Frameless torque & coreless motors
Motor rotor/stator sets built directly into joints; tiny coreless motors drive finger joints.
Data updated
Why it matters
Frameless torque motors are supplied as rotor and stator only so the robot maker can integrate them into a compact joint housing. Dexterous hands use many small coreless or brushless motors, about 20 per hand on an Optimus-class robot.
Why it is a bottleneck. Torque density and heat dissipation limit joint performance. High-performance motors depend on rare-earth (NdFeB) magnets, a supply largely controlled by China, and an Optimus-class robot carries 40+ servo motors.
Suppliers 5
- KollmorgenTBM2G frameless torque motors for robot joints
- Leadshine TechnologyFrameless motors, joint modules and dexterous grippers; servo drives
- TQ RoboDriveFrameless torque motor kits
- Tuopu GroupRotary actuators / joint modules; dexterous-hand motors
- maxonBrushless/coreless motors, gearheads and drives
Sources for this category
- Who builds the joints? The humanoid actuator supplier landscape in 2026 (humanoid.guide) (Sep 16, 2026)
- TBM2G frameless motors (Kollmorgen) (accessed Oct 8, 2026)