DE9203432U1 - Electric direct current machine, in particular electric starter motor for motor vehicles - Google Patents

Description

Description

The present invention relates to an electric direct current machine, and in particular to an electric starter motor for motor vehicles, comprising a rotor and a stator which are arranged in a tubular, cylindrical housing made of metallic material.

In many designs of such electrical machines, and in particular of electric starter motors for motor vehicles, the housing is essentially formed by a metallic tube which is manufactured by means of various mechanical techniques and machining processes.

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Balanstrasse 55 ■ 8000 Munich 90 · Telephone (0 89) 40 30 24 · Fax (0 89) 49 66 27 · Telex 5 22 054 patd

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In order to provide such housings with sufficient protection against the effects of corrosive atmospheric influences, electrogalvanic treatment or various types of painting are usually used. Such treatments result in increased costs, require expensive equipment to carry them out and involve complex conversions and transportation of the parts.

In order to avoid the above-mentioned obvious disadvantages of the prior art, the object of the present invention to provide a better protected electric direct current machine, and in particular an electric starter motor of the type described above for motor vehicles, is achieved in that the housing is surrounded by a tubular casing element made of aluminum or aluminum alloys.

The ends of this cladding element can be easily bent open using a flanging or flattening process on the peripheral edges of the housing end.

Further features and advantages of the invention will become apparent from the following detailed description with reference to the accompanying drawings, which are given by way of example only and are not limiting.

Show it

Figure 1 is an elevational view, partly in section, of an electric starter motor for motor vehicles as constructed according to the invention, and

Figure 2 is a section on an enlarged scale of a feature indicated by reference number II in Figure 1.

In Figure 1, reference number 1 designates an electric starter motor for motor vehicles. The motor comprises a tubular cylindrical housing 2 made of metallic material in which a rotor 3 and a stator 4 are located.

The stator 4 comprises in particular a plurality of pole pieces 5 which are anchored to the inner surface of the housing by means of fastening screws 6. These screws 6 extend into openings or seats 7 which are provided in the wall of the housing 2 and are dimensioned such that the heads of the screws are countersunk in the housing when tightened.

In order to protect the outer surface of the housing 2 from external influences, for example atmospheric influences, the housing is surrounded by a tubular casing element 10, which consists of aluminum or aluminum alloys.

The casing element 10 can be manufactured using conventional technologies, for example by extrusion or drawing, and has a thickness of typically a few tenths of a millimeter. It is easily pulled onto the housing 2 after the field winding and the pole shoes 4 have been mounted.

The fastening of the casing element 10 to the housing 2 can be carried out by flattening the end peripheral edges of the housing 2, as shown at 11 in Figure 1. The fastening of the casing 10 to the housing 2 can be further improved, for example by pressing the casing in the areas which correspond to the countersunk seats 7 of the fastening screws 6 of the pole shoes, as shown at 12 in Figure 2.

The application of the cladding element 10 to the housing can be carried out automatically on assembly lines using industrial robots.

In addition to the protective function described above, the casing element 10 also has the function of dissipating the heat generated during operation of the electrical machine.

The solution described above therefore makes it possible to obtain effective protection of the casing without having to resort to the more expensive electro-galvanic treatment or painting processes. It also provides a better aesthetic result and more effective heat distribution.

Of course, the invention also extends to all embodiments that provide the same benefit based on the same inventive concept.

Claims (4)

Expectations 1. Electric direct current machine, in particular an electric starter motor (1) for motor vehicles, comprising a rotor (3) and a stator (4) which are arranged in a tubular, cylindrical housing (2) made of metallic material, characterized in that the housing (2) is surrounded by a tubular casing element (10) made of aluminum or its alloys. 2. Electrical machine according to claim 1, characterized in that the ends (11) of the cladding element (10) are bent or drawn in over the end peripheral edges of the housing (2). jst:si Balanstrasse 55 ■ 8000 Munich 90 · Telephone (0 89) 40 30 24 · Fax (0 89) 49 66 27 · Telex 5 22 054 patd 2 - 3. Electrical machine according to claim 1 or 2, wherein the stator (4) comprises pole pieces (5) anchored to the inner surface of the housing (2) by means of fastening parts (6) extending into openings or seats (7) provided in the wall of the housing (2) and designed so that these parts (6) are sunk in the respective seats (7) when tightened, characterized in that the above-mentioned casing element (10) is pressed corresponding to the seats (7) of the fastening parts (6). 4. Electrical machine according to one of the preceding claims, characterized in that the tubular casing element has a thickness between 0.1 and 1 mm.