WO2024059646A1

WO2024059646A1 - Joints for progressive cavity devices

Info

Publication number: WO2024059646A1
Application number: PCT/US2023/074090
Authority: WO
Inventors: Clifton Dee Eggleston; Randall Ferrain Weaver
Original assignee: National Oilwell Varco, L.P.
Priority date: 2022-09-14
Filing date: 2023-09-13
Publication date: 2024-03-21
Also published as: WO2024059646A4

Abstract

A progressive cavity device includes a stator, a rotor positioned within the stator, a driveshaft, and a joint coupling the driveshaft and the rotor. The joint includes a pivotable member fixably coupled to and engaged with an end of the driveshaft. The pivotable member has a central axis, a first end proximal the driveshaft, a second end distal the driveshaft, and a radially outer surface extending axially from the first end of the pivotable member to the second end of the pivotable member. The joint also includes a first wear pad mounted on the pivotable member. In addition, the joint includes a torque key disposed about the pivotable member and positioned radially adjacent the radially outer surface of the pivotable member. The torque key is rotationally locked to the rotor.

Description

JOINTS FOR PROGRESSIVE CAVITY DEVICES

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. provisional patent application Serial No. 63/406,571 filed September 14, 2022 and entitled "Joints for Progressive Cavity Devices," which is hereby incorporated herein by reference in its entirety for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

BACKGROUND

[0003] Progressive cavity devices may be implemented as, for example, pumps or motors. When configured as a pump, a progressive cavity device is a type of positive displacement pump that pressurizes fluid through a series of cavities that are formed between a rotor and a stator. Progressive cavity pumps may be used to induce fluid flow in a number of different services and industries. For instance, progressive cavity pumps may be used to pump fluid within an industrial process (e.g., chemical plant, water treatment facility, refinery, etc.). When configured as a motor, a progressive cavity device is configured to force a pressurized fluid through the series of cavities formed between the rotor and stator to drive rotation of other components. In some implementations, progressive cavity motors may be utilized to drive rotation of a drill bit to therefore lengthen a subterranean wellbore (e.g., such as wellbores formed to access subterranean hydrocarbon resources). When used in this circumstance, the progressive cavity motor may be commonly referred to as a “mud motor” because the pressurized fluid forced through the progressive cavity motor may comprise a drilling mud or other drilling fluid.

BRIEF SUMMARY

[0004] Embodiments of progressive cavity devices are disclosed herein. In one embodiment, a progressive cavity device comprises a stator, a rotor positioned within the stator, a driveshaft, and a joint coupling the driveshaft and the rotor. The joint comprises a pivotable member fixably coupled to and engaged with an end of the driveshaft. The pivotable member has a central axis, a first end proximal the driveshaft, a second end distal the driveshaft, and a radially outer surface extending axially from the first end of the pivotable member to the second end of the pivotable member. The joint also comprises a first wear pad mounted on the pivotable member. In addition, the joint comprises a torque key disposed about the pivotable member and positioned radially adjacent the radially outer surface of the pivotable member. The torque key is rotationally locked to the rotor. The pivotable member and the torque key are configured to rotate together. The pivotable member is configured to pivot relative to the torque key. Further, the joint comprises a second wear pad mounted to the torque key. The second wear pad engages the first wear pad. Engagement of the first wear pad and the second wear pad is configured to transfer torque between the pivotable member and the torque key.

[0005] Embodiments of joints for coupling a rotor to a driveshaft within a progressive cavity device, the rotor being rotatable within a stator, are disclosed herein. In one embodiment, a joint for coupling a rotorto a driveshaft within a progressive cavity device comprises a pivotable member having a central axis, a first end, a second end opposite the first end, and a radially outer surface extending axially from the first end to the second end. The pivotable member includes a throughbore extending axially from the first end and the second end. The throughbore is configured to receive the driveshaft therein. The radially outer surface of the pivotable member includes a first convex spherical surface extending axially from the first end and a second convex spherical surface extending axially from the second end. In addition, the joint comprises a plurality of first wear pads disposed along the radially outer surface of the pivotable member axially between the first convex spherical surface and the second convex spherical surface. Further, the joint comprises a torque key having a first end, a second end opposite the first end of the torque key, and a radially inner surface extending axially from the first end of the torque key to the second end of the torque key. The torque key is disposed about the pivotable member with the radially inner surface of the torque key radially adjacent the radially outer surface of the pivotable member. Moreover, the joint comprises a plurality of second wear pads disposed along the radially inner surface of the torque key. Each second wear pad of the torque key engages a corresponding one of the first wear pads of the pivotable member with the radially inner surface of the torque key. The torque key is configured to be rotationally locked to the rotor. The pivotable member is configured to pivot omnidirectionally relative to the torque key.

[0006] Embodiments described herein comprise a combination of features and characteristics intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical characteristics of the disclosed embodiments in order that the detailed description that follows may be better understood. The various characteristics and features described above, as well as others, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes as the disclosed embodiments. It should also be realized that such equivalent constructions do not depart from the spirit and scope of the principles disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a detailed description of various embodiments, reference will now be made to the accompanying drawings in which:

[0008] FIG. 1 is a side, schematic cross-sectional view of an embodiment of a progressive cavity device in accordance with the principles described herein;

[0009] FIG. 2 is a partial, perspective, quarter cross-sectional view of the progressive cavity device of FIG. 1 ;

[0010] FIG. 3 is an exploded, perspective view of one of the joints of the progressive cavity device of FIG. 2;

[0011] FIG. 4 is a perspective view of the pivotable member of the joint of FIG. 3;

[0012] FIG. 5 is an end view of the pivotable member of FIG. 4;

[0013] FIG. 6 is a perspective view of torque keys of the joint of FIG. 3;

[0014] FIG. 7 is a perspective view of the inner annular cap of the joint of FIG. 3;

[0015] FIG. 8 is a perspective view of the outer annular cap of the joint of FIG. 3;

[0016] FIG. 9 is a cross-sectional side view of the joint of FIG. 3 engaged between the driveshaft and input shaft of the progressive cavity device of FIG. 2;

[0017] FIG. 10 is a cross-sectional view of the joint of FIG. 3 taken along section A-A in FIG. 9; [0018] FIG. 11 is a perspective, partial cross-sectional view of the joint of FIG. 9;

[0019] FIG. 12 is an exploded, perspective view of an embodiment of a joint for a progressive cavity device in accordance with the principles described herein;

[0020]

[0021] FIG. 13 is a perspective view of the pivotable member of the joint of FIG. 12;

[0022] FIG. 14 is an end view of the pivotable member of FIG. 13;

[0023] FIG. 15 is a perspective view of the inner annular cap of the joint of FIG. 12; [0024] FIG. 16 is a perspective view of the outer annular cap of the joint of FIG. 12;

[0025] FIG. 17 is a cross-sectional side view of the joint of FIG. 12 engaged between the driveshaft and input shaft of the progressive cavity device of FIG. 2;

[0026] FIG. 18 is a cross-sectional view of the joint of FIG. 3 taken along section B-B in FIG. 17; and

[0027] FIG. 19 is a perspective, partial cross-sectional view of the joint of FIG. 17.

DETAILED DESCRIPTION

[0028] As previously described, progressive cavity devices (which may be configured as a pump, motor, etc.) may advance fluid through a series of cavities that are formed between a rotor and a stator. The motion of the rotor within the stator may eccentric, or “precessional” in nature such the rotor (or portions thereof) may orbit about a central or longitudinal axis of the stator. In such a progressive cavity device, this eccentric motion of the rotor may be driven by (e.g., in the case of a progressive cavity pump) or may drive (e.g., in the case of a progressive cavity motor) a concentric rotation of another component (e.g., an input shaft, a drill bit, etc.). In the particular case of a progressive cavity pump, the eccentric rotation of the rotor may be driven by an input shaft that is concentrically rotated about its own central axis by a suitable driver (e.g., electric motor, hydraulic motor, internal combustion engine, etc.). Thus, suitable joints may be coupled between the eccentrically and concentrically rotating components of a progressive cavity device that are to convert the eccentric rotation of the rotor to concentric rotation (or vice versa). In some instances, these joints may be referred to as “universal joints,” because they facilitate omnidirectional pivoting of two components relative to one another while transferring torque therebetween.

[0029] The joints connecting the rotor to other rotating components of a progressive cavity device may include interlocking teeth, splines or other components that facilitate the transfer of torque therethrough. These components may be particularly vulnerable to wear and erosion if exposed to process fluids that are being flowed through the progressive cavity pump (e.g., the fluids that are flowed within the cavities formed between the rotor and stator). As a result, such joints are typically separated from the process fluid via one or more seals or barriers. However, these fluid seals and barriers often define the operational limits of a progressive cavity pump, particularly the operating pressure and temperature. Moreover, the failure of these seals or barriers may then lead to further damage to the progressive cavity device that may require repair or replacement thereof.

[0030] Accordingly, the embodiments disclosed herein include embodiments of joints for a progressive cavity device that are tolerant to the wear and erosive effects resulting from exposure to process fluids during operations. Thus, the joints of the embodiments disclosed herein may be implemented within a progressive cavity device (e.g., a progressive cavity pump or a progressive cavity motor) without additional seals or fluid barriers, thereby removing the above-mentioned limitations on the operational conditions of the pump. As a result, through use of the embodiments disclosed herein, a progressive cavity pump may be operated in more severe services (which may include higher temperatures and/or pressures), while enjoying a higher reliability.

[0031] Referring now to FIG. 1 , a progressive cavity device 10 is shown according to some embodiments. The particular progressive cavity device 10 of FIG. 1 is configured as a pump, and thus may be referred to herein as a “progressive cavity pump 10,” or more simply “pump 10.” However, it should be appreciated that the embodiments of the progressive cavity devices disclosed herein may be implemented as a progressive cavity motor (e.g., such as a mud motor used in a subterranean wellbore) or other progressive cavity devices.

[0032] Pump 10 generally includes a fluid end 20 and a drive end 40. During operations, process fluid may be flowed into fluid end 20 via an inlet 12 and is thereafter emitted at a higher pressure at an outlet 14 if fluid end 20.

[0033] Fluid end 20 includes a stator 22 and a rotor 30 positioned within the stator 22. The rotor 30 comprises a shaft formed with one or more helical vanes or lobes 32 extending along its length. The stator 22 defines helical lobes or vanes 24 that are complimentary to the rotor lobes 32. The helical lobes 24 of the stator 22 may extend helically about a central or longitudinal axis 25 of stator 22. [0034] During operations, the rotor 30 may rotate eccentrically within the stator 22 (e.g., in a processional manner as previously described above). Specifically, the rotor 30 may orbit about the longitudinal axis 25 within stator 22 so that lobes 32 on rotor engage with the lobes 24 of stator 22 so as to form cavities therebetween that progress axially along axis 25 of stator 22 toward outlet 14.

[0035] Referring still to FIG. 1 , the drive end 40 of pump 10 includes an input shaft 42 that is coupled to a driver 44. Input shaft 42 includes a central or longitudinal axis 45. Driver 44 may comprise any suitable motor or other driver (e.g., electric motor, hydraulic motor, internal combustion engine, etc.) that is configured to rotate the input shaft 42 about axis 45 during operations.

[0036] The rotor 30 is coupled to input shaft 42 through a driveshaft 50. In particular, the driveshaft 50 includes central or longitudinal axis 55, a first end 50a, and a second end 50b that is opposite first end 50a along axis 55. The first end 50a is coupled to the input shaft 42, and the second end 50b is coupled to the rotor 30a. Thus, during operations, the driveshaft transfers torque from the input shaft 42 to the rotor 30 and converts the concentric rotation of the input shaft 42 about axis 45 into the processional motion of the rotor 30 about axis 25 of stator 22. To accommodate the eccentric and concentric rotational motion of the rotor 30 and input shaft 42, respectively, the driveshaft 50 may be coupled to the input shaft 42 and rotor 30 via a pair of joints 100. As will be described in more detail below, the joints 100 allow omnidirectional pivoting of the first end 50a of driveshaft 50 relative to the input shaft 42 and of the second end 50b of driveshaft 50 relative to the rotor 30. Thus, the joints 100 may be referred to herein as “universal joints.” In addition, as will also be described below, the universal joints 100 may be formed so as to be resistant to wear, erosion, and other damage resulting from exposure to process fluids that flow between the rotor 30 and stator 22 between the inlet 12 and outlet 14.

[0037] FIG. 2 shows an enlarged quarter-cross-sectional view of an embodiment of progressive cavity pump 10 that further illustrates the universal joints 100. Features of the progressive cavity pump 10 shown in FIG. 2 are identified with the same reference numerals as those used for the corresponding features shown in FIG. 1 . As can be appreciated in FIG. 2, the components of joints 100 (e.g., pivotable members 110, torque keys 130, annular caps 150, 170, etc., each of which is described in more detail below) are exposed to process fluid that enters pump 10 via inlet 12. Further details of the joints 100 shown in FIG. 2 are described in more detail below according to some embodiments.

[0038] Referring now to FIG. 3, an exploded perspective view of one of joint 100 is shown, it being understood that both joints 100 within pump 10 (FIGS. 1 and 2) may be configured the same. Joint 100 includes a pivotable member 110 and a plurality of torque keys 130 captured axially between a pair of annular caps - namely a first or inner annual cap 170 and a second or outer annular cap 150 along a central axisl 05. As will be described in more detail below, during operations, one or more components of joint 100 (e.g., pivotable member 110) may be pivoted and misaligned with axis 105 during operation of pump 10.

[0039] In addition, as used herein, the terms “inner” and “outer” when used with respect to components (or ends thereof) of the joint 100 may refer to the relative position of this component (or end thereof) relative to an axial center or midpoint of driveshaft 50 (FIGS. 1 and 2). Thus, the inner annular cap 170 may be positioned closer to an axial midpoint of driveshaft 50 than the outer annular cap 150, when joint 100 is coupled to driveshaft 50 as shown in FIG. 2.

[0040] Referring now to FIGS. 4 and 5, pivotable member 110 includes a central axis 115, a first or inner end 110a, and a second or outer end 110b opposite inner end 110a. During operations the axis 115 of pivotable member 110 may be aligned with axis 55 of driveshaft 50 that that axis 115 may be misaligned and pivoted relative to the axis 105 of joint 100 (FIG. 3).

[0041] A throughbore 112 extends axially through the pivotable member 110, between the ends 1 10a, 110b along axis 115. As will be described in more detail below, throughbore 112 may include a plurality of teeth or splines 113 (shown in FIG. 5) that interlock or otherwise engage with corresponding features (e.g., teeth, splines, etc.) formed on an external surface of driveshaft 50 (FIG. 10).

[0042] Pivotable member 110 also includes a radially outer surface 110c that extends axially between the ends 110a, 110b along axis 115. The radially outer surface 110c includes a first or inner spherical surface 114, a cylindrical surface 116 extending axially from the inner spherical surface 114, and a second or outer spherical surface 118 extending axially from cylindrical surface 116 toward outer end 110b. The spherical surfaces 114, 118 comprise partial spherical segments that extends circumferentially about the axis 115. Thus, the spherical surfaces 114, 118 have a spherical convex curvature.

[0043] Referring still to FIGS. 4 and 5, a plurality of wear pads 126 are positioned on partial spherical surfaces 114, 118. In particular, a first set of the plurality of wear pads 126 are circumferentially spaced about axis 115 along inner spherical surface 114, and a second set of the plurality of wear pads 126 are circumferentially spaced about axis 115 along outer spherical surface 118. The wear pads 126 may comprise areas of durable material that are resistant to erosion and abrasion. In some embodiments, wear pads 126 comprise inserts that are embedded within spherical surfaces 114, 118. For instance, in some embodiments, wear pads 126 may be configured as inserted that are embedded within pockets or recesses formed in spherical surfaces 114, 118. The wear pads 126 may be welded, brazed, or otherwise secured within the pockets of spherical surfaces 1 14, 118 to prevent the wear pads 126 from disengaging from spherical surface 114, 118 during operations. In some embodiments, the wear pads 126 may be secured externally to the spherical surfaces 114, 118. In some embodiments, wear pads 126 may comprise polycrystalline diamond (PCD) or any other suitable durable material. For instance, in some embodiments, the wear pads 126 (or some of the wear pads 126) may be configured as coatings or treatments on the spherical surfaces 114, 118. Specifically, in some embodiments, the wear pads 126 (or some of the wear pads 126) may comprise surface coatings or treatments such as carbon coatings (e.g., carburizing), boron coatings (e.g., boronizing), ceramic coatings, etc. In some embodiments, the outer surface of the wear pads 126 may be flush with, raised above, or recessed into the corresponding spherical surface 114, 118. For instance, in some embodiments, the outer surface of wear pads 126 may be raised above the corresponding spherical surface 114, 118 to allow fluid to flow around the wear pads 126 and lubricate movement within the joint 100 during operations. In addition, in some embodiments, the outer surface of wear pads 126 (e.g., the surface of wear pads 126 that is most radially distal from the corresponding spherical surface 114, 118) may have a convex curvature, such as a convex curvature that corresponds with a curvature of the spherical surfaces 114, 118. For instance, in some embodiments, the outer surface of wear pads 126 may have a spherical convex curvature; however, other convex curvatures are contemplated in various embodiments. [0044] A plurality of lugs 120 extend radially outward from cylindrical surface 116 with respect to axis 115. In particular, in some embodiments, a pair of lugs 120 that are positioned on radially opposite sides of the pivotable member 110 about axis 115 (e.g., spaced approximately 180° apart from one another about axis 115). Each lug 120 extends circumferentially along cylindrical surface 116 between a pair of planar end surfaces 121 that are circumferentially spaced from one another about axis 115. A circumferential gap 123 may be defined circumferentially between each circumferentially adjacent pair of lugs 120 (particularly between the planar end surfaces 121 of each circumferentially adjacent pair of lugs 120). Thus, in the embodiment of pivotable member 110 shown in FIG. 4, in which two lugs 120 are included, there is a pair of circumferential gaps 123 that are positioned circumferentially between the lugs 120 and positioned on radially opposite sides of the pivotable member 110 about axis 115 (e.g., spaced approximately 180° apart from one another about axis 115).

[0045] A wear pad 124 may be formed on each of the planar end surfaces 121 of each lug 120. The wear pads 124 may be similar to the wear pads 126 positioned on spherical surfaces 114, 118. Thus, in some embodiments, the wear pads 124 may comprise inserts that are embedded within the planar end surfaces 121. In some embodiments, the wear pads 124 may be externally engaged with (as compared to embedded within) the planar end surfaces 121. As previously described for the wear pads 126, in some embodiments the wear pads 124 may comprise PCD or any other suitable durable material (e.g., such as a surface treatment or coating as previously described). In some embodiments, the outer surface of each wear pad 124 (that is, the most distal surface of wear pad 124 from the corresponding planar end surface 121 may have a convex curvature. For instance, in some embodiments the outer surface of each wear pad 124 may have a spherical convex curvature. In some embodiments, the outer surface of each wear pad 124 may have a non-spherical convex curvature, such as for instance, a cylindrical curvature whereby the outer surface of the wear pad 124 is positioned within and extends along a cylindrical plane having an axis of curvature that extends substantially perpendicular to a normal axis extending from planar end surface 121 . Without being limited to this or any other theory, a cylindrical outer surface of wear pad 124 may promote line contact between wear pads 124 and wear pads 134 on torque keys 130 (described in more detail below). Line contact may be more desirable for distributing forces and pressures between contacting surfaces over other, smaller contact areas (e.g., point contact), while still allowing relative pivoting between the wear pads 124, 134.

[0046] Referring now to FIGS. 3 and 6, the torque keys 130 comprise arcuate members that are circumferentially arranged about axis 105. More particularly, and as best shown in FIG. 6, each torque key 130 includes a first or inner end 130a and a second or outer end 130b axially opposite inner end 130a with respect to axis 105. In addition, each torque key 130 includes a radially outer arcuate surface 130c and a radially inner arcuate surface 130d that is positioned radially closer to axis 105 than radially outer arcuate surface 130c when torque keys 130 are installed within pump 10 as shown in FIG. 2. In some embodiments, the radially outer arcuate surface 130c and the radially inner arcuate surface 130d may be cylindrical surfaces having a common center of curvature. The center of curvature of the radially outer arcuate surface 130c and the radially inner arcuate surface 130d may be generally positioned on the axis 105 when torque keys 130 are installed within joint 100 as shown.

[0047] Referring still to FIG. 6, each torque key 130 includes a pair of planar end surfaces 132 that are circumferentially spaced from one another about axis 105. Each of the planar end surfaces 132 may extend radially away from axis 105, between the radially inner arcuate surface 130d and the radially outer arcuate surface 130c.

[0048] A pair of axially extending projections (or lugs) 136 extend axially away from inner end 130a and outer end 130b. In some embodiments, each projection 136 may be positioned radially closer to the radially outer arcuate surface 130c than the radially inner arcuate surface 130d. For instance, in some embodiments, a radially outermost surface 137 of each projection 136 (with respect to axis 105) may be flush (or co-planar) within the radially outer arcuate surface 130c. Thus, the radially outermost surface 137 may be a cylindrical surface.

[0049] Referring still to FIG. 6, each planar end surface 132 of torque keys 130 includes a wear pad 134. The wear pads 134 may be similar to the wear pads 124, 126 of pivotable member 110. Thus, in some embodiments, the wear pads 134 may comprise inserts that are inserted or embedded within the planar end surfaces 132. In some embodiments, the wear pads 134 may be externally engaged with (as compared to embedded within) the planar end surfaces 132. As previously described for the wear pads 124, 126, in some embodiments the wear pads 134 may comprise PCD or any other suitable abrasion resistant material. In some embodiments, the outer surface of each wear pad 134 (that is, the most distal surface of wear pad 134 from the corresponding planar end surface 132 may have a convex curvature. For instance, in some embodiments the outer surface of each wear pad 134 may be flat or planar. As previously described, the outer surface of wear pads 124 on lugs 120 may have a convex curvature (e.g., a convex spherical curvature, convex cylindrical curvature, etc.). Thus, as is described in more detail below, engagement between the convexly curved wear pads 124 and the planar wear pads 134 (e.g., point contact, line contact, etc.) may allow relative pivoting between the pivotable member 110 and torque keys 130 as torque is transferred therebetween during operations.

[0050] Referring now to FIGS. 3 and 7, inner annular cap 170 is a generally annularly shaped member having a first or inner end 170a, a second or outer end 170b opposite inner end 170a, and a circumferential outer surface 170c extending axially between ends 170a, 170b and circumferentially about axis 105. A recess 174 extends axially into inner annular cap 170 from outer end 170b, and a port or aperture 176 extends axially from recess 174 to inner end 170a.

[0051] A plurality of recesses (or notches) 172 extend radially into circumferential outer surface 170c. The recesses 172 may be uniformly circumferentially spaced about axis 105. Specifically, in some embodiments, inner annular cap 170 includes two recesses 172 that are circumferentially spaced approximately 180° apart from one another about axis 105.

[0052] Recess 174 includes (or defines) a concave spherical surface 178 extending circumferentially about axis 105. The spherical surface 178 may include a plurality of wear pads 180. The wear pads 180 may be similar to the wear pads 124, 126 of pivotable member 110. Thus, in some embodiments, the wear pads 180 may comprise inserts that are inserted or embedded within the concave spherical surface 178. In some embodiments, the wear pads 180 may be externally engaged with (as compared to embedded within) concave spherical surface 178. As previously described for the wear pads 124, 126, in some embodiments the wear pads 180 may comprise PCD or any other suitable durable material. In some embodiments, the outer surface of each wear pad 180 (that is, the most distal surface of wear pad 180 from the concave spherical surface 178) may have a convex curvature, or may be flat or planar. In some embodiments, the outer surface of wear pads 180 may be flat so that the contact with the convexly curved wear pads 126 on spherical surface 114 of pivotable member 110 (which may comprise point contact or line contact) may allow relative pivoting between the pivotable member 110 and inner annular cap 170 during operations.

[0053] Referring now to FIGS. 3 and 8, outer annular cap 150 is a generally annularly shaped member having a first or inner end 150a, a second or outer end 150b opposite inner end 150a, and a radially outer surface 150c extending axially between ends 150a, 150b and circumferentially about axis 105. A recess 154 extends axially into inner annular cap 150 from inner end 150a, and a port or aperture 160 extends axially from recess 154 to outer end 150b. In addition, a recess (or notch) 152 extends radially into radially outer surface 150c.

[0054] Recess 154 includes (or defines) a concave spherical surface 156 extending circumferentially about axis 105. The spherical surface 156 may include a plurality of wear pads 158. The wear pads 158 may be similar to the wear pads 124, 126 of pivotable member 110. Thus, in some embodiments, the wear pads 158 may comprise inserts that are inserted or embedded within the concave spherical surface 156. In some embodiments, the wear pads 158 may be externally engaged with (as compared to embedded within) concave spherical surface 156. As previously described for the wear pads 124, 126, in some embodiments the wear pads 158 may comprise PCD or any other suitable abrasion resistant material. In some embodiments, the outer surface of each wear pad 158 (that is, the most distal surface of wear pad 158 from the concave spherical surface 156 may have a convex curvature, or may be flat or planar. In some embodiments, the outer surface of wear pads 158 may be flat so that the contact with the convexly curved wear pads 126 on spherical surface 118 of pivoting member 110 (which may comprise point contact or line contact) may allow relative pivoting between the pivotable member 110 and outer annular cap 150 during operations.

[0055] Referring now to FIGS. 3 and 9-11 , during assembly of each joint 100, the pivotable member 110 and torque keys 130 are axially captured between the inner annular cap 170 and outer annular cap 150 along axis 105 and inserted within a receptacle 190. Receptacle 190 is an annular member that may be secured (e.g., via threads, welding, coupling, etc.) to either rotor 30 or input shaft 42 (depending on whether the joint 100 is to be coupled to the first end 50a or second end 50b, respectively, of driveshaft 50). In some embodiments, the receptacle 190 may be integrally formed on either the rotor 30 or input shaft 42. [0056] Receptacle 190 includes a circumferential or annular wall 196 that defines a recess or cavity 192. An annular shoulder 198 is defined within the cavity 192 that extends radially inward from annular wall 196 toward axis 105. A port or aperture 199 extends into annular shoulder 198. In addition, a plurality of recesses or notches 194 extend axially into annular wall 196. In some embodiments, the recesses 194 are uniformly circumferentially spaced about axis 105 along annular wall 196. For instance, in some embodiments, the receptacle 190 includes two recesses 194 spaced approximately 180° apart about axis 105.

[0057] The torque keys 130 are inserted into the circumferential gaps 123 between the lugs 120 of the pivotable member 110 such that the wear pads 124 on lugs 120 are engaged with the wear pads 134 on torque keys 130. In addition, the outer end 110b is inserted within the recess 154 of outer annular cap 150 so that the wear pads 126 on convex spherical surface 118 are engaged with wear pads 158 on concave spherical surface 156 within recess 154. As a result, the convex spherical surface 118 is spaced from the concave spherical surface 156 such that the surfaces 118, 156 are not in contact during operations. Further, the inner end 110a of pivotable member 110 is inserted within recess 174 of inner annular cap 170 so that the wear pads 126 on convex spherical surface 114 are engaged with wear pads 180 on concave spherical surface 178 within recess 174. As a result, the convex spherical surface 114 is spaced from the concave spherical surface 178 such that the surfaces 114, 178 are not in contact during operations. Without being limited to this or any other theory, because the surfaces 118, 156 and surfaces 114, 178 are spaced (or offset) from one another (and therefore not in contact with one another) via the contact between the wear pads 126, 158 and wear pads 126, 180, process fluid within the pump 10 (FIG. 2) may be allowed to flow freely between the surfaces 118, 156 and surfaces 114, 178 to cool and lubricate the joints 100 during operations.

[0058] Moreover, when the inner end 110a of pivotable member 110 is inserted within recess 174 of inner annular cap 170, the projections 136 on inner ends 130a of torque keys 130 may be inserted within recesses 172 on inner annular cap 170. As a result, the pivotable member 110, torque keys 130, and inner annular cap 170 are rotationally (and torsionally) locked via the engagement between the wear pads 132, 124, and between the projections 136 on inner end 130a of torque keys 130 and recesses 172 in inner annular cap 170. Thus, a rotation of the pivotable member 110 about axis 105 may result in a corresponding rotation of torque keys 130 and inner annular cap 170 during operations.

[0059] In addition, the pivotable member 110, torque keys 130, and outer annular cap 150 are inserted axially within recess 192 of receptacle 190 such that outer end 150b of outer annular cap 150 is engaged or abutted with annular shoulder 198. In addition, the projections 136 on outer end 130b of torque keys 130 are inserted within the recesses 194 on annular wall 196, and a pin 197 (e.g., a roll pin in some embodiments) is inserted through the aperture 199 in annular shoulder 198 and recess 152 in outer annular cap 150. Thus, the pivotable member 110, torque keys 130, outer annular cap 170, and receptacle 190 (and thus also input shaft 42 or rotor 30 depending on which joint 100 of FIG. 2 is being considered) are rotationally (and torsionally) locked to one another via the engagement between the wear pads 132, 124, the engagement between the projections 136 on outer ends 130a of torque keys 130 and recesses 194 in inner annular wall 196, and the pin 197 inserted within recess 154 and aperture 199. Thus, a rotation of the pivotable member 110 about axis 105 may result in a corresponding rotation of torque keys 130, outer annular cap 150, and receptacle 190 during operations.

[0060] Referring now to FIGS. 9-11 , within each joint 100, the ends 50a, 50b of driveshaft 50 are inserted through the aperture 178 and recess 174 of inner annular cap 170, throughbore 112 of pivotable member 110, and the recess 154 and aperture 160 of outer annular cap 150. FIGS. 9 and 10 illustrate the first end 50a of driveshaft 50 inserted within the joint 100 coupled to input shaft 42; however, the assembly of second end 50a of driveshaft and joint 100 coupled to rotor 30 may be configured in a similar manner as previously described.

[0061] Splines or teeth 52 may be formed on the outer surface of driveshaft 50 proximate to the end 50a (and also the second end 50b). The splines 52 may engage and interlock with the splines 113 formed within throughbore 112 of pivotable member 110, so as to generally align axis 115 of pivotable member 110 with the axis 55 of driveshaft 50 as previously described. A locking nut 54 may be threaded onto driveshaft 50 from the first end 50a (and the second end 50b for the universal joint 100 coupled to the rotor 30) so as to axially (with respect to axes 55, 115) compress the pivotable member 110 onto a radially extending annular shoulder 53 formed on driveshaft 50. [0062] Referring now to FIGS. 1 , 2, and 9-11 , the interlocking splines 52, 112 of driveshaft 50 and pivotable member 110 rotationally (and torsionally) lock the driveshaft 50 to the pivotable member 110. In the manner previously described, the pivotable member 110 is, in turn, rotationally (and torsionally) locked with receptacle 190 (which is further coupled to rotationally locked to input shaft 42 or rotor 30 as previously described). Thus, torque is transferred between the driveshaft 50 and receptacle 190 via each of the joints 100 so that a rotation of the input shaft 42 drives a rotation of the rotor 30 within stator 22 as previously described above.

[0063] In addition, the joints 100 coupled to ends 50a, 50b of driveshaft 50 allow for omnidirectional pivoting of the ends 50a and 50b relative to rotor 30 and input shaft 42, respectively. Specifically, the pivotable member 110 is configured to pivot omnidirectionally relative to torque keys 130 and annular caps 150, 170 due to the limited engagement between these components at wear pads 180, 126; 124, 134; 126, 158. Moreover, because engagement between the pivotable member 110, torque keys 130, and annular caps 150, 170 is largely limited to wear pads 180, 126; 124, 134; 126, 158, which are formed of durable materials as previously described, the wear and damage to universal joints 100 during operations is reduced. Further, because torque transfer within the universal joints 100 occurs at the engaged wear pads 180, 126; 124, 134; 126, 158, which again are formed from durable materials as previously described, the exposure of the universal joint 100 (including the internal components thereof) to process fluids flowing between rotor 30 and stator 22 is less likely to result in wear and damage within the joint 100 that may prevent the transfer of torque therethrough. Accordingly, additional seals and fluid barriers within progressive cavity pump 10 to prevent process fluid from entering joints 100 may be omitted, and pump 10 may provide increased reliability.

[0064] In the embodiment of joint 100 previously described, during rotation in a particular direction about axis 105, a significant portion of the torque loads (and associated wear) between each pivotable member 110 and corresponding torque keys 130 is borne by two of the four pairs of engaged wear pads 124, 134. To further enhance wear resistance, additional pairs of engaged wear pads (e.g., wear pads 124, 134) may be provided to transfer torque loads between the pivotable member and torque key(s) (e.g., pivotable member 110 and corresponding torque keys 130). An exemplary embodiment of a joint including additional pairs of engaged wear pads for transferring torque loads will now be described with reference to Figures For example, referring now to Figure 12-19.

[0065] Referring now to FIG. 12, an exploded perspective view of an embodiment of a joint 200 that can be used in place of one or both joints 100 within pump 10 previously described is shown. Joint 200 is similar to joint 100 previously described. Accordingly, for purposes of clarity and conciseness, the same reference numerals for the same features in both joints 100, 200 may be used and descriptions of such common features may be omitted with the understanding such features are the same or substantially the same in structure and function.

[0066] In this embodiment, joint 200 includes a pivotable member 210 and a plurality of torque keys 230 captured axially between a pair of annular caps - namely a first or inner annual cap 270 and a second or outer annular cap 150 along a central axis 205. As will be described in more detail below, during operations, one or more components of joint 200 (e.g., pivotable member 210) may be pivoted and misaligned with axis 205 during operation of the associated pump (e.g., pump 10).

[0067] Referring now to FIGS. 13 and 14, pivotable member 210 includes a central axis 215, a first or inner end 210a, and a second or outer end 210b opposite inner end 210a. During operations the axis 215 of pivotable member 210 may be aligned with axis 55 of driveshaft 50 such that axis 215 may be misaligned and pivoted relative to the axis 205 of joint 200 (FIG. 12).

[0068] A throughbore 212 extends axially through the pivotable member 210, between the ends 210a, 210b along axis 215. As will be described in more detail below, throughbore 212 may include a plurality of teeth or splines 213 that interlock or otherwise engage with corresponding features (e.g., teeth, splines, etc.) formed on an external surface of driveshaft 50 (FIGS. 17 and 18).

[0069] Pivotable member 210 also includes a radially outer surface 210c that extends axially between the ends 210a, 210b along axis 215. The radially outer surface 210c includes a first or inner spherical surface 214, a plurality of pairs of circumferentially- spaced inclined surfaces 216a, 216b extending axially from the inner spherical surface 214, and a second or outer spherical surface 218 extending axially from inclined surfaces 216a, 216b toward outer end 210b. The spherical surfaces 214, 218 are the same as spherical surfaces 114, 118 previously described, and thus, have a spherical convex curvature. In addition, wear pads 126 as previously described are uniformly circumferentially-spaced on spherical surfaces 214, 218. In addition, in this embodiment, a plurality of circumferentially-spaced holes or bores 217 extend axially through pivotable member 210 from spherical surface 214 to spherical surface 218. Bores 217 and wear pads 126 are arranged in an alternating fashion such that one bore 217 is circumferentially positioned between eaceh pair of circumferentially adjacent wear pads 126. Bores 217 allow fluid to flow through pivotable member 210 and lubricate movement within joint 200 during operations.

[0070] Referring still to FIGS. 13 and 14, each pair of inclined surfaces 216a, 216b extends axially from spherical surface 214 to spherical surface 218. In particular, each inclined surface 216a extends axially from inner spherical surface 214 to the corresponding inclined surface 216b, and each inclined surface 216b extends from the corresponding inclined surface 216a to outer spherical surface 218. Accordingly, each inclined surface 216a may also be referred to herein as a first or inner inclined surface 216a, and each inclined surface 216b may also be referred to herein as a second or outer inclined surface 216b.

[0071] Each surface 216a, 216b is a planar surface that slopes radially outwardly moving from axially from the corresponding spherical surface 214, 218, respectively, to the other surface 216a, 216b. Each pair of surfaces 216a, 216b intersect along a linear edge 216c positioned at the axial center of pivotable member 210. More specifically, each linear edge 216c is disposed in a plane oriented perpendicular to axis 215 and disposed at the axial center of pivotable member210. In this embodiment, each surface 216a, 216b is oriented at the same slope angle that ranges from 1 ° to 5° relative to axis 215, and alternatively, is 3°. Inclined surfaces 216a, 216b provide clearance between pivotable member 210 and torque keys 230 as pivotable member 210 pivots with driveshaft 50 relative to torque keys 230 and axis 205 of joint 200.

[0072] In this embodiment, four pairs of uniformly circumferentially-spaced inclined surfaces 216a, 216b are provided. Thus, each pair of circumferentially adjacent inclined surfaces 216a, 216b are angularly spaced 90° apart about axis 215. Consequently, as best shown in FIG. 14, inclined surfaces 216a, 216b generally define a square outer profile in end view. In other embodiments, a different number of pairs of circumferentially-spaced inclined surfaces (e.g., inclined surfaces 216a, 216b) are provided (e.g., six pair of inclined surfaces, etc.). [0073] A plurality of wear pads 124 as previously described are provided on each pair of inclined surfaces 216a, 216b. More specifically, in this embodiment, two wear pads 124 are provided on each pair of inclined surfaces 216a, 216b with one wear pad 124 being positioned at or proximal each lateral end of the corresponding pair of inclined surfaces 216a, 216b. In addition, each wear pad 124 is axially centered along linear edge 216c between the pair of corresponding inclined surfaces 216a, 216b. In this embodiment, the radially outermost surface of each wear pad 124 (that is, the surface of wear pad 124 facing radially outward away from axis 205) has a spherical convex curvature.

[0074] Referring again to FIG. 12, torque keys 230 comprise arcuate members that are circumferentially arranged about axis 205. More particularly, each torque key 230 includes a first or inner end 230a and a second or outer end 230b axially opposite inner end 230a with respect to axis 205. In addition, each torque key 230 includes a radially outer surface 230c and a radially inner surface 230d that is positioned radially closer to axis 205 than radially outer surface 230c. In this embodiment, the radially outer surface 230c of each torque key 230 is a cylindrical surface 231 and the radially inner surface 230d of each torque key 230 comprises a pair of planar surfaces 232. Cylindrical surfaces 231 of torque keys 230 have centers of curvature on axis 205 when torque keys 230 are installed within joint 200. Planar surfaces 232 are oriented parallel to axis 205 and oriented at an angle of 90° relative to each other about axis 205.

[0075] Each torque key 230 includes a pair of planar end surfaces 233 that are circumferentially spaced from one another about axis 205. Each of the planar end surfaces 233 extends radially away from axis 205 from radially inner surface 230d to radially outer surface 230c. When torque keys 230 are installed within joint 200 about pivotable member 210, planar end surfaces 233 of one torque key 230 abut and engage planar end surfaces 233 of the other torque key 230.

[0076] A pair of axially extending projections (or lugs) 237 extend axially away from each end 230a, 230b of each torque key 230. In this embodiment, projections 237 are circumferentially-centered on the corresponding torque key 230 such that each projection 237 is uniformly circumferentially spaced from each end surface 233 of the corresponding torque key 230. In some embodiments, each projection 237 may be positioned radially closer to the radially outer surface 230c than the radially inner surface 230d. For instance, in some embodiments, a radially outermost surface 238 of each projection 236 (with respect to axis 205) may be flush (or co-planar) within the radially outer surface 230c. Thus, the radially outermost surface 238 may be a cylindrical surface.

[0077] A plurality of holes or bores 236a extend axially through each torque key 230 from inner end 230a to outer end 230b, and one hole or bore 236b extends radially from each bore 236a to a corresponding one of the planar surfaces 232 of radially inner surface 230d. Bores 236a allow fluid to flow through each torque key 230 and lubricate movement within joint 200 during operations, and bores 236b allows fluid to flow to radially inner surface of torque keys 230 to lubricate relative movement between pivotable member 210 and torque keys 230 during operations.

[0078] Referring still to FIG. 12, each planar surface 232 includes a pair of circumferentially-spaced wear pads 134 as previously described. Wear pads 134 of torque keys 230 are radially aligned with and engage corresponding wear pads 124 of pivotable member 210. In addition, the radially inner end of each bore 236a along the corresponding planar surface 232 is circumferentially positioned between the pair of wear pads 134 on the same planar surface 232, thereby allowing the lubricating fluid delivered to each planar surface 232 to flow to both wear pads 134 on the same planar surface 232. In this embodiment, the radially innermost surface of each wear pad 134 (that is, the surface of wear pad 134 facing radially inward toward axis 205) is flat or planar. As previously described, the outer surface of each wear pad 124 on pivotable member 210 has a convex spherical curvature. Thus, as is described in more detail below, engagement between the convexly curved wear pads 124 and the planar wear pads 134 (e.g., point contact) allows relative pivoting between pivotable member 210 and torque keys 230 as torque is transferred therebetween during operations.

[0079] Referring now to FIGS. 12 and 15, inner annular cap 270 is the same as inner annular cap 170 previously described with the exception that inner annular cap 270 includes a plurality of uniformly circumferentially-spaced holes or bores 271 extending axially therethrough from inner end 170a to outer end 170b. Bores 281 allow fluid to flow through inner annular cap 270 and lubricate movement within joint 200 during operations. As best shown in FIGS. 12 and 16, outer annular cap 150 is as previously described.

[0080] [0081] Referring now to FIGS. 12 and 17-19, during assembly of each joint 200, the pivotable member 210 and torque keys 230 are axially captured between the inner annular cap 270 and outer annular cap 150 along axis 205 and inserted within a receptacle 190 as previously described. As described above, receptacle 190 may be secured (e.g., via threads, welding, coupling, etc.) to either a rotor 30 or an input shaft 42 (depending on whether the joint 200 is to be coupled to the first end 50a or second end 50b, respectively, of driveshaft 50).

[0082] Torque keys 230 are disposed about pivotable member 210 with each planar surface 232 radially adjacent and facing a corresponding pair of inclined surfaces 216a, 216b such that each wear pad 124 of pivotable member 210 is engaged with a corresponding wear pad 134 on torque keys 230. As a result, planar surfaces 232 are radially spaced from inclined surfaces 216a, 216b such that planar surfaces 232 are not in contact with inclined surfaces 216a, 216b during operations. In addition, the outer end 210b is inserted within the recess 154 of outer annular cap 150 so that the wear pads 126 on convex spherical surface 218 are engaged with wear pads 158 on concave spherical surface 156 within recess 154. As a result, the convex spherical surface 218 is spaced from the concave spherical surface 156 such that the surfaces 218, 156 are not in contact during operations. Further, the inner end 210a of pivotable member 210 is inserted within recess 174 of inner annular cap 270 so that the wear pads 126 on convex spherical surface 214 are engaged with wear pads 180 on concave spherical surface 178 within recess 174. As a result, the convex spherical surface 214 is spaced from the concave spherical surface 178 such that the surfaces 214, 178 are not in contact during operations. As surfaces 218, 156 and surfaces 214, 178 are spaced (or offset) from one another (and therefore not in contact with one another) via the contact between the wear pads 126, 158 and wear pads 126, 180, process fluid within the pump 10 (FIG. 2) may be allowed to flow freely between the surfaces 218, 156 and surfaces 214, 178 to cool and lubricate the joints 200 during operations. Still further, as planar surfaces 232 are spaced from inclined surfaces 216a, 216b, process fluid within the pump 10 (FIG. 2) may be allowed to flow freely between the surfaces 232 and surfaces 216a, 216b to cool and lubricate the joints 200 during operations. It should also be appreciated that bores 217, 236a, 236b, 271 allowed process fluid to flow freely through joints 200 and between opposed surfaces during operations. [0083] Moreover, when the inner end 210a of pivotable member 210 is inserted within recess 174 of inner annular cap 270, the projections 237 on inner ends 230a of torque keys 230 may be inserted within recesses 172 on inner annular cap 270. As a result, the pivotable member 210, torque keys 230, and inner annular cap 270 are rotationally (and torsionally) locked via the engagement between the wear pads 132, 124, and between the projections 237 on inner end 230a of torque keys 230 and recesses 172 in inner annular cap 270. Thus, a rotation of the pivotable member 210 about axis 205 may result in a corresponding rotation of torque keys 230 and inner annular cap 270 during operations.

[0084] Pivotable member 210, torque keys 230, and outer annular cap 150 are inserted axially within recess 192 of receptacle 190 such that outer end 150b of outer annular cap 150 is engaged or abutted with annular shoulder 198. Projections 237 on outer end 230b of torque keys 230 are inserted within the recesses 194 on annular wall 196, and a pin 197 as previously described is inserted through the aperture 199 in annular shoulder 198 and recess 152 in outer annular cap 150. Thus, the pivotable member 210, torque keys 230, outer annular cap 270, and receptacle 190 (and thus also input shaft 42 or rotor 30) are rotationally (and torsionally) locked to one another via the engagement between the wear pads 132, 124, the engagement between the projections 237 on outer ends 230a of torque keys 230 and recesses 194 in inner annular wall 196, and the pin 197 inserted within recess 154 and aperture 199. Thus, a rotation of the pivotable member 210 about axis 205 may result in a corresponding rotation of torque keys 230, outer annular cap 150, and receptacle 190 during operations.

[0085] Although this embodiment of joint 200 includes two torque keys 230, in other embodiments, more than two torque keys can be circumferentially arranged adjacent to each other about pivotable member 210. In addition, in some embodiments, the two torque keys 230 are formed as a single piece (rather than two pieces) with sufficient clearance to allow pivotable member 21 O to be positioned between planar surfaces 232. [0086] Referring now to FIGS. 17-19, within each joint 200, the ends 50a, 50b of driveshaft 50 are inserted through the aperture 178 and recess 174 of inner annular cap 270, throughbore 212 of pivotable member 210, and the recess 154 and aperture 160 of outer annular cap 150. FIGS. 17 and 18 illustrate the first end 50a of driveshaft 50 inserted within the joint 200 coupled to input shaft 42; however, the assembly of second end 50a of driveshaft and joint 200 coupled to rotor 30 may be configured in a similar manner as previously described.

[0087] Splines 52 of driveshaft 50 may engage and interlock with the splines 213 formed within throughbore 212 of pivotable member 210, so as to generally align axis 215 of pivotable member 210 with the axis 55 of driveshaft 50 as previously described. A locking nut 54 may be threaded onto driveshaft 50 from the first end 50a (and the second end 50b for the universal joint 100 coupled to the rotor 30) so as to axially (with respect to axes 55, 115) compress the pivotable member 210 onto a radially extending annular shoulder 53 formed on driveshaft 50.

[0088] Referring still to FIGS. 17-19, the interlocking splines 52, 212 of driveshaft 50 and pivotable member 210 rotationally (and torsionally) lock the driveshaft 50 to the pivotable member 210. In the manner previously described, the pivotable member 210 is, in turn, rotationally (and torsionally) locked with receptacle 190 (which is further coupled to rotationally locked to input shaft 42 or rotor 30 as previously described). Thus, torque is transferred between the driveshaft 50 and receptacle 190 via each of the joints 200 so that a rotation of the input shaft 42 drives a rotation of the rotor 30 within stator 22 as previously described above.

[0089] In addition, the joints 200 coupled to ends 50a, 50b of driveshaft 50 allow for omnidirectional pivoting of the ends 50a and 50b relative to rotor 30 and input shaft 42, respectively. Specifically, the pivotable member 210 is configured to pivot omnidirectionally relative to torque keys 230 and annular caps 150, 270 due to the limited engagement between these components at wear pads 180, 126; 124, 134; 126, 158. Moreover, because engagement between the pivotable member 210, torque keys 230, and annular caps 150, 270 is largely limited to wear pads 180, 126; 124, 134; 126, 158, which are formed of durable materials as previously described, the wear and damage to universal joints 200 during operations is reduced. Further, because torque transfer within the universal joints 200 occurs at the engaged wear pads 180, 126; 124, 134; 126, 158, which again are formed from durable materials as previously described, the exposure of the universal joint 200 (including the internal components thereof) to process fluids flowing between rotor 30 and stator 22 is less likely to result in wear and damage within the joint 200 that may prevent the transfer of torque therethrough. Accordingly, additional seals and fluid barriers within progressive cavity pump 10 to prevent process fluid from entering joints 200 may be omitted, and pump 10 may provide increased reliability. It should also be appreciated, that in this embodiment of joint 200, regardless of the rotational direction of pivotable member 210 and torque keys 230 (e.g., clockwise or counterclockwise), torque is transferred therebetween via engagement of a greater number of wear pads 124, 134 as compared to joint 100 previously described, thereby offering the potential for enhanced durability.

[0090] Accordingly, the embodiments disclosed herein include embodiments of joints for a progressive cavity device (e.g., a progressive cavity pump or motor) that are tolerant to the wear and erosive effects resulting from exposure to process fluid during operations. Thus, the joints of the embodiments disclosed herein may be implemented within a progressive cavity device without additional seals or fluid barriers, thereby removing the above-mentioned limitations on the operational conditions of the pump. As a result, through use of the embodiments disclosed herein, a progressive cavity pump may be operated in more severe services (which may include higher temperatures and/or pressures), which may not have been suitable for such seals or fluid barriers.

[0091] The discussion herein is directed to various exemplary embodiments. However, one of ordinary skill in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.

[0092] The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.

[0093] In the discussion herein and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to... .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection of the two devices, or through an indirect connection that is established via other devices, components, nodes, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a given axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the given axis. For instance, an axial distance refers to a distance measured along or parallel to the axis, and a radial distance means a distance measured perpendicular to the axis. Further, when used herein (including in the claims), the words “about,” “generally,” “substantially,” “approximately,” and the like, when used in relation to a stated value, mean within a range of plus or minus 10% of the stated value.

[0094] While exemplary embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1 ), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.

Claims

CLAIMS What is claimed is:

1 . A progressive cavity device, comprising: a stator; a rotor positioned within the stator; a driveshaft; and a joint coupling the driveshaft and the rotor, wherein the joint comprises: a pivotable member fixably coupled to and engaged with an end of the driveshaft; wherein the pivotable member has a central axis, a first end proximal the driveshaft, a second end distal the driveshaft, and a radially outer surface extending axially from the first end of the pivotable member to the second end of the pivotable member; a first wear pad mounted on the pivotable member; a torque key disposed about the pivotable member and positioned radially adjacent the radially outer surface of the pivotable member, wherein the torque key is rotationally locked to the rotor, wherein the pivotable member and the torque key are configured to rotate together, and wherein the pivotable member is configured to pivot relative to the torque key; and a second wear pad mounted to the torque key, wherein the second wear pad engages the first wear pad, and wherein engagement of the first wear pad and the second wear pad is configured to transfer torque between the pivotable member and the torque key.

2. The progressive cavity pump of claim 1 , wherein an outer surface of the first wear pad comprises a convex curvature and an outer surface of the second wear pad comprises a planar surface that engages the outer surface of the first wear pad.

3. The progressive cavity pump of claim 1 , wherein at least one of the first wear pad and the second wear pad comprises polycrystalline diamond (PCD).

4. The progressive cavity pump of claim 1 , wherein the radially outer surface of the pivotable member comprises a first convex spherical surface extending axially from the first end, a second convex spherical surface extending axially from the second end, and a plurality of circumferentially-spaced pairs of inclined planar surfaces axially positioned between the first convex spherical surface and the second convex spherical surface; wherein a plurality of first wear pads including the first wear pad are disposed along each pair of inclined surfaces; wherein the torque key has a radially inner surface comprising a first planar surface and a second planar surface circumferentially adjacent the first planar surface, wherein the first planar surface of the torque key is radially opposed one of the pairs of inclined planar surfaces of the pivotable member and the second planar surface of the torque key is radially opposed to another one of the pairs of inclined planar surfaces; wherein a plurality of second wear pads including the second wear pad are disposed along each planar surface of the torque key; wherein each of the plurality of first wear pads engages one of the plurality of second wear pads.

5. The progressive cavity pump of claim 1 , wherein the joint further comprises: a first annular cap comprising: a recess; a concave spherical surface defined within the recess; and a plurality of third wear pads mounted to the concave spherical surface of the first annular cap; a second annular cap comprising: a recess; a concave spherical surface defined within the recess of the second annular cap; and a plurality of fourth wear pads mounted to the concave spherical surface of the second annular cap; wherein the pivotable member is axially positioned between the first annular cap and the second annular capwherein the radially outer surface of the pivotable member comprises a first convex spherical surface extending axially from the first end of the pivotable member and a second convex spherical surface extending from the second end of the pivotable member; a plurality of fifth wear pads mounted on the first convex spherical surface of the pivotable member and a plurality of sixth wear pads mounted on the second convex spherical surface of the pivotable member; wherein the pivotable member is inserted into the recess of the first annular cap such that the plurality of fifth wear pads of the pivotable member engage with the plurality of third wear pads of the first annular cap; wherein the pivotable member is inserted into the recess of the second annular cap such that the plurality of sixth wear pads of the pivotable member engage with the plurality of fourth wear pads of the second annular cap.

6. The progressive cavity pump of claim 5, wherein the concave spherical surface of the first annular cap is offset from the first convex spherical surface of the pivotable member; wherein the concave spherical surface of the second annular cap is offset from the second convex spherical surface of the pivotable member; wherein the first planar surface of the toque key is offset from the corresponding pair of inclined surfaces of the pivotable member; and wherein the second planar surface of the toque key is offset from the corresponding pair of inclined surfaces of the pivotable member.

7. The progressive cavity pump of claim 5, wherein the plurality of third wear pads or the plurality of fifth wear pads comprise PCD, and wherein the plurality of fourth wear pads or the plurality of sixth wear pads comprise PCD.

8. The progressive cavity of pump of claim 5, wherein the annular cap comprises a circumferential outer surface and a recess extending radially into the circumferential outer surface, and wherein the torque key includes a projection seated within the recess of the annular cap such that the torque key is rotationally locked to the annular cap.

9. The progressive cavity pump of claim 1 , wherein the pivotable member includes a plurality of circumferentially-spaced holes extending axially therethrough or the torque key includes a plurality of circumferentially-spaced holes extending axially therethrough.

10. The progressive cavity pump of claim 1 , wherein the pivotable member includes a lug and the first wear pad is mounted to the lug.

11. A joint for coupling a rotor to a driveshaft within a progressive cavity device, the rotor being rotatable within a stator, and the joint comprising: a pivotable member having a central axis, a first end, a second end opposite the first end, and a radially outer surface extending axially from the first end to the second end; wherein the pivotable member includes a throughbore extending axially from the first end and the second end, wherein the throughbore is configured to receive the driveshaft therein; wherein the radially outer surface of the pivotable member includes a first convex spherical surface extending axially from the first end and a second convex spherical surface extending axially from the second end; a plurality of first wear pads disposed along the radially outer surface of the pivotable member axially between the first convex spherical surface and the second convex spherical surface; a torque key having a first end, a second end opposite the first end of the torque key, and a radially inner surface extending axially from the first end of the torque key to the second end of the torque key, wherein the torque key is disposed about the pivotable member with the radially inner surface of the torque key radially adjacent the radially outer surface of the pivotable member; a plurality of second wear pads disposed along the radially inner surface of the torque key, wherein each second wear pad of the torque key engages a corresponding one of the first wear pads of the pivotable member with the radially inner surface of the torque key; wherein the torque key is configured to be rotationally locked to the rotor,; wherein the pivotable member is configured to pivot omnidirectionally relative to the torque key.

12. The joint of claim 11 , wherein the radially outer surface of the pivotable member comprises a plurality of pairs of circumferentially-spaced inclined surfaces axially positioned between the first convex spherical surface and the second convex spherical surface; wherein the plurality of first wear pads are positioned along the pairs of inclined surfaces.

13. The joint of claim 12, wherein the radially inner surface of the torque key comprises a plurality of circumferentially-spaced planar surfaces, wherein one planar surface of torque key is radially opposed one of the plurality of pairs of circumferentially- spaced inclined surfaces of the pivotable member.

14. The joint of claim 11 , wherein at least one of the first wear pads or at least one of the second wear pads comprises polycrystalline diamond (PCD).

15. The joint of claim 14, wherein a concave spherical surface of each first wear pad engages a planar surface of the corresponding one of the second wear pads.

16. The joint of claim 11 , further comprising: a first annular cap comprising: a recess; a concave spherical surface defined within the recess; and a plurality of circumferentially-spaced third wear pads mounted to the concave spherical surface; a second annular cap comprising: a recess; a concave spherical surface defined within the recess of the second annular cap; and a plurality of circumferentially-spaced fourth wear pads mounted to the concave spherical surface of the second annular cap; wherein the pivotable member comprises: a plurality of circumferentially-spaced fifth wear pads mounted on the first convex spherical surface of the pivotable member; a plurality of circumferentially-spaced sixth wear pads mounted on the second convex spherical surface of the pivotable member; wherein the pivotable member is inserted into the recess of the first annular member such that the plurality of third wear pads engage the plurality of fifth wear pads; wherein the pivotable member is inserted into the recess of the second annular member such that the plurality of fourth wear pads engage the plurality of sixth wear pads.

17. The joint of claim 16, wherein the plurality of third wear pads or the plurality of fifth wear pads comprise PCD.

18. The joint of claim 16, wherein the first annular cap comprises a circumferential outer surface and a recess extending radially into the circumferential outer surface, and wherein the torque key includes a projection seated within the recess on the annular cap such that the torque key is rotationally locked the annular cap.

19. The joint of claim 18, wherein a convex curved surface of each of the fifth wear pads of the pivotable member engages a planar surface of one of the third wear pads of the torque key.

20. The joint of claim 16, wherein the first concave spherical surface of the first annular member is offset from the first convex spherical surface of the pivotable member; wherein the second concave spherical surface of the second annular member is offset from the second convex spherical surface of the pivotable member; wherein the radially outer surface of the pivotable member is offset from the radially inner surface of the torque key.