US 12,473,709 B2
Working machine
Kohei Nagao, Osaka (JP); and Yuji Fukuda, Osaka (JP)
Assigned to KUBOTA CORPORATION, Osaka (JP)
Filed by KUBOTA CORPORATION, Osaka (JP)
Filed on Mar. 9, 2023, as Appl. No. 18/119,573.
Prior Publication US 2024/0301651 A1, Sep. 12, 2024
Int. Cl. E02F 3/42 (2006.01); E02F 3/34 (2006.01); E02F 3/43 (2006.01); E02F 3/96 (2006.01); E02F 9/20 (2006.01); E02F 9/22 (2006.01); E02F 9/26 (2006.01); F15B 11/08 (2006.01); F15B 15/20 (2006.01); F15B 19/00 (2006.01)
CPC E02F 3/422 (2013.01) [E02F 3/3414 (2013.01); E02F 3/431 (2013.01); E02F 9/2004 (2013.01); E02F 9/2203 (2013.01); E02F 9/262 (2013.01); F15B 11/08 (2013.01); F15B 15/20 (2013.01); F15B 19/00 (2013.01); E02F 3/96 (2013.01); E02F 9/2285 (2013.01); E02F 9/2292 (2013.01); E02F 9/2296 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A working machine comprising:
a machine body;
at least one support member supported on the machine body and connectable to a work attachment to do work by making contact with an object to be contacted;
at least one hydraulic cylinder extendable and retractable to move the work attachment connected to the at least one support member, the at least one hydraulic cylinder including a rod-side fluid chamber and a bottom-side fluid chamber separated by a piston, the rod-side fluid chamber having a rod-side pressure area and the bottom-side fluid chamber having a bottom-side pressure area;
a control valve to control a rod-side hydraulic pressure which is a pressure of hydraulic fluid in communication with the rod-side fluid chamber of the at least one hydraulic cylinder, and a bottom-side hydraulic pressure which is a pressure of hydraulic fluid in communication with the bottom-side fluid chamber of the at least one hydraulic cylinder;
a rod-side pressure detector to detect the rod-side hydraulic pressure;
a bottom-side pressure detector to detect the bottom-side hydraulic pressure; and
a controller to calculate a cylinder thrust force corresponding to a difference between a product of the rod-side hydraulic pressure detected by the rod-side pressure detector and the rod-side pressure area minus another product of the bottom-side hydraulic pressure detected by the bottom-side pressure detector and the bottom side pressure area;
a memory to store a predetermined cylinder thrust force which achieves a predetermined contact state of the work attachment with the object, the predetermined cylinder thrust force depending on the work attachment and the work done using the work attachment, wherein
the controller is configured or programmed to read the predetermined cylinder thrust force stored in the memory, and control the control valve to bring the calculated cylinder thrust force into the predetermined cylinder thrust force.