For the short shaft (span l < 400mm) under normal working temperature, the fulcrum is often fixed in one Simple Bearing Design direction at both ends, and each bearing bears axial force in one direction respectively.
In order to allow a small amount of thermal expansion when the shaft works, an axial clearance of 0.25mm-0.4mm shall be reserved during Simple Bearing Design bearing installation (the clearance is very small and does not need to be drawn on the structural drawing). The clearance is usually adjusted by shims or adjusting screws.
When the shaft is long or the working temperature is high, the thermal expansion and contraction of the shaft is large, and the fulcrum Simple Bearing Design structure with two-way fixation at one end and swimming at one end should be adopted.
The fixed end is subjected to two-way axial force by a single bearing or bearing group, while the swimming end ensures that the shaft can swim freely during expansion and contraction. In order to avoid Simple Bearing Design looseness, the inner ring of the traveling bearing shall be axially fixed with the shaft (circlip is often used).
When the cylindrical roller bearing is used as the traveling fulcrum, the outer ring of the bearing shall be axially fixed with the base, and the Simple Bearing Design free expansion and contraction of the shaft shall be ensured by the swimming between the roller and the ferrule.
For the shaft that can swim left and right, the shafting structure with swimming at both ends can be adopted. It is a high-speed driving shaft driven by herringbone gear. In Simple Bearing Design order to automatically compensate the error of helix angle on both sides of the gear tooth and make the gear tooth stress uniform,
it adopts a structure that allows a small amount of axial swimming on the left and right of the shaft system, so cylindrical roller bearings are Simple Bearing Design selected at both ends. The low-speed gear shafting meshed with it must be fixed at both ends so that both shafts can be axially positioned.
In order to ensure reliable positioning, the fillet radius R1 of the shaft shoulder must be less than the fillet radius r of the bearing. The height of the shaft shoulder is usually no more than 3 / 4 of the height of the inner Simple Bearing Design ring, which is too high to facilitate bearing disassembly.
The axial fixation of the bearing inner ring shall select the structure of shaft end retaining ring, round nut and shaft elastic retaining ring according to the axial load. The outer ring is fixed in the form of base hole end surface, elastic ring, pressing plate, end cover, etc.
When the number of loaded rolling elements changes, it will produce exciting vibration. When a radial load is loaded on a bearing, the number of loaded rolling elements will change during operation, which causes the offset of load direction. The resulting vibration is inevitable, but now the bearing vibration and noise seem to be reduced. Why?
The reason is that the current bearing adopts directional preloading in the design to reduce the load on all rolling elements, so as to reduce the vibration and noise. Although directional preloading is adopted, it can not completely solve the problems of vibration and noise. So, how to further reduce noise?
1. The excitation vibration between the excitation part and the resonance part is prevented.
2. Change the stiffness to change the critical frequency.
3. Remove critical excitation vibration.