Winding with covering pin

Abstract

The invention relates to a winding (1) for a power component having a hairpin (300) and a cover pin (600), said winding extending over an outer layer (La), an inner layer (Li) and a plurality of intermediate layers (Lm), forming a cylindrical circumferential surface of the winding (1). According to the invention, the hairpin sections (300) are arranged in the intermediate layer (Lm), at least one hairpin section (300) being provided for each coil strand, the distance between the two conductor elements of which corresponds to a larger pitch width that differs from the standard pitch width. The intermediate layer (Lm) is spanned by a covering pin (600), the two conductor elements of which are arranged on the one hand in the outer layer (La) and on the other hand in the inner layer (Li).

Description

TECHNICAL FIELD

[0001] The invention relates to a winding with hairpin portions and covering pins for an electrical machine part, such as a stator or a rotor, and to an electrically driven axle drive and to a motor vehicle. BACKGROUND

[0002] A winding with hairpin portions, also referred to as hairpin winding, is a winding composed of a plurality of coils, which are each formed by at least one coil strand, which in turn is composed of a plurality of hairpin portions that are electrically connected to one another. A hairpin portion is a profiled wire with a generally rectangular cross section, having two side-by-side conductor elements that exhibit a U shape, which are integrally connected to one another by means of a turn region, also referred to as winding head, and have two end portions on the same side. The end portions of the hairpin portions are electrically conductively connected to one another, so that the hairpin portions form a winding strand in a series connection. One or a plurality of parallel-connected winding strands form a coil. A winding, for example of a stator of a two-pole electrical machine, comprises three coils, which are each assigned to one phase of an electrical network. The end portions of a winding strand are formed by the free end portions of the hairpin portions at the boundaries of the respective winding strand and are referred to as connecting pins. For winding strands in a laminated core of a ring stator, the hairpin portions are located in grooves that run parallel to one another and axially and form a plurality of winding layers. A winding layer here comprises at least one radially outer layer and a radially inner layer and a plurality of intermediate layers.

[0003] Each groove is assigned a defined position in the laminated core along the circumference of the laminated core and can accommodate a plurality of conductor elements of hairpin portions, which here are arranged radially adjacent in the groove. The number of hairpin portions arranged in a groove essentially corresponds to the number of winding layers. The interconnection of the hairpin portions to one another and to the individual phases and the arrangement of the hairpin portions in a particular groove and a particular layer characterizes the winding pattern of the winding and thus the winding.

[0004] Various different embodiments of windings are known, which are each designed advantageously for the particular requirements of an electrical machine. These requirements are generally good synchronism, low operating noise, avoidance of circulating currents and high harmonics of the electrical machine, and as uniform as possible mutual inductance of parallel winding strands, so that as uniform as possible, rotating and superimposed magnetic fields result.

[0005] For the purpose of describing the winding, the side at which the hairpin portions are interconnected with each other is referred to as the lay side. The opposite side, at which the winding heads are located, is referred to as the transition region side. In order to meet the above requirements, hairpin portions of different coil widths can be used in the winding, for example. The coil width of a hairpin portion is determined by the pitch of the two grooves in which the two conductor elements of the hairpin portion are located, and by the length of the grooves, which is equal. Different coil widths of the hairpin portions result in different maximum winding head heights by spanning different numbers of grooves, which results in different pitches. The pitch is referred to as the pitch width and is obtained by adding one to the number of grooves spanned. The winding heads of the usual hairpin portions are approximately formed by isosceles triangles, the equal-length legs of which are at equal angles to each other, regardless of the size of the pitch width, which results in different maximum winding head heights.

[0006] If the number of grooves of the winding is greater than one, hairpin portions are used in the coil which have a coil width, also referred to as a pitch width, which is different from the standard coil width, also referred to as the standard pitch width. For example, the number of grooves can be three, which means that two or three parallel coil strands are used for connection to the same pole, and these coil strands are guided in three directly adjacent grooves. A number of grooves greater than one reduces operating noise and losses, for example, by reducing higher harmonics of the electric machine in which the stator is arranged. Changing the winding direction of the coil strands and / or exchanging the arrangement of the coil strands achieves a further reduction in losses, which requires the use of hairpin portions having a coil width which is different from the standard coil width.

[0007] A winding having hairpin portions for an electric power component of an electric machine is known from document DE 10 2018 203 471 A1, the winding having at least one phase, the number of grooves being at least three, each phase having two parallel connected coil strands.

[0008] The coil strands are formed by a plurality of hairpin portions which are electrically connected to each other, wherein the conductor elements of the hairpin portions which form the boundary of one coil strand each form a connection pin. The pitch between two conductor elements of a hairpin portion which are next to each other is determined by the pitch of the grooves in which the conductor elements are inserted when the winding is assembled into the electric power component, for example the stator. This pitch is not referred to as the pitch width as usual here, but as the winding pitch, which is obtained by adding one to the number of grooves spanned. The winding pitch usually corresponds to the standard winding pitch, which is obtained by multiplying the number of grooves by the number of phases.

[0009] The winding has a circular circumference which is cylindrical, and is formed by an outer layer, an inner layer and a plurality of intermediate layers. Each winding turn, the two parallel connected coil strands of each phase are alternated once between two layers, so that the outer layer forms a double-layer structure with the first intermediate layer, possibly a double-layer structure with every two further intermediate layers which follow each other, and the last intermediate layer forms a double-layer structure with the inner layer.

[0010] Each strand has at least one larger winding pitch which differs from the standard winding pitch. The winding head of the hairpin portion with this larger winding pitch has a larger maximum winding head height than the winding head of the hairpin portion with the standard winding pitch.

[0011] In one embodiment, the strands in the last transition area (winding head) in the circumferential direction have a winding pitch which differs from the standard winding pitch (for example, specified as nine) by two grooves, so that the strands which pass through three immediately adjacent grooves in the circumferential direction are exchanged between the groove positions, more precisely between the outer grooves.

[0012] Observing the entire winding, all strands pass through the same groove positions of the same layer with the same frequency, only the position in the circumferential direction is different. As a result, the length and the resistance of the winding strands and the magnitude of the induced voltage are the same. This achieves a uniform and symmetrical current flow, which reduces the losses caused by the mutual inductance. The superimposed, rotating magnetic field which is generated when the winding is energized has the same uniformity at any time and at any rotational angle position. SUMMARY

[0013] It is an object of the present application to propose a winding with a hairpin portion, which does not require a larger installation space in the axial direction with the use of the hairpin portion. The superimposed and rotating magnetic field which is formed also has a better uniformity.

[0014] The object is achieved by a winding with hairpin portions for an electrical machine part, wherein the winding has at least one phase, a slot number of at least three, two parallel connected coil strands per phase, wherein the coil strands comprise at their ends a connection pin and a plurality of series connected hairpin portions, which comprise two side-by-side conductor elements each, which have two end portions on the twisting side of the winding and a winding head connecting the conductor elements on the turn-around area side of the winding, wherein the side-by-side conductor elements are at a distance to each other, which corresponds to the winding pitch, and the winding extends on an outer layer, an inner layer and a plurality of intermediate layers, forming a cylindrical circumference of the winding, wherein the winding has for each coil strand between the outer layer and the inner layer at least one winding pitch, which is a greater winding pitch than the standard winding pitch, wherein the standard pitch width is equal to the product of the slot number and the phase number, whereby the winding head of at least one hairpin portion has for each coil strand a greater maximum winding head height, which is greater than the maximum standard winding head height of the winding head of the other hairpin portions, which have a winding pitch equal to the standard winding pitch, and the winding has a plurality of covering pins, which have two conductor elements and a winding head, wherein one conductor element is arranged in the outer layer and the other conductor element is arranged in the inner layer, and the hairpin portion is arranged in the intermediate layer, wherein the covering pins each span or encompass the intermediate layer in an angular area, in which the local winding head height of the winding heads arranged radially one after the other is smaller than the greater maximum winding head height of the hairpin portion with the greater winding pitch minus the thickness of the covering pin in axial direction, so that the covering pin does not protrude in axial direction beyond the hairpin portion with the greater pitch width.

[0015] The winding pitch, which is different from the standard winding pitch, is preferably arranged in an angular area in the circumferential direction of the winding, in which the connection pin and the return pin are also located, since here also no covering pin is present and the greater winding head height of the axially arranged hairpin portion with the greater pitch width can protrude here from the height of the winding head with the standard pitch width.

[0016] The covering pins change the coil strand, which is formed only by the hairpin portion, and thus the current flow in the coil, whereby the generated magnetic field is influenced. They make the magnetic field formed around the individual coils more uniform and thus the superimposed magnetic field of the winding more uniform.

[0017] When the covering pins each span the intermediate layer in an angular area, in which the local winding head height of the winding heads arranged radially one after the other is smaller than the maximum standard winding head height of the hairpin portion with the standard winding pitch and the maximum covering pin head height is smaller than or equal to the greater maximum winding head height, it is advantageously possible to further reduce the installation space height.

[0018] Advantageously, the plurality of intermediate layers comprises an even number of intermediate layers, and the hairpin portions are arranged in two directly adjacent intermediate layers, respectively, forming a double layer structure.

[0019] Advantageously, the connecting pin is formed by an I-pin having only one conductor element, wherein the conductor element is connected at one end on the twisting side with one end of one hairpin portion and forms a free end at the other end on the turn region side. Thereby, the connecting pin can be arranged in the inner layer or in the outer layer and there occupies a vacant place of the conductor element where no covering pin is arranged.

[0020] Advantageously, the connecting pin is arranged in the outer layer, whereby the connecting pin can be connected with the power electronics in radial direction, preferably radially adjacent to the winding. It is particularly advantageous from a manufacturing point of view that on the twisting side the ends of all hairpin portions and the end of the connecting pin are deformed, twisted and pairwise connected to each other in equal half standard pitch width, or in a pitch width equal to the standard pitch width minus a difference of zero point five or minus one, layer by layer in opposite circumferential direction. This means that in all layers the ends arranged respectively forming the contact area are deformed with the same length and the same bending path, so that a standardized tool can be used to deform them simultaneously in each layer.

[0021] A stator with a winding according to the invention has the advantages achieved with this winding, wherein a motor, an electric axle drive and a motor vehicle using the motor according to the invention likewise have the advantages achieved with this winding. BRIEF DESCRIPTION OF DRAWINGS

[0022] The invention is explained below by means of embodiments in connection with the drawings. The drawings show:

[0023] Figure 1 A part of the winding shown is shown in perspective view looking towards the turn region side of the winding inserted into the recess of the stator;

[0024] Figure 2 A part of the winding according to Figure 1 is shown in a sectional view;

[0025] Figure 3 A part of the winding according to Figure 1 is shown in perspective view looking towards the twisting side of the winding inserted into the recess of the stator. DETAILED DESCRIPTION

[0026] The turn region side of the winding 1 according to the invention is shown in Figure 1 and its twisting side is shown in Figure 2The winding shown has at least one phase, a slot number of at least three, and two parallel connected coil strands per phase, as in the prior art. The winding shown here by way of example has three phases and a slot number of three.

[0027] The coil strands each comprise a plurality of series connected hairpin portions 300, wherein the ends of the coil strands on the turn region side 5 are formed by connecting pins 2 in the form of I-shaped pins. The hairpin portions 300 each comprise two side-by-side conductor elements 301 having two ends which form contact regions on the twist side 4 and winding heads 302 connecting the conductor elements on the turn region side 5, respectively. The two side-by-side conductor elements 301 are spaced apart from one another by a spacing corresponding to the pitch width.

[0028] The winding extends over an outer layer La, an inner layer Li and a plurality of intermediate layers Lm and jointly forms a winding 1 having a cylindrical circumferential surface, in this case exactly four intermediate layers Lm.

[0029] The hairpin portions 300 generally have a standard pitch width sWS which is equal to the product of the slot number and the phase number, with at least one exception per coil strand, namely a pitch width which is greater than the standard pitch width sWS, which is achieved by the winding head 302 of the hairpin portion 300. The winding head 302 of this hairpin portion thus has a maximum winding head height hg max which is greater than the maximum standard winding head height hs max of the winding heads 302 of the other hairpin portions 300 which have a pitch width equal to the standard pitch width sWS.

[0030] The winding according to the application differs from the winding known from the prior art, inter alia, in that the hairpin portions 300 are located between the outer layer La and the inner layer Li, arranged only on the intermediate layers Lm; and the winding 1 has a plurality of cover pins 600 with two conductor elements 601 and a winding head 602, wherein one conductor element 601 is arranged in the outer layer La and the other conductor element 601 is arranged in the inner layer Li, and the cover pin 600 spans the intermediate layers Lm. The key to the application is that the cover pins 600 each span an intermediate layer in an angular region in which the local winding head height hw of the winding heads 302 arranged radially one after the other is less than the greater maximum winding head height hg max of the hairpin portion 300 with the greater winding pitch gWS, minus the thickness of the cover pin 600 in the axial direction. In Figure 3In the illustration of Fig. 1, the angular region corresponds to the region between the two dot-dash lines. The local winding head heights hw are marked on three winding heads hw1 to hw3, which belong to one of the four intermediate layers Lm, respectively. The cover pin 600, which is denoted by reference 600, first spans one intermediate layer Lm at the uppermost winding head 302 arranged one above the other in the axial direction, which has the local winding head height hw1. Then, at the three winding heads 302 arranged one above the other in the axial direction, the uppermost of which has the local winding head height hw2, the cover pin spans the radially outer adjacent intermediate layer. Before the cover pin 600 spans the radially outermost fourth intermediate layer Lm at the uppermost winding head height, which is the winding head height hw3, it spans the third intermediate layer Lm.

[0031] By Figure 3 The true dimensions of the local winding head heights hw1 to hw4 cannot be derived here, it is merely intended to indicate that these dimensions are smaller than the maximum cover pin head height hc max of the cover pin 600 at the places where the cover pin 600 spans the respective intermediate layer Lm. max To this end, the winding head 602 of the cover pin 600 has a flat top in the angular region in which it spans the intermediate layer Lm, which has an at least approximately constant height, namely the maximum cover pin head height hc max , which is smaller than or equal to the greater maximum winding head height hg max . To this end, the angular range in which the cover pin 600 spans the intermediate layer Lm is chosen such that hw1 to hw4 are smaller than the greater maximum winding head height hg max . More precisely, hw1 to hw4 are at least reduced by the thickness of the cover pin 600 in the axial direction.

[0032] In Figure 3 the partial illustration of the winding shown in Fig. 2, the winding heads of the hairpin 300 can be clearly seen for two phases of two intermediate layers, which respectively protrude from three adjacent grooves with three conductor elements arranged side by side on the left side and enter into three adjacent grooves on the right side. Here, in the outermost grooves, the positions of the conductor elements alternate, whereby the pitch width of the two hairpins 300 involved differs from the standard pitch width sWS and is arranged one above the other in the axial direction. Since the coil strands of the two phases are offset by three grooves, a recess is formed between them, which the cover pin 600 can span over at least two intermediate layers Lm without increasing the overall height of the turn region side 5 winding 1.

[0033] As Figure 1It can be seen that, in the turn region side 5, the connecting pins 2 project from the grooves. The connecting pins 2 are formed by I-shaped pins. The connecting pins each have only one conductor element, wherein the conductor element is connected at one end in the twisting side 4 to one of the hairpin portions 300 and forms a free end at the other end in the turn region side 5. Since the connecting pins 2 project from the grooves into the outer layer La and remain in this layer as viewed in the radial direction, the angular region in which they are arranged preferably does not meet the conditions set for the angular region to be bridged by the covering pin 600.

[0034] In the twisting side 4, as shown in Figure 2 , the hairpin portion ends forming the contact region are deformed, twisted and connected to one another in pairs, layer by layer, in the opposite circumferential direction at equal half standard pitch widths sWS.

[0035] List of reference signs:

[0036] 1 winding

[0037] 2 connecting pin

[0038] 300 hairpin portion

[0039] 301 conductor element of the hairpin portion

[0040] 302 winding head of the hairpin portion

[0041] 4 twisting side

[0042] 5 turn region side

[0043] 600 covering pin

[0044] 601 conductor element of the covering pin

[0045] 602 winding head of the covering pin

[0046] La outer layer

[0047] Lm intermediate layer

[0048] Li inner layer

[0049] sWS standard pitch width

[0050] gWS greater pitch width

[0051] hs max maximum standard winding head height

[0052] hg max greater maximum winding head height

[0053] hc max maximum covering pin head height

[0054] hw local winding head height.

Claims

1. Winding (1) for electric components of an electric machine, with hairpin portions (300), wherein the winding has at least one phase, a slot number of at least three, two parallel connected coil strands per phase, wherein the coil strands have at their ends respectively a connecting pin (2) and comprise a plurality of serially connected hairpin portions (300), which respectively comprise two side-by-side, two-ended conductor elements (301) at the twisting side (4) of the winding (1) and a winding head (302) connecting the two conductor elements at the turn-around area side (5) of the winding (1), wherein the side-by-side conductor elements (301) have a spacing from each other, which equals the pitch width of the winding (1), and the winding (1) extends over an outer layer (La), an inner layer (Li) and a plurality of intermediate layers (Lm), forming a cylindrical peripheral surface of the winding (1), wherein said winding (1) has for each coil strand at least one pitch width between said outer layer (La) and said inner layer (Li), said pitch width being a greater pitch width (gWS) different from a standard pitch width (sWS) equal to the product of the number of slots and the number of phases, whereby the winding head (302) of at least one said hairpin portion (300) has for each coil strand a greater maximum winding head height (hg max ) compared to the winding head (302) of a further hairpin portion (300) having a pitch width equal to said standard pitch width (sWS) and having a maximum standard winding head height (hs max ), characterized in that The winding (1) has a plurality of covering pins (600) with two conductor elements (601) and a winding head (602), wherein one conductor element (601) is arranged in the outer layer (La) and the other conductor element (601) is arranged in the inner layer (Li), and the hairpin (300) is arranged in the intermediate layer (Lm), wherein the covering pins (600) each span the intermediate layer (Lm) in an angular region in which the local winding head height (hw) of the winding head (302) arranged radially successively is each less than the greater maximum winding head height (hg max ) of the hairpin (300) with the greater pitch width (gWS) minus the thickness of the covering pin (600) in the axial direction, so that the covering pin (600) does not axially protrude beyond the hairpin (300) with the greater pitch width (gWS).

2. Winding according to claim 1, characterized in that The covering pins (600) respectively cross the intermediate layers (Lm) of the winding (1) in an angular region in which the local winding head height (hw) of the winding heads (302) arranged radially successively is respectively smaller than the maximum standard winding head height (hs max ) of the hairpin portions (300) having a standard pitch width (sWS), and the maximum covering pin head height is smaller than or equal to the greater maximum winding head height (hg max ).

3. Winding according to claim 1 or 2, characterized in that the plurality of intermediate layers (Lm) is an even number of intermediate layers (Lm) and the hairpin portions (300) are respectively arranged in two of the intermediate layers (Lm) directly adjacent to each other, forming a double layer structure.

4. Winding according to any of the preceding claims, characterized in that the connecting pins (2) are formed by I-shaped pins, which have only one conductor element, wherein one end of the conductor element at the twisting side (4) is connected with one end of one of the hairpin portions (300) and the other end at the turn-around area side (5) forms a free end.

5. Winding according to claim 4, characterized in that the connecting pins (2) are arranged in the outer layer (La).

6. Winding according to claim 4 or 5, characterized in that at the twisting side (4) the ends of all hairpin portions (300) and the ends of the connecting pins (2) are deformed, twisted and pairwise connected to each other layer by layer in the opposite circumferential direction with an equal half standard pitch width (sWS).

7. Winding according to claim 4 or 5, characterized in that at the twisting side (4) the ends of all hairpin portions (300) and the ends of the connecting pins (2) are deformed, twisted and pairwise connected to each other layer by layer in the opposite circumferential direction with a pitch width which equals the half standard pitch width (sWS) minus one.

8. Winding according to claim 4 or 5, characterized in that at the twisting side (4) the ends of all hairpin portions (300) and the ends of the connecting pins (2) are deformed, twisted and pairwise connected to each other layer by layer in the opposite circumferential direction with a pitch width which equals the half standard pitch width (sWS) minus zero point five.

9. A stator for an electric machine, characterized in that The stator is provided with a winding (1) according to any of claims 1 to 8.

10. An electric machine characterized by The electric machine has a stator according to claim 9.

11. An electric axle drive, characterized in that The electrically driven axle drive has an electric machine according to claim 10.

12. Motor vehicle, characterized in that The motor vehicle has an electric axle drive according to claim 11.

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