Thrust bearing with tilting pad
A thrust bearing for an electric submersible pump includes a ring or mounting clips that include spring elements and retaining tangs, and pads each including a fluid interface surface and a pivot surface. Slots are formed between the pivot surface and the fluid interface surface. The spring elements engage the slots to secure the pads to the ring or mounting clips. The thrust bearing further includes a housing including an axial surface interfacing with the pivot surfaces. The ring or mounting clips are affixed to the housing. The retaining tangs radially constrain the pads.
1 . A thrust bearing for an electric submersible pump, comprising:
a mounting ring comprising spring elements;
pads each comprising a fluid interface surface and a pivot surface, wherein slots are formed between the pivot surface and the fluid interface surface, and wherein the spring elements engage the slots to secure the pads to the mounting ring; and
a housing comprising an axial surface interfacing with the pivot surfaces, and an inner circumferential surface radially constraining the pads, wherein the housing surrounds the mounting ring.
2 . The thrust bearing of claim 1 , wherein
adjacent pairs of the spring elements extend tangentially towards each other,
the mounting ring further comprises stops respectively abutting the pads, and
the stops are each disposed between adjacent pairs of the spring elements.
3 . The thrust bearing of claim 1 , wherein the fluid interface surface comprises a first edge feature disposed at a first end of each pad, a second edge feature disposed at a second end of each pad, and a flat surface extending from the first edge feature to the second edge feature.
4 . The thrust bearing of claim 3 , wherein the first edge feature and the second edge feature each comprise a concavely curved surface.
5 . The thrust bearing of claim 3 , wherein the first edge feature and the second edge feature each comprise a convexly curved surface.
6 . The thrust bearing of claim 3 , wherein the first edge feature and the second edge feature each comprise a chamfer.
7 . The thrust bearing of claim 1 , wherein
there are spaces between the pads,
each pad of the pads is configured to independently tilt about the pivot surface in a radial direction, and
the fluid interface surfaces are configured such that a fluid film is formed between the fluid interface surfaces and a thrust runner when there is relative motion between the fluid interface surfaces and the thrust runner.
8 . A method of assembling the thrust bearing of claim 1 , comprising:
fastening the spring elements to the slots;
positioning the pads such that the axial surface interfaces with the pivot surfaces and the housing surrounds the mounting ring;
positioning a first fixture against another axial surface of the housing;
bolting a second fixture to the first fixture to retain the pads, wherein the second fixture comprises a cylindrical plate and teeth extending radially outward from the cylindrical plate, wherein each of the teeth is disposed between two adjacent pads of the pads, and wherein each of the pads abuts an outer circumferential surface of the cylindrical plate;
lapping the fluid interface surfaces; and
removing the first fixture and the second fixture.
9 . A method of assembling an electric submersible pump, comprising:
interfacing the thrust bearing of claim 1 with a thrust runner affixed to a shaft connected to an electric motor of an electric motor assembly;
connecting the electric motor assembly to a seal unit; and
connecting the seal unit to a centrifugal pump.
10 . A method of lifting fluid in a wellbore comprising:
running an electric submersible pump comprising the thrust bearing of claim 1 into a wellbore; and
providing electric power to the electric submersible pump.
11 . A thrust bearing for an electric submersible pump, comprising:
mounting clips comprising spring elements and retaining tangs;
pads each comprising a fluid interface surface and a pivot surface, wherein slots are formed between the pivot surface and the fluid interface surface, and wherein the spring elements engage the slots to secure the pads to the mounting clips; and
a housing comprising an axial surface interfacing with the pivot surfaces, wherein the mounting clips are affixed to the housing, and wherein the retaining tangs radially constrain the pads.
12 . The thrust bearing of claim 11 , wherein
the spring elements of each mounting clip extend tangentially away from each other,
the retaining tangs of each mounting clip extend tangentially away from each other,
openings are respectively formed in the mounting clips, and
bolts respectively extend through the openings and into holes in the housing to fasten the mounting clips to the housing.
13 . The thrust bearing of claim 11 , wherein
the fluid interface surface comprises a first edge feature disposed at a first end of each pad,
a second edge feature disposed at a second end of each pad, and
a flat surface extending from the first edge feature to the second edge feature.
14 . The thrust bearing of claim 13 , wherein the first edge feature and the second edge feature each comprise a concavely curved surface.
15 . The thrust bearing of claim 13 , wherein the first edge feature and the second edge feature each comprise a convexly curved surface.
16 . The thrust bearing of claim 13 , wherein the first edge feature and the second edge feature each comprise a chamfer.
17 . The thrust bearing of claim 11 , wherein
there are spaces between the pads,
each pad of the pads is configured to independently tilt about the pivot surface of the pad in a radial direction, and
the fluid interface surfaces are configured such that a fluid film is formed between the fluid interface surfaces and a thrust runner when there is relative motion between the fluid interface surfaces and the thrust runner.
18 . A method of assembling the thrust bearing of claim 11 , comprising:
positioning the pads such that the axial surface interfaces with the pivot surfaces;
inserting the spring elements into the slots;
fastening the mounting clips to the housing, wherein the fastening of the mount clips to the housing causes deformation of the mounting clips that secures the spring elements inside the slots;
positioning a first fixture against another axial surface of the housing;
bolting a second fixture to the first fixture, wherein the second fixture comprises a cylindrical plate and teeth extending radially outward from the cylindrical plate, wherein each of the teeth is disposed between two adjacent pads of the pads, and wherein each of the pads abuts an outer circumferential surface of the cylindrical plate;
lapping the fluid interface surfaces; and
removing the first fixture and the second fixture.
19 . A method of assembling an electric submersible pump, comprising:
interfacing the thrust bearing of claim 11 with a thrust runner affixed to a shaft connected to an electric motor of an electric motor assembly;
connecting the electric motor assembly to a seal unit; and
connecting the seal unit to a centrifugal pump.
20 . A method of lifting fluid in a wellbore comprising:
running an electric submersible pump comprising the thrust bearing of claim 11 into a wellbore; and
providing electric power to the electric submersible pump.