shrink fits是啥意思啊，机械上面的术语~~~~最好给详细点解释，中文和英文都要

1.a tolerance is the total reliable variation in the size of a part.
2.Medium running fits are intended for higher running speeds or henvy journal stress or both .
3.light drive fits are those requiting lightassembly pressures and produce more or less permanent assemblies.
4.heavy drive fits are suitable for heavier steel parts or for shrink fits in middle sections.

5. two methods of designayting limit dimensions are considered as standard.one method is the maximum material method in which the large dimensions is placed above the smaller dimension for male parts,and the reverse is true for female parts.this method is well suited for small lot quantities because it is likely that the nachinist himself may check the dimensions of the parts .in so doing,he will be verifying initially the larger dimension of the male part and the smaller dimension of the female part.the other method is the maximum number method and is preferred by production snd qualtity co