Hybrid bearing assembly with rolling elements and plain bearing
A bearing assembly includes an outer race having an inner surface defining a concave contour and an inner race positioned in the outer race. The inner race has an inner surface defining a bore therethrough and an outer surface defining at least one groove circumscribing the outer surface. A plurality of rolling elements is rollably located in the groove and is in rolling contact with the inner surface of the outer race. A lubricious liner has an inner liner-surface and an exterior liner-surface, the exterior liner-surface being disposed on the inner surface defining the bore. The lubricious liner has a modulus of compression of a magnitude sufficient to allow misalignment of the inner liner-surface relative to the exterior liner-surface in response to a force applied thereto.
1. A flap hinge arm ( 40 ) of a fixed wing aircraft, comprising:
an arm ( 42 );
a connecting rod ( 44 ) pivotally connected to the arm ( 42 ) and pivotally connectable to a flap ( 54 ); and
a bearing assembly ( 10 , 110 , 210 , 310 , 410 ) positioned on the arm and connectable to a wing of the fixed wing aircraft, the bearing assembly comprising:
a bearing comprising:
an outer race ( 14 , 114 , 214 , 314 , 414 ) having an inner surface ( 26 ) defining a concave contour;
an inner race ( 12 , 112 , 212 , 312 , 412 ) positioned in the outer race ( 14 , 114 , 214 , 314 , 414 ), the inner race ( 12 , 112 , 212 , 312 , 412 ) having an inner surface ( 18 ) defining an inner race bore ( 22 ) therethrough and an outer surface ( 20 ) defining at least one groove ( 17 ) circumscribing the outer surface ( 20 );
a plurality of rolling elements ( 16 , 116 , 216 , 316 , 416 ) rollably located in the at least one groove and in rolling contact with the inner surface ( 26 ) of the outer race ( 14 , 114 , 214 , 314 , 414 ); and
a lubricious liner ( 36 , 136 , 236 , 336 , 436 ) having an inner liner-surface ( 36 B) and an exterior liner-surface ( 36 A), the inner liner-surface ( 36 B) defining a liner bore engaging an exterior surface ( 25 ) of a shaft ( 23 ) extending through the liner bore such that during normal operation of the bearing assembly, the shaft is fixed relative to the inner race, the exterior liner-surface ( 36 A) adhered to the inner surface ( 18 ), the lubricious liner ( 36 , 136 , 236 , 336 , 436 ) is an angular misalignment feature disposed between the shaft ( 23 ) and the inner race ( 12 , 112 , 212 , 312 , 412 ) and a torque dependent rotational fail-safe mechanism, the shaft being press fit into the liner bore;
wherein the angular misalignment feature is configured to accommodate angular misalignment between the shaft ( 23 ) and the inner race ( 12 , 112 , 212 , 312 , 412 ); and
wherein during normal operation the bearing assembly is configured to accommodate rotation of the outer race ( 14 , 114 , 214 , 314 , 414 ) relative to the inner race ( 14 , 114 , 214 , 314 , 414 ) and to rotationally fix the inner race ( 12 , 112 , 212 , 312 , 412 ) relative to the shaft ( 23 ) when a torque exerted on the outer race ( 14 , 114 , 214 , 314 , 414 ) is a first torque magnitude t 1 ,
wherein during anomalous operation or when the bearing seizes, the torque exerted on the outer race ( 14 , 114 , 214 , 314 , 414 ) is of a second torque magnitude that is selected from the group consisting of 1.1, 1.25, and 1.5 times the first torque magnitude t 1 and the torque dependent rotational fail-safe mechanism is configured to accommodate rotation of the inner race ( 12 , 112 , 212 , 312 , 412 ) relative to the shaft ( 23 ),
wherein the lubricious liner ( 36 , 136 , 236 , 336 , 436 ) has an axial length (L) and a continuous annular shape, the lubricious liner ( 36 , 136 , 236 , 336 , 436 ) comprising a thermoplastic resin or a thermosetting resin, the thermosetting resin selected from the group consisting of a phenolic resin, a polyester resin, an epoxy resin, a urethane resin, a polyurethane resin, and a polyimide resin, wherein the thermoplastic resin or the thermosetting resin comprises PTFE fibers and a fabric selected from the non-metallic material group consisting of cotton, polyester, glass fiber, carbon fiber, nylon, aramid material, and combinations of the foregoing materials, and
the lubricious liner ( 36 , 136 , 236 , 336 , 436 ) engaging the exterior surface ( 25 ) of the shaft ( 23 ) continuously and entirely circumferentially along the axial length (L) of the lubricious liner ( 36 , 136 , 236 , 336 , 436 ), and the exterior liner-surface ( 36 A) adhered to the inner surface ( 18 ) continuously and entirely circumferentially along the axial length (L) of the lubricious liner ( 36 , 136 , 236 , 336 , 436 ).
2. The flap hinge arm ( 40 ) of a fixed wing aircraft of claim 1 , further comprising:
a seal secured to the outer race and engaging a surface of the inner race; and
a retaining ring positioned on a side of the seal to secure the seal in place.
3. The flap hinge arm ( 40 ) of a fixed wing aircraft of claim 1 , wherein the plurality of rolling elements ( 16 , 116 , 216 , 316 , 416 ) are made from a material selected from the group consisting of stainless steel and corrosion resistant nitrided steel.
4. The flap hinge arm ( 40 ) of a fixed wing aircraft of claim 1 , wherein the outer race ( 14 , 114 , 214 , 314 , 414 ) and the inner race ( 12 , 112 , 212 , 312 , 412 ) are made from a material selected from the group consisting of stainless steel and corrosion resistant nitrided steel.
5. The flap hinge arm ( 40 ) of a fixed wing aircraft of claim 1 , wherein the plurality of rolling elements ( 16 , 116 , 216 , 316 , 416 ) is selected from a group consisting of spherical rollers, convex rollers, concave rollers and cylindrical rollers.
6. The flap hinge arm ( 40 ) according to claim 1 , wherein the arm comprises a rod end, wherein the outer race ( 14 , 114 , 214 , 314 , 414 ) is mounted in an eye of the rod end with a Grumman groove or is press fit.
7. A flap hinge arm ( 40 ) of a fixed wing aircraft, comprising:
an arm ( 42 );
a connecting rod ( 44 ) pivotally connected to the arm ( 42 ) and pivotally connectable to a flap ( 54 ); and
a bearing assembly ( 10 , 110 , 210 , 310 , 410 ) positioned on the arm and connectable to a wing of the fixed wing aircraft, the bearing assembly comprising:
a bearing comprising:
an outer race ( 14 , 114 , 214 , 314 , 414 ) having an inner surface ( 26 ) defining a concave contour;
an inner race ( 12 , 112 , 212 , 312 , 412 ) positioned in the outer race ( 14 , 114 , 214 , 314 , 414 ), the inner race ( 12 , 112 , 212 , 312 , 412 ) having an inner surface ( 18 ) defining an inner race bore ( 22 ) therethrough and an outer surface ( 20 ) defining at least one groove ( 17 ) circumscribing the outer surface ( 20 );
a plurality of rolling elements ( 16 , 116 , 216 , 316 , 416 ) rollably located in the at least one groove and in rolling contact with the inner surface ( 26 ) of the outer race ( 14 , 114 , 214 , 314 , 414 ); and
a lubricious liner ( 36 , 136 , 236 , 336 , 436 ) extending from a first end ( 36 C) to an opposing second end ( 36 D) and having an inner liner-surface ( 36 B) and an exterior liner-surface ( 36 A), the inner liner-surface ( 36 B) defining a liner bore engaging an exterior surface ( 25 ) of a shaft ( 23 ) extending through the liner bore such that during normal operation of the bearing assembly the shaft is fixed relative to the inner race, the exterior liner-surface ( 36 A) adhered to the inner surface ( 18 ), the lubricious liner ( 36 , 136 , 236 , 336 , 436 ) is an angular misalignment feature disposed between the shaft ( 23 ) and the inner race ( 12 , 112 , 212 , 312 , 412 ) and a torque dependent rotational fail-safe mechanism, the shaft being press fit into the liner bore;
wherein the angular misalignment feature is configured to accommodate angular misalignment between the shaft ( 23 ) and the inner race ( 12 , 112 , 212 , 312 , 412 ) upon application of a force perpendicular to the central axis (C) of the shaft ( 23 ), wherein upon application of the force, the central axis (C) of the shaft ( 23 ) is misaligned by a misalignment angle (a), the misalignment angle is from about 1 degree to about 15 degrees, the lubricious liner having a modulus of compression of a magnitude to allow misalignment through compression and expansion between an initial width, a compressed width and an expanded width, wherein compression of the first end ( 36 C) or the second end ( 36 D) of the lubricious liner ( 36 , 136 , 236 , 336 , 436 ) by at least a portion of the shaft ( 23 ) from the initial width to the compressed width corresponds to expansion at the respective first end ( 36 C) or the second end ( 36 D) of the lubricious liner ( 36 , 136 , 236 , 336 , 436 ) from the initial width to the expanded width, wherein the initial width of the lubricious liner is compressible to the compressed width and expandable to the expanded width by about 10% of the initial width, by about 25% of the initial width, or about 50% of the initial width;
wherein during normal operation the bearing assembly is configured to accommodate rotation of the outer race ( 14 , 114 , 214 , 314 , 414 ) relative to the inner race ( 14 , 114 , 214 , 314 , 414 ) and to rotationally fix the inner race ( 12 , 112 , 212 , 312 , 412 ) relative to the shaft ( 23 ) when a torque exerted on the outer race ( 14 , 114 , 214 , 314 , 414 ) is a first torque magnitude t 1 , wherein during anomalous operation or when the bearing seizes, the torque exerted on the outer race ( 14 , 114 , 214 , 314 , 414 ) is of a second torque magnitude that exceeds the first torque magnitude t 1 and the torque dependent rotational fail-safe mechanism is configured to accommodate rotation of the inner race ( 12 , 112 , 212 , 312 , 412 ) relative to the shaft ( 23 ).
8. The flap hinge arm ( 40 ) according to claim 7 , wherein the arm comprises a rod end, wherein the outer race ( 14 , 114 , 214 , 314 , 414 ) is mounted in an eye of the rod end with a Grumman groove or is press fit.