JP5111863B2 - Axial gap type motor and electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress generation of an unnecessary vibration applying force occurring together with generation of a cogging torque. <P>SOLUTION: The motor 80, which generates auxiliary torque for assisting a steering torque in a motor-driven power steering device, is constituted of a rotor 83 rotatable around a rotary shaft O and of stators 84, 84 placed opposite to the rotor 83 in the rotary shaft O direction. The rotor 83 includes main magnet parts 90 of eight poles, and the main magnet parts 90 include main permanent magnet pieces with their magnetized direction in the rotary shaft 0 direction. A pair of stators 84, 84, which are placed opposite to each other in the rotary shaft O direction and hold the rotor 83 on both sides in the rotary shaft O direction, each includes teeth 84b of nine poles. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an axial gap type motor and an electric power steering apparatus.

2. Description of the Related Art Conventionally, in an electric power steering device that applies a steering assist force to a steering mechanism by driving a motor according to a steering input by a driver, for example, the motor There is known an electric power steering device in which a stator having a 9-pole electric coil in the circumferential direction and a rotor having an 8-pole permanent magnet in the circumferential direction (see, for example, Patent Document 1).
JP 2005-33924 A

  However, in the electric power steering device according to the above prior art, a relatively large radial excitation force (radial excitation force) is generated during rotation of the motor, and unnecessary vibration is generated in the radial direction. A problem arises that the user feels uncomfortable with the operation of the steering mechanism.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an axial gap type motor and an electric power steering apparatus capable of suppressing the generation of cogging torque and unnecessary excitation force.

In order to solve the above-described problems and achieve the object, an axial gap motor according to a first aspect of the present invention includes a rotor that can rotate around a rotation axis (for example, the rotor 83 in the embodiment), a rotation axially oppositely disposed stator to the rotor (e.g., the stator 84 in the embodiment) an axial gap motor and a said rotor, each four-pole arranged alternately in the circumferential direction main A magnet part (for example, a magnet pole part 90 in the embodiment) and a magnetic material pole part (for example, the magnetic material pole part 83b in the embodiment), and the magnetic material pole part includes the main magnet part and It has the same shape and includes a pole portion through portion (for example, a pole portion through hole 86 in the embodiment) that penetrates in the direction of the rotation axis, and the main magnet portion has a main magnetization direction that is the rotation axis direction. Permanent magnet piece (for example, the permanent magnet in the embodiment) A pair of first stators (for example, a stator 84 in the embodiment) and a second one that are opposed to each other in the rotation axis direction and sandwich the rotor from both sides in the rotation axis direction. A stator (for example, the stator 84 in the embodiment) is provided, and each of the first stator and the second stator has nine pole teeth (for example, the teeth 84b in the embodiment).

An axial gap type motor according to the second aspect of the present invention includes a rotor (for example, the rotor 83 in the embodiment) that can rotate around a rotation axis, and a stator ( For example, it is an axial gap type motor provided with the stator 84 in embodiment, Comprising: The said rotor is each 5 pole main magnet part (for example, magnet pole in embodiment) arrange | positioned alternately in the circumferential direction. Part 90) and a magnetic material pole part (for example, the magnetic material pole part 83b in the embodiment), and the magnetic material pole part has the same shape as the main magnet part and penetrates in the rotation axis direction. A main permanent magnet piece (for example, permanent in the embodiment ) having a pole portion through portion (for example, the pole through hole 86 in the embodiment), and the main magnet portion having a magnetization direction in the rotation axis direction. Magnet piece 83a), the stator being A pair of first stators (for example, the stator 84 in the embodiment) and second stators (for example, the stator 84 in the embodiment) that are opposed to each other in the rotation axis direction and sandwich the rotor from both sides in the rotation axis direction. ), And each of the first stator and the second stator includes 12-pole teeth (for example, the teeth 84b in the embodiment).

An axial gap type motor according to a third aspect of the present invention includes a rotor (for example, the rotor 83 in the embodiment) that can rotate around a rotation axis, and a stator ( For example, it is an axial gap type motor provided with the stator 84 in embodiment, Comprising: The said rotor is each 7 pole main magnet part (for example, magnet pole in embodiment) arrange | positioned alternately in the circumferential direction. Part 90) and a magnetic material pole part (for example, the magnetic material pole part 83b in the embodiment), and the magnetic material pole part has the same shape as the main magnet part and penetrates in the rotation axis direction. A main permanent magnet piece (for example, permanent in the embodiment ) having a pole portion through portion (for example, the pole through hole 86 in the embodiment), and the main magnet portion having a magnetization direction in the rotation axis direction. Magnet piece 83a), the stator being A pair of first stators (for example, the stator 84 in the embodiment) and second stators (for example, the stator 84 in the embodiment) that are opposed to each other in the rotation axis direction and sandwich the rotor from both sides in the rotation axis direction. ), And each of the first stator and the second stator includes 12-pole teeth (for example, the teeth 84b in the embodiment).

  Furthermore, the axial gap type motor according to the fourth aspect of the present invention is such that the magnetization direction is a direction perpendicular to the rotational axis direction and the radial direction, and the main permanent magnet piece is in the vicinity of both ends in the circumferential direction. The first sub permanent magnet piece (for example, the sub permanent magnet piece 91a in the embodiment) arranged at a position shifted to one side in the rotation axis direction from the arrangement position of the permanent magnet piece and the position shifted to the other side. A secondary magnet part (for example, the secondary magnet part 91 in the embodiment) including the second secondary permanent magnet piece (for example, the secondary permanent magnet piece 91a in the embodiment) arranged is provided.

  An electric power steering apparatus according to a fifth aspect of the present invention provides an axial gap motor (for example, the motor 80 in the embodiment) according to any one of the first to fourth aspects, and a steering torque. Steering torque detection means for detecting (for example, the steering torque sensor 70 in the embodiment) and driving control of the axial gap type motor according to the steering torque detected by the steering torque detection means, and the steering torque And a control means (for example, the control means 78 in the embodiment) for generating an auxiliary torque from the axial gap type motor.

According to the axial gap type motor according to the first aspect of the present invention, for each of the nine poles (9) teeth of the first stator and the second stator, By providing a rotor having each of four poles (four pieces) of main magnet portions and magnetic material pole portions, it is possible to suppress the occurrence of cogging torque.
In addition, the rotor is provided with four (four) main magnet portions and magnetic material pole portions in place of the eight pole (eight) main magnet portions, thereby maintaining the number of pole pairs unchanged. The amount of permanent magnets can be reduced, and a pair of first and second pairs can be provided by providing pole portions penetrating portions made of penetrating holes or slits penetrating in the direction parallel to the rotation axis direction in the magnetic material pole portion. A magnetic path penetrating the magnetic material pole portion can be formed between the stators. As a result, a desired magnetic directionality can be imparted to the current magnetic flux generated by the stator windings of each stator, the torque that can be output from the axial gap motor can be increased, and a pair of first and first The current magnetic flux waveform shaping by the stator windings of the pair of first and second stators can be performed so as to suppress a sudden change in the magnetic resistance between the two stators, and the torque ripple and the current magnetic flux waveform Generation of higher harmonics can be suppressed and iron loss can be reduced.
In addition, the pair of first and second stators sandwiching the rotor from both sides in the direction of the rotation axis is energized and controlled so that the field magnetic flux generated by the main permanent magnet piece of the rotor is swept between the first and second stators. Accordingly, the axial direction excitation force caused by the first stator and the axial direction excitation force caused by the second stator are offset, and an outputable torque is generated while suppressing generation of unnecessary excitation force. Can be increased.

Further, according to the axial gap type motor according to the second aspect of the present invention, 10 poles (10 pieces) of the main magnet portion with respect to each 12 poles (12 pieces) of the first stator and the second stator, Or by providing the rotor which comprises each 5 poles (5 pieces) main magnet part and magnetic material pole part, generation | occurrence | production of cogging torque can be suppressed.
Further, the rotor is provided with five (5) main magnet portions and magnetic material pole portions in place of the 10 pole (10 pieces) main magnet portions, thereby maintaining the number of pole pairs unchanged. The amount of permanent magnets can be reduced, and a pair of first and second pairs can be provided by providing pole portions penetrating portions made of penetrating holes or slits penetrating in the direction parallel to the rotation axis direction in the magnetic material pole portion. A magnetic path penetrating the magnetic material pole portion can be formed between the stators. As a result, a desired magnetic directionality can be imparted to the current magnetic flux generated by the stator windings of each stator, the torque that can be output from the axial gap motor can be increased, and a pair of first and first The current magnetic flux waveform shaping by the stator windings of the pair of first and second stators can be performed so as to suppress a sudden change in the magnetic resistance between the two stators, and the torque ripple and the current magnetic flux waveform Generation of higher harmonics can be suppressed and iron loss can be reduced.
In addition, the pair of first and second stators sandwiching the rotor from both sides in the direction of the rotation axis is energized and controlled so that the field magnetic flux generated by the main permanent magnet piece of the rotor is swept between the first and second stators. Accordingly, the axial direction excitation force caused by the first stator and the axial direction excitation force caused by the second stator are offset, and an outputable torque is generated while suppressing generation of unnecessary excitation force. Can be increased.

Further, according to the axial gap type motor according to the third aspect of the present invention, for each of the 12 poles (12 pieces) teeth of the first stator and the second stator, 14 poles (14 pieces) of the main magnet portion, Alternatively, the occurrence of cogging torque can be suppressed by including a rotor having each of seven poles (seven) main magnet portions and magnetic material pole portions.
In addition, the rotor is provided with 7 poles (7 pieces) of main magnet portions and magnetic material pole portions instead of 14 poles (14 pieces) of the main magnet portions, so that the number of pole pairs is maintained unchanged. The amount of permanent magnets can be reduced, and a pair of first and second pairs can be provided by providing pole portions penetrating portions made of penetrating holes or slits penetrating in the direction parallel to the rotation axis direction in the magnetic material pole portion. A magnetic path penetrating the magnetic material pole portion can be formed between the stators. As a result, a desired magnetic directionality can be imparted to the current magnetic flux generated by the stator windings of each stator, the torque that can be output from the axial gap motor can be increased, and a pair of first and first The current magnetic flux waveform shaping by the stator windings of the pair of first and second stators can be performed so as to suppress a sudden change in the magnetic resistance between the two stators, and the torque ripple and the current magnetic flux waveform Generation of higher harmonics can be suppressed and iron loss can be reduced.
In addition, the pair of first and second stators sandwiching the rotor from both sides in the direction of the rotation axis is energized and controlled so that the field magnetic flux generated by the main permanent magnet piece of the rotor is swept between the first and second stators. Accordingly, the axial direction excitation force caused by the first stator and the axial direction excitation force caused by the second stator are offset, and an outputable torque is generated while suppressing generation of unnecessary excitation force. Can be increased.

  Furthermore, according to the axial gap type motor according to the fourth aspect of the present invention, the first sub permanent magnet magnetized in the direction perpendicular to the magnetization direction of the main permanent magnet piece in the vicinity of both ends in the circumferential direction of the main permanent magnet piece. By providing the piece and the second sub-permanent magnet piece, the magnetic flux of the main permanent magnet piece, the first sub-permanent magnet piece, and the second sub-permanent magnet piece can be converged by the magnetic flux lens effect by the so-called Halbach arrangement of the permanent magnet. The amount of magnetic flux interlinking with the stator winding of each stator can be increased.

  Further, according to the electric power steering apparatus of the fifth aspect of the present invention, the torque that is relatively low vibration in which the generation of the cogging torque and the exciting force in the axial direction is suppressed and that can be output is increased. With the relatively high torque axial gap motor that has been made, it is possible to output an appropriate auxiliary torque with respect to the steering torque, while preventing the driver from complicating the configuration of the axial gap motor. It is possible to prevent the operator from feeling uncomfortable with the operation of the steering mechanism.

Hereinafter, an embodiment of a motor of the present invention will be described with reference to the accompanying drawings.
The motor 80 according to the present embodiment is mounted on the electric power steering apparatus 10 as shown in FIG.
This electric power steering apparatus 10 includes a steering mechanism 23 and an auxiliary torque mechanism 24 that applies an auxiliary torque to the steering mechanism 23 in a steering system 22 from the steering handle 11 of the vehicle to the steering wheels (wheels) 21 and 21. ing.

  The steering mechanism 23 includes a rack and pinion mechanism 31, and a pinion shaft 32 of the rack and pinion mechanism 31 is connected to the steering handle 11 via the steering shaft 12 and the universal shaft joints 13 and 13. A rack shaft 34 of the rack and pinion mechanism 31 is connected to left and right steering wheels (wheels) 21 and 21 via left and right ball joints 36 and 36 and left and right tie rods 37 and 37.

The rack and pinion mechanism 31 includes a pinion shaft 32 having a pinion 33 and a rack shaft 34 having a rack 35, and the pinion 33 and the rack 35 are meshed with each other.
Steering torque by the driver's steering input input from the steering handle 11 is transmitted to the left and right steering wheels 21, 21 via the rack and pinion mechanism 31 and the left and right tie rods 37, 37.

  The auxiliary torque mechanism 24 is controlled based on a detection signal of the steering torque sensor 70 such as a magnetostrictive torque sensor, that is, a detection signal of the steering torque sensor 70 with respect to the steering torque of the steering system 22 input from the steering handle 11 by the driver. A control signal is generated in the means 78, and based on this control signal, an auxiliary torque corresponding to the steering torque is generated from the motor 80, and this auxiliary torque is transmitted to the pinion shaft 32 via the torque limiter 110 and the gear type reduction mechanism 120. To do.

  In other words, the electric power steering apparatus 10 transmits the steering torque input from the steering handle 11 to the pinion shaft 32 of the rack and pinion mechanism 31 and transmits the auxiliary torque generated from the motor 80 according to the steering torque to the gear-type reduction mechanism. This is transmitted to the pinion shaft 32 via 120, and the steering wheels 21 and 21 are steered by the rack and pinion mechanism 31. Therefore, the steered wheels 21 and 21 are steered by the composite torque obtained by adding the assist torque of the motor 80 to the steering torque of the driver.

For example, as shown in FIG. 2, the electric power steering apparatus 10 accommodates a rack shaft 34 in a housing 41 extending in the vehicle width direction (that is, the left-right direction in FIG. 2) so as to be slidable in the longitudinal direction of the shaft.
The rack shaft 34 includes ball joints 36 and 36 that are screwed to both ends in the longitudinal direction protruding from the housing 41, and left and right tie rods 37 and 37 that are connected to the ball joints 36 and 36. Brackets 42 and 42 attached to a vehicle body (not shown) and dust seal boots 44 and 44 are provided.

  For example, as shown in FIG. 3, the electric power steering apparatus 10 includes a rack and pinion mechanism 31 housed in a housing 41, a steering torque sensor 70, a torque limiter 110, and a gear-type reduction mechanism 120. The upper opening of the housing 41 is closed by a lid 45. The steering torque sensor 70 is attached to the housing 41 or the lid 45.

  The housing 41 rotatably supports the lower end portion and the longitudinal center portion of the pinion shaft 32 via two upper and lower bearings 51 and 52, and includes a rack guide 60, a lid mounting bolt 53, and a retaining ring 54. .

  The pinion shaft 32 includes a pinion 33 integrally formed at a lower portion, and further includes a screw portion 55 formed at a lower end portion. An upper end portion of the pinion shaft 32 protrudes outward from the lid 45. The movement of the pinion shaft 32 in the axial longitudinal direction (axial direction) is restricted by a nut 56 that is screwed onto the screw portion 55. The pinion shaft 32 includes a cap nut 57, an oil seal 58, and a spacer 59.

  The rack guide 60 includes a guide portion 61 that comes into contact with the rack shaft 34 via a contact member 64, an adjustment bolt 63 that presses the guide portion 61 via a compression spring 62, and a lock nut 65. The screwed adjustment bolt 63 presses the guide portion 61 via the compression spring 62, and the guide portion 61 applies a preload to the rack 35 and presses the rack 35 against the pinion 33.

  For example, as shown in FIG. 4, the motor 80 is attached to the side of the housing 41 with a bolt, a lid 81 that closes the side opening of the housing 41, and a bottomed cylindrical motor attached to the lid 81 with a bolt. The case 82 and a substantially annular rotor 83 provided to be rotatable around the rotation axis O are disposed so as to sandwich the rotor 83 from both sides in the direction of the rotation axis O, and a rotating magnetic field that rotates the rotor 83 is generated. An axial gap type motor including a pair of stators 84, 84, wherein the pair of stators 84, 84 are fitted in a motor case 82, and the inner periphery of the rotor 83 is coaxial with the rotary shaft O. A disposed motor shaft (output shaft) 87 is fitted, and a phase detection sensor 101 that detects the phase of the rotor 83 is provided.

  The lid 81 and the motor case 82 of the motor 80 support the motor shaft 87 rotatably via two bearings 88 and 89. The phase detection sensor 101 includes a laminated core rotor 102 attached to the motor shaft 87 and a detection element 103 that magnetically detects the phase of the laminated core rotor 102, and is covered with a cover 106.

In the torque limiter 110, a male tapered inner member 111 serrated to the motor shaft 87 of the motor 80 is fitted to a female tapered (cup-shaped) outer member 112 serrated to a worm shaft 121 described later. A torque limiting mechanism is provided.
The inner member 111 is fitted to the inner peripheral portion of the outer member 112, and the nut 114 screwed to the inner peripheral surface at the base end portion of the outer member 112 is attached to the base end portion of the inner member 111 via the disc spring 113. The inner member 111 is pressed against the base end portion of the outer member 112, and the outer peripheral surface of the inner member 111 is in contact with the inner peripheral surface of the outer member 112 with a predetermined frictional force. For this reason, when a large torque exceeding a predetermined friction force acts on the torque limiter 110, slip occurs between the outer peripheral surface of the inner member 111 and the inner peripheral surface of the outer member 112, and the motor 80 moves to the gear-type reduction mechanism 120. The transmitted auxiliary torque is regulated. This prevents an excessive torque from being generated in the motor 80 and further prevents an excessive torque from being transmitted to the load side. A retaining ring 115 is attached to the worm shaft 121 coupled to the outer member 112.

  The gear type reduction mechanism 120 is a torque transmission means for transmitting the auxiliary torque generated from the motor 80 to the pinion shaft 32, and includes a worm gear mechanism. For example, the gear reduction mechanism 120 includes a worm shaft 121 connected to the motor shaft 87 of the motor 80 via the torque limiter 110, a worm 122 formed on the worm shaft 121, and a worm wheel connected to the pinion shaft 32. 123.

  The advance angle of the teeth of the worm 122 and the worm wheel 123 is set to be slightly larger than the friction angle. When the motor 80 is stopped, the motor shaft 87 of the motor 80 is sequentially moved to the worm wheel 123, the worm 122, The rotation is enabled by the steering torque of the pinion shaft 32 that transmits the worm shaft 121 and the torque limiter 110.

The worm shaft 121 is disposed coaxially with the motor shaft 87 and is rotatably supported by the housing 41 via two bearings 124 and 125. Of the two bearings 124 and 125 fitted to the housing 41, the first bearing 124 is restricted from moving in the axial longitudinal direction by the retaining ring 129, and the second bearing 125 can be moved in the axial longitudinal direction. Has been.
The end surface of the outer ring of the second bearing 125 is pressed toward the motor shaft 87 by the lock nut 128 and the adjustment bolt 127 via the leaf spring 126.

  For example, as shown in FIG. 5, each stator 84 of the motor 80 has a substantially annular plate-shaped yoke portion 84 a and a yoke portion 84 a facing the rotor 83 on a facing surface from a position spaced apart in the circumferential direction. A plurality of (for example, nine) teeth 84b,..., 84b projecting toward the rotor 83 along the direction of the rotation axis O and extending in the radial direction, and stator windings mounted between appropriate teeth 92, 92 ( (Not shown).

Of the two stators 84, 84, one stator 84 has teeth 84 b,... Corresponding to three types of 3N main poles (for example, N = 3) composed of, for example, U ⁺ , V ⁺ , W ⁺ poles. comprising a 84b, the other stator 84, for example ^{U -, V -,} W - and includes teeth 84b corresponding to the three kinds of 3N number of main poles made of poles (e.g., N = 3), ..., the 84b . The U ⁻ , V ⁻ , and W ⁻ poles of the other stator 84 face each other in the direction of the rotation axis O with respect to the U ⁺ , V ⁺ , and W ⁺ poles of the one stator 84. The energized state of the teeth 84b and the teeth 84b of the other stator 84 is set so as to be reversed by an electrical angle.

  The rotor 83 includes a plurality of (for example, eight) magnet pole portions 90,..., 90a and a rotor frame 85 made of a non-magnetic material. Are accommodated in the rotor frame 85.

For example, as shown in FIG. 6, the rotor frame 85 includes an inner peripheral cylindrical portion 85 b and an outer peripheral cylindrical shape connected by a plurality of radial ribs 85 a, 85 a arranged at predetermined intervals in the circumferential direction. A portion 85c and a connecting portion 85d that is formed in an annular plate shape that protrudes inward from the inner peripheral surface of the inner peripheral cylindrical portion 85b and that is connected to the motor shaft (output shaft) 87. Has been.
And the magnet pole part 83a accommodated in the rotor frame 85 is sandwiched by the inner peripheral side cylindrical part 85b and the outer peripheral side cylindrical part 85c from both sides in the radial direction, and circumferentially through the radial rib 85a. Are arranged adjacent to each other.

The magnet pole portion 90 is a substantially sector plate-shaped permanent magnet piece 83a magnetized in the thickness direction (that is, the direction of the rotation axis O), and each permanent magnet piece of the magnet pole portions 90 and 90 adjacent in the circumferential direction. 83a and 83a are set so that the magnetization directions are different from each other.
In other words, the magnet pole portion 90 made of the permanent magnet piece 83a whose one side in the direction of the rotation axis O is N pole has the magnet pole portion 90 made of the permanent magnet piece 83a whose one side in the direction of the rotation axis O is S pole. Adjacent in the circumferential direction.

As described above, according to the motor 80 according to the present embodiment, eight poles (eight) of magnet poles are provided for the nine poles (nine) teeth 84b,. By providing the rotor 83 including the portions 90,..., 90, generation of cogging torque can be suppressed.
In addition, the pair of stators 84 and 84 sandwiching the rotor 83 from both sides in the direction of the rotation axis O is energized and controlled so that the field magnetic flux generated by the permanent magnet piece of the rotor 83 is swept between the pair of stators 84 and 84. The output from the motor 80 while canceling the generation of unnecessary excitation force by offsetting the excitation force in the axial direction caused by the one stator 84 and the excitation force in the axial direction caused by the other stator 84. The possible torque can be increased.

  Furthermore, according to the electric power steering apparatus 10 including the motor 80, the torque that can be output with relatively low vibration in which the generation of cogging torque and the exciting force in the axial direction is suppressed is increased. The relatively high torque axial gap type motor 80 can output an appropriate auxiliary torque with respect to the steering torque, and the driver can control the steering system while preventing the motor 80 from becoming complicated. It is possible to prevent the operation 22 from feeling uncomfortable.

  In the embodiment described above, the permanent magnet pieces 83a, ..., 83a of the plurality of magnet pole portions 90, ..., 90 accommodated in the rotor frame 85 are set so that the magnetization directions thereof are the same. May be.

  In the above-described embodiment, the rotor 83 is made of eight (that is, eight poles) magnet pole portions 90,..., 90 and a nonmagnetic material that accommodates these magnet pole portions 90,. However, the present invention is not limited to this. For example, as in the first modification shown in FIG. 7 and Table 1 below, the rotor 83 has four magnet pole portions (that is, four poles). , 90, four (that is, four poles) magnetic material pole portions 83b,..., 83b, and a rotor frame 85 made of a non-magnetic material. May be accommodated in the rotor frame 85 in a state of being alternately arranged in the circumferential direction.

In this first modification, the magnet pole portion 90 and the magnetic material pole portion 83b housed in the rotor frame 85 are sandwiched between the inner peripheral cylindrical portion 85b and the outer peripheral cylindrical portion 85c from both sides in the radial direction. And it arrange | positions so that it may adjoin in the circumferential direction via the radial direction rib 85a.
The magnetic material pole portion 83b includes a plurality of pole portion through holes 86,..., 86 penetrating in a direction parallel to the rotation axis O direction, and each pole portion through hole 86 has, for example, a cross-sectional shape with respect to the rotation axis O direction. Is a long hole having a radial direction as a longitudinal direction, and the plurality of pole portion through holes 86,..., 86 are arranged at predetermined intervals in the circumferential direction.

  In this first modification, the permanent magnet pieces 83a, ..., 83a of the plurality of magnet pole portions 90, ..., 90 accommodated in the rotor frame 85 are set so that the magnetization directions thereof are the same. May be.

  According to the motor 80 according to the first modified example, in the rotor 83, instead of the eight pole (eight) magnet pole portions 90, ..., 90, each of the four pole (four) magnet pole portions 90, ... , 90 and magnetic material pole portions 83b,..., 83b can reduce the amount of permanent magnets required while maintaining the number of pole pairs unchanged. In addition, the magnetic material pole portion 83b alternately arranged with the magnet pole portion 90 in the circumferential direction is provided with the pole portion through hole 86, so that the magnetic path that penetrates the magnetic material pole portion 83b between the pair of stators 84 and 84. Can be formed. As a result, a desired magnetic direction can be imparted to the current magnetic flux generated by the stator windings of each stator 84, the torque that can be output from the motor 80 can be increased, and the pair of stators 84, 84 can be The current magnetic flux waveform can be shaped by the stator windings of the pair of stators 84 and 84 so as to suppress a sudden change in the magnetic resistance at the coil, and the harmonics of the torque ripple and the current magnetic flux waveform can be generated. Can be suppressed and iron loss can be reduced.

  In the above-described embodiment, each stator 84 of the motor 80 includes nine (9 poles) teeth 84b,..., 84b, and the rotor 83 includes eight (8 poles) magnet pole portions 90,. However, the present invention is not limited to this. For example, as in the second modification shown in FIGS. 8 and 9 and Table 1 above, each stator 84 has 12 teeth (12 poles) 84b,. The rotor 83 may include ten (10 poles) magnet pole portions 90,.

In the second modification, each stator 84 corresponds to six types of 6N main poles (for example, N = 2) including, for example, U ⁺ , V ⁺ , W ⁺ , U ⁻ , V ⁻ , and W ⁻ poles. Teeth 84b,..., 84b are provided. The U ⁻ , V ⁻ , and W ⁻ poles of the other stator 84 face each other in the direction of the rotation axis O with respect to the U ⁺ , V ⁺ , and W ⁺ poles of the one stator 84. The energized state of the teeth 84b and the teeth 84b of the other stator 84 is set so as to be reversed by an electrical angle.

  In the second modification of the above-described embodiment, the permanent magnet pieces of the plurality of magnet pole portions 90,..., 90 accommodated in the rotor frame 85 are set so that the magnetization directions are the same as each other. May be.

  In the second modification of the above-described embodiment, the rotor 83 is made of ten magnet pole portions 90,..., 90 and a nonmagnetic material that accommodates these magnet pole portions 90,. However, the present invention is not limited to this. For example, as in the third modification shown in FIG. 10 and Table 1 above, the rotor 83 has five magnet pole portions 90 (that is, five poles). , 90, five (ie, five poles) magnetic material pole portions 83b,..., 83b, and a rotor frame 85 made of a nonmagnetic material, the magnet pole portion 90 and the magnetic material pole portion 83b The rotor frame 85 may be housed in an alternating arrangement in the circumferential direction.

In the third modification, the magnet pole portion 90 and the magnetic material pole portion 83b housed in the rotor frame 85 are sandwiched between the inner peripheral cylindrical portion 85b and the outer peripheral cylindrical portion 85c from both sides in the radial direction. And it arrange | positions so that it may adjoin in the circumferential direction via the radial direction rib 85a.
The magnetic material pole portion 83b includes a plurality of pole portion through holes 86,..., 86 penetrating in a direction parallel to the rotation axis O direction, and each pole portion through hole 86 has, for example, a cross-sectional shape with respect to the rotation axis O direction. Is a long hole having a radial direction as a longitudinal direction, and the plurality of pole portion through holes 86,..., 86 are arranged at predetermined intervals in the circumferential direction.

  In this third modification, the permanent magnet pieces 83a, ..., 83a of the plurality of magnet pole portions 90, ..., 90 accommodated in the rotor frame 85 are set so that the magnetization directions thereof are the same. Also good.

  In the embodiment described above, each stator 84 of the motor 80 includes nine (that is, nine poles) teeth 84b,..., 84b, and the rotor 83 includes eight (that is, eight poles) magnet pole portions 90. ,..., 90 are provided, but the present invention is not limited to this. For example, each stator 84 has 12 teeth (that is, 12 poles) as shown in FIGS. 84b,..., 84b, and the rotor 83 may include 14 (that is, 14 poles) magnet pole portions 90,.

In the fourth modified example, each stator 84 corresponds to six types of 6N main poles (for example, N = 2) including, for example, U ⁺ , V ⁺ , W ⁺ , U ⁻ , V ⁻ , and W ⁻ poles. Teeth 84b,..., 84b are provided. The U ⁻ , V ⁻ , and W ⁻ poles of the other stator 84 face each other in the direction of the rotation axis O with respect to the U ⁺ , V ⁺ , and W ⁺ poles of the one stator 84. The energized state of the teeth 84b and the teeth 84b of the other stator 84 is set so as to be reversed by an electrical angle.

  In the fourth modification of the above-described embodiment, the permanent magnet pieces of the plurality of magnet pole portions 90,..., 90 accommodated in the rotor frame 85 are set so that the magnetization directions are the same as each other. May be.

  In the fourth modification of the above-described embodiment, the rotor 83 accommodates 14 (that is, 14 poles) magnet pole portions 90,..., 90 and these magnet pole portions 90,. However, the present invention is not limited to this. For example, as in the fifth modification shown in FIG. 13 and Table 1 above, there are seven rotors 83 (that is, seven poles). ) Magnet pole portions 90,..., 90, seven magnetic material pole portions 83b,..., 83b, and a rotor frame 85 made of a non-magnetic material. The material electrode portions 83b may be accommodated in the rotor frame 85 in a state of being alternately arranged in the circumferential direction.

In this fifth modification, the magnet pole portion 90 and the magnetic material pole portion 83b housed in the rotor frame 85 are sandwiched between the inner peripheral cylindrical portion 85b and the outer peripheral cylindrical portion 85c from both sides in the radial direction. And it arrange | positions so that it may adjoin in the circumferential direction via the radial direction rib 85a.
The magnetic material pole portion 83b includes a plurality of pole portion through holes 86,..., 86 penetrating in a direction parallel to the rotation axis O direction, and each pole portion through hole 86 has, for example, a cross-sectional shape with respect to the rotation axis O direction. Is a long hole having a radial direction as a longitudinal direction, and the plurality of pole portion through holes 86,..., 86 are arranged at predetermined intervals in the circumferential direction.

  In the fifth modification, the permanent magnet pieces 83a, ..., 83a of the plurality of magnet pole portions 90, ..., 90 accommodated in the rotor frame 85 are set so that the magnetization directions thereof are the same. Also good.

  In the embodiment and the first to fifth modifications described above, the magnetization direction is a direction orthogonal to the rotation axis O direction and the radial direction, and both ends in the circumferential direction of the permanent magnet piece 83a of the magnet pole portion 90. A sub-magnet portion 91 including sub-permanent magnet pieces 91a and 91a arranged at positions shifted to one side in the rotation axis O direction and positions shifted to the other side from the arrangement position of the main permanent magnet piece 83a in the vicinity of the portion. May be.

For example, the motor 80 according to the sixth modification shown in FIG. 14 is configured by including a plurality of sub-magnet portions 91,..., 91 in the motor 80 according to the above-described embodiment (that is, the motor 80 shown in FIG. 5). ing.
The sub magnet portion 91 is disposed between the magnet pole portions 90 and 90 adjacent in the circumferential direction on one side and the other side in the rotation axis O direction, and is a sub permanent magnet piece disposed on one side in the rotation axis O direction. 91a and the sub permanent magnet piece 91a disposed on the other side sandwich the radial rib 85a of the rotor frame 86 from both sides in the direction of the rotation axis O.
In the sixth modification, the magnet pole portion 90 includes a pair of magnetic material members 92 and 92 that cover one surface in the thickness direction of the permanent magnet piece 83a (that is, the rotation axis O direction) and the other surface. The magnetic material member 92 has a substantially sector shape in which the cross-sectional shape in the thickness direction is the same as that of the permanent magnet piece 83a.
Then, on one side and the other side in the direction of the rotation axis O, the sub permanent magnet pieces 91a and 91a adjacent in the circumferential direction sandwich the magnetic material member 92 from both sides in the circumferential direction.

A pair of sub permanent magnet pieces 91a, 91a facing each other in the circumferential direction via the magnetic material member 92, and a pair of sub permanent magnets facing each other in the direction of the rotation axis O via the radial rib 85a of the rotor frame 86. The pieces 91a and 91a are set so that the magnetization directions are different from each other.
The pair of sub permanent magnet pieces 91a and 91a disposed on one side of the permanent magnet piece 83a of the magnet pole portion 90 in the direction of the rotation axis O is one of the permanent magnet pieces 83a magnetized in the direction of the rotation axis O. A pair of sub permanent magnet pieces 91a and 91 arranged on the other side in the direction of the rotation axis O are opposed to the other of the permanent magnet pieces 83a magnetized in the direction of the rotation axis O. The same magnetic pole is made to face the magnetic pole on the side.

  That is, for example, with respect to the permanent magnet piece 83a in which one side in the rotation axis O direction is an N pole and the other side is an S pole, a pair of magnetic material members 92 are sandwiched from both sides in the circumferential direction on one side in the rotation axis O direction. The sub permanent magnet pieces 91a, 91a are arranged so that their N poles face each other in the circumferential direction, and a pair of sub permanent magnet pieces that sandwich the magnetic material member 92 from both sides in the circumferential direction on the other side in the rotation axis O direction. 91a and 91a are arrange | positioned so that a mutual S pole may oppose in the circumferential direction.

  And each magnet pole part 90 and each submagnet part 91 accommodated in the rotor frame 86 are pinched | interposed from the both sides of radial direction by the inner peripheral side cylindrical part 85b and the outer peripheral side cylindrical part 85c.

  According to the motor 80 according to the sixth modification, a pair of sub permanent magnets magnetized in the direction perpendicular to the magnetization direction of the permanent magnet piece 83a in the vicinity of both ends in the circumferential direction of the permanent magnet piece 83a of the magnet pole portion 90. By providing the magnet pieces 91a and 91a, the magnetic flux of the permanent magnet piece 83a and the sub permanent magnet pieces 91a and 91a can be converged by the magnetic flux lens effect by the so-called permanent magnet Halbach arrangement, and the stators 84 and 84 are fixed. The amount of magnetic flux interlinked with the child winding can be increased.

Further, for example, the motor 80 according to the seventh modification shown in FIG. 15 includes a plurality of sub-magnet portions 91,... In the motor 80 according to the first modification described above (that is, the motor 80 including the rotor 83 shown in FIG. 7). , 91.
That is, in the seventh modification, in the rotor 83 according to the sixth modification described above (that is, the rotor 83 shown in FIG. 14), instead of the eight poles (eight pieces) of the magnet pole portions 90,. By providing each of the four poles (four pieces) of magnet pole portions 90, ..., 90 and magnetic material pole portions 83b, ..., 83b, the amount of permanent magnets required is reduced while maintaining the number of pole pairs unchanged. be able to.

  In the sixth modification and the seventh modification described above, the magnetic material members 92 and 92 that sandwich the permanent magnet piece 83a of the magnet pole portion 90 from both sides in the direction of the rotation axis O may be omitted.

It is a lineblock diagram of the electric power steering device concerning one embodiment of the present invention. It is a lineblock diagram of the electric power steering device concerning one embodiment of the present invention. It is an AA arrow directional view shown in FIG. It is a BB arrow directional view shown in FIG. It is a perspective view of the motor of one embodiment of the present invention. It is a disassembled perspective view of the rotor of the motor of one Embodiment of this invention. It is a disassembled perspective view of the rotor of the motor which concerns on the 1st modification of one Embodiment of this invention. It is a perspective view of the motor which concerns on the 2nd modification of one Embodiment of this invention. It is a disassembled perspective view of the rotor of the motor which concerns on the 2nd modification of one Embodiment of this invention. It is a disassembled perspective view of the rotor of the motor which concerns on the 3rd modification of one Embodiment of this invention. It is a perspective view of the motor which concerns on the 4th modification of one Embodiment of this invention. It is a disassembled perspective view of the rotor of the motor which concerns on the 4th modification of one Embodiment of this invention. It is a disassembled perspective view of the rotor of the motor which concerns on the 5th modification of one Embodiment of this invention. It is a disassembled perspective view of the motor which concerns on the 6th modification of one Embodiment of this invention. It is a disassembled perspective view of the motor which concerns on the 7th modification of one Embodiment of this invention.

Explanation of symbols

10. Electric power steering device 70 Steering torque sensor (steering torque detecting means)
78 Control means 80 Motor 83 Rotor 83a Permanent magnet piece (main permanent magnet piece)
83b Magnetic material pole part 84 Stator (1st stator, 2nd stator)
84b Teeth 86 Pole through hole (Pole through part)
90 Magnet pole part (main magnet part)
91 Sub magnet portion 91a Sub permanent magnet piece (first sub permanent magnet piece, second sub permanent magnet piece)

Claims (5)

An axial gap type motor comprising a rotor rotatable around a rotation axis, and a stator disposed opposite to the rotor in the rotation axis direction;
The rotor includes a main magnet part and a magnetic material pole part of four poles arranged alternately in the circumferential direction,
The magnetic material pole part has the same shape as the main magnet part and includes a pole part penetrating part penetrating in the rotation axis direction,
The main magnet portion includes a main permanent magnet piece whose magnetization direction is the rotation axis direction,
The stator includes a pair of first and second stators that are opposed to each other in the rotation axis direction and sandwich the rotor from both sides in the rotation axis direction,
Each said 1st stator and said 2nd stator are equipped with 9 pole teeth, The axial gap type motor characterized by the above-mentioned. An axial gap type motor comprising a rotor rotatable around a rotation axis, and a stator disposed opposite to the rotor in the rotation axis direction;
The rotor includes 5-pole main magnet portions and magnetic material pole portions alternately arranged in the circumferential direction,
The magnetic material pole part has the same shape as the main magnet part and includes a pole part penetrating part penetrating in the rotation axis direction,
The main magnet portion includes a main permanent magnet piece whose magnetization direction is the rotation axis direction,
The stator includes a pair of first and second stators that are opposed to each other in the rotation axis direction and sandwich the rotor from both sides in the rotation axis direction,
Each said 1st stator and said 2nd stator are equipped with 12 pole teeth, The axial gap type motor characterized by the above-mentioned. An axial gap type motor comprising a rotor rotatable around a rotation axis, and a stator disposed opposite to the rotor in the rotation axis direction;
The rotor includes a 7-pole main magnet portion and a magnetic material pole portion alternately arranged in the circumferential direction,
The magnetic material pole part has the same shape as the main magnet part and includes a pole part penetrating part penetrating in the rotation axis direction,
The main magnet portion includes a main permanent magnet piece whose magnetization direction is the rotation axis direction,
The stator includes a pair of first and second stators that are opposed to each other in the rotation axis direction and sandwich the rotor from both sides in the rotation axis direction,
Each said 1st stator and said 2nd stator are equipped with 12 pole teeth, The axial gap type motor characterized by the above-mentioned. The magnetization direction is a direction orthogonal to the rotation axis direction and the radial direction, and deviates from the arrangement position of the main permanent magnet piece to one side in the rotation axis direction in the vicinity of both ends of the main permanent magnet piece in the circumferential direction. The submagnet part which comprises the 2nd subpermanent magnet piece arrange | positioned in the position shifted in the 1st subpermanent magnet piece arrange | positioned in the position and the other side was provided. The axial gap type motor described in any one of the above. An axial gap type motor according to any one of claims 1 to 4,
Steering torque detection means for detecting steering torque;
Control means for driving and controlling the axial gap type motor in accordance with the steering torque detected by the steering torque detecting means and generating auxiliary torque for assisting the steering torque from the axial gap type motor. An electric power steering device.

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