JPH0618205A - Friction/abrasion evaluating unit - Google Patents

Abstract

PURPOSE:To obtain a friction/abrasion unit which can detect micro amount of friction/abrasion highly accurately under light load. CONSTITUTION:A sensor section 16 comprises a differential transformer 15 wherein a coil 13 is supported on a coil holder 17 and a core 14 is suspended from a load measuring section 18 mounted on the coil holder 17. The coil holder 17 can move up and down through a moving means 19 and a testing body 20 is set at the tip of the core 14. The coil holder 17 is moved up and down through the moving means 19 while measuring the load at the load measuring section 18 and a predetermined load is exerted on the specimen 11 placed on a sample stage 12 thus measuring friction/abrasion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction and wear evaluation apparatus for measuring the friction and wear of materials and coating films of members such as optical disks.

[0002]

2. Description of the Related Art Generally, recording media such as magneto-optical disks, CDs (compact disks), LDs (laser disks), and CD-ROMs (Read Only Memories).
y), CD-RAM (Random Access M)
2. Description of the Related Art A friction / wear evaluation device is used to measure the friction / wear of a protective coating film of a disk such as an memory (e.g., an electromagnetic disk) or an MD (magnetic disk) or the material of the coating film or the member itself of the disk. This type of evaluation device generally includes a mechanism that generates a force (load) for pressing two samples, a drive system that applies rotation or sliding between the samples, and a pressing system. It is mainly composed of a measurement system that separates and measures the force and the frictional resistance force. As the load generating mechanism, there are known a weight direct load type, a spring load type, a system in which a spring load is combined with a boom, a hydraulic type, a system using a bellows type air cylinder, a system using magnetic force, and the like. Further, the operation principle of the measurement system, that is, the sensor system is shown in FIG.
The principle as shown in is known.

FIG. 6 (A) shows a spring balance system in which a frictional force is applied to a sample mounted on a frame 3 balanced by a spring 1 and a spring 2, and the rotational force of the sample is centered by this frictional force. The attached pen 4 and rotary drum 5 can be directly captured. FIG. 6B shows a weight lever balance system, in which the pressing force and the frictional force by the weights W1, W2, W3 are balanced at the weight positions, and the scales of the weights W1, W3 at that time are read. .
FIG. 6 (C) shows a torque arm load cell system in which the load cell 7 is rotated by the arm 6 that tries to rotate by friction torque.
Press to measure the force at this time. FIG. 6 (D) shows a bending cell system, and FIG. 6 (E) shows a bending torque cell system, in which the frictional force by the bending load cell 9 attached to the torque measuring shaft 8 is measured as the torque most recently.

By the way, in the measurement of the frictional force, the pressing force and the frictional force act in a state orthogonal to each other, so that it is required to have an excellent ability to separate the two forces, and moreover, the measurement pressure is generated by the substance. It is required to have a small inertial mass and a high response frequency without disturbing the force. Therefore, generally, the methods shown in FIGS. 6D and 6E are mainly used as the pressing load measurement and the friction and wear sensor, and the load cell is used.

[0005]

However, in the above-mentioned conventional method, not only the load cannot be accurately applied to the sample, but also the friction wear due to the low load cannot be measured due to its mechanism. was there. Further, since the load cell is used for the measurement, a minute change amount of frictional wear cannot be detected, so that there is a problem that the degree of frictional wear cannot be accurately detected.

Further, due to the mechanism, not only the sliding friction of an arbitrary gap cannot be measured, but also the sliding friction and the gap friction cannot be measured by one device, and the device itself is large and expensive. there were. The present invention has been made in view of the above problems and was devised in order to effectively solve the problems. An object of the present invention is to use a differential transformer in a sensor section to reduce a small amount of friction at a low load. An object of the present invention is to provide a frictional wear evaluation device capable of detecting wear with high accuracy.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a sample table on which a subject is placed and is movable in a horizontal plane, a coil and a movable core. A sensor unit formed of a differential transformer, a coil holder for holding the coil of the sensor unit, a load measuring unit provided on the coil holder for supporting the core of the sensor unit in a suspendable manner, The evaluation device is configured by a moving unit that allows the coil holder to move toward the sample stage, and a sample provided on the core and in contact with the sample.

[0008]

Since the present invention is configured as described above, it is possible to apply a desired load to the object placed on the sample table by the core containing the sample while measuring the load by the load measuring unit. You can Then, the frictional wear of the subject becomes a displacement of the core of the differential transformer that constitutes the sensor unit, and is output based on the principle of the differential transformer. Therefore,
It becomes possible to accurately detect a minute amount of frictional wear with a low load.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the friction and wear evaluation apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a sectional view showing a main part of a friction and wear evaluation apparatus according to the present invention, and FIG. 2 is a partially cutaway view showing the entire friction and wear evaluation apparatus according to the present invention.
FIG. 3 is a schematic circuit diagram of the apparatus shown in FIG. 2, and FIG. 4 is an operation explanatory view showing the operation of the evaluation apparatus of the present invention.

As shown in the figure, this friction and wear evaluation apparatus 10
Is a sample table as a sample table on which an object such as a magneto-optical disk having a protective coating film formed thereon, for example, the disk 11 is placed and can be moved in a horizontal plane, for example, in the X and Y directions and rotationally. 12, a sensor unit 16 including a coil 13 and a differential transformer 15 having a movable core 14, a coil holding cylinder 17 as a coil holder for holding the coil 13, and a coil holding cylinder 17 A load measuring unit 18 that supports the core 14 so that it can be suspended, a micrometer 19 that serves as a moving unit that allows the coil holding cylinder 17 to move toward the sample table 12, and the core 14 are provided. It is mainly configured by the spherical specimen 20 that contacts the disk 11.

Specifically, the sample table 12 is formed in a disk shape like the disk 11, and the central portion of the lower surface thereof is connected to the rotary shaft of a rotary motor 21 for rotating the sample table 12. There is. This rotary motor 21
Is installed on a moving mechanism that is a combination of an X-direction moving table 23 that moves on the X-direction moving rail 22 and a Y-direction moving table 25 that moves on the Y-direction moving rail 24. Is capable of moving in X and Y directions and rotating.

The micrometer 19 is attached to a support base 26, and its expansion / contraction shaft 27 is provided penetrating downward. The micrometer 19 is provided with a scale 28 for adjusting the amount of movement of the telescopic shaft 27 with high precision. At the tip of the expandable shaft 27,
The upper end of the tubular support tube 32, which is open at the bottom, has the screw 2
It is firmly attached and fixed by 9 or the like. An electromagnetic coil 31 having a fixed core 30 formed along the circumferential direction is provided at the lower end of the support cylinder 32. In the hollow portion of the support cylinder 32, a coil holding cylinder 17 formed in a cylindrical shape having a smaller inner diameter than the inner diameter is inserted in a loosely fitted state, and is movable in the vertical direction. An engaging portion 33 protruding outward in the radial direction is formed on the peripheral portion of the ceiling portion of the coil holding cylinder 17, and the engaging portion 33 is formed.
By engaging with the stepped portion 34 formed above the electromagnetic coil 31, the coil holding cylinder 17 is prevented from falling off. A magnetic body, for example, an iron plate 35 is provided on the outer surface of the coil holding cylinder facing the electromagnetic coil 31, and the coil holding cylinder 17 is moved to the current position by energizing the electromagnetic coil 31 as needed. It is configured to be fixed to the support cylinder 32 side. The iron plate 35 is necessary especially when the material of the coil holding cylinder 17 is not a magnetic material in order to fix and open the coil holding cylinder 17 by magnetic force as described above. Therefore, the material of the coil holding cylinder 17 is made of a magnetic material. In the case of, it may not be provided.

On the other hand, a hollow cylindrical core 14 made of a magnetic material is provided in the vicinity of the distal end opening of the hollow portion of the coil holding cylinder 17.
Is hung from the load measuring unit 18 by a lead wire 36 made of Tyranno fiber or the like having a small elongation.
The length of the lead wire 36 is set so that the lower end portion of 4 protrudes downward from the lower end opening of the coil holding cylinder 17 by a slight amount. At the lower end of the coil holding cylinder 17 that surrounds the core 14, there is provided a coil 13 whose winding direction is reversed in the middle so as to form a differential transformer along the circumferential direction. , A differential transformer 15 is configured. Therefore, a slight mechanical movement or displacement of the core 14 in the vertical direction is converted into an electric signal and accurately detected as an output fluctuation of the differential transformer 15.

At the lower end of the core 14, a spherically shaped specimen 2 for measuring frictional wear during point contact is used.
0 projects slightly downward and is completely fixed,
It is adapted to come into contact with the disk 11 during measurement. A weight 37 is provided in the hollow core 14 for obtaining a predetermined pressing force against the disc during measurement. The weight of the weight 37 can be set to any value as needed. As the specimen 20, various specimens made of various materials such as plastic and stainless are prepared, and the specimen 20 including the core 14 can be changed according to the material of the specimen. Further, the load measuring unit 18 has a measuring table 39 having a support arm 38 penetrating the ceiling portion of the coil holding cylinder 17 in a loosely fitted state, and between the measuring table 39 and the ceiling portion, A load gauge, for example, a strain gauge 40 is provided, and this measuring stand 39
It is configured so that the weight of the load applied to can be accurately measured.

The schematic circuit configuration of such a device is as shown in FIG. 3, and the outputs of the coils 13 of the differential transformer 15 wound in mutually opposite directions are output via an amplifier 41, for example, a microcomputer or the like. Is connected to the control unit 42. A ROM 43 storing a program for operating the apparatus and a RAM 44 storing necessary data are connected to the control unit 42, and an output of the strain gauge 40 is also connected. Further, the control unit 42 includes a rotary motor 21 for moving the sample table 12 and an X motor.
A driver 45 that drives a motor (not shown) that moves the Y-direction moving tables 23 and 25 is connected to output a drive signal. In the illustrated example, only the driver 45 of the rotary motor 21 is shown.
Further, a recording unit 46 for recording the measurement result is connected to the control unit 42, and a display unit 47 showing the value of the strain gauge 40 is connected. Although not shown, a drive system for turning on / off the electromagnetic coil 31 is also connected to the control unit 42.

Next, the operation of this embodiment configured as described above will be described with reference to FIG. First, FIG.
As shown in (A), by energizing the electromagnetic coil 31, the support cylinder 32 and the coil holding cylinder 17 inserted in this hollow portion are provided.
Are mutually fixed by an electromagnetic force, and by moving the micrometer 19 in this state, the support cylinder 32 and the coil holding cylinder 17 fixed to this are lifted upward so that the lower end of the core 14 is also floated above the disk 11. , The total load at this time is measured by the strain gauge 40, and this value is R
It is stored in AM44. The load at this time is measured by the measuring table 39,
It becomes the total load of the specimen 20, the core 14, and the weight 37.

Next, as shown in FIG. 4 (B), the electromagnetic coil 31 is turned off to turn the support cylinder 32 and the coil holding cylinder 1 into contact with each other.
When the micrometer 19 is manually moved by disconnecting the connection with the probe 7, the specimen 20 at the lower end of the coil holding cylinder 17 and the lower portion of the core 14 comes into contact with the disk 11 and the lead wire 36 sags, so that the sample is free. The support cylinder 32 is lowered until the state becomes, and in this state, the load is measured by the strain gauge 40 and stored in the RAM 44. This measured value becomes the self-weight of the measuring table 39, and the self-weight of the measuring table 39 is subtracted from the total load previously measured to obtain the load applied to the disk 11 as the object in the subsequent process, that is, the core 1.
4, the total load of the specimen 20 and the weight 37 is calculated. still,
This calculation is performed by the control unit 42.

Next, as shown in FIG. 4 (C), the gap friction wear measurement is performed. That is, by energizing the electromagnetic coil 31, the support cylinder 32 and the coil holding cylinder 17 are coupled, and by manually operating the micrometer 19, the coil holding cylinder 17 is gradually raised and the value of the display unit 47 is watched. At the same time, the coil holding cylinder 17 and the core 14 are pulled up until the lead wire 36 is stretched so that this value becomes the sum of the load applied to the subject obtained by the operation shown in FIG. 4B and the own weight of the measuring table 39. . At this time, the load applied to the disk 11 is very close to zero, and the spherical specimen 20 is in a point contact state,
There is a very small gap with the disk 11. At this time, the lower end of the coil holding cylinder 17 is completely separated from the disc 11.

In this state, the drive of each table is driven to move the disk 11 in the X and Y directions or in the rotational direction, so that the surface of the disk 11 is preliminarily coated with a lubricant or the like, which is a gap friction wear, that is, a boundary lubrication. Boundary friction due to and fluid friction due to fluid lubrication are measured. Disk 1
When one surface is impregnated with a lubricant, its lubricity and the like are measured. In this measurement, the frictional wear value and this displacement are mechanical displacements of the core 14 in the vertical direction via the specimen 20, and as a result, the voltage or phase of the coil 13 of the differential transformer 15 constituting the sensor unit 16 is changed. It appears as a change and is converted into a change in the electric signal. This signal is input to the control unit 42 via the amplifier 41, where after the predetermined arithmetic processing is performed, the result is recorded in the recording unit 46 or the like.

Further, during the measurement, the movement of the specimen 20 and the core 14 in the horizontal direction is restricted by the magnetic force of the differential transformer structure, so that the specimen 20 or the like may shake laterally even if the specimen table 12 moves. Absent. Further, by finely adjusting the micrometer 19 while gazing at the strain gauge 40, it becomes possible to accurately detect a minute amount of frictional wear with a low load. Next, a sliding friction wear measurement is performed. That is, from the state of the above-described measurement of the gap friction and wear, FIG.
By operating the micrometer 19 as shown in, the coil holding cylinder 17 is gradually moved downward and lowered until the value of the strain gauge 40 becomes the weight of the measuring table 39, so that the specimen 20 is completely placed on the surface of the disk 11. They are brought into contact with each other and the lead wire 36 is flexed to be in a free state. At this time, the lower end of the coil holding cylinder 17 is set apart from the disk surface so as not to come into contact with it. In this case, the total weight of the core 14, the sample 20, and the weight 37 is applied to the disk surface.

In such a state, by moving the disk 11 in the X and Y directions and the rotation direction in the same manner as described above, the mechanical displacement in the vertical direction of the core 14 is converted into the displacement of the electric signal, that is, the differential signal. An electrical signal is taken out by the principle of a transformer to measure sliding friction wear, for example, dry friction. When measuring the frictional wear, it is preferable to move the disk 11 as the subject a plurality of times and average the displacements and displacements of the outputs of the respective differential transformers to obtain the measured values.

By changing the weight of the weight 37 in the core 14, the friction load to be measured can be set arbitrarily. Further, by preparing a plurality of cores of different materials for the specimen 20 and replacing them, it is possible to measure the friction and wear of the specimens of different materials, without being restricted by the material of the specimen. Further, if a temperature sensor is incorporated in the sample 20, the sample 20 can be measured when friction and wear are measured.
The frictional heat generated between the object and the subject can also be measured. Furthermore, it becomes possible to perform the gap friction wear measurement and the sliding friction wear measurement with one device.

In the above embodiment, the spherical specimen 20 is used to perform the point contact, but the present invention is not limited to this, and the bottom is flat as shown in FIG. 5, for example. A conical specimen 48 may be used, and a weight 49 may be provided on the upper portion thereof. According to this, it becomes possible to measure frictional wear at the time of surface contact. Further, in the above-mentioned embodiment, the case of performing the frictional wear measurement of the protective coating film of the magneto-optical disk has been described, but the present invention is not limited to this, the measurement of the lubricant of the magnetic disk, the lubricating coating film, the coating film, etc. Can also be used to measure frictional wear of any material or member.

[0024]

As described above, according to the friction / wear evaluation apparatus of the present invention, the following excellent operational effects can be exhibited. Since the load can be accurately measured by the load measuring unit, not only the load can be accurately applied to the subject, but also friction and wear under a low load can be measured. Further, since the height can be adjusted with high accuracy by the moving means, it is possible to measure the sliding friction wear of an arbitrary gap. Further, since the differential transformer is used for the sensor unit, not only the friction and wear can be accurately measured but also this minute change amount can be detected. Also,
The size can be reduced as compared with the conventional device, and the device can be provided at a relatively low cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a friction and wear evaluation apparatus according to the present invention.

FIG. 2 is a partial cross-sectional view showing the entire frictional wear evaluation apparatus according to the present invention.

FIG. 3 is a schematic circuit diagram of the device shown in FIG.

FIG. 4 is an operation explanatory view showing the operation of the evaluation device of the present invention.

FIG. 5 is a diagram showing a modified example of the sample used in the evaluation apparatus of the present invention.

FIG. 6 is a principle diagram showing a measurement principle of a conventional friction and wear evaluation device.

[Explanation of symbols]

10 ... Friction and wear evaluation device, 11 ... Disk (subject),
12 ... Sample table (sample table), 13 ... Coil, 14 ...
Core, 15 ... Differential transformer, 16 ... Sensor part, 17 ... Coil holding cylinder (coil holding body), 18 ... Load measuring part, 19
... Micrometer (moving means), 20 ... Sample, 32 ... Support tube, 36 ... Lead wire, 37 ... Weight, 39 ... Measuring stand,
40 ... Strain gauge.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // G01N 19/02 Z 2107-2J

Claims (1)

[Claims] 1. A sample stage on which a subject is placed and is movable in a horizontal plane, a sensor section including a differential transformer having a coil and a movable core, and the coil of the sensor section. A coil holder for holding, a load measuring part provided on the coil holder for supporting the core of the sensor part in a suspendable manner, and a moving means for moving the coil holder toward the sample stage. A friction / wear evaluation apparatus comprising: a sample provided on the core and in contact with the subject.