JPH0432656Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sector opening/closing device using a step motor in a camera shutter.

[Prior Art] Conventionally, in shutter devices that open and close sectors using a step motor that rotates forward and backward in synchronization with a pulse signal, the opening amount of the sector is determined by the amount of rotation of this step motor. In this device, in order to perform accurate exposure operation, it is necessary to maintain a constant magnetic pole relationship between the rotor and stator of the step motor before and after shutter operation.

However, before operation, the step motor is not energized and is kept in a stopped state only by the magnetic coupling force between the stator and rotor inside the motor, so if any large external force or impact is applied to the camera, the rotor may The magnetic poles of the stator and rotor may become out of phase due to rotation. If the shutter is operated with the stator and rotor out of phase, the step motor will not synchronize with the drive signal, and not only will the correct exposure operation not be performed, but the step motor will stop with the sector open. Sometimes.

Furthermore, if for some reason a sudden problem occurs in the drive signal or the operation of the sector opening/closing member during shutter operation, the shutter may stop with the sector open or the shutter may stop with the magnetic pole phase of the stator and rotor out of alignment. Therefore, a step motor-driven shutter is equipped with a switch that is linked to the sector opening/closing operation in order to detect the stop state before and after operation.The state of this switch is checked before and after the shutter is operated, and in the event of an abnormality, a correction signal is sent to the step motor. is output or an abnormality is displayed.

On the other hand, in general, in a switchgear, the play caused by the clearance and backlash of the gear mechanism that transmits the rotation of the step motor to the sector is always moved in one direction, so that the sector follows the rotation of the motor as accurately as possible. Therefore, a spring is provided that biases the sector in the closing direction.

[Problem to be solved] However, the above-mentioned spring and the switch linked to the sector opening/closing operation both increase the load on the motor output, so conventional ones require a high-output motor and the motor size increases. It has the problem of In addition, the switch must occupy a small space as part of the sector opening/closing device, and must be configured to operate at a predetermined timing in response to the sector opening/closing operation, and until now there has been no switch with a configuration suitable for such a switch. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sector opening/closing device in which a step motor can be started under a light load condition.

[Means for Solving the Problems] A feature of the present invention is that a switch is composed of a spring member and a fixed contact piece, and this switch biases the sector in a direction to close it, and when the sector is in the closed position, the switch The sector drive member is closed with a predetermined gap, and the control circuit detects the release signal of the switch at the position where the sector is to be closed and rotates the step motor in the sector closing direction. It's in the point where you let it happen.

[Function] Therefore, in the present invention, in the initial state before the shutter operates, the biasing force of the spring is regulated by the fixed contact piece and there is a gap between it and the pin of the sector drive wheel 7.
No spring biasing force acts on the step motor via the power transmission means. Therefore, the step motor can be started with a light load, and the torque required to draw the step motor into synchronous rotation, that is, the pool-in torque, is small.

[Examples] Examples of the present invention will be described below with reference to the drawings.

First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

As is well known, the configuration of the step motor M includes a rotor made of a rotatably supported permanent magnet magnetized with multiple radial poles, and a plurality of magnetic pole parts that are related to the rotor and are opposed to the outer periphery of the rotor. It consists of at least two stators, and a coil wound around the stators to excite the stators.

1 and 2, a pinion 2 is fixed to the tip of an output shaft 1 of a step motor M for transmitting the rotational force of this motor. A base plate 4 is attached to the lower surface side of the base plate 3 that holds the lens with screws as shown in FIG. A sector chamber R for storing the sector 5 is formed between the two.

The sector drive lever 6 is rotatably supported by a rotating shaft 3a provided on the base plate 3, and is supported by the lower surface of the step motor M so as not to slip out upward.

A sector drive wheel 7 is rotatably attached to the sector drive lever 6, and an adjustment pin 8 fixed to the sector drive wheel 7 engages with a groove 6b formed in the sector drive lever. Both 6,7
rotation is regulated. Furthermore, a sector pin 6a is integrally formed on the sector drive lever 6, and this sector pin passes through the base plate 3 and engages with a groove portion of the sector 5. Further, the sectors 5, 5 are two pieces rotatably supported by pins 3b, 3b provided on the base plate 3, respectively, and arranged in symmetrical positions, and are configured to determine the opening 0.

The sector drive wheel 7 attached to the sector drive lever 6 includes a gear 7a, a degree determining part 7b, and a pin 7.
c is integrally formed, and this gear meshes with the idler wheel 9, and this determining part is for regulating rotation in relation to a pin 3c provided on the main plate 3, and this pin is a spring 10.

The adjusting pin 8 fixed to the sector drive wheel 7 has a diameter portion that engages with the sector drive wheel and a diameter portion that engages with the groove portion 6b of the sector drive lever 6 that are eccentric. A predetermined friction slip torque is rotatably fixed at 7 by caulking or the like. Therefore, by turning the groove part of the adjustment pin 8 with a screwdriver etc., the tooth part 7 of the sector drive wheel 7 can be adjusted.
The phase relationship between a and the sector pin 6a of the sector drive lever 6 can be adjusted.

The spring 10 constitutes the fixed contact 13 and the switch SW. That is, the spring 10 is made of a conductive material and is formed in the shape of a torsion coil spring as shown in the first figure, and the center portion is supported by a pin 3f provided on the main plate 3 and can be engaged with a pin 7c of the sector drive wheel 7. One end is in elastic contact with a fixed contact 13 fixed to be conductive to the pattern 12a of the printed wiring board 12 to constitute a switch SW, and the other end is soldered to the pattern 12b of the printed wiring board to be conductive. Fixed by

Further, as shown in FIG. 1, when the sector 5 is in the closed state before and after the shutter is operated, the spring is moved so that a predetermined gap is provided between one end of the spring 10 and the pin 7c of the sector drive wheel 7. are arranged in such a relationship that the biasing force of is regulated by the fixed contact 13,
This fixed contact and the spring 10 are electrically connected, that is, the switch is closed.

In this way, in the initial state before the shutter operates, the biasing force of the spring 10 is restricted by the fixed contact piece 13 and there is a gap between it and the pin 7c of the sector drive wheel 7.
No spring biasing force acts on the step motor M via the gear trains 9 and 2. Therefore, step motor M
can be started under light load conditions, and the torque needed to draw the step motor into synchronous rotation, that is, the pool-in torque, is small, so it is effective for speeding up the opening and closing of sectors 5, 5, and making the step motor more compact. . Spring 1 is also applied to step motor M.
Since no biasing force of 0 is applied, the step motor does not rotate under the load of the spring 10 even when an impact is applied, and when it rotates slightly, the spring acts as a load and rotates. There is no.

Further, one end of the spring 10 separates from the fixed contact 13 immediately after the shutter is operated, and engages with the pin 7c of the sector drive wheel 7 to urge the sector drive wheel 7 counterclockwise and in the direction of closing the sector 5. . This biasing force always eliminates backlash such as the clearance of the rotation support part from the pinion 2 of the step motor to the sector drive lever 6 and the backlash of the meshing part.
direction so that the sector drive lever 6 accurately follows the operation of the step motor M. Incidentally, the biasing force of the spring 10 is the same as that of the step motor M.
The output torque is set appropriately below the output torque of , and in consideration of the above-mentioned force for reducing backlash and the contact pressure with the fixed contact 13. The idler wheel 9 is rotatably supported by a rotating shaft 3d provided on the base plate 3, and is supported by the lower surface of the step motor M so as not to slip out upwardly as shown in FIG. 2a, and further includes a pinion 9a and a gear 9b. It is formed integrally with
This pinion meshes with the tooth portion 7a of the sector drive wheel 7, and this gear meshes with the pinion 2. Further, a pillar 3e for mounting a step motor M is integrally formed on the base plate 3, and the step motor M is fixed to this pillar 3e with a set screw 11, and the pinion 2 and idler wheel 9 engage to transmit rotation. is now possible.

On the other hand, the control circuit 14 controls two coils L1 and L2 (FIG. 3a) in a step motor M which is composed of two sets of stator and coil.
, an indicator lamp 15 that indicates abnormality in shutter operation, patterns 12a and 12b to which the spring 10 and fixed contact 13 are connected, and a circuit that outputs photometric information, distance information, etc. of the subject are connected. The control circuit 14 causes current to flow through the coils L1 and L2 at all times and alternately reverses the direction of the current to the positive (+) or negative (-) direction, as shown in FIG. 3a. A drive signal of a known two-phase excitation bipolar drive system is output. This drive signal corresponds to the photometric information of the subject, etc., and for example, if the subject is dark, the number of excitation pulses for the coil is increased, and if the subject is bright, the number of excitation pulses is determined as appropriate. It is something. FIG. 3b shows the operation of the switch SW consisting of the spring 10 and the fixed contact 13 when activated by the drive signal shown in FIG. 3a, and FIG. 3c shows the operation of the sector 5 at that time. It is a thing.

Furthermore, FIG. 4 shows a flowchart for preventing sector release and operating the step motor M normally, and the operation of the flowchart is performed at least either before or after the shutter is operated. The switch SW has a spring 10 and a fixed contact 13
Since the shutter is composed of
0 and 13 are in contact and are in the ON state.

However, if some kind of large external force or shock is applied to the camera, or if an abnormality occurs in the opening/closing operation of the sector 5, the stopping positions of the rotor in the step motor M, the sector drive wheel 7, etc. will be distorted, and the spring 10 and the fixed contact 13 becomes non-contact, and the switch SW becomes OFF.

Then, the switch SW is checked, and if it is ON, this routine ends, but if the switch SW is OFF, a drive signal is sent to the step motor M for a predetermined number of pulses in the direction to close sector 5. The second drive signal is output to operate the step motor M, and then the number of times this routine has passed is checked, and if it is less than the predetermined number of times, the process returns to the step of checking the switch SW and checks whether the switch SW is ON or OFF. If checked, this routine ends if it is ON, and if it is OFF, the drive signal output is repeated again.

Checking the number of times the routine has passed is used to escape from this routine if the sector opening/closing mechanism fails and stops working at all.If the switch SW does not turn on even after repeating the specified number of times, an abnormality display signal is output. An indicator lamp 15 indicates an abnormality.

Next, the operation of the present invention will be explained.

First, FIG. 1 shows the state before operation of the camera, in which the sector drive wheel 7 is rotated in its counterclockwise direction setting part 7b.
and the pin 3c are engaged, and the two sectors 5, 5 that are engaged with the sector pin 6a are also at the lens aperture 0.
is closed, and the coil of the step motor M is also not energized.

In this state, the power of the control circuit 14 is turned on by the release means of the camera, the switch SW is checked as shown in Fig. 4, and under normal conditions, the photometering means etc. are also operated, and the step motor M is turned on based on the information of the subject. A drive signal for the sector is determined, for example, as shown in FIG. 3a, and this output signal is sequentially conducted to two coils L1 and L2, thereby opening and closing the sector as described below.

In Fig. 3, the output signals from the 1st pulse to the 4th pulse cause the coil L of the step motor M to
1, an excitation current that alternately reverses flows through L2,
The pinion 2 of the step motor M rotates clockwise in steps. The rotation of the pinion 2 is transmitted to the sectors 5, 5 via the idler wheel 9, the sector drive wheel 7, and the sector drive lever 6, and this sector is opened and the spring 10 and the sector drive are activated from the first pulse to the second pulse. The pin 7c of the car engages, the spring 10 and the fixed contact 13 are separated, and the switch is turned on.
SW turns OFF and exposure starts from the 3rd pulse.

Thereafter, up to the 4th pulse, the sector 5 is opened, and the step motor M starts to rotate in reverse at the 5th pulse drive signal, and the pinion 2 is opened until the 8th pulse.
rotates counterclockwise to close sector 5.

Just before the end of the operation, the spring 10 and the fixed contact 13 come into contact again, and the spring 10 and the pin 7 of the sector drive wheel 7 contact each other again.
c is released, the switch SW is turned on, and the sector drive wheel's adjustment part 7b and the pin 3c of the main plate are operated to the related position, and the opening/closing operation of the sectors 5, 5 is completed.

After that, the switch SW is checked as shown in Figure 4 to ensure that sectors 5 and 5 are closed, and the camera operation ends. However, if the step motor or opening/closing mechanism fails, sector 5 may be completely closed. If it does not close, the indicator lamp 15 lights up to notify you of the abnormality.

On the other hand, by rotating the adjustment pin 8 that connects the sector drive wheel 7 and the sector drive lever 6, the phase relationship of the sector drive lever 6 changes, and the amount of overlap between the two sectors 5 before operation and during opening/closing operation is changed. Since the aperture diameter of the lens changes, it is used to adjust the exposure amount.

In the above operation explanation, the step motor M is reversed from the 4th pulse to the 5th pulse.
The timing of this inversion pulse depends on information such as photometry and distance. When the subject is bright or when using a strobe to take close-up shots, the inversion is performed at a position with a small number of pulses, and when the subject is dark or when using a strobe to take a long-distance shot. In the case of imaging, it is programmed to reverse at the position where the number of pulses is large.

In addition, in the above embodiment, the switch SW is turned off from the first pulse to the second pulse, but this operation timing is within the range where the sector 5 is not opened.
Moreover, it is set appropriately depending on the number of poles of the rotor and stator in the step motor M, and the step motor performs a predetermined rotation under a light load without being subjected to the biasing force of a spring, which improves starting performance. It is.

Next, FIGS. 5 and 6 show a second embodiment in which the fixed contact of the switch SW is configured to be adjustable compared to the structure of the first embodiment.

Sector drive vehicle 10 interlocked with step motor M
7 and a spring 110 which biases the play of the transmission mechanism in one direction and forms one end of the switch are constructed in the same manner as in the first embodiment. The contact plate 113, which constitutes the switch together with the spring 110, is connected to the contact portion 11 that contacts the spring.
3a and a pattern 112a connected to the control circuit.
The contact plate 113 and the pattern 112a are electrically connected to each other by being fixed onto the printed wiring board 112 with mounting screws 120. This contact plate 113 is connected to the sector drive vehicle 10
This is to adjust the timing at which the switch SW changes from ON to OFF when contact with the spring 110 is cut off by the operation of 7.During the assembly process, the switch SW is switched off within the range where the sector is closed as shown in Figure 3.
Adjustments are made by rotating the contact plate 113 to turn the SW from ON to OFF. Therefore, it is possible to easily and accurately match the operation timing of the switch SW with the movement of the step motor and the sector opening/closing member.

In addition, in the first embodiment, the sector drive member 6,
Although 7 is configured in a lever type, it can be similarly configured in a ring type, which is well known as a sector drive member. Further, in the first embodiment, the step motor M and the sector drive members 6, 7 are connected to the gear mechanisms 2, 9.
Although it has a configuration in which it is connected by a chisel, it has not only a gear mechanism but also two levers, one lever has one pin and the other lever has a groove that fits the diameter of the pin. The same effect can be obtained even if a part of the transmission means is configured to transmit information using a pin and the groove.

Further, in the above embodiment, the sector drive wheel 7 is provided with a spring 10.
However, the same effect can be obtained even if it is related to the sector drive lever 6.

[Effect] As explained above, in the present invention, in the initial state before the shutter operates, the biasing force of the spring is restricted by the fixed contact piece and there is a gap between the pin of the sector drive wheel 7 and the power transmission means. No spring biasing force acts on the step motor through the spring. Therefore, the step motor can be started with a light load, and the torque required to draw the step motor into synchronous rotation (in other words, the pool-in torque) is small, allowing for faster opening and closing of sectors, miniaturization of the step motor, and consumption of the step motor. This is effective for power saving, etc. Further, since the biasing force of the spring does not act on the step motor, the step motor does not rotate even if an impact is applied.

[Brief explanation of the drawing]

Figures 1 to 4 show the first embodiment; Figure 1 is a plan view, Figure 2 is a sectional view, and Figure 3 is a diagram of motor drive signals from the control circuit and operation diagrams of switches and sectors. , FIG. 4 is a flowchart of the check process of the switch in the control circuit, and FIGS.
This shows an example, and Fig. 5 is a partial plan view, and Fig. 6 is a partial plan view.
The figure is a sectional view of FIG. 5. 1... Rotor, 5, 5... Sector, 6, 7, 1
07...Sector drive member, (6...Sector drive lever, 7,107...Sector drive vehicle), 7a...
Sector drive car pin, 10, 110... Spring, 1
2,112...Printed wiring board, SW, 10,1
3... Switch (10... Spring, 13... Fixed contact), 14... Control circuit, 0... Lens aperture, M
...Step motor.

Claims (1)

[Claims for Utility Model Registration] Consisting of a sector, a sector driving member, a step motor, a switch, and a control circuit, the sector is for opening and closing a lens aperture, and the sector driving member is for opening and closing a lens aperture. The step motor reciprocates to drive the sector drive member, and the step motor includes a rotor which is magnetized with a plurality of magnetic poles in the radial direction and can rotate forward and reverse to operate the sector drive member, and a rotor that faces the outer periphery of the rotor. comprising a plurality of stators having a plurality of magnetic pole parts and arranged to stop the rotor by the magnetizing force at a stop position corresponding to the closed position of the sector; and a coil wound around the stator; The switch includes a spring member and a fixed contact piece, and the switch biases the sector in a direction to close it and closes the sector with a predetermined gap from the sector drive member in the closed position of the sector. The step motor drive is characterized in that the control circuit detects an open signal of the switch at a position where the sector is to be closed and rotates the step motor in the sector closing direction. Sector opening/closing device.