The fixed form of bearing is the different movement of rolling bearing, the specific fixed form has the following aspects.
I. Bearing fixed form:
There are three main forms of bearing fixation. 1. 2. One end is fixed and one end swims; 3. Swimming at both ends.
1. Fixed at both ends
The short shaft (span <400mm) at ordinary operating temperature can be selected in a simpler form with both ends fixed in one direction.
The fixed supports at both ends are generally composed of angular contact ball bearings or tapered roller bearings arranged symmetrically. When installed, adjust a ring of the bearing axially until a suitable clearance or the required preload is obtained.
2, one end fixed, one end swimming
When the shaft is longer or the working temperature is higher, due to the large expansion, it is appropriate to choose a fixed end, end swimming form, in order to ensure the free expansion of the shaft. (It can eliminate the adverse effects and damages caused by thermal expansion and cold contraction.)
Due to the manufacturing error, the center distance of the shaft supported by two radial bearings and the center distance of the bearing seat are usually not exactly equal, and the increase of working temperature will also change the distance, so the traveling bearing is needed to compensate for this error.
N type and NU type cylindrical roller bearings are ideal swimming bearings whose rollers and retainers can be moved in raceways within the bearing's non-baffle ring. Other types of bearings, such as deep groove ball bearings and self-aligning roller bearings, are used only when a ring is loose.
3. Swimming at both ends
It is an economical method to select two ends of swimming support on an axis which does not need tight axial positioning.
For shafts that require left and right two-way swimming, the shafting structure with both ends swimming can be adopted, such as a pair of herringbone gear shafts. Due to the axial limiting effect, the inner and outer rings and axial fixation of the bearings should be designed to ensure that only one of the axes has a fixed axial position relative to the machine base, while the two bearings on the other axis must be swimming, in order to prevent the teeth stuck or the uneven force on both sides of the herringbone teeth. At this point both ends of the bearing are free from axial forces.
Deep groove ball bearings, self-aligning ball bearings and self-aligning roller bearings are most suitable for swimming bearings. The mating of one of the two rings (usually the outer ring) of these bearings permits axial movement. Tapered roller bearings and angular contact bearings are not suitable for swimming because they must be adjusted to ensure normal rotation.