Hydraulic control system for mobile work machine, e.g. wheel loader or forklift truck

摘要

Operation of the hydraulic fluid control valve used for damping nodding vibrations in the machine is dependent upon the throughput volume of the hydraulic pump in the machines hydrostatic drive mechanism. The system includes a hydrostatic drive mechanism with a hydraulic pump driven by a prim. drive unit, and at least one hydraulic motor with a preferably constant fluid feed volume. At least one hydraulic cylinder (12) is used to move a work tool in the machine. A valve (11) is used to control fluid pressure between the work region (15) in the bottom end of the cylinder, a hydraulic fluid source and a tank (27). A hydraulic fluid reservoir (21) is linked to the hydraulic fluid source via a feed line (20). A control valve (42) located in the connection between the reservoir and the work region in the bottom end of the cylinder is used for damping nodding vibrations in the machine. An Independent claim is also included for a similar system where the operation of control valve is dependent upon both the throughput and rotation speed of the pump.