JPS60123828A - Rotation controller for motor - Google Patents

Abstract

PURPOSE:To decelerate the rotating speed of a motor to a specific level and to fix a stop position by allowing a motor control circuit for a camera to use the output of a pulse generating means fitted to the motor for power-on control. CONSTITUTION:When a reset signal A is inputted at the end of photography, a film winding motor 1 is powered on with the high output of an NOR gate 16 and a pulse B is generated. When a counter output Q7 goes up to a high level C at a specific position (right before one frame of a film is fed) close to a stop position, an AND gate 13 which receives it turns on and off according to the output of a one-shot multivibrator 12 which receives an output waveform. Consequently, the pulse interval of the NOR gate 16 is short. Namely, as the rotating speed of the motor 1 goes to higher and higher, the duty ratio of electricity feeding goes to smaller and smaller, and deceleration becomes large, so the NOR gate 16 is closed with an output Q8 at the stop position and then the motor is stopped at the specific position.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a motor rotation control device, more specifically, a rotational drive of a DC motor used for film winding in a camera or for raising and lowering a movable viewing mirror. The present invention relates to a rotation control device that controls a rotation control device.

(Prior art) In a camera that winds and rewinds film using a motor, if the 14° voltage of the DC power supply for driving the motor fluctuates, the film transport speed fluctuates, which causes variations in the stop position of the humerum. Put it away. Therefore, for example, conventionally, if a detection switch is activated before the end of film rewinding, the motor drive is stopped after a delay time corresponding to the power supply voltage from this point on, so that the motor drive is always affected by fluctuations in the power supply voltage. A device designed to stop the film at a fixed position without any trouble (Japanese Patent Laid-Open No. 57-21113
No. 1) has been proposed. However, with this conventional device, not only is the configuration complicated, but it also cannot handle problems such as changes in motor load due to changes in ambient temperature or variations in film transfer resistance. In such a case, the film stopping position will change.

For this reason, a device has been proposed that detects the film transport speed using pulses, uses a microcomputer to calculate the amount of film overrun based on this transport speed, and controls the motor stop position. (Japanese Patent Application Laid-Open No. 58-24123.

(Japanese Patent Application Laid-open Nos. 58-24124 and 58-24125), devices using such a microphone stomach computer had the disadvantage that the algorithm was complicated.

(Objective) In view of the above points, an object of the present invention is to provide a rotation control device for stabilizing the rotational speed of a motor and accurately controlling the stop position without being affected by fluctuations in power supply voltage, negative voltage, etc. I have a lot to offer.

(Summary) The motor rotation control device of the present invention generates pulses with a constant width at a period corresponding to the rotation speed of the motor, and when the motor is rotating at high speed, the duty ratio of the current flowing to the motor is small. ! Fog when the motor is rotating at low speed.
t3f[! The rotation of the motor is configured to be feedback-controlled to increase the duty ratio of the flow.

(Example) Hereinafter, the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a perspective view of an embodiment in which the motor rotation control device of the present invention is applied to a film winding mechanism of a camera. The rotation of the motor 1 is transmitted from a drive gear 2 provided at the upper end of the drive shaft of the motor 1 through an intermediate gear 3 to a gear 4 mounted on the axis KWt of the film increasing spool 5. Te1te, here.

As the spool 5 rotates K, the film 7, which has been pulled out from the film cartridge 6 and whose tip gluer part is engaged with the slit Sa1g of the spool 5, is wound up on the spool 5 as indicated by the arrow a. It is designed to be transported in the winding direction shown. At the lower end of the drive shaft of the motor 1, there is provided a disc 8 having a large number of slits 8a formed at intervals of 100 cm on its periphery. The slit 8! emits light toward the peripheral portion having 8a and b, and receives the reflected light from the slit 8!
A photoreflector 9 for detecting the motor rotational speed is provided to detect the presence or absence of the motor rotation speed. Further, a photoreflector 10 for detecting the amount of film transport is provided at a position opposite to the portion of the lower edge of the film 7 having the perforation seal 7a. ing.

The above two photoreflectors 9 and 100 output terminals are the second
It is connected to the electric circuit of the film winding device, which is a rotation control device, shown in the figure. That is, in the electric circuit shown in FIG. 2, the output terminal of the photoreflector 9 is connected to a waveform shaping circuit 11 for converting the output pulse of the photoreflector 9 generated by the rotation of the disk 80 into a trigger pulse. The output terminal of the waveform shaping circuit 11 is connected to a one-spot match biprator 12KIF for converting the trigger pulse into a pulse of a constant time width by inputting the trigger pulse. The output terminal of this one-seat multivibrator 12 is connected to one input terminal of an AND gate 13.

Further, the output terminal of the photoreflector 1o is connected to the photoreflector 10 generated by the film 70 being rolled up and transferred.
The output terminal of the waveform shaping circuit 14 is connected to the input terminal of a counter 15 for counting the output pulses of the waveform shaping circuit 14. has been done. The reset terminal of the counter 15 (R)''! When the camera release operation is completed, a temporary
"Level/1ft)" to "High" level (hereinafter +1H")
Terminal 1 to which a reset signal K is applied
9 is connected. The output terminal Q7 of the counter 15 is a terminal that changes from the ``L'' level to the 1H'' level when 7 output pulses from the waveform shaping circuit 14 are counted, and is connected to the other input terminal of the AND gate 13. There is.

The output terminal of the AND gate 13 is connected to one input terminal of the NOR gate 16. Output terminal Q of counter 15
, are terminals that change from the 'L' level to the 1H level when eight output pulses from the waveform shaping circuit 14 are counted, and are connected to the other input terminal of the NOR gate 16.

The output terminal of the NOR gate 16 is connected to the base of an NPN transistor 17 as a switching member of the motor drive circuit. The collector of the transistor 17 is connected to the positive pole of the DC power battery 18 via the motor 1, and the emitter is connected to the negative pole of the DC power battery 18.

Next, the operation of the film winding device shown in FIGS. 1 and 2 will be explained with reference to the time chart shown in FIG. 3. When the release operation of the camera is completed, the terminal 19 temporarily becomes ``H'' level by the operation of a sequence control circuit (not shown), and the reset signal shown in FIG. Therefore, at this time, the output terminals Q7 and Q8 of the counter 15 go to the ``L'' level.The output of the NOR gate 16 goes to the @Hl'' level due to the 1L'' level of the output terminals Q, Q, of the counter 15, so the transistor 17 goes to the ``L'' level. Electricity is established and motor 1 rotates.

When the motor 1 rotates, the disk 8 rotates in the direction of the arrow A, and the % photoreflector 9 generates pulses depending on the presence or absence of the slit 81. Further, the rotation of the motor 1 is transmitted to the film take-up spool 5, and the film 7 is wound up and transferred in the direction of the arrow a, and the photoreflector 10 generates pulses depending on the presence or absence of the par-7 olathe film 7a. do. The output pulse from the photoreflector 9 according to the presence or absence of the sleeve 8a is waveform-shaped by the waveform shaping circuit 11, and the fifth
It is assumed that the pulse shown in F”1 (B).Waveform shaping circuit 1
The output pulse of 1 is a one-shot multivibrator 12
When guided to the input terminal IN, the one-shield multivibrator 12 is triggered by the output pulse of the waveform shaping circuit 11 and sends out a 1H'' level pulse with a constant time width from the output terminal OUT to the AND gate 13. The output pulse from the photoreflector 10 according to the presence or absence of the par 7'' laser beam 7a is also waveform-shaped by the waveform shaping circuit 14, and then led to the four input terminals CLK of the counter 15. 15 is sequential par 7
Count the number of 7a. Before counting the number of par 7 oscillators 7a to 7, the output terminals Q, Q8 of the counter 15 are at the ``L'' level, so the transistor 17 continues to be conductive and the motor 1 continues to rotate. Therefore, the output pulse of the one-line multivibrator 12 based on the output of the photoreflector 9 accompanying the rotation of the disk 80 is blocked by the AND gate 13. In this state, the film 7 is further transferred in the direction of the arrow a, and the seventh par 7 oresian 7a is
When detected by the o-reflector 10, the output pulse of the waveform shaping circuit 14 based on the seventh par-7 oscilloscope 7a is inputted to the clock input terminal CLKK of the counter 15, so that the output terminal Q of the counter 15, is @H″
At this time, Figure 3 (C), (
As shown in FIG.
The signal is sent to one input terminal of 6. When the output pulse of the one-shot multivibrator 12 is guided to the NOR gate 15, the other input terminal of the NOR gate 16 is still held at the 'L' level (see FIG. 3 (G)), so the NOR gate 16, as shown in FIG.
2 output pulse 0 constant time width w Hn level is 1L" level of the output pulse of NOR gate 16 tx t),
The "L" level of the output pulse of the one-shot multivibrator 12 corresponds to the 1H" level of the output pulse of the NOR gate 16.

From the NOR gate 16, an inverted signal of the output pulse of the one-striped multivibrator 12 is transmitted to the transistor 1.
7, transistor-17 connects to NOR gate 16
The motor 1 is repeatedly turned on and off depending on the output of the NOR gate 16, and the motor 1 rotates with a drive current proportional to the output of the NOR gate 16. That is, at the point when the seventh par 7' ore of film O is counted 7m, the driving current of the motor 1 is switched to the pulse current that is the inversion of the output of the multivibrator 12, so the motor rotates 10 times. Slow down.

By the way, the period of the output pulse of the photoreflector 9 that detects the rotational speed of the motor 1 is such that when the rotation of the motor 1 becomes high speed due to fluctuations in the voltage of the power supply battery 18, K becomes short and the speed becomes low. Sometimes it becomes long, so if we look at this in terms of the output of the NOR gate 16, we can see that the output pulse of the NOR gate 16 is 'H' with respect to the 'L' level of a certain time width.
The time width of the level becomes short when the rotation speed of the motor 1 becomes high, and becomes long when the rotation speed of the motor 1 becomes low. In other words,
"Turn on the transistor 17 of the NOR gate 16"
The duty cycle of the output pulse at the I-1" level becomes smaller when the motor 1 rotates at high speed, and increases when the motor 1 rotates at low speed. Therefore, when the motor 1 is rotating at high speed, the output of the NOR gate 16 causes the transistor 17 to The conduction time becomes shorter and the drive current of motor 1 decreases,
When the motor 1 rotates at a low speed, the transistor 17
The conduction time of the motor j1 becomes longer and the drive current of the motor j1 increases. In this way, the rotational speed of the motor 1 is decelerated by the pulse current when the 707th perforation of the film is counted, and at the same time feedback is applied to the drive flow of the motor 1, so that when the motor 1 is at a relatively high speed, it is at a low speed. Rotation is controlled to high speed when the speed is low. After that, when the eighth perforation of the film 7 is detected by the photoreflector 10, the output pulse of the waveform shaping circuit 14 based on the eight perforations is input to the clock output terminal CI/K of the counter 15. As a result, the output terminal Q8 of the counter 15 becomes H" level as shown in the third interval, and at this time, the output of the NOR gate 16 becomes the output of the AND gate 13, as shown in FIG. Therefore, the transistor 17 becomes non-conductive, the power supply circuit of the motor 1 is cut off, and the motor 1 stops rotating. The rotational speed of the motor 1 is determined when the output terminal Q7 of the counter 15 reaches the 'H' level and then the output terminal Q8 reaches the 'H' level.
By the time it reaches the 'H' level, the speed is stabilized at a constant speed by the feedback rotation control described above, and therefore, when the output terminal Q of the counter 15 reaches the 'H' level and the driving φh current is cut off. , the rotation of the motor 1 will stop after a certain period of time from this point.

To explain this using the film transport speed diagram shown in FIG. Electricity is established, the motor 1 rotates, and the winding transfer of the film 7 - bζ is started.In FIG. Voltage of power supply battery 18, 6
% is high. When the voltage of the power supply trace 18 is low, if winding and transport of the film 70 is started at the point of 1°=0, the film 7 will be transported at a constant speed v1 with a force of 1. , eye brim - 7 on bt time 1 - = 1. When this is detected and counted by the counter 15, the above-mentioned feedback is applied to decelerate the film 7 and control it to a constant speed V. After the constant speed V, at time t = ζ1, the 8th value <-7 ores,
When detected at y6 and counted by counter 15,
The power supply to the motor 1 is cut off, and the film 7 is stopped being transported. In addition, if the voltage of the power supply battery 18 is high, the film 7 starts winding and transfer when 1=0.
It will be transported at a constant speed V, which is faster than the above speed v1, but the time point 1 when counting the 7th (from the time 1 when counting the -folation 1 = 1b to the 8th time) the -folation =1. The speed up to □ is similarly controlled to constant speed v1. Then, counting the 8th bar 7 oresi, at this point 1 = 1. , the power to the motor 1 is cut off and the film 7 stops being transported. In this way, when the voltage of the power supply battery 1B is high and therefore the film transport speed is high, the voltage of the power supply battery 18 is low and the film transport speed is low. Before counting 8 pieces of film 7a, the speed is controlled to a constant speed v1 (~), so after counting the 8th film 7a, the film 7
The amount of transfer until the film 7 completely stops is confined to the area shown with diagonal lines in FIG. The stopping position of is always constant.

In other words, the amount of winding of one frame of the film 7 is always constant, and stable frame winding is possible without being affected by fluctuations in the voltage of the power source 18. is performed, and the interval between the shooting screens becomes accurate.

The motor rotation control device of the present invention is applicable not only to a film winding device but also, for example, to a mirror drive device for raising and lowering a movable observation mirror of a camera.

FIG. 5 shows the motor rotation control device of the present invention.
FIG. 2 is an exploded perspective view of an embodiment applied to a mirror drive device.

The movable observation mirror 27 of the camera is rotatably supported around a support shaft 27a, and is
It has descended to a position inclined at an angle of 5 degrees (see Figure 6).
After the shutter release, it rises to an almost horizontal position (6th
(see figure (B)), the photographing optical path is opened. The driving control for raising and lowering this movable observation mirror 27 is performed by a motor 21. The drive gear 22 that is integrally provided on the drive shaft of the motor 21 meshes with the gear 24 that is integrated with the rotating shaft 25a of the eccentric cam 25 via the intermediate gear 23, so that the rotation of the motor 21 causes the eccentric cam 25 to
will rotate in the direction of arrow C. The eccentric cam 25 is located near the side of the movable mirror 27, and when it rotates in the direction of the arrow C, the large diameter cam portion 25b protrudes to the side of the mirror frame of the movable mirror 27 and becomes integral with it. It is adapted to engage a provided drive pin 28. Further, a reflecting disk 26 is provided integrally with the rotation 41125a of the eccentric cam 25. This reflective disk 26 has a partially arc-shaped light shielding portion 2 on the periphery of one side of the disk made of a high reflectance material.
By forming 9a and 29b, this light shielding part 29a
, 29b are formed, and reflective portions 26a and 26b are formed at approximately 180 mm opposite peripheral edge positions. Two 7-axis reflectors 50, 51 are arranged in parallel at a distance from each other at a position facing the peripheral edge of the reflective disk 260.

The output terminals of the photoreflectors 50 and 51 are connected to the electric circuit of the mirror drive device shown in Fig. 7.

That is, in the electric circuit shown in FIG.
The output terminal of the 7-channel 7-rector 5o is the waveform shaping circuit 32.
The output terminal of the waveform shaping circuit 32 is connected to the clock input terminal cp of a D-type flip-flop circuit (hereinafter referred to as D-FF) 33. Further, the output terminal of the second 7-o-reflector 51 is connected to the waveform shaping circuit 54, and the output terminal of the waveform shaping circuit 54 is connected to the D-FF5.
It is connected to the clock input terminal CpK of No. 5. D-FF
The D input terminals 53 and 55 are connected to a voltage terminal 36 at which 0 human power becomes 1H'' level, and the reset terminal R is a terminal 37 to which a reset signal of ``H'' level is temporarily applied before the start of shooting and after the end of shooting. It is connected to the.

The output terminal Q of the D-FF 55 is connected to the other input terminal of the AND gate 58, and the output terminal of the AND gate 38 is connected to one input terminal of the NOR gate 59. The output terminal Q of the D-FF 55 is connected to the NOR gate 59.
The output terminal of the NOR gate 59 is connected to the base of an NPNall transistor 40 as a switching element provided in the motor drive circuit. The collector of the transistor 40 is connected to the positive pole of the power battery 41 via the motor 21, and the collector is connected to the negative pole of the power battery 41. Further, the motor 21 is provided with a round PNP type transistor 42 that performs braking, and the emitter and collector of the transistor 42 are connected to both terminals Km of the motor 21. The base of this transition sadness 42 is the above D-FF! 15 output terminals Q are connected via an inverter 43.

Further, the connection point between the above-mentioned sensor 21 and the transistor 21 is connected to a waveform shaping circuit 45 via a motor rotation speed detection capacitor 44 for detecting GI noise according to the rotation speed of the motor 21. The output terminal of the waveform shaping circuit 45 is the one-seat multi-pibrator 460 input terminal I.
NK is connected. An output terminal OUT of the one-shot multivibrator 46 is connected to one input terminal of the AND gate 58.

Next, the operation of the mirror drive equipment shown in FIGS. 5 to 7 will be explained. When the shutter release operation is performed, first, at the start of photography, a reset ID signal is applied from the terminal 37 to the reset terminals R of the D-FFs 55 and 55 by the operation of a sequence control circuit (not shown), and the D-FFs are reset.
The outputs of 55 and 55 are both @I and II level. Therefore, the output of the NOR gate 59 becomes "H" level, the transistor 40 becomes conductive and the motor 21 is energized, and the motor 21 starts rotating. When the motor 21 rotates, rectified waveform noise as shown in the eighth row is generated at the terminals of the motor 21, and this is detected at the input terminal of the waveform shaping circuit 450 through the capacitor 44. The noise is waveform-shaped into a pulse as shown in FIG. 8 (6). The output pulse of this waveform shaping circuit 45 is a one-shot multivibrator 46K.
It is converted into a pulse with a constant time width. The period of the output pulse of this dot multivibrator 46 is:
As in the case of the previous embodiment, due to fluctuations in the voltage of the ItgJ battery 41, etc., the time becomes shorter when the motor 21 is rotating at a high speed, and becomes longer when the motor 21 is rotating at a low speed.

Further, when the motor 21 starts rotating as described above, the eccentric cam 25 rotates in the direction of arrow C as the gears 22 to 24 rotate. Even if the eccentric cam 25 rotates, at the beginning of the rotation, the eccentric cam 25 does not come into contact with the drive bin 28 that is integrated with the movable mirror 27, as shown in the sixth rotation, so the movable mirror 27 is in a lowered state. However, when the eccentric cam 25 rotates further and its large diameter cam portion 25b approaches the drive pin 28, the large diameter cam portion 25b collides with the drive pin 28 and pushes it up. 27 rotates counterclockwise around the support shaft 27a and rises. The largest diameter portion of the large diameter force ram portion 25b of the eccentric cam 250 is formed in an arc shape centered on the rotating shaft 25a.

Even if the eccentric cam 25 continues to rotate after the movable mirror 27 has once risen to a horizontal position as shown in FIG. Retained.

By the way, as the eccentric cam 250 rotates, the reflective disk 2
6 also rotates in the direction of arrow C, but when the movable mirror 27 rises, the reflecting disk 26 is caused by the rotational pressure to cause the reflecting portion 26 to move upward.
The light shielding part 29a is 7 meters from a to 7 rectifiers 30.51 K
This results in an M-th opposing state. And the movable mirror 27
Immediately before the reflecting portion 26b of the reflecting disk 260 is raised by the eccentric cam 25, the first photoreflector 30 detects the reflecting portion 26b, and its rising output is guided to the waveform shaping circuit 32. ) -FF
33, and the output terminal Q of D-FF53 is nulled to IIH" level. When this 1H" level signal is led to the other input terminal of ANDGOO) 3B, AND gate 38 outputs the one-shot multi /< Since the output pulse of the ibrator 46 is passed through and sent to one input terminal of the Noah gate 39, the output pulse of the Noah gate 59 is inverted. The transistor 40
Lead to 0 pace. Then, since the transistor 40 is repeatedly turned on and off by the output of the NOR gate 39, the drive current of the motor 21 becomes a constant current, and the motor 21 is decelerated. At the same time, the pulse current from this NOR gate 39 is as described in the previous embodiment.
If the rotational speed of the motor 21 is high due to voltage fluctuations of the power supply battery 41, etc., the duty cycle of the pulse that makes the transistor 40 conductive is %/IS; if the rotational speed of the motor 21 is low, the duty cycle is large. Therefore, the rotational speed of the motor 21 is controlled at a constant speed and pressure after deceleration. In other words, the motor 21 is decelerated just before the movable mirror 27 is pushed up by the eccentric cam 25 colliding with the driving bin 2 and completes its ascent, so the movable mirror 27 moves relatively slowly from just before the ascent is completed. Constant speed pressure control.

Then, when the movable reflection mirror 27 has completely completed its ascent, the reflection portion 26b of the reflection disk 260 is detected by the second 7-point rectifier 31.
The rising output of the o-reflector 31 is waveform-shaped by the waveform shaping circuit 34, and this waveform-shaped pulse is applied to the D-FF.
35, the output terminal Q of D-FF'55 becomes ``
'H'' level. Then, the output of the Noah sheet 39 goes to the l L jl level regardless of the output of the AND gate 38, and the transistor 40 becomes non-conductive Kl and the power supply circuit of the motor 21 is cut off. When the output terminal Q becomes @H” level, the braking transistor 42
conducts, and at this time, both terminals of the motor 21 are short-circuited and braking is applied, so the motor 21 stops and the movable mirror 27 stops at the above-mentioned raised completion position. As mentioned above, since the rising speed of the movable mirror 27 immediately before completing its ascent is in a constant speed state where it is decelerated, a land may occur when the movable mirror 27 completes its ascent.
c <, and its stopping position is always a constant position.

After the shooting is completed, the reset signal is again led from the terminal 37 to the I noset terminal R of the D-FF 33, 35, so the D-FF
F33. 35 (D output terminal Q becomes ``L'' level -
As a result, the transistor 40 becomes conductive and the motor 21 is restarted to be driven, so that the eccentric cam 25 rotates in the direction of arrow C and the movable mirror 27 descends.

When the movable mirror 27 is lowered, the same operation as when it is raised is performed. Immediately before the movable mirror 27 completes its descent, the reflecting portion 26m of the reflecting disk 260 is first detected by the first photoreflector 30, so at this time, the reflection disk 260 is detected by the first photoreflector 30.
The transistor 40 is turned on and off by a pulse obtained by inverting the output of the one-shot multi-novel ibrator 46', and the motor 21 is decelerated to a constant speed, and the movable mirror 21 is decelerated to a constant speed.
7 approaches the point at which the descent is completed at a relatively slow constant speed. Subsequently, when the reflecting portion 26m is detected by the second 7-point collector 31, the transistor 40 becomes non-conductive and the transistor 42 becomes conductive, so that the motor 21 suddenly stops and the movable mirror 27 remains in the fixed position. Stop. Therefore, even when the movable mirror 27 completes its descent, it does not bounce like when it completes its ascent, and it always stops at a constant position regardless of fluctuations in the voltage of the power source battery 41, etc.

Furthermore, it goes without saying that the motor rotation control device of the present invention can be applied not only to making the motor stop position accurate, but also to simply making the motor rotate at a constant speed. will be explained next.

FIG. 9 is an electric circuit diagram of another embodiment in which the motor rotation control device of the present invention is applied to a film winding device. The film winding device shown in FIG. 9 is not provided with a means for detecting the par 7 orifice position in the film winding device shown in FIG. 2. That is, 7 in Figure 2
To explain only the circuit configuration that replaces the o-reflector 10, the waveform shaping circuit 14, and the d counter 15, the trigger switch 51 closes in synchronization with the end of the shutter release.
-m is connected to a voltage terminal 52 to which an "H" level signal is applied, and the other end of the trigger switch 51 is grounded via a resistor 53. trigger switch 51
The connection point between the and the resistor 53 is connected to the input terminal IN of the one-shot multi-vibrator 54, and the output terminal OUT of the one-shot multi-vibrator 54 is connected to the inverter 5.
5 to the other input terminal of the AND gate 13. In addition, the trigger switch 51 and the resistor 53
The connection point is the Noah gate 16 via the input/<- terminal 56.
is connected to the other input terminal of Other configurations are similar to the circuit shown in FIG.

Next, to explain the operation of the above-mentioned film winding device, first, when the shutter release is completed, the trigger switch 51bz is closed in synchronization with this, and the one-shot multi-node (ibrator 54 is once set to the "H" level) by kneading. Therefore, the output of Innoku Ichiyo 55 is a certain period of time when this one-shot multivibrator 54 is at "H" level.
The output of the inverter 56 also goes to the "L" level due to the closing of the trigger switch 51, so at this time, the output of the NOR gate 16 goes to the 1H" level, and the transistor 17 becomes conductive, causing the motor 1 to rotates and winding of the film begins. Since a large starting torque is required for the motor 1 at the start of film winding, the motor 1 is thus rotated by a steady drive current. When the motor 1 rotates, the rotational speed of the motor 1 is detected as a pulse by the 7-torque 7-rector 9, which is waveform-shaped by the waveform shaping circuit 11, and then converted into a pulse with a fixed time width by the one-piece dot multivibrator 12. However, while the output of the inverter 55 is at the bPL'' level, the output pulse of the one-seat multivibrator 12 is blocked by the AND gate 13. When the output power of the inverter 55 reaches the "L" level, the output of the inverter 55 becomes "H" level.
At this time, the AND gate 13 leads the output pulse of the one-shot multivibrator 12 to one input terminal of the NOR gate 16, so the output pulse of the one-shot multivibrator 12 is set to the level as the output of the NOR gate 16. An inverted pulse is obtained, which turns the transistor 17 on and off.

Therefore, at this point, the drive current of the motor 1 becomes a pulse current, and if the rotation of the motor 1 is relatively high due to fluctuations in the voltage of the power supply battery 18 as described above, the pulse current that makes the transistor 17 conductive is generated. The duty cycle is small, and when the rotation speed of motor 1 is low, the duty cycle becomes large, so as soon as motor 1 decelerates, it is immediately controlled to rotate at a constant speed, and the film is rotated at a constant speed that has been decelerated from the start of winding. transported at high speed. When a portion of the film winding is completed, the trigger switch 51 is opened. As a result, the output of the inverter 56 is
becomes H'' level, and the output of the Noah gate 16 becomes w L s
Since the transistor 17 becomes non-conductive, the motor 1 stops rotating and winding and transporting the film is stopped.

In this way, in the case of this film winding device, after the start of the desktop transfer of the film, the motor 1 is driven by a pulse current and rotates at a constant speed, so for example, if the first pulse of the motor is too strong, the film Such an accident can be prevented by taking care not to damage the film cover when winding up the final frame.

In the embodiment of the film winding device described above, in order to detect the rotational speed of the motor 1, the disk 8 having a slit 8a is directly taken from the drive shaft of the motor 1, and this is detected by the photoreflector 9. However, the rotational speed of Chiyo 1 is increased by a speed increasing mechanism such as a gear, and a signal proportional to the rotational speed of motor 1 is detected at this increased speed. Based on this signal, we obtain a pulse current to drive motor 1.
For example, according to a device that performs even more precise motor constant speed control, after the motor rotates, the 11 drive current becomes a pulse current, and the energization time due to this pulse changes depending on the rotation speed of the motor. Since feedback is applied, the motor rotation speed is slowed down and controlled to a constant speed without being affected by fluctuations in power supply voltage, etc., making it possible to perform more accurate and stable motor rotation control, and also to stop the motor. Since it can always be stopped in fixed position, it can be widely applied to, for example, film winding devices, mirror drive devices, or other drive devices, and furthermore, the structure can be provided easily and inexpensively. Demonstrates excellent effects.

[Brief explanation of drawings]

1 is a perspective view of a motor rotation control device showing an embodiment of the present invention, FIG. 2 is an electric circuit diagram of the motor rotation control device shown in FIG. 1, and FIG. 3 (8) ~n represents a time chart of signal waveforms in each part of the electric circuit shown in FIG. 2 above, and FIG. 4 represents the film transport speed controlled by the motor rotation control device shown in FIG. 1 above. 5 is an exploded perspective view of a motor rotation control device according to another embodiment of the present invention, and FIG. 6 is an exploded perspective view of a motor rotation control device according to another embodiment of the present invention. FIG. 7 is an electric circuit diagram of the motor rotation control device shown in FIG. 5, and FIGS. 8 (A) and (B) are the 5 is a time chart of the output waveform of the waveform shaping circuit 450 in the electric circuit shown in FIG. 5. FIG. 9 is an electric circuit diagram of a motor rotation control device showing still another embodiment of the present invention. 1.21 - Motor 9 - River @ 11 @ 7 O-reflector (motor rotational speed detection means 〇 12.46... One-shot multivibrator (pulse generation circuit) 17.40... Transistor (switching ym material > 1
8.41...DC power supply battery 13.58...AND gate (control circuit) 15.e.
... Counter (#) 16.39 ... Noah gate (control circuit) 33, 35
...D-FF (*') 44 ... Capacitor (motor rotation speed detection means) 54 ... One-shot multivibrator (control circuit)

Claims (1)

[Claims] A motor drive circuit that supplies DC power to the motor to drive the motor when the switching member provided in the power supply circuit of the motor is electrically connected; A motor rotation speed detection means that generates a trigger pulse at a cycle corresponding to the speed; a pulse generation circuit that generates a short constant width pulse each time it receives the trigger pulse; Control that makes the switching member conductive regardless of the pulse width, makes the switching member non-conductive for a time corresponding to the pulse width of the pulse generation after the motor rotates, and makes the switching member conductive for a time other than the pulse width. A motor rotation control device comprising a circuit and.