Single-phase motor

Abstract

The present invention is capable of easily confirming a rotation direction of a rotating component in assembly while securing a region for performing winding.　In this single-phase motor, a stator core (20) has: an annular ring (22); branches (23) extending radially outward from the ring (22); and a plurality of magnetic pole portions (24) connected to the branches (23) and aligned in the circumferential direction. The magnetic pole portion (24) has: a first surface (241) that extends from the branch (23) to one side in the circumferential direction and faces the ring (22) in the radial direction; and a second surface (242) that extends to the other side in the circumferential direction and faces the ring (22) in the radial direction. In the radial direction, the stator core (20) has a distance (L1) from the first surfaces (241) to the ring (22) and a distance (L2) from the second surface (242) to the ring (22), which are different from each other. An insulator (25) is bonded to the branch (23), the first surface (241), and the second surface (242).

Description

Single-phase motor

[0001] The present invention relates to a single-phase motor.

[0002] A single-phase motor is known in which the stator or magnet member is anisotropically configured, and the stator tip has no notch, and the length of the air gap between the stator tip and the rotor magnet is set to a constant length (see Patent Document 1).

[0003] Japanese Patent Application Publication No. 8-317619

[0004] In a single-phase motor, the stator and rotor must be eccentric in order for the rotor to rotate. Therefore, single-phase motors must be designed so that the rotation directions of rotating parts such as the stator and rotor are not mistaken during assembly. To make it easier to check the rotation directions of rotating parts, for example, a recess has been provided in the part of the stator where the windings are located.

[0005] However, in a single-phase motor, when a recess is provided in the portion of the stator where the winding is performed, the winding area is reduced because the recess cannot be used for winding. In other words, further improvement is required to reduce the power consumption of a single-phase motor when a recess is provided in the portion of the stator where the winding is performed.

[0006] The present invention addresses the above-mentioned problem as an example, and aims to provide a structure in a single-phase motor that allows the rotation direction of rotating parts to be easily confirmed during assembly while ensuring an area for winding.

[0007] In order to achieve the above object, the single-phase motor of the present invention is a single-phase motor comprising: a stator composed of a plurality of plate-shaped magnetic bodies stacked in a predetermined direction; a coil composed of a conductive wire wound around the stator; a rotating shaft arranged rotatably relative to the stator; a rotor fixed to the rotating shaft; and a magnet fixed to the rotor, wherein the stator comprises an annular ring, branches extending radially outward from the ring, a plurality of magnetic pole portions arranged circumferentially and connecting to the branches, a stator core having the magnetic pole portions, the ring, and the branches, and an insulator fixed to the stator core, wherein the magnetic pole portions have a first surface extending from the branches to one side in the circumferential direction and facing the ring in the radial direction, and a second surface extending to the other side in the circumferential direction and facing the ring in the radial direction, wherein the distance from the first surface to the ring is different from the distance from the second surface to the ring in the radial direction, and the insulator is joined to the branches, the first surface, and the second surface.

[0008] The single-phase motor according to the present invention can provide a structure that allows the rotation direction of the rotating parts to be easily confirmed during assembly while ensuring an area for winding.

[0009] 1 is a cross-sectional view schematically showing the configuration of a single-phase motor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the configuration of the single-phase motor shown in FIG. 1. FIG. 3 is a plan view showing a stator core and an insulator in the single-phase motor shown in FIG. 1. FIG. 4 is a partially enlarged plan view showing a stator core in the single-phase motor shown in FIG. 1. FIG. 5 is a partially enlarged plan view showing a first modified example of the stator core in the single-phase motor shown in FIG. 1. FIG. 6 is a partially enlarged plan view showing a second modified example of the stator core in the single-phase motor shown in FIG. 1. FIG. 7 is a partially enlarged plan view showing a third modified example of the stator core in the single-phase motor shown in FIG. 1.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A single-phase motor according to an embodiment of the present invention will be described below with reference to the drawings.

[0011] Fig. 1 is a cross-sectional view showing a schematic configuration of a single-phase motor 1 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing a schematic configuration of the single-phase motor 1.

[0012] In the following description, for convenience, the direction of arrow a in the direction of axis x will be referred to as the upper side a, and the direction of arrow b will be referred to as the lower side b. In addition, in the radial direction perpendicular to axis x, the direction away from axis x (the direction of arrow c in FIG. 1 ) will be referred to as the outer circumferential side c, and the direction toward axis x (the direction of arrow d in FIG. 1 ) will be referred to as the inner circumferential side d. In the following description, for convenience, the direction shown in FIG. 1 will be referred to as the side of the single-phase motor 1. In addition, in the following description, for convenience, the direction of the single-phase motor 1 viewed from the upper side a toward the lower side b will be referred to as the planar surface, and the direction of the single-phase motor 1 viewed from the lower side b toward the upper side a will be referred to as the bottom surface. In other words, the cross-sectional view of FIG. 2 is a cross-sectional view of the single-phase motor 1 viewed from the planar surface. In the following description, the direction around axis x will be referred to as the circumferential direction.

[0013] 1 to 3 , a single-phase motor 1 according to this embodiment includes a stator core 20 formed of a plurality of plate-shaped magnetic bodies 21 stacked in a predetermined direction, an insulator 25 fixed to the stator core, a stator 2 having a coil 3 formed by winding a conductor around the stator core 20 via the insulator 25, a rotating shaft 41 arranged rotatably relative to the stator 2, a rotor 42 fixed to the rotating shaft 41, and a magnet 43 fixed to the rotor 42. In the single-phase motor 1, the stator core 20 includes an annular ring 22, branches 23 extending radially outward from the ring 22, and a plurality of magnetic pole portions 24 arranged in a circumferential direction and connected to the branches 23. Each magnetic pole portion 24 has a first surface 241 extending from the branch 23 to one side in the circumferential direction and facing the ring 22 in the radial direction, and a second surface 242 extending to the other side in the circumferential direction and facing the ring 22 in the radial direction. In the stator core 20, the distance from the first surface 241 to the ring is different from the distance from the second surface 242 to the ring in the radial direction, and the insulator 25 is joined to the branch 23, the first surface 241, and the second surface 242. The configuration and operation of the single-phase motor 1 will be described in detail below.

[0014] [Configuration of the Single-Phase Motor] In addition to the stator 2, coil 3, rotating shaft 41, rotor 42, and magnet 43 described above, the single-phase motor 1 also includes a first bearing 5, a second bearing 6, a coil spring 7 as an elastic body, a circuit board 8 as a substrate, and a base 9.

[0015] The stator 2 is configured by stacking a plurality of plate-shaped magnetic bodies 21 in the axial direction, and includes a stator core 20, insulators 25, and coils 3. The stator 2 is fixed to a base 9. As described above, the stator core 20 is configured by stacking a plurality of annular thin-plate magnetic bodies 21, such as electromagnetic steel plates, in the axial direction, which is an example of a predetermined direction. The rings 22, branches 23, and magnetic pole portions 24 of the stator core 20 described above are formed on each of the magnetic bodies 21. In other words, the stator core 20 is formed by stacking a plurality of magnetic bodies 21, on which the rings 22, branches 23, and magnetic pole portions 24 are formed. The specific configuration of the stator core 20 will be described later.

[0016] The coil 3 is composed of a conductor wound around the stator core 20 via an insulator 25. The insulator 25 is an insulating member attached to the stator core 20. In order to attach the insulator 25 to the stator core 20, the shape of the portion of the insulator 25 that is joined to the stator core 20 (hereinafter referred to as the joint portion) has a shape that corresponds to the shape of the outer periphery of the stator core 20.

[0017] The circuit board 8 is provided between the base 9 and the stator 2 in the axial direction. Electronic components that constitute a control circuit for controlling the operation of the single-phase motor 1 and the like are mounted on the circuit board 8.

[0018] The base 9 is provided at the upper and lower ends of the single-phase motor 1 in the axial direction, for example, on the lower side as shown in FIGS. 1 and 2 . The base 9 is formed in a disk shape or a substantially disk shape in a plan view. The lower surface of the base 9 is formed to be flat or a substantially flat surface, and is used when attaching the single-phase motor 1 to an attachment target member (not shown). The stator core 20 is disposed above the base 9. Also provided above the base 9 is a holder 27 for holding the first bearing 5 and the second bearing 6, to which the stator core 20 is fixed.

[0019] The retaining portion 27 is a cylindrical or approximately cylindrical portion that is provided on the base 9 and extends upward from the base 9. A cylindrical or approximately cylindrical space is formed inside the inner periphery of the retaining portion 27, and holes 26 that retain the first bearing 5 and the second bearing 6 are formed therein. The ring 22 of the stator core 20 is disposed on the outer periphery of the retaining portion 27. The retaining portion 27 may be attached as a separate member from the base 9 by an appropriate method such as insert molding.

[0020] The rotating shaft 41 is disposed in the hole 26 of the holding portion 27. The first bearing 5 and the second bearing 6 are disposed side by side in the axial direction in the hole 26. Because the base 9 on which the holding portion 27 is provided and the stator core 20 are fixed, the first bearing 5 and the second bearing 6 support the rotating shaft 41 rotatably relative to the stator core 20.

[0021] The rotor 42 includes a cylindrical portion 62, a disk-shaped or approximately disk-shaped top surface portion 63 that covers the upper side of the stator 2 in the rotational axis direction, and a hole 64 provided in the center of the top surface portion 63. The cylindrical portion 62 surrounds the stator 2. The cylindrical portion 62 also supports a magnet 43, and in the illustrated example, the magnet 43 is fixed to the inner surface of the cylindrical portion 62. The rotor 42 is fixed to the rotating shaft 41. Specifically, one end 411 of the axial upper end of the rotating shaft 41 is attached to the hole 64 of the rotor 42.

[0022] The first bearing 5 and the second bearing 6 are press-fitted into the inner peripheral surface of the hole 26. The first bearing 5 and the second bearing 6 are arranged in the hole 26 at a predetermined distance apart in the axial direction of the rotating shaft 41.

[0023] The first bearing 5 is one of a pair of bearings provided in the single-phase motor 1 and is provided on the upper side of the rotating shaft 41. The first bearing 5 is, for example, a ball bearing including an inner ring, an outer ring, and a plurality of rolling elements provided between the inner ring and the outer ring. The inner peripheral surface of the inner ring of the first bearing 5 is attached to the outer peripheral surface of the rotating shaft 41. Furthermore, the outer peripheral surface of the outer ring of the first bearing 5 is attached to the inner peripheral surface of the hole portion 26.

[0024] The second bearing 6 is one of a pair of bearings provided in the single-phase motor 1 and is provided below the rotating shaft 41. The second bearing 6 is, for example, a ball bearing including an inner ring, an outer ring, and a plurality of rolling elements provided between the inner ring and the outer ring. The inner peripheral surface of the inner ring of the second bearing 6 is attached to the outer peripheral surface of the rotating shaft 41. Furthermore, the outer peripheral surface of the outer ring of the second bearing 6 is attached to the inner peripheral surface of the hole portion 26.

[0025] The coil spring 7 is provided radially on the outer periphery of the rotating shaft 41. The coil spring 7 is also provided axially between the rotor 42 and the first bearing 5. One upper end of the coil spring 7 contacts the surface of the top surface 63 of the rotor 42 facing the first bearing 5, and the other lower end contacts the surface of the inner ring of the first bearing 5 facing the top surface 63. The coil spring 7 applies a preload from the top surface 63 toward the inner ring of the first bearing 5.

[0026] Fig. 3 is a plan view showing the stator core 20 and the insulator 25 in the single-phase motor 1. Fig. 4 is a partially enlarged plan view showing the stator core 20 in the single-phase motor 1. The specific configuration of the stator core 20 will be described with reference to Figs. 3 and 4.

[0027] The ring 22 is a portion formed in an annular shape in the central portion of the stator core 20. The ring 22 has an annular hole 221, which is an annular hole on the inner circumferential side, and the annular hole 221 is formed by the inner surface of the ring 22. A holding portion 27 provided on the base 9 is inserted into the annular hole 221. A plurality of branches 23 are provided on the outer circumferential portion 222 of the ring 22 radially from the axis x.

[0028] The branches 23 are portions of the stator core 20 that extend radially outward from the outer periphery 222. Specifically, the branches 23 extend radially from the outer periphery 222 toward the rotor 42. A plurality of branches 23, for example, four in this embodiment, are provided. As shown in FIGS. 1 and 2 , an insulator 25 is disposed on the surface of each of the plurality of branches 23. As described above, the conducting wire that constitutes the coil 3 is wound around the plurality of branches 23 via the insulator 25 (see FIGS. 1 and 2 ).

[0029] The magnetic pole portions 24 are connected to the branches 23, that is, a plurality of magnetic pole portions 24 are arranged in the circumferential direction according to the number of branches 23. In addition to a first surface 241 and a second surface 242, the magnetic pole portions 24 are also formed with an outer circumferential portion 243.

[0030] The first surface 241 extends from the branch 23 to one side in the circumferential direction, for example, in the counterclockwise direction in FIG. 4 , and faces the outer circumferential portion 222 in the radial direction. The second surface 242 extends to the other side in the circumferential direction, for example, in the clockwise direction in FIG. 4 , and faces the outer circumferential portion 222 in the radial direction.

[0031] As shown in FIG. 4 , the magnetic pole portion 24 of the stator core 20 has a first surface 241 with a different shape than the second surface 242. Specifically, the first surface 241 and the second surface 242 have different curved shapes. Specifically, the first surface 241 and the second surface 242 have curved surfaces with different radii of curvature. Furthermore, in the magnetic pole portion 24, the shortest distance L1 from the first surface 241 to the outer periphery 222 is different from the shortest distance L2 from the second surface 242 to the outer periphery 222 in the radial direction. In the magnetic pole portion 24, the distance L1 is, for example, the distance from a connection portion 244 between the first surface 241 and the branch 23 to a connection portion 245 between the outer periphery 222 and the branch 23. Furthermore, the distance L2 is, for example, the distance from a connection portion 246 between the second surface 242 and the branch 23 to a connection portion 247 between the outer periphery 222 and the branch 23. The branch 23 , the first surface 241 , and the second surface 242 are joined to the insulator 25 .

[0032] The outer circumferential portion 243 is a portion of the magnetic pole portion 24 that faces the magnet 43 provided in the cylindrical portion 62 of the rotor 42, and the surface of the outer circumferential portion 243 facing the rotor 42 is formed in an arc shape or a substantially arc shape.

[0033] [Operation of Single-Phase Motor] Next, the operation of the single-phase motor 1 having the above-described configuration will be described.

[0034] In general, in a single-phase motor, the rotor and stator are arranged eccentrically depending on the direction of rotation of the rotor. For example, the shape of the outer periphery of the magnetic pole portion of the stator core is configured to be eccentric relative to the shape of the inner periphery of the rotor magnet. If the rotor and stator were not arranged eccentrically, the stop position of the rotor when the motor is not energized would match the position of the rotor when the motor is energized, causing the rotor magnet and the stator coil to attract each other. In this case, the rotor may not rotate even when the motor is energized. The position where the stop position of the rotor when the motor is not energized and the position of the rotor when the motor is energized match is called a dead point.

[0035] In consideration of the above circumstances, in the single-phase motor 1 described above, as shown in FIG. 4 , the first surface 241 and the second surface 242 of the magnetic pole portion 24 of the stator core 20 have different shapes. In the magnetic pole portion 24, the shortest distance L1 from the first surface 241 to the outer periphery 222 is different from the shortest distance L2 from the second surface 242 to the outer periphery 222 in the radial direction. In addition, the shape of the joint portion of the insulator 25 with the stator core 20 corresponds to the shape of the outer periphery of the stator core 20. By having such a shape, the insulator 25 is joined to the branches 23, the first surface 241, and the second surface 242.

[0036] By including the stator core 20 and insulator 25 having the shapes described above, the single-phase motor 1 can correctly assemble components such as the stator core 20 and insulator 25, which are configured to match the rotational direction of the stator 2. Furthermore, the single-phase motor 1 described above can avoid reducing the area for winding the conductor of the coil 3, as would be the case if, for example, recesses were provided in the branches 23, which are the portions for winding the conductor of the coil 3, in order to correctly assemble the components, and can prevent an increase in power consumption.

[0037] Therefore, with the single-phase motor 1 configured as described above, the direction of rotation of the rotating parts can be easily confirmed during assembly while ensuring an area for winding.

[0038] [Variant] The single-phase motor of the present invention is not limited to the shapes of the stator core 20 and insulator 25 described above, as long as the shape of the first surface and the shape of the second surface are different in the magnetic pole portion of the stator core due to the shortest radial distance from the first surface to the outer periphery being different from the shortest radial distance from the second surface to the outer periphery, and the shape of the joint portion of the insulator with the stator core has a shape that corresponds to the shape of the outer periphery of the stator core.

[0039] FIG. 5 is a partially enlarged plan view showing a stator core 20A of the single-phase motor 1 according to the first modification.

[0040] For example, in the single-phase motor 1, as in the stator core 20A of variant example 1 shown in Figure 5, the first surface 241A and the second surface 242A may be formed by flat surfaces extending in the tangential direction of the outer peripheral portion 222, which is the outer peripheral surface formed in an annular shape of the ring 22, so that the shapes of the first surface 241A and the second surface 242A may be different.

[0041] 6 is a partially enlarged plan view showing a stator core 20B according to a second modification of the single-phase motor 1. For example, the single-phase motor 1 may have a recess 248B in the second surface 242B, so that the shapes of the first surface 241 and the second surface 242B are different. Note that the recess 248B may be provided in the first surface 241.

[0042] 7 is a partially enlarged plan view showing a stator core 20C according to a third modification of the single-phase motor 1. For example, in the single-phase motor 1, the first surface 241C and the second surface 242C may be configured with a flat surface 249C and curved surfaces 250C, 251C that are continuous with the flat surface 249C and have different radii of curvature for the first surface 241C and the second surface 242C, so that the shapes of the first surface 241C and the second surface 242C may be different.

[0043] In addition, those skilled in the art can appropriately modify the present invention in accordance with conventionally known knowledge. As long as such modifications still comprise the structure of the present invention, they are of course included in the scope of the present invention.

[0044] 1... Single-phase motor, 2... Stator, 3... Coil, 5... First bearing, 6... Second bearing, 8... Circuit board, 9... Base, 20, 20A, 20B, 20C... Stator core, 21... Magnetic material, 22... Ring, 23... Branch, 24... Magnetic pole portion, 25... Insulator, 26... Hole portion, 27... Holding portion, 41... Rotating shaft, 42... Rotor, 43... Magnet, 62... Cylindrical portion, 63...top surface portion, 64...hole portion, 221...annular hole, 222...outer periphery portion, 241, 241A, 241C...first surface, 242, 242A, 242B, 242C...second surface, 243...outer periphery portion, 244, 245, 246, 247...connecting portion, 248B...recess portion, 249C...flat surface, 250C, 251C...curved surface, 411...one end portion, 431...inner periphery surface

Claims

1. A single-phase motor comprising: a stator having a stator core, an insulator, and a coil with a conductor wound around the stator core via the insulator; a rotating shaft; and a rotor; wherein the stator core has an annular ring, a plurality of branches extending radially from the annular ring, and a plurality of magnetic pole portions connected to the plurality of branches; each of the magnetic pole portions has a first surface extending from the branches to one side in the circumferential direction and a second surface extending to the other side in the circumferential direction; the first surface and the second surface face the annular ring in the radial direction; the distance from the first surface to the ring and the distance from the second surface to the ring are different in the radial direction; and the insulator covers the branches, the first surface, and the second surface.

2. The single-phase motor according to claim 1, wherein the first surface and the second surface have different curved surfaces.

3. The single-phase motor according to claim 2, wherein said first surface and said second surface have different radii of curvature.

4. The single-phase motor according to claim 1, wherein the first surface and the second surface comprise flat surfaces, and the flat surfaces extend in a tangential direction to the outer peripheral surface of the ring.

5. The single-phase motor according to claim 1, wherein one of the first surface and the second surface has a recess.

6. The single-phase motor according to claim 1, wherein the first surface and the second surface comprise a flat surface and a curved surface that is continuous with the flat surface.

7. The single-phase motor according to claim 6, wherein the flat surface extends in a tangential direction to the outer peripheral surface of the ring, and the curved surface of the first surface and the curved surface of the second surface have different radii of curvature.

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