| 摘要 |
PCT No. PCT/JP97/02771 Sec. 371 Date Sep. 3, 1998 Sec. 102(e) Date Sep. 3, 1998 PCT Filed Aug. 7, 1997 PCT Pub. No. WO98/06946 PCT Pub. Date Feb. 19, 1998This invention relates to a fault diagnosis system for hydraulic pumps in a work vehicle, which is economical and permits sure identification of one or more trouble-developed ones of the hydraulic pumps. Pressure sensors 61-64 are arranged on pressurized fluid lines 30,40, which extend to a tank T from points immediately out of center bypasses of flow control valves 21,231-234,451-454,26 communicated to hydraulic pumps 1-6. Solenoid-operated directional control valves 51-56 are interposed in input circuits of individual regulators 11-16 so that, upon excitation, a pressure of a pilot pump 7 is introduced into the regulators 11-16. When all the flow control valves are brought into neutral positions thereof and a determination is instructed through a switch 80, one of the solenoid-operated directional control valves is excited by a signal from a processor 70 so that pressurized fluid is delivered at a maximum flow rate from the corresponding hydraulic pump. A detection value of the corresponding pressure sensor at this time is translated into a flow rate, which is then stored. These procedures are performed with respect to the individual hydraulic pumps successively. Based on a flow rate obtained in every determination, a fault diagnosis of the corresponding particular hydraulic pump is performed. |
