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In oil-lubricated worm gears, all moving components cause power losses during operation. These losses depend, among other things, on the viscosity of the lubricant used, which in turn is determined by the temperature present in the gearbox. The dependency between the temperature and the power dissipation is mutual, and they influence each other. For the analysis of gearboxes under transient conditions, the relationship among operating conditions, power dissipation, and temperature must be considered. In this paper, a method for the analysis of these interrelationships is presented, which is based on the combination of tribological simulation and thermal networks. With the developed calculation model, the gearbox efficiency and the temperature over time can be estimated for arbitrary load cases. The calculation results are compared with measurements on a real gearbox.

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In this work, the dependence of the friction and wear behaviour in dry-lubricated steel-bronze contact on the dry lubricant used and on the substrate material (steel or bronze) under constant load was investigated. For this purpose, a block two-disc test rig was used, with the dry lubricants PA66-PTFE-cb as blocks, which were produced via chemical bonding (cb) of polyamide 66 (PA 66) and radiation-modified polytetrafluoroethylene (PTFE). The results provide a good basis for the selection of a suitable dry lubricant and the counter body for the transfer of the dry lubricant in dry lubricated worm gears consisting of a steel worm and a bronze wheel.

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For high performance racing applications as well as to achieve global emission goals, the efficiency of chain drives in vehicles is of great importance. In previous studies research on drive chains for motorcycle transmissions and timing drives of combustion engines is done with regard to efficiency and wear of the entire drive trains. Hence a test rig, the chain joint tribometer, was built. That enables to do wear and friction research on all parts inside of a chain joint like pin and bush. In conventional test rigs for efficiency investigation in circulation mode, the effects of different friction contact points overlap. So, research on the tribological system "chain joint contact" is in the focus. This rig can represent arbitrary load curves, in particular the contact force and the relative motion of a real chain drive. The chain joint tribometer closes the gap between investigations on whole chain drives standard tribometer tests. In this paper, results of friction analysis using drive chain segments in the arrangement of serial production are presented. Differences are distinguished between different chains having deviating surface roughnesses, which proves that the used tribometer is an adequate setup to analyze drive chains with regard to friction.