Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-05-03
2002-04-09
Waks, Joseph (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
Reexamination Certificate
active
06369473
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stator for an electrical machine including a plurality of stator coils arranged on a stator yoke and an interconnection arrangement arranged on one end face of the stator yoke having connecting conductors which are electrically insulated from one another and arranged concentrically with respect to one another. Each connecting conductor has a different diameter. The connecting conductors have connections for connection to the ends of the stator coils and for connection to the electrical machine. The present invention also relates to a method for producing such a stator.
2. Description of the Related Art
Stators for electrical machines generally have a plurality of stator teeth on which stator coils are wound. The coils are associated with individual phases of electrical power. The coils associated with a common phase are interconnected. In a three-phase machine the stator has three phases. Each of the phases have current applied to them separated by phase angles of 120°. The current input and the current output from the individual coils are passed out of the electrical machine at one stator end.
In known stators, the individual coils are interconnected by hand. In doing so, the individual coil ends of each coil were routed to the respective connections for connection to the electrical machine and electrically connected there. However, this type of interconnection has a number of disadvantages. For example, the separate interconnection of the individual coils to the corresponding connections for connection to the electrical machine results in thick cable harnesses which add to the space requirements of the electric machine. Space requirements are becoming more important in many applications. For example, a stator of the above-described type intended to be used in a vehicle is limited to the amount of area available in the engine compartment. Accordingly, efforts are being made to design individual components used in the engine compartment to be as small and space-saving as possible.
Furthermore, the known method of connecting individual coils requires that the individual wires of the coil ends be carefully insulated from one another. This requirement necessitates the use of additional insulation material and thus leads to a further increase in the required physical space. Finally, there is also a risk that faults can occur when the coil ends are being associated and correspondingly interconnected. Owing to the large number of wires, it is difficult to determine when a coil has been incorrectly connected, and when this situation occurs, which of the coils has been incorrectly connected. If a short circuit occurs in the interconnection arrangement, it is difficult and time consuming to locate the defect point.
Furthermore, the known interconnection arrangement is also highly costly, since the interconnection process must be carried out by hand. Automation of the process for production of such interconnection arrangements is impossible, so that the known interconnection arrangements are not suitable for large-scale production.
A known stator for electrical machines is disclosed in the preamble of claim
1
in the German reference DE 195 44 830 A1. In this stator, there is no individual interconnection of the respective coils to the connections for connection to the electrical machine. Instead, connecting conductors designed as ring conductors are proposed which are electrically insulated from one another and are arranged concentrically in an insulating slot structure and with a different diameter. The individual coil ends are connected via projections to the connecting conductors, with the projections projecting out of the interconnection arrangement body. This known stator avoids the complex individual interconnection of the individual coils, but this stator also has a number of disadvantages.
For example, this stator as well requires a relatively large amount of area because the interconnection arrangement is arranged in front of the coils in the axial direction. Furthermore, the projections provided for connection of the coil ends to the connecting conductors are aligned in a rigid manner at right angles to the connecting conductors which increases the area requirement for the interconnection arrangement and thus for the entire stator.
Another electrical machine having a stator provided with coils and connecting elements in the form of a ring provided for interconnection of the coils is disclosed in German reference DE 196 47 559 A1. These connecting elements designed in the form of a ring are arranged radially or axially adjacent and are electrically insulated from one another. The connection of the individual coil ends to the connecting conductors is made via openings formed in the conductors. The coil ends are passed through the openings and are then attached. This solution also still requires a relatively large amount of area, since the interconnection arrangement is once again arranged in front of the coils in the axial direction.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a stator for an electrical machine that avoids the problems of the prior art. More specifically, it is an object of the present invention to provide a stator for an electrical machine, in which the production of the individual components and the process of interconnecting the coils may be automated and carried out cost-effectively. Furthermore, the stator is intended to be designed to be particularly space-saving. In particular, the losses which occur in the stator are also intended to be minimized. Furthermore, an appropriately improved method for producing a stator is intended to be provided.
The object of the present invention is achieved by a stator comprising an interconnection arrangement arranged radially inside an area bounded by the stator coils. The connections for the ends of the stator coils comprise connection projections designed such that they project outward to attach the stator coil ends at an angle to the respective connecting conductor. Furthermore, a plurality of cutouts are provided in the interconnection arrangement for the connection projections, into which cutouts the connection projections may be bent or are bent.
The stator according to the present invention allows automatic production of the interconnection arrangement in a simple and cost-effective manner and allows automatic interconnection of the individual coils. At the same time, the area required for the interconnection arrangement, and thus for the entire stator, is considerably reduced compared to the prior art.
A fundamental idea of the present invention is that the stator coils are first fitted to the stator yoke. The connecting conductors are then introduced into the area which is bounded by the stator coils. The connecting conductors have a diameter which is smaller than the diameter of the surface bounded by the coils. Accordingly, the individual connecting conductors are no longer located axially in front of the coils, or their end windings, as has been described with respect to the known solutions. In fact, the connecting conductors are now arranged coaxially with respect to the stator coils, underneath or inside them. The individual connecting conductors preferably have a width which is matched to the end windings of the individual coils, so that the connecting conductors do not project beyond the coils, either in the axial or in the radial direction. The stator thus has a width which is governed only by the coil geometry.
The ends of each of the coils are attached to the connection projections on the connecting conductors. To accommodate this connection, the connection projections are designed such that they initially project at an angle, preferably at an angle of 90°, to the respective connecting conductor. This enables a simple connection of the coil ends to the connection projections.
Once the coil ends have been attached, the connection projections are bent into appropriate cutouts prov
Bauch-Panetzky Dieter
Baumeister Jens
Grau Edmund
Krause Peter
Ochs Martin
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
Waks Joseph
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