Rolling bearings are a common component in many fields of technology. A rolling bearing comprises an outer bearing ring, an inner bearing ring, and a number of rolling elements positioned in between the outer and the inner bearing rings. The inner and the outer bearing rings have a raceway for the rolling elements.
In some fields of technology, such as, for example, wind powered turbines, it is desired to equip at least one of the bearing rings of a rolling bearing with a gear structure. Examples of known methods of accomplishing this, i.e. to equip a bearing ring of a rolling bearing with a gear structure, comprise the following: attaching a gear structure to the outer or inner periphery of the bearing ring, or forming the gear structure on the periphery, outer or inner, of the bearing ring, by means of machining.
A drawback of the first method i.e. attaching a gear structure to a bearing ring is that the joint between the gear structure and the bearing ring to which it is attached will be weakened over time by such factors as stress, creeping, fretting corrosion and wear, which may eventually cause the joint to come apart. This drawback is particularly bothersome in applications in which large forces are present, such as, for example, the wind powered turbines mentioned before.
A drawback of the second method, i.e. machining a gear structure in the periphery, inner or outer, of a bearing ring, is that machining a gear structure inherently causes weaknesses in the structure.
A bearing ring, at least in the case of an outer ring, will inherently need to be a hollow ring, and a drawback of all of the methods mentioned above is that it is difficult to manufacture a hollow ring with a gear structure on its periphery with sufficient preciseness and quality both with regards to the gear structure and the bearing ring in its entirety.