Machine parts bearing design with how to choose, when assembled what should pay attention to?

Tolerance and shaft hole with the size and composition of the tolerance position tolerances. The size of the hole and shaft tolerances indicate with precision bore and shaft. Hole and shaft tolerance zones with the size and position expressed with precision and with the nature of the hole and shaft. With size tolerance = Tolerance band size; with bearing company with the size and position tolerance = with nature.
[Edit this paragraph] with the level of tolerance and tolerance
Tolerance level of choice
And bearing with the tolerance level of the shaft or housing bore and the precision of the bearing. And P0 level precision bearing with the shaft, the tolerance level is generally IT6, the housing bore is generally IT7. Rotation accuracy and smooth operation with higher requirements for construction machinery bearings occasions (such as motors, etc.), select the shaft bearings should be selected for the IT5, bearing holes IT6.
Select the tolerance band
Equivalent radial load P is divided into "light" situations "normal" and "heavy" load, etc., with the bearing of the dynamic load rating of C relationship is: light load P≤0.06C normal load 0.06C <P≤ 0.12C heavy load 0.12C <P
1) The shaft tolerance
Mounting tolerances radial bearings and angular contact bearings the shaft tolerance zone with reference to the corresponding table. For most occasions, the axis of rotation and the radial load direction unchanged, that the bearing inner ring with respect to the load direction of rotation of the occasion, the general should choose a transition or interference fit. Stationary shaft and radial load direction unchanged, that the bearing inner ring with respect to the load direction is static, choose a transition or small clearance fit (too large a gap is not allowed).
2) shell hole tolerance zone
Install radial bearings and angular contact bearings with reference to the corresponding housing bore tolerance tolerance zone table. Note For load direction oscillating or rotating outer ring selection, clearance fit should be avoided. Equivalent radial load with the choice also affects the size of the outer ring.
3) bearing structure in the form of seat selection
Rolling bearing unless there are special needs, and more generally with the overall structure, split bearing only on the mounting difficulties, or in the assembly on the advantages of easy to become main consideration when used, but it can not be applied to a tight fit or a more precise fit, for example, than K7 K7 and tighter fit, and if the tolerance class IT6 or more sophisticated housing bore, shall adopt split housings.
Tolerances standard bearing and shaft
① When the bearing bore and shaft tolerance tolerance constitute mating, formerly code-named transition fit tolerances in the hole basis system in general will change over to win with such k5, k6, m5, m6, n6 and so on, but the amount had not won Great; when the bearing bore tolerance generations and h5, h6, g5, g6 like fit, the gap does not become over-win cooperation.
② bearing diameter tolerance band due to the tolerance value is different from the reference axis, the tolerance zone is a special, mostly the case, the outer ring mounted in the housing bore is fixed, some bearing parts of the structure requirements and needs to be adjusted, it should cooperate tight, often with the H6, H7, J6, J7, Js6, Js7 like.
Attached
Under normal circumstances, the shaft is generally from 0 to + 0.005 standard if it is not often split, then, is + 0.005 + 0.01 interference fit on it, if disassembly is often transition fit on it. We also take into account the rotation of the shaft material itself when the thermal expansion, so the larger the bearing, it is best to fit the gap -0.005 to 0, and do not exceed the maximum gap of 0.01 fit. There is a dynamic interference, static ring gap.