Effect of tribological properties on tooth root fatigue failure of polymer gears

Matkovič, Sebastjan (author), Kalin, Mitjan (mentor)

The use of polymer gears in various applications has increased significantly in recent years, from the automotive industry to household appliances and industrial machinery. This is due to the favourable properties of polymer materials, including low weight, cost efficiency, low noise emissions and the ability to operate without the presence of external lubrication. However, the mechanical performance of polymer gears is lower compared to conventional metal gears, which leads to problems such as shorter service life and susceptibility to various types of failure. Due to thermal stability and elasticity differences, existing gear design standards tailored for metal gears are inadequate for polymer gear design. Although efforts have been made to develop guidelines specifically for polymer gears, challenges remain, particularly in accurately predicting fatigue life due to limited data and uncertainties in material behaviour. This thesis addresses key areas critical to understanding and improving the tooth root performance of polymer gears, focusing on tribological properties, geometry changes during operation, and operation in different environmental conditions. Through a comprehensive investigation of these factors, this thesis aims to improve the reliability and longevity of polymer gears by investigating the effect of tribological properties on tooth root fatigue failure and the possibilities for its prediction.

• Language: English
• Keywords: polymer, tribology, friction, gear, tooth root, fatigue
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [S. Matkovič]
• Year: 2024
• Number of pages: XX, 1318 str.
• PID: 20.500.12556/RUL-159540
• UDC: 539.3:539.92:620.178.4:621.83.052(043.3)
• COBISS.SI-ID: 203138307
• Publication date in RUL: 12.07.2024

MATKOVIČ, Sebastjan, 2024, Effect of tribological properties on tooth root fatigue failure of polymer gears [online]. Doctoral dissertation. Ljubljana : S. Matkovič. [Accessed 25 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=159540

Secondary language

• Language: Slovenian
• Title: Vpliv triboloških značilnosti na utrujanje korena zoba polimernega zobnika

Abstract

V zadnjih letih se je uporaba polimernih zobnikov v različnih aplikacijah, od avtomobilske industrije do gospodinjskih aparatov in industrijskih strojev, močno povečala. Povečanje uporabe polimernih zobnikov na vse več področjih je posledica materialnih lastnosti, kot so majhna masa, enostavna izdelava, nizki stroški, nizka raven hrupa in vibracij ter možnost obratovanja brez dodatnega mazanja. Vendar je mehanska zmogljivost polimernih zobnikov v primerjavi z običajnimi kovinskimi zobniki slabša, kar povzroča težave, kot sta krajša življenjska doba in dovzetnost za različne vrste odpovedi. Zaradi razlik v termični stabilnosti in elastičnosti so obstoječi standardi za oblikovanje zobnikov, prilagojeni za kovinske zobnike, neustrezni za konstruiranje polimernih zobnikov. Čeprav so bila vložena prizadevanja za razvoj smernic posebej za polimerne zobnike, ostajajo izzivi, zlasti pri točnem napovedovanju življenjske dobe polimernega zobnika zaradi omejenih podatkov in negotovosti pri obnašanju polimernega materiala. Ta doktorska disertacija obravnava področja, ki so ključna za razumevanje in izboljšanje življenjske dobe korena zoba polimernega zobnika, s poudarkom na triboloških lastnostih, spremembah geometrije med delovanjem in delovanju v različnih okolijskih pogojih. S celovito raziskavo teh dejavnikov je cilj tega dela izboljšati življenjsko dobo polimernih zobnikov z raziskovanjem vpliva triboloških lastnosti na utrujanje zoba polimernega zobnika in možnosti za napovedovanje dobe trajanja.

• Keywords: polimeri, tribologija, trenje, zobnik, koren zoba, utrujanje