Patent ID: 7797935
Filing Date: 2010-09-21
Classification: B60K,B60L,B60P,B60W,B60Y,B65F,F02D,F16H,Y02T,Y02W

Abstract:
1. A hydraulic drive system for a dump truck having a truck frame and a truck body arranged pivotably in an up-and-down direction relative to said truck frame, said hydraulic drive system being to be mounted on said dump truck and being provided with an engine, a generator for outputting electricity corresponding to a rotation speed of said engine, an electric motor drivable responsive to said electricity from said generator, a hydraulic pump drivable by said electric motor, and truck-body elevating cylinders capable of being actuated by pressure oil delivered from said hydraulic pump to pivot said truck body in said up-and-down direction, comprising: a stroke detector for detecting a stroke of the control apparatus of said truck-body elevating cylinders; and a controller for controlling a rotation speed of said engine, said controller comprising a motor electric-power computing means for determining electric power for said electric motor, which corresponds to said stroke detected by said stroke detector, and a discrimination means for discriminating whether or not said electricity from said generator has become greater than said electric power for the electric motor as determined by said motor electric-power computing means.