A brush assembly to distribute a fluid lubricant about a rotating shaft

Abstract

A system and method for mitigating voltage on a rotating rod exposed to a viscous fluid or immersed in oil-rich environments are disclosed. An example grounding brush assembly comprises a plurality of conductive filaments that extend through a viscous medium surrounding the rotating rod to make electrical contact with the rotating rod when the brush assembly is positioned near the rod.

Description

Technical Field

[0001] This application claims priority to and the benefit of U.S. Provisional Application Serial No. 63 / 046,993, filed on July 1, 2020, entitled “Systems And Methods To Mitigate Electrical Voltage On A Rotating Shaft Immersed In Oil.” The above-listed U.S. applications are incorporated herein by reference in their entirety for all purposes.

[0002] The present disclosure relates to systems and methods for mitigating voltage on a rotating shaft in oil. Prior Art

[0003] In applications using a rotating shaft, such as during motor operation, charge accumulation on the shaft or conductive components of downstream equipment can lead to discharges through bearings or other moving contact interfaces (such as, but not limited to, gear teeth in downstream equipment), resulting in mechanical damage and premature bearing or moving contact interface failure. Various mitigation techniques have been used to overcome this problem, including conductive brushes that contact the rotating shaft with a ground path. However, conventional methods of mitigating voltage in dry environments may not provide adequate protection if the shaft rotates in the presence of fluids, such as oil. Summary of the Invention

[0004] Disclosed are systems and methods for mitigating voltage on a rotating shaft by using a grounding assembly or ring operating in an environment exposed to viscous fluids (e.g., immersion, application, contamination, etc.), substantially as illustrated by and described in conjunction with at least one of the accompanying drawings, as more fully set forth in the claims. Simple diagram description

[0005] FIG. 1 illustrates an example ground brush assembly of a wound rod according to an aspect of the present disclosure.

[0006] FIG. 1A illustrates an alternative example grounding brush assembly around a rod according to aspects of the present disclosure.

[0007] FIG. 1B illustrates an alternative example grounding brush assembly around a rod according to aspects of the present disclosure.

[0008] 2A-2E illustrate example filament patterns in a ground brush assembly according to aspects of the present disclosure.

[0009] 2F and 2G illustrate example filament patterns in a ground brush assembly according to aspects of the present disclosure.

[0010] FIG. 3 is a perspective view of the grounding brush assembly of FIG. 1 according to an aspect of the present disclosure.

[0011] FIG. 4 illustrates another example brush ring assembly defined by an annular body according to aspects of the present disclosure.

[0012] The drawings are not necessarily drawn to scale. Where appropriate, similar or identical reference numbers are used to refer to similar or identical elements. Implementation Method

[0013] Disclosed are systems and methods for mitigating voltage on a rotating rod in an oil environment exposed to viscous fluids using a grounding ring assembly. Specifically, a grounding ring or assembly employs conductive filaments made from fibers that are stiffer than conventional fibers. For example, the fibers may have a thicker diameter, be made from stiffer materials, and / or be prepared using specialized processing (e.g., a composite of multiple smaller fibers bonded together with a polymer matrix material, such as, but not limited to, nylon, polyester, vinyl ester, or epoxy, in a process such as, but not limited to, extrusion or pultrusion). Due to differences in fiber stiffness, strength, and / or surface properties, and the desired properties required for effective rod grounding in environments exposed to viscous fluids, the fibers may be longer than conventional fibers (e.g., extend inward (radially or otherwise oriented) closer to the center of the grounding assembly). For example, the fibers may be configured to contact the rotating rod in a manner different from conventional fibers (e.g., overlap, interference fit, interaction, etc.) (e.g., bending or flexing during rotation to contact the rod and / or align with the rod's surface). Specifically, the bending / flexing of the fibers due to overlap results in sufficient pressure on the fibers to cut through the viscous fluid (and / or withstand pressure from the viscous fluid during rotation) to achieve conductivity (even in the presence of a viscous fluid film between the fiber and the rod, even at high rod speeds, and even at relatively low oil temperatures). In other words, the disclosed stiffer and / or longer fibers contact the rotating rod in a unique manner that breaks through the viscous fluid film but allows each filament to bend without easily breaking or prematurely wearing out. Thus, by penetrating the oil film without excessive contact pressure, the thickness of the oil film layer remaining between the rotating rod and the fiber is reduced to a level below a threshold thickness to allow charge relief or provide direct contact with the rotating rod for charge relief. Consequently, the fibers provide sufficient discharge in environments exposed to viscous fluid (e.g., immersion, application, contamination, etc.) to mitigate bearing and other equipment damage from rod voltage while providing a suitable lifespan. The threshold thickness may depend on the type of viscous fluid, properties of the viscous fluid and / or the film created by the viscous fluid during rotation of the rod, rod surface finish, rod rpm, rod size, and / or other electromechanical factors.

[0014] Induced rod voltage is experienced in various applications, including electric motors and transmissions. Some rod grounding is achieved in a dry environment using relatively small conductive filaments. Due to the low impedance, grounding is possible, even allowing current flow without contacting the rotating rod.

[0015] In contrast, in an oil-rich or oil-immersed environment, conventional conductive filaments may experience forces or currents provided by the oil (e.g., a film, via current flowing through the oil, etc.) and, therefore, may be unable to make contact with the rotating rod. Furthermore, due to the presence of the oil film (e.g., due to increased distance, impedance, etc.), conventional conductive filaments may not be in electrical communication with the rod, and the filaments may be damaged when bent beyond a certain threshold amount. Furthermore, the orientation of conventional conductive filaments may change periodically or randomly during the rotation of the rod due to pressure from the oil. For example, the pressure on the oil may form an oil film between the rotating rod and the fiber, which may then deflect the fiber to a distance that reduces the fiber's effectiveness in discharging the rotating rod.

[0016] The presence of a viscous fluid can coat the fibers with the fluid, causing the fibers and / or fiber bundles to experience saturation, which can affect fiber contact and, therefore, grounding mitigation. Furthermore, once saturated, the viscous fluid must be fully or partially migrated out of the fiber bundle in order for conventional fibers to return to full operating efficiency. Advantageously, the disclosed fibers are less susceptible to saturation (due to physical characteristics such as larger diameter and / or stiffer fibers, and / or the configuration of the fiber bundle and / or around the grounding ring), and, if saturation is achieved, the viscous fluid migrates more readily from the disclosed fibers than from conventional fibers.

[0017] Induced rod voltage is experienced in electric motors, and typically in three-phase motors driven by variable speed drives. Variable speed drives utilize pulse width modulation (PWM) techniques to vary the speed of AC motors. A disadvantage of using AC motors with variable speed drives is that common mode voltage (CMV) is generated by the variable speed drive, which, without adequate voltage mitigation, can increase currents that can damage bearings. While some examples are disclosed with respect to AC and / or rotating rods, the disclosed grounding assembly can be applied to various systems that may experience non-zero voltage differences across bearings. For example, non-zero voltage differences can develop across linear bearings, gearboxes, and / or other electric motors (such as brushless DC motors), which can similarly experience rod voltages based on the switching currents of the motor windings, which can be effectively mitigated by employing the disclosed grounding assembly.

[0018] In the example of a rotating motor shaft, voltage on the shaft causes parasitic or other unwanted currents to flow through the shaft bearings to the motor frame and subsequently to ground. CMV causes the charge to accumulate to a high level over a short period of time. When the charge crosses the discharge threshold of the path of least resistance (sometimes through rolling elements (e.g., balls, needles, fluid, babbitt metal, etc.) in the bearings supporting the shaft), a momentary burst or release of electrical energy travels along the path. For example, in response to a current exceeding a threshold limit (e.g., voltage, current, etc.), electrical or current leakage corrosion can damage contact surfaces. The discharge can cause electric discharge machining (EDM) along the path, which, if the path of least resistance passes through the bearing, can damage the surface of the bearing races and the rolling elements in the bearing. The burst of electrical energy forms melt pits, and particles from the pit formation remain inside the bearing. Both the melt pits and the particulate material in the bearing interfere with the free rotation of the bearing, which can lead to mechanical damage and premature bearing failure. While some disclosed examples are described with reference to a motor shaft, the conductive filaments may also be used to make electrical contact with any application that experiences parasitic voltage buildup within a rotating shaft assembly.

[0019] Various mitigation techniques have been used to attempt to overcome this problem. Conventional techniques include the use of conductive bearing grease, insulating the bearings, and using copper / phosphorus brushes and Faraday shields. Another conventional technique uses spring-loaded solid brushes (e.g., copper, silver-graphite, etc.) to ground the rod. These spring-loaded solid brushes provide a continuous ground current. However, spring-loaded brushes can wear rapidly, requiring frequent, periodic maintenance and replacement, and do not conduct high frequencies well. Due to the alternating friction between the brush and the rod surface, spring-loaded brushes are also prone to vibration. Regardless of the cause, brush vibration can lead to unwanted sparking and / or increased current flowing through the bearing and / or downstream equipment due to reduced surface contact. Furthermore, many of these techniques fail to operate when exposed to large amounts of viscous fluids or oil ingress, often having very low maximum speed limitations or failing to operate at all.

[0020] Other conventional methods include the use of mercury rotary couplings. Besides containing mercury, mercury rotary couplings also corrode contacts in the presence of high currents and / or rapidly changing voltages, causing conductivity to decrease over time and / or releasing mercury in extreme cases. Mercury rotary couplings also require expensive and potentially unreliable sealing mechanisms, have a narrow usable temperature range, and have a low maximum operating speed.

[0021] Conventional methods of mitigating current using dry brushes may not provide adequate protection if a viscous fluid or oil, for example, is used as a lubricant because the high surface area to contact pressure ratio of the dry brush causes the dry brush to ride on an oil boundary layer that is too thick to mitigate the voltage on the rod. Therefore, the disclosed systems and methods of example grounding brush assemblies mitigate current in a rotating rod in the presence of a viscous medium, such as an oil lubricant, a cooling fluid, or a solvent. The grounding brush assembly includes a plurality of conductive filaments that extend through the viscous medium surrounding the rotating rod to make electrical contact with the rotating rod when the brush assembly is positioned proximate the rod.

[0022] In some instances, rotating rods are subject to corrosion and rust and may be treated with oil, lubricants, or other treatments. In some instances, rotating rods may operate in conjunction with other mechanical components, which may subject the rotating rod to various fluids (such as coolants, water, gases, particles, etc.). The presence of these lubricants, coolants, and / or other media may disrupt the operation of conventional rod grounding devices. During the rotation of the rod, this oil may be distributed and / or displaced by contact with the fibers. This oil displacement can reduce the oil volume below a threshold level, rendering it insufficient to provide the desired lubrication and / or corrosion protection benefits. By employing a ring (e.g., grounded or ungrounded) with fibers constructed and / or arranged as disclosed herein, the oil volume can be maintained at a desired level (e.g., above a threshold level) to ensure a lubricating film remains on the rod during operation. Thus, the fiber properties (e.g., length, diameter, hardness, surface area geometry, density, compounding action, placement on the ring, etc.) can be adjusted to tune and / or optimize the oil distribution to achieve a desired result (e.g., a specific threshold level of oil).

[0023] Advantageously, by employing the disclosed grounding ring, a rotating rod can be deployed in environments that would otherwise be impractical due to the possibility that fluid or other media could contact the rod, thereby disrupting the path to ground. The disclosed grounding ring enhances contact with the rotating rod surface contaminated with oil or other media, thereby allowing for an expanded range of use cases.

[0024] In disclosed examples, a grounding brush assembly is used to mitigate current in a rotating rod in the presence of a viscous medium or fluid. The grounding brush assembly includes a plurality of conductive filaments that extend through the viscous medium surrounding the rotating rod to make electrical contact with the rotating rod when the brush assembly is positioned proximate the rod.

[0025] In some examples, the viscous medium is a fluid such as oil. In some examples, the viscous medium is used to distribute around the rod a force applied by contact with at least a portion of the conductive filament during rotation of the rod.

[0026] In some disclosed examples, a grounding brush assembly is used to mitigate current flow in a rotating rod in the presence of oil. The grounding brush assembly includes a first plurality of conductive filaments having a first stiffness and a second plurality of conductive filaments having a second stiffness, wherein one or more of the conductive filaments is configured to extend through the oil to provide electrical continuity with the rotating rod when the brush assembly is positioned proximate the rod.

[0027] In some examples, the first plurality of conductive filaments have a first diameter or a first length, and the second plurality of conductive filaments have a second diameter or a second length. In an example, the brush assembly is for mounting on a rod, and the first or second plurality of conductive filaments are for extending radially inward from an inner diameter of the assembly toward the rod. In an example, the first and second plurality of conductive filaments are uniformly distributed about the inner diameter. In an example, the first plurality of conductive filaments are distributed about the inner diameter in a first distribution pattern, and the second plurality of conductive filaments are distributed about the inner diameter in a first distribution pattern. In an example, the second plurality of conductive filaments are distributed about the inner diameter in a second density.

[0028] In some examples, oil forms a film between the rod and one or more of the first or second pluralities of conductive filaments. In some examples, the oil is displaced about the rod by a force applied during rotation of the rod through contact with at least a portion of the first and second pluralities of conductive filaments. In some examples, during rotation of the rod, contact between the first and second pluralities of conductive filaments and the oil generates a first force against the oil, and contact between the second and second pluralities of conductive filaments and the oil generates a second force against the oil.

[0029] In some examples, one or more of the first plurality of conductive filaments or the second plurality of conductive filaments comprises a composite fiber. In an example, the first or second plurality of conductive filaments comprises at least one of carbon fiber, nickel, stainless steel, a braided fiber, or a conductive plastic.

[0030] In some examples, the first or second plurality of conductive filaments are configured to electrically contact the rod by at least one of direct contact with the rod, via a rod ring, via a rod extension, via a rod tube, or via a gear box.

[0031] In some examples, a ground brush assembly is used to couple to an electrical ground to provide an electrical path between the rod and the electrical ground.

[0032] In some disclosed examples, a brush assembly is used to distribute a fluid lubricant around a rotating rod, wherein the brush assembly includes a plurality of filaments configured to contact the rotating rod when the brush assembly is positioned proximate the rod to generate pressure in the fluid lubricant to distribute the fluid lubricant around the rotating rod in a film having a threshold thickness.

[0033] Referring now more specifically to the drawings and particularly to FIG. 1 , a ground brush assembly 10 is mounted on a rod 16 (e.g., an electric motor 12) in the presence of a viscous medium or fluid 12 (such as oil lubricant, grease, water, particulate contaminants, and / or gas, as a non-limiting list of examples). The example ground brush assembly 10 dissipates electrical charge that may accumulate on the rod 16. The ground brush assembly 10 can be provided in a variety of different sizes for use on rods 16 of varying diameters. The ground brush assembly 10 can be used on a variety of rotating rods, including motors, turbines, conveyors, and other assemblies and configurations where electrical charge may accumulate.

[0034] The brush ring assembly 10 generally surrounds a rod 16 and is operably configured for one or more conductive filaments (e.g., a first plurality of conductive filaments 60 and / or a second plurality of conductive filaments 62) to dissipate, directly or indirectly, via ground, static charge, common mode voltage, and / or other charges that build up on the rod 16 during operation (e.g., of a motor, turbine, gear, etc.).

[0035] In the disclosed example, rod 16 rotates in the presence of oil or other viscous fluid or medium. Due to the presence of oil, conventional conductive filaments may not contact the rod. For example, the oil may form a barrier between the filament and the rod, thereby creating pressure during rotation that forces the filament to deform, breaking contact with the rod. Furthermore, the presence of oil may increase impedance, further limiting electrical continuity between the rod and the filament.

[0036] First plurality of filaments 60 are designed to have a larger diameter than other filament fibers. Additionally or alternatively, the filaments can be longer than other filament fibers and / or have a greater material hardness (e.g., a more rigid material).

[0037] In some examples, a first plurality of conductive filaments 60 are distributed within the channel between outer segment 44 and inner segment 46 to intermix with a second plurality of conductive filaments 62. For example, the second plurality of conductive filaments 62 may have different dimensions than the first plurality of filaments, such as being smaller or larger, shorter or longer, and / or more or less flexible than the first plurality of filaments 60. The space formed between the first and second filaments creates a path for oil flow, thereby preventing the accumulation of an oil film between the rod and the filaments. By preventing oil accumulation, one or more of the first or second filaments can contact the rod to dissipate any charge accumulated thereon. Thus, by penetrating the oil film, the thickness of the oil film layer remaining between the rotating rod and the fiber is reduced to a level below a threshold thickness, allowing for charge relief. Consequently, the fiber provides sufficient discharge in environments exposed to oil or other viscous fluids (e.g., immersion, application, contamination, etc.), while also providing a suitable lifespan. The threshold thickness may depend on the type of oil and the properties of the oil and / or the film created by the oil during the rotation of the rod. In some examples, the first plurality of filaments 60 comprises a different material type than the second plurality of filaments 62. In some examples, the first and second plurality of filaments comprise the same material type. In some examples, one or more bundles of filaments (e.g., the first and / or second plurality of filaments) may comprise multiple material types.

[0038] In some examples, the conductive filaments are epoxy-coated or otherwise treated to increase stiffness and / or displace and / or distribute the viscous fluid as the rod rotates. Furthermore, due to the fibers interacting with different adjacent fibers or fiber bundles through full or partial recombination within the viscous fluid environment, any individual fiber or fiber bundle is less likely to become stuck and / or deform beyond a critical degree. Partial recombination between fibers also acts to increase stiffness to aid penetration of viscous fluid films. In some examples, one or more of the multiple filaments (e.g., within each bundle and / or between bundles) can be bonded to achieve a greater degree of recombination between the fibers (up to and including full recombination), which can further stiffen the bonded fibers.

[0039] In some examples, the first plurality of conductive filaments 60 are capable of deforming in a desired manner (e.g., within a threshold deformation range based on the bend angle, strain, or force experienced by the fiber or a portion thereof). This can be optimized based on a variety of factors, including fiber properties (e.g., diameter, length, material type, material strength, processing, etc.) and / or environmental properties (e.g., temperature, distance between assembly 10 and the surface of rod 16, fluid viscosity, impedance, etc.). This tuning is used to optimize contact pressure to minimize wear on the fiber while providing adequate rod voltage relief. Conductive filaments 60, 62 are configured to bend or flex to follow the surface of the rotating rod regardless of the direction of rotation. As shown in FIG. 1 , rod 16 is rotated clockwise, causing filaments contacting the rod at the top of the image to bend away from the viewer, while filaments contacting the rod at the bottom of the image to bend toward the viewer. In some examples, the rod is configured to rotate in both clockwise and counterclockwise directions, which may or may not cause the filaments to reverse their bend. Thus, the operation and benefits of the disclosed assembly are applicable to rods rotating in a single direction or in counter-rotating directions.

[0040] As shown in FIG. 1 , a mix of different fibers is illustrated such that the first plurality of conductive filaments 60 has a larger length and diameter than the second plurality of conductive filaments 62. In some examples, longer, thicker fibers may be used alone, and one or more of a variety of distribution patterns may be employed to optimize contact with the rod 16 and / or displacement of viscous fluid or oil during rotation of the rod 16. It should be understood that in some embodiments, the number of fibers may be much greater and closer together than shown, with the figures showing greater spacing and a smaller number of fibers for visual clarity. As shown in FIG. 1 , the first plurality of conductive filaments 60 and the second plurality of conductive filaments 62 are configured to contact the surface of the rod 16 during rotation. As disclosed herein, the filaments have a length and strength sufficient to extend through the medium 12, biasing the ends of the filaments against the rod 16 with sufficient force.

[0041] In some examples, the properties of the fibers are optimized based on material stiffness, fiber diameter, and exposed fiber length, as well as the resulting overlap of the fibers with the rod 16 at a suitable contact pressure. In some examples, the diameter of the fibers or fiber bundles is provided as a bundle of 0.0011 inches (e.g., other diameters greater than 0.0003 inches). However, some applications may utilize smaller or larger diameters (e.g., for individual fibers or bundles thereof).

[0042] FIG1A illustrates two alternative examples of grounding brush assemblies 10A and 10B of a winding rod 16 according to aspects of the present disclosure. Similar or identical reference numerals are used in FIG1 to refer to similar or identical elements, with "A" or "B" being used to distinguish between alternative elements.

[0043] In particular, the example grounding brush assembly 10A provides a single lateral segment 44A, exposing on opposite sides the first plurality of conductive filaments 60 and the second plurality of conductive filaments 62. The example grounding brush assembly 10B illustrates the first plurality of conductive filaments 60 and the second plurality of conductive filaments 62 extending from the surface of the inner diameter of the body 40B without any inner or outer segments.

[0044] FIG1B illustrates a side view of an example grounding brush assembly 10 disposed about a rod 16. As shown, a plurality of filaments 60, 62 deform or bend as the ends of the filaments contact the surface 17 of the rod 16. In the example of FIG1B, filaments 60 have a longer length than filaments 62, so that filaments 60 deform by a greater amount than filaments 62.

[0045] As shown in the examples of Figures 2A through 2E , a first plurality of conductive filaments 60 and a second plurality of conductive filaments 62 can be distributed within a channel defined by an inner diameter formed between outer segment 44 and inner segment 46. The resulting separation between the fibers can provide advantages by providing space for viscous fluids in the environment to move away from the fiber-to-rod interface. Although described in some examples as being within the channel, in some examples, filaments 60, 62 are secured to base 48 without outer or inner segments and can be secured to a side surface of the body, extend through base 48, or secured by another suitable technique (as shown in the non-limiting examples of Figures 1A and 4 ). Additionally or alternatively, in some examples, the fibers can be oriented substantially radially inward, can be oriented at one or more angles other than substantially toward the center, can be a mixture of fibers or fiber bundles having two or more orientations, and can be continuous or discontinuous depending on the specific application or desired result. In some examples, the continuous fiber is looped so that both ends of the fiber are fastened to the body, with the middle of the fiber flexing to contact the rod. Continuous fiber can provide a longer wear life than discontinuous fiber, which is fastened to the body at one end and contacts the rod at the opposite end.

[0046] In the example of FIG. 2A , columns of each of the first plurality of conductive filaments 60 and the second plurality of conductive filaments 62 are arranged side by side, spanning the inner diameter of the body 40 . In the example of FIG. 2B , a single column is provided with alternating fibers from the first plurality of conductive filaments 60 and the second plurality of conductive filaments 62 within the channel. In the example of FIG. 2C , a column includes alternating bundles of each of the first plurality of conductive filaments 60 and the second plurality of conductive filaments 62 . In the example of FIG. 2D , the number of conductive fibers in the first plurality of conductive filaments 60 and the second plurality of conductive filaments 62 can vary. As shown, the first plurality of conductive filaments 60 can include larger diameter fibers 60A, which can be arranged in a pattern with the filaments 60. Similarly, the second plurality of conductive filaments 62 can include larger diameter fibers 62A, which can be arranged in a pattern with the filaments 62.

[0047] In the example of FIG. 2E , the conductive fibers of the first plurality of conductive filaments 60 are arranged around the second plurality of conductive filaments 62. In some examples, the first plurality of conductive filaments 60 may be adjacent to and / or arranged in close proximity to the second plurality of conductive filaments 62, which are arranged in the center of the resulting fiber bundle. For example, the second plurality of conductive filaments 62 may be pultruded or otherwise have a greater stiffness than the first plurality of conductive filaments 60. The configuration illustrated in FIG. 2E thus provides increased strength to the first plurality of conductive filaments 62 during rotation of the rod 16. In some examples, the first plurality of conductive filaments 60 have a larger diameter than the second plurality of conductive filaments 62 but benefit from the stiffness provided by the partial recombination between the fibers, thereby imparting the necessary pressure to extend through the viscous fluid film and make electrical contact with the rod 16.

[0048] Although generally illustrated as being evenly spaced, the distance between individual fibers and / or fiber bundles and the inner walls of the outer and inner segments 44, 46 (and / or the sides of the base 48 in the absence of an outer or inner segment) and the individual fibers and / or fiber bundles may be adjusted.

[0049] Furthermore, while the conductive filaments are illustrated as having a generally circular shape, other geometric shapes are contemplated, including substantially flat, rectangular, triangular, and elliptical, as a non-limiting list of examples. The shape and / or size may be selected to initiate a specific flow pattern of the viscous fluid (e.g., between individual fibers and / or fiber bundles) and to deform in a specific manner in the presence of the viscous fluid oil to encourage contact with the rod during rotation.

[0050] In some examples shown in Figures 2F and 2G, the brush ring assembly can have a single type of filament in one or more configurations (e.g., as shown in Figures 2A through 2E). For example, Figure 2F illustrates fibers (e.g., filament bundles) 60A having a greater length than fibers 60B, with fibers 60A and 60B containing a common material. In the example of Figure 2G, fibers 62A have a greater length than fibers 62B, with fibers 62A and 62B containing a common material. Other variations in addition to or in lieu of length can include filament diameter, bundle configuration, and distribution around annular body 40, as a list of non-limiting examples. Furthermore, while illustrated as having filaments having multiple lengths, in some examples, some or all filaments (e.g., filament 60) have a single length.

[0051] As shown in FIG. 3 , the example brush ring assembly 10 is defined by an annular body 40, wherein a plurality of conductive filaments 60, 62 comprise the brush assembly 10 disposed within the annular body 40. The annular body 40 includes an outer section 44, an inner section 46, and a base 48. The outer section 44, the inner section 46, and the base 48 together form an annular channel in which the brush assembly 10 is disposed. The example annular body 40 is made of a conductive material, such as a metal, including but not limited to aluminum, stainless steel, bronze, and / or copper, and / or a conductive plastic.

[0052] The example brush assembly 10 includes a plurality of individual fibrous conductive filaments (e.g., the first plurality of conductive filaments 60 and / or the second plurality of conductive filaments 62) that can be arranged individually in a substantially continuous ring and / or in a plurality of filament bundles arranged circumferentially around the rod 16. In some examples, each filament is a thin, hair-like filament made of carbon fiber, nickel, stainless steel, conductive plastic, or any other conductive fiber type, including blends and composites thereof, such as nickel-coated carbon fiber or copper-coated steel fiber.

[0053] In some of these examples, one or more of the first plurality of conductive filaments or the second plurality of conductive filaments 62 can have a diameter of less than about 150 microns. The conductive filaments can have a diameter in the range of about 5 microns to about 100 microns. Alternatively, the conductive filaments 60, 62 can be larger fibers of conductive material that maintain contact with the rod 16. In some examples, the conductive filaments are integral with the annular body 40 (such as by additive manufacturing).

[0054] The example conductive filament is secured within the body 40 by one or more techniques, such as an anchor structure that is electrically conductive and can be in the form of a clamping structure, such as a plate, between which the conductive filament is retained. Alternatively, the conductive filament can be secured by an electrically conductive filler material, such as a conductive plastic, a conductive adhesive, a non-conductive discontinuous adhesive, or the like, thereby anchoring the conductive filament within the body 40. A portion of the distal end of the conductive filament can extend inward (e.g., oriented substantially, but not necessarily, directly radially inward relative to the grounding brush assembly 10) toward the rod 16 through the outer segment 44 and the inner segment 46. The thin, lightweight conductive filament is in physical contact with the rod 16 for direct charge transfer from the rod 16 without significant wear during operation.

[0055] In some examples, the conductive filaments 60, 62 completely surround the rod 16 and conduct the rod voltage to ground. In some examples, the conductive filaments 60, 62 gradually wear to match the rod 16. When the conductive filaments 60, 62 have worn to match the rod 16, the wear rate of the conductive filaments 60, 62 is significantly reduced, and the conductive filaments maintain electrical contact with the motor rod 16.

[0056] The transfer of charge from the rod 16 to the conductive filaments 60, 62 occurs directly by bringing the conductive filaments 60, 62 into touching contact with the rod 16. Charge can be transferred from the conductive filaments 60, 62 through the body 40 and a ground connection (e.g., via a path to chassis ground, ground, a reference voltage, etc.). Thus, before arcing can occur, the charge that builds up on the rod 16 is dissipated to ground through the grounding brush assembly 10. As used herein, the term "ground" refers to any circuit path that allows a grounding device to reduce the voltage difference between the rod 16 and one or more of the bearings and / or downstream equipment (such as gears, bearings, or the like).

[0057] The example conductive filaments 60, 62 protect motor bearings electrically connected to the shaft 16 from electrical damage throughout the L-10 life of these bearings. For example, the conductive filaments may be sufficient to protect any bearing electrically connected to the shaft 16 from failure due to overcurrent corrosion (as defined in ISO 15243:2017, Section 5.4.2) and / or current leakage corrosion (as defined in ISO 15243:2017, Section 5.4.3) for at least the L-10 life of the bearing. In other words, the example conductive filaments 60, 62 can substantially eliminate excessive current and / or current leakage corrosion as causes of bearing failure. The L-10 life of a bearing refers to the number of service hours that a bearing of that type will survive 90% of the time and varies depending on the application.

[0058] Although the disclosed examples are described above with reference to motor shafts, conductive filaments may also be used to make electrical contacts within slip rings for current transfer.

[0059] FIG4 illustrates another example brush ring assembly 70 defined by an annular body 72, wherein a plurality of conductive filaments 70 are disposed within the annular body 40. Although illustrated with a substantially single fiber, some example brush ring assemblies 70 may include multiple conductive filaments and / or filament types (e.g., conductive filaments 60, 62) in addition to or as an alternative to the conductive filament 70. In some examples, the annular body 72 includes an outer segment, an inner segment, and a base similar to assembly 10, which form an annular channel in which the conductive filaments form a brush.

[0060] As shown, the conductive filaments of the example brush assembly 70 include a plurality of filament bundles that can be individually arranged in a substantially continuous annular ring and / or arranged circumferentially around a rod. In some examples, each filament is oriented toward the interior of the body 72 but at an angle offset from the radius. The angled fibers 74 can overlap the rod at the flatter portion of the distal end of the fibers, so that each fiber 74 experiences less force and, therefore, less bending (e.g., compared to radially oriented fibers). Consequently, the conductive fibers 74 can experience less wear by being tuned to the correct contact pressure through geometric stiffness, without requiring precisely different fiber bundle diameters for different applications.

[0061] The example conductive filaments are secured within the body 40 by one or more techniques, such as those described with respect to the assembly 10. Advantageously, the angle at which the fibers 74 contact the rod does not substantially change if the rod is rotated in a reverse direction.

[0062] As used herein, "and / or" means any one or more of the items in the list connected by "and / or." As an example, "x and / or y" means any element in the three-element set {(x), (y), (x, y)}. In other words, "x and / or y" means "one or both of x and y." As another example, "x, y, and / or z" means any element in the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, "x, y, and / or z" means "one or more of x, y, and z." As used herein, the term "exemplary" means serving as a non-limiting example, instance, or illustration. As used herein, the terms "e.g.," and "for example," provide a list of one or more non-limiting examples, instances, or illustrations.

[0063] Although the present method and / or system has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present disclosure. Furthermore, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the scope of the present disclosure. For example, the systems, blocks, and / or other elements of the disclosed examples may be combined, divided, reconfigured, and / or otherwise modified. Therefore, the present method and / or system is not limited to the particular embodiments disclosed. On the contrary, the present method and / or system is intended to include all embodiments coming within the scope of the appended claims, both literally and under the doctrine of equivalents.

[0064] 10, 10A, 10B: Grounding brush assembly 12: Viscous medium or fluid 16: Rod 17: Surface 40, 40B: Main body 44: Outer section 44A: Horizontal section 46: Inner section 48: Base 60: first plurality of conductive filaments 60A, 60B, 62A, 62B: Fiber 62: Second plurality of conductive filaments 70: Brush ring assembly 72: Ring body 74: Fiber

[0065] Domestic storage information (please note the order of storage institution, date, and number) none

[0066] Overseas deposit information (please note the order of deposit country, institution, date, and number) none

Claims

1. A brush assembly for distributing a fluid lubricant about a rotating rod, wherein the brush assembly comprises: A body having an inner channel; a first plurality of filaments having a first length and distributed at a first radial position within the inner channel; and a second plurality of filaments having a second length and distributed at a second radial position within the inner channel; wherein the first and second plurality of filaments are configured to extend radially inward toward the rotating rod in a common direction, and when the brush assembly is disposed near the rotating rod, the first and second plurality of filaments substantially contact the rotating rod and maintain electrical continuity with the rotating rod to generate a pressure in the fluid lubricant to distribute the fluid lubricant around the rotating rod in a film having a critical thickness.

2. The brush assembly as claimed in claim 1, wherein the inner channel is defined by an inner diameter, wherein the first and second plurality of filaments extend from the inner diameter to a surface of the rotating rod, the first plurality of filaments being distributed in the inner channel in a first pattern, and the second plurality of filaments being distributed in the inner channel in a second pattern.

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