Self-circulation double-shielding submersible motor for axial flow pump

Abstract

The invention belongs to the technical field of submersible motors, and particularly relates to a self-circulation double-shielding submersible motor for an axial flow pump, which comprises a rear end cover, a shell, a stator, a rotor, a front end cover, a sand throwing ring, a shaft, a graphite bearing and a shielding sleeve, the two graphite bearings are respectively arranged on the inner sides of the rear end cover and the front end cover; the stator is mounted in the shell; the rotor is installed on the shaft and limited in the axial direction and the radial direction through the bearing. The rear end cover and the front end cover are installed at the two ends of the shell respectively. The shielding sleeve is installed between the stator and the rotor and used for isolating the installation space where the stator is located. The sand throwing ring is mounted on the shaft; the inner circle of the graphite bearing is in clearance fit with the outer circle of the shaft; the outer circle of the shaft tail end is in clearance fit with the inner circle of the rear end cover; the rotor and the shaft rotate at a high speed under the gap, the shaft of the motor drives the impeller of the axial flow pump to rotate at a high speed, water is discharged in an axial flow mode, and self-circulation is formed. Through the design of the self-circulation flow channel, the overall heat dissipation performance is remarkably improved, and the structural complexity and design difficulty of the motor are greatly reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of submersible motors, and particularly relates to a self-circulation double-shield submersible motor for an axial flow pump. BACKGROUND

[0002] The submersible motor for an axial flow pump drives the pump impeller to rotate by a motor shaft, and water is discharged in an axial flow manner. The existing submersible motor for an axial flow pump is usually sealed in an oil-filled manner, and a mechanical seal is used at the shaft extension end. The structure is complex, and the insulating oil needs to be replaced regularly. The mechanical seal is implemented in the form of a dynamic seal structure, has poor reliability, and is prone to leakage, causing motor failure. The submersible motor is filled with water inside, the stator of the motor is in a shield sleeve, and the rotor cavity allows water to enter. The disadvantage is that the shield sleeve causes eddy current loss, and the efficiency is low. If the shield sleeve is damaged and leaks, the motor will fail. The axial flow pump impeller cannot form a pressure difference in the motor cavity, and water cannot form a circulation in the motor.

[0003] In the existing disclosed technology, patent CN222084736U discloses a liquid-cooled energy storage special cooling water pump. In the patent, the motor has a shield sleeve, and water circulation is achieved through a circulating pipe channel. It is only suitable for a centrifugal pump structure with a high-low pressure difference, and cannot meet the axial flow pump structure in which the liquid is transported along the pump shaft. For example, patent CN218472910U discloses a static seal structure of a submersible axial flow pump motor, which is a static seal structure of a motor end cover and a shell. In these disclosed structures, the core design idea is still to consider the sealing performance of the motor. However, for the design of the submersible motor for an axial flow pump, the heat dissipation performance of the motor needs to be considered in addition to the internal sealing performance. The internal design is in the form of a sealed structure, and relies on a cooling medium to achieve heat dissipation. The overall structure design has high difficulty, complexity and cost. SUMMARY

[0004] To solve the above problems, the application provides a double-shield self-circulation motor to improve the sealing performance of the submersible motor and solve the problems of circulation and heat dissipation in the motor cavity of the axial flow pump motor.

[0005] The technical scheme of the application is as follows: To achieve the above-mentioned purpose, the application provides a self-circulation double-shield submersible motor for an axial flow pump, which comprises a rear end cover, a shell, a stator, a rotor, a front end cover, a sand throwing ring, a shaft, graphite bearings, and a shield sleeve. The two graphite bearings are arranged on the inner sides of the rear end cover and the front end cover respectively. The stator is installed in the interior of the shell. The rotor is installed on the shaft and is limited in the axial and radial directions by the bearings. The rear end cover and the front end cover are installed at the two ends of the shell respectively. The shield sleeve is installed between the stator and the rotor to isolate the installation space of the stator. The sand throwing ring is installed on the shaft. The graphite bearing inner circle and the shaft outer circle, and the shaft tail end outer circle and the rear end cover inner circle are gap fit; after the submersible motor is powered on, the rotor and the shaft rotate at high speed under the gap, the shaft of the motor drives the axial flow pump impeller to rotate at high speed, and water is discharged in the form of axial flow to form self-circulation.

[0006] Further, the shaft tail end is provided with a spiral flow channel in the rear end cover inner portion; when the motor works normally, it is completely immersed in water, the high pressure is generated between the spiral structure outer circle of the shaft and the rear end cover inner circle in the gap therebetween, and the water is driven to flow along the axial direction through the rotating flow channel.

[0007] Further, the sand throwing ring is provided in the form of a brim and is installed at the shaft extension end; when the motor does not work, the sand throwing ring can block the impurities in the water from entering the motor through the gap between the shaft extension end and the front end cover; when the motor works, the shaft drives the sand throwing ring to rotate at high speed, and the impurities in the water can be thrown away from the motor.

[0008] Further, the graphite bearing end face is provided with a plurality of lubricating grooves, and the inner circle is further provided with spiral lubricating grooves communicated with the end face lubricating grooves.

[0009] Further, a filter screen is further installed on the rear end cover for filtering external impurities.

[0010] Further, the front and rear end covers are provided with a plurality of sealing ring grooves, and the static sealing is performed between the housing and the stator shielding sleeve through O-rings, so that the stator is completely isolated from water.

[0011] Further, the stator is filled with epoxy resin.

[0012] Further, the length-diameter ratio of the motor shaft is not less than 2. The technical effects of the present application are as follows: the self-circulation double-shielding submersible motor designed according to the present application is provided with a stator which is integrally filled with epoxy resin and is double-isolated by a shielding sleeve, so that the motor leakage problem is solved. The self-circulation flow channel is designed at the motor shaft end, the heat dissipation condition of the motor is improved, the impurities in the motor are cleaned, and the rotor is prevented from being stuck.

[0013] The application takes full advantage of the working characteristics of the submersible motor, and designs the stator part in the motor as an independent sealing structure, which only needs to adopt a static sealing structure design to complete the sealing of the stator installation space, greatly reducing the sealing design difficulty; specifically, the motor rotor and the motor shaft are designed without considering the sealing design problem, on the contrary, the application takes full advantage of the good heat absorption and dissipation characteristics of water in the working scene, installs an axial flow pump impeller on the motor output shaft, the axial flow pump impeller rotates at high speed, discharges water out of the motor in the form of axial flow, forms a self-circulation, and brings out the heat in the motor during the self-circulation process, achieving good heat dissipation characteristics. The design of the motor shaft solves the problem of easy leakage of dynamic sealing on one hand, and on the other hand, makes full use of the water in the working environment, significantly improves the overall heat dissipation performance through the self-circulation flow channel design, greatly reduces the complexity and design difficulty of the motor structure. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of a self-circulation double-shielded submersible motor for an axial flow pump.

[0015] Wherein, the rear end cover 1, the end cover O-ring 2, the epoxy resin 3, the shell 4, the stator 5, the rotor 6, the front end cover 7, the sand throwing ring 8, the shaft 9, the retainer 10, the graphite bearing 11, the stator O-ring 12, the shield sleeve 13, the screw 14, and the filter screen 15.

[0016] Figure 2 is a schematic diagram of the graphite bearing structure of the application; Figure 3 is a schematic diagram of the spiral flow channel design at the tail end of the shaft; Figure 4 is a schematic diagram of the sand throwing ring structure; Figure 5 is a schematic diagram of the water flow self-circulation during the working process of the motor of the application. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0018] The features and exemplary embodiments of the various aspects of the present application will be described in detail below with reference to the drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one of ordinary skill in the art that the present application can be practiced without some or all of these specific details. The description of the embodiments is merely illustrative of the present application and does not limit the scope of the present application. The present application is not limited to the specific settings and methods described below, but covers any modifications, equivalents, and alternatives falling within the spirit of the present application. In the drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessary obscuring of the present application.

[0019] It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict, and each embodiment can be referred to and cited by each other. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0020] The present application is to solve the problems of low reliability of dynamic sealing of the existing axial flow pump submersible motor, no circulation channel in the motor, poor heat dissipation of the motor, and rotor jam caused by impurities in the motor for a long time, and provides a self-circulation double-shielded submersible motor. The motor stator is integrally sealed and shielded to solve the motor leakage problem. The motor shaft end is designed with a self-circulation flow channel to improve the motor heat dissipation condition, clean the impurities in the motor, and prevent the rotor from jamming.

[0021] In the specific implementation process, the designed submersible motor mainly has a stator, a rotor, a graphite bearing, a shell, front and rear end covers, a filter screen, and a sand throwing ring. The stator is installed in the shell with interference, and the graphite bearing is installed in the end cover with interference. The rotor is installed on the shaft with interference. The working gap between the stator and the rotor is 0.3 mm. The friction gap between the shaft and the graphite bearing is 0.05 mm. The motor shaft drives the axial flow pump impeller to rotate, and the water is discharged in the form of axial flow.

[0022] Impurities will enter the motor cavity when the submersible motor works in different water areas. Long-term accumulation of impurities will block the motor working gap and the friction gap, causing the motor to jam. A spiral structure is designed at the rear end of the motor shaft. When the motor shaft rotates, the spiral shaft drives water to generate high pressure at the end of the motor shaft, so that the water enters from the rear end cover of the motor and flows out from the front end cover of the motor, carrying away the impurities inside the motor and keeping the inside of the motor clean.

[0023] The submersible motor uses graphite sliding bearing as bearing support rotation, and water for lubrication. The bearing end face is designed with 5 lubrication grooves, and the bearing inner cavity is designed as a spiral structure lubrication groove. The graphite bearing lubrication area is increased, and the efficiency of the submersible motor is improved.

[0024] The sand throwing ring is arranged at the shaft extension end of the submersible motor, and the sand throwing ring can block the impurities in water from entering the motor through the gap between the shaft and the end cover when the motor is not working. When the motor works, the shaft drives the sand throwing ring to rotate at high speed, so that the impurities at the shaft extension end are thrown out, the shaft extension end of the motor is kept clean, and the foreign matters are prevented from being stuck.

[0025] The filter screen is arranged on the rear end cover of the submersible motor, and the impurities entering the motor can be filtered to below 0.2mm*0.14mm. The gap between the stator and the rotor is 0.3mm, and the graphite bearing lubricating groove is 2mm, so that the impurities entering the motor through the filter screen cannot be stuck.

[0026] The stator of the submersible motor is integrally filled with epoxy resin, the stator is isolated from water, and the submersible motor can work for a long time in a submersible environment.

[0027] The stator shielding sleeve of the submersible motor is installed on the inner circular surface of the stator core and is stationary relative to the stator. The stator shielding sleeve is made of PEEK material and has a thickness of 0.5mm. The shielding sleeve has no eddy current loss and magnetic hysteresis loss, and the motor has high efficiency.

[0028] The working medium of the submersible motor is water, and when the motor shaft rotates at high speed, very large water friction loss is generated, so that the loss of the motor is greatly reduced. The length-diameter ratio of the designed motor is 2.1, and the length-diameter ratio of the motor shaft designed by the application is not less than 2. The longer the motor is, the smaller the water wear of the rotor is, and the higher the efficiency of the motor is.

[0029] The end cover of the submersible motor is provided with four sealing ring grooves, and the O-shaped rings are used for static sealing between the shell and the stator shielding sleeve, so that the stator is completely isolated from water, the water entering the stator is prevented from causing insulation short circuit, and the motor is prevented from burning.

[0030] Embodiment 1, Figure 1 It is a self-circulating double-shielded submersible motor for an axial flow pump designed by the application. The designed submersible motor mainly comprises a rear end cover 1, an end cover O-shaped ring 2, an epoxy resin 3, a shell 4, a stator 5, a rotor 6, a front end cover 7, a sand throwing ring 8, a shaft 9, a check ring 10, a graphite bearing 11, a stator O-shaped ring 12, a shielding sleeve 13, a screw 14 and a filter screen 15.

[0031] The two graphite bearings 11 are arranged on the inner sides of the rear end cover 1 and the front end cover 7 respectively; the stator 5 is installed in the interior of the shell 4; the rotor 6 is installed on the shaft 9 and is limited in the axial and radial directions by the bearings 11; the rear end cover 1 and the front end cover 7 are installed at the two ends of the shell 4; the end cover O-shaped ring 2 and the stator O-shaped ring 12 are installed on the rear end cover 1 and the front end cover 7; the shielding sleeve 13 is installed between the stator 5 and the rotor 7; the sand throwing ring 8 is installed on the shaft 9 and is limited in the axial direction by the check ring 10; and the filter screen 15 is installed on the rear end cover 1.

[0032] In some other embodiments, the two graphite bearings 11 are installed with interference on the rear end cover 1 and the front end cover 7 respectively, and the outer circle of the graphite bearings 11 is coated with Loctite holding glue for anti-loosening; the stator 5 is installed with interference on the shell 4; and the rotor 6 is installed with interference on the shaft 9.

[0033] In some other embodiments, the rear end cover 1 and the front end cover 7 are installed on the shell 4 through screws 14, and the screw holes are wired for anti-loosening; the filter screen 15 is provided with internal threads and is installed on the rear end cover 1 through threaded cooperation, and the threads are coated with thread locking glue for anti-loosening.

[0034] With reference to Figure 1 , the stator 5 is filled with epoxy resin 3; the shielding sleeve 13 is sleeved on the inner circle of the stator 5; and the stator 5 is sealed and isolated from the end cover O-ring 2 and the stator O-ring 12 through the epoxy resin 3. Reasonable selection of the sealing ring material, size, and correct size of the installation groove can realize that the stator 5 is in a closed interval and will not be short-circuited and burned due to water entering.

[0035] The gap between the inner circle of the graphite bearing 11 and the outer circle of the shaft 9 is 0.05 mm, and the gap between the stator 5 and the rotor 6 is 0.3 mm. The gap between the outer circle of the screw end of the shaft 9 and the inner circle of the rear end cover 1 is 1 mm. After the submersible motor is powered on, the rotor 6 and the shaft 9 rotate at high speed under the above gap.

[0036] With reference to Figure 2 , the end face of the graphite bearing 11 is provided with five lubricating grooves with a width of 6 mm and a depth of 4 mm, and the inner circle is provided with a spiral lubricating groove. This structure can ensure the lubrication of the end face and the inner circle when the submersible motor works underwater, reduce friction loss, and improve motor efficiency.

[0037] With reference to Figure 1 , Figure 3 , the end of the shaft 9 of the submersible motor is provided with a spiral flow channel. The motor is completely submerged in water during normal operation, and a high pressure is generated between the spiral outer circle of the shaft 9 and the inner circle of the rear end cover 1 during the operation of the motor. The water is driven to flow along the axial direction through the rotating flow channel. On the one hand, it can form a circulation of water in the motor, and the heat dissipation is good. On the other hand, it can clean the impurities entering the motor through the filter screen 15, so that the above working gap remains unobstructed and will not cause jamming.

[0038] With reference to Figure 1 , Figure 4 , the sand throwing ring 8 is in the shape of a "brim" and is installed on the extended end of the shaft 9. When the motor is not working, the sand throwing ring can block the impurities in the water from entering the motor through the gap between the extended end of the shaft 9 and the front end cover 7. When the motor is working, the shaft 9 drives the sand throwing ring 8 to rotate at high speed, which can throw away the impurities in the water, so as to ensure that the impurities in the water do not enter the motor and avoid jamming.

[0039] With reference to Figure 5The submersible motor is provided with a self-circulation flow channel. The working medium water enters the cavity of the rear end cover 1 of the motor through the filter screen 15, and the pressure is generated between the screw force of the shaft 9 and the inner circle of the rear end cover 1, and then flows out through the working gap between the graphite bearing 11 lubricating groove, the stator 5 and the rotor 6. The self-circulation is realized in the submersible motor, which provides good cooling and heat dissipation for the motor, and can clean the impurities in the motor, so that the internal gap of the motor is smooth and will not be stuck.

[0040] The above specific embodiments or cases are only used to explain the technical solutions of the present application, and are not limited to the present application. The parts not described in detail are regarded as conventional technical means or common knowledge in the art. It can be understood by those skilled in the art that: based on the design idea of the present application, the technical solutions recorded in the foregoing embodiments can be modified, or some or all of the technical features can be replaced, and these modified, replaced and modified technical solutions do not deviate from the technical essence of the present application, and should be covered within the protection scope of the present application.

Claims

1. A self-circulating double shielded submersible motor for axial flow pump, characterized by, The motor comprises a rear end cover, a shell, a stator, a rotor, a front end cover, a sand throwing ring, a shaft, a graphite bearing and a shield sleeve. The two graphite bearings are respectively arranged at the inner sides of the rear end cover and the front end cover; the stator is arranged in the shell; the rotor is arranged on the shaft and is limited in the axial and radial directions by the bearing; the rear end cover and the front end cover are respectively arranged at the two ends of the shell; the shield sleeve is arranged between the stator and the rotor and is used for isolating the installation space of the stator; and the sand throwing ring is arranged on the shaft. The inner circle of the graphite bearing and the outer circle of the shaft, and the outer circle of the tail end of the shaft and the inner circle of the rear end cover are in clearance fit; after the submersible motor is powered on, the rotor and the shaft rotate at high speed under the clearance, the shaft of the motor drives the impeller of the axial flow pump to rotate at high speed, and water is discharged in the form of axial flow to form a self-circulation.

2. A self circulating double shielded submersible motor for axial flow pump as claimed in claim 1 wherein, The tail end of the shaft is arranged in the rear end cover and is provided with a spiral flow channel; when the motor works normally, it is completely immersed in water, the outer circle of the spiral structure of the shaft and the inner circle of the rear end cover generate high pressure in the clearance therebetween, and water is driven to flow along the axial direction through the rotating flow channel.

3. A self circulating double shielded submersible motor for axial flow pump as claimed in claim 1 wherein, The sand throwing ring is in the shape of a "brim" and is arranged at the extending end of the shaft; when the motor does not work, the sand throwing ring can block the impurities in the water from entering the motor through the clearance between the extending end of the shaft and the front end cover; when the motor works, the shaft drives the sand throwing ring to rotate at high speed, and the impurities in the water are thrown away from the motor.

4. A self circulating double shielded submersible motor for axial flow pump as claimed in claim 1 wherein, The end face of the graphite bearing is provided with a plurality of lubricating grooves, and the inner circle is further provided with a spiral lubricating groove communicated with the lubricating grooves of the end face.

5. A self circulating double shielded submersible motor for axial flow pump as claimed in claim 1 wherein, A filter screen is further arranged on the rear end cover and is used for filtering external impurities.

6. A self circulating double canned submersible motor for axial flow pump as claimed in claim 1 wherein, The front and rear end covers are provided with a plurality of sealing ring grooves and are respectively sealed by O-rings between the shell and the stator shield sleeve to completely isolate the stator from water.

7. A self circulating double canned submersible motor for axial flow pump as claimed in claim 1 wherein, The stator is filled with epoxy resin.

8. A self circulating double canned submersible motor for axial flow pump as claimed in claim 1 wherein, The length-diameter ratio of the motor shaft is not less than 2.

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