JP2006094660A - Electromagnetic actuator and light-quantity adjusting device using this actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic actuator capable of improvement in magnetic efficiency, size reduction, and large output torque, and a light-intensity adjusting device capable of attaining size reduction. <P>SOLUTION: This device includes a substrate frame made by a non-magnetic body, a cylindrical magnet rotor supported at the substrate frame so as to be rotated and having poles around an outerperiphery, a pair of magnetism induction members for forming the poles facing the poles of the magnet rotor, and an excitation coil for generating magnetism at the pair of magnetism induction members respectively. Besides, the pair of magnetism induction members is constituted by a soft magnetism member in a roughly U shape having top end bent pieces at both the edge portions, and the respective top end bent pieces have a pole forming portion and a coil winding portion in a rotational axial direction of the magnet rotor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an electromagnetic actuator in which a magnetic induction member connected to an electromagnetic coil is opposed to a magnet rotor magnetized on an NS pole, and the rotor is reciprocated in a predetermined angle range by applying forward and reverse currents to the electromagnetic coil. Incorporated into digital cameras and other optical equipment,
The present invention relates to an electromagnetic actuator used as a driving device for a shutter, a diaphragm device or an autofocus mechanism, and a light amount adjusting device using the electromagnetic actuator.

  In general, this type of electromagnetic actuator is incorporated in a small device such as a camera device and widely used to drive a functional component having a small displacement with a relatively small torque. For example, in a camera device, it is used as a driving means for a light quantity regulating device such as a shutter blade or a diaphragm blade, and its structure is reciprocated by a predetermined angle by a magnetic field generated by applying a current to a coil of a magnet rotor magnetized on an NS pole. I try to rotate. The magnetic field generated by this coil is a structure in which a coil is wound around the magnet rotor to face the permanent magnet, and an iron core is provided at the center of the coil, and one end of this iron core is opposed to the magnetic pole of the magnet rotor. Each structure is known.

  The present invention relates to an actuator in which a coil is wound around the other end of a soft magnetic member having the latter one end opposed to a magnetic pole of a magnet rotor. Conventionally, such an actuator has been proposed as shown in FIG. 13, for example, as shown in Patent Document 1, and FIG. 14 is a sectional view of the assembled state. That is, the magnet rotor PG1 is rotatably arranged at the center of the base plate PH1 such as resin, and a pair of soft magnetic members (iron core members) PF1 and PF2 facing the periphery of the rotor are arranged. The iron core members PF1, PF2 are provided with two bent pieces PF5, PF6 and PF3, PF4 as shown in FIG. 13, respectively, and one bent piece PF5 (PF6) is an outer peripheral surface of the magnet rotor PG1. And the other bent piece PF3 (PF4) is disposed at a position that fits in the center of the coil PE1 (PE2). The coil PE1 (PE2) is fixed to a cover frame PC1 attached to the ground plane PH1.

Therefore, in order to form a magnetic circuit with the magnetic fields generated in the two coils, the bent pieces PF3 and PF4 positioned at the centers of the coils PE1 and PE2 are magnetically coupled by the coupling yoke PB1. The connecting yoke PB1 is formed of a U-shaped bent piece of soft magnetic member, and the tip portions PB2 and PB3 are joined to the bent pieces PF3 and PF4 at the center of each coil, respectively, and bent by this joining. The magnetic field generated in the pieces PF3 and PF4 is transmitted to the connecting yoke PB1, and a magnetic circuit is formed around the magnet rotor PG1. PA1 and PA2 shown in the figure are screw members for fixing the cover frame PC1 incorporating the connecting yoke and the coil to the ground plane PH1 incorporating the iron core member.
JP 2001-352741 A

  As described above, when a pair of soft magnetic members are arranged at positions facing the magnetic poles of the magnet rotor, and a coil is wound around these members to form magnetic pole portions having N-S conflicts, the conventional structure has the following problems. Will occur.

  That is, when an NS magnetic circuit is configured by a pair of soft magnetic members arranged around the rotor, conventionally, a bent piece of the soft magnetic member is provided at a position close to the outer periphery of the rotor as in Patent Document 1 described above. A magnetic pole part is formed, a second bent piece is provided at a distance from the bent piece, and a coil is wound around the bent piece. A pair of such soft magnetic members are arranged around the rotor, and the two soft magnetic members are connected by a U-shaped yoke (soft magnetic member) to form a magnetic circuit.

  Accordingly, the first and second soft magnetic members are arranged on the substrate frame to form a magnetic pole portion, and the two magnetic pole portions are connected by a yoke member to form a magnetic circuit around the rotor. A loop-shaped magnetic circuit is formed by connecting the two. In such a configuration, since the soft magnetic member (iron core member) positioned at the center of the coil and the yoke member cannot be integrally formed in the manufacture, the connection by the soft magnetic member is not necessarily produced. There is a problem that the magnetic torque obtained by the magnetic circuit cannot be obtained because of high resistance and poor magnetic efficiency. This is because the bent piece that forms the magnetic pole in the outer circumferential direction of the rotor and the bent piece that winds the coil across the winding area of the coil are arranged on the outer side. Thus, the problem arises from the fact that the coil cannot be fitted unless the yoke member for constituting the magnetic circuit is constituted by another member.

  Also, since the structure is arranged in the order of the bent piece (magnetic pole part) of the soft magnetic member and the bent piece around which the coil is wound on the outer side in the outer circumferential direction centering on the rotor, it is natural that the device becomes large in diameter and large. Therefore, it is not suitable for small devices such as the latest digital cameras. At the same time, in order to reduce the size of the apparatus in the conventional structure in which the rotor is the core and the magnetic pole forming piece (bending piece), the coil and the coil iron core (bending piece for winding the coil) are arranged on the outer periphery of the rotor The magnet rotor must be configured with a small diameter, and it is difficult to control and secure manufacturing accuracy. This is because, for example, when the position and shape of the magnetic pole forming portion of the soft magnetic member vary in production, the influence of the cylindrical rotor is small compared to the large diameter when the cylindrical rotor is small, and the control current applied to the coil varies. This is because when it occurs, the same applies.

  Therefore, the present invention aims to improve the efficiency of the magnetic circuit when applying a rotational force to the magnet rotor by the magnetic field generated in the exciting coil, and to provide a small-sized electromagnetic actuator having a large output torque. An object is to provide a small and compact light amount adjustment device.

The present invention adopts the following configuration in order to solve the above problems.
A non-magnetic substrate frame, a cylindrical magnet rotor rotatably supported on the substrate frame and having a magnetic pole on the outer periphery, and a pair of magnetic induction members forming a magnetic pole opposed to the magnetic pole of the magnet rotor And an exciting coil for generating magnetism in each of the pair of magnetic induction members. The pair of magnetic induction members are constituted by substantially U-shaped soft magnetic members having tip bent pieces at both ends, and each tip bent piece and a magnetic pole forming portion in the rotation axis direction of the magnet rotor. A coil winding portion.

  The exciting coil is arranged in the coil winding portion of the tip bent piece, and the magnetic rotor is arranged so that the magnetic pole formed on the outer periphery and the magnetic pole forming portion of the tip bent piece face each other with a gap. did. The magnetic pole forming portions of the magnetic induction member are arranged opposite to each other across the rotating shaft of the magnet rotor, and the pair of magnetic pole forming portions is located at a position where the other is displaced by a predetermined angle with respect to a straight line passing through one of the rotating shafts. It arrange | positioned so that the said magnet rotor might be opposed.

  The board frame is made of a synthetic resin material. The board frame has a bearing hole for supporting the rotating shaft of the magnet rotor, an engagement hole for passing the tip bent piece of the magnetic induction member, and this engagement. A coil frame around which the exciting coil is wound is integrally formed around the hole.

  In the present invention, a substantially U-shaped soft magnetic member is arranged around a magnet rotor rotatably arranged on a substrate frame, and a magnetic pole forming portion and a coil winding are formed on the bent pieces at both ends of the member along the rotation axis direction of the rotor. By providing the turning portion, the pair of magnetic poles formed on the outer periphery of the rotor can be configured with a single soft magnetic member. Therefore, compared to the conventional case where a plurality of members are joined together to form a magnetic circuit, there is less magnetic loss at the joined portion, and the magnetic torque can be applied to the magnet rotor as much as possible. Can be provided.

  In addition, since the magnetic induction member forms the coil winding part and the magnetic pole forming part along the rotation axis direction of the magnet rotor, the coil and the magnet rotor are arranged so as to overlap each other in this axial direction. The apparatus can be reduced in size and size without reducing the outer diameter of the magnet rotor, and the outer diameter of the magnet rotor is secured, so that the control thereof is easy.

  Further, according to the present invention, the magnetic induction member is arranged in a predetermined angular range around the magnet rotor, so that the magnetic pole of the magnet rotor is held in the open region or the closed region by the absorption action of the magnetic induction member when the apparatus is not used. It becomes possible. Therefore, the blades of the light amount adjusting device can be held in a closed state or an open state without using a close spring or the like.

Hereinafter, the present invention will be described in detail based on the preferred embodiments shown in the drawings.
FIG. 1 is a perspective view of a camera light amount adjusting device using an electromagnetic actuator of the present invention, FIG. 2 is an exploded view of the electromagnetic actuator device, and FIG. 8 is a sectional view of the assembled state.

  First, a camera light amount adjusting device using an electromagnetic actuator, which will be described later, will be described with reference to FIG. The illustrated one is composed of a ground plate (substrate) SG incorporated in a lens barrel of a camera device by a shutter device, shutter blades SB1 and SB2 arranged on the ground plate SG, and an electromagnetic actuator AX that drives the blade to open and close. ing. The base plate SG is a flat substrate having an optical path opening SG1 at the center, and is formed by molding of a resin material, for example, and the outer diameter is configured according to the shape of a lens barrel such as a camera device to be incorporated. In particular, by reducing the outer diameter of the main plate, it can be incorporated into a small device such as a mobile phone. In addition, since the lens barrel such as a normal photographing lens is cylindrical, the main plate protrudes to the outside. No circular shape is preferred.

  Therefore, shutter blades SB1 and SB2 for opening and closing the opening are disposed in the optical path opening SG1 formed in the base plate SG. This blade is composed of one sheet or two or more sheets as shown. The shutter blades SB1 and SB2 are rotatably supported by pins SG2 and SG3 whose base ends are planted on the base plate SG, respectively, and the blade tips open and close the optical path opening SG1. The blades may be arranged on the base plate SG so as to be rotatable by a pin, or may be slidable so as to pass through the opening SG1. The blades arranged in this way are connected to the driving device. SB3 and SB4 shown in the figure are slit grooves formed in a direction substantially perpendicular to the rotation trajectory of the blades, and a rotor driving arm AB4 to be described later is provided. Mated.

The drive device will be described with reference to FIG.
The electromagnetic drive device of the present invention includes a substrate frame AE, a magnet rotor AB pivotally supported on the substrate frame, and a magnetic induction member that forms a magnetic pole (magnetic circuit) at a position facing the magnetic pole of the magnet rotor. It is comprised by AF and exciting coil AD which provides magnetism to this magnetic induction member.

  The substrate frame AE is configured to incorporate the above-described components, and each component is assembled between a pair of upper and lower plate members. The substrate frame AE may be formed of a non-magnetic material such as resin, and one of the frame configurations may be used as the substrate of the light amount adjusting device described above. The illustrated one includes a lower frame AE and an upper frame AA, and the upper frame AA includes a cover member having a side wall around it.

  Next, the magnet rotor AB is constituted by a cylindrical permanent magnet AB2 having a rotation axis AB1 at the center. The outer periphery of the permanent magnet AB2 is polarized and magnetized to two poles (N-S pole), and a rotary shaft AB1 is integrally provided at the center thereof, and a drive arm AB3 is integrally formed on the rotary shaft. In the magnet rotor AB, for example, a magnetic material is fired into a hollow cylindrical shape by sintering, and a rotary shaft AB1 and a drive arm AB3 are integrally formed thereon by resin insert molding. Then, the outer periphery is polarized and magnetized into two poles to form an NS pole. The drive arm AB3 is integrally provided with a drive arm AB4 that engages with the slit grooves SB3 and SB4 formed in the shutter blades SB1 and SB2.

  The magnet rotor AB configured as described above is rotatably supported on the substrate frame. The illustrated one has a bearing hole AE1 in the lower frame AE and a bearing hole AA2 in the upper frame AA, and both ends of the rotation shaft AB1 of the rotor AB are fitted into the bearing holes. The lower frame AE constituting the above-described substrate frame is formed of a nonmagnetic material such as resin, and the coil frames AE4 and AE5 and the protrusions AE2 and AE3 are integrally provided. The coil frames AE4 and AE5 are wound with exciting coils which will be described later, and the protective plates AC of the exciting coils are locked to the protrusions AE2 and AE3. A magnetic induction member AF having the following structure is attached to the lower frame AE.

  The magnetic induction member AF has two magnetic pole forming portions AF1a, AF2a and a coil winding portion AF1b which are opposed to each other by forming a small gap (magnetic gap) with the magnetic pole of the magnet rotor AB rotatably attached to the substrate frame. It is comprised with the substantially U-shaped soft magnetic member which has AF2b.

  That is, both ends of a soft magnetic material plate member made of iron or the like are bent to provide the end bent pieces AF1 and AF2 at both ends. The pair of bent pieces AF1 and AF2 are formed at intervals slightly larger than the outer diameter of the magnet rotor and are fitted into engagement holes AE8 and AE9 (see FIG. 8) formed in the lower frame AE. The engagement holes AE8 and AE9 are provided at the centers of the coil frames AE4 and AE5.

  The magnetic induction member AF has a connecting portion AF3 for connecting the bent pieces AF1 and AF2. Therefore, the magnetic circuit is configured so that when the magnetic pole forming part AF1a of the bent piece AF1 has the N pole, the magnetic pole forming part AF2a of the other bent piece AF2 has the S pole. Further, coil winding portions AF1b and AF2b and magnetic pole forming portions AF1a and AF2a are arranged along the rotation axis AB1 of the rotor in the bent pieces AF1 and AF2. At this time, as shown in FIG. 8, a space L shown in the figure is provided between the lower frame AE and the magnet rotor AB, and this space becomes a space around which the exciting coil is wound.

Therefore, the exciting coil AD has a hole AD1 that fits in the coil frames AE4 and AE5 in the center, and is composed of a coil wire wound in the circumferential direction of FIG. 2, and this coil is fitted and supported on the coil frames AE4 and AE5. Is done. Then, the coil AD is wound around the outer periphery of the bent pieces AF1 and AF2 through the coil frame, and the bent pieces AF1 and AF2 are magnetized by the magnetic field generated by energizing the coils.
Due to the magnetizing action of this coil, magnetic poles facing NS are formed in the magnetic pole forming portions AF1a and AF2a at the tips of the bent pieces. The illustrated AC is a protective plate for the exciting coil AD and is provided with a hole AC1 through which the bent pieces AF1 and AF2 are inserted by a nonmagnetic material, and is in contact with the projections AE2 and AE3 formed on the lower frame AE. It is fitted and held on the peripheral side wall.

  Next, an assembling method of the actuator having such a configuration will be described. The bending pieces AF1 and AF2 of the magnetic induction member AF are press-fitted into the engagement holes AE8 and AE9 of the lower frame AE. Then, the bent piece is protected by the engagement holes AE8 and AE9 formed at the center of the coil frames AE4 and AE5 formed integrally with the lower frame AE, and the magnetic induction member AF is fixed integrally to the lower frame AE. Next, the hole AD1 of the exciting coil AD wound separately by the winding machine is fitted into the coil frames AE4 and AE5 and incorporated, and the protective plate AC is similarly fitted to the coil frames AE4 and AE5. Incorporate. Therefore, the coil AD and the protection plate AC are joined to the coil frames AE4 and AE5 with an adhesive, for example.

  Next, the lower end portion of the rotating shaft AB1 of the magnet rotor AB is fitted into the bearing hole AE1 of the lower frame AE, and the upper end portion of the rotating shaft AB1 is fitted into the bearing hole AA2 of the upper frame AA. At this time, the upper frame AA is assembled so that the drive arm AB3 protrudes from the opening AA1, and is integrated with the lower frame AE.

  The upper frame and the lower frame are joined by screws or by forming a protrusion on one side and a recess engaging the protrusion on the other side, and using elastic deformation to connect / disconnect both. Further, the exciting coil AD fixed to the substrate AE is soldered to the terminals AE6 and AE7 so that the direction of the current flowing between the lead wires at the beginning and end of winding of the coil are opposite to each other. The lead wire of the coil is temporarily fixed in the lead terminal mounting holes indicated by AE8 and AE9 in FIG. As a result, an N pole is generated on one side and an S pole is generated on the other side in the magnetic pole forming portions AF1a and AF2a during operation.

  Next, FIG. 3 is a plan view of the actuator AX assembled in the state of FIG. 2 as viewed from above. The driving arm AB3 of the magnet rotor AB protruding from the opening AA1 of the upper frame AA to the outside of the apparatus is in a solid line position. Rotating back and forth between a first position O1 in the clockwise direction (open position when the shutter is fully open) and a second position O2 (counter position where the shutter is fully closed) in the counterclockwise direction. As will be described in detail with reference to FIGS. 11 and 12, the intermediate position of the magnet rotor AB indicated by the solid line in the drawing is shown for explanation, and when the exciting coil AD of the actuator AX is in a non-energized state, no current is supplied. Depending on the position of the drive arm AB3 of the magnet rotor AB at the time of the state, it is held at the first position O1 (open position where the shutter is fully open) or the second position O2 (close position where the shutter is fully closed). The intermediate position shown does not stop at this position when passing to any position.

  Next, FIG. 4 is a plan sectional view cut at the center position of the permanent magnet AB2 of the magnet rotor AB. The arrangement relationship of the pair of bending pieces AF1 and AF2 of the magnetic induction member AF in the apparatus is as follows. The bent piece AF1 is arranged at a position displaced by an angle θ (≈18 °) in the counterclockwise direction with reference to a reference straight line passing through the central portion of the bent piece AF2 and the center of the rotation axis AB1 of the magnet rotor AB. In addition, the permanent magnet AB2 of the magnet rotor AB is magnetized in the direction indicated by the symbols N and S shown in the drawing at the top of the pole, and is N-S two-pole magnetized in this direction.

  Then, if the N magnetic pole portion of the permanent magnet AB2 is slightly displaced in the clockwise direction from the intermediate position as shown in the figure, the N magnetic pole of the permanent magnet AB2 is turned into the exciting coil AD ( 2 and FIG. 5), and the bent piece AF2 is excited to the N magnetic pole by the exciting coil AD, and magnetically repels the bent piece AF2 and is attracted to the bent piece AF1. The rotor AB continues to rotate clockwise. On the other hand, if the N magnetic pole portion of the permanent magnet AB2 is slightly displaced counterclockwise from the intermediate position, the bent piece AF1 of the permanent magnet AB2 is excited to the N magnetic pole by the exciting coil AD at this time. On the other hand, the bent piece AF2 is excited on the S magnetic pole by the exciting coil AD, magnetically repels the bent piece AF1 and is attracted to the bent piece AF2, and the magnet rotor AB continues to rotate counterclockwise. To do.

  Next, the positional relationship between the magnetic poles of the magnet rotor AB and the bent pieces AF1 and AF2 of the magnetic induction member AF will be described with reference to FIG.

  First, the magnet rotor AB is magnetized with the position indicated by NS in the drawing as the pole apex, and is attached to the substrate frame AE so as to be able to reciprocate within the range of angle α1 in the counterclockwise direction and angle α2 in the clockwise direction. . The operating angle of the rotor is determined by, for example, restricting the drive arm AB4 of the drive arm AB3 at the opening AA1 formed in the upper frame AA shown in FIG. In the illustrated example, the angles α1 and α2 are set to about 20 °, respectively, and the overall operating angle α is set to about 40 °.

  The bent pieces AF1 and AF2 are arranged at positions where the other is displaced by a predetermined angle θ with respect to a straight line connecting one of them and the rotation axis of the rotor. The illustrated angle θ is set to about 18 °. This is driven by arranging the rotor in such a way that the NS magnetization direction of the rotor and the direction connecting the rotation axis AB1 and the magnetic pole forming portions AF1a and AF2a of the bent pieces AF1 and AF2 do not coincide with each other in the reciprocating operation region. This is because detent torque is applied to the rotor at the working end of the arm.

  In this way, a pair of magnetic induction members are conventionally arranged around the rotor at positions separated by 180 °, whereas they are reciprocated left and right by being arranged at an angle smaller than 180 degrees (for example, 160 degrees) as shown in the figure. The distance between the right limit position of the rotor and the magnetic pole forming portion AF1a is shortened, and the rotor is held in the right limit region by the magnetic induction member when the coil is not energized. Similarly, the left limit region of the rotor is held in the left limit region of the magnetic pole forming part AF2a.

  FIG. 12 is an XX cross section passing through the center of the magnet rotor AB shown in FIG. 11 and is an arrangement diagram for explaining the magnetic circuit configuration of the present invention. The pair of bending pieces AF1 and AF2 of the magnetic induction member AF are connected to each other. End portions extending from both side ends of the portion AF3 are bent at a substantially right angle above the plane of the paper by bending, and at the same time, the connecting portion AF3 is formed to have a plate thickness as thin as possible by surface punching. The pair of bent pieces AF1, AF2 and the connecting portion AF3 are integrally processed by bending, or may be integrally formed by casting.

The perspective view of the light quantity adjustment apparatus for cameras using the electromagnetic actuator concerning this invention. The assembly exploded view of the electromagnetic actuator apparatus concerning a present Example. FIG. 3 is a top plan view of the apparatus of FIG. 2. Sectional drawing which cut | disconnected the apparatus of FIG. 2 in the magnet rotor center part. Sectional drawing which cut | disconnected the apparatus of FIG. 2 in the excitation coil center part. FIG. 3 is a bottom view of the apparatus of FIG. 2. FIG. 3 is a side view of the apparatus of FIG. 2. FIG. 8 is a cross-sectional view of the apparatus of FIG. FIG. 3 is a right side view of the apparatus of FIG. 2. FIG. 10 is a side sectional view of the apparatus of FIG. 9. Explanatory drawing which shows the positional relationship of the magnetic pole of the magnet rotor concerning this invention, and the bending piece of a magnetic induction member. Explanatory drawing of the magnetic circuit structure in this invention. The schematic perspective view of the light quantity adjustment apparatus using the conventional actuator. FIG. 14 is a cross-sectional view of the apparatus of FIG.

Explanation of symbols

AA Upper frame AB Magnet rotor AB3 Drive arm AB4 Drive pin AC Protection plate AD Excitation coil AE Lower frame AF Magnetic induction member AF1, AF2 Bending piece AF1a, AF1b Magnetic pole forming part AX Electromagnetic actuator

Claims (6)

A substrate frame;
A cylindrical magnet rotor rotatably supported on the substrate frame and having a magnetic pole on the outer periphery;
A pair of magnetic induction members forming a magnetic pole facing the magnetic pole of the magnet rotor;
An excitation coil for generating magnetism in each of the pair of magnetic induction members;
The pair of magnetic induction members is composed of a substantially U-shaped soft magnetic member having tip bent pieces at both ends,
Each of the tip bent pieces has a magnetic pole forming portion and a coil winding portion in the direction of the rotation axis of the magnet rotor,
The magnetic pole forming portion is disposed so as to face the magnetic pole of the magnet rotor, and the exciting coil is disposed in the coil winding portion. A substrate frame made of non-magnetic material;
A cylindrical magnet rotor rotatably supported on the substrate frame and having a magnetic pole on the outer periphery;
A pair of magnetic induction members having a predetermined interval projectingly mounted on the substrate frame;
An excitation coil for generating magnetism in each of the pair of magnetic induction members;
The pair of magnetic induction members is composed of a substantially U-shaped soft magnetic member having tip bent pieces at both ends,
The pair of tip bent pieces are arranged so as to protrude on the substrate frame, and have a magnetic pole forming portion and a coil winding portion in the rotation axis direction of the magnet rotor,
On the substrate frame, the exciting coil and the magnet rotor are arranged above in this order,
This exciting coil is arranged in the coil winding part of the tip bent piece,
An electromagnetic actuator characterized in that the magnet rotor is disposed so that a magnetic pole formed on an outer periphery and a magnetic pole forming portion of the tip bent piece are opposed to each other with a gap formed therebetween. The magnetic pole forming portions of the magnetic induction member are arranged to face each other across the rotation axis of the magnet rotor,
The pair of magnetic pole forming portions are arranged so as to face the magnet rotor at a position where the other is displaced by a predetermined angle with respect to a straight line passing through the one and the rotation axis,
2. The magnetic pole magnetized in two poles on the outer periphery of the magnet rotor is disposed so as to reciprocate within a predetermined angle range around a position equidistant from the pair of magnetic induction members. 3. The electromagnetic actuator according to 2 or 2.
The substrate frame is formed of a synthetic resin material,
The substrate frame has a bearing hole for supporting the rotating shaft of the magnet rotor,
An engagement hole for penetrating the tip bending piece of the magnetic induction member;
4. The electromagnetic actuator according to claim 1, wherein a coil frame around which the exciting coil is wound is integrally formed around the engagement hole. A main plate having an optical path opening;
A light amount adjusting member that is disposed on the base plate and regulates the optical path opening;
An electromagnetic actuator for driving the light amount adjusting member,
This electromagnetic actuator
A substrate frame;
A cylindrical magnet rotor rotatably supported by the substrate frame and having a magnetic pole on the outer periphery;
A magnetic induction member forming a magnetic pole opposite to the magnetic pole of the magnet rotor;
An exciting coil for generating magnetism in the magnetic induction member;
A substantially U-shaped soft magnetic member having bent ends at both ends constituting the magnetic induction member;
A magnetic pole forming portion formed on the pair of tip bent pieces and arranged to face the magnetic pole of the magnet rotor;
A light quantity adjusting device comprising: a coil winding portion formed on the tip bent piece and having the excitation coil wound around an outer periphery thereof. A main plate having an optical path opening;
A light amount adjusting member that is disposed on the base plate and regulates the optical path opening;
An electromagnetic actuator for driving the light amount adjusting member,
The electromagnetic actuator is
A substrate frame made of non-magnetic material;
A cylindrical magnet rotor rotatably supported on the substrate frame and having a magnetic pole on the outer periphery;
A magnetic induction member having a pair of magnetic pole forming portions that protrudes and is mounted on the substrate frame;
An exciting coil that generates magnetism in the magnetic pole forming portion of the magnetic induction member;
A substantially U-shaped soft magnetic member having bent ends at both ends constituting the magnetic induction member;
A magnetic pole forming portion formed on the pair of bent end pieces and arranged to face the magnetic pole of the magnet rotor,
The exciting coil and the magnet rotor are arranged on the substrate frame in this order,
The exciting coil is disposed at the coil winding portion of the tip bent piece, and the magnet rotor is disposed so that the magnetic pole formed on the outer periphery and the magnetic pole forming portion of the tip bent piece are opposed to each other with a gap formed therebetween. A light amount adjusting device characterized by comprising:

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