US 12,168,858 B2
Battery-operated work machine
Yuki Hirose, Rittou (JP); Masayuki Yunoue, Koka (JP); Tatsuo Takishita, Koka (JP); Wataru Takagi, Kusatsu (JP); and Takuya Nomura, Rittou (JP)
Assigned to Hitachi Construction Machinery Tierra Co., Ltd., Koka (JP)
Appl. No. 17/276,747
Filed by Hitachi Construction Machinery Tierra Co., Ltd., Koka (JP)
PCT Filed Mar. 16, 2020, PCT No. PCT/JP2020/011559
§ 371(c)(1), (2) Date Mar. 16, 2021,
PCT Pub. No. WO2020/196062, PCT Pub. Date Oct. 1, 2020.
Claims priority of application No. 2019-059413 (JP), filed on Mar. 26, 2019.
Prior Publication US 2022/0049467 A1, Feb. 17, 2022
Int. Cl. E02F 9/22 (2006.01); B60L 15/20 (2006.01); B60L 50/60 (2019.01); B60L 58/12 (2019.01); E02F 3/32 (2006.01); E02F 3/96 (2006.01); E02F 9/26 (2006.01)
CPC E02F 9/2253 (2013.01) [B60L 15/20 (2013.01); B60L 50/60 (2019.02); B60L 58/12 (2019.02); B60L 2200/40 (2013.01); B60L 2240/421 (2013.01); B60L 2250/10 (2013.01); B60L 2250/16 (2013.01); B60L 2260/20 (2013.01); E02F 3/325 (2013.01); E02F 3/964 (2013.01); E02F 9/2285 (2013.01); E02F 9/2292 (2013.01); E02F 9/26 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A battery-operated work machine comprising:
a main body;
a front work implement attached to the main body;
a battery;
an electric motor driven by electric power of the battery;
an inverter that controls the electric motor;
a target revolution speed instruction device that gives an instruction on a target revolution speed of the electric motor;
a hydraulic pump driven by the electric motor;
an actuator to which delivery fluid of the hydraulic pump is supplied to drive the front work implement;
a traveling motor that is configured from a variable displacement type hydraulic motor to which delivery fluid of the hydraulic pump is supplied to cause the main body to travel;
a traveling mode instruction device that gives an instruction on a traveling mode of the main body, the traveling mode being either a travel first speed in which the main body travels at a low speed or a travel second speed in which a battery consumption by driving of the traveling motor is higher than the first speed travel and the main body travels at a high speed; and
a controller that is configured to control the inverter such that a revolution speed of the electric motor coincides with the target revolution speed, and switches the traveling motor to a travel first speed side with which a displacement volume is a large volume in a case where an instruction on the travel first speed is given by the traveling mode instruction device, and switches the traveling motor to a travel second speed side with which the displacement volume is a small volume in a case where an instruction on the travel second speed is given by the traveling mode instruction device, wherein
the controller is configured to control the inverter such that the revolution speed of the electric motor is kept at the target revolution speed thereby keeping the hydraulic pump driven, and switch the traveling motor to the travel first speed side thereby making the displacement volume of the traveling motor large, irrespective of an input from the traveling mode instruction device, in a case where a remaining capacity of the battery becomes lower than a first threshold value set in advance.