scholarly journals A Theoretical Model with the Effect of Cracks in the Local Spalling of Full Ceramic Ball Bearings

2019 ◽  
Vol 9 (19) ◽  
pp. 4142 ◽  
Author(s):  
Huaitao Shi ◽  
Zimeng Liu ◽  
Xiaotian Bai ◽  
Yupeng Li ◽  
Yuhou Wu
Keyword(s):  
Theoretical Model ◽  
Theoretical Basis ◽  
Vibration Amplitude ◽  
Strain Energy ◽  
Outer Ring ◽  
Ball Bearings ◽  
State Monitoring ◽  
Ceramic Ball ◽  
Ceramic Bearing ◽  
Bearing Stiffness

For full ceramic ball bearings, cracks occur frequently in the spalling on the rings, which leads to impacts on the bearing dynamic characteristics. In this paper, the spalling is set on the outer ring, and the dynamic model considering the effect of crack is proposed. The crack is considered to be related to the strain energy, and the effect on the stiffness of the outer ring is also analyzed. Results show that the appearance of cracks leads to the reduction of the full ceramic bearing stiffness, and the vibration amplitude of bearing increases. The effect of a crack depends on its size, and the vibration of the bearing with cracks of different widths and depths vary greatly. This study provides theoretical basis for the calculation of full ceramic bearing and is of great significance for the state monitoring and fault diagnosis.

Vibrations of the All-Ceramic Ball Bearing

2002 ◽  
Vol 124 (3) ◽  
pp. 448-460 ◽  
Author(s):  
Hiroyuki Ohta ◽  
Shinya Satake
Keyword(s):  
Natural Vibration ◽  
Ball Bearing ◽  
Axial Direction ◽  
Outer Ring ◽  
Ball Bearings ◽  
Ceramic Ball ◽  
Vibration Spectra ◽  
All Ceramic ◽  
Hybrid Ceramic ◽  
Mass Type

All-ceramic ball bearings with silicone nitride balls and silicone nitride rings were tested and the vibration characteristics were compared with those of hybrid ceramic ball bearings and conventional steel ball bearings. The vibration measurement results showed that the overall vibratory velocity levels of the all-ceramic ball bearings are influenced by rotational velocities, and do not change with axial loads. Under a given axial load and rotational velocity, the overall vibratory velocity level of the all-ceramic ball bearing is the lowest, and the hybrid ball bearing the highest. The frequencies of main peaks in the measured vibration spectra of the all-ceramic ball bearing are higher than the frequencies of the corresponding main peaks for the hybrid ceramic ball bearing and the steel ball bearing. To explain the main peaks, modal analysis was done and the relationship between peak and natural vibration was analyzed. The results of the analyses showed that the main peaks are caused by: (1) the mass-type natural vibration of the outer ring in the vertical direction, (2) the bending natural vibration of the outer ring in the radial direction, (3) the moment of inertia-type natural vibration of the outer ring in the angular direction, (4) the mass-type natural vibration of the outer ring in the axial direction, and (5) the bending natural vibration of the outer ring in the axial direction. We also discuss the generating mechanism of the vibration and present the calculation method of the vibration spectra. As a result, it is clear that the vibration spectra of the all-ceramic ball bearing are determined by the amplitude of the waviness of the raceways and ball surface, the mobility, and the non-linear spring constant associated with the contact between the raceways and balls.

scholarly journals Spalling Localization on the Outer Ring of Hybrid Ceramic Ball Bearings Based on the Sound Signals

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 134621-134634 ◽  
Author(s):  
H. T. Shi ◽  
X. T. Bai ◽  
K. Zhang ◽  
Z. N. Wang ◽  
Z. M. Liu
Keyword(s):  
Outer Ring ◽  
Ball Bearings ◽  
Ceramic Ball ◽  
Hybrid Ceramic

scholarly journals Effect of the Lubrication Parameters on the Ceramic Ball Bearing Vibration in Starved Conditions

2020 ◽  
Vol 10 (4) ◽  
pp. 1237
Author(s):  
Ke Zhang ◽  
Xianchao Wu ◽  
Xiaotian Bai ◽  
Zinan Wang ◽  
Defang Zou ◽  
...  
Keyword(s):  
Ball Bearing ◽  
Peak Frequency ◽  
Ball Bearings ◽  
Nonlinear Dynamic Model ◽  
Ceramic Ball ◽  
Oil Film ◽  
Research Findings ◽  
Bearing Stiffness ◽  
Bearing Vibration ◽  
Starved Lubrication

The thickness of the oil film in ceramic ball bearings varies greatly at starved lubrication conditions, thus leading to non-uniform contact between the balls and raceways in the circumference. The lubrication parameters have a direct impact on the thickness of the oil film and then affect the dynamic characteristics of the ceramic ball bearings. A nonlinear dynamic model of ceramic ball bearing with limited lubrication is presented in this paper, and parametric studies on the effect of lubrication parameters are conducted. In starved conditions, the uneven contact between the ball and ring leads to changes in vibration, and the inner ring vibration is applied to evaluate the degree of starved lubrication. The results show that as the oil quantity increases, the bearing stiffness increases and results in increased peak frequency. As the oil quantity decreases, the thickness of the oil film reduces, resulting in the bearing vibration increase. The research findings provide a theoretical reference for ceramic ball bearing design and have guided significance for improving the service performance of ceramic ball bearings.

scholarly journals Unbalance Response Prediction for Rotors on Ball Bearings Using Speed- and Load-Dependent Nonlinear Bearing Stiffness

2005 ◽  
Vol 2005 (1) ◽  
pp. 53-59 ◽  
Author(s):  
David P. Fleming ◽  
J. V. Poplawski
Keyword(s):  
Response Prediction ◽  
Rolling Element Bearing ◽  
Response Analysis ◽  
Ball Bearings ◽  
Moderate Amount ◽  
Constant Stiffness ◽  
Unbalance Response ◽  
Rolling Element ◽  
Bearing Stiffness ◽  
Element Bearing

Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus, an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work, bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant-stiffness bearings. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.

scholarly journals Fabrication of nanoporous fibers via bubble electrospinning

2014 ◽  
Vol 18 (5) ◽  
pp. 1455-1458 ◽  
Author(s):  
Fu-Juan Liu ◽  
Ji-Huan He ◽  
Rou-Xi Chen ◽  
Lan Xu ◽  
Ping Wang
Keyword(s):  
Theoretical Model ◽  
Theoretical Basis ◽  
Solvent Evaporation ◽  
Direct Approach ◽  
Key Factor ◽  
Controllable Preparation

A direct approach to fabrication of nanoporous fibers via bubble electrospinning is demonstrated. Solvent evaporation is a key factor for nanopore formation, and a theoretical model is established and analyzed. The paper elucidates a theoretical basis for the controllable preparation of nanoporous fibers.

scholarly journals Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)

2010 ◽  
Vol 5 (1) ◽  
pp. 60-70 ◽  
Author(s):  
Masataka Nosaka ◽  
Satoshi Takada ◽  
Makoto Yoshida ◽  
Masataka Kikuchi ◽  
Takayuki Sudo ◽  
...  
Keyword(s):  
Liquid Hydrogen ◽  
Ball Bearings ◽  
Ceramic Ball ◽  
Hybrid Ceramic

Dynamic Measurement of Bearing Radial Clearances

2005 ◽  
Vol 295-296 ◽  
pp. 361-366 ◽  
Author(s):  
Yu Xue Chen ◽  
S.N. Yang
Keyword(s):  
Measurement Accuracy ◽  
Systematic Errors ◽  
Dynamic Measurement ◽  
Outer Ring ◽  
Radial Clearance ◽  
Test Time ◽  
Ball Bearings ◽  
Test Results ◽  
Accuracy Measures

Outer ring tilted or offset axially, caused by improperly fixing relatively to the inner ring, will produce remarkable systematic errors in measured radial clearance of a bearing. Analyzing their effects in detail on the results of measured radial clearances, they are found to be the main sources affecting the measurement accuracy. Measures for removing them are proposed. Based on these, a novel type of instrument for measurement of radial clearances of ball bearings has been developed. It could avoid the two kinds of systematic errors. The measuring principle, structures and working procedures of the instrument are presented. Test results show that the test time is less than 15 seconds per a part and the indication stability is between ±1.0 µm.

Analysis on location of maximum vibration amplitude in panel flutter

2019 ◽  
Vol 234 (2) ◽  
pp. 457-469 ◽  
Author(s):  
Xianzong Meng ◽  
Zhengyin Ye ◽  
Kun Ye ◽  
Cheng Liu
Keyword(s):  
Theoretical Basis ◽  
Vibration Amplitude ◽  
Dynamic Pressure ◽  
Maximum Amplitude ◽  
Displacement Function ◽  
Limit Cycle Oscillation ◽  
Panel Flutter ◽  
Mathematical Basis ◽  
Critical Dynamic ◽  
Cycle Oscillation

When the panel is under limit cycle oscillation, the location of maximum vibration amplitude always locates at 0.75 of panel length under different dynamic pressure. However, this conclusion is drawn from engineer practice without further investigations on its theoretical basis. Thus, the current study focuses on the theoretical and mathematical basis of this problem. The pattern of the location of maximum amplitude is verified at first by using three numerical methods. Then, based on the law of energy conservation, the displacement function of linear panel oscillation is derived for theoretical investigation. The linear panel consists of two structural modes. Theoretical analysis shows that, under critical dynamic pressure, the generalized displacement responses of two structural modes have opposite phase, the same vibration amplitude and the same vibration frequency. As a result, the superposition of displacement function of two structural modes, which is the displacement function of panel, leads to the occurrence of maximum vibration amplitude at 0.7 of panel length. With more structural modes considered, the location of maximum moves to 0.75 of panel length.

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