JPS63133132A - Position controller - Google Patents

Abstract

PURPOSE:To simplify a mechanism and to reduce the number of constituting parts and to improve the reliability of operation by driving a claw, which stops a body to be controlled in a prescribed position, by a combination solenoid. CONSTITUTION:A ratchet 85 which is rotated in accordance with the movement of a body to which a position should be controlled, a rotation extent detector which detects the extent of rotation of the ratchet 85, a combination solenoid 90 which drives a claw 91 in such directions that the claw 91 is engaged with and separated from the ratchet 85, and a combination solenoid controller are provided. When detecting it by the detection signal of the rotation extent detector that the extent of rotation of the ratchet 85 reaches a prescribed value, this combination solenoid controller drives the combination solenoid 90 to move the claw in the direction, where the claw is engaged with the ratchet 85, and positions the body to be controlled. Thus, the mechanism is relatively simple and the number of constituting parts is small and the reliability of operation is high because a mechanism which preliminarily nets the body to be controlled is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a position control device that positions a controlled object at a predetermined position, and is applicable, for example, as an aperture control device for a camera. .

(Prior Art) A position control device that positions a controlled object at a predetermined position is used as an aperture control device of a camera and other devices.

Is the conventional position control device covered? li! The I body is set in advance by mechanically moving it against the biasing force, and is held at this center position by an electromagnet, etc., and then the amount of movement is detected while moving in the biasing direction, and the predetermined position is set. When a value detection signal is obtained, the pawl is driven to lock the controlled object. Therefore, a centering mechanism for the controlled object is required, and the mechanism is complicated and requires many parts, and its operation is not reliable.

(Objective) An object of the present invention is to provide a position control device that has a relatively simple mechanism, fewer components, and highly reliable operation by eliminating a mechanism for setting a controlled object in advance. .

(Structure) The present invention includes a windmill that rotates as a controlled object whose position is to be controlled moves, a rotation amount detection device that detects the amount of rotation when the windmill starts rotating, and a claw. Then, the amount of rotation of the windmill is adjusted to a predetermined amount of rotation by a combination solenoid that drives the pawl in a direction to engage the windmill and in a direction to separate the pawl from the windmill, and a detection signal from the rotation amount detection device. The present invention is characterized in that it has a combination solenoid control device that determines the position of the controlled object by driving the combination solenoid in such a way that its pawl engages with the wind turbine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a position control device according to the present invention is applied to a camera will be described below with reference to the drawings.

FIG. 1 shows an overall overview of an embodiment of the device of the invention. 1st
In the figure, a microprocessor unit (rMP
(referred to as UJ) 11 is an analog-to-digital converter 16;
Based on the input signals from the timing switch 18 and the position sensor 19, the motor 14 and the combination solenoid 21 are controlled through the morph drive circuit 12 and the combination solenoid drive circuit 20. The motor 14 drives the aperture, shutter, and mirror of the camera, as will be explained in detail later, and its back electromotive voltage Vm is applied to the MPU 1l through the multiplexer 15 and the analog-to-digital converter 16. The voltage of a timing adjustment resistor 17 is also applied to the MPU II through a multiplexer 15 and an analog-to-digital converter 16. The timing switch 18, position sensor 19, and combination solenoid 21 will be explained later. Reference numeral 13 is a power source for driving the motor 14.

FIG. 5 shows a block diagram of the mechanism driven by the motor 14. In FIG. 5, the rotational force of the motor 14 is decelerated by a speed reduction device 24 and then transmitted to a mirror cam 25, an aperture cam 36, and a shutter cam 38, and the aperture cam 36 drives an aperture lever 46 on the camera side.

The aperture lever 46 is a controlled object whose position is to be controlled to a predetermined position, and the movement of the aperture lever 46 is accelerated by a speed increasing mechanism 30, and when the speed increasing mechanism 30 reaches a predetermined position, a stop mechanism is activated. 31 detects this and stops it, and controls the aperture lever 46 to a predetermined position.

The aperture lever 46 is linked to a lens-side aperture lever 57, and controls the lens-side aperture lever 57 to a predetermined position.

FIG. 8 shows the aperture cam 36, shutter cam 38, aperture lever 46, and the surrounding mechanisms. In Figure 8,
The gear 33 is rotationally driven by the motor 14, and the gear 33 rotationally drives the cam gear 34. The cam gear 34 is integrally provided with an aperture cam 36 and a shutter cam 38. A lever 40 is provided on the side of the aperture cam 36 so as to be rotatable about a shaft 41. Lever 40 has a cam follower 42. One end of a connecting lever 44 is pivotally attached to the lever 40, and a pin 48 of an aperture lever 46 is fitted into a long hole 45 formed at the other end of the connecting lever 44.

The aperture lever 46 is shaped like a hell crank and rotates about a shaft 47 in a plane parallel to the rotation plane of the lever 40 . The aperture lever 46 and the lever 40 are biased toward each other by an aperture biasing spring 53. A tip 49 of the aperture lever 46 is in contact with an aperture lever 57 on the lens side. The aperture lever 57 is the aperture lever 46 on the camera side.
is urged to move following the The rotation of the aperture lever 46 in the clockwise direction in FIG. 8 is restricted by the bending portion 50 of the aperture lever 46 coming into contact with the stopper 55, and the rotation of the aperture lever 46 in the clockwise direction in FIG. rotation is restricted. Another bent portion 51 is formed on the aperture lever 46, and a roller 58 is in contact with this bent portion 51.

FIG. 6 shows the construction of a speed increasing mechanism and a stop mechanism that are linked to the aperture lever 46 through the roller 58.

In FIG. 6, the roller 58 is provided on a lever 77 that rotates about a shaft 78 and whose one end edge constitutes a fan-shaped gear 79. As shown in FIG. The rotational force of the sector gear 79 is transmitted to the wind turbine 85 via the speed increasing gear train 80, 81, 82, 83,
The ratchet wheel 85 is rotated at high speed. An encoder disk 86 having a large number of slits 87 at regular intervals in the circumferential direction is integrally attached to the windmill 85.

Photo ink pens 88 are installed so as to sandwich both sides of the encoder disk 86. The photo ink converter 88 detects the light transmitted through the slit 87 of the encoder disk 86 and outputs a signal, and corresponds to the position sensor 19 in FIG. 1.

By counting this output signal, the rotation amount of the ratchet wheel 85,
Furthermore, the amount of rotation of the aperture lever 46 can be detected. That is, the encoder disk 86 and the photo ink club 88 constitute a rotation amount detection device.

In FIGS. 6 and 7, a claw 91 faces the outer periphery of the ratchet wheel 85. As shown in FIGS. Claw 91 is combination solenoid 9
When the combination solenoid 90 is excited in the forward direction and in the opposite direction, the pawl 91 is driven by the ratchet wheel 8.
5, and the pawl 91 engages with the pawl wheel 8.
It is driven in the direction away from 5. The combination solenoid 90 connects the MPU II and the drive circuit 20 (first
When the rotation amount of the ratchet wheel 85 reaches a predetermined rotation amount according to the detection signal from the rotation amount detection device, the combination solenoid 90 is driven by a combination solenoid control device (see figure). The pawl 91 is driven to move in the direction of engagement with the ratchet wheel 85 to determine the position of the aperture lever 46 as a non-controlled body. The specific configuration of the combination solenoid 90 will be described later.

In FIG. 8, a cam follower 62 provided on a chassis holder 60 is in contact with the shack cam 38. The shutter charge lever 60 is rotatable around a shaft 61, and when it rotates clockwise in FIG. Soto.

In FIG. 8, a gear 66 is meshed with the cam gear 34. A base of a brush 67 is fixed to the gear 66. The brush 67 is in sliding contact with the conductive pattern shown in FIG. 9, and the timing switch 18 shown in FIG.
It consists of The conductive pattern shown in FIG. 9 is composed of three conductive bags 68, 69, and 70, and these conductive patterns are arranged in the above order from the outer circumferential side to the inner circumferential side. The conductive pattern 68 constitutes the first switch SWI, and the conductive pattern 69 constitutes the second switch SW2. Conductive pattern 70 forms a common contact of conductive patterns 68 and 69. The brush 67 can radially straddle the three conductive patterns 69, 70, and switches SWI and SW2 are turned on and off depending on its rotational position. Switches SWI and SW2 constitute the timing switch 18 in FIG.

The brush 67 shown by the chain line in FIG. 9 is in the home position 71, and the switches SWI and SW2 are both on. When the brush 67 rotates clockwise in FIG. 9, switches SWI and S(, 12 are both turned off, and when the aperture count start position 72 is reached, switch series 1 is turned on. When the brush 67 rotates further, switch SWI and S(, 12 are turned off. is turned off, and when it reaches the stop-down end position 73, the switch SW2 is turned on. When the brush 67 rotates further, the switch SW2 is turned off, and when it reaches the mirror-up start position and the re-metering start position 74, the switch SW2 is turned on.
I turns on. When the brush 67 rotates further, the switch SWI is turned off, and the brush 67 rotates approximately 180 degrees from the Baum position 71 to the mirror-up end position 7.
When the value reaches 5, the switch SW2 is turned on. Just before the brush 67 further rotates clockwise and reaches the home position 71, the switches SWI and SW2 are both turned off, and then the home position 71 is reached.

FIGS. 10 and 11 show specific examples of a combination solenoid, in which a bistable combination solenoid is used. A movable core 94 is provided inside the coil 93 so as to be rotatable about a shaft 97, and the claws 91 are formed integrally with the movable core 94. The coil 93 forms an S pole and an N pole at the bottom, and has a pair of suction plates 95.
At 95, the movable iron core 94 is attracted. Outside the coil 93 are a pair of magnets 96,96.

Magneso 1-96.96 has S in the thickness direction, that is, in the inside and outside direction.
A pole and a north pole are formed.

Now, when the coil 93 is energized to form S and N poles on the top and bottom of the coil 93, one magnet 96 and the coil 93
A portion 99 of high magnetic flux density is generated between the other magnet 96 and the coil 93, and a portion 100 of low magnetic flux density is generated between the other magnet 96 and the coil 93, and the movable iron core 94 has a magnetic flux as shown in FIG. Rotate toward higher density. coil 93
If the direction of energization is reversed, the portions with high and low magnetic flux density will be reversed, and the movable iron core 94 will rotate in the opposite direction.

When the coil 93 is de-energized, the movable core 94 maintains its current rotational position.

FIG. 12 shows an example of a drive circuit for a bistable combination solenoid, in which the coil 93 can be bidirectionally energized by drive elements such as transistors connected in a cross-section manner. Each transistor is controlled by a solenoid control device such as the MPU 11 shown in FIG.

Next, the operation of the above embodiment will be explained with reference to FIGS. 13 to 15.

When the operation starts, the combination solenoid 90 is first energized and the claw 91 is placed in a standby position away from the windmill 85. When released in that state, the motor 14
starts rotating in the forward direction, the aperture cam 36 is rotationally driven, the aperture lever 46 rotates, and the aperture lever 57 on the lens side rotates.
starts moving (see Figure 13C). The brush 67 is driven as the motor 14 rotates, and when it reaches the aperture count start position 72, the switch SWI is turned on and the aperture count is started. The aperture count is performed by counting the detection pulses of the photo ink club 88, and when a predetermined aperture count value is reached, the solenoid 90 is energized in the opposite direction to engage the pawl 91 with the windmill 85, causing the windmill 85 to rotate. By stopping the aperture lever 46, the movement of the aperture lever 46 is stopped. The predetermined aperture count value is calculated based on the photometric value.

Here, the encoder disk 86 is rotationally driven via a speed-increasing gear train, and due to mechanical rattling etc.
As indicated by the symbol t in FIG.
Since the detection pulse is output from 8, the timing of starting counting of the detection pulse is shifted accordingly. The timing adjustment resistor 17 in FIG. 1 is for adjusting such count start timing.

Next, determine whether the mode is release mode or program preview mode, and if it is release mode, the aperture end position 7
3 and switch SW2 is turned on (13th
(See figure) Turn on both the front curtain set magnet and the rear curtain set magnet of the shutter. A shutter having such a leading curtain set magnet and a trailing curtain set magnet is well known. It takes about 30 m5 from the start of the aperture count to the turning on of switch 2. When the motor 14 further rotates and reaches the mirror-up start position 74, the switch SWI is turned on, thereby performing light measurement again and starting the mirror-up operation (see Figure 13C), and the mechanical charge of the shutter is released. is started. At this time, the front curtain and rear curtain of the shutter are held by respective set magnets.

The motor 14 rotates further to reach the mirror amplifier end position 75.
When the switch SW2 is turned on, the motor 14 is stopped, the mirror amplifier operation is completed, and the mechanical charge release of the shutter is completed (see FIG. 13C).
.

The release then turns off the leading curtain set magnet of the shank, and the leading curtain begins to move.

At the same time, time is measured, and when the shutter opening/closing time calculated in advance based on the photometric value is reached, the rear curtain set magnet of the shutter is turned off and movement of the rear curtain is started. After that, the solenoid 90 is energized in the positive direction to set it to the standby position,
Furthermore, the motor 14 is driven to rotate in the forward direction. The rotation of the motor 14 starts the return operation of the mirror, and the rotation of the shutter cam 38 rotates the shutter set lever 60 to start mechanical charging of the shutter.
Furthermore, the rotation of the aperture cam 36 causes the aperture lever 46 to rotate, and centration of the aperture lever is started. During this time, film feeding is started.

When the motor 14 reaches the home position 71 in this manner, the motor 14 is stopped and film feeding is completed to prepare for the next release (see FIG. 13C).

The operation when the program preview mode is selected after the aperture lever stops moving will be described with reference to FIG. 14. In the program preview mode, when the switch SW2 is turned on after the aperture lever stops moving, the motor 14 is stopped.

Therefore, the shutter does not operate while the aperture is stopped down to a predetermined aperture value, and mirror amplification is not performed, so that it is possible to observe the depth of field, etc. at the predetermined aperture value. When the program preview is canceled, the solenoid 90 is energized in the forward direction to be in the standby position, and the motor 14 starts rotating in the reverse direction.

As a result, the seven strokes of the aperture lever in the opposite direction start, and when the aperture count start position 72 is reached and the switch SWI is turned on, the reverse rotation of the aperture lever 1- is completed, and the motor 1
4 stops rotating and returns to the home position 71.

From the start of the motor's rotation in the normal rotation direction shown in FIG. 14 to the end of the mirror up and the end of the release of the mechanical charge of the shutter, there are motor 14
Higher accuracy can be obtained by rotating at a constant speed. Therefore, in the first embodiment described above, a constant speed control device for the motor as described below is incorporated.

In FIG. 1, the motor drive circuit 12 is an MPU], 1
When the motor 14 is on, the terminal voltage Vm of the motor 14 is equal to the power supply voltage vb, and when the motor 14 is off, the voltage Vm is equal to the voltage Vb. C = KN.

Here, Ve is the back electromotive force of the motor 14, K is the proportionality constant,
N is the number of rotations. The MPU II samples the terminal voltage Vm (-Ve) when the motor is off through the analog-to-digital converter 16, and controls the duty of the command signal to the motor drive circuit 12 so that the value of the back electromotive force Ve is constant. .

3 and 4 show the operation of the constant speed control device, FIG. 3 shows the case where the power supply voltage vb is low, and FIG. 4 shows the case where the power supply voltage vb is high. G It will be done.

Further, in order to perform highly accurate control, it is desirable that the start-up of the rotation of the motor 14 is constant.

However, due to variations in the power supply voltage, the start-up of the motor's rotation also varies. Therefore, as shown in Fig. 2, the relationship between the ratio of the back electromotive voltage Ve of the motor to the target value Veo and the duty of the motor drive command signal from the MPU II is determined in advance by adjusting the duty as the time elapses after the motor is turned on. It is stored in the MPU II as a table, and the on time of the motor 14 is determined according to this table. In FIG. 2, arrows indicate the passage of time after the motor is turned on.

By doing so, when Ve/νeo is relatively large at a certain point in time, the motor-on duty is controlled to be low, and as a result, the rise in rotation of the motor is controlled so as to follow a constant rise curve.

In order to detect the amount of rotation of the ratchet wheel 85 for determining the position of the aperture lever 46 as a controlled object, a circuit as shown in FIG. 16 and a pallet wheel as shown in FIG. 17 are used. A mechanism may also be used. In FIG. 17, the goose wheel 102 replaces the ratchet wheel 85 in FIG.
The ends of both arms of an ankle 103 alternately abut on this flywheel 102, and the flywheel 102 rotates intermittently at regular intervals. The pallet wheel 103 replaces the ratchet wheel 91 of the combination solenoid 90 in FIG.
A back electromotive force is generated in the solenoid 90 every time the solenoid 03 rotates back and forth. Therefore, as shown in FIG. 16, if the back electromotive force of the solenoid 90 is detected by the back electromotive pulse detection circuit 107, and this detection signal is input to the MPU II and counted, the amount of rotation of the goose wheel 102 can be determined. You can see the location of 46. When it is determined from the count value that the aperture lever 46 has reached a predetermined position, the solenoid 90 is energized to stop the rotation of the goose wheel 102. In the example shown in FIG. 2, the solenoid 90 is connected to the l-transistor 1 by the constant current source 105.
Driven through 06.

(Effects of the Invention) According to the present invention, the pawl that stops the controlled object at a predetermined position is driven by a combination solenoid, so that when the controlled object is returned to its original position, the pawl is in the excitation state of the combination magnet. All you have to do is switch and move it away from the ratchet wheel, and no special setting mechanism is required. Therefore, the mechanism is simple and the number of component parts is small.
A position control device with highly reliable operation can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an overview of an embodiment of a position control device according to the present invention, FIG. 2 is a diagram showing an example of a duty table of a constant speed control device portion in the same embodiment, and FIG. 4 is a timing chart showing an example of the operation of the constant speed control device; FIG. 4 is a timing chart showing another example of the operation of the constant speed control device; FIG. 5 is a block diagram showing an overview of the mechanical parts in the above embodiment; Figure 6 is a perspective view of the speed increasing mechanism and stop mechanism in the above embodiment, Figure 7 is a front view of the stop mechanism in the above, and Figure 8 is a front view of the aperture mechanism and shutter setting mechanism in the above embodiment. 9 is a front view of the timing switch part in the above embodiment, FIG. 10 is a sectional view showing an example of the combination solenoid used in the above embodiment, FIG. 11 is a diagram of the operating principle of the combination solenoid, and FIG. FIG. 12 is a circuit diagram showing an example of a drive circuit for the combination solenoid, FIG. 13 is a timing chart showing the operation of the above embodiment, FIG. 14 is a flow chart showing the operation of the above embodiment, and FIG.
4, a flowchart showing the operation of the above embodiment,
FIG. 16 is a circuit diagram showing another example of a ratchet wheel rotation amount detection device, and FIG. 17 is a front view showing a mechanical part of the same rotation amount detection device. 11...MPU as a combination solenoid control device, 46...Aperture lever as a controlled object, 8
5.. Ratchet wheel, 86.. Encoder that constitutes the rotation amount detection device, 88.. Photo ink rubber that constitutes the rotation amount detection device, 90.. Combination solenoid.
91... Nails. v;, il country

Claims (1)

[Claims] It has a ratchet wheel that rotates as the controlled object whose position is to be controlled moves, a rotation amount detection device that detects the amount of rotation when the ratchet wheel starts rotating, and a pawl. The amount of rotation of the ratchet wheel reaches a predetermined amount of rotation by a combination solenoid that drives the pawl in a direction to engage the ratchet wheel and in a direction to separate the pawl from the ratchet wheel, and a detection signal from the rotation amount detection device. and a combination solenoid control device that determines the position of a controlled object by driving the combination solenoid in a direction in which its pawl engages with a ratchet wheel.