Lamellar body and electrical machine containing such, as well as a method for producing such

Abstract

The invention relates to a laminar body (12) of an electrical machine (10), in particular an EC motor, and to an electrical machine (10), having a plurality of individual laminations (14) which are arranged axially stacked one above the other and are connected to one another along an axial longitudinal axis (8) of the lamination body (12) by means of punched packages (21, 22, 23), wherein a plurality of punched packages (21, 22, 23) are formed on at least one individual lamination sheet (14), wherein at least one first punched package (21) has a first bulge (41) in a first axial direction (31) and at least one second punched package (22) has a second bulge (42) in a second axial direction (32) opposite to the first axial direction (31).

Description

State of the art

[0001] The invention is based on a lamella body and an electrical machine containing such a body, as well as a method for producing such a body according to the preamble of the independent claims.

[0002] DE 10 2008 000 291 A1 discloses an electric motor in which a laminated core is mounted on an armature shaft. The individual laminated cores are connected axially to form a laminated core by positive locking. The entire laminated core is pressed onto the armature shaft, and then the two end laminations are firmly connected to the armature shaft by means of ring caulking. As a result, the power transmission of the laminated core is higher at the two end faces than in the central axial area of ​​the laminated core. This is intended to prevent thermal stresses within the laminated core, but the strong, rigid connection of the end laminations further exacerbates radial runout of the armature shaft.

[0003] In such electric motors, external vibration and extreme temperature fluctuations can cause the axially outermost laminations to detach. This poses the risk of the armature winding wires breaking under severe external vibration, or of disturbing noises being generated by the vibration of the laminations. Disclosure of the inventionAdvantages of the invention

[0004] The laminar body according to the invention and the electrical machine comprising such a body, as well as the method for producing such a body, with the features of the independent claims, have the advantage that, by forming two different types of stamped stacks - or so-called interlocks - with bulges in axially opposite directions, both the upper end lamina and the lower end lamina can be reliably pressed against the rotor core. In contrast to conventional stamped stacks, sufficiently high axial holding forces can be applied by the two axially opposite last middle sheet metal laminations for the adjoining end laminations. As a result, a laminar body produced in this way can be easily pressed onto a rotor shaft or into a motor housing without damage and without the axially outer end laminations becoming loose.

[0005] The measures listed in the dependent claims enable advantageous further developments and improvements of the features specified in the independent claims. Because the axial bulges extend alternately in the first or second axial direction, a positive connection can be established over the entire surface of the edge-side middle laminations with the axially adjacent end laminations, which reliably fixes the end laminations to the lamination pack over their entire circumference and over their entire radial extent. For example, exactly two stamped laminations are arranged on a radial line of the middle laminations, while the number of stamped laminations preferably corresponds, for example, to the number of rotor poles over their entire circumference.

[0006] The plate pack is advantageously constructed in such a way that a plurality of identical middle plates are arranged axially one above the other, and the upper and lower end plates of the plate pack differ from the middle plates in the type of punched stacking formed. It is particularly advantageous to arrange third punched stackings on the upper and lower end plates, in which punchings are punched out as through holes. The corresponding axial bulges of the middle plates adjoining the end plates can then axially engage in these punchings of the two end plates. By axially pressing the plate sheets together, a positive connection can be achieved between the axial bulges and the punchings, which holds the end plates to the plate pack with a sufficiently large axial holding force.

[0007] On the lower end lamella, first punched packages are formed with an axial upward bulge, and on the other hand, third punched packages are punched out with the axial through holes. This allows the second bulges of the lowest middle lamella to engage axially downwards into the through holes of the lower end lamella. The axially upward bulges of the lower end lamella, on the other hand, engage axially upwards into the cavities of the corresponding first punched packages of the lowest middle lamella, which are aligned above them. Likewise, on the upper end lamella, second punched packages are formed with an axial downward bulge, and on the other hand, third punched packages are punched out with the axial through holes. This allows the first bulges of the uppermost middle lamella to engage axially upwards into the through holes of the upper end lamella.The axial downward bulges of the upper end lamella, on the other hand, engage axially downward into the cavities of the corresponding second punched packages of the uppermost middle lamella, which are located flush below.

[0008] Since the first and second punched stacks of the axial upward and downward bulges alternate around the circumference of all middle lamellas, the upper end lamella is rotated relative to the lower end lamella by the circumferential angle between two adjacent punched stacks. This ensures that the upward-facing first bulges of the uppermost middle lamella fit into the through-openings of the upper end lamella, and correspondingly, the downward-facing second bulges of the lowest middle lamella fit into the through-openings of the lower end lamella.

[0009] To ensure optimal magnetic flux in the lamination body, the punched stacks are particularly advantageously aligned with their longitudinal direction along the radial direction. Since the magnetic field lines in the stator base body and also in the rotor base body preferably run radially at their poles, recesses or deformations aligned in this way disrupt the magnetic field lines the least. However, it is also conceivable to design the punched stacks at a certain angle deviating from the radial direction in order to adapt their longitudinal direction to the course of the magnetic field lines, or to optimally utilize the geometry of the laminations. The axial bulges of the punched stacks are particularly advantageously formed as beads using an embossing die.

[0010] It is particularly advantageous if both the middle laminations and the end laminations extend as closed rings around the entire circumference. This allows for the formation of a mechanically stable lamination body that can be axially fitted with the permanent magnets or the electrical winding. Alternatively, however, the laminations can also be designed as ring segments that are assembled into a cylindrical, complete lamination body only after axial pressing.

[0011] Preferably, the laminations are assembled to form a rotor base body, which has a central recess for receiving a rotor shaft. The rotor base body is then equipped, in particular, with permanent magnets, which are arranged, for example, in spoke-like fashion in corresponding recesses of the rotor base body. Press-on tongues and centering lugs are preferably punched out of the central recess to create a precise press fit with the rotor shaft.

[0012] The laminations can also be advantageously assembled to form a stator base body, which has stator teeth with stator slots between them. The stator base body is then equipped, in particular, with an electrical winding, in which, for example, rigid wires are inserted axially into the stator slots as plug-in windings. The stator base body can then be inserted into a stator housing at its outer periphery, in particular to form a press fit.

[0013] The axial bulges of the first and second punched packages can be plastically formed into beads particularly favorably when punching out the sheet metal laminations by means of stamping dies.

[0014] The laminations can be punched particularly advantageously from an electrical steel sheet that has particularly good magnetic conductivity. By axially stacking many laminations with a relatively small axial sheet thickness of, for example, 0.2 - 1.0 mm, the formation of eddy currents in the lamination body can be largely prevented. If the axial bulges of the first and second punched stacks also have approximately the same axial dimension as the sheet thickness, a reliable form-fitting connection between the middle laminations can be achieved during the axial pressing of the laminations. When connecting the end laminations to the middle laminations, the first and second punched stacks can then engage axially into the punched through holes in the end laminations to such an extent that they do not protrude beyond the respective axially free end faces of the end laminations.

[0015] The rotor base body or stator base body according to the invention is installed in an electrical machine, preferably designed as an EC motor. Such a robustly designed electric motor can be installed, for example, in an e-bike or a motor vehicle, preferably in its engine compartment. Due to the vibration resistance and high thermal load capacity of the laminar body, such an electric motor can also be exposed to extreme environmental conditions. Such an electric motor can also be advantageously used to adjust moving parts or to drive pumps and fans in motor vehicles.

[0016] From a manufacturing perspective, the lamella body can be manufactured particularly advantageously using stamped sheet metal lamellas that are axially connected to one another by means of the first and second stamped stackings. Two different types of stamped stackings with bulges in opposite axial directions can be formed on the axially middle lamellas. These hold all the middle lamellas axially together, and the corresponding axial bulges of the uppermost middle lamella can be pressed into the axial openings of the upper end lamella, while the oppositely directed axial bulges of the lowest middle lamella can be pressed into the axial openings of the lower end lamella. Short description of the drawings

[0017] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

[0018] It shows Fig. 1 shows a first embodiment of a lamella sheet according to the invention, Fig. 2 schematically shows the assembly of a lamella body with a lamella sheet according to Fig. 1, Fig. 3 a lower end lamella according to the embodiment of Fig. 2, Fig. 4 shows a further embodiment of an assembly of a lamella body, Fig. 5 schematically shows the section through a lamella body according to Fig. 2 or Fig. 4, and Fig. 6 an embossing process of the punching packages.

[0019] In Fig. 1, a lamella plate 14 is shown as a middle lamella plate 18, as it is used to construct a lamella body 12 according to Fig. 2 is used. The lamination sheet 14 is punched out of an electrical sheet 13, for example to form a rotor base body 50 of an electrical machine 10. The lamination sheet 14 in Fig. 1 is formed as a closed ring in one piece over the entire circumference in the circumferential direction 9. Pressing tongues 55 and centering lugs 56 are punched out on a radial inner ring 57, by means of which the lamination plate 14 can be pressed onto a rotor shaft 52, as is the case, for example, in Fig. 3. Radial webs 58 extend outwards from the inner ring 57 in the radial direction 7, to which pole regions 59 are connected on the outside, which, in the assembled state of the electrical machine 10, form magnetic poles that interact with a stator of the electrical machine 10. In the circumferential direction 9, between the individual pole regions 59, recesses 54 for permanent magnets are formed, which are magnetized, for example, in the tangential direction 9. In each of the pole regions 59, a stamped stack 20 is formed, by means of which the individual laminations 14 are pressed together in the direction of a longitudinal axis 8 of the lamination body 12. In Fig. 1, different punched stacks 20 are formed for the middle laminations 18 in the circumferential direction 9, always alternating. On the right-hand side, a first punched stack 21 is shown, in which a first bulge 41 is formed upwards in a first axial direction 31. In the adjacent pole region 59, a second punched stack 22 is shown, in which a second bulge 42 is formed downwards in a second axial direction 32. Thus, a first punched stack 21 alternates with a second punched stack 22 in the circumferential direction 9 over the entire circumference. The first and second punched stacks 21, 22 are produced by means of stamping dies 81, 82 during the punching of the laminations 14, as is the case, for example, in Fig. 6. The punched packages 20 are designed as elongated beads 25, the dimension 27 of which in the radial direction 7 is larger than their dimension 29 in the circumferential direction 9. The beads 25 can have an approximately rectangular or rather oval shape.

[0020] In Fig. 2, several such middle slats 18 are now formed according to Fig. 1 are connected to one another along the longitudinal axis 8 by means of the punched packages 20. The first punched packages 21 of the individual middle lamellae 18 are arranged axially aligned one above the other, and the second punched packages 22 of the individual middle lamellae 18, which are located between them in the circumferential direction 9, are also arranged axially aligned one above the other. During axial compression, the bulges 41, 42 are then pressed into the corresponding cavities 44 of the adjacent lamellae 18. At the axial ends of the lamella body 12, an upper end lamella 15 is arranged at the top and a lower end lamella 16 at the bottom, which in Fig. 3. At the upper end plate 15, third punched packages 23 alternate with the second punched packages 22 in the circumferential direction 9. The second bulges 42 of the second punched package 22 engage in the cavities 44 of the underlying second punched package 22. In the upper end plate 15, the third punched packages 23 are arranged in the circumferential direction 9 between the second punched packages 22, into which the underlying first punched packages 21 axially engage. The edge of the punching holes 24 is plastically deformed, whereby the upper end plate 15 is reliably connected in a form-fitting manner to the underlying middle plate 18. In the embodiment of the Fig. 2, the upper end lamella 15 is designed to be closed at its radially outer periphery 94 so that the permanent magnets are reliably held in the radially outwardly closed recesses 54. In principle, further individual middle lamellae 18 can also have a radially outwardly closed periphery 94 between the pole regions 59 in order to hold the permanent magnets radially in the recesses 54.

[0021] The lower end lamella 16 in Fig. 3 has, in the circumferential direction 9, alternating first punched stacks 21 and through-punches 24 of third punched stacks 23. Corresponding to the upper end lamella 15, the second bulges 42 of the second punched stacks 22 of the middle lamella 18 located above engage axially with the through-punches 24 of end lamella 16 to form a firm positive connection. The first bulges 41 of the first punched stacks 21 arranged between them on the lower end lamella 16 in the circumferential direction 9 engage with the overlying cavities 44 of the corresponding first punched stacks 21. The lower end lamella 16, corresponding to the upper end lamella 15, again has a closed circumference 94 radially on the outside in order to form recesses 54 closed radially to the outside for the permanent magnets.On some laminations 14, a spring bar 53 is punched out radially inside the recesses 54, which elastically clamps the permanent magnets in the recesses 54. The assembled lamination body 12 of the . Fig. 2 forms a rotor base body 50, into which the permanent magnets are inserted in the axial direction 31, 32 into the recesses 54. A rotor produced in this way can be mounted radially within a stator, which preferably carries an electrical winding that is electronically commutated to rotate the rotor.

[0022] A stator base body 60 of such a stator is shown by way of example in Fig. 4 as a laminar body 12. The middle laminations 14 of the laminar body 12 here have stator teeth 66 that extend radially inward from a closed outer yoke ring 68. Stator slots 64 for receiving the electrical winding are formed between the stator teeth 66, wherein the stator slots 64 are particularly open radially inward. The upper end lamination 15 (and the lower end lamination 16, not shown) has a closed ring 70 on the radial inner side, which mechanically stabilizes the geometry of the stator slots 64. The laminations 14 are again particularly formed in one piece over the entire circumference. The stamped stacks 20 for axially connecting the middle laminations and the end laminations 15, 16, 18 are arranged in the radially outer yoke ring 68 and at the radially inner ends 67 of the stator teeth 66.On the left side, for example, the first punched stack 21 is formed at the inner end 67 of a stator tooth 66 on the middle laminations 18, the first bulge 41 of which extends upward in the first axial direction 31. Axially directly above this, a punched through 24 of the third punched stack 23 is formed in the upper end lamination 15. Thus, upon axial compression, the first bulge 41 engages axially in the punched through 24 of the upper end lamination 15 to form a reliable positive connection that firmly connects the upper end lamination 15 to the underlying middle lamination 18.Starting from the first punched stack 21 at the radially inner end 67 of the stator tooth 66, a second punched stack 22 is arranged on the uppermost middle lamination 18 at an outward distance in the radial direction 7 on the yoke ring 68, said second punched stack 22 forming a cavity 44 into which the second bulge 42 of the overlying second punched stack 22 of the upper end lamination 15 axially engages. Distributed over the circumference on the middle laminations 18, first and second punched stacks 21, 22 are alternately formed in the circumferential direction 9 at the yoke region 68 and at the radially inner ends 67 of certain stator teeth 66. On the upper end lamination 15, second and third punched stacks 22, 23 are alternately formed in the circumferential direction 9 at the yoke region 68 and at the radially inner stator tooth ends 67, respectively.On the lower end plate 16 (not shown), first and third stamped stacks 21, 23 are formed alternately, distributed along the circumference in the circumferential direction 9, on the yoke region 68 and on the radially inner stator tooth ends 67—or on the radially inner ring 70. As a result, the two end plates 15, 16 remain permanently fixed to the plate body 12.

[0023] Fig. Figure 5 shows a section in the radial direction 7 through a lamella body 12 according to the invention, in which the lamella sheets 14 are axially pressed together. The second bulges 42 of the second punched packages 22 engage in the corresponding cavities 44 along the second axial direction 32. The lower end lamella 16 here has the punched-through hole 24, into which the second bulge 42 axially engages. In the process, the edge 26 of the punched-through hole 24 is plastically deformed. The force flow during axial pressing is symbolized by the arrows 88. It can be seen that the second bulge 42 is deformed within the punched-through hole 24 transversely to the axial direction 32 against the edge 26 of the punched-through hole 24. Fig. 5, the axial thickness 34 of the lamella sheets 14 is approximately the same size as the axial dimension 35 of the second bulges 42. The axial dimension 35 of the second bulge 42 increases continuously, in particular over its longitudinal dimension 27 from the edge 26, and has the greatest maximum thickness 35 in the middle. The second bulge 42 of the lowest middle lamella 18, which engages axially into the punched-out portion 24, does not protrude beyond an axial end face 17 of the lower end lamella 16. On the right side, in Fig. 5 schematically shows a stator housing 62 into which the axially pressed lamella body 12 is axially inserted - in particular pressed - as the stator base body 60.

[0024] In Fig.6 schematically shows the production of the laminations 14. The laminations 14 are generally punched out of the solid electrical steel sheet 13 in several steps in order to achieve the final geometry step by step. During the punching process, the punched packages 21, 22 are also embossed into the lamination 14. For the first bulge 41, a first embossing die 81 on the right side presses the material of the electrical steel sheet 13 upwards in the first axial direction 31. To form the second bulge 42, a second embossing die 82 on the left side presses the material of the electrical steel sheet 13 downwards in the second axial direction 32. The first bulges 41 and the second bulges 42 are formed one after the other, in particular in two separate process steps.In an alternative process control, however, the first bulges 41 and the second bulges 42 can also be carried out in a common process step, in which the two stamping dies 81 and 82 are applied to the two axial end faces of the lamination sheets 14 in one step.

[0025] It should be noted that, with regard to the exemplary embodiments shown in the figures and in the description, a wide variety of combinations of the individual features are possible. For example, the axial dimension 35, as well as the radial and tangential dimensions 27, 29 and the shape of the stamped stacks 21, 22, 23 can be adapted to the various requirements of the electrical machine 10. The number and arrangement of the stamped stacks 21, 22, 23 on the laminations 14 can also be varied according to the manufacturing possibilities and the load of the electrical machine 10. The lamination body 12 can be designed as a rotor or stator base body 50, 60 that is formed integrally over the circumference or as several ring segments. After being joined to a rotor shaft 52 and the rotor base body 50 being equipped with permanent magnets, it can be inserted into a stator.The stator base body 60 can be inserted into the motor housing 62 after the electrical winding—in particular a plug-in winding—has been applied. The electric machine 10 is preferably used as a drive for an e-bike or as an actuator or rotary drive for a component in a motor vehicle, but is not limited to such applications. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2008 000 291 A1

[0002]

Claims

[1] Lamellar body (12) of an electrical machine (10), in particular an EC motor, with a plurality of individual laminations (14) which are arranged axially stacked one above the other and are connected to one another along an axial longitudinal axis (8) of the lamination body (12) by means of punched packages (20, 21, 22), wherein a plurality of different punched packages (20, 21, 22) are formed on at least one individual lamination sheet (14), wherein at least one first punched package (21) has a first bulge (41) in a first axial direction (31) and at least one second punched package (22) has a second bulge (42) in a second axial direction (32) opposite to the first axial direction (31). [2] Lamellar body (12) according to claim 1, characterized bythat the first punched packages (21) are arranged with the second punched packages (22) in the circumferential direction (9) or in the radial direction (7) alternately on the individual laminations (14). [3] Lamellar body (12) according to one of claims 1 or 2, characterized by that the lamella body (12) has an upper end lamella (15) and a lower end lamella (16) at its axial ends, and a number of middle lamellae (18) are arranged between them, wherein complete punchings (24) are formed on the upper and lower end lamellae (15, 16) as third punching packages (23). [4] Lamellar body (12) according to one of the preceding claims, characterized bythat on the lower end lamella (16) first punched packages (21) with the first bulges (41) in the first axial direction (31) alternate with the third punched packages (23) of the complete punchings (24), and on the upper end lamella (15) second punched packages (22) with the second bulges (42) in the second axial direction (32) alternate with the third punched packages (23) of the complete punchings (24). [5] Lamellar body (12) according to one of the preceding claims, characterized by that the punchings (24) of the upper end lamella (15) are arranged rotated relative to the punchings (24) of the lower end lamella (16) by exactly one punching package (20) adjacent in the circumferential direction (9). [6] Lamellar body (12) according to one of the preceding claims, characterized bythat the punched packages (20) have an elongated shape, the dimension (27) of which in the radial direction (7) is greater than the dimension (29) of which in the tangential direction (9), wherein in particular the third punched packages (23) are punched out as elongated openings (24). [7] Lamellar body (12) according to one of the preceding claims, characterized by that the laminations (14) are formed in one piece over the entire circumference, or in particular are formed as ring segments. [8] Lamellar body (12) according to one of the preceding claims, characterized by that the laminar body (12) is designed as a rotor base body (50) which can be pressed onto a rotor shaft (52), wherein recesses (54) for receiving permanent magnets are formed in particular in the laminar body (12). [9] Lamellar body (12) according to one of the preceding claims, characterized bythat the laminar body (12) is designed as a stator base body (60) which can be inserted into a stator housing (62), wherein in particular in the laminar body (12) stator slots (64) are formed for receiving an electrical winding - preferably a plug-in winding. [10] Lamellar body (12) according to one of the preceding claims, characterized by that the first and second punched packages (21, 22) are designed as beads (78) which are plastically deformed in the axial directions (31, 32) and which are pressed into the lamination sheets (14) by means of stamping dies (81, 82). [11] Lamellar body (12) according to one of the preceding claims, characterized by that the laminations (14) are punched out of electrical sheet (13) which has an axial thickness (34) of 0.2 to 0.7 mm - and preferably the axial dimension (35) of the first and second bulges (41, 42) approximately corresponds to the axial thickness (34) of the laminations (14). [12] Electrical machine (10) with a lamella body (12) according to one of the preceding claims, characterized by that the lamella body (12) is designed as a rotor base body (50) and / or stator base body (60) of an electric motor (10), wherein the electric machine (10) is preferably designed as a drive of an e-bike or as an actuator or rotary drive of a component in the motor vehicle. [13] Method for producing a lamella body (12) according to one of the preceding claims, characterized bythat when punching out the middle lamellae (18), the first punched packages (21) are formed by means of a first stamping die (81) in the first axial direction (31) and the second punched packages (22) are formed by means of a second stamping die (82) in the second axial direction (32), and when the lamella sheets (14) are axially joined together to form the lamella body (12), the first punched packages (21) are pressed into the punched through holes (24) of the upper end lamella (15) and the second punched packages (22) are pressed into the punched through holes (24) of the lower end lamella (16).

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