Tapered Roller Bearings Research Articles

Misalignment effect on gearbox failure: An experimental study

Overhang-meshing gears, deflection of pinion/gear shaft, bearing wear, assembly error, poor adjustment of bearings and foundation are the reasons of misalignment in gear drives.In the present work, the misalignment effect on gearbox failure is investigated experimentally using vibration analysis. Misalignment between motor and gearbox is measured using laser alignment system (LAS). The effect of input shaft speed and load on the gearbox failure is also discussed.The misalignment effect primarily observes on the gearbox drive end taper roller bearing and distresses gear transmission. Physical and microscopic examinations of the dismantle gearbox confirm similar findings as observe from vibration spectrum. Severe damages in taper roller bearing (32206) and multiple pits on all the rollers and cone. The bearing cage is deformed badly due to overload and misalignment. The effect of bearing failure on gear’s damage is also investigated. Non-uniform contact patch is observed on the meshing gears in the plane of action. Misalignment results in scuffing failure on the pinion addendum and gear dedendum regions due to limited lubricant in the overstress region. At the end of the test, all the four seals appears safe, while the coupling spiders damage seriously.

Effects of Bearing Locations on the Characteristics of a Spindle System Supported by Tapered Roller Bearings

This paper presents the effects of bearing locations on the mechanical characteristics of a multi-stepped spindle system related to bearing fatigue life, natural frequency, and static stiffness. The multi-stepped spindle is supported by a pair of tapered roller bearings (TRBs) and subjected to radial loading. To solve the equilibrium equation of the spindle system which is inherently statically-indeterminate, this study adopts an integrated shaft-bearing model, where the spindle is modelled by the finite shaft elements and the supporting TRBs are modelled by the five degrees-of-freedom TRB model developed by the authors. An iterative computational method is used to estimate the spindle deflection coupled with bearing deflections, and afterwards the bearing stiffness and internal contact loads of rolling elements are computed. The bearing fatigue life based on the ISO standard and the first natural frequency of the spindle system are evaluated with the spindle-bearing model. The influences of bearing locations on the static stiffness and natural frequency of the spindle, and the fatigue life of TRBs are rigorously investigated. The numerical results show the noticeable effects of bearing locations on the spindle system characteristics. The presented results provide a comprehensive assessment to aid for design optimization of spindle-TRB system.

Failure Investigation of Rear Axle Taper Roller Bearing by Using the Vibration Spectrum

Prevention of the occurrence of field failures of taper roller bearings under high-load and moderate-speed application is the prime challenge for bearing manufacturers. Failures result from numerous defects in bearing, such as localized or distributed defects. Various controls have been aligned in the manufacturing process to prevent outflow of defective bearings to end-application. However, still a part in million skips the controls in process and gets assembled in final application. In this literature, experiments are conducted to study the effect of grinding defect on cone track surface of taper roller bearing using the vibration spectrum, due to its peculiar unidentifiable nature in regular manufacturing process. Vibration analysis techniques are discussed in this case study. Statistical and spectrum analysis results are shared and concluded at the end of this case study.

Numerical Analysis of Grease Film Characteristics in Tapered Roller Bearing Subject to Shaft Deflection

The shaft deflection is one of critical factors that deteriorate the grease lubrication state inside the tapered roller bearings (TRBs). So, in this paper, on the premise of the TRB subjected to the combined loads and the shaft is deflected, the grease lubrication model at the TRB contacts was constructed, in which the interaction loads, linear and angular displacements of the bearing parts were involved. Then the grease film characteristics were numerically analyzed from the perspective of the whole bearing to clarify the negative effects of the shaft deflection on grease film characterizes. The results show that the effect of the shaft deflection on the load distribution in the absence of the radial load is greater than that in the presence of the radial load. The angular misalignment of the roller is mainly affected by the deflection. The deflection results in an irregular film shape and pressure profile at the TRB contacts, and induces a significant pressure spike and necking feature at the roller-end.

Robust optimum design of tapered roller bearings based on maximization of fatigue life using evolutionary algorithm

For satisfactory performance of rolling element bearings, they must be designed for long fatigue life. As the fatigue life of the bearings is directly affected by its dynamic capacity, therefore the latter has been chosen as an objective function, which is to be optimized using a robust design optimization. Robust design improves the quality of a product by optimising its mean performance and minimising variation in its performance that incurred due to uncertainties present with the product. Also at the same time, it maintains the design feasibility under realistic and probabilistic constraints. The uncertainties considered in this bearing design problem is the tolerance in bearing dimensions since bearings cannot be manufactured with the exact dimension. In this work, tapered roller bearings has been designed in such a way that it will have maximum dynamic capacity but along with it, it will have minimum variation in its dynamic capacity due to variation in basic dimensions. Therefore, objective of the problem is not to only maximize the dynamic capacity but also to minimise its variation to an extent level. A nonlinear constrained optimization problem has been formulated with single objective function, thirty realistic constraints and eleven design variables. Constraints are basically based on geometrical parameters and strength criterion. Out of total eleven design variables, five are geometrical parameters that directly affect the dynamic capacity and six are constraints parameters, which present in the constraints and affects the possible feasible design space. Real coded genetic algorithm has been used as an optimization tool and the result obtained are compared with the standard bearings in catalogue and that are indicating a drastic improvement in the bearing life. Their life is found to be on an average 1.5 times of the life of standard bearings in catalogues. A constraints violation study has been carried out to prioritise the constraints for faster convergence. A convergence study and sensitivity analysis have also been carried out. Convergence study ensured the global optima in the feasible design space. To perform sensitivity analysis, the variation of dynamic capacity with respect to all basic design variables, i.e. bearing pitch diameter, roller mean diameter, roller effective length and the nominal contact angle have been calculated. These are found to be a positive value indicating that dynamic capacity has a positive variation with respect to them. The same has been calculated for bearing 30,204 considering positive tolerance, the least variation is found 0.00018 times dynamic capacity, which is with respect to the bearing pitch diameter. Whereas, the most variation is 0.212 times dynamic capacity, which is with respect to the nominal contact angle. This shows that the bearing dynamic capacity is highly sensitive to the variation in nominal contact angle and least sensitive to the variation in bearing pitch diameter. Therefore, while manufacturing, the manufacturer should have more attention on contact angle. Finally, for visualisation, radial dimensions of optimized bearing 30,204 with positive tolerance have been drawn, showing no interference among the dimensions, which indicates a geometrically feasible design. Hence, the present paper allows a designer to design rolling bearings with maximum fatigue life and minimum variation in its performance due to tolerance accounted during manufacturing. The present problem is not limited to the bearings only, but can also be applied in optimization of any machine components (e.g. gears, cams, springs, etc.) having significant uncertainties in their materials or geometrical parameters such as modulus, thickness, residual strain, density, etc.

Multi-objective optimization in geometric design of tapered roller bearings based on fatigue, wear and thermal considerations through genetic algorithms

To improve the fatigue, wear and thermal based failures of Tapered Roller Bearings (TRBs) a multi-objective optimization technique has been proposed. Objective functions considered are: the dynamic capacity (Cd) that is related to fatigue life, the elasto-hydrodynamic minimum film thickness (hmin) that is associated to the wear life, and the maximum bearing temperature (Tmax) that is related to the lubricant life. This paper presents a non-linear constrained optimization problem of three objectives with eleven design variables and twenty-eight constraints. The said objectives have been optimized individually (i.e., the single-objective optimization) and concurrently (i.e., the multi-objective optimization) through a multi-objective evolutionary procedure, titled as the Elitist Non-dominated Sorting Genetic Algorithm. A set of standard TRBs have been selected for the optimization. Pareto-optimal fronts (POFs) and Pareto-optimal surfaces (POSs) are obtained for one representative standard TRB. Out of many solutions on the POFs/POSs only the knee-point solution has been shown in a tabular form. Life comparison factors have been calculated based on both the optimized and standard TRBs, and results indicate that the optimized TRBs got enhanced lives than standard bearings. To get the graphical impression of optimized TRBs, a skeleton of radial dimensions of all seven optimized bearings based on various combinations of objectives has been shown for one of the representative standard TRB. In few cases the multi-objective optimization has better convergence as compared to single objective optimization due to its inherent diversity by the principle of dominance. The sensitivity investigation has also been conducted to observe the sensitivity of three objectives with design variables. From the sensitivity analysis data, tolerances have been provided for design variables. These tolerances could be used by the manufacturing industry while producing TRBs.

Effects of Defect on Roller-Raceway Contact State and Friction Torque of Tapered Roller Bearings

Abstract The occurrence of defects is unavoidable during the service of tapered roller bearings (TRBs). Unfortunately, there is little information available in the literature about the mechanisms of effects of the defect on roller-raceways’ contact states and friction torque of tapered roller bearings. The present study first analyzed contact states of roller-raceways and roller-flange under the defective condition. A defected TRBs’ model was then established to obtain the contact load and corresponding contact pressure distribution between each roller and raceway, on the basis of which the friction torque of defected TRBs was evaluated. The results show that defects in the raceway edge induce a large contact pressure peak and uneven contact pressure distribution between roller and raceways. The defects presented on the outer raceway will cause a decrease in the friction torque of TRBs, and the decrement of friction torque is related to the external load and rotating speed of TRBs.

EFFECT ON STRESS AND THERMAL ANALYSIS OF TAPERED ROLLER BEARINGS

Due to high operational speed and more application of loads, the parts of the bearings may undergo fatigue. The parts are whirl movement in the cage and also for squeal movement and skidding and skewing. The wear will be more due to the dynamics of the bearings. Friction places importance on the dynamics and failure of the bearings. The computer modeling is done for the dynamic effects of the ball and cylindrical shape roller bearings. For better performance of the tapered roller bearing, the kinematic and geometric equations to be provided with both normal and axial loads. In this work to design of bearings (in this, we learn how the tapered roller bearing will work, what is the composition of material with which roller bearing is made. Analysis of bearings, in this, we will do ANSYS analysis, and it can find the stresses between the roller, inner, and outer ring. It would try to new lubricant (calcium-based grease) or recreate the design of bearings so that easy inlet of lubricants and easy outlet of lubricants. This research work is focused on a new coating material (ZEFFLE series), which is corrosive resistant and fretting wear.

A REVIEW ON LIFE INCREMENT OF TAPERED ROLLER BEARINGS

As day to day, life depends on the machine. Bearing plays a vital role, which is an essential component in the vast majority of devices. The objective of this project to investigate the current trends, challenges, and research needs relating to bearing life extension. In this case, the bearing life can be increased, and the performance of the product can be improved. The bearing design, analysis, development, and testing, along with the model-specific technical challenge imposed, will be discussed. The efficient usage of the equipment will be related to the life of the bearing. Also, the failure of life is another parameter to decide which lubrication and surface coating to be used. The presence of the tapered roller bearing can be increased by using a sufficient amount of lubricant, having good surface finish Heat treatment. Many stress and strain analysis are done on the bearings, and ways to reduce the misalignment is observed.

Fatigue life analysis of double-row tapered roller bearing in a modern wind turbine under oscillating external load and speed

Fatigue life analysis of roller bearing is usually performed for bearings under constant rotating speed and invariant loading conditions. For the bearings used in offshore floating direct-drive wind turbines, they often experience oscillating motions with varying loading patterns, for which the standard fatigue life analysis is not valid due to the presence of fluctuating loads. This paper presents the fatigue life analysis of a double-row tapered roller bearing under oscillating external load and speed conditions, which is used to support the main shaft of a large modern direct-drive wind turbine. First, a comprehensive quasi-static model of the double-row tapered roller bearing is developed for determining the internal load distribution of rollers. The contact pressure of rollers is then studied using an iterative scheme based on the elastic contact model. After that, the formulation of basic rating life of the double-row tapered roller bearing with oscillating external load and speed is given to calculate the fatigue life. Numerical simulations are carried out to investigate the effects of the oscillating load and speed, angular misalignment, and internal clearance on the fatigue life of the bearing.

Experimental and numerical roller skew in tapered roller bearings

This work investigates the roller skew of a tapered roller bearing. An experimental setup has been built to measure the roller skew angle in tapered roller bearings thanks to two inductive proximity sensors (IPS). Using the roller skew measured values, a numerical friction law at the rib-roller end contact is defined. In order to validate this friction model, the calculated skew angles are compared to the experimental values. The roller skew angle is calculated after the kinematic equilibrium analysis at each roller. Moreover, the effect of the load, inner-raceway rotational speed, oil temperature, and lubricant type on the skew is examined.

Experimental Estimation of Energy Losses in Tapered Roller Bearings

Experimental Estimation of Energy Losses in Tapered Roller Bearings

Tapered Roller Bearing Failure Diagnosis Based on Improved Probability Box Model

Bearing failure often occurs in rotating machinery. The fault diagnosis method based on the vibration signals has been studied for many years. This paper proposed an improved probability box (ip-box) modeling method for diagnosing bearing faults. The major theoretical principles involved with the probability box (p-box) modeling methods and a projection method. Since a larger aggregated width results in the p-box not being conducive to a fault identification and diagnosis, the mean of the focal element interval and the amount of data fluctuation between the adjacent focal elements were used as additional information. Then, the additional information was added to the ip-box model by the cooperative optimization method. Finally, the experimental results showed that the classification performance of a support vector machine (SVM) trained with eight measured values from the ip-box was significantly improved.

Trend of Technology for Automotive Needle Roller Bearings and Tapered Roller Bearings Contributing to Improvement of Fuel Efficiency

Trend of Technology for Automotive Needle Roller Bearings and Tapered Roller Bearings Contributing to Improvement of Fuel Efficiency

Fuel-efficient Tapered Roller Bearings for Axles in Off-road Vehicles

Fuel-efficient Tapered Roller Bearings for Axles in Off-road Vehicles

Signal Processing for Enhancing Impulsiveness Toward Estimating Location of Multiple Roller Defects in a Taper Roller Bearing

Abstract Rolling element defect identification is a difficult task. The reason being that defect on the rolling element has both rotational as well as revolutionary motion. To identify rolling element defect in a taper roller bearing, a novel signal processing scheme is proposed which results in a substantial increase in kurtosis and impulse factor of the vibration signal. The scheme constitutes a series of operations. In the beginning, the raw signal is decomposed by ensemble empirical mode decomposition (EEMD) and inverse filtering (INF). The above two stages of signal processing extract hidden impulses which are suppressed in the noise present in the experimental data. In the third stage of processing, continuous wavelet transform (CWT) using adaptive wavelet is applied to the preprocessed signal to produce a 2D map of the CWT scalogram. This transformation results in a higher coefficient in the region of impulse produced due to the defect. Finally, time marginal integration (TMI) of the CWT scalogram is carried out for defect localization. The defect frequency was evaluated with an accuracy of 97.81% and defect location was identified with an accuracy of 92%.

Analysis of Stresses in a Tapered Roller Bearing Using Three-Dimensional Photoelasticity and Stereolithography.

Digital photoelasticity is an important segment of optical metrology for stress analysis by digital photographic images. Advances in digital image processing, data acquisition, standard recognition and data storage allow the utilization of computer-aided techniques in the automation and improvement of the digital photoelastic technique. The objective of this study is to develop new techniques using 3D rapid prototyping with transparent resins in digital photoelasticity. Some innovations are proposed (e.g., a tapered roller bearing built with 3D rapid prototyping with transparent resin and the final assembly with the specimens prototyped separately). A metrology study is carried out with the new techniques developed.

Influence of Torque Load on Internal Load Distribution of Tapered Roller Bearings

The effect of simultaneous application of external torque load on the internal load distribution of tapered rolling bearings under axial and radial loads is studied. The radial deformation and axial deformation of the bearing under the torque load are studied, and the mathematical model of force balance of tapered roller bearing is established. Then the Newton-Raphson method is used to solve the established mathematical model, and the load distribution of the bearing under the two-direction and three-direction loads is obtained respectively. The influence of the torque load on the internal load distribution of the bearing is obtained by the global and local comparison analysis.

Internal loads and contact pressure distributions on the main shaft bearing in a modern gearless wind turbine

Abstract The double-row tapered roller bearing (TRB) widely used to support the main shaft in a modern gearless wind turbine is one of the main components and its faults can lead to the malfunctions and downtime of wind turbines. Over the past decades, some numerical approaches have been proposed for calculating the contact force and pressure distribution of double-row TRBs. Nevertheless, most of the existing studies did not take the angular misalignment between inner and outer rings and the frictional force between the rollers and raceways into account. This paper presents a comprehensive quasi-static model to investigate the internal load and contact pressure distribution in a double-row TRB by considering the angular misalignment, the combined external loads and frictional force. It is found that a small misalignment angle between inner and outer rings can result in a significant change in the magnitude and distribution of the contact force and pressure. The double-row TRB with crowned roller profile exhibits a substantial improvement in contact pressure distribution by eliminating the occurrence of pressure concentration. Moreover, the peak contact pressure can be significantly reduced on the roller with the crowned profile, even if in the case of misaligned bearing. Comparisons of the simulated contact loads and pressure distributions demonstrate the necessity of considering angular misalignment and frictional force in the modelling of large size and heavily loaded double-row TRB.

Experimental Investigation on Temperature Field of a Double-Row Tapered Roller Bearing

Based on the structural features of a double-row tapered roller bearing (DTRB), a test rig for multipoint temperature measurement was built to investigate the temperature filed characteristics of DTRB under different operating conditions. Firstly, the composition of the test rig and the measuring instruments are described and the loading method is introduced. Secondly, a multipoint temperature measurement method for inner and outer rings of DTRBs is introduced, including the arrangement of the sensors and the signal transmission. Finally, the influence of rotational speed and external load on the circumferential, axial, and radial temperature rise and temperature distribution in a DTRB is studied. Results show that for the stationary bearing outer ring, the temperature rise in the load zone is significantly higher than that in the non-load zone. Under combined load, there are obvious temperature differences in the axial, circumferential, and radial directions of a DTRB.