Abstract:
Provided is an impeller for a fuel pump of a vehicle capable of decreasing a magnitude of high frequency fluid noise due to high speed rotation of the impeller by upper and lower blades of impeller blades positioned between upper and lower casings of the fuel pump and coupled to a shaft of a driving motor to deliver a fuel by rotational force so as to have asymmetrical angles based on the center of a thickness of an impeller body in sucking the fuel from a fuel tank and supplying the fuel to an engine of an internal combustion engine.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2013-0096456, filed on Aug. 14, 2013, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The following disclosure relates to an impeller for a fuel pump of a vehicle. More particularly, the following disclosure relates to an impeller for a fuel pump of a vehicle capable of decreasing a magnitude of high frequency fluid noise due to high speed rotation of the impeller by improving shapes of impeller blades positioned between upper and lower casings of the fuel pump and coupled to a shaft of a driving motor to deliver a fuel by rotational force in sucking the fuel from a fuel tank and supplying the fuel to an engine of an internal combustion engine. 
       BACKGROUND 
       [0003]    Generally, a fuel pump of a vehicle is mounted in a fuel tank of the vehicle and serves to suck a fuel and forward the fuel to a fuel injection device mounted in an engine. 
         [0004]    In addition, the fuel pump of the vehicle is classified into a mechanical fuel pump and an electrical fuel pump, and a turbine type fuel pump  10 , which is a kind of electrical fuel pump, is mainly used in an engine using gasoline as the fuel. 
         [0005]    The turbine type fuel pump  10  is configured to include a driving motor  20  disposed in a motor housing  60  thereof, upper and lower casings  30  and  40  disposed at a lower end portion of the motor housing  60  and closely adhered to each other, and an impeller  50  disposed between the upper and lower casings  30  and  40 , as shown in  FIG. 1 . In addition, the impeller  50  is coupled to a shaft  21  of the driving motor  20  to thereby be rotated together with the driving motor  20 . 
         [0006]    That is, as the impeller  50  is rotated, a pressure difference is generated, such that a fuel is sucked in the impeller  50 , and pressure of the fuel rises by a rotational flow generated by continuous rotation of the impeller  50 , such that the fuel is discharged. 
         [0007]    Therefore, the fuel is introduced into a fuel inlet  41  of the lower casing  40  and then passes through the rotating impeller  50 , such that pressure of the fuel is raised. Then, the fuel flows to a check valve  70  formed at an upper portion of the motor housing  60  along an inner portion of the motor housing  60  through a fuel outlet  31  of the upper casing  30  and is then supplied to a fuel injection device mounted in an engine of a vehicle. 
         [0008]    Here, the impeller  50  includes several blades  51  formed in a disk shape in an outward direction of a circumferential surface thereof along the circumferential surface thereof and blade chambers  52  formed between the respective blades  51  so as to penetrate through both surfaces of the impeller  50  as shown in  FIG. 2 , and the fuel is introduced into the fuel inlet  41  of the lower casing  40 , such that a rotational flow is generated in a space between the blade chamber  52  and a lower flow passage groove  42  formed in the lower casing  40  and an upper flow passage groove  32  formed in the upper casing  30  and a circulation process in which the fuel is introduced into a blade chamber  52  adjacent to the blade chamber  52  to generate the rotational flow is repeated to convert kinetic energy due to the rotation of the impeller  50  into pressure energy of the fuel, such that the fuel is delivered to the fuel outlet  31  of the upper casing  30 , as shown in  FIG. 3 . 
         [0009]    Further, the impeller  50  according to the prior art includes a circumference center guider  53  formed at the center of the circumferential surface thereof along the circumferential surface thereof, thereby making it possible to efficiently generate the rotational flow formed in a space between the blade chamber  52  and the lower flow passage groove  42  and the rotational flow formed in a space between the blade chamber  52  and the upper flow passage groove  32 . 
         [0010]    However, the fuel introduced into the fuel inlet  41  flows along the lower flow passage groove  42  of the lower casing  40  and then flows the upper flow passage groove  32  of the upper casing  30  through the blade chamber  52  at an end of the lower flow passage groove  42 . In this case, impact of a fluid is generated in the blade chamber  52  due to the fuel passing through the blade chamber  52 , such that high frequency noise is generated. 
         [0011]    As the prior art related to this, Korean Patent Laid-Open Publication No. 2012-0113332 entitled “Impeller for Fuel Pump of Vehicle” has been disclosed. 
       PRIOR ART DOCUMENT 
     Patent Document 
     KR 2012-0113332 A (2012 Oct. 15) 
     SUMMARY 
       [0012]    An embodiment of the present invention is directed to providing an impeller for a fuel pump of a vehicle capable of decreasing a magnitude of high frequency fluid noise due to high speed rotation of the impeller by forming upper and lower blades of impeller blades positioned between upper and lower casings of the fuel pump and coupled to a shaft of a driving motor to deliver a fuel by rotational force so as to have asymmetrical angles based on the center of a thickness of an impeller body. 
         [0013]    In one general aspect, an impeller  1000  for a fuel pump of a vehicle includes: an impeller body  100  having a disk shape and having a shaft fixing hole  120  at the center thereof so as to penetrate therethrough so that a shaft of a driving motor is inserted thereinto and coupled thereto; and a plurality of blades  200  formed at predetermined intervals along an outer circumferential surface of the impeller body  100  and formed in an outward direction of the circumferential surface, wherein each of the blades  200  includes an upper blade  200   a  formed at an upper side of the impeller body  100  in a thickness direction and a lower blade  200   b  formed at a lower side of the impeller body  100  in the thickness direction, and an angle a of the upper blade  200   a  is larger than an angle b of the lower blade  200   b.    
         [0014]    The angle a of the upper blade  200   a  may be larger than the angle b of the lower blade  200   b  by 3 to 5 degrees. 
         [0015]    A sum of the angle a of the upper blade  200   a  and the angle b of the lower blade  200   b  may be 90 to 100 degrees. 
         [0016]    A height h1 of the upper blade  200   a  may be the same as a height h2 of the lower blade  200   b.    
         [0017]    The impeller for a fuel pump of a vehicle may further include a side ring  300  formed on outer circumferential surfaces of the plurality of blades  200  so as to form blade chambers  210  allowing discharge and introduction of a fuel to be made at upper and lower sides of the blade  200 , respectively. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a cross-sectional view showing a schematic configuration of a fuel pump of a vehicle according to the prior art. 
           [0019]      FIG. 2  is a perspective view showing a structure of an impeller according to the prior art. 
           [0020]      FIG. 3  is a partial cross-sectional view showing an impeller and upper and lower casings according to the prior art. 
           [0021]      FIG. 4  and  FIGS. 5A and 5B  are, respectively, a perspective view and a partially enlarged view showing an impeller for a fuel pump of a vehicle according to the present invention. 
           [0022]      FIGS. 6A and 6B  are front views showing a cross section of an impeller blade according to the present invention. 
           [0023]      FIGS. 7 and 8  are experimental graphs and data showing a comparison result between noise and pump efficiency of an example of an impeller in which an angle of an upper blade is the same as that of a lower blade according to the prior art and noise and pump efficiency of an example of an impeller in which an angle of an upper blade is larger than that of a lower blade according to the present invention. 
       
    
    
       [0024]      
         [0000]    
       
         
               
             
               
             
               
               
             
           
               
                   
               
               
                 [Detailed Description of Main Elements] 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1000: Impeller for fuel pump of vehicle 
               
             
          
           
               
                 100: Impeller body 
                   
               
               
                 110: Circumference center guider 
                 120: Shaft fixing hole 
               
               
                 200: Blade 
               
               
                 200a: Upper blade 
                 200b: Lower blade 
               
               
                 210: Blade chamber 
                 220: Blade center guider 
               
               
                 300: Side ring 
               
               
                 400: Lower flow passage groove 
                 500: Upper flow passage groove 
               
               
                   
               
             
          
         
       
     
       DETAILED DESCRIPTION OF EMBODIMENTS 
       [0025]    Hereinafter, an impeller for a fuel pump of a vehicle according to the present invention as described above will be described in detail with reference to the accompanying drawings. 
         [0026]      FIG. 4  and  FIGS. 5A and 5B  are, respectively, a perspective view and a partially enlarged view showing an impeller for a fuel pump of a vehicle according to the present invention, and  FIGS. 6A and 6B  are front views showing a cross section of an impeller blade according to the present invention. 
         [0027]      FIGS. 4 to 6B , an impeller  1000  for a fuel pump of a vehicle according to the present invention is configured to include an impeller body  100  having a disk shape and having a shaft fixing hole  120  at the center thereof so as to penetrate therethrough so that a shaft of a driving motor is inserted thereinto and coupled thereto; and a plurality of blades  200  formed at predetermined intervals along an outer circumferential surface of the impeller body  100  and formed in an outward direction of the circumferential surface, wherein each of the blades  200  includes an upper blade  200   a  formed at an upper side of the impeller body  100  in a thickness direction and a lower blade  200   b  formed at a lower side of the impeller body  100  in the thickness direction, and an angle a of the upper blade  200   a  is larger than an angle b of the lower blade  200   b.    
         [0028]    The impeller body  100  is formed in the disk shape and has the shaft fixing hole  120  formed at the center thereof. 
         [0029]    In addition, the plurality of blades  200  are formed in the outward direction of the circumferential surface of the impeller body  100  at predetermined intervals along the circumferential surface of the impeller body  100  and have blade chambers  210  formed therebetween. That is, the blade chamber  210  is a space formed between two adjacent blades  200 . 
         [0030]    Here, the blade chamber  210  has a fuel introduced thereinto when the impeller is rotated to generate rotational flows between upper and lower flow passages grooves  500  and  400  each formed in upper and lower casings formed at upper and lower sides of the impeller so as to correspond to positions of the blade chamber  210 , such that pressure of the fuel is raised. 
         [0031]    Here, the respective blades  200  are formed in the thickness direction of the impeller body  100  and has a shape of “&lt;”. Here, each of the blades  200  includes the upper blade  200   a  formed at the upper side of the impeller body  100  in the thickness direction and the lower blade  200   b  formed at the lower side of the impeller body  100  in the thickness direction, and the angle a of the upper blade  200   a  is larger than the angle b of the lower blade  200   b.    
         [0032]    That is, as shown in  FIGS. 6A and 6B , an inclined angle a of the upper blade  200   a  formed at an upper side based on a reference line SL is different from an inclined angle b of the lower blade  200   b  formed at a lower side based on the reference line SL, such that the upper blade  200   a  has a form in which it relatively slightly stands and the lower blade  200   b  has a form in which it relatively slightly lies. 
         [0033]    Therefore, the fuel introduced into a fuel inlet of the lower casing flows along the lower flow passage groove  400  of the lower casing and then flows to the upper flow passage groove  500  of the upper casing through the blade chamber  210  at an end of the lower flow passage groove  400 . Here, impact of a fluid due to the fuel passing through the blade chamber  210  is decreased by the inclined angles of the upper and lower blades  200   a  and  200   b , such that high frequency noise is decreased. 
         [0034]    In addition, flow energy loss of the fluid is decreased due to the decrease in the impact of the fluid, such that pumping efficiency is improved. 
         [0035]    In addition,  FIGS. 7 and 8  are experimental graphs and data showing a comparison result between an example of an impeller in which an angle of an upper blade is the same as that of a lower blade according to the prior art and an example of an impeller in which an angle of an upper blade is larger than that of a lower blade according to the present invention. As shown in  FIGS. 7 and 8 , it may be appreciated that in the impeller according to the present invention, high frequency noise is decreased as compared with an impeller according to the prior art, and pump efficiency is increased as compared with an impeller according to the prior art. 
         [0036]    Here, it is preferable that the angle a of the upper blade  200   a  is larger than the angle b of the lower blade  200   b  by 3 to 5 degrees. 
         [0037]    That is, when a difference between the inclined angles is excessively small, an impact decrease effect of the fluid may be decreased, and when the difference between the inclined angles is excessively large, a flow resistance of the fluid is increased, such that pumping efficiency may be decreased. Therefore, the upper and lower blades need to be formed in a range of a predetermined angle difference. 
         [0038]    In addition, it is preferable that the sum of the angle a of the upper blade  200   a  and the angle b of the lower blade  200   b  is 90 to 100 degrees. 
         [0039]    That is, when the sum c of the angles formed by the upper and lower blades  200   a  and  200   b  based on the reference line SL is excessive small or large, pumping performance and efficiency may be deteriorated. Therefore, the upper and lower blades also need to be formed at an appropriate angle. 
         [0040]    In addition, a height h1 of the upper blade  200   a  may be the same as a height h2 of the lower blade  200   b.    
         [0041]    Since a circumference center guider  110  may be formed in a protrusion form along the center of the circumferential surface in the impeller body  100 , the upper blade  200   a  formed at an upper side based on the circumference center guider  110  formed at the center of a thickness of the impeller body  100  and the lower blade  200   b  formed at a lower side based on the circumference center guider  110  may have the same height as each other. 
         [0042]    In addition, each of the plurality of blades  200  may include a blade center guider  220  formed in a protrusion form at the center thereof in a radial direction on a surface thereof in a direction in which the impeller is rotated, wherein the blade center guider  220  may be connected to the circumference center guider  110 . The fuel introduced into the blade chamber  210  more efficiently generates rotational flows at each of upper and lower portions of the blade chamber  210  by the circumference center guider  110  and the blade center guider  220  as described above, thereby making it possible to improve the pumping performance. At the same time, the impact of the fluid passing through the blade chamber  210  is decreased, thereby making it possible to decrease the high frequency noise. 
         [0043]    Here, the impeller as described above is an impeller applied to an open channel type vehicle fuel pump in which several blades  200  are formed at the impeller body  100 , such that all of an upper side, a lower side, and an outer side of the blade chamber  210  are opened. That is, in the open channel type vehicle fuel pump, the fuel introduced into the blade chamber  210  is pushed in the outward direction of the circumferential surface of the impeller body  100  by the rotation of the impeller, such that the rotational flow is formed. 
         [0044]    Here, the impeller  1000  for a fuel pump of a vehicle according to the present invention may further include a side ring  300  formed on outer circumferential surfaces of the plurality of blades  200  so as to form the blade chambers  210  allowing discharge and introduction of the fuel to be made and allowing the rotational flows to be formed at the upper and lower sides of the blade  200 , respectively. 
         [0045]    That is, the impeller  1000  for a fuel pump of a vehicle according to the present invention may be applied to a side channel type vehicle fuel pump in which the upper and lower sides of the blade chamber  210  are opened and the outer side thereof is closed by the side ring  300 , such that the discharge and the introduction of the fuel are made at only the upper and lower sides of the blade chamber  210 . 
         [0046]    Therefore, in the side channel type impeller in which an entire introduced fuel passes through the blade chamber  210  and is then discharged, when the upper and lower blades  200   a  and  200   b  are formed at different angles to decrease the impact of the fluid, the high frequency noise may be further decreased. 
         [0047]    In addition, the side ring  300  includes a guider formed in a protrusion form at the center thereof along an inner circumferential surface thereof and corresponding to the circumference center guider  110  formed on the outer circumferential surface of the impeller body  100 , thereby making it possible to allow the rotational flow of the fuel to be more efficiently generated in the blade chamber  210 . 
         [0048]    In the impeller for a fuel pump of a vehicle according to the present invention, a magnitude of high frequency fluid noise due to high speed rotation of the impeller may be decreased. 
         [0049]    In addition, the flow energy loss of the fluid is decreased due to the decrease in the impact of the fluid, such that pumping efficiency is improved. 
         [0050]    The present invention is not limited to the above-mentioned exemplary embodiments but may be variously applied, and may be variously modified by those skilled in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims.