Sealing slot wedge for the rotor of an electric machine

Abstract

The invention relates to a slot wedge for covering a rotor slot in a rotor body of a rotor of an electric machine, wherein the rotor slot is delimited by a first salient pole and a second salient pole of the rotor body. The slot wedge comprises a covering region that is designed to cover an opening between the two salient poles of the rotor body. The first salient pole has a first pole shoe having a first limb facing the opening in the rotor slot. The covering region, on the first edge facing the first limb, has a first profile complementary to a corresponding first mating profile of the first limb. The first profile has a covering lip that is designed to cover the first limb from the outside in the region of the first mating profile.

Description

[0001] Sealing groove locking wedge for the rotor of an electric machine

[0002] The invention relates to an electric machine, such as a synchronous machine. In particular, the invention relates to a slot sealing wedge for sealing a rotor slot of a 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 cover 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 slots and / or electrically insulate them from the rotor body. The potting compound is typically applied in liquid form and then cured. During rotor manufacturing, this can lead to liquid potting compound leaking from the cavities, potentially resulting in inadequate winding fixation and / or rotor imbalance. Furthermore, potting compound can accumulate on the rotor's exterior and / or in the air gap, rendering the rotor unusable.This document addresses the technical challenge of enabling a particularly efficient and reliable manufacturing of an electrically excited 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 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 slot closure wedge for covering a rotor slot of a rotor body of an electric machine rotor is described. The rotor slot is bounded by a first salient pole and a second salient pole of the rotor body. Each salient pole can have a pole shoe with legs, the legs extending circumferentially around the rotor body. An opening in the rotor slot is typically formed between the salient poles, particularly between the opposing legs of the pole shoes. This opening can extend along the longitudinal axis of the rotor body from the first end face to the opposite second end face.Furthermore, the opening can extend circumferentially along the surface of the rotor body from the first salient pole (in particular from the first leg of the pole shoe of the first salient pole) to the second salient pole (in particular to the second leg of the pole shoe of the second salient pole). The opening can have the shape of a (missing) segment of the surface of the rotor body.

[0007] The slot closure wedge includes a covering area designed to cover the opening between the two salient poles (in particular the opening between the two legs of the pole shoes of the two salient poles) of the rotor body.

[0008] The cover area can have a first (sectional) profile extending along the longitudinal axis, which is complementary to a corresponding first (sectional) counter-profile of the first leg. Furthermore, the cover area (on the opposite longitudinal side) can have a second (sectional) profile extending along the longitudinal axis, which is complementary to a corresponding second (sectional) counter-profile of the second leg. A profile of the cover area can, for example, have a notch, recess, or groove (along the longitudinal axis) into which a complementary tongue of the respective leg can be arranged as a counter-profile. Alternatively or additionally, a profile of the cover area can have a tongue that can be arranged in a notch, recess, or groove (along the longitudinal axis) of the respective leg as a counter-profile.A notch, depression, or groove can (in relation to the respective cross-sectional profile) be formed as a trough between two wave crests. Conversely, a spring (in relation to the respective cross-sectional profile) can be formed as a wave crest.

[0009] The covering area can have the shape of a segment of the rotor body's outer surface. In particular, the covering area of ​​the slot closure wedge can be designed such that it completes the outer surface of the rotor body at the location of the rotor slot opening when the slot closure wedge covers the opening of the rotor slot.

[0010] The cover area can be arranged above the opening of the rotor slot, so that the slot closure wedge is locally fixed by the opposing legs of the pole shoes, and so that the slot closure wedge is held in the rotor slot by the legs of the pole shoes even when centrifugal forces are present (up to reaching a certain limit centrifugal force).

[0011] As previously explained, the cover area of ​​the groove closure wedge has a first profile on its first longitudinal edge facing the first leg, which is complementary to a corresponding first counter-profile of the first leg. The aspects described in this document regarding the first profile and the first counter-profile are also applicable, mutatis mutandis, to the second profile and the second counter-profile located on the second longitudinal edge of the cover area of ​​the groove closure wedge. Preferably, the first and second profiles are identical. Furthermore, preferably, the first and second counter-profiles are also identical.

[0012] The first profile has a cover lip designed to cover the first leg from the outside in the region of the first mating profile. The first leg may have an outer surface facing away from the rotor groove (which, during operation of the electric machine, faces the stator and / or the air gap between the rotor and the stator, and which, in particular, directly adjoins the air gap between the rotor and the stator). The cover lip may cover the outer surface in the region of the first mating profile (i.e., at the longitudinal edge of the first leg), in particular such that the cover lip forms the outermost point of the rotor in this region (with respect to the radial direction).

[0013] The cover lip may have a seal on the inside facing the first leg (especially on the outside of the first leg) or be designed as a seal.

[0014] The outer surface of the first leg can form part of a wave crest of the first counter-profile. An outer functional surface can be formed between the wave crest of the first counter-profile and the cover lip (where there is contact between the outer surface of the first leg and the cover lip). This outer functional surface is preferably designed as a seal for liquid potting compound.

[0015] By providing a groove closure wedge with a cover lip (in particular, a cover lip on each of the two longitudinal edges of the cover area of ​​the groove closure wedge), a reliable seal against liquid potting compound can be achieved.

[0016] The first profile can have an inner crest (in the radial direction). Furthermore, the cover lip can be designed as the outer crest (in the radial direction) of the first profile, so that a trough (e.g., in the form of a groove) is formed between the inner crest of the first profile and the cover lip to receive a crest (e.g., in the form of a tongue) of the first counter-profile of the first leg. The outer surface of the first leg can be part of the crest of the first counter-profile. The first profile can thus be corrugated along the radial direction. This allows for a particularly reliable seal.An inner functional surface can be formed between the inner wave crest of the first profile and the wave crest of the first counter-profile (where there is contact between the inner wave crest and the wave crest of the first counter-profile), which is designed to absorb centrifugal forces acting in a radial direction on the groove locking wedge.

[0017] This describes a first profile / counter-profile that has several functional surfaces which can be, or have been, optimized for different requirements (force absorption and sealing). This allows the different requirements to be met in a particularly reliable and efficient manner.

[0018] As already explained, the first profile and the first counter-profile can be designed such that a wave-like contact line is formed between the first profile and the first counter-profile in a radial direction (running along the inner wave crest of the first profile, to the wave trough of the first profile up to the cover lip (i.e. the outer wave crest of the first profile).

[0019] A gap can form at a certain point along the contact line between the first leg and the first edge of the cover area of ​​the slot closure wedge. This gap can be formed, for example, by a depression in the trough between the inner crest and the cover lip of the first profile. The gap can have a substantially circular cross-section (perpendicular to the rotor's axis of rotation). Furthermore, the gap can extend over the entire length of the first edge of the cover area of ​​the slot closure wedge.

[0020] The free space can be designed to receive liquid potting compound and thus serve as a buffer for any escaping compound. This reliably prevents the escape of potting compound. The contact line can extend from an inner point facing the Rotomut to an outer point located on the outside of the first leg. The free space is preferably positioned along the contact line closer to the outer point than to the inner point. Alternatively or additionally, the free space can be located between the inner and outer functional surfaces. Such an arrangement of the free space can achieve a particularly reliable seal.

[0021] The slot closure wedge typically includes an immersion area configured such that, when the cover area covers the opening of the rotor slot, the immersion area extends radially from the cover area into the rotor slot (towards the rotor axis). The immersion area may have side walls, each arranged substantially in a plane spanned by the longitudinal axis (i.e., the axis of rotation) and by a radially extending radial axis.

[0022] The immersion zone can extend along the longitudinal axis at least from the first to the second end face of the rotor body. Furthermore, the immersion zone can have a specific immersion depth along the radial direction (starting from the cover area towards the rotor axis of the rotor body).

[0023] The slot locking wedge, in particular the insertion area of ​​the slot locking wedge, can (at least in a region intended to be positioned between the first and second end faces of the rotor body) essentially have the shape of a (right) prism with a specific base. The base can, for example, be triangular or T-shaped. The insertion area of ​​the slot locking wedge can be configured to divide the rotor slot, in or on which the slot locking wedge is positioned, into a first half and a second half along a dividing plane defined by the longitudinal and radial axes, with the first half facing the first salient pole and the second half facing the second salient pole. In the first half of the rotor slot, first windings can be arranged around the first salient pole, and in the second half of the rotor slot, second windings can be arranged around the second salient pole.

[0024] The Rotomut can have a specific total depth in the radial direction with respect to the rotor axis. The immersion zone can have an immersion depth along the radial direction that is 50% or more, in particular 70% or more, of the total depth.

[0025] According to another 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 rotomuth having an opening between the two salient poles. Furthermore, the rotor includes a slot closure wedge (designed as described in this document) that covers the opening. Typically, the rotor includes a plurality of rotomuths (e.g., 4 or more, or 6 or more rotor slots) and a corresponding plurality of slot closure wedges.

[0026] According to another aspect, an electrical machine, in particular a (current-excited) synchronous machine, is described, which includes the rotor described in this document.

[0027] According to another aspect, a (road) motor vehicle (in particular a passenger car, truck, bus, or motorcycle) is described, which includes the electric machine described in this document for propelling the vehicle. It should be noted that the devices, methods, 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.

[0028] The invention will now be described in more detail using exemplary embodiments.

[0029] Figure a is an exemplary electrical machine;

[0030] Figure 1b shows a perspective view of an exemplary rotor body;

[0031] Figure 1c is a perspective view of an exemplary slot locking wedge; Figure Id is a sectional view of a slot locking wedge arranged in a rotor slot; and

[0032] Figures 2a and 2b show different views of a groove locking wedge with a cover lip.

[0033] As stated at the outset, this document deals with the efficient and reliable sealing of the individual rotor slots of the rotor of an electric machine, in particular to enable the efficient and reliable manufacture of an 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. The electric machine 100 comprises a stator 110 with several stator windings 111 arranged at different angular positions around the rotation axis of the rotor 120 and configured to generate a rotating electromagnetic field.The stator 110 is surrounded by a housing 135 of the electric machine 100.

[0034] 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.

[0035] 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.

[0036] 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 of the rotor body 122 via respective bearing surfaces to enable rotation of the rotor 120.

[0037] 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.

[0038] The rotomut 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 extending along the longitudinal axis from the first end face 128 to the second end face 129 of the rotor body 122. In the direction perpendicular 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.

[0039] To manufacture a rotor 120, electrically conductive windings can be wound around the salient poles 124, such that windings of the two directly adjacent salient poles 124 are arranged in each rotor slot 125. After arranging the windings, 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.

[0040] Fig. 1c shows an exemplary slot closure wedge 180, which has a cover area 186 that covers the opening 126 of a rotor slot 125. The cover area 186 can have an outer surface designed to complete the outer surface of the rotor body 122 at the opening 126 to be covered. The cover area 186 can extend (along the longitudinal axis) from a first end face 181 to an opposite second end face 182. The first end face 181 of the cover area 186 can be arranged on the first end face 128 of the rotor body 122. The second end face 182 of the cover area 186 can be arranged on the second end face 129 of the rotor body 122. The length 184 of the cover area 186 of the groove closure wedge 180 can correspond to the total length 127 of the rotor body 122.

[0041] The cover area 186 can have lateral profiles 183, each extending along the longitudinal axis from the first end face 181 to the second end face 182 of the cover area 186. For the insertion of the groove-locking wedge 180 between two legs 131 of the pole shoes 130 of two directly adjacent leg poles 124, a first profile 183 can face a corresponding (complementary) counter-profile 193 of the first leg 131, and the opposite second profile 183 can face a corresponding (complementary) counter-profile 193 of the second leg 131 (see Fig. Id). The counter-profiles 193 of the legs 131 and the corresponding profiles 183 of the groove-locking wedge 180 can be slid into one another, so that the inserted groove-locking wedge 180 is held between the two legs 131. A profile 183 can, for example, have a spring that runs from the first end face 181 to the second end face 182.The complementary mating profile 193 can have a complementary groove for this tongue. Alternatively, the mating profile 193 can have a tongue and the profile 183 can have the complementary groove. As already explained, such a tongue-and-groove connection can be provided by the profiles 183 and 193 having a wave-like cross-section (perpendicular to the longitudinal or rotational axis). The groove-closing wedge 180 can further have an insertion area 185 that extends from the cover area 186 into the rotor groove 125 when the groove-closing wedge 180 covers the opening 126 of the rotor groove 125. The insertion area 185 can extend along the longitudinal axis from the first end face 181 to the second end face 182 of the cover area 186.Furthermore, the immersion area 185 can be extended further along the longitudinal axis at the first end face 181 and / or at the second end face 182 (so that, in the extended state of the slot locking wedge 180, the immersion area 185 projects beyond the first end face 128 and / or the second end face 129 of the rotor body 120). The projecting part of the immersion area 185 can be used, for example, to guide the windings 190 at the respective end face 128, 129 of the rotor body 122 (i.e., at the respective winding head).

[0042] The immersion area 185 can extend radially (i.e., essentially perpendicular to the covering surface of the covering area 186) from the covering area 186 towards the axis of rotation of the rotor body 122. The immersion area 185 can thus penetrate radially into the respective rotor groove 125 when the groove closure wedge 180 covers the rotor groove 125. The immersion area 185 can have a specific immersion depth in the radial direction. The rotor groove 125 can, for example, have a total depth measured from the outer surface of the rotor body 122 (i.e., from the outer diameter of the rotor body 122). The immersion depth of the immersion area 185 can be, for example, 20% or more, or 50% or more, or 70% or more of the total depth.

[0043] As already explained above, in a rotor slot 125, which is bounded by a first salient pole 124 and by a directly adjacent second salient pole 124, first windings 190 around the first salient pole 124 and second windings 190 around the second salient pole 124 can be arranged. The insertion area 185 of the slot closure wedge 180 can be configured to form, at least in part, a partition between the first and second windings 190.

[0044] 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 remaining 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.

[0045] Stop elements 187 can be arranged on the end faces 181, 182 of the cover area 186 of the groove locking wedge 180, with which the groove locking wedge 180 can be fixed along the longitudinal axis (e.g. by abutting a stop element 187 against a bearing or against a slip ring module of the electric machine 100).

[0046] The potting compound is introduced in a liquid state into the cavities 192 of the individual rotor slots 125. Cup-shaped covers with holes can be arranged on the end faces 128, 129 of the rotor body 122, through which the liquid potting compound can be introduced into the cavities 192. The potting compound can be introduced under a specific pressure to ensure that the cavities 192 are completely filled with potting compound.

[0047] When potting compound is introduced, liquid potting compound may escape from the cavity 192 covered by the slot-locking wedge 180 through the gap between the profile 183 of a slot-locking wedge 180 and the mating profile 193 of the pole shoe 130 of a salient pole 124. This can impair the manufacturing process and / or the rotor 120. Figures 2a and 2b show different views of a slot-locking wedge 180 with a covering area 186, which has at least one covering lip 201 that covers a portion of the pole shoe 130 of a salient pole 124 from the outside. As already explained, the profile 183 can be corrugated along a longitudinal edge of the covering area 186 of a slot-locking wedge 180. The profile 183 can have two wave crests 201, 202, which extend circumferentially towards the leg 131 of the pole shoe 130 of a salient pole 124. The outer wave crest corresponds to the cover lip 201.

[0048] A wave trough of profile 183 is formed between the two wave crests 201, 202 of profile 183, in which a wave crest of the counter-profile 193 is arranged, the outwardly oriented side of the wave crest of the counter-profile 193 corresponding to the outer side of the leg 131 of the pole shoe 130 of the limb pole 124. This outer side of the leg 131 of the pole shoe 130 of the limb pole 124 is in contact with the cover lip 201 of the groove locking wedge 180.

[0049] The profile 183 and the counter-profile 193 can be designed such that a free space 203 is formed in the trough of profile 183 between the two crests 201, 202 of profile 183, which is designed to receive potting compound. The free space 203 can serve as a buffer for any potting compound that may escape.

[0050] The profile 183 and the counter-profile 193 can be designed such that the contact line 205 between the two profiles 183, 193 runs in a serpentine or wavy line shape (in the radial direction). In this way, contact between the two profiles 183, 193 can essentially always exist along the contact line 205, except for a region along the contact line 205 where the clearance 203 for receiving potting compound is formed. A first (inner) functional surface 221 is formed between the inner crest 202 of the profile 183 and the crest 211 of the counter-profile 193. This first (inner) functional surface 221 can be used to ensure a particularly stable fixation of the slot locking wedge 180 to the rotor body 122 (even under the influence of centrifugal forces).

[0051] Furthermore, a second (outer) functional surface 222 is formed between the wave crest 211 of the counter-profile 193 and the outer wave crest 202 (i.e., the cover lip) of the profile 183. This second (outer) functional surface 222 can be designed to seal the cavity 192 in the rotor groove 125. For this purpose, a sealing lip and / or a seal can optionally be arranged on the cover lip 202 of the cover area 186 of the groove closure wedge 180. The sealing effect of the profiles 183, 193 is further achieved by the labyrinthine and / or serpentine contact line 205 of the profiles 183, 193.

[0052] 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) Slot closure wedge (180) for covering a rotor slot (125) of a rotor body (122) of a rotor (120) of an electric machine (100), wherein the rotor slot (125) is bounded by a first salient pole (124) and a second salient pole (124) of the rotor body (122); wherein - the slot closure wedge (180) comprises a cover area (186) designed to cover an opening (126) between the two leg poles (124) of the rotor body (122); - the first salient pole (124) has a first pole shoe (130) with a first leg (131) facing the opening (126) of the rotor slot (125); - the covering area (186) has a first profile (183) on a first edge facing the first leg (131), which is complementary to a corresponding first counter-profile (193) of the first leg (131); and - the first profile (183) has a cover lip (202) which is designed to cover the first leg (131) in the area of ​​the first counter-profile (193) from the outside. 2) Groove locking wedge (180) according to claim 1, wherein the cover lip (202) has a seal or is designed as a seal on an inner side facing the first leg (131). 3) Groove locking wedge (180) according to one of the preceding claims, wherein - the first profile (183) has an inner wave crest (202); - the cover lip (202) is designed as the outer wave crest of the first profile (183), so that between the inner wave crest (202) of the first profile (183) and the cover lip (202) there is a wave trough to receive a wave crest (211) of the first counter-profile (193) of the first Schenkels (131) is formed. 4) Groove locking wedge (180) according to claim 3, wherein - an inner functional surface (221) is formed between the inner wave crest (202) of the first profile (183) and the wave crest (211) of the first counter-profile (193) to absorb centrifugal forces acting in a radial direction on the groove locking wedge (180); and - an outer functional surface (222) between the wave crest (211) of the first counter-profile (193) and the cover lip (201) is designed as a seal for liquid potting compound. 5) Groove locking wedge (180) according to one of the preceding claims, wherein the first profile (183) and the first counter-profile (193) are designed such that - a wavy contact line (205) is formed in the radial direction between the first profile (183) and the first counter-profile (193); and - at one point along the contact line (205) a free space (203) is formed between the first leg (131) and the first edge of the cover area (186) of the groove closure wedge (180). 6) Groove locking wedge (180) according to claim 5, wherein - the contact line (205) runs from one of the inner points facing the rotomut (125) to an outer point located on an outer side of the first leg (131); and - the free space (203) is located at a point along the contact line (205) that is closer to the outer point than to the inner point. 7) Groove locking wedge (180) according to one of claims 5 to 6 with reference to claim 4, wherein the clearance (203) between the inner is arranged between the functional surface (221) and the outer functional surface (222). 8) Groove locking wedge (180) according to one of claims 5 to 7 with reference to claim 3, wherein the clearance (203) is formed by a dent in the wave valley between the inner wave crest (202) and the cover lip (201) of the first profile (183). 9) Groove locking wedge (180) according to one of the claims, wherein the groove locking wedge (180) comprises an immersion area (185) which is designed such that the immersion area (185) extends from the cover area (186) into the rotomut (125) when the cover area (186) covers the opening (126) of the rotomut (125). 10) 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, which has an opening (126) between the two salient poles (124); and - a groove closure wedge (180) according to one of the preceding claims, by which the opening (126) is covered.

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