Stator

Abstract

A stator (10) comprises: a stator core (24) having a plurality of radially extending teeth parts (20); a resin insulator (16) attached to the stator core; and a winding part (18) wound around the plurality of teeth parts via the insulator. The insulator has mounting parts (30, 32) mounted on mounting surfaces (20A, 22A) of the stator core. Grooves (34, 36) open to the mounting surface side are formed in the mounting parts. Gas layers (38, 40) are formed by the grooves between the stator core and the winding part.

Description

Stator CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Japanese Patent Application No. 2024-015189, filed February 2, 2024, the entire contents of which are incorporated herein by reference.

[0002] The technology of the present disclosure relates to a stator.

[0003] In the technical field of stators, a stator is known that includes a stator core having a plurality of radially extending teeth, an insulating film attached to the stator core, and a winding wound around the plurality of teeth via the insulating film (see, for example, JP 2018-198515 A). This stator is said to be capable of improving assembly ease and insulation reliability.

[0004] As a result of detailed investigation by the inventors, it was found that in the above-mentioned stator, the use of an insulating film shortens the distance between the teeth and the windings, which means that it is not possible to reduce stray capacitance, which is a capacitance component generated by the potential difference between the stator core and the windings.

[0005] The technique of the present disclosure provides a stator that can reduce stray capacitance.

[0006] A stator according to one aspect of the disclosed technology comprises a stator core having a plurality of radially extending tooth portions, a resin insulator attached to the stator core, and a winding winding portion wound around the plurality of tooth portions via the insulator, wherein the insulator has a mounting portion attached to a mounting surface of the stator core, and a groove is formed in the mounting portion that opens toward the mounting surface, and a gas layer is formed between the stator core and the winding winding portion by the groove.

[0007] According to the technique of the present disclosure, a stator capable of reducing stray capacitance is provided.

[0008] 1 is a plan view of a stator according to an embodiment of the technology of the present disclosure. FIG. 2 is a plan view of a stator component. FIG. 3 is an enlarged view of a portion A of FIG. 2. FIG. 4 is a further enlarged view of a portion A of FIG. 2. FIG. 5 is a perspective view of a stator component. FIG. 6 is a perspective view of a first insulator. FIG. 7 is a two-sided view of the first insulator. FIG. 8 is an explanatory diagram for explaining stray capacitance. FIG. 9 is an enlarged view of a main part of a stator component according to a first modified example. FIG. 10 is a longitudinal sectional view of a first insulator according to a first modified example. FIG. 11 is an enlarged view of a main part of a stator component according to a second modified example. FIG. 12 is an enlarged view of a main part of a stator component according to a third modified example. FIG. 13 is a perspective view of a stator component according to a fourth modified example. FIG. 14 is a perspective view of a stator component according to a fifth modified example. FIG. 15 is a perspective view of a first insulator according to a sixth modified example. FIG. 16 is a plan view of a first insulator according to the sixth modified example. FIG. 17 is a perspective view of a first insulator according to a seventh modified example.

[0009] Hereinafter, an embodiment of the technology of the present disclosure will be described with reference to the drawings.

[0010] As shown in FIG. 1 , a stator 10 according to this embodiment includes a plurality of stator components 12. The stator 10 is configured by combining a plurality of stator components 12 in an annular shape. FIG. 1 shows the configuration of half of the stator 10. The stator 10 is applied to a brushless motor. Brushless motors may be used for any purpose. Examples of brushless motors include fan motors, pump drive motors, and compressor motors.

[0011] In each figure, the X direction indicates the tangential direction of the stator 10, the Y direction indicates the radial direction of the stator 10, and the Z direction indicates the axial direction of the stator 10. In the following description, the circumferential direction of the stator 10 refers to the direction around the central axis of the stator 10. The tangential direction, radial direction, axial direction, and circumferential direction of the stator core 24, which will be described later, are the same directions as the tangential direction, radial direction, axial direction, and circumferential direction of the stator 10, respectively.

[0012] As shown in Fig. 2, each stator component 12 includes a core member 14, an insulator 16, and a winding winding portion 18. The core member 14 has teeth portions 20 and a core back portion 22. The core back portion 22 extends in the circumferential direction of the stator core 24 (see Fig. 1), and the teeth portions 20 extend inward in the Y direction from the center of the core back portion 22. The tip portions of the teeth portions 20 are free ends, and the base ends of the teeth portions 20 are connected to the core back portion 22.

[0013] A stator core 24 (see FIG. 1) is formed by combining a plurality of core members 14 in an annular shape. When the stator core 24 is formed, the plurality of core back portions 22 form an annular portion 26 (see FIG. 1) that is the outer periphery of the stator core 24, and the plurality of teeth portions 20 extend radially from the center of the stator core 24. Slots 28 are formed between the plurality of teeth portions 20.

[0014] Note that the configuration of each stator component 12, including its details, is not strictly symmetrical in the X direction when viewed from the Z direction. However, for the sake of convenience, the following description will assume that the main configuration of each stator component 12 is symmetrical in the X direction when viewed from the Z direction, and will explain the configuration of one side of each stator component 12.

[0015] As shown in Fig. 3, the tooth portion 20 has a side surface 20A, and the core back portion 22 has an inner surface 22A. The side surface 20A extends in the Y direction and the Z direction and faces the X direction. The inner surface 22A extends in the X direction and the Z direction and faces inward in the Y direction. The side surface 20A and the inner surface 22A are in contact with the slot 28.

[0016] The insulator 16 is attached to the core member 14. The insulator 16 is made of resin. Examples of resins that can be used to form the insulator 16 include polyimide, polyamide, polyphenylene sulfide (PPS), and polybutylene terephthalate (PBT). Any resin can be used to form the insulator 16. The insulator 16 has a side wall portion 30 and an inner wall portion 32. The side wall portion 30 is attached to the side surface 20A and covers the side surface 20A. The inner wall portion 32 is attached to the inner surface 22A and covers the inner surface 22A. The side wall portion 30 and the inner wall portion 32 are disposed in the slot 28.

[0017] The side surface 20A and the inner surface 22A are an example of a "mounting surface" according to the present disclosure. The side wall portion 30 and the inner wall portion 32 are an example of a "mounting portion" according to the present disclosure. The side wall portion 30 is an example of a "first mounting portion" according to the present disclosure, and the inner wall portion 32 is an example of a "second mounting portion" according to the present disclosure.

[0018] The winding portion 18 is wound around the tooth portion 20 via the insulator 16. The winding portion 18 is formed by winding a wire around the tooth portion 20 in the Y direction. A single winding forming the winding portion 18 may be wound around only one tooth portion 20 to form only one winding portion 18, or may be wound around multiple teeth portions 20 to form several winding portions 18.

[0019] The side wall portion 30 has an opposing surface 30A facing the side surface 20A, and the inner wall portion 32 has an opposing surface 32A facing the inner surface 22A. A first groove 34 is formed in the opposing surface 30A of the side wall portion 30, and a second groove 36 is formed in the opposing surface 32A of the inner wall portion 32. The first groove 34 opens to the side surface 20A, and the second groove 36 opens to the inner surface 22A. As an example, two first grooves 34 are formed in the opposing surface 30A of the side wall portion 30. The two first grooves 34 are aligned in the Y direction. Also, as an example, one second groove 36 is formed in the opposing surface 32A of the inner wall portion 32.

[0020] A first gas layer 38 is formed by the first groove 34 between the tooth portion 20 and the winding portion 18 in the X direction, and a second gas layer 40 is formed by the second groove 36 between the core back portion 22 and the winding portion 18 in the Y direction. In other words, the first gas layer 38 is formed inside the first groove 34, and the second gas layer 40 is formed inside the second groove 36. The first groove 34 and the second groove 36 are formed to penetrate in the Z direction.

[0021] The first groove 34 and the second groove 36 are examples of "grooves" according to the present disclosure. The first gas layer 38 and the second gas layer 40 are examples of "gas layers" according to the present disclosure.

[0022] 4, the side wall portion 30 has an abutment portion 42. The abutment portion 42 is formed adjacent to the first groove 34 and abuts against the side surface 20A. Similarly, the inner wall portion 32 has an abutment portion 44. The abutment portion 44 is formed adjacent to the second groove 36 and abuts against the inner surface 22A.

[0023] More specifically, the abutment portion 42 formed on the side wall portion 30 has a first abutment portion 46 formed at one end of the side wall portion 30 in the Y direction, which is the extension direction of the tooth portion 20, a second abutment portion 48 formed at the other end of the side wall portion 30 in the Y direction, and a third abutment portion 50 formed in the center of the side wall portion 30 in the Y direction.

[0024] The winding portions 52 of the first turn of the winding winding portion 18 located on the side wall 30 side are aligned in the Y direction, which is the extension direction of the tooth portion 20. The winding portions 52 have extended winding portions 52A located on an extension line L, which is an extension of the boundary line between the first groove 34 and the abutment portion 42 in the normal direction of the side surface 20A of the tooth portion 20. The winding portions 52 are aligned so that the apex 52A1 of the extended winding portion 52A on the side wall 30 side is located on the extension line L. The apex 52A1 of the extended winding portion 52A is a contact point that comes into contact with the side wall 30.

[0025] More specifically, the abutment portion 44 formed on the inner wall portion 32 has a first abutment portion 54 formed at one end of the inner wall portion 32 in the X direction and a second abutment portion 56 formed at the other end of the inner wall portion 32 in the X direction.

[0026] 5 , the insulator 16 is composed of a first insulator 58 and a second insulator 60 that are divided in the Z direction. A dividing portion 62 that divides the first insulator 58 and the second insulator 60 in the Z direction is located, for example, in the center of the tooth portion 20 in the Z direction. The first insulator 58 and the second insulator 60 are connected at the dividing portion 62.

[0027] The winding portion 18 has an axial wiring portion 64 that is wired in the Z direction along the side wall portion 30 of the tooth portion 20 (see Figure 6), a coil end portion 66 that is wired on one side of the tooth portion 20 in the Z direction, and a coil end portion 68 that is wired on the other side of the tooth portion 20 in the Z direction.

[0028] As shown in Fig. 6 , the first insulator 58 has a coil end insulating portion 70. The coil end insulating portion 70 connects one end of the pair of side wall portions 30 in the Z direction. The coil end insulating portion 70 is disposed between the tooth portion 20 and the coil end portion 66 (see Fig. 5 ) and insulates the tooth portion 20 from the coil end portion 66.

[0029] Positioning portions 72 are formed at the connection portions (corners) between the coil end insulating portions 70 and the side wall portion 30. The positioning portions 72 are formed by uneven portions repeatedly arranged in the Y direction. The positioning portions 72 position the multiple winding portions 52 (see FIG. 4 ) of the first turn of the winding winding portion 18, so that, as described above, the multiple winding portions 52 are aligned so that the apex 52A1 of the extended winding portion 52A on the side wall portion 30 side is positioned on the extension line L.

[0030] 7, the first groove 34, the second groove 36, the contact portion 42, and the contact portion 44 extend in the Z direction and reach the dividing portion 62. The second insulator 60 has the same configuration as the first insulator 58, and therefore a description thereof will be omitted.

[0031] Next, the operation and effects of this embodiment will be described.

[0032] Here, stray capacitance will be explained with reference to Fig. 8. Stray capacitance refers to the capacitance component generated by the potential difference between the winding winding portion 18 and the stator core 24. The stray capacitance is calculated using the following theoretical formula. In the following theoretical formula, the relative permittivity refers to the relative permittivity of the insulator 16, the surface area refers to the surface area of ​​the stator core 24, and the distance refers to the distance between the stator core 24 and the winding winding portion 18. Stray capacitance ∝ relative permittivity × surface area / distance

[0033] There is a risk that stray capacitance will induce noise due to electrostatic induction in the inverter that supplies current to the winding 18. One possible solution to this problem is to install a noise cut filter in the inverter, but installing a noise cut filter in the inverter increases costs.

[0034] In this regard, in the present embodiment, a first gas layer 38 is formed by the first groove 34 between the tooth portion 20 and the winding portion 18 in the X direction. Therefore, the first gas layer 38 can lower the relative dielectric constant, thereby reducing the stray capacitance between the tooth portion 20 and the winding portion 18. Furthermore, a second gas layer 40 is formed by the second groove 36 between the core back portion 22 and the winding portion 18 in the Y direction. Therefore, the second gas layer 40 can lower the relative dielectric constant, thereby reducing the stray capacitance between the core back portion 22 and the winding portion 18.

[0035] Furthermore, by forming the first gas layer 38 and the second gas layer 40 between the winding portion 18 and the stator core 24, the stray capacitance between the winding portion 18 and the stator core 24 can be reduced, which eliminates the need to install a noise cut filter in the inverter, thereby preventing costs from increasing.

[0036] Furthermore, since a first gas layer 38 is formed between the tooth portion 20 and the winding winding portion 18, and a second gas layer 40 is formed between the core back portion 22 and the winding winding portion 18, the stray capacitance between the stator core 24 and the winding winding portion 18 can be reduced both between the tooth portion 20 and the winding winding portion 18 and between the core back portion 22 and the winding winding portion 18, compared to when only one of the first gas layer 38 and the second gas layer 40 is formed.

[0037] Furthermore, by forming the first gas layer 38 between the tooth portion 20 and the side wall portion 30 by the first groove 34, the thickness of the side wall portion 30 can be made thinner than when the tooth portion 20 and the winding portion 18 are insulated only by the side wall portion 30. Similarly, by forming the second gas layer 40 between the core back portion 22 and the inner wall portion 32 by the second groove 36, the thickness of the inner wall portion 32 can be made thinner than when the core back portion 22 and the winding portion 18 are insulated only by the inner wall portion 32. This allows the cross-sectional area of ​​the slot 28 to be increased, which in turn allows the number of turns of the winding portion 18 to be increased, thereby preventing the stator 10 from becoming larger. In other words, it is possible to prevent the stator 10 from becoming larger in size in order to increase the cross-sectional area of ​​the slot 28.

[0038] Furthermore, the side wall portion 30 has a first abutment portion 46 formed at one end of the side wall portion 30 and a second abutment portion 48 formed at the other end of the side wall portion 30, and the first abutment portion 46 and the second abutment portion 48 abut against the side surface 20A of the tooth portion 20. As a result, the side wall portion 30 is supported by the side surface 20A of the tooth portion 20 at one end and the other end, so that rattle of the insulator 16 relative to the stator core 24 can be suppressed.

[0039] Furthermore, the side wall portion 30 has a third abutment portion 50 formed in the center of the side wall portion 30, and the third abutment portion 50 abuts against the side surface 20A of the tooth portion 20. As a result, the side wall portion 30 is supported at the center by the side surface 20A of the tooth portion 20, so that even when the first groove 34 is formed in the side wall portion 30, the side wall portion 30 can be prevented from bending toward the side surface 20A due to the tightening force of the winding winding portion 18.

[0040] Furthermore, the first grooves 34 are open not to the winding portion 18 side but to the side of the side wall 30 facing the side of the sidewall ...

[0041] The inner wall portion 32 has a first abutment portion 54 formed at one end of the inner wall portion 32 and a second abutment portion 56 formed at the other end of the inner wall portion 32, and the first abutment portion 54 and the second abutment portion 56 abut against the inner surface 22A of the core back portion 22. As a result, the inner wall portion 32 is supported at one end and the other end by the inner surface 22A of the core back portion 22, so that rattle of the insulator 16 relative to the stator core 24 can be suppressed.

[0042] In addition, the multiple winding portions 52 of the first turn located on the side wall portion 30 side of the winding winding portion 18 have extended winding portions 52A located on an extension line L extending the boundary line between the first groove 34 and the abutment portion 42 in the normal direction of the side surface 20A of the tooth portion 20, and the top 52A1 on the side wall portion 30 side of the extended winding portion 52A is located on the extension line L. Therefore, for the top 52A1 of the extended winding portion 52A, which is close to the tooth portion 20, the boundary between the first groove 34 and the abutment portion 42 is assigned as an insulating portion. Therefore, the stray capacitance between the tooth portion 20 and the extended winding portion 52A can be reduced compared to, for example, a configuration in which only the abutment portion 42 is assigned as an insulating portion for the top 52A1 of the extended winding portion 52A, i.e., a configuration in which the entire area between the tooth portion 20 and the top 52A1 of the extended winding portion 52A is a resin portion.

[0043] Next, a modification of this embodiment will be described.

[0044] In the above embodiment, a first gas layer 38 is formed between the tooth portion 20 and the winding portion 18, and a second gas layer 40 is formed between the core back portion 22 and the winding portion 18, but either the first gas layer 38 or the second gas layer 40 may be omitted.

[0045] In the above embodiment, the insulator 16 is composed of the first insulator 58 and the second insulator 60 that are separated in the Z direction, but the insulator 16 may be configured such that the first insulator 58 and the second insulator 60 are integrated, i.e., formed in a ring shape around the tooth portion 20. In this case, the tooth portion 20 may be formed in a straight shape in the Y direction (i.e., a cross section with a constant shape in the Y direction) so that the tooth portion 20 can be inserted inside the insulator 16.

[0046] In addition, in the above embodiment, a third abutment portion 50 is formed in the center of the side wall portion 30, and a first groove 34 is formed on both sides of the third abutment portion 50 on the opposing surface 30A of the side wall portion 30, but as shown in Figures 9 and 10, the third abutment portion 50 may be omitted from the center of the side wall portion 30, and only one first groove 34 may be formed on the opposing surface 30A of the side wall portion 30.

[0047] In the above embodiment, the width of the third contact portion 50 along the Y direction is set to be the same as the width (diameter) of one winding portion 52 (see FIG. 4 ), but as shown in FIG. 11 , the width of the third contact portion 50 along the Y direction may be set to be the same as the width of multiple winding portions 52. In the example shown in FIG. 11 , the width of the third contact portion 50 along the Y direction is set to be the same as the width of two winding portions 52.

[0048] Furthermore, in the above embodiment, the multiple winding portions 52 are aligned so that the top 52A1 on the side wall portion 30 side of the extended winding portion 52A is positioned on the extension line L, but as shown in Figure 12, the multiple winding portions 52 may all be aligned so that their tops are offset from the extension line L.

[0049] In the above embodiment, the insulator 16 is composed of a first insulator 58 and a second insulator 60 that are divided in the Z direction, and the first insulator 58 and the second insulator 60 are connected at the dividing portion 62. However, as shown in Fig. 13, the first insulator 58 and the second insulator 60 may be separated in the Z direction. Also, as shown in Fig. 14, the first insulator 58 and the second insulator 60 may be configured to be attached to both ends of the core member 14 in the Z direction.

[0050] Furthermore, in the above embodiment, the insulator 16 has a coil end insulating portion 70 disposed between the tooth portion 20 and the coil end portion 66. However, as shown in Figures 15 and 16, the coil end insulating portion 70 may have openings 74 that open in the Z direction. The openings 74 may penetrate in the Z direction, or may be formed in a concave shape that opens only on one side or the other side in the Z direction. There may be any number of openings 74. With this configuration, a gas layer is formed between the tooth portion 20 and the coil end portion 66 by the openings 74, thereby reducing the stray capacitance between the tooth portion 20 and the coil end portion 66.

[0051] In addition, in the above embodiment, a positioning portion 72 is formed at the connection portion between the coil end insulating portion 70 and the side wall portion 30, but as shown in Figure 17, the positioning portion 72 may be omitted from the connection portion (corner portion) between the coil end insulating portion 70 and the side wall portion 30.

[0052] Among the above multiple modified examples, modified examples that can be combined may be combined as appropriate.

[0053] The above describes one embodiment of the present disclosure, but the present disclosure is not limited to the above, and it goes without saying that various modifications can be made to the present disclosure without departing from the spirit of the present disclosure.

[0054] The following are supplementary notes regarding the present disclosure: (Supplementary Note 1) A stator (10) comprising: a stator core (24) having a plurality of radially extending teeth (20), a resin insulator (16) attached to the stator core, and a winding (18) wound around the plurality of teeth via the insulator, wherein the insulator has a mounting portion (30, 32) attached to a mounting surface (20A, 22A) of the stator core, and a groove (34, 36) opening toward the mounting surface is formed in the mounting portion, and a gas layer (38, 40) is formed between the stator core and the winding portion by the groove. (Supplementary Note 2) The stator core according to Supplementary Note 1, wherein the stator core has a core back portion (22) forming an outer periphery of the stator core, the teeth portions extend from the core back portion toward the radial inside of the stator core, the mounting surfaces have side surfaces (20A) of the teeth portions and an inner surface (22A) of the core back portion, the mounting portions have first mounting portions (30) mounted to the side surfaces of the teeth portions and second mounting portions (32) mounted to the inner surface of the core back portion, the grooves have first grooves (34) formed in the first mounting portions and opening to the side surfaces of the teeth portions, and second grooves (36) formed in the second mounting portions and opening to the inner surface of the core back portion, and the gas layers have a first gas layer (38) formed between the teeth portions and the winding winding portions, and a second gas layer (40) formed between the core back portion and the winding winding portions. (Supplementary Note 3) The first mounting portion has an abutment portion (42) formed adjacent to the first groove and abutting against a side surface of the tooth portion, and the abutment portion has a first abutment portion (46) formed at one end of the first mounting portion in the extension direction of the tooth portion and a second abutment portion (48) formed at the other end of the first mounting portion in the extension direction of the tooth portion. The stator according to Supplementary Note 2. (Supplementary Note 4) The stator according to Supplementary Note 3, wherein the abutment portion has a third abutment portion (50) formed in a central portion of the first mounting portion in the extension direction of the tooth portion.(Supplementary Note 5) The stator according to Supplementary Note 3 or Supplementary Note 4, wherein a plurality of winding portions (52) of a first turn of the winding portion located on the first mounting portion side are aligned in an extension direction of the tooth portion, the plurality of winding portions have an extended winding portion (52A) located on an extension line (L) obtained by extending a boundary line between the first groove and the abutment portion in a normal direction to a side surface of the tooth portion, and an apex (52A1) of the extended winding portion on the first mounting portion side is located on the extension line. (Supplementary Note 6) The stator according to any one of Supplementary Notes 1 to 5, wherein the winding portion has a coil end portion (66) wired on one axial side of the stator core relative to the tooth portion, the insulator has a coil end insulating portion (70) arranged between the tooth portion and the coil end portion, and the coil end insulating portion has an opening (74) opening in the axial direction of the stator core.

Claims

1. A stator (10) comprising: a stator core (24) having a plurality of radially extending teeth (20); a resin insulator (16) attached to the stator core; and a winding (18) wound around the plurality of teeth via the insulator, wherein the insulator has a mounting portion (30, 32) attached to a mounting surface (20A, 22A) of the stator core, and a groove (34, 36) opening toward the mounting surface is formed in the mounting portion, and a gas layer (38, 40) is formed between the stator core and the winding by the groove.

2. The stator according to claim 1, wherein the stator core has a core back portion (22) forming the outer periphery of the stator core, the teeth extend from the core back portion toward the inside in the radial direction of the stator core, the mounting surface has a side surface (20A) of the teeth and an inner surface (22A) of the core back portion, the mounting portion has a first mounting portion (30) mounted to the side surface of the teeth and a second mounting portion (32) mounted to the inner surface of the core back portion, the grooves include a first groove (34) formed in the first mounting portion and opening to the side surface of the teeth, and a second groove (36) formed in the second mounting portion and opening to the inner surface of the core back portion, and the gas layer includes a first gas layer (38) formed between the teeth and the winding winding portion, and a second gas layer (40) formed between the core back portion and the winding winding portion.

3. The stator according to claim 2, wherein the first mounting portion has an abutment portion (42) formed adjacent to the first groove and abutting against a side surface of the tooth portion, the abutment portion having a first abutment portion (46) formed at one end of the first mounting portion in the extension direction of the tooth portion and a second abutment portion (48) formed at the other end of the first mounting portion in the extension direction of the tooth portion.

4. A stator according to claim 3, wherein the abutment portion has a third abutment portion (50) formed in a central portion of the first mounting portion in the extension direction of the teeth portion.

5. A stator as set forth in claim 3 or claim 4, wherein the plurality of winding portions (52) of the first turn of the winding winding portion located on the first mounting portion side are aligned in the extension direction of the tooth portion, the plurality of winding portions have an extended winding portion (52A) located on an extension line (L) extending the boundary line between the first groove and the abutment portion in the normal direction to the side surface of the tooth portion, and the apex (52A1) of the extended winding portion on the first mounting portion side is located on the extension line.

6. A stator as set forth in any one of claims 1 to 5, wherein the winding portion has a coil end portion (66) that is wired on one axial side of the stator core relative to the tooth portion, the insulator has a coil end insulating portion (70) that is arranged between the tooth portion and the coil end portion, and the coil end insulating portion has an opening (74) that opens in the axial direction of the stator core.

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