A New Rolling Contact Surface and “No Run-In” Performance Bearings

1995 ◽  
Vol 117 (1) ◽  
pp. 166-170 ◽  
Author(s):  
Rao S. Zhou ◽  
Fukuo Hashimoto
Keyword(s):  
Plastic Deformation ◽  
Rolling Contact ◽  
Rolling Element Bearing ◽  
Test Results ◽  
Deformation Properties ◽  
Rolling Element ◽  
Rolling Elements ◽  
Element Bearing ◽  
Contact Surfaces ◽  
Running Torque

Plasticity indexes are usually used to describe the elastic-plastic deformation properties of a rough surface. The contact surfaces of any new rolling element bearing always change during the bearing run-in period until arriving upon a relatively stable surface texture. In this paper, a new random isotropic surface with very low plasticity index is proposed and created for the surfaces of rolling elements bearings. From both the calculated surface parameters and the run-in torque test results, the special rolling contact surfaces demonstrated “No Run-In” characteristics. Lower running torque is obtained from bearing tests and longer fatigue life is also expected by the subsurface stress analysis.

Rolling Element Bearing Non-Linearity Effects

2000 ◽  
Author(s):  
N. S. Feng ◽  
E. J. Hahn
Keyword(s):  
Equations Of Motion ◽  
Rolling Element Bearing ◽  
Radial Clearance ◽  
Rotor Systems ◽  
Bearing Life ◽  
Rolling Element ◽  
Bearing Load ◽  
Rolling Elements ◽  
Element Bearing ◽  
Negative Clearance

Non-linearity effects in rolling element bearings arise from two sources, viz. the Hertzian force deformation relationship and the presence of clearance between the rolling elements and the bearing races. Assuming that centrifugal effects may be neglected and that the presence of axial preload is appropriately reflected in a corresponding change in the radial clearance, this paper analyses a simple test rig to illustrate that non-linear phenomena such as synchronous multistable and nonsynchronous motions are possible in simple rigid and flexible rotor systems subjected to unbalance excitation. The equations of motion of the rotor bearing system were solved by transient analysis using fourth order Runge Kutta. Of particular interest is the effect of clearance, governed in practice by bearing specification and the amount of preload, on the vibration behaviour of rotors supported by ball bearings and on the bearing load. It is shown that in the presence of positive clearance, there exists an unbalance excitation range during which the bearing is momentarily not transmitting force owing to contact loss, resulting in rolling element raceway impact with potentially relatively high bearing forces; and indicating that for long bearing life, operation with positive clearance should be avoided in the presence of such unbalance loading. Once the unbalance excitation is high enough to avoid such contact loss, it is the bearings with zero or negative clearance which produce maximum bearing forces.

Development of Compact Damper Bearing

2005 ◽  
Author(s):  
Hiroshi Kanki ◽  
Yosichika Sato ◽  
Takayuki Ueshima
Keyword(s):  
Rotating Machinery ◽  
Rolling Element Bearing ◽  
Squeeze Film ◽  
Test Results ◽  
Thin Ring ◽  
Compact Size ◽  
Standard Design ◽  
Rolling Element ◽  
Aero Engine ◽  
Element Bearing

The squeeze film damper bearings have been successfully applied for important rotating machinery such as aero engine, high pressure centrifugal compressors[1] and steam turbine[2]. This paper proposes the expansion of application of the damper bearing for small and medium sized rotating machinery. The new damper has a compact size that enable standard design combined with rolling element bearing. A new design of the damper is presented. The new design consists of thin ring and special patterned wire cut grooves. The design analysis and experimental study are presented. The dynamic tests were carried out for this model damper, one is no side seal and the other is with side seals in both ends. Test results showed the sufficient damping effect for actual applications.

Diagnosis of Rolling-Element Bearings Failure by Localized Electrical Current Between Track Surfaces of Races and Rolling-Elements

2002 ◽  
Vol 124 (3) ◽  
pp. 468-473 ◽  
Author(s):  
Har Prashad
Keyword(s):  
Theoretical Model ◽  
Electrical Current ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Bearing Failure ◽  
Cause Analysis ◽  
Rolling Element ◽  
Rolling Elements ◽  
Dimensional Parameters ◽  
Element Bearing

The diagnosis and cause analysis of rolling-element bearing failure have been well studied and established in literature. Failure of bearings due to unforeseen causes were reported as: puncturing of bearings insulation; grease deterioration; grease pipe contacting the motor base frame; unshielded instrumentation cable; the bearing operating under the influence of magnetic flux, etc. These causes lead to the passage of electric current through the bearings of motors and alternators and deteriorate them in due course. But, bearing failure due to localized electrical current between track surfaces of races and rolling-elements has not been hitherto diagnosed and analyzed. This paper reports the cause of generation of localized current in presence of shaft voltage. Also, it brings out the developed theoretical model to determine the value of localized current density depending on dimensional parameters, shaft voltage, contact resistance, frequency of rotation of shaft and rolling-elements of a bearing. Furthermore, failure caused by flow of localized current has been experimentally investigated.

Transient Rotordynamic Modeling of Rolling Element Bearing Systems

2001 ◽  
Author(s):  
A. Liew ◽  
N. S. Feng ◽  
E. J. Hahn
Keyword(s):  
Rolling Element Bearing ◽  
Hertzian Contact ◽  
Centrifugal Load ◽  
Linear Behavior ◽  
Deep Groove ◽  
Rolling Element ◽  
Rolling Elements ◽  
Load Effects ◽  
Element Bearing ◽  
Bearing Preload

Non-linearity effects in rolling element bearings may arise from the Hertzian contact force deformation relationship, the presence of clearance between the rolling elements and the bearing races, and the bearing to housing clearance. Assuming zero bearing to housing clearance and ignoring rolling element centrifugal load effects, it has been shown in earlier work that Rotor Bearing Systems (RBSs) with deep groove ball bearings can give rise to non-linear behavior such as chaotic motion and jump. This paper extends the bearing model to include rolling element centrifugal load, angular contacts and axial dynamics. The effect of more sophisticated bearing models is illustrated in both a rigidly supported rigid RBS and a flexibly supported flexible RBS, the latter being a model of a test rig designed to simulate an aircraft mounted accessory drive unit. Results are presented on the effect of bearing preload on the unbalance response up to a speed of 18,000 rpm.

Spalling Size Evaluation of Rolling Element Bearing Using Acoustic Emission

2013 ◽  
Vol 569-570 ◽  
pp. 497-504 ◽  
Author(s):  
An Bo Ming ◽  
Zhao Ye Qin ◽  
Wei Zhang ◽  
Fu Lei Chu
Keyword(s):  
Acoustic Emission ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Outer Race ◽  
Cepstrum Analysis ◽  
Rolling Element ◽  
Rolling Elements ◽  
Element Bearing ◽  
Envelope Spectrum ◽  
Size Evaluation

Spalling of the races or rolling elements is one of the most common faults in rolling element bearings. Exact estimation of the spall size is helpful to the life prediction for rolling element bearings. In this paper, the dual-impulsive phenomenon in the response of a spalled rolling element bearing is investigated experimentally, where the acoustic emission signals are utilized. A new method is proposed to estimate the spall size by extracting the envelope of harmonics of the ball passing frequency on the outer race from the squared envelope spectrum. Compared with the cepstrum analysis, the proposed procedure shows more powerful anti-noise ability in the fault size evaluation.

Rolling-Element Bearing Heat Transfer—Part III: Experimental Validation

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
William M. Hannon ◽  
Todd A. Barr ◽  
Shawn T. Froelich
Keyword(s):  
Heat Transfer ◽  
Experimental Validation ◽  
Rolling Element Bearing ◽  
Transfer Model ◽  
Test Results ◽  
Model Framework ◽  
Rolling Element ◽  
Heat Partitioning ◽  
Scale Test ◽  
Element Bearing

This paper concludes a series of papers outlining a new rolling-element bearing heat transfer model. Part I provided the model framework, Part II presented the partial differential equation (PDE) solutions, and Part III, this paper, presents full-scale test results for ball, cylindrical, spherical, and tapered rolling-element bearings. The results validate the heat partitioning equation and the predicted solid temperatures for circulating oil lubrication. In addition, sump lubrication was studied using an acrylic assembly. The results quantify what fraction of the bearing periphery is cooled by oil, as well as the flow of oil through a bearing. Finally, substantiation of the modeling assumptions is discussed.

Load Distribution in a Rolling Element Bearing under Dynamic Radial Load

2014 ◽  
Vol 592-594 ◽  
pp. 1099-1103 ◽  
Author(s):  
T. Govardhan ◽  
Achintya Choudhury ◽  
Deepak Paliwal
Keyword(s):  
Dynamic Loading ◽  
Load Distribution ◽  
Rolling Element Bearing ◽  
Radial Clearance ◽  
Random Loading ◽  
Rolling Element ◽  
Rolling Elements ◽  
Mean And Variance ◽  
Element Bearing ◽  
The Difference

External load in a bearing is transferred from one race to another race through the rolling elements. In the present work, an investigation has been made to estimate the load on a rolling element in a bearing subjected to dynamic loading. The dynamic loading, in the present study, included harmonic and periodic loadings which are deterministic functions of time. The roller load is also investigated under random loading with known statistical values of mean and variance. Numerical values have been obtained for NJ204 bearing with known radial clearance. These results show the variation in the spectra obtained for different nature of external loadings. These results can be expected to satisfy the difference in theoretical and experimental spectra obtained by earlier researchers.

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