scholarly journals An Improved Algorithm for Calculating Friction Force and Torque in Involute Helical Gears

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Lin Han ◽  
Wentie Niu ◽  
Dawei Zhang ◽  
Fujun Wang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Load Distribution ◽  
Distribution Model ◽  
Contact Lines ◽  
Helical Gears ◽  
Constant Friction ◽  
Single Tooth ◽  
The Difference ◽  
Typical Design

Time varying frictional force and torque are one of the main exciting sources of vibration in helical gears. This paper presents an approach to determine the friction force and torque in involute helical gears considering nonuniform load distribution along contact lines. An analytical load distribution model is employed and extended to obtain the load per unit of length along contact lines. Friction force and torque models under nonuniform assumption are derived. Comparisons of the determined friction force and torque with the results from uniform assumption are made. In addition, the differences between constant friction coefficient and varying coefficient are revealed. Moreover, two typical design cases of helical gears are studied. Results show that the fluctuations of friction force and torque under uniform assumption are more significant than those under nonuniform assumption in sample I for a single tooth, but less significant for the sum of those of the three teeth, while in sample II, the fluctuations under uniform assumption are less significant than those under nonuniform assumption. The friction coefficient induced difference is negligible compared with the difference induced by load distribution assumptions.

An experimental study on the cryogenic face seal at different inlet pressures

2019 ◽  
Vol 234 (9) ◽  
pp. 1470-1481
Author(s):  
Guoyuan Zhang ◽  
Yangyang Zhao ◽  
Weigang Zhao ◽  
Xiutian Yan ◽  
Maotan Liang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
High Speed ◽  
Fluid Pressure ◽  
Stable State ◽  
Test System ◽  
Leakage Rate ◽  
Mechanical Seals ◽  
Closing Force ◽  
The Difference

An experimental test system for cryogenic high-speed hydrodynamic non-contact mechanical seals is developed. Based on this system, the performances of seals under different working conditions are studied in detail in this paper. With the experimental results, the main performances of the seals (such as inlet and outlet temperatures, separated speed, face temperature, friction force, friction coefficient, leakage rate) are obtained, and the relationships of the performances with the inlet fluid pressure, the closing force and the rotational speed are discussed. The results show that the difference between the outlet and inlet temperatures decreases with increasing inlet fluid pressure. As the speed increases, the friction force varies little and remains at a constant value. The friction coefficient of the seal is approximately 0.12 and basically does not change with the speed. The leakage rate is also maintained at approximately 190 g/s. With the increase in the closing force, the friction at the seal’s face does not change greatly, which indicates that the friction at the face is always in a stable state with the seal’s closing force.

Stress analysis of coated spur and helical gears considering load distribution

2020 ◽  
Vol 234 (5) ◽  
pp. 649-667
Author(s):  
Yong Yang ◽  
Jiaxu Wang ◽  
Yanyan Huang ◽  
Wanyou Yang ◽  
Qinghua Zhou
Keyword(s):  
Friction Coefficient ◽  
Critical Load ◽  
Coating Thickness ◽  
Load Distribution ◽  
Sliding Friction ◽  
Load Condition ◽  
Elastic Field ◽  
Distribution Model ◽  
Stress Distributions ◽  
Influence Coefficients

A load distribution model along the line of contact considering sliding friction is proposed for both spur and helical gear pairs in order to determine the critical load condition. Further, a semi-analytical method is introduced for modeling the stress field of coated gears. The elastic field is calculated by utilizing influence coefficients obtained from frequency response functions and discrete convolution and fast Fourier transform. Effects of friction coefficient, coating properties and thickness on the stress distribution of a gear pair at the critical load position during meshing are investigated. Maps describing the maximum transverse and shear stress distributions on coating–substrate interface with respect to friction coefficient and coating thickness are demonstrated, which may facilitate the selection of preferable coating thickness.

Effects of Tooth Indexing Errors on Load Distribution and Tooth Load Sharing of Splines Under Combined Loading Conditions

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
J. Hong ◽  
D. Talbot ◽  
A. Kahraman
Keyword(s):  
Load Distribution ◽  
Probability Distributions ◽  
Random Sequence ◽  
Load Sharing ◽  
Spur Gear ◽  
Combined Loading ◽  
Distribution Model ◽  
Loading Conditions ◽  
Manufacturing Tolerance ◽  
Single Tooth

In this paper, influences of tooth indexing errors on load distribution and tooth load sharing of spline joints are investigated by modifying an existing semi-analytical load distribution model for side-fit involute splines. Two commonly observed loading conditions, namely (i) combined torsion and radial loads representative of a spline joint of a spur gear with shaft and (ii) combined torsion, radial loads, and tilting moment representative of a spline joint of a helical gear with shaft are considered in this study. Numerical results of an example spline having (i) no tooth indexing error, (ii) a single tooth with indexing error, and (iii) a random sequence of tooth indexing errors under these two loading conditions are presented to demonstrate the effects of tooth indexing errors. In addition, a practical study of the robustness to manufacturing tolerances is also presented where probability distributions of load sharing factor of the critical tooth of an example spline designed to certain manufacturing tolerance classes are obtained with a large number of randomly generated indexing error sequences.

Solution of Load Distribution on the Contact Line of Helical Gears With EHL Theory

1994 ◽  
Author(s):  
Yu Tonghui ◽  
Chen Chenwen ◽  
Wang Liqin
Keyword(s):  
Contact Line ◽  
Load Distribution ◽  
Multigrid Method ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Elastohydrodynamic Lubrication ◽  
Helical Gear ◽  
Contact Lines ◽  
Helical Gears ◽  
Special Boundary Condition

Abstract On the base of analysis of the effects of each term in Renolds equaiton on the lubrication state of helical gears, the three dimensional elastohydrodynamic lubrication (EHL) problem is discomposed into two dimensional problems to deal with. A special boundary condition for helical gear EHL problem is led in and applying multigrid method (MGM), numerical solutions for the helical gear EHL problem are accomplished along the contact line. Film shapes and pressure ditributions with typical EHL features are obtained at discreted points on the contact line. The procedure presented here to calculate the load distribution on the contact line can also be used to calculate the load shares among different contact lines.

Load Distribution Model for Involute Internal Gear Sets

2007 ◽  
Author(s):  
Jose´ I. Pedrero ◽  
Miguel Pleguezuelos ◽  
Silvia Aguiriano
Keyword(s):  
Contact Stress ◽  
Load Distribution ◽  
Elastic Potential ◽  
Distribution Model ◽  
Uniform Load ◽  
Helical Gears ◽  
New Model ◽  
Gear Drives ◽  
Internal Gear ◽  
Load Conditions

This paper presents a new model of load distribution for involute, internal gear drives, which takes into account the changing rigidity of the pair of teeth along the path of contact. The model has been obtained from the minimum elastic potential criterion, resulting in a non-uniform load distribution along the line of contact (for helical gears), as well as among several pairs in simultaneous contact. A study of the nominal contact stress, including the calculation of the determinant load conditions, is also presented.

Effect of shape/size and distribution of microgeometries of textures on tribo-performance of crankpin bearing

2021 ◽  
pp. 135065012110105
Author(s):  
Nguyen Van Liem ◽  
Wu Zhenpeng ◽  
Jiao Renqiang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Contact Force ◽  
Distribution Density ◽  
Hydrodynamic Lubrication ◽  
Operating Conditions ◽  
Asperity Contact ◽  
Combined Model ◽  
Obvious Effect ◽  
Area Density

The effect of the shape/size and distribution of microgeometries of textures on improving the tribo-performance of crankpin bearing is proposed. Based on a combined model of the slider-crank mechanism dynamic and hydrodynamic lubrication, the distribution density, area density, and shape of spherical textures, square-cylindrical textures, wedge-shaped textures, and a hybrid between spherical texture and square-cylindrical texture on the crankpin bearing's tribo-performance are investigated under different operating conditions of the engine. The tribological characteristic of the crankpin bearing is then evaluated via the indexes of the oil film pressure p, asperity contact force, friction force, and friction coefficient of the crankpin bearing. The research results show that the distribution density with n = 12 and m = 6, and area density with α = 30% of various microtextures have an obvious effect on ameliorating the crankpin bearings tribo-performance. Concurrently, at the mixed lubrication region, the shape of the square-cylindrical texture on improving the tribo-performance is better than the other shapes of the spherical texture, wedge-shaped texture, and spherical and square-cylindrical texture. Particularly, all the average values of the asperity contact force, friction force, and friction coefficient with a square-cylindrical texture are significantly reduced by 14.6%, 19.5%, and 34.5%, respectively, in comparison without microtextures. Therefore, the microtextures of the spherical texture applied on the bearing surface can contribute to enhance the durability and decrease the friction power loss of the engine.

scholarly journals The Effect of Co-Deposition of SiC Sub-Micron Particles and Heat Treatment on Wear Behaviour of Ni–P Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Donya Ahmadkhaniha ◽  
Lucia Lattanzi ◽  
Fabio Bonora ◽  
Annalisa Fortini ◽  
Mattia Merlin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Wear Mechanisms ◽  
Composite Coatings ◽  
Wear Behaviour ◽  
Maximum Hardness ◽  
Sic Particles ◽  
Heat Treated ◽  
The Coefficient Of Friction ◽  
The Difference

The purpose of the study is to assess the influence of SiC particles and heat treatment on the wear behaviour of Ni–P coatings when in contact with a 100Cr6 steel. Addition of reinforcing particles and heat treatment are two common methods to increase Ni–P hardness. Ball-on-disc wear tests coupled with SEM investigations were used to compare as-plated and heat-treated coatings, both pure and composite ones, and to evaluate the wear mechanisms. In the as-plated coatings, the presence of SiC particles determined higher friction coefficient and wear rate than the pure Ni–P coatings, despite the limited increase in hardness, of about 15%. The effect of SiC particles was shown in combination with heat treatment. The maximum hardness in pure Ni–P coating was achieved by heating at 400 °C for 1 h while for composite coatings heating for 2 h at 360 °C was sufficient to obtain the maximum hardness. The difference between the friction coefficient of composite and pure coatings was disclosed by heating at 300 °C for 2 h. In other cases, the coefficient of friction (COF) stabilised at similar values. The wear mechanisms involved were mainly abrasion and tribo-oxidation, with the formation of lubricant Fe oxides produced at the counterpart.

A novel technique for modeling friction behavior in knitted fabric simulation

2017 ◽  
Vol 29 (6) ◽  
pp. 776-792
Author(s):  
Vajiha Mozafary ◽  
Pedram Payvandy
Keyword(s):  
Friction Coefficient ◽  
Uniform Distribution ◽  
Friction Force ◽  
Experimental Result ◽  
Knitted Fabric ◽  
Friction Behavior ◽  
Content Type ◽  
Novel Technique ◽  
Fabric Structure ◽  
Fabric Surface

Purpose Fabric-object friction force is a fundamental factor in cloth simulation. A large number of parameters influence the frictional properties of fabrics such as fabric structure, yarn structure, and inherent properties of component fibers. The purpose of this paper is to propose a novel technique for modeling fabric-object friction force in knitted fabric simulation based on the mass spring model. Design/methodology/approach In this technique, unlike other studies, distribution of friction coefficient over the fabric surface is not uniform and depends on the fabric structure. The main reason for considering non-uniform distribution is that in various segments of fabric, contact percent of fabric-object is different. Findings The proposed technique and common methods based on friction coefficient uniform distribution are used to simulate the frictional behavior of knitted fabrics. The results show that simulation error values for proposed technique and common methods are 2.7 and 9.4 percent as compared with the experimental result, respectively. Originality/value In the existing methods of the friction force modeling, the friction coefficient of fabric is assumed uniform. But this assumption is not correct because fabric does not have an isotropic structure. Thus in this study, the friction coefficient distribution is considered based on fabric structure to achieve more of realistic simulations.

Study of Friction Coefficient and Friction Force on Magnetic Abrasive Finishing

2011 ◽  
Vol 675-677 ◽  
pp. 663-666
Author(s):  
Yan Chen ◽  
Akira Shimamoto ◽  
X. Gao ◽  
M.M. Zhang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Magnetic Particles ◽  
Good Effect ◽  
Magnetic Abrasive Finishing ◽  
Abrasive Particles ◽  
Abrasive Finishing ◽  
Alumina Particles ◽  
The Cost ◽  
Grinding Efficiency

In order to enhance grinding efficiency of the magnetic abrasive finishing (MAF) method, we usually use the sinter method or the cementation method to mix the magnetic particles and abrasive particles together. However, the cost is high, and the variety is incomplete. Therefore, with the ferromagnetism to iron particles, the alumina particles and the lipin three kind of material simple mixture participate in the magnetic abrasive finishing which directly polishes, already obtained the good effect through the experiment. This paper analyses and explains the characteristic of the friction coefficient and the friction force on magnetic abrasive finishing according as account and experiment data.

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