WORKING MACHINE

• US 20110093150A1
• Filed: 04/10/2009
• Published: 04/21/2011
• Est. Priority Date: 04/11/2008
• Status: Active Grant

• Current Assignee: Sumitomo Heavy Industries Limited, Sumitomo (S.H.I.) Construction Machinery Co., Ltd. (Sumitomo Heavy Industries Limited)
• Original Assignee: Sumitomo Heavy Industries Limited, Sumitomo (S.H.I.) Construction Machinery Co., Ltd. (Sumitomo Heavy Industries Limited)
• Inventors: Yanagisawa, Makoto, Kanbayashi, Hideaki
• Granted Patent: US 8,798,875 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/20 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 1/02 to electric heating circuits
• CPC Class Codes: B60L 1/20 Energy regeneration from auxiliary equipment
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 2200/42 Fork lift trucks
• CPC Class Codes: B60L 2210/12 Buck converters
• CPC Class Codes: B60L 2210/14 Boost converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2250/12 by confirmation, e.g. of the input
• CPC Class Codes: B60L 2250/22 by presence detection
• CPC Class Codes: B60L 2250/24 by lever actuation
• CPC Class Codes: B60L 3/003 relating to inverters
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0061 : relating to electrical machines
• CPC Class Codes: B60L 50/40 : using propulsion power supplied by capacitors
• 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 58/25 : by controlling the electric load
• CPC Class Codes: B60L 7/14 : for vehicles propelled by ac motors
• CPC Class Codes: B60W 10/08 : including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 : for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 : Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 : in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/0638 : Engine speed
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60Y 2200/15 : Fork lift trucks, Industrial trucks
• CPC Class Codes: B60Y 2200/25 : Track vehicles
• CPC Class Codes: B60Y 2200/41 : Construction vehicles, e.g. graders, excavators
• CPC Class Codes: B60Y 2200/412 : Excavators
• CPC Class Codes: B60Y 2400/114 : Super-capacities
• CPC Class Codes: B66C 1/04 : by magnetic means
• CPC Class Codes: B66C 13/18 : Control systems or devices exclusively for rope, cable, or chain winding mechanisms B66D1/40
• CPC Class Codes: B66F 9/20 : Means for actuating or controlling masts, platforms, or forks power take-off from vehicle transmissions, combined with vehicle propulsion systems B60K
• CPC Class Codes: E02F 9/20 : Drives; Control devices gearings in general F16H; controlling in general G05; electric multi-motor drives H02K, H02P
• CPC Class Codes: H05K 7/20927 : Liquid coolant without phase change
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• 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

A working machine includes: a first electric motor used for work; a second electric motor used for applications other than work; a first inverter circuit connected to the first electric motor; a second inverter circuit connected to the second electric motor; a battery connected to the first and second inverter circuits; and a control unit that drives the first and second inverter circuits. The control unit has a discharge mode to discharge electric power stored in the battery, and discharges the battery by stopping the first inverter circuit while driving the second inverter circuit in order to make the second electric motor perform electric operation in the discharge mode. Accordingly, since the state of charge is reduced, the life of a capacitor can be increased.

Claims

1. A working machine comprising:

a first electric motor used for work;

a second electric motor used for applications other than work;

a first inverter circuit connected to the first electric motor;

a second inverter circuit connected to the second electric motor;

a battery connected to the first and second inverter circuits; and

a control unit that drives the first and second inverter circuits,

wherein the control unit has a discharge mode to discharge electric power stored in the battery, and discharges the battery by stopping the first inverter circuit while driving the second inverter circuit in order to make the second electric motor perform electric operation in the discharge mode.

2. The working machine according to claim 1,

wherein the first electric motor is an electric motor for operation driven by operation of an operator,

one end of the first inverter circuit is connected to a terminal of the electric motor for operation,

the battery is connected to the other end of the first inverter circuit through a DC voltage converter,

a coolant circulation system, which is provided to cool the first inverter circuit and the DC voltage converter and which includes a pump to circulate coolant and an electric motor to cool as the second electric motor that drives the pump, is further provided,

the second inverter circuit is connected between the electric motor to cool and the DC voltage converter,

the control unit drives the first and second inverter circuits and the DC voltage converter, and

the control unit discharges the battery by stopping the first inverter circuit while driving the second inverter circuit in order to make the electric motor to cool consume electric power in the discharge mode.

3. The working machine according to claim 2,

wherein the DC voltage converter has a step-up and step-down type switching control system including switching elements for step-up and step-down and a diode connected in parallel to each of the switching elements, and

the control unit does not drive the switching elements in the discharge mode.

4. The working machine according to claim 2, further comprising:

an internal combustion engine;

a motor generator which is connected to the internal combustion engine and which generates electric power with a driving force of the internal combustion engine and assists a driving force of the internal combustion engine with its own driving force; and

a third inverter circuit connected between the motor generator and the DC voltage converter,

wherein the control unit stops the third inverter circuit in the discharge mode.

5. The working machine according to claim 2,

wherein the coolant circulation system further cools the electric motor for operation.

6. The working machine according to claim 1,

wherein the second electric motor is a motor generator to assist an engine,

the battery performs supplying of electric power to the motor generator or charging of regenerative power,

the second inverter circuit performs driving control of the motor generator,

the control unit includes a driving level determining section that determines a driving level of the engine or the operating element, and

the second inverter circuit performs electric operation of the motor generator when the driving level determining section determines that the driving level of the engine or an operating element is equal to or lower than a predetermined level.

7. The working machine according to claim 6,

wherein the second inverter circuit performs electric driving of the motor generator so that a state of charge of the battery is maintained at a predetermined level or higher.

8. The working machine according to claim 6,

wherein the driving level determining section is configured to determine the driving level of the engine on the basis of an operating state of the operating element, determine the driving level of the engine according to the number of revolutions of the engine, determine the driving level of the operating element according to the amount of operation input to an operating device of the operating element, determine the driving level of the engine or the operating element according to an operating state of a gate lock lever to prohibit a driver from leaving a driver'"'"'s seat, or determine the driving level of the engine or the operating element according to an operation position of an ignition switch.

9. The working machine according to claim 1,

wherein a plurality of operating elements including a motor generator to assist an engine and a capacitor, which performs supplying of electric power to the motor generator or charging of regenerative power, is driven by an electromotive force or a hydraulic force,

a driving control section, which performs driving control of the motor generator, and a driving level determining section, which determines a driving level of the engine or the operating element, are provided, and

the driving control section performs electric operation of the motor generator when the driving level determining section determines that the driving level of the engine or the operating element is equal to or lower than a predetermined level.

10. The working machine according to claim 9,

wherein the driving control section performs electric driving of the motor generator using electric power stored in the capacitor.

11. The working machine according to claim 10,

wherein the driving control section performs electric driving of the motor generator so that a state of charge of the capacitor is maintained at a predetermined level or higher.

12. The working machine according to claim 9,

wherein the driving level determining section is configured to determine the driving level of the engine on the basis of an operating state of the operating element, and

the driving control section performs electric operation of the motor generator when the driving level determining section determines that the driving level of the engine is equal to or lower than a predetermined level on the basis of the operating state of the operating element.

13. The working machine according to claim 9,

wherein the driving level determining section is configured to determine the driving level of the engine according to the number of revolutions of the engine, and

the driving control section performs electric operation of the motor generator when the driving level determining section determines that the driving level of the engine is equal to or lower than a predetermined level on the basis of the number of revolutions of the engine.

14. The working machine according to claim 9,

wherein the driving level determining section is configured to determine the driving level of the operating element according to the amount of operation input to an operating device of the operating element, and

the driving control section performs electric operation of the motor generator when the driving level determining section determines that the driving level of the operating element is equal to or lower than a predetermined level on the basis of the amount of operation input to the operating device of the operating element.

15. The working machine according to claim 9,

wherein the driving level determining section is configured to determine the driving level of the engine or the operating element according to an operating state of a gate lock lever to prohibit a driver from leaving a driver'"'"'s seat, and

the driving control section performs electric operation of the motor generator when the driving level determining section determines that the driving level of the engine or the operating element is equal to or lower than a predetermined level on the basis of the operating state of the gate lock lever.

16. The working machine according to claim 9,

wherein the driving level determining section is configured to determine the driving level of the engine or the operating element according to an operation position of an ignition switch, and

the driving control section performs electric operation of the motor generator when the driving level determining section determines that the driving level of the engine or the operating element is equal to or lower than a predetermined level on the basis of the operation position of the ignition switch.