Rotor module
Bearings and Shaft
Driveshaft
From full shaft to hollow shaft
At first we used a full shaft, but after the calculation we decided on a hollow shaft. The shaft is still massive – and it has to be, because of the high torque.
An adaptor is the connection between shaft and generator.
The driveshaft turns between the upper flanged pendulum bearing and the lower self-made plain bearing. This is an improvement over regular bearings and cylindrical plain bearings, because it is flexible and simple to mount.
Upper bearing
Stainless steel pendulum bearings aren’t standard because they are too expensive. Normally you would use waterproof bearing modules, but that is too complicated for the Rotor – so we ended up in China. There was the idea to fix an axial bearing with span sets, but you need a conical bearing seat for that. We couldn’t find that kind of bearing made of stainless steel. A Chinese producer offered it for 100 pieces or more. That was not worth it for the prototype, so we used a flanged bearing that is axially fixed by two screws.
Lower bearing
We talked to many bearing manufacturers, such as boat and underwater builders. Pendulum functions on sliding bearings are used in joint bearings on hydraulic cylinders, but only translationally, without rotation between driveshaft and bearing. That’s the reason for our own construction.
Outlook
What could be improved?
The bearing system performs well with very low friction. Costs and complexity could still be optimized.