Some Causes of Crankshaft Bending and Breaking
2022-04-02
The cracks on the surface of the crankshaft journal and the bending and twisting of the crankshaft are the causes of the crankshaft fracture.
In addition, there are several reasons:
①The material of the crankshaft is not good, the manufacturing is defective, the heat treatment quality cannot be guaranteed, and the machining roughness cannot meet the design requirements.
② The flywheel is unbalanced, and the flywheel and the crankshaft are not coaxial, which will destroy the balance between the flywheel and the crankshaft, and cause the crankshaft to generate a large inertial force, resulting in fatigue fracture of the crankshaft.
③The weight difference of the replaced piston connecting rod group exceeds the limit, so that the explosive force and inertia force of each cylinder are inconsistent, and the force of each journal of the crankshaft is unbalanced, causing the crankshaft to break.
④ During installation, insufficient tightening torque of the flywheel bolts or nuts will cause the connection between the flywheel and the crankshaft to become loose, make the flywheel run out of balance, and generate a large inertial force, causing the crankshaft to break.
⑤ Bearings and journals are seriously worn, the matching clearance is too large, and the crankshaft is subjected to impact loads when the rotational speed changes abruptly.
⑥ Long-term use of the crankshaft, when grinding and repairing for more than three times, due to the corresponding reduction in the size of the journal, it is also easy to break the crankshaft.
⑦ The oil supply time is too early, causing the diesel engine to work rough; the throttle control is not good during work, and the speed of the diesel engine is unstable, which makes the crankshaft easy to break due to a large impact load.
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