FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 200S
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A multi drive electric motor
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR
Kamble Deepak Gajanan, Crompton Greaves Ltd, Enginering Group, CG Global R&D Centre, Kanjurmarg (East), Mumbai 400 042, Maharashtra, India, an Indian national
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 a multi drive electric motor.
BACKGROUND OF THE INVENTION
An electric motor generally comprises a single shaft and a single drive is taken from the motor shaft. An object of the invention is to provide a multi drive electric motor which makes optimal use of the magnetic fluxes generated in the motor so as to drive multiple shafts and give multiple drives. Another object of the invention is to provide a multi drive electric motor which drives multiple shafts and gives multiple drives and which is simple in construction and operation and is economical. Another object of the invention is to provide a multi drive electric motor which drives three shafts so as to give three drives. Another object of the invention is to provide a multi drive electric motor which drives four shafts so as to give four drives.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a multi drive electric motor comprising a housing formed of two end shields fitted together, a first shaft and a second shaft disposed in the housing in axially spaced apart relationship with each other, the first shaft being rotatably held in one end shield and protruding out of the said one end shield, a first rotor mounted on the first shaft and having a first set of rotor magnets mounted on the outer circumference thereof describing a gap with the inner circumference of a stator disposed over the first rotor in spaced apart relationship therewith and fitted in the

housing, the first rotor further comprising an angular projection projecting from one end face thereof, one limb of the angular projection being in spaced apart relationship with one end face of the stator and having a second set of rotor magnets mounted on the inner surface thereof describing a gap with the said one end face of the stator, a second rotor comprising a cup shaped portion disposed over the outer circumference of the stator in spaced apart relationship therewith and having a third set of rotor magnets mounted on the inner circumference thereof describing a gap with the outer circumference of the stator, the second rotor further comprising a third shaft extending over the second shaft in spaced apart relationship therewith and rotatably held in the other end shield, the third shaft protruding out of the other end shield, the second shaft being rotatably held in the third shaft and protruding out of the third shaft and a third rotor comprising a recessed portion formed at the inner end of the second shaft and rotatably held at the inner end of the first shaft, the third rotor further comprising a radial rim extending upto the other end face of the stator in spaced apart relationship therewith and having a fourth set of rotor magnets mounted at the inner surface thereof describing a gap with the other end face of the stator.
According to the invention there is also provided a multi drive electric motor comprising a housing formed of two end shields fitted together, a first shaft and a second shaft disposed in the housing in axially spaced apart relationship with each other, a first rotor mounted on the first shaft and having a first set of rotor magnets mounted on the outer circumference thereof describing a gap with the inner circumference of a stator disposed over the first rotor in spaced apart relationship therewith and fitted in the housing, a second rotor comprising a disc portion disposed in spaced apart relationship with one end face of the stator and having a second set of rotor magnets mounted thereon describing a

gap with the said one end face of the stator, the second rotor having a third shaft rotatably mounted in the one end shield and extending over the second shaft in spaced apart relationship therewith and protruding out of the one end enshield, the first shaft protruding out of the third shaft and being rotatably mounted in the third shaft, a third rotor comprising a cup shaped portion disposed over the outer circumference of the stator in spaced apart relationship therewith and having a third set of rotor magnets mounted on the inner circumference thereof describing a gap with the outer circumference of the stator, the third rotor further comprising a fourth shaft extending over the second shaft in spaced apart relationship therewith and being rotatably held in the other end shield, the fourth shaft protruding out of the other end shield, the second shaft being rotatably held in the fourth shaft and protruding out of the fourth shaft and a fourth rotor comprising a recessed portion formed at the inner end of the second shaft and rotatably held at the inner end of the first shaft, the fourth rotor further comprising a radial rim extending upto the other end face of the stator in spaced apart relationship therewith and having a fourth set of rotor magnets mounted at the inner surface thereof describing a gap with the other end face of the stator.
The following is a detailed description of the invention with reference to the accompanying drawings, in which;
Fig 1 is a crossectional view of a multi drive electric motor according to an embodiment of the invention; and
Fig 2 is a crossectional view of a multi drive electric motor according to another embodiment of the invention.

The multi drive electric motor 1A as illustrated in Fig 1 of the accompanying drawings comprises a housing 2 formed of two endshields 3 and 4 fitted together by screws 5. A first shaft 6 and a second shaft 7 are disposed in the housing in axially spaced apart relationship with each other. Shaft 6 is rotatably held in endshield 3 using bearing 8 and protrudes out of endshield 3. 9 is a first rotor having a first set of rotor magnets 10 mounted on the outer circumference thereof describing a gap (not marked) with the inner surface of a stator 11 disposed over rotor 9 in spaced apart relationship therewith and fitted to a bracket 12 which in turn is rigidly held between the endshields by screws 5. Rotor 9 further comprises an angular projection 13 projecting from one end face thereof. One limb 13a of angular projection 13 is disposed in spaced apart relationship with one end face of the stator and has a second set of rotor magnets 14 mounted on the inner surface thereof describing a gap (not shown) with the said one end face of the stator. 15 is a second rotor comprising a cup shaped portion 16 disposed over the outer circumference of the stator in spaced apart relationship therewith and having a third set of rotor magnets 17 mounted on the inner circumference thereof describing a gap (not shown) with the outer circumference of the stator. The second rotor further comprises a third shaft 18 extending over shaft 7 in spaced apart relationship therewith and rotatably held in endshield 4 using bearing 19. Shaft 18 protrudes out of endshield 4. Shaft 7 is rotatably held in shaft 18 using bearing 20 and protrudes out of shaft 18. 21 is a third rotor comprising a recessed portion 22 formed at the inner end of shaft 7 and rotatably held at the inner end of shaft 6 using bearing 23. Rotor 21 further comprises a rim 24 extending upto the other end face of the stator 11 in spaced apart relationship therewith and having a fourth set of rotor magnets 25 mounted at the inner surface thereof describing a gap with the other end face of the stator. 26 is a mounting bracket fixed to

the end shield 4. The motor is mounted on a rigid surface (not shown) with the help of bracket 26. 27 is a pulley mounted on the protruding end of shaft 18. During operation of the motor, magnetic fluxes generated at the outer circumference of the stator and at the said one end face of the stator corresponding to rotor magnets 10 and 14 drive rotor 9 and shaft 6. Magnetic fluxes generated at the outer circumference of the stator also drive rotor 15 and shaft 18. Magentic fluxes generated at the said other end face of the stator corresponding to rotor magnets 25 drive rotor 21 and shaft 7. Drive from shaft 18 is taken through pulley 27. According to the invention magnetic fluxes generated all around the stator are fully optimally used to generate maximum power and drive three shafts namely 6, 7 and 18 and drive is taken from the shafts to drive loads connected thereto.
The multi drive electric motor IB as illustrated in Fig 2 of the accompanying drawings comprises a housing 28 formed of two end shields 29 and 30 fitted together by screws 31. A first shaft 32 and a second shaft 33 are disposed in the housing in axially spaced apart relationship with each other. A first rotor 34 is mounted on shaft 32 and has a first set of rotor magnets 35 mounted on the outer circumference thereof describing a gap (not shown) with the inner circumference of a stator 36 disposed over rotor 34 in spaced apart relationship therewith and fitted to a bracket 37 held between the end shields and fitted to the end shields by screws 31. 38 is a second rotor comprising a disc 39 disposed in spaced apart relationship with one end face of the stator and having a second set of rotor magnets 40 mounted thereon describing a gap (not shown) with the said one end face of the stator. Rotor 38 comprises a third shaft 41 rotatably held in end shield 29 using bearing 42 and extending over shaft 32 in spaced apart relationship therewith and protruding out of end shield 29. Shaft 32 protrudes out of shaft 41 and is rotatably held in shaft 41 using bearings 43. 44 is a third rotor comprising a cup shaped portion 45

disposed over the outer circumference of the stator in spaced apart relationship therewith and having a third set of rotor magnets 46 mounted on the inner circumference thereof describing a gap (not shown) with the outer circumference of the stator. Rotor 44 further comprises a fourth shaft 47 extending over shaft 33 in spaced apart relationship therewith and rotatably held in end shield 30 using bearing 48. Shaft 47 protrudes out of endshield 30. Shaft 33 is rotatably held in shaft 47 using bearing 49 and protrudes out of the shaft 47. 50 is a fourth rotor comprising a recessed portion 51 formed at the inner end of shaft 33 and rotatably held at the inner end of shaft 32 using a bearing 52. Rotor 50 further comprises a radial rim 53 extending upto the other end face of the stator in spaced apart relationship therewith and having a fourth set of rotor magnets 54 mounted at the inner surface thereof describing a gap (not shown) with the other end face of the stator. 55 and 56 are pulleys mounted on shafts 41 and 47 respectively. 57 is a mounting bracket fitted to the end shield 30. Motor IB is mounted on a rigid surface (not shown) with the help of bracket 57. During operation of the motor magnetic fluxes generated at the outer circumference of stator 36 drives shafts 32 and 47. Magnetic fluxes generated at the one end face of the stator corresponding to rotor 38 drives shaft 41. Magnetic fluxes generated at the other end face of the stator corresponding to rotor 50 drives shaft 33. Magnetic fluxes generated all around the stator are thus fully optimally used for driving four shafts namely shaft 32, 33, 41 and 47. Drives from the respective shafts are taken to drive multiple loads connected thereto.
The embodiments of the multi drive electric motor as illustrated in Figs 1 and 2 are simple in construction and operation and are also economical in that multi drive is available from a single motor. Pulleys are optional and instead of pulleys, sprockets or other means can be used to take the drive from the respective shafts. The stator can be

mounted to the end shields or to the housing in a different manner. The invention is essentially in deriving multi drive from a single motor by fully optimally making use of the fluxes generated all around the stator. Variations in the configurations of the rotors and rotor shafts and stator for achieving the objects of the invention, which are obvious those skilled in the art are to be construed and understood to be within the scope of the invention.

We Claim:
1. A multi drive electric motor comprising a housing formed of two end shields fitted together, a first shaft and a second shaft disposed in the housing in axially spaced apart relationship with each other, the first shaft being rotatably held in one end shield and protruding out of the said one end shield, a first rotor mounted on the first shaft and having a first set of rotor magnets mounted on the outer circumference thereof describing a gap with the inner circumference of a stator disposed over the first rotor in spaced apart relationship therewith and fitted in the housing, the first rotor further comprising an angular projection projecting from one end face thereof, one limb of the angular projection being in spaced apart relationship with one end face of the stator and having a second set of rotor magnets mounted on the inner surface thereof describing a gap with the said one end face of the stator, a second rotor comprising a cup shaped portion disposed over the outer circumference of the stator in spaced apart relationship therewith and having a third set of rotor magnets mounted on the inner circumference thereof describing a gap with the outer circumference of the stator, the second rotor further comprising a third shaft extending over the second shaft in spaced apart relationship therewith and rotatably held in the other end shield, the third shaft protruding out of the other end shield, the second shaft being rotatably held in the third shaft and protruding out of the third shaft and a third rotor comprising a recessed portion formed at the inner end of the second shaft and rotatably held at the inner end of the first shaft, the third rotor further comprising a radial rim extending upto the other end face of the stator in spaced apart relationship therewith and having a fourth set of rotor magnets mounted at the inner surface thereof describing a gap with the other end face of the stator.

2. The electric motor as claimed in claim 1, wherein a pulley is mounted on the protruding end of the third shaft.
3. The electric motor as claimed in claim 1 or 2, which comprises a mounting bracket fixed thereto.
4. A multi drive electric motor comprising a housing formed of two end shields fitted together, a first shaft and a second shaft disposed in the housing in axially spaced apart relationship with each other, a first rotor mounted on the first shaft and having a first set of rotor magnets mounted on the outer circumference thereof describing a gap with the inner circumference of a stator disposed over the first rotor in spaced apart relationship therewith and fitted in the housing, a second rotor comprising a disc portion disposed in spaced apart relationship with one end face of the stator and having a second set of rotor magnets mounted thereon describing a gap with the said one end face of the stator, the second rotor having a third shaft rotatably mounted in the one end shield and extending over the second shaft in spaced apart relationship therewith and protruding out of the one end enshield, the first shaft protruding out of the third shaft and being rotatably mounted in the third shaft, a third rotor comprising a cup shaped portion disposed over the outer circumference of the stator in spaced apart relationship therewith and having a third set of rotor magnets mounted on the inner circumference thereof describing a gap with the outer circumference of the stator, the third rotor further comprising a fourth shaft extending over the second shaft in spaced apart relationship therewith and being rotatably held in the other end shield, the fourth shaft protruding out of the other end shield, the second shaft being rotatably held in the fourth shaft and protruding out of the fourth shaft and a fourth rotor comprising a recessed portion formed at the inner end of the second shaft and

rotatably held at the inner end of the first shaft, the fourth rotor further comprising a radial rim extending upto the other end face of the stator in spaced apart relationship therewith and having a fourth set of rotor magnets mounted at the inner surface thereof describing a gap with the other end face of the stator.
5. The electric motor as claimed in claim 3, wherein a pulley is mounted on the protruding end of each of the second shaft and fourth shaft.
6. The electric motor as claimed in claim 4 or 5, which comprises a mounting bracket fixed thereto.

Abstract
A multi drive electric motor (1A) comprising a housing (2) formed of two end shields (3 & 4) fitted together. A first shaft (6) and a second shaft (7) are disposed in the housing in axially spaced apart relationship with each other. The first shaft is rotatably held in one end shield (3) and protrudes out of the said one end shield. 9 is a first rotor mounted on the first shaft and having a first set of rotor magnets (10) mounted on the outer circumference thereof describing a gap (not marked) with the inner circumference of a stator (11) disposed over the first rotor in spaced apart relationship therewith and fitted in the housing. The first rotor further comprises an angular projection (13) projecting from one end face thereof. One limb (13a) of the angular projection is disposed in spaced apart relationship with one end face of the stator and has a second set of rotor magnets (14) mounted on the inner surface thereof describing a gap (not shown) with the said one end face of the stator. 15 is a second rotor comprising a cup shaped portion (16) disposed over the outer circumference of the stator in spaced apart relationship therewith and having a third set of rotor magnets (17) mounted on the inner circumference thereof describing a gap (not shown) with the outer circumference of the stator. The second rotor further comprises a third shaft (18) extending over the second shaft (7) in spaced apart relationship therewith and rotatably held in the other end shield (4). The third shaft protrudes out of the other end shield (4). The second shaft is rotatably held in the third shaft and protrudes out of the third shaft. (21) is a third rotor comprising a recessed portion (22) formed at the inner end of the second shaft and rotatably held at the inner end of the first shaft. The third rotor further comprises a radial rim (24) extending upto the other end face of the stator in spaced apart relationship therewith and having a fourth set of rotor magnets (25) mounted at the inner surface thereof describing a gap with the other end face of the stator (Fig 1).