Rotation device, and drive shaft for rotation device

A drive shaft for use with a rotation device, the drive shaft comprising an outer layer and an inner layer, the outer layer being a tubular structure defining an accommodating space, the inner layer arranged in the accommodating space and defining a central lumen for receiving therein an external mechanism, wherein the outer layer is rotatable about the central lumen, and the inner layer is rollable relative to both the outer layer and the external mechanism and thus rolling friction is created between the inner layer and the external mechanism through the inner layer,

• wherein the outer layer is a spring coil formed of one or more wires, slits are provided between at least two turns of the spring coil to allow a fluid to flow therethrough to an inner surface and/or an outer surface of the outer layer,
• wherein the inner layer includes a plurality of rollers disposed on the inner surface of the outer layer,
• wherein the outer layer is connected to the inner layer magnetically, the plurality of rollers have magnetic properties and are attracted to the outer layer, or wherein the outer layer has magnetic properties, and
• wherein a plurality of rollways are arranged on an internal side of the outer layer, and the plurality of rollways are axially spaced apart from one another, and the plurality of rollers are evenly arranged in each of the rollways around the central lumen.