Patent Publication Number: US-2023160394-A1

Title: Impeller for water pump

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Korean Patent Application No. 10-2021-0160004 filed on Nov. 19, 2021, and to Korean Patent Application No. 10-2022-0113544 filed on Sep. 7, 2022. The entire contents of the above-listed application are hereby incorporated by reference for all purposes. 
     TECHNICAL FIELD 
     The following disclosure relates to an impeller for a water pump that is coupled to a driven rotating shaft and pumping a fluid by a rotational force. 
     BACKGROUND 
     A water pump is a device for circulating cooling water to an engine or a heater for engine cooling or interior heating. This water pump may be roughly classified into a mechanical water pump and an electric water pump. 
     The mechanical water pump is a pump connected to a crankshaft of the engine and driven by rotation of the crankshaft, and the electric water pump is a pump driven by rotation of a motor controlled by a control device. 
     The electric water pump may roughly include a motor part including a housing, a stator and a rotor, and a pump part including an impeller and an impeller casing. In addition, the stator may be positioned in and fixed to the housing, the rotor may be disposed in the stator while being spaced apart therefrom, the impeller may be coupled to a rotating shaft of the rotor, and the impeller casing may be coupled to the housing to cover and block the impeller. The fluid may thus be pumped by rotation of the impeller. 
     However, the impeller of the water pump may generally have a plurality of blades arranged at equal intervals, and significant noise may thus occur due to the rotation of the impeller when the water pump is operated to pump the fluid. 
     RELATED ART DOCUMENT 
     Patent Document 
     KR 10-2017-0046238 A (May 2, 2017) 
     SUMMARY 
     Embodiments of the present disclosure are directed to providing an impeller for a water pump which may reduce noise occurring when the impeller is rotated. 
     In one general aspect, an impeller for a water pump includes: a main plate; and a plurality of blades arranged on one surface of the main plate, and spaced apart from each other in a circumferential direction of the main plate, wherein the plurality of blades are non-equal interval types in which the blades are spaced apart from each other at intervals not equal to each other. 
     The blade interval at which the plurality of blades are spaced apart from each other may have an angle at which tips of the plurality of blades are spaced apart from each other. 
     The blade intervals adjacent to each other may be different from each other. 
     The blade intervals may be all different from each other. 
     The plurality of blades may have blade intervals formed different from each other and positioned opposite to each other based on a center of the main plate. 
     The blade intervals may be arranged randomly with no regularity. 
     The plurality of blades may have different curved degrees. 
     The plurality of blades may have different thicknesses. 
     When “N” indicates the number of blades and “A” indicates the blade interval, the blade interval may be formed within an angle range that satisfies Equation 1 below: 
     
       
         
           
             
               
                 
                   
                     
                       
                         360 
                         ⁢ 
                         ° 
                       
                       N 
                     
                     × 
                     
                       0 
                       . 
                       9 
                     
                   
                   ≤ 
                   A 
                   ≤ 
                   
                     
                       
                         360 
                         ⁢ 
                         ° 
                       
                       N 
                     
                     × 
                     
                       1.1 
                       . 
                     
                   
                 
               
               
                 
                   ( 
                   
                     Equation 
                     ⁢ 
                         
                     1 
                   
                   ) 
                 
               
             
           
         
       
     
     In another general aspect, a water pump includes: a motor housing having a shape of a container with an open upper side; a stator positioned in the motor housing; a lower casing coupled to the upper side of the motor housing, and including a rotor accommodating part that protrudes downward, has a rotor accommodating space concave downward from an upper surface thereof, and is inserted into the stator; an upper casing coupled to an upper side of the lower casing, having an impeller accommodating space by being coupled with the lower casing, and including an inlet through which a fluid is introduced and an outlet through which the fluid is discharged by communicating with impeller accommodating space; the impeller for a water pump of claim  1  rotatably positioned in the impeller accommodating space; and a rotor rotatably positioned in the rotor accommodating space of the lower casing and coupled to the impeller. 
     The impeller for a water pump may further include a lower plate positioned opposite to the main plate and coupled to the plurality of blades, and the main plate and the plurality of blades of the impeller for a water pump may be integrally formed with each other, and the lower plate may be integrally formed with the rotor. 
     The impeller for a water pump may have a through hole positioned in a center of the main plate and passing through both sides thereof. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1  to  3    are a perspective view, an upper plan view, and a lower plan view showing an impeller for a water pump according to an embodiment of the present disclosure, respectively. 
         FIG.  4    is a plan view showing an equal-interval type impeller whose blades have the equal intervals therebetween according to the prior art. 
         FIG.  5    is a plan view showing a non-equal interval type impeller whose blades have non-equal intervals therebetween according to an embodiment of the present disclosure. 
         FIG.  6    is a graph showing measured noise of a water pump using the prior equal-interval type impeller of  FIG.  4   . 
         FIG.  7    is a graph showing measured noise of a water pump using the non-equal interval type impeller according to the present disclosure of  FIG.  5   . 
         FIG.  8    is data showing the noise of the water pump using the prior equal-interval type impeller of  FIG.  4    and the noise of the water pump using the non-equal interval type impeller according to the present disclosure of  FIG.  5   . 
         FIG.  9    is test data of performances of the water pump using the prior equal-interval type impeller and the water pump using the non-equal interval type impeller according to the present disclosure. 
         FIGS.  10  to  12    are an assembled perspective view, an exploded perspective view, and a front sectional view showing a water pump including the impeller for a water pump according to another embodiment of the present disclosure, respectively. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an impeller for a water pump of the present disclosure is described in detail with reference to the accompanying drawings. 
       FIGS.  1  to  3    are a perspective view, an upper plan view, and a lower plan view showing an impeller for a water pump according to an embodiment of the present disclosure, respectively. 
     As shown in the drawings, the impeller for a water pump according to an embodiment of the present disclosure may roughly include a main plate  510  and a plurality of blades  530 . 
     Referring to  FIGS.  1  to  3   , the main plate  510  may have a disc shape, for example, and include a through hole  501  passing through both sides thereof for a fluid to pass through its center. In addition, the main plate  510  may slightly protrude toward the other side (downward) from the outside to the inside in a radial direction, and the through hole  501  may extend from an inner end of the main plate  510  to the other side in the radial direction. The main plate  510  may have any of various other shapes. 
     The plurality of blades  530  may be arranged on one surface of the main plate  510 , and spaced apart from each other in a circumferential direction of the main plate  510 . In addition, the plurality of blades  530  may have a root part, which is the inner end thereof in the radial direction, disposed to be spaced apart from the center of the main plate  510 , and a tip, which is an outer end thereof in the radial direction, disposed to be coincident with the outer end of the main plate  510  in the radial direction. In addition, the plurality of blades  530  may have a curved shape curved from the root to the tip in one direction, and a shape of a curved plate having a thickness smaller than its height. The plurality of blades  530  may have any of various other shapes. 
     Here, the plurality of blades  530  may be a non-equal interval type in which the blades  530  are spaced apart from each other at intervals not equal to each other. For example, when the interval at which the plurality of blades  530  are spaced apart from each other is referred to as a blade interval, the blade interval may have an angle at which the tips of the plurality of blades  530  are spaced apart from each other. That is, the blade interval of any two adjacent blades  530  may not be the same as each other. In other words, any one or more of the blade intervals may be different from the rest blade intervals. 
     Therefore, when the impeller for a water pump according to the present disclosure is used in a water pump to pump the fluid, some frequency noise component occurring by each blade during rotation of the impeller may not overlap each other, thus reducing the noise. 
     In addition, in the impeller for a water pump according to the present disclosure, the blade intervals adjacent to each other may be different from each other. That is, as shown in the drawings, it may be seen that the separation angles between two adjacent blades may be different from each other. It is thus possible to further reduce the overlapping of the frequency components of the noise occurring by each blade during the rotation of the impeller. 
     In addition, in the impeller for a water pump according to the present disclosure, the blade intervals may be all different from each other. That is, all the blade intervals may be different from each other. For example, when A1 to A9 respectively indicate the blade intervals, all of A1 to A9 may have different angles. In addition, the blade intervals may be arranged randomly with no particular regularity. 
     Therefore, when the impeller for a water pump according to the present disclosure is used in the water pump to pump the fluid, any frequency noise component occurring by each blade during the rotation of the impeller may not overlap each other, thus significantly reducing the noise. 
     In addition, the plurality of blades  530  may have blade intervals formed different from each other and positioned opposite to each other based on the center of the main plate  510 . For example, the blade intervals A5 and A6 positioned opposite to any blade interval A1 may respectively be different from the blade interval A1. 
     Therefore, when the impeller for a water pump according to the present disclosure is used in the water pump to pump the fluid, frequency noise component corresponding to half of a rotational speed of the impeller during the rotation of the impeller may not overlap each other, thus reducing the noise. 
     In addition, the plurality of blades  530  may have different curved degrees or different thicknesses. That is, the blade  530  may have a changed position of the tip by having the different curved degree or the different thickness in a state where the angles at which the blades  530  are arranged are the same as each other. Accordingly, the blade intervals may be different from each other. 
     In addition, when “N” indicates the number of blades  530  and “A” indicates the blade interval, the blade interval may be formed within an angle range that satisfies Equation 1 below. 
     
       
         
           
             
               
                 
                   
                     
                       
                         360 
                         ⁢ 
                         ° 
                       
                       N 
                     
                     × 
                     
                       0 
                       . 
                       9 
                     
                   
                   ≤ 
                   A 
                   ≤ 
                   
                     
                       
                         360 
                         ⁢ 
                         ° 
                       
                       N 
                     
                     × 
                     1.1 
                   
                 
               
               
                 
                   ( 
                   
                     Equation 
                     ⁢ 
                         
                     1 
                   
                   ) 
                 
               
             
           
         
       
     
     Here, the water pump may have increased pulsation and vibration and lower efficiency when the blade interval A is out of the range of Equation 1 above. Therefore, when the blade interval is set within an appropriate range as shown in Equation 1 above, it is possible to reduce the vibration and noise during the rotation of the impeller, and also secure reliable performance of the water pump using the impeller of the present disclosure. 
       FIG.  4    is a plan view showing an equal-interval type impeller whose blades have the equal intervals therebetween according to the prior art; and  FIG.  5    is a plan view showing the non-equal interval type impeller whose blades have the non-equal intervals therebetween according to an embodiment of the present disclosure.  FIGS.  4  and  5    show conditions where the impellers have the same size as each other, each include the same number of blades, i.e., seven blades, and have only different blade intervals. 
     In addition,  FIG.  6    is a graph showing measured noise of a water pump using the prior equal-interval type impeller of  FIG.  4   ;  FIG.  7    is a graph showing measured noise of a water pump using the non-equal interval type impeller according to the present disclosure of  FIG.  5   ; and  FIG.  8    is data showing comparison of the noise of the water pump using the prior equal-interval type impeller and the noise of the water pump using the non-equal interval type impeller according to the present disclosure. 
     As shown in the drawings, it may be seen that the water pump has the 7th and 14th noise generally reduced when using the non-equal interval type impeller of the present disclosure compared to when using the prior equal-interval type impeller, in particular, the 7th noise in an X direction and 14th noise in a Z direction, significantly reduced. 
       FIG.  9    is test data of performances of the water pump using the prior equal-interval type impeller and the water pump using the non-equal interval type impeller according to the present disclosure. 
     As shown in the drawing, it may be seen that the water pump using the non-equal interval type impeller of the present disclosure has almost no differences from the water pump using the prior equal-interval type impeller in terms of various performances, such as flow rate, fluid pressure, and current, or the like for each rotational speed. Therefore, the water pump using the non-equal interval type impeller of the present disclosure may reduce the noise and vibration while sufficiently securing the required performance. 
       FIGS.  10  to  12    are an assembled perspective view, an exploded perspective view, and a front sectional view showing the water pump including the impeller for a water pump according to another embodiment of the present disclosure, respectively. 
     As shown in the drawings, the water pump of the present disclosure may include a motor housing  300 , a stator  100 , a lower casing  210 , an upper casing  600 , the impeller  500  for a water pump, and a rotor  400 . 
     The motor housing  300  may have a shape of a concave container made of a metal material, an empty inside, and an open upper side. In addition, the motor housing  300  may have a blocked lower end and a side having a cylindrical shape, and a flange may protrude outward from an outer circumferential surface of an upper end thereof in a radial direction. 
     The stator  100  may include a core  110 , a plurality of teeth  120 , an insulator  130 , a coil  140 , and a plurality of terminals  150 . The stator  100  may be a stator used for a generally used motor, a brushless direct current (BLDC) motor, or the like, and may be any of various other types. 
     The lower casing  210  may have a lower setting groove  211  concave downward from an upper surface thereof to accommodate a portion of the impeller  500 , and a concave lower passage groove  212  positioned outside the lower setting groove  211  in a radial direction for a fluid discharged from the impeller  500  to flow. The rotor accommodating part  220  may be integrally formed with the lower casing  210  by injection molding, and have a shape of a concave container protruding downward from a center of a portion in which the lower seating groove  211  is positioned. In addition, in the rotor accommodating part  220 , a lower bearing mounting part  222  may be positioned at a lower bottom of a rotor accommodating space  221 , and a lower bearing  411  may be coupled to the lower bearing mounting part  222 . Here, the lower bearing  411  may include a bushing B which may support a lower end of a rotating shaft  410  of the rotor  400  in the radial direction, and a support pin P which may support the lower end of the rotating shaft  410  in an axial direction. Thus, the rotor  400  may be inserted into the rotor accommodating space  221  inside the rotor accommodating part  220 , and an outer circumferential surface of the rotor  400  may be spaced apart from an inner circumferential surface of the rotor accommodating part  220 . The lower end of the rotor  400  may thus be coupled to the lower bearing  411 , and the rotor  400  may thus be smoothly rotated. In addition, the rotor accommodating part  220  of the lower casing  210  may be inserted into and coupled to the stator  100 . 
     The upper casing  600  may be coupled to an upper side of the lower casing  210 , and have an impeller accommodating space  601  accommodating the impeller  500  by being coupled with the lower casing  210 . In addition, an upper seating groove  630  may be positioned concave upward in a lower surface of the upper casing  600  to accommodate a portion of the impeller  500 , and the lower seating groove  211  and the upper seating groove  630  may form the impeller accommodating space  601 . In addition, a concave upper passage groove  632  may be positioned to correspond to the lower passage groove  212  of the lower casing  200  in the lower surface of the upper casing  600  for the fluid discharged from the impeller  500  to flow. In addition, the upper casing  600  may have an open center in a vertical direction. Therefore, the upper seating groove  630  and an inlet  610  may communicate with each other, and an outlet  620  may be connected to the upper passage groove  632  and the lower passage groove  212 . In addition, an upper bearing mounting part  602  may be positioned inside the inlet  610  of the upper casing  600 , and an upper bearing  412  may be coupled to the upper bearing mounting part  602 . Here, the upper bearing mounting part  602  may be disposed in a portion in which an inflow passage  611  is positioned, and the upper bearing mounting part  602  may be fixed to a support part  612  protruding from an inner circumferential surface of the inflow passage  611 , and the fluid may thus smoothly pass between the support parts  612  to be introduced into the impeller  500 . Here, the upper bearing  412  may include the bushing B which may support an upper end of the rotating shaft  410  of the rotor  400  in the radial direction, and the support pin P which may support the upper end of the rotating shaft  410  in the axial direction. The upper end of the rotor  400  may thus be coupled to the upper bearing  412 , and the rotor  400  may thus be smoothly rotated. 
     The impeller  500  may serve to pump the fluid introduced into the inlet  610  of the upper casing  600  toward the outlet  620  by the rotation. For example, the impeller  500  may include the main plate  510  and the plurality of blades  530  integrally formed with each other, and further include a lower plate  520  integrally formed with a core part of the rotor  400 . Therefore, the plurality of blades  530  may have one side coupled to the main plate  510  and the other side coupled to the lower plate  520 . A through hole  501  positioned in the main plate  510  may communicate with the inlet  610  of the upper casing  600 . In addition, an outer circumference of the impeller  500  may be disposed close to the lower groove passage  212  and the upper passage groove  632 , and the fluid discharged from the impeller  500  may thus pass through a discharge passage  621  positioned by the passage grooves to be discharged through the outlet  620  of the upper casing  600 . 
     The fluid introduced into the inlet  610  of the upper casing  600  may thus be introduced into the impeller  500  through the inflow passage  611  and the through hole  501  in an upper center of the impeller  500 , may then have increased pressure by a centrifugal force generated by the rotation of the impeller  500  to flow into the discharge passage  621 , and then flow along the discharge passage  621  to be discharged to the outside through the outlet  620 . 
     As described above, the rotor  400  may be rotatably accommodated in the rotor accommodating space  221  of the lower casing  210 , and an outer circumferential surface of the rotor  400  may be spaced apart from an inner circumferential surface of the rotor accommodating part  220 . 
     As set forth above, the impeller for a water pump according to the present disclosure may reduce the noise occurring when the impeller is rotated by using a simple configuration of the changed intervals between the arranged blades. 
     The present disclosure is not limited to the above-described embodiments, and may be variously applied. In addition, the present disclosure may be variously modified by those skilled in the art to which the present disclosure pertains without departing from the gist of the present disclosure claimed in the claims.