Fuel pump

Abstract

There is provided a fuel pump ( 10 ) which includes an impeller ( 20 ) in a disk-like shape; a casing ( 18 ) comprised of a pump cover ( 14 ) and a pump body ( 16 ) that rotatably accommodate the impeller; and a motor section ( 70 ) that drives to rotate the impeller; wherein, on at least one of seal portions of the casing ( 18 ) and in its place facing to a series of recesses ( 20 b, 20 c ) of the impeller, a recessed shape ( 35,36 ) in a micron order is formed in expectation of a swelling amount of the series of recesses ( 20 b, 20 c ) of the impeller ( 20 ).

1 . A fuel pump ( 10 ) which includes an impeller ( 20 ) in a disc-like shape; a casing ( 18 ) comprising a pump cover ( 14 ) and a pump body ( 16 ) that rotatably accommodate the impeller; and a motor section ( 70 ) that drives to rotate the impeller,
 wherein, on each of front and back faces of the impeller ( 20 ), a series of recesses ( 20   b , 20   c ) being repeated in a circumferential direction is formed in a region that extends along the circumferential direction with a given distance apart inside from an outer periphery,   wherein, on the pump cover ( 14 ) facing to the front face of the impeller, a first groove ( 31 ) is formed that extends in a region facing to the series of recesses ( 20   c ) of the impeller, from an upstream end ( 31   a ) to a downstream end ( 31   b ),   wherein, on the pump body ( 16 ) facing to the back face of the impeller, a second groove ( 30 ) is formed that extends in a region facing to the other series of recesses ( 20   b ) of the impeller, from an upstream end ( 30   a ) to a downstream end ( 30   b ),   wherein, in the casing ( 18 ), there are formed a fuel discharge opening ( 41 ) that communicates between near the downstream end ( 31   b ) of the first groove ( 31 ) and an outside of the casing ( 18 ), and a fuel suction opening ( 40 ) that communicates between near the upstream end ( 30   a ) of the second groove ( 30 ) and an outside of the casing ( 18 ), and   wherein, seal portions are provided, as viewed in a rotating direction of the impeller, between the upstream end and the downstream end of the first groove ( 31 ) on the pump cover ( 14 ) and between the upstream end and the downstream end of the pump body ( 16 ), respectively,   said fuel pump characterized in that, on at least one of the seal portions of the casing ( 18 ) and in its place facing to the series of recesses ( 20   b , 20   c ) of the impeller, a recessed shape ( 35 , 36 ) in a micron order is formed in expectation of a swelling amount of said series of recesses ( 20   b , 20   c ) of the impeller ( 20 ).   
     
     
         2 . The fuel pump of  claim 1 , characterized in that, on each of the pump cover ( 14 ) and the pump body ( 16 ), the recessed shape ( 35 , 36 ) is formed. 
     
     
         3 . The fuel pump of  claim 1 , characterized in that the series of recesses ( 20   b , 20   c ) of the impeller ( 20 ) is shaped in a recessed shape ( 50   a , 50   b ) in expectation of the swelling amount thereof. 
     
     
         4 . A fuel pump ( 10 ) which includes an impeller ( 20 ) in a disc-like shape; a casing ( 18 ) comprising a pump cover ( 14 ) and a pump body ( 16 ) that rotatably accommodate the impeller; and a motor section ( 70 ) that drives to rotate the impeller,
 wherein, on each of front and back faces of the impeller ( 20 ), a series of recesses ( 20   b , 20   c ) being repeated in a circumferential direction is formed in a region that extends along the circumferential direction with a given distance apart inside from an outer periphery,   wherein, on the pump cover ( 14 ) facing to the front face of the impeller, a first groove ( 31 ) is formed that extends in a region facing to the series of recesses ( 20   c ) of the impeller, from an upstream end ( 31   a ) to a downstream end ( 31   b ),   wherein, on the pump body ( 16 ) facing to the back face of the impeller, a second groove ( 30 ) is formed that extends in a region facing to the other series of recesses ( 20   b ) of the impeller, from an upstream end ( 30   a ) to a downstream end ( 30   b ),   wherein, in the casing ( 18 ), there are formed a fuel discharge opening ( 41 ) that communicates between near the downstream end ( 31   b ) of the first groove ( 31 ) and an outside of the casing ( 18 ), and a fuel suction opening ( 40 ) that communicates between near the upstream end ( 30   a ) of the second groove ( 30 ) and an outside of the casing ( 18 ), and   wherein, seal portions are provided, as viewed in a rotating direction of the impeller, between the upstream end and the downstream end of the first groove ( 31 ) on the pump cover ( 14 ) and between the upstream end and the downstream end of the pump body ( 16 ), respectively,   said fuel pump characterized in that the series of recesses ( 20   b , 20   c ) of the impeller ( 20 ) is shaped in a recessed shape ( 50   a , 50   b ) in expectation of a swelling amount thereof.