JPH05120859A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent the generation of a thermal off track by predicting a temperature change from the quantity of the changes of a temperature in an HDA and of a VCM current and making the temperature of the HDA constant changing the blowing quantity of a fan. CONSTITUTION:This device is provided with a voice coil motor(VCM) current calculating circuit 104 for calculating VCM current necessary for driving for the positioning of a head disk assembly(HDA) 100 by inputting a difference signal 303. Also, a temperature signal 300 is inputted and a temperature is calculated by a temperature calculating circuit 102. Then, a VCM current change signal 304 and a temperature change signal 305 are stored in a memory 105. Fan rotation number information is taken from the signals 304 and 305 and a memory 106 by a micro processor unit 107, a fan rotation signal 306 is outputted and a temperature in the HDA 100 is maintained at a constant value by a fan control circuit 108. Thus, the generation of the thermal off-track is prevented and data is surely read out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device having a function of cooling a head disk assembly (HDA).

[0002]

2. Description of the Related Art A conventional magnetic disk device is a thermal off-track in which a head for reading data is displaced from a target position due to thermal expansion of an arm supporting a head in the HDA due to temperature rise or temperature change in the HDA. This causes a phenomenon called, which makes it impossible to read data.

[0003]

In the above-mentioned conventional magnetic disk device, it is impossible to predict the temperature change in the HDA. Therefore, it is impossible to prevent the thermal off-track by the predictive control by detecting the temperature change. There were challenges.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a magnetic disk drive capable of predicting a temperature change and suppressing the occurrence of thermal off-track.

[0005]

SUMMARY OF THE INVENTION A magnetic disk device according to the present invention comprises: a change amount of temperature in a head disk assembly;
The temperature change in the head disk assembly is predicted based on the amount of change in the current of the head disk assembly positioning drive motor VCM calculated by the positional difference between the current cylinder currently in use and the target cylinder for the next operation, and the head disk assembly cooling The head disk assembly is provided with means for maintaining a constant temperature so as to eliminate the thermal off-track by changing the amount of air blown by the fan.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In the embodiment shown in FIG. 1, an HDA (head disk assembly) 100, a temperature sensor 101 installed inside the HDA 100, and a temperature change signal 305 output from the temperature sensor 101, a temperature change signal 305 is stored in a memory 10.
5, a temperature calculation circuit 102 for storing temperature change information in a temperature information group 200 in 5 and a target cylinder address signal 30 input via an I / O port 110.
1 and a current cylinder address signal 302 input via the I / O port 111, calculates a cylinder difference expressing the difference between the positions of both cylinders, and outputs a difference signal 303. 103, a VCM (voice coil motor) current, and a VCM current calculation circuit 104 that stores the VCM change current signal 304 in the VCM current change information group 201 in the memory 105, the memory 105, and fan rotation speed information. The memory 106 for storing and the fan rotation signal 306 output by the microprocessor unit 107
The fan control circuit 10 that outputs the fan drive signal 307 for keeping the temperature inside the HDA 100 constant to the fan 109
8 and a fan 109.

Next, the operation of this embodiment will be described with reference to FIG.

FIG. 2 is a fan rotation signal change characteristic diagram due to a temperature change in the HDA and a VCM current change. The position indicated by 0 in FIG. 2 indicates the reference state.

First, the cylinder difference calculation circuit 1
Reference numeral 03 denotes the current cylinder address signal 302 as the position information of the working cylinder input via the I / O port 111 at regular intervals, and the position information of the next operating cylinder input via the I / O port 110. Based on the target cylinder address signal 301, the cylinder difference indicating the position difference between the two cylinders is calculated and output as a difference signal 303.

The VCM current calculation circuit 104 calculates the VCM current required for the positioning drive of the HDA 100 by the input of the difference signal 303, and the VCM calculated previously is calculated.
The difference from the current is used as the VCM current change signal 304 in the memory 1
It is stored in the VCM current change information group 201 in 05 as VCM current change information.

Temperature sensor 101 in HDA 100
Constantly outputs the temperature signal 300.

The temperature calculation circuit 102 inputs the temperature signal 300 at regular time intervals to calculate the temperature, and the difference from the previously calculated temperature is used as the temperature change signal 305, which is the temperature change information group 200 in the memory 105. The temperature change information is stored in.

The microprocessor unit 107 includes a temperature change information group 200 stored in the memory 105 at regular time intervals.
2 and the VCM current change information stored in the VCM change current information group 201 stored in the memory 105, the temperature change information and the VC shown in FIG.
The fan rotation speed information for keeping the temperature in the HDA 100 constant corresponding to the M change current information is fetched from the fan rotation speed information group 106 stored in the memory 106 and output as a fan rotation signal 306.

The fan control circuit 108 outputs a fan drive signal 307 corresponding to the fan rotation signal 306.

The fan 109 is driven at a rotation speed corresponding to the fan drive signal 307, and thus the temperature inside the HDA 100 is maintained at a desired constant value.

[0018]

As described above, according to the present invention, the temperature change is predicted from the change amount of the temperature in the HDA and the change amount of the VCM current necessary for driving the head, and the air flow rate of the fan is changed.
By keeping the temperature of DA constant, there is an effect that thermal off-track can be prevented and data can be surely read.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a temperature change in the HDA, a current change of a head positioning drive VCM, and a fan rotation speed.

[Explanation of reference numerals] 100 HDA 101 Temperature sensor 102 Temperature calculation circuit 103 Cylinder difference calculation circuit 104 VCM current calculation circuit 105 Memory 106 Memory 107 Microprocessor unit 108 Fan control circuit 109 Fan 200 Temperature change information group 201 VCM current change information group 202 Fan rotation speed information group 300 Temperature signal 301 Target cylinder address signal 302 Current cylinder address signal 303 Difference signal 304 VCM current change signal 305 Temperature change signal 306 Fan rotation signal 307 Fan drive signal

Claims (1)

[Claims] 1. A head based on the amount of change in temperature in the head disk assembly and the amount of change in the current of the head disk assembly positioning drive motor VCM calculated from the positional difference between the current cylinder currently in use and the target cylinder for the next operation. A means for predicting a temperature change in the disk assembly, changing the air flow rate of the fan for cooling the head disk assembly, and keeping the temperature in the head disk assembly constant so as to eliminate the thermal off track. Magnetic disk device characterized by.