Glidytor och ytjämnhet med avseende på friktion och tätning

Sammanfattning: Gliding and sealing functions in Öhlins shock absorbing systems sets great demands on the contacting surfaces. In this particular case, the bushings and the sealings on a cylinder piston. The surface wanted is a surface with both low frictional forces and small leakage. This study was done with the goals of investigating and determining existing surfaces due to the frictional force and leakage. How can we in an easy manner describe these? A number of ten front forks were part of a main study. These were all measured with respect to frictional force, leakage and surface roughness and then polished in four steps with a micro finishing method. Following every step, the measurements were repeated in goal of seeing what actually happens during the polishing. The results follow a pattern where a better surface generates less frictional forces and a smaller leakage, which also makes good sense. Since all front forks goes through the same polishing method and thereby obtains a similar pattern of polishing stripes, the Ra-value is enough to describe these surfaces with. Surfaces with the same Ra-value can, from a generally point of view, vary for example in friction. Therefore you should name the method the material has been worked upon, together with the Ra-value, in the engineering drawing. As an alternative method, a number of front forks where trumbled. This resulted in lower frictional forces, but the surface roughness became more complicated and higher tops could be seen. This gave a bigger leakage and therefore was not studied any further. The bearing capacity was studied in this study and showed to be a reliable parameter in describing these surfaces. This must be the natural step to move on further with. It would give a more consistent method to describe surfaces with different kind of working up methods. But still, in cases where the surface is equally worked up upon this study shows that the Ra-value is enough.