RU203922U1 - 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. A device for determining the coefficient of friction of lubricants containing a movable shaft on which a thrust nut, a tapered guide sleeve, guide pins, a counterbody in the form of a tapered sleeve are located , an indenter, a guide sleeve, where an indenter is installed in the hole of the movable shaft, with the ability to contact one end with a counterbody in the form of a tapered sleeve, and the other with a spring serving 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 technological medium (STS) in a sprayed state directly to the contact zone of metal pairs. To register the torque, an electronic three-component dynamometer M30-3-6k was used, connected to a PC, which makes it possible to increase the accuracy of measuring the coefficient of friction of lubricants. To study the magnitude of the thermo-EMF in the friction zone by the method of a naturally forming thermocouple, the device contains an ebonite disk on which a metal a disk for the transfer of thermo-EMF, interacting with the current collector by means of a spring installed in a metal bushing, providing reliable electrical contact, while an ebonite tapered bushing is installed between the tapered guide bush and the tapered bushing (counterbody), providing electrical insulation between them, for the same purpose an ebonite bushing is installed between the indenter and the movable shaft, where the transfer of thermo-EMF from the indenter and the tapered bushing (counterbody) is carried out using electric wires, the free ends of which are immersed in a container with ice and connected to a millivoltmeter that records the values of thermo-E DS: 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 the possibility of studying the temperature parameters of the friction process. 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 different composition.

A device for testing rubbing materials and oils is known (USSR AS No. 983522, IPC G01N 19/02. A device for testing rubbing materials and oils. Bull. No. 47, 1982 Analog), containing a frame, sample holders installed on it and a counter-sample, units for measuring the moment of friction and loading of samples and a drive for rotation of samples, a plate installed perpendicular to the frame with the ability to move 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 platforms and interacting with the counter-specimen holders, guide and pressure rollers mounted on the plate with the ability to rotate in the plane of the holders, transmission links interacting through rolling bearings, respectively, with the counter-specimen holders and loading units, and the latter are equipped with rods having two degrees of freedom (mechanisms to transfer the load to the counter-samples).

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

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

All friction units are driven by the drive output shaft through gears. The frictional moment in the “disc-indenter” pair is measured by an elastic tensometric beam. Electrical signals are fed to two strain gauge transducers, from which they are transmitted to a 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 at the contact of the indenter and the disk.

A device for determining the coefficient of friction of lubricants is known (patent for a useful model of the Russian Federation No. 192398 IPC G01N 19/02, publ. 09/16/2019. Bull. No. 26. Analogue), containing a base for installing the device, a stationary shaft with an indenter, a sleeve with a tapered bore (countertelo), fluoroplastic bushing, loading (fixing) screws, thrust washer, 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 stationary shaft of the device and a sleeve with a tapered hole is installed. With the help of loading (fixing) screws, pressure is created on the contact pair and controlled with a torque wrench, then the lever is installed on the bushing, 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 arising from the rotation of the indenter is transmitted by means of a lever to the measuring device, according to the indications of which the friction coefficient is determined.

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

The closest in technical essence is a device for determining the coefficient of friction of lubricants (patent for a useful model of the Russian Federation No. 200035 IPC G01N 19/02, publ. 01.10.2020. Bul. No. 28. Prototype), containing a movable shaft on which a thrust nut is located , tapered guide bush, guide pins, counterbody in the form of a tapered bushing, indenter, guide bushing, where a half indenter is installed in the hole of the movable shaft, with the ability to contact one end with the counterbody in the form of a tapered bushing, and the other with a load spring serving to create the required 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 technological medium (STS) in a sprayed state directly to the contact zone of metal pairs. To register the torque, an electric three-component dynamometer M30-3-6k, connected to a PC, was used, which makes it possible to increase the accuracy of measuring the coefficient of friction of lubricants. To reduce the friction that occurs when the tapered guide bush and the guide bush come into contact with the movable shaft, linear bearings are located in the holes of the tapered guide bush and guide bush, which are fixed with retaining rings.

The disadvantages of the known device is the inability to study the temperature arising in the contact zone of the indenter and the counterbody in the process of friction.

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 through the possibility of studying the temperature parameters of the friction process.

This is achieved by the fact that the inventive device for determining the coefficient of friction of lubricants, containing a movable shaft, a thrust nut, a tapered guide bushing, guide pins, a counterbody in the form of a tapered bushing, an indenter, a guide bushing contains an electrical adapter, which is an ebonite disk fixed on the end of the thrust nut with the help of fixing screws, in turn, to the end of which a metal disk is installed for the transfer of thermo-EMF (arising in the friction zone by the method of a naturally forming thermocouple), interacting with the current collector by means of a spring installed in a metal sleeve, providing reliable electrical contact , in this case, an ebonite conical bushing is installed between the tapered guide bushing and the tapered bushing (counterbody), providing electrical insulation between them, for the same purpose, an ebonite bushing is installed between the indenter and the movable shaft. The transfer of thermo-EMF from the indenter and the tapered sleeve (counterbody) is carried out using electric wires, the free ends of which are immersed in a container with ice in order to increase the potential difference of the natural thermocouple and are connected to a millivoltmeter that records the values of thermo-EMF.

The difference between this technical solution and the prototype is the fact that with the help of the patented device it is possible to investigate the temperature in the friction zone of the tapered sleeve (counterbody) and the indenter by the method of a naturally forming thermocouple.

FIG. the structural diagram of the device for determining the coefficient of friction of lubricants in the axial section is presented.

The device for determining the coefficient of friction of lubricants contains a movable shaft 1, a thrust nut 2, a rotating center 3, thrust bearings 4, 15, linear bearings 5, 14, a tapered guide bushing 6, guide pins 7, a tapered bushing (counterbody) 8, springs 9 , 36, 12, indenter 10, nozzle 11, guide sleeve 13, set screws 16, thrust ring 17, chuck jaws 18, bolt 19, CTC feed ring 20, rubber gaskets 21, spray 22, adapter 23, O-rings 24 , holder 25, dynamometer 26, stud 27, rolling bearings 28, ebonite tapered bushing 29, ebonite bushings 30, 35, fixing screws 31, ebonite disc 32, metal disc 33, current collector 34, metal bushing 37, clamps 38, ice container 39, electrical wires 40, 41, millivoltmeter 42.

The principle of operation of the device is as follows. The movable shaft 1 is fixed at one end by the cams of the lathe chuck 18, and at the other end it is pressed by the rotating center 3, while the indenter 10 is installed in the hole of the movable shaft 1, which is in contact with the tapered bushing (counterbody) 8, while the contact load of the indenter 10 and the tapered bushing ( counterbody) 8 is adjusted by selecting a spring 9 of the required stiffness, which is installed in the hole of the movable shaft 1, in contact with the indenter 10, between which there is an ebonite gasket (the position in the drawing is not indicated), for electrical isolation of the indenter 10 from the movable shaft 1, in in turn, the tapered bushing (countertelo) 8 is installed in the tapered guide bushing 6, which contains the linear bearing 5 and the thrust bearing 4, in turn, the tapered guide bushing 6 is mounted on the movable shaft 1, and the guide bushing 13 is also installed on the movable shaft 1, which contains a linear bearing 14, a thrust bearing 15 and guide pins 7, which are in contact with the guide holes located in the tapered guide sleeve 6, a thrust ring 17 is also installed on the movable shaft 1, which prevents linear movement of the guide sleeve 13, during linear movement of the tapered guide sleeve 6 with springs located in the guide pins 7 and contacting the guide sleeve 13 12, in turn, the thrust ring 17 is fixed on the movable shaft 1 by means of set screws 16. The linear movement of the tapered guide sleeve 6 is carried out using the thrust nut 2 located on the movable shaft 1. The STS is fed into the contact area of the indenter 10 and the tapered sleeve ( counterbody) 8 is carried out using a ring for supplying CTC 20, which contains O-ring gaskets 24, in turn, the sprayer 22 is installed in the supply ring of CTC 20 using an adapter 23, and the tightness of the installation of the sprayer 22 in the hole of the adapter 23 is provided by rubber gaskets 21, also in p the movable shaft 1 has a hole through which the STS in the sprayed state enters the nozzle 11 mounted on the movable shaft 1, on the opposite side of which, in turn, a bolt 19 is installed to prevent the STS from penetrating into the lathe spindle (not indicated in the drawing) ... On the tapered guide sleeve 6 there is a tab with a pin 27 and rolling bearings 28 installed in it, which contact the holder 25 when the tapered guide sleeve 6 rotates, in turn, the holder 25 is installed in the dynamometer 26, with which the values of the friction coefficient are recorded.

To study the magnitude of the thermo-EMF in the friction zone, using the naturally forming thermocouple method, the device is equipped with an ebonite tapered bushing 29 installed in a tapered guide bushing 6, which provides electrical insulation of the tapered bushing (counterbody) 8, connected by an electric wire 41 with a millivoltmeter 42, in turn, an indenter 10 It is also isolated from the movable shaft 1 by means of an ebonite sleeve 30, and connected to a millivoltmeter 42 using an electric wire 40, while for the transfer of thermo-EMF from the indenter 10 to the millivoltmeter 42, the device is equipped with an electric adapter, which is an ebonite disk 32 fixed on a thrust nut 2 by means of fixing screws 31, on which a metal disk 33 is also fixed, connected to the indenter 10 by means of an electric wire 40 and transmitting thermo-EMF to a metal current collector 34, permanent contact of which is provided by means of a spring 36 installed in a metal sleeve 37. For electrical insulation current collectors ka 34, an ebonite bushing 35 is installed in a metal bushing 37. A metal bushing 37 with a spring 36, an ebonite bushing 35 and a current collector 34 are installed on the stationary part of the rotating center 3 using clamps 38. In order to increase the potential difference of the natural thermocouple, the ends of the electric wires 40 and 41 are immersed in container with ice 39. The obtained thermo-EMF values are converted into temperature values using the appropriate calibration schedule.

The device works as follows: the device is operated on a lathe (not indicated in the drawing), which provides for the presence of a frequency converter, which makes it possible to adjust the spindle speed in a wide range. The movable shaft is installed in a three-jaw chuck and is pressed by the rotating center. The indenter installed in the bore of the movable shaft is in contact with the tapered bushing (counterbody), and the load of the contact pair is adjusted by selecting springs of different stiffness, in turn, the tapered bushing (counterbody) is installed in the bore of the tapered guide bush, containing a linear bearing and a thrust bearing, which allow for rectilinear and rotary movement of the guide tapered bushing and tapered bushing (counterbody), as a result of which it is possible to carry out experimental studies by axial displacement of the tapered bushing (counterbody) relative to the indenter, using the surface of the tapered bushing (counterbody) along the entire length of the generatrix, in turn , the movement of the tapered guide bush relative to the indenter is carried out by means of a thrust nut located on the movable shaft in contact with the thrust bearing, as well as by means of guide pins connected to the guide bush. For more accurate positioning of the tapered bushing (counterbody) relative to the indenter, springs located on the guide pins are additionally used between the guide bush and the tapered guide bush. The guide bush, in turn, contains a linear bearing, and to prevent linear movement of the tapered guide bush, a thrust bearing is used, fixed with a thrust washer and set screws. In turn, a special foot is located in the tapered guide sleeve, with a pin fixed to it, on which the rolling bearings are installed, in contact with the holder installed in the dynamometer. When the movable shaft rotates, the indenter contacts the tapered bushing (counterbody), as a result of which a torque is generated, which is transmitted through the tab with the pin located in it to the holder installed in the dynamometer, with which the readings are recorded. The STS is fed into the contact area of the indenter and the tapered bushing (counterbody) using a spray gun hermetically installed in the adapter using rubber gaskets, in turn, the adapter is installed in the STS feed ring, with the help of which the STS is fed during the rotational movement of the movable shaft, thanks to the presence of O-ring gaskets, then the STS in the sprayed state enters the nozzle through the channel located in the movable shaft. Also, to ensure the tightness of the STS supply system, the use of an additional bolt is provided.

To study the magnitude of the thermo-EMF in the friction zone, by the method of a naturally forming thermocouple, an ebonite tapered bushing is installed in the device, which provides electrical insulation between the tapered guide bushing and the tapered bushing (counterbody), where the latter is connected with an electric wire to a millivoltmeter, to which an indenter isolated from the movable shaft using an ebonite bushing. The thermo-EMF values are transmitted from a moving element to a stationary one using an electrical adapter containing an ebonite disk with a metal disk fixed at the end in contact with a current collector, the constant electrical contact of which is provided by a spring installed in a metal bushing, while electric wires in contact with a tapered bushing (counterbody) and with an indenter with their free ends immersed in a container with ice and connected to a millivoltmeter, with which the thermo-EMF values are recorded.

Claims (1)

A device for determining the coefficient of friction of lubricants, containing a movable shaft, a thrust nut, a tapered guide bushing, guide pins, a counterbody in the form of a tapered bushing, an indenter, a guide bushing, characterized in that the device contains an ebonite disk on which a metal disk is installed for transferring thermal - EMF interacting with the current collector by means of a spring installed in a metal bushing, providing reliable electrical contact, while an ebonite conical bushing is installed between the tapered guide bush and the tapered bushing (counterbody), providing electrical insulation between them, for the same purpose, an ebonite bushing is installed between an indenter and a movable shaft, where the transfer of thermo-EMF from the indenter and the tapered bushing (counterbody) is carried out using electric wires, the free ends of which are immersed in a container with ice and connected to a millivoltmeter that records the values of thermo-EMF.

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