Research on Gear Cutter Tooth Profile for Semi-Topping: A Case of a Helical Gear

Author(s):  
Y. Ariga ◽  
Shiyeyoshi Nagata

Abstract Gear tooth tips are frequently chamfered to prevent nicks or scuffing on the tooth surface. Some of the hob cutters and pinion cutters can be chamfered but many types of cutters should be used for a particular range of tooth numbers since the amount chamfering largely varies depending on the tooth number. However, intensive efforts in the design have made it possible to produce cutters with little variation of chamfering amount for a wide range of tooth numbers. The error in the amount of chamfering by a single cutter designed by the above method can be maintained within ±10 % for gears with tooth numbers ranging from 16 to 94. It was found that three cutters of the conventional design are required for keeping the error within the same range for cutting gears within a given range of tooth numbers. The paper describes the tooth design method of the hob cutter with little variation of chamfering amount along changes in number of teeth to be machined and demonstrates that chamfering errors are maintained within practically allowable ranges for profile shift cutting or helical gear cutting with the use of this cutter.

2013 ◽  
Vol 823 ◽  
pp. 257-260
Author(s):  
Jie Wu ◽  
Jia Quan Wang

This article find that one of the effecting the double circular arc gear s running performance is the double circular arc gear tooth profile precision, through analysis to the running-in properties of double arc gear. The problems about tooth profile precision of gear hobs caused by the current profiling theory and approximate design method of gear hobs are analyzed. In the design of circular arc gear hob, use the space engagement theory, can eliminating the tooth error. Acquiring the equation of hobs basic of worm tooth surface by analytical and calculation that the establishment of basic gear rack and worm of hob meshing. The hob not only eliminate the tooth profile error in manufacturing, but also improve the running performance of double circular arc gear, and provides the theory evidence for engineering practice.


2004 ◽  
Vol 127 (4) ◽  
pp. 656-663 ◽  
Author(s):  
A. Kahraman ◽  
P. Bajpai ◽  
N. E. Anderson

In this study, a surface wear prediction model for helical gears pairs is employed to investigate the influence of tooth profile deviations in the form of intentional tooth profile modifications or manufacturing errors on gear tooth surface wear. The wear model combines a finite-element-based gear contact mechanics model that predicts contact pressures, a sliding distance computation algorithm, and Archard’s wear formulation to predict wear of the contacting tooth surfaces. Typical helical gear tooth modifications are parameterized by an involute crown, a lead crown, and an involute slope. The influence of these parameters on surface wear are studied within typical tolerance ranges achievable using hob/shave process. The results indicate that wear is related to the combined modification parameters of a gear pair rather than individual gear parameters. At the end, a design formula is proposed that relates the mismatch of contacting surface slopes to the maximum initial wear rate.


Author(s):  
Mattias Svahn

The fillet of the gear tooth is highly stressed in operation; so for heavily loaded gears, the fillet geometry must be controlled. The manufacturer's task is to, within acceptable tolerances, produce the gear to the designer's specifications regardless of the manufacturing method. Most often gear cutting tools are used that work under generating conditions. The tool will form the gear tooth; so to produce the specified gear geometry and, especially, the fillet geometry, this tool must be conjugated to the same basic rack as the gear to cut. However, this gives a risk that the tooth tip of the tool will be undercut, and if this occurs the tool will not cut the intended gear fillet. In this report, novel analytical equations are derived, which predict the limit when the tool tip will be undercut. It is shown that if the gear tooth should be conjugated to the standard basic rack with a circular fillet, which is the normal case, very large tool-tooth numbers are needed for pinion shaper cutters and gear skiving cutters to avoid this type of undercut. However, the minimum tooth number to achieve a smooth continuous tool-tooth profile is reduced by modifications to the fillet of the basic rack profile.


Author(s):  
Ravi Datt Yadav ◽  
Anant Kumar Singh ◽  
Kunal Arora

Fine finishing of spur gears reduces the vibrations and noise and upsurges the service life of two mating gears. A new magnetorheological gear profile finishing (MRGPF) process is utilized for the fine finishing of spur gear teeth profile surfaces. In the present study, the development of a theoretical mathematical model for the prediction of change in surface roughness during the MRGPF process is done. The present MRGPF is a controllable process with the magnitude of the magnetic field, therefore, the effect of magnetic flux density (MFD) on the gear tooth profile has been analyzed using an analytical approach. Theoretically calculated MFD is validated experimentally and with the finite element analysis. To understand the finishing process mechanism, the different forces acting on the gear surface has been investigated. For the validation of the present roughness model, three sets of finishing cycle experimentations have been performed on the spur gear profile by the MRGPF process. The surface roughness of the spur gear tooth surface after experimentation was measured using Mitutoyo SJ-400 surftest and is equated with the values of theoretically calculated surface roughness. The results show the close agreement which ranges from −7.69% to 2.85% for the same number of finishing cycles. To study the surface characteristics of the finished spur gear tooth profile surface, scanning electron microscopy is used. The present developed theoretical model for surface roughness during the MRGPF process predicts the finishing performance with cycle time, improvement in the surface quality, and functional application of the gears.


Author(s):  
J Hedlund ◽  
A Lehtovaara

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.


2013 ◽  
Vol 535-536 ◽  
pp. 271-274
Author(s):  
Jeongsuk Lim ◽  
Sunghoon Kang ◽  
Young Seon Lee

The dimensional change of tooth profile by heat treatment of helical gear was investigated by experimental and numerical approaches. Especially, the three-dimensional elasto-plastic finite element (FE) simulation was adopted to analyze the elastic deformation during load, unloading, ejecting of workpiece. Quenching simulation was also carried out to investigate the change of tooth profile on the forged gear. In experiments, the amount of elastic deformation of the forged gear was quantitatively determined by comparing the tooth profiles on the forged gear and die. The dimensional change of the forged gear tooth after quenching was also evaluated from the comparision of the cold forged and quenched gear teeth. From experimental works, it was found that the amounts of dimensional changes after forging and quenching of helical gear are 10 and 10 μm, respectively.


2013 ◽  
Vol 753-755 ◽  
pp. 1258-1261
Author(s):  
Zhong Yi Ren ◽  
Bi Qiong Jiang

Arc-gear tooth profile is complex, especially quadruple-arc gear, it cant be grinding by generating method, form grinding method is still has some difficult in wheel dressing. In this article, the author use software VC++6.0 and OpenGL developed a new and special gear software, when the tooth number and modulus of arc-gear to be machined and grinding wheel diameter is given, this software can generate disk form grinding wheel 3D model,this software is useful to arc-gear form grinding wheel dressing.


2012 ◽  
Vol 426 ◽  
pp. 159-162 ◽  
Author(s):  
Man Dong Zhang ◽  
H.H. Zhao ◽  
Ming Lv

Using electroplating CBN hard gear-honing-tools with standard involute, the vicinity of the workpiece tooth pitch circle will be a “mid concave” error, the root of the tooth will be a “dig root” error generally. For the formation factors of the error are more complex, it is difficult to calculate errors with an exact analytical method. To this end, by using Pro/E and ANSYS software, the contact analysis of electroplating CBN hard honing process was simulated. The honed tooth surface normal deformation analysis was the important means to determine extent of tooth profile error, through the normal deformation analysis based on simulation results, the location and extent of normal deformation was determined. Practice shows that the location and extent of the normal deformation has been a certain relationship with processing gear tooth profile errors. It is provided a theoretical basis to make the gear-honing tooth surface modification as possible.


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