Technical Background of RV Reducers for Foreign Robots

: Foreign companies primarily focused on the research, development, and production of industrial robots include Sweden's ABB Industrial Robots, Germany's KUKA, and Japan's FANUC, among others. The joint drive transmission mechanisms in these companies' robot products mainly use RV reducers produced by Japan's Teijin. Because industrial robot drive mechanisms require high precision during transmission, small backlash (i.e., small return difference), robot maintenance, high rigidity, high output torque, and a large reduction ratio, commonly used transmission devices include: RV reducers, harmonic reducers, cycloidal pinwheel planetary reducers, and certain high-precision planetary reducers and other small-backlash precision control reducers.

High-performance precision control transmission is a key technology in the development process of mechanical transmission in modern industry. In recent years, it has received widespread attention and high importance. Japanese manufacturing enterprises refer to it as high-rigidity, high-precision RV transmission, which is a new type of precision transmission product that has emerged in recent years. In the early 1980s, Japan's Teijin Company began researching and developing the 2K-V cycloidal planetary pinwheel reducer, naming it RV transmission (Rotate Vector). Teijin Company started research on the RV reducer in 1986, achieved phased results, Zhonghengbiao Machinery, and completed industrial production. Since entering the market, this reducer has received widespread positive feedback due to its good performance. The company's high-rigidity, high-strength, high-precision RV reducers have now expanded into a complete series of products. The angular error of Japan's Teijin industrial robot reducers exhibits periodic changes. Its period is. Simultaneously, its speed ratio also changes periodically. This results in a phenomenon of ambient vibration on the output shaft.

Blanche also used some geometric methods to study the transmission accuracy of cycloidal planetary structure reducers. The theoretical analysis is relatively rigorous, and the results have considerable reference value. However, there are also some shortcomings. For example, during the research process, only the transmission accuracy of single-stage, single-piece cycloidal gear structure reducers was considered. The influence of the transmission accuracy of the now widely used multi-stage, multi-piece cycloidal wheel, multi-crankshaft structures was not considered. In the error analysis, only the influence of the pin tooth diameter and the relationship of parameters on rotational error and torsional vibration were considered. However, the structure of dual-stage, multi-piece cycloidal gears, and multiple crankshafts was not considered. Using this geometric method for calculation is relatively difficult.

Subsequently, Japanese researcher Teruaki Hidaka began research in this area. It mainly considered multi-stage transmission, multi-cycloidal gear transmission, and multi-crankshaft structures. An equivalent mass-spring model theory was adopted. A mathematical model for the rotational transmission error of the cycloidal planetary gear structure was constructed. Based on this theory, the influence of machining errors of main components, the influence of assembly errors, and the influence of clearance/backlash on rotational accuracy were discussed. However, this analysis only considered the no-load condition. Moreover, the analysis was of the influence of static rotational error. Factors such as internal bearing clearance and load fluctuations on dynamic rotational error were not considered.

Archive Number: 6654. Content organized from the old site database.