Is it normal to have clearance between the upper and lower parts of the crankshaft?
1 Answers
If the clearance is reasonable, it is normal. Otherwise, the high temperature during operation may cause the crankshaft to expand and seize. However, excessive clearance is not acceptable as it will generate significant noise. Introduction to Crankshaft: The crankshaft is the most critical component in an engine. It receives the force transmitted by the connecting rod and converts it into torque, which is then output through the crankshaft to drive other engine accessories. The crankshaft is subjected to the combined effects of centrifugal force from rotating masses, periodically varying gas inertia forces, and reciprocating inertia forces, resulting in bending and torsional loads. Therefore, the crankshaft must have sufficient strength and stiffness, with wear-resistant journal surfaces, uniform operation, and good balance. Crankshaft Structure: To reduce the mass of the crankshaft and the centrifugal force generated during operation, the crankshaft journals are often hollow. Oil holes are drilled on each journal surface to allow the introduction or discharge of oil for lubricating the journal surfaces. To minimize stress concentration, transition arcs are used at the connections between the main journals, crankpins, and crank arms.
