Automatic visual inspection device for assembly of engine piston

The invention provides an automatic visual inspection device for the assembly of an engine piston, which device comprises a visual system, a programmable logic controller and an alarm device. The visual system consists of cameras, an image capture card and a computer; the cameras are respectively arranged above each piston mounting hole in an engine body; each camera is connected with the image capture card; the image capture card is connected with the computer; and the computer and the alarm device are both connected with the programmable logic controller. Various information of an assembled piston is set in the computer, and when the piston is arranged in a cylinder body, the visual system checks whether the information on the piston is completely the same as the set information, sends a signal to the programmable logic controller and controls the engine body to enter a next station so that the piston is delivered to a repair region to be repaired and an alarm is given. According to the device, by the visual system, the operational process of an engine is detected during the assembly of the piston, and the automatic visual inspection device has a simple structure, short response time, small error and high precision, so that the device can well realize the automatic error-proof inspection of the engine piston.