JPH0719014B2 - Light control device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electromagnetically driven exposure amount adjusting device, and more specifically, to a shutter and a diaphragm device provided in a still camera, a video camera, an interchangeable lens thereof and the like. The present invention relates to a light amount adjusting device.

[Prior Art] In a conventional light amount adjusting device of this type, one bearing of a rotor of a stepping motor is provided on a drive base plate, and the drive base plate is coupled to a cam plate with a screw.

[Problems to be Solved by the Invention] As described above, in the conventional light amount adjusting device, since the drive base plate is one of the bearings of the rotor of the stepping motor, the number of parts is large, and the drive base plate is a screw. Since it is connected to the cam plate, it is necessary to accurately adjust the inter-axis distance of the drive gear, which increases the number of assembly and adjustment man-hours and raises the cost.

The present invention is intended to solve such a problem.

[Means for Solving the Problems] The structure of the light quantity adjusting device of the present invention is configured such that diaphragm blades that adjust the light quantity by moving, a rotor having a plurality of magnetic poles, and a position facing the magnetic poles of the rotor. A stator having a magnetic pole portion, an exciting coil for exciting the stator, a rotating member that supports the diaphragm blade and rotates by receiving rotation of the output gear of the rotor, and a movement for adjusting the light amount of the diaphragm blade. And a cam member having an opening through which a light beam passes, and the diaphragm blade moves based on the cam portion of the cam member when the rotating member rotates to adjust the amount of light. The cam member includes a bearing portion of one shaft of the rotor, a first positioning portion that rotatably positions the rotating member, and a second positioning portion that positions the stator.
And a positioning portion of the.

[Operation] In the light amount adjusting device according to the present invention having the above-described structure, the bearing portion functions as a rotor bearing, the first positioning portion functions as a rotary member positioning function, and the second positioning portion functions as a stator positioning function. Since the cam member has the function of, the number of parts can be reduced and the number of connecting portions can be reduced, so that the number of assembling steps can be reduced. Further, the axial distance of the rotor is uniquely determined because the bearing is provided on the cam member, and the adjustment of the axial distance becomes unnecessary. Further, since the cam member is provided with the positioning function of the rotating member and the stator, the positional accuracy of the rotating member and the stator is improved.

[Embodiment] FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

In FIG. 1, 1 is a cam plate, 2 is an open switch, 3 is a light-shielding diaphragm blade, 4 is a rotating ring, 5 is a stator, and 6
Is an exciting coil, 7 is a stator, 8 is a rotor, 9 is a stator, 10 is an exciting coil, 11 is a stator, and 12 is a base plate.

That is, the cam plate 1 has the same number of cam grooves 1A as the diaphragm blades 3 for controlling the positioning of the diaphragm blades 3. Further, on the outer peripheral portion of the cam plate 1, there are provided a rotating ring 4 and a claw portion 1B for constituting a bayonet mechanism. This claw portion 1B is provided at three or more places. 1C is a bearing that rotatably supports the rotor 8.
1D is a support for incorporating the stator 5 and the exciting coil 6,
Similarly, 1E is a column for incorporating the stator 9 and the exciting coil 10. That is, 1D and 1E are columns for positioning.

The diaphragm blade 3 includes a plurality of blades (five in this embodiment),
As the rotating ring 4 rotates, the aperture blade 3 is moved by the dowel 3B of the aperture blade 3 which is connected to the hole 4E of the rotating ring 4. At this time, the dowel 3A (see FIG. 5) on the surface of the diaphragm blade 3 opposite to the dowel 3B moves in the cam groove 1A of the cam plate 1,
A diaphragm aperture surrounded by the diaphragm blade 3 performs an opening / closing operation.

The rotary ring 4 is provided with a claw portion 1B of the cam plate 1 and a notch portion 4A constituting a bayonet mechanism at a position corresponding to the claw portion 1B. Reference numeral 4B is a lever for driving the opening switch 2 for detecting the opening state of the aperture diameter of the aperture blade 3. When the diaphragm blades 3 are open, the opening switch 2 and the stator 5
The open switch dowel 13 is pushed off by the open switch lever 4B and is in a non-conductive state. When the rotary ring 4 rotates and the diaphragm blade 3 is narrowed down, the open switch 2 and the open switch dowel 13 are brought into conduction.

The role of the opening switch 2 is a switch that makes an electric signal when the diaphragm blade 3 is in the open state. Since this uses a stepping motor as a drive source, it is controlled in an open loop, preventing troubles when the diaphragm blades 3 do not operate for some reason, or turning on the system that uses this device. When quickly opened, the diaphragm blade 3
This is a switch that allows you to check the status of.

FIG. 2 shows a state in which the opening switch 2 is incorporated. 1F is a shaft of the opening switch 2 and 1G is a rotation stopper of the opening switch 2. Since the shaft 1F and the rotation stopper 1G are integrally formed with the cam plate 1, the positional accuracy can be increased. The open switch dowel 13 is fixed to the stator 5 and is also electrically conductive. Reference numeral 14 denotes a flexible wiring board for connecting the signal of the open switch 2 to the drive circuit, which is soldered to the end portion of the open switch 2 and the stator 5.

Another role of the opening switch lever 4B prevents the rotating ring 4 from coming off the cam plate 1. This is because the rotating ring 4 and the cam plate 1 are attached by the bayonet method as described above, so that the rotating ring 4 and
When is rotated, it comes off. Therefore, by incorporating the stator 5, the end surface 5C of the stator 5 prevents the release switch lever 4B from slipping off and prevents the bayonet from coming off.

The rotation stop dowel 4C of the rotary ring 4 is another stopper for preventing the rotary ring 4 from slipping off, and the end face of the stator 9 prevents the bayonet from slipping off, as described above. That is, the rotating ring 4 does not come off from the cam plate 1 by incorporating the stator 5 and the stator 9 after incorporating the rotating ring 4. That is, the end surface 5C of the stator 5 and the end surface of the stator 9 also serve as rotation limiting members that mechanically prevent over-rotation of the rotating ring 4.

The stators 5, 7, 9, 11 have comb-shaped magnetic pole portions 5A, 7A, 9A, 11A facing the rotor 8 and connection portions 5B, 7B, 9B, 11B forming magnetic paths.

The stators 5 and 7 are magnetically connected by the connecting portions 5B and 7B,
Create one phase. The stators 9 and 11 likewise form one phase. Each phase has an excitation coil 6,10. That is, this embodiment shows the case where a two-phase stepping motor is used.

FIG. 3 shows the state of the connecting portion of the stator, and FIG. 4 shows its cross section.

The stators 5, 7, 9 and 11 are positioned and incorporated by the columns 1D and 1E of the cam plate 1, respectively. The connecting portions 5B, 7B, 9B and 11B are formed by bending a part of the stators 5, 7, 9 and 11 by press working, but it is impossible to closely contact the two connecting portions due to the processing accuracy. That is, since the stators 5, 7, 9, 11 are positioned by the columns 1D, 1E provided on the cam plate 1,
It is impossible to process the connection part so as to be in close contact.

Therefore, as shown in FIG. 3, dimensions are determined in advance so that a gap is formed in the connection portion. By doing so, it is possible to prevent the connection portion from being taut and prevent the stators from being correctly positioned by the columns 1D and 1E. But,
From the viewpoint of magnetic characteristics, the presence of an air gap between the stators increases magnetic resistance, which causes deterioration of motor characteristics. Therefore, as shown in FIG. 4, magnetic saturation can be suppressed by filling the gap portion with the magnetic substance 16. This magnetic body 16
Particles of soft magnetic material such as iron and ferrite or liquid, or a mixture of these with an adhesive or the like is preferable.

The rotor 8 is formed by a plastic magnet, and the shaft 8C and the pinion gear 8B are also integrally formed.
This makes it possible not only to make the shaft 8C and the magnet 8D coaxial with high accuracy, but also to provide a dowel (or recess) 8A on the end face of the magnet 8D, and if the dowel 8A is used as a reference to magnetize the magnetic poles. The positional relationship between the position of and the pinion gear 8B can be accurately guaranteed. As a result, when the rotor 8 is assembled in the stator, if the dowel 8A is set at a predetermined position, the position (angle) of the rotary ring 4 is also determined, and the diaphragm blades 3
The required accuracy can be assured without fine adjustment of the open position of.

Exciting coils 6 and 10 consist of stators 5 and 7 and stators 9 and 1, respectively.
Built in between 1. The winding ends of the exciting coils 6 and 10 are passed through the holes of the stators 7 and 11, drawn out to the upper surface of the base plate 12, and connected to a printed wiring board or a flexible wiring board (not shown). Further, as shown in FIG. 1, the base plate 12 has a bearing 12A for the rotor 8 and rotatably axially supports the rotor 8. The base plate 12 is positioned and attached by the columns 1D and 1E of the cam plate 1.

As shown in FIG. 1, in a light quantity adjusting device configured by integrally incorporating a stepping motor and a diaphragm device,
In the stepping motor section, a current flows through the exciting coils 6 and 10 to generate a repulsive force and an attractive force to the rotor 8 and the magnetic pole sections 5A, 7A, 9A and 11A. The child 8 rotates. The amount of rotation of the rotor 8 is the same as in a general stepping motor.
Determined by the combination of off. Energization of the rotor 8 is started after confirming the state of the opening switch 2.

If the opening switch 2 is on and the diaphragm blades 3 are narrowed down, the rotor 8 is energized in the direction in which the diaphragm blades 3 are opened, and continues until the opening switch 2 is turned off. Only when the opening switch 2 is turned off and the diaphragm blades 3 are opened, the diaphragm blades 3 are energized in the direction in which they are narrowed down. A pinion gear integrally formed with the rotor 8 as the rotor 8 rotates a certain amount in the direction of narrowing.
The rotating ring 4 engaged with 8B rotates. Rotating ring 4
The aperture blade 3 is also operated by the dowel 3B in accordance with the rotation of. The dowel 3A of the diaphragm blade 3 operates in the cam groove 1A of the cam plate 1 to control the position of the diaphragm blade 3 to determine the diaphragm aperture. Exposure is performed when the aperture diameter is determined. After that, the diaphragm blades 3 are returned to the open state again, confirmation is made by the open switch 2, and all the operations are completed.

Next, the assembly procedure will be described.

FIG. 5 shows a jig 15 for incorporating the diaphragm blade 3. The jig 15 has a reference surface for receiving the cam plate 1 and the cam plate 1.
Has a conical pin 15A at the tip that fits into the through hole 1H provided in the cam groove 1A.

When the cam plate 1 is set on the jig 15 the conical pin 15A
Enters the through hole 1H. Next, the conical recess of the dowel 3A of the diaphragm blade 3 is fitted in the conical pin 15A of the jig 15 described above. Since this determines one point where the diaphragm blade 3 is installed, the dowel 3B is used as a fulcrum to rotate the dowel 3B.
The diaphragm blade 3 may be moved to a position that matches the hole 4E. After the position of the diaphragm blade 3 is determined, the rotary ring 4 is assembled. At this time, the claw portion 1B of the cam plate 1 comes to the position of the cutout portion 4A of the rotary ring 4. At this point, remove the cam plate 1 together with the rotary ring 4 from the jig 15
To rotate. Then, the claw portion 1B of the cam plate 1 and the rotating ring 4
Since the position of the notch portion 4A is displaced, the rotating ring 4 does not disengage from the cam plate 1. After that, the stators 5 and 9 are assembled according to the columns 1D and 1E. By incorporating the stators 5 and 9, the release switch lever 4B and the rotation stopper 4C of the rotary ring 4 prevent the bayonet mechanism of the rotary ring 4 and the cam plate 1 from coming off.

After this, the opening switch 2 is assembled to the cam plate 1. The cam plate 1 is integrally formed with the shaft 1F of the opening switch 2 and the rotation stopper 1G. After incorporating the opening switch 2, the rotary ring 4 is rotated to open the diaphragm blades 3. Then, the dowel 8A of the rotor 8 is set and incorporated in a predetermined position, and the gear portion 4D of the rotary ring 4 and the pinion gear 8B of the rotor 8 are engaged with each other.

On the other hand, the base plate 12 and the stators 7 and 11 are fixed in advance, and the exciting coils 6 and 10 are incorporated in the connecting portions 7B and 11B.
This subunit is assembled next to the rotor 8. At this time,
As described above, if the air gaps of the connecting portions 5B and 7B, 9B and 11B have a problem in motor characteristics, the magnetic material 16 is filled in between. This may be applied to the connecting portions 5B and 9B before the sub-unit is assembled.

Finally, the tips of the columns 1D and 1E, that is, the portions protruding from the base plate 12 may be fixed by heat welding or the like. After that, the terminals of the exciting coils 6 and 10, the opening switch 2 and the stator 5 may be connected to the drive circuit by a lead wire, a printed wiring board or a flexible wiring board.

Although the assembly procedure has been described above, there is no step to be adjusted, and the assembly can be completed by sequentially assembling according to the determined procedure.

[Effects of the Invention] As described above, according to the present invention, a bearing portion of one shaft of a rotor, a first positioning portion that rotatably positions a rotating member, and a second positioning portion that positions a stator on a cam member.
Since the cam member that positions the axial position of the rotor can also position the stator by forming the positioning portion of, the positional accuracy of the rotor and the stator is also improved,
The operation efficiency can be improved, and the conventional drive base plate and its mounting screw are not required, so that the number of parts and the weight can be reduced.

Further, since the positions of the rotor shaft and the rotating member are simultaneously positioned by the cam member, mutual positional accuracy is improved. That is, the distance between the shafts of the output gear of the rotor and the rotating member can be made highly accurate, and the driving efficiency can be improved.

Further, since the diaphragm blade is supported by the rotating member and the rotating member is positioned by the cam member having the cam portion for guiding the movement of the diaphragm blade, the positional accuracy of the rotating member with respect to the cam member is improved by the operation of the diaphragm blade. The accuracy can also be improved, and an accurate light amount adjustment operation is possible.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention, FIG. 2 is an enlarged perspective view showing an example of assembly of the open switch of FIG. 1, and FIG. 3 also shows a connecting portion of the stator. FIG. 4 is an enlarged perspective view, FIG. 4 is an enlarged sectional view of the same, FIG. 5 is a perspective view showing an example of an assembling process of the diaphragm blade of FIG. 1, and FIG. 6 is an enlarged sectional view of the same. 1 ... Cam plate, 1C ... Bearing, 1D, 1E ... Post, 3 ... Aperture blade,
4 ... Rotating ring, 5, 7 ... Stator, 8 ... Rotor, 8C ... Shaft, 9, 11 ... Stator, 12 ... Base plate, 12A ... Bearing.

Claims (1)

[Claims] 1. A diaphragm blade for adjusting the amount of light by moving, a rotor having a plurality of magnetic poles, a stator having a magnetic pole portion at a position facing the magnetic pole of the rotor, and an exciting coil for exciting the stator. A rotary member that supports the diaphragm blade and rotates by receiving rotation of the output gear of the rotor; a cam member that sets a movement for adjusting the light amount of the diaphragm blade; and a cam member that has an opening through which a light beam passes. The aperture blade is configured to move based on the cam portion of the cam member by the rotation of the rotating member to adjust the amount of light, and the cam member is a bearing of one shaft of the rotor. A light amount adjusting device comprising: a portion, a first positioning portion that rotatably positions the rotating member, and a second positioning portion that positions the stator.