Effects of reciprocating motion parameters on lubricating properties of tripod sliding universal joints

2014 ◽  
Vol 66 (1) ◽  
pp. 111-123 ◽  
Author(s):  
X.F. Wang ◽  
R.F. Hu ◽  
K.S. Wang ◽  
H.R. Cui
Keyword(s):  
Film Thickness ◽  
Geometrical Model ◽  
Reciprocating Motion ◽  
Content Type ◽  
Entrainment Velocity ◽  
Pressure Peak ◽  
New Type ◽  
Sweeping Method ◽  
Motion Parameters ◽  
Bounding Surfaces

Purpose – This paper aims to clarify the effects of the reciprocating motion parameters on the lubricating performance of the tripod sliding universal joint (TSUJ). These parameters mainly include the frequency and amplitude of the reciprocating motion. This work will explain how the film thickness and pressure as well as the temperature vary with the frequency and amplitude of the reciprocating motion in order to improve the lubricating performance of the TSUJ and extend its working life. Design/methodology/approach – Based on the simplified geometrical model derived from the main mating surfaces, the effects of the frequency and amplitude on the pressure and film thickness as well as the temperature are theoretically investigated. In this work, multi-level method, multilevel multi-integration method and sequential line sweeping method were applied to solving Reynolds equation, the elastic deformation of the bounding surfaces and temperature, respectively. Findings – The overall film thickness increases with the increase of the amplitude or frequency. The consumed time of the rippled film passing through the contact zone hardly depends on the amplitude or frequency. The variation of the film or temperature lags behind the variation of the entrainment velocity. Increasing amplitude or frequency increases the temperature. The effect of the amplitude or frequency on the pressure focuses mainly on the second pressure peak. Originality/value – TSUJ is a new-type tripod joint and the obtained results are of great value for its design and application.

Numerical investigation on single dent in EHL point contacts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Qiancheng Qin ◽  
Xue-Feng Wang ◽  
Rufu Hu ◽  
Xiaomin Cheng
Keyword(s):  
Film Thickness ◽  
Maximum Pressure ◽  
Point Contacts ◽  
Governing Equations ◽  
Content Type ◽  
Entrainment Velocity ◽  
Minimum Film Thickness ◽  
Input Parameters ◽  
Pressure Peak ◽  
Lubricating Properties

Purpose This study aims to investigate the effects of single dent on the film thickness and pressure in elastohydrodynamically lubricated (EHL) point contacts by numerical analysis. Design/methodology/approach The governing equations of single dent were established and then the variations of the film thickness and pressure induced by the applied load, the entrainment velocity and the ball radius were investigated. Meanwhile, the film thickness and pressure under smooth and dented surfaces were compared with each other. Findings The dent enhances both the maximum pressure and the second pressure peak. The minimum film thickness arises before the dent under certain conditions. In the meantime, the pressure decreases at the inside of the dent and the film thickness is just the reverse. The entrainment velocity remarkably affects the overall film thickness, whereas the rest of the input parameters mainly decides the details of the film curve. All input parameters remarkably affect the overall pressure, especially the maximum pressure. Originality/value This work is helpful to understanding the effect of the single dent on the lubricating properties of EHL point contacts.

A thermal EHL investigation on plate-pin hinge pairs in silent chains using a narrow finite line contact

2020 ◽  
Vol 72 (10) ◽  
pp. 1139-1145
Author(s):  
Mingyu Zhang ◽  
Jing Wang ◽  
Jinlei Cui ◽  
Peiran Yang
Keyword(s):  
Film Thickness ◽  
Temperature Rise ◽  
Elastohydrodynamic Lubrication ◽  
Radius Of Curvature ◽  
Line Contact ◽  
Equivalent Radius ◽  
Content Type ◽  
Finite Line Contact ◽  
Pressure Peak ◽  
Finite Line

Purpose The purpose of this paper is to numerically study the variations of oil film pressure, thickness and temperature rise in the contact zone of plate-pin pair in silent chains. Design/methodology/approach A steady-state thermal elastohydrodynamic lubrication (EHL) model is built using a Ree–Eyring fluid. The contact between the plate and the pin is simplified as a narrow finite line contact, and the lubrication state is examined by varying the geometry and the plate speed. Findings With increase in the equivalent radius of curvature, the pressure peak and the central film thickness increase. Because the plate is very thin, the temperature rise can be neglected. Even when the influence of the rounded corner region is less, a proper design can beneficially increase the minimum film thickness at both edges of the plate. Under a low entraining speed, strong stress concentration results in close-zero film thickness at both edges of the plate. Originality/value This study reveals the EHL feature of the narrow finite line contact in plate-pin pairs for silent chains and will support the future works considering transient effect, surface features and wear.

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.

Toward a theory on workplaces for smart workers

Facilities ◽  
2019 ◽  
Vol 38 (3/4) ◽  
pp. 298-315
Author(s):  
Luisa Errichiello ◽  
Tommasina Pianese
Keyword(s):  
Web Sites ◽  
Participant Observation ◽  
Secondary Data ◽  
Primary Data ◽  
Innovative Design ◽  
Content Type ◽  
New Type ◽  
Smart Working ◽  
Research Propositions

Purpose The purpose of this paper is to identify the main features of smart work centers (SWCs) and show how these innovative offices would support the implementation of smart working and related changes in workspaces (“bricks”), technologies (“bytes”) and organizational practices (“behaviors”). Design/methodology/approach In this study, scientific literature is combined with white papers and business reports and visits to 14 workplaces, including offices designed as SWCs, co-working spaces, one telecenter, one accelerator and one fab lab. Primary data were collected through interviews with managers and users and non-participant observation, whereas secondary data included web-sites, brochures, presentations, press releases and official documents. Findings The authors developed research propositions about how the design of spaces and the availability of technology within SWCs would support the “bricks” and “bytes” levers of smart working. More importantly, the authors assumed that this new type of workplace would sustain changes in employees’ behaviors and managers’ practices, thus helping to overcome several challenges traditionally associated with remote working. Research limitations/implications The exploratory nature of the research only provides preliminary information about the role of SWCs within smart working programs. Additional qualitative and quantitative empirical investigation is required. Practical implications This study provides valuable knowledge about how the design of corporate offices can be leveraged to sustain the implementation of smart working. Originality/value This study advances knowledge on workplaces by focusing on an innovative design of traditional offices (SWC). It also lays the foundations for future investigation aimed at testing the developed propositions.

Experimental study of pin surface precision on lubrication behavior of pin–bush pairs in industrial roller chains

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ansheng Zhang ◽  
Mingyu Zhang ◽  
Jing Wang ◽  
Jianjun Zhang ◽  
Zhaohua Shang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Design Methodology ◽  
Industrial Applications ◽  
Experimental Basis ◽  
Reciprocating Motion ◽  
Content Type ◽  
Oil Supply ◽  
Machining Errors ◽  
Surface Precision ◽  
Straightness Error

Purpose The purpose of this paper is to study the influence of surface precision on the lubrication state of the roller chain under adequate and rare oil supply conditions, respectively. Design/methodology/approach The straightness error and roughness error of the pin generatrices were measured and the influence of surface precision on the lubrication behavior under steady state and reciprocating motion was studied through optical interference experiments. Findings The lubrication state is strongly influenced by the surface precision of the roller surface both under adequate oil supply and rare oil supply conditions. Originality/value In industrial applications, the machining errors of parts cannot be completely eliminated. Studying the influence of the surface precision on the lubrication behavior of pin–bush pairs can provide the experimental basis for the optimal design of the bush roller chains.

scholarly journals Establishment and Application of Rapid Diagnosis for Reverse Transcription-Quantitative PCR of Newly Emerging Goose-Origin Nephrotic Astrovirus in China

mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
Xiaoyuan Yuan ◽  
Kai Meng ◽  
Yuxia Zhang ◽  
Lihong Qi ◽  
Wu Ai ◽  
...  
Keyword(s):  
Quantitative Pcr ◽  
Clinical Application ◽  
Reverse Transcription ◽  
Test Sample ◽  
Sensitivity Testing ◽  
Content Type ◽  
Reverse Transcription Quantitative Pcr ◽  
Emerging Virus ◽  
New Type ◽  
And Control

ABSTRACT In 2017, a new type of goose-origin astrovirus (GoAstV) that is completely different from previously identified avian astroviruses (which have only 30.0% to 50.5% homology with GoAstV) has been isolated from diseased geese in China. This disease can cause joint swelling in sick geese, and the anatomy shows a clear precipitation of urate in the kidney. The rate of death and culling can reach more than 30%, revealing the disease’s severe pathogenicity. To quickly and accurately diagnose the newly emerging disease, we established a highly specific reverse transcription-quantitative PCR (RT-qPCR) method of detecting GoAstV. Sensitivity testing showed that the minimum amount of test sample for this method is 52.5 copies/μl. Clinical application confirmed that this method can quickly and effectively detect GoAstV, providing a diagnostic platform for the prevention and control of goose disease. IMPORTANCE Goose-origin astrovirus (GoAstV), as a newly emerging virus in 2017, is different from previously known astroviruses in the genus Avastrovirus. So far, few studies have focused on the novel virus. Considering the infectious development of astrovirus (AstV), we established a reverse transcription-quantitative PCR (RT-qPCR) assay with a strong specificity to quickly and accurately diagnose GoAstV. Confirmed by clinical application, this method can quickly and accurately detect prevalent GoAstV. The assay is thus convenient for clinical operation and is applicable to the monitoring of GoAstV disease.

scholarly journals A Bacterial Microcompartment Is Used for Choline Fermentation byEscherichia coli536

2018 ◽  
Vol 200 (10) ◽  
Author(s):  
Taylor I. Herring ◽  
Tiffany N. Harris ◽  
Chiranjit Chowdhury ◽  
Sujit Kumar Mohanty ◽  
Thomas A. Bobik
Keyword(s):  
Electron Microscopy ◽  
Heart Disease ◽  
Gene Cluster ◽  
Transcriptional Regulator ◽  
Human Gut ◽  
Content Type ◽  
E Coli ◽  
Bacterial Microcompartment ◽  
New Type ◽  
Insight Into

ABSTRACTBacterial choline degradation in the human gut has been associated with cancer and heart disease. In addition, recent studies found that a bacterial microcompartment is involved in choline utilization byProteusandDesulfovibriospecies. However, many aspects of this process have not been fully defined. Here, we investigate choline degradation by the uropathogenEscherichia coli536. Growth studies indicatedE. coli536 degrades choline primarily by fermentation. Electron microscopy indicated that a bacterial microcompartment was used for this process. Bioinformatic analyses suggested that the choline utilization (cut) gene cluster ofE. coli536 includes two operons, one containing three genes and a main operon of 13 genes. Regulatory studies indicate that thecutXgene encodes a positive transcriptional regulator required for induction of the maincutoperon in response to choline supplementation. Each of the 16 genes in thecutcluster was individually deleted, and phenotypes were examined. ThecutX,cutY,cutF,cutO,cutC,cutD,cutU, andcutVgenes were required for choline degradation, but the remaining genes of thecutcluster were not essential under the conditions used. The reasons for these varied phenotypes are discussed.IMPORTANCEHere, we investigate choline degradation inE. coli536. These studies provide a basis for understanding a new type of bacterial microcompartment and may provide deeper insight into the link between choline degradation in the human gut and cancer and heart disease. These are also the first studies of choline degradation inE. coli536, an organism for which sophisticated genetic analysis methods are available. In addition, thecutgene cluster ofE. coli536 is located in pathogenicity island II (PAI-II536) and hence might contribute to pathogenesis.

Analysis on sealing performance of VL seals based on mixed lubrication theory

2019 ◽  
Vol 71 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Shixian Xu ◽  
Zhengtao Su ◽  
Jian Wu
Keyword(s):  
Finite Element ◽  
Film Thickness ◽  
Finite Element Model ◽  
Friction Factor ◽  
Contact Pressure ◽  
Element Model ◽  
Mixed Lubrication ◽  
Content Type ◽  
Deformation Mechanics ◽  
The Finite Element Model

Purpose This paper aims to research the influence of pressure, friction factors, roughness and actuating speed to the mixed lubrication models of outstroke and instroke. Design/methodology/approach Mixed lubrication model is solved by finite volume method, which consists of coupled fluid mechanics, deformation mechanics and contact mechanics analyses. The influence of friction factor on the finite element model is also considered. Then, contact pressure, film thickness, friction and leakage have been studied. Findings It was found that the amount of leakage is sensitive to the film thickness. The larger the film thickness is, the greater the influence received from the friction factor, however, the effect of oil film on the friction is negligible. The friction is determined mainly by the contact pressure. The trend of friction and leakage influenced by actuating velocity and roughness is also obtained. Originality/value The influence of friction factor on the finite element model is considered. This can make the calculation more accurate.

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