JPS6363980B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device for recording or reproducing information using a magnetic disk such as a floppy disk.

In a disk device that uses a floppy disk, that is, a flexible magnetic disk, for recording or reproducing, a considerably large current flows through a stepping motor for moving the head in the radial direction of the disk, so heat generation becomes a problem. If the feeding mechanism including the motor undergoes significant linear expansion in the radial direction of the disk, the head position will shift, resulting in reading or writing errors. Therefore, when moving the head in the radial direction of the disk, that is, when angularly displacing the stepping motor,
For example, a relatively high voltage of about 12 V is applied to the stepping motor, and after the head has moved to a specified track, that is, after the stepping motor has made a predetermined angular displacement, a relatively low holding voltage (about 12 V) is applied to obtain a static position holding torque. For example, it is possible to apply 4.3 to 5 V). By the way, even during the stationary position holding period, the higher the voltage, the better the holding torque characteristics (θ-T characteristics), but if the voltage is increased,
The effect of reducing power consumption and suppressing heat generation is reduced. For this reason, it is desirable that the holding voltage be set to a voltage that provides the minimum required holding torque. However, if the holding voltage is low, the static position of the head will shift by about 5 to 10 microns due to the impact when loading the head onto the disk. If the head position deviates by about 50 microns in total with other factors, reading errors and the like will occur due to track deviation.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a magnetic head device that can prevent the magnetic head from shifting and reduce power consumption.

To achieve the above object, the present invention includes a disk rotating device for rotating a magnetic disk, a magnetic head that contacts the magnetic disk to perform recording or reproduction, and a magnetic head that rotates the magnetic disk in the radial direction of the magnetic disk. a stepping motor for feeding the magnetic head; a head loading device for bringing the magnetic head into pressure contact with the magnetic disk in a recording or reproducing state; a relatively high voltage is applied to the stepping motor for a period of time, and then a relatively low voltage is applied to the stepping motor to maintain the stationary position, and at the same time when loading of the magnetic head by the head loading device starts. or a motor voltage supply circuit that applies a voltage higher than the lower voltage to the stepping motor for a predetermined period of time from a point in the vicinity thereof.

According to the above invention, since a high voltage is applied to the stepping motor for a certain period of time in response to the loading of the magnetic head, the holding torque characteristics are improved, and the impact during loading of the magnetic head is applied to the stepping motor. No deviation of the resting position occurs.

Next, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, which schematically shows a floppy disk device, 1 is a magnetic disk, 2 is a disk rotation device, 3 is a clamper, and 4 is a first magnetic head that contacts the bottom surface of the disk 1 to perform recording and reproduction. , 5 is a second magnetic head that contacts the top surface of the disk 1 for recording and reproducing, 6 is a carriage that supports the heads 4 and 5 and moves in the radial direction of the disk 1, 7 is a guide rod, 8 9 is a feeding rack, 9 is a pinion that meshes with the rack 8, 10 is a stepping motor for feeding that rotates the pinion 9, 11 is a stepping motor control drive circuit, and 12 is an arm that supports the second magnetic head 5. , 13 is a spring that biases the arm 12 toward the disk 1 (counterclockwise), 14 is a head loading device consisting of a plunger solenoid, and 15 is a controller.

When recording or reproducing with this floppy disk device, the disk rotating device 2
Rotate. Further, with the second magnetic head 5 spaced apart from the disk 1, the stepping motor 10
The carriage 6 and the magnetic heads 4, 5 are moved to a predetermined position by the drive of the head loading device 14, and the second magnetic head 5 is brought into pressure contact with the disk 1 by turning on or off the plunger solenoid of the head loading device 14.
Then, the disk 1 is held between the second magnetic heads 4 and 5 to bring it into a head loading state, and recording or reproduction is started. In addition, the head loading device 14
When the arm 12 is rotated so that the head 5 is separated from the disk 1, the leaf spring 13
The head 5 at the tip of the arm 12 is pressed against the disk 1 by the counterclockwise biasing force of the arm 12 .

The stepping motor 10 and control drive circuit 11 of this floppy disk device are constructed as shown in FIG. That is, the stepping motor 10 has a four-phase configuration in this embodiment,
The first, second, third, and fourth windings φ ₁ , φ ₂ , φ ₃ ,
It has φ ₄ . One end of each of the windings φ ₁ to _{φ 4} is
It is connected to the +5 power supply line 16 via the rectifier diode D ₁ and to the +12 power supply line 17 via the switching transistor Q ₁ . The other ends of the windings φ ₁ to _{φ 4} are connected to respective switch circuits S ₁ , S ₂ , S ₃ , and S ₄ . Each of the switch circuits S ₁ to _{S 4} is a drive circuit including an open collector transistor, and when turned on, the other ends of the windings φ ₁ to _{φ 4} are grounded.

18 is a stepping motor phase control circuit, and a third
In response to the step signal shown in FIG. A and the direction signal indicating the feed direction supplied from the feed direction signal line 20, the switch circuit S ₁ ~ _S4 on/
This is to create a signal for off control.

21 is a head load signal line, to which a leading edge detection circuit 22 is connected. The leading edge detection circuit 22 detects the leading edge of the head load signal and sends this detection signal to the OR gate 23 at the next stage. Since the step signal line 19 is also connected to the OR gate 23, both the step signal and the leading edge detection signal are output. Reference numeral 24 is a retriggerable monostable multivibrator which is triggered by the step signal obtained from the OR gate 23 and the leading edge detection pulse to generate a pulse of, for example, 30 to 50 ms. The output of multivibrator 24 is supplied to the base of transistor _Q1 via inverter 25. Note that a resistor _R1 is connected to the base of the transistor _Q1 , and a resistor _R2 is connected between the emitter and the base.

In Fig. 2, the motor voltage supply circuit 26 shown surrounded by a dotted line is a new part, which applies a high voltage (+12) when a step signal and a head load signal are generated, and which maintains the rest position. Sometimes it is arranged to apply a lower voltage, ie +5 minus the drop of diode _D1 , about 4.3.

FIG. 4 schematically shows the structure of the stepping motor 10 and the relationship between the switch circuits _S1 to _S4 . Winding wires φ ₁ to _{φ 4} are wound around.

Figure 5 shows the on/off states of the first to fourth switch circuits S1 to S4 shown in Figures ₂ and ₄ , and this embodiment uses a 1-2-1 phase excitation system. Therefore, in the first interval t ₀ - _t 1 S ₁ and S ₄ , in the second interval t ₁ - t 2 _{S 1 ,} in the third interval t ₂ - _{t 3} S ₁ and S ₂ ,
S ₂ in the fourth interval t ₃ to _{t 4} and S 2 in the fifth interval t ₄ to _{t 5}
S ₂ and S ₃ , S 3 in the 6th section, S ₃ and S ₃ in the 7th section
S ₄ , S ₄ is turned on in the eighth section. and,
Similar control is performed with t ₀ t ₈ as one cycle.
In the case of reverse rotation, control is performed in the opposite direction to that shown in FIG. Note that the step signals are generated at times t ₀ to t ₈ , respectively.
Based on this step signal, a signal for obtaining the control state shown in FIG. 5 is supplied from the phase control circuit 18 to the switch circuits _S1 to _S4 . Also, in Figure 5, t ₀ ~
Although the sections between t8 and _t8 are displayed at equal intervals, if the stationary position holding time differs in each step, the above-mentioned intervals will naturally differ.

Next, the operation of the apparatus shown in FIGS. 1 and 2 will be explained with reference to FIG. Now, before _t1 , the stepping motor 10 is in a stationary position holding state, so the transistor _Q1 is off, the diode _D1 is on, and the stepping motor 10
one or two windings selected from φ ₁ to _{φ 4} ,
Approximately 4.3 is supplied. When the head load signal shown at t ₁ to _{t 6} in FIG. 3B is generated at time t ₁ , this leading edge is detected by the leading edge detection circuit 22, and the head load signal shown in FIG.
The head load leading edge detection signal shown in is generated, and the OR
A multi-trigger signal shown in FIG. 3D is generated from the gate 23, and multiple outputs of pulse width T are obtained as shown in FIG. 3E. The pulse width T of this multi-output
is determined to be longer than the head loading time, and is also determined to be slightly longer than the time required for the stepping motor 10 to advance a unit step. When the multi-output of Fig. 3E is obtained between t ₁ and _{t 2} , transistor Q ₁ is turned on and the multi-output of Fig. 3 F
The stepping motor 10 is supplied with about 12 as shown in FIG. On the other hand, when a head load signal is generated, the head loading device 14 responds to this by loading the head 5 into the disk 1 as explained in FIG.
Press it against the At this time, because there is a slight mechanical delay, head 5 does not collide with disk 1 before transistor _Q1 is turned on. If the mechanical delay is small, the headload signal may be delayed and supplied to the headloading device. As mentioned above, if a high voltage is supplied to the stepping motor 10 when the head is loaded, the holding torque characteristics are improved, and even if the head 5 collides with the disk 1, the head position will only shift by about 1 to 2 microns.

When the multi-output disappears at time _t2 , the transistor _Q1 is turned off again, and the motor 10 is supplied with a holding voltage of 4.3 and held at a stationary position. Thereafter, if a step signal is generated at time _t3 as shown in FIG. Third
In the example shown in the figure, the next step signal is input at time t ₄ within a period shorter than the pulse width T, so the multivibrator 24 is triggered again, and the multi-output disappears at time t ₅ after period T from t ₄ . . When multiple outputs are obtained during the period _t3 to _t5 , transistor _Q1 is turned on, and a relatively high voltage of about 12 is applied to the motor 10, so that the stepping operation is performed quickly. Then, when the step operation is completed and the motor returns to a stationary state again, the transistor _Q1 is turned off and a low voltage of 4.3 is applied to the motor 10.

In FIG. 3, the headload signal and the step signal are generated more than a period T apart, so multiple outputs can be obtained independently, but if they are close, the monostable multivibrator 24 is of the retriggerable type. Therefore, the multiple outputs are continuous, and the multiple outputs become low level after a period T from the last trigger pulse. Further, in FIG. 3, two step signals are generated within a period T, but in the case of a single step signal, the multi-output becomes low level after a period T from this signal.

As is clear from the above, according to this example,
Since a high voltage is supplied to the motor 10 during head load, the holding torque characteristics are improved.
Misalignment due to head collisions is reduced.

Furthermore, since a low voltage is supplied when the motor 10 is held at a stationary position, it is possible to significantly reduce the power consumption of the motor 10.

Furthermore, since the configuration is such that the step signal and the leading edge detection signal are input as trigger pulses to the common multivibrator 24, it is possible to apply a high voltage with a simple circuit configuration.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto and can be further modified. For example, the motor 10 may be a hybrid stepping motor shown in FIGS. 6 and 7. The rotor 27 of this hybrid stepping motor is composed of a permanent magnet 29 and a laminated steel plate 30, and has an uneven surface. Furthermore, the surface of the pole on which the winding φ of the stator 28 is provided also has irregularities, so that a small step angle can be obtained.

Further, the motor 10 may be a VR (variable reluctance) type stepping motor configured to step-drive by changing the number of poles of the rotor and stator.

Also, instead of the 1-2-1 phase excitation method, the 1-1
A phase excitation method or a 2-2 phase excitation method may be used.
Furthermore, although a double-sided floppy disk device is shown in FIG. 1, this can be changed to a single-sided type, and a pad can be pressed against the disk 1 instead of the second magnetic head 5, thereby creating a head-loaded state. Good too. Further, the feeding method of the reciprocating table 6 may be a method in which a belt or wire is driven by a stepping motor 10, or a method in which a threaded rod is rotated by the motor 10 to provide feeding. Further, the high voltage applied during head loading may be set to a different value from the high voltage applied during stepping. That is, the motor voltage may be switched in three stages. Furthermore, a monostable multivibrator responsive to a step signal and a monostable multivibrator responsive to a headload signal may be provided independently.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a floppy disk device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the motor and control drive circuit of FIG. 1, and FIG.
The figure is a waveform diagram showing the state of points A to F in Figure 2, and
The figure is a cross-sectional view schematically showing a stepping motor.
FIG. 5 is a waveform diagram showing the state of a 1-2-1 phase excitation type switch circuit, FIG. 6 is a sectional view of a hybrid stepping motor, and FIG. 7 is a vertical sectional view of FIG. 6. In addition, in the symbols used in the drawings, 1 is a disk, 2 is a rotating device, 4 and 5 are magnetic heads,
10 is a stepping motor, 11 is a control drive circuit,
14 is a head loading device, 22 is a leading edge detection circuit, 24 is a retriggerable monostable multivibrator, and 26 is a motor voltage supply circuit.

Claims (1)

[Scope of Claims] 1. A disk rotation device for rotating a magnetic disk, a magnetic head that performs recording or reproduction by contacting the magnetic disk, and a step for moving the magnetic head in the radial direction of the magnetic disk. a ping motor; a head loading device for pressing the magnetic head into contact with the magnetic disk in a recording or reproducing state; applying a voltage to the stepping motor;
then applying a relatively low voltage to the stepping motor to maintain the stationary position;
The present invention is characterized by comprising a motor voltage supply circuit that applies a voltage higher than the lower voltage to the stepping motor for a certain period of time from the time when loading of the magnetic head by the head loading device starts or from a time close to this time. Magnetic disk device. 2. The magnetic disk according to claim 1, wherein the high voltage applied for a predetermined period of time from the loading start point or a point in the vicinity thereof is the same voltage as the high voltage applied for a predetermined period of time in response to the step signal. Device. 3 The predetermined time and the certain time are about 30 to
The magnetic disk device according to claim 1 or 2, wherein the magnetic disk drive is 50 ms. 4. The magnetic disk device according to claim 1, 2, or 3, wherein the magnetic disk is a flexible magnetic disk.