Fluid pump and rotor thereof

Abstract

The application discloses a rotor for a fluid pump, comprising at least one bearing, a magnetic conducting ring located radially outside the at least one bearing, a rotor support which is injection molded and integrally fixed with the at least one bearing and the magnetic conducting ring, a plurality of permanent magnets located at the outer periphery of the magnetic conducting ring, and a protective shell sleeved at the outer periphery of the plurality of permanent magnets, wherein the rotor support comprises a cylindrical main body and a plurality of retaining portions which are circumferentially spaced around the main body, the main body is injection molded between the at least one bearing and the magnetic conducting ring, the magnetic conducting ring is radially located between the main body and the plurality of retaining portions, the plurality of permanent magnets are respectively retained in the space between adjacent retaining portions, and the thickness of the protective shell is less than 0.8 mm, so that the air gap between the stator and the rotor is effectively reduced, and the motor power density is improved.

Description

Technical Field

[0001] This application relates to fluid pumps, and more particularly to a rotor for a fluid pump. Background Technology

[0002] Fluid pumps are typically connected in series in pipelines for transporting fluids such as water and coolants. Generally, a fluid pump consists of an impeller and a motor that drives the impeller to rotate, with the motor rotor connected to the impeller for synchronous rotation.

[0003] In existing fluid pumps, the motor rotor typically includes a cylindrical plastic shell that is molded over the outer periphery of several permanent magnets on the rotor. In this type of motor rotor, the molding process of the plastic shell results in a relatively large thickness, leading to a larger air gap between the stator and rotor, and a lower power density. Utility Model Content

[0004] In view of this, the purpose of this application is to provide a fluid pump with high motor power density and its rotor.

[0005] On one hand, this application provides a rotor for a fluid pump, including at least one bearing, a magnetic ring located radially outside the at least one bearing, a rotor support molded and integrally fixed with the at least one bearing and the magnetic ring, a plurality of permanent magnets located on the outer periphery of the magnetic ring, and a protective shell sleeved on the outer periphery of the plurality of permanent magnets. The rotor support includes a cylindrical main body and a plurality of retaining parts arranged circumferentially around the main body. The main body is injection molded between the at least one bearing and the magnetic ring. The magnetic ring is located radially between the main body and the plurality of retaining parts. The plurality of permanent magnets are respectively retained in the space between adjacent retaining parts. The thickness of the protective shell is less than 0.8 mm.

[0006] The rotor used for the fluid pump may exhibit one or more of the following features, either individually or in combination.

[0007] Preferably, the at least one bearing comprises two bearings spaced axially apart, and a bearing support located between the two bearings.

[0008] Preferably, the rotor further includes an impeller, which is separately formed and fixed to one axial end of the rotor support.

[0009] Preferably, the rotor further includes an impeller, and the rotor support further includes a base plate of the impeller, the base plate of the impeller being located at one axial end of the main body of the rotor support.

[0010] Preferably, the rotor support further includes a plurality of blades integrally injection molded onto the substrate of the impeller.

[0011] Preferably, the impeller includes a cover plate, on which a plurality of blades are integrally formed, and the cover plate or the plurality of blades are fixed to the base plate of the impeller.

[0012] Preferably, the rotor further includes an impeller, and the main body of the rotor support convexes radially outward at one end away from the impeller to form a flange. At least two magnetic ring positioning structures are formed on the flange. The at least two magnetic ring positioning structures are positioning grooves or positioning holes that penetrate the flange in the axial direction, and are used to position the magnetic rings through the positioning grooves or positioning holes when the rotor support is injection molded.

[0013] Preferably, the rotor further includes an impeller, and the main body of the rotor support axially away from the impeller at one end protrudes radially to form a flange, the flange extending at least partially beyond the protective housing in the axial direction so that the flange provides a magnetization positioning mark for magnetizing the plurality of permanent magnets.

[0014] Preferably, the rotor further includes an impeller, and the main body of the rotor support extends radially outward from one end near the impeller to form an annular extension, the annular extension being integrally connected to one axial end of the plurality of retaining portions.

[0015] Preferably, the main body of the rotor support has a flange that protrudes radially outward at one end away from the impeller, the outer diameter of the flange is less than or equal to the outer diameter of the magnetic ring, the magnetic ring is axially located between the flange and the annular extension, and the other axial end of the plurality of retaining portions is integrally connected to the flange.

[0016] Preferably, the flange is an annular flange extending in the circumferential direction.

[0017] Preferably, a cylindrical axial connecting portion is connected between the annular extension and the base plate of the impeller, wherein the outer diameter of the axial connecting portion is larger than the outer diameter of the main body and smaller than the outer diameter of the annular extension.

[0018] Preferably, the protective shell includes a cylinder and two annular rims extending radially inward from both ends of the cylinder, the cylinder surrounding the plurality of permanent magnets, wherein one of the annular rims abuts axially with the annular extension of the rotor support, and the other annular rim abuts axially with the plurality of permanent magnets.

[0019] Preferably, the magnetic ring is a cylindrical structure formed by rolling a magnetic sheet, and the end of the cylindrical structure has an axial gap. The main body of the rotor support has an axial protrusion at the position corresponding to the axial gap.

[0020] Preferably, each holding portion includes a partition and wings extending radially outward from the outer end of the partition to both sides in the circumferential direction. The partition is located between adjacent permanent magnets. The wings of the plurality of holding portions cover part of the outer circumferential surface of the plurality of permanent magnets, thereby initially positioning the plurality of permanent magnets on the rotor support, which facilitates the assembly of the protective shell.

[0021] Preferably, the plurality of permanent magnets are ferrite permanent magnets, and the protective shell is a metal protective shell.

[0022] On the other hand, this application provides a fluid pump, including a stator and the aforementioned rotor for a fluid pump, wherein a motor shaft is fixedly disposed in the fluid pump, and the at least one bearing of the rotor is rotatably sleeved on the motor shaft.

[0023] Compared with the prior art, in the fluid pump and its rotor provided in this application, the rotor support is injection molded and integrally fixed with bearings and magnetic rings. The rotor support also has several holding parts for holding permanent magnets. The permanent magnets are fixed to the outer periphery of the magnetic rings. The protective shell is separately molded and surrounds the permanent magnets. The thickness of the protective shell can be reduced to less than 0.8 mm, thereby effectively reducing the air gap between the stator and rotor and improving the power density of the motor. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a fluid pump according to an embodiment of this application.

[0025] Figure 2 for Figure 1 The image shows an axial sectional view of the fluid pump.

[0026] Figure 3 for Figure 1 The exploded view of the fluid pump is shown.

[0027] Figure 4 for Figure 3 The diagram shows the structure of the rotor of the fluid pump.

[0028] Figure 5 for Figure 4 A further exploded view of the rotor shown.

[0029] Figure 6 for Figure 5 Another perspective view.

[0030] Figure 7 for Figure 6 Further exploded views of the rotor support, bearing assembly, and magnetic ring of the rotor shown.

[0031] Figure 8 for Figure 4 The rotor shown is a cross-sectional view.

[0032] Figure 9 for Figure 4 Another sectional view of the rotor shown. Detailed Implementation

[0033] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. One or more embodiments of this application are exemplarily shown in the drawings to provide a more accurate and thorough understanding of the technical solutions disclosed herein. However, it should be understood that this application can be implemented in many different forms and is not limited to the embodiments described below.

[0034] In the accompanying drawings of this application, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0035] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously.

[0036] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0037] This application provides a fluid pump for driving the flow of fluids, such as water and coolant, in a pipeline. The fluid pump can be used as a cooling pump for a motor vehicle. Figure 1-3The illustration shows a specific embodiment of the fluid pump of this application. The fluid pump 100 includes a pump casing 10, an impeller 20 disposed in the pump casing 10, and a motor 30 that drives the impeller 20 to rotate within the pump casing 10. The motor 30 includes a motor stator 32 and a motor rotor 34 rotatable relative to the motor stator 32. The motor rotor 34 is connected to the impeller 20 and rotates together with it, and is considered as the rotor of the fluid pump 100.

[0038] Please also refer to Figure 4 The impeller 20 has an overall disc-shaped structure and is rotatably disposed in the center of the pump casing 10. Correspondingly, the pump casing 10 is provided with an inlet 12 and an outlet 14 to connect its internal space with external pipelines, forming a fluid flow path.

[0039] like Figure 5 As shown, the impeller 20 includes a base plate 22 and a cover plate 24 arranged at relatively intervals, and a plurality of blades 26 disposed between the base plate 22 and the cover plate 24. The blades 26 and the base plate 22 are integrally formed by injection molding, and the cover plate 24, after being formed separately, is fixedly connected to the blades 26 by means of snap-fitting, welding, or bonding. In other embodiments, the cover plate 24 may also be fixedly connected to the base plate 22. In other embodiments, the blades 26 may also be integrally formed on the cover plate 24, and either the blades 26 or the cover plate 24 may be fixed to the base plate 22.

[0040] like Figure 2 and Figure 3 As shown, the motor 30 is preferably an internal rotor motor, with its motor rotor 34 rotatably disposed at the center of the motor stator 32. A motor shaft 40 is fixedly disposed in the fluid pump 100, and the motor rotor 34 and impeller 20 are rotatably sleeved on the motor shaft 40. When the motor 30 starts, the motor rotor 34 and impeller 20 rotate around the motor shaft 40.

[0041] like Figure 5-9 As shown, the rotor of the fluid pump includes a bearing assembly 342, a magnetic ring 343 located radially outside the bearing assembly 342, a rotor support 341 injection-molded and integrally fixed with the bearing assembly 342 and the magnetic ring 343, a plurality of permanent magnets 345 located on the outer periphery of the magnetic ring 343, and a protective shell 346 sleeved on the outer periphery of the plurality of permanent magnets 345. The motor shaft 40 passes through the bearing assembly 342.

[0042] The rotor support 341 is injection molded and includes a cylindrical main body 3411, a plurality of retaining portions 3412 surrounding the main body 3411, and a base plate 22 of the impeller 20 located at one axial end of the main body 3411. The main body 3411 is injection molded between the bearing assembly 342 and the magnetic guide ring 343, which is radially located between the main body 3411 and the plurality of retaining portions 3412. The plurality of retaining portions 3412 are distributed approximately evenly in the circumferential direction, and a space is formed between two adjacent retaining portions 3412 to accommodate permanent magnets 345.

[0043] Preferably, each retaining portion 3412 has a generally T-shaped cross-section, including a partition portion 3412a and wing portions 3412b extending radially outward from the outer end of the partition portion 3412a to both circumferential sides. The partition portion 3412a is located between adjacent permanent magnets 345. The wing portions 3412b cover part of the outer circumferential surface of the adjacent permanent magnet 345, thereby initially positioning the permanent magnet 345 on the rotor support 341, facilitating the assembly of the protective shell 346.

[0044] Preferably, the main body 3411 extends radially outward to form an annular extension 3415, which is axially located between the base plate 22 of the impeller 20 and the other axial end of the rotor, and is axially closer to the base plate 22 of the impeller 20. The annular extension 3415 is integrally connected to one axial end of a plurality of retaining portions 3412. More preferably, the outer diameter of the annular extension 3415 of the rotor support 341 is equivalent to the outer diameter of the outer circumferential surface of the cylinder on which the plurality of permanent magnets 345 are located, thereby axially limiting the permanent magnets 345 when assembling them.

[0045] Preferably, a cylindrical axial connecting portion 3414 is integrally connected between the annular extension 3415 and the base plate 22 of the impeller 20. More preferably, the outer diameter of the axial connecting portion 3414 is larger than the outer diameter of the main body 3411 and smaller than the outer diameter of the annular extension 3415.

[0046] Preferably, at the end of the main body 3411 that is axially away from the impeller 20, i.e., at the other axial end of the main body 3411, an annular flange 3416 is formed radially outward. The outer diameter of the annular flange 3416 is less than or equal to the outer diameter of the magnetic ring 343. The magnetic ring 343 is axially located between the annular flange 3416 and the annular extension 3415. The other axial ends of the plurality of retaining portions 3412 are integrally connected to the annular flange 3416.

[0047] Preferably, at least two magnetic ring positioning structures 3418 are formed on the annular flange 3416. These at least two magnetic ring positioning structures 3418 are positioning grooves or positioning holes that penetrate the annular flange 3416 axially, used to position the magnetic rings 343 through the positioning grooves or positioning holes during the injection molding of the rotor support 341. In the illustrated embodiment, a plurality of magnetic ring positioning grooves are formed inwardly on the outer peripheral wall of the annular flange 3416.

[0048] Preferably, after the protective shell 346 is assembled, the annular flange 3416 extends outward relative to the protective shell 346 by a certain length in the axial direction, so that the annular flange 3416 provides a magnetization positioning mark for magnetizing a plurality of permanent magnets 345.

[0049] In this embodiment, at least one magnetization positioning mark 3417 is formed on the axial end face of the annular flange 3416 for magnetizing the permanent magnet 345 after the protective shell 346 is assembled. Preferably, the annular flange 3416 has a plurality of magnetization positioning marks 3417, which are positioning grooves or positioning protrusions, preferably positioning holes that penetrate the annular flange 3416 axially, so as to further position the magnetic ring 343 when the rotor support 341 is injection molded. In the illustrated embodiment, the magnetization positioning marks 3417 and the magnetic ring positioning structures 3418 are alternately distributed in the circumferential direction. In other embodiments, at least two magnetic ring positioning structures 3418 of the annular flange 3416 can simultaneously serve as magnetization positioning marks, thus eliminating the need to form at least one magnetization positioning mark 3417 separately.

[0050] The bearing assembly 342 is integrally fixed in the main body 3411 of the rotor support 341, and includes a bearing support 3422 and a first bearing 3424 and a second bearing 3426 located at both ends of the bearing support 3422. The first bearing 3424 and the second bearing 3426 are coaxially spaced apart, with the first bearing 3424 located at the top end of the main body 3411 and the second bearing 3426 located at the bottom end of the main body 3411, providing effective support for both ends of the motor shaft 40. In other embodiments, the bearing assembly 342 can also be replaced by a bearing with a longer axial length to provide effective support for the motor shaft 40.

[0051] The first bearing 3424, the second bearing 3426, and the bearing support 3422 are placed together in the mold and integrally fixed in the rotor bracket 341 during injection molding. Preferably, the inner diameter of the bearing support 3422 is larger than the inner diameters of the first bearing 3424 and the second bearing 3426, so that after assembly with the motor shaft 40, the bearing support 3422 and the motor shaft 40 have a clearance fit.

[0052] Preferably, the outer peripheral walls of the first bearing 3424 and the second bearing 3426 are formed with protrusions 3428. When forming the rotor support 341, the main body 3411 of the rotor support 341 forms recesses 3419 at positions corresponding to the protrusions 3428. In this way, the first bearing 3424, the second bearing 3426 and the main body 3411 fit together, further improving the stability of their connection.

[0053] In other embodiments, recesses may be formed on the outer peripheral walls of the bearings 3424 and 3426, and a protrusion may be formed on the main body 3411 of the rotor support 341 at the corresponding recess position when the rotor support 341 is formed. Similarly, the stability of the connection between the bearings 3424 and 3426 and the rotor support 341 is improved by the concave-convex fit.

[0054] The magnetic ring 343 is cylindrical in shape and has high magnetic permeability. In this embodiment, the magnetic ring 343 is a cylindrical structure rolled from a magnetic sheet. The end of the cylindrical structure has an axial gap 3430. The main body 3411 of the rotor support 341 has an axial protrusion 3413 at the position corresponding to the axial gap to improve the stability of the connection between the two. In other embodiments, the magnetic ring 343 can also be formed by stacking several annular magnetic sheets, such as motor rotor laminations made of silicon steel sheets. Several grooves can be formed on the outer periphery of the motor rotor laminations. The grooves are spaced apart in the circumferential direction. When the rotor support 341 is injection molded, several retaining parts 3412 of the rotor support 341 are embedded in the grooves to improve the stability of the connection between the two. In this application, the magnetic ring 343 and the bearing assembly 342 are placed together in the mold, and the rotor support 341 is injection molded in one step to fix the magnetic ring 343 and the bearing assembly 342.

[0055] In the above embodiments, the rotor support 341 includes the base plate 22 of the impeller 20. In other embodiments, the motor rotor support 341 and the impeller 20 can be formed separately and then fixed together by means of heat fusion or the like. In this case, the rotor support 341 no longer includes the base plate 22 of the impeller 20; the base plate 22 is formed separately and then fixed to one axial end of the rotor support 341 by means of heat fusion or the like.

[0056] In the above embodiments, the cylindrical axial connecting portion 3414 is integrally formed between the annular extension 3415 and the base plate 22 of the impeller 20. In other embodiments, when the rotor support 341 and the impeller 20 are formed separately, the axial connecting portion 3414 can be integrally formed on one axial end of the annular extension 3415 and then connected to the base plate 22 of the impeller 20, or integrally formed on the base plate 22 of the impeller 20 and then connected to one axial end of the annular extension 3415, or formed separately and then connected to both the annular extension 3415 and the base plate 22.

[0057] The method for manufacturing the rotor of the fluid pump 100 of this application specifically includes the following steps:

[0058] Step 1: Provide at least one bearing and a magnetic ring 343 and place them in a mold, wherein the magnetic ring 343 encircles the at least one bearing and is radially spaced from it;

[0059] Step 2: Injection molding rotor support 341. The rotor support 341 includes a cylindrical main body 3411, a plurality of retaining parts 3412 arranged around the main body 3411 and spaced apart in the circumferential direction, and a base plate 22 of the impeller 20 located at one axial end of the main body 3411. The main body 3411 is injection molded between the at least one bearing and the magnetic ring 343. The magnetic ring 343 is located radially between the main body 3411 and the plurality of retaining parts 3412.

[0060] Step 3: Provide a plurality of permanent magnets 345 and assemble the plurality of permanent magnets 345 into the space between adjacent holding portions 3412 of the rotor support 341, wherein the plurality of permanent magnets 345 are located on the outer periphery of the magnetic guide ring 343; and

[0061] Step four: Provide a protective shell 346 and attach the protective shell 346 to the outside of the plurality of permanent magnets 345.

[0062] Preferably, the at least one bearing includes a bearing support 3422 and a first bearing 3424 and a second bearing 3426 located at both ends of the bearing support 3422. Preferably, in step two above, a plurality of blades 26 are further injection molded on the impeller substrate 22.

[0063] In step two above, a base plate 22 for the impeller 20 is formed at one axial end of the rotor support 341. In other embodiments, the motor rotor support 341 and the impeller 20 can be formed separately and then fixed together by means of heat fusion or the like. In this case, in step two above, the rotor support 341 no longer includes the base plate 22 for the impeller 20. The base plate 22 is formed separately and then fixed to one axial end of the rotor support 341 by means of heat fusion or the like.

[0064] Preferably, in step two above, the main body 3411 extends radially outward to form an annular extension 3415. The annular extension 3415 is located axially between the base plate 22 of the impeller 20 and the other axial end of the rotor, and is axially closer to the base plate 22 of the impeller 20. The annular extension 3415 is integrally connected to one axial end of a plurality of retaining portions 3412. More preferably, the outer diameter of the annular extension 3415 of the rotor support 341 is equivalent to the outer diameter of the outer circumferential surface of the cylinder containing the plurality of permanent magnets 345, thereby axially limiting the permanent magnets 345 when assembling them. Preferably, a cylindrical axial connecting portion 3414 is integrally connected between the annular extension 3415 and the base plate 22 of the impeller 20. More preferably, the outer diameter of the axial connecting portion 3414 is larger than the outer diameter of the main body 3411 and smaller than the outer diameter of the annular extension 3415.

[0065] Preferably, in step two above, the end of the main body 3411 that is axially away from the impeller 20, i.e., the other axial end of the main body 3411, forms an annular flange 3416 that protrudes radially outward. The outer diameter of the annular flange 3416 is less than or equal to the outer diameter of the magnetic ring 343. The magnetic ring 343 is axially located between the annular flange 3416 and the annular extension 3415. The axial ends of the plurality of retaining portions 3412 are integrally connected to the annular flange 3416 and the annular extension 3415, respectively.

[0066] Preferably, in step two above, at least two magnetic ring positioning structures 3418 are formed on the annular flange 3416 for positioning the magnetic ring 343 during injection molding of the rotor support 341.

[0067] Preferably, in step four above, the annular flange 3416 extends at least partially beyond the protective housing 346 in the axial direction so that the annular flange 3416 provides a magnetization positioning mark for magnetizing the plurality of permanent magnets 345.

[0068] In other embodiments, several permanent magnets may be further placed in the mold in step one above, so that several holding parts in step two above are formed between adjacent permanent magnets, while step three above is omitted.

[0069] Compared to existing technologies, the protective shell 346 of the rotor of the fluid pump 100 of this application is separately formed and then rings around the plurality of permanent magnets 345. Compared to the rotor shell formed by overmolding in existing technologies, the thickness of the protective shell of this application can be controlled to be smaller due to separate molding, less than 0.8 mm, which effectively reduces the air gap between the stator and rotor of the motor 30 and improves the power density of the motor.

[0070] Preferably, the permanent magnet 345 in this application is a low-cost ferrite permanent magnet. The protective shell 346 is made of a non-magnetic or low-magnetic-permeability material, preferably a metal material. Metal materials have high strength and can be thinner, further reducing the air gap of the motor 30. Preferably, the protective shell 346 includes a cylinder 3462 and a first annular flange 3464 and a second annular flange 3466 extending radially inward from both ends of the cylinder 3462. The cylinder 3462 encircles the plurality of permanent magnets 345. The first annular flange 3464 is located outside the annular extension 3415 of the rotor support 341, and the two are axially abutted and positioned. The second annular flange 3466 is located at one end of the plurality of permanent magnets 345 and is axially abutted and positioned with the permanent magnet 345. The inner diameter of the second annular flange 3466 is not less than the outer diameter of the annular flange 3416. After assembly, the annular flange 3416 extends outward from the center of the second annular flange 3466.

[0071] like Figure 2 and Figure 3 As shown, the fluid pump 100 is further provided with a sleeve 50, which divides the internal space of the fluid pump 100 into a first space 16 and a second space 18. The first space 16 is used to install the impeller 20 and the motor rotor 34, and the second space 18 is used to install the motor stator 32. In this way, the internal space of the fluid pump 100 is separated into wet and dry areas by the sleeve 50, and the fluid flows only in the first space 16, effectively preventing the fluid from entering the second space 18 and affecting electrical safety, so that the fluid pump 100 can operate safely.

[0072] Specifically, the sleeve 50 is a cylindrical structure with an open top and a closed bottom, and the pump housing 10 covers the open end of the sleeve 50. A first bearing seat 52 is formed at the center of the bottom of the sleeve 50, and a second bearing seat 11 can be formed at the center of the pump housing 10. The bottom end of the motor shaft 40 is fixed in the first bearing seat 52, and the top end is accommodated in the second bearing seat 11.

[0073] It should be noted that the above embodiments only illustrate preferred embodiments of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting this application. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of this application, such as combining different features in various embodiments, and these should all fall within the protection scope of this application.

Claims

1. A rotor for a fluid pump, characterized by, The device includes at least one bearing, a magnetic ring located radially outside the at least one bearing, a rotor support molded and integrally fixed to the at least one bearing and the magnetic ring, a plurality of permanent magnets located on the outer periphery of the magnetic ring, and a protective shell sleeved on the outer periphery of the plurality of permanent magnets. The rotor support includes a cylindrical main body and a plurality of retaining parts arranged circumferentially around the main body. The main body is injection molded between the at least one bearing and the magnetic ring. The magnetic ring is located radially between the main body and the plurality of retaining parts. The plurality of permanent magnets are respectively retained in the space between adjacent retaining parts. The thickness of the protective shell is less than 0.8 mm.

2. The rotor for a fluid pump of claim 1, wherein, The at least one bearing includes two bearings spaced axially apart, and a bearing support located between the two bearings.

3. The rotor for a fluid pump of claim 1, wherein, The rotor further includes an impeller, which is separately formed and fixed to one axial end of the rotor support.

4. The rotor for a fluid pump of claim 1, wherein, The rotor further includes an impeller, and the rotor support further includes a base plate of the impeller, the base plate of the impeller being located at one axial end of the main body of the rotor support.

5. The rotor for a fluid pump of claim 4, wherein, The rotor support further includes a plurality of blades integrally injection molded onto the base plate of the impeller.

6. The rotor for a fluid pump of claim 4, wherein, The impeller includes a cover plate, on which a plurality of blades are integrally formed, and the cover plate or the plurality of blades are fixed to the base plate of the impeller.

7. The rotor for a fluid pump of claim 1, wherein, The rotor further includes an impeller, and the main body of the rotor support convexes radially outward at one end away from the impeller to form a flange. At least two magnetic ring positioning structures are formed on the flange. The at least two magnetic ring positioning structures are positioning grooves or positioning holes that penetrate the flange in the axial direction, and are used to position the magnetic rings through the positioning grooves or positioning holes when the rotor support is injection molded.

8. The rotor for a fluid pump of claim 1, wherein, The rotor further includes an impeller, and the main body of the rotor support axially protrudes radially outward at one end away from the impeller to form a flange, which at least partially extends axially beyond the protective housing so that the flange provides a magnetization positioning mark for magnetizing the plurality of permanent magnets.

9. The rotor for a fluid pump of claim 1, wherein, The rotor further includes an impeller, and the main body of the rotor support extends radially outward to form an annular extension. The annular extension is located axially between the impeller and the end of the rotor away from the impeller, and is axially closer to the impeller. The annular extension is integrally connected to one axial end of the plurality of retaining portions.

10. The rotor for a fluid pump of claim 9, wherein, The main body of the rotor support has a flange that protrudes radially outward at one end away from the impeller. The outer diameter of the flange is less than or equal to the outer diameter of the magnetic ring. The magnetic ring is located axially between the flange and the annular extension. The other axial ends of the plurality of retaining portions are integrally connected to the flange.

11. A rotor for a fluid pump as claimed in any of claims 7 to 8 and 10, wherein, The flange is an annular flange extending in the circumferential direction.

12. The rotor for a fluid pump as claimed in claim 9, characterized in that, A cylindrical axial connecting portion is connected between the annular extension and the base plate of the impeller. The outer diameter of the axial connecting portion is larger than the outer diameter of the main body and smaller than the outer diameter of the annular extension.

13. The rotor for a fluid pump of claim 9, wherein, The protective shell includes a cylinder and two annular rims extending radially inward from both ends of the cylinder. The cylinder surrounds the plurality of permanent magnets, wherein one of the annular rims abuts axially with the annular extension of the rotor support, and the other annular rim abuts axially with the plurality of permanent magnets.

14. The rotor for a fluid pump of claim 1, wherein, The magnetic ring is a cylindrical structure formed by rolling a magnetic sheet. The end of the cylindrical structure has an axial gap. The main body of the rotor support has an axial protrusion at the position corresponding to the axial gap.

15. The rotor for a fluid pump of claim 1, wherein, Each retaining portion includes a partition and wings extending radially outward from the outer end of the partition to both sides in the circumferential direction. The partition is located between adjacent permanent magnets. The wings of the plurality of retaining portions cover part of the outer circumferential surface of the plurality of permanent magnets, thereby initially positioning the plurality of permanent magnets on the rotor support, which facilitates the assembly of the protective shell.

16. The rotor for a fluid pump of claim 1, wherein, The permanent magnets are ferrite permanent magnets, and the protective shell is a metal protective shell.

17. A fluid pump, characterized by The pump includes a stator and a rotor for a fluid pump as described in any one of claims 1-16, wherein a motor shaft is fixedly disposed in the fluid pump, and the at least one bearing of the rotor is rotatably mounted on the motor shaft.

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