Ring Of Bearing Research Articles

Effects of an annular groove formed on contact surface on fretting wear between inner ring and backing ring of railway axle journal bearings

Fretting wear is surface damage caused by repeated slight relative slips between two contact surfaces. In railway applications, fretting wear can occur between the inner ring and the backing ring of an axle journal tapered roller bearing. The authors found that the fretting wear area of the backing ring is approximately coincident with the area where the amplitude of the contact pressure is larger. Thus the fretting wear may be reduced by designing so that the backing ring side face, where the contact pressure increases, does not contact the inboard inner ring side face. The aim of our study is to obtain knowledge to suppress the fretting wear of the axle bearings and to prevent the fretting wear particles from entering the inside of the bearing, without increasing the number of bearing components. Therefore, we have conducted a rotation test of a full-scale railway axle bearing with a backing ring formed an annular groove on its side face to investigate the fretting wear preventive effect. Results indicate that the annular groove on the backing ring side face was found to be effective in collecting fretting wear particles in the groove, but the fretting wear generated in the backing ring with the annular groove was more noticeable than that in the backing ring without the annular groove. We conclude that the formation of an annular groove on the contact surface between the inner ring and the backing ring is ineffective in preventing the fretting wear of axle journal bearings.

Analyzing Vibration Mechanism of Angular Contact Ball Bearing with Compound Faults on Inner and Outer Rings

This paper investigates a method to dynamically model compound faults on the inner and outer rings of an angular contact ball bearing as well as their effects on its dynamic behavior. Gupta’s dynamic modeling method is used to consider changes in the deformation and direction of the contact load when the ball passes through the damaged area and to develop a dynamic model of compound faults in the angular contact ball bearing. The step‐changing fourth‐order Runge–Kutta method is used to solve the dynamic compound fault model. The time‐domain signal of vibration responses in the case of a single fault in the inner and outer rings exhibited a certain periodicity, and the frequency of faults in the envelope spectrum was clear. By comparison, the periodicity of compound faults was not clear. The signals of compound faults were decomposed by the dual‐tree complex wavelet transform to identify their characteristic frequency. Errors occurred between the characteristic frequency of the theoretical fault and its simulated value. They increased with the rotational speed and decreased with an increase in axial load, whereas the influence of radial load on them was minor. For compound faults on the inner and outer rings of an angular contact ball bearing, this study provides a modeling method that can describe changes in the deformation and direction of the contact load when the ball passes through the damaged area of the inner and outer rings. The work here can provide an important foundation for fault identification in angular contact ball bearings.

White Etching Bands Formation Mechanisms Due to Rolling Contact Fatigue

White etching bands (WEBs), known as subsurface micro-structural changes in bearing steels due to cyclic stresses in rolling contacts, have been studied for decades and a number of theoretical models have been proposed to explain their formation mechanisms and predict their initiation. While many studies focus only on one subtype of WEBs, e.g. low angle bands (LAB) or high angle bands (HAB), the most recent semi-empirical model has shown to be able to predict the formation of both LAB and HAB based on observed growth patterns of ferrite grains. Following from the modelling study, this paper presents a detailed mechanistic study, showing the evolution of ferrite grains (equiaxed and elongated grains) and carbide structures in WEBs formed in inner rings of angular contact ball bearings at their different life stages through SEM, EBSD and nano-indentation analysis. The results strongly suggest both LAB and HAB initiate as equiaxed ferrite grains due to recrystallization arising from energy build-up in the initial microstructure that later develops to elongated ferrite grains due to a grain rotation/coalescence recovery mechanism induced from plastic deformation. The formation of carbide structures in LAB is associated with the transformation of equiaxed to elongated grains, where carbides nucleate at the edges of the elongated grains rather than at the equiaxed grain band edges as being previously suggested in literature. The newly proposed formation mechanism links LAB and HAB based on experimental findings from detailed inspection of gradual microstructural alteration sequence of LAB and HAB in rolling contact fatigue (RCF) tested bearings.

Load analysis and deformation research of the flexible bearing based on a three-force ring superposition method

The flexible bearing is a key component of harmonic reducer enabling the flexspline to generate a controllable elastic deformation. Its performance and life will significantly affect the normal operation of harmonic reducer. In order to improve the life and the working performance of the flexible bearing, the calculation of its load distribution is necessary. Based on the theory of thin-walled ring, the relationship between radial deformation and load of three-force ring was derived. Then a superposition model of three-force ring was developed to calculate rapidly the load distribution of flexible bearings with elliptical cams in harmonic reducers. The validity of the proposed model was proved by comparing with a static analysis model. In this paper, the influences of ball number and external load on the load distribution, radial deformation and bending normal stress of outer ring were investigated by three-force ring superposition method. Based on the deformation of three-force ring, the deformation characteristics and bending normal stress distribution of outer ring of the flexible bearing were analyzed, and several regular results were found.

Patterns of Acoustic Wave Propagation in the Contact Layer of Press Joints

The insufficient strength of the fixed releasable press joints in the inner rings of the bearings with the pins of the wheelset axles leads failures of axle boxes. During the operation it is possible to change the bearing strength of the bearing rings, which may result in grinding of an axle pin part, fretting corrosion and ring rotation. In order to control the integrity of the ring on the axis pin, the most promising is implementing the acoustic methods. Such methods are based on the correlation between the reflection coefficient of ultrasonic waves at the boundary with the rolling surface of the ring and its stress-strain state (and, as a consequence, the integrity). The reflected ultrasonic waves contain information on the parameters of the contact liquid layer and the acoustic properties of the ring material. The goal of the research is to study the effect of the contact fluid layer between the transducer and the tested samples from different materials on the parameters of the recorded signal during ultrasonic testing. Throughout the research, an original combined transducer was manufactured. Testing of samples from various materials by ultrasonic echo method testing was carried out. The amplitude-frequency characteristics of the signals reflected from the studied samples are obtained. The reflection coefficients of longitudinal waves reflected from the boundary “transducer – test sample” at frequencies of 2.5 and 5 MHz were experimentally determined. The correlation between the reflection coefficient and the grinding degree of the transducer and the test sample is determined.

Integration of process monitoring and machine condition diagnostics to improve quality prediction in grinding

Bearing ring grinding incorporates sensors to control the grinding cycle in real time. Prediction of output quality is difficult due to the complex combination of process settings and machine characteristics. Causal relationship of machine performance with varying operating conditions was studied with reference to the produced quality by adding condition monitoring setup to the machine. Data driven diagnostics of machine condition through integration of condition and process monitoring sensor data at the completion of the grinding cycle improves quality cognisance. This can be used to tune control parameters to achieve more predictable quality in successive cycles.

Grey Relation Evaluation and Truth Value Fusion of Rolling Bearing Multisource Residual Stress

Bearing ring residual stress test data obtained by µ-360 s residual stress analyzer have the characteristics of unknown probability distribution and limited samples. For this problem, this study introduces the uncertainty and proposes a grey relation method to estimate the true value of the bearing ring residual stress. Based on poor information theory (incomplete and insufficient information for the characteristic presented in the subject investigated) and by fusing the membership function method, maximum membership method, rolling mean method, and bootstrap method, the true value sequence of the residual stress is obtained. On this basis, true value fusion is implemented again using the grey bootstrap method, and the estimated true value of the residual stress for the bearing ring was obtained. The results show that the residual stresses of bearing rings are fused by multiple methods, and the overall estimated true value of the residual stress of the bearing ring is −578 MPa. Owing to different processing techniques, the true value of the residual stress varies in different parts of the ring as follows: −918 MPa on the large end surface of the ring, −673 MPa on the small end face of the ring, −228 MPa at the vertical test point on the outer surface of the ring, and −231 MPa at the parallel test point on the outer surface of the ring. The error between the estimated true value obtained using the grey relation method and that obtained through the fusion of multiple methods is generally 10% or less, thereby confirming the effectiveness of the grey relation method.

Mathematical model of allowance removal at nonabrasive processing of bearing details

To increase the durability of the bearing, it is necessary to achieve a profile shape of the groove of the bearing close to that obtained during running-in. This effect allows you to achieve a method of non-abrasive tuning of the raceways of the rings of roller bearings. To study the effectiveness of this method, it is necessary at the initial stage to build a mathematical model of metal removal from the treated surface. To derive the mathematical model, we used the energy theory of friction, the theory of elasticity, and the physical theory of similarity. After the conclusion of the model, you can see which factors have the greatest impact on the efficiency of the process of non-abrasive tuning of the raceways of the roller bearing rings.

Features of determining the efficiency of the cam wave generator of the wave gear

The object of study is a wave gear with a cam wave generator. One of the requirements for wave gears is to increase their efficiency. The article considers a refined method for determining the efficiency of a flexible bearing, taking into account the deformation of the flexible wheel, hard wheel, outer ring of the flexible bearing, cam shaft, shaft of the flexible wheel, as well as contact deformations of teeth, FB balls, roller paths of the outer and inner rings of the flexible bearing. According to the proposed method, the influence of the resistance moment, gear wheel displacement coefficients and radial deformation of a flexible wheel on the efficiency of a flexible bearing is investigated. The obtained dependencies expand knowledge about the influence of various factors of wave transmission of the efficiency of flexible bearings.

Evolution of microstructure and mechanical properties of the high-speed train bearing under different service periods

The microstructure and mechanical properties of high-speed train bearing are significantly influenced by the harsh service environment during the long-term service process, which is crucial for the safety and service life of bearing. In this paper, the outer ring of high-speed train bearing is taken as the research object. The microstructure of the outer ring under different service periods was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) combined with electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). The mechanical properties were measured by the MTS testing machine and microhardness tester. The evolution of microstructure and mechanical properties of the high-speed train bearing outer rings under different service periods was investigated by comparative analysis. The results show that, with the increase of the service period, the bainite in bearing outer ring become coarser, the number of acicular carbides increases, and size of microcracks increases. Moreover, the dislocation density and microhardness near the inner-surface of the outer ring increases slightly. However, both yield strength and ultimate strength decrease with the increase of the service period.

The Design and Analysis of Roller Cone Bit Bearing Ring

Increasing the sealing performance of bearing rings of roller-cone bits plays an important role in reducing the bearing seal failure and improving the service life of drill bits. This paper conducts (1) the structure design of the sealing rings. (2) a simulation on the new designed structure of roller cone bit. The contact pressure together with the equivalent stress of the new tooth bars was analysed by building up the finite element model of the bionic non-smooth surface structure, beyond that the comparisons between the new structure and O type sealing ring were carried out. The results indicate that the ribbed sealing structure is capable of improving the wear resistance, postponing the wear abrasion and ageing, and increasing the service life of rubber ring.

Influence of Plastic Deformation on Microstructural Evolution of 100Cr6 Bearing Ring in Hot Ring Rolling.

The hot ring rolling technology as the crucial procedure for the manufacture of bearing rings plays an important role in determining the final microstructure of bearing rings. In this work, the influence of the hot ring rolling process on the microstructural evolution of 100Cr6 bearing rings was investigated using a three-dimensional (3D) numerical model and microstructural characterization. It was found that the significant microstructural refinement occurs at the different regions of the rings. However, owing to the non-uniform plastic deformation of hot rolling, the refinement rate of grain size and decrease of pearlite lamellar spacing (PLS) also showed uniformity at different regions of the rings. Furthermore, the degree of grain refinement had been limited with the increase of rolling reduction. Due to the refined grain size and decreased PLS, the Vickers hardness increased with the increase of rolling reduction. Moreover, the Vickers hardness from the outer surface to the inner surface of the ring is asymmetrical u-shaped, which had the law of lower hardness in the center area and higher hardness on the surface.

Grease film thickness measurement in rolling bearing contacts

Rolling bearings are the second most used machine components. They work in what it is called elastohydrodynamic lubrication regime. The geometry of rolling element bearings makes the direct measurement of the lubricant film thickness a challenging task. Optical interferometry is widely used in laboratory conditions for studying elastohydrodynamic lubrication however it cannot be used directly in rolling element bearings thus the only suitable methods are electrical techniques. Of these, film thickness measurement based on electrical capacitance of the contacts has been used in the past by a number of authors. One of the limitations of the capacitance method, when used in rolling bearings, is that it cannot distinguish between the contacts of every rolling element and raceway on one hand and on the other between the inner and outer ring contacts. In the present study the authors used an original test rig which can measure the film thickness for only one ball and separately for the inner and outer rings of a radial ball bearing. This paper thus shows for the first-time results of the lubricant film thickness, at the inner and outer raceways, in grease lubricated rolling bearings.

Elimination of Cracks in GCr15 Bearing Rings After Heat Treatment

The main chemical components of GCr15 bearing steel are Fe, Cr, C, Mn, etc., which are mainly used to produce bearing rings, rolling elements and other rolling bearing manufacturing industries. After more than one hundred years of development, GCr15 material is used for manufacturing bearing components, and it is called “heart of industry” because GCr15 material is one of the best quality steels [1]. After heat treatment, GCr15 material steel has the “most extensive” practicality for various working conditions of the bearing, such as high load capacity, good fatigue resistance, strong wear resistance, and high hardness, better temperature adaptability and so on [2]. This paper first discusses the heat treatment process of GCr15 material, and then analyzes and studies the cracking phenomenon of a certain batch of 1m diameter GCr15 material bearing ring blanks after heat treatment, and focuses on the fracture morphology, chemical composition, microstructure and other phenomena. The analysis found the cause of the crack and improved the original heat treatment process, that is, before quenching, isothermal spheroidizing annealing is used and the spheroidizing annealing temperature is strictly controlled, bainite austempering is used to replace martensite quench tempering after quenching, and finally, the problem is solved through experimental verification.

Method of gearbox state estimation of the metro tunnel escalator drive

A method for detecting excitations leading to the damage of the gears and bearings working surfaces has been developed by means of experimental study of the dynamic characteristics of the metro tunnel escalator drive gearbox in normal and bad performance. The technique is based on the acquisition and analysis of low and high resolution spectra. The technique is tested during the analysis of vibration spectra of a standard three-stage, four-shaft tunnel escalator drive gearbox. The vibration analysis was performed using the kinematic excitation frequencies generated by the gears and rolling bearings in the zones of resonance vibrations of the gearbox elements. According to the results of the analysis, the presence of variable stiffness of the teeth in one of the gears and damage of the inner ring of the ball bearing of the intermediate shaft cover is established.

The Effect of Surface Morphology of Tapered Rolling Bearings in High-Speed Train on Grease Lubrication

With the extensive coverage of the rail transit system, ensuring the safe operation of rail vehicles is an important prerequisite. Insufficient lubrication will cause friction and wear of axle box bearings, which is directly related to ensured safety of high-speed trains. A non-Newtonian elastohydrodynamic lubrication(EHL) between tapered rolling elements and inner ring of axle box bearing in high-speed trains was established by numeric simulation. The input parameters of working conditions, including velocity, acceleration and plastic viscosity, were changed, considering the actual application and their influence trends on film-forming characteristics were analyzed. As a result, a phase of acceleration of starting or a process of braking at a low speed tends to occur mixed lubrication. Therefore, a method of optimizing surface morphology of rolling elements was adopted to improve lubrication. Based on comparison experiments, it was recommended that RMS roughness was greater than 0.03 μm and less than 0.1 μm and kurtosis was three and skewness was negative in a range of −1 to −0.5 and texture direction was parallel to rotation direction. The optimized surface promotes the transition from mixed-lubrication to full film lubrication, which alleviated the problem of surface damage due to insufficient lubrication and prolongated the service life.

Bearing fault identification based on ASMOTE-CFR

Aiming at the problem of data unbalance caused by the lack of bearing failure test data, the paper proposes a collaborative filtering recommendation (CFR) method for adaptive Smote (ASMOTE) resampling and matrix decomposition of minority samples (ASMOTE-CFR). The method first adopts adaptive Smote method to synthesize different number of new sample equalization test data sets according to the data distribution. and then a variety of typical feature values such as time domain, frequency domain, time frequency domain, etc. are extracted to obtain the bearing feature matrix, and then a scoring matrix that accurately describes the bearing state is designed and based on the matrix Based on the decomposed collaborative filtering algorithm, a set of collaborative filtering recommendation system for bearing state recognition is proposed. Using this method, different forms of fault data on the outer ring of the rolling bearing were identified and verified. The accuracy of identification reached more than 98 %. Compared with the recognition accuracy of the collaborative filtering recommendation algorithm, this method improved 8 %.

Shaft Integrated Electromagnetic Energy Harvester with Gravitational Torque

This paper presents the development of an electromagnetic energy harvester for electrical supply of a sensor unit integrated on the rotating inner ring of a rolling bearing. This energy harvester is of special interest for condition monitoring tasks on rotating shafts. A sensory monitor on the inner ring can detect wear conditions at an early stage. The harvester works without mechanical and energetic contact to surrounding components by utilizing the rotational energy of the shaft. The functionality of the Energy Harvester is enabled by the inertia principle, which is caused by an asymmetrical mass distribution. We provide simulations to validate the designs. This work includes simulation studies on the electrical power output of the harvester. Therefore, the necessary simulation of the magnetic problems is realized in a substitute simulation environment. The harvester design enables existing machines to be equipped with the harvester to provide an energy supply on rotating shafts. This clamp connection enables shaft mounting independent of location without mechanical work on the shaft. With an electrical power of up to 163.6 m W, at 3600 rpm, the harvester is used as an energy supply, which enables sensor-based monitoring of slow wear processes.

Technological support of the form-profile of the profile of the rings of the rolling bearings

The methods of forming the working surfaces of the rings of rolling bearings are considered. The influence of the shape of the profile of the rings on the performance characteristics of bearings is shown. The schemes of finishing the rings by superfinishing with profile bars and polishing with an inertial compacted abrasive particles are given. A new technology for improving the quality of the working surfaces of the rings is proposed and the results of experimental studies of the efficiency of ring processing are presented.

Preparation and Properties of the Composite Enhancement Layer of Bearing Ring

In this paper, the NU308 bearing rings were subjected to strengthen grinding treatment (SGT) at ambient temperature. And the running reliabilities of specimens that subjected to SGT and conventional treatment (CT) were respectively investigated by testing dynamic properties including the running temperature, vibrations, and surface burning. Moreover, the residual stress, microtopography, and microstructures on the cross-section were respectively tested with residual stress analyzer and field-emission scanning electron microscopy. The results showed that the running reliabilities of the specimen after SGT had been significantly improved with the reduction of running temperature, vibration, and surface burning. Further study showed that the specimen’s surface was filled with disordered micropores after SGT compared to the regular strip texture on the CT specimen’s surface, and the maximum residual compressive stress induced by SGT was about −900 MPa. Moreover, the thickness of the residual compressive stress layer was over 180 µm, while the thickness of severe plastic deformation layer was about 50 µm.