What Is A Micro Coreless Motor(hollow Cup Motor): And Application in Humanoid Robots

A coreless motor, also known as a hollow cup motor or corelessmotor, is a type of miniature servo direct current (DC) motor. It is named for its rotor design, which features a hollow cup-like structure, breaking through the traditional rotor structure of conventional motors. Unlike typical DC motors, which use iron-core rotors, the coreless motor employs a rotor made of a hollow cup-shaped coil, hence its name.

The coreless motor primarily consists of a stator, a rotor, and a commutator system. The stator, often made of permanent magnets or electromagnetic windings, serves as the external part of the motor. The rotor, on the other hand, is composed of a hollow cup-shaped winding without an iron core. This innovative rotor design eliminates the electrical losses caused by eddy currents in iron cores, significantly reducing the motor's weight and rotational inertia, and thus minimizing mechanical energy losses.

Coreless motors are characterized by their high energy conversion efficiency, rapid response, and stable operation. They typically have maximum efficiencies of over 70%, with some models achieving efficiencies as high as 90% or more. Their mechanical time constants are less than 28 milliseconds, and some can reach within 10 milliseconds, making them ideal for applications requiring fast startup and braking. Additionally, their rotational speed can be easily adjusted within the recommended operating range.

In the field of humanoid robots, coreless motors have become a popular choice due to their small size, typically not exceeding 40mm in diameter, and their high performance. These motors are particularly suited for the fingers, joints, and other narrow spaces in humanoid robots. Their high power density, fast response speed, and high-precision control capabilities make them ideal for driving the various motion joints of humanoid robots.

For instance, Tesla's Optimus robot employs coreless motors in its joints. The small size and light weight of these motors allow for more compact and agile robot designs. Their high energy conversion efficiency also means that humanoid robots can operate for longer periods with the same power source, enhancing their overall performance and reliability.

Moreover, coreless motors' ability to be directly connected to various transmission mechanisms and sensors further enhances their versatility in humanoid robots. They can be used in electric grippers, robotic arms, logistics shuttles, and other components, contributing to the robots' high degrees of freedom and precision control.

The demand for coreless motors is expected to grow significantly as humanoid robots become more commercialized and produced in larger quantities. With advancements in AI, machine vision, and other technologies, humanoid robots are poised to revolutionize various industries, and coreless motors will play a crucial role in their development.

In conclusion, coreless motors are high-performance miniature servo DC motors with innovative rotor designs. Their high efficiency, rapid response, and stable operation make them ideal for a wide range of applications, including humanoid robots. As technology progresses and demand for humanoid robots increases, coreless motors will continue to play a pivotal role in driving the development of these advanced robotic systems.