Hollow shaft incremental encoders mount directly onto the machine or motor shaft through a hollow bore, eliminating the separate flexible coupling required by solid shaft designs. A torque reaction arm or stator coupling prevents the encoder body from rotating while the shaft passes through. This direct mounting reduces installation time, eliminates a potential failure point, and allows a more compact overall drive assembly. Bore diameters range from 6mm to 50mm or larger, covering standard motor shaft dimensions across all common frame sizes. Output signals match solid shaft types: A/B quadrature channels with optional Z index, available in HTL, TTL/RS422, NPN/PNP, and SinCos formats with resolutions up to 10,000 PPR. Both clamping collar and press-fit shaft attachment variants are available. IP67 and IP68 sealed variants handle coolant, washdown, and dusty environments. Stainless steel housing versions suit corrosive or food-adjacent environments. For large bore applications such as crane drives or rolling mill shafts, heavy-duty hollow shaft variants with reinforced housings and higher shaft load ratings are available. Hollow shaft incremental encoders are specified where machine envelope is restricted and coupling alignment is difficult - printing machine roll drives, textile spindles, conveyor head pulleys, and machine tool auxiliary axes are typical installations. Their compact direct-mount design also reduces accumulated misalignment errors that can occur when coupling tolerances stack with shaft and housing tolerances in precision applications.
