JPH025262A - Floppy disk drive - Google Patents

Abstract

PURPOSE:To keep a fixed rotational frequency even in case the fluctuation is caused to the load applied to a disk rotary driver, the temperatures, etc., by detecting the change of the rotational frequency of a spindle via a circuit different from a controller for rotational frequency for a motor itself. CONSTITUTION:A pulley 12 is fixed to a spindle 11 which drives a floppy disk and coupled to a minor pulley 15 of a DC motor 13 via a belt 14. A motor control circuit 16 is connected to the motor 13 to detect the rotational frequency of the motor 13 and to keep this rotational frequency at a fixed level. While an index detecting part 17 is added to the pulley 12 so as to output a signal for each revolution of the pulley 12. The index cycle of the part 17 is detected by a counter 18 and fed back to the circuit 16. Thus the rotational frequency of the motor 13 is corrected by a slight extent. Then it is possible to obtain a disk driver that has the reduced fluctuation of the rotational frequency of the spindle 11 which is caused by the load, temperatures, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a disk rotation drive device and a floppy disk drive equipped with the disk rotation drive device.

<Prior art> Conventional technologies include those described in JP-A No. 59-121659, JP-A No. 59-127268, JP-A-62-28991, and Utility Model Application No. 62-63866. be.

As shown in Fig. 2, a drive I/NO 2 is installed on the main shaft 1 for rotating the disk, and a separately installed DC motor 3 is used to drive the disc.
It is known that the main shaft is rotated via a belt 4 or the like, and the speed of the motor itself is controlled by detecting the rotational speed of the motor.

FIG. 2 is a rear perspective view of a conventional floppy disk drive.

<Problems to be Solved by the Invention> However, in the conventional separately installed disk rotation drive device, (a) the number of revolutions of the motor 3 is detected and the motor 3 itself is controlled; changes, and the reduction ratio of the main shaft pulley 2 and the pulley of the motor 3 changes.

(b) A control circuit with a simple configuration as shown in Figure 3 (
When using a bridge servo (generally called a bridge servo), the coil 3a of the motor 3 moves in the magnetic field inside the motor 3, and the voltage generated at this time (hereinafter referred to as back electromotive force) is transmitted to the amplifier 5 as shown in Figure 3. The voltage applied to the motor 3 was detected and controlled by the control truss sister 6, thereby controlling the rotation speed of the motor 3. However, as shown in FIG. 4, there is a coil 3a in the isotemporal tract of the motor 3.
There is a resistor 3b, and the back electromotive force e generated within the motor 3
cannot be taken out accurately from the terminal 3C of the motor 3, resulting in poor detection accuracy and problems in that the rotational speed is not constant or changes due to the force applied to the motor 3. Another problem was that the load changes depending on whether the floppy disk drive is placed horizontally or vertically, resulting in a change in rotational speed.

(c) In addition to these, is there a sporadic frequency in the motor? In the method of detecting the rotational speed of a motor by attaching an tta, a method that uses charging and discharging using an inexpensive resistor or capacitor as a reference for the rotation period has often been used, but in this case, it is resistant to load fluctuations. Since it is based on a capacitor/resistance, it has the problem that it is easily affected by temperature and humidity and the rotation speed changes.

Therefore, the present invention is intended to solve these conventional problems, and its purpose is to maintain the rotational speed of the disk rotation drive device even if there are fluctuations in the load, temperature, etc. on the disk rotation drive device. The aim is to keep it constant.

Means for Solving the Problems> In order to solve the above problems, the separately installed disk rotation drive device of the present invention detects the rotation speed of the motor that rotates the main shaft of the disk rotation drive device and controls the speed of the motor. The control circuit is characterized in that, in addition to detecting the rotation speed of the motor for 6J9p, the rotation speed or rotation period of the main shaft that rotationally drives the disk is detected, and the rotation speed of the motor is finely adjusted.

When a separately installed disk rotation drive device configured as described above is driven, even if factors that cause the motor rotation speed to fluctuate are added, a circuit separate from the motor's own rotation speed control controls the spindle rotation speed. It detects changes and corrects the motor rotation speed by a small amount, so it can maintain a stable rotation speed.

<Example> The present invention will be explained below based on Examples.

FIG. 1 is a schematic side view and a control block diagram of a separate disk rotation drive device of the present invention.

Pulley 1 is attached to the main shaft 11 that rotates the floppy disk.
2 is fixed, and a DC motor 1 is connected via a belt 14.
It is connected to the small pulley 15 of No. 3. DC motor-13
A motor control circuit 16 is connected to the DC motor 13 to detect its rotational speed and keep the rotation of the DC motor 13 constant. On the other hand, the boolean I7-12 is provided with an index detector 17 that outputs one signal every time the pulley 12 rotates once. And index detector 1
The output of 7 is 114 times the counter 18 which detects one rotation period of the pulley 12.

In FIG. 1, a counter 18 detects the index period of an index detector 17 provided in a boot 12 and divides it into normal, short, even shorter, longer, even longer, etc. This signal is fed back to the motor control circuit 16 and a switch is operated according to the speed to control the motor 13.
Change the resistance based on the rotation speed. In this way, even if the motor control circuit 16 has a simple configuration as shown in FIG. 3 by detecting the index period with the counter 18 and slightly correcting the rotation speed of the motor 13, the main shaft It is possible to provide a separate disk rotation drive device with little variation in rotational speed.

Note that if the CPU is used instead of the counter 18 to control the floppy disk drive and the motor rotation speed, there will be almost no cost increase for motor control. When applied, the effect is great, and even if a separate motor is used, the reliability of the floppy disk drive does not deteriorate, making it possible to provide an inexpensive and highly reliable floppy disk drive.

<Effects of the Invention> As explained above, this separately installed disk rotation drive device uses a separately installed motor and is capable of handling load changes, posture differences,
The control circuit is resistant to changes over time, and the control circuit can be simplified, while the contradictory problems of increasing the reliability of the floppy disk drive device and reducing costs can be overcome. It can be configured using an inexpensive bridge servo type control.

This is the parent diagram. Fig. 3 is a control circuit diagram of the motor, and Fig. 4 is an isotemporal road surface of the motor.

・Spindle ·pulley ・DC motor ·belt ・Small pulley ・Motor control circuit ・Index detector ·counter that's all Applicant: Seiko Epson Corporation Agent: Patent attorney Kisanbe Suzuki fm 1 person

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention. Figure 2 is a second oblique view of the back of a floppy disk drive. Figure 1 Figure 3 Figure 4

Claims (3)

[Claims] (1) In a control circuit that detects the rotation speed of the motor that rotates the main shaft of the disk rotation drive device and controls the speed of the motor, in addition to the rotation speed detection for controlling the motor, A floppy disk drive that detects the rotation speed or rotation period and finely adjusts the motor rotation speed. (2) A floppy disk drive characterized by being equipped with the disk rotation drive device according to item 1. (3) A floppy disk drive characterized in that a reference signal for detecting a rotation period is shared with a reference signal for a control circuit of the floppy disk drive.