Stator for an electric machine, electric machine, drive train

Abstract

The invention relates to a stator (1) for an electric machine, comprising a winding head (2) and a winding head housing (3), wherein the winding head housing (3) at least partially encloses the winding head (2) from its surroundings, characterized in that the stator (1) comprises a cylindrical hollow body (4) arranged between the winding head (2) and the winding head housing (3), and wherein the cylindrical hollow body (4) is configured to conduct a coolant flow over its outer surface (5) and supply it to the winding head (4) for cooling. The invention further relates to an electric machine with such a stator (1) and a drive train with such a stator (1).

Description

[0001] The invention relates to a stator for an electric machine, comprising a winding head, a winding head housing, wherein the winding head housing at least partially encloses the winding head from an environment, an electric machine with such a stator, and a drive train with such a stator.

[0002] Stators for electric machines, such as electric motors, are well-known in the art. The slots of these stators are usually cooled. For this purpose, the winding heads are enclosed. Coolant is introduced into a first winding head via an interface and from there directed to the slot to cool the stator winding, before being discharged via the second winding head. It has been found that this method of supply does not allow for a homogeneous distribution of coolant within the first winding head. Consequently, cooling within the stator slot is insufficient.

[0003] In this context, it has become apparent that there is a need to provide a stator for an electric machine, in particular a need to provide an improved stator for an electric machine.

[0004] 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. In particular, it is an object of the present invention to provide an improved stator for an electric machine.

[0005] This problem is solved according to the invention in a stator of the generic type by the fact that the stator comprises a cylindrical hollow body which is arranged between the winding head and the winding head housing, and wherein the cylindrical hollow body is configured to guide a coolant flow over its outer surface and supply it to the winding head for cooling. In particular, the problem is solved by a stator with the features of independent claim 1.

[0006] Furthermore, the problem is solved by an electric machine having the features of independent claim 8 and by a drive train having the features of independent claim 9.

[0007] 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.

[0008] A first aspect of the present invention relates to a stator for an electric machine, comprising a winding head, a winding head housing, wherein the winding head housing at least partially encloses the winding head from an environment, characterized in that the stator comprises a cylindrical hollow body arranged between the winding head and the winding head housing, and wherein the cylindrical hollow body is arranged to guide a coolant over its outer surface and supply it to the winding head for cooling.

[0009] The term winding head refers to a section of the coil winding that is located outside the laminated core unit or the magnetic core and connects the active winding wires of the coil winding in the slots of the stator, thus creating a closed electrical circuit.

[0010] In this context, the stator refers to a stationary component used to generate a magnetic field that interacts with the rotor of the electric machine. In AC motors, the stator is typically equipped with coil windings through which an alternating current flows. This current generates a rotating magnetic field that drives the rotor.

[0011] 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.

[0012] The term winding head housing refers to a structural enclosure for protecting the winding head from its environment. The winding head housing may be made of plastic. It may be a single piece or a multi-piece housing. It may also be an injection-molded component. The winding head housing may be designed to be connected to a stator, either directly or indirectly.

[0013] The term "cylindrical hollow body" refers to a structural component designed to be positioned radially between the winding head and the winding head housing. It distributes a coolant across its outer surface and supplies it to the winding head for cooling. The cylindrical hollow body acts as a distribution ring for the coolant. The coolant can be pumped in a cooling circuit. For example, the coolant can be introduced at a point on the circumference, and the cylindrical hollow body distributes this coolant around its circumference, then supplies it evenly to the winding head. The cylindrical hollow body can have channels extending axially and / or circumferentially to guide the coolant. The cylindrical hollow body can be made of plastic or metal.The cylindrical hollow body can be a single piece. The cylindrical hollow body can be multi-piece. The cylindrical hollow body can have an axial extension length configured to at least partially overlap the winding head. The cylindrical hollow body can be configured to overlap the winding head axially by at least one of the following amounts around the circumference of the winding head: 1 / 3 to 1 / 2, 1 / 3 to 2 / 3, 1 / 2 to 2 / 3.

[0014] The invention is based on the understanding that stators require cooling. Cooling is achieved via the winding heads, which serve as the inlet and outlet for the coolant. However, the supply of coolant to the winding head is insufficient because the coolant is not distributed adequately. This results in inhomogeneous and inefficient cooling. Furthermore, the installation space, particularly the axial space, is limited in electrical machines such as electric motors in vehicle powertrains. To overcome these problems, the invention proposes the arrangement of a cylindrical hollow body between the winding head and the winding head housing to optimally distribute the incoming coolant within the winding head. The cylindrical hollow body does not increase the axial installation space and enables a uniform coolant supply around the circumference.This allows for homogeneous coolant distribution and cooling while maintaining a compact design.

[0015] Advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

[0016] According to a preferred embodiment, the cylindrical hollow body and the winding head housing can form at least one channel on the outer shell surface, which extends in an axial direction of the cylindrical hollow body and is configured to facilitate a coolant flow in the axial direction.

[0017] In this context, the term "channel" refers to a supply channel arranged axially on the cylindrical hollow body, which directs the coolant to the winding head. The channel can be formed, for example, by a groove in the cylindrical hollow body. The channel can be formed, for example, by a groove in the winding head housing. The channel can be formed, for example, by two corresponding grooves in the cylindrical hollow body and the winding head housing.

[0018] The cylindrical hollow body and the winding head housing can, for example, be arranged at least partially one above the other in such a way that a coolant can only be conveyed to the winding head via the channel. Preferably, the cylindrical hollow body and the winding head housing can form a multitude of channels for the coolant flow.

[0019] This allows for targeted coolant supply.

[0020] According to a preferred embodiment, the winding head housing can include at least one coolant inlet for the coolant flow, wherein the at least one coolant inlet is arranged on a lateral surface of the winding head housing and / or on an end face of the winding head housing.

[0021] A coolant inlet on a surface of the winding head housing can be easily manufactured. The coolant inlet can be designed as an inlet nozzle.

[0022] A coolant inlet on one end face of the winding head housing can enable a compact stator design.

[0023] According to a preferred embodiment, the stator can comprise at least one coolant supply channel within a stator lamination stack and / or a stator housing, which is connected to the at least one coolant inlet at the end face of the winding head housing.

[0024] By arranging the coolant supply channel within the stator lamination stack and / or the stator housing, the stator can be advantageously cooled even on its way to the winding head.

[0025] According to a preferred embodiment, the winding head housing and / or the cylindrical hollow body can include at least one distribution channel for the coolant flow extending partially in the circumferential direction, which is fluidically connected to the at least one channel.

[0026] The distribution channel allows the coolant to be distributed around the circumference of the cylindrical hollow body. The channels, in turn, enable the coolant to be directed precisely to the winding head.

[0027] This allows for improved distribution of the coolant and thus better overall cooling.

[0028] According to a preferred embodiment, the stator can have at least one coolant inlet for the coolant flow via the outer shell surface, wherein the at least one channel comprises a plurality of channels distributed over a circumference of the cylindrical hollow body, and wherein the cross-section of a channel of the plurality of channels increases with increasing distance in a circumferential direction from the at least one coolant inlet, thus enabling a uniform distribution of the coolant.

[0029] The flow resistance decreases with increasing cross-section. If all channels had the same flow resistance, an uneven distribution would result. By adjusting the flow resistance, particularly by reducing it in more distant channels, a uniform coolant supply can be achieved. Preferably, the winding head housing and the cylindrical hollow body can have positive-locking corresponding connection interfaces, for example, a fork element and counterpart, which enable directional assembly or arrangement and prevent incorrect assembly. This provides anti-rotation protection. This can have a beneficial effect on the quality of the stator.

[0030] According to a preferred embodiment, the winding head housing can have at least one collar and the cylindrical hollow body can have at least one corresponding recess for arranging and centering the cylindrical hollow body within the winding head housing.

[0031] In this way, the cylindrical hollow body can be easily arranged in a form-fitting or force-fitting manner.

[0032] This allows for efficient centering and alignment of the cylindrical hollow body. This can have a beneficial effect on stator cooling. For example, an uneven temperature distribution exists within the stator, requiring a correspondingly adjusted coolant supply. Cooling can be optimized through appropriate channel arrangement and alignment across the flanges and recesses.

[0033] Another aspect of the present invention relates to an electric machine with a stator described in more detail above.

[0034] Another aspect of the present invention relates to a drive train comprising a stator and / or an electric motor described above.

[0035] The invention is explained below with the aid of a drawing. The drawing shows: Fig. 1 a stator according to the invention, Fig. 2 a section of a stator according to the invention, Fig. 3 a winding head housing according to the invention, Fig. 4 a cylindrical hollow body according to the invention Fig. 5 a stator according to the invention, Fig. 6 a stator according to the invention, and Fig. 7 a winding head housing according to the invention.

[0036] Identical elements are provided with the same reference numerals. Features of the individual embodiments can be interchanged, complement each other, or replace each other.

[0037] Fig. Figure 1 shows a stator 1 according to the invention. The stator 1 comprises a winding head 2. The winding head 2 is at least enclosed by a winding head housing 3. The winding head housing 3 is connected to a plastic overmolding 17 of the stator 1. The winding head housing 3 has a coolant inlet 7 on its outer surface 8. A cylindrical hollow body 4 is arranged between the winding head 2 and the winding head housing 3. The cylindrical hollow body 4 has a circumferentially extending distribution channel 13 on its outer surface 5. The cylindrical hollow body 4 has one or a plurality of axially extending channels 6, which are fluidically connected to the distribution channel 13. A coolant can flow into the distribution channel 13 via the coolant inlet 7 and distribute itself there over the circumference of the cylindrical hollow body 4 and flow out to the winding head 2 via the channels 6.

[0038] Fig. Figure 2 shows a section of a stator 1 according to the invention. The cylindrical hollow body 4 has a recess 15. The winding head housing 3 has a collar 14 that engages in the recess 15 to arrange the cylindrical hollow body in a form-fitting manner within the winding head housing 3.

[0039] Fig. Figure 3 shows a winding head housing 3 according to the invention. The winding head housing 3 comprises a plurality of frets 14 for arranging and centering the cylindrical hollow body 14.

[0040] Fig. 4 a cylindrical hollow body 4 according to the invention. The cylindrical hollow body 4 comprises a plurality of channels 6. The cross-sections of the channels 6 increase clockwise. The cylindrical hollow body 4 includes fork elements 16 for preventing rotation. The winding head housing 3 has corresponding counterparts (not shown).

[0041] Fig. Figure 5 shows a stator 1 according to the invention. In contrast to Fig. In this case, the stator 1 has a coolant supply channel 10, which is formed by the laminated core 11 and the stator housing 12. The coolant inlet 7 is located on the end face 9 of the winding head housing 3. The coolant supply channel 10 is fluidically connected to the coolant inlet 7. The distribution channel 13 is formed by the winding head housing 3, the stator housing 12, and the plastic overmolding 17.

[0042] Fig. 6 a stator 1 according to the invention. In comparison to Fig. Figure 5 shows a connecting channel 18 between distribution channel 13 and channel 6, which is formed by the plastic overmolding 17 and the winding head housing 3.

[0043] Fig. 7 a winding head housing 3 according to the invention with contours for the connecting channel 18. Reference symbol list 1 Stator 2 winding heads 3 winding head housings 4 cylindrical hollow bodies 5 Outer shell area 6-channel 7 Coolant inlet 8 Surface area 9 Front 10 Coolant supply channel 11 Stator lamination package 12 Stator housings 13 distribution channel 14th Federal State 15 recess 16 Fork element 17 Plastic overmolding 18 connection channel

Claims

[1] Stator (1) for an electric machine, comprising a winding head (2), a winding head housing (3), wherein the winding head housing (3) at least partially encloses the winding head (2) from its surroundings, characterized by , that the stator (1) comprises a cylindrical hollow body (4) which is arranged between the winding head (2) and the winding head housing (3), and wherein the cylindrical hollow body (4) is arranged to guide a coolant over its outer shell surface (5) and supply it to the winding head (2) for cooling. [2] Stator (1) according to claim 1, characterized by , that the cylindrical hollow body (4) and the winding head housing (3) form at least one channel (6) on the outer shell surface (5) which extends in an axial direction of the cylindrical hollow body (4) and is designed to facilitate a coolant flow in the axial direction. [3] Stator (1) according to claim 1 or 2, characterized by , that the winding head housing (3) includes at least one coolant inlet (7) for the coolant flow, wherein at least one coolant inlet (7) is arranged on a shell surface (8) and / or on an end face (9) of the winding head housing (3). [4] Stator (1) according to claim 3, characterized by , that the stator (1) comprises at least one coolant supply channel (10) within a stator lamination stack (11) and / or a stator housing (12) which is connected to the at least one coolant inlet (7) on the end face (9) of the winding head housing (3). [5] Stator (1) according to any of the preceding claims, characterized by , that the winding head housing (3) and / or the cylindrical hollow body (4) comprise at least one distribution channel (13) extending partially in the circumferential direction for the coolant flow, which is fluidically connected to the at least one channel (6). [6] Stator (1) according to any of the preceding claims, characterized by , that the stator (1) has at least one coolant inlet (7) for the coolant flow over the outer shell surface (5), wherein the at least one channel (6) comprises a plurality of channels (6) distributed over a circumference of the cylindrical hollow body (4), and wherein a cross-section of a channel (6) of the plurality of channels (6) increases with increasing distance in a circumferential direction from the at least one coolant inlet (7), so that a uniform distribution of the coolant is enabled. [7] Stator (1) according to any of the preceding claims, characterized by , that the winding head housing (3) has at least one collar (14) and the cylindrical hollow body (4) has at least one corresponding recess (15) for arranging and centering the cylindrical hollow body (4) within the winding head housing (3). [8] Electric machine with stator according to any one of claims 1 to 7. [9] Drive train with a stator (1) according to any one of claims 1 to 7 and / or an electric machine according to claim 8.

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