Frequently Asked Questions About The Relationship Between Preload Loads When Using NTN Bearings

After the NTN bearing is pressed into the bearing, it should rotate flexibly without any sense of blockage. If there is obvious inflexibility in rotation, it indicates that the size of the shaft is too large and the tolerance should be lowered. If the NTN bearing is pressed into the shaft and there is an obvious “sand” feeling when turning it by hand, it may be that the tolerance of the shaft is too large or the roundness of the shaft is not good. Therefore, when controlling the tolerance of the shaft and the bearing chamber, the roundness must also be controlled.

Because NTN bearings are high-precision products, improper assembly can easily cause damage to the NTN bearing groove, resulting in bearing damage. The bearing should have a special mold during assembly, and it cannot be knocked at will. When pressing into the shaft, only a small circle can bear force, and when pressing a large circle, only a large circle can bear force. It is required to use air pressure or hydraulic pressure during assembly, and the upper and lower molds should be outside the horizontal state during press assembly. If there is any inclination, the bearing channel will be damaged due to force, and the NTN bearing will produce guiding noise.

The service life of NTN bearings is closely related to manufacturing, assembly and use, and every link must be done well to keep the bearings in the best operating condition and prolong the service life of the bearings.
The additional sealing device supported by the NTN bearing can effectively make the bearing work normally under the good premise of not being intruded by external dirt, but this additional sealing device will increase the axial dimension of the mechanical mechanism, which will bring great harm to the use and installation of the bearing. At the same time, the sealing performance of the additional sealing device is often affected by the machining accuracy and shape tolerance of the matching parts of the journal and the housing.

The seal can prevent the intrusion of foreign matter from the outside. Foreign matter entering the bearing, especially metal foreign matter, often causes abrasive wear on the working raceway of the bearing, affects the use accuracy of the bearing, shortens the service life of the bearing, and any foreign matter entering the NTN bearing Harmful gases and moisture will not only cause corrosion of bearing parts, but more seriously, such harmful media will affect the physical and chemical properties of NTN bearing lubricants, destroy the lubricating oil film, and accelerate the aging of lubricants. The sealing device can also play a role in preventing lubrication loss and reducing environmental pollution.

Generally, sealing is essential for NTN bearings. If a bearing is directly exposed to the working environment without any sealing device, it is very harmful.

NTN bearings have a certain internal clearance, but sometimes when the bearings are installed or used in paired bearing groups, preloads are often applied to the bearings to cause a certain pre-deformation between the moving body and the inner and outer rings, so as to achieve The required work purpose, at this time the NTN bearing will run under the condition of negative clearance. Negative clearance is one of the characteristics of rolling bearings, and any kind of sliding bearing must work with clearance.