Rotor structure of submersible permanent magnet synchronous motor

Abstract

The invention relates to the technical field of submersible motors, and provides a rotor structure of a submersible permanent magnet synchronous motor, which comprises a main body, a power mechanism and a connecting mechanism, and is characterized in that the top of the main body is in threaded connection with a cover plate. The rotor structure of the submersible permanent magnet synchronous motor is provided with a samarium-cobalt permanent magnet, and the samarium-cobalt permanent magnet has excellent temperature stability, corrosion resistance and stable and reliable magnetic performance; the titanium alloy transmission shaft can adapt to the high-temperature, high-pressure and strong-corrosion environments through the arrangement of the titanium alloy transmission shaft, the excellent performance is achieved in the oil exploitation work, the size of the transmission shaft is remarkably reduced while the strength is guaranteed, the outer diameter of the rotor can be reduced, and the service life of the rotor is prolonged. The device is suitable for underground narrow space; by arranging the spline sleeve and the spline sleeve rod, the adjacent motor rotors can be connected through the spline sleeve rod and the spline sleeve, shaft thermal expansion and cold contraction caused by underground temperature changes are adapted, meanwhile, the spline meshing area is large, and connection is more reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of submersible motors, in particular to a rotor structure of a submersible permanent magnet synchronous motor. Background Art

[0002] As a core component of artificial lift systems in oil production, submersible permanent magnet synchronous motors (PMSMs) efficiently convert electrical energy directly into mechanical energy, driving pumpjacks to lift fluids to the surface. They are widely used in deep and ultra-deep well operations. Compared to traditional asynchronous motors, PMSMs offer higher power factor, improved efficiency, and a smaller footprint, making them particularly suitable for confined spaces and long deployments underground. By utilizing rare earth permanent magnet materials, they maintain stable output at high torque and low speed, minimizing energy loss and lowering the power demand on surface drive equipment, significantly improving oilfield recovery and reducing energy consumption. Their high power density and compact structure reduce the number of motors in series, simplifying system installation, and reducing non-productive time and operating costs, providing key technical support for the development of mature and unconventional oil and gas resources. Recent advances in multiphysics simulation technology and nanoscale permanent magnet materials have significantly optimized thermal management and electromagnetic design, laying the theoretical and engineering foundation for reliable operation in deeper wells and higher temperature environments.

[0003] However, in the high-temperature environment underground, there is a risk of irreversible demagnetization of rare earth magnets, resulting in a decrease in motor power and unstable operation. Because the underground medium is mostly hydrogen sulfide and high-salinity fluid, traditional steel drive shafts are prone to corrosion and rust, which not only increases bearing wear but may also shorten the overall life due to rust particles interfering with dynamic balance. The limited space underground places strict restrictions on the outer diameter of the motor, making heat dissipation more difficult. If the heat cannot be released in time, it will lead to accelerated aging of the insulation material and an increased risk of thermal failure of the system. In addition, during the assembly of the multi-segment rotor, due to positioning errors between components, rotor alignment is difficult, which may cause mechanical vibration and additional wear, affecting the long-term stable operation of the motor. Summary of the Invention

[0004] The purpose of the present invention is to provide a submersible permanent magnet synchronous motor rotor structure to solve the risk of irreversible demagnetization of rare earth magnets in the high-temperature environment underground, which is raised in the above-mentioned background technology, leading to a decrease in motor power and unstable operation. Since the underground medium is mostly hydrogen sulfide-containing and high-salinity fluids, traditional steel drive shafts are prone to corrosion and rust, which not only increases bearing wear, but also may shorten the overall life due to rust particles interfering with dynamic balance. The limited space underground imposes strict restrictions on the outer diameter of the motor, making heat dissipation more difficult. If the heat cannot be released in time, it will lead to accelerated aging of the insulation material and an increased risk of thermal failure of the system. In addition, during the assembly of the multi-segment rotor, due to the positioning error between the components, the rotor alignment is difficult, which may cause mechanical vibration and additional wear, affecting the long-term stable operation of the motor.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a submersible permanent magnet synchronous motor rotor structure, comprising a main body, a cover plate, a power mechanism and a connecting mechanism, the top of the main body being threadedly connected to the cover plate, the inside of the main body being installed with a power mechanism, and connecting mechanisms being provided at both ends of the power mechanism, and the connecting mechanisms protrude from the main body and the cover plate.

[0006] Preferably, the main body is a hollow cylindrical structure, a thread is provided on one side of the interior of the main body, an opening is provided at the bottom of the main body, the inner side of one end of the main body is fixedly connected to the cover plate by a thread, an opening is provided at the axis center of the cover plate, and the top end of the cover plate is fixedly connected to a regular hexagonal fastening nut.

[0007] Preferably, the power mechanism includes a partition plate, a permanent magnet and a transmission shaft. The partition plate is welded inside the main body, and the permanent magnet is clamped in the wider compartment of the partition plate.

[0008] Preferably, the permanent magnet is arc-shaped, the long arc end of the permanent magnet is close to the inner side of the main body, the permanent magnets are arranged in four groups and are evenly arranged, the height of the permanent magnets is consistent with the distance from the inner bottom of the main body to the bottom end of the cover plate, and the permanent magnets are made of samarium cobalt.

[0009] Preferably, eight groups of partition plates are provided, and each two groups of partition plates are clamped with a group of permanent magnets, and the heights of the partition plates match those of the permanent magnets.

[0010] Preferably, a projection of the transmission shaft is clamped in the narrow compartment of the partition plate, and two sides of the projection of the transmission shaft are tightly fitted with the surface of the partition plate.

[0011] Preferably, the transmission shaft height matches the permanent magnet, and the transmission shaft is made of titanium alloy.

[0012] Preferably, the connecting mechanism includes a spline sleeve and a spline sleeve rod, the spline sleeve is fixedly connected to the top end of the transmission shaft, the spline sleeve rod is welded to the bottom end of the transmission shaft, and the outer surface of the spline sleeve rod matches the inner surface shape of the spline sleeve.

[0013] Preferably, the spline sleeve passes through the opening of the cover plate and protrudes from the cover plate, and the spline sleeve rod passes through the opening at the bottom of the main body and protrudes from the main body.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a samarium-cobalt permanent magnet, which has excellent temperature stability and corrosion resistance, and stable and reliable magnetic properties, making it particularly suitable for use in oil wells with high temperatures and harsh environments. Furthermore, the present invention provides a titanium alloy drive shaft, which can adapt to high temperatures, high pressures, and highly corrosive environments, and has excellent performance in oil production. While ensuring strength, the volume of the drive shaft is significantly reduced, allowing the outer diameter of the rotor to be reduced, adapting to the narrow space underground. The present invention provides a spline sleeve and a spline rod. The spline sleeve and the spline rod can connect the rotors of adjacent motors to adapt to the thermal expansion and contraction of the shaft caused by temperature changes in the well. At the same time, the spline engagement area is large, making the connection more reliable. The spline sleeve and the spline rod with inwardly reduced bottom ends no longer need to be manually aligned when connecting the rotors of different motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the appearance structure of the present invention.

[0016] Figure 2 It is a schematic diagram of the coordination of the main body, partition plate and permanent magnet of the present invention.

[0017] Figure 3 It is a schematic diagram of the coordination of the main body, partition plate and transmission shaft of the present invention.

[0018] Figure 4 It is a schematic cross-sectional view of the transmission shaft of the present invention.

[0019] In the figure: 1. Main body; 2. Cover plate; 3. Power mechanism; 301. Partition plate; 302. Permanent magnet; 303. Transmission shaft; 4. Connecting mechanism; 401. Spline sleeve; 402. Spline sleeve rod. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0021] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection or an electrical connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] See also Figure 1-4 An embodiment of the present invention provides: a submersible permanent magnet synchronous motor rotor structure, including a main body 1, a cover plate 2, a power mechanism 3 and a connecting mechanism 4, characterized in that: the top of the main body 1 is threadedly connected to the cover plate 2, the power mechanism 3 is installed inside the main body 1, and connecting mechanisms 4 are provided at both ends of the power mechanism 3, and the connecting mechanism 4 protrudes from the main body 1 and the cover plate 2.

[0025] Specifically, the main body 1 is a hollow cylindrical structure, a thread is provided on one side of the inside of the main body 1, an opening is provided at the bottom of the main body 1, the inner thread of one end of the main body 1 is fixedly connected to the cover plate 2, an opening is provided at the axis center of the cover plate 2, and the top end of the cover plate 2 is fixedly connected to a regular hexagonal fastening nut.

[0026] Specifically, the power mechanism 3 includes a partition plate 301, a permanent magnet 302 and a transmission shaft 303. The partition plate 301 is welded inside the main body 1, and the permanent magnet 302 is clamped in the wider compartment of the partition plate 301. The partition plate 301 is used to fix the position of the permanent magnet 302 and the transmission shaft 303, which can make the overall rotor more stable and facilitate the disassembly and replacement of parts.

[0027] Specifically, the permanent magnet 302 is arc-shaped, and the long arc end of the permanent magnet 302 is close to the inner side of the main body 1. The permanent magnet 302 is set in four groups and is evenly arranged. The height of the permanent magnet 302 is consistent with the distance from the inner bottom of the main body 1 to the bottom end of the cover plate 2. The permanent magnet 302 is made of samarium cobalt. The permanent magnet 302 made of samarium cobalt has excellent temperature stability and corrosion resistance, and the magnetic properties are stable and reliable. It is especially suitable for use in high-temperature and harsh environment oil wells, and can enhance the stability of the device during use.

[0028] Specifically, eight groups of partition plates 301 are provided, and each two groups of partition plates 301 are clamped with one group of permanent magnets 302 . The height of the partition plates 301 matches that of the permanent magnets 302 .

[0029] Specifically, the protrusion of the transmission shaft 303 is clamped in the narrow compartment of the partition plate 301 , and both sides of the protrusion of the transmission shaft 303 are tightly fitted with the surface of the partition plate 301 .

[0030] Specifically, the height of the drive shaft 303 matches the permanent magnet 302. The drive shaft 303 is made of titanium alloy. The titanium alloy drive shaft 303 can adapt to high temperature, high pressure and highly corrosive environments, and has excellent performance in oil production. While ensuring strength, the volume of the drive shaft 303 is significantly reduced, so that the outer diameter of the rotor can be reduced to adapt to the narrow space underground.

[0031] Specifically, the connecting mechanism 4 includes a spline sleeve 401 and a spline sleeve rod 402. The spline sleeve 401 is fixedly connected to the top end of the transmission shaft 303. The spline sleeve rod 402 is welded to the bottom end of the transmission shaft 303. The outer surface of the spline sleeve rod 402 matches the inner surface shape of the spline sleeve 401. The spline sleeve rod 402 and the spline sleeve 401 can connect adjacent motor rotors to adapt to the thermal expansion and contraction of the shaft caused by temperature changes underground. At the same time, the spline meshing area is large, making the connection more reliable.

[0032] Specifically, the spline sleeve 401 passes through the opening of the cover plate 2 and protrudes from the cover plate 2. The spline sleeve rod 402 passes through the opening at the bottom of the main body 1 and protrudes from the main body 1 for easy docking.

[0033] Working principle: First, the spline sleeve 402 and the spline sleeve 401 can connect the rotors of adjacent motors to adapt to the thermal expansion and contraction of the shaft caused by temperature changes underground. At the same time, the spline engagement area is large, making the connection more reliable. The spline sleeve 401 and the spline sleeve 402 with their bottom ends narrowing inward no longer need to manually align the drive shaft 303 when connecting the rotors of different motors. When in use, the permanent magnet 302 made of samarium cobalt has excellent temperature stability and corrosion resistance, and its magnetic properties are stable and reliable. It is especially suitable for use in high-temperature and harsh environments in oil wells. At the same time, the titanium alloy drive shaft 303 can adapt to high temperature, high pressure and highly corrosive environments, and has outstanding performance in oil production work. While ensuring strength, the volume of the drive shaft 303 is significantly reduced, so that the outer diameter of the rotor can be reduced to adapt to the narrow space underground.

[0034] The above is only an embodiment of the present invention, and common sense such as the specific structure and characteristics of the scheme are not described in detail here. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claim involved.

Claims

1. A submersible permanent magnet synchronous motor rotor structure, comprising a main body (1), a cover plate (2), a power mechanism (3) and a connecting mechanism (4), characterized in that: The top of the main body (1) is threadedly connected to a cover plate (2), a power mechanism (3) is installed inside the main body (1), and connecting mechanisms (4) are provided at both ends of the power mechanism (3), and the connecting mechanisms (4) protrude from the main body (1) and the cover plate (2).

2. The rotor structure of a submersible permanent magnet synchronous motor according to claim 1, characterized in that: The main body (1) is a hollow cylindrical structure. A thread is provided on one side of the interior of the main body (1). An opening is provided at the bottom of the main body (1). The inner side of one end of the main body (1) is fixedly connected to the cover plate (2) by a thread. An opening is provided at the axis of the cover plate (2). The top end of the cover plate (2) is fixedly connected to a regular hexagonal fastening nut.

3. The rotor structure of a submersible permanent magnet synchronous motor according to claim 1, characterized in that: The power mechanism (3) comprises a partition plate (301), a permanent magnet (302) and a transmission shaft (303); the partition plate (301) is welded inside the main body (1); and the permanent magnet (302) is clamped in a wider compartment of the partition plate (301).

4. The rotor structure of a submersible permanent magnet synchronous motor according to claim 3, characterized in that: The permanent magnet (302) is arc-shaped, and the long arc end of the permanent magnet (302) is in close contact with the inner side of the main body (1). The permanent magnet (302) is provided in four groups and is evenly arranged. The height of the permanent magnet (302) is consistent with the distance from the inner bottom of the main body (1) to the bottom end of the cover plate (2). The permanent magnet (302) is made of samarium cobalt.

5. The submersible permanent magnet synchronous motor rotor structure according to claim 3, characterized in that: A total of eight groups of partition plates (301) are provided, and every two groups of partition plates (301) are clamped to one group of permanent magnets (302), and the heights of the partition plates (301) and the permanent magnets (302) match each other.

6. The rotor structure of a submersible permanent magnet synchronous motor according to claim 3, characterized in that: The projection of the transmission shaft (303) is clamped in the narrow compartment of the partition plate (301), and both sides of the projection of the transmission shaft (303) are tightly fitted to the surface of the partition plate (301).

7. The rotor structure of a submersible permanent magnet synchronous motor according to claim 6, characterized in that: The transmission shaft (303) is height-matched with the permanent magnet (302), and the transmission shaft (303) is made of titanium alloy.

8. The submersible permanent magnet synchronous motor rotor structure according to claim 1, characterized in that: The connecting mechanism (4) comprises a spline sleeve (401) and a spline sleeve rod (402), wherein the spline sleeve (401) is fixedly connected to the top end of the transmission shaft (303), and the spline sleeve rod (402) is welded to the bottom end of the transmission shaft (303), and the outer surface of the spline sleeve rod (402) matches the inner surface of the spline sleeve (401).

9. The rotor structure of a submersible permanent magnet synchronous motor according to claim 8, characterized in that: The spline sleeve (401) passes through the opening of the cover plate (2) and protrudes from the cover plate (2); the spline sleeve rod (402) passes through the opening at the bottom of the main body (1) and protrudes from the main body (1).

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