JP2019110726A - motor - Google Patents

Abstract

To accurately detect a position of a variable magnet.SOLUTION: An outer rotor 20 includes a plurality of variable magnets 25 of which magnetic force can be changed. A position of each variable magnet 25 is detected by two analog outer position sensors 45 whose output voltage varies linearly in accordance with a magnetic flux of each variable magnet 25. The two outer position sensors 45 are positioned apart from each other by an electric angle of 120 degrees.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a motor.

  A motor is conventionally known that includes a rotor magnet on the rotor side, and a variable magnet having a fixed magnet and a level of coercive force that is smaller than that of the fixed magnet and that can easily change the amount of magnetization. (See, for example, Patent Document 1).

  According to Patent Document 1, when low speed rotation and high output torque are required by passing an excitation current for changing the amount of magnetization of a variable magnet to a stator winding through an inverter circuit, the variable magnet Increase the amount of magnetization (increase magnetization) to increase the magnetic flux of the entire rotor magnet, but when high speed rotation and low output torque are required, decrease the amount of magnetization of the variable magnet (demagnetize) to reduce the rotor An arrangement is disclosed that reduces the magnetic flux across the magnet.

Patent No. 5121623 gazette

  By the way, in order to change the magnetization amount of the variable magnet, when the excitation current is supplied to the variable magnet, it is necessary to accurately detect the position of the variable magnet. Therefore, it is conceivable to use, as the position sensor, a digital hall sensor that can obtain ON / OFF switching output according to the strength of the magnetic force.

  However, when demagnetizing the magnetic force of the variable magnet, the edge position at which the switching output of the Hall sensor switches, that is, the boundary position of whether or not the variable magnet is present can not be accurately grasped. There is a possibility that the false detection of the position of may occur.

  The present invention has been made in view of the foregoing, and an object thereof is to enable accurate detection of the position of a variable magnet.

  The present invention is directed to a motor having a stator having a three-phase coil and a rotor rotatable relative to the stator, and has taken the following solution.

That is, in the first invention, the rotor has a plurality of variable magnets capable of changing the magnetic force,
A control unit configured to control an energization operation of the coil so as to increase or decrease the magnetic force of the variable magnet;
And at least two analog position sensors whose output voltage changes linearly according to the magnetic flux of the variable magnet,
The adjacent position sensors are characterized in that they are disposed at an electrical angle of 120 ° or 90 ° apart.

  In the first invention, at least two analog position sensors are provided to detect the position of the variable magnet. As described above, by using the analog type position sensor, even when the magnetic force of the variable magnet is demagnetized, the output voltage of the position sensor linearly changes in accordance with the magnetic flux of the variable magnet. As a result, it is possible to suppress erroneous detection of the position of the variable magnet without losing sight of the boundary position of whether or not the variable magnet is present.

  Adjacent position sensors are disposed at an electrical angle of 120 ° or 90 ° apart. Thereby, the position of the variable magnet can be detected by at least one of the adjacent position sensors, and the position detection accuracy of the variable magnet can be enhanced.

A second invention relates to the first invention,
The adjacent position sensors are disposed at an electrical angle of 120 ° apart,
When the width of the variable magnet is 120 ° or more, the control unit causes the coil to perform magnetization by two-phase energization within a predetermined range from one end of the variable magnet in the circumferential direction. And controlling the energization operation of the circuit.

  In the second invention, adjacent position sensors are arranged at an electrical angle of 120 ° apart. Then, when the width of the variable magnet is 120 ° or more in electrical angle, within a predetermined range from one end of the variable magnet in the circumferential direction, magnetization is performed by two-phase energization.

  As a result, it is possible to eliminate the problem that occurs when one end of the variable magnet is magnetized in a single phase.

  Specifically, when one end of the variable magnet is magnetized by flowing a magnetic flux from the W phase teeth toward the variable magnet among the U phase, V phase and W phase, the U phase and V from the rotor side The magnetic flux is diverted toward the phase teeth. At this time, since the width of the variable magnet is 120 ° or more in electrical angle, the other end of the variable magnet faces the V-phase teeth. Therefore, the other end of the variable magnet is demagnetized by the magnetic flux from the rotor side toward the V-phase teeth.

  Therefore, in the present invention, within a predetermined range from one end of the variable magnet in the circumferential direction, magnetization is performed by two-phase energization. Specifically, the magnetic flux flowing from the W phase teeth toward one end of the variable magnet is controlled to flow from the rotor side to the U phase teeth. That is, since the flow of magnetic flux does not occur between the other end of the variable magnet and the V-phase teeth, the other end is not demagnetized when the one end of the variable magnet is magnetized.

A third aspect of the invention relates to the first or second aspect of the invention.
The control unit controls the current supplying operation to the coil so as to rotate the rotor in one direction and to magnetize a front portion in the rotation direction of the variable magnet while the rotor is rotating. It is a thing.

  In the third invention, during rotation of the rotor, the front portion in the rotational direction of the variable magnet is magnetized. Thereby, the variable magnet can be attracted in the direction to accelerate the rotation of the rotor to reduce the magnetization noise.

  Specifically, when the variable magnet of the rotor is the S pole, the magnetic flux flows in the same direction as the magnetic flux flowing through the inside of the variable magnet, that is, in the direction from the teeth toward the variable magnet Magnetize the part.

  On the other hand, when the variable magnet of the rotor has N poles, the magnetic flux flows in the same direction as the magnetic flux flowing through the inside of the variable magnet, that is, in the direction from the variable magnet toward the teeth. Magnetize.

  Thereby, when the variable magnet is magnetized, a suction force is exerted between the front portion of the variable magnet in the rotation direction and the teeth, and the rotor is accelerated in the rotation direction, so that the magnetization noise can be reduced. .

The fourth invention is the third invention,
The control unit controls the energization operation to the coil so as to rotate the rotor in a direction opposite to one direction and to magnetize a front portion in a rotational direction of the variable magnet while the rotor is rotating. It is characterized by

  In the fourth invention, during the reverse rotation of the rotor, the front portion in the rotational direction of the variable magnet is magnetized. That is, after rotating the rotor in one direction and magnetizing the front portion of the variable magnet, the rotor is rotated reversely to magnetize the remaining rear portion in the same manner. As a result, when the entire variable magnet is magnetized, it is possible to attract the variable magnet in a direction that accelerates the rotation of the rotor and reduce the magnetization noise.

According to a fifth aspect of the invention, in any one of the first to fourth aspects,
The control unit controls the energization operation to the coil so as to rotate the rotor in one direction and to demagnetize a rear portion in the rotation direction of the variable magnet while the rotor is rotating. It is

  In the fifth invention, during rotation of the rotor, the rear portion in the rotational direction of the variable magnet is demagnetized. Thereby, the variable magnet can be attracted in the direction to accelerate the rotation of the rotor to reduce the magnetization noise.

  Specifically, when the variable magnet of the rotor is the S pole, the magnetic flux flows in the direction opposite to the magnetic flux flowing through the inside of the variable magnet, that is, in the direction from the variable magnet toward the teeth. Demagnetize the side part.

  On the other hand, when the variable magnet of the rotor has N poles, the magnetic flux flows in the direction opposite to the magnetic flux flowing inside the variable magnet, that is, in the direction from the teeth toward the variable magnet. Demagnetize the part.

  Thereby, when demagnetizing the variable magnet, a repulsive force acts between the rear side portion of the variable magnet in the rotation direction and the teeth, and the rotor is accelerated in the rotation direction, so that the magnetization noise can be reduced. it can.

The sixth invention is the fifth invention,
The control unit controls the energization operation to the coil so as to rotate the rotor in a direction opposite to one direction and to demagnetize the rear portion in the rotation direction of the variable magnet while the rotor is rotating. It is characterized by doing.

  In the sixth invention, during the reverse rotation of the rotor, the rear portion in the rotational direction of the variable magnet is demagnetized. That is, after the rotor is rotated in one direction to demagnetize the rear portion of the variable magnet, the rotor is reversely rotated to demagnetize the remaining front portion in the same manner. As a result, when the entire variable magnet is demagnetized, the variable magnet can be repelled in the direction to accelerate the rotation of the rotor to reduce the magnetization noise.

A seventh invention relates to any one of the first to sixth inventions,
The control unit controls the energization operation to the coil so as to make the magnetic force of the variable magnet substantially uniform when the variation of the magnetic force among the plurality of variable magnets is larger than a predetermined reference value. It is characterized by

  In the seventh invention, when the variation of the magnetic force among the plurality of variable magnets is larger than a predetermined reference value, the magnetic force is changed so that the magnetic force of the variable magnet becomes substantially uniform. Thereby, the noise resulting from the imbalance of the magnetic force of a variable magnet can be suppressed.

The eighth invention is the seventh invention,
The controller magnetizes the variable magnet having a smaller magnetic force than a predetermined value when increasing the magnetic force of the variable magnet, while decreasing the magnetic force of the variable magnet when reducing the magnetic force of the variable magnet. Is controlled so as to demagnetize the variable magnet.

  In the eighth invention, the magnetic force is increased as a whole by magnetizing the variable magnet having a small magnetic force, while the magnetic force is reduced as a whole by demagnetizing the variable magnet having a large magnetic force. Thereby, equalization | homogenization of the magnetic force of several variable magnets can be performed efficiently.

  According to the present invention, the position of the variable magnet can be accurately detected.

It is a side sectional view showing the composition of the washing machine concerning this embodiment. It is a top view which shows the whole structure of a motor. It is a top view which shows the principal part of a motor. It is a figure explaining the difference of the output of an analog type and a digital type position sensor. It is a figure explaining the flow of the magnetic flux at the time of three-phase electricity supply. It is a figure explaining the flow of the magnetic flux at the time of two-phase electricity supply. It is a figure explaining the timing which magnetizes the variable magnet of S pole. It is a figure explaining the timing which magnetizes the variable magnet of N pole. It is a figure explaining the timing which demagnetizes the variable magnet of S pole. It is a figure explaining the timing which demagnetizes the variable magnet of N pole. It is a figure which shows the waveform of an induced voltage when the magnetic force of several variable magnets has disperse | distributed. It is a graph which shows the relationship between a frequency and a noise level when the magnetic force of several variable magnets is disperse | distributed. It is a figure which shows the waveform of induced voltage when the magnetic force of several variable magnets is equalized. It is a graph which shows the relation of frequency and a noise level when the magnetic force of a plurality of variable magnets is equalized.

  Hereinafter, embodiments of the present invention will be described based on the drawings. The following description of the preferred embodiments is merely illustrative in nature, and is not intended to limit the present invention, its applications, or its applications.

<Whole machine configuration>
The washing machine 1 of this embodiment is shown in FIG. The washing machine 1 is a fully automatic washing machine in which each process of washing to rinsing and dewatering can be performed by automatic control.

  The washing machine 1 has a rectangular box-like housing 2, and a circular insertion opening 4 opened and closed by a door 3 is formed on the front surface of the washing machine 1. The loading and unloading of the laundry is performed through the inlet 4.

  An operation unit 5 in which a switch or the like is disposed is installed at the upper front of the housing 2, and a controller 6 (control unit) is built in the rear of the operation unit 5. Inside the housing 2, a water tank 10, a drum 11, a motor 16, a pulsator 12 and the like are disposed.

  The water tank 10 is a bottomed cylindrical container having an opening 10a having a diameter smaller than the inner diameter at one end, and is horizontally disposed so that the opening 10a faces the inlet 4 and the center line extends in the substantially horizontal direction. It is installed in the inside of case 2 in the state where At the time of washing and rinsing, wash water and rinse water are stored in the lower part of the water tank 10.

  The drum 11 is a bottomed cylindrical container having an opening 11a at one end and a bottom at the other end, and is accommodated in the water tank 10 with the opening 11a facing forward. The drum 11 is rotatable about a rotation axis J extending in the front-rear direction, and in a state where the laundry is accommodated in the drum 11, each stroke such as washing, rinsing, and dewatering is performed.

  A large number of water passage holes 11 b penetrating to the inside and outside are formed in the peripheral wall portion of the drum 11, and the washing water stored in the water tank 10 flows into the inside of the drum 11 through the water passage holes 11 b.

  The pulsator 12 is disposed at the bottom of the drum 11. The pulsator 12 is rotatable about the rotation axis J independently of the drum 11.

  A double shaft 15 consisting of an inner shaft 13 and an outer shaft 14 is installed in a state of penetrating the bottom of the water tank 10 with the rotation axis J at the center. The outer shaft 14 is a cylindrical shaft having an axial length shorter than that of the inner shaft 13.

  The inner shaft 13 is rotatably supported inside the outer shaft 14, and the pulsator 12 is connected to and supported by the tip of the inner shaft 13. The outer shaft 14 is rotatably supported by the water tank 10, and the drum 11 is connected to and supported by the tip of the outer shaft 14. The proximal ends of the outer shaft 14 and the inner shaft 13 are connected to a motor 16 disposed on the rear side of the water tank 10.

  The motor 16 has a flat cylindrical outer shape whose diameter is smaller than that of the water tank 10, and is assembled on the rear side of the water tank 10. The motor 16 drives each of the outer shaft 14 and the inner shaft 13 independently. The controller 6 is configured by hardware such as a CPU and a memory, and software such as a control program. The controller 6 controls the washing machine 1 comprehensively, and automatically operates each process such as washing, rinsing and dewatering in accordance with an instruction input from the operation unit 5.

<motor>
As shown in FIG. 2, the motor 16 is configured of an outer rotor 20, an inner rotor 30, a stator 40, and the like. That is, the motor 16 is a so-called dual rotor motor provided with the outer rotor 20 and the inner rotor 30 radially outward and inward of one stator 40.

  The outer rotor 20 and the inner rotor 30 are connected to the pulsator 12 and the drum 11 without interposing a clutch or an acceleration / deceleration machine, and are configured to directly drive these.

  The outer rotor 20 and the inner rotor 30 share the coil 43 of the stator 40, and by supplying a current to the coil 43, the motor 16 rotationally drives each of the outer rotor 20 and the inner rotor 30 independently. It can be done.

  The outer rotor 20 is a flat bottomed cylindrical member and has a rotor yoke 22 erected at the periphery of the bottom and a plurality of outer magnets 24 formed of arc-shaped permanent magnets.

  In the present embodiment, the outer rotor 20 is a consistent type rotor, and 16 outer magnets 24 are arranged so that S poles and N poles are alternately arranged at intervals in the circumferential direction. It is fixed to the inner surface. In addition, although mentioned later in detail, the outer magnet 24 is comprised by the variable magnet 25 which can magnetize or demagnetize a magnetic force by controlling the electricity supply operation | movement to the coil 43. As shown in FIG.

  The inner rotor 30 is a flat bottomed cylindrical member having an outer diameter smaller than that of the outer rotor 20, and has a plurality of inners composed of an inner peripheral wall 32 standing around the bottom and a rectangular plate-shaped permanent magnet. And a magnet 34.

  In the present embodiment, the inner rotor 30 is a spoke-type rotor, and 32 inner magnets 34 are arranged to be radially arranged at intervals in the circumferential direction, and are attached and fixed to the inner peripheral wall portion 32. . The rotor core 33 is disposed between the inner magnets 34 in the circumferential direction.

  The stator 40 is formed of an annular member having an outer diameter smaller than the inner diameter of the outer rotor 20 and larger in inner diameter than the outer diameter of the inner rotor 30. The stator 40 is provided with a plurality of teeth 41 and coils 43 embedded in a resin. The stator 40 of the present embodiment is provided with 24 I-shaped teeth 41 and coils 43.

  The teeth 41 are thin-plate iron members whose longitudinal cross section has an I shape, and are arranged all around the stator 40 so that they are arranged radially at equal intervals. The side end portions on the inner peripheral side and the outer peripheral side of the teeth 41 protrude in a bowl shape in the circumferential direction from both corners thereof.

  A coil 43 is formed for each tooth 41 by continuously winding three wires coated with an insulating material through an insulating material in a predetermined order and configuration to the teeth 41. A group of teeth 41 on which the coil 43 is formed is embedded in a thermosetting resin by molding in a state in which only each end face on the diameter side is exposed, and fixed in a fixed arrangement in an insulated state .

  The end of the tooth 41 on the inner rotor 30 side is opposed to the rotor core 33 with a slight gap, and the end of the tooth 41 on the outer rotor 20 side is opposed to the outer magnet 24 with a slight gap. The stator 40, the inner rotor 30, and the outer rotor 20 are assembled.

  A digital inner side position sensor 44 is disposed at a position near the inner rotor 30 between the adjacent teeth 41. The inner side position sensor 44 is for grasping the position of the inner rotor 30.

  Further, an analog outer side position sensor 45 is disposed at a position near the outer rotor 20 between the adjacent teeth 41. The outer side position sensor 45 is, for example, a Hall sensor, and is for grasping the position of the inner rotor 30.

  In the motor 16 according to the present embodiment, when the coil 43 of the stator 40 is energized, different poles are simultaneously generated on the outer side and the inner side of the teeth 41, and along with the rotating magnetic field, the outer rotor 20 and The inner rotors 30 rotate independently of one another.

  Thus, the stator 40 can be shared by the outer rotor 20 and the inner rotor 30, and the outer rotor 20 and the inner rotor 30 can be rotationally driven in a plurality of rotation modes by one inverter.

  FIG. 3 is a plan view showing the main part of the motor, showing a state of 90 ° mechanical angle. The outer magnets 24 are all composed of variable magnets 25. The inner magnets 34 are all configured by fixed magnets 35. Here, the variable magnet 25 is a magnet whose magnetic force can be changed when a magnetizing current is supplied to the coil 43. The fixed magnet 35 is a magnet whose magnetic force does not change even if a magnetizing current is supplied to the coil 43.

  The controller 6 controls the energization operation to the coil 43 to flow a magnetic flux to the variable magnet 25 so as to magnetize or demagnetize the magnetic force of the variable magnet 25. Here, in order to flow a magnetic flux to the variable magnet 25, it is necessary to accurately detect the position of the variable magnet 25. Therefore, in order to detect the position of the variable magnet 25 of the outer rotor 20, two outer position sensors 45 are provided.

  Specifically, the two outer position sensors 45 are arranged at an electrical angle of 120 ° apart. The outer position sensor 45 is an analog Hall sensor whose output voltage changes linearly in accordance with the magnetic flux of the variable magnet 25.

  As described above, even when the magnetic force of the variable magnet 25 is demagnetized by using the analog outer side position sensor 45, the output voltage of the outer side position sensor 45 changes linearly according to the magnetic flux of the variable magnet 25. (See FIG. 4). As a result, it is possible to suppress erroneous detection of the position of the variable magnet 25 without losing sight of the boundary position as to whether or not the variable magnet 25 is present.

  Further, since the two outer side position sensors 45 are disposed at an electrical angle of 120 ° apart, at least one of the two outer side position sensors 45 detects the position of the variable magnet 25, and the variable magnet 25 is detected. Position detection accuracy can be improved.

  Further, two inner side position sensors 44 for detecting the position of the inner magnet 34 are arranged at an electrical angle of 120 ° apart. The inner side position sensor 44 is configured by a digital hall sensor that can obtain ON / OFF switching output according to the strength of the magnetic force.

<About 2-phase energization>
As shown in FIG. 5, inside the variable magnet 25, magnetic flux flows from the S pole to the N pole. Therefore, when the magnetic force of the variable magnet 25 is increased, if the variable magnet 25 facing the teeth 41 is the S pole, the magnetic flux flowing through the inside of the variable magnet 25 is in the same direction as the magnetic flux, that is, from the teeth 41 to the variable magnet 25. It suffices to control the energization operation to the coil 43 so that the magnetic flux flows.

  On the other hand, when the variable magnet 25 opposed to the teeth 41 has N pole, the energizing operation to the coil 43 so that the magnetic flux flows from the variable magnet 25 toward the teeth 41 in the same direction as the magnetic flux flowing inside the variable magnet 25 Should be controlled.

  By the way, of U-phase, V-phase and W-phase, one end portion (right end portion in FIG. 5) of the S-pole variable magnet 25 is caused by flowing magnetic flux from the W-phase tooth 41 to the S-pole variable magnet 25. When the magnetization is increased, the magnetic flux is divided from the outer rotor 20 to the U-phase and V-phase teeth 41 respectively. At this time, since the width of the variable magnet 25 is 120 ° in electrical angle, the other end (left end in FIG. 5) of the variable magnet 25 faces the teeth 41 of the V phase. Therefore, the other end (the left end in FIG. 5) of the variable magnet 25 is demagnetized by the magnetic flux from the outer rotor 20 to the V-phase teeth 41.

  Therefore, in the present embodiment, when the width of the variable magnet 25 is an electrical angle of 120 ° or more, within a predetermined range from one end of the variable magnet 25 in the circumferential direction, magnetization is performed by two-phase energization. .

  Specifically, the energization to the V-phase coil 43 is stopped, and as shown in FIG. 6, the W-phase teeth 41 move toward the one end (right end in FIG. 6) of the S-pole variable magnet 25. The flowed magnetic flux is controlled to flow toward the U-phase teeth 41 through the N-pole variable magnet 25. At this time, the N-pole variable magnet 25 is also magnetized.

  As described above, since no flow of magnetic flux occurs between the other end (left end in FIG. 6) of the variable magnet 25 and the V-phase tooth 41, one end (right end in FIG. 6) of the variable magnet 25 Is not demagnetized at the other end (left end in FIG. 6) of the variable magnet 25 facing the V-phase teeth 41. Thereby, the entire variable magnet 25 can be magnetized.

<About the timing of magnetization or demagnetization>
As shown in FIGS. 7 to 10, in the present embodiment, when the magnetic force of the variable magnet 25 is magnetized or demagnetized, the rotational direction of the outer rotor 20 and the position of the variable magnet 25 are considered.

  First, as shown in FIG. 7, the case where the outer rotor 20 is rotating in one direction (left direction in FIG. 7) and the variable magnet 25 of the S pole facing the teeth 41 is magnetized will be examined.

  In this case, while the outer rotor 20 is rotating, magnetic flux is flowed from the teeth 41 toward the front portion (left portion in FIG. 7) of the variable magnet 25 in the rotational direction to magnetize the left portion of the variable magnet 25 Do. Thereby, when the variable magnet 25 is magnetized, a suction force is exerted between the left portion of the variable magnet 25 and the teeth 41, and the outer rotor 20 is accelerated in the rotation direction, thereby reducing the magnetization noise. Can.

  In the remaining right side portion (the rear side portion in the rotational direction in FIG. 7) after the left side portion of the variable magnet 25 is magnetized, the outer rotor 20 is reversely rotated to be similarly magnetized. There is.

  That is, while the outer rotor 20 is reversely rotating, magnetic flux is flowed from the teeth 41 toward the front portion (right side portion in FIG. 7) in the reverse rotation direction of the variable magnet 25 to magnetize the right portion of the variable magnet 25 . As a result, when the variable magnet 25 is magnetized, a suction force is exerted between the right side portion of the variable magnet 25 and the teeth 41, and the outer rotor 20 is accelerated in the reverse rotation direction, thereby reducing the magnetization noise. be able to.

  FIG. 8 shows the flow of magnetic flux when the outer rotor 20 rotates in one direction (left direction in FIG. 8) and the N-pole variable magnet 25 facing the teeth 41 is magnetized.

  As shown in FIG. 8, while the outer rotor 20 is rotating, the left side portion of the variable magnet 25 is moved by flowing a magnetic flux from the front side portion (left side portion in FIG. 8) of the variable magnet 25 in the rotational direction toward the teeth 41. Magnetize. Thereby, when the variable magnet 25 is magnetized, a suction force is exerted between the left portion of the variable magnet 25 and the teeth 41, and the outer rotor 20 is accelerated in the rotation direction, thereby reducing the magnetization noise. Can.

  The outer rotor 20 may be reversely rotated to magnetize in the same manner for the remaining right side portion (rear side portion in the rotation direction in FIG. 8) after the left side portion of the variable magnet 25 is magnetized.

  Next, as shown in FIG. 9, the case where the outer rotor 20 rotates in one direction (left direction in FIG. 9) and the demagnetizing of the S-pole variable magnet 25 facing the teeth 41 will be examined.

  In this case, while the outer rotor 20 is rotating, the right side portion of the variable magnet 25 is reduced by flowing magnetic flux from the rear portion (right side portion in FIG. 9) of the variable magnet 25 in the rotational direction Magnetize. Thereby, when the variable magnet 25 is demagnetized, a repulsive force is exerted between the right side portion of the variable magnet 25 and the teeth 41 to accelerate the outer rotor 20 in the rotational direction, thereby reducing the magnetization noise. Can.

  The outer rotor 20 may be reversely rotated to demagnetize the remaining left portion (the front portion in the rotational direction in FIG. 9) after the demagnetization of the right portion of the variable magnet 25.

  FIG. 10 shows the flow of magnetic flux in the case where the outer rotor 20 rotates in one direction (left direction in FIG. 10) and the N-pole variable magnet 25 facing the teeth 41 is demagnetized.

  As shown in FIG. 10, while the outer rotor 20 is rotating, the magnetic flux is allowed to flow from the teeth 41 toward the rear portion (right side portion in FIG. 10) of the variable magnet 25 in the rotational direction. Demagnetize Thereby, when the variable magnet 25 is demagnetized, a repulsive force is exerted between the right side portion of the variable magnet 25 and the teeth 41 to accelerate the outer rotor 20 in the rotational direction, thereby reducing the magnetization noise. Can.

  The outer rotor 20 may be reversely rotated and demagnetization is similarly performed for the remaining left side portion (front side portion in the rotation direction in FIG. 10) after demagnetization of the right side portion of the variable magnet 25.

<Uniformization of the magnetic force of the variable magnet>
An imbalance of magnetic force may occur between the plurality of variable magnets 25. Then, if the outer rotor 20 is rotated at high speed in a state where the magnetic force of the variable magnet 25 is dispersed, the vibration accompanying the high speed rotation of the outer rotor 20 becomes large, and noise is generated.

  Therefore, in the present embodiment, the energization operation to the coil 43 is controlled so that the magnetic forces of the plurality of variable magnets 25 become substantially uniform.

  As shown in FIG. 11, the magnetic force of the variable magnet 25 can be determined by measuring the induced voltage generated when the outer rotor 20 is rotated. In FIG. 11, by feeding back the output signal of the outer side position sensor 45, the induced voltage is shaped into a sine wave.

  Looking at the waveform of the induced voltage in FIG. 11, the amplitude of the induced voltage is larger in the amplitude B than in the amplitude A. This indicates that the magnetic force of the variable magnet 25 is large if the amplitude of the induced voltage is large, and the magnetic force of the variable magnet 25 is small if the amplitude of the induced voltage is small.

  Then, when the outer rotor 20 is rotated in a state where the magnetic force of the variable magnet 25 is dispersed, as shown in FIG. 12, the noise level is 1.5 times the frequency (1.5f component) of the rotation speed of the motor 16. You can see that it is getting bigger.

  Therefore, when the variation of the magnetic force among the plurality of variable magnets 25 is larger than a predetermined reference value, the magnetic force of the variable magnet 25 is increased or decreased so as to make the magnetic force of the variable magnet 25 substantially uniform. It is like that.

  Specifically, when the magnetic force of the variable magnet 25 as a whole is reduced, the variable magnet 25 whose magnetic force is larger than a predetermined value is demagnetized. That is, in the example shown in FIG. 11, the magnetic force is changed to approach the amplitude A by demagnetizing the variable magnet 25 of the amplitude B of the induced voltage. As a result, as shown in FIG. 13, the induced voltage can be made substantially uniform to the amplitude A, and the magnetic forces of the plurality of variable magnets 25 can be made substantially uniform.

  Here, as shown in FIG. 14, if the magnetic forces of the plurality of variable magnets 25 are made substantially uniform, the noise level becomes small at a frequency 1.5 fps (1.5 f component) of the rotational speed of the motor 16. I understand that

  In order to increase the magnetic force of the variable magnet 25 as a whole, the variable magnet 25 smaller than a predetermined value may be magnetized. That is, in the example shown in FIG. 11, the magnetic force may be changed to approach the amplitude B by magnetizing the variable magnet 25 of the amplitude A of the induced voltage.

<< Other Embodiments >>
The above embodiment may be configured as follows.

  In this embodiment, the magnetic force of the outer rotor 20 can be changed by providing the variable magnet 25 on the outer rotor 20, but the magnetic force of the inner rotor 30 can be changed by providing the variable magnet 25 on the inner rotor 30. It is also good.

  Moreover, although the structure which provided two outer side position sensors 45 was demonstrated in this embodiment, you may provide two or more. Further, although the adjacent outer side position sensors 45 are disposed at an electrical angle of 120 ° apart, for example, the adjacent outer side position sensors 45 may be disposed at an electrical angle of 90 ° apart.

  Further, in the present embodiment, although the magnitude of the magnetic force of the variable magnet 25 is detected based on the amplitude of the induced voltage, for example, the magnetic force of the variable magnet 25 is detected by providing a magnetic flux sensor. It is also good.

  As described above, the present invention is extremely useful and has high industrial applicability because a highly practical effect of being able to accurately detect the position of the variable magnet is obtained.

6 Controller (control unit)
16 Motor 20 Outer rotor (rotor)
25 variable magnet 40 stator 43 coil 45 outer side position sensor (position sensor)

Claims (8)

A motor comprising: a stator having a three-phase coil; and a rotor rotatable relative to the stator,
The rotor has a plurality of variable magnets capable of changing the magnetic force,
A control unit configured to control an energization operation of the coil so as to increase or decrease the magnetic force of the variable magnet;
And at least two analog position sensors whose output voltage changes linearly according to the magnetic flux of the variable magnet,
A motor, wherein the position sensors adjacent to each other are disposed at an electrical angle of 120 ° or 90 ° apart. In claim 1,
The adjacent position sensors are disposed at an electrical angle of 120 ° apart,
When the width of the variable magnet is 120 ° or more, the control unit causes the coil to perform magnetization by two-phase energization within a predetermined range from one end of the variable magnet in the circumferential direction. A motor characterized by controlling the energizing operation of the motor. In claim 1 or 2,
The control unit controls the current supplying operation to the coil so as to rotate the rotor in one direction and to magnetize a front portion in the rotation direction of the variable magnet while the rotor is rotating. motor. In claim 3,
The control unit controls the energization operation to the coil so as to rotate the rotor in a direction opposite to one direction and to magnetize a front portion in a rotational direction of the variable magnet while the rotor is rotating. A motor characterized by In any one of claims 1 to 4,
The control unit controls the energization operation to the coil so as to rotate the rotor in one direction and to demagnetize a rear portion in the rotation direction of the variable magnet while the rotor is rotating. Motor. In claim 5,
The control unit controls the energization operation to the coil so as to rotate the rotor in a direction opposite to one direction and to demagnetize the rear portion in the rotation direction of the variable magnet while the rotor is rotating. A motor characterized by In any one of claims 1 to 6,
The control unit controls the energization operation to the coil so as to make the magnetic force of the variable magnet substantially uniform when the variation of the magnetic force among the plurality of variable magnets is larger than a predetermined reference value. A motor characterized by In claim 7,
The controller magnetizes the variable magnet having a smaller magnetic force than a predetermined value when increasing the magnetic force of the variable magnet, while decreasing the magnetic force of the variable magnet when reducing the magnetic force of the variable magnet. A motor, characterized in that the energization operation to the coil is controlled so as to demagnetize the variable magnet.

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