FMK Frameless Motor for Humanoid/Collaborative/Quadruped Robots’ Arms and Legs- 50~85 mm Diameter

A decade ago, Kinco pioneered frameless torque motor technology for robotics.

Today, the FMK series represents our fourth-generation innovation, featuring an optimized stator welding process, improved stator roundness, and a minimized axial length—all while delivering superior performance to meet diverse customer requirements. Reliable, high-performance operation is guaranteed by the following features:

1. Full-size coverage (50-85 mm stator outer diameter, customizable)

2. Large hollow-bore and high split-ratio design

3. Lightweight and high torque density

4. Low temperature rise

5. Low noise & vibration

Technic innovations:

Comprehensive size coverage, with stator outer diameters ranging from 50 to 85 mm, the FMK series suits all joint types—waist, shoulder, elbow, and wrist. It offers the most complete specification range in the industry.

Process upgrades improved, stator welding and potting processes reduce motor weight and lower temperature rise, effectively addressing heat dissipation challenges in legged robots during prolonged operation.

Structural innovation: the high split ratio and large hollow bore provide greater flexibility for bearing layout, giving mechanical engineers more design freedom. A specialized design reduces the total module length by up to 40%.

Applications:

FMK frameless motors are widely used in:

Collaborative robots & dual-arm robots (J1–J6 joints).

Rotary joints of quadruped robots (for walking and running motion).

Flexible joints of humanoid robots.

More details and files

FAQs

Q1: What is included in the package?
The package includes one FMK frameless motor set, including the stator and rotor. Accessories such as encoder, housing, servo drive, power supply, gearbox and mounting tools are not included unless specified as a kit.

Q2: Is this product, for users without mechanical integration experience?
This product is intended for engineers and teams with motor integration, mechanical design, servo drive, and motor control experience. For users who need a ready-to-run actuator, an integrated servo motor or joint module is recommended.

Q3: Can this motor be used for humanoid robot joints?
Yes. FMK motors are designed for compact robot joint applications, including humanoid robot joints, robotic arms, quadruped robot joints, and custom rotary actuators. Final selection must be verified by torque, speed, thermal, mechanical, and control requirements.