JPH0245732A - Testing device for static friction measurement - Google Patents

Abstract

PURPOSE:To take an accurate measurement by easy operation by providing a spindle whose friction coefficient is extremely small, a torque gauge with a handle which is coupled directly with the spindle, and a head which presses the surface of a medium held on the spindle. CONSTITUTION:The handle 19 of the torque gauge 13 and a pointer 20 are united and the torque gauge shaft 27 and the handle 19 are fitted through a bearing 28 whose friction coefficient is small. A scale plate 21 is fixed to the spindle 12 and the shaft 27 is fixed to the spindle 12. Further, a spring 22 for torque measurement is fitted between the handle 19 and scale plate 21 and the spring constant of the spring 22 is so adjusted by turning the handle 19 that the torque with which the spindle 12 begins to rotate is measured. Then, when the friction coefficient is measured, the handle 19 is rotated slowly over a look at the pointer 20 and the value on the scale plate 21 when the spindle 12 begins to rotate is read to accurately find the torque. The friction coefficient of the medium is accurately found from the torque.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a tester for measuring static friction that tests the attraction and static friction of a magnetic disk medium, and provides a tester that enables more accurate measurements in a shorter time through hourly operation. TECHNICAL FIELD The present invention relates to a static friction measuring tester for testing the attraction and static friction of a magnetic disk medium.

In recent years, magnetic disk drives have been required to have higher recording densities, and as a result, the flying height of magnetic heads has decreased, and disk media are required to have improved crash resistance.

One way to improve crush resistance is to apply lubricant to the surface of the disk medium, but if the amount of lubricant is small, it will easily crash, but if there is too much lubricant, it will stick to the head and the medium will not be able to rotate. A failure occurs.

In order to avoid these problems, it is necessary to measure the adsorption force and frictional force in order to strictly control the amount of lubricant on the surface of the medium.

[Conventional technology]

In conventional adsorption and static friction tests, Fig. 2 (a) (
The method shown in b) was used.

In FIG. 2(a), a weight 3 is attached to the head slider 2 placed on the disk medium 1, a thread 5 having a ring 4 at the tip is attached to the weight 3, and a tension scale (such as Kolefkus) 6 is attached to the ring 4.
This is a method of pulling it in the direction of the arrow in the figure. At this time, if the tensile force is F, the pressing force of the weight 2 is N, and the coefficient of friction is μ, then the formula F-μN holds true, and μ is determined from this formula.

FIG. 2(b) shows a head 9 attached to an arm 8 rotating around a fulcrum 7, which rotates the disk medium 1 at a constant low speed.
This method uses a load sensor 10 to measure the force applied to the head 9 in the circumferential direction of the medium.

Note that the disk medium 1 is rotated by a motor (not shown).

[Problem to be solved by the invention]

In the conventional method shown in Fig. 2 (a), when the weight 3 is thefted, it takes time to press the hent slider 2 evenly, and since a temporary spring is not used, it differs from the actual device state. , reliability was low.

In addition, in the method shown in FIG. 2 (b), the arm 8 is rotatable around the fulcrum 7 and the head 9 is not fixed, making it difficult to handle the tester and causing damage to (scratching) the disk medium 1 and the head 9. ) I had something to do.

Therefore, an object of the present invention is to provide a tester that enables more accurate measurements in a shorter time by simple operation.

[Means to solve the problem]

The above-mentioned problem is caused by a spindle with very low friction held on a support base 11 and a torque gauge 1 with a handle directly connected to the spindle 12, as shown in FIGS.
3 and a static friction measuring tester comprising a head 15 that presses the surface of the medium 14 placed on the spindle 12 with a predetermined pressure.

[Effect]

That is, a spindle 12 integrally formed with a torque gauge 13 with a handle is supported by a bearing 17 on a support base 11 with low friction. After setting the medium 14 on the spindle 12 through the center scoop 18 of the measuring medium 14 from the upper part of the torque gauges 13, the measuring spoon 15 attached to the coupling 16 is placed at the measuring position on the surface of the medium 14. have it placed. At this time, the Herad I5 presses the medium surface with a spring B in the same way as in an actual device.

Next, turn the handle 19 slowly while watching the upper needle 20, and read the torque on the scale plate 21 when the spindle 12 begins to rotate. The torque at this time is Tgr'cm,
The pressing force of the head is Ngr, the radius of the medium at the measurement point is Rca,
If the friction coefficient of the medium is μ, then T=Nxμ×R Therefore,
It can be determined from μ=T/RN.

[Embodiment] FIGS. 1A and 1B are diagrams illustrating an embodiment of the present invention.

In FIGS. 1(a) and 1(b), 11 is a support stand, 12 is a spindle, 13 is a torque gauge, 14 is a measuring medium, 1
5 is a measurement head, 16 is a mounting base, 17 is a bearing,
18 is a center hole, 19 is a handle, 2o is a pointer, 21 is a scale plate, 22 is a torque gauge spring, 23 is a medium holding ring, 24 is a head arm, 25 is a set screw, 26 is a base, 27 is a torque gauge shaft , 28 are bearings.

The handle 19 and pointer 20 of the torque gauge 13 are integrated, and the torque gauge shaft 27 and handle 19 are attached via a bearing 28 with a low coefficient of friction. The scale plate 21 is fixed to the spindle 12, and
The torque gauge shaft 27 is fixed to the spindle 12 with a set screw 25.

A torque measuring spring 22 is attached between the handle 19 and the scale plate 21, and the spring constant of the spring 22 is adjusted so that by turning the handle 19, the torque at which the spindle 12 starts to rotate can be measured. There is.

The support 11 fixed to the base 26 and the spindle 12 are connected by a ring 17 with a very small coefficient of friction, and the coefficient of friction of the spindle 12 is kept at a value so small that it can be ignored in measurements. .

The mounting base 16 on which the head arm 24 is attached is configured so that the upper and lower positions of the measuring head 15 and the radial position on the medium can be freely set.

A center hole (larger than the scale plate 21) 18 of the measuring medium 14 is passed through from above the scale plate 21 of the tester, and the medium 14 is mounted on the spindle 12. Measurement medium 14
Although it does not move on the spindle 12 due to the frictional force on the mounting surface, a medium holding ring 23 is used to further fix it. The head arm 24 is the same as the herad arm of the actual device.
The head 15 is attached to a mounting base 16, and the head 15 presses the medium surface with a spring B (same spring pressure as the spring arm of the actual device).

To measure the coefficient of friction, slowly turn the handle 19 while looking at the pointer 20, and read the value on the scale plate 21 when the spindle 12 begins to rotate, which indicates the torque (adsorption of the medium).
can be read accurately and easily. From that torque, μ−
Using T/RN, the coefficient of friction of the medium is determined.

In the example, the medium 14 and the head 15 are attached to the tester, and the pressing force N of the head 15 is set to the same IQg as the actual device.
r, the torque T was measured at 8 measurement points on the same radius using a coating medium with a large amount of fluorine-based lubricant, and the torque T was entered into the aforementioned 2 μ = T / RN to find μ. Table 1 shows the results.
Shown below. Further, Table 2 shows the results of measuring the same medium using the conventional technique [the method shown in FIG. 2 (a)].

Table 2: Conventional technology The friction coefficient roller shown in Figure 2 (a) is large.

Since it is only necessary to turn the handle 19 while looking at the pointer 20, the operation is simple and measurement can be carried out easily. Furthermore, as shown in Table 1 above, the measurement value obtained using the conventional method is one digit, but the method of the present invention can produce up to two digits, making it more accurate, and the time required for measurement is also reduced to about 1/6 compared to the conventional method. be done.

〔Effect of the invention〕

As explained above, according to the present invention, the torque gauge and the spindle are integrated, and all you have to do is turn the torque gauge while looking at the pointer of the torque gauge, which makes the operation easier and more accurate than the conventional method, and also reduces the time required for measurement. Since the time is reduced to about 1/6 of the conventional method, it will contribute to improving the reliability of the media and reducing costs.

[Brief explanation of the drawing]

FIGS. 1A and 1B are diagrams for explaining an embodiment of the present invention, and FIGS. 2A and 2B are diagrams for explaining a conventional test device for measuring static friction. In the figure, 11 is a support base, 12 is a spindle, 13 is a torque gauge, 14 is a measuring medium, 15 is a measuring head, 16 is a mounting base, 17 is a bearing, 18 is a center hole, 19 is a handle, and 20 is a pointer. , 21 is the scale plate, 22 is the spring for the torque gauge, 23 is the medium holding ring, 24 is the spatula arm, 25 is the set screw, 26 is the base, 27 is the torque gauge shaft, Wood Qg Juice Ichijiko 1 te word L4L sum m th figure (child 92) final complete θ rib - award way to strip Σ theory θ elbow figure 1!1 (Y.l) Edo/V Shizuka/? Figure 2

Claims (1)

[Claims] A spindle (12) with very low friction held on a support base (11), a torque gauge (13) with a handle directly connected to the spindle (12), and a torque gauge (13) held on the spindle (12). A test device for measuring static friction consisting of a head (15) that presses the surface of a medium (14) with a predetermined pressure.