Information Entropy of Rolling Bearing Friction Torque as Data Series

2010 ◽  
Vol 44-47 ◽  
pp. 1115-1119 ◽  
Author(s):  
Xin Tao Xia ◽  
Long Chen ◽  
Fan Nian Meng
Keyword(s):  
Experimental Investigation ◽  
Information Entropy ◽  
Rotational Speed ◽  
Dynamic Performance ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Data Series ◽  
Entropy Theory ◽  
Rolling Bearings ◽  
Bearing Friction

The information entropy theory is applied to evaluate the uncertainty of the rolling bearing friction torque. The data series are obtained via the experimental investigation on the friction torque of the rolling bearings under the condition of different rotational speeds. And the result shows that the information entropy of the friction torque increases with the rotational speed of the rolling bearing, revealing the new dynamic performance of the rolling bearing friction torque as a data series.

Uncertainty of Rolling Bearing Friction Torque as Data Series Using Grey Bootstrap Method

2010 ◽  
Vol 44-47 ◽  
pp. 1125-1129
Author(s):  
Xin Tao Xia ◽  
Long Chen ◽  
Fan Nian Meng
Keyword(s):  
System Theory ◽  
Experimental Investigation ◽  
Bootstrap Method ◽  
Dynamic Performance ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Data Series ◽  
Rolling Bearings ◽  
The Mean ◽  
Bearing Friction

Based on the information poor system theory, the grey bootstrap method is employed to estimate the uncertainty of the rolling bearing friction torque. The data series are obtained via the experimental investigation of the friction torque of the rolling bearings under the condition of different rotational speeds. And the results show that the mean of the dynamic fluctuant range (MDFR) of the friction torque increases with the rotational speed of the rolling bearing, revealing the new dynamic performance of the rolling bearing friction torque as a data series.

Chaotic Characteristic and Nonlinear Dynamic Performance of Rolling Bearing Friction Torque

2010 ◽  
Vol 26-28 ◽  
pp. 88-92 ◽  
Author(s):  
Xin Tao Xia ◽  
Tao Mei Lv ◽  
Fan Nian Meng
Keyword(s):  
Time Series ◽  
Nonlinear Dynamic ◽  
Dynamic Performance ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Box Dimension ◽  
Rolling Bearings ◽  
Chaotic Characteristic ◽  
Chaotic Theory ◽  
Bearing Friction

Based on the chaotic theory, the methods of the Lyapunov exponent and the box dimension were applied to evaluate the chaotic characteristic and the nonlinear dynamic performance of the rolling bearing friction torque. The time series were obtained via the experimental investigation on the friction torque of the rolling bearings under the condition of different rotational speeds. It is found that the rolling bearing friction torque is of a chaotic system because the maximum of Lyapunov exponents of its time series is greater than zero according to the chaotic theory. And the result shows that the mean of the box dimension of the friction torque increases with the rotational speed of the rolling bearing, revealing the new dynamic performance of the rolling bearing friction torque as a time series.

Chaos Prediction of Rolling Bearing Friction Torque

2010 ◽  
Vol 26-28 ◽  
pp. 190-193 ◽  
Author(s):  
Xin Tao Xia ◽  
Tao Mei Lv
Keyword(s):  
Time Series ◽  
Experimental Investigation ◽  
Chaos Theory ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Local Region ◽  
Space Applications ◽  
Region Method ◽  
Weight One ◽  
Bearing Friction

Based on the chaos theory, the adding-weight one-rank local-region method was applied to predict the time series of the rolling bearing friction torque. The experimental investigation on the rolling bearing for space applications shows that the method is able to predict effectively the rolling bearing friction torque, only with very small predicted error.

Rolling Bearing Parametric Excitation of a Jeffcott Rotor System

2020 ◽  
Author(s):  
Ghasem Ghannad Tehrani ◽  
Chiara Gastaldi ◽  
Teresa Maria Berruti
Keyword(s):  
Parametric Excitation ◽  
Rotational Speed ◽  
Input Parameter ◽  
Equations Of Motion ◽  
Harmonic Balance Method ◽  
Rolling Bearing ◽  
Mean Value ◽  
Hertzian Contact ◽  
Rolling Bearings ◽  
Jeffcott Rotor

Abstract Rolling bearings are still widely used in aeroengines. Whenever rotors are modeled, rolling bearing components are typically modeled using springs. In simpler models, this spring is considered to have a constant mean value. However, the rolling bearing stiffness changes with time due to the positions of the balls with respect to the load on the bearing, thus giving rise to an internal excitation known as Parametric Excitation. Due to this parametric excitation, the rotor-bearings system may become unstable for specific combinations of boundary conditions (e.g. rotational speed) and system characteristics (rotor flexibility etc.). Being able to identify these instability regions at a glance is an important tool for the designer, as it allows to discard since the early design stages those configurations which may lead to catastrophic failures. In this paper, a Jeffcott rotor supported and excited by such rolling bearings is used as a demonstrator. In the first step, the expression for the time–varying stiffness of the bearings is analytically derived by applying the Hertzian Contact Theory. Then, the equations of motion of the complete system are provided. In this study, the Harmonic Balance Method (HBM) is used to as an approximate procedure to draw a stability map, thus dividing the input parameter space, i.e. rotational speed and rotor physical characteristics, into stable and unstable regions.

scholarly journals A new model for predicting the mechanical efficiency of ball screws based on the empirical equations for the friction torque of rolling bearings

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401880017 ◽  
Author(s):  
Chang-Guang Zhou ◽  
Hu-Tian Feng ◽  
Yi Ou
Keyword(s):  
Rotational Speed ◽  
Axial Load ◽  
High Speed ◽  
Mechanical Efficiency ◽  
Friction Torque ◽  
Numerical Control ◽  
Measuring System ◽  
Empirical Equations ◽  
Rolling Bearings ◽  
New Model

Based on the empirical equations for the friction torque of rolling bearings, this article proposes a new model for predicting the friction torque and mechanical efficiency of ball screws. Meanwhile, a novel measuring system is constructed to obtain the mechanical efficiency of ball screws, where both the axial load and rotational speed are stable and adjustable. The experimental results at a rotational speed of 1000 r/min agree well with the theoretical values calculated by the present method, which show that the mechanical efficiency of ball screws increases with increasing axial load. Moreover, the model built in this article is more applicable to a relatively high-speed condition. The new model can be easily used to obtain the friction torque and mechanical efficiency for ball screws, which is essential for improving the performance of ball screws and the computer numerical control machine tools.

Poor Information Analysis of Rolling Bearing Friction Torque Characteristic Parameter Based on Phase Space

2011 ◽  
Vol 382 ◽  
pp. 167-171
Author(s):  
Lei Lei Gao ◽  
Xin Tao Xia
Keyword(s):  
Time Series ◽  
Phase Space ◽  
Characteristic Parameter ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Point Estimation ◽  
Experimental Result ◽  
Bayesian Probability ◽  
Characteristic Parameters ◽  
Bearing Friction

The friction torque of rolling bearings belongs to an information poor system with unknown probability distributions and trends. This counteracts dynamical assessment for the characteristics of the rolling bearing friction torque as a time series. For this reason, the chaos theory is employed to recover the original dynamic characteristics of a friction torque time series by means of the phase space reconstruction theory. The dynamical Bayesian probability density function of the characteristic parameters of the friction torque is constructed by the information poor theory based on the phase space. The method for point estimation, interval estimation, and trend estimation of the characteristic parameters is proposed in this paper. The investigation shows that the error between the calculated result and the experimental result is very small.

Gray Chaos Evaluation Model for Prediction of Rolling Bearing Friction Torque

2010 ◽  
Vol 38 (3) ◽  
pp. 102623 ◽  
Author(s):  
M. R. Mitchell ◽  
R. E. Link ◽  
Xia Xintao ◽  
Lv Taomei ◽  
Meng Fannian
Keyword(s):  
Evaluation Model ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Bearing Friction

GreenBearings – Friction Behaviour of DLC-Coated Dry Running Deep Groove Ball Bearings

2015 ◽  
Vol 805 ◽  
pp. 147-153 ◽  
Author(s):  
Julia Kröner ◽  
Stephan Tremmel ◽  
Serge Kursawe ◽  
Yashar Musayev ◽  
Tim Hosenfeldt ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Energy Savings ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Wear Behaviour ◽  
Ball Bearings ◽  
Rolling Bearings ◽  
Pumping Stations ◽  
Deep Groove ◽  
First Results

Due to the use of rolling bearings instead of plain bearings friction and wear are drastically reduced in all kind of machines. However, despite the high technical standard of modern rolling bearings there is still a significant potential for optimization. Preliminary Studies show a reduction of the friction torque of up to 44 % compared to conventional rolling bearings because of the use of tribological coatings in certain applications. Based on the millionfold usage of rolling bearings in all industrial fields the reduced lost energy adds up to a remarkable potential for energy savings. If friction and wear are lowered sufficiently, the use of conventional lubricants based on mineral oil can be successively decreased or even completely avoided. In the latter case, the socalled dry running of the rolling bearing, the energy consumption of machines and systems can additionally be reduced significantly. For example, pumping stations or compressed air units, which would be necessary for transporting or spraying the lubricants, can then be saved.This paper presents first results of DLC-coated deep groove ball bearings, which are tested in a four-bearing-test-rig under purely radial load with respect to their friction and wear behaviour.

Dynamic Prediction Model for Rolling Bearing Friction Torque Using Grey Bootstrap Fusion Method and Chaos Theory

2012 ◽  
Vol 443-444 ◽  
pp. 87-96 ◽  
Author(s):  
Xin Tao Xia ◽  
Tao Mei Lv
Keyword(s):  
Probability Distributions ◽  
Rolling Bearing ◽  
Friction Torque ◽  
Local Region ◽  
Fusion Method ◽  
Dynamic Prediction ◽  
Region Method ◽  
True Value ◽  
Weight One ◽  
Bearing Friction

Synthesizing the grey bootstrap fusion method and the five chaos forecasting methods (viz., the adding-weight zero-rank local-region method, the one-rank local-region method, the adding-weight one-rank local-region method, the improved adding-weight one-rank local-region method, and the maximum Lyapunov exponent method), a dynamic prediction model is proposed to calculate the predicted true value and the predicted interval of a chaotic time series under the condition of unknown probability distributions and trends. At the same time, the five forecasting values are acquired with the help of the five chaos forecasting methods, respectively, and the five forecasting values are fused to deduce the predicted true value and the predicted interval by means of the grey bootstrap fusion method. As time goes on, a series of the predicted true value and the predicted interval is obtained dynamically. Experimental investigation of the rolling bearing friction torque shows that using the grey bootstrap fusion method, the predicted true value and the measured values have an identical trend only with a small error, the predicted interval is acquired along with a high reliability, and the dynamic prediction of the rolling bearing friction torque as a chaotic time series is made without any prior knowledge of probability distributions and trends.

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