柴油发动机零件-机轴

The crankshaft is made of high strength alloy steel 42CrMo with four balance weights, one time formed by forging. It has soft nitride treatment after finish machining, so its strength and stiffness and wear-resisting are all good. The main bearing is steel back three elements alloy plated copper lead shell, which has big capacity of bearing, totally 10 pieces. No.3 main bearing shell (down) is different from others, no oil groove on the shell face, dont apply oil on the shell back when assemble the shell. The material of thrust washer is steel back high tin aluminum alloy installed on the fourth bearing and positioned by the lower thrust washer extended tail, keeping the working surface (the side with oil trough) towards crank-web. The main bearing caps and engine block are machined in pairs, there are numbers and serial numbers on the caps. Except positioned by lug, like other caps, the fourth bearing cap also has pin bush for position. The main bearing bolts are lubricated with diesel engine oil, the tighten torque is 216 235N·m (22 24 kgf·m), it should start to tight alternatively from the center (no.3 main bearing) towards both sides. After tight, the crankshaft can be rotated smoothly.