RU208869U1 - Device for determining the coefficient of friction of lubricants - Google Patents

Abstract

The utility model relates to the field of mechanical engineering, namely to methods for studying the coefficient of friction of lubricants of various compositions. The device for determining the coefficient of friction of lubricants contains a movable shaft, on which there is a thrust nut, a conical guide sleeve, guide studs, a counterbody in the form of a conical sleeve, an indenter, a guide sleeve, while an indenter is installed in the hole of the movable shaft with the ability to contact with the counterbody at one end in the form of a conical sleeve, and the other - with a load spring, which serves to create the necessary load of contact metal pairs by selecting springs of different stiffness. A nozzle is installed on the movable shaft with the possibility of supplying a lubricating process medium (STS) in a sprayed state directly into the contact zone of metal pairs. To register the torque, an M30-3-6k electronic three-component dynamometer connected to a PC was used, which makes it possible to improve the accuracy of measuring the friction coefficient of lubricants. In order to create the required temperature of the friction zone, the device is equipped with an induction furnace located on a conical guide sleeve and isolated from the external environment by a conical insulating sleeve. The heating temperature of the contact zone is controlled by a thermocouple formed by chromel-kopel electric wires, the junction of which is located in the indenter hole, in turn, the registration of thermoEMF values is carried out using a millivoltmeter. The technical result of the utility model is the need to expand the arsenal of technical means to improve the accuracy of determining the coefficient of friction of lubricants by changing the temperature of the friction zone in a wide range. 1 ill.

Description

The utility model relates to the field of mechanical engineering, namely to methods for studying the coefficient of friction of lubricants of various compositions.

A device for testing rubbing materials and oils (A.S. USSR No. 983522, IPC G01N 19/02. A device for testing rubbing materials and oils. Bull. No. 47, 1982 Analogue) containing a frame, sample holders installed on it and a counter-sample, nodes for measuring the moment of friction and loading of the samples and a drive for rotating the samples, a plate installed perpendicular to the frame with the possibility of moving along it, three platforms, of which the middle one is hinged on the plate, and the other two are installed at an angle of 45 ° to the middle one, which located on the platforms and interacting with countersamples holders, guide and clamping rollers mounted on the plate with the possibility of rotation in the plane of the holders, transmission links interacting through rolling bearings, respectively, with countersamples holders and loading units, and the latter are equipped with rods having two degrees of freedom (mechanisms to transfer the load to the countersamples).

The main disadvantage of the known device lies in the complex and precise installation of the transmission links at right angles to the guides, which leads to large errors in the results obtained during testing.

A device is known for testing materials for friction and wear in space, containing a friction unit "disk-indenter", which is a disk with two friction surfaces and on which two hemispherical indenters slide (see Journal "Friction and Wear", vol. 24 , No. 6, 2003, pp. 626-635. Analogue). In this case, the disk is rigidly fixed on the drive shaft, and the indenters are on special levers. The load on the indenters is carried out using a calibrated spring.

All friction units are driven by the drive output shaft through gears. The moment of friction in the "disk-indenter" pair is measured by an elastic tensometric beam. Electrical signals are fed to two strain gauge transducers, from which they are transmitted to the recording device.

The disadvantages of the known device are the complexity of the design due to the use of a large number of elements, the complexity of its use due to the constant calibration of the loading springs, affecting the measurement error, as well as low sliding speeds and specific pressures in the contact of the indenter and disk.

A device for determining the coefficient of friction of lubricants is known (patent for a utility model of the Russian Federation No. 192398 MPK G01N 19/02, publ. bore (counterbody), fluoroplastic bushing, loading (locking) screws, thrust ring, thrust bearing, and bushings for torque transmission.

The principle of operation of the device is as follows: the indenter is fixed in the hole of the fixed shaft of the device and a sleeve with a conical hole is installed. With the help of loading (fixing) screws, pressure is created on the contact pair and controlled by a torque wrench, then the lever is installed on the sleeve, the engagement of which is carried out using holes located on the outer part, while a drive cable with a dynamometer is fixed on the opposite side of the lever. Changing the position of the angle of the lever is carried out using a pulley and a handle, while the system is in a loaded state. When the device is rotated to the measurement position, the friction moment that occurs during the rotation of the indenter is transmitted by means of a lever to the measuring device, according to the readings of which the friction coefficient is determined.

The disadvantages of the known device are the low versatility of replacing a worn conical bushing (counterbody) with a new one, associated with the complexity of its manufacture, as well as obtaining holes for fixing and holes for guide pins, leading to additional material costs and manufacturing time.

The closest in technical essence is a device for determining the friction coefficient of lubricants (utility model patent of the Russian Federation No. 200035 MPK G01N 19/02, publ. 01.10.2020. Bull. No. 28. Prototype), containing a movable shaft on which a thrust nut is located , a conical guide bushing, guide pins, a counterbody in the form of a conical bushing, an indenter, a guide bushing, where a half indenter is installed in the hole of the movable shaft, with the ability to contact with the counterbody in the form of a conical bushing at one end, and with a load spring at the other, which serves to create the necessary loads of contact metal pairs by selecting springs of different stiffness. A nozzle is installed on the movable shaft with the possibility of supplying a lubricating process medium (STS) in a sprayed state directly into the contact zone of metal pairs. To register the torque, an M30-3-6k electric three-component dynamometer connected to a PC was used, which makes it possible to improve the accuracy of measuring the friction coefficient of lubricants. To reduce the friction that occurs when the tapered guide bush and guide bush come into contact with the movable shaft, linear bearings are located in the bores of the tapered guide bush and guide bush, which are fixed with circlips. The technical result of the utility model is to increase the accuracy of determining the coefficient of friction of lubricants and the versatility of replacing the tested samples.

The disadvantages of the known device is the inability to study the coefficient of friction of lubricants at high temperatures of the contact zone of metal pairs.

The technical result of the utility model is the need to expand the arsenal of technical means to improve the accuracy of determining the coefficient of friction of lubricants by changing the temperature of the friction zone in a wide range.

This is achieved by the fact that the inventive device for determining the coefficient of friction of lubricants, containing a movable shaft, on which a guide sleeve is located, a conical guide sleeve, in the hole of which a linear bearing is installed, a counterbody in the form of a conical sleeve in contact with the indenter, the indenter, while the device equipped with an induction furnace located on a conical guide sleeve and isolated from the external environment by means of a conical heat-insulating sleeve fixed with a fixing ring. To control the heating of the contact zone of metal pairs, the device is equipped with a thermocouple formed by chromel-kopel electric wires, the junction of which is located in the indenter hole, and the free ends are connected to a millivoltmeter to record the thermoEMF values.

In order to reduce friction and further prevent misalignment of the guide bush and the tapered guide bush, the device contains linear bearings arranged in two rows in contact with the guide pins.

The difference between this technical solution and the prototype is the fact that using a patented device, it is possible to conduct research to determine the coefficient of friction of lubricants by changing the temperature of the contact zone of metal pairs in a wide range.

The figure shows a structural diagram of a device for determining the coefficient of friction of lubricants in the axial section.

The device for determining the coefficient of friction of lubricants contains a rotating center 1, a movable shaft 2, on which a counterbody is located in the form of a conical bushing 12, a guide bushing 19, a conical guide bushing 41, a thrust nut 3, thrust bearings 4, 22, locking rings 5, 7 , 10, 31, 33, 40, guide pins 6, linear bearings 8, 9, 32, thrust washer 11, the device also contains rolling bearings 14, stop 15, holder 16, pin 17, nozzle 18, 27, spring washer 20, nut 21, thrust ring 23, fixing screws 24, lathe chuck jaws 25, bolt 26, sealing rings 28, 30, CTC feed ring 29, conical heat-insulating sleeve 34, springs 35, 38, indenter 36, induction furnace 37, fixing ring 39, conical electrical wire (chromel) 42, electrical wire (kopel) 43, millivoltmeter 44, electronic dynamometer 13.

The principle of operation of the device is as follows. The movable shaft 2 is fixed at one end by the cams of the lathe chuck 25, and at the other end it is pressed by the rotating center 1, while the indenter 36 is installed in the hole of the movable shaft 2, which is in contact with the counterbody in the form of a conical sleeve 12, while the contact load of the indenter 36 and the counterbody in in the form of a conical sleeve 12 is adjusted by selecting the spring 35, the required stiffness. The spring 35, in turn, is installed in the hole of the movable shaft 2, which is in contact with the indenter 36, which, in turn, is in contact with the counterbody in the form of a tapered bushing 12, installed in the bore of the tapered guide bushing 41. Linear bearings 8 are located on the movable shaft, 32, installed in the hole of the tapered guide bush 41 and the guide bush 19, fixed with locking rings 5, 31, 33, 40. To prevent linear movement of the guide bush 19 and the tapered guide bush 41, thrust bearings 4 are also installed on the movable shaft, 22, fixed with a stop ring 23 and fixing screws 24 on one side and a stop nut 3 on the other. The linear movement of the conical guide bushing 41 is carried out with the help of the thrust nut 3 located on the movable shaft 2, in contact with the thrust bearing 4, and also with the help of the spring 38, in contact with the conical guide bushing 41 through the thrust washer 11.

To prevent warping of the conical guide bushing 41 and the counterbody in the form of a tapered bushing 12, guide pins 6 are installed in the holes of the guide bush 19, fixed with a nut 21 and a spring washer 20, while the guide pins 6 contact with linear bearings 9 located in the conical guide bush 41 and fixed with retaining rings 7.10.

To study the coefficient of friction of lubricants, the supply of STS into the contact zone of the indenter 36 and the counterbody in the form of a conical bushing 12 is carried out using the supply ring STS 29, which contains sealing ring gaskets 30, in turn, the nozzle 27 is installed in the supply ring STS 29 The tightness of the installation of the nozzle 27 in the supply ring of the STS 29 is ensured by means of annular seals 28, also in the movable shaft 2 there is a hole through which the STS in the atomized state enters the nozzle 18 to spray the lubricant into the contact zone of metal pairs.

To prevent the STS from penetrating into the lathe spindle (not shown in the drawing), a bolt 26 is installed on the movable shaft 2.

On the guide pin 6 there is a stop 15 with a pin 17 and rolling bearings 14 installed in it, in contact with the holder 16 installed in the electronic dynamometer 13, with which the torque values are recorded. The device additionally contains an induction furnace 37, which is designed to heat the contact zone of metal pairs formed by the counterbody in the form of a conical sleeve 12 and indenter 36, to study the coefficient of friction of lubricants at different temperatures. To reduce heat dissipation, a conical heat-insulating bushing 34 is located on the conical guide bushing 41, fixed with a fixing ring 39. ) 42 and (kopel) 43, in turn, the free ends of the thermocouple are connected to a millivoltmeter 44 to register the thermoEMF value and determine the temperature according to the corresponding calibration graph. The heating temperature is measured in the static state of the device to determine the operating modes of the induction furnace 37.

The device works as follows: the operation of the device is carried out on a lathe (not shown in the drawing), which provides for the presence of a frequency converter that allows you to adjust the spindle speed in a wide range. The movable shaft is installed in a three-jaw chuck and is pressed by a rotating center. The indenter installed in the hole of the movable shaft contacts with the counterbody in the form of a tapered bushing, and the load of the contact pair is controlled by selecting springs of different stiffness, in turn, the counterbody in the form of a tapered bushing is installed in the hole of the tapered guide bushing containing a linear bearing and a thrust bearing, which allow for rectilinear and rotational movement of the guide conical bushing and the counterbody in the form of a conical bushing, as a result of which it is possible to carry out experimental studies by axial movement of the counterbody in the form of a conical bushing relative to the indenter, using the surface of the counterbody in the form of a conical bushing along the entire length of the generatrix, in its turn, the movement of the conical guide sleeve relative to the indenter is carried out using a thrust nut located on the movable shaft in contact with the thrust bearing, as well as using guide pins connected to the guide sleeve p using nuts and spring washers. The guide sleeve, in turn, contains a linear bearing in contact with the thrust bearing, the axial movement of which is limited by a retaining ring installed with fixing screws. To prevent linear movement of the tapered guide bush, a thrust bearing is provided, which is fixed with a thrust ring and set screws. To transfer the torque from the movable element to the fixed one, a stop is located on the guide pin, containing a pin with installed rolling bearings in contact with the holder installed in the electronic dynamometer. When the movable shaft rotates, the indenter contacts the counterbody in the form of a conical bush, as a result of which a torque is created, which is transmitted to the electronic dynamometer. STS is supplied to the contact zone of the indenter and the counterbody in the form of a conical bushing using a nozzle hermetically installed in the STS supply ring, supplying lubricant during the rotational movement of the movable shaft, due to the presence of sealing ring gaskets in contact with the movable shaft. Further, the STS in the atomized state enters the nozzle through a channel located in the movable shaft. Also, to ensure the tightness of the STS supply system, the use of an additional bolt installed in the movable shaft is provided.

To study the coefficient of friction of lubricants at different temperatures, the device is additionally equipped with an induction furnace located on a conical guide bush and isolated from the external environment using a conical heat-insulating bush, which is fixed with a fixing ring. A thermocouple is installed in the indenter hole, formed by "chromel-kopel" electric wires, the free ends of which are connected to a millivoltmeter, which registers the thermoEMF values. Further, using the calibration table, the heating temperature of the contact zone of metal pairs is determined. Temperature measurements are made in the static state of the device to determine the required modes of operation of the induction furnace.

Claims (1)

A device for determining the coefficient of friction of lubricants, comprising a movable shaft on which a guide bush is located, a conical guide bush, in the hole of which a linear bearing is installed, a counterbody in the form of a conical bush in contact with the indenter, an indenter, characterized in that the device is equipped with an induction furnace, located on a conical guide bushing and isolated from the external environment by means of a conical heat-insulating bushing fixed with a fixing ring, while to control the heating of the contact zone of metal pairs, the device is equipped with a thermocouple formed by Chromel-Kopel electrical wires, the junction of which is located in the indenter hole, and free the ends are connected to a millivoltmeter for fixing the thermoEMF values, the device also contains linear bearings located in two rows, in contact with the guide pins, made with the possibility of axial movement of the conical guide bush.

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