The society of today puts increasing demands on energy efficiency in most businesses to reduce resource depletion, energy consumption and emissions. One way to increase the efficiency of many of the mechanical systems we use daily is to improve the machine components that are used to construct these machines and products. These machine components could be for instance gears, rolling element bearings and cam followers. All of these machine components are a part of machines and products we use daily such as cars, boats, trucks and industrial transmissions. Gears, rolling element bearings and cam followers works in a lubrication regime called elastohydrodynamic lubrication. By reducing the friction generated in these kinds of machine components it is possible to reduce the power losses, thereby leading to more fuel efficient vehicles, or industrial transmissions with lower energy consumption.
There are several ways to increase the efficiency of machine components. One possibility is to develop improved lubricants with properties that reduce the friction generation in the machine component. Here it is also possible to work with environmentally friendly lubricants such as glycerol or vegetable oils to reduce or eliminate the lubricants negative impact on the environment.
Elastohydrodynamic lubrication is often characterized in three different lubrication regimes. In full film lubrication a sufficiently thick lubricant film is generated between the contacting surfaces so that the total load is carried by the lubricant film and no contact occurs between the surfaces. This lubrication regime is in most cases most advantageous since both friction and wear is as low as possible. In mixed lubrication is part of the load carried by the lubricant film while the rest is carried by contact between the surfaces. In general, the larger amount of the load that is carried by the surface contacts, the higher is the friction and wear. Finally, in boundary lubrication, the entire load is carried by surface contacts and both friction and wear are at its highest level.
The importance of surface engineering has increased in recent years for friction reduction in elastohydrodynamically lubricated contacts. By using smoother surfaces it is possible for machine components to work in full film lubrication at a larger extend, thus reducing friction and wear. The use of surface coatings has also increased tremendously during the last decade to improve functionality and for instance reduced wear and friction.
The aim of my research is to give greater understanding of the process of friction generation in elastohydrodynamically lubricated contacts and to develop new lubricants with less environmental impact and increased efficiency of machine components. My research also includes the development of surface coatings for improved efficiency of machine components.