Motor drive shaft spring clutch in electric submersible pump

Abstract

An electric submersible well pump assembly having a coupling. One of the couplings is provided with a lower hub and an upper hub, the lower hub rotates synchronously with the motor shaft, and the upper hub rotates synchronously with the pump shaft. A coil spring clutch engages the two hubs when the motor drives the motor shaft. Stop of the driving rotation of the motor shaft causes the spring clutch to disengage from the upper hub, thereby enabling the pump shaft to rotate the upper hub without rotating the lower hub.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to and the benefit of co-pending U.S. patent application No. 17 / 874,869, filed on July 27, 2022, which is a continuation-in-part of U.S. patent application No. 17 / 307,986, filed on May 4, 2021 (now U.S. Patent No. 11,608,721), which claims priority to U.S. Provisional Application No. 63 / 020,839, filed on May 6, 2020, the entire disclosures of which are incorporated herein by reference in their entirety and for all purposes. Background Art 1. Technical Field

[0003] The present disclosure relates generally to electric submersible pumps (ESPs), and more particularly to a clutch mechanism for preventing a motor drive shaft from rotating before power is supplied to the motor.

[0004] 2. Description of the Prior Art

[0005] ESPs are commonly used in hydrocarbon producing wells. A typical ESP includes an electric motor with a rotating drive shaft that drives a pump. The pump may be a centrifugal pump or another type of pump. The motor is typically an induction electric three-phase AC motor, but permanent magnet motors are also used.

[0006] When the motor is not powered, there are situations where well fluid can flow through the pump. Well fluid flowing through the pump can cause the motor shaft to rotate, creating an electrical charge, especially if the motor is a permanent magnet type. The electrical charge can be dangerous to nearby technicians. One situation can occur when the ESP is run into the well on production tubing. Well fluid can flow up through the pump, causing the motor shaft to rotate in the forward direction. Technicians often deploy power cables at the same time and tie the power cables to the production tubing every 20 feet or so. The terminals at the upper end of the power cables may be exposed, exposing the technician to an electrical shock.

[0007] Another thing that happens when the production tubing is retrieved. Technicians at the wellhead stop the upward pull every 20 feet or so to remove the strips of power cable tied to the production tubing. Well fluid that was previously in the pump and production tubing is expelled from the pump inlet, causing the pump to reverse. The reverse rotation of the pump causes the motor shaft to reverse, which also generates an electrical charge. The charge may be present on the terminals of the power cable, which may be disconnected from the power source during retrieval.

[0008] Additionally, when the ESP is turned off, the column of well fluid in the tubing can flow down through the pump, causing the motor shaft to rotate in the reverse direction. The reverse rotating motor shaft can generate an electrical charge.

[0009] It is known that spiral spring brakes are used for various purposes on helicopter shafts and washing machine shafts. However, spiral spring brakes have not yet been constructed into ESP shaft assemblies and mounted thereon. Summary of the invention

[0010] An example of an electric submersible pump assembly ("ESP") including an electric motor, a pump, and a drive train is disclosed. The drive train of the example is composed of a motor shaft coupled to the electric motor, a pump shaft coupled to the pump, and a connector having a driven hub assembly. The driven hub assembly includes: a driven hub shaft having an end coupled to the pump shaft; a driven hub receptacle connected to an end of the driven hub shaft away from the pump shaft; and a driven hub cavity formed in the driven hub receptacle. Also included is a coil spring having a fixed portion and a flexure portion, the coil spring being inserted into the driven hub cavity, the outer surface of the flexure portion being radially inwardly spaced from the inner surface of the hub receptacle when the spring is in a rotationally static state, and the outer surface of the flexure portion radially expanding to contact the inner surface of the hub receptacle when the spring rotates in a first direction, so that the spring is rotationally coupled to the driven hub assembly and the driving hub assembly, the driving hub assembly having an end coupled to the motor shaft and an opposite end attached to the fixed end of the spring. In one example, energizing the electric motor causes the motor shaft and the driving hub assembly to rotate, thereby causing the spring to rotate in the first direction. Optionally, the radial thickness of the coil in the flexure portion decreases with distance from the fixed portion. In an alternative, the axial thickness of the coil in the flexure portion decreases with distance from the fixed portion. In one embodiment, the drive hub assembly further comprises a drive hub receptacle, a drive hub cavity in the drive hub receptacle that accommodates and is attached to an end of the fixed portion, and a drive hub shaft having an end attached to the electric motor and an opposite end attached to the drive hub receptacle. In one example, the length of the spring disposed in the driven hub receptacle exceeds the length of the spring disposed in the drive hub receptacle. The ESP further optionally comprises a sealing portion disposed between the electric motor and the pump, and wherein the drive train extends through the sealing portion. The spring optionally rotates in a second direction opposite to the first direction, the outer surface of the flexure is radially inwardly spaced from the sidewall of the driven hub receptacle, and the driven hub receptacle is able to rotate freely relative to the spring. Alternatively, the ESP further comprises a clutch spring for preventing the driven hub assembly from rotating.

[0011] Another example of an electric submersible pump assembly ("ESP") includes: an electric motor having a motor shaft that rotates in a first direction when the electric motor is energized; a pump having a pump shaft; and a transmission system having a connector having opposite ends coupled to the motor shaft and the pump shaft, and consisting of a drive hub assembly, a driven hub assembly, and a coil spring, the drive hub assembly and the driven hub assembly each having a receiving portion and a shaft connected to the receiving portion, the receiving portions being coupled to the pump shaft and the motor shaft, respectively, the coil spring having an end attached to the receiving portion of the drive hub assembly and an opposite end inserted into the receiving portion of the driven hub assembly, when in a rotationally static state, the coil spring is radially spaced inwardly from an inner side wall of the receiving portion of the driven hub assembly, and when rotating in a first direction, the coil spring expands radially outwardly to achieve engaging contact, so that the drive hub assembly and the driven hub assembly are rotationally coupled. An example of a helical spring includes a coil, and wherein the radial thickness of the coil in the driven hub assembly decreases with distance from the driving hub assembly, or alternatively, the axial thickness of the coil in the driven hub assembly decreases with distance from the driving hub assembly. In one example, when the spring is rotated in a direction opposite to the first direction, an outer surface of the spring is radially inwardly spaced from a sidewall of the driven hub receptacle, and the driven hub receptacle is able to rotate freely relative to the spring.

[0012] Another example of an electric submersible pump assembly ("ESP") includes: an electric motor having a motor shaft that rotates in a first direction when the electric motor is energized; a pump having a pump shaft; and a drive train having an end rotationally coupled to the motor shaft and an opposite end coupled to the pump shaft. In this example, the drive train includes a connector having a coil spring that radially expands and couples with a driven member in the connector when rotating in the first direction to transmit a rotational force through the connector, and that is disengaged from the driven member and defines a disconnect in the drive train when in a rotationally static state. In this example, the disconnect is also optionally located in the drive train when the spring rotates in a direction opposite to the first direction. The connector also optionally includes a drive member attached to an end of the spring away from the driven member, and wherein the radial and axial dimensions of the spring decrease with distance away from the drive member. In an alternative, the driven member has an annular receiving portion defining a cylindrical cavity into which the spring is inserted and wherein a taper is formed along an inner surface of the receiving portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Having stated certain features and benefits of the present invention, other features and benefits will become apparent when described in conjunction with the accompanying drawings, in which:

[0014] Figure 1is a side view of an ESP supported on a tube in accordance with the present disclosure.

[0015] Figure 2 yes Figure 1 Schematic cross-sectional and exploded view of a coupling between a sealing portion shaft and a motor shaft, the coupling being shown in the position when the motor is not energized.

[0016] Figure 3 When the motor is powered Figure 2 Schematic cross-sectional view of a coupling.

[0017] Figure 4 yes Figure 2 A perspective view of a spring clutch of a coupling, shown removed from the coupling.

[0018] Figure 5 yes Figure 4 A perspective view of an alternative embodiment of a spring clutch shown removed from a coupling assembly.

[0019] Figure 6 yes Figure 2 Schematic cross-sectional view of an alternative embodiment of a coupling.

[0020] Figure 7 yes Figure 2 Schematic cross-sectional view of another alternative embodiment of a coupling.

[0021] Figure 8 yes Figure 7 A perspective view of a spring clutch of a coupling, shown removed from the coupling.

[0022] Fig. 9 yes Figure 2 Schematic cross-sectional view of another alternative embodiment of a coupling.

[0023] Fig.10 yes Figure 2 Schematic side cross-sectional view of another alternative embodiment of a coupling.

[0024] Fig. 10A yes Fig.10 A side cross-sectional enlarged view of a portion of an exemplary coupling.

[0025] Fig.11 is with Fig.10 A side cross-sectional view of an example of a spring used with a coupling.

[0026] Fig. 12A yes Fig.10 A side cross-sectional view of a portion of an exemplary coupling, shown in an inoperative mode.

[0027] Fig. 12B yes Fig.10 A side cross-sectional view of a portion of an exemplary coupling, shown in an operating mode.

[0028] Fig.13 It is in rotation mode Fig.11 Axial view of the spring.

[0029] Fig.14 yes Figure 2 Schematic side cross-sectional view of another alternative embodiment of a coupling.

[0030] While the subject matter is described in conjunction with the embodiments disclosed herein, it should be understood that the scope of the present disclosure is not limited to any particular embodiment. On the contrary, the disclosure is intended to cover all alternatives, modifications, and equivalents thereof. DETAILED DESCRIPTION

[0031] The method and system of the present disclosure are now described more fully below with reference to the accompanying drawings showing embodiments. The method and system of the present disclosure can be in many different forms and should not be construed as being limited to the exemplary embodiments listed herein; on the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and its scope will be fully conveyed to those skilled in the art. Similar numbers throughout the specification represent similar elements. In one embodiment, the use of the term "about" includes + / -5% of the quoted value. In one embodiment, the term "substantially" includes + / -5% of the quoted value, comparison or description. In one embodiment, the use of the term "roughly" includes + / -10% of the quoted value. The terms "upper", "lower", etc. are used only for convenience because the ESP can be operated in a position other than vertical.

[0032] It should be further understood that the scope of the present disclosure is not limited to the exact details of the architecture, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to those skilled in the art. In the drawings and specification, exemplary embodiments have been disclosed, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0033] refer to Figure 1, the well has a casing 11 consolidated in place. In this embodiment, a wellhead (not shown) at the surface supports an electric submersible pump (ESP) 13 on a string of production tubing 15. The ESP 13 includes a pump 17, which is shown as a centrifugal pump having a large number of pump stages, each stage having a rotatable impeller and a non-rotating diffuser. Other types of pumps are also possible, such as positive displacement pumps. The pump 17 has a rotationally driven pump shaft 18 and an inlet 19 for sucking well fluid from the casing 11 and discharging the well fluid into the production tubing 15. A rotary gas separator (not shown) can be mounted to the lower end of the pump 17 for separating gas from liquid in the well fluid flowing into the pump 17. If so, the pump inlet 19 will be located in the gas separator, and the drive shaft within the gas separator can be considered to be a lower extension of the pump shaft 18.

[0034] A motor 21 having a motor shaft 22 drives the pump shaft 18 of the pump 17. The motor 21 is typically a three-phase electric motor filled with a dielectric lubricant. The motor 21 may be a permanent magnet motor having a rotor containing permanent magnets that rotate in response to the electromagnetic field of a non-rotating stator.

[0035] The sealing part 23 connected between the motor 21 and the pump 17 has a pressure equalizer, which is used to reduce the pressure difference between the lubricant in the motor 21 and the external well fluid. Alternatively, the pressure equalizer can be installed below the motor 21. The sealing part 23 has a sealing part shaft 24, which drives the pump shaft 18 and is driven by the motor shaft 22. The power cable 25 with a motor lead extension at the lower end extends from the wellhead downward along the production pipe 15 to the jack on the upper part of the motor 21, which is used to power the motor 21.

[0036] Instead of being supported on production tubing 15, ESP 13 may be supported on a string of coiled tubing, which is a continuous steel pipe deployed from a reel at the surface. The ESP coiled tubing has power cables inside, rather than outside. In this case, motor 21 and seal 23 would be located above pump 17, and pump 17 would discharge fluid into an annulus around motor 21.

[0037] exist Figure 1 In the embodiment of the present invention, the first connector or lower connector 27 connects the motor 21 to the sealing portion 23, and the second connector or upper connector 29 connects the sealing portion 23 to the pump 17. If a rotary gas separator is used, the second connector 29 connects the sealing portion 23 to the gas separator. The third connector connects the gas separator to the pump.

[0038] refer to Figure 2, the clutch coupling 33 will be located in one of the connectors 27, 29, and in this example, the clutch coupling 33 is a motor / seal section coupling located in the first connector 27. The motor shaft 22 has a splined upper end 37 that engages with the lower portion of the clutch coupling 33. The seal section shaft 24 has a lower splined end 41 that engages with the upper portion of the clutch coupling 33. In this example, a conventional coupling (not shown) connects the seal section shaft 24 to the pump shaft 18.

[0039] When the motor 21 is powered on to drive the motor shaft 22, the clutch coupling 33 transmits the drive rotation of the motor shaft 22 to the seal section shaft 24, which in turn transmits the drive rotation to the pump shaft 18. Even if the motor 21 is not powered on, the pump shaft 18 can rotate in the normal drive direction while the ESP 13 is lowered into the sleeve 11 during installation due to the upward flow of well fluid through the pump inlet 19. In addition, after installation, if the motor 21 is turned off, the well fluid flowing back down the pipe 15 can flow downward through the pump 17 and out of the inlet 19, causing the pump shaft 18 to rotate in the opposite direction. In addition, when retracting, sometimes the well fluid can be discharged from the pump 17, causing the pump shaft 18 to rotate in the opposite direction. When the motor 21 is not driving the motor shaft 22, the clutch coupling 33 prevents the pump shaft 18 from rotating in the normal drive direction or in the opposite direction of the motor shaft 22.

[0040] In this embodiment, by positioning the clutch coupling 33 in the first connector 27, the clutch coupling will be immersed in and lubricated by the motor dielectric lubricant of the motor 21. Alternatively, the clutch coupling 33 may be located in the second connector 29, however, the clutch coupling will be immersed in and lubricated by the well fluid instead of the motor lubricant.

[0041] In this example, the clutch coupling 33 has a lower hub or motor end hub 43 with an integrally formed adapter 44 on its lower end. The adapter 44 has an internal splined sleeve 45 that receives the splined upper end 37 of the motor shaft 22. Other types of connections are possible, including making the adapter 44 and lower hub 43 an integral part of the motor shaft 22. In this embodiment, the lower hub 43 is a cylindrical rod, stub shaft or base. The clutch coupling 33 has an upper hub or pump end hub 47 with an adapter 49 having an upwardly facing internal splined sleeve 51 for receiving the lower splined end 41 of the seal section shaft 24.

[0042] The clutch coupling 33 has a spiral clutch spring 53 which includes a spiral turn 55 extending from a lower end or motor end to an upper end or pump end. The lower and upper ends of the spiral turn 63 are free before being mounted to the clutch coupling 33.

[0043] Clutch spring 53 (in another Figure 4 ) can be made by forming a spiral cut through the wall of a tubular metal block. Figure 3 As shown, each helical turn 55 has a rectangular shape in this example when viewed in axial cross section. When viewed from the upper end downward, the helical turn 55 defines a counterclockwise helical path extending in the opposite direction to the drive direction of the motor shaft 22. In these embodiments, the normal drive direction of the motor shaft 22 is clockwise, but it can also be the opposite direction.

[0044] In this embodiment, the lower end of the clutch spring 53 is fixed to the lower hub 43 to rotate therewith. One technique for fixing the clutch spring 53 to the lower hub 43 uses a shrink ring or clamp 57 that tightly clamps the lower portion of the clutch spring 55 around the lower hub 43. The shrink ring 57 can be a solid annular member that is heat treated to shrink its diameter so that it can be first inserted on the lower hub 43 and then shrunk to tightly clamp the lower end of the clutch spring 53 to the lower hub 43. For example, the shrink ring 57 can be a shape memory alloy such as Nitinol, which shrinks when heat is applied and maintains a smaller diameter after the heat is removed. The shrink ring 57 only clamps the lower portion of the spiral turns 55, and the remaining turns 55 thereof can maintain their original diameter.

[0045] In this embodiment, the upper hub 47 is a receptacle that is open at the lower end. The upper hub 47 has an inner cylindrical sidewall 61 that faces inwardly toward the longitudinal axis 63 of the clutch coupling 33. The upper portion of the clutch spring helical turns 55 fits within the receptacle defined by the upper hub 47. Initially, the upper portion of the helical turns 55 are radially inwardly spaced a slight gap from the upper hub sidewall 61, or they may be in slight contact. Due to manufacturing tolerances, the contact surface of the helical turns 55 is only a few degrees. In this example, the full 360 degrees of the turns of the clutch spring 53 will not initially contact the sidewall 61.

[0046] refer to Figure 3 , when the motor shaft 22( Figure 1 ) When the lower hub 43 is driven as shown by the arrow, the clutch spring 53 will rotate synchronously. The upper portion of the spiral turns 55 expands radially outward in response to the centrifugal force of the rotation, thereby closely fitting with the inner side wall 61 of the upper hub. The fit causes the upper hub 47 to rotate synchronously, driving the sealing portion shaft 24 ( Figure 2 ) and pump shaft 18( Figure 1 Once the motor 21 stops driving the motor shaft 22, there will be no more fit. The diameter of the helical turns 55 in the upper hub 47 will shrink and will lose fit with the side wall 61 due to the loss of centrifugal force.

[0047] If the pump shaft 18 ( Figure 1) begins to rotate in the normal drive direction during initial installation, this drive direction rotation will cause the seal portion shaft 24 and the upper hub 47 to rotate, but the clutch spring 53 will not rotate because there is clearance between the helical turns 55 and the upper hub sidewall 61. Similarly, if the pump shaft 18 begins to rotate in the opposite direction when the motor 21 is not powered, the upper hub 47 will also rotate in the opposite direction, but the clutch spring 53 will not rotate in the opposite direction because it is not in contact with the sidewall 61.

[0048] Figure 5 A spring clutch 65 is shown as an alternative embodiment of the spring clutch 53. A screw 67 is suspended from the closed lower end of the spring clutch 65 instead of the shrink ring 57 ( Figure 2 The screw 67 engages with the threaded hole in the lower hub 43 to secure the lower portion of the spring clutch 65 to the lower hub 43 for rotation. The upper portion of the spring clutch 65 will rotate in response to the drive of the lower hub 43 to engage with the lower hub 43. Figure 2-4 The same manner as described above is used for the upper hub side wall 61 ( Figure 2 ) are engaged. When the motor shaft 22 rotates, the thread of the screw 67 is in a tightening direction.

[0049] exist Figure 6 In an alternative embodiment of the present invention, the coupling 69 has a lower transition joint 71, which may have a similar Figure 2 The lower hub 73 is connected to the lower conversion joint 71 and includes an upwardly facing receiving portion with an upper end opening and an inwardly facing cylindrical side wall 74. The upper conversion joint 75 and the upper hub 77 can be connected to the lower conversion joint 71. Figures 2 to 3 The upper hub 77 is a downwardly facing receiving portion having an inwardly facing side wall 79 .

[0050] The clutch spring 81 can be Figure 2 79. The clutch spring 81 is similar to the clutch spring 53 of FIG. 79. In this example, the lower portion of the helical turns 83 will form an initial friction or interference engagement with the sidewall 74 of the lower hub 73. The upper portion of the helical turns 83 will not initially conform to the upper hub sidewall 79. Instead, the upper portion of the helical turns 83 will be slightly spaced from or lightly in contact with the upper hub sidewall 79. Due to manufacturing tolerances, the contact surface (if any) between the clutch spring 81 and the upper hub sidewall 79 is only a few degrees. A full 360 degree contact between the clutch spring 81 and the upper hub sidewall 79 will not initially occur.

[0051] When the motor 21 ( Figure 1) When the motor shaft 22 is driven, the lower hub 73 will rotate the clutch spring 81 synchronously due to the initial interference fit with the lower hub sidewall 74. The driving direction rotation causes the lower portion of the helical turns 83 to expand and more closely fit the lower hub sidewall 74. The driving direction rotation of the lower hub 73 causes the diameter of the upper helical turns 83 to expand and begin to fit with the upper hub sidewall 79. The rotation is transmitted from the upper hub 77 to the pump shaft 18 ( Figure 1 ). Rotation of the pump shaft 18 in either direction when the motor is not energized will not cause rotation of the lower hub 73 for the same reasons as explained in conjunction with the first embodiment.

[0052] exist Figure 7 In the embodiment of the present invention, the clutch coupling 85 has a lower hub 87, which is a cylindrical rod similar to Figure 2 The lower hub 43 in the middle. The lower adapter 89 with a splined sleeve depends downwardly from the lower hub 87 and can be integral with the lower hub. The upper adapter 91 and the upper hub 93 with the inward sidewall 94 can be as shown. Figure 2 or Figure 7 The upper hub 93 is also a receiving portion having an inwardly facing side wall 94 .

[0053] In this example, the clutch spring 95 and the clutch spring 53 ( Figure 2 ) is different in that it has a lower helical turn 97 that rotates or extends in the opposite direction to the upper helical turn 99. When the motor 21 is powered, the lower helical turn 97 rotates or extends in the direction opposite to the motor shaft 22 ( Figure 1 ). The lower helical turns 97 are inserted in an initially interfering manner on the lower hub 87. The motor shaft 22 drives the lower hub 87 to rotate, causing the lower helical turns 97 to contract and more closely fit the lower hub 87. The upper helical turns 99 initially do not fit with the upper hub sidewall 94. The driving direction rotation of the clutch spring 95 causes the upper helical turns 99 to expand to fit closely with the upper hub sidewall 94.

[0054] The lower transition fitting 89 may have an outer flange 100 , and the lower end of the clutch spring 95 may abut the flange 100 . Figure 8 is a graphical representation of clutch spring 95 .

[0055] Fig. 9 The clutch coupling 102 in FIG. 1 is another embodiment. It has a lower hub 101, which is a rod or base with a cylindrical exterior. The lower hub 101 has an upper extension 101a, which is also a rod and has an outer diameter that is smaller than the outer diameter of the lower hub 101. The lower adapter 105 is connected to the lower hub 101 and has a spline end 37 ( Figure 2) sleeve. The lower conversion joint 105 has an outer flange 103. The lower hub 101, the flange 103, the lower conversion joint 105 and the upper extension 101a are fixed together and rotate together.

[0056] The upper hub 107 is a receiving portion having a closed upper end 107a and a cylindrical wall 107b having an inwardly facing side wall 109. The upper end 107a and the cylindrical wall 107b are fixed to each other and rotate together. The upper conversion joint 111 is connected and fixed to the closed upper end 107a of the upper hub 107. The upper conversion joint 111 has a spline end 41 ( Figure 2 ) spline sleeve. The lower hub extension 101a extends upward in the upper hub 107 and can be adjacent to the upper closed end 107a. However, when the pump shaft 18 ( Figure 1 ) rotates and the motor shaft 22 does not rotate, the upper closed end 107a is able to rotate relative to the lower hub extension 101a. Bearing 113 is schematically shown and is located at the junction of the top of the lower hub extension 101a and the closed upper end 107a. This is to facilitate the rotation of the upper closed end 107a relative to the lower hub extension 101a. The upper hub cylindrical wall 107b extends downwardly into the junction with the lower hub flange 103. Bearing 115 is located at this junction to improve positioning and performance. When the pump shaft 18 ( Figure 1 ) rotates and the motor shaft 22 does not rotate, the bearing 115 enables the upper hub cylindrical wall 107b to rotate relative to the lower hub flange 103.

[0057] The clutch spring 117 may be configured to Figure 7 1. The clutch spring 117 has a lower helical turn 119 that surrounds the lower hub 101 with an initial interference fit. The outer diameter of the lower helical turn 119 is separated from the inwardly facing sidewall 109 of the upper hub by a gap. In this example, the clutch spring 117 has an upper helical turn 121 that extends helically in an opposite direction from the lower helical turn 119. The upper helical turn 121 may have the same inner and outer diameters as the lower helical turn 119. However, the inner diameter of the upper helical turn 121 is separated from the lower hub extension 101a by an annular gap because the outer diameter of the lower hub extension 101a is smaller than the outer diameter of the lower hub 101. The outer diameter of the upper helical turn 121 may initially be spaced a little distance from the upper hub sidewall 109, as described in other embodiments.

[0058] When the motor 21 drives the motor shaft 22 ( Figure 1), the clutch spring 117 rotates in the same direction, causing the lower helical turns 119 to contract and fit more closely to the lower hub 101. The upper helical turns 121 expand to fit the upper hub sidewall 109, causing the upper hub 107 to rotate synchronously with the lower hub 101. When the motor 21 is turned off and the pump shaft 18 ( Figure 1 ) begins to rotate in either direction, the upper hub 107 will rotate synchronously. However, the clutch spring 117 will not rotate because once the motor shaft 22 stops driving, the diameter of the upper helical turns 121 will shrink enough to lose contact with the upper hub sidewall 109. Therefore, the lower hub 101 and the motor shaft 22 will not rotate. Bearings 113 and 115 facilitate the rotation of the upper hub 107 relative to the lower hub 101. An alternative embodiment (not shown) using a locating bearing similar to bearings 113 and 115 can use a shrink ring 57 and clutch spring 53 ( Figure 3 )replace.

[0059] See now Fig.10 , shown in side cross-sectional view is an optional means for attaching the shafts 18, 24, 22 ( Figure 1 ) are coupled together. The connector 130 includes an outer shell 132 shown as a generally annular structure having an inner cavity 133 and an end connected to an annular base 134. Alternatively, the shell 132 and the base 134 are combined in a single structure. A hole 135 extends axially through the base 134 along the axis Ax. The end of the shell 132 away from the base 134 is connected to a portion 136, and the end of the base 134 away from the shell 132 is connected to a portion 138. The portions 136, 138 optionally represent the ESP 13 ( Figure 1 ) of different parts, such as pump portion 21, seal portion 23 and pump portion 17. A connector 130 is also optionally provided in place of connector 27 and / or in place of connector 29. Exposed substantially coaxially within base 134 is a conversion joint 140 having a splined sleeve 142 formed axially therein. One side of sleeve 142 is formed to accommodate an end of shaft 144 therein. In one example, shaft 144 represents motor shaft 22 or seal shaft 24 ( Figure 1). In the example shown, the adapter 140 rotationally couples the shaft 144 with a drive hub assembly 146 shown within the housing 132; the assembly 146 includes a drive hub shaft 148 extending axially within the base bore 135 and forming a splined sleeve 142 to mate with the shaft 144. The drive hub receptacle 142 also connects the ends of the shaft 148 on the opposite end of the adapter 140 and is disposed within the bore 135. The receptacle 150 includes a base 151 within the housing 132 and an annular sidewall 152 within the cavity 133, the base being shown extending radially from the end of the shaft 148, the annular sidewall protruding axially away from the outer periphery of the base. A drive hub cavity 154 is defined within the sidewall 152 facing away from the shaft 148. The connector 130 also includes a driven hub assembly 156, which includes an extended driven hub shaft 158, which protrudes axially to the outside of the shell 132 away from the driving hub assembly 146. The driven hub assembly 156 also includes a driven hub accommodating portion 160, which is composed of a base 161 in the shell 132 and an annular side wall 162 in the cavity 133. The base protrudes radially from the end of the shaft 158, and the annular side wall protrudes axially away from the base and toward the outer periphery of the assembly 146.

[0060] The shafts 158, 148 protrude through openings 164, 165 formed through bulkheads 166, 167 formed on the end of the housing 132 opposite the base 134 and bulkhead 167 formed on the end of the base 134 adjacent the housing 132. Bearings 168, 169 are disposed within the openings 164, 165 and between the shafts 158, 148, respectively. The driven hub assembly 156 includes a cavity 170 formed within the sidewall 162. In the example shown, the connector 130 and the attachment shaft 144 are configured to transfer rotational energy from the motor 21 to the pump 17 ( Figure 1 ) is a portion of a drive train 171 of the pump 17. For discussion of the drive train 171 herein, uphole refers to toward the pump 17, and downhole refers to toward the motor 21. In examples described in more detail below, the drive train 171 optionally includes a disconnect, which refers to one or more locations where adjacent axial portions of the drive train 171 are rotationally decoupled from each other or coupled to other components that limit or inhibit rotation of the drive train 171.

[0061] Still reference Fig.10, a coil spring 172 is shown inside the housing 132 and has been shown to have a longitudinal portion within the driving hub cavity 154 and another longitudinal portion within the driven hub cavity 170. In the example shown, the sidewalls 142, 162 completely surround the spring 172, and the length of the spring 172 is substantially the same as the combined length of the cavities 154, 170; in an alternative, the length of the spring 172 is different from the combined length of the cavities 154, 170. As shown, the coil spring 172 has a generally annular configuration, an optional cylindrical spacer 174 is inserted into an axially extending hole in the spring 172, and a dowel 175 is also optionally inserted into the axial opening from the opposite side of the spacer 174 and aligned with the opening formed axially in the base 151, 161. An optional annular bearing 176 is shown to be disposed in the annular space between the outer surface of the sidewalls 152, 162 and the inner surface of the housing 132. The bearing 176 is an annular member having an axial length greater than its radius, and surrounds the junction where the side walls 152 , 162 abut against each other.

[0062] Fig. 10A Shown in detail Fig.10 1 and 130 and includes a joint I representing different portions of the spring 172. A taper 177 is schematically shown along the inner surface of the side wall 162, which tapers to represent the change in diameter of the cavity 133. The joint I is located in the plane where the terminal ends of the side walls 152, 162 abut and contact. The fixed portion 178 is the portion of the spring 172 within and surrounded by the side wall 152, and as shown, the portion is press-fitted within the side wall 152 so that the drive hub assembly 146 and the spring are rotationally coupled to each other. In this example, the shaft 148 is rotated along the curved arrow A R The clockwise rotation of the spring 172 causes the spring 172 to rotate in the same rotational direction. The flexure 180 is the portion of the spring 172 that is within and surrounded by the sidewall 162. In the example shown, when the spring 172 is static or otherwise not rotating, a radial gap 182 exists between the outer surface of the flexure 180 and the inner surface of the sidewall 162. Fig. 10A Also provided is a length L representing the axial length of the fixing portion 178 along the axis Ax. 178 and the length L representing the length of the flexure 180 along the axis Ax 180 In the example shown, the length L 180 Greater than length L 178 .

[0063] See now Fig.11 The spring 172 is shown in a side cross-sectional view as being composed of coils 1831-183 within the fixed portion 178 of the spring 172. n and coils 1841-184 in the flexure 180 of the spring mIn the alternative shown, the coil width W184 1-n Along the spring axis A 172 changes, and from the transition section 186 to the coil 184 m The terminal end of the spring 172 at the transition section will experience a greater width difference. m Radial thickness T184 1-m The voltage decreases continuously before the second transition section 187 and at the coil 184 m The previous period remained largely unchanged. Fig.11 In the example of FIG. 1 , the spring 172 is in a static or non-rotating configuration and the spring outer diameter OD 172 is substantially constant along the entire axial length of the spring 172. In addition, the spring inner diameter ID 172 It is also shown that the axial length along the fixed portion 178 and the axial length along the flexure portion 180 are substantially constant until the ID 172 It increases at transition section 186 and remains substantially constant from second transition section 187 to the end of spring 172. In an alternative embodiment, the spring inner diameter ID 172 From the transition section 186 to the last coil 184 m The overall distance increases.

[0064] Fig. 12A 1 is an example representation of a spring 172 in a rotationally static configuration, where a gap 182 exists between the inner surface of the sidewall 162 and the flexure outer diameter OD180 when the spring 172 is in a rotationally static configuration. static between. Fig. 12B 1 is an example of a spring 172 that rotates (or is being rotated) in a first direction ARI. In a non-limiting example, the spring 172 is rotated by causing the motor 21 ( Figure 1 ) is energized to rotate the shaft 22, 144 and the drive hub assembly 146, which in turn rotates the spring 172 in direction A through the fixed relationship between the spring 172 and the drive hub receiving portion 150. R1 Rotation. Spring 172 moves along A R1 The direction of rotation causes the coil 184 in the flexure 180 to 1-m At least some of the outer diameter of the outer diameter of the radial expansion to have an outer diameter OD180 dynamic . Coil 184 1-m The radial expansion causes the outer surface of the flexure 180 to engage the inner surface of the side wall 162 and to engage the spring 172 with the driven hub assembly 156 ( Fig.10 ) is rotationally coupled so that the rotational force is transmitted through the connector 130 and continues to rotate along the transmission system 171 to drive the pump 17 ( Figure 1In one non-limiting example of operation, the width W184 of the coil 184 of the spring 172 is 1-m and thickness T194 1-m The important dimension setting of will affect the physical properties of the flexure 180, so that the flexure 180 is R1 When rotated, it becomes rotationally coupled with the driven hub assembly 156 .

[0065] Fig.13 The figure shows the rotation mode, in the clockwise direction A R1 and around axis A 172 An axial view of the end of the rotating spring 172 pointing downhole. As shown, the spring 172 and the coil 184 m The free end 189 on the coil 184 is pushed radially outward due to the rotation of the spring 172. 1-m The outer radial displacement of is in response to the centrifugal force applied to the spring 172 when rotated.

[0066] When the spring 172 is in a dynamic static state, such as when the motor 21 ( Figure 1 ) when no power is supplied and no rotation is produced in its shaft 22, the coil 184 of the flexure 180 1-m At their static outer diameter OD180 static , so that the gap 182( Fig. 12A ) exists between the spring 172 and the driven hub assembly 156. Due to the gap 182, the rotation of the driven hub receiving portion 160 is not transmitted to the spring 172, and no rotational force is transmitted through the connector 130; this prevents the motor 21 ( Figure 1 ) reverse rotation. Fig.10 , in the alternative, the counterclockwise rotational force is shown as A R2 , and direction A R1Instead, the counterclockwise rotational force is applied to the shaft 158 ​​on the side opposite the spring 172. For the purposes of this discussion, there is initially a gap 182 between the spring 172 and the driven hub assembly 156. In the example shown, when rotating counterclockwise, centrifugal force causes the spring 172 to expand. Any friction between the spring 172 and the opposing surfaces of the receptacle 150 generated by the counterclockwise rotation of the spring 172 is insufficient to engage the spring 172 with the receptacle 150, so that when the shaft 158 ​​rotates counterclockwise as described above, the rotational force is not transmitted along the entire length of the drive train 171. The disconnect B is defined in the drive train 171 by the presence of the gap 182. The use of the connector 130 avoids the risk of reverse rotation of the motor 21, such as reverse rotation caused by components in the drive train 171 located above the connector 130. In one embodiment, the disconnect is selectively formed in the drive train 171 when the spring 172 is not rotating. Optionally, the spring 172 is configured so that when the spring 172 is rotated in direction A, the disconnect is formed in the drive train 171. R2 When rotating, a disconnect is formed in the drive train 171. In one non-limiting example of operation, the motor 21 ( Figure 1 ) is energized. The motor 21 is energized to make the shaft 22 and the shaft 144 ( Fig.10 ) along the rotation direction A R1 When the speed of the motor 21 increases and reaches a rotational speed in the range of about 200 revolutions per minute ("rpm") to about 300 rpm (and in direction A R1 ), the spring 172 begins to expand radially and rotationally engage the driven hub receptacle 160. Rotationally engaging the driven hub receptacle 160 with the spring 172 causes the driven hub assembly 156 to rotate at the same speed as the spring 172, and in turn causes the drive train 171 and the pump shaft 18 ( Figure 1 ) rotates. In this example, the speed of motor 21 continues to increase until it reaches a normal operating speed of about 3600 rpm, and continues to operate at this speed until its operation is adjusted, such as by suspending the power supply. In an alternative embodiment, when the production pipe 15 ( Figure 1 ), the liquid flows back through the pump 17 and across its impeller (not shown), causing the impeller and the pump shaft 18 to rotate in the counterclockwise direction, which in turn causes the shaft 158 ​​to rotate in the counterclockwise direction AR2. As described above, when the shaft 158 ​​rotates in the counterclockwise direction AR2, the disconnection portion B in the connector 130 is opened by the gap 182 ( Fig. 10A ) are formed so that adjacent portions of the transmission system 171 (ie, the driven hub assembly 156 and the driving hub assembly 146) are rotationally decoupled from each other.

[0067] See now Fig.14, shown in side cross-sectional view is an alternative example of a connector 130A, which is similar to Fig.10 140A provides a coupling between the shaft 144A and the shaft 148A of the drive hub assembly 146A. Fig.14 The example also includes a driven hub assembly 156A having a downward cavity 170A and an upward receptacle 190A formed by a sidewall 162A extending axially through a base portion of the driven hub assembly 156A and away from the driving hub assembly 146A. Within the receptacle 190 is a clutch spring 192A having a helical orientation opposite that of the spring 172A. A spacer 193A is disposed in an annular space between the shaft 158A and the inner surface of the spring 192A, and an insert 194A is disposed in the cavity 133A having a radial base and an axial sidewall 194A that surrounds a portion of the spring 192A. The spring 192A has a fixed portion 196A attached to the upward receptacle 190A. And includes a flexure 198A surrounded by a sidewall 195A. In this example, by moving in a direction A R1 In the opposite direction ( Fig.14 A R2 ) rotates the shaft 158A so that the coils in the flexure 198A protrude radially outward and engage with the inner surface of the side wall 195A, thereby preventing rotation of the shaft 158A. Optionally, a bolt 200A is shown as being inserted axially through the partition 166A for securing the insert 194A within the housing 132A.

[0068] Therefore, the invention described herein is well adapted to carry out these objects and achieve the objects and advantages mentioned, as well as other objects and advantages inherent therein. Although only a few embodiments of the invention are given for the purpose of disclosure, there are many changes in the details of the process for achieving the desired results. These and other similar modifications will be obvious to those skilled in the art and are intended to be covered by the scope of the claims. For example, the spring clutch can be installed in the coupling between the sealing part shaft 24 and the pump shaft 18, instead of being installed between the motor shaft 22 and the sealing part shaft 24.

Claims

1. An electric submersible pump assembly ("ESP"), the electric submersible pump assembly comprising: Electric motor; Pumps; and A transmission system, the transmission system comprising: a motor shaft coupled to the electric motor, a pump shaft coupled to the pump, and A connector, comprising: A driven hub assembly, the driven hub assembly comprising: a driven hub shaft having an end coupled to the pump shaft, a driven hub receiving portion connected to an end of the driven hub shaft remote from the pump shaft, and a driven hub cavity, the driven hub cavity being formed in the driven hub receiving portion; A coil spring, the coil spring comprising a fixed portion and a flexure portion, the coil spring being inserted into the driven hub cavity, when the spring is in a rotational static state, The outer surface of the flexure is radially inwardly spaced from the inner surface of the hub receiving portion, and when the spring rotates in a first direction, the outer surface of the flexure radially expands to contact the inner surface of the hub receiving portion, so that the spring is rotationally coupled to the driven hub assembly, A drive hub assembly has an end coupled to the motor shaft and an opposite end attached to the fixed end of the spring.

2. The ESP of claim 1, wherein energizing the electric motor rotates the motor shaft and the drive hub assembly, thereby rotating the spring in the first direction. 3 . The ESP of claim 1 , wherein a radial thickness of the coil in the flexure portion decreases with distance from the fixed portion. 4 . The ESP of claim 1 , wherein an axial thickness of the coil in the flexure portion decreases with distance from the fixed portion.

5. The ESP of claim 1 , wherein the drive hub assembly further comprises a drive hub receptacle, a drive hub cavity in the drive hub receptacle that receives and is attached to an end of the fixed portion, a drive hub shaft having an end attached to the electric motor and an opposite end attached to the drive hub receptacle. 6 . The ESP according to claim 5 , wherein the length of the spring disposed in the driven hub receptacle exceeds the length of the spring disposed in the driving hub receptacle.

7. The ESP of claim 1, further comprising a sealing portion disposed between the electric motor and the pump, and wherein the drive train extends through the sealing portion.

8. The ESP of claim 1, wherein when the spring rotates in a second direction opposite to the first direction, the outer surface of the flexure is spaced radially inwardly from a sidewall of the driven hub receptacle and the driven hub receptacle is freely rotatable relative to the spring.

9. The ESP of claim 1, further comprising a clutch spring for preventing the driven hub assembly from rotating.

10. An electric submersible pump assembly ("ESP"), the electric submersible pump assembly comprising: an electric motor having a motor shaft that rotates in a first direction when power is supplied to the electric motor; A pump having a pump shaft; and A drive train including a connector having opposite ends coupled to the motor shaft and the pump shaft, the connector comprising: a driving hub assembly and a driven hub assembly, each of the driving hub assembly and the driven hub assembly comprising a receiving portion and a shaft connected to the receiving portion, the receiving portion being coupled to the pump shaft and the motor shaft, respectively, and A coil spring having an end attached in the driving hub assembly receiving portion and an opposite end inserted into the driven hub assembly receiving portion, wherein the coil spring is radially inwardly spaced from an inner sidewall of the driven hub assembly receiving portion when in a rotationally static state, and when rotating in the first direction, the coil spring radially expands outwardly into engaging contact so that the driving hub assembly and the driven hub assembly are rotationally coupled.

11. The ESP of claim 10, wherein the helical spring comprises coils, and wherein a radial thickness of the coils in the driven hub assembly decreases with distance from the driving hub assembly.

12. The ESP of claim 10, wherein the helical spring comprises coils, and wherein an axial thickness of the coils in the driven hub assembly decreases with distance from the driving hub assembly.

13. The ESP of claim 10, wherein when the spring is rotated in a direction opposite to the first direction, the outer surface of the spring is spaced radially inwardly from the sidewall of the driven hub receptacle and the driven hub receptacle is freely rotatable relative to the spring.

14. An electric submersible pump assembly ("ESP"), the electric submersible pump assembly comprising: an electric motor including a motor shaft that rotates in a first direction when power is supplied to the electric motor; A pump including a pump shaft; and a drive train having an end rotationally coupled to the motor shaft and an opposite end coupled to the pump shaft, the drive train comprising: A connector having a coil spring which radially expands and couples with a driven member in the connector when rotated in the first direction to transmit a rotational force through the connector, and which, when in a rotationally static state, separates from the driven member and defines a disconnect in the drive train.

15. The ESP of claim 14, wherein the disconnect portion is located in the power train when the spring is rotated in a direction opposite to the first direction.

16. The ESP of claim 14, the connector further comprising a drive member attached to an end of the spring distal from the driven member, and wherein radial and axial dimensions of the spring decrease with distance away from the drive member.

17. The ESP of claim 14, wherein the driven member includes an annular receiving portion defining a cylindrical cavity into which the spring is inserted, and wherein a taper is formed along an inner surface of the receiving portion.

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