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/

An improved TEHL analysis of textured roller bearings consider various texture parameters and slip

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junning Li ◽  
Ka Han ◽  
Wuge Chen ◽  
Xiaojie Tang ◽  
Qian Wang
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Contact Area ◽  
Surface Texturing ◽  
Elastohydrodynamic Lubrication ◽  
Content Type ◽  
Roller Bearings ◽  
Texture Parameters ◽  
Lubrication Performance ◽  
Texture Size

Purpose The purpose of this study is to reveal the lubrication performance of textured roller bearings under various texture size, texture depth, texture types and slip. Design/methodology/approach In the present study, the improved thermal elastohydrodynamic lubrication method based on the surface texturing of the textured roller bearings is proposed, and then the effect of texture size, texture depth, texture types and slip on the contact pressure, film thickness and temperature distribution are analyzed systematically. Findings The results show that the pressure decreases and the film thickness increases on the contact area because of the surface texturing. The temperature increases first and then decreases as the texture size increases, and then the temperature increases as the texture depth and the slip increases. Compared to circle and square texture, cross texture can obviously decrease the temperature on the contact area. The effectiveness of the proposed method is verified. Originality/value This study can help to reduce friction and wear of textured roller bearings. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2020-0318/

Effect of angular speed of cam on oil film variation in the line contact thermal EHL of a cam-tappet pair

2020 ◽  
Vol 72 (6) ◽  
pp. 713-722
Author(s):  
Hongwei Tang ◽  
Jing Wang ◽  
Nannan Sun ◽  
Jianrong Zhu
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Elastohydrodynamic Lubrication ◽  
Grid Method ◽  
Angular Speed ◽  
Content Type ◽  
Sliding Motion ◽  
Oil Characteristics ◽  
Thermal Ehl ◽  
Wedge Effect

Purpose The influence of the cam angular speed on the pressure, film thickness and temperature profiles at some selected angular positions together with the oil characteristics are investigated. Design/methodology/approach A high-order polynomial cam is used, and thermal elastohydrodynamic lubrication (EHL) calculations are carried out by the multi-grid method and line-line scanning technique. Findings It is found that the film thickness decreases with a decrease in angular speed. The depth of the dimple that occurred in the reverse motion is also reduced because of the recession in the “temperature–viscosity wedge” effect. Originality/value It is revealed that the reduction in the cam angular speed makes the classical big surface dimple evolve into a small centralized dimple during the opposite sliding motion. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0327

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.

Transient elastohydrodynamic lubrication analysis of spur gears running-in considering effects of solid particles and surface roughness

2016 ◽  
Vol 68 (2) ◽  
pp. 183-190 ◽  
Author(s):  
Xingbao Huang ◽  
Youqiang Wang
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Solid Particles ◽  
Maximum Pressure ◽  
Spur Gears ◽  
Content Type ◽  
Lubrication Performance ◽  
Minimum Film Thickness ◽  
Variant Effect

Purpose – This paper aims to investigate the mechanism of spur gears running-in and to solve the lubrication problems of teeth running-in. Design/methodology/approach – The elastohydrodynamic lubrication (EHL) model considering solid particles was established by applying multi-grid and multiple-grid integration methods to the numerical solution. Findings – In the region where debris settle, transient pressure increases sharply, and a noticeable increase in the running-in load causes a remarkable increase in both the centre and maximum pressures and a slight increase in the minimum film thickness. Roughness wavelength makes a considerable difference to the minimum film thickness at double-to-single tooth transient. A considerable increase in rotation velocity can cause a remarkable reduction in both the centre and maximum pressures but an amazing increase in the minimum film thickness. The effects of roughness amplitude on the maximum pressure are considerably distinct. Research limitations/implications – Research on EHL of spur gears in the running-in process considering solid particles, surface roughness and time-variant effect is meaningful to practical gears running-in. Thermal effect can be included in the next study. Practical implications – The analysis results can be applied to predict and improve lubrication performance of the meshing teeth. Social implications – The aim is to reduce gears’ manufacture and running-in costs and improve economic performance. Originality/value – The EHL model that considers solid particles was established. The Reynolds equation was deduced taking the effects of solid particles into account. The EHL of spur gears running-in was investigated considering the time-variant effect, surface roughness, running-in load and rotation speed.

A Starved Mixed Elastohydrodynamic Lubrication Model for the Prediction of Lubrication Performance, Friction and Flash Temperature With Arbitrary Entrainment Angle

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Wei Pu ◽  
Dong Zhu ◽  
Jiaxu Wang
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Flash Temperature ◽  
Machined Surface ◽  
Lubrication Performance ◽  
Wide Range ◽  
Starved Lubrication

In this study, a modified mixed lubrication model is developed with consideration of machined surface roughness, arbitrary entraining velocity angle, starvation, and cavitation. Model validation is executed by means of comparison between the obtained numerical results and the available starved elastohydrodynamic lubrication (EHL) data found from some previous studies. A comprehensive analysis for the effect of inlet oil supply condition on starvation and cavitation, mixed EHL characteristics, friction and flash temperature in elliptical contacts is conducted in a wide range of operating conditions. In addition, the influence of roughness orientation on film thickness and friction is discussed under different starved lubrication conditions. Obtained results reveal that inlet starvation leads to an obvious reduction of average film thickness and an increase in interasperity cavitation area due to surface roughness, which results in significant increment of asperity contacts, friction, and flash temperature. Besides, the effect of entrainment angle on film thickness will be weakened if the two surfaces operate under starved lubrication condition. Furthermore, the results show that the transverse roughness may yield thicker EHL films and lower friction than the isotropic and longitudinal if starvation is taken into account. Therefore, the starved mixed EHL model can be considered as a useful engineering tool for industrial applications.

Effect of tooth waist order parameters of double involute gears on lubrication performance of gear drive

2016 ◽  
Vol 68 (6) ◽  
pp. 671-675 ◽  
Author(s):  
Zhimin Fan ◽  
Wanfeng Zhou ◽  
Ruixue Wang ◽  
Na Wang
Keyword(s):  
Elastohydrodynamic Lubrication ◽  
Reference Value ◽  
Tooth Profile ◽  
Order Parameters ◽  
Content Type ◽  
Oil Film ◽  
Gear Drive ◽  
Involute Gear ◽  
Lubrication Performance ◽  
Involute Gears

Purpose The purpose of this paper is to derive a new lubrication model of double involute gears drive and study the effect of the tooth waist order parameters of double involute gears on lubrication performance. Design/methodology/approach The new lubrication model of double involute gears drive was established according to the meshing characteristics of double involute gears drive and the finite length line contact elastohydrodynamic lubrication theory. Numerical calculation of the lubrication model of gear drive was conducted using the multigrid method. Findings The results show that the oil film necking phenomenon and the oil film pressure peak emerged at the tooth waist order area and the tooth profile ends, and when compared with involute gear, the lubrication performance at the tooth waist order area is better than that at the tooth profile ends. The effect of tooth waist order parameters on lubrication performance at the tooth waist order area was greater than that at other areas. Originality/value This research will promote the application of the double involute gear as soon as possible, and it has the reference value for other types of gears.

Effects of polymers concentration on EHL film-forming in point contacts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liangwei Qiu ◽  
Xiaoyang Chen ◽  
Fakai Dong
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Point Contact ◽  
High Concentration ◽  
Content Type ◽  
Base Oils ◽  
Low Viscosity ◽  
Lubricant Oil ◽  
Pure Rolling ◽  
Film Forming

Purpose This paper aims to experimentally investigate the film-forming capability of base oils containing poly-methacrylate (PMA) and poly-isobutene (PIB), in a point contact under pure rolling. Design/methodology/approach By using the relative light intensity method, the film thickness is calculated from the interferometer images which are captured by multiple-contact optical elastohydrodynamic lubricated test rig. Findings The test results reveal that polymers, both PMA and PIB, have a significant contribution to the film-forming capability of base oils and the film thickness increases with concentration. The forming-film capabilities for PMA and PIB in base oils are similar at low concentration, while PIB gives a higher film thickness than PMA at high concentration. Shear-thinning phenomenon are observed in all polymer-based oils. Originality/value The polymer usually as an additive is added into the low viscosity base oils to improve the properties of lubricant oil. This paper reports the lubricated properties of PMA and PIB with different concentrations in base oils and to evaluate their functional mechanism in a point contact. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0263/

Effect of pin generatrix on the elastohydrodynamic lubrication performance of pin-bush pair in industrial roller chains

2021 ◽  
pp. 135065012110659
Author(s):  
Ansheng Zhang ◽  
Jing Wang ◽  
Yiming Han ◽  
Jianjun Zhang ◽  
Yi Liu
Keyword(s):  
Film Thickness ◽  
Working Condition ◽  
Elastohydrodynamic Lubrication ◽  
Test Rig ◽  
Stroke Length ◽  
Oil Supply ◽  
Supply Condition ◽  
Lubrication Performance ◽  
Custom Made ◽  
Disk Test

For industrial roller or bush chains, the bush swings relative to the pin at working condition. If proper lubrication is maintained, an elastohydrodynamic lubrication contact is formed between the pin and the bush. In this study, a custom-made pin was used to replace the steel ball of a ball-disk test rig and optical interferometric experiments were carried out to study the effect of pin generatrix on the lubrication performance. The effects of generatrix shape, stroke length and oil supply condition on the lubrication state were explored. It is found that the change of the generatrix has an important influence on the oil film thickness, especially under rare oil supply condition.

Size effect on thermal elastohydrodynamic lubrication of industrial chain bush-pin hinge pair

2019 ◽  
Vol 71 (9) ◽  
pp. 1080-1085 ◽  
Author(s):  
Mingyu Zhang ◽  
Jing Wang ◽  
Yi Liu ◽  
Longjie Dai ◽  
Zhaohua Shang
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Temperature Rise ◽  
Elastohydrodynamic Lubrication ◽  
Curvature Radius ◽  
Line Contact ◽  
Content Type ◽  
Oil Film ◽  
Industrial Chain ◽  
Infinite Line

Purpose The purpose of this paper is to use elastohydrodynamic lubrication (EHL) theory to study the variation of the equivalent curvature radius “R” on the change of oil film thickness, pressure, temperature rise and friction coefficient in the contact zone between bush-pin in industrial chain drive. Design/methodology/approach In this paper, the contact between bush and pin is simplified as infinitely long line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. The two constitutive equations, namely, Newton fluid and Ree–Eyring fluid are used in the calculations. Findings It is found that with the increase of equivalent curvature radius, the thickness of oil film decreases and the temperature rise increases. Under the same condition, the friction coefficient of Newton fluid is higher than that of Ree–Eyring fluid. When the load increases, the oil film thickness decreases, the temperature rise increases and the friction coefficient decreases; and the film thickness increases with the increase of the entraining speed under the condition “R < 1,000 mm”. Research limitations/implications The infinite line contact assumption is only an approximation. For example, the distances between the two inner plates are 5.72 mm, by considering the two parts assembled into the inner plates, the total length of the bush is less than 6 mm. The diameter of the pin and the bore diameter of the bush are 3.28 and 3.33 mm. However, the infinite line contact is also helpful in understanding the general variation of oil film characteristics and provides a reference for the future study of finite line contact of chain problems. Originality/value The change of the equivalent radius R on the variation of the oil film in the contact of the bush and the pin in industrial chain drive was investigated. The size effect influences the lubrication characteristic greatly in the bush-pin pair.

A thermal EHL investigation for size effect of finite line contact on bush-pin hinge pairs in industrial chains

2020 ◽  
Vol 72 (5) ◽  
pp. 695-701
Author(s):  
Mingyu Zhang ◽  
Jing Wang ◽  
Peiran Yang ◽  
Zhaohua Shang ◽  
Yi Liu ◽  
...  
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Contact Zone ◽  
Line Contact ◽  
Equivalent Radius ◽  
Content Type ◽  
Oil Film ◽  
Finite Line Contact ◽  
Finite Line ◽  
Thermal Ehl

Purpose This paper aims to study the influence of the dimension change of bush-pin on the pressure, oil film thickness, temperature rise and traction coefficient in contact zone by using a thermal elastohydrodynamic lubrication (EHL) model for finite line contact. Concretely, the effects of the equivalent curvature radius of the bush and the pin, and the length of the bush are investigated. Design/methodology/approach In this paper, the contact between the bush and pin is simplified as finite line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. A constitutive equation Ree–Eyring fluid is used in the calculations. Findings It is found that by selecting an optimal equivalent radius of curvature and prolonging the bush length can improve the lubrication state effectively. Originality/value Under specific working conditions, there exists an optimal equivalent radius to maximize the minimum oil film thickness in the contact zone. The increase of generatrix length will weaken the stress concentration effect in the rounded corner area at both ends of the bush, which can improve the wear resistance of chain. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0448.

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