ROTOR AND ELECTRICAL MACHINE

Abstract

The disclosure relates to a weight-optimized, meridian-accelerated rotor including permanent magnets securely supplied with a required cooling during use. The disclosure further relates to a corresponding electrical machine, in which the problem of demagnetization of existing permanent magnets due to rotor temperatures that are too high is avoided. The rotor or the rotor of an affected electrical machine has an annular structure on the outside radius for receiving the permanent magnets. The rotor also has a conical hub structure on an inside radius and a plurality of at least rib-shaped or blade-shaped structures between the annular structure and the conical hub structure in order to form a mechanical connection of the annular structure and conical hub structure.

Claims

1. A rotor having a preferred direction of rotation, the rotor comprising: an annular structure arranged at an outer radius of the rotor; permanent magnets mounted within the annular structure; a conical hub structure arranged at an inner radius of the rotor, wherein the conical hub structure is a conical inner ring having a diameter that increases in the axial direction; and a plurality of rib-shaped or blade-shaped structures configured to mechanically connect the annular structure and the conical hub structure, wherein the plurality of rib-shaped or blade-shaped structures is provided between the annular structure and the conical hub structure, therein providing a blade duct through which ambient air flows when the rotor rotates in the preferred direction of rotation, wherein an outer boundary of the flowed-through blade duct is cylindrical and has a constant diameter.

2. The rotor of claim 1, wherein the annular structure at the outer radius of the rotor is an outer ring.

3. The rotor of claim 1, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of fan blades.

4. The rotor of claim 1, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of non-profiled or profiled fan blades.

5. The rotor of claim 1, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of planar fan blades.

6. The rotor of claim 1, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of profiled fan blades of a meridian-accelerated axial blower.

7. The rotor of claim 1, wherein the plurality of rib-shaped or blade-shaped structures is configured to be optimized for a blower with respect to the preferred direction of rotation of the rotor.

8. The rotor of claim 1, wherein one or more of the annular structure, the conical hub structure, or the plurality of rib-shaped or blade-shaped structures is hollow, with or without a particular heat-conducting phase-change medium arranged therein.

9. An electrical machine configured as a meridian-accelerated axial blower, the electrical machine comprising: a stator; and a rotor having a preferred direction of rotation, the rotor comprising: an annular structure arranged at an outer radius of the rotor; permanent magnets mounted within the annular structure; a conical hub structure arranged at an inner radius of the rotor, wherein the conical hub structure is a conical inner ring having a diameter that increases in the axial direction; and a plurality of rib-shaped or blade-shaped structures configured to mechanically connect the annular structure and the conical hub structure, wherein the plurality of rib-shaped or blade-shaped structures is provided between the annular structure and the conical hub structure, therein providing a blade duct through which ambient air flows when the rotor rotates in the preferred direction of rotation, wherein an outer boundary of the flowed-through blade duct is cylindrical and has a constant diameter.

10. The rotor of claim 2, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of fan blades.

11. The rotor of claim 2, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of non-profiled or profiled fan blades.

12. The rotor of claim 2, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of planar fan blades.

13. The rotor of claim 2, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of profiled fan blades of a meridian-accelerated axial blower.

14. The rotor of claim 2, wherein the plurality of rib-shaped or blade-shaped structures is configured to be optimized for a blower with respect to the preferred direction of rotation of the rotor.

15. The rotor of claim 2, wherein one or more of the annular structure, the conical hub structure, or the plurality of rib-shaped or blade-shaped structures is hollow, with or without a particular heat-conducting phase-change medium arranged therein.

16. The rotor of claim 15, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of fan blades.

17. The rotor of claim 15, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of non-profiled or profiled fan blades.

18. The rotor of claim 15, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of planar fan blades.

19. The rotor of claim 15, wherein the plurality of rib-shaped or blade-shaped structures is a plurality of profiled fan blades of a meridian-accelerated axial blower.

20. The rotor of claim 15, wherein the plurality of rib-shaped or blade-shaped structures is configured to be optimized for a blower with respect to the preferred direction of rotation of the rotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] There follows a more detailed explanation of exemplary embodiments, with reference to the drawings, in which:

[0024] FIG. 1 depicts a meridian-accelerated rotor according to an embodiment, in a three-dimensional perspective schematic drawing seen from the front.

[0025] FIG. 2 depicts a rear view of the rotor of FIG. 1.

[0026] FIG. 3 depicts a diagrammatic illustration of a longitudinal section through the rotor of FIG. 1.

[0027] FIG. 4 depicts a diagrammatic illustration of a longitudinal section through the rotor of FIG. 1, in a configuration according to what is referred to as the heat pipe principle.

DETAILED DESCRIPTION

[0028] In the following, FIGS. 1 to 4 will be described simultaneously.

[0029] The structure of the rotor 1 may be split into three sections 2, 3, 4.

[0030] In a first section 2, there is arranged, on an outer radius 5 of the rotor 1, an annular structure 6 for receiving permanent magnets 7 that are not explicitly depicted in FIGS. 1 and 2. In the present exemplary embodiment, this annular structure is formed by an outer ring 8.

[0031] In a second section 3, a conical hub structure 10 (see FIGS. 1, 3) is arranged on an inner radius 9. In the present exemplary embodiment, the conical hub structure 10 is formed by a conical inner ring 11 (see FIG. 2).

[0032] A multiplicity of rib-shaped or blade-shaped structures 12 for mechanically connecting the outer and inner rings 8, 11 are arranged in a third section 4 between the outer and inner ring 8, 11. In the present exemplary embodiment, these structures 12 include fan blades 13. That is to say that, at a suitable location, the mechanical connecting structures are simultaneously used not only for the mechanical integrity of the mechanical structural parts, but also equally for improving the discharge of lost heat.

[0033] Owing to the design of the rotor 1 with the stated three sections, there is arranged between the annular structure 6 and the conical hub structure 10 a blade duct through which ambient air flows when the rotor 1 rotates in its assigned preferred direction of rotation. The outer boundary of the flowed-through blade duct is cylindrical, that is to say that it has a constant diameter. The conical hub has a diameter that increases in the axial direction.

[0034] With the outer boundary being cylindrical, and if the relative velocities w.sub.1 and w.sub.2 at the inlet and the outlet are equal, w.sub.1=w.sub.2, then the outer flow line has constant pressure, that is to say that the rotor 1 generates only kinetic energy. Accordingly, the flow lines closer to the hub experience greater acceleration. For that reason, the rotor 1 described here is said to be meridian-accelerated.

[0035] The advantages of this design lie in the fact that the heat transfer in the blade ducts is maximized, and also it is possible to dispense with profiling of the fan blades.

[0036] Lost power of the rotor 1 is conveyed by thermal conduction from the outer ring 8 into the fan blades 13 and, to a lesser extent, into the inner ring 11. By virtue of the shape of the fan blades 13, when the permanent magnet rotor, (this being an alternative designation for the rotor 1), is in rotation, cooling air, as mentioned in the introduction, is pumped from an intake side to a discharge side.

[0037] A rotor 1 as depicted in FIGS. 1 to 4 is, as mentioned, a meridian-accelerated rotor 1. It rotates about a stator 14 (as suggested in FIGS. 1 to 4). The rotor 1 is a meridian-accelerated rotor 1 because the flow lines of the medium flowing through the rotor experience greater acceleration closer to the hub. Rotors 1 of this kind have a preferred direction of rotation.

[0038] An advantageous embodiment for such a preferred direction of rotation is that of a meridian-accelerated axial blower having non-decelerated relative velocity of the flow in the blade ducts, w.sub.1=w.sub.2. This makes it possible to dispense with the profiling of the fan blades 13.

[0039] In the rotating reference system, there is a relative velocity between the fan blades 13 and the pumped air. Because the fan blades 13 simultaneously serve as ribs of a plate heat exchanger, or rotating plate heat exchanger, now acting here, the lost heat of the rotor 1 is lost effectively by convection to the pumped air or the surrounding fluid, because there is a large surface area and a high relative velocity.

[0040] The heat transfer capacity or cooling capacity of the rotor 1 is further optimized by making the internal structures 15 of the outer and inner ring 8, 11, and of the fan blades 13, hollow rather than solid. A phase-change medium 16, which by the liquid-gaseous phase transition improves the transport of heat from the hot permanent magnets 7 as heat source (e.g., evaporation) to the well-cooled surfaces 17 of the fan blades 13 and of the outer and inner rings 8, 11 (e.g., condensation), may be introduced into these internal structures 15. This heat exchanger principle is also known as the heat pipe principle. The centrifugal forces acting in this context further reinforce this effect.

[0041] All in all, FIGS. 1 to 4 depict a rotor 1, or a permanent magnet rotor, in which its aerodynamically optimized supporting structure simultaneously serves as a rotating plate heat exchanger. The shaping of the outer and inner rings 8, 11, and of the fan blades 13 connecting these, is constructed in such a way that it is well suited to the specific requirements of effective rotor cooling, and specifically so as to produce separation-free axial incident flow to the rotor cooling ducts in the rotating reference system. This results in improved cooling action with lower noise generation. The achieved flow conditions in the blade ducts of the rotor 1 result in a very effective use of material, that is to say that the ratio of discharged lost power to the mass of the rotor is favorable. Implementing the so-called heat pipe principle additionally increases the effectiveness of the cooling.

[0042] When such a rotor 1 is used in corresponding electrical machines, the power density of the electrical machine in question is advantageously increased.

[0043] Although the disclosure has been illustrated and described in detail by the exemplary embodiments, the disclosure is not restricted by the disclosed examples and the person skilled in the art may derive other variations from this without departing from the scope of protection of the disclosure. It is therefore intended that the foregoing description be regarded as illustrative rather than limiting, and that it be understood that all equivalents and/or combinations of embodiments are intended to be included in this description.

[0044] It is to be understood that the elements and features recited in the appended claims may be combined in different ways to produce new claims that likewise fall within the scope of the present disclosure. Thus, whereas the dependent claims appended below depend from only a single independent or dependent claim, it is to be understood that these dependent claims may, alternatively, be made to depend in the alternative from any preceding or following claim, whether independent or dependent, and that such new combinations are to be understood as forming a part of the present specification.