motor

Abstract

This disclosure relates to a rotor assembly for an electric motor, an electric motor including such a rotor assembly, a vehicle including such an electric motor, and a method of manufacturing such a rotor assembly. The rotor assembly includes a body member, a first shaft member, and a second shaft member. The body member includes an inner wall defining a cavity within the body member. The first shaft member is inserted into the body member and extends at least partially within the cavity of the body member. The second shaft member is inserted into the body member and extends from a first end of the body member to a second end of the body member. The second shaft member is at least partially surrounded by the first shaft member. The first shaft member is configured to provide a medium along the inner wall of the body member, and the second shaft member is configured to provide a medium at each of the first and second ends of the body member.

Description

Technical Field

[0001] This disclosure relates to a rotor assembly for an electric motor, an electric motor including such a rotor assembly, a vehicle including such an electric motor, and a method of manufacturing such a rotor assembly. Background Technology

[0002] Electric motors are used as traction motors in electric or hybrid vehicles. Traction motors in vehicles are typically configured to generate power to provide wheel torque to propel the vehicle and, if a regenerative braking system is used, recover braking energy. However, such motors can generate a significant amount of heat internally. For example, heat can be generated in the motor due to the resistance in the current flowing through the rotor and / or stator, hysteresis losses due to the changing magnetic field, and resistive heating from eddy currents induced by the magnetic field. Furthermore, heat is also generated due to mechanical friction between components within the motor.

[0003] However, in electric motors, the thermal capacity of the rotor magnets and stator windings affects the motor's usable output power. Rotor magnets typically have a thermal limit of 150°C, and demagnetization may occur when the temperature rises above this limit, thus reducing motor performance. Summary of the Invention

[0004] An improved motor that facilitates efficient heat transfer may be required.

[0005] The subject matter of this disclosure at least partially solves or alleviates this problem, wherein further embodiments are incorporated herein. It should be noted that the aspects of this disclosure described below apply to rotor assemblies for electric motors, electric motors including such rotor assemblies, vehicles including such motors, and methods of manufacturing such rotor assemblies.

[0006] According to this disclosure, a rotor assembly is proposed. The rotor assembly includes a body member, a first shaft member, and a second shaft member. The body member includes an inner wall defining a cavity within the body member. The first shaft member is inserted into the body member and extends at least partially within the cavity of the body member. The second shaft member is inserted into the body member and extends from a first end of the body member to a second end of the body member. The second shaft member is at least partially surrounded by the first shaft member. The first shaft member is configured to provide a medium along the inner wall of the body member, and the second shaft member is configured to provide a medium at each of the first and second ends of the body member.

[0007] The rotor assembly according to this disclosure can increase internal heat transfer by separately providing a medium within the cavity of the main body member. This medium can be in a gaseous state, a liquid state, or a mixture of gas and liquid. The medium can be water, oil, air, or water vapor, etc. The medium can be selected to suit heat transfer. By arranging two separate shaft members that provide the medium at separate locations within the main body member of the rotor assembly, effective distribution of the medium within the main body member can be achieved. Therefore, internal heat transfer of the rotor assembly can be significantly improved, and its performance can be enhanced.

[0008] The main body of the rotor assembly may be substantially cylindrical. The main body may include a plurality of magnets arranged around the outer surface of the main body. The magnets may be permanent magnets and are configured to rotate the main body due to electromagnetic energy. A cylindrical cavity may be formed between a first end and a second end, extending from the first and second ends of the main body. In other words, the main body may include inner walls extending from the first and second ends of the main body, thereby defining the cavity.

[0009] The first shaft member may be arranged at a first end or a second end of the main body member. The first shaft member may be manufactured separately and fixedly attached to the main body member, or it may be manufactured integrally with the main body member, thus forming a single piece. The first shaft member may extend from either the first or second end of the main body member in a direction toward the second or first end, respectively. Preferably, the first shaft member may extend substantially to the center of the rotor assembly. In other words, the length of the first shaft member may be less than the entire length of the main body member.

[0010] The second shaft member can be inserted into the first shaft member, and it can extend from one end of the main body member to the other end. The second shaft member can also be disposed separately in the first shaft member, or integrally manufactured with the first shaft member and / or the main body member. Since the length of the first shaft member can be less than the length of the main body member, the second shaft member can be surrounded only by the first shaft member for a corresponding length of the first shaft member, rather than by the entire length of the second shaft member. In other words, the second shaft member can be at least partially exposed within the cavity of the main body member.

[0011] The first and second shaft members may extend along the same longitudinal axis, which may correspond to the axis of rotation of the rotor assembly. However, they may also be arranged to deviate from the axis of rotation of the rotor assembly in the radial direction.

[0012] The first shaft member may include a first medium channel within it. The first shaft member may also include a shaft end exposed in a cavity of the body member. Therefore, the first shaft member can provide a medium through the first medium channel and dispense a medium through the shaft end. Because the shaft end of the first shaft member can be located at the center of the cavity, the first shaft member is capable of providing a medium substantially at the center of the cavity or the body member.

[0013] The second shaft member may further include a second medium channel to allow medium to flow within the second shaft member. The second medium channel of the second shaft member may be connected to each of the first and second ends of the main body member. Therefore, the first and second ends of the main body member may be provided with a medium independent of the first shaft member.

[0014] The medium provided by the first shaft member and the medium provided by the second shaft member can be the same, or they can include different components.

[0015] In one embodiment, the first shaft member includes at least one cavity medium dispersion element exposed within a cavity of the body member. To provide a medium within the cavity, the first shaft member may include a cavity medium dispersion element located at a shaft end of the first shaft member, which may be substantially exposed at the center of the cavity of the body member. Thus, the cavity medium dispersion element allows the medium supplied through a first medium channel of the first shaft member to be dispersed within the body member to improve heat transfer in the rotor assembly. The first shaft member may also include more than one cavity medium dispersion element surrounding the first shaft member.

[0016] The cavity medium dispersing element can be any suitable device for distributing the medium within the cavity, such as a nozzle, a jetting device, etc. The medium can be supplied from the first shaft member to the inner wall of the body member. The medium can then be further distributed along the inner wall of the body member in the direction of the first and / or second ends of the body member to transfer heat along the inner wall of the body member.

[0017] In one embodiment, the second shaft member includes a first media dispensing element disposed at a first end of the main body member and a second media dispensing element disposed at a second end of the main body member. The first and second media dispensing elements can be connected to a second media channel disposed in the second shaft member for providing media at each of the first and second ends of the main body member. The first and second media dispensing elements can be any suitable means of providing media, such as a nozzle, a jetting device, etc.

[0018] The medium supplied from the first and second medium distribution elements can be dispersed radially along the first and second ends of the main body member in the rotor assembly. Therefore, the first and second ends can be provided with a medium independent of the first shaft member.

[0019] In one embodiment, the cavity media dispersing element, the first media dispensing element, and / or the second media dispensing element include a nozzle element. The nozzle element may be arranged at the first and / or second shaft members in a direction perpendicular to the axis of rotation of the rotor assembly. Therefore, the nozzle element can provide media in the radial direction of the rotor assembly to effectively dispense media into the cavity of the body member. The nozzle element may be configured to regulate the flow rate and / or pressure of the media. For example, the nozzle element may be configured to increase the flow rate of the media exiting from the first and / or second shaft members, thereby generating turbulence in the media.

[0020] In one embodiment, the cavity media dispersing element, the first media dispensing element, and / or the second media dispensing element may include a jetting device. The jetting device may be configured to effectively disperse media from the first shaft member and / or the second shaft member into the cavity of the body member.

[0021] In one embodiment, a first end of the body member includes a first outlet element extending from the cavity to the outside of the body member, and a second end of the body member includes a second outlet element extending from the cavity to the outside of the body member. The first and second outlet elements may be formed as channels or holes extending from the cavity along the radial direction of the rotor assembly and configured to release media to the outside of the body member of the rotor assembly.

[0022] At each of the first and second outlet elements, the media dispersed from the first and second shaft members can combine and be released together from the main body member. The released media can be further used for heat transfer of components arranged outside the main body member of the rotor assembly, and / or the released media can be guided to a media circulation system.

[0023] In one embodiment, the rotor assembly further includes a hub element for separately providing the medium in the first shaft member and the second shaft member. In one embodiment, the hub element is arranged at a first end of the body member.

[0024] A hub element may be disposed at the end of a main body member on which both the first and second shaft members can be mounted. The hub element may preferably be arranged perpendicular to the axis of rotation of the rotor assembly. The hub element may be configured to separate the medium before it is supplied to the first and second shaft members. Therefore, the hub element may include a separate inlet for each of the first medium channel in the first shaft member and the second medium channel in the second shaft member. Thus, the first and second shaft members can independently transport the medium within the main body member.

[0025] In one embodiment, the hub element is connected to an actuator to supply media. The actuator may be a pump configured to continuously supply media to a first shaft member and a second shaft member at a predefined flow rate via the hub element. The actuator may be directly disposed at the hub element. Media released from the body member may be collected and directed to the actuator after a heat recovery process to allow for reliable circulation of the media.

[0026] In one embodiment, the medium may be oil. The oil can be any lubricant suitable for reducing friction and heat between contacting surfaces. Oil that can be supplied in droplet form allows for efficient heat transfer within the cavities of the rotor assembly.

[0027] According to this disclosure, an electric motor is proposed. The electric motor includes a stator unit and a rotor assembly as described above. The rotor assembly is arranged coaxially with the stator unit inside the stator unit.

[0028] An electric motor can be understood as an electromechanical converter that generates mechanical energy from electrical energy. The mechanical output, transmitted via a shaft, can act as a propulsion device for operating equipment. An electric motor may include a housing, a stator unit, and a rotor assembly that can be coaxially arranged within the housing, wherein the stator unit can be fixedly arranged within the housing, and the rotor assembly can be configured to rotate about the longitudinal axis of the motor within the stator unit. Each of the stator and rotor units may include multiple magnets, including permanent magnets or electromagnets comprising coil windings.

[0029] Therefore, the heat that may be generated in the motor due to resistance and / or mechanical friction between components can be transferred to the medium provided in the rotor assembly, and the motor can be effectively cooled. Thus, this medium can act as a coolant. Furthermore, the balance of the rotor assembly in the motor can be improved, and the inertia of the rotor assembly can be reduced.

[0030] In one embodiment, the rotor assembly is configured to release a medium from the body member to the stator unit via a first outlet element and / or a second outlet element. The medium released from the first and second outlet elements of the body member can be guided to the stator unit disposed outside the rotor assembly. Therefore, not only the rotor assembly but also the stator unit surrounding the rotor assembly can be cooled, and thermal management in the motor can be improved.

[0031] In one embodiment, the first end of the main body member of the rotor assembly is located on the non-drive side of the motor. The term "non-drive side" can be understood as one side of the motor that may not be connected to the drive unit of the device propelled by the motor. In one embodiment, the first shaft member, the second shaft member, and the hub element may also be arranged on the non-drive side of the motor. Therefore, medium distribution between the first shaft member and the second shaft member can be facilitated.

[0032] In one embodiment, a first shaft member of the rotor assembly is configured to cool the body member of the rotor assembly. A cavity medium dispersing element disposed at the shaft end of the first shaft member can be substantially exposed at the center of the cavity of the body member. Therefore, the cavity medium dispersing element allows the medium supplied through the first shaft member to be dispersed within the body member. Since the body member of the rotor assembly can be surrounded by multiple magnets, the medium can also cool the interior of the magnet elements.

[0033] In one embodiment, the second shaft member of the rotor assembly is configured to cool the windings of the stator unit. Extending from a first end to a second end of the body member, the second shaft member can directly deliver the medium to the stator unit via a first outlet element and a second outlet element. Therefore, the medium supplied by the second shaft member may not be dispersed within the cavity of the body member, but is instead guided directly to the stator unit while maintaining a low medium temperature.

[0034] Therefore, the motor according to this disclosure allows for individual and selective cooling of the main components of the rotor assembly and the stator unit with respect to operational requirements. By controlling the heat transfer between the rotor assembly and the stator unit, energy losses in the motor can be reduced, and the motor efficiency can be improved.

[0035] According to this disclosure, a vehicle is proposed. The vehicle includes an electric motor as described above. The vehicle is a battery-electric vehicle or a hybrid-electric vehicle. In such a vehicle, the electric motor can act as a traction motor that supplies power to the wheels to propel the vehicle. However, the traction motor may generate a significant amount of heat within itself. The vehicle according to this disclosure allows for improved thermal management of the electric motor by providing a separate coolant inflow within the rotor assembly of the motor.

[0036] According to this disclosure, a method for manufacturing a rotor assembly for an electric motor is proposed. The method includes:

[0037] A main component is provided, the main component including an inner wall defining a cavity inside the main component.

[0038] The first shaft member is inserted into the main body member, and the first shaft member extends at least partially within the cavity of the main body member.

[0039] The second shaft member is inserted into the main body member, the second shaft member extending from the first end of the main body member to the second end of the main body member, and

[0040] The second axis member is at least partially surrounded by the first axis member.

[0041] The first shaft member is configured to provide a medium along the inner wall of the main body member, and the second shaft member is configured to provide a medium at each of the first and second ends of the main body member.

[0042] It should be noted that the above embodiments can be combined with each other, regardless of the aspects involved. Therefore, the method can be combined with structural features, and similarly, the system can be combined with the features described above concerning the method.

[0043] These and other aspects of this embodiment will become apparent from the embodiments described below and will be illustrated with reference to the embodiments described below. Attached Figure Description

[0044] Exemplary embodiments will be described below with reference to the following figures.

[0045] Figure 1 Embodiments of an electric motor according to this disclosure are illustrated schematically and exemplary.

[0046] Figure 2 Embodiments of a hub element according to this disclosure are illustrated schematically and exemplary. Detailed Implementation

[0047] Figure 1 An electric motor 100 is shown, which can be installed in a battery electric vehicle (BEV) or a hybrid electric vehicle (HEV) to provide kinetic energy to the vehicle's wheels, thereby propelling the vehicle. Thus, the motor 100 acts as a traction motor; however, due to electromagnetic resistance or friction between the components of the motor 100, the traction motor generates a significant amount of heat. The motor 100 includes a stator unit 300 and a rotor assembly 200. The rotor assembly 200 is coaxially arranged inside the stator unit 300 and configured to rotate about the longitudinal axis of the motor 100, while the stator unit 300 is fixedly arranged.

[0048] The rotor assembly 200 includes a main body member 30, a first shaft member 10, and a second shaft member 20. The main body member 30 includes an inner wall 33 defining a cavity 34 within the main body member 30. The main body member 30 includes a first end 31 coupled to both the first shaft member 10 and the second shaft member 20, and a second end 32 coupled to the second shaft member 20. The first end 31 of the main body member 30 may be the non-drive end side of the motor 100.

[0049] The first shaft member 10 is inserted into the main body member 30 through a first end 31 and extends at least partially within a cavity 34 of the main body member 30. Preferably, the first shaft member 10 extends to the center of the main body member 30. The second shaft member 20 is also inserted into the main body member 30 through a first end 31 and extends from the first end 31 of the main body member to a second end 32 of the main body member 30. The second shaft member 20 is at least partially surrounded by the first shaft member 10.

[0050] Rotor assembly 200 also includes hub element 40 (see Figure 2A medium is provided separately in the first shaft member 10 and the second shaft member 20. This medium can be a coolant including water, oil, air, or water vapor. The medium can be selected to be suitable for heat transfer. The hub element 40 is arranged at the first end 31 of the main body member 30, which is the non-drive end side of the motor 100.

[0051] Hub element 40 is connected to an actuator, such as a pump (not shown), to continuously supply medium to the first shaft member 10 and the second shaft member 20 at a predefined flow rate. Hub element 40 includes at least one first shaft medium inlet 41 and at least one second shaft medium inlet 43. The first shaft medium inlet 41 is configured to supply medium in a first medium channel 12 of the first shaft member 10, and the second shaft medium inlet 43 is configured to supply medium in a second medium channel 23 of the second shaft member 20. Maximum cooling, in other words, heat homogenization, can be achieved by supplying medium via both the first shaft medium inlet 41 and the second shaft medium inlet 43.

[0052] The first shaft member 10 is configured to provide a medium along the inner wall 33 of the main body member 30, and the second shaft member 20 is configured to provide a medium at each of the first end 31 and the second end 32 of the main body member 30.

[0053] The first shaft member 10 includes at least one cavity medium dispersing element 11 exposed in a cavity 34 of the body member 30. The cavity medium dispersing element 11 is configured to dispense medium supplied through the first shaft member 10 into the cavity 34 of the body member 30, preferably in the center of the body member 30. Thus, the cavity medium dispersing element 11 and / or the first shaft member 10 are configured to cool the body member 30 of the rotor assembly 200.

[0054] The second shaft member 20 includes a first medium distribution element 21 disposed at a first end 31 of the main body member 30 and a second medium distribution element 22 disposed at a second end 32 of the main body member 30. The first medium distribution element 21 and the second medium distribution element 22 are configured to supply medium supplied through the second shaft member 20 to each of the first end 31 and the second end 32 of the main body member 30.

[0055] The first end 31 of the main body member 30 includes a first outlet element 35 extending from the cavity 34 to the outside of the main body member 30 (preferably extending to the stator unit 300), and the second end 32 of the main body member 30 includes a second outlet element 36 extending from the cavity 34 to the outside of the main body member 30 (preferably extending to the stator unit 300). The first outlet element 35 and the second outlet element 36 may be formed as channels extending from the cavity 34 of the main body member 30 in the direction of the stator unit 300. Therefore, the first outlet element 35 and the second outlet element 36 are configured to release a medium from the main body member 30 of the rotor assembly 200 to the stator unit 300. In other words, the second shaft member 20 is configured to cool the windings of the stator unit 300.

[0056] The cavity medium dispersing element 11, the first medium distribution element 21 and / or the second medium distribution element 22 include nozzle elements and / or injection devices to regulate the flow rate and / or pressure of the medium supplied through the first shaft member 10 and the second shaft member 20.

[0057] It should be noted that the embodiments described herein are referenced to different subject matters. In particular, some embodiments are described with reference to method type claims, while other embodiments are described with reference to device type claims. However, those skilled in the art will understand from the above and below description that, unless otherwise stated, any combination of features related to different subject matters, in addition to any combination of features belonging to one type of subject matter, is also considered to be disclosed with this application. However, all features can be combined to provide synergistic effects, rather than simply being a superposition of these features.

[0058] While this disclosure has been detailed and described in the accompanying drawings and specification, such descriptions should be considered illustrative or exemplary, and not restrictive. This disclosure is not limited to the disclosed embodiments. Other variations of the disclosed embodiments can be understood and implemented by those skilled in the art in practicing the claimed disclosure by studying the drawings, the disclosure, and the dependent claims.

[0059] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. A single processor or other unit can perform the function of several items referenced again in the claims. The fact that certain measures are referenced again in mutually different dependent claims does not mean that a combination of these measures cannot be used advantageously. Any reference numerals in the claims should not be construed as limiting the scope.

Claims

1. A rotor assembly (200) for an electric machine (100), comprising a body member (30), a first shaft member (10), a second shaft member (20), and a hub element (40), the body member (30) comprises an inner wall (33) defining a cavity (34) inside the body member (30), the first shaft member (10) is inserted into the body member (30) and extends at least partially in the cavity (34) of the body member (30), the second shaft member (20) is inserted into the body member (30) and extends from a first end (31) of the body member (30) to a second end (32) of the body member (30), the second shaft member (20) is at least partially surrounded by the first shaft member (10), the first shaft member (10) is configured to provide a medium along the inner wall (33) of the body member (30), the second shaft member (20) is configured to provide the medium at each of the first end (31) and the second end (32) of the body member (30); and the hub element (40) is configured to provide the medium individually by the first shaft member (10) and the second shaft member (20).

2. The rotor assembly (200) of claim 1, wherein, the first shaft member (10) comprises at least one cavity medium dispersing element (11) exposed in the cavity (34) of the body member (30), wherein the at least one cavity medium dispersing element (11) is a component that distributes the medium in the cavity (34).

3. The rotor assembly (200) of claim 1, wherein, the second shaft member (20) comprises a first medium distribution element (21) arranged at the first end (31) of the body member (30) and a second medium distribution element (22) arranged at the second end (32) of the body member (30), wherein the first medium distribution element (21) and the second medium distribution element (22) are components that provide the medium.

4. The rotor assembly (200) of claim 2 or 3, wherein, At least one of the cavity medium dispersing element (11), the first medium distribution element (21), or the second medium distribution element (22) comprises a nozzle element.

5. The rotor assembly (200) according to any one of claims 1-3, wherein, the first end (31) of the body member (30) comprises a first outlet element (35) extending from the cavity (34) to the outside of the body member (30) and the second end (32) of the body member (30) comprises a second outlet element (36) extending from the cavity (34) to the outside of the body member (30).

6. The rotor assembly (200) according to claim 1, the hub element (40) is arranged at the first end (31) of the body member (30).

7. The rotor assembly (200) according to any one of claims 1-3 or 6, the hub element (40) is connected to an actuator to supply the medium.

8. An electric machine (100), comprising a stator unit (300), and a rotor assembly (200) according to any one of the preceding claims 1 to 7, the rotor assembly (200) is arranged coaxially with the stator unit (300) within the stator unit (300).

9. The electric machine (100) according to claim 8, the rotor assembly (200) being configured to release a medium from the body member (30) to the stator unit (300) via the first outlet element (35) and / or the second outlet element (36).

10. The electric machine (100) of claim 8 or 9, wherein, A first end portion (31) of the body member (30) of the rotor assembly (200) is arranged at a non-drive side of the electric machine (100).

11. The electric machine (100) according to claim 8 or 9, the first shaft member (10) of the rotor assembly (200) being configured to cool the body member (30) of the rotor assembly (200).

12. The electric machine (100) according to claim 8 or 9, the second shaft member (20) of the rotor assembly (200) being configured to cool windings of the stator unit (300).

13. A vehicle comprising the electric machine (100) according to any one of the preceding claims 8 to 12, the vehicle being a battery electric vehicle or a hybrid electric vehicle.

14. A manufacturing method for a rotor assembly (200) of an electric machine (100), comprising providing a body member (30) comprising an inner wall (33) defining a cavity (34) inside the body member (30), providing a hub element (40), inserting a first shaft member (10) into the body member (30), the first shaft member (10) extending at least partially in the cavity (34) of the body member (30), inserting a second shaft member (20) into the body member (30), the second shaft member (20) extending from a first end portion (31) of the body member (30) to a second end portion (32) of the body member (30), and surrounding the second shaft member (20) at least partially by the first shaft member (10), the first shaft member (10) being configured to provide a medium along the inner wall (33) of the body member (30), the second shaft member (20) being configured to provide the medium at each of the first end portion (31) and the second end portion (32) of the body member (30), and the hub element (40) being configured to provide the medium individually by the first shaft member (10) and the second shaft member (20).

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