Screw pump stator end face structure and stator forming die

Abstract

The application discloses a screw pump stator end face structure and a stator forming die. The end face structure comprises a metal sleeve provided with a through hole in the axial direction; a rubber bushing adhered in the through hole, an internal core arranged in the rubber bushing, and clamping portions of the rubber bushing extending out of the through hole and clamping two side end faces of the metal sleeve respectively; both side end faces of the rubber bushing are provided with an outer ring boss, and the rubber bushing is provided with a concave surface in the inner ring area of the outer ring boss, and the port of the internal core is arranged in the concave surface. Since a gradient structure is formed between the outer ring boss and the concave surface, the deformation of the outer ring boss under pressure is difficult to be transmitted to the inner ring area where the concave surface is located, so that the deformation of the internal core due to extrusion is effectively avoided, and the cooperation precision of the internal core and the rotor is ensured. Meanwhile, the arrangement of the outer ring boss enables the port of the internal core to be separated from the shell, and the damage of the port of the internal core due to friction with the shell is avoided.

Description

Technical Field

[0001] This invention relates to the technical field of screw pumps, and particularly to the stator end face structure of screw pumps and stator forming molds. Background Technology

[0002] The stator of a screw pump is one of its core components. Its structure typically includes a steel sleeve and a rubber bushing. The rubber bushing contains an internal core that mates with the rotor; together, they form a sealed chamber for fluid intake and discharge. To lock the relative position of the rubber bushing and the steel sleeve and prevent the rubber bushing from axially dislodging from the steel sleeve, in existing technology, the rubber bushing typically extends to both end faces of the steel sleeve and fully covers the end faces of the steel sleeve, ensuring the stability of the connection.

[0003] During actual installation and use, the stator needs to be assembled with the housing. During assembly, the outer ring of the rubber bushing end face will be squeezed by the housing. This squeezing action achieves a sealed connection between the stator and the housing, ensuring the sealing performance of the screw pump during operation and preventing fluid leakage.

[0004] However, existing screw pump stator rubber bushings have the following problems during use: when the outer ring of the rubber bushing end face is squeezed by the outer shell, the squeezing force is directly transmitted to the inner ring of the end face, causing deformation of the internal core of the rubber bushing. This deformation of the internal core compromises the fit accuracy with the rotor, affecting the screw pump's delivery efficiency and operational stability. Summary of the Invention

[0005] The present invention aims to provide a stator end face structure for a screw pump to solve the technical problem that the internal core of the rubber bushing is prone to deformation.

[0006] According to a first aspect of the present invention, a screw pump stator end face structure includes: A metal sleeve having a through hole along its axial direction; A rubber bushing is adhered to the through hole. The rubber bushing has an internal core. Both ends of the rubber bushing have snap-fit ​​portions extending out of the through hole, and the two snap-fit ​​portions respectively cover the two end faces of the metal sleeve. Both end faces of the rubber bushing have outer ring bosses. The rubber bushing has a concave surface in the inner ring area of ​​the outer ring bosses. The distance between the two outer ring bosses is greater than the distance between the two concave surfaces. The port of the internal core is located on the concave surface.

[0007] The screw pump stator end face structure according to embodiments of the present invention has at least the following beneficial effects: By providing outer ring bosses on both end faces of the rubber bushing and a concave surface in the inner ring region of the outer ring bosses, the stator stator end face structure of the present invention ensures that when the stator is assembled with the outer casing, the compressive force of the outer casing mainly acts on the outer ring bosses. Because a gradient structure is formed between the outer ring bosses and the concave surface, the deformation caused by the pressure on the outer ring bosses is difficult to be transmitted to the inner ring region where the concave surface is located. This effectively prevents the internal core from deforming due to compression, ensuring the fitting accuracy between the internal core and the rotor, and improving the conveying efficiency and operational stability of the screw pump. Simultaneously, the outer ring bosses allow the ports of the internal core to be separated from the outer casing, preventing damage to the internal core ports due to friction with the outer casing and effectively extending the service life of the rubber bushing.

[0008] According to some embodiments of the present invention, the end face of the outer ring boss away from the metal sleeve is used as the contact surface of the outer ring boss, and the contact surface is perpendicular to the central axis of the metal sleeve.

[0009] According to some embodiments of the present invention, the concave surface has a planar structure and is parallel to the contact surface.

[0010] According to some embodiments of the present invention, the concave surface has a flared structure, and the inner diameter of the concave surface increases in the direction close to the contact surface.

[0011] According to some embodiments of the present invention, the height of the outer ring boss is 0.5 mm to 1.5 mm.

[0012] According to some embodiments of the present invention, the rubber bushing and the metal sleeve are adhered and fixed by a vulcanization process.

[0013] According to a second aspect embodiment of the present invention, a stator forming die is used to process the above-described screw pump stator end face structure, comprising: The upper mold base is provided with an upper mounting hole; The lower mold base has a lower mounting hole, and the metal sleeve is snapped between the upper mold base and the lower mold base. The upper mold base and the lower mold base are detachably connected by a connecting rod. A stator core has its two ends inserted into the upper mounting hole and the lower mounting hole, respectively. The stator core passes through the through hole of the metal sleeve. The metal sleeve and the stator core together form a cavity. The upper mold base has a feed hole communicating with the cavity, and the lower mold base has a vent hole communicating with the cavity. Both the upper mold base and the lower mold base have grooves communicating with the cavity. The inner diameter of the groove is larger than the inner diameter of the metal sleeve. The area between the groove and the end face of the metal sleeve forms an end cavity for forming the snap-fit ​​part. An inner ring boss is provided in the middle of the groove. The upper mounting hole and the lower mounting hole are respectively located at the center of the two inner ring bosses. The inner ring boss has a forming circular surface parallel to the bottom of the groove.

[0014] According to a third aspect embodiment of the present invention, a stator forming die is used to process the above-described screw pump stator end face structure, comprising: The upper mold base is provided with an upper mounting hole; The lower mold base has a lower mounting hole, and the metal sleeve is snapped between the upper mold base and the lower mold base. The upper mold base and the lower mold base are detachably connected by a connecting rod. A stator mold core has its two ends inserted into the upper mounting hole and the lower mounting hole, respectively. The stator mold core passes through the through hole of the metal sleeve. The metal sleeve and the stator mold core together form a cavity. The upper mold base has a feed hole communicating with the cavity, and the lower mold base has a vent hole communicating with the cavity. Both the upper mold base and the lower mold base have grooves communicating with the cavity. The inner diameter of the groove is larger than the inner diameter of the metal sleeve. The area between the groove and the end face of the metal sleeve forms an end cavity for forming the snap-fit ​​part. An inner ring boss is provided in the middle of the groove. The upper mounting hole and the lower mounting hole are respectively located at the center of the two inner ring bosses. The connection between the stator mold core and the inner ring boss is provided with an inclined surface for forming a flared mouth.

[0015] According to some embodiments of the present invention, one of the inner ring bosses is provided with an inclined surface for forming a flared mouth, and the inclined surface is provided with a positioning irregular surface parallel to the bottom of the groove, and one side of the rotor mold core is provided with an irregular plane for aligning with the positioning irregular surface; the other inner ring boss is provided with an abutting circular surface parallel to the bottom of the groove, and the other side of the rotor mold core is provided with a forming part abutting against the abutting circular surface, and the forming part is provided with an inclined surface for forming a flared mouth.

[0016] According to some embodiments of the present invention, both inner ring bosses are provided with inclined surfaces for forming flared mouths, and the inclined surfaces are provided with positioning irregular surfaces parallel to the bottom of the groove. Both sides of the rotor mold core are provided with irregular planes for aligning with the positioning irregular surfaces.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of a screw pump stator provided in an embodiment of the present invention; Figure 2 yes Figure 1 An exploded three-dimensional view of the screw pump stator is shown. Figure 3 yes Figure 1 The diagram shows a cross-sectional view of the screw pump stator. Figure 4 This is a three-dimensional structural schematic diagram of another screw pump stator provided in an embodiment of the present invention; Figure 5 yes Figure 4 The diagram shows a cross-sectional view of the screw pump stator. Figure 6 This is a cross-sectional view of a stator forming mold provided in an embodiment of the present invention; Figure 7 This is an exploded perspective view of a stator forming mold provided in an embodiment of the present invention, with the metal sleeve concealed. Figure 8 This is a cross-sectional view of another stator forming mold provided in an embodiment of the present invention; Figure 9 This is an exploded perspective view of another stator forming mold provided in an embodiment of the present invention after the metal sleeve is hidden.

[0019] In the attached diagram: 100-metal sleeve, 200-rubber bushing, 110-through hole, 210-internal core, 220-clamping part, 300-outer ring boss, 310-contact surface, 400-concave surface, 221-port, 410-planar structure, 420-flare structure, 500-upper mold base, 600-lower mold base, 700-rotor mold core, 510-upper mounting hole, 610-lower mounting hole, 5 20- Bolt hole, 120- Clip connector, 530- Groove, 540- End cavity, 130- Cavity, 550- Feed hole, 650- Vent hole, 560- Inner ring boss, 561- Forming round surface, 710- Irregular plane, 720- Upper central shaft, 730- Lower central shaft, 562- Inclined surface, 563- Positioning irregular surface, 564- Abutting round surface, 740- Forming part, 741- Circular surface. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0022] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0024] like Figures 1 to 3 As shown, this embodiment of the invention provides a stator end face structure for a screw pump, comprising a metal sleeve 100 and a rubber bushing 200. The metal sleeve 100 serves as the supporting foundation for the entire stator end face structure, providing an installation carrier for the rubber bushing 200, ensuring the structural strength and stability of the entire stator, and preventing deformation or damage to the stator under long-term high-pressure, high-frequency vibration operating conditions. The metal sleeve 100 is made of high-strength steel, specifically 45# steel. 45# steel has good mechanical strength, wear resistance, and toughness, meeting the stress requirements of the screw pump during operation. Simultaneously, the steel has excellent machinability, facilitating drilling, grinding, and other machining processes for the through hole 110. The metal sleeve 100 has an overall cylindrical structure, with a through hole 110 extending along its central axis. The through hole 110 is used to assemble the rubber bushing 200. The rubber bushing 200 is tightly adhered to the inside of the through hole 110, preventing gaps between them and preventing fluid from seeping into the gaps during operation, which could cause the rubber bushing 200 to separate from the metal sleeve 100 and affect the connection stability.

[0025] On the other side, the rubber bushing 200 is a key component that cooperates with the rotor to form a sealed chamber. It is made of oil-resistant, wear-resistant, and aging-resistant nitrile rubber. This material has good elasticity, sealing properties, and media resistance, which can meet the working requirements of screw pumps for conveying various fluids. At the same time, nitrile rubber has excellent compressive strength, and can produce a certain amount of elastic deformation when squeezed by the outer shell, and can quickly return to its original shape after deformation. The inner wall of the rubber bushing 200 is provided with an internal core 210. The structure of the internal core 210 is adapted to the shape of the rotor and has a spiral structure. Its spiral parameters are perfectly matched with the rotor, ensuring that the rotor can rotate smoothly in the internal core 210. At the same time, a tight sealed chamber is formed between the two. When the rotor rotates, the sealed chamber moves along the axial direction to realize the intake and discharge of fluid.

[0026] In addition, the rubber bushing 200 has locking portions 220 extending from the through holes 110 of the metal sleeve 100 at both ends. The two locking portions 220 cover the two end faces of the metal sleeve 100, and their main function is to lock the relative position of the rubber bushing 200 and the metal sleeve 100, preventing the rubber bushing 200 from dislodging from the through holes 110 along the central axis of the metal sleeve 100, thus ensuring the stability of the connection. The locking portions 220 and the rubber bushing 200 are integrally formed, improving the integrity and robustness of the overall structure while reducing processing steps and lowering processing costs. The overall shape of the locking portions 220 is adapted to the end face of the metal sleeve 100, forming a ring structure, and its outer diameter is approximately the same as the outer diameter of the metal sleeve 100, ensuring a smooth appearance on the outer circumference of the stator. Since the rubber bushing 200 is snapped onto both ends of the metal sleeve 100 by two snap-fit ​​parts 220, when the rubber bushing 200 is subjected to axial tensile force from either side, the rubber bushing 200 can still firmly cover the two end faces of the metal sleeve 100, preventing the rubber bushing 200 from coming off and ensuring the reliability of the connection.

[0027] Meanwhile, both end faces of the rubber bushing 200 are provided with outer ring bosses 300. The outer ring bosses 300 are key structures for achieving a sealed connection between the stator and the housing and preventing deformation of the internal core 210. They are part of the snap-fit ​​portion 220 of the rubber bushing 200. The outer ring bosses 300 have a ring structure and surround the outer ring position of the end face of the rubber bushing 200. Their outer diameter is similar to the outer diameter of the snap-fit ​​portion 220. The inner diameter of the outer ring bosses 300 needs to be set according to the size of the port 221 of the internal core 210 to ensure that the outer ring bosses 300 are located around the port 221 of the internal core 210 and form a height difference with the port 221 of the internal core 210. The height of the outer ring boss 300 is controlled between 0.5mm and 1.5mm. This height range has been verified by multiple tests to ensure that the outer ring boss 300 has sufficient compressive strength and can produce appropriate elastic deformation when squeezed by the outer shell to achieve a sealed connection. However, an excessively set height will increase the elastic deformation of the outer ring boss 300, making it prone to permanent deformation and affecting the sealing performance and service life.

[0028] The surface of the outer ring boss 300, i.e., the end face furthest from the metal sleeve 100, serves as the contact surface 310 that contacts the outer casing. This contact surface 310 is perpendicular to the central axis of the metal sleeve 100. This arrangement ensures the flatness of the outer ring boss 300 when connected to the outer casing, allowing the extrusion pressure from the outer casing to be evenly distributed on the contact surface 310 of the outer ring boss 300. This prevents uneven pressure distribution from causing excessive local deformation of the outer ring boss 300, which could affect the sealing effect and prevent leakage. The perpendicularity of the contact surface 310 to the central axis of the metal sleeve 100 ensures the coaxiality of the stator and outer casing during assembly, preventing eccentric installation of the stator, preventing uneven wear between the rotor and the internal core 210, and extending the service life of the rotor and the rubber bushing 200.

[0029] Next, the rubber bushing 200 has a concave surface 400 in the inner ring region of the outer ring boss 300. The concave surface 400 and the outer ring boss 300 form a stepped structure, the main function of which is to isolate the deformation of the outer ring boss 300 and prevent the deformation of the outer ring boss 300 from being transmitted to the inner core 210. The port 221 of the inner core 210 is located on the concave surface 400, that is, the two end openings of the inner core 210 are respectively located on the concave surface 400 on both end faces of the rubber bushing 200. In this embodiment, the concave surface 400 is specifically a planar structure 410, in which case the concave surface 400 is parallel to the contact surface 310 of the outer ring boss 300. The concave surface 400 of the planar structure 410 is easy to process, facilitates mass production, and can effectively reduce processing costs. At the same time, the concave surface 400 of the planar structure 410 and the port 221 of the inner core 210 are smoothly connected and will not obstruct the flow of fluid, making it suitable for scenarios where the requirements for fluid flow resistance are not high.

[0030] To accommodate the concave surface 400, the distance between the two outer ring bosses 300 is greater than the distance between the two concave surfaces 400. This dimensional relationship creates a gradient difference between the outer ring bosses 300 and the concave surfaces 400. When the outer ring bosses 300 are subjected to elastic deformation by the outer shell, the deformation transmission path is blocked by the stepped structure, preventing it from reaching the inner ring area where the concave surfaces 400 are located. This effectively protects the internal core 210 and prevents it from deforming. Furthermore, this arrangement separates the ports 221 of the outer shell and the internal core 210, preventing direct contact and friction between the ports 221 of the internal core 210 and the outer shell during stator and outer shell assembly. This reduces the risk of damage to the ports 221 of the internal core 210 due to friction and further extends the service life of the rubber bushing 200.

[0031] In some embodiments of the present invention, the rubber bushing 200 and the metal sleeve 100 are bonded and fixed by a vulcanization process. Vulcanization is a common process for joining rubber and metal, which enables the rubber bushing 200 and the metal sleeve 100 to form a strong bond with high strength, capable of withstanding large axial tensile forces and radial pressures, thus preventing separation between them. Specific vulcanization process parameters are as follows: vulcanization temperature controlled between 150°C and 180°C, vulcanization time controlled between 30 min and 60 min, and vulcanization pressure controlled between 10 MPa and 15 MPa. This parameter range ensures the adhesion strength between the rubber bushing 200 and the metal sleeve 100.

[0032] like Figure 4 and Figure 5 As shown, in this embodiment, the concave surface 400 is specifically a flared structure 420, with its cone angle controlled between 10° and 15°. The inner diameter of the concave surface 400 increases along the direction close to the contact surface 310 of the outer ring boss 300, that is, the larger opening of the flared mouth faces the contact surface 310, and the smaller opening faces the through hole 110 of the metal sleeve 100. The flared structure 420 can reduce the resistance of the fluid during the flow process, making the stator discharge smoother and improving the conveying efficiency of the screw pump. It is suitable for scenarios with high requirements for fluid conveying efficiency.

[0033] like Figure 6 and Figure 7 As shown, this embodiment of the invention also provides a stator forming mold for processing screw pump stators with a concave surface 400 and a planar structure 410. Specifically, it includes an upper mold base 500, a lower mold base 600, a metal sleeve 100, and a rotor mold core 700. The upper mold base 500 serves as the upper support component of the mold, used to mount the upper end of the stator mold core and also provides a feeding channel. An upper mounting hole 510 is provided at the center of the upper mold base 500, the inner diameter of which matches the outer diameter of the upper central shaft 720 of the stator mold core, ensuring that the upper central shaft 720 of the stator mold core can be smoothly inserted into the upper mounting hole 510.

[0034] The lower mold base 600 is positioned opposite the upper mold base 500, serving as the lower support component of the mold. It is used to mount the lower end of the stator mold core and also provides an venting channel. The lower mold base 600 has a lower mounting hole 610 at its center, the inner diameter of which matches the outer diameter of the lower central shaft 730 of the stator mold core, ensuring that the lower central shaft 730 of the stator mold core can be smoothly inserted into the lower mounting hole 610.

[0035] The metal sleeve 100 is snapped between the upper mold base 500 and the lower mold base 600, serving as the mounting carrier for the rubber bushing 200. Since the rubber needs to be adhered to the through hole 110 of the metal sleeve 100 through a vulcanization process, and the molding of the internal core 210 relies on the rotor mold core 700, the metal sleeve 100 differs from the upper mold base 500, lower mold base 600, or rotor mold core 700; it is not a component of the mold but rather a component of the product. That is, one metal sleeve 100 is consumed for each screw pump stator produced, and the metal sleeve 100 cannot be repeatedly ejected from the mold. During processing, the metal sleeve 100 needs to be snapped between the upper mold base 500 and the lower mold base 600. The upper mold base 500 and the lower mold base 600 are detachably connected by a connecting rod (not shown in the attached diagram). The connecting rod is used to lock and fix the upper and lower molds, ensuring that there are no gaps between the upper and lower molds during molding, preventing rubber material leakage, and ensuring the overall stability of the mold. The connecting rod uses high-strength bolts, usually two or four in number. Correspondingly, the upper mold base 500 and the lower mold base 600 are provided with bolt holes 520 that are compatible with the connecting rod. The two ends of the connecting rod pass through the bolt holes 520 of the upper mold base 500 and the lower mold base 600 respectively, and are locked and fixed by nuts.

[0036] To machine the snap-fit ​​portion 220 of the rubber bushing 200, snap-fit ​​connectors 120 are provided at both ends of the metal sleeve 100. The snap-fit ​​connectors 120 are formed by cutting the outer peripheral surface of the metal sleeve 100, so the outer diameter of the snap-fit ​​connectors 120 is smaller than the outer diameter of the metal sleeve 100. Both the upper mold base 500 and the lower mold base 600 are provided with grooves 530 for inserting the snap-fit ​​connectors 120. The grooves 530 have an annular structure, and their inner diameter is consistent with the outer diameter of the snap-fit ​​connectors 120. The inner diameter of the snap-fit ​​connectors 120 is larger than the inner diameter of the metal sleeve 100 but smaller than the outer diameter of the metal sleeve 100, and the height of the snap-fit ​​connectors 120 is smaller than the depth of the grooves 530. This ensures that when the metal sleeve 100 is engaged with the groove 530 via the snap-fit ​​connector 120, a gap exists between the end face of the metal sleeve 100 and the bottom of the groove 530. This gap serves as the end cavity 540 for forming the snap-fit ​​part 220, ensuring that the formed snap-fit ​​part 220 can tightly cover the end face of the metal sleeve 100. The metal sleeve 100 is engaged with the grooves 530 of the upper mold base 500 and the lower mold base 600 via the snap-fit ​​connectors 120 at both ends, thus achieving the positioning and fixation of the metal sleeve 100 in the mold.

[0037] During stator forming mold assembly, firstly, the lower central shaft 730 of the rotor mold core 700 is placed into the lower mounting hole 610 of the lower mold base 600. Then, the metal sleeve 100 is fitted onto the outer circumference of the rotor mold core 700 from top to bottom. At this time, the metal sleeve 100 is engaged with the groove 530 of the lower mold base 600 through the snap-fit ​​connector 120 located at the lower end. Finally, the upper mounting hole 510 of the upper mold base 500 is fitted into the upper central shaft 720 of the rotor mold core 700. During this process, the metal sleeve 100 is engaged with the groove 530 of the upper mold base 500 through the snap-fit ​​connector 120 located at the upper end. Inside the mold, the metal sleeve 100 and the stator mold core together form a cavity 130, and the grooves 530 of both the upper mold base 500 and the lower mold base 600 are connected to the cavity 130. The upper mold base 500 is provided with a feed hole 550 communicating with the cavity 130. Its inner diameter is controlled at about 6mm. One end of the feed hole 550 is connected to an external injection equipment, and the other end passes through the inner wall of the upper mold base 500 and communicates with the cavity 130. It is used to inject molten rubber material into the cavity 130 to form the rubber bushing 200. The lower mold base 600 is provided with a vent hole 650 communicating with the cavity 130 on one side. Its inner diameter is controlled at about 3mm. One end of the vent hole 650 passes through the outer wall of the lower mold base 600 and communicates with the atmosphere. The other end passes through the inner wall of the lower mold base 600 and communicates with the cavity 130. It is used to expel the air inside the cavity 130 to avoid defects such as air bubbles and pores inside the molded rubber bushing 200, which would affect the performance and quality of the rubber bushing 200.

[0038] To machine the concave surface 400 of the rubber bushing 200, an inner ring boss 560 is provided in the middle of the groove 530 of both the upper mold base 500 and the lower mold base 600. The inner ring boss 560 has a cylindrical structure, and its outer diameter is the inner diameter of the concave surface 400. In this embodiment, since the width of the outer ring boss 300 is greater than the thickness of the metal sleeve 100, the outer diameter of the inner ring boss 560 is smaller than the inner diameter of the metal sleeve 100. Furthermore, the upper mounting hole 510 and the lower mounting hole 610 are respectively located at the center of the two inner ring bosses 560, ensuring that the stator mold core can be accurately installed at the center of the mold. Since the concave surface 400 of the rubber bushing 200 is a planar structure 410, the inner ring boss 560 is provided with a forming circular surface 561 parallel to the bottom of the groove 530. The forming circular surface 561 is used to form the planar structure 410 of the rubber bushing 200, while the bottom of the groove 530 is used to form the contact surface 310 of the rubber bushing 200.

[0039] The rotor mold core 700 is a standardized rotor made of high-strength alloy steel, specifically Cr12MoV. During the molding process, the rotor mold core 700 serves as the internal core 210 of the rubber bushing 200. In the subsequent demolding process, the rotor mold core 700 needs to be removed from the internal core 210 of the stator. Therefore, the rotor mold core 700 can be reused as a mold. Since the internal core 210 of the rubber bushing 200 is a double-headed spiral with a cross-sectional profile of “∞”, the rotor mold core 700 also has a cross-sectional profile of “∞”. The rotor mold core 700 has irregular planes 710 on both sides, and the irregular planes 710 are in the shape of “∞”. The upper central shaft 720 and the lower central shaft 730 of the rotor mold core 700 are respectively located on the two irregular planes 710. The rotor mold core 700 abuts against the forming circular surface 561 of the upper mold base 500 and the forming circular surface 561 of the lower mold base 600 through the two irregular planes 710.

[0040] like Figure 8 and Figure 9 As shown, this embodiment of the invention also provides a stator forming mold, which is used to process a screw pump stator with a concave surface 400 having a flared mouth structure 420. The structure and dimensional parameters of most of its components are the same as those of the stator forming mold in the previous embodiment. The parts that are repeated will not be described again. Only the components that are different from those in the previous embodiment will be described in detail. The following focuses on the structural differences of the stator mold core and the inner ring boss 560, as well as the specific structure of different flared mouth forming embodiments.

[0041] Unlike the embodiments described above, the stator forming mold of this embodiment has a bevel 562 at the connection between the stator core and the inner ring boss 560 for forming a flared opening. The structure of the bevel 562 is adapted to the flared opening structure 420 of the rubber bushing 200, and is used to form the flared opening structure 420 during the forming of the rubber bushing 200. The inner ring boss 560 has two different embodiments, which will be described in detail below.

[0042] Example a: One inner ring boss 560 is provided with a bevel 562 for forming a flared mouth. The bevel 562 is provided with a positioning irregular surface 563 parallel to the bottom of the groove 530. One side of the stator mold core is provided with an irregular plane 710 for facing the positioning irregular surface 563. The other inner ring boss 560 is provided with an abutting circular surface 564 parallel to the bottom of the groove 530. The other side of the stator mold core is provided with a forming part 740 abutting against the abutting circular surface 564. The forming part 740 is provided with a bevel 562 for forming a flared mouth. Specifically, an inclined surface 562 is provided on the inner ring boss 560 of the lower mold base 600. The cone angle of the inclined surface 562 is 10° to 15°. The positioning irregular surface 563 on the inclined surface 562 is in the shape of "∞". The positioning irregular surface 563 is parallel to the bottom of the groove 530. Its function is to accurately align with one side of the irregular plane 710 of the stator mold core, so as to avoid deviation of the flared structure 420 during molding. The inner ring boss 560 of the upper mold base 500 is provided with an abutment circular surface 564. The abutment circular surface 564 is parallel to the bottom of the groove 530 and is used to abut with the molding part 740 on the other side of the stator mold core to realize the positioning and installation of the stator mold core. The stator mold core forming part 740 has a circular surface 741 that abuts against the abutting circular surface 564. Starting from the circular surface 741, the forming part 740 has a downward inclined surface 562 facing the lower mold base 600. The cone angle of the inclined surface 562 is the same as the cone angle of the inclined surface 562 of the inner ring boss 560 of the lower mold base 600. The upper and lower inclined surfaces 562 are used to form the flared structure 420 of the rubber bushing 200. At this time, the upper central shaft 720 of the rotor mold core 700 is located on the circular surface 741, and the lower central shaft 730 of the rotor mold core 700 is located on the irregular plane 710.

[0043] The advantage of embodiment a is that there is only one set of positioning irregular surfaces 563 and irregular planes 710 that need to be aligned with each other, and the contact of the abutting circular surface 564 and the circular surface 741 does not need to distinguish the directionality. Therefore, the positioning difficulty of embodiment a is low, and even if there is a slight dimensional error in the stator mold core, it can meet the requirements of normal production.

[0044] Example b: Both inner ring bosses 560 are provided with inclined surfaces 562 for forming the flared opening. The inclined surfaces 562 have positioning irregular surfaces 563 parallel to the bottom of the grooves 530. The rotor mold core 700 has irregular planes 710 on both sides. Specifically, the cone angle of the inclined surfaces 562 on the inner ring bosses 560 is 10° to 15°. The positioning irregular surfaces 563 on the inclined surfaces 562 are in the shape of an infinity symbol ("∞"). The positioning irregular surfaces 563 are parallel to the bottom of the grooves 530, and their function is to precisely align with the irregular planes 710 of the stator mold core, preventing deviations in the flared opening structure 420 during forming. At this time, the upper central shaft 720 and the lower central shaft 730 of the rotor mold core 700 are respectively located on the two irregular planes 710.

[0045] Compared to embodiment a, the disadvantage of embodiment b is that there are two sets of positioning irregular surfaces 563 and irregular planes 710 that need to be aligned with each other. If the two positioning irregular surfaces 563 cannot be completely aligned with the two irregular planes 710 of the stator mold core, the flared structure 420 after molding will be deviated, resulting in the production of defective products. Therefore, if there is a dimensional error in the stator mold core, embodiment b cannot be used for production.

[0046] Comparing Embodiment a and Embodiment b, Embodiment a is preferred because it has low positioning difficulty and low requirements for the machining accuracy of the stator mold core, which can effectively reduce the defect rate and meet the machining needs of most scenarios, balancing machining accuracy and production cost.

[0047] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. The stator end face structure of a screw pump, characterized in that, include: A metal sleeve (100) has a through hole (110) along the axial direction. A rubber bushing (200) is adhered to the through hole (110). The rubber bushing (200) has an internal core (210). Both ends of the rubber bushing (200) have snap-fit ​​portions (220) extending out of the through hole (110). The two snap-fit ​​portions (220) cover the two end faces of the metal sleeve (100). Both end faces of the rubber bushing (200) have outer ring bosses (300). The rubber bushing (200) has a concave surface (400) in the inner ring area of ​​the outer ring bosses (300). The distance between the two outer ring bosses (300) is greater than the distance between the two concave surfaces (400). The port (221) of the internal core (210) is located on the concave surface (400).

2. The screw pump stator end face structure according to claim 1, characterized in that: The end face of the outer ring boss (300) away from the metal sleeve (100) is used as the contact surface (310) of the outer ring boss (300), and the contact surface (310) is perpendicular to the central axis of the metal sleeve (100).

3. The screw pump stator end face structure according to claim 2, characterized in that: The concave surface (400) is a planar structure (410), and the concave surface (400) is parallel to the contact surface (310).

4. The screw pump stator end face structure according to claim 2, characterized in that: The concave surface (400) has a flared structure (420), and the inner diameter of the concave surface (400) increases in the direction close to the contact surface (310).

5. The screw pump stator end face structure according to claim 1, characterized in that: The height of the outer ring boss (300) is 0.5mm to 1.5mm.

6. The screw pump stator end face structure according to claim 1, characterized in that: The rubber bushing (200) and the metal sleeve (100) are bonded and fixed together by a vulcanization process.

7. A stator forming mold, used for processing the stator end face structure of the screw pump as described in claim 3, characterized in that, include: Upper mold base (500) is provided with upper mounting hole (510); The lower mold base (600) has a lower mounting hole (610), and the metal sleeve (100) is snapped between the upper mold base (500) and the lower mold base (600). The upper mold base (500) and the lower mold base (600) are detachably connected by a connecting rod. A stator mold core has its two ends inserted into the upper mounting hole (510) and the lower mounting hole (610) respectively. The stator mold core passes through the through hole (110) of the metal sleeve (100). The metal sleeve (100) and the stator mold core together form a cavity (130). The upper mold base (500) is provided with a feed hole (550) communicating with the cavity (130), and the lower mold base (600) is provided with a vent hole (650) communicating with the cavity (130). Both the upper mold base (500) and the lower mold base (600) are provided with a vent hole (650) communicating with the cavity (130). The groove (530) has an inner diameter larger than the inner diameter of the metal sleeve (100). The area between the groove (530) and the end face of the metal sleeve (100) forms an end cavity (540) for forming the snap-fit ​​part (220). The groove (530) has an inner ring boss (560) in the middle. The upper mounting hole (510) and the lower mounting hole (610) are respectively located at the center of the two inner ring bosses (560). The inner ring boss (560) has a forming circular surface (561) parallel to the bottom of the groove (530).

8. A stator forming mold, used for processing the stator end face structure of the screw pump as described in claim 4, characterized in that, include: Upper mold base (500) is provided with upper mounting hole (510); The lower mold base (600) has a lower mounting hole (610), and the metal sleeve (100) is snapped between the upper mold base (500) and the lower mold base (600). The upper mold base (500) and the lower mold base (600) are detachably connected by a connecting rod. The stator mold core has its two ends inserted into the upper mounting hole (510) and the lower mounting hole (610) respectively. The stator mold core passes through the through hole (110) of the metal sleeve (100). The metal sleeve (100) and the stator mold core together form a cavity (130). The upper mold base (500) is provided with a feed hole (550) communicating with the cavity (130), and the lower mold base (600) is provided with a vent hole (650) communicating with the cavity (130). Both the upper mold base (500) and the lower mold base (600) are provided with recesses communicating with the cavity (130). The groove (530) has an inner diameter larger than the inner diameter of the metal sleeve (100). The area between the groove (530) and the end face of the metal sleeve (100) forms an end cavity (540) for forming the snap-fit ​​part (220). The groove (530) has an inner ring boss (560) in the middle. The upper mounting hole (510) and the lower mounting hole (610) are respectively located at the center of the two inner ring bosses (560). The connection between the stator mold core and the inner ring boss (560) has a bevel (562) for forming a flared mouth.

9. The stator forming mold according to claim 8, characterized in that: One of the inner ring bosses (560) is provided with a bevel (562) for forming a flared mouth. The bevel (562) is provided with a positioning irregular surface (563) parallel to the bottom of the groove (530). One side of the rotor mold core (700) is provided with an irregular plane (710) for aligning with the positioning irregular surface (563). The other inner ring boss (560) is provided with an abutting circular surface (564) parallel to the bottom of the groove (530). The other side of the rotor mold core (700) is provided with a forming part (740) abutting against the abutting circular surface (564). The forming part (740) is provided with a bevel (562) for forming a flared mouth.

10. The stator forming mold according to claim 8, characterized in that: Both inner ring bosses (560) are provided with inclined surfaces (562) for forming flared mouths. The inclined surfaces (562) are provided with positioning irregular surfaces (563) parallel to the bottom of the groove (530). Both sides of the rotor mold core (700) are provided with irregular planes (710) for aligning with the positioning irregular surfaces (563).

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