Design method of circular-eccentric circle-noncircular three-wheel synchronous belt transmission

Abstract

The invention discloses a design method for synchronous belt transmission of a circular wheel, an eccentric circular wheel and a non-circular wheel. The design method disclosed by the invention comprises the following steps: establishing a pitch curve equation of a drive wheel and a driven wheel of the synchronous belt, and calculating the transmission ratio of the drive wheel and the driven wheel by virtue of tangential polar coordinate theoretical calculation at first; and then calculating the perimeter of the synchronous belt, and obtaining a pitch curve of a non-circular tensioning synchronous belt wheel through an iterative algorithm and according to the slack quantity of the perimeter of the synchronous belt. The invention further discloses a generation method for the tooth profile of the non-circular synchronous belt wheel. A tensioning wheel is a non-circular synchronous belt wheel with a free pitch curve, and capable of compensating the slack variation quantity of the synchronous belt, which is generated during a transmission process, in real time, and overcoming the problem that traditional two-wheel non-circular belt transmission cannot meet non-constant-speed transmission and real-time tensioning simultaneously; and the radius of the pitch curve of the circular drive wheel, and the radius and the eccentric distance of the pitch curve of the eccentric circular driven wheel are adjustable quantities, and the shapes of the pitch curves of the drive wheel and the driven wheel can be changed through adjustment for the three quantities, so that specific non-constant-speed transmission with a large centre distance is met.

Description

technical field [0001] The invention relates to a design method of a noncircular synchronous belt transmission, in particular to a design method of a circular-eccentric circle-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, pu...

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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