Análise macroscópica e microscópica de tensões de contato em engrenagens

Abstract

FZG tests have a lot of purposes, among them is the characterization of the mechanisms of wear that a gear can suffer. This thesis aims to look for correlations between the types of wear mechanisms at gear teeth that were tested and the roughness profile presented before and after the tests by means of comparation between macroscopic and microscopic stresses on the contact. The gears used are made with AISI 4320 steel, quenched and tempered. The characterization was done by means of the study of the Hertz’ stress that consider the macroscopic geometry and so that the geometry ware considered, the superficial roughness was measured at characteristic zones. That study presents for the macroscopic contact, maximum stress about 1,5MPa or more. In the case of the microscopic consideration, that consider Ra roughness, were considered the manufacturing state and after test. Were found stress peaks about 19x109MPa at the pinion addendum when it was evaluated the gear with a manufacturing state and when was considered the after test state, the maximum stress change the location to primitive diameter, reaching in order of 21x109MPa while the addendum showed a drop in stress values to about 50% of the initial value.