FAN WHEEL FOR A ROTOR AND ELECTRIC MACHINE

Description

[0001] The invention relates to a fan wheel for a rotor of an electric machine, wherein the fan wheel is configured and / or designed such that a cooling medium can flow through the rotor in the opposite direction, and the winding heads of a stator surrounding the rotor can be effectively cooled. The invention further relates to an electric machine for a motor vehicle with a rotor and the fan wheel according to the invention.

[0002] Electric machines for motor vehicles are generally known. Such known electric machines typically have a rotor with a fan wheel arranged at each end face. It is also known that the rotor can be permeated with a cooling medium flowing in the opposite direction. Such a technical teaching is known, for example, from EP 2 002 526 B1.

[0003] The aim is to increase the cooling effect of the electric machine, especially the winding heads of the stator that surrounds the rotor circumferentially. In this way, the efficiency of the electric machine can be increased.

[0004] DE 11 2016 002 636 T5 shows a fan wheel according to the preamble of claim 1.

[0005] DE 42 42 132 A1 and DE 10 2004 047 735 A1 each describe a closed electrical machine.

[0006] The object of the invention is to provide a fan wheel for an electric machine with which the cooling effect of the electric machine, in particular the cooling effect on the winding head of the stator surrounding the rotor in the circumferential direction, can be increased.

[0007] This problem is solved by the subject matter of the independent patent claim. Preferred embodiments of the inventions are derived from the dependent claims, the description, and the figures, each feature being able to represent an aspect of the invention both individually and in combination.

[0008] According to the invention, a fan wheel for an electric motor vehicle is provided, comprising an annular base body having at least one intake opening and an air deflection area formed in the circumferential direction of the base body next to the intake opening, wherein the annular base body has a first side and a second side spaced apart in the axial direction of the base body, a plurality of first fan blades arranged spaced apart from each other in the circumferential direction of the base body are arranged on the first side, a plurality of second fan blades arranged spaced apart from each other in the circumferential direction of the base body are arranged on the second side, wherein a second inner section, a second outer section and a second middle section arranged between the second inner section and the second outer section are formed on the second side.the respective section is formed circumferentially, the second fan blades are arranged in the second outer section, and the intake opening is formed in the second inner section.

[0009] In other words, one aspect of the invention is that a fan wheel for the rotor of an electric machine is provided, which has an annular base body. The base body has a first side and a second side spaced axially apart from the base body. Furthermore, at least one intake opening is formed in the base body, extending between the first side and the second side, so that a volume flow of a cooling medium can be guided through the intake opening. Typically, the base body has a plurality of intake openings; preferably, the number of intake openings is even.

[0010] Adjacent to the intake opening or its surrounding edge, an air deflection zone is formed on the first side of the base body. This air deflection zone thus borders the intake opening or its surrounding edge in the circumferential direction of the base body. The air deflection zone is designed and / or configured to change the direction of a volume flow. Preferably, the air deflection zone has a ramp-shaped and / or arc-shaped configuration, so that a volume flow from an axial direction, relative to the longitudinal direction of the base body, can be deflected in the radial direction of the base body. In this way, the volume flow and / or airflow can preferably be directed specifically towards the winding heads of a stator for cooling purposes.

[0011] The fan wheel has its first set of blades on the first side of the base body. The base body also has a second set of blades on its second side. These blades, arranged on both sides of the fan wheel, concentrate and effectively utilize the airflow projected against the winding heads of a stator to increase cooling efficiency.

[0012] According to the invention, a second inner section, a second outer section, and a second middle section arranged between the second inner section and the second outer section are formed on the second side, wherein each section is circumferential, the second fan blades are arranged in the second outer section, and the intake opening is formed in the second inner section. Thus, the second fan blades are arranged in the outer region with respect to the radial direction of the base body in order to direct a volume flow and / or airflow specifically onto a winding head of a stator.

[0013] An advantageous embodiment of the invention is that the base body has, on its first side, a first inner section, a first outer section, and a first middle section arranged between the first inner section and the first outer section, each section extending circumferentially, the first fan blades being arranged in the first outer section, and the intake opening and the air deflection area being formed in the first inner section. In other words, the base body has three sections on its first side with respect to its radial direction: a first inner section with the intake opening and the air deflection area, a first outer section with the first fan blades, and a first middle section in which neither the intake opening nor the fan blades are arranged.Accordingly, the first fan blades are arranged in the outer area with respect to the radial direction of the base body in order to be able to direct a volume flow and / or airflow specifically onto a winding head of a stator.

[0014] In In this context, an advantageous embodiment of the invention provides that the second central section is designed to be recessed in the axial direction of the base body relative to the second outer section. In other words, the second outer section projects forward in the axial direction of the base body relative to the central section. The second fan blades are arranged on this projecting section.

[0015] The transition between the second middle section and the second outer section can be stepped or ramped. A ramped transition can offer aerodynamic advantages for directing a volume flow and / or airflow radially outward from the base body over the second middle section and the second outer section.

[0016] In principle, it is conceivable that the first and second fan blades are identical. A preferred embodiment of the invention is characterized in that the first and / or second fan blades are designed differently from one another. Preferably, the first fan blades can be designed and / or arranged such that they can selectively draw in a volume flow and / or a portion thereof, while the second fan blades accelerate and / or deflect a volume flow and / or a portion thereof in the radial direction of the base body.

[0017] According to a preferred embodiment of the invention, the first fan blades have a curved and / or arcuate profile. Each first fan blade thus has a starting point and an end point, wherein the starting point and the end point are spaced apart from each other in the radial and circumferential directions, and the profile between the starting point and the end point is curved and / or arcuate. Such a design of the fan blades is particularly suitable for drawing in an airflow and / or volume flow.

[0018] An advantageous embodiment of the invention lies in the fact that the second fan blades have a straight design in the radial direction of the base body. In this way, they can selectively blow out and / or direct an airflow and / or volume flow in the radial direction of the base body.

[0019] It is conceivable that the fan wheel is made up of multiple parts. It could therefore comprise several segments that are assembled to form a ring-shaped fan wheel.

[0020] A preferred embodiment of the invention is characterized by the impeller being formed in one piece. Accordingly, the first and second impeller blades are inseparably connected to the annular base body. It is conceivable that the impeller is made of a single material or a composite material. Preferably, the impeller is made of a metal and / or a plastic. It is also conceivable that the impeller could be made of a fiber-reinforced plastic.

[0021] In an advantageous embodiment of the invention, the fan wheel has a plurality of intake openings arranged at circumferential intervals, with the air deflection zone formed between each intake opening. The number of intake openings is preferably an even number. For example, the number X of intake openings is X = 2, 4, 6, or 8. It is conceivable that the number X is also greater than 8.

[0022] The invention further relates to an electric machine for a motor vehicle, with a rotor rotatable about a rotor axis, which has a laminated core with a first end face and a second end face spaced apart in the axial direction of the rotor, a first cooling channel and a second cooling channel different from the first cooling channel, wherein the first cooling channel and the second cooling channel extend within the laminated core between the first end face and the second end face, with two fan wheels according to the invention, which are arranged and / or designed such that the rotor can be permeated with a cooling medium in the opposite direction.

[0023] In other words, the electric machine has a rotor. The rotor comprises a first end face and a second end face spaced axially apart from it. Between the first and second end faces extend a first cooling channel and a second cooling channel, distinct from the first. The first and second cooling channels can run parallel to the longitudinal axis of the rotor, connecting the first and second end faces via the shortest path. Alternatively, the first and second cooling channels can spiral through the rotor, connecting the first and second end faces.

[0024] A first fan wheel is arranged adjacent to and / or mounted on the first end face. Likewise, a second fan wheel is arranged adjacent to and / or mounted on the second end face, wherein the first and second fan wheels are positioned offset from each other on their respective end faces of the rotor such that a cooling medium and / or a volume flow can pass through the rotor in opposite directions. The cooling medium is preferably air.

[0025] An advantageous embodiment of the invention lies in the fact that the first side of the fan wheel faces the first end face of the rotor, the intake opening of the first fan wheel is aligned with the first cooling channel, the air deflection area of ​​the first fan wheel is aligned with the second cooling channel, the first side of the second fan wheel faces the second end face of the rotor, the intake opening of the second fan wheel is aligned with the second cooling channel, and the air deflection area of ​​the second fan wheel is aligned with the first cooling channel. Accordingly, the first and second fan wheels are arranged offset from each other such that, during rotation about its longitudinal axis, the rotor can be subjected to a counter-rotating flow of a cooling medium and / or a volumetric flow.

[0026] In a preferred embodiment of the invention, the rotor is circumferentially surrounded by a stator, wherein the rotor is arranged and / or designed to be rotatable relative to the stator about its longitudinal axis, the rotor and stator are surrounded by a housing, in which a cavity on the loose bearing side and a cavity on the fixed bearing side are formed, which are separated from each other by the rotor and stator, the rotor can be permeated by a cooling medium flowing in the opposite direction between the cavity on the loose bearing side and the cavity on the fixed bearing side, and a first volume flow is formed in the cavity on the loose bearing side and a second volume flow is formed in the cavity on the fixed bearing side by a rotation of the rotor about its longitudinal axis. a first part of the second volume flow can be drawn in through the first fan blades of the first fan wheel via the intake opening of the second fan wheel, guided through the second cooling channel, and blown out radially towards the rotor via the air deflection area of ​​the first fan wheel to cool a winding head of the stator surrounding the rotor in the cavity on the loose bearing side; a second part of the second air flow can be deflected radially via the second fan blades of the second fan wheel to cool a winding head of the stator in the cavity on the fixed bearing side; a first part of the first volume flow can be drawn in through the first fan blades of the second fan wheel via the intake opening of the first fan wheel, guided through the first cooling channel, and blown out radially towards the rotor via the air deflection area of ​​the second fan wheel to cool the winding head of the stator in the cavity on the fixed bearing side.A second part of the first volume flow can be deflected radially via the second fan blades of the first fan wheel to cool the winding head of the stator in the cavity on the loose bearing side.

[0027] It is therefore provided that the stator winding head in the cavity on the side of the electric machine is cooled, on the one hand, by the first part of the first volume flow from the cavity on the side of the fixed bearing, which is drawn in over the first fan blades of the first fan wheel, and on the other hand, by the second part of the second volume flow from the cavity on the side of the fixed bearing. In this way, the volume flows can be directed specifically against the winding heads of the stator, which surrounds the rotor circumferentially, in order to cool them effectively.In this way, the performance of the electric machine can be increased.

[0028] A preferred embodiment of the invention comprises a liquid-cooled bearing shield on the floating bearing side and / or a liquid-cooled bearing shield on the fixed bearing side, and the first volume flow can be guided past the floating bearing shield at least partially, and the second volume flow can be guided past the fixed bearing shield at least partially. Thus, the volume flow and / or airflow can be effectively cooled before being redirected to cool the stator winding heads.

[0029] Finally, a preferred embodiment of the invention consists in the fact that an inner surface facing the rotor of the floating bearing end shield and / or the fixed bearing end shield is at least partially conical, so that the respective inner surface tapers towards the rotor. In this way, the first volume flow and / or the second volume flow can be directed specifically towards the fan wheel.

[0030] Further features are described in the dependent claims and the following exemplary embodiments. These exemplary embodiments are not intended to be limiting, but rather illustrative. They are meant to enable a person skilled in the art to carry out the invention. The applicant reserves the right to make one or more of the features disclosed in the exemplary embodiments the subject of patent claims or to include such features in existing patent claims.

[0031] The exemplary implementations are explained in more detail with reference to figures. These show: Fig. 1 a view of a first side of a fan wheel; Fig. 2 a view of a second side of a fan wheel; Fig. 3 a section through an electric machine.

[0032] Fig. 1 Figure 1 shows a fan wheel 10 for a rotor 12 of an electric machine 14. The fan wheel 10 has a ring-shaped base body 16. The base body 16 comprises a first side 18 and a second side 20 spaced axially from the first side 18.

[0033] The first side 18 has a first inner section 22, a first outer section 24, and a first middle section 26 arranged between the first inner section 22 and the first outer section 24. The respective sections 22, 24, and 26 are formed circumferentially.

[0034] In the first inner section 22 of the first side 18, a plurality of intake openings 28 are formed, which are arranged at regular intervals around the circumference of the base body 16. In the present embodiment, four intake openings 28 are provided. However, it is conceivable that the number of intake openings 28 is greater or less than four. In particular, the number of intake openings 28 is an even number. The intake openings 28 extend between the first side 18 and the second side 20 of the base body 16, so that a volume flow of a cooling medium, in particular air, can be guided through the intake openings 28.

[0035] An air deflection zone 30 is arranged and / or formed between each pair of intake openings 28. The air deflection zone 30 is designed and / or configured to change the direction of a volume flow and / or an airflow. In this case, the air deflection zone 30 has a ramp-shaped and / or arc-shaped configuration, so that a volume flow can be deflected from an axial direction, relative to the longitudinal direction of the base body 16, in the radial direction of the base body 16. In this way, the volume flow and / or airflow can preferably be directed specifically towards the winding heads 32 of a stator 34 surrounding the rotor 12 in order to cool them.

[0036] In the first outer section 24 of the first page 18, a plurality of first fan blades 36 are arranged spaced apart from one another in the circumferential direction. The first fan blades 36 have a curved and / or arc-shaped profile. In other words, a fan blade 36 has a starting point 40 and an end point 42, wherein the starting point 40 and the end point 42 are spaced apart from each other in the radial direction of the base body 16 and in the circumferential direction of the base body 16, and the profile between the starting point 40 and the end point 42 is curved and / or arc-shaped. Such a design of the fan blades 36 is particularly suitable for drawing in an airflow and / or a volume flow.

[0037] Fig. 2 Figure 20 shows the second side 20 of the fan wheel 10. The second side 20 has a second inner section 44, a second outer section 46, and a second middle section 48 arranged between the second inner section 44 and the second outer section 46. The respective sections 44, 46, and 48 are formed circumferentially.

[0038] In the second inner section 44, the intake openings 28 are formed, extending between the first side 18 and the second side 20. In the second outer section 46, a plurality of second fan blades 50 are arranged, spaced apart from each other in the circumferential direction of the base body 16. The second fan blades 50 have a straight shape in the radial direction of the base body 16. In this way, they can selectively blow out an airflow and / or volume flow in the radial direction of the base body 16.

[0039] Furthermore, it can be seen that the second middle section 48 and the second inner section 44 are set back in the axial direction of the base body 16 relative to the second outer section 46.

[0040] Fig. 3 Figure 1 shows a schematic longitudinal section through the electric machine 14. The electric machine 14 has a rotor 12, the rotor 12 being mounted to rotate about its longitudinal axis or rotor axis 52. The rotor 12 has a laminated core with a first end face 54 and a second end face 56 spaced axially from the first end face 54.

[0041] Within the sheet metal package, between the first end face 54 and the second end face 56, there run a plurality of first cooling channels 58 and a plurality of second cooling channels 60, whereby in the present section only one first cooling channel 58 and one second cooling channel 60 are visible.

[0042] A first fan wheel 10a is arranged on the first end face 54. A second fan wheel 10b is also arranged on the second end face 56. The first fan wheel 10a and the second fan wheel 10b have a fan wheel 10 configuration as described in the Fig. 1 and 2 The first fan wheel 10a and the second fan wheel 10b are arranged on the rotor 12 in such a way that, when the rotor 12 rotates about its longitudinal axis or rotor axis 52, a cooling medium, in particular a volume flow V and / or air flow, can flow through it in the opposite direction.

[0043] In particular, the first side 18 of the first fan wheel 10a faces the first end face 54 of the rotor 12, with the intake opening 28 of the first fan wheel 10a aligning with the first cooling channel 58 and the air deflection area 30 of the first fan wheel 10a aligning with the second cooling channel 60. The second fan wheel 10b is arranged correspondingly offset on the second side 20. Thus, the first side 18 of the second fan wheel 10b faces the second end face 56 of the rotor 12, with the intake opening 28 of the second fan wheel 10b aligning with the second cooling channel 60, and the air deflection area 30 of the second fan wheel 10b aligning with the first cooling channel 58. Thus, the first fan wheel 10a and the second fan wheel 10b are arranged offset from each other in such a way that the rotor 12 can be rotated in the opposite direction around its longitudinal axis 52 with a cooling medium and / or a volume flow V.

[0044] The rotor 12 is circumferentially surrounded by the stator 34, the rotor 12 being rotatable relative to the stator 34 about the rotor axis 52. The rotor 12 and stator 34 are enclosed by a housing 62. The housing 62 contains a cavity 64 on the loose bearing side and a cavity 66 on the fixed bearing side, separated from each other by the rotor 12 and stator 34. A cooling medium, in particular a volume flow V or an air flow, flows through the rotor 12 in the opposite direction between the cavity 64 on the loose bearing side and the cavity 66 on the fixed bearing side.

[0045] By rotating the rotor 12 about its rotor axis 52, a first volume flow V1 is formed in the cavity 64 on the loose bearing side and a second volume flow V2 in the cavity 66 on the fixed bearing side. A first part V2a of the second volume flow V2 is drawn in through the first fan blades 36 of the first fan 10a via the intake opening 28 of the second fan 10b, guided through the second cooling channel 60, and blown out radially towards the rotor 12 or base body 16 via the air deflection area 30 of the first fan 10a to cool the winding head 32 of the stator 34 surrounding the rotor 12 in the cavity 64 on the loose bearing side. A second part V2b of the second airflow V2 is deflected via the second fan wheel blades 50 of the second fan wheel 10b in the radial direction of the rotor 12 or base body 16 in order to cool the winding head 32 of the stator 34 in the fixed bearing side cavity 66.Correspondingly, a first part V1a of the first volume flow V1 is drawn in through the first fan blades 36 of the second fan 10b via the intake opening 28 of the first fan 10a, guided through the first cooling channel 58, and blown out radially towards the rotor 12 or the base body 16 via the air deflection area 30 of the second fan 10b to cool the winding head 32 of the stator 34 in the fixed-bearing cavity 66. Furthermore, a second part V1b of the first volume flow V1 is deflected radially via the second fan blades 50 of the first fan 10a to cool the winding head 32 of the stator 34 in the floating-bearing cavity 64.

[0046] The fan blades 36, 50 arranged on both sides of the fan wheel 10 enable targeted and efficient cooling of the winding head 32. In this way, the performance of the electric machine 14 can be increased.

[0047] The housing 62 has a liquid-cooled floating-bearing end shield 68 and a liquid-cooled fixed-bearing end shield 70, wherein the first volume flow V1 is guided at least partially past the floating-bearing end shield 68, and the second volume flow V2 is guided at least partially past the fixed-bearing end shield 70. Thus, the volume flows V1 and V2 can be effectively cooled before being redirected again to cool the winding heads 32 of the stator 34.

[0048] An inner surface 72 of the bearing shield 68 facing the rotor 12 and an inner surface 74 of the bearing shield 70 facing the rotor 12 are at least partially conical, so that the respective inner surface 72, 74 tapers towards the rotor 12. In this way, the first volume flow V1 and / or the second volume flow V2 can be directed towards the respective fan wheel 10.

Claims

1. An impeller wheel (10) for an electric machine (14) of a motor vehicle, having a ring-shaped main body (16) having at least one intake opening (28) and an air deflection region (30) formed next to the intake opening (28) in the circumferential direction of the main body (16), wherein the ring-shaped main body (16) has a first side (18) and a second side (20) spaced apart from the first side (18) in the axial direction of the main body (16), a plurality of first impeller wheel blades (36) are arranged spaced apart from one another in the circumferential direction of the main body (16) on the first side (18), and a plurality of second impeller wheel blades (50) are arranged spaced apart from one another in the circumferential direction of the main body (16) on the second side (20), characterised in that a second inner section (44), a second outer section (46) and a second central section (48) arranged between the second inner section (44) and the second outer section (46) are formed on the second side (20), each section (44, 46, 48) is formed so as to extend circumferentially, the second impeller wheel blades (50) are arranged in the second outer section (46), and the intake opening (28) is formed in the second inner section (44).

2. The impeller wheel according to claim 1, characterised in that the main body (16) has, on the first side (18), a first inner section (22), a first outer section (24) and a first central section (26) arranged between the first inner section (22) and the first outer section (24), each section (22, 24, 26) is formed so as to extend circumferentially, the first impeller wheel blades (36) are arranged in the first outer section (24), and the intake opening (28) and the air deflection region (30) are formed in the first inner section (22).

3. The impeller wheel according to any one of the preceding claims, characterised in that the second central section (48) is designed to be recessed in the axial direction of the main body (16) relative to the second outer section (46).

4. The impeller wheel according to any one of the preceding claims, characterised in that the first impeller wheel blades (36) and / or the second impeller wheel blades (50) are designed differently from one another.

5. The impeller wheel according to any one of the preceding claims, characterised in that the first impeller wheel blades (36) have a curved and / or an arc-shaped profile.

6. The impeller wheel according to any one of the preceding claims, characterised in that the second impeller wheel blades (50) have a straight design in the radial direction of the main body (16).

7. The impeller wheel according to any one of the preceding claims, characterised in that the impeller wheel (10) is formed in one piece.

8. The impeller wheel according to any one of the preceding claims, characterised in that the impeller wheel (10) is made of a metal, a plastic and / or a fibre-reinforced plastic.

9. The impeller wheel according to any one of the preceding claims, characterised in that the impeller wheel (10) has a plurality of intake openings (28) arranged spaced apart from one another in the circumferential direction, wherein the air deflection region (30) is formed between the intake openings (28).

10. An electric machine (14) for a motor vehicle, having a rotor (12) rotatable about a rotor axis (52), which rotor has a laminated core with a first end face (54) and a second end face (56) spaced apart in the axial direction of the rotor (12), a first cooling channel (58) and a second cooling channel (60) different from the first cooling channel (58), wherein the first cooling channel (58) and the second cooling channel (60) extend within the laminated core between the first end face (54) and the second end face (56), having two impeller wheels (10) according to any one of the preceding claims, which are arranged and / or designed such that a cooling medium can flow through the rotor (12) in the opposite direction.

11. The electric machine according to claim 10, characterised in that the first side (18) of the first impeller wheel (10a) faces the first end face (54) of the rotor (12), the intake opening (28) of the first impeller wheel (10a) is aligned with the first cooling channel (58), and the air deflection region (30) of the first impeller wheel (10a) is aligned with the second cooling channel (60), the first side (18) of the second impeller wheel (10b) faces the second end face (56) of the rotor (12), the intake opening (28) of the second impeller wheel (10b) is aligned with the second cooling channel (60), and the air deflection region (30) of the second impeller wheel (10b) is aligned with the first cooling channel (58).

12. An electric machine according to claim 10 or 11, characterised in that the rotor (12) is surrounded by a stator (34) in the circumferential direction, wherein the rotor (12) is arranged and / or designed to rotate relative to the stator (34) about its longitudinal axis (52), the rotor (12) and stator (34) are surrounded by a housing (62), a floating-bearing-side cavity (64) and a fixed-bearing-side cavity (66) are formed in the housing (62), which cavities are separated from one another by the rotor (12) and stator (34), a cooling medium flowing between the floating-bearing-side cavity (64) and the fixed-bearing-side cavity (66) can flow through the rotor (12) in opposite directions, a first volume flow (V1) is formed in the floating-bearing-side cavity (64) and a second volume flow (V2) is formed in the fixed-bearing-side cavity (66) by rotating the rotor (12) about its longitudinal axis (52), - a first part (V2a) of the second volume flow (V2) can be drawn in through the first impeller wheel blades (36) of the first impeller wheel (10a) via the intake opening (28) of the second impeller wheel (10b), can be guided through the second cooling channel (60), and can be blown out in the radial direction of the rotor (12) via the air deflection region (30) of the first impeller wheel (10a) in order to cool a winding head (32) of the stator (34) surrounding the rotor (12) in its circumferential direction in the floating-bearing-side cavity (64), - a second part (V2b) of the second air flow (V2) can be deflected in the radial direction of the main body (16) over the second impeller wheel blades (50) of the second impeller wheel (10b) to cool a winding head (32) of the stator (34) in the fixed-bearing-side cavity (66), - a first part (V1a) of the first volume flow (V1) can be drawn in through the first impeller wheel blades (36) of the second impeller wheel (10b) via the intake opening (28) of the first impeller wheel (10a), can be guided through the first cooling channel (58), and can be blown out in the radial direction of the rotor (12) via the air deflection region (30) of the second impeller wheel (10b) in order to cool the winding head (32) of the stator (34) in the fixed-bearing-side cavity (66), - a second part (V1b) of the first volume flow (V1) can be deflected in the radial direction of the main body (16) via the second impeller wheel blades (50) of the first impeller wheel (10a) in order to cool the winding head (32) of the stator (34) in the floating-bearing-side cavity (64).

13. The electric machine according to claim 10 or 12, characterised in that the housing (62) has a liquid-cooled floating-bearing-side bearing shield (68) and / or a liquid-cooled fixed-bearing-side bearing shield (70), and the first volume flow (V1) can be guided past the floating-bearing-side bearing shield (68) at least in sections, and the second volume flow (V2) can be guided past the fixed-bearing-side bearing shield (70) at least in sections.

14. The electric machine according to claim 13, characterised in that an inner side (72, 74) facing the rotor (12) of the floating-bearing-side bearing shield (68) and / or the fixed-bearing-side bearing shield (70) is at least partially conical, such that the respective inner side is tapered towards the rotor (12).