Charging device for an energy conversion device

Abstract

A charging device for an energy conversion device, e.g., a fuel cell, of a motor vehicle, has a rotor rotatably mounted on a housing of the charging device, the rotor having a shaft and at least two compressor wheels which are connected in rotationally fixed fashion to the shaft. The compressor wheels have wheel rear parts facing away from respective compressor wheel inlets, by which a medium that is to be supplied to the energy conversion device, e.g., air, is compressible. The wheel rear parts of the compressor wheels are matched to one another such that respective forces which are opposed to one another and which result from respective compressor wheel outlet forces impressed on the wheel rear parts substantially balance one another.

What is claimed is: 
     
         1 . A charging device for a fuel cell of a motor vehicle, comprising:
 a housing; and   a rotor rotatably mounted on the housing, wherein the rotor includes a shaft and at least two compressor wheels connected to the shaft in rotationally fixed fashion, wherein each compressor wheel has a wheel rear part facing away from a respective compressor wheel inlet, wherein the at least two compressor wheels compress air which is to be supplied to the fuel cell, and wherein the wheel rear parts of the two compressor wheels are matched to one another such that opposing forces resulting from respective compressor wheel outlet pressures impressed on the wheel rear parts substantially balance one another.   
     
     
         2 . The charging device as recited in  claim 1 , wherein the wheel rear parts are matched to one another with regard to their diameter. 
     
     
         3 . The charging device as recited in  claim 2 , wherein the rotor is mounted by at least one air bearing in the axial direction. 
     
     
         4 . The charging device as recited in  claim 2 , wherein the at least two compressor wheels for compressing air are connected in series. 
     
     
         5 . The charging device as recited in  claim 2 , wherein the at least two compressor wheels for compressing air are connected in parallel. 
     
     
         6 . The charging device as recited in  claim 2 , further comprising:
 a drive motor configured to drive the rotor.   
     
     
         7 . The charging device as recited in  claim 2 , wherein the rotor has a turbine wheel connected in rotationally fixed fashion to the shaft, and wherein the rotor is driven by the turbine wheel. 
     
     
         8 . The charging device as recited in  claim 7 , wherein the turbine wheel is driven by an exhaust gas of the fuel cell.