Permanent magnet rotating electric machine

Abstract

In magnet insertion holes (11, 21) formed in first and second rotor cores (10, 20), flux barriers (12, 22) for preventing magnetic flux leakage are formed at both ends in the width direction of each permanent magnet (50), and the distance formed between surfaces facing in the thickness direction of the permanent magnet (50) is set to be larger than the thickness of the permanent magnet (50), whereby gaps (17, 27) are formed between the permanent magnet (50) and the magnet insertion holes (11, 21). The magnet insertion hole (11) of the first rotor core (10) has formed therein a guide part (13) for positioning the permanent magnet (50) in the width direction at at least one end side in the width direction of the permanent magnet (50). The magnet insertion hole (21) of the second rotor core (20) has formed therein an opening (29) that connects the gap (27) and the flux barrier (22) to each other. The first rotor core (10) and the second rotor core (20) are laminated together in a mixed manner in the axis direction.

Description

[Technical Field]

[0001] The present application relates to a permanent magnet rotating electric machine. [Background technology]

[0002] A rotor structure for a permanent magnet type rotating electric machine is disclosed that includes a first rotor core in which permanent magnet insertion holes are formed and which is provided with guide portions for regulating the position of the permanent magnets in the permanent magnet insertion holes, and a second rotor core in which no guide portions are formed and only permanent magnet insertion holes are formed; these first and second rotor cores are combined and stacked in the axial direction in multiple layers, and permanent magnets are pressed into each permanent magnet insertion hole, passing through the axial direction, thereby holding the magnets and suppressing demagnetization of the permanent magnets due to magnetic flux flowing through the permanent magnets by the guide portions (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-1933 Summary of the Invention [Problem to be solved by the invention]

[0004] In the rotors of conventional permanent magnet rotating electric machines, there is no gap between the permanent magnet insertion holes in the rotor core and the permanent magnets, and the permanent magnets are press-fit into the magnet insertion holes to form the rotor, which can lead to damage such as cracking and chipping of the permanent magnets. Furthermore, if the permanent magnets are coated with an anti-rust coating, the coating can peel off, causing the permanent magnets to rust. Furthermore, there are issues such as the permanent magnets not being able to be smoothly inserted into the permanent magnet insertion holes. Furthermore, press-fitting the permanent magnets into the rotor core applies stress to the rotor core, which can lead to damage to the rotor core. Furthermore, in a configuration in which the magnet insertion holes and magnets have a V-shape that protrudes radially inward, when centrifugal force is generated from the permanent magnets as the rotor rotates, there is a problem in that the number of rotor cores with guide portions for holding the magnets on the outer diameter side is small, so the stress applied to the guide portions formed in the permanent magnet insertion holes is high, which could cause damage to the rotor core.

[0005] The present application discloses technology for solving the above-mentioned problems, and aims to provide a permanent magnet rotating electric machine that makes it easier to insert permanent magnets into magnet insertion holes in the rotor core, eliminates damage to the magnets when inserting the magnets, and improves the strength of the rotor without applying excess stress to the rotor core when inserting the magnets. [Means for solving the problem]

[0006] The permanent magnet type rotating electric machine disclosed in the present application comprises a stator and a rotor rotatably supported by a rotating shaft inside the stator, the rotor having a rotor core formed by stacking a plurality of electromagnetic steel plates in the axial direction, a plurality of magnet insertion holes formed in the rotor core, and strip-shaped permanent magnets attached so as to pass through the magnet insertion holes in the axial direction, The rotor core has a first rotor core and a second rotor core, and the magnet insertion holes formed in the first rotor core and the second rotor core are provided with flux barriers on both sides of the permanent magnet in the width direction to prevent leakage of magnetic flux, and facing in the thickness direction of the permanent magnet. face to face a gap is formed between the permanent magnet and the magnet insertion hole by setting the distance between the permanent magnet and the magnet insertion hole to be larger than the thickness of the permanent magnet, The magnet insertion hole of the first rotor core is formed with a guide portion for positioning the permanent magnet in the width direction on at least one end side of the permanent magnet in the width direction, and an opening communicating the gap with the flux barrier is formed in the magnet insertion hole of the second rotor core, The first rotor cores and the second rotor cores are stacked in a mixed manner in the axial direction. [Effects of the Invention]

[0007] According to the permanent magnet rotating electric machine disclosed in the present application, permanent magnets can be easily inserted into the magnet insertion holes of the rotor core, preventing damage to the magnets when inserting them, and improving the strength of the rotor without applying extra stress to the rotor core when inserting the magnets. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view perpendicular to the rotation axis of a permanent magnet type rotating electric machine according to a first embodiment. [Figure 2] 2 is an enlarged cross-sectional view of one magnetic pole of a first rotor core that constitutes the permanent magnet type rotating electric machine according to the first embodiment. FIG. [Figure 3] 4 is an enlarged cross-sectional view of one magnetic pole of a second rotor core that constitutes the permanent magnet type rotating electric machine according to the first embodiment. FIG. [Figure 4] 2 is an enlarged cross-sectional view of one magnetic pole in which a permanent magnet is attached to a first rotor core that constitutes the permanent magnet type rotating electric machine according to the first embodiment. FIG. [Figure 5] 4 is an enlarged cross-sectional view of one magnetic pole in which a permanent magnet is attached to a second rotor core that constitutes the permanent magnet type rotating electric machine according to the first embodiment. FIG. [Figure 6] 3 is an enlarged cross-sectional view showing a state in which a permanent magnet is attached to one magnet insertion hole of a first rotor core that constitutes the permanent magnet type rotating electric machine according to the first embodiment. FIG. [Figure 7] 4 is an enlarged cross-sectional view showing a state in which a permanent magnet is attached to one magnet insertion hole of a second rotor core that constitutes the permanent magnet type rotating electric machine according to the first embodiment. FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along line AA in FIGS. 6 and 7. [Figure 9] 4 is an enlarged cross-sectional view showing a flow when resin is injected into a second rotor core that constitutes the permanent magnet type rotating electric machine according to the first embodiment. FIG. [Figure 10] 10 is an enlarged cross-sectional view showing a modified example of the second rotor core according to the first embodiment, showing a state in which a permanent magnet is attached to one magnet insertion hole. FIG. [Figure 11] 10 is an enlarged cross-sectional view showing another modified example of the second rotor core according to the first embodiment, showing a state in which a permanent magnet is attached to each magnet insertion hole. FIG. [Figure 12] 10 is an enlarged cross-sectional view of one magnetic pole in which a permanent magnet is attached to a first rotor core that constitutes a permanent magnet type rotating electric machine according to a second embodiment. FIG. [Figure 13] 10 is an enlarged cross-sectional view of one magnetic pole in which a permanent magnet is attached to a second rotor core that constitutes a permanent magnet type rotating electric machine according to a second embodiment. FIG. [Figure 14] FIG. 14 is a cross-sectional view taken along line BB in FIGS. 12 and 13. [Figure 15] 10 is an enlarged cross-sectional view showing the flow of fluid relative to a second rotor core that constitutes a permanent magnet type rotating electric machine according to a second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 Fig. 1 is a cross-sectional view perpendicular to the rotation axis of a permanent magnet type rotating electric machine according to embodiment 1, Fig. 2 is an enlarged cross-sectional view of one magnetic pole of a first rotor core constituting the permanent magnet type rotating electric machine according to embodiment 1, Fig. 3 is an enlarged cross-sectional view of one magnetic pole of a second rotor core constituting the permanent magnet type rotating electric machine according to embodiment 1, Fig. 4 is an enlarged cross-sectional view of one magnetic pole with a permanent magnet attached to a first rotor core constituting the permanent magnet type rotating electric machine according to embodiment 1, Fig. 5 is an enlarged cross-sectional view of one magnetic pole with a permanent magnet attached to a second rotor core constituting the permanent magnet type rotating electric machine according to embodiment 1. In addition, Fig. 6 is an enlarged cross-sectional view showing a state in which a permanent magnet is attached to one magnet insertion hole of the first rotor core, Fig. 7 is an enlarged cross-sectional view showing a state in which a permanent magnet is attached to one magnet insertion hole of the second rotor core, and Fig. 8 is a cross-sectional view taken along line A-A in Figs. 6 and 7.

[0010] As shown in FIG. 1, the permanent magnet rotating electric machine according to the first embodiment of the present invention has a stator 1 provided on the outer periphery, and a rotor 5 rotatably supported by a rotating shaft inside the stator 1.

[0011] The stator 1 is composed of a stator core 2 and a coil 3 wound around the stator core 2.

[0012] On the other hand, the rotor 5 comprises a rotor core 8 and a permanent magnet 50, and in this embodiment 1, the rotor core 8 has a first rotor core 10 and a second rotor core 20, both made of electromagnetic steel plates, and the first rotor core 10 and the second rotor core 20 are stacked in multiple pieces in the axial direction of the rotor 5, as described below.

[0013] As shown in FIGS. 2 to 5, the first rotor core 10 and the second rotor core 20 each have magnet insertion holes 11, 21 of the same polarity formed in a V-shape that protrudes radially inward when viewed from the outer periphery of the rotor 5. That is, each magnet insertion hole 11, 21 is formed in a V-shape so that the circumferential distance between the six magnet insertion holes 11, 21 arranged for one pole gradually increases toward the outer periphery of the rotor, and a pair of magnet insertion holes 11, 21 is formed with a three-layer structure in the radial direction, penetrating the axial direction. A permanent magnet 50 is fitted in each magnet insertion hole 11, 21, thereby constituting one magnetic pole of the rotating electric machine. Furthermore, the permanent magnets 50 forming two adjacent magnetic poles are arranged so that their north and south poles are reversed relative to each other.

[0014] The permanent magnet 50 has a rectangular strip-like shape in plan view in cross section perpendicular to the axial direction of the rotor 5, and as shown in Fig. 8, in order to reduce loss of the permanent magnet 50, it is divided into a predetermined number of parts in the axial direction and arranged in each of the magnet insertion holes 11, 21 of the first rotor core 10 and the second rotor core 20. That is, in this first embodiment, with respect to the axial center of one divided permanent magnet 50, the first rotor core 10 is arranged at both ends of it, and the second rotor core 20 is arranged between the first rotor cores 10.

[0015] In this way, at least one first rotor core 10 is arranged in a range corresponding to the axial length of the divided permanent magnet 50, and the first rotor core 10 and the second rotor core 20 are stacked in a mixed state in the axial direction to form the rotor core 8.

[0016] Focusing on the individual magnet insertion holes 11, 21 of the first rotor core 10 and the second rotor core 20, each magnet insertion hole 11, 21 is provided with flux barriers 12, 22 on both sides of the width of the permanent magnet 50 to prevent leakage of magnetic flux.

[0017] Furthermore, the magnet insertion holes 11, 21 of the first rotor core 10 and the second rotor core 20 are configured so that the distance between the opposing surfaces of the magnet insertion holes 11, 21 in the thickness direction (short side direction) of the permanent magnet 50 is greater than the thickness of the permanent magnet 50. As a result, gaps 17, 27 are formed between the radially inner inner surfaces 15, 25 on the long side of the magnet insertion holes 11, 21 and the opposing radially inner surfaces on the long side of the permanent magnet 50. In this case, the gaps 17, 27 are configured to have dimensions that allow a fluid resin to flow in, as described below. For example, they are configured to be approximately several tens of μm to several hundreds of μm. At least a portion of the radially outer surfaces 16, 26 on the long side of the magnet insertion holes 11, 21 contacts the opposing radially outer surfaces on the long side of the permanent magnet 50.

[0018] In addition, in this embodiment 1, as shown in Figures 2, 4, and 6, in order to regulate the widthwise (long side) position of the permanent magnet 50 inside the magnet insertion hole 11, guide portions 13 are formed on the inner surface 15 on the radially inner side of the long side of the magnet insertion hole 11 so as to protrude into the magnet insertion hole 11 at positions facing the corners at both ends of the long side of the permanent magnet 50.

[0019] In this case, the length between the left and right guide portions 13 needs to regulate the position of the permanent magnet 50 in the long side direction, so the dimensional difference between the distance between the two guide portions 13 and the width (length of the long side) of the permanent magnet 50 is set to, for example, about several tens of μm to several hundreds of μm so as not to deteriorate the insertability of the permanent magnet 50 into the rotor core 8.

[0020] On the other hand, as shown in Figures 3, 5, and 7, for the magnet insertion hole 21 of the second rotor core 20, the radially inner surface 25 of the long side of the magnet insertion hole 21 has recesses 23 that bulge radially inward at positions opposite the corners at both ends of the long side of the permanent magnet 50, so as to straddle the corners of the permanent magnet 50.

[0021] In this way, for the magnet insertion hole 21 of the second rotor core 20, instead of providing a guide portion 13 like in the first rotor core 10, a recess 23 is provided at a position opposite the corner of the permanent magnet 50, and as shown in Figure 7, an opening 29 is formed that communicates with the flux barrier 22 from the gap 27 between the permanent magnet 50 and the magnet insertion hole 21.

[0022] By adopting the above configuration, it becomes easier to insert the permanent magnets 50 into the magnet insertion holes 11, 21 of the first and second rotor cores 10, 20, preventing damage during magnet insertion and improving the ease of inserting the permanent magnets 50, thereby improving productivity. Furthermore, no extra stress is applied to the rotor core 8, improving the strength of the rotor core 8. Furthermore, by mixing the first rotor core 10 and the second rotor core 20 in the axial direction, it becomes possible to regulate the position of each of the permanent magnets 50 divided into multiple pieces in the axial direction in the width direction (long side direction).

[0023] Furthermore, in this embodiment 1, as shown in Figures 6 to 8, the space including the flux barriers 12, 22, gaps 17, 27, and recesses 23 existing between the magnet insertion holes 11, 21 and the permanent magnet 50 is filled with resin 60, which is a non-magnetic material.

[0024] To fill the magnet insertion holes 11, 21 with resin 60, for example, after the permanent magnets 50 are inserted into the magnet insertion holes 11, 21, while the resin 60 is in a fluid state, a resin injection gate is placed at the axial end of the rotor core 8 where the flux barriers 12, 22 are provided, and the resin is injected from the core end on one axial end side of the flux barriers 12, 22. At this time, the openings of the flux barriers 12, 22 on the other axial end side are kept closed.

[0025] As a result, the resin that has flowed into the flux barriers 12, 22 initially flows primarily into the recesses 23 that form the openings 29 of the second rotor core 20, as indicated by dashed arrows FL in FIG. 9 . Then, as indicated by solid arrows PL in FIG. 9 , a force is generated that pushes the permanent magnets 50 radially outward in a direction parallel to the thickness direction (short side direction). This causes the radially outer surfaces of the long sides of the permanent magnets 50 to be pressed against the radially outer surfaces 26 of the long sides of the magnet insertion holes 21 that face them. As a result, gaps 27 are formed between the radially inner surfaces 25 of the long sides of the magnet insertion holes 21 and the radially inner surfaces of the long sides of the permanent magnets 50 that face them, and resin flows into and fills these gaps 27. Furthermore, due to the presence of the second rotor core 20, the resin that has flowed into the gaps 27 between the permanent magnets 50 and the magnet insertion holes 21 also flows out along the axial direction, filling the gaps 17 between the permanent magnets 50 of the first rotor core 10 and the magnet insertion holes 11. Thereafter, the resin hardens, and the permanent magnets 50 are fixed at predetermined positions inside the magnet insertion holes 11, 21 of the first and second rotor cores 10, 20, respectively.

[0026] In this way, in both the first and second rotor cores 10 and 20, the resin 60 fills the entire gaps 17, 27 between the radially inner surfaces of the long sides of the permanent magnets 50 and the opposing radially inner surfaces 15, 25 of the long sides of the magnet insertion holes 11, 21, thereby fixing the permanent magnets 50. This improves the strength when adhesively fixing the permanent magnets 50.

[0027] If the rotor core were to be constructed solely from the first rotor core 10 without the second rotor core 20, there would be no openings forming a path connecting the flux barrier 12 to the gaps 17, and therefore resin would not sufficiently flow into the gaps 17 between the permanent magnets 50 of the first rotor core 10 and the magnet insertion holes 11. This would result in the permanent magnets 50 being fixed with their positions in the thickness direction (short side direction) being unstable.

[0028] In contrast, when the rotor core 8 is configured to include not only the first rotor core 10 but also the second rotor core 20, as in the first embodiment, the position of the permanent magnet 50 in its thickness direction (short side direction) is stabilized. Moreover, because the radially outer surface of the long side of the permanent magnet 50 is pressed against the radially outer surface 26 of the long side of the magnet insertion hole 21 that faces it, the magnetic force of the permanent magnet 50 can be used more effectively than when the radially inner surface of the long side of the permanent magnet 50 is pressed against the radially inner surface 25 of the magnet insertion hole 21 that faces it. This makes it possible to suppress a decrease in torque of the permanent magnet type rotating electric machine.

[0029] Furthermore, by filling the gaps 17, 27 between the permanent magnet 50 and the magnet insertion holes 11, 21 with resin 60, the heat generated by the permanent magnet 50 can be transmitted to the part of the rotor core 8 that is inside the permanent magnet 50 via the resin 60, thereby making it possible to suppress the temperature rise of the permanent magnet 50.

[0030] Furthermore, in a configuration such as this embodiment 1 in which the circumferential distance between the magnet insertion holes 11, 21 is formed in a V-shape so that it increases toward the outer periphery of the rotor 5, when centrifugal force is generated on the permanent magnets 50 due to the rotation of the rotor 5, the centrifugal force is borne not only by the left and right guide portions 13 provided on the first rotor core 10, but also by the left and right flux barriers 22 of the second rotor core 20 and the resin 60 filled in the recesses 23, thereby preventing damage to the guide portions 13 of the first rotor core 10.

[0031] As described above, in the permanent magnet rotating electric machine according to the first embodiment, the rotor core 8 is formed by stacking the first rotor cores 10 and the second rotor cores 20 in a mixed state in the axial direction, and in this case, gaps 17 and 27 are formed between the permanent magnets 50 and the magnet insertion holes 11 and 21, making it easy to insert the permanent magnets 50 into the magnet insertion holes 11 and 21. As a result, the permanent magnets 50 are not damaged when they are inserted, improving productivity. Furthermore, no extra stress is applied to the rotor core 8 when the permanent magnets 50 are inserted, improving the strength of the rotor core 8. Moreover, a flow path is secured for flowing resin from the flux barrier 22 of the second rotor core 20 through the openings 29 toward the gaps 27 between the permanent magnets 50 and the magnet insertion holes 21, which is advantageous for improving the adhesive strength of the permanent magnets 50.

[0032] (Modification of the first embodiment) Furthermore, the following modification of the above-described first embodiment can be considered. In the first embodiment described above, a pair of V-shaped magnet insertion holes 11, 21 are configured in three layers in the radial direction, and a permanent magnet 50 is installed inside each magnet insertion hole 11, 21. This three-layer structure is preferable because the distance between the opposing inner surfaces 15 and 16 and the inner surfaces 25 and 26 on the long sides of the magnet insertion holes 11, 21, and the thickness of the permanent magnet 50 in the short side direction are smaller than in a single-layer or two-layer structure, thereby suppressing demagnetization of the permanent magnet 50 caused by magnetic flux flowing from the guide portion 13 to the permanent magnet 50. However, this is not limiting, and a single-layer or two-layer structure may also be used. Furthermore, the magnet insertion holes 11, 21 may not be V-shaped, but may instead have a flat plate structure parallel to the circumferential direction.

[0033] In addition, the recess 23 provided in the second rotor core 20 expands the flow path from the flux barrier 22 to the permanent magnet 50 and the gap 27, thereby promoting the flow of resin therethrough, which is an advantageous structure for improving the adhesive strength of the permanent magnet 50.

[0034] However, this configuration is not limiting, and for example, as shown in Figure 10, a configuration can be adopted in which a step portion 28 is provided in the magnet insertion hole 21 of the second rotor core 20 at a position away from the corners at both ends of the long side of the permanent magnet 50, and the gap between this step portion 28 and the corners at both ends of the long side of the permanent magnet 50 is made into an opening 29.

[0035] With this configuration, an opening 29 of a width that does not significantly impede the flow of fluid is formed between the corner of the permanent magnet 50 and the step portion 28, making it possible to ensure a path for the resin to pass from the flux barrier 22 through the opening 29 and into the gap 27 between the permanent magnet 50 and the magnet insertion hole 21, thereby achieving the same effect as when a recess 23 is provided.

[0036] Furthermore, for either the first or second rotor core 10, 20, for example the second rotor core 20, as shown in FIG. 11, it is also possible to provide a guide portion 24 that regulates the position of the permanent magnet 50 at a position facing the corner at one end of the long side of the permanent magnet 50, and to provide an opening 29 consisting of a recess 23 at a position facing the corner at the other end of the long side of the permanent magnet 50.

[0037] Even in this configuration, the gap 27 between the permanent magnet 50 and the magnet insertion hole 21 can be utilized as a flow path for flowing fluids such as resin through the opening 29 from the flux barrier 22, and the same effect can be obtained as in the configuration in this embodiment 1 in which two types of rotor cores, the first rotor core 10 and the second rotor core 20, are combined.

[0038] Furthermore, the rotor core 8 is not limited to being made up of only two types of rotor cores, the first rotor core 10 and the second rotor core 20. For example, in addition to the first and second rotor cores 10, 20, rotor core 8 can also be made up by laminating them in an axially mixed manner, including a configuration such as that shown in Fig. 11. Note that the configuration is not limited to that shown in Fig. 11, and it is also possible to use a shape that does not have any characteristic configuration such as guide portion 13 or recess 23, as long as it has a magnet insertion hole that can at least insert permanent magnet 50 without hindrance.

[0039] Embodiment 2 Figure 12 is an enlarged cross-sectional view of one magnetic pole in which a permanent magnet 50 is attached to a first rotor core 10 that constitutes a permanent magnet type rotating electric machine according to embodiment 2, Figure 13 is an enlarged cross-sectional view of one magnetic pole in which a permanent magnet 50 is attached to a second rotor core 20 that constitutes a permanent magnet type rotating electric machine according to embodiment 2, and Figure 14 is a cross-sectional view along line B-B in Figures 12 and 13.

[0040] In this embodiment 2, the rotor core has a first rotor core 10 and a second rotor core 20, both made of electromagnetic steel plates, and as shown in Figures 12 and 13, the first rotor core 10 and the second rotor core 20 have a pair of magnet insertion holes 11, 21 formed in a V shape so that the circumferential distance between a pair of magnet insertion holes arranged at one pole gradually increases toward the outer periphery of the rotor.

[0041] In this case, unlike in embodiment 1, the pair of magnet insertion holes 11, 21 have a single-layer structure in the radial direction and are formed to penetrate in the axial direction. As in embodiment 1, a permanent magnet 50 in the shape of a strip with a rectangular cross section is fitted into each magnet insertion hole 11, 21 to form one magnetic pole of the rotating electric machine.

[0042] In this second embodiment, as in the first embodiment described above, gaps 17, 27 are formed between the flux barriers 12, 22 and the permanent magnets 50 in the magnet insertion holes 11, 21 of both the first rotor core 10 and the second rotor core 20, and a guide portion 13 is formed in the magnet insertion hole 10 of the first rotor core 10, and a recess 23 is formed in the magnet insertion hole 21 of the second rotor core 20, serving as an opening 29 connecting the flux barrier 22 to the gap 27. The first rotor cores 10 and second rotor cores 20 having the above configuration are stacked in a mixed state in the axial direction to form the rotor core 8.

[0043] As a feature of the second embodiment, as shown in FIG. 14 , end plates 71 and 72 are provided at both axial ends of the rotor 5. In this case, a space 73 is formed between one end plate 71 and one end of the rotor core 8 in the axial direction, and this space 73 communicates with the flux barriers 12 and 22 located radially inside the magnet insertion holes 11 and 21 of the first and second rotor cores 10 and 20. The other end plate 72 is formed with a pair of through holes 75 and 76 that penetrate outward in the axial direction. One through hole 75 is configured to communicate with the flux barriers 12 and 22 located radially inside the magnet insertion holes 11 and 21, and the other through hole 76 is configured to communicate with the flux barriers 12 and 22 located radially outside the magnet insertion holes 11 and 21, respectively. Furthermore, the rotating shaft 4 is formed with a hollow portion 41 into which a refrigerant fluid flows along the axial direction, and a through hole 42 is formed to discharge the fluid from the hollow portion 41 into the space 73.

[0044] Therefore, the refrigerant fluid (e.g., oil in this case) can flow into the space from the hollow portion 41 of the rotating shaft 4 through the through-holes 42, as shown by the dashed arrows in Figure 14. This fluid then flows into the flux barriers 12, 22 of one of the first and second rotor cores 10, 20, and is discharged to the outside of the rotor 5 through one of the through-holes 75 in the end plate. Also, as shown by the dashed arrow 100 in Figure 15, the fluid flows from one of the flux barriers 22 of the second rotor core 20, passing through the recess 23 and gap 27 that are openings, to the other flux barrier 22. The fluid then flows out along the axial direction, also flows into the flux barrier 12 of the first rotor core 10, and is finally discharged to the outside of the rotor 5 through the other of the through-holes 76 in the end plate 72.

[0045] With the above configuration, oil as a refrigerant not only flows through the flux barriers 12, 22 of the first and second rotor cores 10, 20, but also flows through the recesses 23 of the second rotor core 20 into the gaps 27 between the permanent magnets 50, as shown in FIG. 15 . This increases the area over which the permanent magnets 50 are directly cooled by oil, making it possible to reduce the temperature of the permanent magnets 50. Note that while oil has been used as an example of the refrigerant fluid here, the temperature of the permanent magnets 50 can also be reduced if air is used as the refrigerant. If air is used, no external equipment (not shown) for flowing oil is required, which leads to cost reduction.

[0046] In this second embodiment, instead of providing recesses 23 in the magnet insertion hole 21 of the second rotor core 20 at positions facing the corners at both ends of the long side of the permanent magnet 50, a configuration can be adopted in which, as shown in Figure 10, step portions 28 are provided at positions away from the corners at both ends of the long side of the permanent magnet 50, and the gaps between these step portions 28 and the corners at both ends of the long side of the permanent magnet 50 are openings 29.

[0047] As described above, in the permanent magnet rotating electric machine of this second embodiment, as in the first embodiment, there are gaps 17, 27 between the permanent magnets 50 and the magnet insertion holes 11, 21, which makes it easier to insert the permanent magnets 50 into the magnet insertion holes 11, 21, prevents damage to the permanent magnets 50 when inserting the magnets, and improves productivity. In addition, no extra stress is applied to the rotor core 8 when inserting the permanent magnets 50, improving the strength of the rotor core 8. Moreover, a flow path is secured for flowing a fluid such as resin or refrigerant from the flux barrier 22 toward the gap 27 between the permanent magnets 50 and the magnet insertion holes 21, resulting in a structure that is advantageous for improving the adhesive strength of the permanent magnets 50 and improving cooling performance.

[0048] In the first and second embodiments described above, the guide portions 13 of the magnet insertion holes 11 of the first rotor core 10 are provided at both ends of the long sides of the permanent magnet 50, but they may be formed at only one end of the long sides. Also, the recesses 23 that become the openings 29 of the magnet insertion holes 21 of the second rotor core 20 are formed at both ends of the long sides of the permanent magnet 50, but they may be formed at only one end of the long sides. Even in this case, the basic effects of the present application described in the first and second embodiments can be similarly obtained.

[0049] Furthermore, in each of the first and second embodiments, the permanent magnet 50 has been described as having a rectangular cross section in a plane view in a direction perpendicular to the axial direction, but it is also possible to use a permanent magnet 50 having a curved cross section such as an arc shape. Even in the case of such a shape, by providing a guide portion 13 in the magnet insertion hole 11 of the first rotor core 10 and a recess 23 that serves as an opening 29 in the magnet insertion hole 21 of the second rotor core 20, the same effects as in each of the first and second embodiments can be obtained.

[0050] Although various exemplary embodiments are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.

[0051] Therefore, countless variations not illustrated are conceivable within the scope of the technology disclosed in this application, including, for example, cases in which at least one component is modified, added, or omitted, and cases in which at least one component is extracted and combined with a component of another embodiment. [Explanation of symbols]

[0052] 1 stator, 2 stator core, 4 rotating shaft, 5 rotor, 8 rotor core, 10 first rotor core, 11 magnet insertion hole, 12 flux barrier, 13 guide portion, 15 inner surface, 16 inner surface, 17 gap, 20 second rotor core, 21 magnet insertion hole, 22 flux barrier, 23 recess, 24 guide portion, 25 inner surface, 26 inner surface, 27 gap, 28 step portion, 29 opening, 50 permanent magnet, 60 resin.

Claims

1. A permanent magnet type rotating electric machine comprising: a stator; and a rotor rotatably supported by a rotating shaft inside the stator, the rotor having a rotor core formed by stacking a plurality of electromagnetic steel plates in the axial direction, a plurality of magnet insertion holes formed in the rotor core, and strip-shaped permanent magnets attached to the magnet insertion holes so as to pass through the magnet insertion holes in the axial direction, the rotor core has a first rotor core and a second rotor core, and the magnet insertion holes formed in the first rotor core and the second rotor core are provided with flux barriers on both sides of the permanent magnet in the width direction to prevent leakage of magnetic flux, and the distance between opposing faces in the thickness direction of the permanent magnet is set to be larger than the thickness of the permanent magnet, thereby forming a gap between the permanent magnet and the magnet insertion hole, The magnet insertion hole of the first rotor core is formed with a guide portion for positioning the permanent magnet in the width direction on at least one end side of the permanent magnet in the width direction, and an opening communicating the gap with the flux barrier is formed in the magnet insertion hole of the second rotor core, a permanent magnet type rotating electric machine in which the first rotor core and the second rotor core are stacked in a mixed manner in the axial direction;

2. The guide portion is so that the path from the flux barrier region to the gap region is narrowed; 2. The permanent magnet type rotating electric machine according to claim 1, wherein the flux barrier is formed at a position facing a corner of the permanent magnet, the corner being sandwiched between the flux barrier region and the gap.

3. 2. The permanent magnet rotating electric machine according to claim 1, wherein the opening has a recess formed on an inner surface on the radially inner side at a position facing a corner of the permanent magnet, and the recess is configured as the opening spanning the corner of the permanent magnet.

4. 2. The permanent magnet rotating electric machine according to claim 1, wherein the gap is formed between a radially inner inner surface of the magnet insertion hole and a radially inner surface of the permanent magnet facing the inner surface, and the flux barrier and the gap are filled with resin.

5. The permanent magnet type rotating electric machine according to claim 4 , wherein at least a portion of the permanent magnet is in contact with an inner surface on a radially outer side of the magnet insertion hole.

6. 6. The permanent magnet type rotating electric machine according to claim 1, wherein the magnet insertion holes and the permanent magnets are arranged in a V-shape that protrudes radially inward of the rotor.

7. 6. The permanent magnet type rotating electric machine according to claim 1, wherein the magnet insertion holes and the permanent magnets are arranged in two or more layers in the radial direction of the rotor.

8. 6. A permanent magnet type rotating electric machine according to claim 1, wherein the permanent magnet is divided into a plurality of pieces in the axial direction of the rotor, and at least one first rotor core is arranged within a range corresponding to the axial length of one of the divided permanent magnets.

9. The permanent magnet type rotating electric machine according to claim 1 , wherein a coolant flows through the flux barrier, the gap, and the opening of the second rotor core.

10. The permanent magnet type rotating electric machine according to claim 9 , wherein the refrigerant is oil or air.

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