The invention relates to a method and a
system for selecting and measuring driving gear mounting distance adjusting shims of a driving gear pair and a driven gear pair in a
core component, namely an up-and-down split-type main
reducer assembly of an automobile driving bridge
assembly. The selecting and measuring
system comprises an online monitoring first detection
station, a second detection
station of a driving gear bearing pedestal subassembly, and an
electronic control system, wherein the first detection
station is a displacement sensing detection station of
axial data of a main differential case and adopts a displacement station device which is shifted to an online follower fixture; the second detection station is a displacement sensing detection station of
axial data of a driving gear inner bearing, a driving gear outer bearing and a driving gear bearing pedestal; and the
electronic control system obtains corresponding data values respectively through acquisition and conversion of an
axial data signal acquisition channel of the main differential case and an axial
data signal acquisition channel of a driving gear bearing pedestal
assembly, and obtains the thickness Ln of the driving gear mounting distance adjusting shims by calculation through a determined mathematic model. The technical proposal realizes online monitoring in a real sense, simultaneously suppresses interference of personal factors, reduces the measuring variation, and improves the measuring precision.