Reciprocating compressor crosshead pin design

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This post was last edited by Xǐzai on 2024-11-3 21:14. I came across a classification and applications of crosshead pins in a textbook, which are different from those seen in compressors these days. Is this still the design philosophy today? Crosshead pins can be divided into floating pins and fixed pins based on the way they are secured to the crosshead body. The floating pin is made as a cylinder with a uniform diameter, allowing it to rotate relative to both the pin hole and the connecting rod journal hole, thereby reducing wear. The axial positioning of the pin can be achieved by securing a spring clip in the groove of the hole seat, or by fitting the spring clip into the grooves at both ends of the crosshead pin. Axial positioning can also be achieved by covering the pin holes with clamps on both sides. Floating pins are lightweight and easy to manufacture, but they have large clearances, which result in significant shock during back-and-forth motion; therefore, they are generally suitable for medium and small compressors with a piston force of less than 55 kN. In compressors where the piston force is greater than 55 kN, the crosshead pin is generally fixed in the crosshead pin seat. At this time, a tapered pin is used for the crosshead pin, with a taper ratio generally ranging from 1/30 to 1/10 ； It has a large taper, which facilitates installation and removal, but an excessive taper will increase the size of the crosshead pin hole seat, thereby reducing the strength of the crosshead. The compression of the taper pin is achieved by the axial force generated by the pressure plate and screws, which forces the pin to fit against the conical surface of the socket hole. The lubricating oil in the crosshead pin can be introduced along the connecting rod, or via oil grooves on the slip surface through holes in the crosshead. The key on the taper pin serves primarily to prevent misalignment of the radial oil holes in the pin, thus providing positioning; it also helps to prevent rotation of the crosshead pin within its hole seat.