High-speed Cylindrical Roller Bearing Research Articles

Analysis and experimental research of transient temperature rise characteristics of high-speed cylindrical roller bearing

In this paper, on one hand, the time-varying characteristics of the heat source and thermal boundary conditions of the high-speed spindle system were analyzed considering the thermal-structural coupling effect. And a transient bearing temperature field prediction method combining the thermal network method and finite element method was proposed. Furthermore, the relationships between time step, calculation efficiency and calculation results were analyzed. On the other hand, a online real-time monitoring system of the transient temperature of the cylindrical roller bearing inner ring for maximum speed of 13,000 r/min was designed and implemented using fibre optic sensing technology. Comparing with the conventional static thermal analysis results, it is verified that the simulation method proposed in this paper has higher accuracy. This paper provides a new approach for analysing and testing the thermal characteristics of high-speed spindle system.

Micro-geometry deviation to reduce the cage slip of high-speed cylindrical roller bearings

Micro-geometry deviation to reduce the cage slip of high-speed cylindrical roller bearings

A fatigue failure investigation and improvement of a high-speed cylindrical roller bearing in a turbofan engine

High-speed cylindrical roller bearings are critical components used in turbofan engines. The failures in the cylindrical roller bearings are common failure cases in the turbofan engines due to the tough speed and load conditions, which can increase downtime and create an enormous loss. Thus, it is necessary to understand the failure reasons including the careless handling, improper clearance or mounting, ineffective sealing, and unsuitable lubrication. This paper introduces a failure analysis of a high-speed cylindrical roller bearing used in the turbofan engine. A detailed analysis of high-speed cylindrical roller bearing failures is proposed by using the finite element method. The failure reasons are identified as the manufacturing errors in the effective length of the inner ring, which led to the high-stress concentrations at the two ends of the roller resulting in fatigue failures. The failure mechanisms are understood. The optimization design of the structure to avoid the failures is presented. The validation test shows that the prevention strategies for similar failures are addressed. This paper can provide some guidance for analyzing and identifying the spalls and wear failures in the high-speed cylindrical roller bearings used in the turbofan engines.

Abnormal Wear Mechanism and Improvement of High-Speed Cylindrical Roller Bearing

This paper presents the dynamic differential equations of cylindrical roller bearing, considering the dynamic unbalance mass of roller and the contact between the roller end face and the inner ring rib. The influence of bearing working condition and structural parameters on the P V value of roller end face and the slip speed of roller working surface were analysed. The theoretical analysis and experimental results both show that the large amount of roller’s dynamic unbalance mass due to the difference in chamfering size on both sides of the roller and the deviation of the bearing axial clearance are the main causes of abnormal wear on the roller working surface and end face.

Lubrication and Fatigue Life Evaluation of High-Speed Cylindrical Roller Bearing under Misalignment

This paper developed a coupled model, incorporating the quasistatic model, fatigue life model, and mixed lubrication model, to investigate the effect of misalignment angle on high-speed cylindrical roller bearings. The model is verified by comparing with the published literature results. Then, a parametric analysis is carried out. The results show that as the misalignment increases, the load distribution is basically unchanged, but the fatigue life of the roller bearing decreases due to the variation of contact pressure, and the skewing moment of single roller contact pair increases. Furthermore, the optimal design of roller profile needs to consider the effect of lubrication in order to improve the fatigue life of roller bearings. In general, the optimal crown drop is too small according to the design from the slicing technique.

Vibration response analysis of high-speed cylindrical roller bearings using response surface method

The operating clearance in a bearing influences friction, load zone size and fatigue life of a bearing. Hence, an effort is made to investigate the effect of radial internal clearance on the dynamical behavior of a cylindrical roller bearing system with an unbalance present in the system. The differential equations representing the dynamics of the cylindrical roller bearings have been derived using Lagrange’s equations and solved numerically using the fourth-order Runge-Kutta iterative method. The nonlinear vibration signature has been analyzed due to the clearance and the same is represented by various tools like Acceleration-time plots, Poincaré plots and FFT plots. The approximation method is used to calculate the load distribution and deformation of the individual rollers located at a different position in the load zone, for a preloading/interference fit and positive internal clearance. A response surface method is used to analyze the severity involved in the system due to the combined effect of independent variables like rotor speed, radial load, and radial internal clearance. The observations presented here are not only useful to diagnose the bearing health condition with respect to parametric effects but also exhibit their interactive effects on bearing performance.

Effect of cage dynamic unbalance on the cage’s dynamic characteristics in high-speed cylindrical roller bearings

Purpose The purpose of this paper is to study the influence of the cage dynamic unbalance on the dynamic performances in cylindrical roller bearings. Design/methodology/approach The dynamic analysis model which considering cage dynamic unbalance is presented, and the relationship between the cage dynamic unbalance and the cage stability, the cage slip ratio and the cage skew angle is investigated. Findings Cage dynamic unbalance has a great effect on the cage stability. The cage dynamic unbalance which in an axial excursion affects the cage characteristics is greater than that only in the radial direction. The cage slip ratio and the cage skew increases with the cage dynamic unbalance, especially with the axial excursion. The non-metal cage is more sensitive to the cage dynamic unbalance than that of the metal cage. Originality/value The analytical method and model can be applied by the bearing engineering designers.

Effect of roller dynamic unbalance on cage stress of high-speed cylindrical roller bearing

PurposeThe purpose of this study is to investigate the effect of roller dynamic unbalance on cage stress.Design/methodology/approachConsidering the impact of roller dynamic unbalance, the dynamic analysis model of high-speed cylindrical roller bearing is established. And then the results of dynamic model are used as the boundary conditions for the finite element analysis model of roller and cage to obtain the cage stress.FindingsRoller dynamic unbalance affects the contact status between roller and cage pocket and causes the overall increase in cage stress. The most significant impact on cage stress is roller dynamic unbalance in angular direction of roller axis, followed by radial and axial directions. Smaller radial clearance of bearing and a reasonable range of pocket clearance are beneficial to reduce the impact of roller dynamic unbalance on cage stress; the larger cage guide clearance is a disadvantage to decrease cage stress. The impact of roller dynamic unbalance on cage stress under high-speed condition is greater than that in low-speed conditions.Originality/valueThe research can provide some theoretical guidance for the design and manufacture of bearing in high-speed cylindrical roller bearing.

Vibration effect analysis of roller dynamic unbalance on the cage of high-speed cylindrical roller bearing

This paper presents a nonlinear dynamic differential equations of high-speed cylindrical roller bearing considering the impact of roller dynamic unbalance. The cage vibration characteristics are investigated as a function of roller dynamic unbalance, structure parameters and working conditions. The fast Fourier transformation, cage orbit and vibration acceleration level are used to evaluate the vibration magnitude of the cage. The results show that: (1) Roller dynamic unbalance can affect the state of the cage motion and cause the cage's vibration acceleration level to increase. Once the roller dynamic unbalance exceeds a threshold, the cage will produce a high frequency vibration; (2) The most significant impact on the cage vibration is roller dynamic unbalance in angular direction of roller axis, followed by radial and axial direction; (3) A smaller radial clearance and a reasonable pocket clearance are beneficial to reducing the effect of roller dynamic unbalance on the cage vibration. It is recommended to take a larger cage-race guide clearance within a certain range to lower the cage vibration; (4) The cage vibration due to the roller dynamic unbalance increases with the bearing speed, and is greater than that of the cage with ideal roller. The effect of roller dynamic unbalance on the vibration of cage under high-speed condition is greater than that of the low-speed condition. The increase of the radial load of the bearing, to a certain extent, can reduce the vibration of cage considering the roller dynamic unbalance.

The effect of round corner on lubrication of high speed cylindrical roller bearings considering skidding

PurposePrevious studies were mainly focused on profile designation of bearing rollers and lubrication performance without considering roller-races skidding. However, the width of round corner, load, rotational speed and some other parameters have significant effects on the roller-races sliding speed. This paper aims to investigate the effect of round corner on lubricating characteristics between the heavily loaded roller and inner race considering skidding and roughness.Design/methodology/approachA mixed elastohydrodynamic lubrication (EHL) model which is capable of handling practical cases with 3D machined roughness is combined with the skidding model to investigate the effect of round corner on lubricating characteristics between the heavily loaded roller and inner race.FindingsThe width of round corner and round corner radius have a desirable range under certain operating condition, within which the maximum pressure, stress and maximum flash temperature remain low. The optimized range is sensitive to the operating condition. Roughness and skidding narrow the optimized range of round corner radius. Roughness increases the pressure peak, Mises stress and friction coefficient. At the same time, skidding and roughness have obvious effects on film thickness at the contact center area if the round radius is small.Research limitations/implicationsThis paper uses the Harris skidding model that has a relatively bigger error, which is not accurate if the bearing load is less.Practical implicationsThis paper unifies the skidding model and mixed EHL model which can be used as a tool for optimization design and lubricating performance analysis of cylindrical roller bearing.Originality/valueLubrication analyses for roller bearing are assumed to be pure rolling contact between roller and races in a previous study, which could not reflect the real contact characteristics. The skidding model is merged into a mixed EHL model which can be used as a dynamic tool to analyze the lubricating performance considering the round corner, skidding and roughness.

Influence of Lubricant Traction Coefficient on Cage's Nonlinear Dynamic Behavior in High-Speed Cylindrical Roller Bearing

In this paper, the formulas of elastohydrodynamic traction coefficients of four Chinese aviation lubricating oils, namely, 4109, 4106, 4050, and 4010, were obtained by a great number of elastohydrodynamic traction tests. The nonlinear dynamics differential equations of high-speed cylindrical roller bearing were built on the basis of dynamic theory of rolling bearings and solved by Hilber–Hughes–Taylor (HHT) integer algorithm with variable step. The influence of lubricant traction coefficient on cage's nonlinear dynamic behavior was investigated, and Poincaré map was used to analyze the influence of four types of aviation lubricating oils on the nonlinear dynamic response of cage's mass center. The period of nonlinear dynamic response of cage's mass center was used to assess cage's stability. The results of this paper provide the theoretical basis for selection of aviation lubricating oil.

Bubble Flow Analysis of High Speed Cylindrical Roller Bearing under Fluid-Solid Thermal Coupling

Heat generation model of high speed cylindrical roller bearing is constructed by calculating the local friction in the bearing. Bubble flow calculation model of roller bearing considering fluid-solid thermal coupling is constructed based on two-body fluid model and k-ε turbulent model, in which diameter and size of bubbles, breakup, and coalescence model of bubbles are considered. Using dynamic mesh method, a new method for evaluating bearing temperature is set up treating the rolling elements as moving heat sources. Based on these models and finite element method, bubble flow of a high speed roller bearing is studied based on FLUENT software. The numerical study reveals the relationship between velocity of bearing, air volume fraction, and velocity and pressure of oil-air flow. An increase of air content in the oil produces a lower pressure at the bearing outlet while the exit fluid velocity increases. When fluid-solid thermal coupling effect is considered, velocity and pressure at outlet of the bearing both become larger, while temperature of bearing is lower than that without coupling. In comparison, the coupling effects on flow pressure and temperature are obvious. For a given rotating speed, there is an optimal value for air volume fraction, such that temperature rise of the bearing reaches the lowest value. Experiments verify the outcomes of the method presented in this paper.

Study on the impact of roller convexity excursion of high-speed cylindrical roller bearing on roller's dynamic characteristics

This paper presents dynamics differential equations of high-speed cylindrical roller bearing considering the impact of roller convexity excursion on mass center of roller, which are solved by GSTIFF (Gear Stiff) integer algorithm with variable step. The impact of roller convexity excursion on roller's dynamic characteristics is investigated theoretically, and the accuracy of dynamic model of high-speed cylindrical roller bearing and the computation results are demonstrated via Caba3D. The findings are as following: 1) Roller convexity excursion has tiny impact on tilting angle of roller but great impact on skewing angle, and the bigger convexity excursion the bigger skewing angle; 2) For PCRC(partially crowned roller with the center of crowned profile locating at the center line of roller), PCRE(partially crowned roller with the center of crowned profile locating at the ends of roller), fully crowned roller and logarithmic crowned roller, the amounts of roller convexity excursion are less than 0.6mm, 0.4mm, 0.4mm and 0.4mm, respectively; 3) The sensitivity to roller convexity excursion for four types of rollers is different, and the sensitivity level of roller from small to large is logarithmic crowned roller, PCRE, PCRC, fully crowned roller. 4) Among four types of crowned rollers, anti-speed capability and anti-load capability of logarithmic crowned roller are the most excellent, followed by PCRE and PCRC, and fully crowned roller is the worst one in both aspects.

Chaotic Dynamics of Cage Behavior in a High-Speed Cylindrical Roller Bearing

This paper presents a mathematical model to investigate the nonlinear dynamic behavior of cage in high-speed cylindrical bearing. Variations of cage behavior due to varying cage eccentricity and cage guidance gap are observed. Hydrodynamic behavior in cage contacts is taken into consideration for a more realistic calculation of acting forces owing to high working speed. Analysis of real-time cage dynamic behavior on radial plane is carried out using chaos theory based on the theoretical and mathematical model established in the paper. The analytical results of this paper provide a solid foundation for designing and manufacturing of high-speed cylindrical roller bearing.

Analysis on Dynamic Characteristics of High Speed Cylindrical Roller Bearing

A nonlinear dynamics analysis mathematical model for the high-speed cylindrical roller bearing was built up. Dynamic performance parameters were got by Newton - Raphson method . The rotational velocity regularities of rollers were analyzed at different radial loads. The distribution of minimum oil-film thickness and contact load between rollers and bearing ring raceway were obtained. The results showed that number of loaded rollers increased with the increase of radial loads at a certain speed. Rollers slip seriously at lower radial loads. The rotation speed was low. The minimum oil-film thickness between loaded rollers and inner raceways was less than that of outer raceways. The results were compared with the results of SHARBERTH and comparison was made with testing results. It showed that the dynamic characteristics analysis method of high speed cylindrical roller bearing was accurate, reliable,simple and convenient for practical engineering application.

Theoretical Analysis of High-Speed Cylindrical Roller Bearing with Flexible Rings Mounted in a Squeeze Film Damper

For high-precision mechanical systems such as gas-turbine engines that operate under extreme conditions, it is particularly important to accurately predict the behavior of the mainshaft rolling bearings. This prediction includes, among others, the load distribution, stiffness, and power dissipation. Although the shaft speeds tends to increase, rings and shaft are becoming thinner due to size and weight constraints. Thus, the bearing behavior is now dependent on the housing and ring stiffness. Furthermore, the use of a squeeze film damper (SFD) is widespread in gas-turbine engines to significantly reduce the vibratory levels. In this case, a single thin ring provides the interface between the bearing rolling elements and the fluid film. Due to the flexibility of this ring, an elastic coupling occurs modifying the behavior of the bearing-SFD system. A global flexible bearing-SFD assembly model is proposed in this paper. Large deformations can occur, resulting in a contact between the ring common to the bearing and the SFD and its housing. To reproduce this interference, an effective mechanical stop model is also proposed. The behavior of an industrial bearing-SFD assembly is then investigated for different operating conditions. The presented results show that this coupling has a first-order influence on the behavior of the bearing-SFD system. It is also shown that such elastic coupling introduces a dissymmetry of the load distribution with respect to the applied load direction. Moreover, in certain cases, the position of the bearing in its housing can reach eccentricities larger than the radial clearance of the SFD.

Modeling of Instabilities Induced by Cage Clearances in Cylindrical Roller Bearings

The classical differential equations of motion for the rollers and cage, in a high-speed cylindrical roller bearing, are integrated under prescribed operating conditions and bearing geometry. The generalized cage motion is parametrically evaluated as a function of clearances both in the cage pockets and at the cage-to-race guide lands. Definite correlations between certain cage instabilities and the operating clearances provide practical guidance for optimization of cage clearances for a given performance specification. Presented at the 45th Annual Meeting in Denver, Colorado May 7–10, 1990

Analysis of High-Speed Cylindrical Roller Bearings Using a Full Elastohydrodynamic Lubrication Model Part 1: Formulation

This paper presents the formulation and use of an elastohydrodynamic (EHD) lubrication model to analyze the kinematic and dynamic behavior of highspeed cylindrical roller bearings. The analysis program developed incorporates a computational algorithm that can efficiently and accurately find the pressure distributions and film-thickness profiles in the roller-raceway contacts as the roller traverses in the race tracks. The internal load distribution, bearing stiffness, running torque, and amount of roller skidding can be calculated for different applied loads, operating speeds, internal clearances, and lubricant properties. The effects of manufacturing imperfections can also be analyzed in terms of outer-raceway waviness and roller diametral tolerance. The results are presented in Part II of this two-part paper.

Analysis of High-Speed Cylindrical Roller Bearings Using a Full Elastohydrodynamic Lubrication Model Part 2: Results

The kinematic and dynamic characteristics of high-speed cylindrical roller bearings are analyzed using the elastohydrodynamic (EHD) lubrication model developed in Part I of this two-part paper. The internal load distribution, bearing stiffness, running torque, and amount of roller skidding are calculated under various operating conditions. Effects of manufacturing imperfections are also analyzed in terms of outer-raceway waviness and roller diameter tolerance. Results obtained through case studies indicate that the behavior of the bearing can be significantly affected by EHD lubrication in the roller-raceway contacts. Presented at the 44th Annual Meeting in Atlanta, Georgia May 1–4, 1989

On the Frictional Instabilities in a Cylindrical Roller Bearing

Computer simulations of a high-speed cylindrical roller bearing, as obtained by the computer code ADORE, are used to correlate bearing performance to the frictional behavior at the roller/race and cage contacts. It is shown that an optimum traction-slip relation at the roller/race contacts may be determined to produce minimum race wear and heat generation in the bearing. Unlike the well defined circular cage mass center whirl orbits commonly seen in ball bearings, no significant cage whirl was found in a lightly loaded cylindrical roller bearing over the range of frictional parameters considered.