JP2020036492A - motor - Google Patents

Abstract

To provide a motor which can use an IC by adjusting an assembled angle of the IC, when the IC housing an element which detects a rotational phase of a rotor within a single package is arranged and even when the IC is diverted for a motor with a different diameter and a different pole number of the rotor.SOLUTION: A motor has: a first yoke 6 having a rotatable rotor 3 with a magnet composed of a first magnetized layer 2A and a second magnetized layer 2B multi-polarized at a pitch C alternately in a different pole in an n-divided circumferential direction, a first coil 4, a second coil 5, and a first magnetic pole portion 6a; a second york 7 having a second magnetic pole portion 7a; and detection means for detecting a rotational phase of the magnet, and having a first detection element 10a and a second detection element 10b arranged at a pitch L. The first detection element is arranged in a magnetic pole center position of the magnetized layer and the second detection element is arranged in a position at a switchover of the magnetic pole of the magnetized layer.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a motor provided with position detecting means.

  The stepping motor has features such as small size, high torque, and long life, and digital positioning operation can be easily realized by open loop control. For this reason, it is widely used for information home appliances such as cameras and optical disk devices, and OA devices such as printers and projectors.

  However, when the motor is rotating at high speed, when the load on the motor is large, or when trying to rotate at high speed, there is a problem that the motor loses synchronism and a problem that the efficiency is lower than that of the brushless motor or DC motor. Was.

  In order to solve this problem, it is known to prevent loss of synchronism by attaching an encoder to a stepping motor and switching the energization in accordance with the position of the rotor, that is, by operating a so-called brushless DC motor (Patent Document 1). And 2). This covers the rising delay of the current by switching the current flowing through the coil by a signal obtained by advancing the signal obtained by the non-contact type sensor built in the motor according to the speed, and enables high-speed operation. .

  FIG. 9 shows the torque acting on the rotor when a constant current is applied to the coils of the motors disclosed in Patent Documents 1 and 2. Since a forward current and a reverse current can be passed through each of the two coils, four types of torque curves appear. Each of them has a substantially sinusoidal waveform, and has a phase difference of 90 ° in electrical angle. Here, the electrical angle is one in which one cycle of the sine wave is represented as 360 °. If the number of poles of the rotor is n, the mechanical angle is electrical angle × 2 / n.

  When the motor is rotated, the energization of the coil is sequentially and ideally switched, so that a torque such as T1 indicated by a thick line in FIG. 9A can be obtained, and a high torque can always be obtained. At this time, the timing for switching the energization to the coil is determined by a signal from the detection element. By arranging the two detection elements at an electrical angle of 90 °, the energization can be switched at the most efficient timing.

JP-A-06-0667259 JP-A-2002-359997 However, if there is an error in the mounting position of the detection element, the torque curve is broken as shown by T2 in FIG. 9B, and the efficiency of the motor is reduced. For this reason, a step of adjusting the mounting position of the detection element is required when assembling the motor, which has been a factor of cost increase and quality reduction.

  In the motor disclosed in Patent Document 3 described above, a rotatable rotor having a magnet divided into n portions in the circumferential direction and alternately multipolarly magnetized to different poles, a first coil, and a second coil are provided. A coil, a first yoke having a first magnetic pole that is excited by the first coil and facing the outer peripheral surface of the rotor with a gap, and a first yoke facing the outer peripheral surface of the rotor with a gap therebetween; A second yoke having a second magnetic pole arranged at a phase different from the relative phase between the one yoke and the magnet and being excited by the second coil; and a rotational phase of the magnet at a position facing the outer peripheral surface of the magnet. A first detecting element for detecting the rotational speed of the magnet, selectively detecting an output of the first and second detecting elements, and a first coil and a second coil corresponding to the output result. Switch the direction of energization of the second coil, Drive apparatus is disclosed for rotating without step-out of data.

  In the driving device disclosed in Patent Document 3, the positional accuracy of the first detection element and the second detection element is important, and the performance of the driving device depends on the accuracy at the time of assembly. Therefore, when two or a plurality of detection elements are arranged in one IC package, the package can be accurately positioned and fixed so as to maintain the relationship between the package, the first yoke, and the second yoke and the magnet. The structure is reasonable in terms of simplicity of assembly and suppression of variations in performance. FIG. 10 is an exploded view showing a positional relationship between the magnet, the yoke, and the detecting element in a configuration example, and will be described with reference to FIG.

  However, in the case where an IC in which the first detection element 10a and the second detection element 10b are housed in one package is configured, the IC is diverted and used for a motor or a motor having a different diameter or the number of poles of a rotor. I can't do things.

  This is because the pitch of the detection element of the IC does not match the pitch of the magnetic poles of the magnet, the applied voltage to the coil does not switch as designed, and the intended rotation speed cannot be obtained.

  Further, as the size of the motor is reduced, the distances (t1 and t2) between the first detection element 10a and the second detection element 10b and each of the yokes 6 and 7 must be arranged at short distances. The leakage magnetic flux may affect the first detection element 10a and the second detection element 10b when the excitation is switched, and may further affect the excitation state determination of the yokes 6 and 7.

  Therefore, an object of the present invention is to provide an IC in which an element for detecting the rotation phase of the rotor 3 is housed in one package, and that the IC can be diverted to a motor having a different diameter or the number of poles of the rotor 3. An object of the present invention is to provide a motor which can be used by adjusting the angle at which the IC is assembled.

In order to achieve the above object, a motor according to the present invention
The first magnetized layer and the first magnetized layer, which are divided into n in the circumferential direction and are alternately magnetized at different pitches with different poles at a pitch C, are divided by n in the circumferential direction while being shifted by D with respect to the first magnetized layer. A rotatable rotor having a magnet 2 composed of a second magnetized layer multipolarly magnetized at different pitches with different poles, a first coil, a second coil, and a A first yoke having a first magnetic pole portion that is opposed to the outer peripheral surface of the first magnetized layer with a gap therebetween and that is excited by the first coil;
A second magnetic pole portion which faces the outer peripheral surface of the second magnetized layer of the rotor with a gap, is arranged at a phase different from the relative phase between the first yoke and the magnet, and is excited by the second coil; A second yoke having:
Detecting means for detecting a rotational phase of the magnet and having a first detecting element and a second detecting element arranged at a pitch L, wherein the first detecting element is located at a magnetic pole center position of the magnetized layer. And the second detection element is disposed at a position where the magnetic pole of the magnetized layer is switched. C / 2 = D
It is characterized by comprising.

  ADVANTAGE OF THE INVENTION According to this invention, even if the diameter of a rotor and the number of poles of a rotor magnet differ, the motor which can be assembled with the same detection element and does not generate | occur | produce a step-out can be provided.

  Further, it is possible to provide a motor in which the detection element is not affected by the leakage magnetic flux from the yoke, is switched by the coil application voltage as designed, and the intended rotation speed is obtained.

1 is an external perspective view of a motor according to an embodiment of the present invention. 1 is an exploded perspective view of a motor according to an embodiment of the present invention. It is a sectional view of a motor concerning an embodiment of the present invention. FIG. 4 is a development view illustrating a phase relationship among a magnet, a yoke, and a detection element according to the embodiment of the present invention. FIG. 2 is a cross-sectional view in a direction perpendicular to the axis of the motor, showing a phase relationship among a magnet, a yoke, and a detection element according to the embodiment of the present invention. FIG. 4 is a relationship diagram between a rotation angle of a rotor and a torque of a motor. It shows the torque acting on the rotor when a constant current is passed through the coil of the motor. FIG. 10 is a development view illustrating a phase relationship among a magnet, a yoke, and a detection element according to the second embodiment of the present invention. It shows the torque acting on the rotor when a constant current is passed through the coil of the motor. It is a development view showing a positional relationship of a magnet, a yoke, and a detecting element of a conventional example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  Hereinafter, a motor proposed in the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of a motor proposed in the present invention. FIG. 2 is an assembled perspective view showing the configuration of the stepping motor proposed in the present invention. For the sake of explanation, some parts are shown broken. FIG. 3 is a sectional view of the present embodiment.

  The rotor 3 includes the magnet 2, is formed in a cylindrical shape, divides an outer peripheral surface in a circumferential direction, and is alternately multipolar magnetized to different poles. In the present embodiment, it is magnetized into eight divisions, that is, eight poles. In addition, it may be magnetized not only to 8 poles but also to 4 poles or 12 poles.

A first magnetized layer 2A and a second magnetized layer 2B, which are divided into n equal parts in the circumferential direction and are multipolar magnetized at pitches C alternately at different poles, are formed on the outer cylindrical portion of the magnet 2. Have been. In the present embodiment, the first magnetized layer 2A and the second magnetized layer 2B are configured to be out of phase by 90 degrees in electrical angle. In other words, if the shift amount is D,
C / 2 = D
In a relationship.

  In this embodiment, n = 8, that is, both the first magnetized layer 2A and the second magnetized layer 2B are magnetized to eight poles.

  In this embodiment, since the magnetic poles are magnetized to eight poles, the magnetization angle P is 45 degrees in mechanical angle. In the case of octupole magnetization, the electrical angle of 360 degrees corresponds to two mechanical angles of 90 degrees, so the first magnetized layer 2A and the second magnetized layer 2B are out of phase by 22.5 degrees as the mechanical angle. It is configured.

  The first coil 4 is arranged at one end of the magnet 2 in the axial direction. The first yoke 6 is made of a soft magnetic material, and is formed to face the outer peripheral surface of the magnet 2 with a gap. The first yoke 6 has a plurality of first magnetic pole portions 6a extending from the annular main body portion in the axial direction and arranged at predetermined intervals in the circumferential direction. The first magnetic pole portion 6a is excited by energizing the first coil 4. The magnetic pole portion 6a faces the outer peripheral surface of the first magnetized layer 2A of the magnet 2 with a gap.

  The first inner yoke 8 is made of soft magnetic material, passes through the inner diameter of the first coil 4, and is fixed to the first yoke 6 at an 8a portion. In the first inner yoke 8, the cylindrical magnetic pole portion 8b is opposed to the inner diameter portion of the first magnetized layer 2A of the magnet 2 with a gap, and the cylindrical magnetic pole portion 8b is excited by the first coil 4. The portion of the cylindrical magnetic pole portion opposite to the first magnetic pole portion 6a is excited to a polarity opposite to the polarity of the first magnetic pole portion 6a.

The second coil 5 is disposed at the other end of the magnet 2 opposite to the one end in the axial direction to which the first coil 4 is attached. The second yoke 7 is made of a soft magnetic material, and is formed facing the outer peripheral surface of the magnet 2 with a gap. Further, the second yoke 7 has a plurality of second magnetic pole portions 7a extending in the axial direction from the annular main body portion and arranged at predetermined intervals in the circumferential direction. The second magnetic pole portion 7a is excited by energizing the second coil 5. The second magnetic pole portion 7a faces the outer peripheral surface of the second magnetized layer 2B of the magnet 2 with a gap.
The second inner yoke 9 is made of a soft magnetic material, passes through the inner diameter of the second coil 5, and the inner yoke 9a is fixed to the second yoke 7.

  In the second inner yoke 9, the cylindrical magnetic pole portion 9b is opposed to the inner diameter portion of the second magnetized layer 2B of the magnet 2 with a gap, and the cylindrical magnetic pole portion 9b is excited by the second coil 5. The portion of the cylindrical magnetic pole portion facing the second magnetic pole portion 7a is mainly excited to a polarity opposite to the polarity of the second magnetic pole portion 7a. The rotor 3 integrally formed with the magnet 2, the 8c portion of the first inner yoke 8, and the 9c portion of the second inner yoke 9 are rotatably fitted. The torque applied to the rotor 3 can be changed by switching the poles (N pole, S pole) that are excited by the first magnetic pole 6a and the second magnetic pole 7a.

  The rotor rotation detecting unit 10 is configured by detecting means of a first magnetic sensor (first detecting element) 10a and a second magnetic sensor (second detecting element) 10b, and includes a first magnetic sensor 10a and a second magnetic sensor 10b. Are arranged at an interval L in the same package. Each detecting element is a Hall element for detecting a magnetic flux of the magnet 2, and the rotor rotation detecting unit 10 is positioned and fixed to a side surface of the motor cover 12 by a positioning hole 12 b.

  The motor cover 12 is made of a non-magnetic material, and the first magnetic pole portion 6a and the second magnetic pole portion 7a are disposed on the inner diameter portion 12a so as to be shifted by about 90 degrees in electrical angle with respect to the magnetization phase of the magnet 2. Thus, the first yoke 6 and the second yoke 7 are fitted and fixed at a predetermined relative position.

  In this embodiment, the magnetic pole portion 6a of the first yoke 6 and the magnetic pole portion 7a of the second yoke 7 are fixed in a phase facing each other.

FIG. 4 is a developed view showing a phase relationship among the first yoke 6, the second yoke 7, the first magnetized layer 2A and the second magnetized layer 2B of the magnet 2, and the detection element. explain. The motor cover 12 is arranged such that the first magnetic pole portion 6a of the first yoke 6 and the second magnetic pole portion 7a of the second yoke 7 are shifted by 90 degrees in electrical angle with respect to the magnetization phase of the magnet 2. Thus, the first yoke 6 and the second yoke 7 are fixedly held. Assuming that n is the number of magnetized poles, the electrical angle is α degrees × 2 / n = the mechanical angle β degrees. Therefore, if the magnet 2 of this embodiment has eight poles, the electrical angle is 90 degrees and the mechanical angle is 22.5 degrees. Becomes

  The magnet 2 is composed of a first magnetized layer 2A and a second magnetized layer 2B, and each magnetized layer is divided into n parts in the circumferential direction (n = 8 in the present embodiment) and is alternately multi-pole attached to different poles. Magnetized. Since the first magnetized layer 2A and the second magnetized layer 2B are configured to be out of phase by 90 degrees in electrical angle, as a result, the first magnetic pole portion 6a of the first yoke 6 and the second The second magnetic pole portion 7a of the yoke 7 has a mechanical angle of 0 degrees with respect to the phase facing each other, that is, the first yoke 6, so that the first magnetic pole portion 6a And the second magnetic pole portion 7a are fixed in a phase in which they face each other.

  The first magnetic sensor 10a is arranged at a position facing the outer peripheral surface of the second magnetized layer 2B so as to be able to detect the phase of the second magnetized layer 2B. The second magnetic sensor 10b is arranged at a position facing the outer peripheral surface of the first magnetized layer 2A, and can detect the phase of the first magnetized layer 2A.

  As described above, the first magnetized layer 2A and the second magnetized layer 2B are configured to be out of phase with each other by an electrical angle of 90 degrees, so that the first detecting element 10a has the phase of the second magnetized layer 2B. Is detected, the position where the electrical angle of the first magnetized layer 2A is out of phase by 90 degrees is detected.

  Similarly, the second magnetic sensor 10b detects a position where the phase of the second magnetized layer 2B is shifted by 90 degrees in electrical angle by detecting the phase of the first magnetized layer 2A.

  The structure of the rotor 3, the first coil 4, the second coil 7, the first yoke 6, the second yoke 7, and the like integrally formed with the magnet 2 is disclosed by the present applicant in Japanese Patent Application Laid-Open No. 09-331666. Same as proposed. Therefore, driving as an ordinary stepping motor that does not depend on the output results of the first magnetic sensor 10a and the second magnetic sensor 10b is also possible.

  This motor has a magnetic circuit including a first coil 4, a first yoke 6, a plurality of first magnetic pole portions 6a, a first inner yoke 8, and a first magnetized layer 2A of a magnet 2 facing the magnetic circuit. Constitute the first stator unit.

  A second stator unit is a magnetic circuit including a second coil 5, a second yoke 7, a plurality of second magnetic pole portions 7a, and a second magnetized layer 2B of the magnet 2 facing the second inner yoke 9. Is configured.

  FIG. 5 is a cross-sectional view in the direction perpendicular to the axis of the motor showing the phase relationship between the yoke, the detecting element, and the magnet, and the description will be made with reference to FIG.

The upper section is an AA section, and the lower section is a BB section at that time. The motor cover 12 is omitted. In FIG. 5, the rotor phase is such that the distance between the center Q1 of the magnetized pole of the rotor and the first magnetic pole 6a and the distance between Q1 and the second magnetic pole 7a are the same. This state is referred to as the initial state of the rotor, and the electrical angle is set to 0 °. When the clockwise rotation is performed from FIG. 5A, the second coil 5 is driven when the second magnetic sensor 10b detects the N pole. The second yoke 7 is excited to the S pole. When the second magnetic sensor 10b detects the S pole, the second yoke 6 is excited to the N pole.

  The first coil 4 excites the first yoke 6 to the S pole when the first magnetic sensor 10a detects the S pole, and when the first magnetic sensor 10a detects the N pole. , And the first yoke 6 is excited to the N pole.

  In the state of FIG. 5B, the magnet 2 rotates clockwise regardless of the state of the first coil 4. When the clockwise rotation is performed, the first magnetic sensor 10a detects the S pole and excites the first yoke 6 to the S pole, and rotates to the position shown in FIG. 5C.

  In the state shown in FIG. 5C, the second magnetic sensor 10b excites the second yoke 7 to the N pole in order to detect the S pole, and rotates to the position shown in FIG. 5D.

  When the state shown in FIG. 5D is reached, the first magnetic sensor 10a excites the first yoke 6 to the N pole to detect the N pole, and rotates to the position shown in FIG. 5A.

  After that, it rotates by repeating the same movement.

  Since the first magnetized layer 2A and the second magnetized layer 2B are configured to be out of phase by an electrical angle of 90 degrees as described above, the first magnetic sensor 10a determines the phase of the second magnetized layer 2B. Is detected, the position where the electrical angle of the first magnetized layer 2A is out of phase by 90 degrees is detected. Similarly, the second magnetic sensor 10b detects the position of the second magnetized layer 2B shifted by 90 degrees in electrical angle by detecting the phase of the first magnetized layer 2A.

  When the rotor 3 rotates clockwise, the phase of the rotor whose pole center Q1 of the magnetized first magnetized layer 2A of the rotor 3 is exactly opposite to the center of the first magnetic pole portion 6a (see FIG. 5A 5), (c) shown in FIG. 5), the first magnetic sensor 10a facing the second magnetized layer 2B is arranged so that the boundary between the S pole and the N pole of the magnet 2 can be detected. Have been.

  In other words, the second magnetic sensor 10b determines the angle of deviation (mechanical angle 22.5 degrees) between the first magnetized layer 2A and the second magnetized layer 2B and half the angle of the magnetized angle P (from the center of the magnetized pole to the pole). The first magnetic pole portion 6a is arranged at a position apart from the first magnetic pole portion 6a by a total mechanical angle of 45 degrees (180 degrees in electrical angle) of the angle up to the boundary of 22.5 degrees in mechanical angle.

  The first magnetic pole portions 6a are arranged at every 90 mechanical angles (360 electrical degrees), and the second magnetic pole portions 7a are also arranged at every 90 mechanical angles (360 electrical angles). The first magnetic pole portion 6a and the second magnetic pole portion 7a are arranged to face each other with the same mechanical phase. Therefore, the first magnetic pole portion 6a is located at a position separated from the first magnetic pole portion 6a by a mechanical angle of 45 degrees (180 electrical degrees). 2 The magnetic sensor 10b is arranged at an intermediate position between the first magnetic pole portions 6a and at an intermediate position between the second magnetic pole portions 6b, that is, at a position farthest from the magnetic pole portions. The magnetic pole portions 6a and 7a to be excited are less likely to be affected by the magnetic force. Therefore, the rotation phase of the magnet can be accurately detected.

  Similarly, the first magnetic sensor 10a is arranged as follows. When the rotor 3 rotates clockwise, the center Q2 of the pole of the magnetized second magnetized layer 2B of the rotor 3 is exactly opposite to the center of the second magnetic pole portion 7a (see FIG. 5B 5), the second magnetic sensor 10b facing the first magnetized layer 2A is arranged so as to be able to detect the boundary between the S pole and the N pole of the magnet. I have.

  In other words, the first magnetic sensor 10a determines that the angle of deviation (mechanical angle 22.5 degrees) between the first magnetized layer 2A and the second magnetized layer 2B and half the angle of the magnetized angle P (from the center of the magnetized pole to the pole). The first magnetic pole portion 7a is disposed at a position apart from the first magnetic pole portion 7a by a total mechanical angle of 45 degrees (180 degrees in electrical angle) of the angle up to the boundary of 22.5 degrees in mechanical angle.

  The first magnetic pole portions 6a are arranged at every 90 mechanical angles (360 electrical degrees), and the second magnetic pole portions 7a are also arranged at every 90 mechanical angles (360 electrical angles). The first magnetic pole portion 6a and the second magnetic pole portion 7a are arranged to face each other with the same mechanical phase. Therefore, the first magnetic pole portion 6a is located at a position separated from the first magnetic pole portion 6a by a mechanical angle of 45 degrees (180 electrical degrees). 1 The magnetic sensor 10a is disposed at an intermediate position between the first magnetic pole portions 6a and an intermediate position between the second magnetic pole portions 7a, that is, at a position farthest from the magnetic pole portions. The magnetic pole portions 6a and 7a to be excited are less likely to be affected by the magnetic force. Therefore, the rotation phase of the magnet can be accurately detected.

  Further, the first magnetic sensor 10a and the second magnetic sensor 10b are arranged in parallel with the axial direction of the magnet.

  FIG. 6 is a graph showing the relationship between the rotation angle of the rotor 3 and the motor torque. The horizontal axis represents the electrical angle, and the vertical axis represents the motor torque. The motor torque is positive when the rotor rotates clockwise.

  When a positive current is applied to the first coil 4, the magnetic pole portion 6a of the first yoke 6 is assumed to be magnetized to the N pole. When a current in the positive direction is applied to the second coil 5, the magnetic pole portion 7a of the second yoke 7 is assumed to be magnetized to the N pole.

  During the rotation from FIG. 5D to FIG. 5A, the phase in the state of FIG. 5E is shown as a in FIG. In this state, a force for maintaining the rotational phase is generated, but no rotational driving force is generated. The S pole of the rotor 3 is just attracted to the first yoke 6 and the second yoke 7 and is in a balanced state.

  After this state, when the magnetic pole portion 6a of the second yoke is switched to be excited to the S-pole, the rotor 3 is brought into contact with the center Q1 of the magnetized pole of the first magnetized layer 2A of the rotor 3 and the first pole. Until the distance between the magnetic pole 6a and the distance between the center Q2 of the magnetized pole of the second magnetized layer 2B and the second magnetic pole 7a becomes the same, the phase of the rotor shown in FIG. Rotate.

  In this state, as in the rotor phase shown in FIG. 5E, a force for maintaining the rotational phase is generated, but no rotational driving force is generated. The S pole of the first magnetized layer 2A of the rotor 3 is attracted to the magnetic pole 3a of the first yoke 6, and the N pole of the second magnetized layer 2B of the rotor 3 is the magnetic pole 7a of the second yoke 7. It is attracted to and balanced.

  Thereafter, similarly, the energizing directions of the first coil 4 and the second coil 5 are similarly switched to sequentially change the polarity of the magnetic pole portion 6a of the first yoke 6 and the magnetic pole portion 7a of the second yoke 7, and the rotor 3 Can be rotated. Switching at such timing is referred to as energization switching at an electrical advance angle of 0 degrees. Switching at a timing earlier than this is defined as performing energization switching at the advance angle γ degrees.

  FIG. 7 is a diagram in which the horizontal axis represents the rotation angle of the rotor 3 and the vertical axis represents the torque generated by the energized state of the first coil 4 and the second coil 5. The horizontal axis is represented by an electrical angle.

L1 is a positive current supply to the first coil 4 and a positive power supply to the second coil 5 L2 is a positive power supply to the first coil 4 and a reverse power supply to the second coil 5 L3 is a first power supply to the second coil 5 L4 is the torque generated when the power to the first coil 4 is reverse and the power to the second coil 5 is positive. Show

  However, when the energization of the coil is switched at such a timing, the driving torque is extremely small in the phase immediately before the energization is switched. Therefore, the relationship between the rotational phase and the torque is shown by the hatched portion and the bold line in FIG. As shown in the figure, the output of the motor does not increase.

  Therefore, it is necessary to switch the energization before the magnetic pole portion 7a of the second yoke 7 generates a driving force in the left rotation direction on the N pole of the rotor 3 before the state shown in FIG.

  The drive torque generated when the energization is switched in the phase of FIG. 5A is maximized as shown in FIG. 7B. The energization switching at this timing is energization switching at an electric advance angle of 45 degrees.

  In the case of the right rotation drive, the first magnetic sensor 10a is disposed at a position of 45 degrees of the electric advance angle with respect to the first stator unit, and the second magnetic sensor 10b is arranged with the electric advance of 45 degrees with respect to the second stator unit. Place in position.

  The first magnetic sensor 10a detects the rotation phase of the rotor 3 and switches the energization of the first coil 4, and the second magnetic sensor 10b detects the rotation phase of the rotor 3 and switches the energization of the second coil 5. Therefore, before the state shown in FIG. 5A is reached, the energization is switched at the rotor phase, so that a large rotational driving force can be generated.

  Further, when the switching timing is further advanced, and the electrical advance is 90 degrees at which the energization of the coil is switched in the state shown in FIG. 5 (e), it becomes as shown by the hatched portion in FIG. 7 (c). Similar results are obtained, and a large rotational driving force cannot be obtained. Similarly, in the case of the reverse rotation, when the driving force is generated in the counterclockwise direction from the state of FIG. 5E, the first magnetic sensor 10a moves the electrical angle of the first stator unit by 45 degrees with respect to the first stator unit. That is, the second magnetic sensor 10b is disposed at a position at an electric advance angle of 45 degrees with respect to the second stator unit.

  The rotation phase of the rotor 3 is detected by the first magnetic sensor 10a, and the energization of the first coil 4 is switched. The rotation phase of the rotor 3 is detected by the second magnetic sensor 10b, and the energization of the second coil 5 is energized. If the switching is performed, the energization is switched at the rotor phase before the state shown in FIG. 5D, so that a large rotational driving force can be generated.

  The first magnetic sensor 10a that outputs a signal for switching the excitation state of the first coil 4 is located between the magnetic pole portions 7a of the second yoke 7, and at the timing of switching the energization of the first coil 4, Since the energization of the second coil 5 is not switched, the second coil 5 is not easily affected by a change in the magnetic field due to the energization and does not malfunction. Similarly, the second magnetic sensor 10b that outputs a signal for switching the excitation state of the second coil 5 is located between the magnetic pole portions 6a of the first yoke 6, and the timing for switching the energization of the second coil 5 In this case, since the energization of the first coil 4 is not switched, the first coil 4 is not easily affected by a change in the magnetic field due to the energization and does not malfunction.

  Further, since the first magnetic sensor 10a and the second magnetic sensor 10b are arranged in parallel to the axial direction of the magnet 2, an IC containing the first magnetic sensor 10a and the second magnetic sensor 10b in one package is used. In such a case, the IC can be used for a motor or a motor having a different diameter or the number of poles of a rotor.

  Hereinafter, a motor control device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 8 is a developed view showing a positional relationship between the magnet 2, the yokes 6, 7 and the detecting elements 10a, 10b according to the second embodiment of the present invention.

  In the second embodiment, the cylindrical portion on the outer circumference of the magnet 2 is divided into n equal parts in the circumferential direction and is multipolar magnetized at pitches C alternately at different poles. In the present embodiment, it is magnetized into eight divisions, that is, eight poles. The number of poles is not limited to eight, but may be four or twelve.

  A cylindrical portion on the outer periphery of the magnet 2 is formed with a first magnetized layer 2A and a second magnetized layer 2B that are divided into n in the circumferential direction and are magnetized at pitches C alternately at different poles. .

  In the present embodiment, the first magnetized layer 2A and the second magnetized layer 2B are configured so as to be deviated by an electrical angle of 43.4 degrees (mechanical angle 10.85 °). The shift amount of the second magnetized layer 2B with respect to the first magnetized layer 2A is D. The pitch between the first magnetic sensor (10a) and the second magnetic sensor (10b) is set to L. The angle between the straight line connecting the first magnetic sensor (10a) and the second magnetic sensor (10b) and the circumferential direction of the first magnetized layer (2A) or the second magnetized layer (2B) of the rotor 3 is defined. Assuming α, the relational expression (C / 2−D) = L × cos α according to claim 2 is formed.

  For example, the magnetized pitch amount A of the first magnetized layer 2A of the magnet 2 is 22.5 degrees, and the shift amount D from the opposing second magnetized layer 2B is 10.85 degrees. In the case where the pitch L of the magnetic sensors 10a and 10b is 0.8 mm, the arrangement α of the magnetic sensor 10 is 60 degrees from the expression (C / 2-D) = L × cos α in claim 2.

  Similarly to the first embodiment, when an IC in which the first magnetic sensor 10a and the second magnetic sensor 10b are housed in one package is configured, the IC can be used for a motor or a motor having a different diameter or the number of poles of a rotor. Can be diverted and used.

  The first magnetic sensor 10a located at a mechanical angle of 45 degrees (180 degrees in electrical angle) and separated from the second magnetic pole portion 7a is located at an intermediate position between the second magnetic pole portions 7a, that is, the most from the magnetic pole portions. Since it is arranged at a distant position, it is less likely to be affected by the magnetic force of the magnetic pole portion 6a which is excited by energizing the coil. Therefore, the rotational phase of the magnet 2 can be accurately detected.

  The second magnetic sensor 10b located at a mechanical angle of 45 degrees (180 electrical degrees) away from the first magnetic pole portion 6a is located at an intermediate position between the first magnetic pole portions 6a, that is, the most distant from those magnetic pole portions. And is less likely to be affected by the magnetic force of the magnetic pole portion 6a that is excited by energizing the coil. Therefore, the rotation phase of the magnet can be accurately detected.

  In the second embodiment, even if the shift amount D between the first magnetized layer 2A and the second magnetized layer is not an electrical angle of 90 °, they are arranged according to the relational expression shown in claim 2 to achieve a difference between the first magnetized layer 2A and the second magnetized layer. Similar effects can be obtained.

  As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

1 motor, 2 magnets, 2A first magnetized layer, 2B second magnetized layer,
3 rotor, 4 first coil, 5 second coil, 6 first yoke,
6a first magnetic pole portion, 7 second yoke, 7a second magnetic pole portion,
10 rotor rotation detecting section, 10a first detecting element, 10b second detecting element,
12 Motor cover, 12a Fitting part, 12b Positioning hole

Claims (3)

The first magnetized layer and the first magnetized layer, which are divided into n in the circumferential direction and are alternately magnetized at different pitches with different poles at a pitch C, are divided by n in the circumferential direction while being shifted by D with respect to the first magnetized layer. A rotatable rotor having a magnet 2 composed of a second magnetized layer multipolarly magnetized at different pitches alternately at a pitch A, a first coil, a second coil, and a A first yoke having a first magnetic pole portion that is opposed to the outer peripheral surface of the first magnetized layer with a gap therebetween and that is excited by the first coil;
A second magnetic pole portion that faces the outer peripheral surface of the second magnetized layer of the rotor with a gap, is arranged at a phase different from the relative phase between the first yoke and the magnet, and is excited by the second coil; A second yoke having:
Detecting means for detecting a rotational phase of the magnet and having a first detecting element and a second detecting element arranged at a pitch L, wherein the first detecting element is located at a magnetic pole center position of the magnetized layer. The motor, wherein the second detection element is disposed at a position where a magnetic pole of the magnetized layer is switched, and C / 2 = D. Assuming that an angle between a straight line connecting the first detection element and the second detection element and a circumferential direction of the first magnetized layer or the second magnetized layer of the rotor is α, (C / 2− D) = L × cos α
The motor according to claim 1, wherein the motor is configured to be as follows. A first detection unit that switches energization of the first coil according to the output state, and a second detection unit that switches energization of the second coil according to the output state,
2. The device according to claim 1, wherein the first detecting means is arranged at a position facing the second magnetized layer, and the second detecting means is arranged at a position facing the first magnetized layer. Motor as described.