Stator unit and motor comprising the same

Abstract

To enhance the insulation performance of a motor stator while suppressing cost increase.SOLUTION: A stator unit 1 comprises: a stator core 2 having a plurality of teeth 2b; a plurality of coils 4 formed on an outer periphery of each of the teeth 2b with an insulator 3 in between; a plurality of insulation sheets 5 arranged between two coils 4 neighboring in a circumferential direction (slots 2d); and a flange portion 2c that prevents disconnection of the coils 4 at an inner diameter end of each of the teeth 2b. A concave portion 3c interposed in a radial direction between the flange portion 2c and the coils 4 is provided at an inner diameter end of the insulator 3, and a fitting piece 5a provided on an insulation sheet 5 is fitted into a radial gap δ formed between the flange portion 2c and the convex portion 3c.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a stator unit that constitutes the stationary side of a motor, and more particularly to a stator unit used in a drive motor such as an electric brake system for an automobile, and a motor including the stator unit. [Background technology]

[0002] For example, a stator (stator unit) used in an inner rotor type motor includes a cylindrical yoke, a stator core having a plurality of teeth extending radially inward from the yoke and spaced apart in the circumferential direction, a plurality of coils formed by winding coil wires around the outer periphery of each tooth, and an insulating member interposed between the stator core and the coils to electrically insulate them from each other. As the insulating member, a resin molded product called a bobbin or insulator, which has good attachment properties to the stator core, is often used (for example, Patent Document 1). In addition, in the stator unit described in Patent Document 1, a strip of insulating paper is placed between two coils (slots) adjacent to each other in the circumferential direction to ensure insulation between the coils. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-320136 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, conventional automobiles generally adopted a power supply system with a battery with a rated voltage of 12V, but in recent automobiles (new automobiles) where various systems are increasingly being electrified, power supply systems equipped with higher voltage, larger capacity batteries may be adopted. In this case, in order to stabilize the motor output, it is desirable to strengthen the insulation between the stator core and the coil, and between two adjacent coils. However, it is preferable to suppress the cost of strengthening the insulation as much as possible.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a stator unit having enhanced insulation between components without incurring a significant increase in cost. [Means for solving the problem]

[0006] The free radial end of the tooth (the inner diameter end in the stator unit of an inner rotor type motor, and the outer diameter end in the stator unit of an outer rotor type motor) is provided with a flange (a convex portion protruding outward in the circumferential direction) for the purpose of preventing the coil formed on the outer periphery of the tooth from coming off and improving motor performance. In this case, it is preferable to provide a convex portion interposed between the flange and the coil and improving insulation between the two on the free radial end of the insulator attached to the stator core. However, when the inventors verified, there were cases where insulation between the stator core and the coil could not be sufficiently ensured by merely interposing the convex portion of the insulator between the flange of the stator core and the coil. Therefore, the inventors came up with the idea of ​​strengthening the insulation between the stator core and the coil by using insulating paper arranged between two adjacent coils (teeth), and came up with the present invention.

[0007] That is, the present invention, which has been invented to achieve the above object, is a stator unit comprising: a cylindrical yoke, a stator core having a plurality of teeth extending radially from the yoke to one side and spaced apart in the circumferential direction; a plurality of coils formed by winding coil wire around each tooth via an insulator made of a resin molded product attached to the stator core; and a plurality of insulating papers arranged between two circumferentially adjacent coils, the radial free ends of the teeth being provided with flanges for preventing the coils from coming loose. The insulator is provided with a protrusion interposed radially between the flange and the coil, and the insulating paper has a fitting piece fitted into the radial gap between the flange and the protrusion.

[0008] The present invention can be applied to both stator units for so-called inner rotor motors and outer rotor motors. In other words, the "one-sided radial type" defined in claim 1 means the "inner radial side" in the case of the inner rotor type and the "outer radial side" in the case of the outer rotor type.

[0009] As described above, by fitting the fitting pieces provided on the insulating paper into the radial gap between the flanges of the teeth and the protrusions of the insulator, it becomes possible to block the conductive path between the flanges of the teeth and the coil with the fitting pieces (the fitting pieces increase the creepage distance between the flanges of the teeth, which are conductors, and the coil). This makes it possible to realize a stator unit with enhanced insulation between the stator core and the coil without incurring a significant increase in cost.

[0010] In the above configuration, the insulating paper may have a pair of the fitting pieces and an elastic support portion interposed between the fitting pieces and elastically supporting the fitting pieces so that the fitting pieces can move toward and away from each other in the circumferential direction. In this case, one and the other of the pair of fitting pieces are fitted into radial gaps provided on one and the other circumferential sides of the insulating paper, respectively, by utilizing the elastic restoring force of the elastic support portion. This allows the insulating paper to be attached easily and securely.

[0011] Either the stator core or the insulator forming the radial gap can be provided with an engagement surface that axially engages with the fitting piece fitted into the radial gap to position the insulating paper relative to the stator core, thereby preventing the fitting piece (the insulating paper having the fitting piece) fitted into the radial gap from coming off and preventing a decrease in insulation performance due to the insulating paper coming off.

[0012] The insulator can be formed by joining a first insulator-forming member arranged on one axial side and a second insulator-forming member arranged on the other axial side. In this case, it is preferable to fit a convex portion provided at one axial end of the second insulator-forming member into the inner periphery of a concave portion provided at the end on the other axial side of the first insulator-forming member.

[0013] A motor comprising the stator unit of the present invention described above and a rotor unit having an output shaft can be a high-quality motor with stable output because the stator unit of the present invention has the characteristics described above. Effect of the Invention

[0014] As described above, according to the present invention, it is possible to realize a stator unit having reinforced insulation between constituent members without incurring an increase in cost. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic perspective view of a stator unit according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view of the stator unit shown in FIG. [Diagram 3] FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Diagram 5]FIG. 1A is a cross-sectional view of the insulating paper inserted into the slot, and FIG. 1B is a cross-sectional view of the insulating paper when inserted into the slot. [Figure 6] FIG. 2 is an exploded perspective view of a stator unit. [Figure 7] FIG. 1A is a partially enlarged plan view of the stator unit before insulating paper is inserted, and FIG. 1B is a partially schematic perspective view of FIG. 1A as viewed from the direction of arrow B in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings (FIGS. 1 to 7).

[0017] FIG. 1 is a schematic perspective view of a stator unit 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the stator unit 1, but the insulating paper 5 depicted in FIG. 2 is omitted in FIG. 1. The stator unit 1 shown in FIG. 1 and FIG. 2 constitutes the stationary side of an inner rotor type three-phase motor having U-phase, V-phase, and W-phase, and includes a stator core 2, an insulator 3 as an insulating member, a plurality of coils 4, and insulating paper 5. That is, a rotor unit (not shown) including an output shaft of the motor is disposed on the inner circumference of the stator core 2. The "axial direction," "radial direction," and "circumferential direction" referred to in the following description are the direction parallel to the central axis O of the stator core 2, the radial direction of a circle centered on the central axis O, and the circumferential direction, respectively.

[0018] The stator core 2 has a cylindrical yoke 2a and a plurality of teeth 2b (here, 12 in total) that extend radially inward from the inner peripheral surface of the yoke 2a and are spaced apart in the circumferential direction, and a flange portion 2c that is arc-shaped in a plan view is formed at the radial free end (inner diameter end) of each tooth 2b. A slot 2d is defined between two adjacent teeth 2b in the circumferential direction, and insulating paper 5 is inserted (housed) in each slot 2d. The stator core 2 can be, for example, one in which a plurality of electromagnetic steel sheets are stacked in the axial direction, or one in which a magnetic powder compact is heated and sintered.

[0019] As described above, since the stator unit 1 of this embodiment is a stator unit for a three-phase motor, the coils 4 include U-phase coils, V-phase coils, and W-phase coils. Each coil 4 is formed by winding a coil wire 6 around the outer periphery of each tooth 2b via an insulator 3, and in this embodiment, which employs a stator core 2 having a total of 12 teeth 2b, four U-phase coils, four V-phase coils, and four W-phase coils are provided. Each coil 4 is formed by so-called concentrated winding.

[0020] One end of a bus bar 7 made of a metal material having high electrical conductivity such as copper or aluminum alloy is electrically connected to an end of the coil wire 6 constituting the U-phase coil, an end of the coil wire 6 constituting the V-phase coil, and an end of the coil wire 6 constituting the W-phase coil, and a current for driving the motor is supplied to each coil 4 via the bus bar 7. A pin-shaped terminal 7a extending in the axial direction is formed on the other end of each bus bar 7, and when the terminal 7a is inserted into a terminal insertion hole of a substrate (not shown) arranged axially outside the stator unit 1, a control unit of the motor provided on the substrate and the coil 4 are electrically connected.

[0021] Fig. 3 is a partial plan view of the insulator 3, and Fig. 4 is a cross-sectional view taken along line AA in Fig. 3. As shown in Fig. 4, the insulator 3 of this embodiment is formed by integrally joining a first insulator-forming member 31 disposed on one axial side and a second insulator-forming member 32 disposed on the other axial side at approximately the middle of the stator core 2 in the axial direction.

[0022] As shown in Fig. 3 and Fig. 4, the first insulator forming member 31 integrally includes a yoke covering portion 3a capable of covering one end face and an inner peripheral surface (a part of the axial region) of the yoke 2a of the stator core 2, and a plurality of (here, a total of 12) tooth covering portions 3b extending radially inward from the yoke covering portion 3a and arranged at intervals in the circumferential direction. The second insulator forming member 32 integrally includes a yoke covering portion (not shown) capable of covering the other end face and an inner peripheral surface (the remaining axial region) of the yoke 2a of the stator core 2, and a total of 12 tooth covering portions 3b extending radially inward from the yoke covering portion and arranged at intervals in the circumferential direction. Each tooth covering portion 3b is formed into a vertically long (horizontally long on the paper surface of Fig. 4) concave cross section, and the tooth covering portions 3b of the paired insulator forming members 31, 32 cooperate to cover the entire outer periphery of the tooth 2b.

[0023] The first insulator forming member 31 is attached to the stator core 2 by moving it from one axial side to the other axial side of the stator core 2, and the second insulator forming member 32 is attached to the stator core 2 by moving it from the other axial side to one side, and the two insulator forming members 31, 32 are joined together by fitting a convex portion 34 provided at one axial end of the second insulator forming member 32 into an inner periphery of a concave portion 33 provided at an end on the other axial side of the first insulator forming member 31. By employing the above-mentioned concave-convex fitting structure, the two insulator forming members 31, 32 can be joined together with high precision, thereby preventing the occurrence of insulation defects caused by poor joining between the two members as much as possible.

[0024] Both insulator-forming members 31, 32 are resin injection-molded products, and the first insulator-forming member 31 (the yoke covering portion 3a thereof) insulates and holds the multiple bus bars 7 in a non-contact state. The multiple bus bars 7 may be disposed as insert parts in a molding die for the insulator-forming member 31, or may be outsert parts attached to the insulator-forming member 31 after molding.

[0025] 2, the insulator 3 (insulator forming members 31, 32) is provided with a protruding portion 3c interposed between the flange portion 2c of the stator core 2 and the inner diameter end portion of the coil 4. A radial gap δ is formed between the flange portion 2c and the protruding portion 3c, and a fitting piece 5a of the insulating paper 5 inserted between (a slot 2d defined between) two coils 4 adjacent to each other in the circumferential direction is fitted into this radial gap δ.

[0026] In this way, by fitting the fitting piece 5a provided on the insulating paper 5 into the radial gap δ formed between the flange 2c of the tooth 2b and the protruding part 3c of the insulator 3, it becomes possible to cut off the radial conductive path formed between the flange 2c of the tooth 2b and the coil 4 with the fitting piece 5a of the insulating paper 5 (the creepage distance between the flange 2c of the tooth 2b, which is a conductor, and the coil 4 is increased by the fitting piece 5a). The insulating paper 5 of this embodiment, to which the fitting piece 5a is added, has a larger surface area (amount of paper used) than insulating paper without the fitting piece 5a, which increases the cost, but the increase is very small. Therefore, it is possible to realize a stator unit 1 with enhanced insulation between the stator core 2 and the coil 4 without incurring a significant increase in cost.

[0027] Fig. 5(a) shows a cross-sectional view of the insulating paper 5 in a state inserted into the slot 2d (a state in which the fitting pieces 5a are fitted into the radial gap δ), and Fig. 5(b) shows a cross-sectional view of the insulating paper 5 when inserted into the slot 2d. As shown in both figures, the insulating paper 5 is composed of a pair of fitting pieces 5a arranged at a distance in the circumferential direction, and a V-shaped elastic support portion 5b that is interposed between the fitting pieces 5a and elastically supports the fitting pieces 5a so that they can move toward and away from each other, and also insulates between two adjacent coils 4. As shown in Figs. 5(a) and 5(b), the circumferential dimension W of the insulating paper 5 when inserted into the slot 2d is larger than the circumferential dimension W' of the insulating paper 5 when the insertion operation into the slot 2d is performed. That is, the insulating paper 5 is attached by inserting the insulating paper 5, with both fitting pieces 5a closer to each other than in their natural state (with the elastic support portions 5b compressed and deformed in the circumferential direction) from one axial end to the other axial end of the slot 2d of the stator core 2 (see FIG. 6), and the circumferential compressive force applied to the elastic support portions 5b is released when a part or all of the axial length of the insulating paper 5 is inserted into the slot 2d. As a result, the fitting pieces 5a move apart in the circumferential direction under the elastic restoring force of the elastic support portions 5b, and fit into the radial gaps δ provided on both circumferential sides of the slot 2d.

[0028] In order to allow the insulating paper 5 to properly exert its insulating performance, it is necessary to properly manage the relative axial positions of the stator core 2 and the insulating paper 5 while preventing the insulating paper 5 inserted into the slot 2d (and the radial gap δ) from falling out. Therefore, an engagement surface 8 that can be engaged in the axial direction with the engagement piece 5a engaged in the radial gap δ is provided at a predetermined axial position on either the stator core 2 or the insulator 3 that forms the radial gap δ into which the engagement piece 5a of the insulating paper 5 is engaged. A specific configuration adopted in this embodiment will be described with reference to Figs. 7(a) and 7(b). Fig. 7(a) is a partially enlarged plan view of the stator unit 1 before the insulating paper 5 is inserted, and Fig. 7(b) is a partially schematic perspective view of Fig. 7(a) as viewed from the direction of the arrow B in Fig. 7(a). In order to facilitate understanding, the coil 4 shown in Fig. 7(a) is omitted in Fig. 7(b).

[0029] 7(a) and 7(b), in this embodiment, an engagement surface 8 is provided at the other axial end of the insulator 3 (a second insulator forming member 32 constituting the insulator), and when the entire insulating paper 5 is inserted (housed) in the slot 2d, the end of the fitting piece 5a of the insulating paper 5 on the forward side in the insertion direction engages (abuts) with the engagement surface 8. This makes it possible to properly manage the relative axial positions of the stator core 2 and the insulating paper 5 while preventing the insulating paper 5 inserted into the slot 2d from falling out.

[0030] Although the stator unit 1 according to one embodiment of the present invention has been described above, the embodiment of the present invention is not limited to this.

[0031] For example, the present invention has been described above as being applied to the stator unit 1 constituting the stationary side of an inner rotor type motor (three-phase motor), but the present invention can also be applied to a stator unit constituting the stationary side of an outer rotor type motor. Although not shown, a stator core for an outer rotor type motor is used that includes a cylindrical yoke and a plurality of teeth extending radially outward from the outer circumferential surface of the yoke and spaced apart in the circumferential direction. Therefore, a flange for preventing the coil from coming off is provided at the outer diameter end of the teeth, and a protrusion of the insulator that forms a radial gap δ between the flange of the teeth and the flange of the teeth, into which the fitting piece 5a of the insulating paper 5 is fitted, is provided at the outer diameter end of the insulator.

[0032] The present invention is not limited to the above-described embodiment, and can be embodied in various other forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0033] 1 Stator unit 2 Stator core 2a York 2b Teeth 2c Tsubabe 3. Insulator 3c Convex part 4 Coils 5. Insulating paper 5a Mating piece 5b Elastic support part 6 Coil Wire 7 Busbar 8 Engagement surface 31 First insulator forming member 32 Second insulator forming member δ Radial clearance

Claims

1. a stator core having a cylindrical yoke and a plurality of teeth extending radially from the yoke to one side and spaced apart in a circumferential direction; a plurality of coils formed by winding coil wires around each of the teeth via an insulator made of a resin molded product attached to the stator core; a plurality of insulating papers disposed between two coils adjacent to each other in the circumferential direction; In a stator unit, a flange portion for preventing the coil from coming off is provided at a radial free end of the tooth, A stator unit characterized in that the insulator has a convex portion interposed radially between the flange portion and the coil, and the insulating paper has a fitting piece that fits into the radial gap between the flange portion and the convex portion.

2. the insulating paper has a pair of the fitting pieces and an elastic support portion interposed between the fitting pieces and elastically supporting the fitting pieces so that the fitting pieces can move toward and away from each other in a circumferential direction, 2. A stator unit as described in claim 1, wherein one and the other of the pair of fitting pieces are fitted into the radial gaps provided on one and the other circumferential sides of the insulating paper, respectively, by utilizing the elastic restoring force of the elastic support portion.

3. A stator unit as described in claim 1, wherein one of the stator core and the insulator which form the radial gap is provided with an engagement surface which axially engages with the mating piece fitted into the radial gap to position the insulating paper axially relative to the stator core.

4. the insulator is formed by joining a first insulator-forming member disposed on one axial side and a second insulator-forming member disposed on the other axial side, 2. The stator unit according to claim 1, wherein a convex portion provided at one axial end of the second insulator forming member is fitted into an inner periphery of a concave portion provided at the other axial end of the first insulator forming member.

5. A motor comprising the stator unit according to any one of claims 1 to 4, and a rotor unit having an output shaft.

Images