Robotic Joint Design with Frameless Motors

In humanoid robotics, movement is everything. The fluidity, speed, and precision of robotic joint design determines the functionality and effectiveness of your robot. But achieving human-like movement in a compact space is a complex engineering puzzle.

Minebea’s Frameless BLDC motors offer a reliable modular solution. These motors provide powerful torque and efficiency in a form factor that’s optimized for robotic integration. Unlike traditional BLDC motors, frameless designs lack an outer casing, allowing engineers the desired flexibility for direct integration into their joint assemblies embed the stator and rotor into their joint assemblies.

Power and Precision in One Package

Our frameless BLDC motors deliver some of the highest power density in the market — critical for humanoid designs where every gram matters. Whether you’re designing elbow actuators, ankle pivots, or neck rotations, frameless motors give you the freedom to achieve compact designs without sacrificing performance.

Design Benefits for Robotics Engineers

These motors offer lower costs, better reliability and higher performance back-drivability and precise control—traits essential for robotic joint design that must mimic human dexterity. For robotic arms used in object manipulation or for bipedal locomotion systems, smooth and repeatable motion is critical.

Engineers can optimize joint configuration by placing the motor directly within the pivot point, simplifying mechanical linkage design and improving balance. And with a wide range of stator-rotor combinations, customization becomes straightforward.

Their low cogging characteristics enable exceptionally smooth motion at low speeds, reducing jitter and enhancing fine motor control—especially important for applications requiring delicate interaction or coordinated multi-joint movement

As a solution provider, our capabilities and offering extend beyond just the rotor-stator kits with possible integration of safety brakes, encoders, gearboxes and torque sensors to offer a turnkey solution which are a staple requirement for high torque robotic needs.

Key Use Cases

• Elbow and shoulder rotation
• Robotic knee actuators for walking and running
• Compact spinal joints for torso movement
• Dynamic head articulation in humanoid facial expressions

Our Frameless BLDC motors offer unmatched versatility and power in a form that supports the ambitious requirements of humanoid robot design. Whether you’re optimizing joint density, torque output, or mechanical simplicity, frameless motors are the key to enabling truly human-like movement.