Electric machine with oil cooling

Abstract

The present invention relates to an electrical machine (1) comprising a rotor with a rotor shaft (3) which is at least partially hollow and which is mounted on a machine housing (4) and extends along an axial direction (100), a coolant connection line module (5) with a fluid inlet nozzle (6) and a fluid outlet nozzle (7), wherein the fluid inlet nozzle (6) is fluidically connected to a coolant channel (8) of the machine housing (4), wherein the fluid outlet nozzle (7) projects in the axial direction (100) into the hollow rotor shaft (3), characterized in that the coolant connection line module (5) has at least one outlet fastening section (10) which is different from the fluid inlet nozzle (6) and the fluid outlet nozzle (7), which is arranged closer to the fluid outlet nozzle (7) than to the fluid inlet nozzle (6), and is fastened via the outlet fastening section (10) at least in the axial direction (100) to the Machine housing (4) is attached.

Description

State of the art

[0001] The present invention relates to an electric machine. The electric machine comprises a rotor with a hollow shaft and a coolant connection line module for introducing coolant into the shaft.

[0002] Various types of coolant connection modules are known from the prior art, which are intended for spraying cooling fluids such as oil. Such modules are described, for example, in documents CA 2 788 386 A1, US 2015 027388 A1, KR 1998 0029811 A, US 2018 126405 A1, and KR 2005 0058676 A. Disclosure of the invention

[0003] The electric machine has a rotor, wherein the rotor comprises a rotor shaft that is at least partially hollow. The rotor shaft is mounted on a machine housing and extends along an axial direction. Furthermore, a coolant connection line module with a fluid inlet nozzle and a fluid outlet nozzle is provided. The fluid outlet nozzle protrudes into the hollow rotor shaft in the axial direction. The fluid inlet nozzle is fluidly connected to a coolant channel of the machine housing.

[0004] The coolant connection line module has an outlet attachment section that is different from the fluid inlet port and the fluid outlet port. This outlet attachment section is arranged closer to the fluid outlet port than to the fluid inlet port. The coolant connection line module is attached to the machine housing at least in the axial direction via the outlet attachment section.

[0005] The outlet fastening section enables reliable fixation of the entire coolant connecting line module, but in particular of the fluid outlet nozzle within the rotor shaft. The fluid outlet nozzle therefore only needs to protrude a shorter distance into the hollow rotor shaft. The material of the coolant connecting line module can therefore be designed to be more cost-effective and thus less rigid, since the outlet fastening section provides additional stability. The entire coolant connecting line module can thus be manufactured more easily and cost-effectively than previously possible with the prior art. Furthermore, the fluid outlet nozzle, in particular, can be precisely aligned within the hollow rotor shaft.

[0006] The subclaims show preferred developments of the invention.

[0007] The coolant connecting line module preferably has an inlet fastening section that is different from the fluid inlet nozzle and the fluid outlet nozzle. The inlet fastening section is arranged closer to the fluid inlet nozzle than to the fluid outlet nozzle. The fluid inlet nozzle, in particular, has a support foot with a screw passage. It is provided that the fluid outlet nozzle, preferably via said support foot with screw passage, is designed to fasten the coolant connecting line module to the machine housing. Thus, in particular, the coolant connecting line module is fastened at two points on the machine housing. On the one hand, a connection advantageously takes place at the outlet fastening section, and on the other hand, preferably at the inlet fastening section.The coolant connection line module is therefore optimally attached to the machine housing, as well as optimally aligned with the machine housing. This allows, in particular, the use of less stable and cost-effective materials. By dividing the connection of the coolant connection line module to the machine housing into an inlet mounting section and an outlet mounting section, the coolant connection line module can be optimally fixed near the relevant fluid transfer points.

[0008] It is particularly advantageous that retaining elements are formed on the inlet fastening section. The retaining elements serve to connect cables of a wiring harness of the electric machine. The coolant connecting line module thus fulfills an additional task, namely holding cables to the machine housing. Additional fastening components on the machine housing for holding and / or guiding cables are therefore avoided. This reduces the number of required parts compared to the prior art. Such retaining elements are formed, in particular, integrally with the inlet fastening section.

[0009] The outlet fastening section advantageously has at least one locking element. The locking element serves to create a locking connection, whereby an axial fixation of the coolant connecting line module is achieved. The axial fixation means that, in particular, removal of the coolant connecting line module in the axial direction away from the rotor shaft is prevented. Thus, in particular, the fluid outlet nozzle is optimally arranged within the hollow rotor shaft. The locking connection is easy to create; in particular, the locking connection occurs automatically by inserting the fluid outlet nozzle into the rotor shaft. Particularly advantageously, the locking element is designed as a flexible snap hook or similar, which engages behind an edge to create the locking connection. The outlet fastening section preferably has at least two fastening elements, such as locking elements.The locking elements are arranged, in particular, around the fluid outlet nozzle. This means, in particular, that the locking elements are located on an arc around the fluid outlet nozzle. The locking elements extend, in particular, in a U-shape as a spring arm in the axial direction. It is preferably provided that the locking elements engage behind the machine housing or a component attached to the machine housing. In this way, a reliable locking connection is established, with the fluid outlet nozzle being optimally fixed. The fluid outlet nozzle can thus protrude into the hollow rotor shaft as the free end of the coolant connection line module. Both the alignment and the fixing of the fluid outlet nozzle are ensured by the locking elements.

[0010] The fluid inlet nozzle is preferably inserted into the coolant channel of the machine housing. Furthermore, it is provided that the fluid inlet nozzle rests against a wall of the coolant channel, in particular by means of a seal. The contact with the wall of the coolant channel preferably fulfills a sealing effect, which is why the seal is advantageously provided. In a particularly advantageous embodiment, the fluid inlet nozzle is not fixed within the coolant channel, apart from the frictional connection necessary for the sealing effect. A positive connection and / or screw connection preferably does not take place. Rather, the fluid inlet nozzle is fixed within the coolant channel by the coolant connecting line module being attached to the machine housing.The described inlet mounting section is particularly advantageous for this purpose, connecting the coolant connecting line module to the machine housing near the fluid inlet nozzle. Direct attachment of the fluid inlet nozzle to the coolant channel, e.g., via a central screw with a hollow screw body, is not necessary.

[0011] In an advantageous embodiment, the coolant connecting line module is formed in one piece. In particular, the coolant connecting line module is manufactured by injection molding with gas injection. This makes the manufacturing process simple and cost-effective, while also allowing the use of a cost-effective material. Injection molding with gas injection allows any desired shape of the coolant connecting line module to be realized easily and cost-effectively. The coolant connecting line module can thus be adapted easily and with little effort to specific conditions at the site of use, in particular to configurations of the electrical machine. In particular, a coolant channel is created by gas injection. The coolant channel extends between the fluid inlet and the fluid outlet.The one-piece design of the coolant connection line module ensures that the channel for the coolant is sealed, thus minimizing the risk of unintentional coolant leakage.

[0012] In an alternative embodiment, the coolant connecting line module is preferably designed in several parts. In this case, the coolant connecting line module has a lower part and an upper part. The fluid inlet nozzle and / or fluid outlet nozzle and / or inlet fastening section and / or outlet fastening section are formed on the lower part. The upper part is fastened to the lower part and serves in particular as a cover. A fluid line channel is formed between the upper part and the lower part in order to transport fluid from the fluid inlet nozzle to the fluid outlet nozzle. The multi-part design simplifies production. In particular, gas injection or the like can be dispensed with. The individual parts, i.e. the upper part and the lower part, are preferably designed without undercuts and can therefore be optimally manufactured using injection molding or other casting processes.

[0013] Particularly preferably, the upper part and the lower part each have a groove-shaped cavity. The groove-shaped cavity serves to conduct the coolant. If the upper part and lower part are fastened to one another, the respective groove-shaped cavities together preferably form a cooling channel for conducting the coolant. Furthermore, it is particularly advantageous that the upper part and lower part each have a shoulder adjacent to the groove-shaped cavity on both sides. The shoulder serves to join the upper part and lower part. Said joining is preferably carried out by means of a material bond, in particular by welding. Such joining ensures in particular that the channel formed by the groove-shaped cavities is tight, thereby minimizing the risk of unwanted leakage of the coolant.

[0014] Advantageously, the lower part and the upper part are centered relative to one another. This is preferably achieved by at least one bore in the lower part into which a pin from the upper part is inserted. Alternatively or additionally, the upper part has a bore into which a pin from the lower part is inserted. This allows the upper and lower parts to be easily and reliably centered relative to one another. This reliably enables the formation of the cooling channel through the upper and lower parts. Centering also allows the upper and lower parts to be optimally joined, making fastening the two parts simple and inexpensive.

[0015] The upper and lower parts are advantageously each formed as a single piece. In particular, the upper and lower parts are manufactured by injection molding.

[0016] In an advantageous embodiment, the coolant connecting line module is made of plastic. In particular, the coolant connecting line module does not have to withstand high fluid pressures, which is why the plastic design is simple and inexpensive. The use of plastic also preferably leads to reduced material costs for the coolant connecting line module.

[0017] The electric machine preferably has a resolver stator for determining an alignment of the rotor shaft. The resolver stator surrounds the rotor shaft in a ring shape, in particular at one end of the rotor shaft, particularly advantageously on the B-side of the electric machine. The resolver stator is also fastened to the machine housing, which is achieved in particular by screwing. It is provided that the outlet fastening section of the coolant connecting line module is fastened to the resolver stator. Particularly advantageously, the outlet fastening section is fastened to the resolver stator by means of a snap-in connection. This fastening can particularly advantageously take place before the resolver stator is installed, so that the resolver stator and coolant connecting line module can be installed together. This leads to simplified installation of the electric machine.In particular, individual elements of the electrical machine can be pre-assembled, making the entire assembly process simpler, more flexible and faster.

[0018] The coolant connecting line module preferably has an additional outlet for discharging cooling fluid in addition to the fluid outlet nozzle. The additional outlet is particularly advantageously located closer to the fluid outlet nozzle than to the fluid inlet nozzle. The additional outlet can supply additional areas with cooling fluid, for example, fill a reservoir via a free jet.

[0019] The coolant is particularly advantageously an oil. The oil is fed through the hollow rotor shaft and is used in particular to cool the rotor and / or a stator winding. Short description of the drawings

[0020] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. In the drawing: Fig. 1 a schematic view of an electrical machine according to an embodiment of the invention, Fig. 2 a schematic detailed view of the electric machine according to the embodiment of the invention, in particular a coolant connection line module of the electric machine, Fig. 3 a schematic sectional view through a partial area of ​​the electrical machine, in particular through the coolant connection line module, Fig. 4 a schematic representation of the coolant connection line module of the electric machine according to the embodiment of the invention, Fig. 5a a schematic representation of a cable harness of the electric machine according to the embodiment of the invention, Fig. 5b a schematic representation of the pre-assembly of the cable harness and coolant connection line module of the electric machine according to the embodiment of the invention, and Fig. 6 a schematic detailed representation of the electrical machine according to the embodiment of the invention. Embodiments of the invention

[0021] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0022] Fig. 1 schematically shows an electric machine 1 according to an embodiment of the invention. The electric machine 1 has a rotor 2, which is driven by a stator 19. The rotor 2 has a rotor shaft 3 that is at least partially hollow. The rotor shaft 3 extends along an axial direction 100 and is mounted on a machine housing 4. In Fig. 1 shows that the rotor shaft 3 is mounted on a bearing plate 4a. The stator 19 is also attached to the machine housing 4, for example, to a pot-shaped housing part 4b. The bearing plate 4a and other housing parts 4b are hereinafter referred to collectively as the machine housing 4.

[0023] The machine housing 4, in particular the bearing plate 4a, has a coolant channel 8. The coolant can be guided from the coolant channel 8 of the machine housing 4 into the interior of the hollow rotor shaft 3 via a coolant connection line module 5. For this purpose, the coolant connection line module 5 has a fluid inlet nozzle 6 and a fluid outlet nozzle 7, wherein a coolant channel extending at least partially along a radial direction 200 is provided in the coolant connection line module 5 between the fluid inlet nozzle 6 and the fluid outlet nozzle 7.

[0024] The fluid inlet nozzle 6 is inserted into the coolant channel 8 of the machine housing. The fluid outlet nozzle 7 projects in the axial direction 100 into the hollow rotor shaft 3. In particular, the coolant connecting line module 5 is not fixed and aligned via the fluid inlet nozzle 6 and / or fluid outlet nozzle 7, but rather by at least one inlet fastening section 9 and outlet fastening section 10 that are different from the fluid inlet nozzle 6 and the fluid outlet nozzle 7. The inlet fastening section 9 is arranged closer to the fluid inlet nozzle 6 than to the fluid outlet nozzle 7. The outlet fastening section 10 is arranged closer to the fluid outlet nozzle 7 than to the fluid inlet nozzle 6.

[0025] Fig. 2 schematically shows a partial view of the electric machine 1, wherein in particular the coolant connection line module 5 is shown. Fig. Figure 3 schematically shows a sectional view through a portion of the electric machine 1, wherein in particular the coolant connecting line module 5 is shown in section. The section is made along the section line A: A as in Fig. 2 shown.

[0026] In the illustrated embodiment, the coolant connecting line module 5 is constructed in multiple parts. It includes a lower part 5a and an upper part 5b secured to the lower part 5a. The fluid inlet connector 6, the fluid outlet connector 7, the inlet fastening section 9, and the outlet fastening section 10 are formed on the lower part 5a. The lower part 5a is constructed in one piece. In particular, the lower part 5a can be manufactured by injection molding and preferably has no undercuts. Likewise, the upper part 5b can preferably be manufactured by injection molding and also has no undercuts.

[0027] The lower part 5a and the upper part 5b preferably each have a groove-shaped cavity 5c, which serves to conduct the coolant. Furthermore, shoulders 12a, 12b are provided on both sides adjacent to the groove-shaped cavity 5c. These shoulders 12a, 12b serve to join the upper part 5b and the lower part 5a. The joining is particularly effected by a material bond, particularly advantageously by welding. This ensures that the coolant cannot escape from the groove-shaped cavity 5c.

[0028] The inlet fastening section 9 preferably has a support foot with a screw passage 9a. The inlet fastening section 9 and thus the coolant connecting line module 5 can be fastened to the machine housing 4 via this support foot with a screw passage 9a. In particular, the fluid inlet nozzle 6 is not directly fastened. Rather, it is merely provided that the fluid inlet nozzle 6 rests against an opening 8a of the coolant channel 8 in order to create a seal. A seal 11 is also particularly advantageously provided to improve the seal between the fluid inlet nozzle 6 and the coolant channel 8. A screw connection and / or positive connection between the fluid inlet nozzle 6 and the coolant channel 8 is in particular not provided.

[0029] The coolant connection line module 5 is also fixed to the machine housing 4 by the outlet fastening section 10. For this purpose, the outlet fastening section 10 has at least one locking element 10a for establishing a locking connection which enables a positive connection at least in the axial direction 100.

[0030] Said locking connection of the outlet fastening section 10 is achieved by a plurality of locking elements 10a, wherein the locking elements 10a are arranged in an arc around the fluid outlet nozzle 7. Each locking element 10a extends as a U-shaped spring arm in the axial direction 100 and engages behind a resolver stator 17. The resolver stator 17 is provided for determining an alignment of the rotor shaft 3 and surrounds the rotor shaft 3 in a ring-like manner. The resolver stator 17 is fastened to the machine housing 4 via a plurality of screws. By fastening the resolver stator 17 to the machine housing 4, the coolant connecting line module 5 is also fastened to the machine housing 4. The locking elements 10a of the outlet fastening section 10 allow the outlet fastening section 10 and thus the coolant connecting line module 5 to be easily and reliably fastened to the resolver stator 17.This allows, in particular, pre-assembly of the coolant connecting line module 5 on the resolver stator 17. This enables joint assembly of the coolant connecting line module 5 and the resolver stator 17. By mounting the outlet fastening section 10 on the resolver stator 17, the fluid outlet nozzle 7 also engages in the hollow rotor shaft 3. The alignment of the fluid outlet nozzle 7 to the rotor shaft 3 occurs simultaneously with the alignment of the resolver stator 17 to the rotor shaft 3. In particular, centering is thus possible in a simple and low-effort manner.

[0031] The inlet fastening section 9 is designed as a support base with a screw passage 9a for fastening the inlet fastening section 9 to the machine housing 4 by means of a screw. In addition, the inlet fastening section 9 has holding elements 15 for connecting cables 16a of a cable harness 16 of the electric machine 1. The cables 16a can thus be fastened and / or routed to the coolant connection line module 5. To achieve centering of the upper part 5b and the lower part 5a, the upper part 5b in the illustrated embodiment has two bores 13. A pin 14 of the lower part 5a engages in each bore 13. This aligns the upper part 5b and the lower part 5a relative to each other.

[0032] The upper part 5b also has an additional outlet 18. The additional outlet 18 serves to discharge the cooling fluid in addition to the fluid outlet nozzle 7.

[0033] This allows an additional location to be supplied with cooling fluid. For example, a reservoir can be filled via the additional outlet 18 using a free jet.

[0034] Fig. 4 shows schematically the coolant connection line module 5. Fig. 5a schematically shows a cable harness 16 of the electric machine 1. The cable harness 16 has several cables 16a, which in particular contact the resolver stator 17 and a temperature sensor 20. To simplify the manufacture and assembly of the electric machine 1, the cable harness 16 and the coolant connection line module 5 are pre-assembled. This is shown in Fig. 5b. On the one hand, the outlet fastening section 10 is fastened to the resolver stator 17 by means of the locking elements 10a. In addition, cables 16a of the cable harness 16 are guided on the coolant connecting line module 5 and held in particular by means of the holding elements 15 of the inlet fastening section 9. In a further step, the cable harness 16 can thus be mounted together with the coolant connecting line module 5 on the electric machine 1. This state is shown in Fig. 6. In particular, the temperature sensor 20 is mounted on the stator 19 or near the stator 19 to detect its temperature. The resolver stator 17 is attached to the machine housing 4, whereby the coolant connection line module 5 is also attached to the machine housing 4, with the fluid outlet nozzle 7 projecting into the hollow rotor shaft 3 in the axial direction 100.

[0035] In the exemplary embodiment shown, the coolant connecting line module 5 is preferably made of plastic, in particular in multiple parts by injection molding individual parts. Alternatively, the coolant connecting line module 5 can also be manufactured in one piece, in particular by injection molding with gas injection. In all cases, the coolant connecting line module 5 can be manufactured easily and with little effort. The manufacturing costs for the coolant connecting line module 5 are minimized. In addition, the coolant connecting line module 5 can perform additional tasks, such as fastening and guiding cables 16a of the cable harness 16. Assembly takes place in particular together with the resolver stator 17. Thus, on the one hand, additional components, such as additional cable guides for the cables 16a, are not necessary, and on the other hand, the assembly of the electrical machine is simplified. 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] CA 2 788 386 A1

[0002] US 2015 027388 A1

[0002] KR 1998 0029811 A

[0002] US 2018 126405 A1

[0002] KR 2005 0058676 A

[0002]

Claims

[1] Electrical machine (1) comprising - a rotor (2) with an at least partially hollow rotor shaft (3) which is mounted on a machine housing (4) and extends along an axial direction (100), - a coolant connection line module (5) with a fluid inlet nozzle (6) and a fluid outlet nozzle (7), - wherein the fluid inlet nozzle (6) is fluidly connected to a coolant channel (8) of the machine housing (4), - wherein the fluid outlet nozzle (7) projects in the axial direction (100) into the hollow rotor shaft (3), characterized byin that the coolant connection line module (5) has at least one outlet fastening section (10) which is different from the fluid inlet nozzle (6) and the fluid outlet nozzle (7), which is arranged closer to the fluid outlet nozzle (7) than to the fluid inlet nozzle (6), and is fastened to the machine housing (4) via the outlet fastening section (10) at least in the axial direction (100). [2] Electrical machine (1) according to claim 1, characterized by in that the coolant connection line module (5) has an inlet fastening section (9) which is different from the fluid inlet nozzle (6) and the fluid outlet nozzle (7), which inlet fastening section is arranged closer to the fluid inlet nozzle (6) than to the fluid outlet nozzle (7), and which in particular has a support foot with a screw passage (9a) for fastening to the machine housing (4). [3] Electrical machine (1) according to claim 2, characterized bythat holding elements (15) for connecting cables (16a) of a cable harness (16) of the electrical machine (1) are formed on the inlet fastening section (9). [4] Electrical machine (1) according to one of the preceding claims, characterized by that the outlet fastening section (10) has at least one locking element (10a) for establishing a locking connection for fixing the coolant connection line module (5) at least in the axial direction (100), [5] Electrical machine (1) according to claim 4, characterized by that the outlet fastening section (10) has at least two locking elements (10a) which - are arranged around the fluid outlet nozzle (7), - each extend as a spring arm, in particular a U-shaped one, in the axial direction (100), and - engage behind the machine housing (4) or a component attached to the machine housing (4). [6] Electrical machine (1) according to one of the preceding claims, characterized by that the fluid inlet nozzle (6) is inserted into the coolant channel (8) of the machine housing (4) and, in particular by means of a seal (11), rests against a wall (8a) of the coolant channel (8). [7] Electrical machine (1) according to one of the preceding claims, characterized by that the coolant connecting line module (5) is formed in one piece and is produced in particular by injection molding with gas injection. [8] Electrical machine (1) according to one of claims 1 to 6, characterized by that the coolant connection line module (5) is designed in several parts and has a lower part (5a), on which the fluid inlet nozzle (6) and / or the fluid outlet nozzle (7) and / or the inlet fastening section (9) and / or the outlet fastening section (10) are formed, and an upper part (5b) fastened to the lower part (5a). [9] Electrical machine (1) according to claim 8, characterized by that the upper part (5b) and the lower part (5a) each have a groove-shaped cavity (5c) for conducting the coolant and a shoulder (12a, 12b) adjacent to the groove-shaped cavity (5c) on both sides for joining, in particular welding, the upper part (5b) and the lower part (5a). [10] Electrical machine (1) according to claim 8 or 9, characterized by that the lower part (5a) and the upper part (5b) are centered relative to one another, in particular by at least one bore (13) of the lower part (5a) into which a pin (14) of the upper part (5b) is inserted and / or by at least one bore (13) of the upper part (5b) into which a pin (14) of the lower part (5a) is inserted. [11] Electrical machine (1) according to one of claims 8 to 10, characterized bythat the lower part (5a) and the upper part (5b) are each formed in one piece, wherein the lower part (5a) and the upper part (5b) are produced in particular by injection moulding. [12] Electrical machine (1) according to one of the preceding claims, characterized by that the coolant connection line module (5) is made of plastic. [13] Electrical machine (1) according to one of the preceding claims, characterized by that the electrical machine (1) has a resolver stator (17) for determining an alignment of the rotor shaft (3), - wherein the resolver stator (17) surrounds the rotor shaft (3) in a ring shape, - wherein the resolver stator (17) is fastened to the machine housing (4), in particular by screwing, and - wherein the outlet attachment portion (10) of the coolant connection line module (5) is attached to the resolver stator (17). [14] Electrical machine (1) according to one of the preceding claims, characterized by that the coolant connection line module (5) has an additional outlet (18) for discharging cooling fluid in addition to the fluid outlet nozzle (7).

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