A variable capacity fluid pump for an engine

A variable capacity fluid pump that can be controlled independently of the rotation of the engine is provided. The fluid pump comprises a planetary gear mechanism 12 having a first gear 20, second gears 22 and a third gear 18. The second gears are connected to a crankshaft of the engine and transmits a rotational force of the crankshaft. The third gear is connected to the fluid pump. The fluid pump further comprises braking means 14 connected to the first gear. The breaking means generates a braking force upon the first gear. The fluid pump further comprises a one-way clutch 16 provided between the second gears and the third gear. The braking means controls a rotational speed of the first gear so that a rotational speed of the fluid pump is controlled independently of a rotational speed of the crankshaft of the engine.