JPH01176366A - Floppy disk drive device - Google Patents

Abstract

PURPOSE:To speedily return to a constant speed revolution by always supervising the number of revolution and operating again a slow-up means with a demodulating means when a stepping motor steps out. CONSTITUTION:The device is composed of a stepping motor 6 to drive a floppy disk 5, a slow-up means to execute the slow-up of the above-mentioned floppy disk 5 at a revolution starting time, a revolution number detecting means 7, which detects the revolution number of the floppy disk 5, and a demodulating means 8 to execute again the slow-up at a stepping motor stepping-out time. Thus, the revolution number is always supervised by the revolution number detecting means 7 and even when the stepping motor 6 executes the step-out, the constant speed revolution can be speedily recovered by operating again the slow-up means with the demodulating means 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a floppy disk drive device.

2. Description of the Related Art In general, a disk drive motor in this type of floppy disk drive apparatus employs a DC servo motor 2 to drive a floppy disk 1, as shown in FIG. This DC servo motor 2 is driven by a drive circuit 3, and its drive control is input to an FG multiplied signal current control circuit 4 of an FG pattern, and this current control circuit 4 controls the drive circuit 3. ing. That is, speed control (current control, voltage control) is performed by feeding back the FC signal and changing the current and voltage via the rotation speed control IC.

Problems to be Solved by the Invention A feedback control circuit for a DC servo motor uses a motor rotation speed control IC, a Hall IC, etc., and is quite complex, has a large number of parts, and is expensive.

Further, when a DC servo motor is used, the rotation speed is generally 30 Orpm±1%, and the rotation speed fluctuations are large.

・Means to solve the problem A stepping motor that drives a floppy disk,
The apparatus includes a slow-up means for slowing up the floppy disk when the rotation starts, a rotation speed detection means for detecting the rotation speed of the floppy disk, and a demodulation means for slowing the stepping motor up again when the stepping motor loses synchronization.

Operation Stepping motors are generally not used in this type of floppy disk drive device because of their tendency to jerk, but their use becomes possible by adding inertia. The rotation speed is constantly monitored by the rotation speed detection means, and if the stepping motor steps out of step, the demodulation means can operate the slow-up means again to quickly return to constant speed rotation. .

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 3. First, a stepping motor 6 is used to drive the floppy disk 5. The stepping motor 6 or the floppy disk 5 is provided with an index 7 as rotation speed detection means, and the index 7 is connected to a one-chip microcomputer 8. An oscillator 9 is connected to this one-chip microcomputer 8. Further, the one-chip microcomputer 8 includes a drive circuit 1.
0 is connected, and this drive circuit 10 is connected to the stepping motor 6.

In such a configuration, the rotation speed of the disk rotation motor of the floppy disk drive device is generally 300 r.
, pm, and the time required for one rotation of the floppy disk 5 is 200 m5. The stepping motor 6 rotates by a predetermined angle (stepper angle) by passing a direct current through the stator windings and sequentially switching the windings through which the current flows.

The one-chip microcomputer 8 has a built-in ROM and RAM, and the ROM has a built-in disk drive program. The program will be explained based on FIG. First, when starting the stepping motor 6, a large torque is required, so a slow-up operation is performed by a slow-up means that outputs the output pulse width to the output boat so that the output pulse width is initially large and gradually becomes smaller.

After the slow-up operation has been performed for a certain period of time, a constant speed rotation pulse is output to the output boat, and this state continues until the first index signal is detected. resets the pulse counter when the constant speed rotation pulse width time is reached. Then, the pulse counter is incremented in the constant speed state, and when the count reaches the count value of one rotation, it is checked whether or not the next index signal is detected while the constant speed rotation state is maintained. If the next index signal is detected at this time, it means that constant speed rotation is being performed normally.

However, if the next index signal is not detected in this state, it means that the stepping motor 6 is out of step. At this time, the counter is incremented by the number of pulses exceeding the specified number. Then, when the next index signal is detected, the demodulation means sets the optimum pulse width for the oversized counter value and causes the first slow-up operation to be performed again.

An example of such speed control will be explained with reference to the timing chart of FIG. 3. This shows the timing of the output pulse with a step angle of 1.8° and the index signal. That is, after counting 200 pulses, the microcomputer senses the second index signal, and if it detects the index signal, it determines that it is rotating at a constant speed, and if it cannot detect it, the stepping motor 6 is out of step. It is determined that the engine is running at a constant speed, and then jumps to the optimal slow-up routine and returns to constant speed rotation.

Note that according to the above-mentioned means, one of the stepping motors 6
Since the index signal comes only once per rotation, it is effective to adopt the structure shown in FIG. 4. That is, n equal-angle reflecting plates 12 are provided on the side surface of a rotor 11 driven by a stepping motor 6, and these are detected by a photoreflector 13. As a result, the motor rotational state is monitored n times per rotation.

Therefore, the motor rotation can be maintained at a constant speed for a short period of time.

Theoretically, the stepping motor 6 has 1 pulse and 1 stepper angle, so for a stepper angle of 0.9°, 1
Since the rotation is a 400m magnetic pulse, the rotation speed accuracy is (1/400) x 100% = 0.25%,
I) A highly accurate motor rotation speed can be obtained for the C servo motor.

Effects of the Invention As described above, the present invention includes a stepping motor for driving a floppy disk, a slow-up means for slowing up the floppy disk when rotation starts, and a rotation speed detection means for detecting the rotation speed of the floppy disk. Since the stepping motor is configured to include a demodulating means that slows up the stepping motor again when the stepping motor goes out of step, the rotational speed is constantly monitored by the rotational speed detection means, and when the stepping motor goes out of step, the demodulation means slows up the stepping motor again. By operating it, it is possible to quickly return to constant speed rotation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a flowchart, Fig. 3 is a timing chart, Fig. 4 is a perspective view showing a modified example, and Fig. 5 is a block diagram showing a conventional example. It is. 5...Floppy disk, 6...Step motor, 7...Index (rotation speed detection means) Application Person: Tokyo Electric Co., Ltd.

Claims (1)

[Claims] A stepping motor that drives a floppy disk,
A floppy disk characterized by comprising: slow-up means for slowing up the floppy disk when rotation starts, rotation speed detection means for detecting the rotation speed of the floppy disk, and demodulation means for slowing up again when the stepping motor steps out. drive device.