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 of a rotary electric machine 3 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. A gap 61 is provided between the tooth tip 44 and the tooth tip coating parts 58, 59, the gap extending in the stacking direction of the electromagnetic steel sheets 37.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 constructed 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 the resin molded portion is susceptible to cracks and fissures caused by 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, A gap is provided between the tooth tip portions and the tooth tip covering portions, the gap extending in the stacking direction.

[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. In addition, 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. A gap is provided between the tooth tips and the tooth tip covering portions.

[0017] With this configuration, the gap 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 no anchor effect is produced between the tooth tip coverings and the tooth tips due to uneven engagement. 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 located on the inner side of the tip outer peripheral surface and constitutes the end surface on the rotor side. The tip side surface preferably defines the opening of the slot in the radial direction of the yoke and connects the tip outer peripheral surface and the tip inner peripheral surface. And, it is preferable that a gap is provided at least one of between the tip inner peripheral surface and the tooth tip covering, and between the tip side surface and the tooth tip covering.

[0021] In this case, the gap prevents the teeth tip covering parts that mold the teeth tips from contacting at least one of the tip inner peripheral surface and the tip side surface of the teeth tips. Therefore, in the teeth tip covering parts that are prevented from contacting the teeth tips, the minute resin parts that are 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 teeth tip covering parts and the teeth tips is not exerted. As a result, the anchor effect is suppressed from restricting the elongation of the teeth tip covering parts in the stacking direction of the electromagnetic steel sheets when the resin thermally expands.

[0022] An insulating member is preferably provided between the stator core and the coil, extending in the stacking direction and insulating the stator core and the coil. The insulating member preferably extends, sandwiching the yoke inner peripheral surface, from the outer peripheral surface of the tip of one of a pair of teeth adjacent to each other in the circumferential direction of the yoke to the outer peripheral surface of the tip of the other of the pair of teeth.

[0023] In this case, the insulating member prevents contact between the slot filling portion of the resin molded portion and the outer peripheral surface of the tip portion of the tooth, the tooth body portion, and the inner peripheral surface of the yoke. Therefore, even in the slot filling portion of the resin molded portion, 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 slot filling portion and the stator core is not exerted. As a result, the elongation of the slot filling portion in the stacking direction of the electromagnetic steel sheets is suppressed from being restricted by the anchor effect when the resin thermally expands.

[0024] 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.

[0025] 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 a gap is provided between the teeth tips and the teeth tip covering portions in which the electromagnetic steel sheets are not fixed in the stacking direction, the extension of the teeth tip covering portions in the stacking direction of the electromagnetic steel sheets is prevented from being restricted by the anchor effect during thermal expansion of the resin. Effect of the Invention

[0026] 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]

[0027] [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 a stator core and a bobbin in 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 partial cross-sectional view perpendicular to the axial direction illustrating the rotating electric machine of the first embodiment, which diagrammatically shows the teeth, the bobbin, the slot-received portions of the coils, the slot-filled portions of the resin molded portion, the opening-filled portions of the resin molded portion, and the ring-shaped covering portions of the resin molded portion. [Figure 7] FIG. 7 is a partial cross-sectional view perpendicular to the axial direction illustrating a rotating electric machine of the second embodiment, which diagrammatically shows the teeth, the bobbin, the slot-received portions of the coil, the slot-filled portions of the resin molded portion, the opening-filled portions of the resin molded portion, and the ring-shaped covering portions of the resin molded portion. [Figure 8] FIG. 8 is a partial cross-sectional view perpendicular to the axial direction illustrating a rotating electric machine of the third embodiment, which diagrammatically shows the teeth, the bobbin, the slot-received portions of the coil, the slot-filled portions of the resin molded portion, the opening-filled portions of the resin molded portion, and the ring-shaped covering portions of the resin molded portion. [Figure 9] FIG. 9 is a partial cross-sectional view perpendicular to the axial direction illustrating a rotating electric machine of the fourth embodiment, which diagrammatically shows the teeth, the bobbin, the slot-received portions of the coil, the slot-filled portions of the resin molded portion, the opening-filled portions of the resin molded portion, and the ring-shaped covering portions of the resin molded portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, first to fourth embodiments of the present invention will be described with reference to the drawings. An electric compressor including a rotating electric machine according to any one of the first to fourth embodiments is mounted on a vehicle (not shown) and constitutes a refrigeration circuit of the vehicle.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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 .

[0038] The electric motor 3 includes a stator 21 , a rotating shaft 23 , and a rotor 25 .

[0039] The stator 21 includes a stator core 27 shown in Figures 3 and 4, a bobbin 29 shown in Figures 4 to 6, a coil 31 shown in Figures 1, 5 and 6, and a resin molded portion 35 shown in Figures 1, 2, 5 and 6. The bobbin 29 is an example of the "insulating member" in the present invention. The stator 21 is fixed to the peripheral wall 11b of the housing body 11 by shrink fitting.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] As shown in FIGS. 3, 6 and the like, each tooth 43 has a tooth main body 46 and a tooth tip portion 44.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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. 6, both side surfaces in the circumferential direction of each tooth 43 form a slot partition surface 47a that defines the slot 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.

[0048] 4 to 6, 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 portions of the slot partition surface 47a of each tooth 43 other than the flange side surface 45a in the circumferential direction of the flange 45. 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 to each other 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 axis O direction. The bobbin 29 is made of a resin having electrical insulation and heat resistance, specifically, PPS (polyphenylene sulfide).

[0049] 1, 5 and 6, 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.

[0050] The resin molded portion 35 is made of a resin having electrical insulation and heat resistance, and specifically, is made of an epoxy resin mixed with a ceramic powder filler.

[0051] 1, 2, 5, and 6, the resin molded portion 35 covers the stator core 27 and the coils 31. The 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-shaped covering portion 59. The opening filling portions 58 and the ring-shaped covering portion 59 constitute the "tooth tip covering portions" of the present invention that mold the tooth tips 44.

[0052] 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-shaped covering portion 59 extends in an annular shape in the direction of the axis O and is molded to cover a portion of the tip inner peripheral surface 43a of each tooth tip portion 44. The outer peripheral surface 59a of the ring-shaped covering portion 59 faces the radially inner tip inner peripheral surface 43a of each tooth 43. Each coil end covering portion 55 is integrally formed with the ring-shaped covering portion 59, each opening filling portion 58, and each slot filling portion 57. The ring-shaped covering portion 59, each of the opening filling portions 58 and each of the slot filling portions 57 are integrally formed.

[0053] As shown in FIG. 5 and FIG. 6, a first gap 61 extending in the axial direction O is formed between the outer peripheral surface 59a of the ring-shaped covering portion 59 and the tip inner peripheral surface 43a of each tooth 43. The first gap 61 is an example of the "gap" in the present invention. Each first gap 61 extends over the entire tooth 43 in the axial direction O from the front end to the rear end of the stator core 27. Also, each first gap 61 is formed between the entire tip inner peripheral surface 43a of each tooth 43 and the outer peripheral surface 59a of the ring-shaped covering portion 59. That is, each first gap 61 extends over the entire circumferential direction of the tip inner peripheral surface 43a of each tooth 43. Each first gap 61 extends in an arc shape along the tip inner peripheral surface 43a.

[0054] The resin molded portion 35 can be molded by transfer molding after placing an integrated unit of the stator core 27, bobbin 29, and coil 31 in the cavity of a mold. More specifically, after attaching the bobbin 29 to the stator core 27, the coil 31 is wound around the teeth 43. This integrated unit of the stator core 27, bobbin 29, and coil 31 is placed in the cavity of the mold. Then, a resin material is injected into the cavity from one side in the direction of the axis O, and the resin molded portion 35 is molded by transfer molding.

[0055] The formation of the first void 61 is not particularly limited, but for example, the first void 61 can be formed by placing a wax part or a core made of wax in the portion of the cavity of the mold where the first void 61 is to be formed, molding the resin molded part 35, and then melting and expelling the wax part or removing the core.

[0056] When the resin material is injected in this transfer molding, a wax part or a core is disposed radially inward of the tip inner peripheral surface 43a of each tooth 43, and the outer peripheral surface of this wax part or core faces and abuts against the tip inner peripheral surface 43a of each tooth 43. This prevents the resin material from penetrating between the outer peripheral surface of the wax part or core and the tip inner peripheral 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 parts present in each minute gap between the electromagnetic steel sheets 37 are not formed integrally with the outer peripheral surface 59a of the ring-shaped covering portion 59.

[0057] 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.

[0058] 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.

[0059] 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, a ring-shaped covering portion 59 and an opening filling portion 58 serving as a tooth tip covering portion of the resin molded portion 35 mold the tooth tip portion 44. A first gap 61 is provided between the tooth tip portion 44 and the ring-shaped covering portion 59.

[0060] More specifically, a ring-shaped covering portion 59 that extends annularly in the axial direction O and faces the tip inner peripheral surface 43a of each tooth 43 is formed integrally with the coil end covering portion 55. A first gap 61 extending in the axial direction O is formed between the ring-shaped covering portion 59 and the entire tip inner peripheral surface 43a of each tooth 43. This prevents the minute resin portions interposed in the minute gaps between the electromagnetic steel sheets 37 from being integrally formed on the outer peripheral surface 59a of the ring-shaped covering portion 59. This prevents the anchor effect due to the uneven engagement between the electromagnetic steel sheets 37 and the outer peripheral surface 59a of the ring-shaped covering portion 59 between the tip inner peripheral surface 43a of each tooth 43 and the outer peripheral surface 59a of the ring-shaped covering portion 59. As a result, when the resin molded portion 35 thermally expands due to the heat from the coil 31, the extension of the ring-shaped covering portion 59 in the axial direction O is not restricted by the anchor effect.

[0061] As a result, stress concentration caused by thermal expansion of the resin at the boundary S (see FIG. 5) between the ring-shaped 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.

[0062] 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.

[0063] 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.

[0064] Furthermore, since the first gap 61 is present between the inner peripheral surfaces 43a of the tip portions of the teeth 43 and the ring-shaped covering portion 59, the effect of the difference in thermal expansion between the teeth 43 and the ring-shaped covering portion 59 is less likely to act from the teeth 43 to the ring-shaped covering portion 59. This also reduces the thermal stress acting on the ring-shaped covering portion 59.

[0065] Therefore, in the electric motor 3, and in turn in the electric compressor of the first embodiment including the electric motor 3, cracks or chips in the resin molded portion 35 of the stator 21 can be suppressed.

[0066] Example 2 The electric compressor of the second embodiment includes an electric motor 3A shown in Fig. 7 instead of the electric motor 3. The electric motor 3A is also an example of the "rotating electric machine" according to the present invention.

[0067] In this electric motor 3A, a second gap 63 is formed between the entire of both circumferential flange side surfaces 45a of each flange 45 of each tooth 43 and the opening filling portion 58. The second gap 63 is an example of a "gap" in the present invention. Each second gap 63 extends over the entire stator core 27 in the axial direction O. In addition, both circumferential ends of the first gap 61 are continuous with each second gap 63, and the first gap 61 and the pair of second gaps 63 are formed integrally.

[0068] In this electric motor 3A, a second gap 63 is also present 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 second 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 present 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.

[0069] 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.

[0070] Furthermore, since the second gap 63 is interposed between the flange side surface 45a of the flange 45 of the tooth 43 and the opening filling portion 58, the effect of the thermal expansion difference between the tooth 43 and the opening filling portion 58 is less likely to act from the tooth 43 to the opening filling portion 58. This also reduces the thermal stress acting on the opening filling portion 58.

[0071] The other configurations and effects are the same as those of the first embodiment.

[0072] Example 3 The electric compressor of the third embodiment includes an electric motor 3B shown in Fig. 8 instead of the electric motor 3. The electric motor 3B is also an example of the "rotating electric machine" of the present invention.

[0073] In this electric motor 3B, a pair of first gaps 61A extending in the axial direction O are formed between the outer peripheral surface 59a of the ring-shaped covering portion 59 and the tip inner peripheral surface 43a of each tooth 43. The first gaps 61A are an example of the "gap" in the present invention. Each of the first gaps 61A extends over the entire teeth 43 in the axial direction O, from the front end to the rear end of the stator core 27. Each of the first gaps 61A is formed partially on the tip inner peripheral surface 43a of each tooth 43. That is, each of the first gaps 61A is formed at both circumferential ends of the tip inner peripheral surface 43a of the teeth 43.

[0074] In the electric motor 3B, second gaps 63 are formed between the entirety of both circumferential flange side surfaces 45a of each flange 45 of each tooth 43 and the opening filling portion 58. Each second gap 63 extends over the entirety of the stator core 27 in the direction of the axis O. Also, one circumferential end of each first gap 61A is continuous with the second gap 63, and the first gap 61A and the second gap 63 are formed integrally.

[0075] Furthermore, in this electric motor 3B, the first gap 61A is partially formed, so that the inner circumferential surfaces 43a of the tips of the teeth 43 and the outer circumferential surface 59a of the ring-shaped covering portion 59 are in partial contact with each other. This allows the heat generated in the coil 31 to be conducted to each tooth 43 via the coil end covering portion 55 and the ring-shaped covering portion 59, which can contribute to improving the heat dissipation efficiency of the electric motor 3B.

[0076] The other configurations are the same as those of the second embodiment, and this electric motor 3B basically achieves the same effects as the electric motor 3A of the second embodiment.

[0077] Example 4 The electric compressor of the fourth embodiment includes an electric motor 3C shown in Fig. 9 in place of the electric motor 3. The electric motor 3C is also an example of the "rotating electric machine" of the present invention.

[0078] In this electric motor 3C, a second gap 63 is formed between the entirety of both circumferential flange side surfaces 45a of each flange 45 of each tooth 43 and the opening filling portion 58. Each second gap 63 extends entirely in the axial direction O of the stator core 27. Note that in this electric motor 3C, a first gap 61 is not formed.

[0079] In this electric motor 3C, a second 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, an anchor effect due to the uneven engagement between the electromagnetic steel sheet 37 and the minute resin portion 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.

[0080] 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.

[0081] Furthermore, in this electric motor 3C, the first gap 61 is not formed, so the entire inner circumferential surfaces 43a of the tips of the teeth 43 are in contact with the outer circumferential surface 59a of the ring-shaped covering portion 59. This allows heat generated in the coil 31 to be conducted to each tooth 43 via the coil end covering portion 55 and the ring-shaped covering portion 59, which can contribute to improving the heat dissipation efficiency of the electric motor 3C.

[0082] The other configurations are the same as those of the embodiment 1. Therefore, this electric motor 3C also basically achieves the same effects as the electric motor 3 of the embodiment 1, except that the effects due to the first gap 61 are not achieved.

[0083] In the above, the present invention has been described based on Examples 1 to 4. However, the present invention is not limited to the above Examples 1 to 4, 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.

[0084] For example, in the electric motor 3 of the first embodiment, the first gap 61 may be formed partially with respect to the inner circumferential surface 43a of the tip end portion of the tooth 43.

[0085] Furthermore, in the electric motor 3A of the second embodiment, the first gap 61 may be formed partially relative to the tip inner surface 43a of the tooth 43, and similarly, the second gap 63 may be formed partially relative to the flange side surface 45a of the flange portion 45.

[0086] Similarly, in the electric motor 3B of the third embodiment and the electric motor 3C of the fourth embodiment, the second gap 63 may be formed partially relative to the flange side surface 45a of the flange 45.

[0087] In addition, in the first to fourth 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.

[0088] 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.

[0089] 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. [Industrial Applicability]

[0090] The present invention can be used in electrically-driven devices such as vehicle electric compressors. [Explanation of symbols]

[0091] 1. Housing 3, 3A, 3B, 3C...Electric motor (rotating electric machine) 21...Stator 23...Rotation axis 25…Rotor 27…Stator core 29...Bobbin (insulating material) 31…Coil 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 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-shaped covering part (teeth tip covering part) 61, 61A...1st void (void) 63…Second void (void)

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 rotating electric machine comprising: a gap extending in the stacking direction between the tooth tip portions and the tooth tip covering portions.

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; 2 . The rotating electric machine according to claim 1 , wherein the gap is provided at least one of between the inner peripheral surface of the tip portion and the tooth tip covering portion and between the side surface of the tip portion and the tooth tip covering portion.

3. 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; 3. The rotating electric machine according to claim 2, 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 therebetween to the outer peripheral surface of the tip portion of the other of the pair of teeth.

4. 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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