Controllable coolant pump with a multi-part modular construction

Abstract

A controlled coolant pump of an internal combustion engine with a pump housing in which a pump shaft is rotatably supported and which has a belt wheel on one end side. A coolant is forced by a pump shaft impeller as a volume flow via a suction connection into a spiral channel of the coolant pump. The volume flow is influenced by a guide plate device that interacts with the impeller and has a guide plate that is continuously adjustable in the axial direction between two end positions and also includes an actuation unit that interacts with the pump shaft. The two-part pump shaft of the coolant pump includes modules that can be inserted into the pump housing assembled into one structural unit via an interface. The actuation unit allocated directly to a module includes a displacement pump with pump outlet valve and a guide plate device.

1 . A controlled coolant pump of an internal combustion engine, comprising: a pump housing, a pump shaft is supported in the pump housing for rotation and to which, on an end side, a belt wheel or a drive element is allocated, an impeller on the pump shaft that forces a coolant as a volume flow via a suction connection in a spiral channel of the coolant pump, the volume flow is adjustable by a guide plate device that interacts with the impeller and comprises a guide plate that is continuously adjustable in an axial direction of the pump shaft between two end positions, and an actuation unit that interacts with the pump shaft, the pump shaft is at least a two-part pump shaft that forms, with associated components, modules that can be preassembled individually and can be inserted into the pump housing assembled into one structural unit via at least one interface, and the actuation unit comprises a displacement pump allocated directly to a section of the pump shaft. 
     
     
         2 . The coolant pump according to  claim 1 , wherein the pump shaft includes two of the modules assembled via one of the interface, the first one of the modules includes a sub-shaft with an associated roller bearings, a sliding ring seal, a displacement pump and a pump outlet valve of the actuation unit and the second one of the modules comprises an impeller shaft with the impeller and the guide plate device that interacts with the actuation unit and includes the guide plate, a piston, and a push rod. 
     
     
         3 . The coolant pump according to  claim 1 , wherein the pump shaft includes three of the modules assembled via two of the interfaces, a first one of the modules comprises a sub-shaft with associated roller bearings and a sliding ring seal, a second one of the modules includes an intermediate shaft, the displacement pump, and a pump outlet valve, and a third one of the modules includes the impeller shaft with the impeller and the guide plate device that interacts with the actuation unit. 
     
     
         4 . The coolant pump according to  claim 1 , wherein the pump shaft includes three of the modules assembled via the interfaces, a first one of the modules includes a sub-shaft with the displacement pump integrated therein constructed as an axial piston pump and roller bearings and a sliding ring seal, a second one of the modules comprises an intermediate shaft and a pump outlet valve, and a third one of the modules includes of the impeller shaft with the impeller and the guide plate device that interacts with the actuation unit. 
     
     
         5 . The coolant pump according to  claim 4 , wherein the interfaces between at least two of the shafts, the sub-shaft, the impeller shaft, or the intermediate shaft are provided as an interference fit with at least one of a non-positive or positive fit connection. 
     
     
         6 . The coolant pump according to  claim 5 , wherein the impeller shaft that is allocated to the impeller and includes a cylinder for the piston of the actuation unit surrounds the sub-shaft or the intermediate shaft on an end side with non-positive and positive fit connection. 
     
     
         7 . The coolant pump according to  claim 6 , characterized in that a diameter (D 2 ) of the piston of the actuation unit≧a diameter (D 1 ) of the sub-shaft. 
     
     
         8 . The coolant pump according to  claim 4 , wherein in an area of the interface, the intermediate shaft forms a central projection that extends in the axial direction and is pressed into an opening of the sub-shaft with non-positive and positive fit connections. 
     
     
         9 . The coolant pump according to  claim 4 , wherein for forming a fail-safe device, a force is applied to the piston by a compression spring inserted in the cylinder of the impeller shaft in a direction of the pump outlet valve. 
     
     
         10 . A method for completion or assembly of a coolant pump according to  claim 1 , comprising the following steps:
 positioning the pump housing for completion of the coolant pump;   preassembling of two or three of the modules which comprises the sub-shaft and the impeller shaft or also the intermediate shaft;   joining of the two or three of the modules by application of force in connection with a pressing tool to form a pump shaft;   introducing, aligning, and fixing of the pump shaft in a final position in the pump housing; and   fastening of the belt wheel on the sub-shaft.