Väntvõll

Väntvõll, or crankshaft, is a rotating shaft used in many internal combustion engines and similar machines. It converts the reciprocating motion of pistons into rotational motion that powers the engine and drives accessories such as the flywheel, generator, and oil pump.

Structure and function: The crankshaft typically consists of main journals that run in engine bearings, crankpins (connecting-rod journals) that connect to the connecting rods, and webs that link the journals. Many designs include counterweights to balance inertial forces. Fillets at transitions reduce stress concentrations, and oil passages provide lubrication to bearings and crankpins.

Variants and configurations: Crankshafts can be single-throw or multi-throw. Inline engines use a straight shaft with several throws, while V- and opposed-engine layouts arrange throws to balance forces differently. Cross-plane and flat-plane configurations influence primary and secondary balance and torsional vibrations, affecting engine feel and noise.

Manufacturing and materials: Common materials are alloy steel or cast iron. Manufacturing methods include forging or casting, followed by precision machining, grinding, and heat treatment. The crankshaft is balanced during production, with tolerances specified for runout and bearing clearance. Some designs integrate gear or pulley interfaces directly onto the shaft.

Operation, balance, and maintenance: The crankshaft is subjected to bending and torsional stresses from piston forces. Proper lubrication, timing, and alignment are essential to prevent bearing wear and fatigue. Wear-prone areas, such as fillets and bearing surfaces, are routinely inspected, and shafts may be equipped with vibration dampers to control torsional vibrations.

Applications: Primary use is in automotive and motorcycle engines, but crankshafts are also found in marine, stationary, and certain pump or compressor systems. High-performance variants aim to reduce weight and improve balance while maintaining strength.