Antifriction bearing

Fig. 9. Cutaway view of a briquettiag—compactiag machine. A, predensifying feeder B, feeder screw C, machine housing D, antifriction bearing E, machined bearing block F, base frame G, pocketed or cormgated roUs H, hydrauHc system I, speed reducer J, gears K, hydrauHc accumulator and L,...

The axial flow compressors in aero gas turbines are heavily loaded. The aspecl ratio of the blades, especially the first few stages, can be as high as 4.0, and the effecl of streamhne curvature is substantial. The streamline configuration is a function of the annular passage area, the camber and thickness distribution of the blade, and the flow angles at the inlet and outlet of the blades. The shafts on these units are supported on antifriction bearings (roller or ball bearings). 

Figure 12-61 also illustrates three basic types of trunnion rollbearing assemblies. Antifriction pihow blocks are the most common on modern diyers however, when the dryer load requires larger than a 12.7- to 15.2-cm-diameter bearing on the trunnion shaft, the dead-shaft antifriction bearing is substituted. This represents a considerable cost saving compared with the larger pillow blocks. They are completely sealed and continuously bathed in lubricant. Pillow-block bushings are less often used. The thrust washers are difficult to seal against dust, and they draw more power. Thrust roll mountings are depicted also in Fig. 12-61. These are usually dead-shaft.

Radial Bearings Antifriction bearings are largely unsuitable for these applications, chiefly because of the special attention and maintenance which they demand. 

Three types of bearings will be discussed oil-film bearings, rolling-element bearings (also known as antifriction bearings), and magnetic bearings. 

Ball/race frequencies in antifriction bearings usually used in aero-... 

Antifriction bearings play an important part in the safe performance of the tool. The most likely requirements for bearing placement are very loose or bent cages (retainers), corrosion, abrasion, inadequate (or improper) lubrication, and spalling from fatigue. Excessive clearance may indicate improper adjustment or assembly and should be corrected. Repair of antifriction bearings should not be attempted by field or shop personnel. Consultation with the equipment manufacturer is recommended in case of unexplained or repeated bearing failure. 

The inside diameter of socket and swivel-socket baskets should be in. larger than the nominal diameter of the wire rope inserted. Alloy or carbon steel, heat treated, will best serve for sheave grooves. Antifriction bearings are recommended for all rotating sheaves. 

Herbeck and Strohecker used machines designed particularly for comparing the merits of lubricants in preventing fretting corrosion of antifriction bearings. One provided for both oscillating conditions and combination radial and thrust loads to simulate service. Another was concerned primarily with thrust bearings and correlated satisfactorily with the radial load tester. 

Chromium Compression rings, antifriction bearings, shafts... 

Iron Cylinders, liners, pistons, rings, valves, valve guides, gears, shafts, clutch plates, antifriction bearings, rust... 

Nickel Valves, valve guides, antifriction bearings... 

More recent developments in this country have included synthesis of relatively stable oils of low volatility, low pour point, and high viscosity index by esterification of octyl alcohols, such as 2-ethylhexanol, with dibasic acids such as adipic acid and sebacic acid (3). Octyl alcohols may be synthesized from petroleum hydrocarbons via the oxo process. Although of relatively high cost, these synthetic oils find general application in making greases for lubrication of antifriction bearings and instruments in aircraft. 

The unusual properties of silicones make them useful for some special applications as lubricants (20). They are relatively resistant to deterioration by heat or oxidation, and have the desirable properties of high viscosity index, low pour point, and low volatility. They may promote wear in steel-to-steel bearing surfaces under conditions of sliding friction, and are not generally useful for such applications. Silicones are satisfactory lubricants in antifriction bearings and in some bearing combinations other than steel sliding on steel. 

Greases made with lithium stearate and synthetic oils, such as 2-ethylhexyl sebacate or adipate, are especially applicable to lubrication of bearings that are subjected to both high and low temperatures. An important application is lubrication of antifriction bearings and instruments in aircraft which may encounter temperatures as low as —100° F. at high altitudes. 

The most common test is a minting beam type in which a carefully machined and polished sample is loaded as a beam while rotating in antifriction bearings. As any poitti in the periphery rotates from top to bortom to top position the stress changes Irani maximum compression to maximum tension and back to maximum compression From 4 to 8 or more individual tests at various maximum stress levels may he required to detemiine the endurance limit. 

Devine, M.J., Lamson, E.R. and Bowen, J.H., Antifriction Bearing Design Considerations for Solid Lubrication, ASME Preprint 63-MD-43, (1963). 

Risdon, T.J. and Binkelman, J.P., Oxidation Stability and Antifriction Bearing Performance of Lubricants Containing Molybdenum Disulfide, NLGI Spokesman, 32, 115, (1968). 

Figure 101 is the photograph of a typical drum granulator for fertilizers. The shell (1) is fitted with steel tires (2) and the drum rests on forged steel trunnions (3) with antifriction bearings which are mounted on a heavy structural... 

Design. Two antifriction bearing assemblies shall be provided, one assembly fi-ee to float witiiin die frame to cany radial loading only, and the other assembly arranged to carry bodi radial loading and axial dirust... 

VulkoIIan . [Bayer Miles] Water-crosslinked polyurethane elastomer for pun diaphragms, coupling elements, solid dres, rollers, pump housings, seals, wipers, bush and split sections ftK antifriction bearings and flexible couplings. 

As in all medium-pressure agglomerators that use rollers for the densification and extrusion of moist and/or plastic materials, the primary cause for roller rotation is friction between the roller surface and the material to be processed. The roller is mounted on a shaft with sealed antifriction bearings and is brought to close proximity... 

Support AFB Antifriction bearings (B = ball R = roll N = needle)... 

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