Car Main Reducer Assembly Transmission Error Measurement

As an important part in automobile drive axle, final drive is a primary source of vehicle noise, and its quality relates to transmission performance of vehicle. Various errors in production and assembly process will increase messing noise and reduce the transmission stability in hypoid gears. These errors case transmission error (TE) in final drive. In this paper, a method to deal with TE and realization in a measurement system on assembly line is introduced, and this research provides a new instrument for improve the quality of final drive.Base on the transmission chain of final drive, and messing theory of hypoid gears, primary sources of TE and the effect on quality are analyzed; a scheme which is based on spatial signal processing for TE measurement is proposed and proved. In this system, three angle displacement signals which are obtained from driving gear, left and right axle shaft via precise rotary encoder, are processed synchronously with FPGA device. By means of interpolation, angle displacement functions are approximately recovered from discrete signal data. Background noise in TE signal is decreased, desired is signal extracted with wavelet filter.The research developed a multi-path parallel signal acquisition card which is based on FPGA chip, and Verilog HDL is used to design logic actions. The card sends collected signals to computer through USB bus. Computer-based software system is designed with LabVIEW, including functions of signal acquisition and storage, data interpolation, wavelet filtering, signal graphic display. Calibration of the card by experiment shows that the measurement results accord with operating requirements. Finally, TE signal differences between qualified product and typical faulty product are compared and analyzed. According to experience and existing evaluation technology, correctness of this TE measurement system is proved.As an important measuring function in synthetic testing equipment of automobile final drive, TE measurement system has been applied in final drive assembling line. This new method provides new evaluation criteria in products quality control, and offers an effective way for manufacturing and assembling system. It is also in favor of reducing products reworking rate and reducing cost.