Failure Reason, Repair Method and Preventive Measures for Crankshaft Axes of B Type Injection Pump

At present, most of the major engineering equipment, such as TY120 bulldozers, ZL series loaders, PY160 road graders and 75KW mobile power plants equipped by our army's Corps of Engineers (sub-teams), most adopt the 6135 diesel engine as the mechanical power source device . As the "heart" type B 6136 diesel injection pump, camshafts often break during equipment training and camping driving, which seriously affected the successful completion of military training and exercise tasks. Combined with teaching and repairing equipment practice, this paper introduces the failure reason, repair method and preventive measures of camshaft fracture of 6135 diesel engine type B injection pump. 1 Fault reason 6135 type diesel engine used in the B-type pump plunger pump, which is fixed to the bracket on one side of the diesel engine body by four bolts from the diesel engine crankshaft driven by the timing gear, the fuel injection camshaft and the pump Drive shaft coupling. The lift of the injection pump cam is 10mm, the center distance of the minute pump is 40mm, and the maximum speed of the pump reaches 1000rpm. Due to the high rotational speed of the fuel injection pump and the four-point support, the installation form and improper use of the pump cause abrasion of the arc surface of the pump body at the joint of the fuel injection pump and the support (the abrasion of the arc surface in the support is relatively small) Down, so that the axis of the camshaft and pump drive shaft offset. Injection pump camshaft by the twisting, bending and swinging and other forces generated additional alternating stress, eventually leading to fatigue fracture camshaft. 2 Repair 6135 type diesel engine type B Injection pump camshaft journal surface finish of not less than 8, the hardness of not less than HRC45, cylindricity tolerance of 0.10mm, full length straightness tolerance of 0.05mm, are precision parts.For the repair of camshaft fracture, the general use of "change Piece repair method ", that is, replace the camshaft.But if the replacement after repair if not ruled out the root causes of camshaft rupture, will inevitably lead to camshaft rupture again.In order to avoid repeated camshaft fracture, usually replace the B-type pump body or pump B-type injection pump assembly.This approach is neither economical nor difficult to guarantee (using the B-type pump body pump injection pump test bench required pump) Especially in the field of conditions more difficult to protect.After many years of practice, the following three kinds of emergency methods are more suitable for field conditions on the 6135 diesel engine B-type fuel injection camshaft repair fracture .2.1 original repair camshaft rupture The root cause is the pump pump wear. Based on this, we can welding the pump body, brazing to take the "heap fill" method of welding, the thickness of the heap compensation and slightly larger than the wear area. And grinding method will be polished polished polished flat, restore the original geometry of the pump body, cleaning the various parts, installed after commissioning can be used. Original repair method can also be used metal rubber make up the method to repair the pump body pump . That is, with a good modulation of the metal coating in the wear area, the thickness and area of ​​the metal coating is slightly greater than the amount of wear and tear, to be solidified metal gel 20 to 30 minutes after the metal coated with a metal polishing areas, cleaning parts , After installation debugging can be used. 2.2 parts disassemble method 6135 Diesel Engine B-type fuel pump pump body material is generally cast iron or aluminum, although the material is different , The installation of the same size and internal structure.Therefore, can be scrapped 6135 diesel engine type B injection pump, according to the need to disassemble available pump body, camshaft and other parts, assembled into a complete type B injection pump , After debugging qualified installed use. 2.3 additional parts method in the field conditions, can not use the "original repair law" and "parts removed spelling method", you can use the "additional parts method." Specific methods are: Grinding abrasive cloth abrasive polishing machine parts (wear parts with the bracket with the surface, and by the end of the pump drive shaft is more serious); ② with a deep caliper after grinding worn parts of the depth, wear depth is generally 0.5 ~ 1mm; ③ with copper or iron pieces made into additional parts gasket. Additional parts thickness measured according to the size of the depth of the worn parts to determine the width of the additional parts is approximately equal to the thickness of the bracket, the additional parts of the length of approximately equal to Pump body wear parts of the arc length; ④ will be made of good gasket attached to the bracket and the wear parts of the pump body. The number of additional gaskets is determined according to the depth of the worn parts measured, generally not more than three; ⑤ start the test after installation and adjustment, delivery. 3 Precautions 6135 Diesel Engine B-type fuel pump pump body wear is mainly due to the relatively loose body and bracket caused. Therefore, we can prevent it from the following three aspects. 3.1 Installation should be correct Type 6135 Diesel Engine B-type fuel injection pump often due to uneven fuel supply for each cylinder, fuel supply interval angle is not allowed to remove the whole repair and so on, the overall installation after the school pump. Installation should pay attention to the following points: ① fixed bolt diagonal tight. If you first set tight on the outside or on the side of the body by two bolts, on the one hand may result in a good adjustment of the fuel supply advance was destroyed. The first fixed by the body side of the two fixed bolts, advance advance angle of oil supply; first fixed outside the two fixed bolts, fuel supply ahead of schedule in advance. On the other hand, the camshaft axis of the fuel injection pump and the axis of the drive shaft of the oil pump may have deviated during installation. After the engine is started, the camshaft is directly subjected to additional alternating stress and fatigue fracture. ② fixed bolts should be sub-2 to 3 times tight. ③ The tightening torque of the fixing bolt should be between 1.5 ~ 2.5kg (the fixing bolt is M8 × 1 or M10 × 1 fine thread, the tightening torque is too big and easy to damage the thread); ④ The fixing bolt should be tight in place . In practice, two fixing bolts close to one side of the body often appear, which are not tightly fixed due to the limitation of the installation position, but the two fixing bolts on the outside are tightly tightened. 3.2 Maintenance should be appropriate 6135 diesel engine B-type fuel injection pump diesel engine fuel supply system is an important component. In the use of maintenance process should pay attention to the following three points: ① oil pump oil quantity, quality to meet the requirements. Such as poor lubrication, ranging from the pump drive components early wear and tear, heavy bearing stuck, resulting in camshaft was broken. ② camshaft axial clearance should be appropriate. Camshaft axial clearance is generally about 0.03 ~ 0.15mm, the gap is too large, the camshaft wear and tear accelerated, the engine is not running smoothly, causing the pump early wear and tear. ③ fuel pump advance angle and the cylinder oil supply interval angle to meet the requirements. If the fuel supply advance angle and the interval between each cylinder oil supply do not meet the requirements, not only will the engine power, economic deterioration, but also cause the engine start difficult, unstable operation, leading to pump wear and tear accelerated. 3.3 Check to 6135 type diesel engine B-type fuel pump pump and bracket loose situation, usually during the week of maintenance inspection. If you find the engine has abnormal conditions or loose body, should be promptly checked tight. Check the tight method according to the installation requirements. These are the 6135 diesel engine B-type fuel injection camshaft failure of the cause of failure, repair methods and preventive measures introduced. Practice has proved that the above emergency methods and preventive measures are scientific, reasonable, feasible and practical, with high military and economic benefits. For my colleagues learn from.