Permanent magnet motor water-cooled submersible pump

Abstract

The utility model relates to submersible pump technical field, the utility model provides a permanent magnet motor water -cooling type submersible pump, it includes mounting bush, and mounting bush has installation cavity, stator sets up in installation cavity, and stator has magnetic cavity, and rotor is set up in magnetic cavity and penetrates, and rotor includes: locating piece, locating piece is set up and is arranged in several extension, and locating piece has magnetic steel groove and water through -hole, and edge has the magnetic separation groove, and permanent magnet sets up in magnetic steel groove, and the cooling liquid is set up in installation cavity, and the cooling liquid fills water through -hole, is used for cooling rotor, and the input of pump body and the output of rotor are connected. Solve the technical problem of poor heat dissipation effect of permanent magnet motor rotor in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of submersible pump technology, specifically to a water-cooled submersible pump with a permanent magnet motor. Background Technology

[0002] In the field of submersible pumps, permanent magnet motors are widely used in deep well water extraction, industrial circulating water, and other scenarios due to their advantages such as high efficiency, energy saving, and small size. However, traditional permanent magnet motor submersible pumps suffer from problems such as low rotor cooling efficiency, difficult structural maintenance, and poor high-temperature adaptability, which seriously restrict their long-term stable operation and adaptability to various working conditions. As submersible pumps extend to complex scenarios such as deep wells and high-temperature fluids, the shortcomings of traditional structures in terms of heat dissipation, reliability, and operation and maintenance costs become increasingly prominent, becoming a key bottleneck restricting the performance upgrade of permanent magnet motor submersible pumps.

[0003] Early permanent magnet submersible pump rotors mostly adopted a "cast encapsulation" structure (such as aluminum casting or resin casting), where the positioning plate and permanent magnet were solidified into a single unit through casting. This design has significant thermal resistance defects: the contact thermal resistance between the casting and the positioning plate is as high as 10-15 m²·K / W. Even though cast aluminum itself has a high thermal conductivity (237 W / (m·K)), the heat generated by the rotor (such as eddy current losses in the permanent magnet and iron losses in the silicon steel sheet) is difficult to transfer quickly to the coolant, causing the permanent magnet operating temperature to often reach 100-120℃, approaching its demagnetization temperature (≥150℃). In the high-temperature environment of deep wells (downhole temperature > 60℃), the risk of high-temperature demagnetization increases significantly, motor efficiency can decrease by more than 20%, and even cause permanent failure of the permanent magnet, with an equipment scrap rate as high as 15%.

[0004] Traditional casting encapsulation also leads to problems such as cooling channel blockage and flow resistance. During the casting filling process, air bubbles and overflow are easily generated, resulting in a blockage rate of 5%-8% in the fluid cooling tank. The coolant flow rate is limited to below 0.4-0.6 m / s, which cannot effectively remove heat. At the same time, the closed structure formed after the casting solidifies makes the cooling channels difficult to clean. After long-term use, the accumulation of impurities will further aggravate the blockage, leading to a continuous decline in cooling efficiency. The motor needs to be stopped frequently for maintenance, increasing operation and maintenance costs by 30%-40%.

[0005] In terms of structural reliability and maintainability, the drawbacks of traditional cast material encapsulation are equally prominent. Cast materials are prone to aging and cracking under high temperature (>60℃) or high vibration environments, making the overall rotor structure susceptible to failure. Furthermore, the cast material is a non-removable, solidified structure; if the permanent magnet is damaged or the positioning plate malfunctions, the rotor must be cut and disassembled, resulting in repair costs 3-5 times higher than normal maintenance and repair cycles lasting several days, severely impacting water supply or production continuity. In addition, cast material-encapsulated rotors are heavy (20%-30% heavier than bolt-fixed structures), and their large moment of inertia leads to a 15%-20% higher starting current. Dynamic balance accuracy is only at G6.3 level, vibration amplitude exceeds 0.15mm during operation, and noise levels reach 70-75dB, failing to meet the low-noise and low-energy consumption requirements of industrial and civilian applications.

[0006] Traditional structures also have limitations in their adaptability to various operating conditions. The temperature tolerance of the cast material is mostly between 0-60℃, making it unsuitable for the high temperatures of deep wells (>60℃) or the frigid conditions of northern regions (<0℃). Furthermore, the rigidity of the cast material makes it prone to stress concentration cracking during high-load operation (such as exceeding rated flow and head values), leading to rotor structural damage. In harsh environments such as industrial high-temperature circulating water, the failure rate of traditional permanent magnet motor submersible pumps is 2-3 times that of those with more suitable structures, making it difficult to meet the requirements for long-term stable operation. Utility Model Content

[0007] To overcome the above-mentioned defects, the present invention provides a water-cooled submersible pump with a permanent magnet motor, which solves the technical problem of poor heat dissipation of the rotor of the permanent magnet motor in the prior art.

[0008] According to one aspect, at least one embodiment of the present invention provides a water-cooled submersible pump with a permanent magnet motor, comprising: Mounting sleeve, the mounting sleeve having a mounting cavity; A stator, wherein the stator is disposed within the mounting cavity, and the stator has a magnetic cavity; A rotor, which is disposed throughout the magnetic cavity, comprises: Positioning pieces, wherein several positioning pieces are arranged in a row, each positioning piece having a magnetic groove and a water passage hole, and having a magnetic shielding groove on its edge; A permanent magnet, wherein the permanent magnet is disposed within the magnetic steel groove; The mounting cavity is filled with coolant, which fills the water passage and is used to cool the rotor. The pump body is connected to the input end of the pump body and the output end of the rotor.

[0009] As a further technical solution, it also includes: A sliding bearing, wherein the sliding bearing is disposed at both ends of the mounting cavity; The rotor also includes a rotor shaft, which is rotatably mounted on the sliding bearing, which is used to fix the rotor shaft.

[0010] As a further technical solution, the sliding bearing is a water-lubricated graphite copper bushing.

[0011] As a further technical solution, the magnetic steel groove has four, six, or eight grooves, and the magnetic isolation groove is set in a one-to-one correspondence with the magnetic steel groove.

[0012] As a further technical solution, the water passage hole is an irregularly shaped groove.

[0013] As a further technical solution, the stator includes: An iron core having a magnetic cavity, the inner wall of which has winding grooves, the winding grooves being a plurality of those arranged circumferentially; A waterproof electromagnetic wire, wherein the waterproof electromagnetic wire has an insulating layer and is wound in the winding groove; A waterproof sleeve is provided on the outside of the waterproof electromagnetic wire, and the waterproof sleeve is made of polyester material; An insulating groove wedge is disposed in the winding groove and located at the opening of the winding groove, for pressing the waterproof electromagnetic wire.

[0014] As a further technical solution, the stator also includes: An insulating film is disposed within the winding groove and pressed tightly by the insulating groove wedge, used to cover the waterproof electromagnetic wire within the winding groove.

[0015] As a further technical solution, both the stator and the positioning piece are formed by stacking DW 270-35 high-silicon wafers.

[0016] As a further technical solution, the coolant is water.

[0017] As a further technical solution, the mounting sleeve is made of stainless steel and is designed for underwater placement.

[0018] The beneficial effects of this utility model are as follows: In this invention, the coolant is sealed within the mounting cavity, and heat dissipation is achieved through "static wrapping + dynamic flow." The specific path is as follows: the coolant fills the mounting cavity, directly wrapping the outer wall of the stator. The heat generated by the stator windings and iron core is transferred to the coolant through heat conduction, completing the outer layer heat dissipation. A portion of the coolant passes through the rotor's water passage holes, axially through the rotor's interior, carrying away the core heat of the rotor's iron core and permanent magnets. Another portion of the coolant fills the magnetic isolation grooves of the rotor's positioning plates, wrapping the rotor's edge and carrying away the eddy current heat at the rotor's edge. When the rotor rotates, the coolant in the water passage holes experiences slight flow due to centrifugal force. At the same time, the slight vibration of the submersible pump during operation also promotes the circulation of coolant between the mounting cavity and the rotor, eliminating the need for an additional pump drive and simplifying the structure.

[0019] Traditional submersible pump rotors rely solely on air or external water for indirect heat dissipation, resulting in low efficiency. In this design, the coolant directly contacts the rotor core, permanent magnets, and stator outer wall, significantly improving heat dissipation efficiency and keeping the motor operating temperature below 80°C, thus preventing demagnetization of the permanent magnets. The magnetic isolation groove simultaneously serves the dual functions of "magnetic isolation and loss reduction" and "coolant storage," eliminating the need for additional heat dissipation grooves, reducing rotor processing steps, and lowering costs. The coolant is sealed within the mounting cavity, preventing mixing with external water. Furthermore, the mounting sleeve is designed for sealing, ensuring the submersible pump can operate continuously at deep depths (e.g., 10-50 meters) without leakage risk. Simultaneously, the coolant can directly exchange heat with the outside through the mounting sleeve 1. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of this utility model and these drawings without any creative effort.

[0021] Figure 1 This is a schematic diagram of the structure in one embodiment of the present invention; Figure 2 for Figure 1 A schematic cross-sectional view of AA in the embodiment; Figure 3 for Figure 1 A cross-sectional view of BB in the embodiment.

[0022] In the diagram: Mounting sleeve-1, Mounting cavity-101, Stator-2, Magnetic cavity-202, Iron core-203, Winding groove-204, Insulating groove wedge-206, Rotor-3, Positioning plate-301, Magnet groove-302, Water passage hole-303, Magnetic isolation groove-304, Permanent magnet-306, Rotor shaft-307, Pump body-4, Sliding bearing-5. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit its scope.

[0024] To keep the drawings concise, only the parts relevant to the utility model are shown schematically in each drawing; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of the components with the same structure or function is schematically shown, or only one is labeled. In this document, "a" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0025] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, 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 utility model.

[0028] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] like Figures 1-3As shown, this invention illustrates a water-cooled submersible pump with a permanent magnet motor in one embodiment. The pump includes a mounting sleeve 1 with a mounting cavity 101. A stator 2 is disposed within the mounting cavity 101 and has a magnetic cavity 202. A rotor 3 is disposed through the magnetic cavity 202. The rotor 3 includes positioning plates 301 arranged in a plurality of configurations. Each positioning plate 301 has a magnetic groove 302 and a water passage hole 303, and its edge has a magnetic isolation groove 304. A permanent magnet 306 is disposed within the magnetic groove 302. Coolant is provided within the mounting cavity 101, filling the magnetic isolation groove 304 to cool the rotor 3. The input end of the pump body 4 is connected to the output end of the rotor 3.

[0030] In this embodiment, the mounting sleeve 1 is a hollow cylindrical shape with an internal mounting cavity 101 for accommodating the stator 2 and rotor 3. The outer wall of the stator 2 is directly welded to the inner wall of the mounting cavity 101. The mounting cavity 101 is sealed at both ends (to prevent coolant leakage) and serves as the outer channel for coolant circulation. The stator 2 has an annular structure with a magnetic cavity 202 in the center for the rotor 3 to pass through and rotate. The stator 2 windings are wound on the annular iron core and generate a rotating magnetic field when energized. When the coolant flows in the mounting cavity 101, it can directly carry away the heat from the stator windings and the iron core, preventing the stator from overheating and affecting the magnetic field strength.

[0031] The rotor 3 is an integrated component of "power output + heat dissipation channel". It is composed of several positioning plates 301 (made of stacked silicon steel sheets to reduce eddy current losses) arranged axially. Each positioning plate 301 has several magnetic steel grooves 302 evenly opened (the number is the same as the permanent magnets 306, such as 4 / 6 / 8). The permanent magnets 306 are embedded in the grooves to form a rotor magnetic field, which drives the rotor to rotate by interacting with the stator magnetic field. Water passage holes 303 are evenly opened in the center or circumference of the positioning plates 301. The water passage holes 303 of all positioning plates 301 are aligned to form an "axial water flow channel" that runs through the rotor 3. Coolant can pass through the channel to directly cool the rotor core and permanent magnets. Magnetic isolation grooves 304 (arc or rectangular) are opened on the edge of the positioning plates 301. Originally used to block the eddy current loop of the rotor core, they are additionally designed here to fill the magnetic isolation grooves 304 with coolant, wrapping the edge of the positioning plates and further removing the heat from the rotor edge, realizing dual rotor cooling of "through flow in holes + wrapping in grooves".

[0032] The permanent magnet 306 is embedded in the magnetic steel groove 302, and both ends are pressed and fixed by the positioning plates 301. The coolant surrounds the permanent magnet, which can directly remove the eddy current heat generated during operation and avoid magnetic performance decay caused by high temperature. The input end of the pump body 4 (such as the impeller shaft) is rigidly connected to the output end (rotor shaft) of the rotor 3 (key connection or flange connection). When the rotor 3 rotates, it directly drives the pump body impeller to rotate, realizing underwater water pumping without the need for additional transmission components, thus reducing power loss.

[0033] The coolant is sealed inside the mounting cavity 101 and dissipates heat through "static wrapping + dynamic flow". The specific path is as follows: the coolant fills the mounting cavity 101 and directly wraps the outer wall of the rotor 3. The heat generated by the stator winding and the iron core is transferred to the coolant through heat conduction, completing the outer layer heat dissipation; part of the coolant passes through the water passage 303 of the rotor 3 and passes through the interior of the rotor 3 axially, carrying away the core heat of the rotor iron core and permanent magnet; another part of the coolant fills the magnetic isolation groove 304 of the rotor positioning plate 301, wraps the edge of the rotor 3, and carries away the eddy current heat at the edge of the rotor 3; when the rotor 3 rotates, the coolant in the water passage 303 is slightly flowed by centrifugal force. At the same time, the slight vibration of the submersible pump during operation will also promote the circulation of coolant between the mounting cavity 101 and the rotor 2, eliminating the need for an additional pump body drive and simplifying the structure.

[0034] Traditional submersible pump rotors rely solely on air or external water for indirect heat dissipation, resulting in low efficiency. In this design, the coolant directly contacts the rotor core, permanent magnets, and stator outer wall, significantly improving heat dissipation efficiency and keeping the motor operating temperature below 80°C, thus preventing demagnetization of the permanent magnets. The magnetic isolation groove 304 simultaneously achieves the dual functions of "magnetic isolation and loss reduction" and "coolant storage," eliminating the need for additional heat dissipation grooves, reducing rotor processing steps, and lowering costs. The coolant is sealed within the mounting cavity 101, preventing mixing with external working water. Furthermore, the mounting sleeve 1 is designed for sealing, ensuring the submersible pump can operate long-term in deep water (e.g., 10-50 meters) without the risk of leakage. Simultaneously, the coolant can directly exchange heat with the outside through the mounting sleeve 1.

[0035] Furthermore, it also includes a sliding bearing 5, which is disposed at both ends of the mounting cavity 101. The rotor 3 also includes a rotor shaft 307, which is rotatably disposed on the sliding bearing 5. The sliding bearing 5 is used to fix the rotor shaft 307.

[0036] In this embodiment, a new sliding bearing 5 is added to optimize the support and sealing of the rotor shaft: the sliding bearing 5 consists of two symmetrical components, which are respectively embedded in the axial ends of the mounting cavity 101 (with interference fit or bolt fixation to the inner wall of the mounting sleeve 1); the rotor 3 adds a rotor shaft 307, which passes through the center of all positioning plates 301, and extends out of the rotor 3 body at both ends and is rotatably sleeved in the sliding bearing 5; the sliding bearing 5 is made of wear-resistant material to provide low-friction rotation support, and at the same time assists in sealing the two ends of the mounting cavity to prevent coolant leakage.

[0037] The sliding bearing 5 is fitted into the openings at both ends of the mounting cavity 101. The inner ring mates with the rotor shaft 307, and the outer ring is fixed to the inner wall of the mounting sleeve 1. The diameter of the rotor shaft 307 is designed according to the power of the submersible pump and passes through the central water passage hole 303 of all positioning plates 301 to ensure that the positioning plates 301 do not shift relative to each other when the rotor 3 rotates. The parts at both ends of the rotor shaft 307 that mate with the sliding bearing 5 are precision ground to reduce rotational friction resistance and extend the service life of the sliding bearing.

[0038] The inner ring or end face of the sliding bearing 5 is provided with a micro-flow hole to ensure that the coolant in the mounting cavity 101 can flow smoothly through the mating gap between the rotor shaft 301 and the sliding bearing 5, and is lubricated by the coolant.

[0039] Furthermore, the sliding bearing 5 is a water-lubricated graphite copper bushing.

[0040] In this embodiment, the coolant is replaced with water (clean soft water to avoid impurities clogging the channels), and the sliding bearing 5 uniformly adopts water-lubricated graphite copper sleeve (material CuSn10-Zn2+15% graphite, which combines the strength of copper and the self-lubricating properties of graphite); the two form an integrated system of "water cooling + water lubrication". Water circulates in the mounting cavity 101, rotor water passage 303, and magnetic isolation groove 304 to dissipate heat, and at the same time flows through the mating gap between the graphite copper sleeve and the rotor shaft 307 to provide lubrication for the friction pair. No additional lubricating oil is required, which is suitable for the low maintenance requirements of long-term underwater operation.

[0041] Water-lubricated graphite copper bushings use tin bronze (CuSn10-Zn2) as the base material and uniformly embed 15%-20% graphite particles. The graphite particles slowly precipitate in the water medium, forming a double-layer lubricating film of "water film + graphite film" on the inner wall of the copper bushing together with the water. The coefficient of friction is as low as 0.08-0.12 (far lower than the 0.2-0.3 of ordinary copper bushings in the water medium), and there is no abnormal noise from metal friction. The copper base material itself is resistant to fresh water corrosion, and graphite is an inert material. The combination of the two can be used for a long time in soft water (hardness ≤200mg / L, to avoid scale deposition) without the need for regular replacement of grease.

[0042] Water's specific heat capacity (4.2 kJ / (kg・℃)) is 2-3 times that of traditional insulating oil, improving heat dissipation efficiency by over 40%. It can quickly remove heat from the stator windings and rotor permanent magnets, preventing demagnetization. Furthermore, water is widely available, inexpensive, and causes no environmental pollution after leakage, making it suitable for applications with high environmental requirements, such as agricultural irrigation and aquaculture. Clean, soft water (filtered with a precision ≥50μm to remove sediment and impurities) must be used as the coolant to prevent hard water from forming scale that clogs the water passage 303 and the magnetic isolation groove 304. For long-term use, a small amount of rust inhibitor can be added to prevent corrosion of the rotor shaft 307 and copper sleeve.

[0043] During the circulation process, water circulates in the mounting cavity 101 and the water passage 303 to cool the stator, and then enters the mating gap through the copper sleeve to lubricate the friction pair. Friction lubrication is performed at the same time as the stator is cooled, without the need for additional lubrication channels.

[0044] Furthermore, the magnetic steel groove 302 has four, six, or eight grooves, and the magnetic isolation groove 304 is set in a one-to-one correspondence with the magnetic steel groove 302.

[0045] In this embodiment, the magnet slot 302 can be selected in four, six, or eight slot specifications, and the magnetic isolation slot 304 corresponds one-to-one with the magnet slot 302, so that the magnetic field design of the rotor 3 is more suitable for submersible pumps of different power. At the same time, the magnetic isolation slot 304 can accurately match the magnetic isolation and cooling requirements of each magnet, further optimizing the magnetic properties, anti-eddy current capability, and heat dissipation efficiency of the rotor, and working in conjunction with the water cooling system.

[0046] Based on the "water cooling + water lubrication graphite copper bushing", the design logic of the magnet slot 302 and the magnetic isolation slot 304 of rotor 3 is further clarified. The magnet slot 302 provides three core specifications of four slots, six slots and eight slots (to adapt to submersible pumps of different power). Each magnet slot 302 is equipped with one magnetic isolation slot 304 (i.e., the number of magnetic isolation slots = the number of magnet slots), forming a precise matching structure of "one magnet, one magnetic isolation and one cooling". This optimizes the magnetic field distribution and strengthens targeted heat dissipation, ensuring that rotor 3 can operate stably under different power scenarios.

[0047] The number of magnetic isolation slots 304 changes synchronously with the magnet slots 302 (four slots correspond to four magnetic isolation slots, and eight slots correspond to eight magnetic isolation slots), and each magnetic isolation slot 304 is set adjacent to the corresponding magnet slot 302. The function is as follows: each permanent magnet 306 has one magnetic isolation slot 304 on its outer side, which can block the eddy current loop in the rotor core along the direction of the "adjacent magnet". Compared with the traditional non-corresponding design, the eddy current loss is reduced. Especially in the high-power scenario of six or eight slots, it can effectively avoid the magnetic performance decay of the core due to eddy current overheating.

[0048] The magnetic isolation tank 304 is filled with cooling water and is adjacent to the magnet tank 302. It can directly remove the heat generated by the permanent magnet 306 during operation. In the four-tank scenario, the heat generated by the magnet in a single tank is small, and the corresponding magnetic isolation tank can meet the basic cooling needs. In the eight-tank scenario, the total heat generated by the multiple magnets is high. The eight sets of magnetic isolation tanks form a "surround cooling" system to control the temperature of each magnet below 70°C and prevent high-temperature demagnetization.

[0049] The magnetic isolation slots 304 and the magnetic steel slots 302 correspond one-to-one, making the mass distribution of the rotor 3 more uniform. The four / six / eight slots are distributed at equal angles along the circumference. When rotating, the centrifugal force is canceled out, reducing the frictional loss between the rotor shaft 307 and the graphite copper sleeve 5; avoiding vibration caused by uneven mass, and extending the service life of the graphite copper sleeve.

[0050] The more slots there are (e.g., eight slots), the more permanent magnets there are, and the greater the heat generation. The number of corresponding magnetic isolation slots 304 increases simultaneously, and the distribution of cooling water in the magnetic isolation slots 304 is more dense, which can be specifically matched to the heat dissipation needs of multiple magnets, avoiding the problem of "multiple magnets generating high heat but insufficient heat dissipation".

[0051] Furthermore, the water passage 303 is an irregularly shaped groove.

[0052] In this embodiment, the water passage 303 adopts an irregularly shaped slot structure (core shapes are waist-shaped, fan-shaped, olive-shaped, and polygonal) to replace the traditional circular hole. Through "shape optimization", it achieves a triple effect of "increasing heat dissipation area + optimizing water flow path + adapting to rotor structure", making the flow of cooling water inside the rotor 3 more efficient and the heat dissipation more uniform, further solving the problem of local overheating of high-power rotors. The shape selection of the irregularly shaped slot is based on the principle of "not weakening the strength of the positioning plate, maximizing the heat dissipation area, and adapting to the layout of the magnet slots". The three core shapes are as follows: Waist-shaped slot (most commonly used): It is "oblong" (long diameter 15-25mm, short diameter 8-12mm), opened along the radial or circumferential direction of the positioning plate, suitable for four-slot and six-slot rotors; it is easy to stamp and form, adapts to silicon steel sheet stacking process, and the heat dissipation area of ​​a single slot is larger than that of a circular hole with the same short diameter.

[0053] Sector-shaped slots (suitable for multi-slot rotors): They are "small sector-shaped" (central angle 30°-45°, radius 10-18mm), distributed around the circumference of the positioning plate, and spaced apart from the 304 magnetic steel slots of the eight-slot rotor (without interfering with the magnetic circuit); the water flow can spread evenly along the arc of the sector, covering the circumferential area of ​​the rotor and avoiding local dead zones of water flow.

[0054] Olive-shaped groove (high-power scenario): It is olive-shaped with "thick in the middle and thin at both ends" (long diameter 20-30mm, maximum short diameter 10-15mm), aligned with the axial direction of the positioning plate, and is suitable for 6-15kW high-power rotors; the water flow resistance is small, and it can pass through the rotor quickly, while preserving the structural strength of the positioning plate to the maximum extent (avoiding core breakage due to excessively large holes).

[0055] Polygonal slot (for high-power applications) is suitable for 6-15kW high-power rotors; the water flow resistance is relatively large, but it can pass through the rotor 3 relatively stably and make maximum contact with the positioning plate 301 to enhance the heat dissipation effect.

[0056] All irregularly shaped grooves are located in the non-magnetic critical area of ​​the positioning plate 301 (away from the magnetic steel groove 302 and the magnetic isolation groove 304, so as not to affect the magnetic field conduction; the number of irregularly shaped grooves on a single positioning plate is adapted to the specifications of the magnetic steel groove 304 (4-6 for a four-groove rotor and 8-10 for an eight-groove rotor) to ensure uniform water flow distribution.

[0057] Furthermore, the stator 2 includes an iron core 203, which has a magnetic cavity 202. The inner wall of the magnetic cavity 202 has a winding groove 204. The winding groove 204 is a plurality of grooves arranged in a circular pattern. The waterproof electromagnetic wire has an insulating layer and is wound in the winding groove 204. A waterproof sleeve made of polyester material is provided on the outside of the waterproof electromagnetic wire. An insulating groove wedge 206 is provided in the winding groove 204 and is located at the groove opening of the winding groove 204 for pressing the waterproof electromagnetic wire.

[0058] In this embodiment, the stator 2 is based on the iron core 203. The inner wall of the magnetic cavity 202 has circumferentially arranged winding slots 204. Waterproof electromagnetic wire with a water-resistant insulation layer is wound in the slots, and the slot openings are pressed and fixed by insulating slot wedges 206. The whole structure not only ensures the stability of the winding, but also adapts to the underwater water cooling environment through multi-layer insulation (waterproof electromagnetic wire insulation layer + slot wedge insulation) to avoid water seepage causing short circuits. At the same time, the iron core 203 and the mounting cavity 101 cooperate to achieve efficient heat dissipation, forming a double guarantee of "heat dissipation + insulation".

[0059] The iron core 203 is made of cold-rolled silicon steel sheets stacked together. It is ring-shaped with a magnetic cavity 202 at the center. Several winding slots 204 are evenly opened on the inner wall of the magnetic cavity 202. The slots are "open slots" (to facilitate the winding of waterproof electromagnetic wires). The width of the slot opening is slightly smaller than the slot body (to prevent the waterproof electromagnetic wires from falling off). Cooling water can directly remove the heat of the iron core and avoid overheating of the stacked sheets due to eddy currents (insulating varnish is applied between the stacked sheets to further reduce eddy currents).

[0060] Waterproof electromagnetic wire is selected based on its water and temperature resistance (such as polyimide enameled copper wire, with a temperature resistance of over 155℃ and water resistance conforming to GB / T4074 standard). The wire diameter is designed according to the power of the submersible pump (0.8-1.2mm for small power 0.5-1.5kW, and 1.5-2.5mm for large power 6-15kW). The waterproof electromagnetic wire is wound in the winding slot 204 according to the preset number of turns (the number of turns per slot is adjusted according to the power to ensure that the magnetic field strength matches the rotor permanent magnet). The winding connection forms a three-phase or single-phase circuit. After being energized, a rotating magnetic field is generated in the magnetic cavity 202, driving the rotor to rotate. The insulation layer of the waterproof electromagnetic wire must cover the entire circumference of the wire body. Avoid damage during winding to ensure that the insulation resistance between the wire and the iron core (grounded) and cooling water is ≥50MΩ. At the same time, a waterproof sleeve is set on the outside. The waterproof sleeve is made of polyester film, which has good heat dissipation and is not easily damaged by temperature changes.

[0061] The insulating slot wedge 206 is embedded in the slot of the winding slot 204 to press the waterproof electromagnetic wire in the slot tightly, so as to prevent the winding from shifting due to vibration when the motor is running; it blocks the direct contact between the waterproof electromagnetic wire and the cooling water in the magnetic cavity 202, and isolates the waterproof electromagnetic wire from the iron core to prevent short circuits after the insulation layer is damaged.

[0062] Furthermore, the stator 2 also includes an insulating film, which is disposed in the winding groove 204 and pressed by the insulating groove wedge 206 to cover the waterproof electromagnetic wire in the winding groove 204.

[0063] In this embodiment, an insulating film is added to the stator winding structure to further enhance the insulation reliability in the underwater environment. The insulating film completely covers the waterproof electromagnetic wire in the winding slot, fills the gap between the waterproof electromagnetic wire and the slot wall, avoids insulation failure caused by winding vibration and wear, and is compatible with the water cooling system to ensure that the stator has no short circuit risk during long-term underwater operation.

[0064] The insulating film must meet four core requirements: water resistance, temperature resistance, wear resistance, and high insulation. The recommended options are: Polyimide composite film (preferred for high-power applications): made of polyimide base film (temperature resistance above 220℃) composite with polyester film, thickness 0.05-0.1mm, breakdown voltage ≥15kV / mm, dielectric loss ≤0.005, insulation resistance ≥100MΩ after long-term immersion in water (3 months), and resistant to friction during waterproof electromagnetic wire winding (surface hardness Shore D80+); Nomex insulating paper (suitable for low-to-medium power applications): made of aromatic polyamide fiber, thickness 0.1-0.2mm, with certain flexibility, can tightly adhere to the inner wall of the winding groove, temperature resistance 180℃, excellent water resistance (water absorption expansion rate ≤1%), and cost 30% lower than polyimide composite film.

[0065] The insulation film is only 0.05-0.2mm thick, with low thermal resistance (≤0.01℃・m2 / W). The heat generated by the waterproof electromagnetic wire can be quickly conducted to the iron core 203 through the insulation film, and then carried away by the cooling water in the mounting cavity 101, which has little impact on the heat dissipation efficiency of the stator. The insulation film is a non-magnetic material (relative permeability ≈1), which will not interfere with the magnetic field transmission between the stator winding and the rotor permanent magnet, and the magnetic field strength remains stable.

[0066] Furthermore, both the stator 2 and the positioning piece 301 are formed by stacking DW270-35 high-silicon wafers.

[0067] In this embodiment, DW270-35 is a cold-rolled non-oriented silicon steel sheet (also known as electrical steel), and its core parameters and characteristics are as follows: Composition and specifications: silicon content approximately 3.0%-3.5% (high silicon content), thickness 0.35mm (thin specification), iron loss value P15 / 50=2.70W / kg (i.e., iron loss at 50Hz frequency and 1.5T magnetic flux density), permeability ≥1.8×10 4 H / m (high permeability ensures efficient magnetic field transmission); core advantages: high silicon content increases material resistivity (approximately 50 μΩ·cm, more than 3 times that of ordinary low carbon steel), significantly suppressing eddy current generation; thin-gauge laminates (0.35 mm) shorten the eddy current path, further reducing eddy current losses; the combination of these two factors reduces iron loss by 30%-40% compared to ordinary silicon steel sheets (such as DW350-50).

[0068] Both the stator core 203 and the positioning piece 301 adopt the "multi-layer silicon steel sheet lamination" process (lamination coefficient ≥ 0.95): each layer of silicon steel sheet is coated with an inorganic insulating coating (thickness 0.5-1μm) to block the conductive path between layers and avoid the formation of large eddy current loops; after lamination, it is fixed by rivets to ensure the overall structural strength (bending strength ≥ 200MPa) and adapt to the underwater vibration environment of submersible pumps.

[0069] When the stator winding is energized to generate an alternating magnetic field, the low hysteresis loss of DW270-35 (accounting for 40%-50% of iron loss) can reduce the heating of the iron core itself. Combined with the water cooling of the mounting cavity 101, the temperature of stator 2 is reduced by 8-12℃ compared to using ordinary silicon steel sheets. The high permeability ensures that the stator iron core can conduct magnetism efficiently, reducing the excitation current (reducing the excitation current by 15%-20%), improving the motor power factor (cosφ≥0.9), and meeting the "low energy consumption, high output" requirements of submersible pumps.

[0070] When the rotor 3 rotates, the rotating magnetic field of the stator 2 will induce eddy currents in the positioning plate 301. The high resistivity of DW270-35 can reduce eddy current losses by more than 50%, avoiding overheating of the positioning plate (temperature ≤65℃). The hardness of the high silicon steel sheet (HV180-220) is higher than that of ordinary silicon steel. After being stacked, it can stably maintain the shape of the magnetic shielding groove 304, ensuring that the magnetic shielding and cooling functions are not affected by deformation. At the same time, the heat reduced by the low iron loss characteristics can reduce the heat dissipation load of the cooling water in the magnetic shielding groove and improve the overall cooling efficiency.

[0071] Furthermore, the coolant is water.

[0072] In this embodiment, water as a coolant perfectly matches the submersible pump's integrated "water cooling + water lubrication" design. It utilizes water's high specific heat capacity to achieve efficient heat dissipation and works in conjunction with the water-lubricated graphite copper sleeve to provide lubrication. It also has the advantages of being environmentally friendly, low-cost, and readily available. Furthermore, it is compatible with components such as stator insulation structure and DW270-35 silicon steel sheets, with no risk of corrosion or blockage, making it the optimal choice for underwater operation scenarios.

[0073] Furthermore, the mounting sleeve 1 is made of stainless steel and is designed for underwater placement.

[0074] In this embodiment, the mounting sleeve 1 is made of stainless steel (304 or 316 is recommended), which is designed to meet the requirements of long-term underwater operation. It not only avoids underwater rusting through excellent corrosion resistance, but also supports internal components such as stator and rotor with high strength. At the same time, it is compatible with water cooling system and sealing design to ensure bidirectional sealing of the mounting cavity 101 (preventing external water infiltration and internal coolant leakage), further enhancing the underwater reliability of the submersible pump.

[0075] In summary, the windings in this design utilize 468-grade permanent magnet motor windings made of oxygen-free copper, with a three-layer protective coating (insulating varnish + polyester film + insulating nylon), providing excellent waterproof, temperature resistance, and voltage resistance. The silicon steel sheets used are DW270-35 high-silicon wafers, laminated together, resulting in high permeability, high magnetic flux density, and low iron loss (P15 / 50 = 2.70 W / kg). The magnets are selected from three grades: N35SH, N42SH, and N45SH, with a maximum operating temperature of 150℃ and a maximum magnetic energy level of 13.3 kA / mm². The rotor's outer edge features 4 / 6 / 8 magnetic isolation slots (matching the number of magnetic poles to prevent magnetic short circuits), and the rotor is punched with 4 / 6 / 8 magnet slots (corresponding to the number of magnets) and irregularly shaped water holes (for heat dissipation).

[0076] Cooling System: Employs water-filled cooling (water as coolant), with its own heat dissipation channels, eliminating the risk of oil contamination and solving the pain point of oil leakage leading to well failure in traditional oil-filled submersible pumps; Housing Material: The motor housing is made of 304 stainless steel, offering excellent corrosion resistance (corrosion rate in freshwater environments ≤0.01mm / year) and an attractive appearance, suitable for long-term underwater operation; Power Limit: The water-filled design breaks through power limitations, reaching a maximum of 200kW, far exceeding the 7.5kW limit of traditional oil-filled submersible pumps, meeting the demand for high-power water pumping.

[0077] The motor drive is further enhanced by frequency conversion, employing a dedicated frequency converter for permanent magnet motors. The starting current rises in a sloping manner to the rated current, with the starting current being 0 times the rated current, eliminating grid impact (traditional motors have a direct starting current of 4-7 times the rated current, autotransformer starting is 4 times, and soft starting is 2-3 times). It features constant current output: With constant current drive function, even with voltage fluctuations (from 380V to 280V for three-phase, and from 220V to 120V for single-phase), the current is locked at the motor's rated value, avoiding the vicious cycle of "voltage drop → current rise → overload burnout / magnet demagnetization." It also boasts wide voltage adaptability: It can operate normally with three-phase 280-380V and single-phase 120-220V without the need for an additional voltage regulator, adapting to unstable voltage scenarios and international operations.

[0078] Compared to traditional oil-filled submersible pumps, the core advantages are as follows: 1. Pollution risk: No oil leakage pollution problem, ensuring the safety of well water quality; oil leakage in traditional oil-filled pumps will render the well unusable; 2. Maintenance cost: Only periodic replenishment of cooling water is required (evaporation loss), eliminating the cost of oil replacement and frequent replacement of seals; traditional oil-filled pumps require frequent and costly maintenance; 3. Magnet lifespan: 150℃ temperature resistant design + constant current overload protection, magnet lifespan reaches 8-10 years; traditional oil-filled pumps, due to uneven oil heat dissipation, are prone to magnet demagnetization, with a lifespan of about 5 years.

[0079] Typical application scenarios include drinking water wells and agricultural irrigation (ensuring water quality safety, 304 stainless steel is corrosion resistant); large-scale water conservancy projects and mine drainage (200kW high power to adapt to large flow and high head requirements); remote areas and cross-border operations (wide voltage adaptability to cope with voltage instability or different voltage standards); and mild corrosion scenarios (such as coastal areas and light industrial wastewater, which can be upgraded to 316 stainless steel shell).

[0080] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A water-cooled submersible pump with a permanent magnet motor, characterized in that, include: Mounting sleeve (1), the mounting sleeve (1) having a mounting cavity (101); Stator (2), the stator (2) is disposed in the mounting cavity (101), the stator (2) has a magnetic cavity (202); Rotor (3), which is disposed through the magnetic cavity (202), the rotor (3) comprising: Positioning piece (301), wherein several positioning pieces (301) are arranged in a row, wherein the positioning piece (301) has a magnetic groove (302) and a water passage hole (303), and the edge has a magnetic isolation groove (304). A permanent magnet (306) is disposed within the magnetic steel groove (302); The mounting cavity (101) is filled with coolant, which fills the water passage (303) to cool the rotor (3). Pump body (4), the input end of the pump body (4) is connected to the output end of the rotor (3).

2. The water-cooled submersible pump with a permanent magnet motor according to claim 1, characterized in that, Also includes: A sliding bearing (5) is disposed at both ends of the mounting cavity (101); The rotor (3) also includes a rotor shaft (307), which is rotatably mounted on the sliding bearing (5) for fixing the rotor shaft (307).

3. A water-cooled submersible pump with a permanent magnet motor according to claim 2, characterized in that, The sliding bearing (5) is a water-lubricated graphite copper bushing.

4. A water-cooled submersible pump with a permanent magnet motor according to claim 1, characterized in that, The magnetic steel groove (302) has four, six, or eight grooves, and the magnetic isolation groove (304) is provided in a one-to-one correspondence with the magnetic steel groove (302).

5. A water-cooled submersible pump with a permanent magnet motor according to claim 1, characterized in that, The water passage (303) is an irregularly shaped groove.

6. A water-cooled submersible pump with a permanent magnet motor according to claim 1, characterized in that, The stator (2) includes: The iron core (203) has the magnetic cavity (202), and the inner wall of the magnetic cavity (202) has winding grooves (204), which are a plurality of grooves arranged in a circular pattern; Waterproof electromagnetic wire, wherein the waterproof electromagnetic wire has an insulating layer and is wound in the winding groove (204); A waterproof sleeve is provided on the outside of the waterproof electromagnetic wire, and the waterproof sleeve is made of polyester material; An insulating groove wedge (206) is disposed in the winding groove (204) and located at the opening of the winding groove (204) for pressing the waterproof electromagnetic wire.

7. A water-cooled submersible pump with a permanent magnet motor according to claim 6, characterized in that, The stator (2) also includes: An insulating film is disposed in the winding groove (204) and pressed by the insulating groove wedge (206) to cover the waterproof electromagnetic wire in the winding groove (204).

8. A water-cooled submersible pump with a permanent magnet motor according to claim 1, characterized in that, Both the stator (2) and the positioning piece (301) are formed by stacking high silicon wafers of DW 270-35.

9. A water-cooled submersible pump with a permanent magnet motor according to claim 1, characterized in that, The coolant is water.

10. A water-cooled submersible pump with a permanent magnet motor according to claim 1, characterized in that, The mounting sleeve (1) is made of stainless steel and is used for underwater placement.

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