Axial flux motor drive device with two independent rotors sharing a single stator

Abstract

An axial flux motor drive for automobiles includes a stator defining a core, an output defining a rotation axis, a first rotor, a second rotor, and a thrust bearing. The first rotor is rotatable about the rotation axis, coupled to the output, and positioned relative to the stator to create a first air gap. The second rotor is rotatable about the rotation axis, coupled to the output, and positioned relative to the stator to create a second air gap. The thrust bearing is coupled to the output and supports an axial load substantially parallel to the rotation axis. The first rotor can still rotate about the rotation axis when the second rotor is inoperable, and the second rotor can still rotate when the first rotor is inoperable.

Description

Technical Field

[0001] This disclosure relates to an axial flux motor drive for automobiles. More specifically, this disclosure relates to an axial flux motor drive with two independent rotors sharing a single stator, wherein each rotor can operate independently of the other rotors. Background Technology

[0002] Electric motors are increasingly being used to drive vehicles, such as automobiles. It should be recognized that electric propulsion offers opportunities to enhance vehicle performance and vehicle dynamics control by individually operating the wheels and by increasing aerodynamics to improve or assist wheel traction. Specifically, to improve vehicle efficiency and power, motors are designed to be as compact and relatively lightweight as possible. Axial flux motors, especially in short-distance applications, offer excellent torque and power density and may be particularly suitable for driving vehicles. Specifically, an axial flux motor produces a magnetic flux parallel to the axis of its output shaft, hence the name. Conversely, a radial flux motor produces a radial flux relative to its output shaft, hence the name. The required package space for an axial flux motor is disc-shaped. The disc-shaped package space has a shorter and more compact form factor, making axial flux motors a potential candidate for use in confined spaces. Besides vehicles, axial flux motors can also be used in other applications, such as aircraft.

[0003] Therefore, although axial flux motors have achieved their intended purpose, there is still a need in the art for an axial motor with improved reliability to achieve high efficiency. Summary of the Invention

[0004] According to several aspects, an axial flux motor drive for automobiles is disclosed. The axial flux motor drive includes a stator defining an iron core, an output defining a rotation axis, a first rotor, a second rotor, and a thrust bearing. The first rotor is rotatable about the rotation axis and coupled to the output. The first rotor is disposed relative to the stator to create a first air gap between the stator and the first rotor. The second rotor is rotatable about the rotation axis and coupled to the output. The second rotor is disposed relative to the stator to create a second air gap between the stator and the second rotor. The thrust bearing is coupled to the output for supporting an axial load substantially parallel to the rotation axis, wherein the first rotor can still rotate about the rotation axis when the second rotor is inoperable, and the second rotor can still rotate when the first rotor is inoperable.

[0005] On the other hand, the stator also includes a first plurality of windings wound around a first part of the core.

[0006] On the other hand, in response to providing alternating current (AC) power to the first plurality of windings, a first magnetic flux is generated in the first air gap.

[0007] On the other hand, the axial flux motor drive also includes a first inverter that provides AC power to the first plurality of windings.

[0008] On the other hand, the stator also includes a second plurality of windings wound around the second part of the core.

[0009] On the other hand, in response to providing AC power to the second plurality of windings, a second magnetic flux is generated in the second air gap.

[0010] On the other hand, the axial flux motor drive also includes a second inverter that supplies AC power to a second plurality of windings.

[0011] On the other hand, the axial flux motor drive also includes a first planetary gear set coupled to the first output end, wherein the first planetary gear set includes a first sun gear, a first plurality of planet carriers and a first ring gear.

[0012] On the other hand, the first sun gear is a helical gear, comprising multiple teeth oriented at a first selected helix angle.

[0013] On the other hand, the axial flux motor drive also includes a second planetary gear set coupled to the second output end, wherein the second planetary gear set includes a second sun gear, a second plurality of planet carriers and a second ring gear.

[0014] On the other hand, the second sun gear is a helical gear, comprising a plurality of teeth oriented at a second selected helix angle.

[0015] In one aspect, the first output of the first planetary gear set rotates in a first direction, and the second output of the second planetary gear set rotates in a second direction, which is opposite to the first direction.

[0016] In another aspect, the axial flux motor drive also includes a one-way clutch coupled to the first rotor and the second rotor.

[0017] In one aspect, an axial flux motor drive for automobiles is disclosed. The axial flux motor drive includes a stator defining a core. The stator includes a first plurality of windings wound around a first portion of the core and a second plurality of windings wound around a second portion of the core. The axial flux motor drive also includes a first inverter supplying AC power to the first plurality of windings and a second inverter supplying AC power to the second plurality of windings. The axial flux motor drive also includes an output defining a rotation axis and a first rotor rotatable about the rotation axis and coupled to the output. The first rotor is disposed relative to the stator to create a first air gap between the stator and the first rotor, wherein a first magnetic flux is generated within the first air gap in response to supplying AC power to the first plurality of windings. The axial flux motor drive also includes a second rotor rotatable about the rotation axis and coupled to the output. The second rotor is disposed relative to the stator to create a second air gap between the stator and the second rotor, wherein a second magnetic flux is generated within the second air gap in response to supplying AC power to the second plurality of windings. The axial flux motor drive also includes a thrust bearing coupled to the output for supporting axial loads substantially parallel to the axis of rotation, wherein the first rotor can still rotate about the axis of rotation when the second rotor is inoperable, and the second rotor can still rotate when the first rotor is inoperable.

[0018] In one aspect, the axial flux motor drive also includes a first planetary gear set coupled to the first output end, wherein the first planetary gear set includes a first sun gear, a first plurality of planet carriers and a first ring gear.

[0019] On the other hand, the first sun gear is a helical gear, comprising a plurality of teeth oriented at a first selected helix angle.

[0020] On the other hand, the axial flux motor drive also includes a second planetary gear set coupled to the second output end, wherein the second planetary gear set includes a second sun gear, a second plurality of planet carriers and a second ring gear.

[0021] On the other hand, the second sun gear is a helical gear, comprising a plurality of teeth oriented at a second selected helix angle.

[0022] On the other hand, the first output of the first planetary gear set rotates in a first direction, and the second output of the second planetary gear set rotates in a second direction, which is opposite to the first direction.

[0023] On the other hand, the axial flux motor drive also includes a one-way clutch coupled to the first rotor and the second rotor.

[0024] Further applicability will become apparent from the description provided herein. It should be understood that the specification and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0025] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0026] Figure 1 This is a schematic diagram of one embodiment of an axial flux motor drive device for automobiles according to an exemplary embodiment;

[0027] Figure 2 This is a schematic diagram of an axial flux drive device including two planetary gear sets according to an exemplary embodiment;

[0028] Figure 3 This is a schematic diagram of a sun gear according to an exemplary embodiment, showing that the sun gear is... Figure 1 Part of one of the planetary gear sets shown;

[0029] Figure 4 This is an alternative embodiment of an axial flux motor drive device including a one-way clutch assembly according to exemplary embodiments; and

[0030] Figure 5 This is an alternative embodiment of the axial flux drive motor according to an exemplary embodiment. Detailed Implementation

[0031] The following description is merely exemplary in nature and is not intended to limit this disclosure, its application, or its uses.

[0032] refer to Figure 1 A cross-sectional schematic diagram of an automotive axial flux motor drive 10, including wheels 8 and tire assemblies 9, is shown. The disclosed axial flux motor drive 10 includes a single stator 20, two rotors 22, 24, an output 26 defining the rotation axis AA of the axial flux motor drive 10, and a thrust bearing 30. Specifically, the axial flux motor drive 10 includes a first rotor 22 and a second rotor 24. Figure 1 In the illustrated embodiment, output 26 includes a first shaft 28 coupled to a second shaft 29 via a thrust bearing 30. Thus, the thrust bearing 30 is coupled to output 26, allowing each rotor 22, 24 to operate independently of each other. Therefore, if one of rotors 22, 24 becomes inoperable, the remaining rotors 22, 24 can still operate. In one embodiment, the axial flux motor drive 10 is used in an automobile; however, it should be recognized that the axial flux motor drive 10 can also be used in other applications.

[0033] exist Figure 1In the illustrated embodiment, the output 26 of the axial flux motor drive 10 is connected to a single output via a one-way clutch assembly 16. Specifically, the single output (i.e., wheel 8) is connected to output 26 via the one-way clutch assembly 16. The one-way clutch assembly 16 includes a first optional one-way clutch 18 and a second optional one-way clutch 19, and the first optional one-way clutch 18 is coupled to a first rotor 22 via a first shaft 28, and the second optional one-way clutch 19 is coupled to a second rotor 24 via a second shaft 29. Figure 1 In the illustrated embodiment, the first shaft 28 is a sleeve shaft, the second shaft 29 is a stepped shaft, and the thrust bearing 30 is disposed at the step 31 defined by the second shaft 29. Now refer to... Figure 2 In another embodiment, the output 26 of the axial flux motor drive 10 is connected to two separate outputs. Specifically, the axial flux motor drive 10 is connected to a first output 46 and a second output 48. Figure 2 In the illustrated embodiment, the axial flux motor drive 10 can be applied to an aircraft, wherein the first output 46 and the second output 48 represent the top and bottom blades of the aircraft. Figure 2 In the embodiment shown, both the first shaft 28 and the second shaft 29 are solid shafts coupled to each other via a thrust bearing 30.

[0034] Continue to refer to Figure 2 The stator 20 defines a core 36. A first rotor 22 is rotatable about a rotation axis AA. The first rotor 22 is coupled to an output 26 and disposed relative to the stator 20 to create a first air gap 32 between the stator 20 and the first rotor 22. In the illustrated embodiment, the first air gap 32 is disposed between the upper surface 38 of the core 36 of the stator 20 and the lower surface 40 of the first rotor 22. A second rotor 24 is rotatable about a rotation axis AA and coupled to the output 26. The second rotor 24 is disposed relative to the stator 20 to form a second air gap 34 between the stator 20 and the second rotor 24. In the illustrated embodiment, the second air gap 34 is disposed between the lower surface 42 of the core 36 of the stator 20 and the upper surface 44 of the first rotor 22.

[0035] Continue to refer to Figure 2 The thrust bearing 30 is coupled to the output 26 and supports axial loads substantially parallel to the axis of rotation AA. The thrust bearing 30 allows each rotor 22, 24 to operate independently of each other. Therefore, when the second rotor 24 is inoperable, the first rotor 22 can still rotate about the axis of rotation AA; and when the first rotor 22 is inoperable, the second rotor 24 can still rotate.

[0036] The axial flux motor drive 10 also includes a first plurality of windings 50, a second plurality of windings 52, a first inverter 60, and a second inverter 62. The first plurality of windings 50 are wound around a first portion 56 of the stator core 36, and the second plurality of windings 52 are wound around a second portion 58 of the stator 20. The first inverter 60 is electrically coupled to the first plurality of windings 50 and provides them with alternating current (AC) power. Figure 2 As shown, in response to providing AC power to the first plurality of windings 50, a first magnetic flux 64 is generated within the first air gap 32. Similarly, a second inverter 62 is electrically coupled to the second plurality of windings 52 and provides AC power thereto. Figure 2 As shown, in response to providing AC power to the second plurality of windings 52, a second magnetic flux 68 is generated in the second air gap 34.

[0037] The first plurality of windings 50 and the first inverter 60 are electrically isolated from the second plurality of windings 52 and the second inverter 62. That is, the stator windings 50 and 52 are divided into two electrically independent systems, each powered by a separate inverter 60 and 62. Therefore, if the first plurality of windings 50 or the first inverter 60 becomes inoperable, the second rotor 24 remains inoperable. Similarly, if the second plurality of windings 52 or the second inverter 62 becomes inoperable, the first rotor 22 remains inoperable.

[0038] exist Figure 2 In the illustrated embodiment, the axial flux motor drive 10 includes a first planetary gear set 70 coupled to a first shaft 28 of output 26, and a second planetary gear set 74 coupled to a second shaft 29 of output 26. The first planetary gear set 70 includes a first sun gear 80, a first plurality of planet carriers 82, and a first ring gear 84. Similarly, the second planetary gear set 74 includes a second sun gear 90, a second plurality of planet carriers 92, and a second ring gear 94. The first planetary gear set 70 is connected to a first output 46, and the second planetary gear set 74 is connected to a second output 48.

[0039] In the illustrated non-limiting embodiment, a plurality of planetary carriers 82 are fixed, and a first output 46 is connected to a first ring gear 84; and a second ring gear 94 is fixed, and a second plurality of planetary carriers 92 are connected to a second output 48. Therefore, the planetary gear sets 70, 74 allow the first output 46 of the first planetary gear set 70 to rotate in a first direction, and the second output 48 of the second planetary gear set 74 to rotate in a second direction, wherein the second direction is opposite to the first direction. Although Figure 2 A plurality of fixed planetary carriers 82, a first output 46 connected to a first ring gear 84, a fixed second ring gear 94, and a second plurality of planetary carriers 92 connected to a second output 48 are shown. However, it should be recognized that... Figure 2This is merely an example; other connection methods can also be used to make rotors 22 and 24 rotate in opposite directions.

[0040] refer to Figure 3 In one embodiment, the first sun gear 80 is a helical gear 93, comprising a plurality of teeth 96 oriented at a first selected helix angle β1. The first selected helix angle β1 is selected to generate an axial force substantially parallel to the axis of rotation AA (see...). Figure 1 The magnetic force between the first rotor 22 and the stator 20 is counteracted in the axial direction. Specifically, the direction and value or magnitude of the first selected helix angle β1 are selected to generate the axial force. In one embodiment, the magnitude of the first selected helix angle β1 is selected to counteract the magnetic force between the first rotor 22 and the stator 20 under the most frequent operating conditions, for example, when a car or aircraft is running at cruising speed.

[0041] In an embodiment, the second sun gear 90 is a helical gear 98 and includes a plurality of teeth 100 oriented at a second selected helix angle β2, wherein the second selected helix angle β2 is selected to generate an axial force that counteracts the magnetic force between the second rotor 24 and the stator 20.

[0042] Figure 4 A one-way clutch assembly 16 coupled to a first rotor 22 and a second rotor 24 is shown. Specifically, the one-way clutch assembly 16 includes a first optional one-way clutch 18 coupled to the first rotor 22 and a second optional one-way clutch 19 coupled to the second rotor 24. Figure 4 As shown, a single output 122 is connected to a one-way clutch assembly 16. If one of the rotors 22, 24 is inoperable, the remaining rotors 22, 24 pass over the one-way clutch assembly 16. Therefore, even if one of the rotors 22, 24 is not working, the single output 122 can still rotate.

[0043] Figure 5 Another embodiment of the axial flux motor drive 10 used in an aircraft is shown. Figure 5 In the illustrated embodiment, the axial flux motor drive 10 includes a single stator 220, a single rotor 222, an output 226, and a thrust bearing 230. For example... Figure 5 As shown, multiple windings 250 are wound around a portion 256 of the core 236 of the stator 20, wherein an inverter 260 is electrically coupled to the multiple windings 250 and supplies AC power to them. A single rotor 222 is arranged relative to the stator 220 to create an air gap 232 between the stator 220 and the single rotor 222. It should be appreciated that, due to Figure 5 The axial flux motor drive device 10 shown includes a ratio Figure 1 , 2 The embodiment shown in Figure 4 has fewer components, so Figure 5 The method shown provides a low-cost solution.

[0044] like Figure 5 As shown, blade 270 is directly coupled to a single rotor 222, wherein blade 270 rotates cooperatively with the single rotor 222. Blade 270 generates lift, which manifests as an upward aerodynamic force 262. The aerodynamic force 262 generated by blade 270 cancels out a magnetic force 264 in the opposite direction or downward. Magnetic force 264 is generated in response to the inverter 260 supplying AC power to the multiple windings 250. It should be understood that aerodynamic force 262 can cancel out magnetic force 264, which is a function of the area and length of air gap 232. Reducing or eliminating magnetic force 264 can reduce or eliminate bearing losses and wear of thrust bearing 230. In an embodiment, a gear (not shown) may be used between the single rotor 22 and blade 270 to balance aerodynamic force 262 and magnetic force 264.

[0045] Referring generally to the accompanying drawings, the disclosed axial flux motor drive incorporates a variety of technical effects and benefits. Specifically, the axial flux motor drive has a short and compact form factor and includes two rotors that operate independently of each other. Therefore, if one rotor becomes inoperable, the other rotor can still operate. The axial flux motor drive also includes electrically separated windings and an inverter, which also allows one rotor to operate even if one inverter or winding is short-circuited or open-circuited. Finally, if the axial flux drive unit includes one or more planetary gear sets, the sun gear can include a selected helix angle to support some or all of the thrust load generated during operation, which further improves reliability.

[0046] The description in this disclosure is merely exemplary in nature, and variations thereof without departing from the spirit and scope of this disclosure are intended to fall within its scope. Such variations should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. An axial flux motor drive device for automobiles, comprising: One-way clutch; A stator with a defined iron core; An output defining a rotation axis, wherein the output includes a first shaft and a second shaft, the first shaft being a sleeve shaft and the second shaft being a stepped shaft defining a step, and wherein the output is connected to a single output via the one-way clutch; A first rotor, rotatable about the rotation axis, coupled to the output, and disposed relative to the stator to create a first air gap between the stator and the first rotor; A second rotor, rotatable about the rotation axis, coupled to the output, and disposed relative to the stator to create a second air gap between the stator and the second rotor; and A thrust bearing, coupled to the output, is used to support an axial load substantially parallel to the axis of rotation, wherein the first rotor can still rotate about the axis of rotation when the second rotor is inoperable, and the second rotor can still rotate when the first rotor is inoperable, and wherein the thrust bearing couples the first shaft to the second shaft, the thrust bearing being disposed at the step; A first planetary gear set coupled to a first end of the output, wherein the first planetary gear set includes a first sun gear, a first plurality of planet carriers and a first ring gear, wherein the first sun gear is a helical gear and includes a plurality of teeth oriented at a first selected helix angle, the first selected helix angle being selected to generate an axial force that counteracts the magnetic force between the first rotor and the stator in an axial direction substantially parallel to the axis of rotation; The one-way clutch includes a first one-way clutch and a second one-way clutch. The first one-way clutch is coupled to the first rotor through the first shaft, and the second one-way clutch is coupled to the second rotor through the second shaft.

2. The axial flux motor drive device according to claim 1, wherein, The stator also includes a first plurality of windings wound around a first portion of the core.

3. The axial flux motor drive device according to claim 2, wherein, In response to providing alternating current to the first plurality of windings, a first magnetic flux is generated in the first air gap.

4. The axial flux motor drive device according to claim 3 further includes a first inverter that provides AC power to the first plurality of windings.

5. The axial flux motor drive device according to claim 1, wherein, The stator also includes a second plurality of windings wound around a second part of the core.

6. The axial flux motor drive device according to claim 5, wherein, In response to providing AC power to the second plurality of windings, a second magnetic flux is generated in the second air gap.

7. The axial flux motor drive device according to claim 6 further includes a second inverter that provides AC power to the second plurality of windings.

8. The axial flux motor drive device according to claim 1 further includes a second planetary gear set coupled to the second end of the output, wherein, The second planetary gear set includes a second sun gear, a second plurality of planet carriers, and a second ring gear.

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