CN115298927A

CN115298927A - Laminated core for an electric machine, electric machine having a laminated core, and method for producing a stator base body

Info

Publication number: CN115298927A
Application number: CN202180026431.3A
Authority: CN
Inventors: D·阿伦斯; A·纽鲍尔; A·埃韦特; T·柯尼格
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-04-09
Filing date: 2021-04-07
Publication date: 2022-11-04
Also published as: WO2021204830A1; DE102020204576A1

Abstract

Laminated core (10) for forming a pole of an electric machine (12), electric machine (12) and method for producing a stator base body (16) with individual metal sheets (20) laminated onto one another in an axial direction, which metal sheets form a T-shaped section (22) having a radially outer yoke region (24) with an outer circumference (25) and radially inwardly projecting tooth webs (26), wherein the metal sheets (20) have, at the yoke region (24), a connecting projection (30) on a first side (18) in a tangential direction (9) and, at a second side (19), a corresponding recess (31) for the connecting projection (30) in a tangentially opposite manner, wherein, at least at a radially inner side (33) of the connecting projection (30), an inner circular arc section (35) is formed, the outer center (37) of which lies radially within the yoke region (26) at a radial distance (47) from the outer circumference (25).

Description

Laminated core for an electric machine, electric machine having a laminated core, and method for producing a stator base body

Technical Field

The invention relates to a laminated core for an electric machine, to an electric machine having a laminated core, and to a method for producing a stator base body according to the type of the independent claims.

Background

DE 102017201178A1 discloses a stator of an electric machine, in which a laminated core is formed from a single stamped metal sheet in an axial stack. In this case, a stamped encapsulation is formed in the radially outer yoke region, which connects the individual metal sheets to one another in the axial direction. In order to join the individual laminated core sections together, tab-like projections are formed tangentially at the laminated core sections, which engage in corresponding tangential recesses. A disadvantage in this embodiment is that this geometry of the tab-like projections is not suitable for producing a stator by means of a pre-cutting technique in which the individual laminated core segments are separated at the intended breaking point and then joined to one another again at exactly the same point. These disadvantages are to be eliminated by the solution according to the invention, wherein the magnetic flux losses in the yoke region of the laminated core are to be minimized.

Disclosure of Invention

The device according to the invention and the method according to the invention with the features of the independent claims have the advantage that T-shaped metal sections can be joined to form a total base body particularly advantageously over the entire circumference by the special geometry of the connecting projections of the T-shaped metal sections. The geometry of the connecting projections and the corresponding recesses for the connecting projections are optimized for a so-called "pre-cut production method", in which the individual sheet metal layers are stamped to some extent in full cut with predefined predetermined breaking points between the individual T-shaped sections. In this case, the individual T-segments are separated from the sheet metal base, so that their tooth shanks can be wound better. Therefore, higher duty factor of the wire chase can be achieved, and the higher duty factor of the wire chase improves the efficiency of the motor. If an inner circular-arc section is punched at the radially inner side of the connecting projection (toward the tooth shank), the center of which is located radially in the yoke region of the T-shaped section, two adjacent T-shaped sections are separated with minimal force loss without their connecting projection being deformed during separation. By maintaining the contour of the connecting projections when the T-shaped sections are separated, the T-shaped sections can be joined together again very accurately after they have been wound, so that there is virtually no joint gap between the individual T-shaped sections in the tangential direction. The detent torque and thus the noise generation of the electric machine can thereby be reduced very effectively. Furthermore, the electromagnetic resistance is minimized and the asymmetry is reduced, which leads to better efficiency.

Advantageous embodiments and refinements of the embodiments specified in the independent claims are achieved by the measures mentioned in the dependent claims. The connecting projection extends in the tangential direction from a tangential side of the T-shaped section, which extends substantially in the radial direction. The radially inner circular-arc contour of the connecting projection is designed such that the center of the radially inner circular contour has a distance from the tangent of the radially extending boundary line of the side of the T-shaped section. This prevents the engagement of the connecting projections with the associated recesses when the T-shaped sections are separated when the T-shaped sections are tilted. This ensures that even in the non-optimal tangential separation direction, no deformation of the connecting projections and/or recesses occurs during separation. Interference of the magnetic flux between two adjacent T-shaped sections joined together can thereby be minimized.

It has proven to be particularly advantageous if the centers of the inner flank profiles have a spacing of 0.05 to 1.0 mm, particularly preferably 0.1 to 0.3 mm. If the tooth shanks of the T-shaped sections of the inner rotor motor extend, for example, radially inward, adjacent T-shaped sections can also be separated without deformation if the tooth shanks are inclined relative to the radially extending dividing line. If the radially inner tooth roots of the tooth shanks are moved away from one another more strongly, for example with respect to the tangential direction, than the associated yoke regions, it can be ensured that the radially inner contour of the connecting projections, when apart, does not rub against the corresponding recesses. If the center of the radial inner contour of the connecting lug is arranged radially inside the connecting lug, the comparatively strong circular curvature of the inner side faces ensures that the inner side face contour forms a gap with the corresponding recess even when the T-shaped section is tilted about the outer contour of the yoke region. This reliably prevents the T-shaped section from being deformed at the junction gap when the T-shaped section is separated when the T-shaped section is undesirably tilted.

In the pre-cutting technique, it may also be the case that, during the separation of the T-shaped sections, these T-shaped sections are inclined at the inner circumference of the yoke region, so that the radially outer yoke regions are moved further away from one another than the radially inner yoke regions or tooth roots. In order to ensure that the T-shaped sections are separated without deformation also for this case, it may optionally also be advantageous to design the radial outer contour of the connecting projection as a circular arc segment, the center point of which is arranged radially outside the inner diameter of the yoke region. Preferably, the center of this inner circle of the projection contour for the outer part can likewise preferably be arranged in the radial extension of the connecting projection.

If the inner circle center of the outer circular arc segment for the connecting projection is also arranged at a tangential distance from the radial boundary line of the yoke region, the connecting projection can likewise be reliably prevented from being deformed during the separation of the T-shaped sections. In a preferred embodiment, the outer circular arc section is configured radially mirror-symmetrically to the inner circular arc section of the connecting projection. The radially inner center of the circle is preferably arranged radially flush with the radially outer center of the circle at a radial distance from one another. In a preferred embodiment, the connecting projection has a flat surface at its tangentially outermost end, which surface extends substantially in the radial direction.

The inner and/or outer circular arc segment preferably does not extend tangentially exactly to the boundary line of the yoke region. Rather, for manufacturing reasons and to avoid notch cracks, a transition region of a radius or other shape is formed between the circular arc segment and the boundary line, for example. The tangential extent thereof preferably corresponds to the tangential spacing of the inner and/or outer circle center from the radial boundary line. This means that the circular arc segment does not extend over the entire tangential extent (height) of the connecting projection, but rather is formed as a precise circular arc only in the tangential partial regions.

The connecting projection is preferably not arranged exactly radially centrally in the yoke region, but is offset from the center radially outward toward the outer circumference. In this case, the radial distance between the outer circumference of the yoke region and the radially outer flank of the connecting projection is in the order of magnitude of the tangential height and/or the radial width of the connecting projection. In this way, a straight region of the dividing line that is longer in the radial direction is retained in the radially inner region than in the radially outer region, which positively influences the undisturbed magnetic flux between adjacent T-shaped sections. However, depending on the overall diameter of the stator or of the laser welding process, the radial distance between the outer circumference of the yoke region and the radially outer side of the connection projection may also have a different size than the tangential height and/or the radial width of the connection projection.

In the stamping of the metal sheet, the individual T-shaped sections are particularly advantageously connected to the adjacent metal sheet in one operation by means of the stamped encapsulation in the axial direction. This eliminates an additional connecting process between the metal sheets stacked in the axial direction. The stamped-out encapsulation securely holds the laminations of the individual T-shaped sections to one another in the axial direction after the T-shaped sections have been separated, so that their tooth shanks can be wound in a simple manner by means of a coil wire, for example an enamelled copper wire. In this case, the T-shaped sections can also be wrapped, for example, with an uninterrupted coil wire. The stamped encapsulation is preferably configured as an elongated bead, the longitudinal direction of which is particularly advantageously oriented along the magnetic field lines in the T-shaped section.

The laminated core is particularly advantageously suitable for forming a stator consisting of a T-shaped single segment, the tooth shank of which extends radially inwards. After winding the tooth shank, each T-shaped stator segment provides a separate stator pole that cooperates with the rotor as an inner rotor.

The windings of the T-shaped section are preferably designed as single-tooth windings, which are energized in the control electronics of the electric machine. The single-tooth coils can be connected to the electronically commutatable electric motor in various ways.

By manufacturing the stator base body by means of a so-called "pre-cut" method, the advantages of freely accessible winding tooth shanks can be combined with the advantages of the stator yoke, leaving only a minimum joint gap between the individual T-shaped segments. In this case, all T-shaped metal sheets are separated from only one sheet metal layer almost simultaneously in a first step during the stamping process and are pressed back into the initial position again in the axial direction in a second step. This creates a predetermined breaking point in the yoke region at the separation point, wherein the individual T-segments remain connected to one another over the entire circumference also as a stator base body. During the stamping, the individual sheet metal layers are preferably connected to one another in the axial direction by means of the stamped encapsulation. The individual T-shaped sections are separated from the stator base shortly before the tooth shank is wound. After the winding of the tooth shank, the split T-segments again engage in the initial position as a ring, wherein the intended breaking points again engage in each other exactly tangentially.

By forming the inner and/or outer circular arc sections at the side faces of the connecting projection, a snap-in between the connecting projection and the adjacent groove can be prevented, provided that the T-shaped sections are tilted or rotated relative to each other upon separation.

In order to separate the T-shaped sections, the separating wedge is introduced axially into the groove of the stator base body in a particularly simple manner. This results in a tangential separating force between adjacent tooth segments, which separating force results in a separation of the tooth segments at the intended breaking point. If the separating force caused by the separating wedge deviates from the exact tangential direction, the tooth segments of the T-shape are slightly inclined relative to one another, so that the yoke regions do not move away from one another as strongly at their outer circumference and at their inner diameter. This can occur, for example, in that the separating wedge has a greater force or a greater force on the tooth shank in the region of the tooth shank than in the radially outer region of the tooth shank. However, due to the geometry of the connecting projection according to the invention, this suboptimal detachment force does not lead to a deformation of the connecting projection or of the corresponding receptacle.

The arrangement and design of the laminated core of the stator segments designed as T-shaped stator segments has proven to be particularly advantageous. Such a stator segment forms a single-tooth segment in which exactly one tooth shank extends in the radial direction at the yoke region in the form of an annular segment. An electrical coil is wound onto this shank, which electrical coil then forms a magnetic pole acting in the radial direction at the tooth shoe. The electrical coils are preferably designed as single-tooth coils which are wound onto an insulating sleeve which is placed over the stator segments. A plurality of such T-shaped stator segments can be assembled to form a stator which is closed in the form of a ring, wherein the yoke regions respectively bear against one another in the tangential direction. In the stator or rotor, as an alternative to the electrical winding, permanent magnets can also be arranged, wherein the laminated core then forms a magnetic ground for this purpose. A stator and/or rotor formed from a laminated core can be constructed very cost-effectively as part of an electrical machine, in particular an electric motor. The plurality of T-shaped single-tooth segments can be assembled, for example, as a stator, whose electrical windings are commutated brushless. For this purpose, control electronics are preferably arranged axially above the stator segments, by means of which the individual electrical coils are connected to one another. In such an embodiment, a rotor may be arranged in the tooth neck, in which, for example, permanent magnets are arranged.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the description that follows.

Drawings

Fig. 1 is a schematic cross-sectional view of an electric machine with a laminated core in the shape of a T; and is

Fig. 2 is an enlarged view of a section of the laminated core according to the invention according to fig. 1; and is

Fig. 3 schematically shows the separation of two laminated cores.

Detailed Description

Fig. 1 shows an electrically commutated motor 13 as an electric machine 12 according to the invention. The electric machine has radially on the outside a stator 14 with a stator base 16. The stator base 16 is assembled from a single T-section 22 having radially outward yoke regions 24 in which tooth shanks 26 extend radially inward therefrom. At the radially inner end of the tooth shank 26, a tooth root 28 is formed, which then forms a magnetic pole for the rotor 15, which is radially supported in the stator 14. An insulating cover 56 is arranged in each case on the T-shaped sections 22, which is then wound with an electrical winding 58. In this embodiment, each T-shaped section 22 has a single-tooth coil 59, which is connected to the control electronics of the electric motor 12 by way of a wiring device, not shown. In this case, one or more T-shaped segments 22 can also be wrapped, for example, with an uninterrupted winding wire. The stator base 16 is assembled from individual metal sheets 20, which are stacked axially up and down. The individual T-shaped sections 22 thus each form a laminated core 10. A plurality of laminated cores 10 (e.g., 12) form a stator base 16 over the entire circumference, which is inserted into a motor housing, not shown, for example. The individual metal sheets 20 are separated from one another by a lateral dividing line 40, which extends approximately in the radial direction 7 from the outer circumference 25 of the yoke region 24 to the inner diameter 23 thereof. At a first dividing line 40 of a T-shaped section 22, a connecting lug 30 extends in the tangential direction 9, which in the assembled state engages in a corresponding recess 31 of an adjacent T-shaped section 22. An enlarged portion of the yoke region 24 with the attachment lug 30 is shown in fig. 2, showing the specific geometry of the attachment lug. The rotor 15 has a plurality of permanent magnets 60 in fig. 1, which are accommodated in a rotor base 62. The permanent magnets 60 are arranged here, for example, on a radial surface of a rotor base body 62. In this case, retaining webs 64 at the rotor base 62 are formed between the permanent magnets 60 in the tangential direction 9, which separate the permanent magnets 60, which are preferably magnetized in the radial direction 7, from one another in the circumferential direction. In the embodiment, the permanent magnet 60 is configured in a shell shape, and thus the outer circumference 66 of the rotor 15 is configured substantially in a circular shape. In particular, eight permanent magnets 60 are arranged on the rotor 15, which interact with twelve stator poles formed by the T-shaped sections 22. In alternative embodiments, 15/12-or 12/10-or 12/14-motor topologies are used.

In fig. 2, yoke region 24 of laminated core 10 has an outer circumference 24 and an inner diameter 23. Either the outer circumference 25 or the inner diameter 23 may have an area other than a circular arc. For example, axial grooves 68 or sinusoidal or flat surfaces 70 can be integrated. However, decisive for the arrangement and for the shape of the connecting projections 30 are the inner diameter 23 and the outer circumference 25 in the region of the yoke region 24 toward the lateral boundary 40 of the adjacent laminated core 10. The lateral dividing line 40 extends over a substantial part of its extension in the radial direction 7. The connecting projections 30 extend in the tangential direction 9 from the lateral parting lines 40, where they engage in corresponding recesses 31 of the adjacent laminated core 10, as is shown in fig. 1. The connecting projection 30 has a radial inner side 33, which is designed as an inner circular arc segment 35. The outer center 37 of the inner circular arc segment 35 is located with a radial distance 47 in the outer circumference 25, in the particular configuration in particular within the radial extent, that is to say within the width 72 of the connecting projection 30. Furthermore, the outer circle center 37 is arranged at a tangential distance 44 from the lateral dividing line 40. The inner circle segment extends in the tangential direction 9 to the outer center 37 and then turns into the lateral boundary line 40 via the tangential transition region 74. The transition region 74 from the radially inner flank 33 to the lateral boundary line 40 can be formed, for example, with a radius in order to prevent gaps from forming in the transition region 74.

In this embodiment, in particular, the radially outer side 34 of the connection projection 30 is also formed as an outer circular section 36. The inner center 38 of the circular section is arranged outside the inner diameter 23 of the yoke region 24 at a radial distance 48. In this particular exemplary embodiment, the inner center 38 is likewise arranged within the radial width 72 of the connecting projection 30. The radial center 38 likewise has a spacing 44 from the lateral dividing line 40, which corresponds to the spacing 44 between the outer center 37 and the lateral dividing line 40. In the embodiment shown, the outer circular arc segment 36 is configured symmetrically to the inner circular arc segment 35. The plane of symmetry is formed here by a median line 75 running in the tangential direction 9 through the coupling projection 30. The outer circular arc segment 36 is also connected to the lateral dividing line 40 by a tangential transition region 74. The connecting projection 30 has at its tangential end a flat surface 42 which extends substantially in the radial direction 7 and thus parallel to the lateral dividing line 40. The connecting projections 30 are arranged at radial distances 50 between the outer circumference 25 and the radial outer side 34, outside the radial center of the yoke region 24. The distance 50 has, for example, the same size as the radial width 72 or the tangential height 71 of the connecting projection 30. The radial distance 51 between the inner diameter 23 and the radial inner side 33 is then in particular designed to be greater than the outer distance 50. The radial distance 52 between the inner center 38 and the outer center 37 may be, in particular, 30% to 90% of the radial width 72 of the connecting projection 30, but may also be greater than the radial width 72. The respective recess 31 of an adjacent laminated core 10 or of the same laminated core 10 at the laterally opposite boundary lines 40 in the tangential direction 9 has a geometry corresponding to this connecting projection 30. The lateral boundary line 40 with the connecting projection 30 and the opposite recess 31 is produced with a uniform punched edge. In this case, each individual metal sheet 20 in the yoke region 24 is not completely separated axially by this punching edge in a first step according to a pre-cutting method and is pressed back axially into the original position again in a second step in order to form the intended breaking point. This results in a stator base body 16 which is closed over the entire circumference and which is only separated during the winding of the individual T-segments 22.

This separation process is illustrated in fig. 3 by means of two laminated cores 10. The lateral boundary line 40 with the connecting projection 30 and the opposite recess 31 is also designed as a predetermined breaking point as a connecting structure for the two yoke regions 24. To separate two laminated cores 10, a separating wedge 92 is pressed axially into the stator slot 90 between the two tooth shanks 26. This separating wedge 92 generates a separating force between the two yoke regions 24, by means of which the intended breaking point is separated. The ideal separating force 94 is oriented exactly in the tangential direction 9 and thus perpendicular to the radial dividing line 40. The coupling projection 30 can be released from the recess 31 without deformation by this desired separating force 94. However, if a tilting moment 96 is generated by the separating wedge 92 about a tilting point 97 at the outer circumference 25, in principle, in this tilting, the connecting projection 30 and/or the recess 31 are deformed during tilting. In the illustrated exemplary position of the separating wedge 92 in the stator slot 90, it can be seen that the separating wedge 92 presses the tooth shanks 26 more strongly apart from one another in the region of the tooth root 28 than in the yoke region 24. In this case, a largely unavoidable, extensive tilting moment 96 is thus produced, which, due to our inventive geometry of the connection lug 30, does not result in destructive deformations. It is also theoretically possible that a compressive tilting moment 98 is generated during the detachment process around the inner tilting point 99 at the inner diameter 23. However, the geometry according to the invention of the

circular arc segments

35, 36 on the

flanks

33, 34 of the connecting lug 30 also prevents deformation of the connecting lug 30 and/or of the groove 31 in the event of such an

undesired tilting moment

96, 98. After separating the laminated cores 20, they are wound with electrical windings 58 and then pressed together again at their identical position in the tangential direction 9. The rated fracture points are thereby bonded together again, thereby minimizing a bonding gap between the respective laminated cores 10. Fig. 3 shows a stamped encapsulation 88, by means of which the individual laminated cores 20 are connected to one another in the axial direction. The stamped envelope 88 is arranged radially 7, for example with its longitudinal extension, in the shank 26. Two further stamped encapsulation structures 88 are each arranged in the yoke region 24, their longitudinal direction forming an angle with the tangential direction 9 and ideally being oriented along the occurring magnetic field lines.

It is to be noted that, with the embodiments shown in the figures and the description, various combination possibilities of the individual features with one another are possible. The specific contour of the individual laminated cores 20, the arrangement and number of tooth webs 26 and the design of the yoke regions 24 can thus be varied, for example, accordingly. It is likewise possible to form the inner circular arc segment 35 without forming the outer circular arc segment 36, or the contour of the inner side 33 can differ from the contour of the outer side 34. The radial position and size of the connecting projection 30 can also be adapted to the requirements of the electric machine 12 and its production possibilities. The invention is particularly suitable for the rotary drive of components or for adjusting parts in motor vehicles, but is not limited to this application.

Claims

1. Laminated core (10) for forming magnetic poles, in particular for a stator (14), of an electrical machine (12), having individual metal sheets (20) laminated to one another in an axial direction, which metal sheets form a T-shaped section (22) having a radially outer yoke region (24) with an outer circumference (25) and a radially inwardly projecting tooth flank (26), wherein the metal sheets (20) have a connecting projection (30) at a first side (18) in a tangential direction (9) and a corresponding recess (31) for the connecting projection (30) at a second side (19) in a tangentially opposite manner, wherein at least at a radially inner side (33) of the connecting projection (30) an inner circular arc segment (35) is formed, the outer center (37) of which lies radially within the yoke region (26) at a radial distance (47) from the outer circumference (25).

2. A laminated core (10) according to claim 1, wherein a lateral dividing line (40) is formed at the first side (18) at which the connecting projections (30) are arranged, said lateral dividing line extending along the radial direction (7) over a substantial part of its radial extent, and the outer circle centers (37) of the inner circle arc segments (35) are arranged in the tangential direction (9) at a distance (44) from the dividing line (40) in the direction of the connecting projections (30).

3. A laminated core (10) according to claim 1 or 2, wherein a distance (44) in a tangential direction (9) between said lateral radial dividing line (40) and said outer center (37) is 0.05 mm to 1.0 mm, in particular 0.05 mm to 0.3 mm.

4. A laminated core (10) according to any of the preceding claims, wherein a centre (37) of said outer portion is arranged in an area inside said joining projections (30) with respect to said radial direction (7).

5. A laminated core (10) according to any of the preceding claims, wherein an outer circular arc segment (36) is formed at a radially outer side face (34) of the coupling projection (30), and a center (38) of an inner portion of the circular arc segment is located radially outside an inner diameter (23) of the yoke region (24).

6. A laminated core (10) according to any one of the preceding claims, wherein the inner circle center (38) is arranged in the direction of the joining projection (30) at a distance from the dividing line (40) in the tangential direction (9), wherein the inner circle center (38) is preferably arranged radially in the region inside the joining projection (30), and wherein the outer circular arc segment (34) is constructed mirror-symmetrically with respect to the inner circular arc segment (35), in particular with respect to the radial direction (7).

7. A laminated core (10) according to any of the preceding claims, wherein tangential tips of said joining projections (30) are configured flattened and in particular have a flat face (42) in said radial direction (7).

8. A laminated core (10) according to any one of the preceding claims, wherein a transition region (74) is formed between the inner and/or outer circular arc segments (33, 34) and the lateral radial boundary line (40), wherein the extension of the transition region (74) corresponds substantially, in particular in the tangential direction (9), to the tangential distance (44) between the inner and/or outer circle center (38, 37) and the radial boundary line (40).

9. A laminated core (10) according to any one of the preceding claims, wherein said joining projections (30) are arranged outside a radial center of said lateral parting line (40) and a distance (50) between said radial outer side surface (34) and an outer circumference (25) of said yoke region (24) corresponds in particular approximately to a tangential height (71) or a radial width (72) of said joining projections (30).

10. A laminated core (10) according to any of the preceding claims, wherein said individual metal sheets (20) are connected to each other in axial direction by means of stamped encapsulation (88), wherein in particular a first stamped encapsulation (88) and one or two further stamped encapsulations (88) in said tooth shank (26) are symmetrically configured in said yoke region (26).

11. Stator (14) or rotor (15), characterized in that it is assembled from a plurality of laminated cores (10) according to any of the preceding claims and in that the tooth bars (26) are wound, in particular with electrical windings (58), to form the magnetic poles.

12. Electrical machine (12) having a stator (14) or a rotor (15) according to claim 11, wherein the electrical machine (12) is assembled from laminated cores (10) which are each designed as a T-segment (22), and the electrical windings (58) of the T-segments (22) are designed to be electronically commutable by means of control electronics.

13. Method for manufacturing a stator base body (16), in particular according to one of the preceding claims, characterized by the following method steps:

-stamping all the metal sheets (20) of only one sheet layer (21) by means of a pre-cutting technique, so that the T-shaped sections (22) of each sheet layer (21) remain connected to each other by means of a nominal breaking point,

-wherein in particular all T-shaped sections (22) of each sheet (21) are first stamped similarly to the full-cut technique in the stator arrangement and then almost completely separated from each other in a further stamping step and are pressed back again into the original position in a further step, whereby the individual T-shaped sections remain connected to each other only by small plastic deformations,

-stacking and connecting a plurality of sheet layers (21) in an axial direction to a stator base body (16), in particular by means of a stamped encapsulation (88),

-separating the stator base (16) into individual laminated cores (10) and winding the tooth webs (26) of the laminated cores,

-then joining the laminated core (10) to the stator base (16) just as before by connecting them to each other via predetermined breaking points.

14. Method according to claim 13, characterized in that only the radial dividing lines (40) with the connecting projections (30) and the corresponding recesses (31) are punched out by means of a pre-cutting technique,

and in that the connecting projection (30) is released from the groove (31) during the separation into the T-shaped sections (22), without the inner and/or outer circular arc sections (35, 36) being deformed.

15. Method according to claim 13 or 14, characterized in that the T-shaped section (22) is separated from the stator base body (16) by means of a separating wedge (92) which is pressed in the axial direction, in particular at two opposite axial end sides, between the tooth shanks (26).