JPS6134132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to an electromagnetic device for a camera that facilitates winding of a coil and also makes it possible to increase the utilization rate of conductors.

As an electromagnetic device for a camera, there are devices such as Utility Application No. 52-127326 and Utility Model Application No. 54-53437 related to the earlier application of the same applicant, but this conventional device is shown in Figs. 1 and 2. As shown, electromagnetic devices 2 are arranged on a plate 1 at equal intervals around the optical axis, and each electromagnetic device 2 includes a stator coil 22 wound around a frame 21, a permanent magnet rotor 23, and a permanent magnet rotor 23. Rotor 23
The actuating arm 24 is fixed to the actuating arm 24.
Moreover, a notch 31 shared by each electromagnetic device 2
a shield plate 3 formed with an actuating arm 2;
The shutter blade 5 is opened and closed via a pin 241 installed on the sector ring 4.

In this conventional electromagnetic device 2 , a fixed coil 2
2 has a conductor part running perpendicular to the optical axis and a conductor part running parallel to the optical axis, but the conductor part running parallel to the optical axis is connected to a permanent magnet rotor in order to increase electromagnetic efficiency. It is necessary to wind it in a pot-belly shape, for example, in accordance with the outer diameter curvature of No. 23, and this winding work is troublesome. In addition, the winding work must be performed after the permanent magnet rotor 23 is pivotally supported within the frame 21, which imposes restrictions on the assembly process and requires repairs to the shaft support relationship of the permanent magnet rotor 23. When replacing a broken coil 22, the coil 22 must be unwound, which is troublesome.

Further, since the permanent magnet rotor 23 is magnetized in a direction perpendicular to the optical axis, the current flowing through the conductor portion of the fixed coil 22 running in a direction perpendicular to the optical axis rotates the rotor 23. It does not contribute to the electromagnetic effect, and therefore, the conducting wire portion is in some respects wasteful, and the utilization rate of the conducting wire in the fixed coil 22 of the conventional electromagnetic device 2 has been inevitably low.

The present invention eliminates the drawbacks of conventional electromagnetic devices as described above, and uses a permanent magnet rotor configured to be magnetized in a direction parallel to the optical axis, so that the fixed coil is aligned orthogonally to the optical axis. By making it possible to construct only the conductive wire portion wound around the optical axis in the plane, the permanent magnet rotor, fixed coil, etc. can be assembled independently and sequentially, which facilitates the coil winding work. The present invention provides an electromagnetic device for a camera that is easy to assemble and disassemble.

In addition, by arranging a large number of permanent magnet rotors at equal distances and intervals around the optical axis,
It is an object of the present invention to provide an electromagnetic device that can extremely increase the conductor utilization rate of a fixed coil.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 6.

First, in FIGS. 3 to 5, numeral 31 is a shutter case in which an aperture 311 is formed, 32 is a donut-shaped shield plate, and 33 is a donut wound around the optical axis in a plane perpendicular to optical axis 0. 34 is the first fixed coil of the shape of the coil 33;
It is a donut-shaped shaft mounting seat with a U-shaped side wall surrounding the shaft, and is made by molding. Reference numeral 35 denotes a rotating shaft, which is fixed to the shaft mounting seat 34 by an insert. A permanent magnet rotor 36 is rotatably inserted into the rotating shaft 35, and the right half and the left half are magnetized in opposite directions in a direction parallel to the optical axis 0. 37 is an operating arm supported so as to rotate integrally with the rotor 36; 38 is a circular screw member for preventing the rotor 36 and the operating arm 37 from coming off; 3;
9 is a second fixed coil formed similarly to the first fixed coil 33 placed on the member 38; 40;
41 is a donut-shaped shield plate, 41 is a pin implanted at the tip of the operating arm 37, 42 is a sector ring formed with a U-shaped groove 421 that fits with the pin 41, and has a pin 422 implanted therein; This is a shutter blade showing one of a set of five shutter blades that are opened and closed.

Note that the illustrated state shows that the permanent magnet rotor 36 has reached the center of rotation.

As shown in FIG. 5, the magnetic flux emitted from the north pole of the permanent magnet rotor 36 enters the opposite south pole via the shield plates 32 and 40, respectively. Therefore, the respective magnetic fluxes are effectively distributed between the first and second fixed coils 33,
Cross 39. Now, when current flows in the direction of the arrow in the fixed coils 33 and 39, the permanent magnet rotor 36 rotates to the left according to Fleming's left hand rule, and the operating arm 3
7-Pin 41-U-shaped groove 421-Centering 42
- Opening the shutter blade 43 via the pin 422. Then, when the current is applied in the opposite direction, the shutter blade 43 is closed.

Figure 4 is a sectional view taken along the - line in Figure 3;
The figure is a cross-sectional view taken along the - line in FIG. 3, and the cross-sections of all rotor parts are the same. In order to smooth the balance of forces, a plurality of rotors are arranged at equal intervals, but it is not necessary to arrange as many rotors as shown in FIG. 3.

FIG. 6 shows a simplified rotor of another embodiment corresponding to FIG. The rotor is constructed by sandwiching the magnetic material between the magnets 36' and 36'' so that their magnetic poles face each other. According to this embodiment, the magnetic pole arrangement on the upper and lower surfaces of the rotor is the same as that of the previous embodiment. Since it is different from the fixed coil 3
In order for the electromagnetic action when current flows through 3 and 39 to act as rotational force in the same direction, the respective currents may be applied in opposite directions as shown by the arrows.

Note that in order to stably maintain the closed and open states of the shutter blades 43, it is necessary to continue supplying a current that provides a driving force in each direction of rotation. If a notch equivalent to the notch 31 formed in the shield plate 3 of No. 127326 (Japanese Utility Model Publication No. 54-53437) is formed in the shield plate 32 and/or 40, the rotor of the present invention can also be improved. Can be pulse driven.

In addition, although the embodiment shows an electromagnetic device that drives the shutter blades of a camera, it can also be applied to a device that drives aperture blades, and when the sector ring 42 is viewed as an aperture operating member, for example, a cam may be formed on that member. However, an aperture setting member for stopping the rotation midway may be placed in front of the rotation range of the cam.

Furthermore, the fixed coil can also be formed as an air-core coil by using self-welding wire.

As described above, in the present invention, the fixed coil can be wound around the optical axis in a plane orthogonal to the optical axis and can be configured independently of the permanent magnet rotor, making the winding work extremely easy and mass-producible. It is easy to assemble and disassemble. Further, by providing multiple permanent magnet rotors, it is possible to increase the utilization rate of the conductor of the fixed coil, and at the same time, it is possible to make the device flat and compact.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a shutter incorporating a conventional electromagnetic device, Fig. 2 is an enlarged plan view of the electromagnetic device incorporated in Fig. 1, and Fig. 3 is a plan view of a shutter incorporating the electromagnetic device of the present invention. 4 is a sectional view taken along the line -- in FIG. 3, FIG. 5 is a sectional view taken along the line -- in FIG. 3, and FIG. 6 is an explanatory view of another embodiment corresponding to FIG. 5. 31... Shutter case, 32, 40... Shield plate, 33, 39... Fixed coil, 36... Permanent magnet rotor, 37... Working arm, 42... Sector ring, 43... Shutter blade, 36', 36″…
...Permanent magnet, 44...Magnetic material.

Claims (1)

[Claims] 1. Two fixed coils wound around the optical axis in a plane perpendicular to the optical axis, and a plurality of permanent magnets arranged at equal intervals with rotation centers at positions equidistant from the optical axis. rotor, each permanent magnet rotor is rotated by the electromagnetic action of the magnetic flux parallel to the optical axis of the permanent magnet rotor and the current flowing through the fixed coil, and the shutter blade or aperture blade is rotated. An electromagnetic device for a camera, characterized in that it is configured to drive directly or indirectly.