In the rotary encoders /trasducers with its own bearing and stator coupling the graduated disc is directly connected to the shaft to be measured. The scanning head is mounted on a support connected with a stator joint and with ball bearings to the graduated disk holder. With this configuration, at shaft angular accelerations, the joint on the stator must withstand only the torque resulting from the friction of the bearings, thus minimizing static and dynamic measurement errors. The stator mounted joint also compensates for axial displacements of the crankshaft.
- for axial displacements of the drive shaft
- possibility of passing through the hollow shaft
- simplicity of assembly
- reduced axial dimensions
- high intrinsic frequency coupling
The rotary encoders /trasducers with their own bearing and designed for use with a separate joint have a solid shaft. The joint recommended for coupling to the measured shaft compensates for centering errors and misalignments. For rotary encoders with separate shaft coupling they are allowed greater number of revolutions. The rotary encoders /trasducers without bearing operate in the absence of contact.
The two components (the scanning head and the scale disk, drum, or tape) are calibrated to each other during assembly.
The advantages are:
- Large hollow shaft diameter
- High speed
- absence of additional starting torque