Antifriction Bearings Research Articles

Experimental investigation of the static and dynamic damping behaviour of antifriction bearings

ABSTRACT This paper experimentally investigates the vibration-damping behaviour of four different antifriction bearings. Both static and dynamic analyses have been employed to study the damping behaviour. Experiments are conducted on a custom-made rotor bearing test rig, and the results are analysed with the OROS NV-Gate data collection system at DE (Drive end) and NDE (Non-drive end). Free vibration analysis is used to determine natural frequencies. The half-power bandwidth and logarithmic decrement methods are used to get the damping ratios. Furthermore, force vibration tests are carried out on different bearings with varying operating characteristics to support the static analysis results. The results demonstrate that the damping capacity of tapered roller bearings is superior, followed by cylindrical, spherical and self-aligned bearings. The contact between rolling elements and raceways plays an essential role in the damping capability of such bearings. The result of current research has prospective applications in the design of high-performance rotor bearing systems.

Fault diagnosis of anti-friction bearings based on Bi-dimensional ensemble local mean decomposition and optimized dynamic least square support vector machine

In order to ensure the normal operation of rotating equipment, it is very important to quickly and efficiently diagnose the faults of anti-friction bearings. Hereto, fault diagnosis of anti-friction bearings based on Bi-dimensional ensemble local mean decomposition and optimized dynamic least square support vector machine (LSSVM) is presented in this paper. Bi-dimensional ensemble local mean decomposition, an extension of ensemble local mean decomposition from one-dimensional signal processing to Bi-dimensional signal processing, is used to extract the features of anti-friction bearings. Moreover, an optimized dynamic LSSVM is used to fault diagnosis of anti-friction bearings. The experimental results show that Bi-dimensional ensemble local mean decomposition is superior to Bi-dimensional local mean decomposition, optimized dynamic LSSVM is superior to traditional LSSVM, and the proposed Bi-dimensional ensemble local mean decomposition and optimized dynamic LSSVM method is effective for fault diagnosis of anti-friction bearings.

A Dynamic Model of Outer Race Defective Bearing Considering the Unbalanced Shaft-Bearing System With Experimental Simulation

Abstract In this study, the effects of the evolution of bearing outer race defect size and increase in speed on the vibration characteristics of a shaft-bearing system under unbalanced conditions are simulated and analyzed. A two degrees-of-freedom mathematical model is presented for a ball bearing used in an unbalanced shaft-bearing system. The contact stiffness between the races and the balls is considered as a series of springs is incorporated in the model. Hertzian contact deformation theory is used to obtain the contact stiffness. This model considers the contact deformation between the balls and the races, the additional displacement between the balls and the inner race due to radial clearance and due to defect geometry. The maximum possible radial displacement of the ball into the defect is calculated analytically using the groove radius, ball radius, and defect diameter. The rectangular function is used for modeling the defect. matlab codes are developed for modeling the bearing and for solving the differential equations of motion using the Runge–Kutta method. The vibration responses (peak and root-mean-square (RMS) values) obtained by modeling and by experimentation show similar vibration characteristics. The investigation shows that the values of statistical parameters initially increase with the increase in defect size and then decrease with a further increase in defect size. While peak and RMS increase with the increase in speed, crest factor and kurtosis decrease with the increase in speed. Peak is more sensitive for diagnosing spalls on outer race and its evolution. This study helps as an effective diagnosis of antifriction bearings having spalls on the outer race under unbalanced conditions.

Introduction to IEEE 841-2020 for Severe Duty Squirrel Cage Induction Motors—Up to and Including 370 kW (500 hp): Improving Motor Reliability, Maintainability, and Energy Efficiency

IEEE 841-2020 IEEE standard for petroleum and Chemical Industry—Premium Efficiency Severe Duty, Totally Enclosed (TEFC) Squirrel-Cage Induction Motors—Up to and Including 370 kW 500 hp to be issued in 2020 has been updated and improved from the 2009 version. The standard covers three-phase premium-efficiency severe-duty TEFC squirrel-cage induction motors with antifriction bearings in sizes up to and including 370 kW (500 hp). Important changes and updates have been made to the standard, including the addition of some applications for ASD motors in classified locations. Improvements to the standard are reviewed in detail. Requirements are identified that improve motor reliability and increase motor life.

Boron-based Pd3B26 alloy cluster as a nanoscale antifriction bearing system: tubular core-shell structure, double π/σ aromaticity, and dynamic structural fluxionality.

Boron-based nanoclusters show unique geometric structures, nonclassical chemical bonding, and dynamic structural fluxionality. We report here on the theoretical prediction of a binary Pd3B26 cluster, which is composed of a triangular Pd3 core and a tubular double-ring B26 unit in a coaxial fashion, as identified through global structural searches and electronic structure calculations. Molecular dynamics simulations indicate that in the core-shell alloy cluster, the B26 double-ring unit can rotate freely around its Pd3 core at room temperature and beyond. The intramolecular rotation is virtually barrier free, thus giving rise to an antifriction bearing system (or ball bearing) at the nanoscale. The dimension of the dynamic system is only 0.66 nm. Chemical bonding analysis reveals that Pd3B26 cluster possesses double 14π/14σ aromaticity, following the (4n + 2) Hückel rule. Among 54 pairs of valence electrons in the cluster, the overwhelming majority are spatially isolated from each other and situated on either the B26 tube or the Pd3 core. Only one pair of electrons are primarily responsible for chemical bonding between the tube and the core, which greatly weaken the bonding within the Pd3 core and offers structural flexibility. This is a key mechanism that effectively diminishes the intramolecular rotation barrier and facilitates dynamic structural fluxionality of the system. The current work enriches the field of nanorotors and nanomachines.

Preparation and tribological properties of SiO2/WO3 nanocomposite lubricant

PurposeWO3 particles were prepared by the sol-gel method. Tetraethyl silicate (TEOS) was used to obtain a SiO2-coated WO3 nanoparticle. Quantum chemical parameters of oleic acid, triethanolamine, glycerol and methyl pentane as dispersants were theoretically calculated. Tribological properties of SiO2/WO3 nanocomposite lubricant were carried out on an MRS-10A four-ball friction and wear tester.Design/methodology/approachThe purpose of this study is to investigate the preparation and tribological properties of SiO2/WO3 nanocomposite lubricant.FindingsThe obtained SiO2-coated WO3 nanoparticle (nano-SiO2/WO3) with a particle size of about 70 nm. The calculated adsorption energy of triethanolamine on the surface of the steel ball is 554.6 eV, and triethanolamine is selected as the dispersant. The dispersion effect of SiO2/WO3 nanocomposite lubricant is good, which shows that triethanolamine oleate plays a good dispersion role in the preparation of lubricant, which is consistent with the calculation results of the adsorption capacity of dispersant. As a good auxiliary lubricant, SiO2 can improve the tribological properties and wear resistance of WO3.Originality/valueNanocomposite lubricants have been the focus of research in recent years, which could greatly reduce energy consumption. And the SiO2/WO3 exhibited excellent lubrication performance as a lubricant additive. The lubrication mechanism of SiO2/WO3 nanocomposite lubricant is the synergistic lubrication mechanism of friction film lubrication and antifriction bearing. This study could provide a certain reference for the practical application of nanocomposite lubricants.

Adaptive Band Extraction Based on Low Rank Approximated Nonnegative Tucker Decomposition for Anti-Friction Bearing Faults Diagnosis Using Measured Vibration Data

Condition monitoring and fault diagnosis are topics of growing interest for improving the reliability of modern industrial systems. As critical structural components, anti-friction bearings often operate under harsh conditions and are contributing factors of system failures. Efforts have been cast on bearing diagnostics under the sensor fusion and machine learning framework, whilst challenges remain open on the identification of incipient faults. In this paper, exploiting multi-way representations and decompositions of measured vibration data, a novel band separation method based on the factorization of spectrogram tensors using the low rank approximated nonnegative Tucker decomposition (LRANTD) is proposed and applied to identify detailed fault signatures from the spectral, temporal, and spatial dimensions, flexible for extracting multi-sensor features and multi-dimensional correlations. With the proposed method, informative frequency bands of the latent vibrational components can be automatically extracted, in accordance with the inherent temporal patterns that can be conveniently fed for spectral analysis and fault discrimination. Furthermore, an improved cross-spectrum can be calculated from multi-channel vibrations via LRANTD with enhanced fault features. Based on the real-world vibration data of the accelerated bearing life tests, detailed experimental studies and thorough comparisons to the conventional benchmarks have verified the effectiveness of the reported diagnostic methodology. The proposed method significantly improves the presence of the bearing frequency peaks distinctly over the background noises in the spectrum and hence improves the bearing defect detection process.

Fault diagnosis of antifriction bearing in internal combustion engine gearbox using data mining techniques

Fault diagnosis of antifriction bearing in internal combustion engine gearbox using data mining techniques

Effects of Textured Surface Combined with Sn-Ag-Cu Coating on Tribological Properties and Friction-Induced Noise of Ti-6Al-4V Alloy

To improve the tribological properties and suppress the friction-induced noise of Ti-6Al-4V alloys (TC4), TC4 with smooth surfaces (TSs), groove antifriction surfaces (GAs), Sn-Ag-Cu coating surfaces (SCs), and composite self-lubricating surfaces (CSs) with grooves and Sn-Ag-Cu coating were prepared. Experimental studies on the tribological properties and friction-induced noise were carried out. The results showed that TSs produced high-frequency scream for adhesive wear. GSs suppress the scream noise but induce low-frequency chattering. CSs with uniform profiles and smaller wrinkles showed tribochemical wear characteristics, which produced the various intermetallic compounds and oxides, improving the surface profiles and suppressing the microdefects. The synergistic effects of grooves and Sn-Ag-Cu coating on CSs reduce the high contact stresses of groove edges and suppressed the adhesive wear and friction-induced noise. The friction and noise reduction mechanisms of CSs are beneficial to obtain surfaces with the best antifriction performance and bearing capacity by improving the profiles.

Investigations of Antifriction bearing defects using Vibration Signatures

Antifriction bearing failure is a major factor in the failure of rotating machinery. As a fatal defect is detected, it is common to shut down the machinery as soon as possible to avoid catastrophic damages. Performing such action typically results in substantial time and economic losses. Therefore it is important to monitor the conditions of antifriction bearings and to know the details of the severity of defects before they cause serious catastrophic consequences. The vibration monitoring technique is the most suitable method to analyze various defects in bearing. This technique can provide early information about progressing malfunctions. Time-domain analysis and frequency domain analysis have been employed to identify different defects in bearing running at three different speeds. Defect-free and defective bearing are used for testing. Time-domain and frequency-domain signals acquired for both good and defective bearings Time waveform indicated the severity of vibration in defective bearings. The frequency spectrum is used to identify the amplitudes corresponding to fault frequencies and enables to predict of the defect presence. The roller bearing is considered for analysis. Three types of defects namely outer race, inner race, and rolling element defect are considered. Experimental data of both defect-free and defective bearings are processed to show the effectiveness of the fault diagnosis using this method. In fault monitoring and diagnostics of bearings, real-time processing and fast on line fault indication are becoming increasingly important. Towards this goal, attention has focused on a search for the use of effective signal processing and signatures extracting methods to realize immediate fault detection.

Device for integrated diagnostics of mining machines triboelements

This article presents the results of multiple-conditions wear-resistance tests for the antifriction bearings that are used in a milling tool. The test was performed on a one-fifth milling tool model. The tests were divided into three stages. The first testing stage included tests of a model with a new undamaged bearing. The second stage included tests of a model with a bearing that is worn out by approximately 50%. The third stage included tests of a model with a completely worn out antifriction bearing. Along with vibroacoustic tests, we measured the temperatures of the tested triboelement. In this article, we provide amplitude-frequency values of vibroacoustic signals recorded during the tests of a model with an undamaged antifriction bearing, a bearing with 50% worn-out extent, and 100% worn-out bearing. Appropriate resistance levels of complex machine elements cannot be achieved without systems of triboelements condition control. We suggest attaching temperature and vibroacoustic sensors to the critical elements of a peat winning machine that provide data for integral analysis of triboelemets condition and prevent failures when damage is recorded. Integral analysis of the technical condition of the main triboelements will allow performing the highly precise prognosis of the remaining life of a peat-winning machine, thus preventing failures in peat mining seasons.

A numerical model for fault diagnosis in deep groove ball bearing using dimension theory

Antifriction Bearing is the prime moving element in condition monitoring high speed rotating machines. Bearing failure due to progression in surface defects leads to malfunction in rotating machines—even minute malfunction results in the disintegration of a system, cost, and product quality. In view of this paper presents Dimension Theory by Matrix Technique (DTMT) to analyze vibration response theoretically. The vibration responses of surface faulty bearings are compared with the mathematical model developed by DTMT to emphasize its validity in fault identification. Good correlation is observed between mathematical model and experimental results..

Spectrum analysis of rolling element bearing faults

The health status of these bearings efficiently and effectively can be monitor using the spectrum analysis. The rolling element bearings are of two types rolling and sliding rolling element bearings, and these Sliding rolling bearings are of two types, linear and journal rolling bearings. The combination of both roller and ball can be referred to as rolling element bearings and can be widely used in many applications. The usage can be wide a range because of the permit rotary motion of shafts, starting from aircraft gas turbines, power transmissions, electric motors, bicycles, roller skates and many more. As the rolling element bearings have many advantages, compared with other types of bearings. As they are commonly referred to as antifriction bearings because the amount of lubrication required is less. In this paper, a new dimension is added for the spectrum analysis of rolling element bearing faults detection, analysis and diagnosis. Her the rolling element bearing faults are studied in comparison with three major factors like the time domain, frequency domain and spectrum plot obtained for the rolling element faults. The spectrum obtained from the normal and inner, outer race faults are consider mapping the spectrum analysis in more effective way.

Evolution of ultrafine precipitates and its influence on wear mechanism in cryoprocessed high nitrogen martensitic steel

ABSTRACTDevelopment of the space engines with liquid propellants necessitates the use of bearings of high quality. During recent years, a new family of high strength corrosion resistant steels, with partial replacement of carbon by nitrogen, known as high nitrogen steels were developed having higher impact strength and fracture toughness coupled with high hardness for antifriction bearing of cryopumps in rocket. In this research work, wear characteristics of cryogenically treated high nitrogen martensitic stainless steels were investigated by Pin-on-disc wear testing machine. After conventional hardening treatment, specimens were subjected to cryogenic treatment at −196°C with cryosoaking period varying from 8 to 32 h in the interval of 8 h followed by soft tempering. These specimens were analysed for hardness, wear resistance, subsurface and worn surface features by SEM. It is established that there is a profound influence of nucleation and growth of precipitates on the wear behaviour and the underlying wear mechanisms.

Formulation of Mathematical Model for the Vibration Response of Machine Components Placed on a Shaft Supported By Six Journal Bearings

The present state of the art of vibration based condition monitoring for the machine components placed on a shaft supported by more than three bearings seems to be inadequate. To propose an alternative approach over the present state of the art, an attempt has already been made considering a shaft supported by six antifriction bearings. However, a further attempt is made through this work by adopting the same approach considering six journal bearings. To validate this new approach, an experimental set-up is designed, fabricated and experimentation is executed. A further attempt is made to formulate the mathematical models to predict the vibration response.

Optimization of Cryogenic Process for Enhancing the Wear Resistance of Novel HNMS Steel for Cryogenic Bearings of Launch Vehicle

Bearings are highly engineered components that have to tolerate vibratory stresses, bending moments, and high rotational speeds in cryogenic applications. AISI 440C is most widely used for antifriction bearings due to its good strength and high hardness but is prone to carbide banding and failure during service. High-nitrogen martensitic stainless steel (HNMS) was recently developed by partially substituting carbon with nitrogen. This article explores the possible improvement in wear properties by cryotreating HNMS steel. The hardening temperature was varied from 1050 to 1100 °C, cryosoaking period from 0 to 12 h at −196 °C, and tempering temperature from 100 to 300 °C for 1 h. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis revealed the presence of carbides and carbonitrides. The phase fraction and size of the precipitates was found to be influenced by the cryosoaking period. The carbide density variation with the cryosoaking period followed a sigmoidal curve. Eight hours of cryogenic treatment at −196 °C was observed to be the optimal cryosoaking period for HNMS steel. Maximum hardness (671 HV) and minimum wear rate (0.00714 mm3/m) and adhesive wear were observed for the optimum heat treatment condition. Compared to conventional hardening-tempering (HT) treatment, the optimized hardening-cryogenic-tempering (HCT) treatment cycle resulted in a 38% increase in hardness and a 31% decrease in the wear rate. The improved properties can be attributed to the presence of fine and uniform distribution of precipitates in the matrix and transformation of retained austenite to martensite.

Studies on Wear Behaviour and DBTT in Sub-zero Regimes of Cryo-Treated High Nitrogen Martensitic Stainless Steel (HNMS)

The development of space engines with liquid propellants require use of highly engineered bearings. High nitrogen martensitic stainless steel (HNMS) is the newly developed steel and is the potential candidate for anti-friction bearings in cryogenic engines in launch vehicles. The present paper aimed to assess the effect of cryogenic treatment on HNMS steel at sub-zero temperature regimes. HNMS steel specimens were treated using optimised heat treatment cycle comprising of hardening at 1075 °C, cryogenic treatment at − 196 °C for 8 h followed by soft tempering at 100 °C for 1 h. The specimens were tested for hardness, wear loss (test load 20–80 N), surface roughness, and impact toughness from room temperature (RT) to the cryogenic temperatures. Worn surfaces, subsurface features, and fractured surfaces were analysed using FE-SEM. It was established that the HNMS steel showed reduced wear rate by 28% and 60% for 20 N and 80 N wear test load, respectively, at − 196 °C as compared to the RT. Severe delaminated wear mechanism was observed at RT as compared to mild adhesive wear at − 196 °C. Impact testing revealed that the DBTT for HNMS steel lied between − 30 and − 60 °C .

Creating and Applying Antifriction Bearing Wood–Metal Materials

Methods of improvement of the tribotechnical characteristics of composite materials, wood–metal, obtained by the introduction of optimization phases in a wood base are given. The proposed and investigated schemes and methods of forming antimic innovative wood–metal bearings with the use of modified timber and metal particles, made of various antifriction materials, are shown. Ex-plateruena under the action of high temperatures, i.e., heat storage fillers made in the form of capsules filled with a fusible alloy, are also proposed for wood–metal liners. The tribological capabilities of the new wrapped wood–metal liners consisting of successive layers of thermally conductive mesh or tape and wood veneer are studied.

Fault Detection of Anti-friction Bearing using Ensemble Machine Learning Methods

Anti-Friction Bearing (AFB) is a very important machine component and its unscheduled failure leads to cause of malfunction in wide range of rotating machinery which results in unexpected downtime and economic loss. In this paper, ensemble machine learning techniques are demonstrated for the detection of different AFB faults. Initially, statistical features were extracted from temporal vibration signals and are collected using experimental test rig for different input parameters like load, speed and bearing conditions. These features are ranked using two techniques, namely Decision Tree (DT) and Randomized Lasso (R Lasso), which are further used to form training and testing input feature sets to machine learning techniques. It uses three ensemble machine learning techniques for AFB fault classification namely Random Forest (RF), Gradient Boosting Classifier (GBC) and Extra Tree Classifier (ETC). The impact of number of ranked features and estimators have been studied for ensemble techniques. The result showed that the classification efficiency is significantly influenced by the number of features but the effect of number of estimators is minor. The demonstrated ensemble techniques give more accuracy in classification as compared to tuned SVM with same experimental input data. The highest AFB fault classification accuracy 98% is obtained with ETC and DT feature ranking.

Research of transformation process of barrier layers in antifriction bearing with solid lubricating filler at autoclave simulated operation

AbstractFor the time being, solutions to increase coupling durability are being searched for in a number of aspects: process design; physical and chemical, aimed at creating innovative and improving existing materials; physicometallurgical, aimed to find scientifically justified solutions to composition, structure, and property issues related to materials intended for production of components of friction assembly and methods to impact their near‐surface layers. An in‐depth study of kinetics of structural, phase and diffuse transformations is required in order to solve these problems. Researching the processes that occur when graphite‐based solid lubricants are in use, we will also examine strength and deformation properties of friction pair surface microvolumes. An objective of this paper is to study transformation processes of near‐surface layers in antifriction bearing while using solid‐antifriction lubricating fillers.