TRANSMISSION FOR A WIND TURBINE

A transmission which may find particular utility in wind turbine application, but may also be used in other applications. The transmission comprises a fixed gear ring, a first drive member rotationally supported within the fixed gear ring, the first drive member defining a plurality of radially arranged apertures each of which accommodates a tooth element. Each tooth element has a tooth tip region and a tooth base that are opposed along a tooth axis. The first drive member further comprises a radially outer face and a radially inner face, wherein the tooth tip regions of the tooth elements engage a corresponding gear profile defined by the fixed gear ring. The transmission further comprises a second drive member which is rotationally supported such that it extends within the first drive member. The second drive member defines an cam profile which slidably engages the tooth base of each of the plurality of tooth elements. At least one of the tooth elements comprise: a first lubrication port at a first axial position on the tooth element, a second lubrication port at a second axial position on the tooth element, and an internal lubrication passage connecting between the first lubrication port and the second lubrication port. Beneficially, the tooth elements of the invention are provided with internal flow passages to distribute lubrication fluid to different parts of the tooth element. This means that fewer passages and drillings are required in the input member within the tooth element slides. Moreover, the configuration of the tooth element means that the tooth element is lubricated more effectively.