CORE DISC OR LAMINATED CORE FOR A ROTOR OF AN ELECTRIC MOTOR

Abstract

A core disc or a laminated core having at least two core discs for a rotor of an electric motor may include an inner lateral surface and at least one radial recess for receiving adhesive arranged on the inner lateral surface.

Claims

1. A core disc or a laminated core having at least two core discs for a rotor of an electric motor, comprising: an inner lateral surface; and at least one radial recess for receiving adhesive arranged on the inner lateral surface.

2. The core disc or laminated core according to claim 1, wherein the at least one radial recess has a radial depth of 0.05 mm to 0.7 mm.

3. The core disc or laminated core according to claim 1, wherein the at least one radial recess is configured as at least one of a punched recess, a milled recess, a stamped recess, and a jet-machined recess.

4. A rotor of an electric motor, comprising: a main shaft; at least one of a drive flange and a balancing disc; and a laminated core with at least two core discs according to claim 1; and wherein at least one core disc of the at least two core discs is radially bonded to the main shaft.

5. The rotor according to claim 4, wherein the at least one of the balancing disc and the drive flange is at least one of bonded, welded, and pressed to the main shaft.

6. The rotor according to claim 4, wherein at least one core disc of the at least two core discs is connected to the main shaft via a shrink-bonding fit.

7. The rotor according to claim 4, further comprising an electrical insulating layer arranged between the main shaft and the laminated core.

8. The rotor according to claim 4, wherein: the main shaft is hollow; the drive flange includes an axial extension having an outer diameter complementarily to an inner diameter of the main shaft; the axial extension engages in the main shaft; the drive flange further includes a collar, which axially lies against the main shaft and against an adjacent core disc of the at least two core discs; and the collar is bonded to at least one of the main shaft and the adjacent core disc.

9. The rotor according to claim 4, wherein at least one core disc of the at least two core discs is configured such that an inner diameter of the inner lateral surface is smaller than an associated outer diameter of the main shaft.

10. The rotor according to claim 9, wherein the inner diameter of the inner lateral surface of the at least one core disc is 0.005 mm to 0.20 mm smaller than the outer diameter of the main shaft.

11. An electric motor, comprising a rotor according to claim 4.

12. The core disc or laminated core according to claim 1, wherein the at least one radial recess has a radial depth of 0.2 mm.

13. A laminated core for a rotor of an electrical motor, comprising at least two core discs, at least one core disc of the at least two core discs including: an inner circumferential surface; and at least one adhesive receptacle projecting radially into the inner circumferential surface.

14. The laminated core according to claim 13, wherein the at least one adhesive receptacle has a radial depth of 0.5 mm to 0.7 mm.

15. The laminated core according to claim 14, wherein the at least one adhesive receptacle has a radial depth of 0.2 mm.

16. The laminated core according to claim 13, wherein the at least one adhesive receptacle includes a plurality of adhesive receptacles disposed spaced apart from one another in a circumferential direction.

17. A rotor for an electrical motor, comprising: a laminated core including at least two core discs; the at least two core discs each including: an inner circumferential surface; and at least one recess projecting radially into the inner circumferential surface; a main shaft; a drive flange; a balancing disc; and adhesive disposed at least partially within the at least one recess of each of the at least two core discs; wherein the laminated core is radially bonded to the main shaft via the adhesive.

18. The rotor according to claim 17, wherein the at least one recess includes a plurality of recesses disposed spaced apart from one another in a circumferential direction.

19. The rotor according to claim 17, wherein the adhesive includes an anaerobic adhesive film.

20. The rotor according to claim 19, wherein the laminated core is connected to the main shaft via a shrink-bonding fit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] There it shows, in each case schematically,

[0020] FIG. 1 shows a longitudinal section through a rotor according to the invention with core discs according to the invention,

[0021] FIG. 2 shows an axial front view of a core disc of a laminated core for such a rotor according to the invention.

DETAILED DESCRIPTION

[0022] According to FIG. 1, a rotor 1 according to the invention of an electric motor 2 which is not otherwise shown in more detail, comprises a main shaft 3 which in this case is formed as a hollow shaft, and a drive flange 4 and a balancing disc 5. Between the balancing disc 5 and the drive flange 4, laminated cores 6 with individual core discs 7 (see in particular FIG. 2) are arranged on an outer lateral surface of the main shaft 3. Here, the rotor 1 is rotatably mounted in the electric motor 2 about an axis 8. According to the invention, at least one radial recess 10 for receiving adhesive is now provided on an inner lateral surface 9, by way of which it is possible to fix the core discs 7 or laminated cores 6 on the outer lateral surface of the main shaft 3 via a bonded connection 13.

[0023] Compared with previously known connecting techniques that are complicated in terms of manufacture and thus also expensive to produce, for example by way of a slot-and-key connection, a simple bonding can make possible a significant reduction of the effort and thus a significant reduction of the costs.

[0024] Purely theoretically it is also conceivable that the at least one radial recess 10 for receiving adhesive can only be introduced after an assembly into a laminated core 6. In this case, the individual core discs 7 initially have no radial recess 10.

[0025] The at least one radial recess 10 has a radial depth t of 0.05 mm≤t≤0.7 mm, in particular a radial depth t of t approximately 0.2 mm. Such a depth t is sufficient in order to create a necessary adhesive gap and receive sufficient adhesive for a reliable bonded connection 13. The at least one radial recess 10 can be produced for example by means of punching, milling, stamping or jet-machining*, as a result of which not only a cost-effective but at the same time a high-quality manufacture is possible.

[0026] Since with adhesives there is an ideal adhesive thickness, the same can be easily predetermined by choosing the radial depth t of the axial recesses 10. The core discs 7 can be firmly pressed onto the main shaft 3 and the radial recesses 10 ensure the adhesive gap and thus the adhesive thickness.

[0027] At least one core disc 7 can also be embodied so that its inner diameter is smaller than an outer diameter of the main shaft 3. For example, an inner diameter of at least one core disc 7 can be 0.005 mm to 0.20 mm smaller than an outer diameter of the main shaft 3. By way of this, a reliable press fit can be ensured.

[0028] Viewing FIG. 1 further it is noticeable that the main shaft 3 is formed hollow and the drive flange 4 comprises an axial extension 11, whose outer diameter is formed complementarily to an inner diameter of the main shaft 3 and which, with mounted rotor 1, engages in the main shaft 3. In addition, the drive flange 4 has a collar 12 which, with mounted rotor 1, axially lies against the main shaft 3 and against an adjacent core disc 7 and can be bonded for example to the main shaft 3 and/or to the adjacent core disc 7 for increasing a transmittable torque. In the same way, a collar 12a of the balancing disc 5 can obviously also be bonded to the adjacent core disc 7. A fixing of the drive flange 4 via its axial extension 11 engaging in the main shaft 3 can likewise take place via a bonding, in addition or alternatively obviously also by way of a pressing or welding.

[0029] At least one core disc 7 can also be embodied so that an inner diameter Di of the inner lateral surface 9 is smaller than an associated outer diameter DA of the main shaft 3, as a result of which a press fit is created. Here, the inner diameter Di of the inner lateral surface 9 of at least one core disc 7 can be at least 0.005 mm to 0.20 mm smaller than the outer diameter DA of the main shaft 3.

[0030] Between the main shaft 3 and the laminated cores 6, an electrical insulating layer 14 can be additionally arranged in order to electrically insulate the laminated core 6 against the main shaft 3.

[0031] In a further advantageous embodiment of the rotor 1 according to the invention, at least one core disc 7 is connected to the main shaft 3 via a shrink-bonding fit. Such a shrink-bonding fit offers the major advantage of combining a thermal joining method with a bonding method. By heating the core discs 7 or the laminated cores 6 and/or cooling the main shaft 3, a radial gap can be created between the inner lateral surface 9 of the core discs 7 and the outer lateral surface of the main shaft 3 that is so large that when sliding the core disc 7 onto the main shaft an undesirable wiping-off in particular of an anaerobic adhesive during the assembly can be prevented. By way of a subsequent temperature equalisation, the core discs 7 contract and the main shaft 3 expands as a result of which the thermal joining fit is established. In the case of a shrink-bonding fit, an inner diameter of the laminated cores 6 or of the core discs 7 can be embodied so that during the thermal joining an adequate gap is created so that the laminated cores 6 can be joined without force and without substantial damage to the adhesive film or the electrical insulating layer 14. By way of such a shrink-bonding it is possible to connect the laminated cores 6 to the main shaft 3 with a sufficient force fit and at the same time realise the insulating layer 14 between the laminated cores 6 and the main shaft 3. By way of such an adhesive connection 13 between the laminated cores 6 and the outer lateral surface of the main shaft 3, higher manufacturing inaccuracy and dimensional inaccuracies can be additionally tolerated as a result of which producing the rotor 1 according to the invention does not only become simpler in terms of manufacturing but also more cost-effective.

[0032] The electrical insulating layer 14 also has a positive effect in particular on a magnetic field, as a result of which the electric motor 2 achieves a greater efficiency.

[0033] All in all, a fastening of the core disc 7 or of the laminated cores 6 on the main shaft 3 of the rotor 1 can take place with the core discs 7 according to the invention, the rotor 1 according to the invention and the electric motor 2 without the disadvantages known to date from the prior art.