JPH0728123A - Photo-quantity control device - Google Patents

Abstract

PURPOSE:To provide possibility of installing component parts from one side to a stop bottom plate and reduce the man-hours and the costs by furnishing a bearing on each of the stop bottom plate and a stop cover, and fitting the two ends of the shaft of a drive arm in the bearings. CONSTITUTION:Stop blades 10, 11 are accommodated in a recess provided in a stop bottom plate 1, and the place is covered with a stop cover 13, and the blades 10, 11 are driven by a drive arm 8 which is rotated by a servo motor so as to vary the photo-quantity passing through apertures of the plate 1 and cover 13. In this photo-quantity control device, bearings 1a, 13a are furnished on the plate 1 and cover 13, respectively, and the two ends of the shaft of the drive arm 8 are fitted in these bearings. This enables assembling in cast-in system from above using the stop bottom plate 1 as the reference, and a consistent automated assembly can be conducted. Also it is possible to consolidate the shaft with the drive arm 8 and to eliminate use of any cap for bearing the drive arm shaft and a fixing screw therefore to lead to reduction of component parts used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light amount control device for a camera or the like, and more particularly to a light amount control device which is excellent in productivity and is suitable for a video camera having a reliable operation.

[0002]

2. Description of the Related Art An example of a conventional light quantity control device is shown in FIG. In the figure, 1 is a diaphragm base plate, 2 is a yoke, 3A,
3B is a coil portion, 4 is a flexible printed wiring board, 5
Is a Hall element, 6 is an insulating tape, 7 is a magnet, 8 is a drive arm, 10 and 11 are diaphragm blades, 12 is an ND filter, 13 is a diaphragm cover, 14 is a cap, and 15 is a shaft.

Assembling of the light quantity control device composed of the above-mentioned members is generally performed as follows. That is,
The upper portion of the shaft 15 to which the magnet 7 is fixed is inserted into the upper bearing 1a provided on the throttle base plate 1, and the drive arm 3 is press-fitted or adhered to the upper end portion of the shaft. Then, the return spring 9 is attached to the drive arm 8, the diaphragm blades 10 and 11 are attached, and the diaphragm cover 13 shields it.

In the lower part of the main plate, coils 3A and 3B, an insulating tape 6 and a yoke 2 are provided around the magnet 7.
, The lower end of the shaft 15 is inserted into the lower bearing 14a provided on the cap 14, and the cap 14 is fixed to the throttle base plate 1 with screws 16.

[0005]

In the conventional example, the assembly as described above with reference to FIG. 2 is performed. Therefore, there are drawbacks as described below.

(1) Since various parts are assembled from above and below the drawing base plate 1, it is difficult to automate the production. (2) A member constituting the bearing, that is, a cap is required separately.
(3) Since one bearing is free from the other bearing, the shaft tilts, the operation becomes inaccurate, and the shaft loss occurs. (4) The drive arm and the shaft must be separate members. As a result, the cost of the parts will increase and the number of assembling steps will increase. (5) Props and screws for fixing the meter section are required. (6) The yoke of the outer peripheral member of the meter section shines with a lens. Is reflected and problems such as ghosts occur. The present invention aims to solve the above problems.

[0007]

The light quantity control device according to the present invention comprises: (1) A diaphragm blade is housed in a recess of the diaphragm base plate and covered with a diaphragm cover, and the diaphragm is rotated by a drive arm rotated by a servomotor. In a light amount control device that drives blades and makes the amount of light passing through each aperture diameter of the aperture base plate and aperture cover variable, a bearing is provided on each of the aperture base plate and the aperture cover, and both ends of the shaft of the drive arm are It is characterized in that a fitting shaft is supported by each bearing, and (2) in (1), the servo motor is enclosed by a diaphragm base plate. By such means, diaphragm blades, drive arms, It is possible to install the servo motor etc. from one direction with respect to the drawing base plate, reducing the number of assembly steps and parts cost, space saving, and weight reduction. Improvement in improving the working characteristics of the biological performance can be realized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a drawing that best represents the features of the present invention. In the figure, 1 is a drawing base plate, 1a is a lower bearing, 1b is a clearance hole for terminal pins of coils 3A and 3B described later, 1c is a positioning hole, 1d is a hook for positioning or fixing the coils 3A and 3B, and 1e is a guide. Alternatively, a positioning pin, 1f is a positioning dowel, 1g, 1h, 1j, 1k is a guide pin, 1i is a hook claw, 1l is a hole, 1m is a diaphragm aperture, 1n is a recess for accommodating diaphragm blades, 1p is a servomotor or a yoke. Is a recess for accommodating the above, and these elements 1a to 1p are provided in the drawing base plate 1. Squeezed ground plate 1
The diaphragm cover 13 is preferably made of anodized aluminum, carbon fiber reinforced plastic, or the like. 2 is a yoke having a recess 2a, 3 is 3
A, 3B are coils, 3Aa, 3Ab, 3Ba, 3Bb are provided on the coils 3A, 3B, respectively, and projections that fit into the positioning holes 1c of the diaphragm base plate, 4 are flexible printed wiring boards, 5 are Hall elements, and 6 are Insulation tape, 7 is hole 7a
It is a magnet having. Reference numeral 8 denotes a drive arm with a shaft, which is composed of an arm portion 8-1 and a shaft portion 8-2. The shaft portion 8a is fitted with the bearing 1a and the hole 7 of the magnet 7 is provided.
a shaft portion 8b press-fitted into a, a shaft portion 8c around which the return spring 9 is wound, a collar portion 8d for pressing the return spring 9,
It has a shaft portion 8e that fits with an upper bearing 13a described later, drive pins 8f and 8g, and a locking pin 8h. Reference numeral 9 is a return spring, and 10 and 11 are diaphragm blades. The blade 10 has a drive elongated hole 10a and guide elongated holes 10b and 10c. Hole 11
b and 11c. Reference numeral 12 is an ND filter. Reference numeral 13 is a diaphragm cover, which is hooked by the upper bearing 13a, the convex portion 13b for protecting the shaft portion, and the claw 1i.
It has a hole 13c, a positioning hole 13d, and a diaphragm aperture 13e provided at various locations.

A light quantity control device according to an embodiment of the present invention is
It is composed of each member as described above, and these members are assembled as follows.

The fixed portion 8b of the drive arm 8 around which the return spring 9 is wound is press-fitted or adhered and fixed to the hole 7a of the magnet 7, the magnet is sandwiched by the coils 3A and 3B, and the hall element 5 is soldered or the like. The fixed flexible printed wiring board 4 is adhered to one of the coils 3A or 3B with an adhesive or a double-sided tape, and fixed with an insulating tape 6 so that no gap can be formed between the bobbins. In this case, the outer diameter of the tape is dimensioned so that no gap is formed between it and the inner diameter of the yoke 2. Next, the yoke 2 is inserted into the recess of the drawing base plate, and the claw 1d of the drawing base plate 1 is inserted into the recess 2a of the yoke.
To fix and position. In this case, the bearing 1a has a mortar shape, and the tip of the shaft is smoothly guided to the bearing 1a. Further, as described above, the servo motor is formed mainly by the yoke, the coil, and the magnet.

The flexible printed wiring board 4 has a hole 1l.
Each of the holes 1c is protruded from each of the protrusions 3 of the coils 3A and 3B.
Position the coil by engaging Aa and 3Ba and 3Ab and 3Bb. The dowel 1f engages with the hole 2a of the yoke 2 for positioning. As described above, the meter portion is the diaphragm base plate 1
Fixed to. Next, one end of the return spring 9 is locked to the locking pin 8h of the drive arm 8 and the other end is locked to the locking portion (not shown) of the diaphragm base plate 1, whereby the drive arm 8 is automatically closed. I will take a posture. Next, the guide pins 1g, 1h, 1j, and 1k of the diaphragm base plate 1 are inserted into the elongated guide blades 10b, 10c, 11b, and 11c of the diaphragm blade 10 to which the ND filter is adhered, respectively. Drive slots 10a and 11 of the blades 10 and 11
Insert the drive pins 8f and 8g of the drive arm 8 into a,
The diaphragm blades 10 and 11 are housed in the recesses of the diaphragm base plate 1.

Finally, the fitting shaft portion 8e of the drive arm 8 is fitted to the bearing 13a of the diaphragm cover 13, and the diaphragm cover 1
Insert pin 1e of diaphragm base plate 1 into hole 13d of hole 3
C is hook-engaged with the hook claw 1i to fix the diaphragm base plate 1 and the diaphragm cover 13 to each other. In this case, the tip of the shaft portion 8e is largely chamfered or rounded to facilitate insertion, and is protected by the convex portion 13b.

The embodiment of the present invention is constructed and assembled as described above, and it is possible to perform the assembling by the throwing-in method from above with reference to the drawing base plate, and the consistent automatic assembly is possible. In addition, the shaft and the drive arm can be integrated, the cap that pivotally supports the shaft of the drive arm and the fixing screw of the cap can be removed, and the number of parts can be reduced, the manufacturing cost can be reduced, and the weight and space can be saved. Is possible. Further, by covering the yoke of the servomotor completely with the diaphragm base plate made of the antireflection color (material), it is possible to prevent optical image disturbance such as ghost and flare. Further, since the cores of the upper and lower bearings are easily aligned by positioning the members constituting the bearings with each other, it is possible to reduce the axial loss and to stabilize and improve the operating performance.

[0014]

As described above, in the light quantity control device of the present invention, the bearings for rotatably supporting the shafts of the drive arms for driving the diaphragm blades are provided on the diaphragm base plate and the diaphragm cover, respectively. In addition, the number of assembling steps can be reduced, the space can be saved, and the weight can be reduced, so that the manufacturing cost can be reduced. Further, by positioning the members forming the bearings with respect to each other, the center of the upper and lower bearings can be easily taken out, the axial loss can be reduced, and the operation characteristics can be stabilized and improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a configuration of a light amount control device embodying the present invention.

FIG. 2 is a configuration diagram showing an example of a conventional light amount control device.

[Explanation of symbols]

1 ... Drawing base plate, 2 ... Yoke, 3 ... Coil, 4 ... Flexible printed wiring board 5 ... Hall element, 6 insulating tape, 7 ... Magnet, 8 ...
Drive arm, 9 ... Return spring, 10, 11 ... Aperture blade, 12 ... ND filter, 13 ... Aperture cover

Claims (2)

[Claims] 1. A diaphragm blade is housed in a recess of a diaphragm base plate and covered with a diaphragm cover, and the diaphragm blade is driven by a drive arm rotated by a servomotor, and passes through each diaphragm aperture of the diaphragm base plate and the diaphragm cover. In a light quantity control device for varying the light quantity, a bearing is provided on each of the diaphragm base plate and the diaphragm cover, and both ends of the shaft of the drive arm are fitted and supported by the bearings. 2. The light quantity control device according to claim 1, wherein the servo motor is enclosed by a diaphragm base plate.