The demand for driving humanoid robots is exploding, and domestic substitution is accelerating

The demand for driving humanoid robots is exploding, and domestic substitution is accelerating

Harmonic reducer is the core component of rotary actuator, consisting of flexible wheel, rigid wheel and wave generator. The transmission principle is the staggered motion between flexible wheel and rigid wheel. The core is the elastic deformation of flexible wheel and the staggered motion of gear meshing. The wave generator deforms the flexible wheel, and the external teeth of the flexible wheel mesh with the internal teeth of the rigid wheel to achieve deceleration. Its main function is to reduce the speed and increase the torque.

Comparative analysis with planetary gearbox and RV gearbox

Upstream: Materials (flexible wheels, rigid wheels, wave generator materials) and equipment (import dependence on slow wire cutting machines, gear hobbing machines, etc.)

Material: The wave generator is made of high-strength alloy steel (such as 40Cr alloy steel), which requires high strength and stiffness; The flexible wheel is made of 40Cr alloy steel (such as 40CrMoNiA and 40CrA), which requires high strength, high toughness, and good cutting performance; The rigid wheel is made of ductile iron or carbon steel, which requires sufficient strength and wear resistance. The material requirements for flexible wheels and flexible bearings are high, and there is a gap between domestic purification technology and Japan. There are impurities that affect fatigue performance, and currently it still relies on imports.

Equipment: The core equipment includes slow wire cutting machines, hobbing machines, hobbing machines, ultra precision grinding machines, and related testing equipment. There is a big gap between domestic equipment and overseas equipment, and the industry highly relies on overseas brands such as Germany and Japan, with a delivery cycle of about 10-12 months.

Midstream: Main manufacturers' production processes (mainly hobbing/hobbing processes) and technical barriers (tooth profile design, heat treatment, etc.)

Production process: Soft wheel hobbing+rigid wheel hobbing is the mainstream process, and slow wire cutting has high precision but low efficiency, used for sampling; High gear hobbing efficiency and low precision, used for flexible wheel machining; The efficiency and accuracy of gear hobbing are between the two, and it is used for machining rigid wheels. The assembly process is complex and cannot be fully automated, requiring precise adjustment and calibration, relying on experienced technicians.

Technical barriers: including material preparation (ultra pure steel smelting technology is required for flexible wheels and flexible bearings, and insufficient domestic impurity control affects the service life), tooth design (Hamernak IH tooth monopoly, domestic breakthrough through independent solutions such as P tooth and LS tooth, but there is still a gap between meshing efficiency and service life), production process (processing accuracy needs to be controlled within 1 micron, relying on imported high-precision equipment, and the process requires long-term experience accumulation).

Downstream: Differences in application scenarios between industrial robots (accounting for 83%) and humanoid robots

Industrial robots: In 2024, global sales of industrial robots reached nearly 550000 units, with each unit using 3+harmonics. This is the main application area of harmonic reducers, accounting for 83% of demand.

Humanoid robots: The rotary actuators mainly use harmonic reducers, and the Tesla Optimus body uses 14 rotary actuators (harmonic reducers)+14 linear actuators. In the future, the upper body joints of humanoid robots will gradually use harmonic reducers instead of planetary reducers. Overseas manufacturers, as shown in the figure, adopt a full harmonic solution.