Gears are an important part of many machines. This thesis is a study in how new mechano-chemical surface treatments can be used to improve the efficiency in gear transmissions, specifically those relating to electric vehicles. The primary equipment used for this research is the FZG-test rig, a rig dedicated for the evaluation of lubricant and gear behaviour. To achieve an understanding of the effects of surface treatment, how gear contacts interact, and how geometry affects the efficiency, a substantial background study was performed, mixing various fields of knowledge and incorporating results from previous projects utilizing the FZG-test rig. Throughout the experimental phase of the project many goals had to be adjusted based on various problems encountered. Notable gear wear was observed in addition to the fact that many of the examined gears fell outside some of the specified manufacturing tolerance requirement. As a result, the data acquired from the testing is inconclusive. It is not possible to clearly establish the correlation between the effects of the new surface treatments method and efficiency due to the uncertainty in the interaction between lack of quality and a previously untested lubricant. These results are however still of benefit as to establish future test conditions and to identify the potential problems with FZG-testing. / Kugghjul är en viktig del i många maskiner. Denna rapport är en studie i hur nya mekaniska-kemiska ytbehandlingar kan tillämpas för att förbättra effektiviteten i kugghjulstransmissioners, specifikt för tillämpning i elektriska fordon. Den centrala utrustningen som använts i denna undersökning är en FZG-testrigg, en testrigg vars huvudsakliga uppgift är utvärdering av smörjmedel och kugghjulsbeteende. För att uppnå en förståelse av effekterna av ytbehandlingar, hur kugghjulskontakter interagerar, och hur kugghjulsgeometri påverkar effektiviteten, har en betydlig bakgrundstudie genomförts. Denna studie blandade flera olika kunskapsområden, samt resultat från tidigare projekt som även tillämpande FZG-testriggen. I projektets experimentella fas krävdes justeringar i flera av projektets mål på grund av problem som uppstod. Betydlig nötning kunde identifieras i samband med att flera av kugghjulen var utanför de nödvändiga tillverknings toleranskraven. I följd av detta är data från experimenten som utfördes icke-slutgiltiga. Det är inte möjligt att med säkerhet etablera ett samband mellan effekterna av den nya metoden av ytbehandling och effektivitet på grund av den osäkerhet som uppstår via kvalitetsbrister och ett smörjmedel som tidigare ej testats på KTH. Detta är fortfarande viktiga positiva resultat för att kunna etablera framtida test förhållanden och identifiera möjliga problem i experiment med FZG-testriggen.

The automotive industry is constantly being challenged by customers and authorities to enhance the efficiency of the internal combustion engine (ICE) in order to achieve improved fuel consumption and reduced emissions. There are several interfaces within the design of an ICE that causes frictional losses, one of them is the valvetrain. An approach to reducing the friction in the valvetrain of modern engines is to implement cam-follower rollers, resulting in a rolling rather than sliding contact when interacting with the camshaft. The prominent type of wear in rolling contacts is surface fatigue, and specifically a phenomenon called micropitting. The company in collaboration with this project is Applied Nano Surfaces Sweden AB (ANS), located in Uppsala, Sweden. The company have specialized in surface treatment methods of mechanical components. ANS has developed a mechano-chemical treatment method called ANS Triboconditioning, which have shown beneficial friction and wear reducing properties when applied to metal surfaces. This thesis was conducted to investigate how the ANS Triboconditioning would affect the frictional behaviour compared to established surface treatment methods and the occurrence of micropitting in rolling contact configurations. Two types of test programs was implemented into a Wazau UTM 2000 Twin-Disc Tribometer. No clear trend could be established from the micropitting tests and therefore no conclusion regarding if ANS Triboconditioning affects the occurrence of micropitting damage in a positive or negative manner could be stated. The results from the friction test indicated an overall reduction in friction for the test specimens that had been treated with ANS Triboconditioning when compared to specimens that only had been treated with already established surface treatment methods. Summarized, additional tests and analyses are necessary in order to statistically confirm the observed results and determine their respective trends.

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