JPH1048697A - Driving device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device for a camera having a small number of parts and also whose axial position is highly accurate, at a low cost. SOLUTION: A container-like rotor storing part S is partly formed on a shutter base plate 1, and a supporting plate 2 is installed opposite to the part S, and a rotor shaft 3 is directly supported by bearing parts installed on both of the plates 1 and 2. A rotor 5 constituted of a permanent magnet is fixed on the rotor shaft 3, and a driving pin 4 is rotated in accordance with the rotation of the rotor shaft. A coil 8 is directly wound around a coil frame part 7 formed on the shutter base plate 1 and the supporting plate 2 so as to be parallel to the rotor shaft 3. When the coil 8 is energized, the rotor is rotated only at a prescribed angle, then, a sector 6 is rocked by the driving pin 4, then, a shutter opening/closing operation is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera driving device.

[0002]

2. Description of the Related Art A rotor is provided inside a pin-shaped coil frame as a camera driving device used for opening / closing a shutter when a lens is driven by an automatic focusing device of the camera or a shutter is released, and a coil is wound around the coil frame. A configuration in which the periphery is surrounded by a yoke has been proposed (Japanese Utility Model Laid-Open No. Hei 3-22228). In this proposal, an arm is provided integrally with the lower end of the rotor shaft, a driving pin is provided at the end of the arm, and the rotor is rotated by a predetermined rotation angle by energization. It returns to the original position. However, when a return spring is used, there is a problem that energy consumption at the time of energization becomes large, and it is difficult to obtain a stable operation due to variations in accuracy and mounting of the spring.

[0003] In order to solve this problem, there has been proposed an apparatus in which the coil frame and the yoke are formed in an oval shape so that the drive pins coincide with the longitudinal direction of the oval shape (actual flat type 7).
014439). According to this proposal, the rotor is rotated by a rotation angle of about 30 degrees by energizing the coil, and the shutter blades and the like are opened via the drive pin. It has been proposed that the magnet can be reversed by an attractive force of a working magnet and returned to a rest position.

[0004]

In the above-mentioned prior art, it can be considered that the latter is an excellent proposal in that the return spring is not used, and the number of components is reduced and energy loss is achieved. However, even in the above proposal, the reduction in the number of parts is still insufficient, and there is a dislike that the demand for cost reduction is not satisfied. In addition, since both ends of the rotor shaft are supported by bearings provided on the upper and lower two coil frames, and the coil frames are mounted on the shutter base plate, the shaft position accuracy is insufficient, and the improvement in camera accuracy is hindered. There is a problem.

[0005]

Accordingly, the camera driving apparatus of the present invention firstly forms a coil frame by directly winding a coil on a shutter base plate, a support plate and a coil at a position surrounding the periphery of a rotor. By eliminating the need, the number of components is reduced. Second, the rotor shaft is directly supported by the bearing portions provided on the shutter base plate and the support plate, whereby the displacement of the rotor shaft can be prevented.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a camera driving device for rotating a rotor by a predetermined rotation angle from a stationary position by energizing a coil, and opening and closing shutter blades with the rotation of the rotor. . The rotor is housed in a rotor housing portion constituted by a shutter base plate and a support plate, the rotor shaft is supported by bearing portions provided on the shutter base plate and the support plate, and the coil is provided in the rotor housing portion. A shield member for preventing magnetic flux leakage is attached to at least a part of the outer periphery of the rotor storage portion which is wound directly around the shutter base plate and the support plate so as to surround the outer periphery of the rotor. There is a characteristic.

[0007]

FIG. 1 is an enlarged view of a main part of an embodiment of the present invention. A rotor base S having an oval cross section is formed in a shutter base plate 1 as a component. The support plate 2 provided so as to face the shutter base plate 1 is fixed to the shutter base plate 1 at a position (not shown) so that both are integrated. Bearing portions 1a and 2a are provided at the center position of the rotor storage portion S formed on the shutter base plate 1 and at a position facing the support plate 2 at both ends. Are fitted. The rotor shaft 3 is rotatably and directly supported by the shutter base plate 1 and the support plate 2. In the vicinity of the lower end of the rotor shaft 3, an arm portion 3 a is provided so as to extend inside the long axis of the oval-shaped rotor storage portion S.
Is formed.

A driving pin 4 projects from the tip of the arm 3a toward the support plate 2. The drive pin 4 is engaged with an arc-shaped hole 2b provided in the support plate 2, and can swing along the arc-shaped hole when the rotor shaft 3 rotates. A rotor 5 composed of a cylindrical permanent magnet is fixed to the rotor shaft 3. A sector 6 constituting a pair of shutter blades is located below the arm 3a of the rotor shaft 3, and a mounting hole 6a provided at an end of one of the sectors 6 is provided with a rotor shaft 3a. Is fitted. On the other hand, the drive pin 4 is fitted in a drive hole 6b provided at a predetermined distance from the mounting hole 6a of the sector 6. Therefore, when the rotor shaft 3 rotates, one sector 6 can swing about the rotor shaft 3. The drive pin 4
Although not shown, the drive holes of the other sector of the pair of sectors 6 are also fitted. The other sector is swingably supported by a support shaft erected at another position on the shutter base plate 1, and both sectors simultaneously swing in the opposite direction by the rotation of the rotor shaft 3. A shutter opening (not shown) can be opened and closed.

The cross section of the periphery of the rotor housing portion S of the shutter base plate 1 is rectangular, and the flange portions 1b,
1b is formed, and a concave portion 1c for coil winding is provided inside thereof. Also, at the position of the support plate 2 facing the rotor storage section S, a recess 2d for coil winding is provided by providing projections 2c, 2c. These recesses 1c,
2d constitutes a rectangular coil frame portion 7 having both sides in the axial direction of the rotor shaft 3 and in a direction orthogonal to both ends as a whole. A coil 8 is directly wound around the coil frame portion 7 composed of the concave portions 1c and 2d. The shutter base plate 1
A shield member 9 for preventing a magnetic flux generated by energizing the coil 7 from leaking to the outside is provided on the outer periphery of the rotor housing portion S.

[0010]

[Operation] In the initial state, each sector keeps the shutter opening closed by a spring (not shown).
At this time, the rotor 5 is stably stopped at a position where both the N-pole and the S-pole substantially face the short diameter portion of the shield member 9. The drive pin 4 is located at the center of the arc-shaped hole 2b of the support plate 2. Next, when a voltage is applied to the coil 8 from a control circuit (not shown), the rotor 5 rotates to the right by a predetermined rotation angle due to the magnetic flux generated from the coil. Accordingly, the drive pin 4 moves along the arcuate hole 2b to swing the sector 6 to open the shutter opening.
When the shutter opening is opened to a predetermined exposure amount, the control circuit applies a reverse voltage to the coil 8 to rotate the drive motor in the reverse direction to return the sector to the initial position.

The amount of exposure of the shutter opening is determined in advance based on data obtained by a photometric circuit, and the number of sectors necessary to obtain the swing of the sector necessary to make the opening corresponding to this amount of exposure is obtained. Control is performed by applying a pulse to the coil. In the above-described embodiment, the drive device for opening and closing the shutter opening is described. However, the present invention is also applicable to a diaphragm device and a lens drive of an automatic focus adjustment device. Although the planar shape of the rotor housing is described as an oval type, the shape is not limited to the oval type. In this embodiment, the control circuit applies a reverse voltage to the coil 8 to reverse the drive motor to return the sector to the initial position. However, the reverse voltage is not applied, and the magnet is attracted to the yoke. It may return to the initial position by force.

[0012]

According to the present invention, since the coil is wound directly around the shutter base plate and the support plate, a coil frame is not required, which contributes to a reduction in the number of parts and a reduction in cost. Further, since the rotor shaft is directly supported by the bearing portions provided on the shutter base plate and the support plate, it contributes to the improvement of the shaft position accuracy.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of one embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shutter base plate 1a Bearing part 2 Support plate 2a Bearing part 3 Rotor shaft 4 Drive pin 5 Rotor 6 Shutter blade (sector) 8 Coil 9 Shield plate S Rotor storage part

Claims (1)

[Claims] 1. A camera driving device for rotating a rotor by a predetermined rotation angle from a stationary position by energizing a coil and opening and closing shutter blades in accordance with the rotation of the rotor, wherein the rotor is a shutter. The rotor shaft is housed in a rotor housing portion constituted by a base plate and a support plate, the rotor shaft is supported by bearing portions provided on the shutter base plate and the support plate, respectively, and the coil is the rotor housing portion. A shield for preventing magnetic flux leakage is provided on at least a part of the outer periphery of the rotor housing portion which is wound directly around the shutter base plate and the support plate so as to surround the outer periphery of the rotor. A driving device for a camera, wherein a member is attached.