Stator and method of manufacturing stator

Abstract

In a stator, segment coils each consisting of a pair of straight portions connected with a connecting portion in a U-like shape are set in slots of a stator core. Each straight portion has distal end parts protruding on an opposite side to the connecting portions. The distal end parts in odd-numbered positions from an outer or inner circumferential side in a radial direction are twisted in one direction and shaped radially outward and the distal end parts located in even-numbered positions are twisted in an opposite direction to the one direction and shaped radially inward to be joined to each other on the same circumference by welding.

1 . A stator in which a plurality of segment coils each consisting of a pair of straight portions connected with a connecting portion in a U-like shape are set in slots of a stator core, each of the pairs of straight portions having distal end parts protruding on an opposite side to the connecting portions, the distal end parts located in odd-numbered positions from an outer or inner circumferential side in a radial direction are twisted in one direction and the distal end parts located in even-numbered positions are twisted in an opposite direction to the one direction, and the distal end parts twisted in the one direction and the distal end parts twisted in the opposite direction are joined to each other by welding,
 wherein the distal end parts twisted in the one direction are shaped toward an outer circumference in the radial direction and the distal end parts twisted in the opposite direction are shaped toward an inner circumference in the radial direction, so that at least part of the distal end parts twisted in the one direction and the distal end parts twisted in the opposite direction are welded to each other on the same circumference, and 
 the distal end part of a first one of the coils, located on an outermost circumference, and the distal end part of a second one of the coils, located second from the outermost circumference, are located between a first position corresponding to an in-slot position of the first coil and a second position corresponding to an in-slot position of the second coil in the radial direction, and the distal end part of a third one of the coils, located third from the outermost circumference, and the distal end part of a fourth one of the coils, located fourth from the outermost circumference, are located between a third position corresponding to an in-slot position of the third coil and a fourth position corresponding to an in-slot position of the fourth coil in the radial direction. 
 
     
     
         2 . The stator according to  claim 1 , wherein
 the distal end parts twisted in the one direction are shaped toward the outer circumference in the radial direction by a length corresponding to half a thickness of the straight portion in the radial direction,   the distal end parts twisted in the opposite direction are shaped toward the inner circumference in the radial direction by a length corresponding to half the thickness of the straight portion in the radial direction, and   the distal end part of the first coil located on the outermost circumference and the distal end part of the second coil located second from the outermost circumference are located at a halfway position in the radial direction between the first position corresponding to the in-slot position of the first coil and the second position corresponding to the in-slot position of the second coil, and the distal end part of the third coil located third from the outermost circumference and the distal end part of the fourth coil located fourth from the outermost circumference are located at a halfway position in the radial direction between the third position corresponding to the in-slot position of the third coil and the fourth position corresponding to the in-slot position of the fourth coil.   
     
     
         3 . The stator according to  claim 1 , wherein the distal end part twisted in the one direction and the distal end part twisted in the opposite direction are located so that their end faces facing at the same position in a circumferential direction are placed in contact with each other. 
     
     
         4 . A method for manufacturing a stator, the method including:
 an inserting step of inserting segment coils, each constituting of a pair of straight portions connected with a connecting portion in a U-like shape, in slots of a stator core;   a twisting step of rotating a twisting ring while distal end parts of the pairs of straight portions protruding on an opposite side to the connecting portions are engaged with ring grooves of the twisting ring to twist and shape in one direction the distal end parts located in odd-numbered positions from an outer circumferential side or an inner circumferential side in a radial direction and twist and shape the distal end parts located in even-numbered positions in an opposite direction to the one direction; and   a welding step of welding the distal end parts twisted in the one direction and the distal end parts twisted in the opposite direction,   wherein the twisting step includes twisting and shaping the distal end parts twisted in the one direction and the distal end parts twisted in the opposite direction so that the distal end parts are placed in adjacent positions in a circumferential direction,   the method further includes a radial-direction shaping step, after the twisting step, of shaping the distal end parts twisted in the one direction toward an outer circumference in the radial direction and shaping the distal end parts twisted in the opposite direction toward an inner circumference in the radial direction, and   the radial-direction shaping step includes plastically deforming the distal end part of a first one of the coils, located on an outermost circumference, and the distal end part of a third one of the coils, located third from the outermost circumference, toward the inner circumference in the radial direction by use of an inner circumferential direction jig, and plastically deforming the distal end part of a second one of the coils, located second from the outermost circumference, and the distal end part of a fourth one of the coils, located fourth from the outermost circumference, toward the outer circumference in the radial direction by use of an outer circumferential direction jig.   
     
     
         5 . The method for manufacturing a stator according to  claim 4 ,
 wherein the radial-direction shaping step includes:
 shaping the distal end parts twisted in the one direction toward the outer circumference in the radial direction by a length corresponding to half a thickness of the straight portion in the radial direction; and 
 shaping the distal end parts twisted in the opposite direction toward the inner circumference in the radial direction by a length corresponding to half a thickness of the straight portion in the radial direction, and 
   wherein after the radial-direction shaping step, the distal end part of the first coil located on an outermost circumference and the distal end part of the second coil located second from the outermost circumference are located, in the radial direction, at a halfway position between a first position corresponding to an in-slot position of the first coil and a second position corresponding to an in-slot position of the second coil, and   after the radial-direction shaping step, the distal end part of the third coil located third from the outermost circumference and the distal end part of the fourth coil located fourth from the outermost circumference are located, in the radial direction, at a halfway position between a third position corresponding to an in-slot position of the third coil and a fourth position corresponding to an in-slot position of the fourth coil.   
     
     
         6 . The method for manufacturing a stator according to  claim 4 , wherein the distal end part twisted in the one direction and the distal end part twisted in the opposite direction are located so that their end faces facing at the same position in a circumferential direction are placed in contact with each other. 
     
     
         7 . The stator according to  claim 2 , wherein the distal end part twisted in the one direction and the distal end part twisted in the opposite direction are located so that their end faces facing at the same position in a circumferential direction are placed in contact with each other. 
     
     
         8 . The method for manufacturing a stator according to  claim 5 , wherein the distal end part twisted in the one direction and the distal end part twisted in the opposite direction are located so that their end faces facing at the same position in a circumferential direction are placed in contact with each other.