Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1996-08-19
1998-06-23
Dougherty, Thomas M.
Electrical generator or motor structure
Dynamoelectric
Rotary
310156, 310 83, 310261, H02K 710
Patent
active
057709041
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an electric motor with an integrated gear unit.
From DE-U-85 13 219 an electric motor designed as an external armature is known, in the core area of which a planetary gear unit with a sun gear shaft, a planet carrier and a hollow planetary gear are accommodated, with the hollow planetary gear encompassing the planetary gear unit. The external armature is fastened at the sun gear shaft which is supported in the stator by means of two ball bearings. The stator again is connected with the hollow gear of the planetary gear unit via connecting screws with the gear unit being fastened to a structural housing part.
From EP-A-O 463 895 an electric motor with an internal armature and an internal planetary gear unit is known, the sun gear shaft of which is supported in the stationary housing of the electric motor by means of a ball bearing.
The present invention is based on the object to provide an electric motor with the bearing method for its movable parts and its assembly being simplified. At the same time, the shortest possible installation length of the electric motor is to be achieved.
This is solved according to the invention by means of an electric motor with the characteristics indicated in claim 1 or claim 2. According to the invention the armature is supported in the hollow planetary gear by means of an armature bell-side bearing via the sun gear shaft, and the inner end of the sun gear shaft rotatably bears against the planet carrier by means of another bearing, with the planet carrier being rotatably supported in the hollow planetary gear by means of a bearing. This bearing method achieves a compact design and, in particular, a short installation length as well as a simple assembly of the electric motor according to the invention.
The gear unit which is implemented as a planetary gear with its sun gear shaft and its planet carrier has a hollow planetary gear which forms the housing of the gear unit so that the gear unit is completely encapsulated against the surrounding parts of the electric motor. Moreover, the bearing of the sun gear shaft in the interior of the gear unit can be arranged in alignment with the bearing of the planet carrier.
According to the invention, the hollow planetary gear is provided with a fastening means for a supporting plate holding the stator which is advantageous in that no separate supporting of the gear unit is required. Rather, the suspension of the motor and the gear unit is effected by one and the same component. The gear moment is thus immediately introduced into the motor suspension.
The supporting plate for the stator encompasses the hollow planetary gear in the area of one of its faces (the output side) annularly. The armature cage and the stator windings are arranged in the axial extension of the annular supporting plate.
According to the invention, the hollow planetary gear may also be integrally connected with a supporting plate for the stator. This makes any additional (fastening) components and installation steps unnecessary. Moreover, this integral configuration of the supporting plate with the hollow planetary gear acts as an enlarged cooling surface for the gear unit which is preferably encapsulated and immersed in gear oil.
In another embodiment the supporting plate for the stator is arranged and fastened in a recess of the hollow planetary gear which opens towards the edge side in the area of one of its faces.
In a preferred embodiment the sun gear shaft comprises a fastening means for the armature at its end portion which protrudes from the hollow planetary gear.
In this case, too, separate bearings of the armature and the sun gear shaft can be eliminated.
Due to the fact that the armature is supported via the sun gear shaft in the hollow planetary gear in at least one bearing (the support is preferably effected by several bearings), an additional support of the sun gear shaft together with the armature at the housing of the electric motor is not necessary. This also eliminates additional seals which would be required in t
REFERENCES:
patent: 2514460 (1950-07-01), Tucker
patent: 4274023 (1981-06-01), Lamprey
patent: 5019733 (1991-05-01), Kano et al.
Grundl Andreas
Hoffmann Bernhard
Rasch Reinhard
Dougherty Thomas M.
Grundl und Hoffman GmbH Gesellschaft fur elektrotechnische Entwi
Williams Timothy A.
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