JPS60143489A - Floppy disk device - Google Patents

Abstract

PURPOSE:To execute a motor by single power source and to reduce driving heat generation by executing feeding by one track by two-step angle of a stepping motor, by driving the stepping motor by one or two phase excitation, and constituting so that phase excitation at the time of stopping the motor on the track will be one phase. CONSTITUTION:When three pulses are inputted, coils phi1 and phi2 are conducted when the first pulse is inputted, the coil phi1 is not conducted after fixed time (t)sec, and only the coil phi2 is conducted. When the second pulse is inputted, the coil phi2 and a coil phi3 are conducted, the coil phi2 is not conducted after fixed time (t)sec, and only the coil phi3 is conducted. When the third pulse is inputted, conduction of the coil is switched sequentially in the same way. Between input pulses, the coil and the switched fixed time (t) are about the half of access time between tracks. When access time between tracks is 6mS at present, (t) is set as 3mS. A distribution circuit 22 forms two pulses such as the pulse and the pulse after (t)sec by one input pulse, and controls so that transportation by one track will be executed by two pulses.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a floppy disk device used as an external storage device for personal computers, '7-tofl:1 processors, and the like.

Conventional configurations and their problems In recent years, as personal computers have become smaller and more portable, floppy disk drives have also become thinner.
\子8'' Ire 1 I<% h 'I W n n
e VM % # W 4 A device with low power consumption is desired. As floppy disk devices become thinner and smaller, a problem arises in that the temperature inside the device increases due to heat generated by the drive source. In particular, a stepping motor is generally used as a drive source for transporting a magnetic head for recording and reproducing information on a magnetic disk, and the heat generated by the stepping motor when it is energized greatly affects the temperature rise.

A conventional floppy disk device will be described below with reference to one drawing.

FIG. 1 is a perspective view of a magnetic head feeding mechanism of a floppy disk device. This mechanism is generally referred to as a steel belt system. Reference numeral 1 is a stepping motor that is the driving source of this mechanism. A pulley 2 is attached to the shaft of the stepping motor 1 by press fitting or the like. 3 is a carriage,
A magnetic head 4 is attached to the carriage 3.

6 is a steel belt wound α around Boo No. 2 and fixed at both ends to the carriage 3 by applying tension. 6 is a magnetic disk. The carriage 3 is held by a shaft (not shown). The rotation angle of the stepping motor is pulley 2.
The magnetic head is directly transmitted to the carriage 3 via the magnetic head, and is used in the magnetic head feeding mechanism of many floppy disk drives as a mechanism with no backlash.

FIG. 2 is an excitation circuit diagram of a conventional stepping motor. 10, 10', 10", 10"' are stepping motor coils φ1. φ2. φ3. At φ4.

This motor has four coils and is called a four-phase stepping motor. Reference numeral 11 denotes a drive power supply necessary to rotate the stepping motor, and DC+12V is generally used. A hold power supply 12 is used when the stepping motor is held at a certain position, and generally DC-5V is used. Reference numeral 13 denotes a distribution circuit that sequentially switches energization to the coils according to the number of steps in one rotation in the rotational direction.

FIG. 3 is a diagram showing the relationship between the conventional input pulse and the energization (excitation) sequence of each coil of the stepping motor. First, before an input pulse is input, a hold power supply (pc+av) is applied to the coils φ1 and φ2. This method of energizing two coils is called a two-phase excitation drive method. Now, assuming that three pulses are input, when the first pulse is input, the drive power is applied to coils φ2 and φ3, and when the second pulse is input, the drive power is applied to coils φ3 and φ4, and then the third pulse is input.
When the pulse is input, coils φ4 and φ1 are energized,
If the fourth pulse is not input within a certain period of time (T) after the third pulse, the drive power source is switched to the hold power source. A distribution circuit switches energization of the coil and switches the power supply.

As described above, in excitation of a conventional stepping motor, when there are two power sources such as a drive power source and a hold power source, the hold power source is used to reduce heat generation of the drive. When a typical floppy disk device is used, less than 10% of the time it is used is spent on the drive power and the remainder is on the hold power. However, the drive seems to be battery powered (KD (6V)
When driven with a single power supply, the problem was that the drive generated a lot of heat because it was driven and held at 5V DC. Note that if you try to obtain the same torque with a stepping motor driven by 12V DC and a motor driven by 5V DC, the same electric power (wattage) is required, and the winding resistance of the motor is changed.

OBJECTS OF THE INVENTION An object of the present invention is to provide a floppy disk drive in which a stepping motor is excited by a single power source and the heat generated by the drive is reduced.

Composition of the Invention The floppy disk device of the present invention uses a stepping motor as a drive source for moving and stopping a magnetic head to a track on a magnetic disk, and performs one track's worth of scanning with two step angles of the stepping motor, and I! with 1/2 phase excitation of the stepping motor. The system is configured so that the phase excitation when moving in the X direction and stopping on the track is one phase, so when the system chipping motor is started, it is two-phase excitation and the maximum torque of the motor is used as the starting torque. During one hold, the heat generated by the motor can be reduced by one-phase excitation.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is an excitation circuit diagram of a stepping motor of a floppy disk device according to an embodiment of the present invention. 20,
20', 20'', 20'' are stepping motor coils φ1. φ2. φ3. φ4 describes an embodiment of a four-phase stepping motor having four coils.O-21 is a power supply, which is the same power supply required to drive and hold the stepping motor. For example, the power source is D(j
By using -1-5V'i, battery drive becomes possible. 2
2 is the distribution circuit.

This is a circuit that sequentially switches energization to the coil according to the number of steps in one rotation in the rotational direction.

FIG. 5 is a diagram showing the relationship between the input pulse and the energization (excitation a) sequence of each coil of the stepping motor in the embodiment of the present invention.

The operation of this embodiment will be explained below. First, before the first coupler is applied, only the coil φ1 is energized and the motor is in a held state.

Yari/+1/7'1 nogunn+1+A for 7kai71shito1
When L 1 HARUS is input, coils φ1 and φ2 are energized.

After a certain period of time, the coil φ1 is not energized, and only the coil φ2 is energized. When the second pulse is input, the coil φ2
Then, after a certain period of time, the coil φ2 is not energized, and only the coil φ3 is energized. Even when the third pulse is input, the energization of the coils is sequentially switched in the same way. This method of sequentially switching between one coil and two coils is called the 1/2-phase excitation force method. In a floppy disk drive, the interval time between input pulses is called the track-to-track access time, and the fixed time for switching the coil between each coupler is approximately half the track-to-track access time. If the access time between tracks is 6ms, t is SMS
Set to . A distribution circuit performs control such that one input pulse forms two pulses, that pulse and a pulse L seconds later, and the two pulses are used to transport one track.

FIG. 6 shows the torque curve s-c' of the stepping motor. The vertical axis is torque, and the horizontal axis is response frequency, showing the pull-out torque and pull-in torque in two-phase excitation drive and the pull-out torque and pull-in torque in one-phase excitation drive at each frequency.

Pullout torque is a continuous characteristic of a stepping motor.
This is called an escape characteristic, and if a motor is rotating in sync with a certain frequency, and the frequency is gradually increased, the motor's rotational speed will increase in sync with that frequency, but beyond a certain frequency. The torque that causes the motor to go out of synchronization is called pull-out torque, and the maximum torque that can start the motor at a certain frequency is called pull-in torque. Father, the torque in two-phase excitation drive is about 2 compared to that in one-phase excitation drive.
It's double. In reality, the torque required to rotate the stepping motor starts with the first human power pulse, so it is understood that the value of the pull-in torque should be determined, and the value of the pull-out torque should be determined after the second human power pulse. Therefore, in the present invention, 1
・2-phase excitation and 2-phase excitation at startup, then 1-phase excitation
By sequentially switching between phase excitation and two-phase excitation to stop on a track, one-phase excitation consumes half the power of two-phase excitation and reduces heat generation. It drives a stepping motor.

Point M in Figure 6 is the point where the pull-in torque for two-phase excitation, which is required during startup, and the pull-out torque for one-phase excitation, which is the lowest torque during feeding (rotation), are the same.

It can be seen that driving the stepping motor with a response frequency of Bpps (77 seconds per pulse) is most efficient.

Effects of the Invention As is clear from the above explanation, one aspect of the present invention is to feed a stepping motor by one track at two step angles.
In addition, the stepping motor drive method uses 1- and 2-phase excitation, and when stopping on a track, 1-phase excitation is used.
By setting the specifications of the stepping motor (winding, size, etc.) rather than the required torque, the 70-cup disk device can be powered by a single power source, which consumes less power, so it can also be powered by a battery, and it generates less heat. An excellent effect can be obtained in that it can be suppressed.

[Brief explanation of drawings]

Figure 1 is a perspective view of the magnetic head feeding mechanism of a floppy disk drive, Figure 2 is a diagram of the excitation and magnetic circuit of a conventional stepping motor, and Figure 3 is a diagram of the relationship between conventional input pulses and the energization sequence of each coil of the stepping motor. , FIG. 4 is an excitation circuit diagram of the stepping motor of the present invention, FIG. 6 is a diagram showing the relationship between input pulses of the present invention and the energization sequence of each coil of the stepping motor, and FIG. 6 is a torque curve diagram of the stepping motor. 1...-Stepping motor 2...Two IJ, 3...Carriage, 4...Magnetic head, 6...Steel belt +10, 1
0', 10", 10#...Stepping motor coil +11...Drive source +12...
・Hold power supply, 13...Distribution circuit, 20.2
0'. 2o", 2d'... Coil of stepping motor. 21... Power supply, 22... Distribution circuit. Name of agent: Patent attorney Toshio Nakao and one other person No. 1
Fig. 2 Fig. 3 Fig. 71 +-zu- Fig. 4 Fig. 5: i-U-4〈- Fig. 6 (jJ-Cm > k Answer Xi Ling 111 (7'/'S>

Claims (1)

[Claims] A stepping motor is used as a drive source for moving and stopping a magnetic head on a track on a magnetic disk, and money is transferred for one track at two step angles of the stepping motor, and the stepping motor is excited at one or two phases. A floppy disk device characterized in that phase excitation is one phase when driving and stopping on one track.