JP2013005659A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive electric motor having small cogging torque.SOLUTION: The rotor 23 of the electric motor 20 includes a rotor yoke 36. A plurality of mounting surfaces 38 are formed on the peripheral surface 361 of the rotor yoke 36, and an anisotropic segment magnet 37 is fixed to each mounting surface 38. The actual orientation direction J1 of the segment magnet 37 varies within a prescribed variation angle range δ. The actual orientation direction J1 runs parallel with the rotor diameter direction R1 passing through the magnet center CP of the segment magnet 37 or inclines toward the same side with respect to the rotor diameter direction R1. The variance center direction B1 bisecting the variation angle range δ inclines at an inclination angle θ corresponding to the half angle δ/2 of the variation angle range δ with respect to the rotor diameter direction R1.

Description

  The present invention relates to an electric motor.

For example, in an electric motor for steering assistance used in an electric power steering device, cogging torque is amplified by deceleration and transmitted to a steering member, which is experienced by a driver operating the steering member. For this reason, a driver's steering feeling may be deteriorated.
The main cause of the cogging torque is considered to be variation in the orientation direction of the anisotropic segment magnets arranged on the peripheral surface of the rotor of the electric motor. That is, in the anisotropic segment magnet, the direction of magnetic flux is generally determined at the stage of orientation. Therefore, if there is a variation in the orientation direction of the segment magnets, there will be a large variation in the electrical angle between the segment magnets where the magnetic attraction force is the greatest with respect to the teeth of the stator, resulting in a large cogging torque. .

  Therefore, at the stage of the sintered magnetic body (green compact) as an intermediate for manufacturing the segment magnet, a plurality of sintered magnetic bodies whose orientation directions are inclined in the same direction are selected and fixed to the rotor. Thereafter, a method for manufacturing a rotor that performs a magnetizing process has been proposed (see, for example, Patent Document 1).

JP 2000-171805 A

In patent document 1, since a lot of man-hours are required for the sorting operation in the manufacturing stage, there is a problem that the manufacturing cost increases. On the other hand, problems caused by cogging torque are not limited to electric motors for electric power steering, but are common to electric motors for various applications.
The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric motor that is inexpensive and has a small cogging torque.

  In order to achieve the above object, the invention of claim 1 includes a stator (24) and a rotor (23; 23A), and the rotor has a peripheral surface provided with a plurality of mounting surfaces (38; 38A). A cylindrical rotor yoke (36; 36A) having (361) and a plurality of anisotropic segment magnets (37; 37A) respectively fixed to the mounting surfaces, and the actual orientation of each segment magnet The direction (J1) varies within a predetermined variation angle range (δ), and the actual orientation direction of each segment magnet is the rotor radial direction (R1) passing through the magnet center (CP) of each segment magnet. The variation center direction (B1) that bisects the variation angle range so as to be parallel or inclined to the same side with respect to the rotor radial direction is half the variation angle range with respect to the rotor radial direction. Providing; (20A 20) electric motor which is inclined at an angle ([delta] / 2) or more inclination angle (theta).

In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter.
Further, as in claim 2, the normal direction (H1) of the corresponding mounting surface passing through the magnet center of each of the segment magnets is on the same side as the rotor radial direction passing through the magnet center. You may incline with the inclination angle equal to an inclination angle.

  Further, as in claim 3, the normal direction of the corresponding mounting surface passing through the magnet center of each segment magnet is along the rotor radial direction passing through the magnet center, and the variation center direction is , And may be inclined at an inclination angle equal to the inclination angle on the same side with respect to the normal direction.

  According to the first aspect of the present invention, the inclination angle formed by the variation center direction that bisects the variation angle range of the anisotropic segment magnet with respect to the rotor radial direction is set to be equal to or more than half the variation angle range. Therefore, although the actual orientation direction varies, the actual orientation direction can be parallel to the rotor radial direction or inclined to the same side with respect to the rotor radial direction. Therefore, the cogging torque can be reduced. In addition, since the inclination angle is set to an angle that takes into account the variation angle range in advance, the sorting operation in the manufacturing stage as in Patent Document 1 is unnecessary, and the manufacturing cost can be significantly reduced.

According to the invention of claim 2, the normal direction of each mounting surface of the rotor yoke is inclined to the same side with respect to the corresponding rotor radial direction, so that the actual orientation direction of each segment magnet can be easily set to the rotor diameter. It can be inclined parallel to the direction or to the same side with respect to the rotor radial direction.
According to the invention of claim 3, since the variation center direction of each segment magnet is inclined to the same side with respect to the normal direction of the corresponding mounting surface, each mounting surface of the rotor yoke has a corresponding rotor diameter. Even if it is not inclined with respect to the direction, the actual orientation direction of each segment magnet can be easily inclined parallel to the rotor radial direction or to the same side with respect to the rotor radial direction.

It is a mimetic diagram showing a schematic structure of an electric power steering device to which an electric motor of an embodiment of the invention is applied. It is sectional drawing of the electric motor of FIG. It is sectional drawing which follows the III-III line of the electric motor of FIG. It is the elements on larger scale of the rotor of the electric motor of FIG. (A) is the expanded schematic diagram which expand | deployed some rotors so that the rotor circumferential direction of the electric motor of FIG. 3 may become linear form, (b) is the schematic diagram which expand | deployed the rotor of the conventional electric motor. It is. (A), (b) is a figure explaining the relationship between the actual orientation direction of the segment magnet of a rotor, and a rotor radial direction. It is the elements on larger scale of the rotor of the electric motor of another embodiment of this invention. It is sectional drawing of the electric motor of another embodiment of this invention. It is the elements on larger scale of the rotor of the electric motor of FIG. (A) is the expanded schematic diagram which expand | deployed some rotors so that the rotor circumferential direction of the electric motor of FIG. 7 may become linear form, (b) is the schematic diagram which expand | deployed the rotor of the conventional electric motor. It is. (A), (b) is a figure explaining the relationship between the actual orientation direction of the segment magnet of a rotor, and a rotor radial direction. It is the schematic of one manufacturing process in the manufacturing method which manufactures the segment magnet of the rotor of the electric motor of FIG. (A) And (b) is the schematic of the process in another manufacturing method which manufactures the segment magnet of the rotor of the electric motor of FIG. It is a graph which compares the cogging torque of Example 1 and Comparative Example 1 of the present invention.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of an electric power steering apparatus including an electric motor according to an embodiment of the present invention. Referring to FIG. 1, an electric power steering device 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, an intermediate shaft 5 connected to the steering shaft 3 via a universal joint 4, A pinion shaft 7 connected to the intermediate shaft 5 via a universal joint 6, and a rack 9 that meshes with a pinion 8 provided at the tip of the pinion shaft 7 are formed as a steering shaft that extends in the left-right direction of the vehicle. Rack shaft 10.

  Tie rods 11 are connected to both ends of the rack shaft 10, and each tie rod 11 is connected to a corresponding steered wheel 12 via a corresponding knuckle arm (not shown). When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is transmitted to the pinion 8 via the intermediate shaft 5 and the like, and the straight line of the rack shaft 10 along the left-right direction of the vehicle is driven by the pinion 8 and the rack 9. Converted into movement. Thereby, the turning of the steered wheels 12 is achieved.

  The steering shaft 3 has a first steering shaft 13 as an input shaft connected to the steering member 2 and a second steering shaft 14 as an output shaft connected to the universal joint 4. The first and second steering shafts 13 and 14 are coaxially connected to each other via a torsion bar 15. In the vicinity of the torsion bar 15, a torque sensor 16 that detects a relative rotational displacement amount between the first steering shaft 13 and the second steering shaft 14 due to the torsion of the torsion bar 15 is provided.

  A detection signal of the torque sensor 16 is given to an ECU (Electronic Control Unit) 17. The ECU 17 calculates the steering torque applied to the steering member 2 based on the detection signal from the torque sensor 16. Then, based on the calculated steering torque, a vehicle speed detection signal from the vehicle speed sensor 18 and the like, the steering assist electric motor 20 is driven and controlled via the driver 19.

The rotation of the output shaft 21 of the electric motor 20 thus driven is transmitted to the second steering shaft 14 after being decelerated by a reduction gear 22 as a gear device. The power transmitted to the second steering shaft 14 is further transmitted to the steering mechanism A including the rack shaft 10, the tie rod 11, the knuckle arm and the like via the intermediate shaft 5 and the like to assist the driver's steering. .
FIG. 2 is a schematic sectional view of the electric motor 20. 3 is a cross-sectional view taken along line III-III in FIG. 2 and 3, the electric motor 20 is, for example, an inner rotor type three-phase brushless motor. The electric motor 20 includes an output shaft 21, an annular rotor 23 coupled to the output shaft 21 so as to be integrally rotatable, an annular stator 24 surrounding the rotor 23, and a cylindrical shape that houses the rotor 23 and the stator 24. And a housing 25.

The housing 25 includes a housing body 26 having an annular end wall 27 at one end 26 a and having the other end 26 b opened, and a cover 28 that closes the other end of the housing body 26. In the housing 25, for example, a rotation angle sensor (not shown) configured by a resolver is accommodated. A signal from the rotation angle sensor is given to the ECU 17.
One end 21 a of the output shaft 21 is rotatably supported by a bearing 29 held by a cover 28. The other end 21 b of the output shaft 21 is inserted through an insertion hole 27 a provided in the end wall 27 and protrudes out of the housing 25. Although not shown, the other end 21b of the output shaft 21 is coaxially connected to, for example, a worm shaft as a drive gear of the speed reducer 22 via a joint so as to be integrally rotatable. Further, the middle part of the output shaft 21 is rotatably supported by a bearing 30 held on the inner periphery of the insertion hole 27 a of the end wall 27.

  The stator 24 includes a stator core 31 fixed to the inner periphery of the housing main body 26 of the housing 25 and a plurality of coils 32 wound around the stator core 31. As shown in FIG. 3, the stator core 31 includes an annular stator yoke 33, a plurality of teeth 34 projecting radially inward from the stator yoke 33, and a slot 35 formed between the teeth 34. Yes.

As shown in FIG. 2, the rotor 23 includes a cylindrical rotor yoke 36 that is coupled to the output shaft 21 so as to be integrally rotatable, and a segment magnet that is a plurality of anisotropic permanent magnets disposed on the outer periphery 361 of the rotor yoke 36. 37.
As shown in FIG. 3 and FIG. 4 which is an enlarged view, a plurality of mounting surfaces 38 are formed on the outer periphery 361 of the rotor yoke 36. The segment magnets 37 corresponding to the respective attachment surfaces 38 are fixed by being attached using, for example, an adhesive. Each segment magnet 37 is magnetized in a state where the N pole and the S pole are polarized in the orientation direction (magnetic orientation direction). Between the segment magnets 37 and 37 adjacent to each other on the outer periphery 361 of the rotor yoke 36, the N poles and the S poles are arranged so as to be opposite to each other.

  Each mounting surface 38 is a flat surface. Each segment magnet 37 includes a mounted surface 39 that is a flat surface fixed along a corresponding mounting surface 38, and a convex curved surface 40 that faces the teeth 34 with a gap therebetween. That is, in the present embodiment, the cross-sectional shape of each segment magnet 37 is formed such that one side of the rectangle is formed as an outwardly convex arc. By adopting this shape, the cross-sectional area of the segment magnet 37 can be reduced. Therefore, the manufacturing cost can be reduced.

  FIG. 5A is a schematic diagram in which the rotor 23 is developed so that the rotor circumferential direction C1 is linear. In FIG. 5A, the vertical direction corresponds to the rotor radial direction R1, and the horizontal direction corresponds to the rotor circumferential direction C1. As shown in FIG. 5A, each mounting surface 38 is inclined to the same side from a state orthogonal to the rotor radial direction R1, so that the actual orientation direction J1 of each segment magnet 37 becomes the rotor radial direction R1. However, although not shown, it is parallel to the rotor radial direction R1.

FIG. 5B shows a conventional example. In the conventional example shown in FIG. 5B, each mounting surface 138 on the circumferential surface of the rotor yoke 136 is orthogonal to the rotor radial direction R1, so that the actual orientation direction J10 of the segment magnet 137 is the rotor radial direction R1. Are scattered on both sides (left and right in the figure).
Referring again to FIG. 4, the actual orientation direction J1 of each segment magnet 37 varies within a variation angle range δ (for example, 3 to 5 degrees). The variation center direction B1 that bisects the variation angle range δ corresponds to the reference direction of magnetic orientation at the time of manufacture. That is, the actual orientation direction J1 of the manufactured segment magnet 37 varies within a variation angle range δ centered on the variation center direction B1 (corresponding to the reference direction of magnetic orientation at the time of manufacture).

Further, the variation center direction B1 is an inclination corresponding to a half angle (δ / 2, for example, 1.5 to 2.5 degrees) of the variation angle range δ (for example, 3 to 5 degrees) with respect to the rotor radial direction R1. It is inclined at an angle θ (θ = δ / 2).
To achieve this, the normal direction H1 of the corresponding mounting surface 38 that passes through the magnet center CP of each segment magnet 37 (typically, the normal direction H1 coincides with the variation center direction B1) is the magnet center. It is inclined to the same side (same rotational direction) at the inclination angle θ with respect to the rotor radial direction R1 passing through the CP.

Accordingly, the actual orientation direction J1 of each segment magnet 37 is parallel to the rotor radial direction R1 passing through the magnet center CP, or is inclined to the same side (same rotational direction) with respect to the rotor radial direction R1.
According to the present embodiment, the inclination angle θ formed by the variation center direction B1 of the anisotropic segment magnet 37 with respect to the rotor radial direction R1 is set to an angle half of the variation angle range δ (δ / 2) ( That is, θ = δ / 2). Therefore, although the actual orientation direction J1 varies, the actual orientation direction J1 can be parallel to the rotor radial direction R1 or inclined to the same side with respect to the rotor radial direction R1. Thereby, the cogging torque can be significantly reduced.

In addition, since the inclination angle θ in the variation center direction B1 is set to an angle in consideration of the variation angle range δ, the sintered magnetic body in which the orientation direction is inclined in the same direction at the manufacturing stage as in Patent Document 1. There is no need to perform complicated operations to sort out the items. Therefore, the manufacturing cost can be greatly reduced.
Further, the normal direction H1 of each mounting surface 38 of the rotor yoke 36 (usually coincides with the variation center direction B1) is inclined to the same side with respect to the corresponding rotor radial direction R1. Thereby, the actual orientation direction J1 of each segment magnet 37 can be easily and reliably inclined parallel to the rotor radial direction R1 or to the same side with respect to the rotor radial direction R1.

  In the embodiment of FIG. 4, the variation center direction B1 is inclined at an inclination angle θ (θ = δ / 2) corresponding to an angle (δ / 2) that is half of the variation angle range δ with respect to the rotor radial direction R1. However, it is not limited to this. That is, as shown in FIG. 6, the variation center direction B1 is larger than the half angle (δ / 2) of the variation angle range δ with respect to the rotor radial direction R1 passing through the magnet center CP. It may be inclined at> δ / 2).

  In this case, the normal direction H1 of each mounting surface 38 (typically, the normal direction H1 coincides with the variation center direction B1) is the same side (same rotation) as the inclination angle θ with respect to the rotor radial direction R1. Direction). According to the embodiment of FIG. 6, the actual orientation direction J1 of each segment magnet 37 can be surely inclined to the same side with respect to the rotor radial direction R1, and the cogging torque can be significantly reduced. Moreover, the complicated sorting operation as in Patent Document 1 is unnecessary, and the manufacturing cost can be significantly reduced.

  7 is a sectional view of an electric motor according to another embodiment of the present invention, and FIG. 8 is a partially enlarged view of the electric motor of FIG. The present embodiment is different from the embodiment of FIG. 4 as follows. That is, in the embodiment of FIG. 4, the normal direction H1 of the mounting surface 38 is inclined with respect to the rotor radial direction R1, whereas in the embodiment of FIG. 8, the normal direction of the mounting surface 38A. H1A is parallel to the rotor radial direction R1.

  As shown in FIG. 8, also in the rotor 23A of the electric motor 20A of the present embodiment, the actual orientation direction J1 varies within a predetermined variation angle range δ, and the variation center direction B1 passes through the magnet center CP. It is inclined to the same side (same rotational direction) at an inclination angle θ (θ = δ / 2) corresponding to an angle (δ / 2) half of the variation angle range δ with respect to the rotor radial direction R1.

  In order to achieve this, in the present embodiment, the variation center direction B1 of each segment magnet 37A is the normal direction H2 of the mounted surface 39A of each segment magnet 37A (the normal direction H1A of the mounting surface 38A of the rotor yoke 36A). Are inclined at an inclination angle θ on the same side (same rotation direction). That is, the variation center direction B1 (corresponding to the orientation direction at the time of manufacture) is inclined with respect to the mechanical center axis (normal direction H2) of the segment magnet 37A.

On the other hand, the normal direction H2 of the attachment surface 39A (which coincides with the normal direction H1A of the attachment surface 38A) is along the rotor radial direction R1 passing through the magnet center CP.
FIG. 9A shows a schematic diagram in which the rotor 23A is developed so that the rotor circumferential direction C1 is linear. In FIG. 9A, the vertical direction corresponds to the rotor radial direction R1, and the horizontal direction corresponds to the rotor circumferential direction C1. As shown in FIG. 9A, each segment with respect to the normal direction H2 of the mounted surface 39A of each segment magnet 37A (matching the normal direction H1A of the mounting surface 38A) that matches the rotor radial direction R1. The actual orientation direction J1 of the magnet 37A is inclined to the same side with respect to the rotor radial direction R1, or is not shown, but is parallel to the rotor radial direction R1.

FIG. 9B shows a conventional example. In the conventional example shown in FIG. 9B, the actual orientation direction J20 of the segment magnet 237 of the rotor 236 varies on both sides (left and right in the drawing) with respect to the rotor radial direction R1.
Also in the present embodiment, since the actual orientation direction J1 can be inclined parallel to the rotor radial direction R1 or to the same side with respect to the rotor radial direction R1, the cogging torque can be significantly reduced. In addition, since the inclination angle θ in the variation center direction B1 is set to an angle in consideration of the variation angle range δ, the sintered magnetic body in which the orientation direction is inclined in the same direction at the manufacturing stage as in Patent Document 1. There is no need to perform complicated operations to sort out the items. Therefore, the manufacturing cost can be greatly reduced.

However, in the segment magnet 37A, it is necessary to incline the variation center direction B1 of the actual orientation direction J1 with respect to the normal direction H2 of the attachment surface 39A (corresponding to the normal direction H1A of the attachment surface 38A). The following method can be considered as a manufacturing method of such segment magnet 37A.
As shown in FIG. 10, when a powder 50 is obtained by pressing a material powder containing a ferromagnetic material such as neodymium in a pressing direction P1 in a mold (not shown) to form a green compact 50, The magnetic orientation direction K1 is formed and anisotropic by applying a magnetic field by the electromagnetic coil 51 and performing pressure molding in a state where the directions of the crystals are aligned in a certain direction. At this time, the direction of the magnetic field by the electromagnetic coil 51 is inclined with respect to the reference line of the material, and the magnetic orientation direction K1 corresponds to the reference line Q1 (corresponding to the normal direction of the attached surface 39A of the segment magnet 37A finally obtained). ).

  The green compact 50 thus formed is demagnetized and then sintered under high temperature and high pressure conditions to obtain a sintered body. By magnetizing after processing the outer shape of the sintered body or by processing the outer shape of the sintered body after magnetizing the sintered body, a segment magnet magnetized in the magnetic orientation direction K1 is obtained. As shown in FIG. 10, in the case of taking a plurality of pieces, a plurality of segment magnets 37 </ b> A are cut out from the sintered body obtained by sintering the green compact 50.

  Moreover, as a manufacturing method of the segment magnet 37A, the method shown in FIG. 11 can be considered. That is, as shown in FIG. 11 (a), for example, a material powder containing a ferromagnetic material such as neodymium is pressed in a pressing direction P1 in a mold (not shown) to form a green compact 60. When obtaining, the magnetic orientation is applied by the electromagnetic coil 61 from the outside, and the magnetic orientation direction K2 is formed and anisotropically formed by pressure molding in a state where the direction of the crystal is aligned in a certain direction. At this time, the direction of the magnetic field by the electromagnetic coil 61 is parallel to the material reference line Q2, and the magnetic orientation direction K2 is parallel to the reference line Q2.

  The green compact 60 thus formed is demagnetized and then sintered under high temperature and high pressure conditions to obtain a sintered body 62. The sintered body 62 is magnetized, magnetized in the magnetic orientation direction K2, and becomes anisotropic. Thereafter, when the outer shape of the sintered body 62 is processed to obtain the segment magnet 37A, the normal direction H2 of the attachment surface 39A of the segment magnet 37A is relative to the reference line Q2 (corresponding to the magnetic orientation direction K2). The segment magnet 37A is cut out so as to be inclined.

As described above, the segment magnet 37A having the variation center direction B1 inclined with respect to the normal direction H2 of the attached surface 39A shown in FIG. 8 is easily manufactured by the manufacturing method shown in FIGS. be able to.
Note that the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the segment magnet 37; the mounted surface 38; 37A of the 37A and the mounting surface 38; However, instead of a flat surface, a curved surface along the rotor circumferential direction may be used. In addition, various modifications can be made within the scope of the claims.

(Example 1) In the embodiment shown in FIG. 4, the number of anisotropic segment magnets 37 of the rotor 23 is 10 and the number of slots 35 of the stator 24 is 12, and the example of 10 poles and 12 slots is used. 1 was produced. In Example 1, the inclination angle θ formed by the variation center direction B1 of the segment magnet 37 with respect to the rotor radial direction R1 is set to 2 degrees, which is a half angle of the variation angle range δ (δ = 4 degrees). The normal direction H1 of the mounting surface 38 was inclined by an inclination angle θ with respect to the rotor radial direction R1.
(Comparative Example 1)
Comparative Example 1 having 10 poles and 12 slots was produced using a segment magnet of the same production lot as in Example 1. In Comparative Example 1, the normal direction of the mounting surface of the rotor was parallel to the rotor radial direction.
(test)
When cogging torque was measured under the same test conditions using Example 1 and Comparative Example 1, as shown in FIG. 12, the maximum value of the cogging torque of Comparative Example 1 was 17.7 mN · m, and the minimum value was The average value was 1.7 mN · m.

On the other hand, the cogging torque of Example 1 had a maximum value of 4.3 mN · m, a minimum value of 0.6 mN · m, and an average value of 1.9 mN · m.
From the above results, it was proved that the cogging torque can be remarkably reduced in Example 1 as compared with Comparative Example 1, and the variation range of the cogging torque can be remarkably reduced.

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus, 2 ... Steering member, 13 ... 1st steering shaft, 14 ... 2nd steering shaft, 20 ... Electric motor, 21 ... Output shaft, 22 ... Reduction gear, 23; 23A ... Rotor, 24 ... Stator 25 ... Housing, 31 ... Stator core, 32 ... Coil, 33 ... Stator yoke, 34 ... Teeth, 35 ... Slot, 36; 36A ... Rotor yoke, 361 ... Outer periphery, 37; 37A ... Segment magnet, 38; 38A ... Mounting surface, 39; 39A ... surface to be attached, 40 ... convex curved surface, B1 ... variation center direction, C1 ... rotor circumferential direction, C2 ... rotor center, CP ... magnet center, H1; H1A ... normal direction (on the attachment surface), H2 ... Normal direction (of the surface to be mounted), J1 ... Actual orientation direction, R1 ... Rotor radial direction, δ ... Variation angle range, θ ... Inclination angle

Claims (3)

A stator and a rotor,
The rotor includes a cylindrical rotor yoke having a peripheral surface provided with a plurality of mounting surfaces, and a plurality of anisotropic segment magnets respectively fixed to the mounting surfaces.
The actual orientation direction of each segment magnet varies within a predetermined variation angle range, and the actual orientation direction of each segment magnet is parallel to the rotor radial direction passing through the magnet center of each segment magnet, or the rotor The variation center direction that bisects the variation angle range is inclined at an inclination angle that is equal to or greater than half the variation angle range with respect to the rotor radial direction so that the variation angle range is equally divided with respect to the radial direction. Electric motor.   2. The normal direction of the corresponding mounting surface that passes through the magnet center of each of the segment magnets according to claim 1, with an inclination angle equal to the inclination angle on the same side with respect to the rotor radial direction that passes through the magnet center. An inclined electric motor. In claim 1, the normal direction of the corresponding mounting surface passing through the magnet center of each of the segment magnets is along the rotor radial direction passing through the magnet center,
The electric motor in which the variation center direction is inclined at an inclination angle equal to the inclination angle on the same side with respect to the normal direction.

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