JP2591633B2 - Power supply device for electromagnetically driven shutter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device used for an electromagnetically driven shutter provided in a camera for photographing or the like.

"Conventional technology" There are various types of electromagnetically driven shutters.
One example is shown in FIG. 5 and FIG.

This conventional shutter has a rotating body provided with a permanent magnet 11.
The shutter blades 14 and 15 are driven to open and close by an electromagnetic actuator composed of 12 and an electromagnet 13.

The rotating body 12 is rotatably mounted on a support shaft 16 provided on the main plate. The rotating body 12 includes yokes 17 and 18 integrally arranged on both sides of the permanent magnet 11, and a tongue-shaped arm formed obliquely. 19 and a balance waist 20 are provided.

The rotating body 12 has a first rotating position in which the tongue arm 19 abuts a stopper 22 having an elastic material 21 therearound, and a second rotating position in which the tongue arm 19 rotates clockwise from the first rotating position and abuts the stopper 23. Rotationally displaces between the rotation position.

Further, a blade drive shaft 24 provided on the tongue arm 19 of the rotating body 12 is loosely fitted in an elongated hole interlocking with each of the shutter blades 14 and 15, and the drive of the blade drive shaft 24 causes the shutter blade 14 to rotate. With the blade rotation shaft 25 as a support shaft, the shutter blades 15 respectively rotate with the blade rotation shaft 26 as a support shaft, and the openings 14a, 15a of the shutter blades 14, 15 open and close the aperture 27.

Further, the rotating body 12 and the electromagnet 13 constitute an electromagnetic actuator. The electromagnet 13 includes left and right legs 28a and 28b.
, And an electromagnetic coil 29 provided on the right leg 28b, and the power is supplied from power supply terminals 31a and 32b provided on a part of the bobbin 30. Electromagnetic drive Shiyatta the above configuration, during normal (when not in use), maintaining the rotating body 12 is a rotation position indicated by the angle line A _1, a first rotational position which has closed the Shiyatta blades 14, 15 It has become.

The first rotation position A ₁ is a suction force of the yoke 17 with respect to balance position A ₀ (left leg 28a, a yoke 18 for the right leg 28b
A position just right rotation rotation angle theta ₁ the suction force are balanced position) of.

When power is supplied to the electromagnet 13, a magnetic pole is generated on the end face of the core leg,
The magnetic pole of the yoke 17 repels the magnetic pole of the left leg 28a. Similarly, the magnetic pole of the yoke 18 repels the magnetic pole of the right leg 28b, and the rotating body 12
From the rotational position A ₁ toward the second rotation position A ₂ to rotate.

By this rotation, the shutter blade 14 starts turning left and the shutter blade 15 starts turning right. After turning the approach distances L ₁ and L ₂ , the opening of the aperture 27 starts.

When the rotating body 12 stops feeding of the electromagnet 13 before reaching the second pivot position A ₂ is by the suction force due to the magnetic poles of the yoke 17, 18 on the core leg end surface became non-magnetized, the rotating body
12 is rotated back toward the first rotational position A ₁ from its position, closes before Shiyatta blades 14 and 15 are fully opened. In this case, it operates as a program shutter in which the shutter blades 14 and 15 are also used as apertures.

When the power supply of the electromagnet 13 is continued, the rotating body 12
Rotated until it hits, when Shiyatta vanes 14 and 15 in the second rotational position A ₂ is fully opened state shown in FIG. 6, to stop the feeding of the electromagnet 13 in this fully opened state, similarly to the above yoke 1
The rotating body 12 returns and rotates by the attraction force of the magnetic poles 7 and 18, and the shutter blades 14 and 15 are closed.

"Problems to be Solved by the Invention" The electromagnetically driven shutter as described above is a shutter blade 1
From the fifth view of a state in which 4 and 15 are closed, when the driving Shiyatta opening, a predetermined level or more feeding s pressure V ₁ electromagnet
13 needs to be supplied, the rotating body 12 is moved to the first rotating position.
During pivoting from A ₁ to the second rotation position A ₂ have the feeding s pressure V ₁ is feed to the electromagnet 13.

However, once the rotating body 12 is driven, it rotates sufficiently without requiring a driving force as much as the initial rotation.
The feeding s than continue to that feeding with pressure V ₁ Shiyatta opening operation is very fast, is particularly difficult to stabilize the programmed Yatta operation in small diameter aperture.

To solve this problem, feed people but to delay the feed was Shiyatta operate at voltage V lower level feeding s pressure V ₂ compared to ₁ is thought, from the beginning of the feed with a power feeding s pressure V ₂ is The rotation start of the rotating body 12 may become unstable, or the rotating body 12 may not rotate and the shutter may not open.

"Means for solving the problems" The present invention has been developed in view of the above problems,
In an electromagnetically driven shutter comprising an electromagnetic actuator having a permanent magnet displaced between a first position and a second position by a magnetic action of an electromagnet and a shutter which opens and closes in conjunction with the displacement of the permanent magnet, the shutter is closed. the period from the rest position to the start and at least openings are driven at a predetermined level of voltages V _1, thereafter be provided with a power supply control means for feeding the electromagnets with a voltage V ₂ lower than the voltages V ₁ level A power supply device for an electromagnetically driven shutter characterized by the following.

Since up to the point immediately before or starts to open "work for" Shiyatta starts opening to be electromagnets powered by the voltage V ₁ of the predetermined level, the permanent magnet starts toward the second position from the first position with a sufficient drive torque Activate the shutter.

When Shiyatta came time before or starts opening begins to open, feeding s pressure of the electromagnet is changed to a low level voltage V ₂ than the voltage V _1, thereafter electromagnet Shiyatta powered by the voltage V ₂ is opened.

Therefore, the shutter operation does not become faster than necessary,
Also, the initial operation of the shutter is ensured.

"Example" Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to the above-mentioned conventional electromagnetically driven shutter, and FIG. 1 shows a state immediately before the shutter starts to open. FIG. 2 is a partially enlarged sectional view showing a part of the shutter.

In these figures, 15b is a small hole formed in the shutter blade 15. 50 is a light source such as a light emitting diode,
Reference numeral 51 denotes a photodetector using a photodiode or the like, which is arranged at a position where the small hole 15b passes just before the shutter blades 14, 15 start opening the aperture 27, and a photocoupler together with the small hole 15b. It constitutes.

This photocoupler is connected to a power supply control circuit (not shown).

The power supply control circuit starts operating in accordance with the shutter operation, and as shown in the time chart of FIG. 3, the voltage V ₁ at a predetermined level until the detection signal P is input from the photocoupler.
Is applied to the electromagnet 13 and after the detection signal P is input, the voltage V ₁
Certain low level voltage V ₂ as compared to a configuration is applied to the electromagnet 13.

3 (a) shows the feed voltage, FIG. 3 (b) shows the detection signal of the photocoupler, and FIG. 3 (c) shows the shutter blade 14,
15 indicates the aperture characteristics, and the symbol L ₀ shown in the figure is the shutter blade 1
Approach distance of 4, 15, S ₁ is the start position of Shiyatta opening, S ₂ is the fully open position of Shiyatta, T is the reference time used to adjust Shiyatta operation, t denotes time.

The electromagnetically driven shutter configured as described above is used until the shutter blades 14 and 15 start to open, that is,
While 14 and 15 are run-up started, because the electromagnet 13 is powered by the voltage V _1, rotating member 12 is started from the first rotational position with sufficient driving torque.

When run-up until just before the Shiyatta blades 14 and 15 begin to open, the photocoupler outputs a detection signal P detects the small hole 15b, changes the output voltage of the power supply control circuit responsive to the detection signal P to V ₂ from V ₁ and, the electromagnet 13 is powered by the voltage V _2.

Shiyatta blades 14 and 15 from the beginning to open the aperture 27, Shiyatta vanes 14 and 15 is fed with a said voltage V ₂ regardless of whether or not fully opened.

As a result, the activation of the shutter blades 14 and 15 is ensured, and the opening operation (operation between S _{1 and} S ₂ ) of the shutter blades 14 and 15 can be set to an appropriate speed.

To be specific, by changing the voltage V ₂ as V ₂ a, V ₂ b, V ₂ c, the opening characteristics of Shiyatta blades 14, 15 a, b, so change as c, It is determined the voltage V ₂ appropriately, the most preferred Shiyatta operating speed.

The adjustment of the shutter operation speed can be easily performed by using a well-known diaphragm area measuring instrument 52 and an oscilloscope 53 as shown in FIG. In this figure, reference numeral 54 denotes the above-described electromagnetically driven shutter, and reference numeral 55 denotes the above-described photocoupler.

The oscilloscope 53 displays a detection signal P of the photocoupler 55 and a voltage curve V corresponding to the opening area of the shutter blades 14 and 15 (operation between S _{1 and} S ₂ ). determining more the voltage level of the voltage V ₂ and the reference time T. The reference time T is a time from when the shutter blades 14 and 15 start to open the aperture 27 to when the shutter blades 14 and 15 reach a time immediately before the shutter 27 fully opens.

According to the measurements by the inventors, the time Q at which the voltage curve V passes the reference time T is about 10% of the maximum value Vmax of the voltage curve V.
By adjusting the operating speeds of the shutter blades 14 and 15 so as to make them smaller only, it has been found that a high-precision program shutter can be obtained.

From this measurement result, the level of the feed voltage V ₂ is Vmax−ΔV
(Approximately 1% according to the above measurement), thereby obtaining an appropriate shutter operation speed and a product having uniform performance.

As described above, the embodiment of the present invention has been described. However, the small hole 15b formed in the shutter blade 15 is provided in the other shutter blade 14 to constitute a photocoupler, or the small hole 15b is reflected instead of the small hole 15b. A photocoupler utilizing this reflection is provided, and a magnetic sensor 56 is provided as shown in FIG. 1 to output a detection signal P. Also, when the shutter blades 14 and 15 start to open, Can be changed arbitrarily, for example, by detecting the light passing through the shutter and outputting the detection signal P.

In addition, the present invention is not limited to the electromagnetically driven shutter having the above-described configuration, and can be applied to other similar electromagnetically driven shutters.

“Effects of the Invention” As described above, the power supply device according to the present invention is provided at least immediately before or at the time when the shutter starts to open.
Since power the electromagnet with a voltage V ₁ of the predetermined level, Shiyatta activation is ensured, also, the subsequent the Shiyatta begins to open for the feeding at a low level voltage V ₂ than in the voltages V _1, moderate is Shiyatta operating speed A high-performance electromagnetic drive shutter adjusted to

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an electromagnetically driven shutter provided with a power supply device according to the present invention, FIG. 2 is a partially enlarged cross-sectional view of the shutter, and FIGS. 3 (a) and (b). (C) is a time chart showing an output voltage of the power supply control circuit, a detection signal of the photocoupler, and an opening characteristic of the shutter blade 1, FIG. 4 is a simplified diagram of a diaphragm area measuring device and an oscilloscope showing adjusting means of the shutter operation speed, 5 and 6 are configuration diagrams showing a conventional example of an electromagnetically driven shutter. FIG. 5 shows a shutter closed state, and FIG. 6 shows an open state. 11 Permanent magnet 12 Rotating body 13 Electromagnet 14, 15 Shutter blade 15b Small hole 17, 18 Yoke 22, 23 Stopper 27 Aperture 50 Light source 51 Light receiving vessel

Claims (2)

(57) [Claims] 1. An electromagnetically driven shutter comprising: an electromagnetic actuator having a permanent magnet displaced between a first position and a second position by a magnetic action of an electromagnet; and a shutter which opens and closes in conjunction with the displacement of the permanent magnet. , Shiyatta is at voltages V ₁ during the predetermined level to start at least the opening is driven from a rest position of the closure, it thereafter feeding control for feeding the electromagnets with a voltage V ₂ lower than the voltages V ₁ level A power supply device for an electromagnetically driven shutter, comprising: 2. A shutter for opening and closing a shutter blade, and a detecting portion comprising a small hole or a light reflecting portion is provided on the shutter blade. The detecting portion passes when the shutter starts to open or immediately before the shutter starts to open. in position, comprising a photo-coupler configured with this detector, the range of the optocoupler in response to the detection signal output patent the feeding control means for varying the voltages V ₁ to V ₂ according (1)
A power supply device for an electromagnetically driven shutter described in the paragraph.