A thin-wall shell forming mold

Abstract

The present application relates to a thin-walled shell forming mold, which belongs to the field of processing and forming technology. The thin-walled shell forming mold includes a first mold body and a second mold body; the first mold body includes a first molding surface; the second mold body includes a second molding surface, and the second molding surface and the first molding surface form a molding cavity for molding the shell; wherein the first molding surface is provided with a gate for injecting molding liquid into the molding cavity, the second molding surface is provided with a plurality of first air holes for discharging gas from the molding cavity, and the second mold body is provided with an air cavity for accommodating gas, and the plurality of first air holes are connected to the air cavity. The thin-walled shell forming mold provided by the embodiment of the present application can improve the yield rate of the manufactured thin-walled shell.

Description

Technical Field

[0001] The present application relates to the field of processing and forming technology, and in particular to a thin-wall shell forming die. Background Art

[0002] Injection molding is an efficient plastic processing technology that injects molten plastic into the mold cavity and forms a product of the desired shape after cooling and solidification. The injection molding process mainly includes filling, holding pressure, cooling and demolding. The filling stage refers to the process in which the molten plastic is injected into the mold cavity through the nozzle under the high pressure of the injection molding machine. The holding pressure stage is to continue to apply pressure after the filling is completed to compensate for the shrinkage of the plastic and ensure the dimensional stability of the product. The cooling stage is the process of cooling and solidifying the plastic in the mold, and the demolding stage is to remove the cooled and solidified product from the mold.

[0003] When producing thin-walled shells in order to reduce the size of thin-walled devices such as ultra-thin displays, thin-walled molded parts are filled quickly during the injection molding process. The melt enters the cavity and displaces the air in the cavity. If these gases cannot be discharged in time, high pressure will be formed in the cavity, making it difficult to fill the melt and affecting the molding quality. In order to discharge the gas in the cavity in time, more exhaust ports need to be opened in the cavity. A large number of exhaust ports will affect the pressure stability in the pressure holding stage.

[0004] During the holding stage, the size of the holding pressure has a direct impact on the density, shrinkage rate and dimensional stability of the plastic part. If the holding pressure is greater than the external pressure of the mold, the molding liquid may enter the exhaust port, resulting in bulges on the surface of the thin-walled shell and depressions or cavities in the part of the thin-walled shell located around the exhaust port. In addition, since there are many exhaust ports in the mold, the amount of molding liquid entering the exhaust port also increases, which makes the pressure in the cavity decrease at a faster rate, resulting in the continuous insufficient holding pressure inside the molding cavity or frequent switching between the insufficient state and the normal state, so that the local area of ​​the thin-walled shell may have internal defects such as holes and looseness caused by insufficient holding pressure, resulting in a low yield rate of the manufactured thin-walled shell. Summary of the invention

[0005] The purpose of the present application is to provide a thin-walled shell forming die to address the above-mentioned problems, which can improve the yield rate of the manufactured thin-walled shell and improve the above-mentioned problems.

[0006] This application is achieved through the following technical solutions:

[0007] In some embodiments, the present application provides a thin-walled shell molding mold, which includes a first mold body and a second mold body; the first mold body includes a first molding surface; the second mold body includes a second molding surface, and the second molding surface and the first molding surface form a molding cavity for molding the shell; wherein the first molding surface is provided with a gate for injecting molding liquid into the molding cavity, the second molding surface is provided with a plurality of first air holes for discharging gas from the molding cavity, and an air cavity for accommodating gas is provided inside the second mold body, and the plurality of first air holes connect the air cavity.

[0008] In the technical solution of the embodiment of the present application, the first molding surface is provided with a gate for injecting molding liquid into the molding cavity, and the second molding surface is provided with a plurality of first air holes for discharging gas from the molding cavity. During the injection molding process for producing a thin-walled shell, the injection molding machine injects molding liquid into the molding cavity, and an air cavity for accommodating gas is provided inside the second mold body. The plurality of first air holes connect the air cavities, and the molding liquid pushes the air in the molding cavity into the first air holes, and the air in the first air holes enters the air cavity again, and the internal air pressure of the air cavity rises accordingly. After the injection molding is completed, it enters the pressure holding stage, and the injection molding machine continues to inject molding liquid into the molding cavity. The molding liquid newly injected into the molding cavity can fill the original molding liquid in the molding cavity. The size shrinks and the size vacated during the cooling process, so that the molding liquid can also fill the molding cavity during the gradual cooling process, and pressure is continuously applied to the molding liquid in the molding cavity. The air cavity and the first air holes are pressed together. The higher pressure in the first pore can work together with the internal viscous resistance of the viscous molding liquid to prevent the molding liquid from entering the first pore, thereby reducing the probability of a sudden decrease in the internal pressure of the molding cavity caused by the molding liquid entering the first pores which are provided with a large number of first pores for making a thin-walled shell, so that the holding pressure inside the molding cavity can be maintained in a relatively stable numerical range, reducing the probability of internal defects such as holes and looseness caused by insufficient holding pressure in local areas of the thin-walled shell, thereby improving the dimensional stability and surface quality of the thin-walled shell; in addition, preventing the molding liquid from entering the first pore can also avoid the probability of defects such as depressions or cavities in the part of the thin-walled shell located around the first pore, and avoid causing protrusions on the surface of the thin-walled shell, thereby eliminating the subsequent processing steps of removing the protrusions on the surface of the thin-walled shell, and reducing the difficulty of subsequent processing of the thin-walled shell.

[0009] In some embodiments, the aperture of the first pore is d, satisfying 6mm≤d≤10mm.

[0010] In the technical solution of the embodiment of the present application, when the aperture d of the first pore satisfies 6mm≤d≤10mm, the gas in the molding cavity can be smoothly pushed into the first pore and the air cavity during the injection of the molding liquid, and after the molding liquid is filled, the capillary phenomenon, the viscous resistance of the molding liquid and the internal pressure of the air cavity can work together to prevent the molding liquid from entering the first pore, thereby ensuring the dimensional stability and surface quality of the thin-walled shell and improving the yield rate of the produced thin-walled shell.

[0011] In some embodiments, a first piston is disposed inside the air cavity, and the first piston slides with the inner wall of the air cavity. The first piston divides the air cavity into an air storage area and a pressure regulating area. A plurality of first air holes are connected to the air storage area. The first piston moves along a first direction to adjust the size of the air storage area and the pressure regulating area. The first direction is the closing direction of the first mold body and the second mold body.

[0012] In the technical solution of the embodiment of the present application, a first piston is arranged inside the air cavity, and the first piston slides with the inner wall of the air cavity. The first piston divides the air cavity into an air storage area and a pressure regulating area. A plurality of first air holes are connected to the air storage area. When the internal air pressure of the air storage area rises to a level close to the holding pressure in the molding cavity, the piston rises under the push of the internal air pressure of the air storage area, thereby increasing the size of the air storage area and reducing the internal pressure of the air storage area, thereby reducing the risk of the internal pressure of the air storage area being greater than the holding pressure, and reducing the risk of defects such as air holes appearing on the surface of the thin-walled shell due to the air pressure in the air storage area being pressed into the molding cavity.

[0013] In some embodiments, a first convex ring is further provided on the inner wall of the air cavity, and the first convex ring is located on the side of the first piston facing the air storage area, and the inner diameter of the first convex ring is smaller than the outer diameter of the first piston.

[0014] In the technical solution of the embodiment of the present application, a first convex ring is further provided on the inner wall of the air cavity, and the first convex ring is located on the side of the first piston facing the air storage area. When the supporting force applied by the internal pressure of the air storage area on the first piston is less than the gravity of the first piston, the first piston will descend until it is supported by the first convex ring to be suspended in the air cavity, thereby preventing the first piston from falling and blocking the first air hole, allowing the air in the molding cavity to easily pass through the first air hole, thereby reducing the risk that the air in the molding cavity cannot be removed in time.

[0015] In some embodiments, a first step surface facing the first piston is formed between the first convex ring and the inner wall of the air cavity, and the first step surface is provided with an elastic gasket.

[0016] In the technical solution of the embodiment of the present application, the rapid cooling of the mold and the fast cooling and shrinkage rate of the molding liquid in the molding cavity will cause the internal air pressure of the air storage area to drop relatively quickly. The rapid drop in the air pressure in the air storage area causes the supporting force of the first piston from the air in the air storage area to decrease relatively quickly, and the combined force of the gravity on the first piston and the supporting force from the air in the air storage area toward the air storage area increases relatively quickly, causing the first piston to accelerate toward the air storage area. The first step surface is provided with an elastic gasket, which can absorb the kinetic potential energy of the first piston moving relatively quickly and buffer a part of the impact force generated by the collision between the first piston and the first convex ring, thereby reducing the risk of damage to the first piston and extending the service life of the first piston.

[0017] In some embodiments, a partition and a second piston are also provided in the pressure regulating zone. The second piston is located on the side of the partition away from the first piston. The partition and the second piston divide the pressure regulating zone into a first chamber, a second chamber and a third chamber. The first chamber is located between the partition and the first piston, and the second chamber is located between the partition and the second piston. The first chamber, the second chamber and the third chamber are arranged in sequence along the first direction; the partition is fixedly connected to the inner wall of the air cavity, the second piston is slidably matched with the inner wall of the air cavity, the first piston and the second piston are connected by a connecting rod, and the connecting rod passes through the partition and is sealed with the partition.

[0018] In the technical solution of the embodiment of the present application, a partition and a second piston are also provided in the pressure regulating area, the partition is fixedly connected to the inner wall of the air cavity, the second piston is slidably matched with the inner wall of the air cavity, the first piston and the second piston are connected by a connecting rod, the first piston and the second piston can move synchronously driven by the connecting rod, the inner wall of the air cavity can limit the moving direction of the first piston and the second piston, the first piston and the second piston can also move synchronously and limit each other under the drive of the connecting rod, thereby reducing the risk of the first piston and / or the second piston flipping or moving away from the first direction, the connecting rod passes through the partition and is sealed with the partition, the partition and the partition are arranged in cooperation with each other to limit the moving direction of the connecting rod, thereby reducing the risk of the connecting rod deviating from the first direction.

[0019] In some embodiments, the second chamber and the third chamber are completely filled with a damping medium having fluidity, and the second piston is provided with a first through hole for the damping medium to pass through.

[0020] In the technical solution of the embodiment of the present application, in the process of the second piston moving along the first direction driven by the first piston, as the second piston moves, the size of the second chamber and the size of the third chamber are respectively reduced or increased, so that the damping medium in the second chamber and the third chamber flows between the second chamber and the second chamber through the first through hole, and the direction in which the damping medium flows through the first through hole is opposite to the moving direction of the second piston. The damping medium flows through the second piston to generate a damping force in the same direction as the damping medium. This damping force is proportional to the movement speed of the second piston, that is, the greater the speed, the greater the damping force. The damping force can act on the first piston through the connecting rod, reducing the force applied to the first piston when it moves, so that the first piston moves at a slower speed, and the size of the gas storage area is reduced or increased at a slower speed, reducing the risk of the first pore generating a sudden suction or thrust on the molding liquid in the molding cavity due to a sudden decrease or increase in the internal air pressure of the gas storage area, thereby reducing the risk of surface defects caused by the thin-walled shell being affected by this sudden suction or thrust, improving the surface quality of the thin-walled shell, and improving the yield rate of the produced thin-walled shell.

[0021] In some embodiments, there are multiple first through holes, a connecting rod is connected to the center of the second piston, and multiple first through holes are arranged around the connecting rod.

[0022] In the technical solution of the embodiment of the present application, there are multiple first through holes, so that the damping medium in the second chamber and the third chamber can flow between the second chamber and the third chamber through the multiple first through holes, avoiding the concentration of the damping medium at a single first through hole causing excessive pressure on the local part of the second piston. The connecting rod is connected to the center of the second piston, and the multiple first through holes are arranged around the connecting rod, so that the damping force at various parts of the second piston is similar, thereby reducing the risk of the second piston flipping or local force deformation.

[0023] In some embodiments, the inner wall of the first chamber is provided with a second air hole and a second convex ring, the second air hole is provided between the second convex ring and the partition, and the inner diameter of the second convex ring is smaller than the outer diameter of the first piston.

[0024] In the technical solution of the embodiment of the present application, the inner wall of the first chamber is provided with a second air hole and a second convex ring. When the size of the first chamber increases with the movement of the first piston, the first chamber can inhale air through the second air hole to keep the internal pressure of the first chamber unchanged. When the size of the first chamber decreases with the movement of the first piston, the first chamber can discharge air through the second air hole to keep the internal pressure of the first chamber unchanged. The second air hole allows the internal pressure of the first chamber to be equal to the atmospheric pressure and remain unchanged, so that the downward pressure on the first piston is mainly the gravity of itself and the second piston, making the force on the first piston clearer and more obvious. The inner diameter of the second convex ring is smaller than the outer diameter of the first piston. The second convex ring limits the moving range of the first piston in the air cavity to avoid the first piston blocking the second air hole or the air storage area is connected to the second air hole, resulting in the complete failure of the air cavity to adjust the internal pressure of the first air hole.

[0025] In some embodiments, a second step surface facing the first piston is formed between the second convex ring and the inner wall of the first chamber, and the second step surface is provided with an elastic gasket.

[0026] In the technical solution of the embodiment of the present application, the air in the molding cavity is quickly pushed into the air storage area, which will cause the internal air pressure of the air storage area to rise relatively quickly. The rapid rise in the air pressure in the air storage area causes the supporting force of the first piston from the air in the air storage area to increase relatively quickly. The combined force of the gravity on the first piston and the supporting force from the air in the air storage area toward the pressure regulating area increases relatively quickly, causing the first piston to accelerate toward the second convex ring. The second step surface is provided with an elastic gasket, which can absorb the kinetic potential energy of the first piston moving relatively quickly and buffer a part of the impact force generated by the collision between the first piston and the second convex ring, thereby reducing the risk of damage to the first piston and extending the service life of the first piston.

[0027] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the external structure of a thin-walled shell forming mold provided in some embodiments of the present application;

[0030] Figure 2A top view of a thin-walled shell forming mold provided for some embodiments of the present application;

[0031] Figure 3 for Figure 2 Sectional view at AA in the middle;

[0032] Figure 4 A side view of a thin-walled shell forming die provided for some embodiments of the present application;

[0033] Figure 5 for Figure 4 Sectional view at the middle BB;

[0034] Figure 6 for Figure 5 A magnified view of the structure in the middle.

[0035] Icons: 1-first mold body; 10-first molding surface; 2-second mold body; 20-second molding surface; 200-first air hole; 21-air cavity; 210-first piston; 211-gas storage area; 212-pressure regulating area; 2120-first chamber; 2121-second chamber; 2122-third chamber; 213-first convex ring; 2130-first step surface; 214-partitioning piece; 215-second piston; 2150-first through hole; 216-connecting rod; 217-second air hole; 218-second convex ring; 2180-second step surface; 3-molding cavity; X-first direction. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0038] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0041] The term "multiple" as used in the present application refers to more than two (including two). Similarly, the term "multiple groups" refers to more than two groups (including two groups), and the term "multiple sheets" refers to more than two sheets (including two sheets).

[0042] According to some embodiments of the present application, optionally, Figure 1~Figure 5 As shown, the present application provides a thin-walled shell molding mold, which includes a first mold body 1 and a second mold body 2; the first mold body 1 includes a first molding surface 10; the second mold body 2 includes a second molding surface 20, and the second molding surface 20 and the first molding surface 10 form a molding cavity 3 for molding the shell; wherein the first molding surface 10 is provided with a gate for injecting molding liquid into the molding cavity 3, the second molding surface 20 is provided with a plurality of first air holes 200 for discharging gas from the molding cavity 3, and the second mold body 2 is provided with an air cavity 21 for accommodating gas, and the plurality of first air holes 200 are connected to the air cavity 21.

[0043] The first mold body 1 can be set on the ground or a work platform. When the molding liquid is injected into the molding cavity 3 through the gate of the first molding surface 10, the molding liquid fills the molding cavity 3 from bottom to top, so that the molding liquid finally flows to the first air hole 200 of the second molding surface 20, so that the gas in the molding cavity 3 can be smoothly pushed out by the molding liquid.

[0044] The first mold body 1 may be a fixed mold, and the second mold body 2 may be a movable mold.

[0045] Before injecting the molding liquid into the molding cavity 3, an inert gas can be first injected into the molding cavity 3, the first air hole 200 and the air cavity 21 to prevent the liquid droplets, oxygen and other components contained in the original air in the molding cavity 3 and the air cavity 21 from being oxidized or burned under the influence of the high temperature during the injection molding process, resulting in an oxide layer or burn marks on the surface of the thin-walled shell, affecting the outer surface quality of the thin-walled shell.

[0046] The product mentioned in this application is a thin-walled shell; the molding liquid mentioned in this application is molten plastic.

[0047] The first molding surface 10 is provided with a gate for injecting molding liquid into the molding cavity 3, and the second molding surface 20 is provided with a plurality of first air holes 200 for discharging gas from the molding cavity 3. During the injection molding process of producing the thin-walled shell, the injection molding machine injects molding liquid into the molding cavity 3, and an air cavity 21 for accommodating gas is provided inside the second mold body 2. The plurality of first air holes 200 are connected to the air cavity 21, and the molding liquid pushes the air in the molding cavity 3 into the first air holes 200, and the air in the first air holes 200 enters the air cavity 21 again, and the internal air pressure of the air cavity 21 rises accordingly. After the injection molding is completed, it enters the pressure holding stage, and the injection molding machine continues to inject molding liquid into the molding cavity 3. The molding liquid newly injected into the molding cavity 3 can fill the original molding liquid in the molding cavity 3. The size shrinks and the size is vacated during the cooling process, so that the molding liquid can also fill the molding cavity 3 during the gradual cooling process, and continuously applies pressure to the molding liquid in the molding cavity 3. 21 and the higher pressure in the first pore 200 can work together with the internal management of the viscous molding liquid to prevent the molding liquid from entering the first pore 200, thereby reducing the probability of a sudden decrease in the internal pressure of the molding cavity 3 caused by the molding liquid entering the first pore 200 which is provided with a large number of first pores 200 for making a thin-walled shell, so that the holding pressure inside the molding cavity 3 can be maintained in a relatively stable numerical range, reducing the probability of internal defects such as holes and looseness caused by insufficient holding pressure in local areas of the thin-walled shell, thereby improving the dimensional stability and surface quality of the thin-walled shell; in addition, preventing the molding liquid from entering the first pore 200 can also avoid the probability of defects such as depressions or cavities in the part of the thin-walled shell located around the first pore 200, and avoid causing protrusions on the surface of the thin-walled shell, thereby eliminating the subsequent processing steps of removing the protrusions on the surface of the thin-walled shell, and reducing the difficulty of subsequent processing of the thin-walled shell.

[0048] According to some embodiments of the present application, optionally, Figure 3 , Figure 5~Figure 6 As shown, the aperture of the first air hole 200 is d, which satisfies 6mm≤d≤10mm.

[0049] When d is less than 6 mm, the aperture of the first pore 200 is too small, resulting in that during the process of the molding liquid filling the molding cavity 3, the gas in the molding cavity 3 leaves the molding cavity 3 through the first pore 200 at a slow speed, and the exhaust is insufficient. The gas generated by the decomposition of the air and the molding liquid in the molding cavity 3 cannot be discharged in time, which will lead to defects such as difficulty in filling the molding liquid, insufficient filling, pores, and weld marks. In severe cases, it may also cause damage to the mold or burning of the plastic.

[0050] When d>10mm, the aperture of the first pore 200 is too large, and the capillary phenomenon and the viscous resistance of the molding liquid itself have a weak restricting effect on the flow of the molding liquid around the first pore 200. It is difficult to prevent the molding liquid from flowing into the first pore 200 only by the internal pressure of the air cavity 21.

[0051] When the aperture d of the first air hole 200 satisfies 6mm≤d≤10mm, the gas in the molding cavity 3 can be smoothly pushed into the first air hole 200 and the air cavity 21 during the injection of the molding liquid, and after the molding liquid is filled, the capillary phenomenon, the viscous resistance of the molding liquid and the internal pressure of the air cavity 21 can work together to prevent the molding liquid from entering the first air hole 200, thereby ensuring the dimensional stability and surface quality of the thin-walled shell and improving the yield rate of the produced thin-walled shell.

[0052] According to some embodiments of the present application, optionally, Figure 3 , Figure 5~Figure 6 As shown, a first piston 210 is provided inside the air cavity 21. The first piston 210 slides with the inner wall of the air cavity 21. The first piston 210 divides the air cavity 21 into an air storage area 211 and a pressure regulating area 212. A plurality of first air holes 200 are connected to the air storage area 211. The first piston 210 moves along a first direction X to adjust the size of the air storage area 211 and the pressure regulating area 212. The first direction X is the closing direction of the first mold body 1 and the second mold body 2.

[0053] The X direction shown in the figure is the first direction X.

[0054] The gravity on the first piston 210 is slightly smaller than the holding pressure in the molding cavity 3, and the first piston 210 can rise under the push of the air pressure in the pressure regulating area 212, and then fall under the action of its own gravity;

[0055] When the first piston 210 rises, the size of the gas storage area 211 increases while the size of the pressure regulating area 212 decreases;

[0056] When the first piston 210 descends, the size of the gas storage area 211 decreases and the size of the pressure regulating area 212 increases.

[0057] A first piston 210 is provided inside the air cavity 21. The first piston 210 slides with the inner wall of the air cavity 21. The first piston 210 divides the air cavity 21 into an air storage area 211 and a pressure regulating area 212. A plurality of first air holes 200 are connected to the air storage area 211. When the internal air pressure of the air storage area 211 rises to a level close to the holding pressure in the molding cavity 3, the piston rises under the push of the internal air pressure of the air storage area 211, thereby increasing the size of the air storage area 211 and reducing the internal pressure of the air storage area 211, thereby reducing the risk that the internal pressure of the air storage area 211 is greater than the holding pressure, and reducing the risk that air is pressed into the molding cavity 3 under the action of the air pressure in the air storage area 211, resulting in defects such as air holes on the surface of the thin-walled shell.

[0058] According to some embodiments of the present application, optionally, Figure 5~Figure 6 As shown, the inner wall of the air cavity 21 is further provided with a first convex ring 213 , which is located on the side of the first piston 210 facing the air storage area 211 , and the inner diameter of the first convex ring 213 is smaller than the outer diameter of the first piston 210 .

[0059] The first convex ring 213 can be composed of a plurality of protrusions protruding from the inner wall of the air cavity 21, so that when the first piston 210 is supported by the first convex ring 213, the contact area between the air in the air storage area 211 and the first piston 210 is larger (compared with the first convex ring 213 being a complete annular structure), making it easier for the first piston 210 to be pushed by air pressure from a static state to an active state.

[0060] The inner wall of the air cavity 21 is also provided with a first convex ring 213, which is located on the side of the first piston 210 facing the air storage area 211. When the supporting force exerted by the internal pressure of the air storage area 211 on the first piston 210 is less than the gravity of the first piston 210, the first piston 210 will drop until it is supported by the first convex ring 213 to be suspended in the air cavity 21, thereby preventing the first piston 210 from falling and blocking the first air hole 200, allowing the air in the molding cavity 3 to easily pass through the first air hole 200, thereby reducing the risk that the air in the molding cavity 3 cannot be removed in time.

[0061] According to some embodiments of the present application, optionally, Figure 6 As shown, a first step surface 2130 facing the first piston 210 is formed between the first convex ring 213 and the inner wall of the air cavity 21 , and the first step surface 2130 is provided with an elastic gasket.

[0062] The padding material may be, but is not limited to, silicone rubber, EPDM rubber elastic pad, thermoplastic insulation cushion, urethane foam plastic, etc.

[0063] The first piston 210 may be sealedly connected to the inner wall of the air chamber 21 .

[0064] The rapid cooling of the mold and the fast cooling and shrinkage rate of the molding liquid in the molding cavity 3 will cause the internal air pressure of the air storage area 211 to drop relatively quickly. The rapid drop in the air pressure in the air storage area 211 causes the supporting force of the first piston 210 from the air in the air storage area 211 to decrease relatively quickly. The combined force of the gravity on the first piston 210 and the supporting force from the air in the air storage area 211 toward the air storage area 211 increases relatively quickly, causing the first piston 210 to accelerate toward the first convex ring 213. The first step surface 2130 is provided with an elastic gasket, which can absorb the kinetic potential energy of the first piston 210 moving relatively quickly and buffer a part of the impact force generated by the collision between the first piston 210 and the first convex ring 213, thereby reducing the risk of damage to the first piston 210 and extending the service life of the first piston 210.

[0065] According to some embodiments of the present application, optionally, Figure 5~Figure 6 As shown, a separator 214 and a second piston 215 are also provided in the pressure regulating area 212. The second piston 215 is located on the side of the separator 214 away from the first piston 210. The separator 214 and the second piston 215 separate the pressure regulating area 212 into a first chamber 2120, a second chamber 2121 and a third chamber 2122. The first chamber 2120 is located between the separator 214 and the first piston 210, and the second chamber 2121 is located between the separator 214 and the second piston 215. The first chamber 2120, the second chamber 2121 and the third chamber 2122 are arranged in sequence along the first direction X; the separator 214 is fixedly connected to the inner wall of the air cavity 21, and the second piston 215 is slidably matched with the inner wall of the air cavity 21. The first piston 210 and the second piston 215 are connected by a connecting rod 216, and the connecting rod 216 passes through the separator 214 and is sealed with the separator 214.

[0066] The second piston 215 may be sealedly connected to the inner wall of the air chamber 21 .

[0067] The total weight of the first piston 210 and the second piston 215 is less than and close to the holding pressure in the molding cavity 3 .

[0068] The partition 214 is provided with a through hole for the connecting rod 216 to pass through, and the axial direction of the through hole is parallel to the first direction X. The through hole is sealedly connected to the connecting rod 216 .

[0069] A separator 214 and a second piston 215 are also provided in the pressure regulating area 212. The separator 214 is fixedly connected to the inner wall of the air cavity 21, and the second piston 215 is slidably matched with the inner wall of the air cavity 21. The first piston 210 and the second piston 215 are connected by a connecting rod 216. The first piston 210 and the second piston 215 can move synchronously under the drive of the connecting rod 216. The inner wall of the air cavity 21 can limit the moving direction of the first piston 210 and the second piston 215. The first piston 210 and the second piston 215 can also move synchronously and limit each other under the drive of the connecting rod 216, thereby reducing the risk of the first piston 210 and / or the second piston 215 flipping or moving away from the first direction X. The connecting rod 216 passes through the separator 214 and is sealed with the separator 214. The separator 214 cooperates with the separator 214 to set and limit the moving direction of the connecting rod 216, thereby reducing the risk of the connecting rod 216 deviating from the first direction X.

[0070] According to some embodiments of the present application, optionally, Figure 5~Figure 6 As shown, the second chamber 2121 and the third chamber 2122 are completely filled with the damping medium having fluidity, and the second piston 215 is provided with a first through hole 2150 for the damping medium to pass through.

[0071] The damping medium mentioned in the present application may be, but is not limited to, damping oil, elastic cement, silicone-based glue, silicone oil, etc.

[0072] In the process that the second piston 215 moves along the first direction X driven by the first piston 210, as the second piston 215 moves, the size of the second chamber 2121 and the size of the third chamber 2122 are respectively reduced or increased, so that the damping medium in the second chamber 2121 and the third chamber 2122 flows between the second chamber 2121 and the second chamber 2121 through the first through hole 2150. The direction in which the damping medium flows through the first through hole 2150 is opposite to the moving direction of the second piston 215. The damping medium flows through the second piston 215 to generate a damping force in the same direction as the damping medium. This damping force is inversely proportional to the movement of the second piston 215. The damping force can act on the first piston 210 through the connecting rod 216, thereby reducing the force applied to the first piston 210 when the first piston 210 moves, causing the first piston 210 to move more slowly, and causing the size of the gas storage area 211 to decrease or increase more slowly, thereby reducing the risk of the first air hole 200 generating a sudden suction or thrust on the molding liquid in the molding cavity 3 due to a sudden decrease or increase in the internal air pressure of the gas storage area 211, thereby reducing the risk of surface defects of the thin-walled shell caused by the sudden suction or thrust, thereby improving the surface quality of the thin-walled shell and improving the yield rate of the produced thin-walled shell.

[0073] According to some embodiments of the present application, optionally, Figure 5~Figure 6As shown, there are multiple first through holes 2150 , the connecting rod 216 is connected to the center of the second piston 215 , and multiple first through holes 2150 are arranged around the connecting rod 216 .

[0074] When the second piston 215 is a circular piston, the position where the connecting rod 216 connects to the second piston 215 is the axis of the second piston 215 .

[0075] There are multiple first through holes 2150, so that the damping medium in the second chamber 2121 and the third chamber 2122 can flow between the second chamber 2121 and the third chamber 2122 through the multiple first through holes 2150, avoiding the concentration of the damping medium in a single first through hole 2150, which may cause excessive pressure on the local part of the second piston 215. The connecting rod 216 is connected to the center of the second piston 215, and the multiple first through holes 2150 are arranged around the connecting rod 216, so that the damping force at various parts of the second piston 215 is similar, thereby reducing the risk of the second piston 215 flipping over or local deformation due to force.

[0076] According to some embodiments of the present application, optionally, Figure 5~Figure 6 As shown, the inner wall of the first chamber 2120 is provided with a second air hole 217 and a second convex ring 218 . The second air hole 217 is provided between the second convex ring 218 and the partition 214 . The inner diameter of the second convex ring 218 is smaller than the outer diameter of the first piston 210 .

[0077] The second air hole 217 connects the first chamber 2120 with the outside.

[0078] The inner wall of the first chamber 2120 is provided with a second air hole 217 and a second convex ring 218. When the size of the first chamber 2120 increases with the movement of the first piston 210, the first chamber 2120 can inhale air through the second air hole 217 to keep the internal pressure of the first chamber 2120 unchanged. When the size of the first chamber 2120 decreases with the movement of the first piston 210, the first chamber 2120 can discharge air through the second air hole 217 to keep the internal pressure of the first chamber 2120 unchanged. The second air hole 217 allows the internal pressure of the first chamber 2120 to be equal to Atmospheric pressure remains unchanged, so that the downward pressure on the first piston 210 is mainly the gravity of itself and the second piston 215, making the force on the first piston 210 clearer and more obvious. The inner diameter of the second convex ring 218 is smaller than the outer diameter of the first piston 210. The second convex ring 218 limits the movement range of the first piston 210 in the air cavity 21 to prevent the first piston 210 from blocking the second air hole 217 or the air storage area 211 from being connected to the second air hole 217, resulting in the complete failure of the air cavity 21 to adjust the internal pressure of the first air hole 200.

[0079] According to some embodiments of the present application, optionally, Figure 6As shown, a second step surface 2180 facing the first piston 210 is formed between the second convex ring 218 and the inner wall of the first chamber 2120 , and the second step surface 2180 is provided with an elastic gasket.

[0080] The padding material may be, but is not limited to, silicone rubber, EPDM rubber elastic pad, thermoplastic insulation cushion, urethane foam plastic, etc.

[0081] The air in the molding cavity 3 is quickly pushed into the air storage area 211, which will cause the internal air pressure of the air storage area 211 to rise relatively quickly. The rapid rise in the air pressure in the air storage area 211 causes the supporting force of the first piston 210 from the air in the air storage area 211 to increase relatively quickly. The combined force of the gravity on the first piston 210 and the supporting force from the air in the air storage area 211 toward the pressure regulating area 212 increases relatively quickly, causing the first piston 210 to accelerate toward the second convex ring 218. The second step surface 2180 is provided with an elastic gasket, which can absorb the kinetic potential energy of the first piston 210 moving relatively quickly, and buffer a part of the impact force generated by the collision between the first piston 210 and the second convex ring 218, thereby reducing the risk of damage to the first piston 210 and extending the service life of the first piston 210.

[0082] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A thin-wall shell forming mold, characterized in that: include: A first mold body including a first molding surface; A second mold body, comprising a second molding surface, wherein the second molding surface and the first molding surface enclose a molding cavity for molding the shell; The first molding surface is provided with a gate for injecting molding liquid into the molding cavity, the second molding surface is provided with a plurality of first air holes for discharging gas from the molding cavity, an air cavity for accommodating gas is provided inside the second mold body, and the plurality of first air holes are connected to the air cavity; A first piston is arranged inside the air cavity, the first piston is slidably matched with the inner wall of the air cavity, the first piston divides the air cavity into an air storage area and a pressure regulating area, a plurality of the first air holes are connected with the air storage area, the first piston moves along a first direction to adjust the size of the air storage area and the pressure regulating area, and the first direction is the mold closing direction of the first mold body and the second mold body; A separator and a second piston are also provided in the pressure regulating area, the second piston is located on a side of the separator away from the first piston, the separator and the second piston divide the pressure regulating area into a first chamber, a second chamber and a third chamber, the first chamber is located between the separator and the first piston, the second chamber is located between the separator and the second piston, and the first chamber, the second chamber and the third chamber are arranged in sequence along the first direction; The partition is fixedly connected to the inner wall of the air cavity, the second piston is slidably matched with the inner wall of the air cavity, the first piston and the second piston are connected by a connecting rod, and the connecting rod passes through the partition and is sealed with the partition; The second chamber and the third chamber are completely filled with a damping medium having fluidity, and the second piston is provided with a first through hole for the damping medium to pass through.

2. A thin-wall shell forming mold according to claim 1, characterized in that: The aperture of the first pore is d, which satisfies 6mm≤d≤10mm.

3. A thin-wall shell forming mold according to claim 1, characterized in that: A first convex ring is further provided on the inner wall of the air cavity. The first convex ring is located on the side of the first piston facing the air storage area. The inner diameter of the first convex ring is smaller than the outer diameter of the first piston.

4. A thin-wall shell forming mold according to claim 3, characterized in that: A first step surface facing the first piston is formed between the first convex ring and the inner wall of the air cavity, and the first step surface is provided with an elastic gasket.

5. A thin-wall shell forming mold according to claim 1, characterized in that: There are multiple first through holes, the connecting rod is connected to the center of the second piston, and multiple first through holes are arranged around the connecting rod.

6. A thin-wall shell forming mold according to claim 1, characterized in that: The inner wall of the first chamber is provided with a second air hole and a second convex ring, the second air hole is provided between the second convex ring and the partition, and the inner diameter of the second convex ring is smaller than the outer diameter of the first piston.

7. A thin-wall shell forming mold according to claim 6, characterized in that: A second step surface facing the first piston is formed between the second convex ring and the inner wall of the first chamber, and the second step surface is provided with an elastic gasket.

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