Controllable coolant pump with an electro-hydraulic baffle plate adjustment

Abstract

A controllable coolant pump of a cooling circuit for an internal combustion engine, having a pump housing, in which a pump shaft with associated impeller is rotatably arranged. The impeller conveys a coolant as a volume flow via an intake connection in a pressure or spiral channel of the coolant pump. The volume flow can be influenced by a baffle plate which encloses the outside of the impeller, the push rod of the baffle plate being guided in the pump shaft. In connection with an actuator the baffle plate can be continuously adjusted between two limit positions against the force of a spring. A control element, which has an electro-hydraulic action and which is integrated into the pump shaft, serves as an actuator, wherein the pressurized coolant in the coolant pump is provided as a hydraulic fluid.

1 - 9 . (canceled) 
     
     
         10 . A controllable cooling pump of a cooling circuit of an internal combustion engine, comprising:
 a pump housing;   a rotatably supported pump shaft connected to an impeller driven by a traction mechanism drive via an associated drive pulley, the impeller conveying a coolant as a volume flow into a pressure or spiral channel of the coolant pump via an intake connection;   a baffle plate capable of influencing the volume flow, the baffle plate encompassing the impeller on the outside and a push rod associated with the baffle plate being guided in the pump shaft, and the baffle plate being continuously adjustable between two end positions against the force of a spring in connection with an actuator;   the actuator being an electro-hydraulically operating final control element integrated into the pump shaft and provided for positioning the baffle plate, with the aid of which a working chamber or a pressure chamber is filled with pressurized coolant of the coolant pump as hydraulic fluid.   
     
     
         11 . The coolant pump as recited in  claim 10  wherein the actuator has a solenoid switch, the actuator positioned in a stationary manner, the solenoid switch acting upon a pump piston guided directly or indirectly in a longitudinal bore of the pump shaft designed as a hollow shaft, the pump piston together with the push rod or a pressure piston assigned to the push rod delimiting the working chamber of the pump shaft, which is filled with hydraulic fluid. 
     
     
         12 . The coolant pump as recited in  claim 11  wherein the solenoid switch engages with an end-side receptacle of the pump shaft, and its centric switching axis interacts with the pump piston. 
     
     
         13 . The coolant pump as recited in  claim 10  wherein the hydraulic fluid flows into the working chamber of the pump shaft via an inlet as a function of a position of a pump piston. 
     
     
         14 . The coolant pump as recited in  claim 10  wherein the hydraulic fluid flows into the working chamber of the pump shaft via a one-way valve integrated into the inlet in the event of a pressure difference or a pressure gradient. 
     
     
         15 . The coolant pump as recited in  claim 11  further comprising a one-way valve allowing a pressure medium to flow in the direction of the pressure piston inserted into the end of the longitudinal bore of the pump shaft on the end facing away from the solenoid switch. 
     
     
         16 . The coolant pump as recited in  claim 10  wherein a pressure piston connected to the baffle plate via a push rod is guided in a stepped bore of the pump shaft, the push rod being movable in a positionally fixed guide bush of the pump shaft, a spring being inserted between the pressure piston and the guide bush. 
     
     
         17 . The coolant pump as recited in  claim 10  further comprising a cartridge or guide sleeve pressed into the longitudinal bore of the pump shaft, which is designed to accommodate a pump piston, a one-way valve as well as a spring inserted between the pump piston and the one-way valve. 
     
     
         18 . The coolant pump as recited in  claim 10  wherein an actuation of the actuator is controlled as a function of at least one operating parameter of an internal combustion engine.