Patent ID: 6935839

Claim:
A variable capacity coolant pump comprising: a pump housing for directing the flow of fluid through said pump between an inlet and an outlet; a shaft rotatably journaled to said pump housing; an impeller coupled to said pump housing for pumping fluid through said pump housing from said inlet to said outlet, said impeller rotatably journaled to said shaft and including an upper shroud and a lower shroud spaced below and generally parallel to said upper shroud and at least one vane pivotally coupled between said upper and lower shrouds for pivotal movement between a plurality of pitch angles relative to said shaft; a pitch plate fixedly secured to said shaft for rotation therewith and operatively coupled to said vane for pivoting said vane relative to said upper and lower shroud and controlling said pitch angle of said vane; and a spring coupled to said pitch plate for biasing said vane to a maximum pitch angle, wherein said vane varies in said pitch in response to a force of fluid pressure from said inlet and automatically reduces said pitch angle of said vane upon an increase in said fluid pressure from said inlet to reduce the flow of fluid to said outlet.