Thrust-bearings designs

Figure 60.10 labels the parts of the Conrad anti-friction ball bearing. This design is widely used and is versatile because the deep-grooved raceways permit the rotating balls to rapidly adjust to radial and thrust loadings, or a combination of these loadings. 

A special 381 mm (15 inch) diameter tilting pad thrust bearing was designed and manufactured for these tests. It is shown in Figures 6 and 7. 

Thrust-Bearing Power Loss The power consumed by various thrust bearing types is an important consideration in any system. Power losses must be accurately predicted so that turbine efficiency can be computed and the oil supply system properly designed. 

A paper mill was using an ANSI end suction process pump with clear water service. The motor was designed properly. The pump axial thrust bearing ran hot, failing after three months of operation. It was replaced with an identical bearing. This ran during three months and also failed. All pump components were investigated and found that they complied with the specifications. These facts eliminated the defects of materials as a cause. 

The maximum outer diameter of thrust bearing (based on thrust collar design and allowable stresses)... 

When designing a system for thrust bearing proteetion, it is neeessary to monitor small ehanges in rotor axial movement equal to oil film thiekness. Probe system aeeuraey and probe mounting must be earefully analyzed to minimize temperature drift. Drift from temperature ehanges ean be unae-eeptably high. 

Herbage, B.S., High Speed Journal and Thrust Bearing Design, Proceedings of the 1st. Turbomachinery Symposium, Texas A M University, October 1972, pp. 56-61. 

A thrust-bearing failure is one of the worst things that ean happen to a maehine, sinee it often wreeks the maehine, sometimes eompletely. To evaluate the reliability of a thrust-bearing arrangement, we must first eonsider how a failure is initiated and evaluate the merits of the various designs. 

Compressors built to the API standard are required to have equal thrust capability in both directions that is, the bearing is to be symmetrically constructed. However, the thrust bearings can be combined using various numbers of pads on each side, or a tapered land can be combined with the multiple-segment design. Other combinations of the four thrust bear ings discussed are found in certain isolated applications. 

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