Automobile part EOL test limit value formulating method

Abstract

The invention discloses an automobile part EOL test limit value formulating method, which comprises the following steps of: installing a part to be tested on a whole vehicle, and selecting a detection point in the whole vehicle; acquiring a vibration sound transmission frequency response function of the part from a mounting point on the whole vehicle to the detection point in the vehicle through a hammering test by utilizing noise vibration test equipment, taking dB as a coordinate of a response value, and drawing a VTNTF function curve; calculating the difference value between the maximum value and the minimum value of the VTNTF function curve and dividing the difference value into M equal parts, then dividing points on the VTNTF function curve into M equal parts, weighting the response values of the points on the VTNTF function curve according to intervals, then normalizing the VTNTF curve, namely VTNTF-RE / max, and recording the curve as VTNTF-RE-F; and selecting parts which can be critically accepted on the whole vehicle to perform retest on EOL, performing Fourier transform to obtain a frequency domain curve, multiplying the frequency domain curve by the VTNTF-RE-F curve, and performing weighted calculation to obtain a limit value curve in a whole frequency spectrum. An EOL limit value is comprehensively formulated for a whole perceptible sound frequency band.

Description

technical field [0001] The invention belongs to the technical field of off-line detection methods for auto parts, and more specifically relates to a method for formulating EOL test limits for auto parts. Background technique [0002] The auto parts EOL testing machine is mainly used for the quality inspection of key auto parts (such as engines, gearboxes, gearboxes, motors, etc.) Fixed evaluation limits (need to be approved by customers) are used as indicators to evaluate whether they are qualified or not, but the performance of key auto parts installed on the vehicle has a strong correlation with the structure, strength, and acoustic scheme of the vehicle , but the EOL test evaluation limit does not take these influences into account. The traditional EOL limit cannot comprehensively consider the performance of the part in the whole vehicle's perceivable sound frequency range (20-2000Hz), so it is impossible to formulate a comprehensive and comprehensive limit. , It is easy...

AI Technical Summary

Problems solved by technology

[0002] The auto parts EOL testing machine is mainly used for the quality inspection of key auto parts (such as engines, gearboxes, gearboxes, motors, etc.) Fixed evaluation limits (need to be approved by customers) are used as indicators to evaluate whether they are qualified or not, but the performance of key auto parts installed on the vehicle has a strong correlation with the structure, strength, and acoustic scheme of the vehicle , but the EOL test evaluation limit does not take these influences into account. The traditional EOL limit cannot comprehensively consider the performance of the part in the whole vehicle's perceivable sound frequency range (20-2000Hz), so it is impossible to formulate a comprehensive and comprehensive limit. , it is easy to cause some uncritical frequency bands to be too strict, affecting the production qualification rate of parts, and the key frequency bands are relatively loose, so the correlation between the test value of parts on EOL and the whole vehicle is relatively poor

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