JPS60242550A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To suppress an increase in frictional torque based upon the attraction between a magnetic head and a magnetic disk by detecting the power source of a rotary drive source being turned on, and driving a positioning drive source for the magnetic head at the start of the rotation of the magnetic disk on the basis of the detection signal. CONSTITUTION:The magnetic head 5 contacts the magnetic disk 2 initially, so the frictional torque is larger than starting torque and the disk 2 is in an unrotatable state. When th power source PWR is turned on, a power-on resetting circuit 11 outputs a signal P and a switch circuit 16 operates a switch 15 to a terminal 15A. The signal P is inputted to a movement signal generating circuit 13, which outputs a constant-time signal R to move the head 5 slightly in the radial direction of the disk 2 by the positioning drive source 6. Consequently, the attraction between the head 5 and disk 2 is eliminated. Then, a rotary dirve source controlling circuit 12 controls the rotary driver source 1 synchronously with the resetting of the signal P and starts turning the disk 2. Thus, the disk 2 is driven to rotate smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device that prevents adhesion between a magnetic head and a magnetic disk so that the magnetic disk rotates smoothly at startup. It is something.

[Prior art]

1 and 2 show a magnetic disk device according to the prior art.

In the figure, 1 is a rotational drive source such as a spindle motor attached to the main body of the device (not shown), and the rotational drive source 1 has a rotational axis IA, and the rotational axis IA has a magnetic Disk 2 is fitted.

Here, the magnetic disk 2 has a rated rotation speed (for example, 360
0R, P, M).

Reference numeral 3 denotes a head arm attached to the main body of the apparatus so as to be movable in the radial direction of the magnetic disk 2 via a shaft 4; 5 a magnetic head attached to one end of the head arm 4 facing the magnetic disk 2; The head 5 writes information to and reads information from the magnetic disk 2 while floating with a gap of 0.5 .mu.m or less between the head 5 and the magnetic disk 2.

Reference numeral 6 denotes a positioning drive source such as a motor attached to the main body of the apparatus, and the positioning drive source 6 has a shaft 7. A steel belt 8 is wound around the shaft 7 of the positioning drive source 6. One end of the steel belt 8 is attached to the other end of the helad arm 3, and the other end is attached to the spring 9. It is constantly under tension.

The magnetic disk device according to the prior art is configured as described above, and its operation will be explained next.

The rotation drive source 1 is activated to rotate the magnetic disk 2, while the positioning drive source 6 is activated to move the magnetic head 5 in the radial direction of the magnetic disk 2, and after positioning it at a desired position, information is written and read. Execute.

By the way, in the conventional magnetic disk device configured as described above, since the magnetic head 5 and the magnetic disk 2 are in contact with each other when the magnetic disk 2 starts rotating, frictional torque is generated due to the attraction phenomenon between the two. Occur.

Therefore, the magnetic disk 2 cannot rotate unless the rotary drive source 1 outputs a starting torque greater than the frictional torque. The above-mentioned friction torque changes depending on the environmental temperature and humidity conditions in which the device is placed. The relationship between the friction torque and the environmental temperature and humidity is shown in FIG.

In FIG. 2, the vertical axis represents the friction torque TL, and the horizontal axis represents the time during which the magnetic head 5 was left in contact with the magnetic disk 2. In addition, in the figure, the circle mark indicates an environmental temperature and humidity of 25℃5.
The plot for condition A of 0% R, H is shown, and the X mark also shows the plot for condition B of 40° C. and 80% R, H. Further, TS indicates the starting torque output by the rotary drive source 1 at the start of rotation.

As shown in the figure, when the standing time is less than 24 hours, the starting torque TS is greater than the friction torque TL in both conditions A and B, so the rotary drive source 1 can rotate the magnetic disk 2. However, if the standing time becomes 48 hours or more, the friction torque TL exceeds the starting torque TS under condition B, and therefore, under such condition B, the magnetic disk 2 becomes unable to rotate.

As described above, in the magnetic disk drive according to the prior art, if the magnetic head is left in contact with the magnetic disk for a long time (if the magnetic head is left in contact with the magnetic disk, the friction torque TL will increase due to the attraction phenomenon between the two, and the rotation of the magnetic disk 2 will be slowed down). It had the disadvantage that it could become incapacitating.

[Summary of the invention]

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and the magnetic head is once moved in the radial direction of the magnetic disk before the rotation of the magnetic disk starts, thereby canceling the adhesion phenomenon between the two, thereby improving the environment. To provide a magnetic disk device capable of accurately starting a magnetic disk without being affected by temperature, humidity, etc.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 3 and 4. Note that the same components as those in the prior art are given the same reference numerals, and the description thereof will be omitted.

In the figure, 11 is a power-on reset circuit as a power-on detection means that detects the power-on of the power source PWR and outputs a power-on reset signal P for a predetermined period of time, and 12 is a power-on reset circuit that controls starting and stopping of the rotary drive source 1. Rotary drive source control circuit,
The rotary drive source control circuit 12 keeps the rotary drive source 1 in a stopped state while the power-on reset signal P is input even if the electric power gPWR is turned on, and on the other hand, when the power-on recent signal P is released and At the same time, a rotational drive signal Q is outputted to start the rotational drive source 1.

Reference numeral 13 denotes a movement signal generation circuit as a starting means, and the movement signal generation circuit 13 outputs a movement signal R by inputting the power-on reset throat signal P.

Reference numeral 14 denotes a positioning drive source control circuit for controlling the positioning drive source 6, and the control circuit 14 receives the movement signal R or a positioning signal PS from a control device (not shown) via a switch described later. There is. Here, the positioning drive source control circuit 14 inputs the movement signal R to start the positioning drive source 6 to slightly move the magnetic head 5 in the radial direction of the magnetic disk 2, and also inputs the positioning signal PS. By inputting the information, the positioning drive source 6 is controlled to magnetically move and position the throat 5 to a predetermined position.

Further, 15 is a switch, and 16 is a switching circuit that switches the sui-nochi 15 from the terminal 15A to the terminal 15B.The switch 15 is normally connected to the terminal 15B, and the switching circuit 16 is connected to the power-on reset signal. When P is input, the switching circuit 16 switches to the terminal 15A.

The magnetic disk device according to the present invention is configured as described above, and its operation will be explained next.

First, in the initial state shown in FIG. 4(a), the magnetic head 5 is in contact with the magnetic disk 2, so the friction torque TL is
is larger than the starting torque TS, therefore, the magnetic disk 2
is in a non-rotatable state.

Next, when the power supply PWR is turned on at time TO as shown in FIG. 4(b), the power-on reset circuit 11 outputs the power-on reset signal P shown in FIG. While the switch 15 is switched to the terminal 15A, the rotational drive source control circuit 12 does not rotate the magnetic disk 2 even if the power PWR is turned on.

Furthermore, since the power-on reset signal P is input to the movement signal generation circuit 13, the movement signal generation circuit 13 is activated at time T1. During T'2, the movement signal R shown in FIG. 4(d) is output to the positioning drive source control circuit 14, and as a result,
The positioning drive source 6 slightly moves the magnetic head 5 in the radial direction of the magnetic disk 2. As a result, the attraction phenomenon between the magnetic head 5 and the magnetic disk 2 is released, and therefore,
After time T1, the friction torque TL decreases and the starting torque TS
As a result, the magnetic disk 2 becomes rotatable.

Thereafter, in synchronization with the cancellation of the power-on reset signal P, the rotational drive source control circuit 12 controls the rotational drive source 1 using the rotational drive signal Q shown in FIG.
At the same time, the switching circuit 16 switches the switch 15 to the terminal 15B and inputs the positioning signal PS to the positioning drive source control circuit 14, thereby starting the positioning drive tA6.
positions the magnetic disk 5 at a predetermined position on the magnetic disk 2. Thus, the magnetic disk device becomes ready for writing and outputting information.

In the above embodiment, a case has been described in which a rotary motor is used as the positioning drive source, but if a step motor is used, the movement signal generating circuit 13 can be a pulse circuit. For those having a mechanism capable of moving the magnetic head 5 by one track with one pulse,
Adding only one pulse can produce a remarkable effect in canceling the adsorption phenomenon. Further, in the above embodiment, a rotary type positioning mechanism using the head arm 4 was shown as a positioning mechanism for the magnetic heel 5, but the present invention can be applied to a linear type positioning mechanism without detracting from the spirit of the invention.

Further, in the above embodiment, there is no particular restriction on the position of the magnetic head 5 on the magnetic disk 2 when the magnetic disk 2 is not rotating, but in many cases, a so-called landing zone is placed on the innermost or outermost circumference. is often provided. In such a case, the outer circumferential direction or the inner circumferential direction may be used as the moving direction.

〔Effect of the invention〕

As explained above, according to the present invention, since the magnetic head is configured to move when the rotation of the magnetic disk starts,
It is possible to suppress the increase in frictional torque due to the attraction phenomenon between the magnetic head and the magnetic disk, and therefore, it is possible to smoothly start the rotation of the magnetic disk, and there is an effect that a highly reliable rotation start can be obtained. .

[Brief explanation of the drawing]

FIG. 1 is a simplified configuration diagram of a magnetic disk device according to the prior art, FIG. 2 is a relationship diagram between friction torque and starting torque to explain the drawbacks of the prior art, and FIG. 3 is a configuration of a magnetic disk device according to the present invention. FIG. 4 is a time chart showing friction torque, power supply, power-on reset signal, and movement signal one rotation drive signal. 1... Rotation drive source, 2... Magnetic disk, 5...
Magnetic head, 6... Positioning drive source, 11... Power-on reset circuit (power-on detection means), 13...
Movement signal generation circuit (starting means). Agent Masuo Oiwa (and 2 others) Figure 1 ζ Figure 2 Procedural amendment (voluntary) 2. Name of the invention Magnetic disk device 3. Relationship to the person making the amendment Patent applicant address Chiyoda, Tokyo Ward Marunouchi 2-2-3 Name
(601) Mitsubishi Electric Corporation Representative Hitoshi Katayama 8th Department 4 Agent Address 2-2-3-5 Marunouchi, Chiyoda-ku, Tokyo Column for detailed explanation of the invention subject to amendment. 6. Details of the amendment (1) In the 19th line of page 2 of the specification, the phrase "of the steel belt 8" is amended to read "of the steel belt 8."that's all

Claims (1)

[Claims] A magnetic disk drive comprising: a rotational drive source for a magnetic disk; a magnetic head that remains in contact with the magnetic disk and floats above the magnetic disk when the magnetic disk rotates; and a positioning drive source for the magnetic head. a power-on detection means for detecting power-on of the source; and a starting means that operates based on a signal from the power-on detection means to drive the positioning drive source for the magnetic head for a certain period of time when the magnetic disk starts rotating. A magnetic disk device characterized by: