JPS6225706Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to an adsorption force measuring device, and more particularly to a magnetic disk adsorption force measuring device that measures the amount of lubricant applied to a magnetic disk by the magnitude of the adsorption force. The magnetic disk used in magnetic disk devices has a laminated structure with a magnetic thin film coated on the substrate surface.The magnetic head floats during high-speed rotation, but when the rotation starts or stops, it slides into contact (contact, start, etc.). It is necessary to apply lubricant to protect the magnetic thin film and ensure its durability. Generally, the greater the amount of lubricant applied, the better the durability of the magnetic thin film, but if it is excessive, it will remain on the surface of the magnetic thin film and generate adsorption force. Generally, the thickness of the magnetic film applied to a disc is not uniform from the inner circumference to the outer circumference. Therefore, if the lubricant is applied evenly to the film surface, the lubricant will not be completely absorbed into the film. There are some places where it is impregnated and other places where it becomes saturated and remains on the film surface, which causes an adsorption phenomenon with the magnetic head to occur in some places. Therefore, the amount of lubricant impregnated has been determined by measuring the adsorption force of predetermined parts of the magnetic disk (for example, the outer periphery, the inner periphery, and the intermediate part between the outer periphery and the inner periphery). The conventional measurement method is to place the head in pressure contact with a magnetic disc coated with lubricant, leave it for about 24 hours, and then
The adsorption force was measured by sliding the head on the disk surface and measuring the tension at the moment it began to slide, or by applying rotational force to the disk and measuring the torque at the moment it began to rotate. The first method, that is, the method of fixing a disk and sliding the head, involves arranging a large number of heads in the radial direction to measure the inner and outer circumferences of the disk, and sequentially measuring the adsorption force with the heads. This requires time and effort, and has the disadvantage that measured values cannot be trusted due to variations due to changes in measurement conditions, and the suction force per head is minute. In addition, in the second method described above, in which multiple heads are arranged and fixed on the entire surface of the disk and the disk is rotated, the total adsorption force of all the heads is measured, and the adsorption force for each predetermined part is the average. The value was measured, which caused an inconvenience that did not suit the original purpose of measurement. The purpose of the present invention is to provide a measuring device that can accurately and easily measure the suction force at the radial position of a disk without changing the measurement conditions. The force measurement device is an attraction force measurement device that measures the attraction force of a magnetic disk coated with lubricant. a support device having a structure in which the arm is rotatably mounted around a rotationally immovable support such that each of the protrusions draws a concentric circle within the same plane; and a support device that is connected to each arm that constitutes the support device. a plurality of torque detectors for measuring torque, the magnetic disk is fixed to the rotating column in a state of pressure contact with the protrusion of the support device, and each of the torque detectors measures a predetermined circumference of the magnetic disk. This is an adsorption force measuring device configured to measure the limit torque that causes the arm to rotate at a certain position, and the details will be clarified in the explanation using figures. FIG. 1 is a schematic diagram of a magnetic disk, in which a is a top view and b is a side sectional view. In the figure, 10
11 is a magnetic disk, 11 is a substrate of the disk, 12 is a magnetic thin film, and 13 is a center hole of the magnetic disk 10. The magnetic thin film 12 is coated with a lubricant and impregnated therein. FIG. 2 is an embodiment of the present invention, and is a schematic side sectional view of the main parts of the suction force measuring device. In the figure, 1 is a rotating column that supports and fixes the magnetic disk 10;
2 is an arm; 3 is a protrusion with a spring 4 at its base; 5 is a bearing for rotating the arm 2 around the rotating support 1; 6 is a torque detector; and 7 is a hanger for connecting the torque detector 6. , the arrangement of the armrest 2 (i.e.,
The arrangement of n protrusions is arranged radially at different radial lengths, and the magnetic disk 10 is attached to the rotating support 1, and after being left for about 24 hours, the torque detector 6 connected to the hanger 7 is connected to the magnetic disk 10. Therefore, the protrusion 3 of the magnetic disc 10
Measure the suction force at the place where it is pressed. The torque detector 6 is, for example, a spring scale, which pulls the hanger 7 and measures the torque at the moment the arm 2 starts rotating. Let the measured torque value be F, the distance between the bearing 5 and the hanger 7 be l, the length of the arm between the bearing 5 and the protrusion 3 be L, the number of protrusions 3 be n, and the rolling friction force of the bearing 5 be F'. For example, the adsorption force f per protrusion 3 is calculated as f=1/n・l/L・(F−F′), but even if this formula is not used, it is possible to measure the disk properly coated with lubricant. If the value and measurement conditions match, the measured torque value F
can be substituted. As a reference example, actual measurement results of adsorption force using the conventional method and this embodiment are shown. The measurement conditions are as follows: The condition of the applied lubricant depends only on temperature and humidity, so the head was pressed against the disk (10gr pressure) at a constant temperature and humidity of 40℃ and 50%, and the measurement was performed after leaving it for 24 hours. did. Two disks were used, A and B.
In Method 1, the same part was measured three times each.

[Table] As shown in the table above, method 1 is a measurement value obtained by fixing the disk and moving the head, which is time-consuming and has a large variation, whereas method 2 is a measurement value obtained by fixing the disk and rotating the disk. Although the measured values are good, they cannot be trusted as they are average values.
According to the measurement results according to this embodiment, it was found that a strong adsorption force appeared on the inner peripheral portion of the disk B, and the effect of the measuring device according to this embodiment is clear. According to the present invention, the amount of lubricant applied to a magnetic disc can be easily and accurately measured at any location on the disc.

[Brief explanation of the drawing]

1 is a magnetic disk, a is a top view, b is a side sectional view, and FIG. 2 is a schematic side sectional view of a measuring device according to an embodiment of the present invention, in which 10 is a disk, 11 is a substrate, and 12 is a side sectional view. magnetic thin film, 13 is center hole, 1
is the rotating support column, 2 is the arm, 3 is the protrusion, 4 is the spring,
5 is a bearing, 6 is a torque detector, and 7 is a hanger.

Claims (1)

[Claims for Utility Model Registration] An attraction force measuring device for measuring the attraction force of a magnetic disc coated with lubricant, wherein the length of each arm is provided with a protrusion at the tip of the base of a spring. A support device having a structure in which a plurality of different armrests are rotatably mounted around an immovable rotary support such that each of the projections draws a concentric circle within the same plane; a plurality of torque detectors connected to each other to measure torque, the magnetic disc is fixed to the rotating column in a state of pressure contact with the protrusion of the support device, and each of the torque detectors is configured to measure the torque of the magnetic disc. An adsorption force measuring device configured to measure a limit torque that causes rotation of the arm at a predetermined circumferential position.