Session: PTG-02-02: Gear Analysis, Materials, and Fatigue 2

Paper Number: 111881

111881 - The Effect of Geometrical Quality on the Stress-State in the Plastic Gear 

Gear manufacturing errors affect the load sharing between the meshing gears as also the load distribution along the individual tooth’s width. High quality grades are especially hard to achieve for injection molded plastic gears. On the other hand, plastic materials are much more flexible than metals and the teeth deflect and comply under load, leading to an improved load distribution. Larger deviations lead however to a localized contact area resulting in stress concentration and early failure. This study aims to investigate the effect of gear manufacturing quality on the mechanical state of the plastic gear, and consequently also on the gear-life. An original systematic combination of numerical and experimental methods was employed to study these effects. The deviation of geometrical quality parameters, i.e. lead profile and pitch were found to have a substantial effect on the stress (root and flank) state of the gear. The effect of lead deviation was found to be most pronounced for the quality grades Q10 to Q12, while improving the lead quality from Q10 to Q8 did not exhibit a substantial improvement in the load distribution and the corresponding stress. Same was observed for pitch deviation, where again the most pronounced effect was found when improving the quality grade from Q12 to Q10. Quality factors are proposed which can be considered when conducting the root stress and flank pressure calculations in order to include the effect of uneven load distribution in case of larger geometric deviations.

Presenting Author: Damijan Zorko University of Ljubljana, Faculty of Mechanical Engineering

Presenting Author Biography: Education/ Academic studies:

2019 - PhD in Mechanical Engineering (topic: Design and calculation methods for plastic gears with a non-involute gear profile)

2013 - Master’s degree in Mechanical engineering

2011 - Bachelor’s degree in Mechanical engineering


Professional career:

2022 - now Assistant Professor, University of Ljubljana, Faculty of Mechanical Engineering, Laboratory for engineering Design

2019 – 2022 Postdoctoral Researcher, University of Ljubljana, Faculty of Mechanical Engineering, Laboratory for engineering Design

2016 – 2019 Senior Researcher & Teaching Assistant, University of Ljubljana, Faculty of Mechanical Engineering, Laboratory for engineering Design

2013 – 2016 Researcher & Teaching Assistant, University of Ljubljana, Faculty of Mechanical Engineering, Laboratory for engineering Design

Authors:

Damijan Zorko University of Ljubljana, Faculty of Mechanical Engineering
Nikola Vukašinović University of Ljubljana, Faculty of Mechanical Engineering
Borut čErne University of Ljubljana, Faculty of Mechanical Engineering