WORK MACHINE

• US 20140371995A1
• Filed: 12/18/2012
• Published: 12/18/2014
• Est. Priority Date: 12/22/2011
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Udagawa, Tsutomu, Fujishima, Kazuo, Satake, Hidetoshi, Kunitomo, Yuichi, Ishikawa, Koji
• Granted Patent: US 9,212,469 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: E02F 9/123 Drives or control devices specially adapted therefor E02F9/125 and E02F9/128 take precedence
• CPC Class Codes: E02F 9/2025 Particular purposes of control systems not otherwise provided for E02F3/16, E02F3/26, sub-groups of E02F3/43, E02F3/651, sub-groups of E02F3/84, E02F3/907, E02F5/145 take precedence
• CPC Class Codes: E02F 9/2037 Coordinating the movements of the implement and of the frame
• CPC Class Codes: E02F 9/2058 Electric or electro-mechanical or mechanical control devices of vehicle sub-units for vehicles in general B60W
• CPC Class Codes: E02F 9/2095 Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans control of hydraulic driven equipment E02F9/22
• CPC Class Codes: E02F 9/2285 Pilot-operated systems
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

There is provided a hydraulic excavator including a hydraulic pump (6) driven by an engine (7), a boom cylinder (3a) driven by hydraulic fluid delivered from the hydraulic pump (6), a swing motor (16) driven electrically, an operating device (4A) for operating the boom cylinder (3a), an operating device (4B) for operating the swing motor (16), and a vehicle body controller (11) which limits the power of the swing motor (16) in accordance with the operation amount of the operating device (4A) when the two operating devices (4A, 4B) are operated in combination. The power limit value of the swing motor (16) varies depending on the output of the engine (7). This allows a good operational feeling to be retained in combined operation regardless of the operating state of the engine.

Claims

1. A work machine comprising:

an engine (7);

a hydraulic pump (6) driven by the engine;

a hydraulic actuator (3a) driven by hydraulic fluid delivered by the hydraulic pump;

an electric actuator (16) driven electrically;

a first operating device (4A) which operates the hydraulic actuator;

a second operating device (4B) which operates the electric actuator, and

a control device (11) which controls a force or a torque generated by the electric actuator and a speed of the electric actuator to be lower than respective limit values of the force or the torque and the speed, wherein

the control device calculates a power limit value of the electric actuator in accordance with the operation amount of the first operating device when the first and second operating devices are operated in combination, and

the control device maintains the power of the electric actuator at the power limit value when the force or the torque generated by the electric actuator and the speed of the electric actuator are smaller than the respective limit values.

4. A work machine according to claim 1, wherein

the first operating device is operable in two directions, and

the power limit value of the electric actuator has characteristics corresponding to a direction in which the first operating device is operated.

5. A work machine according to claim 1, wherein

the electric actuator is a motor (16), and

the power limit value of the electric actuator is set independently depending on whether the motor is in a powering or regenerative operation.

2-3. -3. (canceled)