FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
PROVISIONAL SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Assembly fixture for pump motor assembly
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
Inventors
Sathe Mahesh Kashinath & K Guruprasad, both of Crompton Greaves Ltd, Industrial Design Centre, CG Global R&D Centre, Kanjur (E), Mumbai 400042, Maharashtra, India, both are Indian Nationals

PREAMBLE TO THE DESCRIPTION
The following specification describes the invention


This invention relates to a Bus Fan Motor with thrust bearing.
The present Bus Fan motor assemblies normally carry Fan blades made of plastic or metal integral with single phase electric motor stator and rotor hub again made of plastic of metal. Stator though encapsulated by hub is flot integral or fixed with hub, whereas the same is mounted on shaft integral with hub cover and shaft further getting located and fixed into bush or ball bearing embedded ()n the inner periphery of hub, allowing the hub along with fan blade and rotor sub assembly to rotate over the stator sub assembly mounted on the hub cover integral shaft. In such construction hub cover which is stationary normally carry the different fixing arrangement to mount the complete. fasv assembly w. bus wall of roof and ssstaMifc or plastic mesh ragt fa protecting fan blades.
Having bush or ball bearing reduces the cost of product but at the same time do not allow to have totally enclosed assembly of hub and hut? cover and some annular gap between hub inner periphery and hub cover outer periphery is always present which apart from just allowing free rotation of hub do not support any other function like bush or ball bearing (unsealed) lubrication or hub diameter reduction on hub cover side. Further maintenance of such a small gap between hub and hub cover peripheries with flexible thinner material of hub component with present manufacturing, assembly, servicing and maintenance techniques used is difficult and fan in long run is likely to make noise due to friction between hub & hub cover.
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An object of the invention is to provide a Bus Fan motor assembly which eliminates the hub and hub cover frictional noise by having rigid seating of hub at front and back end w. r. t. Stationary hub cover.
Another object of the invention is to provide a Bus Fan motor assembly which provides required ingress protection by having hub tight fitted onto thrust bearing outer racing eliminating flexible couple formation while fan tilting if provided on bus wall.
Another object of the invention is to provide a Bus Fan motor assembly which allows the lubrication of thrust bearing without removal of bus fan assembly from bus wall. Another object of the invention is to provide a Bus Fan motor assembly which improves the hub design with marginal increase in cost and imparts required strength to hub open end on hub cover side with optimum material thickness increase and almost encapsulating the thrust bearing one half outer races three faces and there by having improved seating for bearing.
According to the invention there is provided a Bus Fan motor assembly comprising an hub enclosure,hub enclosure fixing ring, thrust bearing and hub cover enclosing hub cover integral shaft, stator sub assembly mounted over it and rotor sub assembly seating on inner periphery of hub annular to stator outer periphery. Where hub enclosure having thrust bearing one half outer race size bearing seating face with hub getting almost press fitted over the thrust bearing which is further positively attached to thrust bearing by hub enclosure fixing ring and making the complete assembly totally enclosed. Almost similar construction is used for thrust bearing other half outer
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race fixing to hub cover for ensuring that the other half of the thrust bearing is rigid and stationary along with hub cover and shaft along with stator sub assembly integral with the same.
In accordance to the present invention, an Bus Fan motor assembly comprises an hub with fan blade integral enclosures thrust bearing, a hub cover having shaft and stator integral with the same and hub and hub cover fixing rings.
In accordance to the present invention, the hub enclosure comprises a single molded or sheet metal body enclosing accommodating and holding rotor subassembly and one half of the thrust bearing..
In accordance to the present invention, hub enclosure also encloses the hub cover integral shaft component carrying stator assembly over it.
In accordance to the present invention, to have completely stationary hub cover and other half of the thrust bearing there is hub cover holding ring which ensures the steadiness and rigidness of hub cover and other half of the thrust bearing.
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In accordance to the present invention, enclosure eliminates the motor fan cowl i.e. metallic fan enclosure which is normally a separate part in pump motor assembly.