KR20000075336A - Friction tester for Rubber - Google Patents

Abstract

PURPOSE: A rubber friction testing machine is provided to simplify the structure and manipulation and obtain precise frictional characteristics since inertia due to relative motion of a test specimen and fixing elements of the test specimen does not act on a measuring result of a frictional force. CONSTITUTION: A rubber friction testing machine includes a measuring device(1) having a balancing arm(14) mounted a weight(13) at one side of a main arm(12) fixed on a base, a testing arm mounted at the other side, and a friction pin(15) connected to the testing arm perpendicularly to a rod cell(28), and a test specimen operating device(2) having a rotatably turn table to be fixed with a test specimen, wherein the friction pin is mounted with a strain gauge in the middle for measuring deformation ratio and inertia due to the motion of the test specimen is not included in the friction test data, thereby obtaining precise frictional characteristics data.

Description

Rubber friction tester {Friction tester for Rubber}

The present invention relates to an elastic material friction tester for testing the friction properties of elastic materials, in particular rubber.

Recently, as the performance of rubber materials has been variously improved, the use of rubber as an industrial material has been widely developed. Rubber has a small non-linear modulus of elasticity, a very high elongation to break, easy torsional deformation, electrical insulation and chemical resistance, and a sealing material to prevent infiltration of dust and water, and to prevent noise and vibration. In addition to being widely used as a dustproof material, it is widely used as a structural element or a power transmission material.

Since rubber has different friction and abrasion characteristics from metals, and the formulation of the rubber is different to suit the friction characteristics, it is very important to measure the friction characteristics. The wear and friction properties of rubber are tested by rubber material producers and users independently, and are tested for their purpose. However, international standards are not specified.

In order to measure the coefficient of friction related to the friction characteristics of rubber, the relative linear or rotational frictional motion appears between the specimen and the test arm that emits the signal so that the measured vertical and friction forces acting between the specimen and the test arm are measured. Calculate from Therefore, in order to measure accurate friction force, relative motion must be performed under stable vertical force between the test specimen and test arm, and in order for this relative motion to occur, the relative motion and state of motion are controlled and monitored and the result is measured. It should be reflected in friction. The measured data was calculated by the controller and showed the required coefficient of friction.

The conventional friction tester only measures the normal and frictional forces applied to the test arm when the specimen and the test arm make relative relative or circular motions on the contact surface and measure the coefficient of friction from this data. For example, in the helidon-type friction measuring device, the friction coefficient is calculated by measuring the vertical force and friction force applied to the test arm by allowing the specimen to move at a constant speed in contact with the test arm connected to the load cell by means of a balancer and a weight. In the friction tester, the specimen was fixed to the support plate connected to the load cell, and the weight was placed on the opposite side of the specimen to measure the normal force and move the specimen in contact with the fixed friction surface. The conventional friction tester includes the inertia force due to the movement of the specimen in the force to be measured, the friction force is different depending on the model used, it was difficult to obtain accurate data.

The present inventors have studied in order to solve the problems of the conventional rubber friction test described above, so that the relative motion of the specimen and the test arm is the rotational movement of the specimen, the vertical force is measured by the load cell, and the frictional force is measured by the equivalent force using bending deformation. As the frictional force is not included in the inertia force due to the relative movement of the specimen, it has been found that the above-mentioned problems are solved, thereby completing the present invention.

It is an object of the present invention to provide a friction measuring instrument capable of measuring an accurate coefficient of friction.

The object of the present invention described above is achieved by the friction tester of the present invention, which allows the specimen to be rotated by the turntable to allow rotational movement and frictional force is measured by the main arm and the balancing arm connected to the test arm contacting the specimen.

The present invention consists of a friction tester comprising a main arm fixed to a base, a balancing arm connected to one side of the main arm, a test arm connected to the other side of the main arm, and a friction friction pin having a strain gauge in the middle portion.

According to the present invention, the concentrated load due to the frictional force acts on the end of the friction pin, and thus the bending moment and the shear force appear on the pin. The bending moment and the shear force are measured by a strain gauge and used for calculating the friction force. In addition, since the friction pin is in contact with the specimen vertically above the specimen, the vertical force is transmitted vertically through the pin, so that both the friction force and the vertical force act on the pin, so that the friction force is applied in the vertical force state. When this additionally occurs, the strain and stresses measured by the strain gauges include both friction and normal forces. At this time, the error appearing when calculating the friction force using the strain gauge can be compensated to the negligible degree by the adjustment of the auto balancing, so only the friction force generated by the relative motion is detected as a signal.

1 is a partial cutaway front view of a friction tester according to the present invention;

2 is a partial cross-sectional view of the measuring device according to the present invention;

Explanation of symbols for main parts of the drawings

Measuring device ... 1 Specimen actuator ... 2 Main arm ... 12 Weight ... 13 Balancing arm ... 14

Friction Pins ... 15 Test Arms ... 16 Support Frames ... 20 Spindles ... 21 Turntables ... 22

Supports ... 26 Bolts ... 27 Load Cells ... 28 Motors ... 32 Belts ... 34 Supports ... 40

Rotating body ... 46 Locking pin ... 52 Cylindrical groove ... 58 Motor ... 64 Flexible joint ... 66

Thermostat ... 70

Hereinafter, the present invention is described in detail with reference to the drawings.

1 is a schematic diagram of a friction tester according to the present invention, wherein the friction tester has a main arm 12 fixed to a support frame 10, a balancing arm 14 having a weight 13 fixed to one side of the main arm, and A rotating shaft rotatably installed on the support frame 20 and the measuring device 1 having a test arm 16 connected to the main arm 12 in the form of a cantilever and having a friction pin 15 attached perpendicularly to the outer end thereof. And a specimen operating device 2 having a turntable 22 installed at 21 and a specimen mounting plate 23 fixed on the turntable.

According to FIG. 2, the main arm 12 of the measuring device 1 is formed of a rectangular tubular body and fixed with bolts 27 to a support 26 fixed to the base 24. The balancing arm 14 is slidably coupled to the main arm 12 to be fixed by bolts, and has a support section 13a in which the weight 13 is slidably coupled to the outer end thereof. The balancing arm 14 is slidably coupled to the main arm 12 to be fixed by bolts, and at its outer end, the friction pin 15 connected to the load cell 28 is rotatably installed. This friction pin 15 can be rotated by the motor 32 to the belt 34. The friction pin 15 is rotatably installed in the multi-stage cylindrical support 40 installed in the test arm 16, and the upper end of the friction pin 15 is attached to the load cell 28 installed on the upper surface of the test arm 16. Installed to connect. The friction pin 15 is formed in a circumferential shape and a spherical friction piece 15a is formed at the contact end of the lower end, and the upper end of the friction pin 15 is a bearing fixed to the bottom surface of the case 30 of the load cell 28. The rotating body 46 is rotatably supported by the bearings 45a and 45b provided on the inner circumferential surface of the 44 and the support 40, and is connected to the pulley 33 of the motor 32 by a belt 34 at the upper end thereof. ) Was fixed to install. The bearing pin 50 which supports the outer circumferential surface of the upper end of the support frame 40 is fixed inside the rotor 46 so that the friction pin 15 is driven by the rotational force of the motor 32 transmitted through the belt 34. This is to be rotated. The above-described support 40 and the friction pin 15 are formed with a hole into which the fixing pin 52 is inserted. When the friction pin 15 is to be rotated, the fixing pin 52 is pulled out and the friction pin 15 is removed. When not rotated, the pin 52 was inserted and fixed. In addition, a fixing key 54 may be installed at the end of the friction pin 15 so as to measure a frictional force on a cylindrical sample by installing a disc if necessary. The above-described friction pin 15 is provided with a strain gauge 56 in the middle portion. In order to minimize the error when measuring the friction force by the apparatus of the present invention, the circular groove 58 is formed so that the aforementioned strain gauge 56 is far from the friction end and the diameter of the gauge attachment portion is reduced. It is desirable to make the diameter of the end 60 in contact with the specimen smaller.

The specimen actuator 2 is fixed on the turntable 22 fixed to the rotating shaft 21 installed on the cylindrical frame 20 and on the temperature controller 36 and the temperature controller fixed to the upper surface of the turntable 22. Consisting of a specimen holding plate 23. According to FIG. 4, the support frame 20 of the test piece operating device 2 has a large diameter cylinder 62 and a small diameter cylinder 63 connected by bolts 61 and a flexible joint 66 to a motor 64 therein. Rotating shafts 21 connected to each other were installed. The rotary shaft 21 is rotatably supported by the bearings 68a and 68b. The turntable 22 is installed at the upper end thereof, and the temperature controller 36 is installed on the upper surface of the turntable. The specimen to be tested on the top was fixed. The above-described temperature controller 36 is formed in a closed box shape with an empty inside and has an injection hole (not shown) for injecting a temperature control medium therein.

In the above-described apparatus of the present invention, the friction pin 15 fixed to the upper surface of the temperature controller 36 is fixed with the fixing pin 52, the specimen is fixed to the specimen fixing plate 71, and then the turntable 22 is rotated or The turntable 22 is fixed, the fixing pin 52 is removed, and the friction pin 15 is rotated with the motor 32 to calculate the normal force measurement from the load cell 28 and the strain signal from the strain gauge 56. Send it to the device to measure the frictional force.

According to the present invention described above, since the structure is simple and easy to operate, when the friction force is measured, the inertia force due to the relative movement of the specimen and the specimen holding members does not affect the measurement result, thereby obtaining more accurate friction characteristics than the conventional friction tester. It has an effect.

Claims (7)

Friction connected vertically to the load cell 28 on the test arm by installing a balancing arm 14 having a weight 13 on one side of the main arm 12 fixed to the base and a test arm 16 on the other side. A friction force tester comprising a measuring device (2) comprising a measuring device (1) by installing a pin (15) and a rotatable turntable to secure the specimen. 2. Tester according to claim 1, characterized in that a strain gauge (56) is connected to the friction pin (15). 2. A tester according to claim 1, characterized in that the friction pin (15) has a minor diameter portion formed in the middle portion of the annular groove (58) and the strain gauge (56) is installed in the aforementioned annular groove (58). The friction pin (15) is rotatably supported on a support (40) fixed to the test arm (16), and a rotating body (46) is attached to the upper end of the friction pin (15). The whole is connected to the motor (32) installed in the test arm (16) by a belt (34). 2. The tester according to claim 1, wherein the friction pin (15) is fixed to the support (40) by a fixing pin (52). 2. A tester according to claim 1, characterized in that the turntable (22) is made rotatable by a motor (64) installed in the frame (36). 2. A tester according to claim 1, characterized in that the specimen actuator (2) has a temperature controller (36) on top of the turntable (22).