JPH0548298Y2 - - Google Patents

Description

[Detailed description of the invention] [Summary] A magnetic disk drive carriage in which a head arm made of a material with a large coefficient of linear expansion is laminated around a cylinder made of a material with a small coefficient of linear expansion, and the upper part is fixed to the cylinder with an arm holder. In this case, the arm holder is annular and has a springy shape, and the downward elastic force of the outer periphery of the arm holder presses the clamp part of the uppermost head arm and fixes the head arm to the cylinder, thereby making it possible to attach the head arm to the cylinder. Improves vibration characteristics and off-track characteristics.

[Industrial application field]

The present invention relates to a carriage for a magnetic disk device having a head arm stacked structure.

Conventionally, a magnetic disk device with a head arm stacked structure is sealed with a housing 1 and a cover 2 as shown in FIG.
It is fixed to the housing 1 via. The spindle 4 is rotated by a motor 6 located at the bottom.
In addition, the carriage for reading/writing information on the disk disk 3 has a head arm 7 attached to a cylinder 8 that is connected to a voice coil motor (VCM).
9. Note that the cylinder 8 is supported by a shaft 10 through bearings 11 at the top and bottom.
Note that 12 is an arm holder for fixing the head arm 7 to the cylinder 8.

The cylinder 8 must be lightweight and have small inertia in order to increase the seek speed, and must also be strong against vibrations in order to accurately position the head. Therefore, it is desirable that the cylinder 8 has a large Young's modulus and a small coefficient of linear expansion. For example, materials with high Young's modulus such as stainless steel (SUS).

Furthermore, since the center of gravity of the head arm 7 is located away from the shaft 10, it is desirable to use a light material that is less affected by inertia. For example, magnesium (Mg),
Examples include light materials such as aluminum (Al).

As mentioned above, it is desirable that the materials of the head arm 7 and the cylinder 8, which is its axis, are different; however, due to temperature changes in the magnetic disk device, differences in linear expansion coefficients due to differences in the materials of the head arm 7 and cylinder 8 may occur. The extension of the head arm 7 is large, and the head arm 7 is pressed down with excessive force, causing distortion in the head arm 7 and causing off-track.

Therefore, there is a need for a carriage that has a structure that has low inertia and is resistant to vibration, but that does not suffer from off-track due to temperature changes.

[Conventional technology]

FIG. 4 is a diagram illustrating a conventional carriage.

Figure 4 shows the carriage part of Figure 3, with 10
is the shaft, 8 is the cylinder, 7 is the head arm, 9 is the
VCM, 11 is bearing, 12 is arm holder,
13 is a screw.

A conventional carriage has a cylinder 8 made of a material with a high Young's modulus such as SUS, and a head arm 7 made of a light material such as aluminum (Al) or magnesium (Mg). It has a structure that holds down the head arm 7.

[Problem that the invention attempts to solve]

In conventional carriages, the cylinder 8 and the head arm 7 are made of different materials, and due to the difference in linear expansion coefficient (the linear expansion coefficient of the Mg head arm is approximately 1.6 times that of the SUS cylinder), the head arm 7 may change due to temperature changes in the magnetic disk device. The force of arrow a acts, and the force of arrow b acts on the arm presser 12, causing an extra force (approx. 350 kg force at a temperature change of 40°) to the clamp portion A of the head arm 7, which causes the head arm 7 to
The clamp portion of the head arm 7 is compressed and deformed (the amount of depression of the head arm 7 is about 10 μm). This caused a problem in that the head was misaligned and off-track occurred.

[Means for solving problems]

The above problem has been solved by the present invention, as shown in the principle diagram of the present invention in FIG. Clamp parts of multiple head arms made of materials with large coefficients are laminated,
An arm holder 1 in which a center hole is inserted into a shaft 10 in a magnetic disk drive carriage in which a clamp portion at the top of the stack is fixed to a cylinder by an arm holder.
2 has an annular springy shape, and the annular intermediate part is fixed to the upper end surface of the cylinder with a screw 13, and the annular outer peripheral part pushes down the uppermost clamp part of the stacked head arms with the elastic force acting downward, and the stacked head arms are stacked. The present invention is solved by a magnetic disk drive carriage characterized by having a fixed head arm fixed to a cylinder.

[Effect]

That is, by providing the arm holder 12 with spring properties, even if a difference in thermal expansion occurs between the head arm 7 and the cylinder 8 due to a temperature change in the magnetic disk device, the clamping portion of the head arm 7 by the arm holder 12 will remain stable. The stress shown by the arrow a generated in the head arm 7 is absorbed by the bending of the outer peripheral portion of the arm presser as shown by the arrow S. As a result, deformation of the head arm 7 can be suppressed, and off-track can be suppressed to a minimum.

〔Example〕

FIG. 2 is a diagram illustrating an embodiment of the present invention.
Note that the same reference numerals represent the same objects throughout the figures.

FIG. 2 shows a sectional view of the arm presser of the present invention.
In the embodiment, the arm presser 12 is made of a material with a small Young's modulus such as aluminum (Al), has a thickness T of 7 mm, and has a concave portion (diameter 40 mm x
A depth of 13 mm) is provided, and an annular shape with h=4 mm is provided with spring properties. In addition, the arm presser has shaft 10.
A screw hole 14 for tightening the arm presser 12 is provided in the center of the hole (diameter 26 mm) into which the arm presser 12 is inserted.
2 is fixed to the cylinder 8 by a screw 13 inserted into a screw hole 14, and the head arm 7 stacked on the cylinder is fixed to the cylinder by the downward elastic force of its outer circumference.

In the head arm laminated structure described above, the load applied to the head arm 7 by the arm presser fixed by the five screws 13 is about 1000 kg. The increase in load caused by holding the arm due to a temperature change in the magnetic disk device (Δt = 40°C) was 350 kg for a conventional rigid shape made of a material with a high Young's modulus such as SUS, but in this example Similarly, it was made of a material such as aluminum with a low Young's modulus and had a springy shape, so it weighed 50 kg. As a result, the compression deformation of the clamp portion of the head arm 7 is reduced. Furthermore, as the stress is absorbed by the bending of the arm presser 12, the deformation of the head arm 7 is suppressed, and the off-track amount is reduced to 1/2 to 1/3 compared to the conventional one.

[Effect of idea]

As explained above, according to the present invention, the arm retainer has spring properties and absorbs thermal stress caused by temperature changes in the magnetic disk device, thereby creating a structure with low inertia and strong vibration resistance. It became possible to prevent off-track.

[Brief explanation of the drawing]

Figure 1 is a diagram explaining the principle of the present invention, Figure 2 is a diagram explaining an embodiment of the invention, Figure 3 is a diagram explaining a conventional magnetic disk device, and Figure 4 is a diagram explaining a conventional carriage. This is a diagram. In the figure, 7 is a head arm, 8 is a cylinder, 9 is a VCM, 10 is a shaft, 11 is a bearing,
12 is an arm holder, 13 is a screw, and 14 is a screw hole.

Claims (1)

[Scope of utility model registration request] Clamp portions of a plurality of head arms made of a material with a large coefficient of linear expansion are stacked around a cylinder made of a material with a small coefficient of linear expansion that is rotatably supported around the shaft 10 via a bearing, and a clamp on the top of the stack is stacked. In the carriage of a magnetic disk device in which a portion is fixed to a cylinder by an arm holder, the arm holder 12 whose central hole is inserted into the shaft 10 has an annular springy shape, and the annular intermediate part is fixed to the upper end surface of the cylinder with a screw 13. What is claimed is: 1. A carriage for a magnetic disk device, characterized in that the annular outer periphery presses down the uppermost clamp portion of the stacked head arms with an elastic force acting downward, thereby fixing the stacked head arms to the cylinder.