Rotor of an electric machine
Angling the pole shoe support slopes and optimizing locking element design in electrically excited synchronous machines reduces mechanical stress and deformation, allowing for higher rotational speeds and improved torque density.
Patent Information
- Application Number
- PCT/EP2025/067061
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-07-11
- Filing Date
- 2025-06-18
- Publication Date
- 2026-01-15
AI Technical Summary
Existing rotors of electrically excited synchronous machines face high mechanical stress and deformation of locking elements due to steep and short pole shoe support ramps, limiting maximum operating speed and requiring expensive materials, and result in a larger air gap and lower torque density.
The pole shoe support slopes are angled between 1 to 45 degrees, with locking elements having a head section supported on two pole shoes and foot sections parallel to the pole shaft, reducing mechanical stress and allowing for higher rotational speeds by using more cost-effective materials.
This design reduces mechanical stress and deformation, enabling higher rotational speeds and smaller air gaps while maintaining a high fill factor and torque density.
Smart Images
Figure EP2025067061_15012026_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] title
[0003] Rotor of an electric machine
[0004] State of the art
[0005] The invention relates to a rotor of an electrically excited synchronous machine according to the preamble of the main claim.
[0006] A rotor of an electrically excited synchronous machine is already known from DE102020200429 A1, comprising a rotor body rotatable about a rotor axis, in particular a rotor lamination stack, which has several salient poles arranged along a circumferential direction of the rotor, each comprising a pole shaft, a pole shoe arranged at the end of the pole shaft and each comprising a pole center axis extending radially with respect to the rotor axis, wherein the pole shafts are each enclosed by a single coil of an excitation winding of the rotor, wherein pole slots are formed between the salient poles in which the coil sides of two single coils are located, wherein the pole shoes each project into the respective adjacent pole slots, wherein the pole shoe of the respective salient pole has a coil support surface towards both pole slots for supporting the respective single coil, wherein a locking element is arranged in each of the pole slots.which is intended for closing the respective pole slot and is supported on two pole shoe support ramps. The pole shoe support ramps are formed at the opposing pole shoe ends of adjacent pole shoes. The pole shoe support ramps of the limb poles are comparatively steep and short, so that only a relatively small support area on the pole shoe can be achieved. This places high mechanical stress on the locking elements, necessitating the use of expensive plastics for their manufacture or limiting the maximum possible operating speed. Furthermore, comparatively steep pole shoe support ramps cause the locking elements, and consequently the excitation winding, to deform more radially, resulting in a larger required air gap and a lower torque density. Advantages of the invention,
[0007] In contrast, the rotor of an electrically excited synchronous machine according to the invention, with the characterizing features of the main claim, has the advantage that the mechanical stress and / or deformation of the locking elements is reduced, thus enabling a higher rotor speed. Furthermore, more cost-effective plastics can be used to manufacture the locking elements. Additionally, the deformation of the locking elements and the excitation winding under rotational load is reduced, thereby allowing for a smaller air gap.
[0008] This is achieved according to the invention by the pole shoe support slopes of the respective pole shoe having an oblique angle to the coil support surface, which lies in the range between one degree and 45 degrees, in particular between two degrees and 25 degrees.
[0009] The measures listed in the dependent claims enable advantageous further developments and improvements of the rotor of an electrically excited synchronous machine specified in the main claim.
[0010] It is particularly advantageous if the respective locking element has a head section for support against two pole shoes and a foot section extending towards the rotor axis, wherein the flanks of the head section facing the pole slot run parallel to a flank of the respective pole shaft. In this way, the coil sides of the individual coils can be designed as an orthocyclic winding, so that a high fill factor can be achieved in the respective pole slot. The coil sides of the individual coils are partially mechanically supported by the locking elements.
[0011] It is further advantageous if the head section of the respective locking element has two support ramps for bracing against the pole shoe support ramps of adjacent pole shoes, wherein each support ramp of the locking element is supported against the associated pole shoe support ramp without any overhang, particularly with respect to the radial direction. In this way, the locking elements are subjected only to compressive stress and not to shear stress, resulting in lower maximum stresses on the locking elements and thus enabling higher rotational speeds.
[0012] Furthermore, it is advantageous if the base section of the respective locking element has wall surfaces for supporting the coil sides of the respective pole slot, wherein the wall surfaces are particularly parallel to each other. In this way, the respective locking element can support not only the wires radially outer with respect to the rotor axis, but also the wires and layers located radially further inwards. The base section of the respective locking element can extend close to or to the bottom of the respective pole slot.
[0013] It is highly advantageous if the layers of each coil side are arranged orthocyclically on top of each other in the respective pole slot. This allows for a high fill factor in the respective pole slot.
[0014] It is also advantageous if the respective pole shoe support slope of the respective salient pole is located directly adjacent to the coil support surface of the pole shoe of the salient pole. In this way, a high fill factor can be achieved in the respective pole slot.
[0015] Furthermore, it is advantageous if the respective coil support surface of the respective salient pole comprises a straight support section towards the pole shoe support slope, which in particular runs perpendicular to the pole's central axis, and a kinked support section towards the pole shaft. In this way, a high strength of the salient pole can be achieved. The kinked support section can include at least a slope or at least a rounding, in particular a radius or spline.
[0016] Furthermore, it is advantageous if the angled support section includes a transition slope that has an oblique angle to the straight support section in the range between 25 and 35 degrees, particularly between 29 and 31 degrees. This further increases the strength of the limb pole. It also allows for a high fill factor in the respective pole groove.
[0017] It is advantageous if the angled support section towards the pole shaft includes a further transition slope that has an oblique angle to the transition slope, lying in the range between 25 and 35 degrees, particularly between 29 and 31 degrees. In this way, the strength of the limb pole can be increased even further.
[0018] Furthermore, it is advantageous if a star disk is arranged on each of the two end faces of the rotor body, each star disk having an annular section and several toothed sections projecting radially from the annular section with respect to the rotor axis to accommodate a winding head of the respective individual coil, and being particularly electrically insulating. A rotor sleeve, for example made of fiber-reinforced plastics, can be applied around the star disk.
[0019] It is further advantageous if the tooth sections of the respective star disk each have two opposing rounded edges for transitioning into the adjacent pole grooves, wherein at least on the two rounded edges at the radially outer end of the respective tooth section a step contour is formed to create a layer step, in which the last turn of the first layer is provided in a lower step plane and the first turn of the second layer in an upper step plane, wherein the first turn of the second layer is located at least one turn further radially outward than the last turn of the first layer, and wherein the layer step includes a ramp-shaped recess that forms a ramp for guiding the wire into the higher step plane. In this way, a wire crossing can be achieved for a layer jump that produces no or only a slight curvature or bulge in the upper layers of the individual coil.
[0020] In an advantageous embodiment, the winding heads of the excitation winding are each enclosed by a rotor sleeve, which also encloses the respective star disk. In this way, the centrifugal forces of each winding head of the excitation winding can be transferred into and absorbed by the rotor sleeve without mechanically overloading or damaging the star disk. The rotor sleeve can, for example, be made of fiber-reinforced plastics. This allows for higher rotational speeds. (Drawing)
[0021] An embodiment of the invention is shown in simplified form in the drawing and explained in more detail in the following description.
[0022] They show:
[0023] Fig. 1 shows a cross-section of a rotor of an electrically excited synchronous machine according to the invention.
[0024] Fig. 2 shows a section along line 11-11 in Fig. 1 ,
[0025] Fig. 3 shows detail A according to Fig. 1 in a first embodiment,
[0026] Fig. 4 shows detail A according to Fig. 1 according to a second embodiment,
[0027] Fig. 5 shows one of the star disks according to Fig. 1 and
[0028] Fig. 6 shows a tooth section of the star disk according to Fig. 5.
[0029] Description of the exemplary embodiment
[0030] Fig. 1 shows a cross-section of a rotor of an electrically excited synchronous machine according to the invention.
[0031] The rotor 1 of the electrically excited synchronous machine 2 comprises a rotor body 4 rotatable about a rotor axis 3, in particular a rotor lamination stack.
[0032] The synchronous machine 2 comprises the rotor 1 and a stator. In the radial direction with respect to the rotor axis 3, an air gap is formed between the stator and the rotor 1.
[0033] Fig. 2 shows a section along line 11-12 in Fig. 1.
[0034] The rotor body 4 has several salient poles 5 arranged along a circumferential direction of the rotor 1. Each salient pole 5 has a pole shaft 6, a pole shoe 7 arranged at the end of the pole shaft 6, and a pole center axis 8 extending radially with respect to the rotor axis 3. The pole shafts 6 are each enclosed by a single coil 9 of an excitation winding 10 of the rotor 1. Pole slots 12 are formed between each salient pole 5, in which the coil sides 9s of two single coils 9 are located. The pole shoes 7 of the salient pole 5 project into the adjacent pole slots 12 on both sides.
[0035] The flanks 6f of the respective polar shaft 6 run, for example, parallel to the polar axis 8. Alternatively, the flanks 6f of the respective polar shaft 6 could also run at an oblique angle to the polar axis 8.
[0036] The pole shoe 7 of each salient pole 5 has a coil support surface 13 facing both pole slots 12 for supporting the respective individual coil 9. A closing element 20 is arranged in each pole slot 12, designed to close the respective pole slot 12 and supported by two pole shoe support ramps 17 formed at the opposing pole shoe ends 7e of two adjacent pole shoes 7. The pole shoe support ramps 17 are each formed on an inner surface of the respective pole shoe 7 facing the respective pole slot 12.
[0037] The respective locking element 20 has a head section 21 supported on two pole shoes 7 and a foot section 22 extending towards the rotor axis 3. The flanks 21f of the head section 21 facing the pole groove 12 run, for example, parallel to a flank 6f of the respective pole shaft 6.
[0038] The foot section 22 of the respective closure element 20 has wall surfaces 22w for supporting the coil sides 9s of the respective pole groove 12, wherein the wall surfaces 22w in particular run parallel to each other.
[0039] The winding heads of the excitation winding 10 can each be enclosed by a rotor sleeve 35 according to Fig.1, which in particular also encloses the respective star disk 24.
[0040] Fig. 3 shows a detail A according to Fig. 1 according to a first embodiment.
[0041] According to the invention, the pole shoe support slopes 17 of each pole shoe 7 each have an inclined angle α to the coil support surface 13, which lies in the range between one degree and 45 degrees, in particular between two degrees and 25 degrees. The respective pole shoe support slope 17 of the respective salient pole 5 is, for example, provided directly adjacent to the coil support surface 13 of the pole shoe 7 of the salient pole 5.
[0042] The respective coil support surface 13 of the respective salient pole 5 comprises a straight support section 13L, which is provided towards the pole shoe support slope 17 and, in particular, runs perpendicular to the pole center axis 8, and a kinked support section 13B, which is provided towards the pole shaft 6 and kinks towards the pole shaft 6. According to Fig. 3 and Fig. 4, the kinked support section 13B can have at least one slope or, alternatively, at least one rounding, in particular a radius or spline.
[0043] According to Fig. 3, the angled support section 13B has, for example, a transition slope 14 which has an oblique angle β to the straight support section 13L in the range between 25 degrees and 35 degrees, in particular between 29 and 31 degrees. The respective transition slope 14 can transition with a rounded edge into the pole shaft 6 and / or with a rounded edge into the coil support surface 13 of the pole shoe 7.
[0044] According to Fig. 4, the angled support section 13B towards the pole shaft 6 has a further transition slope 15, which has an oblique angle y to the transition slope 14, which lies in the range between 25 degrees and 35 degrees, in particular between 29 and 31 degrees.
[0045] The head section 21 of the respective locking element 20 has two support ramps 21s for support against the pole shoe support ramps 17 of adjacent pole shoes 7, wherein each support ramp 21s of the locking element 20 is supported against the associated pole shoe support ramp 17 without any projection, particularly with respect to the radial direction. Thus, each support ramp 21s of the locking element 20 does not extend beyond the associated pole shoe support ramp 17 in the radial direction with respect to the rotor axis 3.
[0046] In the respective pole slot 12, the layers of the respective coil side 9s of the respective individual coil 9 are arranged orthocyclically one above the other. A slot insulation 16 can be provided in each pole slot 12, also between the pole shoe support slope 17 and the support slope 21s of the locking element 20.
[0047] Fig. 5 shows one of the star disks according to Fig. 1.
[0048] On the two end faces of the rotor body 4, a star disk 24 is arranged according to Fig. 1, which according to Fig. 5 has a ring section 25, several tooth sections 26 projecting radially from the ring section 25 with respect to the rotor axis 3 for receiving a winding head of the respective individual coil 9 and is designed to be electrically insulating, at least in sections, with regard to an electrical connection to be excluded between the excitation winding 10 and the rotor body 4.
[0049] Fig. 6 shows a tooth section of the star disk according to Fig. 5.
[0050] The tooth sections 26 of the respective star disk 24 each have two opposing rounded edges 27 for transitioning into the adjacent pole grooves 12. The rounded edges 27 of the tooth sections 26 can be grooved for wire guidance.
[0051] At the radially outer end of each tooth section 26, a step contour 30 is formed at least on the two rounded edges to create a layer step 31. On the layer step 31, the last turn of a first layer and the first turn of a second layer of the single coil 9 are provided in a lower step plane. The first turn of the second layer is located at least one turn further radially outward than the last turn of the first layer. The layer step 31 includes a ramp-shaped recess 32, which forms a ramp for guiding the wire into the higher step plane. The ramp-shaped recess 32 runs obliquely in the direction of the wire's extension to guide the last turn of the first layer into the first turn of the second layer.
Claims
Claims 1. Rotor (1) of an electrically excited synchronous machine (2) with a rotor body (4) rotatable about a rotor axis (3), in particular a rotor lamination stack, which has several salient poles (5) arranged along a circumferential direction of the rotor (1), each comprising a pole shaft (6), a pole shoe (7) arranged at the end of the pole shaft (6) and each a pole center axis (8) extending radially with respect to the rotor axis (3), wherein the pole shafts (6) are each enclosed by a single coil (9) of an excitation winding (10) of the rotor (1), wherein pole slots (12) are formed between the salient poles (5) in which the coil sides (9s) of two single coils (9) are located, wherein the pole shoes (7) each project into the respective adjacent pole slots (12), wherein the pole shoe (7) of the respective salient pole (5) has a coil support surface towards both pole slots (12). (13) for supporting the respective individual coil (9),wherein a closing element (20) is arranged in each of the pole grooves (12), which is provided for closing the respective pole groove (12) and is supported on two pole shoe support ramps (17) formed at the opposing pole shoe ends (7e) of adjacent pole shoes (7), characterized in that the pole shoe support ramps (17) of the respective pole shoe (7) each have an oblique angle (a) to the coil support surface (13), which lies in the range between one degree and 45 degrees, in particular between two degrees and 25 degrees.
2. Rotor according to claim 1, characterized in that the respective closure element (20) has a head section (21) for support on two pole shoes (7) and a foot section (22) extending towards the rotor axis, wherein the flanks (21 f) of the head section (21) facing the pole groove (12) extend in particular parallel to a flank (6f) of the respective pole shaft (6).
3. Rotor according to claim 2, characterized in that the head section (21) of the respective closure element (20) has two support ramps (21s) for support on the pole shoe support ramps (17) of adjacent pole shoes (7), wherein each support ramp (21s) of the closure element (20) is without projection, especially with regard to the radial direction, on the associated pole shoe support slope (17).
4. Rotor according to one of claims 2 or 3, characterized in that the foot section (22) of the respective closure element (20) has wall surfaces (22w) for supporting the coil sides (9s) of the respective pole slot (12), wherein the wall surfaces (22w) in particular run parallel to each other.
5. Rotor according to one of the preceding claims, characterized in that the positions of the respective coil side (9s) of the respective individual coil (9) lie orthocyclically on top of each other in the respective pole slot (12).
6. Rotor according to one of the preceding claims, characterized in that the respective pole shoe support slope (17) of the respective salient pole (5) is provided in direct connection with the coil support surface (13) of the pole shoe (7) of the salient pole (5).
7. Rotor according to one of the preceding claims, characterized in that the respective coil support surface (13) of the respective salient pole (5) comprises a straight support section (13L) towards the pole shoe support slope (17), which in particular runs perpendicular to the pole center axis (8), and a kinked support section (13B) towards the pole shaft (6).
8. Rotor according to claim 7, characterized in that the angled support section (13B) comprises a transition slope (14) which has an oblique angle (β) to the straight support section (13L) in the range between 25 degrees and 35 degrees, in particular between 29 and 31 degrees.
9. Rotor according to claim 8, characterized in that the bending support section (13B) towards the pole shaft (6) comprises a further transition slope (15) which has an oblique angle (y) to the transition slope (14) which is in the range between 25 degrees and 35 degrees, in particular between 29 and 31 degrees.
10. Rotor according to one of the preceding claims, characterized in that a star disk (24) is arranged on each of the two end faces of the rotor body (4), each of which has a ring section (25), several projections from the ring section (25) in a radial direction with respect to the rotor axis (3). tooth sections (26) for receiving each of a winding head of the respective individual coil (9) and is designed to be electrically insulating.
11. Rotor according to claim 10, characterized in that the tooth sections (26) of the respective star disk (24) each have two opposing rounded edges (27) for transitioning into the adjacent pole grooves (12), wherein at the radially outer end of the respective tooth section (26) at least on the two rounded edges (27) a step contour (30) is formed to form a layer step (31), on which in a lower step plane the last turn of a first layer and in an upper step plane the first turn of a second layer is provided, wherein the first turn of the second layer is located at least one turn further radially outward than the last turn of the first layer, wherein the layer step (31) comprises a ramp-shaped recess (32) which forms a ramp for guiding the wire into the higher step plane.
12. Rotor according to one of the preceding claims, characterized in that the winding heads of the excitation winding (10) are each enclosed by a rotor sleeve (35), which in particular encloses the respective star disk (24).
13. Electric machine (2) with a rotor (1) according to one of the preceding claims.