Super practical 】
Reason for crankshaft fracture 10 caterpillar excavator and the elimination method
Super practical 】
Reason for crankshaft fracture 10 excavators and elimination method & gt;>>
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Caterpillar crankshaft fracture usually from the start with the smallest crack, crack fracture site is mostly occur in the cylinder head or cylinder at the end of the connecting rod journal fillet in connection with the crank arm.
In the process of operation, the crack expanding gradually, to a certain degree of snap.
Observation often found on the surface of the broken part brown, this is obviously old crack, gloss shine group is the development trace of eventually snap.
Small make up today to take a look at what is the cause of the crank shaft broken! ! ! !
A small, rounded corners at the ends of the crankshaft journal when grinding crankshaft grinder for failing to properly control the axis of the crankshaft strength with rounded corners, rough machining, in addition to surface radius is too small, so the crankshaft fillet at work place produce larger stress concentration, and shorten the fatigue life of the crankshaft.
Second, the crankshaft main journal axis offset crankshaft main journal axis deviation, destroyed the dynamic balance of crankshaft components, powerful inertia force occurs at high speed diesel engines, lead to fracture.
Too much cold battle of three, crankshaft crankshaft after use for a long time, especially after tile burning or dao cylinder accident, will occur large bending, a correction shall be unloaded for cold press.
Crankshaft internal metal plastic deformation due to calibration will produce a lot of additional stress, thus reducing the strength of the crankshaft, if too much cold battle, is likely to be damaged or crankshaft appear crack, the crankshaft installed to use will soon break four, flywheel if loose flywheel bolt looseness, components of the crankshaft and lost the original dynamic equilibrium, diesel engine jitter occurs after operation, produce very big at the same time, the inertia force of the crankshaft fatigue, easy to fracture in the end.
Five, the crankshaft crankshaft shall not covet is cheap, poor quality of their own to buy must from normal channel replenish onr's stock.
Before installed should also carefully check, if there is a problem, timely replacement or return.
In addition, the engine overhaul, the crankshaft should be magnaflux inspection or oiled tap on a check, if there is radial shaft neck surface or extended to shoulder fillet of axial crack, the crankshaft is not used again.
Six, spindle watts no coaxial crankshaft assembly, if the cylinder body on each crankshaft centerline of coaxial, carter diesel engine work is likely to happen after the tile burning accident, holding shaft and crank shaft in strong under the action of alternating stress fracture.
Seven crankshaft assembly clearance is too large, if the crankshaft journal and bearing fit clearance is too large, the diesel engine crankshaft will impact bearing shell after operation, just alloy fall off and tile burning holding shaft, crankshaft is easy to damage.
Eight, the fuel supply time early or if uneven each cylinder oil injection pump fuel supply time early, check point on the piston has yet to burn to work and will cause the engine detonation, and made a hit from the alternating stress of the crankshaft.
If each cylinder oil, for each cylinder outbreak cases of inconsistent and make the crankshaft journal bearing not divide evenly, thus fatigue, cracks prematurely.
Nine, crankshaft worn if poor lubrication oil pump, oil dirt, poor circulation, will make a lack of oil, oil pressure, cause between crankshaft and bearing bush could not form normal lubricating oil film, resulting in a dry friction and cause broken tile burning shaft, crankshaft and so on big accident.
Ten, if improper operation caused by fracture in the gas is too big or too small, frequent braking or over load operation of a long period of time, will be too much to the crankshaft torque or impact load.
In addition, the diesel engine coasters, dao cylinder and valve and so on accident, is easy to fracture.