Depth of robot harmonic reducer
reducer

The reducer is the core component of the rotary actuator, which is divided into harmonic reducer, planetary reducer, and RV reducer. Humans often use the first two.

Harmonic reducers have small volume, light weight, and high precision, but their soft wheels have limited impact resistance, limited lifespan, and high cost. Although the precision of planetary reducers is limited, their load-bearing capacity and impact resistance are better than harmonics.

After optimization, RV reducers are expected to be used in humanoid joints in the future. RV reducers are mainly used in industrial robotic arms. Cycloid reducers are a type of RV reducer that uses the principle of meshing between the cycloid wheel and the needle teeth, inherently possessing high torque and impact resistance. Currently, they have been optimized by manufacturers to significantly reduce volume and improve accuracy.

The harmonic reducer is relatively simple in composition, consisting of a flexible wheel, a rigid wheel, and a wave generator. The transmission principle is the staggered motion between the flexible wheel and the rigid wheel.

The core of a harmonic reducer is the elastic deformation of the flexible wheel and the misaligned motion of the gear mesh. The transmission process involves using a wave generator to deform the flexible wheel, and the external teeth of the flexible wheel mesh with the internal teeth of the rigid wheel in sequence to achieve deceleration.  

The most common type is double wave transmission, where the flexible wheel has two fewer teeth than the rigid wheel, such as 200 teeth for the rigid wheel and 198 teeth for the flexible wheel. The motor drives the wave generator to rotate once, and the flexible wheel rotates 2/200 turns. Two teeth are misaligned in the opposite direction, resulting in a reduction ratio of 100. By adjusting the relative gear ratio between the flexible and rigid wheels, different decelerations can be achieved. Single pole transmission can reach 70-500, some devices can reach 1000, and multi-stage transmission can reach over 30000.

The key performance indicators of harmonic reducers include service life, transmission accuracy, transmission efficiency, stiffness, temperature rise, noise, etc. Hamernaco has the best performance in the industry, with a service life of over 10 years, high transmission stability, low noise and vibration, and strong impact resistance. However, most domestic manufacturers have a service life of 2-3 years, and there are problems such as noise and oil leakage under high temperature and high speed. Hamernaco is leading in material heat treatment, IH profile design, precision machining, lubrication technology, etc., with a global market share of about 50-60% and a high-end market share of over 70%.