JPH04243055A - Spindle motor starting method - Google Patents

Abstract

PURPOSE:To start up a spindle motor under the state of relative movement of a magnetic head and a magnetic disk in a magnetic disk device. CONSTITUTION:The magnetic disk device for writing and reading information under such operations that the magnetic head 104 is moved in the radial direction of the magnetic disk 101 by an actuator 103, while the magnetic disk 101 is rotated by using the spindle motor 102; is equipped with an actuator driving means 111 for driving the actuator 103 prior to starting up the spindle motor 102, a timer 121 for outputting a timing signal S1 showing the timing of anticipation of the movement of the magnetic head 104 by operating the actuator 103 and a motor driving means 131 for starting up the spindle motor 102 in response to the timing signal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor starting system used for rotating a magnetic disk in a magnetic disk drive. The magnetic disk device is
Equipped with multiple magnetic disks as recording media, these magnetic disks are attached to a common shaft and are rotated by a spindle motor, while information is written and read using a magnetic head that moves in the radial direction of the magnetic disk. It is configured to do this.

[0002] For such a magnetic disk device,
There is a demand for increased capacity, and in response to this demand, efforts are being made to increase the capacity of magnetic disk devices by increasing the number of magnetic disks and increasing the recording density on the magnetic disks.

0003

[Prior Art] A magnetic head installed in a magnetic disk device is in contact with the surface of the magnetic disk when the rotation of the magnetic disk is stopped, and is caused by the flow of air on the surface of the magnetic disk as the disk rotates. It is configured to float and maintain a predetermined distance from the magnetic disk surface. The distance between the magnetic head and the magnetic disk surface is becoming narrower as the information recording density on the magnetic disk becomes higher. is required.

For this reason, when the magnetic disk is left in a state where it has stopped rotating, the magnetic head and the surface of the magnetic disk are attracted to each other, and the magnetic disk cannot be rotated even if a normal motor drive current is applied to the spindle motor. There were cases where startup failures occurred. A known method for releasing the adhesion between the magnetic head and the surface of the magnetic disk is the compression method, which removes the adhesion by shifting the magnetic head in the radial direction of the magnetic disk.
It is used in large magnetic disk drives with a medium diameter of 8 inches or more.

As shown in FIG. 7, this compression method uses a swing arm 20 that holds a magnetic head 104.
6, the swing arm 204 is moved in the direction shown by the arrow in FIG. The protrusion 206 is connected to the elastic body 208
The magnetic head 104 is moved by a minute distance while the elastic body 208 is bent.

Conventionally, as shown in FIG. 8A, an actuator drive current is first applied to an actuator (not shown) that drives the swing arm 204, and the position of the magnetic head 104 is controlled by the movement of the swing arm 204. (see Figure 8(b)), release the adsorption, and then
As shown in FIG. 8(c), a motor drive current was applied to the spindle motor to start the spindle motor. In this case, the above-mentioned compressing operation maintains the actuator drive current to the actuator 103 even after the attraction is released, so that the magnetic head 104 remains stationary with the protrusion 206 slightly bending the elastic body 208. ing.

[0007]

[Problems to be Solved by the Invention] However, as the surfaces of magnetic disks and magnetic heads become smoother, the contact area between the magnetic head and the magnetic disk when the magnetic disk is stationary is increasing. Therefore, the coefficient of static friction between the magnetic head 104 and the magnetic disk becomes large.

Therefore, as in the conventional method described above, in order to start the spindle motor when both the magnetic head 104 and the magnetic disk are stationary, static friction between the magnetic head 104 and the magnetic disk surface is required. A large torque is required to overcome the force. However, in small magnetic disk drives, due to power supply voltage limitations, it is difficult to increase the motor drive current or voltage supplied to the spindle motor, which makes it difficult to increase the motor drive current or voltage supplied to the spindle motor. It may not be possible to give. In such a case, rotation of the magnetic disk cannot be started due to insufficient torque of the spindle motor, resulting in a startup failure of the magnetic disk device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a spindle motor starting method for starting a spindle motor when a magnetic head and a magnetic disk are in relative motion.

0010

[Means for Solving the Problems] FIGS. 1 and 2 are block diagrams of the principle of the present invention. According to the first aspect of the invention, at least one magnetic disk 101 is connected to a spindle motor 10.
In a magnetic disk device, a magnetic head 104 is moved in the radial direction of a magnetic disk 101 by an actuator 103 while being rotated using a spindle motor 102 to write and read information at a desired position on the magnetic disk 101. an actuator drive means 11 that drives the actuator 103 by applying an actuator drive current having a predetermined pulse width before starting the actuator 103;
1, a timer 121 that outputs a timing signal indicating the timing at which the magnetic head 104 is expected to be moving due to the operation of the actuator 103, and a timer 121 that starts the spindle motor 102 by applying a motor drive current according to the timing signal. The present invention is characterized in that it includes a motor drive means 131 that performs the following steps.

According to a second aspect of the invention, in the spindle motor starting method according to the first aspect, the spindle motor 102
The actuator drive means 111 is provided with a detection means 141 that monitors the operation of the actuator and outputs a detection signal when a startup failure is detected, and the actuator drive means 111 changes the current value in response to the input of the detection signal, and then adjusts the actuator drive current again. The present invention is characterized in that it has a configuration in which the voltage is applied.

According to the third aspect of the invention, while at least one magnetic disk 101 is rotated using a spindle motor 102, a magnetic head 104 is moved in the radial direction of the magnetic disk 101 by an actuator 103. In a magnetic disk device that writes and reads information at a desired position, a spindle motor 102 is driven by applying a motor drive current having a predetermined current value.
and monitors the operation of the motor drive means 132 that starts the motor and maintains this motor drive current, and the spindle motor 102,
A detection means 141 outputs a detection signal when a starting failure is detected, and an actuator drive means 112 applies an actuator drive current having a predetermined pulse width to drive the actuator 103 in response to the input of the detection signal. It is characterized by having

According to a fourth aspect of the present invention, in the spindle motor starting method according to the third aspect, a timer 121 outputs a timing signal indicating a timing at which the magnetic head 104 is expected to be moved by the operation of the actuator 103; In response to the input of the detection signal, the current value of the motor drive current by the motor drive means 132 is switched to a value smaller than the predetermined current value, and in response to the input of the timing signal, the current value of the motor drive current is switched to the predetermined current value. The present invention is characterized in that it includes a current control means 151 for switching the current value.

[0014] The invention according to claim 5 is the spindle motor starting method according to either claim 1 or claim 4,
The timer 121 is characterized in that it is configured to output the timing signal at a timing when the magnetic head 104 is expected to be moving at the maximum speed.

[0015]

[Operation] The invention of claim 1 provides the actuator drive means 1
11 drives the actuator 103 and the magnetic head 10
4 relative to the magnetic disk 101, and the timer 12
1, a timing signal indicating the timing at which the magnetic head 104 is expected to be in motion is output. Therefore, according to this timing signal, the motor driving means 1
31, when the magnetic head 104 and the magnetic disk 101 are in relative motion, that is, the frictional force between the magnetic head 104 and the magnetic disk 101 is proportional to the dynamic friction coefficient. At times, spindle motor 102 may be activated.

According to the second aspect of the invention, the actuator drive means 11
1 operates, so even if the motor drive means 131 fails to start the spindle motor 102, the actuator drive current can be applied again. As a result, the attraction between the magnetic head 104 and the magnetic disk 101 is reliably eliminated, and the magnetic head 104 and the magnetic disk 101 are
When the magnetic head 1 is moving relative to the magnetic head 1, that is, when the magnetic head 1
When the frictional force between the spindle motor 10 and the magnetic disk 101 is proportional to the dynamic friction coefficient, the spindle motor 10
2 can be started.

According to the third aspect of the invention, once the spindle motor 102 is attempted to start, the actuator drive means 11 is activated in response to a detection signal output from the detection means 141.
2 works. At this time, since the motor drive means 132 holds the motor drive current, the actuator 10
When the magnetic head 104 starts moving due to the operation in step 3, that is, when the friction coefficient between the magnetic head 104 and the magnetic disk 101 changes from a static friction coefficient to a kinetic friction coefficient, the spindle motor 102 is activated by the motor drive current described above. The applied torque overcomes the frictional force and the spindle motor 102 is started.

According to the fourth aspect of the invention, the current control means 151 operates according to the determination result by the determination means 142, and while the actuator drive means 112 is in operation, the current value of the motor drive current applied by the motor drive means 132 is controlled. Since the current value is set to be smaller than the predetermined current value, it can be applied even when there is a limit on the power supply provided in the magnetic disk device. Also, in response to the timing signal from the timer 121,
The motor drive current is returned to its original current value by the current control means 151, and a starting torque is applied to the spindle motor 102.

According to the fifth aspect of the invention, by operating the timer 121, the motor drive current can be applied to the spindle motor 102 at a timing when the magnetic head 104 is expected to be moving at the maximum speed. This results in
The spindle motor 102 can be started when the magnetic head 104 and the magnetic disk 101 are in reliable relative motion.

[0020]

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 3 shows the configuration of an embodiment of a magnetic disk device to which the spindle motor starting method of the present invention is applied. In the figure, in the magnetic disk device, a motor drive circuit 212 and an actuator drive circuit 213 operate according to instructions from a microprocessor (MPU) 211, and drive a DC motor 201 and an actuator 103, respectively. A motor 201 rotates a magnetic disk 101, and an actuator 103 rotates a magnetic head 104 attached to the tip of a swing arm 204.
is configured to move in the radial direction of the magnetic disk 101.

[0021] Furthermore, a sensor 214 is provided to detect the rotation of the DC motor 201 described above, and the MPU 211
controls the rotational operation of the magnetic disk 101 by controlling the motor drive circuit 212 based on the detection result by the sensor 214. In the initial state, the swing arm 204 described above is attached to the magnetic disk 10.
As shown in FIG. 7, the protrusion 206 provided on this swing arm 204 is provided on a stopper 207 for preventing runaway. It is in contact with the elastic body 208 for shock absorption.

[0022] Hereinafter, the DC in this magnetic disk device will be described.
The starting operation of the motor 201 will be explained. In Figure 4, D
A flowchart showing the starting operation of the C motor is shown. First, the MPU
211 instructs the actuator drive circuit 213 to apply a predetermined actuator drive current to start compressing operation (step 401).

In response to this instruction, the actuator drive circuit 213 applies a pulse current of 1 A with a pulse width of 2 ms to the actuator 103 as an actuator drive current, as shown in FIG. 5(a). While this pulse current is being supplied to the actuator 103, the swing arm 204 is driven to the inner side by the actuator 103. Therefore, this swing arm 204
As the protrusion 206 moves, the runaway prevention stopper 2
As shown in FIG. 5(b), the elastic body 208 is bent by the distance
The magnetic head 104 moves toward the inner side by a certain amount. Thereafter, when the above-mentioned pulse current stops, the displacement of the magnetic head 104 toward the inner side reaches its maximum, and from then on, due to the repulsive force of the elastic body 208, the swing arm 20
4 is pushed back toward the outer side, the magnetic head 104 is also displaced toward the outer side (see FIG. 5(b)). However, in FIG. 5(b), the displacement of the magnetic head 104 in the initial state is expressed as 0 displacement, and the displacement toward the inner side is expressed as positive displacement.

During the compressing operation described above, if conditions such as the pulse width and current value of the actuator drive current applied to the actuator 103 are constant, the magnetic head 1
04 is considered to always move in the same way. Therefore, it is possible to estimate the time point at which the magnetic head 104 is most displaced toward the inner side and the outer side from the conditions during the compress operation, and based on this, the magnetic head 104 can be moved relative to the magnetic disk 101. It is possible to estimate the period (indicated by symbols a and b in FIG. 5(b)) during which the current period is expected to continue. Alternatively, this period may be determined in advance based on experiments or the like.

The MPU 211 operates as a timer 121 and waits until a predetermined time τ has elapsed after starting the compressing operation in the actuator drive circuit 213 (step 402). When this occurs, as an affirmative determination in step 402, it is sufficient to instruct the motor drive circuit 212 to start the DC motor 201 (step 403).

For example, if the motor drive circuit 212 is instructed to start 4 ms after starting the application of the actuator drive current, the magnetic head 104 will start as shown in FIGS. 5(b) and 5(c). When the motor is moving at maximum speed at the position of zero displacement, the motor drive current rises and the DC
Normal starting torque is applied to motor 201. Here, the dynamic friction coefficient is generally smaller than the static friction coefficient, so
When the magnetic head 104 and the magnetic disk 101 are in relative motion, the DC motor 201 can be started with a smaller starting torque than when the magnetic head 104 and the magnetic disk 101 are stationary. Therefore, in this case, the normal starting torque applied to the DC motor 201 can overcome the frictional force, so the DC motor 201 starts rotating.

In this manner, when the predetermined time τ has elapsed since the MPU 211 instructs the compressing operation, the MPU 211 instructs the motor drive circuit 212 to start the DC motor 201, thereby causing the magnetic head 104 to move toward the magnetic disk. 101
DC motor 20 is in motion relative to
1, and the DC motor 201 can be started with a relatively small torque. Therefore, since the DC motor 201 can be reliably started with the normal starting torque, starting failures can be prevented and the reliability of the magnetic disk device can be improved.

Furthermore, since it is possible to reliably drive a large number of magnetic disks without increasing the motor drive current supplied to the DC motor 201, even a small magnetic disk device can have a large capacity by increasing the number of magnetic disks. It is possible to aim for In particular, as mentioned above, the magnetic head 1
If the time from which the displacement of the magnetic head 104 becomes 0 and the speed reaches its maximum is the predetermined time τ mentioned above, the period during which the magnetic head 104 moves back and forth is relatively long and continuous, so the DC motor 201 can be reliably activated within the period b shown in FIG. 5(b). Alternatively, the time corresponding to the time point within the period a shown in FIG. 5(b) may be set as the time τ.

By the way, the adhesion state between the surface of the magnetic disk 101 and the magnetic head 104 and the coefficient of friction between them change depending on the surrounding environment, aging, and the time the magnetic head 104 is left in a stationary state. Therefore, by the compressing operation described above, the magnetic head 104 and the magnetic disk 10
In some cases, it may not be possible to release the adsorption with 1. Conversely, depending on the conditions, it may be possible to normally start the DC motor 201 by applying a normal starting torque. Below, in response to the various conditions mentioned above, D
A method for starting the C motor 201 will be explained.

FIG. 6 shows a flowchart representing the starting operation of the DC motor. First, the MPU 211 controls the motor drive circuit 21
2 to start the DC motor 201 (step 601), and in response, the motor drive circuit 212 supplies motor drive current to the DC motor 201, and the DC
Normal starting torque is applied to motor 201.

At this time, the MPU 211 determines whether or not the DC motor 201 has started rotating normally, based on the measurement result notified from the sensor 214 described above (step 602). For example, within a predetermined time, sensor 214
If a detection result indicating that the DC motor 201 has rotated is notified from the controller 1, it may be determined that the DC motor 201 has started rotating normally. In this way, the sensor 21
4 and the MPU 211 realize the function of the detection means 141.

Furthermore, when the MPU 211 determines in step 602 that the DC motor 201 has started rotating normally (affirmative determination), it ends the startup process. On the other hand, in the case of a negative determination in step 602, the MPU 211 causes the motor drive circuit 212 to
Instructs to stop the motor drive current or switch to a current value smaller than the normal motor drive current (step 60).
3), followed by steps 401 to 4 described above.
03, the compressor operation is started (step 604), and the predetermined time τ is waited for (step 605).
), try to start the DC motor again (step 606).
.

When the DC motor 201 starts rotating in this way, the MPU 211 makes an affirmative determination in step 607 in response to the notification from the sensor 214, and ends the startup process. On the other hand, in the case of a negative determination in step 607, the host computer (not shown)
Error processing such as error notification to (step 608)
After doing this, the startup process can be completed.

Furthermore, as an error process, the actuator drive circuit 213 is instructed to perform the compress operation again by changing the conditions such as the current value of the actuator drive current, and then, after waiting for the elapse of the above-mentioned time τ, DC again
Starting the motor 201 may also be attempted. If the adsorption between the magnetic head 104 and the magnetic disk 101 is released and the DC motor 201 is able to start normally, the MPU 211 normally completes the start-up process. The startup process may be abnormally terminated after issuing an error notification.

As described above, first, the normal startup process is attempted, and if the normal startup process fails, the relative movement between the magnetic head 104 and the magnetic disk 101 is started, and the DC motor is started again. By trying to start the engine, if the normal starting torque is sufficient to start the engine,
This can prevent unnecessary processing. Furthermore, if the adhesion between the magnetic disk 101 and the magnetic head 104 cannot be released, changing the conditions and performing the compressing operation again will ensure that the adsorption is released and the relative movement begins. becomes possible.

[0036] In this way, D
It is possible to reliably start the C motor 201, prevent startup failures of the magnetic disk device, and improve reliability. In addition, in step 603, the motor drive current is switched to a value smaller than the normal current value, so there is no need to provide an extra power supply to perform the compressing operation, and the power supply voltage in the small magnetic disk device is reduced. Can perform well within limits.

On the other hand, if there is sufficient power supply voltage, step 603 described above may be omitted and the compressor operation may be started while the motor drive current is maintained. In this case, the relative motion between the magnetic head 104 and the magnetic disk 101 is driven with a normal starting torque applied to the DC motor 201, so that at the start of this movement, the above-mentioned starting torque is applied. can overcome the frictional force between the magnetic head 104 and the surface of the magnetic disk 101 and start the DC motor 201.

[0038]

Effects of the Invention As explained above, the present invention makes it possible to apply a motor drive current while the magnetic head and magnetic disk are in relative motion. By applying a starting torque sufficient to overcome the force, the spindle motor can be started reliably and startup failures of the magnetic disk device can be prevented.
The reliability of the magnetic disk device can be improved.

[Brief explanation of the drawing]

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

FIG. 2 is a block diagram of the principle of the present invention.

FIG. 3 is a configuration diagram of an embodiment of a magnetic disk device to which the spindle motor starting method of the present invention is applied.

FIG. 4 is a flowchart showing the starting operation of the DC motor.

FIG. 5 is a timing chart showing the starting operation of the DC motor.

FIG. 6 is a flowchart showing the starting operation of the DC motor.

FIG. 7 is an explanatory diagram of a compress method.

FIG. 8 is an explanatory diagram of a compress method.

[Explanation of symbols]

101 Magnetic disk 102 Spindle motor 103 Actuator 104 Magnetic head 111 Actuator drive means 112 Actuator drive means 121 Timer 131 Motor drive means 132 Motor drive means 141 Detection means 151 Current control means 201 DC motor 204 Swing arm 206 Projection 207 Runaway prevention stopper 208 Elastic body 211 Microprocessor (MPU) 212 Motor drive circuit 213 Actuator drive circuit 214 Sensor

Claims (5)

[Claims] Claim 1: At least one magnetic disk (10
1) using the spindle motor (102), the magnetic head (1) is rotated by the actuator (103).
104) in the radial direction of the magnetic disk (101) to write and read information at a desired position on the magnetic disk (101). prior to,
an actuator drive means (111) for driving the actuator (103) by applying an actuator drive current having a predetermined pulse width;
a timer (121) that outputs a timing signal indicating the timing at which the magnetic head (104) is expected to be moving due to the operation of the magnetic head (103); Motor drive means (131) for starting the motor (102)
) A spindle motor starting method characterized by the following. 2. The spindle motor starting method according to claim 1, further comprising a detection means (141) for monitoring the operation of the spindle motor (102) and outputting a detection signal when a starting failure is detected, A spindle motor starting method characterized in that the driving means (111) changes the current value in response to the input of the detection signal and applies the actuator driving current again. Claim 3: At least one magnetic disk (10
1) using the spindle motor (102), the magnetic head (1) is rotated by the actuator (103).
104) in a magnetic disk device that moves a magnetic disk (104) in the radial direction of the magnetic disk (101) and writes and reads information at a desired position on the magnetic disk (101). A motor driving means (132) that applies a current to start the spindle motor (102) and maintains this motor drive current, and monitors the operation of the spindle motor (102) and generates a detection signal when a starting failure is detected. and an actuator drive means (11) that applies an actuator drive current having a predetermined pulse width to drive the actuator (103) in response to the input of the detection signal.
2) A spindle motor starting method characterized by comprising: 4. In the spindle motor starting method according to claim 3, the magnetic head (104) is expected to operate in response to the application of the actuator drive current, and to move the magnetic head (104) by the operation of the actuator (103). a timer (121) that outputs a timing signal indicating the timing at which the motor is driven, and a current value of the motor drive current by the motor drive means (132) that is switched to a value smaller than the predetermined current value in response to the input of the detection signal. A spindle motor starting method characterized by further comprising: current control means (151) for switching the current value of the motor drive current to the predetermined current value in accordance with the input of the timing signal. 5. In the spindle motor starting method according to claim 1 or claim 4, the timer (1
21) A spindle motor starting method characterized in that the timing signal is output at a timing when the magnetic head (104) is expected to be moving at maximum speed.