The Study On Tracking And Measuring Non-circular Gear Of Polar Coordinates

Section curve of non-circular gear is designed in accordance with requirements of the Transmission ratio function, it combines the advantages of the cam and gears, which can achieve that the cam transmit with variable speed and gears transmit with high precision. Thus, non-circular gears in the Variable transmission occasions such as the machine tool industry, light industry automatic machinery, equipment manufacturing ,and so on , which has a very widely used. However, the research on the geometric precision, such as the shape of error detection, error analysis technique, few have studied on current at home. Currently, generally methods of single- flank engagement and double flank engagement are adopted as the measurement of non-circular gear ,for one, method of single-flank engagement requires a standard and high precision gear which machining with difficulty, in addition, it is complex. for another, method of double flank engagement can only be measured radial error ,which is difficult to reflect the error of the gear accurately. In this paper, taking polar coordinate measuring principle as the theoretical foundation, Using polar coordinates tangential tracking technology ,it designed non-circular gear measuring instrument based on DSP (digital signal processor) and FPGA (field programmable gate array) of data acquisition and control system. Which can track non-circular gear tooth profile continually and automatically ,to realize the measurement and overall evaluation of non-circular gear error.In this paper, the main content of the research is included :1. Method of non-circular gear polar coordinates tracking and measuring is proposed. probe scans gear constantly. the total deviation of the gear tooth profile, tooth pitch error, pitch error accumulation are measured2. A special case of non-circular gear, which is eccentric gear. realizing polar coordinates tracking and measuring, calculating the error of the eccentric gear and analyzing eccentric gear tooth profile features3. Proposed the thought on oval gear tooth of the hypothetical profile, took the hypothetical profile as the theoretical tooth, realized tracking measurement. Resolved interference problems between probe and the tooth profile, calculated normal deviation of the sampling point by taking the hypothetical profile as the benchmark, analysis the variation of the oval gears. Proposed method of equal arc length and unequal corner, calculated Pitch Error of non-circular gears.4. Proposed the ideas of "zero" tracking, measured cycloid gear, proved the accuracy of the "zero" tracking ideas according to the experimental data.5. Designed polar coordinate control system of non-circular gear based on DSP and FPGA, mainly including the servo motor control electric circuit, raster signal acquisition circuit, AD converter circuit, data communicating circuits and protecting circuits. Completed the PCB board manufacture, debugging of hardware and programming of software, used equal time principles to realize two axis linkages, has realized the non-round gear's tracking circuits measuring.