JP2019037033A - Motor device - Google Patents

Abstract

To provide a motor device that can reduce torque ripple.SOLUTION: A motor device includes a motor having a stator 8 and a rotor 9 and a power supply unit for supplying a rectangular wave current of an electrical angle of 120° to a coil 24 of the stator 8, and the rotor 9 includes a plurality of segment type magnets 33A and 33B arranged in an annular shape in the circumferential direction on the outer peripheral surface of a rotor core 32 and magnet holders disposed at both axial ends of the rotor core 32, and the magnets 33A and 33B are provided with a flat portion formed of a flat surface intersecting the radial direction, and the magnet holder has a pressing portion for pressing the axial end of the magnets 33A and 33B, and the pressing portion is provided with a claw 38a for pressing the flat portions of the adjacent magnets 33A and 33B inward in the radial direction, and the claw 38a is formed of a magnetic material.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a motor device.

  Conventionally, a motor as shown in Patent Document 1 below is known. This motor has a stator core and a stator having a plurality of coils wound around the stator core, and a rotor that is disposed in a radial direction with respect to the stator via a gap and is relatively rotatable. In driving this motor, when energizing a plurality of coils, a rectangular wave current may be supplied to each coil for the purpose of obtaining a large output torque.

JP 2004-64857 A

  However, in the conventional motor, when a rectangular wave current is supplied, nonuniformity (torque ripple) occurs in the output torque due to the harmonic component contained in the rectangular wave current, causing vibration and noise. There was.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a motor device capable of reducing torque ripple.

  In order to solve the above problems, a motor device according to the present invention includes a stator core, a stator having a plurality of coils wound around the stator core, and a relative rotation with respect to the stator via a gap in a radial direction. A rotor having a rotor disposed thereon, and a power supply unit that supplies a rectangular wave current having an electrical angle of 120 ° to the plurality of coils, the rotor being fixed to the rotation shaft. A rotor core, a plurality of segment-type magnets arranged in an annular shape on the outer circumferential surface of the rotor core, and arranged at both axial ends of the rotor core to prevent the magnet from falling off the rotor core A flat portion made of a plane intersecting the radial direction at both ends in the circumferential direction of the outer peripheral surface of the magnet. The rudder has a fixed portion fixed to the axial end portion of the rotor core, a pressing portion that presses the axial end portion of the magnet, and a connecting portion that connects the fixing portion and the pressing portion. The holding part of the magnet holder is provided with a claw part that holds the flat part toward the inside in the radial direction across the flat part of the adjacent circumferential end parts of the adjacent magnets. Is made of a magnetic material.

  Thus, the flat part is provided in the both ends of the circumferential direction of the outer peripheral surface of a magnet, and the nail | claw part of the magnet holder arrange | positioned at the flat part of the magnet is formed with the magnetic material. For this reason, part of the magnetic flux generated from the magnet leaks to the claw portion of the magnet holder, so that the magnetic holder does not form a magnetic flux density across the flat portion of the magnet and the inner surface of the stator via the claw portion. It becomes possible to change with respect to the case. Due to this change, the induced voltage generated when the rectangular wave current is supplied to the coil can contain a fifth harmonic having a phase of 0 ° with respect to the primary phase of the induced voltage. For this reason, among the harmonic components contained in the rectangular wave current with an electrical angle of 120 °, it is possible to equalize the content rates of the fifth harmonic and the seventh harmonic with a high content. Therefore, torque ripple of the motor device can be reduced.

  In addition, the sum of the sizes of the flat portions of the adjacent magnets is set in an electrical angle of 70 ° to 100 °.

  In this case, the induced voltage generated when the rectangular wave current is supplied to the coil can contain more fifth-order harmonics having a phase of 0 ° with respect to the primary phase of the induced voltage. For this reason, the torque ripple of a motor apparatus can be reduced much more reliably.

  According to the present invention, torque ripple of the motor device can be reduced.

It is a perspective view of the motor with a reduction gear provided with the motor apparatus which concerns on 1st Embodiment of this invention. It is AA arrow sectional drawing of the motor with a reduction gear shown in FIG. It is sectional drawing seen from the axial direction which shows the relationship between the stator and rotor of the motor apparatus which concern on 1st Embodiment of this invention. It is a perspective view of the rotor in the motor apparatus concerning a 1st embodiment of the present invention. It is a perspective view of the rotor main body shown in FIG. It is a disassembled perspective view of the rotor main body shown in FIG. It is the figure which looked at the combination of the magnet of the rotor main body shown in FIG. 4 from the axial direction. It is the figure which looked at the combination of the rotor core of the rotor main body shown in FIG. 4, a magnet, and one magnet holder from the axial direction. It is the figure seen from the axial direction of the magnet single-piece | unit in the rotor main body shown in FIG. It is a figure which shows the order component contained in the rectangular wave current supplied from the electric power supply part in the motor apparatus shown in FIG. It is a figure which shows the waveform at the time of the 5th high wavelength component being contained in the induced voltage which generate | occur | produces in the motor shown in FIG. It is the figure which expanded the area | region A among the induced voltage waveforms shown in FIG. Among the schematic diagrams showing the relative positions of the stator teeth and the rotor in the circumferential direction in the motor device according to the first embodiment of the present invention, (a) at the start of rotation, (b) the first half of rotation, and (c) the second half of the rotation. FIG. Among the schematic views showing the stator and the rotor in the motor device according to the first embodiment of the present invention, the sum of the sizes in the circumferential direction of the flat portion is (a) electrical angle 70 ° (b) electrical angle 100 ° (c FIG. 4 is a diagram showing an electrical angle of 120 °. It is the figure which compared the order component of the induced voltage which generate | occur | produces in the motor apparatus which concerns on 1st Embodiment of this invention for every sum of the magnitude | size of the circumferential direction of a flat part. It is the figure which compared the result which added the order component shown in FIG. 10, and the order component shown in FIG. 15 for every sum of the magnitude | size of the circumferential direction of a flat part. It is a perspective view of the rotor main body in the motor apparatus which concerns on 2nd Embodiment of this invention.

(First embodiment)
(Motor with reduction gear)
Hereinafter, with reference to FIGS. 1-16, the motor apparatus 2 which concerns on 1st Embodiment of this invention is demonstrated. In the following description, the reduction gear-equipped motor 1 including the motor device 2 will be described.
As shown in FIGS. 1 and 2, the motor 1 with a reduction gear serves as a drive source for electrical components (for example, a wiper, a power window, a sunroof, an electric seat, etc.) mounted on a vehicle, for example.

The motor 1 with a speed reducer includes a motor device 2 and a speed reducer 3 that decelerates and outputs the rotation of the motor device 2. The motor device 2 includes a motor 2A that converts electrical energy into rotational kinetic energy when energized, and a power supply unit 4 that energizes the motor 2A.
In the following description, a direction along the rotation shaft 31 of the motor 2A is referred to as an axial direction, a direction orthogonal to the axial direction is referred to as a radial direction, and a direction around the rotation shaft 31 is referred to as a circumferential direction.

(motor)
The motor 2 </ b> A has a substantially hexagonal outer shape in a plan view from the axial direction, a hexagonal cylindrical stator 8 (see FIG. 3) housed in the motor case 5, and a diameter relative to the stator 8. And a rotor 9 (see FIG. 3) arranged in a direction so as to be relatively rotatable with a gap therebetween. The rotor 9 extends along the axial direction.

(Motor case)
The motor case 5 is formed of a material with excellent heat dissipation, such as aluminum die cast. As shown in FIG. 2, the motor case 5 includes a first motor case 6 and a second motor case 7 that are configured to be separable in the axial direction. The first motor case 6 and the second motor case 7 are each formed in a bottomed hexagonal cylindrical shape, and a motor case 5 having an internal space is formed by fitting the opposed openings 6a and 7a. doing. The first motor case 6 has a bottom portion 10 formed integrally with the gear case 40 of the speed reducer 3. A through-hole 10 a through which the rotation shaft 31 of the rotor 9 can be inserted is formed at a substantially central portion in the radial direction of the bottom 10.

(Stator)
As shown in FIG. 3, the stator 8 includes a stator core 20 and a plurality of coils 24 wound around the stator core 20. The stator core 20 includes a regular hexagonal cylindrical core portion 21 that forms a magnetic path, and six teeth 22 that protrude radially inward from the core portion 21. Each tooth 22 is arranged at the center in the width direction (the center of the length of the hexagonal side) of the flat wall (corresponding to the hexagonal side) between the corners of the regular hexagonal cylindrical core portion 21. Has been.

  The stator core 20 is formed by laminating a plurality of magnetic metal thin plates in the axial direction. The stator core 20 is not limited to the case where a plurality of magnetic metal thin plates are laminated in the axial direction, and may be formed, for example, by press-molding soft magnetic powder. The outer periphery of the core portion 21 of the stator core 20 formed in this way is fixed to the inner periphery of the first motor case 6 and the second motor case 7.

  A resin insulator 23 is attached to each tooth 22 of the stator core 20 so as to cover the periphery of the tooth 22. Each coil 24 is wound around each tooth 22 so as to cover the insulator 23. Each coil 24 generates a magnetic field for rotating the rotor 9 by energization from the power supply unit 4.

(Rotor)
As shown in FIG. 4, the rotor 9 includes a rotating shaft 31 and a rotor body 9 </ b> A that is externally fixed to the rotating shaft 31. As shown in FIG. 5 and FIG. 6, the rotor body 9 </ b> A is arranged in an annular shape in the circumferential direction on the outer circumferential surface of the rotor core 32 and the cylindrical rotor core 32 fixed to the outer circumference of the rotating shaft 31 by press-fitting. The four segment-type magnets 33A, 33B and a pair of magnet holders 34A, 34B disposed on both axial end surfaces of the rotor core 32 for fixing the magnets 33A, 33B are provided.
The pair of magnet holders 34A, 34B prevent the magnets 33A, 33B from falling off the rotor core 32 by sandwiching the magnets 33A, 33B in the axial direction.

(Rotor core)
The rotating shaft 31 shown in FIG. 4 is integrally formed with the worm shaft 44 that constitutes the speed reducer 3.
The rotor core 32 shown in FIG. 6 is formed by laminating a plurality of metal plates in the axial direction. The rotor core 32 is not limited to the case where a plurality of metal plates are laminated in the axial direction, and may be formed, for example, by press-molding soft magnetic powder.

  As shown in FIGS. 4 and 6, a through hole 32 a penetrating in the axial direction is formed at a substantially center in the radial direction of the rotor core 32, and the rotary shaft 31 is press-fitted into the through hole 32 a. Alternatively, the rotary shaft 31 may be inserted into the through hole 32a, and the rotor core 32 may be externally fixed to the rotary shaft 31 using an adhesive or the like.

  The rotor core 32 is formed with a plurality of caulking fixing holes 32b penetrating along the axial direction around the through hole 32a. In the illustrated example, two caulking fixing holes 32b are formed. The caulking fixing hole 32b is used for fixing the rotor core 32 and the magnet holders 34A and 34B.

(magnet)
As shown in FIGS. 7 to 9, the segment type magnets 33 </ b> A and 33 </ b> B are made of, for example, a ferrite magnet, and are formed so that a cross section perpendicular to the axial direction has a fan shape. Here, since there are four magnets 33A, 33B, each is formed in a sector shape with a central angle θ = 90 °. Magnets 33A and 33B may be neodymium magnets.
The magnets 33A and 33B are both magnetized from the arc-shaped inner peripheral surface 33c along the outer peripheral surface 33d, and when arranged in an annular shape as shown in FIG. 7, the magnetic poles of the outer peripheral surface 33d are circumferential. Are set so that they are alternately arranged in reverse polarity. That is, two types of magnets 33A and 33B magnetized to have opposite polarities are prepared, and are alternately arranged on the outer peripheral surface of the rotor core 32 along the circumferential direction as shown in FIG. Therefore, the rotor body 9A having the assembly of the magnets 33A and 33B has four magnetic poles.

  As shown in FIG. 9, the inner peripheral surfaces 33 c of the magnets 33 </ b> A and 33 </ b> B are formed as circular arc surfaces having a radius of curvature r centered on the axial center O of the rotor 9. On the other hand, the curvature radius r1 of the outer peripheral surface 33d is set smaller than the curvature radius r. The center O1 of the radius of curvature r1 is closer to the center point P than the axis center O on the line segment Lpo connecting the axial center O of the rotor 9 and the midpoint P in the circumferential direction of the outer circumferential surface 33d of the magnets 33A and 33B. It is set to a close position.

That is, in the assembled state as the rotor main body 9A, the outer peripheral surface 33d of the magnets 33A and 33B is such that the position of the middle point P in the circumferential direction of the outer peripheral surface 33d of the magnets 33A and 33B is the most radially outward point. Is formed in a circular arc shape.
Therefore, the outermost peripheral points of the magnet holders 34A and 34B (inside the rotational locus of the circumferential center point P of the outer peripheral surface 33d of the magnets 33A and 33B (the rotational locus of the outermost peripheral point of the rotor main body 9A)) The positions of both ends in the width direction of the claw portion 38a to be described later are determined. Thus, an air gap can be formed between the magnets 33A, 33B and the stator 8 while preventing interference between the magnet holders 34A, 34B and the stator 8.

As shown in FIG. 9, flat portions 33 s made of planes intersecting in the radial direction are provided at both ends in the circumferential direction of the outer peripheral surfaces 33 d of the magnets 33 </ b> A and 33 </ b> B. In the illustrated example, the flat portion 33s is orthogonal to the radial direction.
In the present embodiment, as shown in FIG. 8, the sum θ of the circumferential sizes of the flat portions 33s of the adjacent magnets 33A and 33B is set to be 70 ° or more and 120 ° or less in terms of electrical angle. Here, the size in the circumferential direction means a central angle centering on the axial center O of line segments connecting the axial center O of the rotor 9 and both ends in the circumferential direction on the outer surface of the flat portion 33s. Yes.
Both end surfaces 33t in the circumferential direction of the magnets 33A and 33B are formed in a planar shape along the radial direction. For this reason, as shown in FIGS. 7 and 8, when magnets 33A and 33B are arranged in an annular shape, both circumferential end surfaces 33t of adjacent magnets 33A and 33B can be brought into close contact with each other. Misalignment can be prevented.

(Magnet holder)
As shown in FIG. 6, the magnet holders 34 </ b> A and 34 </ b> B are formed by pressing a metal plate. The magnet holders 34A and 34B are made of a magnetic material.
The magnet holders 34 </ b> A and 34 </ b> B include an annular fixed portion 36, a pressing portion 38 that presses the axial ends of the magnets 33 </ b> A and 33 </ b> B, and a connecting portion 37 that connects the fixing portion 36 and the pressing portion 38. Yes. The fixing part 36, the pressing part 38, and the connecting part 37 are integrally formed. In addition, the fixing | fixed part 36, the holding | suppressing part 38, and the connection part 37 may each be formed separately.

The fixed portions 36 are disposed at both axial ends of the rotor core 32. A circular opening 36 a is provided at the center of the fixed part 36, and the diameter of the opening 36 a is set to be slightly larger than the shaft diameter of the rotating shaft 31. The rotary shaft 31 is inserted through the opening 36 a, and the fixed portion 36 is disposed on the axial end surface of the rotor core 32.
A through hole 36 b that communicates with the caulking fixing hole 32 b is formed in the fixing portion 36 at a position corresponding to the caulking fixing hole 32 b of the rotor core 32.

The connecting portion 37 is formed in a belt shape extending from the outer peripheral portion of the fixed portion 36 toward the radially outer side, and is elastically deformable along the axial direction. Moreover, the four connection parts 37 are provided and are arrange | positioned at equal intervals in the circumferential direction.
The pressing portion 38 is provided separately at the outer end portion in the radial direction of each connecting portion 37. A claw portion 38 a extending in the axial direction is provided at each radially outer end portion of the pressing portion 38. As shown in FIG. 8, the claw portion 38 a presses the flat portion 33 s toward the inner side in the radial direction across the flat portion 33 s of the adjacent circumferential end portions of the adjacent magnets 33 </ b> A and 33 </ b> B.

  As shown in FIGS. 5 and 6, caulking pins 30 are respectively inserted into the through holes 36 b of the two magnet holders 34 </ b> A and 34 </ b> B and the caulking fixing holes 32 b of the rotor core 32. The caulking pin 30 engages the flange-shaped head portion 30a with the upper side surface of the magnet holder 34A, and passes the tip 30b side through the through holes 36b of the magnet holders 34A and 34B and the caulking fixing hole 32b of the rotor core 32. Then, the fixing portion 36 is fixed to the rotor core 32 by caulking the tip 30b. In this way, the rotor core 32 and the magnet holders 34A and 34B are integrated.

  At that time, as shown in FIG. 6, among the magnet holders 34A and 34B arranged at both axial ends of the rotor core 32, between one magnet holder 34B and the axial end surfaces of the plurality of magnets 33A and 33B, An annular rubber washer 39 is disposed.

(Decelerator)
As shown in FIGS. 1 and 2, the speed reducer 3 includes a gear case 40 to which a motor case 5 is attached, and a worm speed reduction mechanism 41 that is housed in the gear case 40. The gear case 40 is made of a material with excellent heat dissipation, such as aluminum die cast. The gear case 40 houses a worm reduction mechanism 41 inside.

  Three fixing brackets 54a, 54b, 54c are integrally formed outside the gear case 40. These fixing brackets 54a, 54b and 54c are for fixing the motor 1 with a speed reducer to a vehicle body (not shown) or the like. The gear case 40 has a substantially cylindrical bearing boss 49 protruding therefrom. The bearing boss 49 is for rotatably supporting the output shaft 48 of the worm speed reduction mechanism 41.

  The worm reduction mechanism 41 includes a worm shaft 44 and a worm wheel (not shown) that is screwed to the worm shaft 44. The worm shaft 44 is arranged coaxially with the rotation shaft 31 of the motor 2A. The worm shaft 44 is rotatably supported by bearings 46 and 47 provided on the gear case 40 at both ends. The end of the worm shaft 44 on the motor 2 </ b> A side protrudes to the gear case 40 through the bearing 46. The projecting end portion of the worm shaft 44 and the end portion of the rotating shaft 31 of the motor 2A are connected, and the worm shaft 44 and the rotating shaft 31 are integrally formed.

  An output shaft 48 is connected to a worm wheel (not shown) screwed to the worm shaft 44 at the radial center of the worm wheel. The output shaft 48 is disposed coaxially with the rotation axis direction of the worm wheel, and protrudes to the outside of the gear case 40 via the bearing boss 49 of the gear case 40.

(Power supply unit)
The power supply unit 4 supplies a rectangular wave current having a pulse width of 120 ° to the plurality of coils 24.
As shown in FIG. 2, the power supply unit 4 is disposed in the cover 63 of the motor 1 with a speed reducer together with the motor 2 </ b> A and the speed reducer 3. The power supply unit 4 may be disposed separately from the motor 2A and the speed reducer 3.
The power supply unit 4 includes a control board that controls a current supplied from a battery (not shown) mounted on the vehicle and supplies the current to the plurality of coils 24. This control board is provided with a switching circuit that generates a rectangular wave current having an electrical angle of 120 °.

(Operation of motor with reduction gear)
Next, operation | movement of the motor 1 with a reduction gear is demonstrated.
When electric power is supplied from the power supply unit 4 to each coil 24 of the motor 2 </ b> A, the motor 1 with a speed reducer forms a predetermined magnetic field in the stator 8 (the teeth 22). A magnetic attractive force or a repulsive force is generated between the magnetic field and the magnets 33A and 33B of the rotor 9, and the rotor 9 is continuously rotated. When the rotor 9 rotates, the worm shaft 44 integrated with the rotating shaft 31 rotates, and further the worm wheel screwed to the worm shaft 44 rotates. Then, the output shaft 48 connected to the worm wheel rotates, and a desired electrical component is driven.

  Here, as shown in FIG. 10, the rectangular wave current having an electrical angle of 120 ° contains harmonic components of a plurality of orders. Among these harmonic components, the fifth harmonic component and the seventh harmonic component, which have a particularly high content, are made equal to each other, thereby causing unevenness in the output torque obtained from the motor 2A (torque ripple) ) Can be reduced. Here, in the illustrated example, the difference between the fifth harmonic component and the seventh harmonic component is about 6%.

  For this reason, in the motor apparatus 2 according to the present embodiment, the magnetic flux density over the magnets 33A and 33B and the inner surface of the stator 8 is changed, and the primary phase of the induced voltage is changed as shown in FIGS. On the other hand, attention is focused on including fifth-order harmonics having a phase of 0 °. Hereinafter, this point will be described in detail.

  First, an induced voltage waveform generated until the stator 8 and the rotor 9 (electrical angle 0 °) at the start of rotation shown in FIG. 13A are relatively rotated in the circumferential direction to the position of the electrical angle 10 ° is shown in FIG. The region A1 is shown in FIG. Here, a claw portion 38a made of a magnetic material is disposed outside the flat portion 33s of the magnets 33A and 33B in the radial direction. As a result, of the adjacent magnets 33A and 33B, the magnetic flux from the flat portion 33s of one magnet flows to the flat portion 33s of the other magnet via the claw portion 38a. The magnetic flux density that passes through decreases. For this reason, as shown to area | region A1 of FIG. 12, the induced voltage is smaller than the case where there is no nail | claw part 38a.

  Next, as the first rotation period shown in FIG. 13B, an induced voltage waveform generated until the stator 8 and the rotor 9 are relatively rotated in the circumferential direction from the position of the electrical angle of 10 ° to the position of the electrical angle of 60 °, This is shown in a region A2 shown in FIG. Here, when the outer peripheral surface 33d of the magnets 33A and 33B gradually approaches the inner surface of the tooth 22, the magnetic flux density of the magnetic flux flowing between the magnets 33A and 33B and the tooth 22 increases, and the induced voltage decreases. doing. At this time, the claw portion 38a from which the magnetic flux from the magnets 33A and 33B leaks gradually moves away from the inner surface of the teeth 22, so that the magnetic flux density of the magnetic flux flowing between the magnets 33A and 33B and the teeth 22 is remarkably increased. To do. Thereby, as shown in FIG. 12, the induced voltage is smaller than the case where there is no claw part 38a.

  Finally, as the later stage of rotation shown in FIG. 13C, an induced voltage waveform generated until the stator 8 and the rotor 9 are relatively rotated in the circumferential direction from the position of the electrical angle of 60 ° to the position of the electrical angle of 90 °, This is shown in a region A3 shown in FIG. Here, when the midpoint P on the outer peripheral surface 33d of the magnets 33A and 33B approaches the central portion of the inner surface of the tooth 22 in the circumferential direction, the change in magnetic flux density becomes smaller, and the induced voltage gradually decreases. At this time, the presence of the claw portion 38a reduces the difference in magnetic flux density between the magnetic poles, and the change in the magnetic flux density is reduced and the change in the induced voltage becomes gradual compared to the case without the claw portion 38a. . Thereby, the induced voltage is larger than the case where there is no nail | claw part 38a.

  Thus, the magnetic flux density is changed so that the induced voltage includes the fifth harmonic component by arranging the claw portion 38a formed of the magnetic member on the outer side in the radial direction of the flat portion 33s. Can do. Further, as an optimum condition for including the fifth harmonic component in the induced voltage, when the circumferential size of the teeth 22 is 102.5 in electrical angle, the sum of the circumferential sizes of the flat portion 33s. Has been confirmed to be 70 in electrical angle.

Next, the effect of the motor device 2 will be described.
As shown in FIG. 14, the induced voltage waveform when the 120 ° rectangular wave was energized was evaluated in the case where the sum of the sizes in the circumferential direction of the flat portion 33 s was 70 °, 100 °, and 120 °. As a result, as shown in FIG. 15, it was confirmed that the harmonics of the respective order components show different contents due to the difference in the size of the flat portion 33s in the circumferential direction.

Then, as a result of adding the harmonic component contained in the rectangular wave current having an electrical angle of 120 ° shown in FIG. 10 and the harmonic component contained in the induced voltage shown in FIG. 15, as shown in FIG. In addition, a difference in content ratio between the fifth harmonic component and the seventh harmonic component was confirmed. These were all confirmed to be less than 4%.
Here, as described above, in the harmonic component contained in the rectangular wave current having an electrical angle of 120 °, the difference in content rate between the fifth harmonic component and the seventh harmonic component was about 6%. Compared with this, when the sum of the sizes in the circumferential direction of the flat portion 33 s is 70 °, 100 °, and 120 °, the difference in content ratio between the fifth harmonic component and the seventh harmonic component is small. It was confirmed.

  As described above, according to the motor device 2 according to the present embodiment, the magnet holders 34A and 34B formed of the magnetic material are provided with the flat portions 33s at both ends in the circumferential direction of the outer peripheral surfaces 33d of the magnets 33A and 33B. The claw portion 38a is disposed on the flat portion 33s of the magnets 33A and 33B. For this reason, a part of the magnetic flux generated from the magnets 33A and 33B leaks to the claw portions 38a of the magnet holders 34A and 34B, so that the flat portions 33s of the magnets 33A and 33B and the inner surface of the stator 8 are connected via the claw portions 38a. , The magnetic flux density can be changed with respect to the case where the magnet holders 34A and 34B are not formed of a magnetic material. Due to this change, the induced voltage generated when the rectangular wave current is supplied to the coil 24 can contain the fifth harmonic having a phase of 0 ° with respect to the primary phase of the induced voltage. For this reason, among the harmonic components contained in the rectangular wave current with an electrical angle of 120 °, it is possible to equalize the content rates of the fifth harmonic and the seventh harmonic with a high content. Therefore, torque ripple of the motor device 2 can be reduced.

  Further, the sum of the sizes in the circumferential direction of the flat portions 33s of the adjacent magnets 33A and 33B is set to 70 ° to 100 ° in electrical angle. For this reason, the induced voltage generated when the rectangular wave current is supplied to the coil 24 can contain more fifth-order harmonics having a phase of 0 ° with respect to the primary phase of the induced voltage. Therefore, the torque ripple of the motor apparatus 2 can be reduced more reliably.

(Second Embodiment)
Hereinafter, with reference to FIG. 17, the motor apparatus which concerns on 2nd Embodiment of this invention is demonstrated.
In the present embodiment, only the rotor body 9B having a configuration different from that of the motor device 2 in the first embodiment will be described. Further, the same reference numerals are given to the same configurations as those of the rotor body 9A in the first embodiment, the description thereof is omitted, and only different points will be described.

As shown in FIG. 17, one magnet holder 34 </ b> C is disposed in the rotor body 9 </ b> B in the present embodiment. The claw portion 38b of the pressing portion 38 of the magnet holder 34C extends over the entire area in the axial direction of the magnets 33A and 33B. Therefore, the claw portion 38b presses the flat portion 33s toward the inside in the radial direction over the entire area in the axial direction. The fixed portion 36 and the connecting portion 37 of the magnet holder 34C are disposed at one end portion in the axial direction of the rotor core 32 and the magnets 33A and 33B.
A locking projection 38c extending inward in the radial direction is formed on each end of the claw portion 38a on the other side in the axial direction. The locking projection 38c is locked to the rubber washer 39 from the other side in the axial direction. Thereby, the magnet holder 34C prevents the magnets 33A and 33B from falling off the rotor core 32 by sandwiching the magnets 33A and 33B in the axial direction.

  As described above, according to the motor device according to the present embodiment, the claw portion 38b formed of a magnetic material is disposed over the entire region in the axial direction inside the flat portion 33s in the radial direction. For this reason, a part of the magnetic flux of the magnets 33A and 33B leaks to the claw portion 38b of the magnet holder 34C even more. Thereby, the magnetic flux density straddling the flat portions 33s of the magnets 33A and 33B and the inner surface of the stator 8 via the claw portions 38b can be changed more significantly. Therefore, the torque ripple of the motor device can be effectively reduced.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in each of the above-described embodiments, the magnet holders 34A, 34B, and 34C are integrally formed of a magnetic material. However, the present invention is not limited to such a mode. Of the magnet holders 34A, 34B, and 34C, as long as at least the claw portions 38a and 38b of the pressing portion are formed of a magnetic material, the other portions may be formed of a nonmagnetic material.

  Moreover, in each said embodiment, although the sum of the magnitude | size of each flat part 33s of adjacent magnet 33A, 33B showed the structure set to 70 degrees or more and 120 degrees or less in electrical angle, such a structure was shown. It is not restricted to an aspect. The sum of the sizes of the flat portions 33s of the adjacent magnets 33A and 33B may be less than 70 ° in electrical angle or greater than 120 °.

  In addition, it is possible to appropriately replace the constituent elements in the embodiment with known constituent elements without departing from the spirit of the present invention, and the above-described modified examples may be appropriately combined.

DESCRIPTION OF SYMBOLS 2 Motor apparatus 2A Motor 4 Electric power supply part 8 Stator 9 Rotor 20 Stator core 24 Coil 31 Rotating shaft 32 Rotor core 33A, 33B Magnet 33s Flat part 34A, 34B, 34C Magnet holder 36 Fixed part 37 Connection part 38 Holding part 38a Claw part

Claims (2)

A stator core, and a stator having a plurality of coils wound around the stator core;
A rotor having a rotor arranged relative to the stator so as to be relatively rotatable with a gap in a radial direction;
A power supply unit that supplies a rectangular wave current having an electrical angle of 120 ° to the plurality of coils,
The rotor is
A rotation axis;
A rotor core fixed to the rotating shaft;
A plurality of segment-type magnets arranged in an annular shape on the outer peripheral surface of the rotor core in a circumferential direction;
A magnet holder that is disposed at both axial ends of the rotor core and prevents the magnet from falling off the rotor core;
At both ends in the circumferential direction of the outer peripheral surface of the magnet, flat portions made of planes intersecting with the radial direction are provided,
The magnet holder is
A fixed portion fixed to an axial end portion of the rotor core;
A holding part for holding the axial end of the magnet;
A connecting portion that connects the fixing portion and the pressing portion;
The holding part of the magnet holder is provided with a claw part that holds the flat part toward the inner side in the radial direction across the flat part of the adjacent circumferential end parts of the magnets,
The claw portion is formed of a magnetic material.   2. The motor device according to claim 1, wherein the sum of the sizes of the flat portions of the adjacent magnets is set to an electrical angle of 70 ° or more and 120 ° or less.

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