JPH02172089A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To extend the service life of a desiccative by providing a desiccative housing part in a housing, forming a ventilation hole between the above part and a base plate, disposing a filter in this hole, providing also a respiration hole through the housing part on the base plate, disposing a respiration filter in this hole and making the flow passage resistance of the ventilation hole large. CONSTITUTION:A magnetic disk 2 is rotated at high speed and a magnetic head 5 is slightly floated by an airflow caused by the rotation, so that information is magnetically recorded and reproduced. Then, the inside of an assembly body for the head and disk is under the hermetically sealed state, and an airflow generated by a pressure difference between the inside and the outside is allowed to pass through the respiration filter 9 incorporating the desiccative 8 provided in the ventilation hole 10. Then, the ventilation hole 10 is provided on the housing 12 as well, where the respiration filter 9 incorporating the desiccative 8 is also provided in this hole, whereas only this ventilation hole 10 is settled as large for its flow passage resistance. By this method, at the time of working a coil assembly body 7, a moisture content absorbed by the desiccative 8 is expelled by heating, and at the time of stopping, infiltration of an external moisture content is suppressed as much as possible by the desiccative 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device having a function of dehumidifying the air inside a head disk assembly in which a magnetic head and a magnetic disk are housed in a sealed container. .

[Conventional technology]

A conventional magnetic disk drive having a head disk assembly (hereinafter referred to as HDA) in which a magnetic head and a magnetic disk are housed in a sealed container includes a magnetic disk 22 attached to a spindle 23 and a magnetic disk 22 attached to the spindle 23, as shown in FIG. a magnetic head 25 for recording and reproducing information;
The arm holder 26 that holds the rear end of the head arm 24, the coil assembly 27 fixed to the arm holder 26, and the arm holder by applying a driving force to the coil assembly 27. a magnetic head positioning mechanism having a magnetic circuit 31 for driving the magnetic circuit 31, a housing 32 for housing the magnetic circuit 31, a desiccant 28 for dehumidifying the internal air, and a desiccant case 33 for housing the desiccant 28; A base plate 21 accommodates these and seals the air inside.

The above-described magnetic disk device magnetically performs information recording and reproducing operations while the magnetic head 25 is levitated from the magnetic disk 22 at minute intervals by airflow generated by rotating the magnetic disk 22 at high speed. . A breathing filter 29 is attached to the base plate 21 for communicating with outside air in order to avoid sudden pressure changes inside the HDA. In addition, since the humidity inside the HDA increases due to the intrusion of outside air, a desiccant case 33 is installed inside the HDA to dehumidify this, and a desiccant 28 is placed inside the desiccant case 33. Dehumidification is carried out through the provided ventilation holes 30.

[Problem to be solved by the invention]

As described above, in the conventional magnetic disk drive, a desiccant case containing a desiccant agent is installed inside the HDA in order to keep the humidity inside the HDA low. For this reason, a space is required to accommodate the desiccant case, and when the magnetic disk drive is stopped and highly humid outside air flows in, it takes time to dehumidify.
This has the disadvantage that the humidity inside the DA increases, causing the magnetic disk and magnetic head to stick to each other. Additionally, there is a limit to the amount of desiccant that can be placed inside the HDA, so if the HDA is left in a high humidity environment, the desiccant will reach a saturated state within a short period of time, causing the inside of the HDA to become saturated. Another drawback is that it becomes impossible to keep the air humidity low.

[Means to solve the problem]

A magnetic disk device of the present invention includes a head arm that holds a magnetic head at its tip, an arm holder that mounts the head arm, a coil assembly that is fixed to the arm holder, and a driving force that applies a driving force to the coil assembly. magnetic circuit,
A magnetic head positioning mechanism including a housing that houses the magnetic circuit, a magnetic disk on which information is recorded and reproduced by the magnetic head, and a spindle that rotates with the magnetic disk mounted thereon, the magnetic head positioning mechanism and In a magnetic disk drive having a base plate that seals and accommodates the spindle, a desiccant storage section is provided in the housing, a ventilation hole is provided between the desiccant storage section and the base plate, and a filter is provided in the ventilation hole. , a breathing hole communicating with the desiccant storage section is provided in the base plate, a breathing filter is provided in the breathing hole, and a flow path resistance of the ventilation hole in which the filter is provided is such that the flow path resistance of the ventilation hole in which the breathing filter is provided is The desiccant is stored in the desiccant accommodating portion, and the desiccant is set to be larger than the flow path resistance of the breathing hole provided.

〔Example〕

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

FIG. 1 is a sectional view showing an embodiment of the present invention.

In FIG. 1, a base plate 1 has a rotating magnetic disk 2 attached to a spindle 3, a magnetic head 5 for magnetically recording and reproducing information on the magnetic disk 2, and a magnetic head 5 held at its tip. a head arm 4; an arm holder 6 on which the head arm 4 is mounted;
A coil assembly 7 fixed to the arm holder 6 and a magnetic circuit 11 that provides a driving force to the coil assembly 7.
A magnetic head positioning mechanism having a housing 12 containing a magnetic circuit 11 and a desiccant 8 is housed therein, and the air inside is sealed.

When the magnetic disk 2 is rotated at high speed, an airflow is generated, and this airflow causes the magnetic head 5 to levitate from the magnetic disk 2 with a small gap, and in this levitated state, information is magnetically recorded and reproduced. The inside of the HDA is sealed, and the air pressure changes due to the heat generated inside the HDA, creating a pressure difference between the outside and inside of the HDA and allowing air to flow. Therefore, a breathing filter 9 is installed in the air hole. has been done. This breathing filter 9 is provided at a position where outside air can flow through the desiccant 8 housed in the housing 12. Further, the housing 12 is provided with a vent hole 10 that allows communication between the desiccant 8 and the inside of the HDA and has a flow resistance greater than that of the breathing filter 9. It is arranged.

By using the HDA configured as above, H
When the DA is in operation, the housing 12 is heated by heat radiation from the coil assembly 7, so the desiccant 8 discharges absorbed moisture, and this discharged moisture passes through the breathing filter 9, which has a relatively low flow resistance. Most of it is discharged through the Furthermore, when the HDA is stopped, air from outside the HDA enters the HDA through the breathing filter 9, but the moisture in the air is absorbed by the desiccant 8, and the air enters the HDA through the ventilation hole 10 in which the filter is installed. leaks inside.

〔Effect of the invention〕

As explained above, the magnetic disk drive of the present invention includes a portion for accommodating a desiccant in a housing that accommodates a magnetic circuit, and a ventilation hole is provided between the desiccant accommodating portion and the base plate. By installing a breathing filter in the air hole and making the flow path resistance of the air hole where the filter is installed greater than the air flow path with the outside where the breathing filter is installed,
When the HDA is in operation, the moisture absorbed by the desiccant is discharged, and most of the moisture flows out of the HDA through a breathing filter with low flow resistance. Since outside air flows into the desiccant in the housing through the breathing filter and then into the HDA, semi-permanent use is possible even with a limited amount of desiccant, and the air inside the HDA is constantly It has the effect of keeping it dry. Another advantage is that the device can be made more compact because the space used for conventional desiccant cases is no longer required.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing an example of a conventional magnetic disk device. 1.21... Base plate, 2.22... Magnetic disk, 3.23... Spindle, 4.24... Head arm, 5.25... Magnetic head, 6.26...
・Arm holder, 7.27...Coil assembly, 8.2
8... Desiccant, 9.29... Breathing filter, 1o.
3゜...Vent hole, 11.31...Magnetic circuit, 12.
32... Housing, 33... Desiccant case.

Claims (1)

[Claims] a head arm that holds a magnetic head at its tip; an arm holder that mounts the head arm; a coil assembly that is fixed to the arm holder; a magnetic circuit that provides a driving force to the coil assembly; a magnetic head positioning mechanism having a housing for accommodating the magnetic head; a magnetic disk on which information is recorded and reproduced by the magnetic head;
In the magnetic disk device, the magnetic disk device includes a spindle that rotates with the magnetic disk mounted thereon, and a base plate that seals and accommodates the magnetic head positioning mechanism and the spindle, wherein a desiccant storage section is provided in the housing, and the desiccant storage section is provided in the housing. A ventilation hole is provided between the desiccant storage part and the base plate, a filter is provided in the ventilation hole, a breathing hole communicating with the desiccant storage part is provided in the base plate, and a breathing filter is provided in the breathing hole. , the flow path resistance of the ventilation hole in which the filter is disposed is set to be greater than the flow path resistance of the breathing hole in which the breathing filter is disposed, and a desiccant is stored in the desiccant storage section. A magnetic disk device featuring: