Issues regarding the preloading of rolling bearings
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Regarding the preloading of rolling bearings, there are a few questions: is preloading necessary for all bearing installations? I’ve seen fitters install bearings without carrying out this step, for example when working with our 7314B bearings. Also, why do the books state that axial preloading should be used instead of radial preloading for bearing preloading? Although there is a functional relationship between axial and radial clearance, does this relationship still hold after preloading? After all, most of our pumps are horizontal pumps, right? One moment it says that the bearing needs clearance, and the next moment it says that pre-tensioning should be used to create a negative clearance. So why not simply avoid any clearance during production?
Due to the presence of clearance in rolling bearings, under load the inner and outer rings move relative to each other, which reduces the stiffness of the bearing. This leads to radial and axial vibrations of the shaft, affecting the precision and lifespan of the machine. To reduce such vibration, in high-precision and high-speed mechanical equipment, preloading is often used when installing rolling bearings. This involves applying a certain load to the bearings at the time of installation (radially or axially), thereby eliminating their initial clearance and causing elastic deformation in the bearing body as well as the inner and outer rings, which prevents relative movement between these rings during operation. Not all bearing installations require pre-tightening.
We, as fitters, usually leave an axial clearance of 0.1mm