An outward turning compact pipeline centrifugal pump and a method of manufacturing the same

Abstract

The application discloses an outer rotating compact pipeline centrifugal pump and a manufacturing method thereof. The pump comprises a pump body, a fluid cavity is formed in the pump body, and a water inlet and a water outlet are arranged on the pump body and communicated with the fluid cavity. The outer rotating compact pipeline centrifugal pump further comprises an iron core stator fixedly installed in the pump body, a shaft assembled at the center of the inner circle of the iron core stator and having one end extended from the iron core stator, an impeller arranged in the fluid cavity and connected with the one end of the shaft, and a magnetic steel rotor fixedly connected with the impeller and synchronously rotated with the impeller. The magnetic steel rotor is located at the outer circumferential side of the iron core stator and has a radial air gap H left between the magnetic steel rotor and the iron core stator to form an outer rotating radial magnetic flux motor structure. The electromagnetic force generated by the outer rotating radial magnetic flux motor structure drives the impeller to rotate, and under the rotation of the impeller, fluid medium is sucked from the water inlet and discharged from the water outlet.

Description

Technical Field

[0001] This invention relates to a pipeline centrifugal pump and its manufacturing method, and more particularly to an externally rotating compact pipeline centrifugal pump and its manufacturing method, belonging to the technical field of spindle-supported centrifugal pump manufacturing. Background Technology

[0002] As a core device for fluid transport, inline centrifugal pumps are widely used in industrial cooling, HVAC, automotive electronics, and various civil systems. With the trend towards miniaturization and high integration in modern equipment, internal installation space is often severely limited, thus placing increasingly stringent requirements on the overall compactness of centrifugal pumps (including radial and axial dimensions).

[0003] Traditional centrifugal pumps typically employ a separate motor and pump body design or an axially directly connected design, resulting in an excessively long overall axial dimension. To shorten the pump's axial length, existing technologies utilize pumps based on a disc-type motor structure. For example, Chinese invention patent CN110486298A, published on November 22, 2019, discloses a vortex hydrogen circulation pump based on a disc-type motor structure. This pump includes: a motor housing with a rear end cover connected to the rear end and a vortex front end cover connected to the front end; and a vortex rotor positioned between the motor housing and the vortex front end cover, with the rotor blades forming a... An annular flow channel; a motor spindle, with its two ends respectively mounted on the rear end cover and the front end cover of the vortex rotor, the vortex rotor being fixed to the motor spindle by bearings; a motor stator, the motor stator being press-fitted onto the rear end cover of the motor; a motor rotor, the motor rotor being several permanent magnets fixed on the vortex rotor; an explosion-proof coating, the explosion-proof coating being wrapped around the outside of the motor stator and the permanent magnets; an air inlet and an air outlet, the air inlet and air outlet being located on the motor housing or the front end cover of the vortex rotor, air entering from the air inlet, rotating and pressurizing along the annular flow channel, and then exiting from the air outlet.

[0004] While this design allows for a shorter axial dimension, it introduces new spatial layout contradictions and potential mechanical instability issues. Firstly, in disc motor structures, the coils wound around the motor stator are typically arranged along a radial plane. This structural characteristic inevitably results in the stator and rotor occupying a large area in the radial plane, significantly increasing the radial space of the pump body and making it difficult to adapt to slender or narrow installation environments. Secondly, in centrifugal pumps driven by disc motors, the impeller and motor rotor are usually arranged in series or end-face contact along the main shaft direction. This transmission layout results in a large bearing span supporting the main shaft, and the impeller's center of gravity deviates significantly from the effective support center of the bearing, creating a pronounced "cantilever effect." When the pump operates at high speed and is subjected to complex fluid loads, the cantilevered end of the main shaft is prone to high-frequency wobbling and vibration. This not only causes significant noise but also accelerates the failure of bearings and seals, severely shortening the service life of the centrifugal pump.

[0005] In addition, to overcome the drawback of excessive radial dimensions in disc motors, there have been attempts in the industry to apply conventional radial flux motors to pumps. For example, Chinese invention patent application CN119727184A, published on March 28, 2025, discloses a radial flux electric motor, comprising: a stator having a radially inner stator surface; and a rotor mounted inside the stator, defining a rotation axis, and having axially opposite rotor ends and a radially outer rotor surface positioned near the radially inner stator surface, thereby establishing an air gap between the radially inner stator surface and the radially outer rotor surface; wherein the rotor includes a fluid circulation arrangement having at least one fluid channel extending through the rotor to the radially outer rotor surface and configured to receive liquid via a first passage and gas via at least one second passage, and when the rotor rotates sufficiently inside the stator, the liquid and gas are guided into the air gap by centrifugal force to discharge the liquid and gas at the axially opposite ends of the rotor, thereby cooling the electric motor.

[0006] Such pumps typically employ an internal rotor structure, where the rotor is mounted inside a stator with a radial inner stator surface. However, when this traditional internal rotor radial flux motor is combined with the pump, the main shaft is forced to simultaneously perform the dual functions of "drive transmission" and "positioning support." The electromagnetic drive force generated inside the motor must first be transmitted to the internal rotor, which then twists the main shaft, which in turn drives the impeller to rotate against fluid resistance. This means that the main shaft must constantly withstand the combined stress of high-intensity "torque" and "bending" caused by fluid impact during operation; stress concentration is easily generated during high-speed start-up and shutdown or drastic fluctuations in fluid load, leading to fatigue, loosening, or even failure of connecting parts. Furthermore, this "inside-out" center-drive mode has a short torque arm and poor resistance to fluid impact, severely restricting the design of equipment towards lightweight and miniaturization.

[0007] In summary, existing spindle-supported centrifugal pumps suffer from a trade-off in their structural design: using a disc motor increases the radial dimension and introduces cantilever vibration; while using a conventional internal rotor radial flux motor exposes the spindle to complex combined forces and transmission fatigue bottlenecks. Therefore, designing a highly stable pipeline centrifugal pump that can drastically reduce volume and weight while fundamentally reconstructing the power transmission path and "unloading" the spindle, completely decoupling its driving and positioning support functions, and thus eliminating the risk of mechanical fatigue, has become the urgent technical problem this invention aims to solve. Summary of the Invention

[0008] The technical problem to be solved by this invention is to address the deficiencies in the existing technology by providing an externally rotating compact pipeline centrifugal pump and its manufacturing method. It adopts an externally rotating radial flux motor structure. In the technical field of spindle-supported centrifugal pumps, it not only minimizes the space volume and weight, but also fundamentally reconstructs the power transmission path, realizing the "unloading" of the spindle and completely decoupling the driving function and positioning support function of the spindle, thereby eliminating the potential mechanical fatigue of the spindle and improving stability.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: an externally rotating compact pipeline centrifugal pump, comprising: a pump body having a fluid cavity formed inside, and an inlet and an outlet communicating with the fluid cavity on the pump body; the externally rotating compact pipeline centrifugal pump further comprising: an iron core stator fixedly installed in the pump body; a shaft assembled at the inner circle center of the iron core stator, and one end of the shaft extending out from the iron core stator; an impeller disposed in the fluid cavity and connected to one end of the shaft; and a magnetic rotor fixedly connected to the impeller and rotating synchronously with the impeller; wherein, the magnetic rotor is located on the outer periphery of the iron core stator, and a radial air gap H is left between the magnetic rotor and the iron core stator to form an externally rotating radial flux motor structure; the electromagnetic force generated by the externally rotating radial flux motor structure drives the impeller to rotate, and under the rotation of the impeller, the fluid medium is drawn in from the inlet and discharged from the outlet.

[0010] Preferably, the magnet rotor includes an annular sidewall and magnets disposed on the inner circumferential surface of the annular sidewall; the bottom end of the annular sidewall is fixed to the top surface of the impeller, so that the magnet rotor and the impeller form an integral shell-like structure with one side opening, and the shell-like structure is fitted over the outside of the iron core stator.

[0011] Preferably, a top plate and a bottom plate are provided in the fluid cavity of the pump body, and a support sleeve is provided between the top plate and the bottom plate. The inner circumferential surface of the iron core stator is sleeved on the outer circumferential surface of the support sleeve. The shaft is assembled in the inner cavity of the support sleeve, and one end of the shaft extends out from the support sleeve. A shielding sleeve is also provided between the top plate and the bottom plate and at the position of the outer circumferential surface of the support sleeve. The top plate, the bottom plate, the support sleeve and the shielding sleeve together form a completely closed encapsulated space B. The iron core stator and the coil wound on it are located in the encapsulated space B, and the encapsulated space B is filled with insulating glue.

[0012] Preferably, the pump body includes a pump casing and a cylindrical outer casing, the bottom end of the outer casing contacts the top of the pump casing, and the top end of the outer casing contacts the top plate; the top plate, the outer casing, and the pump casing are connected together by bolts passing through the top plate and the pump casing.

[0013] Preferably, the shaft is rotatably connected to the inner cavity of the support sleeve via a bearing, and the impeller is fixedly connected to one end of the shaft.

[0014] Preferably, the shaft is fixedly connected to the inner cavity of the support sleeve, and the impeller is rotatably connected to one end of the shaft via a bearing.

[0015] Preferably, one end of the shaft is provided with a protruding end, and the center of the impeller is provided with a groove that matches the shape of the protruding end; the protruding end is an inverted frustum-shaped cone that is larger at the top and smaller at the bottom, and the groove is a conical groove; during assembly, the protruding end is inserted into the groove and screwed into the end face of the protruding end by a mounting screw that passes through the baffle, and the baffle is used to press the impeller against the shaft end step on one end of the shaft, thereby fixing the impeller to one end of the shaft.

[0016] Preferably, the central axes of the inlet and outlet are perpendicular to each other or parallel to each other.

[0017] The present invention also discloses a method for manufacturing an externally rotating compact pipeline centrifugal pump as described above, characterized by comprising the following steps: S1. First, fix the top of the support sleeve to the bottom surface of the top plate, then fit the iron core stator with the coil onto the outer circumference of the support sleeve; pass the power line of the coil on the iron core stator through the wire hole of the top plate; fix the bottom plate to the bottom end of the support sleeve, fit the shielding sleeve between the top plate and the bottom plate and fix both ends to form a completely closed glue seal space B. S2. Fill the sealing space B with adhesive, and then cure it after filling. S3. After curing, assemble the shaft in the inner cavity of the support sleeve so that one end of the shaft extends out from the bottom of the support sleeve. S4. First, fix the magnet rotor and impeller into one piece, and then assemble the impeller onto one end of the shaft, so that the magnet rotor is located on the outer periphery of the iron core stator and leaves a radial air gap H, so as to form an external rotation radial flux motor structure. S5. Fit the outer casing onto the outer periphery of the externally rotating radial flux motor structure, and connect the top plate, outer casing, and pump casing together using bolts.

[0018] Preferably, the potting process in step S2 adopts a combination of step-by-step potting and alternating vacuuming, specifically: first, a portion of the volume of insulating adhesive is poured into the sealing space B, followed by vacuuming to remove internal air bubbles; then, a portion of the volume of insulating adhesive is poured in again and vacuumed again; this process is repeated until the insulating adhesive completely fills the sealing space B, and finally, curing is performed.

[0019] The beneficial effects of this invention are as follows: Through its unique spatial layout, this invention effectively overcomes the spatial limitations of traditional centrifugal pumps and disc-type motor-driven pumps, achieving a significant reduction in overall size and weight. Simultaneously, the invention achieves complete decoupling and "unloading" of the main shaft function: this "unloading" design completely eliminates the potential mechanical fatigue risks caused by the main shaft simultaneously bearing torsional and bending stresses under complex fluid resistance. Through a reverse-wrapping nested design, the overall center of gravity of the rotating component (the combination of the magnet rotor and impeller) is significantly moved closer to the shaft's support center, greatly improving the coincidence between the center of gravity and the geometric center. This perfectly counteracts the eccentric torque generated under high-speed operation and fluid impact, making rotation more stable and completely solving the problems of high-frequency wobbling and easy bearing wear caused by the "cantilever effect" of the main shaft in existing technologies. The use of a process combining step-by-step potting and alternating vacuuming allows the air trapped inside the insulating adhesive and in the bottom gaps to rapidly expand and float to the liquid surface under vacuum negative pressure, effectively removing the air from the sealed space B. This fundamentally eliminates internal condensation caused by temperature fluctuations during operation. Simultaneously, the bubble-free solid insulator provides an excellent thermal bridge, allowing heat generated by the coil to be transferred to the shielding sleeve without thermal resistance, significantly improving water cooling efficiency. The "conical mating" structure utilizes the progressive guidance and self-centering principle of the conical surface for impeller and shaft assembly, completely resolving component misalignment and jamming issues caused by magnetic adsorption, and avoiding the risk of scratches to the anti-corrosion coating on the stator and rotor surfaces from repeated insertion and removal. Thanks to the self-centering function of the conical surface, operators no longer need to perform meticulous manual alignment, achieving "one-click" blind assembly, greatly reducing assembly difficulty and significantly improving assembly efficiency on the production line. After final tightening, the tight fit between the conical surfaces not only eliminates radial assembly gaps but also ensures a high degree of concentricity between the impeller and shaft system, further reducing eccentric vibration during equipment operation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the axial cross-sectional structure of Embodiment 1 of the present invention; Figure 2 for Figure 1 Enlarged structural diagram of section A in the middle; Figure 3 This is a schematic diagram of the axial cross-sectional structure of the magnetic rotor and impeller in Embodiment 1 of the present invention; Figure 4 for Figure 1 A schematic diagram of a partial axial cross-section of the structure located at the stator of the iron core; Figure 5 This is a schematic diagram of the manufacturing principle steps of Embodiment 1 of the present invention. Figure 1 ; Figure 6 This is a schematic diagram of the manufacturing principle steps of Embodiment 1 of the present invention. Figure 2 ; Figure 7 This is a schematic diagram of the manufacturing principle steps of Embodiment 1 of the present invention. Figure 3 ; Figure 8 for Figure 7 A schematic diagram of a partial axial cross-section of the structure located at the impeller; Figure 9 This is a partial axial cross-sectional view of the structure located at the impeller in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram of the axial cross-sectional structure of Embodiment 4 of the present invention; In the diagram: 1. Pump body; 111. Pump casing; 2. Fluid chamber; 3. Inlet; 4. Outlet; 5. Iron core stator; 6. Shaft; 611. Protruding end; 612. Shaft end stepped portion; 7. Impeller; 711. Groove portion; 8. Magnet rotor; 811. Annular sidewall; 812. Magnet; 9. Top plate; 10. Bottom plate; 11. Support sleeve; 112. Positioning stop; 12. Coil; 13. Shielding sleeve; 14. Insulating adhesive; 15. Bolt 1; 16. Bearing; 17. Oil seal; 18. Top cover; 19. Clamping sleeve; 20. Bearing positioning stop; 21. Assembly screw; 22. Baffle. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: As Figure 1 and Figure 2 As shown, an externally rotating compact pipeline centrifugal pump includes: a pump body 1, with a fluid cavity 2 formed inside, and an inlet 3 and an outlet 4 communicating with the fluid cavity 2 on the pump body 1; an iron core stator 5, fixedly installed inside the pump body 1; a shaft 6, rotatably connected to the center of the inner circle of the iron core stator 5 via a bearing 16, and one end of the shaft 6 extending out from the iron core stator 5; an impeller 7, fixedly connected to the extended end of the shaft 6 and located inside the fluid cavity 2; and a magnetic rotor 8, fixedly connected to the impeller 7 and moving with the impeller 7. The rotor rotates in a step; wherein the magnetic steel rotor 8 is located on the outer periphery of the iron core stator 5, and a radial air gap H is left between it and the iron core stator 5 to form an external rotation radial flux motor structure; when the iron core stator 5 is energized, the peripheral magnetic steel rotor 8 and impeller 7 are directly driven to rotate by electromagnetic force, so that the shaft 6 is decoupled from the radial flux motor drive function, and the shaft 6 only serves as the positioning and support shaft for the rotation of the impeller 7. Under the rotation of the impeller 7, fluid media such as water and oil are drawn in from the inlet 3 and discharged from the outlet 4.

[0023] Unlike existing designs that use disc-type motor structures, resulting in excessively large radial dimensions, this invention employs an externally rotating radial flux motor structure. The iron core stator 5 is fixed inside the pump body 1, while the magnetic rotor 8 is located on the outer periphery of the iron core stator 5. This structure allows the motor stator and rotor to not only be compactly nested radially but also directly integrated into the pump body's own cavity, highly merging the spaces that were originally two independent systems (drive motor system and fluid pumping system), significantly reducing the overall cross-sectional area of ​​the machine. Furthermore, since the magnetic rotor 8 is directly fixed to the impeller 7 and rotates synchronously with it, and the support shaft 6 is directly embedded in the stator center, it completely eliminates the need for couplings, long transmission cantilever shafts, and redundant external support housings required by traditional split-type motors or internal rotor motors. This not only fundamentally reduces the physical boundaries of the equipment but also significantly lowers the overall weight, achieving true lightweight and miniaturized design. Additionally, the internal cavity of a traditional motor stator, without an internal rotor, typically becomes an unusable "dead space," unnecessarily increasing the equipment's volume. This invention ingeniously assembles the shaft 6 at the center of the inner circle of the iron core stator 5, achieving a complete physical overlap between the installation space of the shaft 6 and the inner cavity space of the iron core stator 5. This design fully activates and utilizes the previously unused internal dead space, perfectly accommodating the main shaft support components without adding any extra external dimensions, thereby further minimizing the overall axial and radial dimensions of the pump body. Therefore, the externally rotating compact pipeline centrifugal pump proposed in this embodiment, through its unique spatial layout, effectively overcomes the spatial limitations of traditional centrifugal pumps and disc motor driven pumps, achieving a drastic reduction in overall size and weight.

[0024] Furthermore, as mentioned in the background section, in radial flux electric motors, the power transmission path is "electromagnetic force - internal rotor - main shaft - impeller". In this embodiment, when the iron core stator 5 is energized, the electromagnetic force directly drives the peripheral magnetic rotor 8. Since the magnetic rotor 8 is directly fixed to the impeller 7, the driving force is directly transmitted to the impeller 7, realizing direct drive from the outside to the inside. At this time, the shaft 6 no longer needs to transmit any torque; it only serves as a positioning and support shaft for the rotation of the impeller 7. The complete decoupling and "unloading" of the main shaft function completely eliminates the mechanical fatigue risk caused by the main shaft bearing torsional and bending stresses simultaneously under complex fluid resistance. In addition, the external magnetic rotor 8 has a larger rotation radius (i.e., a larger torque arm) compared to the traditional internal rotor, which gives the impeller 7 stronger resistance to fluid impact. Even under conditions of high-speed start-stop or severe fluctuations in fluid load, the equipment can still maintain extremely high operational stability and extremely long mechanical life.

[0025] like Figures 1 to 3As shown, the magnet rotor 8 includes an annular sidewall 811 and a magnet 812 disposed on the inner circumferential surface of the annular sidewall 811; the annular sidewall 811 can be made of iron ring, and the magnet 812 is glued to the inner circumferential surface of the annular sidewall 811. The bottom end of the annular sidewall 811 is fixed to the top surface of the impeller 7, thereby making the magnet rotor 8 and the impeller 7 form an integral one-sided open cover-like structure, and the cover-like structure is fitted and covers the outside of the iron core stator 5. In traditional pump structures, the impeller is often located at the cantilever end of the shaft, with the center of gravity shifting outward. In this embodiment, the integrated shell-like structure composed of the magnet rotor 8 and the impeller 7 encloses the iron core stator 5 inside. This reverse-encasing nested design causes the overall center of gravity of the rotating component (the combination of the magnet rotor and the impeller) to move significantly closer to the support center of the shaft 6. The coincidence between the center of gravity and the geometric center is greatly improved, perfectly offsetting the eccentric torque generated under high-speed operation and fluid impact, making the rotation more stable, and completely solving the problems of high-frequency wobbling of the main shaft and easy wear of bearings caused by the "cantilever effect" in the prior art.

[0026] In this embodiment, the externally rotating radial flux motor and the pipeline centrifugal pump are deeply integrated. During operation, the fluid medium (such as water or oil) flowing through the fluid chamber 2 can directly carry away the heat generated during motor operation, achieving efficient "built-in liquid cooling" heat dissipation. This design completely eliminates the need for external cooling fans and heat sinks required by traditional motors, thereby further reducing the overall size and operating noise. However, this integrated pump-machine structure also brings a new technical challenge. Since the iron core stator is directly placed inside the fluid chamber, conductive or corrosive fluid media can easily come into direct contact with the iron core stator and the coils wound around it, leading to serious risks of leakage, short circuits, or insulation corrosion failure. Based on this, in order to completely solve the insulation and protection hazards caused by the above-mentioned fluid contact, this embodiment further proposes a highly efficient isolation insulation protection structure for the iron core stator and coils. Figure 1 and Figure 4As shown, a circular top plate 9 and a bottom plate 10 are provided inside the fluid cavity 2 of the pump body. A support sleeve 11 is provided between the top plate 9 and the bottom plate 10. The central axes of the top plate 9, the bottom plate 10, and the support sleeve 11 coincide with each other. The internal space of the support sleeve 11 is a shaft assembly space. The inner circumferential surface of the iron core stator 5 is fitted onto the outer circumferential surface of the support sleeve 11. The length of the coil 12 wound in the iron core stator 5 is arranged axially. A support sleeve 11 is also provided between the top plate 9 and the bottom plate 10 and located on the outer circumferential surface of the support sleeve 11. A shielding sleeve 13 is provided, preferably made of non-magnetic or weakly magnetic and corrosion-resistant materials such as stainless steel. Thus, the top plate 9, bottom plate 10, support sleeve 11, and outer shielding sleeve 13 together form a completely sealed encapsulated space B. The iron core stator 5 and coil 12 are both located within this encapsulated space B, which is completely encapsulated and filled with insulating glue 14, thereby providing insulation protection for the iron core stator and coil. This embodiment achieves absolute water-blocking isolation at the physical level by setting up the encapsulated space B, while the filled insulating glue 14 completely eliminates air within the encapsulated space B, preventing condensation during temperature fluctuations. The combination of these two elements provides double protection for the iron core stator 5 and coil 12, completely eliminating the risk of leakage and short circuits even under extreme conditions of long-term high-pressure immersion. In addition, the insulating adhesive 14 injected in this structure serves as an excellent thermal conductive medium, which can conduct the heat generated by the coil 12 to the shielding sleeve 13 with low resistance. At the same time, the outer surface of the shielding sleeve 13 is in direct contact with the fluid medium that is continuously circulated in the fluid cavity 2. When the fluid medium flows, it carries away a large amount of heat, thus providing the stator with a highly efficient "liquid cooling" system.

[0027] like Figure 1 As shown, the pump body 1 includes a pump casing 111 and a cylindrical outer casing 112. The bottom end of the outer casing 112 contacts the top of the pump casing 111, and the top end of the outer casing 112 contacts the top plate 9. A bolt 15 is used to pass through the top plate 9 and the pump casing 111 and then lock them together, thus connecting the top plate 9, the outer casing 112, and the pump casing 111. The interior of the top plate 9, the outer casing 112, and the pump casing 111 encloses a fluid cavity 2. The inlet 3 and the outlet 4 are both located on the pump casing 111. In this embodiment, the central axes of the inlet 3 and the outlet 4 are perpendicular to each other. This arrangement allows the fluid medium to be drawn in axially from the impeller center, and after being worked by the high-speed rotating blades, it is radially ejected under centrifugal force. This avoids unnecessary sharp bends and backflows of the fluid inside the pump casing, significantly reducing local resistance loss and turbulence, thereby improving the overall suction efficiency and head of the pump.

[0028] This embodiment also discloses a method for manufacturing an external rotary compact pipeline centrifugal pump, the steps of which are as follows: S1, such as Figure 5As shown, firstly, the top end of the support sleeve 11 is welded to the bottom surface of the top plate 9, so that the support sleeve 11 coincides with the central axis of the top plate 9. Then, the iron core stator 5 with coil is sleeved onto the outer circumferential surface of the support sleeve 11. A stepped positioning stop 112 is provided on the outer circumferential surface of the support sleeve 11. When the iron core stator 5 is sleeved onto the support sleeve 11 from bottom to top, the positioning stop 112 contacts the top surface of the iron core stator 5 to position the iron core stator 5. After sleeved, the coil is placed onto the iron core stator 5. The power cord of 12 passes through the wire hole on the top plate 9 so that the power cord can be connected to the external power supply during operation (not shown in the figure); then the bottom plate 10 is welded to the bottom end of the support sleeve 11, and then the shielding sleeve 13 is fitted from bottom to top between the top plate 9 and the bottom plate 10. Then the two ends of the shielding sleeve 13 are welded to the top plate 9 and the bottom plate 10 respectively. At this time, the top plate 9, the bottom plate 10, the support sleeve 11 and the outer shielding sleeve 13 together form a completely closed glue-sealed space B. S2. Fill the sealing space B with adhesive, and then cure it after filling. S3. After curing, as follows Figure 6 As shown, the shaft 6 is assembled in the inner cavity of the support sleeve 11 by the bearing 16, so that one end of the shaft 6 extends out from the bottom end of the support sleeve 11; after the shaft 6 is assembled, an oil seal 17 is provided at one end near the shaft 6 and inside the bottom end of the support sleeve 11. The oil seal 17 is provided here mainly to prevent the fluid medium during the working process from entering the inner cavity of the support sleeve 11 and damaging the bearing. S4, such as Figure 7 As shown, the magnet rotor 8 and impeller 7 are first welded together, and then the impeller 7 is assembled onto one end of the shaft 6, so that the magnet rotor 8 is located on the outer periphery of the iron core stator 5, and a radial air gap H is left between it and the iron core stator 5 to form an external rotation radial flux motor structure. S5. Finally, as Figure 1 As shown, the outer casing 112 is fitted onto the outer periphery of the externally rotating radial flux motor structure, such that the outer casing 112 is positioned between the top plate 9 and the pump housing 111. Bolt 15 is passed through the top plate 9 and the pump housing 111 and then locked, thereby connecting the top plate 9, the outer casing 112 and the pump housing 111 together.

[0029] In step S2, the glue-filling process employs a combination of step-by-step glue-filling and alternating vacuuming. First, a portion of the volume of insulating glue 14 is poured into the sealed space B. Then, the sealed space B is vacuumed to remove any air bubbles. Next, another portion of insulating glue is poured in, and vacuuming is performed again. This alternating glue-filling and vacuuming process is repeated until the sealed space B is completely filled with insulating glue. Finally, curing is performed. A glue-filling hole and a vacuuming hole (not shown in the figure) are provided on the top plate 9 to allow for glue-filling and vacuuming operations within the sealed space B. In this embodiment, the top plate 9, bottom plate 10, support sleeve 11, and outer shielding sleeve 13 together form a completely enclosed sealed space B. The iron core stator 5 and coil 12 are both located within the sealed space B. Because the coil 12 wound on the iron core stator 5 has a very tight structure with numerous tiny gaps inside, if the insulating adhesive 14 is filled directly in one go, the high viscosity of the adhesive can easily trap air in the deep gaps of the coil 12, forming air bubbles that cannot be expelled. This embodiment uses a process combining step-by-step adhesive filling with alternating vacuuming. Under vacuum pressure, the air trapped inside the adhesive and in the bottom gaps rapidly expands and floats to the liquid surface, breaking and being effectively extracted, thus completely removing the air from the sealed space B. This fundamentally eliminates internal condensation caused by alternating temperature differences during operation. Simultaneously, the bubble-free solid insulator provides an excellent thermal bridge, allowing the heat generated by the coil to be conducted to the shielding sleeve without thermal resistance, greatly improving the efficiency of water cooling.

[0030] When assembling the shaft in step S3, as follows: Figure 5 and Figure 6 As shown, the bearing 16 is first assembled onto the shaft 6, and then the entire bearing 16 is inserted into the support sleeve 11 from its top port. After assembly, the top cover 18 is then tightened onto the top port of the support sleeve 11 with screws. A clamping sleeve 19 is also provided in the support sleeve 11, located between the top cover 18 and the bearing 16 near the top cover 18. A stepped bearing positioning stop 20 is also provided on the inner circumferential surface of the support sleeve 11. When the top cover 18 is tightened, the top cover 18 contacts the clamping sleeve 19, causing the clamping sleeve 19 to press against the outer ring of the bearing 16 near the top cover 18, and the outer ring of the bearing 16 near the bearing positioning stop 20 to contact the bearing positioning stop 20, thereby assembling the shaft 6 into the inner cavity of the support sleeve 11. This arrangement facilitates the assembly and disassembly of the shaft.

[0031] Example 2: Compared with Example 1, the difference lies in the assembly structure between the shaft and the impeller. For example... Figure 8As shown, in Embodiment 1, a rectangular protrusion 611 is provided on one end of the shaft 6. The diameter of the protrusion 611 is less than the diameter of the shaft 6, thus forming a shaft end step 612 between the protrusion 611 and the shaft 6. A groove 711 matching the shape of the protrusion 611 is provided at the center of the impeller 7. During assembly, the protrusion 611 of the shaft 6 is inserted into the groove 711 of the impeller 7, and then the assembly screw 21 is screwed into the end face of the protrusion 611 through the baffle 22. The baffle 22 is used to press the impeller 7 against the shaft end step 612 on one end of the shaft 6, thus assembling the shaft 6 and the impeller 7. However, in the actual assembly process, the applicant found that because the impeller 7 and the outer magnetic rotor 8 form an integrated shell structure, and the radial air gap H between the magnet 812 of the outer rotor structure and the iron core stator 5 is designed to be extremely small. When the operator manually inserts the impeller assembly axially, if the rectangular protrusion 611 at the shaft end and the positioning groove 711 of the impeller fail to achieve precise circumferential pre-alignment, the highly magnetic magnet 812 will cross the tiny air gap H and prematurely form a strong radial magnetic attraction with the iron core stator 5. This sudden and uncontrollable radial magnetic attraction will cause the impeller assembly to instantly deflect and jam on the stator, resulting in the center positioning protrusion completely losing its insertion and alignment space. At this point, the operator must overcome the enormous magnetic attraction to forcibly pull it out and separate it, and then try to align it again in the air. This results in the entire assembly process being too time-consuming and difficult to align, severely restricting production efficiency and assembly yield.

[0032] In this embodiment, as Figure 9As shown, the structure between the protruding end 611 and the groove 711 has been changed to a conical fit structure. That is, the protruding end 611 is set as an inverted conical frustum with a larger upper part and a smaller lower part, and the groove 711 is set as a conical groove that matches the shape of the protruding end 611. During assembly, the protruding end 611 of the shaft 6 is inserted into the groove 711 of the impeller 7, and then the assembly screw 21 is screwed into the end face of the protruding end 611 through the baffle 22. Thus, the baffle 22 is used to press the impeller 7 against the shaft end step 612 on one end of the shaft 6, thereby assembling the shaft 6 and the impeller 7 together. This embodiment adopts a "conical surface fit" structure, utilizing the progressive guidance and automatic centering principle of a conical surface. The lower end of the protruding end 611 has the smallest dimension, while the upper end of the groove 711 has the largest dimension. In the initial assembly stage, the operator only needs to roughly align the small end of the protruding end 611 with the wide opening of the groove 711 for easy insertion, greatly widening the tolerance range of the initial alignment. As the impeller 7 moves continuously, the protruding end 611 and the conical slope of the groove 711 begin to contact. Under the action of axial pressure, the conical slope will generate a radial component force. This component force can forcibly overcome the unilateral radial magnetic attraction force brought by the magnet 812, forcing the impeller 7 and the magnet rotor 8 to adjust evenly in the circumference during the pressing process, automatically and accurately retracting and aligning towards the central axis of the shaft 6. In this way, the problem of component misalignment and jamming caused by magnetic adsorption is completely solved, and the risk of scratching the anti-corrosion coating on the surface of the stator and rotor caused by repeated insertion and removal is avoided. Thanks to the self-centering function of the conical surface, operators no longer need to perform meticulous manual alignment in mid-air, achieving a "one-plug-and-accurate" foolproof blind assembly, significantly reducing assembly difficulty and greatly improving assembly efficiency on the production line. After final locking, the tight fit between the conical surfaces not only eliminates radial assembly gaps but also ensures extremely high concentricity between the impeller and the shaft system, further reducing eccentric vibration during equipment operation.

[0033] Example 3: Compared with Example 1, the difference is that in this example, the shaft is fixed, and one end of the shaft is rotatably connected to the impeller via a bearing. In Example 1, the shaft 6 rotates together with the impeller 7 and the magnetic rotor 8. In this example, the shaft is stationary, and only the impeller 7 and the magnetic rotor 8 rotate together. This completely eliminates the alternating stress and high-frequency vibration caused by slight eccentricity or fluid disturbance during high-speed rotation, fundamentally eliminating the potential mechanical fatigue of the main shaft and greatly extending its service life. In addition, by rotating the impeller directly onto the fixed shaft end via the bearing, the force support point of the rotating component (bearing) is moved directly to the inside or very close to the impeller (i.e., the fluid force-bearing body). This structure further reduces the outward offset of the impeller's center of gravity, and can more perfectly overcome the "cantilever effect" compared to Example 1. Furthermore, when the shaft is fixed, the dynamic oil seal (such as oil seal 17 in Example 1) that was originally required to prevent the fluid medium from entering the inner cavity of the support sleeve along the rotating shaft can be replaced with a static seal with a simpler structure and longer service life. This change completely eliminates the risk of fluid leakage caused by the aging and wear of dynamic seals due to long-term high-speed friction.

[0034] Example 4: Compared with Examples 1, 2, and 3, the difference is as follows: Figure 10 As shown, the central axes of inlet 3 and outlet 4 are parallel to each other. This arrangement allows the pump to be directly "connected in series" or "embedded" in the middle of a straight pipeline, greatly simplifying the complexity of pipeline laying and reducing construction costs.

[0035] In summary, this invention, through its unique spatial layout, effectively overcomes the spatial limitations of traditional centrifugal pumps and disc-type motor-driven pumps, achieving a significant reduction in overall size and weight. Simultaneously, the invention achieves complete decoupling and "unloading" of the main shaft function: this "unloading" design completely eliminates the potential mechanical fatigue risks caused by the main shaft simultaneously bearing torsional and bending stresses under complex fluid resistance. Through a reverse-wrapping nested design, the overall center of gravity of the rotating component (the combination of the magnet rotor and impeller) is significantly moved closer to the shaft's support center, greatly improving the coincidence between the center of gravity and the geometric center. This perfectly counteracts the eccentric torque generated under high-speed operation and fluid impact, resulting in smoother rotation and completely solving the problems of high-frequency wobbling and easy bearing wear caused by the "cantilever effect" of the main shaft in existing technologies. The use of a process combining step-by-step potting and alternating vacuuming allows the air trapped inside the insulating adhesive and in the bottom gaps to rapidly expand and float to the liquid surface under vacuum negative pressure, effectively removing it and completely eliminating air from the sealed space B. This fundamentally eliminates internal condensation caused by temperature fluctuations during operation. Simultaneously, the bubble-free solid insulator provides an excellent thermal bridge, allowing heat generated by the coil to be transferred to the shielding sleeve without thermal resistance, significantly improving water cooling efficiency. The "conical mating" structure utilizes the progressive guidance and self-centering principle of the conical surface for impeller and shaft assembly, completely resolving component misalignment and jamming issues caused by magnetic adsorption, and avoiding the risk of scratches to the anti-corrosion coating on the stator and rotor surfaces from repeated insertion and removal. Thanks to the self-centering function of the conical surface, operators no longer need to perform meticulous manual alignment, achieving "one-click" blind assembly, greatly reducing assembly difficulty and significantly improving assembly efficiency on the production line. After final tightening, the tight fit between the conical surfaces not only eliminates radial assembly gaps but also ensures a high degree of concentricity between the impeller and shaft system, further reducing eccentric vibration during equipment operation.

[0036] In the embodiments, "multiple" refers to "two or more". The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the protection scope of the invention, which is defined by the claims.

Claims

1. An externally rotating compact inline centrifugal pump, comprising: The pump body has a fluid cavity inside, and an inlet and an outlet communicating with the fluid cavity are provided on the pump body. The externally rotating compact pipeline centrifugal pump further includes: an iron core stator, fixedly installed in the pump body; a shaft, assembled at the center of the inner circle of the iron core stator, with one end of the shaft extending from the iron core stator; an impeller, disposed in the fluid cavity and connected to one end of the shaft; and a magnetic rotor, fixed to the impeller and rotating synchronously with the impeller. The magnetic rotor is located on the outer periphery of the iron core stator, with a radial air gap H between it and the iron core stator to form an externally rotating radial flux motor structure. The electromagnetic force generated by the externally rotating radial flux motor structure drives the impeller to rotate, and under the rotation of the impeller, the fluid medium is drawn in from the inlet and discharged from the outlet.

2. The external rotary compact pipeline centrifugal pump according to claim 1, characterized in that: The magnet rotor includes an annular sidewall and magnets disposed on the inner circumferential surface of the annular sidewall; the bottom end of the annular sidewall is fixed to the top surface of the impeller, so that the magnet rotor and the impeller form an integral shell-like structure with one side opening, and the shell-like structure is fitted and covers the outside of the iron core stator.

3. The external rotary compact pipeline centrifugal pump according to claim 2, characterized in that: A top plate and a bottom plate are provided inside the fluid cavity of the pump body. A support sleeve is provided between the top plate and the bottom plate. The inner circumferential surface of the iron core stator is fitted onto the outer circumferential surface of the support sleeve. The shaft is assembled in the inner cavity of the support sleeve, and one end of the shaft extends out from the support sleeve. A shielding sleeve is also provided between the top plate and the bottom plate and at the position of the outer circumferential surface of the support sleeve. The top plate, the bottom plate, the support sleeve, and the shielding sleeve together form a completely closed encapsulated space B. The iron core stator and the coil wound on it are located in the encapsulated space B, and the encapsulated space B is filled with insulating glue.

4. The external rotary compact pipeline centrifugal pump according to claim 3, characterized in that: The pump body includes a pump casing and a cylindrical outer casing. The bottom end of the outer casing contacts the top of the pump casing, and the top end of the outer casing contacts the top plate. The top plate, the outer casing, and the pump casing are connected together by bolts passing through the top plate and the pump casing.

5. The external rotary compact inline centrifugal pump according to any one of claims 1 to 4, characterized in that: The shaft is rotatably connected to the inner cavity of the support sleeve via a bearing, and the impeller is fixedly connected to one end of the shaft.

6. The external rotary compact inline centrifugal pump according to any one of claims 1 to 4, characterized in that: The shaft is fixed in the inner cavity of the support sleeve, and the impeller is rotatably connected to one end of the shaft through a bearing.

7. The external rotary compact pipeline centrifugal pump according to claim 5, characterized in that: One end of the shaft is provided with a protruding end, and the center of the impeller is provided with a groove that matches the shape of the protruding end; the protruding end is an inverted frustum-shaped cone that is larger at the top and smaller at the bottom, and the groove is a conical groove; during assembly, the protruding end is inserted into the groove and screwed into the end face of the protruding end by a mounting screw that passes through the baffle, and the baffle is used to press the impeller against the shaft end step on one end of the shaft, thereby fixing the impeller to one end of the shaft.

8. The external rotary compact pipeline centrifugal pump according to claim 7, characterized in that: The central axes of the inlet and outlet are perpendicular to each other or parallel to each other.

9. A method for manufacturing an externally rotating compact pipeline centrifugal pump according to claim 4, characterized in that, Includes the following steps: S1. First, fix the top of the support sleeve to the bottom surface of the top plate, then fit the iron core stator with the coil onto the outer circumference of the support sleeve; pass the power line of the coil on the iron core stator through the wire hole of the top plate; fix the bottom plate to the bottom end of the support sleeve, fit the shielding sleeve between the top plate and the bottom plate and fix both ends to form a completely closed glue seal space B. S2. Fill the sealing space B with adhesive, and then cure it after filling. S3. After curing, assemble the shaft in the inner cavity of the support sleeve so that one end of the shaft extends out from the bottom of the support sleeve. S4. First, fix the magnet rotor and impeller into one piece, and then assemble the impeller onto one end of the shaft, so that the magnet rotor is located on the outer periphery of the iron core stator and leaves a radial air gap H, so as to form an external rotation radial flux motor structure. S5. Fit the outer casing onto the outer periphery of the externally rotating radial flux motor structure, and connect the top plate, outer casing, and pump casing together using bolts.

10. The manufacturing method according to claim 9, characterized in that: The potting process in step S2 adopts a combination of step-by-step potting and alternating vacuuming. Specifically, a portion of the volume of insulating adhesive is first poured into the sealing space B, followed by vacuuming to remove internal air bubbles; then a portion of the volume of insulating adhesive is poured in again and vacuumed again; this process is repeated until the sealing space B is completely filled with insulating adhesive, and finally, curing is performed.

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