scholarly journals Effect of Tooth Surface Modification on Dynamic Transmission Efficiency of Double Helical Gear Trains

2021 ◽  
Vol 26 (4) ◽  
pp. 274-286
Author(s):  
Feng Wang ◽  
Xing Xu ◽  
Jiaqi Xia ◽  
Hongbo Que
Keyword(s):  
Three Dimensional ◽  
Transmission Efficiency ◽  
Helical Gear ◽  
Dynamic Loads ◽  
Tooth Surface ◽  
Time Dynamic ◽  
Theoretical Perspectives ◽  
Simulation And Experiment ◽  
Gear Trains ◽  
Transmission Quality

To analyse the influence mechanism of vibration loads on dynamic transmission efficiency (DTEF) of double helical gear trains (DHGT), a calculation method of DTEF which takes into consideration the real-time dynamic loads is proposed from the perspective of improving both efficiency and precision. The average DTEF is taken as the dynamic objective function of optimization for three-dimensional modification technology of tooth surface. An engineering example is given in form of numerical simulation, which proves that the average DTEF with the consideration of dynamic loads is obviously lower than the static transmission efficiency (STEF), especially for the resonance speed region. The results also show that the DTEF after 3-D modification is significantly improved, owing to the improvement of meshing state of tooth surface. The comparison of DTEF with different loads and speeds via simulation and experiment furtherly demonstrates the credibility of this theoretical perspectives. This study gives the explanation on the importance of DTEF in determination of driveline parameters and estimation of transmission quality of DHGT. The developed method for DTEF analysis is practical in engineering, and establishes a reliable foundation for further research on design of high-quality double helical gear trains.

scholarly journals Tooth surface modification of double-helical gears for compensation of shaft deflections

2021 ◽  
Vol 12 (2) ◽  
pp. 819-835
Author(s):  
Lan Liu ◽  
Qiangyi Ma ◽  
Jingyi Gong ◽  
Geng Liu ◽  
Xiaomei Cao
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Helical Gear ◽  
Tooth Surface ◽  
Helical Gears ◽  
Partial Load ◽  
Tooth Surfaces ◽  
Tooth Modification ◽  
Herringbone Gear ◽  
Bearing System

Abstract. Based on gear meshing theory, the tooth surface equation with tooth profile modification parameters is deduced, the tooth surfaces of unmodified and modified gears are constructed, the three-dimensional model of unmodified and modified double helical gear-shaft-bearing system is established and then the three-dimensional contact finite element model of double helical gear-shaft-bearing system is established and the load-bearing contact analysis of the tooth surface is carried out. The actual contact state of the tooth surfaces of double helical gears under different shaft stiffness and power transmission paths is investigated, and the influence of tooth modification parameters on the load distribution of the tooth surfaces of double helical gear pairs is studied. The results show that the tooth surface bearing the contact of the herringbone gear system has the phenomenon of partial load due to the supporting deformation, and the unmodified herringbone gear has obvious contact stress concentration. However, the phenomenon of partial load and stress concentration can be effectively improved by gear tooth modification.

A novel tooth surface modification methodology for wide-faced double-helical gear pairs

2021 ◽  
Vol 160 ◽  
pp. 104299
Author(s):  
Bing Yuan ◽  
Geng Liu ◽  
Yanjiong Yue ◽  
Lan Liu ◽  
Yunbo Shen
Keyword(s):  
Surface Modification ◽  
Helical Gear ◽  
Tooth Surface ◽  
Tooth Surface Modification

scholarly journals Application of the erosion algorithm in modeling of structures behavior under impulse loads

2019 ◽  
Vol 221 ◽  
pp. 01003
Author(s):  
Pavel Radchenko ◽  
Stanislav Batuev ◽  
Andrey Radchenko
Keyword(s):  
Finite Element ◽  
High Velocity ◽  
Three Dimensional ◽  
Computer Software ◽  
Dynamic Loads ◽  
Complex Structures ◽  
Numerical Studies ◽  
Contact Surfaces ◽  
Fracture Of Materials ◽  
Solid Bodies

The paper presents results of applying approach to simulation of contact surfaces fracture under high velocity interaction of solid bodies. The algorithm of erosion -the algorithm of elements removing, of new surface building and of mass distribution after elements fracture at contact boundaries is consider. The results of coordinated experimental and numerical studies of fracture of materials under impact are given. Authors own finite element computer software program EFES, allowing to simulate a three-dimensional setting behavior of complex structures under dynamic loads, has been used for the calculations.

scholarly journals Optimal design of high efficiency double helical gear based on dynamics model

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Fengxia Lu ◽  
Xuechen Cao ◽  
Weiping Liu
Keyword(s):  
Dynamic Model ◽  
High Efficiency ◽  
Bending Strength ◽  
Sliding Friction ◽  
Elastohydrodynamic Lubrication ◽  
Optimization Method ◽  
Transmission Efficiency ◽  
Helical Gear ◽  
Transmission System ◽  
Vibration Displacement

AbstractA 16-degree-of-freedom dynamic model for the load contact analysis of a double helical gear considering sliding friction is established. The dynamic equation is solved by the Runge–Kutta method to obtain the vibration displacement. The method combines the friction coefficient model based on the elastohydrodynamic lubrication theory with the dynamic model, which provides a theoretical basis for the calculation of the power loss of the transmission system. Moreover, the sensitivity analysis of the parameters that affect the transmission efficiency is carried out, and an optimization method of meshing efficiency is proposed without reducing the bending strength of the gears. This method can directly guide the design of the double helical gear transmission system.

Investigation of Noise Features of Planetary Gear Trains Based on Human Aural Characteristic

2017 ◽  
Author(s):  
Masao Nakagawa ◽  
Dai Nishida ◽  
Deepak Sah ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama
Keyword(s):  
Gear Tooth ◽  
Structural Complexity ◽  
Planetary Gear ◽  
Transmission Error ◽  
Sound Level ◽  
Tooth Surface ◽  
Surface Error ◽  
Planetary Gear Trains ◽  
Tooth Stiffness ◽  
Gear Trains

Planetary gear trains (PGTs) are widely used in various machines owing to their many advantages. However, they suffer from problems of noise and vibration due to the structural complexity and giving rise to substantial noise, vibration, and harshness with respect to both structures and human users. In this report, the sound level from PGTs is measured in an anechoic chamber based on human aural characteristic, and basic features of sound are investigated. Gear noise is generated by the vibration force due to varying gear tooth stiffness and the vibration force due to tooth surface error, or transmission error (TE). Dynamic TE is considered to be increased because of internal and external meshing. The vibration force due to tooth surface error can be ignored owing to almost perfect tooth surface. A vibration force due to varying tooth stiffness could be a major factor.

Vibration-based fault diagnosis of helical gear pair with tooth surface wear considering time-varying friction coefficient under mixed EHL condition

2021 ◽  
pp. 1-16
Author(s):  
Siyu Wang ◽  
Rupeng Zhu
Keyword(s):  
Dynamic Response ◽  
Hydrodynamic Lubrication ◽  
Helical Gear ◽  
Calculation Model ◽  
Tooth Surface ◽  
Time Varying ◽  
Gear Pair ◽  
Surface Wear ◽  
Mesh Stiffness ◽  
Helical Gear Pair

Abstract Based on “slice method”, the improved time-varying mesh stiffness (TVMS) calculation model of helical gear pair with tooth surface wear is proposed, in which the effect of friction force that obtained under mixed elasto-hydrodynamic lubrication (EHL) is considered in the model. Based on the improved TVMS calculation model, the dynamic model of helical gear system is established, then the influence of tooth wear parameters on the dynamic response is studied. The results illustrate that the varying reduction extents of mesh stiffness along tooth profile under tooth surface wear, in addition, the dynamic response in time-domain and frequency-domain present significant decline in amplitude under deteriorating wear condition.

A parameterized numerical method for generating discrete helical gear tooth surface allowing non-standard geometry

2008 ◽  
Vol 222 (6) ◽  
pp. 1033-1038 ◽  
Author(s):  
J Hedlund ◽  
A Lehtovaara
Keyword(s):  
Gear Tooth ◽  
Numerical Approach ◽  
Helical Gear ◽  
Tooth Surface ◽  
Tool Profile ◽  
Standard Geometry ◽  
Gear Manufacturing ◽  
Involute Gears ◽  
Gear Geometry ◽  
Tooth Flank

Gear analysis is typically performed using calculation based on gear standards. Standards provide a good basis in gear geometry calculation for involute gears, but these are unsatisfactory for handling geometry deviations such as tooth flank modifications. The efficient utilization of finite-element calculation also requires the geometry generation to be parameterized. A parameterized numerical approach was developed to create discrete helical gear geometry and contact line by simulating the gear manufacturing, i.e. the hobbing process. This method is based on coordinate transformations and a wide set of numerical calculation points and their synchronization, which permits deviations from common involute geometry. As an example, the model is applied to protuberance tool profile and grinding with tip relief. A fairly low number of calculation points are needed to create tooth flank profiles where error is <1 μm.

scholarly journals Evaluation of Induced Settlements of Piled Rafts in the Coupled Static-Dynamic Loads Using Neural Networks and Evolutionary Polynomial Regression

2017 ◽  
Vol 2017 ◽  
pp. 1-23 ◽  
Author(s):  
Ali Ghorbani ◽  
Mostafa Firouzi Niavol
Keyword(s):  
Neural Networks ◽  
Finite Difference ◽  
Polynomial Regression ◽  
Three Dimensional ◽  
Dynamic Loads ◽  
Prototype Model ◽  
Evolutionary Polynomial Regression ◽  
Dimensional Finite Element ◽  
Heavy Loads ◽  
Three Dimensional Finite Element

Coupled Piled Raft Foundations (CPRFs) are broadly applied to share heavy loads of superstructures between piles and rafts and reduce total and differential settlements. Settlements induced by static/coupled static-dynamic loads are one of the main concerns of engineers in designing CPRFs. Evaluation of induced settlements of CPRFs has been commonly carried out using three-dimensional finite element/finite difference modeling or through expensive real-scale/prototype model tests. Since the analyses, especially in the case of coupled static-dynamic loads, are not simply conducted, this paper presents two practical methods to gain the values of settlement. First, different nonlinear finite difference models under different static and coupled static-dynamic loads are developed to calculate exerted settlements. Analyses are performed with respect to different axial loads and pile’s configurations, numbers, lengths, diameters, and spacing for both loading cases. Based on the results of well-validated three-dimensional finite difference modeling, artificial neural networks and evolutionary polynomial regressions are then applied and introduced as capable methods to accurately present both static and coupled static-dynamic settlements. Also, using a sensitivity analysis based on Cosine Amplitude Method, axial load is introduced as the most influential parameter, while the ratio l/d is reported as the least effective parameter on the settlements of CPRFs.

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