JP2003043552A - Light quantity adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to improve the air gap accuracy of an induction magnetic member and a magnet rotor and a light quantity adjusting device whose excellent performance is maintained by simplifying assemblability by reducing the number of parts. SOLUTION: The inclination of the axial center of the magnet rotor is prevented by a method by which two bearing parts are integrally molded at a base plate and the magnet rotor is fitted in the bearing part having an aperture part by using elastic deformation, and then, the aperture direction of the bearing part is arranged in a direction nearly orthogonal with the magnetic pole direction of two opposed poles of the induction magnetic member, so that the influence of axial backlash due to the aperture part of the bearing part is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light amount adjusting device used in a camera, a video camera or the like.

[0002]

2. Description of the Related Art Conventionally, a so-called outer magnet type electromagnetic actuator, which is constituted by a magnet rotor having a rotating shaft and a pair of magnetizing members opposed to each other with an air gap formed in the magnet rotor, is driven. As a light amount adjusting device used for a camera, a video camera or the like as a light source, there is a light amount adjusting device as proposed in JP-A-7-181551.

[0003]

However, in the light quantity adjusting device proposed in the above publication, the magnetizing member is positioned and fixed to the substrate supporting the light quantity adjusting member.
One of the magnet rotors having a rotating shaft is supported by a bearing portion formed integrally with the substrate, while the other is supported by a bearing portion formed by another member (case in the above publication) attached to the substrate. However, depending on the mounting accuracy of the case, the axial center of the magnet rotor may be tilted, and the air gap accuracy between the magnetizing member and the magnet rotor may not be ensured.

In this case, as shown in FIG. 1, the two bearing portions 2a and 2b are integrally formed on the substrate 1 with synthetic resin or the like, and the shaft portion 4a of the rotor magnet 3 is inserted into the bearing portion 2a and then provided on the bearing portion 2b. A method may be considered in which the shaft portion 4b of the rotor magnet 3 is fitted by utilizing the elastic deformation of the formed opening portion 2c. According to this method, it is possible to eliminate the problem of deterioration in positional accuracy due to the bearing portion being configured and attached to another member, and the number of parts can be reduced and the assemblability can be facilitated.

However, in this method, if the opening width A of the slit-shaped opening 2c that elastically deforms is not set to have a sufficient margin within the elastic deformation limit of the synthetic resin, the bearing portion is plastically deformed and the bearing hole diameter 2e becomes large. There is a risk of damage to the bearing and damage to the bearing itself.

For this reason, there is a method in which a slit like 2d is provided on the opposite side of the slit-shaped opening 2c of the bearing to increase the amount of elastic deformation, but if the slit 2d is lengthened, the effect is great, but a synthetic resin mold is used. The influence of deformation during molding becomes large, and the dimensional accuracy of the bearing hole diameter 2e decreases,
There is a limit to how long it can be.

Further, the synthetic resin material used for the substrate is required to have strength from the function of holding the light quantity adjusting blade, the magnetizing member, the magnet rotor, etc. Generally, the elastic deformation amount is small. is there.

Therefore, the dimension of the opening width A is the bearing hole diameter 2
The size must be set to at least about 80% with respect to e. In this case, as shown in (a) and (b) of FIG. 2 which is an enlarged view of the bearing portion 2b, the fitting clearance between the shaft and the bearing is There was a problem that the fitting clearance E in the direction B was larger than the fitting clearance D in the direction C. In FIG. 2, the shaft portion 4b is illustrated to be smaller than the actual size for the sake of explanation, and the clearance amount is illustrated to be easy to understand. This is because it will stick out.

This increase in the clearance amount affects the air gap distance between the magnet attracting member and the magnet rotor, and the air gap distance cannot be set small, which causes a reduction in the magnetic circuit permeance of the electromagnetic actuator. As a result, performance of the light amount adjusting device itself, such as shutter speed and power consumption, may be degraded.

Therefore, the present invention provides a method for improving the air gap accuracy between the magnetizing member and the magnet rotor,
It is an object of the present invention to provide a light quantity adjusting device that reduces the number of parts, facilitates assembly, and maintains high performance.

[0011]

In order to achieve the above-mentioned object, in the present invention, a substrate having an optical axis opening, a light quantity adjusting blade arranged in the optical axis opening, and a light quantity adjusting blade connected to the light quantity adjusting blade. In a light quantity adjusting device including a magnet rotor having a rotating shaft at the center, a pair of magnetizing members opposed to each other by forming an air gap in the magnet rotor, and a coil for generating magnetic poles in the magnetizing member. ,
While integrally molding a pair of bearing portions having bearing holes for fitting and supporting the rotation shaft of the magnet rotor,
At least one of the bearing portions is provided with a slit-shaped opening which is continuous with the bearing hole and into which the rotary shaft is fitted by elastic deformation.
This is a light quantity adjusting device in which the slit-shaped openings are arranged in a direction substantially orthogonal to the facing direction of the pair of magnetizing members, and the substrate is made of synthetic resin.

[0012]

FIG. 3 shows a light amount adjusting device used in a camera, a video camera or the like which is an embodiment of the present invention.

FIG. 4 is an exploded perspective view thereof. In this figure, the substrate 1 has an optical axis opening 5, and a guide pin 1a for regulating and guiding the movement direction of the light amount adjusting blade on a surface supporting the light amount adjusting blade, and the moving direction is regulated. L for holding on the surface to guide and support
A holding guide pin 1b having a shape is provided.

The light quantity adjusting blades 6 and 7 are formed of a thin piece of black polyester or the like, and have a function of blocking the optical axis opening by moving.

The light quantity adjusting blade 6 is provided with slits 6a and 6b, which are inserted into the guide pin 1a and the holding guide pin 1b provided on the substrate 1, respectively, and the moving direction is regulated and guided on the substrate 1 so as to be slidable. Supported by.

Further, the light amount adjusting blade 7 is provided with slits 7a and 7b, and guide pins 1a provided on the substrate 1 are provided.
Is inserted into the holding guide pin 1b and the light amount adjusting blade 6 is sandwiched between the substrate 1 and the holding guide pin 1b, and the movement direction is regulated and guided on the substrate 1 and supported slidably.

At this time, the light amount adjusting blade 7 has three slits 7b held by the holding guide pins 1b of the substrate, and the slits 7c are fitted and held by the connecting pins 4c of the arm 4, which will be described later, to hold at three points. , It will be held without falling off from the substrate. Further, the light amount adjusting blade 6 is supported by the slits 6b and 6c only at two points in the same manner as above, but since it is sandwiched between the light amount adjusting blade 7 and the substrate 1, it is also held without dropping off from the substrate. It

The magnet rotor 3 is, as shown in FIG.
It is composed of a cylindrical magnet 9 which is magnetized in two poles in the radial direction, and an arm 4 which is fixed by penetrating the center of the cylinder of the magnet 9, and as shown in FIG. Shafts 4a and 4b are formed on both ends of the connecting pin 2a
・ 2b is formed.

In this magnet rotor 3, after the shaft portion 4a is inserted into the bearing portion 2a formed on the substrate, the shaft portion 4b is inserted from the slit-shaped opening 2c by utilizing the elastic deformation of the bearing portion 2b to obtain the bearing hole diameter. Try to fit in 2e. Further, after that, the slits 6c and 7c provided in the light amount adjusting blades 6 and 7 are expanded by elastic deformation of the light amount adjusting blades, and are fitted into the connecting pins 4d and 4c, respectively, and the magnet rotor and the light amount adjusting blades are connected. It In this state, each shaft and bearing have a clearance, and the magnet rotor can reciprocate.

As described above in the problem to be solved by the invention, the clearance differs between the B direction and the C direction, and the fitted clearance amount is larger in the B direction.

In the present embodiment, the bearing hole 2a on the side closer to the light quantity adjusting blade has a round hole shape. However, this is because the bearing shape of 2b, which has a larger fitting clearance amount depending on the direction, is located on the far side, and there is shaft play. This is to reduce the influence on the light quantity adjusting blade. In the case of use such as a shutter in which the light amount adjusting blades are opened and closed instantly, and there is no need to consider the influence of backlash, it is not limited to this embodiment, and at least one of them may have the shape of the bearing portion 2b.

FIG. 6 is an exploded perspective view of the excitation unit 10 shown in FIG. The magnetic attraction member 11, which is a ferromagnetic material, is formed in a substantially U-shape and has magnetic poles 11b and 11c facing each other, and a connecting portion 11a is fitted into a concave groove portion 12a of the coil frame 12. At this time, a hooking claw 12b is formed on the opening side of the recessed groove 12a so as to narrow the opening width, and when the magnetism-inducing member 11 is inserted, the opening is enlarged due to elastic deformation and the coil is inserted. The space of the frame 12 around which the coil is wound is hooked with a gap.

As a result, a problem is caused by the contact between the magnetic attraction member 11 which is a ferromagnetic body and an electric conductor and the coil 15,
For example, a short circuit can be prevented. The terminal pin 13 is inserted and fixed in the hole formed in the coil frame 12.

In the exciting unit 10 thus constructed, the coil 15 is wound with the magnetizing member 11 incorporated in the coil frame 12 as shown in FIG. 4, and then the wire end of the coil is connected to the terminal pin. Wound 13 and printed with copper wire 14
It is connected with a copper wire printing plate and solder etc. through the small hole.

Further, the positioning hole 11d of the magnetic attraction member 11 is inserted into the positioning pin 1c provided on the substrate 1, the magnetic attraction member 11 is positioned on the substrate 1, and the coil frame 12 is provided on the substrate 1. When it is fitted and fixed in the fixed claw 1d, it is sandwiched and fixed by the bottom of the concave groove portion of the coil frame 12 and the substrate 1.

The light quantity adjusting device constructed as described above is as shown in FIG. The substrate 1 is provided with the light amount adjusting blades 6 and 7, the magnet rotor 3 and the excitation unit 10, and the coil 15
The magnetizing member 11 is magnetized by the current flowing through the magnetic pole 11b.
And 11c generate magnetic poles. Due to the generation of the magnetic poles, the magnet rotor 3 magnetized into two poles in the radial direction rotates, and the connecting pins 4c and 4d formed on the magnet rotor 3 are rotated.
The light amount adjusting blades 6 and 7 are moved by (not shown), and each light amount adjusting blade is opened and closed to adjust the amount of light passing through the optical axis opening 5.

In this drawing, the magnetism-applying member 11 is oriented in the opening direction B of the slit-shaped opening 2c which is opened to fit the shaft portion of the magnet rotor 3 of the bearing portion 2b formed on the substrate.
The magnetic pole direction C is substantially orthogonal to each other and is not affected by the fitting clearance E shown in FIG.
Magnetizing member 11 considering only the fitting clearance D shown in FIG.
And the air gap distance of the magnet rotor 3 can be set.

As described above, according to the present invention, with the above arrangement, even if the two rotor bearings are integrally formed on the substrate 1 and the magnet rotor 3 is mounted, the magnetizing member 11 and the magnet rotor 3 are caused by the above factors. It is possible to prevent a decrease in the air gap distance, and it is possible to eliminate the factor of inclination of the magnet rotor 3 due to mounting the magnet rotor 3 by integrally molding the two bearing portions on the substrate 1. Further, by eliminating the factor of this inclination, it is possible to reduce the air gap distance, which in turn makes it possible to improve the performance such as the shutter speed and power consumption of the light quantity adjusting device itself. Further, there is an advantage that a separate component for forming the bearing portion is not required, the number of components is reduced, and the magnet rotor 3 can be easily assembled.

[Brief description of drawings]

[Figure 1] Shape of bearing

2A is a B direction fitting diagram, and FIG. 2B is a C direction fitting diagram.

FIG. 3 is a perspective view of a light amount adjusting device.

FIG. 4 is an exploded perspective view

FIG. 5 is an exploded perspective view of a magnet rotor

FIG. 6 is an exploded perspective view of an excitation unit.

[Explanation of symbols]

1 substrate 2a Bearing part 2b Bearing part 2c slit-shaped opening 3 magnet rotor 4 arms 6 Light intensity adjustment blades 7 Light intensity adjustment blade 9 magnets 10 Excitation unit 11 Magnetic attraction member 11b magnetic pole 11c magnetic pole 12 coil frame

Claims (2)

[Claims] 1. A substrate having an optical axis opening, a light quantity adjusting blade arranged in the optical axis opening, a magnet rotor connected to the light quantity adjusting blade and having a rotation axis at its center, and an air gap in each of the magnet rotors. In a light quantity adjusting device comprising a pair of magnetizing members that are arranged to face each other and a coil that generates magnetic poles in the magnetizing member, a pair having a bearing hole that fits and supports the rotating shaft of the magnet rotor. Of the bearing part is integrally formed with the substrate, and at least one of the bearing parts is provided with a slit-shaped opening that is continuous with the bearing hole and into which the rotary shaft is fitted by elastic deformation. A light quantity adjusting device arranged in a direction substantially orthogonal to a facing direction. 2. The light quantity adjusting device according to claim 1, wherein the substrate is made of synthetic resin.