US-12624705-B1 - Thrust bearing with tilting pad

Abstract

A thrust bearing for an electric submersible pump includes a housing including an axial surface and an inner circumferential surface. Holes and bores are formed in the axial surface. The thrust bearing further includes sockets respectively disposed in the holes and pads each including a fluid interface surface. Two open counterbores are formed in each of the pads. The inner circumferential surface radially constrains the pads. The thrust bearing further includes balls each engaging one of the sockets and one of the pads and retaining bolts each including a head and a shaft extending from the head. Each of the shafts is disposed in one of the bores. The thrust bearing further includes biasing members each disposed between a bearing surface of one of the heads and bottom surfaces of two of the open counterbores. The pads are able to pivot on the ball.

Inventors

• Michael RIMMER

Assignees

• HALLIBURTON ENERGY SERVICES, INC.

Dates

Publication Date

20260512

Application Date

20241114

Claims (20)

1. 1 . A thrust bearing for an electric submersible pump, comprising: a housing comprising an axial surface and an inner circumferential surface, wherein holes and bores are formed in the axial surface; sockets respectively disposed in the holes; pads each comprising a fluid interface surface, wherein two open counterbores are formed in each of the pads, and wherein the inner circumferential surface radially constrains the pads; balls each engaging one of the sockets and one of the pads; retaining bolts each comprising a head and a shaft extending from the head, wherein each of the shafts is disposed in one of the bores; and biasing members each disposed between a bearing surface of one of the heads and bottom surfaces of two of the open counterbores.
2. 2 . The thrust bearing of claim 1 , wherein the sockets each comprise an inner frustoconical surface, the pads each comprise an inner conical surface, and each of the balls engages one of the inner frustoconical surfaces and one of the inner conical surfaces.
3. 3 . The thrust bearing of claim 1 , wherein each of the pads is configured to tilt about the ball in a radial direction.
4. 4 . The thrust bearing of claim 1 , wherein each of the pads is configured to tilt about the ball in a tangential direction.
5. 5 . The thrust bearing of claim 1 , wherein there is clearance between the heads and the pads.
6. 6 . The thrust bearing of claim 1 , further comprising lock washers disposed between the housing and the retaining bolts.
7. 7 . The thrust bearing of claim 1 , further comprising shims disposed between the housing and the sockets, wherein the shims are configured to set positions of the faces of the pads.
8. 8 . The thrust bearing of claim 1 , wherein the fluid interface surface comprises a first edge feature disposed at a first end of the pad, a second edge feature disposed at a second end of the pad, and a flat surface extending from the first edge feature to the second edge feature.
9. 9 . The thrust bearing of claim 8 , wherein the first edge feature and the second edge feature each comprise a concavely curved surface.
10. 10 . The thrust bearing of claim 8 , wherein the first edge feature and the second edge feature each comprise a convexly curved surface.
11. 11 . The thrust bearing of claim 8 , wherein the first edge feature and the second edge feature each comprise a chamfer.
12. 12 . The thrust bearing of claim 8 , wherein each of the pads comprises a first chamfer proximate the first edge feature and a second chamfer proximate the second edge feature, and the open counterbores are formed in the first chamfers and the second chamfers.
13. 13 . The thrust bearing of claim 1 , wherein there are spaces between the pads.
14. 14 . The thrust bearing of claim 1 , wherein the biasing members bias the pads in an axial direction.
15. 15 . The thrust bearing of claim 1 , wherein 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.
16. 16 . The thrust bearing of claim 1 , wherein each of the pads is configured to tilt with the ball about the socket in a radial direction.
17. 17 . The thrust bearing of claim 1 , wherein each of the pads is configured to tilt with the ball about the socket in a tangential direction.
18. 18 . A method of assembling the thrust bearing of claim 1 , comprising: placing the sockets in the holes; placing the balls on the sockets; placing the pads on the balls; constraining the pads from moving using fixtures mounted between the pads, wherein the fixtures are bolted to the housing using mounting bolts that extend into the bores; lapping the fluid interface surfaces; removing the fixtures from the pads; placing the biasing members on the bottom surfaces of the open counterbores such that each of the biasing members contacts two of the bottom surfaces; and bolting the retaining bolts to the housing, wherein the shafts extend through the biasing members.
19. 19 . 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.
20. 20 . A method of lifting fluid in a wellbore, comprising: running the electric submersible pump assembled by the method of claim 19 into a wellbore; and providing electric power to the electric motor.

Description

BACKGROUND With high temperature of downhole motors of electric submersible pumps (ESPs), conventional materials such as steel, brass or polymers may become unsuitable for the operating environment at the bearing running/contacting faces. This may be because of material degradation at higher temperatures (e.g., materials start to corrode at an increased rate, the material starts to pit, and/or chemical reactions start to occur and/or the material physically melts). This may also be because of loss of strength (e.g., materials exhibit a rapid loss in mechanical properties, which results in low strengths and subsequent failure of the material). Ceramic materials may be more able to deal with these conditions as the materials are typically insensitive to high temperatures and to chemicals. However, ceramics may also present some manufacturing limitations as the materials are extremely hard, making processing difficult. This can limit the manufacturing methods available, and therefore some designs possible in metals and polymers may no longer be possible in ceramic. Ceramics also pose a secondary issue in that typically, their thermal expansion coefficients are much lower than metals and polymers. Some ceramic bearing solutions fuse bond a layer of ceramic to a metallic substrate and/or join the materials by mechanical means, such as an interference. However, temperature changes may result in thermally induced stresses at the interfaces that may result in cracks to the ceramic and eventual bearing failure. The systems and methods of the present disclosure may address one or more of these issues. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. FIG. 1 is a schematic diagram of an ESP, according to an embodiment of the present disclosure; FIG. 2 is a cross-sectional side view of a motor of an ESP, according to an embodiment; FIG. 3 is a cross-sectional side view of a thrust bearing in a motor, according to an embodiment; FIG. 4 is a cross-sectional side view of a thrust bearing in a motor, according another embodiment; FIG. 5 is a perspective view of a pad assembly of the thrust bearing, according to an embodiment; FIG. 6 is a perspective view of the pads and the mounting ring of the pad assembly, according to the embodiment of FIG. 5; FIG. 7 is a top view of the pads and the mounting ring of the pad assembly, according to the embodiment of FIG. 5; FIG. 8 is a top enlarged view of a pad and the mounting ring of the pad assembly, according to the embodiment of FIG. 5; FIG. 9 is a perspective view of the mounting ring of the pad assembly, according to the embodiment of FIG. 5; FIG. 10 is a perspective view of a pad of the pad assembly, according to the embodiment of FIG. 5; FIG. 11 is a perspective view of the pad assembly illustrating the insertion of the pad, according to the embodiment of FIG. 5; FIG. 12 is an exploded view of the thrust bearing and fixtures for assembling the pad assembly, according to an embodiment; FIG. 13 is a cutaway view of the thrust bearing and the fixtures for assembling the pad assembly, according to the embodiment of FIG. 12; FIG. 14 is a perspective view of a pad assembly of a thrust bearing, according to another embodiment; FIG. 15 is a perspective view of a mounting clip of the pad assembly, according to the embodiment of FIG. 14; FIG. 16 is a perspective cross-sectional view of the pad assembly of FIG. 14; FIG. 17 is a cutaway perspective view of the pad assembly of FIG. 14; FIG. 18 is a cross-sectional side view of the pad assembly of FIG. 14; FIG. 19 is a perspective view of a pad assembly, according to yet another embodiment; FIG. 20 is a perspective cross-sectional view of the pad assembly of FIG. 19; FIG. 21 is a perspective cross-sectional view of the pad assembly of FIG. 19; FIG. 22 is a perspective view of a housing of the pad assembly of FIG. 19; FIG. 23 is a perspective view of a socket of the pad assembly of FIG. 19; FIG. 24 is a side cross-sectional view of the socket of the pad assembly of FIG. 19; FIG. 25 is a perspective view of a pad of the pad assembly of FIG. 19; FIG. 26 is another perspective view of the pad of the pad assembly of FIG. 19; FIG. 27 is a perspective cross-sectional view of the pad of the pad assembly of FIG. 19; FIG. 28 is a perspective view of the thrust bearing and fixtures for lapping the pad assembly, according to another embodiment; FIG. 29 is a side cross-sectional view of the thrust bearing and fixtures for lapping the pad assembly, according to the embodiment of FIG. 28; FIG. 30 is a schematic diagram of the fluid interface surface of the pad, according to an embodiment; FIG. 31 is a schematic diagram of the fluid interface surface of the pad, according to another embodiment; FIG. 32 is a schematic diagram of