Large-torque variable-frequency speed regulation asynchronous motor for fracturing pump

Abstract

The invention relates to the technical field of motors, in particular to a high-power variable-frequency and variable-speed asynchronous motor for a fracturing pump, which mainly structurally comprises a rotor unit, a stator unit, a front end cover, a rear end cover, a junction box, a fan and the like. The high-voltage design improves the power density of the motor, so that the motor can output higher power under the same volume. On the basis of the electromagnetic principle, coil layout, material selection, structural design and insulation grade are optimized to enhance magnetomotive force, so that the motor can support high current and meet the characteristic of large torque. Radial ventilation and heat dissipation are adopted, so that the heat dissipation area is obviously increased; sufficient cooling air is forcibly conveyed into the engine base through the high-power and high-efficiency cooling fan, so that the cooling air quantity and the heat dissipation area are guaranteed; and four air outlet channels are arranged, so that the heat dissipation effect is further enhanced. Through machine base strengthening, bearing insulation design, high-precision bearing and configuration scheme, lubricating grease optimization, electrical protection measures, puller bolt new design and the like, it is ensured that the fracturing pump can stably operate under various complex working conditions, and the construction efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electric motor, and particularly relates to a large-torque variable-frequency speed-regulating asynchronous motor for fracturing pump. BACKGROUND

[0002] In the field of shale oil and gas exploitation, as a key equipment, the fracturing pump puts forward very high requirements on the power and performance of the driving motor. With the increase of the difficulty of oil exploitation and the fact that the traditional diesel-driven fracturing vehicle has been difficult to meet the working requirements of large-scale fracturing pump, and the inherent shortcomings of mechanical transmission system cannot be avoided.

[0003] 1) Large torque problem: In recent years, the unconventional oil and gas exploration and development in China has rapidly and deeply developed towards the trend of ultra-deep, ultra-high temperature and ultra-high pressure, leading the fracturing process to move towards the direction of high level, large displacement, large sand volume and high sand ratio, and thus putting forward new and higher requirements on the fracturing equipment from the aspects of power load and the like. The traditional fracturing equipment taking diesel engine as the power source generally has the shortcomings of low single-machine power and insufficient torque, and long-time and high-load work is easy to cause mechanical system failure, frequent shutdown and interruption, affect the construction operation time, and the insufficient power and torque output also leads to substandard displacement and affects the construction quality. Therefore, the fracturing equipment needs to have the ability of sustained high-power output and overload capacity under high-load working conditions to cope with high-intensity fracturing working conditions.

[0004] 2) Ventilation and heat dissipation problem: The domestic fracturing construction operation is often long in duration and high in intensity, like the fracturing construction of Jiaoye 27 east platform in Fuling shale gas field, which reaches the level of 24-hour continuous construction without stopping the machine, and the construction pressure is as high as 108Mpa. Especially in summer, the outdoor environment temperature is as high as 40℃, and under the conditions of high temperature, high load and long-time operation, a large amount of heat will be generated in each component of the equipment, and if the heat is not dissipated in time, the performance of the equipment will decrease sharply. Taking the traditional diesel-driven fracturing vehicle as an example, the engine temperature is easy to be too high during long-time operation, which leads to the decrease of power output and the increase of fuel consumption. Therefore, the fracturing equipment needs to have high-efficiency heat dissipation capacity, be equipped with a large-power and high-reliability heat dissipation fan, and the air duct design be optimized to ensure that the heat can be quickly dissipated during long-time high-load operation, maintain the stable operation of the equipment, and ensure the normal progress of the construction operation.

[0005] 3) Reliability and stability problem: During the fracturing operation, under the working conditions of large displacement, large sand volume and high sand ratio, the equipment is in long-time high-load operation, which greatly tests the performance and stability of the equipment. The traditional diesel-driven fracturing truck uses a diesel engine as a power source, which is limited by the power form, mechanical structure and control mode. Under the conditions of high load, complex environment and intelligent operation demand, the problems are prominent. First, in terms of structural reliability, the diesel-driven system drives the fracturing pump through a diesel engine, a gearbox and a transmission shaft. There are many transmission links (such as clutches and gearboxes), and the mechanical wear and energy loss are significant. Long-term operation may cause loosening, abnormal noise and even fracture of the transmission components, increase the risk of shutdown, and increase the maintenance cost and time. In terms of power stability, the power output of the diesel engine depends on fuel injection, combustion efficiency and mechanical transmission. Under high load conditions, insufficient combustion and power fluctuation problems are prone to occur, which leads to unstable displacement and pressure of the fracturing pump, uneven expansion of the fracturing fracture, and greatly affects the construction quality. Therefore, improving the performance and stability of the equipment and perfecting the equipment maintenance system are the key to ensuring the smooth progress of the fracturing operation.

[0006] In summary, with the increase of oil exploitation difficulty and the pursuit of exploitation efficiency, the traditional diesel-driven fracturing truck has been difficult to meet the working requirements of large fracturing pumps. The existing diesel-driven fracturing truck has problems such as large structure, low power density, insufficient torque and poor heat dissipation performance. When operating at high power, the motor is prone to overheating, efficiency decline and even failure shutdown, which seriously affects the continuity and efficiency of the fracturing operation. SUMMARY

[0007] In order to solve the above problems existing in the prior art, the purpose of the present application is to provide a large-torque variable-frequency speed-adjusting asynchronous motor for a fracturing pump.

[0008] The technical scheme adopted by the present application is as follows: A large-torque variable-frequency speed-adjusting asynchronous motor for a fracturing pump, comprising a shell, a rotor unit connected in the shell through a bearing, and a stator unit fixedly connected in the shell, the rotor unit being sleeved in the stator unit; One end of the shell is provided with a cooling fan, and the other end of the shell is provided with a plurality of air outlet covers; The stator unit comprises a stator laminated core, a plurality of stator pull rods are fixedly arranged on the outer circumference of the stator laminated core, the stator pull rods are fixed to the shell, a winding coil is connected in the stator laminated core, the winding coil is divided into U, V and W three phases, and the parallel ends of the three-phase winding coils are connected through a bus ring; The rotor unit comprises a rotating shaft and a rotor laminated core, the rotating shaft is connected with the shell through a bearing, a plurality of rotating shaft ribs are connected between the rotating shaft and the rotor laminated core, a plurality of guide bars are fixedly arranged on the outer circumference of the rotor laminated core, and the ends of the plurality of guide bars are connected through an end ring.

[0009] The electric motor of the present application meets the working requirements of high load in shale oil and gas fracturing construction. The design of high voltage improves the power density of the electric motor, so that it can output more power under the same volume. Starting from the electromagnetic principle, the coil layout, material selection, structure design and insulation grade are optimized to enhance the magnetic motive force, so that the motor can support high current, the insulation grade is as high as 200, the temperature rise margin is large, and the characteristics of large torque are met. And it has wide working condition adaptability and strong overload capacity, can realize stable power output, especially in the working condition of ultrahigh pressure, large displacement, large sand volume and high sand ratio, it can overcome the impact of transient high pressure.

[0010] The electric motor of the present application adopts radial ventilation and heat dissipation, and through the flow guide design, the heat dissipation area and efficiency are significantly improved, the temperature can be kept stable under high temperature, high load and overload operation, the continuous operation ability is strong, the failure caused by overheating is avoided, the reliability and service life of the electric motor are improved, and the energy conversion efficiency and economy are also improved.

[0011] The whole motor is improved through the measures of machine base reinforcement, coil design, ventilation and heat dissipation optimization, bearing insulation design, high-precision bearing and configuration scheme, lubricating grease optimization, electrical protection measures and new design of jacking bolt, so as to achieve a structure with less heat generation, good heat dissipation and stability and reliability. The overall protection grade of the motor reaches IP44, the protection grade of the junction box can reach IP55, and the motor can work long-term in the environment temperature range of-30℃ to +45℃.

[0012] As a preferred scheme of the present application, the shell comprises a machine base, one end of the machine base is connected with a D-end cover, the other end of the machine base is connected with an N-end cover, a D-end bearing is installed between the rotating shaft and the D-end cover, an N-end bearing is installed between the rotating shaft and the N-end cover, the D-end bearing is a self-aligning roller bearing, and the N-end bearing is a cylindrical roller bearing.

[0013] The rotors at both ends are rotatably connected with the front and rear end covers through FAG / SKF high-precision bearings. Different types of bearings are customized according to the stress conditions of the front and rear ends of the rotating shaft. The shaft of the non-driving end has good centering property, high radial load and small axial load, so the cylindrical roller bearing is selected, which has small friction coefficient and low noise. The shaft extension of the driving end is connected with the universal shaft, which may have shaft deflection, heavy load and impact vibration, so the self-aligning roller bearing is selected. It can not only bear high radial load, but also has good self-aligning property, and can automatically adjust the shaft center caused by the deflection or misalignment of the shaft or the shell. Not only the operation reliability of the equipment is improved, but also the noise in the operation process of the motor is effectively reduced, the influence on the construction environment and the workers is reduced, and the environmental protection requirements are met.

[0014] As a preferred scheme of the present application, the N-end end cover is connected with an N-end outer bearing cover for shielding the end of the rotating shaft, and the N-end outer bearing cover is connected with a jacking device for jacking the shaft end of the rotating shaft.

[0015] As a preferred scheme of the present application, the jacking device comprises a limiting support fixed on the N-end outer bearing cover, and a jacking bolt for jacking the shaft end of the rotating shaft is sleeved on the limiting support, the jacking bolt is threadedly connected with the N-end outer bearing cover, and a nut for locking the jacking bolt is threadedly connected with the jacking bolt.

[0016] In order to guarantee the axial movement of the rotor part of the motor during transportation and avoid damage to the parts, a jacking device is designed on the N-end outer bearing cover, three jacking bolts are used to lock the rotating shaft, and foolproof measures are taken. The whole jacking device structure mainly comprises a limiting support, red jacking bolts, a split pin, a nut and a gasket, etc. The limiting support is welded on the N-end outer bearing cover, the jacking bolts pass through the limiting support, the nut and the gasket, etc., and are fixed in the threaded holes of the N-end outer bearing cover. The jacking bolts are designed with hole positions and provided with split pins. The locking principle is as follows: before the motor is operated, the nut is loosened, the red marked bolts are withdrawn, the nut is locked after reaching the appropriate position, in order to prevent the loosening and falling of the lower bolts due to vibration, the split pin is further matched with the limiting support to fix and limit the bolts on the N-end outer bearing cover, thereby reducing the frequency of taking and placing the jacking bolts and the probability of loss; before the equipment is transported, the nut is loosened, the red marked bolts are tightened according to a certain tightening torque, and then the nut is locked, so that the shaft head pressing plate of the rotating shaft can be jacked, and the axial locking of the rotating shaft can be realized.

[0017] As a preferred scheme of the present application, the N-end bearing and the D-end bearing are both provided with bearing sleeves made of high insulation material, and bearing temperature sensors are installed at the N-end bearing and the D-end bearing. The present application uses a double-branch six-wire armored pt100 bearing temperature sensor to monitor the temperature of the motor bearing in real time. When the actual temperature exceeds the warning temperature, the remote alarm system will send an alarm signal, and the bearing temperature will be highlighted in red in the operation interface, so as to avoid that the motor is in an abnormal working state for a long time. The sensor has high precision and high reliability, and outputs signals through independent three-wire lines (a total of six lines), so that when a problem occurs in the current line, the standby line can be connected immediately to ensure normal work, and the armored structure greatly enhances the environmental adaptability.

[0018] As a preferred scheme of the present application, the stator lamination core is provided with stator ventilation sheets between adjacent cores; the stator ventilation sheet comprises a stator ventilation plate, and a stator ventilation channel steel is connected to the stator ventilation plate.

[0019] As a preferred scheme of the present application, the stator pull rod is in arc surface to arc surface interference fit with the inner wall of the base, and the stator pull rod is beveled and welded at the contact position with the end of the base, so that the connection strength of the base and the stator lamination core is greatly strengthened through the interference fit + welding of the stator lamination core.

[0020] As a preferred scheme of the present application, the rotor lamination core is provided with rotor ventilation sheets between adjacent cores; the rotor ventilation sheet comprises a rotor ventilation plate, and a rotor ventilation channel steel is connected to the rotor ventilation plate.

[0021] As a preferred scheme of the present application, the rotor ventilation channel steel is bent at the middle section.

[0022] The rotor ventilation sheet and the stator ventilation sheet are designed approximately the same, but the rotor ventilation channel steel adopts a certain bending angle, so that a "gradually expanding air duct" is formed. When the heat dissipation air flow is blown from the rotor inner cavity to the outer cavity, on the one hand, the air flow speed can be smoothly reduced, the vortex is reduced, the resistance loss and local resistance loss along the way are reduced, and the ventilation efficiency is improved; on the other hand, the high-speed airflow (high dynamic pressure) of the air inlet is quickly sucked into the airflow, the low-speed airflow (high static pressure) of the air outlet forms stable air pressure, pushes the air into the stator winding heat dissipation gap, enhances the scouring ability of the airflow to the heating components, and greatly strengthens the ventilation and heat dissipation capacity.

[0023] As a preferred scheme of the present application, the shell is provided with a main junction box and an auxiliary junction box, the main junction box is connected to three-phase high-voltage lines, and the auxiliary junction box is connected to signal lines or power lines of the heat dissipation fan, a temperature sensor, and an anti-explosion heating belt.

[0024] The motor terminal box is divided into a main terminal box and an auxiliary terminal box, not only avoiding high and low voltage interference and short circuit hidden danger, but also improving personnel operation safety. The main terminal box is connected with three-phase high voltage, and provides power supply for the motor. The overall structure adopts an increased safety protection design, high-strength steel plate material is selected, and good mechanical strength and protection performance are achieved. The protection level reaches IP55, dust can be effectively avoided from entering, and damage caused by water splashing to the inside of the terminal box is prevented, so that the safe and stable operation of internal electrical components is ensured. The cable introduction device adopts an explosion-proof gland, which can prevent pulling out and reliably seal. In terms of electrical performance, the electrical gap of the exposed part of the internal conductor is greater than 100mm, which can greatly reduce the risk of spark, arc and short circuit in the electrical equipment. Grounding columns are designed inside and outside the terminal box, effectively avoiding the risk of electric shock, and further improving the electrical safety performance of the equipment.

[0025] The auxiliary terminal box mainly connects signal lines or power lines of temperature sensors, explosion-proof heating belts and heat dissipation fans. The terminal block interface of the sensor adopts a one-use-one-backup design principle to improve system reliability and fault tolerance. When the main terminal is damaged due to poor contact, oxidation corrosion or external force, the backup terminal can be immediately put into use without power failure.

[0026] The beneficial effects of the present application are as follows: 1. Large torque output: The motor of the present application meets the high load working requirements in shale oil and gas fracturing construction. The design of high voltage improves the power density of the motor, so that it can output more power under the same volume. Starting from electromagnetic principle, the coil layout, material selection, structure design and insulation grade are optimized to enhance the magnetic motive force, so that the motor can support high current, the insulation grade is as high as 200, the temperature rise margin is large, and the characteristics of large torque are met. And it has wide working condition adaptability and strong overload capacity, can realize stable power output, especially in the working condition of super high pressure, large displacement, large sand volume and high sand ratio, it can overcome the impact of transient high pressure.

[0027] 2. Strong ventilation and heat dissipation performance: The motor of the present application adopts radial ventilation and heat dissipation, and through flow guide design, the heat dissipation area and efficiency are significantly improved, the temperature can be kept stable under high temperature, high load and overload operation, the continuous operation ability is strong, the failure caused by overheating is avoided, the reliability and service life of the motor are improved, and the energy conversion efficiency and economy are also improved.

[0028] 3. Stable and reliable performance: the motor as a whole is reinforced by the machine base, the coil design, the ventilation and heat dissipation optimization, the bearing insulation design, the high-precision bearing and configuration scheme, the lubricating grease optimization, the electrical protection measures, the new design of the jacking bolt and other measures, so as to achieve a structure with less heat generation, good heat dissipation and stable reliability. The motor as a whole reaches IP44 protection level, the terminal box reaches IP55 protection level, and can work in the temperature range of-30℃ to +45℃ for a long time. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is the front view of the present application; Figure 2 is the sectional view of the present application; Figure 3 is the structural schematic view of the jacking device; Figure 4 is the assembly structure view of the stator unit; Figure 5 is the structural schematic view of the stator unit; Figure 6 is the structural schematic view of the stator ventilation piece; Figure 7 is the front view of the rotor unit; Figure 8 is the sectional view of the rotor unit; Figure 9 is the structural schematic view of the rotor ventilation piece; Figure 10 is the structural schematic view of the ventilation structure.

[0030] In the figure: 1-stator unit; 2-rotor unit; 3-D end cover; 4-main terminal box; 5- auxiliary terminal box; 6-left side air outlet cover; 7-right side air outlet cover; 8- upper side air outlet cover; 9-radiating fan; 10-bearing temperature sensor; 11-N end cover; 12-air inlet cover; 13-D end bearing; 14-N end bearing; 15-N end inner bearing cover; 16-N end outer bearing cover; 17-jacking device; 101-machine base; 102-stator laminated core; 103-winding coil; 104-connection ring; 105-stator pull rod; 106-laminate; 107-stator ventilation piece; 108-stator ventilation channel steel; 109-stator ventilation plate; 1701-limiting support; 1702-jacking bolt; 1703-split pin; 1704-nut; 201-rotating shaft; 202-rotating shaft rib plate; 203-bar; 204-end ring; 205-rotor pull rod; 206-air guide plate; 207-rotor ventilation piece; 208-rotor ventilation channel steel; 209-rotor ventilation plate; 210-rotor laminated core. DETAILED DESCRIPTION

[0031] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0033] The present application mainly solves the problems of the prior art by the following points: 1) Large torque output: motor torque is the core power demand of fracturing process, and large torque motor has wide working condition adaptability, can realize stable power output, especially in the working condition of ultra-high pressure, large displacement, large sand volume and high sand ratio, can overcome the ability of transient high pressure impact, and the strong torque characteristics ensure that the fracturing pump can stably run in various complex working conditions, and guarantee the construction quality.

[0034] 2) Strong ventilation and heat dissipation performance: in the high heat load working condition of electric drive fracturing construction, the ventilation and heat dissipation of the motor has always been a heat dissipation challenge. The cooling fan and reasonable heat dissipation design ensure the continuous operation ability of the motor under extreme working conditions, maintain stable temperature, avoid failure caused by overheating, improve the reliability and service life of the motor, and also improve the energy conversion efficiency and economy.

[0035] 3) Stable and reliable performance: stable and reliable performance of the motor in various complex working conditions is the core guarantee for the smooth development of electric drive fracturing construction, and its importance runs through multiple dimensions such as construction efficiency, safety, cost and environmental protection. Its role is to ensure the continuity of construction, reduce the whole life cycle cost, improve the operation quality and oil and gas exploitation effect, meet the pursuit of exploitation efficiency, and ensure that the fracturing pump can stably run.

[0036] Overall design of motor: The motor overall achieves compact structure, meets the characteristics of field transportation of fracturing construction, frequent hoisting and small well site. The motor overall protection level reaches IP44, the wiring box protection level can reach IP55, so that the motor can reliably operate in harsh environmental conditions, such as high temperature, low temperature, humidity, sand and dust, and the application range of the motor is expanded. The motor structure is mainly divided into stator assembly, rotor assembly, D end cover 3 (driven end), N end cover 11 (non-driven end), wiring box, cooling fan 9, and the arrangement between each part is compact, and the related structure and position are as shown in Figure 1 The motor is matched with an electric drive fracturing pry and a traditional 2500HP diesel drive fracturing vehicle, and the volume is similar, but the power is increased by more than twice, and under the same fracturing displacement, 50% of the equipment and land area of the entire fracturing operation team can be saved, and the motor front view is as shown in Figure 1 .

[0037] The two ends of the rotor assembly are rotatably connected with the front and rear end covers through FAG / SKF high-precision bearings. Different types of bearings are customized according to the stress conditions of the front and rear shafts 201. The shaft of the non-driven end has good centering, high radial load and small axial load, so a cylindrical roller bearing is selected, which has a small friction coefficient and low noise. The shaft extension of the driven end is connected with the universal shaft, which may have shaft deflection, heavy load and impact vibration, so a self-aligning roller bearing is selected. It can not only withstand high radial load, but also has good self-aligning performance, which can automatically adjust the shaft center caused by the deflection or eccentricity of the shaft or the shell. Not only the reliability of the equipment is improved, but also the noise during the operation of the motor is effectively reduced, the influence on the construction environment and the workers is reduced, and the environmental protection requirements are met.

[0038] The lubrication of the bearing is carried out through the oil injection pipe and the oil discharge pipe on the end cover, and the domestic Kunlun brand high-temperature extreme pressure lubricating grease is selected for high-temperature and heavy-load working conditions. It has excellent performance in wide temperature adaptability and heavy-load operation, reduces the external dependence, and can achieve the dual goals of cost optimization and technical upgrading. The two end bearings form multiple radial labyrinth lubrication seals between the inner seal ring-inner bearing cover and the outer seal ring-outer bearing cover, so that the motor can reliably operate in harsh environmental conditions.

[0039] A bearing sleeve of high insulation material is installed in the N end inner bearing cover 15, and a bearing sleeve of high insulation material is also installed in the N end cover 11. In this way, the insulation treatment of the two sides of the N end bearing 14 is realized, the shaft current path is blocked, the insulation performance of the bearing is effectively guaranteed, and the service life of the bearing is greatly improved.

[0040] The armored pt100 bearing temperature sensor 10 of double support six-wire system is used to monitor the motor bearing temperature in real time. When the actual temperature exceeds the early warning temperature, the remote alarm system will send an alarm signal, and the bearing temperature will be highlighted in red in the operation interface, avoiding the motor in abnormal working state for a long time. The sensor has high precision and high reliability, and outputs signals through independent three-wire lines (a total of six lines). When the current line fails, the standby line can be connected to ensure normal work. The armored structure greatly enhances the environmental adaptability.

[0041] The entire rotor is assembled under the support of the inner seal ring, the inner bearing cover, the bearing, the outer seal ring, the outer bearing cover and the end cover, is positioned by the end cover stop, is sealed by the sealing element, and is fixed by bolts and the entire stator. The N and D end covers 3 are made of high-strength steel and are integrally forged and processed. The design structure is compact and has high mechanical strength. The left side view of the motor is as follows Figure 2 .

[0042] In order to protect the axial movement of the rotor part during the transportation of the motor and avoid damage to the parts, a jacking device 17 is designed on the N end outer bearing cover 16. Three jacking bolts 1702 are used to lock the rotating shaft 201, and foolproof measures are taken. The entire jacking device 17 mainly includes a limiting support 1701, a red jacking bolt 1702, a split pin 1703, a nut 1704 and a gasket. The limiting support 1701 is welded on the N end outer bearing cover 16. The jacking bolt 1702 passes through the limiting support 1701, the nut 1704 and the gasket, and is fixed in the threaded hole of the N end outer bearing cover 16. The jacking bolt 1702 is designed with a hole and a split pin 1703. The locking principle is as follows: before the motor runs, loosen the nut 1704, withdraw the red marked bolt, lock the nut 1704 after reaching the appropriate position, further fix and limit the bolt on the N end outer bearing cover 16 through the split pin 1703 and the limiting support 1701, reduce the frequency of taking and placing the jacking bolt 1702 and the probability of loss, and prevent the vibration from affecting the loosening and falling of the lower bolt. Before the equipment is transported, loosen the nut 1704, tighten the red marked bolt according to a certain tightening torque, and then lock the nut 1704. In this way, the shaft head pressure plate of the rotating shaft 201 can be jacked, and the axial locking of the rotating shaft 201 is realized. The structure of the jacking device 17 is as follows Figure 3 .

[0043] Stator assembly design: The stator assembly part mainly includes the frame 101 and the stator core with winding. The structure is as follows Figure 4The base 101 is welded by high-strength steel, and the inner wall of the core section of the base 101 is a cylindrical structure. The stator core with winding is assembled with the inner wall of the base 101 by 12 stator pull rods 105 which are uniformly distributed on the outer circumference of the stator punching sheet 106. The stator pull rod 105 and the inner wall of the base 101 are in arc-to-arc contact, so that the stator core with winding and the base 101 have sufficient ventilation and heat dissipation cavities. In the past design, the base 101 is heated and then is heat-fitted with the stator core with winding. After cooling, the base 101 shrinks to tightly hold the stator core with winding, so that the interference fit is fixed. In the present application, considering the high-strength vibration impact, the stator pull rod 105 outside the stator core with winding is beveled at the position where it contacts the cylindrical part of the base 101, and an angle weld is welded. Through the interference fit of the stator core with winding + welding, the connection strength of the base 101 and the stator core with winding is greatly strengthened.

[0044] The stator core with winding mainly includes a stator lamination core 102, a winding coil 103, a connecting ring 104, etc., and the structure of the stator core with winding is as shown in Figure 4 The winding coil 103 is embedded in the stator core slot through the clamping slot of the punching sheet 106. The coil winding is divided into U, V and W three phases, and the head end is connected by the bus ring to fix each phase of the coil. Through the "Y" type connection mode, the ends of the three-phase winding are connected to the neutral ring to form a neutral point area. On the one hand, the bearing capacity of the phase voltage can be improved to avoid insulation damage of the winding due to excessive voltage, which is suitable for high-voltage working conditions. On the other hand, the phase current can be reduced, the cross-sectional area of the winding wire can be reduced, the cost and copper loss can be reduced, and it is suitable for high-power working conditions. The whole stator core with winding is subjected to vacuum pressure impregnation for insulation treatment and curing to form a solid insulation layer, which improves the electrical performance, mechanical strength and environmental resistance of the motor. Subsequently, the U, V and W three-phase outgoing wires are passed through the base 101 and connected with the copper bar of the junction box.

[0045] The stator lamination core 102 adopts a segmented design, each segment is made of high-strength and high-permeability silicon steel punching sheet 106, and the size precision and shape tolerance of the parts are strictly controlled. The advanced lamination process achieves the purpose of small tooth expansion, high lamination coefficient and flat lamination, so that the magnetic hysteresis loss and eddy current loss of the stator core are significantly reduced, thereby reducing heat generation and improving material life. Each core is separated by a stator ventilation sheet 107, so that multiple radial air ducts are formed on the stator punching sheet 106, the heat dissipation area is significantly improved, the temperature distribution is more uniform, and the local overheating is greatly improved. Then the core is pressed tightly by the pressure ring at both ends, and the core is fastened as a whole by 12 stator pull rods 105 which are uniformly distributed and welded in the circumference. After welding, the outer circle of the stator pull rod 105 is processed to make it consistent with the arc surface of the inner wall of the cylindrical through hole of the base 101. The structure of the stator lamination core 102 is as shown in Figure 5 .

[0046] The stator ventilation plate 107 consists of an "I"-shaped ventilation channel steel and a stator ventilation plate 109. The ventilation channel steel is welded to the stator ventilation plate 109, with its center line aligned with the center line of the teeth of the stator ventilation plate 109. The number of welded plates matches the number of teeth of the stator ventilation plate 109. This provides excellent support, separates different core sections, and forms a large-area radial air duct. Its structure is as follows: Figure 6 .

[0047] The winding coil 103 is made of high-quality pure copper and corona-resistant insulation material, using advanced winding technology. Based on electromagnetic principles, the coil layout, material selection, structural design, and insulation class are optimized to enhance the magnetomotive force, resulting in excellent electrical performance and the ability to support high currents. Its insulation class reaches up to 200. Therefore, this motor has a large temperature rise margin, strong overload capacity, and can operate normally even under high-intensity working conditions, meeting the characteristics of high torque. Two platinum resistance thermometers (PT100) are evenly embedded in each phase of the stator coil, which can monitor the actual temperature of each phase winding in real time. When the actual temperature exceeds the warning temperature, the remote alarm system will issue an alarm signal, and the bearing temperature will be highlighted in red on the operating interface to prevent the winding coil 103 from burning out under high-temperature operation.

[0048] An explosion-proof heating tape is wrapped around the parallel end of the coil winding for two reasons. First, in cold regions or when the equipment is shut down, condensation is likely to form at the winding end due to the low temperature, which may cause the insulation material to become damp and break down. The explosion-proof heating tape serves to prevent moisture and dry the winding. Second, when the motor starts in a low-temperature environment, the winding resistance increases and the copper loss increases, which may lead to excessive starting current or insufficient torque. By preheating the winding end with the heating tape, the winding impedance can be reduced, and the motor starting performance can be improved (such as reducing starting time and reducing peak starting current).

[0049] Rotor assembly design: The rotor assembly adopts a squirrel-cage structure design, mainly including the rotating shaft 201, rotor stacked iron core 210, etc., with the structure as follows: Figure 7 , Figure 8The shaft 201 is integrally forged by high-strength steel, and six shaft 201 ribs are evenly distributed and welded on the core section. After the rotor laminated core 210 is laminated, a large number of heat dissipation air ducts are formed in the axial direction, and the air deflector 206 is arranged at the D end of the rotor laminated core 210, which not only enhances the air pressure, but also avoids the direct blowing of the air flow in the axial direction, thereby guiding the radial distribution of the air flow and strengthening the heat dissipation of the end of the rotor laminated core 210. The rotor laminated core 210 is also designed in a segmented manner, and each core is laminated by a rotor punching sheet 106 and is spaced by a rotor ventilation sheet 207, so that a plurality of radial air ducts are formed on the rotor punching sheet 106. Each core is fastened into a whole by 12 rotor pull rods 205 evenly distributed on the inner circumference of the punching sheet 106. In order to realize the function of cutting the magnetic induction lines, a plurality of bars 203 are arranged in the outer circumferential clamping groove of the rotor punching sheet 106 to connect each core in series, and the two ends of the bar 203 are connected by an end ring 204. The end ring 204 and the bar 203 made of copper alloy have the advantages of good electrical conductivity, high mechanical strength, corrosion resistance and the like, which are beneficial to improve the efficiency of the motor and the reliability under high load working conditions.

[0050] The rotor ventilation sheet 207 and the stator ventilation sheet 107 are designed in substantially the same way, but the ventilation channel steel of the rotor part adopts a certain bending angle, which forms a "gradually expanding air duct". When the heat dissipation air flow blows from the inner cavity to the outer cavity of the rotor, on the one hand, the air flow velocity can be smoothly reduced, the vortex can be reduced, the resistance loss and local resistance loss along the way can be reduced, and the ventilation efficiency can be improved; on the other hand, the high-speed airflow (high dynamic pressure) at the inlet quickly absorbs the airflow, the low-speed airflow (high static pressure) at the outlet forms stable air pressure, and the airflow is pushed into the stator winding heat dissipation gap to enhance the scouring ability of the airflow to the heating components, greatly enhancing the ventilation and heat dissipation capacity. The structure of the rotor ventilation sheet 207 is as shown in Figure 9 .

[0051] Connection box design: The motor connection box is divided into a main connection box 4 and an auxiliary connection box 5, which not only avoids high and low voltage interference and short circuit hidden danger, but also improves the safety of personnel operation. The main connection box 4 connects three-phase high voltage to provide power for the motor, and the overall structure adopts an increased safety protection design, uses high-strength steel plate material, has good mechanical strength and protection performance, and has a protection level of IP55, which can effectively prevent dust from entering and prevent water splashing from damaging the inside of the connection box, ensuring the safe and stable operation of the internal electrical components. The cable inlet device adopts an explosion-proof gland, which can prevent pulling out and reliably seal. In terms of electrical performance, the electrical gap of the exposed part of the internal conductor is greater than 100mm, which can greatly reduce the risk of sparks, arcs and short circuits generated inside the electrical equipment. Grounding columns are designed inside and outside the connection box, effectively avoiding the risk of electric shock, and further improving the electrical safety performance of the equipment.

[0052] The auxiliary terminal box 5 mainly connects the signal lines or power lines of the temperature sensor, explosion-proof heating belt and heat dissipation fan 9. The terminal block interface of the sensor is designed with one main and one backup to improve the system reliability and fault tolerance. When the main terminal is interrupted due to poor contact, oxidation corrosion or external damage, the backup terminal can be immediately put into use without power interruption.

[0053] Ventilation and heat dissipation design: The motor adopts radial ventilation and heat dissipation, which significantly improves the heat dissipation area. The cooling fan with high power and high efficiency forcibly delivers cooling air into the base 101. The air inlet is provided with a detachable moisture-proof filter, a mosquito screen and the like to prevent impurities from entering the motor. The cooling air flows to the rear end of the rotor lamination core 210, then flows through the air cavity of the rotor shaft 201, and part of the cooling air flows through the air cavity of the rotor ventilation piece 207, the air cavity of the stator ventilation piece 107 and the outer wall cavity of the stator core with winding, to carry away the heat of the rotor punching piece 106 and the stator punching piece 106. Another part of the cooling air flows to the front end through the air cavity of the rotor shaft 201, is guided by the air deflector 206, and carries away the heat of the front end surface of the rotor lamination core 210. To enhance the heat dissipation effect, the motor has four air outlets, which are the upper air outlet cover 8, the right air outlet cover 7, the left air outlet cover 6 and the air outlet at the bottom of the front end of the base 101, to ensure the temperature stability of the motor during long-time operation, avoid overheating and improve the reliability and service life of the motor. The whole heat dissipation direction is as follows Figure 10 .

[0054] The motor of the present application meets the high load working requirements in shale oil and gas fracturing construction. The high voltage design improves the power density of the motor, enabling it to output more power in the same volume. Starting from electromagnetic principles, the coil layout, material selection, structure design and insulation level are optimized to enhance the magnetomotive force, so that the motor can support high current, with an insulation level of 200 and a large temperature rise margin, meeting the characteristics of large torque. It also has wide working condition adaptability and strong overload capacity, can realize stable power output, especially in super-high pressure, large displacement, large sand volume and high sand ratio working conditions, can overcome the impact of transient high pressure.

[0055] The motor of the present application adopts radial ventilation and heat dissipation, and through the flow guide design, the heat dissipation area and efficiency are significantly improved, which can maintain stable temperature under high temperature, high load and overload operation, has strong continuous operation ability, avoids overheating and improves the reliability and service life of the motor, and also improves the energy conversion efficiency and economy.

[0056] The motor as a whole is reinforced by the base 101, the coil is designed, the ventilation and heat dissipation is optimized, the bearing insulation is designed, the high-precision bearing and configuration scheme are configured, the lubricating grease is optimized, the electrical protection measures are taken, the top bolt 1702 is newly designed and the like, so that a structure with less heat generation, good heat dissipation, stability and reliability is achieved, the protection level of the motor as a whole reaches IP44, the protection level of the terminal box can reach IP55, and the motor can work in the environment temperature range of-30 DEG C to +45 DEG C for a long time.

[0057] The present application is not limited to the above-mentioned optional embodiments, anyone can derive other various forms of products under the inspiration of the present application, but regardless of any changes in its shape or structure, any technical solutions falling within the scope defined by the claims of the present application fall within the protection scope of the present application.

Claims

1. A large torque variable frequency speed regulation asynchronous motor for fracturing pump, comprising a shell, a rotor unit (2) is connected in the shell through a bearing, a stator unit (1) is fixedly connected in the shell, and the rotor unit (2) is sleeved in the stator unit (1); characterized in that: one end of the shell is provided with a cooling fan (9), and the other end of the shell is provided with a plurality of air outlet covers; the stator unit (1) comprises a stator laminated core (102), a plurality of stator pull rods (105) are fixedly connected to the outer circumference of the stator laminated core (102), the stator pull rods (105) are fixed to the shell, a winding coil (103) is connected in the stator laminated core (102), the winding coil (103) is divided into U, V and W three phases, and the parallel ends of the three-phase winding coils (103) are connected through a collector ring; the rotor unit (2) comprises a rotating shaft (201) and a rotor laminated core (210), the rotating shaft (201) is connected with the shell through a bearing, a plurality of rotating shaft (201) ribs are connected between the rotating shaft (201) and the rotor laminated core (210), a plurality of guide bars (203) are fixedly connected to the outer circumference of the rotor laminated core (210), and the ends of the guide bars (203) are connected through an end ring (204).

2. A large-torque variable-frequency variable-speed asynchronous motor for fracturing pumps according to claim 1, characterized in that: the shell comprises a base (101), one end of the base (101) is connected with a D-end end cover (3), the other end of the base (101) is connected with an N-end end cover (11), a D-end bearing (13) is arranged between the rotating shaft (201) and the D-end end cover (3), an N-end bearing (14) is arranged between the rotating shaft (201) and the N-end end cover (11), the D-end bearing (13) is a self-aligning roller bearing, and the N-end bearing (14) is a cylindrical roller bearing.

3. A large-torque variable-frequency variable-speed asynchronous motor for fracturing pumps, according to claim 2, characterized in that: the N-end end cover (11) is connected with an N-end outer bearing cover (16) for shielding the end of the rotating shaft (201), and the N-end outer bearing cover (16) is connected with a jacking device (17) for jacking the shaft end of the rotating shaft (201).

4. A large-torque variable-frequency variable-speed asynchronous motor for fracturing pumps according to claim 3, characterized in that: the jacking device (17) comprises a limiting support (1701) fixed to the N-end outer bearing cover (16), a jacking bolt (1702) for jacking the shaft end of the rotating shaft (201) is sleeved on the limiting support (1701), the jacking bolt (1702) is threadedly connected with the N-end outer bearing cover (16), and a nut (1704) for locking the jacking bolt (1702) is threadedly connected with the jacking bolt (1702).

5. A large-torque variable-frequency variable-speed asynchronous motor for fracturing pumps according to claim 2, characterized in that: the N-end bearing (14) and the D-end bearing (13) are both provided with a bearing sleeve made of high insulation material, and a bearing temperature sensor (10) is arranged at the positions of the N-end bearing (14) and the D-end bearing (13).

6. A large-torque variable-frequency adjustable-speed asynchronous motor for fracturing pumps according to claim 1, characterized in that: defining a stator ventilation piece (107) between adjacent stator laminated cores (102); the stator ventilation piece (107) comprises a stator ventilation plate (109), and the stator ventilation plate (109) is connected with a stator ventilation channel steel (108).

7. A large-torque variable-frequency variable-speed asynchronous motor for fracturing pumps according to claim 2, characterized in that: the stator pull rods (105) and the inner wall of the base (101) are in arc-to-arc interference fit, and the contact parts of the stator pull rods (105) and the end of the base (101) are beveled and welded with an angle weld.

8. A large-torque variable-frequency adjustable-speed asynchronous motor for fracturing pumps according to claim 1, characterized in that: The rotor lamination core (210) is provided with rotor ventilation fins (207) between adjacent cores; the rotor ventilation fin (207) comprises a rotor ventilation plate (209), and a rotor ventilation channel steel (208) is connected to the rotor ventilation plate (209).

9. A large-torque variable-frequency adjustable-speed asynchronous motor for fracturing pumps according to claim 8, characterized in that: The middle section of the rotor ventilation channel steel (208) is bent.

10. A high-torque variable frequency adjustable-speed induction motor for fracturing pumps according to any one of claims 1 to 9, characterized in that: The shell is provided with a main junction box (4) and an auxiliary junction box (5), the main junction box (4) is connected with three-phase high-voltage lines, and the auxiliary junction box (5) is connected with signal lines or power lines of a heat dissipation fan (9), a temperature sensor and an anti-explosion heating belt.

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