Patent ID: 6055851
Filing Date: 2000-05-02
Classification: E02F,F04B,F15B

Abstract:
A fault diagnosis system for hydraulic pumps in a work vehicle, said work vehicle being provided with a plurality of variable displacement hydraulic pumps as said hydraulic pumps, delivery rates of which are controlled by regulators, a plurality of hydraulic actuators each of which is driven by pressurized fluid delivered from at least one of said variable displacement hydraulic pumps, a plurality of flow control valves for controlling driving of said individual hydraulic actuators, and a pressurized fluid line for communicating said at least one variable displacement hydraulic pump to a tank via at least one of said flow control valves, said at least one flow control valve being in a neutral position thereof, wherein said fault diagnosis system comprises a pressure sensor arranged on said pressurized fluid line for detecting a fluid pressure in said pressurized fluid line, maximum delivery rate designation means for successively designating maximum delivery rates of said variable displacement hydraulic pumps to corresponding ones of said regulators while said at least one variable displacement hydraulic pump is maintained in communication with said pressurized fluid line, memory means for storing a detection value by said pressure sensor with respect to each of said variable displacement hydraulic pumps, said each variable displacement hydraulic pump delivering said pressurized fluid at said maximum flow rate designated by said maximum delivery rate designation means, and fault determination means for performing on a basis of detection values by said pressure sensor a determination as to whether said variable displacement hydraulic pump for which said maximum delivery rate has been designated is operating properly or not operating properly.