VARIABLE CAPACITY OIL PUMP

PROBLEM TO BE SOLVED: To manufacture a variable capacity oil pump that can have a shaft eccentric mechanism of an outer rotor and improve efficiency of the pump.SOLUTION: A variable capacity oil pump including an outer rotor 4 having a predetermined eccentric amount e to the rotational center of an inner rotor 3, a guiding means B that oscillates the outer rotor 4 while keeping the eccentric amount e to the inner rotor 3 and along a predetermined locus, and a pump housing A having a second seal land 15 formed among a suction port 12, a discharge port 13, a trailer 13b of the discharge port 13, and a leader 12a of the suction port 12, wherein an engaging region Sb of the inner rotor 3 and outer rotor 4 is configured such that the engaging region should be always overlapped upon at least a portion of the second seal land 15 by a swinging operation of the guiding means B over an initial position through a final position of the outer rotor 4, is provided.