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S is the Sommerfeld Number or bearing characteristic number r is the shaft radius c is the radial clearance μ is the absolute viscosity of the lubricant N is the speed of the rotating shaft in rev/s P is the load per unit of projected bearing area. The second part of the equation is seen to be the Hersey number.
Hersey's original formula uses the rotational speed (revolutions per unit time) for N and the load per projected area (i.e. the product of a journal bearing's length and diameter) for P. Alternatively, the Hersey number is the dimensionless number obtained from the velocity (m/s) times the dynamic viscosity (Pa∙s = N∙s/m2), divided by the ...
Spiral groove thrust bearings produce the required pressure to keep the bearing surfaces lubricated and separated purely by the pumping effect of the grooves, whereas journal, conical and spherical forms also get extra pressure generation by the hydrodynamic bearing wedge action. When the parts of the bearings are rotated with respect to each ...
If an integral bearing wears out, the item may be replaced or reworked to accept a bushing. Integral bearings were very common in 19th-century machinery, but became progressively less common as interchangeable manufacture became popular. For example, a common integral plain bearing is the hinge, which is both a thrust bearing and a journal bearing.
A jewel bearing is a plain bearing in which a metal spindle turns in a jewel-lined pivot hole. The hole is typically shaped like a torus and is slightly larger than the shaft diameter. The jewels are typically made from the mineral corundum , usually either synthetic sapphire or synthetic ruby .
An axlebox, also known as a journal box in North America, is the mechanical subassembly on each end of the axles under a railway wagon, coach or locomotive; it contains bearings and thus transfers the wagon, coach or locomotive weight to the wheels and rails; the bearing design is typically oil-bathed plain bearings on older rolling stock, or roller bearings on newer rolling stock.
p = bearing pressure(N/MM2) For any given bearing, there is a value for indicated by C, for which the coefficient of friction is at a minimum. The bearing should not be operated at this value of bearing modulus, since a slight decrease in speed or a slight increase in pressure will make the part of a shaft or axle that rests on bearings operate ...
A spherical bearing is a bearing that permits rotation about a central point in two orthogonal directions (usually within a specified angular limit based on the bearing geometry). Typically these bearings support a rotating shaft in the bore of the inner ring that must move not only rotationally, but also at an angle.