Smooth and finish the crankpin to roundness.

把曲柄销磨光并精加工到正圆.

The connecting rod carries the power thrusts from the piston to the crankpin. At the same time, the rod is in eccentric motion.

连杆的作用是将活塞承受的压力传给连杆轴颈。同时，连杆做偏心运动。