CONTROLLABLE COOLANT PUMP HAVING A FLUIDIC ACTUATOR

1 to 9 . (canceled)

10 . A controllable coolant pump for a cooling circuit of an internal combustion engine, comprising:

a pump housing having an inner bore;

a shaft in the inner bore drivable by a drive wheel and rotatably supported by a first bearing and a second bearing, the shaft being at least partially designed as a hollow shaft and having a longitudinal axis;

a rotor fastened to the one end of the shaft and having vanes projecting into a suction chamber and an idler pulley, rotation of the rotor permitting water to be sucked water into the suction chamber via an intake connection of the pump housing and to be delivered to an annular channel of the pump housing via the vanes, the idler pulley being axially movable via a push rod connected to an actuator;

the actuator forming a fluidic actuator having a first fluid pressure chamber and a second fluid pressure chamber.

11 . The controllable coolant pump as recited in claim 10 further comprising an annular first seal, an annular second seal located at an axial distance therefrom and a movable sealing ring situated between the first seal and the second seal, and provided in the inner bore, the first pressure chamber being provided between the first seal and the sealing ring, and the second pressure chamber being provided between the sealing ring and the second seal.

12 . The controllable coolant pump as recited in claim 11 wherein the push rod is situated in the shaft and has a transmission element contacting the sealing ring through at least one opening provided in the shaft.

13 . The controllable coolant pump as recited in claim 10 wherein the push rod has a push rod shoulder on a first end situated within the shaft, and a first shaft shoulder is provided within the shaft, through which the push rod protrudes, an annular, variable first pressure chamber being provided between the push rod shoulder, the first shaft shoulder, the push rod and the shaft.

14 . The controllable coolant pump as recited in claim 10 further comprising an actuator housing having a recess and a cover to at least partially accommodate the push rod in the recess, the actuator housing being situated on the side of the drive wheel facing away from the pump housing, the first pressure chamber being provided in the actuator housing with the aid of the push rod and the second pressure chamber being provided with the aid of the push rod and the cover.

15 . The controllable coolant pump as recited in claim 10 further comprising at least one first end stop for limiting the axial movement of the push rod provided on the shaft or the actuator housing.

16 . The controllable coolant pump as recited in claim 10 wherein the pump housing, the actuator housing or the hollow shaft have at least one fluid-permeable first bore to the first pressure chamber and a second bore to the second pressure chamber for supplying and/or discharging the fluid.

17 . The controllable coolant pump as recited in claim 10 further comprising a spring for actuating the push rod, the spring being situated between the push rod and the shaft or the actuator housing or the cover.

18 . The controllable coolant pump as recited in claim 10 further comprising a sensor element for detecting a position of the push rod.