Causes of Engine Crankshaft Fracture (Part 2)

May. 25, 2020

● the fatal factor of crack deformation

4, crankshaft journal surface crack

Most cases of crankshaft crack can be divided into two types. The first is the excessive fillet between the crank and the journal, which is harmful and easy to cause broken shaft damage to the engine. Another case occurs in the crankshaft oil hole cracks along the oil hole along with the axial development.

The defects of manufacture and repair and improper use are easy to make modern MITSUBISHI crankshafts crack: if you use, improper repair shaft neck surface roughness is poor, indentation, scratch, defects such as corrosion, pit, failure to promptly eliminate, fatigue crack production and the development will start from here.

In addition, the lack of lubrication, after the repair and grinding of the round corner version of the shaft shoulder after small not smooth or surface roughness, as well as surfacing welding repair journal, is easy to cause the generation of cracks.

Oem Alloy Steel Crankshafts For Cars

Oem Alloy Steel Crankshafts For Cars

5. Crankshaft deformation

The deformation of modern crankshaft is usually bending and torsional. The deformed crankshaft will lead to wear and tear, fatigue acceleration, crankshaft fracture, and excessive mechanical vibration.

Human and non-human reasons are likely to lead to crankshaft deformation, most of the former are caused by the driver's illegal operation or accidents, heavy load, engine work rough, take violent braking measures in Overspeed operation, poor lubrication and other human factors may lead to crankshaft deformation.

The non-human reason is that the crankshaft is deformed by periodic gas pressure, reciprocating inertia force, rotating centrifugal force, and mechanical braking force.

6. Broken crankshaft

Crankshaft fracture also represents the damage of the engine, its reasons are more complex, the common fracture site has the crankshaft neck two adjacent rounded corner junction crank arm, connecting rod journal through the oil hole, connecting rod journal root or spindle neck root, the installation of flywheel conical keyway and other parts. All causes of crankshaft journal surface crack and crankshaft bending and distortion are the causes of crankshaft fracture.

● timely maintenance to prevent damage

The above is our summary of the crankshaft is easy to damage the situation, after knowing the reason, in the daily repair and maintenance, to try to avoid this phenomenon, so as not to cause irreversible damage to the engine.

1. Timely maintenance to ensure the quality of lubricating oil; When repairing and assembling, make sure the fit-gap between the axle neck and the axle bush is correct; Avoid engine overload for a long time.

2. When repairing the engine, it is necessary to carefully check whether there is any crack in the stress concentrated part of the crankshaft. If possible, an instrument can be used for magnetic inspection.

3, when grinding the crankshaft should keep the transition of the journal and crank connection rounded Angle, must not be ground into sharp Angle, otherwise, it will produce greater stress concentration, resulting in the crankshaft broken.

4. Pay attention to the balance of crankshaft, flywheel, and clutch. When the clutch assembly is installed on the flywheel, shim should be arranged at the fixing bolt, and there should be no chattering to avoid deterioration of crankshaft working conditions.

5, regularly check the bearing and flywheel and other parts of the fixed bolt pre-tightening force. When installing the crankshaft and tightening the cover nut of the main bearing, it shall be tightened several times according to the specified torque and order.

● epilogue:

OEM Alloy steel crankshafts for cars is one of the most important parts of the engine. It takes the force from the connecting rod and converts it into a torque that passes through the crankshaft and drives other parts of the engine. For the internal parts of the engine, it can be said that all the glory, all the loss. Users in peacetime use must be diligent in maintenance, in order to ensure the engine powerfully.

In order to smooth and safe driving, the custom automobile spare parts factory suggests that you should do more checks at ordinary times, deal with fault signals in a timely manner, and try your best to nip hidden dangers in the bud. Always bear in mind that safety awareness is more important than hardware.