Rotary electric machine

Abstract

To at least partially prevent upsizing of a rotary electric machine due to a seal structure of a coolant passage, while forming the coolant passage provided in a stator in such a manner that a coolant does not leak to a rotor side.SOLUTION: A rotary electric machine comprises: a stator core which has a plurality of tooth parts, and in which a stator inner peripheral surface is closed; a coil wire which is wound around the stator core in such a manner that it is inserted into a slot, and which forms a coil end part on an axially outer side with respect to an axial end surface of the stator core; a cover member which covers the coil end part from the axially outer side, a radially inner side, and a radially outer side; and a coolant passage between the cover member and the axial end surface of the stator core. The cover member has a first axial end which comes into contact with the axial end surface of the stator core around a central axis of the stator core, on the radially inner side than the coil wire in the slot. The first axial end forms a seal part for the coolant passage, between itself and the axial end surface of the stator core.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A technique is known in which the refrigerant flow path provided in the stator is made into a closed space so that the refrigerant does not leak to the rotor side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-193572 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-described conventional technology, it is difficult to efficiently form a seal structure to prevent refrigerant leakage to the rotor side. For example, forming a seal axially outward of the stator results in an increase in the axial size of the rotating electrical machine.

[0005] Therefore, in one aspect, the present disclosure aims to form a refrigerant flow path provided in a stator so that the refrigerant does not leak to the rotor side, while at least partially preventing an increase in size of a rotating electric machine due to the sealing structure of the refrigerant flow path. [Means for solving the problem]

[0006] According to one aspect, a stator core has a plurality of teeth and an inner peripheral surface of the stator is closed; a coil wire wound around the stator core in a manner to be inserted into slots formed between the plurality of teeth in the circumferential direction, the coil wire forming a coil end portion on the axial outer side relative to an axial end face of the stator core; a cover member that covers the coil end portion from an axially outer side, a radially inner side, and a radially outer side; a refrigerant flow path between the cover member and an axial end surface of the stator core, the cover member has a first axial end portion that is radially inward of the coil wire in the slot and abuts against an axial end surface of the stator core around a central axis of the stator core, The first axial end portion forms a seal portion for the refrigerant flow path between itself and an axial end face of the stator core. [Effects of the Invention]

[0007] In one aspect, according to the present disclosure, it is possible to form a refrigerant flow path provided in a stator so as to prevent refrigerant from leaking to the rotor side, while at least partially preventing an increase in size of a rotating electric machine due to the sealing structure of the refrigerant flow path. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically showing a cross-sectional structure of a motor according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a portion of a stator core. [Figure 3] FIG. 2 is a cross-sectional view of the stator taken along line AA in FIG. 1. [Figure 3A] FIG. 4 is an enlarged view of a portion Q3 in FIG. [Figure 4] FIG. 2 is an enlarged view of part Q4 in FIG. [Figure 5] FIG. 2 is an enlarged view of part Q5 in FIG. [Figure 6] FIG. 4 is a perspective view of the cover member as viewed from the outside in the axial direction. [Figure 7] FIG. 4 is a perspective view of the cover member as viewed from the axially inner side. [Figure 8] 4 is a cross-sectional view of a portion of the cover member taken along a plane passing through the rotation axis. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Furthermore, shapes and the like in the drawings may be partially exaggerated for the sake of explanation. Furthermore, in the drawings, for ease of viewing, reference symbols may be assigned only to some of the parts that exist with the same attribute.

[0010] Fig. 1 is a cross-sectional view schematically showing the cross-sectional structure of a motor 1 according to an embodiment. Fig. 2 is a cross-sectional view of a portion of a stator core 211. Fig. 3 is a cross-sectional view of a stator 21 taken along line AA in Fig. 1. Fig. 3A is an enlarged view of a portion Q3 in Fig. 3.

[0011] 1 shows the rotating shaft 12 of the motor 1. In the following description, the axial direction refers to the direction in which the rotating shaft (center of rotation) 12 of the motor 1 extends, the axially outer side refers to the side away from the axial center of the stator core 211, and the axially inner side refers to the side toward the axial center of the stator core 211. The radial direction refers to the radial direction centered on the rotating shaft 12, the radially outer side refers to the side away from the rotating shaft 12, and the radially inner side refers to the side toward the rotating shaft 12. The circumferential direction corresponds to the direction of rotation around the rotating shaft 12.

[0012] The motor 1 may be a motor for driving a vehicle, such as that used in a hybrid vehicle or an electric vehicle, but the motor 1 may also be used for any other purpose.

[0013] The motor 1 is housed in and supported by a motor case 10. The motor case 10 may also house a driving element (such as a reduction mechanism) other than the motor 1. The motor case 10 may be formed by combining multiple case members.

[0014] In this embodiment, the motor 1 is an inner rotor type, and the stator 21 is provided so as to surround the outside of the rotor 30 in the radial direction.

[0015] The stator 21 is fixed to the motor case 10 by bolts BT1. The stator 21 includes a stator core 211, coil wires 22, wedge members 24 (see FIG. 3A), and a cover member .

[0016] Stator core 211 is formed, for example, from laminated steel plates of a circular magnetic material, but may also be formed from a green compact obtained by compressing and solidifying magnetic powder. Stator core 211 may have an inner peripheral portion and an outer peripheral portion (e.g., a back yoke portion) formed as separate pieces. Stator core 211 may also be formed by combining split cores that are divided in the circumferential direction.

[0017] As shown in FIG. 2 , the stator core 211 has teeth 214 on the radially inner side at a constant pitch along the circumferential direction. Slots 216 are formed between adjacent teeth 214 in the circumferential direction. Each slot 216 opens on both axial sides and also opens radially inward. As shown in FIGS. 3 and 3A , the radially inner opening of each slot 216 is blocked by a wedge member 24. The wedge member 24 may extend over the entire axial direction of the stator core 211 without extending radially inward beyond the teeth 214. In this embodiment, the teeth 214 have a shape in which the circumferential dimension increases at the radially inner end 2140. That is, the teeth 214 have a shape in which the radially inner end 2140 expands in the circumferential direction.

[0018] The coil wire 22 may be a conductor wire covered with an insulating coating. The cross section of the coil wire 22 may be any shape, such as rectangular (rectangular wire) or circular (round wire). The coil wire 22 is wound around the stator core 211 to form a stator coil. The coil wire 22 may be wound in any way, such as concentrated winding or distributed winding.

[0019] The coil wire 22 is wound around the stator core 211 while being inserted into the slots 216. Then, a coil end portion 223 is formed axially outward from the axial end face of the stator core 211. The coil end portion 223 is formed by a portion of the coil wire 22 that spans between the slots 216 in the circumferential direction (a portion outside the slots 216). The coil end portion 223 is formed on each axial side of the stator core 211. The coil end portion 223 has an annular shape when viewed in the axial direction.

[0020] The cover member 26 surrounds the coil end portion 223. That is, the cover member 26 covers the axially outer side, the radially inner side, and the radially outer side of the coil end portion 223. The cover member 26 may be made of an insulating material such as a resin material, or may be made of a metal material with relatively high heat dissipation properties.

[0021] An oil passage 80 (see FIG. 1) having an annular shape when viewed in the axial direction is formed between the cover member 26 and the axial end face of the stator core 211. Further details of the cover member 26 will be described later.

[0022] The rotor 30 is disposed radially inside the stator 21 .

[0023] The rotor 30 includes a rotor core 32 and a rotor shaft 34 .

[0024] The rotor core 32 is fixed to the radially outer surface of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has an axial hole 320 into which the rotor shaft 34 is fitted. The rotor core 32 may be fixed to the rotor shaft 34 by shrink fitting, press fitting, or the like. For example, the rotor core 32 may be connected to the rotor shaft 34 by key connection or spline connection. The rotor shaft 34 is rotatably supported in the motor case 10 via bearings (bearing 14a, etc.). The rotor shaft 34 defines the rotary axis 12 of the motor 1.

[0025] The rotor core 32 is formed of, for example, laminated steel plates of a circular magnetic material. The rotor core 32 may have permanent magnets provided on the inside or on the radially outer surface thereof.

[0026] 1 shows the motor 1 having a specific structure, but the structure of the motor 1 is not limited to such a specific structure. For example, although the rotor shaft 34 is solid in FIG. 1, it may be hollow.

[0027] Next, the characteristic configuration of this embodiment will be described with reference to Figures 1, 3, and 3A, as well as Figure 4 onwards. The following mainly describes the cover member 26 on one axial side and the configuration related thereto, but the configuration on the other axial side may be similar.

[0028] Fig. 4 is an enlarged view of part Q4 in Fig. 1. Fig. 5 is an enlarged view of part Q5 in Fig. 1. Fig. 6 is a perspective view of the cover member 26 as viewed from the outside in the axial direction, and Fig. 7 is a perspective view of the cover member 26 as viewed from the inside in the axial direction. Fig. 8 is a cross-sectional view of a portion of the cover member 26 taken along a plane passing through the rotation shaft 12.

[0029] As shown in FIGS. 6 and 7 , the cover member 26 has an annular shape when viewed in the axial direction. The cover member 26 has an axially outer top surface portion 2630, a radially outer circumferential surface portion 2631, and a radially inner circumferential surface portion 2632 that form a C-shape when viewed in cross section along a plane passing through the rotating shaft 12 (see FIG. 1 and FIG. 8 described later). The top surface portion 2630 and the circumferential surface portions 2631 and 2632 of the cover member 26 may have substantially the same C-shape when viewed in cross section along a plane passing through the rotating shaft 12 (see FIGS. 1 and 8 ) at each circumferential position of the circumferential section. However, the cover member 26 may have an oil inlet and an oil outlet on the circumferential surface portion 2631 or the like, although not shown. The cover member 26 forms an oil passage 80 with a C-shaped space formed by the top surface portion 2630 and the circumferential surface portions 2631 and 2632.

[0030] The radially outer peripheral surface portion 2631 faces the radially outer side of the coil end portion 223 from the radially outer side over the entire circumference. An axially inner end portion 26312 of the radially outer peripheral surface portion 2631 abuts against the stator core 211 and is fastened to the stator core 211 with a bolt BT1. The radially outer peripheral surface portion 2631 abuts against the stator core 211 radially outer than the slots 216 (radially outer than the coil end portion 223). That is, the radially outer peripheral surface portion 2631 axially abuts against the end surface of the yoke, which is one of the axial end surfaces of the stator core 211.

[0031] The radially outer peripheral surface portion 2631 may have a uniform cross-sectional shape as shown in Fig. 8 over the entire circumference, except for a flange portion 26310 described later. In this case, the radially outer peripheral surface portion 2631 abuts against the stator core 211 over the entire circumference. In this way, the radially outer peripheral surface portion 2631 abuts against the stator core 211 over the entire circumference, thereby forming a radially outer seal portion 91 for the oil passage 80.

[0032] In this embodiment, the radially outer circumferential surface portion 2631 abuts against the stator core 211 via a seal layer 71 (see FIG. 5 ). Specifically, an axially inner end portion 26312 of the radially outer circumferential surface portion 2631 abuts against the axial end surface of the stator core 211 via the seal layer 71. The seal layer 71 is formed of a material (hereinafter also referred to as a "sealing material") that is softer or more elastic than the materials of the stator core 211 and the cover member 26. The seal layer 71 functions to prevent oil in the oil passage 80 from leaking outward in the radial direction from between the radially outer circumferential surface portion 2631 and the stator core 211. This configuration can efficiently improve the sealing performance between the radially outer circumferential surface portion 2631 and the stator core 211.

[0033] The sealing layer 71 may be provided as part of the radially outer peripheral surface portion 2631 by applying a sealing material before assembling the cover member 26 to the stator core 211. Alternatively, the sealing layer 71 may be formed integrally with the radially outer peripheral surface portion 2631. Alternatively, the sealing layer 71 may be provided by applying a sealing material to the end face of the stator core 211 before assembling the cover member 26 to the stator core 211. Alternatively, the sealing layer 71 may be formed by a ring-shaped member made of a sealing material.

[0034] Additionally, the radially outer peripheral surface portion 2631 has flange portions 26310 protruding radially outward at a plurality of locations in the circumferential direction. The flange portions 26310 function as fixing portions through which bolts BT1 for fastening the cover member 26 to the stator core 211 pass. The number of flange portions 26310 is arbitrary and may be two, three, or more. In this embodiment, three flange portions 26310 are provided at equal intervals of 120 degrees.

[0035] In this case, the above-described sealing layer 71 may also be provided on the flange portion 26310. That is, the sealing layer 71 may also be provided between the flange portion 26310 and the stator core 211. According to this configuration, the sealing performance between the radially outer peripheral surface portion 2631 and the stator core 211 can be efficiently improved.

[0036] The radially inner circumferential surface portion 2632 faces the radially inner side of the coil end portion 223 from the radially inner side over the entire circumference. An axially inner end face of the radially inner circumferential surface portion 2632 abuts on the axial end face of the stator core 211, except for the circumferential section of the slot 216. The radially inner circumferential surface portion 2632 abuts on the stator core 211 radially outer than the radially inner end faces of the tooth portions 214. The radially inner circumferential surface portion 2632 preferably abuts on the stator core 211 at approximately the same radial position as the radial position at which the wedge member 24 is disposed. That is, in the circumferential section of the slot 216, an axially inner end face of the radially inner circumferential surface portion 2632 abuts on the axial end face of the wedge member 24. For this purpose, the axial end face of the wedge member 24 may extend in approximately the same plane as the axial end face of the stator core 211. In Figures 3 and 3A, the contact area of ​​the radially inner peripheral surface portion 2632 of the stator core 211 is shown by the hatched area surrounded by a dotted line.

[0037] 3, the radially inner peripheral surface portion 2632 preferably abuts against the stator core 211 radially inner than the coil wire 22 in the slot 216. In this case, an oil passage 80 that encompasses the entire coil end portion 223 can be formed.

[0038] 8 . In this case, the radially inner peripheral surface portion 2632 abuts against the stator core 211 over the entire circumference except for the circumferential section of the slot 216, and abuts against the wedge member 24 in the circumferential section of the slot 216. In this way, the radially inner peripheral surface portion 2632 abuts against either the stator core 211 or the wedge member 24 over the entire circumference, thereby forming a radially inner seal portion 92 for the oil passage 80.

[0039] In this embodiment, the radially inner circumferential surface portion 2632 abuts against the stator core 211 via the seal layer 72. Specifically, the axially inner end portion 26322 of the radially inner circumferential surface portion 2632 abuts against the axial end surface of the stator core 211 or the axial end surface of the wedge member 24 via the seal layer 72. Similar to the seal layer 71 described above, the seal layer 72 is formed of a material that is softer or more elastic than the material of the stator core 211 or the cover member 26. The seal layer 72 functions to prevent oil in the oil passage 80 from leaking radially inward from between the radially inner circumferential surface portion 2632 and the stator core 211. This configuration can efficiently improve the sealing performance between the radially inner circumferential surface portion 2632 and the stator core 211.

[0040] Note that the sealing layer 72 may be provided as part of the radially inner peripheral surface portion 2632 by applying a sealing material before assembling the cover member 26 to the stator core 211, or may be formed integrally with the radially inner peripheral surface portion 2632. Alternatively, the sealing layer 71 may be provided by applying a sealing material to the end face of the stator core 211 before assembling the cover member 26 to the stator core 211. Furthermore, the sealing layer 72 may be formed of a ring-shaped member made of a sealing material.

[0041] In the present embodiment, as described above, the cover member 26 is fixed to the stator core 211 by the flange portion 26310 of the radially outer circumferential surface portion 2631, and the radially inner circumferential surface portion 2632 is not directly fixed to the stator core 211. In this configuration, the degree of contact (and therefore the sealing performance) between the radially outer circumferential surface portion 2631 and the stator core 211 tends to be higher than the degree of contact between the radially inner circumferential surface portion 2632 and the stator core 211. If the degree of contact between the radially inner circumferential surface portion 2632 and the stator core 211 is relatively low, oil leakage from between the radially inner circumferential surface portion 2632 and the stator core 211 may occur.

[0042] Therefore, in this embodiment, when the cover member 26 is in a normal position in a standalone state (before being assembled to the stator core 211), the radially inner circumferential surface portion 2632 extends more axially inward than the radially outer circumferential surface portion 2631. That is, as shown in Fig. 8, the axial dimension L2 of the radially inner circumferential surface portion 2632 is greater than the axial dimension L1 of the radially outer circumferential surface portion 2631. Note that the axial dimensions L1 and L2 referred to here are dimensions from a plane (e.g., the top surface portion 2630) perpendicular to the axial direction.

[0043] According to this dimensional relationship, when cover member 26 is assembled to stator core 211, a fastening force presses radially outer circumferential surface portion 2631 toward the axial end face of stator core 211, and also presses radially inner circumferential surface portion 2632 toward the axial end face of stator core 211. That is, by fixing radially outer circumferential surface portion 2631 to stator core 211, due to the above-described dimensional relationship, radially inner circumferential surface portion 2632 is pressed against stator core 211. As a result, even in a configuration in which radially inner circumferential surface portion 2632 is not directly fixed to stator core 211 as described above, it is possible to improve the sealing performance between radially inner circumferential surface portion 2632 and stator core 211.

[0044] Furthermore, by improving the sealing performance between the radially inner peripheral surface portion 2632 and the stator core 211, it is possible to effectively increase the possibility of reducing leakage of oil in the oil passage 80 in the radially inner direction. Oil leaking in the radially inner direction from the oil passage 80 may reach the gap between the rotor 30 and the stator 21 in the radial direction, causing loss (i.e., drag loss) during rotation of the rotor 30. According to this embodiment, it is possible to effectively reduce the possibility of such loss occurring.

[0045] As described above, according to the present embodiment, the radially outer peripheral surface portion 2631 and the radially inner peripheral surface portion 2632 of the cover member 26 axially abut against the axial end surfaces of the stator core 211, thereby forming seal portions 91 and 92 for the oil passage 80. In this case, the seal portions 91 and 92 can be formed within the radial range of the stator core 211. Furthermore, in this case, the seal portions 91 and 92 are located axially inward of the axial end portions of the stator 21 (i.e., the axial end surfaces of the coil end portions 223). Therefore, according to the present embodiment, the seal portions 91 and 92 can be formed without increasing the size of the stator 21 (and therefore the size of the rotating shaft 12). In other words, according to the present embodiment, the oil passage 80 provided in the stator 21 can be formed so as to prevent refrigerant from leaking to the rotor 30, while at the same time at least partially preventing the motor 1 from becoming larger due to the seal portions for the oil passage 80.

[0046] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0047] For example, cover member 26 is fixed to stator core 211, but instead of or in addition to this, cover member 26 may be fixed to motor case 10. For example, cover member 26 may be fixed to motor case 10 via a flange portion such as flange portion 26310 with bolts (not shown).

[0048] In the above-described embodiment, the cover member 26 is provided for the coil wire 22 of the stator 21, but this is not limiting. For example, in the case of a wound field motor in which the coil wire is provided on the rotor core, a cover member similar to the cover member 26 may be provided for the rotor core.

[0049] In the above-described embodiment, the wedge member 24 functions as a sealing member that closes the radial opening of the slot 216, but the sealing member may be realized in other ways. For example, a similar sealing function may be realized by a resin material that can be filled into the slot 216 or a foamed material of a foam slot paper. [Explanation of symbols]

[0050] 1 motor (rotating electric machine), 211 stator core, 214 teeth portion, 216 slot, 22 coil wire, 223 coil end portion, 24 wedge member (one example of a sealing member), 26 cover member, 80 oil passage (refrigerant passage), 2631 radially outer peripheral surface portion, 26312 axially inner end portion (second end portion), 2632 radially inner peripheral surface portion, 26322 axially inner end portion (first end portion), 71 seal layer (second portion), 72 seal layer (first portion), 91 seal portion (second seal portion), 92 seal portion (first seal portion), BT1 bolt

Claims

1. a stator core having a plurality of teeth and a closed inner peripheral surface; a coil wire wound around the stator core in a manner to be inserted into slots formed between the plurality of teeth in the circumferential direction, the coil wire forming a coil end portion on the axially outer side relative to an axial end face of the stator core; a cover member that covers the coil end portion from an axially outer side, a radially inner side, and a radially outer side; a refrigerant flow path between the cover member and an axial end surface of the stator core, the cover member has a first axial end portion that is radially inward of the coil wire in the slot and abuts against an axial end surface of the stator core around the central axis of the stator core, The first axial end portion forms a seal portion for the refrigerant flow path between itself and an axial end face of the stator core.

2. The rotating electric machine according to claim 1 , wherein the seal portion includes a first portion formed of a material that is softer or has higher elasticity than both a material of the stator core and a material of the cover member.

3. The rotating electric machine according to claim 1 , wherein the first axial end portion is pressed toward an axial end face of the stator core.

4. the cover member has a second axial end portion that is radially outward of the coil wire in the slot and abuts against an axial end surface of the stator core around the central axis of the stator core, the second axial end portion has a fixing portion for fastening the cover member to the stator core, 4. The rotating electric machine according to claim 3, wherein when the cover member is fastened to the stator core via the fixing portion, the second axial end portion forms a second sealing portion for the refrigerant flow path between the second axial end portion and the axial end face of the stator core, and the first axial end portion is pressed toward the axial end face of the stator core.

5. The rotating electric machine according to claim 4 , wherein the second seal portion includes a second portion formed of a material that is softer or has higher elasticity than both the material of the stator core and the material of the cover member.

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