JPS61210573A - Disc driver - Google Patents

Abstract

PURPOSE:To eliminate deformation due to different in thermal expansion coeffi cient by tightening two kinds of arms with different thermal expansion coefficients via the 3rd member having a thermal expansion coefficient between those of both the arms in tightening the arms. CONSTITUTION:The 3rd spacer 22 having thermal expansion coefficient alpha3 which is between thermal expansion coefficients alpha1 and alpha2 of the head arm 3 and the flex arm 6 is given and both the arms 3 and 6 are tightened together via the spacer 22. The thermal expansion coefficients have the relation of alpha1>alpha3>alpha2, and the relation of L1alpha1+L2alpha2=L3alpha3 is satisfied by selecting L1, L2, L3, alpha1, alpha2, alpha3 so that the elongation of the tightened face L3 is equal to the elongation sum L1+L2 even when temperature changes and the difference in thermal expansion is eliminated, where L1 is a distance 102 between the tightened faces, L2 is a distance 103 and L3 is a distance 104. Thus, an off-track due to temperature fluctuation is reduced to improve the positioning accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a disk drive device, and particularly to a head positioning mechanism thereof.

[Background of the invention]

As a positioning mechanism for a hard disk drive, a structure as shown in FIG. 8 of Japanese Patent Laid-Open No. 58-70470 is generally used, and the arm 130 and the spacer 136 are generally made of the same material.

However, depending on the structure of the device, etc.,
As shown in the '574 publication and FIG. 3, it is necessary to use materials with different coefficients of thermal expansion. At this time, the two bolts on the fastening surface are deformed due to thermal strain, causing off-track.

[Purpose of the invention]

An object of the present invention is to eliminate deformation caused by differences in thermal expansion coefficients when joining members having different coefficients of thermal expansion;
This aims to improve the positioning accuracy of the disk device.

[Summary of the invention]

In a disk device, it is sometimes necessary to combine two members with different coefficients of thermal expansion, but it is possible to connect both members through a third member with an arbitrary coefficient of thermal expansion between the two members. It is.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

First, the overall configuration of the hard disk drive will be explained with reference to FIG.

A spindle motor 10 is attached to the pace 7, and a single plate or a plurality of discs 9 are attached to this with a clamp 15 via a spacer 14.

A head l for reading and writing data is attached to a gimbal 2 and a head arm 3. A flex arm 6 is supported by a base via a bearing 20 and a shaft 8, and a steel pel 12 is attached to one side. A capstan 2 is attached to the tip of the step motor 11 attached to the base.
There is 1, and 12 (which bell is ahead) is wrapped around it. The head arm 3 is attached to this flex arm 6. In addition, a filter 18 for cleaning the inside is inserted into the filter, and sealed by a Harakin 17 and a cover 16. Then, there is a frame 19 and an electric circuit section 13.

A disk 9 is rotated by a spindle motor 10, and the head is accurately positioned at a predetermined location by a carriage mechanism of a belt and an arm driven by a step motor. The voltage read by the head is then converted into necessary information by the circuit section 13.

In the case of open-loop control that does not have a servo mechanism and is driven by a step motor, etc., it is necessary to prevent the head l from off-tracking at any temperature due to thermal deformation caused by the ambient temperature of the entire device or changes in its own temperature. It is necessary to select the coefficient of thermal expansion of each member depending on the device structure. In this case, members having different coefficients of thermal expansion may be fastened together using two bolts.

Next, the main part of the present invention will be explained with reference to FIG.

a third spacer member 2 having a coefficient of thermal expansion between the coefficients of thermal expansion of the head arm 3 and the flex arm 6;
2, and both members 3 and 6 are connected through this spacer 22.
are characterized in that they are fastened to each other. Toe spacer 2
Let α3 be the thermal expansion coefficient of
, 103 is Lz and 104 is L3, Llα1+L
Lt l Lm + that satisfies the relationship 2α2=Lsα3
Lm sα1. α2. If α3 is selected, even if the temperature changes, the elongation of the fastening surface L3 and the elongation of LH+Lz will be the same, there will be no difference in thermal expansion, and off-track due to deformation will not occur.

In the figure, of the three fastening bolts, a.

If b is made of the same stainless steel as the member 22, there will be no relative deviation in the axial direction due to temperature changes, but in c, the head arm 3 is aluminum die-cast and the flex arm 6 is
If it is made of carbon steel, the difference in coefficient of thermal expansion will cause a relative misalignment in the axial direction, resulting in a change in the tightening force. Therefore, in this embodiment, by providing a counter seat in the flex arm 6 and selecting the depth of the counter seat, relative displacement of the bolt in the axial direction can be prevented.

FIG. 3 shows a conventional example in which the head arm 3 and the flex arm 6 are directly connected. In this example, the thermal expansion coefficient of the head arm is α11, that of the flex arm is α2, and αl>α3. In this case, between the two bolts, if the bolt 101 between the bolts is L, there will be a difference due to thermal expansion of L (α1 - α2] × ΔT = Δt due to the temperature difference ΔT, but the bolts forcefully fasten the bolts. As a result, internal distortion occurs, which results in deformation and appears as off-track between the head arm 3 and the disk.

〔Effect of the invention〕

As described above, according to the present invention, there is no deformation due to temperature change due to the difference in coefficient of thermal expansion K, so there is an effect of reducing off-track due to temperature fluctuation and improving positioning accuracy.

[Brief explanation of drawings]

FIG. 1 is an overall structural diagram of a hard disk shaft device, FIG. 2 is a side view of a main part of a head arm to which the present invention is applied, and FIG. 3 is a side view of a conventional head arm. 1...Head, 2...Gimbal, 3...Head arm, 4...Arm spacer, 5...Head arm bolt, 6...Flex arm, 7...Pace, 8... ... Pivot shaft, 9... Disc, lO...
・Spindle motor, 11...Step motor, 12
...Steel belt, 13...Circuit section, 14...
Disc spacer, 15... Disc clamp, 16
...Ka<-117...ノ(tsukin, 18...filter, 19...frame, 20...bearing, 21
...Capstan, 22...Spacer, 23...
Bolt for flex arm. ``Represented by Patent Attorney Katsuo Ogawa ~ ``Ministry 1 Figure

Claims (1)

[Claims] A disk device comprising a single magnetic recording medium plate or a plurality of magnetic recording medium plates, a head corresponding to the magnetic recording medium plate, an arm for moving the head, a support mechanism for supporting the arm, a drive device for driving the arm, and a sealing device for sealing all of these, A disk drive device characterized in that when two types of arms having different coefficients of thermal expansion are fastened together, they are fastened through a third member having a coefficient of thermal expansion that falls between the coefficients of thermal expansion of both arms.