Stator with roof-shaped slot closure body for draining oil; and electrical machine

Abstract

The invention relates to a stator (1) for an electrical machine (10), comprising a base body (3) having a plurality of circumferentially distributed, radially inwardly open slots (2), a coil arrangement (4), wherein a plurality of longitudinal sections (5) of the coil arrangement (4) are arranged in each slot (2), and a plurality of slot closure bodies (6), each of which closes a slot (2) towards a radial inner side (7) of the base body (3), radially inside the longitudinal sections (5), and wherein each slot closure body (6) has an inner contour region (9) extending in the axial direction and inclined with respect to a longitudinal axis (8). The invention further relates to an electrical machine (10) comprising this stator (1).

Description

[0001] The invention relates to a stator for an electrical machine, comprising a base body having a plurality of circumferentially distributed slots (each of which opens radially inward), a coil arrangement, wherein a plurality of longitudinal sections of the coil arrangement are arranged in each slot, and a plurality of slot closure bodies, each of which closes a slot toward a radial inner side of the base body, radially within the longitudinal sections. Furthermore, the invention relates to an electrical machine having such a stator.

[0002] Generic electrical machines with stators featuring slot-locking bodies (also referred to as slot-locking wedges) are already well known. For example, reference is made to EP 2 568 576 A2, which discloses a cooling system integrated into a stator, in which slot wedges are used accordingly.

[0003] Depending on the cooling system implemented, it has been found that a significant amount of coolant (usually oil) can penetrate into 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 the radial inside, particularly in the areas of the slot wedges, where it accumulates. Overall, this results in increased resistance to the rotation of a rotor relative to the stator.

[0004] It is therefore the object of the present invention to further increase the efficiency of the electrical machine, while keeping the structure of the stator as simple as possible.

[0005] This is achieved according to the invention in that each slot closure body has an inner contour region running in the axial direction and inclined relative to a longitudinal axis (of the stator / base body).

[0006] This inner contour area thus exhibits an incline / decline in the axial direction, which results in the oil accumulating in the respective groove within the slot seal body being automatically and specifically expelled axially from the gap area between the stator and rotor due to the subsequent oil flow during rotor rotation. This significantly reduces the efficiency loss at the rotor. Consequently, the electric machine can be operated more efficiently.

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

[0008] Accordingly, it is also advantageous if the inner contour area is roof-shaped, i.e., has a roof-shaped profile when viewed in longitudinal section. This makes the groove seal body easy to manufacture and, at the same time, prepares it for rapid oil drainage.

[0009] In this regard, it has also proven advantageous if the inner contour region has an axial center section that directly forms a radially innermost region of the slot closure body. Preferably, the center section provides a separation geometry in an axial center of the stator / base body, at which the oil is directed either to a first axial side or to a second axial side of the stator opposite the first axial side.

[0010] Furthermore, it is advantageous if the inner contour region has two bevel sections, each axially adjacent to the central section, wherein an inner diameter of the bevel sections (ie an inner diameter of the stator at the bevel sections directly forming the radial inner side) widens with increasing distance from the central section.

[0011] If the sloped sections also have a continuous gradient, the flow is led out of the gap area between the rotor and stator as quickly as possible.

[0012] In this regard, it is further advantageous if the inner contour region (in particular the central section) protrudes inwards at least in sections beyond the radial inner side of the base body.

[0013] Furthermore, it is advantageous if the inner contour area is aligned axially centrally with the base body. This ensures the fastest possible drainage of excess oil.

[0014] Furthermore, the invention relates to an electric machine for a motor vehicle, with a stator according to the invention according to at least one of the previously described embodiments and a rotor arranged radially inside the stator.

[0015] The invention will now be explained in more detail below with reference to figures.

[0016] They show: Fig. 1 a longitudinal sectional view of a stator according to the invention according to a preferred embodiment along an axially extending groove, wherein the formation of a groove closure body arranged towards a radial inner side of this groove can be clearly seen, Fig. 2 a schematic cross-sectional view of an electrical machine comprising the stator according to Fig. 1 and a rotor, with the oil flows generated during operation shown schematically, and Fig. 3 a detailed view of the Fig. 1 area marked “III” to illustrate an oil flow deflected at a central section of the slot closure body during operation.

[0017] The figures are merely schematic and serve solely to facilitate understanding of the invention. The same elements are designated by the same reference numerals.

[0018] First of all, in connection with Fig. 2, it should be noted that the stator 1 according to the invention, in its preferred embodiment, is entirely annular and is used in an electric machine 10 (as a drive motor) of a motor vehicle. In addition to the stator 1, the electric machine 10 conventionally has a rotor 11 arranged radially inside the stator 1, which is rotatably mounted relative to the stator 1.

[0019] The rotor 11 is mounted for rotation about an axis of rotation that is aligned coaxially / concentrically with a longitudinal axis 8 of the stator 1. The directional information used herein refers to this longitudinal axis 8, whereby the axial / axial direction is understood to mean a direction along / parallel to the longitudinal axis 8, the radial / radial direction is understood to mean a direction perpendicular to the longitudinal axis 8, and the circumferential direction is understood to mean a direction along a circular line concentrically encircling the longitudinal axis 8.

[0020] In Fig. 2 shows the gap area 14 between the stator 1 and the rotor 11 in more detail. It can be seen that during operation of the electric machine 10, upon rotation of the rotor 11, a fluid flow / oil flow is generated which, due to the acting centrifugal force, is initially directed radially outwards from the rotor 11, towards the stator 1. There it finally encounters a radial inner side 7 of the stator 1 / a base body 3 of the stator 1 and is deflected axially, as shown in more detail in Fig. 3 recognizable.

[0021] Returning to Fig. 1 shows that the stator 1 has a completely annular base body 3. The base body 3 is equipped with several grooves 2 distributed in the circumferential direction and opening radially inward. The base body 3 can, for example, be designed as a laminated core. Each groove 2 penetrates the base body 3 axially.

[0022] In each slot 2 there are several longitudinal sections 5 / coil sections of a coil arrangement 4 (such as a coil winding) of the stator 1, which are arranged in Fig. 1. The longitudinal sections 5 assigned to a slot 2 run essentially parallel to one another and are arranged stacked in the radial direction. The coil arrangement 4 forms a winding head 15 on both axial sides / ends of the stator 1.

[0023] Each groove 2 is closed in the radial direction by a groove closure body 6. This separately manufactured groove closure body 6 is particularly strip-shaped and has approximately the same length (axial extent) as the groove 2.

[0024] According to the invention, each slot closure body 6 is provided with a roof-shaped inner contour area 9, which is inclined in sections relative to the longitudinal axis 8. In conjunction with Fig. In this regard, it can be seen in Figure 3 that the inner contour region 9 has a central section 12, which simultaneously forms the radially innermost region of the slot closure body 6. This central section 12 is positioned axially at the level of an axial center of the base body 3. From this central section 12, a beveled section 13a, 13b, which directly borders the central section 12, slopes down in the axial direction on both sides, so that an inner diameter of the slot closure body 6 / of the stator 1 widens in the circumferential region of the slot closure body 6 from the central section 12 in the region of these beveled sections 13a, 13b.

[0025] In principle, it is possible to extend the beveled sections 13a, 13b axially from the central section 12 to the axial ends of the grooves 2. Preferably, however, as implemented in the present invention, the beveled sections 13a, 13b are formed only in an axial partial section of the groove closure body 6. Directly adjacent to the respective beveled section 13a, 13b of the inner contour region 9 is a side region 16a, 16b having a continuous inner diameter (i.e., running parallel to the longitudinal axis 8).

[0026] In other words, slot closure wedges are used in the electrical machine 1 according to the invention (preferably with wave winding technology) to prevent the winding / coil arrangement 4 from radially inwardly dislodging from the stator slot (slot 2). Thus, relatively small slots / grooves are provided on an inner contour of the stator 1.

[0027] The shape of the slotted wedge is now designed so that when the oil radially impacts the slotted wedge, the rotational movement of the rotor 11 and the resulting centrifugal force create an axial flow direction of the oil from the air gap (gap area 14). This results in a roof-shaped cross-section of the slotted wedge over its axial length.

[0028] Fig. 1 shows the arrangement of the components in the stator in a section along the stator axis / longitudinal axis 8. If oil is in the air gap of the electric motor, it is displaced radially outwards by the rotational movement of the rotor 11 ( Fig. 2).

[0029] When the radially displaced oil hits the bevel (bevel sections 13a, 13b) of the slotted closure wedge, this results in a predetermined axial flow direction of the oil ( Fig.3). This axial flow direction causes the oil to flow out of the air gap at both axial ends of stator 1. The helix angle and extension of the "roof shape" are optimized for the specific application. List of reference symbols 1 stator 2 grooves 3 basic bodies 4 coil arrangement 5 Longitudinal section 6 slot lock body 7 Inside of the base body 8 Longitudinal axis 9 Inner contour area 10 machines 11 Rotor 12 Middle section 13a first slope section 13b second slope section 14 gap area 15 winding head 16a first side area 16b second side area QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] EP 2 568 576 A2

[0002]

Claims

[1] Stator (1) for an electrical machine (10), with a base body (3) having a plurality of circumferentially distributed, radially inwardly open slots (2), with a coil arrangement (4), wherein in each slot (2) a plurality of longitudinal sections (5) of the coil arrangement (4) are arranged, and with a plurality of slot closure bodies (6), each of which closes a slot (2) towards a radial inner side (7) of the base body (3), radially inside the longitudinal sections (5), characterized by that each slot closure body (6) has an inner contour region (9) extending in the axial direction and inclined relative to a longitudinal axis (8). [2] Stator (1) according to claim 1, characterized by that the inner contour area (9) is roof-shaped. [3] Stator (1) according to claim 1 or 2, characterized bythat the inner contour region (9) has an axial central section (12) which directly forms a radially innermost region of the slot closure body (6). [4] Stator (1) according to claim 3, characterized by that the inner contour region (9) has two bevel sections (13a, 13b) each axially adjacent to the central section (12), wherein an inner diameter of the bevel sections (13a, 13b) widens with increasing distance from the central section (12). [5] Stator (1) according to one of claims 1 to 4, characterized by that the inclined sections (13a, 13b) have a continuous gradient. [6] Stator (1) according to one of claims 1 to 5, characterized by that the inner contour region (9) protrudes inwards at least in sections beyond the radial inner side (7) of the base body (3). [7] Stator (1) according to one of claims 1 to 6, characterized bythat the inner contour area (9) is axially aligned centrally to the base body (3). [8] Stator (1) according to one of claims 1 to 7, characterized by that the inner contour area (9) is adjoined by side areas (16a, 16b) extending axially parallel to the longitudinal axis (8). [9] 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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