Utvärdering av en ny typ av lagerinbyggnad för traktionsmotorer
The thesis evaluates a new kind of bearing arrangement in a traction motor that ABB hasdeveloped. Since the arrangement is designed in a new and innovative way it needs to beevaluated to see if it is safe to use. In today?s traction motors, bearings with a big internalclearance (C4-clearance) are used. The basic idea of the new arrangement is to reduce the fitsbetween the bearing and shaft/house. By doing so, it will be possible to use bearings with lessinternal clearance (C3-clearance). The new arrangement makes the assembling in productiona lot easier.When reducing the fits it is important to assure that the bearing still not moves around theshaft during operation. To do that, axial force will be used to press the bearing against a highfriction shim fitted between the bearing and the shaft. The friction shim is made of a thin steelfoil with diamond particles fixed in a nickel matrix on both sides.The thesis evaluates several questions concerning the new arrangement. Some of thequestions concerns different bearing selections, internal radial clearance calculations, forcedistribution caused by the friction shim, bearing lubrication and bearing currents. To answerthis questions theoretical models, FEM-analysis?s and practical investigations are used. Thepractical investigation mainly involves an investigation of the surface quality of the coatingon the friction shim.The calculations of the bearings internal radial clearance show that this area will not be aproblem in the new arrangement. One important problem that might result in damage bearingrings is fretting between the bearing and the shaft. This problem can be solved by using gluein the contact area between the bearing and the shaft. The investigation of the friction shimshowed some surface defects with chipped off coating as the most crucial. This issue is ofgreat importance because it might result in coating particles inside the bearing with a potentialbearing failure as a result.