AGMA 05FTM08

Tooth Contact Analysis (TCA) and Loaded Tooth Contact Analysis(LTCA) are two powerful tools for the design and analysis of spiralbevel and hypoid gear drives. Typical outputs of TCAand LTCAare thegraphs of contact patterns and transmission errors. TCA and LTCArespectively simulate gear meshing contact characteristics underlight load and under significant load. TCA and LTCA programs havebeen widely employed by gear engineers and researchers in theirdesign of high strength and low noise spiral bevel and hypoid geardrives.

Application of modern CNC hypoid gear generators has brought newconcepts in design and generation of spiral bevel and hypoid gearswith sophisticated modifications. This paper presents newdevelopments in TCA and LTCA of spiral bevel and hypoid gears. Thefirst part of the paper describes a new universal tooth surfacegeneration model which is developed with consideration of theuniversal motion capabilities of CNC bevel gear generators. The newuniversal model is based on the kinematical modeling of the basicmachine settings and motions of a virtual bevel gear generatorwhich simulates the cradle-style mechanical hypoid gear generatorsand integrates both facemilling and face hobbing processes. Thetool geometry is generally represented by four sections, blade tip,Toprem, profile, and Flankrem. Mathematical descriptions of geartooth surfaces are represented by a series of coordinatetransformations in terms of surface point position vector, unitnormal, and unit tangent. Accordingly, a new generalized TCAalgorithm and program are developed.

In the second part of this paper the development of a finiteelement analysis (FEA) based LTCA is presented. The LTCA contactmodel is formulated using TCA generated tooth surface and filletgeometries. The FEA models accommodate multiple pairs of meshingteeth to consider a realistic load distribution among the adjacentteeth. An improved flexibility matrix algorithm is formulated, inwhich the nonlinear formation of the area of contact commonto thegear and pinion teeth is predicted by introducing specialized gapelementswith considerations of deflection and deformation due totooth bending, shearing, local Hertzian contact, and axlestiffness.

The advanced TCAand LTC Aprograms are integrated intoGleasonCAGEt for Windows software package. Two numerical examples,a face-hobbing design and a face milling design, are illustrated toverify the developed mathematical models and programs.

Edition:

05

Published:

10/01/2005

Number of Pages:

14

File Size:

1 file , 1.3 MB