High-efficiency and high-reliability motor rotor structure for shield pump
By designing that both ends of the rotor core are longer than the stator core, and adopting a penetrating reverse welding structure and Ω groove design, the magnetic leakage and heating problems caused by the large axial bleed of the rotor of the high-power shielded pump motor are solved, and a high-efficiency and high-reliability motor rotor structure is achieved.
Patent Information
- Application Number
- CN202421722314.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2034-07-19
Smart Images
Figure CN223039723U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electric pumps, and particularly relates to a high-efficiency and high-reliability motor rotor structure for a canned motor pump. Background Art
[0002] The canned motor pump features an integrated structure of the pump and the motor. The medium inside the pump needs to flow through the motor cavity. Therefore, the canned motor pump adopts a sliding bearing, a shaft sleeve and a thrust disc structure that requires medium lubrication. The advantage of the sliding bearing is that it can be lubricated by the medium, and the bearing does not require an independent sealing cavity and lubricant. The disadvantage is that the axial displacement of the bearing is relatively large. For canned motor pumps with a power of more than 250kW, the axial displacement is about 6 - 8mm. Excessive axial displacement will cause the stator and rotor cores of the motor not to align, reduce the effective core length, increase the magnetic leakage of the motor, reduce the efficiency, and cause serious heating.
[0003] Since the rotor of a high-power motor is long and large in volume, it cannot be made into a cast aluminum or cast copper rotor due to manufacturing process limitations. Therefore, a copper bar rotor is selected. When the copper bars and end rings of a conventional copper bar rotor are welded together, a certain operating space is required. Therefore, within a certain distance between the rotor core and the end ring of the copper bar rotor, there are only conducting bars and gaps. The shielding sleeve needs to cover the outer circle of the rotor as a whole to protect the copper bar rotor. However, the shielding sleeve and the gap cannot withstand the pressure of the medium inside the pump. A stainless steel protective sleeve needs to be added inside the shielding sleeve at the corresponding position to support and protect the shielding sleeve from damage. In this case, if the sliding bearing undergoes axial displacement and causes the stator and rotor cores of the motor not to align, the rotor sheath at the end of the rotor core will move into the corresponding area of the stator core. The stator magnetic field in the corresponding area of the stator core is very strong. The rotor stainless steel protective sleeve belongs to a large conductor, and the eddy current effect is obvious when the large conductor is in the magnetic field. The rotor sheath generates serious heat, and the overheating of the sheath may cause the rotor shielding sleeve to deform or even burn out, resulting in the abnormal operation of the motor. Even if there is no axial displacement, the rotor stainless steel protective sleeve will also be affected by the leakage magnetic field at the end of the stator core, with an obvious eddy current effect, serious heat generation of the rotor sheath, and reduction of the service life of the rotor.
[0004] In addition, the rotor shielding sleeve of a conventional canned motor pump is welded to the rotor end plate. When affected by the medium pressure and external impact, the rotor shielding sleeve is prone to deformation under force, resulting in easy cracking at the welded joint of the shielding sleeve.
[0005] Therefore, it is necessary to design a high-efficiency and high-reliability motor rotor structure for a canned motor pump. Summary of the Utility Model
[0006] The purpose of the utility model is to overcome the above-mentioned problems and provide a high-efficiency and high-reliability motor rotor structure for a canned motor pump.
[0007] The technical solution adopted by the utility model to achieve the above purpose is:
[0008] An efficient and highly reliable motor rotor structure for a canned motor, including a rotor core, on which a stator core is sleeved. Both ends of the rotor core extend beyond the length L of the stator core. The length of the stator core is A, and the length of the rotor core is B, where B = A + 2L.
[0009] The length L is 6 mm - 10 mm.
[0010] The rotor core includes a number of rotor punching sheets, which are pressed tightly by rotor pressing plates at both ends. An end ring and a rotor end plate are sequentially pressed on the rotor pressing plates, and copper bars are inserted between the rotor pressing plate and the end ring.
[0011] The copper bars and the end ring are welded at the end face of the rotor end plate by silver-copper solder.
[0012] An Ω groove is provided on the outer circle of the rotor end plate.
[0013] The features of the present utility model are: it has high efficiency and high reliability. Both ends of the rotor core are longer than the stator core, which can compensate for the corresponding displacement, ensure that the effective length of the motor remains unchanged, and thus ensure that the electromagnetic performance of the motor is not affected by the axial displacement generated by the sliding bearing; the end conductor bars of the rotor core adopt a penetrating reverse welding structure, which can withstand the pressure from the motor air gap, does not require a stainless steel sleeve for protection, avoids the eddy current loss caused by the stainless steel protective sleeve, reduces the motor heating, and improves the motor efficiency; by machining an Ω groove on the outer circle of the rotor end plate, the stress generated by the deformation of the shielding sleeve of the core part can be released, preventing cracking at the welding joint. Description of the Drawings
[0014] Figure 1 is the structural schematic diagram of the present utility model.
[0015] Figure 2 is Figure 1 the partial enlarged view M of
[0016] Figure 3 is Figure 1 the partial enlarged view N of
[0017] Wherein: 1. Stator core 2. Rotor core 21. Rotor punching sheet 22. Rotor pressing plate 23. End ring 24. Rotor end plate 241. Ω groove 25. Copper bar 26. Silver-copper solder 27. Rotor shielding sleeve. Detailed Embodiment
[0018] Such as Figures 1-3As shown in the figure, the utility model relates to a high-efficiency and high-reliability motor rotor structure for a canned motor pump, including a rotor core 2. A stator core 1 is sleeved on the rotor core 2. Both ends of the rotor core 2 extend beyond the length L of the stator core 1. The length L is 6 mm - 10 mm. The length of the stator core 1 is A, and the length of the rotor core 2 is B, where B = A + 2L.
[0019] For a conventional canned motor pump, A = B. However, the sliding bearing has a certain axial displacement. After the pump operates, the sliding bearings at both ends of the rotor will have axial displacement, and the rotor will move axially along with the bearings, resulting in misalignment of the stator and rotor cores. The effective length of the motor core becomes shorter, the axial magnetic leakage at the motor end increases, the axial magnetic pull generated by the motor becomes larger, the bearing load increases, the motor efficiency decreases, and the motor temperature rise becomes higher. For the canned motor pump of the utility model, B = A + 2L, and both ends of the rotor core 2 extend beyond the stator core by L (L = 6 mm - 10 mm). The specific value of L is given according to the axial displacement value of the sliding bearing. When the sliding bearing has displacement and causes a certain displacement of the motor rotor, the L length of the rotor core 2 can compensate for the corresponding displacement, ensuring that the effective length of the motor remains unchanged, and thus ensuring that the electromagnetic performance of the motor is not affected by the axial displacement generated by the sliding bearing.
[0020] The rotor core 2 includes a plurality of rotor punching sheets 21. The rotor punching sheets 21 are pressed tightly by rotor pressing plates 22 at both ends. An end ring 23 and a rotor end plate 24 are sequentially pressed on the rotor pressing plates 22. A copper bar 25 is inserted between the rotor pressing plate 22 and the end ring 23. The copper bar 25 and the end ring 23 are welded at the end face of the rotor end plate 24 by a silver-copper solder 26.
[0021] The end bar of the rotor core 2 of the utility model adopts a penetrating reverse welding structure. After the rotor punching sheets 21 and the rotor pressing plates 22 are stacked and pressed tightly with a tooling shaft to form the rotor core 2, the copper bar 25 is inserted into the rotor core 2, and then the copper bar 25 and the end ring 23 are welded full and flat with the silver-copper solder 26. Then, the outer end faces on both sides of the end ring 23 are processed flat. In this way, the copper bar rotor end structure is the same as the cast-aluminum rotor end structure, and there is no gap left between the end ring 23 and the rotor core 2, that is, a solid end ring, which can withstand the pressure from the motor air gap. The rotor shield 27 can be directly sleeved on the outside of the end ring 23 without the protection of a stainless steel sleeve, avoiding the eddy current loss caused by the stainless steel protective sleeve, reducing the motor heating, and improving the motor efficiency.
[0022] An Ω groove 241 is provided on the outer circle of the rotor end plate 24. Since the rotor of the canned motor needs to be isolated from the medium, that is, the rotor end plate 24 and the rotor shield 27 are used to protect the motor rotor by welding. However, the rotor shield 27 is easily deformed by external forces such as the medium pressure. The deformation at the welding joint of the rotor end plate 24 and the rotor shield 27 will generate stress, resulting in cracking at the welding position. Therefore, by machining an Ω groove 241 on the outer circle of the rotor end plate 24, the stress generated by the deformation of the shield of the iron core part can be released, preventing cracking at the welding joint.
[0023] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.
Claims
1. A high-efficiency and high-reliability motor rotor structure for a canned motor pump, comprising a rotor core, characterized in that: The stator core is mounted on the rotor core, and both ends of the rotor core are longer than the stator core by a length L. The stator core length is A, and the rotor core length is B, where B=A+2L. The rotor core includes a plurality of rotor punchings, which are pressed by rotor pressure plates at both ends. End rings and rotor end plates are pressed on the rotor pressure plates in sequence, and copper bars are inserted between the rotor pressure plates and the end rings.
2. A high-efficiency and high-reliability motor rotor structure for a canned motor pump as claimed in claim 1, characterized in that: The length of L is 4mm-10mm.
3. A high-efficiency and high-reliability motor rotor structure for a canned motor pump as claimed in claim 1, characterized in that: The copper strip and the end ring are welded to the end surface of the rotor end plate by silver-copper solder.
4. A high-efficiency and high-reliability motor rotor structure for a canned motor pump as claimed in claim 1, characterized in that: An Ω groove is formed on the outer circle of the rotor end plate.