Control system for construction machine

• US 9,228,323 B2
• Filed: 02/23/2011
• Issued: 01/05/2016
• Est. Priority Date: 02/26/2010
• Status: Expired due to Fees

• Current Assignee: KYB Corp.
• Original Assignee: Kayaba Industry Company Limited
• Inventors: Kawasaki, Haruhiko, Egawa, Masahiro
• Primary Examiner(s): Wiehe, Nathaniel
• Assistant Examiner(s): Nguyen, Dustin T
• Application Number:
  US13/577,510
• Publication Number:
  US 20120304630A1
• Time in Patent Office: 1,777 Days
• Field of Search: None
• US Class Current: 1/1
• 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 9/2282 Systems using center bypass type changeover valves
• CPC Class Codes: E02F 9/2285 Pilot-operated systems
• CPC Class Codes: E02F 9/2292 Systems with two or more pumps
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: F15B 11/17 using two or more pumps
• CPC Class Codes: F15B 2211/20546 variable capacity
• CPC Class Codes: F15B 2211/20576 with multiple pumps
• CPC Class Codes: F15B 2211/265 Control of multiple pressure sources
• CPC Class Codes: F15B 2211/3116 the pump port being open in the centre position, e.g. so-called open centre
• CPC Class Codes: F15B 2211/88 Control measures for saving energy

Abstract

A control system for construction machine includes a main pump; a circuit system which includes a plurality of operation valves; a boom cylinder which is connected to a specific valve; one passage which allows communication between the specific operation valve and a piston-side chamber; another passage which allows communication between the specific operation valve and a rod-side chamber; a hydraulic motor which rotates by the action of return oil from the piston-side chamber; a generator; and a valve mechanism which is provided in the one passage communicating with the piston-side chamber of the boom cylinder, introduces the return oil from the piston-side at the time of descent as a regeneration flow to the hydraulic motor and introduces the return oil as a recovery flow to the rod-side chamber if necessary by causing the return oil to flow into the other passage.

Claims

1. A control system for construction machine, comprising:

a main pump;

a circuit system which includes a plurality of operation valves connected to the main pump;

a boom cylinder which includes a piston-side chamber and a rod-side chamber, and which is connected to a specific one of the plurality of operation valves;

one passage which allows communication between the specific operation valve and the piston-side chamber of the boom cylinder;

another passage which allows communication between the specific operation valve and the rod-side chamber of the boom cylinder;

a hydraulic motor which rotates by the action of return oil from the piston-side chamber of the boom cylinder;

a generator which generates power by a rotational force of the hydraulic motor;

a battery which stores power generated by the generator; and

a valve mechanism which introduces the return oil directly from the piston-side chamber of the boom cylinder through the one passage at the time of descent as a regeneration flow to the hydraulic motor, and introduces the return oil as a recovery flow to the rod-side chamber of the boom cylinder, if necessary, through the other passage.

2. The control system according to claim 1, wherein:

the valve mechanism has a control function of controlling a supply flow rate to the hydraulic motor according to an operating amount of the specific operation valve at the time of a control to lower the boom cylinder by operating the specific operation valve.

3. The control system according to claim 1, wherein:

the valve mechanism supplies return oil from the boom cylinder as a recovery flow to the rod-side chamber of the boom cylinder when a lowering speed command of the boom cylinder is equal to or higher than a set speed at the time of a control to lower the boom cylinder by operating the specific operation valve.

4. The control system according to claim 1, wherein:

the valve mechanism connects a pilot pressure source to a pilot chamber via a proportional electromagnetic valve and causes an opening of the proportional electromagnetic valve to be controlled by a controller by causing a spring force of a spring to act on a side facing the pilot chamber.

5. The control system according to claim 1, wherein the valve mechanism includes:

a regeneration flow control valve switchable between a first normal position where the one passage is opened while the communication with the hydraulic motor is cut off and a first switched position where the communication with the hydraulic motor is opened while the one passage is throttle controlled; and

a recovery flow control valve which is provided at a recovery passage which allows the piston-side chamber and the rod-side chamber of the boom cylinder to communicate, kept in a closed state at a second normal position and kept in an open state at a second switched position.

6. The control system according to claim 1, wherein the valve mechanism is disposed in the one passage between the piston-side chamber of the boom cylinder and the specific operation valve.

7. The control system according to claim 1, wherein

the valve mechanism include a pilot chamber and a spring, said pilot chamber being connected to a pilot pressure source, said spring providing a spring force on a side opposite to said pilot chamber, and

a switching timing of a position of a valve included in the valve mechanism is changed depending on an amount of the spring force of the spring.

8. The control system according to claim 7, wherein an opening of said valve included in the valve mechanism is controlled by a pilot pressure of the pilot chamber included in the valve mechanism.

9. The control system according to claim 7, further comprising:

a proportional electromagnetic valve through which said pilot chamber included in the valve mechanism connects the pilot pressure source, and

a controller which controls an opening of the proportional electromagnetic valve,

wherein a pilot pressure of the pilot chamber included in the valve mechanism is controlled by said controller through said proportional electromagnetic valve.

10. The control system according to claim 9, wherein the regeneration flow control valve switches the position from said first normal position to said first switched position before the recovery flow control valve switches the position from the second normal position to said second switched position.

11. The control system according to claim 9, wherein

the regeneration flow control valve include a first pilot chamber and a first spring which provides a first spring force on a side opposite to said first pilot chamber,

the recovery flow control valve include a second pilot chamber and a second spring which provides a second spring force on a side opposite to said second pilot chamber, and

said first spring force of the first spring is smaller than said second spring force of the second spring.

12. The control system according to claim 1, wherein the valve mechanism includes:

a regeneration flow control valve adapted to be switched between a first normal position and a first switched position wherein, in the first normal position, the regeneration flow control valve opens the one passage while closing a motor passage which is connected to the hydraulic motor and in the first switched position, the regeneration flow control valve controls an amount of flow passing through the one passage while allowing the return oil to flow to the hydraulic motor through the motor passage; and

a recovery flow control valve adapted to be switched between a second normal position and a second switched position, wherein in the second normal position, the recovery flow control valve closes a recovery passage, and in the second switched position, the recovery flow control valve controls an amount of a flow of the recovery passage and allows said recovery passage to flow the return oil from the piston-side chamber to the rod-side chamber of the boom cylinder.

13. The control system according to claim 12, wherein

in the first switched position, the regeneration flow control valve controls an amount of each flow of the one passage and the motor passage which is connected to the hydraulic motor depending on a lowering speed of the boom cylinder.

14. The control system according to claim 12, wherein said recovery passage connects the piston-side chamber of the boom cylinder to the other passage.

15. A control system for construction machine, comprising:

a main pump;

a circuit system which includes a plurality of operation valves connected to the main pump;

a boom cylinder which includes a piston-side chamber and a rod-side chamber, and which is connected to a specific one of the plurality of operation valves;

one passage which allows communication between the specific operation valve and the piston-side chamber of the boom cylinder;

another passage which allows communication between the specific operation valve and the rod-side chamber of the boom cylinder;

a hydraulic motor which rotates by the action of return oil from the piston-side chamber of the boom cylinder;

a generator which generates power by a rotational force of the hydraulic motor;

a battery which stores power generated by the generator; and

a valve mechanism which receives the return oil from the piston-side chamber of the boom cylinder through the one passage without passing through any other valves at the time of descent as a regeneration flow and provides said return oil to the hydraulic motor, and introduces said return oil as a recovery flow to the rod-side chamber of the boom cylinder, if necessary, through the other passage.

16. The control system according to claim 15, wherein the valve mechanism is disposed in the one passage between the piston-side chamber of the boom cylinder and the specific operation valve.