Interference、transition and clearance ，Do you really understand？

Three basic mating relationships in mechanical design: interference fit, transition fit, and clearance fit.

Many people consider the interference fit in the product design only when they are tighter. interference fit, transition fit, and clearance fit.

interference fit should notice:

1. When the interference fit shaft hole, must have a guiding function, that is, must have a chamfer

(the hole shaft must have a certain chamfer, that is, the chamfering of the two parts should be chamfer or a tapered surface that plays a guiding role) ;

2. There must a clear positioning mechanism between the interference fittings

(a shaft shoulder, a boss, etc. the interference fit ensure the depth product must design);

3. Avoid pressing too interference surfaces at the same time

(two interference mating surfaces are press at the same time or almost simultaneously, the assembly is very difficult, and it should be designed .so the other mating surfaces can  press one );

4. When the surface is mate, there must no positioning structure

(such as positioning on the end face, it may cause a gap between the two taper surfaces and lose the fit relationship);

When inserting interference fit into the blind hole.

the exhaust air should be considered. If a closed space is formed inside the hole,
It will be more difficult to pull out. Used small holes or inner grooves (while doing so can also facilitate mold release);

For deep interference fit on the same size axis, its insertion and removal are difficult. 

limit the length with interference to the necessary minimum size is necessary.easy insertion leaving a slight gap in other parts. In addition, if the machining axis is longer.

only the fitting relationship parts are accuracy designed to meet the requirements.

the other parts are larger or smaller according . and the structure, accuracy is lower so the processing control convenient 

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