Compact sealed variable frequency direct drive water pump

Abstract

The utility model discloses a compact sealed type variable frequency direct drive water pump passes integrated impeller section, sealing section, permanent magnet section and bearing section through integrated four stage reducing rotor shaft, sealing section axle diameter is accurate 0.5 0.8mm less than impeller section axle diameter, the impeller section installs impeller, and the impeller cooperation hydraulic sleeve connection realizes 99% torque transmission efficiency, sealing section link interface board - flange integrated forging spare, and the integrated silicon carbide ring is sealed with the inflation ring and constitutes axial double -channel sealing system, the permanent magnet section is equipped with 32 slot nickel plating matrix slot array, adopts the composite sheath structure from inside to outside, including equal length carbon fiber sheath and the metal isolating sleeve of two end extension 5 15mm, and the stator winding is covered through 3 0.3mm heat conduction epoxy resin pouring layer, and axial completely covers permanent magnet section and forms high -efficient heat dissipation channel. Ultimately realize axial size reduction 30%, and torque efficiency is greater than 99%, and the technical effect of zero leakage under high pressure working condition.

Description

Technical Field

[0001] This utility model relates to the field of water pump equipment manufacturing technology, and in particular to a compact, sealed variable frequency direct drive water pump. Background Technology

[0002] Current mainstream variable frequency water pumps are limited by their split-type structural design. The separate layout of the motor and pump body results in low axial space utilization, and parasitic losses in the coupling transmission link cause a 5%-8% loss in torque transmission efficiency. More seriously, due to the lack of shaft diameter differentiation design in the dynamic sealing area, the wear rate of the sealing surface reaches as high as 0.15mm / 1000h under high pressure conditions ≥1.6MPa, making it difficult to exceed the 8000-hour service life threshold. At the same time, the permanent magnet suffers from insufficient protection from the single-layer metal sheath in high-temperature environments above 80℃, with a magnetic flux attenuation rate of up to 12%; while the heat dissipation efficiency of the stator winding is generally lower than 0.8W / (m·K), and continuous temperature rise can easily trigger a demagnetization failure chain. The above-mentioned three major bottlenecks—structural redundancy, insufficient sealing reliability, and thermal management defects—severely restrict the improvement of energy efficiency and lifespan of high-pressure variable frequency water pumps. This utility model aims to solve this systemic problem through a compact sealed direct-drive architecture. Summary of the Invention

[0003] This application provides a compact, sealed variable frequency direct drive water pump. Through structural improvements such as an integrated four-stage variable diameter rotor shaft, double sealing components, and a permanent magnet multi-protection structure, it solves problems such as redundant axial dimensions, high-pressure seal failure, and permanent magnet demagnetization in traditional water pumps.

[0004] This application provides a compact, sealed variable frequency direct drive water pump, characterized in that it includes:

[0005] An integrated rotor shaft, wherein the integrated rotor shaft is arranged axially in the following order: impeller mounting section, sealing section, permanent magnet section and bearing section. The integrated rotor shaft adopts a four-stage variable diameter design. The impeller mounting section is equipped with an impeller. The permanent magnet section of the rotor shaft is provided with a permanent magnet slot array and is equipped with a permanent magnet array. The permanent magnet section is fitted with a carbon fiber sheath and a metal isolation sleeve from the inside to the outside.

[0006] The volute flow channel housing covers the impeller, and the end of the volute flow channel is provided with a 30° diameter contraction transition section;

[0007] The partition plate assembly includes a partition plate-flange component and a sealing component. The partition plate-flange component is integrally forged, and the sealing component is installed on the side of the partition plate-flange component that connects to the volute flow channel housing.

[0008] The stator mounting housing is fixedly installed to the volute flow channel housing with high-strength bolts via the dividing plate-flange component. The stator mounting housing is filled with stator windings, which form magnetic field coupling with the permanent magnet section. The end of the stator mounting housing is provided with a bearing chamber, which is installed and connected to the bearing section via an angular contact bearing.

[0009] Preferably, the permanent magnet segment is first covered with a carbon fiber sheath, and then the metal isolation sleeve is covered on the outside of the carbon fiber sheath. The length of the carbon fiber sheath is the same as the length of the permanent magnet segment, and the length of the metal isolation sleeve extends to both ends of the carbon fiber sheath.

[0010] Preferably, the stator winding core is fixed in the stator mounting housing by casting with thermally conductive epoxy resin, the casting layer thickness is 3±0.3mm, and the axial coverage completely envelops the permanent magnet section.

[0011] Preferably, the permanent magnet slot array has 32 slots evenly distributed circumferentially.

[0012] Preferably, the impeller and the impeller section are connected by a hydraulic sleeve, and the expansion amount is 0.06-0.10mm, preferably 0.08mm.

[0013] Technical effects:

[0014] This utility model integrates impeller / permanent magnet / bearing functional sections through a four-stage variable diameter shaft, and combines it with the integrated forging of the dividing plate and flange. The overall length of the machine is ≤70% of that of traditional models, achieving the technical effect of 30% axial compression of the variable frequency water pump.

[0015] The integrated conversion shaft diameter difference of this utility model creates a labyrinth effect, and the dividing plate integrates a silicon carbide ring and an intelligent inflatable sealing ring to dynamically compensate for wear, achieving a zero-leakage sealing effect.

[0016] This utility model's permanent magnet assembly combines a carbon fiber sheath with a 5-15mm extended metal isolation sleeve. The carbon fiber sheath has a centrifugal stress resistance of ≥800MPa, ultimately achieving a significant reduction in magnetic flux attenuation at high speeds. Furthermore, the stator assembly employs a 3±0.3mm thermally conductive epoxy resin casting layer to achieve efficient thermal management. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the compact sealed variable frequency direct drive water pump in Embodiment 1 of this application;

[0018] Figure 2 for Figure 1 An enlarged schematic diagram of part A in the middle;

[0019] Figure 3 for Figure 1 Enlarged schematic diagram of part B in the middle;

[0020] Figure 4 This is an enlarged schematic diagram of the integrated rotor shaft seal section.

[0021] 100 - Integrated rotor shaft; 110 - Impeller section; 120 - Sealing section; 130 - Permanent magnet section; 140 - Bearing section; 200 - Volute flow channel housing; 300 - Impeller assembly; 400 - Boundary plate assembly; 410 - Boundary plate-flange component; 420 - Sealing assembly; 421 - Silicon carbide ring; 422 - Gas-filled sealing ring; 500 - Stator area assembly; 510 - Stator mounting housing; 520 - Stator winding core; 530 - Thermally conductive epoxy resin; 600 - Permanent magnet assembly; 610 - Permanent magnet; 620 - Carbon fiber sheath; 630 - Metal isolation sleeve. Detailed Implementation

[0022] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods. Example

[0023] Please refer to Figures 1-4 A compact, sealed variable frequency direct drive water pump includes an integrated rotor shaft 100. The integrated rotor shaft is axially distributed as an impeller section 110, a sealing section 120, a permanent magnet section 130, and a bearing section 140. The integrated rotor shaft 100 adopts a four-stage variable diameter design. The shaft diameter of the sealing section 120 is 0.5-0.8 mm smaller than that of the impeller section 110. The shaft diameter of the permanent magnet section 130 is larger than that of the impeller section, and the shaft diameter of the bearing section 140 is smaller than that of the impeller section.

[0024] Impeller section 110 is equipped with impeller assembly 300. The impeller is connected by a hydraulic sleeve. The expansion range of the hydraulic sleeve connection is 0.06mm - 0.10mm, preferably 0.08mm, to achieve a torque transmission efficiency greater than 99%. When the expansion is 0.08±0.005mm, the torque transmission efficiency is ≥99.1%. For every ±0.01mm deviation in expansion, the efficiency decreases by 0.3%. The impeller section 110 is covered with a volute flow channel housing 200. The sealing section 120 is equipped with a dividing plate assembly 400. The dividing plate assembly includes a dividing plate-flange component 410 and a sealing component 420. The dividing plate-flange component 410 is integrally forged. The sealing component 420 is installed in the sealing section 120, and a groove is provided on the side of the dividing plate-flange component 410 that connects to the volute flow channel housing 200. The sealing assembly 420 includes a silicon carbide ring 421 and an inflatable sealing ring 422. The silicon carbide ring 421 is embedded in a concave groove of the dividing plate-flange component 410. The depth of the concave groove is greater than or equal to half the thickness of the silicon carbide ring 421. The inner diameter of the concave groove and the outer diameter of the silicon carbide ring form a transition fit to ensure that the silicon carbide ring 421 is axially fixed and has no radial movement. The inflatable sealing ring 422 is installed axially close to the exposed end face of the silicon carbide ring 421. Its centerline is 3-5 mm away from the stepped end face of the sealing section 120 shaft diameter, so that the labyrinth flow channel outlet is completely covered within the dynamic pressure compensation zone of the inflatable sealing ring, and the gap between the inner diameter of the inflatable sealing ring and the shaft surface is ≤0.05 mm. The 120mm shaft diameter of the sealing section is smaller than that of the 110mm shaft diameter of the impeller section. The reduction of the shaft diameter of the sealing section by 0.5-0.8mm forms a stepped labyrinth flow channel. The eddy current damping effect induced by the abrupt change in the flow channel cross section reduces the axial flow velocity of the medium by 47%. Together with the silicon carbide ring 421 and the inflatable sealing ring 422, a dynamic and static pressure mixed sealing interface is formed. The inflatable sealing ring 422 can generate a radial expansion force ≥120N under a gas pressure of 0.2MPa, which offsets the change in the sealing surface gap caused by the shaft diameter difference, ensures the stability of the dynamic and static pressure sealing interface, and makes the leakage rate <1×10-6mL / s@2.5MPa.

[0025] The permanent magnet segment 130 has 32 slots milled into the rotor base shaft, evenly distributed circumferentially, with a nickel-plated surface and epoxy resin filling. Permanent magnets 610 are embedded in each slot. The outer diameter of the permanent magnet segment after embedding the permanent magnets 610 remains the same. A carbon fiber sheath 620, with the same length as the permanent magnet segment 130, is fitted over the embedded permanent magnets 610. A metal isolation sleeve 630 is then fitted over the carbon fiber sheath 620, with an interference fit of 0.03-0.07 mm, preferably 0.05 mm. During assembly, the metal isolation sleeve 630 is shrunk by liquid nitrogen and then tightly fixed at room temperature. The axial length of the metal isolation sleeve 630 should extend at least 5-15 mm from each end of the permanent magnet segment 130 to form a reliable sealing area and protect the ends of the sheath. Optionally, a T800 grade carbon fiber wound sheath is used, with a centrifugal stress ≤1,650MPa at 10,000rpm and a safety factor ≥3.5. The carbon fiber sheath 620 controls the deformation rate of the permanent magnet 610 to <0.01%, and makes the air gap width fluctuation ≤5μm, thereby ensuring that the magnetic flux attenuation rate is ≤2.8%.

[0026] The dividing plate-flange component 410 is fixedly connected to the volute flow channel housing 200 and the stator mounting housing 510 by eight sets of circumferentially distributed M10 high-strength bolts, forming an axial sealing pressure boundary. The stator winding core 520 is fixed inside the stator mounting housing 510 by casting thermally conductive epoxy resin 530, with a casting layer thickness of 3±0.3mm. The thermally conductive epoxy resin 530 (thermal conductivity ≥1.2W / (m·K)) conducts heat from the stator winding to the stator mounting housing 510, ensuring thermal conductivity and mechanical properties. The axial coverage completely envelops the permanent magnet section of the stator winding, forming a magnetic field coupling with the permanent magnet section. After the casting body cures, the stator becomes a robust whole, improving its resistance to vibration and electromagnetic forces and reducing noise.

[0027] The stator mounting housing 510 has a bearing housing 540 at its end, which is connected to the bearing section 140 via paired angular contact bearings (back-to-back or face-to-face arrangement) and is preloaded. The bearing housing 540 is equipped with a forced circulation oil cooling system. When the oil cooling system flow rate is 5±0.5L / min, the oil film thickness is stable at 8-10μm, forming an elastic damping effect with the back-to-back paired angular contact bearings (preload 0.03-0.05mm), thus forming a high-speed support unit. This unit, in conjunction with a bidirectional non-contact labyrinth seal or a contact rotary shaft lip seal, prevents grease leakage and external media intrusion.

[0028] Additionally, for high-power models, relying solely on thermally conductive epoxy resin and natural heat dissipation from the housing may be insufficient. Options include adding heat dissipation fins to the outer surface of the stator mounting housing or equipping the stator mounting housing with a circulating cooling water jacket.

[0029] In addition, the pump is integrated with or equipped with a dedicated frequency converter, which has soft start, speed regulation, power monitoring and protection functions.

[0030] In addition, the inflatable sealing ring 422 can be connected to an external 0.2MPa regulated air source through an air passage embedded in the rotor shaft. Specifically, an axial air passage is opened in the rotor shaft sealing section 120, and a rotary pneumatic coupler is installed between the passage outlet and the inflatable sealing ring 422.

[0031] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0032] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A compact, sealed variable frequency direct-drive water pump, characterized in that, include: An integrated rotor shaft, wherein the integrated rotor shaft is arranged axially in the following order: impeller mounting section, sealing section, permanent magnet section and bearing section. The integrated rotor shaft adopts a four-stage variable diameter design. The impeller mounting section is equipped with an impeller. The permanent magnet section of the rotor shaft is provided with a permanent magnet slot array and is equipped with a permanent magnet array. The permanent magnet section is fitted with a carbon fiber sheath and a metal isolation sleeve from the inside to the outside. The volute flow channel housing covers the impeller, and the end of the volute flow channel is provided with a 30° diameter contraction transition section; The partition plate assembly includes a partition plate-flange component and a sealing component. The partition plate-flange component is integrally forged, and the sealing component is installed on the side of the partition plate-flange component that connects to the volute flow channel housing. The stator mounting housing is fixedly installed to the volute flow channel housing with high-strength bolts via the dividing plate-flange component. The stator mounting housing is filled with stator windings, which form magnetic field coupling with the permanent magnet section. The end of the stator mounting housing is provided with a bearing chamber, which is installed and connected to the bearing section via an angular contact bearing.

2. The compact, sealed, variable frequency direct-drive water pump according to claim 1, characterized in that, The permanent magnet segment is first covered with a carbon fiber sheath, and then the metal isolation sleeve is covered on the outside of the carbon fiber sheath. The length of the carbon fiber sheath is the same as the length of the permanent magnet segment, and the length of the metal isolation sleeve extends to both ends of the carbon fiber sheath.

3. The compact, sealed, variable frequency direct-drive water pump according to claim 1, characterized in that, The stator winding core is fixed inside the stator mounting housing by casting with thermally conductive epoxy resin. The casting layer is 3±0.3mm thick and completely encloses the permanent magnet section in the axial direction.

4. The compact, sealed variable frequency direct drive water pump according to claim 1, characterized in that, The permanent magnet slot array has 32 slots evenly distributed around the circumference.

5. The compact, sealed, variable frequency direct-drive water pump according to claim 1, characterized in that, The impeller and the impeller section are connected by a hydraulic sleeve, with an expansion amount of 0.08 mm.

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