JPS6037422B2 - Durability test method for sliding discs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for testing the durability of loss-of-life disks such as magnetic disks.

Recent magnetic disk drives perform recording and reproduction by flying a magnetic head above a magnetic disk, which is a magnetic recording medium.

That is, the magnetic head aerodynamically floats due to the flow of air generated near the surface of the magnetic disk as the magnetic disk rotates. Therefore, until the magnetic disk stops rotating or does not reach the specified rotation speed,
A magnetic head is sliding in contact with the magnetic disk.

Therefore, in order to increase the durability against such vibrations, magnetic disks not only have a magnetic recording medium layer formed on a metal disk such as aluminum, but also coat and impregnate the disk with a lubricant. Now, in order to prevent important information from being destroyed due to damage to the magnetic disk, it is necessary to improve the durability of the magnetic disk as described above.

For this reason, many efforts are being made to smooth the surface of magnetic recording media, develop new lubricant compositions, and find optimal amounts of coating and impregnation.

However, no method has been developed that is highly reproducible and can determine the durability of magnetic disks in a short period of time. For example, in quality tests, it is necessary to conduct long-term continuous operation tests using actual magnetic heads. There was the inconvenience of not being able to get it.

Another possibility is to have a hard ball slide on a magnetic disk instead of a magnetic head, but experiments have shown that this method has low reproducibility.

It is assumed that this is caused by the strong influence of minute protrusions scattered on the magnetic disk. Furthermore, when applying a large external load to the magnetic head and making it move on the magnetic disk, it is not only limited by the strength of the magnetic disk itself, but also requires a significantly large driving force to rotate the magnetic disk. There are issues that require it, so it will never come to fruition. The purpose of the present invention is to easily, quickly, and reproducibly test the durability of magnetic disks without such problems. A dowel that is configured to be movable along a plane and swingable in a plane perpendicular to the disc surface, and a cylindrical-shaped dowel at the bottom of the dowel, and a test object. Using a testing device equipped with a chip whose maximum axis is oriented in the radial direction of the disc, the weight of the heavy key is brought into line contact with the disc to be tested, and a load perpendicular to the chip is applied to the chip and the disc to be tested. The disk to be tested is rotated while monitoring the sliding frictional force generated between it and the test disk, and from the time when the chip and the disk to be tested start to lose movement until the time when the sliding frictional force starts to increase rapidly. This is achieved by measuring the amount of sliding and verifying the durability of the disk under test based on this measured value.An example of this will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing an example of an apparatus for conducting a test according to the present invention, FIG. 2 is a diagram showing friction force fluctuations to explain measured values, and FIG. 3 is a diagram showing measured values according to the present invention. FIG. 3 is a diagram showing the relationship with durability in actual usage conditions.

In Fig. 1, 1 is a cylindrical tip made of hard material such as wear-resistant carbon steel, ceramic, or ferrite, 2 is a weight, 3 is a pivot bearing, 4 is a yoke, and 5
A sandwich guide, 6 a swing arm, 7 a pivot, 8 a support frame, 9 a link, 1 a river friction force detector, and 11 a disk to be tested.

The chip 1 is bonded to a weight 2, and the weight 2 is connected to a yoke 4 via a pivot bearing 3 so as to be rotatable around an axis perpendicular to the longitudinal direction of the chip.

Further, the yoke 4 is restricted by the pinch guide 5 so that the chip 1 does not rotate, but is movable in the vertical direction. Then, the movement of the yoke 4 in the direction of arrow A is transmitted to the swing arm 6 by the pin 4a provided at the upper end of the yoke 4, and the movement of the swing arm 6 is further transmitted to the swing arm 6 so as to push the link 9 and operate the detector 10. It has become. It is assumed that the support frame 8 and the detector 1 are both fixed.
Due to this structure, the chip is pressed against the test disk 11 with a load equal to the sum of its own weight and the weights of the weight 2 and the yoke 4.

Furthermore, since the pivot bearing 3 is provided, the load is evenly distributed over the longitudinal direction of the chip 1. Furthermore, the tip 1 is oriented in a fixed direction (radial direction of the disk 11) by the pinch guide 5 with an error within the range of a minute swing angle of the sardine arm. When the disk under test 11 rotates in the direction of arrow A in this state, a frictional force in the direction of arrow A is applied to the chip 1, and the frictional force is applied to the pin 4a, the swinging arm 6,
The detector is activated via link 9 and its size is detected. Figure 2 shows the change in the frictional force detected as described above over time. As shown in the figure, the frictional force is detected at the same time as sliding starts, and from then on, its value remains almost constant. Although the value is maintained, a phenomenon occurs in which the frictional force starts to increase rapidly.

In other words, when this phenomenon occurs, it is no longer possible to maintain a smooth sliding state, and it means that the lubrication ability of the emotional disk has been lost. Therefore, in the present invention, the durability of the hyperdynamic disk is determined by the elapsed time TR from the start of sliding until this phenomenon occurs. To give an example of an experiment, the material of the chip is SK material and the dimensions? 2 sides, length 4 sides, weight 1 omitted, and rotational speed of the sliding disk 120 pm, the magnetic coating film will not be overly phosphorous for 1 minute if the disk absorbs less lubricant. Durability of 15 minutes for a disc and 120 minutes or more for a normal disc (this is tentatively referred to as roller strength).

). Then, a series of experiments such as this and a number of experiments to obtain a quantity indicating durability under actual usage conditions were conducted in parallel and the following results were obtained. That is, as shown in Fig. 3, the maximum number of times that normal frictional contact between the magnetic disk and the magnetic head is possible (CSS number) is taken as the axis, and the test value (roller strength) according to the present invention is taken as the vertical axis, and the difference between the two is taken as the axis. Looking at the correlation, there was a nearly linear proportional relationship, and the reproducibility was also good.

In this way, in the present invention, since the test tip contacts the sliding disc in a straight line, the influence of local unevenness on the sliding disc surface is eliminated, and measurement values with good reproducibility are obtained. be able to.

In addition, since the contact area is small, it is possible to apply a large contact pressure with a relatively small load and perform a test at high acceleration. In this case, the test can be easily performed because the motor that rotates the disk does not require a large torque.

In the above embodiment, a cylindrical tip was used, but the present invention is not limited to this, and it is obvious that other shapes may be used. It is also possible to use the sliding distance.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of an apparatus for carrying out the present invention, FIG. 2 is a diagram showing the relationship between changes in frictional force over time and measured values of the present invention, and FIG. FIG. 3 is a diagram showing the correspondence between measured values of the present invention and durability under actual use conditions. 1... Chip, 2... Weight, 3... Pivot bearing, 4...
Yoke, 5...pinching guide, 6...swinging arm, 7.
... Pivot, 8... Support frame, 9... Link, 10... Detector, 11... Disc under test. Shu 1 picture, younger brother Z picture, Shu 3 picture

Claims (1)

[Claims] 1. A chip formed in a cylindrical shape and having a long axis oriented in the radial direction of the disc to be tested is brought into line contact with the disc to be tested, and a load is applied to the chip in a direction perpendicular to the disc to be tested. The disk under test is rotated while monitoring the sliding friction force generated between the chip and the test disk, and from the time when the chip and the disk under test start sliding, the sliding friction is increased. A method for testing the durability of a sliding disk, characterized by measuring the amount of sliding at the point when the force starts to increase rapidly, and verifying the durability of the disk under test based on this measured value.