JP2546115B2 - Disk device and disk startup method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device and a disk starting method thereof, and more particularly to a disk device which drives a magnetic disk medium by a stepping motor and a disk starting method thereof.

[0002]

2. Description of the Related Art In a disk device such as an FDD (floppy disk drive) device, a floppy disk (hereinafter referred to as a disk or a magnetic disk medium) has been conventionally driven to rotate by using a DC motor. It is common to control the disk at a predetermined rotation speed by performing a closed loop control of the DC motor by the FG servo system.

FIG. 6 is a block diagram of an example of a conventional FDD device to which the closed loop control by the FG servo system is applied.

In the figure, reference numeral 6 denotes a control circuit including a CPU (Central Processing Unit; Central Processing Unit), which is supplied from an external control device (for example, a host computer) connected through an interface circuit 5. The signal processing system and the drive system of the entire FDD device are controlled based on the control signal.

Reference numeral 11 denotes a spindle motor which is a DC motor for driving a disk, and is provided with an FG (Frequeycy Generator) 12 for generating an FG signal having a frequency corresponding to its rotation speed. The spindle motor 11 responds to the control signal from the control circuit 6 by the spindle motor drive control circuit 1
0 performs closed loop control based on the FG signal, and drives the rotation shaft 4 on which the floppy disk 1 is chucked at a predetermined rotation speed.

The stepping motor 9 has a control circuit 6
The stepping motor drive control circuit 8 controls the head carriage 2 having the magnetic head 3 at the tip thereof to move to a predetermined position in the radial direction of the disk 1 in accordance with a control signal from The signal processing circuit 7 connected to the magnetic head 3 performs predetermined signal processing on the reproduced signal from the magnetic head 3 and also performs predetermined signal processing on the recording signal from the control circuit 6 at the time of recording to the magnetic head 3. Supply.

However, in order to perform the closed loop control as described above, the FG 12 is required as shown in the figure, and the spindle motor drive control circuit 10 requires a servo amplifier, which has a drawback that the circuit is complicated and the apparatus becomes expensive. .

Therefore, the FG 12 is omitted by using a stepping motor instead of the spindle motor 11,
Open-loop control of the rotation speed of the rotating shaft 4 has been performed.

In a stepping motor, generally, a rotor formed by a permanent magnet is arranged between a plurality of pairs of iron cores facing each other, and these iron cores are excited by a rectangular wave current to generate a rotating magnetic field. Can be rotated by. Therefore, as is well known, the rotation speed and the rotation angle are precisely controlled by the timing of the exciting current, and the rotation detection mechanism is not required.

In a conventional disk device having a structure in which a magnetic disk medium is driven by a stepping motor, when a control signal for instructing disk startup is sent from the control circuit, the stepping motor rotates at a constant speed at a predetermined rotation speed. The disk is started by the method of driving the stepping motor by generating an exciting current at a constant timing so that the disk can be driven with a predetermined rotation torque.

[0011]

However, according to the above-described conventional disk device and its disk starting method, when the stiction occurs when the disk is left in the device for a long time and stiction occurs, There was a problem that the disk could not be started due to lack. Here, the stiction means that, when the magnetic head is in contact with the disk, for example, the magnetic head and the disk adhere to each other, and the magnetic head and the disk should be movable when the disk is started. It means that the dynamic friction increases and the start of the disk is hindered.

It is an object of the present invention to provide a disk device and a disk starting method thereof that can start a disk even if stiction occurs.

[0013]

The above problems can be solved by constructing according to the principle diagram of FIG.

That is, the stepping motor 14 for rotationally driving the disk-shaped magnetic recording medium 1, the driving means 27 for driving the stepping motor 14 based on the speed control signal Cv, and the driving means 27 for generating the speed control signal Cv.
And a start control means 6 for generating a motor start signal Sm and sending it to the speed control means 21. When the start control means 6 sends the motor start signal Sm, the speed control means 21 is provided. In the disk device that controls the rotation of the stepping motor 14 at a speed corresponding to the timing of the speed control signal Cv generated by the speed control signal 21, the speed control means 21 causes the stepping motor 14 to move to a predetermined time after the motor start signal Sm is sent. Timing of the speed control signal Cv so that the magnetic recording medium 1 is driven at a constant speed at a predetermined speed and a predetermined rotation torque, and at the time of startup, the magnetic recording medium 1 is driven and started at a rotation torque larger than the predetermined rotation torque. This is solved by adopting a configuration in which is changed stepwise .

[0015]

According to the present invention having the above structure, the speed control means 21
When the motor start signal Sm is received, a control signal for driving the magnetic recording medium 1 with a predetermined start torque to start it is generated to control the drive means 27, and after the motor start signal Sm is received, a predetermined signal is received. After a lapse of time, it operates to control the drive means 27 by generating a control signal for driving the magnetic recording medium 1 at a constant speed with a predetermined rotational torque smaller than a predetermined speed and a predetermined starting torque.

[0016]

FIG. 2 is a block diagram of an embodiment of the present invention. In the figure, the same components as in FIG.
The description is omitted.

In FIG. 2, a stepping motor 14 is used in place of the spindle motor 11 shown in FIG. 6, and the stepping motor 14 is driven and controlled by an exciting current I _EX from the stepping motor drive control circuit 13 to control the rotation speed of the rotary shaft 4. It shows an FDD device (disk device) configured to perform open loop control. According to this configuration, an FG (Frequeycy Generate) is shown.
It is possible to omit r) and have a simple circuit configuration.

In FIG. 2, reference numeral 6 denotes the above-mentioned start-up control means, which is the above-mentioned control circuit including a microcomputer. Reference numeral 13 denotes a stepping motor drive control circuit 13 including the speed control means 21 and the drive means 27 described above. The stepping motor drive control circuit 13 receives the motor start signal S from the control circuit 6.
Upon receiving m, the exciting current I _EX is supplied to the stepping motor 14 to control the rotation of the stepping motor 14.

Next, FIG. 3 is a block diagram of an essential part of the stepping motor drive control circuit 13 in FIG.

In FIG. 3, reference numeral 27 is a drive circuit which is the above-mentioned drive means. The drive circuit 27 is driven by supplying a drive current _ID to a power supply terminal DR connected to a power supply V _CC through a resistor R, and outputs a motor start signal Sm from an unillustrated control circuit to an ON input terminal ON. Is being supplied.

The monostable multivibrator 22, the OR circuit 24, the timing generation circuit 25, and the shift register 26 constitute the above speed control means (21), and the monostable multivibrator 22 has A trigger input and timing generation. The motor start signal Sm is supplied to the ON input terminal ON of the circuit 25 from the control circuit not shown in FIG.

When the motor start signal Sm is set to the high level, the shift register 26 of the speed control means (21) outputs a four-phase excitation signal (speed control signal) Cv to the drive circuit 27 to drive it as described below. The circuit 27 outputs the exciting current I _EX based on the timing of the exciting signal Cv to the stepping motor which does not appear in FIG.

That is, when the motor start signal Sm from the control circuit becomes high level and is sent to each of the above circuits (start signal sending step), the timing generation circuit 25 and the drive circuit 27 are turned on, and The stable multivibrator 22 is triggered and outputs a positive pulse signal a to the OR circuit 24.

Although one input of the OR circuit 24 is grounded, the output signal b of the OR circuit 24 is the motor start signal S.
The pulse signal is the same as the pulse signal a, which rises in synchronization with the rise of m and then falls in synchronization with the fall of the pulse signal a after a predetermined time.

This output signal b is output to the timing generation circuit 25.
Is supplied to the slow-up trigger terminal STR, and the timing generation circuit 25 is triggered by the rising edge of the output signal b (almost at the same time as the rising edge of the motor starting signal Sm) to start outputting the output pulse train c.

FIG. 4 is a diagram for explaining the operation of the timing generation circuit 25 of FIG. 3. In FIG. 4, the rectangular wave I shows the waveform of the output pulse train c, and the curve II shows the change of its frequency.
The horizontal axis represents time, the vertical axis represents the amplitude of the rectangular wave I, that is, the low level (L) or the high level (L) and the frequency F of the curve II.
Represents The curve III is the rotational torque T _R described later.

At time t ₀ in FIG. 4, the motor start signal S
If m rises and the output signal b to the slow-up trigger terminal STR of the timing generation circuit 25 rises almost at the same time, the first pulse of the output pulse train c is delayed by a predetermined time ΔT due to the propagation delay time of the timing generation circuit 25. Stands up. Thereafter, until time t _1, the output pulse train c (rectangular wave I) is output with the constant frequency F ₁ and the pulse period kept constant.

From the subsequent time t _{1 to} time t ₂ , the pulse cycle is gradually shortened, and the frequency of the output pulse train c gradually increases from F ₁ to F ₂ as shown in the figure. After time t _{2 when the} frequency becomes F ₂ (> F ₁ ), the frequency F ₂ of the output pulse train c is kept constant and the pulse period is kept constant.

The output pulse train c thus generated by being triggered by the rising edge of the output signal b is the shift register 2
4 phase excitation signals C, which are input to the clock input terminals CK of 6 and have a predetermined pulse width and a predetermined phase shift
v is generated and output.

By the way, FIG. 5 shows a rotation torque characteristic of a general stepping motor. In the figure, the horizontal axis the frequency F of the excitation signal Cv, and the vertical axis represents the rotational torque T _R. As shown in the figure, the rotation torque T _R of the stepping motor is approximately logarithmically inversely proportional to the frequency F of the excitation signal Cv (that is, the excitation current I _EX ).

On the other hand, the frequency of the excitation signal Cv is F
The rotational torque T ₁ as shown in FIG. 5 when the _1, when the F ₂ and is configured to generate a rotational torque T _2, the frequency F ₂ is (referred to as appropriate disk or magnetic disk medium) floppy disk Is set to a value at which the disk rotates at a constant speed during steady rotation, and the rotation torque T ₂ is set to a value at which the disk is driven to rotate at a predetermined rotation torque during steady rotation.

Further, the frequency F ₁ is set to a value at which the disk is rotated at a constant speed slower than the above predetermined speed, and the rotation torque T ₁ is set to a value larger than the above predetermined rotation torque T ₂ . . The value of the rotational torque T ₁ is set to a value large enough to start the disk even if the disk causes stiction with respect to the magnetic head and the dynamic friction between the two increases.

[0033] That is, if indicated by the rotational torque T dashed line the outline of changes in _R III in FIG. 4, the time t ₀ to time t ₁ is constant rotational torque T _1, the time t ₂ after a constant rotational torque T ₂ , and the time t _{1 to the} time t ₂ gradually decreases as the frequency F of the excitation signal Cv increases.

In this embodiment, the motor starting step is from time t _{0 to} time t _{2 and the} constant speed driving step is from time t ₂ onward, but the constant torque period from time t _{0 to} time t ₁ is omitted. It is also conceivable to set the time t _{1 to the} time t ₂ as the motor starting process.

As described above, according to this embodiment, when the motor starting signal Sm is sent to the speed control means (21) including the timing generation circuit 25 and the like at the high level, the timing generation circuit 25 is sent. Generates a pulse train c that serves as a reference for the timing of the four-phase excitation signal Cv output from the shift register 26 by gradually shortening the pulse period. The pulse cycle of the pulse train c gradually becomes shorter.
By doing so, the excitation signal Cv is changed stepwise,
The rotation torque T _R of the ping motor 14 also becomes smaller stepwise.
4 (continuously shown in FIG. 4, but more accurately
It is smaller on the floor). As a result, the drive circuit 27 can drive the disk with sufficient starting torque even if stiction occurs.

Furthermore, since the slow-up control for gradually accelerating the rotation speed is performed from the start signal Sm being at the high level to the time t ₂ after a predetermined time, the stepping motor causes a step-out phenomenon. There are advantages that the rotation cannot be controlled and the rotation is not stopped before reaching the constant speed rotation. Incidentally, the time t ₂ after the disc is rotated at a predetermined rotational speed and a predetermined rotational torque.

Although the FDD device has been described in the above embodiments, the present invention can be applied to any disk device that drives a magnetic disk medium by a stepping motor, and may be, for example, a hard disk device.

[0038]

As described above, according to the present invention, the speed control means controls the magnetic recording medium to start by driving the magnetic recording medium with a predetermined starting torque when the motor start signal is received from the starting control means. Later speed control signal timing
The magnetic recording medium is controlled so as to be driven at a constant speed at a predetermined speed and a predetermined rotational torque smaller than the predetermined starting torque by changing the above stepwise. Ru good to start-up torque
Low cost due to stepwise change of drive and rotation torque
It has the feature that the motor can start the magnetic recording medium reliably .

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram of an embodiment of the present invention.

FIG. 3 is a block diagram of a main part of one embodiment of the present invention.

FIG. 4 is an operation explanatory diagram of the embodiment of the present invention.

FIG. 5 is a diagram showing an example of a rotation torque characteristic of a stepping motor.

FIG. 6 is a block diagram of an example of a conventional disk device.

[Explanation of symbols]

 1 Floppy Disk (Disk, Magnetic Recording Medium) 6 Control Circuit (Startup Control Means) 14 Stepping Motor 21 Speed Control Means 25 Timing Generation Circuit 26 Shift Register 27 Drive Circuit (Drive Means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A 1-205758 (JP, A) JP-A 1-255494 (JP, A) JP-A 1-222699 (JP, A)

Claims (2)

(57) [Claims] 1. A stepping motor that rotationally drives a disk-shaped magnetic recording medium, a driving unit that drives the stepping motor based on a speed control signal, and a speed that generates the speed control signal and controls the driving unit. And a start-up control unit for generating a motor start-up signal and sending it to the speed control unit. When the start-up control unit sends the motor start-up signal,
In a disk device that controls the rotation of the stepping motor at a speed according to the timing of the speed control signal generated by the speed control means, the speed control means is configured to perform the stepping after a predetermined time after the motor start signal is sent. A motor drives the magnetic recording medium at a constant speed at a predetermined speed and a predetermined rotation torque,
Further, at the time of start-up, the timing of the speed control signal is changed stepwise so as to drive and start the magnetic recording medium with a rotation torque larger than the predetermined rotation torque. 2. A stepping motor that rotationally drives a disk-shaped magnetic recording medium, a driving unit that drives the stepping motor based on a speed control signal, and a speed that generates the speed control signal and controls the driving unit. And a start-up control unit for generating a motor start-up signal and sending it to the speed control unit. When the start-up control unit sends the motor start-up signal,
A disk starting method for a disk device for controlling rotation of the stepping motor at a speed according to the timing of the speed control signal generated by the speed control means, wherein the starting control means sends a motor starting signal to the speed control means. an activation signal transmitting step of, in response to the motor startup signal, the magnetic recording medium and start to drive at a predetermined starting torque, the magnetic recording medium is a predetermined
The timing can be changed stepwise until the speed reaches
A motor starting step for generating the control signal to control the driving means, and a predetermined time after the motor starting signal is sent, the magnetic magnetic recording medium is moved at a predetermined speed and a predetermined speed in accordance with the motor starting signal. A constant speed driving step of controlling the driving means by generating the control signal so as to perform constant speed driving with a predetermined rotational torque smaller than the predetermined starting torque. .