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Vilmos Simon - One of the best experts on this subject based on the ideXlab platform.

  • manufacture of optimized face hobbed spiral Bevel Gears on computer numerical control hypoid generator
    Journal of Manufacturing Science and Engineering-transactions of The Asme, 2014
    Co-Authors: Vilmos Simon
    Abstract:

    In this study, a method is proposed for the advanced manufacture of face-hobbed spiral Bevel Gears on CNC hypoid generators with optimized tooth surface geometry. An optimization methodology is applied to systematically define optimal head-cutter geometry and machine tool settings to introduce optimal tooth modifications. The goal of the optimization is to simultaneously minimize tooth contact pressures and angular displacement error of the driven gear (the transmission error). The optimization is based on machine tool setting variation on the cradle-type generator conducted by optimal polynomial functions. An algorithm is developed for the execution of motions on the CNC hypoid generator using the relations on the cradle-type machine. Effectiveness of the method was demonstrated by using a face-hobbed spiral Bevel gear example. Significant reductions in the maximum tooth contact pressure and in the transmission errors were obtained.

  • optimal machine tool settings for the manufacture of face hobbed spiral Bevel Gears
    Journal of Mechanical Design, 2013
    Co-Authors: Vilmos Simon
    Abstract:

    In this study, an optimization methodology is proposed to systematically define the opti-mal head-cutter geometry and machine-tool settings to simultaneously minimize the toothcontact pressure and angular displacement error of the driven gear (the transmissionerror), and to reduce the sensitivity of face-hobbed spiral Bevel Gears to the misalign-ments. The proposed optimization procedure relies heavily on the loaded tooth contactanalysis for the prediction of tooth contact pressure distribution and transmission errorsinfluenced by the misalignments inherent in the gear pair. The load distribution andtransmission error calculation method employed in this study were developed by theauthor of this paper. The targeted optimization problem is a nonlinear constrained opti-mization problem, belonging to the framework of nonlinear programming. In addition,the objective function and the constraints are not available analytically, but they arecomputable, i.e., they exist numerically through the loaded tooth contact analysis. Forthese reasons, a nonderivative method is selected to solve this particular optimizationproblem. That is the reason that the core algorithm of the proposed nonlinear program-ming procedure is based on a direct search method. The Hooke and Jeeves patternsearch method is applied. The effectiveness of this optimization was demonstrated on aface-hobbed spiral Bevel gear example. Drastic reductions in the maximum tooth contactpressure (62%) and in the transmission errors (70%) were obtained.[DOI: 10.1115/1.4027635]

  • design of face hobbed spiral Bevel Gears with reduced maximum tooth contact pressure and transmission errors
    Chinese Journal of Aeronautics, 2013
    Co-Authors: Vilmos Simon
    Abstract:

    Abstract The aim of this study is to define optimal tooth modifications, introduced by appropriately chosen head-cutter geometry and machine tool setting, to simultaneously minimize tooth contact pressure and angular displacement error of the driven gear (transmission error) of face-hobbed spiral Bevel Gears. As a result of these modifications, the gear pair becomes mismatched, and a point contact replaces the theoretical line contact. In the applied loaded tooth contact analysis it is assumed that the point contact under load is spreading over a surface along the whole or part of the “potential” contact line. A computer program was developed to implement the formulation provided above. By using this program the influence of tooth modifications introduced by the variation in machine tool settings and in head cutter data on load and pressure distributions, transmission errors, and fillet stresses is investigated and discussed. The correlation between the ease-off obtained by pinion tooth modifications and the corresponding tooth contact pressure distribution is investigated and the obtained results are presented.

  • influence of tooth modifications on tooth contact in face hobbed spiral Bevel Gears
    Mechanism and Machine Theory, 2011
    Co-Authors: Vilmos Simon
    Abstract:

    Abstract In this study the influence of tooth modifications induced by machine tool setting and head-cutter profile variations on tooth contact characteristics in face-hobbed spiral Bevel Gears is investigated. The concept of face-hobbed spiral Bevel gear generation by an imaginary generating crown gear is applied. The modifications of tooth surfaces are introduced into the teeth of both members. The lengthwise crowning of teeth is achieved by applying a slightly bigger radius of lengthwise tooth flank curvature of the crown gear generating the concave side of pinion/gear tooth-surfaces, and by the variation of machine tool settings in the generation of pinion/gear teeth. The ease-off in the tooth height direction of meshing tooth surfaces is achieved by applying a head-cutter whose profile consists of two circular arcs, instead of a straight-line. The method of tooth contact analysis applied determines the path of contact, the potential contact lines, the separations along these lines, and the transmission errors. A computer program implements the method. By using this program the influence of the variation of machine tool settings and of head-cutter geometry on tooth contact is investigated and discussed.

  • Head-cutter for optimal tooth modifications in spiral Bevel Gears
    Mechanism and Machine Theory, 2009
    Co-Authors: Vilmos Simon
    Abstract:

    Abstract A method for the determination of optimal tooth modifications in spiral Bevel Gears based on improved load distribution and reduced maximum tooth contact pressure and transmission errors is presented. The modifications are introduced into the pinion tooth-surface by using a head-cutter with bicircular profile and with optimal diameter. In the optimization of tool parameters the influence of relative position errors of the mating Gears is included. By using the computer program developed for load distribution calculation, the influence of head-cutter parameters and relative position errors of the mating Gears on tooth contact and transmission errors is investigated. Based on the results obtained, the radii and the position of the circular tool profile arcs and the cutter diameter for pinion teeth finishing were optimized. By applying the optimal tool parameters, the maximum tooth contact pressure is reduced by 45% and the maximum angular position error of the driven gear by 60%, in regard to the spiral Bevel gear pair with a pinion manufactured by a cutter of straight-sided profile and of diameter determined by the commonly used methods.

Neelesh Kumar Jain - One of the best experts on this subject based on the ideXlab platform.

  • On simultaneous improvement of wear characteristics, surface finish and microgeometry of straight Bevel Gears by abrasive flow finishing process
    Wear, 2018
    Co-Authors: Anand C. Petare, Neelesh Kumar Jain
    Abstract:

    Abstract Improvement in operating performance, service life and transmission efficiency and reducing the noise of straight Bevel Gears (SBG) requires their better wear resistance, surface finish and microgeometry. Viscosity of the medium used in abrasive flow finishing (AFF) process and finishing time play very important role in achieving these objectives. This paper reports on simultaneous improvement of wear characteristics, surface finish and microgeometry of SBG by abrasive flow finishing (AFF) process by studying the effects of viscosity of AFF medium and finishing time so as to identify their optimum values through twenty experiments. Average and maximum surface roughness were used to study improvement in surface finish while, microgeometry was evaluated in parameters of pitch deviation and runout. Friction force, coefficient of friction, specific wear rate coefficient, wear volume, microhardness and microstructure of the worn surfaces were used to study the wear characteristics and wear mechanism of the best finished SBG. Use of AFF has significantly improved the wear characteristics, surface finish and microgeometry and quality of SBG. Reduced wear characteristics will reduce the frictional heating which will result in lower operating temperature of the Bevel Gears. Lower wear volume will improve their service life and mechanical efficiency. Microstructure study of the AFF best finished Bevel gear flank surfaces revealed that they are free from hobbing cutter marks, cracks, burrs, pits, surface roughness peaks, thermal distortion. The worn flank surface of the best finished Bevel gear have shown very less amounts of worn debris, pits and displacement of material and indicate scuffing mode of wear. This work helps in establishing AFF as an economical, sustainable and productive alternative process for finishing the Gears made of any material which can simultaneously improve surface finish, wear characteristics, microgeometry and quality of the Bevel Gears.

  • modeling and experimental validation of volumetric material removal rate and surface roughness depth of straight Bevel Gears in pulsed ech process
    International Journal of Mechanical Sciences, 2017
    Co-Authors: Sunil Pathak, Neelesh Kumar Jain
    Abstract:

    This paper describes development of theoretical models of volumetric material removal rate (MRR) and surface roughness depth (Rz) of straight Bevel Gears finished by pulse electrochemical honing (PECH) process in terms of the most influencing parameters namely applied voltage, pulse-on time, pulse-off time, finishing time, inter-electrode gap, electrolyte conductivity and workpiece gear rotary speed. Equations for computing flank surface area of gear tooth flank surfaces in terms geometric parameters of involute profile of straight Bevel Gears were also developed. The developed models were validated by conducting twelve experiments using one-factor-at-a-time approach and varying applied voltage, pulse-on time and pulse-off time each at four levels. Values and trends of variation of volumetric MRR and surface roughness depth predicted by the proposed models have shown very close agreement with corresponding experimental values and their trends. Minimum prediction errors for the proposed models were found to be −3.3% and 1% for volumetric MRR and surface roughness depth respectively. Models and validation results have also revealed the existence of optimum ranges of voltage, pulse-on time and pulse-off time to optimize volumetric MRR and depth of surface roughness. Analysis of different aspects of surface quality (i.e. surface finish, material ratio curve, micro-geometry, tooth flank topology) and surface integrity (i.e. microstructure and micro-hardness) of the best-finished gear have shown considerable improvements in them.

  • Effect of applied voltage and electrolyte parameters on pitch, runout, flank topology, and finishing productivity of the straight Bevel Gears in PECH process
    Materials and Manufacturing Processes, 2016
    Co-Authors: Sunil Pathak, Neelesh Kumar Jain, I. A. Palani
    Abstract:

    ABSTRACTThis paper describes improvements in the considered parameters of micro-geometry: flank surface topology and finishing productivity of 20MnCr5 alloy steel straight Bevel Gears through their finishing by pulsed electrochemical honing (PECH) process. Effects of three most important parameters of PECH process, namely applied voltage, electrolyte composition, and electrolyte concentration were investigated to identify their optimum values. Pre-identified values of other PECH parameters and an aqueous mixture of NaCl and NaNO3 as an electrolyte were used in the present work. Errors in pitch (i.e., single pitch error, adjacent pitch error, and cumulative pitch error) and runout were used to evaluate micro-geometry of the straight Bevel Gears while volumetric material removal rate was used to judge the finishing productivity of the PECH process. Topology of the gear tooth flank surface and microstructure of the best-finished Bevel Gears were also studied. The results revealed considerable improvements in...

  • Process Performance Comparison of ECH and PECH for Quality Enhancement of Bevel Gears
    Materials and Manufacturing Processes, 2014
    Co-Authors: Sunil Pathak, Neelesh Kumar Jain, I. A. Palani
    Abstract:

    This paper presents a comparative analysis of constant-current electrochemical honing (ECH) and pulsed electrochemical honing (PECH) for quality enhancement of straight Bevel Gears. The quality of straight Bevel Gears after finishing by ECH and PECH is compared focusing on tooth flank finish and microgeometry. Tooth flank finish was evaluated in terms of percentage enhancement in average roughness value, maximum roughness value, and 5-point roughness value. Percentage enhancements in pitch error, pitch variation error, accumulated pitch error, and total runout were used to evaluate the microgeometry of the Bevel Gears. It was found that the PECH process is capable of simultaneously enhancing the tooth flank finish and microgeometry of Bevel Gears by more than 50% as compared with ECH-finished Bevel Gears. The PECH-finished Gears also exhibited superior microstructure as compared with ECH-finished Gears. These improvements will enhance the service life and working performance of Gears.

  • on use of pulsed electrochemical honing to improve micro geometry of Bevel Gears
    Materials and Manufacturing Processes, 2014
    Co-Authors: Sunil Pathak, Neelesh Kumar Jain, I. A. Palani
    Abstract:

    Accuracy in micro-geometry is an important issue for Gears because it affects noise generation and transmission characteristics and consequently determines the operating performance and service life of the Gears. Various post-manufacturing processes are required to achieve the desired level of accuracy in micro-geometry of the Gears. This paper reports on use of pulsed-electrochemical honing (PECH) process to improve micro-geometry of the straight Bevel Gears and presents experimental optimization of three important parameters of PECH namely pulse-on time, pulse-off time, and finishing time. Seventeen experiments were conducted according to central composite rotatable approach of response surface methodology. The improvements in micro-geometry of Bevel Gears in terms of average percentage improvement in single pitch error, adjacent pitch error, cumulative pitch error, and in total runout were found as 34.22%, 39.58%, 13.34%, and 18.88%, respectively. These improvements are better than those achieved using...

Wei Cao - One of the best experts on this subject based on the ideXlab platform.

  • Microstress cycle and contact fatigue of spiral Bevel Gears by rolling-sliding of asperity contact
    Friction, 2020
    Co-Authors: Wei Cao, Si Ren, Ke Xiao
    Abstract:

    The rolling contact fatigue (RCF) model is commonly used to predict the contact fatigue life when the sliding is insignificant in contact surfaces. However, many studies reveal that the sliding, compared to the rolling state, can lead to a considerable reduction of the fatigue life and an excessive increase of the pitting area, which result from the microscopic stress cycle growth caused by the sliding of the asperity contact. This suggests that fatigue life in the rolling-sliding condition can be overestimated based only on the RCF model. The rubbing surfaces of spiral Bevel Gears are subject to typical rolling-sliding motion. This paper aims to study the mechanism of the micro stress cycle along the meshing path and provide a reasonable method for predicting the fatigue life in spiral Bevel Gears. The microscopic stress cycle equation is derived with the consideration of gear meshing parameters. The combination of the RCF model and asperity stress cycle is developed to calculate the fatigue life in spiral Bevel Gears. We find that the contact fatigue life decreases significantly compared with that obtained from the RCF model. There is strong evidence that the microscopic stress cycle is remarkably increased by the rolling-sliding motion of the asperity contact, which is consistent with the experimental data in previous literature. In addition, the fatigue life under different assembling misalignments are investigated and the results demonstrate the important role of misalignments on fatigue life.

  • transient behaviors of friction temperature and fatigue in different contact trajectories for spiral Bevel Gears
    Tribology International, 2020
    Co-Authors: Zongzheng Wang, Ying Zhang, Wei Cao
    Abstract:

    Abstract The dramatic changes in contact geometry, load, entraining and sliding velocity vectors along contact trajectories of spiral Bevel Gears may cause significant squeezing action. It suggests that the steady-state analysis at each discrete engaging point cannot effectively describe the tribological behavior in spiral Bevel Gears. The present study aims to systematically study the transient friction, temperature and contact fatigue behaviors in different contact trajectories for spiral Bevel Gears based on a newly developed transient mixed EHL model. It shows that the obtained transient friction coefficient is much higher than the steady-state when the Gears mesh in the first half of the engagement period. During the entire engagement period, the predicted transient fatigue life is significantly longer than the predicted steady-state fatigue life, which is of importance to the integrated and economical design of spiral Bevel Gears. The comparison with single half-sine waveform asperity demonstrated that the transient asperity contact pressure is much lower than that in quasi-steady state. The variation of flash temperature appears to be insignificant. Moreover, in different contact trajectories, the weakest point in one engagement period always occurs at a certain point when one teeth pair just finished the engaging-in and another pair of teeth completed engaging-out, and the toe contact exhibits the maximum frictional energy consumption and shortest fatigue life among them.

  • numerical simulation of transient mixed elastohydrodynamic lubrication for spiral Bevel Gears
    Tribology International, 2019
    Co-Authors: Zongzheng Wang, Jiaxu Wang, Wei Cao
    Abstract:

    Abstract In spiral Bevel Gears, the entraining velocity, contact load and radii of curvature along tooth surface are always changed dramatically, which results in remarkable transient squeezing effect on lubricating performance, especially it operates in high-speed and heavy-load conditions. Available elastohydrodynamic lubrication (EHL) and mixed EHL studies for spiral Bevel Gears are mainly performed under quasi-static (steady-state) assumptions which ignores these transient influences. Therefore, in this paper, a transient mixed EHL model for spiral Bevel Gears is presented, in which takes into account most variable parameters along meshing surface including contact load, contact radii of curvature, entraining and sliding velocity vectors. Note that all these transient parameters of spiral Bevel Gears are employed from the results of loaded tooth contact analysis (LTCA). In order to improve the computational efficiency and convergent accuracy with a relatively dense grids, the progressive mesh densification (PMD) method for this transient mixed EHL model is also introduced. A comparison between the present transient mixed EHL model and those data from literature is executed to verify the correctness of the newly developed model. After that, systematically investigations of transient squeezing impact are carried out for spiral Bevel Gears and compared with the corresponding steady-state EHL results with and without real machined surface roughness. The obtained results reveal that the transient squeezing action can significantly affect the film thickness distribution in each contact zone and along the meshing track line in spiral Bevel Gears, and lead to dramatic growth in asperity contact area as well. Besides, the steady-state EHL appears to be greatly overestimated the lubricating characteristics for spiral Bevel Gears.

  • A numerical method to investigate the temperature behavior of spiral Bevel Gears under mixed lubrication condition
    Applied Thermal Engineering, 2019
    Co-Authors: Lai Gan, Jiaxu Wang, Ke Xiao, Wei Cao
    Abstract:

    Abstract Thermal behaviors under mixed lubrication regime are closely to the load-carrying capacity of spiral Bevel Gears, especially, in heavy load and high speed. In order to analyze the bulk and flash temperature behaviors, this paper proposes a numerical method which integrates the mixed elastohydrodynamic lubrication model with a finite element method based on thermal analysis. Heat generation in mixed lubrication regime is determined as functions of the applied load, sliding velocityand friction coefficient. The friction is solved by recently developed mixed elastohydrodynamic lubrication model with the consideration of surface roughness and arbitrary entrainment angle. Heat transfer analysis is conducted by application of the time- and position-varying heat flux and convection coefficient boundary condition on single tooth finite element model. The results clearly show that the major high temperature zone for bulk temperature is located nearby tooth root and the temperature in boundary lubrication is more serious compared with mixed lubrication. The edge contact at the tooth top leads to severe high temperature. The flash temperature behavior in entire rotation period indicates the influence of thermal characteristics on risk of scuffing.

  • effect of contact path on the mixed lubrication performance friction and contact fatigue in spiral Bevel Gears
    Tribology International, 2018
    Co-Authors: Wei Cao, Jiaxu Wang, Ke Xiao
    Abstract:

    Abstract The contact path in spiral Bevel Gears may have significant effect on the lubrication breakdown and surface failure. However, available study mainly focus on the influence of contact path on the contact stress distribution with the assumptions of dry contact and smooth surface. In reality, these Gears are lubricated and the surfaces are quite rough with three-dimensional (3D) topography. The present study aims to systematically investigate the effect of contact path on the mixed lubrication characteristics, friction and contact fatigue in spiral Bevel Gears with the consideration of surface roughness. A comprehensive analysis for gearing geometry, kinematics, and contact load with different contact path affected by assembling parameters is executed based on the loaded tooth contact analysis (LTCA). The corresponding lubrication characteristics, friction coefficient and flash temperature, as well as the fatigue life are conducted in a wide range of operating condition based on a recently developed mixed EHL model for spiral Bevel Gears. Obtained results reveal that the contact path is vital to lubrication performance, efficiency improvements and fatigue prevention. In particular, the contact path nearby toe of gear flank appears to be a weak path due to the smaller film thickness, larger friction coefficient, higher flash temperature and lower relative fatigue life.

Alain Bernard - One of the best experts on this subject based on the ideXlab platform.

  • New methodology to reduce the transmission error of the spiral Bevel Gears
    CIRP Annals - Manufacturing Technology, 2014
    Co-Authors: Julien Astoul, J. M. Linares, Emmanuel Mermoz, M. Sartor, Alain Bernard
    Abstract:

    New methods and tools have been developed the last years to improve the understanding of gear meshing. Mechanical industries attach growing attention to the dynamic behavior of mechanical transmissions, including vibration and noise that result. The transmission error of the gear, which measures the intensity of one of the main causes of dynamic phenomena, can be considered as a relevant indicator of gear performance. This paper presents a new design method of spiral Bevel Gears, the objective of this method being to reduce their quasi-static transmission error. The proposed approach is based on an optimization process including loaded meshing simulations. The simulation model has been evaluated using a helicopter tail gearbox as bench test. Measurement results are given, showing a good correlation with predictions. © 2014 CIRP.

Te Fang - One of the best experts on this subject based on the ideXlab platform.

  • on the prediction of friction coefficient and wear in spiral Bevel Gears with mixed tehl
    Tribology International, 2017
    Co-Authors: Jiange Zhang, Shaojun Liu, Te Fang
    Abstract:

    Abstract A prediction model of the friction coefficient and wear of the spiral Bevel Gears in the mixed lubrication condition is proposed. Effect of a coupling thermo-elasto-hydrodynamic phenomenon on tooth surface should be considered comprehensively prior to the execution of tooth wear analysis. An effort is devoted to application of TEHL with rough surface contact to analyze the performance of spiral Bevel Gears in terms of the pressure, flash temperature, friction coefficient, and particularly wear rate. Wear mechanism and rules under a condition of the mixed lubrication are revealed to provide evidence for gear design and engineering application. And comparison of the prediction wear depth with the experimental measurements shows good agreement.

  • Determination of surface temperature rise with the coupled thermo-elasto-hydrodynamic analysis of spiral Bevel Gears
    Applied Thermal Engineering, 2017
    Co-Authors: Jiange Zhang, Te Fang
    Abstract:

    Abstract In order to determine the temperature rise of the tooth surface as a result of the friction heat in mixed EHL, a coupled thermo-elasto-hydrodynamic analysis is carried out in consideration of the load shearing, mixed lubrication characteristics, heat generation in the contact region. The procedure necessary to establish the model of a coupled thermo-elasto-hydrodynamic analysis is also described. Considering the lubrication condition of tooth surface, a great challenge of moving heat source applied on complex curved surface is solved to improve the present thermal analysis method of spiral Bevel gear. Based on loaded tooth contact analysis of spiral Bevel Gears and EHL analysis of point contact, steady-state and transient thermal analyses are conducted. And the comparison of the analytical results with the experimental measurements shows good agreement. Effects of asperity contact on temperature rise in spiral Bevel gear teeth surfaces were also discussed.