Heidenhain Absolute Rotary Encoder

Rotary encoders with integral bearing that are conceived for separate shaft coupling are designed with a solid shaft. The recommended coupling to the measured shaft compensates radial and axial tolerances. Angle encoders for separate shaft couplings permit higher shaft speeds.

Rotary encoders without integral bearing operate without friction. The two components - the scanning head and the scale disk, drum, or tape - are adjusted to each other during assembly. The benefits are:
Large diameter of hollow shaft
For high shaft speeds
No additional starting torque