JPS6332793A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To decrease malfunction of write/read even if the temperature difference is large and differs between the recording and reproduction by using an aluminum alloy material so as to decrease the difference of the linear expansion coefficient between a magnetic disk and a head arm of a magnetic head and make the relation of positive/negative coefficients constant. CONSTITUTION:Since the inter-disk temperature of a data head is lower than the inter-disk temperature of a servo head 5a, a linear expansion coefficient of the aluminum alloy material for the head arm of the magnetic head 5 is slightly larger than that for the magnetic disk 2 in order to minimize theoretically the thermal off-track caused by taking the temperature difference between disks at the information recording and reproduction and the temperature difference in the sealed case into account, and since the relations of 0.3X10<-6>/ deg.C<=alphaa-alphad<=0.9X10<-6>/ deg.C and alphaa-alphad>0 are taken, where alphad is the linear expansion coefficient of the disk and alphaa is the linear expansion coefficient of the head arm, even if the temperature in the sealed case differs largely between the information recording and reproduction, the thermal off-track quantity is small and malfunction in the information write/read is less.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic disk device, and particularly to a track following type magnetic disk consisting of a magnetic disk and a head arm of a magnetic head, each of which is made of an aluminum alloy material. Regarding equipment.

[Conventional technology]

Conventionally, in this type of magnetic disk device, the magnetic disk is manufactured from a high-purity aluminum alloy (specifically A3086) material.
The head arm of the magnetic head was made of cast aluminum alloy material.

[Problem that the invention seeks to solve]

In the conventional magnetic disk drive described above, the variation in the coefficient of linear expansion of the material of the magnetic disk is relatively small, but the coefficient of linear expansion of the magnetic head varies widely due to differences in casting method or aluminum purity. Because there is a large variation in the difference in linear expansion coefficient between the magnetic head and the magnetic head, if there is a temperature difference between recording and reproducing information, the relative positional relationship in the radial direction between the magnetic disk and the magnetic head will shift, resulting in so-called thermal off. This method has the drawback of causing a tracking phenomenon and causing malfunctions in writing and reading information.

[Means for Solving Problem C] The present invention has been made by focusing on the above-mentioned conventional problem, and it solves the problem of the magnetic disk and magnetic head that occurs when there is a temperature difference between recording and reproducing information. It is an object of the present invention to provide a magnetic disk device that can minimize the relative positional deviation in the radial direction of the magnetic disk and reduce malfunctions in writing and reading information.

To this end, the present invention provides a magnetic disk group, a spacer ring for stacking the magnetic disk group, a spindle for supporting and rotating the magnetic disk group, a clamp ring for fixing the magnetic disk group to the spindle, and information recording/reproducing. In a magnetic disk device comprising a plurality of magnetic heads for use in a vehicle and a carriage for holding and positioning the magnetic heads, the difference in coefficient of linear expansion between the magnetic disk group and the head arm of the magnetic head is small, and They are each made of an aluminum alloy material that has a constant positive/negative relationship.

〔Example〕

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

In the drawing, a spindle 1 has magnetic disks 2 stacked at regular intervals through a spacer ring 10, the magnetic disks 2 are fixed by a clamping ring 6, and a lower substrate 3. - They are rotatably attached to the upper substrate 4 via bearings (not shown), and are driven by dedicated motors (not shown).

A magnetic head 5 (read/write head) writes and reads data signals to and from the magnetic disk 2, and a servo head 5 records positioning signals (servo signals) and reads servo signals from the servo disk 2a.
The carriage 7 carrying the magnetic disk a performs linear reciprocating motion toward the center of the magnetic disk 2. In order to drive the reciprocating motion of the carriage 7, a magnetic circuit 8 made of permanent magnets is provided.The magnetic circuit 8 is attached to the upper substrate 4 and the lower substrate 3 via a frame 9, and The reciprocating motion of the carriage 7 is performed in cooperation with a provided coil (not shown).

These magnetic disks2. Carriage 7, magnetic throat 5
is the substrate plate 4. Lower board 3. It is covered by a frame 9 and a cover (not shown) and housed in a sealed case.

The magnetic disk device configured as described above operates as follows. When the magnetic disk 2 is driven by the motor and rotates together with the spindle 1, when a positioning command is received from the host device, the carriage 7 is instructed by a positioning control circuit (not shown) to perform a seek operation and move to the commanded predetermined position. At this point, information is recorded or reproduced using the magnetic head 5.

Therefore, the temperature inside the sealed case when recording and reproducing information may vary greatly due to temperature differences in the operating environment of the magnetic disk device and temperature differences due to differences in the time during which the spindle 1 is driven by the motor. .

In this embodiment, compared to the interplate temperature of the servo head 5a,
Since the temperature between the plates of the data head is lower, the thermal off-track that occurs when considering both the temperature difference between the plates and the temperature difference inside the sealed case when recording and reproducing information can be theoretically minimized. The head arm 11 of the magnetic head 5 is made of an aluminum alloy material whose linear expansion coefficient is slightly larger than that of the magnetic disk 2 (specifically, the linear expansion coefficient of the magnetic disk is αd). , if the linear expansion coefficient of the head arm is αa, then 0.3 X 10-'
/'C-<αa-αd 40.9 X 10"'/'C
), and αa-αd)Q material, the amount of thermal off-track is small even when the temperature inside the sealed case differs greatly between recording and reproducing information, making it easy to read and write information. Malfunctions are reduced.

In this embodiment, αa-αd)Q is used, but depending on the configuration of the magnetic disk device, αd-αa>0 may be obtained, and in this case, the same effect as the present invention is obtained.
It goes without saying that it is included in the present invention.

〔Effect of the invention〕

As explained above, the present invention enables recording and reproduction of information by forming the magnetic disk and the head arm of the magnetic head from an aluminum alloy material that has a slight difference in coefficient of linear expansion and has a constant positive/negative relationship. Even if the temperature difference differs from time to time, the amount of thermal off-track is small, resulting in a loss of information.

This has the effect of reducing malfunctions during reading.

[Brief explanation of the drawing]

The drawing is a sectional view showing a magnetic disk device according to an embodiment of the present invention. 1...Spindle, 2...Magnetic disk, 5...Magnetic disk, 7......
Carriage, 11...Head arm.

Claims (1)

[Claims] A spacer ring for stacking a group of magnetic disks, a spindle for supporting and rotating the group of magnetic disks, a clamp ring for fixing the group of magnetic disks to the spindle, a plurality of magnetic heads for recording and reproducing information, and holding the magnetic head. and a carriage for positioning, the magnetic disk group and the head arms of the plurality of magnetic heads are made of an aluminum alloy material with a slight difference in coefficient of linear expansion and a constant positive/negative relationship. A magnetic disk device characterized by forming each.