JPH0728124A - Photo-quantity control device - Google Patents

Abstract

PURPOSE:To reduce the man-hours and the cost for component parts and accomplish a stabilized and enhanced rolling strength by structuring an arm part and a shaft part to support it in a single piece construction, and thereby forming a drive arm. CONSTITUTION:A shaft-equipped drive arm 8 is composed of an arm part 8-1 and shaft part 8-2 and yielded through single piece shaping of the two parts. It is preferable that the drive arm 8 is made through injection molding from a hard nature engineering plastic, but any other known method for shaping may be accepted. The shaft part 8-2 has a spring winding part 8c on which a return spring is wound, while the arm part 8-1 has drive pins 8f, 8g engaged by stop blades and transmitting the driving force. Constituting the driving arm 8 in a single piece structure as described enables reducing the number of component parts and/or man-hours in assembly to lead to reduction of the manufacturing costs, and also the strength of the shaft-equipped drive arm is heightened and the operation as photo-quantity control device is stabilized.

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 suitable for a video camera which is excellent in productivity and has improved strength.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional light amount control device. 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, the coils 3A and 3B, the insulating tape 6, and the yoke 2 are arranged around the magnet 7.
The lower end of the shaft 15 is inserted into a lower bearing 14 a provided on the cap 14, and the cap 14 is fixed to the throttle base plate 1 with screws 16.

Therefore, the drive arm 8 and the shaft 15 are
It is a structure that cannot be assembled unless the two are separated, and one end of the shaft was finally inserted into the hole of the drive arm and fixed by press fitting or adhesion.

[0005]

In the conventional example, the assembly as described above with reference to FIG. 3 is performed. Therefore, since the drive arm 8 and the shaft 15 are separate members, there are drawbacks as described below.

(1) The step of connecting the two members of the drive arm and the shaft is required, which increases the number of assembling steps.
(2) At least the above-mentioned 2 members are required, and the cost of parts is high. (3) For the connection of the above 2 members, the shaft tip is knurled, press fit into the hole of the drive arm, and the strength is controlled by the press fit. Therefore, it is necessary to control the fixed strength (rolling strength) of the two members. The present invention aims to solve the above problems.

[0007]

In the light quantity control device according to the present invention, 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. In the light amount control device for changing the amount of light passing through each aperture diameter of the diaphragm base plate and the diaphragm cover, a drive pin for transmitting a driving force to the diaphragm blade and a spring latch for locking a return spring of the drive arm. A drive arm is formed by integrally forming an arm portion having a pin and a shaft receiving portion that engages with a bearing at both ends, and a shaft portion that supports the arm portion. Realizes reduction of assembly man-hours and parts cost, and enables stable and improved rolling strength.

[0008]

1 and 2 are drawings which best show the features of the present invention. In FIG. 1 and FIG. 2, 1 is a drawing base plate,
1a is a lower bearing, 1b is a clearance hole for a terminal pin of coils 3A and 3B described later, 1c is a positioning hole, 1d is a coil 3
A hook for positioning or fixing A, 3B, 1e is a guide or a positioning pin, 1f is a positioning dowel, 1g, 1h,
1j, 1k are guide pins, 1i are hook claws, 1l are holes,
1m is a diaphragm aperture, 1n is a recess for accommodating diaphragm blades, 1p
Is a recess that houses the servomotor or yoke,
These elements 1 a to 1 p are provided on the drawing base plate 1. The drawn base plate 1 and the drawn cover 13 are preferably made of anodized aluminum, carbon fiber reinforced plastic, or the like. Reference numeral 2 is a yoke having a concave portion 2a, 3 is 3A, 3B is a coil, 3Aa, 3Ab, 3B
a, 3Bb are provided on the coils 3A, 3B, respectively, and the protrusions fit into the positioning holes 1c of the drawn base plate, 4 is a flexible printed wiring board, 5 is a hall element, 6 is an insulating tape, and 7 is a magnet having a hole 7a. Is.

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, and is manufactured by integrally molding these both. The drive arm 8 is preferably made of hard engineering plastic and integrally formed by injection molding, but may be formed by other known forming means. The shaft portion 8-2 includes a bearing portion 8a that fits with the bearing 1a, a fitting portion 8b that is fitted into the hole 7a of the magnet 7 and press-fitted or bonded, and a spring winding portion that winds the return spring 9. 8c, a collar portion 8d that presses the return spring 9, a bearing portion 8e that fits with an upper bearing 13a described later, and a convex portion 8i for press fitting. The arm portion 8-1 includes the diaphragm blade 1 described later.
It has drive pins 8f and 8g that engage with the drive slots 10a and 11a of 0 and 11 to transmit the driving force, and spring retaining pins 8h that retain the return spring 9 described later.

Reference numeral 9 is a return spring, and 10 and 11 are diaphragm blades. The blades 10 are a driving elongated hole 10a and a guiding elongated hole 1.
0b, 10c, and similarly, the blade 11 has a driving slot 11a and guide slots 11b, 11c. 1
2 is an ND filter. A diaphragm cover 13 includes an upper bearing 13a, a convex portion 13b for protecting the shaft portion, and a claw 1i.
It has a hole 13c, a positioning hole 13d, and a diaphragm aperture 13e provided at four places so as to be hooked in.

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 bonded to one of the coils 3A or 3B with an adhesive or a double-sided tape, and is fixed with an insulating tape 6 so that no gap is 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 into 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. By making the shaft part and the arm part of the drive arm the same part, it is possible to reduce the number of parts and the number of assembling steps. Therefore, the manufacturing cost of the light quantity control device can be reduced. Also, the improvement of the rolling strength,
Stabilization is achieved.

[0016]

As described above, in the light quantity control device of the present invention, the arm portion having the spring retaining portion and the shaft portion supporting the arm portion are integrally molded to form the drive arm. It is possible to reduce the number of parts and the number of assembly steps, reduce the manufacturing cost, improve the strength of the drive arm with the shaft, and stabilize the operation as the light amount control device.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example of the configuration of a light quantity control device embodying the present invention.

FIG. 2 is a perspective view of a drive arm in the above embodiment.

FIG. 3 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, 7 ... Magnet, 8 ... Drive arm, 8
-1 ... Arm part, 8-2 ... Shaft part, 8a, 8e ... Bearing receiving part, 8f, 8g ... Drive pin, 8h ... Spring retaining pin, 9 ... Return spring, 10, 11 ... Aperture blade, 13
… Aperture cover

Claims (1)

[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, an arm portion having a drive pin for transmitting a driving force to the diaphragm blade and a spring hooking pin for hooking a return spring of the driving arm, and bearings fitted at both ends. And a shaft portion supporting the arm portion, which is integrally formed with the shaft portion to form a drive arm.