Injection molding die and process for a composite insulator

Abstract

The application discloses an injection molding die and process of a composite insulator, which comprises an upper die and a lower die, an upper die core is arranged in the upper die, and a lower die core is arranged in the lower die; a core rod accommodating cavity and a plurality of umbrella skirt grooves are arranged in the upper die core and the lower die core, the core rod accommodating cavity and the plurality of umbrella skirt grooves are communicated, during pouring, a core rod is placed in the core rod accommodating cavity between the upper die core and the lower die core, both ends of the core rod are supported through a first lifting device, and the upper surface of the upper die is connected with a second lifting device; the upper die core and the lower die core are detachably arranged on the upper die and the lower die respectively, the upper die core and the lower die core can be replaced according to needs, and the composite insulator with different forms of umbrella skirts can be prepared; in addition, through the first lifting device and the second lifting device, the prepared composite insulator can be automatically demolded, manual demolding with a crowbar is not needed, and damage to the die core is avoided.

Description

Technical Field

[0001] This invention relates to the field of insulator injection molding technology, specifically to an injection molding mold and process for composite insulators. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Insulators play two basic roles in overhead transmission lines: supporting the conductors and preventing current from returning to the ground. Early insulators were usually made of glass or ceramic. Later, composite insulators appeared, which consist of a glass fiber resin core rod (or core tube) and an organic material sheath and skirts. Composite insulators have advantages such as light weight, high strength, not easy to break, high flashover voltage, and easy to manufacture, transport and maintain.

[0004] The preparation process of composite insulator skirts typically uses injection molding in conjunction with a mold. Existing molds include an upper mold and a lower mold, with internal gates and runners. The two molds work together to form an injection cavity. For example, Chinese invention patent CN110767396B discloses a suspension superhydrophobic insulator molding mold. However, this mold has the following problems: 1. The upper and lower molds are integral parts, and the size and spacing of the skirt grooves are fixed, allowing only one type of composite insulator skirt to be processed; 2. When the product is removed from the mold, the skirt adheres to the mold, requiring manual prying to remove the core rod with the injected skirt and skirt. This prying process causes invisible damage to the core rod, affecting the long-term mechanical properties of the product. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an injection molding mold and process for composite insulators, which can prepare various types of sheds, and also has the function of precise positioning and demolding of the core rod.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the invention, an injection molding die for a composite insulator is provided, comprising an upper die and a lower die, wherein an upper die core is disposed in the upper die and a lower die core is disposed in the lower die; a mandrel receiving cavity and a plurality of skirt grooves are disposed in the upper die core and the lower die core, the mandrel receiving cavity and the plurality of skirt grooves being connected; during casting, a mandrel is placed in the mandrel receiving cavity between the upper die core and the lower die core; both ends of the mandrel are supported by a first lifting device; the upper surface of the upper die is connected to a second lifting device; automatic demolding is achieved by the first lifting device and the second lifting device.

[0008] In some embodiments of the present invention, the upper mold and the upper mold core are provided with a plurality of glue injection channels, which are connected to the core rod receiving cavity and the umbrella skirt groove.

[0009] In some embodiments of the present invention, the lower mold and the first lifting device are disposed on the base plate, and the second lifting device is disposed on both sides of the lower mold and corresponds to the mandrel receiving cavity.

[0010] In some embodiments of the present invention, a fixing sleeve is provided at the upper end of the first lifting device, and the fixing sleeve is sleeved on both ends of the mandrel.

[0011] In some embodiments of the present invention, the first lifting device is mounted on the base plate via a slide groove, and the first lifting device is capable of moving laterally along the slide groove.

[0012] In some embodiments of the present invention, the upper mold core is mounted on the upper mold by bolts, and the lower mold core is mounted on the lower mold by locating pins and locating holes. Both the upper mold core and the lower mold core are detachable.

[0013] In some embodiments of the present invention, the second lifting device is mounted on a top plate, and the top plate is supported by a first support provided on a cover plate.

[0014] In some embodiments of the invention, the cover plate is supported by a second support provided on the base plate.

[0015] In a second aspect of the present invention, an injection molding process for a composite insulator is provided, comprising the following steps:

[0016] The polished mandrel is wrapped with carbon fiber cloth as the wrapping material to form a wrapping part. The wrapping part is then vacuum impregnated with phenolic epoxy resin to obtain a resin ring.

[0017] The processed mandrel is placed in the mandrel receiving cavity between the upper and lower mold cores and fixed by a fixing sleeve. The upper and lower mold cores are then brought into close contact by a second lifting device.

[0018] Silicone rubber is injected into the mandrel receiving cavity and multiple umbrella skirt grooves through the injection channel;

[0019] After the sheath and skirt are formed, the upper mold and upper mold core are lifted by the first lifting device, and the formed composite insulator is lifted by the second lifting device to complete the demolding.

[0020] After the anodized metal fittings are fitted onto both ends of the mandrel, glue is injected to bond them together, forming a finished insulator.

[0021] In some embodiments of the present invention, different types of upper and lower mold cores are replaced as needed before injection.

[0022] One or more technical solutions of the present invention have the following beneficial effects:

[0023] (1) The injection molding mold for composite insulators provided by the present invention has an upper mold core and a lower mold core installed on the upper mold and the lower mold respectively in a detachable manner. The upper mold core and the lower mold core can be replaced as needed, and composite insulators with different types of sheds can be produced, which increases the applicability of the mold.

[0024] (2) The injection molding mold for composite insulators provided by the present invention can automatically demold the prepared composite insulators by means of the cooperation of the first lifting device and the second lifting device, without the need for manual demolding with a pry bar, thus avoiding damage to the mold core.

[0025] (3) The injection molding mold for composite insulators provided by the present invention has a sleeve on the first lifting device, which can provide stable support for the core rod, and the first lifting device can also adjust the position according to the length of the core rod.

[0026] (4) The injection molding mold for composite insulators provided by the present invention has a simple structure, is easy to use, and has a wide range of applications, and can meet the needs of preparing different composite insulators.

[0027] (5) The preparation process provided by the present invention involves pressure injection molding of silicone rubber sheds on the outer surface of the resin ring and the core rod to obtain an insulator, which can effectively alleviate the cracking of the core rod when subjected to end face stress impact and thermal stress impact, and can prevent crack propagation when the core rod has cracked, and ensure that it still has good structural strength and electrical breakdown resistance. Attached Figure Description

[0028] Figure 1 This is a front sectional view of the injection molding die for the composite insulator of the present invention;

[0029] Figure 2 This is a left sectional view of the injection molding die for the composite insulator of the present invention;

[0030] Figure 3 A composite insulator prepared by the injection molding die of the present invention;

[0031] Figure 4 Another form of composite insulator prepared by the injection molding mold of the present invention.

[0032] In the diagram: 1. Upper mold; 2. Upper mold core; 3. First lifting device; 4. Slide groove; 5. Base plate; 6. Lower mold; 7. Lower mold core; 8. Fixing sleeve; 9. Core rod; 10. Bolt; 11. Injection channel; 12. Top plate; 13. First support column; 14. Second lifting device; 15. Second support column; 16. Cover plate; 17. Protective sleeve; 18. Umbrella skirt. Detailed Implementation

[0033] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] Example 1

[0035] In a typical embodiment of the present invention, an injection molding die for a composite insulator is provided, such as... Figure 1 and Figure 2 As shown, the injection molding die includes an upper die 1 and a lower die 6. An upper die core 2 is provided inside the upper die 1, and a lower die core 7 is provided inside the lower die 6. Both the upper die core 2 and the lower die core 7 are detachably installed in the upper die 1 and the lower die 6, respectively. Specifically, the upper die core 2 is installed on the upper die 1 by bolts 10, and the lower die core 7 is installed on the lower die 6 by positioning pins and positioning holes. The detachable nature of the upper die core 2 and the lower die core 7 allows for quick replacement. Since the actual application scenarios of composite insulators are different, the size, form, and spacing between adjacent sheds of composite insulators are also different. The required upper die core 2 and lower die core 7 can be replaced according to actual needs, and different composite insulators can be prepared on the same mold.

[0036] The upper mold core 2 and the lower mold core 7 are provided with a mandrel receiving cavity and multiple umbrella skirt grooves. The mandrel receiving cavity and the multiple umbrella skirt grooves are connected. The mandrel receiving cavity of the upper mold core 2 and the mandrel receiving cavity of the lower mold core 7 are both semi-cylindrical cavity structures. When the upper mold core 2 and the lower mold core 7 are mated and fitted, they form an integral cylindrical cavity for placing the mandrel 9. The upper mold 1 and the upper mold core 2 are provided with a connected glue injection channel 11. The glue injection channel 11 is connected to the mandrel receiving cavity and the umbrella skirt grooves. The glue injection channel 11 is connected to the injection machine through an injection tube to realize the injection of glue into the mandrel receiving cavity and the umbrella skirt grooves. In order to improve the glue injection efficiency and glue injection uniformity, multiple glue injection channels 11 are provided, preferably two. The glue injection channels 11 should be staggered from the umbrella skirt grooves.

[0037] In this embodiment, the shed grooves on the upper mold core 2 and the lower mold core 7 can be configured in different forms, such as successively decreasing diameters of the shed grooves, different shed groove spacings, different numbers of shed grooves, and different spacings, thereby preparing composite insulators with different shed skirt forms, such as... Figure 3and Figure 4 As shown, the outer surface of the core rod 9 is covered with a sheath 17, and the sheath 17 is provided with umbrella skirts 18 of different sizes, wherein, Figure 3 The design alternates between large and small umbrella-shaped skirts. Figure 4 The diameter of the umbrella skirt 18 decreases sequentially.

[0038] In order to support the core rod 9, a first lifting device 3 is provided at each end of the core rod 9. A fixing sleeve 8 is provided at the upper end of the first lifting device 3. The fixing sleeve 8 is sleeved on both ends of the core rod 9 to fix the core rod 9 during the glue injection process. The first lifting device 3 can also lift the core rod 9 after glue injection molding to realize the demolding of the composite insulator.

[0039] In this embodiment, the injection mold is set on the base plate 5. The injection mold consists of a lower mold 6, a lower mold core 7, an upper mold core 2, and an upper mold 1 from bottom to top. The lower mold 6 is detachably connected to the base plate 5. The first lifting device 3 is set on the base plate 5. The first lifting device 3 is located on the left and right sides of the lower mold 6 and corresponds to the mandrel receiving cavity. The first lifting device 3 is installed on the base plate 5 through a slide groove 4. The first lifting device 3 can move laterally along the slide groove 4 to accommodate mandrels of different lengths.

[0040] The upper surface of the upper mold 1 is also connected to the second lifting device 14. Under the action of the second lifting device 14, the upper mold 1 and the upper mold core 2 can be moved up and down to achieve the fitting and separation of the upper mold core 2 and the lower mold core 7. The second lifting device 14 is installed on the top plate 12. The top plate 12 is supported by a plurality of first pillars 13 set on the cover plate 16. The cover plate 16 is supported by a plurality of second pillars 15 set on the bottom plate 5.

[0041] In some embodiments of this example, the first lifting device 3 and the second lifting device 14 can be implemented using hydraulic cylinders to achieve the lifting function.

[0042] The method of using the injection mold provided in this embodiment is as follows:

[0043] Select appropriate upper mold core 2 and lower mold core 7 according to actual production needs, and install them on upper mold 1 and lower mold 6 respectively. Grind the formed core rod 9 to increase its surface contact area with the rubber material and improve the bonding performance. Raise the second lifting device 14 to separate the upper mold core 2 and lower mold core 7. Place the ground core rod 9 in the core rod receiving cavity between the upper mold core 2 and lower mold core 7 and fix it with the fixing sleeve 8. Lower the second lifting device 14 to make the upper mold core 2 and lower mold core 7 fit tightly. Connect the glue injection channel 11, glue injection tube and glue injection machine in sequence. Inject silicone rubber into the core rod receiving cavity and multiple umbrella skirt grooves through the glue injection channel 11. After the sheath 17 and umbrella skirt 18 are formed, raise the upper mold 1 and upper mold core 2 through the second lifting device 14 and raise the formed composite insulator through the first lifting device 3 to complete the demolding.

[0044] The injection mold provided in this embodiment allows the upper mold core 2 and the lower mold core 7 to be detachably installed on the upper mold 1 and the lower mold 6, respectively. The upper mold core 2 and the lower mold core 7 can be replaced as needed to produce composite insulators with different types of sheds. In addition, the first lifting device 3 and the second lifting device 14 can automatically demold the prepared composite insulator without the need for manual demolding with a pry bar, thus avoiding damage to the mold core.

[0045] Example 2

[0046] In a typical embodiment of the present invention, a process for preparing a composite insulator is provided, comprising the following steps:

[0047] The polished mandrel 9 is wrapped with carbon fiber cloth as the wrapping material to form a wrapping part. The wrapping part is vacuum impregnated with phenolic epoxy resin to obtain a resin ring.

[0048] The processed mandrel is placed in the mandrel receiving cavity between the upper mold core 2 and the lower mold core 7, and fixed by the fixing sleeve 8. The upper mold core 2 and the lower mold core 7 are tightly attached by the first lifting device 3.

[0049] Silicone rubber is injected into the mandrel receiving cavity and multiple umbrella skirt grooves through the injection channel 11;

[0050] After the sheath 17 and the umbrella skirt 18 are formed, the upper mold 1 and the upper mold core 2 are lifted by the first lifting device 3, and the formed composite insulator is lifted by the second lifting device 14 to complete the demolding.

[0051] After the anodized metal fittings are fitted onto both ends of the mandrel, glue is injected to bond them together, forming a finished insulator.

[0052] In this embodiment, the carbon fiber cloth is composed of glass fiber and aromatic polyoxadiazole fiber, with a mass ratio of glass fiber to modified aromatic polyoxadiazole fiber of 2:1. The carbon fiber cloth provides the core rod 3 with resistance to thermal stress impact and provides stress buffering performance under end-face impact conditions. The aromatic polyoxadiazole fiber, with its main chain containing alternating benzene and oxadiazole rings, forms a rigid conjugated molecular structure. The macromolecular chain exhibits a rigid rod-like shape, giving the modified aromatic polyoxadiazole fiber itself good thermal stability, chemical resistance, and electrical insulation properties, and also providing excellent reinforcement for the glass fiber. The 2:1 mass ratio of glass fiber to modified aromatic polyoxadiazole fiber in the carbon fiber cloth results in a blended fiber cloth with excellent structural retention properties.

[0053] In this embodiment, the vacuum impregnation process is performed in three stages. After each impregnation is completed, the sample is left to stand for a set time before the next vacuum impregnation is performed. This process is repeated three times to complete the process, and then a resin ring covering the wrapping section is obtained on the surface of the corresponding wrapping section.

[0054] In some embodiments of this example, before injection, different types of upper mold core 2 and lower mold core 7 are replaced as needed.

[0055] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An injection molding die for a composite insulator, characterized in that, The system includes an upper mold and a lower mold. The upper mold contains an upper mold core, and the lower mold contains a lower mold core. The upper mold core and the lower mold core each contain a mandrel receiving cavity and multiple umbrella skirt grooves. The mandrel receiving cavity and the multiple umbrella skirt grooves are connected. During casting, the mandrel is placed in the mandrel receiving cavity between the upper mold core and the lower mold core. The two ends of the mandrel are supported by a first lifting device. The upper surface of the upper mold is connected to a second lifting device. Automatic demolding is achieved through the first lifting device and the second lifting device. The lower mold and the first lifting device are mounted on the base plate; The first lifting device is mounted on the base plate via a slide rail, and the first lifting device can move laterally along the slide rail; The upper mold core is mounted on the upper mold by bolts, and the lower mold core is mounted on the lower mold by positioning pins and positioning holes. Both the upper mold core and the lower mold core are detachable. The first lifting device is located on both sides of the lower mold and corresponds to the mandrel receiving cavity; A fixed sleeve is provided at the upper end of the first lifting device, and the fixed sleeve is sleeved on both ends of the mandrel.

2. The injection molding die for the composite insulator as described in claim 1, characterized in that, The upper mold and the upper mold core are provided with multiple glue injection channels, which are connected to the core rod receiving cavity and the umbrella skirt groove.

3. The injection molding die for the composite insulator as described in claim 1, characterized in that, The second lifting device is installed on the top plate, which is supported by a first support column set on the cover plate.

4. The injection molding die for the composite insulator as described in claim 3, characterized in that, The cover plate is supported by a second support set on the base plate.

5. The injection molding die for the composite insulator as described in claim 1, characterized in that, Before injection, different types of upper and lower mold cores can be replaced as needed.

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