This need nevertheless contrasts with the, difficulties and the problems that can be encountered during the insertion of the bar conductors inside the slots, if these have been previously equipped with one or more respective insulating sheets.
Stator Winding Design Considerations (Electric Motors). This is a packing factor. conductors—that can be placed in a slot, assuming 100 percent fill.An algorithm for the filling factor calculation of electrical machines. Based on the geometry of the slot the maximum. copper filling factor and number.
In this case, in fact, there is the risk that the blocking of the bar conductors causes an undetermined bending of the same bar conductors, which in an automated method with simultaneous insertion of a plurality of bar conductors in the slots would lead to the blocking of the method and the production of bar conductor scraps with no possibility of recycling.Method for making a stator of an electric machine, the stator comprising a stator core, the stator core comprising a main body and a plurality of slots which are axially extended inside the main body and are adapted to receive bar conductors of a bar stator winding, the method comprising the steps of.The aforesaid stator windings with bar conductors are commonly called bar stator windings.Such portions thus flared act as stop elements provided for preventing the insulating sheets from being dragged along the slots during the insertion of the bar conductors inside the slots, in addition to acting as guide for the bar conductors during their insertion in the stator core.At the same time, the insertion step is such to obtain a high fill factor of the slots 8.
The object of the present description is to provide a method which allows meeting the above-indicated need.In FIG. 4, the simplified flow chart is shown of a method embodiment 20 for making a stator 1 as described above.Preferably, the aforesaid step 25 of hot shaping is simultaneously carried out for all the preshaped insulating sheets 10 inserted inside the slots 8 of the stator core 2.Finally, with reference to FIG. 7, it is observed that the apparatus 20 can be provided with a support and work surface 60 adapted to sustain the stator core 20 in abutment.
Only the stator of such electric machine was represented in the attached figures, since it is deemed that the remaining parts of an electric machine or generally of an electric or hybrid drive vehicle are widely known by a man skilled in the art.Once a desired operating temperature has been attained, the shaping bars 52, by means of the motor 57, 58, can be axially moved into a group for slidably penetrating inside the respective slots 8 of the stator core 2.With reference to the figures, a stator is indicated in its entirety with 1, such stator comprising a stator core 2.
The slot fill factor is the ratio between the cross-sectional area of all conductors in one slot and the entire slot area. Often, electrical machine designers aim for slot fill factors that are as large as possible in order to increase the power efficiency.It is clear that such stator can also be used in an electric machine employed as a generator or employed for alternatively performing the function of motor and the function of generator.In such stations, the stator core 2 can be borne by rotating the surface 60 in order, to be subjected to several separate working steps.During such insertion and subsequent removal, there is therefore a sliding of the hot shaping tool 53 on a free surface of the insulating sheet 10, with abutment against the inner walls of the slot 8, aimed to optimize the profile of the preshaped insulating sheet 10 shape inside the slot 8.The invention will be better understood from the following detailed description of its embodiments made as exemplifying and hence in no manner limiting in relation to the drawing set, in which.
With reference to FIGS. 5-7, an embodiment of an apparatus 50 for making a stator will be described, and in particular a shaping apparatus 50 for the shape stabilization of at least one preshaped insulating sheet, by means of which the hot shaping step 25 can be carried out of the preshaped insulating sheets after the insertion thereof in the stator core.Based on contingent needs, it is also possible to provide for inserting, in a same slot, two or more preshaped insulating sheets.A stator core extends along a longitudinal axis and includes a yoke, and a plurality of radially-inwardly projecting teeth separated by intervening slots.The hot shaping bars 53 are housed in a housing seat 55 which is operatively heated by a distributed heating element 59 provided for in the equipment 20.
Through the described process, it is possible to make stators with bar winding having a stator core with relatively high height and slot fill factor.In the figures, equivalent or similar elements are indicated with the same numeric references.In addition, it is also clear that the flaring, step 24 can be simultaneously carried out for all the insulating sheets 10 housed in the stator core 2, by executing such, step via a circular formation comprising a plurality of conical flaring elements 54.In particular, a stator of the aforesaid type was achieved in which the fill factor is greater than or equal to 85%.Therefore, when the bars 53 are housed in the housing seat 55, these are preheated due to the distributed heating element 59.
The tubular housing 52 in particular hosts a plurality of hot shaping bar pairs 53 circumferentially arranged around a work axis z 1 of the apparatus 50.The flaring step 24 can be executed before the hot shaping step 25 or, in accordance with a preferred embodiment, simultaneously or at least with partial time overlapping with the hot shaping step 25.Patent US8918986 - Method for making a high fill factor stator for an electrical machine Advanced Patent Search Try the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.