Blade drive device and imaging device equipped therewith

Abstract

To provide a blade driving device that can prevent rebound of blades when they are stopped, while avoiding an increase in the thickness of the device in a direction along a driving shaft.SOLUTION: A blade driving device 1 comprises: a bottom board 10 that is provided with an opening S; blades 21-24 that are movable between closed positions and open positions; a rotational driving member 50 that is connected to the blades 21-24 and can rotate around a driving shaft 18 to move the blades 21-24 between the closed positions and open positions; a brake member 90 configured to be rotatable near the rotational driving member 50; and a brake pad 100 that is in slide contact with an outer peripheral surface 94A of the brake member 90 to prevent the rotation of the brake member 90 with the friction. The rotational driving member 50 has pushers 54, 55 configured to be brought into contact with the brake member 90 to push the brake member 90 before the end of at least one operation of an opening operation and a closing operation.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a blade drive device and an imaging device provided with the same, and particularly to a blade drive device used as a shutter in a digital camera or the like.

Background Art

[0002] In a digital camera or the like, a blade drive mechanism is often provided that moves one or more shutter blades connected to a drive lever by rotating the drive lever, and the shutter blades open and close an exposure aperture. The shutter blades in such a blade drive mechanism abut against a stopper and stop, but at that time, they may bounce back and a part of the shutter blades may enter the exposure aperture, which may have an adverse effect on shooting. In order to suppress such bouncing back of the shutter blades, it is also conceivable to arrange a brake member that contacts the drive lever and can brake the drive lever coaxially with the drive lever (see, for example, Patent Document 1).

[0003] In such a conventional braking mechanism for a drive lever, a washer is arranged between the brake member and the base plate, and a spring washer is arranged between the brake member and the shaft portion of the drive lever. As a result, the brake member is axially pressed, and when the brake member is pushed by the shutter blade and rotates, a frictional force is generated between the brake member and the washer and the spring washer, and the drive lever is braked by this frictional force. However, in such a conventional braking mechanism, since it is necessary to arrange the spring washer, the brake member, and the washer coaxially in the axial direction along the drive lever, the thickness along the axial direction inevitably becomes large, and it is difficult to effectively realize the thinning of the camera.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] This invention has been made in view of the problems of the prior art, and aims to provide a blade drive device that can suppress the rebound of the blade when it stops while avoiding increasing thickness in the direction along the drive shaft, and an imaging device equipped therewith. [Means for solving the problem]

[0006] According to a first aspect of the present invention, a blade drive device is provided that can suppress the rebound of the blade when it stops while avoiding increasing thickness in the direction along the drive shaft. This blade drive device comprises a base plate having an opening formed therein, at least one blade movable between a closed position that closes the opening and an open position that opens the opening, a rotational drive member directly or indirectly connected to the at least one blade and capable of moving the at least one blade from the closed position to the open position by rotating from a first rotational position to a second rotational position about the drive shaft, and moving the at least one blade from the open position to the closed position by rotating from the second rotational position to the first rotational position, a braking member configured to be movable in the vicinity of the rotational drive member, and a sliding contact member that slides against the outer circumferential surface of the braking member and suppresses the movement of the braking member by friction. The rotational drive member has a contact portion configured to contact and push the braking member before the completion of at least one of the following operations: an opening operation in which it rotates from the first rotational position to the second rotational position, and a closing operation in which it rotates from the second rotational position to the first rotational position.

[0007] According to a second aspect of the present invention, an imaging device is provided comprising the above-mentioned blade drive device and an image sensor arranged on a surface in which light transmitted through the blade drive device forms an image. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing a blade drive device in one embodiment of the present invention. [Figure 2]Figure 2 is an exploded perspective view of the blade drive device shown in Figure 1. [Figure 3] Figure 3 is a front view showing the base plate in the blade drive device shown in Figure 1. [Figure 4A] Figure 4A is a front view of the rotary drive member in the blade drive device shown in Figure 2. [Figure 4B] Figure 4B is a rear view of the rotary drive member shown in Figure 4A. [Figure 4C] Figure 4C is a right side view of the rotary drive member shown in Figure 4A. [Figure 5A] Figure 5A is a front view of the blade drive lever in the blade drive device shown in Figure 2. [Figure 5B] Figure 5B is a rear view of the blade drive lever shown in Figure 5A. [Figure 5C] Figure 5C is a right side view of the blade drive lever shown in Figure 5A. [Figure 6] Figure 6 is a front view of the link member in the blade drive device shown in Figure 2. [Figure 7] Figure 7 is a perspective view of the braking member in the blade drive device shown in Figure 2. [Figure 8] Figure 8 is a perspective view of the brake pad in the vane drive device shown in Figure 2. [Figure 9A] Figure 9A is a schematic plan view showing the blades in the closed position of the blade drive device shown in Figure 1. [Figure 9B] Figure 9B is a schematic plan view showing the blades in the open position in the blade drive device shown in Figure 1. [Figure 10A] Figure 10A is a schematic front view showing the state of the rotary drive member just before it moves from the first rotation position shown in Figure 9A to the second rotation position shown in Figure 9B. [Figure 10B] Figure 10B is a schematic front view showing the state in which the rotary drive member has rotated from the state shown in Figure 10A to the second rotation position. [Figure 10C] Figure 10C is a schematic front view showing the state of the rotary drive member just before it moves from the second rotational position state shown in Figure 9B to the first rotational position. [Figure 10D] FIG. 10D is a front view schematically showing a state in which the rotation driving member has rotated to a first rotation position from the state shown in FIG. 10C. [Figure 11] FIG. 11 is a front view schematically showing a braking mechanism of a blade driving device in another embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the blade driving device and the imaging device according to the present invention will be described in detail with reference to FIGS. 1 to 11. In FIGS. 1 to 11, the same or corresponding components are denoted by the same reference numerals, and redundant descriptions are omitted. Also, in FIGS. 1 to 11, the scales and dimensions of each component may be exaggerated or some components may be omitted. In the following description, unless otherwise specified, terms such as "first" and "second" are used only to distinguish components from each other and do not represent a specific order or sequence.

[0010] FIG. 1 is a perspective view showing a blade driving device 1 in an embodiment of the present invention, and FIG. 2 is an exploded perspective view. The blade driving device 1 in the present embodiment will be described as a shutter device incorporated in an optical device such as a camera, but this is merely an example, and the blade driving device according to the present invention is not limited to such a shutter device application.

[0011] As shown in FIGS. 1 and 2, the blade driving device 1 in the present embodiment includes a base plate 10 in which a rectangular opening (exposure opening) S is formed, four blades 21 to 24 housed in a space formed between the base plate 10 and a cover (not shown), and blade arms 31 and 32 connected to the blades 21 to 24. This blade driving device 1 is incorporated in an imaging device provided with an imaging element (not shown) such as a CCD or a CMOS sensor, and the +Z direction is the subject side. Light from the subject passes through the opening S of the base plate 10 and enters the imaging element disposed on the -Z direction side of the blade driving device 1. Depending on the configuration of the camera, the -Z direction may be the subject side and the +Z direction may be the imaging element side.

[0012] Each of the blades 21 to 24 is a thin plate-shaped member extending in the X direction as a whole, and the four blades 21 to 24 are stacked in order in the -Z direction. The blade 21 is connected to the blade arms 31 and 32 by pins 41 and 42 respectively, the blade 22 is connected to the blade arms 31 and 32 by pins 43 and 44 respectively, the blade 23 is connected to the blade arms 31 and 32 by pins 45 and 46 respectively, and the blade 24 is connected to the blade arms 31 and 32 by pins 47 and 48 respectively.

[0013] A circular hole 33 is formed at the end of the blade arm 31, and a substantially rectangular lever connection hole 34 is formed at a position slightly away from this circular hole 33. The blade arm 31 is configured to be rotatable around the center of the circular hole 33. Further, a circular hole 36 through which the pin 35 is inserted is formed at the end of the blade arm 32, and the pin 35 inserted into this circular hole 36 is press-fitted into a pin hole (not shown) formed in the floor 10. Thereby, the blade arm 32 is configured to be rotatable around the pin 35.

[0014] In this way, a link mechanism is constituted by the blades 21 to 24 and the blade arms 31 and 32. That is, when the blade arm 31 rotates around the center of the circular hole 33 and the blade arm 32 rotates around the pin 35, the blades 21 to 24 move mainly in the Y direction while changing the overlapping area with each other by the link mechanism.

[0015] FIG. 3 is a front view showing the floor 10. As shown in FIG. 3, the floor 10 has a substantially cylindrical shaft portion 17 with a circular hole 11 formed at the center. This shaft portion 17 has a claw portion 17A extending in the +Y direction. As shown in FIG. 2, a drive shaft 18 extending in the Z direction is inserted and fixed into the circular hole 11 of this shaft portion 17. Further, a circular hole 12 is formed in the floor 10 at a position away from the shaft portion 17, and an arc groove 13 is formed along an arc centered on this circular hole 12.

[0016] As shown in Figures 1 and 2, the blade drive device 1 includes an electromagnetic coil unit 80, a rotary drive member 50 that is rotationally driven by the electromagnetic coil unit 80, a blade drive lever 60 that is rotated by the rotary drive member 50, and a link member 70 that connects the rotary drive member 50 and the blade drive lever 60.

[0017] Figure 4A is a front view of the rotary drive member 50, Figure 4B is a rear view, and Figure 4C is a right side view. As shown in Figures 4A to 4C, the rotary drive member 50 has a shaft portion 51 through which a drive shaft 18 is inserted, a rotor 52 fixed to the +Z side end of the shaft portion 51, an arm portion 53 extending radially outward from the shaft portion 51, and two pushers 54 and 55 extending radially outward from the shaft portion 51. The rotor 52 is made up of permanent magnets magnetized with different magnetic poles 52A and 52B in the diametrical direction. For example, magnetic pole 52A is the south pole and magnetic pole 52B is the north pole. The rotary drive member 50 is rotatably mounted on a drive shaft 18 which is attached to a circular hole 11 in the base plate 10.

[0018] Returning to Figure 2, the electromagnetic coil unit 80 includes four metal yokes 81A, 81B, 82A, and 82B, two bobbins 83A and 83B, and two coils 84 wound around each bobbin 83A and 83B. The coils 84 are connected to a control unit (not shown), which controls the energization of the coils 84. This electromagnetic coil unit 80 and the rotor 52 of the rotary drive member 50 constitute a motor (drive unit) that rotates the rotary drive member 50 around the drive shaft 18.

[0019] Yokes 81A and 81B are arranged overlapping in the Z direction, and yokes 82A and 82B are arranged overlapping in the Z direction. Yokes 81A, 81B and yokes 82A, 82B are arranged opposite each other in the X direction, surrounding the rotor 52 of the rotary drive member 50. The ends of each yoke 81A, 81B, 82A, and 82B are inserted into the hollow parts of bobbins 83A and 83B. In the hollow part of bobbin 83A, yokes 81B and 82A are arranged overlapping in the Z direction, and in the hollow part of bobbin 83B, yokes 81A and 82B are arranged overlapping in the Z direction.

[0020] Figure 5A is a front view of the blade drive lever 60, Figure 5B is a rear view, and Figure 5C is a right side view. As shown in Figures 5A to 5C, the blade drive lever 60 has a shaft portion 61 extending in the Z direction, an arm portion 62 curving outward from the shaft portion 61, an arm portion 63 curving outward from the shaft portion 61, an arm portion 64 extending linearly from the shaft portion 61, and a drive pin 65 extending in the -Z direction from the end of the arm portion 64.

[0021] The -Z-direction end 61A of the shaft portion 61 of the blade drive lever 60 is rotatably inserted into the circular hole 12 of the base plate 10 and further protrudes from the base plate 10 in the -Z direction. The end 61A of the shaft portion 61 of the blade drive lever 60 that protrudes from the base plate 10 in the -Z direction is inserted into the circular hole 33 of the blade arm 31. In addition, the drive pin 65 of the blade drive lever 60 is configured to protrude in the -Z direction through the arc groove 13 of the base plate 10, and this drive pin 65 that protrudes in the -Z direction is fitted snugly into the lever connecting hole 34 of the blade arm 31. As a result, when the blade drive lever 60 rotates around its shaft portion 61, the drive pin 65 moves within the arc groove 13 of the base plate 10, and the blade arm 31 rotates around the circular hole 33 (the shaft portion 61 of the blade drive lever 60). Furthermore, the arm portion 64 of the blade drive lever 60 is capable of contacting the ends on both sides of the arc groove 13 of the base plate 10.

[0022] Figure 6 is a front view of the link member 70. As shown in Figure 6, a circular hole 71 is formed at one end of the link member 70, and an elongated hole 72 is formed at the other end. As shown in Figure 2, a pin 75 is inserted through the circular hole 71 of the link member 70, and this pin 75 is press-fitted into a circular hole 57 (see Figures 4A and 4B) formed at the tip of the arm portion 53 of the rotary drive member 50. As a result, the rotary drive member 50 and the link member 70 are rotatably connected to each other around the pin 75.

[0023] Furthermore, a pin 76 is inserted into a circular hole 67 (see Figures 5A and 5B) formed in the arm portion 62 of the blade drive lever 60, and this pin 76 protrudes from the blade drive lever 60 in the -Z direction. The pin 76 protruding from the blade drive lever 60 in the -Z direction is inserted into an elongated hole 72 of the link member 70, and is able to move within the elongated hole 72. In this way, the blade drive lever 60 and the link member 70 are connected via the pin 76.

[0024] Returning to Figure 2, a braking member 90 that can rotate around the shaft portion 17 is positioned on the shaft portion 17 of the base plate 10. A brake pad 100 (sliding contact member) is positioned adjacent to the braking member 90. The base plate 10 has a spring receiving portion 14 on the +Y direction side of the brake pad 100, and a coil spring 19 (biasing member) is loaded in a compressed state between this spring receiving portion 14 and the brake pad 100. The biasing force of this coil spring 19 presses the brake pad 100 toward the braking member 90.

[0025] Figure 7 is a perspective view of the braking member 90. As shown in Figure 7, the braking member 90 has a ring portion 92 into which an elliptical hole 91 into which the shaft portion 17 of the base plate 10 is inserted, a stopper piece 93 extending outward from the ring portion 92, and a brake piece 94 having a greater thickness in the Z direction than the ring portion 92. The outer circumferential surface 94A of the brake piece 94 is formed from a part of a cylindrical surface. One side portion 95 of the brake piece 94 is capable of contacting the pusher 54 (first pusher) of the rotary drive member 50, and the other side portion 96 is capable of contacting the pusher 55 (second pusher) of the rotary drive member 50.

[0026] Figure 8 is a perspective view of the brake pad 100. As shown in Figure 8, the brake pad 100 has a pad body 101 having a sliding contact surface 101A that slides against the outer circumferential surface 94A of the brake piece 94 of the braking member 90, and a spring receiving portion 102 that receives the coil spring 19. The sliding contact surface 101A is made up of a part of a cylindrical surface having the same diameter as the cylindrical surface that constitutes the outer circumferential surface 94A of the brake piece 94.

[0027] It is preferable that the braking member 90 and the brake pad 100 are formed from a combination of materials that easily generate frictional force when they come into contact. For example, one of the braking member 90 and the brake pad 100 can be made of acetal and the other of nylon.

[0028] The blades 21-24 are movable between a position that closes the opening S of the base plate 10 (hereinafter referred to as the "closed position") as shown in Figure 9A and a position that opens the opening S of the base plate 10 (hereinafter referred to as the "open position") as shown in Figure 9B. Generally, the operation of the blade drive device in a camera can be divided into two types: normally closed operation, in which the blades are initially in a state where the exposure aperture is closed, and the blades immediately start operating from the initial state when the release button is pressed for shooting; and normally open operation, in which the blades are initially in a state where the exposure aperture is open, and the blades only start operating after the release button is pressed, at the final stage of shooting. The blade drive device 1 in this embodiment can handle either operation, but here we will describe the case where normally closed operation is performed.

[0029] In the normally closed operation, when the release button (not shown) is pressed, the blades 21-24 move from the closed position shown in Figure 9A to the open position shown in Figure 9B. In the state shown in Figure 9A, the blade drive lever 60 is in the position rotated to its maximum extent counterclockwise, and the arm portion 64 of the blade drive lever 60 is in contact with the +Y direction end of the arc groove 13 of the base plate 10. At this time, the coil 84 of the electromagnetic coil unit 80 is not energized, but a clockwise rotational force acts on the rotor 52 of the rotary drive member 50 due to the magnetic attraction and repulsion forces generated between the two magnetic poles 52A, 52B of the rotor 52 of the rotary drive member 50 and the magnetic poles formed by the four yokes 81A, 81B, 82A, 82B. As a result, a counterclockwise rotational force is generated on the blade drive lever 60 via the link member 70, and the blade drive lever 60 is held in the position shown in Figure 9A. The position of the rotational drive member 50 at this time will be referred to as the "first rotational position".

[0030] When the photographer presses the release button in the state shown in Figure 9A, the coil 84 is energized, generating, for example, north poles on yokes 81A and 81B and south poles on yokes 82A and 82B. This change in magnetic poles generates a counterclockwise rotational force on the rotor 52 of the rotary drive member 50, causing the rotary drive member 50 to rotate counterclockwise around the drive shaft 18. Consequently, the blade drive lever 60 rotates clockwise via the link member 70 connected to the arm portion 53 of the rotary drive member 50. When the blade drive lever 60 rotates clockwise, the blade arm 31 rotates clockwise by the drive pin 65 of the blade drive lever 60, and the blades 21 to 24 move in the -Y direction by the link mechanism described above. Finally, the arm portion 64 of the blade drive lever 60 comes into contact with the -Y direction end of the arc groove 13 of the base plate 10, stopping the blade drive lever 60, and the blades 21-24 move to the open position (Figure 9B) that opens the opening S of the base plate 10.

[0031] In the state shown in Figure 9B, a counterclockwise rotational force acts on the rotor 52 of the rotary drive member 50 due to the magnetic attraction and repulsion forces generated between the two magnetic poles 52A and 52B of the rotor 52 of the rotary drive member 50 and the magnetic poles formed by the four yokes 81A, 81B, 82A, and 82B. Therefore, even if the power supply to the coil 84 is stopped after the blades 21-24 have moved to the open position shown in Figure 9B, a clockwise rotational force is generated in the blade drive lever 60 via the link member 70, and the blade drive lever 60 is held in the position shown in Figure 9B. The position of the rotary drive member 50 at this time will be referred to as the "second rotational position".

[0032] As described above, when the vanes 21-24 move from the closed position shown in Figure 9A to the open position shown in Figure 9B, the rotary drive member 50 rotates counterclockwise from the first rotation position to the second rotation position (opening operation). However, just before the rotary drive member 50 reaches the second rotation position, as shown in Figure 10A, the pusher 54 of the rotary drive member 50 comes into contact with the side portion 95 of the brake piece 94 of the braking member 90. If the rotary drive member 50 rotates further counterclockwise from this state, the pusher 54 will push the brake piece 94 of the braking member 90 counterclockwise. Since the brake pad 100 is pressed toward the brake piece 94 of the braking member 90 by the coil spring 19, a frictional force is generated due to sliding contact between the outer circumferential surface 94A of the brake piece 94 of the braking member 90 and the sliding contact surface 101A of the brake pad 100, which slows down the rotation of the braking member 90, and consequently the rotation of the rotary drive member 50. This reduces the speed of the blades 21-24 just before they stop, and suppresses the rebound of the blades 21-24 when they stop. The rotational drive member 50 eventually rotates until the arm 64 of the blade drive lever 60 contacts the -Y direction end of the arc groove 13 of the base plate 10 as described above, reaching the second rotational position shown in Figure 10B. The position of the braking member 90 at this time is referred to as the "first standby position".

[0033] As described above, after the blades 21-24 move to the open position shown in Figure 9B, the charge accumulated in the image sensor is released, and the accumulation of charge for imaging begins. After a predetermined time has elapsed, a signal from the control circuit causes a current in the opposite direction to the current previously flowed through the coil 84, so that, for example, south poles are generated in the yokes 81A and 81B, and north poles are generated in the yokes 82A and 82B. This change in magnetic poles generates a clockwise rotational force in the rotor 52 of the rotary drive member 50, causing the rotary drive member 50 to rotate clockwise around the drive shaft 18. Accordingly, the blade drive lever 60 rotates counterclockwise via the link member 70 connected to the arm portion 53 of the rotary drive member 50. When the blade drive lever 60 rotates counterclockwise, the drive pin 65 of the blade drive lever 60 causes the blade arm 31 to rotate counterclockwise, and the blades 21-24 move in the +Y direction by the link mechanism described above. Finally, the arm portion 64 of the blade drive lever 60 comes into contact with the +Y direction end of the arc groove 13 of the base plate 10, stopping the blade drive lever 60, and the blades 21-24 move to the closed position (Figure 9A) that closes the opening S of the base plate 10.

[0034] As described above, when the vanes 21-24 move from the open position shown in Figure 9B to the closed position shown in Figure 9A, the rotary drive member 50 rotates clockwise from the second rotation position to the first rotation position (closing operation). However, just before the rotary drive member 50 reaches the first rotation position, as shown in Figure 10C, the pusher 55 of the rotary drive member 50 comes into contact with the side portion 96 of the brake piece 94 of the braking member 90 (which is located in the first standby position). If the rotary drive member 50 rotates further clockwise from this state, the pusher 55 will push the brake piece 94 of the braking member 90 clockwise. Since the brake pad 100 is pressed toward the brake piece 94 of the braking member 90 by the coil spring 19, a frictional force is generated between the outer peripheral surface 94A of the brake piece 94 of the braking member 90 and the sliding contact surface 101A of the brake pad 100, which slows down the rotation of the braking member 90 and, consequently, the rotation of the rotary drive member 50. This reduces the speed of the blades 21-24 just before they stop, and suppresses the rebound of the blades 21-24 when they stop. The rotary drive member 50 eventually rotates until the arm portion 64 of the blade drive lever 60 contacts the +Y direction end of the arc groove 13 of the base plate 10 as described above, reaching the first rotation position shown in Figure 10D. The position of the braking member 90 at this time is referred to as the "second standby position". In the opening operation of the rotary drive member 50 described above, the pusher 54 of the rotary drive member 50 comes into contact with the side portion 95 of the brake piece 94 of the braking member 90, which is located in this second standby position (see Figure 10A).

[0035] Thus, in this embodiment, the pushers 54 and 55 of the rotary drive member 50 function as contact parts configured to contact the brake piece 94 of the braking member 90 and push the braking member 90 before the end of the opening operation and before the end of the closing operation. In this way, because the pushers 54 and 55, as contact parts, contact the brake piece 94 of the braking member 90 and push the braking member 90 before the end of the opening operation and before the end of the closing operation of the rotary drive member 50, a frictional force is generated by sliding contact between the outer peripheral surface 94A of the brake piece 94 of the braking member 90 and the sliding contact surface 101A of the brake pad 100, thereby decelerating the rotation of the braking member 90 and, consequently, the rotation of the rotary drive member 50. As a result, the speed of the blades 21 to 24 before they stop can be reduced, and the rebound of the blades 21 to 24 when they stop can be suppressed. Furthermore, since the braking member 90 and the brake pad 100 slide against each other on the radially outer side of the rotational drive member 50, it is possible to avoid the vane drive device 1 becoming thicker in the direction along the drive shaft 18.

[0036] Furthermore, in this embodiment, the pusher 55 can move the braking member 90 to a position where the pusher 54 of the rotary drive member 50 can make contact (first standby position), and the pusher 54 can move the braking member 90 to a position where the pusher 55 of the rotary drive member 50 can make contact (second standby position). Therefore, it is possible to reduce the speed of the blades 21-24 both before the end of the opening operation and before the end of the closing operation.

[0037] Here, as shown in Figure 2, the base plate 10 has restricting protrusions 15, 16 (restricting parts) that project in the +Z direction. These restricting protrusions 15, 16 are positioned adjacent to the stopper piece 93 of the braking member 90 in the circumferential direction and are capable of engaging with the stopper piece 93 of the braking member 90. As shown in Figure 10D, the restricting protrusion 15 restricts the clockwise rotation of the braking member 90, and as shown in Figure 10B, the restricting protrusion 16 is configured to restrict the counterclockwise rotation of the braking member 90, thus defining the rotation range of the braking member 90. In this way, the restricting protrusions 15, 16 of the base plate 10 can define the range in which the braking member 90 can rotate, and malfunctions caused by the braking member 90 moving to an unintended position can be prevented.

[0038] In this embodiment, the elliptical hole 91 of the braking member 90 is larger than the outer diameter of the shaft portion 17 of the base plate 10 in order to allow the braking member 90 to be attached to the shaft portion 17 of the base plate 10. However, after the braking member 90 is attached to the shaft portion 17 of the base plate 10, the braking member 90 is pushed in the -Y direction by the coil spring 19, so that the claw portion 17A provided on the shaft portion 17 of the base plate 10 engages with the ring portion 92 of the braking member 90. Therefore, the braking member 90 is less likely to come off the shaft portion 17 of the base plate 10.

[0039] In this embodiment, the braking member 90 is configured to rotate around the shaft portion 17 of the base plate 10 and to rotate around the same axis as the rotation drive member 50. However, the braking member 90 does not need to be positioned coaxially with the rotation drive member 50, and it does not necessarily need to rotate around the axis as long as it is movable in the vicinity of the rotation drive member 50.

[0040] Furthermore, in this embodiment, a blade drive lever 60 and a link member 70 are interposed between the rotary drive member 50 and the blade arm 31, but the rotary drive member 50 may be directly connected to the blade arm 31.

[0041] In this embodiment, the rotary drive member 50 is driven by an electromagnetic coil unit 80, but the method of driving the rotary drive member 50 is not limited to electromagnetic means, and the rotary drive member 50 may be configured to be driven using a biasing means such as a spring.

[0042] In this embodiment, the coil spring 19 presses the brake pad 100 against the outer circumferential surface 94A of the brake piece 94 of the braking member 90. However, as shown in Figure 11, for example, a leaf spring 220 may be placed in a bent state between the spring receiver 210 of the base plate 10 and the brake piece 94 of the braking member 90, and the sliding contact surface 220A of the leaf spring 220 may be biased toward the outer circumferential surface 94A of the brake piece 94 of the braking member 90. In this case, the spring receiver 14, coil spring 19, and brake pad 100 shown in Figure 2 can be omitted. It is preferable that the leaf spring 220 is made of a material that easily generates frictional force when the braking member 90 slides against it.

[0043] As described above, according to the first aspect of the present invention, a blade drive device is provided that can suppress the rebound of the blades when they stop while avoiding increasing thickness in the direction along the drive shaft. Specifically, the blade drive device according to the present invention can employ the following configuration.

[0044] (Composition 1) The blade drive device comprises a base plate having an opening formed therein, at least one blade movable between a closed position that closes the opening and an open position that opens the opening, a rotary drive member directly or indirectly connected to the at least one blade and capable of moving the at least one blade from the closed position to the open position by rotating from a first rotation position to a second rotation position about a drive shaft, and moving the at least one blade from the open position to the closed position by rotating from the second rotation position to the first rotation position, a braking member configured to be movable in the vicinity of the rotary drive member, and a sliding contact member that slides against the outer circumferential surface of the braking member and suppresses the movement of the braking member by friction. The rotary drive member has a contact portion configured to contact the braking member and push the braking member before the completion of at least one of the operations: an opening operation in which it rotates from the first rotation position to the second rotation position and a closing operation in which it rotates from the second rotation position to the first rotation position.

[0045] With this configuration, the contact portion of the rotary drive member contacts the braking member and pushes the braking member before the completion of at least one of the opening and closing operations of the rotary drive member. This generates a frictional force due to sliding between the outer surface of the braking member and the sliding contact member, which slows down the rotation of the braking member and, consequently, the rotation of the rotary drive member. As a result, the speed before the blades stop can be reduced, and rebound when the blades stop can be suppressed. Furthermore, since the braking member and the sliding contact member slide against each other on the radially outer side of the rotary drive member, it is possible to avoid increasing the thickness of the blade drive device in the direction along the drive shaft.

[0046] (Configuration 2) In the above configuration 1, it is preferable that the contact portion of the rotary drive member includes a first pusher that pushes the braking member in a first direction before the opening operation is completed, and a second pusher that pushes the braking member in a second direction opposite to the first direction before the closing operation is completed. These pushers can decelerate the rotation of the rotary drive member both before the opening operation and before the closing operation is completed.

[0047] (Composition 3) In the above configuration 2, the first pusher of the rotary drive member may be configured to move the braking member to a first standby position at the end of the opening operation, and the second pusher of the rotary drive member may be configured to contact the braking member located at the first standby position before the end of the closing operation. With such a configuration, the first pusher of the rotary drive member can move the braking member to a position (first standby position) that can be contacted by the second pusher of the rotary drive member.

[0048] (Composition 4) In the above configuration 2 or 3, the second pusher of the rotary drive member may be configured to move the braking member to a second standby position at the end of the closing operation, and the first pusher of the rotary drive member may be configured to contact the braking member located at the second standby position before the end of the opening operation. With such a configuration, the braking member can be moved by the second pusher of the rotary drive member to a position (second standby position) that can be contacted by the first pusher of the rotary drive member.

[0049] (Composition 5) In any of the above configurations 1 to 4, it is preferable that the base plate has a restricting portion that defines the range of movement of the braking member, and the braking member has a stopper piece that can engage with the restricting portion of the base plate. With such a configuration, the restricting portion of the base plate can define the range in which the braking member can move, and malfunctions caused by the braking member moving to an unintended position can be prevented.

[0050] (Composition 6) In any of the above configurations 1 to 5, the blade drive device may further include a biasing member that presses the sliding contact member against the outer circumferential surface of the braking member.

[0051] (Composition 7) In any of the above configurations 1 to 5, the sliding contact member may be composed of a spring member biased toward the outer circumferential surface of the braking member.

[0052] According to a second aspect of the present invention, an imaging device is provided comprising a blade drive device described in any one of the above configurations 1 to 7, and an image sensor arranged on a surface where light transmitted through the blade drive device forms an image.

[0053] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the embodiments described above and may be implemented in various different forms within the scope of its technical concept. [Explanation of Symbols]

[0054] 1. Blade drive mechanism 10 Main plate 13 Arc groove 14 Spring support 15,16 Regulating protrusion (regulating part) 17. Shaft section 18 drive shafts 19. Coil spring (biasing member) 21-24 feathers 31,32 Feather Arm 50 Rotary drive member 51 Shaft 52 rotors 53 Arm 54 (First) Pusher 55 (Second) Pusher 60-blade drive lever 61 Shaft 62~64 Arm 65 drive pins 70 Link members 80 Electromagnetic Coil Unit 81A, 81B, 82A, 82B York 83A, 83B bobbins 84 coils 90 Braking member 93 Stopper piece 94 Brake fragments 94A Outer surface 100 Brake pads (sliding contact members) 220 leaf spring S opening

Claims

1. A floorboard with an opening formed therein, At least one vane that is movable between a closed position that closes the opening and an open position that opens the opening, A rotary drive member directly or indirectly connected to the at least one blade, which can rotate from a first rotation position to a second rotation position about a drive shaft to move the at least one blade from the closed position to the open position, and rotate from the second rotation position to the first rotation position to move the at least one blade from the open position to the closed position, A braking member configured to be rotatable around the drive shaft, A sliding contact member that contacts the outer circumferential surface of the braking member in a radial direction centered on the drive shaft and suppresses the rotation of the braking member by friction, Equipped with, The rotational drive member has a contact portion configured to contact the braking member in the circumferential direction around the drive shaft and push the braking member in the circumferential direction before the completion of at least one of the operations: an opening operation in which it rotates from the first rotational position to the second rotational position and a closing operation in which it rotates from the second rotational position to the first rotational position. The braking member has a brake piece, The radial outer surface of the brake piece is the outer circumferential surface, The aforementioned brake piece is The first side portion on one side in the circumferential direction, The second side portion on the other side in the circumferential direction, It has, The contact portion of the rotational drive member includes a first pusher and a second pusher arranged to sandwich the brake piece in the circumferential direction. The first pusher contacts the first side before the opening operation is completed and pushes the braking member to the other side in the circumferential direction. The vane drive device wherein the second pusher contacts the second side before the closing operation is completed and pushes the braking member to one side in the circumferential direction.

2. The first pusher of the rotational drive member is configured to move the braking member to a first standby position when the opening operation is completed. The vane drive device according to claim 1, wherein the second pusher of the rotary drive member is configured to contact the braking member located in the first standby position before the closing operation is completed.

3. The second pusher of the rotational drive member is configured to move the braking member to the second standby position when the closing operation is completed. The vane drive device according to claim 1, wherein the first pusher of the rotary drive member is configured to contact the braking member located in the second standby position before the opening operation is completed.

4. The base plate has a restricting portion that defines the range of movement of the braking member, The vane drive device according to any one of claims 1 to 3, wherein the braking member has a stopper piece that can engage with the restricting portion of the base plate.

5. The vane drive device according to any one of claims 1 to 3, further comprising a biasing member that presses the sliding contact member against the outer circumferential surface of the braking member.

6. The blade drive device according to any one of claims 1 to 3, wherein the sliding contact member is composed of a spring member biased toward the outer circumferential surface of the braking member.

7. A blade drive device according to any one of claims 1 to 3, An image sensor is positioned on the plane where light transmitted through the aforementioned vane drive device forms an image, An imaging device equipped with the following features.

Images