JPH01101527A - Electromagnetically driven exposure adjusting device - Google Patents

Abstract

PURPOSE:To reduce the number of components and the man-hour of assembling processes by bending a part of a stator of a stepping motor and forming a connection part forming a magnetic path as an iron core. CONSTITUTION:Stators 5, 7, 9, 11 have comb-line magnetic pole parts 5A, 7A, 9A, 11A opposed to a rotor 8 and connection parts 5B, 7B, 9B, 11B acting as iron cores forming magnetic paths. The stators 5, 7 are magnetically connected by the connection parts 5B, 7B to form a phase and the stators 9, 11 similarly form one phase. Respective phases have exciting coils 6, 10. Since it is unnecessary to form an individual member as an iron core, the number of components and the man-hour of assembling processes can be reduced.

Description

[Detailed Description of the Invention] [Public Expenses for Industrial Use] The present invention relates to an electromagnetically driven exposure amount adjusting device, and more specifically, it relates to an electromagnetic drive exposure adjustment device, and more specifically, to a device such as a shutter or aperture device installed in a still camera, a video camera, or an interchangeable lens thereof. The present invention relates to an exposure amount adjustment device.

[Prior Art] In a conventional exposure amount adjusting device of this type, the stator of the stepping motor and the iron core serving as the magnetic path are separate members.

[Problems to be Solved by the Invention] As mentioned above, in the conventional technology, the stator of the stepping motor and the iron core, which serves as the magnetic path, are made of separate members.
The iron core and stator, which form the magnetic path, had to be connected using screws.

Therefore, there are problems in that the number of parts increases, the assembly process becomes complicated, and the cost 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 a light-shielding aperture blade provided between a cam plate and a rotating ring, the stepping snow
A part of the stator was bent to provide a connection part that served as an iron core to form a magnetic path, and an excitation coil was provided to surround the connection part.

Further, if necessary, a soft magnetic material (magnetic material) such as Fe50° is filled in the gap between the facing portion of the bent connection portion of one stator and the bent connection portion of the other stator.

[Function] According to the present invention, since a part of the stator of the stepping motor is bent and has a connection part that forms a magnetic path as an iron core, there is no need to provide a separate member as an iron core, and the number of parts and assembly man-hours are reduced. is reduced, and the efficiency of the stepping motor is also improved. Also, in the assembly process,
A gap is formed between the upper and lower stators, which deteriorates the magnetic efficiency. Therefore, by filling the gap with a soft magnetic material such as Fe504, an increase in the magnetic resistance of the stator magnetic circuit can be avoided.

[Example] FIG. 1 is an exploded perspective view showing one 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
The outer periphery of the rotary ring 4 has a claw portion IB for forming a bayonet mechanism. This claw portion IB is provided at three or more locations.

IC is a bearing that rotatably supports the rotor 8. I
D is a support for incorporating the stator 5 and excitation coil 6;
Similarly, IE is a support for incorporating 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 is moved by the dowel 3B of the aperture blade 3 which is connected to the hole 4E of the rotary ring 4. At this time, the dowel 3A (see Fig. 5) on the opposite side of the aperture blade 3 to the dowel 3B moves within the cam groove IA of the cam plate 1, so the aperture aperture surrounded by the aperture blade 3 opens and closes. Do this.

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 if the aperture blades 3 do not operate or close 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 and rotation stopper IG are integrally molded with the cam plate 1, high positional accuracy can be achieved. Open switch dowel 13
is fixed to the stator 5 and is electrically connected. 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 rotating ring 4 and the cam plate 1 are attached by the bayonet method as described above, and if the rotating ring 4 rotates more than a certain amount, it 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 comb-shaped magnetic pole portions 5A, 7A, 9A facing the rotor 8.

It has connection parts 5B, 7B', 9B, and IIB that serve as iron cores that form a magnetic path with 11A.

The stators 5 and 7 are magnetically connected by connecting portions 5B and 7:B to form one phase. The stators 9 and 11 similarly form one phase. Each phase has an excitation coil 6.1
has 0. 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, 11B 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 IH 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 the stator from being correctly positioned by the support columns ID and IE. However, 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 this gap with a magnetic material 16. This magnetic material 1
6 is preferably a particle or liquid of soft magnetic material such as iron or ferrite, or 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 dowel 8A to a predetermined position, the position (angle) of the rotating ring 4 is also determined, and the opening position of the aperture blade 3 does not need to be finely adjusted. Accuracy can be guaranteed.

W5 magnetic coils 6.10 are incorporated between stator 5.7 and stator 9.11, respectively.

The winding ends of the excitation coils 6.10 pass through the holes in the stators 7 and 11, are drawn out onto the upper surface of the base plate 12, and are 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 positioned and attached by the pillars ID and IE of the cam plate 1.

As shown in FIG. 1, in an electromagnetic drive exposure adjustment device configured by integrally incorporating a stepping motor and an aperture device, the stepping motor section is connected to an excitation coil 6.10.
When a current flows through the rotor 8 and the magnetic pole parts 5A and 7,
A.

By generating repulsive force and attractive force at 9A and 11^,
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. Only after the open switch 2 is turned off and the aperture blades 3 are in the open state is electricity applied in the direction in which the aperture blades 3 are narrowed down. As the rotor 8 rotates by a certain amount in the narrowing direction, the rotating ring 4 that meshes with the pinion gear 8B formed integrally with the rotor 8 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. Thereafter, the aperture blades 3 are returned to the open state, confirmation is made by the open switch 2, 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
Align the conical recess A with the conical pin 15A of the jig 15 and install it. This will determine one point at which the aperture blade 3 will be installed, so use this as a fulcrum and insert 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 that, the stator 5゜9 is assembled in accordance with the pillars ID and IE. By incorporating the stators 5 and 9, the bayonet mechanism between the rotary ring 4 and the cam plate 1 is activated by the release switch lever 4B of the rotary ring 4 and the rotation stopper 4C. , it will not come off.

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 with each other.

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 is done before installing the subunit.
Just apply it to part B.

Finally, pillar 10. The tip of the IH, that is, the portion protruding from the base plate 12 may be fixed by heat welding or the like. later,
The terminal of the excitation coil 6.10, the open switch 2, and the stator 5 may be connected to the drive circuit using lead wires, 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, since a part of the stepping motor is bent and has a connection part that forms a magnetic path as an iron core, there is no need to provide a separate member as an iron core, and parts The number of parts and assembly man-hours are reduced, and in terms of assembly, it can be assembled from one direction and automatic assembly is possible, resulting in significant cost reductions.

[Brief explanation of the drawing]

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 similarly shows the connection part of the stator. FIG. 4 is an enlarged perspective view, FIG. 4 is an enlarged sectional view, FIG. 5 is a perspective view showing an example of the process of assembling the aperture blades of FIG. 1, and FIG. 6 is an enlarged sectional view. 1...Cam plate, 3...Aperture blade, root, 4...
・Rotating ring, 5.7, 9.11... Stator, ・ 5B, 7B, 9B, IIB... Connection part, 6.10...
- Excitation coil, 8... rotor, 16... magnetic material. Figure 2 Figure 3

Claims (1)

[Claims] 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, a portion of the stator of the stepping motor is bent and used as a magnetic core. 1. An electromagnetically driven exposure amount adjusting device, comprising a connecting portion forming a path, and an excitation coil provided around the connecting portion.