Aprimoramento do projeto de uma máquina de torque e tensão para avaliar coeficientes de atrito de fixadores

Abstract

This work presents an improvement of the conceptual design of a torque tension machine developed by Alves (2018). The purpose of the machine is to perform tests according to the ISO 16047:2005 which is an update of the DIN 946. The parameters to be determined with the equipment are: total torque applied (T), thread torque (Tth), angle of turn of the fastener and compression force of the bolted joint (F). These allow the calculation of important parameters to study clamping elements, such as torque coefficient (K), coefficient of total friction (μ𝑡𝑜𝑡), coefficient of friction between threads (μ𝑡ℎ) and coefficient of friction between bearing surfaces (μb). In addition, the equipment will be able to plot graphs of clamp force versus angle of turn, torque applied versus angle of turn and torque applied versus clamp force. The requirements for equipment design are: fasteners with diameters of ½” to 1. ½”, the materials are ASTM A320 and Inconel 718 with yield strength of 1034 MPa and the length of 200 to 450 mm. The main improvements are related to the power system, machine structure, angle measurement, linear guide design and ball bearing.