Stator device for an electric machine and electric machine for propelling a vehicle

Abstract

Stator device (1) for an electric machine (101) comprising the following: - a housing (2) with an opening (3) for supplying a coolant from outside the housing (2) to inside the housing (2); - a stator core (5) with a longitudinal axis (6), a first axial end face (7) and a second axial end face (8) opposite the first axial end face (7), wherein the stator core (5) is arranged in the housing (2) and forms the following: (i) a cavity (9) which extends at least partially around the longitudinal axis (6) at an intermediate axial position between the end faces (7, 8), (ii) at least one first through hole (10) extending from the first axial end face (7) to the cavity (9), (iii) several second through holes (11) each extending from the first axial end face (7) to the cavity (9), and (iv) several third through holes (12) extending from the second axial end face (8) to the cavity (9), wherein the first to third through holes (10, 11, 12) are fluid-conductingly connected to the cavity (9); and - an inlet structure (15) configured to supply the coolant from the opening (3) into the at least one first through-hole (10) to form a cooling path (16), wherein the cooling path (16) extends from the opening (3) through the inlet structure (15) and the at least one first through-hole (10) into the cavity (9) and branches off from the cavity (9) into the second through-holes (11) and into the third through-holes (12).

Description

[0001] The present invention relates to a stator device for an electric machine, comprising: a housing having an opening for supplying a coolant from outside the housing to inside the housing;and a stator core having a longitudinal axis, a first axial end face, and a second axial end face opposite the first axial end face, the stator core being disposed in the housing and defining a cavity extending at least partially around the longitudinal axis at an axially intermediate position between the end faces, at least one first through-hole extending from the first axial end face to the cavity, a plurality of second through-holes each extending from the first axial end face to the cavity, and a plurality of third through-holes extending from the second axial end face to the cavity, the first to third through-holes being fluidly connected to the cavity.;

[0002] Furthermore, the present invention relates to an electric machine for propelling a vehicle.

[0003] Stator cores comprising a cavity extending at least partially along a longitudinal axis and at an intermediate position between end faces of the stator core allow the distribution of a coolant at the intermediate position toward both end faces. This allows for a substantially homogeneous distribution of the coolant, compared to the unidirectional supply of the coolant to one end face toward the other end face.

[0004] For example, US 2021 / 0351641 A1 discloses an electric motor cooling system comprising a stator disposed within a motor housing. The stator comprises a first solid stator portion and a second solid stator portion. A plurality of first and second solid axial cooling channels are integrated into the first and second solid stator portions, respectively. A coolant manifold is integrated into the stator and positioned between the first solid stator portion and the second solid stator portion. The coolant manifold fluidly couples an electric motor coolant inlet to the plurality of first and second solid axial cooling channels.

[0005] However, this conventional stator device provides a coolant inlet through a housing for access to the cavity at a position corresponding to the actual intermediate position. Such a radial inlet increases the overall radial dimensions of the stator device, which conflicts with the strict installation space requirements of automotive applications.

[0006] An object of the present invention is to provide an improved possibility for supplying a coolant into a stator core of a stator device, in particular with regard to keeping a radial extension of the stator device small.

[0007] According to the present invention, this object is achieved by a stator device for an electric machine as described above, which further comprises an inlet structure configured to supply the coolant from the opening into the at least one first through-hole to form a cooling path, wherein the cooling path extends from the opening through the inlet structure and the at least one first through-hole into the cavity and branches off from the cavity into the second through-holes and into the third through-holes.

[0008] The stator device for an electric machine according to the invention comprises a housing. The housing has an opening for supplying a coolant from outside the housing to inside the housing.

[0009] The stator device according to the invention further comprises a stator core. The stator core has a longitudinal axis, a first axial end face, and a second axial end face. The second axial end face is opposite the first axial end face. The stator core is arranged in the housing. The stator core forms a cavity. The cavity extends at least partially around the longitudinal axis at an axial intermediate position. The axial intermediate position is located between the end faces. The stator core further forms at least one first through-hole. The at least one first through-hole extends from the first axial end face to the cavity. The stator core further forms a plurality of second through-holes. Each of the second through-holes extends from the first axial end face to the cavity. The stator core further forms a plurality of third through-holes.Each of the third through-holes extends from the second axial end face to the cavity. The first through third through-holes are fluidically connected to the cavity.

[0010] The stator device according to the invention further comprises an inlet structure. The inlet structure is configured to supply the coolant from the opening into the at least one first through-hole to form a cooling path. The cooling path extends from the opening through the inlet structure and the at least one first through-hole into the cavity. The cooling path branches off from the cavity into the second through-holes and the third through-holes.

[0011] The present invention is based on the idea of ​​providing the first and second through-holes extending from the first axial end face to the cavity as in conventional stator devices, but using the at least one first through-hole for supplying the coolant so that it is fed into the cavity. The cavity can act as a distributor for distributing the coolant into the second and third through-holes for cooling the stator core. The inlet structure forms a connection between the opening and the at least one first through-hole on the first axial end face. Advantageously, a space-wasting radial inlet positioned at the axial intermediate position can be omitted since the coolant is supplied from the first axial end face into the stator core.

[0012] In particular, the coolant is a cooling fluid. The coolant is preferably a cooling liquid, e.g., an oil, water, or a cooling agent.

[0013] The stator core may be formed from a plurality of axially stacked metal sheets. Preferably, the metal sheets are electrically insulated from one another. Preferably, the first to third through holes extend parallel or substantially parallel to the longitudinal axis.

[0014] In particular, the cavity extends in the circumferential direction relative to the longitudinal axis. The intermediate position can be an axial position midway between the first and second axial end faces.

[0015] Preferably, the stator device according to the invention further comprises a boundary structure forming a fluid chamber around the longitudinal axis. The fluid chamber can be bounded at least by the boundary structure, the first axial end face, and the housing. In a preferred design, the inlet structure guides the cooling path through the fluid chamber in a liquid-tight manner. The second through-holes can be configured to allow the coolant to exit into the fluid chamber.

[0016] Preferably, the inlet structure and the boundary structure are integrally formed. This allows the boundary structure and the inlet structure to be formed as a single part that can be attached to the stator core in a single manufacturing step.

[0017] Furthermore, the boundary structure can be formed by a circular ring-shaped body attached to the stator core. The boundary structure can thus form a so-called cooling ring.

[0018] According to a highly preferred construction, the confinement structure comprises a plurality of nozzles configured to inject the coolant from the fluid chamber into a radially inner volume confined by the confinement structure on the opposite side of the fluid chamber.

[0019] Furthermore, the stator core of the stator device according to the invention may form slots extending from the first axial end face to the second axial end face, wherein the stator device comprises a stator winding received in slots.

[0020] Advantageously, the nozzles can be configured to spray the coolant onto a winding head formed by the stator winding on the first axial end face. This allows the coolant not only to cool the stator core (and indirectly the stator winding arranged therein) but also to realize spray cooling of the winding head.

[0021] In general, the inlet structure can be formed by a polymer. The boundary structure can be formed by a polymer. The inlet structure and the boundary structure can be made of the same material.

[0022] The stator device may comprise a secondary boundary structure forming a second fluid chamber around the longitudinal axis. The second fluid chamber may be bounded at least by the boundary structure, the first axial end face, and the housing. In a preferred design, the third through-holes are configured to allow the coolant to exit into the second fluid chamber. All statements relating to the first boundary structure apply analogously to the second boundary structure. In particular, the second boundary structure may be provided with nozzles for spraying the coolant onto a winding head formed by the stator winding on the second axial end face.

[0023] The at least one first through-hole and / or the second through-holes and / or the third through-holes may be arranged further outward than the slots in a radial direction.

[0024] The housing may comprise a further opening configured as an outlet for the coolant that has escaped from the second through-holes and / or the third through-holes. In particular, a sump is formed in the housing for collecting the escaped coolant, wherein the sump is fluidly connected to the further opening.

[0025] With regard to the stator device according to the invention, the opening may be located on the far side of the first axial end face when viewed from the second axial end face. The opening may be tubular and extend in an axial direction.

[0026] In particular, the at least one first through-hole and the second through-holes are distributed around the longitudinal axis over the circumference. The third through-holes can be distributed around the longitudinal axis over the circumference accordingly.

[0027] The at least one first through-hole and the second through-holes can have an identical shape. Furthermore, the second through-holes and / or the third through-holes can have an identical shape. The respective through-holes can have a circular, polygonal, or slot-shaped cross-section. Preferably, the cross-section of the respective through-holes is elongated.

[0028] According to a preferred design of the stator device according to the invention, the cavity is formed by a circumferential groove in the outer periphery of the stator core. The cavity may extend annularly around the longitudinal axis, thereby forming a closed annular cavity. Alternatively, the cavity may be separated at a certain angular position.

[0029] More preferably, the groove is closed by the housing in the radial direction. The at least one first through-hole and / or the second through-holes and / or the third through-holes can be connected to the cavity by extending axially into the groove.

[0030] It is further preferred that a first through-hole be provided and connected to the opening by the inlet structure. Alternatively, several, in particular two, three, or four, first through-holes may be provided and connected to the opening by the inlet structure, wherein the inlet structure distributes the coolant from the opening to the first through-holes.

[0031] The above object is further achieved by an electric machine for propelling a vehicle, the electric machine comprising: a stator device according to the invention; and a rotor rotatably mounted in the stator core and supported by the housing.

[0032] The electric machine may be a synchronous machine, which may be electrically excited or permanently excited. Alternatively, the electric machine may be an induction machine. The electric machine may include a shaft that is rotationally fixed to the rotor and extends along the longitudinal axis.

[0033] The vehicle can be a battery-powered vehicle (BEV - Battery-Electric Vehicle) or a hybrid vehicle with an internal combustion engine.

[0034] All statements relating to the stator device according to the invention also apply analogously to the electrical machine according to the invention, so that the above-mentioned advantages of the stator device according to the invention can also be achieved with the electrical machine according to the invention.

[0035] Further details and advantages of the invention are disclosed below. Reference is made to the schematic drawings, which show the following: Fig. 1 is a schematic drawing of an embodiment of the stator device according to the invention; Fig. 2 is a perspective view of the stator core according to the embodiment; Fig. 3 is a perspective view of the stator core with the inlet region and the boundary regions according to the embodiment; Fig. 4 a cut-out partial view of Fig. 3 to represent a coolant flow; and Fig. 5 a schematic drawing of the vehicle and an embodiment of the electric machine according to the invention.

[0036] Fig. 1 is a schematic drawing of an embodiment of a stator device 1.

[0037] The stator device 1 comprises a housing 2 having an opening 3 for supplying a coolant from outside the housing 2 to inside the housing 2. In the present embodiment, the opening is, for example, tubular and extends in an axial direction. Furthermore, Fig. 1 another opening 4, which acts as an outlet for the coolant.

[0038] Fig. 2 is a perspective view of a stator core 5 of the stator device 1 according to the embodiment.

[0039] The stator core 5 has a longitudinal axis 6, a first axial end face 7 and a second axial end face 8, which is opposite the first axial end face 7. The stator core 5 is arranged in the housing 2 (see Fig. 1). On its outer periphery, the stator core 5 forms a cavity 9 that extends around the longitudinal axis at an intermediate position between the axial end faces 7, 8. More precisely, the cavity 9 is a circular, closed space that extends circumferentially around the longitudinal axis 6 at a midpoint between the first and second end faces 7, 8. In the radial direction, the cavity 9 is closed by the housing 2 (see Fig. 1).

[0040] Furthermore, the stator core 5 forms a first through-hole 10 and a plurality of second through-holes 11, each extending from the first axial end face 7 to the cavity 9. Furthermore, the stator core 5 forms third through-holes 12, which extend from the second axial end face 8 to the cavity 9. The first to third through-holes 10, 11, 12 are fluidly connected to the cavity 9.

[0041] In general, the stator core 2 may be formed from a plurality of axially stacked metal sheets that are electrically insulated from each other. More specifically, Fig. 2 a plurality of slots 13 formed in the inner periphery of the stator core 5. The through holes 10, 11, 12 are arranged further outward than the slots 13 in a radial direction and have a substantially elongated cross-sectional shape. The slots 13 accommodate a stator winding, which forms winding heads 14 on both axial end faces 7, 8. For the sake of clarity, the winding heads are shown only schematically.

[0042] Fig. 3 is a perspective view of the stator core 5 with an inlet structure 15 and boundary regions 17, 18 according to the embodiment. Fig. 4 is a cutaway partial view of Fig. 3 to show a coolant flow.

[0043] The stator device 1 further comprises an inlet region 15 configured to direct the coolant from the opening 3 (see Fig. 1) into the first through-hole 10 to form a cooling path 16. As best shown in Fig. 4, the cooling path 16 extends from the opening 3 through the inlet structure 15 and the first through-hole 10 into the cavity 9. From the cavity 9, the cooling path 16 branches off into the second through-holes 11 and the third through-holes 12.

[0044] The first boundary structure 17 forms a fluid chamber around the longitudinal axis 6. The fluid chamber is bounded by the first boundary structure 17, which forms a radially inner boundary, the first axial end face 8, which forms an axial boundary on the stator core side, and the housing 2, which forms an axial boundary opposite the stator core 2. The inlet structure 15 guides the cooling path 16 in a liquid-tight manner through the fluid chamber. When the coolant is fed via the inlet region 15 into the first through-hole 10 and distributed through the cavity 9 into the second through-holes 11, the coolant exits through the second through-holes 11 into the fluid chamber at the first axial end face 7.

[0045] As in Fig. As can be seen in Figure 3, the inlet structure 15 is formed integrally with the first boundary structure 17, which is formed by an annular body attached to the stator core 2. The structures 15, 17 are formed from a polymer and are fixed to the stator core 5 by schematically shown fixing elements 19.

[0046] The first boundary structure 17 comprises a plurality of nozzles 20 configured to inject the coolant from the fluid chamber into a radially inner volume defined by the boundary structure on the opposite side of the fluid chamber. There, the nozzles 20 inject the coolant onto the winding head 14, which is formed by the stator winding on the first axial end face 7.

[0047] The second boundary structure 18 is attached to the second axial end face 8 and corresponds to the first boundary structure 17, with the difference that no inlet structure 15 is provided on the second axial end face 8. When the coolant is supplied via the inlet region 15 into the first through-hole 10 and distributed through the cavity 9 into the third through-holes 12, the coolant exits through the third through-holes 12 into a corresponding fluid chamber on the second axial end face 7. There, the coolant sprays onto the winding head formed on the second axial end face 7.

[0048] According to further embodiments, a plurality of first through-holes 10 are provided, which are supplied by a single or multiple inlet structures 15. Furthermore, according to further embodiments, the through-holes 10, 11, 12 can have different cross-sectional shapes.

[0049] Fig.5 is a schematic diagram of a vehicle 100 and an embodiment of an electric machine 101.

[0050] The electric machine 101 is configured to propel the vehicle 100 and includes a stator device 1 according to one of the embodiments described above and a rotor 102. The rotor 102 is rotatably mounted in the stator core 5 and supported by the housing 2. The electric machine 101 may be a permanently excited or electrically excited synchronous machine or an induction machine.

[0051] The electric vehicle 100 includes wheels 103 that are coupled directly or indirectly, e.g., via a transmission, to the electric machine 101 for rotating the wheels 103. According to the embodiment, the electric vehicle 100 is a battery-electric vehicle (BEV).

[0052] Alternatively, the electric vehicle 100 may additionally include an internal combustion engine, thereby creating a hybrid vehicle. Furthermore, the electric vehicle 100 may include a fuel cell that supplies the stator windings of the stator device 1. 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] US 2021 / 0351641 A1

[0004]

Claims

[1] Stator device (1) for an electrical machine (101), comprising: - a housing (2) with an opening (3) for supplying a coolant from outside the housing (2) to inside the housing (2); and - a stator core (5) having a longitudinal axis (6), a first axial end face (7) and a second axial end face (8) opposite the first axial end face (7), the stator core (5) being arranged in the housing (2) and forming: (i) a cavity (9) extending at least partially around the longitudinal axis (6) at an axial intermediate position between the end faces (7, 8), (ii) at least one first through-hole (10) extending from the first axial end face (7) to the cavity (9), (iii) a plurality of second through-holes (11) each extending from the first axial end face (7) to the cavity (9), and (iv) a plurality of third through holes (12) extending from the second axial end face (8) to the cavity (9), wherein the first to third through holes (10, 11, 12) are fluidly connected to the cavity (9); characterized by - an inlet structure (15) configured to supply the coolant from the opening (3) into the at least one first through-hole (10) to form a cooling path (16), wherein the cooling path (16) extends from the opening (3) through the inlet structure (15) and the at least one first through-hole (10) into the cavity (9) and branches off from the cavity (9) into the second through-holes (11) and into the third through-holes (12). [2] The stator device according to claim 1, further comprising: - a boundary structure (17) forming a fluid chamber around the longitudinal axis (6), wherein the fluid chamber is bounded at least by the boundary structure (17), the first axial end face (7) and the housing (2), wherein the inlet structure (15) guides the cooling path (16) in a liquid-tight manner through the fluid chamber, wherein the second through-holes (11) are configured to allow the coolant to escape into the fluid chamber. [3] Stator device according to claim 2, wherein the inlet structure (15) and the limiting structure (17) are integrally formed. [4] Stator device according to claim 2 or 3, wherein the limiting structure (17) is formed by an annular body attached to the stator core (5). [5] Stator device according to one of claims 2 to 4, wherein the boundary structure (17) comprises a plurality of nozzles (20) configured to inject the coolant from the fluid chamber into a radially inner volume defined by the boundary structure (17) on the opposite side of the fluid chamber. [6] Stator device according to one of the preceding claims, wherein the stator core (2) forms slots (13) extending from the first axial end face (7) to the second axial end face (8), the stator device (1) comprising a stator winding received in slots (13). [7] Stator device according to claim 5 and 6, wherein the nozzles (20) are configured to spray the coolant onto a winding head (14) formed by the stator winding on the first axial end face (7). [8] Stator device according to claim 6 or 7, wherein the at least one first through-hole (10) and / or the second through-holes (11) and / or the third through-holes (12) are arranged further outward than the slots (13) in a radial direction. [9] Stator device according to one of the preceding claims, wherein the opening (3) - is arranged on the more distant side of the first axial end face (7) when viewed from the second axial end face (8) and / or - is tubular and extends in an axial direction. [10] Stator device according to one of the preceding claims, wherein the at least one first through-hole (10) and the second through-holes (11) are distributed around the circumference around the longitudinal axis (6) and / or the third through-holes (12) are distributed around the circumference around the longitudinal axis (6). [11] Stator device according to one of the preceding claims, wherein the at least one first through-hole (10) and the second through-holes (11) have an identical shape and / or the second through-holes (11) and / or the third through-holes (12) have an identical shape. [12] Stator device according to one of the preceding claims, wherein the cavity (9) is formed by a circumferential groove in the outer periphery of the stator core (5), the groove being closed by the housing (2) in the radial direction. [13] Stator device according to claim 12, wherein the at least one first through-hole (10) and / or the second through-holes (11) and / or the third through-holes (12) are connected to the cavity (9) by extending axially into the groove. [14] Stator device according to one of the preceding claims, wherein - a first through-hole (10) is provided and is connected to the opening (3) by the inlet structure (15) or - a plurality of, in particular two, three or four, first through-holes (10) are provided and are connected to the opening (3) by the inlet structure (15), wherein the inlet structure (15) distributes the coolant from the opening (3) to the first through-holes (10). [15] Electric machine (101) for propelling a vehicle (100), the electric machine (101) comprising: - a stator device (1) according to one of the preceding claims; and - a rotor (102) rotatably mounted in the stator core (5) and supported by the housing (2).

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