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STOBER Hollow Bore Servo Motors

STOBER Hollow Bore Servo Motors

STOBER’s new generation of hollow bore motors are an ideal solution for passing cables and pipes through the motor. It is available as a direct drive or with gearing ratios of 3, 9, or 27:1.

The bore diameter can range from 28mm to 45mm. Its compact design will save you space and ensure machine design efficiency. Optional water or forced air cooling can be added for increased power.


  • • Compact – motor mounts directly to the gearbox, eliminating a motor coupling, coupling housing, adapter, or additional input seals and bearings.
  • • Dynamic – direct mounting reduces inertia up to 75%
  • • Hollow Bore – allow for media (power cables, pipes, hoses, etc.) to pass through the motor
  • • Flange Output – easy mounting and stable output bearing
  • • Powerful Torque and High Stiffness – handle applications where the motor is also moving


  • • Magnetic Brake
  • • Water or Forced Air Cooling: for higher rated power (approximately 35%
    torque increase) or at high ambient temperature.
  • • Manual handwheel – allows for manual low power adjustments and improve safety.

Coupling Options

A variety of coupling options are available with the EZ motor family. The flange coupling is the standard

Flange Coupling

Standard option.

Clamp Ring Coupling

with housing to protect coupling

Clamp Ring Coupling without housing

for more play in angular alignment and easier mounting


STOBER Hollow Bore Servo Motors Additional Links: