Electrical machine

DETAILED DESCRIPTION Accordingly, it is an object of present invention to provide an electrical machine, which, due to separate cooling circulation for a stator and for a rotor makes possible an independent cooling of the component.
In particular with the use of different cooling media for stator and rotor, for example water and air, an independent cooling as well as an optimization of a preferable cooling medium passage with respect to a temperature load can be provided.
The cooling circulations which are independent from one another can be varied with respect to their volumes streams and optimized.
In accordance with a preferable embodiment of the invention, the cooling circulation, when operational temperature of the electrical machine is reached, can be switched off individually and independently from one another.
It is advantageous when the stator has a cooling jacket which is joined with an inner surface in a substantially cylindrical housing of the electrical machine and has at least one ring-shaped cooling passage.
In order to guarantee a large-surface and effective cooling, it is however advantageous to extend the cooling passage over a great surface of the cooling jacket, for example meander-or spiral shaped in a peripheral direction of the housing.
Also, several cooling passages can be provided in the cooling jacket which for example are connected with one another by passages and/or separated from one another by webs.
The inventive so-called hybrid cooling of the electrical machine can be coupled in an advantageous manner with a liquid cooling circulation of the internal combustion engine.
Preferably, a separating valve which is operating electrically or in another manner can be provided.
It is also possible to provide a cooling circulation for electrical machines which is independent from the cooling circulation of the internal combustion engine.
For circulation of the cooling liquid, mechanically or electrically operated pump can be used.
The circulation can be also performed by heating, or in other words in accordance with the thermo siphone principle