Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-06-05
2001-05-01
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S256000, C310S089000, C310S216006
Reexamination Certificate
active
06225722
ABSTRACT:
PRIOR ART
The invention is based on an electric machine, in particular an electric motor, which has a rotor that rotates around a stator.
The references U.S. Pat. No. 4,337,491 A, U.S. Pat. No. 5,220,227 A, EP 0 236 467 B1, EP 0 433 479 A1, and DE 41 22 529 A1 have disclosed well-known machines which have a stator, a rotor that rotates around the stator, a rotor shaft that is supported so that the rotor shaft can rotate centrally in relation to the stator, rotor shaft bearing means, a base plate aligned crosswise in relation to the rotor shaft and thereby adjacent to the stator, and a supporting means that protrudes from the base plate in order to support the stator and the at least one rotor shaft bearing means. The supporting means is respectively comprised after the fashion of a tubular element that protrudes from the base plate, has the respective stator slid onto it, and has the respective rotor shaft bearing means built into it. Depending on whether the base plate is cast or is pressed out of sheet metal, the respective tubular supporting means can be cast in one piece with the base plate, or can be flange-mounted onto the respective base plate in the form of a relatively thin-walled tube and secured there by means of screws or press-fitted into a receiving bore disposed in the base plate. Clearly, the tubular supporting means must be precisely manufactured both externally and internally in order to both support the stators and contain the rotor shaft bearing means in a vibrationally secure manner. In this connection, the stators are made up of layers of stamped sheet metal cutouts and have an opening on the inside which is adapted to the tubular supporting means. Around an opening of this kind, the stamped sheet metal cutouts function as a stationary hub with stator pole teeth extending radially outward from the hub. For example, each stator pole tooth can carry an excitation winding or, according to EP 0 433 479 A1 and DE 41 22 529 A1, half as many excitation coils as stator pole teeth can be provided so that as can be clearly inferred from EP 0 433 479 A1, there can be a pole tooth with no winding between each pair of pole teeth that carry excitation coils. The rotor shaft bearing means are comprised of pairs of ball bearings, pairs of externally cylindrical slide bearing bushes, pairs of externally dome-shaped slide bearing bushes, or a single tubular bearing bushing that is embodied as elongated. The rotors contain permanently magnetized components in essentially cup-like component holders. These component holders are also referred to as pole cups.
ADVANTAGES OF THE INVENTION
The electric machine according to the invention includes a rotor that rotates around a stator and has an the advantage that a vibrational damping is achieved in a simple manner since half of the stator pole teeth are fastened to the base plate and as a result, these stator pole teeth are vibrationally damped and a central supporting tube, which according to the prior art protrudes from the base plate, is superfluous. The vibrationally damped stator pole teeth produce less radiation of noise than freestanding stator pole teeth from the prior art.
Advantageous improvements and updates of the electric machine are possible through the measures taken hereinafter.
The features set forth produce a reasonably priced base plate that can be manufactured out of sheet metal and has supporting means.
The features also produce a suitable exemplary embodiment, in particular for the use of a base plate made of sheet metal.
Further, the features set forth produce an advantage that magnetic flux through the stator pole teeth does not permit the production of eddy currents, which start from the stator pole teeth, pass through the base plate, and travel back to the stator pole teeth. The prevention of these eddy currents prevents the unnecessary consumption of electrical energy.
Other features produce a reasonably priced construction for supporting the armature shaft, in particular when the electric machine is a so-called small-power motor. If the tube is sintered out of bearing metal, another advantage is comprised in that a relatively greater store of lubricant can be built into the electric machine without otherwise conventional auxiliary means such as felt inserts.
Still further features achieve the advantage that if the stator is built into the base plate, an axially precise alignment takes place rapidly so that after this, only the rotational alignment of the stator in relation to the base plate has to be carried out.
REFERENCES:
patent: 5461271 (1995-10-01), Asama et al.
patent: 5578883 (1996-11-01), Sakashita et al.
patent: 5747908 (1998-05-01), Saneshige et al.
Knoepfel Gerd
Rupp Bernhard
Greigg Edwin E.
Greigg Ronald E.
Lam Thanh
Ramirez Nestor
Robert & Bosch GmbH
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