Pipeline connecting piece mold, pipeline unit, pipeline connecting piece and injection molding method

Abstract

The embodiment of the invention provides a pipeline connecting piece mold, a pipeline unit, a pipeline connecting piece and an injection molding method. The injection molding mold core is arranged in the injection molding mold cavity, a first injection molding space allowing a first plastic material to be injected and molded into the first part is determined in the injection molding mold cavity, and the injection molding mold core is provided with a contact increasing molding structure for molding a first contact increasing part on the first part; the injection mold core is used for being removed out of the injection mold cavity after the first part is formed, so that a second plastic material is allowed to be injected into the injection mold cavity to form a second part, the second part and the first part are integrally formed, and a second contact increasing part in concave-convex fit with the first contact increasing part is naturally formed; the first part and the second part are integrally formed into the pipeline connecting piece. The first contact increasing part is formed through the injection mold core, and the second contact increasing part in concave-convex fit is naturally formed after the mold core is removed, so that the two parts are combined into'mechanical engagement and material fusion ', the connection strength and the sealing performance are improved, and separation and leakage are avoided.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of pipe connection, and particularly relates to a pipe connection mold, a pipe unit, a pipe connection and an injection molding method. BACKGROUND

[0002] In automobiles, household appliances, water heating systems and industrial fluid transmission equipment, pipe connections are the core components for realizing the butt joint of different pipes and ensuring the stable transmission of fluids (liquids or gases), and the connection sealing and structural strength directly determine the operation reliability and service life of the entire transmission system. With the improvement of the performance requirements of equipment on pipe connections, a single material has been difficult to meet the needs of complex working conditions, for example, some areas need to have high pressure resistance and temperature resistance, and another part needs to have flexibility to adapt to assembly deviation or vibration environment. SUMMARY

[0003] In view of the above-mentioned shortcomings of the prior art, the purpose of the present disclosure is to provide a pipe connection mold, a pipe unit, a pipe connection and an injection molding method to solve the problems in the related art.

[0004] The first aspect of the present disclosure provides a pipe connection mold, wherein the pipe connection mold is used for forming a pipe connection, and comprises:

[0005] an injection molding cavity;

[0006] an injection molding core arranged in the injection molding cavity, wherein the injection molding cavity defines a first injection molding space allowing a first plastic material to be injected and molded into a first part, the injection molding core is provided with a touch-up molding structure for molding a first touch-up portion on the first part; and the injection molding core is removed from the injection molding cavity after the first part is molded, so that the injection molding cavity allows a second plastic material to be injected and molded into a second part, the second part is integrally molded with the first part and naturally forms a second touch-up portion in concave-convex cooperation with the first touch-up portion; and the first part and the second part are integrally molded into the pipe connection.

[0007] In an embodiment of the first aspect, the touch-up molding structure comprises a concave-convex structure arranged in a circumferential direction at intervals along the outer side surface of the injection molding core, or a thread structure extending in a circumferential direction along the outer side surface of the injection molding core.

[0008] In an embodiment of the first aspect, the injection molding model is further provided with a clamping molding structure for molding a clamping portion on the first part; the clamping portion is molded at an opening of the first part towards the second part; and the clamping portion extends to the injection molding cavity of the second part, so that the second plastic material can flow into the gap between the clamping portions, for clamping connection of the molded first part and second part.

[0009] The second aspect of the present disclosure provides a method for injection molding a pipe connector, wherein the pipe connector mold of any one of the first aspect is used; the method comprises:

[0010] The injection mold core is arranged in the injection mold cavity, so that the first injection space is formed between the injection mold core and the injection mold cavity, and the touch-up forming structure of the injection mold core is located in the first injection space;

[0011] The first plastic material is injected into the first injection space, and the first part is formed after the first plastic material is solidified, and the first touch-up part is formed on the first part through the touch-up forming structure;

[0012] After the first part is solidified, the injection mold core is removed from the injection mold cavity, so that a space allowing the injection of the second plastic material is formed in the injection mold cavity;

[0013] The second plastic material is injected into the injection mold cavity, the second plastic material is fused with the first part, and the second part is formed after solidification, the second part is integrally formed with the first part; and the second touch-up part matched with the first touch-up part is naturally formed on the second part, and the first part and the second part jointly form the pipe connector.

[0014] The third aspect of the present disclosure provides a pipe connector, which is injection molded by the pipe connector mold of any one of the first aspect, and comprises a first connector made of a first plastic material and a second connector made of a second plastic material.

[0015] In the embodiment of the third aspect, the first plastic material at least includes one of the following: nylon material, polyphenyl ether material;

[0016] The second plastic material at least includes one of the following: olefin material, fluoroplastic material.

[0017] In the embodiment of the third aspect, the first connector corresponds to a connecting pipe, and the hardness of the first plastic material is lower than that of the second plastic material.

[0018] The fourth aspect of the present disclosure provides a pipe unit, which comprises:

[0019] At least one pipe connector of any one of the third aspect;

[0020] The pipe connected with the pipe connector.

[0021] In the embodiment of the fourth aspect, the pipe connector is connected with the connecting port of the pipe by socket welding and / or camber welding.

[0022] In an embodiment of the fourth aspect, the material hardness of one end of the pipe connector connected with the pipe is lower than the other end of the pipe connector.

[0023] The beneficial effects of the present disclosure: by injection molding core forming the first contact part, the second contact part is naturally formed after the core is removed, which makes the two parts combined as "mechanical occlusion + same type material fusion", improves the connection strength and sealing, and avoids separation and leakage. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The cross-sectional view of the pipe connector in an embodiment of the present disclosure is shown.

[0025] Figure 2 The exploded schematic view of the pipe connector in an embodiment of the present disclosure is shown.

[0026] Figure 3 The flowchart of the injection molding method of the pipe connector in another embodiment of the present disclosure is shown.

[0027] Figure 4 The overall structure schematic view of the pipe connector installed on the pipe in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0028] The embodiments of the present disclosure are described below through specific and concrete examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the disclosed information. The present disclosure can also be implemented or applied in different specific embodiments or modules, and the details in the present disclosure can be modified or changed according to different views and application modules without departing from the spirit of the present disclosure. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0029] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the present disclosure. The present disclosure can be embodied in various different forms, and is not limited to the embodiments described here.

[0030] In the present disclosure, the expressions of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics expressed in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. Moreover, the specific features, structures, materials or characteristics expressed can be combined in any one or group of embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or features of different embodiments or examples expressed in the present disclosure without contradiction.

[0031] Furthermore, the terms "first", "second", etc. are used herein only to distinguish one element from another and do not imply a relative importance or a specific order. Thus, a feature specified as "first" or "second" can include at least one of the features explicitly mentioned.

[0032] For the sake of clearness of the present disclosure, the devices irrelevant to the description are omitted and the same reference numerals are used to designate the same elements throughout the specification.

[0033] Throughout the specification, when it is said that an element is "connected" to another element, this includes not only a case where they are "directly connected", but also a case where other elements are interposed therebetween and they are "indirectly connected". In addition, when it is said that an element "includes" a certain constituent element, unless specifically stated to the contrary, other constituent elements are not excluded, but it means that other constituent elements can be further included.

[0034] Although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first interface and a second interface, etc. are distinguished from each other. Also, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", when used herein, specify the presence of stated features, steps, operations, elements, modules, items, species, and / or groups but do not preclude the presence or addition of one or more other features, steps, operations, elements, modules, items, species, and / or groups thereof. As used herein, the terms "or" and "and / or" are to be interpreted as inclusive, i.e., as meaning one or any combination of items. Thus, "A, B or C" or "A, B and / or C" means any of the following: A; B; C; A and B; A and C; B and C; A, B and C. An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.

[0035] The professional terms used herein are used only to refer to specific embodiments and are not intended to limit the present disclosure. As used herein, the singular form is intended to include the plural form as well unless the context clearly indicates otherwise. The meaning of "include", as used in the specification, is to incorporate the specific feature, region, integer, step, operation, element, and / or component, but not to exclude the existence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0036] Although not defined differently, the technical terms and scientific terms used herein include the technical terms and scientific terms commonly used in the technical field to which the present disclosure belongs, and all the terms have the same meaning as generally understood by those skilled in the art to which the present disclosure belongs. The terms defined in the commonly used dictionary are additionally explained to have a meaning consistent with the relevant technical literature and the current prompt message, and are not over-interpreted as ideal or very formal meanings if not defined.

[0037] An embodiment of the present disclosure provides a pipe connector mold, wherein a pipe connector is formed.

[0038] In Figure 1 In the embodiment shown, the pipe connector mold is described based on the cross-sectional structure of the pipe connector. The pipe connector mold includes an injection mold cavity and an injection mold core arranged inside the injection mold cavity.

[0039] The injection mold core defines a first injection space in the injection mold cavity that allows the first part 100 to be injection molded by a first plastic material, and the injection mold core is provided with a touch-up molding structure for molding the first touch-up portion 110 on the first part 100. After the first part 100 is molded, the injection mold core is removed from the injection mold cavity, so that the injection mold cavity allows the second part 200 to be injection molded by a second plastic material. The second part 200 is integrally formed with the first part 100 and naturally forms a second touch-up portion 210 that is concave-convex matched with the first touch-up portion 110. The first part 100 and the second part 200 are integrally formed into the pipe connector.

[0040] Specifically, the injection mold cavity constitutes the outer mold structure of the mold, and the inner wall surface thereof is used to mold the outer surface profile of the pipe connector. The injection mold core is a structure for forming the first touch-up portion 110 on the first part 100. A protrusion or recess structure complementary to the shape of the first touch-up portion 110 is arranged at a specified region of the injection mold core, which serves as a touch-up molding structure. After the first plastic material (such as polyamide PA) is injected and cooled, the first touch-up portion 110, such as a ring-shaped ridge, a zigzag boss, a spiral rib, or a stepped groove, is directly formed at the end or connection area of the molded first part 100.

[0041] As shown in FIG. 1, the injection mold core can be arranged in the mold core in the second injection space only corresponding to the area enclosed by the block A, as long as it can form the first touch-up portion 110 on the first part 100 through its own structure, and play a role of sealing and limiting the molding boundary for the corresponding region of the first injection space, so as to meet the requirement of molding the first touch-up portion 110 on the first part 100. After the injection mold core is removed, the molding space for naturally forming the second touch-up portion 210 that is concave-convex matched with the first touch-up portion 110 on the second part 200 is reserved.

[0042] When the first part 100 is completed in the first injection space defined by the injection cavity and the injection core, the injection core can be extracted as a whole or transferred to the next station, so that the first part 100 with the first touch-up part 110 enters the subsequent molding process as an insert. Subsequently, in the second injection stage, the second plastic material (such as polyethylene PE) is injected and covers the end of the first part 100, especially flows around or fills the profile of the first touch-up part 110.

[0043] Since the first touch-up part 110 is a protruding or recessed structure directly molded by the injection core, after the second plastic material cools and solidifies, a second touch-up part 210 that matches the first touch-up part 110 in terms of concave and convex is naturally formed in the corresponding area. That is, when the first touch-up part 110 is a convex ridge, the second part 200 forms a matching groove around it; when the first touch-up part 110 is a groove, the second part 200 fills it to form a corresponding protrusion. The two are nested with each other to form a mechanical interlocking structure.

[0044] Optionally, please refer to Figure 1 and Figure 2 embodiments, the touch-up molding structure includes concave-convex structures arranged circumferentially along the outer side surface of the injection core, or thread structures extending circumferentially along the outer side surface of the injection core.

[0045] Specifically, the touch-up molding structure is directly arranged on the outer surface of the injection core, and is used to integrally form a corresponding first touch-up part 110 on the first part 100 of the pipe connector during the injection molding of the first plastic material (such as PA). Among them, the concave-convex structures arranged circumferentially along the outer side surface of the injection core refer to a plurality of annular protrusions and grooves or zigzag, undulating structures arranged alternately on the surface of the core, which are distributed in the connection interface region in the axial direction. After molding, the first part 100 forms annular convex ridges or grooves at the corresponding position, increasing the contact area with the subsequent second part 200 (such as PE material). In the second injection stage, the second plastic material flows into and covers these convex ridges or fills the grooves, and after cooling, a concave-convex matching interface that is nested with each other is formed, realizing mechanical interlocking and effectively improving the pull-out resistance, shear resistance and peel resistance.

[0046] Another optional form is a thread structure extending circumferentially along the outer side surface of the injection core, that is, a continuous spiral rib or spiral groove is arranged on the surface of the core, and the pitch and tooth shape can be designed according to the bonding strength requirement. Corresponding inner thread or outer thread features are formed on the first part 100 as the first touch-up part 110. When the second part 200 is injection molded, the melt flows along the thread groove and solidifies to form a reverse thread engagement structure, constituting a threaded connection. This spiral touch-up structure improves the bonding strength of the interface between the first part 100 and the second part 200.

[0047] Optionally, inFigure 2 In an embodiment, the injection molding model further comprises a clamping structure for forming the clamping portions 120 on the first part 100; the clamping portions 120 are formed at the opening of the first part 100 towards the second part 200; the clamping portions 120 extend into the injection molding cavity of the second part 200, so that the second plastic material can flow into the gap between the clamping portions 120, for the clamping connection of the first part 100 and the second part 200.

[0048] Specifically, the clamping portions 120 are flanges, clamping structures extending radially inward or outward from the end of the first part 100, which can be a plurality of circumferentially distributed cantilever lugs, or a continuous stepped flange. The clamping portions 120 are directly formed by the clamping structure in the mold, such as a groove on the mold core or a boss in the mold cavity, to ensure geometric accuracy and structural strength.

[0049] After the first part 100 is completed and demolded, the injection molding core is removed, and the first part 100 is transferred as an insert into the second injection molding process. At this time, the clamping portions 120 extend into the injection molding cavity of the second part 200, and when the second plastic material (such as polyethylene PE) is injected, the melt not only covers the outer periphery of the first part 100, but also flows into the gap between the clamping portions 120 or fills around the root, and fills the gap between the two clamping portions 120 after cooling.

[0050] Thus, the second part 200 forms a physical clamping with the clamping portions 120 after solidification - that is, the clamping portions 120 are "locked" by the material of the second part 200, forming a resistance to rotation or torsion. A mechanical interlocking effect similar to "riveting" or "reverse locking" is produced. It can effectively prevent axial separation or interface cracking between the first part 100 and the second part 200.

[0051] Another embodiment of the present disclosure provides an injection molding method of a pipeline connector, wherein the pipeline connector mold of any one of the above-mentioned first aspect is used; in Figure 3 In an embodiment, the injection molding method comprises:

[0052] S1: The injection molding core is arranged in the injection molding cavity, so that the first injection space is determined between the injection molding core and the injection molding cavity, and the increased touch forming structure of the injection molding core is located in the first injection space.

[0053] S2: The first plastic material is injected into the first injection space, and the first part 100 is formed after the first plastic material is solidified; the first increased touch portion 110 is formed on the first part 100 by the increased touch forming structure.

[0054] S3: After the first part 100 is solidified, the injection mold core is removed from the injection mold cavity, so that a space is formed in the injection mold cavity to allow the injection of a second plastic material.

[0055] S4: A second plastic material is injected into the injection mold cavity, which fuses with the first part 100 and forms a second part 200 after solidification, the second part 200 is integrally formed with the first part 100; and a second touch-up portion 210 is naturally formed on the second part 200, which is in concave-convex cooperation with the first touch-up portion 110, and the first part 100 and the second part 200 together form the pipeline connector.

[0056] Specifically, first, the injection mold core provided with the touch-up forming structure is installed in the injection mold cavity, so that a first injection space for forming the first part 100 is formed between the injection mold core and the injection mold cavity, and the touch-up forming structure (such as an annular ridge, a serrated structure, or a thread, etc.) on the injection mold core extends into the first injection space. Then, a first plastic material (such as polyamide PA) is injected into the first injection space, and after cooling and solidification, the first part 100 of the pipeline connector is formed. In this process, the touch-up forming structure on the injection mold core is integrally formed into the first touch-up portion 110, such as a plurality of circumferentially distributed bosses or a continuous spiral rib, on the end or connection area of the first part 100. After the first part 100 is completely solidified and shaped, the injection mold core is completely extracted from the mold cavity or transferred to the next station, thereby exposing the formed first part 100 and freeing up space in the original mold cavity for forming the second part 200. At this time, the first part 100 is retained as an insert in the mold system and enters the second injection stage. Then, a second plastic material (such as polyethylene PE) is injected into the injection mold cavity, which melts and flows and coats the designated area of the first part 100, especially fills the gap between the first touch-up portion 110, flows around the protruding structure, and forms a tightly fitted molten layer on its surface. During the cooling and solidification process, the second plastic material physically fuses with the first part 100 at the interface to form a firm integrated structure, and the second touch-up portion 210 that is in concave-convex cooperation with the first touch-up portion 110 is naturally formed. That is, when the first touch-up portion 110 is protruding, the second part 200 forms a corresponding recess. Or, when the first touch-up portion 110 is a recess, the second part 200 forms a protrusion, which resists the pulling force in the axial direction. Not only does it increase the effective bonding area between the two materials, but it also enhances the tensile strength and peel resistance of the connection site through the interfacial engagement, effectively preventing delamination, cracking, or leakage due to vibration, thermal expansion and contraction, or internal pressure fluctuations during long-term use.

[0057] In addition, in some embodiments, if the mold is also provided with a clamping forming structure, a clamping portion 120 (such as a radially extending buckle or a flange) can be synchronously formed at the end of the first part 100, and in the second injection molding process, the molten second plastic material will flow into the gap between the clamping portions 120 and cover the root thereof, further forming a "reverse buckle type" or "riveted type" clamping connection. The entire molding method does not need to rely on subsequent welding or bonding processes.

[0058] Yet another embodiment of the present disclosure provides a pipe connection 300, which is formed by injection molding using the pipe connection mold of any one of the above-mentioned first aspect embodiments. For details, please refer to the above-mentioned first aspect embodiments. Figure 1 、 Figure 2 and Figure 4 In the embodiment, the pipe connection includes a first connection part made of a first plastic material and a second connection part made of a second plastic material. Specifically, in the injection molding process, a first connection part made of PE is first formed between the injection molding cavity and the injection molding core, and the end thereof is provided with a first enhanced touch portion 110 formed directly by the core, such as a circumferentially distributed protrusion, a sawtooth structure or a thread; then the core is removed, and the second injection molding process is started, in which the molten PA material is injected and covers the specified area of the first connection part, and after cooling, the second connection part is formed. In this process, the PA melt fills the grooves of the first enhanced touch portion 110 or flows around the protrusions, and after solidification, the second enhanced touch portion 210 naturally formed with the concave-convex matching is formed, realizing the mechanical interlocking between the interfaces. In addition, if the end of the first connection part is also provided with a clamping portion 120 (such as a radial flange or a buckle).

[0059] Specifically, in some embodiments, the first connection part and the second connection part are both made of plastic, but the selected plastics are different.

[0060] Optionally, the first plastic material can be a nylon material or a polyphenylene ether material.

[0061] The nylon material is preferably an aliphatic nylon such as PA6, PA66, PA12, PA11, PA612, PA610, or a high-performance aromatic nylon such as PPA (polyphthalamide). The nylon material has good toughness, wear resistance and self-lubricating property.

[0062] The polyphenylene ether material includes polyphenylene ether (PPO) or polyphenylene sulfide (PPS), which has higher heat resistance, flame retardance and low water absorption, and is suitable for long-term use in high-temperature or humid environments.

[0063] In order to further improve the comprehensive performance of the above-mentioned materials, the first plastic material can also be a modified material obtained by adding reinforcing fillers to the above-mentioned materials. The reinforcing fillers include at least one of the following materials:

[0064] Glass fiber (GF), significantly improve tensile strength, bending modulus and creep resistance;

[0065] Carbon fiber (CF), reduce density while enhancing strength and improve thermal conductivity and anti-static performance;

[0066] Mineral filler (MD) (such as talc, calcium carbonate, etc.), improve dimensional stability, reduce shrinkage and reduce cost.

[0067] For example, the first connecting part 100 of the connector is made of modified material such as "PA66+GF" or "PPO+MD+GF" by injection molding.

[0068] The second plastic material can be an olefin material or a fluoroplastic material.

[0069] The olefin material includes but is not limited to polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC). Such materials are low in cost, easy to process, and good in chemical stability.

[0070] The fluoroplastic material includes but is not limited to polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and ethylene-tetrafluoroethylene copolymer (ETFE).

[0071] Similarly, the second plastic material can also be modified by adding reinforcing fillers to improve its performance:

[0072] The addition of GF or CF in PP or PE can improve rigidity and indentation resistance to prevent deformation during long-term use.

[0073] The addition of GF or mineral powder in PTFE can improve its wear resistance.

[0074] Preferably, the first plastic material includes PE material, and the second plastic material includes PA material. Specifically, the reason why both connecting parts cannot be made of PE material is that although PE material has excellent welding performance and flexibility, it has low hardness, insufficient rigidity, relatively poor heat resistance and dimensional stability, and is prone to creep, deformation or even leakage in long-term pressure or high-temperature environment, which is not suitable as the overall structural material of the pipeline connector. If both connectors are made of PA (polyamide) material, the overall strength and temperature resistance can be improved, but there are practical manufacturing limitations: the current PA injection molding process is difficult to stably produce large-size PA connectors; at the same time, the cost of PA raw materials is significantly higher than that of PE, and if the whole is used, the manufacturing cost will be greatly increased. Therefore, the split design in the present application is adopted in combination with different materials to make the pipeline connector.

[0075] Further, the first connecting piece corresponds to the connecting pipe 300, and the first plastic material has a lower hardness than the second plastic material. Since the first connecting part needs to be directly connected with the connecting pipe 300, the PE material with low hardness and good flexibility is selected, so as to facilitate hot melt butt joint or socket joint with the connecting pipe 300. The second connecting part is made of PA material, so as to provide sufficient structural strength, rigidity and heat resistance, and has a supporting effect.

[0076] Yet another embodiment of the present disclosure provides a pipe unit, wherein, in the pipe unit, Figure 4 In an embodiment, the pipe unit comprises:

[0077] The pipe connecting piece of any one of the embodiments of the third aspect;

[0078] The connecting pipe 300 fixedly connected with the pipe connecting piece.

[0079] Optionally, the pipe connecting piece and the connecting port of the connecting pipe 300 are socket welded and / or camber welded.

[0080] Specifically, in the pipe unit, Figure 4 In an embodiment, the injection molded joint can include a first type of first connecting part, a first type of second connecting part corresponding to the first type of first connecting part, a second type of first connecting part, and a second type of second connecting part corresponding to the second type of first connecting part. The connecting parts of the corresponding types are selected according to the connection mode of the pipe connecting piece and the connecting pipe 300.

[0081] The above embodiments are only illustrative of the principles and effects of the present disclosure, and are not intended to limit the present disclosure. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea of the present disclosure should be covered by the protection scope of the present disclosure.

Claims

1. A tubing connection mould, characterized in that A pipe connector is formed by a method comprising: an injection mold cavity; an injection mold core arranged in the injection mold cavity, the injection mold cavity defining a first injection space for injection molding a first part with a first plastic material, the injection mold core being provided with a touch-up molding structure for molding a first touch-up portion on the first part, and the injection mold core being arranged to be removed from the injection mold cavity after the first part is molded, so that the injection mold cavity allows a second part to be molded with a second plastic material, the second part being integrally formed with the first part and naturally forming a second touch-up portion that is in a concave-convex fit with the first touch-up portion, and the first part and the second part being integrally formed into the pipe connector.

2. The tubing connection mold of claim 1, wherein, The touch-up molding structure comprises a concave-convex structure arranged in a circumferential direction on an outer side of the injection mold core, or a thread structure extending in a circumferential direction on the outer side of the injection mold core.

3. The tubing connection mold of claim 1, wherein, The injection mold is further provided with a clamping molding structure for molding a clamping portion on the first part, the clamping portion being molded at an opening of the first part facing the second part, and the clamping portion extending into the injection mold cavity of the second part, so that the second plastic material can flow into gaps between the clamping portions for clamping connection of the molded first part and the second part.

4. A method of injection molding a pipe coupling, characterized by, The injection molding method comprises: arranging the injection mold core in the injection mold cavity, so that a first injection space is defined between the injection mold core and the injection mold cavity, and the touch-up molding structure of the injection mold core is located in the first injection space; injecting the first plastic material into the first injection space, and allowing the first plastic material to solidify to form the first part, and the first touch-up portion being formed on the first part by the touch-up molding structure; after the first part is solidified, removing the injection mold core from the injection mold cavity, so that a space for injecting the second plastic material is formed in the injection mold cavity; injecting the second plastic material into the injection mold cavity, and allowing the second plastic material to fuse with the first part and solidify to form the second part, the second part being integrally formed with the first part, and the second touch-up portion being naturally formed on the second part in a concave-convex fit with the first touch-up portion, and the first part and the second part together forming the pipe connector.

5. A pipe connection, characterized in that The pipe connector is formed by the injection mold of any one of claims 1-3, and comprises a first connector made of a first plastic material and a second connector made of a second plastic material.

6. The plumbing connection of claim 5, wherein, The first plastic material comprises at least one of the following: nylon material, polyphenyl ether material; The second plastic material comprises at least one of the following: olefin material, fluoroplastic material.

7. The plumbing connection of claim 5, wherein, The first connector corresponds to a pipe, and the hardness of the first plastic material is lower than that of the second plastic material.

8. A duct unit characterized by, The pipe connector comprises: at least one pipe connector of any one of claims 5-7; a pipe fixedly connected with the pipe connector.

9. The duct unit according to claim 8, characterized in that The pipe connector and the connecting port of the pipe are connected by socket welding and / or camber welding.

10. The duct unit of claim 8, wherein, The material hardness of one end of the pipe connector connected with the pipe is lower than that of the other end of the pipe connector.

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