Multi-part rotor body for a rotor of a synchronous machine

Abstract

A rotor body for an electric machine rotor is described, wherein the rotor body comprises a base body having a central opening for receiving a rotor shaft. The base body has a plurality of contact surfaces arranged uniformly around the central opening in the circumferential direction. The rotor body comprises a plurality of pole bodies arranged on the corresponding plurality of contact surfaces of the base body and connected to the base body, such that the base body and the plurality of pole bodies form a plurality of salient poles for arranging a corresponding plurality of winding elements of the rotor.

Description

[0001] The invention relates to an electric machine, such as a current-excited synchronous machine. In particular, the invention relates to a rotor body for a rotor of an electric machine.

[0002] A vehicle that is at least partially electrically powered includes an electric machine for propelling the vehicle. The electric machine comprises a stator that surrounds a rotor of the electric machine.

[0003] Manufacturing the windings of the (current-excited) rotor of an electric machine is typically associated with a relatively high manufacturing effort. Furthermore, it is usually difficult to produce the windings of the different pivot poles of the rotor as uniformly as possible in order to improve the efficiency of the electric machine. In addition, the rotor of an electric machine typically cannot be adapted to changing requirements.

[0004] This document addresses the technical task of enabling the efficient manufacture and / or adaptation of a rotor for an electric machine.

[0005] The problem is solved by the independent claim. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent claim, which can be made the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can constitute an invention independent of the features of the independent claims.

[0006] According to one aspect, a (multi-part) rotor body for the rotor of an electric machine, in particular a current-excited synchronous machine, is described. The rotor body comprises a base body, the base body having a central opening for receiving the rotor shaft. Furthermore, the base body has a plurality of contact surfaces arranged uniformly around the central opening in the circumferential direction. The rotor body can, for example, have N contact surfaces, with N ≥ 3, or N ≥ 4, or N ≥ 6.

[0007] The base body typically comprises a multitude of electrically conductive, mutually insulated layers (especially laminations) (e.g., 50 or more, or 100 or more layers) stacked one on top of the other along the axis of rotation of the rotor body (i.e., along the rotor shaft). The base body can, in particular, be designed as a base lamination stack.

[0008] The rotor body further comprises a plurality of pole bodies (in particular N pole bodies) which are arranged on the corresponding plurality of contact surfaces of the base body and (detachably) connected to the base body, so that a corresponding plurality of salient poles for arranging a corresponding plurality of winding elements of the rotor is formed by the base body and by the plurality of pole bodies.

[0009] The individual pole bodies can each extend radially away from the base body. Optionally, each pole body can have a leg section for arranging an (electrically conductive) winding element.

[0010] The individual pole bodies typically each have a large number of electrically conductive, mutually insulated layers (e.g., sheets) stacked on top of each other along the rotational axis of the rotor body (e.g., 50 or more, or 100 or more layers). The individual pole bodies can thus each be designed as a pole-sheet assembly.

[0011] By providing a rotor body composed of individual pole bodies and a base body, efficient adaptation of the rotor body geometry is possible. Furthermore, this allows for the efficient and high-quality provision of the rotor winding elements.

[0012] The multiple layers of the base body and the polar body can exhibit one or more distinct properties. In other words, one or more properties of the multiple layers of the base body can differ from the corresponding one or more properties of the multiple layers of the polar body. Examples of such properties are: • the layer thickness of the individual layers of the respective multitude of layers along the axis of rotation; • the number of layers of the respective multitude of layers; and / or • the material and / or a material property of the individual layers of the respective multitude of layers.

[0013] The laminated cores of the base body and the pole bodies can therefore differ from each other. This allows the properties of a rotor to be adapted to specific requirements in a particularly efficient and flexible manner.

[0014] Each pole body can be connected to the base body by means of at least one clamping wedge, which can extend along the axis of rotation from one end face to the opposite end face of the rotor body. The clamping wedge can be rigidly connected to a contact surface of the base body or to the pole body itself, which is positioned on the contact surface. Alternatively, the clamping wedge can be designed as a separate, independent component. If necessary, several clamping wedges can be used to connect a pole body to the base body. This allows for a particularly strong connection between the individual pole bodies and the base body.

[0015] Furthermore, the clamping wedge can have a multitude of electrically conductive, mutually insulated layers (e.g., sheets) stacked on top of each other along the rotational axis of the rotor body (e.g., 50 or more, or 100 or more layers). One or more of the aforementioned properties of the clamping wedge layers may differ from the corresponding one or more properties of the base body and / or the respective pole body.

[0016] By using clamping wedges to fix the individual pole bodies to the base body, a particularly efficient and reliable fixation of the individual pole bodies (with respect to forces acting in the radial direction) can be achieved.

[0017] A mounting surface of the base body and the pole body attached to the mounting surface can each have two grooves and two tongues, forming two corresponding tongue-and-groove connections (each extending along the axis of rotation from one end face to the opposite end face of the rotor body). The clamping wedge can be positioned between the two tongue-and-groove connections. Providing additional tongue-and-groove connections allows for particularly reliable fixation of the individual pole bodies to the base body.

[0018] A mounting surface of the base body or the pole body arranged on the respective mounting surface can have a recess, in particular a groove, for receiving the clamping wedge (where the recess extends from one end face to the opposite end face of the rotor body). The clamping wedge can have an opening angle that is greater than the opening angle of the recess. Furthermore, the clamping wedge and / or the recess can each have a V-shaped profile perpendicular to the axis of rotation of the rotor body. This allows for a particularly reliable fixation of the individual pole bodies to the base body.

[0019] According to another aspect, a rotor for an electric machine is described, wherein the rotor comprises a (multi-part) rotor body designed as described in this document. Furthermore, the rotor includes a plurality of electrically conductive winding elements arranged on the corresponding plurality of pole bodies of the rotor body. The individual winding elements can each be designed as independent components that have been manufactured (efficiently and with high quality) outside the rotor body.

[0020] According to another aspect, an electrical machine, in particular a (current-excited) synchronous machine, is described, which includes the rotor described in this document.

[0021] According to another aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described that includes the electric machine described in this document for propelling the vehicle.

[0022] It should be noted that the devices and systems described in this document can be used both alone and in combination with other devices and systems described in this document. Furthermore, any aspect of the devices and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways. Features listed in parentheses are to be understood as optional features.

[0023] The invention will now be described in more detail using exemplary embodiments. Fig. 1a an exemplary electric machine; Fig. 1b a perspective view of an exemplary rotor body; Fig. 1c a perspective view of an exemplary rotor with rotor coils; Fig. 2a to 2c different parts of the rotor; Fig. 3a to 3c different states during the manufacture of the rotor; and Fig. 4a and Fig. 4b the attachment of a pole body to the base body of the rotor.

[0024] As stated at the outset, this document deals with the efficient and precise manufacturing of the windings of the rotor of a (current-excited) electrical machine. In this context, it shows Fig. Figure 1a shows an exemplary electric machine 100 in a view perpendicular to the shaft 101 of the electric machine 100. The (rotor) shaft 101 of the electric machine 100 can correspond to the longitudinal axis of the stator 110 and / or the rotational axis of the rotor 120 of the electric machine 100. Furthermore, the shaft 101 can run along the z-axis of the Cartesian coordinate system shown.

[0025] The electric machine 100 comprises a stator 110 with several stator windings 111 arranged at different angular positions around the rotational axis of the rotor 120, and configured to generate a rotating electromagnetic field. The stator 110 is enclosed by a housing 135 of the electric machine 100.

[0026] Furthermore, the electric machine 100 comprises the rotor 120, which is driven by the rotating magnetic field generated by the stator 110. The rotor 120 is rigidly connected to the shaft 101 driven by the electric machine 100 (which may be connected to the rotor shaft of the rotor 120 or may be identical to the rotor shaft of the rotor 120). The rotor 120 comprises a rotor body 122.

[0027] The rotor 120 of an electric machine 100 can have as rotor body 122 an iron lamination stack (e.g. composed of mutually insulated laminations). Fig. Figure 1b shows an exemplary rotor body 122 of a rotor 120 in a perspective view. The rotor body 122 extends along the axis of rotation or the longitudinal axis of the rotor 120 from a first end face 128 to an opposite second end face 129. In the illustrated example, the rotor body 122 has different magnetic salient poles 124, which are arranged at different angular positions around the axis of rotation of the rotor 120. The salient poles 124 can be evenly distributed around the axis of rotation. Electrically conductive windings can be arranged around each of the individual salient poles 124, through which a magnetic field is generated. The individual salient poles 124 can thus form magnetic poles of the rotor 120.

[0028] The rotor body 122 has a central opening 123, in particular a bore, into which the rotor shaft 101 of the rotor 120 can be inserted. The rotor shaft 101 can be rotatably mounted on the end faces 128, 129 of the rotor body 122 via respective bearing surfaces to enable rotation of the rotor 120.

[0029] The rotor body 122 can have a central region 121 in which the central opening, in particular the bore, 123 is arranged. The central region 121 can be designed as a cylinder extending along the axis of rotation of the rotor 120 from the first end face 128 to the second end face 129. The individual salient poles 124 can each extend radially away from the central opening 123, starting from the central region 121.

[0030] Between each pair of directly adjacent salient poles 124 of the rotor body 122, a rotor slot 125 is formed, in which the windings of the adjacent salient poles 124 are arranged. A rotor slot 125 extends along the longitudinal and / or rotational axis from the first end face 128 to the opposite second end face 129 of the rotor body 122. The rotor body 122 and the individual rotor slots 125 can each have a specific overall length 127 from the first end face 128 to the second end face 129.

[0031] The rotor groove 125 between two directly adjacent (circumferentially) salient poles 124 has an opening 126 on the outer surface of the rotor body 122 facing away from the rotor shaft 101, the opening 126 extending along the longitudinal axis from the first end face 128 to the second end face 129 of the rotor body 122. In the transverse direction to the longitudinal axis, the opening 126 is bounded by (mutually facing) legs 131 of the pole shoes 130 of the two directly adjacent salient poles 124.

[0032] To manufacture a rotor 120, electrically conductive windings 140 can be wound around the salient poles 124, so that in a rotor slot 125 windings 140 of the two directly adjacent salient poles 124 are arranged (see Fig. 1c) After arranging the windings 140, the openings 126 of the individual rotor slots 125 can each be covered with a slot closure wedge. A slot closure wedge can be inserted from an end face 128 between the legs 131 of the pole shoes 130 of the two directly adjacent salient poles 124 to cover the opening 126.

[0033] Arranging the windings 140 around the individual salient poles 124 is typically associated with a relatively high manufacturing effort. Furthermore, deviations between the windings 140 of the different salient poles 124 typically occur during their manufacture, which can cause a certain degree of running instability of the rotor 120.

[0034] Fig. Figure 2a shows an exemplary base body 200 for a rotor body 122. The base body 200 can encompass the central region 121 of the rotor body 122, or the base body 200 can correspond to the central region 121 of the rotor body 122. The base body 200 has the central opening 123 for arranging the rotor shaft 101 of the rotor 120. Furthermore, the base body 200 is designed such that a plurality of pole bodies 220 (see Figure 2a) can be attached to the base body 200. Fig. 2c) can be attached, wherein each pole body 220 can form a salient pole 124 of the rotor body 122. For this purpose, the base body 200 has one or more fastening elements 201, 202 on its outer surface for each pole body 220, by means of which the pole body 220 can be firmly connected to the base body 200.

[0035] A multi-part rotor body 122 is thus described, comprising a base body 200 which has a plurality of contact surfaces 205 for arranging a corresponding plurality of pole bodies 220. The contact surfaces 205 can be arranged uniformly around the circumference of the base body 200. Each of the individual contact surfaces 205 has one or more fastening elements 201, 202, which make it possible to arrange and fix a pole body 220 to the respective contact surface 205, in particular to fix it against centrifugal forces acting radially during the operation of the rotor 120. The rotor body 122 thus consists of the base body 200 and the plurality of pole bodies 220. In the assembled state, the following essentially results: Fig. 1b shown rotor body 122.

[0036] A polar body 220 can, as exemplified in Fig. As shown in Figure 2c, the pole body 220 has a leg section 224 extending radially from a contact surface 225 of the pole body 220 to the pole shoe 130 of the pole body 220. One or more fastening elements 222 are arranged on the contact surface 225 of the pole body 220, which are designed to be complementary to the one or more fastening elements 201, 202 of the base body 200 in order to fasten the pole body 220 to the base body 200.

[0037] The multi-part structure of the rotor body 122 makes it possible to attach winding elements 210 (see Fig. 2b) to prefabricate outside the rotor 120. This allows the windings 140 of the rotor 120 to be manufactured efficiently and to a high standard. As exemplified in Fig. As shown in Figure 3a, a pre-fabricated winding element 210 can be slid onto the leg section 224 of a pole body 220, such that the leg section 224 of the pole body 220 forms the core of the coil formed by the winding element 210. Alternatively, the leg section 224 of the pole body 220 can be wound with a conductor wire using a winding method to create the winding element 210.

[0038] The pole body 220 with the attached winding element 210 can then be rotated radially, as shown for example in Fig. 3b shown, are placed on a contact surface 205 of the base body 200, so that the one or more fastening elements 201, 202 on the contact surface 205 of the base body 200 interact with the one or more complementary fastening elements 300, 222 on the contact surface 225 of the pole body 220 in order to fix the pole body 220 with the attached winding element 210 to the base body 200.

[0039] Similarly, a plurality of pole bodies 220, each with attached winding elements 210, can be arranged and fastened to the corresponding plurality of contact surfaces 205 of the base body 200 in order to achieve the Fig. to manufacture the rotor 120 shown in 3c.

[0040] In the Fig. 4a and Fig. Figure 4b shows further details of the fastening elements 201, 202, 300, and 222. In the example shown, the one or more fastening elements 222 of a pole body 220 are each designed as springs, and the one or more fastening elements 202 of the base body 200 are each designed as grooves, so that the pole body 220 can be fastened to the base body 200 by means of one or more tongue-and-groove connections. The one or more springs and / or grooves can each extend along the axis of rotation from the first end face 128 to the second end face 129 of the rotor body 122.

[0041] It should be noted that in an alternative example, the one or more fastening elements 222 of a pole body 220 can each be designed as grooves, and the one or more fastening elements 202 of the base body 200 can each be designed as springs. A hybrid form is also possible, in which one or more fastening elements 222 of a pole body 220 are designed partly as a spring and partly as a groove, and in which one or more fastening elements 202 of the base body 200 are designed partly as a groove and partly as a spring.

[0042] Furthermore, the one or more springs and / or grooves can each have a roughened surface and / or a surface with grooves to ensure a particularly reliable connection between the pole body 220 and the base body 200.

[0043] Alternatively or additionally, at least one spring 300 can have a greater circumferential width than the corresponding groove 201. The spring 300 can, for example, have a width that decreases with increasing distance from the contact surface 225. The spring 300 can thus be designed as a clamping wedge. The clamping wedge 300 can be inserted into the corresponding groove 201, and (due to the increasing oversize of the clamping wedge 300) an increasingly strong circumferential force can be exerted by the clamping wedge 300 on the groove 201. This allows for a particularly reliable fixation.

[0044] In the Fig. 4a and Fig. In the example shown in Figure 4b, the pole element 220 and the base body 200 each have three fastening elements 201, 202, 300, 222, each having a central fastening element 201, 300, and on both sides of the central fastening element 201, 222, an adjacent fastening element 202, 222. The central fastening element 201, 300 can be configured (due to the clamping wedge 300) to exert a force in the circumferential direction, whereby this force is transmitted to the adjacent fastening elements 202, 222, and thereby further increases the reliability of the fixation.

[0045] A one-piece design of a rotor body 122 (as exemplified in Fig.The one-piece rotor lamination concept (1b) has the disadvantage that if the geometry of the lamination cut changes as a whole, the entire die or punching tool must be modified, which involves relatively high costs and a relatively high time expenditure. Furthermore, the one-piece rotor lamination concept 122 results in a relatively high amount of lamination waste, which negatively impacts the cost of the rotor body 122. Additionally, as already mentioned, accessibility to the windings 140 and the winding process are limited.

[0046] This document describes a multi-part rotor lamination stack (i.e., rotor body) 122 and the assembly of the different parts 200, 230 by clamping using wedges 300. The rotor body 122 consists of a (radially) inner core area (i.e., the base body) 200 and several (radially) outer outer segments (i.e., the pole bodies) 220, each pole advantageously being represented by an outer segment (i.e., by a pole body) 220.

[0047] Both the core section 200 and the outer segments 220 are each composed of several individual sheets. The core section 200 and the outer segments 220 can be manufactured independently of each other and can, for example, have different sheet thicknesses. The outer segments 220 can, for instance, be made of thinner individual sheets than the core section 200. Alternatively or in addition to the different thickness of the individual sheets, the outer segments 220 can have a different material composition (electrical steel sheets) and thus different mechanical and / or electromagnetic properties than the core section 200.

[0048] The multi-part design of the rotor lamination stack 122 enables pre-winding (including insulation) of the core area 200 and / or the individual outer segments 220 for the production of the winding elements 210. This pre-winding in the multi-part rotor lamination stack 122 is advantageous with regard to accessibility to the windings 140, 210 and with regard to the choice of winding method and / or the desired winding parameters (e.g., pre-tension and / or orientation of the winding system).

[0049] The described concept thus improves the winding quality (winding pattern) in terms of manufacturing technology and overall quality. The multi-part design of the rotor lamination stack 122 also has a beneficial effect on material waste and therefore on costs. Furthermore, the described clamping principle allows for joining at room temperature. This results in savings in process, material, and energy costs during manufacturing and assembly. In addition, the multi-part design of the rotor lamination stack 122 offers a simple way to adapt the geometry of the outer segments 220, e.g., with regard to the outer diameter, tooth width, height, and / or the geometry of the pole shoe 130. This allows for the testing of various variants during development according to electromagnetic and / or structural requirements, e.g., to optimize the drive system of a vehicle.

[0050] The prefabricated and insulated coils (typically copper windings), i.e., the winding elements 210, can be attached to the core area 200 or to the individual outer segments 220. Attaching them to the individual outer segments 220 has the advantage that it forms a unit consisting of the outer segment 220 and the coil 210, which is easy to handle in the logistics and assembly process and can, for example, be prefabricated.

[0051] A clamping wedge 300 can be used for clamping between the core area 200 and an outer segment 220. The clamping wedge 300, like the core area 200 and the outer segments 220, can consist of individual sheets, the thickness and material composition (electrical steel sheets) of which can correspond to those of the core area 200 or the outer segments 220. Alternatively, the individual sheets of the clamping wedge 300 can be made of a different material. This material can be highly thermally conductive or highly thermally insulating and / or highly electromagnetically conductive or highly electromagnetically insulating.

[0052] The clamping wedge 300 can be V-shaped (with a specific angle). Furthermore, the clamping wedge 300 can be wider than the central receiving opening 201 of the core area 200 of the rotor lamination stack 122. Additionally, the angle of the clamping wedge 300 can be greater than the angle of the central receiving opening 201 of the core area 200 of the rotor lamination stack 122.

[0053] The core area 200 of the rotor lamination stack 122 preferably has a central receiving opening (e.g., a recess and / or groove) 201 for the clamping wedge 300. This opening 201 can be uniformly open, i.e., parallel-flanked, or V-shaped (with a specific angle). When the clamping wedge 300 and an outer segment 220 of the rotor lamination stack 122 are radially joined, a force originating from the clamping wedge 300 (predominantly in the circumferential direction) acts on both sides and on both parts 200, 220 of the rotor lamination stack 122, and propagates through both the outer segments 220 and the core area 200. This force leads to stresses in both parts 200, 220 of the rotor lamination stack 122, causing them to deform elastically, clamp, and thus resist centrifugal force by means of self-locking. Additionally, a force acts from the windings 140, 210 in the opposite direction to the force of the clamping wedge 300, which the aboveSelf-locking is supported and thus also has a beneficial effect against slipping and / or loosening of the entire connection under centrifugal force.

[0054] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures are intended only to illustrate the principle of the proposed devices and systems by way of example.

Claims

[1] Rotor body (122) for a rotor (120) of an electric machine (100); wherein - the rotor body (122) comprises a base body (200); - the base body (200) has a central opening (123) for receiving a rotor shaft (101) of the rotor (120); - the base body (200) has a plurality of contact surfaces (205) which are arranged uniformly around the central opening (123) in the circumferential direction; and - the rotor body (122) has a plurality of pole bodies (220) which are arranged on the corresponding plurality of contact surfaces (205) of the base body (200) and connected to the base body (200), so that a plurality of salient poles (124) for arranging a corresponding plurality of winding elements (140, 210) of the rotor (120) is formed by the base body (200) and by the plurality of pole bodies (220). [2] Rotor body (122) according to claim 1, wherein - the base body (200) and a pole body (220) each have a plurality of electrically conductive, mutually insulated layers stacked on top of each other along a rotational axis of the rotor body (122); and - the multitude of layers of the base body (200) and the polar body (220) exhibit one or more different properties. [3] Rotor body (122) according to claim 2, comprising one or more different features, - a layer thickness of the individual layers along the axis of rotation; - a number of layers of the respective multitude of layers; and / or - a material and / or a material property of the individual layers. [4] Rotor body (122) according to one of the preceding claims, wherein a pole body (220) is connected to the base body (200) by means of at least one clamping wedge (300). [5] Rotor body (122) according to claim 4, wherein - a contact surface (205) of the base body (200) and the pole body (220) arranged on the contact surface (205) have two grooves (202) and two tongues (222) by which two tongue-and-groove connections are formed; and - the clamping wedge (300) is positioned between the two tongue and groove connections. [6] Rotor body (122) according to one of claims 4 to 5, wherein a contact surface (205) of the base body (200) or the pole body (220) arranged on the contact surface (205) has a recess (201), in particular a groove, for receiving the clamping wedge (300). [7] Rotor body (122) according to claim 6, wherein - the clamping wedge (300) has an opening angle that is greater than the opening angle of the recess (201); and / or - the clamping wedge (300) and / or the recess (201) each have a V-shaped profile perpendicular to an axis of rotation of the rotor body (122). [8] Rotor body (122) according to any one of claims 4 to 7, wherein - the clamping wedge (300) is firmly connected to a contact surface (205) of the base body (200) or to the pole body (220) arranged on the contact surface (205); or - the clamping wedge (300) is designed as a separate, independent component. [9] Rotor (120) for an electric machine (100); wherein - the rotor (120) comprises a rotor body (122) configured according to one of the preceding claims; and - the rotor (120) comprises a plurality of electrically conductive winding elements (210) arranged on the corresponding plurality of pole bodies (220) of the rotor body (122). [10] Rotor (120) according to claim 9, wherein the individual winding elements (210) are each designed as independent components manufactured outside the rotor body (122).

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