Stator having a cooling channel structure extending obliquely to an axial direction, and electric machine

Abstract

The invention relates to a stator (1) for an electric machine (10), comprising an annular main body (3), which is formed from a plurality of stacked metal sheets (2), and a coil assembly (4), some sections of which are accommodated in the main body (3), wherein a cooling channel structure (6), at least some sections of which extend obliquely to an axial direction, is present in or on the main body (3), and wherein the cooling channel structure (6) has at least one cooling channel (8) extending continuously in the axial direction, and this at least one cooling channel (8) is in turn formed from a plurality of interconnected through-holes in the main body (3). The invention further relates to an electric machine (10) comprising this stator (1).

Description

[0001] Stator with cooling channel structure running obliquely to an axial direction; and electrical machine

[0002] The invention relates to a stator for an electrical machine, in particular a drive motor of a motor vehicle, comprising an annular base body formed of / composed of a plurality of stacked laminations / individual laminations and a coil arrangement partially accommodated in the base body. A cooling channel structure extending at least partially obliquely to an axial direction (i.e., a direction parallel to / along a longitudinal axis of the stator) is present in or on the base body, preferably on an outer side of the base body. Furthermore, the invention relates to an electrical machine having this stator.

[0003] Stators of this type for electrical machines are already well known in the prior art. For example, DE 102021 114 546 A1 discloses an electrical machine with a stator and a housing, wherein the housing has a coolant inlet and a coolant outlet for conducting coolant through a gap between a stator base body and the housing.

[0004] Stators are already known that have cooling channels on the outside to dissipate the waste heat generated during operation of the electric motor. However, there is a fundamental need to make the cooling even more efficient.

[0005] It is therefore an object of the present invention to provide a stator which has a further improved efficiency, wherein its structure should be kept as simple as possible.

[0006] This is achieved according to the invention in that the cooling channel structure has at least one cooling channel running continuously in the axial direction, and the at least one cooling channel is in turn formed by a plurality of interconnected through holes in the base body. Additionally, it is disclosed how the cooling channel is formed on the base body by a plurality of interconnected recesses that are introduced radially from the outside into the individual sheets.

[0007] By creating recesses in the laminations, the cooling channel structure is integrated directly into the components already present in the base body, without the need for additional components. Combined with the partially axially inclined course of each cooling channel, this creates increased flow resistance, so that the cooling fluid is distributed as evenly as possible in the circumferential direction on the axial end face of the stator, which serves as the supply, thus cooling the stator as evenly as possible in the circumferential direction.

[0008] Further advantageous embodiments are claimed in the subclaims and explained in more detail below.

[0009] For a further optimized guidance of the cooling fluid, it has also proven advantageous if the cooling channel runs in a serpentine / zigzag shape in the axial direction.

[0010] If several cooling channels are provided / integrated into the base body distributed in the circumferential direction, even more even heat dissipation is achieved.

[0011] For a simpler design of the stator, it is also beneficial if the cooling channels are separated from each other in the circumferential direction by elevations formed directly on the sheets.

[0012] It is also advantageous if the cooling channel structure has several groups of cooling channels that differ in terms of their specific properties, each of which is located in a circular arc segment of the base body. This allows the cooling channel structure to be adjusted as variably as possible depending on the application area of ​​the electrical machine. It is therefore also expedient if the groups differ from one another in terms of the number and / or shape of their cooling channels. Alternatively, the cooling channels in the groups can also be designed with the same shape and number, but differ in their position relative to an interlacing angle of the stacks / lamination stacks / individual laminations.

[0013] The cooling capacity can be adjusted as variably as possible if there are between two and eight circular arc segment sections, which together form the continuous outer side of the base body.

[0014] If the cooling channel structure has two collecting chambers running in the circumferential direction, each provided or arranged on a front side of the base body and directly connected to the cooling channels, the cooling channel structure is easy to form. This makes the stator as simple to manufacture as possible.

[0015] The stator's design is further simplified if the cooling channels are directly enclosed / enclosed in the radial direction by a sleeve-shaped / annular housing component. However, the cooling channels do not necessarily need to be enclosed by the housing if they are completely embedded in the stator / base body.

[0016] Furthermore, the invention relates to an electric machine for a motor vehicle, having a stator according to the invention according to at least one of the previously described embodiments and a rotor arranged radially inside the stator.

[0017] The invention will now be explained in more detail below with reference to figures, in which context various embodiments are also indicated.

[0018] They show:

[0019] Fig. 1 is a perspective detailed view of a stator according to a

[0020] Embodiment, wherein a radial outer side of a base body of the stator can be seen in more detail in the region of several cooling channels of a cooling channel structure arranged next to one another in the circumferential direction,

[0021] Fig. 2 is a perspective view of the stator according to Fig. 1 with a housing component enclosing the cooling channels radially from the outside,

[0022] Fig. 3 is a highly simplified front view of the stator according to Fig. 1, showing a subdivision of the cooling channel structure into several circular arc segment sections, each having a specific number and shape of cooling channels, wherein in the first embodiment a total of six circular arc segment sections are present,

[0023] Fig. 4 is a highly simplified front view of a stator according to a second embodiment, wherein four circular arc segment sections are now present, each having different numbers and shapes of cooling channels, and

[0024] Figs. 5a to 5h show various diagrams for the schematic representation of differently shaped cooling channels as can be introduced into the stator according to the invention, wherein channel sections positioned in different ways in the circumferential direction, each in one of the twelve existing individual sheets of the base body, are designated with “channel 1”, “channel 2”, “channel 3” or “channel 4”.

[0025] The figures are merely schematic and serve solely to clarify the invention. The same elements are designated by the same reference numerals.

[0026] In conjunction with Figs. 1 and 2, an overall annular / hollow-cylindrical stator 1 can be clearly seen by way of example. The stator 1 is preferably used in operation in an electrical machine 10 indicated in Fig. 2. In addition to the stator 1, the electrical machine 10 has, in the usual way, a rotor 16 arranged radially within the stator 1 and rotatable relative to the stator 1. An axis of rotation of the rotor 16, which simultaneously corresponds to a longitudinal axis of the stator 1, is provided with the reference numeral 18.

[0027] The directions used in the present case are related to the axis of rotation 18, so that the term axial / axial direction is understood to mean a direction along / parallel to the axis of rotation 18, the term radial / radial direction is understood to mean a direction perpendicular to the axis of rotation 18, and the term circumferential direction is understood to mean a direction along a circular line concentrically encircling the axis of rotation 18.

[0028] In Figs. 1 and 2, a more detailed illustration of a coil arrangement 4 arranged in a likewise annular base body 3 of the stator 1 is omitted. However, it can be seen that the base body 3 has a plurality of grooves 17 distributed in the circumferential direction, which, in the fully assembled state of the stator 1, each accommodate a plurality of radially stacked / radially superimposed longitudinal sections of the coil arrangement 4. Winding heads / winding head regions of the coil arrangement 4 are then arranged at the respective axial end faces 13a, 13b of the base body 3. The individual longitudinal sections of the coil arrangement 4 are interconnected / connected to one another at these winding heads / winding head regions.

[0029] The base body 3 itself is formed from a laminated core and therefore comprises several stacked laminations 2. In the first embodiment, for example, twelve laminations 2 are present, forming the base body 3.

[0030] According to the invention, the stator 1 is equipped with a cooling channel structure 6. This cooling channel structure 6 is part of a cooling device for cooling the stator 1 during operation of the electric machine 10. This cooling device typically comprises a pump and further lines connecting the pump to the cooling channel structure 6.

[0031] The cooling channel structure 6 serves to transport cooling fluid / liquid in the axial direction through the base body 3. The cooling channel structure 6 has a plurality of cooling channels 8 distributed in the circumferential direction, which run continuously from a first end face 13a to a second end face 13b of the base body 3. The cooling fluid is collected / accumulated approximately at the first end face 13a (in a first collecting chamber 14a) and from there conveyed into the individual cooling channels 8. At the second end face 13b, the cooling fluid exits the cooling channels 8 again and is collected in a second collecting chamber 14b, from where it is conveyed back to the pump / reservoir. The collecting chambers 14a, 14b, which are sealed from the environment, thus serve to collect and distribute the cooling fluid in the circumferential direction. In Fig. 1, these cooling channels 8 are formed, by way of example, on the radial outer side of the base body 3.This serves as a practical explanation for cooling channels formed in the base body 3 itself, which are formed by a plurality of interconnected through holes in the base body 3. When cooling channels 8 are shown and explained here and below on the radial outer side of the base body 3, this simultaneously serves to explain and describe cooling channels formed by a plurality of interconnected through holes in the base body 3.

[0032] It can also be seen that the cooling channel structure 6 is formed by a plurality of depressions 7 introduced from the radial outside, i.e. on a radial outer side 5 of the base body 3 (in the respective metal sheets 2). Each depression 7 forms an axial passage in a metal sheet 2. A plurality of depressions 7 arranged axially next to one another, which partially overlap in the circumferential direction, form a cooling channel 8. On each circumferential side, the depressions 7 are delimited by elevations 9 of the metal sheets 2. The depressions 7 (of the various metal sheets 2) are arranged and aligned relative to one another in such a way that a cooling channel 8 which is essentially zigzag-shaped / serpentine in the axial direction is produced.

[0033] The cooling channels 8 can be formed in different ways, but have at least two sections that run obliquely to one another and to the axial direction. In this regard, particular reference is made to Figs. 5a to 5h. The terms "channel 1", "channel 2", "channel 3" and "channel 4" identify different channel sections that are formed by the respective recess 7 and are arranged at the corresponding position in the circumferential direction. The individual sheets 2 forming the base body 3 are numbered 1 to 12 according to their axial sequence. This makes it possible to provide the cooling channels 8 with more than one change of direction. The cooling channel structure 6 implemented in Fig. 1 is shown in Fig. 5a.

[0034] In connection with Figs. 3 and 4, it should also be noted that the cooling channel structure 6 can be divided into a plurality of groups 11a to 11f of cooling channels 8. These groups 11a to 11f are distributed across a plurality of circular arc segment sections 12a to 12f of the base body 3, with each group 11a to 11f being assigned to a separate circular arc segment section 12a to 12f. In the first exemplary embodiment, approximately six such circular arc segment sections 12a to 12f are present; however, in further embodiments, as indicated in Fig. 4, for example, it is also possible to provide fewer or more than six, here four, circular arc segment sections 12a to 12f. In total, between two and eight circular arc segment sections 12a to 12f are preferably provided. As can be seen in Fig. 1, circular arc segment sections 12a to 12f are separated from one another, for example by means of an exclusively axially extending intermediate channel 19.

[0035] In conjunction with Fig. 4, it is also evident that the cooling channels 8 of the individual groups 11a to 11f differ from one another in terms of their number and shape. It is also possible, in principle, to design several groups 11a to 11f with the same cooling channels 8. The cooling channels 8 of a group 11a to 11f are identical to one another and run parallel to one another. However, the cooling channels 8 of a group 11a to 11f can also be designed differently.

[0036] While Figs. 3 and 4 show the design of the cooling channels 8 on the radial outer side, this is also intended to explicitly describe and explain the distribution of the cooling channels, the number of groups 11a to 11f, and their shape for cooling channels formed by several interconnected through holes in the base body 3. Radially outwardly, the cooling channel structure 6 is closed off by an annular housing component 15, visible in Fig. 2, wherein the individual cooling channels 8 are only open in the axial direction toward the end faces 13a, 13b and are further connected to the collecting channels 14a, 14b.

[0037] In other words, according to the invention, the channels (cooling channels 8) have a zigzag pattern / course, which significantly increases the pressure loss in the axial direction (cooling function). Due to the higher pressure loss, the distribution in the antechamber (collection chamber 14a; area in which the oil / cooling fluid is distributed around the circumference in front of the stator 1) is significantly more homogeneous, and the oil is better distributed among the channels / oil channels. This applies in particular to cooling channels formed by several interconnected through holes in the base body 3.

[0038] The zigzag channels are generated by forming six segments (circular arc segment sections 12a to 12f), each with an angle of 60°, on the outer diameter of the stator laminations (laminations 2). Each segment contains several slots (recesses 7) or projections (elevations 9) in or between which the channels form. The channels in the six segments are distributed in such a way that zigzag channels (cooling channels 8) are formed when the laminations 2, or individual stacks, are stacked in a twisted manner.

[0039] In the preferred embodiment, there are three different geometries that repeat.

[0040] The channels can be designed as closed slots, or only as noses on the stator outer diameter, which only form closed channels with the housing (housing component 15).

[0041] Thus, a stator 1 is implemented that has cooling channels 8 that run not straight, but in a zigzag pattern. The cooling channels 8 are formed on at least three sides (at least on two circumferential sides and one radial side) by the stator 1 / base body 3 itself. If necessary, the outer area of ​​the channels is formed by the housing. The stator 1 can be designed with several segments in which different cooling channels 8 are punched. The zigzag channels are created by stacking the segments in a twisted manner.

[0042] The illustrations in Figures 5a to 5h show a few examples of two to four channels / channel sections (channels 1 to 4) (positioned at different circumferential positions) with twelve axial sections each. However, many more variants are conceivable.

[0043] Preferably, 2 to 8 segments are distributed around the circumference (preferably 6 segments). With 6 segments, for example, each segment has an angle of 60°.

[0044] Within these segments, there are 2 to 8 different cooling channels (preferably three different ones). It is preferable if it is a divisor of the number of segments: for example, with 6 segments: 2, 3, 6 different segments.

[0045] Within the segments / groups 11 a to 11 f, 2 to 10 individual channels are formed (preferably 6 channels).

[0046] The channels are preferably all identical within a segment. However, the channels can also be different within a segment. For example, (seen circumferentially) they may be different in the center than at the edges.

[0047] There are channels with zigzags and also without, i.e., channels that run exclusively axially. This can be useful for optimizing the sheets 2 for punching. In this case, a straight channel without zigzags can be used in the area of ​​the coil edges and, if necessary, at the contact points of the blanks in the coil. To the left and right of this, narrower channels with zigzags are used.

[0048] There is at least one deflection (bend) in the cooling channels 8. Several turning points are better. The goal is for all stack positions to occur equally often so that the flatness (height) is correct in the end. This means that, if possible, all segments occur equally often in one position. In Figures 5a to 5h, they are designated as channel 1, 2, 3, 4... The channels are preferably completely bounded by the stator 1, except for the axial inlets and outlets. The channels are more preferably partially bounded by the stator 1 and at least on one side by the housing.

[0049] According to further embodiments, the cooling channels are thus also formed by a plurality of interconnected through holes (penetrating the respective sheet metal) in the base body. The above-mentioned and described configurations expressly also apply to these cooling channels, which are formed by a plurality of interconnected through holes in the base body 3.

[0050] List of reference symbols Stator Sheet metal Base body Coil arrangement Outside Cooling channel structure Recess Cooling channel Elevation Electric machine a first group b second group c third group d fourth group e fifth group f sixth group a first circular arc segment section b second circular arc segment section c third circular arc segment section d fourth circular arc segment section e fifth circular arc segment section f sixth circular arc segment section a first end face b second end face a first collecting chamber b second collecting chamber Housing component Rotor Groove Axis of rotation Intermediate channel

Claims

Patent claims 1. Stator (1) for an electrical machine (10), with an annular base body (3) formed from a plurality of stacked laminations (2) and a coil arrangement (4) partially accommodated in the base body (3), wherein in or on the base body (3) there is a cooling channel structure (6) which runs at least partially obliquely to an axial direction, characterized in that the cooling channel structure (6) has at least one cooling channel (8) which runs continuously in the axial direction and this at least one cooling channel (8) is in turn formed by a plurality of interconnected through holes in the base body (3).

2. Stator (1) according to claim 1, characterized in that the at least one cooling channel (8) runs serpentine as a whole in the axial direction.

3. Stator (1) according to claim 1 or 2, characterized in that several cooling channels (8) are provided distributed in the circumferential direction.

4. Stator (1) according to claim 3, characterized in that the cooling channels (8) are separated from one another in the circumferential direction by elevations (9) formed directly on the sheets (2).

5. Stator (1) according to one of claims 1 to 4, characterized in that the cooling channel structure (6) has a plurality of groups (11 a, 11 b, 11 c, 11 d) of cooling channels (8) which differ in terms of their specific properties, which groups (11 a, 11 b, 11 c, 11 d) are each introduced into a circular arc segment section (12a, 12b, 12c, 12d) of the base body (3).

6. Stator (1) according to claim 5, characterized in that the groups (11 a, 11 b, 11 c, 11 d) differ from one another with regard to the number and / or shape of their cooling channels (8).

7. Stator (1 ) according to claim 5 or 6, characterized in that between two and eight circular arc segment sections (12a, 12b, 12c, 12d) are present which together form the continuous outer side (5) of the base body (3).

8. Stator (1) according to one of claims 1 to 7, characterized in that the cooling channel structure (6) has two collecting spaces (14a, 14b) extending in the circumferential direction, each provided to an end face (13a, 13b) of the base body (3), which are directly connected to the cooling channels (8).

9. Electrical machine (10) for a motor vehicle, with a stator (1) according to one of claims 1 to 8 and a rotor (16) arranged radially inside the stator (1).

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