The Rotational Accuracy Characteristics of the Preloaded Hollow Roller Bearing

1981 ◽  
Vol 103 (1) ◽  
pp. 6-12 ◽  
Author(s):  
C. P. Bhateja ◽  
R. D. Pine
Keyword(s):  
Roller Bearing ◽  
Design Parameters ◽  
Annular Space ◽  
Dynamic Nature ◽  
Cyclic Pattern ◽  
Radial Bearing ◽  
Geometrical Features ◽  
Present Context ◽  
Rolling Elements ◽  
Inner Race

The rotational characteristics of the cageless, hollow roller radial bearing are investigated. The preloading of the hollow rolling elements in the annular space between the inner and the outer races in such a bearing provides a well controlled and consistent shaft rotational pattern. This pattern is determined by the dimensional and geometrical features of the rollers’ external and internal diameters and roundnesses, the outer and inner ring raceway roundnesses and the eccentricity of the inner race with respect to the shaft axis. The various patterns of shaft runout associated with these causes are identified and the sensitivity of the shaft runout to these factors is examined qualitatively and quantitively. The shaft runout in the present context is not merely the initial static offset of the shaft axis, but is a dynamic, cyclic pattern consisting of certain frequencies resulting from the geometrical features of the bearing components. The somewhat elusive, complex and dynamic nature of this apparent shaft runout makes it difficult to be measured. In addition, the importance of the need to control the circumferential clearance to a minimum is demonstrated. It is thus shown that through the proper control of the component geometry and certain design parameters, the hollow roller bearing can provide an extremely accurate bearing for precision applications.

DETERMINATION OF ROLLER BEARING INNER RACE DEFECT BASED ON VIBRATION SIGNAL

2019 ◽  
Vol 24 (3) ◽  
pp. 467-475
Author(s):  
Mohamed El Morsy ◽  
Gabriela Achtenova
Keyword(s):  
Time Domain ◽  
Roller Bearing ◽  
Vibration Signal ◽  
Rolling Bearing ◽  
Band Pass Filter ◽  
Bearing Defect ◽  
Rolling Elements ◽  
Characteristic Features ◽  
Bearing Characteristic ◽  
Inner Race

The present article’s intent is to measure and identify the roller bearing inner race defect width and its corresponding characteristic frequency based on filtered time-domain vibration signal. In case localized fault occurs in a bearing, the rolling elements encounter some slippage as the rolling elements enter and leave the bearing load zone. As a consequence, the incidence of the impacts never reproduce exactly at the same position from one cycle to another. Moreover, when the position of the defect is moving with respect to the load distribution zone of the bearing, the series of impulses are modulated in amplitude in time-domain and the conforming Bearing Characteristic Frequencies (BCFs) arise in frequency domain. In order to verify the ability of time-domain in measuring the fault of rolling bearing, an artificial fault is introduced in the vehicle gearbox bearing: an orthogonal placed groove on the inner race with the initial width of 0.6mm approximately. The faulted bearing is a roller bearing quantification of the characteristic features relevant to the inner race bearing defect. It is located on the gearbox input shaft—on the clutch side. To jettison the frequency associated with interferential vibrations, the vibration signal is filtered with a band-pass filter based on an optimal daughter Morlet wavelet function whose parameters are optimized based on maximum Kurtosis (Kurt.). The residual signal is performed for the measurement of defect width. The proposed technique is used to analyse the experimental signal of vehicle gearbox rolling bearing. The experimental test stand is equipped with two dynamometer machines; the input dynamometer serves as an internal combustion engine, the output dynamometer introduces the load on the flange of the output joint shaft. The Kurtosis and Pulse Indicator (PI) are selected as the evaluation parameters of the de-noising effect. The results show the reliability of the proposed approach for identification and quantification of the characteristic features relevant to the inner race bearing defect.

A Multiphase Computational Study of Oil-Air Flow Within the Bearing Sector of Aeroengines

2015 ◽  
Author(s):  
Akinola A. Adeniyi ◽  
Hervé P. Morvan ◽  
Kathy A. Simmons
Keyword(s):  
Boundary Conditions ◽  
Computational Study ◽  
Roller Bearing ◽  
Operating Conditions ◽  
Rolling Contact ◽  
Contact Friction ◽  
Outer Race ◽  
Roller Bearings ◽  
Rolling Elements ◽  
Inner Race

The bearing chamber of an aeroengine houses roller bearings and other structural parts. The spatial limitation, high operational speeds of the HP shaft and the proximity to the combustion chamber can make the operating conditions of the bearing chamber challenging. A roller bearing consists of an inner race, an outer race and a cage constraining a number of rolling elements. In the aeroengine application, oil is introduced into the bearing chamber via the inner race regions of the bearing into the rolling elements interstices. This provides lubrication for the roller bearings. The source of heat in the bearing chamber is mainly from rolling contact friction and the high temperature of combustion. Cooling results from the oil transport within the bearing chamber and thus an efficient transport of oil is critical to maintaining the integrity of the entire structure. The bearing chamber contains the oil which is eventually scavenged and recycled for recirculation. Experiments have been conducted over the years on bearing chamber flows but often simplified to create the best emulation of the real aeroengine. The complexity of the bearing chamber structure is also challenging for experimental measurements of the oil characteristic in the roller bearing elements and the bearing chamber compartment. Previous experiments have shown that the oil continuum breaks up in the bearing chamber compartment but it is not quantitatively clear how and what parameters affect these. Previous simulation attempt of bearing chamber, also, have been limited by the boundary conditions for the oil. This work presents a computational fluid dynamics (CFD) transient simulation of flow in the bearing sector in an attempt create boundary conditions for such models. The current results show that the oil emerges in the form of droplets into the bearing chamber compartment with speed of the order of 10% of the shaft rotation.

scholarly journals Modeling and Dynamic Analysis of Spherical Roller Bearing with Localized Defects: Analytical Formulation to Calculate Defect Depth and Stiffness

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Behnam Ghalamchi ◽  
Jussi Sopanen ◽  
Aki Mikkola
Keyword(s):  
Dynamic Model ◽  
Contact Stiffness ◽  
Roller Bearing ◽  
Measurement Data ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Radial Clearance ◽  
Outer Race ◽  
Rolling Elements ◽  
Localized Defects

Since spherical roller bearings can carry high load in both axial and radial direction, they are increasingly used in industrial machineries and it is becoming important to understand the dynamic behavior of SRBs, especially when they are affected by internal imperfections. This paper introduces a dynamic model for an SRB that includes an inner and outer race surface defect. The proposed model shows the behavior of the bearing as a function of defect location and size. The new dynamic model describes the contact forces between bearing rolling elements and race surfaces as nonlinear Hertzian contact deformations, taking radial clearance into account. Two defect cases were simulated: an elliptical surface on the inner and outer races. In elliptical surface concavity, it is assumed that roller-to-race-surface contact is continuous as each roller passes over the defect. Contact stiffness in the defect area varies as a function of the defect contact geometry. Compared to measurement data, the results obtained using the simulation are highly accurate.

Influence of Geometrical Features of Material Defects on the Identification Level by the Eddy Current Method

2015 ◽  
Vol 237 ◽  
pp. 136-141
Author(s):  
Wojciech Jóźwik ◽  
Tomasz Samborski
Keyword(s):  
Eddy Current ◽  
Surface Defects ◽  
Roller Bearing ◽  
Current Method ◽  
Eddy Current Method ◽  
Cross Sectional ◽  
Tapered Roller Bearing ◽  
Geometrical Features ◽  
Inner Surface ◽  
The Face

The article presents the results of the influence of geometrical features of defects in materials on the level of identification by the eddy current method. The study involved the inner ring of the tapered roller bearing. Four test defects, located at a constant distance from the inner surface, and a subsurface marker defect were performed in the treadmill of the tested ring. The test defects had a constant cross-sectional area in a perpendicular direction to the surface of the eddy current head. The geometrical features of each defect were the following: shape, the perimeter of the defect projected onto the surface of the ring, and the width and height of the defect projected on the face of the measuring head. The study involved an inner surface (subsurface defect detection) and external surface (the study of surface defects). It has been shown that the shape of the defect affects the level of detection using the eddy current method.

Analysis of radial roller bearing rating life in complex loading conditions

2021 ◽  
pp. 1-27
Author(s):  
Vladimir Ivannikov ◽  
Mikhail Leontiev ◽  
Sergey Degtyarev ◽  
Valeriy Popov
Keyword(s):  
High Performance ◽  
Roller Bearing ◽  
Complex Loading ◽  
Contact Forces ◽  
Loading Conditions ◽  
Jet Engines ◽  
Inertia Effects ◽  
Internal Contact ◽  
Rolling Elements ◽  
Life Analysis

Abstract An approach for accurate life analysis of radial roller bearings in complex loading conditions is presented. It employs ISO~16281 and accounts not only for external radial loads applied to the inner ring, but also for (i) internal bearing clearance, (ii) flexibility of the bearing rings, (iii) rings out-of-roundness, (iv) inertia effects, (v) rolling elements profile and (vi) rings misalignment. In the last decades these factors have been becoming more and more important for modern high-performance jet engines, whose shafts are commonly hollow and the housing and the rings thicknesses may be of comparable magnitudes. To obtain the distribution of internal contact forces, an advanced static model of a bearing with deformable, potentially misaligned, rings is developed. The bending deformations of the rings are reproduced superimposing deformed shapes from each of the arising internal contact force applied individually. Bearing rollers are allowed to have non-cylindrical profile, its geometry is approximated by means of slices each having constant diameter. A robust numerical scheme for solving the resultant set of equations with the aid of the barrier functions method is constructed. To increase even further the accuracy of rating life analysis, distributions of the contact stresses between the roller and the ring surfaces, obtained by solving numerically the problem of non-Hertzian interaction, are added to computations. A numerical benchmark test is presented to demonstrate the applicability of the developed approach. It shows how the aforementioned factors influence the bearing contact forces and its rating life.

Paper 14: Measurement of Film Thickness in a Taper Roller Bearing

1969 ◽  
Vol 184 (12) ◽  
pp. 103-110
Author(s):  
D. A. Jones ◽  
A. B. Crease
Keyword(s):  
Film Thickness ◽  
Surface Finish ◽  
Thrust Bearing ◽  
Roller Bearing ◽  
Rolling Contacts ◽  
Rolling Elements ◽  
Elastohydrodynamic Film Thickness ◽  
Taper Roller Bearing

This paper describes an attempt to measure the elastohydrodynamic film thickness generated within the rolling contacts of a conventional taper roller thrust bearing. The technique used is simple and unambiguous and should be capable of application irrespective of the surface finish or geometry of the rolling elements.

Theoretical Study on the Influence of Planet Gear Rim Thickness and Bearing Clearance on Calculated Bearing Life

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Andreas Fingerle ◽  
Jonas Hochrein ◽  
Michael Otto ◽  
Karsten Stahl
Keyword(s):  
High Efficiency ◽  
Roller Bearing ◽  
The Body ◽  
Fem Model ◽  
Bearing Life ◽  
Bearing Load ◽  
Rolling Elements ◽  
Planet Gear ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Abstract Planetary gearboxes are becoming more popular due to their high-power density and potentially high efficiency. When the planet bearings are internally mounted, the body of the planet gear has to be hollow. The demand for large outer diameters due to high-load requirements might result in a small planet rim thickness. Depending on the rim thickness, its rigidity may become very low. Due to the low stiffness and the special load conditions caused by the double meshing, the deformation of the planet and its bearings are unique. In this paper, the influence of rim thickness on bearing load and lifetime is examined. The analysis is performed with a finite element method (FEM) model of a planet rim with a built-in cylindrical roller bearing. With the resulting planet deformation from the FEM calculation, the load distribution on the rolling elements in the bearing and the bearing lifetime according to ISO/TS 16281:2008 has been evaluated.

Theoretical Study on the Influence of Planet Gear Rim Thickness and Bearing Clearance on Calculated Bearing Life

2019 ◽  
Author(s):  
Andreas Fingerle ◽  
Jonas Hochrein ◽  
Michael Otto ◽  
Karsten Stahl
Keyword(s):  
High Efficiency ◽  
Roller Bearing ◽  
The Body ◽  
Fem Model ◽  
Bearing Life ◽  
Bearing Load ◽  
Rolling Elements ◽  
Planet Gear ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

Abstract Planetary gearboxes are becoming more popular due to their high power density and potentially high efficiency. When the planet bearings are internally mounted, the body of the planet gear has to be hollow. The demand for large outer diameters due to high load requirements might result in a small planet rim thickness. Depending on the rim thickness, its rigidity may become very low. Due to the low stiffness and the special load conditions caused by the double meshing, the deformation of the planet and its bearings are unique. In this paper, the influence of rim thickness on bearing load and lifetime are examined. The analysis is performed with an FEM model of a planet rim with a built-in cylindrical roller bearing. With the resulting planet deformation from the FEM calculation, the load distribution on the rolling elements in the bearing and the bearing lifetime according to ISO/TS 16281:2008 have been evaluated.

Design Optimization of Snap-Fit Integral Parts by FEA and Statistical Analysis

2006 ◽  
Author(s):  
L. Goteti ◽  
J. Choi ◽  
J. Park
Keyword(s):  
Three Dimensional ◽  
Statistical Technique ◽  
Considerable Effect ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Geometrical Features ◽  
Length Width ◽  
Integral Attachment ◽  
Plastic Parts

Snap-fit integral attachments are used widely for joining plastic parts. The proliferated use of integral attachment in the form of snap-fit features in designs is due to the ability to mould such parts of great complexity at little cost. The exceptional diversity of part geometry and integral snap-fit features has made it seem that design possibilities may be unlimited. Thus, attempts at optimization might be intractable. A design of experiments (DOE) approach coupled with three-dimensional, geometrical non-linear finite element analysis (FEA) was used to calculate the insertion and retention responses on such parts for various geometrical parameters like length, width and angles. A statistical technique was employed to formulate empirical relationships among the geometrical dimensions, to investigate the effect of these parameters on the design as well as to obtain optimal insertion and retention forces or strains. Design equations obtained from this methodology were verified within the DOE domain and it was observed that the predicted responses were ranged within 30% of the FEA results. During this investigation, it was observed that geometrical features of a block, which exert force on the snap-fit features, have a considerable effect on the results. Therefore, the effects of the block parameters on the various responses were also studied. An attempt was also made to understand the effect of the block parameters such as corner radius and thickness on the design formula, which depicts the geometrical parameters of the snap-fit part as a function of insertion and retention forces. It is expected that the results help to find optimal design parameters in order to enhance the performance of such snap-fit features.

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