Flexible connection device for series motor of electric high-speed booster pump at bottom of oil and gas well

Abstract

The application relates to the technical field of series connection type motors, and particularly discloses a flexible connecting device for a series connection type motor of an oil-gas well bottom electric high-speed booster pump, which comprises a universal joint, an inner bellows is arranged on the universal joint, the inner bellows is coaxially arranged with the universal joint and has a spacing, an outer bellows is coaxially arranged on the outer periphery of the inner bellows and has a spacing with the inner bellows, a first connecting sleeve and a second connecting sleeve are respectively arranged at the two ends of the universal joint, the two ends of the inner bellows and the outer bellows are respectively connected to the adjacent surfaces of the first connecting sleeve and the second connecting sleeve, and the first connecting sleeve and the second connecting sleeve are respectively connected to the shells of two groups of motors at the ends away from the outer bellows. The flexible connecting device improves the problems of unreliable transmission and easy pollution when the rotating shafts of the two motors have an included angle, and realizes reliable transmission, double protection and stable operation of the series connection type motor.

Description

Technical Field

[0001] This application relates to the field of series motor technology, and in particular to a flexible connection device for a series motor of an electric high-speed booster pump at the bottom of an oil and gas well. Background Technology

[0002] In scenarios requiring high power output, such as downhole drives and industrial transmissions, single motors, limited by size and power density, struggle to meet high load demands. Connecting multiple motors in series to increase total power has gradually become the mainstream solution. However, during installation and operation, factors such as equipment assembly errors and working condition deformations (e.g., the bending environment of the casing in the downhole drilling section) often cause adjacent motor shafts to not be strictly coaxial, resulting in a certain angle between them.

[0003] Traditional rigid connection structures cannot accommodate such angular displacement deviations, easily leading to torque transmission interruption, excessive wear of the shaft and connecting components, and even transmission failure. Furthermore, existing connection methods lack effective protective structures, allowing external dust, liquids, and impurities to easily penetrate the shaft connection areas, accelerating component corrosion and wear, and shortening equipment lifespan.

[0004] In addition, the vibration and shock of the motor during operation are easily transmitted through rigid connections, which not only amplifies the noise, but also causes the power lines to become entangled and rubbed, increasing the risk of circuit failure and making it difficult to meet the requirements for transmission stability, reliability and protection performance under complex working conditions.

[0005] Therefore, there is an urgent need for a series motor interface structure that can adapt to shaft angle deviation and has both protection and stable transmission functions. Summary of the Invention

[0006] This application provides a flexible connection device for a series motor in an oil and gas well bottom-hole electric high-speed booster pump, which solves the problems of unreliable transmission and susceptibility to contamination when the shafts of the two motors are at an angle, and achieves reliable transmission, dual protection and stable operation of the series motor.

[0007] This invention provides a flexible connection device for a series motor of a high-speed electric booster pump at the bottom of an oil and gas well, comprising: a universal coupling disposed between the shafts of two sets of motors, with both ends of the universal coupling connected to the ends of the shafts of the two sets of motors respectively; the universal coupling allows a certain angle between the two shafts and transmits the torque and motion of one shaft to the other shaft under this angle condition; an inner bellows is sleeved on the universal coupling, the inner bellows being coaxially arranged with the universal coupling and having a gap; an outer bellows is coaxially sleeved on the outer circumference of the inner bellows and having a gap with the inner bellows; a first connecting sleeve and a second connecting sleeve are respectively disposed at both ends of the universal coupling; wherein the ends of the inner bellows and the outer bellows are respectively connected to the adjacent surfaces of the first connecting sleeve and the second connecting sleeve; the ends of the first connecting sleeve and the second connecting sleeve away from the outer bellows are respectively connected to the housings of the two sets of motors.

[0008] In one possible implementation, both the first connecting sleeve and the second connecting sleeve include a connecting portion, the connecting portion including: a ring body, the inner ring face being disposed on the outer peripheral surface of the universal coupling; wherein the two sets of adjacent surfaces of the ring bodies of the first connecting sleeve and the second connecting sleeve are respectively connected to the inner bellows and the outer bellows; one end of the two sets of ring bodies away from the inner bellows and the outer bellows extends into the housing of the motor and contacts the inner wall of the housing of the motor.

[0009] In one possible implementation, both sets of rings of the first connecting sleeve and the second connecting sleeve are provided with motor power line through holes; the motor power line through holes are arranged through both sets of rings; wherein the extension direction of the motor power line through holes is parallel to the axis of the rings; the cavity of the center of the rings is connected to the cavity of the center of the inner bellows to form a motor shaft connection channel; the adjacent ends of the rotating shafts of the two sets of motors and the universal coupling are all arranged in the motor shaft connection channel.

[0010] In one possible implementation, the connecting portion further includes: at least one prestressed hanging bolt, with both ends respectively connected to two sets of the rings; and a hanging hole, extending in a direction parallel to the axis of the rings and penetrating through the two sets of rings; wherein the prestressed hanging bolt is disposed in the hanging hole; the diameter of the hanging hole is larger than the screw diameter of the prestressed hanging bolt; and a plurality of the prestressed hanging bolts are distributed in a ring on the end face of the rings.

[0011] In one possible implementation, the connecting portion further includes: an extension tube disposed at one end of the ring body away from the inner corrugated tube and the outer corrugated tube; wherein the inner wall of the extension tube smoothly transitions with the inner wall of the ring body, and the motor shaft connecting channel extends into the two sets of extension tubes.

[0012] In one possible implementation, the second connecting sleeve further includes: a motor power line positioning plate, which is annular and disposed at one end of the extension tube of the second connecting sleeve away from the annular body; wherein the surface of the motor power line positioning plate is provided with a plurality of auxiliary through holes spaced apart, and the motor power line passes through the auxiliary through holes and enters the motor power line through holes.

[0013] In one possible implementation, the motor housing is further fitted with an obstacle avoidance device, which includes: a telescopic mechanism and an elastic obstacle avoidance unit; wherein the telescopic mechanism is installed on the circumferential outer wall of the motor housing, and its extended end is connected to the elastic obstacle avoidance unit; a limiting sleeve assembly is fitted over the outer wall of the telescopic mechanism, and the telescopic mechanism is used to drive the elastic obstacle avoidance unit to slide within the limiting sleeve assembly; the elastic obstacle avoidance unit moves towards the motor housing during the process of entering the limiting sleeve assembly.

[0014] In one possible implementation, the telescopic mechanism includes: a first mounting ring fitted onto the circumferential outer wall of the motor housing; multiple electric push rods, one end of which is spaced apart on one side of the first mounting ring; a second mounting ring coaxial with the first mounting ring and located at the other end of the multiple electric push rods; a guide ring coaxial with the second mounting ring and spaced apart on the side of the second mounting ring away from the first mounting ring; wherein the circumferential outer wall of the guide ring is provided with a plurality of guide holes spaced apart; and multiple drive rods, one end of which is spaced apart on the side of the second mounting ring away from the electric push rods; each drive rod passes through the guide holes and is connected to the elastic obstacle avoidance unit.

[0015] In one possible implementation, the elastic obstacle avoidance unit includes: a slide rail sleeve, spaced apart on the side of the second mounting ring away from the first mounting ring, and fixedly sleeved on the circumferential outer wall of the motor housing; multiple slide grooves, spaced apart on the circumferential outer wall of the slide rail sleeve, and respectively parallel to the axis of the slide rail sleeve; multiple first slide rods and multiple second slide rods, with the multiple first slide rods and second slide rods alternately arranged in each of the slide grooves; a transition sleeve, slidably sleeved on the circumferential outer wall of the motor housing, with one end connected to the guide ring and the other end connected to the multiple first slide rods; a third mounting ring, slidably sleeved on the circumferential outer wall of the transition sleeve, with one end of the multiple second slide rods connected to the side wall of the third mounting ring; the ends of the first slide rods and second slide rods near the telescopic mechanism are disconnected; a spring rod is located at the disconnection point between the first slide rod and the second slide rod; multiple first protrusions and multiple second protrusions, with the multiple first protrusions and second protrusions respectively located on the first... The slide rod and the other end of the second slide rod; two sets of swing rods, the two sets of swing rods being spaced apart between the first protrusion and the second protrusion and the first slide rod and the second slide rod; wherein the two ends of the swing rod are respectively hinged to the first protrusion and the first slide rod or the second protrusion and the second slide rod; a spring plate, the two ends of which are respectively connected to the first protrusion and the first slide rod or the second protrusion and the second slide rod; the first protrusion and the second protrusion each include a protrusion body, the protrusion body having a first inclined surface and a second inclined surface, the first inclined surface being located on the protrusion body near the motor housing in the direction of travel; the second inclined surface and the second inclined surface being located on the side of the protrusion body away from the slide rail sleeve; the first inclined surface cooperating with the end wall of the limiting sleeve assembly for the protrusion body to enter the limiting sleeve assembly; a mounting groove being formed adjacent to the first inclined surface and the second inclined surface; a steering wheel being installed in the mounting groove; a retaining ring being located on the end of the slide rail sleeve away from the telescopic mechanism.

[0016] In one possible implementation, the limiting sleeve assembly includes: a first sleeve, which covers the outer wall of the telescopic mechanism; a second sleeve, which is conical, with the smaller end of the conical second sleeve facing the direction of travel of the motor housing, and the larger end connected to one end of the first sleeve; and a third sleeve, which covers the outer wall of the slide rail sleeve, with one end of the third sleeve connected to the other end of the second sleeve, and the other end of the third sleeve disposed near the retaining ring.

[0017] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0018] When the series motor flexible connection device of the electric high-speed booster pump at the bottom of the oil and gas well is working, the transmission connection of the two sets of motor shafts is realized through the universal coupling. It allows a certain angle between the two shafts and reliably transmits torque and motion. The inner bellows is coaxially sleeved outside the universal coupling and maintains a distance, and the outer bellows is coaxially sleeved outside the inner bellows and maintains a distance. The two ends of the inner and outer bellows are fixed by the first connecting sleeve and the second connecting sleeve respectively. At the same time, the first connecting sleeve and the second connecting sleeve are connected to the housings of the two sets of motors. The inner and outer bellows adapt to the installation deviation or working condition deformation of the two motors without interfering with the angular displacement of the universal coupling, and at the same time form a double protection and buffer channel.

[0019] The inner and outer bellows form a double-sealed protective structure, which effectively prevents external dust, impurities, liquids and other substances from entering the universal coupling and motor shaft connection parts, reducing the risk of wear and corrosion and extending the service life of transmission components.

[0020] The flexible structure of the inner and outer bellows can work together to absorb the vibration and shock during motor operation, reduce fluctuations in torque transmission, reduce noise, and improve transmission smoothness.

[0021] The spacing between the inner and outer bellows and the universal coupling avoids mechanical interference between the bellows and the coupling when the bellows deforms, ensuring that the angular displacement compensation function of the universal coupling is not affected. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the flexible connection device for series motor of electric high-speed booster pump at the bottom of oil and gas well provided in the embodiments of this application;

[0024] Figure 2 This is a schematic diagram of motor installation provided in an embodiment of this application;

[0025] Figure 3 for Figure 2 Enlarged view of region A in the middle;

[0026] Figure 4 This is a schematic diagram of the connection structure provided in an embodiment of this application;

[0027] Figure 5 This is a schematic diagram of the motor power line positioning plate structure provided in an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of the obstacle avoidance device structure provided in the embodiments of this application;

[0029] Figure 7 for Figure 6 Enlarged view of region B in the middle;

[0030] Figure 8 This is a schematic diagram of the elastic obstacle avoidance unit structure provided in the embodiments of this application;

[0031] Figure 9 This is a schematic diagram of the installation of the first slide bar provided in an embodiment of this application;

[0032] Figure 10 This is a schematic diagram of the limiting sleeve assembly structure provided in an embodiment of this application.

[0033] icon:

[0034] 100-Universal Coupling;

[0035] 200-spindle;

[0036] 300-Motor;

[0037] 400-Inner corrugated pipe;

[0038] 500 - External corrugated pipe;

[0039] 600a - First connecting sleeve; 600b - Second connecting sleeve;

[0040] 610 - Connecting part;

[0041] 611-Ring body; 612-Motor power line through hole; 613-Motor shaft connection channel; 614-Prestressed hanging bolt; 615-Hanging hole; 616-Extension pipe;

[0042] 620 - Motor power line positioning plate; 621 - Auxiliary through hole;

[0043] 700 - Obstacle Avoidance Device;

[0044] 710 - Telescopic mechanism;

[0045] 711-First mounting ring; 712-Electric push rod; 713-Second mounting ring; 714-Guide ring; 715-Guide hole; 716-Drive rod;

[0046] 720 - Flexible obstacle avoidance unit;

[0047] 7211-Slide rail sleeve; 7212-Slide groove; 7213-First slide rod; 7214-Second slide rod; 7215-Transition sleeve; 7216-Third mounting ring; 7217-Spring rod; 7218-First protrusion; 7219-Second protrusion; 7220-Swing rod; 7221-Spring plate; 7222-Mounting groove; 7223-Steering wheel; 7224-Retaining ring;

[0048] 730 - Limit Sleeve Assembly;

[0049] 732 - First sleeve; 733 - Second sleeve; 734 - Third sleeve. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the description of the embodiments of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0052] Example 1

[0053] Please see Figures 1-5A flexible connection device for a series motor of a high-speed electric booster pump at the bottom of an oil and gas well includes: a universal coupling 100 disposed between the rotating shafts 200 of two sets of motors 300. The two ends of the universal coupling 100 are respectively connected to the ends of the rotating shafts 200 of the two sets of motors 300. The universal coupling 100 allows a certain angle between the two rotating shafts 200 and, under this angle condition, transmits the torque and motion of one rotating shaft 200 to the other rotating shaft 200. An inner bellows 400 is sleeved on the universal coupling 100, and the inner bellows 400 is coaxial with the universal coupling 100. The universal coupling 100 is configured with a spacing between them; an outer bellows 500 is coaxially sleeved around the outer periphery of the inner bellows 400 and has a spacing between them; a first connecting sleeve 600a and a second connecting sleeve 600b are respectively disposed at both ends of the universal coupling 100; wherein the two ends of the inner bellows 400 and the outer bellows 500 are respectively connected to the adjacent surfaces of the first connecting sleeve 600a and the second connecting sleeve 600b; the ends of the first connecting sleeve 600a and the second connecting sleeve 600b away from the outer bellows 500 are respectively connected to the housings of the two sets of motors 300.

[0054] In the above embodiments, when the flexible interface of the series motor 300 is working, the transmission connection of the two sets of motor 300 shafts 200 is realized through the universal coupling 100. It allows a certain angle between the two shafts 200 and reliably transmits torque and motion. The inner bellows 400 is coaxially sleeved outside the universal coupling 100 and maintains a distance. The outer bellows 500 is coaxially sleeved outside the inner bellows 400 and maintains a distance. The two ends of the inner and outer bellows 500 are fixed by the first connecting sleeve 600a and the second connecting sleeve 600b respectively. At the same time, the first connecting sleeve 600a and the second connecting sleeve 600b are connected to the housings of the two sets of motors 300. Without interfering with the angular displacement of the universal coupling 100, the inner and outer bellows 500 adapt to the installation deviation or working condition deformation of the two motors 300 and form a double protection and buffer channel.

[0055] The inner bellows 400 and the outer bellows 500 form a double-sealed protective structure, which effectively prevents external dust, impurities, liquids and other substances from entering the universal coupling 100 and the connection part 610 of the motor 300 shaft 200, reducing the risk of wear and corrosion and extending the service life of the transmission components.

[0056] The flexible structure of the inner and outer bellows 500 can work together to absorb the vibration and shock of the motor 300 during operation, reduce fluctuations in the torque transmission process, reduce noise, and improve transmission smoothness.

[0057] The spacing between the inner bellows 400 and the outer bellows 500 and the universal coupling 100 avoids mechanical interference between the bellows and the coupling when the bellows deforms, ensuring that the angular displacement compensation function of the universal coupling 100 is not affected.

[0058] Example 2

[0059] Please see Figures 1-5 Both the first connecting sleeve 600a and the second connecting sleeve 600b include a connecting portion 610. The connecting portion 610 includes an annular body 611, with an inner annular facet disposed on the outer circumferential surface of the universal coupling 100. The adjacent surfaces of the two sets of annular bodies 611 of the first connecting sleeve 600a and the second connecting sleeve 600b are respectively connected to the inner bellows 400 and the outer bellows 500. One end of the two sets of annular bodies 611 away from the inner bellows 400 and the outer bellows 500 extends into the housing of the motor 300 and contacts the inner wall of the housing of the motor 300.

[0060] In the above embodiment, the universal coupling 100 undertakes the core functions of angular displacement compensation and torque and motion transmission of the two motors 300 shafts 200. The rings 611 of the first connecting sleeve 600a and the second connecting sleeve 600b are set on the outer periphery of the universal coupling 100 through inner ring covers and spaced apart from the universal coupling 100, forming a protective base for the universal coupling 100. The adjacent surfaces of the two sets of rings 611 are fixedly connected to the two ends of the inner bellows 400 and the outer bellows 500, respectively, to realize the reliable assembly and positioning of the bellows, and to ensure that the inner bellows 400 and the outer bellows 500 are properly aligned. The bellows 500 and the universal coupling 100 maintain a coaxial distance. At the same time, the end of the ring 611 away from the bellows extends into the interior of the motor 300 housing and contacts the inner wall of the housing. The cooperation between the ring 611 and the inner wall of the housing achieves precise positioning of the connecting sleeve and the entire flexible interface relative to the motor 300 housing, ultimately forming an integrated transmission protection structure. This ensures that the universal coupling 100 can stably transmit power under the condition that the included angle between the two shafts is allowed. The inner and outer bellows 500 can adapt to flexible deformation with installation deviation or working condition deformation without interfering with the universal coupling 100.

[0061] Example 3

[0062] Please see Figures 1-5 Both sets of ring bodies 611 of the first connecting sleeve 600a and the second connecting sleeve 600b are provided with motor 300 power line through holes; the motor 300 power line through holes are provided through both sets of ring bodies 611; wherein the extension direction of the motor 300 power line through holes is parallel to the axis of the ring body 611; the cavity of the center of the ring body 611 is connected to the cavity of the center of the inner bellows 400 to form a motor 300 shaft connection channel; the adjacent ends of the rotating shafts 200 of the two sets of motors 300 and the universal coupling 100 are all provided in the motor 300 shaft connection channel.

[0063] In the above embodiments, when the series motor 300 flexible interface is working, the adjacent ends of the rotating shafts 200 of the two motors 300 and the universal coupling 100 are both housed in the motor 300 shaft connection channel formed by the center of the ring body 611 and the center of the inner bellows 400. The universal coupling 100 realizes angular displacement compensation and torque and motion stability transmission of the two rotating shafts 200 in the channel.

[0064] The ring body 611 of the first connecting sleeve 600a and the second connecting sleeve 600b is positioned on the outer periphery of the universal coupling 100 through the inner ring face cover and in contact with the inner wall of the motor 300 housing. The adjacent surfaces are fixed with inner and outer bellows 500 to form a double flexible protection structure.

[0065] Meanwhile, the motor 300 power line through hole opened on the ring 611 is arranged through the axial direction of the ring 611. The motor 300 power line can be arranged through the motor 300 power line through hole, which avoids the transmission components in the motor 300 shaft connection channel and does not interfere with the angular displacement of the universal coupling 100 and the flexible deformation of the inner and outer bellows 500.

[0066] The power line through-hole of motor 300 is set along the axis of ring 611 to achieve physical isolation of the power line from transmission components such as rotating shaft 200 and universal coupling 100. This avoids the power line from getting tangled, squeezed or worn due to the rotation and vibration of transmission components, reducing the risk of circuit failure. At the same time, it makes the overall wiring more organized and saves installation space.

[0067] Example 4

[0068] Please see Figures 1-5 The connecting part 610 further includes: at least one prestressed hanging bolt 614, with its two ends respectively connected to two sets of rings 611; and a hanging hole 615, extending in a direction parallel to the axis of the ring 611 and penetrating through the two sets of rings 611; wherein the prestressed hanging bolt 614 is disposed in the hanging hole 615; the diameter of the hanging hole 615 is larger than the screw diameter of the prestressed hanging bolt 614; and a plurality of prestressed hanging bolts 614 are arranged in a ring on the end face of the ring 611.

[0069] In the above embodiment, the two ends of the prestressed hanging bolt 614 are respectively connected to two sets of rings 611 and pass through the hanging hole 615 opened along the axial direction on the ring 611. The diameter of the hanging hole 615 is larger than the screw diameter of the prestressed hanging bolt 614. At the same time, multiple prestressed hanging bolts 614 are distributed in a ring on the end face of the ring 611.

[0070] During operation, the weight of the motor 300 itself and the counterweight force during descent will exert a downward pulling force on the inner bellows 400 and outer bellows 500 of the flexible series connection motor 300 interface. The upward dragging force during well lifting will also exert an upward pulling force on the inner bellows 400 and outer bellows 500.

[0071] At this time, the prestressed hanging bolt 614 directly bears the above-mentioned gravity and tensile force, forming a stable force-bearing whole between the two sets of rings 611, avoiding the tensile force from acting directly on the inner and outer bellows 500, thereby effectively preventing the inner and outer bellows 500 from undergoing excessive stretching deformation. At the same time, since the diameter of the hanging hole 615 is larger than the diameter of the screw, it will not interfere with the universal coupling 100, which allows the two rotating shafts 200 to have an included angle for angular displacement, ensuring that the original functions such as power transmission, protection, and wiring are normally realized.

[0072] Multiple prestressed hanging bolts 614 are distributed in a ring on the end face of the ring body 611, so that the force between the two sets of ring bodies 611 is evenly distributed, forming a stable force system. This avoids excessive local force, which may cause the connecting sleeve or the bellows connection part 610 to loosen or be damaged, and improves the structural stability of the entire flexible interface under complex downhole stress conditions.

[0073] Example 5

[0074] Please see Figures 1-5 The connecting part 610 further includes an extension tube 616, which is located at one end of the ring body 611 away from the inner corrugated tube 400 and the outer corrugated tube 500; wherein the inner wall of the extension tube 616 smoothly transitions with the inner wall of the ring body 611, and the motor 300 shaft connecting channel extends into the two sets of extension tubes 616.

[0075] In the above embodiment, the extension tube 616 is positioned in conjunction with the ring body 611 and the housing of the motor 300, which not only protects the end of the shaft 200, but also avoids interference with the rotation of the shaft 200 and the angular displacement of the universal coupling 100 due to the smooth transition of the inner wall. Furthermore, it prevents impurities such as dust and mud from entering the universal coupling 100 from the gap between the ring body 611 and the housing of the motor 300.

[0076] Example 6

[0077] Please see Figures 1-5 The second connecting sleeve 600b further includes: a motor 300 power line positioning plate, which is annular and located at the end of the extension tube 616 of the second connecting sleeve 600b away from the annular body 611; wherein the surface of the motor 300 power line positioning plate is provided with a plurality of auxiliary through holes 621 spaced apart, and the motor 300 power line passes through the auxiliary through holes 621 and enters the motor 300 power line through hole.

[0078] In the above embodiment, the motor 300 power line positioning plate is a ring structure, which is assembled at the end of the extension tube 616 of the second connecting sleeve 600b away from the ring body 611, and is located at the entrance position of the motor 300 power line entering the connecting sleeve.

[0079] Several auxiliary through holes 621 are opened at intervals on the surface of the positioning plate. Before entering the motor 300 power line through hole of the second connecting sleeve 600b, the motor 300 power line will pass through these auxiliary through holes 621 respectively to avoid multiple lines from getting tangled or crossing.

[0080] It can also limit the shaking and displacement of the line, keeping the power line in a neat routing posture, which not only facilitates quick alignment and threading during assembly, but also reduces wear caused by friction and pulling of the line during subsequent use, thereby achieving a stable auxiliary positioning effect for the 300 power line of the motor.

[0081] Example 7

[0082] Please see Figures 6-10 The motor 300 is further fitted with an obstacle avoidance device 700, which includes: a telescopic mechanism 710 and an elastic obstacle avoidance unit 720; wherein the telescopic mechanism 710 is installed on the circumferential outer wall of the motor 300's housing, and its extended end is connected to the elastic obstacle avoidance unit 720; a limiting sleeve assembly 730 is fitted over the outer wall of the telescopic mechanism 710, and the telescopic mechanism 710 is used to drive the elastic obstacle avoidance unit 720 to slide within the limiting sleeve assembly 730; the elastic obstacle avoidance unit 720 moves toward the housing of the motor 300 as it enters the limiting sleeve assembly 730.

[0083] In the above embodiment, the shafts 200 of multiple downhole motors 300 are spliced ​​together through flexible interfaces to form a long shaft structure. The flexible structure allows adjacent shafts 200 to form a certain angle when moving within the shaft to adapt to the shaft's orientation. Due to the long shaft length and rough inner wall, protruding obstacles are prone to occur. When the motor 300 drives the spliced ​​shafts 200 to encounter obstacles while moving within the shaft, the obstacle avoidance device 700, which is fitted onto the outer casing of the motor 300, is activated: the telescopic mechanism 710, installed on the circumferential outer wall of the motor 300's outer casing, retracts, and its extended end drives the connected elastic obstacle avoidance unit 720 to move synchronously. The limiting sleeve assembly 730 is installed on the outer wall of the telescopic mechanism 710 to provide sliding guidance for the elastic obstacle avoidance unit 720. Since the initial outer diameter of the elastic obstacle avoidance unit 720 is larger than the inner diameter of the limiting sleeve assembly 730, during the process of the telescopic mechanism 710 dragging the elastic obstacle avoidance unit 720 into the limiting sleeve assembly 730, the limiting sleeve assembly 730 forms a circumferential block on the elastic obstacle avoidance unit 720, restricting its radial expansion, thereby forcing the elastic obstacle avoidance unit 720 to move closer to the motor 300 housing, realizing the contraction of the overall outer diameter of the obstacle avoidance device 700, and ensuring that the device can smoothly pass through the obstacle area.

[0084] From the perspective of construction support, the synergistic effect of the telescopic mechanism 710, the elastic obstacle avoidance unit 720 and the limiting sleeve assembly 730 effectively solves the obstacle avoidance problem of long-axis splicing structure in long-distance, non-smooth wells, avoids construction stagnation due to obstacles, and ensures that the motor 300 and splicing shaft 200 can be pushed forward stably.

[0085] From the perspective of equipment protection, the obstacle avoidance device 700 can serve as an isolation and protection structure between the motor 300 housing and the inner wall of the well, preventing the motor 300 housing from directly rubbing or colliding with the inner wall of the well. This not only prevents the problem of excessive friction causing the motor 300 housing to be unable to move normally, but also avoids the risk of the well protrusion scratching the motor 300 housing, fundamentally reducing the impact of housing damage on the service life of the motor 300, and adapting to the needs of complex and harsh downhole construction environments.

[0086] Example 8

[0087] Please see Figures 6-10 The telescopic mechanism 710 includes: a first mounting ring 711, sleeved on the circumferential outer wall of the housing of the motor 300; multiple electric push rods 712, with one end of each electric push rod 712 spaced apart on one side of the first mounting ring 711; a second mounting ring 713, coaxial with the first mounting ring 711 and located at the other end of the multiple electric push rods 712; a guide ring 714, coaxial with the second mounting ring 713 and spaced apart on the side of the second mounting ring 713 away from the first mounting ring 711; wherein the guide ring 714 has a plurality of guide holes 715 spaced apart on its circumferential outer wall; and multiple drive rods 716, with one end spaced apart on the side of the second mounting ring 713 away from the electric push rods 712; each drive rod 716 passes through the guide hole 715 and is connected to the elastic obstacle avoidance unit 720.

[0088] In the above embodiment, the first mounting ring 711 of the telescopic mechanism 710 is sleeved and fixed to the circumferential outer wall of the motor 300 housing, providing an installation reference for the entire telescopic mechanism 710. When the motor 300 drives the splicing shaft 200 to move in the well and encounters a protruding obstacle, multiple electric push rods 712 spaced apart on one side of the first mounting ring 711 synchronously initiate a retraction action, driving the second mounting ring 713 connected to its other end to move along the axial direction of the motor 300. The guide rings 714, which are coaxially spaced with the second mounting ring 713, play a guiding and limiting role. The guide holes 715 spaced apart on the second mounting ring 714 provide a precise sliding channel for the drive rod 716, which moves along with the second mounting ring. Multiple drive rods 716, which move 713, have one end fixed to the side of the second mounting ring 713 away from the electric push rod 712, and the other end passes through the guide hole 715 and is firmly connected to the elastic obstacle avoidance unit 720. Under the constraint of the guide hole 715, the elastic obstacle avoidance unit 720 moves smoothly. Combined with the function of the limiting sleeve assembly 730, since the initial outer diameter of the elastic obstacle avoidance unit 720 is larger than the inner diameter of the limiting sleeve assembly 730, it is circumferentially blocked by the limiting sleeve assembly 730 and moves towards the direction of the motor 300 housing when it enters the limiting sleeve assembly 730 under the drive of the drive rod 716. This achieves the contraction of the outer diameter of the obstacle avoidance device 700 and ensures that the whole device passes through the obstacle area smoothly.

[0089] The obstacle avoidance stability and structural reliability are improved. The multiple electric push rods 712 are evenly spaced to ensure the force balance of the second mounting ring 713 and avoid the movement deviation caused by unilateral force. The cooperation structure between the guide ring 714 and the drive rod 716 can accurately constrain the movement trajectory of the drive rod 716, ensuring that the elastic obstacle avoidance unit 720 moves smoothly along the axis and preventing it from tilting or jamming during movement, thus improving the accuracy and smoothness of the obstacle avoidance action.

[0090] The coordinated operation of all parts of the telescopic mechanism 710 makes the telescopic power transmission more stable and efficient, adapting to the complex and harsh working conditions downhole. At the same time, the obstacle avoidance device 700 can still isolate the motor 300 housing from the inner wall of the well, avoiding direct friction and collision, preventing scratches on the motor 300 housing and movement jamming, ensuring the stable advancement of the long shaft splicing structure, ensuring construction continuity, and extending the service life of the motor 300.

[0091] Example 9

[0092] Please see Figures 6-10The elastic obstacle avoidance unit 720 includes: a slide rail sleeve 7211, spaced apart on the side of the second mounting ring 713 away from the first mounting ring 711, and fixedly sleeved on the circumferential outer wall of the motor 300 housing; multiple slide grooves 7212, spaced apart on the circumferential outer wall of the slide rail sleeve 7211, and parallel to the axis of the slide rail sleeve 7211; multiple first slide rods 7213 and second slide rods 7214, each alternately arranged in each slide groove 7212; and a transition sleeve 7215, slidably sleeved on the circumferential outer wall of the motor 300 housing. One end of the second slide rod 7214 is connected to the guide ring 714, and the other end is connected to a plurality of first slide rods 7213; a third mounting ring 7216 is slidably sleeved on the outer circumferential wall of the transition sleeve 7215, and one end of the plurality of second slide rods 7214 is connected to the side wall of the third mounting ring 7216; the first slide rod 7213 and the second slide rod 7214 are disconnected at the ends near the telescopic mechanism 710; a spring rod 7217 is provided at the disconnection point between the first slide rod 7213 and the second slide rod 7214; a plurality of first protrusions 7218 and second protrusions 7219 are provided respectively, and the plurality of first protrusions 7218 and second protrusions 7219 are respectively provided on the first slide rod 7215. 213 and the other end of the second slide rod 7214; a rocker arm 7220, provided in two sets, the two sets of rocker arms 7220 being spaced apart between the first protrusion 7218 and the second protrusion 7219 and the first slide rod 7213 and the second slide rod 7214; wherein the two ends of the rocker arm 7220 are respectively hinged to the first protrusion 7218 and the first slide rod 7213 or the second protrusion 7219 and the second slide rod 7214; a spring plate 7221, the two ends of which are respectively connected to the first protrusion 7218 and the first slide rod 7213 or the second protrusion 7219 and the second slide rod 7214; the first protrusion 7218 and the other end of the second slide rod 7214; the first protrusion 7218 and the second slide rod 7214; the first protrusion 7218 and the second slide rod 7214; the second slide rod 7214 ... Each of the second protrusions 7219 includes a protrusion body, the protrusion body having a first inclined surface and a second inclined surface. The first inclined surface is located on the protrusion body near the outer casing of the motor 300 in the direction of travel. The second inclined surface is located on the side of the protrusion body away from the slide rail sleeve 7211. The first inclined surface cooperates with the end wall of the limiting sleeve assembly 730 for the protrusion body to enter the limiting sleeve assembly 730. A mounting groove 7222 is formed at the position adjacent to the first inclined surface and the second inclined surface. A steering wheel 7223 is installed in the mounting groove 7222. A retaining ring 7224 is located at the end of the slide rail sleeve 7211 away from the telescopic mechanism 710.

[0093] In the above embodiment, the slide rail sleeve 7211 is fixedly sleeved on the peripheral wall of the motor 300 housing. The parallel slide groove 7212 opened on its outer wall provides stable guidance for the first slide rod 7213 and the second slide rod 7214. The first slide rod 7213 and the second slide rod 7214 are alternately embedded in each slide groove 7212. When the device encounters an obstacle in the well, the telescopic mechanism 710 drives the transition sleeve 7215 to move axially along the housing of the motor 300. One end of the transition sleeve 7215 is connected to the guide ring 714, and the other end is fixedly connected to multiple first slide rods 7213, thereby synchronously driving the first slide rods 7213 to slide smoothly along the slide groove 7212. The third mounting ring 7216 is slidably sleeved on the outer peripheral wall of the transition sleeve 7215. One end of multiple second slide rods 7214 is fixedly connected to the side wall of the third mounting ring 7216, and moves synchronously with the third mounting ring 7216. The second slide rod 7214 slides along the slide groove 7212. The ends of the first slide rod 7213 and the second slide rod 7214 near the telescopic mechanism 710 are disconnected. A spring rod 7217 installed at the disconnection point enables flexible linkage between the two slide rods. The first inclined surface on the protrusion body of the first protrusion 7218 and the second protrusion 7219 precisely matches the end wall of the limiting sleeve assembly 730, guiding the first protrusion 7218 and the second protrusion 7219 smoothly into the limiting sleeve assembly 730. The mounting groove 7222 on the protrusion body... The internally installed steering wheel 7223 can significantly reduce the frictional resistance during the process of the first protrusion 7218 and the second protrusion 7219 entering the sleeve; the two ends of the rocker arm 7220 are respectively hinged to the first protrusion 7218 and the first slide rod 7213, and the two ends of the second protrusion 7219 and the second slide rod 7214; the two ends of the spring plate 7221 are also respectively connected to the first protrusion 7218 and the first slide rod 7213, and the second protrusion 7219 and the second slide rod 7214. The rocker arm 7220 and the spring plate 7221 cooperate with each other to realize the first protrusion 7218 and the second protrusion 7219 entering the sleeve. The adaptive swing adjustment of 7219 and the second inclined plane adapt to the complex well environment downhole. The retaining ring 7224 set at the end of the slide rail sleeve 7211 away from the telescopic mechanism 710 can effectively limit the sliding stroke of the first slide rod 7213 and the second slide rod 7214 and prevent them from disengaging from the slide rail sleeve 7211. During the whole process, under the driving action of the telescopic mechanism 710 and the constraint action of the limiting sleeve assembly 730, the elastic obstacle avoidance unit 720 moves towards the outer shell of the motor 300 and finally completes the overall outer diameter contraction to achieve obstacle avoidance.

[0094] The rudder wheel 7223, together with the first and second inclined surfaces, forms a double-inclined structure that significantly reduces the frictional resistance of the first protrusion 7218 and the second protrusion 7219 as they enter the limiting sleeve assembly 730 and when they come into contact with obstacles in the shaft. This effectively avoids jamming during obstacle avoidance and allows the structure to adapt to more complex shaft protrusion environments. Secondly, the elastic linkage design formed by the swing rod 7220, spring plate 7221, and spring rod 7217 gives the first protrusion 7218 and the second protrusion 7219 flexible adaptive adjustment capabilities, which can effectively buffer the impact force generated when in contact with obstacles and reduce hard wear between components. Thirdly, the limiting function of the retaining ring 7224 further enhances the structural stability of the elastic obstacle avoidance unit 720, preventing the first slide rod 7213 and the second slide rod 7214 from misaligning or detaching from the slide rail sleeve 7211 during sliding.

[0095] Meanwhile, the optimized flexible obstacle avoidance unit 720 further enhances the isolation and protection effect between the outer shell of the motor 300 and the inner wall of the well, ensuring that the long shaft structure formed by splicing multiple motors 300 through flexible interfaces can be smoothly advanced. This not only significantly improves the continuity and reliability of downhole construction, but also effectively extends the service life of the entire device and the motor 300.

[0096] Example 10

[0097] Please see Figures 6-10 The limiting sleeve assembly 730 includes: a first sleeve 732, which covers the outer wall of the telescopic mechanism 710; a second sleeve 733, which is conical, with the smaller end of the conical second sleeve 733 facing the direction of travel of the outer casing of the motor 300, and the larger end connected to one end of the first sleeve 732; and a third sleeve 734, which covers the outer wall of the slide rail sleeve 7211, with one end of the third sleeve 734 connected to the other end of the second sleeve 733, and the other end of the third sleeve 734 disposed near the retaining ring 7224.

[0098] In the above embodiment, the first sleeve 732 is fitted onto the outer wall of the telescopic mechanism 710. The conical second sleeve 733 has its small end facing the direction of travel of the motor 300 and its large end connected to the first sleeve 732. The third sleeve 734 is fitted onto the outer wall of the slide rail sleeve 7211, with one end connected to the second sleeve 733 and the other end close to the retaining ring 7224 and cooperating with the first protrusion 7218 and the second protrusion 7219. When encountering an obstacle, the electric push rod 712 pulls the third mounting ring 7216, which first moves the second protrusion 7219. After the third mounting ring 7216 abuts against the limiting sleeve, it pushes the limiting sleeve to move, causing the second protrusion 7219 to separate from the first protrusion 7218 and leaving a movement distance for the first protrusion 7218. Then, the first protrusion 7218 can be moved, cooperating with the elastic obstacle avoidance unit 720 to move towards the outer diameter of the motor 300 housing to achieve outer diameter contraction.

[0099] The conical second sleeve 733 guides the device to smoothly cut into the obstacle area, reducing travel resistance; the cooperation between the third sleeve 734 and the protrusion and the step-by-step movement design of the protrusion avoids the linkage interference of the protrusion, improves the accuracy of the retraction action, and adapts to complex well obstacle; at the same time, it enhances the coordinated stability of the limiting sleeve assembly 730 and the elastic obstacle avoidance unit 720, further ensuring the smooth advancement of the long shaft structure, continuing the isolation and protection effect of the motor 300 housing, and improving construction reliability and equipment service life.

[0100] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0101] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A flexible connection device for a series motor of an electric high-speed booster pump at the bottom of an oil and gas well, comprising: A universal coupling (100) is disposed between the rotating shafts (200) of two sets of motors (300). The two ends of the universal coupling (100) are respectively connected to the ends of the rotating shafts (200) of the two sets of motors (300). The universal coupling (100) is used to allow a certain angle between the two rotating shafts (200) and to transmit the torque and motion of one rotating shaft (200) to the other rotating shaft (200) under the angle condition. The universal coupling (100) is characterized in that an inner bellows (400) is provided on the outer sleeve of the universal coupling (100). The inner bellows (400) is coaxially arranged with the universal coupling (100) and has a gap. The outer corrugated pipe (500) is coaxially sleeved on the outer periphery of the inner corrugated pipe (400) and has a gap with the inner corrugated pipe (400); The first connecting sleeve (600a) and the second connecting sleeve (600b) are respectively disposed at both ends of the universal coupling (100); wherein The inner corrugated pipe (400) and the outer corrugated pipe (500) are respectively connected to the adjacent surfaces of the first connecting sleeve (600a) and the second connecting sleeve (600b); The ends of the first connecting sleeve (600a) and the second connecting sleeve (600b) away from the outer bellows (500) are respectively connected to the housings of the two sets of motors (300); Both the first connecting sleeve (600a) and the second connecting sleeve (600b) include a connecting portion (610), the connecting portion (610) comprising: The ring body (611) has an inner ring faceplate disposed on the outer circumferential surface of the universal coupling (100); wherein The two sets of rings (611) of the first connecting sleeve (600a) and the second connecting sleeve (600b) are respectively connected to the inner bellows (400) and the outer bellows (500). The two sets of ring bodies (611) extend away from the inner bellows (400) and the outer bellows (500) into the housing of the motor (300) and are in contact with the inner wall of the housing of the motor (300); both sets of ring bodies (611) of the first connecting sleeve (600a) and the second connecting sleeve (600b) are provided with through holes for the power line of the motor (300); The power line of the motor (300) is provided through holes that pass through both sets of the ring bodies (611); wherein The extension direction of the motor (300) power line through hole is parallel to the axis of the ring (611); The cavity at the center of the ring (611) is connected to the cavity at the center of the inner bellows (400) to form a shaft connection channel for the motor (300); The adjacent ends of the shafts (200) of the two sets of motors (300) and the universal coupling (100) are all located within the shaft connection channel of the motors (300); the connecting part (610) further includes: At least one prestressed hanging bolt (614) is connected at both ends to two sets of the rings (611); and The hanging hole (615) extends parallel to the axis of the ring (611) and passes through both sets of rings (611); wherein The prestressed hanging bolt (614) is located inside the hanging hole (615); The diameter of the hanging hole (615) is larger than the diameter of the prestressed hanging bolt (614); Multiple prestressed hanging bolts (614) are arranged in a ring on the end face of the ring body (611).

2. The series-connected flexible connection device for the electric high-speed booster pump at the bottom of an oil and gas well according to claim 1, characterized in that, The connecting part (610) further includes: An extension tube (616) is disposed at one end of the ring body (611) away from the inner bellows (400) and the outer bellows (500); wherein The inner wall of the extension tube (616) smoothly transitions with the inner wall of the ring (611), and the motor (300) shaft connection channel extends into the two sets of extension tubes (616).

3. The flexible connection device for series motor of the oil and gas well bottom electric high-speed booster pump according to claim 2, characterized in that, The second connecting sleeve (600b) also includes: The motor (300) power line positioning plate is annular and is located at the end of the extension tube (616) of the second connecting sleeve (600b) away from the annular body (611); wherein The surface of the motor (300) power line positioning plate is provided with a plurality of auxiliary through holes (621) spaced apart. The motor (300) power line passes through the auxiliary through holes (621) and enters the motor (300) power line through hole.

4. The series-connected flexible connection device for the electric high-speed booster pump at the bottom of an oil and gas well according to claim 3, characterized in that, An obstacle avoidance device (700) is also fitted onto the housing of the motor (300), the obstacle avoidance device (700) comprising: Telescopic mechanism (710), elastic obstacle avoidance unit (720); wherein The telescopic mechanism (710) is installed on the circumferential outer wall of the housing of the motor (300), and the top end is connected to the elastic obstacle avoidance unit (720); A limiting sleeve assembly (730) is fitted over the outer wall of the telescopic mechanism (710), and the telescopic mechanism (710) is used to drive the elastic obstacle avoidance unit (720) to slide within the limiting sleeve assembly (730); As the elastic obstacle avoidance unit (720) enters the limiting sleeve assembly (730), it moves toward the housing of the motor (300).

5. The series-connected flexible connection device for the electric high-speed booster pump at the bottom of an oil and gas well according to claim 4, characterized in that, The telescopic mechanism (710) includes: The first mounting ring (711) is sleeved on the circumferential outer wall of the outer casing of the motor (300); Multiple electric push rods (712) are provided, with one end of each electric push rod (712) spaced apart on one side of the first mounting ring (711); The second mounting ring (713) is coaxial with the first mounting ring (711) and is located at the other end of the plurality of electric push rods (712); A guide ring (714) is coaxial with the second mounting ring (713) and spaced apart on the side of the second mounting ring (713) away from the first mounting ring (711); wherein The guide ring (714) has a plurality of guide holes (715) spaced apart on its circumferential outer wall. The drive rod (716) is provided in multiple positions, with one end spaced apart on the side of the second mounting ring (713) away from the electric push rod (712); Each of the drive rods (716) passes through the guide hole (715) and is connected to the elastic obstacle avoidance unit (720).

6. The series-connected flexible connection device for the electric high-speed booster pump at the bottom of an oil and gas well according to claim 5, characterized in that, The elastic obstacle avoidance unit (720) includes: The slide rail sleeve (7211) is spaced apart on the side of the second mounting ring (713) away from the first mounting ring (711) and is fixedly sleeved on the circumferential outer wall of the outer shell of the motor (300); Multiple slide grooves (7212) are provided, and the multiple slide grooves (7212) are spaced apart on the outer circumferential wall of the slide rail sleeve (7211) and are respectively parallel to the axis of the slide rail sleeve (7211); Multiple first slide rods (7213) and multiple second slide rods (7214) are provided, and multiple first slide rods (7213) and multiple second slide rods (7214) are alternately arranged in each of the slide grooves (7212); The transition sleeve (7215) is slidably sleeved on the outer circumferential wall of the outer casing of the motor (300), and one end is connected to the guide ring (714), and the other end is connected to a plurality of the first slide rods (7213). The third mounting ring (7216) is slidably sleeved on the outer circumferential wall of the transition sleeve (7215), and one end of the plurality of second sliding rods (7214) is connected to the side wall of the third mounting ring (7216); The first slide bar (7213) and the second slide bar (7214) are disconnected at one end near the telescopic mechanism (710); A spring rod (7217) is provided at the break between the first slide rod (7213) and the second slide rod (7214); Multiple first protrusions (7218) and multiple second protrusions (7219) are provided, and multiple first protrusions (7218) and multiple second protrusions (7219) are respectively provided at the other end of the first slide rod (7213) and the second slide rod (7214); The rocker arm (7220) is provided in two sets, with the two sets of rocker arms (7220) spaced apart between the first protrusion (7218) and the second protrusion (7219) and the first slide rod (7213) and the second slide rod (7214); wherein The two ends of the swing arm (7220) are respectively hinged to the first protrusion (7218) and the first slide rod (7213) or the second protrusion (7219) and the second slide rod (7214). The spring sheet (7221) is connected at both ends to the first protrusion (7218) and the first slide rod (7213) or the second protrusion (7219) and the second slide rod (7214). Both the first protrusion (7218) and the second protrusion (7219) include a protrusion body, the protrusion body having a first inclined surface and a second inclined surface, the first inclined surface being disposed on the protrusion body near the outer casing of the motor (300) in the direction of travel; The second inclined surface is located on the side of the protrusion body away from the slide rail sleeve (7211); The first inclined surface cooperates with the end wall of the limiting sleeve assembly (730) for the protrusion body to enter the limiting sleeve assembly (730); The mounting groove (7222) is provided at the junction of the first inclined surface and the second inclined surface; The steering wheel (7223) is installed in the mounting slot (7222); A retaining ring (7224) is provided at the end of the slide rail sleeve (7211) away from the telescopic mechanism (710).

7. The series motor flexible connection device for the bottom-hole electric high-speed booster pump of an oil and gas well according to claim 6, characterized in that, The limiting sleeve assembly (730) includes: The first sleeve (732) is fitted over the outer wall of the telescopic mechanism (710); The second sleeve (733) is conical, with the small end of the conical second sleeve (733) facing the direction of travel of the outer casing of the motor (300), and the large end connected to one end of the first sleeve (732); The third sleeve (734) is covered on the outer wall of the slide rail sleeve (7211). One end of the third sleeve (734) is connected to the other end of the second sleeve (733), and the other end of the third sleeve (734) is located near the retaining ring (7224).

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