SU1357789A1 - Arrangement for friction test of materials - Google Patents

Abstract

The invention relates to the testing of materials by friction for certain tribomechanical properties, namely the wear resistance depending on the distribution of heat flux generated by friction. The aim of the invention is to improve the accuracy in estimating the coefficient of distribution of heat fluxes. Sample holders 9 (L oo el oo

Description

and 10 is made of heat-conducting material, for example copper, and heat insulation rosans from spindles 4 and 5 with the help of sleeves 13 and 14 of heat-insulating material. All heat generated on the friction surfaces is transferred to heat exchangers 25 and 26 ,. installed at the free ends of the sample holder holders 9 and 10 opposite to the installation site of samples 11 and 12, heat is transferred through the cheeks to the sample holder

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The invention relates to the testing of materials by friction to determine their tribomechanical properties.

The purpose of the invention is to improve the accuracy in estimating the coefficient of distribution of heat fluxes during friction due to the concentration of heat fluxes at their measurement points in the gap between the end face and the heat exchanger, increasing the heat flux gradient at measurement points and thereby eliminating errors associated with heat dissipation the gap between the sample and the heat exchanger and the uniform heating of the heat transfer element.

The drawing shows a diagram of the device.

The device includes a housing 1 in which heads 2 and 3 are movable and fixed, respectively, two spindles 4 and 5 are coaxially mounted to each of heads 2 and 3, spindles 4 and 5 are installed in heads 2 and 3 by means of radial thrust bearings 6, which makes it possible for them to rotate. In each spindle 4 and 5 eccentrically mounted with eccentricity e relative to their axes two fingers 7 and 8 in which specimen holders facing one another are mounted, shaped as mandrels 9 and 10 intended for installation and samples 11 and 12 and heat extraction from them Between mandrels 9 and 10 and fingers 7 and 8 are installed sleeves 13 and 14, preventing heat transfer from mandrels 9 and 10 to fingers 7 and 8,

57789

zhatel x 9 and 10 ,. acting as thermal reference resistances connected in series to the heat transfer circuit of the friction zone to heat exchangers 25 and 26. Measuring the temperature difference on the neck of the cell from sample holders 9 and 10 using temperature sensors Ti and Tz allows one to calculate the heat fluxes coming from each sample 11 and 12, with a high degree of accuracy, 1 Il.

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a part of each of the mandrels 9 and 10 is made in the form of a neck with a length of I of a constant cross section and forms a closed annular cavity with the inner surface of heat insulating and concentrating passing heat flow bushings 13 and 14,

At the boundaries of the necks in each mandrel 9 and 10, two temperature sensors T and Tj are fixed by one-piece connection, which are means of measuring the heat flux. The fingers 7 and 8 are installed in the spindle x 4 and 5 by means of angular contact bearings 15, providing the ability to rotate the fingers. At the ends of the fingers 7 and 8, two rocking chairs 16 and 17 are fastened, the ends of which are connected to the clearance and the heads 2 and 3 by means of bearings 18 and made in the heads 2 and 3 of the slots 19, the device contains a rotational drive (not shown), from which movement is transmitted to pulleys 20 and 21 fixed to spindles x 4 and 5, allowing them to rotate in opposite directions. The loading mechanism interacts with the spindle 4 and is a bracket 22 resting against the spring 23. With an adjusting screw 24, the temperature gradient in each mandrel 9 and 10 is measured by temperature sensors T, and T (for heat flow from sample 11) The temperature sensors T and T are installed at the boundaries of the necks and fixed permanently at a distance of 1 less than the heat insulating sleeves 13 and 14. To regulate the distribution of heat flow, the device has heat exchangers 25 and 26, made for example in the form of refrigerators firs.

The device works as follows.

Through the loading mechanism, specimens 11 and 12 are loaded with the required axial force. Spindle m 4 and 5 is transmitted from the drive. Due to the eccentric arrangement in the spindle x 4 and 5 fingers 7 and 8 and the connection of the latter with heads 2 and 3, samples 11 and 12 make a relative alternating movement. Due to this kinematics, the signal from the sensors T and Tj can be transmitted to the recording devices directly without current collection. Separating heat from samples 11 and 12 is transferred to mandrels 9 and 10, respectively, and then through the neck, which is thermal resistance in the path of heat transfer from the sample to the environment. Since the sample holder and the cheek are thermally insulated with a sleeve and a radial gap, all the heat from samples 11 and 12 passes through the corresponding neck. Measuring T and T on each neck with the help of temperature sensors allows to calculate heat fluxes coming from each sample 11 and 12 into the environment using the formula q K, (T, - T) with the thermal resistance of the neck at a length of 1 ,, by calibration or by formula

B

 , 2, where AE thermal conductivity of the material,

 neck section. Since the sample holder does not understand when changing the samples, we can assume the value of K to be a constant value. Thermocouples are fixed in the necks constantly, therefore errors in the measurement of T (and T are also constant and minimal. Thinning of the cross section in the neckKey

Editor V.Danko

5989/41

Circulation 776 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

kah concentrates heat flow, increasing dT. These factors make it possible to increase the accuracy of determining the magnitude of the heat flux coming from the friction zone towards the corresponding sample.

Claims (1)

Invention Formula A device for testing friction materials, comprising a body, a movable and a fixed headstock mounted on it, each spindle being coaxially aligned with each other, two spindles, a rotational drive, kinematically connected, with spindles, each being eccentrically arranged in each; the spindle has two sample holders, each of which is made in the form of a mandrel with a nest for the sample at one end installed rotatably about its axis, two rockers, each of which is fixed at one end to the corresponding sample holder, and the other with a gap headstock, loading mechanism, heat exchangers connected with sample holders and measuring means in the form of at least two temperature sensors, characterized in that, in order to improve accuracy 5 when estimating the coefficient of heat flow distribution during friction, it is equipped with two heat insulating sleeves installed each coaxially on a corresponding mandrel, in the middle of each mandrel the neck is fixed This section, forming a closed annular cavity together with the inner surface of the corresponding insulating sleeve, temperature sensors are rigidly fixed on the corresponding necks , and the heat exchangers are installed at the free ends of the mandrels. five Compiled by V. Spinev Tehred L. Serdyukova Proofreader M. Maksimishinets