ELECTRIC DRIVE MACHINE FOR A COMPRESSOR AND / OR A TURBINE

Description

State of the art

[0001] Various electric drive motors and turbochargers are known from the prior art. For example, DE 10 2014 210 451 A1 discloses a turbocharger with an integrated electric drive motor. Turbochargers, especially exhaust gas turbochargers, are used primarily in automotive engineering to increase the air volume in the cylinders of an internal combustion engine in order to increase the engine's power output. Exhaust gas turbochargers, which are driven by the exhaust gas flow of the internal combustion engine, are frequently used for this purpose.

[0002] Furthermore, it is known to provide electric motor assistance to a turbocharger, allowing fresh air drawn in from the internal combustion engine to be compressed and supplied to the engine at increased boost pressure, independent of the exhaust gas flow. A combination of both approaches is also known. In this case, an exhaust gas turbocharger is equipped with an electric drive motor to power the turbocharger shaft, on which a compressor wheel and a turbine wheel are fixed. This can, for example, significantly accelerate the otherwise delayed build-up of boost pressure.

[0003] Such an electric drive motor typically comprises a stator, which has at least one multi-phase drive winding to generate a drive magnetic field, and a rotor. The rotor has a permanent magnet and is mounted non-rotatably on the shaft of the exhaust gas turbocharger. Implementing the electric motor assistance with an electric drive motor has the advantage that the motor assistance can be integrated into the turbocharger in a particularly space-saving manner. By energizing the phases of the drive winding using dedicated power electronics, the rotating drive magnetic field is generated, which drives the rotor, which is rotatably mounted on the shaft, with a predefined torque. The permanent magnet interacts with the rotating magnetic field.

[0004] Despite the advantages offered by existing electric drive motors, there is still room for improvement. For example, increasing the compressor's efficiency to boost the turbocharger's efficiency and improve the overall system efficiency remains a challenge.

[0005] From FR 3 048 022 A1, a compressor with an electric drive motor is known, wherein the electric drive motor comprises a rotor and a stator, the stator having a guide unit for guiding a fluid flowing through the electric drive motor, the guide unit comprising a tube element and a central body arranged coaxially to the tube element, as well as a plurality of support struts. During operation, fluid flows between the tube element and the central body, past the support struts, in the direction of the compressor. The support struts have a profile, wherein a chord line of the profile and the axis of the stator enclose an angle of attack. Disclosure of the invention

[0006] A compressor is proposed, comprising a housing, a shaft rotatably mounted in the housing on which at least one compressor wheel is fixedly arranged, and an electric drive motor, in particular for an exhaust gas turbocharger of an internal combustion engine. The electric drive motor comprises a rotor comprising at least one permanent magnet and a stator. The stator has an annular yoke and at least one multiphase drive winding for generating a drive magnetic field, as well as a plurality of stator teeth arranged radially with respect to an axis of the stator. The multiphase drive winding has coils arranged radially on each of the stator teeth.The stator further comprises a guide unit for directing a fluid flowing through the electric drive machine. The guide unit includes a tubular element, a central body arranged coaxially to the tubular element, and a plurality of retaining struts. The retaining struts extend radially outwards from the central body with respect to the axis of the stator and connect the central body to the tubular element. The central body has an opening that accommodates the rotor. The flowing fluid flows between the tubular element and the central body, past the retaining struts, towards the compressor. The retaining struts have a profile, wherein a chord line of the profile of the retaining struts and the axis of the stator form an angle of attack α, where 0° < α ≤ 40°.According to the invention, the annular stator yoke and the coils are arranged outside the tube element on the stator teeth, and the angle of attack α changes in a radial direction from the axis of the stator outwards.

[0007] This largely avoids the disadvantages of known electric drive motors and increases the efficiency of the compressor in order to improve the efficiency of the turbocharger and the overall system efficiency.

[0008] Within the scope of the present invention, an "electric drive machine" is understood to be any device configured to generate movement, for example, rotational movement, of another object, in particular by applying an electric current. In particular, the electric drive machine can be configured wholly or partially as an electric motor. Specifically, the electric drive machine can be configured to convert electrical energy into kinetic energy. For this purpose, the electric drive machine comprises at least one rotor and at least one stator. The electric drive machine is used to drive a compressor, in particular for an exhaust gas turbocharger of an internal combustion engine.

[0009] In the context of the present invention, a "compressor" is understood to be any device configured to supply mechanical work to a fluid, for example, a gas. The compressor can, in particular, be configured to increase the pressure and density of the fluid. The compressor can therefore also be referred to as a compressor. In particular, the compressor can be a radial compressor. The radial compressor can be used to add energy to a flowing fluid by means of a rotating impeller, for example, a compressor wheel, according to the laws of fluid mechanics. The radial compressor can be designed such that the fluid flows substantially axially into an impeller, for example, the compressor wheel, and is then deflected radially, i.e., outwards. In particular, the fluid can be compressed, for example, by the outwardly deflected flow direction.

[0010] In the context of the present invention, a "rotor" is understood to be a rotating component of an electric drive machine, such as an electric motor, which is alternatively also referred to as a rotor. The rotor advantageously comprises at least one permanent magnet which interacts with a rotating magnetic field of the stator. In particular, the rotor is, for example, non-rotatably connected to the compressor wheel.

[0011] In the context of the present invention, a "stator" is understood to be a stationary component of an electric drive machine, such as an electric motor, which serves as a common core for induction coils. The stator has an annular yoke, with the stator teeth projecting radially inwards from the yoke and arranged at uniform intervals along the circumference. The stator teeth are wound with a multiphase drive winding. The multiphase drive winding of the stator consists of several coils, with one coil arranged radially on each stator tooth. For example, the coils on the stator teeth can each be mounted by means of a coil holder.In particular, by energizing the phases of the drive winding using a power electronics system designed for this purpose, a rotating drive magnetic field can be generated, which can drive the rotor with a predeterminable torque.

[0012] As described above, the stator further comprises the guide unit for directing a fluid flowing through the electric drive motor, for example, air, in particular ambient air, such as intake air from an internal combustion engine. The stator's guide unit can be configured, in particular, to guide and / or direct the fluid flowing through the electric drive motor. Specifically, the guide unit can, for example, direct the fluid in such a way as to improve the flow towards the compressor wheel, which is preferably arranged downstream. For this purpose in particular, the guide unit's support struts can, for example, have the profile described.

[0013] Within the scope of the present invention, a "profile" of the support strut is understood to be a contour, for example, an outline, in a plane orthogonal to a principal direction of extension of the support strut. In particular, the profile can be the contour of a cross-section of the support strut, for example, the shape of a circumferential line of the support strut. For example, the profile of the support struts can be designed to influence a flow property of the fluid, for example, a flow direction and / or a flow velocity. In particular, the support struts can have an airfoil profile. For example, the airfoil profile of the support struts can be individually adapted and / or optimized to the desired flow property. In particular, the airfoil profile of the support struts can, for example, correspond to a NACA airfoil or an Eppler airfoil.

[0014] For example, the retaining struts can be arranged at uniform intervals around the circumference. In particular, the retaining struts can be evenly distributed around the circumference of the guide unit.

[0015] In the context of the present invention, a "profile chord" is generally understood to be a straight line, for example, an imaginary connecting line, which links two points of the profile that are greatest apart. In particular, the profile chord can be a reference line for defining angles, for example, the angle of attack α, of the profile.

[0016] In particular, the following can apply to the angle of attack α: 0° < α ≤ 30°, for example 1° ≤ α ≤ 28°, for example 2° ≤ α ≤ 26°, for example 3° ≤ α ≤ 24° and / or for example also 4° ≤ α ≤ 22°. Preferably, the following can apply to the angle of attack α: 5° ≤ α ≤ 20°, for example 7° ≤ α ≤ 18°, in particular 8° ≤ α ≤ 17°. Particularly preferably, the following can apply to the angle of attack α: 9° ≤ α ≤ 16°, for example 10° ≤ α ≤ 15°. In particular, positive values ​​of the angle of attack α can be understood as corresponding to a positive direction of rotation of the compressor, for example, a positive direction of rotation of the compressor wheel, especially in the direction of a pre-swirl. For example, with a clockwise direction of rotation of the compressor wheel, the chord line of the airfoil can also be arranged clockwise relative to the axis of the stator at an angle of attack α.

[0017] The angle of attack α changes in the radial direction. In particular, the angle of attack α can vary radially outward from the stator axis, for example, becoming larger or smaller. For instance, a first angle of attack α1 of a first support strut in the immediate vicinity of the central body can differ from a second angle of attack α2 of the first support strut in the immediate vicinity of the tube element. In particular, α1 ≠ α2.

[0018] The profile, in particular the airfoil profile, of the support struts can have at least one leading edge, for example a leading edge or leading edge, and a trailing edge. In particular, the leading edge and the trailing edge can be connected by the chord line. Furthermore, the fluid flow can, for example, run from the leading edge towards the trailing edge. In particular, the fluid can flow along the profile from the leading edge towards the trailing edge. For example, the angle of attack α of the profile, in particular a positive angle of attack α, can direct the fluid wholly or partially, for example partially, in the direction of rotation of the compressor wheel, for example, deflecting it. In particular, the profile, for example the airfoil profile, can have a curvature, for example, profile curvature or camber.For example, the curvature, in particular the profile curvature or camber, can be designed in such a way as to influence the flow direction of the fluid, for example in the direction of rotation of the compressor wheel. For example, the curvature of the profile can guide, in particular direct, the fluid in the direction of rotation of the compressor, for example in the positive direction of rotation of the compressor wheel.

[0019] The profile of the support struts can, for example, be constant in the radial direction. In particular, the profile of the support struts can be constant along the main direction of extension of the support struts, especially in the radial direction with respect to the axis of the stator.

[0020] For example, the retaining struts can have a metallic core. In particular, the metallic core can be made of a magnetizable material, such as iron. For example, the retaining struts can have a metallic core surrounded by a shaping plastic layer. For example, the profile can be shaped by the plastic layer. In particular, the metallic core of the retaining struts can be designed to amplify a drive magnetic field.

[0021] Furthermore, a first side of the central body can be arranged opposite to the flow direction of the fluid, for example, facing the flow of the fluid. In particular, the side of the central body arranged opposite to the flow direction of the fluid can be designed in a flow-optimized shape, for example, in the form of a half-ovoid. Additionally, a second side of the central body opposite the first side, in particular a side facing away from the flow, for example, a side of the central body arranged in the flow direction, can have an opening, for example, a cylindrically shaped opening. In particular, the opening of the central body can, for example, be configured to accommodate the rotor, preferably the rotor with a permanent magnet.

[0022] The pipe element can have at least two sections. In particular, a first section can have a constant diameter. For example, a second section can have a changing diameter. The supporting struts can be connected to the first section of the pipe element. Whereas, for example, the second section of the pipe element can narrow in the opposite direction to the fluid flow.

[0023] In particular, the support struts and the central body can be manufactured as a single piece. For example, the support struts and the central body can be made of the same material, such as plastic. Alternatively, the support struts and the pipe element can also be manufactured as a single piece. In particular, the support struts and the pipe element can be made of the same material, such as plastic.

[0024] In particular, the central body, the support struts, and the pipe element can be manufactured as a single piece, for example, in one piece. For example, the central body, the support struts, and the pipe element, especially the guide element, can be made of one material, for example, plastic.

[0025] Furthermore, the stator can be designed such that, for example, at least one first stator tooth is aligned with at least one first support strut. In particular, the at least one first stator tooth and the at least one first support strut can be integrally connected, for example, as a single piece.

[0026] The central body and / or the tube element can, for example, have axial receiving recesses for receiving one stator tooth each. Advantages of the invention

[0027] The proposed compressor with the electric drive motor offers numerous advantages compared to devices known from the prior art. In particular, for example, the efficiency loss of a conventional compressor can be minimized and / or compensated for. Specifically, the efficiency loss resulting from stator integration into an intake side of the compressor can be compensated for. For example, geometric features of the devices according to the invention, especially of the stator, can be optimized such that the efficiency loss is as small as possible, particularly smaller than in conventional devices. For example, an efficiency loss caused by an unfavorable flow pattern to the compressor wheel, especially a flow error, can be minimized or even compensated for by the proposed devices.For example, the approach error can be halved by the proposed devices compared to conventional devices. For example, the devices according to the invention can have a maximum approach error of 3°, in contrast to an approach error of, for example, 6° in devices known from the prior art.

[0028] Furthermore, the electrically driven compressor according to the invention can deliver greater power, for example, better performance, compared to devices known from the prior art. In particular, an increase in power can be achieved, for example, by increasing the cross-section of a metallic core, especially an iron cross-section, of the supporting struts. For example, the iron cross-section of the devices according to the invention can be larger than the iron cross-section of known devices. Brief description of the drawings

[0029] Further optional details and features of the invention will become apparent from the following description of preferred embodiments, which are shown schematically in the figures.

[0030] They show Figure 1: A sectional view of an embodiment of a compressor with an electric drive motor; Figure 2A: A perspective view of a section of an embodiment of an electric drive motor; Figure 2B: A sectional view of an embodiment of an electric drive motor in the stator area; Figures 3A and 3B: Perspective views of a stator according to a first embodiment ( Figure 3A ) and according to a second embodiment ( Figure 3B Figure 4 shows a sectional view of an embodiment of an electric drive machine in the area of ​​the rotor; and Figure 5 shows a graph of an exemplary efficiency increase of an embodiment of an electric drive machine. Embodiments of the invention

[0031] Figure 1Figure 1 shows an embodiment of a compressor 110, in particular an exhaust gas turbocharger of an internal combustion engine, with an electric drive motor 112 in a sectional view. The compressor 110 comprises a housing 114 and a shaft 116 rotatably mounted in the housing 114. A compressor wheel 118, for example a turbine wheel, is fixedly mounted on the shaft 116. Furthermore, a rotor 120 of the drive motor 112 is also fixedly connected to the shaft 116 and has at least one permanent magnet 122. The drive motor 112 also comprises a stator 124 with at least one multiphase drive winding 126 for generating a drive magnetic field and a plurality of stator teeth 130 arranged radially with respect to an axis 128 of the stator 124.The stator 124 further comprises a guide unit 132 for guiding a fluid flowing through the electric drive machine 112, wherein the guide unit 132 includes a tube element 134, for example a tube element 134 connected to the stator teeth 130, and a central body 136 arranged coaxially to the tube element 134, as well as a plurality of retaining struts 138. The flow direction of the fluid flowing through the electric drive machine 112 is defined as follows: Figure 1 for example, represented by arrows.

[0032] Figure 2A Figure 1 shows a perspective view of a section of an embodiment of an electric drive motor 112, in particular illustrating the central body 136 and six retaining struts 138. For example, the retaining struts 138 and the central body 136 can be made in one piece, in particular in one piece, for example from plastic. The retaining struts 138 extend, as shown in Figure 2AIllustrated, from the central body 136 in the radial direction with respect to the axis 128. In particular, the retaining struts can be arranged at uniform intervals from each other in the circumferential direction. Furthermore, the retaining struts 138 each have a profile 140, for example, an airfoil profile. An exemplary embodiment of the profile 140 is shown in Figure 2B illustrated. In particular, the one in Figure 2B The profile 140 shown is defined by a contour of a cross-section of one of the in Figure 2A illustrated retaining struts 138 deal with, for example, a section along a Figure 2AThe illustrated plane 142 is orthogonal to a principal direction of extension of a first support strut 139. In particular, the support struts 138 can, for example, be arranged at uniform intervals from one another in the circumferential direction. Furthermore, the support struts 138 can, for example, have a metallic core (not shown here). For example, the support struts 138 can have a metallic, for example, a magnetizable, core that is surrounded by a shaping plastic layer. For example, the profile 140 can be formed by the plastic layer. In particular, the metallic core of the support struts 138 can be configured to amplify the drive magnetic field generated by the multiphase drive winding 126.

[0033] Furthermore, the retaining struts 138 are arranged, for example, at an angle to the axis 128 of the stator 124. As, for example, in Figure 2BAs illustrated, a chord line 144 of the profile 140 of the first support strut 139 forms an angle of attack α with the axis 128 of the stator 124, where 0° < α ≤ 40°. For example, the angle of attack α can be 9°. In particular, the angle of attack α can also be variable (not shown here). Furthermore, the profile 140, in particular the airfoil profile, of the support struts 138 can, for example, have a leading edge 146, in particular a leading edge, and a trailing edge 148. In particular, the profile 140 of the support struts 138 can be configured to influence a flow property, for example a flow direction and / or a flow velocity, of the fluid.

[0034] In particular, the profile 140 of the support struts can be numerically optimized, for example, by means of computational fluid dynamics (CFD) analysis. For example, CFD analysis can be used to identify the flow direction of the fluid, especially of incoming air. In particular, the flow direction of the fluid can run from the leading edge 146 towards the trailing edge 148, as indicated, for example, by the arrows in Figure 2B depicted.

[0035] In particular, the flow direction of the fluid can be determined by the Figure 2BProfile 140 of the support struts 138, set at an angle of attack α = 9°, can be influenced such that the fluid flow direction deviates, for example, by a maximum of 3° from the optimal inflow angle of the fluid into a downstream compressor wheel, as illustrated in Table 1. In contrast, as also illustrated in Table 1, a profile 140 aligned parallel to the axis 128 can, for example, influence the fluid flow direction such that the fluid inflow angle into the compressor wheel deviates by 6° from the optimal inflow angle. Table 1: Inflow angle as a function of the angle of attack a Inflow angle [°] optimal -57.19 α = 0° -62.91 α = 9° -59.87

[0036] The 140 airfoil profile can exhibit different properties depending on its design. In particular, airfoil profiles can have different characteristics, such as drag, lift, and area. Drag, for example, can be equivalent to a pressure drop. Lift, for example, can be equivalent to spin. The area can, for example, limit the cross-sectional area of ​​the iron, especially a maximum cross-sectional area. The iron cross-section can be particularly relevant to the performance, for example, of the electric motor.

[0037] For example, when defining or determining, especially when selecting, the profile 140, such as the airfoil or guide vane profile, a conflict of objectives may need to be resolved between minimizing pressure loss and achieving the best possible correction of the impeller's angle of attack. This conflict of objectives can be addressed, for example, by the Figure 2B The illustrated profile 140, for example, can be achieved with a blade profile that may, for instance, feature a laminar depression. A laminar depression is typically defined as a region of the angle of attack α within which the drag is approximately constant and the lift increases. For example, by selecting the angle of attack α at the edge of the laminar depression, a pressure loss can be minimized.

[0038] Furthermore, a profile of airfoil 140 can be identified, for example, by evaluating pressure drop and twist, while simultaneously analyzing the area. Desired properties might include the largest possible area, the lowest possible pressure drop (e.g., drag), and the highest possible twist (e.g., lift). In particular, an airfoil identified in this way could be a NACA airfoil, such as the NACA 64(4)-421, which can be found, for example, on the website http: / / airfoiltools.com. Other airfoils 140, especially airfoils such as Eppler airfoils or airfoils individually adapted to a desired flow characteristic, are also possible.

[0039] In the Figures 3A and 3BVarious embodiments of a stator 124 are shown in perspective views. As shown in the figures, the stator 124 can, in particular, comprise six stator teeth 130, an annular stator yoke 150, and a guide unit 132 for guiding the fluid flowing through the electric drive motor 112. The guide unit 132 can, in particular, comprise a tube element 134, a central body 136, and, for example, six retaining struts 138. As shown in Figure 3B As illustrated, the pipe element 134, for example, has a first region 152 with a constant diameter and a second region 154 with a diameter that narrows in the opposite direction of flow. Furthermore, for example, a first side 156 of the central body 136 facing the direction of flow can be designed in a flow-optimized shape, for example in the form of a half ovoid.

[0040] As in Figure 3BAs illustrated, the multiphase drive winding 126 of the stator 124 can consist of several windings, for example coils 158. In particular, a coil 158 can be arranged radially on each of the stator teeth 130 to form the multiphase drive winding 126. Specifically, the coils 158 can be mounted on the stator teeth 130 by means of a coil holder 160.

[0041] In Figure 4 Figure 1 shows a sectional view of an embodiment of a drive machine in the rotor region. For example, a second side 162 of the central body 136 can have an opening, for example a cylindrically shaped opening. In particular, as shown in Figure 162, the rotor can be a sectional view of an embodiment of a drive machine in the rotor region. For example, a second side 162 of the central body 136 can have an opening, for example a cylindrically shaped opening. In particular, as shown in Figure 162, a second side 162 of the central body 136 can have an opening. In particular .... In the central body 136, a second side 162 of the central body 13 Figure 4As illustrated, the opening on the second side 162 of the central body 136 is designed to accommodate the rotor 120, for example, the rotor 120 with permanent magnet 122. The rotor 120 can, in particular, be rotatably mounted in the central body 136 so that it can rotate about the axis 128, especially the axis 128 of the stator 124. The rotor 120 can be fixedly connected to the shaft 116. For example, the rotor 120 and the shaft 116 can be made in one piece or as a single unit.

[0042] Figure 5Figure 1 shows a graph illustrating an exemplary efficiency increase of an embodiment of a drive machine. In particular, the efficiency of a compressor 110 according to the invention, combined with an electric drive machine 112 according to the invention, is shown using a first data series 164 as a function of a mass flow rate. Furthermore, the efficiency of a conventional compressor, for example, a compressor known from the prior art, is shown using a second data series 166 as a function of a mass flow rate. For example, the efficiency can be given in [%] and the mass flow rate in [kg / s]. In the graph shown here, the efficiency is plotted on the y-axis and the mass flow rate on the x-axis. In particular, as shown in Figure 166, the efficiency can be plotted on the y-axis and the mass flow rate on the x-axis. Figure 5Illustrated, a compressor 110 according to the invention with an electric drive machine 112 according to the invention can achieve an improvement in efficiency of up to 3% compared to compressors known from the prior art, depending on the mass flow rate.

Claims

1. Compressor (110), comprising a housing (114), a shaft (116), which is rotatably mounted in the housing (114) and on which at least one compressor wheel (118) is arranged for conjoint rotation, and an electric drive machine (112), in particular for an exhaust gas turbocharger of an internal combustion engine, wherein the electric drive machine (112) comprises a rotor (120), comprising at least one permanent magnet (122), and a stator (124), wherein the stator (124) has a circular stator yoke (150) and at least one multiphase drive winding (126) for generating a drive magnetic field and also a plurality of stator teeth (130) arranged radially with respect to an axis (128) of the stator (124), wherein the multiphase drive winding (126) has coils (158) which are radially arranged on each of the stator teeth (130), wherein the stator (124) further comprises a guiding unit (132) for guiding a fluid flowing through the electric drive machine (112), wherein the guiding unit (132) comprises a pipe element (134) and a central body (136) arranged coaxially to the pipe element (134) and also a plurality of retaining struts (138), wherein the retaining struts (138) extend radially outwards from the central body (136) with respect to the axis (128) of the stator (124) and connect the central body (136) to the pipe element (134), wherein the central body (136) has an opening which receives the rotor (120), wherein the fluid flowing between the pipe element (134) and the central body (136) passes the retaining struts (138) in the direction of the compressor (110), wherein the retaining struts (138) have a profile (140), wherein a profile chord (144) of the profile (140) of the retaining struts (138) and the axis (128) of the stator (124) include an angle of attack α, where 0° α ≤ 40°, wherein the angle of attack α changes in the radial direction from the axis (128) of the stator (124) to the outside, characterized in that the circular stator yoke (150) and the coils (158) are arranged outside the pipe element (134) on the stator teeth (130).

2. Compressor (110) according to the preceding claim, wherein the retaining struts (138) have an aerofoil profile.

3. Compressor (110) according to either of the preceding claims, wherein for the angle of attack α: 0° < α ≤ 30°.

4. Compressor (110) according to any of the preceding claims, wherein the retaining struts (138) have a metal core, wherein the metal core is surrounded by a plastics material.

5. Compressor (110) according to any of the preceding claims, wherein the profile (140) of the retaining struts (138) has at least a profile leading edge (146) and a profile trailing edge (148), wherein a flow direction of the fluid runs from the profile leading edge (146) in the direction of the profile trailing edge (148).

6. Compressor (110) according to the preceding claim, wherein a first side (156) of the central body (136) is arranged against the flow direction of the fluid and is designed in a flow-optimized form, for example in the form of a half ovoid, wherein a second side (162) of the central body (136), the second side being situated opposite the first side (156), has an opening, for example a cylindrical opening.

7. Compressor (110) according to any of the preceding claims, wherein the pipe element (134) has at least two regions (152, 154), wherein a first region (152) has a constant diameter, wherein a second region (154) has a changing diameter.

8. Compressor (110) according to any of the preceding claims, wherein the retaining struts (138) and the central body (136) are made in one piece.

9. Compressor (110) according to any of the preceding claims, wherein the retaining struts (138) and the pipe element (134) are made in one piece.

10. Compressor (110) according to any of the preceding claims, wherein the central body (136), the retaining struts (138) and the pipe element (134) are made in one piece.

11. Compressor (110) according to any of the preceding claims, wherein at least one first stator tooth is arranged in alignment with at least one first retaining strut (139).

12. Compressor (110) according to the preceding claim, wherein the at least one first stator tooth and the at least one first retaining strut (139) are connected to each other in one piece.

13. Compressor (110) according to any of the preceding claims, wherein the central body (136) and / or the pipe element (134) have axial receiving recesses for receiving one stator tooth (130) each.

14. Compressor (110) according to any of the preceding claims, wherein the rotor (120) is connected to the shaft (116) for conjoint rotation.