Operating instructions

Principles of Rotary Encoders
11
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Encoder Design
Solid Shaft Encoders
Solid shaft encoders feature a solid drive
shaft that must use an additional
coupling to link the encoder shaft
to the application’s drive shaft. The
spring-based coupling compensates
for misalignment. Belts, pinions,
measuring wheels and cable pulls
can also be mounted to the solid
drive shaft. Depending on the type of
coupling used, it is important to observe the maximum shaft
load, since excessively high radial or axial forces can damage
the encoder.
Advantages of solid shaft encoders:
• Simple construction
• Higher environmental protection rating
• Can be mechanically and electronically disengaged from
the application, depending on coupling
Clamping Flange
The encoder can be mounted using the clamping flange,
which ensures that the rotational axis is centered. The
threaded holes on the encoder face can also be used.
Servo Flange (synchro flange)
The encoder can be mounted using the synchro groove with
mounting components, by using the threaded holes on the
encoder face, or by using a mounting bracket.
Hollow Shaft Encoders
Hollow shaft encoders use a continuous
borehole or a blind hole (recessed hollow
shaft encoder) which houses the
drive shaft. Integrated hub and
shaft connections make linking
the encoder and the drive simple
and easy. Built-in torque rests
compensate for axial misalignment
of the encoder and drive, making a
compensating coupling unnecessary.
With hollow shaft encoders, the shaft and hub
connection is already integrated, but it is vital to mount the
encoder so that the correct torque is transmitted to the drive
shaft and not to the body of the encoder. Typically, hollow
shaft encoders are mounted in such a way that the weight of
the encoder is placed on the drive shaft, while a pin securing
the body of the encoder prevents it from rotating around the
drive shaft as torque is applied. Encoder motion should not be
restricted in any other way, as it could affect the accuracy of
the encoder.
Recessed hollow shaft encoders are identical in all ways to
standard hollow shaft encoders except that the hole is bored
only partly through the encoder housing. Mounting techniques
for recessed encoders are also the same.
Hollow shaft encoder
Recessed hollow shaft encoder
Advantages of hollow shaft encoders:
• Simple mounting
• Quick installation