JPH09320175A - Impact-detecting mechanism for magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect impact which may cause off-track and destruction of data, at the time of R/W in a magnetic disk device. SOLUTION: The spindle motor system of the magnetic disk device 1 is provided with a rotational speed measuring device 6 which directly detects the speed variation of the rotational section of the spindle motor 3 in the tangential direction. The measurement of speed variation in the angular speed can be substituted for the rotational speed measuring device 6. Thus, the measuring device 6 detects the impact applied to the disk device 1 by the rotational speed variation of the spindle motor 3, and when the device 1 undergoes an impact, the measuring device 6 issues a R/W inhibiting command to the R/W controlling IC 8 on the PKG 7, to inhibit the R/W action of the magnetic disk device 1, thereby preventing the destruction of the data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock detecting mechanism for a magnetic disk device, and more particularly to a shock detecting mechanism for preventing data destruction due to a shock from the outside when recording / reproducing magnetic information (data). Regarding

[0002]

2. Description of the Related Art Conventionally, in a magnetic disk device, as a mechanism for detecting an impact applied to the device, an impact detection element (for example, a piezoelectric element and a weight, which is installed on a device base or a control circuit of the device, is used). It is common to use a combination of them) and directly detect the impact applied to the magnetic disk device.

As another conventional example, an abnormal current detector for detecting a drive current of a spindle motor is provided in a magnetic disk device, and an abnormality of the magnetic disk device is detected from an abnormal change in the drive current during steady rotation of the spindle motor. However, it is disclosed that the magnetic recording medium and the magnetic head are prevented from being damaged by stopping the magnetic disk device promptly (for example, JP-A-3-91161).
Issue).

[0004]

In recording / reproducing (hereinafter referred to as R / W) magnetic information in a magnetic disk device, a magnetic head is generally constructed for an arbitrary recording track on a rotating magnetic recording medium. This is performed by moving the electromagnetic conversion part that is floating on the air bearing surface of the slider that is a member. The width of the recording track in this case is approximately 10 μm or less, and this track width tends to become narrower year by year as the recording density becomes higher.

Further, the most general positioner used as a moving and positioning mechanism for a magnetic head is composed of an oscillating voice coil motor, but it is extremely sensitive to external force such as impact, A position shift called off-track easily occurs from an arbitrary recording track. Further, if R / W is performed in a state where off-track has occurred, data error may occur, and particularly off-track at the time of recording has a risk of data destruction.

Further, in the case of the conventional example disclosed in Japanese Patent Laid-Open No. 3-91161, since the abnormal current detector is provided, the manufacturing cost of the magnetic disk device becomes expensive.

An object of the present invention is to provide a shock detecting mechanism for detecting a shock that causes off-track in a magnetic disk device and preventing data destruction during R / W.

[0008]

SUMMARY OF THE INVENTION The present invention is a shock detecting mechanism for a magnetic disk device, wherein the rotating system of the spindle motor is provided with a detecting means for detecting tangential speed fluctuations of the rotating portion of the spindle motor. Is characterized by. Further, the tangential speed fluctuation may be an angular speed fluctuation. Further, it is characterized in that the fluctuation amount of the rotation speed of the spindle motor due to the impact of the magnetic disk device is detected by the fluctuation of the pulse interval of the servo pattern.

Thus, the shock applied to the magnetic disk device is detected from the fluctuation of the rotation speed of the spindle motor, and when the shock is received, a warning is issued to the R / W system circuit, and the R / W system is warned.
The operation can be stopped and the destruction of recorded data can be prevented.

[0010]

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

FIG. 1 is a top view showing an embodiment of the present invention. Further, FIG. 2 is a flow chart showing a flow of operation of the impact detection mechanism of the present invention.

Referring to FIG. 1, the present invention relates to a magnetic disk device 1 and a package which is an electronic circuit for control (hereinafter referred to as P
A magnetic disk device 1 includes a magnetic recording medium 2 for storing data and a spindle motor (SPM) for rotating the magnetic recording medium 2. 3, a magnetic head 5 for recording / reproducing data on / from the magnetic recording medium 2,
A positioner 4 using an oscillating voice coil motor (VCM) for positioning the magnetic head 5 and a rotation speed measuring device 6 for measuring the rotation speed of the spindle motor 3 in real time are provided.

Next, referring to the flow chart shown in FIG. 2, the shock detecting mechanism of the magnetic disk drive of the present invention is as follows.
First, the rotation of the spindle motor 3 is started up, the magnetic disk device 1 is set in the ready state, and then the R / W operation is performed. At this time, the rotation speed measuring device 6 measures the fluctuation of the rotation speed of the spindle motor 3 in real time.

Here, in the case of the magnetic disk device using the oscillating type positioner 4 as in the present embodiment, the weight alone around the rotation axis is balanced by the positioner alone, so that the magnetic disk device is The off-track is not likely to occur even if the shock does not include a linear rotation component. However, on the contrary, in the case of a shock including a rotational component, as a characteristic of a positioner system using a swing type voice coil motor, it is very sensitive to the shock and off-track is likely to occur. That is, when an impact including this rotation component is applied to the magnetic disk device 1 from the outside, the rotation speed of the spindle motor 3, which is a rotating body, fluctuates at the same time.

Therefore, the rotational speed measuring device 6 continuously determines the rotational speed fluctuation of the spindle motor 3 to determine whether or not an external shock such as off-track is applied to the magnetic disk device 1. Before a fatal off-track is generated when a shock is received, an R / W prohibition command is issued to the R / W control IC 8 on the PKG 7,
The operation of the magnetic disk device 1 is stopped to prevent the data from being destroyed.

Next, another embodiment of the present invention will be described.

FIG. 3 is a sectional view showing another embodiment of the present invention. Referring to FIG. 3, the basic configuration of the present invention is as follows.
1 is the same as the embodiment of FIG. 1, but the embodiment of FIG. 3 is different from the embodiment of FIG. 1 in that the embodiment of FIG. 1 determines the rotation speed of the spindle motor 3 in the rotation tangential direction of the magnetic recording medium. In contrast to the above, the embodiment of FIG. 3 has an angular velocity measuring device 9 for detecting the rotational angular velocity.

In this embodiment, the angular velocity measuring device 9 for detecting the angular velocity of the magnetic disk device 1 is provided near the outside of the spindle motor 3, but the angular velocity measuring device 9 is built in the spindle motor 3. It may be mounted in the form.
Here, the angular velocity data measured by the angular velocity measuring device 9 are processed in the same manner as in the embodiment of FIG. 1, and the operation flow is the same as the flowchart shown in FIG.

FIG. 4 is a top view showing still another embodiment of the present invention.

Referring to FIG. 4, the basic structure of the present invention is similar to that of the embodiment of FIG. However, this embodiment does not have a dedicated measuring device for measuring the rotation speed of the spindle motor 3. In this embodiment, the rotation speed of the spindle motor 3 can be detected by reading the servo pattern 10 previously recorded for servo control on the rotating magnetic recording medium 2.

The servo pattern 10 is written on the magnetic recording medium 2 at a constant time interval and pattern for positioning servo control, and the magnetic head 5 for magnetic recording reads the servo pattern 10 to perform positioning. Controlled. That is, the servo pattern 10 is
Because of the characteristic, writing is always performed at a constant interval. Therefore, if the time interval of the servo pattern 10 is measured during servo control, the rotational speed of the spindle motor 3 will change from the time variation of the interval of the servo pattern 10. Can be detected.

Here, the difference between this embodiment and the conventional example is that
This is to measure the rotation speed fluctuation of the spindle motor 3 in real time by adding a function of constantly measuring the server pattern interval to the function of the conventionally mounted R / W control IC 8. As a result, when the rotational speed of the spindle motor 3 fluctuates due to an external impact or the like, the R / W operation can be stopped immediately to prevent the data from being destroyed.

In this embodiment, it is not necessary to prepare a dedicated member for measuring the time interval of the servo patterns 10 which is indispensable for the magnetic disk device 1. For example, a member for measuring the time interval of the servo pattern 10 is P
It is also possible to use an IC used for other purposes on the KG7, and the manufacturing cost of the magnetic disk device does not become expensive. Moreover, the flow of the processing operation is similar to that of the flowchart of FIG.

[0024]

According to the shock detecting mechanism of the magnetic disk device of the present invention, even if a shock such as an off-track is applied when the magnetic disk device is operated, the shock is detected from the fluctuation of the rotation speed of the spindle motor. And stop the R / W operation before causing a fatal off-track,
This has the effect of preventing data destruction in advance.

[Brief description of drawings]

FIG. 1 is a top view showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a basic operation flow of the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a top view showing still another embodiment of the present invention.

[Explanation of symbols]

 1 Magnetic Disk Unit 2 Magnetic Recording Medium 3 Spindle Motor 4 Positioner 5 Magnetic Head 6 Rotation Speed Measuring Device 7 PKG 8 R / W Control IC 9 Angular Velocity Measuring Device 10 Servo Pattern

Claims (3)

[Claims] 1. A shock detecting mechanism for a magnetic disk device, wherein a rotating system of the spindle motor is provided with a detecting means for detecting speed fluctuation in a tangential direction of a rotating portion of the spindle motor. Impact detection mechanism. 2. The shock detection mechanism for a magnetic disk drive according to claim 1, wherein the tangential velocity fluctuation is an angular velocity fluctuation. 3. A shock detecting mechanism for a magnetic disk device, wherein a fluctuation amount of a rotation speed of a spindle motor due to a shock of the magnetic disk device is detected by a fluctuation of a pulse interval of a servo pattern.