Absolute rotary encoders • Stator coupling for plane surface • Hollow through shaft

Mounting variants

In rotary encoders with integral bearing and stator coupling, the graduated disk of the encoder is connected directly to the shaft to be measured. The scanning unit is guided on the shaft via ball bearings, supported by the stator coupling. During angular acceleration of the shaft, the stator coupling must absorb only that torque resulting from friction in the bearing, thereby minimizing both static and dynamic measuring error. Moreover, the coupling mounted on the stator compensates axial motion of the measured shaft. Other benefits of the stator coupling are:

• Simple mounting
• Short overall length
• High natural frequency of coupling
• Hollow-through shaft possible

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

Rotary encoders with integral bearing

HEIDENHAIN ERN, ECN and EQN rotary encoders with integral bearing and mounted stator coupling are characterized by simple mounting and short overall length. Possible applications range from simple measuring tasks to position and speed control on servo drives. The hollow shaft of these encoders is slid directly onto and fastened to the shaft to be measured.

ROD, ROC and ROQ rotary encoders from HEIDENHAIN have their own bearings and are sealed. They are robust and compact. These encoders are coupled by the rotor to the measured shaft through a separate coupling that compensates axial motion and misalignment between the encoder shaft and measured shaft.

ExN 100 Features:

• For large shaft diameters
• Hollow-through shaft, available inside ø: 20 mm, 25 mm, 38 mm, 50 mm
• Housing outside diameter: 87 mm