Joints are one of the most important basic components of industrial robots and the core component of motion: precision reducers. This is a precision power transmission mechanism that uses a gear speed converter to reduce the motor's rotational speed to the desired speed while obtaining a larger torque, thereby reducing the rotational speed and increasing the torque.
The speed reduction transmission at the robot joints requires a short transmission chain, small size, high power, light weight, and easy control. At the same time, for industrial robots with medium to high loads, sufficient rigidity, rotational accuracy, and motion accuracy stability are also required.
Currently, there are only a few manufacturers worldwide capable of producing large-scale, reliable precision reducers. The vast majority of the market share is held by Japanese companies: Nabtesco's RV reducers account for approximately 60%, Harmonica's harmonic reducers for approximately 15%, and Sumitomo Heavy Industries (whose market share was not found). Their dominance is particularly pronounced in the robotics field.
▲Disassembling the internal structure of the precision reducer
Nabtesco was formed by the merger of two Japanese companies: Teijin Seiki and Nabtesco (which produced Japan's first automatic door in 1956). As manufacturers of motion control systems and components, both companies possessed advanced core technologies in their respective business areas and controlled a significant market share.
As the world's largest manufacturer of precision cycloidal pinwheel reducers, Nabtesco produces high-performance reducers, hollow shaft reducers, as well as single-axis servo actuators and controllers.
The precision equipment it produces has high torque, high rigidity and high resistance to overload impact loads, while also having high precision and very low backlash. It is widely used in industrial automation fields such as satellites, radar antennas, industrial robots, semiconductors and welding technology.
Harmonic Drive Systems Inc. (HDSI) of Japan is a leading company in overall motion control. Its Harmonic Drive combined harmonic reducers are characterized by their lightweight, compact size, zero gear backlash, and high torque capacity. They are widely used in various cutting-edge fields such as industrial robots, humanoid robots, semiconductor LCD production equipment, photovoltaic equipment, optical instruments, and precision machine tools.
To cover the low reduction ratio range that harmonic reducers cannot achieve, HDSI's product line also includes the precision planetary gearbox type harmonic reducer, Harmonic Planetary. A unique internal gear ring deformation process allows for tighter meshing of the planetary gears, eliminating backlash and achieving precision-level transmission accuracy.
Sumitomo is a construction machinery manufacturer under the Sumitomo Group, one of the world's top 500 companies with a history of over 400 years. Since Sumitomo developed and manufactured its first hydraulic excavator in 1967, Sumitomo hydraulic excavators have been active all over the world.
Sumitomo gearboxes include various models such as large helical gear reducers, planetary gear reducers, worm gear reducers, etc. They feature large reduction ratios, high efficiency, and a pin-tooth meshing system with rolling friction and no relative sliding on the meshing surfaces; single-stage reduction efficiency can reach 94%.
