JPS5816259B2 - Jikiday squat couch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk drive in which fixed magnetic heads of a contact start/stop type are arranged in a multi-track configuration.

As the name suggests, the contact start/stop method refers to a method in which the slider surface of the magnetic head is in contact with the magnetic disk when stopped, and is separated from the magnetic disk by a small gap during operation.

The advantage is that the structure of the magnetic head is extremely simple.

Therefore, it is clear that when the magnetic disk rotates at low speed, there is a sliding contact between the magnetic disk surface and the slider surface.

Furthermore, as magnetic recording technology improves, in order to achieve high-density recording, the gap between the magnetic disk and the slider, ie, the so-called flying height, is often set to a minute value of about 0.3 μm.

Under the above-mentioned background, what is required for the slider flying scene of a magnetic head is good surface roughness as well as wear resistance of the magnetic disk.

In terms of surface roughness, both the magnetic disk surface and the slider floating surface are finished to a value of Rmax O.01 to 0.02 μm or less.

Here, as seen in the case of block gauges, for example, the better the surfaces that come into contact with each other, the more remarkable the phenomenon of close contact between the two becomes.

Incidentally, in the case of block gauges, the adhesion phenomenon is said to be due to the surface tension of the extremely thin oil film interposed between the two.

It was confirmed that a very similar phenomenon occurs at the contact surface between the magnetic disk and the slider.

The increase in adhesion between the magnetic disk and the slider means that
The tangential pulling force of the contact surfaces will also be increased, which means that the starting torque of the device motor will be increased.

Therefore, when magnetic heads are arranged in a multi-track configuration like in a magnetic disk device, the slider surface that is in contact with the magnetic disk also becomes wider overall, and the adhesion force becomes so great that sometimes the device motor does not start. It ends up.

After investigating this phenomenon in detail, it was found that the increase in starting torque of the device motor is closely related to the relative humidity inside the device.

In other words, it was found that when the relative humidity is high, the starting torque increases significantly.

It is presumed that this is because a liquid film generated by adsorbed vapor on the magnetic disk surface or vapor in the atmosphere accumulates between the contact surfaces and plays a role similar to an oil film in a block gauge.

Fig. 1 shows the actual measured value of the starting torque after being left for a certain period of time under a certain relative humidity.

As is clear from this figure, the relative humidity inside the device is 30%.
It was found that the starting torque does not increase if it is held below.

Hitherto, there has been no closed-type device of this type that has been designed to actively lower the relative humidity, and has not provided protection against increased adhesion between the magnetic disk and the slider.

The present invention is characterized in that the magnetic disk device has a sealed structure, and is prefilled with low-humidity nitrogen gas in order to maintain the relative humidity inside the device at 30 parts or less.The purpose of this is to ensure close contact between the magnetic disk and the slider. The goal is not to generate a liquid film that would strengthen the force.

Next, the sealed structure and the filling of low-humidity nitrogen gas according to the present invention will be described with reference to specific examples.

FIG. 2 shows an embodiment of the present invention, in which 1 is a magnetic disk;
2 is a magnetic head assembly.

The magnetic head assembly 2 refers to a magnetic head assembled on a plate, and as shown in the figure, it faces the upper and lower surfaces of a magnetic disk and consists of a device 1 on the circumference.

This magnetic disk device is equipped with inflow and outflow holes, and by using both of these holes, it is possible to flow and circulate low-humidity nitrogen gas into the device.

When filling the apparatus with low-humidity nitrogen gas, a cover 10.11 for the inflow/outflow hole is provided at the inflow/outflow hole using the same means as the plate of the magnetic head assembly.

In addition, the inside of the device is filled with low-humidity nitrogen gas 12, and an O-ring is interposed at the joints when assembling the device, especially in order to ensure a sealed structure.

Specifically, there is a housing O-ring 8 between the upper housing 3 and the lower housing 4, and a plate 0 for fixing the plate of the magnetic head assembly 2 and the inlet/outlet hole cover 10.11 to the housing. A motor O-ring 9 is interposed between the ring 7 and the joint between the motor and the housing.

The 01J ring for the motor is intended to be concerned about the fact that the vicinity of the magnetic disk and the vicinity of the motor are connected through the bearing in the shaft case 6.

In this way, we ensure that the entire device is completely sealed.

In addition to the features of the magnetic disk drive according to the present invention as described above, the magnetic head assembly 2 is structurally mounted from the outside of the housing via the 01J ring, so that the magnetic head assembly can be removed and replaced extremely easily. It is characterized by

Of course, it is not outside the scope of the present invention to enclose low-humidity air in such a sealed magnetic disk device.

However, to obtain low-humidity air, a high-performance dehumidifier is required.

In the case of nitrogen gas with point image humidity, it can be easily obtained without using any dehumidifier.

That is, so-called commercially available nitrogen gas, especially if it is of high purity, is already packed in containers such as cylinders in an extremely low-humidity form.

Therefore, by piping from such a container to the inflow hole via a dust removal filter, clean, low-humidity nitrogen gas can be easily fed into the apparatus.

It has also been experimentally confirmed that the levitation characteristics of a magnetic head in a nitrogen gas atmosphere are not much different from those in air.

As explained above, in a magnetic disk device with a sealed structure, in order to keep the relative humidity inside the device as low as possible, specifically at 30% or less, it is easy to fill it with low-humidity nitrogen gas in advance. Moreover, in terms of structure, it fully satisfies the function of a closed type by using O-rings at device joints, etc.

Furthermore, the effects of the present invention can be applied not only to magnetic disk drives with fixed heads, but also to magnetic disk drives with built-in moving heads.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the time the magnetic disk device is left and the starting torque required to start the magnetic disk when the magnetic disk device is left under a constant relative humidity, and FIG. FIG. 2 is a vertical cross-sectional view showing one embodiment of the invention. 1 is a magnetic disk, 2 is a magnetic head assembly, 3 is an upper housing, 4 is a lower housing, 5 is a motor, 6 is a shaft case, 7 is an O-ring for a plate, 8 is an O-ring for a housing, and 9 is a motor 10 is a cover for the inlet hole, 11 is a cover for the outlet hole, and 12 is a nitrogen gas.

Claims (1)

[Claims] 1. In a magnetic disk device having a contact start/stop type magnetic head, low temperature nitrogen gas must be filled in the device in advance in order to maintain the atmosphere around the magnetic disk and magnetic head at a relative humidity of 30 parts or less. A sealed magnetic disk device featuring: