[1] Size limitation. Generally, the space in which NSK bearings can be installed is limited. In most cases, the shaft diameter (or NSK bearing inner diameter) is based on mechanical design or other design constraints. Therefore, the choice of NSK bearing type and size is determined by the inner diameter of the NSK bearing. Therefore, the main size tables of standard NSK bearings are compiled according to the international standard inner diameter size.

    There are many sizes of standard NSK bearings. It is best to use standard NSK bearings in the design of mechanical devices. (This is to say whether NSK bearings are easy to purchase. Here is a digression. Some imported NSK bearing catalogs do have models, but Some non-standard NSK bearings are not available in mainland China, and sometimes the futures will take a long time. Therefore, the time cost and the cost of later replacement should be considered when selecting the NSK bearing. The load of the NSK bearing, the load imposed on the NSK bearing, Its nature, size and direction are changeable. Generally, the rated basic load is shown on the dimension table. But axial load and radial load, etc. are also important factors in choosing a suitable NSK bearing. When the size of the ball and needle roller bearing is commensurate, the needle roller bearing usually has a higher load capacity and can withstand greater vibration and shock loads.

    [2] The speed, the permitted speed is determined according to the NSK bearing type, size, accuracy, cage type, load, lubrication method, and cooling method. The NSK bearing table lists the permitted speeds of standard precision NSK bearings under oil lubrication and grease lubrication. Generally, deep groove ball bearings, self-aligning ball bearings and cylindrical roller bearings are suitable for high-speed operation.

    [3] NSK bearing tolerance, NSK bearing dimensional accuracy and rotation accuracy are based on ISO and JIS standards. For machinery that requires high precision and high-speed operation, it is recommended to use NSK bearings with accuracy of 5 or above. Deep groove ball bearings, radial thrust ball NSK bearings or cylindrical roller NSK bearings are suitable for machinery with high running accuracy. Rigidity. When the contact surface of the elastic body and the raceway of the NSK bearing is compressed, it will produce elastic deformation. Some machines need to minimize elastic deformation. Roller bearings produce smaller elastic deformations than ball NSK bearings.

    [4] In some cases, NSK bearings need to be preloaded to increase rigidity. This program is usually used for deep groove ball bearings, radial thrust ball bearings and tapered roller bearings to offset the inner and outer rings, shaft bending, shaft or NSK bearing housing tolerance changes, and matching errors will lead to eccentricity of the inner and outer rings. In order to prevent the eccentric angle from being too large, self-aligning ball bearings, self-aligning roller bearings, or self-aligning bearing seats are better choices. Voice frequency and torque, dynamic NSK bearings are manufactured according to high-precision standards, so the voice and torque are small. Deep groove ball bearings and cylindrical roller bearings are used together for occasions that have special requirements for low noise and low torque.

    [5] Installation and disassembly, some applications need to be disassembled and installed frequently to ensure that inspection and maintenance can be carried out according to the location. NSK bearings whose inner and outer rings can be installed separately, such as cylindrical bearings, needle roller bearings, and tapered bearings are very suitable for this occasion. The tapered hole type self-aligning ball bearing and self-aligning roller bearing, with the help of the sleeve, also simplify the installation procedure.
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    The internal clearance of the rolling bearing before installation is generally expressed by the theoretical clearance.

    The clearance after subtracting the expansion or contraction of the ring caused by the interference fit when the rolling bearing is installed on the shaft or in the housing is called the "installation clearance" from the theoretical clearance. The clearance obtained by adding or subtracting the dimensional change due to the internal temperature difference of the rolling bearing to the installation clearance is called the "effective clearance".

    The rolling bearing is installed with a mechanical clearance when it is placed under a certain load, that is, the effective clearance plus the elastic deformation caused by the rolling bearing load so as to be called "working clearance". 　

    When the working clearance is slightly negative, the fatigue life of the rolling bearing is the longest, but the fatigue life decreases significantly as the negative clearance increases. Therefore, when selecting the clearance of the rolling bearing, it is generally appropriate to make the working clearance zero or slightly positive.

    In addition, when the rigidity of the rolling bearing needs to be improved or the noise needs to be reduced, the working clearance should be further negative, and when the temperature of the rolling bearing rises sharply, the working clearance should be further positive. .