Hydraulic steering system for engineering machinery

Abstract

The invention discloses a hydraulic steering system for engineering machinery, and belongs to the technical field of hydraulic systems for the engineering machinery. The system comprises a steering pump and steering cylinders controlling the steering of the engineering machinery through a steering gear, wherein a priority valve is communicated with an oil way between the steering gear and the steering pump; a first hydraulic control reversing valve is communicated in series in an oil way between a third oil port of the steering gear and a second oil port of the priority valve; a shuttle valve, a second hydraulic control reversing valve and an engine-driven reversing valve are communicated in series in an oil way between the hydraulic control port of the first hydraulic control reversing valve and the first oil port of the steering pump; limiting blocks are respectively arranged on both sides, corresponding to the engine-driven reversing valve, of a vehicle frame of the engineering machinery. A hydraulic circuit control manner disclosed by the invention is simple and reliable. During the steering at a limit position of the cylinders, the system does not have a spill loss and hydraulic impact on the vehicle frame by the steering cylinders at the limit position is eliminated, so that energy is saved, rocking does not occur when the steering is finished, and the comfort of the whole vehicle is increased.

Description

technical field [0001] The invention relates to the technical field of engineering machinery hydraulic systems, in particular to an engineering machinery hydraulic steering system. Background technique [0002] Existing construction machinery hydraulic steering system, such as Figure 5 As shown, it includes a steering pump 14 and a steering cylinder 11 that controls the steering of construction machinery through a steering gear 12, and a priority valve 13 is communicated on the oil circuit between the steering gear 12 and the steering pump 14; wherein the first oil port of the steering pump 14 14a communicates with the fourth oil port 13d of the priority valve 13, the first oil port 13a of the priority valve 13 communicates with the fourth oil port 12d of the steering gear 12, and the second oil port 13b of the priority valve 13 passes the load pressure LS signal The oil passage communicates with the third oil port 12c of the steering gear 12, the first oil port 12a and the...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a hydraulic steering system for engineering machinery, which can solve the problem of shaking caused by the large impact force of the oil cylinder on the frame, resulting in loose and easily damaged parts of the engineering machinery and the movement of the oil cylinder to the limit When the position is high, high pressure and large flow overflow will cause energy loss and accelerate oil heating.

Images