Title of Invention

" A STATOR FOR AN ELECTRIC CEILING FAN MOTOR"

Abstract

This invention relates to a stator (1) for an electric motor for use in a ceiling fan comprising a stator core (4) extending outwardly from a centrally located hub (3), said core extending into the teeth (5) of the stator stack (2), characterising in that said stator stack (2) is provided with a central hole (8) made by punching, the said hole (8) generates the material requirement of producing stampings of another motor without affecting the performance of the motor as stated above.

Full Text

- 2 - FIELD OF INVENTION: This invention relates to an elecric ceiling fan motor-, and in particular to a stator provided in such a motor. The stator of the present invention has an advantageous application in a motor for use in an electric fan. However, the invention is not limited to such a particular application in that the stator may be employed in a motor for any other application. Thus, the reference to an electric ceiling fan is only by way of an exemplary embodiment, BACKGROUND OF INVENTION: In the known construction of electric ceiling fans, the motor comprises a stator consisting of a plurality of stampings held by rivets and a stationary shaft. The motor shaft is press fitted through a knurling to the stator. The motor further comprises a squirrel cage rotor consisting of stampings and duly pressure diecast aluminium rings. Reference is made in particular to the ceiling fan, stator of the known art, as the improvements envisaged by the present invention are essentially directed to such stator. As known in the art, such stator comprises a core extending from the hub for holding the motor shaft. The core extends into a plurality of teeth or poles disposed in a spaced relationship to each other and having the excitation of stator windings. The core normally consisted of a solid section of core material - 3 - Extending from the hub to the teeth. In certain known constructions, cooling slots are provided in the core section of the stator. The term 'Hub' in this case has been used for explanation purpose only. Actually in this case, it is an integral part of stator core. However, it has now struck to the inventor that the solid section normally employed in the stator core (4) is no longer necessary. A solid material of the core results in a substantial wastage of the material. Such a wastage is more distinct as the total ampere turns consumed in the electromagnetic flux path in the stator core is minimal. In feet, the air gap consumes most of the ampere turns, and in certain instances upto nearly 94% whereas only upto 1.5% is consumed by the stator core. Accordingly, it has now been found that the known construction of stators had a core with material which constituted a substantial waste and did not assist in the performance of the motor. OBJECTS OF THE INVENTION An object of this invention is to propose an improved construction of a stator for use in an electric motor. Another object of this invention is to propose a stator having a core with a reduced solid section. Still another object of this invention is to propose a stator having a core with a reduced solid section which minimizes on the use of material. Further objects and advantages of this invention will be more apparent from the ensuing descriptioa - 4 - At the outset of the description which follows, it is to be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only an exemplary embodiment, and without intending to imply any limitation on the scope of this invention. Accordingly, the description is to be understood as an exemplary embodiment and reading of the invention is not intended to be taken restrictively. According to the invention there is provided a stator for an electric ceiling fan motor comprising a stator core extending outwardly from a centrally located hub, said core extending into the teeth of the stator stack, characterising in that said stator stack is provided with a central hole made by punching, the said hole generates the material requirement of producing stampings of another motor without affecting the performance of the motor as stated above. BRIEF DESCRIPTION OF INVENTION : With reference to drawings in which Fig. 1 is tire elevational view of the stator according to die invention Fig. 2 represents plan view of the stator showing the punched hole according To the invention generating plan to additional motor with stampings Fig. 3 represents a view of the stator showing the hub of the stator Fig. 4 represents the elevational view of stator of prior art Fig. 5 represents the plan view of stator core arrangement of prior art According to this invention there is provided a stator (1) for use in an electric ceiling fan motor comprising a stator core (4) extending outwardly from a centrally located hub (3), said core extending into the teeth (5) of the stator stack (2). It is known that the stator core (4) constitutes one of the paths of the electromagnetic flux. However, it has now been surprisingly found that the solid section normally employed in the stator (4) core is no longer necessary. Further, the presence of a solid section, other than contributing strength to the stator does not substantially improve the electrical performance of the stator stack (2). - 5 - In accordance with this invention, the core (4) of the stator stack (2) is no longer of solid section, and whereby providing a substantial saving in the material. A consequential advantage is that the saved material may be employed for smaller motor cores. The increase in ampere turns and core loss in the stator of the present invention is negligible and as such that the performance levels are not affected. The stator core comprises a hub (3) for holding the motor shaft (6). The said hub (3) can be of different material with radial arms (7) extending outwardly terminating into the base of the stator stack (2). However, in such an embodiment, the core is no longer of a solid section but provided with a central hole (8) made by punching. In one such embodiment, the hub (3) may be of a suitable plastic having the required strength properties. In such an embodiment, the stator stack (2) stampings are loosely inserted into a mould and then integrally held with the plastic hub (3) during the process of moulding. An advantage of such a process is that the step of riveting is avoided. Further, the material taken out from the solid section can be used for making stampings of small size motors. In accordance with another embodiment of this invention the shaft (9) may also be made integral with the hub (3) and made of plastic with or without a metallic reinforcement e.g. a steel tube (10) insert disposed therein. - 6 - WE CLAIM 1. A stator (1) for an electric ceiling fen motor comprising a stator core (4) extending outwardly from a centrally located hub (3), said core extending into the teeth (S) of the stator stack (2), characterising in that said stator stack (2) is provided with a central hole (8) made by punching, the said hole (8) generates the material requirement of producing stampings of another motor without affecting the performance of the motor as stated above. 2. Hie stator (1) as claimed in claim 1, wherein the shaft (9) is made integral with said hub (3), said shaft (9) being made of plastic with or without metallic reinforcement e.g. a steel tube (10) insert disposed therein. 3. Hie stator as herein above described and illustrated with the accompanying drawings. This invention relates to a stator (1) for an electric motor for use in a ceiling fan comprising a stator core (4) extending outwardly from a centrally located hub (3), said core extending into the teeth (5) of the stator stack (2), characterising in that said stator stack (2) is provided with a central hole (8) made by punching, the said hole (8) generates the material requirement of producing stampings of another motor without affecting the performance of the motor as stated above.

Documents:

00366-cal-1999-abstract.pdf

00366-cal-1999-claims.pdf

00366-cal-1999-correspondence.pdf

00366-cal-1999-description(complete).pdf

00366-cal-1999-description(provisional).pdf

00366-cal-1999-drawings.pdf

00366-cal-1999-form-1.pdf

00366-cal-1999-form-18.pdf

00366-cal-1999-form-2.pdf

00366-cal-1999-form-3.pdf

00366-cal-1999-form-5.pdf

00366-cal-1999-g.p.a.pdf

00366-cal-1999-letters patent.pdf

366-CAL-1999-FORM 15.pdf