High torque density mechanical couplings with variable slip control

Abstract

Systems and methods are disclosed for high torque density mechanical couplings with variable slip control. The disclosed couplings can achieve order-of-magnitude (∼10x) improvements in torque density over existing magnetic and fluid options by leveraging combined normal, frictional, and inertial forces acting on sliding mechanical elements to transmit torque. The disclosed couplings can allow for continuous modulation of high-torque loads while naturally achieving lockup at maximum engagement and remaining well-suited to forced-convection cooling in high-heat-dissipation scenarios. Additionally, the disclosed couplings can be configured to achieve "one-way clutching" behavior while retaining the ability to speed-synchronize (transmit load under partial slip) and achieve lockup. These characteristics make the disclosed couplings well suited to a variety of applications and fields, including automotive and mobile robotics applications, such as active control of vehicle differential slip, where high torque density and slip control are both of critical importance.

Description

HIGH TORQUE DENSITY MECHANICAL COUPLINGS WITH VARIABLE SLIP CONTROLFIELD

[0001] This disclosure relates generally to mechanical couplings and, more particularly, to rotary couplings that connect two pieces of rotating equipment and enable the transmission of torque between them.BACKGROUND

[0002] A rotary coupling (or more simply, a coupling) is a mechanical device that connects two pieces of rotating equipment and enables the transmission of torque between them. Couplings date back to ancient times and are ubiquitous today, with some variant found in nearly every machine, from office printers, bicycles, and automobiles to steel mills, industrial pumps, and heavy-duty conveyor systems. Couplings fulfill the often-overlooked, yet crucial role of connecting rotating parts in the modem mechanical world. If a machine has a motor or engine, there is a good chance it also has at least one coupling.

[0003] In operation, a coupling transmits torque between two mechanical connections: its “input” and “output,” which are connected to a power source and mechanical load, respectively. Aside from transmitting torque, couplings can also provide several other benefits. These can include clutching, where torque transmission can be modulated or interrupted entirely. Other benefits can include compensation for differences in alignment and positioning of connected equipment, as well as allowing the transmission of uninterrupted torque despite changing positions or orientations of connected equipment. Further, couplings can provide isolation of loads other than the desired driving torque, and can protect against overload, undesired reverse operation, and / or system runaway.

[0004] Couplings are often designed from the ground up around their intended clutching behavior and can be classified into three “Mode Type” categories: Single-Mode couplings always operate in one configuration and torque cannot be modulated. Dual-Mode couplings can transition between two steady-state operating configurations. Finally, Variable-Mode couplings can traverse “through” different operating points, many of which can be sustained continuouslyin steady-state operation. Varying the level of coupling engagement can allow for modulation of the torque transmitted.

[0005] After Mode Type, two important metrics of coupling performance are torque capacity and size. These values, when combined, give a measure of a coupling’s “torque density.” Torque density is essentially a measure of volumetric efficiency, i.e., how effectively a coupling transmits torque given the packaging space afforded to it. At a given size, single-mode mechanical couplings often drastically out-perform dual-mode friction couplings and achieve — 10% higher torque. In turn, dual-mode friction couplings often drastically out-perform variable-mode couplings, again by a factor of — 10%. The torque capacity gap between singlemode and variable-mode couplings of the same size is substantial, often on the order of — 100%. In addition, at a given torque level, single-mode mechanical couplings are ~ 1 / 2 the diameter of equally rated dual-mode friction couplings, which are themselves ~ 1 / 2 the diameter of equally rated variable-mode couplings. Single-mode couplings are roughly — 1 / 4 the diameter of variable-mode couplings. Assuming roughly equal proportions, this corresponds to —1 / 64 the volume of variable-mode couplings.

[0006] Coupling performance is fundamentally limited by the underlying physics. The torque- dense, single-mode mechanical couplings not only achieve the highest torque ratings, but also span the widest range of available sizes. Many variable-mode couplings are non-viable for a particular application due to size constraints alone, even before considering their shortfalls in terms of torque capacity. The comparatively low torque density of variable-mode couplings is readily explained. For example, variable-mode hydrodynamic and magnetic couplings are fundamentally limited by commercially achievable material properties, specifically fluid density and magnetic maximum energy product. Friction clutches offer better torque density but are limited by their ability to continuously evacuate dissipated heat while slipping, especially at the friction interface. Cooling can be enhanced via fluid immersion and forced-convection, but this comes at the cost of a reduction in friction coefficient and torque capacity.

[0007] If a desired application requires substantial torque transmission while slipping continuously, a fluid or magnetic coupling is currently the preferred solution. Both are noncontact couplings and therefore exhibit minimal wear and excellent service life. For heavy-slipapplications, fluid couplings are particularly attractive because the working fluid can serve double-duty as a recirculating cooling agent. The governing physics of both fluid and magnetic couplings, however, fundamentally limit their achievable torque density. Further, the prohibitive size and weight of fluid and magnetic couplings frequently precludes their use in mobile and / or space-constrained applications. On the other hand, while friction clutches offer substantially greater torque capacity, they struggle to manage thermal loads while operating at continuous slip.

[0008] Further, there are situations where slip is unacceptable. The drawbacks of undesired slip include losses in efficiency, an inability to ensure synchronization of speeds and / or positions, generation of (potentially substantial) waste heat, and accelerated wear. In such cases, a “lockup-capable” coupling — which permits the input and output to be locked together with no slip — may be desired. In some cases, “slipping” and “lockup” couplings can be combined together in a single assembly to achieve the benefits of both in exchange for increased cost and complexity. Many modem automobiles combine fluid and friction elements in their transmissions for this very reason: the torque converter (a fluid coupling) will allow slip between the engine and transmission when idling, accelerating from rest, or shifting gears. Then, once the vehicle is up to speed, a separate parallel friction clutch mechanism locks out the fluid coupling and eliminates slip for more efficient cruising.

[0009] Accordingly, there is a need for improved couplings that can combine different aspects of existing rigid, friction, and fluid couplings to achieve both high torque density and variablemode operation, while facilitating efficient cooling.SUMMARY

[0010] The present disclosure provides a new kind of variable-slip mechanical coupling that utilizes rigid components to selectively transfer torque between coupled components. The couplings disclosed herein can achieve order-of-magnitude (~10x) improvements in torque density (i.e., torque capacity / coupling diameter) over existing magnetic and fluid options. The disclosed couplings leverage combined normal, friction, and inertial forces acting on sliding mechanical elements to realize the torque density improvement. The couplings disclosed herein can allow for continuous modulation of high-torque loads while naturally achieving lockup at maximum engagement and remaining well-suited to forced-convection cooling in high-heat-dissipation scenarios. Additionally, the couplings disclosed herein can achieve “one-way clutching” behavior while still retaining the ability to speed-synchronize (i.e., transmit load under partial slip) and achieve lockup. Accordingly, the couplings disclosed herein can have utility in a variety of fields, including automotive and mobile robotics applications, where high torque density and slip control are both important.

[0011] In one aspect, a coupling is provided that includes a rigid planet coupled to a first shaft and having a first slot formed therein. The coupling further includes a rigid orbit ring coupled to a second shaft and having a second slot formed therein, the orbit ring being disposed around the planet. The coupling also includes a rigid satellite with a first end disposed within the first slot of the planet and a second end disposed within the second slot of the orbit ring. The coupling can be configured to selectively transfer torque between the first shaft and the second shaft via normal and frictional force interactions between the satellite and each of the planet and the orbit ring.

[0012] Any of a variety of additional or alternative features can be included and are within the scope of the present disclosure. For example, in some embodiments, the first slot can extend parallel to a longitudinal axis of the first shaft.

[0013] In certain embodiments, the first slot can be curved relative to a longitudinal axis of the first shaft.

[0014] In some embodiments, a longitudinal axis of the satellite can intersect a center of the planet.

[0015] In certain embodiments, the planet can be spherical.

[0016] In some embodiments, the second slot can be formed along an inner circumference of the orbit ring.

[0017] In certain embodiments, the first shaft and the second shaft can be coaxial.

[0018] In some embodiments, the first shaft can extend in a first direction from the planet and the second shaft can extend in a second direction from the orbit ring that is different from the first direction.

[0019] In some embodiments, the orbit ring can be configured to rotate about an orbit tilt axis that is perpendicular to a longitudinal axis of the second shaft. In certain embodiments, the coupling can include an actuator coupled to the orbit ring and configured to control rotation of the orbit ring about the orbit tilt axis. In some embodiments, the orbit ring can be configured to rotate through an angular range of about 45 degrees in either direction from a first position in which the orbit ring defines a plane that is perpendicular to a longitudinal axis of the first shaft. In certain embodiments, the coupling can be configured to transfer torque between the first shaft and the second shaft with continuous slip over time based on an angle of rotation of the orbit ring about the orbit tilt axis.

[0020] In some embodiments, the planet can have a plurality of slots formed therein.

[0021] In certain embodiments, the coupling can include a plurality of satellites.

[0022] In some embodiments, the satellite can include a shaft, a lower block disposed around the shaft and configured to contact a radially-inner portion of the planet, an upper block disposed around the shaft and configured to contact a radially-outer portion of the planet, and an orbit block disposed around the shaft and configured to ride within the second slot of the orbit ring. In certain embodiments, one or more of the lower block, upper block, and orbit block can include an aperture for delivering lubrication to a surface in contact with another component of the coupling.

[0023] In certain embodiments, a center of the orbit ring can be offset from a center of the planet along a longitudinal axis of the first shaft.

[0024] In some embodiments, the coupling can further include one or more additional orbit rings disposed around the planet and offset from the orbit ring along a longitudinal axis of the first shaft. In certain embodiments, the one or more additional orbit rings can move together with the orbit ring. In some embodiments, the one or more additional orbit rings can move independently from the orbit ring.

[0025] In another aspect, a method is provided that includes rotating a first shaft extending from a coupling that includes a rigid planet, a rigid orbit ring disposed around the planet, and a rigid satellite riding in both a first slot formed in the planet and a second slot formed in the orbitring. The method further includes selectively transferring torque between the first shaft and a second shaft extending from the coupling via normal and frictional force interactions between the satellite and each of the planet and the orbit ring.

[0026] As with the couplings described above, any of a number of additional or alternative method steps can be included and are within the scope of the present disclosure. For example, in some embodiments, the method can further include adjusting an angle of the orbit ring about an axis that is perpendicular to an axis of rotation of the first shaft to vary an amount of continuous slip over time and thereby an amount of torque transferred between the first shaft and the second shaft. In certain embodiments, the angle of the orbit ring can be adjusted using an actuator coupled to the orbit ring.

[0027] In some embodiments, the method can further include lubricating an interface between the satellite and one or more of the planet and the orbit ring.

[0028] In certain embodiments, no torque is transferred between the first shaft and the second shaft.

[0029] In some embodiments, the first shaft and the second shaft rotate at a single speed.

[0030] In certain embodiments, the first shaft rotates at a first speed that is greater than a second speed of the second shaft. In other embodiments, the first shaft can rotate at a first speed that is less than a second speed of the second shaft.

[0031] In some embodiments, the first shaft and the second shaft rotate in the same direction.

[0032] In certain embodiments, the first shaft rotates in a first direction and the second shaft rotates in a second direction that is opposite the first direction.

[0033] In some embodiments, the method can further include adjusting the selective transfer of torque between the first shaft and the second shaft based on an amount of torque detected on the first shaft. In other embodiments, the method can further include adjusting the selective transfer of torque between the first shaft and the second shaft based on an amount of torque detected on the second shaft.

[0034] Any of the features or variations described herein can be applied to any particular aspect or embodiment of the present disclosure in a number of different combinations. The absence of explicit recitation of any particular combination is due solely to avoiding unnecessary length or repetition.BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The aspects and embodiments of the present disclosure can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0036] FIG. 1 is a perspective view of one embodiment of a coupling according to the present disclosure;

[0037] FIG. 2 is a top view of the coupling of FIG. 1;

[0038] FIG. 3 is a perspective view of a planet of the coupling of FIG. 1;

[0039] FIG. 4 is a perspective view of an orbit ring of the coupling of FIG. 1;

[0040] FIG. 5 is a perspective view of a satellite of the coupling of FIG. 1;

[0041] FIG. 6 is a perspective view of a planet and shaft of the coupling of FIG. 1;

[0042] FIG. 7 is a perspective, cross-sectional view of the planet and shaft of FIG. 6 taken along the plane A-A in FIG. 6;

[0043] FIG. 8 is a perspective view of an orbit ring and shaft of the coupling of FIG. 1;

[0044] FIG. 9 is a perspective, cross-sectional view of the orbit ring and shaft of FIG. 8 taken along the planer B-B in FIG. 8;

[0045] FIG. 10 is a perspective view of the coupling of FIG. 1 showing a rotation axis;

[0046] FIG. 11 is a perspective view of the coupling of FIG. 1 showing a planet rotation angle;

[0047] FIGS. 12(a)-12(c) show various views of the coupling of FIG. 1 in a first configuration;

[0048] FIGS. 13 (a)- 13 (f) show a top view of a motion sequence of the coupling of FIG. 1 in the first configuration of FIG. 12;

[0049] FIGS. 14(a)-14(f) show a perspective view of the motion sequence of FIG. 13;

[0050] FIG. 15 is a perspective view of the coupling of FIG. 1 in a second configuration;

[0051] FIG. 16 is a top view of the coupling of FIG. 15;

[0052] FIG. 17 is a detail view of the boxed portion of the coupling in FIG. 16;

[0053] FIGS. 18(a)-18(c) show various views of the coupling of FIG. 15;

[0054] FIGS. 19(a)-19(c) show various views of the coupling of FIG. 15 in a different rotational position;

[0055] FIGS. 20(a)-20(f) show a top view of a motion sequence of the coupling of FIG. 1 in the second configuration of FIG. 15;

[0056] FIGS. 21 (a)- 21 (f) show a perspective view of the motion sequence of FIG. 20;

[0057] FIGS. 22(a)-22(b) show various views of one embodiment of a coupling according to the present disclosure;

[0058] FIGS. 23(a)-23(c) show various views of one embodiment of a coupling according to the present disclosure;

[0059] FIG. 24 is a perspective view of the coupling of FIG. 23;

[0060] FIG. 25 is a perspective view of one embodiment of a coupling according to the present disclosure;

[0061] FIG. 26 is a perspective view of one embodiment of a coupling according to the present disclosure;

[0062] FIG. 27 is an alternate view of the coupling of FIG. 26 including controlling motor drivers and electronics;

[0063] FIG. 28 is a diagram showing components of the coupling of FIG. 26;

[0064] FIG. 29 is a side view of the coupling of FIG. 26;

[0065] FIG. 30 is a side, cross-sectional view of the coupling of FIG. 26;

[0066] FIG. 31 is a side, cross-sectional, detail view of portions of the coupling of FIG. 26;

[0067] FIG. 32 is a detail view of the coupling of FIG. 26;

[0068] FIG. 33 is a detail view of the boxed portion of the coupling in FIG. 32;

[0069] FIG. 34 is a perspective view of the orbit ring and outer frame of the coupling of FIG.26;

[0070] FIG. 35 is a perspective view of the orbit ring of the coupling of FIG. 26;

[0071] FIG. 36 is a perspective, cross-sectional view of the planet, orbit, satellites, and frame of the coupling of FIG. 26;

[0072] FIG. 37 is a perspective view of two halves of the planet of the coupling of FIG. 26;

[0073] FIG. 38 is a perspective, cross-sectional view of the planet of the coupling of FIG. 26;

[0074] FIG. 39 is a perspective view of the satellite of the coupling of FIG. 26;

[0075] FIG. 40 is a cross-sectional view of the satellite of FIG. 39 taken along the plane C-C in FIG. 39;

[0076] FIG. 40 is a detail, cross-sectional view of the orbit block of the satellite of FIG. 39;

[0077] FIG. 42 is a cross-sectional view of the planet and satellites of the coupling of FIG. 26;

[0078] FIG. 43 is a partial cross-sectional view of the planet, orbit ring, and satellites of the coupling of FIG. 26;

[0079] FIG. 44 is another partial cross-sectional view of the planet, orbit ring, and satellites of the coupling of FIG. 26;

[0080] FIG. 45 is another partial cross-sectional view of the planet, orbit ring, and satellites of the coupling of FIG. 26;

[0081] FIG. 46 is another partial cross-sectional view of the planet, orbit ring, and satellites of the coupling of FIG. 26;

[0082] FIG. 47 is another partial cross-sectional view of the planet, orbit ring, and satellites of the coupling of FIG. 26;

[0083] FIG. 48 is another partial cross-sectional view of the planet, orbit ring, and satellites of the coupling of FIG. 26;

[0084] FIG. 49 is another partial cross-sectional view of the planet, orbit ring, and satellites of the coupling of FIG. 26;

[0085] FIGS. 50(a)-50(l) show a perspective view of a motion sequence of the coupling of FIG. 26 with a set clutch angle and stationary planet;

[0086] FIGS. 5 l(a)-51(1) show a perspective view of another motion sequence of the coupling of FIG. 26 with a set clutch angle and rotation of planet and orbit in a same direction;

[0087] FIGS. 52(a)-52(l) show a perspective view of another motion sequence of the coupling of FIG. 26 with a set clutch angle and rotation of planet and orbit in opposite directions;

[0088] FIGS. 53(a)— 53(1) show a perspective view of another motion sequence of the coupling of FIG. 26 with a set clutch angle, stationary planet, and showing near-lockup of the coupling;

[0089] FIGS. 54(a)-54(e) show a side view of a motion sequence of the coupling of FIG. 26 with a variable, non-deterministically controlled clutch angle producing disengagement of the coupling;

[0090] FIGS. 55(a)-55(d) show a side view of another motion sequence of the coupling of FIG. 26 with a variable, non-deterministically controlled clutch angle producing lockup of the coupling;

[0091] FIG. 56 is a perspective view of one embodiment of a coupling according to the present disclosure in a first configuration;

[0092] FIG. 57 is a perspective view of the coupling of FIG. 56 in a second configuration;

[0093] FIG. 58 is a perspective view of one embodiment of a satellite according to the present disclosure;

[0094] FIG. 59 is a side view of one embodiment of a coupling according to the present disclosure;

[0095] FIG. 60 is a side view of one embodiment of a coupling according to the present disclosure; and

[0096] FIG. 61 illustrates one embodiment of a satellite according to the present disclosure.DETAILED DESCRIPTION

[0097] Certain example embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices, systems, and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. The devices, systems, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting embodiments. The features illustrated or described in connection with one embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure.

[0098] As noted above, a coupling transmits torque between two mechanical connections: its “input” and “output,” which are connected to a power source and mechanical load, respectively. The terms “input” and “output” indicate the direction of instantaneous torque transmission. Torque transmission is often unidirectional, though this is not always the case. In manyapplications, torque may “flow” in either direction depending on the immediate circumstances. For example, when an electric vehicle utilizes regenerative braking, its wheels briefly become the torque inputs and back-drive their motor(s) for energy recovery (most of the time, power flows the other way — out from the motors to the wheels).

[0099] Couplings play important roles in industrial applications, where large loads, inertias, and energies involved necessitate paying attention to the mechanical connections between equipment. Example applications include: misalignment couplings for motors; hoist clutches for cranes; torque-limiting couplings for roller tension control in metal-forming processes; overrunning clutches for marine drives; safety couplings for conveyor systems; tension control in filament manufacture; fluid couplings for smooth startup of heavy equipment (e.g., electrical generators); and many others.

[0100] An important decision to be made when selecting a coupling is choosing whether clutching capability is needed. This includes determining if the coupling must be capable of fully engaging and fully disengaging torque transmission, as well as determining if it must be capable of running partially engaged and able to actively moderate torque by continuously varying the level of engagement. Couplings are usually designed from the ground-up around their intended clutching behavior (or lack thereof). As a result, the choice of coupling “Mode Type” imposes constraints onto nearly every other performance characteristic. Couplings can be classified into three categories based on their clutching / non-clutching behavior:

[0101] First are Single-Mode or “Permanent Couplings” that always operate in one configuration and torque cannot be modulated. This category includes most non-friction couplings (rigid, alignment-compensating, one-way, etc.), as well as constant-fill fluid couplings and synchronous magnetic couplings. Note that many permanent couplings can still slip, but the level of slip cannot be controlled via direct manipulation of the coupling.[Of 02] Second are Dual -Mode or “Digital Clutches” that can transition between two steadystate operating configurations. Partial engagement can occur briefly during mode transition (i.e., speed synchronization, such as shifting gears in an automobile). Especially for friction clutches, these transients must be short, infrequent, and specifically designed to avoid overheating and damage. This category includes most friction clutches, some synchronous magnetic couplings,and some rigid couplings (e.g., tooth clutches). Note that although Dual-Mode couplings can (dis)engage, they cannot necessarily perform speed-synchronization on their own (tooth clutches again serve as a good example).

[0103] Third are Variable-Mode or “Analog Clutches” that can traverse “through” different operating points, many of which can be sustained continuously in steady-state operation (subject to other constraints, such as the thermal limits of the design). Varying the level of coupling engagement allows for modulation of the torque transmitted. This category includes many variable-fill fluid couplings, variable-magnetic couplings, and certain specialty friction clutches.

[0104] As noted above, two important metrics of coupling performance are torque capacity and size. These values, when combined, give a measure of a coupling’s “torque density.” Torque density is essentially a measure of volumetric efficiency, i.e., how effectively a coupling transmits torque given the packaging space afforded to it. At a given size, single-mode mechanical couplings often drastically out-perform dual-mode friction couplings and achieve ~10x higher torque. In turn, dual-mode friction couplings drastically out-perform variable-mode couplings, again by a factor of ~10x. The torque capacity gap between single-mode and variable-mode couplings of the same size is substantial: ~100x. This factor is so large that a particular application must demonstrate critical need for variable-mode operation to justify the selection of such a coupling. In addition, at a given torque level, single-mode mechanical couplings are ~ 1 / 2 the diameter of equally rated dual-mode friction couplings, which are themselves ~ 1 / 2 the diameter of equally rated variable-mode couplings. Single-mode couplings are roughly ~ 1 / 4 the diameter of variable-mode couplings and, assuming roughly equal proportions, this corresponds to ~ 1 / 64 the volume of variable-mode couplings.

[0105] Torque-diameter scaling is a third-order relationship (T oc3) so torque capacity scales roughly proportionally with coupling volume. This relationship holds steady regardless of coupling type or size. In other words, coupling performance is fundamentally limited by the underlying physics. This also means that continued iteration on current designs of fluid / magnetic couplings is unlikely to produce variable-mode couplings with massively improved performance (vs. the current benchmarks).

[0106] The torque-dense, single-mode mechanical couplings achieve the highest torque ratings and also span the widest range of available sizes. Many variable-mode couplings are non-viable due to size constraints alone, even before considering their shortfalls in terms of torque capacity. As noted above, the comparatively low torque density of variable-mode couplings is readily explained. Hydrodynamic and magnetic couplings are fundamentally limited by commercially achievable material properties, specifically fluid density and magnetic maximum energy product. Friction clutches offer better torque density but are limited by their ability to continuously evacuate dissipated heat while slipping, especially at the friction interface. Cooling can be enhanced via fluid immersion and forced-convection at the cost of a reduction in friction coefficient and torque capacity. Even then, friction clutches are overwhelmingly used in dualmode applications where slip events are brief and infrequent.

[0107] Clutch (dis)engagement and slip are two sides of the same coin, with slip being the phenomenon that occurs during the process of coupling (dis)engagement. In the example of a stick-shift car, precise clutch control (slip control) is what makes smooth takeoffs and gearshifts possible. Particularly in industrial applications, coupling (dis)engagement allows many power sources and / or loads to be connected together on-demand to form mechanical networks. Slip is also useful for reasons beyond clutching. In fluid and magnetic couplings, the ability to slip serves as a safeguard against shock / overload, dampens torsional vibrations, and passively facilitates smooth acceleration and deceleration of high-inertia loads. Safety couplings (one-way couplings, torque-limiting couplings, etc.) specifically slip in certain conditions and lock in others. For example, backstopping clutches are used in inclined conveyor systems for raw materials. In normal operation, the backstopping clutch slips and permits the conveyor to transport material up an incline. If the drive ever fails, the backstopping clutch locks up and prevents the conveyor from running backwards, thereby avoiding potentially catastrophic reverse-runaway.

[0108] As noted above, if substantial torque must be transmitted while slipping continuously, a fluid or magnetic coupling is currently the preferred solution. Both are non-contact and therefore exhibit minimal wear and excellent service life. For heavy-slip applications, fluid couplings are particularly attractive because the working fluid can serve double-duty as a recirculating cooling agent. The governing physics of both fluid and magnetic couplings, however, fundamentallylimits their achievable torque density. For large stationary applications (e g. chemical plants, power plants, factories), size and weight are not always crucial design constraints and this drawback may not be as substantial. The prohibitive size and weight of fluid and magnetic couplings frequently precludes their use in mobile and / or space-constrained applications, however. On the other hand, friction clutches offer substantially greater torque capacity but they struggle to manage thermal loads while operating at continuous slip.

[0109] While coupling slip can be useful, there are also situations where slip is unacceptable. The drawbacks of undesired slip can include losses in efficiency, an inability to ensure synchronization of speeds and / or positions, generation of (potentially substantial) waste heat, and accelerated wear. In such cases, a “lockup-capable” coupling, which permits the input and output to be locked together with no slip, can be desired.

[0110] Returning to the example of a stick-shift car, clutch slip is essential during key periods such as takeoff, gearshifts, etc. Outside of these short events, however, the clutch should lockup such that there is no slip between the engine and transmission. Lockup maximizes the power delivered to the wheels, preserves consistent and predictable throttle response, improves fuel efficiency, and most importantly, avoids needless clutch heating and wear. When operated correctly, a clutch can last tens of thousands of miles, but less than a minute spent “slipping the clutch” (uninterrupted) can permanently damage it and require replacement.

[0111] “Slipping” and “lockup” couplings can be combined together in a single assembly to achieve the benefits of both in exchange for increased cost and complexity. Many modern automobiles combine fluid and friction elements in their transmissions for this very reason: the torque converter (a fluid coupling) will allow slip between the engine and transmission when idling, accelerating from rest, or shifting gears. Then, once the vehicle is up to speed, a separate parallel friction clutch mechanism locks out the fluid coupling and eliminates slip for more efficient cruising.

[0112] This disclosure introduces a new type of mechanical coupling having high torque density and variable slip control, referred to herein as an Inertial Hysteresis Coupling (IHC), for which a schematic example is shown in FIG. 1. The IHC is a variable-slip coupling / clutch that aims to achieve similar functionality to existing magnetic and fluid options, but withsubstantially greater torque capacity and the in-built capacity to attain full lockup (i.e., zero slip). IHCs seek to enable widespread use of torque-dense variable-slip couplings in robotics and vehicle applications, among others, where the size and weight of existing variable-slip couplings makes their use prohibitive. IHCs achieve their improved torque density by harnessing normal and frictional forces developed between sliding contact surfaces of rigid mechanical components to efficiently transmit loads (i.e., driving heavy loads even with low friction coefficients) while using a geometry that is much easier to cool compared to friction clutches. Peak torque in these couplings is therefore limited by material strength rather than fluid or magnetic properties. Compared to existing magnetic / fluid couplings, this can allow for torque density improvements of 2-10 or more. In effect, IHCs combine different aspects of rigid, friction, and fluid couplings to achieve high torque density and variable-mode operation, while facilitating efficient cooling. IHCs allow coupling torque and speed to be actively modulated, while transmitting I Ox (or more) the torque of fluid / magnetic couplings and dissipating heat far better than friction couplings. They can behave similarly to a fluid coupling, but use mechanical elements instead. Forces are transmitted using rigid mechanical elements that are allowed to slip in a controlled fashion. This permits very high torque loads to be transmitted while still permitting fully variable slip control. The trajectory of the slipping rigid mechanical elements can be actively controlled to adjust the level of slip in the coupling. At maximum engagement, the elements can bind and the coupling can be fully locked. The IHC concept is a major departure from the design of any existing coupling and represents a novel approach to torque transmission.

[0113] The couplings disclosed herein can include fully adjustable engagement, including active variable control of the engagement state from 0-100% with continuous operation and adjustment permitted at any slip rate. IHC designs can naturally achieve full lockup (i.e., zeroslip) without any separate mechanisms, which is in contrast to existing variable-slip couplings that require additional mechanisms to run at zero-slip. Further, certain embodiments can achieve auto-engaging (emergency brake) or auto-disengaging (overload protection) behaviors. No existing coupling can achieve both variable-slip behavior and inherent full lockup, especially while delivering the levels of torque capacity possible with the IHCs disclosed herein.

[0114] Couplings are virtually ubiquitous devices, found nearly everywhere machinery performs useful work. Every existing major coupling type sees widespread use across a varietyof industries. Thus, the potential applications for IHCs are quite numerous, especially given the magnitude of performance improvement achieved with the couplings disclosed herein. Additionally, many future technologies may be enabled specifically as a result of the capability provided by the couplings disclosed herein. Example areas offering great potential impact include those that would leverage the performance advantages of IHCs, i.e., active modulation of torque transmission; efficient cooling via forced fluid convection; and a compact, high torque density footprint. Applications that would particularly benefit from these qualities include those that simultaneously demand wide operating flexibility, high torque capacity, and excellent size / weight characteristics. The automotive and mobile robotics markets are two examples of fields where these factors are given high priority.

[0115] One example application of IHCs in the automotive market is in next-generation mechanical torque vectoring systems (e.g., all-wheel-drive systems, active differentials, and / or torque-vectoring features). IHCs can vector engine / motor torque between driven wheels, continuously and without overheating. Existing state-of-the-art drivetrains (using friction clutches) have drawbacks, including issues with dissipating heat that can limit operation to only a few seconds before overheating. This can impose severe limitations when it comes to high- duty-cycle use. For example, common clutch friction materials experience significant performance degradation and accelerated wear when temperatures surpass ~200°C — a threshold which is rapidly breached under heavy load. As a result, these systems work best under only moderate, intermittent loading. This can make them unsuitable for high-torque applications (e.g., EVs, trucking, etc.) and high-demand (i.e., continuous-use) applications. There are no other options in the automotive sector currently, so these compromises are accepted.

[0116] Further, the ability to fully lock up means torque-vectoring IHCs can double as locking differentials for off-road and other low-traction conditions, without any additional hardware. Unlike existing locking differentials, which must be manually engaged at low speeds (often only while stopped), the lockup of an IHC can be fully automated by the vehicle computer (e.g., traction control / stability control systems) and can lockup at any speed.

[0117] Another example area of application includes industrial pumping applications, such as used in water utilities, mining, and power generation. These applications can require high-efficiency, overload-protected couplings. Industrial pumps are typically driven by motors through hydrodynamic or magnetic couplings to provide overload protection in the event the pump seizes. These couplings do not directly connect motor and pump, but instead use fluid or magnetic forces to transmit torque. If one component seizes up, the other may continue spinning without damage. These couplings inherently slip, however, and at their best operating point only achieve -96% efficiency. The IHCs disclosed herein can allow nominal operation fully engaged (i.e., zero slip, 100% efficiency), but can open and decouple motor and load in the event of a torque overload. Thus, at worst an IHC would represent a 4% absolute efficiency gain over existing couplings. Many couplings, however, do not operate exactly at their efficiency peak and may achieve, e.g., 75% efficiency or less. In such cases, the efficiency improvement by using an IHC is substantially greater. Moreover, slipping couplings are also used to assist with equipment startup so that the motor may get up to speed before engaging the majority of the load. Because the IHC is fully variable and can run from 0-100% engagement, this behavior is maintained. This behavior is not possible with other direct-drive overload-protection devices, such as shear pins.

[0118] Still another example area of application includes robotics, which can require clutches, variable-impedance actuators, and overload protection. The list of potential applications continues though. Other example applications include marine driveline protection, which can include resettable propeller overload protection, smooth startup, and smooth power-source changeover (e.g., between diesel, electric, and steam propulsion). Another area of application is material handling and industrial conveyor systems, including warehousing, providing safety brakes on industrial conveyor systems in a variety of industries (e.g., mining), etc. Still another area of application is in hoisting, winching, and lifting systems, where the couplings disclosed herein can provide runaway braking systems, smooth engagement during initial lifting / pulling, etc.

[0119] Turning to FIGS. 1-17, a schematic example of an IHC or coupling 100 according to the present disclosure is shown. The coupling 100 can include three major subassemblies: First, a “planet” 102, analogous to the “pump” in a fluid coupling. Second, an “orbit” 104, analogous to the “turbine” in a fluid coupling. Third, a “satellite” 106, which acts as the connecting object, analogous to the “working fluid” in a fluid coupling. The components’ names are based on theloose resemblances to their namesakes: The planet 102 can be a sphere with a slot 112 formed therein. The orbit 104 can be a ring with slot 114 formed around an inner circumference thereof. The satellite 106 can be a peg or cylinder with a first end disposed in the slot 112 and a second end disposed in the slot 114. The planet 102 and orbit 104 can function as the IHC input and output via a first shaft 108 coupled to the planet 102 and a second shaft 110 coupled to the orbit 104. The planet 102 and orbit 104 can be positioned such that their centers are co-located and their associated shafts 108, 110 can extend in opposite directions along a common central axis Ai.

[0120] For simplicity in the following disclosure, the orbit 104 will remain fixed in place while the planet 102 and satellite(s) 106 move (in practice, both the planet and orbit can rotate independently). In terms of degrees-of-freedom, the planet 102 and orbit 104 can each only rotate about their shaft axis Ai; all other degrees-of-freedom can be constrained. Finally, the satellite 106 runs along the planet and orbit slots 112, 114, sliding freely within each of them and always pointing towards the center of the planet 102. The satellite 106 is assumed to have nonzero mass and non-zero friction coefficient (i.e., it can experience normal, frictional, and inertial forces).

[0121] Input power can be supplied to the planet 102 via the first shaft 108, which can rotate about its central axis Ai and drive one or more satellites 106. Each satellite 106 can slide along a track or slot 112 in the planet 102, while also traversing a track or slot 114 formed in the larger orbit ring 104. As the planet 102 spins, the one or more satellites 106 experience continuous acceleration and deceleration as they track along both the planet and orbit constraints. In the process, the one or more satellites 106 interact with the planet 102 and orbit ring 104 by means of normal and frictional forces. These interactions produce net torque transmission across the device, allowing the planet 102 to drive the orbit 104 via the one or more intermediary satellites 106. The planet 102 and orbit ring 104 do not touch one another directly. Instead, each satellite 106 has a first end disposed within the slot 112 of the planet 102 and a second end disposed within the slot 114 of the orbit ring 104.

[0122] The coupling 100 relies on its one or more satellites 106 to transmit torque. The one or more satellites 106 are inertial masses; they not only transmit contact loads from the planet / orbit,but also induce inertial loads due their non-zero mass. The presence of some friction is also part of this process because, without friction, average torque transmission can sum to zero (i.e., the mechanism can cycle between equal periods of positive and negative torque, averaging to zero). The hysteresis that friction provides is ultimately important to the coupling’s functionality, hence the name Inertial Hysteresis Coupling (IHC).

[0123] The one or more satellites 106 each move as rigid mechanical “sliding connectors” and they experience kinetic friction in doing so. A wide contact area can be utilized to reduce contact stress, to maintain a supporting lubricant film, and to achieve a long wear life. In addition, the incident angles / friction contact angles can be manipulated to modulate the friction forces produced. While slipping, the presence of a lubricant can reduce friction and wear, and also serve as a convective cooling agent. The sliding contact surfaces of the planet 102, orbit ring 104, and one or more satellites 106 can be continually flushed with oil or the entire mechanism can be submerged in an oil bath. When the incident angle falls below a critical threshold, the sliding connector or satellite 106 can lock in place and the input / output shafts 108, 110 can be rigidly linked. While locked in this fashion, the load capacity of the device 100 as a whole is ultimately limited by the mechanical strength of its parts (the same limitation that applies to rigid single-mode couplings). Finally, because most of the coupling load is supported by normal contact forces (which remain effective even with very low friction coefficients, < 0.05), the materials selection process can favor high -temperature, high-wear-resistance materials such as hardened steels and bearing bronzes. This is in contrast to friction couplings, which transmit 100% of their torque via friction and frequently use much less resilient organic friction materials.

[0124] In short, the “sliding connector” concept of the satellite 106 combines several of the key desirable aspects of various existing coupling types: Like variable-mode fluid couplings, the concept can modulate slip and is readily adapted for convective cooling. Like dual-mode friction couplings, the concept can transition into full lockup (i.e., zero slip). Like single-mode rigid couplings, the concept is fundamentally limited by the mechanical strength of its rigid materials rather than fluid or magnetic properties. This enables potentially order-of-magnitude improvements in torque density over existing variable-slip couplings.

[0125] Returning to the embodiment shown in FIGS. 1-14, a first configuration is shown where the orbit ring 104 is exactly aligned with the “equator” of the planet 102. When the planet 102 rotates, the satellite 106 follows a simple path and advances through the orbit 104 at constant speed. The satellite 106 does not move relative to the planet 102 and it experiences no lateral forces or acceleration. With no normal force acting between the satellite 106 and the orbit 104 sidewalls, there is no friction and the satellite moves without resistance. In other words, for this example configuration, this is a minimally engaged or fully disengaged state where no torque is transmitted and the two shafts fully slip relative to one another. This is also a state that can serve as an auto-disengaging or freewheeling setting in the event of overload, etc.

[0126] FIGS. 12(a)-12(c) show various views of the coupling 100 in this first configuration, including a detail view in FIG. 12(c) showing the orbit contact line OCL drawn between the two points of contact of the satellite 106 with the orbit ring 104. The figure also shows the planet contact line PCL drawn between the two points of contact of the satellite 106 with the planet 102, and the contact angle difference CAD between the two lines.

[0127] FIGS. 13 (a)- 13 (f) and 14(a)- 14(f) show a motion sequence of the coupling 100 in the first configuration. The figures show the planet 102 rotating with the satellite 106 while the orbit ring 104 remains stationary.

[0128] FIGS. 15-21 illustrate another embodiment in which the orbit ring 104 has been tilted by 40° (angle o) from the configuration of FIGS. 1-14 about an orbit tilt axis A2 that is perpendicular to the longitudinal axis Ai. Although the orientation of the orbit ring 104 has changed, the component as a whole can still only rotate about the same central axis Ai as the planet 102. The tilt of the orbit ring 104 can be subtle but can have numerous cascading effects. These include the fact that the satellite 106 no longer moves along the “equator” of the planet 102. It still moves through the orbit’s circular path but the motion is now inclined with respect to the planet. It moves across the planet’s “equator” at rotation angles of 0° and 180°, as shown in FIGS. 20(a) and 20(d). The apparent orbit-satellite contact angle is no longer constant and now varies with position. It is most inclined at angles 0° and 180° and most shallow at angles 90° and 270°.

[0129] The satellite 106 no longer moves at constant velocity, which may not be an intuitive result. In the images shown, consider the location of the satellite’s center-of-mass (CM), which can be assumed to be halfway along its length. In certain locations (e.g., 90° and 270°), the CM is close to the planet / orbit rotation axis Ai, while at others (e.g., 0° and 180°) it is farther away. If the planet 102 driving the satellite 106 maintains a constant angular speed, the satellite’s absolute speed must vary based on its distance from the rotation axis Ai. Therefore, the satellite 106 must undergo cycles of acceleration and deceleration. The normal and frictional contact forces are the only loads acting laterally on the satellite 106, so they must drive this acceleration / deceleration process. The equal and opposite reactions must then be acting on the planet 102 and orbit 104, meaning some net transmission of torque from planet to orbit occurs.

[0130] The close-up cutaways pictured in FIGS. 18(b) and 18(c) hint at a mechanism for achieving lock-up and positive engagement in the coupling 100. The illustrated configuration can be analogized to that of a block on a shallow inclined plane. When the inclination angle gets low enough, the block can no longer slide from purely vertical applied load. This foreshadows that satellites 106 can exhibit critical contact angles beyond which they will lock up and be unable to slip (producing a zero slip rate between the planet 102 and orbit ring 104), no matter how much load is imposed. Note that all of these effects occur simply by tilting the orbit ring 104 about the tilt axis A2. This tilt corresponds to what can be referred to as the IHC “clutch angle,” or (io. In the examples of FIGS. 1-24, the orbit ring 104 is shown as fixed in place in a given configuration, but these are simplified schematic illustrations and, in practice, the clutch angle can be actively controlled to smoothly modulate torque transmission (see, e.g., the embodiments of FIGS. 25-57).

[0131] Accordingly, transmitted torque in an IHC coupling can be modulated by varying the clutch angle (io. For example, the clutch angle (io can be moved between a first configuration, wherein the clutch angle (io is zero (as shown in FIGS. 1-14) and no torque is transmitted, and a second configuration, wherein the clutch angle (io is sufficiently high (as shown in FIGS. 15-21) to produce lockup where all available torque is transmitted without slip between the two shafts.

[0132] FIGS. 20(a)-20(f) and 21(a)-21(f) show a motion sequence of the coupling 100 in the second configuration. The figures show the planet 102 rotating with the satellite 106 while theorbit ring 104 again is held stationary so the path of the satellite 106 through the slots 112, 114 can be visualized.

[0133] In the embodiment of FIG. 22, a coupling 100' with similar geometry to coupling 100 is employed, but five more satellites 106 are added, each running in their own evenly spaced planet slots 112. The use of multiple satellites 106 can be a natural extension to the concept, and can have many benefits. For example, greater torque can be transmitted because more satellites 106 carry load at each moment in time. Additionally, certain loads from opposing satellites 106 can cancel one another out due to symmetry, thereby reducing vibration and bearing loads. Further, a single satellite 106 can result in a strongly cyclical torque output, i.e. significant torque ripple. With many satellites 106 in one system, the total coupling torque can be “handed off’ between individual satellites 106 and the net torque output can be smoothed. Multiple satellites can therefore be used to optimize for torque ripple and balance.

[0134] In the embodiment of FIG. 23, a coupling 100" with similar geometry to coupling 100' is shown, but a change is made in the shape of the planet slot 112. This change can have far- reaching implications in terms of modeling, design, fabrication, assembly, etc. Functionally, it can allow the satellite 106 to achieve extremely shallow contact angles, such as those shown in FIG. 23(c), where the OCL and PCL lines are nearly parallel. Even for very low coefficients of friction, such shallow contact angles can allow high forces to be developed and lockup to be achieved. Whereas the contact angles in the examples above were limited by the rotation range of the orbit ring 104 about the tilt axis A2, this embodiment allows arbitrarily shallow contact angles to be obtained by modifying the shape of the slots 112 formed in the planet 102. In other embodiments, any of a variety of different shapes for the planet slot 112 can be utilized. Examples can include use of alternate arc shapes, angled shapes, shapes with geometric asymmetries, etc.

[0135] FIG. 24 illustrates one example coordinate system that can be used when describing motion of the IHC / coupling 100" and its components. In the illustrated embodiment, the X-axis coincides with the axis Ai noted above about which the planet 102 and orbit 104 (and their associated shafts 108 and 110) rotate. The center of the planet 102 lies at the (X, Y, Z) = (0, 0, 0) point in the illustrated embodiment, and the planet’s “equatorial plane” coincides with the X =0 plane. Further, in the illustrated position, the orbit tilt axis A2 noted above coincides with the Z-axis.

[0136] FIG. 25 illustrates one embodiment a coupling 200 according to the present disclosure. The illustrated embodiment includes a planet 202 that is about 2” (50 mm) in diameter. Similar to the embodiment shown in FIG. 23, the planet 202 includes a plurality of curved slots 212 formed therein that can each receive a portion of a satellite (not visible). The coupling 200 otherwise includes components similar to the coupling 100 described above, including an orbit ring 204, a first shaft 208 coupled to the planet 202, and a second shaft 210 coupled to the orbit ring. The coupling 200 also includes a cam lever lock 220 that can be used to selectively permit the adjustment of the orbit tilt angle about the orbit tilt axis A2.

[0137] FIGS. 26-55 illustrate another embodiment of a coupling 300 according to the present disclosure. Mechanically, the system consists of two rotating subassemblies, 301, 303 organized along a common rotation axis AL The Inertial Hysteresis Coupling 300 is centrally located and supported on either side by bearing uprights 322 that resemble tombstones. Geared stepper motors 324, 326 are mounted at either end of the system and each drives one of the rotating subassemblies 301, 303. FIG. 29-31 contain side-views of the coupling, in which the “right” motor 324 (right-hand side in the figure) drives the planet 302 (and associated subassembly 301) by means of a splined driveshaft. The “left” motor 326 (left-hand side in the figure) drives both the in-line torque sensor 328 and the orbit ring 304 (and associated subassembly 303). The coupling 300 is mounted upon a baseplate 330 that can be bolted to a substrate, such as a table, etc.

[0138] FIGS. 27 and 28 illustrate alternative schematic views of the coupling 300 and associated components. These include the physical components and the motor drivers and control electronics 327.

[0139] An additional degree-of-freedom — modulation of the clutch angle (io — is built into the orbit subassembly 303. In particular, the orbit ring 304 is mounted on a frame 332 by dowel pins 329 (see FIG. 36) and can swivel to change the clutch angle (io. Once the desired position is found, four bolts 345 can be tightened to lock the clutch angle for use under load. The illustrated embodiment is a relatively simple manual mechanism for adjusting and locking the clutch angle(io. In other embodiments, any of a variety of alternative mechanisms can be utilized. These can include mechanisms that allow for adjustment of clutch angle during use, such as the embodiment discussed below in connection with FIGS. 56 and 57. Note that various approaches to adjusting the clutch angle (io exist, including, for example, deterministic approaches in which the clutch angle is set at a given value and feedback-style mechanisms in which conditions experienced in the IHC coupling produce variations in the clutch angle (io. Example control mechanisms can include computer-controlled mechanisms that adjust clutch angle (io in response to measured torque and / or speed, or a mechanical analog.

[0140] In the illustrated embodiment, the planet 302 has a diameter of about 6 inches (about 150 mm) and includes two identical half-spheres 302a, 302b (see FIG. 37) joined together via alignment pins and fasteners. The fasteners clamp the planet halves 302a, 302b together through rectangular hubs 334 protruding from either end of the planet (along its rotation axis Ai).

[0141] Example materials for forming the planet 302 can include A3 tool steel, M303E high- chromium steel (corrosion-resistant but not stainless), POM (Polyoxymethylene 1), PBT (Polybutylene Terephthalate), PA6 Nylon (Polyamide), and PA66 Nylon (Polyamide). In the illustrated embodiment, POM was chosen for excellent lubricity (low coefficient of friction), excellent wear and abrasion resistance, non-hygroscopic nature (aversion to moisture absorption), and excellent chemical resistance (compatibility with a wide range of lubricants and cleaning products). Note that the above-noted example materials were candidates for the illustrated IHC embodiment. Implementations of IHCs in industrial applications are likely to utilize different materials for reasons associated with cost, performance, manufacturability, etc. Utilization of other suitable materials is within the scope of the present disclosure.

[0142] As shown in FIG. 38, the hole pattern on the “left” planet hub (i.e., left-hand side shown in FIGS. 29 and 30) can mate to a splined flange coupling 336, which in turn drives a splined shaft 308 (e.g., a 25 mm six-groove shaft in the illustrated embodiment). This connects the planet 302 to the driveshaft 308. The coupling-shaft connection can sustain 200+ Nm of torque. Unlike a setscrew or machine key, the six splines transfer load in a radially symmetric fashion, greatly reducing the risk of unexpected damage to the planet in the event of shock loading. Steel threaded inserts can be used for the four threaded holes comprising the planet-coupling connection. This can allow large MIO x 1.5 threads to be tapped into the (plastic in this embodiment) planet to reduce the likelihood of accidental thread damage during assembly or operation. The planet-coupling connection is made using four M6 x 1.0 fasteners in this embodiment. The illustrated configuration is just one example, however, and any of a variety of alternative configurations can also be employed and are considered within the scope of the present disclosure.

[0143] A 3D printed splined spacer 338 can be seen in FIG. 38. This spacer 338 can be used for radial support between the planet 302 and its driveshaft 308. Being 3D printed, the spacer 338 easily accomplishes interfacing with the six grooves of the splined shaft 308.

[0144] FIGS. 34-36 illustrate the various assemblies associated with the orbit 304. The orbit includes two subassemblies shown in FIG. 34: the orbit ring 304 itself and an outer frame 332 in which the orbit ring 304 is mounted. Torque to / from the orbit ring 304 can be transmitted via an output shaft 310 coupled to the frame 332.

[0145] Both subassemblies of FIG. 34 can use “sandwich” construction to reduce costs and manufacturing complexity, though other configurations are possible in alternative embodiments. Returning to the illustrated embodiment, Aluminum 6061-T6 plates can be cut using a wateijet and can serve as outer plates 333. Beneath the orbit ring’s outer plates 333 can be a set of 3D printed orbit tracks 335. In alternative embodiments, the tracks can be machined, e.g., from a lubricant-impregnated nylon 6 / 6 or other material. The tracks can also include regularly spaced pockets 337 for retaining lubricant.

[0146] The orbit ring 304 can include a removable track section 339, as shown in FIG. 35. This removable section can provide access to the satellites 306. This access can allow various adjustments, replacements, etc., and can facilitate the installation and removal of satellite orbit blocks. When the removable section of track 339 is replaced, its track surfaces can be set flush with the remainder of the tracks 335 to avoid any impediment to smooth passage of a satellite around the orbit ring 304.

[0147] The orbit ring 304 and its outer frame 332 connect via swivel blocks 341 at their tops and bottoms, as shown in FIG. 34. As noted above, modulation of the IHC clutch angle ?o canbe provided by a pair of 3 / 8” diameter dowel pins 329 (see FIG. 36) that sit in bores 343 (see FIG. 35) and enable the swiveling motion. Four screws 345 (two per side) can be threaded into bores 347 and allow the clutch angle to be locked in place for use under load. Clutch angle (JO can be measured manually using a handheld digital protractor in the illustrated embodiment. For example, the protractor can be laid against the aluminum plates of the orbit ring 304 and the outer frame 332 and the angle reading recorded. This can be repeated at each corner on both the front and back of the orbit assembly, giving eight total measurements. This can produce repeatability better than ±0.6°. In other embodiments, a measurement instrument can be integrated into the orbit assembly, which can be capable of faster and / or more accurate measurements. Such a sensor or measurement instrument can also be incorporated into embodiments that provide powered clutch angle adjustment, such as the embodiment of FIGS. 56 and 57 described below.

[0148] In the embodiment of FIGS. 26-55, NEMA 34 stepper motors and 5:1 planetary gearboxes 324, 326 can drive the coupling 300. The same motor and gearbox are shown on both ends, though this is for testing purposes. In use, the input / output can be coupled to any of a variety of energy sources and loads to provide useful functionality. In the testing environment of the illustrated embodiment, the motor 324 can drive the system while the motor 326 holds position (behaving as a non-moving load).

[0149] FIGS. 39-49 show a satellite 306 in greater detail and in relation to other components of the coupling 300. Each satellite 306 can include four major components: three tapered blocks 340, 342, 344 and a central shaft 346, as shown in FIG. 39. The lower two blocks 340, 342 are the “planet” blocks, including a lower planet block 340 and an upper planet block 342. These two blocks clamp to the planet 302, which has a corresponding tapered slot 312 formed therein. A preload force can be provided by a spring 348 (e.g., a wave disc spring) acting on the lower planet block 340, which can “squeeze” the planet blocks 340, 342 into their slot 312, as shown in FIGS. 40 and 45-47. The outer block 344 is the “orbit” block, which slides inside the corresponding tapered slot 314 in the orbit ring 304. A preload force can be provided by a spring 350 (e.g., a wave disc spring), which can press the orbit block 344 radially outwards into the orbit track slot 314, as shown in FIGS. 40, 43, 48, and 49. The shaft 346 serves as the core structure of the satellite 306. It lies coaxial to the satellite “intersection line” or longitudinal axis.

[0150] As can be seen in FIGS. 39-49, each satellite block 340, 342, 344 is tapered. The two preload forces mentioned above can ensure each block is continuously pressed into its corresponding mating slot, which can eliminate potential backlash from fabrication, assembly, etc. The preload forces can be provided by springs 348, 3 0, as noted above. Each spring can act as a sort of “suspension” to absorb positional variation without admitting backlash. This can allow the interfaces to self-compensate for changing geometric and alignment errors. Diagrams of the contact angles API and AP2, for the lower and upper planet blocks 340, 342 are shown in FIG. 47. The angles in the illustrated embodiment are API = -20°, API = +15° and allow the Satellite to “clamp” itself into the planet slot 312, though different angles can be utilized in alternative embodiments. A cutaway view of the satellite orbit block 344, orbit track 314, and contact angle Ao is shown in FIG. 49. The contact angle in the illustrated embodiment is Ao = -12°, though different angles can be utilized in alternative embodiments.

[0151] In another embodiment, a vertical faces can be used for the various satellite blocks 340, 342, 344. This would decouple the lateral and axial loads from one another, but would require consideration of various aspects, such as fits and tolerances, solutions to slop / backlash, ensuring proper satellite degrees-of-freedom, etc. The taper angle for each satellite block is defined by a variable A, which corresponds to the inclination of a face’s inward-pointing normal vector from the horizontal plane: A > 0 provides positive taper, i.e., the satellite block has a “downwards taper,” is narrower at the bottom / radially-inward position relative to the planet 302, and the inward normal vector is inclined upwards / radially-outward relative to the planet. 2 = 0 provides zero taper, i.e., the satellite block has no taper, there is no narrowing, and the inward normal vector is horizontal. A < 0 provides negative taper, i.e., the satellite block has an “upwards taper,” is narrower at the top / radially-outward position relative to the planet 302, and the inward normal vector is inclined downwards / radially-inward relative to the planet.

[0152] In other embodiments, one or more faces can be employed with tapers in directions opposite those shown in the illustrated embodiments. In still other embodiments, a mix of various vertical and tapered faces can be utilized across the coupling. Moreover, opposite faces along the same tapered portion of a satellite need not have their taper angles mirrored. For example, any “right” face can have a first taper angle and a corresponding “left” face can have a second taper angle that is different from the first taper angle. In still other embodiments, satelliteblocks can utilize curved faces. For example, in the cross-sectional view of FIG. 47 the flat tapered surfaces of blocks 340, 342 that are shown as straight edges in the view of the figure could instead have a curved shape that would extend out of the plane of the page across the surface of the blocks. The same concept can also be applied to the surfaces of the block 306 that travels in the orbit ring 304.

[0153] At the core of each satellite 306 is a stepped shaft 346, machined from AISI 303 stainless steel in the illustrated embodiment, though alternative materials and manufacturing techniques can be utilized in alternative embodiments. The shaft base 352 can be a wide flange on which can sit the wave spring 348, a stack of shims 354, and the inner planet block 340. The bottoming force of the spring 348 can determine the preload force applied to the lower planet block 340. The shims 354 can allow adjustment of the shaft position so the protrusion of its shoulder 356 and thread 358 can be fine-tuned. At the end of the lower shoulder 356 sits the outer planet block 342, which engages with the shoulder 356 to support the lateral loads endured in operation. Directly backing the outer planet block 342 can be a low-profile nylon-insert locknut 360, which is tightened onto a short section of M8 x 1.25 mm thread 358, though other thread forms can be utilized in alternative embodiments. Above the locknut 360 can be the second spring 350 and a second stack of shims 362. The spring 350 can provide the orbit block preload force, but this can be sensitive to the relative position of the locknut 360 and the orbit block 344. Since the orbit block 344 will follow the orbit track 314, its exact position is subject to various associated geometric and fitment errors. The second shim stack 362 is included for this reason; it allows the spring position to be adjusted to compensate for any positional errors.

[0154] The satellite blocks can be formed from a variety of materials. For example, they can be machined from 954 aluminum-bronze, 3D printed or molded from a variety of materials, etc. In the illustrated embodiment, PETG is used to form the satellite blocks 340, 342, 344.

[0155] FIG. 41 shows a partially transparent view of the orbit block 344, including a central bore 364 formed therein to receive the shaft 346. A helix 366 can be seen wrapping around the central bore 364. The layer seam from 3D printing the orbit block 344 is recessed into the helix 366 to avoid interfering with the shaft fit. That is, the helix shape, as opposed to a vertically running seam recess, can ensure that the shaft / block interface is adequately supported from allsides. In embodiments where the blocks are formed using a different manufacturing process, such a feature may not be present.

[0156] To achieve sufficiently low sliding coefficients of friction, the planet / satellite / orbit contact surfaces can be lubricated. For example, Mobil Vactra #4 can be utilized, e.g., it can be applied manually via syringe. Mobil Vactra is a slideway oil, expressly designed to lubricate sliding bearing surfaces and to maintain consistent frictional properties (i.e., seeking to minimize stick-slip, chatter, and variation in the effective coefficient-of-friction). The #4 variant is the thickest option (grade ISO 220) in the Vactra product family, making it well suited for use on vertical and inclined surfaces where thinner oils might drain away. The use of lubrication can significantly reduce the friction in the system compared to an unlubricated state.

[0157] In other embodiments, various components of the coupling can be formed with plumbed lubricant paths where pressurized oil is pumped through the components to lubricate their contact surfaces. For example, FIG. 58 (discussed in more detail below) shows a satellite 506 configured to deliver oil out of its contact surfaces. In certain embodiments, other components can be configured to deliver oil, such as the planet track 312 or orbit track 314. And in still other embodiments, the coupling (or at least a portion thereof) can be immersed in an oil bath (continually or at regular intervals) to maintain lubrication.

[0158] An additional benefit of lubricant use is its ability to act as an agent of convective cooling. In industrial applications, for example, lubricant can be recirculated through radiators, etc., and may be able to provide significant heat dissipation capabilities that can at least equal the benefits associated with reducing friction.

[0159] FIG. 50(a)-(l) illustrates one example motion sequence of the IHC 300 with a set or deterministically controlled clutch angle (3o. Further, these photographs show IHC motion where only the orbit subassembly 303 (including orbit ring 304 and frame 332) rotates. In this example, it moves counter-clockwise relative to the figure viewpoint. The planet 302 is held stationary. The sequence shows that the satellites 306 slip through the orbit ring 304. This is a configuration and movement pattern similar to that described above and shown in FIGS. 1, 2, and 12-14.

[0160] FIG. 51 (a)— (1) illustrates another example motion sequence of the IHC 300. The clutch angle po is again set, but these photographs show IHC motion where both the planet and orbit subassemblies 301, 303 rotate in the same direction, but at different rates. The orbit subassembly 303 rotates much more quickly than the planet subassembly 301. The motion of the planet subassembly 301 is subtle, but can be seen by observing the gradual “appearance” of a planet slot 312 between FIG. 51(g) and 51(1). The relatively smaller angular movement of the planet subassembly 301 observed by marking the movement of the slot 312 in the figure sequence can be contrasted to the larger angular movement of the orbit subassembly 303 observed by marking the movement of the outer frame 332 in the figure sequence.

[0161] FIG. 52(a)-(l) illustrates another example motion sequence of the IHC 300. These photographs show IHC motion with a set clutch angle / ?o and where both the planet and orbit subassemblies 301, 303 rotate, but in opposite directions. That is, the orbit subassembly 303 can be observed to rotate counter-clockwise from the figure viewpoint, while the planet subassembly 301 can be observed to rotate clockwise from the figure viewpoint. This movement can be tracked for the planet 302 by marking the movement of any single slot 312 and / or the movement of the fastener blocks 334 formed at the end of the planet 302. This sequence demonstrates the wide variety of planet and orbit speed combinations that can be performed. Slip rate, or the difference in angular velocity between the planet subassembly 301 and the orbit subassembly 303, is the crucial speed parameter that can be adjusted using any combination of the factors described herein, including, for example, clutch angle, planet slot shape, axial position of the orbit ring center relative to the planet center, etc.

[0162] FIG. 53(a)— (1) illustrates another example motion sequence of the IHC 300. This figure includes narrow-angle photographs showing IHC motions at a deterministically controlled high clutch angle value (e.g., po = 33°). In this sequence, the lower satellite 306, first “revealed” in FIG. 53(e), traverses its planet slot 312 from right-to-left from the figure viewpoint (i.e., becoming less visible as the sequence progresses). At the same time, the upper satellite 306 above it reaches the end of its planet slot 312 and begins to reverse directions.

[0163] Pushing / ?o to extreme values, a threshold is reached at approximately 37°, wherein the coupling 300 enters a “jam” state and repeatedly drives in a hammering motion. This is themanifestation of IHC lockup, i.e., the transition to complete coupling engagement. This behavior is a sort of “soft lockup,” where input and output shafts are not strictly positively engaged. The stalling stepper motors 324, 326 repeatedly induce the aforementioned "hammering"(reminiscent of an impact driver). At the same time, the sprung satellites 306 and tapered contact surfaces mean that, with serendipitous timing, individual satellites can “sneak past” their jam positions. This allows the mechanism to advance by a fraction of a rotation before jamming again.

[0164] This “soft lockup,” as opposed to strict positive engagement, is an expected outcome, given the sprung satellites and tapered contact surfaces. This result implies that IHCs can be designed to target different lockup behaviors depending on the intended application. A “soft lockup” design similar to the illustrated embodiment could, for example, function as a torque limiter. On the other hand, when strict positive engagement is required, the use of non-sprung, non-kinematic IHCs are likely appropriate. Regardless, the successful results of lockup testing in the illustrated embodiment at (io = 37° demonstrates that IHCs can transition from variableslip operation into lockup without the need for any separate mechanisms or complications.

[0165] Further, in some embodiments treatment of the clutch angle (io as deterministically controlled can be relaxed to provide additional functionality. In terms of performing the functions of a variable-slip coupling, deterministic control of the clutch angle can be appropriate. The utility of IHCs can potentially be extended, however, by lifting this restriction. One consequence of tilting the planet track by an angle (ip is that moment loads can be developed on the orbit ring about its clutch axis, i.e., in the direction of (io modulation. If (io is not firmly set and is instead acted on by compliant elements (e.g., springs / dampers), it can potentially deliver its own mechanical feedback control.

[0166] For example, in the illustrated embodiments of FIGS. 54 and 55, the (io retaining screws 345 were released to permit the orbit ring 304 to swivel freely on its mounting pins.Then, the IHC could be operated in the usual fashion and the (io response, if any, observed. This demonstrates the capability of an IHC to function as a one-way clutch. FIG. 54(a)-(e) illustrates a motion sequence in a case with a negative slip rate (&)OP < 0) and where the planet turns at a rate lower than the orbit (a>p < mo). In such a case, (io can be self-stabilizing and will readilyreturn to center ( ?o = 0). This is true regardless of its initial position; it will readily “unlock” the coupling from even the most tightly jammed scenarios. In the example of FIG. 54, less than two complete orbit rotations returns the clutch angle [io from a larger number (FIG. 54(a)) to zero (FIG. 54(e)). In cases where the slip rate is positive (mop > 0) and [io ~ 15°, the coupling unlocks, though not as quickly as in the negative slip rate (mop < 0) case. At positive slip rates and moderate clutch angles (io (e.g., mop > 0 and (io ~ 21°) where the orbit turns at a slower rate than the planet (mo < mp), the H4C can be self-locking. That is, (io can readily diverge to its extreme values, fully engaging and locking up the coupling. FIG. 55(a)— (d) illustrates a motion sequence in such a case, where less than a full rotation of the orbit drives (io beyond the above- mentioned lockup threshold value and induces lockup of the coupling.

[0167] One-way couplings see widespread use throughout industry. Yet there has previously existed no coupling that singlehandedly achieves all three of the following behaviors: (1) oneway torque transmission, (2) positive engagement when fully locked, and (3) speedsynchronization (i.e. the ability to engage smoothly and gradually, and to transmit torque under partial slip). For example, the vast majority of existing one-way couplings (such as sprag clutches and ratcheting couplings) are dual-mode by nature; they are either fully engaged or not at all and speed synchronization must be facilitated externally. IHCs are able to realize all three of the characteristics listed above.

[0168] Alternate planet slot shapes can be employed in some embodiments to prefer or discourage coupling lockup if clutch angle is left open to variation during operation (i.e., not deterministically controlled). For example, the arc-shaped slots 112 shown in FIG. 23 can tend to drive coupling lockup or freewheeling, depending on their orientation and the direction of rotation. For example, looking to the configuration shown in FIG. 23(b), rotating the planet 102 such that the arc-shaped slot 112 at the center of FIG. 23(b) moves upward in the view of the figure can tend to maintain the satellite 106 in its position at the end of the slot 112, which can maintain the larger clutch angle and drive coupling lockup. Alternatively, if the planet 102 is rotated in the opposite direction, such that the arc-shaped slot 112 at the center of FIG. 23(b) moves downward in the view of the figure, the satellite 106 can be guided toward the middle of the slot 112. As the satellite moves toward the middle of the slot 112, the orbit ring clutch angle will return to zero and the coupling will freewheel (i.e., no torque transmission between theplanet and orbit). This phenomenon can be seen in the motion sequences of FIGS, 54 and 55 as well, because these figures involve rotation in opposite directions and the use of curved planet slots 312. In FIG. 54, the direction of rotation urges the satellite toward the middle of the planet slot 312 and the zero clutch angle, while in FIG. 55 the direction of rotation urges the satellite toward one of the terminal ends of the planet slot 312 and past the threshold clutch angle for lockup.

[0169] FIGS. 56 and 57 illustrate another embodiment of a coupling 400 according to the present disclosure that includes active control of the clutch angle (J O in operation. This is in contrast to, for example, the above-described coupling 300 that utilizes manual locking of the clutch angle using the fasteners 345. Similar to the coupling 300, the coupling 400 can include a planet 402 coupled to a first shaft 408 and an orbit ring 404 coupled to a second shaft 410. The orbit ring 410 can be coupled to an outer frame 432 that allows rotation of the orbit ring to adjust the clutch angle. In the illustrated embodiment, however, one or more actuators 409 can be coupled to the orbit ring 404 and the outer frame 432 to control the tilt angle of the orbit ring relative to the frame. In the illustrated embodiment, linear actuators 409 are mounted on opposite sides of the orbit ring / frame, though different configurations are possible in alternate embodiments. For example, in another embodiment actuation capability can be integrated into the orbit ring 404 and / or outer frame 432 rather than using a separate dedicated actuator component. Hydraulic elements, for example, can be incorporated into the orbit ring 404 and / or outer frame 432 and actuation thereof powered remotely using hydraulic channels extending thereto through the orbit ring and / or outer frame.

[0170] Returning to the embodiment of FIG. 56, an example configuration is shown in which the clutch angle is near zero, while FIG. 57 shows a configuration in which the clutch angle is larger, which can be achieved by simultaneously extending and / or retracting the illustrated linear actuators 409. In alternate embodiments, considerations related to inertia, balance, and packaging issues might lead to an alternate configuration, such as one in which the actuators are stationary and mounted remotely from the rotating subassemblies. In such a configuration, the actuators could act on the rotating orbit ring using a mechanism similar to a helicopter swashplate that utilizes, e.g., pushrods and bearing surfaces to translate stationary-mounted actuator movement to the rotating orbit ring.

[0171] FIG. 58 illustrates an alternate embodiment of a satellite 506 that includes plumbing for lubrication of the contact surfaces that interface with the planet and / or orbit ring. The satellite 506 can be similar to the satellite 306 described above, but can include one or more apertures 550 formed on the various contact surfaces of any of the lower planet block 540, upper planet block 542, and orbit block 544. The apertures can be the endpoints of passages that extend into the satellite 506. The passages can serve as reservoirs for oil or can lead to a more centrally located reservoir or reservoirs, e.g., within the shaft 546, etc. During use, oil or some other lubrication can come out of the apertures 550 and create a hydrostatic bearing effect that can facilitate movement of the satellite blocks relative to the planet and / or orbit track.

[0172] Another possible use of internal satellite plumbing can be for hydraulic adjustment of preload forces for one or more of the satellite blocks. As noted above in connection with FIG. 40, preload forces in that satellite embodiment can be controlled by springs 348, 350. An alternative embodiment can employ hydraulic pressure to provide active control of these preload forces in place of, or in addition to, the use of a spring. To do this, internal plumbing similar to that shown in FIG. 58 can be utilized to form hydraulic channels that can allow active control to either squeeze a pair of blocks together or separate them from one another, as desired. This can allow an additional method for controlling performance of the IHC.

[0173] FIG. 59 illustrates an alternate embodiment of a coupling 600 that includes a planet 602 and orbit ring 604 that are offset from one another along the shaft axis Ai. In particular, a center 652 of the planet 602 can be offset relative to a center 654 of the orbit ring 604 by a distance Di along the axis Ai. The offset can be varied based on the particular embodiment, and can extend in either direction relative to the center of the planet 652 (e.g., toward the shaft 608 extending from the planet 602 or towards the shaft 610 extending from the orbit ring 604). Also shown in the figure is the satellite 606, planet slot 612, and orbit slot 614.

[0174] FIG. 60 illustrates an alternate embodiment of a coupling 700 that includes multiple orbit rings 704a-704c surrounding a planet 702. The multiple orbit rings 704a-704c can be coupled to the shaft 710 and the planet can be coupled to the shaft 708. Each orbit ring 704a- 704c can include an orbit slot or track 714a-714c to receive one of the satellites 706a-706c. The planet 702 can include multiple slots 712a-712c to receive one of the satellites 706a-706c. Themultiple orbit rings 704a-704c can be configured to move together or independently from one another.

[0175] In the illustrated embodiment, the planet slots 712a-712c are shown as non-uniform planet curves with the upper and lower slots 712a, 712c not lying on planes that intersect the planet sphere centerline (like center slot 712b). In another embodiment, all of the planet slots 712a-712c can be meridional with planes that intersect the planet sphere centerline. In such an embodiment, the upper and lower slots 712a, 712c in the view of FIG. 60 would appear curved rather than straight.

[0176] Still further, while the illustrated embodiment of FIG. 60 shows a one-to-one relationship of slots-to-satellites where each satellite travels in its own planet slot, alternative configurations are possible. For example, in some embodiments more than one satellite can travel through a single planet slot, so long as the satellites cannot collide with one another.

[0177] While the above-described embodiments of FIGS. 26-58 illustrate a satellite 306 having three blocks, alternative configurations are also possible and within the scope of the present disclosure. For example, FIG. 61 illustrates an example embodiment of a “two block” satellite 806. In one embodiment, the satellite 806 includes a planet block 842 and an orbit block 844 with a pin or shaft 846 extending therebetween. Each of the planet block 842 and orbit block 844 can ride within a rectangular channel of the planet and orbit, respectively, with the top and bottom surfaces of those channels providing radial motion constraints. The channels can have sufficient tolerances to provide smooth slip-fit clearance without binding, etc. Further, while rectangular block and corresponding channel shape is noted here, any of a variety of alternatives are also possible, including any of the various tapered, curved, or other shapes described above. Further, any of the above-noted additional satellite features, such as lubrication and / or internal plumbing related to same, can be integrated into a “two block” satellite embodiment.

[0178] In still other embodiments, a ball bearing or series thereof can be utilized as a satellite component. For example, the various slots of the planet and / or orbit can have a variety of geometries, such as v-grooves, semicircles, etc., and the ball bearings can ride therein.

[0179] In certain embodiments, one or more couplings can be assembled together and each coupling can utilize differently shaped components. For example, a coupling can utilize multiple planet shapes in a single mechanism (e.g., spherical or otherwise, etc.), and / or multiple planet slots shapes (e.g., straight, curved, etc.). The use of alternating planet shapes and / or planet slot shapes can provide an approach for mitigating torque ripple.

[0180] The above-described couplings and components thereof can be constructed from any of a variety of known materials. Example materials include any of a variety of metals, polymers, ceramics, and composites, including combinations thereof where different components are formed from different materials. Some more specific example materials are described above. The various components of the devices disclosed herein can be rigid or flexible, or have different levels of rigidity or flexibility depending on a particular embodiment and / or desired function. In addition, one or more of the components or devices disclosed herein can be formed as monolithic or unitary structures, e.g., formed from a single continuous material, or can be formed from separate components coupled together in a variety of manners that either facilitate or discourage subsequent separation. Further, various methods of manufacturing can be utilized, including 3D printing or other additive manufacturing techniques, as well as more conventional manufacturing techniques, including molding, stamping, casting, machining, etc.

[0181] In this disclosure, phrases such as “at least one of’ or “one or more of’ may occur followed by a conjunctive list of elements or features. By way of example, “an element” means at least one element and can include more than one element. The term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “slightly above” or “slightly below” the endpoint without affecting the desired result. The use herein of the terms “including,” “comprising,” or “having,” and variations thereof, is meant to encompass the elements listed thereafter and equivalents thereof, as well as additional elements. As used herein, “and / or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations where interpreted in the alternative (“or”). Further, phrases such as “at least one of’ or “one or more of’ may occur followed by a conjunctive list of elements or features. The term “and / or” may also occur in a list of two or more elements or features. Unless otherwise implicitly or explicitly contradicted by the context in which it is used, such a phrase is intended to mean any of the listed elements orfeatures individually or any of the recited elements or features in combination with any of the other recited elements or features. For example, the phrases “at least one of A and B,” “one or more of A and B,” and “A and / or B” are each intended to mean “A alone, B alone, or A and B together.” A similar interpretation is also intended for lists including three or more items. For example, the phrases “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, and / or C” are each intended to mean “A alone, B alone, C alone, A and B together, A and C together, B and C together, or A and B and C together.” In addition, use of the term “based on,” is intended to mean, “based at least in part on,” such that an un-recited feature or element is also permissible.

[0182] To the extent that linear, circular, or other dimensions are used in the description of the disclosed devices and methods, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such devices and methods. Equivalents to such dimensions can be determined for different geometric shapes, etc. Further, like-numbered components of the embodiments can generally have similar features. Still further, sizes and shapes of the devices, and the components thereof, can depend at least on the size and shape of objects with which the devices will be used, and the methods in which the devices will be used.

[0183] The figures provided herein are not necessarily to scale. Still further, to the extent arrows are used to describe a direction of movement, these arrows are illustrative and in no way limit the direction that the respective component can or should be moved. Other movements and directions may be possible to create the desired result in view of the present disclosure.

[0184] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if a concentration range is stated as 1% to 50%, it is intended that values such as 2% to 40%, 10% to 30%, or 1% to 3%, etc., are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this disclosure.

[0185] Further features and advantages based on the above-described embodiments are possible and within the scope of the present disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described. All publications and references cited herein are expressly incorporated herein by reference in their entirety, except for any definitions, subject matter disclaimers, or disavowals, and except to the extent that the incorporated material is inconsistent with the express disclosure herein, in which case the language in this disclosure controls.

[0186] Examples of the above-described embodiments can include the following:1. A coupling, comprising: a rigid planet coupled to a first shaft and having a first slot formed therein; a rigid orbit ring coupled to a second shaft and having a second slot formed therein, the orbit ring being disposed around the planet; and a rigid satellite with a first end disposed within the first slot of the planet and a second end disposed within the second slot of the orbit ring; wherein the coupling is configured to selectively transfer torque between the first shaft and the second shaft via normal and frictional force interactions between the satellite and each of the planet and the orbit ring.2. The coupling of example 1, wherein the first slot extends parallel to a longitudinal axis of the first shaft.3. The coupling of example 1, wherein the first slot is curved relative to a longitudinal axis of the first shaft.4. The coupling of any of examples 1 to 3, wherein a longitudinal axis of the satellite intersects a center of the planet.5. The coupling of any of examples 1 to 4, wherein the planet is spherical.6. The coupling of any of examples 1 to 5, wherein the second slot is formed along an inner circumference of the orbit ring.7. The coupling of any of examples 1 to 6, wherein the first shaft and the second shaft are coaxial.8. The coupling of any of examples 1 to 7, wherein the first shaft extends in a first direction from the planet and the second shaft extends in a second direction from the orbit ring that is different from the first direction.9. The coupling of any of examples 1 to 8, wherein the orbit ring is configured to rotate about an orbit tilt axis that is perpendicular to a longitudinal axis of the second shaft.10. The coupling of example 9, further comprising an actuator coupled to the orbit ring and configured to control rotation of the orbit ring about the orbit tilt axis.11. The coupling of any of examples 9 to 10, wherein the orbit ring is configured to rotate through an angular range of about 45 degrees in either direction from a first position in which the orbit ring defines a plane that is perpendicular to a longitudinal axis of the first shaft.12. The coupling of any of examples 9 to 11, wherein the coupling is configured to transfer torque between the first shaft and the second shaft with continuous slip over time based on an angle of rotation of the orbit ring about the orbit tilt axis.13. The coupling of any of examples 1 to 11, wherein the planet has a plurality of slots formed therein.14. The coupling of any of examples 1 to 12, further comprising a plurality of satellites.15. The coupling of any of examples 1 to 13, wherein the satellite further comprises: a shaft; a lower block disposed around the shaft and configured to contact a radially-inner portion of the planet; an upper block disposed around the shaft and configured to contact a radially- outer portion of the planet; andan orbit block disposed around the shaft and configured to ride within the second slot of the orbit ring.16. The coupling of example 14, wherein one or more of the lower block, upper block, and orbit block include an aperture for delivering lubrication to a surface in contact with another component of the coupling.17. The coupling of any of examples 1 to 15, wherein a center of the orbit ring is offset from a center of the planet along a longitudinal axis of the first shaft.18. The coupling of any of examples 1 to 16, further comprising one or more additional orbit rings disposed around the planet and offset from the orbit ring along a longitudinal axis of the first shaft.19. The coupling of example 17, wherein the one or more additional orbit rings move together with the orbit ring.20. The coupling of example 17, wherein the one or more additional orbit rings move independently from the orbit ring.21. A method, comprising: rotating a first shaft extending from a coupling that includes a rigid planet, a rigid orbit ring disposed around the planet, and a rigid satellite riding in both a first slot formed in the planet and a second slot formed in the orbit ring; selectively transferring torque between the first shaft and a second shaft extending from the coupling via normal and frictional force interactions between the satellite and each of the planet and the orbit ring.22. The method of example 21, further comprising adjusting an angle of the orbit ring about an axis that is perpendicular to an axis of rotation of the first shaft to vary an amount of continuous slip over time and thereby an amount of torque transferred between the first shaft and the second shaft.23. The method of example 22, wherein the angle of the orbit ring is adjusted using an actuator coupled to the orbit ring.24. The method of any of examples 21 to 23, further comprising lubricating an interface between the satellite and one or more of the planet and the orbit ring.25. The method of any of examples 21 to 24, wherein no torque is transferred between the first shaft and the second shaft.26. The method of any of examples 21 to 24, wherein the first shaft and the second shaft rotate at a single speed.27. The method of any of examples 21 to 24, wherein the first shaft rotates at a first speed that is greater than a second speed of the second shaft.28. The method of any of examples 21 to 24, wherein the first shaft rotates at a first speed that is less than a second speed of the second shaft.29. The method of any of examples 21 to 24, wherein the first shaft and the second shaft rotate in the same direction.30. The method of any of examples 21 to 24, wherein the first shaft rotates in a first direction and the second shaft rotates in a second direction that is opposite the first direction.31. The method of any of examples 21 to 24, further comprising adjusting the selective transfer of torque between the first shaft and the second shaft based on an amount of torque detected on the first shaft.32. The method of any of examples 21 to 24, further comprising adjusting the selective transfer of torque between the first shaft and the second shaft based on an amount of torque detected on the second shaft.

Claims

CLAIMSWhat is claimed is:

1. A coupling, comprising: a rigid planet coupled to a first shaft and having a first slot formed therein; a rigid orbit ring coupled to a second shaft and having a second slot formed therein, the orbit ring being disposed around the planet; and a rigid satellite with a first end disposed within the first slot of the planet and a second end disposed within the second slot of the orbit ring; wherein the coupling is configured to selectively transfer torque between the first shaft and the second shaft via normal and frictional force interactions between the satellite and each of the planet and the orbit ring.

2. The coupling of claim 1, wherein the first slot extends parallel to a longitudinal axis of the first shaft.

3. The coupling of claim 1, wherein the first slot is curved relative to a longitudinal axis of the first shaft.

4. The coupling of claim 1, wherein a longitudinal axis of the satellite intersects a center of the planet.

5. The coupling of claim 1, wherein the planet is spherical.

6. The coupling of claim 1, wherein the second slot is formed along an inner circumference of the orbit ring.

7. The coupling of claim 1, wherein the first shaft and the second shaft are coaxial.

8. The coupling of claim 1, wherein the first shaft extends in a first direction from the planet and the second shaft extends in a second direction from the orbit ring that is different from the first direction.

9. The coupling of claim 1, wherein the orbit ring is configured to rotate about an orbit tilt axis that is perpendicular to a longitudinal axis of the second shaft.

10. The coupling of claim 9, further comprising an actuator coupled to the orbit ring and configured to control rotation of the orbit ring about the orbit tilt axis.

11. The coupling of claim 9, wherein the orbit ring is configured to rotate through an angular range of about 45 degrees in either direction from a first position in which the orbit ring defines a plane that is perpendicular to a longitudinal axis of the first shaft.

12. The coupling of claim 9, wherein the coupling is configured to transfer torque between the first shaft and the second shaft with continuous slip over time based on an angle of rotation of the orbit ring about the orbit tilt axis.

13. The coupling of claim 1, wherein the planet has a plurality of slots formed therein.

14. The coupling of claim 1, further comprising a plurality of satellites.

15. The coupling of claim 1, wherein the satellite further comprises: a shaft; a lower block disposed around the shaft and configured to contact a radially-inner portion of the planet; an upper block disposed around the shaft and configured to contact a radially-outer portion of the planet; and an orbit block disposed around the shaft and configured to ride within the second slot of the orbit ring.

16. The coupling of claim 14, wherein one or more of the lower block, upper block, and orbit block include an aperture for delivering lubrication to a surface in contact with another component of the coupling.

17. The coupling of claim 1, wherein a center of the orbit ring is offset from a center of the planet along a longitudinal axis of the first shaft.

18. The coupling of claim 1, further comprising one or more additional orbit rings disposed around the planet and offset from the orbit ring along a longitudinal axis of the first shaft.

19. The coupling of claim 17, wherein the one or more additional orbit rings move together with the orbit ring.

20. The coupling of claim 17, wherein the one or more additional orbit rings move independently from the orbit ring.

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