Motor

Abstract

To improve torque at the startup.SOLUTION: A motor 1 includes a rotor 42 and a single-phase stator 2. The stator 2 has a magnetic pole part 24 opposed to the rotor 42 in the radial direction. The magnetic pole part 24 includes a plurality of magnetic bodies 21 stacked in an axial x direction of a rotating shaft 41. A fitting portion 28 is formed on a surface of two magnetic bodies 21 overlapped on each other among the plurality of magnetic bodies 21. The plurality of magnetic bodies 21 include two projections 241, 242 projecting in directions opposite to each other in the circumferential direction. In the circumferential direction, the distance from an end of one projection 241 of the two projections 241, 242 to the fitting portion 28 is longer than the distance from an end of the other projection 242 to the fitting portion 28.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a motor. [Background technology]

[0002] BACKGROUND ART A single-phase motor having a structure including a rotor with a plurality of magnetic poles and a stator with the same number of teeth as the number of magnetic poles is known (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 077716 Summary of the Invention [Problem to be solved by the invention]

[0004] In single-phase motors, in order to determine the direction of rotation at startup, some of the stator teeth are positioned away from the magnetic field generated by the magnet, so that the center of the magnet is not positioned at the center of the teeth.

[0005] However, in a single-phase motor, when the teeth are farther away from the magnet, the torque required to drive the single-phase motor may be insufficient.

[0006] The present invention addresses the above-mentioned problem as an example, and has an object to provide a motor that can improve torque at startup. [Means for solving the problem]

[0007] In order to achieve the above object, the motor of the present invention comprises a rotor and a single-phase stator, the stator having a magnetic pole portion facing the rotor in the radial direction, the magnetic pole portion comprising a plurality of magnetic bodies stacked in the direction of the rotation axis, and a fitting portion formed on the surface of two of the overlapping magnetic bodies, the plurality of magnetic bodies having two protrusions protruding in opposite directions in the circumferential direction, and the distance from the end of one of the two protrusions to the fitting portion in the circumferential direction being greater than the distance from the end of the other protrusion to the fitting portion. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically showing the configuration of a motor according to an embodiment of the present invention. [Figure 2] 2 is a cross-sectional plan view schematically showing the configuration of the motor shown in FIG. 1. FIG. [Figure 3] 2 is a plan view showing a stator core and a rotor in the motor shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A motor according to an embodiment of the present invention will now be described with reference to the drawings.

[0010] Fig. 1 is a cross-sectional view schematically showing the configuration of a motor 1 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line AA schematically showing the configuration of the motor 1. Fig. 3 is a partially enlarged plan view showing a stator core 20 and a rotor 42 in the motor 1.

[0011] 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. Furthermore, 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 motor 1. Furthermore, in the following description, for convenience, the direction of motor 1 viewed from upper side a toward lower side b will be referred to as the plane, and the direction viewed from lower side b toward upper side a will be referred to as the bottom. In other words, the cross-sectional view of FIG. 2 is a cross-sectional view of motor 1 viewed from a plane. Furthermore, in the following description, the direction around axis x will be referred to as the circumferential direction.

[0012] As shown in FIGS. 1 to 3, a motor 1 according to this embodiment includes a rotor 42 and a single-phase stator 2. The stator 2 has a magnetic pole portion 24 that faces the rotor 42 in the radial direction. The magnetic pole portion 24 includes a plurality of magnetic bodies 21 stacked in the direction of the axis x of a rotating shaft 41. A fitting portion 28 is formed on the surface of two of the magnetic bodies 21 that overlap each other. The magnetic bodies 21 include two protruding portions 241, 242 that protrude in opposite directions in the circumferential direction. Of the two protruding portions 241, 242, the distance from an end of one protruding portion 241 to the fitting portion 28 is greater than the distance from an end of the other protruding portion 242 to the fitting portion 28. The configuration and operation of the motor 1 will now be described in detail.

[0013] [Motor configuration] The motor 1 is a single-phase motor that includes, in addition to the stator 2 described above, a coil 3, a rotating shaft 41, a rotor 42, a magnet 43, 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.

[0014] 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. The stator core 20 is configured by stacking a plurality of annular thin 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 are formed in the magnetic bodies 21. In other words, the stator core 20 is formed by stacking a plurality of magnetic bodies 21, each of which forms the rings 22, branches 23, and magnetic pole portions 24. The specific configuration of the stator core 20 will be described later.

[0015] 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 corresponds to the shape of the outer periphery of the stator core 20.

[0016] 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 motor 1 and the like are mounted on the circuit board 8.

[0017] The base 9 is provided on the lower side in the axial direction of the motor 1, for example, as shown in FIGS. 1 and 2. The base 9 has, for example, a disk-like or substantially disk-like planar shape. The lower surface of the base 9 is formed flat or substantially flat, and the base 9 is used when attaching the motor 1 to an attachment target member (not shown). The stator core 20 is disposed on the upper side of the base 9. Also provided on the upper side of the base 9 is a holder 27 that holds the first bearing 5 and the second bearing 6, and the stator core 20 is fixed thereto.

[0018] The retaining portion 27 is provided on the base 9 and is a cylindrical or approximately cylindrical portion extending 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 for holding 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 to the base 9 as a separate member by an appropriate method such as insert molding.

[0019] 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. Since 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.

[0020] The rotor 42 includes a cylindrical portion 62, a disk-shaped or approximately disk-shaped top surface 63 that covers the upper side of the stator 2 in the rotational axis direction, and a hole (inner peripheral portion) 64 provided in the center of the top surface 63. The cylindrical portion 62 surrounds the stator 2. In other words, the motor 1 is an outer rotor type in which the rotor 42 is provided on the outer peripheral side of the stator 2 in the radial direction. The cylindrical portion 62 is formed in a cylindrical or approximately cylindrical shape centered on the center of the hole 64. The outer peripheral portion of the cylindrical portion 62 supports the magnet 43, and in the illustrated example, the magnet 43 is fixed to the inner peripheral surface of the outer peripheral portion of the cylindrical portion 62. Like the cylindrical portion 62, the magnet 43 is formed in a cylindrical or approximately cylindrical shape centered on the center of the hole 64. The rotor 42 is fixed to the rotating shaft 41. Specifically, one end 411 of the rotating shaft 41 in the axial direction is attached to the hole 64 of the rotor 42.

[0021] The first bearing 5 and the second bearing 6 are press-fitted and fixed to the inner circumferential surface of the hole 26. The first bearing 5 and the second bearing 6 are arranged in the hole 26 at a predetermined distance in the axial direction of the rotating shaft 41.

[0022] The first bearing 5 is one of a pair of bearings provided in the 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. In addition, 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.

[0023] The second bearing 6 is one of a pair of bearings provided in the 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. In addition, 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.

[0024] Coil spring 7 is provided radially on the outer periphery of rotating shaft 41. Coil spring 7 is also provided axially between rotor 42 and first bearing 5. One upper end of coil spring 7 contacts the surface of top surface 63 of rotor 42 facing first bearing 5, and the other lower end contacts the surface of the inner ring of first bearing 5 facing top surface 63. Coil spring 7 applies preload from top surface 63 toward the inner ring of first bearing 5.

[0025] The specific configuration of the stator core 20 will be described with reference to Fig. 3. In Fig. 3, in order to explain the shapes of the stator core 20 and the rotor 42 in the motor 1, one of the magnetic pole portions 24 provided on the magnetic body 21 constituting the stator core 20 and a branch 23 connected to the magnetic pole portion 24 are shown enlarged.

[0026] The ring 22 is a portion formed in an annular shape, for example, a circular ring 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 (see FIGS. 1 and 2) provided on the base 9 is inserted into the annular hole 221. A plurality of branches (spokes) 23 are provided on the outer circumferential portion 222 of the ring 22 radially from the axis x.

[0027] The branches 23 are portions of the stator core 20 that extend radially outward from the outer circumferential portion 222. The branches 23 are portions that connect the ring 22 and the magnetic pole portions 24. Specifically, the branches 23 extend radially from the outer circumferential portion 222 toward the rotor 42. A plurality of branches 23, for example, four in this embodiment, are provided (see FIG. 2). An insulator 25 is disposed on the surface of each of the plurality of branches 23 (see FIGS. 1 and 2). As described above, the conducting wire that constitutes the coil 3 is wound around the plurality of branches 23 via the insulators 25.

[0028] 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 the branches 23. In addition to the protruding portions 241 and 242, the magnetic pole portions 24 are formed with an outer peripheral portion 243 and a fitting portion 28.

[0029] The protruding portion 241 is a portion that extends from the branch 23 to one side in the circumferential direction, for example, in the counterclockwise direction (the direction of the arrow s) in FIG. 3. The protruding portion 242 is a portion that extends to the other side in the circumferential direction, for example, in the clockwise direction (the direction of the arrow t) in FIG. 3. In other words, the protruding portion 241 and the protruding portion 242 protrude in opposite directions in the circumferential direction. An outer peripheral portion 243 is provided on the outer peripheral side surfaces of the protruding portion 241 and the protruding portion 242.

[0030] 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. The outer circumferential portion 243 is formed in an arc shape or a substantially arc shape.

[0031] The fitting portions 28 are provided in the magnetic pole portions 24 as recesses recessed toward other magnetic pole portions 24 overlapping in the stacking direction (axial direction), or as protrusions protruding toward other magnetic pole portions 24 overlapping in the stacking direction. Other magnetic pole portions 24 overlapping in the stacking direction (axial direction) are provided with other fitting portions 28 that fit with the fitting portions 28 of the magnetic pole portions 24. The magnetic pole portions 24 overlapping in the stacking direction (axial direction) fit with each other, thereby fixing the multiple magnetic bodies 21 to each other and forming the stator core 20. Note that the fitting portions 28 may be provided as holes penetrating the magnetic pole portions 24 in the stacking direction. A pin (not shown) is inserted into the fitting portions 28 to fix the multiple stacked and overlapping magnetic bodies 21 by crimping. The stator core 20 may be configured by fixing the plurality of magnetic bodies 21 to each other by crimping the pins inserted into the fitting portions 28 .

[0032] 3, in the magnetic pole portion 24, the fitting portion 28 is provided at a position where a distance L1 from an end 241a on the counterclockwise circumferential side (the other magnetic pole portion 24 side) of one protruding portion 241 to a center 28x of the fitting portion 28 is greater than a distance L2 from an end 242a on the clockwise side of the other protruding portion 242 to the center 28x of the fitting portion 28. In other words, in the magnetic pole portion 24, the fitting portion 28 is provided closer to the end 242a of the other protruding portion 242 in the circumferential direction than to the end 241a of one protruding portion 241. Note that the radial position of the fitting portion 28 is not limited to the position shown in FIG. 3 as long as the multiple magnetic bodies 21 can be fixed by caulking.

[0033] As described above, the shape of the outer peripheral portion 243, which is the side surface on the outer peripheral side of the magnetic pole portion 24, is arc-shaped or approximately arc-shaped. The inner peripheral side surface 431 of the magnet 43 provided on the inner peripheral side of the rotor 42 is formed in a cylindrical or approximately cylindrical shape. Here, the center that defines the shape of the arc-shaped or approximately arc-shaped outer peripheral portion 243 is x1 shown in FIG. 3 , which is the same as the center that defines the shape of the inner peripheral side surface 431 of the magnet 43 that is formed in a cylindrical or approximately cylindrical shape. In other words, the rotor 42 is concentric with the magnetic pole portion 24 of the stator core 20. Note that the center x1 may coincide or approximately coincide with the axis x of the rotating shaft 41 of the motor 1.

[0034] In the radial direction of the stator core 20, a magnetic gap G is formed between the outer circumferential portion 243 of the magnetic pole portion 24 and the side surface 431 on the inner circumferential side of the magnet 43. The width (radial distance) of the magnetic gap G between the side surface 431 and the outer circumferential portion 243 of the magnetic pole portion 24 is constant in the circumferential direction from the end 241a of one protruding portion 241 to the end 242a of the other protruding portion 242.

[0035] [Motor action] Next, the operation of the motor 1 having the above-described configuration will be described.

[0036] In the motor 1, the multiple magnetic bodies 21 constituting the magnetic pole portion 24 of the stator 2 have two protrusions 241, 242 that protrude in opposite directions in the circumferential direction, and the distance L1 from the end of one protrusion 241 to the mating portion 28 is greater than the distance L2 from the end of the other protrusion 242 to the mating portion 28.

[0037] In the stator 2 of the motor 1 configured as described above, the positions of the fitting portions 28 are offset from the circumferential center of the magnetic pole portions 24, thereby creating a small magnetic resistance in the portion of the magnetic pole portion 24 where the fitting portions 28 are formed and a large magnetic resistance in the other portion of the magnetic pole portion 24, thereby changing the magnitude of the magnetic resistance in the magnetic pole portion 24. This allows the motor 1 to vary the flow of magnetic flux, thereby varying the strength of the magnetic flux directed toward the rotor from both sides (left and right) of the magnetic pole portion 24 in the circumferential direction. This changes the magnitude of the electromagnetic force (torque) acting on the magnetic pole portion 24, allowing the single-phase motor to smoothly rotate in the desired direction. Therefore, the motor 1 eliminates the torque shortage caused by the magnetic pole portion 24 being farther away from the magnet 43, thereby improving the torque required for motor operation. In particular, when the motor 1 is operated in a low-temperature environment, the viscosity of the viscous material (grease) contained in the first bearing 5, second bearing 6, etc. is low, so a torque relatively greater than that required for motor operation in a normal temperature environment may be required. Therefore, the motor can be driven smoothly while reducing the influence of the ambient temperature due to the improved torque.

[0038] Furthermore, in the motor 1, the center defining the shape of the arc-shaped or approximately arc-shaped outer periphery 243 can be the same as the center defining the shape of the inner circumferential side surface 431 of the magnet 43, which is cylindrical or approximately cylindrical. The width of the magnetic gap G between the side surface 431 and the outer periphery 243 of the magnetic pole portion 24 can be constant in the circumferential direction from the end 241a of one protrusion 241 to the end 242a of the other protrusion 242. In other words, in the motor 1, the shape of the outer periphery 243 of the magnetic pole portion 24 is the same on both sides in the rotation direction, and the rotation direction of the single-phase motor can be determined. Therefore, in the motor 1, the magnetic pole portion 24 can be positioned a predetermined distance from the magnet 43, thereby improving the torque required to drive the motor.

[0039] 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.

[0040] For example, the motor 1 described above is a single-phase outer rotor type, but the present invention can also be applied to an inner rotor type motor as long as it is a single-phase motor. [Explanation of symbols]

[0041] 1...motor, 2...stator, 3...coil, 5...first bearing, 6...second bearing, 8...circuit board, 9...base, 20...stator core, 21...magnetic material, 22...ring, 23...branch, 24...magnetic pole portion, 25...insulator, 26...hole portion, 27...retaining portion, 28...fitting portion, 28x, x1...center, 41...rotating shaft, 42...rotor, 43...magnet, 62...cylindrical portion, 63...top surface portion, 64...hole portion, 221...annular hole, 222...outer periphery, 241, 242...protruding portion, 241a, 242a...end portion, 243...outer periphery, x...axis

Claims

1. A rotor, a single-phase stator; the stator has a magnetic pole portion facing the rotor in the radial direction, the magnetic pole portion includes a plurality of magnetic bodies stacked in the direction of the rotation axis, Two of the plurality of magnetic bodies have mating portions formed on their surfaces, and The plurality of magnetic bodies each include two protruding portions that protrude in opposite directions in the circumferential direction, a motor in which the distance from an end of one of the two protrusions to the fitting portion in the circumferential direction is greater than the distance from the end of the other protrusion to the fitting portion.

2. a magnetic gap is formed between a side surface of the rotor and a side surface of the magnetic pole portion in the radial direction; the width of the magnetic gap is constant in the circumferential direction from one protruding portion to the other protruding portion; The motor according to claim 1 .

3. The center of the side surface of the rotor and the center of the side surface of the magnetic pole portion are the same.

3. The motor according to claim 1 or 2.

4. The stator includes: a ring-shaped portion and a plurality of branches connected to the ring-shaped portion and the magnetic pole portion; 3. The motor according to claim 1 or 2.

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