Projeto, fabricação, construção e testes de um tribômetro FZG reduzido com carregamento variável

Abstract

The widespread use of gears in the industrial productive sector provides engineering solutions for power transmission problems and leads to scientific researches in mechanical engineering to improve the efficiency of gearboxes by reducing the wear and the friction. The improvement of the lubrication is a way to reduce friction and wear on the engaged gear pair. Thus, this work aims to build and test a tribometer capable of reproducing the contact between cylindrical spur gears in order to promote wear on their previously selected teeth. The conceptual design was based on the tribometer developed in the FZG Institute from the Technical University of Munich which is standardized by DIN ISO 14635-1: 2000, ASTM D 5182-97 and DIN 51354-1. The tribometer consists of a power transmission between two gearboxes interconnected by two parallel axes in a back-to-back power recirculation format. The project has: (a) a loading system with standard weights that aims to accelerate the wear on the gear teeth by applying torque to the system by means of a caliper-disk brake system; (b) a rigid base of structural aluminum profiles that has rigidity and flexibility for expanding the tribometer in the future; (c) a mechanical torque limiter with torque preload in order to ensure gear engagement; and (d) an electrical system controlled by a programmable frequency inverter. The projected components were manufactured at UFRN or purchased on the market and, subsequently, were assembled at UFRN. After assembly, the tribometer underwent a initial test which aimed to: (i) verify the induction to wear on the teeth of the gears with the aid of enlarged images; and (ii) map the machine's working conditions and variables. The rotation and loading parameters were varied following a factorial planning 3². The response variable “electric current” was analysed with the aid of the response surface method.