The present technology is directed to a self-lubricating bearing and more particularly to a self-lubricating bearing having a metallic outer ring, a self-lubricating liner, and a metallic inner member with a physical vapor deposition coating thereon. The self-lubricating liner is bonded to the outer ring. Optionally, a lubricant is disposed between the self-lubricating liner and the physical vapor deposition coating.
Various types of bearings are used in aircraft applications where vibrations are known to occur due to bearing wear. When vibration of the aircraft airframe occurs, it can be detected by the persons inside the aircraft. Depending on the root cause of the vibration, it may be experienced either as physical movement, noise, or both movement and noise. These occurrences can cause passenger distress and malaise. Furthermore, any vibration can cause increased wear of components. As the airframe vibration increases, it causes premature failure of the bearings. Options for replacement of the failed bearing is limited because of space constraints. Thus, there is a need for a bearing that is resistant to wear.
In addition, there are environmental standards that limit the use of certain materials in components such as bearings. For example, REACH (i.e., Registration, Evaluation, Authorization and Restriction of Chemicals) is a regulation of the European Union adopted to improve the protection of human health and the environment from the risks that can be posed by chemicals while enhancing the competitiveness of the EU chemicals industry. Thus, certain materials must be avoided in the design of bearings.
There is disclosed herein a self-lubricating bearing that includes an outer ring having a concave inside surface defining an interior area of the outer ring. The self-lubricating bearing has an inner member having a convex exterior surface. The inner member is disposed at least partially in the interior area. The convex exterior surface has a physical vapor deposition coating thereon. The self-lubricating bearing has a self-lubricating liner bonded to the concave inside surface. The outer ring comprises a first metallic alloy, and the inner member comprises a second metallic alloy.
In some embodiments, a chemical composition of the first metallic alloy and a chemical composition of the second metallic alloy are the same.
In some embodiments, the chemical composition includes a precipitation hardened stainless steel.
In some embodiments, the precipitation hardened stainless steel includes an AMS 5643 17-4PH stainless steel or an AMS 5629 13-8 PH stainless steel.
In some embodiments, the precipitation hardened stainless steel includes an AMS 5643 17-4PH stainless steel heat treated per 17-4PH H1150.
In some embodiments, the chemical composition includes a martensitic stainless steel.
In some embodiments, the martensitic stainless steel includes a 440C stainless steel or an AMS 5630, AMS 5880 or AMS 5618 stainless steel.
In some embodiments, the martensitic stainless steel is heat treated to HRc 55 to 62.
In some embodiments, a chemical composition of the first metallic alloy includes a precipitation hardened stainless steel, and a chemical composition of the second metallic alloy includes a martensitic stainless steel.
In some embodiments, the precipitation hardened stainless steel includes an AMS 5643 17-4PH stainless steel or an AMS 5629 13-8 PH stainless steel, and the martensitic stainless steel comprises a 440C stainless steel or an AMS 5630, AMS 5880 or AMS 5618 stainless steel.
In some embodiments, the precipitation hardened stainless steel includes an AMS 5643 17-4PH stainless steel heat treated per 17-4PH H1150.
In some embodiments, the martensitic stainless steel is heat treated to HRc 55 to 62.
In some embodiments, the self-lubricating bearing further includes a lubricant disposed between the self-lubricating liner and the physical vapor deposition coating.
In some embodiments, the lubricant includes a silicone grease with a plurality of first self-lubricating particles dispersed therein.
In some embodiments, the physical vapor deposition coating includes chromium nitride, titanium nitride, tungsten carbide or zirconium nitride.
In some embodiments, the physical vapor deposition coating is coated on the convex exterior surface via at least one of cathode arc evaporation, magnetron sputter, electron beam evaporation, ion beam sputter, and laser ablation.
In some embodiments, the plurality of first self-lubricating particles includes polytetrafluoroethylene.
In some embodiments, the polytetrafluoroethylene includes at least one of a powder, a floc and fibers.
In some embodiments, the self-lubricating liner includes a woven material with a thermosetting resin embedded therein and a plurality of second self-lubricating particles dispersed in the resin.
In some embodiments, the woven material includes a fabric comprising at least one of fiberglass, polyethylene terephthalate, polyester, nylon, cotton, meta-aramid material, polytetrafluoroethylene and aromatic polyamide fibers.
In some embodiments, the self-lubricating liner includes a thermally-consolidated, machinable, moldable non-woven material.
In some embodiments, the non-woven material includes a plurality of second self-lubricating particles integral to the non-woven material or as an additive to a resin.
In some embodiments, the resin includes polyester, epoxy, phenolic, urethane, polyimide, thermoplastic polymers or a thermoset polymer.
In some embodiments, the self-lubricating bearing is a spherical bearing or a journal bearing.
In some embodiments, the outer ring has at least one axial split therein.
In some embodiments, the inner member has at least one axial split therein.
In some embodiments, the self-lubricating bearing has a diametral clearance between the inner member and the physical vapor deposition coating of less than 0.1 mm after 30,000,000 cycles of operation.
In some embodiments, the inner member has a cylindrical bore extending axially therethrough, the bore is defined by a concave interior surface having another self-lubricating liner adhered thereto, the self-lubricating bearing further includes a shaft extending through the bore and another physical vapor deposition coating on a cylindrical exterior surface of the shaft, and the shaft is in sliding relation to the inner member.
In some embodiments, the self-lubricating bearing further includes a lubricant disposed between the other self-lubricating liner and the other physical vapor deposition coating.
In some embodiments, the other physical vapor deposition coating includes chromium nitride, titanium nitride, tungsten carbide or zirconium nitride.
In some embodiments, the other physical vapor deposition coating is coated on the cylindrical exterior surface via at least one of cathode arc evaporation, magnetron sputter, electron beam evaporation, ion beam sputter, and laser ablation.
As shown in
The self-lubricating bearing 10 includes an outer ring 12 having an interior area 14 defined by a concave inside surface 16 of the outer ring 12. The outer ring 12 is manufactured from a stainless steel (e.g., martensitic steel, ferritic steel, precipitation hardened steel, austenitic steel, austenitic-ferritic steel), corrosion-resistant superalloy (e.g., nickel based, cobalt based, iron based), or titanium-based alloys. In some embodiments, the stainless steel is a precipitation hardened stainless steel and is an AMS 5643 17-4PH stainless steel or an AMS 5629 13-8 PH stainless steel. In some embodiments, the AMS 5643 17-4PH stainless steel is heat treated per 17-4PH H1150.
The self-lubricating bearing 10 includes an inner member 20 having a convex exterior surface 22. The inner member 20 is disposed at least partially in the interior area 14. The inner member 20 is manufactured from a stainless steel (e.g., martensitic steel, ferritic steel, precipitation hardened steel, austenitic steel, austenitic-ferritic steel), corrosion-resistant superalloy (e.g., nickel based, cobalt based, iron based), or titanium-based alloys. In some embodiments, the stainless steel is a precipitation hardened stainless steel such as AMS 5629 13-8 PH stainless steel or a martensitic steel per AMS5630, AMS5880, or AMS5618. In some embodiments, the martensitic steel per AMS5630, AMS5880 or AMS5618 is heat treated to HRc 55 to 62. The convex exterior surface 22 has a physical vapor deposition coating 24 thereon (see
In some embodiments, the outer ring 12 is made from a first metallic alloy and the inner member 20 is made from a second metallic alloy. In some embodiments, the chemical composition of the first metallic alloy and the chemical composition of the second metallic alloy are the same. In some embodiments, the chemical composition of the first metallic alloy and the second metallic alloy consist of a precipitation hardened stainless steel. The precipitation hardened stainless steel is, for example, an AMS 5643 17-4PH stainless steel or an AMS 5629 13-8 PH stainless steel. In some embodiments, the precipitation hardened stainless steel is, for example, an AMS 5643 17-4PH stainless steel heat treated per 17-4PH H1150. In some embodiments, the chemical composition of the first metallic alloy and of the second metallic alloy is a martensitic stainless steel such as 440C stainless steel (e.g., having a composition of 78-83.1% iron, 16-18% chromium 1-1.2% carbon 1% (max) silicon, 1% (max) manganese, 0.8% molybdenum, 0.04% phosphorus and 0.02% sulfur).
In some embodiments, where the chemical composition of the first metallic alloy and the second metallic alloy are the same, the chemical composition of the first metallic alloy and the second metallic alloy is, for example, a martensitic stainless steel. The martensitic stainless steel is a 440C stainless steel or an AMS 5630, AMS 5880 or AMS 5618 stainless steel. In some embodiments, the martensitic stainless steel is heat treated to HRc 55 to 62.
In some embodiments, the chemical composition of the first metallic alloy and the chemical composition of the second metallic alloy are different. For example, the chemical composition of the first metallic alloy is a precipitation hardened stainless steel and the chemical composition of the second metallic alloy is a martensitic stainless steel. In some embodiments, the precipitation hardened stainless steel is an AMS 5643 17-4PH stainless steel or an AMS 5629 13-8 PH stainless steel and the martensitic stainless steel is an AMS 5630, AMS 5880 or AMS 5618 stainless steel. In some embodiments, the precipitation hardened stainless steel is 440C stainless steel or an AMS 5643 17-4PH stainless steel heat treated per 17-4PH H1150. In some embodiments, the martensitic stainless steel is heat treated to HRc 55 to 62.
A self-lubricating liner 30 is bonded to the concave inside surface 16. In some embodiments, the physical vapor deposition coating 24 is a chromium nitride material. In some embodiments, the physical vapor deposition coating 24 is a titanium nitride material. In some embodiments, the physical vapor deposition coating 24 is a tungsten carbide material. In some embodiments, the physical vapor deposition coating 24 is a zirconium nitride material. The physical vapor deposition coating 24 is performed via cathode arc evaporation, magnetron sputter, electron beam evaporation, ion beam sputter or laser ablation.
In some embodiments, a lubricant 40 (e.g., silicone grease) with a plurality of first self-lubricating particles 44 (see
In some embodiments, the inner member 20 has a cylindrical bore 28 extending axially therethrough and concentric with a longitudinal axis B of the self-lubricating bearing 10. The bore 28 is defined by a concave interior surface 29 of the inner member 20. In some embodiments, a shaft 50 extends through the bore 28 and a cylindrical exterior surface 52 of the shaft 50 engages the concave interior surface 29 of the inner member 20. In some embodiments, the shaft 50 is press fit into the bore 28. However, in some embodiments, the cylindrical exterior surface 52 of the shaft 50 axially and/or rotationally slidingly engages the concave interior surface 29.
As shown in
As best shown in
While the self-lubricating liner 30 is shown and described as having a woven structure 80, the present invention is not limited in this regard as in some embodiments, the self-lubricating liner 30 is a thermally-consolidated, machinable, moldable or non-woven material that has a reinforced polymer matrix composite with the plurality of second self-lubricating particles 84 integral to the non-woven material and/or as an additive to the matrix.
While
The bushing 112 is press fit into a cylindrical inside surface 68 of a housing 66. A shaft 120 extends through the bore 114. The shaft 120 has a cylindrical exterior surface 122. In some embodiments, the shaft 120 is manufactured from a stainless steel (e.g., martensitic steel, ferritic steel, precipitation hardened steel, austenitic steel, austenitic-ferritic steel), corrosion-resistant superalloy (e.g., nickel based, cobalt based, iron based), or titanium-based alloy. In some embodiments, the stainless steel is a precipitation hardened stainless steel and is an AMS 5643 17-4PH stainless steel or an AMS 5629 13-8 PH stainless steel. The cylindrical exterior surface 122 has a physical vapor deposition coating 24 thereon (similar to that described herein with reference to the self-lubricating bearing 10 illustrated in
As shown in
As shown in
The plot 201 is of diametral clearance DC versus cycles for a prior art baseline bearing. The plot 201 illustrates that the prior art bearing has a diametral clearance DC of about 0.5 mm after about 2,000,000 cycles, which exceeds operational wear limits.
Plots 202 is the test data for the spherical self-lubricating bearing 10 according to an embodiment of the present invention with a chromium nitride physical vapor deposition coating 24 on the inner member 20 and with the silicone grease lubricant 40, with the plurality of first self-lubricating particles 44 dispersed therein, disposed between the self-lubricating liner 30 and the physical vapor deposition coating 24. As shown in plot 202, the self-lubricating bearing 10 has a diametral clearance between the self-lubricating liner 30 and the physical vapor deposition coating 24 of less than 0.1 mm after 30,000,000 cycles of operation. While the endurance tests were performed for the spherical self-lubricating bearing 10 of the present invention, the test results are also applicable to the journal type self-lubricating bearing 100 illustrated in
In some embodiments, the inner member 20 has a split configuration in which the inner member 20 has one or more axial splits therein. For example, in the embodiment shown in
In some embodiments, the outer ring 12 has a split configuration in which the outer ring 12 has one or more axial splits therein. For example, in the embodiment shown in
Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the appended claims.
This application is a non-provisional application of, and claims priority to U.S. Provisional Patent Application No. 63/280,189, entitled “Self-Lubrication Bearing,” filed on Nov. 17, 2021, the entire contents of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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63280189 | Nov 2021 | US |