PURPOSE: To enhance efficiency of a pump by setting an area of an inlet portion in a suitable range of a channel connected to an inlet hole in the most upstream larger than that of a channel in the downstream of the inlet portion in such a manner as to gradually become smaller toward the downstream.
CONSTITUTION: When the first and second impellers 11, 12 of a pump 10 are rotated by the drive of a motor 2, fuel flows into a casing 1 through an inlet hole 25, a first channel 15, a communication hole, a second channel 16 and an outlet hole 30 via a fuel filter 31 so as to be discharged outside from a discharge port 32. There is provided an inlet portion 15a where a channel area gradually becomes larger toward the inlet hole 25 with the variation of a depth of channel grooves 23, 24. A connecting portion 33 of a pump body 17 to the channel groove 23 is formed in a gently curved surface. Therefore, the fuel flowing from the inlet hole 25 into the channel 15 is gradually increased in its pressure without any sharp change in the inlet portion 15a so as to be introduced to the channel on the downstream, thus restraining any generation of cavitation.
KIKUTA HIKARI
TAKEUCHI HITOSHI
