Patent ID: 8438843

Claim:
A hydraulic system of a work machine with a hydraulically controlled implement, the hydraulic system comprising: an operating oil flow passage configured to flow operating oil supplied from a main pump; a boost flow oil passage configured to supply operating oil from a sub-pump to the operating oil flow passage, the sub-pump being different from the main pump and being connected to the operating oil flow passage at a confluence; a connection unit provided downstream of the confluence on the operating oil flow passage, wherein the connection unit is configured to connect to either one of a high-flow actuator for the implement requiring an amount increase of the operating oil and a normal actuator for the implement not requiring an amount increase of the operating oil; a high-flow valve which is provided on the boost flow oil passage and configured to adjust the amount increase; a controller configured to control the high-flow valve; an annunciation device connected to the controller; a high-flow switch which is connected to the controller and configured to effect or cancel a command of the amount increase on the high-flow valve; an annunciation control unit which is provided in the controller and configured to make annunciation through the annunciation device when the connection unit is connected to the normal actuator and the amount increase is effected by the high-flow valve in accordance with an operation of the high-flow switch; and a discrimination device configured to output a discriminative signal for discriminating whether the actuator connected to the connection unit is the high-flow actuator or the normal actuator, the discrimination device outputting the discriminative signal to the controller when the actuator is connected to the connection unit, the controller making annunciation through the annunciation device when the discriminative signal indicates that the normal actuator is connected, wherein the connection unit comprises a high-flow connection part for connecting the high-flow actuator, and a normal connection part for connecting the normal actuator, the operating oil flow passage bifurcates on a downstream side at a branching point into a first art and a second part, the first part includes a first connection part that serves as a component of the high-flow connection part, and the second part includes a second connection part that serves as a component of the normal connection part, and the confluence is provided between the first connection part and the branching point, and a check valve is disposed between the confluence and the branching point.