tailieunhanh - Handbook of Lubrication Part 14

Tham khảo tài liệu 'handbook of lubrication part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Volume II 523 FIGURE 19. Inner ring shaft nomenclature. Symbols Pc constant pressure at interface Ô effeclive interference Ei modulus of elasticity inner membrane Eo modulus of elasticity outer membrane vi Poisson s ratio inner membrane vo Poisson s ratio outer membrane and Ad change in diameter. Any consistent system of units may be used. Housing or outer ring mountings encounter many of the same problems. Housings do perform some other functions such as providing a lubricant reservoir and providing seals to prevent the egress of lubricant and ingress of contaminants. Housings are often purchased from the bearing manufacturer may be either solid or split and are usually sized for a loose fit with the bearing OD. Where the load is stationary with respect to the inner ring and rotates with respect to the outer ring however the outer ring is usually mounted with an interference fit. An example would be a vibrating screen. Both shaft and housing mounting are susceptible to fretting. This physical chemical wear phenomenon results from relative motion of very small amplitude between surfaces. Fretting is especially troublesome in the slip fit mounting and determines the limiting load given It also occurs in other mounting types if the interface pressure at mounting surfaces is insufficient to support the shear stresses developed by application loads. For many types of angular contact bearings such as tapered roller bearings the mounting arrangement must provide for adjustment of clearance within the bearings. The change in diameter of a press fit ring can be estimated from the following equations see Figure 19 for definitions of terms Pc -w 14 Ei dJ-d Eo d -dp Ej Eo 15 Where both members are steel and di 0 . an inner ring on a solid shaft the above equations reduce to 16 Copyright 1983 CRC Press LLC 524 CRC Handbook of Lubrication Materials and Processing For cylindrical and needle roller bearings one or both rings are often omitted with the rollers running