Electric Water Pump

Abstract

An electric water pump may include a stator generating a magnetic field, a rotor rotated by the magnetic field, a pump cover, a body having a volute chamber with the pump chamber, a stator chamber and a rotor chamber, the stator being mounted in the stator chamber and the rotor being mounted in the rotor chamber, a shaft fixed to the rotor, an impeller fixed to the shaft in the volute chamber, a driver case mounted at a rear end of the body and having a rear surface opened backward and formed of a driver chamber therein, and a driver mounted in the driver chamber and applying a control signal to the stator, wherein the case surface is provided with an insert portion protruded forward from an external circumference thereof and inserted in a rear end portion of the body, and a fixing groove in which the insert portion is inserted.

1 . An electric water pump apparatus including:
 a stator generating a magnetic field according to a control signal;   a rotor enclosed by the stator and rotated by the magnetic field generated at the stator;   a pump cover having an inlet through which coolant flows in and an outlet through which pressurized coolant flows out;   a body having:
 a front surface forming a volute chamber between the pump cover and the front surface; 
 a stator chamber formed at an outer portion of the body in a radial direction, wherein the stator is mounted in the stator chamber; and 
 a rotor chamber formed at an inner portion of the body in a radial direction, wherein the rotor is mounted in the rotor chamber; 
   a shaft having a central axis, fixed to the rotor so as to rotate together with the rotor about the central axis thereof, and mounted in the rotor chamber; and   an impeller fixed to a front portion of the shaft so as to rotate together with the shaft, pressurizing the coolant having flowed in through the inlet, and mounted in the volute chamber.   
     
     
         2 . The electric water pump apparatus of  claim 1 , further including:
 a driver case detachably mounted at a rear end of the body, formed of a case surface at a front surface thereof, having a rear surface opened backward, and including a driver chamber therein, and   a driver mounted in the driver chamber and applying the control signal to the stator,   wherein the case surface is provided with an insert portion protruded forward from an external circumference thereof and detachably inserted in a rear end portion of the body, and a fixing groove in which the insert portion is inserted and that prevents rotation of the stator is formed at an external circumference of a rear end of the stator.   
     
     
         3 . The electric water pump apparatus of  claim 2 , wherein a first bearing is disposed between the shaft and the front surface of the body in order to reduce rotational friction of the shaft. 
     
     
         4 . The electric water pump apparatus of  claim 3 , wherein the rotor is formed in an unsymmetrical shape so as to generate thrust toward the front surface of the body. 
     
     
         5 . The electric water pump apparatus of  claim 4 , wherein a cup is mounted between the first bearing and the rotor on the shaft in order to prevent interference and collision of the shaft and the first bearing by the thrust, and a thrust ring is mounted between the cup and the first bearing for smooth rotation of the shaft. 
     
     
         6 . The electric water pump apparatus of  claim 5 , wherein the cup is made of a rubber material and the thrust ring is made of a ceramic material. 
     
     
         7 . The electric water pump apparatus of  claim 3 , wherein a second bearing is disposed between a rear end portion of the shaft and the front surface of the driver case in order to reduce the rotational friction of the shaft. 
     
     
         8 . The electric water pump apparatus of  claim 7 , wherein the second bearing is disposed between a step portion of the shaft at a rear side thereof and the front surface of the driver case in order to reduce the rotational friction of the shaft. 
     
     
         9 . The electric water pump apparatus of  claim 1 , wherein the stator includes:
 a stator core formed by stacking a plurality of pieces made of a magnetic material,   an insulator connecting pieces of the stator core to each other,   a coil coiling the stator core so as to form a magnetic path, and   a stator case wrapping and sealing the stator core, the insulator, and the coil.   
     
     
         10 . The electric water pump apparatus of  claim 9 , wherein a fixing groove is formed at an external circumference of a rear end of the stator case. 
     
     
         11 . The electric water pump apparatus of  claim 9 , wherein an interior circumference of the stator case forms a part of the rotor chamber. 
     
     
         12 . The electric water pump apparatus of  claim 11 , wherein the rotor chamber is fluidly connected to the volute chamber, and the stator chamber is fluidly closed and sealed to the rotor chamber. 
     
     
         13 . The electric water pump apparatus of  claim 12 , wherein a stator groove is formed at an interior circumference of the stator case along a length direction of the stator such that foreign substances attached to the stator are removed along the stator groove by coolant flow in the rotor chamber. 
     
     
         14 . The electric water pump apparatus of  claim 9 , wherein a plurality of damping holes for diminishing vibration and noise according to rotation of the rotor are formed at the stator case. 
     
     
         15 . The electric water pump apparatus of  claim 9 , wherein the stator case is made of a bulk mold compound including a potassium family that has a low coefficient of contraction. 
     
     
         16 . The electric water pump apparatus of  claim 15 , wherein the stator further includes:
 a Hall sensor detecting a position of the rotor, and   a Hall sensor board controlling the control signal supplied to the stator according to a position of the rotor detected by the Hall sensor,   wherein the Hall sensor and the Hall sensor board are also wrapped and sealed by the stator case.   
     
     
         17 . The electric water pump apparatus of  claim 1 , wherein the rotor includes:
 a rotor core having a hollow cylindrical shape and made of a magnetic material,   a permanent magnet mounted at an exterior circumference of the rotor core,   a rotor cover mounted at both distal ends of the rotor core and the permanent magnet so as to fix the rotor core and the permanent magnet together, and   a rotor case wrapping an exterior circumference of the rotor core and the permanent magnet together so as to fix the rotor core and the permanent magnet in a state that the rotor core and the permanent magnet are mounted at the rotor cover.   
     
     
         18 . The electric water pump apparatus of  claim 17 , wherein the rotor case is made of a bulk mold compound including a potassium family that has a low coefficient of contraction. 
     
     
         19 . The electric water pump apparatus of  claim 17 , wherein a first bearing is disposed between the shaft and the front surface of the body in order to reduce rotational friction of the shaft and wherein a cup is mounted between the first bearing and the rotor on the shaft in order to prevent interference and collision of the shaft and the first bearing by a thrust, and a thrust ring is mounted between the cup and the first bearing for smooth rotation of the shaft.