Bearings and bearing liners

Abstract

Products and methods for manufacturing bearings with bearing liners, as well as the bearing liners themselves. The bearing liners within the bearings include a fabric having an adhesive side polymeric resin composition applied to one side and a sliding side polymeric resin composition disposed on a second side containing a dispersed lubricant. The liner preparation also provides the ability for the liner to conform to a selected bearing surface.

Description

[Technical Field]

[0001] Field The present invention relates to products and methods for manufacturing bearings having bearing liners, as well as the bearing liners themselves. The bearing liners within the bearings include a fabric having an adhesive side polymeric resin composition applied to one side and a sliding side polymeric resin composition disposed on a second side containing a dispersed lubricant. The liner preparation also provides the ability for the liner to conform to a selected bearing surface. [Background technology]

[0002] background The prior art contains various disclosures of bearing liners aimed at reducing friction and liner wear over an extended bearing life. Specifically, the objective is to reduce the level of liner wear and running torque that can be observed over the bearing life, i.e., at relatively high vibration cycles. Furthermore, it has been aimed to reduce the initial running torque (i.e., friction) at the zero-cycle wear point at the start of rotation and shorten the relatively long break-in period characterized by relatively high initial running torque. Bearing wear tests include SAE Standard AS81934 Wear Test and AS81934 Running Torque Evaluation. Summary of the Invention [Means for solving the problem]

[0003] overview A bearing comprising a liner including a woven or nonwoven fabric having a first adhesive surface containing a first adhesive side resin composition including a polymeric resin, and a second sliding surface having a second sliding side resin composition including a polymeric resin and one or more dispersed lubricants.

[0004] A bearing liner comprising a woven or nonwoven fabric having a first adhesive surface containing a first adhesive-side resin composition comprising a partially polymerized resin, and a second sliding surface having a second sliding-side resin composition comprising a partially polymerized resin and one or more dispersed lubricants. The liner, with the partially cured and polymerized resin on both the adhesive surface and the sliding surface, can then be engaged and conformed to the bearing surface and fully polymerized.

[0005] A method for providing a bearing liner or bearing includes providing a woven or nonwoven fabric having a first surface and a second surface, coating the first adhesive surface of the fabric with a first adhesive side resin composition containing a polymerizable resin, and partially polymerizing the coating. This is followed by coating the second sliding surface of the fabric with a second sliding side resin composition containing a polymerizable resin and one or more lubricants, and partially polymerizing the coating. The order of coating and partial polymerization can be reversed. The liner thus produced can be engaged with a bearing surface requiring a bearing liner and fully polymerized.

[0006] A method for providing a bearing liner or bearing includes providing a woven or nonwoven fabric having a first surface and a second surface, coating the first surface of the fabric with a first adhesive-side resin composition containing a UV-polymerizable resin, and partially polymerizing the first surface. This is followed by coating the second surface of the fabric with a second sliding-side resin composition containing a UV-polymerizable resin and one or more lubricants, and partially polymerizing the second surface. The order of coating and partial polymerization can be reversed. The liner thus produced can be engaged with a bearing surface requiring a bearing liner and fully polymerized. [Brief explanation of the drawings]

[0007] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1] FIG. 1 is a diagram of a plain weave bearing liner fabric that provides a first adhesive surface for engaging a bearing and a second sliding surface. [Figure 2]1 provides another view of a bearing liner fabric that provides a first adhesive surface for engaging a bearing and a second sliding surface. [Figure 3] FIG. 1 is a cross-sectional view of an example fabric sliding bearing liner. [Figure 4] Another cross-sectional view of a preferred embodiment of a fabric sliding bearing liner is shown, where the volume of the 1BSRC (22) is relatively large compared to the 2SSRC (24). [Figure 5] Another cross-sectional view of a preferred embodiment of a fabric sliding bearing liner is shown, where the volume of the 2SSRC (24) is relatively large compared to the 1BSRC (22). [Figure 6] FIG. 1 is another cross-sectional view of a preferred embodiment of a fabric sliding bearing liner, in which the 2SSRC (24) is elevated a certain height above the fabric warp threads 16, as indicated at 26. [Figure 7] FIG. 2 is another cross-sectional view of a preferred embodiment of a fabric sliding bearing liner, in which weft yarns 16 protrude from 1BSRC (22) as indicated by arrow 28. [Figure 8] FIG. 1 is a diagram of a test fabric specimen configured for application of 1BSRC polymerizable resin. [Figure 9] One non-limiting example is shown in which parallel beads of 1BSCR polymerizable resin are applied to a test piece of fabric. [Figure 10] 1 shows one non-limiting example of the use of a clipboard fabric holder to hold a fabric liner and pass it through a UV conveyor to facilitate partial polymerization of the applied 1BSRC or 2SSRC. [Figure 11] 1 shows the results of high pressure AS81934 military specification sleeve bearing wear testing comparing a commercial bearing (43) AHJ08C012(L1) fitted with an X-1820 liner containing only PTFE fiber lubricant to the same bearing (45) AHJ08C012(L1) fitted with an X-1820 liner containing PTFE fiber lubricant and also containing vacuum impregnated perfluoropolyether oil Krytox GPL105. [Figure 12]1 shows the results of AS81934 bearing wear tests conducted under a nominal liner stress of 37,500 psi, comparing the wear of a commercial bushing lined with the X-1820 liner described above (line 42) to a bushing lined with a fabric liner described herein containing 1 BSRC as shown in Table 1 and 2 SSRC as shown in Table 2 (44). [Figure 13A] Figure 12 shows a graph of the rotational torque measured during the AS81934 bushing wear test, showing the rotational torque over the first 25,000 cycles. [Figure 13B] FIG. 12 shows a graph of the rotational torque measured during the AS81934 bushing wear test, showing the rotational torque over the entire 100,000 cycle test. [Figure 14] A bearing is shown having a first member 50 having a surface 51 and a second member 52 having a surface 53 configured for sliding contact. A fabric sliding bearing liner 54 as described herein is disposed between the first member 50 and the second member 52. [Figure 15] 1 provides a cross-sectional view of a general type of bearing of the present invention, specifically a rolling bearing including a fabric sliding liner bearing 54 as described herein. DETAILED DESCRIPTION OF THE INVENTION

[0008] Detailed Description The present invention relates to products and methods for bearings having bearing liners, as well as the bearing liners themselves. The bearing liners include a fabric having an adhesive-side polymerizable resin composition applied to one surface and the interior thereof and a sliding-side polymerizable resin composition disposed on a second surface and the interior thereof. Preferably, the sliding-side polymerizable resin composition includes at least one additive, such as a lubricant, that is not included in the adhesive-side composition. The lubricant is preferably dispersed in the sliding-side polymerizable resin composition, most preferably uniformly dispersed. References to the feature that the lubricant is dispersed in the sliding-side resin composition refer to the feature that the lubricant is present in the sliding-side polymerizable resin composition. Thus, when the sliding-side composition is subjected to surface wear, the dispersed lubricant can remain available on the surface of the sliding-side resin composition.

[0009] The fabric itself is preferably a nonwoven or woven fabric, and is preferably permeable, which may initially allow the adhesive side polymerizable resin composition and / or the sliding side polymerizable resin composition to penetrate into portions of the fabric and initially undergo partial polymerization.

[0010] 1 is a diagram of one preferred permeable plain weave fabric 10, which here provides a first adhesive surface 12 and a second sliding surface 14. That is, the first adhesive surface 12 is configured to receive an adhesive side polymerizable resin composition, and the second sliding surface is configured to receive a sliding side polymerizable composition, preferably including a lubricant, as further described herein.

[0011] The fabric thus selected has an initial and measurable air permeability that is a property of the entire fabric. Preferred levels of initial airflow permeability are discussed further herein.

[0012] 2 provides a diagram of another preferred fabric 20, again including a first adhesive surface 12 and a second sliding surface 14, which will ultimately be engaged with a bearing and configured as a bearing liner. What is shown in FIG. 2 is sometimes also identified as a satin weave. In this situation, the adhesive surface 12 and the sliding surface 14 of the fabric itself may provide different surface characteristics for the introduction of adhesive-side or sliding-side polymerizable resins.

[0013] Fabrics (woven or nonwoven) for bearing liners herein are preferably composed of fibers derived from fiber-forming polymers, which may include aromatic polyamides (e.g., Nomex® and / or Kevlar®), polyimides, nylons or aliphatic polyamides, polyesters (e.g., PET), polyacrylates, polyethylene, glass, carbon fibers, polyamideimides, polyetherketones, polyphenylene sulfides, polypropylene, polyphenylene sulfide, and / or polybenzimidazole. One particularly preferred fabric is HT-527, available from Stern and Stern Industries, which is composed of polyaramid and polytetrafluoroethylene fibers.

[0014] Fabrics for bearing liners herein preferably have a thickness ranging from 0.005 inches to 0.030 inches, inclusive of all individual values ​​and increments therein, at a basis weight of 5.0 grams per square foot to 70 grams per square foot, inclusive of all individual values ​​and increments therein. Fabrics for bearing liners also preferably have a permeability, as measured by air flow, ranging from 1.0 cubic feet per meter (cfm) to 1500 CFM, inclusive of all individual values ​​and increments therein, as measured in accordance with ASTM D737(2018) (Standard Test Methods for Air Permeability of Textile Fabrics).

[0015] 3 is a cross-sectional view of an example of a fabric sliding bearing liner, shown here in end view with weft yarns 18 and warp yarns 16. First adhesive surface 12 contains a first adhesive side resin composition (1BSRC) containing a polymerizable resin, designated 22. More preferably, the 1BSRC can penetrate the adhesive surface of the fabric (i.e., the surface of the liner that will ultimately adhere to the selected bearing surface), and even more preferably, encapsulates the adhesive surface of the fabric.

[0016] The second sliding surface 14, which contains a second sliding side composition (2SSRC) containing a polymerizable resin, is designated 24. The 2SSRC preferably penetrates the second sliding surface of the fabric (i.e., the surface of the liner that frictionally engages the counter surface), and even more preferably encapsulates the second sliding surface of the fabric.

[0017] In the non-limiting illustration provided in Figure 3, the volumes of the 1BSRC and 2SSRC appear to be approximately equal. In practice, it may be preferable to make the relative volumes of either the 1BSRC or the 2SSRC larger or smaller, or it may be desirable to make the volumes of both the 1BSRC and the 2SSRC larger or smaller simultaneously. Thus, it is also preferable that the fibers 16 and / or 18 may protrude above the surface of either the 1BSRC or the 2SSRC or both the 1BSRC and the 2SSRC. Conversely, it is preferable that the textile fibers 16 and / or 18 may be positioned below the surface of either the 1BSRC or the 2SSRC or below the surfaces of both the 1BSRC and the 2SSRC.

[0018] It is therefore noted here that the fabrics herein (e.g., 10 or 20 in Figures 1 and 2) may optionally be treated prior to coating to improve adhesion of the 1BSRC and 2SSRC. Such treatment may preferably include chemical treatment, while other fabric treatment procedures may include applying ionizing energy or plasma treatment to the fabric fibers 16 and / or 18 immediately prior to coating with the 1BSRC and 2SSRC.

[0019] Additionally, fabrics for bearing liners are preferably selected according to measurements of initial airflow through the fabric. Preferably, airflow through fabrics herein is measured according to ASTM D737(2018). Accordingly, it is preferred herein that the airflow through the fabric be selected to be 100 cfm or less or in the range of 1 cfm to 100 cfm, including all values ​​and increments therein. Thus, the airflow through the fabric can be in the range of 1 cfm to 90 cfm, 1 cfm to 80 cfm, 1 cfm to 70 cfm, 1 cfm to 60 cfm, 1 cfm to 50 cfm, 1 cfm to 40 cfm, 1 cfm to 30 cfm, 1 cfm to 20 cfm, or 1 cfm to 10 cfm. Next, in situations where either the 1BSRC or the 2SSRC is selected to contain an additive such as a fibrous filler, when such a fiber-containing resin composition is applied to the surface of the fabric 10 or 20 (FIGS. 1-2), selecting an airflow in the relatively low portion of the above range (e.g., 1 cfm to 50 cfm, or more preferably 1 cfm to 25 cfm) can relatively prevent the fibrous filler from passing through the entire thickness of the fabric and depositing on the opposite surface. Therefore, such fibrous filler can preferably be deposited and accumulated at a relatively high concentration on or near the surface of the fabric into which it is introduced, without passing through the entire thickness of the fabric and reaching the opposite surface. In other words, the fibrous filler can be present only in the 1BSRC and not in the 2SSRC.

[0020] Thus, herein, by selecting a relatively low air flow over the fabric (e.g., 1 cfm to 50 cfm), for example, fiberglass-type fibers can be preferably and selectively positioned at or near the surface of the fabric liner in the 1BSRC, or by selecting a relatively high air flow (e.g., greater than 50 cfm to 100 cfm), such fillers and the fillers can be more evenly distributed on the side of the fabric liner infiltrated with the 1BSRC, improving the adhesion and strength of the fabric liner when adhered to a given bearing surface, while not compromising the frictional properties of the 2SSRC.

[0021] Furthermore, one could selectively include fluorocarbon fibers (e.g., PTFE fibers) in the 2SSRC, then use a fabric with relatively low airflow, with such fluorocarbon fibers preferably concentrated at or near the surface of the sliding side of the fabric. Or, again, select a fabric with relatively high airflow, with such PTFE fillers more uniformly distributed on the liner side containing the 2SSRC. Such fluorocarbon fibers could serve to reduce friction. As used herein, references to preferably and selectively disposing fibers at or near the surface are considered to be disposing at the surface of the 2SSRC or to a thickness of 0.010 inches. Furthermore, it is therefore possible herein to selectively dispose fluorocarbon fibers only in the 2SSRC and not in the 1BSRC.

[0022] Furthermore, it can now be generally appreciated that the present invention provides the ability to include in a 2SSRC additive that selectively penetrates the fabric liner and promotes improved wear resistance and can maintain the relatively low friction of the 2SSRC when employed in a given bearing application. Similarly, a 1BSRC can include additives, such as glass fiber, that tend to improve the adhesive properties and strength of the 1BSRC when it adheres to a given surface and subsequently functions as a bearing liner.

[0023] Thus, the fabric liner herein, including warp yarns 16 and weft yarns 18, can be manufactured with 1BSRC and 2SSRC (see again FIG. 3, items 22 and 24), which can be made to have different compositional properties due to the presence of different selected additives. When used as a bearing liner, this fabric liner uniquely achieves different fabric surface properties, such as improved abrasion resistance, strength, and stiffness, on each side of a single fabric liner. Reference to different compositional properties refers to the presence or absence of at least one component between 1BSRC and 2SSRC.

[0024] The first adhesive side resin composition (1BSRC) and the second sliding side resin composition (2SSRC) herein preferably contain a polymerizable resin. Preferably, the 1BSRC and the 2SSRC are first partially cured or partially polymerized, which can be achieved by exposure to heat and / or UV light. The partial polymerization results in a single liner that maintains sufficient flexibility and conformability to be applied to a given surface requiring a bearing liner. Preferably, the partial polymerization of the polymerizable resin in the 1BSRC and the 2SSRC is such that the fabric liner maintains sufficient flexibility to fit and position within the inner diameter of a bore having, for example, a 0.375-inch inner diameter. That is, the fabric liner fits and is positioned within the inner diameter of such a bore, and the 1BSRC contacts and engages (adheres or adheres) with the inner diameter surface of the bore.

[0025] Partial polymerization, as used herein, is preferably characterized by conversion (polymerization) of the monomer resin initially present in the 1BSRC and / or 2SSRC to a preferred level of at least 50.0%, more preferably in the range of 50.0% to 99.0%, including all individual values ​​and increments therein. One possible technique for distinguishing partial polymerization or curing from full polymerization or curing is dynamic mechanical analysis (DMA), which can measure the liner's elastic modulus. More specifically, the elastic modulus increases upon full polymerization or curing (e.g., in the case of thermosetting resins, where the highest degree of crosslinking is achieved). Thus, the DMA of a fully polymerized or fully cured sample can be readily established and compared with the DMA of a given sample to identify whether the sample is partially polymerized or partially cured, or fully polymerized or fully cured. Furthermore, as previously mentioned, partial polymerization or curing is also confirmed by the characteristic that the liner maintains sufficient flexibility to fit and position within the inner diameter of, for example, a 0.375-inch bore.

[0026] Partial polymerization may be otherwise characterized by the presence of a relatively small amount of migratable liquid in the liner, which will be absorbed after 24 hours of contact with 4.0 square inches of Kraft paper. The Kraft paper is Delta Paper Corp 3050KP. Preferably, the amount of such migratable resin in the 1BSRC and / or 2SSRC after partial polymerization ranges up to 20.0 weight percent of the polymerizable resin originally present.

[0027] The polymerizable resin for the 1BSRC and / or 2SSRC is preferably selected from one or more of a monomeric resin, an oligomeric resin, a resin solution, a resin suspension, or a resin dispersion, and includes a polymerizable resin that polymerizes into a homopolymer or copolymer, ultimately providing a thermoplastic and / or thermosetting (crosslinked) material. The polymerizable resin for the 1BSRC and / or 2SSRC preferably forms one or more of the following polymers: poly(acrylate), phenolic resin, aromatic polyamide, epoxy resin, polyimide, poly(amideimide), polyetherketone, polyetheretherketone, or polyester. Preferably, the polymerizable resin is capable of curing (polymerizing) upon exposure to UV light, which can occur in the presence of a UV polymerization initiator. Polymerization can also be initiated using a combination of a thermal polymerization initiator (e.g., a free-radical initiator) and the introduction of heat.

[0028] One particularly preferred monomer composition for polymerization of 1BSRC and / or 2SSRC is a mixture of tris(2-hydroxyethyl)isocyanurate triacrylate monomer (30% by weight) and trimethylolpropane triacrylate (70% by weight). Such a monomer composition is preferably polymerized by UV light. A preferred initiator for UV polymerization is a liquid photoinitiator manufactured by Sartomer Corporation called Speed ​​Cure 4265, which is identified as a liquid formulation exhibiting absorbance maxima at 240, 273, and 380 nm. Preferably, the UV polymerization initiator in 1BSRC and / or 2SSRC is present at a level of 0.05 to 5.0 parts by weight per 100 parts by weight of the polymer resin in the 1BSRC or 2SSRC undergoing polymerization.

[0029] More broadly related to the present invention, preferred UV light sources for initially promoting partial cure (partial polymerization) and / or full cure of the polymer resin in the 1BSRC and / or 2SSRC include mercury vapor, LEDs, excimer lamps, and electrodeless UV. Preferred power levels for promoting such partial polymerization can range from 60 W / cm to 300 W / cm. A particularly preferred microwave-driven UV bulb is offered by Heraeus, Inc., under the model number F300S. This UV bulb has most of its output concentrated at wavelengths around 410-420 nm. The UV exposure time for promoting partial polymerization in the 1BSRC and / or 2SSRC is preferably in the range of about 1-3 seconds (the length in feet of the microwave-driven UV lamp in the machine direction, as measured with a tungsten screen, divided by the speed of the conveyor belt in feet per second). The energy transmitted through the UV conveyor system, as measured with an EIT Uvicure Power Pack II, is preferably in the range of approximately 0.1-0.5 J / cm. 2 (UVA), 0.05-0.5J / cm 2 (UVB), 0.010-0.100J / cm 2 (UVC) and 0.5 to 5.0 J / cm 2 (UVV). The preferred level of UV initiator to promote such initial partial polymerization in a 1BSRC or 2SSRC is 0.05 to 5.0 parts by weight per 100 parts by weight of the resin to be partially polymerized.

[0030] It can therefore be understood that the 1BSRC or 2SSRC can contain the same or different polymerizable resins to undergo polymerization. Preferably, it is useful to select the same polymerizable resin for the 1BSRC and 2SSRC, as this tends to maximize the relatively improved adhesion and cohesion at the interface "I" between the 1BSRC and 2SSRC (see Figure 3).

[0031] Preferably, the 1BSRC and the 2SSRC differ in the composition of additives (components other than the polymerizable resin). For example, the 2SSRC preferably includes one or more lubricant additives not present in the 1BSRC, which lubricant is designed to reduce the friction characteristics of the 2SSRC. Preferably, the 1BSRC includes a glass fiber filler to enhance adhesive strength to a given bearing surface, which glass fiber filler is not present in the 2SSRC.

[0032] The lubricant additive may preferably be selected from fibrous and / or particulate lubricants to reduce friction between the 2SSRC and the surfaces it may frictionally engage when positioned as a liner in a bearing application. Accordingly, preferred lubricants include one or more of the following: fibrous or particulate polytetrafluoroethylene, perfluoropolyether, graphite, polyaramid fiber, molybdenum disulfide, hexagonal boron nitride, and graphene. Preferred lubricant additives may also include lubricating oils. Preferably, the level of such lubricant in the 2SSRC is 1.0 wt. % to 60.0 wt. % (including all individual values ​​and ranges therein), more preferably 25.0 wt. % to 55.0 wt. % (including all individual values ​​and ranges therein).

[0033] A particularly preferred lubricant in a 2SSRC is a combination of a polytetrafluoroethylene (PTFE) powder-based lubricant, available from Chemours under the name ZONYL™, and a perfluoropolyether (PFPE) oil, available from Chemours under the name Krytox GPL105. Perfluoropolyether refers to polymer chains containing perfluoroalkyl groups linked by ether linkages. ZONYL™ is identified as a solid particulate PTFE lubricant containing an average particle size (by volume) ranging from 2 μm to 20 μm. As noted above, the combination of the PTFE particle-based lubricant and the PFPE lubricant may preferably be present in the 2SSRC at a level of 1.0 wt.% to 60.0 wt.%. However, in one particularly preferred lubricant combination, the PTFE particulates are present in the 2SSRC at a level of 15.0 wt.% to 22.0 wt.% and the PFPE lubricant is preferably present in the 2SSRC at a level of 25.0 wt.% to 33.0 wt.%.

[0034] As previously mentioned for the 1BSRC, the composition includes a polymerizable resin, preferably with additives to optimize strength and adhesive properties. Accordingly, the polymerizable resin preferably includes one or more of the following: UV initiators, thermal initiators, fibers (short or milled) such as glass and / or carbon fibers, and particulate additives such as clay, titanium dioxide, inorganic silicates, colorants, and stabilizers such as antioxidants and thermal stabilizers. When fibers are present, they are preferably present in the 1BSRC in a range of 2.0% to 40.0% by weight (including all individual values ​​and increments therein). Such fibers preferably have diameters ranging from 10.0 microns to 25.0 microns and lengths ranging from 175 microns to 250 microns. More preferably, milled glass fibers having diameters ranging from 15.0 microns to 17.0 microns and lengths ranging from 200 microns to 225 microns can be used.

[0035] One particularly preferred fiber is available from Fibertec under the designation Microglass 9132, which is identified as a microglass milled fiber (E-glass filament) having a fiber diameter of 16.0 microns, a fiber length of 220 microns, a bulk density of 0.78 g / cc ± 0.08 g / cc, and is silane treated to improve adhesion to the polymerized resin in the adhesive side resin.

[0036] Referring now to FIG. 4, another cross-sectional view of a preferred embodiment of a fabric sliding bearing liner is shown, where the volume of the 1BSRC (22) is relatively larger compared to the 2SSRC (24).

[0037] Referring now to FIG. 5, another cross-sectional view of a preferred embodiment of a fabric sliding bearing liner is shown, where the volume of the 2SSRC (24) is relatively larger compared to the 1BSRC (22).

[0038] FIG. 6 is another cross-sectional view of a preferred example of a fabric sliding bearing liner, in which the 2SSRC (24) is elevated a fixed distance above the warp yarns 16 of the fabric, as indicated at 26. Such elevation of the 2SSRC (24) above the warp yarns 16 may preferably range from 0.0005 to 0.005 inches, including all individual values ​​and increments therein. It may therefore be understood that the 1BSRC (22) may similarly be elevated above the warp yarns 16 in the range from 0.0005 to 0.005 inches, including all individual values ​​and increments therein. Alternatively, the 1BSRC (22) and / or the 2SSRC (24) may each be lowered a fixed distance below the warp yarns 16. Such distance may preferably range from 0.0005 to 0.005 inches.

[0039] 7 is another cross-sectional view of a preferred example of a fabric sliding bearing liner, in which warp yarns 16 protrude from the 1 BSRC (22) as indicated by arrow 28. Such protrusion distance may preferably range from 0.0005 inches to 0.005 inches. It can be readily appreciated that warp yarns 16 may also be configured to protrude a distance above the 2 SSRC (24), which protrusion distance may also preferably be from 0.0005 inches to 0.005 inches.

[0040] Thus, it may be understood herein that the outer surface of a fabric liner (referring to the surface of the fibers used to form the fabric liner) may be packed flush, i.e., at the same height, with the 1 BSRC (22) and 2 SSRC (24), as shown in Figure 3, or may be underpacked (e.g., fibers 16 protruding above the 1 BSRC (22)), as shown in Figure 7, or overpacked (e.g., fibers 16 enclosed within and below the surface of the 2 SSRC (24)), as shown in Figure 6. Furthermore, the relative volumes of the 1 BSRC (22) and 2 SSRC (24) may be the same (Figure 3) or different (Figure 4).

[0041] The fabric sliding bearing liners described herein are applied to a bearing surface. With reference to Figure 14, references herein to a bearing refer to any components configured for sliding contact, including a first member 50 having a surface 51 and a second member 52 having a surface 53. A fabric sliding bearing liner 54 described herein is disposed between the first member 50 and the second member 52. The first adhesive surface of the bearing liner 54, again designated 12, contains a first adhesive side resin composition (1BSRC), and the second sliding surface 14 contains a second sliding side resin composition (2SSRC).

[0042] Figure 15 shows, in cross section, a diagram of one common type of bearing of the present invention, specifically a rotary bearing including a fabric sliding liner bearing 54 as described herein. The balls 58 of the bearing have convex outer surfaces that are in sliding contact with the sliding surface 14 of the liner 54, which contains the second sliding side resin composition (2SSRC). What is typically described as a race component, designated 60, is engaged to the liner 54 via the first adhesive side resin composition (1BSRC). The particular ball-type bearing shown in Figure 15 includes a bore opening 62 so that it can be mounted on a shaft or rod. [Example]

[0043] Example of bearing liner preparation and bearing including bearing liner Non-limiting formulations of the first adhesive side resin composition 1BSRC and the second sliding side resin composition 2SSRC are shown in the table below.

[0044] [Table 1]

[0045] [Table 2]

[0046] The numbered components are as follows: 1 SR368D: Tris(2-hydroxyethyl) isocyanurate triacrylate, Sartomer USA (LLC Exton, Pa.) 2. Speedcure 4265: UV initiator supplied by Sartomer, Americas 3. Garamite 7305: Powdered rheological additive supplied by BYK-Chemie GmbH (Wesel, Germany) 4. Fibertec 9132: Milled glass fiber sold by Fibertec (Bridgewater, MA, USA) 5. Zonyl MP1300: PTFE powder supplied by Fluorogistx (Greenville, Del., USA) 6. Krytox GPL105: Perfluoropolyether oil sold by Miller Stephenson Chemicals

[0047] The ingredients of the 1BSRC were mixed in a Flacktek Speedmixer (Model DAC 150 FVZ) using industry standard mixing conditions. The ingredients of the 2SSRC were mixed in a Flacktek Speedmixer (Model DAC 150 FVZ) using industry standard mixing conditions.

[0048] The exemplary, non-limiting fabric selected was HT-527 fabric purchased from Stern and Stern Industries, which was cut into a rectangular test piece approximately 5 inches by 7 inches. This exemplary fabric is a woven fabric made from Nomex™ and PTFE fibers, with one side having a higher relative concentration of PTFE. A test fabric piece 30 (FIG. 8) was masked with masking tape at the 5-inch wide edges of the rectangular test piece, and a 1-inch wide, 5-inch long piece was covered with tape 32 on each side and edge. The fabric piece with the taped edges was placed on top of a larger backing material 34, with the darker sliding side of the HT-527 facing downwards and against the backing material. The sliding side of the exemplary fabric contained PTFE fibers. Therefore, the adhesive side of the HT-527 was now exposed. The longitudinal edges of the fabric were secured to the backing material with tape. This tape sealed the side edges of the fabric and prevented the 1BSRC from wicking onto the sliding surface of the fabric during subsequent coating. Any suitable inert backing material may be used.

[0049] Next, using a disposable polyethylene pipette with an approximately 0.080-inch-wide opening, parallel beads 36 of 5.0 grams of 1BSRC polymerizable resin were placed across the taped fabric, approximately seven beads across. See Figure 9. The beads were placed so that the first two were placed on the fabric adjacent to the 1-inch-wide tape at the width edge, the next bead was placed in the center of the width, and then two or more beads were placed in each half. Occasionally, the width of the beads was varied, and more or fewer beads were added to use all of the 5.0 grams of polymerizable resin mixture. Next, a 5.5-inch-wide rubber squeegee was used to spread the beads. This was done by starting at one width and drawing the squeegee along the edge of the tape at a relatively low angle (approximately 20-30 degrees) under approximately 5 pounds of hand pressure at a relatively slow hand speed until it reached the opposite taped edge. The squeegee was then reversed and the resin was applied in the same manner in the opposite direction. The squeegee was then lifted and positioned along the taped longitudinal edge, and the resin was spread again in the same manner. Finally, it was inverted again and spread again while turning back. This generally resulted in two passes (from one width side to the other width side and then back) and two passes from one length edge to the other length edge and back. After this coating process, a small amount of resin was usually left on the squeegee, which was then discarded.

[0050] The tape was then peeled lengthwise, and the fabric was then peeled away from the backing material (aluminum foil in the test example). As the tape was removed, some weft yarns were pulled away from the coated fabric surface, partially loosening it. The loose edge fibers were then trimmed away with very sharp scissors. As shown in Figure 10, a relatively small clipboard fabric holder 38, 5 inches wide and approximately 8 inches long, was used. This clipboard had clips attached to both ends (the clips were placed on one side of the clipboard and could be used to clamp each taped end of the test fabric 40, which had been coated with 1BSRC). The coated fabric assembly, attached to the clipboard, was then passed through a 6-inch-wide Heraeus UV conveyor equipped with a V-shaped bulb. The light source was set at a focal height of 1 3 / 8 inches from the bottom, and the conveyor was operated at approximately 20 feet per minute to promote partial polymerization.

[0051] The partially polymerized coated fabric was immediately removed, and the partially polymerized 1SSRC fabric was taped to a clean backing material (aluminum foil) as before, except this time the uncoated side of the HT527 was facing up. The 2SSRC was then coated in the same manner as previously used to coat the adhesive surface, except that the 2SSRC was used to coat what would eventually become the wear side of the fabric liner. After coating, it was removed as before, and the 2SSRC was placed face up on a double-sided clipboard and passed through a UV conveyor to promote partial polymerization of the 2SSRC.

[0052] The resulting liner was removed from the clipboard. The edges were lightly trimmed with a guillotine cutter, and the liner's weight and dimensions were measured to allow calculation of the percentage of resin and fabric in the liner. The adhesive surface was relatively rough and had a relatively high friction texture due to the presence of relatively small protruding glass fiber tips, while the sliding surface had a relatively low friction surface texture.

[0053] Bearings for AS81934 testing were made according to standard procedures with the above liners containing partially polymerized 1BSRC and 2SSRC, and a control bearing containing an X-1820 liner available from New Hampshire Ball Bearing. The 1BSRC surface of the inventive liner was bonded to the bearing surface using Henkel Loctite® AA331, after which the assembly was post-cured at 340°F for 16 hours.

[0054] As noted above, Figure 11 shows the results of high-pressure AS81934 military-specification sleeve bearing wear testing comparing a commercial bearing (43) AHJ08C012(L1) fitted with an X-1820 liner containing only PTFE fiber lubricant to the same bearing (45) AHJ08C012(L1) fitted with an X-1820 liner containing PTFE fiber lubricant and further containing vacuum-impregnated perfluoropolyether oil, i.e., Krytox GPL105 (disclosed in U.S. Patent Application Publication No. 20160348720A1). The PTFE and perfluoropolyether oil-containing bearing (45) made in accordance with U.S. Patent Application Publication No. 20160348720A1 exceeded the 0.0045-inch wear limit of AS81934 before the required life of 100,000 cycles, significantly exceeding the wear rate of the standard commercial bearing 43 containing only PTFE fiber lubricant. Thus, prior art bearings (45) made in accordance with U.S. Patent Application Publication No. 20160348720A1 having a lubricant combination of PTFE and perfluoropolyether oil do not meet high pressure military specification test wear requirements and have relatively poor wear life compared to commercial bearings (43) lubricated solely with PTFE fibers.

[0055] FIG. 12 shows the results of AS81934 bearing wear tests conducted under a nominal liner stress of 37,500 psi on a commercial bushing (line 42) made with HT-527 fabric and lined with the X-1820 liner described above, available from New Hampshire Ball Bearing. This commercial bushing from New Hampshire Ball Bearing is identified and sold as AHJ08C012(L1). This commercial bushing is compared to the wear results, shown in line 44, for bushings lined with the fiber liners described herein containing 1BSRC (see Table 1) and 2SSRC (see Table 2). Both lined bushings met the test requirement of less than 0.0045 inches of wear at 100,000 cycles. However, as seen in line 44, the bearing liners made with 1BSRC and 2SSRC described herein demonstrated an advantage, exhibiting approximately 30% lower wear.

[0056] 13A and 13B are graphs of the rotational torque measured during the AS81934 bushing wear test of FIG. 12. FIG. 13A shows the rotational torque over the first 25,000 cycles, and FIG. 13B shows the rotational torque over the full 100,000 cycle test. As shown at 46, the bearing liners herein made with 1BSRC and 2SSRC produced a maximum torque of 67 inch-pounds or less at zero cycle. This is a significant 44% reduction in torque at zero cycle compared to the commercial X-1820 lined bearing (see line 48). Therefore, the bearing liners herein made with 1BSRC and 2SSRC are generally considered to be bearing liners capable of providing a maximum torque of 80 inch-pounds or less at zero cycle, and more preferably 70 inch-pounds or less. Military specification test AS81934 requires that the torque limit of 79 inch-pounds not be exceeded at the end of the test. This requirement is intended to apply only at the end of the test due to the practical limitations of prior art lined military specification bearings, which, when first placed into service, require an undesirable break-in period before torque drops below 79 in-lbs. This is even more significant in that both liners are fabricated from the same base PTFE / nylon-containing fabric. Furthermore, when torque values ​​are measured from 1000 cycles, liners fabricated from the 1BSRC and 2SSRC of this invention exhibit approximately a 34% reduction in operating torque over the life of the bearing compared to the X-1820 liner.

Claims

1. A bearing, a. a first bearing surface configured to slide against a second bearing surface; b. A bearing liner positioned between the first bearing surface and the second bearing surface, the bearing liner having a first adhesive surface and a second sliding surface, the bearing liner comprising a woven or nonwoven fabric having a thickness of 0.005 inches to 0.030 inches, a basis weight of 5.0 grams per square foot to 70 grams per square foot, and an initial airflow permeability of 1 cfm to 100 cfm as measured by ASTM D737(2018). Including, c) the first adhesive surface of the bearing liner contains a first adhesive side resin composition comprising a polymeric resin containing glass and / or carbon fiber, the first adhesive side resin composition being adhered to one of the bearing surfaces; and d. A bearing, wherein the second sliding surface of the bearing liner contains a second sliding-side resin composition containing a polymeric resin and a lubricant, and the lubricant is dispersed in the second sliding-side resin composition at a level of 1.0 wt % to 60.0 wt %.

2. 10. The bearing of claim 1, wherein the lubricant comprises a mixture of polytetrafluoroethylene particulates and perfluoropolyether oil.

3. 3. The bearing of claim 2, wherein the polytetrafluoroethylene fine particles are present in the second sliding-side resin composition at a level of 15.0% by weight to 22.0% by weight, and the perfluoropolyether oil is present in the sliding-side resin composition at a level of 25.0% by weight to 33.0% by weight.

4. 2. The bearing of claim 1, wherein the glass and / or carbon fibers are present in the first bond side resin composition at a level in the range of 2.0% to 40.0% by weight.

5. 2. The bearing of claim 1, wherein the polymeric resin in the first adhesive side resin composition comprises polyacrylate, phenolic resin, aromatic polyamide, epoxy resin, polyimide, poly(amideimide), polyetherketone, polyetheretherketone, or polyester.

6. 2. The bearing according to claim 1, wherein the polymer resin in the second sliding-side resin composition includes polyacrylate, phenolic resin, aromatic polyamide, epoxy resin, polyimide, poly(amide-imide), polyether ketone, polyether ether ketone, or polyester.

7. 2. The bearing of claim 1, wherein the polymerized resin in the first adhesive side resin composition comprises a polymer of polymerized tris(2-hydroxyethyl)isocyanurate triacrylate monomer and polymerized trimethylolpropane triacrylate monomer.

8. 2. The bearing according to claim 1, wherein the polymer resin in the second sliding-side resin composition includes a polymer of polymerized tris(2-hydroxyethyl)isocyanurate triacrylate monomer and polymerized trimethylolpropane triacrylate monomer.

9. The bearing of claim 1 , wherein the first adhesive side resin penetrates and encapsulates the first adhesive surface of the bearing liner.

10. 2. The bearing of claim 1, wherein the second sliding side resin composition penetrates and encapsulates the second sliding surface of the bearing liner.

11. 10. The bearing of claim 1, which produces a maximum torque of 67 inch-pounds or less at zero cycle in an AS81934 bushing wear test.

12. 1. A method of making a bearing, comprising: a. providing a bearing having a first surface and a second surface, the first and second surfaces configured to slide relative to one another; b. providing a bearing liner having a first adhesive surface and a second sliding surface, the bearing liner comprising a woven or nonwoven fabric having a thickness of 0.005 inches to 0.030 inches, a basis weight of 5.0 grams per square foot to 70 grams per square foot, and an initial airflow permeability of 1 cfm to 100 cfm as measured by ASTM D737(2018); c) applying and partially polymerizing a first adhesive side resin composition containing a polymerizable resin containing glass and / or carbon fiber to the adhesive surface of the liner; d. applying a second sliding side resin composition containing a polymerizable resin to the second sliding surface of the bearing liner and partially polymerizing the second sliding side resin composition, the second sliding side resin composition containing a lubricant at a level of 1.0 wt % to 60.0 wt %; e. applying the first adhesive surface of the bearing liner containing a partially polymerizable resin to one of the first or second surfaces of the bearing, and adhering the first adhesive surface of the bearing liner to the first or second bearing surface. A method comprising:

13. 13. The method of claim 12, wherein the lubricant comprises a mixture of polytetrafluoroethylene particulates and perfluoropolyether oil.

14. The method according to claim 13, wherein the polytetrafluoroethylene fine particles are present in the second sliding-side resin composition at a level of 15.0 wt% to 22.0 wt%, and the perfluoropolyether oil is present in the sliding-side resin composition at a level of 25.0 wt% to 33.0 wt%.

15. 13. The method of claim 12, wherein said glass and / or carbon fibers are present in said first adhesive side resin composition at a level in the range of 2.0% to 40.0% by weight.

16. 13. The method of claim 12, wherein steps (c) and (d) are performed sequentially.

17. The partial polymerization in steps (c) and (d) is carried out by applying the first adhesive side resin composition and the second sliding side resin composition at a rate of 0.1 to 0.5 J / cm ２ (UVA), 0.05 to 0.5 J / cm ２ (UVB), 0.010-00.100J / cm ２ UVC and 0.5 to 5.0 J / cm ２ 13. The method of claim 12, wherein the method is initiated by exposure to UV light (UVV).

18. 13. The method of claim 12, wherein the polymerizable resin in the first adhesive side resin composition provides a polyacrylate, a phenolic resin, an aromatic polyamide, an epoxy resin, a polyimide, a poly(amideimide), a polyetherketone, a polyetheretherketone, or a polyester.

19. 13. The method of claim 12, wherein the polymerizable resin in the second sliding-side resin composition is a polyacrylate, a phenolic resin, an aromatic polyamide, an epoxy resin, a polyimide, a poly(amide-imide), a polyether ketone, a polyether ether ketone, or a polyester.

20. 13. The method of claim 12, wherein the polymerizable resin in the first adhesive side resin composition comprises a polymer of a mixture of polymerized tris(2-hydroxyethyl)isocyanurate triacrylate monomer and polymerized trimethylolpropane triacrylate monomer.

21. 13. The method of claim 12, wherein the polymerizable resin in the second sliding-side resin composition comprises a polymer of a mixture of polymerized tris(2-hydroxyethyl)isocyanurate triacrylate monomer and polymerized trimethylolpropane triacrylate monomer.

22. 13. The method of claim 12, wherein the bearing generates a maximum torque of 67 inch-pounds or less at zero cycle in an AS81934 bushing wear test.

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