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.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a charging device for an energy conversion device, e.g., a fuel cell.[0003]2. Description of the Related Art[0004]Published Japanese patent application JP 2001 / 263291 discloses a supporting structure for a high-speed compressor having an electric motor that includes a rotor shaft mounted by magnetic bearings.[0005]U.S. Pat. No. 6,196,809 B1 discloses a two-stage compressor having two compressor wheels that are attached to opposite end regions of a shaft. For the axial mounting, magnetic axial bearings are provided that absorb forces in the axial direction of the shaft.[0006]U.S. Pat. No. 6,155,802 discloses a turbo compressor having a first and a second compression chamber, and having a shaft that is connected to two compressor wheels.[0007]U.S. Pat. No. 6,450,780 B1 discloses a method for producing a gas under pressure using a compressor that is coupled to an electrical machine. The com...

AI Technical Summary

Benefits of technology

The present invention provides a charging device for an energy conversion device, such as a fuel cell, of a motor vehicle. The charging device includes a rotor that is rotatably mounted on a housing. The rotor has at least two compressor wheels that are connected to it in rotationally fixed fashion. The compressor wheels have wheel rear parts that face away from the inlet of the wheel. This design ensures that the forces created by the compressor wheels cancel out, resulting in no or low frictional losses and efficient operation of the charging device. The compressor wheels can be connected in series to one another, which further enhances the efficiency of the charging device. The invention also provides a design that reduces the complexity and part count of the charging device, keeping costs low.

Problems solved by technology

As a result of their design, such air bearings produce higher frictional losses than do other kinds of bearings such as ball bearings; the predominant part of these frictional losses, for example two-thirds of the overall frictional losses, occur in particular in the absorption of bearing forces in the axial direction of the shaft.

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