Influence of Solid Body Temperature on the Thermal EHL Behavior in Circular Contacts

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Xiaoling Liu ◽  
Peiran Yang
Keyword(s):  
Body Temperature ◽  
Solid Body ◽  
Dominant Role ◽  
Elastohydrodynamic Lubrication ◽  
The Body ◽  
Lubricating Oil ◽  
Entrainment Velocity ◽  
Lubrication Performance ◽  
Thermal Ehl ◽  
Very High

In order to investigate the influence of the body temperature of contacting solids on the lubrication performance of machine components, such as gears and roller bearings, a full numerical solution for the thermal elastohydrodynamic lubrication (EHL) problem in circular contacts under steady state has been achieved. The analysis assumed that the body temperature is different from the temperature of the supplied lubricating oil. The effects of the body temperature, the slide-roll ratio, and the velocity parameter have been discussed. Results show that if the entrainment velocity is not very high, the solid body temperature plays a dominant role in the EHL behavior; however, the influence of the body temperature decreases as the entrainment velocity increases.

Analysis of Thermal Effect on Elastohydrodynamic Lubrication in Angular Contact Ball Bearing

2015 ◽  
Vol 741 ◽  
pp. 443-448
Author(s):  
Bao Ming Wang ◽  
Xia Lun Yun ◽  
Xing Yao Liao ◽  
Xue Song Mei
Keyword(s):  
Temperature Rise ◽  
High Speed ◽  
Ball Bearing ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Oil Viscosity ◽  
Angular Contact Ball Bearing ◽  
Scanning Method ◽  
Lubrication Performance ◽  
Thermal Ehl

Based on the theory of point contact thermal elastohydrodynamic lubrication (EHL),the mathematical models for the thermal EHL of high-speed angular contact ball bearing are established. Multi-grid method and multigrid integration method are respectively used to calculate out the film pressure and film thickness respectively,and the column-by-column scanning method is used to calculate temperature rise of isothermal EHL and thermal EHL. The calculation results show that, under the pure rolling condition, temperature rise of oil film temperature is mainly caused by the compression work and shear heat at inlet and the heat in contact zone mainly comes from the inlet and the heat conduction around; the temperature rise results in oil viscosity lower and the lubricating film thinner ,in this way it reduces the lubrication performance in contact pair.

scholarly journals The Influence of a Novel Inorganic-Polymer Lubricant on the Microstructure of Interstitial-Free Steel during Ferrite Rolling

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 178
Author(s):  
Ning Kong ◽  
Jie Zhang ◽  
Hongbo Li ◽  
Boyu Wei ◽  
David R. G. Mitchell
Keyword(s):  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Rolling Texture ◽  
Fiber Texture ◽  
Lubricating Oil ◽  
Interstitial Free ◽  
Shear Texture ◽  
Lubrication Performance ◽  
Ferrite Rolling ◽  
Very High

A novel polyphosphate lubricant was used and evaluated during hot (ferrite) rolling of an interstitial-free (IF) steel. The texture evolution of these rolled IF steels have been examined by means of X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) measurements. The polyphosphate lubricant shows an improved lubrication performance in terms of the texture optimization compared with lubricating oil and with unlubricated conditions. The γ-fiber texture is enhanced, and less shear texture is produced. This microstructure is responsible for enhanced drawability of ferrite rolled IF steels. The very high thermal stability of the polyphosphate enabled its use at very high temperatures (from 700 to 800 °C). Rolling temperature exerted limited influence on the resulting rolling texture evolution. The polyphosphate lubricant stabilizes the surface texture and reduces the gradient of shear texture through the thickness. The in-grain shear bands are reduced significantly (48.5%) compared with the unlubricated condition. Measured grain orientations indicate that the favorable texture of {111}<112> along the γ-fiber is developed while the undesired α-fiber texture of {001}<110> is effectively suppressed.

Multilevel Solution of the Elastohydrodynamic Lubrication of Concentrated Contacts in Spiroid Gears

1993 ◽  
Vol 115 (3) ◽  
pp. 481-486 ◽  
Author(s):  
Huang Changhua ◽  
Wen Shizhu ◽  
Huang Ping
Keyword(s):  
Normal Load ◽  
Contact Point ◽  
Elastohydrodynamic Lubrication ◽  
New Method ◽  
Heavy Load ◽  
Entrainment Velocity ◽  
Lubrication Performance ◽  
Ellipticity Ratio

This paper presents a new method for analyzing the lubrication performance of spiroid gears, which combines the elastohydrodynamic lubrication analysis with LTCA. The LTCA provides the geometry of teeth surfaces at the vicinity of contact point, normal load, lubricant entrainment velocity, etc. Multilevel techniques are used to solve the elastohydrodynamic lubrication of concentrated contacts with high ellipticity ratio under heavy load in spiroid gears. Finally, a pair of spiroid gears used in aircraft is analyzed. Some interesting new conclusions are presented.

Coupling analysis of the fatigue life and the TEHL contact behavior of ball screw under the multidirectional load

2020 ◽  
Vol 72 (10) ◽  
pp. 1285-1293
Author(s):  
Jia-Jia Zhao ◽  
Ming-Xing Lin ◽  
Xian-Chun Song ◽  
Nan Wei
Keyword(s):  
Fatigue Life ◽  
Film Thickness ◽  
Peer Review ◽  
Elastohydrodynamic Lubrication ◽  
Contact Model ◽  
Ball Screw ◽  
Content Type ◽  
Entrainment Velocity ◽  
Contact Points ◽  
Lubrication Performance

Purpose This paper aims to provide thermal elastohydrodynamic lubrication (TEHL) contact model to study all balls’ lubrication performance of the ball screw when the multidirectional load is applied. Design/methodology/approach A new TEHL contact model combining the multidirectional load and the roughness surface texture is established to describe fatigue life of the ball screw. Meanwhile, the authors use the Reynolds equation to study the lubrication performance of the ball screw. Findings When the multidirectional load is applied, contact load, slide-roll ratio and entrainment velocity of all balls have a periodic shape. The TEHL performance values at the ball-screw contact points including contact stress, shear stress, minimum film thickness and temperature rise are higher than that at the ball-nut contact points. The TEHL performance values increase with the increase of root mean square (RMS) except for the film thickness. In addition, the radial load of the ball screw has a significant effect on the fatigue life. Originality/value The results of the studies demonstrate the new TEHL contact model that provides the instructive significance to analyze the fatigue life of the ball screw under the multidirectional load. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0097/

Design and Experiment Study on a New Type of Lubrication Simulation System for Thrust-Ball Bearing in Confined Space

2017 ◽  
Vol 873 ◽  
pp. 303-307
Author(s):  
Feng Li ◽  
Feng Guo ◽  
Guan Gyuan Liu ◽  
Zhang Gang
Keyword(s):  
Film Thickness ◽  
Ball Bearing ◽  
Elastohydrodynamic Lubrication ◽  
Simulation System ◽  
Operating Conditions ◽  
Confined Space ◽  
Entrainment Velocity ◽  
Lubrication Performance ◽  
New Type ◽  
The Relationship

Many machine components work within an elastohydrodynamic lubrication (EHL) regime. Unconfined space is widely used in EHL formulas for to evaluate film thickness, which is related to operating conditions and material properties. In classical theoretical EHL studies, film pressure matches the loading balance and the location of the lubricated components can be adjusted. In the present study, the lubrication performance is analyzed based on a confined space. A thrust ball bearing lubrication simulation system is designed and used to examine the relationship between velocity and film thickness. It was found that the central film thickness and minimum film thickness increased as entrainment velocity increased. Fluctuations in the film thickness curve were observed, which may have arisen from slight gap variations in the ball-plate contact area.

The Behavior of Non-Newtonian Thermal EHL Film in Line Contacts at Dynamic Loads

1992 ◽  
Vol 114 (1) ◽  
pp. 81-85 ◽  
Author(s):  
Peiran Yang ◽  
Shizhu Wen
Keyword(s):  
Iterative Procedure ◽  
Elastohydrodynamic Lubrication ◽  
Dynamic Loads ◽  
Lubrication Film ◽  
Load Frequency ◽  
Line Contacts ◽  
Pressure Peak ◽  
Inlet Zone ◽  
Thermal Ehl ◽  
Very High

The behavior of the thermal elastohydrodynamic lubrication film in line contacts at dynamic loads is investigated numerically with a forward-iterative procedure. The lubricant is assumed to be an Eyring fluid. The results show that the effects of the dynamic loads upon the time depending EHL film include two aspects: to retard the change and to increase the thickness of the film. In the case the load frequency is very high, a pressure peak which is round in shape can be found in the inlet zone of the contact.

scholarly journals Influence of the cage on the migration and distribution of lubricating oil inside a ball bearing

Friction ◽  
2021 ◽  
Author(s):  
He Liang ◽  
Yu Zhang ◽  
Wenzhong Wang
Keyword(s):  
Capillary Flow ◽  
Elastohydrodynamic Lubrication ◽  
Rolling Bearing ◽  
Lubricating Oil ◽  
Lubricant Oil ◽  
Disc Model ◽  
Lubrication Performance ◽  
Custom Made ◽  
Bearing Design ◽  
Ball On Disc

AbstractThe migration and distribution of lubricant oil in a rolling bearing strongly affect the elastohydrodynamic lubrication performance between the balls and rings. However, oil re-lubrication is highly dependent on the bearing design, which is different from the ball-on-disc model. This study directly observed the distribution of the lubricant film in a custom-made model-bearing rig, with an outer ring replaced by a glass ring to allow full optical access. The influence of the cage type and surface properties were presented. The physical origin of the re-lubrication mechanism, including capillary flow and mechanical redistribution, was discussed.

Antipyretic Plants: An Updated Review

2020 ◽  
Vol 16 (1) ◽  
pp. 4-12
Author(s):  
Vandana Garg ◽  
Rohit Dutt
Keyword(s):  
Side Effects ◽  
Body Temperature ◽  
Medicinal Plants ◽  
Inflammatory Mediators ◽  
Review Paper ◽  
The Body ◽  
Hypothalamic Area ◽  
Antipyretic Activity ◽  
Disease States ◽  
Elevated Body Temperature

Background: Fever, is known as pyrexia, may occur due to infection, inflammation, or any tissue damage and disease states. Normally, the infected or damaged tissue initiates the enhanced formation of pro-inflammatory mediators like cytokines which further increases the synthesis of prostaglandin E2 (PgE2) near the hypothalamic area and thereby trigger the hypothalamus to elevate the body temperature. Objective: Antipyretics are the agents which reduce the elevated body temperature. The most commonly used antipyretic agent, paracetamol, may be fatal due to its side effects. Methods: In this review paper, Chemical Abstracts, Google Scholar, PubMed, and Science Direct were the sources for the published article to collect information regarding antipyretic activity. Results: This review compiles the antipyretic plants that may be useful to treat fever due to various diseases. Conclusion: These medicinal plants could be good alternatives for traditional allopathic antipyretics.

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