Fuel pump

Claim 2

A fuel pump comprising impeller means having a plurality of vanes at an outer circumference thereof and a wall member surrounding said vanes and formed with fuel groove means to define a pump chamber, said fuel groove means comprises an outer circumference, an inner circumference, an intake portion and a discharge portion, wherein a portion of an edge of said inner circumference of said fuel groove intersecting said vanes at said discharge portion is chamfered in order to reduce shearing noise generated when the impeller vanes move across said intersecting groove edge portion.

Claim 3

The fuel pump as defined in claim 1 wherein the discharge portion of said fuel groove means is diverted outwardly of the outer circumference of said vanes of said impeller.

Claim 4

The fuel pump as defined in claim 1 wherein the discharge portion of said fuel groove means is diverted inwardly of the outer circumference of said vanes of said impeller.

Claim 5

The fuel pump as defined in claim 1, wherein said impeller means comprises a first and second impellers arranged in opposed relationship to each other; and said wall member comprises an inlet member, an outlet member, a first annular spacer located around an outer circumference of said first impeller, an intermediate plate located between said first and second impellers, and a second annular spacer located around an outer circumference of said second impeller; and said fuel groove means comprises a first groove formed on said inlet member at a position opposed to said vanes of said first impeller, a second groove formed on said intermediate plate at a position opposed to said vanes of said first impeller, a third groove formed on said intermediate plate at a position opposed to said vanes of said second impeller, and a fourth groove formed on said outlet member at a position opposed to said vanes of said second impeller.

Claim 6

The fuel pump as defined in claim 4, wherein the intersecting edges of said first and second grooves intersecting said vanes of said first impeller are chamfered.

Claim 7

The fuel pump as defined in claim 5, wherein downstream end portions of said first and second grooves are formed along the outer circumference of said vanes of said first impeller.

Claim 8

The fuel pump as defined in claim 5, wherein downstream end portions of said first and second grooves are diverted radially outwardly.

Claim 9

The fuel pump as defined in claim 5, wherein downstream end portion of said first and second grooves are curved toward a center of said inlet member.

Claim 10

The fuel pump as defined in claim 4, wherein the intersecting edges of said first and second grooves intersecting said vanes of said first impeller are chamfered, and the intersecting edges of said third and fourth grooves intersecting said vanes of said second impeller are also chamfered.

Claim 11

The fuel pump as defined in claim 1, wherein a chamfered surface of said intersecting edges is configured into a sectionally arcuate shape.

Claim 12

The fuel pump as defined in claim 10, wherein a width of said chamfered surface is in the range of 1.0-2.0 mm and a chamfering angle of said chamfered surface is about 30 degrees.

Claim 13

The fuel pump as defined in claim 1, wherein a chamfered surface of said intersecting edge is configured into a sectionally straight shape.

Claim 14

The fuel pump as defined in claim 12, wherein a width of said chamfered surface is in the range of 1.0-2.0 mm and a chamfering angle of said chamfered surface is about 30 degrees.