Rotor for an outer rotor motor

Abstract

The utility model relates to a rotor for an outer rotor motor. The rotor comprises a stack (1) made of ferromagnetic steel plates; permanent magnets (2) which are fastened in recesses on the inner side of the stack (1) by means of an adhesive (11); and a carrier (3) which has a hub for a shaft and which is fastened to the stack (1), each recess having a base with a plurality of projections (10) on which one of the permanent magnets (2) is seated, the projections (10) being made of some or all of the steel plates of the stack (1), and the adhesive (11) is filled in the groove space between the projections (10).

Description

Technical Field

[0001] The utility model relates to a rotor for an electric motor, more precisely for an external rotor motor. Background Art

[0002] In such a rotor, the permanent magnets must be fastened in a precisely positioned manner by means of an adhesive on the inner side of a stack of plates forming a short-circuit ring. Summary of the Utility Model

[0003] The object of the utility model is to provide a way to precisely position and reliably fasten the permanent magnets of a rotor for an external rotor motor at a lower cost.

[0004] This object is achieved by a rotor for an external rotor motor having the features according to the utility model. The rotor comprises: a stack made of ferromagnetic steel plates; permanent magnets fastened in grooves on the inner side of the stack by means of an adhesive; and a carrier having a hub for a shaft and fastened to the stack, wherein each groove has a bottom with a plurality of protrusions, and the permanent magnets stuck into the grooves rest on the protrusions, the protrusions being formed by some or all of the steel plates of the stack, and the adhesive filling the groove spaces between the protrusions.

[0005] In the rotor according to the utility model, the permanent magnets are stuck into grooves on the inner side of the plate stack. Each groove has a bottom with a plurality of protrusions, and one of the permanent magnets rests on these protrusions. The protrusions are here formed by some or all of the steel plates of the stack, and the adhesive fills the groove spaces between these protrusions. The protrusions form a stop for the permanent magnets and thus their precise positioning can be achieved, while the adhesive in the space between the protrusions ensures a reliable connection of the permanent magnets to the plate stack.

[0006] The protrusions can be designed as raised portions on all or some of the steel plates of the stack, for example as lugs. When the design of all the plates is the same, the raised portions of the plates generally form linear protrusions in the grooves of the stack, which protrusions extend parallel to each other in the axial direction of the plate stack. When only some steel plates (for example every second, every third or every fifth plate) have such raised portions, interrupted linear protrusions are formed at the bottom of the grooves, i.e. the permanent magnets rest in the grooves on the radial raised portions of some of the plates of the stack, and these raised portions are arranged along imaginary geometric lines which extend parallel to each other in the axial direction of the stack.

[0007] In addition to some or all of the plates of the plate stack being provided with lug-shaped protrusions, some plates (for example, exactly two plates) may also be provided with depressions that extend less deeply in the radial direction than the depressions of the other plates. When the plates are subsequently combined into a stack, the depressions of the plates form grooves into which the permanent magnets are glued. The depressions with a smaller depth cause the plates involved to form protrusions extending in the circumferential direction in the grooves, and these protrusions subsequently form stops for the permanent magnets in the grooves. Thus, the permanent magnets can also rest on the protrusions extending in the circumferential direction. These protrusions can be interrupted (for example, due to cuts) so that the adhesive can be well distributed on the underside of the permanent magnets.

[0008] When the protrusions are designed as protrusions on all or some of the steel plates of the stack, it is sufficient for there to be two protrusions extending parallel to each other in the axial direction in each groove, and on each of these protrusions there is respectively one of the permanent magnets. In the grooves, the space between the protrusions is filled with adhesive. When all the steel plates have corresponding protrusions, the protrusions in the grooves are continuous lines, and in other cases they are interrupted lines.

[0009] Particularly for the radial position of the top side of the permanent magnet (which top side subsequently faces its stator in an electric motor), very strict manufacturing tolerances can thus be maintained at low cost, which simplifies the manufacture of an efficient outer rotor motor.

[0010] When punching plates made of steel (such as electrical steel or other soft magnetic steel), lugs can be produced on each individual plate without high additional costs, and these lugs subsequently form protrusions extending parallel to each other in the grooves when the plates are laminated into a plate stack.

[0011] Since the plate stack has at least two linear protrusions as stops for the permanent magnets in each groove, the radial position of the permanent magnets and the thickness of the adhesive layer holding the permanent magnets can be precisely pre-given without difficulty. The associated costs are significantly lower than alternative manufacturing methods, such as using a viscous substance mixed with glass balls or ceramic balls of a defined diameter, where these balls are used as stops for the permanent magnets and the thickness of the adhesive layer can be pre-given.

[0012] The permanent magnets can be square. Square permanent magnets (such as rare earth magnets based on Nd2Fe 14 B) can be obtained relatively cost-effectively. However, permanent magnets with an arcuately curved top side and / or bottom side can also be used for the rotor according to the present utility model.

[0013] An advantageous improvement of the present utility model proposes that the grooves have side walls extending in the axial direction, and these side walls are undercut. In this way, containers can be created that can receive excess viscous substance if necessary.

[0014] Furthermore, according to a preferred provision of the present utility model, the carrier is connected to the stack by a shaft-hub connection. Furthermore, according to a preferred provision of the present utility model, the stack has on its outer side a projection extending in the axial direction, and the projection engages into a slot of the carrier. Furthermore, according to a preferred provision of the present utility model, the stack has on its outer side brackets that connect the stack to the carrier. Description of the Drawings

[0015] Other details and advantages of the present utility model are set forth in the embodiments with reference to the accompanying drawings. In the drawings:

[0016] Figure 1 a rotor for an outer rotor motor is shown, and

[0017] Figure 2 is shown Figure 1 a cut-away detail view of. Detailed Description of the Preferred Embodiments

[0018] In Figure 1 the rotor shown has a stack 1 made of ferromagnetic steel sheets, permanent magnets 2 fastened on the inner side of the stack 1, and a carrier 3 fastened on the stack 1, which carrier has a hub for a shaft (not shown). The carrier 3 can be made, for example, of aluminum or an aluminum-based alloy. The steel sheets of the stack 1 are made of electrical steel, i.e., soft magnetic steel (such as silicon steel), and are stacked on top of each other in the axial direction. Thus, the plane of each sheet extends perpendicular to the axial direction.

[0019] Figure 2 A sectional view showing details of the rotor. Figure 2 The sectional plane of

[0020] is perpendicular to the axial direction of the rotor and thus lies in the plane of the sheets or in the plane between adjacent sheets of the stack 1. As can be seen, the permanent magnets 2 are arranged in grooves on the inner side of the sheet stack 1. These grooves have a bottom 12, and two projections 10 designed as lugs of one of the sheets of the stack 1 project from this bottom. When all sheets of the stack 1 have such projections, these projections form a linear protrusion that extends parallel to each other in the axial direction. When only some sheets of the stack 1 (such as every third sheet or every seventh sheet) have such projections, the line formed by the projections is interrupted.

[0021] As Figure 2As shown, the recess has an undercut sidewall. Thus, there is a space between the undercut sidewall of the recess and the side surface of the permanent magnet 2 that can accommodate an excessive amount of adhesive 11 if necessary.

[0022] In the illustrated embodiment, the permanent magnet 2 is square, i.e., it has a flat front side, a flat rear side parallel to the front side, and flat side surfaces. Alternatively, the permanent magnet 2 can also have other shapes, such as a circularly curved front side or a circularly curved rear side.

[0023] The stack 1 has brackets 4 on its outer side, which surround both ends of the stack and preferably also surround the carrier 3. These brackets 4 can be welded to the stack by means of weld seams 5. In the illustrated embodiment, additional weld seams (not shown) can extend in the plate stack 1 to connect all the individual plates of the stack 1 to each other. However, the plates of the plate stack 1 can also be mechanically connected to each other in other ways, such as by stamping and stacking (Stanzpaketieren).

[0024] In the illustrated embodiment, the brackets 4 are arranged on the protrusions 6 of the stack 1, which extend in the axial direction on the outer side of the plate stack. Advantageously, the influence of the welding on the magnetic properties of the plates can be neglected, especially when the weld seams 5 extend only in the protrusions 6 inside the stack 1.

[0025] The protrusions 6 on the outer side of the stack 1 are also used to make a shaft-hub connection between the stack 1 and the carrier 3. The Figure 2 shaft-hub connection is shown in Figure 2 The details of the stack 1 together with the rotor carrier 3 are schematically shown in a cross-sectional view. In Figure 2 for simplicity, the brackets are not shown, the protrusions 6 of the short-circuit ring 1 engage in the slots of the carrier 3, and in this way, the transfer of torque from the stack 1 to the carrier 3 can be achieved. The slots of the carrier 3 are formed between the protrusions 8 of the carrier 3, which extend in the axial direction on the outer side of the stack 1. Thus, the slots are formed by pairs of protrusions 8 of the carrier 3, and these pairs can be seen especially in Figure 1

[0026] The protrusions 8 of the carrier 3 have protrusions 9 at the edges where they abut against the protrusions 6 of the stack 1, and thus further extend in the radial direction at this edge. The protrusions 9 are thickenings of the protrusions 8 and increase the mechanical stability of the torque transfer.

[0027] List of reference numerals

[0028] 1 Stack;

[0029] 2 Permanent magnet;

[0030] 3 Carrier;

[0031] 4 Bracket;

[0032] 5 Weld seam;

[0033] 6 Stacked protrusions;

[0034] 8 Protrusion of the carrier;

[0035] 9 Projection;

[0036] 10 Projection;

[0037] 11 Adhesive;

[0038] 12 Bottom of the groove.

Claims

1. A rotor for an outer rotor motor, the rotor comprising: A stack (1) made of ferromagnetic steel plates; a permanent magnet (2) which is fastened in a recess on the inner side of the stack (1) by means of an adhesive (11); as well as a carrier (3) having a hub for the shaft and fastened to the stack (1), Each groove has a bottom, the bottom has a plurality of protrusions (10), and the permanent magnet (2) glued into the groove sits on the protrusions. The protrusion (10) is formed from some or all of the steel sheets of the stack (1), and The adhesive (11) fills the groove spaces between the protrusions (10).

2. The rotor according to claim 1, characterized in that The protrusion (10) is formed by a projection of the steel plate.

3. The rotor according to claim 2, characterized in that The projections of adjacent steel sheets of the stack (1) form linear protrusions (10) in the groove, and the protrusions extend parallel to each other in the axial direction.

4. The rotor according to claim 2, characterized in that In each groove there are exactly two projections (10) which extend parallel to one another in the axial direction.

5. The rotor according to any one of claims 1 to 4, characterized in that The groove has a side wall extending in the axial direction, the side wall being undercut.

6. The rotor according to any one of claims 1 to 4, characterized in that The permanent magnet (2) is square.

7. The rotor according to any one of claims 1 to 4, characterized in that The carrier (3) is connected to the stack (1) via a shaft-hub connection.

8. The rotor according to any one of claims 1 to 4, characterized in that The stack (1) has, on its outer side, projections (6) extending in the axial direction, which engage in slots in the carrier (3).

9. The rotor according to any one of claims 1 to 4, characterized in that The stack (1) has a support (4) on its outer side, which connects the stack (1) to the carrier (3).

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