Electromagnetically-Controlled Magnetic Cycloidal Gear Assembly for Achieving Enhanced Torque Capacity and Method of Operating Same

The present disclosure relates to electromagnetically-controlled magnetic cycloidal gear assemblies configured to achieve enhanced torque capacity, and methods of operating same. In one example embodiment, a method includes sensing a position of a cycloid relative to a stator, where the stator includes a plurality of electromagnets, and the cycloid includes a plurality of permanent magnets. Also, the method includes determining respective torque characteristics concerning the respective electromagnets based upon the sensed position, where the respective torque characteristic that is determined concerning each respective one of the electromagnets is indicative of a respective relative position of the respective electromagnet in relation to a respective closest one of the permanent magnets. The method additionally includes outputting from a controller, for receipt respectively at least indirectly by the respective electromagnets or respective control devices coupled thereto, a plurality of output signals respectively based at least in part upon the respective torque characteristics.

CROSS-REFERENCE TO RELATED APPLICATIONS

Field of the Invention

The present invention relates to gearboxes or gear assemblies or systems, and more particularly to magnetic cycloidal gearboxes or gear assemblies or systems, and methods of operating same, in which the gearboxes, gear assemblies, systems, or methods are configured to achieve enhanced torque capacity.

Background of the Invention

Gear assemblies are used in a wide variety of applications in order to transmit speed and torque from rotating power sources to other devices. Often, a gear assembly operates to communicate, for receipt by another device, output speed and output torque that are different from input speed and input torque that are received from a rotating power source. Various mechanical and magnetic gear assemblies are known. One type of known magnetic gear assembly is the magnetic cycloidal gear assembly.

The general principle of a magnetic cycloidal gear assembly can be understood to involve two circular structures of unequal size, with the larger circular structure being stationary, and with the smaller circular structure being positioned within the interior of the larger circular structure and arranged to be tangent (or substantially tangent) to an interior circular edge of the larger circular structure. Given such an arrangement, the smaller circular structure can be configured to rotate within the inside of the larger circular structure, along the interior circular edge, in an eccentric manner. Such rotational motion can be exploited for gearing when the outer, larger circular structure is a stator and the inner, smaller circular structure is a rotor.

More particularly,FIG.1Ais a schematic, front elevation view of a conventional magnetic cycloid gear10, having a stator12and a rotor14. The stator12and rotor14are positioned in an eccentric (or non-concentric) manner, such that a rotor axis20is displaced with respect to and not aligned with a stator axis22. An input drive shaft (not shown) that drives the rotor14has a central axis that is aligned with the stator axis22, such that the rotor axis20also is displaced with respect to the central axis of the input drive shaft. Although the rotor axis20is displaced from the central axis of the input drive shaft, the input drive shaft nevertheless is engaged with the rotor14in a manner (e.g., by way of a cam) such that rotation of the input drive shaft causes corresponding rotation of the rotor axis20about the stator axis22, such that the rotor axis20follows a trajectory T (shown in the dashed lines).

Although rotation of the input drive shaft causes rotation of the rotor axis20about the stator axis22that occurs at the same rotational frequency as the rotation of the input drive shaft itself, this is not to say that the entire rotor14rotates at that frequency. Rather, magnetic pole pairs16are arrayed on the stator12and rotor14, and magnetic interactions between those of the magnetic pole pairs of the stator12and rotor14that are closest together depending upon the relative positioning of the stator and rotor at any given time, prevent relative “slipping” motion between the stator and rotor. Thus, as governed by the interaction of the magnetic pole pairs16, rotation of the input drive shaft causes an outer circular edge24of the rotor14to “roll along” an inner circular edge18of the stator12(with those edges only being separated by an air gap), in an eccentric manner determined by the rotation of the rotor axis20about the stator axis22.

The amount of rotation that is experienced by the rotor14relative to the stator12(as the outer circular edge24of the rotor rolls along the inner circular edge18of the stator) is determined by the difference in the number of pole pairs arranged along the inner circular edge of the stator relative to the number of pole pairs arranged along the outer circular edge of the rotor. In general, because the stator12has more pole pairs along the inner circular edge18than the rotor14has along the outer circular edge24, the rotor14will rotate more than a full revolution for every revolution it travels around the stator12. The gear ratio is based on the number of pole pairs arrayed on the stator as compared to the number of pole pairs arrayed on the rotor. For example, if the stator has m+1pole pairs, and the rotor has m pole pairs, then the gear ratio between the two is -1/m. In the embodiment ofFIG.1A, the gear ratio also effectively corresponds to the difference in the circumferences between the inner circular edge18and the outer circular edge24because magnets of the same size are employed on each of the stator12and the rotor14. But this is not fundamental and, in other embodiments (e.g., embodiments in which the magnets employed on the stator are sized differently than the magnets employed on the rotor), the gear ratio need not correspond particularly to the difference in the circumferences between the inner circular edge of the stator and the outer circular edge of the rotor.

In a magnetic cycloidal gear assembly, the rotor14is mounted on (or is formed by) a cycloidal disk. Although not shown inFIG.1A, it should be appreciated that the cycloidal disk, in addition to being mounted eccentrically on the input shaft as described, is typically coupled to an output structure, which serves to output rotational power from the magnetic cycloidal gear assembly. The output rotational torque and speed provided by the output structure typically differ respectively from the input rotational torque and speed (received via the input shaft) in accordance with the gear ratio established by the pole pairs16of the rotor14and the stator12.

Notwithstanding the existence of conventional magnetic cycloidal gear assemblies, such conventional magnetic cycloidal gear assemblies face certain challenges and concerns. Magnetic cycloidal gears assemblies often require large external diameters to achieve the same torque carrying capacity of equivalent mechanical gears (spur, planetary etc.). As such, to act as a direct replacement for mechanical gearboxes in actuation systems, space accommodations must be made, such as increasing the physical envelope or removing other features. Although such accommodations may be possible, such accommodations can involve tradeoffs that result in the loss of features or functions that are desirable.

For example, in the Integrated Servo Actuator and Controller (ISAAC) available from Kaney Aerospace, Inc. of Rockford, IL, the disengage clutch has been removed to accommodate the magnetic gearbox. Yet removal of the disengage clutch is not preferable. If the disengage clutch were present, the disengage clutch would allow the actuator output to fully disengage and freewheel in certain operational circumstances, such as in the case of a manual override. Additionally, although the magnetic cycloidal gearbox can be back-driven when the motor is unpowered, the back-drive torque is significantly higher than the free-wheel torque that would arise during freewheeling if the disengage clutch were present. This correspondingly can increase the likelihood that the actuator may jam in a manner that is not easily overridden through manual intervention or by way of a parallel actuator, which may be undesirable in some aerospace applications.

Also, because of the difference in pole pairs between the rotor and stator (e.g., one pole pair between the rotor and stator in the example discussed above), the polarity of adjacent poles is necessarily shifted for the point of maximum airgap relative to the point of minimum airgap. Thus, when the rotor is aligned such that the polarity of adjacent poles of the rotor and stator is common at the point of minimum airgap, the polarity of adjacent poles of the rotor and stator at the point of maximum airgap are in direct opposition. Additionally, as the rotor moves to take up torque, the poles at the minimum airgap will attract each other and the poles at the maximum airgap will repel one another, albeit at a lower force due to the larger air gap. Further, if one considers the magnetic interactions among all of the opposed magnets of the rotor and stator, it will be appreciated that a significant subset of the magnets of the rotor and stator will be acting to repel one another tangentially. Because of such tangential repelling actions, such magnets of the rotor and stator contribute negatively to the overall torque carrying capacity of the rotor.

Such magnetic interactions and consequent effects are illustrated additionally byFIGS.1B,1C, and1D, which show portions of a conventional magnetic cycloidal gear assembly50. Similar to the magnetic cycloid gear10ofFIG.1A, the conventional magnetic cycloidal gear assembly50includes both a stator52and a rotor (or cycloid)54. Additionally, the conventional magnetic cycloidal gear assembly50ofFIGS.1B,1C, and1Dalso includes magnetic pole pairs56as well as an input shaft58having an offset cam60, which is positioned within and supports the rotor (or cycloid)54by way of a rolling element bearing62. Although not shown, it should be appreciated that the input shaft58and stator52are both concentric about a stator axis (not shown), but that the offset cam60is offset with respect to the stator axis. Also, although not shown, the conventional magnetic cycloidal gear assembly50includes an output structure by which the gear assembly (and the rotor54thereof) serves to output rotational power to a load.

In the present example ofFIGS.1B,1C, and1D, the stator52particularly includes a back-iron cylinder64and m permanent magnets66(where, in this example, m=26) that are mounted within the back-iron cylinder and positioned along an inner cylindrical surface68of the back-iron cylinder. Each of the permanent magnets66is positioned between a respective pair of teeth70of the back-iron cylinder64, and face inwardly towards the stator axis (that is, the central axis) of the stator52. Additionally, the rotor54includes a back-iron cylinder (or disk)74and n permanent magnets76(where, in this example, n=m-1=25) mounted within the back-iron cylinder and positioned along an outer cylindrical surface78of the back-iron cylinder. Each of the permanent magnets76is positioned between a respective pair of teeth80of the back-iron cylinder74, and face outwardly toward the stator52.

Also in this regard,FIG.1Bincludes a plurality of outwardly-directed arrows72that are respectively representative of magnetic flux passing through and out of the permanent magnets66of the stator52. Further,FIG.1Cincludes a plurality of outwardly-directed arrows82that are respectively representative of magnetic flux passing through and out of the permanent magnets76of the rotor54. In general, the arrows72are radially-outwardly directed away from the stator axis (e.g., the central axis) of the stator52, and the arrows82are radially-outwardly directed away from a rotor axis (e.g., a central axis of the rotor54), given the positioning of the permanent magnets66and76, respectively. Further, it should be appreciated that, although each of the arrows72and82inFIGS.1B and1Cis outwardly directed, the magnetic flux emanating from each of the respective permanent magnets66and76generally follows looping paths around each respective permanent magnet as the magnetic flux exits each respective permanent magnet. That is (although not shown), after exiting each of the permanent magnets66and76, the flux then loops back inwardly through the respective teeth70and80between the respective permanent magnet and respective neighboring ones of the permanent magnets, and then further loops back in an outwardly-directed manner so as to re-enter the respective permanent magnet.

Given the manner in which magnetic flux passes out of, around, and into the various ones of the permanent magnets66and76, it should be recognized that (as noted above) the magnetic flux of the permanent magnets66and the magnetic flux of the permanent magnets76is aligned for those ones of the permanent magnets that are at or near a first region84of minimum airgap (e.g., near the top of the stator52as shown inFIGS.1B and1C). However, the magnetic flux of the permanent magnets66and the magnetic flux of the permanent magnets76is out of alignment for those ones of the permanent magnets that are at or near a second region86of maximum airgap (e.g., near the bottom of the stator52as shown inFIGS.1B and1C). Thus, poles at the minimum airgap will attract each other and the poles at the maximum airgap will repel one another, albeit at a lower force due to the larger air gap.

Referring additionally toFIG.1D, it will be appreciated that in this circumstance the rotor54has a slightly different position relative to the stator52than is illustrated byFIGS.1B and1C. More particularly, it can be seen that the rotor54has a rotational position that is rotated slightly in a clockwise manner, in a direction indicated by an arrow90, relative to the stator52, by comparison with the rotational position of the rotor54relative to the stator52shown inFIGS.1B and1C. Such rotational positioning of the rotor54relative to the stator52can occur particularly if the magnetic cycloidal gear assembly50—and the rotor54, due to force/torque applied via the output structure of the gear assembly, which is not shown—is under load.

FIG.1Dparticularly also shows arrows92that illustrate example magnetic forces that are experienced between respective ones of the permanent magnets76of the rotor54and nearby respective ones of the permanent magnets66of the stator52when the rotor54and the stator52are positioned relative to one another in the manner shown. The arrows92illustrate how, due to the permanent magnets66on the stator52being larger in number than the permanent magnets76on the rotor54(due to there being a larger number of the pole pairs56on the stator52than on the rotor54), different pairs of proximate ones of the permanent magnets66and permanent magnets76experience magnetic forces that are oppositely-directed in terms of whether those forces tend to cause torquing of the rotor54relative to the stator52in a rotational direction corresponding to or counter to that of the arrow90. It should be appreciated that, although the arrows92illustrate magnetic forces that are the strongest (or primary) magnetic forces in that those forces are experienced between each respective one of the permanent magnets76and the respective one(s) of the permanent magnets66that are closest to one another, there are also less strong (or secondary) magnetic forces (not represented by the arrows92) that can be experienced between various pairs of the magnets76and66that are not closest to one another.

More particularly, it can be seen fromFIG.1Dthat the arrows92linking any of first ones94of the permanent magnets76of the rotor54to closest neighboring ones of the permanent magnets66of the stator52have directions with a component tending to be rotationally aligned with the rotational direction of the arrow90. This is because the closest neighboring ones of the permanent magnets66of the stator52relative to each of those first ones94of the permanent magnets76happen to be positioned clockwise relative to the respective positions of those permanent magnets76. In contrast, the arrows92linking any of second ones96of the permanent magnets76of the rotor54to closest neighboring ones of the permanent magnets66of the stator52have directions with a component tending to be opposed to the rotational direction of the arrow90. This is because the closest neighboring ones of the permanent magnets66of the stator52relative to each of those second ones96of the permanent magnets76happen to be positioned counter-clockwise relative to the respective positions of those permanent magnets76. It will be further appreciated that, in some cases, it is possible that a given one of the permanent magnets76of the rotor54will be positioned equally closely to each of a pair of the permanent magnets66of the stator52(or vice-versa). In such a case, as represented for example by a bidirectional arrow88(pair of arrows) linking a further one98of the permanent magnets76of the rotor54with two of the permanent magnets66of the stator, the forces imposed upon the rotor54will equally tend to cause torquing of the rotor in a direction aligned with, or opposed to, the rotational direction of the arrow90.

The arrows92ofFIG.1Dillustrate how the magnetic forces occurring between different pairs of the permanent magnets66and76of the stator52and rotor54can diminish the torque carrying capacity of the magnetic cycloidal gear assembly50and the rotor54thereof. Indeed, it should be recognized that it is primarily the torque arising from the forces between the second ones96of the permanent magnets76and those of the permanent magnets66closest thereto that can be delivered to a load by the conventional magnetic cycloidal gear assembly50(or the rotor54thereof). In contrast, the torque arising from the forces between the first ones94of the permanent magnets76and those of the permanent magnets66closest thereto tend to counteract and diminish that deliverable torque. (Also, with respect to the forces occurring between two of the stator permanent magnets66and a single one of the rotor permanent magnets76that is equally close to those two stator permanent magnets, or vice-versa, such as the forces described above involving the further one98of the permanent magnets76, there is no significant impact upon deliverable torque by those forces.) In effect, the torque arising from the primary forces generated by the first ones94of the permanent magnets76serves to repel or counteract some of the torque arising from the primary forces generated by the second ones96of the permanent magnets76, thus reducing overall torque carrying capacity of the magnetic cycloidal gear assembly50(and the rotor54thereof).

For at least one or more of these reasons, or one or more other reasons, it would be advantageous if new or improved magnetic cycloidal gear boxes, gear assemblies or systems could be developed, and/or improved methods of operation of such gearboxes, assemblies or systems could be developed, so as to address any one or more of the concerns discussed above or to address one or more other concerns or provide one or more benefits.

SUMMARY

In at least one example embodiment, the present disclosure relates to an electromagnetically-controlled magnetic cycloidal gear assembly. The magnetic cycloidal gear assembly includes a stator that is fixed and concentric with respect to a primary axis of the magnetic cycloidal gear assembly, and that includes a plurality of first magnetic devices, and also includes an input shaft that is configured to rotate about the primary axis and that includes an offset cam that is offset with respect to the primary axis. Additionally, the magnetic cycloidal gear assembly also includes a cycloid mounted at least indirectly upon the offset cam and configured to rotate both relative to the offset cam and also within the stator, where the cycloid is eccentric with respect to the primary axis and includes a plurality of second magnetic devices. Further, the magnetic cycloidal gear assembly additionally includes an output hub that is concentric with the primary axis and includes a plurality of cam follower receivers, and a plurality of cam followers, each cam follower having a respective first end and a respective second end, where the respective first end of each cam follower is received within a respective one of the cam follower receivers and the respective second end of each cam follower is coupled to the cycloid at a respective location on the cycloid. Additionally, either each of the first magnetic devices or each of the second magnetic devices includes a respective electromagnet configured to produce a respective magnetic field in accordance with a respective current passing therethrough.

Further, in at least one example embodiment, the present disclosure relates to an electromagnetically-controlled magnetic cycloidal gear assembly. The magnetic cycloidal gear assembly includes a stator that is fixed and concentric with respect to a primary axis of the magnetic cycloidal gear assembly, and that includes a plurality of first magnetic devices, where each of the first magnetic devices includes a respective electromagnet. Also, the magnetic cycloidal gear assembly includes an input shaft that is configured to rotate about the primary axis and that includes an offset cam that is offset with respect to the primary axis. Further, the magnetic cycloidal gear assembly additionally includes a cycloid mounted at least indirectly upon the offset cam and configured to rotate both relative to the offset cam and also within the stator, where the cycloid is eccentric with respect to the primary axis and includes a plurality of second magnetic devices, and where each of the second magnetic devices includes a respective permanent magnet. Additionally, the magnetic cycloidal gear assembly also includes an output hub that is concentric with the primary axis and includes a plurality of cam follower receivers, where the output hub is at least indirectly rotationally coupled to the cycloid by way of a plurality of cam followers that are coupled to the cycloid and that respectively interface the cam follower receivers. Further, the magnetic cycloidal gear assembly additionally includes a controller coupled to each of the electromagnets by way of one or more linkages, where the controller is configured to govern at least one electric current that is passed through at least one of the electromagnets so as to produce a magnetic field.

Additionally, in at least one example embodiment, the present disclosure relates to a method of operating a electromagnetically-controlled magnetic cycloidal gear assembly. The method includes providing a stator that is fixed and concentric with respect to a primary axis of the magnetic cycloidal gear assembly, and that includes a plurality of first magnetic devices, where each of the first magnetic devices includes a respective electromagnet. Also, the method includes causing, at least indirectly by way of a controller, at least one current to flow through the respective electromagnets of the first magnetic devices so as to generate a magnetic field. Additionally, the method includes receiving input rotational power at an input shaft having an offset cam about the primary axis, where the offset cam is offset with respect to the primary axis. Further, the method includes, in response to the receiving of the input rotational power, eccentrically rotating a cycloid that is mounted at least indirectly upon the offset cam within the stator, where the cycloid is eccentric with respect to the primary axis and includes a plurality of second magnetic devices, and where each of the second magnetic devices includes a respective permanent magnet. The cycloid eccentrically rotates at least in part due to interactions between the first magnetic devices and the second magnetic devices. Additionally, the method also includes communicating at least one first portion of the input rotational power from the cycloid to an output hub that is concentric with the primary axis and includes a plurality of cam follower receivers, by way of a plurality of cam followers that are coupled to the cycloid and that interface the cam follower receivers, and outputting the at least one first portion of the input rotational power as output rotational power from the output hub.

Further, in at least one additional example embodiment, the present disclosure relates to an electromagnetically-controlled magnetic cycloidal gear assembly that is configured to achieve an enhanced torque capacity. The electromagnetically-controlled magnetic cycloidal gear assembly includes a stator, an input shaft, a cycloid, an output hub, and a controller. The stator is fixed and concentric with respect to a primary axis of the magnetic cycloidal gear assembly, and includes a plurality of electromagnets, and the input shaft is configured to rotate about the primary axis and includes an offset cam that is offset with respect to the primary axis. The cycloid is mounted at least indirectly upon the offset cam and configured to rotate both relative to the offset cam and also within the stator, where the cycloid is eccentric with respect to the primary axis and includes a plurality of permanent magnets, and the output hub is concentric with the primary axis and coupled at least indirectly to the cycloid so that output torque and speed can be at least indirectly communicated to the output hub from the cycloid. The controller is coupled at least indirectly to the electromagnets or coupled at least indirectly to a plurality of control devices that respectively are coupled to the electromagnets, respectively. At a first time, the controller operates (a) to generate at least one first output signal that is configured to cause each of a first subset of the electromagnets to produce a respective first magnetic flux with a first polarity, and (b) either to generate at least one second output signal that is configured to cause each of a second subset of the electromagnets to produce a respective second magnetic flux with a second polarity that is opposite to the first polarity or that is configured to cause each of the second subset of the electromagnets to be switched off, or to refrain from generating the at least one second output signal so that each of the second subset of the electromagnets is switched off.

Additionally, in at least one further example embodiment, the present disclosure relates to an electromagnetically-controlled magnetic cycloidal gear assembly that is configured to achieve an enhanced torque capacity. The electromagnetically-controlled magnetic cycloidal gear assembly includes an input shaft and an output shaft, where the input shaft includes an offset cam, a stator, and a cycloid. The stator is fixed and concentric with respect to a primary axis of the magnetic cycloidal gear assembly, and the cycloid is mounted at least indirectly upon the offset cam, configured to rotate both relative to the offset cam and also within the stator, and coupled at least indirectly to the cycloid so that output torque can be at least indirectly communicated to the output shaft. The electromagnetically-controlled magnetic cycloidal gear assembly also includes a plurality of electromagnets supported upon a first one of the stator and cycloid, and a plurality of permanent magnets supported upon a second one of the stator and cycloid. Further, the electromagnetically-controlled magnetic cycloidal gear assembly includes a controller coupled at least indirectly to the electromagnets or coupled at least indirectly to a plurality of control devices that respectively are coupled to the electromagnets. The controller is configured to determine, at a plurality of times on a repeated or continual basis, respective torque characteristics concerning the respective electromagnets. The respective torque characteristic that is determined concerning each respective one of the electromagnets at a first one of the times is indicative of a respective relative position of the respective one of the electromagnets in relation to a respective closest one of the permanent magnets at or proximate to the first one of the times. Additionally, the controller is configured to output a plurality of output signals at the plurality of times for receipt, respectively, by respective ones of the electromagnets or respective ones of the switching devices, where the plurality of output signals control or influence respective actuation statuses of the respective electromagnets. Also, the output signals that are output by the controller at or proximate to the first one of the times are generated based at least in part upon the respective torque characteristics determined at the first one of the times, and are configured to cause a first subset of the electromagnets to produce respective first magnetic fluxes having a first polarity, and to cause a second subset of the electromagnets to either be deactivated or to produce respective second magnetic fluxes having a second polarity.

Further, in at least one additional example embodiment, the present disclosure relates to a method of operating an electromagnetically-controlled magnetic cycloidal gear assembly to achieve an enhanced torque capacity. The method includes sensing a position of a cycloid relative to a stator, where the stator is concentric with respect to a primary axis and includes a plurality of electromagnets, and where the cycloid is mounted at least indirectly upon an offset cam of an input shaft, is configured to rotate both relative to the offset cam and also within the stator, and includes a plurality of permanent magnets. The method also includes determining at a first time respective torque characteristics concerning the respective electromagnets based at least in part upon the sensed position, where the respective torque characteristic that is determined concerning each respective one of the electromagnets at the first time is indicative of a respective relative position of the respective one of the electromagnets in relation to a respective closest one of the permanent magnets. The method additionally includes outputting from a controller, for receipt respectively at least indirectly by the respective electromagnets or respective control devices coupled to the respective electromagnets, a plurality of output signals, where the plurality of output signals are respectively based at least in part upon the respective torque characteristics, and where the plurality of output signals at least indirectly control or influence whether the respective electromagnets are energized or not energized, or control or influence whether respective currents conducted by the respective electromagnets when energized have a positive polarity or a negative polarity, respectively. The plurality of output signals includes one or more first output signals that is or are output for receipt by a first subset of the electromagnets or by a first subset of the respective control devices coupled to the electromagnets of the first subset, where the one or more first output signals are configured to cause the electromagnets of the first subset to be energized and to cause the respective currents conducted by the respective electromagnets of the first subset to have a positive polarity. Further, either (a) the electromagnets of a second subset of the electromagnets are not energized when the electromagnets of the first subset are energized, or (b) the plurality of output signals includes one or more second output signals that is or are output for receipt by the second subset of the electromagnets or by a second subset of the respective control devices, where the one or more second output signals are configured to cause the electromagnets of the second subset to be energized and to cause the respective currents conducted by the respective electromagnets of the second subset to have a negative polarity.

Notwithstanding the above examples, the present invention is intended to encompass a variety of other embodiments including for example other embodiments as are described in further detail below as well as other embodiments that are within the scope of the claims set forth herein.

DETAILED DESCRIPTION

The present disclosure relates to embodiments of magnetic cycloidal (or cycloid) gear assemblies or systems, which can also be referred to as magnetic gearboxes, that employ electromagnets in place of at least some permanent magnets that might otherwise be employed in conventional magnetic gearboxes. In at least some such embodiments encompassed herein, the electromagnets are positioned on or as part of the stator in place of permanent magnets that conventionally might be employed on the stator. The electromagnets can be powered or unpowered as needed or depending upon the circumstance. Given this to be the case, the magnetic cycloid gear assembly or system operates as an electromagnetically-controlled (or powered) magnetic gearbox that both can operate as a conventional magnetic gearbox when powered, and also can “disengage” to allow freewheeling of the output when necessary.

In at least some embodiments encompassed herein, the magnetic cycloid gear assemblies or systems (or gearboxes) encompassed herein are configured to achieve enhanced torque capacity (e.g., by comparison with some conventional embodiments of magnetic cycloid gear assemblies, systems, or gearboxes). In at least some such embodiments in which electromagnets are employed (e.g., on the stator), improved torque capacity is achieved by switching on and off the electromagnets (e.g., switching on and off the magnets electromagnetically, or switching on and off the currents flowing through the electromagnets) depending on whether the particular electromagnets are acting to contribute positively or negatively to torque. Further, in at least some additional embodiments, the polarity of certain ones of the electromagnets or electromagnetic poles can be reversed to potentially increase the torque capacity even further. In general, by appropriate switching or polarity reversals of various ones of the electromagnets, magnetic attraction between negatively contributing pole pairs in the large air gap can be reduced or prevented, which in turn allows for greater torque to be communicated by way of the overall magnetic cycloid gear assembly or system (or gearbox).

Magnetic cycloidal gear assemblies as disclosed or encompassed herein can be used in a wide variety of applications. For example, in some embodiments, such magnetic cycloidal gear assemblies can be incorporated into servo actuators. In at least one example, servo actuators including such magnetic cycloidal gear assemblies of the present technology can be used for aerospace applications such as flight surface control applications. Further, magnetic cycloid gear assemblies of the present technology can be made with various gear ratios, and can have various rotations per minute, depending upon the application or desired level of power output. Although the present disclosure particularly envisions the application or implementation of electromagnets with respect to magnetic cycloidal gear assemblies or systems (or gearboxes), the present disclosure also encompasses embodiments in which electromagnets are applied to other topologies (e.g., other gearbox or transmission topologies) as well.

One example of a magnetic cycloidal gear assembly100that includes electromagnets in accordance with the present technology is shown inFIGS.2,3,4,5, and6. The magnetic cycloidal gear assembly100is shown, in its entirety, inFIGS.5and6, which (among other aspects) illustrate schematically a controller250that serves to govern the providing of power to the electromagnets of the magnetic cycloidal gear assembly, along with associated power/control linkages252. By contrast,FIGS.2and4show portions190of the magnetic cycloidal gear assembly100that omit the controller250and associated power/control linkages252, andFIG.3particularly shows a cycloid104of that gear assembly.FIG.4particularly provides a cross-sectional view of the portions190of the magnetic cycloidal gear assembly100when those portions are fully assembled. The particular cross-sectional view provided inFIG.4is taken along a plane that passes through a schematic primary axis101of the magnetic cycloidal gear assembly100.

As shown inFIGS.2and4, the magnetic cycloidal gear assembly100includes a stator102, a cycloid104, an input shaft106, an output hub108, a bushing214, a plurality of cam followers110, and a counterweight112. The stator102is fixed and concentric with respect to the schematic primary axis101of the magnetic cycloidal gear assembly100, such that the schematic primary axis101intersects a center point103of the stator102when the magnetic cycloidal gear assembly100is assembled and mounted. The stator102is generally annular in shape and has an outer cylindrical surface105and an inner cylindrical surface107. In the present example, the stator102includes a back-iron cylinder118having an outer rim that constitute the outer cylindrical surface105, and additionally a plurality of teeth (e.g., m teeth)120that each protrude radially inwardly from the back-iron cylinder towards the center point103of the stator102.

The stator102also has a number of (e.g., m) electromagnets122, with each of the electromagnets being mounted between a respective pair of the teeth120and facing inwardly towards the center point103of the stator102. Innermost surfaces of the teeth120and of the electromagnets122together form the inner cylindrical surface107of the stator102. Each of the electromagnets122has a respective inner surface along the inner cylindrical surface107and can be powered so that the respective inner surface constitutes a respective positive pole114. When the electromagnets122are powered to provide the positive poles114(along the inner surfaces of those electromagnets), then each of the teeth120is a respective negative pole116. In this regard, the respective teeth120also can be considered respective consequent poles by comparison with the positive poles114provided by the respective electromagnets122.

With such arrangement, the stator102can be understood to include a first number of electromagnetically-generated pole pairs, such as m (or alternatively m+1) magnetic pole pairs, with each magnetic pole pair having a respective one of the positive poles114and a respective one of the negative poles116. Although in this arrangement, it is particularly the positive poles114that are provided by the electromagnets (or windings or coils)122, with the negative poles116being provided by way of the teeth120as consequent poles, this need not be the case in other embodiments. In particular, in some alternate embodiments, electromagnets (or windings or coils) are employed for both the positive and negative poles—that is, certain ones of the electromagnets (or windings or coils) serve as the positive poles while other ones of the electromagnets (or windings or coils) serve as the negative poles.

Referring additionally toFIG.3, the cycloid104serves as a rotor that is configured to rotate within the stator102during operation of the magnetic cycloidal gear assembly100. The cycloid104is mounted eccentrically with respect to the schematic primary axis101of the magnetic cycloidal gear assembly100, such that the schematic primary axis101does not intersect a center point (or center axis)109of the cycloid104when the magnetic cycloidal gear assembly100is assembled and mounted. The cycloid104can be mounted onto the input shaft106by a rolling element bearing162on an offset cam136(seeFIGS.2and4). The rolling element bearing162can be, in an example embodiment, a radial bearing. An outer cylindrical surface111of the cycloid104particularly is the surface that effectively rolls around the inner cylindrical surface107of the stator102(except insofar as an air gap separates the two surfaces) when the cycloid rotates during operation of the magnetic cycloidal gear assembly100.

Further as shown inFIG.3, the cycloid104has a second number of magnetic pole pairs, such as n (or alternatively m) magnetic pole pairs, with each magnetic pole pair having a respective negative pole124and a respective positive pole126. Because the cycloid104is configured to fit and rotate within the stator102during operation as the rotor of the magnetic cycloidal gear assembly100, the number of magnetic pole pairs n of the cycloid is less than the number of magnetic pole pairs m of the stator102. Depending upon the embodiment, the number of magnetic pole pairs n of the cycloid104can be less than the number of magnetic pole pairs m of the stator102by at least one magnetic pole pair, or by more than one magnetic pole pair.

In the present example embodiment, the cycloid104includes a back-iron cylinder (or disk)128having a plurality of (e.g., n) teeth130, and additionally includes a number of (e.g., n) permanent magnets132, with each of the permanent magnets being mounted between a respective pair of the teeth. The permanent magnets132of the cycloid104are arranged to each face outwardly away from the center point109, and also each of the teeth130extends radially outwardly from the back-iron cylinder128, so as to extend in between a respective pair of the permanent magnets132. Given this arrangement, it can be seen that the outer cylindrical surface111of the cycloid104is formed by the radially-outermost surfaces of the permanent magnets132and teeth130. The polarities of the teeth130and permanent magnets132are opposite those of the teeth120and electromagnets122of the stator102when the electromagnets are powered. That is, each of the permanent magnets132of the cycloid104is a respective one of the negative poles124, and each of the teeth130is a respective one of the positive poles126. The respective teeth130also can be considered respective consequent poles by comparison with the respective permanent magnets132.

Notwithstanding the above discussion, the stator102in other embodiments can have any other suitable arrangement that provides magnetic pole pairs. For example, a Halbach array or series of Halbach arrays can be used in place of the back-iron of the stator102. Also, the electromagnets122on the stator102can be arranged to serve as negative poles (in terms of the polarity of the electromagnets along the inner cylindrical surface107), and the teeth120in between those permanent magnets can serve as positive poles. Likewise, in other embodiments the cycloid104(or rotor) can have any other suitable arrangement that provides magnetic pole pairs. Again for example, a Halbach array or series of Halbach arrays can be used in place of the back-iron of the cycloid104. Additionally, the permanent magnets132on the cycloid can be arranged to serve as positive poles (in terms of the polarity of the permanent magnets along the outer cylindrical surface111), and the teeth130can serve as negative poles. Also, different permanent magnets can be employed both to serve as positive poles and also to serve as negative poles on the cycloid.

Further, although in the present embodiment it is the stator102that includes the electromagnets122and the cycloid104that includes the permanent magnets132, in alternate embodiments encompassed herein it is the cycloid that includes electromagnets and the stator that includes permanent magnets. Additionally, in some further alternate embodiments, each of the stator and the cycloid includes electromagnets. In some such embodiments, the electromagnets of the stator can have one polarity (e.g., a positive polarity, or alternatively a negative polarity) and the electromagnets of the cycloid can have the opposite polarity (e.g., a negative polarity, or alternatively a positive polarity). Also, in some alternate embodiments, one or both of the stator and the cycloid include a combination of one or more electromagnets and one or more permanent magnets.

Further, as discussed in additional detail below, in at least some embodiments encompassed herein, different ones of the electromagnets can be actuated differently and/or the actuation status of the respective electromagnets can be varied over time. For example, in some embodiments encompassed herein, certain electromagnets are actuated when other electromagnets are disabled, or certain electromagnets are actuated with a first (e.g., normal) polarity when other electromagnets are actuated with a second (e.g., reversed) polarity. In some such embodiments, the actuation statuses of the different electromagnets of the magnetic cycloidal gear assembly respectively are changed as time goes by during operation of the gear assembly, particularly as the cycloid104moves relative to (e.g., rolls within) the stator102in response to rotation of the input shaft106and/or in response to other forces/torques such as torques communicated to the cycloid104from a load (e.g., by way of output components such as the output hub108, the bushing214, and the plurality of cam followers110).

In the present embodiment, the cycloid104is caused to rotate as a result of rotation of the input shaft106. As shown inFIG.2, the input shaft106includes the offset cam136, which is positioned within and supports the cycloid104by way of the rolling element bearing162. In general, the input shaft106is concentric with respect to the schematic primary axis101of the magnetic cycloidal gear assembly100. However, the offset cam136is offset with respect to the schematic primary axis101of the magnetic cycloidal gear assembly100, with one side of the offset cam136extending outwardly from the input shaft106farther than the other side of the offset cam. In the present example embodiment, in which the offset cam136is circular, the offset cam136is concentric with the cycloid104.

As shown inFIG.4, the cycloid104can include a cycloid lip (or shoulder)168, and can be mounted on the rolling element bearing162in part by way of the cycloid lip168. As illustrated, the cycloid lip particularly extends radially inwardly along a side portion of the rolling element bearing162, along the side of the rolling element bearing that is closer to (rather than farther from) the output hub108. Further, the offset cam136includes an offset cam shoulder170that extends radially outward from the remainder of the offset cam alongside the rolling element bearing162, on the side of the rolling element bearing that is farther from (rather than closer to) the output hub108.

In addition to being caused to rotate as a result of rotation of the input shaft106, the cycloid104and magnetic cycloidal gear assembly100more generally are configured so that rotation of the cycloid additionally causes rotation of the output hub108. In this regard, the cycloid104includes a plurality of cam follower retainers134, each of which is configured to receive a respective one of the cam followers110. Each of the plurality of cam followers110has a first end138and a second end140. The second end140of each of the plurality of cam followers110is retained by a respective one of the cam follower retainers134, and is thus fixed to the cycloid104. Further, the output hub108presses against the bushing214, which can be an oil impregnated bushing, and the bushing can also press against the cycloid104. The bushing214can include a plurality of bores221(seeFIG.4), and each of the plurality of cam followers110can pass through a respective one of the bores221. The plurality of cam followers110can thus connect the bushing214to the cycloid104.

It should be appreciated that the exact arrangement of the bushing214, cam followers110, and cam follower retainers134can vary depending upon the embodiment. For example, any suitable number of the cam follower retainers134and any suitable number of the bores221can be included, preferably at least two of each, or more than two of each, such as three, four, five, or more than five. For example, in the present embodiment, six of the cam follower retainers134and six of the bores221are present in the cycloid104and the bushing214, respectively. Likewise, any suitable number of the cam followers110can be included in the magnetic cycloidal gear assembly100. Accordingly, at least two of the cam followers110can be provided, or more than two, such as three, four, five, or more than five. For example, in the present embodiment, six of the cam followers110are present. Preferably a respective one of the cam followers110is provided for each of cam follower retainers134of the cycloid104.

The cam followers110particularly allow for rotational motion of the cycloid104to be communicated to the output hub108, which is concentric with the schematic primary axis101of the magnetic cycloidal gear assembly100. The output hub108includes an output disk142, an output shaft144, and an intermediate portion164positioned between the output shaft and output disk and having a diameter that is larger than that of the output shaft. The output shaft144is concentric with the schematic primary axis101, can be connected to another device, and can be used to transmit the speed and torque output (or generated) by the magnetic cycloidal gear assembly100to another device (not shown). The output disk142includes a plurality of cam follower receivers146. Each of the cam follower receivers146has a receiver radius (or diameter) that is larger than a first end radius (or diameter) of each of the first ends138of each of the cam followers110. By virtue of this difference in size of the receiver radius and first end radius, the respective first end138of each of the cam followers110can rotate eccentrically within the respective one of the cam follower receivers146in which that first end is positioned, even though the output hub108and cam follower receivers146thereof do not vary in their radial positioning relative to the schematic primary axis101.

From the above discussion, it should be appreciated that the output hub108is interactively connected to the cycloid104by the cam followers110, and the cam followers110transmit output torque and rotation from the cycloid104to the output hub. That is, as the cycloid104rotates relative to the stator102, rotational power is transferred from the cycloid104to the output hub108by way of the plurality of cam followers110and their interactions with the cam follower receivers146. The use of the plurality of cam followers110can eliminate the need for rolling pin elements, and can significantly reduce the rolling resistance and therefore improve the efficiency of the magnetic cycloidal gear assembly100as compared to some conventional magnetic cycloidal gear assemblies. Additionally, oil (or other lubricant) can be delivered to the bores221, and thereby to the cam followers110, the cam follower receivers146, and the interface between output hub108and the bushing218to facilitate relative movement of these component parts (and especially any sliding movement of the bushing relative to the output hub).

In some embodiments, also encompassed herein, each of the cam followers110can include a respective roller bearing (or similar rolling head or wheel feature) at the respective first end138of the respective cam follower, as a respective head of the respective cam follower. With such an arrangement, movement of the cam followers110within the cam follower receivers146entails rotational motion of the roller bearings relative to the remaining portions of the cam followers (e.g., the second ends140), and sliding motion (and consequent friction) of the cam followers relative to the cam follower receivers is lessened or avoided. Also, in some embodiments encompassed herein, a set of rolling element bearings that are fixed to the cycloid104operate to transmit torque from the cycloid to the output hub108.

FIG.4additionally illustrates how the input shaft106and output hub108are supported relative to one another. In the present embodiment, an input shaft receiver165(which defines an input shaft receiving orifice) is provided within the output hub108and particularly extends inwardly from the end surface of the output disk142and into the intermediate portion164, toward (but not up to) the output shaft144. The input shaft receiver165is configured to receive a first end166of the input shaft106as well as an input shaft bearing212. More particularly, the input shaft bearing212can be inserted into the input shaft receiver165, and the first end166of the input shaft106can be inserted into the input shaft bearing. The input shaft bearing212can be a roller bearing, and can prevent radial movement of the input shaft106while allowing the input shaft106to rotate within the input shaft receiver165. Therefore, the input shaft106(at least the first end166of the input shaft) is rotatably supported upon and within the output hub108by way of the input shaft bearing212.

As for the counterweight112, as shown inFIGS.2and4, the counterweight is attached to the input shaft106. The counterweight112can have a clamp148, a first lobe150and a second lobe152. The clamp148can attach the counterweight112to the input shaft106such that the counterweight112can rotate with the input shaft106. The counterweight112can balance out the mass imbalance caused by the rotation of the eccentrically mounted cycloid104.

Referring additionally toFIGS.5and6, front elevation views are provided to illustrate the magnetic cycloidal gear assembly100at different times during operation, at which the cycloid104has two different positions relative to the stator102.FIG.5particularly provides a front elevation view of the magnetic cycloidal gear assembly100when the cycloid104is in a first position, which corresponds to what is shown inFIG.4(in terms of the rotational orientation of the cycloid104about the schematic primary axis101). By contrast,FIG.6provides a front elevation view of the magnetic cycloidal gear assembly100when the cycloid104is in a different, second position. Thus, the relative rotation of the rotor (cycloid104) and stator102of the magnetic cycloidal gear assembly100can be seen by comparingFIG.5withFIG.6. Additionally it should be appreciated thatFIGS.5and6also show corresponding different positions of other components or portions of the magnetic cycloidal gear assembly100that also vary in their positions when the cycloid varies in its rotational positioning.

As will be appreciated from the above discussion, movement of the cycloid104results from rotation of the input shaft106and offset cam136, which causes different ones of the positive poles114and negative poles116of the stator102to come into proximity with different ones of the negative poles124and positive poles126of the cycloid104. Due to the interactions between these pole pairs, slipping motion between the outer cylindrical surface111of the cycloid104and the inner cylindrical surface107of the stator102is prevented. Stated in another manner, the magnets in essence prevent “slippage” of the cycloid104(serving as the rotor) relative to the stator102and thus, due to the magnetic interaction between the pole pairs of the stator102and the pole pairs of the cycloid104, the cycloid rotation couples to the input shaft rotation as the magnets continue to seek their state of lowest potential (relatedly, it can be said that the magnetic forces provide the torque reaction allowing for the gearbox to transmit torque from input to output, as the cycloid would otherwise just spin on its bearing).

Consequently, as governed by the interaction of the magnetic pole pairs on the cycloid104and stator102, rotation of the input shaft106and offset cam136causes the outer cylindrical surface of the cycloid104to “roll along” the inner circular surface107of the stator102(with those surfaces only being separated by an air gap), in an eccentric manner. The first position ofFIG.5(andFIG.4) shows the magnetic cycloidal gear assembly100at the start of a 360° revolution of the input shaft106(and offset cam136), when the position of the cycloid104is closest to the uppermost portion of the inner cylindrical surface107of the stator102. By comparison, the second position ofFIG.6is half way through the revolution of the input shaft106, at 180° from the first position, when the position of the cycloid104is closest to the lowermost portion of the inner cylindrical surface107of the stator102.

The particular gear ratio achieved between the input rotation experienced by the input shaft106and the output rotation experienced by the output hub108depends upon the relative numbers of magnetic pole pairs on the stator102and on the cycloid104. If one assumes, as shown inFIGS.5and6, that the cycloid104has one fewer magnetic pole pair than the stator102, then for every full rotation of the input shaft106, the cycloid104must rotate one full rotation plus and additional amount to make up the difference. Supposing for example that the stator102has m+1 pole pairs and the cycloid104has m pole pairs, for a point on the cycloid after one full rotation of the input shaft106, the point will have moved to a position equivalent to −1/m rotations, where the negative sign indicates that the rotation is in the opposite sense to the rotation of the input shaft.

Because the cycloid104is supported upon the offset cam136and rotates eccentrically within the stator102, and given the magnetic interactions between the cycloid104and stator102, the amount of air gap (or space) between the stator102and the cycloid104varies at any given point around the inner cylindrical surface107of the stator102as the cycloid104rotates. Nevertheless, there is always a minimum gap220between the stator102and the cycloid104at a first point and a maximum gap222at a second point, and the locations of those points rotate as the cycloid104rotates in response to rotation of the input shaft106and offset cam136. The minimum gap220particularly always is in line with the high point of the offset cam136.

For example, as can be seen with reference toFIG.5(andFIG.4), when the cycloid104is in the first position, the minimum gap220between the stator102and the cycloid104is at the top (as illustrated inFIGS.5and4) of the stator102and the cycloid104, and then the maximum gap222is at the bottom of the stator102and the cycloid104. In contrast, as can be seen with reference toFIG.6, when the cycloid104in the second position, the minimum gap220between the stator102and the cycloid104is at the bottom (as illustrated inFIG.6) of the stator102and the cycloid104, while the maximum gap222is schematically at the top of the stator102and the cycloid104.

FIGS.5and6additionally show how other components or portions of the magnetic cycloidal gear assembly100rotate or otherwise move in conjunction with rotation of the input shaft106and offset cam136and consequent movement of the cycloid104. In particular,FIG.5shows that, when the cycloid104is in the first position, each of the first ends138of the respective cam followers110is at the respective top of the respective cam follower receiver146into which the respective first end is positioned. In contrast,FIG.6shows that, when the cycloid104is in the second position, each of the first ends138of the respective cam followers110is at the respective bottom of the respective cam follower receiver146into which the respective first end is positioned. Thus, the eccentric rotation of the cam followers110within the cam follower receivers146that accompanies the eccentric rotation of the cycloid104can be appreciated fromFIGS.5and6.

As noted above,FIGS.5and6show the entire magnetic cycloidal gear assembly100of the present embodiment and, more particularly, each ofFIGS.5and6(in contrast toFIGS.2and4) also shows schematically the controller250for governing actuation of the electromagnets122of the stator102of the magnetic cycloidal gear assembly100, along with the associated power/control linkages252. It should be appreciated that the controller250can take any of a variety of forms depending upon the particular embodiment or implementation. For example, the controller250can take the form of a microprocessor or computer, including a computerized device that operates in accordance with software. Also for example, the controller250can take the form a hardwired control device or a programmable logic device, or multiple such devices, or a drive.

Preferably, the controller250is able to output electric power (and particularly current) to the electromagnets122by way of the power/control linkages252that is sufficient to enable the electromagnets to generate sufficient magnetic fields to allow the magnetic cycloidal gear assembly100to transmit rotational power. Depending upon the embodiment, the controller250can operate independently or, alternatively, the controller250can operate at least partly based upon or in response to commands, control signals, or information received by way of wired or wireless communications from another device, source, or location, including for example a remote controller or from the cloud (not shown). Also, in at least some embodiments, the controller250operates directly or indirectly based upon or in response to operator input commands or signals, and/or based upon or in response to sensed information, including for example information regarding the speed or torque of the input shaft106or regarding the speed or torque of the output shaft144(or structure(s) coupled thereto).

With respect to the power/control linkages252, the manner in which these are illustrated inFIGS.5and6is merely intended to be illustrative of the existence of connections between the controller250and the electromagnets122by which electric power (and particularly current) can be provided to the electromagnets so that magnetic fields are generated by the electromagnets. The exact number and type of structures that are employed as the power/control linkages252can vary depending upon the embodiment. In the present example, the power/control linkages252include a first linkage254and a second linkage256. Each of the first and second linkages254and256extends from the controller250to the stator102and then, within (or alongside) the stator, is coupled to each of the electromagnets252. (For simplicity of illustration, the portions of the first and second linkages254and256that are within the interior of or alongside the stator102are illustrated by dashed lines, with only some portions of the linkages connected to some of the electromagnets122being shown, and other portions being cutaway and not shown.)

It is intended that the present disclosure encompass any of a variety of embodiments or arrangements of power/control linkages252in addition to the power/control linkages illustrated inFIGS.5and6. For example, although the manner in which the first and second linkages254and256are shown inFIGS.5and6can be understood as indicating that all of the electromagnets252are electrically coupled in parallel with one another between the first linkage254and the second linkage256, it should be appreciated that all of the electromagnets can alternatively be coupled in series between the first linkage254and the second linkage256.

Further, the manner in which the power/control linkages252are illustrated inFIGS.5and6is intended to be representative of a variety of different types of connections and configurations by which operations/actuations of the electromagnets122can be controlled, influenced, or governed by the controller, including connections or configurations by which different respective ones of the electromagnets can be individually actuated or deactivated (or disabled) in different respective manners. For example, each of the first linkage254and the second linkage256can be understood to represent a respective bus that includes a respective plurality of connections (e.g., wires or other links), where the respective connections of each respective bus are respectively connected between the controller250each of the respective electromagnets122(or to respective individualized switches associated with the respective electromagnets) so as to allow for individualized control/actuation of the respective electromagnets.

Given this embodiment, when electric power (particularly current) is directed from the controller250to the electromagnets122via the first linkage254(or alternatively the second linkage256), that electric current is directed to and passes through the electromagnets and then returns via the second linkage256(or alternatively the first linkage254). During such operation, all of the electromagnets122turn “on” in response to the current conducted therethrough, and all of the electromagnets are simultaneously activated in terms of producing magnetic fields. Correspondingly, when the controller250ceases to direct electric power (particularly current) through the first linkage254(or alternatively the second linkage256), then all of the electromagnets122are turned “off” and simultaneously deactivated such that no magnetic fields are generated by the stator102.

In the present embodiment, the controller250particularly is configured to cause electric power (and current) to pass through the electromagnets122during a normal mode of operation, but to cease directing electric power (and current) flow through the electromagnets during a clutch mode of operation, when clutch functionality is desired. During normal operation when it is desired that the magnetic cycloidal gear assembly100generate output rotation at the output hub108in response to input rotation of the input shaft106in accordance with the gear ratio established by the pole pairs of the stator102and cycloid104, the controller250actuates the electromagnets122to prevent slippage between the cycloid and the stator as discussed above.

However, when the electromagnets122are disabled during the clutch mode of operation (or possibly under other special circumstances when normal operation is not desired), the electromagnets of the stator102and permanent magnets132of the cycloid104will no longer prevent slipping between the cycloid and stator, and the magnetic cycloidal gear assembly (or gearbox)100will be able to freewheel. Stated in another manner, the electromagnets122and permanent magnets132in this circumstance no longer provide a torque reaction, and any torque applied at the input or output will simply cause the rolling element bearing162to spin. In such circumstance, the freewheel torque (e.g., as provided at the output shaft108) will be a function only of the drag caused by the rolling elements, the inertia of the cycloid104, and any secondary electromagnetic effects caused between the magnets and the unenergized electromagnets122(or windings or coils).

It should be recognized that magnetic cycloid gear assemblies of the present technology can be supported or implemented within any of a variety of types of structures depending upon the embodiment, and can be employed in any of a variety of applications. Referring toFIG.7, in one example embodiment, the magnetic cycloidal gear assembly100can be contained within a housing300. As shown, the housing300includes an outer shell302that encloses the magnetic cycloidal gear assembly100. The housing300can also include a front cover304, which can be a removable access panel that, when removed, provides access to the inside of the housing300and the magnetic cycloidal gear assembly100. Additionally, the housing300can include one or more additional support and/or mounting structures to support, mount, or otherwise engage with the magnetic cycloidal gear assembly100.

For example, as shown inFIG.7, the housing300can include a connector306, which engages and connects at a first end to the output shaft144of the output hub108and at a second end to another device to transfer rotational power from the magnetic cycloidal gear assembly100to the other device, which can be external to the housing. If the input shaft106is also driven by a rotational power source external to the housing, a further connector (not shown) can also be provided to couple the input shaft with that rotational power source. Also for example, internally within the housing300, support and/or mounting structures (not shown) can be provided to support or mount the magnetic cycloidal gear assembly100within the housing300.

It should be appreciated that, in at least some embodiments, the controller250and power/control linkages252can be positioned within the housing300but that, in other embodiments, the controller250and/or portions of the power/control linkages252can be located outside of the housing even though other portions (e.g., the portions190discussed above) are positioned within the housing300. Also, it should further be appreciated that, although for purposes of the above discussion the magnetic cycloidal gear assembly100is considered to be distinct from (and situated within) the housing300, and is considered to not include the housing or any of the support or mounting structures or components associated therewith, nevertheless the magnetic cycloidal gear assembly can also be understood to include the housing and/or any such support or mounting structures or components.

In view of the above discussion it should be appreciated that the magnetic cycloidal gear assembly100described in regard toFIGS.2,3,4,5, and6can be operated in several modes of operation by virtue of the controller250causing the electromagnets122to be powered or unpowered. Referring toFIG.8, a flow chart800is provided to illustrate example steps of one example method of operation of the magnetic cycloidal gear assembly100in this regard. Notwithstanding what is shown inFIG.8, however, it should be understood that the present disclosure is intended to encompass numerous other methods of operation and associated steps of operation for magnetic cycloidal gear assemblies such as the magnetic cycloidal gear assembly100or other assemblies or systems, and is not limited to the method shown inFIG.8.

More particularly with respect to the method of operation illustrated by the flow chart800, the method begins at a first step802, at which a stator having magnetic devices including electromagnets is provided, such as the stator102with the electromagnets122. The first step802can also be considered an initial step at which the entire structure of the magnetic cycloidal gear assembly100is provided or set up for operation. Next, at a second step804, the controller250causes electric power (particularly current) to flow through the electromagnets122so as to generate magnetic fields. Further, at a third step806, rotational power transmission operation of the magnetic cycloidal gear assembly100begins insofar as input rotational power is received at the input shaft106including the offset cam136, such that the input shaft and offset cam rotate.

Then, at a fourth step808, the cycloid104is caused to eccentrically rotate within the stator102in response to the rotation of the offset cam136, consistent with magnetic interactions between the permanent magnets132of the cycloid and the electromagnets122of the stator102. Further, at a fifth step810, at least one portion of the received input rotational power is communicated from the cycloid104to the output hub108. In at least the present embodiment, the communication of this rotational power occurs due to interactions of the cam followers110with the cam follower receivers146of the output hub108. Additionally, at a sixth step812, the at least one portion of the input rotational power is output via the output hub (e.g., for receipt by a load or receiving device).

All of the steps804,806,808,810, and812can be considered to occur at a first time (or during a first time period) during which the magnetic cycloidal gear assembly100is operating in a normal mode of operation of the magnetic cycloidal gear assembly100. During such normal operation, the magnetic cycloidal gear assembly100operates to transmit rotational power between the input shaft106and the output hub108, with the rotational power being modified in terms of the rotational speed and torque in a manner consistent with the gear ratio of the magnetic cycloid gear assembly. However, as described above, in a clutch mode or other mode of operation of the magnetic cycloidal gear assembly, it can be desired that the output hub108be decoupled from the input shaft106so that the output hub experiences freewheeling.

In this regard, the method ofFIG.8additionally includes a seventh step814, at which the controller250ceases causing the electric power (and electric current) to be provided to the electromagnets122of the stator102, such that the electric power (and current) ceases to flow through those electromagnets. Upon this occurring, then at an eighth step816, the output hub108becomes rotationally decoupled from the input shaft106and freewheeling of the output hub is permitted. Although not shown inFIG.8, it should be appreciated that the steps of the flow chart800can be repeated such that the magnetic cycloidal gear assembly100repeatedly switches between operation in the normal mode and operating in a mode where freewheeling is possible. For example, upon completion of the eighth step816, the method can return to the step804at which electric power (and current) is again caused to flow through the electromagnets during a return to the normal mode of operation.

Turning now toFIGS.9,10,11, and12, the present disclosure additionally envisions embodiments and manners of operation in which different ones of the electromagnets122of the magnetic cycloidal gear assembly100are selectively actuated (or deactivated) in different respective manners so as to enable the magnetic cycloidal gear assembly100to deliver higher levels of torque to a load or to achieve higher torque capacity. Such selective actuation can involve, for example, switching on one or more of the electromagnets122while one or more others of the electromagnets are switched off, or causing one or more of the electromagnets122to be actuated with a first (e.g., normal) polarity while one or more others of the electromagnets are actuated with a second (e.g., reversed) polarity, or causing one or more of the electromagnets122to be differently actuated from one or more others of the electromagnets in some other manner (e.g., in terms of the relative magnitudes of the magnetic flux generated at the different electromagnets).

To illustrate such operation,FIGS.9,10,11, and12provide respective front elevation views900,1000,1100, and1200of portions of the magnetic cycloidal gear assembly100that show the same components as are present inFIGS.5and6, except for the output hub108, the bushing214, the plurality of cam followers110, the power/control linkages252, and the controller250, which are not shown. As described further below, the front elevation views900,1000,1100, and120also include several graphical features (e.g., arrows and Xs) that illustrate behavior or interactions involving the electromagnets122that allow for the delivery of higher levels of torque or for achieving higher torque capacity. The front elevation views900,1000,1100, and1200illustrate snapshots of the portions of the magnetic cycloidal gear assembly100during operation (e.g., at particular moments in time), when the cycloid104is at particular example positions relative to the stator102and the electromagnets122are actuated (or deactivated) in manners that are appropriate for the positions of the cycloid. Nevertheless, during operation of the magnetic cycloidal gear assembly100, the cycloid104can take on any of a variety of other positions other than the example positions shown inFIGS.9,10,11, and12and, when at such other positions, the electromagnets122can or will be actuated (or deactivated) in other manners that are appropriate for those other positions of the cycloid104.

AlthoughFIGS.9,10,11, and12are described below as showing the same magnetic cycloidal gear assembly100as was described above in regard toFIGS.2,3,4,5, and6,FIGS.9,10,11, and12are intended to illustrate manners of operation that differ from the manners of operation described above. Such different manners of operation can be achieved by way of different control operations or signals provided by the controller250and the power/control linkages252if the controller250and power/control linkages252are configured to enable individualized control/actuation of the respective electromagnets122. For example, operation in any of the manners described with reference toFIGS.9,10,11, and12particularly can be achieved if each of the first linkage254and second linkage256takes the form of (as already mentioned above) a respective bus that includes a respective plurality of connections by which the controller250can be coupled respectively to different respective ones of the electromagnets122. Given this to be the case, although the magnetic cycloidal gear assembly that is the subject ofFIGS.9,10,11, and12can be considered to be (or to be encompassed by) the magnetic cycloidal gear assembly100that has been described above in regard toFIGS.2,3,4,5, and6, one can also consider the magnetic cycloidal gear assembly that is the subject ofFIGS.9,10,11, and12to be a distinct magnetic cycloidal gear assembly or system that differs from the magnetic cycloidal gear assembly100.

FIGS.9and10particularly illustrate operation of the magnetic cycloidal gear assembly100in which certain ones of the electromagnets122of the magnetic cycloidal gear assembly100are selectively switched off at the same time when others of the electromagnets are switched on in order to deliver higher levels of torque or achieve higher torque capacity. To illustrate such operation, in addition to showing the stator102with the electromagnets122and the cycloid104with the permanent magnets132, the front elevation view900ofFIG.9additionally includes a plurality of outwardly-directed arrows902. The outwardly-directed arrows902are respectively representative of magnetic flux passing through and out of a first plurality904of the electromagnets122that are switched on (or actuated). In general, the arrows902are radially-outwardly directed away from the schematic primary axis101or the center point103(seeFIG.2).

Although each of the arrows902ofFIG.9is outwardly directed, the magnetic flux emanating from each of the respective electromagnets122of the first plurality904generally follows looping paths around each of those respective electromagnets. That is, after exiting each of the electromagnets122of the first plurality904(e.g., at the location of the respective arrowhead of the respective arrow902associated with the respective electromagnet), the magnetic flux then loops back radially-inwardly through the respective teeth120on the respective sides of the respective electromagnet, between the respective electromagnet and respective neighboring ones of the electromagnets, and then further loops back in an outwardly-directed manner so as to re-enter the respective electromagnet. Although not shown inFIG.9, it should be appreciated that the magnetic flux emanating from the permanent magnets132of the cycloid104can take the same, or substantially the same, paths as described in regard toFIG.1C.

In contrast to conventional arrangements such as that ofFIGS.1B and1C, which employ permanent magnets on both the stator52and the rotor54to continually generate magnetic flux without interruption,FIG.9additionally illustrates operation of the magnetic cycloidal gear assembly100in which not all of the electromagnets122are switched on (or actuated). Rather, even though each of the electromagnets122of the first plurality904of the electromagnets is shown to be switched on as indicated by the arrows902,FIG.9further indicates that each of the electromagnets of a second plurality906of the electromagnets is switched off, as represented by Xs908. More particularly in this regard, the first plurality904of the electromagnets122that are switched on are those of the electromagnets that are arranged within a first arc zone910extending around the stator102that extends approximately240degrees, on either side of a first location912of minimum airgap (e.g., near the top of the stator102as shown inFIG.9). In contrast, the second plurality906of the electromagnets122that are switched off particularly are those of the electromagnets that are arranged within a second arc zone914extending around the stator102that extends approximately120degrees, on either side of a second location916of maximum airgap (e.g., near the bottom of the stator102as shown inFIG.9), effectively between the limits of the first arc zone910.

It should be appreciated that, due to the switching on of the first plurality904of the electromagnets122in combination with (at the same time as) the switching off of the second plurality906of the electromagnets, operation of the magnetic cycloidal gear assembly100differs from the operation described above in regard to the conventional magnetic cycloidal gear assembly50ofFIGS.1B and1C. In particular, by switching on the electromagnets122of the first plurality904but switching off the electromagnets of the second plurality906, those of the poles of the stator102and cycloid104that are at or proximate to the first location912of the minimum airgap are able to effectively attract one another, but those of the poles of the stator and cycloid that are at or proximate to the second location916of the maximum airgap do not repel one another as would be the case in a conventional arrangement involving permanent magnets on both of the stator and rotor.

FIG.9illustrates an example positioning of the cycloid104relative to the stator102in an operational circumstance when no load is being borne by the magnetic cycloidal gear assembly100(or the cycloid104). By comparison,FIG.10illustrates an example positioning of the cycloid104relative to the stator102in an alternate operational circumstance that is identical to the operational circumstance associated withFIG.9except insofar as, in the alternate operational circumstance ofFIG.10, a load is borne by the magnetic cycloidal gear assembly100via the output components thereof (e.g., by way of the output hub108, the bushing214, the plurality of cam followers110). In the alternate operational circumstance ofFIG.10, each of the electromagnets122of the first plurality904of the electromagnets is switched on, and each of the electromagnets of the second plurality906is switched off, as was the case in the operational circumstance shown inFIG.9. Also, in the alternate operational circumstance ofFIG.10, the first location912of the minimum airgap and second location916of the maximum airgap continue to be at the same or substantially the same respective positions (e.g., at the top and bottom of the stator102, respectively) as shown inFIG.9.

However,FIG.10shows that, due to the loading of the magnetic cycloidal gear assembly100, the cycloid104has a rotational position relative to the stator102that is somewhat different than the rotational position of the cycloid relative to the stator shown inFIG.9. As illustrated, the cycloid104has a rotational position that is rotated slightly in a clockwise manner, in a direction indicated by an arrow1002, relative to the stator102, by comparison with the rotational position of the cycloid relative to the stator shown inFIG.9. Further,FIG.10figuratively illustrates by way of arrows1004the primary magnetic forces between the electromagnets122of the stator102and the permanent magnets132of the cycloid104. The primary magnetic forces represented by the arrows1004can be understood to be the strongest magnetic forces existing between different ones of the electromagnets122and the permanent magnets132, namely, the magnetic forces existing between those of the respective electromagnets122that are switched on and the respective ones of the permanent magnets132that are respectively positioned closest to those respective electromagnets.

As already described, in the operational circumstance illustrated byFIG.10(as well asFIG.9), it is the electromagnets122of the first plurality904that are switched on and the electromagnets of the second plurality906that are switched off. Given these switching statuses, the primary magnetic forces exist between each of the electromagnets122of the first plurality904of the electromagnets on the stator102and the closest respective ones of the permanent magnets132on the cycloid104. Accordingly,FIG.10shows respective ones of the arrows1004as extending to the respective electromagnets122of the first plurality904from closest respective ones of the permanent magnets132on the rotor. However, because each of the electromagnets122of the second plurality906of the electromagnets is switched off, no such primary magnetic forces exist between those electromagnets and any of the permanent magnets132on the cycloid104. Accordingly,FIG.10does not show any of the arrows1004as extending to any of the electromagnets122of the second plurality906. (Nor doesFIG.10show any arrows or other features that might represent secondary magnetic forces potentially existing between the electromagnets122of the first plurality904and others of the permanent magnets132on the cycloid104other than the respective permanent magnets that are closest to those electromagnets, because overall those secondary magnetic forces are much smaller in magnitude than the primary magnetic forces.)

Given this manner of generating forces between the electromagnets122and the permanent magnets132, the magnetic cycloidal gear assembly100is capable of achieving enhanced torque capacity by comparison with a conventional magnetic cycloidal gear assembly such as the magnetic cycloidal gear assembly50described above in regard toFIG.1D. It should be appreciated fromFIG.10that each of the arrows1004particularly includes a respective directional (e.g., vector) component that is opposed to the circumferential direction of the arrow1002. That is, each of the arrows1004ofFIG.10has a respective directional component that is tangent to a circle extending around the schematic primary axis101or the center point103(seeFIG.2), and/or is tangent to the inner cylindrical surface107of the stator102, and that further is opposed to the direction of the arrow1002. Thus, all of the primary forces between the electromagnets122and permanent magnets132corresponding to the arrows1004shown inFIG.10contribute positively to a torque that can be delivered by the magnetic cycloidal gear assembly100to a load (e.g., by way of the output components such as the output hub108, the bushing214, and the plurality of cam followers110). This is in contrast to the manner of operation of the conventional magnetic cycloidal gear assembly50ofFIG.1D, in which some of the forces associated with some of the arrows92include components that diminish the torque that can be delivered (e.g., the forces represented by the arrows92associated with the first ones94of the second permanent magnets76).

FIGS.9and10thus illustrate how the magnetic cycloidal gear assembly100can be operated so as to achieve enhanced torque capacity by switching off (or deactivating or disabling) certain ones of the electromagnets122around the stator102while switching on (or actuating) other ones of the electromagnets. More particularly, to achieve enhanced torque capacity, the controller250(via the power/control linkages252) causes those of the electromagnets122that are at or proximate to the location of the maximum airgap to be switched off, while also causing the other electromagnets that are at or closer (or proximate) to the location of the minimum airgap to be switched on. As illustrated inFIG.9by the arrows902and the Xs908, such operation maintains attractive forces at the first location of the minimum airgap912and avoids/alleviates repulsive forces at the second location of the maximum airgap916. Further as illustrated inFIG.10by the arrows1004, when the magnetic cycloidal gear assembly100is under load, the selective switching on of some of the electromagnets and turning off of others of the electromagnets (particularly those at or proximate to the maximum airgap) allows for the removal of any primary magnetic forces that do not contribute to the overall torque capacity (or net torque production), such that all primary magnetic forces contribute to rather than diminish that torque capacity.

FIGS.11and12additionally illustrate operation of the magnetic cycloidal gear assembly100in which certain ones of the electromagnets122of the magnetic cycloidal gear assembly100are switched on (or actuated) but selectively reversed in polarity, at the same time when others of the electromagnets are switched on with normal polarity, in order to deliver higher levels of torque or achieve higher torque capacity. To illustrate such operation, in addition to showing the stator102with the electromagnets122and the cycloid104with the permanent magnets132, the front elevation view1100ofFIG.11also includes both a plurality of outwardly-directed arrows1102and a plurality of inwardly-directed arrows1104. The outwardly-directed arrows1102are respectively representative of magnetic flux passing through and out of the first plurality904of the electromagnets122that are switched on (or actuated) with normal polarity. The inwardly-directed arrows1104are respectively representative of magnetic flux passing through and out of the second plurality906of the electromagnets that are switched on with reversed polarity.

In general, the arrows1102are radially-outwardly directed away from, and the arrows1104are radially-inwardly directed toward, the schematic primary axis101or the center point103(seeFIG.2). Although each of the arrows1102is outwardly-directed, and each of the arrows1104is inwardly-directed, the magnetic flux emanating from each of the respective electromagnets122generally follows looping paths around the respective electromagnet. That is, after exiting each of the electromagnets122of the first plurality904(e.g., at the location of the respective arrowhead of the respective arrow1102associated with the respective electromagnet), the magnetic flux then loops back radially-inwardly through the respective teeth120on the respective sides of the respective electromagnet, between the respective electromagnet and respective neighboring ones of the electromagnets, and then further loops back in an outwardly-directed manner so as to re-enter the respective electromagnet. Likewise, after exiting each of the electromagnets122of the second plurality906(e.g., at the location of the respective arrowhead of the respective arrow1104associated with the respective electromagnet), the magnetic flux then loops back radially-outwardly through the respective teeth120on the respective sides of the respective electromagnet, between the respective electromagnet and respective neighboring ones of the electromagnets, and then further loops back in an inwardly-directed manner so as to re-enter the respective electromagnet. Although not shown inFIG.11, it should be appreciated that the magnetic flux emanating from the permanent magnets132of the cycloid104can take the same, or substantially the same, paths as described in regard toFIG.1C.

In the present example embodiment ofFIG.11, the first plurality904of the electromagnets122that in the present embodiment are switched on with a normal polarity are again arranged within the first arc zone910. Also, the second plurality906of the electromagnets that in the present embodiment are switched on with the reversed polarity are arranged with the second arc zone914. Thus, the difference in the manner of operation of the magnetic cycloidal gear assembly100illustrated byFIG.11, relative to the manner of operation illustrated byFIG.9, is that inFIG.11the second plurality906of the electromagnets are still actuated with the reversed polarity, rather than being switched off as inFIG.9. Due to the actuation or switching on of the first plurality904of the electromagnets122with the normal polarity, in combination with (at the same time as) the actuation or switching on of the second plurality906of the electromagnets with the reversed polarity, operation of the magnetic cycloidal gear assembly100again differs from the operation described above in regard to the conventional magnetic cycloidal gear assembly50ofFIGS.1B and1C. In particular, by switching on the electromagnets122of the first plurality904with the normal polarity and switching on the electromagnets of the second plurality906with the reversed polarity, those of the poles of the stator102and cycloid104that are at or proximate to the first location912of the minimum airgap are able to effectively attract one another. Also, in this circumstance, those of the poles of the stator102and cycloid104that are at or proximate to the second location916tend to attract one another rather than repel one another (as would be the case in a conventional arrangement such as that ofFIGS.1B and1C).

It should be recognized thatFIG.11(as withFIG.9) illustrates an example positioning of the cycloid104relative to the stator102in an operational circumstance when no load is being borne by the magnetic cycloidal gear assembly100(or the cycloid104). By comparison,FIG.12illustrates an example positioning of the cycloid104relative to the stator102in an alternate operational circumstance that is identical to the operational circumstance associated withFIG.11except insofar as, in the alternate operational circumstance ofFIG.12, a load is borne by the magnetic cycloidal gear assembly100via the output components thereof (e.g., by way of the output hub108, the bushing214, the plurality of cam followers110). In the alternate operational circumstance ofFIG.12, each of the electromagnets122of the first plurality904of the electromagnets again is switched on with the normal polarity, and each of the electromagnets of the second plurality906again is switched on with the reversed polarity, as described in regard toFIG.11. Also, in the operational circumstance ofFIG.12, the first location912of the minimum airgap and second location916of the maximum airgap continue to be at the same or substantially the same respective positions (e.g., at the top and bottom of the stator102, respectively) as shown inFIG.11.

However, in the alternate operational circumstance ofFIG.12, the cycloid104has a somewhat different rotational position relative to the stator102than what is shown inFIG.11. More particularly in this regard,FIG.12shows that, due to the loading of the magnetic cycloidal gear assembly10, the cycloid104has a rotational position relative to the stator102that is rotated slightly in a clockwise manner relative to the stator102in a direction indicated by an arrow1202, by comparison with the rotational position of the cycloid relative to the stator shown inFIG.11.

Further,FIG.12figuratively illustrates by way of first arrows1204and second arrows1206the primary magnetic forces between the electromagnets122of the stator102and the permanent magnets132of the cycloid104. The primary magnetic forces represented by the first arrows1204can be understood to be the strongest magnetic forces existing between the electromagnets122of the first plurality904and the permanent magnets132, namely, the magnetic forces existing between those of the respective electromagnets122that are switched on with the normal polarity and the respective ones of the permanent magnets132that are respectively positioned closest to those respective electromagnets. By contrast, the primary magnetic forces represented by the second arrows1206can be understood to be the strongest magnetic forces existing between the electromagnets122of the second plurality906and the permanent magnets132, namely, the magnetic forces existing between those of the respective electromagnets122that are switched on with the reversed polarity and the respective ones of the permanent magnets132that are respectively positioned closest to those respective electromagnets. (However,FIG.12does not show any arrows or other features that might represent secondary magnetic forces potentially existing between the electromagnets122on the stator102and the permanent magnets132on the cycloid104other than the respective permanent magnets that are closest to those electromagnets, because overall those secondary magnetic forces are much smaller in magnitude than the primary magnetic forces.)

Given that the electromagnets122of the second plurality906are switched on with the reversed polarity, it should be appreciated that the second arrows1206are illustrated inFIG.12in a different manner than the first arrows1204. That is, although the first arrows1204are illustrated as extending to the electromagnets122of the first plurality904from the closest respective ones of the permanent magnets132, the second arrows1206are illustrated as extending to respective ones of the teeth120in between the electromagnets122of the second plurality906from the closest respective ones of the permanent magnets132. This manner of illustrating the primary magnetic forces experienced between the electromagnets122of the second plurality906and the permanent magnets132is appropriate because the permanent magnets132proximate those electromagnets are attracted to the teeth120rather than to the electromagnets122, and also insofar as the teeth120in between the electromagnets122can be effectively considered to form parts of those electromagnets122(as consequent poles thereof). Notwithstanding the manner in which the second arrows1206are illustrated inFIG.12, it should be appreciated that there also are magnetic forces that tend to attract the electromagnets122of the second plurality906to closest respective ones of the teeth130on the cycloid104in between the closest respective ones of the permanent magnets132.

Given this manner of generating forces between the electromagnets122and the permanent magnets132, the magnetic cycloidal gear assembly100is capable of achieving enhanced torque capacity by comparison with a conventional magnetic cycloidal gear assembly such as the magnetic cycloidal gear assembly50described above in regard toFIG.1D. It should be appreciated fromFIG.12that each of the first arrows1204particularly includes a respective directional (e.g., vector) component that is opposed to the circumferential direction of the arrow1202. That is, each of the first arrows1204ofFIG.12has a respective directional component that is tangent to a circle extending around the schematic primary axis101or the center point103(seeFIG.2), and/or is tangent to the inner cylindrical surface107of the stator102, and that further is opposed to the direction of the arrow1202. Thus, all of the primary magnetic forces corresponding to the first arrows1204shown inFIG.12, between the electromagnets122of the first plurality904and the permanent magnets132closest thereto, contribute positively to a torque that can be delivered by the magnetic cycloidal gear assembly100to a load (e.g., by way of the output components such as the output hub108, the bushing214, and the plurality of cam followers110).

Additionally, it should further be appreciated fromFIG.12that each of the second arrows1206particularly includes a respective directional component that also is opposed to the circumferential direction of the arrow1202. That is, each of the second arrows1206ofFIG.12has a respective directional component that is tangent to a circle extending around the schematic primary axis101or the center point103(seeFIG.2), and/or is tangent to the inner cylindrical surface107of the stator102, and that further is opposed to the direction of the arrow1202. Thus, all of the primary magnetic forces corresponding to the second arrows1206shown inFIG.12, between the electromagnets122of the second plurality906and the permanent magnets132closest thereto, also contribute positively to the torque that can be delivered by the magnetic cycloidal gear assembly100to a load (e.g., by way of the output components such as the output hub108, the bushing214, and the plurality of cam followers110). Thus, due to the reversal in the polarity of the electromagnets122of the second plurality906, all of the primary magnetic forces between the permanent magnets132and the electromagnets122contribute to the overall torque that can be delivered to the load. This is in contrast to the manner of operation of the conventional magnetic cycloidal gear assembly50ofFIG.1D, in which some of the forces associated with some of the arrows92include components that diminish the torque that can be delivered (e.g., the forces represented by the arrows92associated with the first ones94of the second permanent magnets76).

FIGS.11and12thus illustrate how the magnetic cycloidal gear assembly100can be operated so as to achieve enhanced torque capacity by switching on certain ones of the electromagnets122around the stator102with a normal polarity while switching on other ones of the electromagnets with a reversed polarity. More particularly, to achieve enhanced torque capacity, the controller250(via the power/control linkages252) causes those of the electromagnets122that are at or proximate to the location of the maximum airgap to be actuated with a reversed polarity, while also causing the other electromagnets that are at or closer (or proximate) to the location of the minimum airgap to be actuated with a normal polarity. As illustrated inFIG.11by the outwardly-directed arrows1102and the inwardly-directed arrows1104, such operation maintains attractive forces at the first location912of the minimum airgap and maintains some level of attractive forces at the second location916of the maximum airgap. Further, as illustrated inFIG.12by the first and second arrows1204and1206, when the magnetic cycloidal gear assembly100is under load, the selective reversing of the polarity of certain ones of the electromagnets (e.g., those electromagnets at or proximate to the maximum/large air gap) allows for those certain ones of the electromagnets to contribute to the overall torque capacity (or net torque production) of the gear assembly, such that all primary magnetic forces contribute to rather than diminish that torque capacity.

As previously noted, the illustrations shown inFIGS.9,10,11, and12are merely intended to represent different snapshots of the magnetic cycloidal gear assembly100during operation. Notwithstanding what is shown inFIGS.9,10,11, and12, it should be understood that the movements of the magnetic cycloidal gear assembly100, and particularly the positioning of the cycloid104relative to the stator102(among other components of the gear assembly), will typically vary as the magnetic cycloidal gear assembly100operates. Thus, although the first location912of the minimum airgap and the second location916of the maximum airgap are respectively shown in each ofFIGS.9,10,11, and12to be proximate the top and bottom of the stator102, respectively, the rotational positions of those locations and airgaps will vary as the cycloid104moves within the stator102. Further, from the above discussion, it should be appreciated that the exact movements of the magnetic cycloidal gear assembly100, and particularly the positioning of the cycloid104relative to the stator102, can depend upon the manners or circumstances of operation, such as the manners or circumstances of operation described in regard toFIGS.9and10, or11and12(e.g., whether under load).

Given this to be the case, it should additionally be understood that, to achieve desired operation with enhanced torque capacity being provided by the magnetic cycloidal gear assembly100, the controller250(by way of the power/control linkages252) should operate to continually adjust the respective actuations of the respective electromagnets122as the cycloid104moves or rotates relative to the stator102. Indeed, notwithstanding the above description pertaining toFIGS.9,10,11, and12concerning how the first plurality904of the electromagnets122are switched on with normal polarity and concerning how the second plurality906of the electromagnets are either switched off (as inFIGS.9and10) or reversed in polarity (as inFIGS.11and12), during operation the respective subsets of the electromagnets122that are encompassed by the first plurality904and second plurality906will vary with movement/rotation of the cycloid104and/or based upon other considerations.

For example, if (contrary to what is shown inFIGS.9,10,11, and12) at another time the cycloid104rotates to a position such that the first location912of the minimum airgap is proximate the bottom of the stator102, then the first plurality904of the electromagnets122can potentially include all of the electromagnets arranged around the stator102within a 240-degree arc zone extending upwards by120degrees on either side of the bottom of the stator, and the second plurality906of the electromagnets can potentially include all of the remaining electromagnets of the stator102(e.g., within a 120-degree arc zone extending downward by 60 degrees on either side of the top of the stator). Correspondingly, at such a time, the controller250will cause those of the electromagnets122that are within the 240-degree arc zone to be switched on with the normal polarity. Also, at such a time, depending upon whether the magnetic cycloidal gear assembly100is being operated in accordance with the manner ofFIGS.9and10or the manner ofFIGS.11and12, the controller250will cause those of the electromagnets122that are within the120-degree arc zone either to be switched off or to be reversed in polarity.

Further in this regard,FIGS.13and14provide first and second flow charts1300and1400, respectively, to show example steps of first and second methods of operation, respectively, of the magnetic cycloidal gear assembly100. The first method of operation represented by the first flow chart1300particularly is a method of monitoring and controlling actuation of the electromagnets122by way of the controller250so as to achieve the manner of operation described in regard toFIGS.9and10. That is, the first flow chart1300illustrates the method of operation in which different subsets of the electromagnets122are switched off or deactivated at different times or circumstances, while other subsets of the electromagnets are switched on or actuated at those respective times or circumstances, to enhance torque capacity. By contrast, the second method of operation represented by the second flow chart1400is a method of monitoring and controlling actuation of the electromagnets122by way of the controller250so as to achieve the manner of operation described in regard toFIGS.11and12. That is, the second flow chart1400illustrates the method of operation in which different subsets of the electromagnets122are actuated with a first (e.g., normal) polarity at different times or circumstances, while other subsets of the electromagnets are actuated with a second (e.g., reversed) polarity at those respective times or circumstances, to enhance torque capacity.

More particularly with respect toFIG.13, the first method of operation represented by the first flow chart1300, upon starting at a start step1302, commences operation at a step1304at which a rotational position of the cycloid (or rotor)104is sensed. The sensing can be performed at a high speed shaft, or at the input shaft106, or alternatively at one or more other locations such as along the stator102(e.g., along the inner cylindrical surface107thereof), by way of any one or more of a variety of sensors or sensing devices or mechanisms. Upon being sensed, the sensed rotational position information is received by the controller250, also as part of the step1304.

Next, at a step1306, the controller250determines the sign of the torque produced by each one of the electromagnets (or electromagnetic coils)122on the stator102. In performing this operation, it will be appreciated that the controller250can, based upon the sensed information regarding the rotational position of the cycloid104obtained at the step1304, determine the position of each of the permanent magnets132of the cycloid104relative to the position of each of the electromagnets122of the stator102. Based upon these determinations of the relative positions, the controller250is further configured to determine whether the magnetic flux paths of the respective permanent magnets132are aligned with the magnetic flux paths of the respective electromagnets122that are positioned closest to those respective permanent magnets. Also, based upon these determinations of the relative positions, the controller250is additionally configured to determine whether the primary magnetic forces between the respective electromagnets122and the respective permanent magnets132positioned closest to those respective electromagnets tend to contribute positively to the torque output of the magnetic cycloidal gear assembly100or tend to diminish that torque output. If the primary magnetic force between a respective one of the electromagnets122and a corresponding (closest) respective one of the permanent magnets132contributes positively or adds to the torque output, the respective electromagnet can be determined to produce (or be assigned) a positive torque sign. Alternatively, if the primary magnetic force between a respective one of the electromagnets122and a corresponding (closest) respective one of the permanent magnets132contributes negatively to or diminishes the torque output, the respective electromagnet can be determined to produce (or be assigned) a negative torque sign.

Subsequently, at a step1308, the controller250generates or outputs control signals and communicates those control signals via the power/control linages252based upon the torque sign determinations to cause certain ones of the electromagnets122to be (or stay) switched on and to cause other ones of the electromagnets to be switched off. More particularly, the controller250will output and communicate control signals to each of the electromagnets122so that only those of the electromagnets (or electromagnetic coils) producing the desired sign of torque will be switched on or energized. For example, in the operational circumstance shown inFIGS.9and10, the controller250can determine that the electromagnets122of the first plurality904have a positive sign of torque and cause those electromagnets to be actuated, and further determine that the electromagnets of the second plurality906have a negative sign of torque and cause those electromagnets to be deactivated.

The controller250can govern the operations of the respective electromagnets122on an individualized basis. For example, as already mentioned, the power/control linkages252can include busses by which the controller250can be in direct communication with and exert control over the actuation/operation of each of the electromagnets122. In some embodiments or circumstances, the controller250can serve as a driver that controls the respective operations/actuations of the respective electromagnets122by supplying (or refraining from supplying) the respective actuating currents directly to the respective electromagnets. In other embodiments or circumstances, the controller250can output control signals to other devices that govern the respective operations/actuations of the respective electromagnets. For example, in some embodiments, the controller250can provide signals via the power/control linkages252to govern individual on/off circuitry (e.g., individualized switches controlled by the controller250) to control the actuation of each of the electromagnets122.

Upon completion of the step1308, as indicated by a step1310, the first method will often be repeated and return to the step1304. Indeed, during operation of the magnetic cycloidal gear assembly100, the steps of the first method can be repeated numerous times at a high frequency so that the controller250has sufficient information to modify the actuation status of the electromagnets122repeatedly and in a timely manner as the cycloid104moves relative to the stator102. During typical operation, the respective currents that are applied to the respective electromagnets122will change as the cycloid104moves within the stator102, based upon whether the respective electromagnet122is closer or farther from the minimum air gap (or farther or closer from the maximum air gap). In general, the controller250will cause each of the electromagnets122to be actuated (to conduct current) at certain respective times corresponding to certain positions of the cycloid104), and to be deactivated (to not conduct current) at other respective times corresponding to other positions of the cycloid.

Alternatively, as also represented by the step1310, at some point in time when operation of the magnetic cycloidal gear assembly100is no longer sought or needed, then the method can also end (that is, the step1310can also be considered an end step of the process).

Additionally with respect toFIG.14, the second method of operation represented by the first flow chart1400, upon starting at a start step1402, commences operation at a step1404at which a rotational position of the cycloid (or rotor)104is sensed. The sensing can be performed at a high speed shaft, or at the input shaft106, or alternatively at one or more other locations such as along the stator102(e.g., along the inner cylindrical surface107thereof), by way of any one or more of a variety of sensors or sensing devices or mechanisms. Upon being sensed, the sensed rotational position information is received by the controller250, also as part of the step1404.

Next, at a step1406, the controller250determines the sign of the torque produced by each one of the electromagnets (or electromagnetic coils)122on the stator102, so as to allow for a determination as to which of the electromagnets should be actuated with a normal polarity by application of a first current type (e.g., a positive current) or actuated with a reverse polarity by application of a second current type (e.g., negative current). In performing this operation, it will again be appreciated (as with respect to the step1306discussed above) that the controller250can, based upon the sensed information regarding the rotational position of the cycloid104obtained at the step1404, determine the position of each of the permanent magnets132of the cycloid104relative to the position of each of the electromagnets122of the stator102. Based upon these determinations of the relative positions, the controller250is further configured to determine whether the magnetic flux paths of the respective permanent magnets132are aligned with the magnetic flux paths of the respective electromagnets122that are positioned closest to those respective permanent magnets. Also, based upon these determinations of the relative positions, the controller250is additionally configured to determine whether the primary magnetic forces between the respective electromagnets122and the respective permanent magnets132positioned closest to those respective electromagnets tend to contribute positively to the torque output of the magnetic cycloidal gear assembly100or tend to diminish that torque output. If the primary magnetic force between a respective one of the electromagnets122and a corresponding (closest) respective one of the permanent magnets132contributes positively or adds to the torque output, the respective electromagnet can be determined to produce (or be assigned) a positive torque sign. Alternatively, if the primary magnetic force between a respective one of the electromagnets122and a corresponding (closest) respective one of the permanent magnets132contributes negatively to or diminishes the torque output, the respective electromagnet can be determined to produce (or be assigned) a negative torque sign.

Subsequently, at a step1408, the controller250generates or outputs control signals and communicates those control signals via the power/control linages252based upon the torque sign determinations to cause positive currents to be applied to one or more of the electromagnets122that were determined to produce positive torque signs. More particularly, the controller250will output and communicate control signals to those of the electromagnets (or electromagnetic coils)122producing the positive sign of torque so that those electromagnets will be switched on or energized with positive currents. Additionally, at a step1410, the controller250generates or outputs control signals and communicates those control signals via the power/control linkages252based upon the torque sign determinations to cause negative currents to be applied to one or more of the electromagnets122that were determined to produce negative (or undesired) torque signs. More particularly, the controller250will output and communicate control signals to those of the electromagnets (or electromagnetic coils)122producing the negative sign of torque so that those electromagnets will be switched on or energized with negative currents.

At the steps1408and1410, the controller250particularly can achieve polarity control of each of the electromagnets by controlling the directions of currents flowing through the respective electromagnets. For example, with respect to the operational circumstance shown inFIGS.11and12, the controller250can determine that the electromagnets of the first plurality904have a positive (or desired) sign of torque and cause positive (e.g., normal polarity) currents to be applied to those electromagnets, and additionally can determine that the electromagnets of the second plurality906have a negative (or undesired) sign of torque and cause negative (e.g., reversed polarity) currents to be applied to those electromagnets.

Further in regard to each of the step1408and step1410, the controller250can govern the operations of the respective electromagnets122on an individualized basis. For example, as already mentioned, the power/control linkages252can include busses by which the controller250can be in direct communication with and exert control over the actuation/operation of each of the electromagnets122. In some embodiments or circumstances, the controller250can serve as a driver that controls the respective operations/actuations of the respective electromagnets122by supplying the respective actuating currents directly to the respective electromagnets. In other embodiments or circumstances, the controller250can output control signals to other devices that govern the respective operations/actuations of the respective electromagnets. For example, in some embodiments, the controller250can provide signals via the power/control linkages252to govern individual on/off circuitry (e.g., individualized switches controlled by the controller250) to control the actuation of each of the electromagnets122.

Upon completion of the step1410, as indicated by a step1412, the second method will often be repeated and return to the step1404. Indeed, during operation of the magnetic cycloidal gear assembly100, the steps of the second method can be repeated numerous times at a high frequency so that the controller250has sufficient information to modify the actuation status of the electromagnets122repeatedly and in a timely manner as the cycloid104moves relative to the stator102. As already mentioned, during typical operation, the respective currents that are applied to the respective electromagnets122will change as the cycloid104moves within the stator102, based upon whether the respective electromagnet122is closer or farther from the minimum air gap (or farther or closer from the maximum air gap). In general, the controller250will cause each of the electromagnets122to conduct a normal-polarity current at certain respective times (corresponding to certain positions of the cycloid104) and to conduct a reversed-polarity current at other respective times (corresponding to other positions of the cycloid).

Alternatively, as also represented by the step1412, at some point in time when operation of the magnetic cycloidal gear assembly100is no longer sought or needed, then the method can also end (that is, the step1412can also be considered an end step of the process).

Notwithstanding the above description, the present disclosure is intended to encompass numerous alternate embodiments. For example, although the electromagnets can be located on the stator102as shown inFIGS.2,4,5,6,9,10,11, and12, electromagnets can alternatively be mounted on the cycloid104(or rotor), or be mounted on each of the stator and the cycloid. Also, althoughFIGS.2,4,5,6,9,10,11, and12concern the application of electromagnets and electromagnetic control to a particular example topology of a magnetic cycloidal gear assembly, the present disclosure is intended to encompass numerous other typologies including not only other typologies of cycloidal gears but also other topologies such as ones involving coaxial magnetic gears, magnetic spur gears, and other types of gears and gear arrangements.

Additionally, notwithstanding the above description, the controller250and power/control linkages252can take a variety of other forms depending upon the embodiment or circumstance, in addition to those described above. As already noted above, in some embodiments, the power/control linkages252can include one or more busses, where each bus includes a respective plurality of connections by which the controller250is coupled to the respective electromagnets. Additionally, in some alternate embodiments, the power/control linkages include a plurality of different linkages that are respectively coupled to different respective ones of the electromagnets122, even if those different linkages are not included within busses. Also, in some alternate embodiments, the controller can provide control signals to the electromagnets122(or to actuating devices for such electromagnets, such as individualized switches) at least in part by way of wireless communication links (which can, for example, form portions of the power/control linkages252).

Further as already noted above, in some embodiments, all of the electromagnets122need not be powered simultaneously. Rather, the controller250can actuate the different ones of the electromagnets122at respectively different times and/or in respectively different manners. In this regard, the present disclosure particularly has described above the simultaneous application of currents in one or more electromagnets while no currents are applied to one or more other electromagnets, as well as the simultaneous application of first-polarity (e.g., normal polarity) currents to one or more electromagnets while second-polarity (e.g., reversed polarity) currents are applied to one or more other electromagnets.

Nevertheless, the present disclosure also envisions other manners of actuating (or refraining from actuating) different ones of the electromagnets at the same time differently, and/or the application of other types of currents to various electromagnets of a magnetic cycloidal gear assembly. Indeed, for example, in some such embodiments, different respective actuating electrical currents can be applied by the controller250respectively to different ones of the electromagnets122so that different respective magnetic fields are generated by the different electromagnets (e.g., magnetic fields with different magnitudes or occurring at different times). Indeed, the present disclosure encompasses embodiments in which currents of different magnitudes are applied to different electromagnets of a magnetic cycloidal gear assembly. Also, for example, although it is envisioned above that the controller250will provide direct current (DC) power to the electromagnets122in the magnetic cycloidal gear assembly100ofFIGS.2-6and9-12described above, in other embodiments other forms of power (or current or voltage) can be provided to one or more of the electromagnets, such as alternating current (AC) power.

The present disclosure further envisions and encompasses alternate embodiments in which the operation of electromagnets as controlled by a controller (e.g., via power/control linkages) occurs in any of a variety of different or additional manners. In at least some such alternate embodiments, control of the electromagnets (or windings or coils) permits improved performance of the magnetic cycloidal gear assembly (or gearbox) by comparison with magnetic cycloidal gear assemblies (or gearboxes) that only employ permanent magnets but not electromagnets. Also, in at least some such alternate embodiments, the electromagnets (or windings or coils) can be controlled in any of a variety of modulated manners to achieve any of a variety of goals.

For example, in one such alternate embodiment, the controller can operate to modulate the electromagnets on the stator (e.g., the stator windings or coils) to “lead” the cycloid, so as to improve the output speed of the system at a given input torque over what a motor alone would be able to achieve. Also for example, in an additional such alternate embodiment, the controller can operate to modulate the electromagnets on the stator (e.g., the stator windings or coils) in a manner such that the gearbox operates at a different gear ratio than the inherent gear ratio, potentially optimizing for motor power or some other parameter. Further for example, in another such alternate embodiment, the controller can operate to modulate the electromagnets on the stator (e.g., the stator windings or coils) in a manner that reduces or minimizes the forces on the input shaft (e.g., magnetic and centripetal forces), so as to reduce the burden on the shaft and bearings, and potentially reduce the size and weight of the counterweight/counterbalance.

Additionally for example, in a further such alternate embodiment, the controller can operate to modulate the electromagnets on the stator (e.g., the stator windings or coils) in a manner that is independent of the motor to provide small or high frequency position adjustments. Also for example, in an additional such alternate embodiment, the controller can operate to modulate the electromagnets on the stator (e.g., the stator windings or coils) with respect to torque to improve the stiffness of the gearbox. Although each of these alternate embodiments involving various types of modulation particularly involves modulation of the electromagnets on the stator (or the power or currents delivered thereto), the present disclosure also is intended to encompass embodiments that involve modulation of electromagnets on a cycloid or rotor, instead of (or in addition to) modulation of electromagnets on a stator.

One or more of the embodiments encompassed herein can be advantageous in any of a variety of respects. For example, in at least some embodiments, the benefits of the technology include the ability to achieve very high gear ratios in a single stage, true zero-backlash operation, as well as reduced wear, reduced noise and improved reliability and life due to the lack of mechanically meshing gear teeth. Also for example, with respect to at least some embodiments encompassed herein, because the magnetic cycloidal gear assemblies (or gearboxes) employ electromagnets, the magnetic cycloidal gear assemblies can operate both as conventional magnetic gearboxes when powered (e.g., during a normal mode of operation), and also can “disengage” to allow freewheeling of the output when necessary (e.g., during a clutch mode of operation).

Further for example, with respect to at least some embodiments encompassed herein, any of a variety of different types of control over the actuation and deactivation (and/or modulation) of one or more of the electromagnets of a magnetic cycloidal gear assembly can be performed in order to achieve any of a variety of different types of operation. In particular, in at least some embodiments encompassed herein, a magnetic cycloidal gear assembly with enhanced torque capacity is achieved by causing different respective ones of the electromagnets to be actuated differently at any given time, and also actuated in a time-varying manner (such that the actuation status of any given one of the electromagnets changes over time) as the cycloid moves relative to the stator of the magnetic cycloidal gear assembly. As discussed above, depending upon the embodiment or operational circumstance, such differential manners of actuation can involve, for example, selectively actuating certain one(s) of the electromagnets while other one(s) of the electromagnets are deactivated or, also for example, selectively actuating certain one(s) of the electromagnets to have a first polarity while other one(s) of the electromagnets are actuated to have a second polarity. Additionally, the present disclosure is not limited to the embodiments employing magnetic cycloidal arrangements but rather encompasses embodiments having other structures and arrangements as well.