Electric coolant pump having a flow-cooled control circuit

Abstract

The invention relates to an electric coolant pump for a coolant circuit of an internal combustion engine, having a radially accelerating pump impeller and a spiral housing section of a pump housing. A control circuit is arranged about an inlet on the side of the pump housing opposing the electric engine, and is accommodated in an ECU chamber. An open side of the pump chamber and an open side of the ECU chamber are separated by a heat-exchange cover, which is opened into the pump chamber at a mouth of the inlet, wherein a material from which the ECU chamber is made has a lower heat conductivity than a material from which the heat-exchange cover is made.

1 . An electric coolant pump configured for a coolant circuit of an internal combustion engine, comprising:
 an electric motor with a pump shaft;   a pump impeller which radially accelerates a coolant to be conveyed and which is arranged on the pump shaft and is driven by the electric motor;   a pump housing with a pump chamber into which the rotably supported pump shaft extends and in which the pump impeller is accommodated within a spiral housing section that encloses a radial circumference of the pump chamber;   a pump inlet which, on the side of the pump housing opposite the electric motor, leads into the pump chamber and is axially directed to the pump impeller as well as an outlet which, at a circumferential section of the spiral housing section, is directed in a tangentially discharging direction;   a control circuit which, on the side of the pump housing opposing the electric motor, is situated around the pump inlet and accommodated within an ECU chamber;   characterized in that   the pump chamber is opened to the side of the pump housing opposing the electric motor and the ECU chamber is opened to the side facing the pump chamber; and   the opened side of the pump chamber and the opened side of the ECU chamber are separated by a heat-exchange cover, which is opened at a mouth of the puma inlet into the pump chamber,   a material from which the ECU chamber is made having a lower heat conductivity than a material from which the heat-exchange cover and/or the spiral housing section is made.   
     
     
         2 . The electric coolant pump according to  claim 1 , wherein the heat-exchange cover is made of aluminum or an aluminum alloy. 
     
     
         3 . The electric coolant pump according to  claim 1 , wherein the ECU chamber is formed in a molded piece of plastics. 
     
     
         4 . The electric coolant pump according to  claim 1 , wherein the spiral housing section is made of aluminum or an aluminum alloy that is suitable in terms of manufacturing for a pressure die casting process, an injection molding process or a 3D printing process. 
     
     
         5 . The electric coolant pump according to  claim 1 , wherein an unpopulated side of a circuit carrier of the control circuit is in planar contact with the heat-exchange cover. 
     
     
         6 . The electric coolant pump according to  claim 5 , wherein the circuit carrier of the control circuit is a lead frame. 
     
     
         7 . The electric coolant pump according to  claim 1 , wherein the control circuit comprises a printed circuit board that is preferably held in the ECU chamber spaced apart from the circuit carrier by means of a electrically connecting contact pins. 
     
     
         8 . The electric coolant pump according to  claim 1 , wherein
 the pump impeller as the impeller is formed with a central inflow opening and radial outlet openings and comprises steps formed at a casing portion between the inflow opening and the radial outlet openings in a radial and axial direction; and   the heat-exchange cover comprises radially alternating protrusions and recesses, wherein a protrusion and an adjacent recess being respectively radially associated with a step of the pump impeller being arranged axially on the opposite side, and axial shapes of the protrusions being graded to the associated steps in a complementary manner so that a gap is formed between the associated recesses and the steps.   
     
     
         9 . The electric coolant pump according to  claim 1 , wherein the heat-exchange cover comprises a collar that encloses the inlet and/or forms the mouth of the inlet. 
     
     
         10 . The electric coolant pump according to  claim 1 , wherein the ECU chamber and the inlet are formed integrally. 
     
     
         11 . The electric coolant pump according to  claim 1 , further comprising a busbar rail which extends through a channel in the pump housing and establishes an electric connection between the control circuit and a stator of the electric motor. 
     
     
         12 . The electric coolant pump according to  claim 11 , wherein a clearance remains between an internal surface section of the channel and an external surface section of the busbar rail that enables a pressure equalization between an internal space of a motor housing and the ECU chamber. 
     
     
         13 . The electric coolant pump according to  claim 1 , wherein the ECU chamber comprises an opening which is closed by a diaphragm that is impervious to liquids and open to gas. 
     
     
         14 . The electric coolant pump according to  claim 1 , furthermore comprising a metal seal between the pump housing ROM and the heat-exchange cover. 
     
     
         15 . The electric coolant pump according to  claim 1 , furthermore comprising a lip seal between the pump housing and the pump shaft. 
     
     
         16 . The electric coolant pump according to  claim 1 , furthermore comprising an aluminum leakage seal between the pump housing and the electric motor. 
     
     
         17 . The electric coolant pump according to  claim 1 , wherein a motor housing, by means of which the electric motor is attached to the pump housing, is made of aluminum. 
     
     
         18 . The electric coolant pump according to  claim 1 , wherein a leakage chamber is formed between a face side of the electric motor and an opposing outline of the spiral housing section in the pump housing.