Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-10-04
2002-09-24
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S054000, C310S058000, C310S06000A
Reexamination Certificate
active
06455959
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to motor vehicles, and more particularly to a cooling arrangement for an electrical machine of a vehicle, the electrical machine being connected to the engine block of the vehicle.
2. Description of the Related Art
Such electrical machines are, for example, synchronous machines for generating electrical energy. The generated electrical energy is then made available to all kinds of devices in the vehicle. Among other things, a heat loss, which as a rule results from copper losses and iron losses, is produced during the operation of such electrical machines. However, the heat loss in the electrical machine is undesirable, since it may lead to power losses of the machine and to damage of the latter in the worst case.
The electrical machine must therefore be cooled in order to reduce the heat loss produced in it. To this end, cooling arrangements independent of the electrical machine have been used heretofore. Such cooling arrangements contain, for example, heat exchangers or the like, which are connected to the coolant circuit via appropriate devices such as pumps, etc.
However, the known solutions have a number of disadvantages. First of all, the electrical machine itself has co be provided with appropriate cooling elements. Thus cooling of the electrical machine is only possible at a high design cost. Furthermore, a number of secondary units are required in order to provide a suitable circulation of the coolant. The known cooling arrangements are therefore also relatively costly.
In vehicles with a limited amount of space available in the engine compartment, the known cooling arrangements are particularly disadvantageous in that an excessive amount of the installation space, which is limited anyway, is taken up by a multiplicity of requisite secondary units. Finally, some of the secondary units, such as pumps for example, in turn consume electrical energy, a factor which has an adverse effect on the energy balance of the electrical machine.
SUMMARY OF THE INVENTION
Starting from the aforesaid prior art, it is an object of the present invention to provide a cooling arrangement with which the disadvantages described can be avoided. In particular, a cooling arrangement with which cooling of the electrical machine can be realized in a simple and cost-effective manner is to be provided.
This and other objects are achieved by a cooling arrangement which, according to the invention, comprises a support element on the electrical machine, and a cooling element on the engine block. At least a region of the electrical machine is connected to the cooling element of the engine block via the support element such that heat generated during operation of the electrical machine is dissipated or can be dissipated thermally into the engine block.
Such a cooling arrangement can be realized in a simple and cost-effective manner. The basic idea of the present invention lies in the fact that the electrical machine is thermally connected to the engine block. This thermal connection is effected via the support element and the cooling element. In this case, the heat loss produced in the electrical machine is dissipated into the engine block via the support element, which is preferably an integral part of the electrical machine. The secondary units, such as heat exchangers, pumps or the like, previously required for the cooling of the electrical machine may also be dispensed with. Furthermore, the prior requisite separate cooling of the casing of tile electrical machine is also dispensed with.
The engine for the vehicle may be a conventional internal combustion engine, which, depending on tile embodiment, has a one-piece or multi-piece engine block. The present invention is not restricted to special engine types, since cooling is effected only via the support element of the electrical machine and the cooling element of the engine block, and these two components, depending on the application, may be of any desired design. The only precondition is that good heat transfer between the two elements is ensured.
The electrical machines used may be, for example, synchronous machines and here, in particular, permanent-field synchronous machines. A machine especially worth mentioning is, for example, the starter-generator for vehicles. This is an electrical machine whose rotors are mounted via a crankshaft bearing arrangement of the internal combustion engine. The starter-generator is not only used for starting and stopping the engine but may also perform various functions during the engine operation, such as, for example, braking functions, booster functions, battery management, active vibration damping, synchronization of the internal combustion engine or the like.
Such a starter-generator is designed, for example, as an external-rotor synchronous machine and is connected to the engine block of the internal combustion engine via a stator support as support element. Such machines are especially suited for the heat-conduction cooling according to the invention, since the heat loss inside the machine can be dissipated therefrom directly into the engine block in a simple manner via the stator support and the cooling element of the engine block.
At least a region of the end face of the support element can advantageously bear flat against the end face of the cooling element and essentially free of gaps. Good heat transfer is thereby provided between the cooling element and the support element, resulting in a further improvement of the dissipation of the heat loss produced in the electrical machine into the engine block. To enlarge the surface provided for the thermal transfer, the end face of the support element and/or of the cooling element may of course also be designed such that it is not flat.
In a further embodiment, the cooling element may be provided on an end face of the engine block. In this case, the cooling element is advantageously designed such that good heat transfer is ensured. In principle, both end faces of the engine block are possible for the arrangement of the cooling element. However, the cooling element is preferably arranged on that end face of the engine block which faces the transmission. Furthermore, it is also possible for the electrical machine to be fastened to the cooling element via the support element.
The cooling element may also be designed, for example, as an integral section of the engine block. As a result, the cooling element may be produced directly along with the engine block in one operation during the manufacture of the engine block—for instance by a casting process, a factor which constitutes a solution which is simple in terms of design and is cost-effective.
However, it is also conceivable for the cooling element to first of all be produced as a separate component and to then be connected to the engine block. With such a solution, a, material having especially pronounced heat-conduction properties could be used, for example, for the cooling element. This would result in the heat transfer between the electrical machine and the engine block being further improved. Such a separately produced cooling element may be suitably connected to the engine block in a detachable manner or by cohesive bonding. Examples of advantageous types of connection are, inter alia, welded connections, screwed connections or the like. In particular in the case of a screwed connection, the cooling element may be additionally positioned via mating pins, mating sleeves or a centering diameter.
Since the end face of the engine block generally has a number of webs, projections, bulges and the like, which extend outward from the end face of the engine block, the cooling element is preferably of a height which approximately corresponds to the height of the elements described above. The cooling element may of course be of a different height.
In a further embodiment, the cooling element may be design as a ring element. The cooling element designed in such a way is preferably arranged concentrically around the crankshaft of the
Bauch-Panetzky Dieter
Demont Stefan
Weimer Jürgen
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
Perez Guillermo
Ramirez Nestor
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