Rotating electrical machine

Abstract

In a rotating electric machine having a rotor and a stator, one of the rotor and the stator has: a slot portion formed in a circumferential surface facing the other of the rotor and the stator and extending in a direction intersecting the circumferential direction; and a resin-made cover portion covering the slot portion. The slot portion includes an anti-extraction portion formed so as to have a slot width at a second position, which is farther from the opening in the radial direction than a first position, that is greater than a slot width at the first position. The anti-extraction portion engages a resin material filled in the slot portion to prevent the cover portion from falling off.

Description

TECHNICAL FIELD

[0001] The present application relates to a rotary electric machine. BACKGROUND

[0002] In the past, as one of mechanical losses of a rotary electric machine, there has been known a wind loss generated by frictional resistance of a rotor and air in the vicinity of the rotor. If the surface shape of the rotor or the stator has a concave-convex shape, the wind loss becomes larger. For example, a tooth slot of a stator that houses a coil, a slot formed on the surface of the stator or the surface of the rotor in order to reduce torque ripple, and the like generate eddy currents when the rotor rotates, thereby becoming a main cause of an increase in the wind loss. For example, in Patent Literature 1, in order to reduce the wind loss of the rotary electric machine, a structure in which a resin covering layer that fills in the concave-convex shape is formed on the inner peripheral side of the stator and the inner peripheral surface of the stator is flattened is also proposed.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2016-185032 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] When the resin covering layer is formed on the surface of the stator to suppress the wind loss as in Patent Literature 1, the resin covering layer is easily peeled from the surface of the stator due to external forces such as vibration, centrifugal force, and the like.

[0008] The present application has been achieved in view of the above-described circumstances, and an object thereof is to provide a rotary electric machine capable of suppressing peeling of a resin covering layer for reducing a wind loss.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] One embodiment of the present application is a rotary electric machine including a rotor and a stator. One of the rotor and the stator includes a groove portion formed in a circumferential surface facing the other of the rotor and the stator and extending in a direction intersecting a circumferential direction, and a resin covering portion covering the groove portion. The groove portion includes an anti-extraction portion formed to have a groove width at a second position, which is farther apart from an opening in a radial direction than a groove width at a first position. The anti-extraction portion engages a resin material filled in the groove portion to prevent the covering portion from being peeled off.

[0011] The groove portion can be formed at a tip end of a tooth portion of the stator, and the covering portion can be formed at the entire circumference of the inner peripheral side of the stator.

[0012] Further, the resin material of the covering portion can further cover inside a tooth slot of the stator to insulate a coil arranged in the tooth slot from the stator.

[0013] In addition, the tooth groove can have a flow path that causes the refrigerant to flow to the outer diameter side of the coil.

[0014] The groove portion can be formed in the outer periphery of the rotor, and the cover portion can cover at least the groove portion of the outer peripheral surface of the rotor.

[0015] Effects of Invention

[0016] According to one embodiment of the present application, a rotating electric machine capable of suppressing peeling of a resin cover layer for reducing windage loss can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a drawing showing a structure example of the rotating electric machine of the present embodiment.

[0018] Figure 2 is Figure 1 is a partial enlarged view of

[0019] Figure 3 is Figure 2 is an enlarged view of the portion enclosed by the dotted line of DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present application will be described with reference to the drawings.

[0021] In the embodiments, structures and elements other than the main parts of the present application are simplified or omitted from the description for easy understanding. In the drawings, the same elements are marked by the same reference numerals. Note that the shapes, sizes, and the like of the elements shown in the drawings are schematic and not intended to limit the actual shapes, sizes, and the like.

[0022] In the following description, a direction parallel to the extension direction of the rotational axis Ax is referred to as the axial direction, a circumferential direction centered on the rotational axis Ax is simply referred to as the circumferential direction, and a radial direction centered on the rotational axis Ax is simply referred to as the radial direction. In the following description, "extending in the axial direction" includes not only extending strictly in the axial direction but also extending in a direction inclined with respect to the axial direction within a range of less than 45°. In the present specification, "extending in the radial direction" includes not only extending strictly in the radial direction, i.e., in a direction perpendicular to the axial direction, but also extending in a direction inclined with respect to the radial direction within a range of less than 45°. In addition, "parallel" includes not only a case where it is strictly parallel but also a case where the angle formed between them is inclined within a range of less than 45°.

[0023] Figure 1 is a drawing showing a structure example of the rotating electric machine of the present embodiment. Figure 2 is Figure 1 is a partial enlarged view of Figure 1 , Figure 2A cross section indicates a direction orthogonal to the rotational axis Ax in the rotary electric machine.

[0024] Figure 1 The rotary electric machine 1 shown is an inner rotor type machine applied to a vehicle motor or the like as an example. The rotary electric machine 1 has a rotor 2 and a stator 3 of a cylindrical shape arranged at an outer periphery of the rotor 2. In the rotary electric machine 1, the rotor 2 is arranged in the stator 3. Figure 1 , Figure 2 In the rotary electric machine 1, an extension direction of the rotational axis Ax is a paper vertical direction.

[0025] The rotor 2 is, for example, a rotor of a magnet embedded type or a surface magnet type. The rotor 2 has, for example, a rotor core 4 of a cylindrical shape in which a plurality of electromagnetic steel sheets are stacked in an axial direction. On the rotor core 4, a plurality of permanent magnets (not shown) are arranged so as to constitute main magnetic poles at equal intervals in a circumferential direction. In addition, a shaft 5 is embedded in the rotor core 4 so as to pass through the rotor core 4 in the axial direction along the rotational axis Ax at a center of the rotor core 4. The shaft 5 is supported by a bearing (not shown).

[0026] At an outer periphery of the rotor core 4, grooves 4a extending in the axial direction are respectively formed in order to reduce torque pulsation. The grooves 4a are formed in parallel at equal intervals in the circumferential direction of the rotor 2. Note that the grooves 4a can be formed in a skew shape inclined with respect to the axial direction.

[0027] In addition, a rotor cover layer 6 of a resin is formed at the outer periphery of the rotor core 4. The rotor cover layer 6 covers an outer peripheral surface of the rotor core 4 and the grooves 4a, and functions to fill gaps of the grooves 4a so as to form a uniform circular shape when the outer peripheral surface of the rotor 2 is viewed in the axial direction. The rotor cover layer 6 is formed of, for example, a thermosetting resin, and is a non-magnetic body that allows magnetic flux to pass therethrough.

[0028] The stator 3 accommodates the rotor 2 in a space portion centered on the rotational axis Ax. That is, the stator 3 is arranged in a concentric shape with the rotor 2 at the outer periphery of the rotor 2 with a slight air gap therebetween.

[0029] The stator 3 has a stator core 7, a coil 8, and a stator cover layer 9 of a resin. The stator core 7 is formed by stacking a plurality of electromagnetic steel sheets punched into a shape shown in the drawing in the axial direction. The stator core 7 has a yoke portion 7a formed entirely in a circumferential direction at a radially outer side and a plurality of tooth portions 7b extending from an inner peripheral side of the yoke portion 7a to a radially inner side. Figure 1

[0030] ​Multiple teeth 7b are arranged at equal intervals in the circumferential direction. Furthermore, tooth slots are formed between adjacent teeth 7b. In each tooth slot, a coil 8 is mounted along the outer circumference of the rotor 2, for example, in a distributed or concentrated manner. Thus, magnetic poles are formed on the stator 3 at equal intervals in the circumferential direction by the coils 8. In the rotary motor 1, the magnetic field of the stator 3 is sequentially switched by controlling the current in the coils 8, generating an attractive or repulsive force between the rotor 2 and the magnetic field of the stator 3. As a result, the rotor 2 rotates around the rotation axis Ax, driving the rotary motor 1.

[0031] In addition, such as Figure 2 As shown, a flange portion 7c extending circumferentially to both sides is formed at the front end of the tooth portion 7b located radially inward. In addition, at the front end of the tooth portion 7b, on the surface facing the outer periphery of the rotor 2, a groove 7d extending axially is formed to reduce torque pulsation.

[0032] The stator cover layer 9 is a resin layer covering the front end of the teeth 7b and each tooth slot of the stator core 7, and is formed of an insulating and non-magnetic resin material (e.g., thermosetting resin). It should be noted that the resin material of the stator cover layer 9 can be the same as or different from the resin material of the rotor cover layer 6.

[0033] like Figure 2 As shown, the stator cover layer 9 is arranged in a ring shape around the entire circumference of the stator 3 on the radially inner side. Specifically, on the radially inner side of the stator 3, the front end of the tooth 7b and the gap between adjacent teeth 7b are covered by the stator cover layer 9. Moreover, the inner circumferential surface of the stator 3 facing the outer periphery of the rotor 2 is formed into a uniform circle by the stator cover layer 9 when viewed from the axial direction.

[0034] Therefore, on the inner circumference of the stator 3, the recesses of the tooth grooves and the grooves 7d at the front end of the tooth portion 7b are filled with the resin material of the stator cover layer 9 and do not expose outwards, making the inner circumferential surface of the stator 3 uniform in the circumferential direction through the stator cover layer 9. In addition, by using the stator cover layer 9 to cover the entire circumference of the inner circumference of the stator 3, it is also possible to suppress the formation of resin burrs at the recesses of the tooth grooves.

[0035] Furthermore, the stator cover layer 9 forms a thin film covering the surface of the tooth portion 7b and the surface of the yoke portion 7a within the tooth slots. Thus, the stator cover layer 9 within the tooth slots functions to insulate the stator core 7 and the coil 8. Additionally, in each tooth slot, a gap 10 of a predetermined length is provided radially between the coil 8 and the yoke portion 7a. The gap 10 between the coil 8 and the yoke portion 7a extends axially and penetrates the stator 3, serving as a flow path for the refrigerant (e.g., oil) cooling the coil 8 to flow axially along the stator 3.

[0036] Figure 3 yesFigure 2 An enlarged view of the portion enclosed by the broken line in FIG. 7. Resin material of the stator cover layer 9 is filled in the slot 7d formed in the inner peripheral surface of the stator 3. In a cross section orthogonal to the axial direction, the slot 7d has a detent portion 7e formed so as to have a slot width w12 at a second position farther from the opening than a first position on the inner diameter side, which is larger than a slot width w11 (width in a direction orthogonal to the radial direction) at the first position (w11 < w12). Therefore, when an external force pulling out toward the inner diameter side is applied to the stator cover layer 9, the resin material of the detent portion 7e is caught at the first position where the slot width is narrower, and becomes a resistance to the force in the pulling-out direction. Therefore, by the detent portion 7e of the slot 7d, the stator cover layer 9 is difficult to peel off toward the inner peripheral side of the stator 3.

[0037] Likewise, resin material of the rotor cover layer 6 is filled in the slot 4a formed in the outer peripheral surface of the rotor 2. In a cross section orthogonal to the axial direction, the slot 4a has a detent portion 4b formed so as to have a slot width w22 at a second position farther from the opening than a first position on the outer diameter side, which is larger than a slot width w21 (width in a direction orthogonal to the radial direction) at the first position (w21 < w22). Therefore, when an external force pulling out toward the outer diameter side is applied to the rotor cover layer 6, the resin material of the detent portion 4b is caught at the first position where the slot width is narrower, and becomes a resistance to the force in the pulling-out direction. Therefore, by the detent portion 4b of the slot 4a, the rotor cover layer 6 is difficult to peel off toward the outer peripheral side of the rotor 2.

[0038] As described above, in the rotary electric machine 1 of the present embodiment, the stator 3 has the slot 7d formed in the inner peripheral surface facing the rotor 2 and extending in the axial direction intersecting the circumferential direction, and the stator cover layer 9 of resin covering the slot 7d. By forming the slot 7d, it is possible to suppress the torque ripple of the rotary electric machine 1, and by the stator cover layer 9, it is possible to make the inner peripheral surface of the stator 3 uniform in the circumferential direction, and suppress the wind loss caused by the slot 7d, the tooth slot.

[0039] In addition, the slot 7d includes the detent portion 7e formed so as to have a slot width w12 at a second position farther from the opening than a first position on the radial direction, which is larger than a slot width w11 at the first position. The detent portion 7e catches the resin material filled in the slot 7d and prevents the stator cover layer 9 from falling off. Thereby, it is possible to suppress the peeling of the stator cover layer 9 for reducing the wind loss.

[0040] In addition, the rotor 2 has the slot 4a formed in the outer peripheral surface facing the stator 3 and extending in the axial direction intersecting the circumferential direction, and the rotor cover layer 6 of resin covering the slot 4a. By forming the slot 4a, it is possible to suppress the torque ripple of the rotary electric machine 1, and by the rotor cover layer 6, it is possible to make the outer peripheral surface of the rotor 2 uniform in the circumferential direction, and suppress the wind loss caused by the slot 4a.

[0041] Further, the slot 4a includes a fall prevention portion 4b formed to have a slot width w22 larger than a slot width w21 of the first position, toward the radially inner side from the second position of the opening. The fall prevention portion 4b engages the resin material filled in the slot 4a to prevent the rotor cover layer 6 from falling off. Thus, peeling of the rotor cover layer 6 for reducing wind loss can be suppressed.

[0042] The present application is not limited to the above-described embodiments, and various modifications and design changes can be made within the scope of the present application.

[0043] For example, in the above-described embodiments, a case where the rotating electrical machine 1 is a motor is described, but the rotating electrical machine 1 can be a generator.

[0044] In the above-described embodiments, an example in which the slots each having the fall prevention portion are formed on the rotor 2 and the stator 3 is described. However, the slots each having the fall prevention portion can be formed on either the rotor 2 or the stator 3. Also, in the rotor 2 and the stator 3, the slots of a part of the circumferential direction can have the fall prevention portion, and it is not necessarily that all the slots have the fall prevention portion.

[0045] Further, the rotor cover layer 6 formed on the rotor 2 can be partially formed at the position of the slot 4a in the circumferential direction of the rotor core 4.

[0046] Further, the shape of the slot having the fall prevention portion is not limited to the above-described embodiments and Figure 3 For example, the cross-sectional shape of the slot orthogonal to the axial direction can be wedge-shaped in which the slot inner side is wide and the slot width is narrow as approaching the opening. Further, the cross-sectional shape of the slot can not necessarily be a shape symmetrical with respect to the radial line, and for example, a portion protruding toward the inner side can be formed on only one side of the slot.

[0047] Furthermore, the embodiments disclosed this time are to be considered as illustrative and not restrictive in all points. The scope of the present application is not shown by the above description but shown by the claims, and is intended to include all modifications equivalent in meaning and scope to the claims.

[0048] Explanation of Reference Numerals

[0049] 1 rotating electrical machine, 2 rotor, 3 stator, 4 rotor core, 4a slot, 4b fall prevention portion, 5 shaft, 6 rotor cover layer, 7 stator core, 7a yoke portion, 7b tooth portion, 7c flange portion, 7d slot, 7e fall prevention portion, 8 coil, 9 stator cover layer, 10 gap.

Claims

1. A rotary electric machine provided with a rotor and a stator, wherein the stator has: a slot portion formed on a circumferential surface facing the rotor and extending in a direction intersecting the circumferential direction; and a resin-made cover portion covering the slot portion, the slot portion includes an anti-extraction portion formed so as to have a slot width at a second position farther from an opening in a radial direction than a slot width at a first position, the anti-extraction portion engages a resin material filled in the slot portion to prevent the cover portion from falling off, the cover portion is formed annularly throughout the circumferential direction at a position inside in the radial direction of the stator, and at the position inside in the radial direction of the stator, a tip end portion of a tooth portion of the stator and a gap between adjacent tooth portions are covered by the cover portion, the cover portion covers surfaces of the tooth portion and a magnetic yoke portion of the stator in a film-like manner within a tooth slot of the stator to insulate a coil disposed within the tooth slot from the stator, the rotary electric machine further has a resin-made rotor cover portion covering a slot formed on an outer circumference of the rotor, the slot includes a rotor-side anti-extraction portion formed so as to have a slot width at an inner diameter side farther from the opening than a slot width at an outer diameter side, the rotor-side anti-extraction portion engages a resin material filled in the slot to prevent the rotor cover portion from falling off.

2. The rotary electric machine according to claim 1, wherein the slot portion is formed at a tip end of a tooth portion of the stator.

3. The rotary electric machine according to claim 1, wherein the tooth slot has a flow path for causing a refrigerant to flow to an outer diameter side of the coil.

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