Patent ID: 8301346

Claim:
A traveling system for construction equipment, comprising: a variable-displacement hydraulic pump and a pilot pump connected to an engine; a variable-displacement traveling motor connected to the hydraulic pump; a traveling speed selection switch selecting any one of a low-speed traveling and a high-speed traveling of the construction equipment; a solenoid valve installed in a flow path between the pilot pump and the traveling motor to be shifted to control an inclination angle of a swash plate of the traveling motor in accordance with a signal inputted from the traveling speed selection switch; a traveling spool installed in a flow path between the hydraulic pump and the traveling motor to be shifted to control a start, a stop, and a direction change of the traveling motor; a traveling manipulator installed in a flow path between the pilot pump and the traveling spool to control signal pressure being applied to shift the traveling spool; a manipulation amount sensor sensing a manipulation amount of the traveling manipulator and outputting a detection signal; an electro-proportional control valve variably controlling a discharge flow rate of the hydraulic pump by controlling an inclination angle of a swash plate of the hydraulic pump in proportion to an electric signal inputted from an outside; and a controller outputting the electric signal to the electro-proportional control valve; wherein, if the controller senses that the high-speed traveling is selected by the traveling speed selection switch and the traveling is manipulated by the traveling manipulator, the inclination angle of the swash plate of the hydraulic pump is variably controlled to be in proportion to the electric signal outputted from the controller, so that the discharge flow rate of the hydraulic pump exceeds a predetermined flow rate in comparison to the low-speed traveling wherein, if the high-speed traveling of the traveling device is selected by the traveling speed selection switch, and the discharge flow rate of the hydraulic pump set on the basis of the low-speed traveling is controlled, the discharge flow rate of the hydraulic pump is variably controlled in a manner that the discharge flow rate of the hydraulic pump becomes higher than a minimum flow rate Qmin by the predetermined flow rate Qa up to a manipulation amount Pi-min the discharge flow rate of the hydraulic pump starts to increase, and the discharge flow rate of the hydraulic pump becomes maximum Qmax at a manipulation amount Pi-max the discharge flow rate of the hydraulic pump becomes maximum.