JPH01101528A - Electromagnetically driven exposure adjusting device - Google Patents

Abstract

PURPOSE:To reduce the number of components and the man-hour of assembling processes by molding a shaft for fitting an opening switch and a rotation stop unitedly with a part of a cam plate. CONSTITUTION:The shaft IF of the opening switch 2 for converting the opening state of a stop blade 3 into an electric signal and the rotation stop 1G are formed unitedly with the cam plate 1. Thereby, position accuracy can be improved. An opening switch dowel 13 is fixed on a stator 5 and electrically kept at a conductive state. Since the opening switch is molded unitedly with the cam plate and fitted to the shaft and rotation stop is also formed, the number of components can be reduced and assembling property can be improved.

Description

[Detailed Description of the Invention] [Field of Application in Industry A] The present invention relates to an electromagnetic drive exposure adjustment device, and more specifically, to a shutter or aperture device installed in a still camera, a video camera, and their interchangeable lenses. The invention relates to an exposure amount adjusting device such as the above.

[Prior Art] In this type of conventional exposure adjustment device, the open switch for detecting the open position of the aperture blades is mounted on a pedestal on which the switch is mounted, and the pedestal is attached to a holding plate of a rotating ring. , was fixed by heat caulking.

[Problems to be Solved by the Invention] As described above, in the conventional technology, the open switch for detecting the open position of the aperture blades is mounted on a pedestal,
The problem is that because the pedestal is fixed to the holding plate of the rotating ring by heat caulking using ultrasonic waves, the pedestal becomes loose and the switching position of the open switch becomes unstable, requiring adjustment. In addition, there are problems in that the number of parts increases and the cost also increases.

The present invention attempts to solve these problems.

[Means for Solving the Problems] In an electromagnetic drive exposure adjustment device that uses a stepping motor as a driving source to open and close light-shielding aperture blades provided between a cam plate and a rotating ring, the opening and closing of the aperture blades is provided. The cam plate includes an open switch for detecting a state, and a shaft and a rotation stopper for the open switch are integrally formed in a part of the cam plate, and a part of the rotating ring includes: In addition to having an opening switch lever, a part of the stator of the stepping motor is provided with an opening switch dowel that has electrical conductivity with the stator and comes into contact with the opening switch when the aperture blades are narrowed. I took it as a thing.

[Function] According to the present invention, the open switch is attached to the shaft formed integrally with the cam plate, and is also prevented from rotating.
There is no wobbling of the pedestal like in the past, and the number of parts is reduced and ease of assembly is improved.

[Example] 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 diaphragm blade for light shielding, 4 is a rotating ring, 5 is a stator, and 6 is a rotary ring.
1 is an excitation coil, 7 is a stator, 8 is a rotor, 9 is a stator, 10 is an excitation coil, 11 is a stator, and 12 is a base plate.

That is, the cam plate 1 has the same number of cam grooves IA as the aperture blades 3 for controlling the positioning of the aperture blades 3. Also cam plate 1
A claw portion IB for forming a bayonet mechanism with the rotary ring 4 is provided on the outer periphery of the rotary ring 4. This claw portion IB is provided at three or more locations.

IC is a bearing that rotatably supports the rotor 8.

ID is a support for incorporating the stator 5 and excitation coil 6, and similarly, IE is a support for incorporating the stator 9 and excitation coil 10.

The aperture blade 3 consists of a plurality of blades (five in this embodiment),
As the rotary ring 4 rotates, the aperture blade 3 moves by the dowel 3B of the aperture blade 3 that connects with the hole 4E of the rotary ring 4. At this time, the dowel 3A (fifth (see figure) moves within the cam groove IA of the cam plate 1, so the aperture aperture surrounded by the aperture blades 3 performs opening and closing operations.

The rotary ring 4 is provided with a notch 4A forming a bayonet mechanism with the claw IB of the cam plate 1 at a position corresponding to the claw IB. 4B is a lever that drives the open switch 2 for detecting the open state of the aperture of the aperture blade 3. When the aperture blade 3 is in the open state, the open switch 2 and the open switch dowel 13 of the stator 5 are pushed away by the open switch lever 4B and are in a non-conducting state. When the rotating ring 4 rotates and the aperture blades 3 are narrowed down, the open switch 2 and the open switch dowel 13 become electrically connected.

The role of the open switch 2 is to generate an electrical signal indicating that the aperture blades 3 are in the open state. Since this uses a stepping motor as the drive source, it is controlled by an oven loop, which prevents trouble when the aperture blades 3 do not operate for some reason, and when the system using this device turns on the power. When the aperture blade 3
This is a switch that allows you to check the status of the

FIG. 2 shows a state in which the open switch 2 is installed. IF is the axis of the open switch 2, and IG is the rotation stopper of the open switch 2.

Since the shaft IF rotation stopper IG is integrally molded with the cam plate 1, high positional accuracy can be achieved. The open switch dowel 13 is fixed to the stator 5 and is electrically conductive. 14 is a flexible wiring board for connecting the signal of the open switch 2 to the drive circuit, and is soldered to the end of the open switch 2 and the stator 5.

Another role of the release switch lever 4B is to prevent the rotating ring 4 from coming off the cam plate 1. This is because the rotary ring 4 and the cam plate 1 are attached by the bayonet method as described above, and if the rotary ring 4 rotates more than a certain amount, they will come off. Therefore, stator 5
By incorporating the stator 5, the end face 5C of the stator 5 serves as a stop for the release switch lever 4B to prevent the bayonet from coming off.

Further, the rotation stop dowel 4C of the rotating ring 4 is another stopper for the rotating ring 4, and similarly to the above, the end face of the stator 9 prevents the bayonet from coming off. That is, by assembling the rotary ring 4 and then assembling the stator 5 and the stator 9, the rotary ring 4 will not come off the cam plate 1. In other words, the end face 5 of the stator 5
C and the end face of the stator 9 also serve as a rotation limiting member that mechanically prevents the rotating ring 4 from over-rotating.

The stators 5.7, 9.11 have connecting portions 5B, 7B, and 9B that form magnetic paths with the comb-shaped magnetic pole portions 5A, 7A, 9A, and IIA that face the rotor 8.

11B.

The stators 5.7 are magnetically connected by connections 5B, 7B to form one phase. Stator 9.11 likewise forms one phase. Each phase has an excitation coil 6.10
has. That is, this embodiment shows a case where a two-phase stepping motor is used.

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

The stators 5, 7, 9.11 are positioned and assembled by the pillars ID and IE of the cam plate 1, respectively. Connection part 5
B, 7B, 9B, IIB are stator 5 by press processing.
, 7, 9, and 11 are made by bending a part of them, but due to the processing precision, it is impossible to bring the two connecting parts into close contact.

That is, since the stators 5, 7, 9, and 11 are positioned by the pillars ID and IE provided on the cam plate 1, it is impossible to process the connecting portions so that they are in close contact with each other.

Therefore, as shown in FIG. 3, the dimensions are determined in advance so that a gap is created at the connecting portion. This prevents the connection portion from becoming tight and preventing correct positioning of the stator due to the struts ID and IE. However, from the viewpoint of magnetic properties, there is an air gap between the stators.
This increases magnetic resistance, which causes deterioration of motor characteristics. Therefore, as shown in FIG. 4, magnetic saturation can be suppressed by filling this gap with a magnetic material 16. The magnetic material 16 is preferably in the form of particles or liquid of soft magnetic material such as iron or ferrite, or in a mixture thereof with an adhesive or the like.

The rotor 8 is molded from a plastic magnet, and the shaft 8C and pinion gear 8B are also molded integrally. This not only makes it possible to create coaxiality between the shaft 8C and the magnet 8D with high precision, but also provides a dowel (or recess) 8A on the end face of the magnet 8D, and if magnetization is performed using this dowel 8A as a reference, the magnetic pole The positional relationship between the position and the pinion gear 8B can be guaranteed with high accuracy. As a result, when the rotor 8 is assembled into the stator, by setting the turbo 8A to a predetermined position, the position (angle) of the rotary ring 4 is also determined, and it is not necessary to make fine adjustments to the open position of the aperture blades 3. Accuracy can be guaranteed.

An excitation coil 6.10 is installed between the stator 5.7 and the stator 9.11, respectively.

The winding terminal of the excitation coil 6.10 passes through the stator and the hole 11, is drawn out to the upper surface of the base plate 12, and is connected to a printed wiring board or flexible wiring board (not shown). Further, as shown in FIG. 1, the base plate 12 has a bearing 12A for the rotor 8, and supports the rotor 8 rotatably. The base plate 12 is the pillar 10 of the cam plate 1. Positioned and installed by IE.

As shown in FIG. 1, in an electric drive exposure adjustment device configured by integrally incorporating a stepping motor and an aperture device, the stepping motor section is connected to the excitation coil 6.
．． When a current flows through 10, the rotor 8 and the magnetic pole part 5
A, 7A.

By generating repulsive force and attractive force in 9A and IIA,
A rotor 8 rotatably supported by a shaft rotates. The amount of rotation of the rotor 8 is determined by a combination of turning on and off the energization of the excitation coil, similar to a general stepping motor. Energization of the rotor 8 is started after confirming the state of the open switch 2.

If the open switch 2 is on and the aperture blades 3 are closed, the rotor 8 is energized in the direction in which the aperture blades 3 are opened, and this continues until the open switch 2 is turned off. It is only when the open switch 2 is turned off and the aperture blades 3 are in the open state that electricity is applied in the direction in which the aperture blades 3 are narrowed down.As the rotor 8 rotates a certain amount in the direction in which the aperture is narrowed down, the rotor 8 is molded integrally with the rotor 8. The rotary ring 4 meshed with the pinion gear 8B rotates. As the rotating ring 4 rotates, the aperture blades 3 are also operated by the dowels 3B. The dowel 3A of the aperture blade 3 operates within the cam groove IA of the cam plate 1, controls the position of the aperture blade 3, and determines the aperture diameter.

Exposure is performed once the aperture aperture is determined. after that,
The aperture blades 3 are returned to the open state again, and the open switch 2
Confirmation is made and all operations are completed.

Next, the assembly procedure will be explained.

FIG. 5 shows a jig 15 for assembling the aperture blades 3. The jig 15 has a reference surface for receiving the cam plate 1, and a pin 15A having a conical tip that fits into a through hole IH provided in the cam groove IA of the cam plate 1.

When the cam plate 1 is set on the jig 15, the conical pin 1
5A enters through hole IH. Next, dowel 3 of aperture blade 3
The conical recess A is aligned with the conical pin 15A of the jig 15 and assembled. This determines one point where the aperture blade 3 will be installed, so use this point as a fulcrum and attach the dowel 3B.
The aperture blades 3 may be moved to a position where the aperture blades 3 are aligned with the holes 4E of the rotating ring 4. After the position of the aperture blade 3 is determined, the rotating ring 4 is assembled. At this time, the claw portion IB of the cam plate 1 comes to the position of the notch portion 4A of the rotating ring 4. here,
The cam plate 1 is removed together with the rotating ring 4 from the jig 15, and the rotating ring 4 is rotated. Then, cam plate 1
Since the positions of the claw part IB and the notch part 4A of the rotary ring 4 are misaligned, the rotary ring 4 cannot be removed from the cam plate 1. After this, the stator 5.9 is assembled in accordance with the column ID and IE. By incorporating the stator 5.9, the bayonet mechanism between the rotating ring 4 and the cam plate 1 will not come apart due to the release switch lever 4B and rotation stopper 4C of the rotating ring 4.

After doing this, the release switch 2 is assembled into the cam plate 1. The cam plate 1 has the shaft IF of the open switch 2 and the rotation stopper I.
G is integrally molded. After installing the open switch 2, the rotating ring 4 is rotated to open the aperture blades 3. Then, the dowel 8A of the rotor 8 is set to a predetermined position and assembled, and the gear portion 4D of the rotary ring 4 and the binion gear 8B of the rotor 8 are engaged.

On the other hand, the base plate 12 and the stator 7.11 are fixed in advance, and the excitation coil 6.10 is connected to the connection parts 7B and 11B.
Incorporate. This subunit is installed next to the rotor 8. At this time, as already explained, if the air gaps between the connecting portions 5B and 7B, and between the connecting portions 9B and IIB pose a problem in terms of motor characteristics, the magnetic material 16 is filled between them. This may be applied to the connecting portions 5B and 9B before assembling the subunit.

Finally, pillar 10. The tip of the IE, that is, the portion protruding from the base plate 12 may be fixed by hot welding, adhesive, or the like. This can be accomplished by connecting the terminal of the excitation coil 6.10, the open switch 2, and the stator 5 to the drive circuit using a lead wire, a printed wiring board, a flexible wiring board, or the like.

Although the assembly procedure has been described above, there are no steps to make adjustments, and the assembly can be completed by sequentially assembling according to a predetermined procedure.

[Effects of the Invention] As explained above, according to the present invention, the shaft for attaching the release switch and the rotation stopper are integrally molded in a part of the cam plate, so the number of parts is reduced and the cam plate is integrally fixed. This eliminates the need for conventional heat caulking, reduces assembly man-hours, and forms open switch dowels as electrodes in part of the stepping motor stator, eliminating the need for additional parts and significantly reducing assembly costs. Cost reduction becomes possible. Furthermore, unlike conventional technology, the switching position is not unstable due to the wobbling of the switch pedestal, which occurs when the switch pedestal is provided separately, so the quality is stable and This has the effect of improving quality.

[Brief Description of the Drawings] Fig. 1 is an exploded perspective view showing one embodiment of the present invention, Fig. 2 is an enlarged perspective view showing an example of the assembly of the open switch shown in Fig. 1, and Fig. 3 is the same. FIG. 4 is an enlarged sectional view showing the connection part of the stator, FIG. 5 is a perspective view showing an example of the aperture blade assembly process in FIG. 1, and FIG. 6 is an enlarged sectional view. It is. 1...Cam plate IF...shaft 1G...rotation stopper 2...release switch 3...aperture blade
4...Rotating ring 4B...Release switch lever 5...Stator 13...Release switch dowel Fig. 2 Fig. 3 Fig. 5

Claims (1)

[Claims] An electromagnetic drive exposure adjustment device that uses a stepping motor as a driving source to open and close light-shielding aperture blades provided between a cam plate and a rotating ring, comprising an open switch that detects an open state of the aperture blade, and A shaft and a rotation stopper for the release switch are formed integrally with a part of the cam plate, and a part of the rotation ring has an release switch lever and a rotation stopper for the stepping motor. Electromagnetic drive exposure amount adjustment characterized in that a part of the stator is provided with an opening switch dowel that is electrically conductive with the stator and comes into contact with the opening switch when the aperture blades are narrowed down. Device.