The precision reducers used in industrial robots around the world are basically monopolized by Japan. In recent years, although there are also mass-produced RV reducers in China, few domestic robot companies have chosen them. At present, reducers in the Chinese market generally rely on imports. ▲Japanese Yaskawa robot slashes peas. As a traditional manufacturing power, the reducer products of Germany, Italy, Japan and other countries are in the leading position in the industry in terms of materials, design level, quality control, precision, power density, reliability and service life. Reducer is an intermediate device connecting the power source and the actuator in the field of mechanical transmission. Usually, it uses the small gear on the input shaft to mesh the large gear on the output shaft of the high-speed power of the motor and internal combustion engine to achieve the purpose of deceleration and transmit greater torque. Driven by the development of aerospace, robots and medical equipment, the demand for high-performance precision reducers with simple and compact structure, high transmission power, low noise and smooth transmission has increased. Among them, RV reducer and harmonic reducer are the two most important reducers in precision reducers. Precision reducer is a power transmission mechanism that uses a gear speed converter to reduce the number of revolutions of the motor to the desired number of revolutions and obtain a larger torque. ▲Nabtesco reducer
Currently, there are not many companies in the world that can provide large-scale and reliable precision reducer manufacturers. The vast majority of the market share is occupied by Japanese companies: Nabtesco's RV reducer accounts for about 60%, Harmonica's harmonic reducer accounts for about 15%, and Sumitomo Heavy Industries (SUMITOMO, the proportion is not found). Especially in the field of robotics, the application ratio is overwhelming.
▲Disassembling the internal structure of the precision reducerNabtesco (Nabtesco) is a merger of two Japanese companies, Teijin Seiki and Nabock (which produced Japan's first automatic door in 1956). As manufacturers of motion control systems and components, both companies have mastered high-end core technologies in their specific business areas and control a large market share.
As the world's largest manufacturer of precision cycloidal pinwheel reducers, Nabtesco produces high-performance reducers, hollow shaft reducers, and single-axis servo actuators and controllers. The precision equipment it produces has high torque, high rigidity and high overload and impact load resistance, as well as high precision and very low return clearance. It is widely used in industrial automation fields such as satellites, radar antennas, industrial robots, semiconductors and welding technology. ▲Precision reducers applied to various joints of industrial robots Japan Harmonic Drive Systems Inc. (HDSI for short) is a leading company in overall motion control. Its Harmonic Drive combined harmonic reducers are lightweight, small, gear-free, and have high torque capacity. They are widely used in various cutting-edge fields such as industrial robots, humanoid robots, semiconductor liquid crystal production equipment, photovoltaic equipment, optical instruments, and precision machine tools. ▲Internal structure of harmonic reducer
In order to cover the low reduction ratio field that harmonic reducers cannot do, HDSI products also involve precision planetary gearbox type harmonic reducers Harmonic Planetary. The unique inner ring gear deformation process can make the planetary gear mesh more tightly with it and eliminate backlash, achieving precision-level transmission errors.
▲ Harmonic Planetary Gears Harmonic drive reducer is a gear transmission system that uses a wave generator to make flexible gears produce controllable elastic deformation and mesh with rigid gears to transmit motion and power from the beginning. ▲ Harmonic Planetary Gears Japan's Sumitomo SUMITOMO is a construction machinery manufacturer under the Sumitomo Group, one of the world's top 500 companies with a history of more than 400 years. After Sumitomo products developed the first hydraulic excavator with its own technology in 1967, Sumitomo hydraulic excavators are now active all over the world.
▲Sumitomo reducer
Sumitomo reducers include various types of reducers, such as Sumitomo large helical gear reducers, Sumitomo planetary gear reducers, Sumitomo helical gear reducers, Sumitomo worm gear reducers, etc. The reduction ratio is large, the efficiency is high, the pin-tooth meshing system has sleeve rolling friction, the meshing surface has no relative sliding, and the primary reduction efficiency can reach 94%. 02As a pinnacle of the precision machinery industry, the technical threshold of the reducer is very high. The RV reducer is made entirely of high-precision components, and the gears mesh with each other, which puts forward extremely high requirements for material science, precision machining equipment, machining accuracy, assembly technology, and high-precision detection technology. Domestic enterprises mostly obtain data through reverse engineering for research and development, and they know what it is but don't know why it is. Therefore, although some domestic enterprises have made major breakthroughs in technology, there are difficulties in the research and development of domestic reducers in terms of precision retention, precision life and product life. Various difficulties lead to poor consistency of domestic reducers and low reproducibility between products. On the other hand, the equipment for processing and manufacturing reducer parts is very expensive. For example, the unit price of the Meigler surface grinder is nearly 10 million yuan in RMB. Without sufficient production support, the amortization cost of equipment is frighteningly high. The cost of domestic precision reducers is higher than that of foreign competitors, but the performance is worse than that of competitors. Of course, sales are not good, and it is impossible to achieve economies of scale and profitability. Without profitability and batches, there are not enough resources for technical improvement, exploration and research and development, and there is no way to form quality control, let alone improve technology and performance. There are two main types of reducers currently used in the field of robots, one is the RV reducer and the other is the harmonic reducer. In articulated robots, since the RV reducer has higher rigidity and rotation accuracy, the RV reducer is generally placed in heavy load positions such as the machine base, upper arm, shoulder, etc., while the harmonic reducer is placed in the forearm, wrist or hand. Japan has an absolute leading advantage in high-precision robot reducers. Currently, 75% of the precision reducers in the global robot industry are monopolized by Japan's Nabtesco and HarmonicDrive (commonly known as RV reducers and harmonic reducers in the industry), including reducers of international mainstream robot manufacturers such as ABB, FANUC, and KUKA are all provided by the above two companies. According to industry insiders, international mainstream robot manufacturers such as ABB, FANUC, Yaskawa, and KUKA are all provided with reducers by the above two Japanese companies, and have very harsh cooperation conditions with the two companies, that is, when using the products of these two companies, other products can no longer be used, otherwise the cooperation relationship will be terminated. Core components have always restricted the rapid development of Chinese robots. If we want to form the industrialization of robots, get rid of the constraints of foreign robot companies, and gain independence in the field of robots, we must accelerate the localization of reducers.
