JP2009095172A - Motor and apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact motor capable of adjusting a sensor with high accuracy in detecting the rotation (position) of the motor. <P>SOLUTION: The motor 1 includes: a motor unit including a rotor 3 equipped with a magnet 2 having a polarized surface which is multi-polarized, magnetic pole portions 4, 5 facing the polarized surface of the magnet and coils 6, 7 for energizing the magnetic pole portions; the sensor 8 for outputting a signal according to the rotation of the motor; a sensor holder 9 for holding the sensor; terminal portions 9-2, 9-3 for feeding the coils; and a wiring board 10 connected to the sensor and the terminal portions. The sensor holder is attached to the motor unit with structures 9-4, 11 allowing the sensor holder to adjust a position in a rotational direction of the rotor relative to the magnetic pole portions when the motor is assembled. The terminal portions are mounted so as to move to the motor unit together with the sensor holder whose position is adjusted in such a state that the sensor is held by the sensor holder and the wiring board is connected to the sensor and terminal portions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor including a sensor such as a magnetic sensor that outputs a signal corresponding to the rotation of a rotor.

  Stepping motors are small in size, have high torque and long life, and can easily perform digital positioning operations with open loop control, so they can be used in various devices such as cameras, optical disk devices, printers, and projectors. Widely used.

  However, the stepping motor has a problem that step-out easily occurs when the motor rotates at high speed or when the load on the motor is large. There is also a problem that the efficiency is lower than that of a brushless motor or a DC motor.

  By attaching an encoder as a position sensor to the stepping motor and switching the energization direction according to the position of the rotor, the operation of a so-called brushless DC motor can be performed to prevent step-out. For this purpose, it is necessary to attach an encoder such as a magnetic sensor with high accuracy to the brushless DC motor. Hereinafter, the mounting accuracy to the brushless DC motor when a magnetic sensor is used as the encoder will be described.

  The upper graph in FIG. 4 shows the torque acting on the rotor when a constant current is passed through the two-phase coil of the brushless DC motor. Since currents in the forward direction and the reverse direction can flow through each of the two coils, four types of torque distributions A−B−, A + B−, A + B +, and A−B + are generated as shown in the figure. . These are sinusoidal torque waveforms having the same shape, and have a phase difference of 90 ° in electrical angle.

  The electrical angle represents one cycle of a sine wave as 360 °. When the number of poles of the rotor is n, the electrical angle of 1 ° corresponds to (2 × actual angle / n).

  In order to rotate the motor, by sequentially switching energization to the two coils, a torque waveform indicated by T1 in FIG. 4 is obtained, so that a high torque is always obtained. At this time, the timing for switching the energization to the coil is determined by the two-phase signals S1 and S2 from the magnetic sensor.

  The magnetic sensor is arranged so that output signals S1 and S2 from the magnetic sensor as shown in the lower graph of FIG. 4 can be obtained, and the energization direction to the coil according to the signs of the output signals S1 and S2 from the magnetic sensor By switching between, the maximum motor output can be obtained.

  However, if there is an error in the mounting position of the magnetic sensor, the torque waveform T2 shown in FIG. 4 is lost, and the efficiency of the motor is reduced or noise is generated. For this reason, it is necessary to adjust the mounting position of the magnetic sensor.

  In the motor disclosed in Patent Document 1, an elongated hole is provided in a substrate to which a position sensor is attached, and a position sensor attachment position can be adjusted by using a screw passing through the elongated hole.

In Patent Document 2, the position sensor is attached to a connecting ring that connects the yokes to reduce the size of the motor with the position sensor.
JP-A-9-182403 JP-A-10-243624

  However, in the method disclosed in Patent Document 1, since there is a limit to downsizing the screw and the substrate, this cannot be used when the motor is further downsized.

  Further, in the motor disclosed in Patent Document 2, the position sensor is integrally fixed to a coil terminal portion provided in the motor body via a power feeding cable. Therefore, the position where the position sensor is attached cannot be adjusted.

  In the motor of Patent Document 2, by providing an adjustment allowance when fixing the power supply cable, the position sensor, and the coil terminal portion, it is possible to adjust the mounting position of the position sensor. However, in this case, the positional relationship between the coil terminal portion and the position sensor is not determined, and it is necessary to increase the size of the power supply cable by the amount of adjustment.

  As the motor is reduced in size, the relative dimensions of the coil terminal portion and the power feeding cable with respect to the motor body increase. Therefore, an increase in the size of the power supply cable directly leads to an increase in the size of the motor. Further, in the motor disclosed in Patent Document 2, it is difficult to adjust the position of the position sensor while energizing the coil, and as a result, the sensor position cannot be adjusted with sufficiently high accuracy.

  The present invention provides a motor capable of high-precision adjustment of a sensor related to rotation detection (or position detection) of the motor, and a device including the motor, and a method for manufacturing the motor, while being small in size. .

  A motor according to one aspect of the present invention is a motor unit including a rotor including a magnet having a magnetized surface magnetized with multiple poles, a magnetic pole portion facing the magnetized surface of the magnet, and a coil for exciting the magnetic pole portion. And a sensor that outputs a signal corresponding to the rotation of the rotor, a sensor holder that holds the sensor, a terminal part for supplying power to the coil, and a wiring board connected to the sensor and the terminal part. The sensor holder is assembled to the motor unit by a structure that allows position adjustment in the rotation direction of the rotor with respect to the magnetic pole portion of the sensor holder when the motor is assembled. The terminal portion is provided to move relative to the motor unit together with the sensor holder whose position is adjusted in a state where the sensor is held by the sensor holder and the wiring board is connected to the sensor and the terminal portion. It is characterized by.

  In addition, the apparatus which drives a to-be-driven member with the said motor comprises the other side surface of this invention.

  According to another aspect of the present invention, there is provided a motor manufacturing method comprising: a rotor including a magnet having a magnetized surface that is magnetized in multiple poles; a magnetic pole portion that faces the magnetized surface of the magnet; A motor unit including a coil to be rotated, a sensor that outputs a signal corresponding to the rotation of the rotor, a sensor holder that holds the sensor, a terminal unit that supplies power to the coil, and the sensor and the terminal unit The present invention is applied to a motor having a wiring board. The manufacturing method includes assembling the sensor holder to a motor unit so that the position of the sensor holder relative to the magnetic pole portion in the rotational direction of the rotor can be adjusted, the sensor being held by the sensor holder, and the wiring board being And adjusting the position of the sensor holder while being connected to the sensor and the terminal portion. And in this position adjustment step, a terminal part is moved with respect to a motor unit with a sensor holder, It is characterized by the above-mentioned.

  According to the present invention, it is possible to adjust the position of the sensor holder (that is, the sensor) with respect to the magnetic pole portion even when the wiring board is connected to the sensor and the terminal portion. Therefore, it is not necessary to provide a long hole in the wiring board, and the wiring board can be downsized, that is, the motor can be downsized. Moreover, since the position of the sensor holder can be adjusted while supplying power to the coil, more accurate position adjustment can be performed.

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

  FIG. 1 shows an exploded view of a motor that is Embodiment 1 of the present invention.

  The motor 1 includes a rotor 3 having a magnet 2, first and second yokes 4 and 5, first and second coils 6 and 7, a magnetic sensor 8, a sensor holder 9, and a wiring board. And a power supply cable 10. Furthermore, the motor 1 also has a yoke fixing cover 11 and first and second bearings 12 and 13.

  The magnet 2 is formed in a cylindrical shape, and its outer peripheral surface (magnetized surface) is divided into n parts (n = 10 in this embodiment), and is multipole magnetized so that S poles and N poles are alternately formed. ing. A rotor unit is configured by fixing the magnet 2 to the rotor 3.

  The first and second yokes 4 and 5 are made of a soft magnetic material. The first yoke 4 has n / 2 first magnetic pole portions 4-1 facing the magnetized surface of the magnet 2 at equal intervals in the circumferential direction. In the present embodiment, five first magnetic pole portions 4-1 are provided, and the distance between them is 360 / n ° (72 degrees in the present embodiment). Each of the first magnetic pole portions 4-1 extends in parallel to the rotation axis of the rotor unit (hereinafter referred to as the rotor rotation axis). The first magnetic pole part 4-1 is excited by energizing the first coil 6.

  The second yoke 5 has n / 2 second magnetic pole portions 5-1 facing the magnetized surface of the magnet 2 at equal intervals in the circumferential direction. In the present embodiment, five second magnetic pole portions 5-1 are provided, and the distance between them is 360 / n ° (72 degrees in the present embodiment). Each of the second magnetic pole portions 5-1 extends in parallel to the rotor rotation axis. The second magnetic pole part 5-1 is excited by energizing the second coil 7.

  The first and second magnetic pole parts 4-1, 5-1 are arranged so as to have a predetermined phase difference. The predetermined phase difference is about 90 / n ° (18 ° in this embodiment). However, it may be shifted from this value by several degrees in order to reduce the cogging torque.

  The first and second coils 6 and 7 are each formed by winding a conducting wire around bobbins 6-1 and 7-1. The number of windings is substantially the same between the first coil 6 and the second coil 7, and the resistance value is also substantially the same. The 1st and 2nd coils 6 and 7 are arrange | positioned so that the center may be located coaxially with a rotor rotating shaft.

  The yoke fixing cover 11 is made of a nonmagnetic material, and has a yoke fixing groove 11-1 for fixing and holding the first yoke 4 and the second yoke 5 with a predetermined phase difference. ing. The yoke fixing cover 11 has an opening 11-2 for avoiding interference with a magnetic sensor 8 described later.

  The first bearing 12 and the second bearing 13 are respectively fixed to the first yoke 4 and the second yoke 5 and rotatably support the rotor unit.

  The motor unit is constituted by the yoke fixing cover 11, the rotor units (2, 3), the first and second yokes 4, 5, the first and second coils 6, 7, and the first and second bearings 12, 13. Is done. On the other hand, the magnetic sensor 8 and the sensor holder 9 constitute a sensor unit.

  The magnetic sensor 8 is a sensor that outputs a signal corresponding to a change in a magnetic field such as a Hall element or an MR element. The magnetic sensor 8 is disposed so as to be close to the magnetized surface of the magnet 2. When the rotor unit rotates and the magnetized surface of the magnet 2 moves (rotates) with respect to the magnetic sensor 8, the magnetic field sensed by the magnetic sensor 8 changes. Therefore, the magnetic sensor 8 changes the magnetic field, that is, the rotor. A signal (voltage) corresponding to the rotation of the unit is output.

  In the chip of the magnetic sensor 8, as shown in FIG. 3, two sensitive magnetic poles 8a and 8b having a phase difference of 90 degrees are provided. The rotational position of the rotor unit can be obtained by reading the two-phase output signals (S1 and S2 shown in FIG. 4) from the two magnetic poles 8a and 8b by a driver circuit (or control circuit) (not shown). .

  The sensor holder 9 is made of an insulating material, and a hole 9-1 for holding the magnetic sensor 8 is formed on the upper surface in FIG. The sensor holder 9 is provided with four (two pairs) coil terminal portions 9-2 and 9-3. Furthermore, the sensor holder 9 has a cylindrical opening 9-4 that opens in the axial direction of the rotor unit.

  A yoke fixing cover 11 whose outer peripheral surface has a cylindrical shape is lightly press-fitted into the inner periphery of the cylindrical opening 9-4. With such a structure (assembled structure), the sensor holder 9 can be rotated with respect to the yoke fixing cover 11 in the rotation direction of the rotor unit.

  In other words, the sensor holder 9 has a structure that enables position adjustment in the rotational direction of the rotor unit with respect to the first and second magnetic pole portions 4-1 and 5-1 of the sensor holder 9 when the motor 1 is assembled. Installed in the motor unit.

  The power supply cable 10 is formed based on a flexible sheet. On the sheet, a wiring pattern for supplying power to the coil terminal portions (terminal portions) 9-2 and 9-3, a wiring pattern for supplying power to the magnetic sensor 8, and a signal from the magnetic sensor 8 as a driver circuit. A wiring pattern to be input to is provided. However, these wiring patterns are omitted in the figure.

  The first bearing 12 and the second bearing 13 are respectively fixed to the first yoke 4 and the second yoke 5 and rotatably support the rotor unit.

  A method for manufacturing the motor with a sensor configured as described above (an assembly method and a position adjustment method for the sensor (sensor holder)) will be described with reference to a flowchart shown in FIG.

  First, in step S <b> 101, the first coil 6 and the first bearing 12 are fixed to the first yoke 4. Further, the second coil 7 and the second bearing 13 are fixed to the second yoke 5.

  In step S <b> 102, the first yoke 4 and the second yoke 5 are fixed to the fixing groove 11-1 of the yoke positioning cover 11. Accordingly, the first and second yokes 4 and 5 are arranged so as to have an appropriate positional (phase difference) relationship. At this time, the rotor 3 is rotatably supported by the first and second bearings 12 and 13.

  Next, in step S <b> 103, the sensor holder 9 is temporarily assembled to the yoke positioning cover 11. In this state, the sensor holder 9 can be rotated with respect to the yoke positioning cover 11 and can be adjusted (rotated) with respect to the first and second magnetic pole portions 4-1 and 5-1.

  Thereafter, both ends of the first coil 6 are connected to the pair of coil terminal portions 9-2, and both ends of the second coil 7 are connected to the pair of coil terminal portions 9-3. At this time, The sensor holder 9 is loosened to the extent that it can rotate with respect to the yoke positioning cover 11.

  Next, in step S <b> 104, the power feeding cable 10 in which the magnetic sensor 8 is mounted (that is, connected to the magnetic sensor 8) is attached to the sensor holder 9. At this time, the magnetic sensor 8 is inserted into a hole 9-1 formed in the sensor holder 9 and fixed (held). Further, the feeding cable 10 is electrically connected to the coil terminal portions 9-2 and 9-3 to which both ends of the first coil 6 and the second coil 7 are connected. At this time, the coil terminal portions 9-2 and 9-3 are positioned with respect to the sensor holder 9 by being inserted into holes formed in the power feeding cable 10. The power supply cable 10 is connected to a driver circuit (not shown), and enables excitation of the first and second yokes 4 and 5.

  In step S105, the sensor holder 9, that is, the position of the sensor 8 with respect to the first and second magnetic pole portions 4-1, 5-1 is adjusted. That is, the position of the sensor holder 9 is adjusted in a state where the magnetic sensor 8 is held by the sensor holder 9 and the feeding cable 10 is connected to the magnetic sensor 8 and the coil terminal portions 9-2 and 9-3.

  The coil terminal portions 9-2 and 9-3 are provided in the sensor holder 9 as described above. Therefore, as shown in FIG. 2, when the sensor holder 9 is rotated with respect to the yoke positioning cover 11, the coil terminal portions 9-2 and 9-3 also move (rotate) with respect to the motor unit together with the sensor holder 9. To do. Therefore, at the time of this position adjustment, the first and second coils 6 and 7 can be energized to excite the first and second yokes 4 and 5. That is, torque can be generated in the rotor unit.

  By switching the energization direction to the first and second coils 6 and 7 and measuring the torque at that time, four types of torque curves (A−B−, A + B−, A + B +, A−B +) shown in FIG. ) Is obtained. Then, the position of the magnetic sensor 8 is adjusted so that the positive and negative of the output signals S1, S2 from the magnetic sensor 8 (magnetic poles 8a, 8b) are switched at the intersection of these torque curves. By such position adjustment, the output obtained from the motor can be brought close to the maximum.

  When the sensor position adjustment is completed, in step S106, the sensor holder 9 is fixed to the yoke positioning cover 11 by a method such as adhesion or welding.

  According to the present embodiment, since the coil terminal portions 9-2 and 9-3 move with respect to the motor unit together with the sensor holder 9 in the sensor position adjustment, the feeding cable 10 is moved to the coil terminal portions 9-2 and 9-3. It is possible to adjust the position of the sensor holder 9 while being connected. Therefore, the position of the magnetic sensor 8 can be adjusted appropriately (with high accuracy) while referring to the torque that is actually generated, and as a result, the performance of the motor can be fully exhibited.

  Further, according to the present embodiment, the number of parts does not increase for sensor position adjustment, and parts that hinder downsizing of the entire motor are not used. For this reason, a small motor with a sensor can be realized.

  Furthermore, in this embodiment, the positional relationship between the coil terminal portions 9-2 and 9-3 and the magnetic sensor 8 is fixed. For this reason, it is not necessary to provide an adjustment (margin) in the power supply cable 10, and the power supply cable 10 is not increased in size. Therefore, it is effective for further miniaturization of the entire motor.

  FIG. 5 shows an exploded view of a motor that is Embodiment 2 of the present invention. In the present embodiment, components common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  In the motor 101 of this embodiment, the coil terminal portions 106-2 and 107-2 are connected to the first bobbin 106-1 and the second bobbin 107-1 by connecting members 106-3 and 107- as flexible members. 3 is attached. For this reason, the coil terminal portions 106-2 and 107-2 are connected to the coils 106 and 107, that is, to the motor units (2 to 6, 11 to 13) by the deformation of the connecting members 106-3 and 107-3. Can move.

  Similarly to the first embodiment, the sensor holder 109 has a hole 109-1 for holding the magnetic sensor 8 and a cylindrical opening 109-4 into which the yoke positioning cover 11 is lightly press-fitted. Also in this embodiment, the position of the sensor holder 109 in the rotational direction of the rotor unit with respect to the first and second magnetic pole portions (first and second yokes 4 and 5) of the sensor holder 109 during assembly of the motor 101 is adjusted. It is assembled to the motor unit by a structure that enables

  Further, the sensor holder 109 is formed with a recess (engagement portion) 109-5 having a shape that can be engaged with the coil terminal portions 106-2 and 107-2 in the rotation direction of the rotor unit. When the sensor holder 109 is assembled to the motor unit, the coil terminal portions 106-2 and 107-2 are disposed in the recess 109-5.

  Similar to the first embodiment, in this embodiment, the magnetic sensor 8 is held by the sensor holder 109 and the power supply cable 10 is connected to the magnetic sensor 8 and the coil terminal portions 106-2 and 107-2. The position of the holder 109 is adjusted with respect to the first and second magnetic pole portions. Specifically, the sensor holder 109 is rotated with respect to the yoke positioning cover. Accordingly, as shown in FIG. 6, the coil terminal portions 106-2 and 107-2 engaged with the recess 109-5 are moved together with the sensor holder 109 by deformation of the connecting members 106-3 (not shown) and 107-3. Move relative to the motor unit.

  Therefore, also in the present embodiment, as in the first embodiment, the position of the sensor holder 109 can be adjusted while the feeding cable 10 is connected to the coil terminal portions 106-2 and 107-2. Therefore, the position of the magnetic sensor 8 can be adjusted appropriately (with high accuracy) while referring to the actually generated torque.

  Also in this embodiment, the positional relationship between the coil terminal portions 106-2 and 107-2 and the magnetic sensor 8 is fixed. For this reason, it is not necessary to provide an adjustment (margin) in the power supply cable 10, and the power supply cable 10 is not increased in size. Therefore, it is effective for downsizing the entire motor.

  In Example 1, it is necessary to wind the end of the coil around the coil terminal after the motor is assembled. In this example, when the coil is wound around the bobbin, the end of the coil can be wound around the coil terminal. it can. This is effective for improving the efficiency of assembly.

  In each of the above-described embodiments, the case where a magnetic sensor is used as the sensor has been described. However, a sensor other than the magnetic sensor may be used as long as it can obtain information on the position of the motor. For example, a position sensor that combines a pulse plate and an optical sensor may be used.

  Even in configurations other than the above-described embodiments, the sensor is held by the sensor holder, and the wiring board is connected to the sensor and the terminal portion, and moves with respect to the motor unit together with the sensor holder whose position is adjusted. If it is provided, it is included in the present invention.

  FIG. 8 shows a digital camera as an apparatus including the motor 1 (101) described in the first embodiment (or the second embodiment).

  The camera 112 includes a zoom lens barrel (hereinafter referred to as a lens barrel) 100 that can change the imaging magnification. The motor 1 is used as a zoom drive source or a focus drive source of the lens barrel 100 as a driven member.

  In front of the camera 112, a finder 117 that determines the composition of the subject, a light emitting unit 116 that emits auxiliary light when performing photometry / ranging, a flash 118 that illuminates the subject, and the lens barrel 100 are provided. .

  On the top surface of the camera 112, a release button 113, a power ON / OFF button 115, and a zoom switch 114 are provided. For example, when the power ON / OFF button 115 is turned on or when the zoom switch 114 is operated, the motor 1 operates through the driver circuit that receives a signal from a camera microcomputer (not shown). Thereby, the protrusion drive and zoom drive from the retracted state of the lens barrel 100 are performed.

  The motors 1 and 101 described in the first and second embodiments can be widely used as a drive source for driven members in various devices such as an optical disk device, a printer, and a projector, as well as the above-described cameras.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

1 is an exploded perspective view of a motor that is Embodiment 1 of the present invention. FIG. 3 is a diagram illustrating a state of sensor position adjustment in the motor according to the first embodiment. Schematic which shows the magnetic sensor provided in the motor of Example 1,2. The graph which shows the relationship between a motor torque and a magnetic sensor signal. The exploded perspective view of the motor which is Example 2 of the present invention. FIG. 6 is a diagram illustrating a state of sensor position adjustment in the motor according to the second embodiment. 6 is a flowchart illustrating a method for manufacturing the motor according to the first and second embodiments. FIG. 3 is a perspective view of a camera including the motors of Examples 1 and 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Motor 2 Magnet 3 Rotor 4, 5 Yoke 6, 7, 106, 107 Coil 8 Magnetic sensor 9, 109 Sensor holder 9-2, 9-3, 106-2, 107-2 Coil terminal part 10 Feeding cable 11 Yoke fixed cover 12, 13 Bearing 106-3, 107-3 Connecting member

Claims (5)

A motor unit including a rotor including a magnet having a magnetized surface magnetized with multiple poles, a magnetic pole portion facing the magnetized surface of the magnet, and a coil for exciting the magnetic pole portion;
A sensor that outputs a signal corresponding to the rotation of the rotor;
A sensor holder for holding the sensor;
A terminal portion for supplying power to the coil;
A motor having the sensor and a wiring board connected to the terminal portion,
The sensor holder is assembled to the motor unit by a structure that enables position adjustment in the rotation direction of the rotor with respect to the magnetic pole portion of the sensor holder when the motor is assembled.
The terminal portion moves relative to the motor unit together with the sensor holder whose position is adjusted in a state where the sensor is held by the sensor holder and the wiring board is connected to the sensor and the terminal portion. The motor is provided as described above.   The motor according to claim 1, wherein the terminal portion is provided on the sensor holder. The terminal portion is attached to the coil via a flexible member,
The motor according to claim 1, wherein the sensor holder has a shape that can be engaged with the terminal portion in a rotation direction of the rotor. A motor according to any one of claims 1 to 3,
And a driven member driven by the motor. A motor unit including a rotor including a magnet having a magnetized surface magnetized with multiple poles, a magnetic pole portion facing the magnetized surface of the magnet, and a coil for exciting the magnetic pole portion;
A sensor that outputs a signal corresponding to the rotation of the rotor;
A sensor holder for holding the sensor;
A terminal portion for supplying power to the coil;
A method of manufacturing a motor having the sensor and a wiring board connected to the terminal portion,
Assembling the sensor holder to the motor unit such that the position of the sensor holder relative to the magnetic pole portion in the rotational direction of the rotor can be adjusted;
Adjusting the position of the sensor holder in a state where the sensor is held by the sensor holder and the wiring board is connected to the sensor and the terminal portion,
In the position adjusting step, the terminal part is moved with respect to the motor unit together with the sensor holder.