Stator of an electrical machine
The stator design in electric machines addresses inefficient cooling by integrating supply and yoke paths within the laminated core, enhancing cooling efficiency and reducing manufacturing costs through direct and jacket cooling of the stator yoke.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-02-07
- Publication Date
- 2026-03-17
AI Technical Summary
Existing stator designs in electric machines suffer from inefficient cooling, particularly of the stator yoke, which requires costly and labor-intensive manufacturing of cooling paths within the stator housing.
The stator design incorporates supply paths within the laminated core to directly supply refrigerant to stator slots and yoke paths, allowing for both direct and jacket cooling of the stator yoke, with various configurations of yoke passages and radial paths to enhance cooling efficiency and reduce manufacturing complexity.
This design improves cooling efficiency by eliminating the need for costly stator housing cooling paths, reduces manufacturing costs, and ensures uniform cooling of the stator yoke, while minimizing pressure loss and sealing requirements.
Smart Images
Figure 2026509239000001_ABST
Abstract
Description
Technical Field
[0001] The present invention starts from the stator of an electric machine based on the generic concept of claim 1.
Background Art
[0002] The stator of an electric machine is already known from DE102019113785A1 and comprises a stator shaft and a stator laminated core, in which stator teeth and stator slots between the stator teeth are formed. The stator laminated core includes a stator yoke connecting the stator teeth. The stator slots each extend in the radial direction with respect to the stator shaft between a slot bottom and a slot head. In each stator slot, there is provided a stack of only one conductor or a conductor bundle including a plurality of conductors, especially a stack of flat rectangular conductors, for forming an electrical stator coil. At least one slot gap is provided between the slot side surface of each stator slot and the conductor or conductor bundle arranged in the stator slot. The slot gap forms an axially extending slot gap path for direct cooling of the conductor, and the slot gap path can be traversed by a refrigerant along the slot cooling path.
Summary of the Invention
[0003] Advantages of the Invention In contrast, the stator according to the present invention of an electric machine having the features of claim 1 has the advantage that the cooling of the stator is further improved. Moreover, in addition to direct cooling of the conductor, jacket cooling of the stator yoke can be provided. Since the refrigerant is directly supplied through the stator yoke, the cooling path in the stator housing surrounding the stator, which has to be manufactured laboriously and at high cost, can be eliminated. Thereby, the manufacturing cost is reduced.
[0004] According to the present invention, - at least one supply path is formed in the stator laminated core, and this supply path leads to at least one of the stator slots respectively for supplying refrigerant to at least one slot cooling path. - Each supply path is connected by a radial path to the slot inlet of each stator slot, and upstream of the radial path is at least one yoke path, which runs axially within the stator yoke and is provided for cooling the stator yoke. It is achieved by doing so.
[0005] The measures described in the dependent claims enable advantageous deformation and improvement of the stator of the electromachine presented in claim 1. Particularly advantageous is the case where multiple yoke paths of at least one supply path are distributed around the outer circumference of the stator yoke and cause jacket cooling of the stator yoke. This ensures uniform cooling of the stator yoke across its outer circumference.
[0006] A further advantage is the case, based on the first exemplary embodiment, where multiple yoke passages are through passages, each passing completely through the stator laminated core in the axial direction, and each radial passage having at least one inlet, which is located, in particular, in the axial central region of the through passage or at the axial center. This allows the stator yoke to flow axially from end to end, thereby achieving uniform cooling of the stator yoke along the axial direction.
[0007] A significant advantage is the case, based on the second exemplary embodiment, where multiple yoke passages are short passages, which extend axially from at least one of the two end faces of the stator laminated core to the inlet of their respective radial passages, and are shorter than through passages, and in particular reach the axial central region of the stator laminated core.
[0008] In the first embodiment of the second exemplary embodiment, where only short-distance paths extending from only one end face of the stator laminated core are provided, partial jacket cooling of the stator yoke is achieved, covering only a portion of the axial direction of the stator yoke. This first embodiment is particularly simple and inexpensive to implement. In the second embodiment of the second exemplary embodiment, where short-distance paths extending from both end faces of the stator laminated core are provided, substantial full jacket cooling of the stator yoke, substantially covering the entire stator yoke, can be substantially achieved. However, the second embodiment of the second exemplary embodiment requires coolant supply from both end faces of the stator laminated core.
[0009] Based on a third exemplary embodiment, it is also advantageous that multiple pairs of yoke passages are provided and distributed around the outer circumference of the stator yoke, each pair of yoke passages extending from the same end face of the stator laminated core and adjacent in circumferential view, with one of each pair of yoke passages being a short passage and the other being a meandering passage, each meandering passage including a through section, a turning section and a short passage, and for each pair of yoke passages, the short passage and the short passage of the meandering passage are paired opposite each other and, in particular, located at the same circumferential position. This substantially achieves full jacket cooling of the stator yoke, which is advantageous because it substantially covers the entire stator yoke but requires coolant supply from only one of the two end faces of the stator laminated core.
[0010] A further advantage is when the meandering path reversal section according to the third exemplary embodiment is formed within the stator laminated core or within a reversal mechanism located at the end face of the stator laminated core. This allows for easy reversal of the meandering path. The reversal mechanism may be formed, for example, in the shape of a ring or a disc and may include all the meandering path reversal sections.
[0011] Furthermore, it is advantageous if a ring-shaped distribution channel is provided on at least one of the end faces of both ends of the stator laminated core, the distribution channel leading to the yoke channel and provided for supplying refrigerant to the supply path. This distribution channel distributes the refrigerant circumferentially to the yoke channel distributed over the outer circumference. This allows for a simple supply of refrigerant to the supply path.
[0012] It is advantageous to have two slot cooling paths running in opposite directions within each stator slot, and these slot cooling paths exit as free jets through slot outlets at the ends of each stator slot, particularly within the slot head or slot bottom. This simplifies the cooling paths within the stator with respect to the connection of the flow in the slot gaps or slot cooling paths. In particular, a ring-shaped collector is not required at the end face of the stator laminated core to collect the coolant coming out of the slot gaps, which may require sealing of the stator space to the rotor space of the electromechanical device, for example, using a sleeve or tube in the gap. Furthermore, the flow connection of the slot gaps according to the present invention allows for lower pressures in the cooling paths, thereby reducing the requirement for sealing of the slot gaps. In addition, since each cooling path runs only over a portion of the axial section of each stator slot rather than along its entire length, the pressure loss within each cooling path is reduced.
[0013] According to one advantageous embodiment, the radial path of each supply path is formed by a punched portion or recess in a single sheet metal of the stator laminated core, or by multiple radial path sections that are radially offset and partially overlapping in multiple adjacent sheet metals. This allows the radial path to be generated simply and inexpensively within the stator laminated core.
[0014] A further advantage is the case where, within each stator slot, multiple support points are formed, spaced apart from each other axially with respect to the stator axis, to clamp the conductor or conductor bundle within each stator slot, each of which is formed by the twisting of several or more sheets of metal in the stator laminated core, particularly by the twisting of one or more groups of sheets. This allows the support points to be generated without special sheets, and the conductor bundle can be inserted into the stator slot without clamping force during installation. This reduces the manufacturing cost of the stator. Moreover, damage to the conductor bundle is avoided when inserting it into each stator slot.
[0015] Several exemplary embodiments of the present invention are shown in the drawings and will be described in more detail below. [Brief explanation of the drawing]
[0016] [Figure 1] This is a partial side view of the stator according to the present invention. [Figure 2A] This is a cross-sectional view of the stator according to the present invention based on a first exemplary embodiment, when the stator is cut along line II-II in Figure 1. [Figure 2B] Multiple linear development views of the stator yoke path according to the present invention according to Figure 1, according to a first exemplary embodiment according to Figure 2A. [Figure 3A] This is a cross-sectional view of the stator according to the present invention, based on a second exemplary embodiment, when the stator is cut along line II-II in Figure 1. [Figure 3B] Multiple linear development views of the stator yoke path according to the present invention according to Figure 1, according to a second exemplary embodiment according to Figure 3A. [Figure 4A] Here are several linear development views of a stator yoke path according to the present invention, based on Figure 1, according to a third exemplary embodiment. [Figure 4B] This is a first cross-sectional view of the stator according to the present invention, according to a third exemplary embodiment based on Figure 4A, when the stator is cut along line IV-IV in Figure 4A. [Figure 4C] FIG. 2 is a second cross-sectional view of a stator according to the present invention according to a third exemplary embodiment based on FIG. 4A when the stator is cut along line V-V of FIG. 4A. [Figure 5A] FIG. 5 is a view showing an embodiment of a first thin metal plate provided with a path section for generating a radial path in a stator laminated core. [Figure 5B] FIG. 6 is a view showing an embodiment of a second thin metal plate provided with a path section for generating a radial path in a stator laminated core. [Figure 5C] FIG. 7 is a view showing arrangements of first and second thin metal plates based on FIGS. 5A and 5B for generating a radial path in a stator laminated core. [Figure 6] FIG. 8 is a view showing a slot cross-section along line VI-VI of FIG. 2A. [[ID=http: / / www.example.com / 15]] [Figure 7] FIG. 9 is a view showing a slot cross-section along line VII-VII of FIG. 2A. [Figure 8] FIG. 10 is a view showing a slot cross-section along line VIII-VIII of FIG. 2A. [Figure 9] FIG. 11 is a cross-sectional view of one of the stator slots of a stator according to the present invention having a conductor bundle supported at a plurality of support points. [Figure 10] FIG. 12 is a partial view of a stator according to the present invention having a twisted thin metal plate for generating a support point for a conductor bundle. DETAILED DESCRIPTION OF THE INVENTION
[0017] FIG. 1 shows a side view of a part of a stator according to the present invention. The stator 1 according to the present invention of the electromechanical machine 2 has a stator axis 3 and includes a stator laminated core 4 in which stator teeth 5 and stator slots between the stator teeth 6 are formed, and the stator laminated core 4 includes a stator yoke 7 connecting the stator teeth 5. The stator slots 6 each extend in the radial direction with respect to the stator axis 3 between a slot bottom 6g and a slot head 6h, and may each have a slot slit in the slot head 6h.
[0018] Within each stator slot 6, there is provided a single electrical conductor 8, or a bundle of conductors 9 containing multiple conductors 8, particularly a stack of flat wire conductors, to form an electrical stator coil 10.
[0019] At least one slot gap 12 is provided between the slot side surface 6f of each stator slot 6 and the conductor 8 or conductor bundle 9 arranged within the stator slot 6, and the slot gap 12 forms a slot gap passage 13 that extends axially with respect to the stator axis 3, and the slot gap passage 13 can be passed through by a coolant along the slot cooling path 14.
[0020] Figure 2A shows a cross-sectional view of the stator according to the present invention based on a first exemplary embodiment, where the stator is cut along line II-II in Figure 1. The stator laminated core 4 is formed by a stack of thin sheet metal 16.
[0021] Within each stator slot 6, two slot cooling paths 14 running in opposite directions are provided, and these slot cooling paths 14 exit as free jets through slot outlets 14.2 at the ends of each stator slot 6, particularly within the slot head 6h or within the slot bottom 6g.
[0022] The stator slots 6 may be closed by at least one slot cap 19 to seal the slot cooling path 14. The slot caps can be generated by fabricating a single sleeve-shaped or tubular slot cap as an independent element to close all the slot slits 6s, for example, according to Figures 1 and 6 to 8. According to a second embodiment (not shown), a thin plate-shaped slot cap, in particular a slot liner, may be provided as an independent element within each slot slit 6s. According to a third embodiment (not shown), each slot cap 19 can be formed by a tooth tip bridge portion, which is part of a thin sheet metal 16 and connects the tooth tips of adjacent stator teeth 5 and, in particular, has reduced magnetic permeability.
[0023] According to the present invention, at least one supply path 15 is formed within the stator laminated core 4, and each of these supply paths 15 is intended to lead to at least one of the stator slots 6 in order to supply coolant to at least one slot cooling path 14.
[0024] Furthermore, according to the present invention, each supply path 15 is connected to the slot inlet 14.1 of each stator slot 6 by a radial path 15.1 that runs radially, and upstream of the radial path 15.1 is at least one yoke path 15.2 which runs axially within the stator yoke 7 and is intended to be provided for cooling the stator yoke 7.
[0025] Figure 2B shows a linear development view of multiple stator yoke paths according to the present invention according to Figure 1, according to a first exemplary embodiment according to Figure 2A. For example, multiple yoke paths 15.2 of at least one supply path 15 are distributed around the outer circumference of the stator yoke 7, thereby causing jacket cooling within the stator yoke 7.
[0026] According to the first exemplary embodiment, a plurality of yoke passages 15.2 are formed as through passages 23, each passing completely through the stator laminated core 4 in the axial direction, and each radial passage 15.1 has at least one inlet 17. The inlet 17 is located, for example, in the axial central region of the through passage 23, particularly in the axial center.
[0027] Ring-shaped distribution passages 20 can be placed on both end faces of the stator laminated core 4, and these distribution passages 20 are connected to the respective yoke passages 15.2 and are provided for supplying refrigerant to the supply passage 15.
[0028] Figure 3A shows a cross-sectional view of the stator according to the present invention based on a second exemplary embodiment, where the stator is cut along line II-II in Figure 1. Figure 3B shows a plurality of stator yoke paths according to the present invention according to Figure 1, according to a second exemplary embodiment according to Figure 3A, in linear development views.
[0029] According to a second exemplary embodiment, a plurality of yoke passages 15.2 are formed as short passages 24, which extend axially from at least one of the two end faces of the stator laminated core 4 to the inlet of their respective radial passages, and are formed to be shorter than the through passages 23, and in particular reach the axial central region of the stator laminated core 4.
[0030] According to a first embodiment (not shown) of the second exemplary embodiment, only short-distance paths 24 extending from only one of the two end faces of the stator laminated core 4 may be provided, thereby achieving partial jacket cooling that covers only a portion of the axial direction of the stator yoke 7. According to a second embodiment shown in Figures 3A and 3B of the second exemplary embodiment, short-distance paths 24 extending from both end faces of the stator laminated core 4 may be provided. This second embodiment achieves full jacket cooling that substantially covers the entire stator yoke 7. With respect to the second embodiment, ring-shaped distribution paths 20 may be provided on each end face of the stator laminated core 4, leading to their respective yoke paths 15.2 and provided for supplying coolant to the supply path 15.
[0031] Short-distance paths 24 extending from one end face of the stator laminated core 4 and short-distance paths 24 extending from the other end face are, for example, paired and aligned with respect to their circumferential position, and are particularly positioned facing each other as a pair, or as a pair at the same circumferential position.
[0032] Figure 4A shows a linear development view of multiple stator yoke paths according to the present invention based on Figure 1, according to a third exemplary embodiment. Figure 4B shows a first cross-sectional view of the stator according to the present invention, according to a third exemplary embodiment based on Figure 4A, when the stator is cut along line IV-IV in Figure 4A.
[0033] Figure 4C shows a second cross-sectional view of the stator according to the present invention, according to a third exemplary embodiment based on Figure 4A, when the stator is cut along line VV in Figure 4A. According to a third exemplary embodiment, a plurality of pairs 15.2p of yoke paths 15.2 of different lengths are provided and distributed around the outer circumference of the stator yoke 7. Each pair 15.2p of yoke paths 15.2 extends from the same end face of the stator laminated core 4 and is adjacent to one another in the circumferential direction, with one side of each pair 15.2p being a short-distance path 24 and the other side being a meandering path 25, the meandering path 25 including a through section 25.1, a reversal section 25.2, and a short-distance section 25.3. A ring-shaped distribution path 20 may be provided at the end face of the stator laminated core 4 where the yoke paths 15.2 begin, and which leads to each yoke path 15.2 and is provided for supplying coolant to the supply path 15.
[0034] For each pair 15.2p of York Route 15.2, the short-distance route 24 and the short-distance section 25.3 of the meandering route 25 are paired and facing each other, and are particularly positioned at the same circumferential location.
[0035] In this way, the third exemplary embodiment achieves full jacket cooling that substantially covers the entire stator yoke 7. The direction-changing section 25.2 of the meandering path 25 may be formed within a direction-changing mechanism 26 located at the end face of the stator laminated core 4, as shown in Figure 4A, or within the stator laminated core 4 in a configuration not shown. The direction-changing mechanism 26 may be formed, for example, in the shape of a ring or a disc, and may include all the direction-changing sections of the meandering path.
[0036] Figure 5A shows one embodiment of a first sheet metal having a path section for generating radial paths within a stator laminated core. Figure 5B shows an embodiment of a second sheet metal having a path section for generating radial paths within a stator laminated core.
[0037] Figure 5C shows the arrangement of the first and second sheet metals based on Figures 5A and 5B for generating radial paths within the stator laminated core. The radial paths 15.1 of each supply path 15 can be formed in various ways. As shown in Figures 5A to 5C, the radial path 15.1 can be formed by a plurality of radial path sections 18, which are fabricated radially offset within a plurality of adjacent sheet metals 16 and partially overlap radially.
[0038] Alternatively, the radial path 15.1 can also be generated, for example, by a punched portion or recess in a single sheet metal 16 of the stator laminated core 4. Figure 6 shows a slot cross-section along line VI-VI in Figure 2A, Figure 7 shows a slot cross-section along line VII-VII in Figure 2A, and Figure 8 shows a slot cross-section along line VIII-VIII in Figure 2A.
[0039] Figure 9 shows a partial view of the stator according to the present invention, which includes a twisted slender plate for generating support points for the conductor bundle. Within each stator slot 6, a plurality of support points 11 are formed, spaced apart from each other axially with respect to the stator shaft 3, to clamp and hold the conductors 8 or conductor bundles 9 within each stator slot 6. As shown in Figure 10, each support point 11 may be formed by the twisting of several or more sheet metal 16 of the stator laminated core 4, particularly by the twisting of one or more groups 28 of sheet metal 16. These twisted sheet metal 16 are twisted (in opposite directions) with respect to the other sheet metal 16 of the stator laminated core 4, for example, at a specific twist angle φ around the stator shaft 3, in order to form one of the support points 11. Each support point 11 is formed by two groups 28 of sheet metal 16 that are twisted in opposite directions with respect to a specific twist angle φ around the stator shaft 3, for example. Between the support points 11 according to the present invention, the conductors 8 or conductor bundles 9 of each stator slot 6 are suspended in mid-air, that is, they do not come into contact with the stator laminated core 4. In other words, each conductor 8 or conductor bundle 9 of the stator slot 6 is in contact with the stator laminated iron core 4 only at the support points 11.
[0040] Each slot cooling path 14 is narrowed at least at the support points 11. Therefore, one bypass 21 is provided at each support point 11, thereby guiding the refrigerant to pass alongside each narrowed support point 11. In this case, the bypass 21 of each stator slot 6 is formed, for example, alternately within the slot bottom 6g or within the slot head 6h along each slot cooling path 14 from each slot inlet 14.1 (Figures 2A, 6, and 8), thereby creating a meandering trajectory for the slot cooling path 14.
[0041] As shown in Figure 6, each bypass 21 within the slot base 6g may be formed, for example, by one or two notches in the slot side surface 6f at the root of the stator tooth 5, or by one notch in the slot base 6g.
[0042] As shown in Figures 2A, 6, and 8, each slot cap 19 has a plurality of axially spaced sealing portions 22 to create a meandering slot cooling path 14 for each stator slot 6. These sealing portions 22 extend, in particular, to or near the conductor 8 or conductor bundle 9.
[0043] Between adjacent sealing portions 22 of the same stator slot 6, axially running passages are provided as bypasses 21 for the respective slot cooling paths. Figures 6 and 7 show one of the sealing portions 22 of each slot cap 19.
Claims
1. A stator for an electric machine (2), comprising a stator shaft (3) and a stator laminated core (4), wherein the stator laminated core (4) has stator teeth (5) and stator slots (6) between the stator teeth (5), and the stator laminated core (4) includes a stator yoke (7) connecting the stator teeth (5), wherein the stator slots (6) extend radially with respect to the stator shaft (3) between a slot bottom (6g) and a slot head (6h), and electric stator coils (10) are formed within each of the stator slots (6). In a stator, a single conductor (8) or a bundle of conductors (9) including multiple conductors (8), particularly a stack of flat wire conductors, is provided, and at least one slot gap (12) is provided between the slot side surface (6f) of each of the stator slots (6) and the conductor (8) or bundle of conductors (9) arranged within the stator slot (6), the slot gap (12) forms a slot gap passage (13) extending in the axial direction, and the slot gap passage (13) can be passed through by a coolant along a slot cooling path (14), - At least one supply path (15) is formed within the stator laminated core (4), and the supply path (15) is connected to at least one of the stator slots (6) in order to supply refrigerant to at least one slot cooling path (14), A stator characterized in that each of the supply paths (15) is connected by a radial path (15.1) to a slot inlet (14.1) of each of the stator slots (6), and upstream of the radial path (15.1) is at least one yoke path (15.2), the yoke path (15.2) runs axially within the stator yoke (7) and is provided for cooling the stator yoke (7).
2. The stator according to claim 1, characterized in that a plurality of yoke passages (15.2) of at least one of the supply passages (15) are distributed over the outer circumference of the stator yoke (7) and cause jacket cooling of the stator yoke (7).
3. The stator according to claim 2, characterized in that a plurality of the yoke passages (15.2) are through passages (23), each through passage (23) completely passes through the stator laminated core (4) in the axial direction, and each radial passage (15.1) has at least one inlet (17), the inlet (17) being located in the axial central region of the through passage (15.2) or in the axial center.
4. The stator according to claim 2, characterized in that a plurality of the yoke passages (15.2) are short passages (24), and the short passages (24) extend axially from at least one of the end faces of the stator laminated core (4) to the inlet (17) in each of the radial passages (15.1), and are shorter than the through passages (23), and in particular reach the axial central region of the stator laminated core (4).
5. The stator according to claim 4, wherein a plurality of pairs (15.2p) of yoke paths (15.2) are provided and distributed over the outer circumference of the stator yoke (7), and the yoke paths (15.2) of each pair (15.2p) extend from the same end face of the stator laminated core (4) and are adjacent in the circumferential direction, and one of the yoke paths (15.2) of each pair (15.2p) is a short-distance path (24) and the other of the yoke path (15.2) is a meandering path (25), and each meandering path (25) includes a through section (25.1), a direction-changing section (25.2), and a short-distance section (25.3), and with respect to each pair (15.2p) of yoke paths (15.2), the short-distance path (24) and the short-distance section (25.3) of the meandering path (25) are paired and facing each other, and in particular are arranged at the same circumferential position.
6. The stator according to claim 5, characterized in that the direction-changing section (25.2) of the meandering path (25) is formed within the stator laminated core (4) or within a direction-changing mechanism (26) disposed at the end face of the stator laminated core (4).
7. A stator according to any one of claims 1 to 6, characterized in that a ring-shaped distribution passage (20) is arranged on at least one of the end faces of the stator laminated iron core (4), the distribution passage (20) is connected to the yoke passage (15.2), and is provided for supplying refrigerant to the supply passage (15).
8. A stator according to any one of claims 1 to 7, characterized in that two slot cooling paths (14) running in opposite directions are provided within each of the stator slots (6), and the slot cooling paths (14) exit as free jets through slot outlets (14.2) at the end of each of the stator slots (6), particularly within the slot head (6h) or within the slot bottom (6g).
9. The stator according to any one of claims 1 to 8, characterized in that the radial path (15.1) of each of the supply paths (15) is formed by a punched portion or recess in only one sheet metal (16) of the stator laminated core (4), or by a plurality of radial path sections (18) that are radially offset and partially overlapping in a plurality of adjacent sheet metals (16).
10. The stator according to any one of claims 1 to 9, characterized in that the stator slot (6) is closed by at least one slot cap (19) to seal the slot cooling path (14).
11. A stator according to any one of claims 1 to 10, wherein each of the stator slots (6) has a plurality of support points (11) that are spaced apart from each other in the axial direction with respect to the stator shaft (3), and the support points (11) are formed to clamp the conductor (8) or conductor bundle (9) located in each of the stator slots (6), and each of the support points (11) is formed by the twisting of some or more thin sheet metal (16) of the stator laminated core (4), in particular by the twisting of one or more groups (28) of thin sheet metal (16).
12. An electric machine (2) comprising a stator (1) according to any one of claims 1 to 11.