Stator for an electric machine, electric machine for a vehicle and electric drive for a vehicle

Abstract

Stator (1) for an electric machine (102), the stator (1) comprising a stator core (2) having axial first and second face sides (4, 5) and an axial second face side (5) being opposite to the first face side (4) and forming a plurality of slots (6) and a stator winding (7) having 2·P poles and comprising N phase windings (U, V, W); – the stator winding (7) is formed by segmented conductors (8a-d, 8c', 8c''), which form leg portions (9, 9', 9'', 9a-f, 15, 16) and connection portions (10a, 10b) each connecting two leg portions (9, 9', 9'', 9a-f, 15, 16); – the slots (6) are subdivided into first to L-th layers (20a-f), in each slot (6) one of the layers (20a-f) forms an accommodation position for one of the leg portions (9, 9', 9'', 9a-f, 15, 16), the (2·i)-th and the (2·i–1)-th layers (20a-f) forming an i-th double layer (21a-c) for all 1 ≤ i ≤ L / 2; – for each pole and phase winding (U, V, W), the slots (6) form one winding zone (22, 22a, 22b) extending, in each layer (20a-f), over q slots (6) for con- taining L·q contiguous accommodation positions accommodating leg por- tions (9, 9', 9'', 9a-f, 15, 16) of the same phase winding (U, V, W); – each phase winding (U, V, W) comprises first to A-th partial windings (14a- d), wherein A ≥ q+1 and A ≠ x·q, x being an integer; – for each phase winding (U, V, W), one of the winding zones (22, 22a, 22b) is a start winding zone (22a) and one of the winding zones (22, 22a, 22b) is an end winding zone (22b), wherein the start leg portions (15) of the partial windings (14a-d) are disposed in the start winding zone (15) and the end leg portions (16) are disposed in the end winding zone (22b).

Description

[0001] Stator for an electric machine, electric machine for a vehicle and electric drive for a vehicle

[0002] The present invention relates to a stator for an electric machine. Aside, the invention relates to an electric machine for a vehicle and to an electric drive for a vehicle.

[0003] In automotive applications, stators with a stator winding made of segmented conductors are highly preferred design in electric machines. Therein, the stator winding may comprise a number of phase windings, which each comprise multiple partial windings. The partial windings may be connected in parallel and / or in series for forming the phase winding.

[0004] Exemplarily, DE 10 2022 133 495 A1 discloses a stator for an electric machine. The stator comprises a stator core, which has a longitudinal axis, an axial first face side and an axial second face side being opposite to the first face side and which forms a plurality of slots extending from the first face side to the second face side, and a stator winding having eight poles and comprising a three phase windings. Each phase winding is formed by segmented conductors, which comprise leg portions disposed inside the slots and connections portions connecting two leg portions at the face sides electrically. The slots forms, for each phase winding, eight winding zones and are subdivided into first to eighths layers, which are numbered according to their sequence in radial direction, wherein in each slot one of the layers forms an accommodation position for one of the leg portions. Each winding zone extends of two slots. The stator winding comprises, for each phase winding, two current paths, which are formed by multiple ones of the leg portions and multiple ones of the connections portions that connect the multiple ones of the leg portions. First and last leg portions of each current path are disposed in directly adjacent winding zones of the same phase winding. Having start leg portions of each partial winding in the same start winding zone and end leg portions of each partial winding in the same end winding zone, which is a directly adjacent winding zone of the same phase winding, facilitates as well the connection of the partial windings among each other as well as the connection of the phase winding to an external voltage source. However, in the design of DE 10 2022 133 495 A1 , this is restricted to the number slots per pole and phase being equal to the number of partial windings or current paths, respectively.

[0005] It is an object of the present invention, to provide a simple possibility for connecting partial windings of a phase winding of a stator winding for more complex stator windings.

[0006] The above object is solved by a stator for an electric machine, the stator comprising a stator core, which has a longitudinal axis, an axial first face side and an axial second face side being opposite to the first face side and which forms a plurality of slots extending from the first face side to the second face side, and a stator winding having a number 2-P of poles and comprising a number N of phase windings, wherein N > 2; the stator winding is formed by segmented conductors, which form leg portions each being arranged inside one of the slots and connection portions each connecting two of the leg portions at one of the face sides in an electrically conductive manner; the slots are subdivided into first to L-th layers, which are numbered according to their sequence in radial direction, wherein in each slot one of the layers forms an accommodation position for one of the leg portions, the (2-i)-th and the (2-i— 1 )-th layers forming an i-th double layer for all 1 < i < L / 2, wherein L > 4 is an even number; for each pole and phase winding, the slots form a winding zone extending over all L layers and in each layer over q slots for containing L-q contiguous accommodation positions accommodating leg portions of the same phase winding, wherein q > 2 is an integer; each phase winding comprises first to A-th partial windings, each partial winding forming a current path of a plurality of the leg portions connected in series from a start leg portion of the leg portions to an end leg portion of the leg portions, wherein A > q+1 and A + x-q, x being an integer; for each phase winding, one of the winding zones is a start winding zone and one of the winding zones is an end winding zone, exactly one winding zone of each of the other phase windings being arranged circumferentially between the start winding zone and the end winding zone, wherein the start leg portions of the partial windings of a respective one of the phase windings are disposed in the start winding zone and the end leg portions of the partial windings of the respective one of the phase windings are disposed in the end winding zone.

[0007] The stator for an electric machine according to the invention comprises a stator core and a stator winding. The stator core has a longitudinal axis, an axial first face side and an axial second face side. The second face side is opposite to the first face side. The stator core forms a plurality of slots. The slots extend from the first face side to the second face side.

[0008] The stator winding has a number 2-P of poles. The stator winding comprises a number N of phase windings. Therein, N > 2. The stator winding is formed by segmented conductors. The segmented conductors form leg portions. Each leg portion is arranged inside one of the slots. The segmented conductors further form connection portions. Each connection portion connects two of the leg portions at one of the face sides in an electrically conductive manner.

[0009] The slots are subdivided into first to L-th layers. The layers are numbered according to their sequence in radial direction. In each slot one of the layers forms an accommodation position for one of the leg portions. The (2-i)-th and the (2-i— 1 )-th layers form an i-th double layer for all 1 < i < L / 2. Therein, L > 4 is an even number. For each pole and phase winding, the slots form one winding zone. The winding zone extends over all L layers and, in each layer, over q slots for containing L-q contiguous accommodation positions. The accommodation positions accommodate leg portions of the same phase winding. Therein, q > 2 is an integer.

[0010] Each phase winding comprises first to A-th partial windings. Each partial winding forms a current path of a plurality of the leg portions connected in series from a start leg portion of the leg portions to an end leg portion of the leg portions.

[0011] Therein, A > q+1 and A + x-q, x being an integer.

[0012] For each phase winding, one of the winding zones is a start winding zone and one of the winding zones is an end winding zone. Exactly one winding zone of each of the other phase windings is arranged circumferentially between the start winding zone and the end winding zone. The start leg portions of the partial windings of a respective one of the phase windings are disposed in the start winding zone. The end leg portions of the partial windings of the respective one of the phase windings are disposed in the end winding zone.

[0013] The present invention addresses a stator winding, in which each phase winding comprises a number A of partial windings, which is larger than the number q of slots in each layer of the winding zones and a non-multiple of q. Therein, the number q can also be understood as the number of slots per pole and phase of the stator winding. As the start and end leg portions of all partial windings of a respective phase winding are disposed in the circumferentially adject start and end winding zones and, thus, in relative proximity, a connection of the partial windings does not have to expand over more than two winding zones for the same phase winding. Advantageously, the stator according to the invention allows to connect the partial windings in a space-efficient manner, when the stator allows high performance and high-power operation due to a relatively large number of partial windings.

[0014] Regarding this invention, the terms “axially”, “axial direction”, “radially”, “radial direction”, “circumferentially” and “circumferential direction” refer to the longitudinal axis of the stator core.

[0015] The stator core may be formed by a plurality of axially stacked and / or electrically isolated laminations made of metal. Typically, the slots each extend axially through the stator core. In particular, the slots are distributed circumferentially over the stator core. Regarding the layers, it is preferred, that the first layer is a radially outer, in particular the radially outermost, layer. Especially, exactly L leg portions are disposed in each slot and / or each accommodation space accommodates exactly one of the leg portions.

[0016] The stator may be configured such that, when the phase windings are supplied with an N-phase AC current, the current through the leg portions disposed in the same winding zone has the same direction.

[0017] Each winding zone may extend over L layers and q slots. Thereby, a straight stator winding may be formed. However, it is also possible that each winding zone extends over L layers and more than q slots. In this case, a skewed stator winding can be realized.

[0018] Preferably, q+1 < A < (2-q)-1 and / or q is an integer.

[0019] The stator may comprise a connection device, configured to connect the partial windings of each phase in parallel and / or in series and / or to provide a phase terminal for each phase winding and / or to realize a star or delta connection of the phase windings.

[0020] According to a preferred design, the start leg portions of q of the partial windings of the respective one of the phase windings are arranged in the y-th double layer, wherein 1 < y < L / 2. That is, the y-th double layer accommodates as many start leg portions as possible so that the start leg portions are disposed very close to each other. In a particular convenient design, y equals 1 . That is, the q of the partial windings are arranged in the first doble layer, which allows to connect the partial windings from the radial periphery of a winding head formed at the face side. The connection of the q of the partial windings can be further simplified, when the start leg portions of the q of the partial winding are arranged in the same layer of the y-th double layer. In particular, the same layer is the first layer.

[0021] Likewise, the end leg portions of the q of the partial winding may are arranged in the y-th double layer.

[0022] Further, the start leg portion or the start leg portions of (A-q) of the partial windings may be arranged in the (y+1 )-th or (y-1 )-th double layer. That is, the (A-q) of the partial windings are disposed in a radially adjacent double layer with regard to the q of partial windings. With similar advantage as described afore, the end leg portion or the end leg portions of the (A-q) of the partial windings may be arranged in the y-th double layer.

[0023] In the following, a preferred windings scheme that allows to make a symmetrical stator winding for the stator according to the invention is described.

[0024] According to the preferred winding scheme of the stator according to the invention, in each partial winding, the leg portions are arranged in first to (2-P-q-L / A) ones of the accommodation positions defining a leg portion pattern of accommodation positions for the partial winding, the numbering of the accommodation spaces corresponding to the sequence of the leg portions along the current path and the start leg portion being arranged in the first accommodation space.

[0025] Preferably, the leg portion pattern for the (j+1 )-th partial winding corresponds to the leg portion pattern of the first partial winding shifted by 2-N-q-j slots in a predefined orientation of the circumferential direction for all 1 < j < A-1 , the first accommodation space of the (j+1 )-th partial winding being the (1 +2-j)-th accommodation space of the first partial winding. In other words, the leg portion pattern of each of the partial windings can be brought in congruence with the other leg portion patterns by a circumferential shift. This allows to form, for each partial winding of the same phase winding, congruent “loops”, which are opened between the start and end winding zones.

[0026] With regard to the preferred winding scheme of the stator according to the invention, it is further possible that the current path of the first partial winding comprises first to L-th subpaths numbered according to their sequence along the current path, the first subpath including the start leg portion, wherein each subpath includes first to (3-P / 2)-th ones of the leg portions being arranged in alternating layers of the same double layer. That is, in each double layer, each partial winding occupies only a fraction of the winding zones of the phase winding. Further, each subpath may be considered as a wave winding within one of the double layers.

[0027] More preferably, the leg portions of the k-th subpath are arranged in k-th double layer for all 1 < k < L / 2 and the leg portions of the l-th subpath are arranged in the (L+1 -l)-th double layer.

[0028] It is further preferred that the first to (L / 2)-th subpaths extend about the longitudinal axis in a first orientation of the circumferential direction and the [(L / 2)+1 ]-th to L-th subpath extend about the longitudinal axis in a second orientation of the circumferential direction, the second orientation being counter-oriented with regard to the first orientation. E.g. the first orientation is clockwise or counter-clockwise when looking at the first face side.

[0029] Alternatively or additionally, the first leg portion of the first subpath and the (3-P / 2)- th leg portion of the L-th subpath are arranged in the same layer.

[0030] Alternatively or additionally, the (3-P / 2)-th leg portion of the (L / 2)-th subpath and the first leg portion of the [(L / 2)+1 )]-th subpath are arranged in the same layer.

[0031] According to a preferred design, each winding zone is subdivided into first to q-th subzones, wherein the m-th subzone includes the m-th of first to q-th accommoda- tion position of each layer, the first to m-th accommodation positions being numbered according to their sequence in the circumferential direction, in particular according to the second orientation of the circumferential direction, wherein for all 1 < n < q.

[0032] Preferably, the o-th phase winding corresponds to the first phase winding being shifted by (o-1 )-q slots for all 2 < o < N.

[0033] It is possible that the segmented conductors are each realized by U-type segmented conductors, each including two leg portions, a head portion forming the connection portion that connects the two leg portions at the first face side and, for each leg portion, a connection section extending from the leg portion out of the stator core at the second face side for forming the connection portions.

[0034] According to a preferred alternative implementation, the start leg portion and the end leg portion of each partial winding are realized by an l-type segmented conductor including the leg portion, a connection section extending from the leg portion out of the stator core at the second face side and a terminal portion extending from the leg portion out of the stator core at the first face side, wherein segmented conductors forming the current path between the start leg portion and the end leg portion are each realized by an U-type segmented conductor including two leg portions, a head portion forming the connection portion that connects the two leg portions at the first face side and, for each leg portion, a connection section extending from the leg portion out of the stator core at the second face side and being connected to the connection section of another segmented conductor for forming the connection portion that connects the leg portion and one of the leg sections of the other segmented conductor

[0035] Therein, leg portions that are realized by U-type segmented conductors and that are disposed in different layers can be implemented by first type segmented conductors, which extend axially up to a first axial position having a predetermined distance to the first face side, wherein the (3-P / 2)-th leg portion of the (L / 2)-th subpath and the first leg portion of the [(L / 2)+1 )]-th subpath, which are arranged in the same layer, can be realized by a second type segmented conductor having a first leg portion and a second leg portion and extending axially up to a second axial position having a second predetermined distance to the first face side, the second predetermined distance being larger than the first predetermined distance.

[0036] Preferably, the head portion of each second type segmented conductor comprises: a first combined bent between the first connection point and the second connection point, beyond which the head portion extends in a skewed manner into a first orientation of the circumferential direction and into the axial direction away from the first face side; a turnaround bent between the first combined bent and the second connection point, beyond which the head portion extends circumferentially along a second orientation of the circumferential direction being opposite to the first orientation; a first radial bent being directed radially outwardly between the turnaround bent and the second connection point; a second radial bent being directed radially inwardly between the first radial bent and the second connection point; a second combined bent between the second radial bent and the second connection portion, beyond which the head portion extends in a skewed manner into the second orientation of the circumferential direction and into the axial direction towards the first face side.

[0037] Therein, between the first combined bent and the first radial bent, the head can form a first head portion section, which extends in the radial direction up to a first radial position. Between the turnaround bent and the second combined bent, the head portion can form a second head portion section, which extends at the second axial position. Beyond the second radial bent, the head portion can form a third head portion section, which extends at a second radial position being radially more outwardly than the first radial position.

[0038] Preferably, circumferentially adjacent pairs of the second type segmented conductors of different phase windings are arranged such that the second head portion section of one of the second type segmented conductors of the pair extends partially along the third head portion section of the other one of the second type segmented conductors of the pair.

[0039] Beyond its second combined bent, the head section of the other one of second type segmented conductors of the pair may extend partially between the first head portion section of the one of the second type segmented conductors and the first axial face side.

[0040] The head portion of each second type segmented conductor may further comprise a third radial bent being directed radially inwardly between the second combined bent and the second connection point; wherein the third head portion is formed between the second radial bent and the third radial bent.

[0041] The head portion of each second type segmented conductor may further comprise: a fourth radial bent directed radially outwardly between the third radial bent and the second connection point; wherein, between fourth radial bent and the second connection point, the head portion forms a fourth head portion section, which extends at a third radial position being radially more inwardly than the second radial position.

[0042] The head portion of each second type segmented conductor may further comprise: a third combined bent, beyond which the head portion extends at the circumferential position of the second connecting point axially towards the second connecting point.

[0043] The above object is further solved by an electric machine for a vehicle, the electric machine comprising a stator as described afore and a rotor being mounted rotatably with regard to the stator. The electric machine may be a synchronous motor. The rotor may be permanently or electrically excited. Alternatively, the electric machine may be an induction motor.

[0044] The above object is further solved by an electric drive for a vehicle, the electric drive comprising an electric machine as described afore, a gearbox and an inverter configured to supply an N-phase AC current to the stator winding. Preferably, the electric machine, the gearbox and the inverter are disposed in an integral housing.

[0045] The electric vehicle may be a battery-electric vehicle. Alternatively, the electric vehicle comprises a further combustion engine and is a hybrid vehicle.

[0046] All statements referring to the stator according to the invention apply analogously to the electric machine and the electric drive so that the above-mentioned advantages of the inventive inverter may be achieved by them as well.

[0047] Further details and advantages of the invention are disclosed in the following, wherein reference is made to the enclosed drawings. The drawings show schematically:

[0048] Fig. 1 a principle drawing of an embodiment of a stator according to the invention;

[0049] Fig. 2 a block diagram of the stator winding according to the embodiment;

[0050] Fig. 3 a winding scheme of one of the phase windings according to the embodiment;

[0051] Fig. 4 a detailed winding scheme of the first to third subpaths of the first partial winding of the phase winding shown in Fig. 3; Fig. 5 a detailed winding scheme of the fourth to sixth subpaths of the first partial winding of the phase winding shown in Fig. 3;

[0052] Fig. 6 principle drawings of segmented conductors of the embodiment;

[0053] Fig. 7 a detailed view of the stator of the embodiment;

[0054] Fig. 8 a top view on a second type segmented conductor;

[0055] Fig. 9 a side view on a second type segmented conductor;

[0056] Fig. 10 a top view of two second type segmented conductors; and

[0057] Fig. 11 a principle drawing of a vehicle with an embodiment of an electric drive according to the invention.

[0058] Fig. 1 a principle drawing of an embodiment of a stator 1 .

[0059] The stator 1 comprises a stator core 2, which has a longitudinal axis 3, an axial first face side 4 and an axial second face side 5 being opposite to the first face side 4. The stator core 2 forms a plurality of slots 6, of which only three are shown for illustration purposes in Fig. 1 . The slots 6 extend from the first face side 4 to the second face side 5. In particular detail, the stator core 2 is formed by a plurality of axially stacked and isolated metal laminations (not shown).

[0060] Further, the stator 1 comprises a stator winding 7, which comprises a number N of phase windings U, V, W. In the present embodiment N = 3 phase windings U, V, W are provided. The stator winding 7 is formed by segmented conductors 8a-d, of which only segmented conductors 8a, 8b are depicted schematically in Fig. 1 . The segmented conductors 8a-d form leg portions 9 each being arranged inside one of the slots 6. Further, the segmented conductors form connection portions 10a, 10b each connecting two of the leg portions 9 at one of the face sides 4, 5 in an electrically conductive manner. The connection portions 10a, 10b form winding heads 12, 13 at a respective face side 4, 5 of the stator core.

[0061] In detail, segmented conductors 8a, c, d which are U-type segmented conductors and segmented conductors 8b, which are l-type segmented conductors, are provided. The U-type segmented conductors 8a, c, d each comprise two leg portions 9 and a head section 14, which forms one of the connection portions 10a. The leg portions 9 of the U-type segmented conductors 8a, c, d are formed in an integral manner with the connection portion 10a or head section 1 1 a, respectively, that connects the two leg portion 9 at the first face side 4. The l-type segmented conductors 8b comprise one leg portion 9 and a terminal section 1 1 b at the first face side 4. At the second face side 5, the segmented conductors 8a-c comprise a connection section 1 1 c, which extend from a respective leg portion 9. The connection portions 10b are formed by mechanically and electrically connecting the connection section 1 1 c of a pair of segmented conductors 8a-c. Therein, in Fig. 1 only one U-type segmented conductor 8a is shown entirely, which is connected with a partially depicted further U-type segmented conductor 8a.

[0062] Fig. 2 is a block diagram of the stator winding 7 according to the embodiment.

[0063] Each phase winding U, V, W comprises first to A-th partial windings. In the present embodiment, A = 4 partial winding 14a, 14b, 14c, 14d are provided. Each partial winding 14a-d forms a current path of a plurality of the leg portions 9 connected in series from a start leg portion 15 of the leg portions 9 and an end leg portion 16 of the leg portions 9.

[0064] In particular detail, each current path comprises first to L-th subpaths. In the present embodiment, L = 6 subpaths 16a, 16b, 16c, 16d, 16e, 16f are provided. The subpaths 16a-f are numbered according to their sequence along the current path, where in the first subpath 16a includes the start leg portion 15 and the L-th ( = sixth) subpath 16f includes the end leg portion 16. For reasons of simplicity, only the subpaths 16a-f of the first partial winding 14a of the phase winding U is provided with reference numerals.

[0065] By means of a terminal device 17, which is shown schematically in Fig. 1 , the partial windings 16a-f of each phase winding U, V, W are connected in parallel. The terminal device 17 further forms phase connection 18u, 18v, 18w for each phase winding U, V, W and a neutral point 19 of a Y-connection of the phase windings U, V, W.

[0066] Fig. 3 is a winding scheme of one of the phase windings U according to the embodiment. Therein, an upper table in Fig. 3 shows accommodation positions for the leg portions 9 of the phase windings U, V, W in different shadings. The four lower tables show respective windings schemes of each partial winding 14a-d of the phase winding U. In the tables, each cell denotes one accommodation position. Further, each column of one of the tables corresponds to one slot 6. Between the upper table and the lower tables, a slot numbering is depicted.

[0067] In Fig. 3, connection portions 10a at the first face side 4 are denoted by dashed arrows between the accommodation positions, in which the leg portions 9 connection by the connection portion 10a are accommodated. Connection portions 10b at the second face side 5 are denoted by solid lines between the accommodation positions, in which the leg portions 9 connected by the connection portion 10b are accommodated.

[0068] The slots 6 are subdivided into first to L-th layers. In the present embodiment, L = six layers 20a, 20b, 20c, 20d, 20e, 20f are provided, wherein each row of a table corresponds to one of the layers 20a-f. The layers 20a-f are numbered according to their sequence in radial direction. In the present embodiment, the first layer 20a is the radially outermost layer and the L-th (= sixth) layer 20f is the innermost layer. In each slot 6, one of the layers 20a-f forms one accommodation position for one of the leg portions 9. Further, the (2-i)-th and the (2-i— 1 )-th layers 20a-f form an i-th double layer 21 a-c for all 1 < i < L / 2. That is, the first and second layers 20a, b form a first double layer 21 a, the third and fourth layers 20c, d form a second double layer 21 b and the fifth and sixth layers 20e, f form a third double layer 21 c.

[0069] According to the present embodiment, the stator winding comprises 2-P = 8 poles and a number of q = 3 slots per pole and phase. That is, die number of partial windings A = 4 is greater than or equal to q+1 = 4 (A > q+1 ) and not a multiple of q (A + x-q, x being an integer). For each pole and phase winding, the slots form one winding zone 22 extending over all L = 6 layers 20a-f and, in each layer 20a-f, over q = 3 slots for containing L-q = 18 contiguous accommodation positions accommodating leg portions 9 of the same phase winding U, V, W. For reasons of simplicity, only the some winding zones 22 are denoted with a reference numeral in Fig. 3.

[0070] For each phase winding U, V, W, one of the winding zones 22 is a start winding zone 22a and one of the winding zones 22 is an end winding zone 22b. Therein, exactly one winding zone 22 of each of the other phase windings U, V, W is arranged circumferentially between the start winding zone 22a and the end winding zone 22b.

[0071] The start leg portions 15 of the partial windings 14a of a respective one of the phase windings 14a-d are disposed in the start winding zone 22a and the end leg portions 16 of the partial windings 14a-d of the respective one of the phase windings 14a-d are disposed in the end winding zone 22b. In the upper table of Fig. 3, the accommodation positions of the start leg portions 15 for the phase windings U, V, W are denoted by the symbol “x” and the end leg portions 16 are denoted by the symbol “o”. As can be seen, the start leg portions 15, which serve for connecting the partial windings 14a-d are closely arranged over only 8 of the 2-P-N = 24 winding zones 22, therein allowing a very low space consumption for connecting the partial windings 14a-d. In the following, the winding scheme is described with regard to the phase winding U. For the other phase windings W, V, the winding scheme is identical but shifted in the circumferential direction by q slots or 2-q slots, repectively.

[0072] In particular detail, the start leg portions 15 of q = 3 of the partial windings 14a-c of are arranged in the first double layer 21 a (y = 1 ) and, in particular, in the first layer 20a. The start leg portions 15 of the remaining A-q = 1 of the partial windings 14d is arranged in the radially adjacent second double layer 21 b (y+1 = 2), in particular in the third layer 20c. That is, the start leg portions 15 are concentrated in the radial periphery of the stator winding 7 so as to be easily accessed for connecting partial windings 14a-d.

[0073] In further detail, as well the end leg portions 16 of the q = 3 of the partial windings 14a-c as the end leg portion 16 of the A-q = 1 of the partial windings 14d are arranged in the first double layer 21 a. That is, the end leg portions 16 are concentrated in the radial periphery of the stator winding 7 so as to be easily accessed for connecting partial windings 14a-d.

[0074] In each partial winding 14a-d, the leg portions 9 are arranged in first to 2-P-q-L / A = 36 ones of the accommodation positions defining a leg portion pattern of accommodation positions for the partial winding 14a-d. In each of the four lower tables the shaded cells or accommodation positions show the leg portion pattern of the respective partial 14a-d. Therein, the numbering of the first to 36thaccommodation spaces corresponds to the sequence of the leg portions 9 along the current path and the start leg portion 15 being arranged in the first accommodation space. As can be seen, when comparing the leg portion patterns for the partial windings 14a-d, the leg portion pattern for the (j+1 )-th partial winding corresponds to the leg portion pattern of the first partial winding shifted by 2-N-q-j = 18-j slots 6 in a predefined orientation (indicated by arrow 23b) of the circumferential direction for all 1 < j < A-1 = 3. Thein, the first accommodation space of the (j+1 )-th partial winding 14b-d is the (1 +2-j)-th accommodation space of the first partial winding 14a. That is, in the present embodiment, for j = 1 , the leg portion pattern of the second partial winding 14b (j+1 = 2) is shifted by 18 (= 2-N-q-1 ) slots 6 in the predefined orientation over the first partial winding 14a so that the first accommodation space (denoted by 24a) of the second partial winding 14b is the third accommodation space (1 +2-1 ) of the leg portion pattern of the first partial winding 14a, for j = 2, the leg portion pattern of the third partial winding 14c (j+1 = 3) is shifted by 36 (= 2-N-q-2) slots 6 in the in the predefined orientation over the first partial winding 14a so that the first accommodation space (denoted by 24b) of the third partial winding 14c is the fifth accommodation space (1+2-2) of the leg portion pattern of the first partial winding 14a, and for j = 3, the leg portion pattern of the fourth partial winding 14d (j+1 = 4) is shifted by 54 (= 2-N-q-2) slots 6 in the in the predefined orientation over the first partial winding 14a so that the first accommodation space (denoted by 24c) of the fourth partial winding 14d is the seventh accommodation space (1 +2-3) of leg portion pattern the first partial winding 14a.

[0075] Further details of the winding scheme are described in the following with regard to first partial winding 14a. Therein, Fig. 4 and Fig. 5 are each a detailed winding scheme of the first partial winding 14a, wherein Fig. 4 shows first to third subpaths 25a-c of the first partial winding 14a and Fig. 5 fourth to sixth subpaths 25d-f of the first partial winding 14a. For each subpath 25a-f one table is provided in Fig. 4 and Fig. 5, wherein, in correspondence with Fig. 3, each column corresponds to one slot 6, each row corresponds to one layer 20a-f and each cell corresponds to one accommodation position.

[0076] The current path of the first partial winding 14a comprises first to sixth (=L-th) subpaths 25a-f numbered according to their sequence along the current path. The first subpath 25a includes the start leg portion 15 and the sixth (=L-th) subpath 25f includes the end leg portion 16. Each subpath 25a-f includes first to sixth [=(3-P / 2)- th] ones of the leg portions 9a-f being arranged in alternating layers 20a-f of the same double layer 21 a-c.

[0077] The leg portions 9a-f of the k-th subpath 25a-c are arranged in k-th double layer 21 a-c for all 1 < k < L / 2 and the leg portions 9a-f of the l-th subpath 25d-f are arranged in the (L+1 -l)-th double layer L / 2+1 < I < L. That is, in the present embodiment, for k = 1 , the leg portions 9a-f of the first (=k-th) subpath 25a are arranged in the first (=k-th) double layer 21 a, for k = 2, the leg portions 9a-f of the second (=k-th) subpath 25b are arranged in the second (=k-th) double layer 21 b, for k = 3, the leg portions 9a-f of the third (=k-th) subpath 25c are arranged in the third (=k-th) double layer 21 c, for I = 4, the leg portions 9a-f of the fourth subpath 25d are arranged in the third [= (L+1 -l)-th] double layer 21 c, for I = 5, the leg portions 9a-f of the fifth subpath 25e are arranged in the second [= (L+1 -l)-th] double layer 21 b, and for I = 6, the leg portions 9a-f of the sixth subpath 25f are arranged in the first [= (L+1 -l)-th] double layer 21 a.

[0078] Further, the first to third [= (L / 2)-th] subpaths 25a-c extend about the longitudinal axis 3 (see Fig. 1 ) in a first orientation (indicated by arrow 23a) of the circumferential direction and the fourth [= ((L / 2)+1 )-th) to sixth (= L-th) subpaths 25d-f extend about the longitudinal axis 3 in a second orientation (indicated by arrow 23b) of the circumferential direction. In particular detail, the first orientation is the counterclockwise orientation as seen and the second orientation is the clockwise orientation, when looking at the first face side 4 of stator core 2 (see Fig. 1 ). Further in the present embodiment, the second orientation corresponds to the afore-mentioned predefined orientation.

[0079] Moreover, the first leg portion 9a of the first subpath 25a and the sixth [= (3-P / 2)- th] leg portion 9f of the L-th subpath are arranged in the same layer. In the present embodiment this same layer is the first layer 20a. The sixth [= (3-P / 2)-th] leg portion 9f of the third [=(L / 2)-th] subpath 25c and the first leg portion 9a of the fourth [= ((L / 2)+1 ))]-th subpath are arranged in the same layer. In the present embodiment, this same layer is the sixth (= L-th) layer 20f.

[0080] In the present embodiment, each winding zone 22 is subdivided into first to third (=q-th) subzones 26a-c, wherein the m-th subzone 26a-c includes the m-th of first to third (= q-th) accommodation positions of each layer 20a-f. Therein, the first to third accommodation positions being are numbered according to their sequence in the second orientation (see arrow 23b) of the circumferential direction. For all 1 < n < q, the (2n-1 )-th and the (2n)-th leg portion 9a-f of the first to (L / 2)-th subpaths 25a-c are arranged in the n-th subzone 26a-c and the (2n-1 )-th and the (2n)- th leg portions of the [(L / 2)+1 ] to L-th subpaths 25d-f are arranged in the (q-n+1 )-th subzone 26a-c.

[0081] That is, in the present embodiment, for n = 1 , the first [= (2n-1 )-th] leg portion 9a and the second [ (2n)-th] leg portion 9b of the first to third [= (L / 2)-th] subpaths 25a-c are arranged in the first (= n-th) subzone 26a, for n = 2, the third [= (2n-1 )-th] leg portion 9c and the fourth [ (2n)-th] leg portion 9d of the first to third [= (L / 2)-th] subpaths 25a-c are arranged in the second (= n-th) subzone 26b, for n = 3, the fifth [= (2n-1 )-th] leg portion 9e and the sixth [ (2n)-th] leg portion 9f of the first to third [= (L / 2)-th] subpaths 25a-c are arranged in the third (= n-th) subzone 26b, for n = 1 , the first [= (2n-1 )-th] leg portion 9a and the second [= (2n)-th] leg portion 9b of the fourth [= ((L / 2)+1 )] to sixth (=L-th) subpaths 25d-f are arranged in the third [=(q-n+1 )-th] subzone 26c, for n = 2, the third [= (2n-1 )-th] leg portion 9c and the fourth [= (2n)-th] leg portion 9d of the fourth [= ((L / 2)+1 )] to sixth (=L-th) subpaths 25d-f are arranged in the second [=(q-n+1 )-th] subzone 26b, and for n = 3, the fifth [= (2n-1 )-th] leg portion 9e and the sixth [= (2n)-th] leg portion 9f of the fourth [= ((L / 2)+1 )] to sixth (=L-th) subpaths 25d-f are arranged in the first [=(q-n+1 )-th] subzone 26a.

[0082] In the following, further constructive details regarding the segmented conductors 8a-c (see Fig. 1 ) of the present embodiment are described.

[0083] Fig. 6 is a principle drawings of segmented conductors 8a-d of the embodiment.

[0084] The U-type segmented conductors 8a, c, d include first type segmented conductors 8a and second type segmented conductors 8c. In each of the U-type segmented conductors 8a, c, the leg portions 9 are first leg portion 9’ and a second leg portion 9”, each being arranged inside one of the slots 6. As already described above, the head portion 1 1 a is disposed at the first face side 4. The head portion 11 a connects the first leg portion 9’ at a first connection point 50 with the second leg portion 9” at a second connection point 51 , so that the leg portions 9’, 9” are spaced apart circumferentially by a pitch of a number of slots 6.

[0085] In the present embodiment, the first type segmented conductors 8a, which form leg portions 9a-f being disposed in different layers 20a-f of the same double layer 21 a-c (see Fig. 4 and Fig. 5), realize a pitch of N-q-1 , that is a pitch of eight slots 6. The first type segmented conductors 8a, which form leg portions 9a, 9f being disposed in different double layers 21 a-c or connect subsequent first to third [= (L / 2)-th] subpaths 25a-c and subsequent fourth [= ((L / 2)+1 )] to sixth [= L-th] subpaths 26d-f, respectively, realize a pitch of (N+1 )-q-1 , that is, a pitch of eleven slots 6. The second type segmented conductors 8c, which form leg portions 9a, f (see Fig. 4 and Fig. 5) being both disposed in the sixth (= L-th) layer 20f, realize a pitch of N-q slots 6, that is a pitch of nine slots 6.

[0086] None, that a further type of U-type segmented conductors is present in the winding scheme shown in Fig. 3 to Fig. 4, which is not described in further constructive de- tail in here. This refers to the U-type segmented conductors that form the leg portions 9a-f being both disposed in the first layer 20a and that are present in the second to fourth partial windings 14a-d of the phase winding U and in corresponding partial windings of the phase windings V, W. These U-type segmented conductors realize a pitch of N-q slots 6, that is a pitch of nine slots 6.

[0087] Fig. 7 is a detailed view of the stator 1 according to the embodiment as seen towards the inner periphery at the first face side 4.

[0088] The head portions 11 a of the first type segmented conductors 8a extend axially up to a first axial position 52 having a predetermined distance 53 to the first face side 4. The head portions 1 1 a of the second type segmented conductors 8c extending axially up to a second axial position 54 having a second predetermined distance 55 to the first face side 4, which is larger than the first predetermined distance 53.

[0089] Fig. 8 and Fig. 9 each show partially one of the second type segmented conductor 8c, wherein Fig. 8 is a side view and Fig. 9 is a top view.

[0090] The head portion 11 a of each second type segmented conductor 8c comprises a combined bent 56 between the first connection point 50 and the second connection point 51 . Beyond the combined bent 56, the head portion 1 1 a extends in a skewed manner into a first orientation (see arrow 23a) of the circumferential direction and into the axial direction away from the first face side 4 (see Fig. 7).

[0091] Further, the head portion 1 1 a comprises a turnaround bent 57 between the first combined bent 56 and the second connection point 51 . Beyond the turnaround bent 57, the head portion 11 a extends circumferentially along a second orientation (see arrow 23b) of the circumferential direction being opposite to the first orientation. Further, the head portion 1 1 a comprises a first radial bent 58 between the turnaround bent 57 and the second connection point 51 . The first radial bent is directed radially outwardly.

[0092] Further, the head portion 1 1 a comprises a second radial bent 59 between the first radial bent 58 and the second connection point 51 . The second radial bent 60 is directed radially inwardly.

[0093] Further, the head portion 1 1 a comprises a second combined bent 60 between the second radial bent 59 and the second connection point 51 . Beyond the second combined bent 60, the head portion 1 1 a extends in a skewed manner into the second orientation of the circumferential direction and into the axial direction towards the first face side 4.

[0094] Further, the head portion 1 1 a comprises a third radial bent 61 between the second combined bent 60 and the second connection point 51 . The third radial bent 61 is directed radially inwardly between the second combined bent 60 and the second connection point 51 .

[0095] Further, the head portion 1 1 a comprises a fourth radial bent 62 between the third radial bent 61 and the second connection point 51 . The fourth radial bent 62 is directed radially outwardly.

[0096] Further, the head portion 1 1 a comprises a third combined bent 63, beyond which the head portion 1 1 a extends at the circumferential position of the second connecting point 51 axially towards the second connecting point 51 . The third combined bent 63 is provided between the fourth radial bent 62 and the second connection point 51 .

[0097] Between the first combined bent 56 and the first radial bent 58, the head portion 1 1 a forms a first head portion section 64, which extends in the radial direction up to a first radial position. Between the turnaround bent 57 and the second combined bent 60, the head portion forms a second head portion section 65, which extends at the second axial position 54. Between the second radial bent 59 and the third radial bent 61 , the head portion 11 a forms a third head portion section 66, which extends at a second radial position being radially more outwardly than the first radial position. Between fourth radial bent 62 and the second connection point 51 , the head portion 1 1 a forms a fourth head portion section 67, which extends at a third radial position being radially more inwardly than the second radial position.

[0098] Fig. 10 is a top view of two second type segmented conductors 8c’, 8c”.

[0099] Circumferentially adjacent pairs of the second type segmented conductors 8c’, 8c” of different phase windings U, V, W are arranged such that the second head portion section 65 of one of the second type segmented conductors 8c’ of the pair extends partially along the third head portion 66 section of the other one of the second type segmented conductors 8c” of the pair.

[0100] Further, beyond its second combined bent 60, the head section 1 1 a of the other one of second type segmented conductors 8c” of the pair extends partially between the first head portion section 65 of the one of the second type segmented conductors 8c’ and the first axial face side 4. In particular, a section between the fourth radial bent 62 and the third combined bent 63 of the other one of the second type segmented conductors 8c” is covered by a section between the turnaround 57 and the first radial bent 58 of the one of the second type segmented conductors 8c’ as seen towards the first face side 4.

[0101] The stator 1 has been described afore with a design, in which the start leg portions 15, 16 are formed by l-type segmented conductors 5b, which allow connection of the partial windings 14a-d from the first face side 4. Nonetheless, according to a further embodiment, the segmented conductors are each realized by a U-type segmented conductor only. Therein the U-type segmented conductors forming the start leg portions 15 and end leg portions 16 are provided with a terminal portion 1 1 b at the second face side 5. In such an embodiment, the terminal device 17 (see Fig. 1 ) is arranged at the second face side so as to connect the partial windings 14a-d there.

[0102] According to alternative embodiments, the partial windings 14a-d are connected in series or in a combination of parallel and serial connection. Exemplarily, two partial windings 14a, b can be connected in series, two other partial windings 14c, d can be connected in series and the serial connections are connected in parallel.

[0103] Fig. 1 1 is a principle drawing of a vehicle 100 with an embodiment of an electric drive 101 .

[0104] The electric drive comprises an electric machine 102, a gearbox 103 mechanically coupled with the electric machine 102 and an inverter 104.

[0105] The electric machine 102 comprises a stator 1 according to any of the embodiments described before and a rotor 105 mounted rotatably with regard to the stator 1 . The electric machine 102 may be a synchronous motor. The rotor 105 may be permanently or electrically excited. Alternatively, the electric machine 102 may be an induction motor.

[0106] The inverter 104 is configured to supply an N-phase AC current to the stator 1 .

[0107] The electric vehicle 100 may be a battery-electric vehicle. Alternatively, the electric vehicle 100 comprises a further combustion engine (not shown) and is a hybrid vehicle.

Claims

Claims1 . Stator (1 ) for an electric machine (102), the stator (1 ) comprising a stator core (2), which has a longitudinal axis (3), an axial first face side (4) and an axial second face side (5) being opposite to the first face side (4) and which forms a plurality of slots (6) extending from the first face side (4) to the second face side (5), and a stator winding (7) having a number 2-P of poles and comprising a number N of phase windings (U, V, W), wherein N > 2; the stator winding (7) is formed by segmented conductors (8a-d, 8c’, 8c”), which form leg portions (9, 9’, 9”, 9a-f, 15, 16) each being arranged inside one of the slots (6) and connection portions (10a, 10b) each connecting two of the leg portions (9, 9’, 9”, 9a-f, 15, 16) at one of the face sides (4, 5) in an electrically conductive manner; the slots (6) are subdivided into first to L-th layers (20a-f), which are numbered according to their sequence in radial direction, wherein in each slot (6) one of the layers (20a-f) forms an accommodation position for one of the leg portions (9, 9’, 9”, 9a-f, 15, 16), the (2-i)-th and the (2-i— 1 )-th layers (20a-f) forming an i-th double layer (21 a-c) for all 1 < i < L / 2, wherein L > 4 is an even number;- for each pole and phase winding (U, V, W), the slots (6) form one winding zone (22, 22a, 22b) extending over all L layers (20a-f) and, in each layer (20a-f), over q slots (6) for containing L-q contiguous accommodation positions accommodating leg portions (9, 9’, 9”, 9a-f, 15, 16) of the same phase winding (U, V, W), wherein q > 2 is an integer; each phase winding (U, V, W) comprises first to A-th partial windings (14a- d), each partial winding (14a-d) forming a current path of a plurality of the leg portions (9, 9’, 9”, 9a-f, 15, 16) connected in series from a start leg portion (15) of the leg portions (9, 9’, 9”, 9a-f, 15, 16) to an end leg portion (16) of the leg portions (9, 9’, 9”, 9a-f, 15, 16), wherein A > q+1 and A + x-q, x being an integer;- for each phase winding (U, V, W), one of the winding zones (22, 22a, 22b) is a start winding zone (22a) and one of the winding zones (22, 22a, 22b) isan end winding zone (22b), exactly one winding zone (22, 22a, 22b) of each of the other phase windings (U, V, W) being arranged circumferentially between the start winding zone (22a) and the end winding zone (22b), wherein the start leg portions (15) of the partial windings (14a-d) of a respective one of the phase windings (U, V, W) are disposed in the start winding zone (15) and the end leg portions (16) of the partial windings (14a-d) of the respective one of the phase windings (U, V, W) are disposed in the end winding zone (22b).

2. Stator according to claim 1 , wherein the start leg portions (15) of q of the partial windings (14a-c) of the respective one of the phase windings (U, V, W) are arranged in the y-th double layer (21 a), wherein 1 < y < L / 2.

3. Stator according to claim 2, wherein y=1.

4. Stator according to claim 2 or 3, wherein the start leg portions (15) of the q of the partial winding (14a-c) are arranged in the same layer (20a) of the y-th double layer (21a).

5. Stator according to any of claims 2 to 4, wherein the end leg portions (16) of the q of the partial winding (14a-c) are arranged in the y-th double layer (21 a).

6. Stator according to any of claims 2 to 5, wherein the start leg portion (15) or the start leg portions (15) of (A-q) of the partial windings (14d) is or are arranged in the (y+1 )-th or (y-1 )-th double layer (21 b).

7. Stator according to claim 2 to 6, wherein the end leg portion (16) or the end leg portions (16) of the (A-q) of the partial windings (14d) is or are arranged in the y-th double layer (21 a).

8. Stator according to any of the preceding claims, wherein, in each partial winding (14a-d), the leg portions (9, 9’, 9”, 9a-f, 15, 16) are arranged in first to (2-P-q-L / A) ones of the accommodation positions defining a leg portion pattern of accommodation positions for the partial winding (14a-d), the numbering of the accommodation spaces corresponding to the sequence of the leg portions (9, 9’, 9”, 9a-f, 15, 16) along the current path and the start leg portion (15) being arranged in the first accommodation space.

9. Stator according to claim 8, wherein the leg portion pattern for the (j+1 )-th partial winding (14b-d) corresponds to the leg portion pattern of the first partial winding (14a) shifted by 2-N-q-j slots (6) in a predefined orientation of the circumferential direction for all 1 < j < A-1 , the first accommodation space of the (j+1 )-th partial winding (14b-d) being the (1 +2-j)-th accommodation space of the first partial winding (14a).

10. Stator according to any of the preceding claims, wherein the current path of the first partial winding (14a) comprises first to L-th subpaths (25a-f) numbered according to their sequence along the current path, the first subpath (25a) including the start leg portion (15); wherein each subpath (25a-f) includes first to (3-P / 2)-th ones of the leg portions (9a- f) being arranged in alternating layers (20a-f) of the same double layer (21 a- c).1 1 . Stator according to claim 10, wherein the leg portions (9a-f) of the k-th subpath (25a-c) are arranged in k-th double layer (21 a-c) for all 1 < k < L / 2 and the leg portions (9a-f) of the l-th subpath (25d-f) are arranged in the (L+1 -l)-th double layer (21 a-c) for all L / 2+1 < I < L.

12. Stator according to claim 10 or 1 1 , wherein the first to (L / 2)-th subpaths (25a-c) extend about the longitudinal axis (3) in a first orientation of the circumferential direction and the [(L / 2)+1 ]-th to L-thsubpaths (25d-f) extend about the longitudinal axis (3) in a second orientation of the circumferential direction, the second orientation being counteroriented with regard to the first orientation; and / or the first leg portion (9a) of the first subpath (25a) and the (3-P / 2)-th leg portion (9f) of the L-th subpath (25f) are arranged in the same layer (20-c); and / or the (3-P / 2)-th leg portion (9f) of the (L / 2)-th subpath (25c) and the first leg portion (9a) of the [(L / 2)+1 )]-th subpath (35d) are arranged in the same layer (20f).

13. Stator according to any of claims 10 to 12, wherein each winding zone (22, 22a, 22b) is subdivided into first to q-th subzones (26a-c), wherein the m-th subzone (26a-c) includes the m-th of first to q-th accommodation position of each layer (20a-f), the first to m-th accommodation positions being numbered according to their sequence in the circumferential direction, in particular according to the second orientation of the circumferential direction, wherein for all 1 < n < q the (2n)-th and the (2n-1 )-th leg portion (9a-f) of the first to (L / 2)-th subpaths (25a-c) are arranged in the n-th subzone (26a-c) and / or the (2n)-th and the (2n-1 )-th leg portions (9a-f) of the [(L / 2)+1 ] to L-th subpaths (25d-f) are arranged in the (q-n+1 )-th subzone (26a-c).

14. Stator according to any of the preceding claims, wherein the start leg portion (15) and the end leg portion (16) of each partial winding (14a-d) are realized by an l-type segmented conductor (8b) including the leg portion (9), a connection section (11 c) extending from the leg portion (9) out of the stator core (2) at the second face side (5) and a terminal portion (11 b) extending from the leg portion (9) out of the stator core (2) at the first face side (4), wherein segmented conductors (8a, c, d) forming the current path between the start leg portion (15) and the end leg portion (16) are each realized by an U-type segmented conductor (8a, c, d) including two leg portions (9’, 9”), a head portion (11 a) forming the connection portion (10a) thatconnects the two leg portions (9’, 9”) at the first face side (4) and, for each leg portion (9’, 9”), a connection section (1 1 c) extending from the leg portion (9’, 9”) out of the stator core (2) at the second face side (5) and being connected to the connection section (1 1 c) of another segmented conductor (8a-d) for forming the connection portion (1 Ob) that connects the leg portion(9, 9”) and one of the leg sections (9, 9’, 9”) of the other segmented conductor (8b); or the segmented conductors (8a) are each realized by an U-type segmented conductor (8a) including two leg portions (9’, 9”), a head portion (1 1 a) form- ing the connection portion (1 Oa) that connects the two leg portions at the first face side (4) and, for each leg portion (9’, 9”), a connection section (11 c) extending from the leg portion (9’, 9”) out of the stator core (2) at the second face side (5) for forming the connection portions (10b).

15. Electric machine for a vehicle, the electric machine comprising a stator according to any of the preceding claims and a rotor being mounted rotatably with regard to the stator.

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