JPS6148179A - Magnetic head actuator - Google Patents

Abstract

PURPOSE:To eliminate deflection of shaft of a carriage even when the ambient temperature rises by fitting a ring compensating member having an equal thermal expansion coefficient as a bearing constituting member to a bearing fit part of a fixed shaft inserting part of the carriage in pressing state. CONSTITUTION:An access arm 2 is provided to a carriage 1, an iron made ring compensating member 21 having a thermal expansion coefficient equal to that of a bearing 3 is fitted to the bearing fitting part of the fixed shaft fit part in a pressing state by pressing, shrinkage fit or casting and the bearing 3 is fitted to the inside of the ring compensation member 21. Even if the temperature of the carriage 1 rises due to ambient temperature, the thermal expansion difference between the carriage 1 having a large thermal expansion coefficient and the bearing 3 is compensated sufficiently by the ring member 21 fitted in pressing state due to pressing, shrinkage fit or casting to the bearing fit part of the carriage 1 and no gap is caused between the both.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic seven-door actuator used in a magnetic disk device, and in particular, the present invention relates to a magnetic seven-door actuator used in a magnetic disk device, and in particular, the present invention relates to a magnetic seven-door actuator used in a magnetic disk device. The present invention relates to an improvement in a swing-type magnetic head actuator that can be accurately positioned at a predetermined track position.

Magnetic disk drives used as file devices in computer systems are becoming larger and faster as main computers improve in performance and become larger.
High-speed operability that enables shortening of the access time of magnetic heads to magnetic disks and high-precision positioning has become an extremely important issue.

In order to satisfy such high-speed operation, it is necessary to reduce the weight of each movable part. For example, in an oscillating magnetic head actuator for positioning the magnetic head, the movable part of the actuator, that is, the carriage, is made of aluminum. CAN), magnesium (Mg), and other light alloys.

However, because the thermal expansion coefficients of the carriage and the intervening bearing used to rotatably attach the carriage to the fixed shaft are different, fluctuations in the environmental temperature at the location where the device is installed and the heat generation temperature within the device may cause the thermal expansion coefficient to differ. There is a problem in that the fitting precision between the carriage and the bearing is reduced, and as a result, it becomes difficult to accurately position the magnetic head by the actuator, and there is a desire to eliminate this inconvenience.

[Conventional technology]

Conventionally, a swinging magnetic head actuator used in a magnetic disk device has a carriage 1 equipped with an access arm 2 that supports a magnetic head mechanism (not shown), as shown in FIG. 3, to reduce weight. Aluminum (AJ
) or a light alloy such as magnesium (Mg).

Further, the carriage 1 is rotatably attached to a fixed shaft 4 provided on the base 5 side via a steel bearing 3, and the carriage 1 can be rotated at a predetermined angle using the fixed shaft 4 as a fulcrum. Accordingly, the magnetic helad is positioned at a predetermined track position on a rotating magnetic disk (not shown).

[Problem that the invention seeks to solve]

However, in the magnetic head actuator having the above configuration, the structural members of the carriage 1 and the
Since the thermal expansion coefficient of the bearing 3 is different from that of the structural members of the bearing 3, which is fitted into the bearing 3, wind damage caused by the rotation of the magnetic disk during operation of the device, temperature rise due to heat generated from other moving parts, etc. Due to fluctuations in the temperature of the installation environment, the fitting precision between the carriage 1 and the bearing 3 is reduced.

That is, aluminum (AJ
), or a light alloy such as magnesium (Mg) has a thermal expansion coefficient of iron (Fe), which is a component of the bearing 3: 10
．． It has a thermal expansion coefficient of about 23 x 10-' deg -' which is about twice that of 8 x 10-' deg -'.

Therefore, for example, the temperature at the fitting portion between the carriage 1 and the bearing 3, which has a fitting diameter of 30 mm and is assembled in a fitting manner, is
If the environmental temperature rises by 20℃, approximately 16
Since a gap as large as μm occurs, shaft runout occurs between the two, making it difficult to accurately position the magnetic head at a predetermined trunk position on the rotating magnetic disk.

In particular, in recent years, magnetic disks used in magnetic disk drives have been proposed with recording track widths of 20 μm or less, which have drawbacks that pose a major practical obstacle.

Therefore, in order to eliminate the above-mentioned shaft vibration, the carriage 1
It is conceivable that the bearing 3 is press-fitted with a tightening margin into the fitting part of the bearing 3 in the fixed shaft fitting part of the bearing 3, but in this case, stress due to tightening is always applied to the bearing 3. , bearing 3
This may adversely affect the movement accuracy and life of the machine.

[Means for solving problems]

The above problem consists of a carriage equipped with a magnetic head access arm and a fixed shaft to which the carriage is rotatably inserted via a bearing.By rotating the carriage at a predetermined angle using the fixed shaft as a fulcrum, An actuator for positioning a magnetic head at a track position on a rotating magnetic disk, the bearing being fitted into a fixed shaft insertion portion of a carriage under pressure and having a coefficient of thermal expansion equal to that of the bearing component. This problem is solved by the magnetic head actuator according to the present invention, which has a configuration in which the magnetic head actuator is configured to be fitted through a ring compensation member.

[Effect]

That is, a ring compensating member having a coefficient of thermal expansion equal to that of the bearing component is fitted into the bearing fitting portion of the fixed shaft insertion portion of the carriage under pressure by press fitting, shrink fitting, casting, etc.; By arranging the bearing to fit within the ring member, even if the environmental temperature of the device increases, there will be no gap between the fitting portion of the carriage and the outer ring portion of the bearing, which have different coefficients of thermal expansion.
This eliminates axial wobbling of the carriage inserted into the fixed shaft.

Therefore, at a predetermined trunk position on the rotating magnetic disk,
The actuator makes it possible to position the magnetic head with good viscosity.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1 and 2 are a plan view and a sectional view of a main part of an embodiment of a magnetic head actuator according to the present invention.

In both figures, 1 is a carriage made of a light alloy such as aluminum (Aj) or magnesium (Mg) to reduce weight, 2 is an access arm that supports a magnetic head mechanism (not shown), and 3 4 is a steel bearing, and 4 is a fixed shaft provided on the base portion 5.

The access arm 2 supporting the magnetic head mechanism (not shown) is attached to the carriage 7l as in the conventional case, and the bearing 3 and the bearing fitting part in the fixed shaft insertion part are attached to the access arm 2, which supports the magnetic head mechanism part (not shown). Iron (Fe) with an equivalent coefficient of thermal expansion
A ring compensating member 21 made of, for example, manufactured by Y.M. Co., Ltd. is fitted in a pressurized state by press fitting, shrink fitting, casting, etc., and the bearing 3 is fitted inside the ring compensating member 21.

With this configuration, even if the temperature of the carriage 1 rises due to the environmental temperature of the device, the difference in thermal expansion between the carriage 1 and the bearing 3, which have a large coefficient of thermal expansion, will cause the bearing fitting portion of the carriage 1 to The ring member 2 is fitted under pressure by press-fitting, shrink-fitting, casting, etc.
Enough by 1? lIi is compensated for, and there is no longer a gap between the two.

Therefore, at the actual environmental temperature of the apparatus, the axial vibration of the carriage 1 with respect to the fixed shaft 4 is eliminated, and the magnetic head can be positioned with high precision by the actuator.

〔Effect of the invention〕

As is clear from the above description, according to the magnetic head actuator according to the present invention, the magnetic head can be operated without being affected by temperature rises inside the device in practical use or fluctuations in the temperature of the installation environment of the device. This has an excellent advantage in that it is possible to position the magnetic disk at a predetermined trunk position with high precision.

Therefore, it is possible to increase the density of recording tracks on the magnetic disk, and as a result, it is possible to increase the capacity of the magnetic disk device.

[Brief explanation of the drawing]

1 and 2 are a plan view and a sectional view of a main part showing an embodiment of a magnetic head actuator according to the present invention, and FIG. 3 is a sectional view of a main part to explain a conventional magnetic seven-door actuator. It is. In the figure, 1 is a carriage, 2 is an access arm, 3 is a bearing, 4 is a fixed shaft, and 21 is a ring compensation member. -5: Figure 1 Figure 2 gl Figure 3

Claims (1)

[Claims] It consists of a carriage equipped with a magnetic head access arm, and a fixed shaft into which the carriage is rotatably inserted through a bearing.By rotating the carriage at a predetermined angle using the fixed shaft as a fulcrum, it is possible to read information on a rotating magnetic disk. an actuator for positioning a magnetic head at a track position, the bearing being mounted on a rotating shaft insertion portion of a carriage, having a coefficient of thermal expansion equal to that of the bearing component;
A magnetic head actuator characterized in that the magnetic head actuator is fitted with a ring compensating member which is fitted in a pressurized manner.