Stator for an electric machine for a powertrain for a vehicle, electric machine, and powertrain

Abstract

The invention relates to a stator (1) for an electric machine for a powertrain for a vehicle, comprising a laminated stator core (2); a stator winding (3), the stator winding (3) comprising a first winding head (4) and a second winding head (5); and a second winding head housing (7) for the second winding head (5). The stator is characterized in that the second winding head housing (7) comprises a disc element (8) for distributing a cooling liquid within the second winding head housing (7), the second winding head housing (7) comprises a cylindrical hollow-body element (9) for covering the second winding head (5) inwards in the radial direction, and the disc element (8) and the hollow-body element (9) are provided as separate components which are connected to one another via a connection (10). The invention further relates to an electric machine and to a powertrain.

Description

[0001] Stator for an electric machine for a vehicle powertrain,

[0002] Electric machine, drive train

[0003] The invention relates to a stator for an electric machine for a drive train for a vehicle, comprising a stator lamination stack, a stator winding, wherein the stator winding comprises a first winding head and a second winding head, a second winding head housing for the second winding head, an electric machine with such a stator, and a drive train with such a stator.

[0004] Stators for electric machines are generally known from the prior art. These electric machines can be, among other things, electric motors used in the drive trains of vehicles such as electric or hybrid vehicles. For efficiency reasons, the stator is cooled, with the winding heads typically being enclosed to allow coolant flow from a first winding head, across the stator lamination stack, to a second winding head. During stator manufacturing, particular problems arise in the so-called twisting process for the winding head, as the winding head housing represents an interfering contour.

[0005] An electrical machine is known from DE 102017205418 B3.

[0006] A motor oil cooling system is known from CN 116054441 A.

[0007] A motor oil cooling system is known from CN 116111753 A.

[0008] The KR 100828799 B1 document describes an oil cooling system for an engine.

[0009] In this context, it has become apparent that there is a need to provide a stator for an electric machine for a vehicle powertrain, and in particular, a need to provide an improved stator for an electric machine for a vehicle powertrain. It is therefore an object of the present invention to eliminate, or at least partially eliminate, the disadvantages described above in a stator for an electric machine for a vehicle powertrain. In particular, it is an object of the present invention to provide an improved stator for an electric machine for a vehicle powertrain.

[0010] This problem is solved in a stator of the generic type according to the invention in that the second winding head housing comprises a disk element for distributing a cooling fluid within the second winding head housing, and wherein the second winding head housing comprises a cylindrical hollow body element for covering the second winding head in a radial direction inwards, wherein the disk element and the hollow body element are designed as separate components that are connected to each other via a connection. In particular, the problem is solved by a stator with the features of independent claim 1.

[0011] Furthermore, the problem is solved by an electric machine having the features of independent claim 9 and by a drive train having the features of independent claim 10.

[0012] Features disclosed in connection with the stator according to the invention naturally also apply in connection with the electrical machine and the drive train according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes or can make reciprocal reference.

[0013] A first aspect of the present invention relates to a stator for an electric machine for a drive train for a vehicle, comprising a stator lamination stack, a stator winding, wherein the stator winding comprises a first winding head and a second winding head, a second winding head housing for the second winding head,

[0014] characterized in that the second winding head housing comprises a disk element for distributing a cooling liquid within the second winding head housing, and wherein the second winding head housing comprises a cylindrical hollow body element for covering the second winding head in a radial direction inwards, wherein the disk element and the hollow body element are designed as separate components that are connected to each other via a connection.

[0015] The term "electric machine" refers to a machine that can convert electrical energy into mechanical energy and vice versa. An electric machine can include an electric motor. An electric machine can include a generator. An electric machine can include an AC-based electric motor. An electric machine can include an asynchronous motor. An electric machine can include a synchronous motor.

[0016] In this context, the term stator lamination stack refers in particular to a large number of lamination sections arranged in a row to optimize the magnetic properties of the stator.

[0017] In this context, the term "sheet metal section" refers specifically to a thin sheet metal element. The sheet metal section can be made of a metal, steel, particularly silicon steel.

[0018] The term stator winding refers in particular to a winding arranged in a slot in the stator, which generates a magnetic field when current flows. The stator winding can preferably be sealed radially inwards from the stator's interior. The term slot refers in particular to a recess extending longitudinally along the stator for receiving the stator winding. The stator can preferably have a plurality of slots, which can preferably be evenly distributed around its circumference. The stator winding can preferably be a hairpin winding.

[0019] The term "winding head" refers to a section of the stator winding located outside the laminated core or magnetic core, connecting the active winding wires of the stator winding in the stator slots to form a closed electrical circuit. The first winding head preferably refers to a winding head of a hairpin winding located on the insertion side of the hairpin winding. The second winding head preferably refers to a winding head located on the weld side of the hairpin winding.

[0020] The term "winding head housing" refers to an enclosure designed to protect the winding head from its surroundings. The winding head housing is preferably composed of multiple parts. It may have an interface for an inlet or outlet for a coolant, such as oil. The coolant can flow into the first winding head housing through an interface and cool the winding head there. From the first winding head housing, the coolant can flow through a cooling channel, which may be located in the stator lamination stack, into the second winding head housing to cool the second winding head. From there, the coolant can exit through an interface in the winding head housing. The coolant can be pumped. Preferably, a cooling circuit is present.The winding head housing may preferably include, in addition to the disc element and the cylindrical hollow body, further housing elements for enclosing the winding head. These embodiments apply to a first winding head housing and / or a second winding head housing.

[0021] The term disc element refers in particular to an annular plate designed to channel coolant between a cooling channel located inside a stator and an interior space of the winding head housing. For this purpose, the disc element may have a distribution channel or a collection channel. The distribution channel may extend radially from the outside to the inside. The disc element may have interfaces for connection to the cooling channel and / or the interior space. The disc element may be a single piece or multi-piece. The disc element may be an injection-molded part. The disc element may be made of plastic. The disc element can guide coolant from an interior space of the winding head housing into the cooling channel or vice versa. The disc element may preferably be connected to an end face of the stator lamination stack. This connection may be made, for example, via a screw connection or an adhesive bond.The following applies to a disc element of the first winding head housing and / or to a disc element of the second winding head housing.

[0022] The term "cylindrical hollow body element" refers to a structural element designed to cover the winding head radially inwards from the stator's interior, preventing coolant from flowing into the stator's interior. The cylindrical hollow body element can be a single piece or multiple pieces. It can be made of plastic or be an injection-molded component. These descriptions apply to a cylindrical hollow body element of the first winding head housing and / or to a cylindrical hollow body element of the second winding head housing.

[0023] The invention is based on the understanding that winding heads are twisted to increase their mechanical stability. For this purpose, a tool must engage the winding head and twist it. To engage, the tool requires space in the radial direction inwards and in the axial direction to the end of the winding head housing. Previously, the cylindrical hollow body and the disc element were manufactured as a single injection-molded component. This resulted in an obstruction for the tool used to twist the winding head. To overcome this problem, the invention proposes manufacturing the cylindrical hollow body and the disc element as separate components. The disc element can then be mounted, the stator winding inserted into the stator slots, and welded in place. The tool for the twisting process can then enter the first or second winding head without an obstruction and twist it.The cylindrical hollow body can then be mounted, for example by bonding it to the disc element. This advantageously enables or improves access for the tool used to twist the winding head, resulting in an optimized stator and thus improved stator performance.

[0024] Advantageous embodiments are claimed in the dependent claims and are explained in more detail below. According to a preferred embodiment, the cylindrical hollow body element can comprise at least one rib element, wherein the cylindrical hollow body element can be arranged in the axial longitudinal direction on an outer surface of the hollow body element to extend a creepage distance for a creepage current between two phases of the stator winding.

[0025] The term rib element preferably refers to a structural wall-shaped element that is designed to extend a creepage distance.

[0026] On the welded side, the Haipin winding, the ends of the stator winding are no longer insulated due to the welding process. This can lead to a short circuit between two phases of the stator winding due to leakage currents flowing across the outer surface of the cylindrical hollow body. The addition of a ribbed element can advantageously lengthen the leakage current path, thus minimizing the risk of a short circuit. The ribbed element can be positioned, in particular, between two phases. The addition of a ribbed element is only possible in combination with the two-part, separate design of the disk element and the cylindrical hollow body, as otherwise the assembly and / or twisting process would be impossible or extremely difficult.

[0027] According to a preferred embodiment, the cylindrical hollow body element can comprise at least one wall element which can be arranged circumferentially on an outer surface of the hollow body element to extend a creepage distance for a creepage current between two phases of the stator winding.

[0028] The leakage current can creep not only circumferentially to an adjacent phase, but also longitudinally and then circumferentially. To prevent this, a wall element can advantageously be used. The wall element can preferably be arranged on an end face in front of the ends of the winding head. Preferably, the wall element can be connected to the rib element to at least partially surround one end of a phase. In this way, the risk of a short circuit can be advantageously reduced synergistically.According to a preferred embodiment, the disk element can comprise at least one first interface for coolant flow between the disk element and an interior of the second winding head housing, wherein the disk element can comprise at least one second interface for coolant flow between the disk element and the stator lamination stack, and wherein the disk element can have at least one distribution channel extending radially from the outside to the inside to connect the first interface and the second interface. The first interface and / or second interface can, for example, include a bore. The second interface can, for example, be fluidically connected to a cooling channel extending axially within the stator lamination stack. The distribution channel can allow the introduction of coolant into a lower region of the interior of the second winding head housing.This can have a beneficial effect on the cooling of the second winding head.

[0029] According to a preferred embodiment, the stator can comprise a first winding head housing for the first winding head, wherein the first winding head housing can include a disk element for collecting the coolant inside the first winding head housing, and wherein the first winding head housing can include a cylindrical hollow body element for covering the first winding head in a radial direction inwards, wherein the disk element and the hollow body element can be designed as separate components that are connected to each other via a connection.

[0030] The disk element preferably has at least one collecting channel that directs coolant from an interior space of the first winding head housing into a cooling channel located within a stator lamination stack. The connection between the disk element and the cylindrical hollow body can be achieved, for example, by bonding.

[0031] The two-part, separate design of the disc element and the cylindrical hollow body in the first winding head housing advantageously optimizes assembly, as the twisting process must also be performed here. According to a preferred embodiment, the hollow body element of the first winding head housing can have at least one wall section extending at least partially circumferentially on an end face to increase stiffness, and / or the hollow body element of the first winding head housing can have at least one axially extending rib element on its outer surface to increase stiffness.

[0032] In the first winding head housing, the plug-in side of the stator winding is preferably located. The problem of leakage currents does not occur there. However, an increased mechanical load can act on the cylindrical hollow body due to the coolant inlet. The stiffness can be advantageously increased synergistically by arranging a wall section and a rib element. The wall section can preferably be located on an end face facing away from the laminated core. The separate design of the cylindrical hollow body and the disk element makes the arrangement of the wall section and rib element possible, as they would otherwise present an interfering contour for the first winding head during assembly.

[0033] According to a preferred embodiment, the stator lamination stack can include at least one cooling channel, wherein the cooling fluid can flow between the first winding head through the at least one cooling channel and the second winding head.

[0034] The term cooling channel, in this context, refers to a channel for conveying a coolant. The cooling channel can be a single piece or multiple pieces. It can be created by means of cutouts in the sheet metal stack. For example, the cooling channel can be created by punching the sheet metal sections. The cooling channel can allow flow in both directions. A pump can be used to circulate the coolant through the cooling channel. Preferably, a cooling circuit is used.

[0035] According to a preferred embodiment, the connection of the second winding head housing and / or the connection of the first winding head housing may comprise one or more of the following: adhesive bonding, welding, screwing, and / or wherein the disk element of the second winding head housing and / or the disk element of the first winding head housing and / or the hollow body element of the second winding head housing and / or the hollow body element of the first winding head housing may comprise as a material of one or more of the following: PPA, PPS.

[0036] Another aspect of the present invention relates to an electric machine with a stator described in more detail above.

[0037] A further aspect of the present invention relates to a drive train with a stator and / or an electric machine described above.

[0038] In this context, the term drivetrain refers to an assembly designed to transmit drive energy to the wheels of a vehicle. The drivetrain can include one or more of the following: electric motor, control unit, transmission, gearbox, differential, clutch, brake, axle, wheel hub.

[0039] The invention is explained below with the aid of a drawing. The drawing shows:

[0040] Figure 1 shows a stator according to the invention,

[0041] Figure 2 shows a disc element and a hollow body element.

[0042] Figure 3 shows a detailed view of a first winding head housing,

[0043] Figure 4 shows a detailed view of a second winding head housing, and

[0044] Figure 5 shows a detailed view of a winding head housing.

[0045] Identical elements are provided with the same reference numerals. Features of the individual embodiments can be interchanged, complemented, or replaced. Figure 1 shows a stator 1 according to the invention for an electric machine for a vehicle drive train. The electric machine is an electric motor. The stator 1 comprises a laminated core 2. A cooling channel 21 runs axially within the laminated core 2. A stator winding 3 is arranged within a slot in the laminated core 2. The stator 2 has a plurality of slots distributed around its circumference. The stator 2 comprises a first winding head 4 and a second winding head 5. The stator winding 3 is a hairpin winding. The first winding head 4 corresponds to the plug-in side and the second winding head 5 to the welded side of the stator winding 3. The first winding head 4 is enclosed by a first winding head housing 6.The second winding head 5 is enclosed by a second winding head housing 7. A coolant flows into the first winding head housing 6 and cools the first winding head 4. From the first winding head 4, the coolant flows via the cooling channel 21 to the second winding head 5 to cool it as well. The coolant then flows out of the second winding head housing 7 via a closed loop. The second winding head housing 7 includes a disc element 8 for distributing the coolant within the second winding head housing 7. The disc element 8 includes a first interface 14 and a second interface 16 for directing coolant from the cooling channel 21 via the distribution channel (not shown) into an interior 15 of the second winding head housing 7. The second winding head housing 7 includes a cylindrical hollow body element 9 for covering the second winding head 5 radially inwards.The second winding head housing 7 comprises further housing elements (not shown) for enclosing the second winding head 5. The disc element 8 and the hollow body element 9 are designed as separate components. The disc element 8 and the hollow body element 9 are connected via a connection 10. In this case, the connection 10 is an adhesive bond. The first winding head housing 6 has a disc element 17 for collecting the coolant within the first winding head housing 6. The first winding head housing 6 further has a cylindrical hollow body element 18 for covering the first winding head 4 in a radial direction inwards. The disc element 17 and the hollow body element 18 are designed as separate components that are connected to each other via a connection 19. In this case, the connection 19 is an adhesive bond. To increase stiffness, the hollow body element 18 has a circumferential wall section 20.Further housing elements (not shown) of the first winding head housing 6 and the second winding head housing 7 can be attached via the threaded rod 22.

[0046] Figure 2 shows a disk element 8 and a hollow body element 9 of a second winding head housing 7. The hollow body element 9 has a plurality of rib elements 11 arranged on an outer surface 12. The hollow body element 9 also has a plurality of wall elements 13 arranged on the outer surface 12. Furthermore, the plurality of interfaces 14 are visible.

[0047] Figure 3 shows a detailed view of a first winding head housing 6. The connection 19 between the cylindrical hollow body element 18 and the disc element 17 has a stepped shape which is glued.

[0048] Figure 4 shows a further detailed view of a second winding head housing 7. It can be seen that one phase of the second winding head 5 is surrounded by two rib elements 11 and a wall element 13 to increase the creepage distance to another phase of the second winding head 5. A section of a housing element 23 for closing the second winding head housing 7 is also shown. The housing element 23 has a groove 25 designed to receive a seal for sealing the second winding head housing 7.

[0049] Figure 5 shows a further detailed view of a second winding head housing 7. In contrast to Figure 4, the simulated leakage currents 24 between two phases of the winding head 5 are shown here. Reference symbol

[0050] stator

[0051] Stator lamination stack, stator winding

[0052] first winding head, second winding head, first winding head housing, second winding head housing, disc element, hollow body element, connection, rib element, outer shell surface, wall element

[0053] first interface interior

[0054] second interface disc element hollow body element connection wall section cooling channel threaded rod housing element simulated leakage current

Claims

Claims 1. Stator (1) for an electric machine for a drive train for a vehicle, comprising a stator lamination stack (2), a stator winding (3), wherein the stator winding (3) comprises a first winding head (4) and a second winding head (5), a second winding head housing (7) for the second winding head (5), characterized by the fact that the second winding head housing (7) comprises a disc element (8) for distributing a cooling liquid within the second winding head housing (7), and wherein the second winding head housing (7) comprises a cylindrical hollow body element (9) for covering the second winding head (5) in a radial direction inwards, wherein the disk element (8) and the hollow body element (9) are designed as separate components which are connected to each other via a connection (10).

2. Stator (1) according to claim 1 , characterized by the fact that the cylindrical hollow body element (9) comprises at least one rib element (11) which is arranged in the axial longitudinal direction on an outer shell surface (12) of the hollow body element (9) to extend a creepage distance for a creepage current between two phases of the stator winding (3).

3. Stator (1 ) according to claim 1 or 2, characterized by the fact that the cylindrical hollow body element (9) comprises at least one wall element (13) which is arranged in the circumferential direction on an outer shell surface (12) of the hollow body element to extend a creepage distance for a creepage current between two phases of the stator winding (3).

4. Stator (1) according to any one of the preceding claims, characterized by the fact that the disk element (8) at least a first interface (14) for a coolant flow between the disk element (8) and an interior (15) of the second winding head housing (7), wherein the disk element (8) comprises at least a second interface (16) for a coolant flow between the disk element (8) and the stator lamination stack (2), and wherein the disk element (8) has at least one distribution channel which extends radially from the outside to the inside to connect the first interface (14) and the second interface (16).

5. Stator (1) according to any of the preceding claims, characterized by the fact that the stator (1 ) comprises a first winding head housing (6) for the first winding head (4), wherein the first winding head housing (6) comprises a disk element (17) for collecting the coolant within the first winding head housing (6), and wherein the first winding head housing (6) comprises a cylindrical hollow body element (18) for covering the first winding head (4) in a radial direction inwards, wherein the disk element (17) and the hollow body element (18) are designed as separate components which are connected to each other via a connection (19).

6. Stator (1) according to claim 5, characterized by the fact that the hollow body element (18) of the first winding head housing (6) has at least one wall section (20) extending at least partially circumferentially on an end face to increase stiffness and / or wherein the hollow body element (18) of the first winding head housing (6) has at least one rib element extending axially on its outer shell surface to increase stiffness.

7. Stator (1) according to any of the preceding claims, characterized by the fact that the stator lamination stack comprises at least one cooling channel (21), wherein the cooling fluid flows between the first winding head (4) through the at least one cooling channel (21) and the second winding head (5).

8. Stator (1 ) according to claim 1 or 5, characterized in that the connection (19, 10) of the first or second winding head housing (6, 7) comprises one or more of the following: adhesive connection, welded connection, screw connection, and / or the disc element (17, 8) and / or the hollow body element (18, 9) of the first or second winding head housing (6, 7) comprise a material of one or more of the following: PPA, PPS.

9. Electric machine with a stator (1) according to one of claims 1 to 8.

10. Drive train comprising a stator (1) according to one of claims 1 to 8 and / or an electric machine according to claim 9.

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