The Surprising Connection Between Reducers and Robots

ZR-ROBOT Zhongheng Biao Machinery Robot Repair News: Reducers are key components of robots, accounting for one-third of the total production cost of a robot. China started research on robot reducers relatively late, and the technology is immature. Currently, there is a heavy reliance on imports. Reducers are a key factor constraining the development of China's robot industry. Overcoming reducer technology is an inevitable choice for the industrialization of domestic robot enterprises.

Robot reducers can be divided into five categories based on their structure: harmonic gear reducers, cycloidal pinwheel planetary reducers, RV reducers, precision planetary reducers, and filter gear reducers. They differ in various performance indicators used to measure reducers, such as precision, torque, stiffness, and transmission efficiency. Among them, RV reducers and harmonic reducers are the most mainstream precision reducers for industrial robots.

Currently, the situation for Chinese robots remains severe, with the most typical issue being the lack of overall breakthroughs in core robot technologies. Core components are mainly divided into three parts: robot reducers, AC/DC servo motors, and controllers. In terms of cost, the current global robot industry cost structure is approximately 35% for reducers, 20% for servo motors, 15% for control systems, the mechanical processing body may only account for about 15%, with the rest primarily being applications.

Globally, only a very few countries can produce RV reducers. In recent years, although China also has mass-produced RV reducers, and product performance indicators can meet requirements in the short term, due to issues with quality control and processes, they are prone to wear and scrapping. Therefore, few domestic robot companies choose them, and the Chinese market still generally relies on imported reducers.

The technical difficulty of RV reducers lies in the need for the component to ensure the transmission of high torque, withstand significant overload impacts, and guarantee the expected service life. Consequently, an over-constrained structure is used in the design, which requires extremely high machining precision for the parts, making processing very difficult. A major constraint for their mass production is the processing equipment and techniques.

The gap between domestic RV reducers and foreign products is relatively small in terms of rated torque and transmission efficiency. However, the gap is still quite noticeable in stability and precision indicators such as torsional stiffness and transmission accuracy. Due to differences in materials and process levels, the gap in fatigue strength resistance is also relatively significant.

It is expected that the main development direction for domestic reducers in the near future will focus on technological breakthroughs and refinement. In terms of the market, they will first enter the mid-to-low-end industrial robot market and gradually enter high-end products such as welding robots for automotive production lines after 2016. The localization of reducers will significantly reduce the cost of domestic industrial robots.

Currently, domestic RV reducers still require improvements in materials, processes, fit, precision, wear resistance, materials, heat treatment, bearings, and other aspects.

Harmonic reducers are the core components for robots to achieve motion functions. They are indispensable for the reliable and precise operation of lightweight industrial robots and robotic arms. They allow the robot's servo motor to operate at a suitable speed and precisely reduce the speed to the levels required by various parts of the robot, while improving the mechanical body's rigidity and outputting greater torque. The composition of harmonic drive: only three basic components: a wave generator, consisting of an elliptical cam with a thin-walled ball bearing embedded on its outer circumference. The bearing inner ring is fixed on the cam, and the outer ring achieves elastic deformation through the balls. It is usually installed on the input shaft. A flexspline, a metal elastic body component with a thin-walled structure. Gears are machined on the outer circumference of the opening. It is usually installed on the output shaft. A circular spline, a rigid ring-shaped component. Gears are machined on the inner circumference, with two more teeth than the flexspline. It is usually fixed to the housing.

Domestic harmonic reducers have almost no significant gap with foreign reducers in terms of technology and other aspects, and even surpass the performance of foreign harmonic reducers in some areas.

Archive document number: 3599. Content organized from the old site database.