OIL PUMP ROTOR

Provided is an oil pump rotor capable of improving a volume efficiency and a quietness. When a diameter of a base circle bi of an inner rotor is Φ bi; a diameter of a first outer rolling circle Di is Φ Di; a diameter of a first inner rolling circle di is Φ di; a diameter of a base circle bo of an outer rotor is Φ bo; a diameter of a second outer rolling circle Do is Φ Do; a diameter of a second inner rolling circle do is Φ do; and an eccentricity amount between the inner rotor and the outer rotor is e, Φ bi=n·(Φ Di+Φ di) and Φ bo=(n+1)·(Φ Do+Φ do) hold; either Φ Di+Φ di=2e or Φ Do+Φ do=2e holds; and Φ Do>Φ Di and Φ di>Φ do hold. When a clearance between the inner rotor and the outer rotor is t, 0.3 ((Φ Do+Φ do)−(Φ Di+Φ di))·(n+1)/t 0.6 holds, provided that Φ Di+Φ di=2e; or 0.3 ((Φ Do+Φ do)−(Φ Di+Φ di))·n/t 0.6 holds, provided that Φ Do+Φ do=2e.