Fuel pump

Abstract

In a fuel pump, an impeller is rotatably accommodated between a suction side cover and a pump casing. A pump channel of the suction side cover is positioned on an axial side opposite to a fuel discharge port with respect to the impeller. The impeller has blade grooves circumferentially outside and communicating holes circumferentially inside. A wall of a terminal end portion of the pump channel of the suction side cover has a guide portion directing from the blade grooves toward the communicating holes. The terminal end portion is pointed in shape in a rotation direction of the impeller. Fuel pressurized in the pump channel is guided from the blade grooves to the communicating holes at the terminal end portion without steeply reducing flow speed and flows through the communicating holes to the fuel discharge port.

1 . A fuel pump comprising: 
 a rotary member having a plurality of blade grooves and a plurality of communicating holes, the blade grooves being formed on one and another axial end faces of the rotary member at given intervals in a rotation direction of the rotary member, respectively, and the communicating holes being arranged at a circumferential position shifted in a radial direction from the blade grooves at given intervals in the rotation direction and formed so as to pass through the rotary member from the one axial end face thereof to the another axial end face thereof; and    a case member rotatably accommodating the rotary member therein and having a fuel suction port, a fuel discharge port and a pump channel, the pump channel being provided with a start end portion communicating with the fuel suction port and with a terminal end portion communicating with the fuel discharge port and extending from the start end portion to the terminal end portion along the blade grooves in the rotation direction of the rotary member so that fuel is sucked from the fuel suction port, pressurized in the pump channel and discharged from the discharge port by a rotation of the rotary member,    wherein the fuel discharge port is formed on a side of the one axial end face of the rotary member, and    a channel wall forming the terminal end portion of the pump channel on a side of the another axial end face of the rotary member has a guide portion for guiding the fuel from a circumferential position facing the blade grooves toward a circumferential position facing the communicating holes.    
     
     
         2 . The fuel pump according to  claim 1 , wherein, the blade grooves are formed in a vicinity of an outer  5  circumference of the rotary member, 
 the communicating holes are formed at a circumferential position radially inside the blade grooves, and  
 the guide portion guides the fuel to flow radially inward from the circumferential position facing the blade grooves into the circumferential position facing the communicating holes.  
 
     
     
         3 . The fuel pump according to  claim 1 , wherein, 
 the communicating holes are formed in a vicinity of an outer circumference of the rotary member,    the blade grooves are formed at a circumferential position radially inside the communicating holes, and    the guide portion guides the fuel to flow radially outward from the circumferential position facing the blade grooves into the circumferential position facing the communicating holes.    
     
     
         4 . The fuel pump according to  claim 1 , wherein at least a part of the guide portion includes a channel wall side face directed gradually and smoothly from the circumferential position facing the blade grooves toward the circumferential position facing the communicating holes.  
     
     
         5 . The fuel pump according to  claim 4 , wherein the channel wall side face is formed in an arc shape.  
     
     
         6 . The fuel pump according to  claim 1 , wherein a cross sectional area of the terminal end portion of the pump channel on a side of the another axial end face of the rotary member is gradually smaller toward a tip end of the terminal end portion thereof in the rotation direction of the rotary member.  
     
     
         7 . A fuel pump comprising: 
 a rotary member having a plurality of blade grooves and a plurality of communicating holes, the blade grooves being formed on one and another axial end faces of the rotary member at given intervals in a rotation direction of the rotary member, respectively, and the communicating holes being arranged at a circumferential position shifted in a radial direction from the blade grooves at given intervals in the rotation direction and formed so as to pass through the rotary member from the one axial end face thereof to the another axial end face thereof; and    a case member rotatably accommodating the rotary member therein and having a fuel suction port, a fuel discharge port and a pump channel, the pump channel being provided with a start end portion communicating with the fuel suction port and with a terminal end portion communicating with the fuel discharge port and extending from the start end portion to the terminal end portion along the blade grooves in the rotation direction of the rotary member so that fuel is sucked from the fuel suction port, pressurized in the pump channel and discharged from the discharge port by a rotation of the rotary member.    wherein the fuel discharge port is formed on a side of the one axial end face of the rotary member, and    a cross sectional area of the terminal end portion of the pump channel on a side of the another axial end face of the rotary member is smaller toward a tip end of the terminal end portion thereof in the rotation direction of the rotary member,    
     
     
         8 . The fuel pump according to  claim 7 , wherein, 
 the blade grooves are formed in a vicinity of an outer circumference of the rotary member, and    the communicating holes are formed at a circumferential position radially inside the blade grooves.    
     
     
         9 . The fuel pump according to  claim 7 , wherein, 
 the communicating holes are formed in a vicinity of an outer circumference of the rotary member, and    the blade grooves are formed at a circumferential position radially inside the communicating holes.    
     
     
         10 . The fuel pump according to  claim 7 , wherein each of the pump channels on both sides of the one and another axial end faces is widened at the start end portion and the terminal end portion in the direction in which the communicating holes are shifted from the blade grooves so that each of the start and terminal end portions faces both of the blade grooves and the communicating holes.  
     
     
         11 . The fuel pump according to  claim 1 , wherein, 
 the pump channel on a side of the one axial end face of the rotary member is widened at the start end portion and the terminal end portion in the direction in which the communicating holes are shifted from the blade grooves so that each of the start and terminal end portions on a side of the one axial end face of the rotary member faces both of the blade grooves and the communicating holes, and    the pump channel on a side of the another axial end face of the rotary member is widened at the start end portion in the direction in which the communicating holes are shifted from the blade grooves so that the start end portion on a side of the another axial end face of the rotary member faces both of the blade grooves and the communicating holes.    
     
     
         12 . The fuel pump according to  claim 10 , wherein the fuel suction port is formed on a side of the another axial end face of the rotary member.  
     
     
         13 . The fuel pump according to  claim 1 , wherein, at each of the one and another axial end faces of the rotary member, the communicating holes are formed in correspondence with the blade grooves.  
     
     
         14 . The fuel pump according to  claim 1 , wherein, at each of the one and another axial end faces of the rotary member, the communicating holes are formed near the blade grooves with a partition wall therebetween.  
     
     
         15 . The fuel pump according to  claim 1 , wherein, at each of the one and another axial end faces of the rotary member, the communicating holes and the blade grooves are equal in number, and at least one of the one and another axial end faces has communication passages through which the blade grooves communicate with the communicating holes.  
     
     
         16 . The fuel pump according to  claim 1 , wherein at least one of the one and another axial end faces of the rotary member has communication passages through which the blade grooves communicate with the communicating holes.  
     
     
         17 . The fuel pump according to  claim 1 , wherein the blade grooves formed on the one axial end face and the blade grooves formed on the another axial end face are shifted in the rotation direction of the rotary member.  
     
     
         18 . The fuel pump according to  claim 1 , wherein the rotary member has an annular portion continuously surrounding an outer circumference of each of the blade grooves.  
     
     
         19 . The fuel pump according to  claim 7 , wherein the rotary member has an annular portion continuously surrounding an outer circumference of each of the blade grooves.  
     
     
         20 . fuel pump according to  claim 18 , wherein the pump channels formed on both sides of the one and another axial end faces of the rotary member are independent from each other and in communication with the blade grooves formed on the one and another axial end faces of the rotary member, respectively.  
     
     
         21 . fuel pump according to  claim 1 , wherein the blade grooves formed on the one axial end face of the rotary member are separated from the blade grooves formed on the another axial end face thereof to prevent fuel from flowing directly therebetween.