Tooth Contact Analysis and Manufacture on Multitasking Machine of Large Sized Straight Bevel Gears With Equi Depth Teeth

Abstract

Straight bevel gears are widely used in the plant of largesized power generation when the gears have large size. The purpose of this study is to manufacture the largesized straight bevel gears with equidepth teeth on a multitasking machine. The manufacturing method has the advantages of arbitrary modification of the tooth surface and machining of the part without the tooth surface. For this study, first, the mathematical model of straight bevel gears by complementary crown gears considering manufacture on multitasking machine is proposed, and the tooth contact pattern and transmission errors of these straight bevel gears with modified tooth surfaces are analyzed in order to clarify the meshing and contact of these gears. Next, the numerical coordinates on the tooth surfaces of the bevel gears are calculated and the tooth profiles are modeled using a 3DComputerAided Design (CAD) system. Fiveaxis control machines were utilized. The gearwork was machined by a swarf cutting using a coated carbide end mill. After rough cutting, the gearwork was heattreated, and it was finished based on a ComputerAided Manufacturing (CAM) process through the calculated numerical coordinates. The pinion was also machined similarly. The real tooth surfaces were measured using a coordinate measuring machine and the tooth flank form errors were detected using the measured coordinates. As a result, the obtained tooth flank form errors were small. In addition, the tooth contact pattern of the manufactured largesized straight bevel gears was compared with those of tooth contact analysis. The data showed good agreement.