Technology Study Of Some Difficult Issues Of The Connecting Rod And Crankcase Of 6170 Diesel Engine During Machining Process

The machining process and assembly quality of the connecting rod big end bearing hole and the engine body main bearing hole, has a very important effect on the performance, noise, reliability and use life of the diesel engine. Assembly quality of these two holes is restricted by the machining process quality. Moreover, these holes are emphases of technology design and working procedure control. Holes of dividing in the middle structure, when assembling with bearings(tiles), often come forth with deformation. Because of the simple equipment of 6170 diesel engines, cases of holes deformation are more occurred.This thesis introduced briefly the processing technology of connecting rod big end bearing hole and engine body main bearing hole of 6170 diesel engine, analyzed the reason and harm of deformation of these two holes. One of the reasons of the deformation of the connecting rod big end—process quality of the saw-teeth used for the orientation of connecting rod and connecting cover, is chosen as study emphasis in this text. Assembled processing technique of "mill the connecting face with column roll milling cutter + mill the position saw-teeth with figuration milling cutter + mill the unwanted teeth with plate milling cutter", is applied in the processing of the position gear.This thesis discussed questions of screw down torque of the connecting rod screw, effect of deformation of the main bearing bolt torque to the connecting rod big end bearing hole and the engine body main bearing hole. After calculation and examination compare, we can come to conclusion that torque coherence of hole process and bearing assembly will bring big effect on bearing hole deformation.Furthermore, according to calculation and examination data, reasonable torque of spare parts process is established, which can eliminate the deformation effect on the above two holes from the screw down torque.