JP4541939B2 - Electromagnetic actuator and drive device including the same - Google Patents

Description

  The present invention relates to an outer rotor type electromagnetic actuator and a drive device including the same.

As a stepping motor that is a conventional outer rotor type electromagnetic actuator, for example, as shown in Patent Document 1, a rotor made of a cylindrical permanent magnet, a plurality of coil bobbins arranged in an axial direction of a rotating shaft, and a rotor And a plurality of stators arranged on the upper and lower sides of each coil bobbin. Each stator is formed in a disk shape having a large number of comb teeth.
Japanese Patent Laid-Open No. 11-225466

  The stepping motor of Patent Document 1 described above has a problem that it has two stators per one coil bobbin and becomes larger in the axial direction. In addition, since the shape of the stator is comb-like and the bending process is necessary and complicated, and since a large number of stators are separately provided, variation in component accuracy between each stator and incorporation accuracy are reduced. Variations are likely to occur, and as a result, the rotational stop position accuracy of the rotor is reduced, causing torque irregularities and quality variations among the stepping motors.

  The present invention has been made in view of the above circumstances, and is an electromagnetic actuator that is miniaturized, improves rotor stop position accuracy, reduces torque unevenness, and reduces quality variations among products. An object of the present invention is to provide a sector opening / closing device provided with

In order to achieve the above object, the electromagnetic actuator of the present invention comprises:
A stator composed of a support shaft and a plurality of rod-shaped members formed integrally with the support shaft and spaced apart in the axial direction of the support shaft so as to form a fixed angle with respect to the support shaft. When,
A coil that is wound directly between the plurality of rod-shaped members on the support shaft and magnetized by exciting the end of the rod-shaped member ;
A plurality of magnetic poles in the circumferential direction is formed in a cylindrical shape, said plurality of magnetic poles and the stator so that the ends of the plurality of bar-like members are opposed are arranged therein, positive about said support shaft A rotor that can rotate in both directions is provided.

  Further, the support shaft constitutes a magnetic circuit together with the plurality of rod-shaped members.

Further, the plurality of rod-shaped members are three rod-shaped members, and the three rod-shaped members are arranged so as to form an angle of 60 degrees around the support shaft,
The rotor may have four magnetic poles having different polarities alternately in the circumferential direction.

  In order to achieve the above object, a drive device of the present invention includes the above-described electromagnetic actuator, and a yoke for preventing magnetic flux leakage is integrally provided on the outer periphery of the rotor, and the driving force of the rotor is provided on the outer periphery of the yoke. A transmission unit for transmission is provided.

  According to the present invention, an electromagnetic actuator that is downsized with a simple configuration, improves the stop position accuracy of the rotor, reduces torque unevenness, and reduces variations in quality among products, and a drive including the same An apparatus can be provided.

  An electromagnetic actuator according to an embodiment of the present invention will be described below with reference to the drawings. The electromagnetic actuator 10 is a permanent magnet type (PM (Permanent Magnet) type) outer rotor type stepping motor, and rotates the drive target attached to the rotor when the rotor rotates.

  As shown in FIGS. 1 to 3, the electromagnetic actuator 10 includes a stator 11, a rotor 13 that rotates on the outer periphery of the stator 11, a coil 14 that is wound between the stator 11, and a rotor 13. A bearing 15, a yoke 16 surrounding the rotor 13, and a base (bottom plate) 17 are provided. In FIG. 2, the description of the coil 14, the bearing 15, and the base 17 is omitted for easy understanding.

  The stator 11 is for guiding the magnetic flux of the excited coil 14 to the magnetized region of the rotor 13. The stator 11 includes first to third stator portions (11a to 11c) made of three prismatic rod-shaped members and a support shaft 11d. The stator 11 is made of, for example, a soft magnetic material. The first to third stator portions 11a to 11c are formed integrally with the support shaft 11d. The three first to third stator portions 11a to 11c are arranged radially at regular intervals in the axial direction of the support shaft 11d so that the angle formed between them is 60 degrees around the support shaft 11d. Is done. A support shaft 11d is arranged at the center of the three first to third stator portions 11a to 11c. When the coil 14 is excited, the end portions of the first to third stator portions 11a to 11c facing the inner peripheral surface of the rotor 13 are respectively magnetic poles a (a pole), as shown in FIG. A magnetic pole b (b pole) and a magnetic pole c (c pole) are formed. The support shaft 11d also serves as the central axis of rotation of the rotor 13.

  The rotor 13 is an outer rotor that rotates around the outer circumference of the stator 11 by a rotational torque generated by a magnetic force between the rotor 11 and the stator 11. The rotor 13 is made of a hollow cylindrical member. The rotor 13 is made of a magnet material such as rare earth / iron. As shown in FIG. 2, the rotor 13 has four magnetic poles (N1, N2, S1, S2) that are alternately different in polarity in the circumferential direction and magnetized in the radial direction. The four magnetic poles (N1, N2, S1, S2) are provided at equal intervals in the circumferential direction. The first to third stator portions 11 a to 11 c are disposed in the hollow portion 13 a of the rotor 13, and the first to third stator portions 11 a to 11 are arranged on the four magnetic poles (N 1, N 2, S 1, S 2) of the rotor 13. It is arrange | positioned so that the front-end | tip part of 11c may oppose. Near the edge of the hollow portion 13a of the rotor 13 on the base 17 side (left side in FIG. 1), a bearing cutout portion 131a is formed.

The coil 14 magnetizes the stator 11 when excited. The coil 14 is directly wound around the support shaft 11d. Therefore, the electromagnetic actuator 10 of the present embodiment does not include a coil bobbin. The coil 14 includes a first coil 14a wound around a support shaft 11d between the first stator portion 11a and the second stator portion 11b, a second stator portion 11b, and a third stator portion 11c. And the second coil 14b wound around the support shaft 11d. A positive or negative current is applied to the coil 14. The stator 11 is provided with an insulating coating.
Since the two first and second coils 14a and 14b can be wound around the spindle 11d by the same machine at the same time, the number of assembling steps can be reduced and the manufacturing cost can be reduced. Further, since the coil 14 is wound directly on the support shaft 11d instead of the coil bobbin, the winding diameter of the coil 14 can be reduced, so that the electromagnetic actuator 10 can be reduced in the radial direction and the winding space can be reduced. The coil resistance can be kept low, and the efficiency of the coil 14 is improved.

  The bearing 15 supports the rotor 13 rotatably around the support shaft 11d. The bearing 15 is made of, for example, a material having excellent sliding characteristics. The bearing 15 includes a first bearing 15a that supports the end of the rotor 13 on the base 17 side, and a second bearing 15b that supports the end on the opposite side. The first bearing 15 a is fixed to the bearing notch 131 a of the hollow portion 13 a of the rotor 13 and is rotatably inserted into the shaft support portion 17 a of the base 17. The second bearing 15b is fixed to the inner peripheral surface in the vicinity of the end of the hollow portion 13a of the rotor 13 opposite to the base 17 and is rotatably fitted to the support shaft 11d. When the rotor 13 is a rubber sheet magnet, the bearings 15a and 15b may be fixed to the yoke 16. In this case, the sheet magnet is fixed to the yoke 16.

  The yoke 16 prevents the magnetic flux from leaking. The yoke 16 is made of a cylindrical member. The yoke 16 surrounds the rotor 13 and is fixed to the outer periphery of the rotor 13. The yoke 16 is formed of, for example, a soft magnetic material.

  The stator 11 is fixed to the base 17 by inserting the support shaft 11d into the center portion, and the rotor 13 is rotatably supported via the first bearing 15a. A convex shaft support portion 17a into which the support shaft 11d is fitted in the central shaft hole 171a and the first bearing 15a is rotatably inserted and the coil 14 is wound on the base 17. A pin 17b is formed.

  Here, the rotation operation of the rotor 13 of the electromagnetic actuator 10 will be described with reference to FIG. In FIG. 4, the rotor 13 rotates in the clockwise direction. In FIG. 4, the coil 14 is not shown for easy understanding.

  The state shown in FIG. 4A is a state in which the electromagnetic actuator 10 is excited by applying, for example, a positive current to the first coil 14a and applying a negative current to the second coil 14b, for example. By this excitation, the magnetic pole a (a pole) of the first stator portion 11a becomes the S pole, the magnetic pole b (b pole) of the second stator portion 11b becomes the N pole, and the magnetic pole c ( c pole) is the S pole. In this state, an attractive force is generated between the magnetic poles S1 and S2 of the rotor 13 and the magnetic pole b magnetized to the N pole of the second stator portion 11b, and the rotor 13 is stably stopped.

  Next, when a negative current is applied to the first coil 14a and a negative current is applied to the second coil 14b at the rotational position of the rotor 13 shown in FIG. As shown in FIG. 3, the magnetic pole a of the first stator portion 11a is an N pole, and the magnetic pole c of the third stator portion 11c is an S pole. In this state, an attractive force is generated between the magnetic pole N1 and magnetic pole N2 of the rotor 13 and the magnetic pole c magnetized on the S pole of the third stator portion 11c, and at the same time, the magnetic poles N1, N2 and N pole of the rotor 13 are magnetized. A repulsive force is generated between the magnetic pole a and the magnetic pole a, and an attractive force is generated between the magnetic poles S1 and S2 of the rotor 13 and the magnetic pole a magnetized to the N pole of the first stator portion 11a. As a result, rotational torque is generated in the rotor 13 so as to rotate in the clockwise direction, and the rotor 13 rotates by 45 degrees in the clockwise direction, resulting in the state shown in FIG.

  Next, when excitation is performed by applying a negative current to the first coil 14a and a positive current to the second coil 14b at the rotational position of the rotor 13 shown in FIG. 4B, FIG. 4C. As shown, the magnetic pole a of the first stator portion 11a is N-pole, the magnetic pole b of the second stator portion 11b is S-pole, and the magnetic pole c of the third stator portion 11c is N-pole. In this state, an attractive force is generated between the magnetic poles N1 and N2 of the rotor 13 and the magnetic pole b magnetized to the S pole of the second stator portion 11b. At the same time, a repulsive force is generated between the magnetic poles N1 and N2 and the magnetic pole c magnetized to the N pole. Further, an attractive force is generated between the magnetic poles S1 and S2 and the magnetic pole c. As a result, rotational torque is generated in the rotor 13 so as to rotate in the clockwise direction, and the rotor 13 is further rotated by 45 degrees in the clockwise direction, so that the state shown in FIG.

  Next, when excitation is performed by applying a positive current to the first coil 14a and a positive current to the second coil 14b at the rotational position of the rotor 13 shown in FIG. 4C, FIG. As shown, the magnetic pole a of the first stator portion 11a is an S pole, and the magnetic pole c of the third stator portion 11c is an N pole. In this state, an attractive force is generated between the magnetic poles N1 and N2 of the rotor 13 and the magnetic pole a magnetized to the S pole of the first stator portion 11a, and at the same time, repulsion is generated between the magnetic poles S1 and S2 and the magnetic pole a. Power is generated. Further, an attractive force is generated between the magnetic poles S1 and S2 of the rotor 13 and the magnetic pole c magnetized by the N pole of the third stator portion 11c. Thereby, rotational torque is generated in the rotor 13 so as to rotate in the clockwise direction, and the rotor 13 is further rotated by 45 degrees in the clockwise direction, and the state shown in FIG.

  Next, when excitation is performed by applying a positive current to the first coil 14a and a negative current to the second coil 14b at the rotational position of the rotor 13 shown in FIG. 4D, FIG. As shown, the magnetic pole a of the first stator portion 11a is an S pole, the magnetic pole b of the second stator portion 11b is an N pole, and the magnetic pole c of the third stator portion 11c is an S pole. In this state, an attractive force is generated between the magnetic poles S1 and S2 of the rotor 13 and the magnetic pole b magnetized to the N pole of the second stator portion 11b. At the same time, a repulsive force is generated between the magnetic poles S1 and S2 and the magnetic pole c. Further, an attractive force is generated between the magnetic poles N1 and N2 and the magnetic pole c. Thereby, rotational torque is generated in the rotor 13 so as to rotate in the clockwise direction, and the rotor 13 is further rotated by 45 degrees in the clockwise direction, and the state shown in FIG. The rotor 13 is rotated 180 degrees in the clockwise direction from the state shown in FIG.

  Further, as described with reference to FIGS. 4A to 4E, when the excitation of the first coil 14a and the second coil 14b is repeated, the rotor 13 continues to rotate in the clockwise direction. When the rotor 13 is to be rotated counterclockwise from the state shown in FIG. 4E, the operations described in FIGS. 4A to 4E are performed in reverse. What is necessary is just to excite the 1st coil 14a and the 2nd coil 14b in the order from FIG. 4 (E) to FIG. 4 (A).

  A sector driving apparatus using the electromagnetic actuator 10 will be described with reference to FIG. The drive device for this sector is used in a small camera mounted on a portable device. The sector drive device 20 includes a pair of substrates 21 a and 21 b, a pair of sectors 22 a and 22 b, and an engagement pin 23. A drive pin 24 projects from the rotor 13 (yoke 16) of the electromagnetic actuator 10 in parallel with the support shaft 11d. The first substrate 21a includes a shutter opening 211a, a convex portion 212a, and a support shaft hole 213a. The second substrate 21b includes a shutter opening 211b, a convex hole 212b, a support hole 213b, a drive pin notch 214b, and an engaging pin long hole 215b. The first sector 22a is formed with an engagement pin hole 221a, a support shaft hole 222a, and a drive pin hole 223a. The second sector 22b is formed with a convex hole 221b and an engagement pin notch 222b.

  The first substrate 21a and the second substrate 21b are combined so as to face each other, and the sectors 22a and 22b, the electromagnetic actuator 10 and the engagement pin 23 are arranged between the first substrate 21a and the second substrate 21b. Is done.

  The support shaft 11d of the electromagnetic actuator 10 is inserted into the support hole 213a of the first substrate 21a, the support hole 222a of the first sector 22a, and the support hole 213b of the second substrate 21b. The drive pin 24 of the electromagnetic actuator 10 is inserted into the drive pin hole 223a of the first sector 22a and is disposed in the drive pin notch 214b of the second substrate 21b. The engagement pin 23 is inserted into the engagement pin hole 221a of the first sector 22a, and the engagement pin notch 222b of the second sector 22b and the long hole for the engagement pin of the second substrate 21b. 215b. The convex portion 212a of the first substrate 21a is inserted into the convex portion hole 221b of the second sector 22b and the convex portion hole 212b of the second substrate 21b.

  In the drive device 20 of this sector, when the rotor 13 is rotated in the clockwise direction in FIG. 5, the first sector 22a is rotated clockwise around the support shaft 11d via the drive pin 24. As the first sector 22a rotates in the clockwise direction, the engagement pin 23 engages with the engagement pin notch 222b of the second sector 22b, thereby causing the second sector 22b to rotate counterclockwise. Rotate. As described above, the shutter openings 211a and 211b are closed by rotating the first sector 22a and the second sector 22b in a direction in which they approach each other.

  Then, when the rotor 13 is rotated counterclockwise in FIG. 5, the first sector 22a is rotated counterclockwise around the support shaft 11d via the drive pin 24. As the first sector 22a rotates counterclockwise, the engagement pin 23 engages with the engagement pin notch 222b of the second sector 22b, and the second sector 22b moves clockwise. Rotate. Thus, the shutter openings 211a and 211b are opened by rotating the first sector 22a and the second sector 22b away from each other. In this manner, in the sector drive device 20, the sectors 22a and 22b are opened and closed.

  Here, a control circuit for controlling the electromagnetic actuator 10 in the sector drive device 20 will be described with reference to FIG. As shown in FIG. 6, the control unit 30 includes a CPU (Central Processing Unit) 31, a memory 32, and a driver 33. The CPU 31 performs control and arithmetic processing of the entire electromagnetic actuator 10. The memory 32 stores a program and control information for controlling the electromagnetic actuator 10. In response to a control signal from the CPU 31, the driver 33 energizes the coils 14a and 14b by passing a positive or negative drive current in pulses. An operation button 34 is connected to the CPU 31.

  When the operation button 34 is pressed, the CPU 31 instructs the driver 33 to output a positive current or a negative current in order to drive the electromagnetic actuator 10. The driver 33 supplies a positive current or a negative current to the coils 14a and 14b of the electromagnetic actuator 10 in accordance with the instructions. In this way, by energizing the coils 14a and 14b of the electromagnetic actuator 10 and rotating the rotor 13 of the electromagnetic actuator 10 in the clockwise direction or the counterclockwise direction as described with reference to FIG. 22b is driven and a shutter operation is performed.

  A lens driving device using the electromagnetic actuator 10 will be described with reference to FIGS. The same parts as those already described are denoted by the same reference numerals and description thereof is omitted. The lens driving device 40 includes a worm gear 42 and a lens holder 43 on a substrate 41. The worm gear 42 is provided on the substrate 41 by the support portion 45 so as to be rotatable about the shaft 42a. The lens holder 43 has a lens 44 at the center. A gear 43 a is provided on a part of the outer periphery, and the gear 43 a meshes with the worm gear 42. As the worm gear 42 rotates, the lens holder 43 moves in the optical axis direction while rotating, and focus adjustment is performed.

  As shown in FIG. 8, the worm gear 42 incorporates the electromagnetic actuator 10 so that the worm gear 42 can rotate. A yoke 16 is provided on the outer periphery of the rotor 13, and a worm gear 42 is fixed to the outer periphery of the yoke 16. Further, as shown in FIG. 9, a cam shaft 50 for moving the lens by a cam may be provided on the outer periphery of the yoke 16 instead of the worm gear 42.

  As described above, in the electromagnetic actuator of the present embodiment, the two first and second coils 14a and 14b are wound between the three first to third stator portions 11a to 11c on the support shaft 11d. Therefore, it is small in the axial direction, that is, it can be thinned.

  Moreover, in this Embodiment, since the 1st-3rd stator parts 11a-11c are comprised by the prismatic rod-shaped member, a structure can be simplified and the cost at the time of manufacture is aimed at. Can do.

  Further, in the present embodiment, the stator 11 is integrally formed (directly connected) with the support shaft 11d and the first to third stator portions 11a to 11c so as to become one component. Variations in component accuracy and assembly accuracy can be reduced. As a result, the rotation stop position accuracy of each pulse of the rotor 13 of the electromagnetic actuator 10 can be improved, the torque unevenness at each point of the rotation angle 360 degrees of the rotor 13 can be reduced, and the electromagnetic actuator 10 It is possible to reduce the quality variation between the products.

  Further, in the present embodiment, since the support shaft 11d and the first to third stator portions 11a to 11c are directly connected to each other, there is no magnetic separation and a large cross-sectional area in a portion where the magnetic flux is most concentrated. 11d can be arranged, and the magnetic resistance can be reduced. Therefore, the motor efficiency is improved. Further, by incorporating the support shaft 11d into the magnetic path, the support shaft 11d can be used as a magnetic circuit, so that the diameter of the electromagnetic actuator 10 can be reduced.

  In addition, since the drive device according to the present embodiment includes the electromagnetic actuator as described above, it is possible to reduce the thickness, improve the accuracy of sector opening / closing control, and reduce variation in quality among products. .

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the present embodiment, the example in which the three stator portions 11a to 11c and the support shaft 11d are integrally formed has been described. However, the three stator portions 11a to 11c and the support shaft 11d are formed as separate bodies, and the support is supported. You may make it fix the three stator parts 11a-11c to the axis | shaft 11d. Even in this case, since the support shaft 11d can be used as a common alignment reference for the three stator portions 11a to 11c, it is possible to reduce variations in component accuracy and assembly accuracy between the stator portions.

  In the present embodiment, an example using three stator portions 11a to 11c and two coils 14 has been described. However, the number of stator portions is not limited to three, and may be more or less than three. The number of coils wound between the stator portions is not limited to two, and may be one or three or more according to the number of stators.

  Moreover, although this embodiment demonstrated the example which forms the three stator parts 11a-11c from a prismatic rod-shaped member, the shape of the stator parts 11a-11c is not limited to a prismatic rod-shaped member, and is a cylindrical rod-shaped member. It may be a member, a cross-shaped member, or a member whose tip serving as a magnetic pole faces the magnetic pole on the inner peripheral surface of the rotor 13.

  Further, in the present embodiment, an example in which the rotor 13 is magnetized with four poles inside has been described, but the number of poles of the rotor 13 may be more or less than four.

  Further, in the present embodiment, the example using the base 17 has been described, but the base 17 is not used by using the first bearing 15a that is directly inserted into the support shaft 11d like the second bearing 15b. You may do it.

  In this embodiment, the example in which the yoke 16 is fixed to the rotor 13 and rotated is described. However, the yoke 16 is not necessarily fixed to the rotor 13 and may be fixed to the base 17, for example.

  Moreover, although this embodiment demonstrated the example which winds the coil 14 to the spindle 11d directly, you may make it use a coil bobbin.

  Moreover, although this embodiment demonstrated the example which uses the bearing 15 which consists of a member with the outstanding sliding characteristic for the bearing 15, you may use a rolling bearing.

  Further, in the present embodiment, an example in which the electromagnetic actuator 10 is a stepping motor has been described. However, the present invention is not limited to a stepping motor, and can be applied as a swing motor that is provided with a determining member and whose rotation is limited within a certain range. .

  In the present embodiment, the example in which the electromagnetic actuator 10 is used for a driving device of a sector of a small camera mounted on a portable device has been described. However, the present invention is not limited to this. It can also be used for vibration generators and the like, and can also be used for copiers, facsimiles, printers, and the like.

It is a partial sectional view showing composition of an electromagnetic actuator concerning an embodiment of the present invention. It is a schematic plan view of the electromagnetic actuator shown in FIG. It is arrow sectional drawing in the X-X 'line | wire of FIG. It is explanatory drawing for demonstrating the rotation principle of the rotor in the electromagnetic actuator which concerns on embodiment of this invention. It is a disassembled perspective view of the drive device of the sector provided with the electromagnetic actuator which concerns on embodiment of this invention. It is a block diagram of a control circuit for controlling an electromagnetic actuator concerning an embodiment of the present invention. It is a front view of the drive device of the lens provided with the electromagnetic actuator concerning the embodiment of the present invention. It is sectional drawing of the principal part of FIG. It is a perspective view of the principal part of the drive device of the lens using the cam provided with the electromagnetic actuator which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electromagnetic actuator 11 Stator 11a-11c 1st-3rd stator part 11d Spindle 13 Rotor 14 Coil 14a, 14b 1st, 2nd coil 15 Bearing 15a, 15b 1st, 2nd bearing 16 Yoke 17 Base 20 Sector drive units 22a, 22b first and second sectors 23 engaging pins

Claims (4)

A stator composed of a support shaft and a plurality of rod-shaped members formed integrally with the support shaft and spaced apart in the axial direction of the support shaft so as to form a fixed angle with respect to the support shaft. When,
A coil that is wound directly between the plurality of rod-shaped members on the support shaft and magnetized by exciting the end of the rod-shaped member ;
A plurality of magnetic poles in the circumferential direction is formed in a cylindrical shape, said plurality of magnetic poles and the stator so that the ends of the plurality of bar-like members are opposed are arranged therein, positive about said support shaft An electromagnetic actuator comprising a rotor that can rotate in both reverse directions . 2. The electromagnetic actuator according to claim 1 , wherein the support shaft constitutes a magnetic circuit together with the plurality of rod-shaped members. In Claim 1 or 2 , the plurality of bar-shaped members are three bar-shaped members, and the three bar-shaped members are arranged so as to form an angle of 60 degrees around the support shaft,
The rotor has four magnetic poles having different polarities alternately in a circumferential direction. The electromagnetic actuator of any one of Claims 1 thru | or 3 is provided, The yoke which prevents magnetic flux leakage is integrally provided in the outer periphery of the said rotor, and the transmission which transmits the driving force of the said rotor to the outer periphery of this yoke The drive device characterized by the above-mentioned.

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