https://www.xyexcavator.com/excavator/wheel-excavator/b75s-new-wheel-excavator.htmlThe fracture of crankshaft usually starts from the smallest crack, and most of the fracture parts are at the connecting part between the head cylinder or the end cylinder connecting rod journal fillet and the crank arm. In the process of operation, the crack expands gradually and breaks suddenly when it reaches a certain degree. The brown part is often found on the fracture surface, which is obviously an old crack. If the broken surface is shiny, it means that it is suddenly broken. This article will summarize the four causes of excavator crankshaft fracture besides the causes mentioned in the previous article.
1. loose flywheel
If the flywheel bolts are loose, the crankshaft assembly will lose its original dynamic balance, and the diesel engine will vibrate after operation, which will produce a large inertia force, resulting in crankshaft fatigue and easy fracture at the tail end.
2. poor quality of crankshaft
Crankshaft must be purchased from regular channels. Check carefully before installation. If there is any problem, replace or return it in time. In addition, during engine maintenance, the crankshaft shall be subject to magnetic flaw detection or oil immersion percussion inspection. If there are radial or axial cracks extending to the fillet of the shoulder on the surface of the journal, the crankshaft can not be reused.
3. different shafts of main bearing bush
When the crankshaft is assembled, if the center lines of each main bearing on the cylinder block are different, the diesel engine is prone to serious engine wear after operation. The crankshaft will also break under the strong action of alternating stress.
4. the crankshaft assembly clearance is too large
If the fit clearance between crankshaft journal and bearing bush is too large, the crankshaft will impact the bearing bush after the diesel engine runs. Only the alloy falls off and causes engine wear, and the crankshaft is easy to be damaged.
