IJERT-Design of Involute Spur Gears with Asymmetric teeth & Direct gear Design (original) (raw)
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Design of Involute Spur Gears with Asymmetric teeth & Direct gear Design
2012
Design of gears with asymmetric teeth that enables to increase load capacity, reduce weight, size and vibration level.. standard tool parameters and uses nonstandard tooth shapes to provide required performance for a particular custom application. This makes finite element analysis (FEA) more preferable than the Lewis equation for bending stress definition. This paper does not describe the FEA application for comprehensive stress analysis of the gear teeth. It sents the engineering method for bending stress balance and minimization.
Parametric analysis of asymmetric involute spur gear tooth
International Journal of Powertrains, 2019
The focus of this work is a geometric parameter of an asymmetric involute spur gear tooth. Gear strength is influenced by tooth geometry. So, knowledge of tooth geometric is required which will help to improve the strength of a gear tooth. In this article, a data generated from an equations and presented in form of graph for better interpretation of the effect of drive side pressure angle on various parameters like contact ratio, HPSTC radius, load angle, tip thickness, thickness of tooth at pitch circle radius, critical section thickness, bending moment arm height, etc. Parametric analysis of gear tooth gives an idea about how different parameters affect tooth geometry of an asymmetric involute spur gear tooth which is essential for modelling and manufacturing. Parametric analysis helps to calculate optimise drive side pressure angle. It is also predicted or calculates % reduction in bending stress at the root of the tooth without using FEA. It is explained with illustration and results are compared to justify it.
Analysis of Stress and Bending Strength of Involutes Spur Gears with Fillet Asymmetric Profile
Analysis estimating the variation of maximum bending stress and contact ratio depending on tooth number and pressure angle of the drive side has been developed for asymmetric drives. The bending stress analyses have been performed with the aid of FEM for asymmetric and symmetric tooth. The stress results obtained by FEM analyses and estimated by the developed program have been compared. It has been proved that asymmetric teeth have better performance than both symmetric teeth it has been confirmed that, as the pressure angle on the drive side increases, the bending stress decreases and the bending load capacity increases. It has been seen that, while the value of maximum bending stress is changing, the location of maximum bending stress remains the same in finite element analysis.
Analysis of Symmetric and Asymmetric Spur Gear to Improve Bending Load Carrying Capacity
Gear is a machine element used to transmit motion and power between rotating shafts by means of progressive engagement of projections called teeth, a pair of spur gear teeth in action is generally subjected to two types of cyclic stresses as bending stresses and contact stress. These stresses cause the bending and pitting failure respectively. These types of failures can be minimized by proper analysis of the problem during the design stage and creating proper tooth profile. Normally, gear analysis is combination of various analysis method, including calculations related to the tooth stresses, wear or scoring. In this paper, bending stress analysis of the symmetric and asymmetric spur gear will be performed, while trying to design spur gears to improve the bending load of the teeth; tooth profile modification is done by modifying the pressure angle. Then bending stresses calculated using ANSYS, from that results comparison between symmetric and asymmetric spur gear is done.
Reduction of gear fillet stresses by using one-sided involute asymmetric teeth
Mechanism and Machine Theory, 2009
For increasing the load carrying capacity of geared power transmissions several tooth designs alternative to the standard involute have been proposed. The use of non-involute teeth has a number of disadvantages and for this reason asymmetric involute-type teeth have been studied as a promising alternative. In this paper the idea of one-sided involute asymmetric spur gear teeth is introduced to increase load carrying capacity and combine the good meshing properties of the driving involute and the increased strength of noninvolute curves. These novel teeth are intended for constant direction of rotation although they can be used in a limited way for reverse rotation. Both flanks are fully generated by a hob, the design of which is also investigated. The increase in load carrying capacity can reach up to 28% compared to the standard 20°involute teeth.
In this paper a new generation of asymmetric tooth profile gear is considered to enhance the dynamic behavior and vibroacoustic properties of toothed gear system. This paper presents a non linear dynamic model as a single degree of freedom equation for teeth meshing gear system which includes static and dynamic transmission error in order to investigate the influence of time varying mesh stiffness and periodic tooth errors on dynamic load factor for symmetric and asymmetric spur teeth profile. A new model of nonlinear time varying mesh stiffness is based on four types of deflections with consideration a small pressure angle for loaded tooth profile side and high pressure angle for another side. The complicated variation of meshing stiffness as a function of contact point along the mesh cycle is studied. Typical dynamic load factor equations are developed for symmetric and asymmetric tooth gear in single and double tooth contact by studied symmetrictooth with pressure angle (20 0 /20 0) and two pairs of asymmetric teeth (14.5 0 /25 0 & 20 0 /25 0). The effect of pressure of asymmetry and static transmitted load on transmission error and dynamic load factorare studied. The results indicate enhancement percentage in transmission error and dynamic load factor for asymmetric teeth profile compare with that symmetric tooth profile. 1. Introduction For the combination of high speeds and heavy loads encountered in modern engineering applications of the toothed gear, a precise analysis of the gear dynamic behavior is imperative. A New generation of asymmetric teeth gear play important role to increase load capacity, endurance ,long life and reduction vibration and noise. Transmission error (Tm) which is mean the difference between theoretical and actual angular position of driven gear when driver gear operating at constant speed ,therefore transmission error represent major excitation source for vibration and noise in geared system ,and reduction in transmission error represent major aim for researchers many decades ago, moreover gear vibration and noise level arise due to other several reasons [1] such as the error in the gear teeth profile at the contact point , misalignment between shaft axes , impact between mating teeth ,backlash, sliding and rolling friction between mating surface of gears ,bearing and housing ….etc. Most efforts to reduce the vibration and noise generation at the mesh have been directed towards improving the accuracy of manufacture. But, experience proves that the improving of manufacturing accuracy does not reduce the vibration and noise level considerably [2]. Several studies in literature have been conducted on the design and stress analysis of asymmetric tooth gear, little of them transact this approach dynamically, kaplelevich[3] present analytical method to design a gear with asymmetric tooth side surface, he consider a high pressure angle for the drive side and low pressure angle for the coast side teeth , Yang [4] provide geometrical modeling to design the asymmetric helical gear meshing when assembly errors are present, he constructed Stress analysis for the helical and the cylindrical form ,Mallesh et al. [5,6] generate asymmetric spur gear tooth geometry for different pressure angles on drive and coast side using computer programme to create a finite element model of gear tooth and investigate the effect of bending stress at the critical section for different pressure angles, different number of teeth and module , Ekwaro-Osire et al. [7] employ the inverse problem technique for asymmetric gear teeth which include photo elastic experimental work , Wang et al.[8] extend the edge – based smoothed point interpolation method (ES-IPM) in the bending strength analysis of asymmetric gear with various drive pressure angles side which generated by a special rack cutter , Agrawal et al. [9] Had been tested an asymmetric gear virtually with ANSYS code under a predefined loading and it has been investigated how bending stress changes at the fillet region of the asymmetric gear .Karpat et al. [10] present dynamic analysis of spur gear with symmetric and asymmetric teeth gear ,they consider high pressure angle for the drive side and low pressure angle profile for the coast side teeth ,they develop a MATLAB-based virtual tool to analyze dynamic behavior of spur gears with asymmetric teeth. In This work a new mathematical model for nonlinear mesh stiffness and dynamic load factor formula are developed for symmetric & asymmetric teeth meshing gear system then investigate the influence of asymmetry on dynamic load factor and transmission error .
Design and Efficiency of an Asymmetric Gear
International Journal of Mechanical and Production Engineering Research and Development, 2019
Presently, Gears suffer backlash as well as interference and undercutting. These defects can be eliminated by increasing the pressure angle or by increasing the addendum of the matting gear design for many years. In additional alteration, which is very rarely used is to make the gears Asymmetric mesh gear drive, means that larger and smaller pressure angles are applied for the driving side and coast side, respectively. To obtain the effect of the above spur gear, tooth parameters are to be designed and modelled. Later, the pinion and gear in mesh is fabricated.
Comparison of Bending Stresses in Involute and Cycloidal Profile Spur Gear Tooth
In this paper, the analysis of involute and cycloidal tooth spur gear design has been done to investigate the bending stresses induced in the gear tooth for different modules by finite element analysis. The mathematical models have been generated based on the theory of gearing. Models are made in Creo Parametric software tool. The bending stresses induced in the gear tooth obtained from FEA corresponding to different modules for both involute and cycloidal profile spur gear are compared with the values obtained by Lewis equation. It is observed that the FEA results are having a slight variation with Lewis equation. It is found that the bending stress reduces with the increase in module and the bending stress values for involute profile spur gear is less than the cycloidal profile for the same module and involute spur gear teeth is stronger than cycloidal spur gear teeth.