A rotor assembly for a canned motor pump and a manufacturing method thereof

Abstract

The present application relates to the technical field of canned pump production and manufacturing, and discloses a rotor assembly for a canned electric pump, wherein an injection molding port connected to a magnet slot is reserved at the top of the rotor core, and multiple groups of conductor slots are arranged on the rotor core along the circumference of the rotor core, wherein round copper bars are arranged in the conductor slots, and filling slots are arranged on the side of some conductor slots facing the magnets, and the conductive bars of the cast aluminum squirrel cage are composed of round copper bars and cast aluminum bars in the filling slots. The Q-axis inductance / D-axis inductance value is made greater than 3, thereby greatly improving the proportion of magnetic resistance torque in the electromagnetic torque, thereby reducing the cost of permanent magnet materials of the motor, that is, reducing the cost of the motor. Secondly, the rotor assembly of the present invention proposes a three-axis punching sheet structure design, which reduces the complexity of the punching sheet mold, and the other two punching sheet slot types are included in the main punching sheet slot type, so that the high-speed stamping process only needs to control the stamping slider of the corresponding slot type to achieve the stamping of different punching sheets.

Description

Technical Field

[0001] The present application relates to the technical field of canned motor pump production and manufacturing, and in particular to a rotor assembly for a canned motor pump and a manufacturing method thereof. Background Art

[0002] At present, most household canned motors use asynchronous motors. Due to their low power and large air gap, asynchronous motors have low efficiency. If speed-regulating permanent magnet synchronous motors are used to improve motor efficiency, not only will the cost of the motor itself increase, but the drive cost will also increase, making the cost-effectiveness of improving efficiency low.

[0003] When household canned electric pumps use asynchronous starting permanent magnet synchronous motor technology, the starting current during the starting process is usually 4-7 times the rated current, so irreversible demagnetization is easily produced during the process; the larger air gap of the canned motor will also require more rare earth permanent magnets for excitation, resulting in higher magnetic steel costs. At the same time, the larger air gap will also greatly reduce the motor's ability to migrate to synchronization after asynchronous starting. Summary of the invention

[0004] The present application proposes a rotor assembly for a shielded electric pump and a manufacturing method thereof, which is suitable for low-power household motors. It can greatly increase the proportion of reluctance torque in electromagnetic torque, reduce the cost of permanent magnet materials of the motor, that is, reduce the cost of the motor. At the same time, permanent magnets are directly formed in the rotor core by injection molding, thereby improving the stability of the rotor during operation.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solution: a rotor assembly for a canned electric pump, comprising a rotor core pressed by stamping sheets, a metal shaft running through the middle of the rotor core, and a die-cast aluminum squirrel cage:

[0006] Along the radial direction of the rotor core, the rotor core is provided with four layers of magnet slots, a magnetic channel is formed between two magnet slots, and an injection ferrite formed by injection molding of ferrite is provided in the magnet slots, and an injection port connected to the magnet slots is reserved at the top of the rotor core;

[0007] Along the circumference of the rotor core, a plurality of groups of conductor slots are provided on the rotor core, round copper bars are provided in the conductor slots, and filling slots are provided on the side of some conductor slots facing the magnets. The molten aluminum can flow from one end of the rotor core to the other end along the filling slots, and the conductive bars of the cast aluminum squirrel cage are composed of round copper bars and cast aluminum bars in the filling slots.

[0008] Furthermore, the rotor core is composed of main punches, rotor middle section punches and end face section punches. The end face section punches constitute the ends of the rotor core, the rotor middle section punches constitute the middle section of the rotor core, and other areas are composed of main punches. The magnet slots are arranged on the main punches and the rotor middle section punches. The rotor middle section punches are provided with injection runner grooves connecting the middle three layers of magnet slots, and the middle parts of the end face section punches are provided with axially connected injection feed grooves.

[0009] Furthermore, an open slot is provided every 1-3 conductor slots, and the remaining conductor slots are closed slots.

[0010] Furthermore, the shaft tube is provided with a cavity at the axis of the shaft tube, and the outer wall of the shaft tube is provided with two groups of relative movable grooves, the movable grooves are movably connected with vibration columns, the movable grooves are connected to a pulse air source through the cavity, the pulse air source intermittently drives the vibration column to extend, and an elastic pull rope that can pull the vibration column to contract is provided between the two vibration columns, and during the interval of air supply, the vibration column contracts under the elastic force of the elastic pull rope.

[0011] Furthermore, the insertion depth of the vibration column is aligned with the injection runner grooves on both sides, a capsule is provided between the vibration column and the bottom of the movable groove, and two ends of the capsule are fixedly connected to the bottom of the movable groove and the bottom of the vibration column respectively.

[0012] Furthermore, a limiting groove is provided near the mouth of the movable groove, and an elastic telescopic limiting block is provided at the bottom of the outer side wall of the vibration column. When the telescopic limiting block slides into the limiting groove, it can limit the telescopic limiting block from sliding out.

[0013] Furthermore, an absorption groove is provided on one side of the buffer absorber, an elastic bag is provided on the absorption groove, and the absorption groove is filled with an elastomer. When the injection liquid is filled, the elastic bag can absorb the vibration pressure of the vibrating member.

[0014] A method for manufacturing a rotor assembly for a canned motor pump, comprising the steps of:

[0015] S1: The rotor core is obtained by high-speed stamping of silicon steel sheets, wherein the end segment punching sheets, the middle segment punching sheets and the main punching sheets are placed in a set order and quantity;

[0016] S2: the rotor core is pressed into a round copper bar to obtain a rotor assembly 1;

[0017] S3: Rotor component 1 is die-cast in an aluminum casting mold to obtain rotor component 2;

[0018] S4: turning the outer diameter of rotor component 2 to obtain rotor component 3;

[0019] S5: inserting a metal shaft into the rotor component three, and using ferrite material for injection molding to obtain a rotor component four;

[0020] S6: Rotor assembly 4 is pressed into the stainless steel shielding sleeve 7 to obtain rotor assembly 5;

[0021] S7: Both ends of the rotor assembly 5 are pressed into the stainless steel cover plate 1 to obtain the rotor assembly 6;

[0022] S8: welding the upper and lower ends of the rotor assembly 6 to obtain the rotor assembly 7;

[0023] S9: The rotor assembly 7 is magnetized as a whole to obtain the rotor assembly of the present invention.

[0024] Furthermore, in step S5, during injection molding, one end of the cavity is blocked and the other end is connected to a high-frequency pulse gas source, and the expansion and contraction of the vibration column is used to achieve vibration while injection molding, so as to vibrate out the bubbles in the injection liquid and make the injection liquid dense.

[0025] Furthermore, after the injection of the molding liquid is completed, the injection port is blocked, and an appropriate air pressure is maintained in the cavity, and a stable pressure is maintained through the pressure of the vibrating column.

[0026] Beneficial effects of the present invention:

[0027] The present application provides a rotor assembly for a shielded electric pump and a manufacturing method thereof. The present invention proposes a multi-layer injection-molded ferrite pole structure. Through a reasonable multi-layer pole design, the amount of ferrite permanent magnets used is guaranteed and a large difference in the magnetic resistance of the D-axis magnetic circuit is made, so that the Q-axis inductance / D-axis inductance value is greater than 3, thereby greatly increasing the proportion of magnetic resistance torque in the electromagnetic torque, thereby reducing the cost of permanent magnet materials for the motor, that is, reducing the cost of the motor.

[0028] Secondly, the rotor assembly of the present invention proposes a three-axis punching sheet structure design, which reduces the complexity of the punching sheet mold. The other two punching sheet slots are included in the main punching sheet slot, so that during the high-speed punching process, only the punching slider of the corresponding slot type needs to be controlled to achieve the punching of different punching sheets. At the same time, the design of the rotor end face punching sheet prevents the aluminum from flowing into the magnet slot during the cast aluminum cage process. The design of the rotor middle section punching sheet enables the ferrite material to be smoothly injected from the fourth magnet slot into the second and third magnet slots during the rotor ferrite injection molding. The directly formed magnets and cages make the rotor assembly a whole, which improves the reliability and stability of the structure compared to assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which constitute a part of the specification, illustrate the embodiments disclosed in the present application and, together with the description, serve to explain the principles disclosed in the present application.

[0030] The present application can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0031] Figure 1The figure is an exploded view of a rotor assembly for a canned motor pump;

[0032] Figure 2 The figure is an outline diagram of a rotor assembly for a canned motor pump;

[0033] Figure 3 A top view of a rotor assembly for a canned motor pump;

[0034] Figure 4 It is a side view of a rotor assembly for a canned motor pump;

[0035] Figure 5 A schematic diagram of a main punch in a rotor assembly for a canned motor pump;

[0036] Figure 6 It is a schematic diagram of a middle section punching sheet in a rotor assembly for a canned motor pump;

[0037] Figure 7 It is a schematic diagram of an end face segment punching sheet in a rotor assembly for a canned motor pump;

[0038] Figure 8 A schematic diagram of the magnetic circuit of the DQ axis in a rotor assembly for a canned electric pump;

[0039] Fig. 9 It is a front view of a metal shaft in a rotor assembly for a canned motor pump;

[0040] Fig.10 It is a three-dimensional view of a metal shaft in a rotor assembly for a shielded electric pump. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. Embodiment 1

[0042] like Figure 1-Figure 4As shown, a rotor assembly for a canned electric pump includes a stainless steel cover plate 1, a cast aluminum cage 2, a metal shaft 3, an injection molded ferrite 4, a rotor core 5, a round copper bar 6 and a stainless steel shielding sleeve 7. The outer diameter of the rotor, that is, the outer diameter of the cast aluminum cage is 40-70 mm. The outer surface of the rotor assembly is a welded sealing structure to prevent the canned electric pump medium from contacting the rotor core 5 and causing the core to rust. The stainless steel cover plate 1, the stainless steel shielding sleeve 7 and the metal shaft 3 form a welded structure, and the welding position is the contact surface between the three. The outer circumference of the cast aluminum cage 2 is provided with a number of aluminum columns, and the upper and lower ends are aluminum rings. The injection molded ferrite 4 is provided with a four-layer magnet structure, the first layer of magnets 41, the second layer of magnets 42, the third layer of magnets 43 and the fourth layer of magnets 44, wherein the second layer of magnets 42, the third layer of magnets 43 and the fourth layer of magnets 44 are connected as a whole in the axial middle section of the rotor. The rotor core 5 is a multi-layer punching sheet structure, and the two end areas of the rotor core are composed of a small number of rotor end face punching sheets 53, and further, the number of each end is 1 to 6. The axial middle area of ​​the rotor core is composed of a small number of rotor middle section punching sheets 52, and further, the number is 2 to 12, and the other areas of the rotor core are composed of a large number of rotor main punching sheets 51.

[0043] like Figure 5 The main punch 51 is provided with a first layer of magnet slots 5101, a second layer of magnet slots 5102, a third layer of magnet slots 5103, a fourth layer of magnet slots 5104, a first conductor slot 5105, a second conductor slot 5106, a third conductor slot 5107, a fourth conductor slot 5108, a fifth conductor slot 5109, a sixth conductor slot 5110 and a seventh conductor slot 5111. The first conductor slot 5105 is filled with a cast aluminum bar and a round copper bar, and is a closed slot, and the second conductor slot 5106, the third conductor slot 5107, the fifth conductor slot 5109 and the sixth conductor slot 5110 are filled with a cast aluminum bar and a round copper bar, and are open slots. The conductor filled in the fourth conductor slot 5108 is a round copper bar, and it is a closed slot. The conductor filled in the seventh conductor slot 5105 is a cast aluminum bar and two round copper bars, and it is a closed slot. The open slot is convenient for saturating the cast aluminum. In addition, if the conductor slot near the magnet is open, it can also reduce the leakage magnetic flux of the permanent magnet. The conductor slot is closed to ensure the structural strength.

[0044] like Figure 5 , the distance between the first conductor slot 5105 and the first layer of magnet slots 5101 is set to L1, the distance between the third conductor slot 5107 and the second layer of magnet slots 5102 is set to L2, the distance between the fifth conductor slot 5109 and the third layer of magnet slots 5103 is set to L3, the distance between the seventh conductor slot 5111 and the fourth layer of magnet slots 5104 is set to L4, and 0.2mm≤L1≤0.6mm, 0.2mm≤L2≤0.6mm, 0.2mm≤L3≤0.6mm, 0.2mm≤L4≤0.6mm, and the pole arc angle range of the first layer of magnet slots 5101 is 20 degrees to 40 degrees.

[0045] The second layer magnet slots 5102 and the third layer magnet slots 5103 are designed with equal slot widths, with the distance between points ab set to d1, the distance between points bc set to d2, the distance between points cd set to d3, the distance between points de set to d4, the distance between points ef set to d5, the distance between points fg set to d6, the distance between points gh set to d7, and the distance between points kj set to d8. Then 1.5mm≤d7<d3<d5<d8 / 2<d1≤6mm, 2mm≤d4≤d6<d2<d1.

[0046] like Figure 6 The rotor middle section punching sheet 52 includes an injection molding runner groove 521 structure, and the injection molding runner groove 521 connects the second layer magnet groove 5102, the third layer magnet groove 5103 and the fourth layer magnet groove 5104 into one, realizing an integrated injection molding structure. In the punching sheet structure, the two first layer magnet grooves 5101 on the upper and lower sides are separately molded as one by the injection molding ports on the side.

[0047] like Figure 7 The rotor end face section punching sheet 53 includes an injection molding feed slot 531 structure, wherein the injection molding feed slot 531 is completely contained in the fourth layer magnet slot 5104 in the plane shape. The dotted circle 21 is the schematic outline of the inner circle of the cast aluminum cage 2 end ring, and the injection molding feed slot 531 in the plane view should meet the area within the dotted circle 21. The dotted circle 31 is the schematic outline of the metal shaft 3, and the area between the injection molding feed slot 531 and the dotted circle 31 is the injection molding feeding area of ​​the injection molding ferrite 4.

[0048] like Figure 8 In the D-axis magnetic circuit, due to the presence of multiple layers of magnet slots, the D-axis magnetic resistance is large, while in the Q-axis magnetic circuit, the magnetic lines of force can smoothly pass through the iron core material between the magnet slots to form a magnetic circuit, making the Q-axis magnetic resistance small. The DQ-axis magnetic circuit forms a large magnetic resistance, thereby generating the motor reluctance torque, which together with the permanent magnet torque formed by the ferrite permanent magnet constitutes the motor electromagnetic torque. Embodiment 2

[0049] Since the injection molding magnet material is made of a composite mixture of magnetic powder and plastic adhesive, the weight ratio of magnetic powder is more than about 85%, and the weight ratio of plastic adhesive is only about 10%. Therefore, the injection molding magnet material is different from the general injection molding plastic. The fluidity of magnetic materials is much worse than that of ordinary engineering plastics, and the injection molding filling property is very poor. Therefore, when injection molding some products with complex structures and thick walls, insufficient filling is prone to occur, and sometimes a large number of pores will occur inside the product. In order to reduce this phenomenon, the rotor assembly is further improved on the basis of Example 1.

[0050] like Figure 9-10As shown, the metal shaft 3 includes a shaft tube 31, a cavity 32 is provided at the axis of the shaft tube 31, a buffer absorber 33 and a vibrator 34 are sleeved on the outer wall of the shaft tube 31, a stopper and a threaded section are provided on the side wall of the shaft tube 31, the buffer absorber 33 and the vibrator 34 are integrally arranged, and a nut presses the buffer absorber 33 and the vibrator 34 onto the stopper.

[0051] The vibrating member 34 includes a movable groove 341 connected to the cavity 32, the movable groove 341 extends into the side wall of the shaft tube 31 and is close to the cavity 32. The movable groove 341 is provided with two groups, corresponding to the injection runner grooves 521 on both sides. A vibration column 342 is movably connected in the movable groove 341. A capsule 344 is provided between the vibration column 342 and the shaft tube 31. The bottom of the capsule 344 is fixedly connected to the bottom of the movable groove 341. The capsule 344 is connected to the cavity 32, and the top of the capsule 344 is fixedly connected to the vibration column 342. The expansion and contraction of the capsule 344 can drive the vibration column 342 to move. The end connection of the capsule 344 can be fixed by an adhesive. The two vibration columns 342 are fixed and can be fixed by setting other structures such as a clamping structure. An elastic pull rope 343 is connected between the tops of the two vibration columns 342. When the cavity 32 is connected to a pulsed high-pressure gas source, the capsule 344 expands under the air pressure and contracts under the elastic force of the elastic pull rope 343, driving the vibration column 342 to reciprocate and realize high-frequency vibration. The bubbles generated by the injection molding are made to overflow through vibration. At the same time, after the injection molding is completed, the air pressure is transferred to the injection molding liquid through the vibration column 342 to realize controllable pressure maintenance. The controllable pressure maintenance can further reduce bubbles and avoid the generation of burrs. The head of the vibration column 342 is provided with a guide protrusion to increase the vibration influence range.

[0052] A limiting groove 346 is provided near the mouth of the movable groove 341, and an elastic telescopic limiting block 345 is provided at the bottom of the outer wall of the vibration column 342. When the telescopic limiting block 345 slides into the limiting groove 346, it can limit the sliding out of the limiting groove 346, thereby limiting the amplitude of vibration, avoiding excessive amplitude, squeezing the injection liquid, and generating burrs. The extension of the vibration column 342 can extend along the injection molding runner groove 521 to further increase the vibration range. For ease of assembly, the limiting groove 346 is connected to a shallow groove extending to the bottom of the movable groove 341, and the vibration column 342 is inserted into the shallow groove with a staggered state. After being inserted into the bottom, the telescopic limiting block 345 is aligned with the shallow groove by rotation.

[0053] An absorption groove 331 is provided on one side of the buffer absorber 33, and an elastic bag 332 is provided on the absorption groove 331. The absorption groove 331 is filled with an elastomer. When the injection liquid is full, the elastic bag 332 absorbs the vibration pressure of the vibrating member 34, increases the duration of vibration bubble removal, and further reduces bubbles. The elastic bag 332 and the movable groove 341 are staggered. Embodiment 3

[0054] A method for manufacturing a rotor assembly for a canned motor pump comprises the following steps:

[0055] S1: The rotor core 5 is obtained by high-speed stamping of silicon steel sheets, wherein the end segment punching sheets 53, the middle segment punching sheets 52 and the main punching sheets 51 are placed in a set order and quantity;

[0056] S2: the rotor core 5 is pressed into the round copper bar 6 to obtain a rotor assembly 1;

[0057] S3: Rotor component 1 is die-cast in an aluminum casting mold to obtain rotor component 2;

[0058] S4: turning the outer diameter of rotor component 2 to obtain rotor component 3;

[0059] S5: inserting the metal shaft 3 into the rotor component 3, and using ferrite material for injection molding to obtain the rotor component 4;

[0060] S6: Rotor assembly 4 is pressed into the stainless steel shielding sleeve 7 to obtain rotor assembly 5;

[0061] S7: Both ends of the rotor assembly 5 are pressed into the stainless steel cover plate 1 to obtain the rotor assembly 6;

[0062] S8: welding the upper and lower ends of the rotor assembly 6 to obtain the rotor assembly 7;

[0063] S9: The rotor assembly 7 is magnetized as a whole to obtain the rotor assembly of the present invention.

[0064] Compared with the traditional canned motor pump asynchronous motor rotor manufacturing process, only the inserting round copper bars, ferrite injection molding and rotor magnetization processes are added, so the process cost does not increase significantly and the entire manufacturing process is easy to implement. Embodiment 4

[0065] On the basis of Example 3, in Step S5 of Example 4, during injection molding, one end of the cavity 32 is blocked, and the other end is connected to a high-frequency pulse gas source, and the expansion and contraction of the vibration column 342 is utilized to realize vibration while injection molding, so as to vibrate out the bubbles in the injection liquid and make the injection liquid dense.

[0066] After the injection of the molding liquid is completed, the injection port is blocked and an appropriate air pressure is maintained in the cavity 32. The pressure of the vibration column 342 is used to achieve stable pressure maintenance, reduce the shrinkage caused by the cooling of the molding liquid, and improve the molding quality of the magnet.

Claims

1. A rotor assembly for a canned motor pump, comprising a rotor core (5) formed by pressing a stamped sheet, a metal shaft (3) passing through the middle of the rotor core, and a die-cast aluminum cage (2), characterized in that: Along the radial direction of the rotor core (5), the rotor core (5) is provided with four layers of magnet slots, a magnetic channel is formed between two magnet slots, an injection-molded ferrite (4) formed by injection molding of ferrite is provided in the magnet slots, and an injection molding port communicating with the magnet slots is left at the top of the rotor core (5); A plurality of groups of conductor slots are provided on the rotor core (5) along the circumference of the rotor core (5), round copper bars (6) are provided in the conductor slots, and a filling slot is provided on a side of some of the conductor slots facing the magnet. During die casting, aluminum liquid can flow from one end of the rotor core (5) to the other end along the filling slots to form a cast aluminum cage (2). The conductor bars of the cast aluminum cage (2) are composed of the round copper bars (6) and the cast aluminum bars in the filling slots. The rotor core (5) is composed of a main punching sheet (51), a rotor middle section punching sheet (52), and an end section punching sheet (53). The rotor core (5) is composed of a main punching sheet (51), the end face punching sheet (53) constitutes the end of the rotor core (5), the rotor middle section punching sheet (52) constitutes the middle section of the rotor core (5), and the other areas are composed of main punching sheets (51), the magnet slots are provided on the main punching sheets (51) and the rotor middle section punching sheets (52), the rotor middle section punching sheets (52) are provided with injection molding flow channel slots (521) connecting the middle three layers of magnet slots, and the middle parts of the end face punching sheets (53) are provided with axially connected injection molding feed slots (531).

2. A rotor assembly for a canned motor pump according to claim 1, characterized in that: An open slot is set every 1-3 conductor slots, and the remaining conductor slots are closed slots.

3. A rotor assembly for a canned motor pump according to claim 1, characterized in that: The metal shaft (3) comprises a shaft tube (31), a cavity (32) is provided at the axis of the shaft tube (31), a buffer absorber (33) and a vibrator (34) are sleeved on the outer wall of the shaft tube (31), the vibrator (34) comprises a movable groove (341), the outer wall of the shaft tube (31) is provided with two groups of movable grooves (341) facing each other, the movable grooves (341) are movably connected to a vibrating column (342), the movable grooves (341) are connected to a pulse air source through the cavity (32), the pulse air source intermittently drives the vibrating column (342) to extend, an elastic pull rope (343) capable of pulling the vibrating column (342) to contract is provided between the two vibrating columns (342), and during the interval of air supply, the vibrating column (342) contracts under the elastic force of the elastic pull rope (343).

4. A rotor assembly for a canned motor pump according to claim 3, characterized in that: The insertion depth of the vibration column (342) is aligned with the injection runner grooves (521) on both sides, a capsule (344) is provided between the vibration column (342) and the bottom of the movable groove (341), and two ends of the capsule (344) are respectively fixedly connected to the groove bottom of the movable groove (341) and the bottom of the vibration column (342).

5. A rotor assembly for a canned motor pump according to claim 4, characterized in that: A limiting groove (346) is provided near the mouth of the movable groove (341), and a resilient telescopic limiting block (345) is provided at the bottom of the outer side wall of the vibration column (342); when the telescopic limiting block (345) slides into the limiting groove (346), the telescopic limiting block (345) can be restricted from sliding out.

6. A rotor assembly for a canned motor pump according to claim 5, characterized in that: An absorption groove (331) is provided on one side of the buffer absorber (33), an elastic bag (332) is provided on the absorption groove (331), and an elastic body is filled in the absorption groove (331).

7. A method for manufacturing a rotor assembly for a canned motor pump, used for manufacturing a rotor assembly for a canned motor pump as claimed in claim 6, characterized in that: Includes steps: S1: Silicon steel sheets are punched at high speed to obtain a rotor core (5), wherein end segment punching sheets (53), middle segment punching sheets (52) and main punching sheets (51) are placed in a set order and quantity; S2: The rotor core (5) is pressed into the round copper bar (6) to obtain a rotor assembly 1; S3: Rotor component 1 is die-cast in an aluminum casting mold to obtain rotor component 2; S4: turning the outer diameter of rotor component 2 to obtain rotor component 3; S5: inserting the metal shaft (3) into the rotor component three, and using ferrite material for injection molding to obtain the rotor component four; S6: Rotor assembly 4 is pressed into the stainless steel shielding sleeve (7) to obtain rotor assembly 5; S7: Both ends of the rotor assembly 5 are pressed into the stainless steel cover plate (1) to obtain the rotor assembly 6; S8: welding the upper and lower ends of the rotor assembly 6 to obtain the rotor assembly 7; S9: The rotor assembly 7 is magnetized as a whole to obtain the rotor assembly of the present invention.

8. The method for manufacturing a rotor assembly for a canned motor pump according to claim 7, characterized in that: In step S5, during injection molding, one end of the cavity (32) is blocked and the other end is connected to a high-frequency pulse gas source, and vibration is achieved while injection molding by utilizing the expansion and contraction of the vibration column (342), so as to vibrate out bubbles in the injection liquid and make the injection liquid dense.

9. The method for manufacturing a rotor assembly for a canned motor pump according to claim 8, characterized in that: When the injection of the molding liquid is completed, the injection port is blocked, and appropriate air pressure is maintained in the cavity (32), and stable pressure maintenance is achieved through the pressure of the vibration column (342).

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