The precision of the rolling bearing with design

1, the rolling bearing coordinates system under normal circumstances, the rolling bearing cooperate when using base hole system, but if but for standard parts, with the combination of parts with the nature is determined by the standard. In terms of rolling bearings, because it is standard parts, to match the outer part adopts the basic shaft system, to match the inner ring of the shaft adopts the basic hole system. The coordination is the base of bearing inner ring on the shaft hole system, although the roller bearing inner ring all tolerance zone of tolerance grade below the zero line and the deviation is zero. The main reason is the special requirement of bearing fit. In most cases, the bearing inner hole with the axis of rotation, the fit between the two must have a certain interference. Figure 1 rolling bearing and shaft, shell with common tolerance note: a) Bearing and shaft with common tolerance zone diagram; b） Bearing and the shell with common tolerance zone diagram; ∆ DMP: for bearing inner ring of the single plane average diameter deviation; ∆ Dmp: for bearing outer ring of the single plane deviation of average diameter. 2, shaft, bearing fit tolerance levels of choice to match the rolling bearing of hole and shaft tolerance grade is closely related to the bearing tolerance level. Usually cooperate with/P6, / PO bearing shaft, its tolerance level for IT5 ~ IT7, casing hole are many IT6 ~ IT8, etc. 3, cooperate with the nature of the bearing with the nature of the selection is sure to match the bearing of the shaft neck and the basic deviation of the bearing. Bearing with the nature of the basis is: bearing type, inside and outside the circle of load bearing under the working conditions of load, the size of the bearing, to match the bearing hole and shaft materials and handling requirements, etc. 1) Load type low partial load: the synthesis of the radial load acting on the bearing and the relative static ring, namely the load direction is always the same in the ring groove on the local area. Usually use small clearance fit or transition fit. Low cycle load: the synthesis of the radial load acting on the bearing and the relative rotating ring, namely progressive role in synthesis of radial load on the ring of the circumference of a circle. Usually adopt interference or transition fit tighter. Swing low load: the synthesis of the radial load acting on the bearing and the bearing ring relative oscillation in some area, the synthesis of radial load change often, even in the ring groove on the part of less than 180 ° circumference of a circle. Figure 2 bearing inner and outer load type figure note: a inner ring cycle load, outer ring local load; B inner ring local load, outer circulation load; C inner ring cycle load, outer ring oscillating load; D inner ring oscillating load, outer cycle load. 2) Load bearing under the action of load, the size of the ring will occur deformation, make the fitting surface stress non-uniform, cause is loose. Accordingly, when handles the load match should be tight, at light load should be loose some. Generally, load the following categories: low light load: P 0 or less. 07C； Low normal load: 0. 07C