US 11,753,799 B2
Work vehicle
Yasunori Miyamoto, Tsuchiura (JP); and Tetsuji Tanaka, Abiko (JP)
Assigned to HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
Appl. No. 17/638,296
Filed by HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
PCT Filed Mar. 15, 2021, PCT No. PCT/JP2021/010316
§ 371(c)(1), (2) Date Feb. 25, 2022,
PCT Pub. No. WO2021/193187, PCT Pub. Date Sep. 30, 2021.
Claims priority of application No. 2020-051505 (JP), filed on Mar. 23, 2020.
Prior Publication US 2022/0356677 A1, Nov. 10, 2022
Int. Cl. E02F 9/22 (2006.01); E02F 9/26 (2006.01); F15B 15/20 (2006.01); E02F 3/28 (2006.01)
CPC E02F 9/2228 (2013.01) [E02F 9/2267 (2013.01); E02F 9/26 (2013.01); F15B 15/20 (2013.01); E02F 3/283 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A work vehicle comprising:
a work device attached to a vehicle body;
a hydraulic actuator configured to drive the work device;
a hydraulic pump driven by an engine to supply the hydraulic actuator with hydraulic oil;
a directional control valve configured to control a flow of the hydraulic oil discharged from the hydraulic pump and supplied to the hydraulic actuator;
a hydraulic oil tank for storing the hydraulic oil;
a solenoid control valve configured to supply the directional control valve with a control pressure for controlling and switching the directional control valve;
an electric operation device for operating the work device; and
a controller configured to output a control signal corresponding to an operation amount of the electric operation device to the solenoid control valve,
wherein
the work vehicle includes:
a pressure sensor configured to detect a discharge pressure of the hydraulic pump; and
a rotational speed sensor configured to detect a rotational speed of the engine,
the directional control valve includes a neutral position for causing the hydraulic oil discharged from the hydraulic pump to return to the hydraulic oil tank, and
the controller is configured to, in a case where the discharge pressure detected by the pressure sensor is equal to or more than a relief pressure in a drive circuit of the hydraulic actuator, and the rotational speed detected by the rotational speed sensor is less than a low idle rotational speed that is a rotational speed in a state where the engine is running at a low idle speed, execute restriction of output of the control signal to the solenoid control valve so as to cause the directional control valve to be switched to the neutral position.