Forestry underpan and hinge joint connection device thereof

A hinge joint connection device is used for connecting a front frame with a rear frame of a forestry underpan, and includes a straight pin, a connecting frame, a limiting piece, a hinge joint base and two steering hydraulic cylinders, when the forestry underpan encounters unilateral obstacle, the front frame in whole can axially rotate around the straight pin relative to the connecting frame, so as to guarantee that when the forestry underpan encounters unilateral obstacle, the front frame and the rear frame can laterally deflect relatively and independently, as a result, the center of gravity of the underpan can be stabilized, and the passing ability of the forestry underpan on an uneven riding surface is enhanced; when the forestry underpan is driven on a rugged road surface, the front frame and the rear frame can rotate relatively within a small range due to the hinge joint connection manner of the hinge joint connection device and the rear frame, so that the flexibility of the front frame and the rear frame is enhanced, and the obstacle crossing ability of the forestry underpan is enhanced; when steering is needed, the front frame and the rear frame can laterally deflect relatively under the action of the steering hydraulic cylinders on the two sides, so that steering of the vehicle is realized; the front frame and the rear frame can be automatically adjusted in multiple directions, at multiple angles and in real time; besides, the invention further provides a forestry underpan adopting the hinge joint connection device.