Stator for an electric machine, electric machine and at least partially electrically drivable motor vehicle
Patent Information
- Application Number
- PCT/DE2026/100139
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-24
- Filing Date
- 2026-02-06
- Publication Date
- 2026-08-27
Smart Images
Figure DE2026100139_27082026_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Stator for an electric machine, electric machine, and at least partially electrically powered motor vehicle
[0003] The present invention relates to a stator for an electric machine of a drive train of a motor vehicle that is at least partially electrically powered, wherein the stator is hollow cylindrical and has an annular yoke. A stator winding is provided on the inside of the yoke, the stator winding comprising a winding head facing the gearbox and an opposing winding head facing away from the gearbox, and wherein a casing is provided on the outside of the yoke.
[0004] Furthermore, the present invention relates to an electric machine, in particular for a motor vehicle that is at least partially electrically powered, comprising the above stator and a rotor.
[0005] Furthermore, the invention relates to a motor vehicle that is at least partially electrically powered, with the above stator in the drive train, or with the above electric machine in the drive train.
[0006] A stator for an electric machine is a generally known design. In known stators, for example, the stator shell is cooled by liquid cooling using coolants such as water-glycol mixtures or, if applicable, oil-based coolants. However, cooling within the stator shell increases the required installation space, which, especially with the extensive use of aluminum in the housing, leads to an increase in the weight of the electric machine.
[0007] Furthermore, the effectiveness of such cooling is low because the stator teeth, which actually need to be cooled, are located far from the coolant, and heat conduction and / or heat spreading is not optimal. Additionally, the stator winding heads are not engaged with the casing and are therefore only cooled indirectly via the stator, resulting in poor cooling.
[0008] This leads to local thermal peaks, which are detrimental to the stator winding material, particularly in the winding heads and their insulation, and consequently have a negative impact on its service life. Furthermore, the electric machine suffers performance losses when the temperature in the winding head, and thus the resistance, increases, due in part to a higher current demand.
[0009] Known stators with a cooling device therefore still have potential for improvement.
[0010] The object of the present invention is to overcome at least one disadvantage of the prior art, at least partially. In particular, it is an object of the present invention to provide a stator for an electric machine that is cooled more effectively, especially at the winding head and / or winding heads. Furthermore, it is an object of the present invention to provide a stator for an electric machine that can exhibit improved performance.
[0011] The solution of the present invention is achieved by a stator for an electric machine of a drive train of a motor vehicle that is at least partially electrically driven, comprising the features of claim 1, an electric machine according to claim 11, and a motor vehicle that is at least partially electrically driven according to claim 12. Preferred embodiments of the invention are described in the dependent claims, in the description, and / or the figures, wherein further features described or shown in the dependent claims, in the description, or in the figures may, individually or in any combination, constitute an object of the invention unless the context clearly indicates otherwise.
[0012] According to the invention, a stator for an electric machine of a drive train of a motor vehicle that is at least partially electrically driven is provided, wherein the stator is hollow cylindrical and has an annular yoke, wherein a stator winding is provided on the inside of the yoke, the stator winding comprises a winding head facing the gearbox and an opposing winding head facing away from the gearbox, wherein a shell housing is provided on the outside of the yoke, wherein the stator comprises a cooling device that expands a hydraulic volume between the yoke and the shell housing in such a way that a cooling medium from the hydraulic volume can be applied to the winding head facing the gearbox and / or facing away from the gearbox.One aspect of the invention is that the cooling device does not merely consist of the hydraulic volume between the yoke and the casing, but is designed such that the cooling medium can be applied from this hydraulic volume to the winding heads facing the gearbox and / or away from the gearbox. In other words, cooling medium is brought to the winding heads via the cooling device in order to dissipate the heat generated there. This results in direct cooling of the stator winding heads, which significantly increases the cooling capacity and, consequently, the performance of the electric machine.
[0013] The cooling medium is preferably a fluid. The cooling medium is further preferably an oil, a water-glycol mixture, and / or a synthetic coolant.
[0014] Regarding the application of the cooling medium to the winding head, a preferred embodiment of the invention provides that the cooling device comprises a cooling tube, and that the cooling tube for applying the cooling medium to the winding head facing the gearbox and / or the gearbox-remote side includes a circularly extending section arranged on the inside of the winding head, which has radially outwardly directed bores. Accordingly, the cooling medium guided through the circular section is preferably applied to the winding head via the bores. Due to the position of the circular section on the inside of the winding head and the position of the bores on the radial outside of the circular section, the cooling medium is preferably applied radially from the inside out onto the side of the winding head facing away from the yoke.
[0015] The circular section of the cooling tube is preferably arranged at a defined distance to the winding head, preferably 4 mm ± 10%, and preferably has a defined hydraulic cross-section, preferably 20 mm. 2 ± 10%, and further preferably a defined wall thickness of preferably 1.5 mm ± 10%. The bores in the circular section preferably have a diameter of 1.5 mm ± 10%.
[0016] In principle, it is possible to use the cooling pipe with the circular section for cooling both the winding head facing the gearbox and the winding head facing away from the gearbox. According to a preferred embodiment of the invention, the circularly extending section is arranged on the winding head facing the gearbox, and the stator comprises an annular housing plate connected to the outer casing and the yoke, and arranged on the side facing the gearbox. This allows for easy attachment of the circular section, particularly at a defined distance from the winding head facing the gearbox, via the housing plate. Since the housing plate is also connected to the outer casing and the yoke, it also provides a simple connection to the hydraulic volume between the yoke and the outer casing.Furthermore, it is possible that the housing plate is designed as a monolithic component with a gearbox housing. In this case, the gearbox housing would be used directly as the counterpart.
[0017] In this context, according to a further preferred embodiment of the invention, the cooling pipe for connecting the circular section to the hydraulic volume comprises a bridge-like connecting piece that extends at least partially into the housing plate. The circular section is thus preferably connected to the hydraulic volume by means of the bridge-like connecting piece, which is preferably designed as a bridge-shaped pipe section. To seal the cooling medium against the housing plate, an O-ring is preferably provided at the end of the connecting piece.
[0018] Regarding the attachment of the circular section, a further preferred embodiment of the invention provides that the circularly extending section of the cooling tube is fixed to the housing plate via mounting lugs. Preferably, several mounting lugs, for example three, are used to enable the circular section to be fixed to the housing plate. A connection between the circular section and the housing plate is particularly preferred to prevent displacement under pressure and vibration during operation of the electric machine. It is further preferred that the mounting lugs are pressed into recesses in the housing plate. Preferably, the mounting lugs are fitted with O-rings at the connection points to compensate for tolerances between the housing plate, preferably made of aluminum, and the mounting lug.According to a preferred embodiment of the invention, the circular section of the cooling tube, the bridge-like connecting piece, and the mounting brackets are manufactured in one piece. This allows for a particularly robust design.
[0019] According to a preferred embodiment of the invention, the cooling pipe, the circular section, the bridge-like connecting piece and / or the mounting brackets are made of a plastic material.
[0020] Particularly preferred are the circular section, the bridge-like connecting piece and the mounting brackets made of a plastic material and further preferably manufactured as a monolithic component using a plastic printing process or plastic injection molding process.
[0021] With regard to the housing plate, a further preferred embodiment of the invention provides that the annular housing plate comprises bores extending through to the hydraulic volume on its inner side, such that cooling medium from the hydraulic volume can be applied to the outer surface of the winding head facing the gearbox. In other words, it is preferably provided that the housing plate also has bores through which the cooling medium can be applied to the winding head. In this way, areas of the winding head that cannot be covered by the inner circular section due to space constraints can be cooled from the outer diameter. The bores in the housing plate preferably have a defined length of preferably 4 mm ± 10%. More preferably, the bores have the same geometry as the bores in the circular section.
[0022] With respect to the side facing away from the gearbox, a further preferred embodiment of the invention provides that the stator comprises a housing cover connected to the outer casing and the yoke and arranged on the side facing away from the gearbox. The housing cover includes through bores extending to the hydraulic volume, preferably axial and / or radial bores, such that cooling medium from the hydraulic volume can be applied to the outside of the winding head facing away from the gearbox. Thus, analogous to the housing plate, it is preferably provided that the housing cover, which is arranged facing away from the gearbox, also includes bores for distributing the cooling medium onto the winding head facing away from the gearbox.With regard to the bores in the circular section, the housing plate, and / or the housing cover, it is preferably provided, as already mentioned, that these bores distribute the cooling medium radially either from the inside out onto the inside of the winding head, as in the case of the circular section, or from the outside in onto the outside of the winding head, as in the case of the housing plate and the housing cover. The bores are therefore preferably provided on an outer circumference (in the case of the circular section) or on an inner circumference (in the case of the housing plate and the housing cover).
[0023] Regarding the distribution of the bores around the circumference, it can be ensured that the bores are evenly distributed. This also ensures a uniform application of coolant to the winding head around the entire circumference of the stator.
[0024] According to a preferred embodiment of the invention, the bores are not evenly distributed around the circumference. Preferably, the bores are arranged more frequently on the half of the circumference furthest from gravity. Thus, during operation of the electric machine, the cooling medium, driven by gravity, runs / drips to other locations on the winding head. This enables efficient cooling, as the cooling medium can drip downwards along the turns of the stator winding and thus cover further areas.
[0025] The injection holes in the circular section of the cooling tube are arranged, for example, such that the majority of the holes, preferably 12 ± 3, are located on the side of the winding head facing away from gravity during machine operation and point radially towards the winding head. Furthermore, preferably, the circular section of the cooling tube, in the configuration with unevenly distributed holes, has an additional drain hole on the side facing gravity to allow residual cooling medium to drain out when the machine is at rest.
[0026] In a further preferred embodiment, the housing cover is provided to include through bores extending to the hydraulic volume, such that cooling medium can be applied axially from the hydraulic volume to the winding head facing away from the gearbox. These bores can also be distributed evenly or unevenly around the circumference. In the case of an uneven distribution, the bores are also arranged more frequently on the half of the circumference facing away from gravity.
[0027] Further technical features, effects and advantages of the stator will become apparent to the person skilled in the art from the following description of the electric machine, the at least partially electrically powered motor vehicle and the exemplary embodiments in the description of the figures.
[0028] As already mentioned, the invention also relates to an electric machine, in particular for a motor vehicle that is at least partially electrically powered, comprising the stator and rotor described above. The rotor is preferably arranged on a shaft inside a hollow cylindrical stator. The electric machine can be designed as a permanent magnet synchronous machine. Alternatively, the electric machine can be designed as a separately excited synchronous machine. Furthermore, it is possible that the electric machine is a reluctance motor.
[0029] Furthermore, the invention relates to a motor vehicle that is at least partially electrically powered, comprising an arrangement of a rotor and the stator described above.
[0030] The use of the stator according to the invention in electric machines can contribute, in particular, to efficient cooling of a drive train in at least partially electrically powered motor vehicles. As a result, the electric machine exhibits reduced current consumption, especially under high loads. Furthermore, the service life of the electric machine can be increased by using the stator.
[0031] The invention is further explained below with reference to the figures, whereby one or more features of the figures, individually or in combination, can constitute a feature of the invention. Furthermore, the figures are to be considered merely exemplary and in no way limiting.
[0032] Fig. 1 schematically shows a sectional view through an electric machine with a stator according to a preferred embodiment of the invention. Fig. 2 schematically shows a perspective detail view of a cooling tube of the stator from Figure 1.
[0033] Fig. 3 schematically shows a perspective detail view of a housing plate of the stator from Figure 1, and
[0034] Fig. 4 schematically shows a perspective detail view of a housing cover of the stator from Figure 1.
[0035] Figure 1 schematically shows a sectional view through an electric machine 10 with a stator 12 according to a preferred embodiment of the invention. Figures 2 to 4 each show corresponding perspective detail views of components of the stator 12 from Figure 1, which will be discussed in more detail later in this description.
[0036] The electric machine 10 in Figure 1 comprises a stator 12 and a rotor 14. The rotor 14 is arranged on a shaft 16 inside a hollow cylindrical stator 12. The stator 12 has an annular yoke 18. The yoke 12 is typically formed by a plurality of ring-shaped stamped laminations arranged one behind the other in the axial direction 20 and connected to each other. A stator winding 24 is provided on a radially inward-facing side 22 of the yoke 12. The stator winding 24 comprises a winding head 26 facing the gearbox and a winding head 28 axially opposite and facing away from the gearbox. A casing 30 is provided on the outside of the yoke.For cooling the stator 12 and in particular the winding heads 26, 28, it is provided that a cooling device 32 expands a hydraulic volume 34 between the yoke 18 and the shell housing 30 in such a way that a cooling medium from the hydraulic volume 34 can be applied to the winding head 26, 28 facing the gearbox and / or facing away from the gearbox.
[0037] As can be seen in Figures 1 and 2, the cooling device 32 has a cooling pipe 36 for applying the cooling medium. The cooling pipe 36 has a circularly extending section 38, which in this case extends on the inside of the winding head 26 facing the gearbox. The section 38 has radially outwardly directed bores 40 for applying the cooling medium to the winding head. The cooling pipe 36 is arranged in this case at a defined distance of 4 mm from the winding head 26 and has a defined hydraulic cross-section of 20 mm². 2The wall thickness of the cooling pipe 36 is 1.5 mm, and the cooling pipe 36 is made of plastic. The circular section 38 of the cooling pipe 36 is connected to the hydraulic volume 34 between the casing 30 and the yoke 18 by means of a bridge-like connecting piece 42.
[0038] The bores 40, which function as injection holes, have a diameter of 1.5 mm and are arranged relative to the circumference of the circular section 38 such that the majority – in this case 12 – of the bores 40 are located on the side of the winding head 26 facing away from gravity during operation in the electric machine 10. The direction of gravity is symbolized by an arrow FG in Figures 1 to 4. The bores 40 point radially towards the winding head 26.
[0039] In this case, boreholes 40 are provided in a section of the arc between 8 and 4 o'clock, with the direction of gravity FG defined from 12 o'clock to 6 o'clock. The boreholes in this segment are spaced 15° apart. To allow residual cooling medium to drain when the system is stationary, an additional borehole 40' is provided at 6 o'clock.
[0040] In the present embodiment, the cooling tube 36 is connected to a housing plate 46 of the stator 12 by means of several attached mounting brackets 44 and fixed there to prevent displacement under pressure load and oscillation during operation of the electric machine 10.
[0041] For assembly, the webs 44 are fitted with O-rings 48 and pressed into the housing plate 46. To seal the cooling medium against the housing plate 46, another O-ring 48' is attached to the end of the bridge-like connecting piece 42.
[0042] In summary, the present design provides that the circularly extending section 38 is arranged on the winding head 26 facing the gearbox, and the stator 12 comprises the annular housing plate 46, which is connected to the outer casing 30 and the yoke 18 and is arranged on the side facing the gearbox. The housing plate 46 is also part of the cooling device 32 and is shown in Figure 3. For cooling the winding head 26, the housing plate 46 has through bores 50 extending on its inner side to the hydraulic volume 34. The cooling medium from the hydraulic volume 34 can be applied to the outside of the winding head 26 facing the gearbox through the bores 50, which act as injection holes. The bores 50 have a defined length of 4 mm and, like the bores 40 on the circular section 38, are located on the side of the winding head 26 facing away from gravity.
[0043] The present embodiment, as shown particularly in Figures 1 and 4, further demonstrates that a housing cover 52 is used as the starting point for the distribution of the cooling medium. The stator 12 has the housing cover 52, which is connected to the outer casing 30 and the yoke 18 and is located on the side facing away from the gearbox. The housing cover 52 has further bores 54 extending to the hydraulic volume 34, which are designed such that cooling medium can be applied axially 20 from the hydraulic volume 34 to the winding head 28 facing away from the gearbox. The positioning of the bores 54 is analogous to the circular section 38 described above. Furthermore, radially oriented bores 54' are provided in the housing cover 52, which are directed towards the outer diameter of the winding head 28.Here too, these bores 54' are particularly advantageous on the side facing away from gravity, analogous to the circular section 38 described above, as the cooling medium can then drip downwards along the windings and cover further areas. Figures 1 and 4 also show that the housing cover 52 has a drain 56 through which the cooling medium distributed by the cooling device 32 onto the winding heads 26, 28 can be removed. Reference numeral list.
[0044] 10 electric machine
[0045] 12 Stator
[0046] 14 Rotor
[0047] 16 wave
[0048] 18 yoke
[0049] 20 axial direction
[0050] 22 radial direction
[0051] 24 Stator windings
[0052] 26 gear-facing winding head
[0053] 28 winding head opposite gear
[0054] 30 casings
[0055] 32 Cooling device
[0056] 34 Hydraulic volume between yoke and jacket housing 36 Cooling pipe
[0057] 38 circular section
[0058] 40 boreholes on the circular section
[0059] 42 bridge-like connecting piece
[0060] 44 Mounting platform
[0061] 46 Housing plate
[0062] 48 O-ring
[0063] 50 holes on housing plate
[0064] 52 Case covers
[0065] 54 holes on the housing cover
[0066] 56 Procedure
[0067] FG direction of gravity
Claims
Patent claims 1. Stator (12) for an electric machine (10) of a drive train of a motor vehicle that is at least partially electrically powered, wherein the stator (12) is designed in a hollow cylindrical shape and has an annular yoke (18), wherein a stator winding (24) is provided on the inside of the yoke, the stator winding (24) comprises a winding head (26) facing the gearbox and an opposing winding head (28) facing away from the gearbox, and wherein a jacket housing (30) is provided on the outside of the jocha, dadu rc hgekennt that the stator (12) includes a cooling device (32) which expands a hydraulic volume (34) between the yoke (18) and the shell housing (30) in such a way that a cooling medium from the hydraulic volume (34) can be applied to the winding head (26, 28) facing the gearbox and / or the gearbox away from the gearbox.
2. Stator (12) according to claim 1, wherein the cooling device (32) comprises a cooling tube (36) and the cooling tube (36) for applying the cooling medium to the winding head (26, 28) facing the gear and / or the winding head away from the gear comprises a circularly extending section (38) arranged on the inside of the winding head (26, 28) which has radially outwardly directed bores (40).
3. Stator (12) according to claim 2, wherein the circularly extending section (38) is arranged on the winding head (26) facing the gearbox and the stator (12) comprises an annular housing plate (46) connected to the shell housing (30) and the yoke (18) and arranged on the side facing the gearbox.
4. Stator (12) according to claim 3, wherein the cooling tube (36) for connecting the circular section (38) with the hydraulic volume (34) comprises a bridge-like connecting piece (42) which extends at least partially into the housing plate (46).
5. Stator (12) according to claim 3 or 4, wherein the circularly extending section (38) of the cooling tube (36) is fixed to the housing plate (46) via mounting tabs (44).
6. Stator (12) according to claims 4 and 5, wherein the circular section (38) of the cooling tube (36), the bridge-like connecting piece (42) and the mounting tabs (44) are manufactured in one piece.
7. Stator (12) according to one of claims 2 to 6, wherein the cooling tube (36), the circular section (38), the bridge-like connecting piece (42) and / or the mounting webs (44) are made of a plastic material.
8. Stator (12) according to one of claims 3 to 7, wherein the annular housing plate (46) comprises bores (50) extending through to the hydraulic volume (34) on the inside such that cooling medium from the hydraulic volume (34) can be applied to the outside of the winding head (26) facing the gearbox.
9. Stator (12) according to one of the preceding claims, wherein the stator (12) comprises a housing cover (52) connected to the shell housing (30) and the yoke (18) and arranged on the side facing away from the gearbox, wherein the housing cover (52) comprises bores (54) extending to the hydraulic volume (34) such that cooling medium from the hydraulic volume (34) can be applied to the outside of the winding head (28) facing away from the gearbox and / or such that cooling medium from the hydraulic volume (34) can be applied axially to the winding head (28) facing away from the gearbox.
10. Stator (12) according to one of claims 2, 8 or 9, wherein the bores (40, 50, 54) are not evenly distributed over the circumference and / or wherein the bores (40, 50, 54) are arranged more frequently on the half of the circumference away from gravity.
11. Electric machine (10) in particular for a motor vehicle which is at least partially electrically powered, comprising a stator (12) according to one of claims 1 to 10 and a rotor (14).
12. At least partially electrically powered motor vehicle with a stator (12) in the drive train, wherein the stator (12) is configured according to one of claims 1 to 10, or with an electric machine (10) in the drive train, wherein the electric machine (10) is configured according to claim 11.