ROTOR FOR AN ELECTRIC RING MACHINE, CORRESPONDING RING MACHINE AND METHOD FOR PRODUCING A ROTOR

Abstract

The invention relates to an arrangement in the form of an electric ring machine in the implementation of a reluctance machine which is operated as a synchronous reluctance machine, in which recesses are formed at the outer side of the rotor sheets in the radial extension opposite to the inner barriers. These result in webs which hold and enclose the barriers and can thus be manufactured in a defined manner at both sides, even if the finished assembled rotor design is later finally mechanically reworked at the outer side. In addition to the rotor, the invention also relates to a corresponding electric ring machine and a method for producing such a rotor.

Claims

1. Rotor for an electrical ring machine in the form of a reluctance machine which is operated as a synchronous reluctance machine, comprising rotor sheets which comprise barriers, wherein recesses are formed at the outer side of the rotor sheets in the radial extension opposite to the inner barriers.

2. Rotor for an electric ring machine according to claim 1, wherein the recesses each create a barrier web of defined web thickness d, wherein the rotor has an oversize machined to its final dimension, wherein the machining has acted only on an outer thickness of the barrier extension at the outer side of the rotor away from the areas of the barrier webs.

3. Rotor for an electric ring machine according to claim 1, wherein a circumference of the outer rotor contour defined by the outer thickness of the barrier extension has an eccentricity with respect to the arrangement of the barrier webs.

4. Rotor for an electric ring machine according to claim 1, wherein the outer rotor contour is formed as an outer rotor contour machined to the final dimension, in particular an outer rotor contour machined by turning.

5. Rotor for an electric ring machine according to claim 1, wherein the electric ring machine is designed as an external or internal rotor.

6. Rotor for an electric ring machine according to claim 1, wherein the rotor sheets are designed as segmented rotor sheets and the rotor is assembled of corresponding segments.

7. Rotor for an electric ring machine according to claim 1, in which a force balance is effected in the radial direction in the double air gap by means of a double-acting arrangement of the stator design as outer and inner rotor.

8. Rotor for an electric ring machine according to claim 1, in which the rotor sheets are manufactured with an oversize which is machined after assembly.

9. Rotor for an electric ring machine according to claim 1, in which the rotor structure is manipulated by means of magnetic material in the d- and q-axis in addition to the flux guidance of the barrier structure.

10. Ring machine in the form of a reluctance machine which is operated as a synchronous reluctance machine, comprising a stator and a rotor, wherein the rotor is configured as a rotor according to claim 1.

11. Method for producing a rotor for an electric ring machine in the form of a reluctance machine which is operated as a synchronous reluctance machine, wherein the rotor comprises rotor sheets which comprise barriers, and wherein recesses are formed at the outer side of the rotor sheets in the radial extension opposite to the inner barriers, which respectively allow a barrier web of a defined web thickness d to be formed, wherein the method comprises machining an oversize of the rotor which acts only on an outer thickness of the barrier extension at the outer side of the rotor away from the areas of the barrier webs.

Description

[0021] These and other features and advantages of the present invention will become clear from the following description of various arrangements according to the invention with reference to the accompanying drawing. In the drawing:

[0022] FIG. 1 is a schematic representation of an embodiment of a rotor sheet comprising flux barriers according to the prior art with oversize and without outer recesses for the barrier webs.

[0023] FIG. 2 is a schematic representation of an embodiment of a rotor sheet comprising flux barriers according to the procedure of the invention with or without oversize and in particular comprising outer recesses for the barrier webs.

[0024] FIG. 3 is an enlarged schematic representation of the outer recesses for the barrier webs.

[0025] In the following, the use of the term electric machine or drive means both a motor-driven and a generator-driven electric machine. The term rotor 10 refers to the rotating part of the electric machine, which in the torque generating part can consist of electrical sheet or of ring sections or segments.

[0026] FIG. 1 shows a now commonplace embodiment of a rotor or rotor section of a rotor 10 or rotor sheet 12 for a synchronous reluctance machine according to the state of the art. Depending on the design, the rotor section may have an oversize in the air gap diameter or may directly have the dimension of the air gap diameter. Here, the tolerance chains of the assemblies, which result or can be achieved on the basis of the manufacturing technical design, under certain circumstances specify an oversize, which should later be machined to the desired air gap diameter after assembly. The rotor sheet 12 comprises barriers 14, 16, 18 with webs, i.e. barrier webs 20.

[0027] All manufacturing and assembly tolerances must be taken into account in the oversize so that the air gap diameter can be achieved later without removing material that is not desired, and without cutting into the open opposite to the eccentricity of the maximum tolerance position.

[0028] A rotor section of a rotor 10 for a synchronous reluctance machine is shown in FIG. 2 in a manner according to the invention.

[0029] At the outer side, i.e. at the outer side 22 (or the outer circumference), of the rotor 10 or the respective rotor sheet 12 recesses 24 are arranged there, as shown, which terminate the webs 20 of the barriers 14, 14, 18 at the outer side. This results in that the web thickness d of the barrier webs 20 (clearly visible in FIG. 3) can be preset over the circumference with or without the use of an oversize. In the case of rotors 10 with an oversize, tolerances that are always present do not result in that the tolerance is impressed in the web thickness d of the barriers 14, 16, 18 when machining the oversize. It only affects the outer thickness 26 of the barrier extension and not the sensitive area of the thin webs 20, which must saturate during operation.

[0030] Therefore, an eccentricity of the rotor sheet orientation, as may become possible with larger air gap diameters of the order of the web thickness d, does not result in a circumferential web thickness change that would exhibit in the local flux and hence also in the current.

[0031] Details of the outer recesses 24 are shown in FIG. 3. A barrier structure with three barriers 14, 16, 18 is shown, in which the outer barrier comprises a further central recess in the outer rotor contour. The outer and the central barrier 14, 16 are provided at their webs 16 at both sides with the recesses 24 according to the invention at the outer air gap side of the later air gap diameter of the machine. Thus, two recesses 20 can be found per outer barrier 14 towards the central barrier 16 and two further outer recesses 20 can be found between the central barrier 16 and the inner, third barrier 18. The recesses 24 are opposite to the inner cut-outs 28 of the barriers 14, 16, 18.

[0032] Advantageously, a defined web thickness d results despite a circumferential eccentricity of the center of the barrier structure due to manufacturing and assembly tolerances.

[0033] In particular, a design by use of rotor segment elements becomes possible in the first place, which would otherwise lead to poor operating conditions of the electric machine due to the assembly tolerances. This allows to build machines with larger air gap diameters at low cost.

[0034] The recesses 24 and the barriers 14, 16, 18, or the rotor sheets 12 can be manufactured by means of cutting processes or separation processes. Laser cutting, punching or eroding are explicitly appropriate.

[0035] When the recesses are used according to the invention and the outer surfaces are subsequently machined, an edge effect of the sheet metal production which is harmful in the sense of flux guidance leads to a permanent influence on the web edges in the recesses and thus to an influence of the edge effects on the thin webs at both sides. The machined surfaces of the rotor at the air gap to the stator, however, are “exposed” and then remain magnetically damaged to a lesser extent and then largely correspond to the base material. Thus, in an additionally effective manner, the flux guidance in the webs is more impeded compared to the surrounding air gap area, which leads to an improved machine behavior.

[0036] In a manner according to the invention, the additional structuring of the rotor shell surface by the recesses promotes the air circulation in the air gap.

[0037] The pure rear-side cooling of now commonplace modern radial flux machines is less optimal than in the side area and in the air gap due to the heat transport from the air gap and winding area up to the rear side of the sheet packet. Within a radially enclosed air gap, air exchange is also considerably reduced. At the same time, however, the strongly swirled gap flow has an extremely high heat transfer, which is not utilized because the air cannot be transported out of the circumferential air gap. Here, according to the invention, due to the recesses at the webs a considerably faster air exchange takes place out of and into the air gap. In combination with the necessary inclination of the rotor packages in order to reduce the typical torque ripple of the barrier structure, this results in an improved axial air exchange in the air gap and its air guidance.

[0038] The rotor design according to the invention allows a segmented design to be implemented, which can be used for steps in size without the need to accordingly enlarge the rotor rings as a full profile when the air gap diameter increases. According to the invention the rotor profile can be segmented and the added tolerances are less significant.

[0039] The thus simplified enabled segmented design of the ring-shaped reluctance machine thus enables a modularization of the production means in accordance with the invention. The basically similar design of a pole geometry moreover enables a modular methodology and a modular construction in terms of scalability to several capacity ranges and torque classes, despite the same manufacturing technology and manufacturing sequence. Waste is reduced to a considerable extent and, even for very large rotor diameters, the segmented design enables a series production of the individual sheets according to today's standards, despite the individual construction of the motors or their modules.

[0040] Wheel drives, fan wheels, fan rollers, rotary tables, tube mills, tube furnaces, wind turbines and turbomachines can be manufactured within a wide capacity range on smaller production machines and reduced to a complete modular system in terms of production technology.

[0041] Although the invention has been illustrated and described in detail with respect to the preferred exemplary embodiment, the invention is not limited by the disclosed examples and within the scope of the invention other variations may be derived therefrom by those skilled in the art.

[0042] For example, the construction of the recesses can also be applied to external rotors in an inverted design.

REFERENCE SYMBOLS

[0043] 10 rotor [0044] 12 rotor sheet [0045] 14 barrier [0046] 16 barrier [0047] 18 barrier [0048] 20 barrier web [0049] 22 outer side [0050] 24 recess [0051] 26 outer thickness [0052] 28 inner cut-out [0053] d web thickness