RU2766943C1 - Method of determining coefficient of friction of lubricants - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to the field of machine building, namely to methods of studying the coefficient of friction of lubricants of different composition. Method of determining coefficient of friction of lubricants comprises a movable shaft, on which a guide bushing, a guide conical bushing are located, counter-body in the form of a conical bushing, a guide cylindrical bushing, an indenter, linear bearings, guide screws, note here that lubricant process medium (LPM) feed ring with a nozzle installed in it is arranged on movable shaft to feed LPM into contact zone of indenter and counterbody in sprayed state, at the same time, a channel is made in the movable shaft for supplying LPM to the contact zone. Measurement of torque values is carried out using an electronic dynamometer kinematically connected to the guide bushing. In order to reduce friction forces on the movable shaft, linear bearings are installed, which are located in the hole of the cylindrical guide and the guide of bushings.

EFFECT: high accuracy of determining coefficient of friction of lubricating materials and versatility of replacing tested samples, as well as possibility to feed into contact zone of indenter and conical bushing (counterbody) of LPM of animal origin in sprayed state, by free falling jet, as well as by jet under pressure.

4 cl, 1 dwg

Description

The invention relates to the field of mechanical engineering, and in particular 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 - 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.

The closest in technical essence is a device for determining the friction coefficient of lubricants (utility model patent of the Russian Federation No. 203041 IPC G01N 19/02, publ. 19.03.2021. Bull. No. 8. Prototype).

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 guide bushing, a guide conical bushing, a counterbody in the form of a conical bushing, a cylindrical guide bushing, an indenter, linear bearings, guide screws, while the lubricating process medium supply ring is located on the movable shaft (STS) with a nozzle installed in it for the possibility of supplying STS in a sprayed state, while a channel is made in the movable shaft for supplying STS to the contact zone. To prevent rotation of the STS supply ring and the sleeve, a plate is provided, mounted on the end of the STS supply ring, kinematically connected to a fixed base. Torque values are measured using an electronic dynamometer kinematically connected to the guide bush.

The disadvantages of this technical solution are as follows:

1. There is no mechanism that allows supplying heated compressed gas to the contact zone of the indenter and the counterbody, as a result of which the cleaning process of the working area would be qualitatively improved, since the STS of animal origin becomes less liquid during the cooling process and can accumulate in the channels for supplying the STS located in the movable shaft , as well as in the working area;

2. There is no thermostat that allows you to control the temperature of the STS located in the channel for supplying STS;

3. There is no sensor that allows you to control the amount of STS in the crucible;

4. There is no sensor that allows you to control the flow of STS.

The technical result of the invention is the high accuracy of determining the coefficient of friction of lubricants and the versatility of replacing the tested samples, as well as the ability to supply the contact zone of the indenter and the conical bushing (counterbody) with animal-derived CTC in a sprayed state, free-falling jet, as well as a jet under pressure.

This is achieved by the fact that the method for determining the coefficient of friction of lubricants, containing a movable shaft, on which there is a guide bushing, a guide bushing, a counterbody in the form of a tapered bushing, a cylindrical guide bushing, an indenter, linear bearings, guide screws, while measuring the torque values is carried out using an electronic dynamometer, kinematically connected with the guide sleeve, also on the movable shaft there is a ring for supplying a lubricating process medium (STS), containing a nozzle for supplying SFS into the contact zone of the indenter and counterbody, as well as a channel for supplying SFS into the nozzle, while the design equipped with a crucible connected to a channel for supplying STS and located in a housing with a refractory heat-insulating material to accommodate STS, on the outer side of which heat electric heaters are installed, a channel for supplying compressed gas, connected to a nozzle, made with the possibility of mixing compressed gas with a load this STS and the formation of an air-oil mixture.

The difference between this technical solution and the prototype are as follows:

1. The method contains an electric gun connected through a check valve to a channel for supplying compressed gas, as well as to a power supply unit using an electric wire, configured to supply heated compressed gas through a nozzle, through channels located in the movable shaft into the contact zone of the indenter and the conical sleeve (counterbody);

2. The method includes a CTC level sensor located in the crucible, located on the lid, and the device also contains a CTC flow sensor installed in the CTC supply channel;

3. The method contains a thermostat, the thermocouple of which is located in the channel for supplying CTC.

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

The method for determining the coefficient of friction of lubricants, contains a rotating center 1, a movable shaft 2, linear bearings 3, 26, retaining rings 4, 18, 31, 55, guide screws 5, guide bushing 6, rolling bearings 7, pin 8, fixing rings 9 , dynamometer 10, holder 11, indenter 12, sleeve 13, set screws 14, thrust ring 15, lubricant sampling tube 16, thrust bearing 17, gaskets 19, base 20, stop 21, PTFE inserts 22, rod 23, mounting rings 24, cylindrical guide sleeve 25, plate 27, STS feed ring 28, O-rings 29, lathe chuck jaws 30, countersunk head screw with hexagon socket 32, fixing screws 33, 45, nozzle 34, guide sleeve 35, rubber gaskets 36, valve for adjusting the supply of compressed gas 37, channels for supplying compressed gas 38, 42, electric heaters 39, 43, channel for supplying STS 40, valve for adjusting the supply of STS 41, cover 44, gasket 46, housing 47, crucible 48, thermocouples of temperature controllers 49, 58, refractory heat-insulating material 50, temperature controllers 51, 56, switch 52, conical guide bushing 53, conical bushing (counter body) 54, level sensor CTC 57, flow sensor STS 59, check valve 60, hot air gun 61.

The principle of operation of the method is as follows. The indenter 12, mounted perpendicular to the axis of the movable shaft 2, contacts with the conical bushing (counterbody) 54, which is installed in the hole of the guide conical bushing 53 and fixed by means of the guide bushing 6 and guide screws 5, which create a load on the contact pair formed by the indenter 12 and tapered bushing (counterbody) 54. In turn, the guide screws 5 are installed in the guide cylindrical bushing 25, from linear movement of which the thrust bearing 17 and the thrust ring 15, fixed with the set screws 14, prevent linear movement. To reduce friction forces, on the movable shaft 2 are linear bearings 3, 26 installed in the hole of the guide bushing 6 and the guide bushing 25, fixed with retaining rings 4, 18, 31, 55. and nozzle 34, sealed in the hole STS 28 feed ring with the help of a guide sleeve 35 and rubber gaskets 36. In turn, the STS 28 supply ring is hermetically fixed on the movable shaft 2 using sealing ring gaskets 29, ensuring the STS supply to the contact zone during rotation of the movable shaft 2, in which it is also installed countersunk head screw with hexagon socket 32 to prevent CTC from entering the lathe spindle.

For the recycling of used STS, the design provides for the presence of a special sleeve 13, hermetically installed in the guide conical sleeve 53 and the guide cylindrical sleeve 25 with the help of gaskets 19, through which the used STS enters the tube for selecting lubricant 16 for reuse.

The rotation of the movable shaft 2 is carried out using a lathe (not shown in the drawing), which has a frequency converter (not shown in the drawing), which provides adjustment of the spindle speed (not shown in the drawing) in a wide range. Fixation of the movable shaft 2 is carried out using the cams of the lathe chuck 30 and the rotating center 1. To prevent the STS 28 feed ring and the sleeve 13 from turning, a plate 27 is provided, mounted on the end of the STS 28 feed ring using fixing screws 33 and a foot (position in the drawing missing) located on the sleeve 13, on which, with the help of the adjusting rings 24, the rod 23 with fluoroplastic inserts 22 is fixed, in contact with the stop 21 installed in the fixed base 20.

When the movable shaft 2 rotates, the indenter 12 comes into contact with the tapered bushing (counterbody) 54, as a result of which, on the guide bushing 6, a torque occurs transmitted through the tab located on the guide bushing 6 (the position is absent in the drawing), with the installed, using locking rings 9, a pin 8 and rolling bearings 7 located in it, in contact with the holder 11 installed in the dynamometer 10, with the help of which the torque values are recorded. In turn, to supply CTC of animal origin into the contact zone of the indenter 12 and the conical sleeve (counterbody) 54, the design of the method is equipped with a crucible 48 with CTC, which is hermetically closed with the help of a cover 44, a gasket 46 and fixing screws 45, then power is supplied to thermal electric heaters 39, 43 using switch 52. Next, the channel for supplying STS 40 and the crucible 48 with STS are heated. The heating temperature of the STS is controlled using a temperature controller 51, the thermocouple 49 of which is installed on the cover 44, and is immersed in the volume of the heated STS. On the scale of the thermostat 51, the required heating temperature of the STS is set. The molten STS enters through the channel for supplying STS 40 to the nozzle 34, then compressed gas is supplied through the channel for supplying compressed gas 38, as a result of which the STS and compressed gas are mixed in the nozzle 34, forming an aerosol. With the help of a valve for adjusting the supply of compressed gas 37, and a valve for adjusting the supply of CTC 41, the necessary parameters of the air-oil mixture are provided.

To supply STS with a free-falling jet, the supply of compressed gas is blocked using a valve for adjusting the supply of compressed gas 37. To supply STS with a jet under pressure, compressed gas is supplied through the channel for supplying compressed gas 42 into the crucible 48, which displaces the STS. The CTC flow rate is regulated using the CTC 41 flow control valve.

To reduce the heat loss of the heated STS, on the outer part of the crucible 48 there is a refractory heat-insulating material 50, protected from external mechanical action by a housing 47. The method also contains an electric gun 61 connected through a check valve 60 with a channel for supplying compressed gas 38, as well as with a power supply unit with the help of an electric wire (the position is absent in the drawing), made with the ability to supply heated compressed gas through the nozzle 34, through the channels located in the movable shaft 2 into the contact zone of the indenter 12 and the conical sleeve (counterbody) 54. To control the level of the STS located in the crucible 48 , the device contains a STS 57 level sensor located on the cover 44, the device also contains a STS 59 flow sensor installed in the STS 40 supply channel. To control the STS temperature, the device contains a thermostat 56, the thermocouple 58 of which is located in the STS 40 supply channel.

The method works as follows. The movable shaft is installed at one end in the jaws of the lathe chuck, and at the opposite end it is pressed by a rotating center.

The indenter, located perpendicular to the axis of the movable shaft, contacts with a conical bushing (counterbody) installed in the hole of the guide bushing and fixed with the help of the guide bushing and guide screws. The guide screws, in turn, are installed in a cylindrical guide sleeve, the linear movement of which is prevented by a thrust ring located on the movable shaft and fixed with the help of set screws. To reduce the friction forces during the rotation of the movable shaft, linear bearings are installed in the holes of the guide bushing and the guide cylindrical bushing, fixed with locking rings, while a thrust bearing is installed between the end surface of the guide cylindrical bushing and the thrust ring, which also serves to reduce friction forces. The process medium is supplied through the channels located in the movable shaft through the nozzle, which is hermetically installed in the guide sleeve using rubber gaskets, in turn, the guide sleeve is located in the opening of the STS supply ring, where the latter is hermetically installed on the movable shaft using sealing ring gaskets that ensure uninterrupted supply of STS to the contact zone, during the rotation of the movable shaft.

To prevent CTC from getting into the lathe spindle (not shown in the drawing), a countersunk head screw with an internal hexagon is provided, installed in the hole of the movable shaft. For economical use of STS and prevention of equipment contamination, the design provides for the use of a special sleeve hermetically installed on the tapered guide bush and the cylindrical guide bush using sealing gaskets and an installed tube for the selection of lubricant. Also, the design provides for the presence of a special plate installed on the end surface of the STS supply ring using fixing screws and a special tab (no position in the drawing) located on the guide sleeve, to which the rod is attached using adjusting rings, with installed fluoroplastic inserts in contact with the stop , fixed in a fixed base, which serve to prevent the STS supply ring and the sleeve from turning when the movable shaft rotates. To feed into the contact zone of the indenter and the conical bushing (counter body) CTC of animal origin, the CTC is immersed in the crucible and then hermetically sealed with a lid. The tightness of the installation of the cover is ensured by means of a gasket and fixing screws. With the help of a switch, power is supplied to the thermal electric heaters and the crucible with STS and the channel for supplying STS are heated. The heating temperature is controlled by a temperature controller, the thermocouple of which is immersed in the volume of the heated STS located in the crucible. At the moment the required heating temperature of the STS is reached, the molten medium is supplied to the nozzle using a valve to adjust the STS supply, and compressed gas is supplied through the channel for supplying compressed gas, which mixes with the STS in the nozzle, forming an air-oil mixture. The pressure of the compressed gas is regulated using a valve for adjusting the supply of compressed gas and a pressure gauge located on the compressor (not shown in the drawing). To supply STS with a free-falling jet, the supply of compressed gas is blocked, while the valve for adjusting the supply of STS remains in the open position. To supply STS with a jet under pressure, a compressed gas is supplied to the crucible, which ensures the flow of molten STS through the channels for supplying STS to the nozzle. The CTC flow rate is controlled by a cock for adjusting the CTC supply and a CTC flow sensor. The temperature control of the STS is carried out using a thermostat, the thermocouple of which is located in the channel for supplying the STS.

To reduce the heat losses of the heated STS, a refractory heat-insulating material is located on the outer part of the crucible, protected from external mechanical impact by a metal case. When the movable shaft rotates, a torque occurs in the contact pair formed by the indenter and the conical bushing (counterbody), which is transmitted through the guide bushing by means of a kinematic connection to an electronic dynamometer, with which the readings are recorded. Since the STS of animal origin becomes less liquid during the cooling process and can accumulate in the channels for the supply of STS located in the movable shaft and also in the working area, the method contains an electric dryer connected through a check valve to a channel for supplying compressed gas, as well as to a power supply unit when with the help of an electric wire, made with the ability to supply heated compressed gas through the nozzle, through the channels located in the movable shaft into the contact zone of the indenter and the conical bushing (counter body), as a result of which the process of cleaning the working zone from the spent STS is qualitatively improved.

Claims (4)

1. A method for determining the coefficient of friction of lubricants, containing a movable shaft on which a guide sleeve, a guide conical bush, a counterbody in the form of a conical bush, a cylindrical guide bush, an indenter, linear bearings, guide screws are located, while the measurement of torque values is carried out using electronic dynamometer, kinematically connected with the guide bush, also on the movable shaft there is a ring for supplying a lubricating process medium (STS), containing a nozzle for supplying SFS into the contact zone of the indenter and counterbody, as well as a channel for supplying SFS into the nozzle, while the structure is equipped with a a channel for supplying STS and a crucible located in a housing with refractory heat-insulating material for accommodating STS, on the outer side of which thermal electric heaters are installed, a channel for supplying compressed gas connected to a nozzle, made with the possibility of mixing compressed gas with heated STS and forming air-oil mixture. 2. The method for determining the coefficient of friction of lubricants according to claim 1, containing an electric gun connected through a check valve to a channel for supplying compressed gas, as well as to a power supply unit using an electric wire, configured to supply heated compressed gas through a nozzle, through channels located in the movable shaft into the contact zone of the indenter and the conical bushing (counter body). 3. The method for determining the coefficient of friction of lubricants according to claim 1, containing a CTC level sensor located in the crucible, installed on the crucible lid, and the device also contains a CTC flow sensor installed in the CTC supply channel. 4. The method for determining the coefficient of friction of lubricants according to claim 1, containing a thermostat, the thermocouple of which is located in the channel for supplying the STS, made with the ability to control the heating temperature of the STS.

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