Rotating electrical machine

Abstract

To provide a rotary electric machine capable of improving a degree of freedom of magnetic sensor arrangement while suppressing an increase in the number of components.SOLUTION: A rotary electric machine comprises: a rotor 20 provided with permanent magnets 23 embedded respectively in magnet housing holes 24 in a rotor core 22; a stator for applying rotating magnetic field to the rotor 20; and a magnetic sensor 30 for detecting rotation information of the rotor 20. The permanent magnets 23 have a folded shape protruding inward a radial direction of the rotor 20. The magnetic sensor 30 is configured to face the permanent magnets 23 so as to be able to detect a magnetic flux of the permanent magnets 23.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine.

Background Art

[0002] For example, the rotor of the rotating electrical machine disclosed in Patent Document 1 includes a rotor body having a rotor magnet facing the stator on the outer peripheral surface of the rotor core, and a sensor magnet provided separately from the rotor body. The rotor is a surface magnet type rotor having a rotor magnet on the outer peripheral surface of the rotor core. Further, the rotating electrical machine includes a magnetic sensor disposed in the vicinity of the sensor magnet so that the magnetic flux of the sensor magnet can be detected. And, based on the signal output from the magnetic sensor, it is possible to obtain rotation information such as the rotation position of the rotor. In this rotating electrical machine, since the sensor magnet is provided separately from the rotor body, there is room for improvement in terms of suppressing the number of parts.

[0003] Therefore, for example, in the rotating electrical machine of Patent Document 2, the sensor magnet is integrally formed with the rotor magnet. Specifically, a part of the rotor magnet is projected axially from the end face of the rotor core. Then, the projecting portion is used as the sensor magnet, and a magnetic sensor is disposed in the vicinity of the projecting portion. Thereby, the rotor magnet and the sensor magnet can be made into one integrated part, and as a result, an increase in the number of parts can be suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a rotating electrical machine such as the above-mentioned Patent Document 2, the magnetic sensor is provided in the vicinity of the protruding portion of a rotor magnet disposed on the outer peripheral surface of a rotor core. Therefore, there has been a problem that the arrangement position of the magnetic sensor in the radial direction is limited to the vicinity of the outer peripheral surface of the rotor core.

[0006] An object of the present invention is to solve the above problems. That is, it is an object of the present invention to provide a rotating electrical machine capable of improving the degree of freedom in arranging a magnetic sensor while suppressing an increase in the number of components.

Means for Solving the Problems

[0007] A rotating electrical machine for solving the above problems includes a rotor (20) having a permanent magnet (23) embedded in a magnet accommodation hole (24) of a rotor core (22), a stator (10) that applies a rotating magnetic field to the rotor, and a magnetic sensor (30) for detecting rotation information of the rotor. The permanent magnet has a folded-back shape convex toward the inner side in the radial direction of the rotor, and the magnetic sensor is configured to be able to detect the magnetic flux of the permanent magnet facing the permanent magnet.

[0008] According to this configuration, it is possible to obtain rotation information of the rotor based on the magnetic flux of the permanent magnet of the rotor detected by the magnetic sensor. That is, it is possible to detect the rotation of the rotor without providing a sensor magnet for rotation detection separately from the permanent magnet provided in the rotor. Therefore, it is possible to suppress an increase in the number of components. Further, the permanent magnet provided in the rotor is not provided on the outer peripheral surface of the rotor core but is embedded in the rotor core. Furthermore, the permanent magnet has a folded-back shape convex toward the inner side in the radial direction of the rotor. For this reason, the region where the permanent magnet is provided in the rotor becomes wider in the radial direction. Therefore, it is possible to configure the arrangement position of the magnetic sensor not to be limited to the vicinity of the outer peripheral surface of the rotor core. As a result, it is possible to improve the degree of freedom in arranging the magnetic sensor.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, an embodiment of a rotating electrical machine will be described. The rotating electrical machine M of the present embodiment shown in FIGS. 1 and 2 is configured by an embedded magnet type brushless motor. The rotating electrical machine M includes a substantially annular stator 10 and a substantially columnar rotor 20 rotatably disposed in the radially inner space of the stator 10. The stator 10 applies a rotating magnetic field to the rotor 20.

[0011] (Stator 10) The stator 10 includes a substantially annular stator core 11. The stator core 11 is made of a magnetic metal material. The stator core 11 is formed, for example, by laminating a plurality of electromagnetic steel sheets in the direction of the axis L1 (see FIG. 4). In the present embodiment, the stator core 11 has 12 teeth 12 that extend radially inward and are arranged at equal intervals in the circumferential direction. Each of the teeth 12 has the same shape as each other. The teeth 12 have a substantially T-shaped radially inner end portion, which is the tip end portion, and an arc-shaped tip surface 12a that follows the outer peripheral surface of the rotor 20. A winding 13 is wound around the teeth 12 in a concentrated winding manner. The winding 13 is connected in a three-phase configuration and functions as the U-phase, V-phase, and W-phase as shown in FIG. 1, respectively. When power is supplied to the winding 13, a rotating magnetic field for rotating the rotor 20 is generated in the stator 10. Such a stator 10 has the outer peripheral surface of the stator core 11 fixed to the inner peripheral surface of the housing 14.

[0012] (Rotor 20) The rotor 20 includes a rotating shaft 21, a substantially cylindrical rotor core 22 into which the rotating shaft 21 is inserted at the center, and eight permanent magnets 23 that are embedded inside the rotor core 22 in the present embodiment. The rotor core 22 is made of a magnetic metal material. The rotor core 22 is formed, for example, by laminating a plurality of electromagnetic steel sheets in the direction of the axis L1 shown in FIG. 4. The rotor 20 is rotatably arranged with respect to the stator 10 by being supported by bearings (not shown) provided on the housing 14 for the rotating shaft 21.

[0013] The rotor core 22 has magnet accommodation holes 24 for accommodating the permanent magnets 23. In the present embodiment, eight magnet accommodation holes 24 are provided at equal intervals in the circumferential direction of the rotor core 22. Each of the magnet accommodation holes 24 has a substantially V-shaped folded-back shape that protrudes radially inward and has the same shape as each other. Further, the magnet accommodation holes 24 are provided throughout the entire axial direction of the rotor core 22.

[0014] Here, the permanent magnet 23 of the present embodiment is a bonded magnet formed by molding and solidifying a magnet material in which magnet powder is mixed with resin. That is, the permanent magnet 23 uses the magnet accommodation hole 24 of the rotor core 22 as a molding die, and the magnet material before solidification is filled into the magnet accommodation hole 24 without gaps by injection molding and solidified in the magnet accommodation hole 24 after filling. Therefore, the hole shape of the magnet accommodation hole 24 becomes the outer shape of the permanent magnet 23. Further, the permanent magnet 23 of the present embodiment is configured to partially protrude from the axial end faces 22c and 22d of the rotor core 22 (see FIG. 4 etc.). The permanent magnet 23 has an embedded magnet portion 23m in the magnet accommodation hole 24 and protruding portions 23x1 and 23y1 protruding from the axial end faces 22c and 22d of the rotor core 22. Regarding the protruding portions 23x1 and 23y1 of the permanent magnet 23, it can be easily realized by simply providing recesses for forming the protruding portions 23x1 and 23y1 in a molding die (not shown) for closing the magnet accommodation hole 24 that opens to the axial end faces 22c and 22d of the rotor core 22. As the magnet powder used for the permanent magnet 23 of the present embodiment, for example, a samarium iron nitride (SmFeN) - based magnet is used, but other rare - earth magnets etc. may also be used.

[0015] The permanent magnet 23 has a substantially V - shaped folded shape that is convex toward the inner side in the radial direction. More specifically, as shown in FIG. 3, the permanent magnet 23 has a shape in which the inner ends in the radial direction of a pair of straight portions 23a are connected by a bent portion 23b. The outer ends 23c in the radial direction of the straight portions 23a are located near the outer peripheral surface 22a of the rotor core 22. The permanent magnet 23 has a thickness Wm set to be constant in any of the V - shaped paths including the pair of straight portions 23a and the bent portion 23b. The permanent magnet 23 has a line - symmetric shape with respect to its circumferential center line Ls passing through the axis center O1 of the rotor 20 and is close to the magnetic - pole boundary line Ld passing through the axis center O1 of the rotor 20 between adjacent permanent magnets 23. The angle between adjacent magnetic - pole boundary lines Ld, that is, the magnetic - pole opening angle θm of the rotor magnetic - pole portion 26 including this permanent magnet 23 is 180° in electrical angle.

[0016] Here, the magnetic pole pitch Lp is defined as the distance between the intersections of the extension lines of the inner surfaces of the straight portions 23a of the permanent magnet 23 having a V shape and the outer peripheral surface 22a of the rotor core 22, and the embedding depth Lm is defined as the distance from the outer peripheral surface 22a of the rotor core 22 to the inner surface of the bent portion 23b on the circumferential center line Ls of the permanent magnet 23. The permanent magnet 23 of the present embodiment is set to a deep folding shape such that the embedding depth Lm is larger than the magnetic pole pitch Lp. That is, the magnet surface 23d of the permanent magnet 23 of the present embodiment formed by the inner surfaces of the respective straight portions 23a and the bent portions 23b is set to be larger than the magnet surface (not shown) of the well-known surface magnet type. Further, by setting the embedding depth Lm to be large, the bent portion 23b of the permanent magnet 23 is located closer to the radially inner side near the shaft insertion hole 22b into which the rotation shaft 21 at the center of the rotor core 22 is inserted. Note that this folding shape of the permanent magnet 23 is an example, and it can be appropriately changed, such as a shape with a shallow embedding depth Lm or a substantially U-shaped folding shape with a large bent portion 23b. Since the permanent magnet 23 has a substantially V-shaped folding shape that protrudes radially inward, it is easy to widen the region where the permanent magnet 23 in the radial direction is provided compared to the aforementioned surface magnet type rotor.

[0017] Further, as shown in FIGS. 4 and 5, the permanent magnet 23 is provided over the entire axial direction of the rotor core 22. The axial end faces 22c and 22d of the rotor core 22 are flat surfaces, and the permanent magnet 23 has protruding portions 23x1 and 23y1 that protrude axially from the axial end faces 22c and 22d of the rotor core 22. The protruding portions 23x1 and 23y1 are continuous in a V-shaped path including the straight portion 23a and the bent portion 23b of the permanent magnet 23 and have a constant thickness Wm. The protruding portions 23x1 and 23y1 are provided on the respective axial end faces 22c and 22d of the rotor core 22, one on each side. The protruding portions 23x1 and 23y1 are continuously and integrally provided with the same material as the embedded magnet portion 23m of the permanent magnet 23 located in the magnet accommodation hole 24 of the rotor core 22.

[0018] Such protrusions 23x1 and 23y1 of the permanent magnet 23 are the end portions of the permanent magnet 23 located on the axial end faces 22c and 22d of the rotor core 22, and function to generate leakage magnetic flux φb shown in FIG. 4 that is likely to occur at the end portions of the permanent magnet 23 at this site. In other words, more of the magnetic flux of the embedded magnet portion 23m located within the rotor core 22 of the permanent magnet 23 is made to flow along the radial direction without leaking to the outside from the axial end faces 22c and 22d, so that more magnetic flux becomes the effective magnetic flux φa contributing to the torque of the rotating electrical machine M. The protrusions 23x1 and 23y1 are set so as to have an appropriate protrusion amount D1 from the axial end faces 22c and 22d of the rotor core 22 while aiming to increase the effective magnetic flux φa. Note that the protrusion amount D1 of the protrusions 23x1 and 23y1 may differ from the dimensions shown in the figure and the actual dimensions.

[0019] The permanent magnet 23 mainly provided in the magnet accommodation hole 24 of the rotor core 22 is magnetized from the outside of the rotor core 22 using a magnetization device (not shown in detail) so as to function as a proper magnet after the magnet material is solidified. In the present embodiment, eight permanent magnets 23 are provided in the circumferential direction of the rotor core 22, and are magnetized so as to have different polarities alternately in the circumferential direction. Also, each permanent magnet 23 is magnetized in its own thickness direction.

[0020] The portion of the rotor core 22 that is inside the V-shaped bent shape of the permanent magnet 23 and is located radially outside the permanent magnet 23 functions as an outer core portion 25 for obtaining reluctance torque by facing the stator 10. The outer core portion 25 has a substantially triangular shape with one vertex facing the center portion direction of the rotor 20 in the axial view. And the rotor 20 is configured as an eight-pole rotor magnetic pole portion 26 including the permanent magnet 23 and the outer core portion 25 surrounded inside the V-shaped shape of the permanent magnet 23 in the present embodiment. Each rotor magnetic pole portion 26 functions as an N pole and an S pole alternately in the circumferential direction as shown in FIG. 1. In the rotor 20 having such rotor magnetic pole portions 26, magnetic torque and reluctance torque can be suitably obtained.

[0021] (Magnetic sensor 30) As shown in FIG. 2, the rotating electrical machine M includes a magnetic sensor 30 for detecting rotation information including the rotational position, rotational speed, etc. of the rotor 20. For the magnetic sensor 30, a Hall element, a Hall IC, etc. can be used. The magnetic sensor 30 is provided on a circuit board 31 supported by the housing 14. The magnetic sensor 30 is arranged so as to face axially the protruding portion 23x1 on one side in the axial direction. For example, no other member is interposed axially between the magnetic sensor 30 and the protruding portion 23x1. That is, the magnetic sensor 30 is enabled to detect the magnetic flux from the protruding portion 23x1. During rotation of the rotor 20, it is possible to obtain the rotation information of the rotor 20 based on a signal corresponding to the magnetic flux density output from the magnetic sensor 30.

[0022] As shown in FIG. 3, let the distance from the outer peripheral surface 22a in the axial view to the center of the magnetic sensor 30 be the sensor position Ps. For example, the sensor position Ps is set such that the relationship with the embedding depth Lm satisfies Ps < Lm. Also, for example, the magnetic sensor 30 is provided at a position axially overlapping the straight portion 23a of the permanent magnet 23.

[0023] As shown in FIG. 4, let the distance from the rotor core 22 to the magnetic sensor 30 in the axial direction be Hs. Also, let the distance from the protruding portion 23x1 to the magnetic sensor 30 in the axial direction be Hm. For example, the distance Hs is configured such that the relationship with the distance Hm satisfies Hm < Hs.

[0024] The operation of this embodiment will be described. In the configuration of the rotor 20 of the present embodiment, the permanent magnets 23 embedded in the rotor core 22 project the ends of the permanent magnets 23 as protruding portions 23x1 and 23y1 from the axial end faces 22c and 22d on both sides of the rotor core 22, respectively. By making the ends of the permanent magnets 23 into the protruding portions 23x1 and 23y1, the leakage magnetic flux φb generated at the ends of the permanent magnets 23 becomes concentrated in the protruding portions 23x1 and 23y1. Further, in the embedded magnet portion 23m of the permanent magnet 23 located within the rotor core 22, since the path of the magnetic flux when it tries to leak from the axial end faces 22c and 22d of the rotor core 22 is in a mode that crosses the protruding portions 23x1 and 23y1, the path length of the magnetic flux becomes longer. Therefore, the magnetic flux in the embedded magnet portion 23m is suppressed from leaking out from the axial end faces 22c and 22d of the rotor core 22, and the magnetic flux generated in the embedded magnet portion 23m flows along the radial direction within the rotor core 22 over the entire axial direction. In this way, most of the magnetic flux generated over the entire axial direction of the embedded magnet portion 23m becomes the effective magnetic flux φa that contributes to the torque of the rotating electrical machine M, and it is possible to increase the magnetic flux amount of the effective magnetic flux φa.

[0025] FIG. 6(a) shows the comparison results between the present embodiment and the comparative example. The present embodiment has a configuration in which the ends of the permanent magnets 23 are projected as protruding portions 23x1 and 23y1 from the axial end faces 22c and 22d on both sides of the rotor core 22 described above. The comparative example is a conventionally well-known configuration in which the ends of the permanent magnets 23 are not projected from the axial end faces 22c and 22d of the rotor core 22. This is a comparison with the present embodiment when the comparative example is set to 100 in terms of the induced voltage Vm generated in the rotating electrical machine M and the induced voltage / magnet volume (Vm / Va) obtained by dividing the induced voltage by the volume of the permanent magnet 23.

[0026] Regarding the induced voltage Vm, it becomes sufficiently larger in this embodiment than in the comparative example. This is because the leakage magnetic flux φb is generated at the protruding portions 23x1 and 23y1, so that most of the magnetic flux of the embedded magnet portion 23m of the permanent magnet 23 becomes the effective magnetic flux φa, and the effective magnetic flux φa increases. As shown in FIG. 6(b) regarding the relationship between the protruding amount D1 of the protruding portions 23x1 and 23y1 and the induced voltage Vm, it can be seen that when the protruding amount D1 of the protruding portions 23x1 and 23y1 is zero or more, that is, by protruding, the effective magnetic flux φa increases and the induced voltage Vm also increases. On the other hand, regarding the induced voltage / magnet volume (Vm / Va), since the magnet volume Va increases by providing the protruding portions 23x1 and 23y1, it becomes smaller than the comparative example. As shown in FIG. 6(c) regarding the relationship between the protruding amount D1 and the induced voltage / magnet volume (Vm / Va), it can be seen that the Vm / Va value gradually decreases due to the increase in the magnet volume Va caused by the protrusion of the protruding portions 23x1 and 23y1. Considering such a relationship between the protruding amount D1 of the protruding portions 23x1 and 23y1 and the induced voltage Vm and the induced voltage / magnet volume (Vm / Va), the protruding amount D1 is appropriately set. Also, since an increase in the protruding amount D1 leads to an increase in the weight of the rotor 20 and an increase in the magnet material of the permanent magnet 23, etc., it is also preferable to consider this when setting the protruding amount D1.

[0027] The graph shown in FIG. 7 shows the relationship between the ratio Ps / Lm of the sensor position Ps to the embedded depth Lm and the magnetic flux density detected by the magnetic sensor 30. In this graph, regardless of the magnitude of the ratio Ps / Lm, the ratio Hm / Hs of the distance Hm to the distance Hs is kept constant at, for example, 0.71. As shown in the figure, when the ratio Ps / Lm is within the range of 0.10 ≦ Ps / Lm ≦ 0.93, a state where the magnetic flux density detected by the magnetic sensor 30 is high is maintained. And when the ratio Ps / Lm is increased, in the range where the ratio Ps / Lm exceeds 0.93, the magnetic flux density detected by the magnetic sensor 30 greatly decreases. Therefore, if the ratio Ps / Lm is set to be within the range of 0.10 ≦ Ps / Lm ≦ 0.93, it becomes possible to easily secure the magnetic flux density necessary for the rotation detection of the rotor 20.

[0028] The graph shown in Fig. 8 shows the relationship between the ratio Hm / Hs of the distance Hm to the distance Hs and the magnetic flux density detected by the magnetic sensor 30. In this graph, the ratio Ps / Lm is kept constant at, for example, 0.44 regardless of the magnitude of the ratio Hm / Hs. As shown in the figure, the smaller the ratio Hm / Hs, the larger the magnetic flux density detected by the magnetic sensor 30. If the ratio Hm / Hs is within the range of Hm / Hs ≦ 0.8, it is possible to easily ensure the magnetic flux density required for detecting the rotation of the rotor 20.

[0029] The effects of this embodiment will be described. (1) The permanent magnet 23 has a convex folded shape inside the rotor 20 in the radial direction. The magnetic sensor 30 is configured to be able to detect the magnetic flux of the permanent magnet 23 facing the permanent magnet 23. According to this configuration, it is possible to obtain the rotation information of the rotor 20 based on the magnetic flux of the permanent magnet 23 of the rotor 20 detected by the magnetic sensor 30. That is, even if a sensor magnet for rotation detection is not provided separately from the permanent magnet 23 provided in the rotor 20, it is possible to detect the rotation of the rotor 20. Therefore, it is possible to suppress an increase in the number of parts. Further, the permanent magnet 23 provided in the rotor 20 is not provided on the outer peripheral surface of the rotor core 22, but is embedded in the rotor core 22. Furthermore, the permanent magnet 23 has a convex folded shape inside the rotor 20 in the radial direction. For this reason, the region where the permanent magnet 23 is provided in the rotor 20 becomes wider in the radial direction. Therefore, it is possible to configure the arrangement position of the magnetic sensor 30 not to be limited to the vicinity of the outer peripheral surface of the rotor core 22. As a result, it is possible to improve the degree of freedom in arranging the magnetic sensor 30.

[0030] (2) On the circumferential center line Ls of the permanent magnet 23, the embedding depth Lm is defined as the distance from the outer peripheral surface 22a of the rotor core 22 to the inner surface of the bent portion 23b of the permanent magnet 23. Also, the distance from the outer peripheral surface 22a to the center of the magnetic sensor 30 in the axial direction view is defined as the sensor position Ps. And the embedding depth Lm and the sensor position Ps are configured to satisfy Ps < Lm. According to this configuration, in the radial direction, the magnetic sensor 30 will be located outside the bent portion 23b. Thereby, it becomes possible to suitably detect the magnetic flux of the permanent magnet 23 with the magnetic sensor 30.

[0031] (3) The ratio Ps / Lm of the sensor position Ps to the embedding depth Lm is configured to satisfy 0.10 ≦ Ps / Lm ≦ 0.93. According to this configuration, as shown in FIG. 7, it becomes possible to easily secure the magnetic flux density necessary for detecting the rotation of the rotor 20.

[0032] (4) The axial end faces 22c, 22d of the rotor core 22 form flat surfaces. The permanent magnet 23 has protruding portions 23x1, 23y1 protruding from the axial end faces 22c, 22d of the rotor core 22, respectively. And the magnetic sensor 30 is capable of detecting the magnetic flux from the protruding portion 23x1 on one axial side.

[0033] According to this configuration, the ends of the permanent magnets 23 protrude as protruding portions 23x1 and 23y1 from the axial end faces 22c and 22d that form the flat surfaces of the rotor core 22. For this reason, in order for the magnetic flux of the embedded magnet portions 23m of the permanent magnets 23 located within the rotor core 22 to leak out from the axial end faces 22c and 22d of the rotor core 22, it has to pass beyond those protruding portions 23x1 and 23y1. That is, since the path length for the magnetic flux of the embedded magnet portions 23m to leak out becomes longer, leakage of the magnetic flux of the embedded magnet portions 23m can be suppressed. Since the magnetic flux of the embedded magnet portions 23m of the permanent magnets 23 becomes the effective magnetic flux φa that contributes to the torque of the rotating electrical machine M, by preventing this from leaking out as much as possible and increasing the amount of the magnetic flux of the effective magnetic flux φa, a sufficient improvement in the torque performance of the rotating electrical machine M can be expected. Moreover, the axial end faces 22c and 22d of the rotor core 22 have a general flat surface shape, and can be realized by a simple measure of protruding the ends of the permanent magnets 23 from the axial end faces 22c and 22d of the rotor core 22. Also, since the magnetic sensor 30 detects the magnetic flux from the protruding portion 23x1 that protrudes from the rotor core 22, the magnetic flux of the permanent magnet 23 can be suitably detected by the magnetic sensor 30.

[0034] (5) Since the magnetic sensor 30 is arranged so as to face the protruding portion 23x1 in the axial direction, the magnetic flux of the protruding portion 23x1 can be suitably detected by the magnetic sensor 30. (6) Let the distance from the rotor core 22 to the magnetic sensor 30 in the axial direction be Hs. Also, let the distance from the protruding portion 23x1 to the magnetic sensor 30 in the axial direction be Hm. And, the distance Hm and the distance Hs are configured such that Hm < Hs is satisfied. According to this configuration, the distance Hm from the protruding portion 23x1 to the magnetic sensor 30 becomes smaller than the distance Hs from the rotor core 22 to the magnetic sensor 30. Thereby, the magnetic flux of the protruding portion 23x1 can be suitably detected by the magnetic sensor 30.

[0035] (7) The ratio Hm / Hs of the distance Hm to the distance Hs is configured such that Hm / Hs ≦ 0.8 is satisfied. According to this configuration, as shown in FIG. 8, it becomes possible to easily secure the magnetic flux density required for detecting the rotation of the rotor 20.

[0036] (8) Since the protruding portions 23x1 and 23y1 of the salient poles are provided such that the protruding amount D1 from the axial end faces 22c and 22d of the rotor core 22 is constant, leakage of magnetic flux from the embedded magnet portions 23m contributing to torque can be suppressed similarly at each location.

[0037] (9) Since the protruding portions 23x1 and 23y1 of the permanent magnet 23 have the same protruding shape from the axial end faces 22c and 22d on both sides of the rotor core 22, effects such as maintaining good weight balance of the rotor 20 can be obtained.

[0038] (10) The protruding portions 23x1 and 23y1 of the permanent magnet 23 are provided continuously in the extending direction of the V-shaped permanent magnet 23 along the axial end faces 22c and 22d of the rotor core 22. For this reason, leakage of magnetic flux from the embedded magnet portions 23m contributing to torque can be more reliably suppressed over the entire permanent magnet 23.

[0039] (11) Since the protruding portions 23x1 and 23y1 of the permanent magnet 23 are provided continuously and integrally from the embedded magnet portions 23m of the rotor core 22, they can be easily formed, such as being formed simultaneously from the same material.

[0040] (12) Since the protruding portions 23x1 and 23y1 of the permanent magnet 23 are provided for all the permanent magnets 23 arranged in the circumferential direction of the rotor 20, leakage of magnetic flux from the embedded magnet portions 23m contributing to torque can be suppressed in all the permanent magnets 23. Also, effects such as maintaining good weight balance of the rotor 20 can be obtained.

[0041] This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non-conflicting range. · The configuration of the protruding portions 23x1 and 23y1 at the ends of the permanent magnet 23 protruding from the axial end faces 22c and 22d of the rotor core 22 may be appropriately changed.

[0042] For example, a protruding portion may be partially provided in a V-shaped path including the straight portion 23a and the bent portion 23b of the permanent magnet 23. For example, as shown in FIG. 9, protruding portions 23x2 and 23y2 that protrude only from the straight portion 23a of the permanent magnet 23 may be provided. The protruding portions 23x2 and 23y2 are provided in the same manner on both of the axial end faces 22c and 22d of the rotor core 22, for example.

[0043] Further, for example, a protruding portion that partially protrudes in the extending direction of the straight portion 23a may be provided. Further, for example, the protruding portion of the permanent magnet 23 may be provided only on one side of the V shape, such as one straight portion 23a and half of the bent portion 23b on one side of the V shape of the permanent magnet 23.

[0044] As described above, by partially providing the protruding portion of the permanent magnet 23 in the extending direction of the permanent magnet 23, that is, in the V-shaped path including the straight portion 23a and the bent portion 23b, the magnet material of the permanent magnet 23 can be reduced, and effects such as weight reduction of the rotor 20 can be expected.

[0045] Further, for example, the shape of the protruding portion provided on the permanent magnet 23 may be changed. The protruding amount D1 may be changed depending on the part of the protruding portion. Further, for example, protruding portions having different configurations may be provided on the axial end faces 22c and 22d of the rotor core 22, respectively.

[0046] Further, for example, in the above embodiment, the protruding portions 23x1 and 23y1 of the permanent magnet 23 may be separate from the embedded magnet portion 23m. In this case, the magnet materials of each other may be made different. According to this configuration, effects such as increasing the degree of freedom in the configuration of the permanent magnet 23 can be expected. Note that in this configuration, the protruding portions 23x1 and 23y1 that are separate from the embedded magnet portion 23m are part of the permanent magnet 23 that is a rotor magnet, and the number of parts does not increase.

[0047] ·In the above embodiment, the permanent magnet 23 is made constant in thickness Wm continuously in a V-shaped path including the straight portion 23a and the bent portion 23b of the permanent magnet 23. However, the present invention is not limited to this, and the thickness Wm of the bent portion 23b may be made narrower than the thickness Wm of the straight portion 23a.

[0048] ·In the above embodiment, the protruding portions 23x1 and 23y1 are provided for all the permanent magnets 23 arranged in the circumferential direction of the rotor 20. However, the present invention is not limited to this, and the protruding portions 23x1 and 23y1 may be provided only for some of the plurality of permanent magnets 23. According to this configuration, the magnet material of the permanent magnet 23 can be reduced, and effects such as weight reduction of the rotor 20 can be expected.

[0049] ·The permanent magnet 23 does not necessarily have to have the protruding portions 23x1 and 23y1, and one or both of the protruding portions 23x1 and 23y1 may be omitted from the configuration of the above embodiment. That is, in the above embodiment, the axial end portions of the permanent magnet 23 may be flush with the axial end faces 22c and 22d of the rotor core 22, or the axial end portions of the permanent magnet 23 may be located inside the rotor core 22. Even with such a configuration, the magnetic flux of the permanent magnet 23 can be configured to be detectable by the magnetic sensor 30.

[0050] ·The permanent magnet 23 is not limited to a V shape, and may be other folded-back shapes convex in the radial direction of the rotor 20, such as a U shape. Further, it may be a shape other than a folded-back shape, such as an I shape. ·Although the permanent magnet 23 is formed by injection molding a magnet material into the magnet accommodation hole 24 of the rotor core 22, the permanent magnet 23 may be prepared in advance and inserted and fixed into the magnet accommodation hole 24 of the rotor core 22.

[0051] ·The arrangement position of the magnetic sensor 30 is not limited to the above embodiment, and can be appropriately changed according to the configuration of the rotating electrical machine M. For example, although the magnetic sensor 30 is configured to face the protruding portion 23x1 in the axial direction, for example, the magnetic sensor 30 may be arranged to face the radially inner side surface of the bent portion 23b.

[0052] ·Other than the above, the configuration of the rotor 20 and the configuration of the rotating electric machine M may be changed as appropriate. ·The embodiments and modification examples disclosed this time are illustrative in all respects, and the present invention is not limited to these examples. That is, the scope of the present invention is indicated by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of reference numerals

[0053] M Rotating electric machine, 10 Stator, 20 Rotor, 22 Rotor core, 22a Outer peripheral surface, 22c, 22d Axial end faces, 23 Permanent magnet, 23b Bent portion, 23x1, 23y1, 23x2, 23y2 Protrusions, 24 Magnet accommodation hole, 30 Magnetic sensor, D1 Protrusion amount, Hm Distance, Hs Distance, Lm Embedding depth, Ps Sensor position, Ls Circumferential center line.

Claims

1. A rotor (20) having a permanent magnet (23) embedded in a magnet accommodation hole (24) of a rotor core (22), a stator (10) that applies a rotating magnetic field to the rotor, a magnetic sensor (30) for detecting rotation information of the rotor, A rotating electrical machine (M) comprising: The permanent magnet has a folded-back shape convex toward the inner side in the radial direction of the rotor, The magnetic sensor is configured to be able to detect the magnetic flux of the permanent magnet facing the permanent magnet, On the circumferential center line (Ls) of the permanent magnet, the depth from the outer peripheral surface (22a) of the rotor core to the inner surface of the bent portion (23b) of the permanent magnet is defined as the embedding depth (Lm), The distance from the outer peripheral surface in the axial direction view to the center of the magnetic sensor is defined as the sensor position (Ps), The axial end faces (22c, 22d) of the rotor core form flat surfaces, The permanent magnet has protruding portions (23x1, 23y1, 23x2, 23y2) at least partially protruding from the axial end faces of the rotor core, The magnetic sensor is capable of detecting the magnetic flux from the protruding portion, The magnetic sensor is arranged to face the protruding portion in the axial direction, The distance from the rotor core to the magnetic sensor in the axial direction is defined as Hs, The distance from the protruding portion to the magnetic sensor in the axial direction is defined as Hm, The ratio Ps / Lm of the sensor position to the embedding depth is configured to satisfy 0.10 ≦ Ps / Lm ≦ 0.93, and the ratio Hm / Hs of the distance Hm to the distance Hs is configured to satisfy Hm / Hs ≦ 0.

8. Rotating electrical machine.

2. The protruding portion is provided such that the amount of protrusion (D1) from the axial end face of the rotor core is constant. The rotating electrical machine according to Claim 1.

3. The protruding portion is partially provided in the extending direction of the permanent magnet. The rotating electrical machine according to Claim 1.

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