Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2002-10-22
2004-03-16
Lam, Thanh (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S189000, C310S179000
Reexamination Certificate
active
06707186
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to a stator for an electric machine with a ring-shaped stator yoke at which a plurality of stator coils having coil ends are arranged, and with a wiring arrangement for the stator coils at a front side of the stator yoke, wherein the wiring arrangement has connection conductors which are electrically insulated relative to one another and are concentric to one another. The invention also relates to methods for producing a wiring arrangement of a stator.
2. Description of the Related Art
Known stators for electric machines have a stator yoke with a quantity of stator teeth which hold the electric winding, e.g., in the form of individual stator coils which are wound from an insulating wire. The ends of the coils are associated with individual strands and are wired together in a predetermined manner by shared connection conductors. In three-phase generators, the stator has three strands and, therefore, at least three connection conductors to which current is applied at a 120-degree phase offset. The connection conductors are fed to a switch box for connecting the electric machine to a source of electric power.
U.S. Pat. No. 6,369,473 discloses a stator for an electric machine in which the wiring arrangement has electrically insulated connection conductors allocated to each other in concentric manner (see
FIG. 7
of the present patent application). The terminals for the ends of the stator coils are formed at the connection conductors as terminal extensions projecting from the latter. The electrical connection can be carried out by a joining technique such as welding, soldering and/or simple winding around the terminal extensions. The connection conductors are supported mutually and at the stator by means of insulating center strips arranged therebetween.
In one of the joined connections mentioned above, it is disadvantageous that the process heat introduced for connecting can result in damage to the insulation between the connection conductors and, further, to the insulation of the wound wires in the area of the coils. This can lead very quickly to unwanted short circuiting which influences the operation of the electric machine and can even lead its outage. Further, damage to the insulation arranged between the connection conductors cancels the fixed position of the connection conductors, which are then no longer arranged at the stator in such a way that reliable operation is ensured. Vibrations which occur during the operation of the electric machine or which act on the latter from the outside lead to mechanical alternating loads on the electrical connections of the machine which can loosen within a short period of time. Winding around the terminal extensions is a typical manual work step which impedes increased efficiency in the manufacture of such stators. Because of the relatively large number of coil ends, there is a considerable risk of faulty connections in the wiring of the coils of a stator due to incorrect allocation to the connection conductors. Even when great caution is exercised in this regard, 100 percent certainty can not be achieved in the manufacture of stators.
SUMMARY OF THE INVENTION
It is the object of the present invention to improve a stator constructed in the manner described above in such a way that particularly its wiring arrangement is designed more simply and can be produced, at the same time, by safe processes and in an automated manner. In a further aspect of the invention, methods are provided for producing a wiring arrangement of a stator.
According to a first solution, the invention is based on the arrangement of receiving chambers at the stator which are suitable for mechanically fixing the connection conductors in position and for carrying out the electrical connections of the coil ends to the respective connection conductors. In this way, the assembly steps comprising mechanical fixation of the connection conductors and electrical connection of the latter to the coil ends, which were originally two independent assembly steps, are combined in one individual step so that considerable time and cost are saved in the production of the stator.
According to a second solution, the connection conductors are not connected directly to the coil ends; rather separate plug-in contacts are arranged between the coil ends and the connection conductors. In this way, individual coils can be checked for proper functioning before they are arranged at the stator, and defective coils can be excluded from the continued assembly process. This prefabrication by means of inexpensive and easily fitted plug-in contacts makes it possible to economize on manufacturing costs and manufacturing time and accordingly reduces the return of defective stators at the same time.
In an advantageous construction, the receiving chambers have receiving means for the coil ends. The coil ends can accordingly also be brought into a predetermined position for contacting at the receiving chamber. This step aims at high reproducibility of the electrical connection points between the coil ends and the connection conductors.
Assembly is further simplified in that the receiving chambers are arranged on partial circles which substantially correspond to those of the connection conductors. In this case, for example, a circular connection conductor can simply be attached to an axial side of the stator, wherein the terminals of the connection conductor are simultaneously introduced into the corresponding receiving chambers and a plurality of desired electric clamping connections are also produced simultaneously.
In a particularly advantageous further development, the terminals of the connection conductors are constructed as piercing or cutting clamps. In this way, a cutting clamp connection, known in electrical connection technology, is realized with respect to the coil ends. A particularly noteworthy advantage is that the cutting clamp displaces the insulating sleeve of the coil ends when producing the connection, which obviates any additional steps for removing the insulating sleeve. Accordingly, unintended removal of the insulation sleeve at unwanted locations is excluded.
In repairs, the use of reusable cutting clamps enables fast and simple detachment of the electrical connection, e.g., to a defective coil or damaged connection conductor.
The cutting clamps are advantageously fixed in the receiving chambers by locking elements, for which purpose the terminals of the connection conductors and/or the receiving chambers include barbs or spring elements. Accordingly, when placed on an axial side of the stator, the connection conductors enter into a self-locking mechanical connection with the stator, so that it is not necessary to use additional connections such as screw connections or rivet connections.
It is likewise advantageous when the plug-in contacts and/or the receiving chambers comprise locking elements in the form of barbs or spring elements.
The number of receiving chambers associated with a coil end advantageously corresponds to the quantity of connection conductors. This ensures that the wiring remains changeable, that is, the coil ends can enter into an electrical connection with all connection conductors depending on the applied wiring plan.
It has proven advisable to form the receiving chambers at the bobbins. In this way, a simple and fixed allocation of positions of the coil ends to the receiving chambers is achieved.
Following the concentric arrangement of the common connection conductors, it is likewise useful to arrange the receiving chambers associated with a coil end at the stator radially with respect to one another.
The electrical connection points of the coil ends with the terminals of the connection conductors are preferably arranged within the interior of open chambers formed by the receiving chambers for protection against external influences.
Similarly, the electrical connection points of the coil ends with the plug-in contacts are advantageously arranged in the interior of the chambers.
In an
Cohen & Pontani, Lieberman & Pavane
Lam Thanh
ZF Sachs AG
LandOfFree
Stator for an electric machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stator for an electric machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stator for an electric machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3261882