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
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF INVENTION
Casing for motors with Metal-Polymer skeleton structure
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Jain Gaurav of M/S. Upkar Agencies, Varni Colony, Sagar, Madhya Pradesh - 470002, India and Joshi Sachin Sharad of Crompton Greaves Ltd, Industrial Design Centre, C G Global R&D Centre, Kanjurmarg (E), Mumbai - 400042 Maharashtra, India; both Indian Nationals.
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

Field of the Invention:
This invention relates to the field of motors.
Particularly, this invention relates to a casing for motors.
Background of the Invention:
Motors are devices which convert electrical energy to mechanical energy. In this process, a lot of heat is generated, and the motor housing heats up. There is a need for efficient dissipation of this heat. Dissipation of heat ensures longer motor life and eliminates stress from the motor housing. Also, it averts danger due to accidental contact with a heated motor housing.
There is a constant struggle for increasing the heat dissipating mechanisms and for reducing weight of the products to achieve sustainability. Various inventions have been made as seen in the prior art.
A motor casing typically includes a metal casing and fins extending thereto, according a general embodiment.
Prior Art:
DE8915212 discloses an electric machine, for example a three-phase generator for a motor vehicle, has a surface-cooled stator. It discloses metal and plastic coatings on a stator for purposes of heat dissipation is

disclosed, herein. However, there is a need for a heat dissipating motor casing with weight reduction of the motor.
US6557523 discloses an insert molded actuated motor.
JP10285859 disclose a motor. Insert molding is performed with resin so as to integrally cover all of a plurality of terminals to propose a small-sized stepping motor of high durability
All of the above patent document relate to fins of the motor and not towards the entire motor casing including the body and the fins. There is a need for an equal or better heat dissipating mechanism with reduced weight of total motor.
Objects of the Invention:
An object of the invention is to provide efficient heat dissipation from a motor.
Another object of the invention is to reducing the total cost of a motor.
Yet another object of the invention is to reduce the weight of a motor.
Still another object of the invention is to enhance the appearance of the existing motor.

Summary of the Invention:
According to this invention, there is provided a casing for motors, said casing comprises:
a. an annular metal sheet adapted to include a plurality of folds of
sheet, orthogonal to the sheet, protruding out of said annular sheet
adapted to define fins, with each pair of adjacent fins spaced apart
from each other in an equidistant fashion, and each said fold of
sheet including a gap in between the folds of each fin; and
b. plastic adapted to be insert molded in the gaps between each pair of
fins, thereby overlapping the annular metal sheet of the motor.
Typically, said fins include vertical ribs for providing support,
Preferably, said sheet is an aluminum sheet.
Typically, said sheet is a corrugated sheet.
Brief Description of the Accompanying Drawings:
Figure 1 illustrates a schematic of a motor according to the prior art.
The invention will now be described in relation to the accompanying drawings, in which:
Figures 2 and 3 illustrate a schematic isometric view of the motor.

Detailed Description of the Accompanying Drawings:
Figure 1 illustrates a schematic of a motor (50) according to the prior art.
According to this invention, there is provided a casing for motors with better heat dissipation.
Preferably, the motor disclosed herein is a squirrel cage motor. It is most commonly used product with domestic water pumping application and is generally placed inside the home or in the compound of the home for water pumping applications.
Figures 2 and 3 illustrate a schematic isometric view of the motor (100).
Preferably, the motor disclosed herein is a squirrel cage motor.
In accordance with an embodiment of this invention, there is provided an annular metal sheet (12) adapted to include a plurality of folds (14) of sheet, orthogonal to the sheet, protruding out of said annular sheet adapted to define fins (14). Typically, each pair of adjacent fins is spaced apart from each other in an equidistant fashion.
In accordance with another embodiment of this invention, said fold of sheet includes a gap (16) in between the folds of each fin.
Preferably, the fins include vertical ribs (18) for providing support.
Reference number 22 refers to a shaft of the motor. Reference number 24 refers to a stator of the motor.

Reference number 26 refers to windings of the motor.
The sheet may be aluminum sheet.
In accordance with yet another embodiment of this invention there is provided plastic (19) adapted to be insert molded in the gaps between each pair of fins, thereby overlapping the annular metal sheet of the motor, keeping the metal exposed from the inner side so as to be contact with stator of the motor, to have better heat dissipation.
The stator of the motor is wrapped with required thickness of sheet of metal with corrugation and required thickness and length of fins to support heat dissipation. The arrangement of sheet metal with fins act as a frame over which the suitable graded plastic is insert molded, thus acting as a casing for the motor.
The above idea of making the casing for the motor can be fitted with plastic end shields with end to end connection.
According to an exemplary embodiment of the motor casing of the prior
art, the following calculations were made in order to obtain exposed
surface are for heat dissipation.
Outer diameter of cylinder = 9 cm, Length of cylinder = 11.5 cm
Surface area of cylinder = 9*11.5*3.14 = 325 cm
Fin length = 10 cm, Fin height = 1 cm
No. of fins = 30 nos. and 2 faces.
Total surface area of fins = 10*1*30*2 = 600 cm2
Thus, total exposed surface area of prior art is 600+325 = 925 cm2

According to a similar exemplary embodiment of the motor casing of the
current invention, the following calculations were made in order to obtain
exposed surface are for heat dissipation.
No. of fins = 16
Exposed Outer surface area of fins = 3*10 = 30 cm2
Total outer surface area of fins = 30*16 = 480 cm2
Exposed Inner surface area of fins = 3.5*10 = 35 cm2
Total Inner surface area of fins = 35*16 = 560 cm2
Thus, total exposed surface area of invention is 480+560 = 1040 cm2
Thus, exposed surface area by proposed design is increased by 11.24 %. As exposed surface area is increased by 11%, thus heat deficiency, efficiency of the motor is increased by 11%.
According to an exemplary embodiment of this invention, the weight of the new motor is reduced by about a minimum of 40%, as the entire metal (i.e. aluminum) and die casted iron is replaced by polymer.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. A casing for motors, said casing comprising:
a. an annular metal sheet adapted to include a plurality of folds of
sheet, orthogonal to the sheet, protruding out of said annular sheet
adapted to define fins, with each pair of adjacent fins spaced apart
from each other in an equidistant fashion, and each said fold of
sheet including a gap in between the folds of each fin; and
b. plastic adapted to be insert molded in the gaps between each pair of
fins, thereby overlapping the annular metal sheet of the motor.
2. A casing as claimed in claim 1 wherein, said fms include vertical ribs for providing support.
3. A casing as claimed in claim 1 wherein, said sheet is an aluminum sheet.
4. A casing as claimed in claim 1 wherein, said sheet is a corrugated sheet.