Why Is The Actual Size Of CSB-EPB® Plastic Plain Bearings Larger Than The Size In The Catalog?

Why is the actual size of CSB-EPB® plastic plain bearings larger than the size in the catalog?

CSB-EPB® plastic plain bearings assembly is designed for interference assembly. In the free state, the measured inner diameter of the plastic bearing is greater than the standard inner diameter value in the product catalog. After the bearing is pressed into the standard H7 seat hole, the inner diameter of the bearing will be reduced. The detection of the inner diameter of the bearing is completed under the condition of being installed in the seat hole. Measured in the non-assembled state, the outer diameter and inner diameter of the plastic bearing are larger than in the installed state, which is mainly to prevent the plastic bearing from falling off during use. If there are still differences and problems in the installation dimensions and tolerances of plastic bearings, the possible reasons are:

There is no proper chamfering or smooth transition in the installation hole----the outside of the bearing is scratched and reduced the thickness of the bearing wall during installation. It makes the size of the inner hole of bearing larger after pressing.

The housing bore does not meet the H7 standard tolerance----the inner diameter of bearing after press-fit will change along with the diameter of installation housing.

The housing hole is made of soft material----the housing hole will be expanded after the bearing is pressed in. It makes the inner diameter of the bearing larger.