Rotational coupling device with bearing shield

Abstract

To provide a rotational coupling device having a shield which prevents fluid and particulate matter from reaching a bearing in the device, facilitates assembly of the device, and improves delivery of flux in the device.SOLUTION: The rotational coupling includes a hub assembly. The hub assembly includes a hub and a disk. An armature and an electromagnet are disposed on opposite axial sides of the disk. The electromagnet is fixed against rotation and a bearing is disposed between the hub and the electromagnet. The hub assembly and the electromagnet are separated by an air gap on an outboard side of the bearing. The debris shield is axially aligned with the air gap, extends over a radial length thereof, and is at least partially disposed within the air gap. The shield includes a fixed end coupled to one of the hub assembly and the electromagnet during assembly, and a free end configured to engage the other through a spring force and / or electromagnetic attraction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to rotary couplings, and in particular to rotary couplings having shields that prevent fluids and particulate matter from reaching bearings within the device while also facilitating assembly of the device and, in some embodiments, improving flux transfer within the device. [Background technology]

[0002] Rotary coupling devices, such as clutches and brakes, are used to control the transfer of torque between two bodies. In a conventional electromagnetic coupling device, a coupling disk or rotor is coupled to an input or output member and an armature located on one side of the disk and coupled to the other side of the input and output members. An electromagnet is located on the opposite side of the disk from the armature and is energized or deenergized to engage or disengage the armature from the disk, rotationally coupling or decoupling the input and output members and / or braking one of the members. The electromagnet is often fixed against rotation. Therefore, conventional coupling devices include bearings located between the electromagnet and the rotating parts of the coupling device. Depending on the application in which the device is used, the bearings may be exposed to contaminants such as fluids and / or dust, thereby shortening the life of the device.

[0003] To prevent contaminants from reaching the bearing, seals have been developed that can be attached to one of the bearing races and extend into the gap between the races. However, the use of these seals requires inventorying the seal and a separate operation to assemble the seal into the bearing. Furthermore, assembling the seal into the bearing race can be difficult and can result in damage to the bearing or alteration of its function.

[0004] To overcome the disadvantages associated with conventional seals, applicant has previously developed several debris shields, such as those described in U.S. Pat. No. 10,883,552 B2, the disclosure of which is incorporated herein by reference in its entirety. While these shields have functioned satisfactorily for their intended purposes, at least some of the shields still require the end user of the coupling device to assemble the shield to other components of the coupling device prior to use. As a result, assembling the shield can be inconvenient for the end user and can result in non-use of the shield. End users may also simply forget to install the shield or install the shield improperly, resulting in potential malfunction of the device. Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors herein have recognized a need for a rotary coupling device that minimizes and / or eliminates one or more of the above-identified disadvantages. [Means for solving the problem]

[0006] The present disclosure relates to rotary couplings, and in particular to rotary couplings having shields that prevent fluids and particulate matter from reaching bearings within the device while also facilitating assembly of the device and, in some embodiments, improving flux transfer within the device.

[0007] A rotary coupling device according to one embodiment of the present teachings includes a hub assembly configured to rotate about a rotational axis. The hub assembly includes a rotor hub disposed about the rotational axis and configured to receive a shaft, and a rotor disk extending radially outward from the rotor hub. The device further includes an armature disposed on a first axial side of the rotor disk and an electromagnet disposed on a second axial side of the rotor disk opposite the armature and fixed against rotation. The device further includes a bearing disposed between the rotor hub and the electromagnet. The hub assembly and the electromagnet are separated by an air gap on an outboard side of the bearing. The device further includes a shield disposed partially within the air gap and extending the entire radial length of the air gap. The shield has a fixed end that engages one of the hub assembly and the electromagnet and a free end opposite the fixed end that is configured to engage the other of the hub assembly and the electromagnet.

[0008] A rotary coupling device according to another embodiment of the present teachings includes a hub assembly configured to rotate about a rotational axis. The hub assembly includes a rotor hub disposed about the rotational axis and configured to receive a shaft, and a rotor disk extending radially outward from the rotor hub. The device further includes an armature disposed on a first axial side of the rotor disk and an electromagnet disposed on a second axial side of the rotor disk opposite the armature and fixed against rotation. The device further includes a bearing disposed between the rotor hub and the electromagnet. The hub assembly and the electromagnet are separated by an air gap on an outboard side of the bearing. The device further includes a shield extending the entire radial length of the air gap. The shield has a fixed end attached to the electromagnet and a free end opposite the fixed end configured to engage the hub assembly.

[0009] A rotary coupling device according to another embodiment of the present teachings includes a hub assembly configured to rotate about a rotational axis. The hub assembly includes a rotor hub disposed about the rotational axis and configured to receive a shaft, and a rotor disk extending radially outward from the rotor hub. The device further includes an armature disposed on a first axial side of the rotor disk, and an electromagnet disposed on a second axial side of the rotor disk opposite the armature and fixed against rotation. The device further includes a bearing disposed between the rotor hub and the electromagnet. The hub assembly and the electromagnet are separated by an air gap on an outboard side of the bearing. One of the hub assembly component and the electromagnet defines a radially extending shield, which is axially aligned with the air gap and extends across its entire radial length. The shield forms a unitary body with the hub assembly component and the one of the electromagnet.

[0010] A rotary coupling according to the present teachings offers advantages over conventional couplings. The coupling includes a shield that prevents contaminants, such as fluids and particulate matter, from reaching the device's bearings. The fixed end of the shield is coupled to the hub assembly or electromagnet and, therefore, may be included with the device as a pre-assembled unit, eliminating inconvenience to the device's end user and eliminating the possibility of the end user forgetting to install or improperly installing the shield. Furthermore, because the shield is not directly attached to the bearing race, potential damage and / or misalignment of the bearing during assembly is reduced. In some embodiments, the shield is also configured to provide an additional flux path in the electromagnetic circuit within the coupling, improving flux transfer within the device. In some embodiments, the shield may also deform in the presence of magnetic flux and / or as a result of spring force to reduce the size of the opening to the bearing and improve sealing of the bearing.

[0011] These and other aspects, features, details, utilities, and advantages of the present invention will become apparent from a reading of the following detailed description and claims, and from a review of the accompanying drawings which illustrate, by way of example, features of the invention.

[0012]

[0013]

[0014]

[0015]

[0016] [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 illustrates a cross-sectional view of one embodiment of a rotary coupling. [Figure 2] FIG. 2 is an enlarged view of a portion of the rotary coupling device of FIG. 1. [Figure 3] FIG. 3 is a perspective view of a bearing shield of the rotary coupling device shown in FIGS. [Figure 4] FIG. 3 is a perspective view of a bearing shield of the rotary coupling device shown in FIGS. [Figure 5] FIG. 10 is a partial cross-sectional view of an alternative embodiment of a rotary coupling. [Figure 6] FIG. 10 is a partial cross-sectional view of an alternative embodiment of a rotary coupling. [Figure 7] FIG. 10 is a partial cross-sectional view of an alternative embodiment of a rotary coupling. [Figure 8] FIG. 10 is a partial cross-sectional view of an alternative embodiment of a rotary coupling. [Figure 9] FIG. 10 is a partial cross-sectional view of an alternative embodiment of a rotary coupling. [Figure 10] FIG. 10 is a partial cross-sectional view of an alternative embodiment of a rotary coupling. [Figure 11] FIG. 10 is a partial cross-sectional view of an alternative embodiment of a rotary coupling. [Figure 12] FIG. 10 is a cross-sectional view of another alternative embodiment of a rotary coupling. [Figure 13]10 is a partial cross-sectional view of an additional alternative embodiment of a rotary coupling; [Figure 14] 10 is a partial cross-sectional view of an additional alternative embodiment of a rotary coupling; [Figure 15] 10 is a partial cross-sectional view of an additional alternative embodiment of a rotary coupling. DETAILED DESCRIPTION OF THE INVENTION

[0018] Referring now to the drawings, where like reference numerals are used to identify identical components in the various views, FIG. 1 illustrates a rotary coupling device 20 according to one embodiment of the present invention. The device 20 functions as a clutch to selectively transfer torque between a shaft 22 and another device (not shown). The device 20 also functions as a brake when torque is not being transferred. The device 20 may be configured for use in a riding lawn mower or similar device. However, those skilled in the art will appreciate that the device 20 may be used in a wide variety of applications requiring a clutch and / or brake. The device 20 may include a hub assembly 24, bearings 26, 28, an electromagnet 30, an armature 32, a spring 34, a brake plate 36, and a torque transfer member 38. In accordance with the present teachings, the coupling 20 further includes a bearing shield 40.

[0019] The shaft 22 may function as an input shaft—transmitting torque from one device (not shown) and extending from that device through the coupling device 20 to another device (not shown). Alternatively, the shaft 22 may function as an output shaft—receiving torque from another device (not shown) through the coupling device 20 and transmitting that torque to the device (not shown) through which the shaft 22 extends. The shaft 22 may be made from conventional metals and metal alloys and may be solid or tubular. The shaft 22 is centered about an axis of rotation 42 and, when functioning as an input shaft, may be driven by an engine, electric motor, or other conventional power source. In the embodiment shown, the shaft 22 is inserted into the device 20 on the opposite side of the device 20 from the torque-transmitting member 38 ("standard mount").

[0020] Hub assembly 24 is provided for positioning and orienting other components of apparatus 20 and selectively engages armature 32 to provide a means for transferring torque between shaft 22 and member 38. Assembly 24 may include rotor hub 44, rotor disk 46, and spacers 48, 50.

[0021] The rotor hub 44 is coupled to the shaft 22 for rotation therewith. The rotor hub 44 may be fabricated from conventional metals and metal alloys. The rotor hub 44 may be tubular, define a central bore through which the shaft 22 extends, and be disposed about and centered on the shaft 42. The rotor hub 44 may define an axially extending keyway (not shown) that is complementary shaped to and configured to receive a key (not shown) in the shaft 22. Alternatively, the rotor hub 44 may be shaped with an integral radially extending key configured to be received in a keyway in the shaft 22. At either axial end, the rotor hub 44 defines a shoulder that abuts the inner race of the bearings 26, 28 on one axial side of each bearing 26, 28 to support the bearings 26, 28. Additionally, rotor hub 44 may define one or more notches or protrusions located on either axial end surface of rotor hub 44 configured to engage corresponding notches or protrusions in spacers 48, 50, as described in more detail in U.S. Pat. No. 7,527,134, the disclosure of which is incorporated herein by reference in its entirety.

[0022] The rotor disk 46 extends radially outward from the rotor hub 44 and defines a clutch-engagement surface facing the armature 32. The rotor disk 46 is coupled to the rotor hub 44 by a press-fit relationship including, for example, a plurality of complementary protrusions and indentations. As is known in the art, the rotor disk 46 may include a plurality of radially spaced rows of angularly spaced arcuate slots (not shown). When the electromagnet 30 is energized, the slots transmit magnetic flux back and forth across the air gap between the rotor disk 46 and the armature 32, enabling high-torque engagement between the rotor disk 46 and the armature 32. For purposes described below, the rotor disk 46 defines an axially extending outer strut 52 at its outer diameter.

[0023] A spacer 48 is provided to support the bearing 26 and electromagnet 30 in assembled relationship with the other components of the apparatus 20 and may be fabricated from conventional materials, including powdered metal. The spacer 48 is disposed about, and may be centered on, the axis 42 and is generally cylindrical. The inner diameter of the spacer 48 is sized to receive the shaft 22. The outer diameter of the spacer 48 varies to define a shoulder configured to face the inner race of the bearing 26 on the opposite side of the bearing 26 relative to the rotor hub 44, such that the bearing 26 is disposed between the opposing shoulders defined on the spacer 48 and the rotor hub 44. The spacer 48 is disposed radially inward of the electromagnet 30, and the radially outermost surface of the spacer 48 is radially separated from the electromagnet 30 by an air gap 54 that is axially aligned with the bearing 26 on its outboard side. The spacer 48 may further define one or more axially protruding protrusions or indentations on the axial end face of the spacer 48 that are received within or configured to receive corresponding indentations or protrusions on the axial end face of the rotor hub 44, respectively, to rotatably couple the spacer 48 and the rotor hub 44.

[0024] The spacer 50 is provided to support the bearing 28 and torque transmission member 38 in assembled relationship with the other components of the apparatus 20 and may be made from conventional materials, including powder metal. The spacer 50 may have a lower magnetic permeability than the rotor hub 44, rotor disk 46, electromagnet 30, and armature 32 and may be made from, for example, a non-ferromagnetic material. The spacer 50 may be disposed about and centered on the axis 42 and may be generally cylindrical. The spacer 50 is configured to receive a fastener (not shown) extending through the spacer 50 and into the shaft 22. Like the spacer 50, the fastener may have a lower magnetic permeability than the rotor hub 44, rotor disk 46, electromagnet 30, and armature 32 and may be made from, for example, a non-ferromagnetic material, such as selected stainless steel. The spacer 50 may define a head 56 at one axial end, the head having a plurality of flats that enable the spacer 50 to be secured during application of torque to the fastener. Spacer 50 may further define a body 58 extending axially from head portion 56. Body 58 has a generally cylindrical outer surface upon which bearing 28 may rest between opposing shoulders defined on rotor hub 44 and spacer 50. Spacer 50 may further define one or more axially extending protrusions or indentations on an axial end surface of body 58 that are received in, or are configured to receive, corresponding indentations or protrusions defined on the axial end surface of rotor hub 44, respectively, to rotatably couple spacer 50 and rotor hub 44.

[0025] Bearings 26 are provided to allow rotation of rotor hub 44 and spacer 48 relative to electromagnet 30. Bearings 26 are conventional in the industry. The inner race of bearing 26 is supported by rotor hub 44 and spacer 48 and may abut opposing shoulders defined on rotor hub 44 and spacer 48. The outer race of bearing 26 supports electromagnet 30.

[0026] Bearings 28 are provided to permit rotation of torque transmitting member 38 relative to input shaft 22, rotor hub 44, and spacer 50. Bearings 28 are conventional in the industry. The inner race of bearing 28 is supported by and bears against opposed shoulders defined on rotor hub 44 and spacer 50. The outer race of bearing 28 supports torque transmitting member 38.

[0027] The electromagnet 30 establishes an electromagnetic circuit between the electromagnet 30, the armature 32, the rotor hub 44, and the rotor disk 46, causing movement of the armature 32 into engagement with the rotor disk 46 and transmitting torque between the shaft 22 and the torque transmitting member 38. The electromagnet 30 is disposed on one side of the rotor disk 46 opposite the armature 32 and includes a field shell or housing 60 and a conduction assembly 62.

[0028] A housing 60 is provided to house a transmission assembly 62. The housing 60 also forms part of the electromagnetic circuit that causes selective engagement between the armature 32 and the rotor disk 46. The housing 60 may be made from a variety of conventional metals and metal alloys, including steel. The housing 60 is cylindrical and disposed about, and may be centered on, the shaft 42, and is supported by the outer race of the bearing 26. The housing 60 is fixed against rotation. The housing 60 is generally U-shaped in cross section and includes radially inner and radially outer annular members 64, 66.

[0029] The inner member 64 rests against the outer race of the bearing 26. The inboard axial end of the inner member 64 is disposed radially outward of and spaced from the rotor hub 44 and is axially aligned with and spaced from the rotor disk 46. The member 64 defines an inner strut 68 that is spaced from and extends axially radially inward from the outer strut 52 of the rotor disk 46.

[0030] The outer member 66 is connected to and supported by the inner member 64. The outer member 66 defines an end wall 70, an axially extending outer strut 72, and a flange 74. The end wall 70 extends radially outward from the member 64. The strut 72 is integral with the end wall 70 and extends axially therefrom. The strut 72 is spaced radially outward from the struts 52 of the rotor disk 46. The flange 74 is integral with the strut 72 at an end of the strut 72 opposite the end wall 70 and extends radially outward therefrom. The flange 74 extends along at least a portion of the circumference of the strut 72.

[0031] A conduction assembly 62 is provided for establishing a magnetic circuit between the housing 60, armature 32, rotor hub 44, and rotor disk 46 of the electromagnet 30, causing movement of the armature 32 that engages the rotor disk 46 and transmits torque between the shaft 22 and the torque transmitting member 38. The conduction assembly 62 may be generally annular and may be disposed within the housing 60 around and centered on the axis 42. In particular, the assembly 62 is disposed between an inner post 68 and an outer post 72 of the housing 60. The assembly 62 includes a conductor 76 and a conductor shell 78.

[0032] Conductor 76 may comprise a conventional copper coil, although other known conductors may alternatively be used. Conductor 76 may be electrically connected to a power supply (not shown), such as a battery. When conductor 76 is energized, an electromagnetic circuit is formed between housing 60, armature 32, rotor hub 44, and rotor disk 46 of electromagnet 30. Magnetic flux flows from outer strut 72 of outer member 66 of housing 60 across the air gap to outer strut 52 of rotor disk 46. The flux then travels back and forth between rotor disk 46 and armature 32 across the air gap between them. The flux then flows from rotor disk 46 to inner member 64 of housing 60 and to rotor hub 44. Flux may flow from rotor hub 44 to inner member 64 of housing 60 along several paths. A portion of the flux flows directly across the air gap from rotor hub 44 to inner member 64 of housing 60. According to one aspect of the teachings disclosed herein, as described in more detail below, another portion of the flux may flow indirectly from the rotor hub 44 through the spacer 48 and the shield 40 to the inner member 64 of the housing 60 radially inward of the bearing 26.

[0033] A conductor shell 78 is provided to house the conductors 76 and is used to mount the conductors 76 within the housing 60 of the electromagnet 30. The conductor shell 78 may be molded from conventional plastic. The conductor shell 78 may include an integral terminal connector 80, through which the conductors 76 may be electrically connected to a power source. The conductor shell 78 may also define one or more protrusions sized to be received in recesses in the end wall 70 of the member 66 of the housing 60 to prevent rotation of the conduction assembly 62. As described in commonly assigned, pending U.S. Patent No. 7,975,818 (the disclosure of which is incorporated herein by reference in its entirety), the conductor shell 78 may include a radially outwardly extending flange disposed proximate the outer post 72 of the housing 60 and attached to the member 66 of the housing 60 at multiple points.

[0034] The armature 32 is provided to transmit torque between the rotor disk 46 and the torque transmission member 38. The armature 32 may be fabricated from various conventional metals and metal alloys, including steel. The armature 32 may be annular in structure and may be disposed about and centered on the axis 42. The armature 32 is disposed on one side of the rotor disk 46 opposite the electromagnet 30 and defines a clutch-engagement surface facing the rotor disk 46. The armature 32 is axially spaced from the rotor disk 46 by an air gap. Like the rotor disk 46, the armature 32 may include multiple radially spaced rows of angularly spaced arcuate slots (not shown) that facilitate the passage of magnetic flux back and forth between the rotor disk 46 and the armature 32 upon energization of the transmission assembly 62. The armature 32 is coupled to the transmission member 38. In particular, the armature 32 may be coupled to a torque transmitting member 38 by a plurality of leaf springs 34 .

[0035] The spring 34 transmits drive and braking torque between the armature 32 and the torque transmitting member 38 and allows axial movement of the armature 32 relative to the member 38 toward and away from the rotor disk 46. The spring 34 may be made from stainless steel and is connected at one end to the armature 32 and at the opposite end to the member 38 using conventional fasteners, such as rivets, screws, bolts, or pins.

[0036] The brake plate 36 provides a braking surface for engagement by the armature 32 to brake the torque transmitting member 38. The brake plate 36 may be made from conventional materials having relatively high magnetic permeability, including conventional metals and metal alloys, such as steel. The brake plate 36 extends around at least a portion of the circumference of the device 20, preferably only a portion of the circumference of the device 20, and is coupled to the housing 60 of the electromagnet 30. In particular, the brake plate 36 is coupled to a flange 74 of a member 66 of the housing 60 and suspended therefrom using one or more fasteners 82. The fasteners 82 may be made from one or more materials (including non-magnetic materials) having a lower magnetic permeability than the armature 32, rotor hub, rotor disk 46, and housing 60 of the electromagnet 30, reducing or eliminating flux transfer between the brake plate 36 and the housing 60, thereby facilitating clutch engagement when the transmission assembly 62 is energized. The brake plate 36 may be axially spaced from the flange 74 of the housing 60 using one or more spacers 84 or shims, such as those described in commonly assigned U.S. Pat. No. 8,123,012, the disclosure of which is incorporated herein by reference in its entirety. The spacers 84 allow adjustment of the position of the brake plate 36 to compensate for wear on the clutch-engaging and brake-engaging surfaces of the armature 32 and rotor disk 46, respectively. The spacers 84 may include bores through which the fasteners 82 extend. The spacers 84 may likewise be made of one or more materials (including non-magnetic materials) having a relatively lower magnetic permeability than the armature 32, rotor hub 44, rotor disk 46, and housing 60 of the electromagnet 30, reducing or eliminating flux transfer between the brake plate 36 and housing 60. For example, with reference to commonly assigned U.S. Pat. No. 7,732,959 (the disclosure of which is incorporated herein by reference in its entirety), plate 36 may house one or more magnets (not shown), thereby forming part of a magnetic circuit with armature 32 and the magnets to assist spring 34 in drawing armature 32 into engagement with brake plate 36 and providing a braking torque to torque transmitting member 38.

[0037] Torque transmitting member 38 transfers torque between shaft 22 and another device, such as a lawnmower blade. Member 38 is connected to armature 32 through leaf spring 34 and is supported for rotation on the outer race of bearing 28. Member 38 may be disposed about and centered on axis 42. In the embodiment shown, member 38 includes a pulley around which a belt may be wrapped to connect member 38 to a driving or driven device. However, it should be understood that member 38 may take a variety of different forms.

[0038] The shield 40 is provided to prevent contaminants, such as fluids or dust, from damaging the bearing 26. In particular, the shield 40 prevents contaminants from passing from the external environment through the air gap 54 to the bearing 26. The shield 40 may be made from a variety of materials. In some embodiments, the shield 40 is made from a material having a relatively high magnetic permeability, such as a ferromagnetic material, such that the shield 40 passes flux from the spacer 48 to one of the members 64, 66 of the housing 60 of the electromagnet 30. The shield 40 may be annular in shape and may be disposed about and centered on the axis 42.

[0039] 2-4, the shield 40 includes a radially innermost portion 86, which extends generally radially and defines a fixed end 88 of the shield 40. The portion 86 and the fixed end 88 are axially sandwiched between the bearing 26 and the spacer 48, specifically between the inner race of the bearing 26 and the opposing radially extending surfaces of the spacer 48. During assembly of the device 20 and before providing the device 20 to an end user, the shield 40 is positioned to align the portion 86 of the shield 40 with the inner race of the bearing 26, after which the spacer 48 is moved along the axis 42 and coupled to the rotor hub 44, thereby securing the portion 86 of the shield 40 between the inner race of the bearing 26 and the spacer 48. In this manner, movement of the fixed end 88 of the shield 40 is restricted. The shield 40 further includes a portion 90, which extends generally axially and has an inboard axial end extending from the radially outer end of the portion 86. Portion 90 is disposed within air gap 54 and extends across its entire axial width. Shield 40 further includes portion 92, which extends generally radially and has a radially inner end extending from an axially outboard end of portion 90 opposite an axially inboard end of portion 90 joined to portion 86. Portion 92 is therefore axially spaced from portion 86. Portion 92 is axially aligned with air gap gap 54 and extends across its entire radial length. Shield 40 further includes a radially outermost portion 94, which extends generally axially and has an axially outboard end extending from a radially outer end of portion 92 opposite a radially inner end of portion 92 joined to portion 90. Portion 94 is therefore radially spaced from portion 90. Portion 94 defines a free end 96 of shield 40 configured to engage electromagnet 30. In the embodiment shown, the free end 96 is configured to engage the member 66 of the housing 60 of the electromagnet 30. However, it should be understood that the free end 96 may be configured to engage the electromagnet 30 in a variety of different positions.As mentioned above, in some embodiments, the shield 40 may be made of a material, such as a ferromagnetic material, that allows magnetic flux to travel from the rotor hub 44 to the electromagnet 30 (through the spacer 48 and the shield 40) when the electromagnet 30 is energized. The flow of magnetic flux may also cause deformation of the shield 40 and improved sealing of the bearing 26. In particular, the shield 40 has a normal or unstressed state when the electromagnet 30 is not energized. In this state, the portion 94 and free end 96 of the shield 40 may be axially spaced apart from the electromagnet 30 (especially when the surfaces of the shield 40 and the electromagnet 30 are worn with use). When the electromagnet 30 is energized, the shield 40 assumes a deformed or stressed state. In this condition, magnetic flux traveling through shield 40 to housing 60 of electromagnet 30 creates a magnetic attraction between shield 40 and housing 60, causing portion 94 and free end 96 of shield 40 to move toward, and preferably contact, housing 60 of electromagnet 30, thereby reducing or eliminating any gap between shield 40 and housing 60 of electromagnet 30 and further reducing the likelihood of contaminants reaching air gap 54 and bearing 26.

[0040] 5, an alternative embodiment rotary coupling device 120 is shown. Device 120 is substantially similar to device 20 described above. Device 120 differs from device 20 in that device 120 omits the spacer 48 found in hub assembly 24 of device 20 and instead integrates rotor hub 44 and spacer 48 of device 20 into a unitary (one-piece) rotor hub 144. As a result, portion 86 and fixed end 88 of shield 40 are axially sandwiched between bearing 26 and rotor hub 144, specifically between the inner race of bearing 26 and opposing radially extending surfaces of rotor hub 144.

[0041] Referring now to FIG. 6 , another alternative embodiment of a rotary coupling device 220 is shown. Device 220 is substantially similar to device 20 described above. Device 220 differs from device 20 in that device 220 includes a shield 240 that is oriented differently from the orientation of shield 40 in device 20. Again, shield 240 is provided to prevent contaminants, such as fluids or dust, from damaging bearing 26. In particular, shield 240 prevents contaminants from passing from the external environment through air gap 54 to bearing 26. Shield 240 may be made from a variety of materials. In some embodiments, shield 240 is made from a material with a relatively high magnetic permeability, such as a ferromagnetic material, such that shield 240 passes flux from spacer 48 to one of members 64, 66 of housing 60 of electromagnet 30. Shield 240 may be annular in shape and may be disposed about and centered on axis 42.

[0042] Shield 240 includes a radially outermost portion 286 that extends generally radially and defines a fixed end 288 of shield 240. Portion 286 and fixed end 288 are axially sandwiched between bearing 26 and electromagnet 30, specifically, between the outer race of bearing 26 and opposing radially extending surfaces of electromagnet 30. During assembly of device 220 and before providing device 220 to an end user, shield 240 is positioned to align portion 286 of shield 240 with the outer race of bearing 26, after which electromagnet 30 is moved along axis 42 and positioned relative to rotor hub 44, thereby securing portion 286 of shield 240 between the outer race of bearing 26 and electromagnet 30. In this manner, movement of fixed end 288 of shield 240 is restricted. Shield 240 further includes portion 290, which extends generally axially and has an inboard axial end extending from the radially inner end of portion 286. Portion 290 is disposed within gap gap 54 and extends throughout its axial width. Shield 240 further includes portion 292, which extends generally radially and has a radially outer end extending from the axially outboard end of portion 290 opposite the axially inboard end of portion 290 joined to portion 286. Portion 292 is therefore axially spaced from portion 286. Portion 292 is axially aligned with gap gap 54 and extends throughout its radial length. Shield 240 further includes a radially innermost portion 294 that extends generally axially and has an axially outboard end that extends from a radially inner end of portion 292 opposite the radially outer end of portion 292 joined to portion 290. Portion 294 is thus radially spaced from portion 290. Portion 294 defines a free end 296 of shield 240 that is configured to engage spacer 48. As mentioned above, in some embodiments, shield 240 may be made from a material, such as a ferromagnetic material, that allows magnetic flux to travel from rotor hub 44 to electromagnet 30 (through spacer 48 and shield 240) when electromagnet 30 is energized.The flow of magnetic flux can also cause deformation of the shield 240 and improved sealing of the bearing 26. In particular, the shield 240 has a normal or unstressed state when the electromagnet 30 is not energized. In this state, the portion 294 and free end 296 of the shield 240 can be axially spaced apart from the spacer 48 (especially when the surfaces of the shield 240 and the spacer 48 are worn after use). When the electromagnet 30 is energized, the shield 240 assumes a deformed or stressed state. In this state, magnetic flux moving between the shield 240 and the spacer 48 creates a magnetic attraction between the shield 240 and the spacer 48, forcing the portion 294 and free end 296 of the shield 240 toward, and preferably into contact with, the spacer 48, thereby reducing or eliminating any gap between the shield 240 and the spacer 48 and further reducing the likelihood of contaminants reaching the air gap 54 and the bearing 26.

[0043] 7, another alternative embodiment rotary coupling device 320 is shown. Device 320 is substantially similar to device 220 described above. Device 320 differs from device 220 in that device 220 omits spacer 48 found in hub assembly 24 of device 20 and instead integrates rotor hub 44 and spacer 48 of device 20 into a unitary (one-piece) rotor hub 344. As a result, portion 294 and free end 296 of shield 320 are configured to engage a surface of rotor hub 344.

[0044] Referring now to FIG. 8 , another alternative embodiment of a rotary coupling device 420 is shown. Device 420 is substantially similar to device 20 described above. Device 420 differs from device 20 in that device 420 includes a different embodiment of a bearing shield 440. Again, shield 440 is provided to prevent contaminants, such as fluids or dust, from damaging bearing 26. In particular, shield 440 prevents contaminants from passing from the external environment through air gap 54 to bearing 26. Shield 440 may be made from a variety of materials. In some embodiments, shield 440 is made from a material with a relatively high magnetic permeability, such as a ferromagnetic material, such that shield 440 transmits flux from spacer 48 to member 64 of housing 60 of electromagnet 30. Shield 440 may be annular in shape and may be disposed about and centered on shaft 42.

[0045] Shield 440 includes a radially innermost portion 486 that extends generally radially and defines a fixed end 488 of shield 440. Portion 486 and fixed end 488 are axially sandwiched between bearing 26 and spacer 48, specifically, between the inner race of bearing 26 and opposing radially extending surfaces of spacer 48. During assembly of device 420 and before providing device 420 to an end user, shield 440 is positioned to align portion 486 of shield 440 with the inner race of bearing 26, after which spacer 48 is moved along axis 42 and coupled to rotor hub 44, thereby securing portion 486 of shield 440 between the inner race of bearing 26 and spacer 48. In this manner, movement of fixed end 488 of shield 440 is restricted. The shield 440 further includes a portion 490 that extends generally axially and has an inboard axial end that extends from the radially outer end of the portion 486. The portion 490 is disposed within the gap gap 54 and extends through at least a portion of its axial width, and may extend through the entire axial width of the gap gap 54. The shield 440 further includes a portion 492 that extends radially outward and axially inboard from the portion 490. The radially inner end of the portion 492 extends from the axially outboard end of the portion 490 opposite the axially inboard end of the portion 490 joined to the portion 486. The radially inner end of the portion 492 meets the axially outboard end of the portion 490 at an acute angle. The shield 440 further includes a radially outermost portion 494 that extends radially outward and axially outboard from the portion 492. A radially inner end of portion 494 extends from a radially outer end of portion 492 opposite the radially inner end of portion 492 joined to portion 490. The radially inner end of portion 494 meets the radially outer end of portion 492 at an acute angle. Portions 492, 494 are at least partially disposed within air gap 54, and together, portions 492, 494 extend the entire radial length of air gap 54. Portion 494 defines a free end 496 of shield 440, which is configured to engage electromagnet 30.In particular, the radially outer end of portion 494 is configured to engage the radially inner surface of member 64 of housing 60 of electromagnet 30. Due to the configuration of shield 440, shield 440 is configured to deform from a normal or unstressed state before assembly to a deformed or stressed state after assembly in which free end 496 applies a spring force to the surface of electromagnet 30. In some embodiments, shield 440 may again be made from a material, such as a ferromagnetic material, that allows magnetic flux to travel from rotor hub 44 to electromagnet 30 (through spacer 48 and shield 440) when electromagnet 30 is energized. The flow of magnetic flux may also result in improved sealing of bearing 26. In particular, when electromagnet 30 is energized, magnetic flux traveling through shield 440 to housing 60 of electromagnet 30 creates a magnetic attraction between shield 440 and electromagnet 30 that supplements the spring force, creating a stronger engagement between portion 494 and free end 496 and electromagnet 30, further reducing the likelihood of contaminants reaching air gap 54 and bearing 26.

[0046] 9, another alternative embodiment rotary coupling device 520 is shown. Device 520 is substantially similar to device 420 described above. Device 520 differs from device 420 in that device 520 omits the spacer 48 found in hub assembly 24 of device 420 and instead integrates rotor hub 44 and spacer 48 of device 420 into a unitary (one-piece) rotor hub 544. As a result, portion 486 and fixed end 488 of shield 440 are axially sandwiched between bearing 26 and rotor hub 544, specifically, between the inner race of bearing 26 and opposing radially extending surfaces of rotor hub 544.

[0047] Referring now to FIG. 10 , another alternative embodiment of a rotary coupling device 620 is shown. Device 620 is substantially similar to device 420 described above. Device 620 differs from device 420 in that device 620 includes a shield 640 that is oriented differently from the orientation of shield 440 in device 420. Shield 640 is again provided to prevent contaminants, such as fluids or dust, from damaging bearing 26. In particular, shield 640 prevents contaminants from passing from the external environment through air gap 54 to bearing 26. Shield 640 may be made from a variety of materials. In some embodiments, shield 640 is made from a material with a relatively high magnetic permeability, such as a ferromagnetic material, such that shield 640 transmits flux from spacer 48 to member 64 of housing 60 of electromagnet 30. Shield 640 may be annular in shape and may be disposed about and centered on axis 42.

[0048] Shield 640 includes a radially outermost portion 686 that extends generally radially and defines a fixed end 688 of shield 640. Portion 686 and fixed end 688 are axially sandwiched between bearing 26 and electromagnet 30, specifically between opposing radially extending surfaces of the outer race of bearing 26 and member 64 of housing 60 of electromagnet 30. During assembly of device 620, and before providing device 620 to an end user, shield 640 is positioned to align portion 686 of shield 640 with the outer race of bearing 26, after which electromagnet 30 is moved along axis 42 and coupled to rotor hub 44, thereby securing portion 686 of shield 640 between the outer race of bearing 26 and electromagnet 30. In this manner, movement of fixed end 688 of shield 640 is restricted. Shield 640 further includes portion 690, which extends generally axially and has an inboard axial end extending from the radially inner end of portion 686. Portion 690 is disposed within gap gap 54 and extends through at least a portion of its axial width, and may extend through the entire axial width of gap gap 54. Shield 640 further includes portion 692, which extends radially inward and axially inboard from portion 690. The radially outer end of portion 692 extends from an axially outboard end of portion 690 opposite the axially inboard end of portion 690 joined to portion 686. The radially outer end of portion 692 meets the axially outboard end of portion 690 at an acute angle. Shield 640 further includes a radially innermost portion 694 that extends radially inward and axially outward from portion 692. The radially outer end of portion 694 extends from a radially inner end of portion 692 opposite the radially outer end of portion 692 joined to portion 690. The radially outer end of portion 694 intersects with the radially inner end of portion 692 at an acute angle. Portion 494 defines a free end 496 of shield 440, which is configured to engage electromagnet 30. Portions 692, 694 are at least partially disposed within air gap 54, and together, portions 692, 694 extend the entire radial length of air gap gap 54.Portion 694 defines a free end 696 of shield 640, which is configured to engage spacer 48. In particular, a radially inner end of portion 694 is configured to engage a radially outer surface of spacer 48. Due to the configuration of shield 640, shield 640 is configured to deform from a normal or unstressed state before assembly to a deformed or stressed state after assembly in which free end 696 applies a spring force against the surface of spacer 48. In some embodiments, shield 640 may again be fabricated from a material, such as a ferromagnetic material, that allows magnetic flux to travel from rotor hub 44 to electromagnet 30 (through spacer 48 and shield 640) when electromagnet 30 is energized. The flow of magnetic flux may also result in improved sealing of bearing 26. In particular, when electromagnet 30 is energized, magnetic flux moving between spacer 48 and shield 640 creates a magnetic attraction between spacer 48 and shield 640 that supplements the spring force, creating a stronger engagement between portion 694 and free end 696 and spacer 48, further reducing the likelihood of contaminants reaching air gap 54 and bearing 26.

[0049] 11 , another alternative embodiment rotary coupling device 720 is shown. Device 720 is substantially similar to device 620 described above. Device 720 differs from device 620 in that device 720 omits spacer 48 found in hub assembly 24 of device 620 and instead integrates the rotor hub and spacer of device 620 into a unitary (one-piece) rotor hub 744. As a result, portion 694 and free end 696 of shield 640 are configured to engage the surface of rotor hub 744.

[0050] Referring now to FIG. 12 , another alternative embodiment of a rotary coupling device 820 is shown. The device 820 is substantially similar to the device 20 described above. The device 820 differs from the device 20 in that the device 820 includes a different embodiment of a bearing shield 840. The shield 840 is provided to prevent contaminants, such as fluids or dust, from damaging the bearing 26. In particular, the shield 840 prevents contaminants from passing from the external environment through the air gap 54 to the bearing 26. The shield 840 may be made from a variety of materials. In some embodiments, the shield 840 is made from a material having a relatively high magnetic permeability, such as a ferromagnetic material, such that the shield 840 passes flux from the spacer 48 to one of the members 64, 66 of the housing 60 of the electromagnet 30. The shield 840 may be annular in shape and may be disposed about and centered on the axis 42.

[0051] Shield 840 includes a radially outermost portion 886, which extends generally axially and defines a fixed end 888 that is coupled to electromagnet 30. During assembly of device 820, and before providing device 820 to an end user, fixed end 888 may be affixed to electromagnet 30 in a variety of ways, including by mechanical deformation (e.g., staking), adhesive, brazing, etc. In the illustrated embodiment, fixed end 888 is coupled to member 66 of housing 60 of electromagnet 30. However, it should be understood that fixed end 888 may be coupled to any surface of electromagnet 30, including a surface within air gap 54. Shield 840 further includes portion 892, which extends generally radially from portion 886. The radially outermost end of portion 892 is joined to an axially outboard end of portion 886. Portion 892 is axially aligned with air gap 54 and extends its entire radial length. Shield 840 further includes portion 894, which extends generally axially from portion 892. Thus, portion 894 is radially spaced from portion 886. An axially outboard end of portion 894 is coupled to a radially inner end of portion 892. An axially inboard end of portion 894 defines a free end 896 of shield 840, which is configured to engage with spacer 48, in the illustrated embodiment, a radially extending surface of spacer 48. As mentioned above, in some embodiments, shield 840 may be made of a material, such as a ferromagnetic material, that allows magnetic flux to travel from rotor hub 44 to electromagnet 30 (through spacer 48 and shield 840) when electromagnet 30 is energized. The flow of magnetic flux may further result in deformation of shield 840 and improved sealing of bearing 26. In particular, shield 840 has a normal or unstressed state when electromagnet 30 is not energized. In this state, portion 894 and free end 896 of shield 840 may be axially spaced apart from spacer 48 (especially when the surfaces of shield 840 and spacer 48 are worn after use). When electromagnet 30 is energized, shield 840 assumes a deformed or stressed state.In this condition, magnetic flux traveling between spacer 48 and shield 840 creates a magnetic attraction between spacer 48 and shield 840, causing portion 894 and free end 896 of shield 840 to move toward, and preferably contact, spacer 48, thereby reducing or eliminating any gap between shield 840 and spacer 48 and further reducing the likelihood of contaminants reaching air gap 54 and bearing 26. In the embodiment shown, free end 896 of shield 840 engages spacer 48, but again, it should be understood that in alternative embodiments, separate spacer 48 may be omitted and integrated into rotor hub 44 as a unitary (one-piece) body such that free end 896 of shield 840 engages a surface of rotor hub 44.

[0052] Referring now to FIG. 13 , another alternative embodiment of a rotary coupling device 920 is shown. Device 920 is substantially similar to device 820 described above. Device 920 differs from device 820 in that device 920 includes a different embodiment of a bearing shield 940. Shield 940 is provided to prevent contaminants, such as fluids or dust, from damaging bearing 26. In particular, shield 940 prevents contaminants from passing from the external environment through air gap 54 to bearing 26. Shield 940 may be made from a variety of materials. In some embodiments, shield 940 is made from a material with a relatively high magnetic permeability, such as a ferromagnetic material, such that shield 940 transmits flux from spacer 48 to one of members 64, 66 of housing 60 of electromagnet 30. Shield 940 may be annular in shape and may be disposed about and centered on shaft 42.

[0053] Shield 940 includes a radially outermost portion 986, which extends generally axially and defines a fixed end 988 that is coupled to electromagnet 30. During assembly of device 920, and before providing device 920 to an end user, fixed end 988 may be affixed to electromagnet 30 in a variety of ways, including mechanical deformation (e.g., crimping), adhesive, brazing, etc. In the illustrated embodiment, fixed end 988 is coupled to member 66 of housing 60 of electromagnet 30. However, it should be understood that fixed end 988 may be coupled to any surface of electromagnet 30, including a surface within air gap 54. Shield 940 further includes portion 992, which extends generally radially from portion 986. The radially outermost end of portion 992 is joined to the axially outboard end of portion 986. Shield 940 further includes portion 994, which extends radially inward and axially inboard from portion 992. Thus, portion 994 is radially spaced from portion 986. The radially outer and axially outboard ends of portion 994 are coupled to the radially inner end of portion 992. The radially inner and axially inboard ends of portion 994 define a free end 996 of shield 940, which is configured to engage spacer 48 and, in the illustrated embodiment, an axially extending surface of spacer 48 within gap gap 54. Portion 994 is partially disposed within gap gap 54. Portions 992 and / or 994 are axially aligned with gap gap 54 and extend over its entire radial length. Due to the configuration of shield 940, shield 940 is configured to deform from a normal or unstressed state before assembly to a deformed or stressed state after assembly (and particularly when spacer 48 is advanced axially inward along axis 42) in which free end 996 applies a spring force to a surface of spacer 48. In some embodiments, shield 940 may again be made from a material, such as a ferromagnetic material, that allows magnetic flux to travel from rotor hub 44 to electromagnet 30 (through spacer 48 and shield 940) when electromagnet 30 is energized. The flow of magnetic flux may also result in improved sealing of bearing 26.In particular, when electromagnet 30 is energized, magnetic flux traveling between spacer 48 and shield 940 creates a magnetic attraction between spacer 48 and shield 940 that supplements the spring force and creates a stronger engagement between portion 994 and free end 996 and spacer 48, further reducing the likelihood of contaminants reaching air gap 54 and bearing 26. In the embodiment shown, free end 996 of shield 940 engages spacer 48, but again, it should be understood that in alternative embodiments, separate spacer 48 may be omitted and integrated into rotor hub 44 as a unitary (one-piece) body such that free end 996 of shield 940 engages a surface of rotor hub 44.

[0054] Referring now to FIG. 14 , another alternative embodiment rotary coupling device 1020 is shown. The device 1020 is substantially similar to the device 20 described above. The device 1020 differs from the device 20 in that the device 1020 omits the separate bearing shield 40 and instead integrates a bearing shield 1040 into a spacer 1048 within a unitary (one-piece) body. In particular, the shield 1040 is defined by a radially outwardly extending flange formed at an axially outboard end of the spacer 1048 and defining a radially inner fixed end 1086 and a radially outer free end 1088. The shield 1040 is provided to prevent contaminants, such as fluids or dust, from damaging the bearing 26. In particular, the shield 1040 prevents contaminants from passing from the external environment through the air gap 54 to the bearing 26. The shield 1040 extends the entire radial length of the air gap 54. The spacer 1048 and the shield 1040 may again be made of a material, such as a ferromagnetic material, that allows magnetic flux to travel from the rotor hub 44 to the electromagnet 30 (through the spacer 1048 and the shield 1040) when the electromagnet 30 is energized. The flow of magnetic flux may also result in improved sealing of the bearing 26. In particular, the shield 1040 may be thin enough to allow the shield 1040 to deform from a normal or unstressed state when the electromagnet 30 is not energized to a deformed or stressed state when the electromagnet is energized. In the normal or unstressed state, the free end 1088 may be spaced from the electromagnet 30 (especially when the surfaces of the shield 1040 and the electromagnet 30 are worn after use). Under stress, magnetic flux traveling through the shield 1040 to the housing 60 of the electromagnet 30 creates a magnetic attraction between the shield 1040 and the housing 60, causing the free end 1088 of the shield 1040 to move toward, and preferably contact, the housing 60 of the electromagnet 30, thereby reducing or eliminating any gap between the shield 1040 and the housing 60 of the electromagnet 30 and further reducing the likelihood of contaminants reaching the air gap 54 and the bearing 26.In the embodiment shown, the shield 1040 is formed as part of the spacer 1048, but again, it should be understood that in alternative embodiments, the separate spacer 1048 may be omitted and integrated into the rotor hub 44 as a unitary (one-piece) body, with the shield 1040 instead forming part of the rotor hub 44.

[0055] Referring now to FIG. 15 , another alternative embodiment rotary coupling device 1120 is shown. Device 1120 is substantially similar to device 20 described above. Device 1120 differs from device 20 in that device 1120 omits the separate bearing shield 40 and instead integrates a bearing shield 1140 into member 1164 of housing 60 of electromagnet 30 within a unitary (one-piece) body. In particular, shield 1140 is defined by a radially inwardly extending flange formed at an axially outboard end of member 1164 and defining a radially outer fixed end 1186 and a radially inner free end 1188. Shield 1140 is provided to prevent contaminants, such as fluids or dust, from damaging bearing 26. In particular, shield 1140 prevents contaminants from passing from the external environment through air gap 54 to bearing 26. The shield 1140 extends the entire radial length of the air gap 54. The member 1164 and the shield 1140 may again be made of a material, such as a ferromagnetic material, that allows magnetic flux to travel from the rotor hub 44 to the electromagnet 30 (through the spacer 48 and the shield 1140) when the electromagnet 30 is energized. The flow of magnetic flux may also result in improved sealing of the bearing 26. In particular, the shield 1140 may be sufficiently thin to allow the shield 1140 to deform from a normal or unstressed state when the electromagnet 30 is not energized to a deformed or stressed state when the electromagnet is energized. In the normal or unstressed state, the free end 1188 may be spaced from the spacer 48 (especially when the surfaces of the shield 1140 and the spacer 48 are worn after use). Under stress, magnetic flux traveling through the shield 1140 to the spacer 48 creates a magnetic attraction between the shield 1140 and the spacer 48, causing the free end 1188 of the shield 1140 to move toward, and preferably contact, the spacer 48, thereby reducing or eliminating any gap between the shield 1140 and the spacer 48 and further reducing the likelihood of contaminants reaching the air gap 54 and the bearing 26.In the embodiment shown, the free end 1188 of the shield 1140 contacts the spacer 48, but again, it should be understood that in alternative embodiments, the separate spacer 48 may be omitted and integrated into the rotor hub 44 as a unitary (one-piece) body, with the free end 1188 of the shield 1140 instead contacting the rotor hub 44.

[0056] A rotary coupling 20, 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020, or 1120 according to the present teachings provides advantages over conventional couplings. The coupling 20, 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020, or 1120 includes a shield 40, 240, 440, 640, 840, 940, 1040, or 1140 that prevents contaminants, such as fluids and particulate matter, from reaching the bearing 26 of the device 20, 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020, or 1120. Because the fixed end 88, 288, 488, 688, 888, 988, 1086 or 1186 of the shield 40, 240, 440, 640, 840, 940, 1040 or 1140 is coupled to the hub assembly 24 or the electromagnet 30, it may be included as a pre-assembled unit with the device 20, 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020 or 1120, thereby eliminating inconvenience to the end user of the device and the possibility that the end user will forget to install or improperly install the shield 40, 240, 440, 640, 840, 940, 1040 or 1140. Additionally, because the shield 40, 240, 440, 640, 840, 940, 1040, or 1140 is not directly attached to the bearing race, potential damage and / or misalignment of the bearing 26 during assembly is reduced. In some embodiments, the shield 40, 240, 440, 640, 840, 940, 1040, or 1140 is also configured to provide an additional flux path in the electromagnetic circuit within the coupling device 20, 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020, or 1120 to improve flux delivery within the device 20, 120, 220, 320, 420, 520, 620, 720, 820, 920, 1020, or 1120. In some embodiments, the shield 40, 240, 440, 640, 840, 940, 1040 or 1140 may also deform in the presence of magnetic flux and / or as a result of spring force to reduce the size of the opening leading to the bearing 26 and improve sealing of the bearing 26.

[0057] While the present invention has been illustrated and described with reference to one or more specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention.

Claims

1. a hub assembly configured to rotate about an axis of rotation, the hub assembly including a rotor hub disposed about the axis of rotation and configured to receive a shaft, and a rotor disk extending radially outward from the rotor hub; an armature disposed on a first axial side of the rotor disk; an electromagnet disposed on a second axial side of the rotor disk opposite the armature and fixed against rotation; a bearing disposed between the rotor hub and the electromagnet, the hub assembly and the electromagnet being separated by an air gap on an outboard side of the bearing; a shield disposed partially within the air gap and extending across the entire radial length of the air gap, the shield having a fixed end that engages one of the hub assembly and the electromagnet, and a free end opposite the fixed end, the free end configured to engage the other of the hub assembly and the electromagnet; and A rotary coupling device comprising:

2. The rotary coupling of claim 1 , wherein the fixed end of the shield is disposed between the bearing and the one of the hub assembly and the electromagnet.

3. The rotary coupling of claim 2 , wherein the fixed end of the shield is disposed between the bearing and the rotor hub of the hub assembly.

4. 3. The rotary coupling of claim 2, wherein the hub assembly includes a spacer that engages a first axial end of the rotor hub and supports the bearing, the fixed end of the shield being disposed between the bearing and the rotor hub of the hub assembly.

5. The rotary coupling of claim 2 , wherein the fixed end of the shield is disposed between a radially inner race of the bearing and the hub assembly.

6. 6. The rotary coupling of claim 5, wherein the fixed end of the shield is disposed between a radially extending surface of the inner race of the bearing and a radially extending surface of the hub assembly.

7. 3. The rotary coupling of claim 2, wherein the fixed end of the shield is disposed between the radially outer race of the bearing and the electromagnet.

8. 8. The rotary coupling of claim 7, wherein the fixed end of the shield is disposed between a radially extending surface of the outer race of the bearing and a radially extending surface of the electromagnet.

9. The rotary coupling of claim 1 , wherein the shield extends through the entire axial width of the air gap.

10. The rotary coupling of claim 1 , wherein the free end of the shield is located outside the air gap and configured to engage the other radially extending surface of the hub assembly and the electromagnet.

11. The rotary coupling of claim 1 , wherein the free end of the shield is positioned inside the air gap and configured to engage the other axially extending surface of the hub assembly and the electromagnet.

12. 12. The rotary coupling of claim 11, wherein the free end of the shield exerts a spring force against the axially extending surface of the other of the hub assembly and the electromagnet.

13. The rotary coupling of claim 1 , wherein when the electromagnet is energized, magnetic flux travels through the shield from the hub assembly to the electromagnet.

14. 2. The rotary coupling of claim 1, wherein the shield assumes a first state when the electromagnet is not energized, wherein the free end of the shield is axially spaced from the other of the hub assembly and the electromagnet, and wherein the shield deforms to assume a second state when the electromagnet is energized, wherein the shield contacts the other of the hub assembly and the electromagnet.

15. The rotary coupling of claim 1 , wherein the shield is made from a ferromagnetic material.

16. a hub assembly configured to rotate about an axis of rotation, the hub assembly including a rotor hub disposed about the axis of rotation and configured to receive a shaft, and a rotor disk extending radially outward from the rotor hub; an armature disposed on a first axial side of the rotor disk; an electromagnet disposed on a second axial side of the rotor disk opposite the armature and fixed against rotation; a bearing disposed between the rotor hub and the electromagnet, the hub assembly and the electromagnet being separated by an air gap on an outboard side of the bearing; a shield extending across the radial length of the air gap, the shield having a fixed end attached to the electromagnet and a free end opposite the fixed end, the free end configured to engage the hub assembly; and A rotary coupling device comprising:

17. 17. The rotary coupling of claim 16, wherein the free end of the shield extends into the clearance gap and is configured to engage an axially extending surface of the hub assembly.

18. 18. The rotary coupling of claim 17, wherein the free end of the shield exerts a spring force against the axially extending surface of the hub assembly.

19. 17. The rotary coupling of claim 16, wherein when the electromagnet is energized, magnetic flux travels through the shield from the hub assembly to the electromagnet.

20. a hub assembly configured to rotate about an axis of rotation, the hub assembly including a rotor hub disposed about the axis of rotation and configured to receive a shaft, and a rotor disk extending radially outward from the rotor hub; an armature disposed on a first axial side of the rotor disk; an electromagnet disposed on a second axial side of the rotor disk opposite the armature and fixed against rotation; a bearing disposed between the rotor hub and the electromagnet, the hub assembly and the electromagnet being separated by an air gap on an outboard side of the bearing; A rotary coupling comprising: a hub assembly component and one of the electromagnets defining a radially extending shield, the shield being axially aligned with the air gap and extending across the entire radial length thereof, the shield forming a unitary body with the hub assembly component and the one of the electromagnets.

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