Rotary electric machine

Abstract

To provide a rotary electric machine capable of suppressing breaking or cracking generated in a resin molded part of a stator.SOLUTION: A stator 21 includes a stator core 27 which has a yoke 39 and a plurality of teeth 43 and in which a plurality of electromagnetic steel sheets 37 is stacked, a coil 31 wound around each of the teeth 43, and a resin molded part 35 that molds the stator core 27 and the coil 31 with a resin. The teeth 43 each include a tooth body 46 around of which the coil 31 is wound, and a tooth tip 44. The resin molded part 35 includes a coil end coating part 55 molding the coil end 49, a slot filling part 57 molding the coil 31 in a slot 47, and tooth tip coating parts 58, 59 molding the tooth tip 44. An abutting member 33 is provided between the tooth tip 44 and the tooth tip coating parts 58, 59, the abutting member extending in the stacking direction of the electromagnetic steel sheets 37 and abutting against the tooth tip 44.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] A conventional rotating electric machine is disclosed in Patent Document 1. This rotating electric machine includes a rotating shaft, a rotor, a stator, and a housing that accommodates the rotating shaft, the rotor, and the stator.

[0003] The rotor is fixed to a rotating shaft and rotates integrally with the rotating shaft. The stator has a stator core disposed on the outside of the rotor, a coil, and a resin molded portion.

[0004] The stator core has a cylindrical yoke and a number of teeth protruding from the inner peripheral surface of the yoke toward the rotor. The stator core is configured by laminating a number of electromagnetic steel sheets so that slots are defined between adjacent teeth in the circumferential direction of the yoke.

[0005] The coils are wound around the teeth and have coil ends that protrude beyond the stator core in the lamination direction of the electromagnetic steel sheets.

[0006] The resin molded portion molds the stator core and the coils with resin. The resin molded portion has a coil end covering portion that molds the coil ends and a slot filling portion that molds the coils in the slots.

[0007] In this rotating electric machine, the coil is sealed inside a resin molded portion and fixed to the stator core by the resin molded portion. Also, in this rotating electric machine, heat generated in the coil is conducted to the stator core via the resin molded portion, thereby improving the heat dissipation efficiency of the rotating electric machine. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2013-66314 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, the conventional rotating electric machine described above has a problem in that cracks and fissures occur in the resin molded portion due to thermal expansion of the resin.

[0010] The present invention has been made in consideration of the above-mentioned conventional circumstances, and has an object to be achieved by providing a rotating electric machine capable of suppressing cracks and fissures in the resin molded portion of the stator. [Means for solving the problem]

[0011] The present inventors conducted extensive research to solve the above problems, and discovered that a large number of minute resin parts present in the minute gaps between the electromagnetic steel sheets stacked in the axial direction of the yoke at the contact area between the teeth and the resin molded part are involved in the cracks and fissures in the resin molded part.

[0012] That is, when the integrated stator core and coil are placed in a mold cavity and the resin molded part is formed by transfer molding or the like, a small amount of resin material penetrates into each minute gap between the axially stacked electromagnetic steel sheets. Therefore, in the resin molded part, a large number of minute resin parts interposed in each minute gap between the electromagnetic steel sheets are integrally formed in the portion that extends continuously in the axial direction and contacts the teeth. Then, an anchor effect is exerted by mechanical uneven engagement between the many axially stacked electromagnetic steel sheets and the many minute resin parts arranged at intervals in the axial direction.

[0013] As a result, in the resin molded portion, for example, the slot filling portion that extends continuously in the axial direction and contacts the teeth is restricted in its axial extension during thermal expansion by the anchor effect, making it difficult to extend in the axial direction. In contrast, in the resin molded portion, the coil end covering portion formed at the axial end of the stator core is less restricted in its extension during thermal expansion than the slot filling portion. As a result, stress concentration occurs at the boundary between the slot filling portion and the coil end covering portion, making it easy for cracks and fissures to occur starting from the boundary.

[0014] It is believed that such cracks or fissures in the resin molded portion are more likely to occur at the boundary between the tooth tip covering portion and the coil end covering portion when the tooth tip covering portion, which extends annularly in the axial direction and molds the radially inward tooth tips of each tooth, is formed integrally with the coil end covering portion and the slot filling portion in order to increase the contact area between the resin molded portion and the stator core and thereby improve the heat dissipation efficiency of the rotating electric machine.

[0015] The rotating electric machine of the present invention comprises: a rotating shaft; a rotor fixed to the rotary shaft and rotating integrally with the rotary shaft; a stator arranged on the outside of the rotor, the stator core having a cylindrical yoke and a plurality of teeth protruding from an inner peripheral surface of the yoke toward the rotor, the stator core being constructed by laminating a plurality of electromagnetic steel plates so that slots are defined between the teeth adjacent to each other in the circumferential direction of the yoke, a coil wound around the teeth, and a resin molded portion that molds the stator core and the coil with resin; a housing that accommodates the rotating shaft, the rotor, and the stator, The teeth each have a teeth main body around which the coil is wound, and a teeth tip portion provided on an opposite side of the teeth main body from the yoke, the coil has a coil end that protrudes beyond the stator core in a lamination direction of the electromagnetic steel sheets, the resin molded portion includes a coil end covering portion that molds the coil end, a slot filling portion that molds the coil in the slot, and a tooth tip covering portion that molds the tooth tip, The present invention is characterized in that abutting members are provided between the tooth tips and the tooth tip covering portions, the abutting members extending in the stacking direction and abutting against the tooth tips.

[0016] In the stator of the rotating electric machine of the present invention, coils are wound around the tooth main body portions of the teeth, and the slot filling portions of the resin molded portion mold the coils in the slots. The coil end covering portions of the resin molded portion mold the coil ends, and the tooth tip covering portions of the resin molded portion mold the tooth tips. Abutting members that come into contact with the tooth tips are provided between the tooth tips and the tooth tip covering portions.

[0017] With this configuration, the abutting member prevents contact between the tooth tips and the tooth tip coverings. Therefore, in the tooth tip coverings where contact with the tooth tips is prevented, minute resin portions interposed in the minute gaps between the electromagnetic steel sheets are not formed integrally, and the anchor effect due to the uneven engagement between the tooth tip coverings and the tooth tips is not exerted. As a result, the anchor effect is prevented from restricting the elongation of the tooth tip coverings in the stacking direction of the electromagnetic steel sheets when the resin thermally expands.

[0018] As a result, stress concentration caused by thermal expansion of the resin at the boundary between the tooth tip covering portion and the coil end covering portion is alleviated, making it possible to suppress the occurrence of cracks or fissures starting from this boundary portion.

[0019] Therefore, the rotating electric machine of the present invention can suppress cracks and fissures in the resin molded portion of the stator.

[0020] The tooth tip preferably has a tip outer peripheral surface extending in the stacking direction of the electromagnetic steel sheets, a tip inner peripheral surface extending in the stacking direction, and a tip side surface extending in the stacking direction. The tip outer peripheral surface preferably protrudes in the circumferential direction of the yoke further than the tooth main body, and suppresses the coil from protruding toward the rotor. The tip inner peripheral surface is preferably disposed on the inner side of the tip outer peripheral surface, and constitutes an end surface on the rotor side. The tip side surface preferably defines an opening of the slot in the radial direction of the yoke, and connects the tip outer peripheral surface and the tip inner peripheral surface. The abutting member preferably abuts against at least one of the tip outer peripheral surface, the tip inner peripheral surface, and the tip side surface.

[0021] In this case, the tooth tip covering portion that molds the tooth tips is prevented from contacting at least one of the outer peripheral surface, inner peripheral surface, and side surface of the tooth tips by the abutting member. Therefore, in the tooth tip covering portion that is prevented from contacting the tooth tips, the minute resin portions interposed in the minute gaps between the electromagnetic steel sheets are not integrally formed, and the anchor effect due to the uneven engagement between the tooth tip covering portion and the tooth tips is not exerted. As a result, the anchor effect is suppressed from restricting the elongation of the tooth tip covering portion in the stacking direction of the electromagnetic steel sheets when the resin thermally expands.

[0022] The contact member is preferably formed in an annular shape so as to contact inner circumferential surfaces of the tip ends of each of the plurality of teeth.

[0023] In this case, the annular abutment member prevents contact between the inner peripheral surface of the tip of each tooth and the tooth tip covering portion that molds the inner peripheral surface of the tip. Therefore, minute resin portions interposed in the minute gaps between the electromagnetic steel sheets are not integrally formed on the outer peripheral surface of the tooth tip covering portion that molds the inner peripheral surface of the tip of each tooth, and no anchor effect is produced by uneven engagement between the tooth tip covering portion and the inner peripheral surface of the tip of each tooth. As a result, the anchor effect is prevented from restricting the elongation of the tooth tip covering portion in the stacking direction of the electromagnetic steel sheets when the resin thermally expands.

[0024] The abutting member preferably has a bent piece that is bent so as to be engageable with the edge of the tooth tip, and the tooth tip covering portion preferably also covers the bent piece.

[0025] In this case, contact between the tooth tip covering portion and the edge of the tooth tip is prevented by the bent piece of the abutting member. Therefore, minute resin portions interposed in each minute gap between the electromagnetic steel sheets are not formed integrally with the tooth tip covering portion that covers the edge of the tooth tip, and an anchor effect due to uneven engagement is not exerted between the tooth tip covering portion and the edge of the tooth tip. As a result, the extension of the tooth tip covering portion in the stacking direction of the electromagnetic steel sheets is not restricted by the anchor effect when the resin thermally expands.

[0026] The contact member is preferably made of a resin that is softer than the resin used for molding.

[0027] In this case, the thermal stress in the resin molded portion can be alleviated by the soft contact member, which can further prevent the resin molded portion from cracking or breaking.

[0028] The contact member is preferably provided in contact only with the inner peripheral surface and the side surface of the tip portion. An insulating member that extends in the stacking direction and insulates the stator core from the coil is preferably provided between the stator core and the coil. The insulating member preferably extends from the outer peripheral surface of the tip portion of one of a pair of teeth that are adjacent to each other in the circumferential direction of the yoke with the inner peripheral surface of the yoke therebetween to the outer peripheral surface of the tip portion of the other of the pair of teeth.

[0029] In this case, the contact between the tooth tip covering portion of the resin molded portion and the inner peripheral surface and side surface of the tooth tip portion is prevented by the abutment member. Also, the contact between the slot filling portion of the resin molded portion and the outer peripheral surface of the tooth tip portion, the tooth main body portion, and the inner peripheral surface of the yoke is prevented by the insulating member. Therefore, in the tooth tip covering portion and the slot filling portion of the resin molded portion, the minute resin portions interposed in each minute gap between the electromagnetic steel sheets are not integrally formed, and the anchor effect due to the uneven engagement is not exerted between the tooth tip covering portion and the slot filling portion and the stator core. As a result, the elongation of the tooth tip covering portion and the slot filling portion in the stacking direction of the electromagnetic steel sheets is not restricted by the anchor effect when the resin thermally expands.

[0030] Each of the plurality of electromagnetic steel sheets constituting at least one of the yoke and the tooth body is preferably fixed in the stacking direction, and each of the plurality of electromagnetic steel sheets constituting the tooth tip is preferably not fixed in the stacking direction.

[0031] In this case, in at least one of the yoke and teeth main body portions in which the electromagnetic steel sheets are fixed in the stacking direction, the minute resin portions interposed in the minute gaps between the electromagnetic steel sheets are not integrally formed with the resin molded portion, and the extension of the slot filling portion in the stacking direction of the electromagnetic steel sheets is not restricted by the anchor effect during thermal expansion of the resin. Meanwhile, since the abutting member abuts the teeth tips in which the electromagnetic steel sheets are not fixed in the stacking direction, the restriction of the elongation of the teeth tip covering portion in the stacking direction of the electromagnetic steel sheets by the anchor effect during thermal expansion of the resin is suppressed. Effect of the Invention

[0032] The rotating electric machine of the present invention can suppress cracks and fissures in the resin molded portion of the stator. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a schematic diagram showing an electric compressor including a rotating electric machine according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of a stator in the rotating electric machine according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view of a stator core of the rotating electric machine according to the first embodiment. [Figure 4] FIG. 4 is a perspective view of the stator core, the bobbin, and the resin ring of the rotating electric machine according to the first embodiment. [Diagram 5] FIG. 5 is an axial cross-sectional view illustrating a schematic view of a stator of the rotating electric machine according to the first embodiment, which corresponds to the cross section taken along line AA in FIG. [Figure 6] FIG. 6 is a perspective view of a resin ring in the rotating electric machine according to the first embodiment. [Figure 7] FIG. 7 is a partial cross-sectional view of the rotating electric machine according to the first embodiment, taken along a direction perpendicular to the axial direction, which diagrammatically illustrates a resin ring and teeth. [Figure 8]FIG. 8 is a partial cross-sectional view perpendicular to the axial direction illustrating the rotating electric machine of the first embodiment, which diagrammatically shows the resin ring, teeth, bobbin, slot-received portion of the coil, slot filling portion of the resin molded portion, opening filling portion of the resin molded portion, and ring covering portion of the resin molded portion. [Figure 9] FIG. 9 is a partial cross-sectional view taken along a direction perpendicular to the axial direction and typically shows a resin ring having a bent piece and teeth in a rotating electric machine according to a second embodiment. [Figure 10] FIG. 10 is a partial cross-sectional view perpendicular to the axial direction illustrating a resin ring having a bent piece, teeth, a bobbin, a slot-received portion of the coil, a slot filling portion of the resin molded portion, an opening filling portion of the resin molded portion, and a ring covering portion of the resin molded portion in a rotating electric machine of the second embodiment. [Figure 11] FIG. 11 is a partial cross-sectional view perpendicular to the axial direction illustrating a rotating electric machine of the third embodiment, which diagrammatically shows the resin ring, teeth, bobbin, slot-received portion of the coil, slot filling portion of the resin molded portion, opening filling portion of the resin molded portion, and ring covering portion of the resin molded portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, first to third embodiments of the present invention will be described with reference to the drawings. An electric compressor including a rotating electric machine according to the first to third embodiments is mounted on a vehicle (not shown) and constitutes a refrigeration circuit of the vehicle.

[0035] Example 1 As shown in Fig. 1, the electric compressor equipped with the rotating electric machine of the first embodiment includes a housing 1, an electric motor 3, a compression mechanism 5, and an inverter 7. The electric motor 3 is an example of the "rotating electric machine" in the present invention. The housing 1 includes a cylindrical housing main body 11, a first cover 13, and a second cover 15.

[0036] In this embodiment, the front-rear direction of the electric compressor and the electric motor 3 is defined by the solid arrow shown in Fig. 1. This electric compressor is mounted on the vehicle in a position where its front is the front of the vehicle and its rear is the rear of the vehicle. Note that the position of the electric compressor can be changed as appropriate depending on the vehicle in which it is mounted.

[0037] As shown in FIG. 1, the housing body 11 has a rear wall 11a and a peripheral wall 11b. The rear wall 11a is located at the rear end of the housing body 11 and extends in the radial direction of the housing body 11. The peripheral wall 11b is connected to the rear wall 11a and extends forward from the rear wall 11a in the direction of the axis O. The rear wall 11a and the peripheral wall 11b form the housing body 11 into a substantially cylindrical shape with a bottom extending in the direction of the axis O. Here, the direction of the axis O is parallel to the front-rear direction of the electric motor 3. In the following description, when simply referring to the radial direction or the circumferential direction, it means the radial direction or the circumferential direction of the axis O, respectively. The direction of the axis O coincides with the axial direction of a yoke 39 described later and the lamination direction of the electromagnetic steel sheets 37 described later, and the radial direction or the circumferential direction of the axis O coincides with the radial direction or the circumferential direction of the yoke 39.

[0038] The rear wall 11a and the peripheral wall 11b define a motor chamber 17 inside the housing body 11. The motor chamber 17 is partitioned by the rear wall 11a and the peripheral wall 11b from the housing body 11 and, ultimately, from the outside of the electric compressor. Although not shown, a suction port communicating with the motor chamber 17 is formed in the peripheral wall 11b. Refrigerant gas is drawn into the motor chamber 17 through the suction port.

[0039] Furthermore, a plurality of bolt holes 11c are formed in the front end of the peripheral wall 11b. The bolt holes 11c extend rearward in the direction of the axis O. Note that FIG. 1 illustrates only one of the plurality of bolt holes 11c.

[0040] The first cover 13 is located in front of the housing body 11. The first cover 13 is fixed to the front end of the peripheral wall 11b by a plurality of bolts 13a inserted into the respective bolt holes 11c. A discharge chamber (not shown) is formed inside the first cover 13. Note that FIG. 1 illustrates one of the plurality of bolts 13a.

[0041] The second cover 15 is located at the rear of the housing body 11. The second cover 15 is fixed to the rear wall 11a by a plurality of bolts (not shown). The second cover 15 is formed in a cylindrical shape with a bottom, and forms an inverter chamber 19 between the second cover 15 and the rear wall 11a.

[0042] The inverter 7 is housed in an inverter chamber 19. The inverter 7 controls the operation of the electric motor 3. Note that the inverter 7 is a publicly available product, and detailed description of its configuration will be omitted.

[0043] Specifically, the electric motor 3 is an electric motor for a compressor. The electric motor 3 is provided in a motor chamber 17. The electric motor 3 is also electrically connected to an inverter .

[0044] The electric motor 3 includes a stator 21 , a rotating shaft 23 , and a rotor 25 .

[0045] The stator 21 includes a stator core 27 shown in Figs. 3 and 4, a bobbin 29 shown in Figs. 4, 5 and 8, a coil 31 shown in Figs. 1, 5 and 8, a resin ring 33 shown in Figs. 4 to 8, and a resin molded portion 35 shown in Figs. 1, 2, 5 and 8. The bobbin 29 is an example of the "insulating member" in the present invention. The resin ring 33 is an example of the "abutment member" in the present invention. The stator 21 is fixed to the peripheral wall 11b of the housing body 11 by shrink fitting.

[0046] As shown in FIG. 1, the stator core 27 is formed by stacking a number of electromagnetic steel sheets 37 in the direction of the axis O. As shown in FIG. 3 and FIG. 4, the stator core 27 has a cylindrical yoke 39 and six teeth 43. The outer peripheral edge portions 41 of the yoke 39 of each electromagnetic steel sheet 37 are welded to each other at welded portions 42 to be integrated into the stator core 27. The electromagnetic steel sheets 37 may be fixed and integrated by crimping. The welded portion 42 is one portion in the circumferential direction of the yoke 39, and extends over the entire yoke 39 in the direction of the axis O from the front end to the rear end of the yoke 39. In the portions of each electromagnetic steel sheet 37 other than the outer peripheral edge portions 41 of the yoke 39, the electromagnetic steel sheets 37 adjacent to each other in the direction of the axis O are merely stacked and are not fixed to each other. That is, in stator core 27, each of the plurality of electromagnetic steel sheets 37 constituting yoke 39 is fixed in the axial direction O, while each of the plurality of electromagnetic steel sheets 37 constituting teeth 43 is not fixed in the axial direction O.

[0047] The yoke 39 has a cylindrical shape centered on an axis O and extending in the direction of the axis O, that is, in the front-rear direction.

[0048] The teeth 43 have the same shape and are arranged at equal intervals in the circumferential direction on the yoke 39. Each tooth 43 is integral with the yoke 39 and extends radially inward from an inner peripheral surface 39a of the yoke 39 toward the center of the stator core 27, i.e., the axis O. Each tooth 43 extends over the entire yoke 39 in the direction of the axis O, from the front end to the rear end of the stator core 27.

[0049] As shown in FIGS. 3 and 7, each tooth 43 has a tooth main body 46 and a tooth tip portion 44.

[0050] The tooth main body 46 extends radially inward from the yoke inner peripheral surface 39a of the yoke 39. The tooth main body 46 extends radially with a substantially constant circumferential width. The tooth main body 46 has main body side surfaces 46a on both circumferential sides. The coil 31 is wound around the tooth main body 46 of the tooth 43.

[0051] The tooth tip portion 44 is provided on the opposite side of the yoke 39 in the radial direction, with the tooth main body portion 46 sandwiched therebetween. The tooth tip portion 44 has a flange portion 45 that protrudes in an arc shape on both sides in the circumferential direction. The flange portion 45 protrudes in the circumferential direction further than the tooth main body portion 46. The tooth tip portion 44 has a tip portion inner peripheral surface 43a that extends in the axis O direction and faces radially inward, a flange portion side surface 45a that extends in the axis O direction and faces circumferentially, and a flange portion outer peripheral surface 45b that extends in the axis O direction and faces radially outward. The flange portion side surface 45a is an example of the "tip portion side surface" in the present invention. The flange portion outer peripheral surface 45b is an example of the "tip portion outer peripheral surface" in the present invention.

[0052] The flange outer peripheral surface 45b protrudes in the circumferential direction beyond the tooth main body 46, and prevents a slot-received portion 51 (described later) from protruding toward the rotor 25. The tip inner peripheral surface 43a is located on the inner peripheral side of the flange outer peripheral surface 45b, and constitutes the end face of the tooth 43 on the rotor 25 side. The tip inner peripheral surface 43a forms an arc surface. The flange side surface 45a radially connects the flange outer peripheral surface 45b and the tip inner peripheral surface 43a. A pair of flange side surfaces 45a adjacent in the circumferential direction define an opening 47b (see FIG. 3) of a slot 47 (described later) on the radially inner side of the slot 47.

[0053] As shown in Figs. 3 and 4, six slots 47 are formed between adjacent teeth 43 in the circumferential direction. The slots 47 are arranged at equal intervals in the circumferential direction. The slots 47 have the same shape and extend from the front end to the rear end of the yoke 39 in the direction of the axis O. As shown in Fig. 7, both circumferential side surfaces of each tooth 43 form slot partition surfaces 47a that partition the slots 47. That is, the main body side surface 46a, the flange outer peripheral surface 45b, the flange side surface 45a, and the yoke inner peripheral surface 39a form the slot partition surface 47a.

[0054] 4, 5 and 8, the bobbin 29 covers the flange outer peripheral surface 45b, the main body side surface 46a, the flange outer peripheral surface 45b and the yoke inner peripheral surface 39a, which are the portions of the slot partition surface 47a of each tooth 43 other than the flange side surface 45a. In other words, the bobbin 29 extends from the flange outer peripheral surface 45b of one tooth 43 to the flange outer peripheral surface 45b of the other tooth 43, sandwiching the main body side surface 46a of one tooth 43, the yoke inner peripheral surface 39a and the main body side surface 46a of the other tooth 43, in a pair of teeth 43 adjacent in the circumferential direction with the yoke inner peripheral surface 39a therebetween. The bobbin 29 also covers both end surfaces of each tooth 43 in the direction of the axis O. The bobbin 29 is made of a resin having electrical insulation and heat resistance, specifically, PPS (polyphenylene sulfide).

[0055] 1, 5 and 8, the coil 31 is provided by winding a conductive wire having an insulating coating around each of the teeth 43. The coil 31 has a pair of coil ends 49 and six slot-accommodated portions 51. Each coil end 49 protrudes from the stator core 27 in the direction of the axis O. Each slot-accommodated portion 51 is accommodated in a slot 47.

[0056] The resin ring 33 is made of resin having electrical insulation and heat resistance, and specifically, is made of PPS (polyphenylene sulfide).

[0057] As shown in Fig. 5, the resin ring 33 extends annularly in the direction of the axis O. The resin ring 33 extends over the entire teeth 43 in the direction of the axis O, from the front end to the rear end of the stator core 27. As shown in Figs. 4, 5, 7 and 8, the ring outer peripheral surface 33a of the resin ring 33 faces the radially inner tip inner peripheral surfaces 43a of each tooth 43. The ring outer peripheral surface 33a of the resin ring 33 abuts against the tip inner peripheral surfaces 43a of each tooth 43.

[0058] 4 to 6, the resin ring 33 has six protrusions 53. Each protrusion 53 protrudes radially outward in a substantially semicircular shape from one end in the direction of the axis O of the ring outer circumferential surface 33a of the resin ring 33. Each protrusion 53 abuts against one end face in the direction of the axis O of the tooth tip portion 44 on the radially inner side of each tooth 43.

[0059] The resin molded portion 35 is made of a resin having electrical insulation and heat resistance, specifically, an epoxy resin with a ceramic powder filler mixed in. The Young's modulus of the resin ring 33 is lower than that of the resin molded portion 35, and the resin ring 33 is softer than the resin molded portion 35.

[0060] 1, 2, 5 and 8, resin molded portion 35 covers stator core 27 and coils 31. Resin molded portion 35 has a pair of coil end covering portions 55, six slot filling portions 57, six opening filling portions 58, and a ring covering portion 59. Each opening filling portion 58 and ring covering portion 59 constitute a "tooth tip covering portion" of the present invention that molds tooth tips 44.

[0061] Each coil end covering portion 55 is molded to cover each coil end 49. Each slot filling portion 57 is filled in each slot 47 to mold each slot accommodated portion 51 and cover each slot accommodated portion 51. Each opening filling portion 58 is filled in the opening 47b of the slot 47 to close the opening 47b. The ring covering portion 59 extends in an annular shape in the direction of the axis O and is molded to cover the ring inner peripheral surface 33b of the resin ring 33. The outer peripheral surface 59a of the ring covering portion 59 and the ring inner peripheral surface 33b of the resin ring 33 are in contact with each other. Each coil end covering portion 55 is integrally formed with the ring covering portion 59, each slot filling portion 57, and each opening filling portion 58. Each opening filling portion 58 and each slot filling portion 57 are integrally formed.

[0062] The resin molded portion 35 can be molded by transfer molding after placing an integral part of the stator core 27, the bobbin 29, the coil 31, and the resin ring 33 in a cavity of a mold. In detail, after the bobbin 29 is attached to the stator core 27, the coil 31 is wound around the teeth 43. Then, the resin ring 33 is set radially inward of the stator core 27. At this time, each protrusion 53 of the resin ring 33 is abutted against one end face of the stator core 27 in the axial center O direction, and the resin ring 33 is held against the stator core 27. This integral part of the stator core 27, the bobbin 29, the coil 31, and the resin ring 33 is placed in the cavity of a mold. Then, a resin material is injected into the cavity from one side in the axial center O direction, and the resin molded portion 35 is molded by transfer molding.

[0063] When the resin material is injected in this transfer molding, each protrusion 53 of the resin ring 33 abuts on one end face of the stator core 27 in the axial center O direction, so that the resin ring 33 can be held at a predetermined position relative to the stator core 27. The resin ring 33 is disposed radially inward of the stator core 27, and the ring outer circumferential surface 33a of the resin ring 33 abuts against the tip inner circumferential surface 43a of each tooth 43. This prevents the resin material from penetrating between the ring outer circumferential surface 33a of the resin ring 33 and the tip inner circumferential surface 43a of each tooth 43, and also prevents the resin material from penetrating into each minute gap between the electromagnetic steel sheets 37. As a result, the minute resin portions interposed in each minute gap between the electromagnetic steel sheets 37 are not formed integrally with the outer circumferential surface 59a of the ring covering portion 59.

[0064] As shown in Fig. 1, the rotor 25 is disposed inside the stator 21. The rotor 25 has a cylindrical shape extending in the direction of the axis O. A permanent magnet (not shown) is provided in the rotor 25. The rotating shaft 23 is fixed to the rotor 25 by shrink fitting, and the rotor 25 and the rotating shaft 23 are integrated together. When a current flows through the coil 31, the rotor 25 can rotate around the axis O together with the rotating shaft 23.

[0065] A known scroll type compression mechanism is used as the compression mechanism 5. The compression mechanism 5 is accommodated in the housing body 11. The compression mechanism 5 has a fixed scroll fixed to the inner circumferential surface of the peripheral wall 11b in front of the motor chamber 17 in the housing body 11, and a movable scroll disposed opposite the fixed scroll and rotatable by a rotating shaft 23. The fixed scroll and the movable scroll are engaged with each other to form a compression chamber between them for compressing the refrigerant gas. The fixed scroll, the movable scroll, and the compression chamber are all omitted from the illustration.

[0066] In the stator 21 of the electric motor 3 included in this electric compressor, the coil 31 is wound around the tooth main body 46, the coil end covering portion 55 of the resin molded portion 35 molds the coil end 49, and the slot filling portion 57 of the resin molded portion 35 molds the slot accommodated portion 51. In addition, the ring covering portion 59 and the opening filling portion 58 serving as the tooth tip covering portion of the resin molded portion 35 mold the tooth tip portion 44. A resin ring 33 that abuts against the tooth tip portion 44 is provided between the tooth tip portion 44 and the ring covering portion 59.

[0067] More specifically, a resin ring 33 is disposed inside the stator core 27, and a ring outer peripheral surface 33a of the resin ring 33 faces and abuts against a radially inner tip inner peripheral surface 43a of each tooth 43. A ring inner peripheral surface 33b of the resin ring 33 is covered with a ring covering portion 59 of the resin molded portion 35. That is, the resin ring 33 extending over the entire stator core 27 in the direction of the axis O is interposed between the tip inner peripheral surface 43a of each tooth 43 and the ring covering portion 59. Therefore, the resin ring 33 prevents contact between the tip inner peripheral surface 43a and the ring covering portion 59.

[0068] For this reason, as described above, the minute resin portions interposed in the minute gaps between the electromagnetic steel sheets 37 are not formed integrally with the outer peripheral surface 59a of the ring covering portion 59, and no anchor effect due to concave-convex engagement is produced between the ring covering portion 59 and the inner peripheral surfaces 43a of the tip portions of the teeth 43. As a result, when the resin molded portion 35 thermally expands due to heat from the coil 31, the extension of the ring covering portion 59 in the direction of the axis O is not restricted by the anchor effect.

[0069] As a result, stress concentration caused by thermal expansion of the resin at the boundary S (see Figure 5) between the ring covering portion 59 and the coil end covering portion 55 is alleviated, thereby suppressing the occurrence of cracks or fissures starting from this boundary S.

[0070] In addition, in this electric motor 3, the slot partition surface 47a of each tooth 43 is covered with the bobbin 29 except for the flange side surface 45a of the flange 45. The bobbin 29 prevents the slot partition surface 47a covered with the bobbin 29 from contacting the slot filling portion 57, so that the minute resin portions present in the minute gaps between the electromagnetic steel sheets 37 are prevented from being integrally formed with the slot filling portion 57. Therefore, the anchor effect due to the uneven engagement between the electromagnetic steel sheet 37 and the minute resin portions is not exerted between the slot partition surface 47a covered with the bobbin 29 and the slot filling portion 57. As a result, the axial extension of the slot filling portion 57 during thermal expansion of the resin is not restricted by the anchor effect generated between the slot partition surface 47a covered with the bobbin 29 and the slot filling portion 57.

[0071] This reduces the stress concentration that occurs at the boundary between the coil end covering portion 55 and the slot filling portion 57 due to thermal expansion of the resin, thereby suppressing the occurrence of cracks or fissures that start at this boundary.

[0072] Furthermore, in this electric motor 3, the resin ring 33 is softer than the resin molded portion 35. Therefore, the thermal stress in the resin molded portion 35 can be alleviated by the soft resin ring 33. This makes it possible to further suppress the occurrence of cracks or fractures in the resin molded portion 35.

[0073] Therefore, in the electric motor 3, and in turn in the electric compressor of the first embodiment including the electric motor 3, cracks or cracks in the resin molded portion 35 of the stator 21 can be suppressed.

[0074] In addition, the heat generated in the coil 31 can be conducted to each tooth 43 via the coil end covering portion 55, the ring covering portion 59, and the resin ring 33, which can contribute to improving the heat dissipation efficiency of the electric motor 3.

[0075] Example 2 The electric compressor of the second embodiment includes an electric motor 3A shown in Fig. 10 instead of the electric motor 3. The electric motor 3A is also an example of the "rotating electric machine" of the present invention. In the electric motor 3A, a resin ring 33A in a stator 21 has twelve bent pieces 61.

[0076] As shown in Fig. 9, the resin ring 33A has six pairs of bent pieces 61 that protrude radially outward from the ring outer peripheral surface 33a of the resin ring 33A. Each bent piece 61 faces the circumferential flange side surface 45a of the flange 45. Each bent piece 61 abuts against the flange side surface 45a of the flange 45. Each bent piece 61 extends over the entire stator core 27 in the axial direction O. Each bent piece 61 engages with an edge 44a of the tooth tip portion 44. The edge 44a connects the flange side surface 45a and the tip portion inner peripheral surface 43a.

[0077] As shown in FIG. 10, each opening filling portion 58 constituting a part of the tooth tip covering portion covers each bent piece 61 entirely.

[0078] In this electric motor 3A, a bent piece 61 of the resin ring 33A is interposed between the entire flange side surface 45a, including the edges 44a of the tooth tips 44, and the opening filling portion 58. Therefore, the bent piece 61 prevents contact between the flange side surface 45a, including the edges 44a, and the opening filling portion 58, so that the minute resin portions interposed in the minute gaps between the electromagnetic steel sheets 37 are prevented from being formed integrally with the opening filling portion 58. Therefore, an anchor effect due to the uneven engagement between the electromagnetic steel sheets 37 and the minute resin portions is not exerted between the opening filling portion 58 and the flange side surface 45a, including the edges 44a, so that the elongation of the opening filling portion 58 in the direction of the axis O is not restricted by the anchor effect during thermal expansion of the resin.

[0079] Therefore, stress concentration caused by thermal expansion of the resin at the boundary between the opening filling portion 58 and the coil end covering portion 55 is alleviated, making it possible to suppress the occurrence of cracks or fissures starting from this boundary.

[0080] The other configurations and effects are the same as those of the first embodiment.

[0081] Example 3 The electric compressor of the third embodiment includes an electric motor 3B shown in Fig. 11 instead of the electric motor 3. The electric motor 3B is also an example of the "rotating electric machine" of the present invention.

[0082] In this electric motor 3B, a gap 63 is formed between both entire circumferential flange side surfaces 45a of each flange 45 of each tooth 43 and the opening filling portion 58. Each gap 63 extends entirely in the axial direction O of the stator core 27.

[0083] The formation of void 63 is not particularly limited. For example, void 63 can be formed by molding resin molded part 35 with a wax part or core made of wax placed in the portion of the mold cavity where void 63 is to be formed, and then melting and expelling the wax part or removing the core.

[0084] In this electric motor 3B, a gap 63 is interposed between the entire flange side surface 45a of the flange 45 of each tooth 43 and the opening filling portion 58. For this reason, the gap 63 prevents contact between the opening filling portion 58 and the flange side surface 45a of the flange 45, and therefore prevents the minute resin portions interposed in the minute gaps between the electromagnetic steel sheets 37 from being formed integrally with the opening filling portion 58. For this reason, an anchor effect due to the uneven engagement between the electromagnetic steel sheets 37 and the minute resin portions is not exerted between the opening filling portion 58 and the flange side surface 45a of the flange 45, and therefore the elongation of the opening filling portion 58 in the direction of the axis O is not restricted by the anchor effect during thermal expansion of the resin.

[0085] Therefore, stress concentration caused by thermal expansion of the resin at the boundary between the opening filling portion 58 and the coil end covering portion 55 is alleviated, making it possible to suppress the occurrence of cracks or fissures starting from this boundary.

[0086] The other configurations and effects are the same as those of the first embodiment.

[0087] In the above, the present invention has been described based on Examples 1 to 3. However, the present invention is not limited to the above Examples 1 to 3, and it goes without saying that the present invention can be modified and applied as appropriate without departing from the spirit of the present invention.

[0088] For example, in the first embodiment, the abutting member is brought into contact with the tip inner peripheral surface 43a of the tooth tip portion 44, and in the second embodiment, the abutting member is brought into contact with the tip inner peripheral surface 43a of the tooth tip portion 44 and the flange side surface 45a as the tip side surface, but the present invention is not limited thereto. For example, the abutting member may be brought into contact with at least one of the tip side surface and the tip outer peripheral surface of the tooth tip portion 44, or the abutting member may be brought into contact with all of the tip inner peripheral surface 43a, the tip side surface, and the tip outer peripheral surface of the tooth tip portion 44. When the abutting member is brought into contact with the tip side surface and / or the tip outer peripheral surface of the tooth tip portion 44, the abutting member may be formed integrally with the bobbin attached to the tooth 43, for example.

[0089] In the second embodiment, a bent piece 61 integral with the resin ring 33A that abuts against the tip inner peripheral surface 43a is engaged with an edge 44a that connects the tip inner peripheral surface 43a and the flange side surface 45a as the tip side surface, and the bent piece 61 abuts against the flange side surface 45a, but the present invention is not limited to this. For example, a bent piece integral with an abutment member that abuts against one of the tip side surface and the tip outer peripheral surface may be engaged with an edge that connects the tip side surface and the tip outer peripheral surface, and the bent piece may abut against the other of the tip side surface and the tip outer peripheral surface.

[0090] In the first to third embodiments, the outer peripheral edge portions 41 of the yokes 39 of the electromagnetic steel sheets 37 are welded to be integrated into the stator core 27, but the present invention is not limited to this. For example, the stator core 27 may be integrated by welding the teeth main bodies 46 in addition to or instead of welding the outer peripheral edge portions 41 of the yokes 39.

[0091] The resin ring 33 or 33A may have a Young's modulus equal to or greater than that of the resin molded portion .

[0092] Moreover, the bent piece 61 may partially cover the flange side surface 45a of the flange 45. Similarly, the gap 63 may be formed partially with respect to the flange side surface 45a of the flange 45.

[0093] Furthermore, as the compression mechanism 5, in addition to a vane type compression mechanism or a swash plate type compression mechanism, a centrifugal type compression mechanism or the like may be adopted.

[0094] Furthermore, the compression mechanism 5 may compress a fluid other than a refrigerant gas, such as air or hydrogen to be pumped to a fuel cell, that is, the compression mechanism 5 may be used for a fuel cell vehicle.

[0095] The following technical ideas can be extracted from the disclosure of the specification, drawings, etc.

[0096] (Appendix 1) A rotation axis; a rotor fixed to the rotary shaft and rotating integrally with the rotary shaft; a stator arranged on the outside of the rotor, the stator core having a cylindrical yoke and a plurality of teeth protruding from an inner peripheral surface of the yoke toward the rotor, the stator core being constructed by laminating a plurality of electromagnetic steel plates so that slots are defined between the teeth adjacent to each other in the circumferential direction of the yoke, a coil wound around the teeth, and a resin molded portion that molds the stator core and the coil with resin; a housing that accommodates the rotating shaft, the rotor, and the stator, The teeth each have a teeth main body around which the coil is wound, and a teeth tip portion provided on an opposite side of the teeth main body from the yoke, the coil has a coil end that protrudes beyond the stator core in a lamination direction of the electromagnetic steel sheets, the resin molded portion includes a coil end covering portion that molds the coil end, a slot filling portion that molds the coil in the slot, and a tooth tip covering portion that molds the tooth tip, a contact member extending in the stacking direction and contacting the tooth tip portion is provided between the tooth tip portion and the tooth tip covering portion, the contact member being in contact with the tooth tip portion.

[0097] (Appendix 2) The tip portion of the teeth is a tip outer peripheral surface extending in the stacking direction and protruding in the circumferential direction beyond the tooth main body portion and preventing the coil from protruding toward the rotor side; a tip portion inner circumferential surface extending in the stacking direction, disposed radially inward relative to the tip portion outer circumferential surface, and constituting the rotor-side end surface; a tip portion side surface extending in the stacking direction, defining an opening of the slot in a radial direction of the yoke, and connecting the tip portion outer peripheral surface and the tip portion inner peripheral surface; 2. The rotating electric machine according to claim 1, wherein the contact member contacts at least one of the tip outer peripheral surface, the tip inner peripheral surface, and the tip side surface.

[0098] (Appendix 3) 3. The rotating electric machine according to claim 2, wherein the contact member is formed in an annular shape so as to contact inner circumferential surfaces of each of the tip ends of the teeth.

[0099] (Appendix 4) the abutment member has a bent piece that is bent so as to be engaged with an edge of the tip portion of the tooth, 4. The rotating electric machine according to claim 1, wherein the teeth tip covering portion also covers the bent piece.

[0100] (Appendix 5) 5. The rotating electric machine according to claim 1, wherein the contact member is made of a resin softer than the resin used for molding.

[0101] (Appendix 6) The contact member is provided so as to contact only the inner peripheral surface of the tip portion and the side surface of the tip portion, an insulating member is provided between the stator core and the coil, the insulating member extending in the stacking direction and insulating the stator core from the coil; 4. The rotating electric machine according to claim 2, wherein the insulating member extends from the outer peripheral surface of the tip of one of a pair of teeth that are adjacent to each other in the circumferential direction with the inner peripheral surface of the yoke therebetween to the outer peripheral surface of the tip of the other of the pair of teeth.

[0102] (Appendix 7) The contact member is provided so as to contact only the inner peripheral surface of the tip portion and the side surface of the tip portion, an insulating member is provided between the stator core and the coil, the insulating member extending in the stacking direction and insulating the stator core from the coil; The rotating electric machine according to Appendix 4 which cites Appendix 2 or 3, Appendix 5 which cites Appendix 2 or 3, or Appendix 5 which cites Appendix 3 and 4, wherein the insulating member extends from the outer peripheral surface of the tip of one of a pair of teeth which are adjacent in the circumferential direction with the yoke inner peripheral surface therebetween to the outer peripheral surface of the tip of the other of the pair of teeth.

[0103] (Appendix 8) A rotating electric machine as described in any one of appendixes 1 to 7, wherein each of the plurality of electromagnetic steel plates constituting at least one of the yoke and the tooth main body portion is fixed in the stacking direction, and each of the plurality of electromagnetic steel plates constituting the tooth tip portion is not fixed in the stacking direction. [Industrial Applicability]

[0104] The present invention can be used in electrically-driven devices such as vehicle electric compressors. [Explanation of symbols]

[0105] 1. Housing 3, 3A, 3B...Electric motor (rotating electric machine) 21...Stator 23...Rotation axis 25…Rotor 27…Stator core 29...Bobbin (insulating material) 31…Coil 33...Resin ring (contact member) 35…Resin molded part 37...Electromagnetic steel plate 39…York 39a…Inner surface of yoke 43…Teeth 43a...Tip inner peripheral surface 44…Tip of teeth 44a…Edge 45a... Flange side (tip side) 45b...Outer circumferential surface of the collar (outer circumferential surface of the tip) 46…Teeth body 47…Slot 47b…Aperture 49…Coil end 55...Coil end coating 57…Slot filling section 58...Opening filling part (tooth tip covering part) 59...Ring coating (teeth tip coating) 61...Bending piece

Claims

1. A rotation axis; a rotor fixed to the rotary shaft and rotating integrally with the rotary shaft; a stator arranged on the outside of the rotor, the stator core having a cylindrical yoke and a plurality of teeth protruding from an inner peripheral surface of the yoke toward the rotor, the stator core being constructed by laminating a plurality of electromagnetic steel plates so that slots are defined between the teeth adjacent to each other in the circumferential direction of the yoke, a coil wound around the teeth, and a resin molded portion that molds the stator core and the coil with resin; a housing that accommodates the rotating shaft, the rotor, and the stator, The teeth each have a teeth main body around which the coil is wound, and a teeth tip portion provided on an opposite side of the teeth main body from the yoke, the coil has a coil end that protrudes beyond the stator core in a lamination direction of the electromagnetic steel sheets, the resin molded portion includes a coil end covering portion that molds the coil end, a slot filling portion that molds the coil in the slot, and a tooth tip covering portion that molds the tooth tip, a contact member extending in the stacking direction and contacting the tooth tip portion is provided between the tooth tip portion and the tooth tip covering portion, the contact member being in contact with the tooth tip portion.

2. The tooth tip portion is a tip outer peripheral surface extending in the stacking direction and protruding in the circumferential direction beyond the tooth main body portion and preventing the coil from protruding toward the rotor side; a tip portion inner circumferential surface extending in the stacking direction, disposed radially inward relative to the tip portion outer circumferential surface, and constituting the rotor-side end surface; a tip portion side surface extending in the stacking direction, defining an opening of the slot in a radial direction of the yoke, and connecting the tip portion outer peripheral surface and the tip portion inner peripheral surface; The rotating electric machine according to claim 1 , wherein the contact member contacts at least one of the outer peripheral surface of the tip portion, the inner peripheral surface of the tip portion, and the side surface of the tip portion.

3. 3. The rotating electric machine according to claim 2, wherein the contact member is formed in an annular shape so as to contact inner circumferential surfaces of the tip ends of each of the plurality of teeth.

4. the abutment member has a bent piece that is bent so as to be engaged with an edge of the tip portion of the tooth, 4. The rotating electric machine according to claim 1, wherein the tooth tip covering portion also covers the bent piece.

5. 4. The rotating electric machine according to claim 1, wherein the contact member is made of a resin that is softer than the resin that is molded.

6. The contact member is provided so as to contact only the inner peripheral surface of the tip portion and the side surface of the tip portion, an insulating member is provided between the stator core and the coil, the insulating member extending in the stacking direction and insulating the stator core from the coil; 4. A rotating electric machine as described in claim 2 or 3, wherein the insulating member extends from the outer peripheral surface of the tip portion of one of a pair of teeth adjacent to each other in the circumferential direction with the inner peripheral surface of the yoke sandwiched therebetween to the outer peripheral surface of the tip portion of the other of the pair of teeth.

7. A rotating electric machine as claimed in any one of claims 1 to 3, wherein each of the plurality of electromagnetic steel plates constituting at least one of the yoke and the tooth main body portion is fixed in the stacking direction, and each of the plurality of electromagnetic steel plates constituting the tooth tip portion is not fixed in the stacking direction.

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