A micro centrifugal pump and a method for manufacturing the same

Abstract

A micro centrifugal pump and a manufacturing method thereof. The pump includes a stator assembly, which includes an annular stator core, a coil frame fixed to the stator core, and a coil wound on the coil frame. The outer side surface of the stator core is provided with a positioning portion for positioning the stator assembly in the rotation direction of the mold during the first injection molding. The manufacturing method includes the following steps: firstly, the stator assembly is subjected to a first injection molding to form a plastic shell that seals the coil, the outer surface of the plastic shell forms a support portion that provides axial support for the mold during the second injection molding, and the positioning portion, pole arc surface and tooth end surface of the core are exposed to the plastic shell; then, the assembly after the first injection molding is subjected to a second plastic molding to form a pump body; wherein the pump body includes a rotor barrel covered on the pole arc surface and the tooth end surface after injection molding. This design reduces the installation process of the pump, enhances the connection strength between the pump body and the stator assembly, and improves the stability of the pump.

Description

Technical Field

[0001] The present invention relates to a miniature centrifugal pump belonging to a shielded pump, and in particular to a pump body structure of the centrifugal pump manufactured by plastic sealing. The IPC classification of the miniature centrifugal pump belongs to F04D 13 / 06 (2006.01). Background Art

[0002] The structure of the brushless motor-driven micro centrifugal pump commonly seen on the market is described in the prior patent with publication number CN208939684U. The motor stator of the pump includes a motor stator assembly and a plastic package, and the coil and circuit board on the motor stator assembly are plastic-sealed in the plastic package. Since the pump body is fixed to the motor stator by mold injection, corresponding positioning needs to be designed, but there is no good solution to this kind of annular stator injection pump body. The pump body is often made into a separate component and fixed to the motor stator by a buckle or screw connection. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for manufacturing the micro centrifugal pump, which reduces the installation process of the pump body, enhances the connection strength between the pump body and the stator assembly, the installation accuracy and the stability of the pump.

[0004] The technical solution adopted by the present invention is:

[0005] A method for manufacturing a micro centrifugal pump, the pump comprising a stator assembly, the assembly comprising an annular stator core, a coil frame fixed to the stator core, and a coil wound on the coil frame, characterized in that the method comprises the following steps:

[0006] 1) The outer cylindrical surface of the stator core is used to provide a positioning part for the mold to prevent the stator assembly from rotating during the primary injection molding. The stator assembly is subjected to primary injection molding to form a plastic shell that seals the coil. The outer surface of the plastic shell forms an axial support and a support part for the mold during the secondary injection molding. The positioning part, the pole arc surface and the tooth end surface of the stator core are exposed in the plastic shell;

[0007] 2) The components after the primary injection molding are subjected to secondary injection molding to form a pump body; the pump body includes a rotor cylinder covered on the pole arc surface and the tooth end surface after injection molding.

[0008] The stator assembly of this design is pressed and positioned by the mold through the positioning part of the core and the end face of the tooth part during the first injection molding, and a plastic shell with a supporting part is formed after the first injection molding. Then, the supporting part on the component after the first injection molding provides axial support to the mold during the second injection molding, so that the pump body can be injection molded on the component after the first injection molding.

[0009] During the primary injection molding, a support portion is formed on the plastic shell, which provides axial support for the secondary injection mold, allowing the primary injection molded component to be axially placed in the secondary injection mold for injection molding, forming a pump body fastened to the component. The centrifugal pump of this design has a simple structure and plays a positive role in simplifying the mold structure.

[0010] Furthermore, the plastic package shell also includes an annular body whose axial projection is annular, and the inner ring of the annular body is connected to the rotor cylinder.

[0011] Furthermore, the axial end surface of the plastic package shell protrudes with multiple shell bosses with axial projection in a fan-shaped shape, and a material transfer channel for the secondary injection plastic to flow is formed between adjacent shell bosses, and the annular body covers the shell bosses.

[0012] Furthermore, a pump body boss protrudes from the axial surface of the annular body, and the boss includes a first annular boss close to the axis and a second annular boss away from the axis, and the first boss and the second boss are transitionally connected via a conical surface.

[0013] Furthermore, the supporting portion is a plastic encapsulation boss radially extending from the outer surface of the plastic encapsulation shell.

[0014] Furthermore, the plastic sealing boss is provided with an axial hole or a notch for positioning during secondary injection molding.

[0015] Furthermore, on a plane perpendicular to the axis, a radial distance from the pole arc surface to the inner cylindrical surface of the plastic package shell is greater than 0.5 mm.

[0016] Furthermore, the positioning portion is a radial inner groove or an outer boss provided on the outer cylindrical surface of the stator core.

[0017] Furthermore, the coil frame is provided with a connecting terminal, and during secondary injection molding, the connection between the connecting terminal and the winding lead of the coil is sealed in the supporting part.

[0018] Furthermore, the pump body also includes an outer isolation layer covering the outer surface of the positioning portion.

[0019] In order to solve the above problems, the present invention also provides a micro centrifugal pump.

[0020] A micro centrifugal pump comprises a stator plastic sealing part, a pump body, a pump cover and a rotor assembly:

[0021] The stator plastic sealing part includes a stator assembly and a plastic sealing shell injection-molded on the surface of the stator assembly, the outer surface of the plastic sealing shell is provided with a support part, the stator assembly includes a coil frame fixed to the annular stator core and a coil wound on the coil frame, the coil is sealed in the plastic sealing shell, the outer cylindrical surface of the stator core is provided with a positioning part, and the positioning part, the pole arc surface and the tooth end surface of the stator core are exposed to the plastic sealing shell;

[0022] The pump body is formed by injection molding with the stator plastic sealing part as an insert, and comprises a rotor cylinder which is injection molded to cover the pole arc surface and the end surface of the tooth portion, and the inner hole of the cylinder is provided with a rotor cavity for accommodating the rotor assembly.

[0023] Furthermore, the supporting portion is a plastic sealing boss radially protruding from the outer surface of the sealing shell.

[0024] Furthermore, the plastic sealing boss is provided with an axial hole or a notch used for injection molding positioning.

[0025] Furthermore, the stator assembly is provided with a connection terminal for connection on the coil frame, and the connection portion between the winding lead of the coil and the terminal is injection molded on the first support part of the support parts.

[0026] Furthermore, the pump body also includes an outer isolation layer covering the surface of the positioning portion.

[0027] Furthermore, the supporting portion further includes a lug radially extending from the outer surface of the plastic package shell.

[0028] Furthermore, the open end of the rotor cylinder is provided with an annular body for assembling with the pump cover, and the inner ring of the annular body is connected to the rotor cylinder.

[0029] Furthermore, the axial end face protrusion of the plastic package shell is axially projected into a sector-shaped shell boss, and a material transfer channel for plastic flow during secondary injection molding is formed between adjacent shell bosses, and the annular body covers the shell boss.

[0030] Furthermore, a pump body boss protrudes from the axial end surface of the annular body, and the boss includes a first annular boss close to the axis and a second annular boss away from the axis, and the two bosses are transitionally connected by a conical surface.

[0031] Furthermore, the positioning portion is a radial outer groove or outer boss provided on the outer cylindrical surface of the stator core.

[0032] Furthermore, the pole arc surface of the stator core is provided with an inner groove for plastic to flow when the rotor cylinder is shaped, so that a thin isolation layer is formed on the pole arc surface of the rotor cylinder.

[0033] Furthermore, the thickness of the isolation layer is 0.2-0.8 mm.

[0034] Furthermore, the rotor cylinder is provided with axial ribs on the outer wall surface protruding from the bottom end surface of the plastic package shell.

[0035] Furthermore, the plastic shell is provided with a raised annular rib on the end surface facing away from the opening direction of the rotor cylinder, and the annular rib is coaxial with the rotor cylinder.

[0036] Furthermore, on a plane perpendicular to the axis, a radial distance from the pole arc surface to the inner annular surface of the plastic package shell is greater than 0.5 mm.

[0037] Furthermore, the outer side surface of the plastic package shell is provided with an inner arc surface which is concave radially inwards, and a screw column for installing a screw extends axially from the pump body at the arc surface.

[0038] The beneficial effects of the present invention can be reflected in the following aspects:

[0039] 1) The present invention utilizes the positioning portion and the tooth end face of the iron core to provide circumferential and axial positioning for the mold during the primary injection molding. After the injection molding, the plastic shell seals the coil inside to prevent the coil from being affected by the external environment, thereby improving the stability of the pump. The injection molding forms a supporting foundation for the secondary injection molding on the plastic shell. Furthermore, the pole arc surface of the iron core after the primary injection molding is exposed outside the plastic shell, which is beneficial to reduce the air gap between the stator core and the rotor assembly during the secondary injection molding of the pump housing. The design structure is simple and has a positive effect on simplifying the structure of the primary injection mold.

[0040] 2) The present invention utilizes the support portion on the plastic shell formed during the primary injection molding to provide axial support for the mold during the secondary injection molding. The stator assembly after the primary injection molding can be axially placed in the secondary injection molding mold through the support portion for injection molding to form a pump body portion fixed thereon. The design structure is simple and has a positive effect on simplifying the mold structure.

[0041] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic cross-sectional structure diagram of a centrifugal pump according to an embodiment of the present invention;

[0043] Figure 2 yes Figure 1 A is a schematic diagram of the partially enlarged structure of the middle part;

[0044] Figure 3 is a schematic structural diagram of a stator assembly according to an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the structure of a stator assembly after plastic sealing according to an embodiment of the present invention;

[0046] Figure 5 yes Figure 4 A top view of the stator plastic sealing part;

[0047] Figure 6 It is a schematic diagram of the structure of the stator plastic sealing part after the pump body is injection molded in an embodiment of the present invention;

[0048] Figure 7 yes Figure 6 Top view of the middle stator plastic sealing part after injection molding of the pump body;

[0049] Figure 8 It is a schematic diagram of the back structure of the stator plastic sealing part after the pump body is injection molded in an embodiment of the present invention;

[0050] Fig. 9 It is a schematic cross-sectional structure diagram of the stator plastic sealing part after the pump body is injection molded in the embodiment of the present invention;

[0051] Fig.10 It is a structural schematic diagram of the stator plastic sealing part of the second embodiment of the present invention;

[0052] Fig.11 yes Fig.10 A top view of the stator plastic sealing part;

[0053] Fig.12 It is a structural schematic diagram of a second embodiment of the present invention in which a notch is provided on the lug of the stator plastic sealing part;

[0054] Fig.13 1 is a schematic structural diagram of a stator plastic sealing portion of a third embodiment of the present invention;

[0055] Fig.14 yes Fig.13 Axial cross-sectional view of the stator plastic sealing part;

[0056] Fig.15 is a structural schematic diagram of a stator assembly in Embodiment 4 of the present invention;

[0057] Fig.16 It is a structural schematic diagram of a first implementation mode of a plastic-sealed boss after plastic sealing of a stator assembly in a fourth embodiment of the present invention;

[0058] Fig.17 yes Fig.16 Axial cross-sectional view of the stator plastic sealing part;

[0059] Fig.18 It is a structural schematic diagram of a second implementation mode of the plastic-sealed boss after the plastic-sealed stator assembly of the fourth embodiment of the present invention;

[0060] Fig.19 It is a structural schematic diagram of a fourth embodiment of the present invention in which a notch is provided on the plastic-sealed boss of the stator assembly after plastic sealing.

[0061] In the figure: 10-stator core 10.1-pole arc surface 10.2-tooth end surface 10.31-radial groove 10.4-inner groove 11-coil frame 12-coil 12.1-inner cylindrical surface of plastic shell 12.2-outer wall of plastic shell 12.21-outer side surface 13-connection terminal 14-connecting part 21.1-rotor cavity 21.2-isolating layer 21.3-impeller cavity 100-stator plastic shell 110-stator assembly 110′-stator assembly 120-plastic shell 121-support part 121′-support part 121″-support part 121″′-support part 121.1-first support part 121 .2-second lug 121.3-third lug 122-axial hole 122.1-first axial hole 122.2-second lug hole 122.3-third lug hole 123-feeding channel 124-annular rib 125-mounting hole 126-housing boss 127-notch 128-concave arc surface 200-pump body 210-rotor cylinder 220-annular body 220.1-inner ring 230-pump body boss 231-first annular boss 232-second annular boss 233-conical surface 240-convex rib 250-isolation layer 260-screw column 300-pump cover 400-rotor assembly 410-impeller DETAILED DESCRIPTION

[0062] The manufacturing method of the micro centrifugal pump of the embodiment of the present invention comprises a stator assembly 110, the assembly comprises an annular stator core 10, a coil frame 11 fixed to the annular stator core, and a coil 12 wound on the coil frame, and the manufacturing method comprises the following steps:

[0063] 1) The outer cylindrical surface of the stator core is used to provide a positioning part for the mold to prevent the stator assembly from rotating during the primary injection molding. The stator assembly 110 is subjected to primary injection molding to form a plastic package 120 that seals the coil 10. The outer surface of the plastic package 120 forms a support part 121 that provides axial support for the mold during the secondary injection molding. The positioning part, the pole arc surface 10.1 and the tooth end surface 10.2 of the core are exposed to the plastic package 120;

[0064] 2) The components after the primary injection molding are subjected to secondary injection molding to form a pump body 200; the pump body 200 includes a rotor cylinder 210 that covers the pole arc surface 10.1 and the end surface of the tooth portion 10.2 after injection molding.

[0065] The embodiment of the present invention uses the positioning part of the iron core and the end face of the tooth part to provide circumferential and axial positioning for the mold during the primary injection molding. After the injection molding, the plastic shell seals the coil inside to prevent the coil from being affected by the external environment, thereby improving the stability of the pump. After the primary injection molding, a support part is formed on the plastic shell, and the stator assembly after the primary injection molding is axially placed in the secondary injection molding mold through the support part for injection molding to form a pump body fixed thereon. The design structure is simple and has a positive effect on simplifying the mold structure.

[0066] Preferably, the pump body 200 further comprises an annular body 220 with an axial projection in an annular shape, and the inner ring 220.1 of the annular body is connected to the rotor barrel 210. After the annular body 220 of the pump body is connected to the pump cover 300, an impeller cavity 21.3 for accommodating the impeller 410 is formed. In order to enhance the connection strength of the pump body injection-molded on the stator assembly, the axial end face of the plastic package shell 120 protrudes a plurality of (6 in the figure) shell bosses 126 with an axial projection in a fan-shaped shape, and a radial material transfer channel 123 for the secondary injection-molded plastic to flow is formed between adjacent shell bosses, and the annular body 220 covers one axial side of the shell boss 126.

[0067] Preferably, a pump body boss 230 is raised on the axial end surface of the annular body 220, and the boss includes a first annular boss 231 close to the axis, a second annular boss 232 away from the axis, and a conical surface 233 transitionally connecting the first boss and the second boss. This design increases the contact area between water and the pump body, reduces the impact of water on the pump body when entering the impeller chamber, and reduces the vibration of the pump when it is working.

[0068] Preferably, the support portion 121 is a plastic encapsulation boss radially extending from the outer surface of the plastic encapsulation shell. The mold can use the plastic encapsulation boss to axially support the stator assembly after the primary molding in the mold for secondary injection molding. Its structure is simple and has a positive effect on simplifying the mold structure.

[0069] Furthermore, in order to prevent the stator assembly from rotating during the second injection molding and causing the pump body to deform during the injection molding, the plastic sealing boss is provided with an axial hole or notch for positioning.

[0070] Preferably, in order to enable the mold to clamp the stator assembly during one injection, the radial distance L1 from the pole arc surface 10.1 to the inner cylindrical surface 12.1 of the plastic package shell on a plane perpendicular to the axis is greater than 0.5 mm. In order to obtain a higher cost performance, the distance L1 for the mold to press should be 0.5 mm-1 mm.

[0071] Preferably, to facilitate the processing of parts, the positioning portion is a radial groove 10.31 or an outer convex ridge (not shown) provided on the outer cylindrical surface of the stator core.

[0072] Preferably, the coil frame 11 is provided with a connection terminal 13, and during the secondary injection molding, the connection between the connection terminal 13 and the winding lead of the coil 12 is sealed in the support portion 121. This design cleverly uses the plastic sealing boss that is molded outside the connection portion between the coil and the terminal as an axial support for the mold during the secondary injection molding. The mold uses the first support portion as an axial support to put the component after the primary injection molding into the mold of the secondary injection molding for injection molding production. Its structure is simple, which has a positive effect on simplifying the mold structure.

[0073] Preferably, in order to prevent water from penetrating from the positioning portion into the coil and damaging the coil, the pump body 200 includes an outer isolation layer 250 covering the surface of the positioning portion.

[0074] The structure of the micro centrifugal pump of the embodiment of the present invention is shown in Figures 1 to 5 . The micro centrifugal pump includes a stator plastic sealing part 100, a pump body 200, a pump cover 300 and a rotor assembly 400. The stator plastic sealing part 100 includes a stator assembly 110 and a plastic sealing shell 120 injection-molded on the surface of the stator assembly. The pump body 200 is formed by injection molding with the stator plastic sealing part 100 as an insert, and includes a rotor cylinder 210 and an annular body 220 for assembly with the pump cover 300. The rotor cylinder isolates the stator plastic sealing part 100 and forms a rotor cavity 21.1. The rotor assembly 400 is assembled in the rotor cavity 21.1. The pump cover 300 can be assembled on the pump body 200 by means of screws, snaps or welding. As one embodiment, see Figure 1 and Figure 5 A mounting hole 125 is provided on the end surface of the annular body 220, and the pump cover 300 is fixed thereto by screws.

[0075] The centrifugal pump uses the stator plastic sealing part as an injection molded insert, and the pump body is injection molded and fixed on the stator plastic sealing part. This design reduces the installation process of the pump, enhances the connection strength between the pump body and the stator assembly, and improves the stability of the pump.

[0076] See Figure 2 and 3 The stator assembly 110 includes an annular stator core 10, a coil frame 11 fixed on the core, and a coil 12 wound on the coil frame, and the outer cylindrical surface of the stator core 10 is provided with a positioning part. The stator plastic sealing part 100 is an injection-molded integrally formed component with a plastic sealing shell 120, which is formed by injection molding with the stator assembly 110 as an injection molding insert. After the stator assembly 110 is injected as above, the coil 11 is sealed in the plastic sealing shell 120, and the positioning part of the stator core, the pole arc surface 10.1 and the core tooth end face 10.2 connected to the pole arc surface and perpendicular to the axis are exposed to the plastic sealing shell 120. This design uses the tooth end face and the positioning part to provide circumferential and axial positioning for the mold. After injection molding, the plastic sealing shell seals the coil therein, which can prevent the coil from being affected by the external environment and improve the reliability of the pump. The sealing of the present invention is to form a plastic sealing shell that meets the housing protection level of IP54 for the coil after the injection molding of the designated subassembly.

[0077] See Figure 4 The plastic shell 120 includes an inner ring surface 12.1 of the plastic shell, an outer wall portion 12.2 of the plastic shell and a supporting portion 121 protruding from the outer surface, wherein the outer wall portion of the plastic shell includes an outer side surface and upper and lower end surfaces, and the inner ring surface of the plastic shell refers to the wall surface formed by the plastic shell in the inner ring of the stator assembly.

[0078] Preferably, see Figure 5 In a plane perpendicular to the axis, the radial distance L1 from the pole arc surface 10.1 to the inner annular surface 12.1 of the plastic package is greater than 0.5 mm. This design enables the mold to clamp the stator assembly during one injection molding. Furthermore, in order to obtain a higher cost-effectiveness, the value range of the distance L1 is 0.5 mm-1 mm.

[0079] See Figures 1 to 10 After the first injection molding, a support portion 121 is formed on the plastic shell 120 of the stator plastic sealing part. The positioning portion provides axial support for the mold during the second injection molding. During specific production, the stator plastic sealing part 100 after the first injection molding is placed in the mold for second injection molding to form the pump body part 200 with the rotor cylinder 210. The outer surface of the rotor cylinder 210 is fastened to the pole arc surface 10.1 and the tooth end face 10.2, and the stator core 10 and the inner annular surface 12.1 of the plastic sealing shell are isolated from the rotor cavity 21.1. This design can prevent the liquid in the rotor cavity 21.1 from penetrating into the stator assembly 110 and damaging the stator assembly 10. The design has a simple structure and has a positive effect on simplifying the mold structure of the first and second injection molding.

[0080] See Figure 3 The positioning portion is a radial groove 10.31 or an outer ridge (not shown) provided on the outer side surface of the stator core. This design prevents the stator assembly 110 from shifting in the mold cavity during the primary injection molding.

[0081] See Figure 3 , the pole arc surface 10.1 of the stator core is provided with an inner groove 10.4 on the bisector of the axial pole arc surface. During the secondary injection molding, the inner groove 10.4 allows the injection-molded plastic to flow more smoothly on the pole arc surface of the stator core, which is conducive to solving the problem of lack of glue in the rotor cylinder 210 injected on the pole arc surface 10.1. After this injection molding, the outer surface of the rotor cylinder 210 is embedded in the inner groove 10.4, and a thin isolation layer 21.2 is formed on the pole arc surface 10.1. In order to make the magnetic circuit air gap between the stator core and the rotor smaller and obtain higher electromagnetic efficiency, the thickness of the thin part of the isolation layer 21.2 is 0.2 to 0.8 mm. Among them, the inner surface of the rotor cylinder 210 to the pole arc surface 10.1 is the thin part, and the inner surface of the rotor cylinder 210 to the inner groove 10.4 is the thick part.

[0082] See Figure 4 and Figure 6 The outer side of the plastic package 120 is provided with an inner arc surface 128 which is concave radially inwards, and the pump body 200 axially extends a screw column 260 for installing a screw at the arc surface. This design facilitates the formation of the screw column during secondary injection molding without additionally widening the outer contour of the pump body, which has a positive effect on reducing the volume of the centrifugal pump and increasing the strength of the screw column.

[0083] See Figure 6or Figure 7 The pump body 200 further includes an isolation layer 250 covering the positioning portion, which covers the positioning portion to prevent water from penetrating from the positioning portion to the coil and damaging the coil, thereby achieving the purpose of increasing the life of the water pump. As a specific embodiment, the positioning portion is a radial groove 10.31 on the outer side of the stator core, and the isolation layer 250 covers the radial groove 10.31.

[0084] See Figure 1 , Figure 6 and Figure 7 The pump body 200 also includes an annular body 220 that is projected in an axial direction into a ring shape. The inner ring 220.1 of the annular body is connected to the rotor barrel 210, and after being connected to the pump cover 300, an impeller cavity 21.3 for accommodating an impeller is formed. In order to improve the connection strength of the pump body 200 injection-molded on the stator assembly, see Figure 1 and Figure 5 The axial end surface of the plastic package shell 120 protrudes a plurality of shell bosses 126 projected in a fan-shaped manner in the axial direction, and a material passage 123 is formed between adjacent shell bosses for plastic to flow during secondary injection molding. The annular body 220 covers one side of the axial direction of the shell boss 126, as shown in FIG. Figure 1 This design can use the annular body to separate the housing boss on the stator plastic sealing part from the impeller cavity, preventing the water in the impeller cavity from penetrating into the interior of the stator assembly along the housing boss and damaging the coil. Figure 5 , there are 6 housing bosses 126, the axial projection area of ​​each pump body boss is equal, and they are evenly distributed on the annular body 220. As other embodiments, the axial end face of the plastic package shell 120 may not be provided with a pump body boss, and the axial end face of the plastic package shell is a plane, and the annular body 220 of the pump body covers the end face. Or the axial end face of the plastic package shell 120 is an axially sunken groove on the above-mentioned plane, and the annular body 220 of the pump body covers the end face.

[0085] See Figure 6 and Fig. 9 A pump body boss 230 protrudes from the axial surface of the annular body 220. The pump body boss 230 includes a first annular boss 231 close to the axis, a second annular boss 232 away from the axis, and a conical surface 233 that transitionally connects the first boss and the second boss. This design increases the contact area between water and the pump body, reduces the impact of water on the pump body when entering the impeller chamber, and reduces the vibration of the pump when it is working.

[0086] See Figure 8 In the embodiment, the rotor cylinder 210 on the pump body is provided with an axial rib 240 on the outer wall surface protruding from the bottom end surface of the plastic package shell 120, and the rib prevents the rotor cylinder 210 from deforming after injection molding and improves the concentricity of the rotor cavity.

[0087] See Figure 8 The plastic case 120 of the embodiment is provided with a raised annular rib 124 on the end surface facing away from the opening direction of the rotor cylinder 210, and the rib is coaxial with the rotor cylinder. The annular rib 124 of the present invention prevents external liquid from flowing along the plastic case 120 to the junction of the plastic case 120 and the rotor cylinder 120, which has a positive effect on the waterproofing of the lift pump.

[0088] Embodiment 1:

[0089] See Figure 3 and Figure 4 The stator assembly 110 includes a terminal 13 disposed on the coil frame, and the connection portion between the winding lead of the coil and the terminal is injection molded on the first support portion 121.1 in the support portion. This design cleverly uses the plastic sealing boss that is injection molded on the outer protrusion of the connection portion between the coil and the terminal for axial support of the mold during secondary injection molding. The mold uses the first support portion as an axial support to place the component after primary injection molding into the mold of secondary injection molding for injection molding production. Its structure is simple and has a positive effect on simplifying the mold structure.

[0090] Preferably, a first axial hole 122.1 is provided on the axial end face of the first positioning portion 121.1. This design provides positioning for the mold during secondary injection molding, prevents the stator assembly from moving in the mold, and improves the molding qualification rate of the product.

[0091] Embodiment 2:

[0092] See Fig.10 and 11 Compared with Example 1, the difference between this embodiment and Example 1 is that the support portion 121 includes, in addition to the first support portion 121.1, a second lug 121.2 and a third lug 121.3 fixed to the outer cylindrical surface of the plastic package shell 120. This design allows the stator plastic package portion to be placed in a more balanced manner in the secondary injection mold. Furthermore, in order to prevent the stator assembly from moving in the mold, a second lug hole 122.2 and a third lug hole 122.3 are provided on the second lug 121.2 and the third lug 121.3, or a second lug 121.2 and a third lug 121.3 are provided as follows: Fig.12 The second convex notch 122.4 and the third lug hole 122.5 are shown. When the pump body 200 is injection molded, the positioning portion 121 and the shaft hole 122 are used for injection molding positioning. This design uses the location of the plastic-encapsulated terminal 13 on the plastic-encapsulated shell 120 as one of the three positionings for the injection molding of the pump body. This design does not require additional lugs to be added to the plastic-encapsulated shell 120, which saves injection molding materials.

[0093] Embodiment three:

[0094] See Fig.13 and 14The difference between this embodiment and embodiment 1 is that the support portion 121′ in this embodiment is a plastic encapsulation boss protruding from the outer cylindrical surface 12.21 of the plastic encapsulation shell. Fig.13 The plastic sealing boss is in the shape of a ring column protruding from the outer cylindrical surface 12.21 of the plastic sealing shell. During the secondary injection molding, the ring column is used to provide axial support for the mold.

[0095] Embodiment 4:

[0096] See Figures 15 to 17 The coils on the stator assembly 110' can be connected in a star or triangle connection after being stripped of paint, or a control board can be provided on the coils and connected using the control board. After injection molding of the stator assembly 110' of this structure, the outer cylindrical surface of the plastic package shell 120 does not need to protrude the first support part 121.1 for sealing the terminal. After one injection molding, the support part 121" structure is shown in FIG. Fig.16 The supporting portion 121″ is a plastic sealing boss protruding from the outer cylindrical surface of the plastic sealing shell 120. As a specific implementation of the plastic sealing boss of this embodiment, the plastic sealing boss is an annular column protruding from the outer cylindrical surface 12.21 of the plastic sealing shell. During the secondary injection molding, the annular column is used for axial support of the mold. As a second embodiment of the plastic sealing boss, the plastic sealing boss is a columnar body with an axial projection of a rectangle, and the number of the plastic sealing boss is at least 2. See Fig.18 In this embodiment, the number of plastic bosses is three. This design can reduce the outer contour size of the centrifugal pump and has a positive effect on reducing the volume of the pump. As another embodiment, the axial projection of the plastic boss can be a columnar body with a geometric shape such as a circle, a triangle, etc. Furthermore, in order to prevent the stator assembly from rotating during the second injection molding and causing the pump body to deform during the injection molding, an axial hole 122 for positioning is also provided on the plastic boss (see Fig.18 ) or gap 127 (see Fig.19 ).

[0097] The invention provides a micro centrifugal pump and a manufacturing method thereof, which solves the problem of injection molding a pump body on an annular stator assembly. The design structure is simple and has a positive effect on simplifying the mold structure.

[0098] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the above-mentioned embodiments do not depart from the spirit and scope of the present invention, such changes and modifications shall fall within the scope of the claims and equivalent technologies of the present invention.

Claims

1. A method for manufacturing a micro centrifugal pump, the pump comprising a stator assembly (110), the assembly comprising an annular stator core (10), a coil frame (11) fixed to the stator core (10), and a coil (12) wound on the coil frame, characterized in that: The method comprises the following steps: 1) The outer cylindrical surface of the stator core is used to provide a positioning portion for the mold to prevent the stator assembly from rotating during the primary injection molding. The stator assembly (110) is subjected to primary injection molding to form a plastic package (120) that seals the coil. The outer surface of the plastic package (120) forms a supporting portion (121) that is axially supported by the mold during the secondary injection molding. The positioning portion, the pole arc surface (10.1) and the end surface of the tooth portion (10.2) of the stator core (10) are exposed on the plastic package (120). The supporting portion (121) is a plastic package boss that radially extends from the outer surface of the plastic package. The positioning portion is a radial groove (10.31) or an outer convex ridge provided on the outer cylindrical surface of the stator core (10); 2) The components after the primary injection molding are subjected to secondary injection molding to form a pump body (200); the pump body (200) includes a rotor cylinder (210) which covers the pole arc surface and the tooth end surface after injection molding.

2. The manufacturing method according to claim 1, characterized in that: The plastic package shell (120) further comprises an annular body (220) having an annular shape in axial projection, wherein an inner ring (220.1) of the annular body (220) is connected to the rotor cylinder (210).

3. The manufacturing method according to claim 2, characterized in that: The axial end surface of the plastic package shell (120) protrudes a plurality of shell bosses (126) with an axial projection in a fan-shaped shape, and a material transfer channel (123) for secondary injection-molded plastic to flow is formed between adjacent shell bosses, and the annular body (220) covers the shell bosses (126).

4. The manufacturing method according to claim 2 or 3, characterized in that: A pump body boss (230) protrudes from the axial end surface of the annular body (220), and the boss comprises a first annular boss (231) close to the axis and a second annular boss (232) away from the axis. The first annular boss (231) and the second annular boss (232) are transitionally connected via a conical surface (233).

5. The manufacturing method according to claim 1, characterized in that: The plastic sealing boss is provided with an axial hole (122) or a notch (127) for positioning during secondary injection molding.

6. The manufacturing method according to claim 1, characterized in that: On a plane perpendicular to the axis, the radial distance from the pole arc surface (10.1) to the inner cylindrical surface (12.1) of the plastic package shell is greater than 0.5 mm.

7. The manufacturing method according to claim 1, characterized in that: The coil frame (11) is provided with a connection terminal (13), and during the secondary injection molding, the connection between the winding lead of the coil (12) and the connection terminal (13) is sealed in the support part (121).

8. The manufacturing method according to claim 1, characterized in that: The pump body (200) further comprises an outer isolation layer (250) covering the surface of the positioning portion.

9. A plastic-sealed micro centrifugal pump, comprising a stator plastic-sealed portion (100), a pump body portion (200), a pump cover (300) and a rotor assembly (400), characterized in that: The stator plastic sealing part (100) comprises a stator assembly (110) and a plastic sealing shell (120) injection-molded on the stator assembly, the outer surface of the shell is provided with a support part (121), the stator assembly (110) comprises a coil frame (11) fixed to an annular stator core and a coil (12) wound on the coil frame, the coil is sealed in the plastic sealing shell (120), the outer cylindrical surface of the stator core is provided with a positioning part, the positioning part, the pole arc surface (10.1) and the tooth part (10.2) end surface of the stator core are exposed to the plastic sealing shell, the support part (121) is a plastic sealing boss radially protruding on the outer surface of the plastic sealing shell, and the positioning part is a radial groove (10.31) or an outer convex ridge provided on the outer cylindrical surface of the stator core (10); The pump body (200) is formed by injection molding with the stator plastic sealing part (100) as an insert, and comprises a rotor cylinder (210) injection-molded over the pole arc surface (10.1) and the end surface of the tooth portion (10.2), wherein the inner hole of the cylinder is provided with a rotor cavity (21.1) for accommodating the rotor assembly.

10. The micro centrifugal pump according to claim 9, characterized in that: The plastic sealing boss is provided with an axial hole (122) or a notch (127) used for injection molding positioning.

11. The micro centrifugal pump according to claim 9, characterized in that: The stator assembly (110) is provided with a connection terminal (13) on the coil frame for connection, and the connection portion between the winding lead of the coil and the terminal is injection-molded on the first support part (121.1) of the support part (121).

12. The micro centrifugal pump according to claim 9 or 11, characterized in that: The pump body (200) further comprises an outer isolation layer (250) covering the surface of the positioning portion.

13. The micro centrifugal pump according to claim 11, characterized in that: The supporting portion (121) further comprises lugs (121.3, 121.2) radially extending from the outer peripheral surface of the plastic package shell.

14. The micro centrifugal pump according to claim 9, characterized in that: The open end of the rotor cylinder (210) is provided with an annular body (220) for assembling with a pump cover, and an inner ring (220.1) of the annular body is connected to the rotor cylinder (210).

15. The micro centrifugal pump according to claim 14, characterized in that: The axial end surface of the plastic package shell protrudes and is axially projected into a fan-shaped shell boss (126). A material transfer channel (123) for plastic to flow during secondary injection molding is formed between adjacent shell bosses. The annular body (220) covers the shell boss (126).

16. The micro centrifugal pump according to claim 14 or 15, characterized in that: A pump body boss (230) protrudes from the axial end surface of the annular body (220), and the boss comprises a first annular boss (231) close to the axis and a second annular boss (232) away from the axis. The first annular boss (231) and the second annular boss (232) are transitionally connected by a conical surface (233).

17. The micro centrifugal pump according to claim 9, characterized in that: The pole arc surface of the stator core is provided with an inner groove (10.4) for plastic to flow when the rotor cylinder is shaped, so that a thin isolation layer is formed on the pole arc surface of the rotor cylinder.

18. The micro centrifugal pump according to claim 17, characterized in that: The thickness of the isolation layer is 0.2-0.8 mm.

19. The micro centrifugal pump according to claim 9, characterized in that: The rotor cylinder (210) is provided with an axial convex rib (240) on the outer wall surface protruding from the bottom end surface of the plastic package shell.

20. The micro centrifugal pump according to claim 9 or 19, characterized in that: The plastic package shell is provided with a raised annular rib (124) on the end surface facing away from the opening direction of the rotor cylinder, and the annular rib is coaxial with the rotor cylinder.

21. The micro centrifugal pump according to claim 9, characterized in that: On a plane perpendicular to the axis, the radial distance from the pole arc surface (10.1) to the inner annular surface (12.1) of the plastic package shell is greater than 0.5 mm.

22. The micro centrifugal pump according to claim 9, characterized in that: The outer side surface of the plastic package shell (120) is provided with a radially concave inner arc surface (128), and a screw column (260) for installing screws axially extends out of the pump body (200) at the inner arc surface.

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