Electric machine having a stator winding with rigid bars

1. An electric machine ( 1 ) having a central axis ( 3 ) of rotation and comprising:

a stator ( 5 ) comprising a magnetic core ( 6 ) longitudinally crossed by a plurality of stator slots ( 7 ); and

a stator winding ( 8 ) having a number of phases and comprising a series of rigid bars ( 9 ), wherein said rigid bars ( 9 ) are “U”-shaped and define legs, said rigid bars are inserted through the stator slots ( 7 ) defining an entry side ( 12 ), through which said entry side cusps ( 11 ) of the “U”-shaped bars ( 9 ) are placed, and said stator slots ( 7 ) defining an exit side ( 13 ), in which exit side ( 13 ) legs ( 10 ) of the “U”-shaped bars ( 9 ) are placed;

wherein the legs ( 10 ) of the “U”-shaped bars ( 9 ) extending out from the exit side ( 13 ) of the magnetic core ( 6 ) are twisted through relative double folds, each of said double folds comprises an internal fold ( 15 ) in one direction and an external fold ( 16 ) in an opposite direction;

wherein the ends of the legs ( 10 ) of the “U”-shaped bars ( 9 ) are electrically connected to one another so as to form the electrical paths of the stator winding ( 8 );

wherein the ends of at least two non-adjacent legs ( 10 ) are electrically connected to one another by a connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) made of a flat plate arranged perpendicular to the central axis ( 3 ) of rotation and has, for each leg ( 10 ), a corresponding “U”-shaped seat ( 19 ), wherein said “U”-shaped seat ( 19 ) acts to receive the end of the leg ( 10 );

wherein an insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) made of an electrically insulating plastic material, houses the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ), is arranged under the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) and has a plurality of through holes ( 22 ), into which through holes ( 22 ) some legs ( 10 ) are inserted, wherein said legs ( 10 ) have to pass through the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 );

wherein the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) comprises at least one seat ( 25 ), said seat ( 25 ) acting to receive and mechanically lock the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) in a predetermined position; and

wherein the seat ( 25 ) is made up of restraining elements ( 26 ) projecting upwards from a base ( 21 ) of the support ( 20 ; 29 ; 31 ; 33 ; 35 ) and that are arranged in correspondence to the edge of the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ).

2. The electric machine ( 1 ) according to claim 1 , wherein some legs ( 10 ) extend beyond the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) and are connected to the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) or are connected to further elements arranged above the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ).

3. The electric machine ( 1 ) according to claim 1 , wherein the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) comprises a base ( 21 ), which is shaped as a circular arc, is crossed by the through holes ( 22 ) and has a lower surface, which rests against the ends of the legs ( 10 ) arranged under it, and an upper surface, on which upper surface the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) rests.

4. The electric machine ( 1 ) according to claim 1 , wherein the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) comprises a plurality of positioning elements ( 23 ) projecting downwards from a lower surface of a base ( 21 ) of the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ), are arranged radially and are interlocked in gaps available between the ends of the legs ( 10 ) arranged under the positioning elements ( 23 ).

5. The electric machine ( 1 ) according to claim 1 , wherein the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) comprises a plurality of columns ( 24 ) projecting upwards from the upper surface of a base ( 21 ) of the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) and that provide a mechanical support for further elements arranged above the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ).

6. The electric machine ( 1 ) according to claim 5 , wherein the columns ( 24 ) are arranged circumferentially both on the internal edge and on the external edge of the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ).

7. The electric machine ( 1 ) according to claim 1 , wherein at least part of the restraining elements ( 26 ) elastically deform so as to allow the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) to enter the seat ( 25 ).

8. The electric machine ( 1 ) according to claim 7 , wherein at least part of the restraining elements ( 26 ) have a tooth ( 27 ) that rests on an upper surface of the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) following an elastic deformation of the restraining element ( 26 ).

9. An electric machine ( 1 ) having a central axis ( 3 ) of rotation and comprising:

a stator ( 5 ) comprising a magnetic core ( 6 ) longitudinally crossed by a plurality of stator slots ( 7 ); and

a stator winding ( 8 ) having a number of phases and comprising a series of rigid bars ( 9 ) that are “U”-shaped and define legs, said rigid bars are inserted through the stator slots ( 7 ) defining an entry side ( 12 ), through which entry side cusps ( 11 ) of the “U”-shaped bars ( 9 ) are placed, and an exit side ( 13 ), in which exit side ( 13 ) legs ( 10 ) of the “U”-shaped bars ( 9 ) are placed;

wherein the legs ( 10 ) of the “U”-shaped bars ( 9 ) extending out from the exit side ( 13 ) of the magnetic core ( 6 ) are twisted through relative double folds, each of said double folds comprises an internal fold ( 15 ) in one direction and an external fold ( 16 ) in an opposite direction;

wherein the ends of the legs ( 10 ) of the “U”-shaped bars ( 9 ) are electrically connected to one another so as to form the electrical paths of the stator winding ( 8 );

wherein the ends of at least two non-adjacent legs ( 10 ) are electrically connected to one another by a connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ), wherein said connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) is made of a flat plate arranged perpendicular to the central axis ( 3 ) of rotation and has, for each leg ( 10 ), a corresponding “U”-shaped seat ( 19 ), said “U”-shaped seat ( 19 ) acting to receive the end of the leg ( 10 );

wherein an insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) made of an electrically insulating plastic material, houses the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ), is arranged under the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) and has a plurality of through holes ( 22 ), into said through holes ( 22 ) some legs ( 10 ) are inserted, such that said legs ( 10 ) pass through the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 );

wherein the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) comprises a plurality of positioning elements ( 23 ) that project downwards from a lower surface of the a base ( 21 ) of the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ), are arranged radially and are interlocked in gaps available between the ends of the legs ( 10 ) arranged under the positioning elements ( 23 ).

10. An electric machine ( 1 ) having a central axis ( 3 ) of rotation and comprising:

a stator ( 5 ) comprising a magnetic core ( 6 ) longitudinally crossed by a plurality of stator slots ( 7 ); and

a stator winding ( 8 ) having a number of phases and comprising a series of rigid bars ( 9 ) said rigid bars ( 9 ) having a “U”-shape such that they define legs, said rigid bars are inserted through the stator slots ( 7 ) defining an entry side ( 12 ) having entry side cusps ( 11 ) in which said “U”-shaped bars ( 9 ) are placed, and an exit side ( 13 ), in which exit side ( 13 ) legs ( 10 ) of the “U”-shaped bars ( 9 ) are placed;

wherein the legs ( 10 ) of the “U”-shaped bars ( 9 ) extending out from the exit side ( 13 ) of the magnetic core ( 6 ) are twisted through relative double folds, each of said double folds comprises an internal fold ( 15 ) in one direction and an external fold ( 16 ) in an opposite direction;

wherein the ends of the legs ( 10 ) of the “U”-shaped bars ( 9 ) are electrically connected to one another so as to form the electrical paths of the stator winding ( 8 );

wherein the ends of at least two non-adjacent legs ( 10 ) are electrically connected to one another by a connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ), wherein said connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) is a flat plate arranged perpendicular to the central axis ( 3 ) of rotation and has, for each leg ( 10 ), a corresponding “U”-shaped seat ( 19 ), said “U”-shaped seats ( 19 ) acting to receive the end of the leg ( 10 );

wherein an insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) made of an electrically insulating plastic material, houses the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ), is arranged under the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) and has a plurality of through holes ( 22 ), wherein some legs ( 10 ) are inserted into said through holes ( 22 ) and said legs ( 10 ) pass through the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ); and

wherein the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) comprises a plurality of columns ( 24 ) that project upwards from the upper surface of a base ( 21 ) of the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) and provide a mechanical support for further elements arranged above the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ).

11. The electric machine ( 1 ) according to claim 10 , wherein the columns ( 24 ) are arranged circumferentially both on the internal edge and on the external edge of the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ).

12. An electric machine ( 1 ) having a central axis ( 3 ) of rotation and comprising:

a stator ( 5 ) comprising a magnetic core ( 6 ) longitudinally crossed by a plurality of stator slots ( 7 ); and

a stator winding ( 8 ) having a number of phases and comprising a series of rigid bars ( 9 ) having a “U”-shape such that they define legs, said rigid bars are inserted through the stator slots ( 7 ) defining an entry side ( 12 ), having entry side cusps ( 11 ) in which said “U”-shaped bars ( 9 ) are placed, and an exit side ( 13 ), in which exit side ( 13 ) legs ( 10 ) of the “U”-shaped bars ( 9 ) are placed;

wherein the legs ( 10 ) of the “U”-shaped bars ( 9 ) extending out from the exit side ( 13 ) of the magnetic core ( 6 ) are twisted through relative double folds, each of said double folds comprises an internal fold ( 15 ) in one direction and an external fold ( 16 ) in an opposite direction;

wherein the ends of the legs ( 10 ) of the “U”-shaped bars ( 9 ) are electrically connected to one another so as to form the electrical paths of the stator winding ( 8 );

wherein the ends of at least two non-adjacent legs ( 10 ) are electrically connected to one another by a connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) made of a flat plate arranged perpendicular to the central axis ( 3 ) of rotation and has, for each leg ( 10 ), a corresponding “U”-shaped seat ( 19 ), wherein said “U”-shaped seat ( 19 ) acts to receive the end of the leg ( 10 );

wherein an insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) made of an electrically insulating plastic material, houses the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ), is arranged under the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) and has a plurality of through holes ( 22 ), into which some legs ( 10 ) are inserted, said legs ( 10 ) passing through the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 );

wherein the insulating support ( 20 ; 29 ; 31 ; 33 ; 35 ) comprises at least one seat ( 25 ) acting to receive and mechanically lock the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) in a correct position; and

wherein the seat ( 25 ) includes restraining elements ( 26 ) that project upwards from a base ( 21 ) of the support ( 20 ; 29 ; 31 ; 33 ; 35 ) and are arranged in correspondence to the edge of the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ).

13. The electric machine ( 1 ) according to claim 12 , wherein at least part of the restraining elements ( 26 ) elastically deform so as to allow the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) to enter the seat ( 25 ).

14. The electric machine ( 1 ) according to claim 13 , wherein at least part of the restraining elements ( 26 ) have a tooth ( 27 ) that rests on an upper surface of the connection bridge ( 18 ; 28 ; 30 ; 32 ; 34 ) following an elastic deformation of the restraining element ( 26 ).