JP2009069733A - Electromagnetic actuator and blade drive device for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase speeding of an electromagnetic actuator for driving a shutter blade or the like of a camera and improve shock resistance when not in operation. <P>SOLUTION: The electromagnetic actuator is equipped with a rotor 110 generating driving force by turning in a predetermined angle range, an exciting coil 140, and a yoke 120 having a first magnetic pole part 121 and a second magnetic pole part 122 respectively demarcating arc-shaped surfaces facing the outer peripheral surface of the rotor and generating magnetic poles different from each other by energizing the coil. The arc-shaped surfaces 121a and 122a of the fist and second magnetic pole parts 121 and 122 are formed so that the distances to the outer peripheral surfaces 111b and 111c from the rotor may be continuously changed (increased from one end side to the other end side of the arc-shaped surface) in the rotating direction of the rotor. Thus, the rotor is smoothly rotated more quickly in one direction, whereby the shutter blade is closed (shutter operation) at higher speed, and shock resistance during non-energization is improved by changing the magnetization direction and the energizing method 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 in particular, includes a magnetized columnar rotor, a yoke that forms a magnetic pole portion facing the outer peripheral surface of the rotor, and the like, and includes shutter blades and a diaphragm of a camera. The present invention relates to an electromagnetic actuator applied when driving a blade such as a blade and a blade driving device for a camera using the electromagnetic actuator.

  As a conventional electromagnetic actuator mounted on a shutter device for a camera, etc., it is supported so as to be rotatable with respect to a substrate having a circular opening, and the outer peripheral surface is divided into two in the circumferential direction (N pole and S pole). ) Columnar rotor, a substantially U-shaped yoke having a pole piece defining an arcuate surface facing the outer peripheral surface of the rotor, an excitation coil wound around the yoke, etc. In order to increase the holding force (detent torque), the pole piece facing the rotor is divided into a large divided pole piece forming a long arc and a small divided pole piece forming a short arc ( For example, see Patent Document 1).

  As other electromagnetic actuators, similarly to the above, a cylindrical rotor whose outer peripheral surface is divided in the circumferential direction and magnetized (N pole and S pole), and an arc surface facing the outer peripheral surface of the rotor are defined. A substantially U-shaped yoke having a magnetic pole part, an exciting coil wound around the yoke, etc., and provided with a protruding part protruding radially from the outer peripheral surface of the rotor in order to increase the driving torque Is known (see, for example, Patent Document 2).

  However, in the electromagnetic actuator described in Patent Document 1, the magnetic pole piece is bent so as to face the outer peripheral surface of the rotor, and is formed into two magnetic pole pieces (a large divided magnetic pole piece and a small divided magnetic pole piece) divided in the circumferential direction. Therefore, the structure is complicated and the manufacturing cost is increased. In addition, the case where the interval (magnetic gap) where the large divided magnetic pole pieces oppose to the outer peripheral surface of the rotor is different from the interval (magnetic gap) where the small divided magnetic pole pieces oppose is shown, but the interval is discontinuous. In addition, the rotation of the rotor may not be performed smoothly because it is not set quantitatively. In the electromagnetic actuator described in Patent Document 2, the arc surface of the magnetic pole part is formed so as to form a constant interval (magnetic gap) with respect to the outer peripheral surface of the rotor, but the structure is simple. Providing protrusions on the rotor increases the inertial mass of the rotor, and if the response is maintained as before, the power consumption increases. On the other hand, maintaining the power consumption as before causes the response to deteriorate. become.

JP 2001-327143 A JP 2004-194403 A

  The present invention has been made in view of the above circumstances, and its object is to drive the rotor when it rotates in one direction while simplifying the structure, reducing the size, reducing the cost, and the like. An electromagnetic actuator that can drive the blade smoothly and at a higher speed when it is used as a drive source for driving a blade such as a shutter blade or a diaphragm blade of a camera by increasing torque, rotational speed, responsiveness, etc. And providing a blade driving device for a camera using the same.

The electromagnetic actuator of the present invention defines a rotor having a cylindrical outer peripheral surface magnetized by being divided into two in the circumferential direction, an exciting coil, and an arcuate surface facing the outer peripheral surface of the rotor, respectively. An electromagnetic actuator comprising a yoke having a first magnetic pole part and a second magnetic pole part that generate different magnetic poles when energized, and that generates a driving force by rotating a predetermined angular range, the first magnetic pole part and The arc-shaped surface of the second magnetic pole part is formed so as to continuously change the distance from the outer peripheral surface of the rotor in the rotation direction of the rotor.
According to this configuration, since the interval continuously changes (that is, the interval continuously increases or decreases from one end side to the other end side of the arcuate surface in the rotation direction (circumferential direction) of the rotor, The rotor can be smoothly rotated, and the speed when rotating the rotor in one direction can be made higher than the speed when rotating in the other direction. Therefore, when it is desired to drive a predetermined driven body quickly only in one direction, the driven body can be operated smoothly and quickly by using this electromagnetic actuator. Further, since only the interval between the rotor and the first magnetic pole part and the second magnetic pole part is changed, the structure can be simplified, reduced in size, reduced in cost, etc. as compared with the conventional electromagnetic actuator.

In the electromagnetic actuator having the above configuration, when the minimum value of the interval is X and the maximum value is Y, the following conditional expression X <Y <2X
A configuration that satisfies the above can be adopted.
According to this configuration, the holding force of the rotor due to the detent torque is achieved by forming the distance between the rotor (the outer peripheral surface thereof) and the first magnetic pole portion and the second magnetic pole portion (the arc-shaped surface thereof) so as to satisfy the conditional expression. The rotational speed in one direction of the rotor can be increased while ensuring.

In the electromagnetic actuator having the above configuration, the outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole portion and the second magnetic pole portion are formed so as to hold the rotor at both end positions in the angular range, respectively, while the coil is not energized. The configuration can be adopted.
According to this configuration, since the rotor is held at both end positions in a non-energized state, power consumption can be reduced.

In the electromagnetic actuator having the above-described configuration, the outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole portion and the second magnetic pole portion are formed so as to hold the rotor only at one end position in the angle range while the coil is not energized. The configuration can be adopted.
According to this configuration, since the rotor is held only at one end position in a non-energized state, the reciprocating rotation of the rotor can be controlled by simple energization control with only one-way energization on / off.

Further, the camera blade driving device of the present invention is configured to perform a substrate having an opening, an opening operation for moving the opening to a fully opened position, and a closing operation for moving the opening to a fully closed position. A blade driving device for a camera comprising a blade supported rotatably on the blade and a drive source for driving the blade, wherein the drive source is a cylindrical outer peripheral surface magnetized in half in the circumferential direction. And a rotor for driving the blades to open and close, an exciting coil, an arcuate surface facing the outer peripheral surface of the rotor, and a first magnetic pole portion and a second magnetic pole portion that generate different magnetic poles by energizing the coil. Including a yoke having a magnetic pole portion, and the arc-shaped surfaces of the first magnetic pole portion and the second magnetic pole portion are formed so as to continuously change the distance from the outer peripheral surface of the rotor in the rotation direction of the rotor. Features
According to this configuration, since the interval continuously changes (that is, the interval continuously increases or decreases from one end side to the other end side of the arcuate surface in the rotation direction (circumferential direction) of the rotor, The rotor can be smoothly rotated, and the speed when rotating the rotor in one direction can be made higher than the speed when rotating in the other direction. Therefore, when it is desired to drive the blade quickly in only one direction, the blade can be operated smoothly and quickly by using this electromagnetic actuator. Further, since only the distance between the rotor and the first magnetic pole part and the second magnetic pole part is changed, the structure can be simplified, downsized, and the cost can be reduced as compared with the conventional drive source.

In the camera blade driving device having the above configuration, when the minimum value of the interval is X and the maximum value is Y, the following conditional expression X <Y <2X
A configuration that satisfies the above can be adopted.
According to this configuration, the holding force of the rotor due to the detent torque is achieved by forming the distance between the rotor (the outer peripheral surface thereof) and the first magnetic pole portion and the second magnetic pole portion (the arc-shaped surface thereof) so as to satisfy the conditional expression. While ensuring, the rotational speed in one direction of the rotor, that is, the operation in one direction of the blades can be increased.

In the camera blade driving device having the above configuration, the interval is formed such that the magnetic attractive force generated when the blade is in the fully closed position is larger than the magnetic attractive force generated when the blade is in the fully open position. A configuration can be employed.
According to this configuration, since the operation of closing the opening by moving the blade from the fully open position to the fully closed position is performed quickly, a smooth and high-speed shutter operation is performed when the blade functions as a shutter blade. be able to.

In the blade driving device for a camera having the above-described configuration, the outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole portion and the second magnetic pole portion are configured to hold the blade at the fully open position and the fully closed position, respectively, while the coil is not energized. It is possible to adopt the configuration formed in the above.
According to this configuration, since the blade is held in the fully open position and the fully closed position while the coil is not energized, power consumption can be reduced.

In the camera blade driving device having the above-described configuration, the outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole portion and the second magnetic pole portion are formed so as to hold the blade only at the fully open position while the coil is not energized. The configuration can be adopted.
According to this configuration, since the coil is not energized and the blade is held only in the fully open position, the opening / closing operation of the blade can be performed by simple energization control to turn on / off the energization in the direction in which the closing operation is performed. Can be controlled.

  According to the electromagnetic actuator and the camera blade drive device of the present invention having the above-described configuration, the rotor (and the blade) rotates (operates) in one direction while achieving simplification of structure, size reduction, cost reduction, and the like. Driving torque, rotational speed, responsiveness, etc. can be increased, and the shutter blades, diaphragm blades, etc. of the camera can be operated smoothly and faster.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 9 show an embodiment of a camera blade driving device provided with an electromagnetic actuator according to the present invention as a driving source. 1 and FIG. 2 are plan views of the inside of the apparatus seen through, FIG. 3 is a partial cross-sectional view of the apparatus, FIG. 4 is a plan view showing the electromagnetic actuator, FIG. 5 is a partial view of the electromagnetic actuator, FIG. Is a diagram showing the relationship between the spacing between the rotor and the first magnetic pole part and the second magnetic pole part, the holding force and the speed, FIGS. 7 and 8 are operation diagrams of the electromagnetic actuator, and FIG. 9 is a time chart when performing energization control. is there.

  As shown in FIGS. 1 to 3, this apparatus is rotatably supported on the base plate 10 so as to open and close the base plate 10 and the back plate 20 and the openings 10a, 20a as substrates having circular openings 10a, 20a. The shutter blade 30 is a blade, and the electromagnetic actuator 100 is a drive source for driving the shutter blade 30.

As shown in FIGS. 1 to 3, the base plate 10 includes an opening 10a, a support shaft 11 that rotatably supports a rotor 110 described later, a substantially fan-shaped through hole 10b, a pin 12 that positions a yoke 120 described later, and A projection 13, a connecting portion 14 that connects a presser plate 150 described later, and support shafts 15 a and 15 b that rotatably support the shutter blade 30 are provided.
As shown in FIG. 3, the back plate 20 is connected to the base plate 10 at a predetermined interval, and defines a blade chamber W in which the shutter blade 30 is rotatably accommodated.

As shown in FIGS. 1 and 2, the shutter blade 30 is formed by a pair of shutter blades 31 and 32. As shown in FIGS. 1 and 2, the shutter blade 31 includes a circular hole 31 a into which the support shaft 15 a is inserted and a long hole 31 b into which a drive pin 112 described later is inserted. As shown in FIGS. 1 and 2, the shutter blade 32 includes a circular hole 32 a into which the support shaft 15 b is inserted and a long hole 32 b into which a drive pin 112 described later is inserted.
Then, as the drive pin 112 reciprocates, the pair of shutter blades 31 and 32 move away from each other as shown in FIG. 1 and move to the fully opened position where the opening 10a is fully opened, and FIG. As shown in the figure, a closing operation is performed to move to a fully closed position where the openings 10a and 20a are fully closed by approaching each other.

  As shown in FIGS. 1 to 3, the electromagnetic actuator 100 includes a rotor 110 that is rotatably supported by the base plate 10, a substantially U-shaped yoke 120, a bobbin 130 that is externally fitted and fixed to the yoke 120, and a bobbin The exciting coil 140 wound around 130, the rotor 110 is prevented from falling off, and the yoke 120 is pressed into the base plate 10 and fixed thereto.

As shown in FIG. 3 and FIGS. 4A and 4B, the rotor 110 is integrally coupled to the magnet portion 111 formed in a columnar shape and the drive for transmitting the rotational driving force to the outside. A pin 112 is provided.
As shown in FIGS. 4 (a), 4 (b), and 5, the magnet unit 111 is divided into two magnetic poles separated by a boundary surface F passing through the through hole 111a through which the support shaft 11 passes and the rotation axis L. The outer peripheral surface 111b on the N pole side and the outer peripheral surface 111c on the S pole side that are magnetized are formed. The outer peripheral surfaces 111b and 111c define a cylindrical outer peripheral surface as a whole.
The rotor 110 rotates a predetermined angular range (operation angle) Δθ in which the position of the drive pin 112 is defined by one end position θ1 shown in FIG. 4A and the other end position θ2 shown in FIG. 4B. It comes to move.

  The yoke 120 forms a magnetic path that guides the generated lines of magnetic force, and is formed in a substantially U shape as shown in FIGS. 4A, 4B, and 5, and has a first magnetic pole in one end region thereof. The second magnetic pole portion 122 is formed in the other end region, and the positioning hole 123 through which the pin 12 is passed in the bent region.

As shown in FIG. 5, the first magnetic pole portion 121 is formed to be curved over an angular range of a predetermined center angle α1, and defines an arcuate surface 121a that faces the outer peripheral surfaces 111b and 111c of the rotor 110. ing.
As shown in FIG. 5, the arc-shaped surface 121 a is formed so as to face the outer peripheral surfaces 111 b and 111 c between the one end position P <b> 11 and the other end position P <b> 12 in the rotation direction (circumferential direction) of the rotor 110. It is formed to be curved so that the distance between the surfaces 111b and 111c is continuously changed, that is, continuously increased from one end position P11 to the other end position P12.

As shown in FIG. 5, the second magnetic pole portion 122 is formed to be curved over an angular range of a predetermined central angle α2, and defines an arcuate surface 122 a that faces the outer peripheral surfaces 111 b and 111 c of the rotor 110. ing.
As shown in FIG. 5, the arcuate surface 122a is formed so as to face the outer peripheral surfaces 111b and 111c between the one end position P21 and the other end position P22 in the rotation direction (circumferential direction) of the rotor 110. It is formed to be curved so that the distance between the surfaces 111b and 111c is continuously changed, that is, continuously increased from one end position P21 toward the other end position P22.

As described above, the arc-shaped surface 121a of the first magnetic pole part 121 and the arc-shaped surface 122a of the second magnetic pole part 122 continuously change the distance between the outer peripheral surfaces 111b and 111c of the rotor 110 in the rotation direction of the rotor 110. That is, the rotor 110 is smoothly rotated because the arc-shaped surfaces 121a and 122a are formed so as to continuously increase from one end side (P11, P21) to the other end side (P12, P22). In addition, the speed when rotating the rotor 110 in one direction (clockwise in FIG. 4) can be higher than the speed when rotating the rotor 110 in the other direction (counterclockwise in FIG. 4).
In other words, the interval is such that the magnetic attractive force generated when the shutter blade 30 is in the fully closed position shown in FIG. 2 is larger than the magnetic attractive force generated when the shutter blade 30 is in the fully open position shown in FIG. Is formed. Therefore, the closing operation in which the shutter blade 30 moves from the fully open position shown in FIG. 1 toward the fully closed position shown in FIG. 2 can be performed smoothly and at a higher speed.
Further, since the distance between the rotor 110 and the first magnetic pole part 121 and the second magnetic pole part 122 is changed, that is, only the shapes of the arcuate surfaces 121a and 122a are changed, the speed is increased compared with the conventional electromagnetic actuator. Therefore, it is possible to achieve simplification of the structure, size reduction, cost reduction, and the like.

Here, as shown in FIG. 5, the interval (minimum value) at one end positions P11, P21 of the arcuate surfaces 121a, 122a is X, and the interval (maximum value) at the other end positions P12, P22 of the arcuate surfaces 121a, 122a is Y. When the distance between the arcuate surfaces 121a and 122a and the outer peripheral surfaces 111b and 111c in the radial direction is preferably the following conditional expression X <Y <2X
It is formed so as to satisfy.

The conditional expression will be described with reference to FIG. FIG. 6 shows the rotation speed (shutter speed) of the rotor 110 and the holding force (magnetic attraction force) when the shutter blade 30 is in the fully open position when the maximum value Y of the distance is changed with respect to the minimum value X of the distance. ).
As shown in FIG. 6, when the maximum value Y is monotonously increased with reference to the minimum value X of the interval, the rotational speed (shutter speed) of the rotor 110 gradually increases, while the holding force (magnetic (Suction force) gradually decreases.
Therefore, the value of Y is set in the range of X to 2X, that is, the rotor 110 (the outer peripheral surfaces 111b and 111c), the first magnetic pole portion 121 (the arc-shaped surface 121a), and the second magnetic pole portion 122 (the arc-shaped surface 122a). ) Is set so that the minimum value is X and the maximum value is Y, so that the relationship of X <Y <2X is satisfied, so that the holding force of the rotor 110 by the detent torque (magnetic attraction force) is increased. While ensuring, the rotational speed of the rotor 110 in one direction (clockwise), that is, the speed at which the shutter blade 30 performs the closing operation can be increased.

As shown in FIGS. 3 and 4A and 4B, the bobbin 130 is fitted and fixed to the yoke 120 through the second magnetic pole portion 122 side of the yoke 120.
The coil 140 is wound around the bobbin 130. Then, when the coil 140 is energized in one direction, a magnetic line of force that exerts a magnetic urging force (attraction force and repulsive force) that rotates the rotor 110 clockwise is generated, and when the coil 140 is energized in the opposite direction, Magnetic field lines are generated that exert a magnetic urging force (attraction force and repulsive force) that rotates the rotor 110 counterclockwise.
As shown in FIG. 3, the presser plate 150 is formed in a flat plate shape, restricts falling off of the rotor 110 that is rotatably supported by the support shaft 11 of the base plate 10, and the yoke 120 to which the bobbin 130 is attached. Is pressed against the main plate 10 to be fixed.

The operation of the camera blade drive device including the electromagnetic actuator 100 having the above configuration will be described with reference to the state diagrams of FIGS. 1 and 2, the operation diagrams of the rotor 110 of FIGS. 7 and 8, and the time chart of FIG. To do.
First, in a state where the coil 140 is not energized, as shown in FIG. 7A, when the rotor 110 is positioned at the counterclockwise rotation end (one end position θ1), the outer peripheral surface 111b and the first magnetic pole portion 121 are Magnetic attraction force is generated between the arc-shaped surface 121a and between the outer peripheral surface 111c and the arc-shaped surface 122a of the second magnetic pole portion 122, and the rotor 110 has a stopper (not shown) at the counterclockwise rotation end. ) Is positioned and held.
At this time, as shown in FIG. 1, the shutter blade 30 is positioned at a fully opened position where the openings 10 a and 20 a are fully opened.

In this state, when the coil 140 is energized in one direction, an N pole is generated in the first magnetic pole portion 121 and an S pole is generated in the second magnetic pole portion 122 as shown in FIG.
As a result, a repulsive force is generated between the outer peripheral surface 111b and the arcuate surface 121a of the first magnetic pole part 121, and between the outer peripheral surface 111c and the arcuate surface 122a of the second magnetic pole part 122, and the rotor 110 Begins to rotate clockwise.

When the rotor 110 rotates clockwise from the state shown in FIG. 7B, the distance between the arcuate surfaces 121a and 122a and the outer peripheral surfaces 111b and 111c is changed from the one end positions P11 and P21 to the other end positions P12 and P22. Since the rotor 110 is formed so as to continuously increase toward the other end position θ1, the clockwise rotation operation from the one end position θ1 to the other end position θ2 is performed smoothly and at high speed, as shown in FIG. Thus, the rotor 110 moves to the clockwise rotation end (the other end position θ2), is positioned by a stopper (not shown), and stops.
As a result, the shutter blade 30 smoothly performs a closing operation (shutter operation) in which the shutter blade 30 moves from the fully open position shown in FIG. 1 to the fully closed position shown in FIG. 2, and as understood from the opening waveform shown in FIG. This is performed at a higher speed than the conventional closing operation (shutter operation).

  When the coil 140 is deenergized in this fully closed position, as shown in FIG. 7D, the outer peripheral surface 111b and the first outer surface 111b are connected between the outer peripheral surface 111c and the arcuate surface 121a of the first magnetic pole part 121. Magnetic attraction force acts between the two magnetic pole portions 122 and the arcuate surface 122a, and the rotor 110 is positioned and held by a stopper (not shown) at the clockwise rotation end (other end position θ2). Yes.

On the other hand, when the coil 140 is energized in the opposite direction, opposite magnetic poles are generated in the first magnetic pole part 121 and the second magnetic pole part 122, respectively, as shown in FIG. Then, as shown in FIG. 8 (f), the rotor 110 moves stably along the reverse path to the counterclockwise rotation end (one end position θ1), and is positioned by a stopper (not shown). Stop.
Thereby, the opening operation | movement which moves the shutter blade | wing 30 from the fully closed position shown in FIG. 2 to the fully open position shown in FIG. 1 is performed smoothly. Since this opening operation does not require a particular speed, there is no problem even if it is slower than the conventional operation.

  When the coil 140 is deenergized at this fully open position, as shown in FIG. 8G, the outer peripheral surface 111c and the second outer surface 111c are connected between the outer peripheral surface 111b and the arcuate surface 121a of the first magnetic pole part 121. Magnetic attraction force acts between the arcuate surface 122a of the magnetic pole part 122, and the rotor 110 is held at the counterclockwise rotation end (one end position θ1).

As described above, the arc-shaped surfaces 121 a and 122 a of the first magnetic pole part 121 and the second magnetic pole part 122 continuously change the distance from the outer peripheral surfaces 111 b and 111 c of the rotor 110 in the rotation direction of the rotor 110. Thus, the rotor 110 can be rotated smoothly, and the speed when rotating the rotor 110 in one direction (clockwise) is faster than the speed when rotating in the other direction (counterclockwise). Thus, the shutter blade 30 can be smoothly and quickly closed (shutter operation).
Further, the outer peripheral surfaces 111b and 111c of the rotor 110 and the arc-shaped surfaces 121a and 122a of the first magnetic pole portion 121 and the second magnetic pole portion 122 are in a state where the coil 140 is not energized, and the shutter blade 30 is set to the fully open position and the fully closed position. Since they are formed so as to be held, power consumption can be reduced.

10 and 11 show another embodiment of the electromagnetic actuator according to the present invention. FIG. 10 is a plan view thereof, and FIG. 11 is an operation diagram thereof.
In this embodiment, except that the position of the boundary surface F ′ of the rotor 110 ′ is changed, the same configuration as that of the above-described embodiment is made. Therefore, the same configuration is denoted by the same reference numeral and the description thereof is omitted. .

That is, as shown in FIGS. 10A and 10B, the electromagnetic actuator 100 ′ includes a rotor 110 ′, a yoke 120, a bobbin 130, a coil 140, and the like.
As shown in FIGS. 10A and 10B, the rotor 110 ′ is formed to include a magnet portion 111 and a drive pin 112, and a boundary surface F ′ that bisects the outer peripheral surfaces 111 b and 111 c of the magnet portion 111 is formed. The drive pin 112 is provided at a position shifted by a predetermined angle.

  The outer peripheral surfaces 111b and 111c of the rotor 110 ′ and the arc-shaped surfaces 121a and 122a of the first magnetic pole part 121 and the second magnetic pole part 122 are positioned at one end of the angular range Δθ while the coil 140 is not energized. Only θ1 is formed so as to be held by a magnetic attractive force. According to this, it is possible to control the reciprocating rotation of the rotor 110 ′ by performing simple energization control of only on / off of energization in one direction with respect to the coil 140.

Next, the operation of the camera blade driving device provided with the electromagnetic actuator 100 ′ will be described with reference to the state diagrams of FIGS. 1 and 2, the operation diagram of the rotor 110 ′ of FIG. 11, and the time chart of FIG. .
First, in a state where the coil 140 is not energized, as shown in FIG. 11A, when the rotor 110 ′ is located at the counterclockwise rotation end (one end position θ 1), the outer peripheral surface 111 b and the first magnetic pole part 121. Magnetic attraction force is generated between the arc-shaped surface 121a and the outer peripheral surface 111c and the arc-shaped surface 122a of the second magnetic pole portion 122, and the rotor 110 'has a stopper ( (Not shown) is positioned and held.
At this time, as shown in FIG. 1, the shutter blade 30 is positioned at a fully opened position where the openings 10 a and 20 a are fully opened.

In this state, when the coil 140 is energized in one direction, an N pole is generated in the first magnetic pole portion 121 and an S pole is generated in the second magnetic pole portion 122 as shown in FIG.
As a result, a repulsive force is generated between the outer peripheral surface 111b and the arcuate surface 121a of the first magnetic pole part 121, and between the outer peripheral surface 111c and the arcuate surface 122a of the second magnetic pole part 122, and the rotor 110 'Starts to rotate clockwise.

When the rotor 110 ′ rotates clockwise from the state shown in FIG. 11B, the distance between the arcuate surfaces 121a and 122a and the outer peripheral surfaces 111b and 111c is changed from the one end positions P11 and P21 to the other end positions P12 and P22. 11 (c), the rotor 110 ′ is smoothly rotated at a high speed in the clockwise direction from the one end position θ1 to the other end position θ2. As shown, the rotor 110 ′ moves to the clockwise rotation end (the other end position θ2), is positioned by a stopper (not shown), and stops.
Thus, the shutter blade 30 smoothly performs a closing operation (shutter operation) in which the shutter blade 30 moves from the fully open position shown in FIG. 1 to the fully closed position shown in FIG.

  When the coil 140 is deenergized in this fully closed position, the magnetic poles generated by the electromagnetic force in the first magnetic pole part 121 and the second magnetic pole part 122 disappear as shown in FIG. The magnetic force that urges the rotor 110 'to rotate counterclockwise between the outer peripheral surface 111b and the arcuate surface 121a of the first magnetic pole part 121 and between the outer peripheral surface 111c and the arcuate surface 122a of the second magnetic pole part 122. The attractive suction force acts.

Then, as shown in FIG. 11E, the rotor 110 ′ moves stably along the reverse path to the counterclockwise rotation end (one end position θ1) and is positioned by a stopper (not shown). And stop.
Thereby, the opening operation | movement which moves the shutter blade | wing 30 from the fully closed position shown in FIG. 2 to the fully open position shown in FIG. 1 is performed smoothly.

  When the coil 140 is deenergized at this fully open position, as shown in FIG. 11A, the outer peripheral surface 111c and the second outer surface 111c are formed between the outer peripheral surface 111b and the arcuate surface 112a of the first magnetic pole portion 112. Magnetic attraction force acts between the arcuate surface 122a of the magnetic pole portion 122, and the rotor 110 'is held at the counterclockwise rotation end (one end position θ1).

As described above, the arc-shaped surfaces 121a and 122a of the first magnetic pole part 121 and the second magnetic pole part 122 continuously change the distance between the outer peripheral surfaces 111b and 111c of the rotor 110 'in the rotation direction of the rotor 110'. Thus, the rotor 110 ′ can be smoothly rotated and the holding force at the counterclockwise rotation end (one end position θ 1) can be maximized, and the shutter blade 30 can be closed ( (Shutter operation) can be smoothly performed from a high holding force state.
Further, the outer peripheral surfaces 111b and 111c of the rotor 110 ′ and the arc-shaped surfaces 121a and 122a of the first magnetic pole portion 121 and the second magnetic pole portion 122 hold the shutter blade 30 only in the fully open position when the coil 140 is not energized. Thus, the opening / closing operation of the shutter blade 30 can be controlled by simple energization control for turning on / off the energization in the direction in which the coil 140 is closed.

In the above embodiment, the distance (magnetic gap) between the first magnetic pole part 121 and the second magnetic pole part 122 and the rotors 110 and 110 ′ is continuously increased from one end side to the other end side of the arcuate surfaces 121a and 122a. Although the change pattern to increase was shown, it is not limited to this, and conversely, a change pattern that continuously decreases from one end side to the other end side may be adopted.
In the above embodiment, the case where the electromagnetic actuator is applied as a drive source for driving the shutter blade 30 for the camera has been described. However, the present invention is not limited to this, and other blades such as a diaphragm blade and an ND filter blade. May be used as a drive source for driving the. Moreover, although the pair of shutter blades 31 and 32 is shown as the shutter blade 30, it is not limited to this, and a single shutter blade may be adopted.

  As described above, while achieving the electromagnetic actuator of the present invention, simplification of structure, miniaturization, cost reduction, etc., the driving torque, rotational speed, responsiveness, impact resistance performance when the rotor rotates in one direction Therefore, it can be applied as a drive source for driving blades such as shutter blades and diaphragm blades of cameras, and is also useful as a drive source in other fields that require rotational driving force. .

It is a top view which shows one Embodiment of the blade drive device for cameras provided with the electromagnetic actuator which concerns on this invention. It is a top view which shows one Embodiment of the blade drive device for cameras provided with the electromagnetic actuator which concerns on this invention. FIG. 3 is a developed partial cross-sectional view of the camera blade driving device shown in FIGS. 1 and 2. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of an electromagnetic actuator according to the present invention, wherein (a) is a plan view showing a state where a rotor is at one end position, and (b) is a plan view showing a state where the rotor is at the other end position. . It is the elements on larger scale which expanded a part of electromagnetic actuator shown in FIG. It is the graph which showed the relationship between the space | interval of a rotor and a magnetic pole part in an electromagnetic actuator, holding force, and the rotational speed (shutter speed) of a rotor. The operation of the electromagnetic actuator shown in FIG. 4 will be described. (A), (b), (c), and (d) are plan views (operation diagrams) showing respective operation states. The operation of the electromagnetic actuator shown in FIG. 4 will be described. (E), (f), and (g) are plan views (operation diagrams) showing respective operation states. It is a time chart which shows the electricity supply control to a coil, and the opening waveform of a shutter blade | wing. 4A and 4B show another embodiment of the electromagnetic actuator according to the present invention, wherein FIG. 5A is a plan view showing a state where the rotor is at one end position, and FIG. 5B is a plan view showing a state where the rotor is at the other end position. is there. FIG. 10 illustrates the operation of the electromagnetic actuator shown in FIG. 10, and (a), (b), (c), (d), and (e) are plan views (operation diagrams) showing respective operation states. . It is a time chart which shows the electricity supply control to a coil, and the opening waveform of a shutter blade | wing.

Explanation of symbols

10 Ground plane (substrate)
11 Support shaft 12 Pin 13 Protrusion 14 Connecting portion 15a, 15b Support shaft 20 Back plate (substrate)
10a, 20a Opening 10b Through-hole 30 (31, 32) Shutter blade 31a, 32a Circular hole 31b, 32b Long hole 100, 100 'Electromagnetic actuator (drive source)
110, 110 'Rotor L Rotating shaft F, F' Boundary surface 111 Magnet portion 111b, 111c Outer peripheral surface 112 Drive pin 120 Yoke 121 First magnetic pole portion 121a Arc-shaped surface 122 Second magnetic pole portion 122a Arc-shaped surface 130 Bobbin 140 Coil 150 Presser plate θ1 One end position θ2 The other end position Δθ Angle range (operating angle)
P11, P21 one end position P12, P22 other end position

Claims (9)

A rotor having a cylindrical outer peripheral surface magnetized by being divided into two in the circumferential direction, an exciting coil, and an arcuate surface facing the outer peripheral surface of the rotor are defined, and are different from each other by energizing the coil. An electromagnetic actuator comprising a yoke having a first magnetic pole part and a second magnetic pole part for generating magnetic poles, and generating a driving force by rotating a predetermined angular range,
The arc-shaped surfaces of the first magnetic pole part and the second magnetic pole part are formed so as to continuously change the distance from the outer peripheral surface of the rotor in the rotation direction of the rotor,
An electromagnetic actuator characterized by that. When the minimum value of the interval is X and the maximum value is Y, the following conditional expression X <Y <2X
The electromagnetic actuator according to claim 1, wherein: The outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole part and the second magnetic pole part are formed so as to hold the rotor at both end positions of the angle range in a state where the coil is not energized,
The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is characterized in that The outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole part and the second magnetic pole part are formed so as to hold the rotor only at one end position of the angle range in a state where the coil is not energized.
The electromagnetic actuator according to claim 1, wherein the electromagnetic actuator is characterized in that A substrate having an opening, and a blade rotatably supported by the substrate to perform an opening operation for moving the opening to a fully opened position and a closing operation for moving the opening to a fully closed position. And a blade drive device for a camera comprising a drive source for driving the blade,
The drive source has a cylindrical outer peripheral surface that is magnetized by being divided into two in the circumferential direction, and a rotor that drives the blade to open and close, an excitation coil, and an arc-shaped surface that faces the outer peripheral surface of the rotor, respectively. Including a yoke having a first magnetic pole part and a second magnetic pole part for defining and generating different magnetic poles by energizing the coil,
The arc-shaped surfaces of the first magnetic pole part and the second magnetic pole part are formed so as to continuously change the distance from the outer peripheral surface of the rotor in the rotation direction of the rotor,
A blade drive device for a camera. When the minimum value of the interval is X and the maximum value is Y, the following conditional expression X <Y <2X
The camera blade driving device according to claim 5, wherein: The interval is formed such that a magnetic attractive force generated when the blade is in the fully closed position is larger than a magnetic attractive force generated when the blade is in the fully open position.
The camera blade driving device according to claim 5 or 6, The outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole part and the second magnetic pole part are formed so as to hold the blades in the fully open position and the fully closed position, respectively, while the coil is not energized.
The camera blade driving device according to claim 7. The outer peripheral surface of the rotor and the arc-shaped surfaces of the first magnetic pole part and the second magnetic pole part are formed so as to hold the blade only in the fully open position in a state where the coil is not energized.
The camera blade driving device according to claim 7.

Images