Sleeve Bearings Research Articles

Research on Working Mechanism and Structural Optimization of High-Speed Bearing of Tricone Bits Based on Finite Difference Method

Abstract To analyze the working mechanism of the floating sleeve bearing of the cone bit, the life of the floating sleeve bearing was tested. The experimental results show that adhesive wear will form on the bearing surface with the increase in temperature, which is the main cause of bearing failure. This article establishes the Reynolds equation and energy equation of the oil film based on the theory of dynamic pressure lubrication of sliding bearings. The equation was numerically solved based on the finite difference method. It determines the rotational speed ratio at the equilibrium based on the trend of the frictional torque and then corrects the eccentricity in the iterative calculation process so as to analyze the tribological performance of the bearings in equilibrium under different clearance ratios. Among them, the improper configuration of the internal and external clearance ratio leads to the increase of the friction torque and the reduction of the bearing capacity. For floating sleeve bearings, the configuration with a large internal clearance and small external clearance should be adopted. Finally, the bearing structure is optimized and numerical calculations show that the tribological performance of the new type of bearings is significantly improved compared with that of ordinary cone bit bearings.

A New Approach to Prevent Injuries Related to Manual Handling of Carts: Correcting Resistive Forces between Floors and Wheels to Evaluate the Maximal Load Capacity

Test methods that use pushing forces to evaluate the maximal load capacities of carts in design standards require a flat, smooth and horizontal steel plate and thus do not take into account the real conditions of work. Resistive forces of a single wheel of a cart in a uniform rectilinear motion were measured using a unique test bench with five loads. Forty-four wheels were tested (varying diameters, treads and bearings) with one steel plate and four resilient floor coverings. Based on a linear mixed model, all the following results were significant (p < 0.05). Resistive forces were increased linearly with the load and depended on the characteristics of both the wheel and floor. These forces decreased as the diameter increased. They were important for wheels with sleeve bearings but decreased for cone ball bearings and precision ball bearings. Resistive forces depended on the material of the tread and were higher for solid rubber treads. In contrast, the hardness of the tread had little effect. Resistive forces strongly depended on the hardness of the base foam of resilient floor coverings: the softer the base foam, the higher the resistive forces. Test methods in design standards should be reviewed, using corrective forces based on these present results, to prevent musculoskeletal disorders.

Evaluation Model for Bearing Capacity of Grouting Sleeves Based on Conventional Material Parameters

The existing bearing capacity model for grouting sleeves is synthesized in this study. Utilizing the principles of thick-walled cylinders in elastic mechanics, a comprehensive ultimate bearing capacity model for grouting sleeves is developed using conventional material parameters. To validate the efficacy of the model, 18 steel bar grouting sleeves of varying anchor lengths, steel bar diameters, and designs were tested. The outcomes indicate minimal errors in the computational results and demonstrate superior applicability when juxtaposed with established grouting sleeve bearing capacity formulas.

Cost-Effective Design Modification of a Sleeve Bearing with Large Bearing Clearance

In 2015, a 45 MW vertical hydropower machine exhibited excessive vibration after refurbishment. Measurements revealed a substantial bearing clearance at the lower generator guide bearing. Consequently, the bearing was unable to generate sufficient opposing force to drive the rotor toward the bearing center, resulting in more pronounced overall system vibration. Addressing this challenge required a cost-effective and feasible solution for mitigating the vibration problem. To this end, a design modification was implemented wherein the lower generator guide bearing (originally a sleeve bearing) was modified to a four-lobe bearing by offsetting the two halves of the bearing twice in two axes. Numerical simulations and experimentations were conducted, and the dynamics of the machine before and after the design modification were investigated. Both the simulation and experimental results showed that the machine with the four-lobe bearing improved the system stability and reduced the vibration amplitudes. The numerical simulation result demonstrated that, due to the design modification, the first and second critical speeds were effectively eliminated for a speed range of up to three times the nominal speed. Furthermore, for nominal operation with unbalanced magnetic pull, the four-lobe bearing provided a stability advantage in terms of the modal parameters relative to the original sleeve bearing.

Finite Element Analysis of Sleeve Bearing Housing Based on Abaqus

Finite Element Analysis of Sleeve Bearing Housing Based on Abaqus

DEVELOPMENT OF A MATHEMATICAL MODEL FOR ANALYZING THE ECONOMIC EFFECT OF THE MODIFIED DESIGN OF A RADIAL SLIDING BEARING AND ITS PREDICTION

In modern heavy-loaded friction units, various types of antifriction coatings are used on the surface of the bearing profile of the bearing sleeve to ensure high load-bearing capacity and increase the duration of the hydrodynamic regime, and consequently, the economic effect of sliding bearings.
 In the study, the creation and development of mathematical models of a radial sliding bearing with an antifriction polymer coating of the support surface containing a groove is carried out. The key role here is played by the method of analytical forecasting, which determines the mechanism of friction and the conditions for its transition from boundary to liquid.
 The aim of the study is to develop a mathematical model of a radial sliding bearing with a polymer coating of the bearing sleeve bearing surface containing an axial groove to predict the economic effect.
 The objective of the study is to develop new mathematical models and analyze the movement of lubricant in the working gap of a radial sliding bearing, taking into account design features to predict the economic effect.
 The difference from the existing models of tribosystems with antifriction coatings is the presence of a groove, which ensures stable ascent of the shaft on the hydrodynamic wedge and reduces wear during start-up and run-outs, hence increasing the service life of tribosystems.
 Using the lubricant motion equation and the continuity equation, new mathematical models are obtained that take into account the design features of the bearing sleeve surface – polymer coating, groove width, rheological properties of the lubricant used. Based on the results of an experimental study on the AI 5018 friction machine, the economic efficiency of net discounted income was calculated on samples in the form of partial inserts.
 As a result of the research, new mathematical models for engineering calculations have been developed that allow predicting the efficiency, reliability and duration of the hydrodynamic lubrication regime, as well as determining the main tribotechnical parameters. Net discounted income based on the results of theoretical and experimental research is estimated at 0.36 million rubles per year.

Experimental study on the compression-shear performance of a new-type circumferential joint of shield tunnel

To investigate the compression-shear behavior of a new circumferential joint based on the sleeve-straight bolt combination type connection of large-diameter shield tunnels, a series of full-scale joint experiments was carried out. In the process of the experiment, more attention was paid to the specimen displacement, bolt stress and joint damage mode. On the basis of these experiment phenomena, this study discussed the compression-shear bearing process of the new connector, analyzed the damage mode of the joint structure, and finally evaluated the performance of the new connector. It is found that the bearing process of the joint can be divided into four stages: the transitional stage for overcoming the friction of the concrete, the sleeve bearing stage for the sleeve bearing shear loads alone, the combined bearing stage for bearing shear loads by the connector system, and the structural damage stage for structural instability and damage. Generally speaking, affected by connector position and hand hole, the positive compression-shear stiffness of the joint is less than the negative compression-shear stiffness, and the positive shear strength of the joint is greater than the negative shear strength. The increase of longitudinal axial force will improve the compression-shear performance of the joint. The relationship between longitudinal axial force and joint stiffness is a logarithmic function. The use of new type of connector can effectively improve the compression-shear stiffness of joints under low shear loads, but the application of straight bolts will lose part of the strength performance.

Revealing the effect of changing the operating parameters of a double hydrostatic bearing on its characteristics

The object of research is hydrostatic processes in sliding bearings with several layers of lubricant. The task addressed was the influence of the structural and operational parameters of dual hydrostatic plain bearings on their static and dynamic characteristics. As a static characteristic, the bearing capacities of dual and conventional sleeve hydrostatic bearings were considered. When analyzing the dynamic characteristics, the amplitude-frequency characteristics were determined. They were obtained by calculation and as a result of experimental studies. When calculating the amplitude-frequency characteristics, the trajectory method was used. As external forces in the equations of motion of the rotor, hydrodynamic forces, the weight of the rotor, and its unbalance were considered. Experimental determination of the trajectories of the rotor was carried out on a special bench. It has been established that the bearing capacity of a double type bearing is approximately 1.75–1.85 times higher than the bearing capacity of a conventional sleeve bearing. The range of stable operation of the rotor on double-type bearings is approximately 1.4 times greater in comparison with the range of stable operation of the rotor on sleeve hydrostatic bearings. The vibration amplitudes in the resonance region for double bearings were approximately 1.5 times less than the rotor vibration amplitudes for sleeve bearings. The results make it possible to recommend dual-type hydrostatic bearings for rotor bearings of nuclear power plants, in powerful aircraft engines with a gearbox, various types of pumps, and other power plant units. The derived theoretical dependences make it possible to carry out practical calculation of hydrostatic bearings of a double type

Design model of radial bearing with bearing sleeve elastic bearing profile and metal coated shaft surface

The article is devoted to the development and analysis of a design model of lubricant movement in the working gap of a radial journal bearing with an elastic bearing profile of the bearing sleeve surface and a metal coating of the shaft surface with truly viscous properties. New mathematical models have been developed based on basic equations that take into account the flow of a truly viscous liquid for a “thin layer”, the malleability of the bearing sleeve support surface - the Lame equation, compressibility - the equation of state, the Weisbach - Darcy formula, the profile of the molten contour of the metal coating of the shaft surface - the rate of dissipation of mechanical energy. The results of the numerical analysis of the refined models obtained by changing the design of the radial bearing, as well as taking into account the compressibility of the lubricant and the coating melt, allowed us to obtain an effectiveness qualitative assessment of the malleable bearing profile of the bearing sleeve and the shaft with a metal coating. A comparative analysis of the obtained results of theoretical and experimental studies of radial bearing structures: with and without metal coating; elastic support profile; without taking into account the elasticity of the support profile; taking into account compressibility; without taking into account the compressibility of the lubricant. At the end of the research complex, experimental tests were carried out that confirmed the correctness of the results of theoretical studies. The ingenuity of the developed design models, taking into account the use of additional lubrication with a metal coating on the shaft surface to compensate for an emergency shortage of lubricant, the compressibility of the lubricant, as well as the malleability of the bearing surface, consists in the application of a technique for obtaining their exact self-similar solutions. As a result of theoretical, experimental research and comparative analysis of the available scientific results with the obtained ones, it was found that the use of the studied radial journal bearings, taking into account the above factors, significantly increases the bearing capacity (8-9 %), and the coefficient of friction decreases by 7…8 %.

Tribotechnical Properties of Materials for Cultivator Sliding Bearings

Agricultural machinery is stated to break down mainly due to the wear of structural parts. Thus, there is a necessity to apply new materials for manufacturing individual machine units whose characteristics will not be inferior to those of their prototypes. The paper primarily focuses on the components that work in movable joints, in particular, on the sleeve type bronze plain bearings which are exposed to high wear and often need replacing. The use of polymers for manufacturing such parts is supposed to solve the problem of untimely failure of machine components. (Research purpose) To compare the tribotechnical properties of cultivator sliding bearings made of bronze and polyamide. (Materials and methods) Two samples were made: one was made of the sliding bearing (BrO10F1 grade bronze) of the SunGarden GT10 cultivator, the other – of a PA-6 polyamide type rod. Special equipment was used such as: X-ray fluorescence spectrometer Thermo Scientific Niton XL3t 900 GOLDD+, TRB-S-DE Tribometer CSM Instruments. (Results and discussion) Comparative tribotechnical ball-disk tests were carried out. It was found out that polyamide sample has certain advantages over a bronze standard: it has a 4-times better friction coefficient and a 12-times better wear intensity. (Conclusions) It was determined that the use of polymer plain bearings will result in 2 times longer service life of agricultural cultivators and their 1.5 times increased efficiency.

INVESTIGATION OF THE EFFECT OF TITANIUM NANO PARTICLES ADDITIVES IN PHOSPHOR BRONZE COMPOSITE FOR WEAR APPLICATIONS

An investigation was carried out to assess the mechanical properties of phosphor bronze composite with addition of titanium nano particles. Phosphorous bronze composite main application is used to manufactured sleeve bearings and cam followers. The main objective of this paper is to study the effect of Titanium nano particles which improved strength and wear resistance. In this study, a series of mechanical experiments is done on casted phosphor bronze with blended titanium nano particles with varying percentage of compositions in nano titanium. The strength, hardness, Impact and wear properties are compared among them by varying titanium nano Particles. KEY WORDS: Nano Titanium, phosphor Bronze, Wear Resistance, Radio frequency (RF) induction coupled plasma technique

Experimental investigation of vibration damping capabilities of 3D printed metal/polymer composite sleeve bearings

Additive Manufacturing (AM) method enables to produce products easily, cheaply and quickly with more complex geometry compared to traditional production methods. In this context; Fused Deposition Modeling (FDM) is a widely used for AM method that requires a large number of process parameters. In this study, it is aimed to experimentally investigate the damping capabilities of the metal/polymer composite sleeve bearings printed using FDM. A total of 54 pieces (27 pairs) were printed from composite filaments such as nine pairs for each of PLA, PLA + 20% Bronze, and PLA + 20% Copper metal/polymer with different filling structures (Octogram spiral, Archimedian chords, and 3D Honey comb) and different occupancy rates (10, 30, and 50%), respectively. The experiments were carried out using the shaft-bearing system under the same operating conditions at a rotational speed of 900 revolution per minute (rpm), and vibration data was collected from the rotating shaft with proxy probes. Rotating shaft position is very important to determine journal position in bearing for understanding deterioration in the bearing. Bode and Orbit plots are used to detect the level of deterioration in the bearing. The value of bearing to shaft clearence can vary widely depending on application. Since the bearings were heavily loaded, they were compressed by radial load caused large clearence. The results showed that compressed bearing had significant influence on the stability of rotating shaft system and significant differences in damping capabilities of composite sleeve bearings with different filling structures and occupancy rate. Increasing occupancy rate decreases the vibration amplitude values in copper-reinforced sleeve bearing but increases in bronze-reinforced sleeve bearing. From the microstructure analysis, it has been observed that the vibration absorbation capability is better due to the more homogeneous distribution of the copper reinforced bearings than the bronze reinforced bearings. Also, vibration absorption capability of sleeve bearings with 3D Honeycomb filling structureis increased significantly proportion to the occupancy rate.

Determining the influence of structural and operational parameters of a double bearing on the thickness of its disc

This paper describes the main advantages of hydrostatic dynamic bearings of the double type, which have several lubricant films. It is indicated that they have an increased carrying capacity, by 1.8 times, and an extended range of stable operation, by 1.5 times, compared to conventional sleeve bearings with one lubricating film. The importance of determining the thickness of the bearing disk has been demonstrated, as it affects its durability. The goal was to investigate the impact of changes in the operational and structural parameters of a double bearing on the thickness of its disk. A sequence for determining the disk thickness has been proposed, including a joint solution to Reynolds equations, the balance of work fluid flow rate, as well as determining the loads acting on a bearing disk, which makes it possible to rationally assign the thickness of the bearing disk. The most common and effective methods of successive approximations have been used in the numerical implementation of Reynolds equations and flow rate balances. The action of centrifugal forces caused by the rotation of the disk has been taken into consideration in determining the total load acting on the bearing disk. The bending strength of the bearing disk was considered under its exposure to the total load. It was noted that due to the high flow rate of the working liquid pumped through the bearing, and the small change in the temperature of the liquid inside the bearing, the temperature deformations of the disk were not taken into consideration. The magnitude of change in the thickness of the double bearing disk has been determined, caused by the action of centrifugal forces in the examined range of angular speeds of the disk's rotation with the shaft. The reported results could be especially useful in the design of rotor supports for nuclear power plants where bearings have large dimensions, as well as for other units in power plants.

Lubrication performance analysis of multi-groove sleeve bearing considering journal misalignment

PurposeUnder the influence of loading, manufacturing, installation and other factors, the axis of sleeve bearing and journal will not be aligned, which will have a great impact on running stability and life of bearing. The existence of oil groove can effectively improve the life of sleeve bearing and working efficiency. The lubrication performance of two and three grooves sleeve bearing considering journal misalignment is analyzed.Design/methodology/approachTo solve the difference of discontinuous position of oil film thickness, it is necessary to use the flow balance relationship in the finite control space, and oil film thickness equation of multi-groove sleeve bearing considering journal misalignment is gained.FindingsThe friction and bearing capacity of journal bearing with oil groove increase with the increase of journal inclination angle. At the same journal inclination angle, the bearing capacity of two-axial groove journal bearing is larger than that of three-axial groove journal bearing, but the friction of two-axial groove journal bearing shows the trend of the first bigger and then smaller than that of three-axial groove journal bearing.Originality/valueThe research has great significance to optimize bearing lubrication performance and increase bearing working life.

Tribological behavior of ceramic-alloy bearing contacts in molten salt lubrication for concentrating solar power

Molten salts are considered as candidate heat transfer fluids and thermal energy storage media for next generation concentrating solar power (CSP). A molten salt circulates inside the piping and heat exchanger and also functions as a lubricant for the sleeve bearings of the CSP pump. Wear- and corrosion-resistant high-temperature bearing materials are critical for the pump efficiency and durability. This study evaluated the tribological performance of candidate bearing materials in lubrication of a molten chloride salt mixture (20% NaCl + 40% MgCl2 + 40% KCl) at 750 °C in an inert argon gas (a simulative CSP pump environment). Six ceramic-alloy pairs were tested, zirconia and silicon nitride against Haynes 244, Hastelloy C276, and Tribaloy T900 alloy, and ranked by the friction coefficient and wear loss. Characterization of worn surfaces suggested the wear mechanism as a combination of abrasion, adhesion, and tribocorrosion. Results from this study provide fundamental insight for the development and selection of bearing materials for molten salt powered CSP pumps.

Ensuring accuracy in the electromechanical processing of parts holes with a high-temperature strip source

Тhe accuracy of the holes in the electro - mechanical processing with a high-temperature strip tool is achieved by the development of original tooling. The article presents technical solutions of tool and technological equipment to ensure the accuracy of holes in the implementation of processes of electromechanical processing with a high-temperature strip source. The results of measurements on cylindricality of the hole of the sleeve bearing of the upper head of the connecting rod of the Yaroslavl Engine Plant engine after volumetric electromechanical mandrel are presented, confirming the effectiveness of using the developed tooling.

АНАЛИЗ ОСОБЕННОСТЕЙ МОДЕЛИРОВАНИЯ ПРОЦЕССОВ В ТОПЛИВНЫХ ШЕСТЕРЕННЫХ НАСОСАХ ГТД

The article touches upon the issues of the operating process in the elements of the external gear pump modeling. The external gear pump is the part of the gas turbine engine and pumps a low-viscosity fluid – kerosene. The article shows that sleeve bearings in such pumps continue to operate at boundary friction modes while rotation speed is increased. It also shows that the end and radial clearances are variable, and the drain system is not optimal which prevents the modeling of the system by classic approach. The main elements of the pumping unit of the external gear pump are described in the article. A simplified geometric model, which forms the basis for the analysis of the pump operation, is given as well. The problems arising during the design stage, fine-tuning, and operation of external gear fuel pumps are briefly described. A preliminary analysis of the design methods showed that several parameters of the working process are not studied well enough to provide the basis for optimal construction design and its qualitative assessment within the design stage. The description of gears operation, the system of end clamping, end, and radial plain bearings is given. The analysis of pressure distribution models is given. The analysis takes into account pressure distribution from linear distribution in the delivery chamber to the pressure drop on one tooth. Distributions from different calculation methods and literature sources are compared as well. The features of bearing loading and the conditions of their operation and lubrication are described. Based on the preliminary calculations, recommendations in the literature, and experimental data, the operation features analysis of the gear fuel pump of the gas turbine engine is carried out. There are defined problems that will provide answers to the main modeling issues in the article: pressure distribution in the intertooth displacement chamber during stationary and transient operating; fluid leakage through variable end clearances and radial clearances; dynamic of the gears and associated parts movement; the influence of external conditions (temperatures, pressures, external vibrations, etc.) on the operation of the pump in general.

Friction and wear resistance of Al2O3 40TiO2 (AMDRY 6250) coating of a pump shaft sleeve bearing

The equipment of wastewater treatment plants is continuously subjected to different kinds of wear, as corrosion, abrasion, cavitation, erosion etc. The most affected components are those of slurry pumps, the slurry producing intense abrasive wear. The service life of pumps (wear rings, sealing, bearings, impellers, and casings) can considerably be extended by proper coating. Before the implementation of a new coating in equipment, its friction and wear behaviour must be determined beside corrosion resistance. This paper presents the results of friction tests carried out on AMSLER machine. The tribological pair was composed by Al2O3 40TiO2 (AMDRY 6250) coating deposited on substrate of a pump shaft sleeve running against a rolling bearing steel disk in dry lubrication conditions. The experimental results are compared against those obtained for uncoated steel.

Design and Dynamic Performance Study on Hydrostatic Lubrication System of High-speed Precision Roller Grinding Head

To meet the need of high-speed steel roll grinding, a hydrostatic lubrication system for high-speed precision roller grinding head is designed and the dynamic performance of the system is simulated and analyzed in this study. The hydrostatic lubrication system was designed according to the lubrication characteristics of the eccentric sleeve and thrust bearing of the high-speed precision roller. Then the mathematical models of the main components of the system were established. And according to the schematic diagram of hydrostatic lubrication system, the dynamic performance of the lubrication system at high speed was simulated and tested. The simulation and experiment results show that the lubrication effect of the eccentric sleeve static chambers and thrust bearings is good, and the designed hydrostatic lubrication system is feasible.

State space model for vibration control with arbitrary controller structures for soft mounted induction motors with sleeve bearings fixed on active motor foot mounts

AbstractIn the paper, a state space model for vibration control with arbitrary controller structures for soft mounted induction motors with sleeve bearings fixed on active motor foot mounts is shown. Besides the mathematical description of the forced vibrations caused by dynamic rotor eccentricity, a procedure is presented to derive the threshold of vibration stability. The challenge of the paper is the use of arbitrary controller structures with different feedback strategies – feedback of the motor feet displacements, velocities or accelerations – in combination with a special vibration system. This specialty is, that the stiffness and damping matrices depend on the rotor angular frequency Ω, which corresponds to the excitation angular frequency, when analyzing the forced vibration, and depend additionally on the natural angular frequency ωstab of the critical mode, when analyzing the threshold of stability. After the mathematical description is shown, a numerical example of a 2‐pole induction motor (power rating 2.4 MW) is presented, in which the threshold of stability is analyzed as well as the forced vibrations due to dynamic rotor eccentricity by investigating the bearing housing vibrations, the foundation vibrations and the actuator forces.