Session: PTG-06-01: Lubrication and Efficiency

Paper Number: 141667

141667 - Local Calculation of Load-Dependent Gear Power Losses of Cylindrical Gears 

The primary design criteria for gearboxes are (i) power density and load capacity, (ii) noise, vibration, and harshness, and (iii) efficiency and heat balance. To meet these design criteria, it is essential to employ accurate calculation models throughout the design process. ISO/TR 14179-2:2001 divides the total power loss into portions of gears, bearings, sealings, and other machine elements, of which the load-dependent gear power loss often makes up the most significant portion. Literature offers many calculation methods of varying levels of detail for those, with mesh-local models promising higher accuracy, but nevertheless, they are rarely employed, i.a., due to lack of validation. This study systematically compares mesh-averaged with mesh-local models, employing a twin-disk tribometer and various gear geometries. The study includes a wide range of operating conditions and different gear oils. Three calculation levels (I, II, and III) are defined, focusing on tooth contact analysis and friction coefficients.

The results indicate high agreement between the calculated and measured power losses, with the mesh-local models demonstrating a high accuracy. When comparing the calculated load-dependent gear power losses for an internal gear geometry, the mesh-local calculation model (level III) calculates 29% lower load-dependent gear power losses than the mesh-average calculation model (level II). This finding aligns with initial experimental results on the FZG internal gear test rig.

In conclusion, the mesh-local models demonstrate high accuracy across different gear geometries and operating conditions. These findings suggest that these models are viable for broader applications. The agreement with measurements facilitates accurate calculations in the design phase, ensuring compliance with design criteria and optimal gearbox performance.

 

Presenting Author: Constantin Paschold Technical University of Munich, School of Engineering and Design, Department of Mechanical Engineering, Gear Research Center (FZG)

Presenting Author Biography: Name:
Constantin Paschold

Professional Background:
B. Sc. Automotive and Combustion Engine Technology, Technical University of Munich, 2010-2014
M. Sc. Automotive and Combustion Engine Technology, Technical University of Munich, 2014-2017
Research Associate at Gear Research Center (FZG), 2017-2020
Team Leader Efficiency and Heat Balance at Gear Research Center (FZG), since 2020

Specialist Fields:
Gearbox Design, Efficiency, Heat Balance, Software Development, Numerical Calculation, Experimental Validation

Authors:

Constantin Paschold Technical University of Munich, School of Engineering and Design, Department of Mechanical Engineering, Gear Research Center (FZG)
Thomas Lohner Technical University of Munich, School of Engineering and Design, Department of Mechanical Engineering, Gear Research Center (FZG)
Karsten Stahl Technical University of Munich, School of Engineering and Design, Department of Mechanical Engineering, Gear Research Center (FZG)