The connecting rod is a crucial component in an engine, connecting the piston and crankshaft. It converts the reciprocating motion of the piston into the rotational motion of the crankshaft and transmits gas pressure. Its structure includes components such as the connecting rod body, connecting rod cap, connecting rod bolts, and connecting rod bearings. The rod body often uses an I-shaped or H-shaped cross-section to balance strength and mass.
The connecting rod assembly must withstand cyclic alternating loads. The main forms of failure are fatigue fracture and excessive deformation, with fractures occurring primarily in three high-stress areas. Fatigue strength can be improved by optimizing the shape, fillet transitions, and surface finishing processes. V-type engines use connecting rod types including parallel, forked, and main/secondary connecting rods, with the big end using a separate design and secured by connecting rod bolts. The connecting rod bearings form a mating pair with the crankshaft connecting rod journals, commonly using anti-friction alloys such as white alloys and copper-lead alloys.
