CN117536886A

CN117536886A - Wet-type servo permanent magnet pump

Info

Publication number: CN117536886A
Application number: CN202311657630.1A
Authority: CN
Inventors: 徐伏兴; 徐继庄; 操瑞嘉
Original assignee: Suzhou Ruiman Chemical Equipment Co ltd
Current assignee: Suzhou Ruiman Chemical Equipment Co ltd
Priority date: 2023-12-06
Filing date: 2023-12-06
Publication date: 2024-02-09

Abstract

The invention belongs to the technical field of leakage-free vane type pumps, and particularly relates to a wet type servo permanent magnet pump which comprises a driving part, wherein the driving part comprises a fixed shell, a servo motor stator, a spacer sleeve, a permanent magnet rotor, a heat dissipation hole and a fixed end cover, the fixed shell is fixed with an external fixing piece through bolts, the servo motor stator is fixedly connected with the inner side of the fixed shell, the outer edge of the spacer sleeve is matched with the inner side of the servo motor stator, a port at one end of the spacer sleeve is matched with a port at one side of the fixed shell, the permanent magnet rotor is arranged on the inner side of the spacer sleeve, the heat dissipation hole is fixedly connected with a port at the other side of the fixed shell, and the fixed end cover is fixedly connected with the fixed part inside the permanent magnet rotor. The permanent magnet synchronous servo motor drives the impeller to rotate, so that fluid or slurry is safely and leak-free conveyed, meanwhile, the whole structure of the equipment is compact, a complex welding process is not needed, the equipment is convenient to assemble and disassemble, and the maintenance performance is good.

Description

Wet-type servo permanent magnet pump

Technical Field

The invention belongs to the technical field of leakage-free vane pumps, and particularly relates to a wet-type servo permanent magnet pump.

Background

The non-leakage volumetric pump is a machine capable of safely conveying dangerous fluid or precious liquid, and because the non-leakage volumetric pump is not provided with a mechanical seal, the variable seal is a static seal, so that the problems of leakage and lubrication are effectively solved. Therefore, the method can be widely applied to corrosive medium transportation, chlorine water wastewater treatment and acid adding processes in chemical production, electrolyte transportation in nonferrous metal smelting, acid washing processes in automobile manufacturing, and a plurality of industries such as pharmacy, petroleum, electric power, electroplating, dye, pesticide, papermaking, food, textile and the like. Sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid, aqua regia, strong alkali, strong oxidant, organic solvent, reducer and other strong corrosive medium. Or other liquid or liquid mixture that is not leak-able.

Today there are mainly two forms of leak-free rotary pumps on the market, one being a canned pump.

As in chinese patent 201310661903.X, a canned motor pump is disclosed, wherein the impeller of the pump is fixed on the rotor shaft extension of the canned motor, and the pump and the motor are integrated; the rotor support bearing is a medium-lubricated water guide bearing, motor power is transmitted to the rotor through a stator magnetic field, and the rotor runs in the conveyed medium. The rotor and the stator of the motor are covered by the shielding sleeve and are separated from the medium. This construction eliminates the rotary shaft seal that a conventional centrifugal pump must have.

As further disclosed in chinese patent 202210896582.0, a typical leak-free rotary pump is a magnetically driven pump, and comprises a pump head, a magnetic coupling, and a standard motor. The magnetic coupling consists of an outer magnetic steel, an inner magnetic steel and a non-magnetic or weak magnetic isolation sleeve. When the motor drives the outer magnetic rotor to rotate, the magnetic field can penetrate through the air gap and the non-magnetic substance to drive the inner magnetic rotor connected with the impeller to synchronously rotate, so that the non-contact transmission of power is realized. The magnetic coupling is used for converting the dynamic seal into the static seal. Because the pump shaft and the inner magnetic steel are completely sealed by the pump body and the isolation sleeve, the problems of running, overflowing, dripping and leaking are thoroughly solved.

However, the above devices have disadvantages in that, for the canned pump, the inner and outer rotors are isolated by the canned jacket, and a static seal of the fluid is achieved. But since the shield is typically welded to the pump housing. Once the outer rotor of the canned motor pump fails, repair and maintenance of the equipment is not facilitated. Meanwhile, the welding requirement of the shielding sleeve is limited, and the shielding sleeve can only be made of hastelloy or austenitic stainless steel. The magnetic induction lines typically do not pass completely through the shield and typically experience reduced efficiency of the drive motor due to eddy current effects in the shield. Meanwhile, the influence of disc loss on a motor rotor is considered, and the efficiency of the unit is about 5% -10% lower than that of a mechanical seal pump;

the magnetic pump adopts the isolation sleeve to replace the shielding sleeve, and the production process is simpler than that of the shielding sleeve during assembly and manufacture. The driving motor is usually not required, but the energy conversion efficiency of the similar equipment is low, and the driving power depends on the motor-magnetic rotor-to-the driving end of the impeller. The driving mode requires more parts and increases the probability of equipment failure.

Disclosure of Invention

The invention aims to provide a wet-type servo permanent magnet pump which can drive an impeller to rotate through a permanent magnet synchronous servo motor so as to safely convey and discharge fluid or slurry without leakage, and meanwhile, the whole structure of the equipment is compact, a relatively complex welding process is not needed, the equipment is convenient to assemble and disassemble, and the maintenance is good.

The technical scheme adopted by the invention is as follows:

the utility model provides a wet-type servo permanent magnet pump, includes drive division, drive division includes fixed casing, servo motor stator, spacer sleeve, permanent magnet rotor, louvre and fixed end cover, fixed casing passes through the bolt fastening with outside mounting, servo motor stator and fixed casing's inboard fixed connection, the outer fringe of spacer sleeve cooperatees with servo motor stator's inboard, and the port of spacer sleeve one end cooperatees with the port of fixed casing one side, permanent magnet rotor sets up in the inboard of spacer sleeve, the louvre is seted up at fixed casing's outer fringe to cooperate with the spacer sleeve, fixed end cover with permanent magnet rotor's inside fixedly connected with fixed part, the one end fixedly connected with delivery impeller of fixed part, one side of delivery impeller is provided with the pump case, the pump case cooperatees with fixed casing's port to through bolt fastening.

In a preferred scheme, a heat dissipation groove is formed in the other end of the isolation sleeve, and the heat dissipation groove is matched with the heat dissipation hole.

In a preferred scheme, a plurality of liquid guide grooves are formed in the inner edge of the isolation sleeve.

In a preferred scheme, the fixed part comprises a pump shaft, a bearing seat, a front thrust disc, a front shaft sleeve, a rear thrust disc and an inner impeller, one end of the pump shaft is fixedly connected with the inner side of the permanent magnet rotor, the other end of the pump shaft is fixedly connected with the conveying impeller, two ends of the pump shaft are fixedly connected with the permanent magnet rotor and the conveying impeller through locking nuts, the inner part of the bearing seat is rotationally connected with the outer edge of the pump shaft, the outer edge of one end of the bearing seat is positioned between the ports of the pump housing and the isolation sleeve, the front thrust disc is fixedly connected with the other end of the bearing seat, the front shaft sleeve is fixedly connected with one end of the inner side of the bearing seat, the front shaft sleeve is rotationally connected with the outer edge of the middle part of the pump shaft, the rear thrust disc is fixedly connected with the other end of the bearing seat, and the axle center of the inner impeller is positioned at the other end of the pump shaft through threads.

In a preferred scheme, the inner side of the pump shell is in a stepped opening shape, one end of the bearing seat is arranged on the inner side of the pump shell, one end of the bearing seat is matched with the port of the isolation sleeve, the isolation sleeve is extruded by the fixed shell to be arranged at one end of the bearing seat, and the fixed shell is connected with the pump shell through bolts.

In a preferred scheme, the whole of pump shaft sets up to the step shaft, the keyway has been seted up at the both ends of pump shaft, the keyway cooperatees with the inside of conveying impeller and permanent magnet rotor.

In a preferred scheme, a hollow inner flow hole is formed in the pump shaft, a through hole perpendicular to the axis direction is formed in the middle section of the pump shaft, and the through hole is communicated with the inner flow hole.

In a preferred scheme, a flow hole is formed in one end of the bearing seat.

In a preferred embodiment, the front thrust disc and the rear thrust disc are provided with annular grooves for allowing the front sleeve and the rear sleeve to extend partially into the thrust discs.

In a preferred embodiment, the direction of the cambered surfaces of the blades inside the conveying impeller and the inner impeller is opposite.

The invention has the technical effects that:

compared with a shielding pump, the shielding sleeve is replaced by the isolating sleeve, a complex welding process is abandoned, the isolating sleeve and the isolating sleeve are spliced and fixed by utilizing bolts to extrude the fixing shell and the pump shell, so that a closed space is formed inside the pump shell and the isolating sleeve, and the four parts are separated only by detaching the bolts during maintenance, thereby improving the maintainability of equipment;

compared with the traditional magnetic pump, the invention adopts the design of the driving part and the fixing part, and adopts the structure that the stator is arranged outside the isolation sleeve, the magnetic rotor is arranged inside the isolation sleeve to directly drive the workpiece to rotate, thereby simplifying the transmission way of force, simultaneously enabling the whole parts of the pump unit to be more compact, and having the advantages of small volume and high efficiency;

the invention adopts the design of the driving part, the driving source used belongs to the structure of the servo motor, the design theory of the alternating current magnetic circuit is mature, the pump can obtain relatively high energy transmission efficiency, and the precise regulation and control of the pump impeller can be realized through the rotary encoder, so that the precise flow of liquid is controlled.

Drawings

FIG. 1 is a schematic overall view of an embodiment of the present invention;

FIG. 2 is an overall cross-sectional view of an embodiment of the invention;

FIG. 3 is an overall internal exploded view of an embodiment of the present invention;

FIG. 4 is a schematic view of a fixing portion according to an embodiment of the present invention;

FIG. 5 is a schematic view of a pump shaft, a delivery impeller, and a permanent magnet rotor of an embodiment of the present invention;

FIG. 6 is a schematic diagram of an embodiment of the spacer sleeve of the present invention;

fig. 7 is a schematic view of a bearing housing according to an embodiment of the present invention.

In the drawings, the list of components represented by the various numbers is as follows:

1. a driving section; 101. a fixed housing; 102. a servo motor stator; 103. a spacer sleeve; 104. a permanent magnet rotor; 105. a heat radiation hole; 106. fixing the end cover; 2. a fixing part; 201. a pump shaft; 202. a bearing seat; 203. a front thrust plate; 204. a front sleeve; 205. a rear sleeve; 206. a rear thrust plate; 207. an inner impeller; 3. a delivery impeller; 4. and a pump shell.

Detailed Description

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present invention is not limited to the specific embodiments disclosed below.

Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the invention. The appearances of the phrase "in one preferred embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Further, in describing the embodiments of the present invention in detail, the cross-sectional view of the device structure is not partially enlarged to a general scale for convenience of description, and the schematic is only an example, which should not limit the scope of protection of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.

Referring to fig. 1 to 6, the present invention provides a wet-type servo permanent magnet pump, which comprises a driving part 1, wherein the driving part 1 comprises a fixed housing 101, a servo motor stator 102, a spacer sleeve 103, a permanent magnet rotor 104, a heat dissipation hole 105 and a fixed end cover 106, the fixed housing 101 is fixed with an external fixing part through bolts, the servo motor stator 102 is fixedly connected with the inner side of the fixed housing 101, the servo motor stator 102 is electrically connected with an encoder, the servo motor structure is a mature prior art, the outer edge of the spacer sleeve 103 is matched with the inner side of the servo motor stator 102, a port at one end of the spacer sleeve 103 is matched with a port at one side of the fixed housing 101, the permanent magnet rotor 104 is arranged at the inner side of the spacer sleeve 103, the heat dissipation hole 105 is formed at the outer edge of the fixed housing 101 and matched with the spacer sleeve 103, the fixed end cover 106 is fixedly connected with a fixed part 2 inside the permanent magnet rotor 104, one end of the fixed part 2 is fixedly connected with a conveying impeller 3, one side of the conveying impeller 3 is provided with a pump shell 4, and the pump shell 4 is fixedly connected with a port of the fixed housing 101 through bolts.

Specifically, when the servo motor stator 102 is energized, an induced magnetic field is generated near the servo motor stator 102, and then the permanent magnet rotor 104 is driven to rotate, the permanent magnet rotor 104 drives the fixed part 2 to rotate, and then the conveying impeller 3 rotates, and the rotating conveying impeller 3 sucks fluid from the suction inlet of the pump casing 4 and conveys the fluid to the outlet end of the pump casing 4. Wherein, part of fluid leaks into the cavity inside the isolation sleeve 103 from the position of the delivery impeller 3 through the gap of the small hole on the fixed part 2, and the liquid flows back to the position of the inlet of the delivery impeller 3 due to the rotation of the fixed part 2, so that the delivery of the liquid by the impeller and the circulation of the liquid between the pump shell 4 and the isolation sleeve 103 are realized through the process, the working temperature of the permanent magnet rotor 104 and the fixed part 2 is reduced, and the service life is prolonged.

Referring to fig. 2, 3 and 6, in this embodiment, a heat dissipation groove is formed at the other end of the isolation sleeve 103, and the contact area between the isolation sleeve 103 and air is increased by the heat dissipation groove, so that the heat absorbed by the isolation sleeve 103 is conducted in the air in an accelerating manner, thereby reducing the temperature of the isolation sleeve 103, the heat dissipation groove is matched with the heat dissipation hole 105, and the air around the heat dissipation groove is promoted to flow through the heat dissipation hole 105, so that the heat of the isolation sleeve 103 is conducted to the outside of the fixed housing 101, the heat accumulation is avoided, and the heat dissipation efficiency of the isolation sleeve 103 is improved.

Referring to fig. 2, 3 and 6, in this embodiment, a plurality of liquid guiding tanks are formed at the inner edge of the isolation sleeve 103, and the liquid guiding tanks convey the flowing liquid at the position of the conveying impeller 3 to the inside of the isolation sleeve 103, so as to accelerate the flowing speed of the liquid, further quickly absorb and flow away the heat at the position of the isolation sleeve 103, reduce the temperature of the isolation sleeve 103 and the permanent magnet rotor 104, and avoid high temperature damage.

Referring to fig. 2 to 5, in this embodiment, the fixing portion 2 includes a pump shaft 201, a bearing housing 202, a front thrust disc 203, a front shaft sleeve 204, a rear shaft sleeve 205, a rear thrust disc 206 and an inner impeller 207, one end of the pump shaft 201 is fixedly connected with the inner side of the permanent magnet rotor 104, the other end of the pump shaft 201 is fixedly connected with the delivery impeller 3, and both ends of the pump shaft 201 are fixedly connected with the permanent magnet rotor 104 and the delivery impeller 3 through lock nuts, when the permanent magnet rotor 104 rotates, power is transmitted to the delivery impeller 3 through the pump shaft 201 and the delivery impeller 3 is driven to rotate, so that liquid inside the pump housing 4 is sucked from a suction inlet through rotation of the delivery impeller 3 and is delivered to an outlet end of the pump housing 4, the inside of the bearing housing 202 is rotatably connected with an outer edge of the pump shaft 201, and an outer edge of one end of the bearing housing 202 is located between the pump housing 4 and a port of the isolation sleeve 103, the front thrust disc 203 is fixedly connected with the other end of the bearing seat 202, the front shaft sleeve 204 is fixedly connected with one end of the inner side of the bearing seat 202, the rear shaft sleeve 205 is fixedly connected with the other end of the inner side of the bearing seat 202, the insides of the front shaft sleeve 204 and the rear shaft sleeve 205 are both rotationally connected with the outer edge of the middle part of the pump shaft 201, the friction force during the rotation of the pump shaft 201 is reduced through the front shaft sleeve 204 and the rear shaft sleeve 205, the abrasion of the pump shaft 201 is further reduced, the service life of the pump shaft 201 is prolonged, the rear thrust disc 206 is fixedly connected with the other end of the bearing seat 202, the corresponding front shaft sleeve 204 and the rear shaft sleeve 205 are limited through the front thrust disc 203 and the rear thrust disc 206, the pump shaft 201 is prevented from moving in the rotation driving of the front shaft sleeve 204 and the rear shaft sleeve 205, the normal work of equipment is influenced, the other end of the inner impeller 207 is rotationally connected with the pump shaft 201 through threads, and then the liquid at the inner impeller 207 is sucked into the pump shaft 201, and the liquid circulation in the isolation sleeve 103 is accelerated by matching with the liquid guide groove, so that the liquid is conveyed and circulated through the structure.

Referring to fig. 2, in this embodiment, the inner side of the pump casing 4 is in a stepped opening shape, one end of the bearing seat 202 is disposed on the inner side of the pump casing 4, a sealing ring is disposed between the bearing seat 202 and the pump casing 4, one end of the bearing seat 202 and a port of the isolation sleeve 103 are in an inserting manner, a sealing ring is also disposed between the bearing seat 202 and the isolation sleeve 103, the isolation sleeve 103 is pressed by the fixed casing 101 to be seated on one end of the bearing seat 202, and the fixed casing 101 is fixedly connected with the pump casing 4 through bolts, so that when the fixed casing 101 and the pump casing 4 are pressed and spliced by the bolts, the bearing seat 202 and the isolation sleeve 103 between them are pressed and spliced together, and a closed space is formed between the pump casing 4 and the isolation sleeve 103 through the above process; when maintenance and repair are needed, the pump shell 4, the bearing seat 202, the isolation sleeve 103 and the fixed shell 101 can be separated only by detaching the bolts of the fixed shell 101 and the pump shell 4, so that the disassembly of equipment is realized, and the maintenance difficulty of maintenance is reduced.

Referring to fig. 2 to 5, in this embodiment, the pump shaft 201 is integrally configured as a stepped shaft, and when the delivery impeller 3 and the permanent magnet rotor 104 are mounted at two ends of the pump shaft 201, the stepped shaft is designed to provide limit for both ends of the pump shaft 201, two ends of the pump shaft 201 are provided with key slots, the key slots are matched with the interior of the delivery impeller 3 and the interior of the permanent magnet rotor 104, and the key slots provide limit for the delivery impeller 3 and the permanent magnet rotor 104, so that both rotate together with the pump shaft 201; meanwhile, the key slot can also provide installation guide for installation of the conveying impeller 3 and the permanent magnet rotor 104, so that convenient installation is realized.

Referring to fig. 2 to 5, in this embodiment, a hollow inner flow hole is formed in the pump shaft 201, a through hole perpendicular to the axial direction is formed in the middle section of the pump shaft 201, the through hole is communicated with the inner flow hole, and the delivery impeller 3 can form a negative pressure area at the axial center when the pump shaft 201 rotates, so that liquid can be sucked into the delivery impeller 3 through the inner flow hole of the pump shaft 201 to the liquid in the isolation sleeve 103, thereby realizing the delivery of the liquid through the inner flow hole.

Referring to fig. 7, in this embodiment, a flow hole is formed in an inner portion of one end of the bearing housing 202, the flow hole communicates an inner portion of the pump housing 4 with an inner portion of the spacer 103, and when the delivery impeller 3 rotates, liquid in the pump housing 4 is pumped into the inner portion of the spacer 103 through the flow hole, and space communication is achieved through the flow hole and no guide is provided for the flow of the liquid.

Referring to fig. 2-4, in this embodiment, the front thrust disk 203 and the rear thrust disk 206 are provided with annular grooves that allow the front hub 204 and the rear hub 205 to partially penetrate into the thrust disk, the annular grooves providing a fixation and a stop for the front hub 204 and the rear hub 205.

Referring to fig. 4, in this embodiment, the cambered surfaces of the blades inside the conveying impeller 3 and the inner impeller 207 are opposite, and a guiding cone is arranged inside the inner impeller 207, when the pump shaft 201 rotates, the conveying impeller 3 and the inner impeller 207 are driven to rotate together, so that the liquid at the conveying impeller 3 is guided by the cambered surfaces of the blades, and the liquid flows to the outer edge of the conveying impeller 3; at the same time, when the inner impeller 207 rotates, the surrounding liquid is guided by the fan surface, so that the liquid moves to the inner side of the inner impeller 207 and is guided to the inside of the pump shaft 201 by the guide cone, thereby accelerating the liquid delivery, and the liquid in the pump shell 4 and the isolation sleeve 103 forms a circulation, thereby reducing the working temperature of the permanent magnet rotor 104 and prolonging the service life.

The working principle of the invention is as follows: when the servo motor stator 102 is electrified, an induced magnetic field is generated near the servo motor stator 102, so that the permanent magnet rotor 104 is driven to rotate, the permanent magnet rotor 104 drives the fixed part 2 to rotate, the conveying impeller 3 rotates, and the rotating conveying impeller 3 sucks fluid from the suction inlet of the pump shell 4 and conveys the fluid to the outlet end of the pump shell 4. Wherein, part of fluid leaks into the cavity inside the isolation sleeve 103 from the position of the delivery impeller 3 through the gap of the small hole on the fixed part 2, and the liquid flows back to the position of the inlet of the delivery impeller 3 due to the rotation of the fixed part 2, so that the delivery of the liquid by the impeller and the circulation of the liquid between the pump shell 4 and the isolation sleeve 103 are realized through the process, the working temperature of the permanent magnet rotor 104 and the fixed part 2 is reduced, and the service life of the permanent magnet rotor is prolonged.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention. Structures, devices and methods of operation not specifically described and illustrated herein, unless otherwise indicated and limited, are implemented according to conventional means in the art.

Claims

1. A wet-type servo permanent magnet pump, characterized in that: including drive portion (1), drive portion (1) is including fixed casing (101), servo motor stator (102), spacer sleeve (103), permanent magnet rotor (104), louvre (105) and fixed end cover (106), fixed casing (101) pass through the bolt fastening with outside mounting, servo motor stator (102) and the inboard fixed connection of fixed casing (101), the outer fringe of spacer sleeve (103) cooperatees with the inboard of servo motor stator (102), and the port of spacer sleeve (103) one end cooperatees with the port of fixed casing (101) one side, permanent magnet rotor (104) set up in the inboard of spacer sleeve (103), louvre (105) are seted up in the outer fringe of fixed casing (101) to cooperate with spacer sleeve (103), fixed end cover (106) with the inside fixedly connected with fixed part (2) of permanent magnet rotor (104), the one end fixedly connected with of fixed part (2) carries impeller (3), one side of carrying impeller (3) is provided with (4), pump case (4) cooperatees with the port of fixed casing (101) and passes through bolt fastening.

2. A wet servo permanent magnet pump according to claim 1, wherein: the other end of the isolation sleeve (103) is provided with a heat dissipation groove which is matched with the heat dissipation hole (105).

3. A wet servo permanent magnet pump according to claim 1, wherein: the inner edge of the isolation sleeve (103) is provided with a plurality of liquid guide tanks.

4. A wet servo permanent magnet pump according to claim 1, wherein: the utility model provides a fixed part (2) is including pump shaft (201), bearing frame (202), preceding thrust disk (203), preceding axle sleeve (204), back axle sleeve (205), back thrust disk (206) and interior impeller (207), the inboard fixed connection of one end and permanent magnet rotor (104) of pump shaft (201), the other end and the transport impeller (3) fixed connection of pump shaft (201), and the both ends of pump shaft (201) pass through lock nut and permanent magnet rotor (104) and transport impeller (3) fixed connection, the inside of bearing frame (202) is rotated with the outer fringe of pump shaft (201) and is connected, and the outer fringe of the one end of bearing frame (202) is in between the port of pump casing (4) and spacer sleeve (103), the other end fixed connection of preceding thrust disk (203) and bearing frame (202), the one end fixed connection of preceding axle sleeve (204) and bearing frame (202) inboard, the other end fixed connection of back axle sleeve (205) and bearing frame (202) inboard, the inside of preceding axle sleeve (204) and back axle sleeve (205) all rotates with the outer fringe in middle part of impeller (201), the other end of bearing frame (206) is in fixed connection through the screw thread of pump shaft (201).

5. A wet servo permanent magnet pump according to claim 4 wherein: the inner side of the pump shell (4) is in a stepped opening shape, one end of the bearing seat (202) is arranged on the inner side of the pump shell (4), one end of the bearing seat (202) is matched with a port of the isolation sleeve (103), the isolation sleeve (103) is extruded by the fixed shell (101) to be seated at one end of the bearing seat (202), and the fixed shell (101) is connected with the pump shell (4) through bolts.

6. A wet servo permanent magnet pump according to claim 4 wherein: the whole of pump shaft (201) sets up to the step shaft, the keyway has been seted up at the both ends of pump shaft (201), the inside of keyway and conveying impeller (3) cooperatees with the inside of permanent magnet rotor (104).

7. A wet servo permanent magnet pump according to claim 4 wherein: the inside of pump shaft (201) has seted up hollow interior flow hole to the through-hole of perpendicular to axis direction is seted up at the middle section of pump shaft (201), the through-hole is linked together with interior flow hole.

8. A wet servo permanent magnet pump according to claim 4 wherein: a flow hole is formed in one end of the bearing seat (202).

9. A wet servo permanent magnet pump according to claim 4 wherein: the front thrust disc (203) and the rear thrust disc (206) are provided with annular grooves, so that the front shaft sleeve (204) and the rear shaft sleeve (205) can partially penetrate into the thrust discs.

10. A wet servo permanent magnet pump according to claim 1, wherein: the cambered surface directions of the blades inside the conveying impeller (3) and the inner impeller (207) are opposite.