Stator for an electric machine, and hairpin conductor therefor
Patent Information
- Application Number
- PCT/DE2026/100302
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-20
- Filing Date
- 2026-03-09
- Publication Date
- 2026-09-24
Smart Images
Figure DE2026100302_24092026_PF_FP_ABST
Abstract
Description
[0001] P241185 DE
[0002] - 1 -
[0003] Stator for an electric machine and hairpin-shaped conductor for this purpose
[0004] The present invention relates firstly to a hairpin-shaped conductor for a winding of a stator of an electric machine. The hairpin-shaped conductor enables high currents and high packing density in the electric machine. The invention further relates to a stator for an electric machine.
[0005] It is known from the prior art to design the conductors for a winding in the stator of an electric motor as hairpin-shaped. Fig. 5 shows two such hairpin-shaped conductors. The hairpin-shaped conductors are designed to be arranged layer by layer in slots of the stator, with a first leg 11 and a second leg 12 of each hairpin-shaped conductor lying in the slots and connected to each other via a crown section 13 of the respective hairpin-shaped conductor. A first angled section 14 extends from the first leg 11 to the crown section 13. A second angled section 15 extends from the crown section 13 to the second leg 12. The first angled section 14 and the second angled section 15 are connected to each other in the crown section 13. The design of the crown sections 13 of the hairpin-shaped conductors determines the height WKH of a winding head of the winding.The height of the winding head (WKH) affects the integration of the electric motor, its performance, and its cost. Therefore, the aim is to make the winding head as small as possible. This allows for a reduction in the installation space required for the electric motor and the winding length, thereby increasing efficiency by reducing ohmic resistance, lowering manufacturing costs, and saving copper for the conductors.
[0006] Design measures to reduce the height of the winding head (WKH) are known from the prior art. For example, a bending angle α is increased. This modification is possible provided that a wire width (DB) or a diagonal distance (LD) is reduced. Since a reduction (P241185 DE)
[0007] - 2 -
[0008] Since reducing the wire width DB is usually not possible, only the diagonal spacing LD can be reduced. However, care must be taken to ensure that there is no collision between adjacent conductors in the area of the apex section 13, also known as the split.
[0009] Fig. 6 shows a detail of the hairpin-shaped conductor shown in Fig. 5. The distance LS between the apex sections 13 of the hairpin-shaped conductor is a parameter that limits the reduction in the height WKH of the winding head. The bending radius RS of the apex sections 13 can also be increased to reduce the height WKH of the winding head. However, this reduces the distance LS, which is also not desirable.
[0010] Fig. 7 shows one of the hairpin-shaped ladders shown in Fig. 5 in a top view. The curvature of the ladder can be described in terms of a first curvature direction k1 and a second curvature direction k2 with respect to a path length of the extension of the respective hairpin-shaped ladder. This path length represents an arc length. The first curvature direction k1 is defined perpendicular to a plane in which the first leg 11 and the first angle segment 14 lie. The second curvature direction k2 is defined perpendicular to the first curvature direction k1 and perpendicular to the first leg 11.
[0011] DE 102020216 151 A1 describes an electrical machine with a stator comprising a stator core with a plurality of slots subdivided into at least layers. Shaped conductors, which can be configured as hairpin conductors, are arranged in the slots. Figure 1 of DE 102020216 151 A1 shows the hairpin conductors. The curvature of these hairpin conductors in the first curvature direction k1 and the second curvature direction k2 described above, with respect to a path length of the extension of the respective hairpin conductor, is shown in a diagram in Figure 8 included here. The x-axis represents the path length I, which can also be considered the arc length with respect to the curvature and can be measured, for example, in mm. The y-axis represents the respective curvature k1, k2, which can be measured, for example, in 1 / mm. P241185 DE
[0012] - 3 -
[0013] DE 102019 122550 A1 discloses an electric machine with a hairpin-shaped winding. The electric machine comprises a stator core which defines slots and hairpins. The hairpins are arranged in the slots and selectively connected at junctions to form windings. A U-shaped bridge has spaced-apart legs which are connected to each other by a U-section. The legs are attached at one point radially outside the slots on a pair of hairpins, such that the U-section faces the core. Figure 4 of DE 102019 122550 A1 shows one of the hairpins. The progression of the curvatures of this hairpin in the first curvature direction k1 and in the second curvature direction k2 described above, with respect to a path length of the extension of the respective hairpin, is shown in a diagram in Figure 9, which is included here.The x-axis represents the path length I, which can also be considered the arc length in relation to the curvature and can be measured, for example, in mm. The y-axis represents the respective curvature k1, k2, which can be measured, for example, in 1 / mm.
[0014] German patent DE 102019105583 A1 discloses an electric machine with a hairpin-shaped winding and staggered hairpin connections. The electric machine comprises a stator core that defines slots. Hairpins are arranged in the slots and selectively joined at connections to form windings in at least two radial layers. Figure 2 of DE 102019105583 A1 shows the hairpins. The curvature of these hairpins in the first curvature direction k1 and the second curvature direction k2 described above, with respect to a path length of the extension of the respective hairpin, is shown in a diagram in Figure 10, which is included here. The path length I, which can also be considered the arc length with respect to the curvature and can be measured, for example, in mm, is plotted on the x-axis. The y-axis shows the respective curvature k1, k2, which can be measured, for example, in 1 / mm. P241185 DE
[0015] - 4 -
[0016] From CN 117118111 A, a stator structure is known which comprises a stator core provided with a plurality of stator slots distributed at intervals around the circumference of the stator core. A stator winding comprises a plurality of hairpin-shaped conductor bars. The hairpin-shaped conductor bars are inserted into the stator slots. Two pins of each hairpin-shaped conductor bar are twisted and extend from the inside to the outside of the stator slot. The plurality of hairpin-shaped conductor bars spans all stator slots with the same slot number. Two pins of each hairpin-shaped conductor bar are arranged in the (2n-1)th and (2n)th layers.
[0017] US Patent 2022 / 0140683 A1 discloses an electric motor comprising an iron core and a multiphase winding structure. The iron core is provided with a plurality of circumferentially arranged slots. One side of the iron core is a plug-in side and the other side is a weld side. The multiphase winding structure is arranged in the plurality of slots of the iron core. Each phase of the winding structure comprises N parallel winding sub-windings formed by a plurality of hairpin conductors of different shapes. The variable N is a positive even number. The conductors forming each phase of the winding structure are arranged in the same sub-winding on a non-adjacent conductor layer corresponding to the slots. Fig. 6b of the
[0018] US 2022 / 0140683 A1 shows a hairpin conductor with a projection for a serial connection at a distance of 5 (y-1). The curvature of this hairpin conductor in the first curvature direction k1 and the second curvature direction k2 described above, with respect to a path length of the hairpin conductor's extension, is shown in a diagram in Fig. 11, included here. The x-axis represents the path length I, which can also be considered the arc length with respect to the curvature and can be measured, for example, in mm. The y-axis represents the respective curvature k1, k2, which can be measured, for example, in 1 / mm. The curvature in the first curvature direction k1 is characterized by the fact that it does not drop directly from a positive value to a negative value, but rather has a plateau in between where this curvature is zero. P241185 DE
[0019] - 5 -
[0020] Starting from the prior art, the object of the present invention is to reduce the height WKH of a winding head of a winding of a stator of an electrical machine formed from a plurality of hairpin conductors, without having to reduce the distance LS of the hairpin conductors in the region of their apex.
[0021] The aforementioned problem is solved by a hairpin-shaped conductor according to the attached claim 1 and by a stator according to the attached dependent claim 9.
[0022] The hairpin-shaped conductor according to the invention is designed to form a winding. The winding is intended to form a coil in an electric machine in order to convert an electric current into a magnetic field or vice versa. The winding preferably forms a component of a stator of an electric motor. The electric motor is preferably a drive motor of a motor vehicle. The electrical hairpin-shaped conductor is preferably made of copper or another metal with high electrical conductivity. The conductor has a cross-sectional area that is preferably at least 2 mm². 2 amounts.
[0023] The hairpin-shaped conductor comprises a first leg, which is preferably straight or only very slightly curved, so that it can be considered straight. The hairpin-shaped conductor also comprises a second leg, which is preferably straight or only very slightly curved, so that it can be considered straight. The first leg and the second leg are preferably arranged parallel to each other. The hairpin-shaped conductor further comprises a vertex section, which can also be referred to as a bend. In addition, the hairpin-shaped conductor comprises a first angular section extending from the first leg to the vertex section and a second angular section extending from the vertex section to the second leg. The first angular section and the second angular section are preferably each straight or only slightly curved, so that they can each be considered straight.
[0024] - 6 -
[0025] The first and second angled sections are connected at the vertex. Thus, the hairpin-shaped conductor forms a continuous electrical conductor from the first leg, through the first angled section, across the vertex, across the second angled section, to the second leg. In this respect, the hairpin shape of the conductor can also be viewed as an inverted square U-shape, where the legs of the conductor form the legs of the U-shape, and the vertex with the angled sections connects the legs of the U-shape. The vertex with the two angled sections has the shape of a roof.
[0026] The first leg and the first angular segment lie in a plane of extension of the conductor. The second leg is preferably arranged parallel to the plane of extension by a comparatively small offset, so that the second leg also lies approximately in the plane of extension, which also applies to the second angular segment. In the following, reference is made to two directions of curvature to describe the path of the conductor in space. A first direction of curvature k1 is defined perpendicular to the plane of extension. A second direction of curvature k2 is defined perpendicular to the first direction of curvature k1 and perpendicular to the first leg. The first direction of curvature k1 is aligned with a wire thickness of the hairpin-shaped conductor, while the second direction of curvature k2 is aligned with a wire width of the hairpin-shaped conductor.
[0027] According to the invention, the conductor has a curvature profile in the first curvature direction k1 over a path length of its extension, which in the apex section rises from a first base dimension to a first positive dimension, then immediately falls from the first positive dimension to a first negative dimension, and then rises from the first negative dimension to a second base dimension. An important difference from the prior art is that no relevant path length is formed between the part of the conductor exhibiting the first positive dimension of this curvature and the part of the conductor exhibiting the first negative dimension of this curvature. In contrast, in a conductor known from the prior art, a path length is formed between these parts of the conductor, in which the P241185 DE
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[0029] The curvature is zero, meaning there is a plateau in the curvature profile in the first direction. The basic measures are characterized by being very small in magnitude and preferably equal to zero.
[0030] According to the invention, the conductor also has a special profile in the second direction of curvature k2. The conductor has a profile of its curvature in the second direction of curvature k2 over the path length of its extension, which rises to a second positive dimension in the transition from the first leg to the first angular segment and then falls from the second positive dimension to a third base dimension, then falls from the third base dimension to a second negative dimension in the vertex segment, then rises from the second negative dimension to a third positive dimension, then falls from the third positive dimension to a third negative dimension and then rises from the third negative dimension to a fourth base dimension, and then rises from the fourth base dimension to a fourth positive dimension in the transition from the second angular segment to the second leg and then falls from the fourth positive dimension.The basic measures are characterized by being very small in magnitude and preferably equal to zero.
[0031] The given positive dimensions become negative dimensions and at the same time the given negative dimensions become positive dimensions if reversed orientations are chosen for the curvature directions k1, k2.
[0032] A particular advantage of the hairpin-shaped conductor according to the invention is that the spacing LS between several of the hairpin-shaped conductors in their apex sections within the winding can be increased without having to increase the bending radius RS. This is possible according to the invention because the described curvature pattern results in the apex section being offset upwards, further away from the leg, while maintaining an unchanged radius RS and an unchanged bending angle α.
[0033] In preferred embodiments, the hairpin-shaped conductor exhibits rotational symmetry. An axis of rotation is arranged parallel to the two legs and intersects a midpoint of the apex section. A rotation of the P241185 DE
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[0035] The hairpin-shaped conductor rotated 180° around this axis of rotation forms the hairpin-shaped conductor in itself.
[0036] In preferred embodiments, the curvature in the second curvature direction k2 increases along the path length of the conductor at the transition from the first leg to the first angular segment from a fifth base dimension to the second positive dimension. At the transition from the second angular segment to the second leg, this curvature preferably decreases from the fourth positive dimension to a sixth base dimension. The base dimensions are characterized by being very small in magnitude and preferably equal to zero.
[0037] In preferred embodiments, the absolute magnitude of the first base measure and the absolute magnitude of the second base measure are each at least 5 times smaller than the absolute magnitude of the first positive measure and each at least 5 times smaller than the absolute magnitude of the first negative measure. The absolute magnitude of the first base measure and the absolute magnitude of the second base measure are preferably equal. The first base measure and the second base measure are preferably equal to zero.
[0038] In preferred embodiments, the absolute magnitude of the third base measure and the absolute magnitude of the fourth base measure are each at least 5 times smaller than the absolute magnitude of the second positive measure, each at least 5 times smaller than the absolute magnitude of the second negative measure, each at least 5 times smaller than the absolute magnitude of the third positive measure, each at least 5 times smaller than the absolute magnitude of the third negative measure, and each at least 5 times smaller than the absolute magnitude of the fourth positive measure. The absolute magnitude of the third base measure and the absolute magnitude of the fourth base measure are preferably equal. The third base measure and the fourth base measure are preferably equal to zero.
[0039] In preferred embodiments, the absolute value of the fifth base measure and the absolute value of the sixth base measure are each at least 5 times smaller than the absolute value of the second positive measure, each at least 5 times smaller than the absolute value of the second negative measure, P241185 DE
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[0041] The absolute value of the third positive measure must be at least five times smaller than the absolute value of the third negative measure, and at least five times smaller than the absolute value of the fourth positive measure. The absolute value of the fifth base measure and the absolute value of the sixth base measure are preferably equal. The fifth base measure and the sixth base measure are preferably equal to zero.
[0042] The increase and decrease from the base measures to the positive measures or to the negative measures, as well as between the positive measures and the negative measures and vice versa, preferably occur linearly with a large first derivative with respect to the path, i.e. with a large slope or with a large gradient.
[0043] However, the ascent and descent can also exhibit other characteristics. For example, the ascent and descent can also be non-linear, with a less steep gradient or slope.
[0044] In preferred embodiments, the first positive dimension has an absolute value that differs by at most 20% from the absolute value of the first negative dimension. More preferably, the first positive dimension and the first negative dimension have the same absolute value. This results in symmetrical curvatures in the vertex section.
[0045] In preferred embodiments, the path length of the conductor along its curvature in the first direction of curvature k1, from the point where it rises from the first base dimension to the first positive dimension and then drops from the first positive dimension directly to the first negative dimension, defines a first vertex segment of the vertex segment. Similarly, the path length of the conductor along its curvature in the first direction of curvature k1, from the point where it drops from the first positive dimension directly to the first negative dimension and then rises from the first negative dimension to the second base dimension, defines a second vertex segment of the vertex segment. In preferred embodiments, the length of the first vertex segment differs by at most 20% from the length of the second vertex segment. The first vertex segment and the second vertex segment are P241185 DE
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[0047] furthermore, preferably of the same length. This leads to symmetrical curvatures in the vertex section.
[0048] In preferred embodiments, the second positive dimension differs from the fourth positive dimension by at most 20%. In further preferred embodiments, the second and fourth positive dimensions are equal in order to contribute to a symmetrical formation of the hairpin-shaped conductor in this respect as well.
[0049] In preferred embodiments, the path length of the conductor's extension over the course of its curvature in the second curvature direction k2 from the rise to the second positive dimension to the fall from the second positive dimension to the third base dimension defines a first curvature section.
[0050] Accordingly, the path length of the conductor along its curvature in the second curvature direction k2, from the point where it rises from the fourth base dimension to the fourth positive dimension until it falls from the fourth positive dimension, defines a second curvature segment. In preferred embodiments, the first curvature segment has a length that differs from the length of the second curvature segment by at most 20%. The first and second curvature segments are preferably of equal length. The transitions from the legs to the angled sections are also identical in this respect.
[0051] In preferred embodiments, the second negative dimension differs from the third negative dimension by at most 20%. In further preferred embodiments, the second and third negative dimensions are equal. This results in a symmetrical shape in the apex section.
[0052] In preferred embodiments, the path length of the conductor's extension along its curvature in the second curvature direction k2, from the point where it drops from the third base dimension to the second negative dimension to the point where it rises from the second negative dimension to the third positive dimension, defines a first crest curvature segment. Accordingly, the path length of the extension P241185 DE defines
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[0054] The conductor, along its curvature in the second direction k2, from the point where it drops from the third positive dimension to the third negative dimension and then rises from the third negative dimension to the fourth base dimension, has a second apex curvature section. In preferred embodiments, the first apex curvature section has a length that differs by at most 20% from the length of the second apex curvature section. The first and second apex curvature sections are preferably of equal length. This also contributes to the symmetrical design of the apex section.
[0055] In preferred embodiments, the first and second vertex curvature sections are spaced apart from the center point of the vertex section. The first and second vertex curvature sections are preferably arranged symmetrically with respect to the center point of the vertex section. The spacing of the two vertex curvature sections results in the third positive dimension being formed over a length of the conductor. The symmetry of the two vertex curvature sections results in the third positive dimension being formed centrally within the vertex section, specifically in a central vertex region in which the first and second vertex sub-sections are preferably arranged without spacing and symmetrically with respect to the center point of the vertex section.
[0056] The stator according to the invention forms a component of an electric machine, which preferably also includes a rotor rotatable relative to the stator. The stator comprises a winding formed by a plurality of hairpin-shaped conductors. The winding is preferably formed by a plurality of the described preferred embodiments of the hairpin-shaped conductor. The stator has a plurality of slots arranged continuously within the stator, in each of which several legs of the hairpin-shaped conductors are arranged in layers. The number of layers is preferably between four and ten. The stator preferably also has features described in connection with the conductor according to the invention. P241185 DE
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[0058] In preferred embodiments, each hairpin-shaped conductor has its first leg in an nth layer in one of the slots, while its second leg is in an mth layer in another slot. The variables n and m represent natural numbers determined by counting the layers arranged one above the other in the slots. The layers are counted identically in all slots. The layers are arranged radially. Preferably, the radially innermost layer forms the first layer, with the layers being counted radially outwards. The difference between m and n is preferably zero or one. Thus, the first leg and the second leg of each hairpin-shaped conductor are located in the same layer or in two layers that are immediately adjacent in the radial direction.Preferred combinations of the variables m and n are: 1-2, 2-1, 3-4, 4-3, 5-6, 6-5, 7-8, 8-7, etc. for the regularly arranged hairpin ladders, as well as 3-2, 2-3, 5-4, 4-5, 7-6, 6-7, etc. for the hairpin ladders with a change of position, as well as 2-2, 4-4, 6-6, 8-8, etc. for the hairpin ladders with an outside reversal, and 1-1 for the hairpin ladders with an inside reversal.
[0059] Further advantages, details, and developments of the invention will become apparent from the following description of preferred embodiments in comparison to the prior art, with reference to the drawing. The drawing shows:
[0060] Fig. 1 : a preferred embodiment of a hairpin-shaped conductor according to the invention in a view from the front;
[0061] Fig. 2: the ladder shown in Fig. 1 in a top view;
[0062] Fig. 3: the ladder shown in Fig. 1 in a perspective view;
[0063] Fig. 4: a diagram illustrating the path lengths of the conductor shown in Fig. 1 in two directions of curvature; P241185 DE
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[0065] Fig. 5: two hairpin-shaped ladders according to the prior art in a front view;
[0066] Fig. 6: a detail of the ladder shown in Fig. 5;
[0067] Fig. 7: one of the hairpin-shaped ladders shown in Fig. 5 in a top view;
[0068] Fig. 8: a diagram illustrating path lengths of a hairpin-shaped conductor according to a first prior art in two directions of curvature;
[0069] Fig. 9: a diagram illustrating path lengths of a hairpin-shaped conductor according to a second prior art in two directions of curvature;
[0070] Fig. 10: a diagram illustrating path lengths of a hairpin-shaped conductor according to a third prior art in two directions of curvature;
[0071] Fig. 11: a diagram illustrating path lengths of a hairpin-shaped conductor according to a fourth prior art in two directions of curvature;
[0072] Fig. 12: a group of the hairpin-shaped ladders shown in Fig. 1 compared to a group of hairpin-shaped ladders according to the prior art;
[0073] Fig. 13: Details of the groups of hairpin-shaped ladders shown in Fig. 12;
[0074] and
[0075] Fig. 14: Several of the hairpin-shaped ladders shown in Fig. 1 in a groove of a
[0076] Stators.P241185 DE
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[0078] Fig. 1 shows a preferred embodiment of a hairpin-shaped conductor according to the invention in a frontal view. The hairpin-shaped conductor is designed to be arranged layer by layer in slots 47 (shown in Fig. 14) of a stator 28 (shown in Fig. 14) of an electric motor to form a winding in the stator 28 (shown in Fig. 14). The hairpin-shaped conductor comprises a first leg 11 and a second leg 12, which are straight in this illustration but can also be slightly curved. The hairpin-shaped conductor also comprises a top section 13, which can also be referred to as a wrap. The hairpin-shaped conductor further comprises a first angular section 14 extending from the first leg 11 to the top section 13 and a second angular section 15 extending from the top section 13 to the second leg 12.The first angle segment 14 and the second angle segment 15 are preferably straight and angled relative to the first leg 11 and the second leg 12, respectively. The first angle segment 14 and the second angle segment 15 are connected to each other at the vertex segment 13.
[0079] The apex section 13 has a first apex subsection 31 and a second apex subsection 32, in which the conductor has certain curvatures, which are explained in more detail with reference to Fig. 4. The first apex subsection 31 and the second apex subsection 32 are of equal length and rotationally symmetrical.
[0080] The transition from the first leg 11 to the first angular section 14 is formed in a first curvature section 35, in which the conductor has a specific curvature, which is explained in more detail with reference to Fig. 4. The transition from the second angular section 15 to the second leg 12 is formed in a second curvature section 36, in which the conductor has a specific curvature, which is explained in more detail with reference to Fig. 4. The first curvature section 35 and the second curvature section 36 are of equal length and rotationally symmetrical. P241185 DE
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[0082] According to the invention, the apex section 13 has a first apex curvature section 41 and a second apex curvature section 42, in which the conductor has certain curvatures, which are explained in more detail with reference to Fig. 4. The first apex curvature section 41 and the second apex curvature section 42 are of the same length and rotationally symmetrical.
[0083] Fig. 2 shows the ladder shown in Fig. 1 in a top view. In this view, the curves in the first vertex section 31 and in the second vertex section 32 are particularly visible.
[0084] The curvature of the hairpin-shaped conductor is described with reference to Fig. 4, specifically regarding a first curvature direction k1 and a second curvature direction k2. The first curvature direction k1 is perpendicular to a plane in which the first leg 11 and the first angled segment 14 lie. The second curvature direction k2 is perpendicular to the first curvature direction k1 and perpendicular to the first leg 11.
[0085] Fig. 3 shows the ladder shown in Fig. 1 in a perspective view. In this view, the curvatures in the first vertex curvature section 41 and in the second vertex curvature section 42 are particularly visible.
[0086] Fig. 4 shows a diagram illustrating the path lengths of the hairpin-shaped conductor shown in Fig. 1 in the two directions of curvature k1 and k2. The x-axis represents the path length I, which can also be considered the arc length with respect to the curvature and can be measured, for example, in mm. The y-axis represents the respective curvature k1, k2, which can be measured, for example, in 1 / mm.
[0087] The curvature in the first curvature direction k1 is zero in the first leg 11 (shown in Fig. 1) and in the first angular segment 14 (shown in Fig. 1). In the first P241185 DE
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[0089] In vertex segment 31 (shown in Fig. 1), this curvature increases from zero to a first positive value 21 and remains constant in vertex segment 31 (shown in Fig. 1). In the transition from the first vertex segment 31 (shown in Fig. 1) to the second vertex segment 32 (shown in Fig. 1), the curvature drops directly from the first positive value 21 to a first negative value 22 and remains constant in the second vertex segment 32 (shown in Fig. 1). At the end of the second vertex segment 32 (shown in Fig. 1), the curvature increases from the first negative value 22 to zero. In the second angle segment 15 (shown in Fig. 1) and in the second leg 12 (shown in Fig. 1), this curvature remains zero. The first positive measure 21 and the first negative measure 22 have the same absolute value.
[0090] The curvature in the second curvature direction k2 is zero in the first leg 11 (shown in Fig. 1). In the first curvature section 35 (shown in Fig. 1), this curvature increases to a second positive value 24 and remains constant in the first curvature section 35 (shown in Fig. 1). At the end of the first curvature section 35 (shown in Fig. 1), this curvature decreases from the second positive value 24 back to zero. In the first vertex curvature section 41 (shown in Fig. 1), this curvature decreases from zero to a second negative value 26 and remains constant until the end of the first vertex curvature section 41 (shown in Fig. 1), whereupon it immediately increases to a third positive value 27. In a central region of the vertex section 13 (shown in Fig. 1), this curvature constantly exhibits the third positive dimension 27. At the beginning of the second vertex curvature section 42 (shown in Fig.1) This curvature drops directly from the third positive dimension 27 to a third negative dimension 28 and remains constant until the end of the second vertex curvature section 42 (shown in Fig. 1), whereupon it immediately rises to zero. The second negative dimension 26 and the third negative dimension 28 are equal. In the second curvature section 36 (shown in Fig. 1), this curvature rises to a fourth positive dimension 30 and remains constant in the second curvature section 36 (shown in Fig. 1). At the end of the second curvature section 36 (shown in Fig. 1), this curvature drops again from the fourth positive dimension 30 to zero. The second positive dimension 24 and the fourth positive dimension 30 are equal. P241185 DE.
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[0092] Figures 5 to 11 show the state of the art and were described in the introductory assessment of the state of the art.
[0093] Fig. 12 shows a group 44 of the hairpin-shaped ladders shown in Fig. 1 compared to a group 45 of hairpin-shaped ladders according to the prior art. It can be seen that the hairpin-shaped ladders of group 44 according to the invention can be made with a lower height than the hairpin-shaped ladders of group 45 according to the prior art, without reducing the spacing between them in the apex sections 13. The winding head height WKH (shown in Fig. 5) is about 2 mm to 4 mm lower.
[0094] Fig. 13 shows details of the groups 44, 45 of hairpin-shaped ladders shown in Fig. 12 in the area of the apex sections 13. It can be seen that the hairpin-shaped ladders of group 44 according to the invention have a sufficient distance LS (shown in Fig. 6) in the apex sections 13.
[0095] Fig. 14 shows several of the hairpin-shaped conductors shown in Fig. 1 in a slot 47 of a stator 48 of an electric motor (not shown) in a cross-sectional view. The stator 48 has a plurality of slots 47, which are arranged uniformly around the stator 48 and in which several of the hairpin-shaped conductors are arranged in the same manner. In each slot 47, the first leg 11 or the second leg 12 of the respective hairpin-shaped conductor is arranged. The legs 11, 12 of the hairpin-shaped conductors are arranged in four layers in the slots 47. The legs 11, 12 of each hairpin-shaped conductor are arranged either in a first layer and in a second layer or in a third layer and in a fourth layer of the four layers. P241185 DE
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[0097] List of reference signs
[0098] 11 first thigh
[0099] 12 second thigh
[0100] 13 Vertex section
[0101] 14 first angle segment
[0102] 15 second angle segment
[0103] 16
[0104] 17
[0105] 18
[0106] 19
[0107] 20
[0108] 21 first positive measure
[0109] 22 first negative measure
[0110] 23
[0111] 24 second positive measure
[0112] 25
[0113] 26 second negative measure
[0114] 27 third positive measure
[0115] 28 third negative measure
[0116] 29
[0117] 30 fourth positive measure
[0118] 31 first vertex section
[0119] 32 second vertex section
[0120] 33
[0121] 34
[0122] 35 first curvature section P241185 DE
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[0124] 36 second curvature section
[0125] 37
[0126] 38
[0127] 39
[0128] 40
[0129] 41 First vertex curvature section 42 Second vertex curvature section 43
[0130] 44 Group of hairpin-shaped ladders 45 Group of hairpin-shaped ladders 46
[0131] 47 Nut
[0132] 48 Stator
Claims
P241185 DE - 20 - Patent claims 1. Hairpin-shaped conductor for a winding of a stator (48) of an electrical machine; comprising a first leg (11), a second leg (12), a vertex section (13), a first angular section (14) extending from the first leg (11) to the vertex section (13), and a second angular section (15) extending from the vertex section (13) to the second leg (12); wherein the first angular section (14) and the second angular section (15) are connected to each other in the vertex section (13); wherein the first leg (11) and the first angular section (14) lie in a plane of extension, wherein a first direction of curvature (k1) is defined perpendicular to the plane of extension; wherein a second direction of curvature (k2) is defined perpendicular to the first direction of curvature (k1) and perpendicular to the first leg (11);wherein the hairpin-shaped ladder has a curvature in the first direction of curvature (k1) over a path length of its extension, which in the vertex section (13) rises from a first base measure to a first positive measure (21), falls immediately from the first positive measure (21) to a first negative measure (22) and rises from the first negative measure (22) to a second base measure;and wherein the hairpin-shaped ladder has a curvature in the second direction of curvature (k2) over the path length of its extension, which rises to a second positive dimension (24) in the transition from the first leg (11) to the first angular segment (14) and falls from the second positive dimension (24) to a third base dimension, falls from the third base dimension to a second negative dimension (26) in the vertex segment (13), rises from the second negative dimension (26) to a third positive dimension (27), falls from the third positive dimension (27) to a third negative dimension (28) and rises from the third negative dimension (28) to a fourth base dimension, and rises from the fourth base dimension to a fourth positive dimension (30) in the transition from the second angular segment (15) to the second leg (12) falls.P241185 DE; - 21 - 2. Hairpin-shaped conductor according to claim 1, characterized in that the first positive dimension (21) has an absolute value which differs by no more than 20% from an absolute value of the first negative dimension (22).
3. Hairpin-shaped conductor according to claim 1 or 2, characterized in that the path length of the extension of the conductor over the course of its curvature in the first direction of curvature (k1) from the rise from the first base dimension to the first positive dimension (21) to the fall from the first positive dimension (21) directly to the first negative dimension (22) defines a first vertex subsection (31) of the vertex section (13), and that the path length of the extension of the conductor over the course of its curvature in the first direction of curvature (k1) from the fall from the first positive dimension (21) directly to the first negative dimension (22) to the rise from the first negative dimension (22) to the second base dimension defines a second vertex subsection (32) of the vertex section (13); wherein the first vertex segment (31) has a length which differs by no more than 20% from the length of the second vertex segment (32).
4. Hairpin-shaped conductor according to one of claims 1 to 3, characterized in that the second positive dimension (24) differs from the fourth positive dimension (30) by a maximum of 20%.
5. Hairpin-shaped conductor according to one of claims 1 to 4, characterized in that the path length of the conductor's extension along its curvature in the second direction of curvature (k2) from the rise to the second positive dimension (24) to the fall from the second positive dimension (24) to the third base dimension defines a first curvature section (35), and that the path length of the conductor's extension along its curvature in the second direction of curvature (k2) from the rise from the fourth base dimension to the fourth positive dimension (30) to the fall from the fourth positive dimension (30) defines a second curvature section (36); wherein the first curvature section (35)P241185 DE - 22 - a length which differs by no more than 20% from the length of the second curvature section (36).
6. Hairpin-shaped conductor according to one of claims 1 to 5, characterized in that the second negative dimension (26) differs from the third negative dimension (28) by a maximum of 20%.
7. Hairpin-shaped conductor according to any one of claims 1 to 6, characterized in that the path length of the conductor's extension along its curvature in the second direction of curvature (k2) from the drop from the third base dimension to the second negative dimension (26) to the rise from the second negative dimension (26) to the third positive dimension (27) defines a first vertex curvature section (41), and that the path length of the conductor's extension along its curvature in the second direction of curvature (k2) from the drop from the third positive dimension (27) to the third negative dimension (28) to the rise from the third negative dimension (28) to the fourth base dimension defines a second vertex curvature section (42); wherein the first vertex curvature section (41) has a length which differs by at most 20% from the length of the second vertex curvature section (42).
8. Hairpin-shaped conductor according to claim 7, characterized in that the first vertex curvature section (41) and the second vertex curvature section (42) are spaced apart and arranged symmetrically with respect to a center point of the vertex section (13).
9. Stator (48) for an electric machine; comprising a winding with a plurality of hairpin-shaped conductors according to one of claims 1 to 8, wherein the stator (48) has a plurality of slots (47) which are arranged circumferentially distributed in the stator (48) and in which several of the legs (11, 12) of the hairpin-shaped conductors are arranged in layers.
10. Stator (48) according to claim 9, characterized in that the individual hairpin-shaped conductors are each connected with their first leg (11) in an n-th P241185 DE - 23 - layer in one of the grooves (47) and with their second leg (12) in an m-th layer in another of the grooves (47), where the difference between m and n is zero or one.