JPH02257478A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent misalignment of a data head by equalizing a carriage, head holders and plural fixing members for fixing them in coefficient of linear expansion. CONSTITUTION:Three screws 17 are provided at appropriate intervals as the fixing members for fixing the head holders 15A-15C to the carriage 16. Materials for constituting these head holders 15A-15C, carriage 16 and screws 17 are of an equivalent coefficient of linear expansion respectively. Consequently, even when expansion and shrinkage due to a temp. change take place, the head holders 15A-15C are not deformed since no bimetal effect is generated, and hence a vibration proofing effect is improved. By this method, the head holders 15A-15C are free from involvement in thermal deformation and vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to an improvement of a head holder fixing portion thereof.

[Conventional technology]

FIG. 3 is a perspective view showing a schematic configuration of a head holder fixing section in a conventional magnetic disk device, similar to that shown in, for example, Japanese Patent Application Laid-Open No. 63-866.

In this figure, (IA) and (IB) are magnetic disks,
(2) is servo information written in advance on the top surface of the magnetic disk (IA), and (3) is a servo head for reading the servo head, which is disposed on the top surface of the magnetic disk (IA).

(4) is a data head disposed on the bottom surface of the magnetic disk (IA), which writes information to or reads information from the magnetic disk (IA). Note that although only the data head corresponding to the magnetic disk (IA) is shown, the data head is similarly arranged for the magnetic disk (IB).

(5A) (5B) (5C) is a head holder that supports the servo head (3) or data head (4), (58) is for supporting the servo head (3), and (5B) is a head holder for supporting the servo head (3). (A) is for supporting, and (5C) is for supporting other data not shown.

(6) is a carriage, and the opening is a screw that is a fixing member for fixing each of the above head holders to the carriage.The head holders (5A), (511), and (5C) are stacked and integrated as shown, and the carriage ( 6) is fixed.

In such a configuration, magnetic disks (IA) (IB
> rotates at a constant speed, and the head holder (5B) (
Writing and reading of signals are performed through a data head fixed to the 5C).

Also, one of the magnetic disks (
By reading out the servo information (2) written on the top surface of IA), position information is obtained, and a closed loop control system for positioning (not shown) is operated, and the carriage (6) rotates to determine the position of the servo head. controlled.

On the other hand, the servo head (3) and the data head (A) are fixed to the carriage (6) via head holders (5A) (5B) (5C), and each has a magnetic disk (IA).
) (In) is held in a straight line parallel to the rotation axis of the servo head (3).
When the data head (a) is positioned correctly, the data head (a) is also positioned correctly.

[Problem to be solved by the invention]

A conventional magnetic disk drive is constructed as described above, and the head holder (5A>(5B> (5C)) and carriage (6) are fixed with a screw (7). If you use the head holder, there is a disadvantage that the head holder will easily vibrate.Also, even if you use multiple screws, if there is a difference in linear expansion coefficient between the head holder and the carriage, the bimetal There is a drawback that the head holder is deformed due to the effect.

Furthermore, when the head holder is thermally deformed, if the deformation is uneven, the servo head (31) and all the data heads (2) will no longer be located on a straight line parallel to the rotation axis of the magnetic disk. Therefore, even if the servo head is positioned, the data head may be misaligned, causing signal writing and
There is a problem that reading is not performed correctly.

Furthermore, if the coefficient of linear expansion of the head holder is larger than that of the screw, the compressive load from the screw on the head holder increases as the temperature rises, and the head holder (
5A>(5B> (5C) When a compressive load exceeding the stress-strain proportional limit or proof stress is applied, the dimensional accuracy will decrease even after the temperature returns to room temperature and the compressive load is released. 1986 I+ issue)
It has been reported in Furthermore, if the temperature drops,
The axial force of the screw decreases and the head holder (5A) (5B
) (5C) becomes more likely to vibrate.

When the head holder vibrates, it adversely affects the closed-loop control of positioning, and as a result stable positioning is no longer performed, the data head also shifts in position, making it impossible to write and read signals correctly.

The present invention has been made to solve the above-mentioned problems, and aims to provide a magnetic disk device that does not cause thermal deformation or vibration of the head holder.

[Means to solve the problem]

The magnetic disk device according to the present invention is such that the linear expansion coefficients of the carriage, the head holder, and the fixing member for fixing both are made equal, and a plurality of fixing members are provided.

Further, when the head holder is fixed to the carriage using a fixing member, the combination is such that the stress generated in each member is smaller than the stress-strain proportional limit or proof stress of each material within the operating temperature range.

Furthermore, the fixing member is screw- or pin-shaped, and its center line is substantially aligned with the radial direction of the magnetic disk.

[For production]

According to this invention, the linear expansion coefficients of the carriage, the head holder, and their fixing members are equalized, and the stress generated in each member of the carriage and the head boulder 1 fixing member is reduced within the operating temperature range. - Since the combination is made so that the strain is smaller than the proportional limit or proof stress, or the center line of the screw or bottle-shaped fixing member is made to almost coincide with the radial direction of the magnetic disk,
Even if the head holder expands and contracts due to temperature changes, the relative relationship between them does not change, so the head holder does not undergo thermal deformation.Also, since multiple fixing members are provided, as mentioned above, the vibration of the head holder does not change. It also does not occur.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a perspective view showing the schematic structure of the embodiment, (158)
(15B) (15c) to each end holder (
16) is a carriage for fixing each of the above head holders;
(17) Do not fix the head holder to the carriage.

Three screws are provided at appropriate intervals as the second fixing member. These head holders, carriages, and screws all have almost the same external configuration as conventional ones, but they differ from conventional ones in that the materials that make up each have the same coefficient of linear expansion. . The rest of the configuration is the same as the conventional one, so the explanation will be omitted.

With this structure, even if there is expansion and contraction due to temperature changes, the ratio is the same, there is no change in the relative relationship, and no bimetallic effect occurs, so there is no compression from the side to the head holder. The head holder will not be deformed due to increased load, and the axial force of the screw will not decrease and rattling will not occur.Furthermore, the head holder and carriage are fixed with multiple screws. The anti-vibration effect is also improved. FIG. 2 shows another embodiment of the invention, in which a carriage (!6) has a base (160) and three support parts (16A) projecting from the base in an E-shape.
(16B> (16c), the base (160) has a rotating shaft <16E), and each support part has a head holder (
158) (1511) (15C) are each fixed by two screws 17), and the screws (17) are arranged so that their center lines coincide or almost coincide with the radial direction of the magnetic disk (IA> (In)). The other configurations are the same as the embodiment shown in Fig. 1.This embodiment also operates in the same manner as the embodiment shown in Fig. 1, and the same effects can be expected. .

In addition, in the above description, an embodiment was shown in which the servo head (3) and the data head (A) are positioned by rotating the carriage (16).
) is moved linearly to position the servo head and data head, a similar effect can be expected.

Further, although an example has been shown in which the servo head (3) is provided on the upper surface of the uppermost magnetic disk, it may be provided on any surface of any magnetic disk.

Furthermore, the servo head (3) reads the servo information (2) written on the top surface of the magnetic disk (IA) and performs closed loop control to position the servo head (3) and the data head (4). Although the embodiment has been shown, the data head (A) may read the servo information (2) and perform closed loop control to position the data head (4), or open loop control may be used to position the data head (4). The head (4) may be positioned, and in the above embodiment, the head holder (+5A) (15B)
(15C), the carriage (16), and the screw (17) all have the same coefficient of linear expansion, but the head holder (15A) (158) (15C) is fixed to the carriage (I6) with the screw (17). In this case, the same effect can be expected even if the combination is such that the stress generated in each is smaller than the stress-strain proportional limit or proof stress of each material within the operating temperature range. may be formed of a bottle-shaped material instead of a screw.

〔Effect of the invention〕

As described above, according to the present invention, the coefficients of linear expansion of the carriage, the head holder, and the plurality of fixing members that fix these are made equal, and the carriage, the head holder,
The fixing members are combined so that the stress generated in each member is smaller than the proportional limit of stress strain or proof stress of each member within the operating temperature range, or the center line of the screw or bottle-shaped fixing member is aligned with the magnetic disk. Since the radial direction of the data head is substantially aligned with the radial direction of the data head, it is possible to effectively prevent displacement of the data head.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an embodiment of the present invention;
FIG. 2 is a perspective view showing a schematic structure of another embodiment of the present invention, and FIG. 3 is a perspective view showing a schematic structure of a conventional magnetic disk device. In the figure, (IA) <IB) is a magnetic disk, (2)
is servo information, B) is servo head, (a) is data head, (5A) (5B> (5C) (15A) (
15B> (15c) is the head holder (61 (16)
is a carriage, and (71 (17) is a screw. In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A head holder that supports a head such as a data head that writes and reads information on a magnetic disk, or a servo head that reads servo information written in advance on the magnetic disk for positioning the data head, and a head holder. 1. A magnetic disk drive comprising a plurality of fixing members fixed to a carriage, the head holder, the carriage, and the fixing members having equal coefficients of linear expansion. (2) A head holder and a head holder that support a head such as a data head that writes and reads information on a magnetic disk or a servo head that reads servo information written in advance on the magnetic disk for positioning the data head. A plurality of fixing members fixed to the carriage are provided, and the stress generated in each of the head holder, the carriage, and the fixing member is smaller than the stress-strain proportional limit or proof stress of each material in the operating temperature range. A magnetic disk device characterized in that it can be combined in the following manner. (3) A head holder that supports a head such as a data head that writes and reads information on a magnetic disk, or a servo head that reads servo information written in advance on the magnetic disk for positioning the data head, and a head holder. 1. A magnetic disk drive comprising a plurality of screw or pin-shaped fixing members fixed to a carriage, the center line of the fixing members substantially coinciding with the radial direction of the magnetic disk.