Rotating electric machine and manufacturing method of rotating electric machine

Abstract

A rotor core (2) having a plurality of magnet insertion holes (29a, 29b) is provided with a hole part (8) between a fixing hole (23a) and outermost peripheral edge parts (29a1, 29b1) of the magnet insertion holes (29a, 29b). The hole part (8) is composed of a positioning function part (8a) and a lightweight function part (8b).

Description

Rotating electric machine and manufacturing method thereof

[0001] The present disclosure relates to a rotating electric machine and a method for manufacturing a rotating electric machine.

[0002] A rotating electric machine has been known that includes a stator having an annular stator core and a stator coil attached to the stator core, a rotor having a rotor core inserted into an inner space of the stator core, and a plurality of permanent magnets embedded in the rotor core to form field poles. In a rotating electric machine configured in this manner, the stator core typically has a plurality of teeth that protrude radially inward and are arranged at regular intervals in the circumferential direction, and the rotor core has a plurality of magnet insertion holes near its outer circumferential surface for inserting the permanent magnets that form field poles, and bridge portions that define the magnet holes.

[0003] Conventionally, in a rotating electric machine configured as described above, a rotating electric machine has been disclosed in which a hole is formed in the rotor core into which a jig can be inserted to position the rotor core relative to the stator core when the rotor core is processed or assembled (see, for example, Patent Document 1).

[0004] Also disclosed is a rotating electric machine in which polygonal gap holes are formed in the rotor core as flux barriers to regulate the flow of magnetic flux (see, for example, Patent Document 2).Furthermore, a rotating electric machine in which a cavity is formed in the rotor core through which a coolant flows has been disclosed (see, for example, Patent Document 3).The gaps in the rotor core disclosed in Patent Document 2 and the cavity in the rotor core disclosed in Patent Document 3 also serve the function of reducing the weight of the rotor.

[0005] JP 2000-4550 A JP 2019-165592 A JP 2005-184957 A

[0006] The conventional rotating electric machine described above has, as rotor components, a rotor core made of many laminated electromagnetic steel plates, a plurality of permanent magnets inserted into a plurality of magnet insertion holes formed in the rotor core, and a rotor shaft whose axial length is longer than that of the rotor core, and the rotor shaft is rotatably supported by bearings. However, since the rotor is configured as described above, it is heavy, which increases mechanical loss in the bearings that support the rotor shaft, and reduces the efficiency of the rotating electric machine. Furthermore, the heavier the rotor, the worse the efficiency of the rotating electric machine becomes.

[0007] Forming holes in the rotor core is an effective way to reduce the weight of the rotor core. However, depending on the location of the holes in the rotor core, the holes may obstruct the flow of magnetic flux within the rotor core, increasing iron loss, or the rotor may lack strength against stress due to centrifugal force or stress caused by the fitting of the rotor shaft and rotor core. Therefore, the area in which holes can be formed is limited.

[0008] The conventional rotating electric machine disclosed in Patent Document 1 has positioning holes in the rotor core, but if holes for reducing the rotor weight are provided in addition to the positioning holes, both holes must be provided in a limited area of ​​the rotor core to prevent an increase in iron loss and a decrease in strength of the rotor. However, if the weight-reducing holes and the positioning holes are formed separately in the limited area, a bridge portion is formed that separates the two holes, and stress concentrates in the bridge portion, causing a decrease in the strength of the rotor core.

[0009] Furthermore, the conventional rotating electric machine disclosed in Patent Document 2 has polygonal void holes as flux barriers, and the conventional rotating electric machine disclosed in Patent Document 3 has a cavity through which a refrigerant flows, but neither has holes for positioning the rotor core, and furthermore, the void holes and cavity portions are not provided in areas of the rotor core that take into consideration preventing an increase in iron loss and a decrease in strength of the rotor.

[0010] The present disclosure discloses technology for solving the above-mentioned problems, and aims to provide a rotating electric machine that enables cost reduction during manufacturing and improvement of the efficiency of the rotating electric machine.

[0011] Another object of the present disclosure is to provide a method for manufacturing a rotating electric machine that can reduce costs during manufacturing of the rotating electric machine and improve the efficiency of the rotating electric machine.

[0012] The rotating electric machine disclosed herein is a rotating electric machine comprising: a stator core formed in an annular shape; a stator coil attached to the stator core; a rotor core whose outer peripheral surface faces the inner peripheral surface of the stator core via a gap and has a plurality of magnet insertion holes; a plurality of permanent magnets inserted into the plurality of magnet insertion holes and forming a plurality of field poles in the rotor core; a rotor shaft that passes through a fixing hole provided in the radial center of the rotor core and supports the rotor core; and a bearing that rotatably supports the rotor shaft, wherein the rotor core has a hole portion formed between the fixing hole and the outermost peripheral edge of the magnet insertion hole, and the hole portion is composed of a positioning function portion that contributes to positioning the rotor core, and a weight reduction function portion that contributes to reducing the weight of the rotor core.

[0013] Furthermore, the manufacturing method of the rotating electric machine disclosed herein is a manufacturing method of a rotating electric machine for manufacturing the above-mentioned rotating electric machine, and is characterized by comprising: a stator core holding process for holding the stator core by a stator core holding portion of an axial alignment jig; a rotor core positioning process for inserting a plurality of rod-shaped positioning members in a rotor core positioning portion of the axial alignment jig into the positioning function portion in the hole portion of the rotor core to position the rotor core relative to the stator core; and an assembly process for assembling at least a portion of the rotating electric machine in a state in which the rotor core has been positioned relative to the stator core by the rotor core positioning process.

[0014] Furthermore, the manufacturing method of a rotating electric machine disclosed herein is a manufacturing method of a rotating electric machine that manufactures a rotating electric machine that includes an end plate that abuts the rotor core in the axial direction at at least one axial end of the rotor core, the end plate having a hole having a positioning function portion that matches at least a positioning function portion in a hole formed in the rotor core, and is characterized by comprising: a stator core holding process that holds the stator core with a stator core holding portion of an axial alignment jig; a rotor core positioning process that inserts a plurality of rod-shaped positioning members in the rotor core positioning portion of the axial alignment jig into the positioning function portions in the hole formed in the end plate and the positioning function portions in the hole formed in the rotor core, to position the rotor core relative to the stator core; and an assembly process that assembles at least a portion of the rotating electric machine in a state where the rotor core has been positioned relative to the stator core by the rotor core positioning process.

[0015] Furthermore, the manufacturing method for a rotating electric machine disclosed herein is a manufacturing method for a rotating electric machine that manufactures a rotating electric machine that includes an end plate that abuts axially against the rotor core at at least one axial end of the rotor core, the end plate having a hole having a positioning function portion that matches at least a positioning function portion in a hole formed in the rotor core, and is characterized in that positioning between the end plate and the rotor core is performed by inserting a plurality of rod-shaped positioning portions provided on a jig into both the positioning function portion in the hole provided in the end plate and the positioning function portion in the hole provided in the rotor core.

[0016] Furthermore, the manufacturing method of the rotating electric machine disclosed herein is a manufacturing method of a rotating electric machine that manufactures a rotating electric machine that includes an end plate that abuts axially against the rotor core at at least one axial end of the rotor core, the end plate having a plurality of rod-shaped positioning members extending in the axial direction of the rotor core, and the plurality of positioning members being inserted into at least the positioning function portions in the plurality of hole portions formed in the rotor core, and is characterized in that positioning between the end plate and the rotor core is performed by inserting the plurality of rod-shaped positioning members provided on the end plate into the positioning function portions in the hole portions provided in the rotor core.

[0017] According to the rotating electric machine of the present disclosure, it is possible to obtain a rotating electric machine that can reduce costs during manufacturing and improve the efficiency of the rotating electric machine.

[0018] Furthermore, according to the method for manufacturing a rotating electric machine according to the present disclosure, it is possible to obtain a rotating electric machine that allows for reduced costs during manufacturing and improved efficiency of the rotating electric machine.

[0019] Fig. 1 is a longitudinal sectional view that schematically shows a rotating electric machine according to embodiment 1. Fig. 2 is a sectional view of a rotor of the rotating electric machine according to embodiment 1. Fig. 3 is an explanatory diagram of a rotor of the rotating electric machine according to embodiment 1. Fig. 4 is an explanatory diagram of a rotor of a rotating electric machine according to embodiment 2. Fig. 5 is an explanatory diagram of a rotor of a rotating electric machine according to embodiment 3. Fig. 6 is an explanatory diagram of a rotor of a rotating electric machine according to embodiment 4. Fig. 7 is an explanatory diagram of a rotor of a rotating electric machine according to embodiment 5. Fig. 8 is an explanatory diagram of a rotor of a rotating electric machine according to embodiment 6. Fig. 9 is an explanatory diagram of a rotor of a rotating electric machine according to embodiment 7.

[0020] The rotating electric machine according to each embodiment of the present disclosure described below is a permanent magnet synchronous motor. Embodiment 1. Fig. 1 is a longitudinal cross-sectional view that schematically shows a rotating electric machine according to embodiment 1. In Fig. 1, the rotating electric machine 100 includes a stator 1 and a rotor 2. The stator 1 includes a cylindrical metal frame 12, an annular stator core 13 fitted to the inner peripheral surface of the frame 12, and a stator coil 14 attached to the stator core 13. The stator coil 14 is configured, for example, by a Y-connected three-phase coil.

[0021] The frame 12 has a flange 12a at one axial end thereof for fixing the rotating electric machine 100 to, for example, another vehicle component (not shown). The stator core 13 is made of a large number of annular electromagnetic steel plates stacked in the axial direction, and has a plurality of teeth (not shown) protruding from its inner circumferential surface and a plurality of slots (not shown) formed between adjacent teeth. Stator coils 14 are inserted into the slots.

[0022] The rotor 2 includes a rotor core 23 inserted into the internal space of the stator core 13, with its outer peripheral surface facing the inner peripheral surface of the stator core 13 across a gap, a plurality of permanent magnets 24 embedded near the outer peripheral surface of the rotor core 23, a first end plate 25a abutting one axial end of the rotor core 23, a second end plate 25b abutting the other axial end of the rotor core 23, and a rotor shaft 26 passing through a fixing hole 23a provided in the radial center of the rotor core 23 and the first and second end plates 25a and 25b. The rotor core 23 is made of a number of annular electromagnetic steel plates stacked in the axial direction.

[0023] Both axial ends of rotor shaft 26 are rotatably supported by a first bearing 27a and a second bearing 27b, which are respectively provided on a pair of brackets (not shown) fixed to frame 12. The axial position of rotor core 23 relative to rotor shaft 26 is regulated by second end plate 25b abutting against a stopper 28 provided on rotor shaft 26.

[0024] The rotor core 23 is provided with eight first magnet insertion holes 29a and eight second magnet insertion holes 29b facing the first magnet insertion holes 29a. The aforementioned permanent magnets 24 are inserted into the first magnet insertion holes 29a and the second magnet insertion holes 29b. Each permanent magnet 24 extends from one axial end to the other axial end of the rotor core 23 and is divided into a plurality of magnets, for example, six magnets, in the axial direction of the rotor core 23.

[0025] The first end plate 25a and the second end plate 25b abut against one axial end and the other axial end of the rotor core 23, respectively, to prevent the permanent magnets 24 from falling out of or protruding from the first magnet insertion holes 29a and the second magnet insertion holes 29b. Note that holes or plates serving as balance weights for adjusting the rotational balance of the rotor 2 may be added to at least one of the first end plate 25a and the second end plate 25b.

[0026] Next, the configuration of rotor core 23 will be described. Figure 2 is a cross-sectional view of the rotor of the rotating electric machine according to embodiment 1, showing the cross section of the rotor taken along line A-A in Figure 1 as viewed from the direction of the arrow. In Figure 2, rotor core 23 is supported by rotor shaft 26 inserted into fixing hole 23a provided in the center of rotor core 23.

[0027] The rotor shaft 26 integrally fixes the rotor core 23, the first end plate 25a (see FIG. 1), and the second end plate 25b (see FIG. 2), and transmits the rotational force of the rotor core 23 to the outside of the rotating electric machine 100. In the first embodiment, the rotor shaft 26 is configured as a solid shaft. In the first embodiment, the rotor core 23, the first end plate 25a, and the second end plate 25b are fitted to the rotor shaft 26 through a press-fitting process or a shrink-fitting process.

[0028] The rotor shaft 26 and the rotor core 23 may be fitted together via a key mechanism provided on the periphery of the fixing hole 23a of the rotor core 23 and the outer periphery of the rotor shaft 26. The rotor shaft 26 may have a hollow cylindrical boss structure.

[0029] As described above, rotor core 23 is configured by stacking a large number of electromagnetic steel plates in the axial direction, and eight pairs of magnet insertion holes 29, each consisting of a first magnet insertion hole 29a and a second magnet insertion hole 29b, are arranged symmetrically about a radial imaginary line X that intersects with axis O of rotor core 23, and are arranged at 45-degree intervals around axis O. Note that imaginary line X coincides with the d-axis, which will be described later.

[0030] The first magnet insertion holes 29a and second magnet insertion holes 29b of the eight magnet insertion hole pairs 29 are arranged in a V-shape such that the distance between opposing holes on the radially outer side of the rotor core 23 is greater than the distance between opposing holes on the radially inner side of the rotor core 23. Permanent magnets 24 having a rectangular cross section are inserted into the first magnet insertion holes 29a and second magnet insertion holes 29b of the eight magnet insertion hole pairs 29. Each permanent magnet 24 is formed, for example, from a neodymium rare earth permanent magnet.

[0031] As shown in Figure 2, in one magnet insertion hole pair 29, the permanent magnet 24 inserted into the first magnet insertion hole 29a and the permanent magnet 24 inserted into the second magnet insertion hole 29b are magnetized so that the opposing long sides have the same pole. These two permanent magnets 24 and the first portion 231 of the rotor core sandwiched between these two permanent magnets 24 form one field pole. A total of eight field poles are provided. The rotating electric machine 100 according to embodiment 1 is an eight-pole IPM motor in which a total of 16 permanent magnets 24 are arranged.

[0032] A second portion 232 of the rotor core, which is sandwiched between two adjacent field poles, is provided with a hole 8. The hole 8 is composed of a positioning function portion 8a for positioning the rotor core 23 and a weight-reducing function portion 8b for reducing the weight of the rotor core 23.

[0033] When machining or assembling the rotating electric machine 100, a jig is inserted into the positioning function portion 8a to position the rotor core 23 radially and circumferentially relative to the stator core 13. Note that the positioning function portion 8a may also be used to position the first end plate 25a and the second end plate 25b.

[0034] As will be described later, a rod-shaped positioning member provided on at least one of the first end plate 25a and the second end plate 25b may be inserted into the positioning function portion 8a of the hole portion 8 of the rotor core 23 to position the rotor core 23.

[0035] Normally, to position the rotor core 23, it is necessary to provide at least two positioning holes in the rotor core 23. If the fixing hole 23a in the rotor core 23 for inserting the rotor shaft is used as one of the positioning holes for the rotor core 23, it is sufficient to provide another positioning hole in addition to the fixing hole 23a. However, providing another positioning hole in addition to the fixing hole 23a would affect the rotational balance of the rotor 2.

[0036] Therefore, from the viewpoint of adjusting the rotational balance of the rotor 2 and reducing the weight, it is desirable to provide two or more holes 8 each having a positioning function portion 8a, and to arrange these holes 8 at equal intervals in the circumferential direction of the rotor core 23. In the rotating electric machine according to the first embodiment, the hole portions 8 each consisting of a positioning function portion 8a and a weight-reducing function portion 8b are each formed in the second portion 232 of the rotor core sandwiched between two adjacent field poles, and eight hole portions 8 are provided in total.

[0037] 3 is an explanatory diagram of a rotor for a rotating electric machine according to embodiment 1. In FIG. 3, the radial center of hole 8, which is composed of positioning function portion 8a and weight-reducing function portion 8b, is positioned so as to coincide with q-axis q, which forms an electrical angle of 90° with respect to d-axis d of the rotor core. This configuration allows hole 8 to be positioned substantially midway between two adjacent field poles, thereby preventing imbalance in magnetic flux flow between the two adjacent field poles.

[0038] Hole 8 is provided in a region of rotor core 32 between the periphery of fixing hole 23a and outermost edge 29a1 located on the outermost side of first magnet insertion hole 29a and outermost edge 29b1 located on the outermost side of second magnet insertion hole 29b. Positioning function portion 8a of hole 8 has periphery 8a1 that coincides with part of the arc of an imaginary circle with a diameter d1 [mm] and a center on q-axis.

[0039] In addition, in the first embodiment, the weight-reducing function portion 8b in the hole 8 has a pair of side edges 8b1, 8b2 that extend symmetrically from both ends of the peripheral edge portion 8a1 of the positioning function portion 8a to both sides of the q-axis at an incline, and an inner peripheral edge 8b3 that is connected to the pair of side edges 8b1, 8b2. The inner peripheral edge 8b3 of the weight-reducing function portion 8b is formed linearly and is perpendicular to the q-axis.

[0040] The peripheral edge 8a1 of the positioning function portion 8a is provided on the q-axis side away from an imaginary straight line L1 that is parallel to the long side of the permanent magnet 24 inserted in the first magnet insertion hole 29a and overlaps with a side edge 8b1 of the weight reduction function portion 8b, and further, the peripheral edge 8a1 of the positioning function portion 8a is provided on the q-axis side away from an imaginary straight line (not shown) that is parallel to the long side of the permanent magnet 24 inserted in the second magnet insertion hole 29b and overlaps with a side edge 8b2 of the weight reduction function portion 8b. In other words, the peripheral edge 8a1 of the positioning function portion 8a is not tangent to the above two imaginary straight lines.

[0041] The purpose of providing positioning holes in rotor core 23 is to insert a positioning jig into the positioning holes to position rotor core 23 relative to stator core 13. Therefore, in embodiment 1, the area of ​​hole 8 through which the jig is inserted becomes positioning functional portion 8a, and positioning functional portion 8a essentially corresponds to the hole that contributes to positioning rotor core 23. The area of ​​hole 8 other than positioning functional portion 8a becomes weight-reducing functional portion 8b that contributes to reducing the weight of rotor core 23.

[0042] The shape and size of the positioning function portion 8a are formed to match the shape and size of a rod-shaped positioning portion of a jig used in the positioning step of the rotor core 23. Furthermore, because the weight-reducing function portion 8b is provided for the purpose of reducing the weight of the rotor core 23, the area occupied by the weight-reducing function portion 8b in the hole 8 is set to be larger than the area occupied by the positioning function portion 8a. In other words, when the area occupied by the positioning function portion 8a is S1 and the area occupied by the weight-reducing function portion 8b is S2, the positioning function portion 8a and the weight-reducing function portion 8b are formed so that S2 > S1 holds.

[0043] Second portion 232 of rotor core 23, sandwiched between first magnet insertion hole 29a and second magnet insertion hole 29b, continuously narrows from the inner circumferential side toward the outer circumferential side of rotor core 23. Therefore, in embodiment 1, positioning function portion 8a is arranged on the outer circumferential side of rotor core 23, and weight reduction function portion 8b is arranged on the inner circumferential side of rotor core 23. This makes it easy to form occupied area S2 of weight reduction function portion 8b larger than occupied area S1 of positioning function portion 8a.

[0044] Furthermore, the maximum circumferential width d2 (mm) of the weight-reducing function portion 8b is larger than the maximum circumferential width d1 (mm) of the positioning function portion 8a (i.e., the diameter d1 (mm) of the imaginary circle) (d2 > d1). This configuration reduces the effect on the magnetic flux flowing through the rotor core 23. Furthermore, the rotor core is lightened by the hole 8 formed by the positioning function portion 8a and the weight-reducing function portion 8b, which reduces mechanical loss in the first bearing 27a and the second bearing 27b that rotatably support the rotor shaft 26, thereby improving the efficiency of the rotor 2.

[0045] In the first embodiment, the hole 8 has an outer shape in which the positioning function portion 8 a and the weight-reducing function portion 8 b are separate regions but integrated together, and the positioning function portion 8 a and the weight-reducing function portion 8 b are connected by a smooth curve. This configuration can alleviate stress concentration within the rotor core 23.

[0046] Furthermore, in the first embodiment, it is assumed that a cylindrical rod-shaped jig is used as the jig used to position rotor core 23. Therefore, when the angle range θ of arc-shaped peripheral edge portion 8a1 of positioning function portion 8a is set to a mechanical angle of 180° or more, the area occupied by the imaginary circle indicated by the dashed line that complements peripheral edge portion 8a1 into a perfect arc shape corresponds to positioning function portion 8a, and the remaining area of ​​hole portion 8 excluding the area of ​​positioning function portion 8a corresponds to weight-reducing function portion 8b.

[0047] In the first embodiment, it is assumed that a typical cylindrical rod-shaped jig is used as the jig used in the rotor core positioning step, and the peripheral portion 8a1 of the positioning function portion 8a is made arc-shaped to match the circular cross-sectional shape of the cylindrical jig and to enable it to fit the outer shape of most of the jig. However, the angular range θ of the arc-shaped peripheral portion 8a1 of the positioning function portion 8a is set to 180 mechanical degrees or more. However, the peripheral portion 8a1 of the positioning function portion 8a is not limited to such an arc-shaped shape and can have an optimal shape depending on the cross-sectional shape of the positioning jig. For example, when a positioning jig having an elliptical or rectangular cross-sectional shape is used, at least a portion of the shape of the peripheral portion 8a1 of the positioning function portion 8a can be made to fit the outer shape of the ellipse or rectangle.

[0048] The weight-saving functional portion 8b is designed to have a relatively large occupied area S2 in order to reduce the weight of the rotor core 23. Therefore, if all of the weight-saving functional portion 8b were located in the area between adjacent magnet insertion holes, it would impede the flow of magnetic flux in the rotor core 23, which would be detrimental to the characteristics of the rotating electric machine. On the other hand, if the weight-saving functional portion 8b were located on the inner diameter side closer to the fixing holes 23a of the rotor core 23, it would result in a decrease in the strength of the rotor core 23. Therefore, it is desirable that the occupied area of ​​the weight-saving functional portion 8b in the area between adjacent magnet insertion holes be kept as small as possible and that the weight-saving functional portion 8b be located in an area as far away as possible from the fixing holes 23a of the rotor core 23.

[0049] In the first portion 231 of the rotor core 23 that constitutes the field pole, the central axis between the two opposing permanent magnets 24 inserted into the first magnet insertion hole 29a and the second magnet insertion hole 29b is the d-axis, and the central axis between this d-axis and another adjacent d-axis is the q-axis. The q-axis coincides with the central axis of the second portion 232 of the rotor core 23 that is sandwiched between the two adjacent pairs of magnet insertion holes 29.

[0050] The center of the hole 8 is located on the q-axis. With this configuration, the hole 8 can be provided substantially in the middle between two adjacent field poles, preventing imbalance in the magnetic flux flow between the two adjacent magnetic poles.

[0051] It is desirable to arrange the holes 8 symmetrically with respect to the q-axis from the viewpoint of the rotational balance of the rotor 2. When the shortest inter-pole distance, which is the distance from the first magnet insertion hole 29a in one field pole to the second magnet insertion hole 29b in the adjacent field pole, is d3 [mm], if there is an area in the rotor core 23 where the width through which the magnetic flux passes is smaller than the shortest inter-pole distance d3 [mm], magnetic loss in the rotor core 23 increases.

[0052] For this reason, as described above, the shortest distance d4 [mm] between the magnet insertion holes and the holes, more specifically, the shortest distance d4 [mm] between first magnet insertion hole 29 a and hole 8 and the shortest distance d4 [mm] (not shown) between second magnet insertion hole 29 b and hole 8, is set to be equal to or greater than the shortest magnetic pole-to-pole distance d3 [mm] (d4≧d3). This configuration reduces the effect on the magnetic flux flowing through rotor core 23, and prevents a decrease in the efficiency of rotor 2.

[0053] To maximize the weight reduction effect while suppressing magnetic loss, the shortest distance d4 (mm) between the magnet insertion hole and the hole 8 and the shortest magnetic pole-to-pole distance d3 (mm) should be the same. Furthermore, stress due to the engagement between the rotor core 23 and the rotor shaft 26 and stress due to centrifugal force resulting from the rotation of the rotor 2 are generated on the inner peripheral edge 8b3 of the weight-reducing functional portion 8b. Therefore, it is desirable to calculate in advance the stress due to the engagement between the rotor core 23 and the rotor shaft 26 and the stress due to centrifugal force resulting from the rotation of the rotor 2, and then determine the optimal distance from the peripheral edge of the fixing hole 23a of the rotor core 23 to the inner peripheral edge 8b3 of the weight-reducing functional portion 8b based on the calculation results. Setting this optimal distance can suppress the effects of stress on the inner peripheral edge 8b3 of the weight-reducing functional portion 8b.

[0054] According to the rotating electric machine of the first embodiment, the hole portion has little effect on the magnetic flux and has the functions of positioning and reducing mass, thereby reducing mechanical loss in the bearing portion and improving the efficiency of the rotor.

[0055] Second Embodiment Next, a rotating electric machine according to the second embodiment will be described, focusing on the configuration of the hole. FIG. 4 is an explanatory diagram of a rotor of the rotating electric machine according to the second embodiment. In FIG. 4, hole 8, which is composed of positioning function portion 8a and weight reduction function portion 8b, is provided so that its center line coincides with the q-axis, as in the first embodiment. By configuring hole 8 in this manner, hole 8 can be provided substantially in the middle between two adjacent field poles, and imbalance of magnetic flux flow between the two adjacent field poles can be prevented.

[0056] In addition, the shortest distance d4 [mm] between the magnet insertion hole and the hole portion, more specifically, the shortest distance d4 [mm] between the first magnet insertion hole 29a and the hole portion 8 and the shortest distance d4 [mm] between the second magnet insertion hole 29b and the hole portion 8 (not shown) are formed to be greater than the shortest magnetic pole-to-pole distance d3 [mm] (d4≧d3).

[0057] The peripheral edge 8a1 of the positioning function portion 8a is provided on the q-axis side away from an imaginary straight line L1 that is parallel to the long side of the permanent magnet 24 inserted in the first magnet insertion hole 29a and overlaps with one side edge 8b1 of the weight reduction function portion 8b. Furthermore, the peripheral edge 8a1 of the positioning function portion 8a is provided on the q-axis side away from an imaginary straight line (not shown) that is parallel to the long side of the permanent magnet 24 inserted in the second magnet insertion hole 29b and overlaps with the other side edge 8b2 of the weight reduction function portion 8b.

[0058] One side edge 8b1 of the weight-reducing function portion 8b is connected to one end of the peripheral edge 8a1 of the positioning function portion 8a via one outer peripheral edge 8b4 parallel to the inner peripheral edge 8b3, and the other side edge 8b2 of the weight-reducing function portion 8b is connected to the other end of the peripheral edge 8a1 of the positioning function portion 8a via the other outer peripheral edge 8b5 parallel to the inner peripheral edge 8b3.

[0059] One side edge 8b1 of the weight-reducing function portion 8b overlaps an imaginary line L1 that is parallel to the long side of the permanent magnet 24 inserted into the first magnet insertion hole 29a, and the other side edge 8b2 of the weight-reducing function portion 8b overlaps an imaginary line (not shown) that is parallel to the long side of the permanent magnet 24 inserted into the second magnet insertion hole 29b. This configuration makes it possible to increase the occupation area of ​​the hole 8 while suppressing magnetic loss in the rotor 2.

[0060] Other configurations of the rotating electric machine according to the second embodiment are similar to those of the rotating electric machine according to the first embodiment.

[0061] According to the rotating electric machine of the second embodiment, the hole portion has little effect on the magnetic flux and functions to position and reduce mass, thereby reducing mechanical loss in the bearing portion and improving rotor efficiency.

[0062] Third Embodiment Next, a rotating electric machine according to a third embodiment will be described, focusing on the configuration of the hole. FIG. 5 is an explanatory diagram of a rotor of a rotating electric machine according to the third embodiment. In FIG. 5, hole 8, which is composed of positioning function portion 8a and weight reduction function portion 8b, is provided so that its center line coincides with the q-axis, as in the first embodiment. By configuring hole 8 in this manner, hole 8 can be provided substantially in the middle between two adjacent field poles, and imbalance of magnetic flux flow between the two adjacent field poles can be prevented.

[0063] The shortest distance d4 [mm] between the magnet insertion hole and the hole portion, i.e., the shortest distance d4 [mm] between the first magnet insertion hole 29a and the hole portion 8, and the shortest distance d4 [mm] between the second magnet insertion hole 29b and the hole portion 8 (not shown) are configured to be greater than the shortest magnetic pole-to-pole distance d3 [mm] (d4≧d3).

[0064] The peripheral edge 8a1 of the positioning function portion 8a is in contact with an imaginary line L1 that is parallel to the long side of the permanent magnet 24 inserted in the first magnet insertion hole 29a and overlaps with one side edge 8b1 of the weight reduction function portion 8b. Furthermore, the peripheral edge 8a1 of the positioning function portion 8a is in contact with an imaginary line (not shown) that is parallel to the long side of the permanent magnet 24 inserted in the second magnet insertion hole 29b and overlaps with the other side edge 8b2 of the weight reduction function portion 8b.

[0065] One side edge 8b1 of the weight-reducing function portion 8b is connected to one end of the peripheral edge 8a1 of the positioning function portion 8a via one outer peripheral edge 8b4 parallel to the inner peripheral edge 8b3, and the other side edge 8b2 of the weight-reducing function portion 8b is connected to the other end of the peripheral edge 8a1 of the positioning function portion 8a via the other outer peripheral edge 8b5 parallel to the inner peripheral edge 8b3.

[0066] One side edge 8b1 of the weight-reducing functional portion 8b overlaps the imaginary line L1, and the other side edge 8b2 of the weight-reducing functional portion 8b overlaps an imaginary line parallel to the long side of the permanent magnet 24 inserted in the second magnet insertion hole 29b. With this configuration, it is possible to increase the occupation area of ​​the hole 8 while suppressing magnetic loss in the rotor 2.

[0067] Other configurations of the rotating electric machine according to the third embodiment are similar to those of the rotating electric machine according to the first embodiment.

[0068] According to the rotating electrical machine of the third embodiment, the holes have little effect on the magnetic flux and serve to position the rotor and reduce its mass, thereby reducing mechanical loss in the bearing portion and improving the efficiency of the rotor.

[0069] Fourth Embodiment Next, a rotating electric machine according to a fourth embodiment will be described, focusing on the configuration of the hole. Figure 6 is an explanatory diagram of a rotor of the rotating electric machine according to the fourth embodiment. In Figure 6, hole 8, which is composed of positioning function portion 8a and weight reduction function portion 8b, is positioned so that its center line coincides with the d-axis. Furthermore, hole 8 is positioned on the inner periphery of first portion 231 of rotor core 23, which constitutes the field pole, i.e., between inner periphery edge 29a2 of first magnet insertion hole 29a and inner periphery edge 29b2 of second magnet insertion hole 29b.

[0070] One side edge 8b1 of the weight-reducing function portion 8b is connected to one end of the peripheral edge 8a1 of the positioning function portion 8a via one outer peripheral edge 8b4 parallel to the inner peripheral edge 8b3, and the other side edge 8b2 of the weight-reducing function portion 8b is connected to the other end of the peripheral edge 8a1 of the positioning function portion 8a via the other outer peripheral edge 8b5 parallel to the inner peripheral edge 8b3.

[0071] One side edge 8b1 of the weight-reducing function portion 8b faces the inner peripheral edge 29b2 of the second magnet insertion hole 29b at a predetermined distance, and the other side edge 8b2 of the weight-reducing function portion 8b faces the inner peripheral edge 29a2 of the first magnet insertion hole 29a at a predetermined distance. The predetermined distance is set to the minimum value that suppresses the effect on the flow of magnetic flux of the field poles and allows the rotor core 23 to maintain the strength required.

[0072] Other configurations of the rotating electric machine according to the fourth embodiment are similar to those of the rotating electric machine according to the first embodiment.

[0073] According to the rotating electric machine of the fourth embodiment, the holes have little effect on the magnetic flux and serve to position the rotor and reduce its mass, thereby reducing mechanical loss in the bearing portion and improving the efficiency of the rotor.

[0074] Fifth Embodiment Next, a rotating electric machine according to the fifth embodiment will be described. Figure 7 is an explanatory diagram of a rotor of the rotating electric machine according to the fifth embodiment. In the rotating electric machine according to the fifth embodiment, a first magnet insertion hole step 291 and a second magnet insertion hole step 292 are arranged in a stepped manner, left-right symmetrically with respect to the d-axis, and radially from the inner periphery toward the outer periphery of the rotor core 23, in a first portion 231 of the rotor core 23 that constitutes one field pole. The first magnet insertion hole step 291 is provided closer to the inner periphery of the rotor core 23 than the second magnet insertion hole step 292.

[0075] The first magnet insertion hole stage 291 is composed of a first magnet insertion hole 29 a and a second magnet insertion hole 29 b, and the second magnet insertion hole stage 292 is composed of a third magnet insertion hole 29 c and a fourth magnet insertion hole 29 d. A first permanent magnet 241 is inserted into the first magnet insertion hole 29 a and the second magnet insertion hole 29 b, and a second permanent magnet 242 is inserted into the third magnet insertion hole 29 c and the fourth magnet insertion hole 29 d.

[0076] Hole 8, which is composed of positioning function portion 8a and weight-reducing function portion 8b, is positioned so that its center line coincides with the d-axis. Hole 8 is provided in a portion of rotor core 23 where inner peripheral edge 29a2 of first magnet insertion hole 29a faces inner peripheral edge 29b2 of second magnet insertion hole 29b.

[0077] One side edge 8b1 of the weight-reducing function portion 8b is connected to one end of the peripheral edge 8a1 of the positioning function portion 8a via one outer peripheral edge 8b4 parallel to the inner peripheral edge 8b3, and the other side edge 8b2 of the weight-reducing function portion 8b is connected to the other end of the peripheral edge 8a1 of the positioning function portion 8a via the other outer peripheral edge 8b5 parallel to the inner peripheral edge 8b3.

[0078] One side edge 8b1 of the weight-reducing function portion 8b faces the inner peripheral edge 29b2 of the second magnet insertion hole 29b at a predetermined distance, and the other side edge 8b2 of the weight-reducing function portion 8b faces the inner peripheral edge 29a2 of the first magnet insertion hole 29a at a predetermined distance. The predetermined distance is set to the minimum value that suppresses the effect on the flow of magnetic flux of the field poles and allows the rotor core 23 to maintain the strength required.

[0079] The distance d5 [mm] between the outermost edge 29a1 of the first magnet insertion hole 29a and the outermost edge 29c1 of the third magnet insertion hole 29c, and the distance d5 [mm] between the outermost edge 29b1 of the second magnet insertion hole 29b and the outermost edge 29d1 of the fourth magnet insertion hole 29d, are the shortest distance between the magnet insertion hole stages, which is the shortest distance between the first magnet insertion hole stage 291 and the second magnet insertion hole stage 292 within the magnetic pole.

[0080] Here, CX denotes an imaginary circle tangent to the inner peripheral edge 29c2 of the third magnet insertion hole 29c and the inner peripheral edge 29d2 of the fourth magnet insertion hole 29d in the second magnet insertion hole step 292 provided on the outer peripheral side of the rotor core 23. The shortest distance d6 [mm] between the arc of the imaginary circle CX and the peripheral edge 8a1 of the positioning function portion 8a of the hole 8 is set to be equal to or greater than the shortest inter-magnet insertion step distance d5 (d6≧d5). With this configuration, there is no region of the rotor core 23 in the first portion 231 of the rotor core 23 that is narrower than the shortest inter-magnet insertion hole step distance d5, preventing an increase in magnetic loss.

[0081] In the fifth embodiment shown in Figure 7, the magnet insertion hole stage is configured as two stages, the first magnet insertion hole stage 291 and the second magnet insertion hole stage 292, but it may also be configured as three or more stages.

[0082] Furthermore, holes each having a positioning function and a weight-reducing function may be provided on the d-axis of all of two or more magnet insertion hole stages. In this case, the configuration of the magnet insertion hole stage located on the outermost peripheral side of rotor core 23 will be the same as the configuration of the magnet insertion holes and holes in the fourth embodiment shown in Figure 6.

[0083] Other configurations of the rotating electric machine according to embodiment 5 are similar to those of the rotating electric machine according to embodiment 1. However, the vertical cross-sectional view of FIG.

[0084] According to the rotating electric machine of the fifth embodiment described above, the holes that have little effect on the magnetic flux and have the functions of positioning and reducing mass reduce mechanical loss in the bearing portion, thereby improving rotor efficiency.

[0085] Sixth Embodiment Next, a rotating electric machine according to a sixth embodiment will be described. Fig. 8 is an explanatory diagram of a rotor of the rotating electric machine according to the sixth embodiment. According to the rotating electric machine according to the sixth embodiment, the positioning function portion 8a of the hole portion 8 is disposed on the inner diameter side of the rotor core 23 relative to the weight reduction function portion 8b, and faces the fixing hole 23a of the rotor core 23.

[0086] On the inner periphery of the rotor core at the hole, stresses are generated due to the engagement between the rotor core 23 and the rotor shaft 26, as well as stresses due to the centrifugal force of the rotor 2. However, if calculations show that these stresses are relatively small, it is possible to position the positioning function part 8a on the inner periphery of the rotor core 23.

[0087] Hole 8, which is made up of positioning function portion 8a and weight-reducing function portion 8b, is provided so that its center line coincides with the q-axis. By configuring it in this manner, hole 8 can be provided substantially in the middle between two adjacent field poles, preventing imbalance in magnetic flux flow between the two adjacent field poles.

[0088] One side edge 8b6 of the weight-reducing function portion 8b is connected to one end of the peripheral edge 8a1 of the positioning function portion 8a via one inner side edge 8b9 parallel to the outer side edge 8b8, and the other side edge 8b7 of the weight-reducing function portion 8b is connected to the other end of the peripheral edge 8a1 of the positioning function portion 8a via the other inner side edge 8b10 parallel to the outer side edge 8b8.

[0089] One side edge 8b6 of weight-saving function portion 8b extends parallel to the long side of permanent magnet 24 inserted in second magnet insertion hole 29b, and the other side edge 8b7 of weight-saving function portion 8b extends parallel to the long side of permanent magnet 24 inserted in first magnet insertion hole 29a. The shortest distance d4 [mm] between the magnet insertion hole and the hole, i.e., the shortest distance d4 [mm] between first magnet insertion hole 29a and hole 8, and the shortest distance d4 [mm] between second magnet insertion hole 29b and hole 8 are configured to be equal to or greater than the shortest magnetic pole-to-pole distance d3 [mm] (d4≧d3).

[0090] By adopting such a configuration, it is possible to increase the area occupied by the hole 8 while suppressing magnetic loss in the rotor 2 .

[0091] Other configurations of the rotating electric machine according to the sixth embodiment are similar to those of the rotating electric machine according to the first embodiment.

[0092] According to the rotating electric machine of the sixth embodiment, the holes have little effect on the magnetic flux and serve to position the rotor and reduce its mass, thereby reducing mechanical loss in the bearing portion and improving the efficiency of the rotor.

[0093] Seventh Embodiment Next, a rotating electric machine according to a seventh embodiment will be described. Fig. 9 is an explanatory diagram of a rotor of the rotating electric machine according to the seventh embodiment. As shown in Fig. 9, in the rotating electric machine according to the seventh embodiment, the inner peripheral edge portion 8b3 of the weight-reducing functional portion 8b of the hole portion 8 is configured in an arc shape that bulges toward the inside in the radial direction of the rotor core 23. The other configurations are the same as those of the rotating electric machine according to the third embodiment shown in Fig. 5.

[0094] As mentioned above, the inner peripheral edge 8b3 of the weight-reducing functional portion 8b of the hole portion 8 is subjected to stress due to the engagement between the rotor core 23 and the rotor shaft 26, as well as stress due to the centrifugal force caused by the rotation of the rotor 2. However, according to the rotating electric machine of embodiment 7, the inner peripheral edge 8b3 of the weight-reducing functional portion 8b is configured in an arc shape that bulges radially inward of the rotor core 23, thereby reducing the aforementioned stress applied to the inner peripheral edge 8b3 formed in an arc shape.

[0095] According to the rotating electric machine of the seventh embodiment described above, the holes that have little effect on the magnetic flux and have the functions of positioning and reducing mass reduce the mechanical loss of the bearing portion, thereby improving the efficiency of the rotor.

[0096] Embodiment 8 Next, a rotating electric machine according to embodiment 8 will be described. The rotating electric machine according to embodiment 8 is configured such that at least one of a first end plate 25a abutting against one axial end of the rotor core 23 and a second end plate 25b abutting against the other axial end of the rotor core 23 is provided with a plurality of rod-shaped positioning members (not shown) extending in the axial direction of the rotor core 23, and the positioning members are inserted into positioning functional portions 8a in holes 8 formed in the rotor core 23.

[0097] The multiple rod-shaped positioning members provided on the end plate have a cross-sectional shape that matches the shape of the positioning functional parts 8a in the holes 8 of the rotor core 23. The multiple rod-shaped positioning members are also arranged at circumferential intervals that match the circumferential intervals of the rotor core 23 between the multiple positioning functional parts 8a to be inserted.

[0098] Here, it is determined in advance which of the positioning function portions 8a of the plurality of holes in the rotor core 23 the plurality of rod-shaped positioning members will be inserted into, and the spacing between the plurality of rod-shaped positioning members is set to match the spacing between the plurality of positioning function portions 8a to be inserted. Note that the end plate may be configured so that the spacing between the plurality of rod-shaped positioning members can be adjusted to match the spacing between the plurality of positioning function portions 8a to be inserted.

[0099] The rod-shaped positioning members provided on the end plates are formed so that their cross-sectional shapes match the cross-sectional shapes of the positioning function parts 8 a into which they are to be inserted. The positioning members are also set so that they can be inserted into the positioning function parts 8 a of the holes 8 of the rotor core 23 with a degree of play that falls within an allowable range.

[0100] The engagement of the rod-shaped positioning members on the end plates with the positioning functional portions 8a of the holes 8 in the rotor core 23 enables the two-dimensional radial arrangement of the rotor 2 relative to the stator 1 and the alignment of the axes of the stator 1 and the rotor 2. Note that, if the engagement accuracy between the rod-shaped positioning members on the end plates and the positioning functional portions 8a of the holes 8 in the rotor core 23 is within an allowable range, the rotor 2 can be roughly positioned relative to the stator 1 within an allowable range.

[0101] Ninth Embodiment Next, a method for manufacturing a rotating electric machine according to the ninth embodiment will be described. The method for manufacturing a rotating electric machine according to the ninth embodiment is a method for manufacturing a rotating electric machine in which the rotating electric machine according to any one of the above-described first to seventh embodiments is manufactured by aligning the axes of the stator core and the rotor core using a positioning function portion in the hole of rotor core 23 and an axis alignment jig.

[0102] The axial alignment jig includes a rotor core positioning portion that positions the rotor core relative to the stator core, and a stator core holding portion that holds the stator core. The stator core holding portion is disposed around the rotor core positioning portion and is configured, for example, by a clamping mechanism, and holds the stator core 13 in a predetermined position.

[0103] The rotor core positioning portion is composed of multiple rod-shaped positioning members that are inserted into positioning functional portions 8a of holes 8 provided in rotor core 23 to hold rotor core 23, thereby aligning the axis of stator core 13 with the axis of rotor core 23 and radially positioning rotor core 23 relative to stator core 13. The positioning jig is designed to align the axis of the stator core with the axis of the rotor core within a predetermined error range.

[0104] The multiple rod-shaped positioning members that make up the rotor core positioning portion have a cross-sectional shape that matches the shape of the positioning function portions 8a in the holes 8 of the rotor core 23. The multiple rod-shaped positioning members are also arranged at circumferential intervals that match the circumferential intervals of the rotor core 23 between the multiple positioning function portions 8a that are to be inserted.

[0105] Here, the spacing between the multiple rod-shaped rotor core positioning members is set so as to match the spacing between the multiple positioning function parts 8a that are set in advance regarding which of the multiple hole parts 8 in the rotor core 23 the positioning members will be inserted into. Note that the rotor core positioning part may be configured so that the spacing between the multiple rod-shaped positioning members can be adjusted to match the spacing between the multiple positioning function parts 8a to be inserted.

[0106] The manufacturing method of a rotating electric machine according to embodiment 9 is a manufacturing method of a rotating electric machine for manufacturing a rotating electric machine described in any one of embodiments 1 to 7, and includes: a stator core holding process for holding the stator core by a stator holding portion of an axial alignment jig; a rotor core positioning process for inserting multiple rod-shaped positioning members in the rotor core positioning portion of the axial alignment jig into positioning function portions in the hole portions of the rotor core to position the rotor relative to the stator; and an assembly process for assembling at least a portion of the rotating electric machine in a state in which the rotor core has been positioned relative to the stator core by the rotor core positioning process.

[0107] It is advantageous to perform the stator core holding process before the rotor core positioning process in order to prevent interference between the stator core 13 and the rotor core 23, but if there is no particular problem with interference between the stator core 13 and the rotor core 23, either the stator core holding process or the rotor core positioning process may be performed first.

[0108] According to the manufacturing method of a rotating electric machine according to embodiment 9, by using a positioning function part in the hole portion of the rotor core and an axial center alignment jig, it is possible to obtain a rotating electric machine that can reduce costs during manufacturing and improve the efficiency of the rotating electric machine.

[0109] Tenth Embodiment Next, a method for manufacturing a rotating electric machine according to a tenth embodiment will be described. The tenth embodiment relates to a method for manufacturing a rotating electric machine according to any one of the first to seventh embodiments, in which, when at least one of the first and second end plates is provided with a hole having a positioning function portion that is at least the same as the positioning function portion in the hole provided in the rotor core, the rotating electric machine is manufactured using the positioning function portion of the end plate and the positioning function portion of the rotor core.

[0110] The manufacturing method of a rotating electric machine according to embodiment 10 is a manufacturing method of a rotating electric machine in which the end plate is positioned relative to the rotor core 23 by inserting multiple rod-shaped positioning portions provided on a jig into both the positioning function portion in the hole portion provided in the end plate and the positioning function portion 8a in the hole portion 8 provided in the rotor core.

[0111] According to the manufacturing method of a rotating electric machine according to embodiment 10, by using positioning function parts in the hole portions of the end plates and the rotor core, and a positioning jig, it is possible to obtain a rotating electric machine that can reduce costs during manufacturing and improve the efficiency of the rotating electric machine.

[0112] Embodiment 11 Next, a method for manufacturing a rotating electric machine according to embodiment 11 will be described. The method for manufacturing a rotating electric machine according to embodiment 11 is a method for manufacturing a rotating electric machine in which the rotating electric machine according to embodiment 8 described above is configured such that the end plates and the rotor core are aligned using positioning function portions in the holes of the rotor core and end plates attached to the axial ends of the rotor core.

[0113] The manufacturing method of a rotating electric machine according to embodiment 11 is a manufacturing method of a rotating electric machine in which the end plate and the rotor core are positioned by inserting a plurality of rod-shaped positioning members provided on the end plate into the positioning function portion 8a in the hole portion 8 provided in the rotor core 23.

[0114] According to the manufacturing method of the rotating electric machine of the embodiment 11 described above, by using a positioning function portion in the hole portion of the rotor core and an end plate having a plurality of columnar protrusions, it is possible to obtain a rotating electric machine that can reduce costs during manufacturing and improve the efficiency of the rotating electric machine.

[0115] The positioning function portions of the holes in the rotating electric machines according to the first to eighth embodiments are basically provided for use when aligning the axes of the rotor and stator, or when aligning the rotor core and end plates. However, for example, due to the commonality of rotor component designs, rotating electric machines that are not manufactured according to the ninth to eleventh embodiments may also use rotor cores having the positioning function portions as common components with the rotating electric machines manufactured according to the ninth to eleventh embodiments.

[0116] Although various exemplary embodiments are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology of this disclosure. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0117] 100 Rotating electric machine, 1 Stator, 12 Frame, 12a Flange, 13 Stator core, 14 Stator coil, 2 Rotor, 23 Rotor core, 23a Fixing hole, 231 First portion of rotor core, 232 Second portion of rotor core, 24 Permanent magnet, 241 First permanent magnet, 242 Second permanent magnet, 25a First end plate, 25b Second end plate, 26 Rotor shaft, 27a First bearing, 27b Second bearing, 28 Stopper, 29 Magnet insertion hole pair, 291 First magnet insertion hole step, 292 Second magnet insertion hole step, 29a First magnet insertion hole, 29b Second magnet insertion hole, 29c Third magnet insertion hole, 29d Fourth magnet insertion hole, 29a1, 29b1 Outermost peripheral edge portion, 29a2, 29b2 inner peripheral edge portion, 8 hole portion, 8a positioning function portion, 8a1 peripheral edge portion, 8b weight reduction function portion, 8b1, 8b2, 8b6, 8b7 side edge portions, 8b3, 8b9, 8b10 inner peripheral edge portion, 8b4, 8b5, 8b8 outer peripheral edge portion

Claims

1. A rotating electric machine comprising: a stator core formed in an annular shape; a stator coil attached to the stator core; a rotor core whose outer peripheral surface faces an inner peripheral surface of the stator core via a gap and has a plurality of magnet insertion holes; a plurality of permanent magnets inserted into the magnet insertion holes respectively to form a plurality of field poles in the rotor core; a rotor shaft that passes through a fixing hole provided in the radial center of the rotor core and supports the rotor core; and a bearing that rotatably supports the rotor shaft, wherein the rotor core has a hole portion formed between the fixing hole and the outermost peripheral edge of the magnet insertion hole, and the hole portion is composed of a positioning function portion that contributes to positioning the rotor core, and a weight reduction function portion that contributes to reducing the weight of the rotor core.

2. A rotating electric machine as claimed in claim 1, characterized in that, when the occupied area of ​​the positioning function portion is S1 and the occupied area of ​​the weight reduction function portion is S2, the hole portion is formed so that S2 > S1 holds.

3. A rotating electric machine according to claim 1 or 2, characterized in that the positioning function portion has an arc-shaped peripheral portion.

4. A rotating electric machine according to claim 3, characterized in that the arc-shaped peripheral portion of the positioning function portion is constituted by an arc portion having an angular range of a mechanical angle of 180° or more.

5. A rotating electric machine as claimed in claim 3 or 4, characterized in that, when the diameter of the arc-shaped peripheral portion of the positioning function portion is d1 and the maximum width of the rotor core in the circumferential direction of the weight-reduction function portion is d2, the hole portion is formed so that d2 > d1 holds.

6. A rotating electric machine as claimed in any one of claims 1 to 5, characterized in that the hole is arranged on the q axis of the field pole, and when the shortest magnetic pole-to-pole distance between two adjacent field poles is d3 and the shortest distance between the magnet insertion hole and the hole is d4, the rotor core is configured so that d4 ≧ d3 holds.

7. A rotating electric motor as described in claim 6, characterized in that the weight-reducing functional portion of the hole has a side edge portion extending parallel to the long side of the permanent magnet, and the side edge portion of the weight-reducing functional portion is formed so as to overlap with an imaginary straight line L1 extending parallel to the long side of the permanent magnet via d4.

8. A rotating electric machine according to claim 7, characterized in that the positioning function portion of the hole has an arc-shaped peripheral portion, and the arc-shaped peripheral portion is formed so as to be tangent to the imaginary straight line L1.

9. A rotating electric motor as claimed in any one of claims 1 to 5, characterized in that the hole is arranged on the d-axis of the field pole, and is formed in a portion of the rotor core where two adjacent magnet insertion holes in the field pole face each other on the radially inner side of the rotor core.

10. The rotating electric machine of claim 9, characterized in that the rotor core comprises: a first magnet insertion hole stage; and a second magnet insertion hole stage arranged on the outer periphery of the rotor core relative to the first magnet insertion hole stage, the first magnet insertion hole stage being constituted by a first magnet insertion hole and a second magnet insertion hole arranged symmetrically with respect to a virtual line extending radially of the rotor core, the second magnet insertion hole stage being constituted by a third magnet insertion hole and a fourth magnet insertion hole arranged symmetrically with respect to the virtual line, the multiple field poles being respectively formed by permanent magnets inserted into the first magnet insertion hole and the second magnet insertion hole, and permanent magnets inserted into the third magnet insertion hole and the fourth magnet insertion hole, the hole portion being formed between the fixing hole and the outermost peripheral edge portions of the third magnet insertion hole and the fourth magnet insertion hole.

11. A rotating electric machine according to any one of claims 1 to 8, characterized in that the positioning function portion is arranged on the outer periphery side of the rotor core relative to the weight reduction function portion.

12. A rotating electric machine as described in any one of claims 3 to 5 and 8, characterized in that the weight-saving function portion is arranged on the outer periphery side of the rotor core relative to the positioning function portion, and the arc-shaped peripheral portion of the positioning function portion is arranged to face the fixing hole of the rotor core.

13. A rotating electric machine as described in any one of claims 1 to 12, characterized in that at least one axial end of the rotor core is provided with an end plate that abuts against the rotor core in the axial direction, and the end plate is provided with a hole having a positioning function portion that matches at least the positioning function portion in the hole formed in the rotor core.

14. A rotating electric machine as described in any one of claims 1 to 12, characterized in that at least one axial end of the rotor core is provided with an end plate that abuts against the rotor core in the axial direction, the end plate is provided with a plurality of rod-shaped positioning members extending in the axial direction of the rotor core, and the plurality of positioning members are inserted into at least the positioning functional portions in the plurality of holes formed in the rotor core.

15. A method for manufacturing a rotating electric machine according to any one of claims 1 to 12, comprising: a stator core holding step of holding the stator core with a stator core holding portion of an axial alignment jig; a rotor core positioning step of inserting a plurality of rod-shaped positioning members in a rotor core positioning portion of the axial alignment jig into the positioning functional portion in the hole portion of the rotor core to position the rotor core relative to the stator core; and an assembly step of assembling at least a portion of the rotating electric machine in a state in which the rotor core has been positioned relative to the stator core by the rotor core positioning step.

16. A method for manufacturing a rotating electric machine for manufacturing the rotating electric machine described in claim 13, comprising: a stator core holding step of holding the stator core with a stator core holding portion of an axial alignment jig; a rotor core positioning step of inserting a plurality of rod-shaped positioning members in a rotor core positioning portion of the axial alignment jig into the positioning functional portions in the holes provided in the end plates and the positioning functional portions in the holes provided in the rotor core, thereby positioning the rotor core relative to the stator core; and an assembly step of assembling at least a portion of the rotating electric machine in a state in which the rotor core has been positioned relative to the stator core by the rotor core positioning step.

17. A method for manufacturing a rotating electric machine for manufacturing the rotating electric machine described in claim 13, characterized in that positioning between the end plate and the rotor core is performed by inserting a plurality of rod-shaped positioning parts provided on a jig into both the positioning function part in the hole provided in the end plate and the positioning function part in the hole provided in the rotor core.

18. A method for manufacturing a rotating electric machine according to claim 14, characterized in that positioning between the end plate and the rotor core is performed by inserting the multiple rod-shaped positioning members provided on the end plate into the positioning functional portion in the hole portion provided in the rotor core.

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