A motor for a high-speed pump

Abstract

The present invention discloses a motor for a high-speed pump. By setting the inside of the motor shaft as a hollow structure, through holes are radially formed at the joints of the motor shaft where the thrust ring, the first bearing and the second bearing are connected. An internal medium channel is formed between the shielding sleeve and the motor rotor assembly, and a cooling medium is pre-stored in the medium channel. The internal medium channel is connected to the hollow part of the motor shaft through the through holes. When the motor rotates, the cooling medium forms an internal cooling cycle in the motor, taking away the heat generated by bearing friction, the motor rotor and the motor stator. Epoxy resin is potted between the stator winding and the inner and outer casings, greatly improving the heat dissipation capacity of the winding. The present invention improves the service life of the bearing system, prevents the demagnetization of the magnetic steel, and can also significantly reduce the running noise and vibration of the motor. There is no leakage risk, no mechanical seal and no maintenance required, improving the motor efficiency and expanding the application range of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and particularly to a motor for a high-speed pump. Background Art

[0002] A canned motor has no mechanical seal, and the conveyed medium can directly pass between the stator and the rotor, which can lubricate and cool the bearing system and also take away the heat of the stator and rotor. In recent years, high-speed motors, especially permanent magnet synchronous motors, have developed rapidly. The motor speed can be increased to twice or even three times the traditional mains operating frequency of 2900 RPM (50 HZ) and 3500 RPM (60 HZ), reaching above 8000 - 10000 RPM. After the increase, the volume and weight of the motor and its load can be greatly reduced, and the power density and efficiency can be improved.

[0003] Traditional canned motors use graphite radial sliding bearings, which cannot withstand high-speed loads and have a short service life. Moreover, high rotational speed and high power density will bring higher heat dissipation requirements. The permanent magnet rotor magnets have poor heat resistance, and high temperatures will instantly demagnetize the magnets, resulting in a decline or even failure of the motor performance.

[0004] In view of this, it is urgent to improve the structure of the existing motor to improve the heat dissipation effect, ensure the service life of the bearing system, and enhance the motor efficiency. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing motor has poor heat dissipation effect during high-speed operation and is prone to demagnetization of the magnets.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is to provide a motor for a high-speed pump, which includes a motor shaft, a motor rotor assembly, and a motor stator assembly arranged inside a motor housing. The inside of the motor shaft is a hollow structure. The motor shaft is rotatably arranged inside the motor through a thrust ring, with a first bearing provided at the upper end and a second bearing provided at the lower end. The motor shaft is radially provided with through holes at the joints of the thrust ring, the first bearing, and the second bearing. The motor shaft drives the motor rotor assembly to rotate. A shielding sleeve is wrapped outside the motor rotor assembly, and an internal medium channel is formed between the shielding sleeve and the motor rotor assembly. Cooling medium is pre-stored in the medium channel. The internal medium channel is connected to the hollow part of the motor shaft through the through holes. The motor stator assembly is arranged around the motor rotor assembly.

[0007] In the above technical solution, the motor rotor assembly includes:

[0008] A rotor sheath, which is wrapped around the motor rotor, and both ends of the rotor sheath are pressed tightly on both sides by means of spinning and curling the edges;

[0009] The plastic cover plate is divided into an upper rotor cover plate and a lower rotor cover plate, which are respectively arranged at two ends of the motor rotor.

[0010] In the above technical solution, the motor stator assembly includes a stator core and a winding, and the winding is placed in a sealed cavity, and the sealed cavity is filled with epoxy resin.

[0011] In the above technical solution, the thrust ring is arranged between the rotor upper cover plate and the first bearing.

[0012] In the above technical solution, the thrust ring is formed by injection molding, has radial grooves distributed on the end, and has toothed grooves on the inner side for interference fit with the radial through hole of the motor shaft.

[0013] In the above technical solution, the upper end of the motor shaft passes through the thrust ring and is rotatably arranged in the upper flange, and the lower end passes through the lower flange.

[0014] In the above technical solution, an upper bearing seat is arranged below the upper flange and is fixedly connected by bolts, and a lower bearing seat is arranged below the lower flange and is fixedly connected by bolts.

[0015] In the above technical solution, a planar thrust bearing assembly is arranged between the rotor lower cover plate and the second bearing, and the thrust bearing assembly includes a thrust bearing seat that holds the shaft, a graphite planar thrust bearing moving ring, and a thin-walled sleeve on the outside of the thrust bearing seat, and a plurality of radial grooves are radially distributed on the upper end surface of the second bearing.

[0016] In the above technical solution, a wear-resistant coating is provided on the surface of the motor shaft.

[0017] In the above technical solution, an exhaust valve is provided on the upper flange, and the exhaust valve is used to balance the internal and external pressures of the motor and exhaust.

[0018] Compared with the prior art, a high-speed pump motor of the present invention sets the interior of the motor shaft as a hollow structure, and the motor shaft is provided with through holes in the radial direction where the thrust ring, the first bearing and the second bearing are connected. An internal medium channel is formed between the shielding sleeve and the motor rotor assembly, and a cooling medium is pre-stored in the medium channel. The internal medium channel is connected with the hollow part of the motor shaft through the through hole. When the motor rotates, the cooling medium forms a cooling cycle in the motor to take away the heat of the bearing friction and the motor rotor and the motor stator. The cavity formed by the stator winding and the inner and outer shells is filled with epoxy resin with high thermal conductivity, which greatly improves the heat dissipation capacity of the winding, thereby improving the life of the bearing system and preventing the demagnetization of the magnetic steel. At the same time, it can also significantly reduce the noise and vibration of the motor operation, without leakage risk, without mechanical seal and maintenance, thus improving the motor efficiency and expanding the application range of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Cross-sectional view of a motor for a high-speed pump in the present invention;

[0020] Figure 2 Cross-sectional view of the motor rotor assembly of a motor for a high-speed pump in the present invention;

[0021] Figure 3 Cross-sectional view of the thrust bearing assembly of a motor for a high-speed pump in the present invention;

[0022] Figure 4 Front view of the thrust bearing assembly of a motor for a high-speed pump in the present invention.

[0023] Wherein, Figures 1 to 4 The corresponding relationship between the reference numerals in the drawings and the component names is as follows:

[0024] 100 motor shaft, 200 motor rotor assembly, 300 motor stator assembly, 400 motor housing, 101 thrust ring, 102 first bearing, 103 second bearing, 104 shield, 105 internal medium channel, 106 upper flange, 107 lower flange, 108 exhaust valve, 201 upper rotor cover, 202 lower rotor cover, 203 rotor sheath, 204 rotor core, 205 permanent magnet, 301 stator core, 302 winding, 303 epoxy resin, 1021 radial groove, 109 thrust bearing assembly, 1091 thrust bearing seat, 1092 thrust bearing moving ring, 1093 thin-wall sheath. Specific embodiments

[0025] The present invention provides a motor for a high-speed pump, which can realize the internal cooling cycle of the motor, take away the heat of the bearing system, the motor stator and the motor rotor, and ensure the service life of the bearing system. The present invention will be described in detail below with reference to the accompanying drawings of the specification and specific embodiments.

[0026] Such as Figure 1 And Figure 2As shown in the figure, a motor for a high-speed pump provided by the present invention includes a motor shaft 100, a motor rotor assembly 200, and a motor stator assembly 300 disposed within a motor housing 400. The interior of the motor shaft 100 is a hollow structure. The motor shaft 100 is rotatably disposed within the motor through a thrust ring 101, with a first bearing 102 provided at the upper end and a second bearing 103 provided at the lower end. The motor shaft 100 is radially provided with through holes at the joints of the thrust ring 101, the first bearing 102, and the second bearing 103. The motor shaft 100 drives the motor rotor assembly 200 to rotate. An outer shielding sleeve 104 is provided around the motor rotor assembly 200, and an internal medium channel 105 is formed between the shielding sleeve 104 and the motor rotor assembly 200. Cooling medium is pre-stored in the medium channel. The internal medium channel 105 is connected to the hollow portion of the motor shaft 100 through the through holes. The motor stator assembly 300 is disposed around the motor rotor assembly 200, and the motor shaft 100 is connected to the pump shaft through a coupling.

[0027] In this embodiment, by setting the interior of the motor shaft 100 as a hollow structure, the motor shaft 100 is radially provided with through holes at the joints of the thrust ring 101, the first bearing 102, and the second bearing 103. An internal medium channel 105 is formed between the shielding sleeve 104 and the motor rotor assembly 200. Cooling medium is pre-stored in the medium channel. The internal medium channel 105 is connected to the hollow portion of the motor shaft 100 through the through holes. During the rotation of the motor, the cooling medium forms an internal cooling cycle within the motor, taking away the heat generated by bearing friction and the motor rotor and stator, improving the service life of the bearing system, preventing the demagnetization of the magnet 205, and at the same time significantly reducing the operating noise and vibration of the motor. There is no leakage risk, no mechanical seal and it is maintenance-free, improving the motor efficiency and expanding the application range of the motor.

[0028] Among them, the materials of the first bearing 102 and the second bearing 103 are hard materials such as silicon carbide zirconia. According to the characteristics of high speed and high load, the height of the mating section is reduced, and the inner diameter to height ratio is set between 0.4 and 0.8, preferably between 0.5 and 0.6.

[0029] In an embodiment of the present invention, preferably, the motor rotor assembly 200 includes:

[0030] A rotor sheath 203, which is wrapped around the entire motor rotor and is clamped on both sides at both ends by means of spinning and curling the edges.

[0031] Plastic covers, which are divided into a rotor upper cover 201 and a rotor lower cover 202, and are respectively disposed at both ends of the entire motor rotor.

[0032] In this embodiment, the rotor sleeve 203 is wrapped around the motor rotor assembly 200 as a whole, and the two ends of the rotor sleeve 203 are pressed on both sides by spinning and curling. The medium channel is between the rotor sleeve 203 and the shielding sleeve 104. The rotor sleeve 203 can effectively prevent the medium from entering the interior of the rotor, prevent the rotor core 204 and the magnetic steel 205 from oxidizing, and improve the service life of the motor and the user experience. The rotor sleeve 203 is a thin-walled shell, which can maintain tension for a long time after flanging, thereby ensuring axial and radial sealing pressure, improving the protection effect on the inside of the motor, and improving the service life of the motor. The plastic material has the advantage of light weight, which effectively reduces the overall weight of the rotor and reduces the moment of inertia. It is more suitable for the working conditions of high-speed motors, improves the safety and reliability of the motor, and does not require additional dynamic balancing, reduces installation steps, and improves user experience.

[0033] Among them, the plastic cover is one-piece injection molded, with a simple manufacturing method and high production efficiency. The cost is 1 / 10 of that of an ordinary metal cover, and four welding processes at both ends are eliminated, which greatly saves costs. The mass is only 1 / 8 of that of stainless steel at the same wall thickness, which reduces the overall mass of the rotor and the moment of inertia, making it more suitable for the working conditions of high-speed motors, and no additional dynamic balancing is required.

[0034] In one embodiment of the present invention, preferably, the motor stator assembly 300 includes a stator core 301 and a winding 302. The winding 302 is placed in a sealed cavity. The sealed cavity is filled with epoxy resin 303 with high thermal conductivity, which greatly improves the heat dissipation capacity of the winding.

[0035] In one embodiment of the present invention, preferably, the thrust ring 101 is disposed between the rotor upper cover plate 201 and the first bearing 102 .

[0036] In this embodiment, a thrust ring 101 is provided between the rotor upper cover plate 201 and the first bearing 102 , and is fixedly connected to the motor shaft 100 in the radial direction, and has a gap of 1 to 2 mm with the end surface of the first bearing 102 in the axial direction.

[0037] In one embodiment of the present invention, preferably, the thrust ring 101 is formed by injection molding, has radial grooves distributed on the end, and has toothed grooves on the inner side, which are interference fit with the radial through hole of the motor shaft 100 .

[0038] In this embodiment, a toothed groove is provided on the inner side of the thrust ring 101, which is in interference fit with the radial through-hole of the motor shaft 100, improving the tightness and reliability of the connection between the thrust ring 101 and the motor shaft 100. The cooling medium continuously forms a liquid film to provide axial support. The cooling medium can circulate inside and outside the hollow shaft to carry away the frictional heat. The thrust ring 101 is made of wear-resistant and high-temperature-resistant material, such as polytetrafluoroethylene (PTFE), which has better strength and toughness, provides an axial thrust effect during motor startup and shutdown, and will not be damaged even under light load during long-term continuous contact operation, and at the same time plays the role of a thrust bearing.

[0039] In an embodiment of the present invention, preferably, the upper end of the motor shaft 100 passes through the thrust ring 101 and is rotatably arranged in the upper flange 106, and the lower end passes through the lower flange 107.

[0040] In an embodiment of the present invention, preferably, an upper bearing seat is provided below the upper flange 106 and is fixedly connected by bolts, and a lower bearing seat is provided below the lower flange 107 and is fixedly connected by bolts.

[0041] In this embodiment, an upper bearing seat is provided below the upper flange 106 and is fixedly connected by bolts, and a lower bearing seat is provided below the lower flange 107 and is fixedly connected by bolts, effectively improving the stability and reliability of the fixation of the upper bearing seat and the lower bearing seat, and avoiding safety problems caused by the detachment of the upper bearing seat or the lower bearing seat.

[0042] As Figure 3 and Figure 4 shown, in an embodiment of the present invention, preferably, a flat thrust bearing assembly 109 is provided between the rotor lower cover plate 202 and the second bearing 103. The thrust bearing assembly 109 includes a thrust bearing seat 1091 that holds the shaft, a graphite flat thrust bearing dynamic ring 1092, and a thin-walled sheath 1093 outside the thrust bearing seat. A plurality of radial grooves 1031 are radially distributed on the upper end face of the second bearing 103.

[0043] In this embodiment, except that the thin-walled sheath is made of thin-walled metal material, other components are made of rubber and graphite. The overall mass is light and the moment of inertia is small, so that the radial dimension is greatly reduced compared with the traditional structure, and the circumferential linear velocity is significantly reduced at the same rotational speed, which can adapt to higher rotational speed working conditions.

[0044] In an embodiment of the present invention, preferably, an exhaust valve 108 is provided on the upper flange 106. The exhaust valve 108 is used to balance the pressure inside and outside the motor and exhaust gas.

[0045] In an embodiment of the present invention, preferably, a wear-resistant coating is provided on the surface of the motor shaft 100.

[0046] In this embodiment, the motor shaft 100 as a whole or the positions bearing friction are provided with wear-resistant coatings, or a bushing structure with a wear-resistant coating is provided. The coating processes include physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma thermal spraying, etc. Thermal spraying is preferred. The coating material is preferably tungsten carbide hard alloy, with a preferred hardness of HV1500 - 2200, and the coating thickness is 20 - 400 μm, preferably 120 - 150 μm, so that the motor shaft 100 has high hardness and wear-resistant characteristics, excellent bonding strength, peel resistance, heat resistance, impact resistance, is suitable for high-speed operating conditions, and has a long service life.

[0047] A motor for a high-speed pump provided by the present invention has a hollow structure inside the motor shaft. Radial through holes are provided at the joints of the motor shaft with the thrust ring, the first bearing, and the second bearing. An internal medium channel is formed between the shielding sleeve and the motor rotor assembly, and a cooling medium is pre-stored in the medium channel. The internal medium channel is connected to the hollow part of the motor shaft through the through holes. When the motor rotates, the cooling medium forms an internal cooling cycle in the motor, taking away the heat generated by bearing friction, the motor rotor, and the motor stator, improving the service life of the bearing system, preventing demagnetization of the magnetic steel, significantly reducing the operating noise and vibration of the motor at the same time, having no leakage risk, no mechanical seal and being maintenance-free, improving the motor efficiency, and expanding the application range of the motor.

[0048] In the present invention, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; the term "plural" means two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "joined", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "joined" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] The present invention is not limited to the above best implementation mode. Anyone should know that structural changes made under the inspiration of the present invention, as long as they have the same or similar technical solutions as the present invention, fall within the protection scope of the present invention.

Claims

1. A motor for a high-speed pump, comprising a motor shaft, a motor rotor assembly and a motor stator assembly disposed within a motor housing, characterized in that, The interior of the motor shaft is a hollow structure. The motor shaft is rotatably arranged inside the motor through a thrust ring, with a first bearing provided at the upper end and a second bearing provided at the lower end. The motor shaft is radially provided with through holes at the joints of the thrust ring, the first bearing and the second bearing. The motor shaft drives the motor rotor assembly to rotate. A shielding sleeve is wrapped around the outside of the motor rotor assembly, and an internal medium channel is formed between the shielding sleeve and the motor rotor assembly. A cooling medium is pre-stored in the medium channel. The internal medium channel is connected to the hollow part of the motor shaft through the through holes. The motor stator assembly is arranged around the motor rotor assembly; The motor rotor assembly includes: A rotor sheath, which is wrapped around the motor rotor and is clamped on both sides at both ends by means of spinning and curling the edges; Plastic covers, which are divided into an upper rotor cover and a lower rotor cover and are respectively arranged at both ends of the motor rotor; The motor stator assembly includes a stator core and windings. The windings are placed in a sealed cavity, and the sealed cavity is filled with epoxy resin; The thrust ring is arranged between the upper rotor cover and the first bearing; The thrust ring is formed by injection molding, with radial grooves distributed at the end, and tooth-shaped grooves on the inner side for interference fit with the radial through holes of the motor shaft.

2. The motor for a high-speed pump according to claim 1, characterized in that, The thrust ring is formed by injection molding, with radial grooves distributed at the end, and tooth-shaped grooves on the inner side for interference fit with the radial through holes of the motor shaft.

3. A motor for a high-speed pump according to claim 1, characterized in that, The upper end of the motor shaft passes through the thrust ring and is rotatably arranged in the upper flange, and the lower end passes through the lower flange.

4. The motor for a high-speed pump according to claim 3, characterized in that An upper bearing seat is arranged below the upper flange and is fixedly connected by bolts. A lower bearing seat is arranged below the lower flange and is fixedly connected by bolts.

5. A motor for a high-speed pump according to claim 1, characterized in that, A planar thrust bearing assembly is arranged between the lower rotor cover and the second bearing. The thrust bearing assembly includes a thrust bearing seat that holds the shaft, a graphite planar thrust bearing dynamic ring, and a thin-walled sheath outside the thrust bearing seat. Multiple radial grooves are radially distributed on the upper end face of the second bearing.

6. A motor for a high-speed pump according to claim 1, characterized in that, A wear-resistant coating is provided on the surface of the motor shaft.

7. The motor for a high-speed pump according to claim 3, characterized in that, An exhaust valve is provided on the upper flange, and the exhaust valve is used to balance the pressure inside and outside the motor and exhaust gas.

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