Stator having slot closure elements with integrated tool receiving contour; and electric machine

Abstract

The invention relates to a stator (1) for an electric machine (10), having: a main body (3) that has a plurality of slots (2) that are distributed in the circumferential direction and are open radially inwards; a coil arrangement (4), wherein a plurality of longitudinal portions (5) of the coil arrangement (4) are arranged in each slot (2); and a plurality of slot closure elements (6) that are arranged radially within the longitudinal portions (5) and each have a strip-shaped main portion (17) for closing a slot (2) on a radial inner side (7) of the main body (3), wherein each slot closure element (6) has a tool-receiving contour (18) radially within the main portion (17). The invention also relates to an electric machine (10) having said stator (1).

Description

[0001] P240238

[0002] - 1 -

[0003] Stator comprising slot closure body with integrated tool holder contour; and electric machine

[0004] 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.

[0005] Types of electrical machines 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 locking wedges are used accordingly.

[0006] 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. This results in increased resistance to the rotation of the rotor relative to the stator. Therefore, it is advantageous to implement the slot closures with the thinnest possible walls to create spaces in which 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. Suitable slot closures with a mounting or tool-receiving contour are known, for example, from US 2001 / 0004175 A1. P240238

[0007] - 2 -

[0008] 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.

[0009] This is solved according to the invention by each groove closure body having a (mounting) tool receiving contour radially within the base section and the tool receiving contour being formed on a thickening area of ​​the groove closure body and the thickening area also having a generally roof-shaped inner contour.

[0010] 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.

[0011] Further advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

[0012] According to the invention, the tool-holding 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-holding contour.

[0013] In this regard, it has also proven advantageous if the thickening area has an inner contour that, at least in sections, has continuously inclined sections relative to a longitudinal axis. This creates an inner contour that, viewed in an axial direction, has a slope / gradient that causes the oil accumulating in the respective groove within the groove closure body to flow out of the gap area P240238 in the axial direction due to the subsequent flow of oil during rotor rotation.

[0014] - 3 - is selectively extracted between the stator and rotor. This further increases the efficiency of the electric machine.

[0015] This drainage of the oil is further enhanced because the thickened area has a generally roof-shaped inner contour.

[0016] 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.

[0017] Furthermore, it is advantageous if the tool holder contour has two axially spaced, perpendicular to the longitudinal axis, and mutually opposed stop flanks. This allows the groove closure body to be gripped as firmly as possible by the tool.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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 wall thickness is implemented. Preferably, the groove closure body is formed from a plastic material, such as a fiber-reinforced plastic. P240238

[0022] - 4 -

[0023] 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.

[0024] 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.

[0025] 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.

[0026] The invention will now be explained in more detail below with reference to figures, in which context various embodiments are also shown.

[0027] They show:

[0028] Fig. 1 shows a longitudinal section of a stator according to a first embodiment of the invention along an axially extending groove, in which the formation of a groove closure body arranged towards a radial inner side of this groove is clearly visible.

[0029] Fig. 2 shows a perspective view of a section of a groove closure body according to Fig. 1 from a side showing the tool mounting contour,

[0030] Fig. 3 shows a perspective view of the entire groove closure body according to Fig. 1 ,

[0031] Fig. 4 shows a perspective view of a groove closure body designed according to a second embodiment with an off-center / decentralized tool mounting contour,

[0032] Fig. 5 shows a top view of the groove closure body according to Fig. 1, P240238

[0033] - 5 -

[0034] Fig. 6 shows a longitudinal section of the groove closure body along the section line marked “Vl-Vl” in Fig. 5,

[0035] Fig. 7 shows a detailed view of the tool holder contour marked “VII” in Fig. 6, as well as

[0036] Fig. 8 shows a perspective view of the stator cut in the longitudinal direction, illustrating the assembly process of a slot closure body into a base body of the stator.

[0037] The figures are purely schematic and serve solely to illustrate the invention. The same elements are identified by the same reference symbols.

[0038] In connection with Fig. 1, it should be noted in general 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.

[0039] 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.

[0040] Fig. 1 also 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 flows outwards in a radial direction from the rotor 11 due to the centrifugal force acting upon it. P240238

[0041] - 6 - tet is, towards the stator 1. There it finally meets a radial inner surface 7 of the stator 1 / of a base body 3 of the stator 1 and is deflected axially (to both sides).

[0042] 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.

[0043] In each slot 2, several longitudinal sections 5 / coil sections of a coil arrangement 4 (like a coil winding) of the stator 1, which can also be seen in Fig. 1, are inserted. The longitudinal sections 5 assigned to a slot 2 run essentially parallel to each other and are stacked radially. The coil arrangement 4 forms a winding head 15 at both axial sides / ends of the stator 1.

[0044] 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.

[0045] According to the invention, each groove closure body 6 is equipped with a tool-receiving contour 18, which is shown in detail in Figure 28 below. The tool-receiving 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, so that it can be inserted axially into the groove 2 during assembly, as shown in Figure 8. The tool-receiving contour 18 thus serves, in particular, to firmly receive the assembly tool in its longitudinal direction / along the longitudinal axis 8. For this purpose, the tool-receiving contour 18 has, in particular, at least one, and in this case, two stop flanks 20a, 20b, the further arrangement of which is explained in more detail below. P240238

[0046] - 7 -

[0047] Figures 3, 5 and 6 show that the groove closure body 6 has a strip-shaped / band-shaped base section 17, which preferably has a constant thickness along its entire length. This thickness is preferably 0.7 mm.

[0048] 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.

[0049] The tool-receiving 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. In Figure 3, the thickened area 19 is arranged centrally to the overall length of the groove closure body 6. However, according to the alternative embodiment shown in Figure 4, it is also possible to arrange this thickened area 19 off-center, in particular offset from the axial end of the groove closure body 6 that is to be inserted into the groove 2 first during assembly according to Figure 8.

[0050] 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.

[0051] From the central section 12, the thickening area 19 / the inner contour 9 slopes down in an axial direction via inclined sections 13a, 13b, which are directly adjacent to the central section 12, until they merge into the base section 17.

[0052] This increases the inner diameter of the slot closure body 6 / the stator 1 in the circumferential area of ​​the slot closure body 6 from the central section 12 P240238

[0053] - 8 - from in the area of ​​these the inclined sections 13a, 13b to the basic section 17.

[0054] In conjunction with Figure 7, it can further be seen 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.

[0055] For example, Figure 3 also 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.

[0056] 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.

[0057] The aim is to make the shape of the slot closure wedges so thin that, when the oil impacts the slot closure wedge radially, the rotational movement of the rotor 11 and the resulting centrifugal force create an axial flow direction of the 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 P240238 is used.

[0058] - 9 - provided with retaining lug (thickening area 19) on which the slot locking wedge can be inserted into the stator 1 by means of an assembly aid.

[0059] 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 thickening (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 thickening (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.

[0060] P240238

[0061] - 10 -

[0062] List of reference signs

[0063] 1 Stator

[0064] 2 Nut

[0065] 3 basic shapes

[0066] 4 coil arrangement

[0067] 5 Longitudinal section

[0068] 6 Groove locking bodies

[0069] 7 Inside of the base body

[0070] 8 Longitudinal axis

[0071] 9 Inner contour

[0072] 10 electric machine

[0073] 11 Rotor

[0074] 12 Middle section

[0075] 13a first inclined section

[0076] 13b second inclined section

[0077] 14 Gap area

[0078] 15 winding head

[0079] 16 Exclusion

[0080] 17 Basic section

[0081] 18 Tool holder contour

[0082] 19 Thickening area

[0083] 20a first impact flank

[0084] 20b second attack flank

[0085] 21 axis of rotation

Claims

P240238 - 11 - Patent claims 1. Stator (1) for an electric machine (10), comprising a base body (3) having several circumferentially distributed, radially inwardly open 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), characterized in that the tool-receiving contour (18) is formed on a thickening area (19) of the groove closure body (6) and the thickening area (19) has an overall roof-shaped inner contour (9).

2. Stator (1 ) according to claim 1 , characterized in that the thickening area (19) has an inner contour (9) which has at least sectionally continuously inclined inclined sections (13a, 13b) relative to a longitudinal axis (8).

3. Stator (1 ) according to one of claims 1 to 2, characterized in that the tool receiving contour (18) has at least one stop flank (20a, 20b) set perpendicular to the longitudinal axis (8).

4. Stator (1 ) according to one of claims 1 to 3, characterized in that the tool receiving contour (18) has two axially spaced stop flanks (20a, 20b) positioned perpendicular to the longitudinal axis (8) and facing away from each other.

5. Stator (1 ) according to claim 4, characterized in that the thickening area (19) between the two stop flanks (20a, 20b) has a constant thickness. P240238 - 12 - 6. Stator (1 ) according to one of claims 1 to 5, characterized in that the base section (17) projects beyond the tool receiving contour (18) on both sides in the axial direction.

7. Stator (1 ) according to one of claims 1 to 5, characterized in that the base section (17) has a thickness of less than 1 mm.

8. 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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