Electromotive drive device for construction machine

• US 8,972,121 B2
• Filed: 04/12/2012
• Issued: 03/03/2015
• Est. Priority Date: 04/19/2011
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Tierra Co.,Ltd. (Hitachi Construction Machinery (China) Co., Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Kurikuma, Hajime, Takishita, Tatsuo, Nakamura, Yuta
• Primary Examiner(s): Jabr, Fadey
• Assistant Examiner(s): INGRAM, THOMAS P
• Application Number:
  US13/984,396
• Publication Number:
  US 20130325235A1
• Time in Patent Office: 1,055 Days
• Field of Search: 701/50
• 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 2210/12 Buck converters
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: E02F 3/325 Backhoes of the miniature type
• 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 9/207 of the type electric propulsion units, e.g. electric motors or generators
• CPC Class Codes: E02F 9/2075 of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2091 Control of energy storage means for electrical energy, e.g. battery or capacitors energy recovery arrangements in hydraulic or pneumatic drives E02F9/2217
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/2282 Systems using center bypass type changeover valves
• CPC Class Codes: E02F 9/2285 Pilot-operated systems
• CPC Class Codes: H02J 7/14 for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
• 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 10/72 Electric energy management in electromobility

Abstract

An electromotive drive device of an electric motor-driven mini-excavator, which is capable of lengthening its operating time, includes an electric power storage device, a motor-generator, a hydraulic pump, a plurality of directional control valves which respectively control the flow of pressurized fluid, and a plurality of operating devices which respectively operate the plurality of directional control valves. The electromotive drive device is provided with a bidirectional converter which decelerates the motor-generator to an idle revolution speed when X seconds have elapsed in a state in which the plurality of directional control valves are all not operated. The bidirectional converter performs regenerative control to convert an inertial force of a rotor of the motor-generator to power and charge the electric power storage device when it decelerates the motor-generator from a standard revolution speed to the idle revolution speed.

Claims

1. An electromotive drive device for a construction machine, comprising:

an electric power storage device (7);

a motor-generator (27) which performs a transfer of power to and from the electric power storage device (7);

a hydraulic pump (29) driven by the motor-generator (27);

a plurality of hydraulic actuators (13A, 19);

a plurality of directional control valves (32, 34) which respectively control the flow of pressurized fluid from the hydraulic pump (29) to the plurality of hydraulic actuators (13A, 19); and

a plurality of operating means (31, 33) which respectively operate the plurality of directional control valves (32, 34),

wherein the electromotive drive device has

operation detecting means (41) which detects the presence or absence of operations of the plurality of directional control valves (32, 34), and

idle control means (28) which when a first time (X seconds) set in advance has elapsed in a state in which the plurality of directional control valves (32, 34) are all not operated, decelerates the motor-generator (27) controlled at a set revolution speed set in advance in such a manner that the plurality of hydraulic actuators (13A, 19) are drivable before the elapse of the first time, to a low revolution speed (N_I) set in advance lower than the set revolution speed, and

wherein when the idle control means (28) decelerates the motor-generator (27) from the set revolution speed suitable for work to the low revolution speed (N_I) at the stage of a transition of the construction machine from an operational state to a halt state, the idle control means (28) performs regenerative control to convert an inertial force of a rotor of the motor-generator (27) to power and charge the electric power storage device (7).

2. The electromotive drive device according to claim 1, including

first stop control means (28) which stops the motor-generator (27) when the motor-generator (27) is decelerated to the low revolution speed (N_I) and thereafter a second time (Y seconds) set in advance further has elapsed in the state in which the plurality of directional control valves (32, 34) are not operated,

wherein when the motor-generator (27) is stopped from a driven state thereof at the low revolution speed (N_I), the first stop control means (28) performs regenerative control to convert the inertial force of the rotor of the motor-generator (27) to power and charge the electric power storage device (7).

3. The electromotive drive device according to claim 2, including:

a gate lock lever (25) which is provided at a platform and manipulated to a prohibition release position and a prohibition position;

prohibiting means (43) which prohibits the operation of each of the plurality of directional control valves (32, 34) when the gate lock lever (25) is manipulated to the prohibition position; and

second stop control means (28) which stops the motor-generator (27) when the gate lock lever (25) is manipulated to the prohibition position,

wherein when the motor-generator (27) is stopped, the second stop control means (28) performs regenerative control to convert the inertial force of the rotor of the motor-generator (27) to power and charge the electric power storage device (7).

4. The electromotive drive device according to claim 1, including:

a gate lock lever (25) which is provided at a platform and manipulated to a prohibition release position and a prohibition position;

prohibiting means (43) which prohibits the operation of each of the plurality of directional control valves (32, 34) when the gate lock lever (25) is manipulated to the prohibition position; and

second stop control means (28) which stops the motor-generator (27) when the gate lock lever (25) is manipulated to the prohibition position,

wherein when the motor-generator (27) is stopped, the second stop control means (28) performs regenerative control to convert the inertial force of the rotor of the motor-generator (27) to power and charge the electric power storage device (7).

5. An electromotive drive device for a construction machine, comprising:

an electric power storage device (7);

a motor-generator (27) which performs a transfer of power to and from the electric power storage device (7);

a hydraulic pump (29) driven by the motor-generator (27);

a plurality of hydraulic actuators (13A, 19);

a plurality of directional control valves (32, 34) which respectively control the flow of pressurized fluid from the hydraulic pump (29) to the plurality of hydraulic actuators (13A, 19); and

a plurality of operating means (31, 33) which respectively operate the plurality of directional control valves (32, 34),

wherein the electromotive drive device includes;

operation detecting means (41) which detects the presence or absence of operation of each of the plurality of directional control valves (32, 34), and

stop control means (28A) which when a predetermined time (X seconds) set in advance has elapsed in a state in which the plurality of directional control valves (32, 34) are all not operated, stops the motor-generator (27) controlled at a set revolution speed set in advance in such a manner that the plurality of hydraulic actuators (13A, 19) are drivable before the elapse of the predetermined time, and

wherein when the stop control means (28A) stops the motor-generator (27) from a driven state thereof at the set revolution speed suitable for work at the stage of a transition of the construction machine from an operational state to a halt state, the stop control means (28A) performs regenerative control to convert an inertial force of a rotor of the motor-generator (27) to power and charge the electric power storage device (7).

6. An electromotive drive device for a construction machine, comprising:

an electric power storage device (7);

a motor-generator (27) which performs a transfer of power to and from the electric power storage device (7);

a hydraulic pump (29) driven by the motor-generator (27);

a plurality of hydraulic actuators (13A, 19);

a plurality of directional control valves (32, 34) which respectively control the flow of pressurized fluid from the hydraulic pump (29) to the plurality of hydraulic actuators (13A, 19); and

a plurality of operating means (31, 33) which respectively operate the plurality of directional control valves (32, 34),

wherein the electromotive drive device includes;

a gate lock lever (25) which is provided at a platform and manipulated to a prohibition release position and a prohibition position;

prohibiting means (43) which prohibits the operation of each of the plurality of directional control valves (32, 34) when the gate lock lever (25) is manipulated to the prohibition position; and

stop control means (28;

28A) which when the gate lock lever (25) is manipulated from the prohibition release position to the prohibition position, stops the motor-generator (27) controlled at a set revolution speed set in advance in such a manner that the plurality of hydraulic actuators (13A, 19) are drivable, and

wherein when the stop control means (28;

28A) stops the motor-generator (27) from a driven state thereof at the set revolution speed suitable for work at the stage of a transition of the construction machine from an operational state to a halt state, the stop control means (28;

28A) performs regenerative control to convert an inertial force of a rotor of the motor-generator (27) to power and charge the electric power storage device (7).