Sliding Wear Calculation in Spur Gears

1993 ◽  
Vol 115 (3) ◽  
pp. 493-500 ◽  
Author(s):  
Shifeng Wu ◽  
H. S. Cheng
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Elastohydrodynamic Lubrication ◽  
Tooth Wear ◽  
Spur Gears ◽  
Gear Teeth ◽  
Tooth Surfaces ◽  
Wear Calculation ◽  
Determining Factor ◽  
Wear Region

In gear applications where precipitous tooth failure mode such as scoring or scuffing has been avoided, “normal” wear becomes a life-determining factor. In this paper, sliding wear in spur gears, including the considerations of gear dynamics and rough-elastohydrodynamic lubrication, is analyzed. Formulas for equivalent wear rate and tooth wear profile along the line of action are derived. Results show that most materials are removed from both the addendum and dedendum tooth surfaces, and that the highest wear occurs at the beginning of an engagement. This high wear region corresponds to the root of the driving (pinion) teeth and the tip of the driven (gear) teeth. These analytical results correlate well with the practical evidences in AGMA documentation.

Effect of profile modification on the performance of spur gears in isothermal mixed-EHL regime using load-sharing concept

2018 ◽  
Vol 233 (6) ◽  
pp. 936-948 ◽  
Author(s):  
Masoud Kimiaei ◽  
Saleh Akbarzadeh
Keyword(s):  
Wear Rate ◽  
Power Transmission ◽  
Elastohydrodynamic Lubrication ◽  
Load Sharing ◽  
Spur Gears ◽  
Gear Teeth ◽  
Profile Modification ◽  
Model Based ◽  
Mechanical Element ◽  
The Cost

Spur gears are one of the most important tools for power transmission in the industry and thus can be considered a key mechanical element. As a result of power transmission, gears might fail or experience wear and fatigue. So the improvement in the design and modification of tooth profile of gears can significantly reduce friction loss and wear of the gear teeth and therefore it increases the useful life, improves the quality, and reduces the cost. The purpose of this study is to show the influence of addendum modification on the tribological performance of spur gears which are operating in the mixed elastohydrodynamic lubrication. In this paper, a model based on the load-sharing concept is employed to study the effect of changing addendum modification on the performance of spur gears, the amount of wear rate, and the lubricant film thickness. To this end, a model based on the load-sharing concept is employed which takes the geometry and lubricant properties as input and predicts the friction coefficient, load carried by fluid film and asperities, efficiency, and wear rate as output.

Prediction of Steady State Adhesive Wear in Spur Gears Using the EHL Load Sharing Concept

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
S. Akbarzadeh ◽  
M. M. Khonsari
Keyword(s):  
Steady State ◽  
Wear Rate ◽  
Thermal Effects ◽  
Sliding Wear ◽  
Adhesive Wear ◽  
Load Sharing ◽  
Spur Gears ◽  
Wear Model ◽  
Wear Calculation ◽  
Simulation Results

The concept of load sharing between asperities and fluid film is applied in conjunction with lubricated sliding wear formulation proposed by Wu and Cheng (1991, “A Sliding Wear Model for Partial-EHL Contacts,” ASME J. Tribol., 113, pp. 134–141; 1993, “Sliding Wear Calculation in Spur Gears,” ASME J. Tribol., 115, pp. 493–500) to predict the steady state adhesive wear in gears. Thermal effects are included using a simplified thermoelastohydrodynamic analysis. The prediction of the model is verified by comparing simulation results with published experimental data pertinent to steady state wear rate. The main advantages of this method are the accuracy and the remarkable computational efficiency. The results of parametric simulation study are presented to investigate the effect of speed and surface roughness on a portion of load carried by asperities and wear rate.

Analysis of the dynamic contact between rotating spur gears by finite element and multi-body dynamics techniques

2001 ◽  
Vol 215 (4) ◽  
pp. 423-435 ◽  
Author(s):  
K Lee
Keyword(s):  
Finite Element ◽  
Contact Point ◽  
Equations Of Motion ◽  
Mass Effect ◽  
Dynamic Contact ◽  
Spur Gears ◽  
Gear Teeth ◽  
Body Dynamics ◽  
Tooth Surfaces ◽  
Multi Body

A numerical method is presented for the dynamic contact analysis of spur gears rotating with very high angular speeds. For each gear an elastic tooth of distributed mass is connected to a rigid disc with kinematic constraints, and finite element formulations are used for the equations of motion of the teeth. The velocity and acceleration as well as the position of the contact point sliding on the mating gear teeth are precisely computed by simultaneously using the motions of a pair of rotating tooth surfaces. The equations of motion subjected to the kinematic constraint and contact condition are solved by enforcing the velocity and acceleration constraints as well as the displacement constraint. In the numerical simulation the importance of the mass effect of gear teeth is demonstrated, and it is shown that the solution is obtained even if gears repeat contact and separation.

scholarly journals Elastohydrodynamic Lubrication Analysis of Gear Tooth Surfaces From Micropitting Tests

2003 ◽  
Vol 125 (2) ◽  
pp. 267-274 ◽  
Author(s):  
J. Tao ◽  
T. G. Hughes ◽  
H. P. Evans ◽  
R. W. Snidle ◽  
N. A. Hopkinson ◽  
...  
Keyword(s):  
Film Thickness ◽  
Gear Tooth ◽  
Testing Machine ◽  
Elastohydrodynamic Lubrication ◽  
Real Surface ◽  
Test Protocol ◽  
Contact Phase ◽  
Gear Teeth ◽  
Pressure Cycling ◽  
Tooth Surfaces

The paper presents numerical results for the elastohydrodynamic lubrication of gear teeth using real surface roughness data taken from micropitting tests carried out on an FZG gear testing machine. Profiles and load conditions corresponding to four load stages in the micropitting test protocol are considered. Elastohydrodynamic film thickness and pressure analyses are presented for conditions having a slide/roll ratio of 0.3 during the single tooth contact phase of the meshing cycle. Comparisons are also included showing the elastohydrodynamic response of the tooth contacts at different times in the meshing cycle for one of the load stages. The rheological model adopted is based on Ree-Eyring non-Newtonian shear thinning, and comparisons are also included of models having constant and different pressure-dependent specifications of the Eyring shear stress parameter τ0. Parameters obtained from the micro EHL analyses are presented that quantify the degree of adversity experienced by the surfaces in elastohydrodynamic contact. These quantify extreme pressure behavior, extreme proximity of surfaces, and pressure cycling within the overall contact and indicate that the different fluid models considered lead to significantly different pressure and film thickness behavior within the contact.

Gear lubrication—a review

2002 ◽  
Vol 216 (5) ◽  
pp. 255-267 ◽  
Author(s):  
A. V. Olver
Keyword(s):  
Current Practice ◽  
Elastohydrodynamic Lubrication ◽  
Simple Calculation ◽  
Theoretical Research ◽  
Spur Gears ◽  
Simple Estimate ◽  
Gear Teeth ◽  
Lubricating Film ◽  
Smooth Body ◽  
Key Aspects

The lubrication of gear teeth is reviewed including some key aspects of recent theoretical research and current practice. A simple estimate of the thickness of the lubricating film in a typical pair of spur gears is presented on the basis of classical smooth-body isothermal, elastohydrodynamic lubrication theory. The deficiencies of this simple calculation are then discussed; these include roughness, friction, churning, starvation and contamination, all common features of practical gearing. Three simple methods are described for estimating the tooth temperature and its consequent effect on film thickness.

A Novel Method for Calculation Gear Tooth Stiffness for Dynamic Analysis of Spur Gears With Asymmetric Teeth

2014 ◽  
Author(s):  
F. Karpat ◽  
O. Dogan ◽  
S. Ekwaro-Osire ◽  
C. Yuce
Keyword(s):  
Gear Tooth ◽  
Load Capacity ◽  
Operating Conditions ◽  
Spur Gears ◽  
Finite Elements Analysis ◽  
Gear Teeth ◽  
Research Activities ◽  
Tooth Surfaces ◽  
Tooth Stiffness ◽  
Tooth Flank

Recently, there have been a number of research activities on spur gears with asymmetric teeth. The benefits of asymmetric gears are: higher load capacity, reduced bending and contact stress, lower weight, lower dynamic loads, reduced wear depths on tooth flank, higher reliability, and higher efficiency. Each of the benefits can be obtained through asymmetric teeth designed correctly. Gears operate in several conditions, such as inappropriate lubrication, excessive loads and installation problems. In working conditions, damage can occur in tooth surfaces due to excessive loads and unsuitable operating conditions. One of the important parameters of the tooth is stiffness, which is found to be reduced proportionally to the severity of the defect by asymmetric tooth design as described in this paper. The estimation of gear stiffness is an important parameter for determining loads between the gear teeth when two sets of teeth are in contact. In this paper, a 2-D tooth model is developed for finite elements analysis. A novel formula is derived from finite element results in order to estimate tooth stiffness depending on the tooth number and pressure angle on the drive side. Tooth stiffness for spur gears with asymmetric teeth is calculated and the results were compared with well known equations in literature.

scholarly journals Sliding Wear of Conventional and Suspension Sprayed Nanocomposite WC-Co Coatings: An Invited Review

2021 ◽  
Author(s):  
R. Ahmed ◽  
O. Ali ◽  
C. C. Berndt ◽  
A. Fardan
Keyword(s):  
Wear Rate ◽  
Thermal Spray ◽  
Sliding Wear ◽  
Failure Modes ◽  
Thermal Spray Coatings ◽  
Annual Growth Rate ◽  
Total Energy Consumption ◽  
Wear Performance ◽  
Wear Rates ◽  
Spray Coatings

AbstractThe global thermal spray coatings market was valued at USD 10.1 billion in 2019 and is expected to grow at a compound annual growth rate of 3.9% from 2020 to 2027. Carbide coatings form an essential segment of this market and provide cost-effective and environmental friendly tribological solutions for applications in aerospace, industrial gas turbine, automotive, printing, oil and gas, steel, and pulp and paper industries. Almost 23% of the world’s total energy consumption originates from tribological contacts. Thermal spray WC-Co coatings provide excellent wear resistance for industrial applications in sliding and rolling contacts. Some of these applications in abrasive, sliding and erosive conditions include sink rolls in zinc pots, conveyor screws, pump housings, impeller shafts, aircraft flap tracks, cam followers and expansion joints. These coatings are considered as a replacement of the hazardous chrome plating for tribological applications. The microstructure of thermal spray coatings is however complex, and the wear mechanisms and wear rates vary significantly when compared to cemented WC-Co carbides or vapour deposition WC coatings. This paper provides an expert review of the tribological considerations that dictate the sliding wear performance of thermal spray WC-Co coatings. Structure–property relationships and failure modes are discussed to grasp the design aspects of WC-Co coatings for tribological applications. Recent developments of suspension sprayed nanocomposite coatings are compared with conventional coatings in terms of performance and failure mechanisms. The dependency of coating microstructure, binder material, carbide size, fracture toughness, post-treatment and hardness on sliding wear performance and test methodology is discussed. Semiempirical mathematical models of wear rate related to the influence of tribological test conditions and coating characteristics are analysed for sliding contacts. Finally, advances for numerical modelling of sliding wear rate are discussed.

scholarly journals Influence of Test Conditions on Sliding Wear Performance of High Velocity Air Fuel-Sprayed WC–CoCr Coatings

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3074
Author(s):  
Kaveh Torkashvand ◽  
Vinod Krishna Selpol ◽  
Mohit Gupta ◽  
Shrikant Joshi
Keyword(s):  
Wear Rate ◽  
Test Performance ◽  
Sliding Wear ◽  
Normal Load ◽  
Specific Wear Rate ◽  
Wear Behaviour ◽  
Wear Performance ◽  
Test Conditions ◽  
Test Parameters ◽  
Sliding Distance

Sliding wear performance of thermal spray WC-based coatings has been widely studied. However, there is no systematic investigation on the influence of test conditions on wear behaviour of these coatings. In order to have a good understanding of the effect of test parameters on sliding wear test performance of HVAF-sprayed WC–CoCr coatings, ball-on-disc tests were conducted under varying test conditions, including different angular velocities, loads and sliding distances. Under normal load of 20 N and sliding distance of 5 km (used as ‘reference’ conditions), it was shown that, despite changes in angular velocity (from 1333 rpm up to 2400 rpm), specific wear rate values experienced no major variation. No major change was observed in specific wear rate values even upon increasing the load from 20 N to 40 N and sliding distance from 5 km to 10 km, and no significant change was noted in the prevailing wear mechanism, either. Results suggest that no dramatic changes in applicable wear regime occur over the window of test parameters investigated. Consequently, the findings of this study inspire confidence in utilizing test conditions within the above range to rank different WC-based coatings.

The Compliance of Solid, Wide-Faced Spur Gears

1990 ◽  
Vol 112 (4) ◽  
pp. 590-595 ◽  
Author(s):  
J. H. Steward
Keyword(s):  
Experimental Data ◽  
Contact Line ◽  
Load Distribution ◽  
3D Model ◽  
Spur Gear ◽  
Point Load ◽  
Spur Gears ◽  
Line Load ◽  
Gear Teeth ◽  
Theoretical Results

In this paper, the requirements for an accurate 3D model of the tooth contact-line load distribution in real spur gears are summarized. The theoretical results (obtained by F.E.M.) for the point load compliance of wide-faced spur gear teeth are set out. These values compare well with experimental data obtained from tests on a large spur gear (18 mm module, 18 teeth).

A study on tribological behaviour and analysis of ZnO reinforced AA6061 matrix composites fabricated by stir casting route

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sakthi Sadhasivam RM ◽  
Ramanathan K. ◽  
Bhuvaneswari B.V. ◽  
Raja R.
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Stir Casting ◽  
Industrial Applications ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Tribological Behaviour ◽  
Content Type ◽  
Zno Particles ◽  
The Matrix

Purpose The most promising replacements for the industrial applications are particle reinforced metal matrix composites because of their good and combined mechanical properties. Currently, the need of matrix materials for industrial applications is widely satisfied by aluminium alloys. The purpose of this paper is to evaluate the tribological behaviour of the zinc oxide (ZnO) particles reinforced AA6061 composites prepared by stir casting route. Design/methodology/approach In this study, AA6061 aluminium alloy matrix reinforced with varying weight percentages (3%, 4.5% and 6%) of ZnO particles, including monolithic AA6061 alloy samples, is cast by the most economical fabrication method, called stir casting. The prepared sample was subjected to X-ray photoelectron spectroscopy (XPS) analysis, experimental density measurement by Archimedian principle and theoretical density by rule of mixture and hardness test to investigate mechanical property. The dry sliding wear behaviour of the composites was investigated using pin-on-disc tribometer with various applied loads of 15 and 20 N, with constant sliding velocity and distance. The wear rate, coefficient of friction (COF) and worn surfaces of the composite specimens and their effects were also investigated in this work. Findings XPS results confirm the homogeneous distribution of ZnO microparticles in the Al matrix. The Vickers hardness result reveals that higher ZnO reinforced (6%) sample have 34.4% higher values of HV than the monolithic aluminium sample. The sliding wear tests similarly show that increasing the weight percentage of ZnO particles leads to a reduced wear rate and COF of 30.01% and 26.32% lower than unreinforced alloy for 15 N and 36.35% and 25% for 20 N applied load. From the worn surface morphological studies, it was evidently noticed that ZnO particles dispersed throughout the matrix and it had strong bonding between the reinforcement and the matrix, which significantly reduced the plastic deformation of the surfaces. Originality/value The uniqueness of this work is to use the reinforcement of ZnO particles with AA6061 matrix and preparing by stir casting route and to study and analyse the physical, hardness and tribological behaviour of the composite materials.

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