US 6,981,371 B2
Control device for working machine
Etsujiro Imanishi, Kobe (Japan); Naoki Sugano, Kobe (Japan); and Takao Nanjo, Kobe (Japan)
Assigned to Kobelco Construction Machinery Co., LTD, Hiroshima (Japan)
Filed on May 17, 2004, as Appl. No. 10/846,557.
Claims priority of application No. 2003-145376 (JP), filed on May 22, 2003.
Prior Publication US 2004/0231326 A1, Nov. 25, 2004
Int. Cl. F15B 11/00 (2006.01)
U.S. Cl. 60—420 11 Claims
OG exemplary drawing
 
1. A control device for a working machine comprising:
a capacity variable hydraulic pump for supplying working oil;
a controller for controlling a discharge amount of said capacity variable hydraulic pump, said controller having a dynamic emulation model of a hydraulic driving device;
a control valve for controlling the working oil discharged from said capacity variable hydraulic pump;
a hydraulic actuator adapted to be operated by the working oil from said control valve;
an operating means for operating said hydraulic actuator; and
a relief valve adapted to be operated when said working oil has a predetermined relief pressure or more,
wherein said controller estimates flow rate of the working oil passing through said relief valve from said dynamic emulation model according to an operation amount of said operating means, and controls pump flow rate of said capacity variable hydraulic pump so that flow rate estimation value of said relief value gets close to zero.