Motor

Abstract

A motor (1) includes a shaft (2), a rotor (4), and a stator (3). The rotor (4) has: a yoke (41); and a first magnet (42a) and a second magnet (42b) disposed in the circumferential direction (C), the first magnet (42a) and the second magnet (42b) being present inside the yoke (41), and an end portion (42a1) of the first magnet (42a) on the opposite side of the stator (3) being located on the opposite side of the stator (3) with respect to an end portion (42b1) of the second magnet (42b) on the opposite side of the stator (3) in the radial direction (R).

Description

Technical Field

[0001] The present invention relates to a motor. Background Art

[0002] A so-called Halbach array motor is known in which a plurality of magnets having magnetic fluxes directed in different directions are arranged on the surface of a rotor yoke (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-006545 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, there is room for improvement in the output torque of the motor.

[0008] In view of the above problems, the present invention provides a motor capable of improving output torque.

[0009] Technical means of solving problems

[0010] In order to solve the above-mentioned problems and achieve the purpose, the motor of the present invention includes a shaft, a rotor, and a stator, wherein the rotor has: a yoke; and a first magnet and a second magnet, which are arranged in a circumferential direction, and the first magnet and the second magnet exist inside the yoke, and in the radial direction, the end of the first magnet on the opposite side of the stator is on the opposite side of the stator relative to the end of the second magnet on the opposite side of the stator.

[0011] Through one form, the output torque of the motor can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [ Figure 1 ] Figure 1 It is a plan view of the motor according to the first embodiment.

[0013] [ Figure 2 ] Figure 2 yes Figure 1 A perspective view of the motor is shown.

[0014] [ Figure 3 ] Figure 3 yes Figure 1 A perspective view of a rotor included in the motor is shown.

[0015] [ Figure 4 ] Figure 4 Yes means Figure 3 A perspective view of a portion of a yoke included in the rotor shown.

[0016] [ Figure 5 ] Figure 5 Yes means Figure 1 A plan view of a portion of a motor is shown.

[0017] [ Figure 6 ] Figure 6 Yes means Figure 1 A plan view showing the direction of magnetic flux of a plurality of magnets included in the motor shown.

[0018] [ Figure 7 ] Figure 7 It is a plan view of a motor according to a first modified example of the first embodiment.

[0019] [ Figure 8 ] Figure 8 yes Figure 7 A perspective view of a rotor included in the motor is shown.

[0020] [ Fig. 9 ] Fig. 9 It is a plan view showing a part of a motor according to a second embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, the motor of the embodiment will be described in detail based on the drawings. In addition, the relationship between the dimensions of the components in the drawings, the ratio of the components, etc. may be different from the actual ones. The drawings may also contain parts with different dimensional relationships or ratios.

[0022] Figure 1 It is a plan view of the motor 1 according to the first embodiment. Figure 2 yes Figure 1 A perspective view of the motor 1 is shown. Figure 3 yes Figure 1 The motor 1 is shown in a perspective view of a rotor 4 . Figure 4 Yes means Figure 3 The rotor 4 shown is a perspective view of a portion of a yoke 41 . Figure 5 Yes means Figure 1 A plan view of a portion of the motor 1 is shown. Figure 6 Yes means Figure 1 FIG. 1 is a plan view showing the direction of the magnetic flux of the plurality of magnets 42 included in the motor 1. Figure 1 , Figure 2 , Figure 5 , Figure 6 In FIG. 1 , the × marks on both sides of a tooth 31 b described later indicate windings wound around the tooth 31 b to form the coil 32 .

[0023] [First embodiment]

[0024] In the following description of the motor 1 of the first embodiment, in order to facilitate understanding of the directions, the direction in which the shaft 2 described later extends is called the axial direction A, the direction in which the rotor 4 described later rotates is called the circumferential direction C, and the direction contained in a plane orthogonal to the axial direction A and passing through the axis 2o of the shaft 2 and orthogonal to the circumferential direction C is called the radial direction R.

[0025] First Embodiment Figure 1 The motor 1 shown is an inner rotor type as described later. When viewed from the axial direction A, the stator 3 is located on the outer side in the radial direction R of the rotor 4, and the shaft 2 is located on the inner side in the radial direction R of the rotor 4. In the motor 1 of the present embodiment, the outer side in the radial direction R is referred to as the stator side R1, and the inner side in the radial direction R is referred to as the opposite side R2 of the stator 3. Figures 1 to 6 In the figure, R1 represents the stator side in the radial direction R, and R2 represents the opposite side of the stator 3 in the radial direction R. Figure 3 In the figure, a part of the plurality of magnets 42 described later is omitted to represent the rotor 4. Figure 1 The axis 2 is indicated by an imaginary line in the figure, and is omitted in other drawings.

[0026] The motor 1 of the first embodiment is, for example, an electric motor that converts electric energy from a power source into a driving force for rotating the shaft 2 in the circumferential direction C. Figure 2 As shown, the motor 1 of the present embodiment is a so-called flat motor in which the length in the radial direction R of the stator 3 is longer than the length in the axial direction A of the stator 3 described later. The motor 1 is housed in a frame (not shown), for example.

[0027] For example, Figure 1 As shown, the motor 1 includes a shaft 2, a stator 3, and a rotor 4. The shaft 2 is a so-called rotating shaft, and is formed of, for example, a metal member in a cylindrical shape extending along the axial direction A. The shaft 2 has an axis 2o and is arranged to be rotatable around the axis 2o. The shaft 2 transmits power to the outside by rotating in the circumferential direction C.

[0028] The stator 3 is a portion that generates a force for rotating the rotor 4 in the circumferential direction C. The stator 3 includes a core 31 , an insulator (not shown), and a coil 32 .

[0029] The core 31 is formed by laminating plate-shaped metal members such as silicon steel plates, electromagnetic steel plates, and soft magnetic steel plates in the axial direction A, and has magnetism. In addition, the core 31 of the present embodiment includes a main body 31a and teeth 31b. When viewed from the axial direction A, the main body 31a is formed in an annular shape. The teeth 31b are formed to protrude from the inner peripheral surface of the main body 31a toward the rotor 4 side in the radial direction R. The stator 3 of the present embodiment includes, for example, 18 teeth 31b.

[0030] The insulator is formed of, for example, an insulating resin, and is attached to the surface of the core 31. The coil 32 is formed by winding, for example, a winding on the tooth 31b via the insulator. The winding has a conductive core wire (not shown) and an insulating covering portion (not shown) covering the core wire. The stator 3 of this embodiment has, for example, 18 coils 32.

[0031] The rotor 4 is provided so as to be rotatable about the axis 2o of the shaft 2 as a rotation axis. In the motor 1 of the present embodiment, the shaft 2 and the rotor 4 are formed integrally.

[0032] The rotor 4 is disposed, for example, on the inner side (the shaft 2 side) of the stator 3 in the radial direction R. That is, the motor 1 is an inner rotor type brushless motor in which the rotor 4 is located on the inner side in the radial direction R of the stator 3 .

[0033] like Figure 2 As shown, the rotor 4 includes a yoke 41 and a plurality of magnets 42. The yoke 41 is formed of a magnetic material such as iron.

[0034] The magnet 42 includes, for example, a permanent magnet. The plurality of magnets 42 are arranged, for example, along the circumferential direction C. The plurality of magnets 42 include, for example, 20 first magnets 42 a , 20 second magnets 42 b , and 20 third magnets 42 c .

[0035] The first magnet 42a is a so-called main magnet. The second magnet 42b and the third magnet 42c are so-called auxiliary magnets. In the yoke 41 of this embodiment, the second magnet 42b is arranged on one side of the circumferential direction C of the first magnet 42a, and the third magnet 42c is arranged on the other side of the circumferential direction C of the first magnet 42a.

[0036] The yoke 41 has a function as a path for magnetic flux between the first magnet 42 a and the second magnet 42 b , and has a function as a path for magnetic flux between the first magnet 42 a and the third magnet 42 c .

[0037] like Figure 3 As shown, the yoke 41 has a main body 411, a hole 412, and a frame 413. The main body 411 is formed to extend along the circumferential direction C. That is, the main body 411 is formed in a cylindrical shape. In addition, the yoke 41 includes an outer peripheral surface 41f1 located on the stator side R1 in the radial direction R, and an inner peripheral surface 41f2 located on the opposite side R2 of the stator 3 in the radial direction R.

[0038] A plurality of holes 412 are formed in the main body 411. The plurality of holes 412 are arranged at equal intervals along the circumferential direction C. In addition, the holes 412 are formed to penetrate the main body 411 along the axial direction A. The plurality of holes 412 are arranged at a constant distance from the axis 2o and at constant intervals along the circumferential direction C. In addition, the holes 412 are arranged to be closer to the inner peripheral surface 41f2 than the outer peripheral surface 41f1 of the yoke 41 in the radial direction R.

[0039] Next, the shape of the hole 412 is described. Figure 4 As shown, when viewed from the axial direction A, the hole 412 has three sets of inner surfaces 412f1, 412f2, and 412f3 facing each other. To be more specific, the hole 412 has a pair of first inner surfaces 412f1 facing each other in the circumferential direction C, a pair of second inner surfaces 412f2 facing each other in the circumferential direction C, and a pair of third inner surfaces 412f3 facing each other in the radial direction R. In other words, when viewed from the axial direction A, the hole 412 is formed to be surrounded by the inner surface 412f1, the inner surface 412f2, and the inner surface 412f3 of the wall portion constituting the yoke 41 throughout the circumference. In addition, the first magnet 42a is arranged inside each of the holes 412.

[0040] The pair of first inner surfaces 412f1 are arranged in the hole 412 on the opposite side R2 of the stator 3 (i.e., on the inner peripheral surface 41f2 side of the yoke 41) in the radial direction R. The pair of first inner surfaces 412f1 are arranged parallel to each other. In addition, the pair of first inner surfaces 412f1 are parallel to the center line 1CL described later.

[0041] The pair of second inner surfaces 412f2 are arranged in the hole 412 on the stator side R1 (i.e., on the outer peripheral surface 41f1 side of the yoke 41) in the radial direction R. Moreover, the pair of second inner surfaces 412f2 are arranged to be inclined in a state of being away from each other as they go toward the stator side R1. In addition, the pair of second inner surfaces 412f2 are respectively inclined with respect to the center line 1CL described later.

[0042] One third inner surface 412f32 of the pair of third inner surfaces 412f3 is disposed in the hole 412 on the stator side R1 in the radial direction R. The other third inner surface 412f31 of the pair of third inner surfaces 412f3 is disposed in the hole 412 on the opposite side R2 of the stator 3 in the radial direction R.

[0043] like Figure 5 As shown, in the radial direction R, the boundary 412B between the pair of first inner surfaces 412f1 and the pair of second inner surfaces 412f2 is configured so that the position in the radial direction R becomes substantially the same as the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3. Similarly, the boundary 412B is configured so that the position in the radial direction R becomes substantially the same as the first end 42c1 of the third magnet 42c on the opposite side R2 of the stator 3.

[0044] like Figure 3 As shown, a plurality of frames 413 are formed on the main body 411. The plurality of frames 413 are arranged at a constant interval along the circumferential direction C, for example, at a constant distance from the axis 2o.

[0045] When viewed from the axial direction A, the frame 413 is arranged to surround the hole 412. Figure 5 As shown in FIG. 1 , two frames 413 are arranged on both sides of the hole 412 in the circumferential direction C so that a portion of the hole 412 on the stator side R1 faces a portion of the frame 413 on the opposite side R2 of the stator 3. In other words, when viewed from the axial direction A, as shown in FIG. Figure 4 As shown, the frame 413 is formed to have a pair of first inner surfaces 413f1 facing each other in the circumferential direction C with respect to the wall portion constituting the yoke 41 and a second inner surface 413f2 connecting the pair of first inner surfaces 413f1, and is formed to be surrounded by the pair of first inner surfaces 413f1 and the second inner surface 413f2 on three sides except the stator side R1 in the radial direction R. In addition, the frame 413 is formed to penetrate the main body 411 in the axial direction A.

[0046] The side surface 42b3 of the second magnet 42b or the side surface 42c3 of the third magnet 42c contacts the first inner surface 413f1. The first end 42b1 of the second magnet 42b or the first end 42c1 of the third magnet 42c contacts the second inner surface 413f2.

[0047] The frame 413 has an opening 413o connecting the outside of the yoke 41 and the inside of the frame 413 in the radial direction R. In other words, the frame 413 is arranged so that the opening 413o is formed on the outer peripheral surface 41f1 of the yoke 41. That is, the frame 413 is arranged on the stator side R1 side in the radial direction R of the rotor 4.

[0048] Furthermore, the frame 413 is a portion formed with an opening 413o, and has a pair of protrusions 414 protruding in a manner close to each other inside the frame 413. In other words, the protrusion 414 protrudes from the first inner surface 413f1 toward the inside of the frame 413 along the circumferential direction C. The protrusion 414 protrudes from the main body 411 toward the circumferential direction C. The second magnet 42b and the third magnet 42c are respectively arranged inside the frame 413 (see Figure 5 As described above, the protrusions 414 protrude from the first inner surface 413f1 toward the inside of the frame 413 along the circumferential direction C, and thus the second magnet 42b and the third magnet 42c are restricted from moving toward the stator side R1 in the radial direction R by the protrusions 414. That is, the protrusions 414 function as an engaging portion that engages with the second magnet 42b and the third magnet 42c.

[0049] The first magnet 42a is formed in a rectangular parallelepiped shape, for example. Figure 5As shown, the first magnet 42a has a first end (end) 42a1 on the opposite side R2 of the stator 3 and a second end (end) 42a2 on the stator side R1 in the radial direction R. One of the first end 42a1 and the second end 42a2 is an N pole, and the other is an S pole. In addition, the first magnet 42a has two side surfaces 42a3 facing each other in the circumferential direction C. The two side surfaces 42a3 are parallel to each other and parallel to the center line 1CL described later. The first magnet 42a is arranged to be closer to the inner peripheral surface 41f2 than the outer peripheral surface 41f1 of the yoke 41 in the radial direction R.

[0050] The second magnet 42b is formed, for example, in a rectangular parallelepiped shape. The second magnet 42b has a first end (end) 42b1 on the opposite side R2 of the stator 3 and a second end (end) 42b2 on the stator side R1 in the radial direction R. One of the first end 42b1 and the second end 42b2 is an N pole, and the other is an S pole. In addition, the second magnet 42b has two side surfaces 42b3 facing each other in the circumferential direction C. The two side surfaces 42b3 are parallel to each other and parallel to the center line 1CL described later. Regarding the second magnet 42b of this embodiment, when observed from the axial direction A, the area of ​​the second magnet 42b is larger than the area of ​​the first magnet 42a. The second magnet 42b is configured so that a portion of it is exposed from the opening 413o located on the stator side R1 in the radial direction R.

[0051] The third magnet 42c is formed, for example, in a rectangular parallelepiped shape. The third magnet 42c has a first end (end) 42c1 on the opposite side R2 of the stator 3 and a second end (end) 42c2 on the stator side R1 in the radial direction R. One of the first end 42c1 and the second end 42c2 is an N pole, and the other is an S pole. In addition, the third magnet 42c has two side surfaces 42c3 facing each other in the circumferential direction C. The two side surfaces 42c3 are parallel to each other and parallel to the center line 1CL described later. Regarding the third magnet 42c of the present embodiment, when observed from the axial direction A, the area of ​​the third magnet 42c is larger than the area of ​​the first magnet 42a. The third magnet 42c is configured so that a portion of it is exposed from the opening 413o located on the stator side R1 in the radial direction R.

[0052] Since there are 20 first magnets 42 a , 2nd magnets 42 b , and 3rd magnets 42 c , respectively, the number of magnetic poles of the rotor 4 in the present embodiment is 60 .

[0053] like Figure 1As shown in the figure, the second magnet 42b and the third magnet 42c are arranged to be line symmetrical with respect to the center line 1CL passing through the center of the first magnet 42a in the circumferential direction C and the axis 2o of the shaft 2. In addition, the second magnet 42b is formed in the same shape as the third magnet 42c, for example. Furthermore, the length of the first magnet 42a in the axial direction A, the length of the second magnet 42b in the axial direction A, and the length of the third magnet 42c in the axial direction A are the same. Moreover, the first magnet 42a, the second magnet 42b, and the third magnet 42c are arranged inside the yoke 41.

[0054] Figure 5 The length L1 of the first magnet 42a in the radial direction R is shorter than, for example, the length L20 of the second magnet 42b in the radial direction R. In addition, the length L1 of the first magnet 42a in the radial direction R is shorter than, for example, the length L3 of the third magnet 42c in the radial direction R. Furthermore, the width W1 of the first magnet 42a perpendicular to the radial direction R is narrower than the width W2 of the second magnet 42b perpendicular to the radial direction R. Furthermore, the width W1 of the first magnet 42a perpendicular to the radial direction R is narrower than the width W30 of the third magnet 42c perpendicular to the radial direction R.

[0055] Figure 4 The spacing W4 between the pair of protrusions 414 in the circumferential direction C is narrower than the sum of the width W2 of the second magnet 42b and the width W30 of the third magnet 42c. Therefore, when the rotor 4 is rotated in the circumferential direction C, the pair of protrusions 414 can prevent the second magnet 42b and the third magnet 42c from falling off the yoke 41.

[0056] exist Figure 6 A first gap G1 is formed between the outer peripheral surface 41f1 of the yoke 41 shown and the inner peripheral surface 31bf of the tooth 31b. The width of the first gap G1 in the radial direction R is W11. In addition, a second gap G2 is formed between the second end 42b2 of the stator side R1 of the second magnet 42b and the inner peripheral surface 31bf of the tooth 31b. The width of the second gap G2 in the radial direction R is W21. Furthermore, a third gap G3 is formed between the second end 42c2 of the stator side R1 of the third magnet 42c and the inner peripheral surface 31bf of the tooth 31b. The width of the third gap G3 in the radial direction R is W31.

[0057] The second magnet 42b is arranged so that the width W11 of the first gap G1 and the width W21 of the second gap G2 are equal in the radial direction R. Furthermore, the third magnet 42c is arranged so that the width W11 of the first gap G1 and the width W31 of the third gap G3 are equal in the radial direction R. That is, when the shaft 2 and the rotor 4 are rotated in the circumferential direction C relative to the stationary stator 3, a gap of a constant width is formed between the rotor 4 and the stator 3 in the radial direction R.

[0058] The direction of the magnetic flux of the first magnet 42 a is, for example, along the radial direction R. More specifically, the direction of the magnetic flux of the first magnet 42 a is along the stator side R1 in the radial direction R, or along the opposite side R2 of the stator 3 in the radial direction R.

[0059] The direction of the magnetic flux of the second magnet 42b is, for example, inclined relative to the radial direction R. To be more specific, the direction of the magnetic flux of the second magnet 42b is inclined in a manner gradually approaching the first magnet 42a in the circumferential direction C as it approaches the opposite side R2 of the stator 3, or is inclined in a manner gradually moving away from the first magnet 42a in the circumferential direction C as it approaches the stator side R1.

[0060] The direction of the magnetic flux of the third magnet 42c is, for example, inclined relative to the radial direction R. To be more specific, the direction of the magnetic flux of the third magnet 42c is inclined in a manner gradually approaching the first magnet 42a in the circumferential direction C as it approaches the opposite side R2 of the stator 3, or is inclined in a manner gradually moving away from the first magnet 42a in the circumferential direction C as it approaches the stator side R1.

[0061] In other words, the directions of the magnetic flux of the second magnet 42b and the magnetic flux of the third magnet 42c are inclined so that the mutual distance in the circumferential direction C becomes closer as they approach the opposite side R2 of the stator 3, or are inclined so that the mutual distance in the circumferential direction C becomes farther as they approach the stator side R1.

[0062] In addition, as described above, the directions of the magnetic flux of the first magnet 42a, the direction of the magnetic flux of the second magnet 42b, and the direction of the magnetic flux of the third magnet 42c are different. Therefore, the rotor 4 of the present embodiment is a rotor 4 of a so-called Halbach array in which the first magnet 42a, the second magnet 42b, and the third magnet 42c are arranged in such a manner that the directions of the magnetic fluxes are different from each other.

[0063] In the radial direction R, relative to Figure 5 1 and 2. As shown in FIG. 1 , the first end 42a1 of the first magnet 42a on the opposite side R2 of the stator 3 protrudes from the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3. In other words, in the radial direction R, the first end 42a1 of the first magnet 42a on the opposite side R2 of the stator 3 is located on the opposite side R2 of the stator 3 relative to the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3. That is, the first end 42a1 on the opposite side R2 of the stator 3 in the radial direction R of the first magnet 42a is closer to the inner peripheral surface 41f2 of the yoke 41 than the first end 42b1 on the opposite side R2 of the stator 3 in the radial direction R of the second magnet 42b.

[0064] The second end 42b2 of the second magnet 42b on the stator side R1 protrudes relative to the second end 42a2 of the first magnet 42a on the stator side R1 in the radial direction R. In other words, the second end 42a2 of the first magnet 42a on the stator side R1 is located on the opposite side R2 of the stator 3 relative to the second end 42b2 of the second magnet 42b on the stator side R1 in the radial direction R. That is, the second end 42a2 of the first magnet 42a on the stator side R1 in the radial direction R is away from the outer peripheral surface 41f1 of the yoke 41 by a predetermined distance compared to the second end 42b2 of the second magnet 42b on the stator side R1 in the radial direction R.

[0065] In the radial direction R, the first end 42a1 of the first magnet 42a on the opposite side R2 of the stator 3 protrudes relative to the first end 42c1 of the third magnet 42c on the opposite side R2 of the stator 3. In other words, in the radial direction R, the first end 42a1 of the first magnet 42a on the opposite side R2 of the stator 3 is located on the opposite side R2 of the stator 3 relative to the first end 42c1 of the third magnet 42c on the opposite side R2 of the stator 3. That is, the first end 42a1 on the opposite side R2 of the stator 3 in the radial direction R of the first magnet 42a is closer to the inner peripheral surface 41f2 of the yoke 41 than the first end 42c1 on the opposite side R2 of the stator 3 in the radial direction R of the third magnet 42c.

[0066] The second end 42c2 of the third magnet 42c on the stator side R1 protrudes relative to the second end 42a2 of the first magnet 42a on the stator side R1 in the radial direction R. In other words, the second end 42a2 of the first magnet 42a on the stator side R1 is located on the opposite side R2 of the stator 3 relative to the second end 42c2 of the third magnet 42c on the stator side R1 in the radial direction R. That is, the second end 42a2 of the first magnet 42a on the stator side R1 in the radial direction R is away from the outer peripheral surface 41f1 of the yoke 41 by a predetermined distance compared to the second end 42c2 of the third magnet 42c on the stator side R1 in the radial direction R.

[0067] In the radial direction R, the first end 42a1 of the first magnet 42a and the hole 412 on the opposite side R2 of the stator 3 contacts the third inner surface 412f31 of the hole 412. In addition, in the radial direction R, the second end 42a2 of the first magnet 42a and the hole 412 on the stator side R1 contacts the third inner surface 412f32 of the hole 412.

[0068] The first magnet 42a and the hole 412 are on the opposite side R2 of the stator 3 in the radial direction R, and both side surfaces 42a3 of the first magnet 42a are in contact with the first inner surface 412f1 of the hole 412 in the circumferential direction C. On the other hand, the first magnet 42a and the hole 412 are on the stator side R1 in the radial direction R, and a gap 412s is arranged between both side surfaces 42a3 of the first magnet 42a and the second inner surface 412f2 of the hole 412.

[0069] Air exists in the gap 412s. Moreover, air is a non-magnetic body, and the magnetic permeability of air is smaller than the magnetic permeability of the magnetic material forming the yoke 41. That is, the air existing in the gap 412s functions as a flux barrier, that is, a flux barrier that suppresses the magnetic flux from the side 42b3 of the second magnet 42b toward the side 42a3 of the first magnet 42a, and the magnetic flux from the side 42c3 of the third magnet 42c toward the side 42a3 of the first magnet 42a in the circumferential direction C. Alternatively, the air existing in the gap 412s functions as a flux barrier, that is, a flux barrier that suppresses the magnetic flux from the side 42a3 of the first magnet 42a toward the side 42b3 of the second magnet 42b, and the magnetic flux from the side 42a3 of the first magnet 42a toward the side 42c3 of the third magnet 42c in the circumferential direction C.

[0070] Therefore, in the portion where the gap 412s exists, the magnetic flux from the side of one magnet 42 to the side of the other magnet 42 in the circumferential direction C is suppressed by the air which is a non-magnetic body. As a result, in the portion where the gap 412s exists, the magnetic flux is suppressed by the non-magnetic body between the two side surfaces 42a3 in the circumferential direction C of the first magnet 42a and the two side surfaces 42b3 in the circumferential direction C of the second magnet 42b. Similarly, in the portion where the gap 412s exists, the magnetic flux is suppressed by the non-magnetic body between the two side surfaces 42a3 in the circumferential direction C of the first magnet 42a and the two side surfaces 42c3 in the circumferential direction C of the third magnet 42c.

[0071] On the other hand, in the circumferential direction C, at the portion where the side surfaces 42a3 of the first magnet 42a contact the first inner surface 412f1 of the hole 412, magnetic flux passes between the side surfaces 42a3 of the first magnet 42a and the first end 42c1 of the third magnet 42c.

[0072] The first magnet 42a is formed into a rectangular parallelepiped, and a pair of side surfaces 42a3 facing each other in the circumferential direction C are parallel, and the side surfaces 42a3 are parallel to the center line 1CL. On the other hand, in the hole 412, a pair of second inner surfaces 412f2 facing each other in the circumferential direction C are formed to be inclined away from each other as they approach the stator side R1 in the radial direction R. Moreover, the second inner surface 412f2 of the hole 412 is inclined relative to the center line 1CL. That is, in the rotor 4 of this embodiment, the side surfaces 42a3 of the first magnet 42a are relatively inclined relative to the second inner surface 412f2 of the hole 412.

[0073] When in radial direction R, such as Figure 5As shown in FIG. 1 , when the length from the position of the second end 42a2 of the first magnet 42a on the opposite side R2 of the stator 3 to the position of the second end 42b2 of the second magnet 42b on the opposite side R2 of the stator 3 is set as L2, the rotor 4 of the present embodiment becomes L1 / 2>L2. That is, in the radial direction R, the protrusion amount of the second end 42a2 of the first magnet 42a relative to the second end 42b2 of the second magnet 42b (that is, L2 is the offset amount) is smaller than half of the length L1 of the first magnet 42a in the radial direction R.

[0074] In addition, the surface area of ​​the side surface 42b3 of the second magnet 42b extending in the radial direction R is denoted as S1. Furthermore, the surface area of ​​the surface extending in the circumferential direction C, that is, the surface of the stator side R1 of the yoke 41 in the rotor 4 is denoted as S2. And, when the number of magnetic poles of the rotor 4 (the number of magnetic poles of the rotor 4 in this embodiment is 60) is denoted as P, in the rotor 4 of this embodiment, S1>S2 / P.

[0075] Furthermore, when the surface area of ​​the surface extending in the circumferential direction C, that is, the surface of the first magnet 42 a on the stator side R1 is represented by S3 , in the rotor 4 of the present embodiment, S1 / 2 > S3 .

[0076] When the width of the first magnet 42 a in the circumferential direction C is W1 , the width of the second magnet 42 b in the circumferential direction C is W2 , and the width of the frame 413 in the circumferential direction C is W3 , the rotor 4 of the present embodiment satisfies W2 ≧ W1 > W3 .

[0077] In the rotor 4 of the present embodiment, the first end 42a1 of the first magnet 42a on the opposite side R2 of the stator 3 is located on the opposite side R2 of the stator 3 relative to the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3 in the radial direction R. Therefore, the rotor 4 of the present embodiment can reduce the magnetic flux from the first end 42a1 of the first magnet 42a and the first end 42b1 of the second magnet 42b toward the opposite side R2 of the stator 3 in the radial direction R (in Figure 6 The magnetic flux density indicated by arrows f9 and f10 in the figure is increased, and the magnetic flux in the circumferential direction C from one to the other is increased at the first end 42a1 of the first magnet 42a and the first end 42b1 of the second magnet 42b. Figure 6 As a result, the motor 1 of the present embodiment increases the magnetic flux density (indicated by arrows f2 and f4) from the second end 42a2 of the first magnet 42a and the second end 42b2 of the second magnet 42b toward the stator 3 in the radial direction R. Figure 6 The magnetic flux density (indicated by arrows f3 and f6) can increase the output torque of motor 1.

[0078] In the rotor 4 of the present embodiment, the first end 42a1 of the first magnet 42a on the opposite side R2 of the stator 3 is located on the opposite side R2 of the stator 3 relative to the first end 42c1 of the third magnet 42c on the opposite side R2 of the stator 3 in the radial direction R. Therefore, the rotor 4 of the present embodiment can reduce the magnetic flux from the first end 42a1 of the first magnet 42a and the first end 42c1 of the third magnet 42c toward the opposite side R2 of the stator 3 in the radial direction R (in Figure 6 The magnetic flux density indicated by arrows f8 and f10 in the first magnet 42a and the first end 42c1 of the third magnet 42c is increased from one of them toward the other in the circumferential direction C (in Figure 6 As a result, the motor 1 of the present embodiment increases the magnetic flux density (indicated by arrows f1 and f5) from the second end 42a2 of the first magnet 42a and the second end 42b2 of the third magnet 42c toward the stator 3 in the radial direction R. Figure 6 The magnetic flux density (indicated by arrows f3 and f7) can increase the output torque of motor 1.

[0079] In the rotor 4 of the present embodiment, in the radial direction R, the second end 42a2 of the first magnet 42a on the stator side R1 is located on the opposite side R2 of the stator 3 to the second end 42b2 of the second magnet 42b on the stator side R1.

[0080] In the rotor 4 of the present embodiment, in the radial direction R, the second end 42a2 of the first magnet 42a on the stator side R1 is located on the opposite side R2 of the stator 3 to the second end 42c2 of the third magnet 42c on the stator side R1.

[0081] In the rotor 4 of the present embodiment, the yoke 41 includes a hole 412 and a frame 413 surrounding the hole 412, and a first magnet 42a is present inside the hole 412. In the circumferential direction C, a gap 412s is present between the second inner surface 412f2 of the hole 412 and the side surface 42a3 of the first magnet 42a. In addition, a non-magnetic body having a magnetic permeability smaller than that of the magnetic material forming the yoke 41 exists in the gap 412s. Therefore, in the circumferential direction C, in the portion where the gap 412s exists, the magnetic flux from the side surface 42a3 of the first magnet 42a toward the side surface 42b3 of the second magnet 42b and the side surface 42c3 of the third magnet 42c is suppressed by the non-magnetic body. As a result, the magnetic flux density increases between the first end 42a1 of the first magnet 42a and the first end 42b1 of the second magnet 42b, and between the first end 42a1 of the first magnet 42a and the first end 42c1 of the third magnet 42c. Therefore, the motor 1 of the present embodiment can increase the magnetic flux density from the first magnet 42 a toward the stator 3 .

[0082] In the rotor 4 of the present embodiment, the surface area of ​​the side surface 42b3 of the second magnet 42b extending in the radial direction R is denoted as S1, and the surface area of ​​the surface extending in the circumferential direction C, that is, the surface of the stator side R1 of the yoke 41 in the rotor 4 is denoted as S2. Furthermore, when the number of magnetic poles of the rotor 4 (60 in the rotor 4 of the present embodiment) is denoted as P, S1>S2 / P is satisfied in the rotor 4 of the present embodiment. Therefore, in order to maximize the surface area S1 of the side surface 42b3 of the second magnet 42b, the size L20 of the second magnet 42b in the radial direction R can be extended as much as possible.

[0083] In the rotor 4 of the present embodiment, when the width of the first magnet 42a in the circumferential direction C is set to W1, the width of the second magnet 42b in the circumferential direction C is set to W2, and the width of the frame 413 in the circumferential direction C is set to W3, W2≧W1>W3. Therefore, the rotor 4 of the present embodiment can saturate the magnetic flux between the side surface 42a3 of the first magnet 42a and the side surface 42b3 of the second magnet 42b in the circumferential direction C by narrowing the width W3 of the frame 413. As a result, the motor 1 of the present embodiment can increase the magnetic flux density from the first magnet 42a and the second magnet 42b toward the stator 3 by increasing the magnetic flux density between the first end 42a1 of the first magnet 42a and the first end 42b1 of the second magnet 42b. In addition, by narrowing the width W3 of the frame 413 as much as possible, the size of the yoke 41 in the radial direction R can be reduced.

[0084] In the rotor 4 of the present embodiment, when the width of the first magnet 42a in the circumferential direction C is set to W1, the width of the third magnet 42c in the circumferential direction C is set to W30, and the width of the frame 413 in the circumferential direction C is set to W30, W30≧W1>W3. Therefore, the rotor 4 of the present embodiment can saturate the magnetic flux between the side surface 42a3 of the first magnet 42a and the side surface 42c3 of the third magnet 42c in the circumferential direction C by narrowing the width W3 of the frame 413. As a result, the motor 1 of the present embodiment can increase the magnetic flux density from the first magnet 42a and the third magnet 42c toward the stator 3 by increasing the magnetic flux density between the first end 42a1 of the first magnet 42a and the first end 42c1 of the third magnet 42c. In addition, by narrowing the width W3 of the frame 413 as much as possible, the size of the yoke 41 in the radial direction R can be reduced.

[0085] Furthermore, the stator 3 of the above embodiment has been described as including 18 teeth 31 b. However, the number of teeth 31 b of the stator 3 of the present embodiment is not limited thereto, and can be set to any number.

[0086] In addition, the above-described embodiment has been described in which the stator 3 includes 18 coils 32. However, the number of coils 32 of the stator 3 of the present embodiment is not limited thereto, and can be set to any number.

[0087] Furthermore, the rotor 4 of the above embodiment includes 20 first magnets 42a, 20 second magnets 42b, and 20 third magnets 42c. However, the number of these magnets 42a, 42b, and 42c is not limited thereto and can be set to any number.

[0088] In addition, the following case is described: in the rotor 4 of the above embodiment, the side surface 42a3 of the first magnet 42a is parallel to the center line 1CL, and the second inner surface 412f2 of the hole 412 is inclined with respect to the center line 1CL, so that the first magnet 42a is inclined with respect to the second inner surface 412f2 of the hole 412. However, the rotor 4 of the present embodiment is not limited to this. For example, the side surface 42a3 of the first magnet 42a may be inclined with respect to the center line 1CL, and the second inner surface 412f2 of the hole 412 may be parallel to the center line 1CL, so that both side surfaces 42a3 of the first magnet 42a are inclined with respect to the second inner surface 412f2 of the hole 412. In addition, the side surface 42a3 of the first magnet 42a may be inclined with respect to the center line 1CL, and the second inner surface 412f2 of the hole 412 may be inclined with respect to the center line 1CL, so that both side surfaces 42a3 of the first magnet 42a are inclined with respect to the second inner surface 412f2 of the hole 412.

[0089] Furthermore, in the above embodiment, the rotor 4 includes the rectangular parallelepiped first magnet 42a, the rotor 4 includes the rectangular parallelepiped second magnet 42b, and the rotor 4 includes the rectangular parallelepiped third magnet 42c. However, the shapes of the magnets 42a, 42b, and 42c in this embodiment are not limited thereto, and may be formed in other shapes.

[0090] In the above embodiment, the hole 412 is formed to have three sets of inner surfaces 412f1, 412f3, 412f3 facing each other when viewed from the axial direction A. However, the shape of the hole 412 in this embodiment is not limited thereto, and may be formed in other shapes.

[0091] [First Modification of the First Embodiment]

[0092] Next, use Figure 7 , Figure 8 A motor 1A according to a first modified example of the first embodiment will be described. Figure 7 It is a plan view of a motor 1A according to a first modified example of the first embodiment. Figure 8 yes Figure 7 The shown motor 1A includes a rotor 4A in a perspective view.

[0093] The frame 413 in the yoke 41 of the rotor 4A of this modification is similar to the frame 413 in the yoke 41 of the rotor 4 of the first embodiment. Figure 8 As shown, it has a second inner surface 413f2 orthogonal to the radial direction R. In addition, the rotor 4A of this modified example has a recessed portion 416 formed in the frame 413. Two recessed portions 416 are formed for one frame 413, and two recessed portions 416 are formed on the second inner surface 413f2 constituting the frame 413. To explain more specifically, the recessed portion 416 is formed to extend along the first inner surface 413f1 and in the radial direction R.

[0094] The recessed portion 416 includes a first inner surface 416a located on the opposite side R2 of the stator 3 in the frame 413, and a pair of second inner surfaces 416b located on both sides of the first inner surface 416a in the circumferential direction C and facing each other in the circumferential direction C. Figure 7 As shown in FIG. 1 , such recessed portions 416 are arranged on both sides of the side surface 42a3 of the first magnet 42a in the circumferential direction C. To be more specific, the recessed portions 416 are arranged on both sides of the side surface 42a3 of the first magnet 42a that contacts the second inner surface 412f2 of the hole 412 in the circumferential direction C. In addition, in the circumferential direction C, a portion of the frame 413 exists between the recessed portions 416 and the first magnet 42a.

[0095] In addition, the second magnet 42b and the third magnet 42c are arranged inside the frame 413. Moreover, the length of the recessed portion 416 in the circumferential direction C is shorter than 1 / 2 of the length of the frame 413 in the circumferential direction C. Therefore, in addition, a part of the first end 42b1 of the second magnet 42b and a part of the first end 42c1 of the third magnet 42c are in contact with the second inner surface 413f2 of the frame 413.

[0096] In other words, the yoke 41 of this modified example has a second inner surface 413f2, which is opposite to the surface of the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3 in the radial direction R. In addition, a recess 416 is provided on the second inner surface 413f2 that is opposite to the surface of the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3. Moreover, a gap 416s exists between the surface of the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3 and the recess 416. In addition, the second magnet 42b is described above, but the third magnet 42c is also the same.

[0097] Air exists in the gap 416s. Moreover, air is a non-magnetic body, and the magnetic permeability of air is smaller than the magnetic permeability of the magnetic material forming the yoke 41. That is, the air existing in the gap 416s functions as a magnetic flux barrier that suppresses the magnetic flux from the side 42b3 of the second magnet 42b toward the side 42a3 of the first magnet 42a, and the magnetic flux from the side 42c3 of the third magnet 42c toward the side 42a3 of the first magnet 42a in the circumferential direction C. Alternatively, the air existing in the gap 416s functions as a magnetic flux barrier that suppresses the magnetic flux from the side 42a3 of the first magnet 42a toward the side 42b3 of the second magnet 42b, and the magnetic flux from the side 42a3 of the first magnet 42a toward the side 42c3 of the third magnet 42c in the circumferential direction C.

[0098] In the rotor 4A of the present modification, either the gap 412s or the gap 416s is arranged laterally in the circumferential direction C of the side surface 42a3 of the first magnet 42a.

[0099] In the rotor 4A of this modification, a recess 416 is provided in the yoke 41, and a gap 416s exists between the surface of the first end 42b1 of the second magnet 42b on the opposite side R2 of the stator 3 and the recess 416. In addition, a non-magnetic body having a magnetic permeability smaller than that of the magnetic material forming the yoke 41 exists in the gap 416s. Therefore, in the circumferential direction C, in the portion where the gap 416s exists, the magnetic flux from the side 42a3 of the first magnet 42a toward the side 42b3 of the second magnet 42b and the side 42c3 of the third magnet 42c is suppressed by the non-magnetic body. As a result, the magnetic flux density increases between the first end 42a1 of the first magnet 42a and the first end 42b1 of the second magnet 42b, and between the first end 42a1 of the first magnet 42a and the first end 42c1 of the third magnet 42c. Therefore, the motor 1A of this modification can increase the magnetic flux density from the first magnet 42a toward the stator 3.

[0100] In the rotor 4A of this modification, either the gap 412s or the gap 416s is arranged on the side of the side surface 42a3 of the first magnet 42a in the circumferential direction C. Therefore, the rotor 4A of this modification can reduce the magnetic flux density between the side surface 42a3 of the first magnet 42a and the side surface 412b3 of the second magnet 42b, and the magnetic flux density between the side surface 42a3 of the first magnet 42a and the side surface 412c3 of the third magnet 42b. As a result, the motor 1A of this modification can increase the magnetic flux density from the second end 42a2 of the first magnet 42a, the second end 42b2 of the second magnet 42b, and the second end 42c2 of the third magnet 42c toward the stator 3, thereby improving the output torque of the motor 1A.

[0101] [Second embodiment]

[0102] Next, use Fig. 9 A motor 1B according to the second embodiment will be described. Fig. 9 1 is a plan view showing a part of a motor 1B according to the second embodiment. In the configuration of the motor 1B according to the second embodiment, the same components as those of the motor 1 according to the first embodiment are denoted by the same reference numerals and their description is omitted.

[0103] Regarding the motor 1B of the second embodiment, when viewed from the axial direction A, the stator 3B is located inside the rotor 4 in the radial direction R, and the shaft (not shown) is located inside the rotor 4 in the radial direction R. That is, the motor 1B of the second embodiment is an outer rotor type brushless motor.

[0104] In the motor 1B of the present embodiment, the inner side in the radial direction R is referred to as the stator side R1, and the outer side in the radial direction R is referred to as the opposite side R2 of the stator 3B. Fig. 9 In the figure, R1 denotes the stator side in the radial direction R, and R2 denotes the opposite side of the stator 3B in the radial direction R. In the motor 1B of the present embodiment, the shaft and the rotor 4B (not shown) are formed separately.

[0105] In the motor 1B of this embodiment, with the center line 2CL in the radial direction R of the rotor 4B as a reference, the hole 412, frame 413, first magnet 42a, second magnet 42b, and third magnet 42c are arranged with the outer side and the inner side in the radial direction R opposite to those of the motor 1 in the first embodiment.

[0106] To explain more specifically, the hole 412 is arranged in the radial direction R closer to the outer peripheral surface 41 f 1 than to the inner peripheral surface 41 f 2 of the yoke 41 .

[0107] The frame 413 is disposed so that the opening 413 o is formed in the inner peripheral surface 41 f 2 . That is, the frame 413 is disposed on the stator side R1 side in the radial direction R of the yoke 41 .

[0108] Furthermore, the first magnet 42a is arranged closer to the outer peripheral surface 41f1 of the yoke 41 than the inner peripheral surface 41f2 in the radial direction R. The first magnet 42a has a first end 42a1 arranged on the opposite side R2 of the stator 3B and a second end 42a2 arranged on the stator side R1.

[0109] The second magnet 42b is disposed so as to partially protrude from the opening 413o located on the stator side R1 in the radial direction R. Furthermore, the second magnet 42b has a first end 42b1 disposed on the opposite side R2 of the stator 3B and a second end 42b2 disposed on the stator side R1.

[0110] The third magnet 42c is disposed so as to partially protrude from the opening 413o located on the stator side R1 in the radial direction R. Furthermore, the third magnet 42c has a first end 42c1 disposed on the opposite side R2 of the stator 3B and a second end 42c2 disposed on the stator side R1.

[0111] The motor 1B of the second embodiment can achieve the same functions and effects as those achieved by the motor 1 of the first embodiment by arranging the hole 412 , the frame 413 , the first magnet 42 a , the second magnet 42 b , and the third magnet 42 c as described above.

[0112] The above is an explanation of the embodiments and variations of the motor 1 according to the present invention, but the present invention is not limited to the embodiments, and various changes can be made without departing from the main purpose of the present invention. The present invention also includes a structure formed by appropriately combining the constituent elements of the above-mentioned embodiments or variations. The present invention also includes a structure formed by making various changes without departing from the main purpose, which is clear to those skilled in the art based on the description of the claims.

[0113] Description of Figure Numbers

[0114] 1.1A, 1B: Motor

[0115] 2: Axis

[0116] 3.3B: Stator

[0117] 4, 4A, 4B: Rotor

[0118] 41: Yoke

[0119] 412: Hole

[0120] 412f2: Second inner surface (inner surface)

[0121] 412s: Gap

[0122] 413: Frame

[0123] 413f2: Second inner surface (inner surface)

[0124] 416: concave part

[0125] 42a: First Magnet

[0126] 42a1: First end (end)

[0127] 42a2: Second end (end)

[0128] 42a3: Side

[0129] 42b: Second magnet

[0130] 42b1: First end (end)

[0131] 42b2: Second end (end)

[0132] 42c3: Side

[0133] 42c: Third magnet

[0134] A: Axial

[0135] C: Circumferential

[0136] R: Radial

[0137] R1: Stator side in radial direction

[0138] R2: The opposite side of stator 3 and stator 3B in the radial direction

Claims

1. A motor comprising a shaft, a rotor, and a stator, The rotor has: a magnetic yoke; and The first magnet and the second magnet are arranged in the circumferential direction. The first magnet and the second magnet exist inside the yoke. In the radial direction, an end portion of the first magnet on the opposite side of the stator is located on the opposite side of the stator relative to an end portion of the second magnet on the opposite side of the stator.

2. The motor according to claim 1, wherein: A third magnet is included inside the magnetic yoke, In the circumferential direction, the first magnet and the third magnet are arranged adjacent to each other. In the radial direction, the end of the first magnet on the stator side is located on the opposite side of the stator with respect to the end of the second magnet on the stator side.

3. The motor according to claim 1 or 2, wherein: The yoke includes a hole and a frame surrounding the hole, Inside the hole there is the first magnet, In the circumferential direction, a gap exists between the inner surface of the hole and the side surface of the first magnet.

4. The motor according to claim 3, wherein: The side surface of the first magnet is inclined relative to the inner surface of the hole.

5. The motor according to claim 1 or 2, wherein: The first magnet includes an end portion on the stator side and an end portion on the opposite side of the stator in the radial direction. The second magnet includes an end portion on the stator side and an end portion on the opposite side of the stator in the radial direction. When the size of the first magnet in the radial direction is L1, When the length from the position of the end of the first magnet on the opposite side of the stator to the position of the end of the second magnet on the opposite side of the stator in the radial direction is L2, It becomes L1 / 2>L2.

6. The motor according to claim 1 or 2, wherein: When the surface area of ​​the side surface of the second magnet extending in the radial direction is denoted as S1, The surface area of ​​the surface extending in the circumferential direction, that is, the surface on the stator side of the rotor is denoted as S2. When the number of magnetic poles of the rotor is set to P, It becomes S1>S2 / P.

7. The motor according to claim 1 or 2, wherein: When the surface area of ​​the surface extending in the circumferential direction, that is, the surface of the first magnet on the stator side is denoted as S3, It becomes S1 / 2>S3.

8. The motor according to claim 1 or 2, wherein: The yoke includes a hole and a frame surrounding the hole, Inside the hole there is the first magnet, When the width of the first magnet in the circumferential direction is set to W1, The width of the second magnet in the circumferential direction is set to W2, When the width of the frame in the circumferential direction is set to W3, It becomes W2≧W1>W3.

9. The motor according to claim 1 or 2, wherein: The yoke includes a surface facing a surface of the second magnet on the opposite side of the stator in the radial direction. A recess is provided on the surface of the second magnet that faces the surface on the opposite side of the stator. There is a gap between the surface of the second magnet on the opposite side to the stator and the recessed portion.

10. The motor according to claim 9, wherein: The surface of the second magnet on the opposite side to the stator is in contact with a portion of the surface facing the surface of the second magnet on the opposite side to the stator.

11. The motor according to claim 9, wherein: The yoke includes a hole and a frame surrounding the hole, In the circumferential direction, a portion of the frame is present between the recess and the first magnet.

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