The function of the connecting rod is to transmit the force of the piston to the crankshaft and convert the reciprocating motion of the piston into the rotational motion of the crankshaft.

The connecting rod is composed of a connecting rod body, a connecting rod cover, a connecting rod bolt and a connecting rod bearing bush, and the connecting rod cover and the connecting rod cover are divided into a connecting rod small head, a shaft body and a connecting rod big head.

The small rod of the connecting rod is used to mount a piston pin to connect the piston. The shaft is usually made of a "work" or "H" section to reduce mass while meeting strength and stiffness requirements.

The large end of the connecting rod is connected to the connecting rod journal of the crankshaft. Generally, it is divided into two parts, and the half cut with the shaft is called a connecting rod cover, and the two are connected by a connecting rod and bolt.

The connecting rod bearing bush is installed in the large hole seat of the connecting rod and is mounted together with the connecting rod journal on the crankshaft. It is one of the most important mating pairs in the engine. Commonly used antifriction alloys are mainly white alloys, copper-lead alloys and aluminum-based alloys.

The connecting rod is an important part in the engine of the automobile and the ship. It is connected with the piston and the crankshaft. Its function is to convert the reciprocating motion of the piston into the rotational motion of the crankshaft, and transmit the force acting on the piston to the crankshaft to output power. In addition to the pressure generated by the combustion chamber gas, the connecting rod is subjected to longitudinal and lateral inertial forces. Therefore, the connecting rod operates under a complicated stress state. It is subject to both alternating tensile and compressive stresses and to bending stresses.