Reciprocating compressor construction--crankshaft and connect rod

Crankcase body parts

The crank mechanism supported in the crankcase consists of a double crank and six connecting rods.

The sturdy crankcase is made of cast iron and its bottom serves as an oil pan. Another special oil storage tank, as a continuation of the oil pan, draws in the lubricating oil required by the crank mechanism from here. An oil distributor is installed on the side of the crankcase, and the oil from the oil distributor flows through the oil filter. The oil filler pipe is installed on the upper part of the crankcase.

The large cover plates on the front two sides are used to ensure that the crankcase with crank mechanism does not leak oil. The crankcase ventilation device balances the pressure inside and outside the crankcase. The cylinder is installed on the crankcase in two rows. Each row consists of three W-shaped cylinders. The angle between the two rows of cylinders is 60 °.

The crankshaft is forged from specially heat treatable steel and supported by two long-life roller bearings. One side of the driving end is a spherical roller bearing, and the other end is a cylindrical roller bearing. A balance iron is fixed on the crank arm to compensate the inertia force. There are three running connecting rods on the hardened crank pins of each crankshaft.

The lubricating oil is pressed into the connecting rod bearing through the oil circuit in the crank.

Six forged connecting rods have oil passage to small end bearing. The big end bearing system of the connecting rod is lubricated by pressure. It is an alloy split bearing composed of three components. The small end bearing bush is also pressure lubricated. It also serves as a bearing for the crosshead pin.

Connecting rod components

The connecting rod (see Figure 4) is the connecting piece between the crosshead and the crankshaft, which plays the role of converting the rotation motion of the crankshaft into the reciprocating motion of the crosshead. The connecting rod of this machine is forged with 30Mn2 steel. The big end hole is inlaid with thin-walled tile, and the thin-walled tile is poured with wear-resistant Babbitt alloy, and the small end hole is lined with an integral bronze sleeve. The connecting rod body is a "I" shaped section, and an oil hole is drilled along the axial direction of the connecting rod between the big end bearing bush and the small end copper sleeve to send oil to the small end bush to lubricate the small end bush and the crosshead slide. Connecting rod bolts and nuts are installed at connecting rod big end.