NASA Technical Reports Server (NTRS)

The Self-Lube® units are a versatile range of housings and inserts manufactured to NSK global specification for materials and quality – all cast iron housings supplied with regreasing facility, capable of taking up initial misalignment during assembly. METAFRAM® is the well-known brand of sintered self-lubricating bearings from Sintertech. 12 J.B. Wang, J. Lu, Q.J. Xue: Study on Tri-blogical Properties of SiC-Ni-Co-Mo-PbO High Temperature Self-lubricating Cermet Materials Vol. The shaft surface is critical due to the fact a shaft that is too rough acts like a file and, during movement, separates small particles from the bearing surface. This maintenance, performed on at least one unit per year at Jupia, involves investing in special materials and techniques that enable CESP to eliminate equipment weak points and overcome faults, defects and operational restrictions. Liquid-impregnated bearings are soaked in oil (often ordinary machine oil), which may make up 30 per cent of the finished bearing’s volume. An important distinction to make is that self-lubricating bearings are not bearings that come pre-applied with grease or oil lubricant – these bearings are instead referred to as prelubricated bearings. 3, load bearing layer 114 is laminated to structures 113 and intermediate layer 116, being bonded thereto by a layer of adhesive 120. 15. Plain bearing according to claim 13, characterized in that the sliding layer is applied to a metal back provided with a layer of porous sintered bronze. For additional information, including technical data, about our custom self-lubricating bearings, see the table below, or contact us directly. APAC leads the self-lubricating bearings market with nearly 50% market share. The member 1 serves as a deposit or store for a lubricant which is impregnated in the member 1. The remaining part of the bore 4, or at least a portion of said part, receives a sleeve-shaped plain bearing member 3 for rotatably supporting and guiding a rotary shaft 2 such as a disc record player turntable shaft. There are, of course, other self-lubricating bearings on the market. A plain bearing with such a sliding layer can be designed as an all-plastic bearing or with a metal back. This work indicated that some compounds that were good for room temperature wear would not be adequate for high-temperature applications. Alternatively, structures 113 provide a bearing 110, fabricated with a relatively thin load bearing layer 114, with a friction coefficient that remains relatively constant over its life. 16. Plain bearing according to claim 15, characterized in that the sintered bronze has a pore volume of 20 – 45%. Although none of the seven refurbished turbines have yet been disassembled for inspection, their performance is meeting expectations and CESP has not noticed any evidence of premature wear, such as oil leakage and increase of clearances in bearing assemblies of the Kaplan runner hub and in the guide vanes of the distributor mechanism. The bearings are also suitable for high temperatures. Bearing 110 of the present invention is preferably fabricated by providing a substrate 112 formed as a metallic sheet, with a cladding of bronze superimposed therewith to form an integral intermediate layer 116. Self-lubricating materials were installed in the bearings of the connection of regulating ring to linkages, bearings of the connection of linkages to guide vane levers, bearings of the regulating ring pulleys, servomotor rod bearings, and sliding segments of the regulating ring. With a temperature range of -40 to 210 degrees F, “NX” bearings are particularly effective in situations where lubrication cannot be frequently supplied. Bimet multi-layered bearings for grease lubrication. Combining the low friction of PTFE with the rigidity of high strength bronze alloys, LUBRON AQ bearings are capable of satisfying the most demanding requirements. Unlike regular bearings, self-lubricating bearings, or sintered bearings, are manufactured from metals with a high porosity of between 20 and 25% of their volume. A further objective of the present invention is to provide a manufacturing process for making self-lubricating bearings, wherein the bottom of the molding mold is connected with a bottom plate, the molding mold and the bottom plate are made of graphite, and the diameter of the spherical alloy particles ranges from 0.02 mm to 0.04 mm. As the bearing operates, the lubricant is released through pores in the sliding layer, lubricating the bearing surface. Said step of disposing a load bearing layer (c) further comprises the step of applying the load bearing layer to the slide bearing substrate using heat and pressure. Iron Oilite® are 100% iron oil-retaining bearings which provide an ideal solution in high stress low revolution applications. Immersion in liquid nitrogen is generally permitted provided the temperature of the bearing does not fall below -112 º F (-80º C). LUBRON AQ bearings can also be retained in the housings with countersunk set screws, dowel pins, or keyways.

Oil-filled sintered bronze bearings were first conceived in the 1930s, with self-lubricating metal-polymer bearings developed around 1950 and lubrication-free solid polymer bearings appearing in the 1960s. It is also necessary to collect lubricant, such as oil, which escapes from the bearing, and felt discs or suitably shaped centrifuging rings are used for this purpose. A wide range of lubricants are available to meet specific requirements within a temperature range of -60°C to 200°C, lubricant additives are also available to impart anti-wear properties in marginal lubrication conditions. A precise analysis of space requirements is critical to specifying self-lubricating bearings. Self-lubricating bearings eliminate the need for maintenance , lowering labor costs, and increase the service life of aerospace applications. The clearance for bearings moving in a to-and-fro motion should be the smallest possible (0.5-1 ‰). In high temperatures, the clearance should be larger than normal. Where split housings or a need for disassembly and reassembly make split bushings advantageous, LUBRON AQ bearings are available either matched (split before final machining providing perfect 180° halves) or unmatched (split after final machining varying slightly from perfect 180° halves). The sintered bronze layer also helps conduct heat away from the bearing surface. Meet your powder metal bearings needs. We can find Thordon Bearings on many applications in the field of transportation, like self-lubricating bushes for hinges and pulleys for trucks and special vehicles. The invention is based on the knowledge that the performance under lubrication-free conditions can be significantly increased if a certain filler combination is used in conjunction with PTFE, which has PbO and metal fluoride. Some of this discussion was presented earlier in Section 7.4.3. Some studies of wear and friction control temperature to a specific level (usually room temperature”), some report temperatures, and some studies report nothing. Even though LUBRON AQ bearings are extremely durable, care must be taken to ensure that the lubricated bearing surfaces are not damaged before or during installation. 11. Bearing material according to one of claims 6 to 10, characterized in that the solid lubricants are MoSj or boron nitride. The bearings of the present invention are more resistant to mechanical stresses than standard NG. In this regard, bearings of the present invention were fabricated using a steel substrate 0.8 mm thick with bronze intermediate layer 116 and PTFE bearing layer 114 of the dimensions shown and described hereinabove with respect to FIG. These bearings are solid or hollow cylinders, to be machined to final dimensions when the system is not ready for standard SELFOIL® bearings. Specified and approved by engineering design firms and water power authorities worldwide, LUBRON AQ bearings are the proven choice for hydro pump-turbine and dam gate applications. Stainless roller wheels are also available from Lubron Bearing Systems in combination with self-aligning spherical bearings. Friction coefficient is 0.03~0.15. As shown in Figure 1 & 2, the coefficient decreases with load but increases under low temperature. Temperature — Vendors will rate their bearings for operation in certain ranges. Furthermore, the arrangement illustrated ensures that the bearing clearance 6 between the shaft 2 and the member 3 is not sucked empty of lubricant by the suction effect of the porous member 1, after assembly of the bearing or when the shaft is stationary or rotating at low speeds. Accurate alignment is particularly important for self-lubricating bearings. This kind of material provides a maintenance-free solution and is particularly good for high load and intermittent of oscillating motion. The porous bronze layer is impregnated with a polymer such as PTFE (polytetrafluoroethylene), with a top layer or lining of polymer disposed thereon. LUBRON AQ spherical bearing assemblies consist of an inner component (gimbal) with a cylindrical inside diameter for shaft rotation and a spherical convex outside diameter, and a two-piece outer component (race) with a mating spherical concave inside diameter and a cylindrical concave outside diameter for mounting in a housing. G-METAL cylindrical bearings can be made from 8 mm to 280 mm in diameter. Wear is a surface phenomenon that results in the gradual deterioration of contacting surfaces through friction. There are three types of self-lubricating plain bearings used today. The utility model relates to a kind of oil-less self-lubricating bearing.

  1. The method of claim 1, wherein said load bearing layer comprises a lubricious plastic material. The bearings come in any shape and size to facilitate installation and maintenance. The key feature of these bearings is the coating polyoxymethylene (POM) layer with its relative thickness of 0.3 mm with lubrication recesses for lubricating grease. This aspect tends to make the Norglide bearings undesirable for use in applications that rely on electrical continuity such as, for example, electrostatic painting in the automotive and other metal fabricating industries. A new type of high temperature self-lubricating Ti-Al alloy bearing materials is proposed. A kind of oil-less self-lubricating bearing comprises bearing main body, and the top of described bearing main body is provided with bearing housing, and the inside of bearing housing is provided with steel ball, is provided with one deck self-lubricating layer between the internal surface of steel ball and bearing housing. Preferred materials for these applications are those that, for example, have a coefficient of static friction (μ) similar to that of PTFE (approximately 0.04-0.10). Moreover, the bearing’s coefficient of friction remains low and nominally constant over its life, even, surprisingly, once load bearing layer 114 is worn down to, and into, structures 113. Another further objective of the present invention is to provide a manufacturing process for making self-lubricating bearings, wherein two thirds of the melting temperature of the alloy’s main constituent ranges from 750° C. to 850° C. Whether you are an OEM motion designer seeking to design a maintenance-friendly system or a maintenance engineer replacing a bearing that requires manual lubrication, the design and application factors you must consider are similar. There are many advantages to opting for self-lubricating sintered bearings over the other types available, and it is important to note these if you want to make the ideal bearing selection for your application. Available in both inch and metric sizes, LUBRON AQ bearings are supplied finished machined to meet the exacting requirements of each application. The multi-layer materials differ from the all-plastic materials, for example, by a negligible tendency to cold flow under load, by a much better thermal conductivity and associated by significantly higher possible pv values. Besides contaminating the grease with solid materials (sand), the presence of water can cause corrosion on the guide vane trunnion, affecting bearing performance and lifetime. Graphite plugged bronze: Graphite is a good solid lubricant that is normally added to a bronze type bearing. During using process, the solid lubricant and the bearing friction by the friction heat, to form the excellent condition of lubrication of oil and powder, thus not only protecting the bearing from wearing, but also leading the solid lubricating performance to be perpetual, the hardness is one times higher that that of general brass, the abrasion resistance also can be improve one times, thereby being more suitable for heavy duty low speed working condition, and having good wear resistance, corrosion resistance, anti-chemical performance and extremely low friction coefficient. Currently, this technology is only available with injection-molded, self-lubricating polymer bearings. As mentioned, the porous member 1 may be in the form of a sintered member whose starting material in a loose condition was sintered without additional pressure, in contrast to the sintered member of the above-discussed previously bearing member which was pressed and sintered using high pressure in a mold. Self-lubricating bearings are comprised of a variety of polymers that utilize internal lubrication or inherent polymer properties to enhance wear life without the need for grease. Steps were also taken to modify PTFE to make it easier to compound into other materials. Oilite bearings have a rich history dating back to the 1930’s when they were developed by Chrysler. In low speed, high load applications, LUBRON AQ solid lubricants have a typical coefficient of friction between 0.02 to 0.10, depending on a variety of factors affecting performance. LUBRON AQ30 lubricants are machined flush with the bronze substrate surface. The self-lubricating bearing known from DE 35 16 649 AI has in the PTFE matrix thinly rolled sheet or scale-like particles which form streaks, which consist of a plurality of spaced-apart layers which are essentially parallel to the surface of the Extend sintered metal layer.

Graphite is used in products for the following reasons: conductivity, EMI shielding, lubricating coatings, self-lubricating bearings, lubricants, heat, chemical, and water resistance, flame retardancy, release properties, and pigmentation. 7 M.M. Shi: Solid Self-lubricating Materials Vol. The main advantages of material when compared to PTFE foil are its higher load capacity, as PTFE foils can be deformed when submitted to high loads, and its longer lifetime. In this regard, the bearings are provided with a relatively low coefficient of friction, long bearing life, resistance to creep and mechanical stresses, and are electrically and thermally conductive. One form of self-lubricating plain bearing comprises a metal capillary bearing member formed from metal powder with or without graphite by pressing under a high pressure in a mold, followed by sintering in a hydrogen atmosphere. Whenever reference is made to bronze with graphite, it is safe to assume that bronze plugs have been embedded in the bronze bearings. Moreover, the coefficient of friction of the NORGLIDE bearing may be lower than other prior art bearings due to the ability to utilize reduced filler content or fillers that have less negative impact on the coefficient of friction. In operation of the bearing the lubricant is sucked out of the pores of the bearing member and supplied to the bearing surface of the sintered member and the shaft, by the rotating shaft, as a result of suction and an increase in temperature, due to capillary action, according to the speed of rotation of the shaft. Bearings should be sized to accommodate the total applied load without exceeding the maximum design load. 11. A bearing as set forth in claim 10 wherein said porous member comprises spheroidal sintered bronze. The advantages conferred by this self-lubricating layer include a low coefficient of friction and high load capacity — up to 36,260 pounds per square inch (psi) compared to the 1,450 psi achievable with sintered bronze bearings. 7. A bearing as set forth in claim 1 wherein the porous member comprises spheroidal sintered bronze. A preferred material for the member 1 is a sinter material comprising spheroidal particles, more particularly bronze, thereby making it possible to produce porosity which is uniformly distributed throughout the sintered member so that there is substantially no possibility of regions of different suction capability within the porous member. In another application, a swinging hinge assembly used to support PVC swinging strip doors — used for quick loading bay access — has been using maintenance-free, all-plastic plain bearings since 1998 with no problems. In the rolling process, the pores of this layer are filled with polytetrafluoroethylene (PTFE) mixed with friction and wear-reducing additives. The third, lubrication-free option is to use injection-molded solid polymer bearings. In order to properly integrate the bearing into a linear motion system, the linear shafting needs to be cleaned with a 3-in-1® type of oil to ensure a clean transfer of material. 16. The method of claim 15, wherein said load bearing layer is applied to said substrate by heat and pressure. These are porous, sintered-metal bearings. A method is provided for fabricating a self-lubricating bearing as a laminate of a metallic substrate and a series of raised structures formed integrally therewith and extending orthogonally therefrom. With the correct lubrication, slide bearings almost non-wearing. The lubrication (typically oil or grease) is NOT added to the original bearing design. Proper lubrication delivery is critical for the operation of ball bearings, and most require continued maintenance for re-lubrication. 33 T.S. Li: The Development of Gradient Self-lubricating Bearing Materials Vol. Reinforcing fillers are added to increase the lubricant’s resistance to deformation under load and distortion due to elevated temperatures. 2. Bearing layer 114 may be subsequently formed by laminating a conventional sheet of lubricious material, such as PTFE, using a suitable adhesive as described hereinabove. It is a self-lubricating bearing with graphite plugged to base metal. Self-lubrication allows this type of sliding bearing to work under hydrodynamic conditions, resulting in a very low friction coefficient. A bearing surface means such as a sleeve for supporting the shaft is disposed in the bore adjacent to the porous member and extends outwardly of the bore from the porous member. The study provides a decisive view on the self-lubricating bearing market by segmenting the market based on applications.

Oilite bearings continue to set the standard for all other self-lubricating bearings and Bowman International is proud to be the sole supplier of genuine Oilite bearings in the UK and Europe in partnership with Beemer Precision Inc. Motion system designers are increasingly outfitting round and profile rails with self-lubricating bearings that can significantly, reduce cost of ownership, improve performance and deliver virtually maintenance-free operation. The primary objective of the present invention is to provide a self-lubricating bearing, which is a hollow cylindrical body with an axial hole in its center, exhibiting a structure formed by sintering a multiple of spherical alloys particles with a multiple of pores among them to receive lubricating oil. Replacement of the bearings, shafts, and even motors and other parts can be very costly. LUBRON AQ bearings provide proven performance for demanding underwater applications. Self-lubricating bearings save time and money on preventative maintenance, and require no hazardous waste from the lubricant, disposal, or cleanup to handle. Standard Oilite oil retaining tin bronze is the generally specified material. Solid polymer bearings are also impervious to corrosion and have a high load capacity. The dry-running nature of these bearings means dirt particles do not stick to the surface, but instead deflect off it. For this reason, optimal performance can be maintained even in extremely dirty environments. These bearings may also be used in lighter duty applications such as multiple bar linkages commonly utilized in the automotive industry for trunk deck lid and hood hinges. 13 J.S. Han, J.B. Wang, S.W. Zhang: The Friction of Self-lubricant Fe-Mo-CaF2 at High Temperature Vol. A further object of the invention is a self-lubricating plain bearing which, while providing smooth running due to satisfactory lubrication, comprises components which require only comparatively simple operations for manufacture thereof. This transfer process creates a film that provides lubrication and reduces friction over the length of the rail or shaft. 17. Plain bearing according to one of claims 15 or 16, characterized in that the sintered bronze has 5-15% tin. Tremendous progression in the bearing lubrication technology has led to the growth of self-lubricating plain bearings that are lightweight and incur low maintenance cost, enabling end-users to optimize the productivity of various bearing-based applications competently and cost-effectively. LUBRON AQ lubricants consist of PTFE (polytetrafluoroethylene) and epoxy resins, hardeners, metallic and fibrous fillers, specially compounded to achieve optimum bearing performance. Application of the load bearing layer may be performed either before or after flanging one or both ends thereof. Therefore, anything affecting surface temperature – coefficient of friction, running clearance, hardness and surface finish of the mating material – will also affect the PV limit. The mean size of the pores in the porous member may be larger than the clearance between the shaft and the porous member, while the capillary flow suction action applied to the lubricant to cause it to flow into said bearing clearance is adapted to the relationship S12 >S13 >S3, wherein S12 is the suction capability of the bearing clearance between the shaft and the bearing surface means, S13 is the suction capability of said clearance between the shaft and the porous member, and S3 is the suction capability of the porous member. The bronze-lubricant inner structure supplies a permanent reservoir of lubricant for continuous restoration of the low friction bearing surface. The “NU” self-lubricating bearings are used where excessive friction is a concern. Self-aligning spherical bearings are designed to accommodate radial loads and some misalignment. We currently stock many powder metal bearings manufactured for customer release schedules including JIT and blanket orders. An additional drawback of this concentration gradient is that any operation that removes material from the bearing layer, such as the common practices of boring, broaching or burnishing the bearings to size after installation, generally cannot be accomplished without a reduction in bearing performance. Extremely precise applications—plastic bearings have a higher running clearance than ball bearings, sometimes 0.025 mm to 0.055 mm, and, therefore, are not ideal for applications needing extreme precision. Simply put, the porous material used to manufacture these bearings is impregnated with lubricating oil, which reduces friction between the bearing and the shaft.

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