scholarly journals 5-DOF Dynamic Modeling of Rolling Bearing with Local Defect considering Comprehensive Stiffness under Isothermal Elastohydrodynamic Lubrication

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Pengfei Yan ◽  
Changfeng Yan ◽  
Kai Wang ◽  
Fengtao Wang ◽  
Lixiao Wu
Keyword(s):  
Film Thickness ◽  
Life Prediction ◽  
High Speed ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Radial Clearance ◽  
Local Defect ◽  
Oil Film ◽  
Rolling Element ◽  
Film Stiffness

The sliding of the rolling element in the load zone would cause the bearing’s wear and failure at high speed under elastohydrodynamic lubrication (EHL) condition. Aiming at this phenomenon, considering lubrication oil film, time-varying displacement, radial clearance, and comprehensive stiffness, a five degree-of-freedom (DOF) dynamic model of rolling bearing with local defect is proposed based on isothermal EHL and which is validated by experimental data. The variation of oil film stiffness, comprehensive stiffness, and vibration characteristics of rolling bearing is studied under different speeds and loads. The results show that the lubricating oils with different viscosities have a certain influence on the bearing oil film thickness and comprehensive stiffness. As the load increases, the oil film stiffness and comprehensive stiffness would increase, and the oil film thickness would decrease. And as the tangential speed increases, the oil film stiffness would increase, and the oil film thickness and comprehensive stiffness would decrease. The vibration amplitude of the rolling bearing is enhanced with the increase of the rotation speed and the radial load. This model is helpful for the optimization, the correct use of lubricants, and life prediction of rolling bearing.

Investigation on the skidding dynamic response of rolling bearing with local defect under elastohydrodynamic lubrication

2019 ◽  
Vol 20 (6) ◽  
pp. 615 ◽  
Author(s):  
Jianxiong Kang ◽  
Yanjun Lu ◽  
Yongfang Zhang ◽  
Cheng Liu ◽  
Sha Li ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Interaction Force ◽  
Local Defect ◽  
Proposed Model ◽  
Significant Difference ◽  
Frequency Domains ◽  
Rolling Element ◽  
Time And Frequency Domains

The rolling element skidding may lead to the failure of the rolling bearing. The skidding characteristics can be effectively analyzed by using dynamic response of the rolling bearing. A dynamic model is established to investigate the vibration response of the rolling bearing with local defect on inner/outer race in this paper. In the proposed model, the rolling element skidding, contact stiffness and displacement, the interaction force between ball and race, the interaction force between cage and race, elastohydrodynamic lubrication are taken into consideration. The dynamic responses of the rolling bearing with the rolling element skidding are solved by the proposed model in the time and frequency domains. The effects of defect size, rotational speed, external load, and compound factors on skidding characteristics are investigated. The proposed model is verified by the experiments. The results show that the rolling element skidding leads to the significant difference of dynamic characteristics in the time and frequency domains, which aggravates the failure of the rolling bearings.

Influence of lubrication starvation and surface waviness on the oil film stiffness of elastohydrodynamic lubrication line contact

2016 ◽  
Vol 24 (5) ◽  
pp. 924-936 ◽  
Author(s):  
Yuanyuan Zhang ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Chaosheng Song ◽  
Zufeng Li
Keyword(s):  
Film Thickness ◽  
Contact Stiffness ◽  
Elastohydrodynamic Lubrication ◽  
Force Balance ◽  
Line Contact ◽  
Surface Waviness ◽  
Regular Surface ◽  
Normal Contact ◽  
Oil Film ◽  
Film Stiffness

Stiffness properties of interfacial engineering surfaces are of great importance to the dynamic performance of relevant mechanical systems. Normal contact stiffness and oil film stiffness of line contact problems are studied in this work analytically and numerically. The Hertzian contact theory and the Yang–Sun method are applied to predict the contact stiffness, while the empirical elastohydrodynamic lubrication (EHL) film thickness method and the complete numerical EHL model are used to predict the oil film stiffness. The numerical model mainly consists of the Reynolds equation; the film thickness equation, in which the regular surface roughness is taken into consideration; the force balance equation; and the viscosity-pressure equation. The effects of the normal load, rolling speed, regular surface waviness, and starved lubrication level on the oil film stiffness are investigated.

Measurement of Oil Film Thickness in Cylindrical Roller Bearing by Ultrasound

2014 ◽  
Author(s):  
Kai Zhang ◽  
Qingfeng Meng ◽  
Wei Zhao
Keyword(s):  
Reflection Coefficient ◽  
Film Thickness ◽  
Roller Bearing ◽  
Piezoelectric Element ◽  
Elastohydrodynamic Lubrication ◽  
Spring Model ◽  
Oil Film ◽  
Rolling Element ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

This paper describes the measurement of oil film thickness between rolling element and inner raceway in cylindrical roller bearing. A fine piezoelectric element is bonded on the inner surface of the inner ring to measure the reflection coefficient of oil between rolling element and inner raceway. The quasi-static spring model is used to calculate oil film thickness from the corrected reflection coefficient data. Experiments are described on a simplified cylindrical roller bearing configured by one cylindrical roller, 11ø, and an inner ring from a NU209EM bearing. Reasonable agreement is shown over several loads and speeds with predictions from elastohydrodynamic lubrication (EHL) theory.

Tribological and thermal properties of a crowned gear pair with high-speed and heavy-load in thermal micro-elastohydrodynamic lubrication

2019 ◽  
Vol 234 (4) ◽  
pp. 541-553 ◽  
Author(s):  
Zeliang Xiao ◽  
Xi Shi
Keyword(s):  
Temperature Rise ◽  
High Speed ◽  
Elastohydrodynamic Lubrication ◽  
Loss Ratio ◽  
Flash Temperature ◽  
Heavy Load ◽  
Frictional Loss ◽  
Oil Film ◽  
Gear Drive ◽  
Film Stiffness

The oil film stiffness, temperature rise of oil film, flash temperature and frictional loss ratio of a crowned gear pair with non-Newtonian transient thermal elastohydrodynamic lubrication of rough surfaces in high-speed and heavy-load operating conditions are investigated. The pressure, film thickness, coefficient of friction and temperature rise are calculated along the action line of spur gears to verify the validity of full numerical solution. Subsequently, the effects of high-speed, heavy-load and roughness on those tribological and thermal properties of a crowned gear drive are discussed. The results show that in high-speed, heavy-load and rough surface contact, the crown modification is in favor of stability improvement of gear drive due to smoother curve of oil film stiffness. The temperature rise of the oil film and flash temperature on tooth surface are quite high which are prone to result in gear scuffing. Moreover, small flash temperature and frictional loss ratio occur in the domains near the start of active profile and the tip due to the effect of crown modification.

scholarly journals Film Stiffness Analysis for Angular Contact Ball Bearings Considering Thermal Effect

2015 ◽  
Vol 9 (1) ◽  
pp. 156-159 ◽  
Author(s):  
Chun L. Lei ◽  
Zhi Y. Rui ◽  
Qin Wu ◽  
Jun F. Guo ◽  
Li N. Ren
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Ball Bearing ◽  
Elastohydrodynamic Lubrication ◽  
Calculation Model ◽  
Frictional Heat ◽  
Ball Bearings ◽  
Angular Contact Ball Bearing ◽  
Calculation Results ◽  
Film Stiffness

In order to more accurately calculate the film stiffness of angular contact ball bearing, it is necessary to establish the film stiffness calculation model that is consistent with reality. The frictional heat exists in high-speed ball bearings, and can impact on oil film thickness and stiffness. The calculation model of film stiffness of an angular contact ball bearing taking account of the effects of viscous heating was proposed based on the elastohydrodynamic lubrication theory. The central film thickness and film stiffness have been determined. An example was calculated with this derived equation and the result was compared with that given in other literatures. The calculation results show that the central film thickness decreases and the film stiffness increases when friction heating are considered.

Instrumentation of a Rolling Bearing With a Thin Film Piezo Coating for Oil Film Measurement

2007 ◽  
Author(s):  
R. S. Dwyer-Joyce ◽  
J. Zhang ◽  
B. W. Drinkwater ◽  
J. Elgoyen ◽  
K. J. Kirk
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Contact Region ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Oil Film ◽  
Deep Groove ◽  
Data Points ◽  
Bearing Loads ◽  
Piezoelectric Thin Film

This paper describes a novel design of oil-film monitoring sensor capable of measuring oil-film thickness in concentrated contacts. The approach is to use a thin (approx. 4 μm) sputtered coating of piezoelectric material, such as Aluminium Nitride. When correctly electroded this acts as an ultrasonic sensor with a usable bandwidth from 20–350 MHz. This sensor allows the interrogation of the small lubricated region between the ball and raceway without any special focusing requirements. Typically the dimensions of the contact region is less than a millimeter wide. This sensor system is then demonstrated experimentally on a deep groove ball bearing with the piezoelectric thin film on the external surface of the bearing outer raceway. The interaction of ultrasound with the oil-film is modeled using a quasi-static spring model and this allows properties such as film thickness to be extracted. The measured thicknesses are shown to agree well those obtained from classical elastohydrodynamic lubrication theory for the high bearing loads and low speeds where several data points can be collected from the contact during a ball passage. Measurement of oil film thickness in the region of 0.1–1 μm is demonstrated.

scholarly journals Grease film thickness measurement in rolling bearing contacts

2020 ◽  
pp. 135065012096127
Author(s):  
Xingnan Zhang ◽  
Romeo Glovnea
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Thickness Measurement ◽  
Lubricant Film ◽  
Rolling Element Bearings ◽  
Lubricant Film Thickness ◽  
Rolling Bearings ◽  
Rolling Element ◽  
Film Thickness Measurement

Rolling bearings are the second most used machine components. They work in what it is called elastohydrodynamic lubrication regime. The geometry of rolling element bearings makes the direct measurement of the lubricant film thickness a challenging task. Optical interferometry is widely used in laboratory conditions for studying elastohydrodynamic lubrication however it cannot be used directly in rolling element bearings thus the only suitable methods are electrical techniques. Of these, film thickness measurement based on electrical capacitance of the contacts has been used in the past by a number of authors. One of the limitations of the capacitance method, when used in rolling bearings, is that it cannot distinguish between the contacts of every rolling element and raceway on one hand and on the other between the inner and outer ring contacts. In the present study the authors used an original test rig which can measure the film thickness for only one ball and separately for the inner and outer rings of a radial ball bearing. This paper thus shows for the first-time results of the lubricant film thickness, at the inner and outer raceways, in grease lubricated rolling bearings.

Research on Elastohydrodynamic Lubrication Theory of Rolling Bearing Type Planetary Friction Transmission Mechanism

2011 ◽  
Vol 199-200 ◽  
pp. 400-403
Author(s):  
Yuan Tao Liu ◽  
Jin Zhi Zhao
Keyword(s):  
Film Thickness ◽  
Life Span ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Lubrication Theory ◽  
Transmission Mechanism ◽  
Operation Performance ◽  
Oil Film

Elastohydrodynamic lubrication theory is adopted in rolling bearing type planetary friction transmission mechanism in this paper. Operation performance and using life-span are improved. Minimal oil film thickness formula is deduced based on the elastohydrodynamic lubrication theory. Relationship curve between minimal oil film thickness and rotate speed is presented. Variation law between minimal oil film thickness and work parameters is given.

Influence of Surface Waviness on the Thermal Elastohydrodynamic Lubrication of an Eccentric-Tappet Pair

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
J. Wang ◽  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Surface Waviness ◽  
Film Pressure ◽  
Oil Film ◽  
Working Cycle ◽  
Temperature Oscillations ◽  
Minimum Film Thickness ◽  
Traction Coefficient ◽  
Oil Film Pressure

The effect of single-sided and double-sided harmonic surface waviness on the film thickness, pressure, and temperature oscillations in an elastohydrodynamically lubricated eccentric-tappet pair has been investigated in relation to the eccentricity and the waviness wavelength. The results show that, during one working cycle, the waviness causes significant fluctuations of the oil film, pressure, and temperature, as well as a reduction in minimum film thickness. Smaller wavelength causes more dramatic variations in oil film. The fluctuations of the pressure, film thickness, temperature, and traction coefficient caused by double-sided waviness are nearly the same compared with the single-sided waviness, but the variations are less intense.

Effects of out-of-contact lubricant channeling on friction and film thickness in starved elastohydrodynamic lubrication point contacts

2016 ◽  
Vol 231 (4) ◽  
pp. 432-440 ◽  
Author(s):  
Fadi Ali ◽  
Ivan Křupka ◽  
Martin Hartl
Keyword(s):  
Film Thickness ◽  
Digital Camera ◽  
Elastohydrodynamic Lubrication ◽  
Contact Condition ◽  
Friction Reduction ◽  
Rolling Element Bearings ◽  
Point Contacts ◽  
Practical Applications ◽  
Rolling Element ◽  
Ball On Disc

This study presents experimental results on the effect of out-of-contact lubricant channeling on the tribological performance of nonconformal contacts under starved lubrication. Channeling of lubricant was carried out by adding a slider with a limited slot for scraping the displaced lubricant on one of mating surfaces (ball). Thus, the scraped lubricant is forced to flow back into the depleted track through the limited slot resulting in robust replenishment. The measurements have been conducted using optical tribometer (ball-on-disc) equipped with a digital camera and torque sensor. The effect of lubricant channeling was compared to the original contact condition by means of measuring friction and film thickness. The results show that the out-of-contact lubricant channeling leads to a significant enhancement of film thickness and friction reduction under starved conditions. Indeed, the starved elastohydrodynamic lubrication contacts transformed to the fully flooded regime after introducing the flow reconditioning. Moreover, the film thickness decay over time, which is common with starved elastohydrodynamic lubrication contacts, has not been observed in the case of lubricant channeling. However, the beneficial effect of lubricant channeling diminishes as the original contact condition tends to the fully flooded regime. The results of this study can be easily implemented in practical applications such as radial and thrust rolling-element bearings.

Sign in / Sign up

Export Citation Format

Share Document