Motor for submersible well

Abstract

The present invention discloses a motor for a submersible well. The motor shaft is provided with a hollow structure inside. Through holes are provided in the radial direction of the thrust ring, the first bearing and the second bearing at the junction of the motor shaft. An internal medium channel is formed between the shield sleeve and the motor rotor assembly. Cooling water is pre-stored in the internal medium channel. The internal medium channel is connected to the hollow part of the motor shaft through the through hole. When the motor rotates, the cooling water forms a cooling cycle inside the motor to take away the heat of the bearing friction and the motor rotor and the motor stator. An outer cylinder is provided outside the motor to form an outer channel with the motor housing. The pumped medium is forced to cool the motor and take away the heat of the motor. The present invention effectively reduces the temperature rise of the motor, increases the service life of the bearing system, prevents the overheating and demagnetization of the magnetic steel and the insulation damage caused by the overheating of the winding, and can also significantly reduce the noise and vibration of the motor operation. There is no risk of leakage, no mechanical seal and maintenance-free, improves the efficiency of the motor, and expands the application range of the motor.

Description

Technical Field

[0001] The invention relates to the technical field of motors, and in particular to a motor for a submersible well. Background Art

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

[0003] Traditional shielded motors use graphite radial sliding bearings, which cannot withstand high speed loads and have a short lifespan. In addition, high speed and high power density will bring higher heat dissipation requirements. The permanent magnet rotor magnet has poor heat resistance, and high temperature will instantly demagnetize the magnet, causing motor performance degradation or even failure.

[0004] In view of this, there is an urgent need to improve the structure of existing motors to enhance heat dissipation, ensure the life of the bearing system, and improve 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 when running at high speed, which easily causes the problem of magnetic steel demagnetization.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is to provide a motor for a submersible well, including a motor shaft, a motor rotor assembly, a motor stator assembly, a motor housing and a motor casing. The interior of the motor shaft is a hollow structure. The motor shaft passes through a thrust ring and is rotatably arranged inside the motor. A first bearing is arranged at the upper end and a second bearing is arranged at the lower end. Through holes are opened in the radial direction where the thrust ring, the first bearing and the second bearing are connected. The motor shaft drives the motor rotor assembly to rotate. A shielding sleeve is wrapped around the outside of the motor rotor assembly, and a shielding sleeve is provided between the shielding sleeve and the motor rotor assembly. An internal medium channel is formed, and cooling water is pre-stored in the internal medium channel. The internal medium channel is connected to the hollow part of the motor shaft through a through hole. The motor stator assembly is arranged around the motor shaft. The motor is connected to the pump through a connecting device. The connecting device includes a first connecting part and a second connecting part arranged up and down. The first connecting part and the second connecting part are connected by a plurality of ribs. An annular groove is arranged on the upper part of the first connecting part. The annular groove is used to place a seal. The motor housing wraps the motor. The motor casing wraps the motor casing and forms an external medium channel with the motor casing.

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

[0008] The rotor sleeve is wrapped around the motor rotor as a whole, and the two ends of the rotor sleeve are pressed on both sides by spinning and curling;

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

[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 planar 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 motor for a submersible well 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, and an internal medium channel is formed between the shielding sleeve and the motor rotor assembly, and cooling water is pre-stored in the internal medium channel. The internal medium channel is connected with the hollow part of the motor shaft through the through hole, and the cooling water forms an internal cooling cycle of the motor when the motor rotates. When the motor drives the pump to pump water, the water flows from the pump through the connecting device into the external medium channel, thereby improving the service life of the bearing system and preventing the demagnetization of the magnetic steel. At the same time, it can also significantly reduce the running noise and vibration of the motor, without leakage risk, without mechanical seal and maintenance, thereby improving the efficiency of the motor and expanding the application range of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view of a motor for a submersible well in the present invention;

[0020] Figure 2 It is a cross-sectional view of a motor rotor assembly of a motor for a submersible well in the present invention;

[0021] Figure 3 A three-dimensional diagram of a connection device for a motor for a submersible well in the present invention;

[0022] Figure 4 It is a cross-sectional view of a thrust bearing assembly of a motor for a submersible well in the present invention;

[0023] Figure 5 It is a front view of a thrust bearing assembly of a motor for a submersible well in the present invention;

[0024] Figure 6 The present invention is a stereoscopic view of a thrust ring of a motor for a submersible well.

[0025] in, Figures 1 to 3 The corresponding relationship between the reference numerals and the component names is as follows:

[0026] 100 motor shaft, 200 motor rotor assembly, 300 motor stator assembly, 400 motor housing, 500 motor casing, 600 external medium channel, 700 connecting device, 101 thrust ring, 102 first bearing, 103 second bearing, 104 shielding sleeve, 105 internal medium channel, 106 upper flange, 107 lower flange, 108 exhaust valve, 201 rotor upper cover plate, 202 rotor lower cover plate, 203 sleeve, 204 rotor core, 205 magnetic steel, 301 stator core, 302 winding, 303 epoxy resin, 701 first connecting part, 702 second connecting part, 703 annular groove, 704 rib plate, 705 first annular boss, 706 second annular boss, 1031 radial groove, 109 thrust bearing assembly, 1091 thrust bearing seat, 1092 thrust bearing moving ring, 1093 thin-walled sleeve. DETAILED DESCRIPTION

[0027] The present invention provides a motor for a submersible well, which can realize dual cooling circulation inside and outside the motor shaft, take away the heat of the bearing system, the motor stator and the motor rotor, and ensure the life of the bearing system. The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments of the specification.

[0028] like Figures 1 to 3 As shown, a motor for a submersible well provided by the present invention comprises a motor shaft 100, a motor rotor assembly 200, a motor stator assembly 300, a motor housing 400 and a motor casing 500. The interior of the motor shaft 100 is a hollow structure. The motor shaft 100 passes through a thrust ring 101 and is rotatably arranged in the middle position of the motor. A first bearing 102 is arranged at the upper end, and a second bearing 103 is arranged at the lower end. The motor shaft 100 is provided with through holes in the radial direction where the thrust ring 101, the first bearing 102 and the second bearing 103 are connected. The motor shaft 100 drives the motor rotor assembly 200 to rotate. The motor rotor assembly 200 is wrapped with a shielding sleeve 104. An internal medium channel 105 is formed between the shielding sleeve 104 and the motor rotor assembly 200. A cold storage medium is pre-stored. The water is stored in the internal medium channel 105, and the internal medium channel 105 is connected to the hollow part of the motor shaft 100 through a through hole. The motor stator assembly 300 is arranged around the motor shaft 100, and the motor shaft 100 is connected to the pump shaft through a coupling. The motor and the pump are connected through a connecting device 700, and the connecting device 700 includes a first connecting part 701 and a second connecting part 702 arranged up and down, and the first connecting part 701 and the second connecting part 702 are connected by a plurality of ribs 704. An annular groove 703 is arranged on the upper part of the first connecting part 701, and the annular groove 703 is used to place a seal. The motor housing 400 is wrapped around the motor, and the motor casing 500 wraps the motor housing 400, and an external medium channel 600 is formed between the motor housing 400.

[0029] In this embodiment, the motor shaft 100 is provided with a hollow structure inside, through holes are opened in the radial direction of the thrust ring 101, the first bearing 102 and the second bearing 103 of the motor shaft 100, an internal medium channel 105 is formed between the shielding sleeve 104 and the motor rotor assembly 200, cooling water is pre-stored in the internal medium channel 105, and the internal medium channel 105 is connected with the hollow part of the motor shaft 100 through the through hole. When the motor rotates, the cooling water forms a cooling cycle inside the motor. When the motor drives the pump to pump water, the water flows from the pump through the connecting device 700 into the external medium channel 600, thereby realizing the heat dissipation mode of internal and external double circulation, accelerating the removal of the heat of the bearing friction and the motor rotor and the motor stator, prolonging the service life of the bearing system, preventing the demagnetization of the magnetic steel 205, and at the same time significantly reducing the noise and vibration of the motor operation, without leakage risk, without mechanical seal and maintenance-free, improving the motor efficiency, and expanding the application range of the motor.

[0030] Specifically, when the motor is working, the motor shaft 100 drives the motor rotor assembly 200 to rotate. The motor shaft 100 is hollow and a sealing plug is provided at the lower end. Therefore, during the rotation of the motor shaft 100, the cooling water in the internal medium channel 105 will enter the motor shaft 100 through the through hole on the motor shaft 100, and flow between the motor shaft 100 and the internal medium channel 105, thereby realizing internal circulation. When the motor drives the pump to pump water, the water flows through the connecting device 700 from the pump. The first connecting part 701 of the connecting device 700 is connected to the motor, and the second connecting part 702 is connected to the pump. The first connecting part 701 and the second connecting part 702 are connected by a rib plate 704, so that there is a gap between the first connecting part 701 and the second connecting part 702, and the water can enter the external medium channel 600 through the gap, thereby realizing external cooling.

[0031] Furthermore, an annular groove 703 is provided on the upper portion of the first connecting portion 701, and a seal can be placed in the annular groove to improve the sealing performance. The seal is an inner frame type, for example: GB / T13871.1-2007. During the cooling process, the cooling water in the internal circulation channel will be lost, thereby forming a pressure difference inside and outside the motor. When the pressure difference is greater than a preset value, the seal moves upward, so that the water pumped up by the pump enters the internal circulation channel as cooling water, thereby completing the replenishment of the cooling water in the internal circulation channel.

[0032] The water pumped by the water pump can effectively exchange heat with the internal cooling medium by flushing the wall of the external medium channel 600, taking away the heat of the internal medium, and further improving the heat dissipation capacity of the motor.

[0033] The first bearing 102 and the second bearing 103 are made of hard materials such as silicon carbide and zirconium oxide. According to the characteristics of high speed and high load, the height of the fitting section is reduced, and the inner diameter height ratio is set between 0.4 and 0.8, preferably 0.5 to 0.6.

[0034] like Figure 3 In one embodiment of the present invention, preferably, the first connection part 701 of the connection device 700 is used to connect with the motor, and the second connection part 702 is used to connect with the pump. A through hole is opened in the middle of the first connection part 701. The first connection part 701 is in the shape of an inverted frustum of a cone, and the second connection part 702 is cylindrical. The first connection part 701 is provided with a first annular boss 705 close to the through hole, and an annular groove 703 is provided on the upper part of the first connection part 701. The annular groove 703 is used to place a sealing ring. The first connection part 701 is connected to the first connection part and the second connection part 702 through a plurality of ribs 704, and a second annular boss 706 is provided around the upper part of the second connection part 702.

[0035] In this embodiment, the first connecting part 701 is used to connect with the motor and has an inverted frustum-shaped structure. The lower flange 107 of the motor abuts against the first connecting part 701, and the sleeve of the motor abuts against the upper surface of the second annular boss 706. The pump barrel wraps the pump setting, and the pump barrel abuts against the lower surface of the upper surface of the second annular boss 706. The motor shaft 100 passes through the through hole of the first connecting part 701 and is connected to the pump shaft through a coupling, which effectively avoids the wear caused by the mutual contact between the motor sleeve and the pump barrel. An annular groove 703 is provided on the upper part of the first connecting part 701. The annular groove 703 is used to place a sealing ring, which improves the sealing of the connection between the pump and the motor. The first connecting part 701 and the second connecting part 702 are connected by a rib plate 704. While ensuring that water can flow smoothly, the reliability and stability of the connection between the first connecting part 701 and the second connecting part 702 are effectively improved, thereby improving the user experience.

[0036] In one embodiment of the present invention, preferably, the motor rotor assembly 200 includes:

[0037] The rotor sleeve 203 is wrapped around the motor rotor as a whole, and both ends of the rotor sleeve 203 are pressed tightly by spinning and curling;

[0038] The plastic cover plate is divided into an upper rotor cover plate 201 and a lower rotor cover plate 202, which are respectively arranged at two ends of the motor rotor.

[0039] In this embodiment, the sleeve 203 is wrapped around the motor rotor assembly 200 as a whole, and the two ends of the sleeve 203 are pressed on both sides by spinning and curling. The medium channel is between the sleeve 203 and the shielding sleeve 104. The 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 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 mass 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.

[0040] 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 ordinary metal covers, and the four welding processes at both ends are omitted, 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.

[0041] 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.

[0042] 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 .

[0043] 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.

[0044] 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 .

[0045] In this embodiment, a toothed groove is provided on the inner side of the thrust ring 101, which is interference fit with the radial through hole of the motor shaft 100, thereby improving the tightness and reliability of the connection between the thrust ring 101 and the motor shaft 100. The cooling water continuously forms a liquid film to provide axial support. The cooling water can circulate inside and outside the hollow shaft to take away the friction heat. The thrust ring 101 is made of wear-resistant and high-temperature resistant materials, such as polytetrafluoroethylene FTFE, which has better strength and toughness, provides axial thrust effect when the motor is started and stopped, and will not be damaged even if it is in continuous contact for a long time under a lighter load, and at the same time plays the role of a thrust bearing.

[0046] In one embodiment of the present invention, preferably, the upper end of the motor shaft 100 passes through the thrust ring 101 and is rotatably disposed in the upper flange 106 , and the lower end passes through the lower flange 107 .

[0047] In one embodiment of the present invention, preferably, an upper bearing seat is provided below the upper flange 106 and fixedly connected by bolts, and a lower bearing seat is provided below the lower flange 107 and fixedly connected by bolts.

[0048] In this embodiment, an upper bearing seat is arranged below the upper flange 106 and is fixedly connected by bolts, and a lower bearing seat is arranged below the lower flange 107 and is fixedly connected by bolts, which effectively improves the stability and reliability of the fixation of the upper bearing seat and the lower bearing seat and avoids safety problems caused by the upper bearing seat or the lower bearing seat falling off.

[0049] In one embodiment of the present invention, preferably, a planar thrust bearing assembly 109 is arranged between the rotor lower cover plate 202 and the second bearing 103, and the thrust bearing assembly 109 includes a thrust bearing seat 1091 that holds the shaft, a graphite planar thrust bearing moving ring 1092, and a thin-walled sleeve 1093 on the outer side of the thrust bearing seat, and a plurality of radial grooves 1031 are radially distributed on the upper end surface of the second bearing.

[0050] In this embodiment, except for the thin-walled sheath which is made of thin-walled metal, other parts are made of rubber and graphite. The overall weight 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 speed, which can adapt to higher speed conditions.

[0051] Among them, the thrust bearing seat 1091 is made of oil-resistant rubber material, with light overall mass, small moment of inertia, and can be adaptively adjusted within a certain angle range under axial load. It is in close rotational contact with the end face of the second bearing 103. When rotating at high speed, the radial groove 1021 of the second bearing 103 can continuously generate an oil film, and the molecular tension on the surface of the oil film liquid can provide continuous thrust.

[0052] In one embodiment of the present invention, preferably, an exhaust valve 108 is provided on the upper flange 106, and the exhaust valve 108 is used to balance the internal and external pressures of the motor and exhaust.

[0053] In one embodiment of the present invention, preferably, the surface of the motor shaft 100 is provided with a wear-resistant coating.

[0054] In this embodiment, the motor shaft 100 as a whole or at a friction-bearing position is provided with a wear-resistant coating, or is provided with a sleeve structure with a wear-resistant coating, and the coating process includes physical vapor deposition PVD, chemical vapor deposition CVD, plasma thermal spraying, etc., preferably thermal spraying, and the coating material is preferably tungsten carbide cemented carbide, preferably with a hardness of HV1500-2200, a coating thickness of 20 to 400μ, preferably a thickness of 120-150μm, so that the motor shaft 100 has high hardness and wear resistance, excellent bonding strength, peeling resistance, heat resistance, impact resistance, adaptability to high speed conditions, and long service life.

[0055] The present invention provides a motor for a submersible well. The motor shaft is provided with a hollow structure inside. Through holes are opened in the radial direction of the motor shaft at the junction of 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. Cooling water is pre-stored in the internal 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 water forms a cooling cycle inside the motor. When the motor drives the pump to pump water, the water flows from the pump through the connecting device into the external medium channel, thereby realizing an internal and external double-circulation heat dissipation method, accelerating the removal of heat from bearing friction and the motor rotor and the motor stator, thereby increasing the service life of the bearing system and preventing the demagnetization of the magnetic steel. At the same time, the noise and vibration of the motor operation can be significantly reduced. There is no risk of leakage, no mechanical seal and maintenance-free, thus improving the motor efficiency and expanding the application range of the motor.

[0056] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" 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.

[0057] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone should be aware that any structural changes made under the inspiration of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention.

Claims

1. A motor for a submersible well, comprising a motor shaft, a motor rotor assembly, a motor stator assembly, a motor housing and a motor casing, characterized in that: The interior of the motor shaft is a hollow structure. The motor shaft passes through a thrust ring and is rotatably arranged inside the motor. A first bearing is arranged at the upper end, and a second bearing is arranged at the lower end. The motor shaft has through holes in the radial direction where the thrust ring, the first bearing and the second bearing are connected. The motor shaft drives the motor rotor assembly to rotate. A shielding sleeve is arranged outside the motor rotor assembly. An internal medium channel is formed between the shielding sleeve and the motor rotor assembly. Cooling water is pre-stored in the internal medium channel. The internal medium channel is connected to the hollow part of the motor shaft through a through hole. The motor stator assembly is arranged around the motor shaft. The motor is connected to the pump through a connecting device. The connecting device includes a first connecting part and a second connecting part arranged above and below. The first connecting part and the second connecting part are connected by a plurality of ribs. An annular groove is arranged on the upper part of the first connecting part. The annular groove is used to place a sealing member. The motor housing wraps the motor arrangement. The motor sleeve wraps the motor housing and forms an external medium channel with the motor housing. The motor rotor assembly comprises: A rotor sleeve is wrapped around the motor rotor, and both ends of the rotor sleeve are pressed tightly by spinning and curling; The plastic cover plate is divided into an upper rotor cover plate and a lower rotor cover plate, and is respectively arranged at both ends of the motor rotor as a whole; The motor stator assembly comprises a stator core and a winding, wherein the winding is placed in a sealed cavity filled with epoxy resin.

2. A submersible well motor according to claim 1, characterized in that: The thrust ring is arranged between the rotor upper cover plate and the first bearing.

3. A submersible well motor according to claim 1, characterized in that: The thrust ring is formed by injection molding, with radial grooves distributed on the end and toothed grooves on the inner side for interference fit with the radial through hole of the motor shaft.

4. A submersible well motor 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.

5. A submersible well motor according to claim 4, characterized in that: 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.

6. A submersible well motor according to claim 1, characterized in that: A thrust bearing assembly is arranged between the rotor lower cover plate and the second bearing. The thrust bearing assembly includes a thrust bearing seat that holds the shaft, a graphite plane thrust bearing dynamic ring, and a thin-walled sleeve on the outer side of the thrust bearing seat. A plurality of radial grooves are radially distributed on the upper end surface of the second bearing.

7. A submersible well motor according to claim 1, characterized in that: The surface of the motor shaft is provided with a wear-resistant coating.

8. A submersible well motor according to claim 4, characterized in that: 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 the gas.

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