Oil film bearing
An oil film bearing for supporting a roll neck in a rolling mill, suitable in particular for transmitting high bearing forces when the bearing partners are slightly and slowly moved with respect to each other, has a bearing surface into which are incorporated rods made of a friction-reducing material (e.g., low friction compounds), which extend in a substantially perpendicular direction to the bearing surface. The rods are deformed during heat processing to define a bearing surface. The bearing partner, such as a roll sleeve, rests on the free face of the deformed rods.
1. An oil film bearing for rotatably supporting a roll neck in a rolling mill, said oil film bearing comprising:
a rotating section having a generally cylindrical outer surface;
a generally cylindrical, fiber-reinforced polymer bushing comprising polytetrafluoroethylene (PTFE) or ultra high molecular weight polymer (UHMW) and providing a generally cylindrical bearing surface, wherein the outer surface of the rotating section is rotatably supported on a film of oil on the bearing surface; and
a plurality of oil conduits for supplying pressurized oil between the outer surface of the rotating section and the polymer bushing to establish the oil film,
wherein the bearing surface is defined by a plurality of heat deformed PTFE or UHMW elements, wherein each of the plurality of elements is received within an opening in a bearing block, wherein the elements are heat-deformed in a manufacturing process to define the generally cylindrical bearing surface, with said manufacturing process including:
inserting said PTFE or UHMW elements into boreholes of the bearing block,
heating the PTFE or UHMW elements to a temperature resulting in a degree of plasticity,
inserting a die into the bushing, and
outwardly forcing the die toward the bearing block to deform the heated PTFE or UHMW elements into a generally cylindrical form.
2. The oil film bearing of claim 1 , wherein the boreholes are perpendicular to the bearing surface or offset relative to the bearing surface.
3. An oil film bearing for rotatably supporting a roll neck in a rolling mill, said oil film bearing comprising:
a rotating section having a generally cylindrical outer surface;
a generally cylindrical, fiber-reinforced polymer bushing comprising polytetrafluoroethylene (PTFE) or ultra high molecular weight polymer (UHMW) and providing a generally cylindrical bearing surface, wherein the outer surface of the rotating section is rotatably supported on a film of oil on the bearing surface; and
a conduit for supplying pressurized oil between the outer surface of the rotating section and the polymer bushing to establish the oil film,
wherein the polymer bushing is a generally homogenous plate having a generally smooth surface and a plurality of pins, wherein the plate is heat-deformed in a manufacturing process to define the generally cylindrical bearing surface, with said manufacturing process including:
inserting said plurality of pins into a plurality of boreholes of the bearing block,
heating the polymer bushing to a temperature resulting in a degree of plasticity,
inserting a die into the polymer bushing, and
forcing the die toward the bearing block to deform the heated polymer bushing into a generally cylindrical form.
4. The oil film bearing of claim 3 wherein the plate is defined using a powdered PTFE or UHMW material.
5. The oil film bearing of claim 4 further comprising:
sintering the plate of powdered PTFE or UHMW material.
6. An oil film bearing for rotatably supporting a roll neck in a rolling mill, said oil film bearing comprising:
a rotating section having a generally cylindrical outer surface;
a generally cylindrical, fiber-reinforced polymer bushing comprising polytetrafluoroethylene (PTFE) or ultra high molecular weight polymer (UHMW) and providing a generally cylindrical bearing surface, wherein the outer surface of the rotating section is rotatably supported on a film of oil on the bearing surface; and
a conduit for supplying pressurized oil between the outer surface of the rotating section and the polymer bushing to establish the oil film, wherein the bearing surface is defined by a plurality of heat deformed PTFE or UHMW elements, wherein each of the plurality of elements is received within an opening in a bearing block, wherein the elements are heat-deformed in a manufacturing process to define the generally cylindrical bearing surface, with said manufacturing process including:
inserting said PTFE or UHMW elements into boreholes of the bearing block,
heating the PTFE or UHMW elements to a temperature resulting in a degree of plasticity, and
outwardly forcing the PTFE or UHMW elements into a generally cylindrical form.
7. An oil film bearing for rotatably supporting a roll neck in a rolling mill, said oil film bearing comprising:
a rotating section having a generally cylindrical outer surface; and
a generally cylindrical, fiber-reinforced polymer bushing comprising polytetrafluoroethylene (PTFE) or ultra high molecular weight polymer (UHMW) and providing a generally cylindrical bearing surface, wherein the outer surface of the rotating section is rotatably supported on a film of oil on the bearing surface;
wherein the polymer bushing is defined as a generally homogenous plate having a generally smooth surface and a plurality of protuberances sized to be inserted into a plurality of boreholes in a bearing block, wherein the plate is heat-deformed in a manufacturing process including:
heating the plate to a temperature resulting in a degree of plasticity, and
deforming the plate into a generally cylindrical form.
8. The oil film bearing of claim 7 wherein the plate is formed of powdered PTFE or UHMW material.
9. The oil film bearing of claim 8 wherein the powdered PTFE or UHMW material is sintered.
10. The oil film bearing of claim 7 wherein said deforming the plate includes using an external die to change the shape of the plate.
11. The oil film bearing of claim 7 wherein said deforming the plate includes using a hydrostatic form to compact the plate.
12. The oil film bearing of claim 7 wherein the plurality of protuberances is a plurality of cylindrical pins.
13. The oil film bearing of claim 7 wherein the plate is initially a preform of powdered PTFE or UHMW material.
14. The oil film bearing of claim 13 wherein the powdered preform is compacted and sintered away from the bearing block and subsequently inserted into the bearing block.
15. The oil film bearing of claim 13 wherein the powdered preform is compacted and sintered after the preform is inserted into the bearing block.
16. The oil film bearing of claim 7 wherein the polymer bushing includes a conduit for supplying pressurized oil at the bearing surface.