PURPOSE: To reduce the frequency of cavitation attending upon high speed rotation by specifying a forming position of a circular inlet port formed so as to be interconnected to an expansion areal space, especially a position of a circumferential opening end at the maximum volumetic space side.
CONSTITUTION: An external gear 17 with external teeth 16 one tooth less than the internal teeth 14 is housed in an internal gear 15 free of rotation, interconnecting them to an expansion areal space 20 and a contraction areal space 21 at both circumferential ends of a maximum volumetric space 19 between both these gears 15 and 17, and a circular inlet port 22 and a discharge port 24 are formed there. In this case, the inlet port 22 passes through a turning center point of both gears 15, 17 when a position of a circumferential opening end 22A at the side of the maximum volumetric space 19 is set to (e) of eccentricity of both gears 15, 17, and is set a position separated as far as 1.7e from 0.9e in the gear half-turn direction from a straight line extending toward a position being opposed to a position where both gears 15, 17 are engaged in the deepest with each other. In addition, a central part of this opening end 22A is concavely installed so as not to be opened to the maximum volumetric space 19.
| JP5364798 | Gear type pump |
| JP3015914 | [Title of Invention] Variable output type oil pump |
| JP3642422 | OIL PUMP |
SAKAMOTO MASAMI
ISHIKAWA KATSUNORI
| JPS5982594A | 1984-05-12 |