The precision of the rolling mill bearing is introduced

The precision of the rolling mill bearing 2020 - 12 - Source: 19 dmdbearing bearing precision points ( The main) Dimensional accuracy and rotation accuracy. Precision grade has been standardized, divided into P0, P6, P5, P4, P2 grade five levels. Since a level 0, in turn, improve accuracy, for general mill level 0 is enough, but in the non-ferrous metal industry and high-end cold-rolled, level 5 or higher precision. Although more accuracy grade is set by the ISO standards as a benchmark, but its name is different in the national standard. Commonly used on the rolling mill bearing commonly DIN standard code to call 1 dimensional accuracy ( Associated with the axis and shell installation project) 1, inner diameter, outer diameter, width and assembly width within the allowable deviation of 2, the roller group months-moons last contact outside diameter and the diameter of the allowable deviation 3, acceptable limit value of the chamfer size 4, 5 width to allow changes, both inside and outside surface, rolling body, face and acceptable limit value of the channel roughness. 2 rotating accuracy ( Projects related to the rotator to beat) 1, inner ring and outer ring radial runout and axial runout 2, without the permission of the inner ring allows transverse beating 3 plane inclination to allow change quantity, diameter 4 and the change of the thickness of the thrust bearing raceway allowed quantity 5, to allow the taper hole deviation and allowed to change the centripetal bearing ( Except for circular cone roller bearings) , tapered roller bearing, thrust bearing of the dimensional tolerance standard each are not identical, specific can refer to the national standard GB/T30794. Bearing the cooperation and tolerance of valuable place valuable content is: 1, the principle of bearing fit ( 1) Bearing circumferential direction must support is good, can give full play to the bearing capacity of the bearing. Therefore, should be used inside and outside the circle is tight. Ring is a thin wall parts, fit clearance is big, the ring will occur bending deformation after loading, influence the internal load and stress distribution, to produce stress concentration, also affecting the precision of the spinning deformation of the ring. ( 2) Ring by rotating load can't slide along the circumferential direction of the mating surfaces. But should be ring may be produced by fixed load small turning, slowly change loading area. （ 3) Non separation bearing of winding end bearing should be allowed a ring ( Is generally coat) Relative matching surface to axial movement, the ring should be loose some. （ 4) Because of the interference fit the quantity is not too large, lead to bearing clearance negative even roll body were jammed. （ 5) The precision of matching parts must conform to the requirements. Bearing ring is a thin wall parts, shaft neck or hole switch error will be passed to the rolling road, is equal to the reduced the accuracy of bearing. （ 6) Bearing installation and disassembly is convenient. There is the roll bearing ring with the rotation of the heavy load, but because of the frequent or choose loose installation. 2, with the bearing and the shaft and the shell hole bearing with the shaft with the use of hole system, with the bearing and the shell hole adopts the basic shaft system. Bearings and shaft and machine manufacturing tolerance matching system, adopted by the bearing inside diameter tolerance of minus tolerance. Therefore, under the condition of the same fit, the bearing inner diameter of the mixing ratio is usually cooperate more closely. Tolerance of bearing outside diameter has negative tolerance, but the tolerances and general tolerance system is not the same.