JP2014233189A - Motor, electrically-driven power steering device, and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve simplification of a structure and improvement in performance in a motor, an electrically-driven power steering device, and a vehicle.SOLUTION: A motor includes: a motor rotor assembly 55 in which magnets 43 are provided in the outer peripheral part of a rotor yoke 42 at an equal interval in the circumferential direction; and a motor stator assembly 56 in which a stator core 81 is arranged in the periphery of an excitation coil 82 configured by providing a winding in a ring shape, magnetic paths are formed in the radial direction by arranging a plurality of first magnetic pole parts 83c and a plurality of second magnetic pole parts 84c alternately in the inner peripheral part in the circumferential direction, and which is annually arranged in the outside in the radial direction of a motor rotor assembly 55 with a predetermined gap.

Description

  The present invention relates to an electric motor, an electric power steering device, and a vehicle.

  Examples of the electric motor include those described in the following patent documents. A small stepping motor described in Patent Document 1 rotatably supports a permanent magnet rotor magnetized radially in a plurality of poles in a housing, and a plurality of stators and excitation coils around the rotor in the housing. Are arranged so as to be laminated. The multi-phase annular coil type HB type rotating electrical machine described in Patent Document 2 is a unit rotation in which a permanent magnet is sandwiched from the axial direction by a rotor magnetic pole made of a magnetic body having a plurality of teeth on the outer periphery at an equal pitch. A rotor is formed and a plurality of unit rotors are arranged in the axial direction, and each unit rotor is opposed to each other through an air gap, and a plurality of teeth are provided on a plurality of poles of the stator core. A unit stator is formed by sandwiching an annular coil from the axial direction with a stator iron core so that they are alternately meshed, and a stator having a plurality of unit stators arranged in the axial direction is provided.

JP-A-61-177154 JP 2002-359959 A

  Each of the above-mentioned patent documents describes a configuration in which the stator is a claw pole, but the configuration of the excitation coil, the stator, the teeth (magnetic pole part), etc. is complicated, and the magnetic flux from the rotor is effectively linked to the coil. There is a problem that a sufficient amount of magnetic flux can not be obtained, it is difficult to ensure a sufficient output, and the assembling property is not good.

  The present invention solves the above-described problems, and an object of the present invention is to provide an electric motor, an electric power steering device, and a vehicle that simplify the structure and improve performance.

  In order to achieve the above object, an electric motor according to the present invention includes a motor rotor in which a magnet is provided along the outer peripheral portion of a rotor yoke, and a stator core disposed around an excitation coil configured by providing windings in a ring shape. A plurality of first magnetic poles and second magnetic poles are alternately arranged in the circumferential direction in the circumferential portion, thereby forming a magnetic path along the radial direction and forming an annular shape with a predetermined gap on the outer side in the radial direction of the motor rotor. And a motor stator arranged so that the winding coefficient of the first magnetic pole and the second magnetic pole is substantially equivalent to 1.0.

  Therefore, by arranging a stator core around the excitation coil and forming a motor stator in which a magnetic path along the radial direction is formed by alternating the first magnetic pole and the second magnetic pole along the inner peripheral portion, the configuration of the magnetic pole is A claw pole configuration with a winding coefficient of approximately 1.0 can be achieved, and a sufficient output can be ensured without applying excessive stress to the exciting coil. As a result, the structure can be simplified and the performance can be improved, and an effective magnetic flux amount in which the magnetic flux from the rotor is linked to the coil can be sufficiently secured.

  In the electric motor of the present invention, the plurality of magnetic poles are connected by a connecting portion having a width narrower than the width of the magnetic poles.

  Therefore, by connecting the plurality of magnetic poles by the connecting portion, the rigidity of the magnetic pole can be improved, and the magnetic pole can be manufactured by, for example, press working, and the processing accuracy of the stator core can be improved. In addition, the manufacturing cost can be reduced and the motor efficiency can be improved.

  In the electric motor of the present invention, the magnetic pole is formed by laminating a plurality of plate materials made of a magnetic material.

  Therefore, the magnetic pole can be easily manufactured, and the manufacturing cost can be reduced.

  In the electric motor of the present invention, a magnetic pole member having a ring shape in which the first magnetic pole and the second magnetic pole are connected by the connecting portion is provided, and the first magnetic pole is joined to one side of the stator core in the axial direction. The second magnetic pole is joined to the other side of the stator core in the axial direction.

  Therefore, by using the magnetic pole member having a ring shape in which the first magnetic pole and the second magnetic pole are connected by the connecting portion, the rigidity of the magnetic pole can be improved and the assembly process of the stator core can be simplified. it can.

  In the electric motor of the present invention, the stator core includes an upper stator core having a ring shape and a lower stator core having a ring shape, and the upper stator core extends to an inner peripheral portion in the motor axis direction. The lower stator core is characterized in that the second magnetic pole extending in the motor axial direction is provided on the inner peripheral portion.

  Therefore, by dividing the stator core into the upper stator core and the lower stator core, the assembly of the stator core and the exciting coil can be facilitated and the assembly cost can be reduced.

  In the electric motor of the present invention, the magnetic pole is characterized in that a base end portion joined to the stator core is wide and a tip end portion extending in the axial direction is set narrow.

  Therefore, a magnetic path can be ensured appropriately.

  In the electric motor of the present invention, the stator core is formed by press-forming a magnetic powder material.

  Therefore, the stator core can be manufactured easily and with high accuracy.

  In the electric motor of the present invention, the exciting coil has a plurality of coils arranged in parallel in the axial direction or the radial direction.

  Therefore, when the exciting coil has a plurality of coils, even if one coil is short-circuited, a magnetic path can be formed by another coil.

  In the electric motor of the present invention, a motor driver is individually connected corresponding to the plurality of coils.

  Therefore, by connecting the motor driver individually corresponding to each coil, even if one inverter circuit is partially damaged or one coil is short-circuited, a magnetic path is formed by the other coil. Thus, safety can be improved.

  In the electric motor of the present invention, the motor rotor is characterized in that the magnet is embedded in the rotor yoke.

  Therefore, the reluctance torque can be obtained effectively, and the lost torque can be reduced by reducing the magnet amount.

  In the electric motor of the present invention, the motor rotor includes three rotors arranged in the axial direction, and the three rotors are coupled by a shaft passing through the axial center, while the motor stator is arranged in the axial direction. Three stators are arranged, and the three stators are connected by a frame having at least an outer peripheral portion having a cylindrical shape.

  Therefore, the motor stator can be easily assembled by integrally connecting the outer peripheral portions of the three stators with the frame, and the manufacturing cost can be reduced.

  The electric power steering apparatus of the present invention is characterized in that an auxiliary steering torque is obtained by the electric motor.

  Therefore, even if the auxiliary steering torque is transmitted to the steering person, the operation can be performed in a state in which the uncomfortable feeling is suppressed.

  The vehicle of the present invention is characterized in that the electric power steering device is mounted.

  Therefore, even if the auxiliary steering torque is transmitted to the steering person, the operation can be performed in a state in which the uncomfortable feeling is suppressed.

  According to the electric motor, the electric power steering apparatus, and the vehicle of the present invention, the stator core is disposed around the exciting coil, and the magnetic path along the radial direction is formed by alternately alternating the first magnetic pole and the second magnetic pole along the inner peripheral portion. In addition, since the motor stator is arranged so that the winding coefficient of the first magnetic pole and the second magnetic pole is substantially equivalent to 1.0, the structure can be simplified and the performance can be improved. It is possible to secure a sufficient amount of effective magnetic flux that interlinks with the coil.

FIG. 1 is a schematic configuration diagram of an electric power steering apparatus having an electric motor according to a first embodiment of the present invention. FIG. 2 is a partially cutaway front view showing an example of a speed reducer in the electric power steering apparatus. FIG. 3 is a cross-sectional view illustrating an electric motor. FIG. 4 is a partially cutaway perspective view showing a rotor and a stator in an electric motor. FIG. 5 is a partially cutaway perspective view showing the stator. FIG. 6 is a partially cutaway perspective view showing a stator in an electric motor according to a second embodiment of the present invention. FIG. 7 is a partially cutaway perspective view showing the stator core. FIG. 8 is a partially cutaway perspective view showing a magnetic pole on the stator side. FIG. 9 is a schematic diagram showing details of the conventional magnetic pole and the magnetic pole of the second embodiment. FIG. 10 is a partially cutaway perspective view showing a stator in an electric motor according to a third embodiment of the present invention.

  Exemplary embodiments of an electric motor, an electric power steering apparatus, and a vehicle according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, and when there are two or more embodiments, what comprises combining each embodiment is also included.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an electric power steering apparatus having an electric motor according to a first embodiment of the present invention.

  In the first embodiment, as shown in FIG. 1, the electric motor is a brushless motor 40, and the electric power steering apparatus 10 includes the brushless motor 40, and obtains an auxiliary steering torque by the brushless motor 40. ing. The electric power steering device 10 is mounted on a four-wheel vehicle.

  The electric power steering device 10 includes a steering wheel 11, a steering shaft 12, a steering force assist mechanism 13, a universal joint 14, a lower shaft 15, a universal joint 16, A pinion shaft 17, a steering gear 18, and a tie rod 19 are provided. The electric power steering apparatus 10 includes an ECU (Electronic Control Unit) 20, a torque sensor 21, and a vehicle speed sensor 22.

  The steering shaft 12 has an input shaft 12a and an output shaft 12b. The input shaft 12a has one end connected to the steering wheel 11 and the other end connected to the steering force assist mechanism via the torque sensor 21. 13. The output shaft 12 b has one end connected to the steering force assist mechanism 13 and the other end connected to the universal joint 14. In the present embodiment, the input shaft 12a and the output shaft 12b are formed from a magnetic material such as iron.

  The lower shaft 15 has one end connected to the universal joint 14 and the other end connected to the universal joint 16. The pinion shaft 17 has one end connected to the universal joint 16 and the other end connected to the steering gear 18.

  The steering gear 18 includes a pinion 18a and a rack 18b. The pinion 18a is connected to the pinion shaft 17, and the rack 18b meshes with the pinion 18a. The steering gear 18 is configured as a rack and pinion type. The steering gear 18 converts the rotational motion transmitted to the pinion 18a into a linear motion by the rack 18b. The tie rod 19 is connected to the rack 18b.

  The steering force assist mechanism 13 includes a speed reducer 23 and a brushless motor 40. The reduction gear 23 is connected to the output shaft 12b. The brushless motor 40 is connected to the speed reducer 23 and functions as an electric motor that generates auxiliary steering torque. In the electric power steering apparatus 10, a steering column is configured by the steering shaft 12, the torque sensor 21, and the speed reducer 23. The brushless motor 40 can give auxiliary steering torque to the output shaft 12b of the steering column. That is, the electric power steering apparatus 10 of the first embodiment is a column assist system.

  In this column assist type electric power steering apparatus 10, the distance between the operator and the brushless motor 40 is relatively short, and the torque change or frictional force of the brushless motor 40 may affect the steering person. For this reason, the electric power steering apparatus 10 is required to reduce the frictional force of the brushless motor 40.

  FIG. 2 is a partially cutaway front view showing an example of a speed reducer in the electric power steering apparatus.

  The reduction gear 23 is a worm type reduction gear. The reduction gear 23 includes a reduction gear housing 24, a worm 25, a ball bearing 26 a, a ball bearing 26 b, a worm wheel 27, and a holder 28.

  The worm 25 is coupled to the shaft 41 of the brushless motor 40 by a spline or an elastic coupling (not shown). The worm 25 is rotatably supported by the speed reducer housing 24 by a ball bearing 26 a and a ball bearing 26 b held by the holder 28. The worm wheel 27 is rotatably supported by the speed reducer housing 24. The worm 25 is partially formed with worm teeth 25 a, and the worm teeth 25 a mesh with worm wheel teeth 27 a formed on the worm wheel 27.

  Therefore, the rotational force of the brushless motor 40 is transmitted from the shaft 41 to the worm wheel 27 via the worm 25, and the worm wheel 27 can be rotated. The reduction gear 23 can increase the torque of the brushless motor 40 by the worm 25 and the worm wheel 27. The speed reducer 23 can apply auxiliary steering torque to the output shaft 12b (see FIG. 1) of the steering column.

  As shown in FIG. 1, the torque sensor 21 detects the driver's steering force transmitted to the input shaft 12a via the steering wheel 11 as a steering torque. The vehicle speed sensor 22 detects the traveling speed of the vehicle on which the electric power steering device 10 is mounted. The ECU 20 is configured by electrically connecting a brushless motor 40, a torque sensor 21, and a vehicle speed sensor 22.

  The ECU 20 can acquire signals from the torque sensor 21 and the vehicle speed sensor 22 and control the operation of the brushless motor 40. That is, the ECU 20 acquires the steering torque T from the torque sensor 21, and acquires the traveling speed V of the vehicle from the vehicle speed sensor 22. Then, the ECU 20 is supplied with electric power from a power supply device (for example, an in-vehicle battery) 30 with the ignition switch 29 turned on. The ECU 20 calculates an assist steering command value of the assist command based on the steering torque T and the traveling speed V. Then, the ECU 20 adjusts the power value X supplied to the brushless motor 40 based on the calculated auxiliary steering command value. Further, the ECU 20 acquires the information on the induced voltage from the brushless motor 40 or the information on the rotation of the rotor from the resolver described later as the operation information Y.

  The steering force of the driver (driver) input to the steering wheel 11 is transmitted to the speed reduction device 23 of the steering force assist mechanism 13 via the input shaft 12a. At this time, the ECU 20 acquires the steering torque T input to the input shaft 12 a from the torque sensor 21 and acquires the travel speed V from the vehicle speed sensor 22. Then, the ECU 20 controls the operation of the brushless motor 40. The auxiliary steering torque output by the brushless motor 40 is transmitted to the reduction gear 23.

  The steering torque T (including auxiliary steering torque) output via the output shaft 12 b is transmitted to the lower shaft 15 via the universal joint 14 and is transmitted to the pinion shaft 17 via the universal joint 16. The steering force transmitted to the pinion shaft 17 is transmitted to the tie rod 19 via the steering gear 18, and the steered wheels can be steered.

  3 is a cross-sectional view showing an electric motor, FIG. 4 is a partially cutaway perspective view showing a rotor and a stator in the electric motor, and FIG. 5 is a partially cutaway perspective view showing a stator.

  As shown in FIG. 3, the brushless motor 40 includes a housing 51, a bearing 52, a bearing 53, a resolver 54, a motor rotor assembly 55, and a motor stator assembly 56 as a brushless motor stator. Yes.

  The housing 51 includes a cylindrical housing 51a having a bottomed cylindrical shape and a front bracket 51b having a disk shape. The cylindrical housing 51a has one end opened and a bottom 51c formed integrally with the other end. The front bracket 51b is attached to the cylindrical housing 51a so as to close the end portion on the opening side of the cylindrical housing 51a. In addition, as a magnetic material which forms this cylindrical housing 51a, general steel materials, such as a cold rolled steel plate (SPCC: Steel Plate Cold Commercial), electromagnetic soft iron, etc. are applicable, for example. Further, the front bracket 51b serves as a flange for attaching the brushless motor 40 to a desired device.

  The bearing 52 is provided inside the housing 51 and at a substantially central portion of the front bracket 51b. The bearing 53 is provided inside the housing 51 and at a substantially central portion of the bottom 51c of the cylindrical housing 51a. The bearing 52 rotatably supports one end of the shaft 41 that is a part of the motor rotor assembly 55 disposed inside the housing 51. Moreover, the bearing 53 is supporting the other end of the shaft 41 rotatably. Therefore, the shaft 41 is supported by the two bearings 52 and 53 and can rotate as the axis of the rotation center Zr.

  The resolver 54 is supported by a terminal block 57 provided on the front bracket 51b side of the shaft 41. The resolver 54 detects the rotational position (rotational phase) of the motor rotor assembly 55 (shaft 41). The resolver 54 has a resolver rotor 54a and a resolver stator 54b. The resolver rotor 54a is attached to the outer peripheral surface of the shaft 41 by press fitting or the like. On the other hand, the resolver stator 54b is attached to the terminal block 57 (front bracket 51b) so as to face the resolver rotor 54a via a gap having a predetermined interval.

  As shown in FIGS. 3 to 5, the motor rotor assembly 55 includes a first rotor 61, a second rotor 62, and a third rotor 63. The first rotor 61, the second rotor 62, and the third rotor 63 are stacked with a predetermined gap along the axial center (rotation center Zr) direction of the shaft 41, and shifted by a predetermined angle along the circumferential direction. Are arranged. The first rotor 61, the second rotor 62, and the third rotor 63 have hollow holes 61 a, 62 a, 63 a formed at the center positions, and are press-fitted into the outer peripheral surface of the shaft 41. , 62, 63 are integrated to form a motor rotor assembly 55. In addition, you may shape | mold the shaft 41 and each rotor 61, 62, 63 integrally.

  The motor rotor assembly 55 is disposed inside the housing 51 so as to be rotatable about the rotation center Zr with respect to the housing 51. In addition to the shaft 41, the first rotor 61 has a rotor yoke 42 and a magnet 43. The shaft 41 is formed in a cylindrical shape. The rotor yoke 42 is formed in a cylindrical shape. Similarly to the first rotor 61, the second rotor 62 and the third rotor have a shaft 41, a rotor yoke 42, and a magnet 43.

  Each rotor yoke 42 is manufactured by laminating thin plates such as electromagnetic steel plates and cold-rolled steel plates by a method such as bonding, bossing, and caulking. The rotor yoke 42 is sequentially stacked in the mold and discharged from the mold. The rotor yoke 42 has a shaft 41 press-fitted into the hollow portions (hollow holes 61a, 62a, 63a), and both are fixed integrally.

  In each rotor 61, 62, 63, a plurality of magnets 43 are embedded along the outer circumferential direction of the rotor yoke 42. That is, each of the rotors 61, 62, 63 is an embedded magnet type rotor (IPM) in which a magnet 43 is embedded at a predetermined position. The magnet 43 is a permanent magnet, and S poles and N poles are alternately arranged at equal intervals in the circumferential direction of the rotor yoke 42. Therefore, the motor rotor assembly 55 has eight poles because the N poles and the S poles are alternately arranged on the outer peripheral side in the circumferential direction.

  In this case, the circumferential positions of the magnets 43 in the three-phase rotors 61, 62, and 63 are set so as to be shifted by a predetermined angle (120 degrees in electrical angle).

  The motor stator assembly 56 includes a first stator 71, a second stator 72, and a third stator 73. The first stator 71, the second stator 72, and the third stator 73 are stacked and arranged with a predetermined gap along the axis (rotation center Zr) direction of the shaft 41. The first stator 71, the second stator 72, and the third stator 73 each have an annular shape, and the outer peripheral surface side and both end surface sides are covered with a resin frame 74, so that they are integrally coupled. The frame 74 is fixed to the inner peripheral surface of the cylindrical housing 51a, for example, by fitting. The frame 74 may be a resin molded product, or may be a resin mold in which the stators 71, 72, 73 are molded with resin.

  The motor stator assembly 56 is provided in a cylindrical shape so as to surround the motor rotor assembly 55 from the outside in the cylindrical housing 51a. The center axis of the motor stator assembly 56 coincides with the rotation center Zr of the motor rotor 55.

  The first stator 71 has a stator core 81 and an excitation coil 82. The stator core 81 has an annular shape and accommodates an exciting coil 82 having an annular shape (ring shape). Similarly to the first stator 71, the second stator 72 and the third stator 73 have a stator core 81 and an excitation coil 82.

  As shown in detail in FIG. 5, the stator core 81 has an upper stator core 83 and a lower stator core 84. Stator core 81 (upper stator core 83, lower stator core 84) is formed of, for example, a magnetic material such as an electromagnetic steel plate or a thin plate such as a cold rolled steel plate.

  The upper stator core 83 includes an upper disk portion 83a having a horizontal ring shape, an upper cylindrical portion 83b having a vertical ring shape, and a plurality of magnetic pole portions 83c. That is, in the upper stator core 83, the upper end portion of the upper cylindrical portion 83b is joined to the outer peripheral portion of the upper disc portion 83a, and the magnetic pole portion 83c has a predetermined gap in the circumferential direction on the inner peripheral side of the upper disc portion 83a. Arranged at equal intervals, the upper end portion of each magnetic pole portion 83c is joined to the inner peripheral portion of the upper disc portion 83a. On the other hand, the lower stator core 84 has a lower disk portion 84a having a horizontal ring shape, a lower cylindrical portion 84b having a vertical ring shape, and a plurality of magnetic pole portions 84c. That is, in the lower stator core 84, the lower end portion of the lower cylindrical portion 84b is joined to the outer peripheral portion of the lower disc portion 84a, and the magnetic pole portion 84c has a predetermined gap in the circumferential direction on the inner peripheral side of the lower disc portion 84a. Arranged at equal intervals, the lower end portion of each magnetic pole portion 84c is joined to the inner peripheral portion of the lower disc portion 84a.

  Therefore, the stator core 81 of each of the stators 71, 72, 73 is configured by combining the upper stator core 83 and the lower stator core 84, and the magnetic pole portion 83c and the magnetic pole are formed on the inner peripheral side, that is, on the rotors 61, 62, 63 side. It has a claw pole configuration in which the portions 84c are alternately arranged. In this case, the circumferential positions of the magnetic pole portions 83c and 84c of the stator core 81 in the three-phase stators 71, 72, and 73 are set to the same position.

  In this case, the magnetic pole part 83c and the magnetic pole part 84c have the same shape, and the base end part joined to the stator cores 83 and 84 and the tip part in the axial direction have the same width. However, the shape of the magnetic pole portions 83c and 84c is not limited to this shape. For example, the base end part joined to each stator core 83, 84 in the magnetic pole part may be wide, and the tip part extending in the axial direction may be narrow, trapezoidal, triangular, sinusoidal, etc. The magnetic path can be appropriately secured depending on the shape.

  In this embodiment, the circumferential positions of the magnets 43 in the rotors 61, 62, and 63 of the motor rotor assembly 55 are shifted by a predetermined angle, while the magnetic pole portions of the stator cores 81 in the stators 71, 72, and 73 of the motor stator assembly 56 are used. Although the circumferential positions of 83c and 84c are set to the same position, the present invention is not limited to this configuration. For example, while the circumferential positions of the magnets 43 in the rotors 61, 62, and 63 of the motor rotor assembly 55 are the same position, the magnetic pole portions 83 c and 84 c of the stator core 81 in the stators 71, 72, and 73 of the motor stator assembly 56. The circumferential position may be shifted by a predetermined angle.

  Each stator core 81 is manufactured by laminating thin plates such as electromagnetic steel plates and cold-rolled steel plates by a method such as adhesion, bossing, and caulking. In addition, each stator core 81 may be formed by molding iron powder (magnetic powder material) by applying pressure with a mold. In this case, the stator core 81 can be easily manufactured with high accuracy. can do.

  The exciting coil 82 is in a linear electric wire, and is configured by winding a plurality of the electric wires in a ring shape. The exciting coil 82 is provided with insulators 85 as insulating members on the upper side, the lower side, and the inner side. The insulator 85 is for insulating the exciting coil 82 and the stator core 81 and is formed of a heat resistant member. Therefore, the number of magnetic poles can be reduced, and the coil end can be eliminated to reduce the amount of invalid coil with respect to the torque. As a result, the cost can be reduced, and the brushless motor 40 can be reduced. It can be made compact in the direction of the heart.

  The exciting coil 82 has a configuration in which an insulator 85 is disposed around the periphery except for the outer peripheral side, and is sandwiched from above and below by the upper stator core 83 and the lower stator core 84, so that the upper stator core 83, the exciting coil 82 (insulator 85), and the lower stator core. 84 are assembled in close contact with each other. At this time, the upper stator core 83 and the lower stator core 84 are in contact with the lower end portion of the upper cylindrical portion 83b and the upper end portion of the lower cylindrical portion 84b. Further, in the upper stator core 83 and the lower stator core 84, the exciting coil 82 (insulator 85) is sandwiched from above and below by the upper disc portion 83a and the lower disc portion 84a. Further, the magnetic pole portion 83 c of the upper stator core 83 enters the gap between the magnetic pole portions 84 c in the lower stator core 84, and the magnetic pole portion 84 c of the lower stator core 84 enters the gap between the magnetic pole portions 83 c in the upper stator core 83. In the lower stator core 84, the magnetic pole portions 83c and the magnetic pole portions 84c are alternately arranged with a predetermined gap in the circumferential direction.

  The stators 71, 72, 73 are connected to respective excitation coils 82 by motor drivers via unillustrated U-phase, V-phase, and W-phase wires.

  The motor stator assembly 56 including the first stator 71, the second stator 72, and the third stator 73 is a radial direction of the motor rotor assembly 55 including the first rotor 61, the second rotor 62, and the third rotor 63. Are arranged annularly with a predetermined interval (gap) on the outside. The motor stator assembly 56 has N poles and S poles alternately arranged in the circumferential direction on the inner circumference side by the magnetic pole portions 83c and 84c, and the number of poles is the same as that of the motor rotor assembly 55. It has 8 poles.

  The brushless motor 40 of the first embodiment has a configuration in which a motor rotor assembly 55 is formed by stacking a first rotor 61, a second rotor 62, and a third rotor 63 with a predetermined gap, and a motor stator assembly 56 is formed with a first stator 71. The second stator 72 and the third stator 73 are stacked with a predetermined gap, and the motor rotor assembly 55 and the motor stator assembly 56 are arranged with a gap. That is, each of the exciting coils 82 of the three stators 71, 72, 73 is a U phase, a V phase, and a W phase in a three phase winding (three phase winding), and the motor stator assembly 56 is a U phase. A first stator 71, a second stator 72 that is a V phase, and a third stator 73 that is a W phase are stacked in the axial direction of the motor rotor assembly 55. Therefore, in the motor stator assembly 56, the stators 71, 72, and 73 have upper and lower stator cores 81 by arranging a plurality of magnetic pole portions 83 c and 84 c having S poles and N poles in the inner circumferential portion alternately in the circumferential direction. A magnetic path is formed along the radial direction toward the magnetic pole portions 83c and 84c.

  In the brushless motor 40 of the first embodiment, in the motor stator assembly 56 (stators 71, 72, 73), the configuration of the magnetic pole portions 83c, 84c is approximately 1.0 (full pitch winding). It has become. The winding coefficient k can be expressed by distributed winding coefficient × short-pitch winding coefficient, and 0 ≦ k ≦ 1.0. That is, the magnetic flux generated from the motor rotor assembly 55 (rotors 61, 62, 63) is configured to increase the effective magnetic flux amount interlinked with the exciting coil 82 in the motor stator assembly 56 (stators 71, 72, 73). ing. The interlinkage magnetic flux is the number of lines of magnetic force that penetrate one current.

  As described above, in the electric motor according to the first embodiment, the motor rotor assembly 55 in which the magnets 43 are provided on the outer peripheral portion of the rotor yoke 42 at equal intervals in the circumferential direction, and the excitation coil configured by providing the windings in a ring shape. The stator core 81 is arranged around the 82, and a plurality of first magnetic pole portions 83c and second magnetic pole portions 84c are alternately arranged in the circumferential direction on the inner circumferential portion, thereby forming a magnetic path along the radial direction and a motor rotor. A motor stator assembly 56 is provided on the outer side in the radial direction of the assembly 55 so as to form a ring with a predetermined gap so that the winding coefficient of the magnetic poles 83c and 84c is approximately equivalent to 1.0. ing.

  Accordingly, the stator core 81 is disposed around the exciting coil 82, and the motor stator assembly 56 in which the first magnetic pole portion 83c and the second magnetic pole portion 84c are alternately formed along the inner peripheral portion to form a magnetic path along the radial direction. By doing so, it becomes possible to make the configuration of the magnetic poles a claw pole configuration in which the winding coefficient k is approximately 1.0. Therefore, a sufficient output equivalent to a winding coefficient of 1.0 can be secured without applying excessive stress to the exciting coil 82 like the nozzle winding and the inserter winding, thereby simplifying the structure and improving the performance. Improvements can be made.

  In the electric motor according to the first embodiment, as the stator core 81, an upper stator core 83 having a ring shape and a lower stator core 84 having a ring shape are provided, and a first that extends in the motor axial direction on the inner peripheral portion of the upper stator core 83. A magnetic pole part 83 c is provided, and a second magnetic pole part 84 c extending in the motor axial direction is provided on the inner peripheral part of the lower stator core 84. Therefore, by dividing the stator core 81 into the upper stator core 83 and the lower stator core 84, the assembly of the stator core 81 and the exciting coil 82 can be facilitated and the assembly cost can be reduced.

  In the electric motor of the first embodiment, a magnet 43 is embedded in the rotor yoke 42 of the motor rotor assembly 55. Therefore, the reluctance torque can be obtained effectively, and the amount of use of the magnet 43 can be reduced to reduce the lost torque.

  In the electric motor of the first embodiment, as the motor rotor assembly 55, three rotors 61, 62, 63 are arranged at predetermined intervals in the axial direction, and a shaft that passes through the axial centers of the rotors 61, 62, 63. On the other hand, as a motor stator assembly 56, three stators 71, 72, 73 are arranged at predetermined intervals in the axial direction as a motor stator assembly 56, and the outer peripheral portions of the stators 71, 72, 73 have a cylindrical shape. They are connected by a frame 74. Therefore, by integrally coupling the outer peripheral portions of the three stators 71, 72, 73 with the frame 74, the motor stator assembly 56 can be easily assembled, and the manufacturing cost can be reduced. In this case, the three rotors 61, 62, 63 and the three stators 71, 72, 73 are arranged with a predetermined interval, but may be arranged in contact with each other without a predetermined interval.

  In the electric power steering apparatus according to the first embodiment, the auxiliary steering torque is obtained by the brushless motor 40. Therefore, even if the auxiliary steering torque is transmitted to the steering person, the operation can be performed in a state in which the uncomfortable feeling is suppressed.

(Second Embodiment)
6 is a partially cutaway perspective view showing a stator in an electric motor according to a second embodiment of the present invention, FIG. 7 is a partially cutaway perspective view showing a stator core, and FIG. 8 is a partially cutout showing a stator-side magnetic pole. FIG. 9 is a schematic diagram showing details of a conventional magnetic pole and the magnetic pole of the second embodiment.

  In the second embodiment, as shown in FIGS. 6 to 8, the electric motor is a brushless motor, and a motor rotor assembly (not shown) and a motor stator assembly as a brushless motor stator in a housing (not shown). 101 is accommodated. The housing and the motor rotor have the same configuration as that of the first embodiment described above.

  The motor stator assembly 101 includes a first stator 111, a second stator 112, and a third stator 113. The first stator 111, the second stator 112, and the third stator 113 are stacked and arranged with a predetermined gap along the axial direction of the shaft of the motor rotor assembly. The first stator 111, the second stator 112, and the third stator 113 each have an annular shape, and the outer peripheral surface side and both end surface sides are covered with a frame (not shown), and are integrally coupled.

  The first stator 111 has a stator core 121 and an excitation coil 122. The stator core 121 has an annular shape, and accommodates an exciting coil 122 having an annular shape (ring shape). Similarly to the first stator 111, the second stator 112 and the third stator 113 have a stator core 121 and an excitation coil 122.

  As shown in FIG. 7, the stator core 121 has an upper stator core 123 and a lower stator core 124. The upper stator core 123 has an upper disc portion 123a having a horizontal ring shape and an upper cylindrical portion 123b having a vertical ring shape. That is, in the upper stator core 123, the upper end portion of the upper cylindrical portion 123b is joined to the outer peripheral portion of the upper disc portion 123a. On the other hand, the lower stator core 124 is joined to a lower disk portion 124a having a horizontal ring shape and a lower cylindrical portion 124b having a vertical ring shape.

  Moreover, the stator core 121 has a plurality of magnetic pole plates 125 as shown in FIG. The magnetic pole plate 125 is a ring-shaped plate having a predetermined width. In the magnetic pole plate 125, eight rectangular openings 126 are formed at equal intervals in the circumferential direction by forming eight rectangular openings 126 at equal intervals in the circumferential direction. The magnetic pole portions 127 and 128 are connected by two connecting portions 125 a and 125 b having a width narrower than the width of the magnetic pole plate 125. The plurality of magnetic pole plates 125 are laminated so that the positions in the circumferential direction of the magnetic pole portions 127 and 128 coincide with each other. In this case, the plurality of magnetic pole plates 125 are stacked to a height that is substantially the same as the combined height of the upper stator core 123 and the lower stator core 124.

  The upper stator core 123 and the lower stator core 124 are combined vertically, and a plurality of magnetic pole plates 125 stacked on the inner peripheral side of the upper stator core 123 and the lower stator core 124 are arranged and joined. In this case, the upper stator core 123 is formed with a plurality of projecting portions projecting inward in the radial direction corresponding to the magnetic pole portions 127, and the lower stator core 124 is inward in the radial direction corresponding to the magnetic pole portions 128. A plurality of projecting portions projecting toward the top are formed. Therefore, the plurality of magnetic pole plates 125 are joined to the protruding portions of the upper stator core 123 corresponding to the magnetic pole portions 127 at the upper end portions, and a predetermined gap is secured from the lower stator core 124 at the lower end portions. In addition, each of the magnetic pole plates 125 is joined to the protruding portion of the lower stator core 124 corresponding to each magnetic pole portion 128 at the lower end portion, and a predetermined gap is secured from the upper stator core 123 at the upper end portion.

  The magnetic pole plate 125 is formed of, for example, a magnetic material such as an electromagnetic steel plate or a thin plate such as a cold rolled steel plate. In this case, it is only necessary to punch the thin plate into the shape of the magnetic pole plate 125 by press working using a mold, and it becomes possible to improve workability and work accuracy. Further, the plurality of magnetic pole plates 125 are manufactured by being laminated by a method such as bonding, bossing, and caulking.

  The configurations of the upper stator core 123, the lower stator core 124, and the magnetic pole plate 125 are not limited to the configurations described above. For example, a configuration in which one magnetic pole plate 125 is positioned on the inner peripheral portion of the upper stator core 123 and a configuration in which one magnetic pole plate 125 is positioned on the inner peripheral portion of the lower stator core 124 are provided. A plurality of stacked magnetic pole plates 125 may be sandwiched between the magnetic pole plate 125 of 123 and the magnetic pole plate 125 of the lower stator core 124.

  Therefore, the stator core 121 of each of the stators 111, 112, and 113 is configured by combining the upper stator core 123, the lower stator core 124, and a plurality of magnetic pole plates 125, and the magnetic pole part 127 and the magnetic pole part 128 are provided on the inner peripheral side. The claw pole configuration is arranged alternately.

  The upper stator core 123, the lower stator core 124, and the magnetic pole plate 125 are manufactured from thin plates such as electromagnetic steel plates and cold-rolled steel plates.

  The exciting coil 122 is in a linear electric wire, and is configured by winding a plurality of the electric wires in a ring shape. In this exciting coil 122, insulators 129 as insulating members are arranged on the upper side, the lower side, and the inner side. The insulator 129 is for insulating the exciting coil 122 and the stator core 121 and is formed of a heat resistant member. Accordingly, the number of magnetic poles can be reduced, and the coil end that is ineffective with respect to torque can be reduced by eliminating the coil end. As a result, the cost can be reduced, and the brushless motor can be reduced in the axial direction. Can be made compact.

  The exciting coil 122 is a form in which an insulator 129 is disposed around the periphery except for the outer peripheral side, and is sandwiched from above and below by the upper stator core 123 and the lower stator core 124, so that the upper stator core 123, the exciting coil 122 (insulator 129), and the lower stator core. 124 are assembled in close contact with each other. At this time, the upper stator core 123 and the lower stator core 124 are in contact with the lower end portion of the upper cylindrical portion 123b and the upper end portion of the lower cylindrical portion 124b. Further, the upper stator core 123 and the lower stator core 124 have the exciting coil 122 (insulator 129) sandwiched from above and below by the upper disc portion 123a and the lower disc portion 124a. Furthermore, by arranging a plurality of magnetic pole plates 125 laminated on the inner peripheral side of the upper stator core 123 and the lower stator core 124, the magnetic pole parts 127 and the magnetic pole parts 128 are alternately arranged with a predetermined gap in the circumferential direction. Be placed.

  The motor stator assembly 101 composed of the first stator 111, the second stator 112, and the third stator 113 has a predetermined interval (gap) on the outer side in the radial direction of the motor rotor assembly composed of three rotors (not shown). And is arranged in an annular shape. As shown in FIG. 9, the motor stator assembly 101 has N poles and S poles alternately arranged on the inner peripheral side in the circumferential direction by the magnetic pole portions 127 and 128, so that it is similar to the motor rotor assembly. , 8 magnetic poles are arranged.

  That is, in the conventional motor stator 001, a plurality of slots 003 are formed in the ring-shaped stator core 102, and the windings 104 are disposed across the slots 103. Therefore, in the motor stator assembly 001, the U phase, the V phase, and the W phase are sequentially formed in the circumferential direction, and the N pole and the S pole as magnetic poles determined by the amplitude and frequency of the current are alternately arranged in the circumferential direction. It will be. That is, the magnetic poles (N pole and S pole) generated by passing a current through the stator windings of each phase (U phase, V phase, W phase) are alternately arranged in the circumferential direction. On the other hand, in the motor stator assembly 101 of the second embodiment, the magnetic pole portions 127 and 128 are claw pole type, and the winding coefficient k is approximately 1.0.

  The brushless motor of the second embodiment has a configuration in which a motor rotor assembly is formed by stacking three rotors with a predetermined gap, and the motor stator assembly 101 connects the first stator 111, the second stator 112, and the third stator 113 with a predetermined gap. The motor rotor assembly and the motor stator assembly 101 are arranged with a gap. That is, each of the exciting coils 122 of the three stators 111, 112, and 113 is a U-phase, a V-phase, and a W-phase in a three-phase winding (three-phase winding), and the motor stator assembly 101 is a U-phase. A certain first stator 111, a second stator 112 that is a V phase, and a third stator 113 that is a W phase are stacked in the axial direction of the motor rotor assembly.

  In the brushless motor of the second embodiment, in the motor stator assembly 101 (stator 111, 112, 113), the magnetic pole portions 127, 128 have a winding coefficient k of approximately 1.0. The winding coefficient k can be expressed by distributed winding coefficient × short-pitch winding coefficient, and 0 ≦ k ≦ 1.

  As described above, in the electric motor according to the second embodiment, the plurality of magnetic pole portions 127 and 128 are connected by the connecting portions 125a and 125b having a width narrower than the width of the magnetic pole portions 127 and 128. Accordingly, the rigidity of the magnetic pole portions 127 and 128 can be improved, and the magnetic pole portions 127 and 128 can be manufactured by, for example, press working, the processing accuracy of the stator core 121 can be improved, and the manufacturing cost can be improved. Can be reduced, and the motor efficiency can be improved.

  In the electric motor of the second embodiment, the magnetic pole plate 125 (the magnetic pole portions 127 and 128) is configured by laminating a plurality of plate materials made of a magnetic material. Therefore, the magnetic pole portions 127 and 128 can be easily manufactured, and the manufacturing cost can be reduced. In addition, the magnetic pole plate 125 (the magnetic pole portions 127 and 128) is made of a laminated steel plate, and the shape design that enables automatic lamination within the mold enables dimensional accuracy, gap shortening, and copper loss reduction. Can be achieved.

  In the electric motor of the second embodiment, a magnetic pole plate 125 having a ring shape in which the upper and lower first magnetic pole portions 127 and the second magnetic pole portion 128 are connected by the connecting portions 125a and 125b is provided, and the axial direction of the upper stator core 123 is increased. The first magnetic pole part 127 is joined to one side, and the second magnetic pole part 128 is joined to the other side of the lower stator core 124 in the axial direction. Therefore, by using the magnetic pole plate 125 in which the first magnetic pole 127 and the second magnetic pole part 128 are connected by the connecting parts 125a and 125b, the rigidity of the magnetic pole parts 127 and 128 can be improved and the set of the stator core 121 can be combined. The attaching process can be simplified.

(Third embodiment)
FIG. 10 is a partially cutaway perspective view showing a stator in an electric motor according to a third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the function similar to the Example mentioned above, and detailed description is abbreviate | omitted.

  In the third embodiment, as shown in FIG. 10, the electric motor is a brushless motor, and a motor rotor assembly (not shown) and a motor stator assembly 201 as a brushless motor stator are accommodated in a housing (not shown). Has been configured. The housing and the motor rotor assembly have the same configuration as that of the first embodiment described above.

  The motor stator assembly 201 includes a first stator 71, a second stator 72, and a third stator 73. Each stator 71, 72, 73 has a stator core 81 and an excitation coil 202. The stator core 81 has an annular shape, and accommodates an exciting coil 202 having an annular shape (ring shape).

  The stator core 81 has an upper stator core 83 and a lower stator core 84. The upper stator core 83 has an upper disk portion 83a, an upper cylindrical portion 83b, and a plurality of magnetic pole portions 83c. On the other hand, the lower stator core 84 has a lower disk portion 84a, a lower cylindrical portion 84b, and a plurality of magnetic pole portions 84c.

  Therefore, the stator core 81 of each of the stators 71, 72, 73 is configured by combining the upper stator core 83 and the lower stator core 84, and the magnetic pole portion 83c and the magnetic pole are formed on the inner peripheral side, that is, on the rotors 61, 62, 63 side. It has a claw pole configuration in which the portions 84c are alternately arranged.

  The exciting coil 202 is in a linear electric wire, and is configured by winding a plurality of the electric wires in a ring shape. The exciting coil 202 includes an upper coil 203 and a lower coil 204, and an insulating sheet (insulator) 205 is disposed between the upper coil 203 and the lower coil 204. The exciting coil 202 is provided with insulators 206 as insulating members on the upper side, the lower side, and the inner side. The insulator 206 is for insulating the exciting coil 202 and the stator core 81 and is formed of a heat resistant member. Accordingly, the number of magnetic poles can be reduced, and the coil end that is ineffective with respect to torque can be reduced by eliminating the coil end. As a result, the cost can be reduced, and the brushless motor can be reduced in the axial direction. It can be made compact.

  The stators 71, 72, 73 are connected to respective excitation coils 202 by motor drivers via unillustrated U-phase, V-phase, and W-phase wires. In this case, the exciting coil 202 is provided with the upper coil 203 and the lower coil 204 arranged in parallel, and the upper coil 203 and the lower coil 204 are connected to different motor drivers via electric wires, respectively. Therefore, even if one of the upper coil 203 and the lower coil 204 fails, the other can control the current.

  The excitation coil 202 composed of the upper coil 203 and the lower coil 204 is configured in such a manner that an insulator 206 is disposed around the periphery except for the outer peripheral side, and is sandwiched from above and below by the upper stator core 83 and the lower stator core 84, thereby exciting with the upper stator core 83. The coil 202 (insulator 206) and the lower stator core 84 are assembled in close contact with each other. At this time, the exciting coil 202 has two sets of coils 203 and 204 arranged in the axial direction of the stators 71, 72 and 73.

  The motor stator assembly 201 composed of the first stator 71, the second stator 72, and the third stator 73 has a predetermined interval (gap) on the outer side in the radial direction of the motor rotor assembly composed of three rotors. And arranged in a ring shape. In the motor stator assembly 201, N poles and S poles are alternately arranged on the inner peripheral side in the circumferential direction by the magnetic pole portions 83c and 84c, so that eight magnetic poles are arranged like the motor rotor assembly. Has been.

  The brushless motor of the third embodiment has a configuration in which a motor rotor assembly is formed by stacking three rotors with a predetermined gap, and the motor stator assembly 201 connects the first stator 71, the second stator 72, and the third stator 73 with a predetermined gap. The motor rotor assembly and the motor stator assembly 201 are arranged with a gap. In other words, the excitation coils 202 of the three stators 71, 72, 73 are the U phase, V phase, and W phase in the three-phase winding (three-phase winding), and the motor stator assembly 201 is the U-phase. A first stator 71, a second stator 72 that is a V phase, and a third stator 73 that is a W phase are stacked in the axial direction of the motor rotor assembly.

  In the brushless motor of the third embodiment, in the motor stator assembly 201 (stators 71, 72, 73), the configuration of the magnetic pole portions 83c, 84c has a winding coefficient k of approximately 1.0. The winding coefficient k can be expressed by distributed winding coefficient × short-pitch winding coefficient, and 0 ≦ k ≦ 1.0.

  Thus, in the electric motor of the third embodiment, the exciting coil 202 has a plurality of coils 203 and 204 arranged in parallel in the axial direction. Therefore, even if one coil 203 is short-circuited or opened, another coil 204 can form a magnetic path. In this case, the exciting coil 20 may be constituted by a plurality of coils 203 and 204 arranged in parallel in the radial direction.

  In the electric motor according to the third embodiment, motor drivers are individually connected corresponding to the plurality of coils 203 and 204. Therefore, by individually connecting a motor driver corresponding to each of the coils 203 and 204, even if one coil 203 is short-circuited or opened, a magnetic path is formed by the other coil 204, thereby improving safety. Can be improved.

10 Electric power steering device 40 Brushless motor (electric motor)
41 shaft 42 rotor yoke 43 magnet 51 housing 54 resolver 55 motor rotor assembly 56, 101, 201 motor stator assembly 61 first rotor 62 second rotor 63 third rotor 71, 111 first stator 72, 112 second stator 73, 113 Third stator 81, 121 Stator core 82, 122, 202 Excitation coil 83, 123 Upper stator core 83c Magnetic pole part (first magnetic pole)
84, 124 Lower stator core 84c Magnetic pole part (second magnetic pole)
85,129,206 Insulator (insulating member)
125 Magnetic pole plate (magnetic pole member)
125a, 125b connecting part 127, 128 magnetic pole part (magnetic pole)
203 Upper coil 204 Lower coil 205 Insulation sheet (insulator)

Claims (13)

A motor rotor provided with a magnet along the outer periphery of the rotor yoke;
A stator core is arranged around an exciting coil configured by providing windings in a ring shape, and a plurality of first magnetic poles and second magnetic poles are alternately arranged in the circumferential direction on the inner peripheral portion, thereby magnetizing along the radial direction. A motor stator which is formed so that a path is formed and a winding coefficient of the first magnetic pole and the second magnetic pole is substantially equivalent to 1.0 by forming a ring with a predetermined gap on the outer side in the radial direction of the motor rotor When,
An electric motor comprising:   The electric motor according to claim 1, wherein the plurality of magnetic poles are connected by a connecting portion having a width narrower than a width of the magnetic poles.   The electric motor according to claim 1, wherein the magnetic pole is configured by laminating a plurality of plate materials made of a magnetic material.   A magnetic pole member having a ring shape in which the first magnetic pole and the second magnetic pole are connected by the connecting portion is provided, and the first magnetic pole is joined to one side in the axial direction of the stator core, and the second magnetic pole is provided. 4. The electric motor according to claim 2, wherein the motor is joined to the other side of the stator core in the axial direction. 5.   The stator core includes an upper stator core having a ring shape and a lower stator core having a ring shape, and the upper stator core is provided with the first magnetic pole extending in a motor axial direction on an inner peripheral portion, and 5. The electric motor according to claim 1, wherein the stator core is provided with the second magnetic pole extending in an inner peripheral portion in a motor axis direction. 6.   6. The magnetic pole according to claim 1, wherein a base end portion joined to the stator core is wide and a tip end portion extending in the axial direction is set narrow. The electric motor described in 1.   The electric motor according to any one of claims 1 to 6, wherein the stator core is configured by press-forming a magnetic powder material.   The electric motor according to any one of claims 1 to 7, wherein the excitation coil has a plurality of coils arranged in parallel in an axial direction or in a radial direction.   9. The electric motor according to claim 8, wherein motor drivers are individually connected corresponding to the plurality of coils.   The electric motor according to claim 1, wherein the magnet is embedded in the rotor yoke of the motor rotor.   The motor rotor has three rotors arranged in the axial direction, and the three rotors are connected by a shaft passing through the axial center, while the motor stator has three stators arranged in the axial direction. 11. The electric motor according to claim 1, wherein the three stators are coupled by a frame having at least an outer peripheral portion having a cylindrical shape. 11.   An electric power steering apparatus characterized in that an auxiliary steering torque is obtained by the electric motor according to any one of claims 1 to 11.   13. A vehicle comprising the electric power steering device according to claim 12.

Images