A device and method for disassembling the impeller and auxiliary impeller of a shielded electric pump with small clearance.

Abstract

This invention discloses a small-gap disassembly device and method for a canned motor pump impeller and auxiliary impeller, relating to the field of canned motor pump manufacturing. It solves the problems of difficult disassembly of the impeller and auxiliary impeller, high surface scratch rate, and easy generation of defective products. The impeller disassembly device and auxiliary impeller disassembly device are located at both ends of the stator. The impeller disassembly device includes a baffle, a ring, and a disc. The baffle is positioned in the gap between the impeller and the heat shield. The baffle, ring, and disc are connected sequentially. The auxiliary impeller disassembly device includes a fixing plate, a plate, and hexagonal bolts. The fixing plate is sleeved on the outside of the auxiliary impeller and connected to the plate. A pin is provided at the flow channel opening of the auxiliary impeller, and a screw is provided on the pin, with the screw end face pressing against the fixing plate. A bolt is provided at the center of the plate, with one end of the bolt abutting against the rotor shaft end face. This invention achieves smooth disassembly of the canned motor pump impeller and auxiliary impeller after reducing the mating gap by 50%-75%, and reduces the surface scratch rate from 100% to 0, effectively improving product manufacturing quality.

Description

Technical Field

[0001] This invention relates to the field of shielded electric pump manufacturing technology, specifically to a device and method for disassembling the impeller and auxiliary impeller of a shielded electric pump with small clearance. Background Technology

[0002] To meet the manufacturing requirements of high-precision dynamic balancing for canned motor pump rotors, the product design incorporates reduced clearances between key rotating components such as the impeller and auxiliary impeller to improve rotor dynamic balancing accuracy and reduce vibration and noise in the canned motor pump unit. However, reducing the clearances between the impeller and auxiliary impeller and the rotor presents the following significant problems during disassembly using traditional methods: Firstly, after the clearance between the impeller and auxiliary impeller and the rotor is reduced, the traditional cold disassembly process cannot directly remove the impeller and auxiliary impeller with the small clearance from the rotor by hand. Secondly, if conventional disassembly tools are used to assist in disassembly, disassembly holes need to be added to the impeller and auxiliary impeller. However, due to the limitations of the canned electric pump's own structure, it is not feasible to add disassembly holes to the impeller and auxiliary impeller, so conventional disassembly tools cannot be used.

[0003] Third, if the impeller and auxiliary impeller are forcibly disassembled using a pry bar, it is easy to cause the parts to be bumped and deformed. Furthermore, the wear rate of the mating surfaces after disassembly is as high as 100%, which may even lead to the scrapping of parts, seriously affecting product quality and production schedule.

[0004] Fourth, if conventional induction heating is used or dedicated heating equipment is purchased, the product's own structural space is limited, making it impossible to heat it.

[0005] Therefore, it is necessary to study a device and method for disassembling the impeller and auxiliary impeller of a canned motor pump with small clearances, in order to solve the problem that existing disassembly processes cannot implement small clearance disassembly, realize the design requirement of reducing the mating clearance between the impeller and auxiliary impeller of the canned motor pump, and thus reduce the vibration and noise index of the unit. By studying a new disassembly process, the quality problem of grinding the mating surface of the impeller and auxiliary impeller when forcibly disassembling with small clearances can be solved, providing a reliable process guarantee for improving the manufacturing quality of canned motor pumps. Summary of the Invention

[0006] To address the aforementioned problems of difficult disassembly of the impeller and auxiliary impeller of a shielded electric pump with small clearance, high surface abrasion rate, and easy generation of defective products, this invention proposes a disassembly device and method for the impeller and auxiliary impeller of a shielded electric pump with small clearance. This invention enables smooth disassembly of the impeller and auxiliary impeller after reducing the clearance by 50%-75%, and reduces the surface abrasion rate from 100% to 0, effectively improving product manufacturing quality.

[0007] This invention proposes a small-gap disassembly device for a shielded electric pump impeller and auxiliary impeller, specifically comprising an impeller disassembly device and an auxiliary impeller disassembly device, which are respectively disposed at both ends of the stator. The impeller disassembly device includes several baffles, several double-ended bolts, a ring, and a disc. The baffles are evenly arranged circumferentially in the gap between the impeller and the heat shield. The baffles and the ring are connected, and the ring, double-ended bolts, and disc are connected in sequence. The auxiliary impeller disassembly device includes a fixing plate, several double-ended bolts, a plate, and hexagonal bolts. The fixing plate is sleeved on the outside of the auxiliary impeller and connected to the plate by several double-ended bolts. A pin is provided at the flow channel opening of the auxiliary impeller, and a screw is provided on the pin, with the end face of the screw pressing against the fixing plate. A threaded hole is provided in the center of the plate. The hexagonal bolt is disposed in the threaded hole, with one end fitting against the end face of the rotor shaft.

[0008] Furthermore, the impeller disassembly device also includes an extended hexagonal bolt, which is connected to the rotor shaft head.

[0009] Furthermore, the extended hexagonal bolt is fitted with a washer.

[0010] Furthermore, the impeller disassembly device also includes a support bracket, on which the stator is placed when disassembling the impeller.

[0011] Furthermore, the baffle is a fan-shaped plate.

[0012] Furthermore, the auxiliary impeller disassembly device also includes a round nut, which is located at the rotor external thread platform below the auxiliary impeller.

[0013] Furthermore, the auxiliary impeller disassembly device also includes a second support bracket, on which the stator is placed when disassembling the auxiliary impeller.

[0014] A disassembly method using the aforementioned small-clearance disassembly device for the impeller and auxiliary impeller of a shielded electric pump includes the following steps: Step 1: Place the stator, which contains the rotor and auxiliary impeller, on the support with one end facing down; Step 2: Fit the fixing plate onto the outer diameter of the auxiliary impeller and connect it to the auxiliary impeller with pins and screws; connect the fixing plate and the plate with double-ended bolts; pass the hex bolt through the central threaded hole of the plate and press it against the end face of the rotor shaft; Step 3: Heat the auxiliary impeller hub from the direction of the rotor shaft head with a hot air gun to increase the clearance between the auxiliary impeller hub and the shaft, and remove it by gravity; if it cannot slide down naturally, rotate the hex bolt to apply a pulling force to the auxiliary impeller through the auxiliary impeller removal device to remove it. Step 4: Flip the stator over and place it on the support with the impeller end facing down; Step 5: Install the baffle in the gap between the heat shield and the impeller, and connect the baffle and the disc using double-ended bolts; Step 6: Use a hot air gun to heat the impeller rear hub through the gap between the heat shield and the impeller, increasing the clearance between the impeller rear hub and the shaft platform, allowing it to slide down naturally under gravity for removal; if it cannot slide down naturally, use a tool to tap the disc to remove the impeller.

[0015] The beneficial effects of the small clearance disassembly device and method for a shielded electric pump impeller and auxiliary impeller described in this invention are as follows: (1) The shielded electric pump impeller and auxiliary impeller small gap disassembly device and disassembly method described in this invention, through the segmented fan-shaped L-shaped structure design of the baffle and the combination with the ring, can provide uniform external force to the impeller during disassembly, which solves the problem that the traditional integral structure disassembly tooling cannot be installed to assist disassembly due to the limitation of product structure space, and cannot apply external force to assist disassembly when it is difficult to add disassembly holes and small gap fit disassembly.

[0016] (2) The small-gap disassembly device and method for a shielded electric pump impeller and auxiliary impeller described in this invention utilizes the flow channel opening of the auxiliary impeller itself. A pin is inserted into the flow channel opening and cooperates with the fixing plate, providing a position for applying external force. This solves the problem that during the disassembly of the auxiliary impeller, due to the limitation of product structure space, it is impossible to increase the disassembly hole, and when the small-gap disassembly is difficult, it is impossible to apply external force to assist disassembly. The pin solves the problem that in the assembly of the shielded electric pump, the auxiliary impeller is contained in the sleeve, and the space between the outer diameter of the auxiliary impeller and the inner diameter of the sleeve is narrow, making it impossible to install and implement the disassembly assistance of the traditional integral structure disassembly tooling.

[0017] (3) The small gap disassembly device and disassembly method for the impeller and auxiliary impeller of the shielded electric pump described in this invention optimizes and adjusts the disassembly process of the impeller and auxiliary impeller, changes the horizontal disassembly to the vertical disassembly, adjusts the disassembly sequence of the impeller and auxiliary impeller, and disassembles the auxiliary impeller first, making full use of the axial movement of the shielded electric pump, increasing the distance between the impeller and the heat shield during the disassembly of the impeller, and solving the problem in the traditional disassembly process that, due to the limitation of the product's own structure, the impeller is contained in the heat shield stop, there is no effective disassembly space between the heat shield and the impeller back cover plate, and it is impossible to carry out pull disassembly by installing auxiliary disassembly tools.

[0018] (4) The small clearance disassembly device and disassembly method for the impeller and auxiliary impeller of the shielded electric pump described in this invention adopts a combination of heating and auxiliary pulling disassembly method. The disassembly process method of heating the impeller and auxiliary impeller hub with a hot air gun solves the quality problem of high surface scratch rate when the small clearance is directly disassembled by cold pulling after the impeller and auxiliary impeller clearance is reduced by 50%-75%. It effectively improves the manufacturing quality of the product and provides a reliable process guarantee for the shielded electric pump to reduce the vibration and noise index of the unit. The surface scratch rate is reduced from 100% to 0, which effectively improves the manufacturing quality of the shielded electric pump and provides a reliable guarantee for the shielded electric pump to reduce the vibration and noise index of the unit. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] In the attached diagram: Figure 1 This is a schematic diagram of the impeller disassembly device of the small clearance disassembly device for a shielded electric pump impeller and auxiliary impeller according to the present invention; Figure 2 This is a three-dimensional structural schematic diagram of the impeller disassembly device of the shielded electric pump impeller and auxiliary impeller small clearance disassembly device described in this invention; Figure 3 This is a front view of the baffle of a small clearance disassembly device for a shielded electric pump impeller and auxiliary impeller as described in this invention; Figure 4 This is a cross-sectional view of the baffle of a small clearance disassembly device for a shielded electric pump impeller and auxiliary impeller as described in this invention; Figure 5 This is a front view of the annulus of the small clearance disassembly device for the impeller and auxiliary impeller of a shielded electric pump according to the present invention; Figure 6 This is a cross-sectional view of the annulus of a small clearance disassembly device for a shielded electric pump impeller and auxiliary impeller as described in this invention; Figure 7 This is a schematic diagram of the structure of the auxiliary impeller disassembly device of the shielded electric pump impeller and auxiliary impeller small clearance disassembly device according to the present invention; Figure 8 This is a three-dimensional structural diagram of the auxiliary impeller disassembly device of the shielded electric pump impeller and auxiliary impeller small clearance disassembly device described in this invention; Figure 9 This is a front view of the pin of the small clearance disassembly device for the impeller and auxiliary impeller of a shielded electric pump according to the present invention; Figure 10 This is a side view of the pin of the small clearance disassembly device for the impeller and auxiliary impeller of a shielded electric pump according to the present invention; Among them: 1-Hex bolt, 2-Two hex nuts, 3-Two double-ended bolts, 4-Plate, 5-Pin, 6-Hex socket screw, 7-Fixing plate, 8-Two brackets, 9-Sleeve, 10-Stator, 11-Rotor, 12-Auxiliary impeller, 13-Round nut, 14-Baffle, 15-Ring, 16-Disc, 17-Bolt, 18-One double-ended bolt, 19-One hex nut, 20-Impeller, 21-Heat shield, 22-One bracket, 23-Extended hex bolt, 24-Washer. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. The described embodiments are merely some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] Specific implementation method one: See Figures 1-10 This embodiment is described in detail. The small-gap disassembly device for the impeller and auxiliary impeller of a shielded electric pump described in this embodiment specifically includes an impeller disassembly device and an auxiliary impeller disassembly device. The impeller disassembly device is located at the large flange end of the stator 10, and the auxiliary impeller disassembly device is located at the small flange end of the stator 10. The impeller disassembly device includes several baffles 14, a ring 15, a disc 16, several bolts 17, several double-ended bolts 18, several hexagonal nuts 19, a bracket 22, an extended hexagonal bolt 23, and a washer 24. When disassembling the impeller 20, the large flange end of the stator 10 is placed downwards on the bracket 22. The baffle 14 is a fan-shaped structural plate with an L-shaped radial cross-section, made of stainless steel. The working surface of the baffle 14 is a thin-walled structure, and the baffle 14 has two threaded holes. Several baffles 14 are evenly arranged circumferentially in the gap between the impeller 20 and the heat shield 21, and inserted between the back blades of the impeller 20's rear cover plate. The segmented structure of the baffle 14 can make full use of the narrow gap between the back cover plate and the heat shield 21 between the impeller 20 back blades to insert it, solving the problem that the impeller 20 cannot have more disassembly holes due to its own structural limitations, and that traditional integral structure disassembly tools cannot be inserted from the gap between the end face of the impeller back blades and the end face of the heat shield to carry out auxiliary disassembly.

[0023] The ring 15 is a ring structure made of stainless steel plate. The ring 15 is coaxially sleeved on the outside of the impeller 20. The ring 15 has five sets of 10 through holes, and bolts 17 are installed at the through holes. The ring 15 is connected to the baffle 14 by several bolts 17. The ring 15 connects several baffles 14 into a whole for transmitting tension.

[0024] A disc 16 is located directly below the impeller 20. The disc 16 is a thick-walled plate. The ring 15 has five threaded holes, and the disc 16 has five through holes. One end of the double-ended bolt 18 is connected to the ring 15, and the other end passes through the through hole on the disc 16 and is provided with two hexagonal nuts 19, which connect the double-ended bolt 18 and the disc 16 together. During the impeller disassembly process, the impeller 20 is subjected to a downward pulling force by the counterweight of the disc 16 itself or by applying external force to it.

[0025] The extended hexagonal bolt 23 is connected to the rotor shaft of the rotor 11. A washer 24 is fitted on the extended hexagonal bolt 23. The washer 24 is made of polytetrafluoroethylene. The extended hexagonal bolt 23 and the washer 24 are used to stop the impeller 20 during the heating and disassembly process to prevent it from falling off and being bumped.

[0026] The auxiliary impeller disassembly device includes hexagonal bolts 1, several hexagonal nuts 2, several double-ended bolts 3, plate 4, several pins 5, several internal hexagonal screws 6, fixing plate 7, bracket 8, and round nut 13. When disassembling the auxiliary impeller 12, the small flange end of the stator 10 is placed downwards on the bracket 8. The fixing plate 7 is an annular stainless steel plate, which is sleeved on the outside of the auxiliary impeller 12 and below the sleeve 9. The inner diameter of the fixing plate 7 and the outer diameter of the auxiliary impeller are in a small clearance fit, and several threaded holes are provided on it. The fixing plate 7 is mainly used to transfer the pulling force to the pins 5 acting in the flow channel of the auxiliary impeller 12 during the disassembly process, thus playing the role of transmitting the disassembly pulling force.

[0027] A pin 5 is installed at the inlet of the auxiliary impeller 12 flow channel. Pin 5 is a φ12 cylindrical rod with a square head and an eccentric structure. The square head has a threaded hole. Figures 9-10 As shown, an internal hexagon screw 6 is installed at the threaded hole. The internal hexagon screw 6 is screwed into the threaded hole of the pin 5. By tightening the internal hexagon screw 6, the end face of the screw 6 presses against the fixing plate 7, thereby adjusting the position of the pin 5 and fixing it tightly into the flow channel opening of the auxiliary impeller 12, which is used to limit the fixing plate 7. During the disassembly of the auxiliary impeller, the external force is transmitted to the pin 5 through the fixing plate 7, and the pin 5 directly applies the force to the auxiliary impeller 12. This solves the problem that the auxiliary impeller 12 cannot have more disassembly holes due to its own structural limitations, and that the traditional integral structure disassembly tooling cannot be installed to assist disassembly due to the limitation of the overall assembly space.

[0028] The plate 4 is made of stainless steel and is located directly below the auxiliary impeller 12. The plate 4 has several through holes and a threaded hole in the center. One end of a double-ended bolt 3 is connected to the fixing plate 7, and the other end passes through the through hole in the plate 4 and is connected to the plate 4 via a hexagonal nut 2. A hexagonal bolt 1 is located at the threaded hole in the center of the plate 4, with its end face resting against the rotor shaft end face. During the disassembly of the auxiliary impeller, rotating the hexagonal bolt 1 applies a disassembly pull to the auxiliary impeller 12. The plate 4 transmits the tightening force of the hexagonal bolt 1 to the fixing plate 7, which then transmits the pull force to the pin 5 mounted on the auxiliary impeller, thus achieving the purpose of assisting disassembly. A round nut 13 is located below the auxiliary impeller 12 at the rotor's external thread platform to catch the auxiliary impeller during its disassembly and descent, preventing it from directly falling off and scratching the working surface.

[0029] A disassembly method using the aforementioned small-clearance disassembly device for the impeller and auxiliary impeller of a shielded electric pump includes the following steps: Step 1: Rotate stator 10: Place stator 10, which contains rotor 11 and auxiliary impeller 12, with one end facing down on bracket 2 8.

[0030] Step 2, Installation of Auxiliary Impeller Removal Device: Install the fixing plate 7 of the auxiliary impeller removal device onto the outer diameter of the auxiliary impeller 12. Install the six pins 5 into the flow channel opening of the auxiliary impeller 12 in sequence. Screw the hexagonal screws 6 into the threaded holes of the six pins 5 respectively. Tighten the end face of the hexagonal screws 6 against the fixing plate 7 to secure the pins 5 in the flow channel opening of the auxiliary impeller 12. Then, install the double-ended bolt 2 3 into the threaded hole of the fixing plate 7. Then, pass the plate 4 through the double-ended bolt 2 3 and connect and fix the double-ended bolt 2 3 and the plate 4 with the hexagonal nut 2 2. Pass the hexagonal bolt 1 through the center threaded hole of the plate 4 and press the hexagonal bolt 1 against the end face of the rotor shaft.

[0031] Step 3: Heating and Disassembling the Auxiliary Impeller: Use two hot air guns to heat the hub of the auxiliary impeller 12 from the direction of the rotor shaft head. This causes the hub to expand due to heat, increasing the clearance between the auxiliary impeller 12 and the shaft. Using the counterweight of the auxiliary impeller 12 and the disassembly device, the auxiliary impeller 12 will naturally slide downwards and be removed after heating and expansion. If the clearance is too small, the expansion of the auxiliary impeller will not allow it to slide down naturally. In this case, slowly rotate the hexagonal bolt 1 to apply a downward pulling force to the auxiliary impeller 12 through the disassembly device, ultimately removing the auxiliary impeller 12 from the rotor 11. Remove the auxiliary impeller disassembly device, support the auxiliary impeller 12, remove the round nut 13 below it, and move the auxiliary impeller 12 from the rotor 11 to a clean storage area. This completes the disassembly of the auxiliary impeller 12.

[0032] Step 4: Stator flipping: Flip the stator 10 and place it on the bracket 22 with the large flange end where the impeller 20 is installed facing down.

[0033] Step 5: Impeller disassembly device installation: Insert the five baffles 14 from the impeller disassembly device between the back blades of the impeller 20 through the gap between the heat shield 21 and the impeller 20. Then, fit the ring 15 onto the outer diameter of the impeller and use bolts 17 to fix the five baffles 14 and the ring 15 into a whole. Use double-ended bolts 18 and hexagonal nuts 19 to place the disc 16 below the ring 15. After fitting the extended hexagonal bolt 23 with washers 24, install it into the threaded hole of the rotor shaft head.

[0034] Step Six: Impeller Heating and Disassembly: Use two hot air guns to heat the outer diameter of the rear hub of the impeller 20 through the gap between the heat shield 21 and the impeller 20, increasing the clearance between the rear hub and the shaft. Relying on the counterweight of the impeller 20 and the impeller disassembly device, the impeller 20 will naturally slide downwards and be disassembled after heating and expansion. If the clearance is too small and the impeller 20's thermal expansion is insufficient for it to fall naturally, use a tool to tap the disc 16 to remove the impeller 20 from the rotor. Remove the impeller disassembly device, support the impeller 20, remove the extended hexagonal bolts 23 and washers 24 below it, and move the impeller 20 from the rotor 11 to a clean storage area, completing the impeller 20 disassembly.

[0035] In summary, the small-gap disassembly device and method for a shielded electric pump impeller and auxiliary impeller described in this invention, through the segmented fan-shaped L-shaped structure of the baffle 14 and its combination with the ring 15, can provide a uniform external force to the impeller 20 during disassembly. This solves the problems that, due to the limitations of product structure space, traditional integral structure disassembly fixtures cannot be installed to assist disassembly, and external force cannot be applied to assist disassembly when disassembly is difficult due to the inability to increase disassembly holes and small-gap fit.

[0036] This invention discloses a small-gap disassembly device and method for a shielded electric pump impeller and auxiliary impeller. Utilizing the flow channel opening of the auxiliary impeller 12, a pin 5 is inserted into the flow channel opening and engages with the fixing plate 7, providing a position for applying external force. This solves the problem that during the disassembly of the auxiliary impeller 12, due to space limitations in the product structure, it is impossible to add disassembly holes, and external force cannot be applied to assist disassembly when small-gap disassembly is difficult. The pin also solves the problem that in the assembly of the shielded electric pump, the auxiliary impeller 12 is contained within the sleeve 9, and the space between the outer diameter of the auxiliary impeller 12 and the inner diameter of the sleeve 9 is narrow, making it impossible to install traditional integral disassembly fixtures for assisted disassembly.

[0037] The present invention discloses a small-gap disassembly device and method for a shielded electric pump impeller and auxiliary impeller. By optimizing and adjusting the disassembly process of the impeller 20 and auxiliary impeller 12, the horizontal disassembly is changed to a vertical disassembly. The disassembly sequence of the impeller 20 and auxiliary impeller 12 is adjusted, and the auxiliary impeller 12 is disassembled first. This fully utilizes the axial movement of the shielded electric pump and increases the distance between the impeller 20 and the heat shield 21 during the disassembly of the impeller 20. This solves the problem in the traditional disassembly process where, due to the limitations of the product's own structure, the impeller 20 is contained within the stop of the heat shield 21, and there is no effective disassembly space between the heat shield 21 and the rear cover plate of the impeller 20, making it impossible to perform pull-out disassembly by installing auxiliary disassembly tools.

[0038] This invention discloses a small-gap disassembly device and method for a shielded electric pump impeller and auxiliary impeller. It employs a combined heating and assisted pulling disassembly method, using a hot air gun to heat the hubs of the impeller 20 and auxiliary impeller 12. This method solves the quality problem of high surface scratches on the mating surfaces caused by directly using cold pulling to disassemble the small-gap mating parts after the clearance between the impeller 20 and auxiliary impeller 12 has been reduced by 50%-75%. This effectively improves product manufacturing quality and provides a reliable process guarantee for reducing the vibration and noise levels of the shielded electric pump unit. By reducing the surface scratch rate from 100% to 0, it effectively improves the manufacturing quality of the shielded electric pump and provides a reliable guarantee for reducing the vibration and noise levels of the shielded electric pump unit.

[0039] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the invention. They can also be reasonable combinations of the features described in the above embodiments. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for disassembling the impeller and auxiliary impeller of a shielded electric pump with a small clearance, characterized in that: The device includes an impeller disassembly device and an auxiliary impeller disassembly device, which are respectively located at both ends of the stator (10). The impeller disassembly device includes several baffles (14), several double-headed bolts, a ring (15), and a disc (16). The baffles (14) are evenly arranged circumferentially in the gap between the impeller (20) and the heat shield (21). The baffles (14) are connected to the ring (15), and the ring (15), double-headed bolts, and disc (16) are sequentially connected. Connection; The auxiliary impeller disassembly device includes a fixed plate (7), several double-headed bolts, a plate (4) and a hexagonal bolt (1). The fixed plate (7) is sleeved on the outside of the auxiliary impeller (12) and connected to the plate (4) by several double-headed bolts. A pin (5) is provided at the flow channel opening of the auxiliary impeller (12). A screw is provided on the pin (5), and the end face of the screw rests on the fixed plate (7). A threaded hole is provided in the center of the plate (4). The hexagonal bolt (1) is provided in the threaded hole, and one end is in contact with the end face of the rotor shaft.

2. The small clearance disassembly device for the impeller and auxiliary impeller of the shielded electric pump according to claim 1, characterized in that: The impeller disassembly device also includes an extended hexagonal bolt (23), an extended hexagonal bolt (23) and a rotor shaft head connection.

3. The small clearance disassembly device for the shielded electric pump impeller and auxiliary impeller according to claim 2, characterized in that: A washer (24) is fitted onto the extended hexagonal bolt (23).

4. The small clearance disassembly device for the impeller and auxiliary impeller of the shielded electric pump according to claim 1, characterized in that: The impeller disassembly device also includes a support bracket (22). When disassembling the impeller, the stator (10) is placed on the support bracket (22).

5. The small clearance disassembly device for the impeller and auxiliary impeller of the shielded electric pump according to claim 1, characterized in that: The baffle (14) is a fan-shaped plate.

6. The small clearance disassembly device for the impeller and auxiliary impeller of the shielded electric pump according to claim 1, characterized in that: The auxiliary impeller disassembly device also includes a round nut (13), which is located on the rotor external thread platform below the auxiliary impeller (12).

7. The small clearance disassembly device for the impeller and auxiliary impeller of the shielded electric pump according to claim 1, characterized in that: The auxiliary impeller disassembly device also includes a second bracket (8). When disassembling the auxiliary impeller (12), the stator (10) is placed on the second bracket (8).

8. A disassembly method using the small clearance disassembly device for the impeller and auxiliary impeller of a shielded electric pump as described in claim 1, characterized in that: Includes the following steps: Step 1: Place the stator (10) containing the rotor (11) and auxiliary impeller (12) on the support with one end facing down; Step 2: Fit the fixing plate (7) onto the outer diameter of the auxiliary impeller (12) and connect it to the auxiliary impeller (12) with pins (5) and screws; connect the fixing plate (7) and plate (4) with double-ended bolts; pass the hex bolt (1) through the central threaded hole of plate (4) and press it against the end face of the rotor shaft; Step 3: Heat the hub of the auxiliary impeller (12) from the direction of the rotor shaft head with a hot air gun to increase the clearance between the hub of the auxiliary impeller (12) and the shaft platform, and remove it by gravity; if it cannot slide down naturally, rotate the hexagonal bolt (1) to apply a pulling force to the auxiliary impeller (12) through the auxiliary impeller removal device to remove it. Step 4: Flip the stator (10) and place it on the support with the impeller (20) facing down; Step 5: Install the baffle (14) in the gap between the heat shield (21) and the impeller (20), and connect the baffle (14) and the disc (16) using double-headed bolts; Step 6: Use a hot air gun to heat the rear hub of the impeller (20) through the gap between the heat shield (21) and the impeller (20), so that the clearance between the rear hub of the impeller (20) and the shaft platform increases, and the impeller can be removed by gravity. If it cannot slide down naturally, use a tool to tap the disc (16) to remove the impeller (20).

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