Patent ID: 7588118
Filing Date: 2009-09-15
Classification: E02F,F02D

Abstract:
1. A work machine comprising: hydraulic actuators activated by pressure oil from a hydraulic pump driven by an engine; an implement driven by activation of the hydraulic actuators; an engine control device for controlling output of the engine in accordance with each of a plurality of operation modes which are set according to contents of operations, the plurality of operation modes including a finely-controlled operation mode in which the implement is allowed to operate at ultraslow speed, and a revolution speed operation mode in which a revolution speed for the engine is set to a value in a vicinity of a rated output revolution speed; and operation mode selecting means for selecting any one of the plurality of operation modes, wherein the engine control device is arranged such that when the finely-controlled operation mode has been selected from the plurality of operation modes by the operation mode selecting means, the engine control device performs isochronous control for maintaining the revolution speed of the engine at a substantially constant value irrespective of load fluctuations, and wherein the engine control device is arranged such that when the revolution speed operation mode has been selected from the plurality of operation modes by the operation mode selecting means, the engine control device performs regulation control for increasing or decreasing the revolution speed of the engine according to load fluctuations.