Stator and motor

Abstract

This stator includes: a stator core having an annular core back part centered on an axis and a plurality of teeth extending radially from the core back part; an electrically insulating insulator having tooth tip covering parts covering tip sections of the teeth and a tooth body covering part covering the remainder of the teeth other than the tip sections; and a coil wound on the tooth body covering part of the insulator. The tooth tip covering parts have circumferential end covering sections covering circumferential end sections of the stator core at the tip sections of the teeth and tip surface covering sections covering at least portions of tip surfaces at the tip sections of the teeth. The radial thickness of the stator core at the circumferential end covering sections is larger than the radial thickness of the tip surface covering sections.

Description

Stator and motor

[0001] The present invention relates to a stator and a motor. This application claims priority based on Japanese Patent Application No. 2024-206706 filed in Japan on November 27, 2024, the content of which is incorporated herein by reference.

[0002] There is known a stator in which teeth of a stator core are covered by an insulator. For example, Patent Document 1 discloses a stator having a stator core composed of a yoke portion and a tooth portion. In the stator, a molded body made of an insulating resin is adhered to the surface of the tooth portion of the stator core.

[0003] In Patent Document 1, the molded body includes a winding winding portion that adheres to the side peripheral surface of the tooth portion, guides the winding conductor to the winding winding portion when the winding conductor is wound, and a tooth core tip side winding frame portion and a yoke core fastening portion side winding frame portion that hold the unit winding mounted on the winding winding portion. Patent Document 1 discloses that the thickness of the tooth core tip side winding frame portion and the yoke core fastening portion side winding frame portion is larger than the thickness of the winding winding portion, so that the strength of the molded body as a winding bobbin can be maintained.

[0004] Japanese Unexamined Patent Application Publication No. 2004-208386

[0005] In the configuration of Patent Document 1, in order to maintain the strength of the molded body, a tooth core tip side winding frame portion having a large thickness is located on the yoke portion side of the tip portion of the tooth portion. Therefore, in the configuration of Patent Document 1, compared with a configuration in which the thickness of the tooth core tip side winding frame portion is small or the molded body does not have the tooth core tip side winding frame portion, the number of turns of the coil that can be wound around the tooth portion is small. Therefore, in a stator in which teeth are covered by an insulator, a configuration that allows more coils to be wound around the teeth is required.

[0006] An object of the present invention is to provide a configuration that allows more coils to be wound around teeth in a stator in which the teeth are covered by an insulator.

[0007] A stator according to an exemplary embodiment of the present invention comprises a stator core having an annular core back portion centered on an axis and a plurality of teeth extending radially from the core back portion, an insulator having an electrically insulating property having a tooth tip covering portion that covers the tip portions of the teeth and a tooth body covering portion that covers the parts of the teeth other than the tip portions, and a coil wound on the tooth body covering portion of the insulator. The tooth tip covering portion has a circumferential end covering portion that covers the circumferential end of the stator core at the tip of the tooth and a tip surface covering portion that covers at least a part of the tip surface at the tip of the tooth. The radial thickness of the stator core in the circumferential end covering portion is greater than the radial thickness of the tip surface covering portion.

[0008] A motor according to an exemplary embodiment of the present invention comprises a stator and a rotor rotatable about the axis of the stator.

[0009] According to the present invention, in a stator in which teeth are covered by an insulator, a configuration is provided that allows more coils to be wound around the teeth.

[0010] Figure 1 is a cross-sectional view showing an example of the schematic configuration of a motor according to an embodiment. Figure 2 is a diagram showing the inside of the motor as viewed in the axial direction. Figure 3 is a diagram showing an example of the schematic configuration of the stator as viewed in the axial direction. Figure 4 is a partial perspective view of the stator. Figure 5 is a partial perspective view of the stator in the area where the rotational position detection unit is located. Figure 6 is a diagram showing an example of the stator core as viewed in the axial direction. Figure 7 is a partial perspective view of the stator with the coils removed. Figure 8 is a view of the stator in the axial direction with the coils removed. Figure 9 is a cross-sectional view taken along the line IX-IX in Figure 8. Figure 10 is a cross-sectional view taken along the line X-X in Figure 8. Figure 11 is a cross-sectional view taken along the line XI-XI in Figure 8. Figure 12 is a view of the stator in the axial direction in the area where the rotational position detection unit is located. Figure 13 is a view of the part shown in Figure 12 from the radially outward direction. Figure 14 is a cross-sectional view taken along the line XIV-XIV in Figure 12. Figure 15 is a view of a stator according to another embodiment as viewed in the axial direction.

[0011] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. Note that identical or corresponding parts in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components or their dimensional ratios.

[0012] In the following description, the direction in which the central axis P of the motor 100 extends is referred to as "axial direction A". The circumferential direction centered on the central axis P is referred to as "circumferential direction C", and the radial direction centered on the central axis P is referred to as "radial direction R". Furthermore, the direction described as "radial outward" in the specification is shown as "R1" in the figures, and the direction described as "radial inward" is shown as "R2" in the figures. Note that the directions shown in the figures are defined solely for the convenience of explanation and do not limit the orientation of the motor during use or assembly according to the present invention.

[0013] Furthermore, in the following explanation, the expressions "fix," "connect," and "attach" (hereinafter referred to as "fixing, etc.") include not only cases where components are directly fixed to each other, but also cases where they are fixed to each other via other components. In other words, in the following explanation, the expressions "fixing, etc." include both direct and indirect fixing of components to each other.

[0014] (Motor) Figure 1 is a cross-sectional view showing an example of the schematic configuration of the motor 100. Figure 2 is a view of the inside of the motor 100 in the axial direction A. As shown in Figures 1 and 2, the motor 100 has a fixed shaft 2, a stator 3, a rotor 4, and a plurality of bearings 5. The motor 100 is applied to, for example, an in-wheel motor that is placed in the drive wheel of an electric motorcycle. In this embodiment, the case in which the motor 100 is a so-called outer rotor type motor in which the rotor 4 is located radially outward R1 of the stator 3 will be described as an example.

[0015] The fixed shaft 2 is a hollow cylindrical shape extending in the axial direction A with respect to the central axis P. The stator 3 and multiple bearings 5 ​​are fixed to the outer surface of the fixed shaft 2.

[0016] The stator 3 is the armature of the motor 100. A detailed explanation of the stator 3 will be given later.

[0017] In this embodiment, the rotor 4 is located radially outward R1 relative to the stator 3. The rotor 4 is rotatably supported on the fixed shaft 2 via a plurality of bearings 5. The rotor 4 rotates about its central axis P due to the torque in the circumferential direction C generated by the supply of drive current to the stator 3.

[0018] In this embodiment, the rotor 4 includes a rotor core 41, a magnet 42, and a holding member 43. The rotor core 41 is annular in shape, extending in the axial direction A with respect to a central axis P. The magnet 42 is fixed to the inner circumferential surface of the rotor core 41. The magnet 42 faces the stator 3 in the radial direction R.

[0019] In this embodiment, the retaining member 43 is located radially outward R1 of the rotor core 41 and holds the rotor core 41. A rim, for example, to which a tire is attached, is fixed to the outer circumference of the retaining member 43.

[0020] (Stator) Figure 3 is a diagram showing an example of the schematic configuration of the stator 3 as viewed in the axial direction A. The stator 3 includes a stator core 31, a coil 32, an insulator 33, a rotational position detection unit 35, and a support unit 36. Figure 4 is a partial perspective view of the stator 3. Figure 5 is a partial perspective view of the stator 3 in the area where the rotational position detection unit 35 is located.

[0021] (Stator Core) The stator core 31 is a magnetic material. The stator core 31 is constructed by laminating, for example, electrical steel sheets.

[0022] Figure 6 shows an example of a stator core 31 as viewed in the axial direction A. The stator core 31 has a cylindrical core back portion 311 and a plurality of teeth 312. The stator core 31 has a plurality of fastening member insertion holes 31a that penetrate in the axial direction A.

[0023] As shown in Figures 1 and 2, the inner circumferential surface of the stator core 31 is in contact with the outer circumferential surface of the fixed shaft 2. A fastening member F is inserted into each of the multiple fastening member insertion holes 31a. The stator core 31 is fixed to the fixed shaft 2 by the fastening members F inserted into the fastening member insertion holes 31a.

[0024] As shown in Figure 6, in this embodiment, the core back portion 311 is located on the inner circumference side of the stator core 31. Multiple teeth 312 extend radially outward R1 from the core back portion 311 and are arranged in the circumferential direction C.

[0025] Each tooth 312 has a main body portion 315 extending radially outward R1 from the core back portion 311, and a tip portion 316 located radially outward R1. In this embodiment, the tip surface 316a of the tooth 312 is arc-shaped when viewed in the axial direction A.

[0026] As shown in Figure 3, some of the multiple teeth 312a are positioned to overlap with the rotational position detection unit 35 when viewed in the axial direction A. As shown in Figure 6, the teeth 312a that are positioned to overlap with the rotational position detection unit 35 have an insertion hole 316b on the end face in the axial direction A of the tip portion 316. The fixed projection 363 of the support portion 36, which will be described later, is inserted into the insertion hole 316b.

[0027] Figure 7 is a partial perspective view of the stator 3 with the coil 32 removed. As shown in Figures 3, 4, and 7, the teeth 312 are covered by insulators 33 except for certain portions. The coil 32 is wound around multiple teeth 312 via the insulators 33.

[0028] (Coil) As shown in Figure 4, the coil 32 is wound around each of the teeth 312 to which the insulator 33 is attached. The insulator 33 insulates the coil 32 from the stator core 31. The coil 32 is electrically connected to an external device via lead wires.

[0029] When a drive current is supplied to the coil 32 from an external device, a radial magnetic flux is generated in the teeth 312. This generates a circumferential torque in the rotor 4, which has magnets 42, causing the rotor 4 to rotate around the central axis P.

[0030] (Insulator) The insulator 33 is an electrically insulating component. The insulator 33 is a resin molded part made of resin material. In this embodiment, the insulator 33 is integrally molded with the teeth 312 by insert molding.

[0031] Figure 8 is a view of the stator 3 with the coil 32 removed, as seen in the axial direction A. Figure 9 is a cross-sectional view taken along the line IX-IX in Figure 8. Figure 10 is a cross-sectional view taken along the line X-X in Figure 8. Figure 11 is a cross-sectional view taken along the line XI-XI in Figure 8.

[0032] The insulator 33 has a tooth body covering portion 331, a tooth tip covering portion 332, and a wall portion 333.

[0033] The tooth body covering portion 331 covers the outer circumferential surface of the main body portion 315 of the tooth 312. More specifically, the tooth body covering portion 331 covers the circumferential end face C and the axial end face A of the main body portion 315 of the tooth 312. The coil 32 is wound on the tooth body covering portion 331.

[0034] As shown in Figure 9, the thickness of the tooth body covering portion 331 is constant in the radial direction R. That is, the axial height A on the tip end 316 side of the tooth 312 in the tooth body covering portion 331 is the same as the axial height A on the base end side of the tooth 312 in the tooth body covering portion 331.

[0035] As a result, compared to the case where a wall for holding the coil is located on the tip side of the tooth body covering, the absence of the wall allows for more winding of the coil 32 on the tooth body covering 331. Therefore, the amount of winding in the coil 32 can be increased.

[0036] As shown in Figures 7, 8, and 11, the tooth tip covering portion 332 covers the tip portion 316 of the tooth 312. More specifically, the tooth tip covering portion 332 has a circumferential end covering portion 332a and a tip surface covering portion 332b.

[0037] The circumferential end covering portion 332a covers the circumferential end portion C of the tip portion 316 of the tooth 312. The tip surface covering portion 332b covers at least a portion of the tip surface 316a in the radial direction R. That is, the tooth tip covering portion 332 covers the circumferential end portion C of the tip portion 316 of the tooth 312 and at least a portion of the tip surface 316a in the radial direction R. On the other hand, in this embodiment, the tooth tip covering portion 332 does not cover the axial end surface A of the tip portion 316 of the tooth 312. That is, in this embodiment, both end surfaces in the axial direction A of the tip portion 316 of the tooth 312 are exposed.

[0038] Furthermore, at least one of the axial end faces at the tip of the tooth may be exposed. In other words, the tooth tip covering portion may cover one of the axial end faces A at the tip of the tooth.

[0039] This allows the exposed axial end face A of the tooth 312 to be used as a reference when forming the insulator 33 that covers the tooth 312 by insert molding. Therefore, the insulator 33 can be easily formed by insert molding.

[0040] As shown in Figure 8, the radial R surface of the tip surface covering portion 332b is arc-shaped when viewed in the axial direction A. As described above, the tip surface 316a of the tooth 312 is also arc-shaped when viewed in the axial direction A. When viewed in the axial direction A, the radius of curvature of the tip surface 316a of the tooth 312 is smaller than the radius of curvature of the tip surface covering portion 332b. Therefore, the radial R thickness of the tip surface covering portion 332b increases towards the end in the circumferential direction C.

[0041] This reduces the radius of curvature of the tip surface 316a of the teeth 312, thereby suppressing the generation of cogging torque. Furthermore, it allows the thickness of the circumferential end covering portion 332a of the insulator 33 in the radial direction R to be greater than the thickness of the tip surface covering portion 332b in the radial direction R, thereby improving the holding force of the coil 32 wound around the teeth 312. Thus, it is possible to achieve both the suppression of cogging torque and the improvement of the holding force of the coil 32 wound around the teeth 312.

[0042] As shown in FIG. 7, the portion located at the outermost radial position R1 on the tip surface 316a of the tooth 312 is exposed. In the present embodiment, the portion located at the outermost radial position R1 on the tip surface 316a of the tooth 312 is the circumferential central portion of the tip surface 316a of the tooth 312.

[0043] As described above, the circumferential end covering portion 332a is located in the circumferential direction C with respect to the tip portion 316 of the tooth 312. Therefore, the thickness in the radial direction R of the circumferential end covering portion 332a is larger than the thickness in the radial direction R of the tip surface covering portion 332b.

[0044] Thereby, the rigidity of the circumferential end covering portion 332a that covers the end portion in the circumferential direction C at the tip portion 316 of the tooth 312 can be ensured. Thus, even if more coils 32 are wound on the tooth main body covering portion 331 that covers portions other than the tip portion 316 of the tooth 312, the coil 32 can be held by the tooth tip covering portion 332.

[0045] As shown in FIG. 9, the wall portion 333 extends in the axial direction A from the end portion on the inner radial side R2 of the tooth main body covering portion 331. When viewed in the axial direction A, the wall portion 333 overlaps with the outer radial side R1 of the core back portion 311. The wall portion 333 insulates the coil 32 wound on the tooth main body covering portion 331 from the core back portion 311.

[0046] (Rotation position detection portion and support portion) The rotation position detection portion 35 detects the rotation position of the rotor 4. The rotation position detection portion 35 has, for example, a circuit board 351 and a hall sensor 352. The rotation position detection portion 35 is supported by the support portion 36 with respect to the stator core 31.

[0047] As shown in FIG. 5, in the present embodiment, the circuit board 351 is located in the axial direction A of the stator core 31. The circuit board 351 extends in an arc shape at a position overlapping with the outer peripheral side of the stator core 31 when viewed in the axial direction A. The hall sensor 352 is electrically connected to the circuit board 351 and is located between the teeth 312a that extend from the circuit board 351 toward the stator core 31 and are adjacent to each other in the circumferential direction C.

[0048] FIG. 12 is a view of the stator 3 in the axial direction A of the portion where the rotational position detection unit 35 is located. In FIG. 12, for the sake of explanation, the rotational position detection unit 35 and the support unit 36 are shown by a two-dot chain line. FIG. 13 is a view of the portion shown in FIG. 12 as seen from the radially outer side R1. FIG. 14 is a cross-sectional view taken along line XIV-XIV of FIG. 12.

[0049] As shown in FIGS. 5, 13, and 14, the support unit 36 has a main body portion 361, a protruding portion 362, and a fixed protruding portion 363. The main body portion 361 is located in the axial direction A of the stator core 31 and extends in the circumferential direction C at a position overlapping the tip portion 316 of the teeth 312a of the stator core 31 when viewed in the axial direction A. The main body portion 361 supports the rotational position detection unit 35.

[0050] The protruding portion 362 protrudes in the axial direction A from the side of the stator core 31 of the main body portion 361 toward the tip portion 316 of the teeth 312a. The protruding portion 362 is in contact with the end face in the axial direction A of the teeth 312a. Thereby, the main body portion 361 is axially positioned with respect to the stator core 31. Thus, the rotational position detection unit 35 is positioned at a predetermined position in the axial direction A with respect to the stator core 31.

[0051] The fixed protruding portion 363 protrudes from the side of the stator core 31 of the main body portion 361 toward the tip portion 316 of the teeth 312a. As shown in FIG. 14, the fixed protruding portion 363 is inserted into an insertion hole portion 316b located at the tip portion 316 of the teeth 312a. Thereby, the support unit 36 is fixed to the stator core 31. Thus, the rotational position detection unit 35 is positioned with respect to the stator core 31.

[0052] That is, in the present embodiment, the stator 3 has a rotational position detection unit 35 that detects the rotational position of the rotor 4 and a support unit 36 that supports the rotational position detection unit 35 with respect to the stator core 31. The support unit 36 has a protruding portion 362 that protrudes in the axial direction A from the side of the stator core 31 toward the tip portion 316 of the teeth 312a and contacts the end face in the axial direction A that is exposed at the tip portion 316 of the teeth 312a to axially position the rotational position detection unit 35 with respect to the stator core 31.

[0053] This allows the rotation position detection unit 35, which detects the rotational position of the rotor 4, to be positioned in the axial direction A relative to the stator 3. Therefore, the rotation position detection unit 35 can be positioned at a predetermined position in the axial direction A relative to the rotor 4. Consequently, the rotation of the rotor 4 can be accurately detected by the rotation position detection unit 35.

[0054] Furthermore, the support portion 36 has a fixed projection 363 that protrudes from the stator core 31 side toward the tip portion 316 of the tooth 312a. The tip portion 316 of the tooth 312a has an insertion hole portion 316b into the exposed axial end face A into which the fixed projection 363 is inserted and fixed.

[0055] This allows the support portion 36 to be fixed to the axial end face A that is exposed at the tip portion 316 of the teeth 312a. Therefore, the rotational position detection unit 35 supported by the support portion 36 can be positioned with high accuracy. Consequently, the rotation of the rotor 4 can be detected with high accuracy by the rotational position detection unit 35.

[0056] The exemplary stator 3 described above is a stator 3 having a stator core 31 having an annular core back portion 311 centered on an axis and a plurality of teeth 312 extending radially R from the core back portion 311, a tooth tip covering portion 332 that covers the tip portions 316 of the teeth 312, a tooth body covering portion 331 that covers the teeth 312 other than the tip portions 316, an electrically insulating insulator 33 and a coil 32 wound on the tooth body covering portion 331 of the insulator 33. The tooth tip covering portion 332 has a circumferential end covering portion 332a that covers the circumferential C end of the stator core 31 at the tip portion 316 of the teeth 312 and a tip surface covering portion 332b that covers at least a part of the tip surface 316a at the tip portion 316 of the teeth 312. The thickness of the stator core 31 in the radial radius R at the circumferential end covering portion 332a is greater than the thickness of the radial radius R at the tip surface covering portion 332b.

[0057] This ensures the rigidity of the circumferential end covering portion 332a of the tooth tip covering portion 332 that covers the tip portion 316 of the tooth 312 of the insulator 33, which covers the circumferential end portion C of the stator core 31 at the tip portion 316 of the tooth 312. Therefore, even if more coils 32 are wound on the tooth body covering portion 331 that covers the parts other than the tip portion 316 of the tooth 312, the coils 32 can be held by the tooth tip covering portion 332 of the insulator 33. Thus, a configuration that allows winding of more coils 32 can be realized.

[0058] In this embodiment, when the stator 3 is viewed in the axial direction A, the tip surface 316a of the teeth 312 and the tip surface covering portion 332b of the insulator 33 are, at least partially, arc-shaped. When the stator 3 is viewed in the axial direction A, the radius of curvature of the arc-shaped portion of the tip surface 316a of the teeth 312 is smaller than the radius of curvature of the arc-shaped portion of the tip surface covering portion 332b of the insulator 33.

[0059] This reduces the radius of curvature of the tip surface 316a of the teeth 312, thereby suppressing the generation of cogging torque. Furthermore, it allows the thickness of the circumferential end covering portion 332a of the insulator 33 in the radial direction R to be greater than the thickness of the tip surface covering portion 332b in the radial direction R, thereby improving the holding force of the coil 32 wound around the teeth 312. Thus, it is possible to achieve both the suppression of cogging torque and the improvement of the holding force of the coil 32 wound around the teeth 312.

[0060] In this embodiment, the portion of the tip surface 316a of the tooth 312 that is located furthest from the core back portion 311 in the radial direction R is exposed.

[0061] The portion of the tooth 312's tip surface 316a that is furthest from the core back portion 311 in the radial direction R is located closest to the rotor 4. Therefore, if this portion furthest from the core back portion 311 in the radial direction R is covered by the insulator 33, the teeth and rotor will be separated by the thickness of the insulator, affecting the magnetic characteristics of the motor.

[0062] In contrast, by exposing the portion located at the outermost radially outward R1 as in the above configuration, the thickness of the tip surface covering portion 332b of the insulator 33 that covers the tip surface 316a of the teeth 312 prevents the distance between the teeth 312 and the rotor 4 from increasing. In other words, the teeth 312 and the rotor 4 can be brought closer together, and the deterioration of the magnetic characteristics of the motor 100 can be suppressed.

[0063] In this embodiment, the portion of the tip surface 316a of the tooth 312 that is located furthest from the core back portion 311 in the radial direction R is the circumferential central portion of the tip surface 316a of the tooth 312.

[0064] This allows the tooth tip covering portion 332 of the insulator 33 to cover all but the central circumferential portion of the tip portion 316 of the tooth 312. Therefore, it is possible to prevent the tooth tip covering portion 332 from coming off the tip portion 316 of the tooth 312.

[0065] Furthermore, the motor 100 includes a stator 3 having the above-described configuration and a rotor 4 that can rotate around the axis of the stator 3. This makes it possible to realize a motor 100 having a stator 3 with the above-described configuration.

[0066] (Other Embodiments) Although embodiments of the present invention have been described above, the embodiments described above are merely examples for carrying out the present invention. Therefore, the invention is not limited to the embodiments described above, and it is possible to carry out the invention by appropriately modifying the embodiments described above without departing from the spirit of the invention.

[0067] In the above embodiment, an in-wheel motor positioned within the drive wheel of an electric motorcycle was described as an example of application of the motor 100. However, the motor of this embodiment may be applied to other configurations as long as an outer rotor motor can be applied to them.

[0068] In the above embodiment, the motor 100 was described as a so-called outer rotor type motor in which the rotor 4 is located radially outward R1 of the stator 3. However, the motor may also be a so-called inner rotor type motor in which the rotor is located radially inward of the stator. In this case, the teeth extend radially inward from the core back portion. The tips of the teeth are located on the inner circumference side of the stator core.

[0069] In the above embodiment, the portion of the tip surface 316a of the tooth 312 that is located furthest from the core back portion 311 in the radial direction R is exposed. However, the entire tip surface of the tooth may be covered by an insulator.

[0070] In the above embodiment, the portion of the tip surface 316a of the tooth 312 that is located furthest from the core back portion 311 in the radial direction R is the circumferential central portion of the tip surface 316a of the tooth 312. However, the portion of the tip surface of the tooth that is located furthest from the core back portion in the radial direction may be other than the circumferential central portion of the tip surface of the tooth.

[0071] In the above embodiment, the tip surface 316a of the tooth 312 is arc-shaped when viewed in the axial direction A. The radial surface R of the tip surface covering portion 332b is arc-shaped when viewed in the axial direction A. However, the tip surface of the tooth does not have to be arc-shaped when viewed in the axial direction. The radial surface of the tip surface covering portion does not have to be arc-shaped when viewed in the axial direction. That is, in the insulator, if the radial thickness of the circumferential end covering portion is greater than the radial thickness of the tip surface covering portion, for example, the tip surface of the tooth may have a shape composed of multiple straight lines when viewed in the axial direction. The radial surface of the tip surface covering portion may have a shape composed of multiple straight lines when viewed in the axial direction.

[0072] Furthermore, the tip surface of the tooth does not necessarily have to be arc-shaped when viewed in the axial direction. The radial surface of the tip surface covering does not necessarily have to be arc-shaped when viewed in the axial direction.

[0073] For example, as shown in Figure 15, the tip surface 1316a of the teeth 1312 in the stator core 131 of the stator 103 may be composed of an arc-shaped portion 1316c located in the circumferential central part of the teeth 1312 when viewed in the axial direction A, and a straight portion 1316d that is located toward the core back portion 311 as it approaches the end in the circumferential direction C. The tip surface covering portion 1332b of the insulator 133 may be composed of an arc-shaped portion 1332c located on the circumferential central side of the teeth 1312 when viewed in the axial direction A, and a straight portion 1332d located on the circumferential end side of the teeth 1312, which is located toward the core back portion 311 as it approaches the end in the circumferential direction C.

[0074] In other words, when viewing the stator 103 in the axial direction A, the tip surface 1316a of the teeth 1312 and the tip surface covering portion 1332b of the insulator 133 may each have an arc shape in the circumferential central portion and a linear shape at the circumferential end that is located towards the core back portion 311 as it approaches the end of the circumferential direction C.

[0075] With this configuration, the radial radius thickness of the circumferential end covering portion 332a of the insulator 133 can be made greater than the radial radius thickness of the tip surface covering portion 1332b, thereby improving the holding force of the coil 32 wound around the teeth 1312.

[0076] In the above embodiment, the insulator 33 has a wall portion 333 that extends in the axial direction A, at a position that overlaps with the core back portion 311 when viewed in the axial direction A. However, the insulator does not have to have a wall portion.

[0077] In the above embodiment, the tooth tip covering portion 332 does not cover the axial end face A of the tip portion 316 of the tooth 312. However, the tooth tip covering portion may cover both axial end faces of the tip portion of the tooth.

[0078] In the above embodiment, the stator 3 has a rotational position detection unit 35 and a support unit 36. However, the stator does not necessarily have to have a rotational position detection unit and a support unit.

[0079] In the above embodiment, the rotation position detection unit 35 includes a circuit board 351 and a Hall sensor 352. However, the configuration of the rotation position detection unit is not limited to this. The rotation position detection unit may have any other configuration as long as it can detect the rotation position of the rotor.

[0080] In the above embodiment, the support portion 36 has a fixed projection portion 363, and the tip portion 316 of the teeth 312 has an insertion hole portion 316b into the axial end face A into which the fixed projection portion 363 is inserted and fixed. However, the fixing structure of the support portion to the stator core is not limited to this. The support portion may have other configurations as long as it can position the rotational position detection unit supported by the support portion at a predetermined position relative to the stator core.

[0081] (Example Configuration) This technology can also be configured as follows:

[0082] (1) The stator is an electrically insulating insulator having an annular core back portion centered on an axis and a plurality of teeth extending radially from the core back portion, a tooth tip covering portion that covers the tip of the teeth and a tooth body covering portion that covers the teeth other than the tip, and a coil wound on the tooth body covering portion of the insulator. The tooth tip covering portion has a circumferential end covering portion that covers the circumferential end of the stator core at the tip of the tooth and a tip surface covering portion that covers at least a part of the tip surface at the tip of the tooth. The radial thickness of the stator core in the circumferential end covering portion is greater than the radial thickness of the tip surface covering portion.

[0083] (2) In the stator described in (1), when the stator is viewed in the axial direction, the tip surfaces of the teeth and the tip surface covering portion of the insulator are, at least in part, arc-shaped. When the stator is viewed in the axial direction, the radius of curvature of the arc-shaped portion of the tip surface of the teeth is smaller than the radius of curvature of the arc-shaped portion of the tip surface covering portion of the insulator.

[0084] (3) In the stator described in (2), when the stator is viewed in the axial direction, the tip surface of the teeth and the tip surface covering portion of the insulator are, in each case, arc-shaped in the central part in the circumferential direction, and the circumferential end is straight, with the circumferential end being located closer to the core back portion as it approaches the circumferential end.

[0085] (4) In the stator described in (2) or (3), the portion of the tip surface of the teeth that is located radially away from the core back portion is exposed.

[0086] (5) In the stator described in (4), the portion of the tip surface of the teeth that is located radially away from the core back portion is the circumferential central portion of the tip surface of the teeth.

[0087] (6) In the stator described in any one of (1) to (5), at least one of the axial end faces at the tip of the teeth is exposed.

[0088] (7) In the stator described in any one of (1) to (6), the axial height of the tip end of the tooth in the tooth body covering portion is the same as the axial height of the base end of the tooth in the tooth body covering portion.

[0089] (8) In the stator described in (6), the stator includes a rotation position detection unit for detecting the rotation position of the rotor and a support unit for supporting the rotation position detection unit with respect to the stator core. The support unit has a projection that protrudes axially from its stator core side toward the tip of the teeth and contacts the axial end face exposed at the tip of the teeth to position the rotation position detection unit axially with respect to the stator core.

[0090] (9) In the stator described in (8), the support portion has a fixed projection that protrudes from the stator core side toward the tip of the teeth. The tip of the teeth has an insertion hole in the exposed axial end face into which the fixed projection is inserted and fixed.

[0091] (10) The motor comprises a stator as described in any one of (1) to (9), and a rotor that is rotatable about the axis of the stator.

[0092] The configuration of the present invention is applicable to a stator in which the teeth are covered by an insulator.

[0093] 2 Fixed shaft 3, 103 Stator 4 Rotor 5 Bearing 31, 131 Stator core 31a Fastening member insertion hole 32 Coil 33, 133 Insulator 35 Rotation position detection unit 36 ​​Support unit 41 Rotor core 42 Magnet 43 Holding member 100 Motor 311 Core back unit 312, 312a, 1312 Teeth 315 Main body unit 316 Tip unit 316a, 1316a Tip surface 316b Insertion hole unit 331 Teeth main body covering unit 332 Teeth tip covering unit 332a Circumferential end covering unit 332b, 1332b Tip surface covering unit 333 Wall unit 351 Circuit board 352 Hall sensor 361 Main body unit 362 Protruding unit 363 Fixed protruding unit 1316c Arc section 1316d Straight section 1332c Arc section 1332d Straight section F Fastening member P Central axis

Claims

1. A stator comprising: a stator core having an annular core back portion centered on an axis and a plurality of teeth extending radially from the core back portion; an insulator having an electrically insulating property, having a tooth tip covering portion that covers the tip portions of the teeth and a tooth body covering portion that covers the parts of the teeth other than the tip portions; and a coil wound on the tooth body covering portion of the insulator, wherein the tooth tip covering portion comprises a circumferential end covering portion that covers the circumferential end of the stator core at the tip of the tooth and a tip surface covering portion that covers at least a part of the tip surface at the tip of the tooth, and the radial thickness of the stator core at the circumferential end covering portion is greater than the radial thickness of the tip surface covering portion.

2. A stator according to claim 1, wherein, when viewed in the axial direction, the tip surfaces of the teeth and the tip surface covering portion of the insulator are, at least a part of each, arc-shaped, and when viewed in the axial direction, the radius of curvature of the arc-shaped portion of the tip surface of the teeth is smaller than the radius of curvature of the arc-shaped portion of the tip surface covering portion of the insulator.

3. A stator according to claim 2, wherein, when the stator is viewed in the axial direction, the tip surfaces of the teeth and the tip surface covering portion of the insulator are, respectively, arc-shaped in the central part in the circumferential direction, and the circumferential ends are linear in that they are positioned towards the core back portion as they approach the circumferential end.

4. A stator according to claim 2, wherein the portion of the tip surface of the teeth that is located radially away from the core back portion is exposed.

5. A stator according to claim 4, wherein the portion of the tip surface of the teeth that is located radially away from the core back portion is the circumferential central portion of the tip surface of the teeth.

6. A stator according to claim 1, wherein at least one of the axial end faces at the tip of the teeth is exposed.

7. A stator according to claim 1, wherein the axial height of the tooth on the tip side of the tooth in the tooth body covering portion is the same as the axial height of the tooth on the base side of the tooth in the tooth body covering portion.

8. A stator according to claim 6, comprising: a rotation position detection unit for detecting the rotation position of a rotor; and a support unit for supporting the rotation position detection unit with respect to the stator core, wherein the support unit has a projection that protrudes axially from the stator core side toward the tip of the teeth and contacts the axial end face exposed at the tip of the teeth to position the rotation position detection unit axially with respect to the stator core.

9. A stator according to claim 8, wherein the support portion has a fixed projection that protrudes from the stator core side toward the tip of the teeth, and the tip of the teeth has an insertion hole in the exposed axial end face into which the fixed projection is inserted and fixed.

10. A motor comprising a stator according to any one of claims 1 to 9, and a rotor rotatable about the axis of the stator.

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