The impact of vibration response due to rolling bearing components waviness on the performance of grinding machine spindle system

2019 ◽  
Vol 233 (3) ◽  
pp. 747-762 ◽  
Author(s):  
Mohammed Alfares ◽  
Ghanim Al-Daihani ◽  
Jasim Baroon
Keyword(s):  
Degrees Of Freedom ◽  
Nonlinear Dynamical System ◽  
Vibration Response ◽  
Spindle System ◽  
Outer Race ◽  
Ball Surface ◽  
Machine Spindle ◽  
Grinding Machine ◽  
The Impact ◽  
Inner Race

In this research, an analytical model based on a five-degrees-of-freedom nonlinear dynamical system was utilized to investigate the impact of vibration response due to inner race, outer race, and ball bearing waviness on the performance of grinding machine spindle system supported by two angular ball bearings. The waviness of rolling elements is modeled as a sinusoidal function is incorporated along the inner or outer races of bearing and ball surface. The elastic deflection and nonlinear contact force are calculated based on Hertzian contact model, while the shaft has five-degrees-of-freedom motions, three translational and two angular motions. The five–degrees-of-freedom nonlinear governing equations of the spindle system were developed taking into consideration the effect of outer race, inner race, and ball surface waviness, which are included in the kinematic constraints and force equilibrium equations of a ball. The developed model and its results are validated against results found in literature. Results by this paper indicate that the inner race waviness can significantly distort the tolerance and machining quality of grinding spindle-bearing systems more than does waviness in the outer race and ball elements. This is because the inner race waviness generates more complicated vibrations than the outer race and ball waviness. The most severe vibrations caused by the inner race waviness were found to occur when the waviness was of the order that is equal to multiple of number of balls in a bearing set plus or minus one ([Formula: see text]).

Nonlinear Behaviors of the Machine-Tool Spindle System Supported by Ball Bearings With Clearance

2008 ◽  
Author(s):  
S.-H. Gao ◽  
X.-H. Long ◽  
H.-G. Li ◽  
G. Meng
Keyword(s):  
Machine Tool ◽  
Natural Frequency ◽  
Excitation Frequency ◽  
Ball Bearings ◽  
Spindle System ◽  
Nonlinear Responses ◽  
Machine Tool Spindle ◽  
Loss Of Contact ◽  
The Impact ◽  
Inner Race

In this effort, the nonlinear dynamics of a machine-tool spindle system supported by ball bearings is investigated. Considering the loss of contact between the inner race and ball in the ball bearing, the system is described by a set of second order nonlinear differential equations with piecewise stiffness and damping. The nonlinear responses of the system exhibit the softening behavior due to the loss of contact. As the initial preload is applied to the spindle system and the balls are fully contacting with the inner race of the bearing, the nonlinear responses of the system switche to the hardening behavior. Due to the 3/2 nonlinearity, resonance are found when the excitation frequency is close to one-third of the first natural frequency, one-half of the first nature frequency, two-third of the first natural frequency, and the first natural frequency. The route of the period-doubling bifurcation to chaos and the tori doubling process to chaos which usually occurs in the impact system are also observed in this spindle-bearing system.

Research on the Dynamic Characteristics of NC Boring Machine Spindle System Based on Finite Element Analysis

2013 ◽  
Vol 819 ◽  
pp. 71-75
Author(s):  
Feng Jiao ◽  
Guang Ming Sun ◽  
Jian Hui Liu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Characteristics ◽  
Hydrodynamic Lubrication ◽  
Dynamic Stiffness ◽  
Element Analysis ◽  
Spindle System ◽  
Machine Performance ◽  
Machine Spindle ◽  
The Impact

In this paper, elastic hydrodynamic lubrication theory was introduced into bearing dynamic stiffness calculation process to take into account the impact of the oil film on the rolling stiffness. Dynamic characteristics of NC boring machine spindle system dedicated to the manufacturing of bearing retainer were studied based on finite element analysis software. The rationality of the structural design of spindle was verified in the paper. The research provided a theoretical basis for the improvement of machine performance and dynamic design of NC boring machine spindle.

Computer aided optimum design of machine tool spindle systems with hydrostatic bearings

1997 ◽  
Vol 211 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Montusiewicz ◽  
A Osyczka
Keyword(s):  
Optimum Design ◽  
Optimization Strategy ◽  
Spindle System ◽  
System A ◽  
Hydrostatic Bearings ◽  
Computer Aided ◽  
Lathe Machine ◽  
Machine Spindle ◽  
Design Software ◽  
Grinding Machine

A general model of the spindle system with hydrostatic bearings is presented. In this model the whole system is divided into subsystems. Each of these subsystems is modelled in order to obtain an optimization considering the global criteria of the system. A four-stage multicriterion optimization strategy is applied to solve the problem. On the basis of this strategy, which has a heuristic character, a computer aided optimum design software package for spindle systems for grinding and lathe machine tools is developed. The software is supported by computer graphics. An example of designing a grinding machine spindle system is given.

A Theoretical Model to Predict the Vibration Response of Rolling Bearings in a Rotor Bearing System to Distributed Defects Under Radial Load

1999 ◽  
Vol 122 (3) ◽  
pp. 609-615 ◽  
Author(s):  
N. Tandon ◽  
A. Choudhury
Keyword(s):  
Theoretical Model ◽  
Vibration Response ◽  
Radial Load ◽  
Outer Race ◽  
Rolling Element ◽  
Spectral Components ◽  
Rotor Bearing ◽  
Defect Frequency ◽  
Inner Race ◽  
Bearing System

A theoretical model to predict the vibration response of rolling element bearing in a rotor bearing system to distributed defects under radial load has been developed. The rotor bearing system has been considered as a three degrees of freedom model. The distributed defects considered are, the waviness of outer and inner races, and off size rolling element. The model predicts discrete spectrum with specific frequency components for each order of waviness. For outer race waviness, the spectrum has components at outer race defect frequency and its harmonics. In the case of inner race waviness, the waviness orders equal to number of rolling elements and its multiples give rise to spectral components at inner race defect frequency and its multiples. Other orders of waviness generate sidebands at multiples of shaft frequency about these peaks. The model predicts the amplitudes of the spectral components due to outer race waviness to be much higher as compared to those due to inner race waviness. In the case of an off-size rolling element, the model predicts discrete spectra having significant components at multiples of cage frequency. [S0742-4787(00)00603-2]

Vibration Modeling of a Rigid Rotor Supported on the Lubricated Angular Contact Ball Bearings Considering Six Degrees of Freedom and Waviness on Balls and Races

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
C. K. Babu ◽  
N. Tandon ◽  
R. K. Pandey
Keyword(s):  
Degrees Of Freedom ◽  
High Amplitude ◽  
Ball Bearings ◽  
Rigid Rotor ◽  
Outer Race ◽  
Six Degrees Of Freedom ◽  
Proposed Model ◽  
Sinusoidal Functions ◽  
Rotor Bearings ◽  
Inner Race

Nonlinear vibration analysis of angular contact ball bearings supporting a rigid rotor is presented herein considering the frictional moments (load dependent and load independent components of frictional moments) in the bearings. Six degrees of freedom (DOF) of rigid rotor is considered in the dynamic modeling of the rotor-bearings system. Moreover, waviness on surfaces of inner race, outer race, and ball are considered in the model by representing it as sinusoidal functions with waviness orders of 6, 15, and 25. Two amplitudes of waviness, 0.05 and 0.2 μm, are considered in the investigation looking for the practical aspects. The proposed model is validated with the experimental results by performing the experiments. Moreover, the present model has also been validated with published results of researchers by incorporating needful changes in the DOF in the proposed model. Based on the computed results, it is observed that load dependent frictional moment (LDFM) significantly enhances the amplitudes of vibrations in comparison to load independent frictional moment (LIFM) irrespective to values of waviness amplitude and waviness order. The influence of inner race waviness is relatively more on the vibrations in comparison to waviness of outer race and ball. Moreover, vibrations of system enhance considerably at high amplitude of waviness, increase in the order of waviness, and at elevated operating parameters.

scholarly journals Effect of Various Defects in Roller Bearings and Ball Bearings on Vibration

2019 ◽  
Vol 8 (12) ◽  
pp. 5137-5141
Keyword(s):  
Ball Bearing ◽  
Surface Defects ◽  
Roller Bearing ◽  
Vibration Response ◽  
Maintenance Cost ◽  
Artificial Defect ◽  
Outer Race ◽  
Vibration Signature ◽  
Inner Race ◽  
Load Conditions

The bearing is very important segment in any rotating machinery. It is continually running under changing speed and load conditions. Failure of bearing frequently results in extensive mechanical downtime that has monetary outcomes. Timely diagnosis of bearing breakdown is to avoid machines failure, as well as to decrease the maintenance cost of machine. To analyze failure of the bearing artificial defect were created on various elements of the bearing and using vibration signature for monitoring its condition analysis is carried.In this paper the effect of various surface defects on the vibration response of outer race and inner race of the ball bearing and Roller bearing is discussed. Vibration spectrum produced by bearing with defect on inner or outer race under different load conditions is taken and effect of defect size and load on the vibration response has been investigated. Results are presented in time and frequency domain. The results obtained by experimentations are compared with MATLAB results

Study on Thermal Properties of Hybrid Journal Bearing for Super High Speed Grinding Machine

2010 ◽  
Vol 126-128 ◽  
pp. 808-813 ◽  
Author(s):  
Shi Chao Xiu ◽  
Shi Qiang Gao ◽  
Zhi Li Sun
Keyword(s):  
Thermal Properties ◽  
Temperature Rise ◽  
High Speed ◽  
Journal Bearing ◽  
Spindle System ◽  
Key Factor ◽  
High Speed Grinding ◽  
Machine Spindle ◽  
Grinding Machine ◽  
Heat Mechanism

As the high speed bearings, hybrid journal bearings are usually used in high and super high speed grinding machine spindle system. Since the bearing operates under high speed conditions, the excessive temperature rise of bearing is a key factor to lower the accuracy of the spindle system and limit the bearings working speed, so restrict the bearing applications. In this paper, the model of hybrid journal bearing is established to analyze the heat mechanism. In addition, the temperature field distribution for the certain hybrid journal bearing at high speed is studied by ANSYS considering the heat transfer characters between fluid and solid. The experiment of temperature for hybrid journal bearing system in super high speed grinding machine is also performed. The thermal properties and the measure for controlling temperature rise of such bearings are analyzed.

Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Interference ◽  
Degrees Of Freedom ◽  
Building Blocks ◽  
Ferrocene Derivative ◽  
Single Molecule Junctions ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
The Impact ◽  
D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>

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