Causes of Fracture of Connecting Rod Bolts of Diesel Engine
Diesel engine connecting rod bolts are disposable and are not allowed to be reused. If the use of connecting rod bolts, due to the larger force, the bolt elongated, can easily lead to the bearing due to lack of bolts and the occurrence of rolling tile burning tile accident; at the same time due to lack of tightening force, bearing and crankshaft journal with the gap Increase, resulting in low oil pressure, resulting in excessive wear and tear of the bearing pad burns accident. Diesel engine system of high-strength diesel engine, connecting rod by the impact load larger, much larger than ordinary diesel engine, connecting rod bolts can easily lead to the use of broken, damage the engine cylinder block, causing the engine scrapped. Some units, although the replacement of the connecting rod bolts, there have been broken faults, there are individual engines in the running rod bolts suddenly broken.
Reason for failure:
① When the assembly torque is too tight, the force is not uniform. As the assembly is not strictly equipped with torque wrench, the specific tightening torque and do not understand, that the more tight the better; tighten the connecting rod bolts with a longer afterburner, tightening torque is too large, more than the bolt material Yield limit, so that the connecting rod bolts appear yield deformation, so that under the action of the impact load due to excessive elongation and fracture. Should be emphasized that must be tightened by standard rod bolts, do not think that the more tight, the greater the better strength.
② diesel engine connecting rod points a variety of levels, in the maintenance should be noted that can not use different levels of connecting rod. If the maintenance is due to sloppy will not carefully mess up the bar, wrong, will cause the joint head with the surface of the tie is not close, in the engine operation will cause the connecting rod loose and lead to break the bolt. WD615 series diesel engine connecting rod head for the oblique incision type, oblique angle was 45 °, connecting rod and connecting rod head with 60 ° zigzag positioning structure, this structure has a close fit, accurate positioning, reliable, compact specialty. If the maintenance of the rod will be confused, wrong, will inevitably lead to joint jagged positioning is not good, easily lead to the engine in the work of the rod cover loose, which led to the breakage of the connecting rod bolts.
③ diesel engine running in the flight failure or piston piston failure in the cylinder, the connecting rod bolts off. If the engine in the use of the flight failure occurred in the use of the engine should do a comprehensive inspection, it is best to replace the connecting rod bolts; if the operation of individual cylinders appeared more serious cylinder, in the replacement of the cylinder piston components should also link Bolt replacement.
④ material problems, processing defects and heat treatment process problems will also lead to connecting rod bolts in the engine running in the fracture.
① each time running 12000km for secondary maintenance, should be disassembled engine oil pan, check the use of engine bearings, if the individual pad gap is too large, should be replaced, the replacement should also replace the connecting rod bolts. Usually run if you find the engine is running smoothly, abnormal sound, it should be timely parking check.
② each time the maintenance of the new replacement of the connecting rod bolts should be checked, should pay attention to the bolt head, guide part of the threaded parts of the cracks or dent, thread tooth shape, pitch is abnormal, abnormal circumstances should be determined not to use.
③ When assembling the connecting rod cover, apply torque wrench, tighten according to the standard, prevent the torque is too large, too small.
④ selection of supporting the production of connecting rod bolts.