STATOR OF AN ELECTRICAL MACHINE WITH A SWITCHING DEVICE AND ELECTRICAL MACHINE

Description

[0001] The present invention relates to a stator of an electrical machine with a connection device for stator coils according to the preamble of claim 1 and to an electrical machine according to claim 4.

[0002] A stator of this type is already known from DE 10 2017 211168 A1. In this design, the interconnection device is mounted by means of pins projecting axially from the radially inner and outer legs of the winding bodies, which are hot-stitched to form a head. This simultaneously establishes and fixes both an axial and a radial end position of the interconnection device on the stator. A similar solution is described in DE 10 2016 200 115 A1.

[0003] DE 10 2015 225538 A1 discloses an electrical machine with a stator whose interconnection device is axially locked to the two radially spaced legs of the winding bodies of the stator coils with arrow-shaped locking elements of the interconnection device.

[0004] In the stator described in DE 10 2016 215716 A1, the interconnection device is positively locked to the radial walls or legs of several winding bodies and radially outside the coil receptacle to the outer legs of the winding bodies by means of gluing.

[0005] In the stator disclosed in DE 10 2017 216084 A1, the connection device is secured during axial joining by means of insulation displacement connectors projecting axially from the connection device, which simultaneously act as locking elements and are pressed into receiving pockets on the stator in a centering manner. Furthermore, this is achieved by means of plastic centering pins projecting axially from an insulating lamella provided on the end face of the stator, which engage in corresponding centering receptacles of the connection device and can be hot-stitched to form a head.

[0006] In the stator of DE 10 2016 218129 A1, the connecting device is arranged between and attached to the radially inner and radially outer legs of the winding bodies. For this purpose, radial or axial projections are formed on the connecting device, which engage in corresponding recesses on the inner and outer legs of the winding bodies, thus supporting the connecting device radially and circumferentially. The axial fixation of the connecting device to the legs or to the winding itself is achieved by means of adhesive. Alternatively, the projections of the connecting device can also engage in a space between two adjacent stator coils, in particular in recesses formed jointly by two winding bodies.

[0007] According to DE 10 2009 001 830 A1, the connection device is fixed in the radial plane with a cylindrical wall area on a common inner or outer circumferential surface formed by the legs of the winding bodies, and the connection device rests with a radial wall area on a stop surface formed on the stator and is received and secured in position by axial pins projecting from the legs of the winding bodies.

[0008] In the solution proposed in JP 2007 288 821 A, the connection device on the stator is also mounted radially between the legs of the winding bodies. U-shaped coil ends are guided radially out of a winding area on both sides through slots in the legs of the winding bodies and bent axially, allowing radially projecting connection areas of the connection device to be engaged or interlocked in a manner similar to a locking mechanism, thus achieving mutual axial fixation of the connection partners.

[0009] Finally, in the stator disclosed in US 2015 / 188376 A1, the interconnection device is designed, at least segmentally, with two radially spaced wall sections projecting axially from a main body in the direction of the winding. An insulator or winding support with two axially projecting legs, which define a winding area of ​​coils, is formed at the end face of the stator. During assembly of the interconnection device, the wall sections provided there can positively engage the legs outside the winding area, with the outer wall section forming an axial snap-fit ​​connection with the associated leg.

[0010] Starting from this prior art, the present invention is based on the objective of further improving a stator of an electric machine with a connection device for stator coils of the type mentioned above, and such an electric machine. In particular, improved radial support of the connection device on the stator and thus improved resistance to operational vibrations of the electric machine are sought.

[0011] This problem is solved by a stator having the features of claim 1 and by an electrical machine according to claim 4.

[0012] Advantageous embodiments and further developments of the invention can be found in the dependent claims, the following description and the accompanying figures.

[0013] A stator for an electric machine is proposed, comprising an annular laminated core formed around a central axis. Stator coils with coil ends are arranged on this core by means of winding bodies. The stator further includes a connection device with several mutually insulated connecting conductors, with coil connection areas for connecting the stator coils. The connection device is mounted to the stator in an axial direction relative to the stator coils. In the assembled state, it is positioned adjacent to the stator coils and is fixed to several of the winding bodies by axial connecting means, forming a plurality of axial connections. Axial stops acting on both sides are provided, between which the connection device is essentially free of play and which are formed by the axial connecting means themselves.

[0014] In the proposed stator, the interconnection device has radial support means for interaction with the winding bodies, which are designed independently of the axial connecting means.

[0015] The proposed mutual design of the interconnection device and the winding body has a positive effect on the mechanical and dynamic strength of the entire stator assembly. Since the interconnection device is directly connected to the stator and forms a functional unit of the stator, it can vibrate together with the electric machine during operation, particularly when used as a traction motor in a motor vehicle. Relative movements between the stator and the interconnection device often occur, whereby the coil ends in particular are subjected to high-frequency alternating mechanical stress, and wire breakage can occur. The radial support of the interconnection device proposed here can mitigate the effects of vibrations and other factors.Vibrations and relative movements of the stator coils and the interconnection device are significantly reduced, thereby noticeably reducing the risk of wire breakage.

[0016] According to the invention, a functional separation is achieved with regard to the fixing of the interconnection device to the winding bodies of the stator, whereby axial connecting means and radial support means are designed to be functionally independent of one another. The axial connecting means thus primarily serve to establish and secure a defined axial position of the interconnection device. The radial support means correspondingly primarily serve to establish and secure a defined radial position of the interconnection device and, in particular, to reduce and prevent periodic bending stress on the coil ends caused by mutual radial movement of the coils relative to the interconnection device. In this way, radial stress on the axial connecting means can be significantly reduced.At the same time, the formation of independent radial support means can permanently achieve improved radial positioning of the interconnection device on the stator.

[0017] The axial connections, or axial fasteners, feature a radial gap to allow for radial play. This means that the axial connection partners permit mutual radial movement without noticeably affecting the radial position of the other connection partner. Therefore, the axial fasteners do not require specific radial dimensional accuracy. This allows the axial fasteners to be even better decoupled and relieved of any remaining radial displacements of the interconnection device relative to the coils.

[0018] A winding body has a winding area formed by a winding support and two legs that define the winding area axially and are connected to the winding support. The axial connecting elements are formed on the legs of the winding body. The radial support elements of the connection device can act radially on one or both sides. For this purpose, the radial support elements can be single or multiple, particularly double, and accordingly interact with one or both legs of a winding body. One of the aforementioned support elements can engage radially on the inside or outside of a leg of a winding body and fix the connection device to the stator in a predetermined radial position.

[0019] To achieve high stator stiffness, the radial support elements are designed to interact with both legs on one of the winding bodies, forming a first and, if necessary, a second support area. It has proven advantageous to center the interconnection assembly relative to the stator coils using only one of these two support areas. Ideally, with a precisely annular interconnection assembly and / or arrangement of the winding bodies, the components, given a specific axial position relative to each other, come into contact with each other only at one of the support areas.If, due to manufacturing and assembly tolerances, the connection device and / or the arrangement of the winding bodies deviates from an ideal circular annular shape, and one of the components is, for example, slightly elliptically deformed, the surfaces of the winding bodies that cooperate to form the second support area can also come into contact with each other and cause radial fixation. It is particularly space-saving to form the support areas radially between the axial connecting elements.

[0020] The aforementioned concept is realized according to the invention in that the support means have a first support surface and a second support surface radially spaced apart from it, the first and second support surfaces being radially opposite each other. The first support surface and a cooperating guide section of one of the legs extend parallel to the central axis, i.e., along the axial joining direction of the connecting device, and form the first support area. The second support surface and a cooperating contact section of the other leg, on the other hand, are inclined at an acute angle to the central axis in the axial joining direction and, if necessary, form the second support area.In this way, a predefined radial positional relationship between the first support surface and the guide section can be generated during the axial joining of the connecting device. This relationship is independent of the relative axial position of the joining partners. In contrast, a radial positional relationship is generated between the second support surface and the second mounting section as needed. This radial positional relationship is less predefined than the one described above and is therefore radially variable within predefined limits. The radial position generated during joining is particularly dependent on the specific radial manufacturing and / or assembly tolerances of the joining partners.

[0021] To avoid undesirable excessive mechanical stress, it is advantageous to position the coil connection areas of the connecting conductors adjacent to the first support area. This ensures that the coil ends and their contact points at the coil connection areas are particularly well fixed in place and protected against wire breakage. It is especially advantageous to position the coil connection areas closer to the first support area than to the second. Furthermore, the coil connection areas of the connecting conductors can be advantageously positioned adjacent to the support area that centers the wiring device.

[0022] According to a further spatial optimization of the arrangement, the two coil ends of a coil can exit the winding area on the same leg of one of the winding bodies. The first support area in the circumferential direction on the stator can then be formed between these coil ends of the legs, thus saving space.

[0023] Furthermore, an electric machine with a rotor and a stator is proposed, wherein the stator has at least one of the features described above.

[0024] The invention is explained below by way of example with reference to an embodiment shown in the figures.

[0025] They show: Fig. 1 a schematic representation of an upper half-plane of an electric machine with a stator and a switching device; Fig. 2 a perspective partial view of the stator with a view of the switching device; Fig. 3 an enlarged section of the representation ofFig. 2 with a view of a radially inner region of the stator; Fig. 4 an axial sectional view of the stator of Fig. 2 in a plane of axial connecting means of a winding body with the interconnection device; Fig. 5 a further axial sectional view of the stator of Fig. 2 in a plane outside the in Fig. 4 shown connecting elements.

[0026] Fig. 1 Figure 1 schematically and in a simplified form shows an electric machine 1, which is presented here only as an example of a permanent magnet synchronous machine with an internal rotor design. The electric machine 1 is specifically designed for use as a drive system in a hybrid or electric vehicle and can therefore be arranged in the drive train of such a vehicle.

[0027] The electric machine 1 initially comprises a rotor 8 rotatable about a rotor shaft 2 with an axis of rotation A, which is radially surrounded on the outside by a stator 10, forming a radial air gap 9. The rotor 8 includes a laminated rotor lamination stack 8a with a plurality of circumferentially spaced permanent magnets 8b. The stator 10 comprises an annular stator support 10a, in the central recess of which an annular lamination stack 11, also formed from laminated laminations, is arranged. The lamination stack 11 is segmented circumferentially and assembled into a closed ring by a plurality of identical stator segments. The axis of rotation A thus also forms the central axis A of the machine 1. The stator support 10a can be, as in Fig. 1 The images simultaneously represent an outer casing or an intermediate casing of the electric machine 1.

[0028] The laminated core 11 comprises an annular stator yoke abutting the stator support 10a and radially inward-projecting teeth which are fitted with several stator coils 16 to form a stator winding. The stator coils 16 are designed as single-tooth coils and are wound around the teeth 11c with the aid of two insulating or winding bodies 12a, 12b made of a heat-resistant plastic, using copper wire, and are secured there against slippage. The winding bodies 12a, b each comprise a base area or winding support 13 abutting the end face of the laminated core 11 and two legs 14, 15 projecting axially from the stator 10 at approximately right angles, which define a winding area 17 in the radial direction. Thus, the stator coils 16 form winding heads at the end faces of the stator 10, which project axially beyond the laminated core 11.

[0029] The coils 16 are electrically assigned to individual strands, for which the coil ends 16a, b are connected by means of a Fig. 1 The interconnection device 20, shown only schematically, is interconnected in a predetermined manner. For this purpose, the interconnection device 20 comprises several mutually insulated connecting conductors 22, 24, 26, which have circumferentially spaced coil connection areas 22a, 24a, 26a for contacting the coil ends 16a, b. The interconnection device 20 is designed as a prefabricated metal-plastic composite element in which the connecting conductors 22, 24, 26, except for the coil connection areas 22a, 24a, 26a, are overmolded with plastic, thus covering the inner and outer circumferential surfaces and the end faces with plastic.

[0030] As in Fig. 1 As can be seen, the interconnection device 20 is arranged in an axial direction to the stator coils 16 and is located directly adjacent to them axially. The interconnection device 20 is further connected via power connection areas 22b, 24b, 26b of the connecting conductors 22-26 to a power electronics unit 60 and a control electronics unit 62 to an electrical power source 64, which can supply the stator coils 16 with a current of variable phase and amplitude to operate the electric machine 1.

[0031] The connecting conductors 22-26 are manufactured from a copper semi-finished product, in particular from a copper plate or copper sheet, using stamping and forming processes as ring discs. As in Fig. 1 As shown, the ring disks on the stator 16 are arranged coaxially to the central axis A and stacked axially to each other.

[0032] In the embodiment described here, the coil connection areas 22a-26a are located on the radially inner circumferential region of the connecting conductors 22-26 and are axially aligned, as are the coil ends 16a, b. The coil connection areas 22a, 24a, 26a and the coil ends 16a, b are positioned parallel to each other and are located essentially on the same pitch circle for interconnection. The power connection areas 22b, 24b, 26b are formed on the interconnection device 20 as axially projecting copper connection lugs, which can be integrally formed with the connecting conductors 22-26 or, in the case of a multi-part design, preferably soldered or welded to them.

[0033] In the illustrated embodiment, the coil ends 16a, b are connected to the connecting conductors 22-26 by means of a delta connection. The winding start with coil end 16a and the winding end with coil end 16b both emerge radially inwards from the winding area 17 of a coil 16. For the connection, two adjacent coil ends 16a, b of two circumferentially adjacent coils 16 are also connected to directly adjacent coil connection areas 22a, 24a, 26a of one of the connecting conductors 22-26. The contact between the coil ends 16a, b and the connecting conductors 22-26 is achieved by a metallurgical bond, in particular by soldering or welding.

[0034] The precise fastening of the wiring device 20 is particularly well illustrated by the Fig. 2-5 recognizable, whereby for the purpose of better clarity the coils 16 with the coil ends 16a, b in the Fig. 4 , 5The connection device 20 is fixed to one of the winding bodies 12a at both the radially outer leg 15 and the radially inner leg 14. In the exemplary embodiment, the connection device 20 has several radially inner and radially outer mounting openings 20a, b distributed circumferentially. Corresponding to this radial and circumferential distribution, axial connecting elements 30a, b in the form of axially projecting pins are formed on the legs 14, 15. These pins can receive the prefabricated connection device 20 up to the point where it abuts the shoulder areas 46 of the connecting elements 30a, b or the pins, and can then, for example, be fixed in the assumed axial position by subsequent hot riveting, forming head areas 48.The shoulder areas 46 and the head areas 48 of the pins 30a, b thus represent axial stops acting on both sides, between which the interconnection device 20 is essentially free of play.

[0035] The axial connections 32a, b created by means of the axial connecting elements 30a, b have a radial gap 30 or an annular gap 30 between the pins 30a, b and the interconnection device 20, so that the connecting partners allow mutual radial play at these positions. The axial connecting elements 30a, b thus serve to axially fix the interconnection device 20 and are essentially decoupled and thereby relieved of any minor radial displacements of the interconnection device 20 relative to the coils 16 that may occur.

[0036] Radial support means 40, 41 are provided for the mutually defined radial positioning of the interconnection device 20 and the winding bodies 12a. These support means 40, 41 are configured on the interconnection device 20 as two axial projections each, extending axially in the direction of a winding body 12a. The support means 40, 41 are thus structurally separate and functionally independent from the axial connecting means 30a, b.

[0037] How best to in the Fig. 4 , 5 As can be seen, each projection 40, 41 interacts with one of the two legs 14, 15 of a coiled body 12a and forms a first or a second support area 42, 44 there.

[0038] The projections or support elements 40, 41 have a first support surface 40a and a second support surface 41a radially spaced from it. The first support surface 40a and a cooperating guide section 14a of the radially inner leg 14 extend parallel to the central axis A, i.e., along the axial joining direction of the connecting device 20, and form the first support area 42. The second support surface 41a and a cooperating contact section 15a of the radially outer leg 15, on the other hand, are inclined relative to the central axis A and the joining direction and form a second support area 44.

[0039] During the axial joining of the interconnection device 20, a predefined radial positional relationship can be established between the first support surface 40a and the guide section 14a, which is independent of the mutual axial position of the joining partners. In contrast, a radial positional relationship can be generated, if required, between the second support surface 41a and the contact section 15a, which is less predefined and thus radially variable within specified limits, and which depends on the respective existing radial manufacturing and / or assembly tolerances of the joining partners. Fig. 4 , 5A gap 50 is visible between the second support surface 41a and the assembly section 15a, so that there is no mutual contact between the interconnection device 20 and the winding body 12a in this area, and the second support area 44 is not engaged. This means that in this case, the interconnection device 20 and / or the arrangement of the winding bodies 12a are ideally circular, and engagement of the support area 44 is not required. The centering of the interconnection device 20 relative to the stator coils 16 is thus achieved solely by means of the support area 42.

[0040] As can be seen in the figures, the coil connection areas 22a, 24a, 26a are arranged closer to the first support area 42 than to the second support area 44. Furthermore, the support areas 42, 44 are radially positioned between the axial connecting means 30a, b. The two coil ends 16a, b of a coil 16 also emerge together from the winding area 17 on the inner leg 14 of a winding body 12a. The first support area 42 is formed circumferentially on the stator 10, space-savingly positioned between the coil ends 16a, 16b of each leg 14. Bezugszeichen

[0041] 1 electric machine 8 rotor 8a rotor lamination stack 8b permanent magnet 9 air gap 10 stator 10a stator support 11 stator lamination stack 11a stator segment 11b stator yoke 11c stator tooth 12a, b winding body 13 winding support 14 leg 14a guide section 15 leg 15a mounting section 16 coil 16a coil end 16b coil end 17 winding area 20 connection device 20a, b mounting opening 22 connecting conductor 22a coil connection area 22b power connection area 24 connecting conductor 24a coil connection area 24b power connection area 26 connecting conductor 26a coil connection area 26b power connection area 30a, b axial connecting means 33 radial gap 32a, b Axial connection 40 Radial support means 40a Support surface 41 Radial support means 41a Support surface 42 First support area 44 Second support area 46 Axial stop 48 Axial stop 50 Gap 60 Power electronics 62 Control electronics 64 Power source A Center axis

Claims

1. Stator (10) of an electric machine (1) having - an annular laminated core (11) which is formed around a centre axis (A) and on which stator coils (16) with coil ends (16a, b) are arranged by means of winding formers (12a, 12b), wherein - a winding former (12a) has a winding region (17), which is formed by a winding carrier (13) and two radially inner and radially outer limbs (14, 15) delimiting the winding region (17) in the axial direction and connected to the winding carrier (13), and having - an interconnection device (20) having a plurality of mutually insulated connecting conductors (22-26), which have coil connection regions (22a-26a) for the interconnection of the stator coils (16), wherein - the interconnection device (20) is joined to the stator coils (16) in an axial joining direction and arranged adjacent thereto, and wherein - the interconnection device (20) is secured to the winding formers (12a) by axial connecting means (30a, b) to form a multiplicity of axial connections (32a, b), wherein - the interconnection device (20) on one of the winding formers (12a) is secured in each case to the radially outer limb (15) and to the radially inner limb (14), for which purpose - a plurality of radially inner and radially outer fastening openings (20a, b), distributed in the circumferential direction, are provided on the interconnection device (20), and wherein - the axial connecting means (30a, b) are in the form of axially projecting pins, which can receive the prefabricated interconnection device (20) until it abuts against shoulder regions (46) of the pins (30a, b) and can then fix it in the assumed axial position with the formation of head regions (48) and thus axial stops (46, 48) that act on both sides, and wherein - the axial connections (32a, b) have a radial gap (33) for allowing a mutual radial play of the connecting partners, characterized in that - the interconnection device (20) has radial supporting means (40, 41) for cooperating with the winding formers (12a), which are formed independently of the axial connecting means (30a, b), wherein - the radial supporting means (40, 41) are designed as two axial projections (40, 41) extending axially in the direction of a winding former (12a), and wherein - the axial projections (40, 41) extend into the winding region (17), wherein - the supporting means (40, 41) have a first support surface (40a) and a second support surface (41a), which is radially spaced from said first support surface and radially opposite the first support surface (40a), wherein - the first support surfaces (40a) and a guide portion (14a), cooperating therewith, of one of the limbs (14) extend parallel to the centre axis (A) and form the first support region (42), and wherein - the second support surface (41 a) and a contact portion (15a), cooperating therewith, of the other limb (15) are constructed at an acute angle with respect to the centre axis (A) in the axial joining direction and form the second support region (44), and wherein - the support regions (42, 44) are formed radially between the axial connecting means (30a, b), and wherein - the radial supporting means (40, 41) form a first support region (42) and, if necessary, a second support region (44), wherein a centring of the interconnection device (20) with respect to the stator coils (16) takes place by means of only one of the two support regions (42, 44).

2. Stator according to Claim 1, characterized in that the coil connection regions (22a-26a) of the connecting conductors (22 - 26) are arranged adjacent to the support region (42) that brings about the centring of the interconnection device (20).

3. Stator according to Claim 1 or 2, characterized in that the two coil ends (16a, b) of a coil (16) exit the winding region (17) at the same limb (14, 15) of one of the winding formers (12a), wherein the first support region (42) is formed on the stator (10) in the circumferential direction, between these coil ends (16a, 16b) of the limbs (14, 15).

4. Electric machine (1) having a rotor (8) and having a stator (10), wherein the stator (10) is constructed according to at least one of Claims 1 - 3.