ELECTRIC MEDIA GAP MACHINE FOR A COMPRESSOR AND/OR TURBINE, COMPRESSOR AND/OR TURBINE

Abstract

The invention relates to an electric media gap machine (10) for a compressor (2) and/or a turbine (3), in particular for a turbocharger (1) of an internal combustion engine, comprising a shaft (5) which is rotatably mounted in a housing (6) and to which a rotor (11) is rotationally fixed, a stator (12) which is fixed to the housing and which has at least one multiphase drive winding (16) for generating a drive magnetic field and multiple stator teeth (15) which protrude inwards radially. Each stator tooth (15) has a tooth base (29) paired with a stator yoke (12) and a free end (28) facing the rotor (11). The end (28) of at least multiple stator teeth (15), in particular of all of the stator teeth (15), is axially offset to the tooth base (29) of the same stator tooth (15).

Claims

1-10. (canceled)

11. A compressor (2) and/or turbine (3) comprising a housing (6), a shaft (5) which is rotatably mounted in the housing (6) and on which at least one compressor wheel (4) or turbine wheel (7) is co-rotationally arranged, and comprising an electric media gap machine (10) having a rotor (11) co-rotationally arranged on the shaft (5) and a stator (12) fixed to the housing, the stator having at least one multiphase drive winding (16) for generating a drive magnetic field, and multiple stator teeth (15) which protrude radially inwards, wherein each stator tooth (15) has a tooth base (29) paired with a stator yoke (12) and a free end (28) facing the rotor (11), wherein the free ends (28) of at least several stator teeth (15) are arranged to be offset axially relative to the tooth base (29) of the same stator tooth (15), wherein the free ends (28) of the at least several stator teeth (15) are arranged to be offset axially in a direction of the compressor wheel (4) or the turbine wheel (7).

12. The compressor and/or turbine as claimed in claim 11, wherein each respective stator tooth (15) of the at least several stator teeth (15) has, at least in some sections, a curvature (30) for the axially offset arrangement of the end (28) relative to the tooth base (29).

13. The compressor and/or turbine as claimed in claim 11, wherein each respective stator tooth (15) of the at least several stator teeth (15) has, at least in some sections, a shear (30) for the axially offset arrangement of the end (28) relative to the tooth base (29).

14. The compressor and/or turbine as claimed in claim 11, wherein the at least several stator teeth (15) each have a basic tooth (15) and a flux guide element (15) adjoining the basic tooth (15).

15. The compressor and/or turbine as claimed in claim 14, wherein each respective stator tooth (15) of the at least several stator teeth (15) has, at least in some sections, a curvature (30) for the axially offset arrangement of the end (28) relative to the tooth base (29), and wherein the curvature (30) is formed in the transition from the basic tooth (15) to the flux guide element (15), in the basic tooth (15) or in the flux guide element (15).

16. The compressor and/or turbine as claimed in claim 14, wherein the curvature (30) of the respective stator tooth (15) extends along the respective flux guide element (15).

17. The compressor and/or turbine as claimed in claim 11, wherein the offset ends (28) of the stator teeth (15) are offset equally far axially.

18. The compressor and/or turbine as claimed in claim 11, wherein an axial length of the at least several stator teeth (15) is constant or changes in a radial extent of the respective stator tooth (15).

19. An exhaust-gas turbocharger (1), comprising a housing (6), a shaft (5) which is rotatably mounted in the housing (6) and on which at least one compressor wheel (4) or turbine wheel (7) is co-rotationally arranged, and comprising an electric media gap machine (10) having a rotor (11) co-rotationally arranged on the shaft (5) and a stator (12) fixed to the housing, the stator having at least one multiphase drive winding (16) for generating a drive magnetic field, and multiple stator teeth (15) which protrude radially inwards, wherein each stator tooth (15) has a tooth base (29) paired with a stator yoke (12) and a free end (28) facing the rotor (11), wherein the free ends (28) of all the stator teeth (15) are arranged to be offset axially relative to the tooth base (29) of the same stator tooth (15), wherein the free ends (28) of the at least several stator teeth (15) are arranged to be offset axially in a direction of the compressor wheel (4) or the turbine wheel (7).

20. The exhaust-gas turbocharger as claimed in claim 19, wherein each respective stator tooth (15) of the at least several stator teeth (15) has, at least in some sections, a curvature (30) for the axially offset arrangement of the end (28) relative to the tooth base (29).

21. The exhaust-gas turbocharger as claimed in claim 19, wherein each respective stator tooth (15) of the at least several stator teeth (15) has, at least in some sections, a shear (30) for the axially offset arrangement of the end (28) relative to the tooth base (29).

22. The exhaust-gas turbocharger as claimed in claim 19, wherein the at least several stator teeth (15) each have a basic tooth (15) and a flux guide element (15) adjoining the basic tooth (15).

23. The exhaust-gas turbocharger as claimed in claim 22, wherein each respective stator tooth (15) of the at least several stator teeth (15) has, at least in some sections, a curvature (30) for the axially offset arrangement of the end (28) relative to the tooth base (29), and wherein the curvature (30) is formed in the transition from the basic tooth (15) to the flux guide element (15), in the basic tooth (15) or in the flux guide element (15).

24. The exhaust-gas turbocharger as claimed in claim 22, wherein the curvature (30) of the respective stator tooth (15) extends along the respective flux guide element (15).

25. The exhaust-gas turbocharger as claimed in claim 19, wherein the offset ends (28) of the stator teeth (15) are offset equally far axially.

26. The exhaust-gas turbocharger as claimed in claim 19, wherein an axial length of the at least several stator teeth (15) is constant or changes in a radial extent of the respective stator tooth (15).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention is to be explained in more detail below by using the drawings, in which

[0016] FIG. 1 shows an exhaust gas turbocharger with an integrated media gap machine in a simplified sectional illustration,

[0017] FIG. 2 shows a cross-sectional illustration through the media gap machine, and

[0018] FIG. 3 shows a design variant of the media gap machine in a detailed view.

DETAILED DESCRIPTION

[0019] FIG. 1 shows, in a simplified longitudinal sectional illustration, an exhaust-gas turbocharger 1, which has a compressor 2 and a turbine 3. The compressor 2 has a compressor wheel 4, which is co-rotationally arranged on a shaft 5. The shaft 5 is itself rotatably mounted in a housing 6 of the exhaust-gas turbocharger 1. At an end of the shaft 5 that faces away from the compressor wheel 4, a turbine wheel 7 of the turbine 3 is additionally co-rotationally connected to the shaft 5. When exhaust gas from an internal combustion engine flows into the turbine wheel 7 and the latter is driven as a result, the compressor wheel 4 is therefore likewise set into a rotational movement, so that fresh air fed to the compressor wheel 4 is compressed and fed to the internal combustion engine.

[0020] The rotatable mounting of the shaft 5 in the housing 6 can be implemented in different ways. According to a first exemplary embodiment, provision is made for the shaft 5 to be rotatably mounted in the housing 6 by at least two bearings 8 and 9. Preferably, two rolling element bearings are present as bearings 8, 9. For the axial mounting of the shaft 5, provision can also be made for one of the rolling element bearings to be formed as an axial rolling element bearing.

[0021] Alternatively and according to the exemplary embodiment shown in FIG. 1, provision is made for the bearing 8 to be formed as a magnetic bearing and for the bearing 9, which serves as an axial bearing, to be formed as a rolling element bearing.

[0022] In order in particular that the compressor 2 can be driven independently of the exhaust gas stream from the internal combustion engine, so that a high cylinder air filling to the cylinders of the internal combustion engine can be achieved at any time, provision is additionally made in the present case for the exhaust-gas turbocharger 1 to have an electric media gap machine 10. In the present case, this is integrated into the compressor 2, a rotor 11 of the media gap machine 10 being co-rotationally arranged on the end of the shaft 5 that faces away from the turbine wheel 7. A stator 12 interacting with the rotor 11 is arranged coaxially relative to the rotor 11 and fixed to the housing in the flow channel 13 of the exhaust-gas turbocharger 1 that leads to the compressor wheel 4.

[0023] FIG. 2 shows a perspective sectional illustration of the media gap machine 10 for better understanding. The stator 12 has a circular stator yoke 14 on which a plurality of stator teeth 15 arranged uniformly over the circumference of the stator yoke 14 protrude radially inwards and point in the direction of the rotor 11 and of the axis of rotation of the shaft 5. The stator teeth 15 end radially at a distance from the rotor 12, so that an air gap remains between the stator teeth 15 and the rotor 12. In the present case, the stator teeth have a base section 15 paired with the stator yoke 14 and a flux guide element 15 which lengthens the base section 15 and the free end of which is paired with the rotor 11.

[0024] The stator 12 is provided with an in particular multiphase drive winding 16, which is formed from multiple flat conductor coils 17 wound around the stator teeth 15. At the front ends of the stator 12, the flat conductor coils 17 each form a winding head 18 and 19, which projects axially beyond the stator teeth 15 and the stator yoke 14.

[0025] In the present case, the compressor 2 has a flow volute 22 paired with the impeller or compressor wheel 4. The flow volute 22 is formed by the housing 6 and projects axially beyond the compressor wheel 4 in the direction of the media gap machine 10, as shown in particular in FIG. 1. The installation space for the winding 19 in the housing 6 is delimited axially by the flow volute 22.

[0026] As shown in FIG. 2, the flat conductor coils 17 are arranged with a radial height H from an outer circumference 23 as far as an inner circumference 24, advantageously between the stator yoke 14 and an outer sleeve 25, which, radially on the outside, delimits a flow path 26 for the medium, in particular the fresh air, leading through the media gap machine 10. The outer sleeve 25 is pierced by the stator teeth 15, in particular by the flux guide elements 15 thereof.

[0027] Coaxially relative to the outer sleeve 25, an inner sleeve 27 is arranged within the outer sleeve 25 and is paired with the rotor 11 but located at a distance from the latter. The stator teeth 15 extend with their flux guide elements 15 at least as far as the inner sleeve 27 or penetrate the latter, so that they extend through the entire interspace between outer sleeve 25 and inner sleeve 27. The inner sleeve 27 delimits the flow path 26 radially on the inside and is preferably closed on its front side located upstream of the rotor 11 by a covering cap, so that the medium which is guided through the media gap machine 10 is guided only through the flow path 26 between inner sleeve 27 and outer sleeve 25. Because the flow path 26 is thus led through the stator 12 and the medium flows around the stator teeth 15, at least the flux guide elements 15, the stator 12 and the rotor 11 are advantageously cooled by the medium. Optionally, the outer sleeve 25 has a corresponding number of stator teeth 15 and holding devices for holding and locking the flat conductor coils 17, so that these are/can be preassembled on the outer sleeve 25 and form a pre-assembly unit together with the outer sleeve 25. Optionally, the inner sleeve 27 is additionally connected to the outer sleeve 25, in particular formed in one piece with the latter, in order to form a compact unit or pre-assembly group. In particular, for example, radial webs are provided between the inner sleeve 27 and the outer sleeve 25, by means of which the one-piece formation is ensured. The radial webs are in particular formed in such a way as to accommodate one of the flux conductor elements 15 each and to surround the latter, so that a compact and simple arrangement and orientation of the pre-assembly unit on the stator 12 is achieved.

[0028] As can be seen in FIG. 1, the flux guide elements 15 are formed in the shape of a parallelogram by a shear 30, so that an end 28 of the respective stator tooth 15 that faces the rotor 11 is offset axially relative to the stator yoke 14 and to a tooth base 29 of the respective stator tooth 15 that faces the stator yoke. In the present case, all stator teeth 15 are formed in a corresponding way, so that the ends 28 of the stator teeth 15 are offset axially with respect to the stator yoke 14 in the direction of the compressor wheel 4. As a result, the rotor 11 is arranged axially particularly close to the compressor wheel 4 on the shaft 5, so that the distance of the rotor 11 from the bearing 8 is shortened. Therefore, the oscillatory behavior of the shaft 5 at the end having the rotor 11 is improved, and the operating behavior of the exhaust-gas turbocharger 1 is optimized overall.

[0029] According to the present exemplary embodiment, because of the parallelogram-like configuration of the flux guide elements 15, a virtually abrupt transition between the non-sheared region in the basic teeth 15 and the sheared region in the flux guide elements 15 is formed, which in this transition represents a curvature of the respective stator teeth 15 with a very small radius, which leads to the ends 28 being arranged and aligned to be offset axially relative to the tooth bases 29. In other words, the stator teeth 15 are sheared in the direction of the compressor wheel 4, starting from the transition from basic tooth 15 to flux guide element 15.

[0030] In a laminated design of the stator 12, this is achieved in particular in that each stator lamination is bent in a press before the joining of the individual stator laminations to form the stator 12 or to form a stator tooth 15. The bending is carried out in the present exemplary embodiment in such a way that each stator lamination is bent or angled over in the region of the flux guide piece 15 in accordance with the virtually abrupt transition. After that, the joining to form an overall stator tooth 15 with yoke part and stator yoke 14 and flux guide piece 15 is carried out. Alternatively, the stator lamination pack can also be joined from still un-bent or not angled-over laminations, and the bending or turning over can then be carried out on the entire lamination pack. Baking with baking lacquer and repeated machining, in which the respective flux guide piece is given a final outer contour benefiting flow, is preferably carried out subsequently.

[0031] FIG. 3 shows a further exemplary embodiment of the media gap machine by using a detailed view of one of the stator teeth 15. As an alternative to the previously described exemplary embodiment, instead of the shear 30, a curvature 30 is provided, which extends along the flux guide element 15. While, in the preceding exemplary embodiment, there is a bend in the transition region, according to the present exemplary embodiment a bending line with the curvature 30 is provided, which has a considerably greater constant or variable radius and which extends along the entire flux guide piece 15. As a result, a leading edge 31 that faces away from the compressor wheel 4 and a trailing edge 32 of the flux guide element 15 that faces the compressor wheel 4 are formed so as to be curved, as can be seen in FIG. 3.

[0032] It transpires that, as a result of both variants described, the rotor 11 can be arranged closer to the compressor wheel 4 and therefore to the closest bearing 8. As a result, the risk of the occurrence of flexural oscillation, which could lead to overloading or overstressing of rotor 11 and/or shaft 5, is reduced considerably.

[0033] As an alternative to the design of the stator 12 from multiple stator laminations, according to a further exemplary embodiment provision is made for the stator 12 or the stator teeth 15 to be made from solid material or from a powder composite material. In this case, it would also be possible to make geometries in which the axial length of the respective stator tooth in its radial extent is not constant but varies. In this way, for example, optimal adaptation of the respective stator tooth to the existing installation space can be achieved.

[0034] The start of the shear or of the curvature does not necessarily have to be located at the transition between the basic tooth 15 and flux guide element 15 as in the present exemplary embodiments, but can also be located radially at a distance from this transition within the basic tooth 15 or the flux guide element 15.