RU2461811C1 - Device to define friction factor of materials - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: device fitted on drive shaft comprises two opposed blocks with riders interacting with disc and loaded via system of levers that makes closed driving loop interacting with measuring device. Said system comprises top and bottom levers coupled, on one side, by lever articulated to said bottom lever and furnished with elastic loading element. On opposite side, said lever is articulated with top level and provided with device to control mutual arrangement of said levers. Bottom block with rider is dipped into oil bath and locked by ball at bottom lever while top block with rider is connected with temperature control thermocouple and locked at system top lever by ball. Moment of friction is measured without cutting out of drive and interrupting test process in interaction between loading levers and measuring device. Transfer to the measuring position is carried out by switch mechanism.

EFFECT: higher validity, reduced production and operation costs.

3 cl, 2 dwg

Description

The invention relates to mechanical engineering, and in particular to methods for studying the coefficients of friction of materials.

Known friction machines: machines for testing materials for friction types 2168 UMT and MGUT-01.

The universal machine for testing materials for friction 2168 UMT is designed for testing friction, antifriction and lubricants for friction and wear (see the website http://www.tochpribor-nw.ru/production/friction-testing). Testing schemes: a disk finger, a disk block, a core finger. The drive of the machine is electromechanical with smooth speed control. The pressure of the samples is pneumatic (from the mains or from the cylinder), the measurement of the pressure is manometric. Cooling - water (from the water supply). Programming test modes is possible. In the process of testing, the moment of friction, the pressure force, temperature, speed, friction path are measured.

The disadvantages of the machine 2168 UMT include high energy consumption, high metal consumption and large overall dimensions.

The MTUG-01 friction machine is designed to carry out friction and wear tests of metal and nonmetallic materials under various lubricants (see the website http://www.nanotech.ru/pages/about/mtu-1.htm).

The test method is based on the mutual movement of the test pieces pressed against each other with a given force in or without lubricant. During the test, the moment of friction is recorded with a graphic display of its change, as well as the temperature of the test samples. Contact scheme: end face of a rotating roller and fixed disk. The moment of friction is recorded by a strain gauge, the temperature by a thermocouple.

The disadvantages of the MTUG-01 machine include design complexity and high cost.

The closest in technical essence, taken as a prototype, is the SMC-2 universal friction machine (see the website http://www.gubkin.ru/faculty/mechanical_engineering/chairs_and_departments/Uc hebn_nauch_proizv_centr_po_remontu / experiment / experimentl.php). SMC-2 friction machine is designed for testing materials for friction and wear during rolling, rolling with slipping and sliding according to the “disk-block” scheme. The disk (cylindrical sample) is mounted on the drive shaft of the machine, the rotation of which is carried out by an electric motor through a belt drive. The loading of the samples is carried out through the counterbody installed in the block and interacting with the disk, and the movement carriage is balanced by the counterweight, which allows testing at low loads on the friction pair.

The disadvantages of the SMC-2 friction machine include measurement errors caused by the massive loading mechanism and runout of the friction surface, friction in the bearings, as well as the complexity of the design.

The objective of the invention is to develop the design of the device in order to obtain more reliable test results, reduce installation costs, as well as reduce material consumption.

The solution to this problem is achieved by the fact that the device for determining the coefficient of friction of materials according to the "disk-block" scheme, containing a block with a counterbody interacting with a disk (cylindrical specimen) mounted on the drive shaft, in contrast to the prototype includes two diametrically located blocks with counter bodies interacting with the disk, the loading of which is carried out through a system of levers forming a closed power movable circuit and interacting with the measuring device. The system comprises upper and lower levers connected on one side by a lever pivotally attached to the lower lever and provided with an elastic loading element, and on the other hand by a lever pivotally attached to the upper lever and provided with a device for adjusting the relative position of the levers between each other; the lower block with the counterbody is immersed in the oil located in the bath mounted on the lower lever and fixed through the ball body on the lever, and the upper block with the counterbody connected to the temperature control thermocouple is fixed on the upper lever of the system through the ball body.

The device further comprises a cam mechanism for switching the lever system from the operating position to the position of measuring the friction moment during the test without disconnecting the drive and interrupting the test process.

The use of this device for determining the coefficient of friction allows to obtain more reliable test results by reducing the dynamic component of the load of the friction pair, which is caused by practical beating of the cylindrical surface of the disk, which (the dynamic component) is proportional not only to the amount of runout, but also to the mass and rigidity of the loading system ; the loading force of the friction pair due to the developed design of the device with two counterbodies has a slight effect on the bearings of the drive shaft.

The absence of a radial load of the bearings of the drive of the friction discs allows the use of any adjustable drive that provides a given speed, which significantly reduces the cost of the design and reduces the cost of manufacturing and operating the installation.

As a result of the patent search, no technical solutions were identified that are identical to the claimed one, which meets the criterion of "novelty."

The proposed device can be used in mechanical engineering to determine the coefficient of friction, which meets the criterion of "industrial applicability".

A new set of features, namely: the presence of a system of levers with an elastic loading element, forming a closed power movable circuit for loading friction pairs and interacting with a measuring device, upper and lower diametrically located counterbodies fixed in blocks and interacting with the disk, allows you to unload the bearings of the drive shaft and get a new economic effect: reduce the cost of the device and increase the accuracy of measurement, which confirms the causal relationship of the new aggregate prize and the results achieved, which were not known from the prior art before the creation of this technical solution, which allows us to conclude that the technical solution meets the criterion of "inventive step".

The invention is illustrated in the drawing, in which Fig. 1 shows a schematic diagram of a device for determining the coefficient of friction, Fig. 2 is a view A of Fig. 1. The proposed device consists of a drive 8, on the output shaft of which is attached a disk 14 (cylindrical sample) for testing (Figure 2); the upper 12 and lower 16 counter bodies located diametrically to each other, mounted in blocks 10 and 17, respectively, with the lower counter body 16 immersed in oil located in the bath 15 mounted on the lever 7 (Figure 1). The thermocouple 13 is attached to the block 10. The counterbody 12 and 16 are pressed with a certain force to the disk 14 using an elastic element in the form of a spring 4 located on the lever 6 passing through the hole in the lever 2, corresponding to the diameter of the lever 6. The elastic element on the lever 6 is fixed nut 5. The system formed by levers 2, 6, 7 and lever 9, equipped with a device for regulating the relative position of the upper 2 and lower 7 levers together, forms a closed power circuit for loading friction pairs and is supported at one end by a measuring device 1 (weighing device). The device for adjusting the relative position of the levers 2 and 7 is a lever 9 with a threaded control connection along the length of the lever. The lever system is switched from the operating position to the measurement position by means of a cam mechanism 3 located on the frame of the measuring device and in contact with the upper lever 2, which is two racks mounted on the frame of the measuring device with a cam installed between them on the axis, changing depending from the position of the work or measurement, its position in relation to the lever 2.

The device operates as follows: the disk (sample) is mounted on the output shaft of the drive 8. In operating mode, the lever 2 is in a horizontal position, this is done manually using the mechanism 3 switching between positions, while the lever system is in a loaded state. When the mechanism 3 is switched to the measuring position, the frictional moment arising during the rotation of the disk is transmitted by means of the lever 2 to the measuring device 1, according to the readings of which the friction coefficient is determined. The temperature in the contact zone is recorded by thermocouple 13. Two such devices can be mounted on the drive shaft and simultaneously determine the friction coefficients of two different samples, or carry out comparative tests for different materials.

The use of this device to determine the coefficient of friction allows you to get more reliable test results, reduce installation costs.

Claims (3)

1. A device for determining the coefficient of friction of materials according to the "disk-block" scheme, containing a block with a counterbody and a disk mounted on the drive shaft, characterized in that it includes two diametrically located blocks with counterbody interacting with the disk, the loading of which is through a system of levers forming a closed power movable circuit and interacting with a measuring device; the system comprises upper and lower levers, interconnected on one side by a lever pivotally attached to the lower lever and provided with an elastic loading element, and on the other hand, by a lever pivotally attached to the upper lever and provided with a device for adjusting the relative positions of the levers together; the lower block with the counterbody is immersed in the oil in the bath and fixed through the ball body on the lower lever, and the upper block with the counterbody connected to the temperature control thermocouple is fixed on the upper lever of the system through the ball body. 2. The device according to claim 1, characterized in that the measuring device uses a weight device. 3. The device according to claim 1, characterized in that it further comprises a mechanism for switching the lever system from a fixed operating position to the position of measurement of the friction moment.

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