Electromagneto-mechanical converter

Details Electromagneto-mechanical converter Electromagneto-mechanical converter

2001-02-26

2002-11-26

Ramirez, Nestor (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S256000

Reexamination Certificate

active

06486583

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to all electromagneto-mechanical converter having a number of winding teeth composed of a material which is suitable for carrying a magnetic flux of a magnetic circuit. The winding teeth each have a winding supporting element for holding a winding and an attachment region which is intended for attaching the winding tooth to a yoke of the electromagneto-mechanical converter.
2. Description of the Related Art
Electromagneto-mechanical converters are rotating electrical machines which, using a magnetic field, can either convert electrical energy into mechanical energy using the motor principle, or can convert mechanical energy into electrical energy using the generator principle.
Electrical machines such as these, which may, for example, be in the form of synchronous machines or asynchronous machines, have a stationary part, which is called the stator, and a rotating part, which is called the rotor. Depending on the configuration of the electrical machine, the stator and the rotor are generally composed of a laminated core which is formed from a yoke and a number of winding teeth. An electrical winding (coil) is arranged in the slots between these winding teeth. When a current flows trough these windings, it produces a magnetic field in the electrical machine.
The windings are associated with individual winding sections, with the windings that are associated with a common winding section being connected to one another. In the case of a three-phase machine, there are a total of m winding sections, to each of which current is applied with a phase offset of 360°/m.
The laminated core with its electromagnetic components is generally referred to as a magnetic circuit. In the already known, conventional magnetic circuit configurations, the laminated cores which carry the windings are frequently integral. This means that the yoke and the winding teeth are in the form of a single component. However, this configuration of the laminated core has a number of disadvantages. Firstly, the laminated core itself can be produced only with a high level of structural complexity. Furthermore, it is difficult to insert the windings in the slots. In addition, there is a serious disadvantage in that it is impossible to use a preferred direction for the magnetic flux in the winding teeth since the magnetic circuit is produced either as a complete section or in segments (60° elements).
Magnetic circuit configurations are also known in which the laminated cores are in two pieces. This means that both the yoke and the individual winding teeth are first of all manufactured as separate components, and are then joined together to form a single, common laminated core. In the known solutions, winding teeth are connected to the yoke, for example, by means of a screw connection or a dovetail joint. Even though, with this solution, the windings can be fit to the winding teeth considerably more easily than in the case of integral solutions, the known two-piece laminated cores also have a number of disadvantages. For example, in production-engineering terms, it is complex to connect the winding teeth to the yoke via a screw connection or a dovetail joint.
For example, when using a dovetail joint, the winding teeth generally have specially designed keyways which are inserted at the side into correspondingly designed slots in the yoke Owing to the fact that the winding tooth is formed from a number of individual elements, side insertion for the dovetail solution results in sliding tracks, however, which produce undesirable electrical connections in the winding tooth, leading to losses, for example eddy current losses.
Furthermore, the known solutions often comprise components generally rotors) which do not carry an alternating flux and are thus in the form of massy components.
In order to allow electromagneto-mechanical converters of the said type to be operated in a particularly advantageous manner, it is necessary to be able to transfer the magnetic flux through the winding teeth to the yoke as completely as possible, and as far as possible without losses. However, this is feasible only with limitations with any of the solutions which have been described above and are known from the prior art.
DE 197 57 136, to which WO99/33157 corresponds, discloses an electromagneto-mechanical converter of this generic type whose winding teeth have a tooth head, a winding supporting element and an attachment region immediately adjacent to it. The yoke and winding teeth are composed of stamped laminates. The outer boundary of the attachment region of the winding teeth and the corresponding attachment region of the yoke have a dovetail-like contour. The winding teeth are connected to the yoke by being pushed in in the axial direction of the annular yoke. Furthermore, the boundary surface between the winding teeth and the yoke has an air gap in places. A disadvantage of this solution is that winding teeth and the yoke are damaged in the region of the boundary surface due to the inadvertent production of a short-circuit, as already stated further above, which prevents the magnetic flux from passing from the winding teeth to the yoke without losses. The magnetic flux (which is cried in the radial direction with respect to the yoke) in the winding region passes directly into the attachment region, and from there to the yoke. In the process, the magnetic lines of force necessarily cross over the attachment region (which is damaged by the stamping process) of the winding tooth and yoke, which males it considerably more difficult for the lines of force to make this transition. In this respect, the air gap which is formed in places on the boundary surface also has a negative effect.
The teaching in DE 196 43 561, to which WO98/18189 corresponds, refers to an electrical machine which is not of this generic type but has a single-pole winding, in which individual segments carry the magnetic flux mainly in the radial direction of the electrical machine, and in which the segments are advantageously produced from oriented-grain magnetic sheet steel. This solution has no yoke to produce a mechanical connection to the individual poles and to carry the magnetic flux. Instead of this, segments, some of which are of different designs, engage in one another alternately and support one another. However, this solution also involves the problem that the magnetic flux has to cross over the attachment regions of the individual poles directly.
SUMMARY OF THE INVENTION
The invention has the object of allowing the magnetic flux to pass from the winding tooth to the yoke as completely as possible and with as few losses as possible. Furthermore, it is intended to fix the winding tooth, which may have been provided with a winding in advance, to or in the yoke in a simple and cost-effective manner
According to the present invention, the object is achieved by an electromagneto-mechanical converter whose winding teeth have a transitional element which tapers from the winding supporting element to the attachment region and is immediately adjacent to the yoke of the electromagneto-mechanical converter. The attachment region has a magnetic reluctance which is greater than that of the winding supporting element and the transitional element owing to a change in the grain structure of the material, so that the magnetic flux which enters the transitional element from the winding supporting element is substantially passed from the transitional element into the yoke, and the attachment region is substantially free of magnetic flux.
Accordingly, the idea on which the invention is based is to physically separate the functions carried out by a winding tooth, namely carrying a magnetic flux, and the production of a mechanical connection to a yoke.
Thus, in the winding tooth, the magnetic flux is carried virtually exclusively by the winding supporting element and by the tapering transitional element, which extends from the winding supporting element to the attachment region. The winding supportin

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