Patent ID: 9541103
Date: 2017-01-10
CPC Classifications: B60K,E02F,F02D,F15B,Y02T

Claim:
1. A power source apparatus for a hydraulic actuator, comprising: a hydraulic pump which drives the hydraulic actuator; a generator-motor capable of operating as an electric generator and an electric motor; an engine to which the hydraulic pump and the generator-motor are connected; an electric storage device which is charged by operation of the generator-motor as an electric generator, and which is capable of supplying charged electric power to the generator-motor in order to cause the generator-motor to operate as an electric motor so as to assist driving of the hydraulic pump; a pump pressure detector which detects a discharge pressure of the hydraulic pump as a load pressure of the hydraulic pump; and a controller which implements horsepower control for determining a flow rate for the hydraulic pump on the basis of flow rate-pressure characteristics that define a maximum input setting for the hydraulic pump by the discharge pressure of the hydraulic pump and the flow rate of the hydraulic pump, and the discharge pressure detected by the pump pressure detector, wherein the flow rate-pressure characteristics are set in such a manner that the maximum input setting for the hydraulic pump is greater than the maximum output of the engine by a predetermined flow-rate difference when the discharge pressure is at a predetermined reference pressure, wherein the predetermined flow-rate difference gradually becomes smaller as the discharge pressure changes from the reference pressure towards higher pressure, and wherein the maximum input setting for the hydraulic pump becomes smaller than the maximum output of the engine when the discharge pressure is at maximum pressure.