しまりばめの研究(第1報)

真円度の影響

抄録

As the factors which make difference between theoretical tightness of fit and actual one, measuring error, out of roundness, out of cylinderness and roughness of fitting surface, etc. are presumed.
In this report, how contact pressure, tightness, ratio of contact, etc. are effected by out of roundness of circular profiles of shaft and ring as a pair is studied.
In order to express skewness of circular profiles of the parts, the authors use radial length of "overlap" of both skew circle with same mean circles.
As the results of experiments, the authors find the followings.
1. Actual tightening pressure is generally higher than theoretical one. And twisting resistance varies according to change of setting angle phase between both parts, but it is equal to the product of thrusting resistance in the correspondent position and radius of the shaft.
These facts show that skewness of both circular profiles plays important role in fitting.
Skew profile of the shaft comes out to external profile of the ring according to thickness of the ring and interference.
In case that fitting is repeated, interference and out of roundness of the ring gradually Teduce and settle to some amounts.
Then the correlations of some degree are found among length of "overlap", thrusting resistance and ratio of contact.
As the ratio of contact is unexpectedly small, wearing, stick slip may easily be caused at the contacting points. Therefore attention must be given to lubrication of the fitting surface.