Fluid pump

Abstract

A fluid pump, comprising a pump housing (10), an impeller (20) arranged in the pump housing (10), and a motor (30) configured to drive the impeller (20) to rotate in the pump housing (10). The motor (30) comprises a stator (32) and a rotor (34); the rotor (34) is fixedly connected to the impeller (20) by means of a rotating shaft (40); a sleeve (50) is provided in the pump housing (10); the sleeve (50) divides the internal space of the pump housing (10) into a first space (16) and a second space (18); the rotor (34), the rotating shaft (40), and the impeller (20) are movably arranged in the first space (16); the stator (32) is fixedly arranged in the second space (18); a first bearing assembly (42) and a second bearing assembly (44) are respectively provided on two ends of the rotating shaft (40); and the second bearing assembly (44) is connected to the end of the sleeve (50) distant from the impeller (20) and is fixedly connected to the sleeve (50), so that the two ends of the rotating shaft (40) can be effectively supported to avoid deflection, thereby improving the operation stability and safety of the fluid pump.

Description

Fluid pump TECHNICAL FIELD

[0001] The present application relates to the technical field of pumps, in particular to a fluid pump. BACKGROUND

[0002] Pumps are usually connected in series in a pipeline for the delivery of fluids, such as water, coolant, fuel gas, etc., such as in the thermal management system of an electric vehicle charger, for the delivery of coolant to cool the battery or cable, etc.

[0003] In the existing structure, the pump generally comprises a pump shell, an impeller arranged in the pump shell, and a motor for driving the impeller to rotate in the pump shell. The motor comprises a stator and a rotor rotatable relative to the stator, the rotor is connected to the impeller to drive the impeller to rotate. In order to avoid the influence of fluid on the electrical safety of the motor, the stator and the rotor are separated by a sleeve, the stator is sleeved on the outside of the sleeve, the inside of the sleeve is fixed with a shaft, and the rotor and the impeller are rotatably sleeved on the shaft.

[0004] Due to the cantilever beam structure of the shaft, the impeller may produce a certain degree of deflection during rotation due to the uneven stress in the circumferential direction, especially when the fluid, such as coolant, contains a high proportion of air. This not only affects the stability of the impeller rotation, but also may cause damage to the parts due to stress at the fixed end of the shaft, affecting the safety of use. SUMMARY

[0005] Therefore, it is necessary to provide a fluid pump that can effectively improve its running stability and safety.

[0006] A fluid pump comprises a pump shell, an impeller arranged in the pump shell, and a motor for driving the impeller to rotate in the pump shell. The motor comprises a stator and a rotor, the rotor is fixedly connected to the impeller through a shaft, a sleeve is arranged in the pump shell, the sleeve separates the internal space of the pump shell into a first space and a second space, the rotor, the shaft and the impeller are movably arranged in the first space, the stator is fixedly arranged in the second space, the two ends of the shaft are respectively provided with a first bearing assembly and a second bearing assembly, and the second bearing assembly is located at the end of the sleeve away from the impeller and is fixedly connected to the sleeve.

[0007] Compared with the prior art, the fluid pump provided by the present application separates the motor stator, the motor rotor and the impeller by the sleeve to avoid the influence of fluid erosion on the electrical safety of the stator. The rotor is fixedly connected to the impeller through the shaft, and the two ends of the shaft are respectively provided with a first bearing assembly and a second bearing assembly, so that the two ends of the shaft can be effectively supported to avoid deflection. The impeller can rotate smoothly even if it is subjected to uneven stress in the circumferential direction, thereby improving the stability and safety of the fluid pump. BRIEF DESCRIPTION OF DRAWINGS

[0008] Fig. 1 is a schematic view of an embodiment of a fluid pump according to the present application.

[0009] Fig. 2 is an exploded view of the fluid pump of Fig. 1.

[0010] Fig. 3 is an axial sectional view of the fluid pump of Fig. 1.

[0011] Fig. 4 is an assembly view of the motor rotor, impeller, and sleeve of the fluid pump of Fig. 2.

[0012] Fig. 5 is a radial sectional view of Fig. 4.

[0013] Fig. 6 is an exploded view of Fig. 4.

[0014] Fig. 7 is another angle view of Fig. 6.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 100 fluid pump;

[0017] 10 pump housing; 10a pump housing body; 10b pump housing cover; 12 inlet; 14 outlet; 16 first space; 161 first sub-space; 163 second sub-space; 18 second space;

[0018] 20 impeller; 22 bottom plate; 24 cover plate; 26 blade; 28 first shaft hole;

[0019] 30 motor; 32 stator; 321 stator housing; 323 magnetic core; 325 coil; 327 circuit board; 34 rotor; 341 iron core; 343 permanent magnet; 345 rotor housing; 347 second shaft hole;

[0020] 40 shaft; 41 flow passage; 42 first bearing assembly; 44 second bearing assembly;

[0021] 45 first bearing; 46 first bearing seat; 461 recess; 463 through hole;

[0022] 47 second bearing; 48 second bearing seat; 481 inner ring; 482 assembly hole; 483 outer ring; 485 rib; 487 passage; 489 positioning groove; 49 fixing member; 491 first ring portion; 493 second ring portion; 495 positioning portion;

[0023] 50 sleeve; 52 open end; 54 closed end; 56 first flange; 57 protrusion; 58 folded edge; 59 second flange. Embodiments of the present application

[0024] For the purpose of facilitating the understanding of the present application, the present application will be described in greater detail below with reference to the accompanying drawings. The accompanying drawings show one or more embodiments of the present application in order to make the understanding of the technical solutions disclosed by the present application more accurate and thorough. However, it should be understood that the present application can be implemented in many different forms and is not limited to the embodiments described below.

[0025] The same or similar reference numerals in the accompanying drawings correspond to the same or similar components; in the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms “upper”, “lower”, “left”, “right” and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are used only for exemplary illustration and cannot be understood as a limitation on the present application, for those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0026] In addition, if the present application has a description of “first”, “second” and the like in the embodiments, the description of “first”, “second” and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features indicated or implying the number of technical features indicated. Therefore, the features limited by “first”, “second” can explicitly or implicitly include at least one of the features. In addition, “and / or” or “and / or” appearing throughout the text means that the three parallel schemes include A scheme, or B scheme, or A and B schemes are satisfied at the same time.

[0027] In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection claimed by the present application.

[0028] The present application provides a kind of fluid pump, for driving fluid, such as water, coolant etc. in pipeline flow.The specific embodiment of the fluid pump of the present application is shown in Figures 1-3, the fluid pump 100 shown includes pump shell 10, impeller 20 arranged in pump shell 10 and the motor 30 of driving impeller 20 rotation in pump shell 10.

[0029] As shown in Figures 1-2, pump shell 10 includes pump shell main body 10a and pump shell cover 10b matched with pump shell main body 10a, wherein impeller 20 is housed in pump shell cover 10b, and motor 30 is housed in pump shell main body 10a.

[0030] The pump housing cover 10b is provided with an inlet 12 and an outlet 14, which are respectively used for connecting with external pipelines to form a fluid flow path. In the illustrated embodiment, the inlet 12 extends along the axial direction of the pump housing cover 10b, and the outlet 14 extends along the tangential direction of the outer circumferential surface of the pump housing cover 10b, and the two are substantially perpendicular to each other. After the fluid enters the pump housing 10 through the inlet 12, it is accelerated and pressurized under the action of the rotating impeller 20 and changes in flow direction, and is discharged from the pump housing 10 through the outlet 14. In other embodiments, the positions, directions, etc. of the inlet 12 and the outlet 14 of the pump housing 10 can be adjusted as needed, and the number of outlets 14 and / or inlets 12 can also be multiple, without being limited to the specific embodiments.

[0031] The impeller 20 is in the shape of a disc, and its outer diameter is slightly smaller than the inner diameter of the pump housing cover 10b, so that after assembly, a gap is formed in the radial direction between the two, so that the impeller 20 can rotate freely in the pump housing 10. In this embodiment, the impeller 20 includes a bottom plate 22 and a cover plate 24 arranged in opposite relation, and a plurality of blades 26 are arranged between the bottom plate 22 and the cover plate 24. Preferably, the blades 26 are integrally formed with the bottom plate 22 by injection molding or the like, and the cover plate 24 is connected to the bottom plate 22 by buckling or the like. In some embodiments, the cover plate 24 and the bottom plate 22 can also be connected together by ultrasonic welding or adhesive bonding. In some embodiments, the cover plate 24 and the bottom plate 22 can also be an integral structure.

[0032] The motor 30 is preferably an inner rotor motor, including a stator 32 and a rotor 34 rotatably arranged in the stator 32. The rotor 34 is connected to the impeller 20 through a rotating shaft 40, so that the motor 30 can drive the impeller 20 to rotate.

[0033] As shown in FIG. 2, the stator 32 includes a stator housing 321, a magnetic core 323 arranged in the stator housing 321, a coil 325 wound on the magnetic core 323, and a circuit board 327 electrically connected to the coil 325, wherein the circuit board 327 is used to connect with an external power supply to supply power to the motor 30. As shown in FIG. 3, the rotor 34 includes an iron core 341, a permanent magnet 343, and a rotor housing 345 covering the iron core 341 and the permanent magnet 343. In this embodiment, the iron core 341 is provided with an assembly hole, and the permanent magnet 343 is embedded into the assembly hole of the iron core 341, and the whole constitutes an IPM motor. In some embodiments, the permanent magnet 343 can also be attached to the outer circumferential surface of the iron core 341, and the whole constitutes an SPM motor.

[0034] After the motor 30 is started, the circuit board 327 provides current for the coil 325 and controls the direction and size of the current in the coil 325, so that the stator 32 can generate a periodically changing rotating magnetic field, which interacts with the magnetic field established by the permanent magnet 343 of the rotor 34 to push the rotor 34 to rotate continuously, thereby driving the impeller 20 to rotate to push the fluid to flow. As shown in FIGS. 6 and 7, the central part of the bottom plate 22 of the impeller 20 is provided with a first shaft hole 28, and the central part of the rotor 34 is provided with a second shaft hole 347, and the two ends of the rotating shaft 40 are respectively arranged in the first shaft hole 28 and the second shaft hole 347 and are fixedly connected with the rotor 34 and the impeller 20 by means of bonding, buckling, welding, bonding or the like, so that the rotor 34 and the impeller 20 can rotate synchronously.

[0035] As shown in FIGS. 3 and 4, the pump shell 10 is provided with a sleeve 50 made of stainless steel or the like, which has a cylindrical structure with one open end 52 and one closed end 54. The open end 52 faces the impeller 20, and the closed end 54 is relatively far away from the impeller 20. The sleeve 50 divides the internal space of the pump shell 10 into relatively independent first and second spaces 16 and 18. The first space 16 is used for assembling the rotor 34 and the impeller 20, and the second space 18 is used for assembling the stator 32. By separating the stator 32 from the rotor 34 and the impeller 20 through the sleeve 50, the fluid only flows in the first space 16, effectively avoiding the fluid from eroding the stator 32 in the second space 18 and affecting the electrical safety of the motor 30 and even the fluid pump 100.

[0036] As shown in FIGS. 3 and 6-7, the two ends of the rotating shaft 40 are respectively provided with a first bearing assembly 42 and a second bearing assembly 44. The first bearing assembly 42 is arranged at the open end 52 of the sleeve 50, and the second bearing assembly 44 is arranged at the closed end 54 of the sleeve 50.

[0037] The first bearing assembly 42 includes a first bearing 45 and a first bearing seat 46 for assembling the first bearing 45. The first bearing 45 is arranged in the central part of the first bearing seat 46 and is internally provided with a first bearing hole for penetrating the first end (such as the top end) of the rotating shaft 40. The second bearing assembly 44 includes a second bearing 47 and a second bearing seat 48 for assembling the second bearing 47. The second bearing 47 is arranged in the central part of the second bearing seat 48 and is internally provided with a second bearing hole for penetrating the second end (such as the bottom end) of the rotating shaft 40. The first bearing 45 and the second bearing 47 are used to support the rotation of the rotating shaft 40, the rotor 34 and the impeller 20, which can be sliding bearings, ball bearings, shaft bushings or the like. The types of the first bearing 45 and the second bearing 47 can be the same or different.

[0038] In the present application, the rotating shaft 40 is fixedly connected with the impeller 20 and the rotor 34 and rotates synchronously. By arranging the first bearing 45 and the second bearing 47, effective support is formed on both ends of the rotating shaft 40, and when the rotating shaft 40 rotates synchronously with the impeller 20 and the rotor 34, even if the impeller 20 is subjected to uneven force in the circumferential direction, the rotating shaft 40 can always be kept in a coaxial state with the stator 32, so that the rotor 34 and the impeller 20 are kept in a coaxial state with the stator 32, avoiding the influence of the deflection of the rotating shaft 40 on the smooth rotation of the rotor 34 and the impeller 20, and avoiding the stress caused thereby to damage the elements, thereby ensuring the stability and safety of the operation of the fluid pump 100, reducing the generation of noise, and prolonging the service life.

[0039] As shown in FIG. 6, the open end 52 of the sleeve 50 extends outward in the radial direction to form a first flange 56. The first bearing seat 46 has a whole disc structure, and is stacked on the outside of the first flange 56 of the sleeve 50.

[0040] Preferably, the first flange 56 is outwardly convex to form a convex part 57, such as a convex column or a convex strip, and the first bearing seat 46 is inwardly concave to form a concave part 461, such as a perforation or a concave groove, at a position corresponding to the convex part 57. During assembly, the convex part 57 of the sleeve 50 is aligned with the concave part 461 of the first flange 56 and is concave-convex matched, thereby positioning the first bearing seat 46 and the sleeve 50 in the circumferential direction. In other embodiments, a convex part can be arranged on the first bearing seat 46, and a concave part can be correspondingly arranged on the first flange 56, and the positioning in the circumferential direction is also achieved by concave-convex matching. Of course, the first bearing seat 46 and the sleeve 50 can also be positioned in the circumferential direction by other means, such as buckling.

[0041] In some embodiments, the outer edge of the first flange 56 of the sleeve 50 is bent to extend to form an annular folded edge 58, and the end of the folded edge 58 is further bent to extend to form a second flange 59, which extends outward in the radial direction of the sleeve 50 and is clamped between the pump shell cover 10b and the stator shell 321 in the axial direction, as shown in FIG. 3. Preferably, the second flange 59 of the sleeve 50 is provided with a sealing member, such as a sealing ring, between the pump shell cover 10b and the stator shell 321, respectively, to ensure the sealing of the entire fluid pump 100. In this way, the fluid in the first space 16 can be prevented from being exposed outside the fluid pump 100, and water vapor, dust and the like in the external environment can also be prevented from entering the second space 18 of the fluid pump 100, thereby ensuring the safety of use.

[0042] In the illustrated embodiment, the stator 32 is assembled to the pump shell main body 10a and partially extends out of the pump shell main body 10a, the pump shell cover 10b is stacked on the stator shell 321, the second flange 59 of the sleeve 50 is clamped between the pump shell cover 10b and the stator shell 321, and the fixing member such as a screw is screwed and connected with the pump shell cover 10b after penetrating through the pump shell main body 10a, the stator shell 321 and the second flange 59. It should be understood that the pump shell 10 generally refers to the outermost shell structure of the entire pump, and the stator shell 321 can also be regarded as a part of the pump shell 10.

[0043] The first bearing seat 46 further divides the first space 16 into a first subspace 161 and a second subspace 163, wherein the first subspace 161 is the space between the pump shell cover 10b and the first bearing seat 46, corresponding to the open end 52 of the sleeve 50, for arranging the impeller 20; the second subspace 163 is the internal space of the sleeve 50, for arranging the rotor 34; the stator 32 is arranged in the second space 18, wherein the magnetic core 323 is sleeved around the sleeve 50, and the circuit board 327 is attached to the closed end 54 of the sleeve 50. During the operation of the motor 30, a large amount of heat is generated from the stator 32, especially the circuit board 327 of the stator 32, which can be conducted to the sleeve 50 for dissipation.

[0044] The first bearing seat 46 is provided with a through hole 463 at a position corresponding to the second subspace 163, which communicates the first subspace 161 and the second subspace 163. The number of through holes 463 can be single or multiple, which extend through the first bearing seat 46 in the axial direction, so that the fluid can flow from the first subspace 161 where the impeller 20 is located to the second subspace 163 in the sleeve 50, and then exchange heat with the sleeve 50, thereby dissipating heat from the stator 32, especially the circuit board 327 of the stator 32.

[0045] The flow channel 41 is formed in the shaft 40, the number of flow channels 41 can be single or multiple, which extend along the axial direction of the shaft 40 and communicate the second subspace 163 and the first subspace 161, so that the fluid after absorbing heat can flow back from the second subspace 163 to the first subspace 161, and finally be discharged to the outside by the outlet 14 under the action of the impeller 20. In the present embodiment, the bottom end of the shaft 40 is spaced apart from the closed end 54 of the sleeve 50, and the top end is between the cover plate 24 and the bottom plate 22 of the impeller 20, i.e. directly opposite the position where the impeller 20 is located. The flow channel 41 penetrates through both ends of the shaft 40 in the axial direction, so that the fluid in the second subspace 163 can enter the flow channel 41 from the bottom end of the shaft 40, and then flow to the space between the blades 26 from the top end of the shaft 40, and return to the first subspace 161.

[0046] In some embodiments, any one end of the flow channel 41 can also extend through the circumferential outer wall surface of the shaft 40 by bending, at this time the fluid flows into / out of the flow channel 41 in the radial direction.

[0047] As shown in FIG. 6 and FIG. 7, the second bearing seat 48 comprises an inner ring 481 located in the center, an outer ring 483 arranged around the inner ring 481, and a plurality of ribs 485 connected between the inner ring 481 and the outer ring 483. The inner ring 481 is provided with an assembly hole 482 in the center for mounting the second bearing 47. The outer diameter of the outer ring 483 is substantially equal to or slightly smaller than the inner diameter of the sleeve 50, so that the second bearing seat 48 can be conveniently assembled into the sleeve 50 and preliminarily positioned with the sleeve 50. The plurality of ribs 485 are arranged at intervals in the circumferential direction of the second bearing seat 48, and a passage 487 is formed between two adjacent ribs 485, so that the fluid can flow more smoothly through the second bearing seat 48 to the closed end 54 of the sleeve 50.

[0048] In this embodiment, the axial height of the outer ring 483 is greater than the axial height of the inner ring 481, and the outer ring 483 protrudes outward by a certain length in the axial direction relative to the inner ring 481 and toward the closed end 54 of the sleeve 50. After assembly, the outer ring 483 abuts the closed end 54 of the sleeve 50 in the axial direction, and the inner ring 481 is arranged at intervals with the closed end 54 of the sleeve 50 in the axial direction. Preferably, the side end of the shaft 40 and the inner ring 481 toward the closed end 54 of the sleeve 50 are substantially flush, so that the inner ring 481, the shaft 40 and the closed end 54 of the sleeve 50 are all spaced a certain height in the axial direction, and thus the passage 487 can be in communication with the flow channel 41 of the shaft 40, and the fluid can flow back to the flow channel 41 of the shaft 40 through the second bearing seat 48.

[0049] In this embodiment, the second bearing assembly 44 further comprises a fixing member 49 for fixing the second bearing seat 48 into the sleeve 50.

[0050] Specifically, the fixing member 49 comprises a first ring part 491, a second ring part 493 and a positioning part 495, wherein the first ring part 491 is fitted with the circumferential inner wall of the sleeve 50 and can be fixedly connected with the same by welding, tight fit or the like; the second ring part 493 extends radially inwardly from the first ring part 491 and abuts the second bearing seat 48 in the axial direction, so that the second bearing seat 48 is clamped between the second ring part 493 and the closed end 54 of the sleeve 50 and positioned in the axial direction; and the positioning part 495 extends axially from the first ring part 491 toward the second bearing seat 48, and the outer wall of the second bearing seat 48 is provided with a positioning groove 489 matched with the positioning part 495, so that the second bearing seat 48 is positioned in the circumferential direction by the cooperation of the positioning part 495 and the positioning groove 489.

[0051] Specifically, the positioning portions 495 can be positioning pieces, and the number thereof can be single or multiple. Preferably, the number of the positioning portions 495 is multiple, and the positioning portions 495 are spaced apart along the circumference of the fixing member 49. Each of the positioning portions 495 is integrally extended from the first ring portion 491 toward the second bearing seat 48, and the second bearing seat 48 is provided with a plurality of positioning grooves 489 on the outer wall thereof, each of the positioning grooves 489 extending along the axial direction for a certain length. During assembly, the positioning portions 495 of the fixing member 49 are aligned with the positioning grooves 489 of the second bearing seat 48 one by one and are inserted into each other until the second ring portion 493 abuts against the end surface of the second bearing seat 48; then, the first ring portion 491 is fixedly connected with the circumferential inner wall of the sleeve 50, and the second bearing seat 48 is fixed in the sleeve 50. To facilitate the arrangement of the positioning portions 495, the second ring portion 493 can be opened at positions corresponding to the positioning portions 495, so that the second ring portion 493 appears as a plurality of arc-shaped pieces.

[0052] In other embodiments, the second ring portion 493 can abut against the second bearing seat 48 in the axial direction in other forms, for example, the second ring portion 493 is on the same circumference as the first ring portion 491 and directly abuts against or is inserted into the top of the second bearing seat 48. In other embodiments, the positioning portions 495 can also extend radially from the first ring portion 491 or the second ring portion 493 and be inserted into the second bearing seat 48, so as to position the second bearing seat 48 in the circumferential direction.

[0053] During operation of the fluid pump 100, fluid enters the pump housing 10 through the inlet 12, is driven by the rotation of the impeller 20, and flows out of the pump housing 10 through the outlet 14. During rotation of the impeller 20, the first bearing assembly 42 and the second bearing assembly 44 provide effective support for the two ends of the rotating shaft 40, so as to avoid uneven force in the circumferential direction of the impeller 20 from causing the rotating shaft 40 to yaw, thereby ensuring the stability and safety of the rotation of the rotor 34 and the impeller 20. A small amount of fluid enters the sleeve 50 through the perforations 463 in the first bearing seat 46, and then returns to the impeller 20 through the flow channel 41 of the rotating shaft 40. During this process, the fluid exchanges heat with the sleeve 50 and carries away the heat of the stator 32, so that the motor 30 always operates at an appropriate temperature, avoids failure, and improves electrical safety.

[0054] It should be noted that the above embodiments only express the preferred embodiments of the present application, and the description is more specific and detailed, but it should not be construed as a limitation of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, such as combining different features in the various embodiments, and these should all fall within the scope of protection of the present application.

Claims

1. A fluid pump comprising a pump housing, an impeller disposed in the pump housing, and a motor driving the impeller to rotate in the pump housing, characterized by, The motor comprises a stator and a rotor, the rotor is fixedly connected with the impeller through a rotating shaft; a sleeve is arranged in the pump shell, the sleeve divides the internal space of the pump shell into a first space and a second space, the rotor, the rotating shaft and the impeller are movably arranged in the first space, and the stator is fixedly arranged in the second space; the rotating shaft is provided with a first bearing assembly and a second bearing assembly at two ends respectively, and the second bearing assembly is located at one end of the sleeve away from the impeller and is fixedly connected with the sleeve.

2. The fluid pump of claim 1, wherein, The sleeve is a cylindrical structure with one end open and one end closed, and the second bearing assembly is accommodated in the sleeve and located at the closed end of the sleeve.

3. The fluid pump of claim 2, wherein, The second bearing assembly comprises a second bearing seat and a second bearing, the second bearing seat comprises an inner ring and an outer ring arranged around the inner ring, the second bearing is arranged in the inner ring, the inner ring is arranged axially away from the closed end of the sleeve, and the outer ring abuts axially against the closed end of the sleeve.

4. The fluid pump of claim 3, wherein, The second bearing seat further comprises a plurality of ribs connected between the inner ring and the outer ring, the plurality of ribs are arranged at intervals in the circumferential direction, and a channel is formed between adjacent two ribs.

5. The fluid pump of claim 3, wherein, The rotating shaft is arranged axially away from the closed end of the sleeve, and an axial flow channel is formed in the rotating shaft.

6. The fluid pump of claim 3, wherein, The second bearing assembly further comprises a fixing member fastened to the sleeve, and the fixing member positions the second bearing seat at one end of the sleeve away from the impeller.

7. The fluid pump of claim 6, wherein, The fixing member comprises a first ring portion and a second ring portion, the first ring portion is fixedly connected with the circumferential inner wall of the sleeve, and the second bearing seat is clamped axially between the second ring portion and the closed end of the sleeve.

8. The fluid pump of claim 7, wherein, The fixing member further comprises a positioning piece extending axially from the first ring portion towards the second bearing seat, an outer wall of the second bearing seat is provided with an axially extending positioning groove, and the positioning piece is inserted into the positioning groove to position the second bearing seat in the circumferential direction.

9. The fluid pump of claim 7, wherein, The first ring portion is interference-fitted or welded with the circumferential inner wall of the sleeve.

10. The fluid pump of any one of claims 2-9, wherein, The first bearing assembly comprises a first bearing seat and a first bearing arranged in the first bearing seat, the first bearing seat is arranged outside the open end of the sleeve, and the first bearing seat divides the first space into a first sub-space and a second sub-space, the impeller is arranged in the first sub-space, and the rotor is arranged in the second sub-space. The first bearing seat is provided with a through hole, and the through hole communicates the first sub-space and the second sub-space.

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