METHOD FOR PRODUCING A SHEET METAL PART

Abstract

A method for producing a sheet metal part for a laminated core of a rotor of an electric motor, a sheet metal part, and a rotor are disclosed. The method includes punching out the sheet metal part from a sheet metal strip to provide at least two recesses and at least two rotor webs; and forming an elevation at least in one region that protrudes out of the sheet metal part with respect to a sheet metal part plane.

Claims

1. A method for producing a sheet metal part for a laminated core of a rotor of an electric motor, comprising: punching a sheet metal strip to provide at least two recesses and at least two rotor webs, and forming an elevation at least in one region protruding out with respect to a sheet metal part plane.

2. The method according to claim 1, wherein punching the sheet metal strip including forming the at least two rotor webs to provide linkages to the elevation obliquely protruding out of the sheet metal part plane.

3. The method according to claim 2, wherein punching the sheet metal strip provides at least three rotor webs, and the elevation is connected to the sheet metal part plane via the at least three rotor webs, and wherein the elevation forms a parallel plane to the sheet metal part plane.

4. The method according to claim 3, wherein at least one of the at least three rotor webs extends in a radial direction of the sheet metal part, and at least two other of the at least three rotor webs are arranged on an outer circumferential region.

5. The method according to claim 1, wherein the at least one region is formed as an at least partial annular channel.

6. The method according to claim 5, wherein the at least partial annular channel is rounded, triangular or trapezoidal in a cross-section.

7. The method according to claim 5, wherein the at least one region includes two partial annular channels with different radii.

8. The method according to claim 1, further comprising compressing the sheet metal part during or after the forming.

9. A sheet metal part, comprising: at least two recesses and at least two rotor webs; and an elevation disposed in at least one region protruding out with respect to a sheet metal part plane.

10. A rotor of an electric motor, comprising: a plurality of sheet metal parts stacked onto one another and connected to one another, wherein the plurality of sheet metal parts include: at least two recesses and at least two rotor webs; and an elevation disposed in at least one region protruding out with respect to a sheet metal part plane; magnets or wires arranged in the at least two recesses of the plurality of sheet metal parts.

11. The rotor according to claim 10, wherein the at least two rotor webs of at least one of the plurality of sheet metal parts provide linkages to the elevation, and wherein the at least two rotor webs obliquely protrude from the sheet metal part plane.

12. The rotor according to claim 10, wherein the at least two rotor webs of at least one of the plurality of sheet metal parts include three rotor webs, and wherein the elevation forms a parallel plane to the sheet metal part plane.

13. The rotor according to claim 12, wherein one of the three rotor webs extends in a radial direction of the at least one sheet metal part, and two other of three rotor webs are arranged on an outer circumferential region.

14. The rotor according to claim 10, wherein the at least one region is structured as an annular channel.

15. The rotor according to claim 14, wherein the annular channel has a cross-section that is rounded, triangular, or trapezoidal.

16. The sheet metal part according to claim 9, wherein the at least two rotor webs provide linkages to the elevation, and wherein the at least two rotor webs obliquely protrude from the sheet metal part plane.

17. The sheet metal part according to claim 9, wherein the at least two rotor webs include three rotor webs, and wherein the elevation forms a parallel plane to the sheet metal part plane.

18. The sheet metal part according to claim 17, wherein one of the three rotor webs extends in a radial direction, and two other of three rotor webs are arranged on an outer circumferential region.

19. The sheet metal part according to claim 9, wherein the at least one region is structured as an annular channel.

20. The sheet metal part according to claim 19, wherein the annular channel has a cross-section that is rounded, triangular, or trapezoidal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] It shows, in each case schematically,

[0018] FIG. 1 and extract of a sheet metal part according to the invention for a laminated core of a rotor of an electric motor in a first embodiment,

[0019] FIG. 2 an extract of a laminated core for a rotor of an electric motor produced from multiple sheet metal parts according to the invention,

[0020] FIG. 3 different view of a further possible embodiment of the sheet metal part according to the invention,

[0021] FIG. 4 to FIG. 6 representations each analogous to FIG. 3, however each with different embodiment.

DETAILED DESCRIPTION

[0022] According to FIGS. 1 to 6, a sheet metal part 1 according to the invention for a laminated core 2 (see FIG. 2) of a rotor 3 of an electric motor 4 comprises at least two recesses 5 for magnets and at least two rotor webs 6a, 6b and 6c. The sheet metal part 1 according to the invention is initially punched out of a flat sheet metal strip and during the punching or thereafter formed in at least one region 7 so that an elevation 9 protruding out of a sheet metal part plane 8 is created. As described here, this elevation 9 can have many different embodiments and can also be negative.

[0023] Viewing for example the embodiment of the sheet metal part 1 according to FIGS. 1 and 2, the rotor webs 6a, 6b and 6c there are formed so that these form links to the elevation 9 protruding obliquely out of the sheet metal plane 8. In this case, the elevation 9 lies on a plane that is spaced apart parallel to the sheet metal part plane 8.

[0024] Through the rotor webs 6a, 6b and 6c obliquely protruding from the sheet metal part plane 8 and the elevation 9, a strengthening of the entire sheet metal part 1 can be achieved as a result of which higher rotational speeds are possible. At the same time, the obliquely oriented rotor webs 6a, 6b, 6c also influence the magnetic properties in that these are lengthened and plasticised without the outer diameter of the sheet metal part 1 changing. Through the plasticisation, the strength of the rotor webs 6a, 6b, 6c increases, causing the rotational speed stability to be raised. Apart from this, the magnetic permeability in the region of the rotor webs 6a, 6b, 6c is reduced and the stray field thus diminished which leads to an increase of the torque.

[0025] Viewing FIGS. 1 and 2, but also FIGS. 3 to 6 further it is noticeable that a rotor web 6a extends in the radial direction 10 of the sheet metal part 1 while the two rotor webs 6b and 6c are arranged on an outer circumferential region and accordingly extend in the circumferential direction 11. Here, the rotor webs 6a, 6b and 6a and 6c respectively as well as the sheet metal part 1 in the component plane 8 and the sheet metal part 1 in the elevation 9 delimit the recesses 5 in which for example magnets or wires of coils are arranged.

[0026] The sheet metal part 1 according to FIGS. 3a and 3b comprises rotor webs 6a, 6b and 6c lying in the component plane 8, wherein the at least one formed region 7 is formed in the manner of an at least partial annular channel 12 with triangular cross-section. Viewed from the other side, this channel 12 is a bead. By way of this, a bead-like stiffening of the sheet metal part 1 can take place as a result of which the same likewise gains stiffness. The channel 12 increases the stiffness of the rotor 3. The channel 12 or generally a bead is present in order to introduce compressive stresses into the rotor webs 6a, 6b, 6c which then increase the rotational speed stability.

[0027] Viewing the sheet metal part 1 shown according to FIG. 4, the same likewise comprises a channel 12 as formed region 7 (negative elevation 9), wherein however the radial extent of this channel 12 is significantly greater than the radial extent of the channel 12 according to FIG. 3, 5 or 6. Here, the recesses 5 also run obliquely to the radial direction 10.

[0028] In the sheet metal parts according to FIGS. 5a and 5b, a formed region 7 in the manner of a partial annular channel 12 is likewise noticeable which lies radially within the recesses and does not run, like the regions 7 in the sheet metal parts 1 according to FIGS. 3 and 4, through the recesses 5. In addition, the channel 12 according to FIGS. 5a and 5b has a rounded cross-section or channel base.

[0029] On the sheet metal part 1 according to FIGS. 6a and 6b, two formed regions 7 are noticeable which are arranged spaced apart from one another in the radial direction, wherein the radially outer region 7 likewise comprises a channel 12, however with a trapezoidal cross-section. This channel 12 in turn likewise runs through the recesses 5. However, the recesses 5 extend also in a middle region 13 which lies at the height of the component plane 8. Radially within the middle region 13, a formed region 7 is again noticeable. The same merges from the middle region 13, via a slope 14, into the radial inner region 15.

[0030] Besides the forming substantially orthogonally to the component plane 8 for producing the elevations 9 which, viewed conversely, can obviously also represent depressions, an compression of the sheet metal part 1 during or after the forming, in particular against the radial direction 10 can also take place, wherein residual compressive stresses are applied to the sheet metal part 1 which in turn increase the component strength. Upon a rotation of the rotor 3 the residual compressive stresses applied against the radial direction 10 have to be compensated for by centrifugal forces in order to exert tensile forces on the sheet metal part 1 thereafter.

[0031] The sheet metal part 1 can be comparatively easily produced by punching and forming, wherein the advantages that can be achieved by forming the region 7 and producing an elevation 9 are astonishing. These advantages lie in particular in an increased strength and stiffness as well as in a reduction of the magnetic permeability in the region of the rotor webs 6a, 6b, 6c. By increasing the strength, a higher rotor rotational speed with same web size can be achieved or a smaller web size used with the same rotational speed and thus the torque increased or the use of magnet material reduced.

[0032] With such a sheet metal part 1, which in FIGS. 1 to 6 is merely shown circular segment-like but which is usually formed disc-shaped and circular in shape, the advantages described for the individual sheet metal part 1 can also be applied to a rotor 2 equipped with such sheet metal parts 1 and to an electric motor 3 equipped with such a rotor 2.