Electric motor, vehicle and method for cooling an electric motor

Abstract

The present invention relates to an electric motor of a vehicle, the electric motor including: a stator; a rotor rotatable relative to the stator about a rotor rotation axis to generate a torque; an end plate located at an axial end of the rotor and coupled to the rotor in a non-rotating manner; and a plurality of cooling fins. The cooling fins are provided on the end plate and are movable relative to the end plate such that at least one of an orientation of the cooling fins relative to a radial perpendicular to the rotor rotation axis and a height at which the cooling fins protrude from the end plate is adjustable.

Description

TECHNICAL FIELD

[0001] The present invention relates to an electric motor, a vehicle comprising the electric motor, and a method of cooling the electric motor. BACKGROUND

[0002] In an electric vehicle, in particular in an electric car, a high-power electric motor is employed to drive the vehicle. Generally, various measures are taken to cool the electric motor.

[0003] For example, in order to improve the cooling of the electric motor, cooling fins can be provided on an end plate of a rotor of the electric motor. When the rotor rotates, the cooling fins generate an air flow along the end plate and the cooling fins, thereby contributing to the removal of heat from the electric motor. Also, the cooling fins act as a heat sink by increasing the surface of the end plate. For example, such a cooling principle is described in US 6 879 078 B2.

[0004] Further, US 5 763 969 A describes an electric motor comprising a cooling fan which can be coupled to a rotating shaft of the electric motor.

[0005] The cooling fins rotating together with the rotor and the cooling fan rotating together with the rotor contribute to the removal of heat from the electric motor. However, since both the cooling fins and the cooling fan are rotated by the rotor of the electric motor, the torque output of the electric motor can be reduced due to the resistance of the cooling fins.

[0006] Therefore, there is a need to find an improved solution for cooling an electric motor.

[0007] The information disclosed in this Background section is only for the purpose of enhancing the understanding of the background of the invention and can include matters known by those skilled in the art. SUMMARY

[0008] (I) Technical problem to be solved

[0009] The present invention relates to an electric motor, a vehicle comprising the electric motor, and a method for cooling the electric motor.

[0010] (II) Technical solution

[0011] According to a first aspect, an electric motor for a vehicle, such as a car, comprises a stator, a rotor rotatable relative to the stator about a rotor rotation axis to generate a torque, an end plate located at an axial end of the rotor and coupled to the rotor in a non-rotating manner, and a plurality of cooling fins provided on the end plate. The cooling fins are movable relative to the end plate such that at least one of an orientation of the cooling fins relative to a radial perpendicular to the rotor rotation axis and a height of the cooling fins protruding from the end plate is adjustable or variable.

[0012] According to a second aspect of the present application, a vehicle, such as a road vehicle, e.g. a car, comprises an electric motor according to the first aspect of the present application.

[0013] According to a third aspect of the present application, a method for cooling an electric motor according to the first aspect of the present application is provided. The method comprises the steps of rotating a rotor of the electric motor, moving a cooling fin between an open position and a closed position to vary an air flow along an end plate of the rotor, wherein in the open position the cooling fin protrudes from the end plate of the rotor or is at least partially oriented in a radial direction perpendicular to a rotation axis of the rotor, and in the closed position the cooling fin is arranged to be flush with the end plate of the rotor or transverse to the radial direction.

[0014] One of the concepts of the present application is to provide an adjustable cooling fin on an end plate that rotates together with a rotor of an electric motor. The cooling fin can be adjusted in that a height by which the cooling fin protrudes from the end plate can be increased or decreased. Additionally or alternatively, the cooling fin can be moved relative to the radial direction, which can be oriented to substantially align with a flow direction perpendicular to the radial direction when the rotor rotates around a rotor rotation axis.

[0015] Since the orientation of the cooling fin relative to the radial direction and / or the height by which the cooling fin protrudes from the end plate can be varied, a reference area of the cooling fin that is effective when the rotor rotates around the rotor rotation axis can be varied to increase or decrease a fluid flow along the cooling fin and / or a turbulence induced by the cooling fin. Thereby, the cooling effect can be adjusted as required depending on various operating conditions of the electric motor. For example, when a higher cooling power is required, then compared to a situation where a lower cooling power is required, the cooling fin can be moved such that the cooling fin protrudes more from the end plate or the cooling fin can be moved such that the cooling fin is closer to the radial direction. Thereby, the cooling power can be effectively adjusted as required.

[0016] Another advantage is that in order to reduce the reference area of the cooling fin, the cooling fin can be retracted or the cooling fin can be moved in an orientation that extends substantially transverse to the radial direction or perpendicular to the radial direction. As a result, the resistance induced by the cooling fin can be reduced when necessary, whereby the output of the electric motor can be increased.

[0017] Further embodiments of the present application are described in the following with reference to the drawings.

[0018] According to some embodiments, the cooling fin can be moved linearly along the rotor rotation axis to vary the height by which the cooling fin protrudes from the end plate. That is, the cooling fin can be moved in a direction transverse to the end plate such that the cooling fin protrudes from the end plate to a certain extent. Thereby, a simple adjustment method is provided.

[0019] According to some embodiments, the cooling fins can be moved between a retracted or closed position in which the cooling fins are arranged flush with the outer side of the end plate and an operational or open position in which the cooling fins protrude from the outer side of the end plate. In the closed position, the height by which the cooling fins protrude from the outer side is 0. In the open position, the height by which the cooling fins protrude is greater than 0, for example the height by which they protrude is a few centimeters, for example between 0.5 cm and 10 cm. In the closed position the cooling fins are arranged flush with the outer side, so that the resistance based on the cooling fins can advantageously be reduced to a minimum.

[0020] According to some embodiments, the cooling fins can be mounted to a carrier structure, for example a carrier plate or frame, and extend into the receiving opening of the end plate, wherein the carrier structure is linearly guided along the rotor rotation axis. The carrier structure is non-rotatable relative to the rotor or rotates together with the rotor. For example, the carrier structure can be guided on a carrier shaft which is arranged coaxially to the rotor rotation axis. In order to move the carrier structure, an actuator such as a spindle drive or the like can be provided. By providing a portion of the cooling fins or all of the cooling fins on a common carrier structure, a synchronous linear movement of the cooling fins can easily be achieved.

[0021] According to some embodiments, the cooling fins can be rotated about a fin rotation axis which extends along the rotor rotation axis. Thus, the cooling fins can be pivoted or rotated such that one end of each cooling fin is positioned closer to or further away from the rotor rotation axis. Thus, the resistance of each cooling fin which is generated when the rotor rotates can be increased or decreased. When the rotor rotates, the flow velocity transverse to the radial direction depends on the radial position and increases with increasing distance from the rotor rotation axis. Thus, by rotating the cooling fins about a fin rotation axis which extends along the rotor rotation axis, the airflow along the end plate can easily be increased even at inner radial positions.

[0022] According to some embodiments, the cooling fins can include a fin longitudinal axis, and the fin longitudinal axis can be rotatable between an aligned or closed position in which the fin longitudinal axis extends transversely to the radial direction and an open position in which the fin longitudinal axis extends along the radial direction. For example, the fin longitudinal axis can be defined by a chord line, which is a straight line connecting the leading edge and the trailing edge of opposite sides of the cooling fin. In the closed position, the cooling fin can be oriented along a tangent of a circle, the center of which is the rotor rotation axis and which includes the fin rotation axis. That is, in the closed position, the cooling fin is oriented such that a first reference area is effective when the rotor rotates about the rotor rotation axis. In the rotated or open position, the cooling fin is oriented such that a second reference area is effective when the rotor rotates about the rotation axis, and the second reference area is larger than the first reference area. The effective reference area can be defined as the projected area of the cooling fin when the cooling fin is viewed in the direction of the tangent of the circle centered on the rotor rotation axis and including the fin rotation axis. Thus, the cooling power and the drag of the cooling fin can be easily varied.

[0023] According to some embodiments, the electric motor can further include an operating mechanism configured to rotate the cooling fins in synchronization. Thus, the cooling power can be more evenly distributed around the end plate.

[0024] According to some embodiments, the operating mechanism can include a center operating shaft, a center gear mounted on the center operating shaft and rotatable by the center operating shaft, and a plurality of fin gears coupled to the center gear, wherein each fin gear is coupled to a pin defining a fin rotation axis of each cooling fin. For example, each cooling fin can be coupled to or fixed to a pin mounted in the end plate, so as to be rotatable about the fin rotation axis. The fin gears including teeth are fixed to the pins, and can be meshed with the center gear. The center gear is mounted on an operating shaft or a driving shaft, which can be driven by, for example, an auxiliary motor. Thus, the center gear is rotated by rotating the center operating shaft, which will cause the rotation of the fin gears and the pins coupled to the fins. Thus, for example, when higher drag acts on the cooling fins, for example, when the rotor rotates at a high rotation speed, a gear ratio that easily adjusts the fin orientation can be set. For example, the center operating shaft can be positioned coaxially with the rotor rotation axis. For example, the output shaft of the rotor can be implemented as a hollow shaft, and the center operating shaft can extend at least partially within the hollow shaft. Thus, a compact mechanism can be provided.

[0025] According to some embodiments, the cooling fins can be plate-shaped. That is, the thickness of the cooling fins can be smaller than the side length of the cooling fins. In this context, the "plate-shaped" can include cooling fins having a planar or flat surface, but can also include cooling fins having a curved surface. For example, the plate-shaped cooling fins can extend in an arc-shaped cross-section.

[0026] According to some embodiments, the vehicle can be a road vehicle comprising at least one wheel and a drive train for rotating the at least one wheel, and the electric motor is mechanically coupled to the drive train to supply torque to the drive train. For example, the vehicle can be a car, a truck, a bus, etc. The vehicle can also be a motorcycle, for example. The drive train can optionally comprise a gear box that couples an output shaft of the electric motor to a driven shaft. However, the electric motor can also be directly connected to the driven shaft. Typically, the electric motor can be a drive motor of the vehicle. The adjustable cooling fins thus contribute to improve the efficiency of the vehicle.

[0027] According to some embodiments, the method can further comprise capturing a temperature of at least one of the rotor and the stator, wherein the step of changing the airflow can comprise a step of controlling at least one of the height of the cooling fins protruding from the end plate and the orientation of the cooling fins relative to the radial based on the captured temperature. Optionally, the control can comprise performing an open loop control or a closed loop control. Controlling the fins based on the temperature of the rotor and / or the stator, the overheating of the electric motor can thus be prevented more reliably.

[0028] According to some other embodiments, the electric motor can be a drive motor of the vehicle, and the method can further comprise a step of capturing an operating state of the vehicle, wherein the step of changing the airflow can comprise a step of controlling at least one of the height of the cooling fins protruding from the end plate and the orientation of the cooling fins relative to the radial based on the captured operating state, the operating state can comprise one or more of a driving speed of the vehicle, an electric power consumption of the electric motor, a state of charge of a battery supplying energy to the electric motor, or a selected driving mode such as a "sport mode", an "efficiency mode", a "normal mode". For example, if the driving speed of the electric motor is high, the convection caused by the driving speed can sufficiently cool the electric motor, and the cooling fins can thus be adjusted to be in a closed or retracted position. Similarly, in an "efficiency mode" or when the state of charge of the battery decreases below a threshold, the cooling fins can be adjusted to be in a closed or retracted position to prevent a decrease in efficiency that can be caused by the resistance due to the cooling fins. On the other hand, when the electric motor temperature increases due to a low speed driving or a high power output in a sport mode of the electric motor, the cooling fins can be adjusted to be in an open position to increase the airflow over the end plate and thus improve the heat dissipation.

[0029] Features and advantages are also disclosed for the method with respect to the electric motor and vice versa. BRIEF DESCRIPTION OF DRAWINGS

[0030] For a more complete understanding of the present application, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings and the following description. The application is described more fully below with reference to the accompanying drawings, in which example embodiments are shown.

[0031] Figure 1is a schematic cross-sectional view of an electric motor according to an embodiment of the present application.

[0032] Figure 2 is a plan view of the outer side of an end plate of an electric motor according to an embodiment of the present application, and shows three different rotational directions (A), (B), (C) of cooling fins.

[0033] Figure 3 is a simplified schematic cross-sectional view of a rotor of an electric motor according to an embodiment of the present application.

[0034] Figure 4 is a plan view of the inner side of an end plate of a rotor. Figure 3

[0035] Figure 5 is a cross-sectional view of an end plate portion of an electric motor according to an embodiment of the present application, and shows three different positions (A), (B), (C) of cooling fins.

[0036] Figure 6 is a simplified schematic cross-sectional view of a rotor of an electric motor according to another embodiment of the present application.

[0037] Figure 7 is a graph of the relationship between rotational speed and cooling power / resistance of an electric motor according to another embodiment of the present application.

[0038] Figure 8 is a functional block diagram of a vehicle according to an embodiment of the present application.

[0039] Figure 9 is a perspective view of a cooling fin of an electric motor according to an embodiment of the present application.

[0040] Figure 10 is a flowchart of a method according to an embodiment of the present application

[0041] Like reference numerals refer to like components throughout the drawings.

[0042] Reference numeral explanation

[0043] 1: Electric motor 2: Stator

[0044] 3: Rotor 4: End plate

[0045] 4A: First end plate 4B: Second end plate

[0046] 4a: Outer side 4b: Inner side

[0047] 5: Cooling fin 5a: First face

[0048] 5b: Second face 6: Carrier structure ​

[0049] 8, 9: operating mechanism 20: inner space

[0050] 30: output shaft 31: first axial end

[0051] 32: second axial end 40: central hole

[0052] 41: accommodation opening 51, 52: edge

[0053] 81: central operating shaft 82: central gear

[0054] 83: fin gear 84: pin

[0055] 90: main shaft driver 100: vehicle

[0056] 101: wheel 102: drive train

[0057] 103: battery 104: controller

[0058] 105: sensor system A3: rotor rotation axis

[0059] A5: fin rotation axis h5: height

[0060] 11: dashed line 12: solid line

[0061] s1: upper / upper limit s2: lower / lower limit

[0062] L5: fin longitudinal axis M: method

[0063] M1-M6: method steps M61-M63: method steps

[0064] R: radial DETAILED DESCRIPTION

[0065] Figure 1 An electric motor 1 is schematically illustrated. The electric motor 1 can comprise a stator 2, a rotor 3, an end plate 4, and cooling fins 5.

[0066] The stator 2 can comprise windings (not shown) for generating a rotating electromagnetic field. As shown, the stator 2 can have a cylindrical shape and can define an inner space 20. Figure 1

[0067] The rotor 3 can comprise electric windings and / or magnets (not shown). As shown, the rotor 3 can have a substantially cylindrical shape. As shown, the rotor 3 can be arranged within the inner space 20 of the stator 2. Figure 1 Figure 1 ​​As shown, the rotor 3 can be located in an inner space 20 of the stator 2. Alternatively, the stator 2 can be located in an inner space of the rotor 3. The rotor 3 is rotatably mounted by, for example, bearings (not shown) so that the rotor 3 can rotate relative to the stator 2 about a rotor rotation axis A3. In particular, the rotor 3 can be rotated by a rotating electromagnetic field generated by the stator 2 and thereby generate a torque. As Figure 1 As shown, the input shaft 30 can be fixed to the rotor 3 to transmit the torque.

[0068] As shown, the input shaft 30 can be fixed to the rotor 3 to transmit the torque. Figure 1 Further shown, a first end plate 4A can be fixed to a first axial end 31 of the rotor 3 and a second end plate 4B can be fixed to a second axial end 32 of the rotor 3, wherein the second axial end 32 is opposite to the first axial end 31 with respect to the rotor rotation axis A3. Although Figure 1 The electric motor 1 is shown including both the first end plate 4A and the second end plate 4B, the electric motor 1 can also include only one of the first end plate 4A and the second end plate 4B. Thus, only one end plate 4 will be described below.

[0069] The end plate 4 is fixed to the rotor 3 in a non-rotational manner by, for example, screws, bolts or similar components. Thus, when the rotor 3 rotates about the rotor rotation axis A3, the end plate 4 rotates together with the rotor 3 when the rotor 3 rotates. As Figure 1 As shown, the end plate 4 can include an outer side 4a facing away from the rotor 3 and an inner side 4b opposite to the outer side 4a and facing the rotor 3. The inner side 4b and the outer side 4a can be planar or flat. Alternatively, local recesses or protrusions can be provided on the outer side 4a and / or the inner side 4b to accommodate, for example, screws or mounting structures. As Figure 2 As shown, the end plate 4 can include a circumference, for example, a circular circumference. Generally, the circumference of the end plate 4 can correspond to a circumference of the rotor 3. Additionally, a central hole 40 can be provided, through which the output shaft 30 can extend.

[0070] The end plate 4 can be made of, for example, an aluminum alloy or a similar metallic material. Alternatively, the end plate 4 can be made of a plastic material or a fiber composite material.

[0071] The cooling fins 5 of the electric motor 1 generate an air flow along the outer side 4a and / or the inner side 4b of the end plate 4, thereby serving to cool the stator 2 and the rotor 3. As Figure 1 As shown, the cooling fins 5 are provided on or located on the end plate 4. Figure 9 The plate-shaped cooling fins 5 are exemplarily shown including a first face 5a and a second face 5b in an opposite direction to the first face 5a. As Figure 9 As shown, the first face 5a can be convex and the second face 5b can be concave. Alternatively, the first face 5a and the second face 5b can also be flat. AsFigure 9 Further shown, the cooling fin 5 can comprise a fin longitudinal axis L5, which can be defined by a connecting line between opposite edges 51, 52 of the cooling fin 5. The cooling fin 5 can be made of a metallic material, a plastic material or a fiber composite material.

[0072] As shown in Figure 1 and Figure 3 , the cooling fin 5 is arranged at the outer side 4a of the end plate 4, or generally protrudes from the outer side 4a of the end plate 4. As shown in Figure 2 , the cooling fin 5 can be rotatable about a fin rotation axis A5. For example, the cooling fin 5 can be directly mounted to the end plate 4 by a pin 84 defining the fin rotation axis A5. Generally, the fin rotation axis A5 extends along or parallel to the rotor rotation axis A3.

[0073] As shown in Figure 2 , the cooling fin 5 can be rotated to change the orientation of the fin longitudinal axis L5 relative to a radial direction R perpendicular to the rotor rotation axis A3. For example, Figure 2 an exemplary state (A) is shown, in which the fin longitudinal axis L5 is oriented transversely or substantially perpendicularly relative to the radial direction R. In this case, the fin longitudinal axis L5 can be parallel to a circle centered on the rotor rotation axis A3 and including the fin rotation axis A5. For example, this orientation of the cooling fin 5 can be referred to as a closed or aligned position. As shown in Figure 2 , a partial view (A) of the closed or aligned position, when the end plate 4 is rotated together with the rotor 3 about the rotor rotation axis A3, the cooling fin 5 is substantially oriented in a streamlined manner, thus without or minimizing drag and air flow along the outer side 4a.

[0074] In Figure 2 , a partial view (C) of a fully open position is shown, in which the cooling fin 5 is oriented such that the fin longitudinal axis L5 extends along the radial direction R. In this state, when the end plate 4 is rotated together with the rotor 3 about the rotor rotation axis A3, the first face 5a or the second face 5b of the cooling fin 5 extends substantially transversely to the flow direction, thereby causing air flow and / or increasing turbulence along the outer side 4a of the end plate 4. Thereby, the cooling of the end plate 4, and thus of the electric motor 1, is promoted. On the other hand, the cooling fin 5 causes drag, which will reduce the torque output on the output shaft 30.

[0075] In Figure 2A partial view (B) shows the orientation of the cooling fins 5 between the closed position and the fully open position. In this case, an air flow is generated along the outer side 4a of the end plate 4, which is less than the air flow in the fully open position. The cooling fins 5 can be moved or rotated such that the cooling fins 5 are in any position between the closed or aligned position and the fully open position. Typically, the orientation of the cooling fins 5 relative to the radial direction R is adjustable.

[0076] Figure 3 and Figure 4 An optional operating mechanism 8 is shown, which is configured to rotate the cooling fins 5 synchronously. The operating mechanism 8 can comprise a central operating shaft 81, a central gear 82 and fin gears 83. As Figure 3 shown, the central operating shaft 81 can be arranged coaxially to the rotor rotation axis A3. The central gear 82, which can be a gear, for example, can be non-rotatably fixed to the central operating shaft 81 by means of shrinkage or other means, for example. Thus, when the central operating shaft 81 is rotated, the central gear 82 is rotated. In order to move the central operating shaft 81, an actuator (not shown) can be provided.

[0077] The fin gears 83 can also be gears, and each fin gear 83 is coupled or fixed to a pin 84. Each pin 84 can extend through a fin opening of the end plate 4, which extends between the inner side 4b and the outer side 4a of the end plate 4. Each cooling fin 5 is coupled to each pin 84. As Figure 4 shown, the fin gears 83 are in mesh with the central gear 82. Thereby, when the central gear 82 is rotated by the central operating shaft 81, the central gear 82 causes a rotation of the fin gears 83, and thereby a rotation of the cooling fins 5 about the fin rotation axis A5. For example, as Figure 3 shown, the central gear 82 and the fin gears 83 can be arranged at the inner side 4b of the end plate 4. As Figure 3 shown, the pins 84 can be directly mounted to the end plate 4. Alternatively, a carrier structure such as a frame or a plate can be provided, which extends parallel to the end plate, wherein the pins 84 can be mounted to the carrier structure.

[0078] As Figure 3 and Figure 4 shown, the gear mechanism can be replaced by other mechanisms. For example, each cooling fin 5 can be moved by a separate actuator. Another possibility to move the cooling fins 5 synchronously can be a belt drive or a lever drive, for example. Typically, an operating mechanism 8 can be provided, which is configured to rotate the cooling fins 5 synchronously.

[0079] Additionally or alternatively to rotating the cooling fins 5 about the fin rotation axis A5, the cooling fins 5 can be linearly moved along or parallel to the rotor rotation axis A3 to change the height h5 of the cooling fins 5 protruding from the end plate 4. Figure 5An enlarged cross-sectional view of the end plate 4 in the region where cooling fins 5 are provided is shown as an example. Figure 5 As shown, the cooling fins 5 can be disposed or guided into a receiving opening 41 in the end plate 4, the receiving opening 41 opening on the outer side 4a of the end plate 4 and optionally extending between the outer side 4a and the inner side 4b of the end plate 4. Typically, the cooling fins 5 can be moved laterally to the outer side 4a of the end plate 4 by, for example, a linear operating mechanism 9.

[0080] Figure 5 Three states (A), (B), and (C) that the cooling fins 5 can take are illustrated exemplarily. Figure 5 In the retracted or closed position shown in partial view (A), the cooling fins 5 can be configured to be flush with the outer surface 4a of the end plate 4. Figure 5 In the partial view (C), the fully open state or position is shown, with the cooling fins 5 protruding a height h5 from the outer side 4a of the end plate 4. Figure 5 Partial view (B) shows the cooling fins 5 positioned between the closed and fully open positions, wherein the height h5 of the cooling fins 5 protruding from the outer side 4a of the end plate 4a is less than the height in the fully open position. Therefore, the cooling fins 5 can typically move relative to the end plate 4, making the height h5 of the cooling fins 5 protruding from the end plate 4 adjustable.

[0081] exist Figure 5 In the closed or retracted position shown in partial view (A), the cooling fins 5 generate no airflow or turbulence at all, or generate minimal airflow or turbulence, on the outer surface 4a of the end plate 4. The more the cooling fins 5 protrude from the outer surface 4a, the greater the airflow and / or turbulence generated on the outer surface 4a of the end plate 4, and the greater the resistance acting on the cooling fins 5, which reduces the torque output of the electric motor 1.

[0082] Figure 6 An exemplary linear operating mechanism 9 is shown, configured to synchronously move the cooling fins 5. For example, the operating mechanism 9 may include a carrier structure 6 and optionally a spindle drive 90 or other actuator. The carrier structure 6 may be implemented as, for example, a plate or frame configured to extend parallel to and rotate with the end plate 4 on the side of the inner side 4b of the end plate 4. The cooling fins 5 may be attached or mounted to the carrier structure 6 by, for example, pins, screws, or similar components. For example, the cooling fins 5 may be integrally formed with the carrier structure 6. Figure 6 As shown, the cooling fins 5 attached to the support frame structure 6 extend into the receiving opening 41 of the end plate 4.

[0083] The carrier structure 6 can be linearly guided along the rotor rotation axis A3 or generally in a direction transverse to the outer side 4a of the end plate 4, so as to move the cooling fins 5 between the retracted position and the open position by moving the carrier structure 6. For example, the carrier structure 6 can be linearly guided on the output shaft 30 of the rotor 3 or on a separate guide shaft (not shown).

[0084] For example, as shown in Figure 6 , a spindle drive 90 can be used to move the end plate 4. The spindle drive 90 can include a drive actuator 91, such as an electric motor, and a spindle 92 coupled to the carrier structure 6. The drive actuator 91 can be configured such that the drive actuator 91 can be fixedly arranged or mounted relative to the end plate 4 and can linearly move the spindle 92 along the rotor rotation axis A3. For example, as shown in Figure 6 , the drive actuator 91 and the spindle 92 can be located within the output shaft 30. In this case or generally, the output shaft 30 can be embodied as a hollow shaft. Figure 6 It is exemplarily shown that a separate spindle drive 90 can be arranged for each end plate 4. However, it is also possible to arrange one common spindle drive 90 for both end plates 4A, 4B. For example, the drive actuator 91 can be configured such that the drive actuator 91 can be coupled to both spindles 92 and can move each spindle 92 individually or in cooperation with the other spindle 92.

[0085] Figure 7 A schematic graph is exemplarily shown in which the rotational speed of the rotor 3 is shown on the abscissa X and the heat transfer rate and the resistance acting on the rotor 3 due to the cooling fins 5 are shown on the ordinate Y. In Figure 7 , the dashed line l1 represents the development of the resistance and the heat transfer for a fixed position of the cooling fins 5. As shown, with increasing rotational speed of the rotor 3, not only the resistance but also the heat transfer rate increases. Figure 7 The solid line l2 in Figure 2 represents the boundary of the operating region that can be achieved by the above-mentioned electric motor 1. Since the cooling fins 5 can be moved between a closed position in which hardly no resistance and heat transfer or only a minimum resistance and heat transfer occurs Figure 5 (A) and Figure 2 (C) of Figure 5 (C), the rotor 3 can be rotated at a very fast speed without resistance or with only a minimum resistance. On the other hand, the heat transfer can be increased at low rotational speeds by moving the cooling fins 5 to the open position. In Figure 7In this context, the upper part sl of the linear increase of the solid line l2 corresponds to the fully open position of the cooling fins 5. The lower part s2 of the solid line l2 coinciding with the horizontal axis X corresponds to the closed position of the cooling fins 5.

[0086] Figure 8 A block diagram of a vehicle 100 which can comprise the electric motor 1 described above is schematically shown. The vehicle 100 can be a road vehicle, such as a car, a bus, a truck or a motorcycle, etc. As Figure 8 is shown, the vehicle 100 can comprise the electric motor 1, at least one wheel 101, a driveline 102, an optional battery 103 and a further optional controller 104.

[0087] The electric motor 1 can be electrically connected to the optional battery 103, which can be a rechargeable battery, for example, supplying electrical energy to the electric motor 1. The electric motor 1 is mechanically coupled to the driveline 102 to supply torque to the driveline 102, and the driveline 102 is configured to supply torque to one or more wheels 101 to rotate the wheels 101 to drive the vehicle 100.

[0088] The controller 104 is connected to the electric motor 1 and can optionally be connected to the battery 103. In addition, a sensor system 105 comprising various sensors can be provided. For example, a sensor for capturing the temperature of the stator 2 and / or the rotor 3 of the electric motor 1, a wheel speed sensor for capturing the wheel speed of the wheels, etc. can be provided. The sensor system 105 can be connected to the controller 104. The controller 104 can be connected to the electric motor 1 and / or the sensor system 105 by a wired connection or a wireless connection to transmit signals. The controller 104, which can be an electronic control device, can be configured to generate control commands for operating one or more actuators that move the cooling fins 5 relative to the end plate 4. For example, the control commands generated by the controller 104 can move the operating mechanism 8, 9 to move the cooling fins 5 or rotate the cooling fins 5. The controller 104 can comprise a processing unit (not shown), for example, a CPU, an ASIC, an FPGA, etc., and a data memory (not shown), for example, a flash drive, a hard drive, a CD-ROM, a DVD-ROM, etc., which can be read by the processing unit.

[0089] Figure 10 A flowchart of a method M for cooling the electric motor 1 is exemplarily shown. The method M can be performed with the electric motor 1 described above, in particular the electric motor 1 assembled in the vehicle 100. For example, the controller 104 can execute software that causes the controller 104 to perform the steps of the method M.

[0090] In step M1, the rotor 3 is rotated due to a rotating electromagnetic field generated by, for example, the stator 2.

[0091] In optional step M2, the temperature of the stator 2 and / or rotor 3 can be captured by means of, for example, the sensor system 105 of the vehicle 100. The captured temperature of the stator 2 and / or rotor 3 can be transmitted to the controller 104.

[0092] In an optional step M3, which may be performed additionally after or in lieu of step M2, the operating state of vehicle 100 may be captured or determined. The operating state may include the vehicle's speed, the power consumption of the electric motor, the state of charge of the battery supplying energy to the electric motor, or one or more selected driving modes such as "Sport Mode," "Efficiency Mode," or "Normal Mode." For example, the speed may be determined by controller 104 based on wheel speeds captured by wheel speed sensors of sensor system 105. Similarly, the state of charge of the battery may be determined by controller 104. For example, the selected driving mode may be transmitted from a user interface (not shown) to controller 104. In each driving mode, specific settings for vehicle components may be preset, such as the position of cooling fins 5, the gear ratio of transmission system 102, etc.

[0093] In optional step M4, the operating status of vehicle 100 is determined. Figure 10 In the example shown, the operating state indicates the selected driving mode of the vehicle. If it is determined in step M4 that the controller 104 has selected "Sport Mode", as... Figure 10 If the "#" symbol is indicated, then proceed to step M61. If "efficiency mode" is determined in step M4, as shown... Figure 10 As indicated by the "*" symbol, proceed to step M63. If "Normal Mode" is determined in step M4, as shown... Figure 10 If the "+" symbol is indicated, then proceed to step M5.

[0094] In optional step M5, the temperature change rate of stator 2 and / or rotor 3 can be determined. Typically, the captured temperature can be checked in step M5. If step M5 is omitted or the temperature change rate of rotor 3 is determined to be below a predetermined threshold in step M5, such as... Figure 10 As indicated by the "+" symbol, the position of the cooling fin 5, such as the height h5 protruding from the outer side 4a of the end plate 4 and / or the orientation of the fin's longitudinal axis L5 relative to the radial direction R, can be controlled based on temperature (step M62). For example, functional dependence can define the orientation and / or height h5 for a specific temperature range. Control can be performed through open-loop or closed-loop control.

[0095] If in step M5 it is determined that the rate of temperature change of rotor 3 is equal to or greater than a predetermined threshold, such as Figure 10 If the "-" symbol is indicated, then the method proceeds to step M61.

[0096] In step M61, the cooling fins 5 are moved to a fully open position to increase heat transfer from the end plate 4 and in turn from the electric motor 1.

[0097] In step M63, the cooling fins 5 are moved to a closed position to minimize drag caused by the cooling fins 5.

[0098] Thus, generally in steps M61, M62 and M63, the airflow along the end plate 4 of the rotor 3 is varied (step M6) by moving the cooling fins 5 between the open and closed positions.

[0099] While the exemplary embodiments of the present application have been described and illustrated, it is to be understood that modifications can be made within the principles and central teachings of the present application, which are to be understood as being appended claims and equivalents thereof.

Claims

1. An electric motor (1) of a vehicle (100), comprising: a stator (2); a rotor (3) rotating relative to the stator (2) about a rotor rotation axis (A3) to generate a torque; an end plate (4) located at an axial end of the rotor (3) and coupled to the rotor (3) in a non-rotating manner; and a plurality of cooling fins (5) provided on the end plate (4), wherein the cooling fins (5) are moved relative to the end plate (4) such that a height (h5) of the cooling fins (5) protruding from the end plate (4) is adjustable.

2. The electric motor (1) according to claim 1, wherein the cooling fins (5) are moved relative to the end plate (4) such that an orientation of the cooling fins (5) relative to a radial direction R perpendicular to the rotor rotation axis (A3) is adjustable.

3. The electric motor (1) according to claim 1, the cooling fins (5) are linearly moved along the rotor rotation axis (A3) to change the height (h5) of the cooling fins (5) protruding from the end plate (4).

4. The electric motor (1) according to claim 3, wherein the cooling fins (5) are moved between a closed position in which the cooling fins (5) are provided flush with an outer side (4a) of the end plate (4) and an open position in which the cooling fins (5) protrude from the outer side (4a) of the end plate (4).

5. The electric motor (1) according to claim 3, wherein the cooling fins (5) are mounted to a carrier structure (6) and extend into a receiving opening (41), the carrier structure (6) is linearly guided along the rotor rotation axis (A3).

6. The electric motor (1) according to claim 2, wherein the cooling fins (5) are rotated about a fin rotation axis (A5) extending along the rotor rotation axis (A3).

7. The electric motor (1) according to claim 6, wherein the cooling fins (5) comprise a fin longitudinal axis (L5) which is rotated between a closed position in which the fin longitudinal axis (L5) extends transversely to the radial direction R and an open position in which the fin longitudinal axis (L5) extends along the radial direction R.

8. The electric motor (1) according to claim 6, further comprising: an operating mechanism (8) configured to rotate the cooling fins (5) synchronously.

9. The electric motor (1) according to claim 8, wherein the operating mechanism (8) comprises a central operating shaft (81), a central gear (82) mounted on the central operating shaft (81) and rotated by the central operating shaft (81), and a plurality of fin gears (83) coupled to the central gear (82), each fin gear (83) is coupled to a pin (84) defining a fin rotation axis (A5) of each cooling fin (5).

10. The electric motor (1) according to claim 1, wherein the cooling fins (5) are plate-shaped.

11. A vehicle (100), the vehicle (100) comprising the electric motor (1) according to claim 1.

12. The vehicle (100) according to claim 11, wherein The vehicle (100) is a road vehicle comprising at least one wheel (101) and a driveline (102) for rotating the at least one wheel (101), The electric motor (1) is mechanically coupled to the driveline (102) to supply torque to the driveline (102).

13. A method for cooling the electric motor (1) according to claim 1, comprising: a step Ml of rotating a rotor (3) of the electric motor (1); and a step M6 of moving the cooling fins (5) between an open position, in which the cooling fins (5) protrude from an end plate (4) of the rotor (3), and a closed position, in which the cooling fins (5) are arranged flush with the end plate (4) of the rotor (3), to vary the air flow along the end plate (4) of the rotor (3).

14. The method of claim 13, wherein, In the open position, the cooling fins (5) are oriented at least partially along a radial direction R extending perpendicularly to a rotor rotation axis (A3), in the closed position, the cooling fins (5) are arranged oriented transversely to said radial direction R.

15. The method according to claim 13, further comprising: a step M2 of capturing a temperature of at least one between the rotor (3) and the stator (2), wherein the step M6 of varying the air flow comprises a step of controlling a height (h5) of the cooling fins (5) protruding from the end plate (4) based on the captured temperature.

16. The method according to claim 14 or 15, wherein the step M6 of varying the air flow comprises a step of controlling an orientation of the cooling fins (5) with respect to the radial direction R based on the captured temperature.

17. The method according to claim 13, comprising: the control of said step M6 comprises performing an open loop control or a closed loop control.

18. The method according to claim 13, wherein, the electric motor (1) is a drive motor of a vehicle (100), the method further comprises a step M3 of capturing an operating condition of the vehicle (100), the step M6 of varying the air flow comprises a step of controlling the height of the cooling fins (5) protruding from the end plate (4) based on the captured operating condition.

19. The method of claim 14 or 18, wherein, the step M6 of varying the air flow comprises a step of controlling the orientation of the cooling fins (5) with respect to the radial direction R based on the captured operating condition. the step M6 of varying the air flow comprises a step of controlling the height of the cooling fins (5) protruding from the end plate (4) based on the captured operating condition. the step M6 of varying the air flow comprises a step of controlling the orientation of the cooling fins (5) with respect to the radial direction R based on the captured operating condition.

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