Power End Components

Large roller bearings (typically cylindrical or tapered roller) that support the crankshaft in the crankcase and carry the primary radial loads transmitted from the connecting rods. They set crankshaft alignment and absorb the cyclic loading of each pumping stroke.

The big-end bearings that ride on the crankshaft's eccentric crankpin journals, including precision roller bearings or split babbitt/journal inserts. They link the rotating crankshaft to the reciprocating crosshead through the connecting rod.

The sliding crosshead, crosshead bushing, and wrist (gudgeon) pin that convert the angular motion of the connecting rod into pure linear motion aligned with the plunger. The crosshead bushing provides the wear surface that guides the crosshead within its bore.

Needle roller bearings and bushings at the crosshead/connecting-rod pin joint that handle high oscillating loads in a compact radial envelope. Their small cross-section suits the tight space at the small end of the connecting rod.

Bearings supporting the pinion (input) shaft and bull gear that reduce prime-mover speed to crankshaft speed. These are typically tapered or cylindrical roller bearings sized for combined gear separating and tangential loads.

Plain sliding bearings using a soft babbitt (tin- or lead-based) lining on a steel backing, applied where conformable, hydrodynamic load support is preferred over rolling elements. They tolerate momentary boundary lubrication and embed contaminants.

Deep groove ball bearings carry combined radial and light axial loads on auxiliary shafts, while angular contact ball bearings handle higher unidirectional thrust such as gear or shaft end-location duties. Both are used in supporting positions within the power end and its drive train.

The forged crankshaft with its eccentric crankpin throws, plus associated eccentric bearings, that establish the pump stroke length and drive the connecting rods. Stroke geometry is fixed by the crankpin offset machined into the shaft.