Fluid pump for delivering cooled working fluid in an engine cooling system

Abstract

A fluid pump for delivering cooled working fluid in an engine cooling system includes a housing unit defining front and rear chambers, an inlet disposed upstream of a central region of the front chamber, an outlet disposed downstream of a surrounding region of the front chamber, a canister member dividing the rear chamber into stator- and rotor-side spaces for receiving a stator and a rotor, respectively, a hollow shaft which is rotated with the rotor to turn an impeller in the central region and which defines a passage, and an auxiliary conduit communicated with the inlet and the rear chamber so as to divert part of the working fluid to flow through the internal duct and the passage, thereby diffusing heat generated within the housing unit.

1 . A fluid pump for delivering cooled working fluid in an engine cooling system, said fluid pump comprising:
 a housing unit defining an accommodation chamber which extends along a central axis, and having a partition wall which extends radially to watertightly separate said accommodation chamber into front and rear chambers, said rear chamber having a rear peripheral wall which surrounds the central axis, and a rear mount wall which extends radially and which has an internal duct that extends therethrough along the central axis, said front chamber having a central region and a surrounding region that are disposed radially opposite to each other;   an inlet which is disposed forwardly of said front chamber and upstream of said central region;   an outlet which is disposed downstream of said surrounding region;   a canister member disposed in said rear chamber, and configured to watertightly separate said rear chamber into stator-side and rotor-side spaces, said canister member including
 a front tubular end which is secured to said partition wall, and 
 a rear end wall which extends radially to interrupt fluid communication between said stator-side space and said internal duct, and which has an entry duct that extends along the central axis to be in fluid communication with said internal duct; 
   a stator which is disposed in said stator-side space;   a hollow shaft which is disposed in said rotor-side space and which has an output spindle that extends into said central region, said hollow shaft defining a passage which extends along the central axis to communicate said internal duct with said central region;   a rotor which is mounted in said rotor-side space to rotate said outer spindle about the central axis;   an impeller which is mounted in said central region to be rotated with said output spindle, and which is configured to compel the cooled working fluid introduced through said inlet to flow towards said surrounding region and out through said outlet when said impeller is rotated with said output spindle; and   an auxiliary conduit which has an in-flow port that is disposed upstream of said central region and downstream of said inlet, and which extends to be in fluid communication with said internal duct so as to divert part of the introduced cooled working fluid to directly flow through said internal duct and said passage and out of said output spindle, thereby diffusing heat that is generated as a result of rotation of said rotor.   
     
     
         2 . The fluid pump according to  claim 1 , wherein said surrounding region is configured to extend spirally relative to the central axis from said central region and to terminate at said outlet. 
     
     
         3 . The fluid pump according to  claim 1 , wherein said auxiliary conduit includes a rear segment which is disposed rearwardly of said rear mount wall of said housing unit, and which extends radially to be in fluid communication with said internal duct, an elongated segment which extends forwardly from said rear segment along said rear peripheral wall, and a front segment which extends toward the central axis from said elongated segment and which defines said in-flow port, said in-flow port being in fluid communication with said inlet. 
     
     
         4 . The fluid pump according to  claim 3 , wherein said housing unit has a cover which has a surrounding wall that is connected to said partition wall, that extends forwardly and towards the central axis to terminate at said inlet, and that cooperates with said partition wall to define said front chamber, said front segment of said auxiliary conduit being disposed on said surrounding wall and extending forwardly of said surrounding region and below said inlet to define said in-flow port of said auxiliary conduit. 
     
     
         5 . The fluid pump according to  claim 1 , wherein said partition wall has an annular bearing wall which surrounds the central axis, said hollow shaft having front and rear journalled ends that are mounted rotatably and respectively on said annular bearing wall and said rear end wall about the central axis, said front jounalled end extending into said central region to serve as said output spindle.