JPH02271602A - Electromagnetic actuator - Google Patents

Abstract

PURPOSE:To downsize the actuator mentioned in the title, reduce its consumption power and control three operations separately by a method wherein two electromagnets placed in parallel to each other and three attraction pieces are used while the respective electromagnets are turned ON/OFF. CONSTITUTION:Two electromagnets 3, 4 placed in parallel to each other are used to control respective parts wherein separating operation of a first attraction piece 5 is done by turning OFF one of the electromagnets 3, separating operation of a second attraction piece 14 is done by turning OFF the other electromagnet 4 and attraction operation of a third sucking piece 10 is done by turning ON both electromagnets 3, 4. Further at the time of attracting the third attraction piece 10, both electromagnets 3, 4 are activated to attract with total attraction of both so that attraction force of each electromagnet can be weak. Thus three operations can be separately controlled while the size of the apparatus need not be very large even if two electromagnets are used and increase in consumption power can be also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electromagnetic actuator that controls various parts by attracting and separating an attracting piece using an electromagnet.

Conventional technology Conventionally, one electromagnet is equipped with two suction plates, and one suction piece controls one operation, and the other suction piece controls two operations, thereby controlling a total of three operations. Tt, magnetic actuators are known. For example, when used in a camera's aperture control device, first the aperture starts to be narrowed down by the adsorption action of one of the adsorption pieces, and at the same time the mirror is raised (so that the object light reaches the film when shooting, and the object light reaches the film when not shooting). The mirror that reflects the light toward the finder is moved away from the optical path. Next, when the narrowing down reaches a desired value, the narrowing down is stopped by separating the other suction piece. In this way, the adsorption of two adsorption pieces,
Three operations, ie, start of narrowing down, mirror up, and stopping of narrowing down, were controlled by the separation operation.

Problem to be Solved by the Invention However, in this case, since two operations are controlled by one suction piece, the two operations are controlled simultaneously and cannot be operated separately. In the example of the aperture control of the conventional camera described above, it is not possible to perform an operation of narrowing down the aperture without raising the mirror, a so-called preview operation (confirming the subject image with the aperture closed down).

Therefore, a device may be considered in which an electromagnet for mirror-up control is provided separately from an electromagnet for aperture control.

However, using two electromagnets increases the size of the device,
The current consumption also increases; a problem arises.

However, if you reduce the number of turns of the electromagnet's coil or reduce the current, the electromagnet's attractive force will weaken, which is a problem.

To explain this problem in detail, the suction force may be small in order to keep the suction piece detached and maintained, but a large suction force is required during suction operation.

The number of turns and current of conventional coils are set according to the adsorption force required for this adsorption operation, and as mentioned above, if the number of turns or current of the coil is further reduced, the adsorption operation will no longer be possible. be.

An object of the present invention is to provide an electromagnetic actuator that is small in size, has low current consumption, and can control three operations separately.

Means for Solving the Problems In order to solve the above problems, the present invention comprises two electromagnets, each consisting of a coil core and a coil, arranged parallel to each other;
Of these two electromagnets, the first attraction piece receives only the attraction force of one of the electromagnets, the second attraction piece receives only the attraction force of the other electromagnet, and the third attraction piece receives the attraction force of both electromagnets.
It is characterized by having an adsorption piece of.

Function When one of the two electromagnets is turned off, the first adsorption piece moves away, and the other electromagnet is turned off.
As a result, the second suction piece moves away. Furthermore, by turning on both electromagnets, the third suction piece operates to attract. The operation of each suction piece controls the device corresponding to that suction piece.

Embodiment A case will be described in which the present invention is implemented as an actuator for aperture control and mirror drive control of a single-lens reflex camera.

1 to 4 sequentially show the normal release operation. First, the configuration will be explained with reference to FIG.

The coil (3) and the coil (4) are N magnets each having a coil core (1) and a coil (2) made of magnetic materials, and are arranged in parallel and fixed within the mechanism of the camera.

The suction piece (10) is a suction piece that controls the start of narrowing down the aperture, and is rotatably supported by a shaft (IOB) between the wall (11) and the coil core (1X2). The narrowing start lever (12) is rotatably supported by a shaft (12B) and is in contact with the suction piece (10) at a contact portion (12A). Therefore, coils (3) and (4) are energized,
When the suction piece (10) is attracted to the coil cores (1) and (2) and rotated clockwise, the abutment part (12A) of the narrowing start lever (12) is pushed by the suction piece (10) and rotates counterclockwise. rotate in the direction. This rotation of the narrowing start lever (12) releases the lock that prevents the narrowing of the aperture (not shown), and the narrowing starts. The spring (13) biases the narrowing start lever to rotate clockwise. This urging force is applied to the contact portion (12A
) to the suction piece (lO), and when the coil is not energized, the suction piece (10) is in a position where it abuts against the wall (11).

By the way, in order to attract a detached attracting piece, a larger attracting force is required than simply maintaining the attracted state. Therefore, in this embodiment, both coils (3) and (4) are energized, and the adsorption piece (10) is adsorbed with the adsorption force of both, so that even if the number of windings of each coil and the current are small, adsorption is possible. It is.

The suction piece (5) is a suction piece for mirror drive control, and is attached to the shaft (
5B) is rotatably supported.

The spring (6) urges the suction piece (5) to rotate clockwise. The mirror drive control lever (7) is rotatably supported by a shaft (7B), and also has a contact portion (7).
A) is in contact with the suction piece (5).

The spring (8) urges the mirror drive control lever (7) to rotate clockwise with a force stronger than the spring (6). The locking member (9) restricts the rotation of the mirror drive control lever (7), and is retracted in conjunction with the counterclockwise rotation of the aforesaid aperture start lever (12), thereby controlling the mirror drive control.・Enables clockwise rotation of the Am lever (7). If the locking member (9) is retracted and the coil (3) is de-energized, the bias of the spring (8) is stronger than the bias of the spring (6), so the lever for controlling the mirror drive (7) rotates clockwise. This rotation of the mirror drive control lever (7) disengages a mirror-up system (not shown) and starts mirror-up.

Figure 1 shows the initial state before release, where the suction piece (5)
It is locked by a locking member (9) so that the suction part (5A) of the coil core (1) comes into contact with the coil core (1).

The suction piece (14), the aperture stop lever (16), the spring (15) (17), and the locking member (18) are the suction piece (5), the mirror drive control lever (7), and the spring (6) (8). ) and the locking member (9), respectively, have similar configurations. When the locking member (18) is retracted and the coil (4) is de-energized, the narrowing stop lever rotates counterclockwise due to the biasing force of the spring (17).

This rotation engages a lock (not shown) that prevents the narrowing down, thereby stopping the narrowing down.

Note that the adsorption pieces (5), (10), and (14) are plates made of magnetic material, and the coil cores (1) (2) and the adsorption pieces (5) (1)
0) A closed magnetic path is formed by (14).

Therefore, the force that attracts the attraction piece (10) becomes relatively strong.

Next, the operation will be explained. FIG. 1 shows the initial state in which charging of each part is completed at the time of release. In this state, the aperture is locked and does not narrow down. Also, the mirror is lowered and reflects the subject light towards the viewfinder.

First, diaphragm control at the time of release will be described with reference to FIGS. 1 to 4. In this case, first coils (3) and (4)
) is energized. The magnetic flux generated by this is distributed between the coil cores (1) (2), the adsorption pieces (5) (10) (
14) and attempt to close, the suction piece (10) rotates clockwise and is suctioned to the coil cores (1) and (2).

Correspondingly, the aperture start lever (12) rotates counterclockwise to release the aperture travel system (not shown). Then, narrowing down is started. Also, in conjunction with the rotation of this narrowing start lever (12), the locking member (9) (1
8) is retracted, allowing rotation of the mirror drive control lever (7) and the aperture stop lever (16). However, the coil (3
) (4), the suction pieces (7) and (14) are both suctioned, and the mirror drive control lever (7) and aperture stop lever (16) still do not rotate (the second
figure).

After that, the power to the coil (3) is cut off. Then, as described above, the biasing force of the spring (8) causes the mirror drive lever (7) to rotate clockwise and the suction piece (5) to rotate counterclockwise. By this rotation of the mirror drive lever (7), a mirror up system (not shown) is unlocked, and the mirror is raised. At this time, since the coil (4) is energized, the attraction pieces (4) (10) are still attracted (FIG. 3). It should be noted that a very large adsorption force is not required to maintain the adsorption state, and it can be maintained only by the adsorption force of the coil (4).

During this time, the aperture continues to run, but the aperture control technique uses known aperture control techniques, for example, to obtain the aperture amount by counting encoder pulses, and when the aperture amount reaches the desired value,
Cut off the current to the coil (4).

Then, as described above, the aperture stop lever (16) is rotated counterclockwise and the suction piece is rotated clockwise due to the biasing force of the spring (17). Then, by rotating this aperture stop lever (6), a lock (not shown) is engaged to prevent the aperture from being apertured, and the aperture is stopped (FIG. 4).

After that, the shutter is controlled.

Further, a case will be described in which the current to the coil (3) is not cut off in the state shown in FIG.

In this case, close down the aperture without raising the mirror. At this time, as described above, when the aperture amount reaches the desired value, the coil (4) is de-energized and the aperture movement is stopped (fifth
figure).

In this state, the mirror is not raised, so the subject light passing through the lens is directed toward the viewfinder. In other words, it is possible to check the subject image with the desired narrowing down, or to preview it.

FIG. 6 is a block circuit diagram of a camera using this device.

In Fig. 6, the photometry start switch (Sl), release switch (S2), and preview switch (S3) are input terminals (IPI) (IF5) of the microcomputer (C), respectively.
(IF5). Note that the photometry start switch (Sl) and the release switch (S2) are operated by the same operating member; pushing the operating member one step turns the photometry start switch (Sl) ON, and pushing it further turns the release switch (S2) ON. do. The microcomputer CC) detects the state of this switch and performs calculations and controls each part according to a sequence according to the result.

A lens circuit (LE) is placed inside the lens and stores information about the lens. Lens information is input to the microcomputer (6) through the lens data bus. Photometric circuit (
Ll) has a light receiving element and outputs a digital value according to the output of the light receiving element to the microcomputer (C). The aperture pulse detection circuit (A) is a circuit, such as an encoder, that converts the aperture narrowing operation into a pulse output and outputs the pulse output.

The energization of the magnet (Mgl) is controlled by the conduction state from the collector to the emitter of the transistor (Ql), and while energized, the front curtain of the shutter is held by its attractive force, and when the energization is cut off, the front curtain moves. It has become. The magnet (Mg2) is an electromagnet whose energization is controlled by the conduction state from the collector to the emitter of the transistor (Q2), and which is composed of a core (1) that controls the movement of the shutter trailing curtain similarly to the magnet (Mgl). Further, the magnet (Mg4) is an electromagnet composed of a coil (4) and a coil core (2). This magnet (Mg3) (M
g4) is controlled by the conduction state from the collector to the emitter of the transistors (Q3) and (Q4), respectively. And transistors (QIXQ2) (Q3)
The base terminals of (Q4) are respectively connected to the output terminals (OPI) (OF2) (OF2) (OF2) of the microcomputer (C), and conduction between the collector and emitter is controlled by signals output from each output terminal.

Specifically, when a HIGH signal is output from the output terminal of the microcomputer (C) and the HIGH signal is applied to the pace terminal of the transistor connected to the output terminal, the signal from the collector to the emitter of that transistor is Continuity is turned on. Further, when a LOW signal is output, conduction is turned off. That is, magnet (Mg3) (M
The electromagnetic device of the present invention including g4) is controlled by signals from the output terminals (OF2) and (OF2) of the microcomputer (6).

In the above configuration, the operation of the microcomputer (6) will be explained with reference to FIGS. 7 and 8.

FIG. 7 shows a sequence performed when the photometry start switch (Sl) is turned on. Photometry start switch (Sl)
When is turned on, the main routine shifts to this routine. First, in step (100), the lens circuit (L E
), from the lens data (maximum aperture AVO, minimum aperture AV
MAX, etc.). In step (101), a signal to start photometry is sent to the photometry circuit (Ll) to start photometry, and in step (102) photometry data is read. Based on these lens data and photometric data, step (
Exposure calculation is performed in step 103), and the control aperture AV and shutter speed TV are calculated. Further, in step (104), the aperture control amount ΔP and the shutter speed T are calculated. At this time, ΔP is calculated based on the following equation.

△P=AV-AVO Next, in step (105) release switch (S2)
is ON, and if it is OFF, step (10
Repeat steps 1) to (105). And ON
If so, proceed to step (106).

In step (106), the output terminal (OPI) and (OF2
) outputs a HIGH signal from the transistor (Ql
) and (Q2), magneto (
Mgl) and (Mg2) are turned on. At this time, the front curtain of the shutter is attached to a magnet (Mgl), and the rear curtain is attached to a magnet (Mgl).
They are each retained by the adsorption force of Mg2). Next, in step (107), the output terminal (OF2) and (OF
2) Output a HIGH signal from 75' to the transistor (
Turn on Q3) (Q4) and magnet (Mg3) and (
Mg4) is turned on. Then, narrowing down begins as described above. After that, in step (108), the output of the output terminal (OF2) is set to LOW, and the transistor (Q3)
Turn off. Thereby, the magnet (M g3)
is 0FFL, mirror up starts. Then, in step (109), it is determined whether the narrowing down amount has reached the desired value ΔP. This determination is made by comparing the count representing the amount of aperture inputted from the aperture pulse detection circuit with the count corresponding to ΔP. Step (109) continues until YES is determined in step (109).
09) is repeated. If the answer is YES, the process moves to step (110). In step (110), a LOW signal is output from the output terminal (OF2), and the transistor (
Q4) is turned off. Then, the magnet (Mg4)
is 0FFL, the diaphragm is locked and stopped as described above.

Next, in step (111), after step (106),
It is determined whether a predetermined time Δt has elapsed. This step is repeated until the answer is YES, and if the answer is YES, the process moves to step (112). The determination in step (111) is a step of waiting for the completion of mechanical system operations. If the shutter is moved before the mechanical system has completed its operation, it will not work properly. Therefore, by setting the time Δt for which the mechanical operation is completely completed and waiting for this time to elapse in step (111), the next operation, the shutter, can be performed after the mechanical operation is completed. This means that the vehicle will be able to run as quickly as possible. When the mechanical system operation is completed and △L has passed, the process moves to step (112), and the output terminal (OPi)
outputs a LOW signal from
FF. As a result, the magnet (M g l ) holding the shutter front curtain is turned off, and the shutter front curtain runs. Next, in step (IB), it is determined whether the time since the shutter front curtain has traveled has reached the shutter speed T, and this step is repeated until the shutter speed T has been reached. When it reaches step (114), the output terminal (
OF2) outputs a LOW signal, and the transistor (Q
2) Turn off. As a result, the magnet (Mg2) holding the shutter rear curtain moves to 0FFL, and the shutter rear curtain runs. When trailing curtain travel is completed, step (
+15) returns each part to its initial state and ends the process.

Next, to preview, switch the preview switch (
The sequence when S3) is ONL will be explained with reference to FIG.

When the preview switch (S3) is turned on, the main routine shifts to the routine shown in FIG. 9.

Then, the steps are executed sequentially starting from step (200). Steps (200) to (204) are the release routine (
Steps (100) to (104) in Figure 8)
Similarly, the aperture control amount ΔP is obtained.

Next, in step (205), the output terminal (OF2) (OF
2) outputs a HIGH signal, and the transistor (Q3
) (Q4) is turned on. Therefore, magnet (Mgl)
(Mg2) is ONL and the aperture starts running. Then, in step (206), step (1) at the time of release is performed.
In the same manner as in step 09), judge whether the narrowing amount has reached △P, and if it has not reached step (206)
is repeatedly executed, and when it is reached, the process moves to step (207). In step (207), the output of the output terminal (OF2) is set to LOW, and the transistor (Q4) is turned off, thereby setting the magnet (Mg4) to 0FFL and stopping the narrowing down. Turn on the preview switch (S3)
.

If the process continues, step (208) is repeatedly executed and this state is maintained. At this time, the mirror is not raised, so the subject light coming through the lens is directed toward the viewfinder. Therefore, you can check the image with the aperture closed through the viewfinder. Preview switch (
When S3) is turned off, the process moves to step (209), where each part is charged and returned to its initial state, and the process ends.

Note that the device of the present invention is not limited to this embodiment, and may use a U-shaped coil core (1'), for example, as shown in FIG. In this case, the attraction pieces (5') (14') are attracted by the attraction force of the magnetic flux leaking from the bent portions (A) and (B) of the coil core (1'), respectively. Since the bent part (A) and the bent part (B) are far apart, there is almost no influence of the magnetic field between them, and the attraction piece (5')
The adsorption piece (
14') will not be adsorbed. In this embodiment as well, both coils are energized when the suction piece (10') is suctioned.

Further, the present invention can be used not only for aperture control of a camera. At this time, the order of operation of the suction pieces is not limited to the order of this embodiment; for example, each part may be controlled so that the suction operation is performed after the separation operation, or The suction operation may be performed after the suction pieces are separated, and then the remaining suction pieces may be separated, thereby controlling each part.

Also, a case will be described in which the spring (13) is not used.

In this case, the aperture start lever (12) and the rotation axis (1
2B). This frictional force is generated by the narrowing start lever (1) when the suction piece (10) is attracted.
2) is set so that it can rotate when it receives force through the contact part (12A'').By doing so,
The narrowing start lever (12) is at the initial position until the coil is energized, and when energized, it rotates as the attraction pieces are attracted.

Furthermore, the control of each part by the suction pieces (5) and (14) is not limited to the case where the suction pieces are separated from each other, but other operations are limited to the suction state of the suction pieces by energizing the coil,
Control may also be performed such that the restriction is canceled in a state where separation is possible by cutting off the power supply, and other operations are permitted.

Effect of the invention The present invention provides the following effects.

Using two electromagnets, turning off one electromagnet causes the first attraction piece to separate, turning off the other electromagnet causes the second attraction piece to separate, and turning on the two electromagnets causes the second attraction piece to separate. Since each part is controlled by the suction operation of the three suction pieces, three operations can be controlled.

Furthermore, when the third attraction piece is attracted, both electromagnets are activated and the attraction force is the combined force of both electromagnets, so each attraction force is only weak.

Therefore, the number of turns of the coil can be reduced and the current can be reduced, and even though the number of electromagnets is reduced to two, the size of the device does not increase so much, and an increase in current consumption can be reduced.

[Brief explanation of drawings]

1 to 5 are structural diagrams showing the state of the device corresponding to the conducting state of the coils (3) and (4) in the device of the first embodiment of the magnetic actuator according to the present invention, and FIG. A block circuit diagram of the camera of this embodiment, FIGS. 7 and 8 are flowcharts showing the operation of the device of this embodiment, and FIG. 9 is a structural diagram of the second embodiment of the present invention. (1X2); Coil Core, (3X4); Coil, (5);
First suction piece, (14); Second suction piece, (10)
;Third suction piece, Applicant Minolta Camera Co., Ltd. Figure 3 Figure 2 Figure 2 451 5th Issue 7 Figure 8

Claims (1)

[Claims] Two coils consisting of a coil core and a coil arranged parallel to each other.
A first adsorption piece that receives only the adsorption force of one of the two electromagnets, a second adsorption piece that receives only the adsorption force of the other electromagnet, and a second adsorption piece that receives the adsorption force of both electromagnets. An electromagnetic actuator comprising: a third adsorption piece.