Stator for an electric machine

Abstract

Stator (1) for an electric machine, comprising a stator core (2) with slots (5) and a hairpin winding (3) defining at least three phase windings (U, V, W). Each phase winding has a plurality of parallel branches, each branch of each phase winding having a phase contact (Un, Vn, Wn) and a neutral contact (NUn, NVn, NWn), all of which are arranged at the connection end (10) in an outermost layer (Lz) or an innermost layer (L1), wherein at least one pair of the phase contacts of at least one phase winding both extend from a common phase contact slot (51), wherein a first half of the phase connections of at least one phase winding extends in the outer layer (LZ) from at least one first offset phase contact slot (52), and wherein a second half of the phase connections extends in the inner layer (L1) from at least one second offset phase contact slot (53).wherein the first offset phase contact groove (52) is offset circumferentially relative to the second offset phase contact groove (53), wherein at least one pair of the neutral contacts of the parallel branches both extend from a common neutral contact groove (56), wherein a first half of the neutral contacts of at least one phase winding in the innermost layer (L1) extends from at least one first offset neutral contact groove (57), wherein a second half of the neutral contacts in the outermost layer (LZ) extends from at least one second offset neutral contact groove (58), wherein the first offset neutral contact groove (57) is offset circumferentially relative to the second offset neutral contact groove (58).

Description

[0001] The present application relates to a stator for an electrical machine having a stator core with a plurality of slots and with a hairpin winding.

[0002] With the increasing power requirements of electrical machines, windings made of hairpin conductors with rectangular wire cross-sections were introduced, offering a higher slot fill rate and power density. The structure of the stator winding and the winding connections of the phase leads and neutral contact are distributed to minimize the number of specially shaped hairpin conductors for ease of manufacturing.

[0003] CN 213782983 U relates to a flat-wire hairpin stator structure and a motor. The flat-wire hairpin stator structure includes a stator core, a stator winding, and a bus bar. The stator iron core includes an iron core body and a plurality of stator slots formed at regular intervals in the circumferential wall surface of the inner side of the iron core body and extending in the axial direction of the iron core body. The stator winding includes a plurality of layers of flat wire conductors inserted into each stator slot, one end of each layer of flat wire conductors being an insertion end and the other end of each layer of flat wire conductors being a connection end. The multiple layers of flat wire conductors are bent in the circumferential direction of the iron core body to form a U-phase winding, a V-phase winding, and a W-phase winding in a surrounding mode.An output conductor and a neutral conductor of each parallel branch of each phase winding are arranged at the connecting ends of the flat wire conductors. The busbar includes a U-phase output busbar, a V-phase output busbar, a W-phase output busbar, and a neutral busbar, which are arranged at the connecting end of the flat wire conductor. The layout of the multi-layer flat wire conductor of the stator winding is simplified, and the overall size of the flat wire hairpin motor is reduced.

[0004] CN 113809857 A discloses a multilayer hairpin flat-wire winding stator comprising a stator core and a hairpin flat-wire wave winding. Stator slots are arranged in the stator core, and the hairpin flat-wire wave winding is embedded in the stator slots. The hairpin flat-wire wave winding comprises more than two branches. The stator slots, in which the three-phase windings of the hairpin flat-wire wave winding are located, are spaced in pairs and arranged consecutively. Any branch switches to an equivalent slot of the adjacent stator slot after circumferentially circling half of the layers, and a long-distance or short-distance connection is assumed when the branch switches to the equivalent slot of the adjacent stator slot in a cross-layer mode such that the head end and the tail end of any branch are located on the innermost layer and the outermost layer in the radial direction of the stator.A long-distance or short-distance connection only occurs where there is a cross-layer transposition to equivalent slots of adjacent stator slots, so that the head and tail ends of the branches are located on the innermost layer and the outermost layer in the radial direction of an armature and a single branch of each phase can be passed through equivalent positions of all layers of all stator slots of the phase in which the single branch is located.

[0005] CN 114172294 A discloses a flat wire motor and a wire outlet mechanism and a corresponding winding mechanism, and the wire outlet mechanism includes a neutral rail comprising an arcuate plate arranged perpendicular to the axis of the winding of the flat wire motor and embedded in the end surface of the winding; the binding pins are arranged on the inner curved surface and the outer curved surface of the arcuate plate and are used to be connected to the winding, and the binding pins arranged on the inner curved surface and the outer curved surface are arranged in a staggered manner; the wiring terminal includes a wiring main board arranged perpendicular to the plane in which the arcuate plate is located;The input line is located in the center of the wiring main board, far from one side of the arc-shaped plate, and is used to access the external wiring voltage; and the outgoing lines are located at both ends of the wiring main board and are used to connect to the winding. The flat wire motor, wire outlet mechanism, and winding mechanism can reduce the design cost of the flat wire motor.

[0006] CN 215300307 U discloses a flat wire winding structure and a stator and a motor comprising the same, wherein the flat wire winding structure is arranged in a stator core, and a tooth portion of the stator core is provided with a plurality of wire slots. Each wire slot is provided with an even number of mounting positions arranged in a radial direction and serving to receive pins of a plurality of flat wire coil conductors. The flat wire winding structure includes a first phase winding, a second phase winding, and a third phase winding, and each phase winding includes four parallel branches.Each of the first phase winding, the second phase winding, and the third phase winding has a double-layer winding structure. In a circuit of winding around the stator core, each parallel branch is inserted from the upper layer of one wire slot and exited from the lower layer of the other wire slot. The two different parallel branches of the same phase winding in the wire slots overlap to form the double-layer winding structure. The motor according to the utility model has better torque performance and a higher power factor.

[0007] DE 10 2017 201 533 A1 discloses a stator for an electrical machine comprising an annular laminated core having a longitudinal axis and a plurality of slots each extending along the longitudinal axis, at least three electrical phases U, V, W, each having two partial strands, a plurality of rings which, when connected in series, each form a partial strand, a plurality of connecting wires which are each arranged to form a ring in adjacent layers of the slots, a power connection for electrically connecting the stator, wherein the connecting wires are each connected in pairs on a contacting side of the laminated core for connecting adjacent layers at contacting regions, the power connection is arranged on the contacting side and the connecting wires are each closed on a counter-contacting side opposite the contacting side.

[0008] DE 10 2018 207 224 A1 discloses a stator for an electrical machine, wherein the stator comprises a plurality of hairpin conductors, wherein the hairpin conductors are connected to one another in such a way that three stator windings are formed, wherein the stator comprises current transmission elements for transmitting current, wherein each current transmission element is assigned a stator winding. The stator comprises a connecting element for connecting the stator windings to form a circuit and insulation elements, wherein the connecting element is insulated on both sides in the axial direction of the stator by at least one insulation element, wherein at least one first insulation element is formed at a first axial end of the connecting element for insulation from the current transmission elements, and wherein at least one second insulation element is formed at a second axial end of the connecting element for insulation from end regions of hairpin conductors.

[0009] DE 10 2019 105 563 A1 discloses a stator for an electric motor, comprising a plurality of pins arranged on at least two concentric circles; an interface having at least one contact surface connected to two electrically conductive legs and supported by the legs, wherein the legs are connected to at least one pin on different concentric circles.

[0010] DE 10 2021 100 731 A1 discloses a high-voltage terminal for a stator, comprising three busbars for electrically connecting the HV terminal to power electronics and a star busbar, wherein each of the three busbars has a current input element and at least n parallel current output elements and the star busbar has at least 4 current input elements, and wherein the busbars are stacked one above the other within the HV terminal to form a busbar stack and are arranged so as to be electrically insulated from one another via at least one plastic element, in particular are electrically insulated from one another, preferably embedded, in a plastic element.

[0011] CN 113675965 A discloses a motor stator comprising a stator winding, each phase winding comprising at least one conductor group, each conductor group comprising a long layer crossing conductor radially crossing a G layer in two slots, G / 2 immediately adjacent layer crossing conductors in the same radial layer crossing direction as the long layer crossing conductors and G / 2-1 inverse adjacent layer crossing conductors in the opposite radial layer crossing direction as the long layer crossing conductors are arranged between the radial cross layers of the long layer crossing conductors, and G is greater than or equal to 4 and less than or equal to M; and the inner sides of the two slots of the remaining conductors except for the long layer crossing conductor in each phase winding are arranged on two adjacent layers in the circumferential direction of a stator core.This eliminates gap bridge conduction, heat dissipation is uniform, power and torque are improved, wiring mode is simplified, process is simplified, and machining efficiency is improved.

[0012] One object is to provide a stator for an electrical machine having a stator core having a plurality of slots and a hairpin winding, wherein the hairpin winding has a scalable layout to improve the manufacture of a wide range of electrical machines.

[0013] The object is achieved by a stator for an electrical machine according to claim 1. Advantageous embodiments are the subject of the dependent claims.

[0014] The stator for an electrical machine comprises a stator core with a plurality of slots and a hairpin winding. The hairpin winding comprises hairpin conductors with two leg sections connected at a head section, wherein a slot spacing between the two leg sections is defined by the head section, wherein the slot spacing of each of the hairpin conductors is identical. The leg sections of the hairpin conductors are received in the slots in at least two radially adjacent layers, wherein the head sections protrude from the stator core at an insertion end and end sections of the leg sections opposite the head sections protrude from the stator core at a connection end.The hairpin winding defines at least three phase windings, each phase winding having at least one branch, each branch of each phase winding having a phase contact formed at one of the end portions for connection to a phase busbar and a neutral contact formed at one of the end portions for connection to a neutral busbar. The phase contacts and the neutral contacts are all arranged at the connecting end of the hairpin winding in at least one of an outermost layer of the radially adjacent layers and an innermost layer of the radially adjacent layers.

[0015] One advantage of the stator is that the hairpin winding structure is scalable to electrical machines with different parameters regarding the number of layers per slot, the number of slots, the number of turns of the phase winding, the number of slots per pole and per phase, the number of parallel branches per phase, the number of poles, and the number of phases. The fact that the slot spacing of the individual hairpin conductors is identical means that all hairpin conductors span the same number of slots in the circumferential direction of the slots and the same number of layers in the radial direction. The actual spacing between the two leg sections depends on the spacing of the respective slots and layers, which increases in the radial direction.The arrangement of the phase contacts and the neutral contact at the connecting end of the hairpin winding facilitates the manufacturing process, since the welding work to create the contacts with the respective busbars is carried out in a limited area.

[0016] The hairpin conductors can be made of wire with a rectangular cross-section, e.g., flat wire. The wire of the hairpin conductors is usually solid, but can also be hollow, for example, to create a cooling channel through the hairpin conductor. The leg sections and the head sections can be formed by bending the wire. The leg sections are received in different slots of the stator core and in different layers, with the slot spacing of the head section spanning the circumferential distance between the two slots and the radial distance between the two layers. The stator core has a generally cylindrical shape that defines a longitudinal axis, with reference to which all specifications regarding circumferential, axial, and radial directions are to be understood.The end sections along each branch are electrically connected together, usually by welding, with each branch forming a conductor with one of the phase contacts at one end and one of the neutral contacts at the other. The connected end sections of two consecutive hairpin conductors of a branch have the same slot spacing as the head sections. The neutral contacts may be connected to a single neutral busbar, forming a star connection, or the neutral contacts of each pair of phase windings may be connected to one of several neutral busbars, forming a delta connection. The connection of the phase contacts and the neutral contacts is advantageously facilitated by arranging the phase contacts and the neutral contacts all at the connecting end of the hairpin winding.In addition, the phase busbars and neutral busbars can be arranged radially between the phase contacts and the neutral contacts in the outermost layer and the innermost layer, thereby reducing the overall axial length of the stator. A group of end sections forming the phase contacts and the neutral contacts can extend axially beyond a group of end sections forming the electrical connections, which can be welded together in pairs to form the parallel branches of the phase windings. The neutral contact of each branch is arranged in the layer radially opposite the respective phase contact of the branch. Each branch therefore extends, starting from the phase contact, from either the innermost or the outermost layer to the radially opposite layer.The branches emanating from the innermost layer are wound around the stator in the opposite direction of rotation than the branches emanating from the outermost layer.

[0017] According to one embodiment, a contact area is defined as a sector of a stator circumference occupied by the phase contacts and the neutral contacts at the connection end, wherein a span of the contact area over a circumference of the stator is minimized. The span of the contact area over a circumference of the stator is minimized. This means that the phase contacts and the neutral contacts are located as close to each other as possible to reduce the contact area of ​​the contacts to a minimum. The resulting minimized span depends on the number of poles and the number of slots per pole and phase of the stator.

[0018] In a further embodiment, the phase contacts are evenly distributed between the outermost layer and the innermost layer. For example, a first half of the phase contacts are arranged in the outermost layer and a second half of the phase contacts in the innermost layer. The distribution of the phase contacts between the outermost and innermost layers has the advantage that the phase contacts are bundled over a limited area of ​​the circumference, thereby reducing the circumferential expansion of the welding processes. In general, the number of branches per phase winding can be any natural number greater than zero. Those skilled in the art will be aware that with an odd number, the phase contacts cannot be evenly distributed.Nevertheless, a distribution of one phase contact in the outermost position and two phase contacts in the innermost position or two phase contacts in the outermost position and three phase contacts in the innermost position is advantageous, since the corresponding neutral contacts are always arranged in the opposite position of the phase contacts.

[0019] According to the invention, each phase winding has a plurality of parallel branches, with at least one pair of phase contacts of the parallel branches of at least one phase winding both extending from a common phase contact slot. Thus, if a phase winding has two parallel branches, one phase contact is arranged in the outermost position of this common phase contact slot and the other phase contact is arranged in the innermost position of this common phase contact slot.

[0020] According to a further embodiment, several pairs of phase contacts of the parallel branches of the at least one phase winding extend in pairs from several adjacently arranged common phase contact slots. If a phase winding has, for example, four or six branches, two or three phase contacts can be arranged in the outermost layer, and the two or three other phase contacts can be arranged in pairs in two or three common phase contact slots, which can be arranged adjacently.

[0021] According to the invention, each phase winding has a plurality of parallel branches, wherein a first half of the phase contacts of the parallel branches of at least one phase winding extends from the innermost layer of at least one first offset phase contact slot, and wherein a second half of the phase contacts of the at least one phase winding extends from the outermost layer of at least one second offset phase contact slot, and wherein the at least one first offset phase contact slot is offset in the circumferential direction relative to the at least one second offset phase contact slot. This is particularly advantageous for hairpin windings with an odd number of phase windings.If the parallel branches of at least one phase winding are combined in pairs in common phase contact slots and the parallel branches of at least one other phase winding are distributed circumferentially into offset phase contact slots, this results in a closer overlap of the associated neutral contacts with the phase contacts over a limited span of the circumference, which in turn reduces the circumferential extent of the welding processes.

[0022] Furthermore, according to the invention, each phase winding has a plurality of parallel branches, wherein at least one pair of neutral contacts of the parallel branches of at least one of the phase windings both extend from a common neutral contact slot. If, for example, a phase winding has two parallel branches, one neutral contact is arranged in the outermost position of this common neutral contact slot and the other neutral contact is arranged in the innermost position of this common neutral contact slot. If the phase winding further has more than two parallel branches, several pairs of neutral contacts of the parallel branches of the at least one phase winding extend in pairs from several adjacently arranged common neutral contact slots.

[0023] Furthermore, according to the invention, each phase winding has a plurality of parallel branches, wherein a first half of the neutral contacts of the parallel branches of at least one phase winding extends from the innermost layer of at least one first offset neutral contact slot, and wherein a second half of the neutral contacts of the at least one phase winding extends from the outermost layer of at least one second offset neutral contact slot, and wherein the at least one first offset neutral contact slot is offset in the circumferential direction relative to the at least one second offset neutral contact slot. Offsetting the neutral contacts of a phase winding in the circumferential direction into the first and second offset neutral contact slots has the advantage that one of the first and second offset neutral contact slots can be arranged between two of the common phase contact slots, which leads to a closer overlap of the slots occupied by phase and neutral contacts.The person skilled in the art will be aware that either half of the neutral contacts or half of the phase contacts of a phase winding are offset, which in both cases leads to the same advantageous result.

[0024] The slots occupied by phase contacts and neutral contacts are the common phase contact slots, the first offset phase contact slots, the second offset phase contact slots, the common neutral contact slots, the first offset neutral contact slots, and the second offset neutral contact slots, which together define a contact slot region that extends circumferentially over a fraction of the total number of slots. The contact slot region may extend over less than two-thirds of the total number of slots, preferably over less than half of the total number of slots. The contact slot region may extend over a contiguous region of adjacent slots in which at least one of the phase contacts or at least one of the neutral contacts is arranged.

[0025] According to an embodiment not claimed, each phase winding has several parallel branches, wherein at least the phase contact of a first branch and the neutral contact of a second branch are arranged in one of the outermost layer and the innermost layer, wherein the first branch and the second branch are connected to each other on the respective opposite layers of the outermost layer and the innermost layer. This embodiment reduces the number of phase and neutral contacts by connecting two branches and makes it possible to arrange the neutral contact of the first branch and the phase contact of the second branch in the same layer. The connection between the phase contact of the first branch and the neutral contact of the second branch can be established by a bridge. The branches of each phase winding can be connected in pairs in this way.

[0026] Exemplary embodiments and further features and advantages are explained with reference to the drawings. It shows Fig. 1A and Fig. 1B embodiments of a stator for an electrical machine in cross section; Fig. 2A and Fig. 2B enlarged details of the stators of the Fig. 1A and Fig. 1B; Fig. 3 a hairpin ladder; Fig. 4 shows a perspective view of a non-claimed embodiment of the stator; Fig. 5 an enlarged section of Fig. 4; Fig. 6 is a general diagram of a winding structure of a non-claimed embodiment of the stator; Fig. 7 is a general schematic representation of a winding structure according to another embodiment of the stator not claimed; Fig. 8 is a general schematic representation of a winding structure of an embodiment of the stator according to the invention; Fig. 9 a perspective view of a stator according to the invention for an electrical machine; Fig. 10 an enlarged section of Fig. 9; Fig. 11 an enlarged section of Fig. 9 with busbars in an exploded view; Fig. 12 the detail from Fig. 11 in perspective view; Fig. 13 is an exemplary schematic diagram of a winding structure for the stator according to the embodiment of the invention.

[0027] In Fig. 1A shows an embodiment of a stator 1 for an electrical machine in a schematic cross-sectional view in the direction of a longitudinal axis A. A stator core 2 has a plurality of slots 5 in which a hairpin winding (see Fig. 4). In the illustrated embodiment, the stator core 2 has 48 slots 5, which are evenly distributed in the circumferential direction of the stator core 2. Leg sections of hairpin conductors (see Fig. 3) are accommodated in the slots 5 in at least two radially adjacent layers Li, where i is an index indicating the number Z of layers Li. The stator 1 in Fig. 1A has eight layers of Li.

[0028] In Fig. 1B shows a further embodiment of the stator 1 in a schematic cross-section in the direction of the longitudinal axis A. The stator core 2 also has 48 slots 5 evenly distributed in the circumferential direction of the stator core 2, each slot 5 having four layers Li in this embodiment.

[0029] In Fig. 2A is an enlarged detail of one of the grooves 5 of Fig. 1A. In the illustrated embodiment, the leg portions 6 are received in the groove 5 in each of the eight radially adjacent layers Li, where L1 denotes the innermost layer and L8 the outermost layer. More generally, the outermost layer is designated Lz for any number of z layers Li.

[0030] In Fig. Figure 2B is an enlarged detail of one of the grooves 5 of Fig. 1B. In this embodiment, the leg sections 6 are arranged in four radially adjacent layers Li, where L1 is the innermost layer and L4 is the outermost layer Lz.

[0031] In Fig. 3 shows a detail of a hairpin conductor 4. The hairpin winding (see Fig. 4) consists of several hairpin conductors 4 with two leg sections 6 that are connected at a head section 7, with a slot spacing being defined by the number of slots 5 spanned by the head section 7. The slot spacing of the individual hairpin conductors 4 of the hairpin winding is identical. The two leg sections 6 of the hairpin conductor 4 are received in two different slots 5 and in two different layers Li. The hairpin conductor 4 is shown in the shape it has when installed in the stator 1. Before assembly, the end sections 8 are still straight and form a line with the leg sections 6. The end sections 8 are only offset after the hairpin winding has been inserted into the slots 5.

[0032] In Fig. 4 is the stator 1 from Fig. 1 according to a non-claimed embodiment in a perspective view. The head sections 7 of the hairpin conductors 4 protrude from the stator core 2 at an insertion end 9. The part of the hairpin winding 3 that extends from the insertion end 9 is also referred to as the crown side. The end sections 8 of the leg sections 6 opposite the head sections 7 protrude from the stator core 2 at a connecting end 10. The hairpin winding 3 is mounted outside the stator 1 and then inserted into the slots 5 from the insertion end 9. The end sections 8 of the leg sections 6 are straight until after insertion into the stator core 2 and are then set into the shape shown, wherein the end sections 8 of the leg sections 6 are set in a slot 5 alternately from layer to layer clockwise and counterclockwise. Hairpin winding 3 defines three phase windings for the three phases U, V and W.Each phase winding has four parallel branches, starting at a phase contact Un, Vn, Wn and ending at a neutral contact NUn, NVn, NWn. In the designation of the phase contacts and the neutral contacts, "U, V and W" denote the phases and "n" is a subscript that identifies the respective branch, ie 1 to 4 in this design. The phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn are shown in . Fig. 5 fully designated and with reference to Fig. 5. All phase contacts Un, Vn, Wn and neutral contacts NUn, NVn, NWn are arranged on the connection side 10. The hairpin conductors 4 forming a branch are electrically connected to one another at the end sections 8 by spot welding. The end sections 8 forming the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn extend axially beyond the end sections 8 forming the spot-welded electrical connections 16. The four phase contacts Un of the parallel branches of the U-phase winding are connected to a corresponding U-phase busbar 12, the phase contacts Vn of the V-phase winding are connected to a V-phase busbar 14, and the phase contacts Wn of the W-phase winding are connected to a corresponding W-phase busbar 15. The neutral contacts NUn, NVn, NWn are all connected to a neutral contact busbar 11, which in this embodiment forms a star connection.A contact area 17 is defined as a sector of the circumference of the stator 1 occupied by the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn on the connection side 10. The contact area 17 extends over less than half the circumference of the stator 1, in this embodiment over one-third of the circumference of the stator 1.

[0033] In Fig. 5 is the connection end 10 of Fig. 4 as an enlarged detail without the busbars. The arrangement of the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn is shown in Fig. 5. The hairpin winding 3, which defines the three phase windings, has four parallel branches per phase U, V, W. The phase contacts are designated U1, U2, U3, U4, V1, V2, V3, V4, W1, W2, W3, W4 and the neutral contacts are designated NU1, NU2, NU3, NU4, NV1, NV2, NV3, NV4, NW1, NW2, NW3, NW4. The phase contacts designated U1, U2, V1, V2, W1, W2 and the neutral contacts designated NU3, NU4, NV3, NV4, NW3, NW4 are arranged in the outermost layer L8 of the radially adjacent layers Li, and the phase contacts designated U3, U4, V3, V4, W3, W4 and the neutral contacts designated NU1, NU2, NV1, NV2, NW1, NW2 are arranged in the innermost layer L1 of the radially adjacent layers Li. In the illustrated embodiment, the phase contacts Un, Vn, Wn are evenly distributed between the outermost layer Lz and the innermost layer L1.The phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn are arranged in a compact manner in a sector of the circumference of the stator 1, the contact area 17. The radially extending rows of end sections 8 generally correspond to the 48 slots of the stator 1, whereby it should be noted that the end sections 8 are all offset by the same radial distance clockwise or counterclockwise. In this embodiment, the contact area 17 thus extends over 16 of the 48 slots 5 or over a circular sector of 120° of the stator 1. The contact area 17 comprises four slots 5 or rows of end sections 8 with the shorter spot-welded electrical connections 16, which are enclosed by the longer phase contacts Un, Vn, Wn and neutral contacts NUn, NVn, NWn. All welding work on the connections of the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn on the busbars 11, 12, 14, 15 is limited to one third of the stator circumference.

[0034] In Fig. Figure 6 shows a generalized diagram of a winding structure for a stator according to a non-claimed embodiment with discrete parameters for the U, V, and W phases. The upper matrices of each phase illustrate an exemplary branch of the respective phase winding with the phase contacts Uk, Vk, Wk of the respective parallel branches numbered k in the outermost layer Lz and with the neutral contacts NUk, NVk, NWk of said parallel branches numbered k in the innermost layer L1, where k is an integer between 1 and N / 2, where N is the total number of parallel branches per phase winding.The lower matrices of each phase U, V, W illustrate another exemplary branch of the respective phase winding with the phase contacts Ul, VI, Wl of the parallel branches number I in the innermost layer L1 and the neutral contacts NUI, NVI, NWI of said parallel branches number I in the outermost layer Lz, where I is an integer between N / 2+1 and N. The matrices represent the slots 5 in columns and the layers Li in rows for any number of slots 5 and layers Li to illustrate that the proposed concept is modular and can be applied to stator cores with any parameters, provided the parameters meet the conditions described below, where z is the number of layers and Qs is the number of stator slots 5. .

[0035] The layers are denoted by Li, where i is an index from the innermost layer L1 to the outermost layer Lz. Accordingly, the matrix number i denotes the rows, where i is an integer from 1 to z, i=[1, z]. The slots are denoted by Sj, where j is an index from S1 to SQs. Accordingly, the matrix number j denotes the columns, where j is an integer from 1 to Qs, j=[1, Qs]. The number of phase contacts in the outermost layer Lz is k, with k=[1, N / 2]. The number of phase contacts in the innermost layer L1 is I, with I=[N / 2+1, N]. The number z of layers per slot is at least two, 2 ≤ z, where z is an even integer. The number p of pole pairs is at least one, 1 ≤ p, where p is an integer. The number q of slots per pole and per phase is at least one, 1≤ q, where q is an integer.The number N of parallel branches per phase winding is between two and twice the number of slots per pole and per phase, 2 ≤ N ≤ 2q, where N is a positive divisor of 2q. The number Nph of turns of the phase winding is calculated as Nph = (p*q*Z) / N. The number m of phase windings is at least three, m ≥ 3, where m is an integer. The number Qs of stator slots is given by the rule Qs=2p*m*q.

[0036] The U-phase branch of the upper matrix begins at the phase contact Uk in the slot S1 in the outermost layer Lz. The hairpin conductors 4 are represented by arrows pointing to the slot and the layer to which they extend. The dashed lines of the arrows illustrate that any number of slots and layers is spanned by the required number of hairpin windings 4. The branch ends at the neutral contact NUk in the slot SQ-(2*q) in the innermost layer L1. The U-phase branch of the lower matrix begins at the phase contact UI in the slot S1 in the innermost layer L1. The winding direction of the hairpin conductors 4 has the opposite direction of rotation to that of the branch of the upper matrix. The branch ends at the neutral terminal NUI in the slot S1+(3*q) in the outermost layer Lz. If the two in Fig. 6 are installed in one stator core, the slot S1 is one of the common phase contact slots 51, the slot SQ-(2*q) is the first offset neutral contact slot 57, and the slot S1+(3*q) is the second offset neutral contact slot 58.

[0037] The V-phase branch of the upper matrix starts at the phase contact Vk in the slot S1+(2*q) in the outermost layer Lz. The branch ends at the neutral contact NVk in the slot SQ in the innermost layer L1. The V-phase branch of the lower matrix starts at the phase contact VI in the slot S1+(2*q) in the innermost layer L1. The branch ends at the neutral contact NVI in the slot S1+(5*q) in the outermost layer Lz. When the two branches of the V-phase are installed in one stator core, the slot S1+(2*q) is one of the common phase contact slots 51, the slot SQ is the first offset neutral contact slot 57, and the slot S1+(5*q) is the second offset neutral contact slot 58.

[0038] The W-phase branch of the upper matrix starts at the phase contact Wk im in the slot S1+(4*q) in the outermost layer Lz. The branch ends at the neutral contact NWk in the slot S1+q in the innermost layer L1. The W-phase branch of the lower matrix starts at the phase contact WI im in the slot S1+(4*q) in the innermost layer L1. The branch ends at the neutral contact NWI in the slot SQ-(4*q) in the outermost layer Lz. When the two branches of the W-phase are installed in one stator core, the slot S1+(4*q) is one of the common phase contact slots 51, the slot S1+q is the first offset neutral contact slot 57, and the slot SQ-(4*q) is the second offset neutral contact slot 58.

[0039] The contact slot area 18 of the winding structure extends from slot SQ-(4q) through slot S1 to slot S1+(4*q). No phase and neutral contacts protrude from slots SQ-q and SQ-(3*q), so that the shorter spot-welded electrical connections 16 are enclosed by the longer phase and neutral contacts in the contact area 17 ( Fig. 4). Applying the generalized winding scheme to the embodiment of the Fig. 4 and Fig. 5, the windings are shown starting at the phase contacts U1, V1, W1 and U3, V3, W3, with the stator core 2 having the following parameters: z = 8 layers per groove, p = 4 pole pairs, q = 2 slots per pole and per phase, N = 4 parallel branches, Nph = 32 phase winding turns connected in series, k = 3 phases, Qs = 48 grooves.

[0040] In Fig. Figure 7 is a general schematic diagram of a winding structure according to a non-claimed embodiment for the U-phase only. Fig. 6 statements regarding the designations and conditions also apply to Fig. 7. However, the embodiment is intended for stators with a number of parallel branches N that is less than twice the number of slots per pole and per phase, N<2q. The branch begins at the phase contact Uk in the slot S1 in the outermost layer Lz and completes the turn in the innermost layer L1 in the slot SQ-(2*q), but does not end there. Instead, the end section 8 protruding from the slot SQ-(2*q) is connected to a first end of a bridge 19, which is connected at its second end to the end section 8 protruding from the slot S1 in the innermost layer L1. From there, the branch changes the direction of rotation of the winding direction of the hairpin conductors 4 and ends at the neutral terminal NUk in the slot S1+(3*q) in the outermost layer Lz. In this embodiment, all phase contacts Un of the branches per phase can only be inserted through the outermost layer Lz, and the corresponding neutral contacts NUn exit in the same layer, the outermost layer Lz.In the innermost layer L1, a configuration of bridges 19 enables parallel connections that redistribute the outputs of the branches to the input layer. Those skilled in the art will recognize that the phase contacts Un and the corresponding neutral contacts NUn can alternatively be arranged in the innermost layer L1, with the connections being realized by the bridges 19 in the outermost layer Lz.

[0041] In Fig. 8 shows a generalized diagram of a winding structure according to the invention, wherein a span of the contact area 17 ( Fig. 9) is minimized over a circumference of the stator 1. The Fig. 6 statements regarding the designations and conditions also apply to Fig. 8. The U and V phases are identical to the design in Fig. 6 and are not shown again. The embodiment differs only with respect to the W phase, although the difference can apply to any of the phases.

[0042] The W-phase winding has several parallel branches, two of which are shown, one in the upper matrix and one in the lower matrix. In the upper matrix, the phase contact Wk extends from the slot S+(4*q) in the outermost layer Lz, and the neutral contact NWk extends from the slot S1+q in the innermost layer L1. In the lower matrix, the phase contact WI extends from the slot SQ-q in the innermost layer L1, and the neutral contact NWI extends from the slot S1+q in the outermost layer Lz. The phase contact Wk extends from a first offset phase contact slot 52 and the phase contact WI from a second offset phase contact slot 53. The first offset phase contact slot 52 is circumferentially offset from the at least one second offset phase contact slot 53. However, the two neutral contacts NWk, NWI both originate from a common neutral contact slot 56.By offsetting half of the phase contacts of at least one phase, the resulting structure does not enclose any of the shorter spot-welded electrical connections 16 between the longer phase contacts and neutral contacts within the contact area 17, as shown in . Fig. 9 can be seen.

[0043] In Fig. Figure 9 shows a perspective view of another embodiment of a stator 1 for an electrical machine. The end sections 8 projecting from the stator core 2 at the connecting end 10 are straight until they are inserted into the stator core 2 and are then twisted into the shape shown, with the end sections 8 being twisted alternately clockwise and counterclockwise from layer to layer. The hairpin winding 3 defines three phase windings for the three phases U, V, and W. Each phase winding has four parallel branches, each starting at a phase contact Un, Vn, Wn and ending at a neutral contact NUn, NVn, NWn, which will be described in detail with reference to Fig. 10 is described.

[0044] In Fig. 10 is an enlarged section of Fig. 9. The Fig. 9 and Fig. 10 are described together. All phase contacts Un, Vn, Wn and neutral contacts NUn, NVn, NWn are arranged on the connection side 10. The hairpin conductors 4 forming a branch are electrically connected to each other at the end portions 8 by spot welding. The end portions 8 forming the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn extend axially beyond the end portions 8 forming the spot-welded electrical connections 16. The four phase contacts Un of the parallel branches of the U-phase winding are connected to a corresponding U-phase busbar 12, the phase contacts Vn of the V-phase winding are connected to a V-phase busbar 14, and the phase contacts Wn of the W-phase winding are connected to a corresponding W-phase busbar 15. The neutral contacts NUn, NVn, NWn are all connected to a neutral contact busbar 11, which in this embodiment forms a star connection.A contact area 17 is defined as a sector of the circumference of the stator 1 occupied by the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn on the connection side 10. The contact area 17 extends over a quarter of the circumference of the stator 1, or over 12 of the 48 slots. The span of the contact area 17 is minimized and thus even more compact than in . Fig. 4 shown.

[0045] Hairpin winding 3, which defines the three phase windings, has four parallel branches per phase U, V, W. The phase contacts are designated U1, U2, U3, U4, V1, V2, V3, V4, W1, W2, W3, W4 and the neutral contacts are designated NU1, NU2, NU3, NU4, NV1, NV2, NV3, NV4, NW1, NW2, NW3, NW4. The phase contacts designated U1, U2, V1, V2, W1, W2 and the neutral contacts designated NU3, NU4, NV3, NV4, NW3, NW4 are arranged in the outermost layer L8 of the radially adjacent layers Li, and the phase contacts designated U3, U4, V3, V4, W3, W4 and the neutral contacts designated NU1, NU2, NV1, NV2, NW1, NW2 are arranged in the innermost layer L1 of the radially adjacent layers Li. In the illustrated embodiment, the phase contacts Un, Vn, Wn are evenly distributed between the outermost layer Lz and the innermost layer L1.The phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn are arranged in a compact manner in a sector of the circumference of the stator 1, the contact area 17. The radially extending rows of end sections 8 generally correspond to the 48 slots of the stator 1, assuming that the end sections 8 are all offset by the same radial distance clockwise or counterclockwise. In this embodiment, the contact area 17 extends over 12 of the 48 slots or over a circular sector of 90° of the stator 1. The contact area 17 does not contain any slots or rows with end sections 8 with the shorter spot-welded electrical connections 16. All welding processes on the connections of the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn on the busbars 11, 12, 14, 15 are limited to a quarter of the stator circumference.

[0046] In Fig. 11 is an enlarged section of Fig. 9 with the neutral contact busbar 11, the U-phase busbar 12, the V-phase busbar 14 and the W-phase busbar 15 in an exploded view. In Fig. 12 is the detail from Fig. 11 in perspective view, with the neutral contact busbar 11, the U-phase busbar 12, the V-phase busbar 14 and the W-phase busbar 15 in their respective installation positions when installed at the connecting end 10 of the hairpin winding 3.

[0047] In Fig. Figure 13 shows an example of a winding structure diagram for a stator embodiment according to the invention. The assignment of the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn of the hairpin winding to the slots 5 of the stator is described. The matrix represents the slots 5 in columns and the layers L1 to L8 in rows. The top row shows the slots numbered 1 to 48. The left column shows the layer designations L1 to L8. The matrix is ​​divided into three parts, which are to be understood sequentially according to the order of the slot numbers. The labels of the matrix elements illustrate the path of each branch through the slots and layers.The labeling is in the form "Ux_y" for the U-phase branches, "Vx_y" for the V-phase branches, and "Wx_y" for the W-phase branches, where x denotes the branch number and y is a consecutive number from the respective phase contacts Un, Vn, Wn to the respective neutral contacts NUn, NVn, NWn of each branch. The matrix elements with the four U-phase phase contacts are accordingly labeled U1_1, U2_1 in the outermost layer L8 and U3_1, U4_1 in the innermost layer L1 in slots 1 and 2. The four V-phase phase contacts are accordingly labeled V1_1, V2_1 in the outermost layer L8 and V3_1, V4_1 in the innermost layer L1 in slots 5 and 6. The four phase contacts of the W phase are accordingly labeled W1_1, W2_1 in the outermost position L8 and W3_1, W4_1 in the innermost position L1 in slots no. 9, 10, 45 and 46.

[0048] The structure of the hairpin winding 3 is described using the first branch of the U-phase as an example. The leg section 6 (see Fig. 3), which forms the phase contact U1, is arranged in slot no. 1 in the outermost layer L8 and bears the matrix element designation U1_1. The second leg 6 of the same hairpin conductor 4 is located in the adjacent negative pole of the U-phase winding, in slot no. 7 in the adjacent layer L7, with the matrix element designation U1_2. The distance from slot no. 1, layer L8, to slot no. 7, layer 7, is the slot spacing of the hairpin conductor 4. The slot spacing of six slots 5 in the circumferential direction and one layer Li in the axial direction is identical for all hairpin conductors 4 of the hairpin winding 3. The course of the first branch of the U-phase winding is described further as an example. The end section 8 of the leg section 6, designated U1_2, is spot-welded at the connection end 10 to the adjoining second hairpin conductor 4, namely with U1_3 in slot no. 13, outermost layer L8 in the following positive pole of the U-phase winding, and with U1_4 in slot no.19, adjacent layer L7 in the following negative pole of the U-phase winding. The latter end section 8 of the leg section 6 is spot-welded to the third hairpin conductor 4, designated U1_5, in slot no. 25, layer L8, positive pole, and U1_6, in slot no. 31, layer L7, negative pole, etc. It should be noted that the slot spacing of six slots in the circumferential direction and one layer Li in the axial direction is also spanned at the connection end 10 by the offset end sections 8, with both end sections 8 of each spot-welded electrical connection 16 being offset by half the slot spacing (see . Fig. 9). The fourth hairpin conductor 4 returns to the negative U-phase pole with the leg section designated U1_8 in slot no. 43. A second circuit of the winding around the stator core 2 begins with the fifth hairpin conductor 4, again in slot no. 1, now in the next layer L6, designated U1_9. The branch continues, alternating between layers L6 and L5 and, after another full circuit of the winding around the stator core 2, changes to layers L4 and L3. The last circuit of the winding in the inner layers L2 and L1 ends with the sixteenth hairpin conductor 4 of the branch. The designation U1_32 indicates the position of the leg section 6 with the neutral contact NU1 at its end section 8 in slot no. 43 in the innermost layer L1. It should be noted that the neutral contact NU1 is not located at the circumferential position of slot No. 43, but at the circumferential position of slot No. 46 due to its offset over half the slot distance.Furthermore, it should be noted that the end section 8 of the phase contact U1 of the same branch is set in the opposite direction in the outermost layer L8 and thus also has the circumferential position of the groove No. 46.

[0049] The other branches with the phase contacts U2, V1, V2, W1, W2 in the outermost layer L8 are routed parallel to the branch described above, starting in slots 2, 5, 6, 9, and 10, respectively. The slot spacing of the hairpin conductors 4 is identical. The branches ending in the neutral contacts NU3, NU4, NV3, NV4, NW3, NW4 in the outermost layer L8 must also be routed parallel to avoid crossing the branches and to ensure uniform slot spacing of the hairpin conductors 4. Accordingly, the branches starting at the phase contacts U3, U4, V3, V4, W3, W4 in the innermost layer L1 are wound around the stator core 2 in the opposite direction of rotation to the branches with the phase contacts U1, U2, V1, V2, W1, W2 in the outermost layer L8. Starting from the innermost layer L1, the branches are routed toward the slots with lower consecutive numbers. For example, the third branch of the W-phase winding begins with phase contact W3 in slot number 1.45 in the innermost layer L1, designated W3_1. The second leg 6 of the same hairpin conductor 4 is located in the adjacent negative pole of the W-phase winding in slot 39 of the adjacent layer L2, designated W3_2. The distance from slot 45, layer L1, to slot 39, layer 2, is the uniform slot spacing of the hairpin conductors 4, consisting of six slots in the circumferential direction and one layer Li in the axial direction. Thus, all branches are routed in parallel, with the phase contacts Un, Vn, Wn and the neutral contacts NUn, NVn, NWn evenly distributed between the innermost layer L1 and the outermost layer L8.

[0050] The phase contacts Un, Vn extend in pairs from slots referred to as common phase contact slots 51. The phase contacts U1 and U3 extend from the common phase contact slot 51 with the slot number 1. One skilled in the art will recognize that the phase contacts Un, Vn extending in pairs from a common phase contact slot 51 are not arranged in the same row at the connecting end 10, since the end sections 8 in the outermost layer L8 are set in the opposite direction of rotation to the end sections 8 in the innermost layer L1. In the illustrated embodiment, the phase contacts U1 and U3 each have a circumferential set of six rows or slots, i.e., by the slot pitch of the hairpin conductors. In the illustrated embodiment, several pairs of the phase contacts Un, Vn of the parallel branches extend in pairs from several adjacently arranged common phase contact slots 51.The common phase contact slots 51 of the U-phase winding are slots Nos. 1 and 2, and the common phase contact slots 51 of the V-phase winding are slots Nos. 5 and 6. The phase contacts Wn of the W-phase winding are staggered, with W1 and W2 extending from slots Nos. 9 and 10, which are referred to as first staggered phase contact slots 52, and W3 and W4 extending from slots Nos. 45 and 46, which are referred to as second staggered phase contact slots 53.

[0051] The neutral contacts NU1, NU2, NV1, and NV2 of the parallel branches of the respective phase windings U, V extend from first offset neutral contact slots 57 in the innermost layer L1, and the neutral contacts NU3, NU4, NV3, and NV4 extend from second offset neutral contact slots 58 in the outermost layer LZ. The first offset neutral contact slots 57 are circumferentially offset relative to the second offset neutral contact slots 58. The first offset neutral contact slots 57 of the U-phase winding are slots Nos. 43 and 44, which are offset relative to the second offset neutral contact slots 58 of the U-phase winding in slots Nos. 7 and 8. The first offset neutral contact slots 57 of the V-phase winding are slots 47 and 48, which are offset relative to the second offset neutral contact slots 58 of the V-phase winding in slots 11 and 12. The offset is twelve slots in each case.The neutral contacts NW1, NW2, NW3, NW4 of the W-phase winding extend from common neutral contact slots 56, which in this embodiment are slots Nos. 3 and 4.

[0052] The common phase contact slots 51, the common neutral contact slots 56, the first offset neutral contact slots 57, the second offset neutral contact slots 58, the first offset phase contact slots 52, and the second offset phase contact slots 53 together define a contact slot region 18 that extends circumferentially over a portion of the total number of slots. In this embodiment, the contact slot region 18 extends from slot number 43 to slot number 12, i.e., over 18 slots. None of the slots of the contact slot region is occupied by a non-terminal end portion 8 in the outermost layer L8 or the innermost layer L1. The contact slot region 18 is larger than the contact region 17 counted in slots by the slot spacing of the hairpin conductor of six slots (cf. Fig. 9). Reference symbols: 1 stator 2 Stator core 3 hairpin turns 4 hairpin ladders 5 grooves 51 Common phase contact groove 52 First offset phase contact groove 53 Second offset phase contact groove 56 Common neutral contact groove 57 First offset neutral groove 58 Second offset neutral groove 6 leg section 7 Head section 8 end sections 9 shank end 10 Connection end 11 Neutral busbar 12 U-phase busbar 14 V phase busbar 15 W phase busbar 16 Spot welded connection 17 Contact area 18 Contact groove area 19 Bridge A Longitudinal axis Li Layers U, V, W phase windings Un phase contacts, U-phase winding Vn phase contacts, V-phase winding Wn phase contacts, W-phase winding NUn neutral contacts, U-phase winding NVn neutral contacts, V-phase winding NWn neutral contacts, W-phase winding

Claims

[1] Stator (1) for an electrical machine, comprising: a stator core (2) having a plurality of slots (5) and a hairpin winding (3); wherein the hairpin winding (3) comprises hairpin conductors (4) with two leg sections (6) which are connected at a head section (7), wherein a slot distance between the two leg sections (6) is defined by the head section (7), wherein the slot distance of each of the hairpin conductors (4) is identical; wherein the leg sections (6) of the hairpin conductors (4) are received in the slots (5) in at least two radially adjacent layers (Li), wherein the head sections (7) protrude from the stator core (2) at an insertion end (9) and end sections (8) of the leg sections (6) protrude from the stator core (2) opposite the head sections (7) at a connection end (10); wherein the hairpin winding (3) defines at least three phase windings (U, V, W), each phase winding having at least one branch, each branch of each phase winding having a phase contact (Un, Vn, Wn) formed at one of the end portions (8) for connection to a phase busbar, and each branch of each phase winding having a neutral contact (NUn, NVn, NWn) formed at one of the end portions (8) for connection to a neutral busbar, wherein the phase contacts and the neutral contacts are all arranged at the connecting end (10) of the hairpin winding (3) in at least one of an outermost layer (Lz) of the radially adjacent layers (Li) and an innermost layer (L1) of the radially adjacent layers (Li), wherein each phase winding has a plurality of parallel branches and wherein at least one pair of phase contacts (Un, Vn, Wn) of the parallel branches of at least one phase winding both extend from a common phase contact groove (51), wherein a first half of the phase terminals (Un, Vn, Wn) of the parallel branches of at least one phase winding extends in the outer layer (LZ) from at least one first offset phase contact groove (52), and wherein a second half of the phase terminals (Un, Vn, Wn) of the at least one phase winding extends in the inner layer (L1) from at least one second offset phase contact groove (53), and wherein the at least one first offset phase contact groove (52) is offset in the circumferential direction relative to the at least one second offset phase contact groove (53), wherein at least one pair of neutral contacts (NUn, NVn, NWn) of the parallel branches of at least one of the phase windings both extend from a common neutral contact groove (56), and wherein a first half of the neutral contacts (NUn, NVn, NWn) of the parallel branches of at least one phase winding in the innermost layer (L1) extends from at least one first offset neutral contact slot (57), and wherein a second half of the neutral contacts (NUn, NVn, NWn) of the at least one phase winding in the outermost layer (LZ) extends from at least one second offset neutral contact slot (58), and wherein the at least one first offset neutral contact slot (57) is offset in the circumferential direction relative to the at least one second offset neutral contact slot (58). [2] Stator according to claim 1, wherein a contact area (17) is defined as a sector of a circumference of the stator (1) occupied by the phase contacts (Un, Vn, Wn) and the neutral contacts (NUn, NVn, NWn) at the connection end (10), and wherein a span of the contact area (17) over a circumference of the stator (1) is minimized. [3] Stator according to one of the preceding claims, wherein a plurality of pairs of phase contacts (Un, Vn, Wn) of the parallel branches of the at least one phase winding extend in pairs from a plurality of adjacently arranged common phase contact grooves (51). [4] Stator according to one of the preceding claims, in which a plurality of pairs of neutral contacts (NUn, NVn, NWn) of the parallel branches of the at least one phase winding extend in pairs from a plurality of adjacently arranged common neutral contact slots (56). [5] Stator according to one of the preceding claims, wherein the common phase contact slots (51), the first offset phase contact slots (52), the second offset phase contact slots (53), the common neutral contact slots (56), the first offset neutral contact slots (57) and the second offset neutral contact slots (58) together define a contact slot area which extends circumferentially over a fraction of the total number of slots (5). [6] Stator according to one of the preceding claims, wherein the contact groove region extends over a contiguous region of adjacent grooves (51, 52, 53, 56, 57, 58) in which at least one phase contact or at least one neutral contact is arranged. [7] Stator according to one of the preceding claims, wherein each phase winding has a plurality of parallel branches, wherein at least the phase contact of a first branch and the neutral contact of a second branch are arranged in one of the outermost layer (Lz) and the innermost layer (L1), wherein the first branch and the second branch are connected to each other on the respective opposite layer of the outermost layer (Lz) and the innermost layer (L1). [8] Stator according to claim 1, wherein the phase contacts (Un, Vn, Wn) are evenly distributed between the outermost layer (Lz) and the innermost layer (L1).

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