Bearing and shaft fit tolerance standard

Bearing and shaft fit tolerance standard

①When the bearing inner diameter tolerance zone and the shaft tolerance zone form a fit, the tolerance code originally belonging to the transition fit in the general basic hole system will become an over-win fit, such as k5, k6, m5, m6, n6, etc., but the over-win amount is not Large; when the bearing inner diameter tolerance is matched with h5, h6, g5, g6, etc., it is not a clearance but an over-win fit.

②Because the tolerance value of the bearing outer diameter tolerance zone is different from that of the general reference shaft, it is also a special tolerance zone. In most cases, the outer ring is fixed in the housing hole, and some bearing components require adjustments due to their structural requirements. Too tight, often with H6, H7, J6, J7, Js6, Js7, etc.

Attachment: Under normal circumstances, the axis is generally marked with 0~+0.005. If it is not often disassembled, it is an interference fit of +0.005~+0.01. If you need to disassemble and assemble frequently, it is just a transition fit. We also need to consider the thermal expansion of the shaft material itself when it is rotating, so the larger the bearing, the best clearance fit is -0.005 to 0, and the maximum clearance fit should not exceed 0.01.

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