Lubricant supported motor with wheel support

Abstract

A lubricant supported electric motor includes a stator extending along an axis and a rotor rotatably disposed in surrounding and spaced apart relation about the stator to define at least one support cavity. A lubricant is disposed in the support cavity for supporting the rotor about the stator. A rim is fixedly connected to the rotor and forms a surrounding relation with the rotor and the stator. Thus, in a first aspect, rotation of the rotor is directly transmitted to the rim such that the rim rotates in accordance with rotation of the rotor. According to another aspect, the rotor is rotatably disposed within the stator and a planetary gear reduction mechanism is operably interconnected to the rotor, the stator and the rim and is configured to rotate the rim in response to rotation of the rotor within the stator.

Description

[0001] Cross-referencing related applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 62 / 752,442, filed October 30, 2018, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention generally relates to a lubricant-supported electric motor. More specifically, this invention relates to a lubricant-supported electric motor with an integrated wheel support. Background Technology

[0004] This section provides a general overview of the background information, and the comments and examples provided in this section are not necessarily prior art of the invention.

[0005] Various drivetrains in automobiles, trucks, and certain off-highway applications derive power from a central prime mover and distribute it to the wheels using mechanical devices such as transmissions, drive axles, drive shafts, and swivel shafts. These configurations work well when the prime mover can be large or bulky, such as various internal combustion engines (“ICE”). However, more attention is being focused on alternative prime mover configurations that offer improved environmental performance, eliminate mechanical drivetrain components, and result in lighter vehicles with more passenger and payload space.

[0006] "On-wheel," "in-wheel," or "near-wheel" motor configurations are alternative setups to traditional ICE prime movers that distribute prime mover functionality to each or some of the multiple wheels via one or more motors located on, inside, or near the wheels. For example, in one instance, a traction motor supporting the rotor using a central shaft passing through the rotor and rolling element bearings can be used as an "on-wheel," "in-wheel," or "near-wheel" motor configuration. In another example, a lubricated motor, such as that described in U.S. Application Serial No. 16 / 144,002, can be used as an "on-wheel," "in-wheel," or "near-wheel" motor configuration. While each of these motor configurations results in a smaller size and lighter weight compared to an internal combustion engine-based prime mover, each also has certain disadvantages and limitations.

[0007] For example, using a traction motor as an "on-wheel," "in-wheel," or "near-wheel" structure still results in a motor that is too heavy and not robust enough to withstand the load for wheel-end applications. In other words, the traction motor of the present invention is a large and heavy structure supported by rolling element bearings, which is too heavy and too large for wheel-end applications. Summary of the Invention

[0008] According to one aspect, the present invention relates to a lubricant-supported electric motor, the electric motor comprising: a stator extending along an axis; and a rotor extending along the axis and rotatably disposed around the stator in a radially surrounding and spaced relationship to define at least one support cavity extending between the stator and the rotor. Lubricant is disposed in the at least one support cavity for supporting the rotor around the stator. A rim is fixedly connected to the rotor and disposed in a relationship surrounding the rotor and the stator. Thus, in this aspect, rotation of the rotor is directly transmitted to the rim, such that the rim rotates in accordance with the rotation of the rotor. In other words, the rotor of the lubricant-supported electric motor directly supports the driven wheel.

[0009] According to another aspect, the present invention relates to a lubricant-supported electric motor, the electric motor comprising: a stator extending along an axis; and a rotor extending along the axis and rotatably radially disposed within the stator in a spaced-apart relationship to define at least one support cavity extending between the stator and the rotor. Lubricant is disposed in said at least one support cavity for supporting the rotor within the stator. A rim is disposed radially surrounding the stator and the rotor, and a planetary gear reduction mechanism is operatively interconnected with the rotor, the stator, and the rim, and configured to rotate the rim in response to rotation of the rotor within the stator.

[0010] Lubricated electric motors in any of these aspects are lightweight and thus contribute to overall design strategies for eliminating weight and size from automobiles and land vehicles. Further advantages will be appreciated in light of the following more detailed description of the invention. Attached Figure Description

[0011] The accompanying drawings described herein are for illustrative purposes only and are not intended to illustrate all possible embodiments, nor are they intended to limit the scope of the invention.

[0012] Figure 1 This is a schematic diagram of a lubricant-supported electric motor according to the present invention;

[0013] Figure 2 This is a cross-sectional view of the first aspect of a lubricated electric motor, showing a directly supported wheel; and

[0014] Figure 3 This is a cross-sectional view of another side of the lubricant-supported electric motor, showing the wheel-end motor with a reduction gear and the wheel supported by the gear ring of the reduction gear. Detailed Implementation

[0015] Exemplary embodiments of a lubricant-supported electric motor with integrated wheel support will now be described more fully. Each of these exemplary embodiments is provided so that the invention will thoroughly and completely convey the scope of the concepts, features, and advantages of the invention to those skilled in the art. For this purpose, numerous specific details, such as examples of specific components, devices, and mechanisms associated with the lubricant-supported electric motor, are set forth to provide a thorough understanding of each embodiment associated with the invention. However, as will be apparent to those skilled in the art, not all the specific details described herein are necessary to use, and exemplary embodiments may be implemented in many different forms and therefore should not be construed as limiting the scope of the invention.

[0016] Figure 1 A lubricant-supported electric motor 10 according to one aspect of the present invention is shown. For example... Figure 1 As best shown, the lubricant-supported motor 10 includes a stator 12 and a rotor 14, the rotor 14 extending along axis A and movably disposed within the stator 12 to define a support cavity or gap 16 therebetween. Lubricant 18 is disposed in the gap 16 to support the rotor 14 within the stator 12 and to provide continuous contact between these components. Therefore, the lubricant 18 can act as a buffer (e.g., suspension) between the rotor 14 and the stator 12, thereby minimizing or preventing contact between them. That is, the lubricant 18 prevents direct contact between the stator 12 and the rotor 14 and provides an electrolubricant-supported motor 10 that is resistant to shock and vibration loads due to the presence of the lubricant 18. Additionally and optionally, a substantially incompressible lubricant 18 may be used to minimize the gap between the stator 12 and the rotor 14.

[0017] like Figure 1 As further shown, the stator 12 defines a passage 20 configured to be in fluid communication with the gap 16 for introducing lubricant 18. However, the passage 20 can be provided on any other component of the lubricant-supporting motor 10 without departing from the disclosure of the invention. According to one aspect, the lubricant 18 can be circulated or pumped through the passage 20 and into the gap 16 in various ways. For example, a high-pressure source (e.g., a pump) 22 for the lubricant 18 can be fluidly connected to a low-pressure source (e.g., a reservoir) 24 for the lubricant 18, wherein the lubricant can move from the high-pressure source to the low-pressure source, through the passage 20, and into the gap 16. Rotation of the rotor 14 relative to the stator 12 can act as a self-pumping mechanism to drive the lubricant 18 through the passage 20 and into the gap 16.

[0018] like Figure 1As further shown, rotor 14 is interconnected with drive assembly 22 for connecting lubricated electric motor 10 to one of the vehicle's multiple wheels. For example, in one instance, drive assembly 22 may include a planetary gear system. Alternatively, drive assembly 22 may include one or more parallel shaft gears. Stator 12 and rotor 14 are configured to apply an electromagnetic force therebetween to convert electrical energy into mechanical energy, moving rotor 14 and ultimately driving the wheel coupled to lubricated electric motor 10 via drive assembly 22. Drive assembly 22 may provide one or more reduction ratios between lubricated electric motor 10 and the wheel in response to the movement of rotor 14.

[0019] Figure 1 The above-described aspects of the invention illustrate the illustrated embodiment, in which the stator 12 surrounds the rotor 14. However, the general operation of the lubricant 18 and the relationship between the stator 12 and the rotor 14 can be used in alternative arrangements of the rotor 14 and the stator 12, for example, where the rotor 14 is arranged radially outward from the stator 12, as further described below. In this case, the wheel structure can be supported by the rotor 14, rather than connecting the rotor 14 to a drive assembly that drives the wheel.

[0020] Reference Figure 2 The invention provides a wheel-end motor system 100 according to another aspect of the invention. System 100 may include wheels directly supported on a lubricant-supported motor 110. This configuration is ideal for monorail vehicles, such as scooters, where strong tipping moments on the wheels are reduced or eliminated.

[0021] System 110 may include a stator 112 and a rotor 114, the rotor 114 being movably disposed around the stator 112 along shaft A to define a gap or support cavity 116 between the stator 112 and the rotor. Lubricant 118 is disposed in the gap 116 to support the rotor 114 around the stator 112 and to provide continuous contact between these components. Thus, lubricant 118 can act as a buffer (e.g., suspension) between the rotor 114 and the stator 112, thereby minimizing or preventing contact between them. In other words, lubricant 118 prevents direct contact between the stator 112 and the rotor 114 and provides an electrolubricated motor 110 that is robust to shock and vibration loads caused by the presence of lubricant 118. Additionally and alternatively, a substantially incompressible lubricant 118 may be used to minimize the gap between the stator 112 and the rotor 114.

[0022] like Figure 2As further shown, stator 112 defines a passage 120 configured to be in fluid communication with gap 116 for introducing lubricant 118. However, passage 120 can be provided on any other component of the lubricant-supporting motor 110 without departing from the invention. According to one aspect, lubricant 118 can be circulated or pumped through passage 120 and into gap 116 in various ways. For example, a high-pressure source 121 (e.g., a pump) of lubricant 118 can be fluidly connected to a low-pressure source (e.g., a reservoir, not shown) of lubricant 118, wherein lubricant can move from the high-pressure source to the low-pressure source, through passage 120, and into gap 116. Rotation of rotor 114 relative to stator 112 can act as a self-pumping mechanism to drive lubricant 118 through passage 120 and into gap 116.

[0023] The stator 112 can be connected to or integrated with a shaft 123 extending coaxially with axis A. Shaft 123 can provide a passage 120a through which lubricant 118 passes between the pump 121 and the stator 112, supplying lubricant 118 to the gap 116. Shaft 123 can also define an outlet 125 in fluid communication with the gap 116. During operation of the motor 110, lubricant 118 can be discharged from the gap 116 and returned to the pump 121, replacing the used lubricant 118 with fresh lubricant 118. Therefore, lubricant 118 can circulate through the motor 110.

[0024] The lubricated motor 110 may also include a housing or enclosure 127 surrounding the stator 112. The housing 127 may be connected to the rotor 114 and thus may rotate with the rotor 114 during operation of the motor 110. The housing 127 may also include a sealed portion 129 that engages with the shaft 123 and / or the stator 112. Therefore, the housing 127 defines an inner cavity 131 configured to be in fluid communication with and may include a gap 116. The gap 116 generally refers to the radial region between the rotor 114 and the stator 112, but the gap 116 is in fluid communication with the remainder of the cavity 131, and lubricant in the gap 116 can freely flow into the remainder of the cavity 131. The aforementioned outlet 125 may intersect the cavity 131 at a location axially outward from the gap 116. When the rotor 114 rotates and the housing 127 rotates, the sealing portion 129 typically abuts against the shaft 123 and / or the stator 112, while retaining the lubricant 118 within the cavity 131, such that the lubricant 118 is restricted to leaving the cavity via the outlet 125.

[0025] Shaft 123 is preferably connected to a vehicle suspension or chassis (not shown) and does not rotate. Shaft 123 may include wiring channels or pathways 128 for receiving and routing wiring, etc., that can transmit current to stator 112. Stator 112 includes windings, etc., that receive current for generating an electric field to drive rotor 114. The current supplied to stator 112 may be a phase current.

[0026] exist Figure 2 In system 100, rotor 114 is rotatably fixed to wheel 122. Wheel 122 may be in the form of a rim 132 with a connected tire 134, or wheel 122 may include an outer surface designed to rest directly on the ground. Rotor 114 may be directly connected to wheel 122, or rotor 114 may be fixedly connected to wheel 122 via an intermediate structure. Figure 2 In the system, rotor 114 and wheel 122 are directly connected, allowing wheel 122 to be directly driven by motor 110.

[0027] Optionally, system 110 may include suspension elements radially disposed between rotor 114 and wheel 122 to provide damping characteristics. This suspension material may be in the form of a compliant wheel structure and allow wheel 122 to move radially relative to rotor 114, which serves as a hub. This additional damping material allows system 100 to be used in various vehicles, such as electric bicycles or golf carts, thereby eliminating or reducing other suspension components typically attached to axle 123.

[0028] As described above, lubricant 118 can be delivered to gap 116 (and cavity 131) via shaft 123 and stator 112. Stator 112 may include a lubricant passage 120 communicating with a corresponding lubricant passage 120a in shaft 123. Lubricant 118 circulates through system 100, wherein lubricant 118 is discharged from gap 116 and cavity 131 via outlet 125 in shaft 123 and returns to pump 121. Pump 121 may include known mechanisms for pumping fluid, and pump 121 may also include additional components for handling lubricant 118, such as a thermal control mechanism 136 that can cool or heat the lubricant to a desired temperature to control viscosity. Thermal control mechanism 136 may include sensor 138 and controller 140 for managing lubricant temperature. Pump 121 may also include a filtration mechanism that filters lubricant 118 to remove impurities, etc. Pump 121 may include sensors associated with the filtration mechanism to measure the state of the fluid and / or the filter.

[0029] The aforementioned system 100, which provides wheel support on the electric motor 110, reduces the overall size of the wheel-end system, so that the electric motor 110 does not need to be placed next to the wheel hub to drive the wheel.

[0030] Reference Figure 3On the other hand, system 200 includes a lubricated motor 210 having a stator 212 and a rotor 214. In this respect, the rotor 214 is disposed within the stator 212, similar to... Figure 1 The lubricant supports the motor 10 as shown. However, with Figure 1 Unlike the lubricant-supported motor 10, the gear reduction and wheel support are provided by a structure surrounding the rotor 214, which will be described further below.

[0031] The lubricant-supported motor 210 includes a gap or support cavity 216 radially disposed between the rotor 214 and the stator 212. The gap 216 is configured to receive lubricant 218 to support the rotor 214 within the stator 212. The lubricant 218 within the gap 216 can also be discharged from the gap 216 and circulated through the system 210 to a pump, etc. Figure 3 (Not shown in the image), similar to pump 121 of system 100.

[0032] The lubricated electric motor 210 also includes a gear reduction mechanism 222. The gear reduction mechanism 222 may be in the form of a planetary gear reduction mechanism, wherein a plurality of circumferentially fixed planetary gears P are arranged around a rotatable sun gear S, which causes the planetary gears P to rotate about their respective axes, such that the gear ring R around the planetary gears P rotates at a different speed than that of the sun gear S.

[0033] Planetary gear P is connected to planet carrier 223, which can be fixedly connected to the vehicle chassis. Planet carrier 223 can be considered an alternative to a shaft-type structure, or the chassis can include a shaft portion fixed to planet carrier 223. Planet carrier 223 is held in a substantially fixed position relative to the vehicle's axle / chassis. Planet carrier 223 may include a pair of outer body portions 223a supporting a plurality of circumferentially arranged pins 223b. Pins 223b are held in a substantially fixed position relative to planet carrier 223, and pins 223b support planetary gear P for rotation. Thus, each individual planetary gear P can rotate about an axis defined by pins 223b, which are supported on the planetary gear P.

[0034] The planetary carrier may also include an inner body portion 223c. The inner body portion 223c may have a generally axial position similar to that of the rotor 214 and stator 212, and the inner body portion 223c may have an annular shape for supporting pin 223b, similar to the outer body portion 223a. Therefore, pin 223b extends axially between the outer body portion 223a and the inner body portion 223c. The inner body portion 223c, together with the outer body portion 223a and pin 223b, remains stationary during operation of the motor 210.

[0035] The stator 212 is mounted on or fixedly connected to the inner body portion 223c. The stator 212 can be integrally formed with the inner body portion 223c, or it can be a separate component. The stator 212, including windings, can be disposed radially inward from the inner body portion 223c, such that the stator 212 is radially located between the inner body portion 223c and the rotor 214. In another method, the stator 212 can be mounted or connected to the inner body portion 223c, such that the inner body portion 223c is radially disposed between the stator 212 and the rotor 214. In this method, the distance between the rotor 214 and the stator 212 is small enough that the current applied to the stator 212 will still effectively rotate the rotor 214.

[0036] The stator 212 and planetary carrier 223 are thus combined to define a fixed structure within which the rotor 214 is disposed. Lubricant 218 can be supplied to the lubricant-supported motor 210 and discharged from the motor 210 via fluid passages 224 provided in both the planetary carrier 223 and the stator 212. The fluid passages 224 may extend through one or more pins 223b.

[0037] The reduction mechanism 222 includes the aforementioned gear ring R. The gear ring R has a generally annular shape and surrounds the planetary gear P circumferentially and radially. Therefore, the gear ring R has internal teeth that mesh with the external teeth of the planetary gear P. The gear ring R can be in an axially external form, which is disposed on the opposite axial sides of the rotor 214 and the stator 212. The gear ring R rotates in response to the rotation of the planetary gear P.

[0038] A gear ring R is fixedly connected to a rim 225, which surrounds the inner body portion 223c, the stator 212, and the rotor 214. Therefore, the rim 225 will rotate around the inner body portion 223c, which is fixed to the stator 212 and the planetary carrier 223, in accordance with the rotation of the gear ring R. The gear ring R and the rim 225 will also rotate around the rotor 214, which is located at the radial center of the motor 210. The rim 225 can support a tire attached thereto. Figure 3 (not shown in the image), or the rim 225 may include a wheel structure configured to engage the ground in place of a separate tire.

[0039] As described above, lubricant 218 is disposed in a gap 216 between the rotor 214 and the internal main body portion 223c of the stator 212 or planetary carrier 223, the planetary carrier 223 supporting the stator 212. Figure 3As shown, the lubricant 218 may also be radially disposed in the outer gap 216a between the rim 225 and the inner body portion 223c or the stator 212 (radially disposed near the rim 225). The lubricant 218 may be delivered to the outer gap 216a via a channel 224 extending through the stator 212 and the inner body portion 223c, or the lubricant 218 may reach the outer gap 216a through other fluid channels defined within the lubricant-supported motor 210.

[0040] System 200 may include a sealing portion 227 extending between the outer surface 223a of planetary carrier 223 and the gear ring R, wherein the sealing portion 227 is secured to the outer surface 223a or the gear ring R. The sealing portion 227 seals the interior of the lubricant-supported motor 210 and retains lubricant 218 therein, such that the lubricant is confined to exit the lubricant-supported motor 210 via a discharge passage. System 200 may also include a wiring channel or passage 230 extending through pin 223b and the interior body portion 223c of planetary carrier 223 for receiving and routing wiring, etc., to deliver current to stator 212.

[0041] As described above, rotor 214 is disposed within stator 212 and supported by lubricant 218. Rotor 214 can therefore rotate relative to stator 212 in response to the supply of current to stator 212. Rotor 214 is fixedly connected to sun gear S, which has external teeth configured to engage the external teeth of planetary gear P. When rotor 214 rotates, sun gear S rotates accordingly with rotor 214. The rotation of sun gear S causes planetary gear P to rotate about their respective axes, which in turn causes rotation of ring gear R and rim 225.

[0042] Therefore, the wheel rim 225 is directly supported by the reduction gear 222, particularly the gear ring R, and the reduction gear is directly supported and connected to the lubricated motor 210. Specifically, the stator 212 is supported by or supports the inner body portion 223c of the planetary carrier 223. Thus, the system 200 can provide integral gear reduction, allowing for smaller components and eliminating additional connecting parts that would otherwise connect the motor to the reduction gear further connected to the wheel.

[0043] The above description of embodiments has been provided for illustrative and descriptive purposes. It is not intended to be exhaustive or limiting of the invention. Various elements or features of a particular embodiment are generally not limited to that particular embodiment; however, they may be interchanged where applicable and may be used in selected embodiments even if not specifically shown or described. Variations are also possible. Such variations are not considered to depart from the scope of the invention, and all such modifications are intended to be included within the scope of the invention.

Claims

1. A lubricant-supported electric motor, characterized in that, include: Stator, which extends along an axis; A rotor extending along the axis and rotatably radially disposed within the stator at intervals to define at least one support cavity extending between the stator and the rotor; A lubricant disposed in at least one of the support cavities for supporting the rotor within the stator; The rim is arranged radially around the stator and the rotor; A planetary carrier interconnected to the stator and defining a plurality of pins arranged in a circumferentially fixed relationship around the axis; A planetary gear reduction mechanism operatively interconnected to the rotor, the stator and the rim, and configured to rotate the rim in response to rotation of the rotor within the stator; The planetary gear reduction mechanism includes a sun gear disposed along the axis, a plurality of planetary gears meshing with the sun gear and disposed circumferentially around the sun gear and rotatably supported by a corresponding pin of a plurality of pins to establish an operable connection between the stator and the plurality of planetary gears, and a gear ring meshing with the plurality of planetary gears and disposed circumferentially around the plurality of planetary gears. The rotor is interconnected with the sun gear, the stator is interconnected with the plurality of planetary gears, and the rim is interconnected with the ring gear to establish an operable interconnection of the planetary gear reduction mechanism; The stator defines at least one passage, and the at least one passage is configured to be in fluid communication with at least one of the support cavities; The planetary carrier defines at least one channel, the at least one channel extending through the plurality of pins and being configured to be in fluid communication with at least one of the passageways; A pump configured to be in fluid communication with at least one of the channels for continuously pumping the lubricant through at least one of the channels and at least one of the passages to at least one of the support cavities; as well as The planetary carrier includes an inner body portion and an outer body portion. The inner body portion is disposed within the rim and axially aligned with the rotor and the stator. The outer body portion is disposed axially outside the inner body portion and spaced apart from the inner body portion. Each of the plurality of pins extends between the inner body portion and the outer body portion.

2. The lubricant-supported electric motor as described in claim 1, characterized in that, The inner main body portion is radially disposed between the stator and the rim.

3. The lubricant-supported electric motor as described in claim 1, characterized in that, The outer body portion is fixedly connected to the vehicle chassis.

4. The lubricant-supported electric motor as described in claim 1, characterized in that, It also includes a seal extending between the outer body portion of the gear ring and the planetary carrier for retaining the lubricant within the support cavity.

5. The lubricant-supported electric motor as described in claim 1, characterized in that, The inner body portion of the planetary carrier is spaced apart from the rim to define an external clearance, and at least one of the passages of the stator is configured to be in fluid communication with the external clearance so that, in addition to the support cavity, lubricant is also delivered to the external clearance.

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