JP2008278568A - Electromagnetic actuator and camera blade drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely hold a rotor of an electromagnetic actuator at a rest position. <P>SOLUTION: The electromagnetic actuator includes: a rotor 110 which turns between the rest position and a maximum rotation position; a first yoke 120 which can generate a magnetic suction force and a repulsion force between the external peripheral face of the rotor and itself; a first coil 130 for magnetization wound to the first yoke; a second yoke 140 which can generate a magnetic suction force and a repulsion force between the external peripheral face of the rotor and itself; and a second coil 150 for energization wound to the second yoke. The first yoke 120 generates a holding force for holding the rotor at the rest position when the first coil 130 is not applied with electricity, and generates a drive force for rotating the rotor at the maximum rotation position when the first coil 130 is applied with electricity. The second yoke 140 generates a holding force for holding the rotor at the rest position when the second coil 150 is not applied with electricity, and reduces the holding force when the second coil 150 is applied with electricity. By this, the rotor is prevented from rotating from the rest position by itself, and can smoothly rotate at the start of the rotor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic actuator that generates a driving force by an electromagnetic force, and more particularly, to an electromagnetic actuator applied when driving a shutter blade or a diaphragm blade of a camera and a blade driving device for a camera using the same.

As a conventional electromagnetic actuator mounted on a shutter device or an aperture device of a camera, an N pole and an outer peripheral surface are divided in the circumferential direction while being rotatably supported with respect to a substrate having an opening for exposure. A substantially cylindrical U-shaped first and second yoke each having a columnar rotor magnetized on the S pole and two magnetic pole portions arranged to face the outer peripheral surface of the rotor, around the first yoke A first coil for excitation wound, a second coil for excitation wound around the second yoke, and the like are formed by the first yoke, the first coil, the second yoke, and the second coil, respectively. Are known in which the rotor is rotationally driven by the magnetic force generated by the two magnetic circuits, and the holding power of the rotor is increased when no current is applied (for example, Patent Document 1). reference).
However, when the shutter blade (that is, the rotor) is activated by this electromagnetic actuator, the two coils are energized at the same time to overcome the holding force, resulting in an increase in power consumption. That is, since there is no method for reducing the holding force immediately before the operation, starting the rotor requires power consumption corresponding to the holding force and starts moving from a large holding force, so it is difficult to accelerate.
Also, in this electromagnetic actuator, even if the rotor is rotated in the other direction by energization from the rest position, if it is de-energized, the rotor returns to the original rest position (single side suction), so it is necessary to always energize during operation. There is a further increase in power consumption.

Further, as other electromagnetic actuators, which are applied to drive shutter blades, a disk-shaped rotor whose outer peripheral surface is divided into two in the circumferential direction and magnetized to N and S poles, the outer periphery of the rotor A plate-shaped first yoke having a first magnetic pole portion facing the surface, a plate-shaped second yoke having a second magnetic pole portion facing the outer peripheral surface of the rotor, and wound around two connection regions of these yokes Two magnetic circuits comprising a first coil, a second coil, etc., formed by a half of the first yoke and the second yoke, a first coil, the other half of the first yoke and the second yoke, and a second coil, respectively. There is known one in which the rotor is driven to rotate by the magnetic force generated (see, for example, Patent Document 2).
However, in this electromagnetic actuator, as described above, when starting the rotor, the two coils are energized at the same time, so that the power consumption increases. In addition, since there is no method for reducing the holding force immediately before the operation, starting the rotor requires power consumption corresponding to the holding force and starts moving from a large holding force, which makes it difficult to accelerate.

JP 2001-327143 A International Publication No. WO2002 / 043227

  By the way, an electromagnetic actuator for driving a camera blade driving device such as a shutter device or a diaphragm device mounted on a digital camera, a mobile phone, a portable information terminal, etc. A sufficient magnetic holding force (detent torque) at the time of non-energization cannot be secured. Accordingly, it becomes difficult for the electromagnetic actuator to stably hold the shutter blade or the diaphragm blade or the like at a predetermined rest position, and the shutter blade or the diaphragm blade moves freely when receiving an impact force or the like from the outside. There is a fear.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to reduce the size, weight, reduce power consumption, etc. When applied as a drive source to drive, even if it receives impact force from the outside, it can prevent these blades from moving freely, and can be held at a predetermined position. It is an object of the present invention to provide an electromagnetic actuator capable of generating a driving force so as to quickly perform a shutter operation or a diaphragm operation, and a camera blade driving device using the electromagnetic actuator.

The electromagnetic actuator according to the present invention has a magnetic attraction force between a rotor having an outer peripheral surface magnetized in N and S poles and rotating in an angular range between a rest position and a maximum rotational position, and the outer peripheral surface of the rotor. A first yoke capable of generating a repulsive force, a first coil for excitation wound around the first yoke, and a second yoke capable of generating a magnetic attractive force and a repulsive force between the outer peripheral surface of the rotor, An electromagnetic actuator comprising a second coil for excitation wound around a second yoke, wherein the first yoke generates a holding force for holding the rotor in a rest position when the first coil is de-energized, In addition, when the first coil is energized in one direction, it is formed so as to generate a driving force for rotationally driving the rotor toward the maximum rotation position, and the second yoke pauses the rotor when the second coil is de-energized. Producing a holding force to hold in position, and Is formed so as to reduce its holding power when energized Le in one direction, it is characterized in that.
According to this configuration, the magnetic circuit composed of the first yoke and the first coil is applied to generate a driving force for rotationally driving the rotor, and the magnetic circuit composed of the second yoke and the second coil Applied to create a holding force to hold in the rest position.
Thus, when one rotor is stopped at the rest position by providing one magnetic circuit for driving the rotor and the other magnetic circuit for holding the rotor, the first coil and the second coil are not energized. In this state, a strong holding force (detent torque) can be obtained. On the other hand, when starting the rotor toward the maximum rotational position, the first coil is energized to slightly deviate from the rest position. Even if it is in the position, a rotational driving force can be obtained, and further, by energizing the second coil, the holding force is weakened and the rotor can be rotated quickly.
Therefore, it is possible to prevent the rotor from rotating freely from the rest position due to an impact or the like, and when the rotor is started, the rotating operation can be smoothly performed. In addition, since less power is consumed by energizing the second coil in order to reduce the holding force, power consumption can be reduced compared to the case where both coils are energized for driving as in the prior art. it can.

In the electromagnetic actuator having the above configuration, the first yoke is formed so as to generate a holding force for holding the rotor at the maximum rotation position when the first coil is de-energized, and the second yoke is de-energized to the second coil. In this case, it is possible to adopt a configuration that is formed so as to generate a holding force that holds the rotor in the maximum rotation position.
According to this configuration, the magnetic circuit formed by the first yoke and the first coil and the magnetic circuit formed by the second yoke and the second coil are both held to hold the rotor at the maximum rotational position in a non-energized state. Since a force is generated, power consumption can be reduced as compared with a case where the rotation is held at the maximum rotational position by energization (single side suction).

The electromagnetic actuator having the above configuration includes control means for controlling energization to the first coil and the second coil, and the control means is directed to the maximum rotation position after the first yoke urges the rotor to rotate toward the rest position. The first coil is energized and controlled so as to be activated, and the second coil is energized and controlled so that the holding force for the second yoke to hold the rotor in the rest position is reduced before the rotor is activated. Can do.
According to this configuration, when the rotor is driven to rotate, first, the rotor is positioned at the rest position by the urging force generated by the magnetic circuit including the first yoke and the first coil, and then the rotor includes the second yoke and the second coil. In order to reduce the holding force generated by the magnetic circuit and then generate a rotational driving force in the magnetic circuit composed of the first yoke and the first coil, even if the rotor is slightly deviated from the rest position, the rotor is predetermined. It is possible to quickly start from the state of being positioned at the rest position.

The electromagnetic actuator having the above-described configuration includes a control unit that controls energization to the first coil and the second coil, and the control unit reduces the holding force with which the second yoke holds the rotor in the rest position. It is possible to employ a configuration in which after the energization control of the two coils, the first yoke energizes the first coil so as to start the rotor toward the maximum rotation position.
According to this configuration, when the rotor is rotationally driven, first, the holding force generated by the magnetic circuit composed of the second yoke and the second coil is reduced, and then the rotational circuit is driven by the magnetic circuit composed of the first yoke and the first coil. In order to generate a force, the rotor can be activated and rotated immediately and quickly in response to an activation command.

In the electromagnetic actuator having the above configuration, it is possible to adopt a configuration in which the first yoke and the second yoke are formed in different shapes.
According to this configuration, erroneous assembly can be prevented when the first yoke and the second yoke are assembled.

In the electromagnetic actuator having the above-described configuration, the first yoke is formed in a substantially U-shaped arm portion around which the first coil is wound, and both end regions of the arm portion are opposed to the outer peripheral surface of the rotor and is connected to the first coil. It has two magnetic pole portions that generate different magnetic poles when energized, and the second yoke is formed in a substantially U-shaped arm portion that winds the second coil, and both end regions of the arm portion, and is formed on the outer peripheral surface of the rotor. There are two magnetic pole portions that face each other and generate different magnetic poles when energized to the second coil. The magnetic pole portion of the first yoke and the magnetic pole portion of the second yoke are arranged so as to overlap in the rotation axis direction of the rotor. It is also possible to adopt a configuration.
According to this configuration, the first yoke and the second yoke are both formed in a substantially U shape, and the magnetic pole portions formed in the end regions thereof are in a region where the outer peripheral surfaces of the rotor overlap. Since the magnetic yoke is arranged so as to generate a magnetic attractive force and a repulsive force, the magnetic force generated by the first yoke (magnetic holding force by non-energization, the magnetic attractive force and repulsive force by energization) and the magnetic force generated by the second yoke (non-conductive) The magnetic holding force by energization, the magnetic attraction force and the repulsive force by energization, respectively can be sufficiently ensured (a predetermined level or more).

In the electromagnetic actuator having the above configuration, the first yoke and the second yoke adopt a configuration in which the arm portion wound with the first coil and the arm portion wound with the second coil are arranged on both sides of the rotor. can do.
According to this configuration, since the first yoke and the second yoke are arranged so as to be aligned in the radial direction of the rotor, the electromagnetic actuator can be thinned in the rotation axis direction of the rotor.

In the electromagnetic actuator configured as described above, the first yoke and the second yoke have the arm portion wound with the first coil and the arm portion wound with the second coil positioned at substantially the same height in the rotation axis direction of the rotor. Thus, it is possible to employ a configuration in which one of them is bent.
According to this configuration, the first yoke and the second yoke are arranged so as to be aligned in the radial direction of the rotor, and the arm portion of the first yoke and the arm portion of the second yoke are substantially the same height in the rotation axis direction of the rotor. Therefore, the heights of the first coil and the second coil wound around the respective arm portions can be lowered in the rotation axis direction of the rotor. Thereby, the electromagnetic actuator can be further reduced in thickness in the direction of the rotation axis of the rotor.

In the electromagnetic actuator having the above-described configuration, the first yoke and the second yoke are arranged such that the arm portion around which the first coil is wound and the arm portion around which the second coil is wound are overlapped in the rotation axis direction of the rotor. A configuration can be employed.
According to this configuration, by arranging the first yoke and the second yoke so as to overlap with each other, the parts can be concentrated in the vicinity of the rotor, and the area occupied by the electromagnetic actuator can be reduced in the plane direction perpendicular to the rotation axis of the rotor. Can be small.

A camera blade drive device according to the present invention comprises a substrate having an opening for exposure, a blade rotatably supported on the substrate to open / close the aperture or reduce the aperture to a predetermined aperture, and a blade. A drive source for driving, and any one of the electromagnetic actuators having the above-described configuration is employed as the drive source.
According to this configuration, since the above-described electromagnetic actuator is employed as a drive source, a sufficient holding force (detent torque) acts on the rotor while reducing the size of the apparatus. The blades to be performed can be surely positioned and held at a predetermined rest position (for example, the open position where the opening is fully opened), and when performing a shutter operation or a diaphragm operation, the rotor is quickly driven to obtain a desired The shutter operation or the aperture operation can be smoothly performed at the timing.

According to the electromagnetic actuator of the present invention having the above-described configuration, for example, when applied as a drive source for driving a shutter blade or a diaphragm blade of a camera while achieving reduction in size, weight, reduction of power consumption, etc. Even if an impact force is applied from the outside, these blades can be prevented from moving freely and held in place, and the desired shutter operation or aperture operation can be quickly performed during the original operation. An electromagnetic actuator capable of generating a driving force can be obtained.
In addition, according to the camera blade drive device of the present invention, since the electromagnetic actuator described above is employed as a drive source, the blade that performs the shutter operation or the aperture operation, etc., is reliably operated while the device is downsized. In this way, it can be reliably held at a desired rest position (for example, a fully open position or a non-throttle position).

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 8 show an embodiment in which an electromagnetic actuator according to the present invention is applied to a camera blade driving device (here, a camera shutter device). 1 and FIG. 2 are plan views of the device shown in solid lines for the structure of the blade chamber for convenience of explanation, FIG. 3 is a developed sectional view showing a part of the device, and FIG. 4 is an electromagnetic actuator mounted on the device. FIG. 5 is a plan view showing the first yoke, the first coil, and the rotor included in the electromagnetic actuator. FIG. 6 is a plan view showing the second yoke, the second coil, and the rotor included in the electromagnetic actuator. 7 is a time chart showing the drive control of the apparatus, and FIG. 8 is an operation diagram for explaining the operation of the electromagnetic actuator.

  As shown in FIGS. 1 to 3, the camera shutter device is rotated around the base plate 10 so as to open and close the base plate 10 and the back plate 20 and the openings 11 and 21 as substrates having openings 11 and 21 for exposure. A pair of shutter blades 31 and 32 as movably supported blades, an electromagnetic actuator 100 as a drive source for driving the shutter blades 31 and 32, and the like are provided.

As shown in FIGS. 1 to 3, the base plate 10 positions an opening 11 having a circular shape for exposure, a support shaft 12 that rotatably supports the rotor 110, a substantially fan-shaped through hole 13, and a first yoke 120. Positioning portion 14, positioning portion 15 for positioning the second yoke 140, support shafts 16 and 17, which respectively support the shutter blades 31 and 32 so as to be rotatable, a fully open stopper 18 for stopping the shutter blades 31 and 32 in a fully open position, A fully closed stopper 19 or the like for stopping the shutter blades 31 and 32 at the fully closed position is provided.
As shown in FIG. 3, the back plate 20 is formed to include a circular opening for exposure 21, a substantially fan-shaped through hole 22, fitting holes 23 and 24 for fitting the support shafts 16 and 17, and the like. The blade chamber W is connected to the rear side end surface of the base plate 10 with a screw or the like at a predetermined interval so as to demarcate the blade chamber W for rotatably accommodating the shutter blades 31 and 32.

  As shown in FIGS. 1 and 2, the shutter blades 31 and 32 have circular holes 31a and 32a into which the support shafts 16 and 17 are inserted, and long holes 31b into which drive pins 112 of the rotor 110 described later are inserted, respectively. 32b is formed. Then, as the rotor 110 rotates (the drive pin 112 reciprocates), the shutter blades 31 and 32 approach each other as shown in FIG. 2 and perform a closing operation to fully close the openings 11 and 21. On the other hand, as shown in FIG. 1, an opening operation is performed to fully open the openings 11 and 21 away from each other.

  As shown in FIGS. 1 to 4, the electromagnetic actuator 100 includes a rotor 110 that is rotatably supported by the base plate 10, a first yoke 120 that is fixed to the base plate 10, and a bobbin 130 a that is fitted to the first yoke 120. Formed by the first coil 130 for excitation wound around the second coil 140, the second yoke 140 fixed to the ground plane 10, the second coil 150 for excitation wound around the bobbin 150a fitted to the second yoke 140, and the like. Has been.

As shown in FIGS. 3 and 4, the rotor 110 is formed in a columnar shape, and is divided into two magnetic poles (N poles) divided by a through hole 111 a through which the support shaft 12 passes and a magnetic pole boundary surface passing through the rotation axis L. , S pole) and a rotor portion 111 that defines an N pole outer peripheral surface 111b and an S pole outer peripheral surface 111c, and a drive pin 112 that protrudes radially outward from the rotor portion 111 and further extends downward. .
The drive pin 112 transmits the rotational driving force of the rotor 110 to the outside, and is formed so as to be inserted into the long holes 31 b and 32 b of the shutter blades 31 and 32.

As shown in FIGS. 4 and 5, the first yoke 120 has a flat arm shape that is curved in a substantially U shape, and two magnetic pole portions that can generate different magnetic poles in both end regions. 122 and 123 are provided.
A bobbin 130 a around which the first coil 130 is wound is fitted to the arm portion 121.
The magnetic pole portion 122 is formed so as to delimit an arc surface 122a that faces the N pole outer peripheral surface 111b and the S pole outer peripheral surface 111c of the rotor 110.
The magnetic pole portion 123 is formed so as to delimit an arc surface 123a that faces the N pole outer peripheral surface 111b and the S pole outer peripheral surface 111c of the rotor 110.
The circular arc surfaces 122a and 123a are formed to have an inner diameter larger than the outer diameter of the rotor 110, and are opposed to the N pole outer peripheral surface 111b and the S pole outer peripheral surface 111c of the rotor 110 with a predetermined gap therebetween. Yes.

Further, when the first coil 120 is de-energized, the first yoke 120 is magnetically attracted between the magnetic pole portion 122 (arc surface 122a) and the S pole outer peripheral surface 111c, as shown in FIG. 5A. The magnetic pole portion 123 (arc surface 123a) exerts a magnetic attraction force between the magnetic pole portion 123 (arc surface 123a) and the N pole outer peripheral surface 111b, and urges the rotor 110 to rotate clockwise to drive the rest position θo (drive pin to the stopper So). When the first coil 130 is energized in one direction, as shown in FIG. 5B, the magnetic pole portion 122 (arc surface 122a) is formed. Exerts a magnetic attraction force with respect to the N pole outer peripheral surface 111b and the magnetic pole portion 123 (arc surface 123a) exerts a magnetic attraction force with respect to the S pole outer peripheral surface 111c, thereby rotating the rotor 110 counterclockwise. Rotation bias and maximum rotation position θm It is formed so as to generate a driving force that is rotationally driven toward ax (position where the driving pin 112 contacts the stopper Sm).
Furthermore, the first yoke 120 is formed to generate a holding force that holds the rotor 110 at the maximum rotational position θmax even when the first coil 130 is de-energized when the rotor 110 is positioned at the maximum rotational position θmax. .
The magnetic circuit composed of the first yoke 120 and the first coil 130 is mainly applied to generate a driving force for rotationally driving the rotor 110.

As shown in FIGS. 4 and 6, the second yoke 140 has a flat arm shape 141 that is curved in a substantially U shape, and two magnetic pole portions that can generate different magnetic poles in both end regions. 142, 143.
A bobbin 150 a around which the second coil 150 is wound is fitted to the arm portion 141.
The magnetic pole portion 142 is formed so as to delimit an arc surface 142a that faces the N-pole outer peripheral surface 111b and the S-pole outer peripheral surface 111c of the rotor 110.
The magnetic pole portion 143 is formed so as to delimit an arc surface 143a that faces the N pole outer peripheral surface 111b and the S pole outer peripheral surface 111c of the rotor 110.
The circular arc surfaces 142a and 143a are formed to have a circular arc surface larger than the outer diameter of the rotor 110, and are opposed to the N pole outer peripheral surface 111b and the S pole outer peripheral surface 111c of the rotor 110 with a predetermined gap. ing. Here, the inner diameters of the arc surfaces 142a and 143a may be the same as those of the arc surfaces 122a and 123a, but may be decreased or increased depending on the number of turns of the second coil 150 and the voltage value or current value when energized. May be.

Further, when the second coil 150 is deenergized, the second yoke 140 is magnetically attracted between the magnetic pole portion 142 (arc surface 142a) and the S pole outer peripheral surface 111c, as shown in FIG. The magnetic pole portion 143 (arc surface 143a) exerts a magnetic attraction force between the magnetic pole portion 143 (arc surface 143a) and the N pole outer peripheral surface 111b, and urges the rotor 110 to rotate clockwise to drive the rest position θo (drive pin to the stopper So). When the second coil 150 is energized in one direction, as shown in FIG. 6B, the magnetic pole part 142 (arc surface 142a) is formed. Exerts a magnetic attraction force with respect to the N pole outer peripheral surface 111b, and the magnetic pole portion 143 (arc surface 143a) exerts a magnetic attraction force with respect to the S pole outer peripheral surface 111c to reduce the holding force. Is formed.
Further, the second yoke 140 is formed so as to generate a holding force for holding the rotor 110 at the maximum rotational position θmax even when the second coil 150 is de-energized when the rotor 110 is positioned at the maximum rotational position θmax. However, the magnetic circuit including the second yoke 140 and the second coil 150 is mainly applied to generate a holding force that holds the rotor 110 at the rest position θo.

Here, the first yoke 120 and the second yoke 140 can also be formed in different shapes from each other, and prevent erroneous assembly when the first yoke 120 and the second yoke 140 are assembled to the ground plane 10. be able to.
As shown in FIGS. 3 and 4, the first yoke 120 and the second yoke 140 include two magnetic pole portions 122 and 123 of the first yoke 120 and two magnetic pole portions 142 and 143 of the second yoke 140. The rotor 110 is disposed so as to overlap in the rotation axis direction L (with a predetermined gap so as not to contact), and the arm portion 121 of the first yoke 120 and the arm portion 141 of the second yoke 140 It is arranged so as to be sandwiched from both sides (to face each other).

That is, the first yoke 120 and the second yoke 140 are both formed in a substantially U shape, and the magnetic pole portions 122 and 123 and the magnetic pole portions 142 and 143 formed in the end regions thereof are the outer periphery of the rotor 110. Since it is arranged so as to generate a magnetic attractive force and a repulsive force with respect to the region where the surfaces 111b and 111c overlap, the magnetic force generated by the first yoke 120 (the magnetic holding force due to de-energization, the magnetic attractive force and repulsive force due to current supply) Force) and the magnetic force generated by the second yoke 140 (magnetic holding force by non-energization, magnetic attraction and repulsive force by energization) can be sufficiently ensured (above a predetermined level).
Further, the first yoke 120 and the second yoke 140 are arranged on both sides of the rotor 110 with the arm portion 121 wound with the first coil 130 and the arm portion 141 wound with the second coil 150 interposed therebetween. The first yoke 120 and the second yoke 140 are arranged so as to be aligned in the radial direction of the rotor 110, and the electromagnetic actuator can be thinned in the rotation axis direction L of the rotor 110.

As described above, one magnetic circuit (the first yoke 120 and the first coil 130) is used for driving the rotor 110, and the other magnetic circuit (the second yoke 140 and the second coil 150) is used for holding the rotor 110. With this arrangement, when the rotor 110 is stopped at the rest position θo, a strong holding force (detent torque) can be obtained with the first coil 130 and the second coil 150 being de-energized. When starting toward the maximum rotational position θmax, the rotational driving force for starting from the rest position can be obtained by energizing the first coil 130 in one direction, and further, the second coil 150 can be energized in one direction. Therefore, the holding force can be weakened, and therefore the rotor 110 can be rotated quickly.
Therefore, the rotor 110 can be prevented from rotating freely from the rest position θo due to an impact or the like, and when the rotor 110 is started, the rotating operation can be smoothly performed. In addition, since less power is consumed by energizing the second coil 150 in order to reduce the holding force, the power consumption can be reduced compared to the case where both coils are energized for driving as in the prior art. Can do.

Next, the operation of the camera shutter device including the electromagnetic actuator 100 having the above-described configuration will be described with reference to FIGS. The overall drive control of the apparatus and the energization control of the first coil 130 and the second coil 150 are controlled by a control means (control unit) mounted on the apparatus.
Here, when energization control is performed on the first coil 130 and the second coil 150, energization is performed in such a direction that the shutter blades 31 and 32 open the openings 11 and 21 (so that the rotor 110 is rotated clockwise). Is “open energization”, and the case where energization is performed in such a direction that the shutter blades 31 and 32 close the openings 11 and 21 (so that the rotor 110 is rotated counterclockwise) is referred to as “closed energization”.

First, in a state where the first coil 130 and the second coil 150 are not energized (point A in FIG. 7), as shown in FIG. 1, the shutter blades 31 and 32 have the openings 11 and 21 fully opened. The rotor 110 is stopped at the rest position θo.
At this time, as shown in FIG. 8A, the magnetic pole portions 122 and 142 generate a magnetic attractive force with the S pole outer peripheral surface 111c, and the magnetic pole portions 123 and 143 have an N pole outer peripheral surface 111b. A magnetic attraction force is generated between the rotor 110 and the rotor 110, and the rotor 110 stops at a rest position θo that is a clockwise rotation end, and is held by a strong holding force (detent torque).

  Here, when the shutter blades 31 and 32 are closed (shutter operation), first, the first coil 130 is opened and energized (point B in FIG. 7). Then, as shown in FIG. 8B, the first yoke 120 has an N pole at the magnetic pole portion 122 and an S pole at the magnetic pole portion 123, respectively, and the rotor 110 is larger toward the rest position θo. It is urged to rotate clockwise by the urging force and is reliably positioned at the rest position θo.

  Subsequently, the second coil 150 is subjected to a closed energization (point C in FIG. 7) at a predetermined level (current or voltage smaller than the energization of the first coil 130). Then, as shown in FIG. 8C, the second yoke 140 has an S pole at the magnetic pole portion 142 and an N pole at the magnetic pole portion 143, respectively, and urges the rotor 110 toward the rest position θo. Holding power is reduced.

  Subsequently, the first coil 130 is closed and energized (point D in FIG. 7). Then, as shown in FIG. 8D, the first yoke 120 has an S pole at the magnetic pole portion 122 and an N pole at the magnetic pole portion 123, respectively, and the rotor 110 rotates toward the maximum rotational position θmax. Begin to. At this time, since the holding force by the second yoke 140 is already weakened, the rotor 110 can be started smoothly and quickly. As a result, the rotor 110 moves to the maximum rotational position θmax as shown in FIG. 8E, and the shutter blades 31 and 32 move to the fully closed position as shown in FIG. 11 and 21 are closed.

Then, after the shutter blades 31 and 32 fully close the openings 11 and 21, the second coil 150 is deenergized (point E in FIG. 7). As a result, in the second yoke 140, as shown in FIG. 8E, the S pole and the N pole generated by the electromagnetic force in the magnetic pole portions 142 and 143 disappear, and normal static magnetic attraction is achieved. The holding force that biases the rotor 110 to the maximum rotational position θmax is generated by the force.
Thereafter, the first coil 130 is further deenergized (point F in FIG. 7). Then, in the first yoke 120, as shown in (F) in FIG. 8, the S pole and N pole generated by the electromagnetic force in the magnetic pole portions 122 and 123 disappear, and a normal static magnetic attractive force is obtained. Thus, a holding force that biases the rotor 110 to the maximum rotational position θmax is generated. The E point and the F point may be the same point, and the first coil 130 and the second coil 150 may be de-energized at the same time.
Thus, both the magnetic circuit formed by the first yoke 120 and the first coil 130 and the magnetic circuit formed by the second yoke 140 and the second coil 150 cause the rotor 110 to move to the maximum rotational position θmax in a non-energized state. Therefore, the power consumption can be reduced as compared with the case where the maximum rotational position θmax is held by energization (single-side suction).

  Then, after the fully closed state is maintained for a predetermined time, the first coil 120 and the second coil 150 are energized in the other direction (point G in FIG. 7). Then, as shown in FIG. 8G, the first yoke 120 has an N pole at the magnetic pole portion 122 and an S pole at the magnetic pole portion 123, respectively, and the magnetic pole portion 142 at the second yoke 140. The N pole and the S pole are generated in the magnetic pole portion 143, and the rotor 110 starts to rotate toward the rest position θo. Then, as shown in FIG. 1, the shutter blades 31 and 32 return to the fully open position that is the original rest position. Further, the point G may be divided into two points, and the first coil 130 may be energized after the second coil 150 is energized.

As described above, the control means controls the energization of the first coil 130 so as to start the rotor 110 toward the maximum rotation position θmax after the first yoke 120 urges the rotor 110 to rotate toward the rest position θo, and the rotor 110. Before the second coil 140 is activated, the second coil 150 is energized and controlled so as to reduce the holding force for the second yoke 140 to hold the rotor 110 at the rest position θo.
That is, when the rotor 110 is rotationally driven, first, the rotor 110 is positioned at the rest position θo by the urging force generated by the magnetic circuit including the first yoke 120 and the first coil 130, and then the second yoke 140 and the second coil. In order to reduce the holding force generated by the magnetic circuit composed of 150 and then generate a rotational driving force in the magnetic circuit composed of the first yoke 120 and the first coil 130, the rotor 110 is slightly shifted from the rest position θo. Even in such a case, the rotor 110 is quickly started from a state where the rotor 110 is positioned at the predetermined rest position θo.

As described above, one magnetic circuit (the first yoke 120 and the first coil 130) is used for driving the rotor 110, and the other magnetic circuit (the second yoke 140 and the second coil 150) is used for holding the rotor 110. When the rotor 110 is stopped at the rest position θo, a strong holding force (detent torque) can be obtained in a state where the first coil 130 and the second coil 150 are not energized. Is activated toward the maximum rotation position θmax, the first coil 130 is energized in one direction to obtain a rotational driving force for activation from the rest position, and further, the second coil 150 is energized in one direction. Thus, the holding force can be reduced and the rotor 110 can be quickly rotated.
Therefore, the rotor 110 can be prevented from rotating freely from the rest position θo due to an impact or the like, and when the rotor 110 is started, the rotating operation can be smoothly performed. In addition, since less power is consumed by energizing the second coil 150 in order to reduce the holding force, the power consumption can be reduced compared to the case where both coils are energized for driving as in the prior art. Can do.

  9 and 10 show another embodiment of drive control of the camera shutter device provided with the electromagnetic actuator 100. FIG. Note that the overall drive control of the apparatus and the energization control of the first coil 130 and the second coil 150 are controlled by the control means (control unit) mounted on the apparatus, as described above.

  That is, in this embodiment, first, in a state where the first coil 130 and the second coil 150 are not energized (point A in FIG. 9), as shown in FIG. 11 and 21 are fully opened, and the rotor 110 is stopped at the rest position θo. At this time, as shown in FIG. 10A, the magnetic pole portions 122 and 142 generate a magnetic attractive force with the S pole outer peripheral surface 111c, and the magnetic pole portions 123 and 143 have an N pole outer peripheral surface 111b. A magnetic attraction force is generated between the rotor 110 and the rotor 110, and the rotor 110 stops at a rest position θo that is a clockwise rotation end, and is held by a strong holding force (detent torque).

  Here, when the shutter blades 31 and 32 perform the closing operation (shutter operation), first, the second coil 150 is closed and energized at a predetermined level (current or voltage smaller than the closing energization of the first coil 130) (FIG. 9). (B point in the middle). Then, as shown in FIG. 10B, the second yoke 140 has an S pole at the magnetic pole portion 142 and an N pole at the magnetic pole portion 143, respectively, and urges the rotor 110 toward the rest position θo. Holding power is reduced.

Subsequently, the first coil 130 is closed and energized (point C in FIG. 9). Then, as shown in FIG. 10C, the first yoke 120 has an S pole at the magnetic pole portion 122 and an N pole at the magnetic pole portion 123, and the rotor 110 rotates toward the maximum rotation position θmax. Begin to. At this time, since the holding force by the second yoke 140 is already weakened, the rotor 110 can be started smoothly and quickly.
As a result, the rotor 110 moves to the maximum rotational position θmax as shown in FIG. 10D, and the shutter blades 31 and 32 move to the fully closed position as shown in FIG. 11 and 21 are closed.

Then, after the shutter blades 31 and 32 fully close the openings 11 and 21, the second coil 150 is deenergized (point D in FIG. 9). As a result, in the second yoke 140, as shown in FIG. 10D, the S and N poles generated by the electromagnetic force in the magnetic pole portions 142 and 143 disappear, and normal static magnetic attraction is achieved. The holding force that biases the rotor 110 to the maximum rotational position θmax is generated by the force.
Thereafter, the first coil 130 is further deenergized (point E in FIG. 9). Then, in the first yoke 120, as shown at (E) in FIG. 10, the S pole and the N pole generated by the electromagnetic force in the magnetic pole portions 122 and 123 disappear, and a normal static magnetic attractive force is obtained. Thus, a holding force that biases the rotor 110 to the maximum rotational position θmax is generated. Note that the point D and the point E in FIG. 9 may be the same point, and the first coil 130 and the second coil 150 may be de-energized simultaneously.

  Thus, both the magnetic circuit formed by the first yoke 120 and the first coil 130 and the magnetic circuit formed by the second yoke 140 and the second coil 150 cause the rotor 110 to move to the maximum rotational position θmax in a non-energized state. Therefore, the power consumption can be reduced as compared with the case where the maximum rotational position θmax is held by energization (single-side suction).

  Then, after the fully closed state is maintained for a predetermined time, the first coil 130 and the second coil 150 are energized in the other direction (point F in FIG. 9). Then, as shown in FIG. 10F, the first yoke 120 has an N pole at the magnetic pole portion 122 and an S pole at the magnetic pole portion 123, respectively, and the magnetic pole portion 142 at the second yoke 140. The N pole and the S pole are generated in the magnetic pole portion 143, and the rotor 110 starts to rotate toward the rest position θo. Then, as shown in FIG. 1, the shutter blades 31 and 32 return to the fully open position that is the original rest position. Further, the point G may be divided into two points, and the first coil 130 may be energized after the second coil 150 is energized.

As described above, the control means controls the energization of the second coil 150 so that the second yoke 140 reduces the holding force for holding the rotor 110 at the rest position θo, and then the first yoke 120 rotates the rotor 110 to the maximum. The first coil 130 is energized to be activated toward the position θmax.
That is, when the rotor 110 is rotationally driven, first, the holding force generated by the magnetic circuit composed of the second yoke 140 and the second coil 150 is reduced, and then the magnetic circuit composed of the first yoke 120 and the first coil 130 is rotated. In order to generate a driving force, the rotor 110 can be started immediately and quickly in response to a start command.

FIG. 11 shows another embodiment of the electromagnetic actuator according to the present invention. The same components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.
That is, in this embodiment, the electromagnetic actuator 100 is formed by a rotor 110, a first yoke 120 ′, a first coil 130, a second yoke 140, a second coil 150, etc., as shown in FIG.

The first yoke 120 ′ is formed by bending an arm portion 121 ′ around which the first coil 130 is wound, and the arm portion 121 ′ around which the first coil 130 is wound and the second coil 150 are wound around. The arm portions 141 are formed so as to be positioned at substantially the same height in the rotation axis direction L of the rotor 110.
Therefore, the heights of the first coil 130 and the second coil 150 wound around the respective arm portions 121 ′ and 141 of the first yoke 120 ′ and the second yoke 140 are lowered in the rotation axis direction L of the rotor 110. be able to. Thereby, the electromagnetic actuator 100 can be further reduced in thickness in the rotation axis direction L of the rotor 110.
In FIG. 11, the bent portion is provided in the first yoke 120 ′, but the bent portion may be provided in the second yoke.

FIG. 12 shows still another embodiment of the electromagnetic actuator according to the present invention. The same components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.
That is, in this embodiment, as shown in FIG. 12, the electromagnetic actuator 100 is formed by a rotor 110 ″, a first yoke 120 ″, a first coil 130, a second yoke 140 ″, a second coil 150, and the like. Has been.
As shown in FIG. 12, the rotor 110 ″ has a rotor portion 111 ″ that is longer in the rotation axis direction L than the rotor portion 111 described above.
In the first yoke 120 ″ and the second yoke 140 ″, the arm part 121 wound with the first coil 130 and the arm part 141 wound with the second coil 150 overlap in the rotation axis direction L of the rotor 110. (With a predetermined gap).
In this manner, by arranging the first yoke 120 ″ and the second yoke 140 ″ so as to overlap with each other, the components can be concentrated in the vicinity of the rotor 110 ″, and the rotation axis L of the rotor 110 ″ can be integrated. The occupation area of the electromagnetic actuator 100 can be reduced in the vertical plane direction.

  In the above embodiment, a camera shutter device having shutter blades 31 and 32 applied to a digital camera, a silver salt film camera, or the like as a camera blade drive device employing the electromagnetic actuator 100 according to the present invention as a drive source. However, the present invention is not limited to this, and the present invention is applied to a digital camera, a silver salt film camera, etc., and is used as a drive source for driving aperture blades that narrow the apertures 11 and 21 for exposure to a predetermined aperture. A diaphragm device for a camera that employs the electromagnetic actuator 100 according to the invention may be used.

  As described above, the electromagnetic actuator of the present invention can achieve a desired rotational driving force while achieving a reduction in size and weight, and a particularly strong magnetic holding force (detent torque). Since the rotor can be stably held at a predetermined rest position against impact force from the motor, it can be applied as a normal drive source, in particular, a mobile phone, a portable personal computer, etc. It is useful as a drive source for shutter blades or diaphragm blades of devices mounted on portable information terminals or digital cameras.

4 is a plan view showing a structure of a blade chamber side for convenience of a camera shutter device provided with an electromagnetic actuator according to the present invention by a solid line. FIG. 4 is a plan view showing a structure of a blade chamber side for convenience of a camera shutter device provided with an electromagnetic actuator according to the present invention by a solid line. FIG. FIG. 3 is a developed sectional view showing a part of the camera shutter device shown in FIGS. 1 and 2. It is a top view which shows one Embodiment of the electromagnetic actuator which concerns on this invention. 4A and 4B show a first yoke and a first coil and a rotor that form a part of the electromagnetic actuator shown in FIG. 4, wherein FIG. 4A is a plan view in which the rotor is stopped at a rest position, and FIG. It is the top view which stopped. FIG. 5 shows the second yoke and the second coil and the rotor forming part of the electromagnetic actuator shown in FIG. 4, (a) is a plan view in which the rotor is stopped at the rest position, and (b) is the rotor at the maximum rotation position. It is the top view which stopped. It is a time chart which shows drive control of the shutter apparatus for cameras (and electromagnetic actuator). FIG. 8 is an operation diagram illustrating states of the rotor, the first yoke, and the second yoke that are driven based on the time chart illustrated in FIG. 7. It is a time chart which shows the other drive control of the shutter apparatus for cameras (and electromagnetic actuator). FIG. 10 is an operation diagram illustrating states of the rotor, the first yoke, and the second yoke that are driven based on the time chart illustrated in FIG. 9. It is a developed sectional view showing other embodiments of a camera shutter device and an electromagnetic actuator concerning the present invention. FIG. 6 is a developed cross-sectional view showing still another embodiment of the camera shutter device and electromagnetic actuator according to the present invention.

Explanation of symbols

10 Ground plane (substrate)
20 Back plate (substrate)
11, 21 Opening for exposure 12 Support shaft 13 Through holes 14, 15 Positioning portions 16, 17 Support shaft 18 Fully open stopper 19 Fully closed stopper 22 Through hole 23 Fitting hole 24 Fitting holes 31, 32 Shutter blade 31a Circular hole 31b Long hole 32a Circular hole 32b Long hole 100 Electromagnetic actuator (drive source)
110, 110 ″ Rotor 111, 111 ″ Rotor portion 111a Through hole 111b N pole outer peripheral surface 111c S pole outer peripheral surface 112 Drive pins 120, 120 ′, 120 ″ First yoke 121, 121 ′ Arm portions 122, 123 2 Two magnetic pole portions 122a, 123a Arc surface 130 First coil 130a Bobbin 140, 140 ″ Second yoke 141 Arm portions 142, 143 Two magnetic pole portions 142a, 143a Arc surface 150 Second coil 150a Bobbin θo Rest position θmax Maximum rotation position L Rotor axis direction So Stopper Sm Stopper W Blade chamber

Claims (10)

Magnetic attraction and repulsive force can be generated between the rotor having an outer peripheral surface magnetized in the N pole and the S pole and rotating in the angular range between the rest position and the maximum rotational position, and the outer peripheral surface of the rotor. A first yoke, a first coil for excitation wound around the first yoke, a second yoke capable of generating a magnetic attractive force and a repulsive force between the outer peripheral surface of the rotor, and the second yoke An electromagnetic actuator comprising a second coil for excitation wound around
The first yoke generates a holding force for holding the rotor in a rest position when the first coil is de-energized, and directs the rotor to a maximum rotation position when the first coil is energized in one direction. Formed to generate a driving force for rotational driving,
The second yoke generates a holding force for holding the rotor in a rest position when the second coil is de-energized, and reduces the holding force when the second coil is energized in one direction. Formed,
An electromagnetic actuator characterized by that. The first yoke is formed to generate a holding force that holds the rotor in a maximum rotation position when the first coil is de-energized,
The second yoke is formed to generate a holding force that holds the rotor in a maximum rotation position when the second coil is de-energized.
The electromagnetic actuator according to claim 1. Control means for controlling energization to the first coil and the second coil;
The control means controls the energization of the first coil to activate the rotor toward the maximum rotation position after the first yoke urges the rotor to rotate to the rest position, and before starting the rotor, The second yoke controls the energization of the second coil so as to reduce the holding force for holding the rotor in the rest position;
The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is characterized in that Control means for controlling energization to the first coil and the second coil;
The control means controls the energization of the second coil so that the holding force of the second yoke holding the rotor in the rest position is reduced, and then the first yoke starts the rotor toward the maximum rotation position. Energization control of the first coil in order to
The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is characterized in that The first yoke and the second yoke are formed in different shapes,
The electromagnetic actuator according to any one of claims 1 to 4, wherein the electromagnetic actuator is provided. The first yoke is formed in a substantially U-shaped arm portion that winds the first coil, and is formed in both end regions of the arm portion so as to face the outer peripheral surface of the rotor, and by energizing the first coil. Having two magnetic pole portions that produce different magnetic poles;
The second yoke is formed in a substantially U-shaped arm portion around which the second coil is wound, and both end regions of the arm portion so as to face the outer peripheral surface of the rotor, and by energizing the second coil. Having two magnetic pole portions that produce different magnetic poles;
The magnetic pole part of the first yoke and the magnetic pole part of the second yoke are arranged so as to overlap in the rotation axis direction of the rotor,
An electromagnetic actuator according to any one of claims 1 to 5, wherein In the first yoke and the second yoke, an arm portion around which the first coil is wound and an arm portion around which the second coil is wound are arranged on both sides of the rotor.
The electromagnetic actuator according to claim 6. The first yoke and the second yoke are arranged such that the arm portion around which the first coil is wound and the arm portion around which the second coil is wound are positioned at substantially the same height in the rotation axis direction of the rotor. One of them is bent,
The electromagnetic actuator according to claim 7. The first yoke and the second yoke are arranged so that an arm portion around which the first coil is wound and an arm portion around which the second coil is wound are overlapped with each other in the rotation axis direction of the rotor.
The electromagnetic actuator according to claim 6. A substrate having an opening for exposure; a blade rotatably supported on the substrate to open / close or narrow the opening to a predetermined aperture to adjust the amount of light; and a drive source for driving the blade. ,
The drive source is the electromagnetic actuator according to any one of claims 1 to 8,
A blade drive device for a camera.

Images