Clear bore
Size the usable opening for connectors and motion, not just the nominal shaft ID.
HOLLOW SHAFT / THROUGH BORE
Hollow-Shaft Pancake Motors
Route services through the axis while keeping axial height under control. Define the clear passage, shaft support and cable path as one mechanical envelope.
Send Us Your Space Constraints ↗
Before selecting a winding
Resolve the installed envelope first.
Cable exit
Check radial lead clearance and strain relief against the surrounding enclosure.
Support load
Separate motor torque from permitted axial, radial and moment loads.
Keep a real passage through the assembled axis
A hollow shaft is useful only if cables, tubing and connectors can pass through the installed mechanism. Include rotary travel, bend radius, protective sleeves and service access. For continuously rotating equipment, a slip ring or rotary union is a separate design decision.
Account for the bearing span before freezing thickness
A short motor body can still need a longer assembly to support an overhung load. Specify the shaft extension, load application point, bearing arrangement and runout target. Review flange faces and fastening access so the thin motor can actually be assembled and maintained.
Match feedback and cable routing to the motion requirement
Encoder location, connector orientation and electrical noise can constrain a through-bore arrangement. Identify the controller, feedback interface and shielding strategy early. Prototype inspection should include bore clearance, shaft runout, loaded temperature and motion repeatability in the receiving machine.
Questions before freezing the drawing
Is the whole nominal bore available for wiring?
Confirm the finished drawing. Sleeves, retaining parts, seals and feedback hardware can reduce the usable passage.
Can the motor support a robot joint load directly?
That depends on the selected bearing arrangement and load case. Motor torque alone does not establish structural load capacity.