Raceway Of Bearing Research Articles

3-D Vision Based Magnetic Particle Indication Measuring for Identification and Evaluation of Cracks in Hub Bearing Raceway

3-D Vision Based Magnetic Particle Indication Measuring for Identification and Evaluation of Cracks in Hub Bearing Raceway

WLI, XPS and SEM/FIB/EDS Surface Characterization of an Electrically Fluted Bearing Raceway

Electrical bearing currents may disturb the performance of the bearings via electro-corrosion if they surpass a limit of ca. 0.1 to 0.3 A/mm2. A continuous current flow, or, after a longer time span, an alternating current or a repeating impulse-like current, damages the raceway surface, leading in many cases to a fluting pattern on the raceway. Increased bearing vibration, audible noise, and decreased bearing lubrication as a result may demand a replacement of the bearings. Here, an electrically corroded axial ball bearing (type 51208) with fluting patterns is investigated. The bearing was lubricated with grease lubrication and was exposed to 4 A DC current flow. It is shown that the electric current flow causes higher concentrations of iron oxides and iron carbides on the bearing raceway surface together with increased surface roughness, leading to a mixed lubrication also at elevated bearing speeds up to 1500 rpm. The “electrically insulating” iron oxide layer and the “mechanically hard” iron carbide layer on the bearing steel are analysed by WLI, XPS, SEM, and EDS. White Light Interferometry (WLI) is used to provide an accurate measurement of the surface topography and roughness. X-ray Photoelectron Spectroscopy (XPS) measurements are conducted to analyze the chemical surface composition and oxidation states. Scanning Electron Microscopy (SEM) is applied for high-resolution imaging of the surface morphology, while the Focused Ion Beam (FIB) is used to cut a trench into the bearing surface to inspect the surface layers. With the Energy Dispersive X-ray spectrometry (EDS), the presence of composing elements is identified, determining their relative concentrations. The electrically-caused iron oxide and iron carbide may develop periodically along the raceway due to the perpendicular vibrations of the rolling ball on the raceway, leading gradually to the fluting pattern. Still, a simulation of this vibration-induced fluting-generation process from the start with the first surface craters—of the molten local contact spots—to the final fluting pattern is missing.

Formation Mechanisms and Crack Propagation Behaviors of White Etching Layers and Brown Etching Layers on Raceways of Failure Bearings

White etching layers (WELs) and brown etching layers (BELs), formed on the upper layer of bearing raceways generally lead to surface crack initiation and propagation and significantly affect the stable operation of precision bearings. In this study, the microstructure features of WELs and BELs from two failure bearings have been characterized and analyzed. The BEL mainly consists of quenched martensite with higher hardness values. The bainite simultaneously exists at the boundary of the BEL/matrix. Owing to the relative roll and slip, temperature increases and rapid decreases are the main formation mechanisms of the BEL in this study (thermal-induced effect). The WEL can be only found on one sample, and elongated and coarse grains are found in this region. It can be speculated that the WEL may originate from the surface region temperature increasing again and then slowly decreasing. Cracks can initiate at the boundaries of the WEL/BEL/matrix. The crack propagation behaviors are significantly affected by the properties of the WEL and BEL microstructure. It is difficult for the cracks to propagate from a softer WEL into a harder BEL. Thus, the depth of cracks in the WEL is shallower. However, because of the brittle nature of quenched martensite in the BEL, cracks can easily propagate downward under contact stress. Thus, the depth of cracks can exceed 100 μm easily. The formation mechanisms of the WEL/BEL and crack propagation behaviors have been further proved and discussed in this study.

Fatigue failure of high precision spindle bearing under extreme service conditions

Four sets of high precision spindle bearings (HPSB) had been in extreme service for 6040 h and 85,000 r/min. The service temperature, wear fatigue form, hardness, residual stress, retained austenite, metamorphic layer and element content of the bearing raceway were analyzed. The surface layer and inner layer of bearing raceway were analyzed by Electron Backscatter Diffraction (EBSD), Focused Ion Beam (FIB) and Transmission Electron Microscopy (TEM). The results show that the service temperature range of the four sets of bearings is from 17.5℃ to 74.7℃. With the increase of rotating speed, the bearing temperature can reach 65℃ at 85,000 r/min. The four sets of bearings have different degrees of wear, including fatigue shedding (FS), wear (W), corrosion (C), peristalsis (P), burn (B) and defect (D). In the extreme speed service, taking the bearing No.2 with the highest temperature as the research object, the maximum and minimum hardness differences of outer ring raceway, inner ring raceway and ball are 423.1 HV, 368.7 HV and 405 HV, respectively. The tangential residual stresses of the outer and inner ring raceways are found to be tensile stresses, which are 31.3 MPa and 110.8 MPa, respectively. The retained austenite in the outer and inner ring raceways of bearings are found to increase abnormally, reaching 36.7 % and 34.7 %, respectively. In addition to the highest Ion (Fe) element, the outer and inner ring raceways of bearings also contain higher Praseodymium (Pr) elements, reaching 35.5 % and 14.5 %, respectively. The maximum thickness of the “white layer” of the outer and inner ring raceways of the bearing is 15 μm and 17 μm, respectively. The surface layer of bearing outer and inner ring raceways contain nanocrystals of 200 nm and 100 nm, respectively. Certain nanocrystalline layer will prolong the service life of bearings. Nanocrystals mainly contain Phosphorus (P) and Copper (Cu) elements. The research findings of this study can provide theoretical and data support for enterprises and scholars in the engineering field.

Investigation on Microstructure and Fretting Wear Properties of GCr15 Bearing Steel Modified by Fine Particle Bombardment

Fretting wear occurring on the roller and raceway of rolling bearings is prone to reduce the reliability of bearings. In this study, fine particle bombardment (FPB) under different air pressures (0.3 and 0.6 MPa) was performed on GCr15 bearing steel, and the microstructure and fretting wear properties of GCr15 bearing steel modified by FPB were systematically investigated. The results show that the surface structure of the samples underwent severe plastic deformation, which led to surface grain refinement and increased in dislocation density. Also, the martensite bundle size decreased, and the densities of low-angle grain boundaries (LAGBs) and high-angle grain boundaries (HAGBs) increased. Moreover, the FPB improved the microhardness and thickness of the deformed layer. The enhancement was positively correlated with the air pressure of FPB. Compared with the untreated sample, the wear volume of the FPB samples increased by 10.1% (0.3 MPa) and 19.0% (0.6 MPa), respectively. Thus, the fretting wear resistance was significantly improved. The main wear mechanism changed from severe adhesive wear, abrasive wear, and fatigue wear to slight adhesive wear owing to the application of FPB.

The Effects of Process Parameters on Workpiece Roundness in the Shoe-Type Centerless Grinding Operation for Internal Raceway of Ball Bearings

One of the most important indices of bearing raceway, roundness, has an important influence on the life and performance of the bearing. Currently, shoe-type centerless grinding (STCG) is a core process for the fabrication of the raceway surface. Some researchers have carried out studies in this field; however, the reason and extent of the influence of process parameters on the workpiece roundness in the STCG operation for the internal raceway of the 6208 ball bearings are not clear up to now. In this paper, new research on the effects of process parameters on workpiece roundness in the STCG operation for the internal raceway of the 6208 ball bearings is presented. The influence of the angular placement of the two shoes, as well as the technology parameters including the offset between the rotational centers of the workpiece and the magnetic drivehead (e), the normal feed rate (Snf), the speed of the workpiece (nw), and the grinding depth (af), on the roundness of the raceway surface were investigated both theoretically and experimentally to solve the difficulties in the STCG operation to ensure the roundness of the raceway surface. Based on the research results, a guideline for selecting initial process parameters is introduced to ensure the roundness of the bearing raceway in the STCG operation for the internal raceway of 6208_ball bearings on the 3MK136B grinder.

Analysis of Dynamic Features of Gear–Bearing Systems with Bearing Raceway Failures

Analysis of Dynamic Features of Gear–Bearing Systems with Bearing Raceway Failures

Research on Non-Circular Raceway of Single-Row Four-Point Contact Ball Bearing Based on Life Optimization

The traditional slewing bearing with circular raceway has the problem of stress concentration under the large overturning moment. In this paper, a new non-circular raceway of a slewing ball bearing was presented to conquer this problem. To obtain the new non-circular raceway, first, the static equilibrium equations of the slewing ball bearing was established by the vector method, which is a constraint condition for life optimization; secondly, the life optimization function was established to calculate the contact load distribution in the bearing when the bearing life is at its maximum; finally, through the contact deformation with the contact load, the non-circular inner raceway corresponding to the maximum bearing life was obtained, and the non-circular shape corresponding to the raceway under axial load and overturning moment was studied. The results show that the non-circular raceway devised by this method can evenly reduce the contact force of the raceway and effectively improve the bearing capacity. Moreover, the position where the non-circular raceway deformation occurs is the position where the contact force is different before and after optimization. Therefore, the overturning moment has an effect on the shape of the raceway, whereas the axial load only affects the amplitude of the deformation, and has no obvious effect on the shape of the raceway.

Analysis of Contact Stress Distribution between Rolling Element and Variable Diameter Raceway of Cageless Bearing

The change in contact state between the rolling elements and raceway of a cageless bearing with a variable diameter raceway affect the wear of the bearing, which leads to discrete motion failure of the rolling elements. For this purpose, the contact characteristics as contact form and contact stress between the rolling elements and raceway were determined. A numerical method is proposed to determine the three-dimensional contact stress of a cageless bearing. First, combined with the variable diameter raceway structure characteristics and the motion of rolling elements, the rolling elements and raceway contact stress model was established, and the influence factors of contact stress and the maximum stress distribution were determined. Based on the rolling contact theory, the relative position of the stick-slip region and the tangential stress distribution of the contact area were analyzed. The stress equations for the three-dimensional between rolling elements and variable diameter raceway were obtained by the principle of superposition, and the stress component characteristics of the contact area were numerically simulated. The results show that the main influencing factors of contact stress are: load, structure of variable diameter raceway, spindle speed, friction coefficient µ and the ratio of the stick region and the slip region k. Taking a cageless bearing as an example, the influence of the contact curvature Ri on the contact stress is smaller than that of ri. Increasing ri to make it larger than 1.5 mm and controlling the speed to be lower than 13,950 r/min, the maximum stress appears in the conventional raceway, which is beneficial to alleviate the failure of the variable diameter raceway. There are a slip region and a stick region in the contact area, reducing the friction coefficient µ and increasing the stick-slip coefficient k appropriately can ensure the discrete movement of the rolling elements and reduce the wear of the variable diameter raceway. The error of the stress distribution model is less than 15%, which can predict and characterize the contact stress distribution between the rolling elements and the variable diameter raceway. The theoretical guidance for the development and application of cageless bearings is provided.

Application of Convolutional Neural Network for Fault Diagnosis of Bearing Scratch of an Induction Motor

The demand for the condition monitoring of induction motors is increasing in various fields, such as industry, transportation, and daily life. Bearing faults are the most common faults, and many fault diagnosis methods have been proposed using artificial pitting as the fault factor in most cases. However, the validity of a fault diagnosis method for other kinds of faults does not seem to be evaluated. Considering onsite scenarios and other possibilities of faults, this paper introduces scratches on the outer raceways of bearings. A study was performed on the detection of several kinds of bearing scratches using a proposed method that was based on an auto-tuning convolutional neural network. The developed approach was also compared with other diagnostic methods for validation. The results showed that the proposed technique provides the possibility of diagnosing several kinds of scratches with acceptable accuracy rates.

Combining the Finite Element Analysis and Kriging Model for Study on Laser Surface Hardening Parameters of Pitch Bearing Raceway.

Laser surface hardening is used to improve the fatigue performance of the large diameter pitch bearing. Determination of the process parameters by a trial and error method, depending on the experience of the technician, by changing the parameters repeatedly for each laser surface hardening process is time-consuming and costly. In this paper, a method of analyzing the maximum temperature and depth of a hardened layer during the laser surface hardening process for a pitch bearing raceway of a wind turbine is proposed, which combines finite element simulation and the Kriging model. A three-dimensional finite element model of a pitch bearing ring was established using ABAQUS. The temperature field analysis was performed. The effects of process parameters including laser power, scanning speed, and laser spot radius on the depth of the hardening layer were investigated. Then, taking into account the interactional effects of different process parameters, Kriging models were constructed to reflect the relationship between input process parameters and output responses. The results show that the Kriging approximation model has a small relative error compared with the simulated results and can be used to predict the hardened layer depth.

Micro-EDM Drilling/Milling as a Potential Technique for Fabrication of Bespoke Artificial Defects on Bearing Raceways.

The fabrication of bespoke artificial defects on bearing raceways helps in mimicking incipient faults during real application or for directly validating the diagnostic technology depending on their shapes and sizes. This is particularly useful when run-to-failure experiments are time-consuming and even difficult in some cases. However, there has been limited systematic research on the design and fabrication of artificial defects on bearing raceways, particularly for the purpose of accelerated testing. In this work, micro-EDM is put forward as a potential technique for the fabrication of artificial defects using drilling/milling mode. A methodology is developed, not only to achieve the full control of the dimension and distribution of defects on a bearing element, but also to qualitatively and quantitatively perform the efficient characterization of the defect surface. A linear regression model with the inclusion of two-way interactions based on an analysis of variance (ANOVA) is presented to optimally select the process parameters. The verification experiments show that this mathematical model obtains a good fit for approximately 80% of the observed data. Through a combination of optical microscopy and confocal microscopy, the morphology and topography of the artificial defects was measured and compared. To conclude, micro-EDM evidences its great potential in terms of machining efficiency, e.g., with an MRR of 0.060 , TWR of 0.032 and dimensional controllability, e.g., the standard deviation of pitting diameter and depth being 0.5 µm and 0.8 µm, respectively, to achieve a desirable feature shape for bearing defects.

Comparative study of bearing wear in spindle system at different working conditions

In order to analyze the bearing wear in the spindle system considering different speed and load conditions, a four-bearing spindle system was investigated. Two different working conditions, Case I and Case II, are considered. Case I condition has lower spindle speed and higher external loads and preload than Case II condition. Based on Archard model, a new wear depth model of angular contact ball bearing is presented which takes into account the influence of lubrication on bearing wear. The wear depths of inner and outer raceways for angular contact ball bearings are calculated based on the motion parameters and contact parameters of ball elements which are obtained by spindle system model. The effects of spindle speed, angular misalignment, external load and surface roughness on the wear depths of bearings are comparatively studied. Increasing spindle speed at Case I condition can significantly increase bearing wear. Angular misalignment may be beneficial to individual bearing, but overall, no angular misalignment is the most beneficial to spindle system. The change rate of wear depth of bearing raceway with external loads at Case I condition is much greater than that at Case II condition. The surface roughness can significantly affect the bearing wear in the spindle system, especially at Case I condition.

Modelling and Analysis of High-Speed Angular Contact Ball Bearing

Angular contact bearings are of primal importance in accommodating rotational mechanisms with high-speed characteristics. Their applications are centric to heavy axial and radial loads sustaining thrust loads to a single direction. In high-speed applications, factors such as centrifugal force, gyroscopic moments and relative displacements in various geometric features of the bearings are to be taken into consideration. This study focuses on establishing the contact angles, contact forces and spin speed for angular contact bearing to withstand varied rotational angular velocities. The forces experience a non-linear variation with respect to the body stiffness thus necessitating the involvement of numerical methods to converge at precise solutions through each juncture. The outer raceway of the bearing is accepted to be static with respect to the inner raceway as the input shaft for any application is predominantly affixed to the inner raceway of the angular contact bearing. Geometrical variations are determined under combined load conditions to simulate the natural working of the bearing at accelerated speeds. The analyses involve results for spatial parameters which are iteratively solved for each of the rolling elements in the bearing taken into concern. The spin speeds of the rolling elements are shown to dampen and exponentially increase with respect to their angular positions. The outputs manifested through this work can be utilized to accurately predict shift of salient design attributes of an angular contact bearings through low and high-speed applications.

Microstructure and Properties of Laser Cladding Martensitic Stainless Steel Coating on Large Wind-Power Bearing Raceway Surface

Microstructure and Properties of Laser Cladding Martensitic Stainless Steel Coating on Large Wind-Power Bearing Raceway Surface

Multi-Objective Optimization of Process Parameters to Enhance Efficiency in the Shoe-Type Centerless Grinding Operation for Internal Raceway of Ball Bearings

In this article, new research on the multi-objective optimization of the process parameters applied to enhance the efficiency in the shoe-type centerless grinding operation for the inner ring raceway of the ball bearing made from SUJ2 alloy steel is presented. The four important input parameters for this process, which included the normal feed rate of fine grinding (Snf), the speed of the workpiece (Vw), the cutting depth of fine grinding (af), and the number of ground parts (Np), were investigated. The aim of the study was to find the most appropriate value set of process parameters in order to, simultaneously minimize the grindstone wear (Gw), maximize the material removal rate (MRR) and the total number of ground parts in a grinding cycle (N’p), while guaranteeing other technology requirements such as surface roughness Ra ≤ 0.5 (µm), oval level Op ≤ 3 (µm), etc. In order to solve the problem, based on the experimental data, in which the grindstone wear was measured online by a measuring system consisting of two pneumatic probes, the optimization of the target functions of Gw, N’p, and MRR and mathematical models that express the dependencies of outcome parameters Gw, Ra, Op, MRR, etc. on the process parameters were determined. Therefore, a global optimal solution of such a discrete and nonlinear multi-objective optimization problem was solved by using a genetic algorithm, presenting the most appropriate process parameters as follows: Snf = 15.38 (µm/s), Vw = 6.00 (m/min), af = 11.76 (µm), and Np = 20 (parts/cycle). In addition, the impact of the four process parameters (Snf, Vw, af, Np) on the wear of the grinding wheel (Gw), the oval level of parts (Op), and the surface roughness of parts (Ra) was evaluated. The discovered technology mode has been applied to the real machining process for the inner ring raceway of the 6208_ball bearing made from SUJ2 alloy steel, and the outcome showed a much better result in comparison with default setting modes, while still ensuring the technology requirements. The difference between the predicted values and the real values of the parameters Gw, Ra, Op, and MRR were controlled within 5% of the ranges.

Aspekty transformacji eksploatacyjnej warstwy wierzchniej bieżni łożysk tocznych – przegląd

Wear of the top layer of the raceway of rolling bearings is a common problem in bearing operation. Its wear has been realized for over 50 years, but due to the use of rolling bearings in many industrial machines and technology development, it is necessary to constantly update the knowledge on this subject. The article reviews articles on the fatigue and tribological problems of the exploitation transformation of rolling bearings in terms of the current development trends in this field.

Research on Load Characteristics of Axle‐Box Bearing Raceway under Wheel‐Rail Excitation

With the increasing speed of high‐speed trains, the service conditions of axle‐box bearing system worsen, and meanwhile, the dynamic performance of the axle‐box bearing directly affects the operational safety. However, the dynamic interactions of the axle‐box bearing in the traditional vehicle‐track system are often ignored. In this paper, a vehicle‐track coupling dynamic model considering axle‐box bearing has been built, and the effectiveness of the model is proved by field tests. Dynamic performance of the axle‐box bearing has been analyzed and discussed through numerical simulations under different working conditions. Comparing the roller‐raceway contact load characteristics under different working conditions, results show that the peak values of roller‐outer raceway contact load with wheel‐polygonal excitation are basically the same with those without wheel‐rail excitation. However, most of the peak values of roller‐outer raceway contact force under track irregularity and comprehensive excitation conditions are far greater than those under wheel‐polygonal excitation and no wheel‐rail excitation conditions, which indicates that the impact of track irregularity on the contact load is dominant.

Investigations on Tailored Forming of AISI 52100 as Rolling Bearing Raceway

Hybrid cylindrical roller thrust bearing washers of type 81212 were manufactured by tailored forming. An AISI 1022M base material, featuring a sufficient strength for structural loads, was cladded with the bearing steel AISI 52100 by plasma transferred arc welding (PTA). Though AISI 52100 is generally regarded as non-weldable, it could be applied as a cladding material by adjusting PTA parameters. The cladded parts were investigated after each individual process step and subsequently tested under rolling contact load. Welding defects that could not be completely eliminated by the subsequent hot forming were characterized by means of scanning acoustic microscopy and micrographs. Below the surface, pores with a typical size of ten µm were found to a depth of about 0.45 mm. In the material transition zone and between individual weld seams, larger voids were observed. Grinding of the surface after heat treatment caused compressive residual stresses near the surface with a relatively small depth. Fatigue tests were carried out on an FE8 test rig. Eighty-two percent of the calculated rating life for conventional bearings was achieved. A high failure slope of the Weibull regression was determined. A relationship between the weld defects and the fatigue behavior is likely.

Experimental Assessment of Influence of the Ball Bearing Raceway Curvature Ratio on the Level of Vibration

Raceway curvature ratio is a very important parameter, because its values influence the performance characteristics of rolling-element bearings, their durability and the level of generated vibrations. However, the level of generated vibrations is one of the most important operating parameters of the rolling-element bearings. Excessive vibrations generated by rolling-element bearings affect the operation of the whole mechanism. The article presents experimental studies aimed at evaluation of influence of the inner and outer raceway curvature ratios of 6304-type rolling-element bearings on generated vibrations values. The raceway curvature ratio was determined based on results of metrological measurements. For this purpose, the radii of the inner and outer raceways as well as the diameters of the balls were measured. Design and principle of operation of an innovative system for analysis of the raceway geometry of the rolling bearing rings was presented. The vibration analysis was carried out in three frequency ranges, i.e. low (50-300 Hz), medium (300-1,800 Hz) and high (1,800-10,000 Hz). Values of measured vibrations were expressed in Anderon units. The test results showed that increase in the raceway curvature ratio causes a moderate decrease in the value of the generated vibrations. The research results presented in this article will serve as a guidance to designers and manufacturers of the rolling-element bearings on how to modify the geometry of raceways and balls to obtain bearings that generate low vibration values. That is very important in car transportation.