Rotor for rotary electric machine

Abstract

To provide a rotor for a rotary electric machine to improve the cooling effect of permanent magnets in the rotary electric machine.SOLUTION: A rotor 1 for a rotary electric machine includes a rotor core 10 with a magnet accommodating hole 31 extending in an axial direction, a permanent magnet 32 accommodated in the magnet accommodating hole 31, and a cover 40 arranged opposite an axial end face 11 of the rotor core 10. An inner end face 401 of the cover 40 has an inner end face 421 of a ring portion 42 abutting the axial end face 11 of the rotor core 10, and an inner end face 411 of a plate portion 41 spaced from the axial end face 11. Through holes 431 and 432 are provided in the cover 40. An axial end of the permanent magnet 32 protrudes axially outward from the axial end face 11 of the rotor core 10, and axial end faces 32a and 32b of the permanent magnet 32 are located axially outward from the inner end face 411 of the plate portion 41.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, there has been known a rotating electric machine that includes magnets housed in a rotor core along the axial direction, an end plate disposed in contact with the axial end face of the rotor core, and a cooling medium that flows between the end face of the rotor core and a groove provided in the end plate (see, for example, Patent Document 1). In the rotating electric machine described in Patent Document 1, the axial end face of the magnet is disposed on the same plane as the axial end face of the rotor core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-170877 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the axial end face of the magnet is arranged flush with the axial end face of the rotor core, as described in Patent Document 1, it is difficult to sufficiently cool the magnet by the flow of cooling medium between the rotor core and the end plate. [Means for solving the problem]

[0005] A rotor for a rotating electric machine according to one aspect of the present invention includes a rotor core having a generally cylindrical shape centered on an axis and magnet accommodating holes extending in the axial direction, magnets accommodated in the magnet accommodating holes, and a flow path forming member arranged opposite the axial end face of the rotor core so as to form a flow path for a coolant between the axial end face and the rotor core. The flow path forming member has an inner end face on the inner side in the axial direction and an outer end face on the outer side in the axial direction, the inner end face having a first end face abutting the axial end face of the rotor core and a second end face spaced from the axial end face of the rotor core, the flow path forming member is provided with a through hole extending from the second end face to the outer end face, and the axial ends of the magnets protrude axially outward from the axial end face of the rotor core, and the axial end faces of the magnets are located axially outer than the second end face. [Effects of the Invention]

[0006] According to the present invention, the magnets included in the rotor for a rotating electric machine can be cooled sufficiently. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view perpendicular to an axis, showing a configuration of a main part of a rotating electric machine having a rotor for a rotating electric machine according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view of the rotor taken along line II-II in FIG. 1. [Figure 3] FIG. 2 is an enlarged view of a main part of FIG. 1 showing the configuration of a single magnetic pole part. [Figure 4] FIG. 2 is a perspective view of the cover of FIG. 1 alone. [Figure 5] FIG. 2 is a diagram schematically illustrating a flow of a cooling medium around a rotor for a rotating electric machine according to an embodiment of the present invention. [Figure 6] FIG. 3 is a diagram showing a modification of FIG. 2. [Figure 7] FIG. 4 is a diagram showing a modification of FIG. 3; [Figure 8] FIG. 10 is a perspective view of the axial end of an inner diameter side permanent magnet having an uneven end surface. [Figure 9] FIG. 9 is a front view of a rotor core including the inner diameter side permanent magnets of FIG. 8. [Figure 10] FIG. 10 is a diagram showing a modification of FIG. 9; [Figure 11] FIG. 11 is a perspective view of the rotor of FIG. 10 . DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 11. A rotor for a rotating electric machine according to an embodiment of the present invention can be used in various rotating electric machines. For example, it can be installed in a hybrid vehicle or an electric vehicle and used as a rotating electric machine such as a motor or generator for driving the vehicle. Note that the rotating electric machine can also be installed in a vehicle and used for various purposes.

[0009] Fig. 1 is a cross-sectional view perpendicular to an axis CL0 showing the configuration of a main part of a rotating electric machine having a rotor for a rotating electric machine according to an embodiment of the present invention. As shown in Fig. 1, a rotating electric machine 100 includes a rotor 1 that rotates about the axis CL0, and a stator 2 that is arranged to surround an outer peripheral surface 1a of the rotor 1. Hereinafter, a direction parallel to the axis CL0 is defined as an axial direction, a direction extending radially from the axis CL0 as a radial direction, and a direction along a circle centered on the axis CL0 as a circumferential direction.

[0010] Fig. 2 is a cross-sectional view of the rotor 1 taken along line II-II (d-axis) in Fig. 1. As shown in Figs. 1 and 2, the rotor 1 has a rotor core 10 having a substantially annular shape centered on an axis CL0, a plurality of magnetic pole portions 30 formed in the circumferential direction on the rotor core 10, and a pair of covers 40 fixed to both axial ends of the rotor core 10. In Fig. 1, the portions of the rotor core 10 covered by the covers 40 are indicated by dotted lines.

[0011] A rotor shaft 101 that constitutes the output shaft of the rotary electric machine 100 is fitted onto an inner peripheral surface 10a of the rotor core 10. The rotor shaft 101 has a generally cylindrical shape centered on an axis CL0, and the rotor 1 and the rotor shaft 101 rotate together. An outer peripheral surface 1a of the rotor 1 corresponds to the outer peripheral surface of the rotor core 10. The rotor core 10 is formed by stacking multiple electromagnetic steel plates, which are made of a magnetic metal, in the axial direction.

[0012] As shown in Fig. 1, multiple magnetic pole portions 30 are provided at equal intervals in the circumferential direction. In the example of Fig. 1, six magnetic pole portions 30 are provided every 60°. Each magnetic pole portion 30 has multiple (six in the figure) magnet accommodating holes 31 formed in the rotor core 10 and permanent magnets 32 accommodated in the magnet accommodating holes 31. Each magnet accommodating hole 31 can accommodate one or multiple permanent magnets 32. The axis extending radially through the circumferential center of the magnetic pole portion 30 is the d-axis.

[0013] The stator 2 has a substantially annular stator core 20 centered on an axis CL0 and disposed at a predetermined radial distance from the outer peripheral surface 1a of the rotor 1, and coils 21 attached to the stator core 20. The stator core 20 is formed by laminating multiple magnetic steel sheets made of metal. When a current is applied to the coils 21, a magnetic field is generated in the stator 2. This magnetic field interacts with the magnetic field generated by the permanent magnets 32 of the magnetic pole portions 30 of the rotor 1, causing the rotor 1 to rotate.

[0014] FIG. 3 is an enlarged view of a main portion of FIG. 1, illustrating the configuration of a single magnetic pole portion 30. In FIG. 3, the axial end faces 32a, 32b of the permanent magnet 32 ​​exposed to the outside of the cover 40 are shown hatched for convenience. As shown in FIG. 3, the six magnet accommodating holes 31 in the magnetic pole portion 30 are provided symmetrically with respect to the d-axis. More specifically, the magnet accommodating holes 31 include three inner diameter side magnet accommodating holes 311 provided on the radially inner side and three outer diameter side magnet accommodating holes 312 provided on the radially outer side. The inner diameter side magnet accommodating holes 311 and the outer diameter side magnet accommodating holes 312 each extend from one axial end face to the other axial end face of the rotor core 10, and the entire rotor core 10 has a substantially rectangular parallelepiped shape.

[0015] The inner diameter side magnet accommodating hole 311 includes a central accommodating hole 311A ​​extending circumferentially so as to be substantially perpendicular to the d-axis, and a pair of outer accommodating holes 311B, 311C provided on both circumferential sides of the central accommodating hole 311A. The outer diameter side magnet accommodating hole 312 includes a central accommodating hole 312A extending circumferentially so as to be substantially perpendicular to the d-axis, and a pair of outer accommodating holes 312B, 312C provided on both circumferential sides of the central accommodating hole 312A. The outer accommodating holes 311B, 311C and 312B, 312C each extend obliquely radially outward as they move away from the d-axis, and are formed into a substantially V-shape centered on the d-axis. The central accommodating hole 312A is disposed radially outward from the central accommodating hole 311A, and the outer accommodating holes 312B, 312C are disposed radially outward from the outer accommodating holes 311B, 311C.

[0016] The permanent magnets 32 include three inner diameter side permanent magnets 321 respectively housed in the three inner diameter side magnet accommodating holes 311 and three outer diameter side permanent magnets 322 respectively housed in the three outer diameter side magnet accommodating holes 312. The inner diameter side permanent magnets 321 and the outer diameter side permanent magnets 322 are formed in the shape of flat plates extending in the axial direction and have a substantially rectangular cross section when viewed from the axial direction, corresponding to the shapes of the inner diameter side magnet accommodating holes 311 and the outer diameter side magnet accommodating holes 312, respectively. Various types of permanent magnets 32 can be used, such as neodymium magnets and ferrite magnets. The permanent magnets 32 are fixed to the rotor core 10 with an adhesive.

[0017] In a cross section perpendicular to the axis CL0, the longitudinal direction of the permanent magnet 32 ​​is referred to as the width or width direction, and the lateral direction is referred to as the thickness or thickness direction. In the rotor core 10, flux barriers 33 are formed adjacent to a pair of widthwise end faces of the permanent magnet 32, continuing to each magnet accommodating hole 31 (inner diameter side magnet accommodating hole 311, outer diameter side magnet accommodating hole 312). The flux barriers 33 are air spaces and have a higher magnetic resistance than the rotor core 10. Providing the flux barriers 33 can prevent magnetic short-circuiting of the magnetic flux generated by the permanent magnet 32 ​​on the rotor side. The flux barriers 33 can also be filled with a resin having a lower magnetic permeability than the rotor core 10, making the flux barriers 33 a resin layer.

[0018] The configuration of the cover 40 will be described. In the following, in Fig. 2, the rotor core 10 side relative to the cover 40 may be referred to as the axially inner side, and the opposite side of the rotor core 10 may be referred to as the axially outer side. Fig. 4 is a perspective view of the cover 40 arranged at one axial end side, as viewed from the axially inner side. The configurations of the covers 40 at one axial end side and the other axial end side are the same.

[0019] 2 and 4, the cover 40 has a plate portion 41 extending radially and a ring portion 42 that extends axially inward from the outer circumferential surface of the plate portion 41 and has a substantially cylindrical shape centered on the axis CL0. The cover 40 is made of a non-magnetic material such as aluminum. The cover 40 has an inner end face 401 on the inner side in the axial direction and an outer end face 402 on the outer side in the axial direction. The outer end face 402 is configured as a flat surface over the entire radial extent. The inner end face 401 includes an inner end face 411 of the plate portion 41 and an inner end face 421 of the ring portion 42. The inner end face 411 and the outer end face 402 of the plate portion 41 extend substantially parallel to each other in a direction perpendicular to the axis CL0, and the plate portion 41 is configured to have a constant thickness.

[0020] As shown in FIG. 2, the outer peripheral surface 42a of the ring portion 42 is located on a plane extending from the outer peripheral surface of the rotor core 10 (the outer peripheral surface 1a of the rotor 1). The inner end surface 421 of the ring portion 42 abuts against the axial end surface 11 of the rotor core 10. The rotor shaft 101 has a small diameter portion 102 and a large diameter portion 103. The diameters of the inner peripheral surfaces of the small diameter portion 102 and the large diameter portion 103 are equal to each other. The diameter of the outer peripheral surface of the large diameter portion 103 is larger than the diameter of the outer peripheral surface of the small diameter portion 102.

[0021] The diameter of the inner peripheral surface 413 of the plate portion 41 and the diameter of the outer peripheral surface of the small diameter portion 102 are equal or approximately equal. The inner peripheral surface 413 of the plate portion 41 is fitted into the outer peripheral surface of the small diameter portion 102 by press fitting, and the outer end surface 402 of the plate portion 41 abuts against the axially inner end surface of the large diameter portion 103. As a result, the cover 40 is fixed to the rotor core 10 via the rotor shaft 101, and the cover 40 rotates integrally with the rotor core 10.

[0022] By disposing the cover 40 having the plate portion 41 and the ring portion 42 adjacent to the axial end surface 11 of the rotor core 10 in this manner, a flow space SP1 through which a coolant flows can be formed between the rotor core 10 and the cover 40. The rotor shaft 101 has a plurality of through holes 101a that penetrate the rotor shaft 101 in the radial direction, facing the flow space SP1. This allows the coolant to be guided from the radially inner side of the rotor shaft 101 through the through holes 101a into the flow space SP1. Cooling oil, for example, is used as the coolant.

[0023] 4, a plurality of substantially rectangular through holes 43 are formed in the plate portion 41 in correspondence with the installation positions of the permanent magnets 32. More specifically, the plate portion 41 is divided into six areas AR1 centered on the axis CL0 in correspondence with the magnetic pole portions 30. Three through holes 43 (inner diameter side through holes 431) corresponding to the inner diameter side permanent magnets 321 and three through holes 43 (outer diameter side through holes 432) corresponding to the outer diameter side permanent magnets 322 are formed in each area AR1.

[0024] As shown in FIG. 3 , the inner diameter side through hole 431 is larger than the axial end face 32a of the inner diameter side permanent magnet 321. That is, the edges of the inner diameter side through hole 431 are located outside both width direction end faces of the inner diameter side permanent magnet 321, and the edges of the inner diameter side through hole 431 are located outside both thickness direction end faces of the inner diameter side permanent magnet 321. Therefore, the entire axial end face 32a of the inner diameter side permanent magnet 321 is exposed from the cover 40 when viewed from the axial direction. Similarly, the outer diameter side through hole 432 is larger than the axial end face 32b of the outer diameter side permanent magnet 322. That is, the edges of the outer diameter side through hole 432 are located outside both width direction end faces of the outer diameter side permanent magnet 322, and the edges of the outer diameter side through hole 432 are located outside both thickness direction end faces of the outer diameter side permanent magnet 322. Therefore, the entire axial end face 32b of the outer diameter side permanent magnet 322 is exposed from the cover 40 when viewed from the axial direction.

[0025] 2, both axial ends of the inner diameter side permanent magnet 321 and both axial ends of the outer diameter side permanent magnet 322 protrude axially outward from the axially opposite end faces 11 of the rotor core 10 by the same length L1. Length L1 is longer than length L2 from the axial end face 11 of the rotor core 10 to the inner end face 411 of the plate portion 41, and shorter than length L3 from the axial end face 11 of the rotor core 10 to the outer end face 402 of the plate portion 41. Therefore, axial end faces 32a, 32b of the permanent magnets 32 (inner diameter side permanent magnet 321, outer diameter side permanent magnet 322) are located inside the through holes 431, 432.

[0026] 4, a plurality of circumferential protrusions 45 that protrude radially inward are provided on the inner end surface 411 of the plate portion 41 at the boundaries between a plurality of circumferential regions AR1. The protrusions 45 extend radially outward from the inner circumferential surface 413 of the plate portion 41, and via the protrusions 45, the inner diameter side of the flow space SP1 (FIG. 2) between the rotor core 10 and the cover 40 is divided into a plurality of spaces corresponding to the magnetic pole portions 30.

[0027] The rotor 1 for a rotating electric machine according to this embodiment is assembled, for example, in the following procedure: First, the plate portion 41 of the cover 40 on one axial side is press-fitted onto the small diameter portion 102 of the rotor shaft 101. At this time, the cover 40 is pushed in the axial direction until the outer end surface 402 of the plate portion 41 abuts against the axially inner end surface of the large diameter portion 103.

[0028] Next, the rotor core 10, to which the permanent magnets 32 have been fixed in advance, is fitted onto the small diameter portion 102 of the rotor shaft 101. At this time, while aligning the positions of the permanent magnets 32 with the positions of the through holes 431, 432, the rotor core 10 is pushed in the axial direction until the axial end face 11 of the rotor core 10 abuts against the inner end face 421 of the ring portion 42 of the cover 40.

[0029] Next, the plate portion 41 of the cover 40 on the other axial side is press-fitted onto the small diameter portion 102 of the rotor shaft 101. At this time, while aligning the positions of the through holes 431, 432 with the positions of the permanent magnets 32, the cover 40 is pushed in the axial direction until the inner end surface 421 of the ring portion 42 of the cover 40 abuts against the axial end surface 11 of the rotor core 10. This completes the assembly of the rotor 1.

[0030] The main operation of the rotor 1 for a rotating electric machine according to this embodiment will now be described. FIG. 5 is a diagram schematically illustrating the flow of a cooling medium around the rotor 1. As shown in FIG. 5, cooling oil discharged from an oil pump (not shown) is supplied to the inside of the rotor shaft 101. This cooling oil flows into the flow space SP1 through the through hole 101a of the rotor shaft 101, as indicated by the arrows in FIG. 5. Furthermore, the cooling oil in the flow space SP1 flows radially outward due to centrifugal force, as indicated by the arrows in FIG. 5, and flows out to the outside of the cover 40 through the through holes 431 and 432 in the cover 40.

[0031] At this time, the cooling oil flows along the surfaces of the axial end portions of the permanent magnets 321, 322. That is, not only does the cooling oil flow along the axial end faces 32a, 32b of the permanent magnets 321, 322, but the cooling oil also flows along the side surfaces axially inward of the end faces 32a, 32b. This increases the area (wetted area) with which the cooling oil comes into contact at the axial end portions of the permanent magnets 321, 322, thereby enabling efficient cooling of the permanent magnets 321, 322. In addition, because the cooling oil flows out to the outside of the cover 40 through the through holes 431, 432, the amount of cooling oil flowing into the air gap through the gap between the rotor core 10 and the cover 40 can be reduced.

[0032] The cooling oil that has flowed out of the cover 40 accumulates below the rotating electrical machine 100. This cooling oil is sucked by the oil pump through a strainer, and after being cooled in the oil cooler, is supplied back into the rotor shaft 101.

[0033] 6 and 7 are diagrams showing modifications of Figures 2 and 3, respectively. In this modification, the entire axial end faces 32a and 32b of the permanent magnet 32 ​​are not exposed from the cover 40, but only portions of the axial end faces 32a and 32b are covered by the cover 40. That is, as shown in Figures 6 and 7, a substantially rectangular overlapping plate portion 46 is provided on the plate portion 41 so as to cover portions (for example, outer diameter side edges) of the through holes 431 and 432.

[0034] The outer end face of the overlapping plate portion 46 is located on the same plane as the outer end face 402 of the plate portion 41. The inner end face of the overlapping plate portion 46 is located axially outward of the inner end face 411 of the plate portion 41 and also axially outward of the axial end faces 32a, 32b of the permanent magnet 32. By providing the overlapping plate portion 46, the area of ​​the exposed portions (hatched) of the axial end faces 32a, 32b of the permanent magnet 32 ​​is smaller than that shown in FIG. 3. In other words, the openings of the through holes 431, 432 on the outer end face 402 side are smaller than the openings on the inner end face 411 side.

[0035] In this way, by providing the overlapping plate portion 46 on the plate portion 41 of the cover 40 so as to cover a portion of the axial end faces 32a, 32b of the permanent magnet 32, it is possible to prevent the permanent magnet 32 ​​from moving in the axial direction and to function as a retainer for the permanent magnet 32. Furthermore, since the protruding length L1 of the permanent magnet 32 ​​is longer than the length L2 of the flow space SP1 between the axial end face 11 of the rotor core 10 and the inner end face 411 of the cover 40, the axial end of the permanent magnet 32 ​​is located inside the through holes 431, 432. Therefore, the axial end of the permanent magnet 32 ​​can be efficiently cooled by the cooling oil passing through the through holes 431, 432.

[0036] Considering the flow of cooling oil in the flow space SP1, the axial end surfaces of the permanent magnets 32 (e.g., inner diameter side permanent magnets 321) may be formed with an uneven shape. FIG. 8 is a perspective view of the axial end portion of the inner diameter side permanent magnet 321, showing an example of such an arrangement. As shown in FIG. 8, a recess 325 is provided in the widthwise center of the axial end surface 32a of the inner diameter side permanent magnet 321. The depth d of the recess 325 is equal to the protruding length L1 (FIGS. 2 and 6) of the permanent magnet 32 ​​from the axial end surface 11 of the rotor core 10. Note that the depth d may be shorter or longer than the length L1.

[0037] FIG. 9 is a front view of the rotor core 10 including the inner diameter side permanent magnets 321 of FIG. 8. Although not shown, a cover 40 similar to that of FIG. 2 or 6 is provided at the axial end of the rotor core 10. As shown in FIG. 9, each of the three inner diameter side permanent magnets 321 has a recess 325 formed in its widthwise center along the thickness direction (short direction) of the inner diameter side permanent magnet 321, i.e., along the radial direction. Note that the radial direction in this case includes a direction from the inner diameter side to the outer diameter side passing through the axis CL0, and a direction from the inner diameter side to the outer diameter side without passing through the axis CL0. With this configuration, as shown by the arrows in FIG. 9, the coolant flowing radially outward due to centrifugal force passes through the recess 325 and flows toward the outer diameter side permanent magnets 322.

[0038] This allows the cooling oil that has flowed into the flow space SP1 from the inside of the rotor shaft 101 to be easily guided to the outer diameter side permanent magnets 322. As a result, the outer diameter side permanent magnets 322 can be cooled efficiently. Note that instead of providing the recesses 325 on all three inner diameter side permanent magnets 321, a recess 325 may be provided only on the inner diameter side permanent magnet 321 at the circumferential center, for example. Instead of providing a single recess 325 at the center in the width direction of the inner diameter side permanent magnet 321, a plurality of recesses 325 may be provided along the width direction.

[0039] Fig. 10 is a diagram showing a modified example of Fig. 9, and Fig. 11 is a perspective view of the rotor 1 of Fig. 10. In the example of Figs. 10 and 11, recesses 325 are provided in the axial end face 32a of the inner diameter side permanent magnet 321 and the axial end face 32b of the outer diameter side permanent magnet 322. More specifically, a plurality of recesses 325 are provided in each of the end faces 32a, 32b, and a protrusion 326 is provided between each pair of recesses 325, 325. In other words, the recesses 325 and the protrusions 326 are provided alternately in the width direction of the permanent magnet 32.

[0040] The number of recesses 325 provided on the end face 32a of the inner diameter side permanent magnet 321 is different from the number of recesses 325 provided on the end face 32b of the outer diameter side permanent magnet 322. Specifically, the number of recesses 325 on the end face 32a is an even number (four in the figure), and the number of recesses 325 on the end face 32b is an odd number (three in the figure). Note that the number of recesses 325 on the end face 32a may be odd, and the number of recesses 325 on the end face 32b may be even.

[0041] Providing multiple recesses 325 in the permanent magnet 32 ​​in this manner increases the wetted area at the axial end of the permanent magnet 32, allowing for efficient cooling of the permanent magnet 32. Furthermore, while an even number of inner diameter side permanent magnets 321 are provided, an odd number of outer diameter side permanent magnets 322 are provided, and therefore the convex portions 326 of the outer diameter side permanent magnets 322 are disposed radially outward of the concave portions 325 of the inner diameter side permanent magnets 321. For this reason, the cooling oil that has passed through the concave portions 325 of the inner diameter side permanent magnet 321 is more likely to hit the convex portions 326 of the outer diameter side permanent magnets 322, allowing for efficient cooling of the outer diameter side permanent magnets 322.

[0042] According to this embodiment, the following effects can be achieved. (1) A rotor 1 for a rotating electric machine includes a rotor core 10 having a substantially cylindrical shape centered on an axis CL0 and having magnet accommodating holes 31 extending in the axial direction, permanent magnets 32 accommodated in the magnet accommodating holes 31, and a cover 40 integrally provided with the rotor core 10 and facing the axial end face 11 of the rotor core 10 so as to form a flow path (flow space SP1) through which cooling oil flows between the cover 40 and the axial end face 11 of the rotor core 10 (FIGS. 1 to 3). The cover 40 has an inner end face 401 on the inner side in the axial direction and an outer end face 402 on the outer side in the axial direction (FIG. 2). The inner end face 401 includes an inner end face 421 of a ring portion 42 that abuts against the axial end face 11 of the rotor core 10, and an inner end face 411 of a plate portion 41 that is spaced axially from the axial end face 11 of the rotor core 10 (FIG. 2). The cover 40 has through holes 431, 432 extending from the inner end surface 411 of the plate portion 41 to the outer end surface 402 (FIGS. 2 and 4). The axial ends of the permanent magnets 32 protrude axially outward from the axial end surface 11 of the rotor core 10, and the axial end surfaces 32a, 32b of the permanent magnets 32 are located axially outward of the inner end surface 411 of the plate portion 41 (FIG. 2).

[0043] This configuration allows the cooling oil to flow along the axial ends of the permanent magnets 32, increasing the wetted area of ​​the surface of the permanent magnets 32 that comes into contact with the cooling oil. This increases the cooling efficiency of the permanent magnets 32, allowing the permanent magnets 32 to be sufficiently cooled.

[0044] (2) The axial end faces 32a and 32b of the permanent magnet 32 ​​are located inside the through holes 431 and 432 (FIG. 2). This allows the surface of the permanent magnet 32 ​​to be efficiently cooled by the cooling oil flowing through the through holes 4321 and 432.

[0045] (3) The cover 40 is formed so as to cover a portion of the axial end faces 32a, 32b of the permanent magnet 32 ​​(FIG. 6). This prevents the permanent magnet 32 ​​from moving in the axial direction, and prevents the permanent magnet 32 ​​from falling off the rotor core 10.

[0046] (4) The magnet accommodating hole 31 includes an inner diameter side magnet accommodating hole 311 and an outer diameter side magnet accommodating hole 312 disposed radially outward of the inner diameter side magnet accommodating hole 311 about the axis CL0 ( FIG. 3 ). The permanent magnets 32 include an inner diameter side permanent magnet 321 accommodated in the inner diameter side magnet accommodating hole 311 and an outer diameter side permanent magnet 322 accommodated in the outer diameter side magnet accommodating hole 312 ( FIG. 3 ). The inner diameter side permanent magnet 321 has a recess 325 formed in a radially concave shape on its axial end face 32a ( FIG. 9 ). This allows cooling oil flowing radially outward due to centrifugal force to easily pass through the inner diameter side permanent magnet 321 and be guided to the outer diameter side permanent magnet 322. As a result, a sufficient amount of cooling oil can flow along the surface of the outer diameter side permanent magnet 322 located downstream of the flow path defined by the flow space SP1, thereby efficiently cooling all of the multiple permanent magnets 32.

[0047] (5) The outer diameter side permanent magnet 322 has alternating recesses 325 and protrusions 326 on its axial end surface 32b (FIG. 10). The protrusions 326 of the outer diameter side permanent magnet 322 are provided radially outward of the recesses 325 of the inner diameter side permanent magnet 321 (FIG. 10). By having the outer diameter side permanent magnet 322 alternately have the recesses 325 and protrusions 326 in this way, the wetted area of ​​the axial end of the outer diameter side permanent magnet 322 is increased, improving the cooling effect. In addition, the cooling oil that passes through the recesses 325 of the inner diameter side permanent magnet 321 and flows radially outward is likely to come into contact with the protrusions 326 of the outer diameter side permanent magnet 322, thereby allowing the outer diameter side permanent magnet 322 to be efficiently cooled.

[0048] This embodiment can be modified in various ways. Several modifications will be described below. In the above embodiment, the rotor core 10 is provided with a plurality of inner diameter side magnet accommodating holes 311 (first magnet accommodating holes) that accommodate inner diameter side permanent magnets 321 (first magnets) and a plurality of outer diameter side magnet accommodating holes 312 (second magnet accommodating holes) that accommodate outer diameter side permanent magnets 322 (second magnets). However, the number, arrangement, shape, etc. of the magnet accommodating holes are not limited to those described above. Therefore, the configuration of the rotor core is also not limited to those described above. Either the first magnet accommodating holes or the second magnet accommodating holes may be provided as the magnet accommodating holes, and either the first magnet or the second magnet may be provided as the magnet to be accommodated in the magnet accommodating holes.

[0049] In the above embodiment, the cooling oil flowing in from inside the rotor shaft 101 flows through the flow space SP1 between the axial end face 11 of the rotor core 10 and the cover 40, and then flows out from the through holes 431, 432 of the cover 40, but the configuration of the cover 40 as a flow path forming member is not limited to that described above as long as it is disposed opposite the axial end face 11 of the rotor core 10 so as to form a flow path through which the coolant flows between it and the axial end face 11 of the rotor core 10. In the above embodiment, the cover 40 as a flow path forming member is provided at both axial ends of the rotor core 10, but it may also be provided at one axial end.

[0050] In the above embodiment, the inner end surface 401 of the cover 40 has the inner end surface 421 (first end surface) of the ring portion 42 that abuts against the axial end surface 11 of the rotor core 10, and the inner end surface 411 (second end surface) of the plate portion 41 that is spaced apart from the axial end surface 11 of the rotor core 10, but the configuration of the first end surface and the second end surface is not limited to that described above. In the above embodiment, the axial end surfaces 32a, 32b of the permanent magnet 32 ​​are positioned inside the through holes 431, 432 of the cover 40, but the positions of the axial end surfaces 32a, 32b are not limited to that described above as long as they are positioned axially outward of the inner end surface 411 of the plate portion 41.

[0051] In the above embodiment (FIG. 6), the plate portion 41 of the cover 40 is provided with the overlapping plate portion 46 so as to cover a portion of the axial end faces 32a, 32b of the permanent magnet 32, but other configurations may be used to cover a portion of the axial end faces 32a, 32b. In the above embodiment, cooling oil is used as the cooling medium, but other cooling media may also be used.

[0052] The above description is merely an example, and the present invention is not limited to the above-described embodiment and modifications as long as the features of the present invention are not impaired. One or more of the above-described embodiment and modifications can be arbitrarily combined, and modifications can also be combined with each other. [Explanation of symbols]

[0053] 1 rotor, 10 rotor core, 11 axial end face, 31 magnet accommodating hole, 32 permanent magnet, 32a, 32b axial end face, 40 cover, 41 plate portion, 46 overlapping portion, 311 inner diameter side magnet accommodating hole, 312 outer diameter side magnet accommodating hole, 321 inner diameter side permanent magnet, 322 outer diameter side permanent magnet, 325 recess, 326 protrusion, 401 inner end face, 402 outer end face, 411 inner end face, 421 axial end face, 431, 432 through hole, CL0 axis

Claims

1. a rotor core that is generally cylindrical and has a magnet accommodating hole extending in the axial direction; a magnet accommodated in the magnet accommodating hole; a flow path forming member disposed opposite the axial end surface of the rotor core so as to form a flow path through which a cooling medium flows between the axial end surface and the flow path forming member, the flow path forming member has an inner end surface on the inner side in the axial direction and an outer end surface on the outer side in the axial direction, the inner end surface has a first end surface abutting the axial end surface of the rotor core and a second end surface spaced apart from the axial end surface of the rotor core, a through hole is provided in the flow path forming member from the second end surface to the outer end surface, a rotor for a rotating electric machine, characterized in that an axial end of the magnet protrudes axially outward from the axial end face of the rotor core, and the axial end face of the magnet is located axially outward from the second end face.

2. 2. The rotor for a rotating electric machine according to claim 1, The rotor for a rotating electric machine, wherein the axial end face of the magnet is located inside the through hole.

3. 3. The rotor for a rotating electric machine according to claim 2, The rotor for a rotating electric machine is characterized in that the flow path forming member is formed so as to cover a part of the axial end face of the magnet.

4. 4. The rotor for a rotating electric machine according to claim 1, the magnet accommodating hole includes a first magnet accommodating hole and a second magnet accommodating hole provided radially outward from the first magnet accommodating hole about the axis, The magnet includes a first magnet accommodated in the first magnet accommodating hole and a second magnet accommodated in the second magnet accommodating hole, The rotor for a rotating electric machine is characterized in that the first magnet has a recess formed in an axial end face thereof in a radially recessed shape.

5. 5. The rotor for a rotating electric machine according to claim 4, A rotor for a rotating electric machine, characterized in that the second magnet has alternating concave and convex portions on its axial end surface, and the convex portions of the second magnet are located radially outside the concave portions of the first magnet.

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