Research On Tolerance Design Method For Key Components Of RV Reducer

Cycloidal pinwheel RV reducer is a kind of planetary transmission which has two reduction stages with high performance and precision.It has the advantages of large ratio,high power density,high torsional rigidity,small backlash,well precision,good impact resistance,long life and so on.So it occupies the vast majority of the precision reducers market in industrial robots' joints.In precision transmission,the RV reducer high requirements for backlash,and the tolerance design of its key components is a major difficulty in the development process.Setting the precision too high will bring difficulties to the machining and testing of the parts,which is not conducive to cost control.If the accuracy is set too low,the drive accuracy will not meet the expected requirements.Therefore,it is very important to study the general method to tolerance design of key components in RV reducer.The main works of this paper are as follows:1.Based on the transmission principle and structure of the RV reducer,it has established a mathematical model for the analysis of geometrical backlash of the RV reducer while considering the main error factors of the first-stage involute gear transmission and the second-stage cycloidal needle-wheel drive.The sensitivity of each factor of geometrical backlash is analyzed to find the error factors that have a great influence on the backlash.The types of random distributions and their digital characteristics obeyed by each error influencing factor are analyzed to provide a theoretical basis for tolerance design and verification.2.Taking into account the sensitivity of the part design parameters' error to the influence of the backlash,this paper has considered the ease of the parts based on the fuzzy analytic hierarchy process,and adopted the weight expressions of the geometric average construction sensitivity and processing difficulty.Based on fuzzy analytic hierarchy process,the tolerance design method of key components of RV reducer is used to initially distribute the tolerances of RV reducer transmission components.3.The objective function is the total cost of the tolerance and the cost sensitivity of the tolerance,which is composed of the processing cost and the quality loss function.A multi-objective tolerance optimization model of the key components of the RV reducer is established,and the tolerance is optimized based on the genetic algorithm.Then,Monte Carlo has been used to the optimized tolerance distribution results' backlash simulation,and it can verify the feasibility of the optimization results.4.Developed the software for tolerance design and optimization of key components of RV reducer.It was applied to the design of RV reducer and shortened the design time.The prototype of RV reducer was processed and its backlash was tested on the test station.So,the feasibility and practicality of the tolerance design method in this paper can be verified.