HK40113014A - Multi-bar linkage electric drive system - Google Patents

Description

Multi-link electric drive system

Related applications

This application is a divisional application of patent application No. 202011611397X (title of invention: Multi-link Electric Drive System), filed on December 30, 2020 (during the substantive examination of that patent application, the examiner issued a first office action on April 29, 2023, noting a deficiency in unity of invention). The patent application No. 202011611397X (title of invention: Multi-link Electric Drive System) is a divisional application of patent application No. 2017800561614 (title of invention: Multi-link Electric Drive System), filed on March 13, 2019. The aforementioned patent applications claim the benefits of U.S. Provisional Application No. 62/393,982, filed on September 13, 2016, and U.S. Provisional Application No. 62/512,469, filed on May 30, 2017.

Technical Field

The embodiments generally relate to electric motor drive assemblies, and more specifically, to electric motor drive assemblies capable of producing wheel movements with two degrees of freedom, such as rotational movement of the wheel and translational movement of the wheel in a direction transverse to the wheel's axis of rotation.

Background Technology

More and more companies are developing vehicles that use electric motors as the means of propulsion. And because electric motors can be designed to be extremely compact and efficient, especially compared to combustion engines, they are also used as in-wheel or in-hub motors, where the motor is installed in or very close to each wheel of the vehicle. Some of the newer, more innovative designs for vehicle drivetrains not only enable the wheels to rotate but also to move them laterally to the axis of rotation. That is, they can produce movement with two degrees of freedom: rotation that propels the vehicle along the road and translation that provides active suspension for the vehicle.

An example of such a system is described in U.S. 8,519,575 and is based on the use of Lorentz force and linear actuators. To achieve the two degrees of freedom, it uses two opposing linear actuators and a linear-to-rotation converter, which consists of an arrangement of cam followers engaging with a cam assembly supporting the wheel rim. The linear actuators are opposite each other because they are located on opposite sides of the wheel's axis of rotation. When the two opposing linear actuators are operated to move the cam followers synchronously toward or away from each other, the linear-to-rotation converter converts this movement into pure rotation of the wheel. When the two linear actuators are operated to move the cam followers in the same direction (i.e., one toward the axis of rotation and the other away from it), this causes the cam assembly and the wheel to which it is attached to to translate in a direction transverse to the wheel's axis of rotation.

Summary of the Invention

In general, in one aspect, the present invention provides an electric drive system comprising a rotary motor system and a multi-link mechanism. The rotary system includes a hub assembly, a first rotary assembly, a second rotary assembly, and a third rotary assembly, wherein the hub assembly defines a rotation axis, and each of the first, second, and third rotary assemblies is coaxially aligned with the rotation axis and is capable of rotational movement about the rotation axis independently of the other two. The multi-link mechanism is connected to each of the first and third rotary assemblies and to the hub assembly, and constrains movement of the hub assembly such that the rotation axis of the hub assembly moves along a defined path in a lateral direction relative to the rotation axis. The multi-link mechanism causes the rotation axis of the hub assembly to translate along the defined path in response to relative rotation of the first and third rotary assemblies relative to each other.

In general, in another aspect, the present invention provides an electric drive system comprising a rotary motor system and a multi-link system. The rotary motor system includes a hub assembly, a magnetic rotor assembly, a first coil stator assembly, and a second coil stator assembly, wherein the hub assembly defines a rotation axis, and each of the magnetic rotor assembly, the first coil stator assembly, and the second coil stator assembly is coaxially aligned with the rotation axis and is rotatably movable about the rotation axis independently of each other. The multi-link mechanism is connected to each of the first and second coil stator assemblies and to the hub assembly. The multi-link mechanism constrains the movement of the hub assembly such that the rotation axis of the hub assembly moves along a defined path in a lateral direction relative to the rotation axis, and the multi-link mechanism causes the rotation axis of the hub assembly to translate along the defined path in response to the relative rotation of the first and second coil stator assemblies relative to each other.

Other embodiments may include one or more of the following features. The multi-link mechanism is a four-bar linkage, such as a Watt's linkage. The multi-link mechanism includes a support structure, a crankshaft assembly, a first rocker arm, and a second rocker arm, wherein the first rocker arm has a first end rotatably connected to the crankshaft assembly and a second end rotatably connected to the support structure at a first position on the support structure, and wherein the second rocker arm has a first end rotatably connected to the crankshaft assembly and a second end rotatably connected to the support structure at a second position on the support structure, the second position being different from the first position on the support structure. The crankshaft assembly includes the hub assembly. The crankshaft assembly includes a crankshaft, a first crank arm extending from the crankshaft in a first radial direction, and a second crank arm extending from the crankshaft in a second radial direction. The first crank arm and the second crank arm are located at opposite ends of the crankshaft. The first radial direction is opposite to the second radial direction.

Other embodiments may include one or more of the following features. The electric drive system further includes a first torque link connecting the first coil stator assembly to the first swing arm and a second torque link connecting the second coil stator assembly to the second swing arm. It also includes a rim surrounding a rotation axis, wherein the magnetic rotor assembly is coupled to the rim such that the rim, together with the magnetic rotor assembly, rotates about the rotation axis. The rim also surrounds the rotary motor system. The rotary motor system includes: a first motor comprising a first magnetic rotor, a first coil stator assembly, a rotor bearing assembly enabling the first magnetic rotor to rotate about the rotation axis, and a first coil bearing assembly enabling the first coil stator assembly to rotate independently of the first magnetic rotor about the rotation axis; and a second motor comprising a second magnetic rotor, a second coil stator assembly, and a second coil bearing assembly, the second coil bearing assembly enabling the second coil stator assembly to rotate independently of the first magnetic rotor and independently of the first coil stator assembly about the rotation axis, wherein the magnetic rotor assembly includes first and second magnetic rotors coupled to each other to rotate together about the rotation axis. The first and second motors are axial flux motors.

In general, in another aspect, the present invention provides a vehicle comprising a chassis and a plurality of wheel assemblies. At least one of the wheel assemblies includes a rotary motor system comprising a hub assembly, a magnetic rotor assembly, a first coil stator assembly, and a second coil stator assembly, wherein the hub assembly defines a rotation axis, and each of the magnetic rotor assembly, the first coil stator assembly, and the second coil stator assembly is coaxially aligned with the rotation axis and is rotatably movable about the rotation axis independently of each other. It also includes a multi-link mechanism connected to each of the first and second coil stator assemblies and connected to the hub assembly. The multi-link mechanism constrains the movement of the hub assembly such that the rotation axis of the hub assembly moves along a defined path in a lateral direction relative to the rotation axis, and the multi-link mechanism causes the rotation axis of the hub assembly to translate along the defined path in response to the relative rotation of the first and second coil stator assemblies relative to each other. The wheel assembly further includes a rim surrounding the axis of rotation, and wherein the magnetic rotor assembly is coupled to the rim such that the rim, together with the magnetic rotor assembly, rotates about the axis of rotation.

Other embodiments of the wheel assembly may include one or more of the following features. The multi-link mechanism is a four-bar linkage, such as a Watt's linkage. The multi-link mechanism includes a support structure, a crankshaft assembly, a first control arm, and a second control arm, wherein the first control arm has a first end rotatably connected to the crankshaft assembly and a second end rotatably connected to the support structure at a first position on the support structure, and wherein the second control arm has a first end rotatably connected to the crankshaft assembly and a second end rotatably connected to the support structure at a second position on the support structure, the second position being different from the first position on the support structure. The crankshaft assembly includes the hub assembly. The crankshaft assembly includes a crankshaft, a first crank arm extending from the crankshaft in a first radial direction, and a second crank arm extending from the crankshaft in a second radial direction. The first crank arm and the second crank arm are located at opposite ends of the crankshaft. The first radial direction is opposite to the second radial direction. At least one wheel assembly further includes a first torque link connecting the first coil stator assembly to the first swing arm and a second torque link connecting the second coil stator assembly to the second swing arm. The rotary motor system includes a first electric motor comprising a first magnetic rotor, a first coil stator assembly, a rotor bearing assembly enabling the first magnetic rotor to rotate about a rotation axis, and a first coil bearing assembly enabling the first coil stator assembly to rotate independently of the first magnetic rotor about the rotation axis. The rotary motor system also includes a second electric motor comprising a second magnetic rotor, a second coil stator assembly, and a second coil bearing assembly, the second coil bearing assembly enabling the second coil stator assembly to rotate independently of the first magnetic rotor and independently of the first coil stator assembly about the rotation axis, wherein the magnetic rotor assembly comprises first and second magnetic rotors connected to each other to rotate together about the rotation axis.

Attached Figure Description

The foregoing will become clear from the following more detailed description of the exemplary embodiments, as illustrated in the accompanying drawings, in which the same reference numerals refer to the same parts in different views. The drawings are not necessarily drawn to scale, but are intended to illustrate the embodiments.

Figure 1 is a schematic diagram showing the Watt linkage.

Figure 2 is a diagram showing an example translation path of the center point of the Watt link in Figure 1.

Figure 3 is a schematic representation of an embodiment of the Watt linkage drive system.

Figures 4A to 4D are a series of schematic diagrams showing the translational movement of the components of the Watt linkage system in Figure 3.

Figure 5A schematically illustrates another embodiment of a multi-link drive system.

Figure 5B shows the multi-link drive system of Figure 5A, in which a section of the rotor and a section of the stator are removed to make the other stator visible.

Figures 6A to 6F are a series of schematic representations illustrating the translational movement of the multi-link drive system shown in Figures 5A and 5B.

Figure 7 shows components of a dual-motor axial flux drive mechanism, for example, that can be used in the multi-link drive system shown in Figures 5A and 5B.

Figure 8 is a perspective view of a multi-link drive system used in vehicles.

Figure 9 is a perspective view of the multi-link drive system shown in Figure 8, with some components removed to reveal the internal structure.

Figure 10 is a perspective view of the multi-link structure used in the multi-link transmission system of Figure 8.

Figures 11A and 11B are orthogonal and perspective cross-sectional views of the dual-motor axial flux drive system used in the multi-link drive system shown in Figure 8, with the coil stator assembly removed.

Figures 12A and 12B are orthogonal and perspective cross-sectional views of an axial flux motor shown in Figures 11A-B, which includes the coil stator assembly.

Figure 13 is a schematic diagram showing a vehicle using the multi-link drive system shown in Figure 8.

Figure 14 shows another embodiment of the integrated wheel and suspension assembly.

Figure 15 is a schematic cross-sectional view of the axial flux motor used in the integrated wheel and suspension assembly of Figure 14.

Figure 16 is a schematic front view of the axial flux motor used in the integrated wheel and suspension assembly of Figure 14.

Figure 17 is a schematic cross-sectional view of the integrated wheel and suspension assembly shown in Figure 14.

Figures 18A and 18B are schematic side views of the integrated wheel and suspension assembly of Figure 14, showing the operation of the linkage arrangement during common-mode operation.

Figure 19 is a schematic side view of the integrated wheel and suspension assembly of Figure 14, showing the operation of the linkage arrangement during differential mode operation.

Figures 20A and 20B present the arrangement shown in Figures 18A and 18B in terms of interconnecting links.

Figure 21 shows an alternative arrangement of the linkage between the coil stator assembly and the suspension arm.

Figure 22 shows details of the linear bearing to which the main shaft is connected in the suspension arm.

Figure 23 shows a vehicle using the drivetrain shown in Figure 19.

Figure 24 shows an alternative arrangement of bearings for the electric motor depicted in Figure 15.

Figures 25A-C show alternative guiding mechanisms that use a rocker arm to define the path on which the axis of rotation can move laterally.

Detailed Implementation

The example implementation is described below.

Figure 1 is a schematic diagram illustrating a Watt's linkage 100. A Watt's linkage is a mechanical linkage arrangement in which the center point 105 of one of the linkages is constrained by the linkage to travel along a predefined path, most of which is substantially straight, as indicated by line 110. The Watt's linkage comprises three movable links; in this particular example, two longer links 115 and 120 of equal length are connected together by a shorter link 125, the midpoint of which is point 105. The ends of the three links are hinged so that they can rotate about the hinge point. One end of link 115 is connected to a fixed mount 126 at hinge point 127, and the other end of link 115 is connected to one end of the shorter link 125 at hinge point 128. One end of link 120 is connected to the other end of the shorter link 125 at hinge point 129, and the other end of link 120 is connected to a second fixed mount 130 at another hinge point 131. Fixed mounts 126 and 130 are secured in place relative to each other by, for example, coupling to a common base or common structure. Although there are only three movable rods in this example, Watt's linkage is often referred to as a four-bar linkage because the connection between the two fixed mounts is considered the fourth rod.

As is evident from Figure 1, even though the ends of the rods are constrained by their connection to each other, the orientation of the rods can be changed. Therefore, for example, suppose the initial position of the rods is as shown by the element depicted in solid lines. When rod 115 is rotated counterclockwise relative to hinge point 127 to another position indicated by the dashed line marked A in the figure, rod 120 will rotate clockwise about its hinge point 131, and short rod 125 will rotate clockwise relative to its center point. Alternatively, if rod 115 is rotated clockwise to another position indicated by the dashed line marked B in the figure, rod 120 will rotate counterclockwise, and short rod 125 will also rotate counterclockwise relative to its center point. The characteristic of the Watt's linkage is that as the orientation of the rods is changed in this way to cover all possible orientations allowed by the linkage arrangement, the center point 105 of short rod 125 will trace a defined path, and the Watt's linkage arrangement constrains said center point to always lie on said defined path. As shown in Figure 2, the defined path is shaped like a figure 8, and is mostly linear.

The embodiment shown in Figure 3 uses a Watt's linkage combined with two electric motors to construct a transmission system 300, which can drive a wheel (not shown) in a rotational manner and controllably translate the wheel in a direction transverse to the wheel's axis of rotation. In other words, it is a transmission system with two degrees of freedom.

The transmission system 300 includes two electric motors 340 and 345 (shown as two triangular objects) fixed in place relative to each other. It also includes a linkage arrangement consisting of two equal-length swing arms 315 and 320 and a shorter crank arm 325. These correspond respectively to the rods 115, 120, and 125 shown in Figure 1 previously discussed. At one end of the swing arm 315 is a pulley 350 driven by the electric motor 340, and at the distal end of the swing arm 320 is another pulley 355 driven by the electric motor 345. At the other end of the swing arm 315 opposite the end with the pulley 350, there is a second pulley 358. A coaxially aligned elbow gear 360 is attached to said pulley 358. Similarly, at the other end of the swing arm 320 opposite the end with the pulley 355, there is also a pulley 363 with another attached coaxially aligned elbow gear 365, which is the same size as the elbow gears 360 and 365. A crank gear 370 is located at the center point of the crank arm 325, and meshes with two elbow gears 360 and 365. On the rocker arm 315, a drive belt 375 connects pulley 350 to pulley 358, and on the rocker arm 320, another drive belt 380 connects pulley 355 to pulley 363. Pulleys 350 and 358 have the same gear ratio as pulleys 355 and 363.

To understand the operation of the linkage system 300 in Figure 3, consider this scenario: two motors 340 and 345 rotate their attached pulleys 350 and 355 at the same rate and in the same direction (e.g., clockwise). In this case, belt 375 will also drive gear 360 clockwise at a speed determined by the ratio of the sizes of the two pulleys 350 and 358. Similarly, belt 380 will drive gear 365 clockwise at a speed determined by the ratio of the sizes of those two pulleys 355 and 363. Assuming the two sets of pulleys (i.e., pulleys 350 and 358 and pulleys 355 and 363) have a 1:2 ratio, when motor 340 drives pulley 350 clockwise at a rotational speed of 2ω, pulley 358 will rotate clockwise at half that speed, i.e., ω. Since gears 360, 365, and 370 have the same ratio, gear 370 and its attached drive shaft 372 will ideally rotate counterclockwise at a speed ω. Similarly, when motor 345 drives pulley 355 clockwise at a rotational speed 2ω, pulley 363 will rotate clockwise at half that speed, ω, and gear 370 and its attached drive shaft 372 will also ideally rotate counterclockwise at a speed ω. Note that this operating condition, where the motors operate at the same speed, causes both motors to rotate gear 370 at ω, resulting in zero torque applied to the crank arm 325 supporting crank gear 370. That is, operating motors 340 and 345 at the same speed and in the same direction will cause the transmission system to produce a pure rotational movement of the drive shaft. Since no torque is applied to any link, they will not change their orientation or position. Therefore, under those drive conditions, the swing arms 315 and 320 will remain fixed and "locked" in place.

From the above discussion, it should be clear that different situations arise when the motors operate at different speeds. In this case, torque will be applied to the crank arm, and this torque will cause a change in the orientation of the connecting rod. To understand why, consider what happens in the above situation when motor 345 increases its speed to slightly above 2ω. When this happens, gear 365 will be forced to rotate at a speed greater than the rotational speed of crank gear 370. The only way this can happen is that, in addition to rotation, gear 365 also "travels" through crank gear 370. This will then create a torque applied to crank 325, causing the connecting rods to change their orientation relative to each other and causing the drive shaft to move along the defined path given by the Watt's connecting rod. In other words, this will cause drive shaft 372 to move or translate in a direction transverse to the axis of the drive shaft. Furthermore, as long as the speeds of the two motors differ, the connecting rods will continue to change orientation and the axis of the drive shaft will continue to move along the predefined path.

Assuming two motors operate at the same speed to produce pure rotational movement of the drive shaft, the position of the drive shaft can be changed from one point to another by altering the phase relationship between the two motors. The speed at which the phase change occurs determines the speed at which the drive shaft translates to its new position, as determined by the Watt's linkage.

In the foregoing description, for simplicity, it is assumed that the pulleys are the same size and the gears are the same size and have the same ratio. However, this is not necessary. The pulleys can be different sizes, and the gears can be different sizes. In any case, the key operating condition for achieving pure rotational movement is that both gears 365 and 360 cause the crank gear 370 to rotate at the same speed. Then, any speed change of one motor or the other will cause a translational movement of the drive shaft 372. In other words, any phase displacement of either motor 340 or motor 345 will cause a corresponding translational movement of the drive shaft 372.

If the configuration shown in Figure 3 is used as a drivetrain for the vehicle's wheels, motors 340 and 345 will be attached, for example, to the vehicle's frame or chassis, and the wheel rims and tires will be attached to driveshaft 372. This arrangement, because it allows for two degrees of freedom, can be used to propel the vehicle and actively control the height of the chassis above the road surface (this capability can be used to provide active damping functionality).

Another embodiment of the multi-link drive system combines the two motors of Figure 3 into a single motor, wherein the axis of rotation is located at the center of the crank. Schematic representations of this other embodiment of the multi-link drive system are shown in Figures 5A and 5B.

The transmission system includes two rocker arms 515 and 520 and a crank assembly 534 connecting the corresponding ends of the two rocker arms 515 and 520. The crank assembly 534 includes a crankshaft 535c having two crank arms 535a and 535b, one at each end of the crankshaft 535c. Each crank arm extends laterally relative to the axis of rotation of the crankshaft 535c and is oriented 180° relative to each other. One end of the rocker arm 520 is pivotally connected to the crank arm 535a via a bearing, while the other end of the rocker arm 520 is pivotally connected to the mounting structure 570a via another bearing. Similarly, one end of the rocker arm 515 is pivotally connected to the crank arm 535b (not visible) via its own bearing, while the other end of the rocker arm 515 is pivotally connected to the mounting structure 570b via yet another bearing. This combination of components forms a four-bar arrangement similar to the one shown in Figure 3, and constrains the crankshaft's axis of rotation to follow a defined path as the orientation of the links changes.

The electric motor in the drive system comprises two stator assemblies 540 and 545 and a rotor assembly 530, each of which is mounted on a crankshaft 535c using bearings, allowing it to rotate independently of the other two components. The rotor assembly 530 includes a ring of bolts around its periphery for mounting a rim and tire (not shown) to the rotor assembly 530.

It should be noted that bearings are not shown in Figures 5A and 5B to simplify the figures. However, they are clearly shown in Figure 7, which will be discussed later. Additionally, as will be clearly shown in conjunction with Figure 7, the motor in the described embodiment is an electric axial flux motor, wherein the stator assembly is a coil stator assembly and the rotor assembly is a magnetic rotor assembly. Furthermore, it should be noted that the term "stator" may sometimes be understood to imply that the component referred to is fixed and does not rotate, but this is not intended to be so limited in the current context. The stator assembly described herein is capable of rotation about an axis of rotation, which may be the same as or different from the axis of rotation of the rotor assembly. This capability is an important feature because, at least in some embodiments, it enables the transmission system to have two degrees of freedom: rotation and translation.

Returning to Figures 5A and 5B, each swing arm 515 and 520 is mechanically connected to its corresponding stator assembly 540 and 545. Swing arm 520 has two airfoil extensions 536a and 536b. Torque links 539a and 539b connect airfoil extensions 536a and 536b to stator assembly 545, respectively. Similarly, on the other side of the drivetrain, swing arm 515 also has two airfoil extensions 537a and 537b (not visible in the figures). Torque links 538a and 538b connect airfoil extensions 537a and 537b to stator assembly 540, respectively. Torque links 539a and 539b are used to transmit torque generated by stator assembly 545 to swing arm 520, and torque links 538a and 538b are used to transmit torque generated by stator assembly 540 to swing arm 515.

Although each stator assemblies 540 and 545 are freely rotatable about the axis of crankshaft 535c by being mounted on the crankshaft with bearings, the torque linkages connecting them to the multi-link constrain this movement, preventing them from rotating freely without restriction. In effect, the torque linkages limit the rotation of the stator assemblies to a narrower range of permissible rotation. This limited range of rotation allows the drive signal to be connected to the coils in the stator assembly using a wiring harness, rather than requiring commutation or some other method to provide the drive signal to the coils on the stator assembly.

Note that in Figure 5A, there are four points labeled A, B, C, and D. These points define four distances: AB, AC, CD, and BD. AB represents the length of the torque link, CD represents the length of the crank arm, AC represents the radial distance between the axis of the crankshaft and the attachment point of the torque link to the stator assembly, and BD represents the distance between the point where the crank arm connects to the rocker arm and the point where the torque link connects to the extension of the rocker arm. In the described embodiment, these lengths are designed to have the following relationship with each other: AB = CD and AC = BD. This defines a parallelogram. As a result of this arrangement, rotation of the stator assembly relative to the vertical line translates into a corresponding and identical rotation of the rocker arm about its attachment point to the mounting structure in the same direction. In other words, if the stator assembly 545 rotates clockwise, this will push the rocker arm 520 upward, which also corresponds to the clockwise rotation of the rocker arm 520 about the mounting structure 570a.

The multi-link drive systems of Figures 5A and 5B operate in a manner similar to that of the embodiment shown in Figure 3. Pure rotational motion of the rotor assembly 530 is produced when drive signals are applied to each of stator assemblies 540 and 545 such that both drive signals produce the same torque and cause the rotor assembly 530 to rotate clockwise. (Note: The direction of rotation is viewed from the motor side, in this case, the side where the stator assembly 545 is located. This will be the convention used throughout the rest of the description.) The orientation of the rocker arms 515 and 520 will remain fixed, and the crankshaft 535c will not move laterally. This is because the torque applied to the crankshaft 535c by the stator assembly 540 is canceled out by the torque applied to the crankshaft 535c by the stator assembly 545. Torques of equal magnitude but opposite direction on the links do not produce a net torque on either link.

On the other hand, if the drive signal on one stator assembly changes relative to the other drive signals, a net torque will exist on the crank assembly, causing it to change its orientation/position. Therefore, as it rotates, the crankshaft will also move along the path defined by the multi-link.

To understand how a multi-link drive system can operate to translate the crankshaft, consider this scenario: the magnetic rotor assembly is prevented from rotating for some reason, and the rocker arms are moved. This can be visualized with the aid of Figures 6A to 6F, which show the various relative positions of the drive system components as the crankshaft 535c and rotor assembly 530 (on which the wheels will be mounted) move (or translate) from an upper position (Figure 6A) to a lower position (Figure 6F). The downward-pointing arrows in each figure indicate the direction of movement of the rotor assembly and crank assembly. As the rotor assembly 540 moves downward from the position depicted in Figure 6A, the crank assembly and rocker arms 515 and 520 will move downward with it. Simultaneously, torque links 538 and 539 will cause the stator assemblies 540 and 545 to rotate in the same direction as the rocker arms 515 and 520 rotate about their respective mounts 570a and 570b. The downward movement of the rocker arm 520 represents a counterclockwise rotation about its mount 570b. Therefore, the stator assembly 545 will be forced to rotate counterclockwise by the same amount about the crankshaft 535c. On the other side of the multi-link drive system, the downward movement of the rocker arm 515 represents a clockwise rotation about its mounting 570a. Therefore, the stator assembly 540 will be forced to rotate clockwise about the crankshaft 535c.

As indicated in Figures 6C-F, this relative movement of the components continues as the axis of the rotor assembly 530 moves further along the path defined by the multi-link relative to the axis of the crankshaft 535c. Note that the stator assemblies 540 and 545 depicted in the figures have reference slots, which should facilitate observation of the rotation of these components as the rotor assembly 530 moves toward its position below that indicated in Figure 6F. Also note the arrows indicating the direction of rotation of the stator assemblies.

It should be apparent that the movement depicted in Figures 6A-F can be generated by applying appropriate drive signals to stator assemblies 540 and 545. These drive signals need to apply a net torque of zero to rotor assembly 530, so that rotor assembly 530 does not rotate, while simultaneously driving stator assemblies 540 and 545 to rotate in opposite directions relative to each other. For example, if stator 545 applies torque (through electromagnetic force on rotor assembly 530) to rotate itself counterclockwise (and subsequently drive rotor assembly to rotate clockwise), it also applies a force to rocker arm 520 via torque links 539a and 539b that push rocker arm 520 upwards. There must then be a balancing force at crank assembly 534 pushing crank assembly 534 downwards (because at small accelerations, the sum of forces is zero). Crank assembly 534 then pushes rocker arm 520 downwards. Therefore, the rocker arm 520 has the force to push it down to its connection with the crank assembly 534 and to push it up to its connection with the torque connecting rods 539a and 539b. In effect, a rotational torque is applied to the rocker arm 520, causing it to begin rotating counterclockwise, i.e., in the same direction as the stator assembly 545. A similar action occurs on the other side of the rotor assembly 530 at the stator assembly 540 and the rocker arm 515.

If stator assemblies 540 and 545 rotate in a manner that causes the corresponding rocker arms 515 and 520 to rotate in the upward direction, then rocker arms 515 and 520 (and rotor assembly 530) move upward. If stator assemblies 540 and 545 rotate in a manner that causes rocker arms 515 and 520 to rotate in the downward direction, then rocker arms 515 and 520 (and rotor assembly 530) move downward. If one rocker arm rotates downward while the other rotates upward, and if the torques are balanced, then rocker arms 515 and 520 do not move.

In summary, to make rotor assembly 530 rotate without translation, the same torque is applied to stator assemblies 540 and 545 in the same direction. In this case, the torques applied to each rocker arm cancel each other out, and the rotor assembly rotates. To make rotor assembly 530 translate, the same but opposite torques are applied to stator assemblies 540 and 545. This causes rocker arms 515 and 520 to move in the same direction.

Because the multi-link drive system is a linear system, the rotation of the rotor assembly 530 and the translational movement of the crankshaft 535c (and the rotor assembly 530) can be achieved by adding separate signals required to generate each type of motion. In other words, by using appropriate drive signals, the rotor assembly can be rotated while simultaneously being translated vertically.

In the above discussion, inertial effects were ignored. When inertial effects are added, they change the magnitude of the required torque and force, but they do not change the general principles of how multi-link transmission systems operate. Furthermore, the above discussion explained that rotation occurs when torques are equal and of the same sign, and motion (or translation) occurs when torques are equal but of opposite signs. This holds true at some points, but not all, along the defined path of translation (see Figure 2). In general, at other locations, there is some minor "crosstalk" or "non-orthogonality."

Figure 7 shows an example of the structure of an electric drive motor 600 that can be used in the previously described embodiments. It comprises two coaxially arranged axial flux motors connected together along a common axis of rotation. In this case, they are mounted on a crank assembly 602, which corresponds to the crank assembly 534 discussed in conjunction with the multi-link drive system depicted in Figures 5A and 5B. The crank assembly 602 includes a crankshaft 603a having crank arms 603b and 603c located at opposite ends of the crankshaft 603a and oriented 180° relative to each other. In Figure 7, the two motors are identified as motor #1 and motor #2.

In general, each axial flux motor has a coil stator assembly sandwiched between two magnetic rotor assemblies 608. Each coil stator assembly is a disk rotatably mounted on a crankshaft 603a, with an array of coils 612 arranged around an annular region of the disk. Each magnetic rotor assembly 608 is also a disk rotatably mounted on the crankshaft 603a. Radially oriented strip permanent magnets 614 are mounted on each disk of each magnetic rotor assembly 608, the permanent magnets being distributed around an annular region of the disk. The array of magnets 614 on the magnetic rotor assembly 608 is aligned with the array of coils 612 on the coil stator assembly.

The magnetic rotor assemblies 608 of two coaxially aligned motors are rigidly attached to a common hub assembly 616, which is then mounted on a bearing 618 located between the hub assembly 616 and the crankshaft 603a. Thus, the plurality of magnetic rotor assemblies 608 can rotate freely together as a single unit around the crankshaft 603a.

The disc of the coil stator assembly sandwiched between the magnetic rotor assemblies 608 has a circular central opening 620 through which the hub assembly 616 passes without contacting the disc. Therefore, the coil stator assemblies and the hub assembly 616 can rotate independently of each other. Each coil stator assembly is supported around its periphery by a housing 622, which is then rotatably mounted on and supported on a crankshaft 603a by a set of bearings 624. The bearings 624 allow the housing 622 and the coil stator assemblies it supports to rotate freely on the crankshaft 603a, just as the magnetic rotor assemblies 608 can. Although the magnetic stator assemblies 608 all rotate on the crankshaft 603a as a single unit, each coil stator assembly rotates on the crankshaft 603a independently of the other coil stator assembly and independently of the hub assembly 616.

The magnets within the two arrays of permanent magnets are arranged relative to each other, thereby generating axially oriented magnetic fields that are reversed at regular intervals as one magnet moves around a ring-shaped region of the disk. These axially oriented magnetic fields generated by the magnet arrays intersect the radially oriented windings of coil 612 on coil assembly 608. When current flows through the coil windings, the interaction between the current and the magnetic fields generates a Lorentz force on the magnetic rotor assembly 608 and the coil stator assembly. This tangentially oriented force applies a torque to the disk to rotate it, wherein the disk of the magnetic rotor assembly 608 is propelled to rotate about crankshaft 603a in one direction, while the disk of the coil stator assembly is propelled to rotate about crankshaft 603a in the opposite direction.

When the electric drive motor is coupled to the connecting rod arrangement as previously described, the magnetic rotor assembly rotates freely about the crankshaft; however, each coil stator assembly is restricted by the connecting rod to operate only within a limited range of rotation. The magnetic rotor assembly 608 is primarily used to apply torque to the wheel to which it is connected; while the coil stator assembly is primarily used to apply torque to the connecting rod, thereby changing their orientation relative to each other, as previously described.

Figures 8 through 12B illustrate embodiments of incorporating a multi-link drive system into, for example, a wheel in a vehicle. The vehicle wheel assembly 800 includes a tire 804 mounted on a rim 806. A biaxial flux motor is housed within the space enclosed by the rim 806 and coupled to a multi-link system 801, which is similar in design to those already described.

Referring also to Figure 10, the multi-link system 801 includes a support structure 807, which is attached to the vehicle's suspension via a coupling 809. At one end of the support structure 807, there is a swing arm 815 attached to the support structure 807 via a spring load bearing mechanism 816. At the other end of the support structure 807, there is a swing arm 820 attached to the support structure via another spring load bearing mechanism 817.

Without the springs in the spring-loaded bearing assemblies 816 and 817, the drivetrain would be physically positioned such that, when no power is applied to the drivetrain, the chassis or vehicle to which the drivetrain is attached is closest to the ground (i.e., the swing arms 815 and 820 would be in their highest position). The springs in the spring-loaded bearing assemblies 816 and 817 would keep the drivetrain in a neutral or normal position without requiring a continuous power supply to the drive motor to perform the aforementioned task.

The ends of each rocker arm 815 and 820, opposite to bearing structures 817 and 816 respectively, are rotatably connected to crank assembly 834. Crank assembly 834 consists of crankshaft 803a with two crank arms 803b and 803c, one crank arm at each end. Crankshaft 803a supports two sets of bearings 818 and 824. Bearing 818 rotatably supports hub assembly 810 (see Figures 11A and 11B) on which magnetic rotor assembly 812 is mounted, and bearing 824 rotatably supports housing 822 (see Figures 8 and 9) which holds coil stator assembly 814 between magnetic rotor assemblies 812. Bearing 818 allows hub assembly 810 to which all magnetic rotor assemblies 812 are attached to to rotate about crankshaft 803a. The bearing 824 enables the supporting housing 822, together with its corresponding coil stator assembly 814, to rotate about the crankshaft 803a and independently of each other. Each housing 822 has a cover 842 through which cables pass to connect to and supply drive signals to the supported coil stator assembly 814.

Each magnetic rotor assembly 812 consists of two disks 813 mechanically connected together. Each disk 813 holds an array of permanent magnets 826 arranged around an annular region of the disk 813. The magnetic moments of the permanent magnets are axially aligned and periodically reversed as the permanent magnets move around the outer periphery of the rotor assembly. The magnets 826 on one disk 813 are aligned with the magnets 826 on the other disk within the pair of disks, and their magnetic moments point in the same direction to enhance the field experienced by the coils in the coil stator assembly.

Referring again to Figures 11A and 11B, the hub assembly 810 consists of three parts: a rim support disc 809, which is sandwiched between a pair of rotor support assemblies 819 and fastened together by a ring of bolts 821. Each rotor support assembly 819 supports a pair of magnetic rotor assemblies 812. A coil stator assembly 814 (see Figures 12A and 12B) is positioned between each pair of magnetic rotor assemblies 812. The hub assembly 810 defines a bore 811 through which the crankshaft 803a, along with bearings 818 and 824, passes.

Each rocker arm 815 and 820 includes an airfoil extension 830 bolted to the end of the rocker arm connected to the crankshaft assembly 834. The airfoil extension 830 provides two points at which a torque link 832 is connected to the rocker arm. The other end of the torque link is connected to the housing 822. As explained earlier, the torque link 832 provides a way to transmit the torque generated by the coil stator assembly 814 to the rocker arms 815 and 820.

Figure 13 is a schematic diagram of a vehicle 900, which includes, for example, four multi-link drivetrains 920 mounted on a passenger body or chassis 910 as previously described. In this example, each drivetrain 920 occupies space that would normally be occupied by a typical wheel assembly. Although this particular example is characterized by having four multi-link drivetrains 920, it could have only two such drivetrains in the front or rear. Furthermore, other types of vehicles utilizing multi-link drivetrains are conceivable. For example, vehicles with one, two, three, or more wheels are conceivable, in which multi-link drivetrains are used to implement one or more of the wheels.

Figure 14 illustrates another embodiment of the integrated wheel and suspension assembly 1010, which, for a vehicle on which the wheel and suspension assembly 1010 is mounted, enables rotational movement of the tires 1012 to propel the vehicle forward and translational (i.e., vertical) movement of the tires to provide a portion of active suspension. It includes an axial flux motor assembly 1100 supported by suspension forks having two suspension arms 1020a and 1020b, wherein the motor assembly 1100 is slidably mounted so that it can slide vertically under the control of the motor assembly. A pair of crescent-shaped links 1030a and 1030b, of which only one is visible in Figure 14, physically connect the rotatable portion of the motor assembly to anchor points on the suspension arms 1020a and 1020b. A connecting bracket 1036, located near the upper end of the suspension arms 1020a and 1020b, clamps onto each of the arms 1020a and 1020b and rigidly holds them in a fixed position relative to each other.

Referring to Figure 15, the motor assembly 1100 includes two coil stator assemblies 1102a and 1102b, and a magnetic rotor assembly consisting of three magnetic rotors, including outer magnetic rotors 1104a and 1104b and a central magnetic rotor 1104c. One coil stator assembly 1102a is sandwiched between and spaced apart from the magnetic rotors 1104a and 1104c, and the other coil stator assembly 1102b is sandwiched between and spaced apart from the magnetic rotors 1104c and 1104b. Each of the outer magnetic rotors 1104a and 1104b is a generally annular structure arranged along the hub assembly or the central cylindrical main shaft 1106, and its axis is aligned with the axis of the main shaft 1106. The central magnetic rotor 1104c is mounted on the main shaft 1106 via a bearing assembly 1108, allowing it to rotate freely about a rotation axis 1107, which is defined by the axis of the main shaft 1106. Around the central magnetic rotor 1104c, two other magnetic rotors 1104a and 1104b are attached to cylindrical collars 1110, with one magnetic rotor 1104a on one side of the collar 1110 and the other magnetic rotor 1104b on the other side. In this arrangement, the two outer magnetic rotors 1104a and 1104b rotate with the central magnetic rotor 1104c about the rotation axis and the main shaft 1106.

Each of the generally disc-shaped coil stator assemblies 1102a and 1102b is also mounted on the main shaft 1106 via bearing assemblies 1109a and 1109b, respectively, so that they can also rotate independently of each other and independently of the magnetic rotor assembly about a rotation axis defined by the axis of the main shaft 1106. Each coil stator assembly 1102a and 1102b has an annular region, and within said annular region, there is an array of coils 1114 distributed around the disc. As shown in Figures 14 and 15, there is also a connector 1116 for electrical connection to the coils within the coil array, and drive signals are delivered to those coils through said connector. The coils are manufactured or wound to create generally radially oriented current paths through which drive current is transmitted to operate the motor.

Each of the outer magnetic rotors 1104a and 1104c is annular and has an annular region 1118, while the central magnetic rotor 1104c is disc-shaped and has an annular region 1120. When the three magnetic rotors are mounted on the main shaft 1106, these annular regions 1118 and 1120 are generally aligned with the annular regions of the coil stator assemblies 1102a and 1102b. Around each magnetic rotor and within the annular regions, there is an array of permanent magnets 1122. As will be described in more detail later, the magnets 1122 are arranged to generate an axially oriented magnetic field that intersects with the coil windings of the coil stator assembly and alternates from one axial direction to the opposite axial direction as one magnet moves around the rotor.

The described embodiment also includes a spoke assembly 1124 that surrounds the collar 1110 and extends out to support a rim 1126 to which a tire (not shown) can be mounted. The spoke assembly is used instead of a solid material ring as a weight-saving measure. A brake disc 1128 is also attached to the spoke assembly 1124, and a brake caliper 1129 is mounted on the suspension arm 1020b.

The motor assembly can be considered as two coaxially arranged axial flux motors connected together along a common axis of rotation. This is indicated in Figure 15 as motor #1 on the left and #2 on the right. Motor #1 is represented by a coil stator assembly 1102a sandwiched between the left half of magnetic rotor 1104a and magnetic rotor 1104c, and motor #2 is represented by a coil stator assembly 1102b sandwiched between the right half of magnetic rotor 1104c and magnetic rotor 1104b. In this case, the magnetic rotors are all connected together so that they rotate together.

Referring now to Figures 16, 17, 18A, and 18B, we will describe how the motor assembly 1100 is integrated into the integrated wheel and suspension assembly 1010 and how the entire system operates to produce rotational and translational motion.

Two linear bearings 1140a and 1140b are located at the ends of the main shaft 1106, respectively held within hollow regions inside suspension arms 1020a and 1020b. The linear bearings 1140a and 1140b can slide vertically within their respective suspension arms 1020a and 1020b, thereby allowing the main shaft 1106 to also move vertically. The linear bearing 1140b of the described embodiment is shown in more detail in FIG. 22. It comprises two blocks 1150a and 1150b fixed within a hollow space inside arm 1020b. A cylindrical guide 1152 is located between and rigidly connected to the two blocks 1150a and 1150b. A collar bearing 1154 surrounds the guide 1152 and is capable of vertical movement on the guide 1152. The main shaft 1106, supporting the motor and wheels, is connected to the collar bearing 1154.

Returning to Figures 18A and 18B, the crescent-shaped link 1030a connects between a fixed position on the suspension arm 1020a and the coil stator assembly 1102a. It is connected to the suspension arm 1020a via a bearing mount 1142a and to the coil stator assembly 1102a via another bearing mount 1144a. Similarly, the crescent-shaped link 1030b connects between a fixed position on the suspension arm 1020b and the coil stator assembly 1102b. It is connected to the suspension arm 1020b via a bearing mount 1142b and to the coil stator assembly 1102b via another bearing mount 1144b.

The crescent-shaped link is attached to the suspension arm and the coil stator assembly such that there is rotational symmetry between them about a vertical axis 1146 that intersects the axis of the main shaft 1106. That is, if the wheel and the suspension assembly 1010 are rotated 180° about said axis 1146, the position of the link and its attachment point will appear the same.

Note that the linkage causes the wheel to move in the following manner. If the coil stator assembly 1102b rotates clockwise by a certain amount, as shown in Figure 18A, this will have two results. This will push the main shaft 1106 and bearings 1140a and 1140b downwards within the suspension arms 1020a and 1020b. And this will cause the coil stator assembly 1102a to rotate counterclockwise by the same amount. The resulting configuration will be shown in Figure 18B.

This relates to the system's operation when drive currents are applied to coil stator assemblies 1102a and 1102b. First, assume that drive currents are applied to coil stator assembly 1102a to generate torques that cause coil stator assembly 1102a to rotate counterclockwise (as indicated by the arrow labeled A) and that cause the magnetic rotor assembly (plus wheels) to rotate clockwise. Also assume that drive currents are applied to coil stator assembly 1102b to generate torques that cause coil stator assembly 1102b to rotate clockwise (as indicated by the arrow labeled B) and that cause the magnetic rotor assembly (plus wheels) to rotate counterclockwise. If the magnitudes of the torques generated by the drive currents applied to coil stator assemblies 1102a and 1102b are equal, then the torque generated by coil stator assembly 1102a on the magnetic rotor assembly will be completely canceled out by the torque generated by coil stator assembly 1102b on the magnetic rotor assembly. Therefore, the magnetic rotor assembly will experience zero net torque, and it, along with the attached wheel, will not rotate but will remain stationary. However, the coil stator assemblies 1102a and 1102b will rotate in opposite directions as indicated by the arrows. This will push the main shaft 1106 downwards or conversely, and the attached tire, via connecting rods 1030a and 1030b; which will push the vehicle to which the suspension arms are attached, upwards.

Consider another operating mode, which will be described with reference to Figure 19. In this case, assume that the drive currents applied to the coil stator assemblies 1102a and 1102b cause them to rotate in the same direction. More specifically, the drive current applied to the coil stator assembly 1102a causes the magnetic rotor assembly to rotate clockwise, while also causing the coil stator assembly 1102a to rotate counterclockwise (as indicated by the arrow marked with the letter E). Furthermore, the drive current applied to the coil stator assembly 1102b causes the magnetic rotor assembly to rotate clockwise, and simultaneously causes the coil stator assembly 1102b to rotate counterclockwise (as indicated by the arrow marked with the letter E). Link 1030a transmits the torque applied by the coil stator assembly 1102a to the main shaft 1106, thereby pushing it downwards; while link 1030b transmits the torque applied by the coil stator assembly 1102b to the main shaft 1106, thereby pushing it upwards. Assuming that the drive currents applied to the coil stator assemblies 1102a and 1102b are chosen to produce the same amount of torque, the forces applied to the main shaft 1106 will completely cancel each other out, and the main shaft 1106 will remain fixed (i.e., it will neither move upwards nor downwards). On the other hand, since both the coil stator assemblies 1102a and 1102b cause the magnetic rotor assembly to rotate in the same direction, the wheel will rotate in that direction.

In summary, there are two operating modes: one referred to as common-mode operation and the other as differential-mode operation. In common-mode, the drive signals applied to both coil stator assemblies produce equal torques of the same sign on the magnetic rotor assembly. During pure common-mode operation, the wheels rotate, but there is no translational (vertical) movement. In differential-mode, the drive signals applied to both coil stator assemblies produce equal torques of opposite signs on the magnetic rotor assembly. During pure differential-mode operation, the wheels do not rotate, but there is translational (vertical) movement. By appropriately selecting the drive current to the coil stator assemblies, a combination of both types of movement can be generated simultaneously.

Conceptually, the linkage system just described can be viewed as two mechanical systems operating together to produce translational movement of the wheel. One system consists of suspension forks and internal linear bearings that constrain the main shaft to move along a predefined path, which in this case is a linear path. The other system consists of a linkage arrangement that converts the relative rotational movement of two coil stator assemblies relative to each other into translational movement of the main shaft (or rotating element) along a predefined path defined by the suspension forks. It should be noted that in the illustrated embodiment, the linkage arrangement corresponds to a four-bar linkage.

Figures 20A and 20B illustrate the two mechanical systems. A linear bearing 1140b inside arm 1020b constrains the axis of spindle 1106 to move up and down along a linear path defined by guides within the linear bearing. The linkage arrangement for moving the spindle along this path in response to torque generated by an electric motor is a multi-link mechanism comprising four links or linkages 1180a, 1180b, 1182a, and 1182b. Two of the four linkages are represented by elements that connect the coil stator assembly to fixed positions on the suspension arm. On one side, a linkage 1180b exists between a point on the coil stator assembly 1102b located at a fixed distance from the axis of rotation of the coil stator assembly 1102b (represented by bearing mount 1144b) and an anchor point 1142b on arm 1020b. On the other side (partially obscured in the side view shown in the figure), a link 1180a exists between a point on the coil stator assembly 1102a located at a fixed distance from the axis of rotation of the coil stator assembly 1102a (indicated by bearing mount 1144a) and an anchor point 1142a on the arm 1020a. The remaining two links 1182a and 1182b are represented by the connection between the spindle 1106 and the bearing mounts 1144b and 1144a on the coil stator assemblies 1102b and 1102a, respectively. In Figures 20A and 20B, these two links are represented by elements 1182b and 1182a. It should be noted that the four links effectively connect their ends together at hinge points. The coil stator assemblies 1102a and 1102b reconfigure the links by altering the physical arrangement of the four links by applying appropriate torque to the links 1182a and 1182b, thereby causing them to rotate. The reconfiguration of the connecting rods forces the spindle to move along a linear path defined by the linear bearings.

Figure 23 depicts a vehicle 1200 comprising four electric motor drive systems 1202, one of which drives one of the four wheels (only two drive systems are shown in the side view). Each electric motor drive system 1202 occupies space typically occupied by a wheel and suspension assembly and is attached to the vehicle's frame or body. Although the described embodiment includes four drive systems 1202, one for each wheel, the vehicle may use the drive systems only on the front wheels (or rear wheels). Other embodiments include one-wheeled, two-wheeled, and three-wheeled vehicles or personal transport systems in which one or more wheels are driven by the electric motor drive systems described herein.

In the above embodiment, the link has a crescent shape and is anchored to points on the suspension arms aligned with each other. However, the shape of the link and its anchor points are not particularly important. In the described embodiment, the crescent shape is chosen to meet certain physical constraints imposed by the design shown. Other shapes and/or arrangements are of course possible. For example, referring to FIG. 21, straight links 1160a and 1160b are used, and each link is anchored to bosses 1162a and 1162b extending from the suspension fork members, respectively.

It should be noted that in the described embodiment, each coil stator assembly is connected to an anchor point on the support structure (i.e., the suspension arm) via a corresponding link, and the axle is constrained to move only along a path defined by a linear bearing sliding within the suspension arm. The linear bearing is a specific example of a sliding mechanism, but other embodiments of it may also be used. Besides sliding mechanisms, other methods exist to constrain the movement of the axle along a predefined lateral path. For example, a simple swing arm or swing arm arrangement may be used between the vehicle frame and the axle. In this case, the vertical movement of the wheel does not follow a strictly linear path, but rather the path will be curved, having a radius defined by the length of the swing arm.

Figures 25A-C illustrate an example of an embodiment using a swing arm 1194 to define a path on which the axle 1106 can move, the path being an arc whose radius is determined by the lengths of the swing arms 1194a and 1194b (which are visually obscured by the swing arm 1194a in the figures). Block 1188 represents a support to which the vehicle frame or drivetrain is connected. The linkage arrangement for moving the main shaft 1106 along the path in response to torque generated by the electric motor is a multi-link mechanism comprising four links or linkages 1190a, 1190b, 1192a, and 1192b. Two of the four linkages are represented by elements that connect the coil stator assembly to a fixed position on the frame 1188. On one side, a linkage 1190b exists between a point on the coil stator assembly 1102b located at a fixed distance from the axis of rotation of the coil stator assembly 1102b (represented by bearing mount 1194b) and an anchor point 1196b on the frame 1188. On the other side of the motor (partially hidden in the side view shown in the figure), there is a connecting rod 1190a between a point on the coil stator assembly 1102a located at a fixed distance from the axis of rotation of the coil stator assembly 1102a (indicated by bearing mount 1194a) and an anchor point 1196a on the frame 1188. (Note that the two anchor points 1196a and 1196b on the frame 1188 are collinear and equidistant from the main shaft 1106.) The remaining two connecting rods are indicated by the connection between the main shaft 1106 and the bearing mounts 1196b and 1196a on the coil stator assemblies 1102b and 1102a, respectively. In Figures 25A-C, these two connecting rods are indicated by elements 1192b and 1192a. It should be noted that the four connecting rods effectively connect their ends together at the hinge point. The coil stator assemblies 1102a and 1102b rotate by altering the physical arrangement of the four links by applying appropriate torque to the links 1192a and 1192b, thereby reconfiguring the links. The reconfiguration of the links forces the spindle to move along a flexural path defined by the rocker arms 1194a and 1194b.

In the sequence shown in Figures 25A-C, when the coil stator assembly 1102b rotates clockwise (as indicated by the solid curved arrow) and the coil stator assembly 1102a rotates counterclockwise (as indicated by the dashed curved arrow), the distance between the main shaft 1106 and the anchor points of the connecting rods 1190a and 1190b increases, pushing the wheel downwards. The rotation of the coil stator assembly in the opposite direction pulls the wheel upwards.

Other well-known methods are also possible. There are also usable multi-link systems, examples of which are well known to those skilled in the art.

Furthermore, it should be understood from the above description that the use of the term "stator," for example in the case of the coil stator assembly, does not imply that the component is fixed and cannot rotate or move. Typically, the term can be given this rather limited meaning, but it is not used in this context. It should be understood from the above description that the coil stator assembly also rotates about the rotational axis of the motor assembly.

It should be understood that the bearing arrangement used in the described embodiments is merely one of many alternatives that can be used, allowing the two coil stator assemblies and the magnetic rotor assembly to rotate independently of each other about their axis of rotation. They do not all need to use the spindle as one of the bearing surfaces. Figure 24 shows an alternative arrangement in which bearings 1209a and 1209b rotatably mount the coil stator assembly onto the magnetic rotor assembly. Additionally, the hub assembly is represented by the spindle 1106, but it could be another arrangement supporting the two motors along their axes of rotation.

While the described embodiments specifically relate to providing active suspension for a vehicle using a second degree of freedom obtainable from the drivetrain, this second degree of freedom may be used for other purposes depending on the application in which the drivetrain is used. For example, the drivetrain may be used as an electric motor in an aircraft or other aircraft, in which case the second degree of freedom may be used to, for example, control blade spacing. If the drivetrain is used in machinery, the second degree of freedom may be used for other purposes requiring linear or translational movement of components.

Other embodiments are within the scope of the claims. For example, although a particular four-bar linkage, i.e., the Watt's linkage, has been described, many other multi-bar arrangements exhibiting similar behavior and usable in place of the Watt's linkage exist. Without being intended to be limiting, other examples include multi-bar linkages with a number of connecting rods other than four, Chebyshev linkages, and Peaucellier-Lipkin linkages. Additionally, motors other than axial flux motors can be used, including other types of motors such as those having a magnetic rotor and coil stator assembly, or a coil rotor and magnetic stator assembly, or motors based on alternating reluctance technology, or commutators, or single-phase or multi-phase drives, or DC drives, etc.

Although exemplary embodiments have been specifically shown and described, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the embodiments covered by the appended claims.

Claims (40)

1. An electric drive system, the electric drive system comprising: A magnetic rotor assembly that is rotatable about a rotation axis; A first coil stator assembly, coaxially aligned with and rotatable about the rotation axis, is configured to receive a first drive signal and, in response to the first drive signal, apply a first torque to the magnetic rotor assembly; and A second coil stator assembly, coaxially aligned with and rotatable about the rotation axis, is configured to receive a second drive signal and, in response to the second drive signal, apply a second torque to the magnetic rotor assembly. The second coil stator assembly is mechanically coupled to the first coil stator assembly such that motion of the first coil stator assembly is coupled to motion of the second coil stator assembly. When the first torque and the second torque are simultaneously applied to the magnetic rotor assembly, the first torque and the second torque cause at least one of the following: The magnetic rotor assembly rotates around the rotation axis; or At least the magnetic rotor assembly, the first coil stator assembly, and the second coil stator assembly move along a defined path in a lateral direction relative to the axis of rotation. 2. The electric drive system according to claim 1, wherein when the first torque and the second torque are substantially equal in magnitude and applied to the magnetic rotor assembly in the same direction, the first torque and the second torque primarily cause the magnetic rotor assembly to rotate. 3. The electric drive system according to claim 1, wherein when the first torque and the second torque are substantially equal in magnitude and applied in opposite directions to the magnetic rotor assembly, the first torque and the second torque primarily cause at least the magnetic rotor assembly, the first coil stator assembly and the second coil stator assembly to move along the defined path. 4. The electric drive system according to claim 1, wherein when the magnitudes of the first torque and the second torque are different, the first torque and the second torque cause the magnetic rotor assembly to rotate and cause at least the magnetic rotor assembly, the first coil stator assembly and the second coil stator assembly to move along the defined path. 5. The electric drive system according to claim 1, wherein the defined path is a linear path. 6. The electric drive system according to claim 1, wherein the defined path is a curved path. 7. The electric drive system according to claim 1, further comprising: A transmission device for coupling the motion of the first coil stator assembly to the motion of the second coil stator assembly. 8. The electric drive system according to claim 7, wherein The transmission device limits the respective rotational range of the first coil stator assembly and the second coil stator assembly; and The electric drive system also includes: A wiring harness communicatively connected to the first coil stator assembly and the second coil stator assembly, for sending the first drive signal to the first coil stator assembly and the second drive signal to the second coil stator assembly. 9. The electric drive system according to claim 7, wherein... In response to the first torque being applied to the magnetic rotor assembly, the first coil stator assembly is subjected to a first reaction torque; In response to the second torque being applied to the magnetic rotor assembly, the second coil stator assembly is subjected to a second reaction torque; and The electric drive system also includes: A first torque link, connecting the first coil stator assembly and the transmission device, to transmit the first reaction torque from the first coil stator assembly to the transmission device; and A second torque link, which connects the second coil stator assembly and the transmission device, transmits the second reaction torque from the second coil stator assembly to the transmission device. 10. The electric drive system according to claim 1, further comprising: A support structure, wherein the support structure is connected to the first coil stator assembly and the second coil stator assembly, The support structure is configured to be attached to the suspension of a vehicle. 11. The electric drive system according to claim 10, further comprising: An actuator operatively coupled to the support structure to apply a preload to at least one of the first coil stator assembly or the second coil stator assembly, the preload being configured to increase the height of the vehicle's chassis coupled to the support structure. 12. The electric drive system of claim 11, wherein the actuator comprises a spring. 13. A vehicle, said vehicle comprising: Chassis; and A plurality of wheel assemblies, at least one of which includes the electric drive system according to claim 0. 14. An electric drive system, the electric drive system comprising: A magnetic rotor assembly that is rotatable about a rotation axis; A first coil stator assembly, coaxially aligned with and rotatable about the rotation axis, is configured to receive a first drive signal and, in response to the first drive signal, apply a first torque to the magnetic rotor assembly; and A second coil stator assembly, coaxially aligned with and rotatable about the rotation axis, is configured to receive a second drive signal and, in response to the second drive signal, apply a second torque to the magnetic rotor assembly. A first torque link, rotatably connected to the first coil stator assembly; A second torque link, rotatably connected to the second coil stator assembly; and A component rotatably connected to the first torque link and the second torque link, the component being parallel to the axis of rotation. When the first torque and the second torque are simultaneously applied to the magnetic rotor assembly, the first torque and the second torque cause at least one of the following: The magnetic rotor assembly rotates around the rotation axis; or At least the magnetic rotor assembly, the first coil stator assembly, and the second coil stator assembly move along a defined path in a lateral direction relative to the axis of rotation. 15. The electric drive system according to claim 14, wherein When the first torque and the second torque are substantially equal in magnitude and applied to the magnetic rotor assembly in the same direction, the first torque and the second torque primarily cause the magnetic rotor assembly to rotate. When the first torque and the second torque are substantially equal in magnitude and applied in opposite directions to the magnetic rotor assembly, the first torque and the second torque primarily cause at least the magnetic rotor assembly, the first coil stator assembly, and the second coil stator assembly to move along the defined path; and When the magnitudes of the first torque and the second torque are different, the first torque and the second torque cause the magnetic rotor assembly to rotate and cause at least the magnetic rotor assembly, the first coil stator assembly and the second coil stator assembly to move along the defined path. 16. The electric drive system according to claim 14, wherein The first torque link, the second torque link, and the component limit the respective rotational range of the first coil stator assembly and the second coil stator assembly; and The electric drive system also includes: A wiring harness communicatively connected to the first coil stator assembly and the second coil stator assembly to send the first drive signal to the first coil stator assembly and the second drive signal to the second coil stator assembly. 17. A vehicle, the vehicle comprising: Chassis; Multiple wheel assemblies, at least one of which is connected to the chassis via a suspension and includes an electric drive system, each of the electric drive systems comprising: A magnetic rotor assembly that is rotatable about a rotation axis; A first coil stator assembly, which is coaxially aligned with and rotatable about the rotation axis, is configured to receive a first drive signal and apply a first torque to the magnetic rotor assembly in response to the first drive signal. A second coil stator assembly, coaxially aligned with and rotatable about the rotation axis, is configured to receive a second drive signal and apply a second torque to the magnetic rotor assembly in response to the second drive signal. The second coil stator assembly is mechanically coupled to the first coil stator assembly such that the motion of the first coil stator assembly is coupled to the motion of the second coil stator assembly. A support structure, the support structure being connected to the suspension, the first coil stator assembly, and the second coil stator assembly; and An actuator operatively coupled to the support structure to apply a preload to at least one of the first coil stator assembly or the second coil stator assembly, the preload being configured to increase the height of the chassis. When the first torque and the second torque are simultaneously applied to the magnetic rotor assembly, the first torque and the second torque cause at least one of the following: The magnetic rotor assembly rotates around the rotation axis; or At least the magnetic rotor assembly, the first coil stator assembly, and the second coil stator assembly move along a defined path in a lateral direction relative to the axis of rotation. 18. The vehicle according to claim 17, wherein: When the first torque and the second torque are substantially equal in magnitude and applied to the magnetic rotor assembly in the same direction, the first torque and the second torque primarily cause the magnetic rotor assembly to rotate. When the first torque and the second torque are substantially equal in magnitude and applied in opposite directions to the magnetic rotor assembly, the first torque and the second torque primarily cause at least the magnetic rotor assembly, the first coil stator assembly, and the second coil stator assembly to move along the defined path; and When the magnitudes of the first torque and the second torque are different, the first torque and the second torque cause the magnetic rotor assembly to rotate and cause at least the magnetic rotor assembly, the first coil stator assembly and the second coil stator assembly to move along the defined path. 19. The vehicle according to claim 17, wherein In response to the first torque being applied to the magnetic rotor assembly, the first coil stator assembly is subjected to a first reaction torque; In response to the second torque being applied to the magnetic rotor assembly, the second coil stator assembly is subjected to a second reaction torque; and The electric drive system also includes: A transmission device that couples the motion of the first coil stator assembly to the motion of the second coil stator assembly; A first torque link, connecting the first coil stator assembly and the transmission device, to transmit the first reaction torque from the first coil stator assembly to the transmission device; and A second torque link, which connects the second coil stator assembly and the transmission device, transmits the second reaction torque from the second coil stator assembly to the transmission device. 20. The vehicle of claim 17, wherein each of the plurality of wheel assemblies includes the electric drive system. 21. An electric motor, the electric motor comprising: A hub assembly that is rotatable about a rotation axis; A magnetic rotor assembly, which is rigidly attached to the hub assembly; First coil stator assembly; Second coil stator assembly; and A rotor bearing system rotatably supports each of the first coil stator assembly and the second coil stator assembly on the hub assembly such that each of the first coil stator assembly and the second coil stator assembly is rotatable about the rotation axis, the first coil stator assembly being rotatably coupled to the second coil stator assembly such that the motion of the first coil stator assembly is coupled to the motion of the second coil stator assembly. 22. The electric motor according to claim 21, further comprising: A transmission device for coupling the motion of the first coil stator assembly to the motion of the second coil stator assembly. 23. The electric motor according to claim 22, wherein In response to the application of a first torque to the magnetic rotor assembly, the first coil stator assembly is subjected to a first reaction torque; In response to the application of a second torque to the magnetic rotor assembly, the second coil stator assembly is subjected to a second reaction torque; and The electric motor also includes: A first torque link, connecting the first coil stator assembly and the transmission device, to transmit the first reaction torque from the first coil stator assembly to the transmission device; and A second torque link, which connects the second coil stator assembly and the transmission device, transmits the second reaction torque from the second coil stator assembly to the transmission device. 24. The electric motor according to claim 21, further comprising: A support structure, movably connected to the first coil stator assembly and the second coil stator assembly; and An actuator operatively coupled to the support structure to apply a preload to at least one of the first or second coil stator assembly, the preload increasing the height of the chassis coupled to the support structure. The support structure is configured to be attached to the suspension of a vehicle. 25. A transmission system for a vehicle, the transmission system comprising: A support structure, the support structure being connected to the vehicle's suspension; Rotary motor, the rotary motor comprising: A magnetic rotor assembly that rotates about a rotation axis; A first coil stator assembly, the first coil stator assembly being concentric with the rotation axis; and A second coil stator assembly, the second coil stator assembly being concentric with the rotation axis; and A transmission device is connected to the support structure and connects the first coil stator assembly to the second coil stator assembly, such that movement of the first coil stator assembly causes movement of the second coil stator assembly. 26. The transmission system according to claim 25, wherein the transmission device comprises: A first swing arm, one end of which is rotatably connected to the first coil stator assembly and the other end of which is rotatably connected to the support structure; and A second swing arm, one end of which is rotatably connected to the second coil stator assembly and the other end of which is rotatably connected to the support structure. 27. The transmission system of claim 26, wherein the first swing arm is coupled to the support structure via a bearing structure that prevents the other end of the first swing arm from translating relative to the support structure. 28. The transmission system according to claim 25, wherein The first coil stator assembly is configured to apply a first torque to the magnetic rotor assembly and the drive mechanism; and The transmission device is configured to transmit at least a portion of the first torque applied to the transmission device to the second coil stator assembly. 29. The drive system of claim 28, wherein the second coil stator assembly is configured to apply a second torque to the magnetic rotor assembly and the drive device. 30. The drive system of claim 29, wherein the drive mechanism is configured to prevent the first coil stator assembly and the second coil stator assembly from moving in response to the first torque and the second torque being equal in magnitude and in the same direction applied to the magnetic rotor assembly. 31. The drive system of claim 29, wherein the drive is configured such that the first coil stator assembly and the second coil stator assembly are movable in response to the first torque and the second torque being different in magnitude and/or applied in opposite directions to the magnetic rotor assembly. 32. A method for actuating a transmission system for a vehicle, the transmission system having a magnetic rotor assembly rotatable about a rotation axis, a first coil stator assembly rotatable about the rotation axis, and a second coil stator assembly rotatable about the rotation axis, the method comprising: A first torque is applied to the magnetic rotor assembly; In response to the application of the first torque, a second torque is applied to the first coil stator assembly; and At least a portion of the second torque is transmitted from the first coil stator assembly to the second coil stator assembly. The transfer of at least a portion of the second torque from the first coil stator assembly to the second coil stator assembly includes: At least a portion of the second torque is transmitted to the first swing arm, wherein one end of the first swing arm is rotatably connected to the first coil stator assembly; At least a portion of the second torque is transmitted from the first swing arm to the second swing arm; and At least a portion of the second torque is transmitted to the second coil stator assembly via a second swing arm, wherein one end of the second swing arm is rotatably connected to the second coil stator assembly. 33. The method according to claim 32, further comprising: A third torque is applied to the magnetic rotor assembly; and In response to the application of the third torque, a fourth torque is applied to the second coil stator assembly. 34. The method according to claim 33, further comprising: In response to the third torque and the fourth torque being of the same magnitude and applied in the same direction relative to the rotation axis, movement of the first coil stator assembly and the second coil stator assembly is prevented. 35. The method according to claim 33, further comprising: In response to the third torque and the fourth torque being of the same magnitude and applied in opposite directions relative to the axis of rotation, the first coil stator assembly and the second coil stator assembly are moved. 36. A transmission system for a vehicle, the transmission system comprising: Suspension arm; A rotary motor, coupled to the suspension arm such that the rotary motor is movable relative to the suspension arm, the rotary motor comprising: A magnetic rotor assembly that is rotatable about a rotation axis; A first coil stator assembly, rotatable about the rotation axis, is configured to apply a first torque to the magnetic rotor assembly and the suspension arm, wherein the first coil stator assembly is configured to apply the first torque to the suspension arm via a first link; and A second coil stator assembly, rotatable about the rotation axis, is used to apply a second torque to the magnetic rotor assembly. The second coil stator assembly is connected to the first coil stator assembly such that movement of the first coil stator assembly causes movement of the second coil stator assembly. Spindle, the spindle defining the axis of rotation; and A linear bearing that connects the main shaft to the suspension arm. 37. The drive system of claim 36, wherein one end of the first link is connected to the suspension arm at a first position, and the linear bearing is connected to the suspension arm at a second position different from the first position. 38. The transmission system according to claim 36, wherein the rotary motor moves along a defined path. 39. The drive system of claim 36, wherein the magnetic rotor assembly is configured to rotate in response to the first torque and the second torque being of the same magnitude and in the same direction applied to the magnetic rotor assembly. 40. The drive system of claim 36, wherein the rotary motor is configured to move relative to the suspension arm along a defined path in response to the first torque and the second torque being of the same magnitude and in opposite directions applied to the magnetic rotor assembly.