JP5265298B2 - Magnetic drive device, light amount adjusting device, and optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To firmly position a yoke with respect to a rotor magnet, while simplifying the shape of components as a whole. <P>SOLUTION: A magnetic drive device includes: the rotor magnet 1; a coil bobbin which is a coil bobbin 4 on which a coil is wound and has a through-hole in the central part thereof; the yoke which includes a bar shaped integrated material inserted into the through-hole; a pair of circular arcuate magnetic pole members 3 which are fixed to both ends of the yoke respectively; a regulation member 6 which regulates one end of the rotor magnet in a thrust direction; an upper base plate 7 which fixes the coil bobbin, the yoke and the regulation member; and a lower base plate 2 which is joined to the upper base plate and rotatably supports the other end of the rotor magnet. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a magnetic drive device that is particularly suitable for a shutter device mounted on a photographing device such as a video camera, a silver salt film still camera, or a digital still camera.

  Conventionally, as a cylindrical rotary actuator having a coil mounted in the direction of the rotation axis of a magnetized rotor magnet, one described in Patent Document 1 is known.

  In Patent Document 1, a yoke is formed in a substantially U-shaped cross section in a configuration having a main body case that rotatably supports and accommodates a rotor, and a bobbin that is arranged in the axial direction of the rotor and wound with a coil. doing. A U-shaped central portion of the yoke is inserted into the coil, and both leg portions having a substantially U-shaped cross section are arranged on the outer surface of the main body case.

In Patent Document 2, first, the yoke is formed by a straight portion inserted through the through hole of the coil bobbin and an arc-shaped portion connected to the tip of the straight portion, and the straight portion of the yoke is formed in the through hole of the coil bobbin. It is configured to be inserted. Further, the upper base plate is configured such that the coil bobbin is placed and the lower surface of the upper base plate is in contact with the upper surface of the arc-shaped portion. The upper base plate also serves as a rotor magnet bearing. In other words, the upper base plate is fixed to the base plate by a locking portion protruding from the base plate, thereby serving as a bearing for the rotor, and the straight portion is inserted and integrally fitted with the coil bobbin. The yoke is sandwiched and fixed between the upper base plate and the base plate.
Japanese Patent Laid-Open No. 10-248231 JP 2008-187832 A

  However, in Patent Document 1 described above, positioning of the arc-shaped portion of the yoke that has an important influence on the driving accuracy (the above-described substantially U-shaped cross-legged leg portions) with respect to the rotor magnet is performed on one surface (the above-described This is done only by the middle part of

  Further, in Patent Document 2, due to recent demands for miniaturization, the upper base plate plays a role of serving as a rotor bearing as well as a role of fixing a yoke integrally fitted with a coil bobbin. According to such a configuration, the parts for fixing the series of component parts must be complicated, and the processing becomes complicated.

  The present invention has been made in view of the above-described problems, and an object thereof is to make it possible to firmly position the yoke with respect to the rotor magnet while simplifying the shape of the entire component.

  In order to solve the above-described problems and achieve the object, a rotor magnet, a coil bobbin around which a coil is wound, a coil bobbin having a through hole in the center, and a rod-like integrated object inserted into the through hole A pair of arc-shaped magnetic pole members fixed to both ends of the yoke, a regulating member for regulating one end of the rotor magnet in the thrust direction, the coil bobbin, the yoke, and the regulating member. An upper base plate to be fixed, and a base plate coupled to the upper base plate and rotatably supporting the other end of the rotor magnet are provided.

  According to the present invention, it is possible to firmly position the yoke with respect to the rotor magnet while simplifying the shape of the entire component.

  Hereinafter, a preferred embodiment of a magnetic drive device of the present invention will be described with reference to the drawings.

(First embodiment)
A basic configuration of the magnetic drive device according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of components of a cylindrical magnetic drive device according to this embodiment. FIG. 2 is a perspective view after assembly of the components shown in FIG. FIG. 3 is a perspective view after assembly of the components shown in FIG.

  In FIG. 1, a rotor magnet 1 is integrally formed by fixing a magnet 1a magnetized to two poles and an arm portion 1b. A shaft hole 1c is formed at the center of the rotor magnet 1 as a center of rotation. The base plate 2 serves as a base of a cylindrical magnetic drive device and is made of a nonmagnetic material. The base plate 2 is integrally formed with a rotating shaft 2a that pivotally supports the rotor magnet 1 so that the rotor magnet 1 can rotate. The rotating shaft 2a is inserted into the shaft hole 1c of the rotor magnet 1 so that the rotor magnet 1 is positioned on the lower side. It is rotatably supported from (the other end).

  As shown in FIG. 3, the arm portion 1b of the rotor magnet 1 extends from the hole 2b of the base plate 2 to the back side of the base plate 2, and is configured to drive shutter blades that engage with the arm portion 1b. It has become.

  The coil bobbin 4 around which the coil is wound has an insertion hole (through hole) 4a penetrating through the center. In this embodiment, the yoke is a rectangular parallelepiped yoke (rod-shaped yoke) 5 that is a straight member inserted through the insertion hole 4a of the coil bobbin 4 and a pair of both ends fixed to the both ends of the rectangular parallelepiped yoke 5 by welding or the like. The magnetic pole member 3 is formed in a circular arc shape. The rectangular parallelepiped yoke 5 is not divided into a plurality of portions, and is formed as a single unit. With this configuration, the processing of the yoke portion can be simplified.

  The rectangular parallelepiped yoke 5 is inserted into the insertion hole 4a of the coil bobbin 4 and is disposed above the central axis of the magnetic pole portion 3 in FIG. Both ends of the rectangular parallelepiped yoke 5 are placed at positions corresponding to convex portions 3a and 3b of the magnetic pole portion 3 to be described later.

  At this time, a thrust retainer 6 (a regulating member that regulates one end of the rotor magnet 1 in the thrust direction) is disposed between the magnetic pole portion 3 and the coil bobbin 4. The thrust retainer 6 is disposed for the purpose of preventing the end of the rotor magnet 1 and the coil bobbin 4 from rubbing. Therefore, a member having a low sliding resistance is suitable. For example, a sheet material made of a resin material such as POM, liquid crystal polymer, or PET, or a member obtained by subjecting a metal or a metal surface to rust prevention treatment is suitable. It is still effective to perform a treatment for reducing the sliding resistance on the metal surface. Also, the end surface 1d of the rotor magnet 1 that is in sliding contact with the thrust retainer 6 has a smaller sliding friction when the contact area with the thrust retainer 6 is smaller. Therefore, it is desirable to make the end surface 1d as small as possible.

  The rectangular parallelepiped yoke 5 installed on the convex portions (convex shape portions) 3a and 3b of the magnetic pole portion 3 is fixed to the convex portions 3a and 3b by, for example, laser welding.

  FIG. 4 is a view showing a state where laser welding is performed.

  Two laser welding traces 9 are formed on one side of the rectangular parallelepiped yoke 5, and laser welding is similarly performed on the opposite side although not shown. The number of locations where laser welding is performed is the number for obtaining the required strength. At this time, it is desirable that the convex portions 3a and 3b of the magnetic pole portion 3 and the rectangular parallelepiped yoke 5 are fixed without any gap to reduce the magnetic resistance, and may be fixed by a technique called resistance welding or spot welding.

  The cover 7 (upper base plate) has a role of pressing and attaching both end portions of the rectangular parallelepiped yoke 5 inserted through the coil bobbin 4 toward the base plate 2. In this embodiment, the cover 7 is coupled to the base plate 2 by screws 8. The

  FIG. 7 is a view showing a cross section of the driving device in a state where the assembly of a series of members is completed. As described above, the cover 7 has a structure in which both ends of the rectangular parallelepiped yoke 5 are pressed from above.

  In addition, pins connected to both ends of the wound coil wire are fixed to the coil bobbin 4, and a groove portion 7 a for escaping the pin 4 b is formed in the cover 7.

  Further, the base plate 2 is further formed with a convex fitting portion 2c that fits in accordance with the interval at which the pair of magnetic pole portions 3 face each other, and the pair of magnetic pole portions 3a and 3b are fitted respectively. Positioned by the portion 2 c and incorporated into the base plate 2.

  That is, in the present embodiment, the coil bobbin 4, the rectangular parallelepiped yoke 5 inserted through the coil bobbin 4, and the magnetic pole portion 3 fixed to the rectangular parallelepiped yoke 5 are positioned with respect to the base plate 2. Moreover, since the rotating shaft 2a used as the rotation center of the rotor magnet 1 is formed in the base plate 2, the rotor magnet 1 and the magnetic pole part 3 are positioned accurately.

  When the cover 7 and the base plate 2 are coupled in such a configuration, the upper and lower ground plates surround the coil bobbin 4, the yoke (the rectangular parallelepiped yoke 5 and the magnetic pole portion 3) and the rotor magnet 1, and in the axial direction and the radial direction. These are positioned and fixed.

  Next, the configuration of the coil bobbin 4 and the pair of magnetic pole portions 3 in the present embodiment will be further described.

  FIG. 5 is a view showing the incorporation of the magnetic pole part 3, the coil bobbin 4, and the rectangular parallelepiped yoke 5, and other parts and laser welding traces are omitted for easy understanding of the features of this configuration.

  In FIG. 5A, the pair of magnetic pole portions 3 has convex portions 3a and 3b formed at the respective centers, and the coil bobbin 4 is mounted on the leg receiving portions 3c formed on both sides of the convex portions 3a and 3b. Placed. As a result, the coil bobbin 4 has a coil winding width L1 as shown in FIG.

  FIG. 6 is a view showing an example in which the convex portions 3a and 3b are not provided in the magnetic pole portion. When the convex portions 3a and 3b are not provided, if the coil bobbin 4 is to be installed without changing the facing distance between the pair of magnetic pole portions 3, the coil winding needs to be disposed inside the magnetic pole portion 3, so that FIG. As shown in a). As a result, as shown in FIG. 6B, the coil winding width becomes L2 and becomes narrower. The larger the winding width and the larger the number of coil turns, the higher the torque and efficiency of the magnetic drive device. As shown in FIG. 5, the convex portions 3a and 3b are formed on the magnetic pole portion 3, and both the legs of the coil bobbin 4 are placed on the leg receiving portions 3c on both sides of the convex portion, so that the coil winding space of the coil bobbin 4 is reduced. It can be secured greatly.

  With such a configuration, the size of the yoke in the radial direction can be suppressed without weakening the magnetic force of the coil. Therefore, the diameter of the drive device can be reduced even by the configuration in which the rectangular parallelepiped yoke 5 is suppressed by the cover 7. can do.

  The thrust retainer 6 described above is formed on a leg bobbin 3c by forming a plate-like member into a shape in which a portion that comes into contact with the convex portions 3a and 3b is cut out. It is hold | maintained by being pinched | interposed between 4 and the leg receiving part 3c. With this configuration, even if the thrust retainer 6 is incorporated, the axial thickness is not increased, and the incorporation of the coil bobbin 4 and the yoke can be used to fix the thrust retainer 6.

  Next, the operation of the thus configured cylindrical magnetic driving device will be described.

  When the coil is positively energized, since the rectangular parallelepiped yoke 5 is inside the coil, the yoke becomes an electromagnet and the pair of magnetic pole portions 3 becomes magnetic poles. Due to the poles of the arc-shaped portion, the rotor magnet 1 is attracted and repelled, rotates in a magnetically stable direction, and the arm portion 1b rotates. Further, when reverse current is applied to the coil, the pole of the yoke is reversed, the suction and repulsive force are reversed, and the arm portion 1b is rotated in the reverse direction. In this way, the direction of rotation of the rotor magnet 1 changes depending on the direction of application of current to energize the coil. As a result, the rotation direction of the arm portion 1b changes and the driving direction of the shutter blades changes. Do. The driving range of the arm portion 1b is restricted by the hole 2b of the base plate 2, or restricted by the shutter blade.

  In forward and reverse energization, the posture is maintained by detent torque even when energization is stopped. This is because the magnetic pole position (phase angle) of the magnet 1a is determined in order to perform the operation as described above, and the phase angle changes depending on the shape of the yoke (magnetic pole portion 3). In the present embodiment, the drive unit such as the arm unit 1b is stopped at two places as described above.

  FIG. 8 is a diagram showing an example of a shutter device using the magnetic drive device of the present embodiment.

  8A, in the shutter device according to the present embodiment, the base plate 2 is formed integrally with the shutter frame as shown in the figure. The shutter blade 10 is engaged with the arm portion 1 b extending from the hole 2 b of the base plate 2 to the back side of the base plate 2, and the shutter blade 10 is covered with the cover plate 11. FIG. 8B shows the shutter device 110 after assembly.

  FIG. 9 shows an example of an optical apparatus including the shutter device of FIG. 8, and in this embodiment, a digital still camera is shown. Other examples of the optical apparatus on which the above-described magnetic drive device or the shutter device 110 shown in FIG. 8 is mounted include a video camera and a silver salt film still camera.

  With the configuration as described above, the magnetic drive device of the present embodiment can make the shape of the yoke and its positioning structure with respect to the rotor magnet simple. Even in such a configuration, the outer shape of the concentric circle of the rotor magnet can be reduced without reducing the driving accuracy such as the number of turns of the coil being reduced, that is, the outer shape as a magnetic drive device can be reduced. Can be Further, when such a magnetic drive device is used in a light amount adjusting device and an optical device such as an electronic camera, a highly accurate and small device can be provided.

(Second Embodiment)
Next, another configuration example of the fixing method between the rectangular parallelepiped yoke 5 and the magnetic pole portion 3 is shown in FIG. 10 as a second embodiment.

  In FIG. 10, a concave portion 3 d (fitting portion) is formed in each of the convex portions 3 a and 3 b of the magnetic pole portion 3, and an end portion 5 a corresponding to the concave portion 3 d is also formed in the rectangular parallelepiped yoke 5. By fitting these, the rectangular parallelepiped yoke 5 and the magnetic pole part 3 are fixed. As a result, the positional accuracy can be improved and the assembly can be simplified.

  As described above, with the above-described configuration, the yoke can be firmly positioned with respect to the rotor magnet, and the component shape of the entire component can be simplified.

  Moreover, since it is possible to secure a large winding space for the coil that excites the magnetic pole portion while avoiding an increase in the size of the concentric circle of the rotor magnet, an efficient magnetic drive device can be provided.

  As a result, it is possible to improve the accuracy of the light amount diaphragm device using the magnetic drive device and the optical apparatus such as a video camera and a digital still camera using the light amount diaphragm device.

It is a disassembled perspective view which shows the drive device concerning the 1st Embodiment of this invention. FIG. 2 is a perspective view of a finished product of the drive device shown in FIG. 1. FIG. 2 is a perspective view of a back surface side of a completed product of the drive device shown in FIG. 1. It is a fragmentary figure which shows the adhering part of an arc-shaped magnetic pole part and a rectangular parallelepiped yoke. It is the perspective view and top view for demonstrating the space of a coil bobbin. It is the perspective view and top view for demonstrating the space of the coil bobbin when not using the structure of 1st Embodiment. It is sectional drawing of the completed product of the drive device shown in FIG. It is a figure which shows the shutter apparatus carrying the drive device of 1st Embodiment. It is a figure which shows the optical instrument carrying the shutter apparatus shown in FIG. It is a perspective view which shows the drive device of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor magnet 2 Base plate 3 Magnetic pole part 4 Coil bobbin 5 Rectangular yoke 6 Thrust retainer 7 Cover 8 Screw 9 Laser welding trace

Claims (8)

Rotor magnets,
A coil bobbin around which a coil is wound, and a coil bobbin having a through hole in a central portion;
A yoke made of a rod-like integral member inserted into the through hole;
A pair of arc-shaped magnetic pole members respectively fixed to both ends of the yoke;
A regulating member that regulates one end of the rotor magnet in a thrust direction;
An upper base plate for fixing the coil bobbin, the yoke and the regulating member;
A base plate coupled to the upper base plate and rotatably supporting the other end of the rotor magnet;
A magnetic drive device comprising:   The magnetic drive apparatus according to claim 1, wherein the pair of magnetic pole members and the yoke are fixed by welding.   Each of the pair of magnetic pole members is formed with a convex portion having a convex shape upward, and an end portion of the yoke is fixed on the convex shape portion. The magnetic drive device according to 1 or 2.   4. Each of the pair of magnetic pole members has concave portions formed on both sides of the convex shape portion so as to face the rotor magnet and receive a part of the coil bobbin. Magnetic drive device.   The magnetic drive device according to claim 4, wherein the restriction member is sandwiched and held between the coil bobbin and the concave portion of the pair of magnetic pole members.   A fitting part is formed in a part of the convex part of the pair of magnetic pole members, and a part of the yoke is fitted into the fitting part of the pair of magnetic pole members, thereby The magnetic drive unit according to claim 3, wherein the magnetic pole member and the yoke are positioned.   A light quantity adjusting device comprising the magnetic drive device according to any one of claims 1 to 6.   An optical apparatus comprising the light amount adjusting device according to claim 7.

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