the bearing assembly must strictly control and adjust the clearance.

Bearing clearance is defined as a case of a fixed ring, another ring in the radial or axial flow by the maximum amount, the clearance is divided into radial clearance and axial clearance two kinds . Move needle bearing assembly, the clearance is not too big, not too small. Clearance is too large, it will cause the load to move the body to withstand the reduced number of individual load increases to move the body, thereby reducing the accuracy of rotation of the bearing, reducing the service life; clearance is too small, the friction will increase, the heat generated increases, increased wear, also can reduce bearing life. Therefore, the bearing assembly must strictly control and adjust the clearance.

Precision bearing temperature causes are: oil quality does not meet the requirements or deterioration, lubricant viscosity is too high; institutions assembly too tight (lack of space); bearing assembly tight; bearing ring on the shaft or housing rotation; overload Large; bearing cage or rolling fragmentation.

1), the shaft and housing bore roundness and the vertical shoulder block bearing according to the appropriate precision requirements.

2), it is necessary to accurately calculate the rotating rings fit the amount of interference, but also suitable for accurate calculation of the amount of the fixed ring. Rotating rings blanch the amount of interference to the extent possible should also get smaller. As long as the operating temperature and ensure the effect of thermal expansion, and the maximum speed of the centrifugal force, resulting in a tight fit so as not to creep or sliding surfaces. Fixed ring size according to the work load and bearing size, select small clearance fit or interference fit, too loose or too tight is not conducive to maintaining the original shape exactly.

3), needle roller bearings operating under conditions such as high speed, and high operating temperatures, special attention should be rotating rings can not be too loose to prevent eccentric, as well as non-fixed ferrule with a gap to prevent sleeve ring deformation under load and to stimulate vibrations.

Rolling in the work allow slight noise, if the noise is too large or unusual noise or crash, it indicates that the bearing has failed.

Preload is the bearing assembly to the inner or outer ring an axial force to remove the needle bearing clearance, and to move the body and the inner and outer contacts generated at the beginning of deformation. Preload can improve the working condition of the bearing stiffness and rotational accuracy, load bearing large, rotating high precision bearings, mostly in the absence of even a small amount of clearance over the work of state interference, in which case it required in the assembly, the bearing preload. Clearance and preload adjustment are usually seen by the inner ring relative axial displacement of appropriate methods to complete. From the above process is not difficult to learn concepts, through to move the bearing clearance adjustment, can improve the bearing capacity and rotation accuracy, progressive bearing life. But at the same time make the bearing frictions, fever increases, so the clearance or preload adjustment when necessary to ensure good lubrication and heat dissipation. If improperly adjusted or poor lubrication, it will in turn cause increased bearing wear, reduced life expectancy.