Deep sea submersible pump motor structure

Abstract

This invention discloses a deep-sea submersible pump motor structure, comprising: a housing, which is a vertical housing structure open at both ends for withstanding external pressure in the deep sea; a stator disposed on the circumferential side of the inner wall of the housing; an upper bearing housing and a lower bearing housing, respectively fastened to the housing located on the upper and lower sides of the stator; an upper radial bearing and a lower radial bearing, respectively press-fitted onto the upper bearing housing and the lower bearing housing; a main shaft, axially rotatable and supported within the housing via the upper and lower radial bearings; and a rotor, interference-fitted onto the main shaft, with the rotor located between the inner walls of the stator; the radial X-direction and Y-direction oil film stiffness of the upper and lower radial bearings are 1.11 × 10⁻⁶ and 1.11 × 10⁻⁶, respectively, under the rated speed of 4991 rpm. 5 -1.24×10 5 N / mm and 1.32×10 5 -1.37×10 5 The oil film damping in the radial X and radial Y directions is 1.97×10²-2.35×10²Ns / mm and 1.88×10²-2.29×10²Ns / mm, respectively. This invention can ensure the long-term stable operation of the motor, meeting the high requirements for motor reliability, lifespan, and stability in the global oil and gas resource development extending to the deep sea.

Description

Technical Field

[0001] This invention belongs to the field of deep-sea submersible pump motor technology, and more specifically, it relates to an 800kW deep-sea submersible pump motor structure suitable for environments at depths of 1500 meters and above. Background Technology

[0002] Deep-sea submersible pump motors are the core drive equipment of deep-sea oil and gas extraction systems, mainly used to drive submersible pumps to transport crude oil from the seabed at depths of 1500 meters or even deeper to surface platforms. These motors need to operate in extremely harsh marine environments for extended periods, with typical operating conditions including: approximately 15 MPa hydrostatic pressure at a depth of 1500 meters, a low temperature environment of 3-4°C, and the strong corrosive effects of high-salinity seawater.

[0003] As global oil and gas resource development extends to deeper waters, higher demands are placed on the reliability, lifespan, and stability of deep-sea submersible pump motors. However, existing technologies in this field face the following key technical bottlenecks:

[0004] 1. The lack of theoretical guidance in the design of spindle and bearing matching makes vibration control difficult. In existing technologies, the design of spindle diameter and the selection of bearing stiffness are often based on experience or a single indicator, lacking a clear definition of the optimal matching range between the two. This leads to excessive spindle vibration at rated speed, causing uneven air gap between stator and rotor, increasing vibration noise, and shortening motor life.

[0005] 2. Insufficient basis for setting oil filling pressure limits structural safety. Deep-sea submersible oil pump motors generally adopt an oil-filled structure, which balances the external seawater pressure by filling the inside with insulating oil, protecting the internal windings and insulation system. Existing technologies mostly adopt the design principle of "equal internal and external pressure" (15MPa external pressure corresponds to 15MPa internal pressure). However, this is not the most reasonable oil filling pressure, which leads to the maximum deformation of the casing exceeding the limit and excessive structural stress.

[0006] 3. Improper control of the preload force of the top cover bolts results in poor sealing reliability. The bolted connection between the top cover and the housing is a key part of the pressure sealing of the deep-sea motor. The bolt preload directly determines the contact pressure and connection strength of the sealing surface. Insufficient preload can easily lead to seawater leakage, while excessive preload can cause the bolt to yield and break, making it difficult to balance sealing and strength. Summary of the Invention

[0007] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a deep-sea submersible pump motor structure, aiming to solve problems such as insufficient pressure-bearing capacity, seal failure, or component strength risks caused by improper matching of the main shaft and bearings, unreasonable oil filling pressure settings, and poor control of the preload of the top cover bolts in existing deep-sea motors.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a deep-sea submersible oil pump motor structure, comprising: a housing, which is a vertical housing structure with open ends for bearing the external pressure of the deep sea; a stator, disposed on the circumferential side of the inner wall of the housing; an upper bearing seat and a lower bearing seat, respectively fastened to the housing located on the upper and lower sides of the stator; an upper radial bearing and a lower radial bearing, respectively press-fitted onto the upper bearing seat and the lower bearing seat; a main shaft, axially rotatable and supported within the housing via the upper and lower radial bearings; a rotor, interference-fitted onto the main shaft, and the rotor being located between the inner walls of the stator; and a top cover, sealed and fastened to the upper end of the housing by multiple top cover bolts; wherein, the outer diameter of the main shaft is 197 mm and the length is 1.817 m, and the oil film stiffness of the upper and lower radial bearings at a rated speed of 4991 rpm satisfies the following: radial X-direction oil film stiffness is 1.11 × 10⁻⁶. 5 -1.24×10 5 N / mm, radial Y-axis oil film stiffness is 1.32×10 5 -1.37×10 5 The radial X-direction oil film damping is 1.97×10²-2.35×10²N / mm. The radial Y-axis oil film damping is 1.88×10²-2.29×10²N (s / mm). s / mm.

[0009] Preferably, the stator, rotor, upper bearing housing, and lower bearing housing are first assembled as a whole using a sleeve, and then the sleeve is interference-fitted into the housing.

[0010] Preferably, an upper guide thrust bearing is installed at the upper end of the main shaft to bear the axial gravity of the rotor, and the rated dynamic load of the upper guide thrust bearing is not less than 550kN, with an axial clearance of 0.05mm reserved during installation.

[0011] Preferably, the motor has an internal oil-filled sealed structure, including an insulating oil chamber and a pressure control module. In a deep-sea environment of 1500 meters, the pressure control module stabilizes the oil filling pressure in the insulating oil chamber at 7.1 MPa.

[0012] Preferably, the insulating oil used in the oil-filled sealing structure is a low-temperature resistant mineral insulating oil with a viscosity ≤100MPa at 3-4℃. s. Breakdown voltage ≥ 50kV; The pressure control module has a pressure feedback function and can automatically adjust when the oil filling pressure deviation exceeds ±0.2MPa.

[0013] Preferably, the top cover bolts are 12.9 grade M33 fully threaded bolts with 24 through holes, and the preload of the top cover bolts is set to 3 × 10⁻⁶. 5 N.

[0014] Preferably, the housing is made of duplex steel 2507, with an outer diameter of 800mm and a length of 2.14m.

[0015] Preferably, the stator inner diameter is 375mm, the rotor inner diameter is 197mm, the stator-rotor air gap is 8mm, and the stator winding is a double-layer lapped Y-type connection.

[0016] The present invention has the following advantages due to the adoption of the above technical solutions: 1. Through precise matching design of bearing stiffness and damping characteristics, the spindle vibration amplitude is effectively controlled to ≤0.3mm, avoiding the problem of uneven air gap between stator and rotor caused by excessive vibration, reducing vibration noise, and extending the service life of the motor. The precise setting of the oil film stiffness and damping parameters of the upper and lower guide radial bearings breaks through the bottleneck of lack of theoretical guidance in the existing technology for spindle and bearing matching design, and achieves optimal adaptation of the spindle and bearing system.

[0017] 2. The internal oil filling pressure is innovatively set to 7.1MPa, instead of the traditional 15MPa equal to the external seawater pressure. In a deep-sea environment of 1500 meters, the stress of both the stator and the top cover is 203MPa, achieving the optimal stress distribution of the overall structure, meeting the requirements of equal strength design, and improving the overall pressure bearing capacity and operational reliability.

[0018] 3. Use 24 M33 grade 12.9 fully threaded bolts, and precisely set the preload of the top cover bolts to 3.0 × 10⁻⁶. 5 N ensures both a good seal and minimizes bolt stress while maximizing bolt strength, effectively solving the problem of balancing sealing and strength, and significantly improving sealing reliability and structural safety. This design also addresses the problem of poor sealing reliability caused by improper control of the preload force of the top cover bolts in existing technologies.

[0019] 4. Through the coordinated optimization of the bearing system, oil filling pressure system and top cover bolt connection system, a complete technical system has been formed, which can effectively adapt to the service requirements of deep-sea submersible oil pump motors at depths of 1,500 meters and above, providing technical support for the localization process of deep-sea submersible oil pump motors.

[0020] This invention is particularly suitable for extreme working conditions such as high pressure, low temperature, and high corrosion in the deep sea, ensuring long-term stable operation of the motor and meeting the high requirements for motor reliability, lifespan, and stability in the extension of global oil and gas resource development to the deep sea. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings: Figure 1 This is an external view of a deep-sea submersible oil pump motor structure provided in an embodiment of the present invention; Figure 2 This is a cross-sectional view of a deep-sea submersible oil pump motor structure provided in an embodiment of the present invention; Figure 3 The curves showing the effect of oil filling pressure on stress demonstrate the stress changes of the stator and top cover under different oil filling pressures in a deep-sea environment of 1500 meters. Figure 4 The graph shows the relationship between the preload force and stress of the top cover bolts, illustrating the changes in bolt stress and sealing performance under different preload forces.

[0022] The markings in the diagram are as follows: 1-Stator; 2-Rotor core; 3-Main shaft; 4-Top cover bolt; 5-Top cover; 6-Upper guide thrust bearing; 7-Upper bearing housing; 8-Upper guide radial bearing; 9-Sleeve; 10-Outer shell; 11-Lower guide radial bearing; 12-Lower bearing housing; 13-Insulating oil cavity. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this invention and simplifying the description, and are not intended to 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 this invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] The deep-sea submersible pump motor structure provided by this invention includes: a housing, which is a vertical housing structure with open ends for withstanding external deep-sea pressure; a stator, disposed on the inner wall of the housing; an upper bearing seat and a lower bearing seat, respectively fastened to the housing located on the upper and lower sides of the stator; an upper radial bearing and a lower radial bearing, respectively press-fitted onto the upper and lower bearing seats; a main shaft, axially rotatable and supported within the housing by the upper and lower radial bearings; and a rotor, interference-fitted onto the main shaft, with the rotor located between the inner walls of the stator; the main shaft has an outer diameter of 197 mm and a length of 1.817 m, and the upper and lower radial bearings have an oil film stiffness of 1.11 × 10⁻⁶ in the radial X and Y directions at a rated speed of 4991 rpm. 5 -1.24×10 5 N / mm and 1.32×10 5 -1.37×10 5 N / mm, oil film damping is 1.97×10²-2.35×10²N The oil film damping is 1.88×10²-2.29×10²N (s / mm). s / mm. This invention can ensure the long-term stable operation of the motor, meeting the high requirements for motor reliability, lifespan, and stability brought about by the extension of global oil and gas resource development to the deep sea.

[0030] The structure of the deep-sea submersible pump motor provided in the embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] Please see Figure 1 , Figure 2 The deep-sea submersible pump motor structure provided by the present invention includes: a housing 10, which is a vertical housing structure with open ends, used to withstand the external pressure of the deep sea; a stator 1, which is disposed on the inner wall of the housing 10; an upper bearing seat 7 and a lower bearing seat 12, which are respectively fastened to the housing 10 located on the upper and lower sides of the stator 1; an upper radial bearing 8 and a lower radial bearing 11, which are respectively press-fitted onto the upper bearing seat 7 and the lower bearing seat 12; a main shaft 3, which is axially rotatably supported in the housing 10 by the upper radial bearing 8 and the lower radial bearing 11; a rotor 2, which is interference-fitted onto the main shaft 3 and located between the inner walls of the stator 1; and a top cover 5, which is sealed and fastened to the upper end of the housing 10 by a plurality of top cover bolts 4.

[0032] The main shaft 3 has an outer diameter of 197mm and a length of 1.817m. Meanwhile, the upper radial bearing 8 and the lower radial bearing 11, under a rated speed of 4991rpm, meet the following oil film stiffness requirements: radial X-direction (Kxx) oil film stiffness is 1.11×10⁻⁶. 5 -1.24×10 5 N / mm, radial Y-axis (Kyy) oil film stiffness is 1.32×10 5-1.37×10 5 The radial (Cxx) oil film damping is 1.97×10²-2.35×10²N / mm. The radial (Y) direction (Cyy) oil film damping is 1.88 × 10² - 2.29 × 10² N (s / mm). The precise bearing parameter design effectively controls the vibration amplitude of the main shaft 3 to ≤0.3mm, thereby avoiding uneven air gap between the stator and rotor caused by excessive vibration, reducing vibration noise, and extending the service life of the motor.

[0033] In the above embodiments, preferably, the stator 1, rotor 2, upper bearing housing 7 and lower bearing housing 12 are first installed as a whole by means of sleeve 9, and then the sleeve 9 is interference-fitted into the inside of the housing 10. This not only greatly improves the ease of installation, but also greatly reduces the parts that need to be precision machined.

[0034] In the above embodiments, preferably, an upper guide thrust bearing 6 is installed on the upper end of the main shaft 3 to bear the axial gravity of the rotor 2 (not less than 6kN), and the rated dynamic load of the upper guide thrust bearing is not less than 550kN, with a 0.05mm axial clearance reserved during installation.

[0035] In the above embodiments, preferably, the motor interior adopts an oil-filled sealed structure, including an insulating oil chamber 13 and a pressure control module (not shown in the figure). In a deep-sea environment of 1500 meters (external seawater pressure 15 MPa), the pressure control module stabilizes the oil filling pressure in the insulating oil chamber 13 at 7.1 MPa. At this point, the stator and top cover stresses are both 203 MPa (see [reference]). Figure 3 This allows for the optimal overall stress distribution of the structure, meeting the requirements for equal strength design.

[0036] In the above embodiments, preferably, the insulating oil of the oil-filled sealing structure is a low-temperature resistant mineral insulating oil with a viscosity ≤100MPa at 3-4℃ (1500-meter deep sea temperature). The breakdown voltage is ≥50kV, ensuring insulation performance and fluidity in the low-temperature environment of the deep sea; the pressure control module has a pressure feedback function, and can automatically adjust when the oil filling pressure deviation exceeds ±0.2MPa.

[0037] In the above embodiments, preferably, the top cover bolt 4 is a 12.9 grade M33 fully threaded bolt with a 24-hole structure, and the preload of the top cover bolt 4 is set to 3×10. 5 N, as proven by testing, not only ensures a good seal but also minimizes bolt stress and maximizes bolt strength (see [link]). Figure 4 ).

[0038] In the above embodiments, preferably, the housing 10 is made of duplex steel 2507, with an outer diameter of 800mm and a length of 2.14m. The selection of this high-strength and corrosion-resistant material ensures the structural strength and durability of the motor in the high-pressure and highly corrosive environment of the deep sea.

[0039] In the above embodiments, preferably, the inner diameter of stator 1 is 375mm, the inner diameter of rotor 2 is 197mm, the air gap between stator and rotor is 8mm, and the stator winding is a double-layer lapped Y-type connection. This design fully considers the electromagnetic performance requirements in the deep-sea environment and ensures the efficient and stable operation of the motor in the deep-sea environment.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. 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. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A deep-sea submersible oil pump motor structure, characterized in that, include: The casing is a vertical shell structure with openings at both ends, designed to withstand the external pressure of the deep sea; The stator is disposed on the periphery of the inner wall of the housing; The upper bearing housing and the lower bearing housing are respectively fastened to the housing located on the upper and lower sides of the stator; The upper guide radial bearing and the lower guide radial bearing are respectively press-fitted onto the upper bearing housing and the lower bearing housing; The main shaft is axially supported within the housing via the upper and lower radial guide bearings. The rotor is interference-fitted onto the main shaft, and the rotor is located between the inner walls of the stator; The top cover is securely connected to the upper end of the housing by multiple top cover bolts; The main shaft has an outer diameter of 197 mm and a length of 1.817 m. Furthermore, the upper and lower radial bearings, under a rated speed of 4991 rpm, meet the following oil film stiffness requirements: radial X-direction oil film stiffness is 1.11 × 10⁻⁶. 5 -1.24×10 5 N / mm, radial Y-axis oil film stiffness is 1.32×10 5 -1.37×10 5 The radial X-direction oil film damping is 1.97×10²-2.35×10²N / mm. The radial Y-axis oil film damping is 1.88×10²-2.29×10²N (s / mm). s / mm.

2. The deep-sea submersible pump motor structure according to claim 1, characterized in that, The stator, rotor, upper bearing housing, and lower bearing housing are first assembled as a whole using a sleeve, and then the sleeve is interference-fitted into the housing.

3. The deep-sea submersible pump motor structure according to claim 1, characterized in that, An upper guide thrust bearing is installed at the upper end of the main shaft to bear the axial gravity of the rotor, and the rated dynamic load of the upper guide thrust bearing is not less than 550kN, with an axial clearance of 0.05mm reserved during installation.

4. The deep-sea submersible pump motor structure according to claim 1, characterized in that, The motor has an internal oil-filled sealed structure, including an insulating oil chamber and a pressure control module. In a deep-sea environment of 1500 meters, the pressure control module stabilizes the oil filling pressure in the insulating oil chamber at 7.1 MPa.

5. The deep-sea submersible oil pump motor structure according to claim 4, characterized in that, The insulating oil used in the oil-filled sealing structure is a low-temperature resistant mineral insulating oil with a viscosity ≤100MPa at 3-4℃. s. Breakdown voltage ≥ 50kV; The pressure control module has a pressure feedback function and can automatically adjust when the oil filling pressure deviation exceeds ±0.2MPa.

6. The deep-sea submersible pump motor structure according to claim 1, characterized in that, The top cover bolts are 12.9 grade M33 fully threaded bolts with 24 through holes, and the preload force of the top cover bolts is set to 3 × 10. 5 N.

7. The deep-sea submersible pump motor structure according to claim 1, characterized in that, The casing is made of duplex steel 2507, with an outer diameter of 800mm and a length of 2.14m.

8. The deep-sea submersible pump motor structure according to claim 1, characterized in that, The stator inner diameter is 375mm, the rotor inner diameter is 197mm, the stator-rotor air gap is 8mm, and the stator winding is a double-layer lapped Y-type connection.

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