JPS6316837B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called closed type magnetic disk device, which is a magnetic disk device housed in a closed container.

In general, this type of sealed magnetic disk device houses the magnetic disk device including the magnetic disk, magnetic head, magnetic disk drive device, etc. in a sealed container, and is kept at high temperature in a clean atmosphere that prevents the intrusion of dust from the outside. The sealed container described above not only prevents dust from entering from the outside, but also has the function of maintaining an equilibrium between the air pressure inside and outside the container. There is a need.

Therefore, changes in the air pressure inside and outside the sealed container may occur rapidly or slowly; in the former case, changes occur when the magnetic disk starts rotating and when it stops. The latter case is likely to occur not only when the temperature rises due to heat generated by each component of the magnetic disk device, when air expands and contracts due to cooling, but also when atmospheric pressure changes due to weather changes.

In this way, when the pressure difference between the inside of the sealed container containing the magnetic disk device and the outside becomes large,
When the magnetic disk rotates, the magnetic head may not be able to levitate stably from the magnetic disk, or
Alternatively, because lubricating oil is likely to enter from the spindle of the magnetic disk drive device, conventional closed magnetic disk drives of this type are equipped with a pressure balance device in the closed container to balance the air pressure inside and outside. has been done.

Such a pressure equalization device is, for example, provided with a relatively small through hole that penetrates the inside and outside of a part of the wall of a closed container, and a filter is installed in this through hole to filter out dust contained in the outside air flowing through the hole. The one that is attached is often used. however,
In such a pressure balancing device, if the thickness of the filter is increased in order to increase the dust filtration effect of the filter, the air resistance passing through the filter will significantly increase, so as mentioned above, the air pressure inside and outside the closed container will be reduced. If a sudden change occurs, it becomes impossible to follow this change and rapidly balance the air pressure inside and outside the closed container. Therefore, in the above-mentioned conventional pressure equalization device, a thin filter with low air resistance is used to improve air circulation, so dust easily enters the inside of the closed container. There is a drawback that it can cause malfunctions such as crashes of the magnetic head.

This invention has been made with attention to this point, and is applicable not only when the pressure changes inside and outside the sealed container that houses the magnetic disk device occur slowly, but also when the pressure changes inside and outside the sealed container suddenly change. However, in response to this, we would like to provide a sealed magnetic disk device that has a pressure balancing device that not only can rapidly balance the pressure inside and outside the sealed container, but also has an excellent dust filtration effect. That is.

That is, both FIGS. 1 and 2 show an embodiment of the present invention, with FIG. 1 being a front view of a sealed magnetic disk device showing a section of a sealed container, and FIG. 2 showing a pressure equalization device. In this diagram, 1 is a closed container, 2 is a pressure equalization device, 3 is a drive motor that rotates a spindle 4 at a predetermined speed via a belt 5, and the spindle 4 has a bearing on the bottom plate of the closed container 1. 6, and a magnetic disk 10 is removably mounted thereon. 7 is the inside of the sealed container 1 and the pressure equalization device 2
The inner end of the communicating tube 7 on the closed container 1 side extends to the vicinity of the spindle 4 and the bearing 6. 8 is a container 2a of the above-mentioned pressure equalization device 2
12 is a magnetic head drive device for moving the magnetic head 11 corresponding to the magnetic disk 10 to a target track;
Reference numeral 3 has one end fixed to one side wall in the container 2a of the pressure equalization device 2, and is expanded by the pressurized air in the closed container 1 flowing from the communication pipe 7 protruding into the container 2a, and is a return spring to be described later. A bag body made of a bellows etc. which is contracted by a body 14, 14 is this bag body 13
9 is a return spring body made of a metal coil spring or the like, which is stretched between the free end of the container 2a and the other side wall of the container 2a, and expands or contracts the bag body 13 and holds it at a predetermined length; This filter is attached to a communication hole that communicates the inside of the body 13 with outside air, and the filter 9 used is one that has relatively high air resistance but has an extremely good dust filtering effect.

The pressure balance device in the sealed magnetic disk device of the present invention is constructed as described above, and FIG. It shows. Now, when the spindle 4 of the stopped magnetic disk device starts to rotate, the air pressure in the closed container 1, especially in the vicinity of the spindle 4, drops rapidly, but the air inside the bag 13 of the pressure equalization device 2 flows into the communication pipe 7. Since it is rapidly sucked into the closed container 1 through the airtight container 1, the air pressure inside and outside the closed container 1 can be balanced. In this way, the air inside the bag body 13 is transferred to the airtight container 1.
As a result, the bag body 13 contracts against the pulling force of the return spring body 14 as shown in FIG. Once reached, the bag 13 begins to expand due to the return tension of the return spring 14, and returns to the state shown in FIG. 2A at a low speed while sucking outside air through the filter 9.

Next, when the spindle 4 of the magnetic disk device that had been rotating steadily begins to stop, the air pressure in the sealed container 1, especially near the spindle 4, rises rapidly, but the pressurized air is passed through the communication pipe 7. As shown in FIG. 2C, the air flows into the bag 13,
The air pressure inside and outside the closed container 1 can be balanced by further expansion from the state shown in FIG. 2A. Then, when the spindle 4 completely stops, the bag body 13
2C due to the return pressing force of the return spring body 14.
The state shown in FIG. 2 returns to the state shown in FIG. 2A at a low speed.

The above explanation describes the operation when a sudden change in the pressure inside and outside the sealed container 1 that houses the magnetic disk device occurs.However, when the pressure change inside and outside the sealed container 1 occurs slowly Since outside air is sucked into the closed container 1 through the communication pipe 7 and the filter 9 at a low speed, or is discharged,
There is no problem even if the air hole of the filter 9 is made large in order to increase the dust filtration effect.

As described above, the sealed magnetic disk device of the present invention can be used not only when pressure changes occur slowly inside and outside the sealed container housing the magnetic disk device, but also when pressure changes occur rapidly inside and outside the sealed container. In response to this, not only can the air pressure inside and outside the sealed container be rapidly balanced, but it also has an excellent dust filtration effect, preventing the generation of pressure differences between the inside and outside of the sealed container, and eliminating dust. It is possible to prevent various malfunctions caused by infiltration,
This significantly contributes to improving the reliability of sealed magnetic disk drives.

In addition, in one embodiment mentioned above, the bag body 13
We described the case using bellows as
Not only can the same effect be obtained by using something like the diaphragm of the bag that expands and contracts, but also the case where a metal coil spring is used for the return spring body 14 has been described, but if the bag body 13 itself has elastic force. Needless to say, the same effect can be obtained even if the bag body 13 is expanded by its own returning force.

[Brief explanation of the drawing]

Each figure shows an embodiment of this invention.
FIG. 1 is a front view of a sealed magnetic disk device showing a closed container in cross section, and FIG. 2 is a cross-sectional view illustrating the operation of the pressure equalization device. In the drawing, 1 is a closed container, 2 is a pressure balance device, 2
a is a container, 3 is a drive motor, 4 is a spindle, 7
is a communication pipe, 8 is an outside air distribution pipe, 9 is a filter, 10
1 is a magnetic disk, 11 is a magnetic head, 12 is a magnetic head drive device, 13 is a bag body, and 14 is a return spring body. Note that the same reference numerals in the figures indicate the same parts.

Claims (1)

[Scope of Claims] 1. In a sealed magnetic disk device having a pressure balancing device connected to the outside of the sealed magnetic disk device via a communication pipe, the pressure balancing device includes a container for protecting the internal structure and a container for protecting the internal structure. The bag body has an air circulation port to keep the air pressure and the outside pressure in equilibrium, a bag body made of a stretchable material, and an air circulation port equipped with a dustproof filter to adjust the air pressure inside the bag and the outside pressure. is fixed to one side wall in the container of the air balance device, and
A closed magnetic disk device characterized in that an inner end on the side of the closed container of a communication pipe connecting a pressure equalization device and a closed container of the magnetic disk device is extended to a position close to a spindle and a bearing. 2. The closed type according to claim 1, characterized in that a return spring body is added between one end of the bag made of a stretchable material of the pressure equalization device and the inner wall of the container for protecting the internal structure. Magnetic disk device.