Stator comprising slot closure body with integrated tool holder contour; and electric machine

Abstract

The invention relates to a stator (1) for an electric machine (10), comprising a base body (3) having several circumferentially distributed, radially inwardly opening grooves (2), a coil arrangement (4) wherein several longitudinal sections (5) of the coil arrangement (4) are arranged in each groove (2), and several groove closure bodies (6) arranged radially within the longitudinal sections (5), each of which has a strip-shaped base section (17) for closing a groove (2) on a radial inner surface (7) of the base body (3), wherein each groove closure body (6) has a tool-receiving contour (18) radially within the base section (17). The invention also relates to an electric machine (10) with this stator (1).

Description

[0001] The invention relates to a stator for an electric machine, in particular an electric drive motor of a motor vehicle, comprising a base body having several circumferentially distributed, radially inwardly opening grooves, a coil arrangement wherein several longitudinal sections of the coil arrangement are arranged in each groove, and several groove closure elements arranged radially within the longitudinal sections, each of which has a strip-shaped base section for closing a groove on a radial inner surface of the base body. The invention further relates to an electric machine with such a stator.

[0002] Electrical machines of this type with stators comprising slotted locking elements (also referred to as slotted / slotted locking wedges) are already well known. For example, reference is made to EP 2 568 576 A2, which discloses a cooling system integrated in a stator, wherein slotted wedges are used accordingly.

[0003] Depending on the cooling system implemented, it has been observed that a significant amount of coolant (usually oil) can penetrate the slots during operation. For example, oil enters the slots axially via the winding heads of the coil assembly. However, oil also enters the slots from a radial inside, particularly in the areas of the slot wedges, where it accumulates. Consequently, this results in increased resistance to the rotation of the rotor relative to the stator. Therefore, it is advantageous to design the slot closures with the thinnest possible walls to create spaces where the oil can drain away, thus optimizing the efficiency of the electric machine. At the same time, the slot closures should be able to be installed without damage.

[0004] The object of the present invention is therefore to further increase the efficiency of the electric machine, while the stator should still remain easy to assemble.

[0005] This is solved according to the invention by each groove closure body having a (mounting) tool receiving contour radially within the base section.

[0006] With this type of tool-receiving contour, the slot closure body can be gripped centrally by an assembly tool during installation, and the forces for (axially) inserting or pulling the slot closure body into the slot can be introduced with minimal bending stress on the lock body. This allows for the installation of particularly thin slot closure bodies. As a result, the efficiency loss at the rotor is significantly reduced. Consequently, the electric machine can be operated more efficiently.

[0007] Further advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

[0008] Therefore, it is also advantageous if the tool holder contour is formed on a thickened area of ​​the groove closure body. This prevents the structure of the groove closure body from being excessively weakened by the introduction of the tool holder contour.

[0009] In this regard, it has also proven advantageous if the thickened area has an inner contour that, at least in sections, features continuously inclined sections relative to a longitudinal axis. This creates an inner contour that, viewed axially, has a slope that causes the oil accumulating in the respective groove within the groove closure body to be automatically and selectively pumped out of the gap between the stator and rotor in a controlled axial direction due to the subsequent oil flow during rotor rotation. This further increases the efficiency of the electric machine.

[0010] This drainage of the oil is further enhanced if the thickened area has an overall roof-shaped inner contour.

[0011] If the tool holder contour has at least one stop flank angled perpendicular to the longitudinal axis, the force for inserting or pulling in the groove closure body can be applied with as little bending as possible.

[0012] Furthermore, it is advantageous if the tool holder contour has two axially spaced stop flanks, angled perpendicular to the longitudinal axis and facing away from each other. This allows the groove closure body to be gripped as firmly as possible by the tool.

[0013] Preferably, the stop flanks are formed by axial recesses / cutouts in the inclined sections. This makes the tool holder contour as easy to manufacture as possible.

[0014] If the thickened area between the two stop flanks has a constant inner diameter / a constant thickness, the tool holder contour is implemented with sufficient stability.

[0015] If the base section extends beyond the tool holder contour on both sides in the axial direction, the tool holder contour is positioned as centrally as possible for the respective assembly process, thereby keeping the overall load on the groove closure body as low as possible.

[0016] If the base section has a thickness of less than 1 mm, preferably less than 0.8 mm, and more preferably approximately 0.7 mm, a groove closure body with the thinnest possible walls is implemented. Preferably, the groove closure body is formed from a plastic material, such as a fiber-reinforced plastic.

[0017] In this regard, it is further advantageous if the inner contour projects inwards at least section by section over the radial inside of the base body.

[0018] Furthermore, it is advantageous if the inner contour is aligned axially centrally to the base body. This ensures the fastest possible drainage of excess oil. However, off-center arrangements may also be advantageous, particularly for further minimizing stress during assembly.

[0019] Furthermore, the invention relates to an electric machine for a motor vehicle, with a stator according to the invention in at least one of the embodiments described above and a rotor arranged radially inside the stator.

[0020] The invention will now be explained in more detail below with reference to figures, in which context various embodiments are also shown.

[0021] They show: Fig. 1 a longitudinal sectional view of a stator according to a first embodiment of the invention along an axially extending groove, wherein the formation of a groove closure body arranged towards a radial inner side of this groove is clearly visible, Fig. 2 a perspective view of a section of a groove closure body according to Fig. 1 of a side showing the tool holder contour, Fig. 3 a perspective view of the entire groove closure body according to Fig. 1, Fig. 4 a perspective view of a groove closure body designed according to a second embodiment with an off-center / decentralized tool holding contour, Fig. 5 a top view of the groove closure body according to Fig. 1, Fig. 6 a longitudinal section view of the groove closure body along the in Fig. 5 section line marked “VI-VI”, Fig. 7 a detailed view of the in Fig. 6 marked with “VII” of the tool holder contour, as well as Fig. 8 A perspective view of the longitudinally cut stator illustrating the assembly process of a slot closure body into a base body of the stator.

[0022] The figures are purely schematic and serve solely to illustrate the invention. The same elements are identified by the same reference symbols.

[0023] Combined with Fig. It should be noted generally that the stator 1 according to the invention, in its preferred embodiment, is implemented entirely in a ring shape and is used in an electric machine 10 (as a drive machine) of a motor vehicle. The electric machine 10 has, in the usual manner, a rotor 11 arranged radially inside the stator 1, which is rotatably mounted relative to the stator 1.

[0024] The rotor 11 is rotatably mounted about a rotational axis 21, which is aligned coaxially / concentrically with a longitudinal axis 8 of the stator 1. The directional terms used herein refer to this longitudinal axis 8, whereby axial direction is understood to mean a direction along / parallel to the longitudinal axis 8, radial direction a direction perpendicular to the longitudinal axis 8, and circumferential direction a direction along a circle concentrically around the longitudinal axis 8.

[0025] In Fig. Figure 1 shows a radial gap 14 between the stator 1 and the rotor 11. During operation of the electric machine 10, when the rotor 11 rotates, a fluid flow / oil flow is generated, which initially, due to the centrifugal force acting on the rotor 11, is directed radially outwards towards the stator 1. There, it finally encounters a radial inner surface 7 of the stator 1 / a base body 3 of the stator 1 and is deflected axially (to both sides).

[0026] The stator 1 has a base body 3 that is also formed entirely in a ring shape. The base body 3 is equipped with several radially inwardly opening grooves 2 distributed around its circumference. The base body 3 can, for example, be designed as a laminated core. Each groove 2 penetrates the base body 3 axially completely.

[0027] Each slot 2 contains several longitudinal sections 5 / coil sections of a coil arrangement 4 (such as a coil winding) of the stator 1, which are in Fig. The longitudinal sections 5 assigned to a groove 2 run essentially parallel to each other and are stacked radially. The coil arrangement 4 forms a winding head 15 on both axial sides / ends of the stator 1.

[0028] Each groove 2 is closed radially inwards by a groove closure body 6. This separately manufactured groove closure body 6 is in particular strip-shaped and has approximately the same length (axial extent) as the groove 2.

[0029] According to the invention, each groove closure body 6 is equipped with a [missing information] in the following Fig. 28 detailed tool holder contour 18. The tool holder contour 18 serves in particular to be gripped / received by an assembly tool designed in the opposite direction to it, which is not shown here for the sake of clarity, in order to Fig. 8 to be inserted axially into the groove 2 during assembly. The tool holding contour 18 therefore serves in particular to firmly hold the assembly tool in its longitudinal direction / along the longitudinal axis 8. For this purpose, the tool holding contour 18 has at least one, and in this case even two, stop flanks 20a, 20b, the further arrangement of which is explained in more detail below.

[0030] With Fig. 3, Fig. 5 and Fig. Figure 6 shows that the groove closure body 6 has a strip-shaped / band-shaped base section 17, which preferably has a constant thickness over its entire length. This thickness is preferably 0.7 mm.

[0031] Finally, the tool-holding contour 18 is positioned on a top surface of this base section 17. This top surface ultimately forms the radially inward-facing side of the groove closure body 6 in the assembled state and thus directly forms the inner surface 7 of the base body 3.

[0032] The tool-holding contour 18 is formed in particular on a thickened area 19 of the groove closure body 6. In other words, the thickened area 19 forms a protrusion on the upper surface of the base section 19. The thickened area 19 is in Fig. 3 arranged centrally to the overall length of the groove closure body 6. According to the alternative embodiment of the Fig. 4 However, it is also possible to arrange this thickening area 19 off-center, in particular offset from that axial end of the groove closure body 6 which is located during assembly according to Fig. 8 is to be inserted into groove 2 first.

[0033] The thickened area 19 forms a continuous, roof-shaped inner contour 9 of the groove closure body 6. The thickened area 19 / the inner contour 9 thus runs at an angle / inclination to the longitudinal axis 8 in sections. Axially centrally, the thickened area 19 / the inner contour 9 has a central section 12 of constant thickness / constant inner diameter. The central section 12 also forms the radially innermost region of the groove closure body 6. In the first embodiment, this central section 12 is positioned axially at the level of an axial center of the base body 3.

[0034] From the central section 12, the thickened area 19 / the inner contour 9 slopes down axially via inclined sections 13a, 13b, which directly adjoin the central section 12, until they transition into the base section 17. This widens the inner diameter of the slot closure body 6 / the stator 1 in the circumferential region of the slot closure body 6 from the central section 12 in the area of ​​these inclined sections 13a, 13b towards the base section 17.

[0035] Combined with Fig. Figure 7 further shows that the stop flanks 20a, 20b of the tool-holding contour 18, which are oriented perpendicular to the longitudinal axis 8, are each formed by a recess 16 provided in the thickened area 19. In particular, the recesses 16 are dimensioned such that the stop flanks 20a, 20b directly form the axial ends of the central section 12. In the transverse / circumferential direction, the recesses 16 are each bounded on both sides by a side web that directly forms the inclined section 13a, 13b. The recesses 16 are thus, overall, essentially wedge-shaped.

[0036] For example, in Fig. Figure 3 further shows that the stop faces 20a and 20b face away from each other. However, it is also possible in principle to arrange / design these stop faces in a different way and, for example, to provide only one stop face 20a or 20b.

[0037] In other words, in the electrical machine 1 according to the invention (preferably with wave winding technology), slot locking wedges (slot locking bodies 6) are used to prevent the winding / coil assembly 4 from radially inwards out of the stator slot (slot 2). Thus, relatively small slots / grooves are present on an inner contour of the stator 1.

[0038] The aim is to make the shape of the slot closure wedges so thin that, when the oil impacts the wedge radially, the rotational movement of the rotor 11 and the resulting centrifugal force create an axial flow of oil out of the air gap (gap area 14). This results in a very thin cross-section (height preferably between 0.4 mm and 0.8 mm) of the slot closure wedge along its axial length. Since thin slot closure wedges have lower stiffness, axial insertion into the stator 1 is more difficult. To facilitate insertion of this elastic slot closure wedge, a thicker section with a retaining lug (thickened area 19) is provided, at which the slot closure wedge can be inserted into the stator 1 using an assembly aid.

[0039] A groove-closing wedge with a roof-shaped projection is particularly preferred for removing oil from the air gap. Additionally, a retaining lug is located at the thicker section (thickened area 19), which allows the groove-closing wedge to be pulled into the groove 2. The thickened section (thickened area 19) does not need to be located centrally on the groove-closing wedge; it can also be positioned off-center. A groove 2 is located at the thickened section (thickened area 19), where an insertion tool can be positioned, minimizing the risk of damage (e.g., to the winding) or breakage of the groove-closing wedge during insertion. Reference symbol list 1 Stator 2 Nut 3 basic shapes 4 coil arrangement 5 Longitudinal section 6 Groove locking bodies 7 Inside of the base body 8 Longitudinal axis 9 Inner contour 10 electric machine 11 Rotor 12 Middle section 13a first inclined section 13b second inclined section 14 Gap area 15 winding head 16 Exclusion 17 Basic section 18 Tool holder contour 19 Thickening area 20a first impact flank 20b second attack flank 21 axis of rotation QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 568 576 A2

[0002]

Claims

[1] Stator (1) for an electric machine (10), comprising a base body (3) having several circumferentially distributed, radially inwardly open slots (2), a coil arrangement (4) wherein several longitudinal sections (5) of the coil arrangement (4) are arranged in each slot (2), and several slot closure bodies (6) arranged radially within the longitudinal sections (5), each having a strip-shaped base section (17) for closing a slot (2) on a radial inner side (7) of the base body (3), characterized by , that each groove closure body (6) has a tool receiving contour (18) radially within the base section (17). [2] Stator (1) according to claim 1, characterized by , that the tool receiving contour (18) is formed on a thickening area (19) of the groove closure body (6). [3] Stator (1) according to claim 2, characterized by, that the thickening area (19) has an inner contour (9) which has at least sectionally continuous inclined sections (13a, 13b) relative to a longitudinal axis (8). [4] Stator (1) according to claim 2 or 3, characterized by , that the thickening area (19) has an overall roof-shaped inner contour (9). [5] Stator (1) according to any one of claims 1 to 4, characterized by , that the tool holding contour (18) has at least one stop flank (20a, 20b) set perpendicular to the longitudinal axis (8). [6] Stator (1) according to any one of claims 1 to 5, characterized by , that the tool holding contour (18) has two axially spaced, perpendicular to the longitudinal axis (8) and facing away from each other stop flanks (20a, 20b). [7] Stator (1) according to claim 6, characterized by , that the thickening area (19) between the two stop flanks (20a, 20b) has a constant thickness. [8] Stator (1) according to any one of claims 1 to 7, characterized by , that the base section (17) extends beyond the tool holding contour (18) on both sides in the axial direction. [9] Stator (1) according to any one of claims 1 to 7, characterized by , that the base section (17) has a thickness of less than 1 mm. [10] Electric machine (10) for a motor vehicle, comprising a stator (1) according to one of claims 1 to 7 and a rotor (11) arranged radially inside the stator (1).

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