Glidytor och ytjämnhet med avseende på friktion och tätning
Gliding and sealing functions in Öhlins shock absorbing systems sets great demands onthe contacting surfaces. In this particular case, the bushings and the sealings on acylinder piston. The surface wanted is a surface with both low frictional forces and smallleakage. This study was done with the goals of investigating and determining existingsurfaces due to the frictional force and leakage. How can we in an easy mannerdescribe these?A number of ten front forks were part of a main study. These were all measured withrespect to frictional force, leakage and surface roughness and then polished in foursteps with a micro finishing method. Following every step, the measurements wererepeated in goal of seeing what actually happens during the polishing.The results follow a pattern where a better surface generates less frictional forces and asmaller leakage, which also makes good sense. Since all front forks goes through thesame polishing method and thereby obtains a similar pattern of polishing stripes, theRa-value is enough to describe these surfaces with. Surfaces with the same Ra-valuecan, from a generally point of view, vary for example in friction. Therefore you shouldname the method the material has been worked upon, together with the Ra-value, in theengineering drawing.As an alternative method, a number of front forks where trumbled. This resulted in lowerfrictional forces, but the surface roughness became more complicated and higher topscould 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 indescribing these surfaces. This must be the natural step to move on further with. Itwould give a more consistent method to describe surfaces with different kind of workingup methods. But still, in cases where the surface is equally worked up upon this studyshows that the Ra-value is enough.