Rotor with clamping wedge for securing rotor windings

Abstract

The invention relates to a rotor for an electric machine, the rotor comprising a rotor body having a first salient pole and a second salient pole, by means of which a rotor groove is delimited. The rotor further comprises windings arranged in the rotor groove, and a clamping wedge which is arranged in the rotor groove and is designed to locally secure the windings within the rotor groove.

Description

[0001] Rotor with clamping wedge for fixing rotor windings

[0002] The invention relates to an electric machine, such as a synchronous machine. In particular, the invention relates to the support and / or fixing of the windings of the rotor of an electric machine.

[0003] 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.

[0004] The rotor slots of an electric machine's (current-excited) rotor are typically covered with a slot-closing wedge to create a sealed cavity within each slot. This cavity can then be filled with a potting compound to fix the windings within the individual rotor slots and / or electrically insulate them from the rotor body. The use of potting compound results in relatively high manufacturing costs and increased rotor weight. This document addresses the technical challenge of enabling a particularly efficient manufacturing process for an electric machine's rotor.

[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 dependent 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 rotor for an electric machine is described. The rotor comprises a rotor body with a first salient pole and a second salient pole, which define a rotor slot (which can also be called a pole slot), the rotor slot typically having an opening between the two salient poles. The rotor typically includes a plurality of rotor slots (e.g., N = 4 or more, or N = 6 or more). The rotor is preferably designed such that it does not contain any hardened potting compound within the individual rotor slots.

[0007] The rotor has (electrically conductive) windings arranged in at least one rotor slot. Typically, (electrically conductive) windings are arranged in each of the N rotor slots. The windings can each be arranged around a salient pole of the rotor.

[0008] The rotor further comprises a clamping wedge arranged in the rotor slot, which is designed to locally fix the windings within the rotor slot. Preferably, the rotor has a clamping wedge in each of the N rotor slots for locally fixing the windings arranged in each of the N rotor slots.

[0009] This describes a rotor that has a clamping wedge in each of its individual rotor slots for fixing the windings. This allows for reliable and efficient fixing of the windings (without the use of hardened potting compound).

[0010] The following describes possible properties of a clamping wedge for a Rotomut. The clamping wedges for the other rotor slots of the rotor can be designed accordingly.

[0011] The clamping wedge in a rotor slot is preferably designed to exert a circumferential force on the windings, so that the windings are pressed against the first or second salient pole of the rotor slot and thereby fixed in place within the rotor slot. In this way, the windings can be pressed against the (salient) poles surrounding the (rotor) slot in a particularly reliable manner and thus fixed within the rotor slot.

[0012] The clamping wedge in a rotor groove can each have a wedge body that is fastened within the rotor groove by means of at least one fastening element. The wedge body can contact the windings arranged within the respective rotor groove. The wedge body can, in particular, be designed to be elastic such that it expands circumferentially when compressed radially. The fastening element can be designed to compress the wedge body radially.

[0013] The spreading generated during radial compression fills the groove width (i.e., the cavity in the rotor groove) in the circumferential direction. This allows the windings to be fixed within the rotor groove in a particularly reliable manner. Fixing the winding wires prevents centrifugal force-induced mass displacement of the windings, thus reliably avoiding rotor imbalance.

[0014] The rotor body can extend axially from a first end face to an opposing second end face, and the rotor groove can have a specific total length from the first end face to the second end face. The wedge body of the clamping wedge can extend axially within the rotor groove from a first position to a second position. The first position is preferably spaced from the first end face of the rotor body by at most 20%, particularly by at most 10%, 5%, or 1%, of the total length of the rotor groove. Furthermore, the second position is preferably spaced from the second end face of the rotor body by at most 20%, particularly by at most 10%, 5%, or 1%, of the total length.

[0015] The wedge body can thus extend essentially completely within the rotor slot in the axial direction. This ensures a particularly reliable fixing of the windings.

[0016] The rotor wedge can have a total height extending radially from the base adjacent to the central region of the rotor body to the opening of the rotor groove. The lateral poles of the rotor body can each extend radially away from the central region of the rotor body. Furthermore, the wedge body can extend radially within the rotor groove from a lower point to an upper point. The lower point is preferably spaced from the base of the rotor groove by at most 20%, particularly by at most 10%, 5%, or 1% of the total height of the rotor groove. Furthermore, the upper point is preferably spaced from the opening of the rotor groove by at most 20%, particularly by at most 10%, 5%, or 1% of the total height.

[0017] The wedge body can thus extend almost completely within the rotor slot in the radial direction. This ensures a particularly reliable fixing of the windings.

[0018] A threaded bore can be arranged in the central area of ​​the rotor body, extending radially from the bottom of the rotor groove into the central area of ​​the rotor body. The fastening element can include a screw that is screwed into the threaded bore. The screw can extend from the opening of the rotor groove through a bore within the wedge body to the bottom of the rotor groove. The screw head can act radially on the wedge body (compressing the wedge body radially). Using a screw as the fastening element allows for particularly efficient and reliable fixing of the clamping wedge.

[0019] The clamping wedge can have several fastening elements, which are arranged one behind the other, particularly evenly spaced, along the axial direction, so that the wedge body is fastened at several points within the rotor. Each fastening element can have a screw that is screwed into a corresponding threaded hole in the rotor body. This ensures a particularly reliable fixation of the clamping wedge. Furthermore, an electric machine, in particular a (current-excited) synchronous machine, is described, which includes the rotor described in this document.

[0020] 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.

[0021] 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.

[0022] The invention will now be described in more detail using exemplary embodiments.

[0023] Figure a is an exemplary electrical machine;

[0024] Figure 1b shows a perspective view of an exemplary rotor body;

[0025] Figure 1c shows a perspective view of an exemplary slotted locking wedge;

[0026] Figure Id shows a sectional view of a slot locking wedge arranged in a rotor slot; and

[0027] Figure 2 shows an example of a clamping wedge for fixing the windings in the rotor slot of a rotor.

[0028] As stated at the outset, this document deals with the efficient and reliable fixing of the windings in the individual rotor slots of the rotor of an electric machine, in particular to enable the provision of a particularly cost-effective electric machine. In this context, Fig. 1a shows an exemplary electric machine 100 in a view perpendicular to the shaft 101 of the electric machine 100. The shaft 101 of the electric machine 100 can correspond to the longitudinal axis of the stator 110 and / or the rotation or rotor 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.

[0029] 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.

[0030] 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.

[0031] The rotor 120 of an electric machine 100 can have a laminated iron core (e.g., composed of mutually insulating sheets) as its rotor body 122. Fig. 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 salient poles 124 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. A rotor coil (i.e., windings) can be arranged around each salient pole 124, through which a magnetic field is generated. The individual salient poles 124 can thus form magnetic poles of the rotor 120.

[0032] The rotor body 122 has a central opening or recess 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 of the rotor body 122 via respective bearing surfaces to enable rotation of the rotor 120. The central recess 123 can be arranged in a central region 121 of the rotor body 122. The individual salient poles 124 can extend radially from the central region 121 and / or from the central recess 123.

[0033] 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.

[0034] The rotor slot 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. The opening 126 extends along the longitudinal axis from the first end face 128 to the second end face 129 of the rotor body 122. Perpendicular to the longitudinal axis, the opening 126 is bounded by the (mutually facing) legs 131 of the pole shoes 130 of the two directly adjacent salient poles 124. To manufacture a rotor 120, electrically conductive windings can be wound around each of the salient poles 124, such that windings from the two directly adjacent salient poles 124 are arranged in each rotor slot 125. After the windings have been arranged, the openings 126 of the individual rotor slots 125 can each be covered with a slot closure wedge.A slotted locking wedge can be inserted from an end face 128 between the legs 131 of the pole shoes 130 of the two directly adjacent leg poles 124 to cover the opening 126.

[0035] Fig. 1c shows an exemplary slot closure wedge 180, which has a covering area 186 that covers the opening 126 of a rotor slot 125. The slot closure wedge 180 can further have an insertion area 185 that extends from the covering area 186 into the rotor slot 125 when the slot closure wedge 180 covers the opening 126 of the rotor slot 125.

[0036] Following the arrangement of the slot closure wedge 180 at the openings 126 of the corresponding rotor slots 125 of the rotor body 122, the cavities 192 of the covered rotor slots 125 can each be filled with a potting compound in order to locally fix the windings 190 in the individual rotor slots 125 (see Fig. Id).

[0037] As explained at the outset, the introduction of potting compound into the cavity 192 of a Rotomut 125 involves additional manufacturing effort and results in an increased weight of the rotor 120. Fig. 2 shows a section of an exemplary rotor 120. In particular, Fig. 2 shows a rotor groove 125 of the rotor 120 between two salient poles 124. Windings 190 are arranged around each of the salient poles 124. A clamping wedge 200 is arranged in the cavity 192 between the windings 190. The clamping wedge 200 has a wedge body 201, which is fastened within the cavity 192 by a fastening element 202, in particular by a screw.

[0038] As shown in Fig. 1b, the rotor body 122 typically has a central region 121, with the individual salient poles 124 extending radially from the central region 121. The central recess 123 for arranging the rotor shaft 101 is typically located in the central region 121. The rotor body 122 can have one or more threaded bores 213 at the bottom of each of the individual rotor slots 122 (within the central region 121). The one or more screws 202 for fastening a wedge body 201 can each have a thread 203, with which the respective screw 202 is screwed into a corresponding threaded bore 213. In this way, the wedge body 201 can be efficiently and reliably fixed within the cavity 192 of a rotomut 125.

[0039] The wedge body 201 preferably extends along the axis of rotation of the rotor shaft 101 from the first end face 128 to the opposite second end face 129 of the rotor body 122. Several fastening elements 202, in particular screws, can be arranged one after the other along the axis of rotation to fix the wedge body 201.

[0040] The wedge body 201 preferably extends radially from the central body 121, i.e., from the bottom of a rotor slot 125, to the opening 126 of the rotor slot 125. This ensures a particularly reliable fixing of the windings 190.

[0041] The wedge body 201 is preferably designed such that it exerts a circumferential force on the windings 190 when it is fastened in the cavity 192 of a rotor slot 125 by one or more fastening elements 202. This ensures reliable fixation of the windings 190 within the rotor slot 125 without the need to fill the cavity 192 with potting compound. Furthermore, the use of a clamping wedge 200 enables efficient and complete disassembly of the rotor 120 (thereby increasing the recyclability of the rotor 120).

[0042] A clamping wedge 200 with an elastic wedge body 201 is thus described, which is spread by one or more (radially extending) screws 202 (in particular spread in the circumferential direction), so that the wire windings 190 are pressed by the wedge body 201 against the laminated core, i.e. against the rotor body 122.

[0043] 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

Claims 1) Rotor (120) for an electric machine (100); wherein the rotor (120) comprises, - a rotor body (122) with a first salient pole (124) and a second salient pole (124) by which a rotor slot (125) is bounded; - windings (190) arranged in the rotor slot (125); and - a clamping wedge (200) arranged in the rotor slot (125), which is designed to locally fix the windings (190) within the rotor slot (125). 2) Rotor (120) according to claim 1, wherein - the clamping wedge (200) has a wedge body (201) which is fastened within the rotomut (125) by means of at least one fastening element (202); and - the wedge body (201) touches the windings (190) arranged within the rotor slot (125). 3) Rotor (120) according to claim 2, wherein the wedge body (201) is designed to be elastic such that the wedge body (201) is spread in the circumferential direction when the wedge body (201) is compressed in the radial direction. 4) Rotor (120) according to one of claims 2 to 3, wherein - the rotor body (122) extends in an axial direction from a first end face (128) to an opposite second end face (129); - the Rotomut (125) has a total length from the first end face (128) to the second end face (129); - the wedge body (201) extends in the axial direction from a first position to a second position within the rotor groove (125); - the first position is spaced at most 20% of the total length of the rotor slot (125) from the first end face (128) of the rotor body (122); and - the second position is spaced at most 20% of the total length from the second end face (129) of the rotor body (122). 5) Rotor (120) according to one of claims 2 to 4, wherein - the rotomut (125) extends radially from a base adjacent to a central area (121) of the rotor body (122) to an opening (126) of the rotomut (125) and has a total height; - the wedge body (201) extends radially within the rotor groove (125) from a lower point to an upper point; - the lower point is spaced from the base of the Rotomut (125) by no more than 20% of the total height of the Rotomut (125); and - the upper point is spaced at most 20% of the total height away from the opening of the rotor slot (125). 6) Rotor (120) according to one of claims 2 to 5, wherein the clamping wedge (200) has several fastening elements (202) which are arranged one behind the other, in particular equally distributed, along the axial direction, so that the wedge body (201) is fastened at several points within the rotomut (125). 7) Rotor (120) according to any one of claims 2 to 6, wherein - the rotor body (122) has a central area (121) which adjoins a bottom of the rotor slot (125); - a threaded bore (213) is arranged in the central region (121) of the rotor body (122), which extends radially from the bottom of the rotor groove (125) into the central region (121) of the rotor body (122); and the fastening element (202) comprises a screw which is screwed into the threaded hole (213). 8) Rotor (120) according to one of claims 2 to 7, wherein the fastening element (202) is configured to compress the wedge body (201) in a radial direction. 9) Rotor (120) according to one of the preceding claims, wherein the clamping wedge (200) is configured to exert a circumferential force on the windings (190) so that the windings (190) are pressed against the first salient pole (124) or against the second salient pole (124), and are thereby locally fixed within the rotor groove (125). 10) Rotor (120) according to one of the preceding claims, wherein - the rotor body (122) has N rotor slots (125), with N>4, in each of which windings (190) are arranged; and - the rotor (120) has a clamping wedge (200) in each of the N rotor slots (125) for local fixing of the windings (190) arranged in the N rotor slots (125).

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