Submersible pump for preventing bearing electric corrosion

Abstract

The application discloses a submersible pump capable of preventing bearing electric corrosion, which comprises a pump body, a motor and a connecting assembly. The motor is provided with a rotor shaft, the pump body is provided with a water pump shaft, the connecting assembly connects the rotor shaft and the water pump shaft, the bottom of the motor is provided with a lower bearing seat, the lower bearing seat is provided with a lower bearing chamber for accommodating a lower bearing, an insulating bushing is fixedly connected in the lower bearing chamber, the lower bearing is fixedly connected in the insulating bushing, and the end of the rotor shaft close to the lower bearing seat is connected with the lower bearing. The insulating bushing is arranged between the lower bearing and the lower bearing chamber, so that the common-mode shaft current is blocked from releasing differential pressure GND current on the lower bearing, the bearing is restored to the pure bearing rotating mechanical property, and the service life is prolonged under the normal technical parameter allowable condition.

Description

Technical Field

[0001] This invention belongs to the field of submersible pump technology, and specifically relates to a submersible pump that prevents bearing electro-corrosion. Background Technology

[0002] Submersible pumps, as core equipment for underwater fluid transport, are widely used in deep well water intake, water supply and drainage, farmland irrigation, and industrial water circulation. A typical vertical multistage submersible pump mainly consists of three modules: a motor, a connecting frame, and a multistage pump body. The motor drives the pump shaft within the pump body to rotate synchronously via the connecting structure. The water pressure is gradually increased by alternating impellers and guide vanes on the pump shaft, ultimately completing the water transport operation. Among these, permanent magnet synchronous motors, with their advantages of high efficiency, energy saving, and high power density, have gradually replaced traditional asynchronous motors as the mainstream drive component for submersible pumps. However, during long-term underwater operation, submersible pumps equipped with permanent magnet motors exhibit a critical defect: the bearings are prone to electrolytic corrosion, which limits the equipment's service life.

[0003] During the operation of a permanent magnet motor, a common-mode voltage is generated due to the voltage difference between the three-phase windings and the harmonic voltage difference. This voltage needs to be balanced and discharged through a conductive path. The discharge current is conducted along the rotor shaft to each groundable conductive component. The complete current path is, in sequence, the rotor shaft, the lower bearing, the lower bearing housing, the motor housing, and finally to the ground. The lower bearing is assembled inside the lower bearing housing. Under operating conditions, it not only needs to withstand an axial pressure load of no less than 1400N, but also needs to continuously bear the conduction of the discharge current. The bearing is subjected to large axial pressure and conductive current simultaneously for a long time, which can easily induce bearing electro-corrosion. After the bearing corrodes, the rotational friction torque continues to increase, and the motor operating current increases accordingly. The electro-corrosion damage and load loss superimpose each other, creating a vicious cycle that continuously damages the rolling fit structure of the bearing, significantly shortening the service life of the permanent magnet motor and even the entire submersible pump, and significantly increasing the equipment maintenance and replacement costs. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems existing in the prior art and to provide a submersible pump that prevents bearing electro-corrosion. By adding a bushing between the lower bearing and the lower bearing chamber, the common mode shaft current is blocked from releasing the differential pressure to ground (GND) current on the lower bearing, restoring the bearing's pure load-bearing rotating mechanical properties and extending its service life under normal technical parameters.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A submersible pump for preventing bearing electro-corrosion includes a pump body, a motor, and a connecting assembly. The motor has a rotor shaft, and the pump body has a water pump shaft. The connecting assembly connects the rotor shaft and the water pump shaft. A lower bearing housing is located at the bottom of the motor, and a lower bearing chamber is located within the lower bearing housing to accommodate the lower bearing. A bushing is fixedly connected within the lower bearing chamber, and the lower bearing is fixedly connected within the bushing. The end of the rotor shaft near the lower bearing housing is connected to the lower bearing. This invention, by adding a bushing between the lower bearing and the lower bearing chamber, utilizes the insulating isolation effect of the bushing to cut off the conductive path from the rotor shaft, lower bearing, lower bearing housing, and motor housing to the ground. This blocks the shaft current generated by the three-phase voltage difference and harmonic common-mode voltage during permanent magnet motor operation from being discharged to ground through the lower bearing, eliminating bearing electro-corrosion. The lower bearing only bears the axial mechanical load from equipment operation, restoring the bearing's simple rotational mechanical working property, avoiding the vicious cycle of increased frictional torque and increased motor operating current caused by bearing corrosion, significantly extending the service life of the bearing and the entire motor, and reducing equipment maintenance and replacement costs.

[0006] Furthermore, the motor includes a housing, a stator, a rotor shaft, an upper bearing housing, and a lower bearing housing. The stator and rotor shaft are both located inside the housing. The upper bearing housing and the lower bearing housing are located at both ends of the rotor shaft. The upper bearing housing is fixedly connected to one end of the housing, and the lower bearing housing is located inside the housing. An upper bearing is provided between the rotor shaft and the upper bearing housing, and a lower bearing is provided between the rotor shaft and the lower bearing housing.

[0007] Furthermore, a pressure regulating diaphragm is provided at the end of the housing located in the lower bearing seat to regulate the internal pressure of the motor.

[0008] Furthermore, the pressure regulating diaphragm is made of rubber and has an axial cross-section in the shape of an inverted triangle.

[0009] Furthermore, a barrier protrudes inside the lower bearing housing to form a lower bearing chamber, the end of the barrier protrudes upward to form a limiting part, and an annular positioning groove is recessed inside the lower bearing chamber.

[0010] Furthermore, one end of the bushing is provided with a positioning part, which is matched with an annular positioning groove, and the other end of the bushing is provided with a wrapping ring, with an annular protrusion inside the wrapping ring; When the bushing is fixed to the lower bearing housing, the positioning part is inserted into the annular positioning groove, the wrapping ring wraps around the limiting part, and the annular protrusion abuts against the limiting part, so that the bushing covers the inner wall of the lower bearing housing.

[0011] Furthermore, the bushing is integrally molded from insulating material; the insulating material may be, for example, nylon 66 material with 30% glass fiber added.

[0012] Furthermore, the connecting assembly includes a connecting frame and a connecting shaft. One end of the connecting shaft is circumferentially fixed and axially movable relative to the rotor shaft. The other end of the connecting shaft is drively connected to the water pump shaft. The rotor shaft drives the water pump shaft to rotate through the connecting shaft. One end of the connecting frame is fixedly connected to the motor end, and the other end of the connecting frame is fixedly connected to the pump body. The connecting frame has a cavity inside, and the connecting shaft is located in the cavity. The upper and lower ends of the connecting frame are open. Water inlet holes are distributed circumferentially on the outer side wall of the connecting frame and are connected to the cavity. The rotor shaft is provided with a spline at the end corresponding to the connecting frame, and a keyway hole is provided at the end corresponding to the connecting shaft. The end of the rotor shaft is inserted into the keyway hole.

[0013] Furthermore, the pump body includes a pump casing, a flow guiding component, and an outlet end cover. The pump casing adopts a hollow structure with openings at both ends. One end of the pump casing is fixedly connected to the connecting component, and the other end of the pump casing is connected to the outlet end cover. The outlet end cover is provided with an outlet hole. The flow guiding component is located inside the pump casing to control the entry of external water into the pump casing and guide it to the outlet end cover, and then deliver the water through the outlet hole.

[0014] Furthermore, the flow guiding assembly includes several guide vanes and several impellers. The guide vanes and impellers are fixedly connected to the pump shaft. An impeller is installed at one end of the pump casing near the connecting frame, and a guide vane is installed at one end of the pump casing near the outlet end cover. The impellers and guide vanes are arranged alternately and evenly along the pump shaft axis, and a retaining ring is provided between adjacent impellers and guide vanes.

[0015] The present invention, by adopting the above-described technical solution, has the following beneficial effects: This invention eliminates the problem of bearing electro-corrosion at its source by installing a bushing between the lower bearing and its housing, thus isolating the conductive path between the outer ring of the lower bearing and the metal housing. This cuts off the shaft current discharge circuit formed by the three-phase voltage difference and harmonic common-mode voltage of the permanent magnet motor. The lower bearing then bears only the axial mechanical load, avoiding the vicious cycle of increased frictional torque and motor operating current caused by bearing corrosion. This effectively extends the service life of the bearing and the entire motor, reducing equipment maintenance and replacement costs.

[0016] This invention features a multi-limiting structure combined with high-strength insulating material to ensure long-term stable insulation performance. The lower bearing housing's enclosure, annular positioning groove, limiting part, bushing positioning part, wrapping ring, and annular protrusion engage and lock with each other, achieving seamless shielding of the bearing inner wall by the bushing, preventing slippage and loosening during operation. The bushing is integrally molded from materials such as 30% glass fiber reinforced nylon 66, possessing both insulation performance and compressive and creep resistance, capable of withstanding high axial loads for extended periods, and not easily deformed or damaged under high temperature and vibration environments, continuously maintaining the integrity of the insulation barrier.

[0017] This invention optimizes the motor support, pressure regulation, transmission connection, and pump body flow guiding structure, reducing mechanical losses in the bushing and lower bearing from multiple dimensions. Dual bearings at both ends of the rotor shaft evenly distribute the load, and a pressure regulating diaphragm balances the water pressure inside and outside the motor cavity to prevent stress compression. Alternating multi-stage impeller guide vanes, combined with retaining rings for rectification and vibration reduction, significantly weaken the transmission of alternating water flow vibrations to the motor bearings, aiding in the protection of the insulation structure, and simultaneously improving the pump's hydraulic delivery efficiency. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of a submersible pump for preventing bearing electro-corrosion according to the present invention; Figure 2 This is a schematic diagram of the structure of the motor in this invention; Figure 3 for Figure 2 Cross-sectional view of AA in the middle; Figure 4 This is a schematic diagram of the connection between the lower bearing housing and the bushing in this invention; Figure 5 for Figure 4 Cross-sectional view of BB in the middle; Figure 6 This is a schematic diagram of the structure of the lower bearing housing in this invention; Figure 7 This is a schematic diagram of the bushing connection in the present invention; Figure 8 for Figure 7 Cross-sectional view of CC in China; Figure 9 This is a schematic diagram of the structure of the separator strip in this invention; Figure 9 This is a schematic diagram of the connecting frame in this invention; Figure 10 This is a schematic diagram of the connecting shaft in this invention; Figure 11 for Figure 10 Cross-sectional view of DD in the middle; Figure 12 This is a schematic diagram of the pump body in this invention; Figure 13 for Figure 12 Cross-sectional view of EE.

[0019] In the diagram, 1-pump body; 2-motor; 3-connecting assembly; 4-rotor shaft; 5-pump shaft; 6-lower bearing housing; 7-lower bearing chamber; 8-lower bearing; 9-bulb; 10-casing; 11-stator; 12-outlet end cover; 13-upper bearing housing; 14-outlet hole; 15-upper bearing; 16-pressure regulating diaphragm; 17-enclosure; 18-limiting part; 19-annular positioning groove; 20-positioning part; 21-wrapping ring; 22-annular protrusion; 23-connecting frame; 24-connecting shaft; 25-inlet hole; 26-spline; 27-keyway hole; 28-pump casing; 29-guide assembly; 30-guide vane; 31-impeller; 32-retaining ring. Detailed Implementation

[0020] like Figures 1 to 13 As shown, this invention provides a submersible pump for preventing bearing electro-corrosion, comprising a pump body 1, a motor 2, and a connecting assembly 3. The motor 2 is provided with a rotor shaft 4, and the pump body 1 is provided with a water pump shaft 5. The connecting assembly 3 connects the rotor shaft 4 and the water pump shaft 5. The bottom of the motor 2 is provided with a lower bearing seat 6, and the lower bearing seat 6 is provided with a lower bearing chamber 7 for accommodating a lower bearing 8. A bushing 9 is fixedly connected in the lower bearing chamber 7, and the lower bearing 8 is fixedly connected in the bushing 9. The end of the rotor shaft 4 near the lower bearing seat 6 is connected to the lower bearing 8.

[0021] The motor 2 includes a housing 10, a stator 11, a rotor shaft 4, an upper bearing housing 13, and a lower bearing housing 6. The stator 11 and the rotor shaft 4 are both located inside the housing 10. The upper bearing housing 13 and the lower bearing housing 6 are located at both ends of the rotor shaft 4. The upper bearing housing 13 is fixedly connected to one end of the housing 10, and the lower bearing housing 6 is located inside the housing 10. An upper bearing 15 is provided between the rotor shaft 4 and the upper bearing housing 13, and a lower bearing 8 is provided between the rotor shaft 4 and the lower bearing housing 6.

[0022] By arranging the upper and lower bearing housings at both ends of the rotor shaft 4 respectively, and having the lower bearing housing 6 housed within the housing 10 and the upper bearing housing 13 connected to the end of the housing 10, a stable double-end support structure is formed. This ensures the coaxiality and rigidity of the rotor shaft 4 during high-speed rotation, and provides an independent installation space for the bushing 9 at the lower bearing 8. At the same time, the bearings at both ends share the radial load, so that the lower bearing 8 only needs to focus on bearing the axial force after insulation and isolation. The overall force distribution is more reasonable, the vibration of the motor 2 is significantly reduced, and the mechanical reliability after the anti-electro-corrosion modification is consolidated.

[0023] The housing 10 is provided with a pressure regulating diaphragm 16 at the end of the lower bearing seat 6 for adjusting the internal pressure of the motor 2.

[0024] A pressure regulating diaphragm 16 is installed at the lower end of the housing 10 to balance the pressure fluctuations inside the motor 2 caused by changes in water depth in real time, and to prevent excessive internal pressure from causing seal failure. At the same time, pressure regulation can reduce local stress concentration in the lower bearing chamber 7, protect the assembly clearance between the bushing 9 and the lower bearing 8 to maintain stability, and prevent axial movement caused by pressure difference from damaging the insulation layer. Thus, pressure protection measures are added on the basis of electrical isolation, improving the adaptability and lifespan of the whole machine in deep water or frequent start-stop conditions.

[0025] The pressure regulating diaphragm 16 is made of rubber and has an axial cross-section in the shape of an inverted triangle.

[0026] The rubber-material C-shaped cross-section structure combines elastic deformation and compressive resilience. When the internal pressure of motor 2 increases, the C-shaped sidewalls can expand outwards evenly, effectively absorbing pressure shocks; when the pressure decreases, it quickly returns to its original position, balancing the pressure difference inside and outside the motor cavity in real time, preventing negative pressure from drawing external moisture into motor 2. This shape design increases the effective deformation area, making the pressure regulation response more sensitive, while preventing the membrane from being excessively stretched and ruptured locally. This ensures that the environment around the lower bearing chamber 7 and bushing 9 is kept dry and clean for a long time, indirectly extending the electrical performance life of the insulation material.

[0027] The lower bearing housing 6 has a raised enclosure 17 forming a lower bearing chamber 7. The end of the enclosure 17 protrudes upward to form a limiting part 18. The lower bearing chamber 7 has a recessed annular positioning groove 19.

[0028] The enclosure 17 clearly delineates the boundary of the lower bearing chamber 7, the limiting part 18 provides an axial stop reference for the bushing 9, and the annular positioning groove 19 provides circumferential positioning for the bushing. This integrated molding structure simplifies the assembly process, allowing the bushing 9 to completely fit the entire inner wall of the lower bearing chamber 7 without the need for additional positioning parts, thus avoiding uneven insulation thickness or localized conductive contact caused by bushing misalignment. At the same time, the cooperation between the limiting part 18 and the annular positioning groove 19 ensures that the bushing will not shift or loosen when subjected to vibration, enhancing the long-term stability of insulation.

[0029] One end of the bushing 9 is provided with a positioning part 20, which is matched with the annular positioning groove 19. The other end of the bushing 9 is provided with a wrapping ring 21, and the wrapping ring 21 is provided with an annular protrusion 22. When the bushing 9 is fixed to the lower bearing chamber 7, the positioning part 20 is inserted into the annular positioning groove 19, the wrapping ring 21 wraps around the limiting part 18, and the annular protrusion 22 abuts against the limiting part 18, so that the bushing 9 covers the inner wall of the lower bearing chamber 7.

[0030] The bushing 9's full-enclosed coverage within the lower bearing housing 7 completely isolates the outer ring of the lower bearing 8 from the metal wall of the lower bearing seat 6, leaving no exposed contact surface. This completely cuts off the physical path of shaft current flowing through the bearing outer ring to the ground of the housing 10. Simultaneously, the enclosing ring 21 and the annular protrusion 22 form an elastic locking mechanism, which compensates for dimensional changes caused by thermal expansion and contraction, and generates radial preload to prevent bushing rotation. This ensures that the insulation layer does not wear or detach under long-term high-frequency vibration of the motor 2, greatly improving the durability and impact resistance of the insulation protection.

[0031] The bushing 9 is integrally molded from insulating material; the insulating material may be, for example, nylon 66 material with 30% glass fiber added.

[0032] 30% glass fiber reinforced nylon 66 combines high insulation resistance with excellent mechanical compressive strength and creep resistance. The polymer substrate itself can block conductive paths, and the glass fiber reinforced bushing can withstand the huge axial load transmitted by the bearing for a long time without deformation or cracking under pressure. The material is resistant to the high temperature of motor operation and wear resistance. The high-speed friction of the bearing will not quickly wear down the bushing insulation layer. The one-piece injection molding can accurately form the complex structure of the positioning part 20 and the wrapping ring 21, which is convenient to process and has high dimensional accuracy, taking into account both insulation protection and mechanical load-bearing requirements.

[0033] The connecting assembly 3 includes a connecting frame 23 and a connecting shaft 24. One end of the connecting shaft 24 is circumferentially fixed and axially movable relative to the rotor shaft 4. The other end of the connecting shaft 24 is drively connected to the water pump shaft 5. The rotor shaft 4 drives the water pump shaft 5 to rotate through the connecting shaft 24. One end of the connecting frame 23 is fixedly connected to the end of the motor 2, and the other end of the connecting frame 23 is fixedly connected to the pump body 1. The connecting frame 23 has a cavity inside, and the connecting shaft 24 is located in the cavity. The upper and lower ends of the connecting frame 23 are open. Water inlet holes 25 are distributed circumferentially on the outer side wall of the connecting frame 23. The water inlet holes 25 are connected to the cavity. The rotor shaft 4 is provided with a spline 26 at the end corresponding to the connecting frame 23. The connecting shaft 24 is provided with a keyway hole 27 at the end corresponding to the connecting frame 23. The end of the rotor shaft 4 is inserted into the keyway hole 27.

[0034] The spline 26 and keyway 27 work together to achieve a circumferentially fixed and axially floating connection between the rotor shaft 4 and the connecting shaft 24, which transmits large torque and allows for axial thermal expansion compensation, avoiding rigid impact on the lower bearing 8 due to axial movement. The cavity of the connecting frame 23 accommodates the connecting shaft 24, and the circumferential water inlet 25 allows the flowing liquid to continuously flush and cool the mating position of the connecting shaft 24, the water pump shaft 5, and the rotor shaft 4, reducing the heat generated by transmission friction. At the same time, the connecting frame 23 serves as a rigid transition piece between the motor 2 and the pump body 1, transferring the axial water thrust of the pump end to the housing 10 instead of the lower bearing 8, thus protecting the lower bearing 8 from external axial load interference.

[0035] The pump body 1 includes a pump casing 28, a flow guiding component 29, and an outlet end cover 12. The pump casing 28 adopts a hollow structure with openings at both ends. One end of the pump casing 28 is fixedly connected to the connecting component 3, and the other end of the pump casing 28 is connected to the outlet end cover 12. The outlet end cover 12 is provided with an outlet hole 14. The flow guiding component 29 is located inside the pump casing 28 to control the entry of external water into the pump casing 28 and guide it to the outlet end cover 12, and then deliver the water through the outlet hole 14.

[0036] The pump casing 28, open at both ends, forms a closed flow channel with the outlet end cover 12. The flow guiding component 29 guides the water flow orderly from the inlet hole 25 of the connecting frame 23, and after multi-stage pressurization, it is discharged from the outlet hole 14. The water flow path is smooth and the water pressure gradient is reasonable, avoiding turbulence and cavitation. The outlet end cover 12 concentrates drainage, reducing the backflow resistance inside the pump and improving the pump efficiency. At the same time, the pump casing 28 is rigidly connected to the connecting component 3, and the overall structure is compact. The water pressure reaction force is directly transmitted to the connecting frame 23 and the housing 10, without adding additional radial or axial load to the lower bearing 8, thus ensuring the mechanical pressure load of the bushing 9 and the lower bearing 8 while delivering water efficiently.

[0037] The flow guiding assembly 29 includes several guide vanes 30 and several impellers 31. The guide vanes 30 and impellers 31 are fixedly connected to the pump shaft 5. The impeller 31 is installed at one end of the pump casing 28 near the connecting frame 23, and the guide vane 30 is installed at one end of the pump casing 28 near the outlet end cover 12. The impellers 31 and guide vanes 30 are arranged alternately and evenly along the axial direction of the pump shaft 5. A retaining ring 32 is also provided between adjacent impellers 31 and guide vanes 30.

[0038] Impellers 31 and guide vanes 30 are arranged alternately and evenly to form a multi-stage pressurization unit. After each impeller 31 does work, the flow is rectified by the guide vanes 30 to eliminate swirl, thereby improving the suction efficiency of the next impeller 31 and significantly optimizing the overall head and flow characteristics. The baffle ring 32 separates adjacent impellers 31 and guide vanes 30, restricts the axial movement of each stage of the guide components, stabilizes the coaxiality of the pump shaft 5, and greatly reduces the axial vibration caused by water flow impact.

[0039] This invention adds a bushing 9 between the lower bearing 8 and the lower bearing housing 7. The bushing 9's insulating isolation function cuts off the conductive path from the rotor shaft 4, lower bearing 8, lower bearing housing 6, motor 2 housing 10 to the ground. This blocks the shaft current generated by the three-phase voltage difference and harmonic common-mode voltage during the operation of the permanent magnet motor 2 from being discharged to the ground through the lower bearing 8, eliminating bearing electro-corrosion. The lower bearing 8 only bears the axial mechanical load brought about by the operation of the equipment, restoring the bearing's mechanical working property of simply bearing rotation. This avoids the vicious cycle of increased frictional torque and increased operating current of the motor 2 caused by bearing corrosion, significantly extending the service life of the bearing and the entire motor 2, and reducing equipment maintenance and replacement costs.

[0040] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A submersible pump for preventing bearing electro-corrosion, comprising a pump body, a motor, and a connecting assembly, wherein the motor is provided with a rotor shaft, the pump body is provided with a water pump shaft, and the connecting assembly connects the rotor shaft and the water pump shaft, characterized in that: The motor has a lower bearing housing at its bottom, and a lower bearing chamber inside the lower bearing housing to accommodate the lower bearing. A bushing is fixedly connected inside the lower bearing chamber, and the lower bearing is fixedly connected inside the bushing. The end of the rotor shaft near the lower bearing housing is connected to the lower bearing.

2. A submersible pump for preventing bearing electro-corrosion according to claim 1, characterized in that: The motor includes a housing, a stator, a rotor shaft, an upper bearing housing, and a lower bearing housing. The stator and the rotor shaft are both located inside the housing. The upper bearing housing and the lower bearing housing are located at both ends of the rotor shaft. The upper bearing housing is fixedly connected to one end of the housing. The lower bearing housing is located inside the housing. An upper bearing is provided between the rotor shaft and the upper bearing housing, and a lower bearing is provided between the rotor shaft and the lower bearing housing.

3. A submersible pump for preventing bearing electro-corrosion according to claim 2, characterized in that: The housing has a pressure regulating diaphragm at the end located in the lower bearing seat for adjusting the internal pressure of the motor.

4. A submersible pump for preventing bearing electro-corrosion according to claim 3, characterized in that: The pressure regulating diaphragm is made of rubber and has an axial cross-section in the shape of an inverted triangle.

5. A submersible pump for preventing bearing electro-corrosion according to claim 1, characterized in that: The lower bearing housing has a raised enclosure forming a lower bearing chamber. The end of the enclosure protrudes upward to form a limiting part, and the lower bearing chamber has a recessed annular positioning groove.

6. A submersible pump for preventing bearing electro-corrosion according to claim 5, characterized in that: One end of the bushing is provided with a positioning part, which is matched with the annular positioning groove; the other end of the bushing is provided with a wrapping ring, and an annular protrusion is provided inside the wrapping ring. When the bushing is fixed to the lower bearing chamber, the positioning part is inserted into the annular positioning groove, the wrapping ring wraps around the limiting part, and the annular protrusion abuts against the limiting part, so that the bushing covers the inner wall of the lower bearing chamber.

7. A submersible pump for preventing bearing electro-corrosion according to claim 1, characterized in that: The bushing is integrally molded from insulating material.

8. A submersible pump for preventing bearing electro-corrosion according to claim 1, characterized in that: The connecting assembly includes a connecting frame and a connecting shaft. One end of the connecting shaft is circumferentially fixed and axially movable relative to the rotor shaft. The other end of the connecting shaft is drively connected to the water pump shaft. The rotor shaft drives the water pump shaft to rotate through the connecting shaft. One end of the connecting frame is fixedly connected to the motor end, and the other end of the connecting frame is fixedly connected to the pump body. The connecting frame has a cavity inside, and the connecting shaft is located in the cavity. The upper and lower ends of the connecting frame are open. Water inlet holes are distributed circumferentially on the outer side wall of the connecting frame, and the water inlet holes communicate with the cavity. The rotor shaft is provided with a spline at the end corresponding to the connecting frame, and a keyway hole is provided at the end corresponding to the connecting shaft. The end of the rotor shaft is inserted into the keyway hole.

9. A submersible pump for preventing bearing electro-corrosion according to claim 1, characterized in that: The pump body includes a pump casing, a flow guiding assembly, and a water outlet cover. The pump casing adopts a hollow structure with openings at both ends. One end of the pump casing is fixedly connected to the connecting assembly, and the other end of the pump casing is connected to the water outlet cover. The water outlet cover is provided with a water outlet hole. The flow guiding assembly is located inside the pump casing to control the entry of external water into the pump casing and guide it to the water outlet cover, and then deliver the water out through the water outlet hole.

10. A submersible pump for preventing bearing electro-corrosion according to claim 9, characterized in that: The flow guiding assembly includes several guide vanes and several impellers. The guide vanes and impellers are fixedly connected to the pump shaft. An impeller is mounted on one end of the pump casing near the connecting frame, and the guide vane is mounted on the other end of the pump casing near the outlet end cover. The impellers and guide vanes are arranged alternately and evenly along the pump shaft axis, and a retaining ring is provided between adjacent impellers and guide vanes.

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