CONTROL SYSTEM FOR CONSTRUCTION MACHINE

• US 20120304630A1
• Filed: 02/23/2011
• Published: 12/06/2012
• Est. Priority Date: 02/26/2010
• Status: Active Grant

• Current Assignee: KYB Corp.
• Original Assignee: Kayaba Industry Company Limited (KYB Corp.)
• Inventors: Kawasaki, Haruhiko, Egawa, Masahiro
• Granted Patent: US 9,228,323 B2
• Time in Patent Office: Days
• US Class Current: 60/325
• 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 including operation valves; a boom cylinder being connected to a specific operation valve; one passage allowing communication between the specific operation valve and a piston-side chamber; another passage allowing communication between the specific operation valve and a rod-side chamber; a hydraulic motor rotating by the action of return oil from the piston-side chamber; a generator generating power by a rotational force of the hydraulic motor; a battery storing power generated by the generator; and a valve mechanism being provided in the one passage communicating with the piston-side chamber, introducing the return oil from the piston-side chamber at the time of descent as a regeneration flow to the hydraulic motor and introducing 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 is connected to a specific one of the plurality of operation valves;

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

another passage which allows communication between the specific operation valve and a 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 is provided in the one passage communicating with the piston-side chamber of the boom cylinder, introduces the return oil from the piston-side chamber of the boom cylinder 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 by causing the return oil to flow into 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 the operating amount of the 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 the 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 which is made switchable to a normal position where the one passage is opened to cut off communication with the hydraulic motor and a switch 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 the normal position and kept in an open state at the switch position.