The form and characteristics of the engine crankshaft

There are three types of engine crankshafts: integrally forged, integrally cast, and combined.

(1) The integrally forged crankshaft is characterized by compact structure, light weight, and high strength. However, it is difficult to obtain the required complex form, and it is not easy to integrate the balance weight with the crankshaft.

(2) The characteristics of integrally cast crankshaft are good workability, less metal cutting, low cost, and easy to obtain a reasonable structural shape. Such as oval crank arms, barrel shaped hollow journals, and unloading slots. In addition, it has a uniform stress distribution, but is prone to casting defects (especially at the corners of the crankshaft), which will seriously affect the fatigue strength of the crankshaft.

(3) Combined crankshafts: Due to the limited manufacturing capacity of the overall blank and the uneconomical replacement of the entire crankshaft in the event of partial damage, large crankshafts often use combined crankshafts. Composite crankshafts are generally divided into two types: nested crankshafts (full or half nested) and disk type composite crankshafts.