JP3510739B2 - Camera drive - Google Patents

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 conventional camera drive device used for opening and closing a shutter aperture of a camera, automatic focus adjustment, and the like has a structure in which a rotary ring is rotated by a step motor, and a shutter blade or the like is driven through the rotary ring. It is widely adopted. (For example, Japanese Patent Laid-Open No. 2-58035). However, such a configuration requires a coil frame, a coil, and a stator as the constituent elements of the step motor, and also requires a large number of components such as a rotating ring, which complicates the structure and increases the size thereof. Therefore, there is a problem that it is not suitable for compact cameras such as compact cameras.

On the other hand, a drive pin is provided on the rotor to which a rotor magnet having magnetic poles arranged in the axial direction is fixed, and the shutter blades can be directly swung by the drive pin, thereby making the device compact. A realization has been proposed (Japanese Utility Model Publication No. 3-22228). Further, in order to realize the function improvement of the above-mentioned proposal, a camera having a configuration in which a rotor magnet is surrounded by an oval-shaped coil frame, a coil is axially wound around this coil frame, and the outside of the coil is covered by an oval-shaped yoke. A drive device for a vehicle has been proposed (Japanese Utility Model Laid-Open No. 7-14439).

[0004]

Among the above-mentioned prior arts, the latter two can be said to have been considerably compacted structurally, but the coil frame is composed of an upper coil frame and a lower coil frame, and further, a yoke. However, the reduction of the number of parts is still insufficient, and there is still room for the shift to compact size. Further, since the rotor is attached to the coil frame, and the coil frame is attached to the shutter base plate, there is a problem that the accuracy of the axial position of the rotor is lowered and it takes time and effort to align the axial position.

[0005]

Therefore, the present invention adopts the following means in order to solve the above problems. First, by forming a coil frame part integral with the shutter base plate around the rotor and winding a coil around this coil frame part, an independent coil frame is not required and the number of parts is reduced. Secondly, the support plate provided so as to face the shutter base plate is made of a magnetic material, and the stator portion that functions as the stator is integrally provided so as to cover one half of the one surface of the rotor magnet. The number of parts is reduced by eliminating the need for such a stator. Third,
The rotor can be attached to the rotor support portion provided integrally with the shutter base plate to prevent deterioration of the axial position accuracy.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention includes a permanent magnet rotor and a stator coil that magnetically drives the rotor, and a coil frame portion around which the coil is wound is formed integrally with the shutter base plate around the rotor. The rotor is operably provided with a drive unit for driving the shutter blades, and a support plate for the shutter blades is provided on the opposite side of the shutter base plate, and the support plate is made of a magnetic material. In half of
Can only generate magnetic flux so as to cover approximately half of the above rotor
The formed stator part is integrally provided.

Further, the shutter base plate is provided with a rotor supporting portion, the tip of the rotor supporting portion is fitted into a supporting hole formed in the supporting plate, and the rotor is rotatable on the rotor supporting portion. Alternatively, the rotor may be rotatably provided on bearing portions provided on the support plate and the shutter base plate.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an essential part of a first embodiment of the present invention, and FIG. 2 is a plan view showing it. As shown in FIGS. 1 and 2, the rotor R is rotatably supported by a rotor support portion 1 a provided at a specific portion of the shutter base plate 1. The tip of the rotor support portion 1a is engaged with a support hole 2a formed in a support plate 2 provided so as to face the shutter base plate 1. As described above, the rotor R includes the rotor shaft 3 rotatably supported by the rotor support portion 1a and the rotor magnet 4 fixed to the rotor shaft 3. The rotor shaft 3 is provided with a shaft hole 3a at the center of the shaft, and the rotor support portion 1a described above is fitted in the shaft hole 3a. Further, the polarities of the rotor magnet 4 are arranged so that magnetic flux is generated in the axial direction.

The rotor shaft 3 has a disc portion 3b having an outer diameter slightly smaller than the outer diameter of the rotor magnet 4 formed on one side thereof, and one side portion of the rotor magnet 4 has this disc portion. It faces the side. An outward protruding portion 3c is formed at a specific position of the disc portion 3b, and a drive pin 5 as a shutter blade driving portion which is parallel to the rotor shaft 3 is provided upright on the protruding portion 3c. The tip of the drive pin 5 is the support plate 2
The arcuate hole 2 formed around the rotor shaft 3 as the center of rotation
It is located in the position b, and the rotor R can be rotated within the range of the arc length of the arcuate hole 2b. The arc-shaped hole 2b is formed by cutting out a portion of the support plate 2 that faces approximately half of the rotor magnet 4 so that the magnetic flux generated from the rotor R escapes and magnetic force from the stator is not generated (FIG. 3).

The drive pin 5 includes a pair of shutter blades 6 (1
It is fitted in the hole 6a (only one is shown). Since the shutter blade 6 has a shaft hole portion 6b provided at a position separated from the hole portion 6a by a predetermined distance and fitted into the rotor shaft 3, the drive pin 5 is rotated by the rotor R within the range of the arc-shaped hole portion 2b. It can swing by moving. The other shutter blade (not shown) also has the drive pin 5 fitted in the hole and the shaft hole fitted in the support pin (not shown) projecting from the shutter base plate 1. The shutter blades can swing in the opposite direction.
Therefore, when the rotor R reciprocally rotates within a predetermined angle range, the opening of the shutter can be opened and closed.

The rotor support 1a of the shutter base plate 1
Around the portion where is formed is a semi-circular disk portion 1b that covers the rotor R in a semi-circular shape (see FIG. 2), and the semi-circular disk portion 1b.
Is supported by the outer wall portion 1c. The outer wall portion 1c is
It is formed so as to surround the outer periphery of the rotor R, and flange portions 1d are formed at predetermined intervals to serve as a coil frame portion 1e. A coil 7 is wound around the coil frame portion 1e. The support plate 2 is made of a magnetic material such as permalloy or plastic containing magnetic powder, and the outer surface of the surface facing the rotor R is formed in a semicircular shape. One end 2c of the support plate 2 is an outer peripheral portion of the coil frame 1e. Is formed so as to face a part of. Support plate 2
Is further in contact with the other side surface of the coil frame portion 1e, and the rotor R
A stator portion 2d is provided extending toward the center of the.
The stator portion 2d is formed so as to cover approximately half of the rotor magnet 4, and functions as a stator that can generate magnetic flux only in this half portion.

FIG. 3 shows a plan view of the main part of the support plate 2. The arcuate hole 2b is formed in the rotor magnet 4.
Occupies almost half of the surface facing the
Covers approximately half of the facing surface of the rotor magnet 4 at a position symmetrical with the arcuate hole 2b. Therefore coil 7
When a magnetic flux is generated by energizing the rotor, a rotational force to the rotor R is generated in the portion covered by the stator portion 2d, but a rotational force is generated because there is no stator on the surface facing the arcuate hole portion 2b. It is impossible to make them.

In the camera driving device constructed as described above, the coil frame is replaced by the coil frame portion 1e integral with the shutter base plate, and the stator is formed as the stator portion 2d on the support plate 2 made of a magnetic material. Since they are replaced, both parts which were conventionally independent can be eliminated. Further, since the rotor R is pivotally supported on the rotor support portion 1a formed integrally with the shutter base plate 1, the coil frame alignment work which is required in the prior art is not required, so that the axial position is eliminated. The accuracy can be easily improved. Further, since the magnetic flux generated by the coil 7 is generated in the direction of the rotor shaft, leakage of the magnetic flux to the outside can be blocked by the support plate 2, and the influence of the magnetic flux on other electronic devices is less likely to occur.
Therefore, it is not necessary to provide a yoke around the rotor R for cutting magnetic flux.

In the initial state of this embodiment, that is, when the shutter blades are closed, as shown in FIG. 2, the polarity of the rotor magnet 4 is about 45 ° with respect to the center line of the stator portion 2d.
It is arranged so that it is only tilted. At this time, the drive pin 5 is located near the right end of the arcuate hole 2b. In the configuration described above, when the coil 7 is energized by the control means (not shown), the stator portion 2d
And, a magnetic force is generated in the portion of the support plate that faces this. As a result, the magnetic poles of the rotor magnet 4 are repelled, and the rotor R rotates clockwise (clockwise direction). As a result, the shutter blades 6 swing and open in opposite directions via the drive pin 5 to form a predetermined shutter opening at a position not shown. Next, when the coil 7 is de-energized, the repulsive force on the rotor R disappears, and the shutter blades return to their initial positions by the force of a return spring (not shown) to close the shutter opening. It is also possible to perform the above-described returning operation of the shutter blades by supplying a current in the opposite direction to the coil 7.

A second embodiment is shown in FIG. The same parts as those in the first embodiment use the same reference numerals. Further, the description will be omitted while omitting the same parts as those in the first embodiment, and the differences will be mainly described. The second embodiment is a case where the shutter base plate 1 is not provided with a rotor supporting portion. A bearing portion 1f for supporting the rotor shaft 8 on the shutter base plate 1 and the support plate 2,
2e are provided respectively. A rotor magnet 4 is fixed to the rotor shaft 8, and a disc portion 3b having an outer diameter slightly smaller than the outer shape of the rotor magnet 4 is formed on one side. One side portion of the rotor magnet 4 is in contact with the side surface of the disc portion 3b. Further, an outward protruding portion 3c is formed at a specific position of the disc portion 3b, and a driving pin 5 as a shutter blade driving portion which is parallel to the rotor shaft 8 is provided upright on the protruding portion 3c. It is a thing.

In the first embodiment, the rotor support portion is provided integrally with the shutter base plate, but the rotor support portion may be a separate member and fixed to the shutter base plate. Further, in the first and second embodiments, the shutter drive unit is integrally provided on the rotor shaft, but a member such as a train wheel may be interposed between the rotor shaft and the drive unit.

[0017]

According to the present invention, firstly, the coil frame is formed integrally with the shutter base plate, and the stator is replaced by the stator portion which is integrated with the support plate, which is different from the conventional one. Since the coil frame and the stator are not required, the number of parts is reduced, and the camera can be made compact and the manufacturing cost can be reduced.
Second, since the shutter base plate is integrally formed with the coil frame portion and the rotor support portion, and the support plate is integrally formed with the stator portion, the positions of the respective parts for maintaining the high precision of the rotor drive as in the prior art. No need for alignment.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a first embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a plan view of the support plate of the same.

FIG. 4 is a sectional view of an essential part of a second embodiment of the present invention.

[Explanation of symbols]

1 Shutter base plate 1a rotor support 1e Coil frame part 2 Support plate 2a Support hole 2b arcuate hole 2d stator part R rotor 3,8 rotor shaft 4 rotor magnet 5 Drive pin (drive unit) 6 shutter blades 7 coils

Continuation of the front page (56) Reference JP-A-3-145632 (JP, A) JP-A-3-279929 (JP, A) JP-A-7-281252 (JP, A) JP-A-10-274794 (JP , A) Actual Kaihei 5-64835 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 9/00-9/54

Claims (3)

(57) [Claims] 1. A permanent magnet rotor and a stator coil for magnetically driving the rotor, wherein a coil frame portion around which the coil is wound is formed integrally with a shutter base plate around the rotor, The rotor is operably provided with a drive unit for driving shutter blades, and a support plate for the shutter blades is provided on the opposite side of the shutter base plate. The support plate is made of a magnetic material. Half of the rotor
A drive unit for a camera, characterized in that a stator portion is integrally provided so as to generate a magnetic flux only on the rotor so as to cover substantially half of the rotor . 2. A rotor support portion is provided on the shutter base plate, and a tip of the rotor support portion is fitted into a support hole formed in the support plate. A driving device for a camera, wherein the rotor is rotatably provided on a supporting portion. 3. The camera drive device according to claim 1, wherein the rotor is rotatably provided on a bearing portion provided on the support plate and the shutter base plate.