Lubrication Phenomena in Spur Gears: Capacity, Film Thickness Variation, and Efficiency

1965 ◽  
Vol 87 (3) ◽  
pp. 655-663 ◽  
Author(s):  
R. Wayne Adkins ◽  
E. I. Radzimovsky
Keyword(s):  
Shear Stress ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Power Loss ◽  
Hydrodynamic Lubrication ◽  
Thickness Variation ◽  
Spur Gears ◽  
Oil Film ◽  
Lubrication Conditions ◽  
Lubricant Viscosity

In this paper the oil film separating the mating surfaces of involute spur gears operating under hydrodynamic lubrication conditions is analyzed. This analysis surpasses previous analyses in as much as the actual motion of the involute profiles (rolling, sliding, and squeezing motion) and the total number of teeth engaged at any one time are considered. Expressions are derived for the pressure distribution, shear stress, and power loss in the oil film at any phase of tooth engagement. A method is developed by which these expressions can be applied to determine the film thickness at any instant and the power loss for a given load, speed, and lubricant viscosity.

Analysis of Tribological Performance of Piston Ring Lubrication

2011 ◽  
Author(s):  
Yibin Guo ◽  
Wanyou Li ◽  
Dequan Zou ◽  
Xiqun Lu ◽  
Tao He
Keyword(s):  
Film Thickness ◽  
Friction Force ◽  
Power Loss ◽  
Piston Ring ◽  
Design Parameters ◽  
Oil Film ◽  
Starved Lubrication ◽  
Piston Ring Lubrication ◽  
Cylinder Bore ◽  
Lubrication Conditions

In this paper a mixed lubrication model considering lubricant supply conditions on cylinder bore has been developed for the piston ring lubrication. The numerical procedures of both fully flooded and starved lubrication were included in the model. The lubrication equations and boundary conditions at the end of strokes were discussed in detail. The effects of piston ring design parameters, such as ring face profile and ring tension, on oil film thickness, friction force and power loss under fully flooded and starved lubrication conditions due to available lubricant supply on cylinder bore were studied. The simulation results show that the oil available in the inlet region of the oil film is important to the piston ring friction power loss. With different ring face crown heights and tensions, the changes of oil film thickness and friction force were apparent under fully flooded lubrication, but almost no changes were found under starved lubrication except at the end of a stroke. In addition, the oil film thickness and friction force were affected evidently by the ring face profile offsets under both fully flooded and starved lubrication conditions, and the offset towards the combustion chamber made a large contribution to forming thicker oil film during the expansion stroke. So under different lubricant supply conditions on the cylinder bore, the ring profile and tension need to be adjusted to reduce the friction and power loss. Moreover, the effects of lubricant viscosity, surface composite roughness, and engine operating speed on friction force and power loss were also discussed.

A comprehensive mathematical model for an accurate calculation of the oil film thickness of strip cold rolling

2019 ◽  
Vol 234 (3) ◽  
pp. 350-361
Author(s):  
Xinxiao Bian ◽  
Quan Wang
Keyword(s):  
Mathematical Model ◽  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Rolling Force ◽  
Elastohydrodynamic Lubrication ◽  
Rolled Strip ◽  
Asperity Contact ◽  
Oil Film ◽  
Rolling Oil ◽  
Lubricant Viscosity

The surface quality of cold rolled strip is related to a greater extent on the rolling oil film thickness, and there are many factors that affect the oil film thickness. Considering the various factors comprehensively, an integrated mathematical model is established, such as roughness of rolls and strips, elastohydrodynamic lubrication, friction heat and plastic deformation heat in the rolling zone, viscosity varying with temperature and pressure, etc. A series of equations are developed, such as the Reynolds equation of partial membrane hydrodynamic lubrication based on average flow theory, equation of oil film thickness on rough elastic surface, the thermal interface equations between strip, oil film and roller surface, surface asperity contact pressure equation, lubricant viscosity and density equations, motion equation of the oil film, etc. This model is solved by finite difference method to get the film pressure, oil film thickness, and temperature distribution in the rolling zone. The average rolling pressure, the roll, and strip temperature calculated by the model are very close to the field test results. Comparing the minimum film thickness calculated by the model with the regression formula of other literature test, the error is less than 10%. The minimum oil film thickness is analyzed. It increases with the decrease of the rolling force and is approximately proportional to the rolling speed and lubricant viscosity.

A Simulation of Hydrodynamic Lubrication on Non-Glazed Surfaces under Different Sliding Velocities and Loads

2007 ◽  
Vol 353-358 ◽  
pp. 827-830
Author(s):  
Peng Li ◽  
Jian Li ◽  
Yong Zhen Zhang ◽  
M. Scherge
Keyword(s):  
Wear Resistance ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Hydrodynamic Lubrication ◽  
Maximum Pressure ◽  
Minimum Film Thickness ◽  
Pin On Disk ◽  
Lubrication Conditions

Recent researches have found that surfaces with non-glazed or laser dimpling topography offer improved lubricating efficiency and wear resistance under lubrication conditions over their conventional glazed status. It was carried out in this paper to simulate a pin-on-disk experimental condition and perform hydrodynamic lubrication (HL) calculations for both non-glazed and glazed surfaces under conditions of different sliding velocities and loads with a view of understanding the tribological mechanism and characteristics of non-glazed surfaces. The results showed that the minimum film thickness of non-glazed surfaces, which closed to a typical elasto-hydrodynamic lubrication (EHL) film thickness, was thicker than that of glazed surfaces under the condition of low sliding velocities and small loads. At the same time, a decreased maximum pressure of full-film of non-glazed surfaces demonstrated an even pressure distribution on them.

Application of dynamic mesh technology in the oil film flow simulation for hydrostatic bearing

2019 ◽  
Vol 71 (1) ◽  
pp. 146-153
Author(s):  
Yanqin Zhang ◽  
Zhiquan Zhang ◽  
Xiangbin Kong ◽  
Rui Li ◽  
Hui Jiang
Keyword(s):  
Film Thickness ◽  
Flow Velocity ◽  
Manufacturing Industry ◽  
Dynamic Mesh ◽  
Lubricating Oil ◽  
Thickness Variation ◽  
Content Type ◽  
Oil Film ◽  
Rotating Speed ◽  
Hydrostatic Bearing

Purpose The purpose of this paper was to obtain the lubrication characteristics of heavy hydrostatic bearing in heavy equipment manufacturing industry through theoretical analysis and numerical simulation. Design/methodology/approach This paper discusses the influence of oil film thickness variation on velocity field, outlet-L and outlet-R flow velocity under the hydrostatic bearing running in no-load 0 N, load 400 KN, full load 1,500 KN and rotating speeds of 10 r/min, 20 r/min, 30 r/min, 40 r/min, 50 r/min and 60 r/min, by using dynamic mesh technology and FLUENT software. Findings When the working table rotates clockwise, in the change process of oil film thickness, the fluid flow pattern of the lubricating oil at the edge of the sealing oil is the rule of laminar flow, and the oil cavity has a vortex. The outlet-R flow velocity becomes higher and higher by increasing the bearing load and working table speed, and the flow velocity increases with the decrease in oil film thickness; the outlet-L flow velocity increases with the decrease in oil film thickness under low rotating speed (less than 10 r/min) condition and decreases with the decrease of oil film thickness under high rotating speed (more than 60 r/min) condition. Originality/value The influence of the oil film thickness on the flow state distribution of the oil film was analyzed under different working conditions, and the influence rules of oil film thickness on the flow velocity of hydrostatic bearing oil pad was obtained by using dynamic mesh technology.

Study of Hybrid Lubrication at the Tooth Contact of a Wormgear Transmission: Part 2—Results and Discussion

1998 ◽  
Vol 120 (1) ◽  
pp. 112-118
Author(s):  
Qin Yuan ◽  
D. C. Sun ◽  
D. E. Brewe
Keyword(s):  
Temperature Distribution ◽  
Film Thickness ◽  
Numerical Solution ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Power Loss ◽  
Oil Film ◽  
Supply Pressure ◽  
Transmission Part

Part 2 begins by describing the numerical solution procedures of the hybrid lubrication problem. Results of the computation are then presented that include the detailed pressure and temperature distribution in the oil film, the required supply pressure for maintaining the prescribed minimum oil film thickness, the fluid friction acting on the worm coil surface, the mass flow rate of supply oil, and the power loss associated with the restrictor flow. The feasibility of the hydrostatically lubricated wormgear transmission is discussed in light of these results.

The Influence of Gear Parameters on Oil Film Thickness of Tooth Surface

2011 ◽  
Vol 79 ◽  
pp. 293-297
Author(s):  
Li Hong Liu ◽  
Zhan Ni Li ◽  
Han Bing Cao
Keyword(s):  
Film Thickness ◽  
Hydrodynamic Lubrication ◽  
Gear Ratio ◽  
Tooth Surface ◽  
Speed Ratio ◽  
Oil Film ◽  
Single Tooth ◽  
Hydrodynamic Lubrication Theory ◽  
Tooth Flank ◽  
Center Distance

Applying elastic-hydrodynamic lubrication theory, oil film thickness of tooth surface was studies in accordance with the quasi-steady state. This paper focused on the influence of gear parameters such as gear ratio, module and center distance on the thickness of oil film of tooth flank. The results show, as speed ratio increases, oil film thickness increases significantly. When the number of teeth is fixed, oil film thickness increases significantly with the increase of module. When center distance is fixed, oil film thickness declines greatly with the increase of module in both into meshing and out of meshing points. Therefore when center distance is fixed, less module and more teeth are selected，on the condition that gear intensity is met. By results analyzing, the minimal oil film thickness may occur in the single tooth meshing area and into meshing or out of meshing points.

Further Experiments on the Sealing Mechanism of a Synthetic Rubber Lip Type Seal Operating on a Rotating Shaft

1973 ◽  
Vol 187 (1) ◽  
pp. 361-367 ◽  
Author(s):  
E. T. Jagger ◽  
D. Wallace
Keyword(s):  
Surface Tension ◽  
Film Thickness ◽  
Liquid Film ◽  
Hydrodynamic Lubrication ◽  
Contact Angles ◽  
Rotating Shaft ◽  
Synthetic Rubber ◽  
Sealing Mechanism ◽  
Inside Out ◽  
Lubrication Conditions

The paper shows that a seal of the type referred to operates under hydrodynamic lubrication conditions with a liquid film thickness of obout 0·5 μm. Contact angles of oil against rubber and steel are measured, and it is also shown by experiments with capillaries how a meniscus may be turned inside out to resist pressure. The conclusion is that the liquid film is prevented from leaking by the surface tension of the liquid itself.

A Performance Prediction of Microgrooved Bearings Under Mixed Lubrication

2008 ◽  
Author(s):  
Katsuhiro Ashihara ◽  
Hiromu Hashimoto
Keyword(s):  
Film Thickness ◽  
Contact Pressure ◽  
Hydrodynamic Lubrication ◽  
Calculation Model ◽  
Mixed Lubrication ◽  
Severe Condition ◽  
Oil Film ◽  
Precise Prediction ◽  
Lubrication Condition ◽  
Bearing Alloy

In the designs and analysis of engine bearings for automobiles, the precise prediction of the lubrication condition in severe condition is important. In the mixed-elasto-hydrodynamic lubrication analysis, the contact between the projections of surface roughness distributed stochastically is usually considered. This paper describes a theoretical model under the mixed lubrication in the microgrooved bearing. In this modeling, it is assumed that the section shape of microgrooved bearing alloy takes the circular arc form. In the part where contact is caused, the contact pressure is calculated by the Hertzian equation. The elastic deformation of the bearing by the mixed pressure with which oil film pressure and contact pressure are mixed by each allotment ratio is considered. Moreover, the balance requirement between the sum total of mixed pressure on bearing surface and the journal load is met. Under such an assumption, the numerical calculation model is newly obtained to predict the bearing performance in the mixed lubrication of microgrooved bearing. The numeric solutions of EHL based on the mixed lubrication are compared with EHL based on the fluid lubrication. The predicted oil film thickness at the center of bearing by the mixed lubrication model is remarkably thin compared with that by the fluid lubrication model. This shows that the load ability of the oil film thickness decreases by generating contact.

Numerical Simulation on the Lubrication Performance of Surface Textured Piston Rings

2011 ◽  
Vol 199-200 ◽  
pp. 734-738 ◽  
Author(s):  
Qiu Ying Chang ◽  
Xian Liang Zheng ◽  
Qing Liu
Keyword(s):  
Numerical Simulation ◽  
Film Thickness ◽  
Friction Force ◽  
Friction And Wear ◽  
Piston Ring ◽  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Area Density ◽  
Oil Film ◽  
Lubrication Performance

Surface texturing has been successfully employed in some tribological applications in order to diminish friction and wear. This technology may be used in a piston ring to decrease the friction and wear of the contact between a piston ring and cylinder liner. A numerical simulation of lubrication between a surface textured piston ring and cylinder liner based on the hydrodynamic lubrication theory was conducted. The influence of surface texture parameters on piston ring lubrication performance was obtained by solving the mathematical equations with a multi-grid method. The results show that under the micro-dimple area density of 5%-40% the minimum oil film thickness increases and the dimensionless friction force decreases with the increasing of it. Under the dimple area density of 40%-60%, the minimum oil film thickness and the dimensionless friction force change slightly. Under various dimple area densities the optimum dimple depth at the given working condition in this paper is about 5µm.

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