BULLDOZING HYDRAULIC SYSTEM WITH BULLDOZING BLADE FLOATING FUNCTION AND EXCAVATOR

Disclosed are a bulldozing hydraulic system with a bulldozing blade floating function and an excavator. The bulldozing hydraulic system comprises a load-sensitive pump, a bulldozing blade oil cylinder, a load-sensitive valve and a station switching mechanism. The load-sensitive valve comprises a four-position reversing valve. When the four-position reversing valve is at a first station, oil enters a small-cavity A port of the bulldozing blade oil cylinder and returns from a large-cavity B port, and a bulldozing blade is controlled to ascend; when the four-position reversing valve is located at a second station, oil enters the large-cavity B port of the bulldozing blade oil cylinder and returns from the small-cavity A port, and the bulldozing blade is controlled to descend; and when the four-position reversing valve is at a third station, the small-cavity A port and the large-cavity B port of the bulldozing blade oil cylinder are communicated with an oil tank, such that the bulldozing blade floating function is realized. The invention solves the problem that an existing excavator bulldozing blade does not have a floating function; a reversing valve integration mode is adopted, such that a high-voltage electromagnetic reversing hydraulic element does not need to be externally connected between the reversing valve and the bulldozing blade oil cylinder; and due to element integration, space is saved, and cost is reduced.