A production mold for an electrical insulation part

Abstract

The application provides a production mold of an electric insulation part and belongs to the technical field of molds. The problem of low production efficiency and low product quality is solved. The mold comprises an upper mold, a lower mold and a lower core-pulling mechanism fixed on the lower mold. The lower core-pulling mechanism is externally provided with a forming part, and the outer side of the forming part is provided with a forming part for forming an inner creepage umbrella skirt. The forming part is provided with a sleeve joint hole, the forming part is sleeved on the outside of the lower core-pulling mechanism through the sleeve joint hole, the lower core-pulling mechanism can be pulled out from the sleeve joint hole downwards, the forming part is elastic, and the inner wall of the forming part is tightly abutted against the outer wall of the lower core-pulling mechanism under the action of the elastic force of the forming part. The mold has the advantages of high production efficiency and high product quality.

Description

Technical Field

[0001] This invention belongs to the field of mold technology, and relates to production molds for electrical insulation parts, and more particularly to production molds for contact boxes. Background Technology

[0002] High-voltage switchgear generally includes a switchgear body and components such as contact boxes, bent partitions, and bushings housed within the switchgear body. The contact box is an insulating component; its function is to insulate the connection between incoming and outgoing lines, ensuring the safe operation of the high-voltage switchgear. The contact box typically consists of a cylindrical body made of insulating material, with an inlet and an outlet end. Creepage skirts (comprising several annular protrusions distributed along the axial direction of the body) are provided on the sides of the body to increase creepage distance. Currently, contact boxes are primarily formed using a mold with liquid epoxy resin through a casting process. The mold includes an upper mold with a cavity and a plate-shaped lower mold (also called a lower template). The upper mold includes a stationary mold and a moving mold, and the cavity is formed by assembling the stationary and moving molds. A lower core is fixed on the lower mold. When the lower mold abuts against the bottom of the upper mold, the lower core extends into the cavity of the upper mold, and the upper mold, lower mold, and lower core together form an injection cavity. The lower mold has an injection hole communicating with the injection cavity. During molding, liquid epoxy resin material is injected into the injection cavity through the injection hole. After the liquid epoxy resin material cures, it will be molded into a contact box.

[0003] In the existing contact box molding process, if the contact box needs to have an outer creepage skirt (i.e., located on the outside of the contact box), the corresponding structure is set on the stationary mold of the upper mold; if the contact box needs to have an inner creepage skirt (i.e., located on the inside of the contact box), the first method is to fix an annular connector with an inner creepage skirt inside the molded contact box, but this method has poor overall integrity and a high scrap rate; the second method is to set a molding part on the outside of the lower core pull, and the outside of the molding part has a molding part that can be injected with liquid epoxy resin material and can be formed into an inner creepage skirt after the liquid epoxy resin is cured. Specifically, in the second method, since the creepage umbrella skirt inside the molded contact box is embedded with the molded part outside the molded part, in order to achieve smooth demolding, the molded part is set to be spliced ​​together by several metal pieces attached to the side of the lower core pull (refer to the inverted injection production method of the solidified pole disclosed in patent application number 201810478263.1). The liquid epoxy resin in the injection cavity is cured and molded into a contact box. First, the lower mold pulls the lower core pull out from the upper mold to make room inside the molded part. Then, the workers take out each metal piece from the molded contact box in turn. However, in real-world environments, gaps inevitably exist at the joints of the metal sheets, and gaps also inevitably exist between the metal sheets and the lower core. As a result, liquid epoxy resin material will inevitably seep into these gaps and, after curing, form excess material inside the contact box. This significantly increases the time required to clean the inside of the contact box, affecting production efficiency. Furthermore, it is very easy to generate burrs or flash (the presence of burrs or flash can cause point discharge inside the contact box during use, posing a safety hazard) and resulting in poor product quality.

[0004] To address the issue of poor product quality caused by gaps between metal sheets and between metal sheets and the lower core, those skilled in the art can easily conceive of improving the fit between the metal sheets and between the metal sheets and the lower core. For example, a complete metal forming part can be machined first, and then the metal forming part can be precisely cut into several metal sheets to ensure the fit between the metal sheets. At the same time, the inner walls of each metal sheet can be finely machined according to the outer wall of the lower core to improve the fit between the metal sheets and the lower core. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a production mold for electrical insulation components, which solves the problems of low production efficiency and poor product quality.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A production mold for an electrical insulation component includes an upper mold, a lower mold, and a lower core fixed on the lower mold. The lower core is provided with a molding part, and the outer side of the molding part has a molding portion for molding an inner creepage skirt. The molding part is characterized in that it has a sleeve hole, the molding part is sleeved on the lower core through the sleeve hole, and the lower core can be dislodged downward from the sleeve hole. The molding part is elastic, and its inner wall is in close contact with the outer wall of the lower core under its own elastic force.

[0008] Similar to traditional molds used for producing contact boxes, when producing contact boxes, the lower mold moves to allow the lower core to extend into the upper mold. The lower mold abuts against the bottom of the upper mold, forming an injection cavity between the lower mold, the upper mold, and the lower core. Liquid epoxy resin material is injected into the injection cavity, and after the liquid epoxy resin material cures, it will be formed into a contact box (due to the presence of the molding part on the molded part, the interior of the contact box will be integrally formed with an internal umbrella skirt).

[0009] In this mold, the molding part is directly sleeved outside the lower core pull, and the inner wall of the molding part is tightly fitted with the outer wall of the lower core pull under the action of its own elastic deformation force. On the one hand, the molding part is an integral structure without gaps, and on the other hand, there are almost no gaps between the molding part and the lower core pull due to the tight fit. As a result, there is almost no excess material inside the molded contact box, which greatly saves the time of the workers to clean the inside of the contact box and improves production efficiency. At the same time, this also means that the existence of burrs or flash is reduced, thus improving the quality of the product.

[0010] In addition, after molding is completed, the core puller is pulled out of the upper mold by the lower mold plate. The workers can use the deformation ability of the molded part to directly remove the molded part from the contact box after molding, which also improves production efficiency to a certain extent (the metal sheets in the existing technology need to be removed one by one after molding).

[0011] In the aforementioned production mold for electrical insulation components, the lower template has a positioning cavity, the lower end of the lower core puller is located inside the positioning cavity, and the lower end of the molded part has a gripping part embedded in the positioning cavity.

[0012] After molding is completed, the lower mold drives the lower core puller to detach from the upper mold. At this time, the gripping part is located outside the lower end of the molded contact box. The operator can easily and quickly pull the entire molded part out of the molded contact box through the gripping part, which improves production efficiency.

[0013] In the aforementioned production mold for electrical insulation components, the outer wall of the gripping part is a conical surface with an outer diameter that gradually decreases from top to bottom.

[0014] The above settings make it easier for the entire molded part to deform from the gripping part inwards, further improving production efficiency.

[0015] In the production mold of the aforementioned electrical insulation components, a positioning structure is provided between the gripping part and the lower core puller, which positions the two along the axial direction of the lower core puller by means of a concave-convex engagement.

[0016] The positioning structure allows the molded part to be positioned axially along the lower core pull, ensuring that the molded part will not slide upwards under the pressure of liquid epoxy resin when it is injected into the injection cavity, thus guaranteeing the reliability of the molding process and the quality of the molded product. Furthermore, the positioning structure, with its gripping part positioned closer to the lower end of the molded part, reduces the time of resistance generated when the lower core pull is ejected from the molded part, thereby facilitating demolding.

[0017] In the production mold of the aforementioned electrical insulation components, the positioning structure includes an annular positioning groove located inside the gripping part and a positioning protrusion located on the lower core-pulling side, with the positioning protrusion embedded in the annular positioning groove.

[0018] In the production mold of the aforementioned electrical insulation components, as another technical solution, the positioning structure includes an annular positioning part located inside the gripping part and an annular groove located on the lower core-pulling side, with the annular positioning part embedded in the annular groove.

[0019] In the production mold of the aforementioned electrical insulation components, the molded parts are made of high-temperature resistant silicone rubber.

[0020] High-temperature resistant silicone rubber not only has good elastic deformation ability, but also good high-temperature resistance. It can ensure that the silicone rubber is not affected while the liquid epoxy resin material is cured and formed into a contact box by heating the mold, thus ensuring product quality during long-term production.

[0021] In the production mold of the aforementioned electrical insulation component, the forming part includes several annular protrusions arranged axially along the lower core, and an annular groove is formed between two adjacent annular protrusions, with the bottom wall of the annular groove being a circular arc surface.

[0022] After the liquid epoxy resin material is injected into the injection cavity, it will fill each annular groove. Then, after the liquid epoxy resin material filling each annular groove is cured, it will directly form the inner umbrella skirt of the contact box.

[0023] In the aforementioned mold for producing electrical insulation components, the molded part is a cylindrical shape with a closed top.

[0024] In the aforementioned production mold for electrical insulation components, as another technical solution, the molded part is a circular sleeve with openings at both ends.

[0025] Whether the molded part is a closed-top cylindrical shape or a circular sleeve shape with open ends, it can be guaranteed that the molded part can be directly fitted onto the lower core and form a tight abutment with the outer wall of the lower core under its own elastic force.

[0026] Compared with existing technologies, the production mold for this electrical insulation component features a ring-shaped cross-section that allows for elastic deformation. This enables the molded part to be directly fitted onto the lower core and to form a tight fit with the outer wall of the lower core using its own elasticity. On the one hand, the molded part is a monolithic structure without gaps; on the other hand, the molded part and the lower core are also tightly fitted with almost no gaps. As a result, the interior of the formed contact box will have almost no excess material, greatly saving the time that workers would otherwise spend cleaning the interior of the contact box. Furthermore, workers will not need to assemble the molded part by splicing multiple metal sheets during subsequent production, improving production efficiency. This also means that the presence of burrs or flash is reduced, thus improving product quality.

[0027] In addition, workers can also use the deformation capacity of the molded parts to achieve overall demolding of the molded parts, which further improves production efficiency. Attached Figure Description

[0028] Figure 1 This is a longitudinal sectional view of the first embodiment of the production mold for this electrical insulation component.

[0029] Figure 2 This is an exploded schematic diagram of the production mold of this electrical insulation component, according to Embodiment 1.

[0030] Figure 3 This is a longitudinal sectional view between the molded part and the lower core puller in Example 1.

[0031] Figure 4 This is a schematic diagram of the molded part in Example 1.

[0032] Figure 5 This is a schematic diagram of the molded part from another angle in Embodiment 1.

[0033] Figure 6 This is a schematic diagram of the core pulling process in Example 1.

[0034] Figure 7 This is a schematic diagram showing the contact box produced using the production mold of this electrical insulation component.

[0035] In the diagram, 1. Upper mold; 1a. Static mold; 1b. Moving mold; 1c. Injection hole; 2. Lower mold; 2a. Positioning cavity; 3. Lower core puller; 3a. Positioning protrusion; 3b. Protrusion 1; 3c. Protrusion 2; 4. Molded part; 4a. Molded part; 4a1. Annular protrusion; 4a2. Annular groove; 4b. Gripping part; 4b1. Annular positioning groove; 4c. Limiting hole 1; 4d. Limiting hole 2; 4e. Socket hole; 5. Connector; 6. Metal insert; 7. Injection cavity; 8. Insert. Detailed Implementation

[0036] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0037] Example 1

[0038] like Figure 1 and Figure 2 As shown, the production mold for electrical insulation components includes an upper mold 1, a lower mold 2, and a lower core 3 fixed on the upper mold 1. The upper mold 1 has a cavity penetrating the bottom of the upper mold 1. The lower mold 2 can move up and down to allow the lower core 3 to extend into or out of the cavity of the upper mold 1. After the lower mold 2 drives the lower core 3 into the cavity of the upper mold 1, the lower mold 2 seals the opening of the cavity of the upper mold 1, forming an injection cavity 7 between the upper mold 1, the lower mold 2, and the lower core 3. The upper mold 1 includes a stationary mold 1a and a moving mold 1b. The injection cavity 7 is formed by combining the stationary mold 1a and the moving mold 1b. The side of the upper mold 1 has an injection hole 1c that communicates with the injection cavity 7. The connection between the injection hole 1c and the injection cavity 7 is located near the opening of the cavity of the upper mold 1. An insert 8 is also fixed inside the stationary mold 1a, and part of the insert 8 is located inside the injection cavity 7.

[0039] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, a molding part 4 is provided outside the lower core 3, and the outer side of the molding part 4 has a molding portion 4a for molding the inner creepage umbrella skirt. The molding part 4 has a sleeve hole 4e, through which the molding part 4 is sleeved on the lower core 3. The lower core 3 can be pulled out downward from the sleeve hole 4e. The molding part 4 is elastic, and its inner wall is in close contact with the outer wall of the lower core 3 under its own elastic force. In this embodiment, the molding part 4 is made of silicone rubber. The molding portion 4a includes several annular protrusions 4a1 arranged along the axial direction of the lower core 3. An annular groove 4a2 is formed between two adjacent annular protrusions 4a1, and the bottom wall of the annular groove 4a2 is an arc surface. The lower mold plate 2 has a positioning cavity 2a. The lower end of the lower core 3 is located in the positioning cavity 2a, and the lower end of the molding part 4 has a gripping portion 4b embedded in the positioning cavity 2a. The outer wall of the gripping portion 4b is a conical surface with an outer diameter that gradually decreases from top to bottom. The gripping part 4b is embedded in the positioning cavity 2a, meaning it is not inside the injection cavity 7. Therefore, after the lower mold 2 drives the lower core puller 3 to exit from the upper mold 1, the gripping part 4b is located outside the lower end of the formed contact box. Workers can easily and quickly pull the entire formed part 4 out of the formed contact box using the gripping part 4b, improving production efficiency. In this embodiment, the forming part 4a is located above and close to the gripping part 4b.

[0040] Furthermore, such as Figure 3 As shown, a positioning structure is provided between the gripping part 4b and the lower core puller 3, which engages in a concave-convex manner to position them along the axial direction of the lower core puller 3. The positioning structure includes an annular positioning groove 4b1 located inside the gripping part 4b and a positioning protrusion 3a located on the side of the lower core puller 3, with the positioning protrusion 3a embedded in the annular positioning groove 4b1. By providing the positioning structure, the molded part 4 and the lower core puller 3 can be positioned along the axial direction of the lower core puller 3, ensuring that the molded part 4 will not slide upward under the pressure of the liquid epoxy resin injected into the injection cavity 7, thus guaranteeing the reliability of the molding process and the quality of the molded product.

[0041] In this embodiment, as Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, the upper end of the molded part 4 is closed and cylindrical. A connector 5 is fixed at the top center of the lower core 3. The connector 5 extends out of the upper end of the molded part 4. A metal insert 6 is connected to the connector 5 extending out of the upper end of the molded part 4, and the two are interference-fitted. The top of the lower core 3 also has a protrusion 3b and a protrusion 3c. The upper end of the molded part 4 has a through-hole 4c and a through-hole 4d. The protrusion 3b is inserted into the through-hole 4c, and the outer wall of the protrusion 3b is in close contact with the inner wall of the through-hole 4c. The protrusion 3c is inserted into the through-hole 4d, and the outer wall of the protrusion 3c is in close contact with the inner wall of the through-hole 4d. Both the protrusion 3b and the protrusion 3c are flush with the upper end surface of the molded part 4. The inner wall of the molded part 4 is tightly fitted with the outer wall of the lower core puller 3 under its own elastic force. Basically, the molded part 4 will not rotate relative to the lower core puller 3. However, through the cooperation of the protrusion 3b and the limiting hole 4c, and the cooperation of the protrusion 3c and the limiting hole 4d, the rotation of the molded part 4 can be completely prevented when the liquid epoxy resin material is injected into the injection cavity 7, thus ensuring product quality.

[0042] Similar to traditional molds used for producing contact boxes, when producing contact boxes, the moving mold 1b and the stationary mold 1a are assembled to form the upper mold 1. The lower mold 2 moves upward, causing the lower core puller 3 to extend into the upper mold 1. The lower mold 2 abuts against the bottom of the upper mold 1, forming an injection cavity 7 between the lower mold 2, the upper mold 1, and the lower core puller 3. Then, liquid epoxy resin material is injected into the injection cavity 7 through the injection hole 1c. Figure 7 As shown, after the liquid epoxy resin material cures, it will form a contact box. The liquid epoxy resin material will also fill each annular groove 4a2 and, after curing, form the inner creepage skirt of the contact box. In this mold, since the molded part 4 is fitted outside the lower core 3 and its inner wall forms a tight abutment with the outer wall of the lower core 3 under its own elastic deformation force, this means that, on the one hand, the molded part 4 itself is a monolithic structure without gaps; on the other hand, there are almost no gaps between the molded part 4 and the lower core 3 due to their tight fit. As a result, the inside of the molded contact box will have almost no excess material, greatly saving the time for subsequent cleaning of the inside of the contact box, improving production efficiency, and also reducing the presence of burrs or flash, thus improving product quality.

[0043] After molding is complete, the lower mold 2 moves downwards. Since the inner creeping umbrella skirt of the molded contact box is embedded with the molding part 4a outside the molded part 4, the lower core puller 3 will directly eject from the upper mold 1 as the lower mold 2 moves downwards, while the molded part 4 remains inside the upper mold 1. Then, the operator can use the deformation capability of the molded part 4 to directly remove it from the molded contact box. The molded part 4 is removed as a whole, greatly saving demolding time and improving production efficiency to some extent. Finally, the moving mold 1b separates from the stationary mold 1a, and the operator completes the final demolding of the molded contact box.

[0044] Example 2

[0045] The structure and principle of this embodiment are basically the same as those of Embodiment 1. The difference is that in this embodiment, the positioning structure includes an annular positioning part located inside the gripping part 4b and an annular groove 4a2 located on the side of the lower core 3. The annular positioning part is embedded in the annular groove 4a2.

[0046] Example 3

[0047] The structure and principle of this embodiment are basically the same as those of Embodiment 1. The difference is that in this embodiment, the molded part 4 is a circular sleeve with openings at both ends.

[0048] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A production mold for an electrical insulation component, comprising an upper mold (1), a lower mold (2), and a lower core puller (3) fixed on the lower mold (2), wherein an injection cavity (7) is formed between the upper mold (1), the lower mold (2), and the lower core puller (3), wherein a molding part (4) is provided outside the lower core puller (3), and the molding part (4) has a molding portion (4a) on its outer side for molding an inner creepage umbrella skirt, characterized in that, The molded part (4) has a sleeve hole (4e). The molded part (4) is sleeved on the lower core (3) through the sleeve hole (4e) and the lower core (3) can be pulled out downward from the sleeve hole (4e). The molded part (4) is elastic and its inner wall is in close contact with the outer wall of the lower core (3) under its own elastic force. The lower end of the molded part (4) has a gripping part (4b). The gripping part (4b) extends out of the injection cavity (7). The outer wall of the gripping part (4b) is a conical surface with an outer diameter that gradually decreases from top to bottom. A positioning structure is provided between the gripping part (4b) and the lower core (3) to position them along the axial direction of the lower core (3) by means of a concave-convex cooperation.

2. The production mold for electrical insulation components according to claim 1, characterized in that, The lower mold (2) has a positioning cavity (2a), the lower end of the lower core puller (3) is located in the positioning cavity (2a), and the gripping part (4b) is embedded in the positioning cavity (2a).

3. The production mold for electrical insulation components according to claim 2, characterized in that, The positioning structure includes an annular positioning groove (4b1) located inside the gripping part (4b) and a positioning protrusion (3a) located on the side of the lower core puller (3), with the positioning protrusion (3a) embedded in the annular positioning groove (4b1).

4. The production mold for electrical insulation components according to claim 2, characterized in that, The positioning structure includes an annular positioning part located inside the gripping part (4b) and an annular groove (4a2) located on the side of the lower core puller (3), with the annular positioning part embedded in the annular groove (4a2).

5. The production mold for electrical insulation components according to claim 1 or 2, characterized in that, The molded part (4) is made of high-temperature resistant silicone rubber.

6. The production mold for electrical insulation components according to claim 5, characterized in that, The forming part (4a) includes a plurality of annular protrusions (4a1) arranged axially along the lower core pull (3), and an annular groove (4a2) is formed between two adjacent annular protrusions (4a1). The bottom wall of the annular groove (4a2) is a circular arc surface.

7. The production mold for electrical insulation components according to claim 5, characterized in that, The molded part (4) is a cylindrical shape with the upper end closed.

8. The production mold for electrical insulation components according to claim 5, characterized in that, The molded part (4) is a circular sleeve with openings at both ends.

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