JPH02254617A - Method and device for measuring friction degree - Google Patents

Abstract

PURPOSE:To easily and correctly measure a friction degree between a magnetic head and a magnetic disk by measuring a heat quantity change transmitted to the magnetic head with a contact as the temperature change, and deciding the friction degree based on the secular change of a measured temperature. CONSTITUTION:Thin film temperature sensors 7 and 7a having a Hall element 11 in which an output voltage is changed according to a circumferential temperature in a fixed magnetic field, extension lines 12, 13 and 19 to impress a current to the Hall element 11, a coil 14 to generate a magnetic field with the extension lines 12, 13 and 19 to measure the output voltage of the Hall element 11, a magnetic substance 15 to conduct the magnetic field 14 to the Hall element 11, and a substrate 16 are provided to a slider edge surface 2 of the magnetic head. In such a case, the friction heat of the magnetic head and magnetic disk is transmitted to the slider 2 of the magnetic head, the change quantity of the heat quantity is measured as the temperature change by using the thin film temperature sensors 7 and 7a, and the friction degree of the magnetic head is decided. Thus, the friction degree between the magnetic head and magnetic disk can be correctly measured.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention is directed to a contact start/stop type magnetic recording device, in which a magnetic head is generated by contact with a magnetic disk at the time of starting and stopping rotation of a magnetic disk. The present invention relates to a method and apparatus for measuring the degree of friction of.

(B) Prior art When manufacturing a magnetic head, the degree of friction between the magnetic head and the magnetic disk, or friction characteristics (a broad concept that includes the coefficient of friction, hereinafter referred to as FZ friction 6) is important.

The conventional method of measuring the degree of friction between the magnetic throat and the magnetic disk uses a piezoelectric element to calculate F? from the relationship between the output voltage and the degree of friction. ! There is a method to measure the degree of friction. (
C, E, Yeack-3cranton, IEEE
Transon Magn, Vol, MAG-22, N
o, 5. PP, 1011.1986), a piezoelectric element is an element that converts strain into voltage using a piezoelectric effect (piezo effect) in which an ionic crystal generates electrical decentralization in response to stress caused by an external force.

FIG. 14 shows an example of a conventional device for measuring the degree of friction using a piezoelectric element 1. In this device, the piezoelectric element 1 is attached to a slider 2 of a magnetic head, and the slider 2 is supported by a suspension 3. .

When the magnetic head and magnetic disk come into contact, the distortion of the suspension 3 is caused by the piezoelectric element 1'? :Convert to voltage and measure the degree of friction.

FIG. 15 shows another example of a conventional device for measuring the degree of friction using the piezoelectric element 1. As shown in FIG. In this device, a piezoelectric element 1 is attached to a suspension 3 that supports a slider 2 of a magnetic head.

When the magnetic head and the magnetic disk come into contact, the distortion of the suspension 3 is converted into voltage by the piezoelectric element 1,
Measure the degree of friction.

FIG. 16 shows another example of a conventional device for measuring the degree of friction using a strain gauge 4.5. In this device, strain gauge 4
．． 5 is attached to a force detection block 6 that supports the base of the suspension 3 to which the slider 2 of the magnetic head is attached. A strain gauge 4 measures the force applied in the Z direction when the magnetic head contacts the 6 m magnetic disk, and a strain gauge 5 measures the force applied in the X direction.

As yet another example of the conventional method, using strain gauges,
There is a method of measuring the degree of friction based on the relationship between the amount of change in resistance value and the degree of friction (Jiki, Nagaya, Miyazaki, Abstracts of the 11th Academic Conference of the Japanese Society of Applied Magnetics, PP, 151987).

On the other hand, a typical example of a conventional temperature sensor is a thermocouple. Thermocouples make use of the Seebeck effect, in which current flows when a temperature difference is created between the two ends by electrically connecting the ends of two types of metal conductors to create a closed circuit and heating only one end. .

In reality, the electromotive force is measured and the temperature is determined from the relationship between the temperature and the electromotive force.

In the conventional F@friction measurement method, vibrations from the spindle motor that rotates the magnetic disk and vibrations from the surroundings where the measuring device is installed create noise, making it impossible to measure accurately. Furthermore, the zero point fluctuates due to transient temperature changes due to frictional heat between the magnetic head and the magnetic disk.

On the other hand, in conventional thermocouples, the sensor portion has a large heat capacity, which affects the temperature measurement of the magnetic head, and the positional resolution is poor.

(c) Problems to be Solved by the Invention An object to be solved by the present invention is to provide a method and apparatus that can easily and accurately measure the degree of friction between a magnetic head and a magnetic disk.

(d) Means for Solving the Problems The method for measuring the degree of friction of the present invention is based on the method of measuring the degree of friction of a contact start-stop type magnetic recording device, in which the magnetic head is generated when the magnetic head comes into contact with the cough disk when the magnetic disk rotation is started and stopped. In this method for measuring the degree of friction, the above-mentioned problem is solved by measuring the change in heat FJk transmitted to the magnetic head due to the contact, and determining the degree of friction based on the change over time in the measured temperature.

The friction measuring device of the present invention includes a Hall element whose output voltage changes depending on the ambient temperature in a constant magnetic field, a lead wire that applies a current to the Hall element, a lead wire that measures the output voltage of the Hall element, and a magnetic field. a coil that generates a magnetic field, a magnetic body that induces the magnetic field to the Hall element, and a substrate;
The above problem is solved by providing a thin film temperature sensor having an insulating film on the end face of the slider of the magnetic head.

Furthermore, the friction measuring device of the present invention includes a magnetic field resistance element whose resistance value changes depending on the ambient temperature in hot water, a lead wire for applying a current to the magnetic resistance element and measuring an output voltage, and a magnetic field resistance element whose resistance value changes depending on the ambient temperature in hot water. The above problem can also be solved by a means in which a thin film temperature sensor having a coil that generates a magnetic field, a magnetic body that induces the magnetic field to the magnetoresistive element, a substrate, and an insulating film is provided on the end face of a slider of a 61 atmosphere head. are doing.

(e) Effect The method of the present invention provides V! between the magnetic head and the magnetic disk! Frictional heat is transmitted to the slider of the magnetic head, and the amount of change in the amount of heat is measured as a temperature change using a thin film temperature sensor.The degree of friction of the magnetic head is determined from the relationship between the temperature change and the degree of friction, which has been determined in advance. do.

Therefore, mechanical distortion and vibration have no effect on the measurement method of the present invention.

Thin film temperature sensors are created based on the phenomenon that the output voltage of a Hall element changes depending on the ambient temperature when a constant current is applied in a constant magnetic field (Figure 4). Another thin film temperature sensor is also constructed based on the phenomenon that the output voltage of a magnetoresistive element changes in a constant magnetic field depending on the ambient temperature (FIG. 5). A thin film temperature sensor can be completed by creating a Hall element or a magnetoresistive element using conventional thin film forming technology, and creating a structure that applies a constant magnetic field to these elements.

(f) Examples Examples of the friction measuring method and apparatus of the present invention will be described with reference to the drawings.

The method for measuring the degree of friction of the present invention is a method for measuring the degree of friction of the magnetic head caused by contact between the magnetic head and the disk when the rotation of the magnetic disk starts and stops in a contact start-stop type magnetic recording device. The method is
The temperature is measured by the change in the amount of heat transmitted to the magnetic head due to contact,
The PJ friction degree is determined based on the change in measured temperature over time.

Figure 1 shows when the magnetic disk stops rotating (when time is 0 seconds,
3 shows the temperature change of the magnetic head when the magnetic head contacts the magnetic disk and the rotation of the magnetic disk stops after 20 seconds. The amount of heat generated by the friction of the magnetic head with the magnetic disk varies depending on the coefficient of dynamic friction, the flying height of the magnetic head, the rotation stop time, the shape and posture of the head, and other factors.

Temperature changes over time vary depending on the material of the magnetic head, the film structure of the magnetic disk, and its material.

Examples of the measuring method of the present invention for generally measuring the degree of friction are shown below. The first example is a method of evaluating using ΔTmax in FIG. The degree of friction is expressed as follows (112). In the case of Fig. 1, L=11.

M, -ΔTmax --- (1) The second example is a method of evaluation based on the area of the shaded part in FIG. The degree of friction -2 is represented by (2) 2. In the case of Figure 2, M,
-233.

g-233 The third example is a method of evaluation based on the area of the shaded area in FIG. The degree of friction H1 is expressed as (3) 2. In the case of FIG. 3, it is M3-207. Here, tISt is the time when the amount of temperature change ΔT during temperature rise and fall becomes ΔTmax (e: base of natural logarithm)? ! 2-
207 As shown in FIGS. 6 and 7, the friction measuring device of the present invention includes a Hall element ti whose output voltage changes depending on the ambient temperature in a constant magnetic field, and a drawn cotton 12 that applies a current to the Hall element 11. , a lead wire 13 for measuring the output voltage of the Hall element 11, a coil 14 for generating a magnetic field, and a magnetic 1
1N5! which has a magnetic body 15 that induces & to the Hall element 11, a substrate 16, and an insulating film 17! The temperature sensor 7 is provided on the end face of the slider 2 of the magnetic head.

FIG. 7 shows the principle of the thin film temperature sensor 7 using the Hall element 11, and FIG. 8 shows the thin film temperature sensor 7 using the Hall element 11. An example of the A degree sensor 7 is shown. FIG. 9 is a longitudinal sectional view taken along the line IX--IX in FIG. 8.

As shown in FIGS. 6 and 8, terminals 121 and 131 of the lead wires 12 and 13 of the thin film temperature sensor 7 and a terminal 141 of the coil 14 appear on the end surface of the slider 2.

FIG. 10 shows another embodiment of the FJ friction' measurement device of the present invention. This device includes a magnetoresistive element 21 whose resistance value changes depending on the ambient temperature in a constant magnetic field, and a current applied to the magnetoresistive element 21. A lead wire 19 for applying voltage and measuring an output voltage, a coil 14 for generating a magnetic field, and a magnetoresistive element 21 for generating a magnetic field.
The magnetic material 15, the substrate 16, and the insulator li! 17
A thin film temperature sensor 7a having the following structure is provided on the end face of the slider 2 of the magnetic head.

FIG. 11 shows the principle of the IwA temperature sensor 7a using the magnetoresistive element 21, FIG. 12 shows its 'ifJ, and an embodiment of the film temperature sensor 7a, and FIG. 13 shows the xm-
It is a longitudinal cross-sectional view seen from the xm line.

As shown in FIGS. 10 and 12, the terminal 1911 of the lead wire 19 of the IM temperature sensor 7a, the terminal 1 of the coil 14
41 appears on the end face of the slider 2.

(g) Effects According to the present invention, the degree of friction between a magnetic head and a magnetic disk can be accurately measured using a simple method and device.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory diagrams showing various methods of displaying the degree of friction based on the method of the present invention, and FIGS. 4 and 5 are graphs showing the characteristics of the thin film temperature sensor used in the method of the present invention. FIG. 6 is a perspective view of the friction measuring device of the present invention. FIG. 7 is an explanatory diagram showing the principle of a thin film temperature sensor using a Hall element. FIG. 8 is a perspective view of an actual thin film temperature sensor. Figure 9 is the 8th
A vertical cross-sectional view taken from the line ■-■ in the figure, FIG. 10 is another P9 of the present invention! FIG. 11 is an explanatory diagram showing the principle of a magnetoresistive element, and FIG. 12 is a perspective view of another actual thin film temperature sensor. FIG. 13 is a longitudinal sectional view taken along the line xm-xm in FIG. 12. FIG. 14 to FIG. 16 are perspective views of various conventional friction measuring devices. 1: Viezo piezoelectric element, 2 Nislider. 3; Susbensilane, 4.54 strain gauge. 7.7a: Thin film temperature sensor 511: Hall element. 12, 13.197 lead wire, 14: coil. 15: Body wash, 16: Substrate. 17: Insulating film 2 21: Magnetoresistive element 121.1
31.141.191! terminal. (4 other people) Figure 1 Figure 3 TpF 藺(su) τQ person-#Nrisen7g11 (m strange) Door I! I Harutomo (aC)

Claims (1)

[Scope of Claims] 1. A method for measuring the degree of friction of a magnetic head caused by contact between the magnetic head and the disk at the time of starting and stopping rotation of a magnetic disk of a contact start-stop type magnetic recording device, wherein said contact 1. A method for measuring the degree of friction of a magnetic head, characterized in that the change in the amount of heat transmitted to the magnetic head is measured by temperature, and the degree of friction is determined based on the change in measured temperature over time. 2. A Hall element whose output voltage changes depending on the ambient temperature in a constant magnetic field, a lead wire that applies a current to the Hall element, a lead wire that measures the output voltage of the Hall element, and a coil that generates a magnetic field; A friction measuring device for a magnetic head, characterized in that a thin film temperature sensor including a magnetic body for guiding a magnetic field to the Hall element, a substrate, and an insulating film is provided on an end face of a slider of the magnetic head. 3. A magnetoresistive element whose resistance value changes depending on the ambient temperature in a constant magnetic field, a lead wire that applies a current to the magnetoresistive element and measures the output voltage, a coil that generates a magnetic field, and a coil that generates a magnetic field. 1. A friction degree measuring device for a magnetic head, characterized in that a thin film temperature sensor having a magnetic material guided to a resistive element, a substrate, and an insulating film is provided on the sliding end surface of the magnetic head.