US 12,227,920 B2
Construction machine
Ryota Kameoka, Ishioka (JP); Shinji Nishikawa, Kasumigaura (JP); and Akihiro Narazaki, Tsukuba (JP)
Assigned to HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
Appl. No. 17/760,513
Filed by HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
PCT Filed Dec. 10, 2020, PCT No. PCT/JP2020/046142
§ 371(c)(1), (2) Date Mar. 15, 2022,
PCT Pub. No. WO2021/131761, PCT Pub. Date Jul. 1, 2021.
Claims priority of application No. 2019-238919 (JP), filed on Dec. 27, 2019.
Prior Publication US 2022/0349153 A1, Nov. 3, 2022
Int. Cl. E02F 9/24 (2006.01); E02F 3/43 (2006.01); E02F 9/08 (2006.01); E02F 9/20 (2006.01); E02F 9/22 (2006.01); E02F 9/26 (2006.01)
CPC E02F 9/24 (2013.01) [E02F 3/435 (2013.01); E02F 9/0866 (2013.01); E02F 9/2033 (2013.01); E02F 9/2203 (2013.01); E02F 9/2232 (2013.01); E02F 9/2246 (2013.01); E02F 9/226 (2013.01); E02F 9/2267 (2013.01); E02F 9/262 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A construction machine comprising:
an engine mounted on a machine body;
a variable displacement hydraulic pump driven by the engine;
a plurality of hydraulic actuators driven by an hydraulic fluid delivered from the hydraulic pump;
a plurality of directional control valves that control the flow rates of the hydraulic fluid supplied to the hydraulic actuators from the hydraulic pump;
an obstacle sensor that senses an obstacle in surroundings of the machine body; and
a controller that performs operation limiting control for limiting operation of the machine body when the obstacle is sensed by the obstacle sensor,
wherein the controller is configured to:
perform the operation limiting control by performing control for reducing a speed of the engine when the machine body does not require engine speed increase control for increasing the speed of the engine and when the obstacle is sensed by the obstacle sensor, and
perform the operation limiting control by performing supply flow rate reduction control for reducing the flow rates of the hydraulic fluid supplied to the plurality of hydraulic actuators from the hydraulic pump when the machine body requires the engine speed increase control and when the obstacle is sensed by the obstacle sensor.