Parametric identification of the mathematical model of the functioning of tribosystems in the conditions of boundary lubrication

The parametric identification of the tribosystem as an object of modeling the functioning of tribosystems in the conditions of boundary lubrication is performed in the work. Using the analysis of the dimensions of significant factors, expressions are obtained to calculate the gain and time constants. It is established that the coefficient takes into account the degree of influence of the load, sliding speed, tribological characteristics of the lubricating medium on the quality factor of the tribosystem. It is shown that the increase in the coefficient will have a positive effect on the processes inherent in tribosystems during operation. Coefficient – characterizes the magnitude of the change in volumetric wear rate and friction coefficient when changing the magnitude of the load, sliding speed, quality factor of the tribosystem. Coefficient – characterizes the ability of the tribosystem to self-organize when changing the values of the input parameters by rearranging the surface layers of materials from which the triboelements are made during secondary running-in. It is shown that the value of the coefficient is large will contribute to the rapid change in the roughness of the friction surfaces, the restructuring of the structure of the surface layers, the appearance of oxidizing films on the friction surfaces (secondary structures). It is proved that the time constant – this is the time required to change the roughness of the friction surfaces and rearrange the structure of the materials of the surface layers when changing external conditions. Time constant characterizes the time during which there is a stabilization of the temperature gradient by volume of triboelements, taking into account the thermal conductivity of materials when changing external conditions. Time constant characterizes the time during which the tribosystem returns to a steady state of operation after the cessation of the outrageous force, or the time to stabilize the parameters in the new mode of operation. It is proved that the value will be optimal for the process of self-organization. It is shown that one of the factors that can control the value , this is the sliding speed

System analysis of friction and wear processes when using fullerene compositions in lubricants

The system-structural approach in researches of processes of friction and wear at application of fullerene compositions in lubricants is proved in the work. It is proposed to use a multilevel approach to study and model the processes of deformation of the surface layers of movable and fixed triboelements and the formation on energy-activated surfaces of wear-resistant structures containing fullerene molecules. The essence of the approach is to use multi-scale research methods to build mathematical models within a single research structure. Due to the fact that tribosystems differ in the integrity of the interconnected elements included in them, it is assumed that all processes occur at three hierarchical levels. At this level, they interact with each other and exchange energy and matter. Input and output flows in studies of tribosystems are formulated. It is shown that the input streams include design parameters of the tribosystem, technological parameters, operating parameters. These parameters form the flow of matter, energy and information, which is the input effect on the tribosystem. The output flow from the tribosystem are the parameters: volumetric wear rate I, dimension m3/hour; friction losses, which are estimated by the coefficient of friction f, dimensionless quantity. The output stream is the information flow of the tribosystem. When solving contact problems, this allows to take into account not only the level of stresses, but also the speed of deformation in the materials of the surface layers, as well as the depth of deformation, which in the models will take into account the volume of deformed material.Depending on the tasks and requirements for their solution, the use of different methodological approaches for modeling is justified. It is shown that the application of mathematical models in the modeling of tribological processes depends on the correct choice of technical constraints that determine the range of optimal solutions

Influence of lubrication on the friction and wear of car rolling bearings

The goal of the work is to develop computational and experimental approaches to determine the wear resistance of friction units with internal contact of cylinders with slip. The scientific novelty consists in taking into account the slip for calculating the friction path and the wear of the cylinders with internal contact and the proposed method for identifying the parameters of the wear law based on the test results. Practical value is the proposed methods to account load, slip and lubrication conditions on the resource for the design of friction units. The dependences for determining the friction path for internal rolling of cylinders have been considered. The design of an experimental setup for studying friction and wear of cylinders with slip has been proposed. Experimental studies have been carried out: paths of friction; wear of surfaces both with a key and without a key; the effect of lubricants on wear has been studied. The form of the wear model is proposed to determine the effectiveness of methods for increasing wear resistance. The method for determining the parameters of the wear law has been implemented based on the test results. The results show the efficiency of copper powder as an additive to a lubricant. It has been established that the wear of cylinders with a key is greater than the wear of cylinders without a key due to different friction paths. A practical example of determining the wear of a car hub shaft using the wear patterns is presented.

Regression analysis of the influence of auger surface hardness on its wear during dehydration of solid waste in a garbage truck

The article is dedicated to the study of the influence of the surface hardness of the auger on its wear during dehydration of solid waste in the garbage truck. Using the method of regression analysis, the logarithmic dependencies of auger wear depending on the hardness of its surface for different values of the friction path are determined. Graphical dependences of augur wear depending on the hardness of its surface for different values of the friction path are made up, and it confirms sufficient convergence of the obtained dependencies. Carried out additional regression analysis allowed to obtain the dependence of wear of the auger depending on the hardness of its surface and the friction path, which showed that during two weeks of operation and wear of the auger during dehydration of solid waste in the garbage truck increasing the surface hardness of the auger from 2310 MPa to 10050 MPa reducing the rate of growth of energy consumption of solid waste dehydration from 16.7 % to 1.5 %, and, consequently, to reduce the cost of the process of their dehydration in the garbage truck. The graphical dependence of the reduction of energy consumption of dehydration of solid household waste due to the increase in the hardness of the auger surface during its two-week wear is presented. It was established the expediency of further research to determine the rational material of the auger and ways to increase its wear resistance

Influence of the parameters of hydrogen nitrogen nitrogen in a glow discharge on tribological and physico-chemical properties of steel 40X

One of the modern and effective methods of hardening metals is nitriding in a glow discharge in ammonia or in an anhydrous medium (nitrogen + argon) - BATR. This paper presents the results of experimental studies comparing the results of tribological and physicochemical properties of hardened surfaces obtained by nitriding with autonomous and interconnected BATR modes. The complex of traditionally fixed values of operating parameters (temperature, composition of the gas mixture, pressure and saturation time) without taking into account energy characteristics (voltage, current density and specific discharge power) significantly reduces the technological capabilities of BATR to achieve the necessary physicochemical properties of metal surfaces specified by conditions exploitation. Taking into account the energy characteristics of BATR, a significant reduction in the energy consumption of the nitriding process is achieved. The energy levels of the main subprocesses are significantly different: the formation of nitrides occurs at low energies, surface sputtering occurs at high voltage values, and nitrogen diffusion occurs at increased current density values. In cases where the energy of the flow is insufficient, either a glow discharge may not occur at all, or with a lack of voltage, the nitride ball on the surface is not sprayed and it acts as a barrier that prevents the diffusion process into the inner layers of the metal, which leads to low physicochemical and, correspondingly, tribological indicators of nitrided balls. The quantitative ratio between them and the required operational properties of the metal, respectively, can be achieved only through an independent combination of the energy and operating characteristics of BATR

Development of methods for evaluation of lubrication properties of hydraulic aviation oils

A method for evaluation of the lubricating and rheological properties of hydraulic oils in tribological contacts has been developed, which consists in online studying samples of commercial batches of oils on a software and hardware complex with visual evaluation of the kinetics of changes in the main tribological indicators of friction contact. Using a roller analogy, the operation of gears in the conditions of rolling with 30% sliding is simulated. Samples of AMG-10 oil from two producers are analyzed. It is established that with increasing temperature of lubricant for Sample 2 (“Kvalitet-Avia” AMG-10), a long-term restoration of protective boundary films of oil is observed and the period of their formation increases by 2.5 times, causing the implementation of a semidry mode of lubrication at start-up. The total thickness of the lubricating layer is 1.27 times less as compared with Sample 1 ("Bora B" AMG-10 oil), regardless of the lubricant temperature. Also, the rheological properties of the oils have been determined. Sample 1 exhibits low shear stresses at the level of 9.4 MPa and high effective viscosity, 4249 and 5039 Pa·s, at a volumetric oil temperature of 20 and 100 ºС, respectively. For Sample 2, with increasing oil temperature to 100 ºC shear stress increases by 1.15 times and the effective viscosity in contact decreases by 1.53 times. Additives present in Sample 1 are characterized by more effective antiwear properties and thus increase the wear resistance of contact surfaces in the conditions of rolling with sliding thanks to strengthening of the surface metal layers during operation, while Sample 2 undergoes strengthening-softening processes which reduce the wear resistance of friction pairs

Influence of filter elements on the operation of tribomechanical systems

Oil filter is a part of a gasoline or diesel engine lubrication system designed to clean the engine oil. Depending on where it is installed, the oil filtration system, they are divided into three types: - through-flow filter, which passes through all the oil that the pump feeds into the engine. A pressure regulating by-pass valve is installed upstream of the filter to protect the gaskets with oil seals. If the filter element is too dirty, the valve directs oil flow past the filter, preventing oil starvation of the bearings. Keeps engine from failing due to lack of lubrication; - a partial-flow filter is mounted parallel to the main oil line and cleans only a portion of the oil that enters the engine. Gradually the whole volume of oil passes through the filter element, giving a fairly high cleaning efficiency. However, this method does not provide absolute protection of parts from chips and other abrasives; - the combination filter combines a full-flow and a partial-flow cleaning principle. It consists of two filter elements, one mounted parallel to the oil line and the other cut into it. This ensures maximum cleaning efficiency and long filter life. The filter elements are divided into two types according to their efficiency in removing fine impurities: coarse filters, which remove coarse impurities, and fine filters, which remove fine impurities. According to the design of the housing and the possibility of replacing the filter element, filters are divided into multiple (collapsible) and disposable (non-collapsible). Modern engines may use filters in the form of a cartridge, which is inserted into a special compartment. During operation, the oil is first routed to the filter and then through the oil channels to the interacting parts in the engine. This principle is used on all standard passenger cars. A settling filter (gravity filter) is a tank with a filter element and a settling tank in which impurities are deposited by gravity. The centrifugal filter operates similarly to the gravity filter, only dirt settles in it under the action of centrifugal force resulting from the rotation of the body

Investigation of tribological characteristics of brake pairs elements of mobile machine

The subject of the experiments was the tribological properties of typical brake pads and disc characteristics. For the experiment was used Grey Cast Iron brake disc and semi metallic, low steel quantity and ceramic brake pads. The breaking process was imitated. The experiment was conducted at 0.75, 1.25 and 1.76 m/s sliding speed using 0.85 MPa contact pressure. The experiments lasted 10 minutes. The results of the experiments showed that best tribological characteristics have ceramic brake pads, despite the fact that brake disc temperature rapidly increase the with ceramic brake pads, but the friction coefficient (and braking torque) was the best. Semi metallic and low steel braking pads had very similar friction coefficient values, but wear and disc temperature values were more dissimila

Research of wear resistance of a covering of shafts of the turbocharger of the diesel engine restored by means of a gas-dynamic spraying

The analysis of tribological researches on the most perspective way of restoration of a primary resource of engines by means of a gas-dynamic spraying is resulted in article. It was found that to reduce the coefficient of friction and increase the wear resistance of the coating is theoretically justified the use of copper-zinc powders brand C-01-11, applied by gas-dynamic spraying. It is established that the physical and mechanical properties of the coatings (roughness, microhardness, friction coefficient) on the restored turbocharger meet the requirements of the manufacturer. The coefficient of friction in the connection, the rotor shaft (reduced powder with copper and zinc), with a plain bearing (made of tin-lead bronze Bros - 10 - 10) is 20 % less than in the connection where the rotor shaft is made of steel 40. The total wear in the bearing assembly with the restored gas-dynamic sprayed rotor shaft is 20 % lower than in the assembly where the rotor shaft is restored by the basic technology. The technology of restoration of a surface of a shaft of a rotor of the turbocompressor, under the bearing of sliding (gas-dynamic spraying) which increases its resource by 23 % in comparison with basic technology of repair of a shaft of a rotor is developed. This allows you to increase its operating time with the established regulatory and technical documentation for overhaul of the engine. A stand for testing diesel turbochargers with recovery technology has been developed, which allows to determine the parameters and characteristics of diesel engine turbochargers in different periods of operation, running-in and adjustment. Tests on the stand showed that turbochargers with restored rotor shafts according to the proposed technology after 2000 operating hours increase all performance by 13 % more than turbochargers repaired by the basic technology. Operational tests have shown that turbochargers repaired using the proposed technology have an operating time of 989 moto-hours more than turbochargers repaired with existing technology

Mathematical modeling of energy loss reduction in gear boxes of oil and gas technological transport

The work is aimed at solving the problem of reducing energy losses in transmission units of hoisting machines for repairing wells. Method of rapid heating and maintaining the optimal temperature in the transmission units of lifting units by using the heat of the exhaust gases was proposed. Analysis of features of a design of transmissions of lifting installations for repair of wells is carried out. Studies of viscosity-temperature characteristics of modern transmission oils and temperature regime in transmission units have been performed. A mathematical model of energy release in transmission units during the operation of lifting units is proposed. Installed energy consumption for friction in the gears of the transmission units. Friction energy losses in bearings of transmission mechanisms of lifting units are determined. A method for reducing energy losses in transmission units of hoisting installations for well repair is proposed. Experimental studies of the implementation of the proposed method of reducing energy losses in transmission units. Dependence of power losses in the gearbox of lifting units depending on the temperature and grade of transmission oil is established. The dependence of power losses in the gearbox of the lifting unit of the UPA 60 / 80 A model depending on the temperature and grade of transmission oil is obtained. The results of calculations of fuel consumption in the gearbox of the lifting unit of the UPA 60 / 80A model with different power drives and at different temperatures of transmission oil are given