JPH0447698Y2 - - 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] As a first example of the prior art, a shutter is known that uses a step motor that rotates in steps in synchronization with a pulse signal, and determines the opening amount of a sector by the amount of rotation of this step motor.

As a second example, a shutter in which the rotational speed of a step motor is determined by built-in data is also known.

Furthermore, as a third example, the shutter blades connected to the rotor open and close due to the rocking of the rotor biased by a spring, and a stepper is provided that can adjust the stopping position of the rotor before the shutter operates. There is one (Japanese Unexamined Patent Publication No. 111844/1983).

[Problem to be Solved] Incidentally, in the first example, it is necessary for the shutter to accurately match the phase relationship between the step motor and the sector. A gear mechanism is generally used as a means for transmitting the rotation of the step motor to the sector, and in order for this gear mechanism to transmit rotation smoothly, a backlash is provided in the meshing portion and a clearance is provided in the rotation support portion. In addition, each component necessarily has manufacturing errors, and also has errors in the step angle due to the coupling force and positional accuracy of the magnetic poles of the stator and rotor of the step motor.

Therefore, backlash, clearance, component errors, step angle errors, etc. result in phase errors between the step motor and the sector, and this phase error makes it difficult to obtain an accurate sector opening amount, especially when shooting when the subject of the camera is bright. This becomes a serious problem if the sector opening amount is small.

In addition, in a shutter in which the rotational speed of the step motor is determined by the built-in data of the second example, by adjusting the phase between the step motor and the sector, it is possible to adjust the rotation speed of the step motor over time. The method of changing the slope of the line showing the relationship between aperture changes also changes the relationship between the light emission timing based on distance information during strobe photography and the aperture diameter when the strobe device fires at that timing. Therefore, it is undesirable.

Furthermore, in the third example, since the stop position of the rotor is changed by adjusting the stopper, the relative position between the permanent magnet and the coil changes, and the starting characteristics when the rotor coil is energized change. It depends on how the stopper is adjusted. That is,
Since the operating characteristics and responsiveness of a step motor are greatly influenced by the size of the air gap between the rotor and the stator, naturally the planar position of the magnetic poles also affects the starting characteristics.

Therefore, the purpose of the present invention is to configure a phase adjustment member without changing the initial stop position of the rotor by adjustment, so that phase adjustment can be achieved without changing the operating characteristics of the sector, and the step motor can be adjusted. Exposure amount resulting from sector phase error,
Another object of the present invention is to provide a sector opening/closing device that can easily adjust aperture diameter (aperture diameter) errors during strobe photography.

[Means for Solving the Problems] A feature of the present invention is that a sector drive member is composed of an input member and an output member, and the input member receives a driving force from a step motor and provides a predetermined amount of power to the step motor. The output member is configured to output the operation of the input member to the sector, and the input member and the output member are operably connected to each other. , the input member and the output member are:
The input member is connected to the output member via an adjustment member that regulates the position of the output member relative to the stop position.

[Operation] Therefore, in the present invention, the relative phase between the output shaft of the step motor and the sector drive member is adjusted in parallel within the operating range of the sector drive member without changing the initial stop position of the rotor. be able to.

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

The step motor M used in the present invention is conventionally known and consists of a rotor made of a rotatably supported permanent magnet magnetized with multiple radial poles; It is composed of at least two related stators and a coil that excites the stators.

1 and 2, a pinion 2 is fixed to the tip of an output shaft 1 of a step motor M. As shown in FIGS. A base plate 4 is attached with screws to the bottom side of the base plate 3 that holds the lens, and an opening 0 for the lens opening is formed at the center of this base plate and this base plate, and an opening 0 for the lens opening is formed at the center of the base plate and the base plate. A sector chamber R for storing sectors 5, 5 is formed between them.

The sector drive lever 6 is an output member that outputs the rotational force from the output shaft 1 of the step motor M to the sectors 5, 5, and this lever is rotatably supported by a rotation shaft 3a provided on the base plate 3. It is supported by the lower surface of the step motor M so as not to slip out upward.

A sector drive wheel 7, which is an input member, is rotatably attached to the sector drive lever 6.

An adjustment pin 8 fixed to the sector drive wheel 7 engages with a groove 6b provided in the sector drive lever 6, and rotation of both 6 and 7 is regulated by this adjustment pin. The sector drive lever 6 has a sector pin 6a that penetrates the base plate 3 and engages with the groove of the sector 5.

Further, the sectors 5, 5 are rotatably supported by a pin 3b provided on the base plate 3, and are composed of two sheets arranged symmetrically, and are configured to determine the opening 0.

The sector drive wheel 7 is formed with teeth 7a that engage with the idler wheel 9, and has a pin 7c that engages with a spring 10, and is biased counterclockwise by this spring. Furthermore, the sector drive vehicle 7
A rotation determining portion 7b is formed to restrict rotation in relation to a pin 3c provided on the base plate 3 so that the step motor M operates starting from a predetermined stop position. Therefore, the initial stop position of the rotor is not changed.

The sector drive wheel 7 is an input member that receives operation from the step motor M, and also has a sector drive lever 6.
is an output member that outputs the operation of the input member to the sector 5 via the adjustment pin 8.

Further, an adjustment pin 8 fixed to the sector drive wheel 7
The diameter portion engaged with the sector drive wheel 6 and the diameter portion engaged with the groove 6b of the sector drive lever 6 are eccentric from each other, and the sector drive wheel 7 is crimped to maintain a predetermined friction. Rotatably fixed with slip torque. Therefore, by driving the groove of the adjustment pin 8 with a screwdriver or the like, it is possible to adjust the phase relationship between the tooth 7a of the sector drive wheel and the sector pin 6a of the sector drive lever. like this,
Adjustment using the adjustment pin 8 is performed using the degree determining portion 7b and the pin 3.
This is to restrict the position of the sector drive lever 6 relative to the stop position of the sector drive wheel 7 according to the position c. With this adjustment, the step motor M
The phase of the signal driving the shutter is synchronized with the phase of the position where the sectors 5, 5 of the shutter are driven.

The idler wheel 9 is a toothed portion 7a of the sector drive wheel 7.
It has a pimion 9a that meshes with the pinion 2 and a gear 9b that meshes with the pinion 2, and is rotatably supported by a rotating shaft 3d provided on the base plate 3 and supported by the lower surface of the step motor M so as not to slip out.

Further, the base plate 3 has a column 3e for mounting the step motor M, and by fixing the step motor M to the column 3e with a set screw 11, the pinion 2 and the idler wheel 9 mesh to transmit rotation. It becomes possible.

FIG. 3a shows an output signal of a drive circuit for generating a predetermined magnetic field in two coils L1 and L2 in a step motor M in which the stator and coil are configured in two sets, for example. This is a drive signal of a known bipolar drive two-phase excitation system in which the excitation currents of the coils are in the positive (+) and negative (-) directions and the excitation currents are constantly flowing through the two coils. In addition, this drive signal corresponds to the photometric information and distance information of the subject. For example, if the brightness of 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 that will be done.

Furthermore, FIG. 3b is an operational diagram of the sector 5 when driven with the pulses of FIG. 3a.

The spring 10 biases the sector drive wheel 7 counterclockwise and in the closing direction of the sector 5, and this bias force causes the rotation of the step motor M from the pinion 2 to the sector drive lever 6. This is to always shift backlash such as the clearance of the support part and the backlash of the meshing part to one direction. The biasing force of the spring 10 is appropriately set within a range that is less than the output torque of the step motor M and is sufficient to eliminate the above-mentioned backlash.

The operation of the present invention will be explained below.

First, in FIG. 1 showing the state before operation of the camera, the sector drive wheel 7 moves counterclockwise to the degree setting part 7b.
The two sectors 5, 5, which are located in positions where the and pins 3c are related to each other and are engaged with the pin 6a of the sector drive lever 6, also close the lens opening 0, and the coil of the step motor M is also energized. do not have.

In this state, the release means, photometry means, etc. of the camera are activated, and the output signal of the drive circuit is determined as shown in Figure 3a based on the brightness information of the subject, and this output signal is sequentially applied to the two coils L1 and L2. When energized, a sector opening operation is performed 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 and L2, an excitation current that is alternately reversed flows, and the pinion 2 of the step motor M rotates clockwise in steps. The rotation of the pinion 2 is transmitted to the sector 5 by the idler wheel 9, the sector drive wheel 7, and the sector drive lever 6, the sector 5 is opened, and exposure starts from the third pulse.

After that, the step motor M starts to reverse with the output signal from the 5th pulse, and from then on until the 8th pulse, the pinion 2 rotates counterclockwise to close the sector 5, and at the end of the operation of the 8th pulse. The state is the same as before the operation involving the sector drive wheel's adjustment portion 7b and pin 3c.

During the opening/closing operation, the spring 10 always biases the sector drive wheel 7 in a counterclockwise direction and pulls backlash due to clearance, backlash, etc. in one direction, so it starts rotating rapidly and stops after rotating a predetermined angle. Since the idler wheel 9, sector drive wheel 7, and sector drive lever 6 correctly follow the step operation of the pinion 2, the opening amount of the sector 5 will not be deviated due to backlash.

On the other hand, the adjustment pin 8 that connects the sector drive wheel 7 and the sector drive lever 6 can be rotated by a screwdriver or the like during the assembly process, so that both 6 and 7 can be rotated.
3b, the operations of sectors 5, 5 are translated in parallel as shown by A and B. Therefore, since the overlapping amount of the two sectors 5, 5 before operation and the aperture diameter during opening operation change, it is necessary not only to adjust the exposure amount, but also to adjust the meshing part's backlash,
It is possible to adjust the phase shift due to clearance of the rotating support part, component manufacturing error, etc. Furthermore, since the aperture diameter (diaphragm aperture) when the strobe device emits light changes depending on the strobe light emission timing determined from the distance information during strobe photography, it can be adjusted in the same way.

In the above operation explanation, the step motor M is reversed from the 4th pulse to the 5th pulse, but the timing of this reversal pulse depends on information such as photometry and distance, so when the subject is bright or when using a strobe, the step motor M is reversed. It is programmed to reverse at a position with a small number of pulses in the case of , and to reverse at a position with a high number of pulses when the subject is dark or when shooting from a distance using a strobe.

In the above embodiment, the sector drive member is configured in a lever type, but it can be similarly configured in a ring type, which is well known as a sector drive member.

Further, in the above embodiment, the step motor and the sector drive member are connected only by a gear mechanism, but in addition to the gear mechanism, there are also two levers and one
The same applies to a structure in which one lever is provided with one pin, the other lever is provided with a groove that fits the diameter of the pin, and the transmission is transmitted between the pin and the groove.

[Effect] In the present invention having the above configuration, the input member receives the driving force from the step motor and operates starting from a predetermined stop position for the step motor, so that the initial stop position of the rotor can be adjusted. By configuring the phase adjustment member without changing the phase adjustment member, phase adjustment can be achieved without changing the operating characteristics of the sector. That is, since the starting characteristics of the rotor and stator can always start the operation from the best position as a starting point, the operation of the rotor is stabilized at an early stage, and the movement of the sectors is performed smoothly. Furthermore, the input member and the output member are connected via an adjustment member that regulates the position of the output member relative to the stop position of the input member, thereby absorbing component errors and adjusting the relative phase between the step motor and the sector. In shutters where the rotational speed of the step motor is determined by built-in data, it is easy to adjust the phase of the almost parallel movement relationship, and the exposure amount and opening caused by the strobe effect caused by the phase error between the step motor and the sector can be easily adjusted. The diameter (aperture diameter) error can be easily adjusted, the structure is simple, the assembly and adjustment process is easy to work with, and it is excellent in mass production and economy.

[Brief explanation of drawings]

FIG. 1 is a plan view, FIG. 2 is a sectional view of FIG. 1, and FIG. 3 is a waveform diagram of an output signal from a motor drive circuit and a sector operation diagram. M...Step motor, 2, 9...Transmission means (2...pinion, 9...idler vehicle), 5,5
... Sector, 6, 7 ... Sector drive member, 6 ...
Output member (sector drive lever), 7... Input member (sector drive wheel), 7b... Degree determining portion, 3c... Pin, 8... Adjustment member (adjustment pin), 10... Spring.

Claims (1)

[Claims for Utility Model Registration] A sector that opens and closes a lens aperture, a step motor that rotates forward and backward, a sector drive member that drives the sector, and a transmission means that connects the step motor and the sector drive member. In the shutter, the sector drive member includes an input member and an output member, and the input member receives a driving force from the step motor and controls the step motor to a predetermined stop. The output member is configured to output the operation of the input member to the sector, and the input member and the output member are operably connected to each other. A sector opening/closing device driven by a step motor, wherein the input member and the output member are connected via an adjustment member that regulates the position of the output member relative to the stop position of the input member.