JP2010076752A - Motor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, in-wheel motor device. <P>SOLUTION: A ring-shaped wheel-side gear 2 is fixed to an inner circumferential surface (or an outer circumferential portion of an inner end face) of a wheel 8. A motor 1 is disposed inside the wheel 8 in a substantially radial direction thereof. Motor-side gears 3, 4 are fixed to a rotating shaft projecting from both sides of the motor 1. The motor-side gears 3, 4 mesh with the wheel-side gear 2. The motor 1 rotating at high speed gives a large torque to the wheel 8. Meshing gear surfaces of the wheel-side gear 2 and the motor-side gears 3, 4 are sealed by bulkhead plates 12 fixed to the wheel 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor device, and more particularly to a motor device suitable for an in-wheel motor device.

  For example, an in-wheel motor as described in Patent Document 1 below is effective in reducing the size and weight of an electric power-driven vehicle and improving the fuel consumption. In Patent Document 2, the wheel shaft center portion is attached to the rotating shaft portion of the flange-shaped member, a ring-shaped gear is formed on the end surface of the cylindrical portion of the flange-shaped member, and the ring-shaped gear is fixed to the vehicle body. It is proposed to drive with two motors.

  However, in-wheel motors have various problems that need to be solved. The most important problem is to reduce the size and weight of the motor. The weight of the motor increases the unsprung weight. In order to solve this problem, it is necessary to improve the output per weight of the motor, that is, improve the output density of the motor. However, an increase in the output density of the motor causes an increase in the amount of heat generated by the stator and rotor. That is, when the output of a small motor is increased, the amount of heat to be radiated increases even though the cross-sectional area of the heat radiation path is small. This problem becomes a big problem in the wheel which is not easy to radiate heat.

  Since the permanent magnet synchronous motor does not need to pass a current for magnetic flux formation, it can realize a small and large output motor with little copper loss. However, in a permanent magnet synchronous motor housed in a wheel that is difficult to cool, it is particularly difficult to cool the permanent magnet in the rotor. Eventually, in order to prevent permanent demagnetization, it is required to further improve the cooling capacity of the permanent magnet of the permanent magnet synchronous motor built in the in-wheel motor. In addition, in the in-wheel motor device, reduction of torque ripple and electromagnetic wave noise called cogging torque has been an important problem.

JP 2002-3375544 A JP 2007-134071 A

(Object of invention)
The first object of the present invention is to provide a small, lightweight and large torque motor device built in a wheel. The second object of the present invention is to provide a motor device with a built-in permanent magnet that is excellent in heat dissipation and suitable for an in-wheel motor. The third object of the present invention is to provide a motor device capable of reducing torque ripple and electromagnetic noise reduction.

(Characteristics of the invention)
The motor device of the present invention that achieves the above object is applied to a motor device having a motor built in a wheel of a vehicle that transmits and receives torque with the wheel, and a reduction gear mechanism that meshes with the rotating shaft of the motor and the wheel. Hereinafter, this motor device is referred to as a decelerating in-wheel motor.

  In the first feature of the present invention, the reduction gear mechanism includes a cylindrical member fixed to the wheel inside the wheel or an outer peripheral portion of the end wall portion of the wheel or a ring-shaped wheel side gear fixed to the peripheral wall portion, A motor-side gear fixed to the end of the rotating shaft and meshing with the wheel-side gear;

  This motor is fixed to an axle that extends along the axis of the wheel and rotatably supports the wheel. The rotating shaft extends in a substantially radial direction of the wheel. The wheel has a partition plate that extends radially inward from the peripheral wall portion of the wheel and reaches the axle. The motor and the reduction gear mechanism are accommodated in a wheel sealed by a partition plate.

  That is, the motor device is closed by the partition plate, and a substantially sealed space is formed inside the wheel. This sealed space accommodates the motor and the reduction gear mechanism. The motor has a rotating shaft that extends substantially in the radial direction of the wheel. The reduction gear mechanism is engaged with a wheel-side gear fixed to a ring-shaped wheel-side gear fixed to a peripheral wall portion or an outer peripheral portion of an end wall portion of the wheel, and a rotation shaft of a motor. The axle is preferably a stationary shaft fixed to the vehicle body, but may be supported by the vehicle body through a steering mechanism. The substantially radial direction of the wheel is a range of 30 degrees or less with respect to the radial direction of the wheel. An oil seal member is provided between the inner peripheral edge of the partition plate and the outer peripheral surface of the axle.

  According to this motor device, the in-wheel motor device can be made simple, small and light, and the wheel can be driven strongly by the deceleration torque of the high-speed and high-output motor. Lubricants such as lubricating oil and grease that lubricate the reduction gear mechanism can be prevented from leaking to the outside, and foreign matters from entering the reduction gear mechanism from the outside.

  That is, the motor of this motor apparatus arrange | positions the rotating shaft of a motor in the radial direction of a wheel long compared with the axial direction of a wheel. As a result, the axial length of the stator and rotor of the motor can be increased compared to the case where the rotational axis of the motor is arranged in the axial direction of the wheel. A motor capable of rotation can be employed. As a result, a large torque can be obtained with a simple reduction gear mechanism.

  The torque increased by the deceleration can be directly transmitted to the inner peripheral surface of the peripheral wall of the wheel or the outer peripheral portion of the inner end surface of the end wall. Further, since torque can be output from both sides of the motor, the diameter of the rotating shaft of the motor can be reduced and the rigidity on the wheel side can also be reduced.

  Eventually, this motor device can realize a reduction in size and weight of the torque transmission mechanism in the reduction type in-wheel motor, and therefore can generate a large torque multiplied by the reduction mechanism. This means reducing the unsprung weight of the in-wheel motor. Furthermore, the space allocated to the motor among the spaces in the wheel whose volume is limited can be increased. Furthermore, friction loss of the reduction gear mechanism can be reduced.

  In a preferred embodiment, the motor is composed of a plurality of small motors fixed to the shaft. Each small motor has a rotating shaft extending in a substantially different radial direction of the wheel. The rotating shaft of each small motor meshes with the same wheel side gear through different motor side gears. Preferably, the rotation shafts of the respective small motors are separated by an equal angle in the circumferential direction of the wheel. For example, when two small motors are used, the two small motors are arranged in substantially opposite directions in the radial direction of the wheel. In this way, the balance of the in-wheel motor device is improved. As a result, a reduction type in-wheel motor having a simple and lightweight reduction mechanism can be realized.

  In a preferred embodiment, each small motor receives AC power from a common inverter. However, in the case where a synchronous motor in which the relative position in the circumferential direction between the rotor and the stator of the small motor (referred to as the inter-stator rotor phase phase) corresponds to the AC power phase that supplies power to the stator coil is employed, The stator rotor spatial phases are equalized. In this way, since only one inverter is required, the circuit and wiring can be simplified.

  In a preferred embodiment, each small motor receives AC power separately from a plurality of different inverters. The phases of the alternating currents output by the plurality of inverters are different from each other during straight travel. According to this aspect, since the torque ripple and electromagnetic noise phase of each small motor are different, the torque ripple and electromagnetic noise of the entire in-wheel motor device can be reduced.

  Preferably, each inverter outputs an alternating current of a phase that cancels torque ripple and electromagnetic noise to each small motor. For example, a peak of torque ripple (or a predetermined order harmonic component of electromagnetic noise) generated by one of two small motors and a torque ripple (or a predetermined order harmonic component of electromagnetic noise) generated by the other one These small motors are supplied with phase currents that the valleys overlap when the vehicle is traveling straight ahead.

  For example, when each small motor is a three-phase distributed winding motor or a concentrated winding motor having six phases (six poles), the space between the stator rotors of another small motor with respect to the space phase between the stator rotors of one small motor. The phase preferably has a phase angle difference of 30 degrees. In the case of a three-phase concentrated winding motor, the spatial phase between stator rotors of another small motor preferably has a phase angle difference of 60 degrees with respect to the spatial phase between stator rotors of one small motor. In this way, these two small motors can be regarded as a single motor having substantially twice the number of phases (poles), thereby reducing the cogging torque and reducing torque ripple and electromagnetic noise. it can.

  In a preferred embodiment, the motors have a common rotating shaft that protrudes in opposite directions. The two motor side gears are separately fixed to both ends of the common rotating shaft. The two motor side gears individually mesh with the two wheel side gears. According to this aspect, the radial space of the wheel can be effectively used for generating the motor torque, and the useless weight of the motor can be reduced.

  Since both ends of the rotating shaft have a torsional stress in the opposite direction, they can be made thin relative to the axial length. Moreover, the total physique weight of a motor can be reduced compared with the case where it drives with two motors. Furthermore, since the inertial mass per torque of the rotor rotating at a high speed can be reduced, a high-speed rotation speed change of the wheel can be realized. Further, since an idle space can be formed in the wheel in the radial direction of the wheel perpendicular to the rotation axis of the motor, the brake shoe of the disc brake and its drive mechanism can be accommodated in the idle space.

  In the second feature of the present invention, the inverter that exchanges AC power with the stator coil of the in-wheel motor device is built in the wheel. The inverter is supplied with DC power from a power source fixed to the vehicle body. In this way, since the inverter is built in the wheel, the AC power line from the inverter to the motor can be shortened, and as a result, the wiring inductance of the AC power line that is the output line of the inverter can be reduced. it can. Thereby, electromagnetic wave noise can be reduced.

  In the third feature of the present invention, the controller that controls the synchronous motor built in the left wheel and the synchronous motor built in the right wheel has a current-carrying phase to the left motor when the vehicle is traveling straight, The electrical phase to the motor is shifted by an electrical angle π. According to this aspect, since the torque ripples of the left and right motors can be in opposite phases when the vehicle is traveling straight, torque ripples and current ripples can be greatly reduced.

  In a preferred embodiment, the controller includes switching elements of the same homogenous arm of the left inverter that PWM-controls the inverter that drives the left motor and the right inverter that PWM-controls the right inverter that drives the right motor, Switching in reverse phase when the vehicle goes straight. If this mode is twisted, noise and current ripple due to PWM switching of the two inverters can be greatly reduced.

  In a fourth aspect of the present invention, the motor includes a soft magnetic rotor core that faces the stator core so as to be relatively rotatable with a small gap therebetween, and a magnet housing hole that penetrates the rotor core in the axial direction and accommodates a permanent magnet. And a high magnetic resistance flux barrier hole located on both sides in the circumferential direction of the magnet accommodation hole and penetrating in the axial direction, and a flux barrier filling portion made of an electrically insulating resin filled in the flux barrier hole.

  That is, in this aspect, the flux barrier hole of the rotor of the permanent magnet type synchronous machine is filled with an electrically insulating resin material. As the resin material, a so-called heat conductive resin is suitable. As the resin material, a resin having a high tensile strength is suitable. The resin material may contain a contaminant for improving thermal conductivity. This contaminant preferably has a high electrical resistance to reduce eddy current loss and must be non-magnetic to reduce magnetic flux shorts. According to the present invention, the following effects can be realized simultaneously.

  First, the flux barrier filling portion improves the centrifugal force resistance performance of the rotor, particularly the rotor core portion on the radially outer side of the permanent magnet embedded in the rotor core, so that the maximum rotational speed of the rotor and the high output of the motor are increased. Is realized. Next, in an in-wheel motor, particularly in a decelerating in-wheel motor sealed in a wheel, it is important to cool a permanent magnet built in the rotor. According to this aspect, the temperature rise of the rotor core and the permanent magnet due to the iron loss of the rotor core or the eddy current loss of the permanent magnet can be reduced.

  In a preferred embodiment, the rotor core has a protrusion that protrudes substantially circumferentially into the flux barrier hole. Thereby, the mechanical connectivity between the rotor core portion on the radially outer side of the permanent magnet and the flux barrier filling portion can be improved. More preferably, the protrusion protruding from the portion of the rotor core radially outside the permanent magnet (called the magnet outer core portion) into the flux barrier hole is the portion of the rotor core radially outside the permanent magnet (called the other core portion). ) Other than the protrusion protruding from the rotor core portion to the flux barrier hole. As a result, the centrifugal force of the magnet outer core portion is transmitted from the projection of the magnet outer core portion to the projection of the other core portion through the flux barrier filling portion, so that the centrifugal force resistance performance of the rotor core can be greatly improved. it can.

  In a fifth aspect of the present invention, the motor includes a soft magnetic rotor core that faces the stator core so as to be relatively rotatable with a small gap therebetween, and a magnet housing hole that penetrates the rotor core in the axial direction and houses a permanent magnet. And a high magnetic resistance flux barrier hole positioned on both sides in the circumferential direction of the magnet housing hole and penetrating in the axial direction, and a heat conductive member having good thermal conductivity penetrating the flux barrier hole or the magnet housing hole. This heat conducting member is in contact with both ends in the circumferential direction of the permanent magnet. The heat conducting member radiates heat to the air flow or the rotating shaft on both axial sides of the rotor.

According to this aspect, permanent demagnetization of the permanent magnet can be satisfactorily suppressed in a motor having a rotor with a permanent magnet embedded structure, particularly in a reduction type in-wheel motor sealed in a wheel.
In a preferred embodiment, the heat conducting member is constituted by a heat pipe. Thereby, a permanent magnet can be favorably cooled with a small heat conductive member.

1 is a schematic front view of a main part of a motor device according to a first embodiment. It is a typical principal part axial sectional view of the motor apparatus shown by FIG. FIG. 6 is a schematic cross-sectional view in the axial direction of a main part of a motor device of a second embodiment. It is a model principal part front view of the motor apparatus shown by FIG. It is a typical principal part axial sectional view of the in-wheel motor device of Embodiment 3. FIG. 6 is a schematic explanatory diagram of a motor device according to a fourth embodiment. FIG. 6 is a block circuit diagram of a motor device according to a fourth embodiment. It is a flowchart which shows the control operation of the motor apparatus shown by FIG. FIG. 8 is a schematic waveform diagram of U-phase current flowing in two inverters of the motor device shown in FIG. 7. It is a timing chart which shows the PWM control signal which makes the U1 phase upper arm switching element and the U2 phase upper arm switching element built in the inverter of the motor apparatus shown in FIG. 7 intermittent. FIG. 9 is a schematic radial half-sectional view showing a rotor of a motor device according to a fifth embodiment.

An in-wheel motor employing the motor device of the present invention will be described with reference to the following th example. In the drawings, RA means the radial direction of the wheel or motor, AX means the axial direction of the wheel or motor, and PH means the circumferential direction of the wheel or motor.
Example 1

The in-wheel motor of Embodiment 1 is demonstrated with reference to FIG.1 and FIG.2. FIG. 1 is a schematic front view of a main part of the in-wheel motor. FIG. 2 is a schematic sectional view in the axial direction of a main part of the in-wheel motor.
The motor 1 transmits torque to a wheel plate-like wheel side gear 2. The motor side gears (3 and 4) are fixed to the tips of the rotating shafts (5 and 6) protruding in the opposite direction from the motor 1. The wheel side gear 2 forms a reduction gear mechanism together with the motor side gears (3 and 4). The axis M of the stationary shaft (axle) fixed to the vehicle body is located at the center of the motor 1.

  A wheel plate-like wheel side gear 2 is rotatably supported on the stationary shaft. The axis of the wheel plate-like wheel side gear 2 coincides with the axis of the wheel. A gear surface 2 </ b> A is formed on one end surface of the wheel side gear 2. The motor side gears (3 and 4) mesh with the same gear surface 2 </ b> A of the wheel side gear 2. The rotation shafts (5 and 6) of the motor 1 rotate in the reverse direction at the same number of rotations. The number of teeth of the motor side gears (3 and 4) is made equal.

Details of the motor 1 will be described with reference to FIG. A stationary shaft 7 fixed to the vehicle body through a suspension device supports a wheel 8 rotatably. FIG. 2 illustrates the peripheral wall portion of the wheel 8. The rotating shafts (5 and 6) extend substantially horizontally.
In FIG. 2, a first motor 9 </ b> A and a second motor 9 </ b> B, which are small motors according to the present invention, are disposed in the motor housing 10. The first motor 9A and the second motor 9B are inner rotor type radial gap motors. Detailed description of the first motor 9A and the second motor 9B is omitted. The motor housing 10 is fixed to the stationary shaft 7. The wheel side gear 2 has a cylindrical portion fixed to the inner peripheral surface of the wheel 8.

  After all, in this embodiment, a plurality of small motors are accommodated radially in one wheel 8. Since these motors can have almost the same structure, manufacturing costs can be reduced by sharing parts. According to this embodiment, since a large reduction ratio can be realized with a simple structure, the maximum number of revolutions of the motor can be increased without using a complicated reduction mechanism. Further, since the diameter of the rotor of each small motor can be reduced, the total of their rotary inertia masses (inertia) can be reduced, and rapid stop and acceleration of the wheel are facilitated.

  Furthermore, the motor 1 is fixed to a stationary shaft 7 that extends in the axial direction at the axial center position M of the wheel 8 (see FIG. 2). A disk-shaped partition plate extends radially inward from the peripheral wall of the wheel 8. A mechanical seal is provided between the radially inner end of the partition plate and the outer peripheral surface of the stationary shaft 7. As a result, the motor 1 is well sealed in the wheel 8, so that a lubricant such as grease that lubricates the contact portion between the motor side gears (3 and 4) and the wheel side gear 2 leaks to the outside. There is no. Furthermore, it is possible to prevent dirty water and dust from entering the gear surface 2A from the outside.

(Modification)
In addition to the first motor 9A and the second motor 9B, a third motor (not shown) having the same shape may be added in different radial directions of the wheel 8. Preferably, the rotation shafts of the first motor 9A and the second motor 9B are arranged horizontally. The rotation axis of the third motor extends upward from the axis of the wheel 8.

  In one example, the first motor 9A and the second motor 9B configured by synchronous motors each receive three-phase AC power from one three-phase inverter (not shown). The circumferential relative position between the rotor and the stator of the first motor 9A (referred to as the inter-stator rotor phase) is the same as the circumferential relative position between the rotor and the stator of the second motor 9B. The two motor side gears mesh with the common wheel side gear. Thereby, the circuit and wiring including the inverter can be simplified.

  In another example, the first motor 9 </ b> A and the second motor 9 </ b> B configured by synchronous motors separately receive three-phase AC power from two three-phase inverters (not shown). The circumferential relative position between the rotor of the first motor 9A and the stator is deviated by 30 degrees or 60 degrees in electrical angle with respect to the circumferential relative position between the rotor of the second motor 9B and the stator. Similarly, the phase of the three-phase AC power transmitted by the two inverters is shifted by 30 degrees or 60 degrees in electrical angle. Thereby, torque ripple, cogging torque and electromagnetic noise of the in-wheel motor device are reduced.

(Embodiment 2)
The in-wheel motor apparatus of Embodiment 2 is demonstrated with reference to FIG.3 and FIG.4. FIG. 3 is a schematic sectional view in the axial direction of a main part of the motor device. FIG. 4 is a schematic front view of the main part of the motor device. This embodiment is characterized in that a single-rotor structure in-wheel motor having a common rotating shaft 5 is adopted as the motor 1 of the in-wheel motor device of Embodiment 1 shown in FIGS. 1 and 2. .

  Motor side gears (3 and 4) are individually fixed to both ends of the rotating shaft 5 of the motor 1. The motor side gear 4 is arranged farther away from the motor side gear 3 in the axial direction of the rotary shaft 5, that is, in the radial direction of the wheel 8. A wheel side gear 21 and a wheel side gear 22 as the wheel side gear 2 are fixed to the inner peripheral surface of the wheel 8. The gear surface 2 </ b> A of the wheel side gear 21 is disposed on the radially inner side of the wheel with respect to the gear surface 2 </ b> A of the wheel side gear 22. The gear surface 2A of the wheel side gear 21 is disposed on the opposite side in the axial direction with respect to the gear surface 2A of the wheel side gear 22 with the wheel side gears (21 and 22) interposed therebetween.

  The motor side gear 3 meshes with the wheel side gear 21. The motor side gear 4 meshes with the wheel side gear 22. The number of teeth of the wheel side gears (21 and 22) is made equal. The number of teeth of the motor side gears (3 and 4) is made equal. As a result, the teeth on the radially outer wheel side gear 22 and the motor side gear 4 are formed to be slightly larger than the teeth on the radially inner wheel side gear 21 and the motor side gear 3.

According to this aspect, torque can be applied to two points of the wheel 8 that are 180 degrees apart from each other by the single motor 1 arranged in the radial direction of the wheel 8. Since this embodiment uses a single motor, the motor structure becomes simple and the motor weight can be further reduced.
In this embodiment, a disk-shaped partition plate 12 for sealing the motor 1 extends radially inward from the inner peripheral surface of the wheel 8. The inner peripheral surface of the partition plate 12 is in contact with the outer peripheral surface of the stationary shaft 7 via a mechanical seal so as to be relatively rotatable. As a result, a sealed motor chamber is formed inside the in-wheel motor.

(Embodiment 3)
The in-wheel motor apparatus of Embodiment 3 is demonstrated with reference to FIG. FIG. 5 is a schematic sectional view in the axial direction of a main part of the motor device. M is the axis of the stationary shaft 7. MM is the axis of the motor 1.
In this in-wheel motor device, in the single motor type in-wheel motor device of the second embodiment, the distances of the motor side gears 3 and 4 from the axis M are made equal, and the motor side gears 3 and 4 have the same shape. The point has its characteristics.
Two wheel plate-like gear surfaces 2 </ b> A having the same shape are provided at both axial ends of the single wheel-side gear 23.

  The motor side gears 3 and 4 mesh with different gear surfaces 2A. The axis MM of the motor 1 is arranged obliquely at an angle θ with respect to the axis M of the wheel 8. Since the motor side gears 3 and 4 are prevented from meshing with the gear surface 2A on the side that should not mesh, the reduction gear mechanism can be simplified.

(Embodiment 4)
A motor device according to a fourth embodiment will be described with reference to FIGS. 6 and 7. This motor device incorporates the in-wheel motor device shown in FIGS. 1 and 2 in the left wheel and the right wheel. FIG. 6 is a schematic explanatory view of this motor device. FIG. 7 is a block circuit diagram of the motor device.
This motor device has a left in-wheel motor device 501 and a right in-wheel motor device 502. The in-wheel motor devices (501 and 502) are fixed to a stationary shaft 503 that is fixed to a vehicle body (not shown) and extends in the left-right direction. The in-wheel motor device 501 is built in the left wheel 505. The in-wheel motor device 502 is built in the right wheel 506.

The in-wheel motor device 501 has a motor M1. The in-wheel motor device 502 has a motor M2. The motor M1 and the motor M2 are supplied with AC power from an in-vehicle power source 504 through inverters (507 and 508). The in-vehicle power supply 504 supplies DC power to the inverters (507 and 508) through DC power supply lines (509 and 510).
The inverters (507 and 508) are arranged in a ring around the stationary shaft 503. The inverter 507 is built in the in-wheel motor device 501. The inverter 507 is fixed to the outer surface of the housing of the motor M1 fixed to the left end portion of the stationary shaft 503. The inverter 508 is built in the in-wheel motor device 502. The inverter 508 is fixed to the outer surface of the housing of the motor M2 fixed to the right end of the stationary shaft 503.

  The inverter 507 is supplied with power from the in-vehicle power supply 504 through a DC power supply line 509 that passes through the stationary shaft 503. The inverter 507 supplies three-phase AC power to the motor M1. The inverter 508 is supplied with power from the in-vehicle power supply 504 through a DC power supply line 510 that passes through the stationary shaft 503. Inverter 508 supplies three-phase AC power to motor M2. The motor M1 drives the wheel 505 of the in-wheel motor device 501. The motor M2 drives the wheel 506 of the in-wheel motor device 502.

  As shown in FIG. 7, the motor M1 is a three-phase synchronous motor having a three-phase stator coil S1 connected in a star shape. The motor M2 is a three-phase synchronous motor having a three-phase stator coil S2 connected in a star shape. The inverter 507 applies a three-phase AC voltage (U1, V1, and W1) to the three-phase stator coil S1. The inverter 508 applies a three-phase AC voltage (U2, V2, and W2) to the three-phase stator coil S2.

  The motor M1 has a rotation angle sensor 511. The motor M2 has a rotation angle sensor 512. The controller 5120 controls switching of the inverters 507 and 508. The controller 5120 controls the PWM switching operation of the inverters (507 and 508) based on the detected motor rotation angle, the value of the motor phase current, and the torque command value. The control operation of the controller for synchronous motor control is well known. The circuit configuration of the inverters (507 and 508), which are three-phase inverter circuits, and the PWM operation thereof are also well known.

  The inverter 507 energizes each phase coil of the stator coil S1 of the motor 1 separately with a three-phase current (Iu1, Iv1, and Iw1). The inverter 508 energizes each phase coil of the stator coil S1 of the motor 1 separately with a three-phase current (Iu2, Iv2, and Iw2). The three-phase currents (Iu1, Iv1, and Iw1) are phase currents that are 120 degrees out of phase with each other and have the same amplitude. The three-phase currents (Iu2, Iv2, and Iw2) are phase currents that are 120 degrees out of phase with each other and have the same amplitude.

  The control operation of the controller 512 will be described with reference to the flowchart shown in FIG. However, in the straight traveling state of the vehicle, the rotational speed of the motor M1 is equal to the rotational speed of the motor M2. First, it is determined from the information from the vehicle steering angle sensor (not shown) whether or not the straight traveling state has continued for a predetermined period or longer (S100). If no, the routine is terminated. If Yes, the current that the motor M1 energizes the stator coil S1 has a phase that is 180 degrees opposite to the current that the motor M2 energizes the stator coil S2 (S102).

That is, the U-phase current Iu2 of the motor M2 has a phase angle that is separated from the U-phase current Iu1 of the motor M1 by an electrical angle π. The V-phase current Iv2 of the motor M2 has a phase angle that is separated from the V-phase current Iv1 of the motor M1 by an electrical angle π. The W-phase current Iw2 of the motor M2 has a phase angle that is separated from the W-phase current Iw1 of the motor M1 by an electrical angle π.
The angular velocity and amplitude of the phase current Iu2 are equal to the angular velocity and amplitude of the transmission current Iu1. The angular velocity and amplitude of the phase current Iv2 are equal to the angular velocity and amplitude of the phase current Iv1. The angular velocity and amplitude of the phase current Iw2 are equal to the angular velocity and amplitude of the phase current Iw1.

  The waveforms of the phase current Iu1 and the phase current Iu2 are shown in FIG. As a result, the inverter 507 and the inverter 508 have an antiphase ripple current component. In FIG. 9, the + peak value of the phase currents (Iu1 and Iu2) corresponds to 80% PWM duty. The -peak value of the phase current (Iu1 and Iu2) corresponds to 20% PWM duty. A duty of 50% corresponds to an alternating current of 0V.

  However, abruptly performing the reverse phase control after detecting the vehicle straight running state increases the possibility of the synchronous motor stepping out. This problem is solved by gradually performing the reverse phase control. For example, when the phase angle difference between the phase currents (Iu1 and Iu2) is π + Δθ, the phase current Iu1 is gradually increased and the phase current Iu2 is gradually decreased. As a result, the rotational speed of the motor M1 is slightly increased. The rotational speed of the motor M2 is slightly reduced. Other phase currents are similarly controlled. After a predetermined time has elapsed, the phase currents (Iu1 and Iu2) are reversed, and this reversed phase state is maintained. That is, feedback control for converging the phase angle difference Δθ to 0 is executed slowly.

  Instead of setting the phases of the currents supplied to the two motors to be opposite in phase, it is possible to set the three-phase AC voltage applied to the two motors to be in opposite phases. That is, the phase of the voltage applied to the stator coil S1 is opposite to the phase of the voltage applied to the stator coil S2. However, the angular velocities and amplitudes of the phase voltages (Vu1 and Vu2) are equal. The angular velocities and amplitudes of the phase voltages (Vv1 and Vv2) are equal. The angular velocities and amplitudes of the phase voltages (Vw1 and Vw2) are equal. As a result, the inverter 507 and the inverter 508 have ripple voltage components having opposite phases. This voltage phase control is also performed gradually.

  Furthermore, the PWM intermittent timing of the in-phase arm (in-phase leg) of the inverters (507 and 508) is also reversed. That is, the switching element of the upper arm of the U1 phase leg of the inverter 507 is switched in reverse phase with respect to the switching element of the upper arm of the U2 phase leg of the inverter 508 (see FIG. 10). When the switching element of the upper arm of the U1 phase leg is turned on, the switching element of the upper arm of the U2 phase leg is turned off.

When the switching element of the upper arm of the U1 phase leg is turned off, the switching element of the upper arm of the U2 phase leg is turned on. Similarly, PWM switching is performed in the opposite phase in the other phases of the two inverters (507 and 508) and in the other arms (upper arm or lower arm).
As a result, the inverter 507 and the inverter 508 have PWM switching noise having an opposite phase. Thereby, torque ripple and noise can be reduced when the vehicle is traveling straight.

(Embodiment 5)
A preferred embodiment of an embedded permanent magnet synchronous motor (IPM) constituting the motor 1 will be described with reference to FIG. FIG. 11 is a schematic radial half sectional view showing the rotor of this IPM.
The rotor 33 is configured by laminating soft magnetic steel plates in the axial direction. The rotor 33 has a rotor core 331, a permanent magnet 332, and a flux barrier filling part 335. The soft magnetic rotor core 331 is fitted to the rotary shaft 5. The permanent magnet 332 is embedded in the rotor core 331.

  The rotor core 331 has a magnet housing groove 336 and a flux barrier hole 339. The magnet housing groove 336 extending in the axial direction passes through the rotor core 331. A permanent magnet 332 is accommodated in the magnet accommodation groove 336. The magnet housing groove 336 is arranged in a tangential direction at a position away from the axis of the rotating shaft 5 by a predetermined distance.

The magnet housing groove 336 includes a rotor core portion (hereinafter, referred to as a magnet outer core portion) 340A constituting a part of the radially outer rotor core portion, that is, a d-axis magnetic path, and a rotor core portion constituting a part of the q-axis magnetic path. 340 (hereinafter referred to as another core part).
The flux barrier hole 339 extends from the both ends in the circumferential direction of the magnet accommodation hole 336 toward the substantially outer side in the radial direction. The flux barrier hole 339 penetrates the rotor core 331 in the axial direction. The rotor core 331 includes a connecting portion 342 that is located on the outer side in the direction of the flux barrier hole 339 and connects the magnet outer core portion 340 </ b> A and the other core portion 340.

  The flux barrier filling portion 335 is formed of a resin containing filler that is filled and solidified in the flux barrier hole 339. Projections are formed on the peripheral edge of the rotor core 331 surrounding the flux barrier hole 339. The protrusion protruding from the magnet outer core portion 340 </ b> A to the flux barrier hole 339 is disposed radially inward from the protrusion protruding from the other core portion 340 to the flux barrier hole 339. Thereby, the centrifugal force acting on the magnet outer core portion 340A is transmitted to other core portions (particularly, the q-axis magnetic path portion) through these protrusions and the flux barrier filling portion 335.

The material constituting the flux barrier filling portion 335 is a resin material that is nonmagnetic, electrically insulating, and excellent in mechanical strength. Fillers such as short glass fibers can be mixed into the resin material.
Furthermore, in this embodiment, the heat pipe 350 is accommodated in the circumferential direction both ends of the magnet accommodation hole 336, respectively. The heat pipe 350 extends in the axial direction. The heat pipe 350 protrudes from both end surfaces of the rotor core 331 and is in close contact with a cooling blade (not shown). The cooling blades are fixed to both end surfaces of the rotor core 331. Thereby, the heat pipe 350 is cooled by the cooling blade.

  In addition, both ends of the heat pipe 350 are joined to metal disks fixed to both end surfaces of the rotor core 331. This metal disk is in close contact with the rotating shaft 5. Thereby, the heat of the heat pipe 350 is transmitted to the rotating shaft 5 through the metal disk. The heat pipe 350 is in close contact with both side surfaces of the permanent magnet 332. Thereby, the permanent magnet 332 is favorably cooled by the heat pipe 350.

  Reference numeral 1 denotes a motor. 2 is a wheel side gear. 2A is a gear surface. 3 is a motor side gear. Reference numeral 4 denotes a motor side gear. Reference numerals 5 and 6 denote rotation axes. 7 is a stationary shaft. 8 is a wheel. 9A and 9B are motors. Reference numeral 10 denotes a motor housing. Reference numeral 12 denotes a partition plate. 21 and 22 are wheel side gears.

Claims (12)

In a motor device having a motor built in a wheel of a vehicle that transmits and receives torque to and from the wheel, and a reduction gear mechanism that meshes with the rotating shaft of the motor and the wheel.
The reduction gear mechanism includes a cylindrical member fixed to the wheel inside the wheel, an outer peripheral portion of the end wall portion of the wheel or a ring-shaped wheel side gear fixed to the peripheral wall portion, and an end portion of the rotating shaft. A motor side gear fixed to the wheel side gear and meshing with the wheel side gear,
The motor is fixed to an axle that extends along the axis of the wheel and rotatably supports the wheel;
The rotating shaft extends in a substantially radial direction of the wheel,
The wheel has a partition plate extending radially inward from the peripheral wall portion of the wheel and reaching the axle,
The motor device, wherein the motor and the reduction gear mechanism are housed in the wheel sealed by the partition plate. The motor comprises a plurality of small motors each having a rotating shaft extending in a substantially different radial direction of the wheel and fixed to the axle,
The motor device according to claim 1, wherein the rotation shafts of the small motors mesh with the same wheel side gear through the motor side gears different from each other.   The motor device according to claim 2, wherein each of the small motors receives AC power from a common inverter. Each of the small motors receives AC power separately from a plurality of different inverters,
The motor device according to claim 2, wherein phases of the alternating currents output from the plurality of inverters are different from each other during straight traveling. The motor has the common rotating shaft protruding in opposite directions,
2. The motor device according to claim 1, wherein the two motor side gears are separately fixed to both ends of the common rotating shaft and individually meshed with the two wheel side gears. An inverter that exchanges AC power with the stator coil of the motor;
The motor device according to claim 1, wherein the inverter converts DC power supplied from a power source built in the wheel and fixed to a vehicle body into the AC power. The left motor comprising a synchronous motor built in the first wheel forming the left wheel;
The right motor comprising a synchronous motor built into the second wheel forming the right wheel;
A controller for controlling the two motors;
With
The controller shifts the plurality of phase currents constituting the stator current energized to the right motor by an electrical angle π when the vehicle goes straight with respect to the plurality of phase currents constituting the stator current energized to the left motor. The motor device according to claim 1.   The controller includes a switching element of the same homogenous arm of a left inverter that PWM-controls an inverter that drives the left motor and a right inverter that PWM-controls a right inverter that drives the right motor. The motor device according to claim 7, wherein the motor device performs switching with a reverse phase when traveling straight. The motor is
A soft magnetic rotor core facing the stator core so as to be relatively rotatable with a small gap therebetween;
A magnet housing hole that is penetrated in the rotor core in the axial direction and accommodates a permanent magnet;
A flux barrier hole having a high magnetic resistance located on both sides in the circumferential direction of the magnet housing hole and penetrating in the axial direction;
A flux barrier filling portion made of an electrically insulating resin filled in the flux barrier holes;
The motor device according to claim 1, comprising:   The motor device according to claim 9, wherein the rotor core has a protrusion that protrudes substantially circumferentially into the flux barrier hole. The motor is
A soft magnetic rotor core facing the stator core so as to be relatively rotatable with a small gap therebetween;
A magnet housing hole that is penetrated in the rotor core in the axial direction and accommodates a permanent magnet;
A flux barrier hole having a high magnetic resistance located on both sides in the circumferential direction of the magnet housing hole and penetrating in the axial direction;
A heat conductive member with good thermal conductivity penetrating the flux barrier hole or the magnet housing hole;
Have
The motor device according to claim 1, wherein the heat conducting member is in contact with both circumferential ends of the permanent magnet.   The motor device according to claim 11, wherein the heat conducting member is constituted by a heat pipe.

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