Patent ID: 8249765

Claim:
A drive system for an electrically driven dump truck comprising: a prime mover; an electronic governor for controlling the revolution speed and torque of the prime mover; an alternating-current generator driven by the prime mover; a hydraulic pump for working driven by the prime mover; at least two electric motors for traveling, each of which is driven by the electric power supplied by the alternating-current generator; and at least two inverters, each of which is connected to the alternating-current generator, and each of which controls each of the electric motors, wherein the drive system comprises: an accelerator pedal; a shift lever that is operated at one of a plurality of positions including a neutral position and a forward position; motor control means for controlling the inverters to control the electric motors in response to an operation amount (p) of the accelerator pedal; prime mover control means for, when the shift lever is located at the neutral position, calculating a target revolution speed corresponding to the operation amount of the accelerator pedal on the basis of first target revolution speed characteristics which are suitable for driving of the hydraulic pump for working to control the electronic governor on the basis of the target revolution, and for, when the shift lever is located at the forward position, calculating a target revolution speed corresponding to the operation amount of the accelerator pedal on the basis of second target revolution speed characteristics which are suitable for driving of the electric motors to control the electronic governor on the basis of the target revolution speed, wherein the first target revolution speed characteristics are set so that when the operation amount of the accelerator pedal is at 0, the target revolution speed is the minimum revolution speed, and so that with the increase in the operation amount of the accelerator pedal, the target revolution speed increases from the minimum revolution speed up to the maximum revolution speed; and the second target revolution speed characteristics are set so that when the operation amount of the accelerator pedal is at 0 or a predetermined very small operation amount, the target revolution speed is a medium-speed revolution speed which is higher than the minimum revolution speed and lower than the maximum revolution speed, and so that with the increase in the operation amount of the accelerator pedal, the target revolution speed increases from the medium-speed revolution speed up to a high-speed revolution speed.