Plastic package pump body and centrifugal pump

Abstract

The plastic package pump body comprises a stator assembly and a plastic package shell, the stator assembly comprises an iron core formed by rolling a plurality of sequentially connected iron core units, a framework and a winding, an axial hole is formed in a yoke part of the iron core, the plastic package shell is arranged on the stator assembly in an injection molding mode and comprises an inner shell part, an upper end part, a lower end part and a connecting part, and the opening direction of the inner shell part is the same as that of the axial hole; the radial distance between the inner wall surface of the inner shell part and the pole cambered surface is not more than 1mm, the upper end part is provided with a first axial hole, and the lower end part is provided with a second axial hole or a notch. According to the plastic package pump body, the plastic package shell is provided with the first axial hole and the second axial hole or the notch for the positioning needle of the mold to penetrate through, and the axial hole located in the yoke portion provides supporting and positioning for the stator assembly placed in the mold after the iron core is rolled to be round, so that injection molding plastic can be directly, evenly and thinly attached to the pole cambered surface of the iron core of the stator assembly; the air gap is reduced, the electromagnetic performance is improved, and meanwhile the production qualification rate is considered.

Description

Technical Field

[0001] The invention relates to a plastic-sealed pump body and a centrifugal pump using the plastic-sealed pump body, and the IPC classification number of the pump body is F04D 13 / 06. Background Art

[0002] As shown in the patent publication number CN216056508U, the core of the stator assembly of the existing electric water pump is a strip-shaped iron core that is rolled into a round shape. During production, it is usually necessary to first perform an injection molding on the stator assembly to form a plastic-sealed stator assembly, and then perform an injection molding again to form a pump body including the stator assembly, or to assemble an independent pump body plastic part with the above-mentioned plastic-sealed stator assembly to form a pump body including the stator. The production process is numerous and time-consuming, resulting in low production efficiency.

[0003] Except as otherwise specified, the common knowledge and terms involved in this specification refer to the "Mechanical Engineering Handbook" and "Electrical Engineering Handbook" published by the Machinery Industry Press, first edition from 1978 to 1983 and second edition in 1997, "New Edition of Motor Winding Repair" published by Shanghai Science and Technology Press, first edition in 1995, and patent document CN216056508U. Summary of the invention

[0004] In order to solve the problems described in the background technology, the present invention provides the following technical solutions:

[0005] A plastic-sealed pump body, including a stator assembly and a plastic-sealed shell, the stator assembly including an iron core formed by rolling a plurality of sequentially connected iron core units, a frame fixed on the iron core, and a winding wound on the frame, characterized in that: the yoke of the iron core is provided with a plurality of blind hole-like axial holes formed by axial sinking, the plastic-sealed shell is formed by injection molding based on the stator assembly, including a cylindrical inner shell portion with an opening at one end covering the pole arc surface of the iron core, an upper end portion extending radially outward from the outer edge of the opening of the inner shell portion, a lower end portion extending radially outward from the center of the bottom of the inner shell portion, and a connecting portion connecting the upper and lower ends, the inner shell portion and the axial hole have the same opening direction, the radial distance from the inner wall surface of the inner shell portion to the pole arc surface is not greater than 1 mm, the upper end portion is provided with a first axial hole for an injection mold positioning piece to pass through and be inserted into the axial hole, and the lower end portion is provided with a second axial hole or notch for an injection mold positioning piece to pass through and abut against the stator assembly.

[0006] The plastic-sealed pump body of the present invention has a plastic shell designed with a first axial hole, a second axial hole or a notch for the positioning pin of the mold to pass through, and the axial hole located on the yoke after the iron core is rolled up provides support and positioning for the stator assembly placed in the mold, preventing the stator assembly from being offset by the impact of molten plastic during the injection molding of the plastic shell, so that the injection-molded plastic can be directly and evenly adhered to the pole arc surface of the iron core of the stator assembly, thereby reducing the air gap, improving the electromagnetic performance and taking into account the production qualification rate.

[0007] Furthermore, the axial hole is a circular hole, and its axis is evenly distributed on the same cylindrical surface. In the projection of the same axial plane, the axis of the cylindrical surface is concentric with the axis of the cylindrical surface where the polar arc surface is located. This design can ensure the concentricity of the cylindrical surface where the polar arc surface is located and the injection mold core through the concentric positioning of the axial hole, avoiding the uneven thickness of the thin wall of the injection molded inner shell or even the phenomenon of insufficient glue caused by the eccentricity of the mold core, so that a uniform thin layer of the inner shell can be formed during the injection molding of the plastic shell.

[0008] Furthermore, the yoke of the core unit provided with the axial hole protrudes radially outward to form an arc-shaped protrusion, and the axial hole is at least partially located on the protrusion.

[0009] Furthermore, the skeleton is formed by integral injection molding based on the iron core, and a radially outer surface of the skeleton is provided with a radially inwardly concave skeleton recess.

[0010] Furthermore, the plastic-sealed pump body also includes an adapter plate arranged on the axial side of the iron core and electrically connected to the winding, and a terminal fixed on the adapter plate. The adapter plate is wrapped in the plastic shell, and the plug-in piece of the terminal is exposed outside the plastic shell.

[0011] Furthermore, a lower end surface of the lower end portion is protruded to form a stepped boss that wraps around the outer side surface of the insulating base of the terminal.

[0012] Furthermore, an axial end surface of the lower end portion is provided with an axially protruding column-shaped guide column.

[0013] Furthermore, the plastic package shell also includes an annular outer shell portion located radially outside the connecting portion, the upper end portion, the outer shell portion, the connecting portion and the upper end portion form a cooling cavity, and the upper end surface of the upper end portion is provided with an axial through hole connecting the cooling cavity with the outside.

[0014] Furthermore, in the projection on the same axial plane, the axis center of the cylindrical surface where the yoke is located is concentric with the axis center of the cylindrical surface where the pole arc surface is located.

[0015] Furthermore, a columnar transition portion connecting the outer shell portion and the connecting portion is provided in the cooling cavity, and the transition portion divides the cooling cavity into a plurality of independent cooling channels.

[0016] Furthermore, the axial through hole connects two adjacent cooling channels.

[0017] A centrifugal pump comprises any one of the above-mentioned plastic-sealed pump bodies, a pump cover arranged on the plastic-sealed pump body, a rotor assembly with an impeller, a rotating shaft fixed on the inner shell of the plastic-sealed pump body, a rear end cover arranged on the side of the plastic-sealed pump body away from the impeller and forming a heat dissipation cavity with the plastic-sealed pump body, and a first plug fixed on the first axial hole. The rotor assembly is rotatably mounted on the rotor cavity surrounded by the cylindrical inner shell, the impeller is accommodated in the impeller cavity surrounded by the pump cover and the plastic-sealed pump body, and the impeller cavity and the heat dissipation cavity are conductively connected.

[0018] The centrifugal pump of the present invention has a rear end cover on the side of the pump body away from the impeller, so that the liquid in the impeller cavity can flow into the heat dissipation cavity to dissipate heat for the parts arranged axially outside the rear end cover. The design is simple, reliable and has high production efficiency.

[0019] Furthermore, a shaft through hole is provided in the axial direction of the shaft, and the shaft through hole connects the impeller cavity and the heat dissipation cavity.

[0020] Furthermore, the bottom of the inner shell portion is provided with an inner shell through hole for connecting the rotor cavity and the heat dissipation cavity.

[0021] Furthermore, the centrifugal pump also includes an end plate covered on the rear end cover and a circuit board accommodated in a receiving cavity surrounded by the rear end cover and the end plate.

[0022] The more specific design and technical effects of the present invention are further explained in the specific implementation manner in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of a plastic-sealed pump body of the present invention;

[0024] Figure 2 is a cross-sectional view of the plastic-sealed pump body of the present invention at the cutting plane A;

[0025] Figure 3 is a cross-sectional view of the plastic-sealed pump body of the present invention at the cutting plane B;

[0026] Figure 4 is a schematic diagram of the plastic-sealed pump body of the present invention from another angle;

[0027] Figure 5 is a schematic diagram of a stator assembly of the present invention;

[0028] Figure 6 is a top view of a stator assembly of the present invention;

[0029] Figure 7 is a schematic diagram of the iron core of the present invention before being rolled;

[0030] Figure 8 This is a schematic diagram of the iron core of the present invention after being rolled into a circle;

[0031] Fig. 9 is a schematic diagram of another embodiment of the plastic-sealed pump body of the present invention;

[0032] Fig.10 is a schematic diagram of a centrifugal pump of the present invention;

[0033] Fig.11 is an axial cross-sectional view of a centrifugal pump of the present invention;

[0034] Fig.12 is a schematic diagram of a first plug of the present invention;

[0035] Fig.13 is an axial cross-sectional view of a centrifugal pump according to a second embodiment of the present invention;

[0036] Among them: 1-stator cavity, 2-cooling cavity, 3-impeller cavity, 4-heat dissipation cavity, 5-accommodating cavity, 6-rotor cavity, 10-plastic sealed pump body, 11-cooling flow channel, 20-pump cover, 30-rotor assembly, 31-impeller, 32-main body, 33-permanent magnet, 40-rotating shaft, 41-rotating shaft through hole, 50-rear end cover, 61-first plug, 62-plug body, 63-plug protrusion, 65-second plug, 70-end plate, 80-circuit board, 100-stator assembly, 110-iron core, 111-core unit, 112-yoke, 113-axial hole, 11 4-protrusion, 115-arc surface, 116-tooth, 117-boot, 120-skeleton, 121-skeleton recess, 130-winding, 140-adapter, 150-terminal, 151-insert, 152-insulating base, 200-plastic shell, 210-inner shell, 211-inner shell through hole, 220-upper end, 221-first axial hole, 222-axial through hole, 230-lower end assembly, 231-second axial hole, 232-boss, 233-guide column, 234-notch, 240-connecting part, 250-outer shell, 260-transition part DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] As shown in the accompanying drawings, the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. When describing the structure of the present invention, the side where the pump water inlet is located is regarded as the upper side or upper end, and the opposite side is regarded as the lower side or lower end; the side adjacent to the rotation center of the motor is regarded as the inner side, and the opposite side is regarded as the outer side. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be understood as limiting the present invention.

[0039] See Figure 1 , Figure 2 and Figure 5The present invention discloses a plastic-sealed pump body 10, comprising a stator assembly 100 and a plastic-sealed shell 200 formed by injection molding with the stator assembly as an insert, wherein the stator assembly 100 comprises an iron core 110 formed by rolling a plurality of sequentially connected iron core units 111, a frame 120 fixed on the iron core 110, and a winding 130 wound on the frame 120.

[0040] See Figure 7 and Figure 8 The core unit 111 includes a yoke 112, a tooth 116 connected to the yoke 112, and a boot 117 formed by protruding to both sides at the end of the tooth. The surface of the boot 117 facing away from the yoke is an arc-shaped arc surface 115. Some core units 111 are sunken in the axial end surface of the yoke 112 to form a blind hole-like axial hole 113. Preferably, in order to provide uniform support for the stator assembly, there are at least three axial holes 113 and they are arranged equidistantly on the core 110.

[0041] See Figures 6 to 8 When each core unit 111 is rolled, the axial hole 113 on the core can be inserted and matched with the positioning pin on the rolling jig to facilitate the rolling connection of the core 110. In this embodiment, six blind hole-shaped axial holes 113 are provided on the core yoke 112. After rolling, the axis D1 of each axial hole 113 is evenly distributed on the same cylindrical surface K1, and the axis a1 of the cylindrical surface K1 is concentric with the projection of the axis a2 of the cylindrical surface where the pole arc surface 115 is located on the same axial plane. Through the above design, when the stator assembly is placed in the mold, the axial hole can concentrically position the stator assembly with the mold cavity and the mold core, so that a uniform thin layer of inner shell can be formed on the inner side of the pole arc surface during injection molding of the plastic shell. Furthermore, the core 110 protrudes radially outward from the center of the yoke 112 of the core unit 111 provided with the axial hole 113 to form an arc-shaped protrusion 114, and the axial hole 113 is at least partially located in the protrusion 114. Preferably, the arc of the protrusion 114 is concentric with the axial hole 113. The design of the arc-shaped protrusion 114 can ensure that the frame 120 can be fixed on the core 110 while reducing the volume of the core 110.

[0042] See Figures 2 to 4In order to improve production efficiency, the plastic package 200 of the present invention is directly injection-molded with the above-mentioned stator assembly 100 as an insert and fixed on the stator assembly 100. The plastic package 200 includes a cylindrical inner shell 210 covering the pole arc surface 115 of the iron core 110, an upper end 220 extending radially outward from the upper end opening of the inner shell 210 to cover the skeleton 120 and the winding 130, a lower end 230 extending outward from the center of the bottom of the inner shell to cover the skeleton 120 and the winding 130, and a The upper end 220 and the lower end 230 are connected to the connecting portion 240 covering the outer periphery of the core 110. To facilitate the mold opening and provide support and positioning for the stator assembly 100 axially placed in the mold, the opening direction of the inner shell 210 is the same as the opening direction of the axial hole 113. The upper end 220 is provided with a first axial hole 221 for the injection mold positioning piece to pass through and insert into the axial hole 113, and the lower end 230 is provided with a positioning structure for the injection mold positioning piece to pass through and abut against the stator assembly 100. Preferably, the radial distance H from the inner wall surface of the inner shell 210 to the pole arc surface 115 is not greater than 1 mm, and the stator assembly 100 is covered and accommodated in the stator cavity 1 surrounded by the inner shell 210, the upper end 220, the lower end 230 and the connecting portion 240. Preferably, the radial distance H from the inner wall surface of the inner shell 210 to the pole arc surface 115 is 0.5-1 mm.

[0043] See Figure 4 As a preferred embodiment, the lower end portion 230 of the present invention is provided with a positioning structure for the injection mold positioning piece to pass through and abut against the stator assembly 100. Specifically, a second axial hole 231 is provided on the axial plane of the lower end portion 230 for the injection mold positioning piece to pass through and abut against the stator assembly 100. During injection molding, the positioning piece of the mold passes through the second axial hole 231 and abuts against the stator assembly 100 to provide positioning and support for it. Of course, as other embodiments, see Fig. 9 The lower end portion 230 may be provided with a positioning structure for the injection mold positioning piece to pass through and abut against the stator assembly 100. A notch 234 may be provided on the axial plane of the lower end portion 230 for the injection mold positioning piece to pass through and abut against the iron core 100. When the plastic shell is injection molded, the positioning piece of the mold passes through the notch 234 at the lower end and abuts against the iron core, providing positioning and support for the stator assembly 100.

[0044] See Figure 5In order to facilitate the connection of windings of the same phase, as a preferred embodiment of the stator assembly 100, the stator assembly 100 further includes an adapter plate 140 disposed on the axial side of the iron core 110 and electrically connected to the winding 130, and a terminal 150 fixed on the adapter plate 140. The terminal 150 includes an insulating base 152 and an insert fixed on the insulating base 152. After the stator assembly of this embodiment is injection molded, the adapter plate 140 is accommodated in the stator cavity 1, and the insert 151 is at least partially exposed to the plastic shell 200. Further, as Figure 5 and Figure 6 The skeleton 120 of the present invention is fixed on the iron core 110 by injection molding, and its radial outer surface is provided with a radially concave skeleton recess 121. Through the above design, the skeleton 120 can be reduced from being crushed by the melted plastic when the plastic package 200 is injection molded. Of course, as other embodiments, the skeleton can also adopt a first skeleton and a second skeleton respectively arranged on both sides of the iron core, which are installed on the iron core after being spliced.

[0045] Further, see Figure 4 The axial end surface of the lower end portion 230 of the plastic package of the present invention protrudes a stepped boss 232, which wraps the outer side surface of the insulating base 152 of the terminal 150, thereby reducing the risk of external liquid penetrating into the stator cavity from the junction between the terminal and the plastic package and causing a short circuit in the stator assembly, thereby improving the working safety of the plastic package pump body. Figure 4 In order to facilitate the assembly of the plastic-sealed pump body and external parts, the axial end surface of the lower end portion 230 of the plastic-sealed shell of the present invention is provided with an axially protruding columnar guide column 233.

[0046] See Figures 2 to 4As a preferred embodiment, the plastic-encapsulated shell 200 of the plastic-encapsulated pump body of the present invention further includes an annular outer shell portion 250 located radially outside the connecting portion 240, and the inner side surface of the outer shell portion 250, the axial end surface of the upper end portion 220, and the outer side surface of the connecting portion 240 form a cooling cavity 2. To facilitate the introduction of liquid into the cooling cavity 2, an axial through hole 222 is provided on the axial end surface of the upper end portion 220 to connect the cooling cavity 2 with the outside. Furthermore, in the present embodiment, the axis a1 of the cylindrical axial hole 113 is concentric with the axis a2 of the cylindrical surface where the pole arc surface 115 is located and the axis a3 of the cylindrical surface where the yoke 112 is located in the projection on the same axial plane. This design ensures that when the plastic-encapsulated shell with an outer shell is produced by injection molding, the design of the axial hole can ensure the concentricity of the axis of the cylindrical surface where the pole arc surface is located and the cylindrical surface where the yoke is located with the injection mold core projected on the same axial plane, so as to provide accurate and stable positioning of the stator assembly in the mold, so that the injection molded plastic can evenly cover the radial outer surface of the yoke of the core and the pole arc surface of the core, reducing the risk of glue shortage during injection molding. Furthermore, the plastic-encapsulated pump body of the present invention is provided with a transition portion 260 connecting the outer shell 250 and the connecting portion 240 in the cooling chamber 2. The transition portion 260 divides the cooling chamber 2 into a plurality of cooling channels 11, so that the liquid in the impeller chamber can quickly pass through the cooling channels, thereby improving the heat dissipation effect of the centrifugal pump. See Figure 1 and Figure 4 The axial through hole 222 connects two adjacent cooling channels 11. This structure can reduce the turbulence of water flowing through the cooling channel, so that the water can flow smoothly into and through the cooling channel, thereby improving the heat dissipation effect of the centrifugal pump.

[0047] See Figures 10 to 12The present invention also discloses a centrifugal pump, comprising the above-mentioned plastic-sealed pump body 10, a pump cover 20 covered on the plastic-sealed pump body, a rotor assembly 30, a rotating shaft 40 fixed on the inner shell 210 of the plastic-sealed pump body, a rear end cover 50 covered on the side of the plastic-sealed pump body 10 away from the impeller 31, a first plug 61 fixed on the first axial hole 221, and a second plug 65 fixed on the second axial hole 231. The rotor assembly 30 comprises a main body 32, a permanent magnet 33 fixed on the main body 32, and an impeller 31 located on one axial side of the main body 32, the impeller 31 is accommodated in an impeller cavity 3 surrounded by the pump cover 20 and the plastic-sealed pump body 10, and the rotor assembly 30 is rotatably mounted on the rotor cavity 6 surrounded by the cylindrical inner shell 210. The first plug 61 includes a columnar plug body 62 and a plug protrusion 63 protruding from the axial end face of the plug body 62, and the second plug 65 has a structure similar to the first plug 61. After the rear end cover 50 of the present invention is covered on the plastic-sealed pump body 10, the rear end cover 50 and the plastic-sealed pump body 10 enclose a heat dissipation chamber 4, wherein the impeller chamber 3 and the heat dissipation chamber 4 are connected, so that the liquid in the impeller chamber 3 can enter the heat dissipation chamber 4 to dissipate the heat of the parts arranged on the axial outside of the rear end cover 50. The centrifugal pump of the present invention improves its electromagnetic performance and has high production efficiency by optimizing the design of the plastic-sealed pump body. Of course, as other embodiments, when the positioning structure is a lower end notch arranged at the lower end, the centrifugal pump can omit the second plug and can also achieve the effect of the above-mentioned whole pump structure.

[0048] See Fig.11 As a specific embodiment of the present invention, the impeller chamber 3 and the heat dissipation chamber 4 are connected in a specific manner that a shaft through hole 41 is provided in the axial direction of the shaft 40, and the shaft through hole 41 connects the impeller chamber 3 and the heat dissipation chamber 4. The above design can reduce the interference of the liquid on the rotation of the rotor assembly when the liquid flows between the heat dissipation chamber and the impeller chamber, and improve the working stability of the centrifugal pump. Of course, as other embodiments, an axial through hole can be provided on the axial bottom surface of the inner shell 210 to achieve the conductive connection between the impeller chamber 3 and the heat dissipation chamber 4. See Figure 4 and Fig.11 In order to increase the flow rate of the liquid flowing through the heat dissipation cavity and further improve the heat dissipation effect of the centrifugal pump, as a preferred embodiment, the bottom of the inner shell 210 is provided with an inner shell through hole 211 that connects the rotor cavity and the heat dissipation cavity 4.

[0049] See Fig.11 The centrifugal pump of the present invention further comprises an end plate 70 covered on the rear end cover 50 and a circuit board 80 accommodated in the accommodation cavity 5 surrounded by the rear end cover 50 and the end plate 70. This design can utilize the liquid in the heat dissipation cavity to dissipate the heat of the circuit board, thereby avoiding the situation where the heat dissipation plate is burned due to overheating, and further improving the working stability of the centrifugal pump.

[0050] See Fig.11The working principle of the centrifugal pump of the present invention is as follows: when the centrifugal pump is working, the impeller 31 rotates, and a part of the liquid in the impeller cavity 3 is discharged outward through the pump cover 20; the other part of the liquid passes through the rotor cavity 6 and the inner shell through hole 211, and passes through the axial through hole 222 and the cooling cavity 2 to flow into the heat dissipation cavity 4, and the liquid collected in the heat dissipation cavity 4 flows back to the impeller cavity 2 through the shaft through hole 41, and the liquid completes the heat dissipation of the stator assembly and the circuit board arranged on the axial outside of the rear end cover during the above-mentioned flow channel process. Of course, as other embodiments, the inner shell part of the plastic shell of the centrifugal pump may not be provided with an inner shell through hole. The working principle of the centrifugal pump is as follows: the liquid in the impeller cavity passes through the axial through hole into the cooling cavity and then flows into the heat dissipation cavity, and the liquid in the heat dissipation cavity flows back to the impeller cavity through the shaft through hole, and the heat dissipation of the circuit board arranged on the axial outside of the rear end cover can also be achieved. Fig.13 It is a cross-sectional view of another embodiment of the centrifugal pump of the present invention. The difference between it and the above centrifugal pump is that the plastic-sealed shell 200 of the plastic-sealed pump body does not have an outer shell portion arranged outside the connecting portion. The working principle of the centrifugal pump of this embodiment is as follows: when the centrifugal pump is working, the impeller 31 rotates, and a part of the liquid in the impeller cavity 3 is discharged outward through the pump cover 20; the other part of the liquid passes through the shaft through hole 41 to enter the heat dissipation cavity 4 to dissipate heat to the circuit board arranged axially outside the rear end cover.

[0051] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims and equivalent technologies of the present invention, the present invention is also intended to include these changes and modifications.

Claims

1. A plastic-encapsulated pump body, comprising a stator assembly (100) and a plastic-encapsulated shell (200), wherein the stator assembly (100) comprises an iron core (110) formed by rolling a plurality of sequentially connected iron core units (111), a frame (120) fixed on the iron core (110), and a winding (130) wound on the frame (120), characterized in that The yoke (112) of the iron core (110) is provided with a plurality of blind hole-shaped axial holes (113) formed by axially sinking. The plastic package shell (200) is formed by injection molding based on the stator assembly (100), and comprises a cylindrical inner shell (210) with an opening at one end covering the pole arc surface (115) of the iron core (110), an upper end (220) extending radially outward from the outer edge of the opening of the inner shell (210), a lower end (230) extending radially outward from the center of the bottom of the inner shell, and a connecting member connecting the upper and lower ends. The inner shell portion (210) and the axial hole (113) are connected to each other, the inner shell portion (210) and the axial hole (113) have the same opening direction, the radial distance from the inner wall surface of the inner shell portion (210) to the pole arc surface (115) is not greater than 1 mm, the upper end portion (220) is provided with a first axial hole (221) for the injection mold positioning piece to pass through and be inserted into the axial hole (113), and the lower end portion (230) is provided with a second axial hole (231) or a notch (234) for the injection mold positioning piece to pass through and abut against the stator assembly (100).

2. The plastic-sealed pump body according to claim 1, characterized in that: The axial hole (113) is a circular hole, the axis of which is evenly distributed on the same cylindrical surface. In the projection of the same axial plane, the axis of the cylindrical surface is concentric with the axis of the cylindrical surface where the polar arc surface (115) is located.

3. The plastic-sealed pump body according to claim 1 or 2, characterized in that: The yoke (112) of the core unit (111) provided with the axial hole (113) protrudes radially outward to form an arc-shaped protrusion (114), and the axial hole (113) is at least partially located on the protrusion (114).

4. The plastic-sealed pump body according to claim 1, characterized in that: The skeleton (120) is formed by integral injection molding based on the iron core (110), and a radially outer surface thereof is provided with a radially inwardly concave skeleton recess (121).

5. The plastic-sealed pump body according to claim 1, characterized in that: It also includes an adapter plate (140) arranged on an axial side of the iron core (110) and electrically connected to the winding (130), and a terminal (150) fixed on the adapter plate (140), wherein the adapter plate (140) is wrapped in a plastic package (200), and an insert (151) of the terminal (150) is exposed outside the plastic package (200).

6. The plastic-sealed pump body according to claim 5, characterized in that: The lower end surface of the lower end portion (230) is protruded to form a stepped boss (232) that wraps around the outer side surface of the insulating base (152) of the terminal.

7. The plastic-sealed pump body according to claim 5 or 6, characterized in that: The axial end surface of the lower end portion (230) is provided with an axially protruding columnar guide column (233).

8. The plastic-sealed pump body according to claim 1 or 2, characterized in that: The plastic package shell (200) further comprises an annular outer shell portion (250) located radially outside the connecting portion (240); the upper end portion (220), the outer shell portion (250), the connecting portion (240) and the upper end portion (220) enclose a cooling cavity (2); and an upper end surface of the upper end portion (220) is provided with an axial through hole (222) for connecting the cooling cavity (2) with the outside.

9. The plastic-sealed pump body according to claim 8, characterized in that: In the projection on the same axial plane, the axis center of the cylindrical surface where the yoke (112) is located is concentric with the axis center of the cylindrical surface where the pole arc surface (115) is located.

10. The plastic-sealed pump body according to claim 8, characterized in that: A columnar transition portion (260) is provided in the cooling cavity (2) to connect the outer shell portion (250) and the connection portion (240), and the transition portion (260) divides the cooling cavity (2) into a plurality of independent cooling channels (11).

11. The plastic-sealed pump body according to claim 10, characterized in that: The axial through hole (222) connects two adjacent cooling channels (11).

12. A centrifugal pump, characterized in that: The invention comprises a plastic-sealed pump body (10) as claimed in any one of claims 1 to 11, a pump cover (20) arranged on the plastic-sealed pump body, a rotor assembly (30) with an impeller (31), a rotating shaft (40) fixed on the inner shell (210) of the plastic-sealed pump body, a rear end cover (50) arranged on the side of the plastic-sealed pump body (10) away from the impeller (31) and forming a heat dissipation cavity (4) with the plastic-sealed pump body (10), and a first plug (61) fixed on the first axial hole (221), wherein the rotor assembly (30) is rotatably mounted on the rotor cavity (6) formed by the cylindrical inner shell (210), the impeller (31) is accommodated in the impeller cavity (3) formed by the pump cover (20) and the plastic-sealed pump body (10), and the impeller cavity (3) and the heat dissipation cavity (4) are conductively connected.

13. The centrifugal pump according to claim 12, characterized in that: A rotating shaft through hole (41) is provided in the axial direction of the rotating shaft (40), and the rotating shaft through hole (41) connects the impeller chamber (3) and the heat dissipation chamber (4).

14. The centrifugal pump according to claim 12 or 13, characterized in that: The bottom of the inner shell portion (210) is provided with an inner shell through hole (211) for connecting the rotor cavity (6) and the heat dissipation cavity (4).

15. The centrifugal pump according to claim 12 or 13, characterized in that: It also includes an end plate (70) covered on the rear end cover (50) and a circuit board (80) accommodated in an accommodation cavity (5) surrounded by the rear end cover (50) and the end plate (70).

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