Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1995-04-20
1998-02-03
Stephan, Steven L.
Electrical generator or motor structure
Dynamoelectric
Rotary
310179, 310214, 310215, 310216, 310254, 29596, 29598, H02K 112
Patent
active
057148279
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to a stator for an electric machine which includes a tubular unslotted ferromagnetic flux collector ring, and stator windings formed by a number of winding coils associated with the flux collector ring, wherein each of the winding coils has at least two legs which extend substantially axially along the inner cylindrical surface of the flux collector ring.
A problem concerned with previous electric machines of the above type is a relatively small effective space available for the winding coil wires in relation to the total cross sectional area of the windings within the flux collector ring. This means a relatively low efficiency of the machine.
One prior art method for arranging the stator windings inside a flux collector ring is described in EP 0 225 132 and comprises mounting of the winding coils on a support structure of a non-magnetisable, non-conductive material and insertion of the support structure and the windings together into the flux collector ring. In this known machine, the winding support structure and the takes a lot of space and reduces the effective space available for the winding coil wires.
Another prior art method for building electric machine stators, see for instance EP 0 193 929, comprises the measures of locating the winding legs by their end by using threads or tape, and then introducing them together with a fiberglass sleeve into the flux collector ring and fixing them to the later by injecting a resin material.
By this known method it is very difficult to obtain an accurate orientation of the winding wires and hence a high density packing of the latters.
Accordingly, the invention is intended to solve the problem of how to accomplish a stator for an electric machine with a maximum effective space available for the winding coil wires in relation to the total cross sectional area of the windings and at the same time obtain an accurate orientation of the winding coil wires inside the flux collector ring.
SUMMARY OF THE INVENTION
According to the present invention, a stator for an electric machine comprises a tubular slotless ferromagnetic flux collector ring (16), the flux collector ring having an inner cylindrical surface; and stator windings (17) including a number of winding coils (18, 19, 20) associated with the flux collector ring (16), each of the winding coils (18, 19, 20) having a number of wires put together in at least two winding legs (18a, b, 19a, b, 20a, b) extending substantially axially along the inner cylindrical surface of the flux collector ring (16). Each of the winding legs (18a, b, 19a, b, 20a, b) is confined in a tube-shaped envelope (22) of a thin, flexible, non-conductive non-magnetizable material which is impregnated and bonded together with the wires in each of the winding legs (18a, b, 19a, b, 20a, 20b) by a hot-setting resinous material. The winding coil legs are fixed and secured to the flux collector ring (16) as well as to one another by bonding with the hot-setting resinous material.
According to another aspect of the invention, a process for installing stator windings in a tubular slotless flux collector ring for an electric machine comprises arranging the windings in the coils, such that each coil has a number of wires put together in at least two legs; enclosing each coil leg in the thin-walled envelope of the thin, flexible, non-conductive non-magnetizable material; inserting all of the coil legs in the flux collector ring in a predetermined pattern; and inserting a mandrel to locate properly the coil legs relative to the flux collector ring. A hot-setting resinous material is applied inside as well as outside each envelope for bonding the respective coil leg to the envelope and for bonding the envelopes to each other and to the flux collector ring, to thereby form the stator.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention is described below in detail with reference at the accompanying drawing.
FIG. 1 shows an electric motor incorporating a stator according to the
REFERENCES:
patent: 2701316 (1955-02-01), Willits et al.
patent: 4703211 (1987-10-01), Yazaki et al.
patent: 4954739 (1990-09-01), Schultz et al.
patent: 5197180 (1993-03-01), Mihalko
patent: 5306976 (1994-04-01), Beckman
patent: 5313127 (1994-05-01), Danley et al.
patent: 5313131 (1994-05-01), Hibino et al.
Atlas Copco Tools AB
Enad Elvin G.
Stephan Steven L.
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