US 2008/0155977 A1Published application

Apparatus for easing impact on boom of excavator and method of controlling the same

AssigneeVolvo Construction Equipment Holding Sweden AB

InventorsDong Soo Kim, Jae Hoon Lee, Chun Seung Lee, Jae Hong Kim, Joong Seon Joh, Eun Tae Jeung

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Abstract

An apparatus for easing an impact on a boom of an excavator and a method of controlling the same are disclosed, which can minimize the vibration occurring in the boom due to the impact on a boom cylinder by actively controlling an amount of hydraulic fluid being supplied to the boom cylinder when the operation of the boom cylinder is suddenly stopped due to an operator's sudden manipulation of an operation lever for a working device. The apparatus includes first and second hydraulic pumps; a boom cylinder; a main control valve; an operation lever for supplying pilot signal pressure to a spool of the main control valve when an operator manipulates the operation lever; operation lever detection means for detecting boom up and boom down signal pressures according to an amount of manipulation of the operation lever; boom cylinder pressure detection means for detecting pressures generated in a large chamber and a small chamber of the boom cylinder; a controller for calculating and outputting a control signal of the main control valve if the boom cylinder has been suddenly stopped; and boom vibration preventing means for controlling the pilot signal pressure being supplied from the second hydraulic pump to the main control valve.

Claims9

Dependent claims

An apparatus for easing an impact on a boom of an excavator, comprising:

first and second hydraulic pumps;
a boom cylinder connected to the first hydraulic pump;
a main control valve, installed in a flow path between the first hydraulic pump and the boom cylinder, for being switched when pilot signal pressure is supplied from an outside, and controlling startup, stop, and turnabout of the boom cylinder;
an operation lever for supplying the pilot signal pressure from the second hydraulic pump to a spool of the main control valve when an operator manipulates the operation lever;
operation lever detection means for detecting boom up and boom down signal pressures according to an amount of manipulation of the operation lever;
boom cylinder pressure detection means for detecting pressures generated in a large chamber and a small chamber of the boom cylinder;
a controller for receiving an input of detected signals from the boom cylinder pressure detection means and the operation lever detection means, and if it is judged that the boom cylinder has been suddenly stopped in accordance with the input signals, calculating and outputting a control signal of the boom cylinder;
and
boom vibration preventing means, installed in a pilot flow path between the second hydraulic pump and the operation lever, for being switchable in accordance with the signals inputted from the controller, and controlling the pilot signal pressure being supplied from the second hydraulic pump to the boom up spool of the main control valve.

6 more elements

A method of controlling an apparatus for easing an impact on a boom of an excavator, including a boom cylinder connected to a hydraulic pump, a main control valve for controlling hydraulic fluid being supplied to the boom cylinder, an operation lever for generating an operation signal for driving the boom cylinder, operation lever detection means for detecting boom up and boom down signal pressures according to an amount of manipulation of the operation lever, boom cylinder pressure detection means for detecting pressures generated in a large chamber and a small chamber of the boom cylinder, a controller for receiving an input of detected signals from the boom cylinder pressure detection means and the operation lever detection means, and electro proportional pressure reducing valves for controlling the pilot signal pressure being supplied to the main control valve, the method comprising:

receiving an input of the boom up and boom down signal pressures from the operation lever detection means and the operating pressures of the boom cylinder from the boom cylinder pressure detection means;
obtaining a reduction rate of manipulation of the operation lever for a predetermined time in accordance with the received input of the boom up and boom down signal pressures, and judging that the operation lever has been suddenly stopped if the obtained value of the reduction rate is smaller than a predetermined value;
receiving the pressure value of the compression chamber of the boom cylinder when the boom is stopped, comparing the received pressure value with a predetermined value, and predicting a boom vibration if the received pressure value is larger than the predetermined value;
calculating and outputting a control value of the electro proportional pressure reducing valve so as to drive a spool of the main control valve of the operation lever if the boom vibration is predicted due to the sudden stop of the operation lever;
and
predicting an end of the boom vibration by checking a difference in pressure between the compression chamber and the expansion chamber of the boom cylinder when the boom is stopped, and controlling the output of the electro proportional pressure reducing valve to be stopped.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/977,650Filed 25 Oct 2007
Priority: KR 10-2006-013615628 Dec 2006
Published: 3 Jul 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

E02F 9/2207
Arrangements for controlling the attitude of actuators, e.g. speed, floating function: for reducing or compensating oscillations
E02F 9/2285
Hydraulic circuits: pilot-operated systems
E02F 9/2292
Hydraulic circuits: systems with two or more pumps
F15B 21/008
Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass:…