and the B-phase first auxiliary pole 95, in the states shown in Figures 8 and 10, instead of magnetic circuits Ma1 and Mb1, the A-phase main pole 81a and the B-phase main pole 91a have different polarities and form a magnetic circuit. However, in the states shown in Figures 9 and 11, the A-phase main pole 81a and the B-phase main pole 91a have the same polarity and do not form a magnetic circuit. As a result, the magnitude of the torque when the rotor 30 rotates varies. On the other hand, in the stator 60 according to this embodiment, the A-phase main pole 81a and the A-phase first auxiliary pole 85 are adjacent to each other around the axis L, and when the A-phase coil 88 is energized, the A-phase main pole 81a and the A-phase first auxiliary pole 85 form a magnetic circuit Ma1. The B-phase main pole 91a and the B-phase first auxiliary pole 95 are adjacent to each other around the axis L, and when the B-phase coil 98 is energized, the B-phase main pole 91a and the B-phase first auxiliary pole 95 form a magnetic circuit Mb1. Therefore, even when the current switches, the same magnetic circuit is formed, so the magnitude of the torque when the rotor 30 rotates remains constant. Consequently, variations in the torque of the stepping motor of the electric valve 1 can be suppressed.

[0064] Next, modified examples of the stator unit 6 will be described with reference to Figures 12 to 15. In the description of each embodiment, components identical (including substantially identical) to the stator unit 6 described above are denoted by the same reference numerals, and detailed descriptions are omitted.

[0065] Figure 12 is a cross-sectional view of a stator unit 6A according to a first modified example of the stator unit 6. Figure 13 is a schematic diagram showing the magnetic circuit formed in the stator core 70A of the stator unit 6A of Figure 12. In Figure 13, the dashed lines schematically represent the magnetic circuit.

[0066] The stator unit 6A includes a stator 60A and a cover 100. The stator 60A includes a stator core 70A, a plurality of A-phase coils 88, and a plurality of B-phase coils 98. The stator core 70A includes a back yoke 71, an A-phase pole set 80A, and a B-phase pole set 90A.

[0067] The A-phase pole set 80A includes a plurality of A-phase main poles 81 (A-phase main poles 81a, 81b, 81c), an A-phase first auxiliary pole 85, and an A-phase second auxiliary pole 86. The plurality of A-phase main poles 81, the A-phase first auxiliary pole 85, and the A-phase second auxiliary pole 86 protrude from the inner surface 71d of the back yoke 71 toward the axis L. The A-phase main poles 81, the A-phase first auxiliary pole 85, and the A-phase second auxiliary pole 86 extend from one end face 71a to the other end face 71b of the back yoke 71.

[0068] The A-phase second auxiliary pole 86 is adjacent to the A-phase main pole 81c around axis L. The width (angle) of the tip of the A-phase second auxiliary pole 86 around axis L is half the pole spacing α. The distance (angle) of the tip of the A-phase second auxiliary pole 86 and the teeth 83 of the A-phase main pole 81c around axis L is the same as the pole spacing α.

[0069] The B-phase pole set 90A includes a plurality of B-phase main poles 91 (B-phase main poles 91a, 91b, 91c), a B-phase first auxiliary pole 95, and a B-phase second auxiliary pole 96. The plurality of B-phase main poles 91, the B-phase first auxiliary pole 95, and the B-phase second auxiliary pole 96 protrude from the inner surface 71d of the back yoke 71 toward the axis L. The plurality of B-phase main poles 91, the B-phase first auxiliary pole 95, and the B-phase second auxiliary pole 96 extend from one end face 71a to the other end face 71b of the back yoke 71.

[0070] The B-phase second auxiliary pole 96 is adjacent to the B-phase main pole 91c around axis L. The width (angle) of the tip of the B-phase second auxiliary pole 96 around axis L is half the pole spacing α. The distance (angle) of the tip of the B-phase second auxiliary pole 96 and the teeth 93 of the B-phase main pole 91c around axis L is the same as the pole spacing α. There is an opening 73 in the back yoke 71 between the A-phase second auxiliary pole 86 and the B-phase second auxiliary pole 96.

[0071] When current is supplied to the A-phase coil 88 and the B-phase coil 98, The A-phase first auxiliary pole 85 and the A-phase main pole 81a form a magnetic circuit Ma1. The A-phase main pole 81a and the A-phase main pole 81b form a magnetic circuit Ma2. The A-phase main pole 81b and the A-phase main pole 81c form a magnetic circuit Ma3. The A-phase main pole 81c and the A-phase second auxiliary pole 86 form a magnetic circuit Ma4. The B-phase first auxiliary pole 95 and the B-phase main pole 91a form a magnetic circuit Mb1. The B-phase main pole 91a and the B-phase main pole 91b form a magnetic circuit Mb2. The B-phase main pole 91b and the B-phase main pole 91c form a magnetic circuit Mb3. The B-phase main pole 91c and the B-phase second auxiliary pole 96 form a magnetic circuit Mb4.

[0072] In the stator unit 6A, when current is supplied to the A-phase coil 88 and the B-phase coil 98 so that the rotor 30 rotates, all A-phase main poles 81 and all B-phase main poles 91 consistently form a magnetic circuit, and the same magnetic circuit is formed even when the current is switched.

[0073] Figure 14 is a cross-sectional view of a stator unit 6B according to a second modified example of the stator unit 6. Figure 15 is a schematic diagram showing the magnetic circuit formed in the stator core 70B of the stator unit 6B of Figure 14. In Figure 15, the dashed lines schematically represent the magnetic circuit.

[0074] The stator unit 6B includes a stator 60B and a cover 100. The stator 60B includes a stator core 70B, a plurality of A-phase coils 88, and a plurality of B-phase coils 98. The stator core 70B includes a back yoke 71, two A-phase pole sets 80B, and two B-phase pole sets 90B.

[0075] The A-phase pole set 80B includes an A-phase main pole 81, an A-phase first auxiliary pole 85, and an A-phase second auxiliary pole 86. The A-phase main pole 81, the A-phase first auxiliary pole 85, and the A-phase second auxiliary pole 86 protrude from the inner surface 71d of the back yoke 71 toward the axis L. The A-phase main pole 81, the A-phase first auxiliary pole 85, and the A-phase second auxiliary pole 86 extend from one end face 71a to the other end face 71b of the back yoke 71.

[0076] The A-phase first auxiliary pole 85, the A-phase main pole 81, and the A-phase second auxiliary pole 86 are arranged in this order around axis L. The distance (angle) around axis L between the tip of the A-phase first auxiliary pole 85 and the teeth 83 of the A-phase main pole 81 is the same as the magnetic pole spacing α. The distance (angle) around axis L between the tip of the A-phase second auxiliary pole 86 and the teeth 83 of the A-phase main pole 81 is the same as the magnetic pole spacing α.

[0077] The B-phase pole set 90B includes a B-phase main pole 91, a B-phase first auxiliary pole 95, and a B-phase second auxiliary pole 96. The B-phase main pole 91, the B-phase first auxiliary pole 95, and the B-phase second auxiliary pole 96 protrude from the inner surface 71d of the back yoke 71 toward the axis L. The B-phase main pole 91, the B-phase first auxiliary pole 95, and the B-phase second auxiliary pole 96 extend from one end face 71a to the other end face 71b of the back yoke 71.

[0078] The B-phase first auxiliary pole 95, the B-phase main pole 91, and the B-phase second auxiliary pole 96 are arranged in this order around axis L. The distance (angle) around axis L between the tip of the B-phase first auxiliary pole 95 and the teeth 93 of the B-phase main pole 91 is the same as the magnetic pole spacing α. The distance (angle) around axis L between the tip of the B-phase second auxiliary pole 96 and the teeth 93 of the B-phase main pole 91 is the same as the magnetic pole spacing α.

[0079] In Figure 14, the A-phase main pole 81, the A-phase first auxiliary pole 85, and the A-phase second auxiliary pole 86 that constitute the A-phase pole set 80B are enclosed by dashed lines, and the B-phase main pole 91, the B-phase first auxiliary pole 95, and the B-phase second auxiliary pole 96 that constitute the B-phase pole set 90B are enclosed by dashed lines.

[0080] The A-phase pole sets 80B and B-phase pole sets 90B are arranged alternately around axis L. The two A-phase pole sets 80B face each other across axis L. One of the two A-phase pole sets 80B has an A-phase main pole 81 on which an A-phase coil 88 wound in the forward direction is located, and the other has an A-phase main pole 81 on which an A-phase coil 88 wound in the reverse direction is located. The two B-phase pole sets 90B face each other across axis L. One of the two B-phase pole sets 90B has a B-phase main pole 91 on which a B-phase coil 98 wound in the forward direction is located, and the other has a B-phase main pole 91 on which a B-phase coil 98 wound in the reverse direction is located.

[0081] When current is supplied to the A-phase coil 88 and the B-phase coil 98, The A-phase first auxiliary pole 85 and the A-phase main pole 81 form a magnetic circuit Ma1. The A-phase second auxiliary pole 86 and the A-phase main pole 81 form a magnetic circuit Ma2. The B-phase first auxiliary pole 95 and the B-phase main pole 91 form a magnetic circuit Mb1. The B-phase second auxiliary pole 96 and the B-phase main pole 91 form a magnetic circuit Mb2.

[0082] In the stator unit 6B, when current is supplied to the A-phase coil 88 and the B-phase coil 98 so that the rotor 30 rotates, all A-phase main poles 81 and all B-phase main poles 91 consistently form a magnetic circuit, and a similar magnetic circuit is formed even when the current is switched.

[0083] A stator core 70B may have only one A-phase pole set 80B, or it may have three or more. A stator core 70B may have only one B-phase pole set 90B, or it may have three or more. The number of A-phase pole sets 80B and the number of B-phase pole sets 90B are the same.

[0084] An electric valve having stator units 6A and 6B also produces the same effects as electric valve 1.

[0085] In this specification, terms indicating shapes such as "cylinder" and "column" are also used to refer to members or parts of members that substantially have the shape of those terms. For example, "cylindrical member" includes both cylindrical members and substantially cylindrical members. Furthermore, in this specification, the term "same" may include both strictly identical and substantially identical items.

[0086] Although embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, deletions, design modifications, and combinations of features of the embodiments, as appropriate by those skilled in the art, are also included within the scope of the present invention, as long as they do not contradict the spirit of the invention. [Explanation of Symbols]

[0087] 1...Electric valve, 8...First pipeline, 9...Second pipeline, 5... Valve body assembly, 10... Valve body, 30... Rotor, 6... Stator unit, 60... Stator, 100... Cover 70... Stator core, 71... Back yoke, 72... Inner space, 73... Opening 80...A-phase pole set, 81...A-phase main pole, 85...A-phase first auxiliary pole, 86...A-phase second auxiliary pole, 88...A-phase coil, 90...B-phase pole set, 91...B-phase main pole, 95...B-phase first auxiliary pole, 96...B-phase second auxiliary pole, 98...B-phase coil L…Axis line

Claims

1. A stator used in an electric valve, The stator comprises a stator core and a coil, The stator core comprises a back yoke and a pole set, The back yoke has an inner space extending from one end face to the other end face of the back yoke, and an opening provided on the outer surface of the back yoke, extending from one end face to the other end face and communicating with the inner space. The pole set comprises a main pole on which the coil is arranged, and an auxiliary pole. The main pole and the auxiliary pole protrude from the inner surface defining the inner space in the back yoke toward the central axis of the inner space, and are adjacent to each other around the central axis. A stator characterized in that the auxiliary pole forms a magnetic circuit together with the main pole when the coil is energized.

2. A stator used in an electric valve, The stator comprises a stator core, a plurality of A-phase coils, and a plurality of B-phase coils. The stator core comprises a back yoke, an A-phase pole set, and a B-phase pole set. The back yoke has an inner space extending from one end face to the other end face of the back yoke, and an opening provided on the outer surface of the back yoke, extending from one end face to the other end face and communicating with the inner space. The aforementioned A-phase pole set comprises a plurality of A-phase main poles and an A-phase first auxiliary pole. The aforementioned B-phase pole set comprises a plurality of B-phase main poles and a B-phase first auxiliary pole. The plurality of A-phase main poles, the A-phase first auxiliary poles, the plurality of B-phase main poles, and the B-phase first auxiliary poles protrude from the inner surface defining the inner space in the back yoke toward the central axis of the inner space, The plurality of A-phase main poles are arranged around the central axis, and the A-phase first auxiliary pole is adjacent to an A-phase main pole at one end of the arrangement of the plurality of A-phase main poles around the central axis. The plurality of B-phase main poles are arranged around the central axis, and the B-phase first auxiliary pole is adjacent to a B-phase main pole at one end of the arrangement of the plurality of B-phase main poles around the central axis. The plurality of A-phase coils are arranged alternately on the plurality of A-phase main poles, and include A-phase coils wound in the forward direction and A-phase coils wound in the reverse direction. The plurality of B-phase coils are arranged alternately on the plurality of B-phase main poles, and include B-phase coils wound in the forward direction and B-phase coils wound in the reverse direction. When the plurality of A-phase coils are energized, the A-phase first auxiliary pole forms a magnetic circuit together with the A-phase main pole. When the plurality of B-phase coils are energized, the B-phase first auxiliary pole forms a magnetic circuit together with the B-phase main pole. A stator characterized in that the A-phase first auxiliary pole and the B-phase first auxiliary pole are adjacent to each other around the central axis and face the opening with the central axis in between.

3. The aforementioned A-phase pole set further comprises an A-phase second auxiliary pole, The aforementioned B-phase pole set further comprises a second B-phase auxiliary pole, The A-phase second auxiliary pole and the B-phase second auxiliary pole protrude from the inner surface toward the central axis, The A-phase second auxiliary pole is adjacent to the A-phase main pole at the other end of the row of A-phase main poles around the central axis, The B-phase second auxiliary pole is adjacent to the B-phase main pole at the other end of the row of B-phase main poles around the central axis, When the plurality of A-phase coils are energized, the A-phase second auxiliary pole forms a magnetic circuit together with the A-phase main pole. The stator according to claim 2, wherein the B-phase second auxiliary pole forms a magnetic circuit together with the B-phase main pole when the plurality of B-phase coils are energized.

4. A stator used in an electric valve, The stator comprises a stator core, an A-phase coil, and a B-phase coil. The stator core comprises a back yoke, an A-phase pole set, and a B-phase pole set. The back yoke has an inner space extending from one end face to the other end face of the back yoke, and an opening provided on the outer surface of the back yoke, extending from one end face to the other end face and communicating with the inner space. The A-phase pole set comprises an A-phase main pole on which the A-phase coil is arranged, an A-phase first auxiliary pole, and an A-phase second auxiliary pole. The B-phase pole set comprises a B-phase main pole on which the B-phase coil is arranged, a B-phase first auxiliary pole, and a B-phase second auxiliary pole. The A-phase main pole, the A-phase first auxiliary pole, the A-phase second auxiliary pole, the B-phase main pole, the B-phase first auxiliary pole, and the B-phase second auxiliary pole protrude from the inner surface defining the inner space in the back yoke toward the central axis of the inner space, The A-phase first auxiliary pole, the A-phase main pole, and the A-phase second auxiliary pole are arranged in this order around the central axis. The B-phase first auxiliary pole, the B-phase main pole, and the B-phase second auxiliary pole are arranged in this order around the central axis. When the A-phase coil is energized, the first auxiliary pole of phase A and the second auxiliary pole of phase A form a magnetic circuit together with the main pole of phase A. When the B-phase coil is energized, the B-phase first auxiliary pole and the B-phase second auxiliary pole together with the B-phase main pole form a magnetic circuit. A stator characterized in that the opening is located between the A-phase pole set and the B-phase pole set.

5. An electric valve having a stator according to claim 1, claim 2, or claim 4 and a valve body assembly, The valve body assembly, A valve body having a cylindrical shape and positioned in the inner space, It has a magnet rotor which is positioned inside the valve body and, together with the stator, constitutes a motor, An electric valve characterized in that a pipeline is connected to one end and the other end of the valve body.

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