Cold extrusion process difference of INA angular contact ball bearings

Cold extrusion is a forming process that uses plastic deformation of a metal material to obtain a part of the desired shape, size, and mechanical properties, so the blank volume is equal to the part volume.

The determination of the diameter of the blank is critical. It determines the degree of deformation of the positively extruded part. A reasonable diameter size ensures the balance of the degree of deformation of the two extrusions, so as to reduce the deformation resistance during extrusion and avoid the extrusion of the imported bearing parts. Defects extend the life of the mold. According to the experience of extruded bearing steel, the compression ratio of the positive extrusion section of the complex opening part is preferably controlled within 50%.
First, the cold extrusion process according to the angular contact ball bearing parts shape and dimensional accuracy, the use of blanks to prepare a higher quality lathe blanking method, the billet after annealing softening, rolling, pickling, and then phosphating, saponification, Finally squeeze.

Second, in the strength theory and design calculation of the cold extrusion die, the die is generally regarded as a thick-walled cylinder subjected to uniform pressure. For thick-walled cylinders whose INA bearings are subjected to internal working pressure, excessive tangential stress at the inner diameter is the main cause of cracking and damage of the mold. Therefore, when calculating and verifying the strength, each inner surface should be checked. The resultant stress is such that it does not exceed the tensile yield limit of the material.

Third, the maximum shear stress strength theory believes that the cause of material damage is the maximum shear stress, as long as the maximum shear stress reaches a certain value (ie, the maximum shear stress that is destroyed during simple tensile compression), the material will be destroyed.

Reduce the vibration of the rolling surface grinding superfine, obtain good surface processing shape accuracy and surface texture quality to reduce vibration, the grinding super machine tool must have good vibration resistance, the important structural parts such as the bed body have vibration absorption, super precision machine tool The oilstone oscillating system has good anti-vibration performance; the grinding speed is improved. The foreign grinding 6202 outer raceway generally adopts 60,000 electric spindles, and the grinding speed is above 60m/s. It is generally much lower in China, mainly by the main shaft and main bearing. Performance limitations. In high-speed grinding, the grinding force is small, the grinding deterioration layer is thin, it is not easy to burn, and the machining precision and efficiency can be improved, which has great influence on the low-noise angular contact ball bearing; the dynamic and static stiffness of the main shaft and its speed characteristics are low noise. INA bearing grinding vibration has great influence, the higher the rigidity, the less sensitive the grinding speed is to the change of grinding force, the smaller the vibration of the grinding system; the higher the rigidity of the spindle bearing, the random dynamic balance technology is used to improve the grinding spindle Vibration resistance. The vibration speed of foreign grinding heads (such as Gamfior) is about one-tenth of that of domestic general spindles; it is important to improve the cutting performance and dressing quality of grinding wheel. The main problem of the current grinding wheel in China is that the uniformity of the structure is poor, which seriously affects the super-processing quality of the low-noise angular contact ball bearing; sufficient cooling to improve the filtration accuracy; improve the feed resolution of the precision feeding system, reduce the feed inertia; reasonable grinding The super-processing parameters and processing flow are factors that cannot be ignored. The grinding allowance is small, the geometrical tolerance is strict, the outer diameter of the small and medium-sized ball bearings should not be super-finished, and the coarse grinding should not be separated to ensure a good surface. quality.

The mounting method of the INA bearing varies depending on the bearing structure, fit, and conditions. Generally, since the shaft is mostly rotated, the inner ring needs an interference fit. Cylindrical bore bearings, press with a press, or use a hot charging method. For taper holes, mount directly on the taper shaft or with a sleeve.

When installed in the outer casing, there is usually a lot of clearance and the outer ring has an interference. It is usually pressed by a press or there is a cold shrink fit method after cooling. When dry ice is used as the coolant and the shrinkage is installed, the moisture in the air will condense on the surface of the angular contact bearing. Therefore, appropriate rust prevention measures are required.