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 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.

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.

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.

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.

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.

Development of an Efficient Oil Film Damper for Improving the Control of Rotor Vibration

1991 ◽  
Vol 113 (4) ◽  
pp. 557-562 ◽  
Author(s):  
Shiping Zhang ◽  
Litang Yan
Keyword(s):  
High Speed ◽  
Porous Metal ◽  
Porous Matrix ◽  
Squeeze Film ◽  
Oil Film ◽  
Squeeze Film Damper ◽  
Outer Race ◽  
Typical Experiment ◽  
Stiffness And Damping ◽  
Film Stiffness

An efficient oil film damper known as a porous squeeze film damper (PSFD) was developed for more effective and reliable vibration control of high-speed rotors based on the conventional squeeze film damper (SFD). The outer race of the PSFD is made of permeable sintered porous metal materials. The permeability allows some of the oil to permeate into and seep out of the porous matrix, with remarkable improvement of the squeeze film damping properties. The characteristics of PSFD oil film stiffness and damping coefficients and permeability, and also, the steady-state unbalance response of a simple rigid rotor and flexible Jeffcott’s rotor supported on PSFD and SFD are investigated. A typical experiment is presented. Investigations show that the nonlinear vibration characteristics of the unpressurized SFD system such as bistable jump phenomena and “lockup” at rotor pin-pin critical speeds could be avoided and virtually disappear under much greater unbalance levels with properly designed PSFD system. PSFD has the potential advantage of operating effectively under relatively large unbalance conditions.

The Effect of Starvation on a Thermal Mixed EHL Line Contact

2019 ◽  
Author(s):  
Sheng Li ◽  
Danielle Masse
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Elastohydrodynamic Lubrication ◽  
Flash Temperature ◽  
Lubrication Film ◽  
Line Contacts ◽  
Lubrication Condition ◽  
Scuffing Failure ◽  
Inlet Zone ◽  
Viscosity Dependence

Abstract To investigate the effect of the inlet starvation severity on the flash temperature, which dictates the scuffing failure, a thermal mixed elastohydrodynamic lubrication model is developed for line contacts operating under the starved lubrication condition. The scuffing failure of high speed gearing applications is commonly associated with the very high sliding condition occurring in the vicinity of either the root or the tip, where the shear thinning effect that decreases the lubrication film thickness and increases the contact pressure is significant. Utilizing a generalized Newtonian Reynolds equation, the lubricant viscosity dependence on the shear rate, as well as on the pressure and temperature, is incorporated for the proper and accurate modeling of the tribological behavior under the high sliding condition. A film fraction parameter is employed in the Reynolds equation to include the starvation and cavitation description, eliminating the need for the measured or assumed meniscus location in the inlet zone. Considering different operating and surface roughness conditions, a parametric study is performed to show an asymptotic relationship between the flash temperature and the inlet starvation severity.

The Performance of Ball Bearings With Silicon Nitride Ceramic Balls in High Speed Spindles for Machine Tools

1988 ◽  
Vol 110 (4) ◽  
pp. 693-698 ◽  
Author(s):  
Hirotoshi Aramaki ◽  
Yoshio Shoda ◽  
Yuka Morishita ◽  
Takeshi Sawamoto
Keyword(s):  
Silicon Nitride ◽  
Temperature Rise ◽  
Machine Tools ◽  
High Speed ◽  
Low Cost ◽  
Steel Ball ◽  
Ball Bearings ◽  
Grease Lubrication ◽  
Frictional Loss ◽  
High Speeds

Two types of angular contact ball bearings for machine tools having steel rings and silicon nitride balls were tested and the temperature rise was compared with that of conventional steel ball bearings with grease lubrication and oil-air lubrication as well. Experimental results indicated that the temperature rise of silicon nitride ball bearings was much lower than that of steel ball bearings at high speeds. Calculations made using a computer demonstrated that the reduction of gyroscopic moments and centrifugal forces acting on balls because of the low density of silicon nitride resulted in about 30 to 50 percent less frictional loss at high speeds even with low-cost lubrication such as grease or oil-air.

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