Method and two-part tool arrangement for producing a stator for an electrical machine

1. A method for producing a stator, the method comprising the steps of:

providing a two-layer winding having a radially outer layer and a radially inner layer;

providing plurality of electrical conductor elements, a portion of the plurality of electrical conductor elements being part of the radially outer layer, and a portion of the plurality of electrical conductor elements being part of the radially inner layer;

providing a plurality of axial conductor ends, one or more of the plurality of axial conductor ends being part of a corresponding one of the plurality of electrical conductor elements;

providing a laminated core having an end face and a plurality of slots;

providing a normal skewing tool;

providing a selective skewing tool;

providing a normal region;

providing a connection region;

providing a plurality of pockets being part of the selective skewing tool, each of the plurality of pockets receiving a corresponding one of the plurality of axial conductor ends of one of the plurality of axial conductor elements located in the connecting region;

providing a plurality of sloping pocket walls, each one of the plurality of sloping pocket walls being part of one of the corresponding plurality of pockets;

arranging each of the plurality of electrical conductor elements in one or more of the slots such that a portion of the plurality of axial conductor ends are located in the normal region, and a portion of the plurality of axial conductor ends are located in the connecting region; and

providing a positioning process for one of the radially outer layer or the radially inner layer, the positioning process further comprising the steps of:

axially fitting the normal skewing tool with the plurality of axial conductor ends in the normal region;

turning the normal skewing tool with respect to the laminated core such that the plurality of axial conductor ends in the normal region are moved relative to one another;

axially fitting together the selective skewing tool with the plurality of axial conductor ends in the connecting region, such that the plurality of axial conductor ends the interconnecting region are in a relative end position in relation to one another and are intended for an interconnection of some of the conductor ends with corresponding conductor ends of the other of the radially outer layer or the radially inner layer;

moving the plurality of axial conductor ends with one or more of the pocket walls during the axially fitting together of the selective skewing tool with the plurality of axial conductor ends in the connecting region along a circumferential direction such that the plurality of axial conductor ends in the connecting region are moved in relation to one another.

2. The method of claim 1 , the positioning process further comprising the steps of:

moving the plurality of electrical conductor ends of the normal region in a first circumferential direction by a predetermined first turning angle; and

moving the plurality of electrical conductor ends of the interconnecting region in a second circumferential direction by a respective turning angle that is smaller than the first turning angle.

3. The method of claim 1 , further comprising the steps of:

arranging the plurality of electrical conductor elements in the slots such that each of the plurality of electrical conductor elements of both the radial outer layer and the radial inner layer protrude axially out of the end face as a straight conductor piece;

after the positioning process, jointly bending each straight conductor piece in a twisting process by relatively turning and axially bringing together the normal skewing tool and the selective skewing tool on and the laminated core, forming a skewing region of each straight conductor piece which has the same skewing angle with respect to the end face.

4. The method of claim 3 , the twisting process further comprising the steps of:

bending each conductor piece of the outer layer in one circumferential direction; and

bending each conductor piece of the inner layer in an opposite circumferential direction, each conductor piece of the outer layer and each conductive piece of the inner layer is arranged transposed in relation to one another.

5. The method of claim 3 , the twisting process further comprising the steps of: radially arranging the plurality of axial conductor ends of one of the radially outer layer ( 10 ) or the radially inner layer ( 11 ) moved by the normal skewing tool in line with the corresponding plurality of axial conductor ends of the other of the radially outer layer ( 10 ) or the radially inner layer.

6. The method of claim 3 , further comprising the steps of after the twisting process, only some of the conductor ends of one of the layers that are moved by the selective skewing tool are arranged radially in line with corresponding conductor ends of the other layer and, for each intended electrical coil of the stator, a conductor end of the conductor elements of the interconnecting region for each layer is respectively arranged between two adjacent conductor ends of the other layer.

7. The method of claim 3 , further comprising the steps of:

the positioning process further comprises arranging the plurality of axial conductor ends in a pocket of one of the normal skewing tool or the selective skewing tool; and

the twisting process further comprising the steps of cranking each of the plurality of electrical conductor elements between the skewing region and the plurality of axial conductor ends, so that each of the plurality of axial conductor ends remains aligned axially.

8. The method of claim 1 , further comprising the steps of:

providing each of the plurality of axial conductor elements to be straight bars or U-shaped wires for respectively arranging them in one of the plurality of slots;

inserting the plurality of axial conductor elements into a corresponding axial end of the plurality of slots;

pushing the plurality of axial conductor elements into the plurality of slots in the axial direction.

9. The method of claim 1 , further comprising:

a plurality of slots formed as part of the laminated core;

a plurality of radially inner slot openings, each of the plurality of radially inner slot openings integrally formed as part of a corresponding one of the plurality of slots;

wherein each of the plurality of radially inner slot openings have in the circumferential direction a slot width which is less than a dimension of each of the plurality of conductor elements that are respectively arranged in the plurality of slots.

10. A tool arrangement for producing a stator for an electrical machine, the tool arrangement comprising:

a normal skewing tool with respective pockets for receiving a conductor end of one or more of a plurality of conductor elements;

a selective skewing tool with respective pockets for receiving a conductor end of one of the plurality of the conductor elements;

a holding device for holding a laminated core in such a way that an end face of the laminated core is facing the normal skewing tool and the selective skewing tool; and

a movement device, the laminated core is arranged in the holding device and loaded with the plurality of conductor elements, each conductor end of a corresponding one of the plurality of conductor elements is arranged in one of the pockets of the normal skewing tool or one of the pockets of the selective skewing too in a positioning process;

one or more of the respective pockets of the selective skewing tool further comprising:

a sloping pocket wall arranged sloping with respect to the axial direction;

a sliding surface formed as part of the sloping pocket wall, the sliding surface pushes away the respective conductor end along a circumferential direction;

wherein during the positioning process the first the normal skewing tool is moved by the movement device along an axial direction up to the end face, and then turned in a circumferential direction with respect to the end face, and then the selective skewing tool is moved by the movement device along the axial direction up to the end face.

11. The tool arrangement of claim 10 , wherein, after the positioning process, the normal skewing tool and the selective skewing tool on and the laminated core are brought together in a twisting process and, during the twisting process the normal skewing tool and the selective skewing tool are turned jointly in relation to the laminated core, so that the plurality of conductor elements are uniformly bent by the same skewing angle with respect to the end face.