Liquid-Cooled Joint Actuators (Active Thermal Management)

关节液冷（主动散热）Advanced

Circulating coolant through a joint motor to carry away winding heat, so it can sustain high torque longer.

Liquid-cooled joints add cooling channels around a joint module's motor housing or stator, with a pump circulating coolant that carries heat generated by the windings and driver away to a radiator. A motor's heat generation is roughly proportional to the square of its current, and the torque it can sustain continuously is mainly limited by winding temperature, not by how much force the motor can deliver instantaneously; when air cooling or passive heat dissipation can't keep up, the joint has to derate itself or trigger overheat protection. Liquid cooling can meaningfully raise sustained torque, letting a humanoid robot carry heavy loads or sustain highly dynamic motion for longer. The trade-off is the added pump, tubing, and coolant, which increase weight, complexity, and the risk of a leak. Electric-vehicle drive motors are almost universally liquid-cooled, and humanoid robot joints are starting to borrow the same approach.

Also called: Liquid-Cooled Joint, Active Joint Cooling
Related: Motor Thermal Derating / Overheat Protection · Rated Torque · Peak Torque · Joint Actuator Module · Power Density (W/kg) · Torque Density
Sources: Water cooling - Wikipedia