А quantitative estimate of uncertainty of the random scattering of the average clearance and interference in mating

Abstract

Actual dimensions of suitable parts made according to
the same drawings can fluctuate between the given limit
dimensions, and the clearances and interferences in the
conjugations — depending on the random scattering
of the actual dimensions with the deviation of the shape
of the real surface or profile. The error of the shape of
the real surface affects the probabilistic estimate of the
results of sorting parts, leads to uncertainty in the size of
the maximum of the material, a random scattering of the
average clearance and interference in the mating and, as a
consequence — the uncertainty to use all that come in for
assembly of parts. The main result of the study is related
with ensuring the receipt for the assembly of an equal
number of parts, to the conclusion possessing novelty of the
analytical dependences of finding a quantitative estimate
of the uncertainty of the random scattering of the average
clearance and interference in the mating, the random
scattering of the average size relative to the upper and
lower acceptance boundaries. Using the assembly method
proposed with the initial reduction of real clearances and
interferences in the mating by means of narrowing the
tolerances of the actual dimensions to the tolerance of the
shape of real surfaces in diametric terms within the random
dispersion of the average size relative to the upper and
lower acceptance boundaries allows to ensure the receipt
on the assembly of an equal number of parts is achieved,
including in the tested batches of parts with a breakdown
of the tolerances of the actual dimensions into an equal
number of dimensional groups.