Objectives  Compared with other types of air compressor, reciprocating compressors can obtain compressed air with a higher pressure, exerting more stress on the crank connecting rod mechanism.

  Methods  This paper analyzes the inertia force and torque characteristics of the three structural forms of the star-type reciprocating air compressor. It then concludes that the air compressor has a good self-balance ability of inertial force while also reducing inertial torque to a certain extent at the same time. A virtual prototype of a crank connecting rod mechanism is built. The derivation of the force on the piston is acquired in order to construct a SPLINE curve, which is loaded on the centroid of the piston. With a flexible crankshaft, the contact force model of the IMPACT function is added between the crank pin and connecting rod.

  Results  The dynamic simulation results show that the air compressor can self-balance second-order inertial force. Clearance will decrease the vibration of the air compressor to a certain extent, but will greatly broaden the excitation frequency band.

  Conclusions  The findings of this paper can provide valuable references for the design of air compressors.