Harmonic Drive

X-Ray Machine C-Beam Drive

Sub-assembly
Integrated output bearing

In medical equipment it is often essential that high reduction ratio gears are particularly quiet in operation. For this reason Harmonic Drive gears are applied in an increasing range of medical devices. This design example shows how an HFUC-2UH unit is used to drive the C-beam of an X-ray machine. The moveable C-beam is used to position the X-ray source precisely above the body of the patient.

In this case the complete C-beam sub-assembly, comprising the housing, DC servo motor, Harmonic Drive precision gear and absolute measuring system was designed and developed in close cooperation with the customer. A particularly interesting design feature is the use of an input shaft that passes through the flange bearing of the unit. In this application the flange is fixed and the housing of the unit, which incorporates the Circular Spline, is used as the rotating output element. A further feature is the use of a brake attached to the extended input shaft. This is used for safety reasons to hold the input to the gear, should the belt between motor and input shaft fail.