Frictional power losses on spur gears with tip reliefs. The friction coefficient role. (March 2018)

• Record Type: Journal Article
• Authors: Diez-Ibarbia, A.; Fernandez-del-Rincon, A.; de-Juan, A.; Iglesias, M.; Garcia, P.; Viadero, F.
• Is Part Of: Mechanism and machine theory. Volume 121(2018)
• Page Start: 15
• Page End: 27
• Publication Date: 2018-03
• Subjects: Efficiency -- Friction coefficient -- Power losses -- Load sharing -- Tip relief; Machine theory -- Periodicals; Machinery -- Periodicals; Machines -- Périodiques; Génie mécanique -- Périodiques; Machine theory; Machinery; Periodicals; 621.81
• DOI: 10.1016/j.mechmachtheory.2017.10.003
• Languages: English
• ISSNs: 0094-114X

Abstract

Highlights: The efficiency calculation uses an enhanced Load Contact Model, which allows for obtaining the Load sharing and the Friction coefficient with a high level of accuracy. The use of an advanced friction coefficient formulation, which can reproduce the friction behaviour in dry contact conditions, boundary, mixed and fluid film lubrication and is dependent of the contact force. The level of torque and the profile modification effects are taken into account in the Load sharing and Friction coefficient calculation. Abstract: In this proposal, the effect of the friction coefficient on the efficiency of spur gears with tip reliefs was analysed. For this purpose, the efficiency values using an average friction coefficient along the mesh cycle were compared with those obtained implementing an enhanced friction coefficient formulation, which is based on elastohydrodynamic lubrication fundamentals. In this manner, it can be established the differences between both formulations in the efficiency and friction coefficient values, as well as the advantages of using this enhanced friction coefficient with respect to formulations implemented in traditional approaches of efficiency calculation. In addition to studying the impact of the friction coefficient choice on efficiency, the profile modifications influence on the friction coefficient and efficiency was also assessed. In this regard, three tip relief case studies were set out; pinion tip reliefs, driven wheel tip reliefs and profile modifications in both gears. From the results, it was inferred that the choice of friction coefficient formulation clearly influences the efficiency in gear transmissions with tip reliefs, obtaining discrepancies between both formulations with regard to which tip relief case study provides the lowest efficiency values.