JPS6019646B2 - Electromagnetic mechanism for camera release - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an electromagnetic mechanism used as a drive source for the shutter operation of a camera, and the armature is canceled by magnetic flux generated by an excitation coil to cancel the attraction of the armature by a permanent magnet, thereby performing the trigger operation. This invention relates to an electromagnetic mechanism for release.

The electromagnetic mechanism for performing the release operation in electrically controlled cameras is required to be extremely compact and operate quickly, and it is also necessary to minimize power consumption, so various configurations have been proposed. has been done. The applicant of the present invention previously filed the "Patent Application No. 14360-1983"
(Refer to Special Publication No. 50-109723), we proposed an electromagnetic mechanism for electric wires in which the magnetic flux of a permanent magnet is canceled out by the magnetic flux generated by an excitation coil to release the armature from adsorption. In this type of electromagnetic mechanism, it is necessary to flow a large amount of current in pulses to the excitation coil to perform the shutter operation, and this requires the accumulated charge in the capacitor, which is pre-charged by the power battery, to be simultaneously transferred to the excitation coil. A discharging circuit configuration is used. In other words, the electromagnetic mechanism of the above type is difficult to directly drive with a small capacity battery built into a camera, etc., such as a mercury battery or a silver battery. A method of discharging the excitation coil is used, which is accompanied by a certain time delay for charging the capacitor. If the camera is operated by an electromagnetic mechanism like this, there will be no problem during normal shooting in the evening, but if you use a motor drive etc. for high-speed continuous shooting, the capacitor will not be charged in time and there will be a problem. In order to compensate for this, it is necessary to increase the power supply voltage to shorten the charging time, which causes inconveniences such as space constraints and increased power consumption for military 20 source batteries. there were. The present invention provides a release electromagnetic mechanism that eliminates the drawbacks of the conventional electromagnetic mechanisms as described above, and its purpose is to be able to operate effectively with a small capacity power source and to provide high-speed continuous operation. To obtain an electromagnetic mechanism that is small and consumes little power and can sufficiently respond to leakage operations during photographing.

That is, in the electromagnetic mechanism of the present invention, the armature for release operation is attracted and held by the magnetic flux from the permanent magnet disposed in a part of the yoke, and the magnetic flux generated by energizing the excitation coil disposed in the yoke is caused by the permanent magnet. In the electromagnetic mechanism that cancels the magnetic flux and releases the armature, a bypass magnetic path made of a semi-hard magnetic material is provided between the poles of the permanent magnet, a second excitation coil is disposed in this bypass magnetic path, and a release mechanism is provided. The release electromagnetic mechanism includes means for demagnetizing the semi-hard magnetic material at the time of reset. The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of an electromagnetic mechanism for a leash according to the present invention. In the figure, reference numeral 1 denotes an armature made of a soft magnetic material, and its attraction/release operation drives a release mechanism (not shown). 2 is a yoke made of a soft magnetic material.

3 is a permanent magnet fixed to a part of the yoke 2; 4 is a bypass magnetic path made of a semi-hard magnetic material disposed between both poles of the permanent magnet 3; 2, 3, and 4 are integrally constructed.

5 is biased by a biasing spring of armature 1 in the direction of the arrow.

6 is an excitation coil wound on one arm (or both arms) of the yoke 2, and 7 is an excitation coil wound on the bypass feeder, and a current is passed through these to obtain magnetomotive force electromagnetically. .

Permanent magnets 8 and 9 are brought close to both ends of the bypass magnetic path to perform an extinguishing action when the electromagnetic mechanism is reset.

10 is a holding member for permanent magnets 8 and 9, and a reset member composed of 8, 9, and 10 is configured to be movable in the direction of the arrow.

FIG. 2 is a curve diagram showing an example of the magnetization characteristics of the semi-hard magnetic material constituting the bypass magnetic path in the electromagnetic mechanism of the present invention. In the figure, the intersection between the horizontal axis (magnetizing force H) and the curve represents the coercive force, and the intersection between the vertical axis (magnetic flux density B) and the curve Br, 1 Br represents the residual magnetism. In the configuration shown in FIG. 1, when the armature 1 is apart from the yoke 2, the strength of the magnetic field applied by the permanent magnet 3 to the bypass magnetic path 4 made of a semi-hard magnetic material is determined by the coercive force as shown by HB in FIG. The strength of the magnetic field HA applied to the bypass passage when the armature is attracted to the yoke is set to be smaller than the coercive force HE. In other words, at this time HA < Sunsaku HB
The conditions of '11 are satisfied.

Also, when resetting, the permanent magnets 8 and 9 of the reset member
When the magnetic field reaches the position shown in the first diagram, the strength HR of the magnetic field applied to the bypass magnetic path 4 by these 8 and 9 becomes a value larger than the retention force of the semi-hard magnetic material and smaller than the magnetic field strength. It is set as follows. In other words, in this state, the following condition is established: -day<HR<-date [2].

In the electromagnetic mechanism of the present invention, with the configuration shown in Fig. 1, formula {1} is satisfied when the armature is attracted (after reset), and formula '2} is satisfied when the armature is reset and the holding force of the semi-hard magnetic material. It is necessary to construct the bypass magnetic path as shown in the figure using a semi-hard magnetic material. Next, the operation of the electromagnetic mechanism for leasing according to the present invention will be explained. Figure 3 shows the states of the electromagnetic mechanism of the present invention at the time of reset (Figure a), at the time of inputting the release signal (Figure B), and at the time of release (Figure C), and their equivalent magnetic circuits b', b', and c'. FIG. In the figure, the same parts as in FIG. 1 are designated by the same reference numerals. In the equivalent circuit, Ra is the equivalent magnetic resistance of the armature 1, Ry is the equivalent magnetic resistance of the yoke 2, and Rg is the equivalent magnetic resistance of the attraction surface gap between the armature and the yoke, and these are connected in series with each other. Rm' is the equivalent magnetic resistance of the permanent magnet 3 disposed in a part of the yoke 2, and Um is the magnetomotive force of the permanent magnet. At the time of resetting, the armature is reset as shown in FIG. 3a, and at the same time, the permanent magnets 8, 9 of the resetting member come close to both ends of the bypass mechanism, apply a magnetic field to the semi-hard magnetic material, and then separate. As a result, the magnetic field generated by the permanent magnet 3 and excitation coil 7 cancels out the magnetism generated in the semi-hard magnetic material.
The equivalent magnetic circuit is shown by two constant voltage diodes (Zener diodes) ZD connected in a reverse sacrificial manner to each other as shown in Fig. 3 a'. Therefore, the equivalent magnetic circuit at the time of reset is shown in Fig. 3. It becomes like a'. As shown in the figure, the magnetic flux ■m generated by the magnetomotive force Um of the permanent magnet 3 flows only into the shunt on the yoke side and does not flow into the bypass magnetic path. Force F
．． is F. It is represented by E2 ticket sa-f ■.

Here, S is the attraction area of the gap between the armature and the yoke, M o is the magnetic permeability in vacuum, and f is the force of the spring biasing the armature. That is, in the reset state (Fig. 3a), sufficient magnetic flux flows toward the armature and yoke to maintain the state in which the armature 1 is attracted to the yoke 2, and the armature is attracted to the yoke against the external force f. . FIG. 3b shows a state in which the reset signal is input to the excitation coils 6 and 7, and FIG. 3' shows an equivalent magnetic circuit in this state.

In this state, an excitation current flows through the excitation coils 6 and 7 wound around the yoke and the bypass supply path, and as a result, as shown in Fig. 3M, in addition to the magnetic flux m due to the permanent magnet 3 on the yoke and armature side. Magnetic flux ■E flows in the opposite direction. Further, a magnetic field generated by the excitation coil 7 is generated in the bypass magnetic path, and this and the magnetic field generated by the permanent magnet 3 are generated in the same direction and are added together, and a magnetic flux (D) flows. That is, as the coercive force of the semi-hard magnetic material increases, this magnetic field becomes larger and magnetic flux begins to flow through the bypass magnetic path, and this circuit operates as a bypass magnetic path for the permanent magnet. Therefore, the equivalent magnetic circuit in this state is as shown in Figure 3b', where the semi-hard magnetic material is a diode D connected in one direction.
It is expressed as Therefore, the magnetic flux ■m caused by the permanent magnet 3 is shunted to the bypass magnetic path and is canceled by the magnetic flux ■E deflected by the excitation coil 6, and the attractive force F2 between the armature and the yoke is F2=2 [■m, one D+■E)〕2-
f side 2mm.

It becomes S.

When the attraction force F2 in the '4-type becomes (1), the armature is released from attraction from the yoke, thereby performing a release operation. FIG. 3C is a diagram showing the state after the release, in which the armature is separated from the yoke 2 by the force of the spring 5.

In Figure 3, '' is the equivalent magnetic circuit at this time, and the yoke and the
The equivalent resistance Rg' of the suction surface of the mature is shown in Figure 3 a and b above.
The value is higher than Rg in the case of . Therefore, most of the magnetic flux generated by the permanent magnet 3 flows through the bypass 4 made of a semi-hard magnetic material, and the semi-hard magnetic material acts as a permanent magnet. Rm' in FIG. 3C' is the equivalent magnetic resistance of this semi-hard magnetic material. Um' is the magnetomotive force.
The operating point of the semi-hard magnetic material in this state is shown in Figure 2.
This will be the point shown in . Therefore, if the reset permanent magnets 8 and 9 are brought close to both ends of the bypass magnetic path to cancel out the magnetic field of the semi-hard magnetic material, the magnetic field on the yoke and armature sides will become stronger, and the magnetic resistance of the attraction surface will change from Rg due to the IJ setting of the armature. Since the magnetic flux decreases to Rg, the magnetic flux from the permanent magnet 3 flows again into the magnetic path between the yoke and the armature, and the armature is reset. At this time, the strength HR of the magnetic field applied to the semi-hard magnetic material is 3<HR<
All you have to do is turn it into a reed for a day. As a result of the above, the electromagnetic mechanism returns to the state shown in FIG. 3a, and the equivalent magnetic circuit of the bypass circuit also becomes a Zener diode Z as shown in FIG. 3a'. Return to the state expressed by . In the embodiments shown in FIGS. 1 and 3, a magnetic field from a permanent magnet is used as the reset member, but in addition to this, the bypass magnetic path can be electrically extinguished by passing a current in the opposite direction through the excitation coil 7 for a short time. It goes without saying that it's okay to be kind.
As described above, in the release electromagnetic mechanism according to the present invention, by providing a bypass magnetic path made of a semi-hard magnetic material at both ends of the permanent magnet provided in a part of the yoke, the release current flowing through the excitation coil can be reduced. This makes it possible to reduce power consumption when the camera is in use, and to perform the camera release operation accurately during high-speed continuous shooting. Therefore, it is possible to create a device that provides excellent effects as an electromagnetic mechanism for cameras and the like, and the effects are great.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an example of an electromagnetic mechanism for magnetic wires according to the present invention, Fig. 2 is a curve diagram showing an example of magnetization characteristics of a semi-hard magnetic material, and Fig. 3 is an operation of the electromagnetic mechanism of the present invention. They are a configuration diagram and an equivalent magnetic circuit diagram for explanation. 1... Armature, 2... Yoke, 3... Permanent magnet,
4... Bypass magnetic path made of semi-hard magnetic material, 5...
... Spring, 6, 7 ... Excitation coil, 8, 9
...Reset permanent magnet, 10... Reset magnet support village. Figure 1 Figure 2 Crowded diagram

Claims (1)

[Claims] 1. A first yoke which has an armature attraction surface and which can be wound around at least one magnetic path of a yoke in which a part of a permanent magnet is disposed.
An electromagnetic mechanism that performs a release operation of an armature by flowing an excitation current through an excitation coil to cancel the magnetic flux caused by the permanent magnet, comprising: a bypass magnetic path made of a semi-hard magnetic material disposed between both poles of the permanent magnet; and a second excitation coil that can be wound around the bypass magnetic path, and an excitation current that is synchronized with the first excitation coil is caused to flow through the second excitation coil to perform a release operation of the armature. An electromagnetic mechanism for releasing a camera, comprising a reset mechanism that generates a magnetic field for canceling the magnetic flux flowing through the bypass magnetic path at the time of reset.