The processing accuracy of the gear

Sergiu Mazuru,Maxim Casian,Serghei Scaticailov,L Slătineanu,M Boca,G Oancea,C.E Panait,R Ibanescu,M Coteata,G Nagit,A.M Mihalache,O Dodun,V Merticaru,M.I Ripanu,P Kyratsis

doi:10.1051/matecconf/201711201026

Abstract

The paper presents analysis of processing quality of gears. A special attention was drawn to detecting and removing burns, the existence of which greatly reduced operating properties of gears. The study emphases the influence of schemes, processing modes and abrasive tools features on the physico-mechanical layer of teeth processed and phase changes, micro-cracks appearances, depth and degree of hardening, meaning and character of residual stresses distribution.

Highlights

The formation of the surface layer during deep grinding of gears from alloyed steels occur under the influence of an uneven thermodynamic influence on the work-piece and, as a consequence, the appearance of inhomogeneous elasto-plastic deformations along the section of cavity profile between the adjacent teeth and the structure-phase transformations from heating and cooling of metal
This leads to distortion of the teeth profile, to the appearance of a step error and a decrease in the kinematic accuracy of the gear and to the appearance of grinding defects on the treated surfaces
The quality of the surface layer by the change in microstructure and micro-hardness was estimated after the final passage

Summary

Introduction

The formation of the surface layer during deep grinding of gears from alloyed steels occur under the influence of an uneven thermodynamic influence on the work-piece and, as a consequence, the appearance of inhomogeneous elasto-plastic deformations along the section of cavity profile between the adjacent teeth and the structure-phase transformations from heating and cooling of metal. The appearance and development of grinding nature defects, before all, of burns and micro-cracks, caused by structural-phase changes in the surface layer, depends on the temperature and the time of its action. Under optimal conditions of gear grinding by various rolling patterns or profile processing by highly porous abrasive wheels, as experimental studies have shown, production tests and experience of industrial application, burns and micro-cracks on the machined surfaces of the teeth are not observed. Taking into account a significant reduction in the operational properties of gears by the formation of defective layers with burns, the introduction of new technologies of non-burn gear grinding is an important condition for ensuring high reliability and durability of tooth wheels in exploitation

Results of metallographic analysis

Elimination of burns

Conclusions