JP2009229610A - Sector device and camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sector device having self-holding power and attaining high-speed operation. <P>SOLUTION: A repulsion boundary position where the rotational moment by the repulsive force of a magnet is reversed is provided between a sector opening position and a sector closing position, and a sector 2 is moved by a shape memory alloy wire for closing induction 8, from the sector opening position to the repulsion boundary position, and is moved by a shape memory alloy wire for opening induction 7, from the sector closing position to the repulsion boundary position. After passing over the repulsion boundary position, the sector 2 is moved by the rotational moment by the repulsive force of the magnet. The sector 2 is held at the sector-opening position and the sector closing position, respectively by the rotational moment by the repulsive force of the magnet. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sector apparatus and a camera including the same.

  In recent years, with the digitalization of cameras, the driving of sectors such as shutters and diaphragms has been realized by electromagnetic mechanisms such as step motors.

  In such a camera, since it is required to suppress the consumption of a battery serving as a power source for a step motor or the like, it is desirable that a sector such as a shutter blade has a self-holding force that can maintain a state even when no power is supplied. .

  Therefore, the inventors of the present invention have proposed a sector device that drives a sector with an artificial muscle wire and holds the sector at a predetermined position using the attractive force of a magnetic material (Patent Document 1).

However, since the artificial muscle wire has a low operating speed, there is a concern that the sector apparatus cannot increase the moving speed of the sector.
JP 2006-284803 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a sector apparatus and a camera that have a self-holding force and can operate at high speed.

  The sector device of the present invention includes a base plate having an opening through which imaging light passes, a position that is rotatably supported by a support shaft provided on the base plate, and closes the opening (hereinafter referred to as a closed position) and the opening. In a sector apparatus having a sector that rotates between a position for opening (hereinafter referred to as an open position), a first magnet fixed to the sector, a first magnet fixed to the base plate, A second magnet facing each other, the first magnet and the second magnet facing each other with the same magnetic pole, a magnetic force center line of the first and second magnets passes through the center of the support shaft, When the sector is at a specific position between the open position and the closed position (hereinafter referred to as a boundary position), the magnetic force center line of the first magnet and the magnetic force center line of the second magnet coincide with each other. And the sector is An opening inducing actuator for rotating the sector toward the boundary position when the chain position is in position and passing the boundary position; and when the sector is in the open position, the sector is moved to the boundary position. And a closing induction actuator that is rotated toward and passes through the boundary position.

  In the planar shape of the first magnet and the second magnet in a plane orthogonal to the support shaft, the opposing sides of the first magnet and the second magnet have the support shaft as a common center. You may arrange | position so that the circular arc to make may be made.

  The actuator may move the sector from the closed position or the open position to a position where the direction of the rotational moment due to repulsive force acting between the first magnet and the second magnet is reversed.

  The opening induction actuator has both ends fixed to the base plate, applies tension to the sector in the contracted state, rotates the sector from the closed position toward the boundary position, and in the relaxed state, the sector The closing induction actuator is fixed at both ends to the base plate to exert tension on the sector in a contracted state, and the sector is moved from the open position. A second artificial muscle that is rotated toward the boundary position and does not exert tension on the sector in a relaxed state may be used.

  In addition, a shape memory alloy or a conductive polymer material is used for the first and second artificial muscles.

  A camera according to the present invention includes a sector device having the above-described characteristics.

  Since the sector device of the present invention assists the actuator with a repulsive force acting between two magnets, the sector can be driven at a high speed.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a view of a sector apparatus 100 according to the present invention as viewed from above, and FIG. 2 is a view of the sector apparatus 100 as viewed from below.

  The sector device 100 is used as a shutter of an electronic camera and includes a base plate 1 and a sector 2 as shown in FIGS. The base plate 1 is provided with an opening 3 through which imaging light passes, and the sector 2 is supported by a support shaft 4 fixed to the base plate 1 so as to shield the opening 3 (hereinafter referred to as a closed position) and an opening. 3 is rotated between exposure positions (hereinafter referred to as open positions). Further, the base plate 1 is provided with an arc-shaped guide groove 5 centered on the support shaft 4, a guide bar 6a is erected on the upper surface of the sector 2, and a guide bar 6b is erected on the lower surface. Guided to the guide groove 5.

  Further, an opening guiding shape memory alloy wire 7 and a closing guiding shape memory alloy wire 8 are stretched on the base plate 1. The wires 8 are in contact with the guide rods 6b. A first magnet 9 is fixed to the sector 2 and a second magnet 10 is fixed to the base plate 1, and the first magnet 9 and the second magnet 10 have the same magnetic poles facing each other. In addition, two support electrodes 11 to 14 in total are fixed to the base plate 1 in the vicinity of two apexes facing each other diagonally.

The opening-inducing shape memory alloy wire 7 is on the upper surface side of the sector 2 and has one end fixed to the support electrode 11 and the other end fixed to the support electrode 12. When a voltage is applied between the support electrode 11 and the support electrode 12 to energize the opening guide shape memory alloy wire 7, the opening guide shape memory alloy wire 7 contracts. Since the tension generated in the shape memory alloy wire 7 during contraction acts on the guide rod 6a, the sector 2 rotates around the support shaft 4 in the direction from the closed position toward the open position. When the shape-inducing shape memory alloy wire 7 is not energized, that is, when the shape-inducing shape memory alloy wire 7 is loose, the shape-inducing shape memory alloy wire 7 does not act on the guide rod 6a. .

  The shape-inducing shape memory alloy wire 8 for closing guidance is on the lower surface side of the sector 2 and has one end fixed to the support electrode 13 and the other end fixed to the support electrode 14. When a voltage is applied between the support electrode 13 and the support electrode 14 to energize the closing induction shape memory alloy wire 8, the closing induction shape memory alloy wire 8 contracts. Since the tension generated in the shape memory alloy wire 8 during contraction acts on the guide rod 6b, the sector 2 rotates around the support shaft 4 in the direction from the open position to the closed position. When the shape-inducing shape memory alloy wire 8 is not energized, that is, when the shape-inducing shape memory alloy wire 8 is in a relaxed state, the shape-inducing shape memory alloy wire 8 does not act on the guide rod 6b. .

  The opening induction shape memory alloy wire 7 and the closing induction shape memory alloy wire 8 are titanium-nickel (Ti-Ni) alloys. The thin wire of this alloy has a soft and supple relaxed state like nylon thread at room temperature, but when energized and heated, it becomes a contracted state that shortens the length and becomes tough. .

  FIG. 3 is a diagram for explaining the operation of the first magnet 9 and the second magnet 10. In addition, the broken line in a figure shows the magnetic force line, and the dashed-dotted line has shown the centerline of the magnetic force. As shown in FIG. 3, the first magnet 9 is attached to the sector 2 so that the center line of the magnetic force is directed toward the center of the support shaft 4 of the sector 2. Similarly, the second magnet 10 is also attached to the base plate 1 so that the center line of the magnetic force is directed toward the center of the support shaft 4. Further, when the relative angle between the center line of the magnetic force of the first magnet 9 and the center line of the magnetic force of the second magnet 10 is changed by the rotation of the sector 2, the repulsive force that the first magnet 9 receives from the second magnet 10. The direction of changes.

  As shown in FIG. 3A, when the sector 2 is placed at a position where the center line of the magnetic force of the first magnet 9 coincides with the center line of the magnetic force of the second magnet 10, the repulsive force acting on the first magnet 9 is obtained. Since the line of action passes through the center c of the support shaft 4 of the sector 2, the first magnet 9 does not have a rotational moment around the center c. Hereinafter, in this specification, the rotational position of the sector 2 at this time will be referred to as a rebound boundary position.

  As shown in FIG. 3B, when the sector 2 is rotated clockwise from the rebound boundary position, the magnetic force center line of the first magnet 9 is biased to the left with respect to the magnetic force center line of the second magnet 10. The action line of repulsive force acting on the first magnet 9 passes through the left side of the rotation center c of the sector 2. Therefore, a clockwise rotational moment is generated in the first magnet 9.

  As shown in FIG. 3C, when the sector 2 is rotated counterclockwise from the rebound boundary position, the center line of the magnetic force of the first magnet 9 is set to the right with respect to the center line of the magnetic force of the second magnet 10. The action line of repulsive force acting on the first magnet 9 is passed to the right of the rotation center c of the sector 2. Therefore, a counterclockwise rotational moment is generated in the first magnet 9.

  Here, the relationship between the rotational position of the sector 2 and the rotational moment due to the repulsive force acting on the first magnet 9 will be described.

  As shown in FIG. 4 (a), when the sector 2 is at the rebound boundary position, the repulsive force acting on the first magnet 9 is directed to the center c of the support shaft 4 of the sector 2, so There is no rotational moment. Therefore, the sector 2 does not rotate (see FIG. 3A).

  If the sector 2 slightly rotates clockwise from the rebound boundary position, a rotational moment that rotates the sector 2 clockwise is generated, and the sector 2 moves to the closed position (see FIG. 3B).

  If the sector 2 is slightly rotated counterclockwise from the rebound boundary position, a rotational moment that causes the sector 2 to rotate counterclockwise is generated, and the sector 2 moves to the open position (see FIG. 3C). .

  As shown in FIG. 4B, when the sector 2 shields the opening 3, that is, when the sector 2 is placed in the closed position, a rotational moment that causes the sector 2 to rotate clockwise is generated. Held in a closed position.

  As shown in FIG. 4C, when the sector 2 moves away from the opening 3, that is, when the sector 2 is placed in the open position, a rotational moment that causes the sector 2 to rotate counterclockwise is generated. Is held in the open position.

  As described above, the direction of the rotational moment generated in the sector 2 by the repulsive force received by the first magnet 9 is reversed with the rebound boundary position as a boundary. In other words, between the rebound boundary position and the open position, the sector 2 works in the direction toward the open position, and between the rebound boundary position and the closed position, the sector 2 works in the direction toward the closed position.

  In the present embodiment, the first magnet 9 and the second magnet 10 are formed in an arc shape, and the first magnet 9 and the second magnet 10 are arranged concentrically around the support shaft 4. Since the gap between the first magnet 9 and the second magnet 10 is made constant even when the sector 2 rotates, the first magnet 9 receives from the second magnet 10 depending on the rotational position of the sector 2. The repulsive force does not change rapidly. Therefore, the rotational speed of sector 2 does not change suddenly depending on the rotational position of sector 2.

  FIG. 5 is a diagram for explaining the operation of the sector apparatus 100 shown in FIGS. 1 and 2, and FIGS. 5A to 5C are diagrams showing a process in which the sector 2 moves from the open position to the closed position. It is the figure seen from the lower surface of the baseplate 1 of a sector apparatus, ie, the figure seen from the same direction as FIG. 5D and 5E are views showing a process in which the sector 2 moves from the closed position to the open position, and is a view seen from the upper surface of the base plate 1 of the sector device, that is, the same direction as FIG. It is the figure seen from.

  In the present embodiment, when the sector 2 is moved from the open position to the closed position, the sector 2 is moved from the open position by using the shape-inducing shape alloy wire 8 for closing, and the rebound boundary position is exceeded. When the rebound boundary position is exceeded, the rotational moment due to the repulsive force acting on the first magnet 9 acts in the direction in which the sector 2 is directed to the closed position. In addition, the rotational operation speed of the sector 2 due to the rotational moment due to the repulsive force acting on the first magnet 9 is faster than the rotational operation speed of the shape-inducing shape memory alloy wire 8 for closing guidance. Move between them at high speed.

  Similarly, when the sector 2 is moved from the closed position to the open position, the shape memory alloy wire 7 for opening guidance is used to move the sector 2 from the open position to exceed the rebound boundary position. When the rebound boundary position is exceeded, the rotational moment due to the repulsive force acting on the first magnet 9 acts in a direction toward the sector 2 toward the open position, but the rotational speed of the sector 2 due to the rotational moment due to the repulsive force acting on the first magnet 9 Is faster than the rotational operation speed by the shape memory alloy wire 7 for opening guidance, so the sector 2 moves at a high speed between the rebound boundary position and the open position.

  Now, as shown in FIG. 5A, when the sector 2 is in the open position, the repulsive force acting on the first magnet 9 generates a rotational moment that urges the sector 2 toward the open position. 2 is held in the open position. Therefore, it is not necessary to energize the shape memory alloy wire 7 for opening guidance in order to hold the sector 2 in the open position.

  In the state shown in FIG. 5 (a), when the closing-inducing shape memory alloy wire 8 is energized, the closing-inducing shape memory alloy wire 8 contracts and the sector 2 starts to rotate toward the closing position. The rebound boundary position is exceeded (see FIG. 5B).

  When the sector 2 exceeds the rebound boundary position, the repulsive force acting on the first magnet 9 generates a rotational moment that urges the sector 2 toward the closed position. For this reason, when the sector 2 exceeds the rebound boundary position, the energization to the closing guiding shape memory alloy wire 8 may be stopped.

  As described above, when the closing-inducing shape memory alloy 8 rotates the sector 2 in the open position toward the rebound boundary position and passes the rebound boundary position, the repulsive force acting on the first magnet 9 is changed to the sector 2. Since it works in the direction toward the closed position, it rotates at a high speed thereafter. That is, the closing-inducing shape memory alloy 8 functions as a trigger for exciting the movement of the sector 2 toward the closing position.

  Eventually, as shown in FIG. 5C, the sector 2 reaches the closed position and stops. Thereafter, the sector 2 is held in the closed position by the rotational moment due to the repulsive force acting on the first magnet 9. Therefore, it is not necessary to energize the shape-inducing alloy wire 8 for closing guidance.

  As shown in FIG. 5 (d), when the opening guide shape memory alloy 7 is energized when the sector 2 is in the closed position, the opening guide shape memory alloy wire 7 contracts and the sector 2 moves toward the open position. It begins to rotate and eventually crosses the rebound boundary position.

  When the sector 2 exceeds the rebound boundary position, the repulsive force acting on the first magnet 9 generates a rotational moment that urges the sector 2 toward the open position. For this reason, when the sector 2 exceeds the rebound boundary position, the energization to the opening guide shape memory alloy 7 may be stopped.

  As described above, when the opening-inducing shape memory alloy 7 rotates the sector 2 in the closed position toward the rebound boundary position and passes through the rebound boundary position, the repulsive force acting on the first magnet 9 is changed to the sector 2. Since it works in the direction toward the open position, it rotates at a high speed thereafter. That is, the shape-inducing shape memory alloy 7 for opening guidance functions as a trigger for exciting the movement toward the opening position of the sector 2.

  Eventually, as shown in FIG. 5E, the sector 2 reaches the open position and stops. Thereafter, the sector 2 is held at the open position by the rotational moment due to the repulsive force acting on the first magnet 9. Therefore, it is not necessary to energize the shape memory alloy 7 for opening guidance.

  In this way, if the sector 2 is moved with the shape memory alloy wire until it passes through the rebound boundary position, the sector 2 can be driven only by the rotational moment due to the repulsive force acting on the first magnet 9 thereafter. Thereby, since the energization time to the shape memory alloy wire is also extremely short, consumption of the battery or the like is suppressed.

  In this embodiment, an actuator using artificial muscles is used, but the type of actuator is not limited to this. Moreover, it may replace with a shape memory alloy wire, and may use the electric field expansion-contraction characteristic using a conductive polymer.

  If the rebound boundary position is set so that the sector 2 passes through the rebound boundary position before the opening of the opening 3 starts when the sector 2 moves from the open position toward the closed position, The time required from the start of closure to complete closure can be shortened.

It is the figure which looked at the sector apparatus based on this invention from the upper surface. It is the figure which looked at the sector apparatus based on this invention from the lower surface. It is a figure explaining the effect | action of a 1st magnet and a 2nd magnet. It is a figure explaining the relationship between the rotational position of a sector, and the rotational moment by the repulsive force which acts on a 1st magnet. It is a figure explaining the effect | action of the sector apparatus based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base plate 2 Sector 3 Opening 4 Support shaft 5 Guide groove 6a, 6b Guide rod 7 Shape memory alloy wire for opening guidance 8 Shape memory alloy wire for closing guidance 9 First magnet 10 Second magnet 11-14 Support electrode

Claims (7)

A base plate having an aperture through which imaging light passes;
A sector that is rotatably supported by a support shaft provided on the base plate and rotates between a position that closes the opening (hereinafter referred to as a closed position) and a position that opens the opening (hereinafter referred to as an open position). In a sector device having
A first magnet fixed to the sector;
A second magnet fixed to the base plate and facing the first magnet;
The first magnet and the second magnet face each other with the same magnetic pole,
A center line of magnetic force of the first and second magnets passes through the center of the support shaft,
When the sector is at a specific position between the open position and the closed position (hereinafter referred to as a boundary position), the magnetic force center line of the first magnet and the magnetic force center line of the second magnet coincide with each other. Are arranged to
An opening induction actuator that, when the sector is in the closed position, rotates the sector toward the boundary position and passes the boundary position;
A sector apparatus comprising: a closing induction actuator that rotates the sector toward the boundary position and passes the boundary position when the sector is in the open position. In the plane shape of the first magnet and the second magnet in a plane orthogonal to the support shaft,
The sector device according to claim 1, wherein opposing sides of the first magnet and the second magnet form an arc having the common axis as the support shaft. The actuator moves the sector from the closed position or the open position to a position where a direction of a rotational moment due to repulsive force acting between the first magnet and the second magnet is reversed. Item 3. The sector device according to Item 1 or 2. The opening induction actuator is fixed at both ends to the base plate, applies tension to the sector in the contracted state, rotates the sector from the closed position toward the boundary position, and applies tension to the sector in the relaxed state. It is composed of the first artificial muscle that does not reach,
The closing induction actuator is fixed at both ends to the base plate, applies tension to the sector in the contracted state, rotates the sector from the open position toward the boundary position, and applies tension to the sector in the relaxed state. The sector device according to any one of claims 1 to 3, wherein the sector device is configured by a second artificial muscle that does not reach. The sector device according to claim 4, wherein the first and second artificial muscles are shape memory alloys. The sector device according to claim 4, wherein the first and second artificial muscles are conductive polymer substances.   A camera comprising the sector device according to claim 1.

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