Design method of circular-elliptical-noncircular three-wheel synchronous belt transmission

Abstract

The invention discloses a circular-elliptical-non-circular tricycle synchronous belt drive design method. The method disclosed by the invention comprises the following steps: firstly, establishing a pitch curve equation of driving and driven wheels of the synchronous belt and calculating the transmission ratio of the driving and driven wheels by means of a polar coordinate theory; and then calculating the perimeter of the synchronous belt, and calculating a free pitch curve of a non-circular tension synchronous belt by means of an iterative algorithm according to the amount of looseness of the perimeter of the synchronous belt, wherein the tension wheel is a non-circular synchronous belt wheel with the free pitch curve, and the loosening variable of the synchronous belt generated in a driving process can be compensated in real time, so that the problem that a conventional two-wheel non-circular belt drive cannot meet non-uniform velocity drive and real-time tensioning at the same is solved; the radius of a circular driving synchronous belt wheel pitch curve and the long axis and eccentricity of the elliptical driven synchronous belt wheel pitch curve are adjustable variables, and the shapes of the circular driving wheel pitch curve and the elliptical driven wheel pitch curve are changed by adjusting the three variables, so that a special non-uniform velocity driving demand with a great center distance is met.

Description

technical field [0001] The invention relates to a design method of a non-circular synchronous belt transmission, in particular to a design method of a circular-elliptical-noncircular three-wheel synchronous belt transmission with variable slack self-compensation. Background technique [0002] The transmission mechanism changes the motion form and speed of the input and output components to meet the requirements of different working environments. Among them, the non-uniform transmission mechanism occupies a very important position, and the common ones are the connecting rod mechanism, the cam mechanism, and the non-circular gear mechanism. Compared with the connecting rod mechanism and the cam mechanism, the non-circular gear mechanism has the advantages of compact structure, stable transmission, large transmission power, and easy dynamic balance. Therefore, it has been successfully used in processing machine tools, automatic machinery, transportation, instrumentation, pumps, ...

AI Technical Summary

Problems solved by technology

However, non-circular gear transmission is only suitable for non-uniform speed transmission occasions with small center distance and convenient lubrication, so non-circular flexible member (belt / chain) transmission suitable for large center distance, inconvenient lubrication and low manufacturing cost should be used born

Among them, the polygonal effect of non-circular chain transmission is obvious, so it is limited when there are strict requirements on the change law of non-uniform transmission ratio; at the same time, ordinary friction belt transmission cannot guarantee accurate transmission ratio law due to elastic sliding.

[0003] The current non-circular belt (chain) transmission has only 2 non-circular belt (chain) wheels - the driving wheel and the driven wheel. During the transmission process, because the pitch curve is non-circular, the slack of the belt (chain) is real-time. Therefore, it is impossible to guarantee the non-uniform transmission ratio change law and the real-time tension of the belt (chain) required by the work at the same time.

In practical application, in order to compensate the slack change of the belt (chain) in the transmission, the tension is realized by adding a spring, because the tension force changes in a movement cycle, and the tension force increases with the aggravation of the non-uniform velocity characteristic. The greater the range of change, this will in turn affect the accuracy of non-uniform speed transmission, and the dynamic characteristics will become worse; therefore, in actual engineering, non-circular belt (chain) transmission is rarely used in precise load high-speed transmission occasions

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