NTN bearing the preparing work before cooperate with installation and adjustment

1. NTN bearing and clearance with NTN bearing should be in accordance with the requirements of high precision bearings, and according to the requirements of high temperature bearing, so when considering its coordination and clearance, to consider the following two points: ( 1) From normal temperature to high temperature when the size of the change and hardness change; ( 2) Under the high speed centrifugal force caused by the force system and shape changes. All in all, under the condition of high speed, high temperature, from the choice of coordination and clearance to strive to maintain the accuracy and working performance of the bearing, it is difficult. To ensure the bearing raceway deformation after the installation is small, the amount of interference interference fit can't get too big, and under the high speed centrifugal force and high temperature thermal expansion, or on the surface of the offset with the normal pressure. Or make the matching surface relaxation, thus interference quantity must under the premise of considering these two factors determine prudently, effectively under the constant velocity of the amount of interference for NTN bearing may be invalid. Calculation result if the conflict is too big, Usually it happens only under ultra-high speed) , only take ring lubrication and hydrostatic lubrication and lubrication measures, and this scheme has the potential to hit the 3 million mark DMN value of the bearing. When considering NTN bearing clearance not only should consider the above-mentioned factors, and to consider the influence of the axial thermal elongation of clearance, bearing under working state, namely in the working temperature is the best clearance, clearance is, and this, the outer ring groove ball center accurate registration form of the condition. Because of the NTN bearing makes every effort to reduce the relative sliding and internal friction, had better not use relative displacement of the inner and outer ring along the axial approach to adjust clearance of ball bearings. Considering the amount of the interference with the bearing clearance, and be aware that materials at high temperature becomes soft and easy to deformation characteristics, and many times caused by the temperature change of normal temperature to high temperature must be the possibility of permanent deformation. 2. NTN bearing requirements of host related parts precision bearing in rotary system of dynamic balance, shaft and hole bearing installation of the parts should be higher than the general requirements of dimensional accuracy, form and position accuracy, especially the alignment of hole or shaft neck and shoulder vertical degree, and to think about these problems, also must pay attention to the high speed and high temperature factors in the operation of the bearing. Shaft bearing system requires both high rigidity, asked for a light quality as much as possible, in order to overcome the contradiction, can take measures such as reducing the surface roughness and improve the surface strengthening in order to improve the bearing stiffness, using hollow shaft to reduce the system quality, etc. ( 1) Before the NTN bearing installation, should use the appropriate measuring tools according to the provisions of the technical requirements on the design drawing check the shaft and hole and machining quality of parts ( Such as dimensional accuracy and shape accuracy and surface roughness, etc. ) 。 ( 2) Shaft and the bearing hole assembly there such as bruising, burr, rust stain on the surface or solid particles ( Such as abrasive dust, sand, clay) Such as existence, not only can make the NTN import bearings in installation and the installation location is not correct, and solid particles such as falling into NTN bearing inner grinding effect, when NTN bearing rotating grinding or bruising NTN bearing surface of the work, so must be carefully checked before the installation, if found to have the above defects, should be revised. For example using oil file to remove burrs, bump touch mark, rusty spot, with fine abrasive cloth lighting, and like a clean solid particles, dirt, etc. ( 3) Should be assembled with clean the surface of the gasoline, kerosene, toluene and xylene solution washing clean, with dry clean duster cloth, and then coated with a thin layer of lubricating oil, it can make the operation more convenient installation. ( 4) When installed in the open the NTN bearing assembly, put it into the liquids such as gasoline with handle gently gently turning, to ensure the cage, encapsulated oil on the surface of the rolling element and raceway thoroughly washed clean. ( 5) When cleaning a lot of NTN bearing, with the first temperature is 90 ~ 100 ℃ heat oil pour hot to melt encapsulated oil, at the same time with seamless all mouth and no net exfoliation tools to dig the old oil, then pour hot a few minutes, then rinse with kerosene oil, clean with gasoline again finally. After washing clean, the NTN bearing on film gloves should be worn in the worktable of dry clean cloth or paper. ( 6) Note with NTN bearing seal do not clean with this law, the seal of the internal cleaning should remain the same.