Electric machine having a diverter device for hydraulic medium for end winding cooling in a laminated core of a stator
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- SCHAEFFLER TECHNOLOGIES AG & CO KG
- Filing Date
- 2024-08-16
- Publication Date
- 2026-07-08
Smart Images
Figure DE2024100738_06032025_PF_FP_ABST
Abstract
Description
[0001] Electrical machine with diverter device for hydraulic fluid for winding head cooling in a laminated core of a stator
[0002] The invention relates to an electrical machine, preferably a drive machine, for a motor vehicle, such as a car, truck, bus or other commercial vehicle, with a stator of overall annular design, wherein the stator further comprises a base body consisting of a laminated core and the base body is provided with axially extending, radially inwardly open stator slots and axial cooling channels positioned radially outside the stator slots and / or in the circumferential direction between the stator slots.
[0003] Stators of this type for electrical machines are known, for example, from DE 10 2019 216 134 A1 or US 2022 / 0200370 A1. Stator designs made of stacked laminations / lamination stacks with integrated cooling channels are already well known.
[0004] In the previously known designs, it has been found that relatively complex housing components are required for the complete cooling of the stator, especially of a winding head of a stator coil arranged on an axial side of the base body. Furthermore, these measures usually require a relatively large amount of axial space.
[0005] It is therefore an object of the present invention to provide a stator that is cooled as efficiently as possible and at the same time has compact dimensions.
[0006] This is achieved according to the invention in that a diverter device comprising at least one metal sheet and designed to divert a hydraulic fluid flowing through the cooling channels during operation is attached to one end face of the base body, wherein at least two cooling channels are connected to a common outlet opening of the diverter device. By forming the diverter device from a metal sheet, it is designed on the base body in the most space-saving manner possible without significantly increasing its axial installation space. By bundling two hydraulic fluid flows from two cooling channels towards an outlet opening, a relatively strong jet is generated during operation, which efficiently cools the winding head.
[0007] Further advantageous embodiments are claimed in the subclaims and explained in more detail below.
[0008] Accordingly, it is also advantageous if the diverter device comprises several, preferably at least two or at least three, metal sheets that are arranged axially overlapping / stacked relative to one another and secured to one another. This allows for the easy production of a channel structure within the diverter device between the cooling channels and the outlet opening on the output side. In particular, common processes such as stamping and / or forming processes can be used to manufacture the metal sheets. This significantly simplifies production.
[0009] Furthermore, it has proven advantageous if the at least one metal sheet has a coating which is designed such that, during the manufacturing process of the base body, when the base body is heated to a specific temperature, it is directly bonded to the base body and / or to other metal sheets in a material-to-material / adhesive manner. The at least one metal sheet is thus skillfully baked to the base body. Alternatively or additionally, it is advantageous if the at least one metal sheet forms a positive and / or non-positive connection with the base body. Preferably, the at least one metal sheet has one or more axially projecting pins which engage positively in one or more receiving holes in the base body. As a result, the metal sheet is supported even more robustly on the base body in the radial and circumferential directions.It has also proven advantageous if a first metal sheet of the air guide device forms a collecting channel that overlaps two axial channel openings of two cooling channels (and thus directly connects the cooling channels). This connects the outlet opening to the cooling channels as directly as possible.
[0010] In this regard, it is furthermore expedient if the collecting channel is designed as an axial through-hole, preferably by punching, or as a formed / flared diverting pocket (as a depression / trough) by forming, preferably by stamping. This results in the most cost-effective production of the diverting device.
[0011] The collecting channel is preferably kidney-shaped, U-shaped or V-shaped, which makes it easy to manufacture.
[0012] Furthermore, it is advantageous if the multiple metal sheets of the diverter device have different material thicknesses. This makes it possible to skillfully adapt the flow cross-section of the cooling channels.
[0013] The diversion device is designed even more simply if the collecting channel is connected to the outlet opening formed directly in the first metal sheet or in a second metal sheet connected to the first metal sheet.
[0014] Depending on the existing periphery, it is advantageous if the outlet opening is aligned exclusively axially, i.e. an orifice region of the outlet opening emerges exclusively axially to the surroundings of the diverter device, or is inserted in an axially flared diverter region of a metal sheet in such a way that it / the orifice region is at least partially inclined inwards in a radial direction.
[0015] If at least one metal sheet has a consistent radial inner diameter, it is particularly easy to manufacture. Furthermore, the induction fields / magnetic field lines generated in the base body during operation are influenced as little as possible by the diverter device.
[0016] Alternatively, it is also advantageous if the at least one metal sheet has a radially inwardly projecting support web for each stator tooth of the base body, which support web rests against the stator tooth of the base body. A stator tooth is formed directly between two adjacent stator slots of the base body. The support web is preferably smaller than the stator tooth, so that it only slightly influences the generated magnetic field lines. Alternatively, however, it is also advantageous if the support web has the same shape as the stator tooth and thus completely overlaps / covers it.
[0017] In this regard, it has again proven expedient if the at least one metal sheet is provided with a collecting channel, and the collecting channel has two radially extending sub-regions spaced apart from one another in the circumferential direction and incorporated into different support webs. The support webs provided with the sub-regions are designed with different widths toward the sides of the sub-regions. This also ensures that the induction fields / magnetic field lines generated in the base body during operation are influenced as minimally as possible by the diverter device.
[0018] The respective metal sheet can run continuously in the circumferential direction and thus be ring-shaped or alternatively be composed of several sub-segments, which in turn form a ring-shaped structure.
[0019] The invention will now be explained in more detail below with reference to figures, in which context different embodiments are also shown.
[0020] Shown are: Fig. 1 a perspective view of a longitudinally sectioned stator of an electrical machine according to the invention according to a first embodiment, wherein a diverting device attached to the end face of a base body of the stator is illustrated in the region of a collecting channel, which is connected on the one hand to two cooling channels of a base body and on the other hand to an outlet opening of the diverting device,
[0021] Fig. 2 is a perspective view of a peripheral area of the stator from Fig.
[0022] 1 , illustrating the extension of the diverter device in the circumferential direction and several outlet openings incorporated therein,
[0023] Fig. 3 is a perspective view of the base body of the stator from Fig. 1, illustrating several cooling channels introduced into the base body radially outside of stator slots,
[0024] Fig. 4 is a perspective view of a first metal sheet of the diverter device in the region of a collecting channel formed therein,
[0025] Fig. 5 is a perspective view of a peripheral region of a stator of an electrical machine according to the invention according to a second embodiment, which differs from the first embodiment in particular in that the metal sheets of the diverter device are now provided with support webs, each of which covers a stator tooth of the stator,
[0026] Fig. 6 is a perspective view of a peripheral region of a stator of an electrical machine according to the invention according to a third embodiment, wherein the diverting device is formed by a single metal sheet and the collecting channels formed therein are formed by pronounced diverting pockets,
[0027] Fig. 7 is a perspective view of a stator of an electrical machine according to the invention according to a fourth embodiment, which is implemented similarly to the embodiment of Fig. 6, wherein the outlet openings of the diverter device are also directed radially inwards,
[0028] Fig. 8 is a perspective view of the metal sheet used in Fig. 7 in the area of a diverting pocket to an inner side facing the base body, wherein at the same time a flow of the hydraulic medium taking place during operation can be seen,
[0029] Fig. 9 is a perspective view of a peripheral region of a stator of an electrical machine according to the invention according to a fifth exemplary embodiment, which differs from the first exemplary embodiment in particular in that the outlet openings are arranged in a partially formed region and are thus also aligned in the radial direction,
[0030] Fig. 10 is a perspective view of a collecting channel incorporated in a first metal sheet of Fig. 9, again illustrating the hydraulic fluid flow taking place during operation,
[0031] Fig. 11 is a perspective view of a stator of a stator of an electrical machine according to the invention according to a sixth embodiment, wherein the diverting device is composed of arc-segment-shaped components,
[0032] Fig. 12 is a perspective view of a metal sheet according to a stator of an electrical machine according to the invention according to a seventh embodiment, wherein a pin for fixing the metal sheet to the base body can be seen,
[0033] Fig. 13 is a perspective view of a peripheral region of a stator of an electrical machine according to the invention according to an eighth embodiment, wherein it can be seen that the metal sheets of the diverter device have different sheet thicknesses, Fig. 14 is a perspective view of the stator with the second metal sheet of the diverter device hidden, so that U-shaped collecting channels of a first metal sheet of the diverter device can be clearly seen,
[0034] Fig. 15 is a perspective view of the main body of the stator according to Fig. 13, and
[0035] Fig. 16 is a plan view of the first metal sheet used in Figs. 13 to 15, wherein respective distances between partial areas of the U-shaped collecting channel and the edges of the support webs / stator teeth are shown.
[0036] The figures are merely schematic in nature and serve exclusively to understand the invention. The same elements are provided with the same reference numerals. Furthermore, the features of the various embodiments can, in principle, be freely combined with one another.
[0037] The invention relates to an electric machine 1, as is preferably used for driving a motor vehicle. For the sake of clarity, only the annular stator 2 of the electric machine 1 is shown in Figures 1 to 16.
[0038] The embodiment shown in Fig. 11 shows the stator 2 from its base body 4. The base body 4 is in turn formed from a laminated core 3. This laminated core 3 is composed of a plurality of axially stacked individual laminations designed as identical parts.
[0039] A plurality of stator slots 5 distributed in the circumferential direction are formed in the stator 2 / the base body 4, extending over the entire length of the stator 2. The stator slots 5 of the base body 4 are open radially inward, but can in principle be closed during operation after inserting a coil winding of the stator 2. The stator slots 5 are each delimited from one another in the circumferential direction by radially inwardly projecting stator teeth 16 of the base body 4.
[0040] Based on Fig. 11, to complete the stator 2, additional coil windings are introduced in the usual way, not shown here for the sake of clarity, which run through the stator slots 5. In the usual way, the coil winding then protrudes from the base body 4 by a certain distance on both axial sides and is deflected in these areas, forming a winding head on each side.
[0041] With reference to the first embodiment of Figures 1 to 4, several cooling channels 6 penetrating the base body 4 in the axial direction can be seen in Figure 3 for cooling the stator 2. In this embodiment, one cooling channel 6 is provided for each stator tooth 16, and these are arranged radially outside the stator slots 5 in the base body 4.
[0042] According to the invention, a diverting device 9 according to the invention is attached axially to the base body 4, i.e., to an end face 7 of the base body 4. This diverting device 9 according to the invention is formed entirely from metal sheets 8; 8a, 8b, 8c, in the first exemplary embodiment by three metal sheets 8; 8a, 8b, 8c. The metal sheets 8; 8a, 8b, 8c are designed as electrical sheets and are preferably provided with a special coating before being connected to the base body 4. During the manufacture of the base body 4, the metal sheets 8; 8a, 8b, 8c are directly baked to one another and to the base body 4 by this coating, i.e., they are heated and bonded in a materially bonding / adhesive manner.
[0043] In this context, it should be noted that it is in principle also possible to provide further fastening means, such as form-fitting or force-fitting fastening means. As can be seen in the exemplary embodiment in Fig. 12, it is possible, for example, to attach an axially projecting pin 19 to a metal sheet 8, which is inserted into an oppositely directed receiving opening in the base body 4 and thus serves for radial and circumferential support. For the sake of completeness, it should be noted that the directional specifications used in the present invention, axial / axial direction, radial / radial direction and circumferential direction, are to be understood with reference to a central longitudinal axis 20 of the stator 2, as shown in Fig. 11. A longitudinal axis 20 is to be understood as an axis of rotation of a rotor of the electrical machine 1 that is rotatably mounted within the stator 2 during operation.Axial / axial direction is thus a direction along / parallel to the longitudinal axis 20, radial / radial direction means a direction perpendicular to the longitudinal axis 20 and circumferential direction means a direction along a circular line coaxially encircling the longitudinal axis 20.
[0044] In the first embodiment of Figs. 1 to 4, a first metal sheet 8a of the diverter device 9, which is attached to / rests directly on the base body 4, has the collecting channel 12 shown in Fig. 4. The collecting channel 12 is essentially kidney-shaped. The collecting channel 12 is formed as an axial through-hole 13 in the first metal sheet 8a. On the one hand, the collecting channel 12 is connected to two cooling channels 6 simultaneously. On the other hand, the collecting channel 12 is connected to a common outlet opening 10 of the diverter device 9. The outlet opening 10 is in turn incorporated in a second metal sheet 8b of the diverter device 9 and can be seen in Figs. 1 and 2. Thus, each collecting channel 12 is connected to two cooling channels 6, namely two axial channel openings 11 of two cooling channels 6, and connects these to a common single outlet opening 10, which here is oriented as a simple axial bore.
[0045] In this embodiment, a third metal sheet 8c is also present in the diverter device 9, which here is designed identically to the first metal sheet 8a. The first metal sheet 8a and the third metal sheet 8c lie directly on top of one another; the second metal sheet 8b, in turn, lies directly on the third metal sheet 8c. In this regard, it should be noted that it is also possible to provide a different number of metal sheets 8. As can be seen in the following exemplary embodiments, the diverter device 9 can also be equipped with just a single or two metal sheets 8. The hydraulic fluid flowing out of two cooling channels 6 during operation is thus bundled by the collecting channel 12 and finally passed axially to the environment from the common outlet opening 10.Since, in an assembled state of the stator 2, the winding head is directly axially adjacent to the outlet opening 10, the respective outlet opening 10 also serves to flow around / spray the winding head and thus to cool it.
[0046] Finally, Fig. 2 also shows that the diverting device 9 is designed as a whole in a ring shape. Preferably, the diverting device 9 extends continuously, so that the metal sheets 8; 8a, 8b, 8c are also each implemented as one-piece rings. However, it is also possible, as shown in the embodiment in Fig. 11, to assemble the diverting device 9 from several arcuate segments, which together form an annular structure. Here, there are three annular segments, each of which has the structure of the diverting device 9 with several (also arcuate segment-shaped) metal sheets 8.
[0047] Fig. 5 also shows that the diverter device 9 and thus the metal sheets 8a, 8b, 8c do not necessarily have to have a constant radial inner diameter, as implemented in the first exemplary embodiment. The metal sheets 8a, 8b, 8c can also each have a plurality of radially projecting support webs 17. The support webs 17 are arranged at the same circumferential positions as the stator teeth 16 and are arranged congruently with the stator teeth 16. For each stator tooth 16, a support web 17 is provided for each metal sheet 8a, 8b, 8c. The support webs 17 of the metal sheets 8a, 8b, 8c, each assigned to a stator tooth 16, are arranged congruently with one another and have the same dimensions. The support webs 17 of the metal sheets 8a, 8b, 8c assigned to a stator tooth 16 lie (in the circumferential direction) centrally on the stator tooth 16. In this regard, it should also be noted that according to the embodiment of Figs.13 to 15 it is also possible in principle to design the support webs 17 in the same way as the stator teeth 16 (in cross section).
[0048] In Fig. 6, the diverter device 9 comprises only a single metal sheet 8, which directly forms the collecting channels 12 in the form of stamped diverter pockets 14. The collecting channels 12 are each kidney-shaped or V-shaped. Thus, it is also possible in principle to use a single metal sheet 8 and dispense with the stamped design of the collecting channel 12, which was still implemented in the first embodiment of Figs. 1 to 4.
[0049] Figs. 7 and 8 further illustrate an embodiment in which the outlet opening 10 is arranged on a locally exposed raised area 15 of the metal sheet 8, namely, centrally in the circumferential direction on the diverting pocket 14. The outlet opening 10 is specifically arranged on a radially inclined wall / flank 21 of the raised area 15, so that it also has a specific orientation in the radially inward direction.
[0050] Fig. 8 shows a flow of hydraulic fluid from the cooling channels 6 into the collecting channel 12 and its deflection towards the common outlet opening 10 during operation.
[0051] In the embodiment of Figures 9 and 10 it can again be seen that, on the basis of the first embodiment, it is also possible to radially obliquely position the outlet openings 10 in the second metal sheet by means of local raised areas 15.
[0052] In the embodiment of Fig. 12, the pin 19 is present on an inner side of the metal sheet 8 facing the base body 4 in the assembled state. According to this embodiment, the diverter device 9 preferably comprises only a single metal sheet 8. With regard to both Figures 11 and 12, it should also be noted that these preferably comprise a plastic plate 22 instead of the metal sheet 8. This allows the pins 19 of Fig. 12 to be formed as easily as possible.
[0053] In the embodiment of Figs. 13 to 16, it can be seen that the cooling channels 6 can also extend radially between the stator slots 5 of the base body 4, i.e., into the stator tooth 16. The cooling channels 6 are thus each elongated in the radial direction.
[0054] The now U-shaped collecting channel 12 extends with its two circumferentially spaced-apart partial regions 18a, 18b, each forming a leg of the U, into the support web 17 / the stator tooth 16. It is advantageous if the respective radially extending partial region 18a, 18b of the collecting channel 12 has a smaller distance a1 from a circumferential edge / side flank of the stator tooth 16 / support web 17 to an inner side of the U (on the side of a stator slot 5 enclosed by the U) than to an outer side (distance b). A radial distance a2 between a bottom of the stator slot 5 and the circumferentially extending region of the U can in turn be greater than or equal to a1 and less than b.
[0055] In other words, Figures 1 to 4 show the first embodiment of the inventive solution. Intermediate sheets (first and third metal sheets 8a, 8c) are applied, which have a recess (collecting channel 12) to form channels or intermediate chambers. A cover sheet (second metal sheet 8b) is applied to the last intermediate sheet and has an opening (outlet opening 10), which serves as an outlet for winding head cooling. Here, two intermediate sheets were stacked on top of each other, although it is conceivable to apply only one or more to the laminated core 3. Sheets of different thicknesses can also be baked together. In the case of multiple intermediate sheets, the cooling channel created by the recess in the intermediate sheet 6 must be designed accordingly larger or smaller. The metal sheets 8 were conceived here as electrical sheets, so they are delivered pre-coated for easy baking.Ideally, they are baked onto the laminated core 3 during the bonding process. If the bonding process is to take place in a single step, then a step tool is required to apply full-surface pressure to the laminated core 3 before the bonding process. It is also conceivable to manufacture the sheets from structural steel, which is coated so that it can be baked onto the laminated core 3. Another option in this case is to glue the sheets. With this design, the sheets can be centered on the outer and / or inner diameter, with the laminated core preferably being centered on the inner diameter. If the sheets are to be centered on the inner diameter, they should preferably be centered using the step tool. Depending on the assembly sequence, segmentation can be advantageous in order to be able to assemble the sheets.
[0056] To explain the concept, Figures 3 and 4 show the intermediate plate with the recess, which serves as a channel and which fluidically connects the two channels of the laminated core 3, and the laminated core end plate, which has the various outlets from the cooling channels 6 in the laminated core 3. It is worth emphasizing here that the laminations preferably do not have an electromagnetic function. Although they can be made of a magnetic material suitable for stator laminations, they preferably do not have a tooth and therefore do not count towards the active length of the electric machine. Alternatively, however, the laminations can also be part of the active length of the electric machine. Particularly in the design of Figures 3 and 4,
[0057] In 13 and 14, the lamination tooth of the laminations (stator tooth 16 with support webs 17) corresponds exactly to the tooth of the laminated core, so the solution is part of the active length. Sealing of the intermediate channels is ensured by the bonding varnish and / or adhesive process.
[0058] A second design is shown in Fig. 5. This corresponds to the first design, except that it has smaller teeth than the teeth of the laminated core 3. This allows full-surface prestressing to be applied before the self-bonding process without a stepped tool, but since the teeth are smaller, they are preferably not counted towards the active length of the electric motor. Alternatively, as already mentioned, they can also be counted towards the active length. A further advantage of the smaller teeth is that the clearance and creepage distances are not affected. Depending on the requirements of the self-bonding process, a stepped tool, which leads to larger tolerances and thus lower self-bonding strength, can be dispensed with. In principle, the same alternatives exist as before (electric sheets possibly of different thicknesses, structural steel; self-bonding in one or two steps, segmentation, self-bonding, or bonding).
[0059] Fig. 6 shows the third embodiment, whereby the inventive solution here consists of only a single embossed cover sheet (metal sheet 8) instead of stacking several sheets on top of each other. The embossing on the cover sheet was designed so that both openings from the laminated core 3 are fluidly connected by an embossed chamber. Here, the sheet again has an opening for the winding head cooling outlet. Here, as with the first embodiments, the sheet can also be designed optionally: baked enamel process in 1 or 2 steps, centering on the inner or outer diameter, centering by the (stepped) tool from the baked enamel process, bonding, with and without small inner teeth for full-surface force application without a stepped tool, different thickness compared to the previous laminated core.
[0060] Figures 7 and 8 show another design. This is largely similar to the third design, except that it has an additional embossing on the opening so that the oil is redirected as desired to optimally cool the winding head.
[0061] From the previous designs, another design can be derived, which is shown in Figures 9 and 10. This corresponds to the first and second designs, in which one or more intermediate plates were attached, whereby the cover plate here has an additional embossing so that the oil is redirected as desired to optimally cool the winding head.
[0062] Furthermore, according to Figures 11 and 12, a variant made of plastic is shown. This was designed in segments here, whereby, depending on the assembly sequence and type of fastening, it is possible to provide an annular geometry (similar to the other designs). The oil line is pressed into the existing laminated core. For this purpose, the laminated core has bores and the oil guide ring 8 has integrated press-in pins (pins 19) distributed around the circumference. The sealing of the intermediate channels can be ensured by different solutions depending on the sealing requirement. If further improved sealing is required, a seal made of an elastomer can be provided. If low leakage is permitted, a seal can be omitted. A small gap between the oil line and the laminated core 3 is preferably sufficient to sufficiently reduce the resulting leakage.A bond that may be leaky depending on the requirements could also be acceptable.
[0063] List of reference symbols for electrical machine stator laminated core base body stator groove cooling channel end face metal sheet a first metal sheet b second metal sheet c third metal sheet diverter device 0 outlet opening 1 channel opening 2 collecting channel 3 through hole 4 diverter pocket 5 raised area 6 stator tooth 7 supporting web 8a first partial area 8b second partial area 9 journal 0 longitudinal axis 1 flank 2 plastic plate
Claims
Patent claims 1. An electric machine (1) for a motor vehicle, comprising a stator (2) of entirely annular design, the stator (2) further comprising a base body (4) consisting of a laminated core (3), the base body (4) being provided with axially extending stator slots (5) opening radially inwards, as well as axial cooling channels (6) positioned radially outside the stator slots (5) and / or in the circumferential direction between the stator slots (5), characterized in that a diverting device (9) comprising at least one metal sheet (8) or a plastic plate (22) and designed to divert a hydraulic medium flowing through the cooling channels (6) during operation is attached to an end face (7) of the base body (4), at least two cooling channels (6) being connected to a common outlet opening (10) of the diverting device (9).
2. Machine (1) according to claim 1, characterized in that the diverting device (9) has a plurality of metal sheets (8a, 8b, 8c) which are arranged axially overlapping one another and are fastened to one another.
3. Machine (1) according to claim 1 or 2, characterized in that a first metal sheet (8a) of the diverting device (9) forms a collecting channel (12) overlapping two axial channel openings (11) of two cooling channels (6).
4. Machine (1) according to claim 3, characterized in that the collecting channel (12) is designed as an axial through-hole (13) or a diverting pocket (14) formed by forming.
5. Machine (1) according to claim 3 or 4, characterized in that the collecting channel (12) is kidney-shaped, U-shaped or V-shaped.
6. Machine (1) according to one of claims 3 to 5, characterized in that the collecting channel (12) is connected to the outlet opening (10) formed directly in the first metal sheet (8a) or in a second metal sheet (8b) connected to the first metal sheet (8a).
7. Machine (1) according to one of claims 1 to 6, characterized in that the outlet opening (10) is aligned exclusively axially or is introduced into an axially exposed raised area (15) of a metal sheet (8) in such a way that it is at least partially inclined inwards in a radial direction.
8. Machine (1) according to one of claims 1 to 7, characterized in that the at least one metal sheet (8) has a constant radial inner diameter.
9. Machine (1) according to one of claims 1 to 8, characterized in that the at least one metal sheet (8) has a radially inwardly projecting support web (17) for each stator tooth (16) of the base body (4), which support web (17) bears against the stator tooth (16) of the base body (4).
10. Machine (1) according to claim 9, characterized in that the at least one metal sheet (8) is provided with a collecting channel (12) and the collecting channel (12) has two radially extending partial areas (18a, 18b) which are spaced apart from one another in the circumferential direction and are inserted into different support webs (17), wherein the support webs provided with the partial areas (18a, 18b) are of different widths towards the sides of the partial areas (18a, 18b).