Patent ID: 7231765

Claim:
A pump unit configured to be capable of transmitting a rotational power from a driving power source which is operatively connected thereto to an actuator through a pair of hydraulic fluid lines, the pump unit comprising: an input shaft which is operatively connected to the driving power source; a hydraulic pump main body which is operatively driven by the input shaft and is fluidly connected to the actuator through the pair of hydraulic fluid lines; a PTO shaft which is operatively driven by the input shaft; a PTO clutch mechanism which is inserted in a transmission path from the input shaft to the PTO shaft; an auxiliary pump main body; a suction line which has a first end fluidly connected to a fluid reservoir and a second end fluidly connected to a suction port of the auxiliary pump main body; a discharge line which is fluidly connected to the discharge port of the auxiliary pump main body; a charge line which supplies a part of hydraulic fluid from the discharge line to the pair of hydraulic fluid lines through check valves; a PTO hydraulic fluid line which supplies a part of hydraulic fluid from the discharge line to the PTO clutch mechanism through a PTO relief valve; a pressure-reducing valve which has a primary side fluidly connected to the discharge line; and a resistance valve which is fluidly connected to the primary side of the pressure-reducing valve, wherein the PTO hydraulic fluid line and the charge line are fluidly connected to the primary side and a secondary side of the pressure-reducing valve, respectively.