Ring Of Bearing Research Articles

FEATURES OF DIAGNOSING ROLLING BEARINGS BY THE ENVELOPE METHOD

The article is devoted to the work on identifying defects of the surface crack type by the vibrodiagnostic method of non-destructive testing using the envelope method on the example of a rolling bearing. Used in the work rolling bearings with a set of various surface defects: a roller crack and an outer ring crack along the rolling surfaces. The rolling bearing was installed in a test bench, which simulated its regular operation, with a fixed outer ring and internal ring rotated at a constant frequency. The features of the detection of the following specific defects are established: a roller crack, a crack in the outer ring, etc., as well as the correspondence of the calculated frequencies of the bearing elements to the actual ones obtained during the research. The norm/rejection criteria were obtained in a numerical value in relation to specific types of defects, namely: weak, strong defects of the rolling elements and the outer ring of the rolling bearing. The features of detecting specific defects by the envelope method, that depends on the pressure on the outer ring and its spatial location relative to the defect, are experimentally established.

Analysis of the Distortion of the Bearing Rings after Quenching

Bearings are usually used at high-speed and high-load conditions, so the bearing sleeve must be able to withstand large contact stress, which requires heat treatment. However, during the quenching process of the bearing sleeve, a vapor film is formed on the surface. Since the vapor film is not uniform along the axial direction during the process of boiling and breaking, it will cause uneven distortion of the bearing sleeve. This uneven distortion will cause the outer ring of the bearing to have elliptical distortion after heat treatment. However, the mechanism of this problem and how to reduce the elliptical distortion has not been completely solved. In this paper, two points on the inner wall and outer wall of the bearing sleeve in the orthogonal direction are measured by means of experiments, and the mechanism of the ellipticity distortion during the quenching process is revealed. Additionally, through its horizontal placement, oblique placement, and vertical placement, the cooling curve and cooling rate curve changes in the process of entering the quenching agent are studied; based on the cooling curve, the heat transfer coefficient of the bearing sleeve during quenching is obtained by the heat transfer equation. Input the heat transfer coefficient into the CAE heat treatment simulation software COSMAP, according to the Metallo-Thermo-Mechanics theory and the method of multi-field coupling, simulating the quenching process of GCr15 and 16MnCr5 materials. By comparison, the ellipticity value of the bearing placed at a 45° angle is smaller than that of the horizontally and vertically placed bearings, with the 16MnCr5 material having the smallest ellipticity value of 0.00016. The simulation results verified the distortion mechanism of the bearing sleeve during the quenching process and how to reduce the solution of elliptical distortion.

Identification of Subsurface Mesoscale Crack in Full Ceramic Ball Bearings Based on Strain Energy Theory

Subsurface mesoscale cracks exist widely in the outer ring of full ceramic ball bearings (FCBBs), which is a potential threat for the stable operation of related devices such as aero engines, food processing machinery, and artificial replacement hip joints. This paper establishes a dynamic model of subsurface mesoscale cracks in the outer ring of FCBBs based on strain energy theory, and the influence of different crack lengths on the running state is analyzed. The existence of mesoscale cracks is regarded as weakening on the stiffness coefficient, and the deterioration degree of outer ring stiffness of subsurface cracks is thereby quantified. It is found that a small wave peak appears in the vibration time-domain signal when there is a mesoscale crack on the outer ring subsurface, and the crack evolution is evaluated by the amplitude of the corresponding feature frequency. Finally, the accuracy of the model is verified by experiments. The model realizes the identification and degree evaluation of subsurface mesoscale cracks in FCBBs, and provides theoretical references for the diagnosis and status monitoring for FCBB rotor systems.

Theoretical study of effect of the geometrical parameters on the dynamic properties of the elastic rings of an air journal bearing

The paper investigates theoretically the effect of the geometry of the elastic rings of an air journal bearing on the elastic rings dynamic coefficients. The physical finite element method (FEM) model used to obtain the dynamic coefficients of the rings is discussed. A theoretical model is implemented to predict the effect of the geometrical parameters on the dynamic coefficients of the elastic rings. The effect of the geometrical parameters on the dynamic coefficients at different frequencies is studied using FEM. The elastic geometry that result in desired dynamic coefficients is demonstrated. Since predicting the dynamic coefficients for all possible ring geometries using FEM would be computationally expensive. A neural network (NN) is trained to predict the dynamic coefficients for all possible ring geometries generated by the different ring geometrical parameters within a given input domain. The NN results are compared to the experimentally verified FEM results and the results are in good agreement.

Surface topography of cylindrical precision grinding based on multi-source information fusion

In this study, spindle precision bearings and rotary vector (RV) reducer thin-walled bearings were taken as research objects. Based on the analysis of the metamorphic layer of bearings, the multidimensional research on the surface topography of parts by multisource information fusion (grinding force, grinding temperature, grinding strain, grinding vibration, and grinding acoustic emission (AE)) was put forward. The research shows that there are “dark layers” in the outer ring and inner ring of spindle precision bearings, and “white layers” and “dark layers” in the outer ring and inner ring of RV reducer thin-walled bearings. Feed speed has the greatest influence on grinding force, wheel speed, and grinding depth have the greatest influence on grinding temperature, wheel speed has the greatest influence on grinding strain, feed speed, and wheel speed have the greatest influence on grinding vibration, and workpiece speed has the greatest influence on grinding AE. When the grinding force is minimum ( x-axis: 1.3 N, y-axis: 0.9 N); the grinding temperature is highest (110.8°C), the grinding strain is maximum (46.6%), the grinding vibration is maximum (vibration range: 400 m/s2–400 m/s2) and the grinding AE is maximum (variation range: 2 V–1 V), the surface topography is most prominent (Ra: 0.97 μm). Grinding wheel speed and grinding depth have the greatest influence on surface topography, followed by feed speed, while workpiece speed has less influence.

Study of the Plastic Behavior of Rough Bearing Surfaces Using a Half-Space Contact Model and the Fatigue Life Estimation According to the Fatemi–Socie Model

A multiscale approach for the fatigue life estimation of rolling bearings is presented in this paper and applied to inner rings of cylindrical roller bearings of the type NU208. The forces acting in the rolling contact are determined from system-oriented modeling at the macro level. The microscale contact simulations are carried out in a half-space contact model. The stresses on the inner ring are determined and used in the local fatigue approach, according to Fatemi–Socie, for fatigue life estimation. Four surface variants were investigated, one ideally smooth surface and three real (rough) surfaces. The three rough surface variants used different finishing processes: fine ground, hard turned, and rough ground were produced. A load case with a maximum pressure of 2.4 GPa in the roller-inner ring contact was investigated. In addition to the fatigue life estimation, the plasticity behavior (surface topography, resulting contact pressure, and residual stress) of the three manufactured surfaces stood in the focus of the work. As the comparison between experimental and simulated results confirms, good predictions can be made with the simulation model.

Dynamic modeling and simulation analysis of inter-shaft bearing fault of a dual-rotor system

In order to study the vibration characteristics of inter-shaft bearing failures of a dual-rotor system, an eight-degree-of-freedom dynamic model of dual-rotor system containing inter-shaft bearings is established. The Newmark-β method is used to solve the proposed model equations. The dynamic characteristics of the rotor system when the inner ring and outer ring of the inter-shaft bearing has single-point failures or composite failures are analyzed. The comparison results show that the fault frequency distribution pattern in the envelope spectrum of the dynamic simulation results is consistent with that of the test results, which proves the effectiveness of the proposed dynamic model. It is found that when the inter-shaft bearing fails, a combination of rotor rotation frequency, multi-frequency, and fault frequency modulation frequency occurs in the fault characteristic frequency of the dual-rotor system. In addition to the speed-synchronized vibration components caused by the eccentricity, the rotor vibration signal is usually accompanied by a high-order harmonic vibration signal.

Impact of Technological System’s Characteristics on the Machining Accuracy of Bearing Rings

The article shows the influence of the technological system of an automated lathe, in particular cam chucks, on the accuracy of machining bearing rings for production conditions. The value of the deformation during machining, i.e., the non-circularity of the ring of a single row tapered roller bearing 32017X in outer diameter, was investigated. For the study, samples were selected that were processed under the same conditions directly in the production unit of PJSC “SKF Ukraine” without interference with the technological process. The use of replaceable floating cams in the chuck design was proposed to increase the accuracy and productivity of machining. Experimental studies have shown that the machined surface’s ovality depends on the chuck cams’ clamping force. The effectiveness of computer processing of statistical data on the accuracy control of engineering products was shown. Implementing machining accuracy control in production using the Minitab computer program was presented. It was proven that the quality of products is formed under the influence of the use of modern computer technologies at all stages of manufacturing and control of parts, which ensures research in a wide range of changes in technological parameters and comparison of individual studies with actual machining conditions on the machine, with the results of a sufficient level of reliability.

Physical and mechanical properties of anaerobic sealants

The article presents the main causes of wear on the seats of rolling bearings during operation, which are fretting corrosion and turning of the inner and outer rings of bearings. Installed that an effective way to protect metal surfaces from fretting corrosion is to place an intermediate medium between them. Coatings with a small modulus of elasticity are applied to one or both contacting surfaces to create an intermediate medium. Using anaerobic sealants as coatings with a small modulus of elasticity is recommended. Anaerobic sealants, which are multicomponent liquid compositions capable of remaining in the initial state for a long time without changing properties, quickly cure at temperatures of 20-25° C and in case of violation of contact with oxygen in the air with the formation of a durable solid polymer. The application technology of anaerobic sealants is presented, and the influence of temperature, talc, and copper on the physical and mechanical properties affecting the durability of fixed joints is studied. According to the results obtained, using the AN-6K and AN-103 brands of anaerobic sealants is recommended as the most effective for restoring fixed joints of rolling bearings and increasing their durability. The article substantiates the influence of temperature and various fillers on the physical and mechanical properties of anaerobic sealants; based on these results, the brands of sealants suitable for restoring fixed joints from rolling bearings are recommended.

Thin-Film Platinum Resistance Temperature Detector with a SiCN/Yttria-Stabilized Zirconia Protective Layer by Direct Ink Writing for High-Temperature Applications.

In situ temperature monitoring of curved high-temperature components in extreme environments is challenging for a variety of applications in fields such as aero engines and gas turbines. Recently, extrusion-based direct ink writing (DIW) has been utilized to fabricate platinum (Pt) resistance temperature detectors (RTDs). However, the current Pt RTD prepared by DIW technology suffers from a limited temperature range and poor high-temperature stability. Here, DIW technology and yttria-stabilized zirconia (YSZ)-modified precursor ceramic film packaging have been used to build a Pt RTD with high-temperature resistance, small disturbance, and high stability. The results indicate that the protective layer formed by the liquid phase anchors the Pt particles and reduces the agglomeration and volatilization of the Pt sensitive layer at high temperature. Attributed to the SiCN/YSZ protective layer, the temperature resistance curve of the Pt RTD in the range of 50-800 °C has little deviation from the fitting curve, and the fitting correlation coefficient is above 0.9999. Interestingly, the Pt RTD also has high repeatability and stability. The high temperature resistance drift rate is only 0.05%/h after 100 h of long-term testing at 800 °C and can withstand butane flame up to ∼1300 °C without damage. Moreover, the Pt RTD can be conformally deposited on the outer ring of aerospace bearings by DIW technology and then realize on-site, nondestructive, and real-time monitoring of bearing temperature. The fabricated Pt RTD shows great potential for high-temperature applications, and the novel technology proposed provides a feasible pathway for temperature monitoring of aeroengine internal curved hot-end components.

Development and stability analysis of a high‐speed train bearing system under variable speed conditions

AbstractDuring a high‐speed train operation, the train speed changes frequently, resulting in motion change as a function of time. A dynamic model of a double‐row tapered roller bearing system of a high‐speed train under variable speed conditions is developed. The model takes into consideration the structural characteristics of one outer ring and two inner rings of the train bearing. The angle iteration method is used to determine the rotation angle of the roller within any time period, solving the difficult problem of determining the location of the roller. The outer ring and inner ring faults are captured by the model, and the model response is obtained under variable speed conditions. Experiments are carried out under two fault conditions to validate the model results. The simulation results are found to be in good agreement with the results of the formula, and the errors between the simulation results and the experimental results when the bearing has outer and inner ring faults are found to be, respectively, 5.97% and 2.59%, which demonstrates the effectiveness of the model. The influence of outer ring and inner ring faults on system stability is analyzed quantitatively using the Lempel–Ziv complexity. The results show that for low train acceleration, the inner ring fault has a more significant effect on the system stability, while for high acceleration, the outer ring fault has a more significant effect. However, when the train acceleration changes, the outer ring has a greater influence. In practice, train acceleration is usually small and does not frequently change in one operation cycle. Therefore, the inner ring fault of the bearing deserves more attention.

Mechanism Design and Mechanical Analysis of Reconfigurable Wheel-track Wheel Based on Offset Guide Rod Mechanisms

According to different terrain characteristics, combined with the motion characteristics of wheeled and tracked mobile mechanisms, a reconfigurable wheel-track hybrid deformable wheel with multiple motion forms is proposed and developed. It is composed of a track, wheel body, slewing bearing, and conductive slip ring. In the wheel body, the deformation mechanism, braking mechanism, and turnover locking mechanism can make it realize four kinds of motion forms, such as wheeled form and triangular-tracked form. Based on the corresponding parameter model, the static and dynamic analysis of the deformation mechanism is carried out. Among them, the dynamic analysis puts forward two solutions to the rigid impact problem in the deformation process, and the second solution is systematically modeled. It is found that it can be expressed as a standard second-order system, and the simulation parameters are set according to its characteristics to verify the feasibility of the scheme.

Calculation and Analysis of Deformation Characteristic and Energy Dissipation of Flexible Bearings in Harmonic Drive for Industrial Robots

The flexible bearing is a key component of harmonic gear reducer for industrial robots. The wave generator cam as assembly part will significantly affect the flexible bearing transmission state. This paper derives the flexible bearing deformation coordination equation formula based on the harmonic drive theories, and the deformation characteristics of the flexible bearing formed by different wave generator cam shapes were studied. Combined the theory of clabellon with the load and deformation which are obtained, the deformation energy dissipation of the outer ring of the flexible bearing is discussed and quantitatively evaluated. The results showed that the wave generator cam shapes have a greater effect on the carrying capacity of the flexible bearing, and the dissipation of deformation energy of the flexible bearing can be effectively reduced by selecting appropriate wall thickness of the outer ring. Moreover, it was found that the two-roller wave generator deformation energy dissipation is the least at the same constraint.

Stability investigations of cageless ball bearings considering balls and outer rings with variable diameter raceways

The reducer raceway in the inner raceway of the outer ring of the cageless bearing can effectively make the rolling automatically discrete; nevertheless, it is unclear how this impacts the rolling. This work examines the influence of three types of reducer raceway structure form and prevent position on the mutual discrete stability of rolling bodies using numerical simulation and experiment. By analyzing the phase diagrams of rolling body velocity-displacement and inner ring velocity-displacement, it is discovered that the bearing area increases the stability of a single elliptical or shuttle-shaped local reducer raceway. The vibration of the elliptical reducer raceway bearing is the smallest and the rolling body discrete is the most stable, as determined by vibration testing of three forms of single reducer raceway ball bearings under varied working situations.

Angular Contact Ball Bearing Modeling with Different Types of Coatings

The purpose of this study is to determine the stress distribution of uncoated and coated ball bearings by using finite element analysis. The coatings used in this study are titanium nitride (TiN), titanium carbide (TiC) and chromium nitride (CrN) with a thickness of 5 microns. A contact analysis has been performed on ball bearings to compare the performance between coated and uncoated ball bearings. Boundary loads of 5000 N is used for contact analysis. This study tries to establish a simple, two-dimensional expression for the elastic deformation with the inner ring and ball bearing as a angular or curvature model in terms of the geometry of the coating contact surfaces. The coating of ball and raceway surfaces is a requisite but difficult factor to be determined during design, so it is desirable for engineering to understand the effect of surface coating on the motion of ball and subsurface stresses in bearing. For contact analysis, the maximum contact pressure and maximum stress on the coating, inner ring and ball bearing have been used for comparison. The results of this study show that, among other coatings, TiC provides the best protection for the ball of the ball bearing. This is because the low Poisson's ratio of TiC in other coated ball bearings helps reduce the stress on the ball bearing, even though TiC has the lowest Young's modulus in the coating. When a lower boundary load is applied, high COF will also cause an abnormal increase in the maximum stress on the contact surface between the coated or uncoated ball and the inner ring of the ball bearing.

Nonlinear dynamic correlation between balls, cage and bearing rings of angular contact ball bearings at different number of balls and groove curvature radii

Nonlinear dynamic correlation between balls, cage and bearing rings of angular contact ball bearings at different number of balls and groove curvature radii

Whole surface defect detection method for bearing rings based on machine vision

As an important part of a bearing, a bearing ring (BR) is prone to producing various defects on each surface in the production process, which seriously affects the reliability of the bearing. To solve the problem in which multiple defects are randomly distributed on multiple surfaces and manual detection is difficult, an automatic method for detecting defects on the whole surface of BRs based on machine vision is proposed. Firstly, the characteristics of the BR’s surface defects are analyzed, and an efficient scheme for acquiring the whole surface image of the BR is designed. Then, the method for detecting the defects on the whole surface of BRs is developed, and the corresponding image preprocessing, region of interest extraction and defect recognition algorithms are designed. Finally, a visual inspection system to identify the defects on the whole surface of BRs based on a multi-station turnover process is developed. On the premise of determining the key parameters of the detection algorithm, the performance of the detection method is analyzed through the experimental method. The results show that the comprehensive accuracy of the proposed detection method is 95%, which meets the detection requirements. On this basis, the detection strategy is optimized, and the best parameter combination is obtained through the experiments, which further reduces the false detection rate of good products and the missed detection rate of defective products, both of which are less than 3.5%.

Challenges of Numerical Simulation Models for Induction Surface Hardening of Large Bearing Rings

Abstract Induction hardening of large bearing rings is a very challenging procedure due to the complex physical processes and their interactions, which need to be properly controlled to produce components meeting the imposed requirements of e.g. wind turbines. The different process parameters significantly alter the resulting microstructures and properties of such a bearing ring. The evolution of numerical simulations in the last decades allows the modelling of processes with a growing complexity. In this work, the challenges of a simulation model for induction surface hardening are shown and discussed. Besides the theoretical background of the interacting physical fields and a brief note about available software packages, the paper focusses on the elaboration of a necessary material database and on the specific problems of induction scan hardening processes for large bearing rings.

Defect Size Evaluation of Cylindrical Roller Bearings with Compound Faults on the Inner and Outer Races

Faults in cylindrical roller bearings are one of the main contributors to major faults in rotating machinery. The development of bearing fault diagnosis technologies is key to measuring the performance, status, and risk of failure of rolling-element bearings and has attracted extensive attention from industry and academia. When faults arise, they are often not a single fault but a compound fault, such as the simultaneous failure of the inner and outer races. In this paper, a method for evaluating the size of compound faults on the inner and outer races of cylindrical roller bearings is proposed. The dynamic modeling method developed by Gupta is employed to create a dynamic model for compound faults on the inner and outer rings of rolling bearings that allows the time domain signal of the vibration responses of compound faults on the inner and outer races to be obtained. Adopting an improved continuous harmonic wavelet packet decomposition method for the decomposition and reconstruction of the compound fault signal, we arrive at the corresponding single-point fault signal. The relationship between defect size and key metrics of the vibration, such as root mean square acceleration (RMS), peak, crest factor (CF), kurtosis, and level crossing rate (LCR), is investigated. The results show that there is a strong linear correlation between LCR and defect size, which can be used to evaluate the size of the defect. Experimental data for cylindrical roller bearings with compound faults on the inner and outer races are examined to verify the results.

Using Multivariate Quality Statistic for Maintenance Decision Support in a Bearing Ring Grinder

Grinding processes’ stochastic nature poses a challenge in predicting the quality of the resulting surfaces. Post-production measurements for form, surface roughness, and circumferential waviness are commonly performed due to infeasibility in measuring all quality parameters during the grinding operation. Therefore, it is challenging to diagnose the root cause of quality deviations in real-time resulting from variations in the machine’s operating condition. This paper introduces a novel approach to predict the overall quality of the individual parts. The grinder is equipped with sensors to implement condition-based maintenance and is induced with five frequently occurring failure conditions for the experimental test runs. The crucial quality parameters are measured for the produced parts. Fuzzy c-means (FCM) and Hotelling’s T-squared (T2) have been evaluated to generate quality labels from the multi-variate quality data. Benchmarked random forest regression models are trained using fault diagnosis feature set and quality labels. Quality labels from the T2 statistic of quality parameters are preferred over FCM approach for their repeatability. The model, trained from T2 labels achieves more than 94% accuracy when compared to the measured ring disposition. The predicted overall quality using the sensors’ feature set is compared against the threshold to reach a trustworthy maintenance decision.