Method to improve adhesion of rotor magnets being embedded in an interior permanent magnet motor

1 . A method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor, the method comprising—

a) Applying a metered quantity of a viscous adhesive on an outer surface of the permanent magnet ( 01 ) which is foremost for insertion into the cavity ( 02 );

b) Applying a metered quantity of the viscous adhesive on an inner surface of the cavity ( 02 ) which is foremost for receiving the permanent magnet ( 01 ); and

c) Inserting the permanent magnet ( 01 ) into the rotor cavity ( 02 ), to cause counter-shear and hence opposing displacement of the viscous adhesive applied respectively on the permanent magnet ( 01 ) and the cavity ( 02 ) to result in improved embedding of the permanent magnet ( 01 ) within the cavity ( 02 ), said improvement being characterised in that—

the viscous adhesive is applied on mating surfaces of the permanent magnet ( 01 ) and the cavity ( 02 ) in either a bead or a ring configuration, any part of the same, or any combinations thereof in at least one pair of instances ( 04 A and 04 B) along an outer perimeter of the permanent magnet ( 01 ) near an end of the permanent magnet ( 01 ) that is first inserted into the cavity ( 02 ) and in at least another pair of instances ( 06 A and 06 B) on a mating inner perimeter surface of the cavity ( 02 ) near an opening of the cavity ( 02 ) that first receives the permanent magnet ( 01 ) when the permanent magnet ( 01 ) is inserted into the cavity ( 02 );

the viscous adhesive applied respectively on the permanent magnet ( 01 ) and the cavity ( 02 ) is uniformly spread and completely fills up a void space therebetween without any overflow through the counter-shear and opposing displacement of the viscous adhesive when the permanent magnet ( 01 ) is inserted into the rotor cavity ( 02 ); and

strength of adhesive-based bonding achieved corresponds to a debonding force of 139.5 kg.

2 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 1 , wherein the application of the viscous adhesive is undertaken via four specific instances in a bead configuration.

3 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 1 , wherein the metered quantities of adhesive for application on to the permanent magnet ( 01 ) and the cavity ( 02 ) are applied in predetermined amounts sufficient to completely fill the void space between lateral surfaces of the permanent magnet ( 01 ) and the inner surface of the receiving cavity ( 02 ) without any overflow when the permanent magnet ( 01 ) assumes a completely embedded position within its receiving cavity ( 02 ) in the rotor ( 03 ) of the interior permanent magnet motor.

4 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 3 , wherein the metered quantities of adhesive at the instances ( 04 A and 04 B) along the outer perimeter of the permanent magnet ( 01 ) are applied correspondingly on any pair of opposing or adjacent faces of said permanent magnet ( 01 ).

5 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 3 , wherein the metered quantities of adhesive at the instances ( 06 A and 06 B) on the inner perimeter of the cavity ( 02 ) are applied correspondingly on any pair of opposing or adjacent surfaces along the walls of said cavity ( 02 ).

6 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed claim 1 , wherein the viscous adhesive has a viscosity of 1000 P.

7 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 1 , wherein insertion of the viscous adhesive-bearing permanent magnet ( 01 ) into the adhesive-bearing rotor cavity ( 02 ) is undertaken manually.

8 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 1 , wherein insertion of the adhesive-bearing permanent magnet ( 01 ) into the adhesive-bearing rotor cavity ( 02 ) is undertaken in an automated manner using a pick and place device.

9 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 3 , wherein the metered quantity of adhesive applied on the outer surface of the permanent magnet ( 01 ) is applied correspondingly on any pair of opposing or adjacent faces of said permanent magnet ( 01 ).

10 . The method to improve adhesion of a permanent magnet ( 01 ) while being embedded within a cavity ( 02 ) in a rotor ( 03 ) of an interior permanent magnet motor as claimed in claim 3 , wherein the metered quantity of adhesive applied on to the inner surface of the cavity ( 02 ) is applied correspondingly on any pair of opposing or adjacent surfaces along the walls of said cavity ( 02 ).