Problems to be considered in combination design of needle roller bearings for automobiles
Problems to be Considered in Combination Design of Rolling Bearings 1. Bearing Fixation
After determining the type and type of bearings, it is necessary to design the combined structure of rolling bearings correctly so as to ensure the correct operation of bearings.
The combined structure design of the bearing includes:
1) Shafting support end structure;
2) the matching of bearings and related parts;
3) Lubrication and sealing of bearings;
4) Improve the stiffness of bearing system.
1. Fixation at both ends (unidirectional fixation at both ends)
When the pivot is used, the two ends are fixed in one direction, and each bearing bears the bearing force in one direction. Allow a small amount of thermal expansion when the shaft is working. When the bearing shaft is installed, there should be an axial clearance of 0.25mm-0.4mm (the clearance is very small, it is not necessary to draw on the structural drawing). The clearance is usually adjusted by gaskets or adjusting screw.
Features: Restrict the two-way movement of the axis. It is suitable for shafts with little change in working temperature.
Note: Considering the heating elongation, there is a compensation clearance C between the bearing cover and the outer end face, C = 0.2~0.3 mm.
2. Two-way fixation at one end and swimming at the other
When the bearing is longer or the working temperature is higher, the thermal expansion and shrinkage of the shaft is larger, so it is suitable to adopt the pivot structure with one end fixed and one end moving.
The fixed end is mainly the bi-directional axial force borne by a single bearing or a group of bearings, and the swimming end guarantees the free movement of the shaft when it expands and contracts. In order to avoid loosening and falling off, the internal range of the swimming bearing and the shaft are fixed in the direction. Cylindrical roller bearings are used as swimming fulcrum. The outer ring of the bearing needs to be fixed with the seat. The free expansion of the bearing is guaranteed by the swimming between the roller and the ring.