Rubber vulcanization mold convenient to demold and demolding method

Abstract

The invention relates to a rubber vulcanization mold convenient to demold and a demolding method. The vulcanization mold comprises a lower mold, a middle mold I and a middle mold II, wherein the middle mold I and the middle mold II are sequentially stacked on the lower mold; the first middle die is connected with the lower die through a fixing screw, and the second middle die is in limiting fit with the first middle die through a positioning pin. The movable die is formed by connecting an upper die, a die core and a positioning pin in an interference fit manner; wherein the upper die is provided with a counterbore and a through hole, the top of the die core is pressed into the counterbore in an interference fit mode, and the upper end of the positioning pin is pressed into the through hole in an interference fit mode. The frequency of direct contact between a worker and the mold is greatly reduced, and the safety risk is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of rubber vulcanization molds, and particularly relates to a rubber vulcanization mold facilitating demolding and a demolding method. BACKGROUND

[0002] In the composition, production process or other fields of transducers, a large number of deep-cavity rubber parts will be used, for example, some transducer packaging will use a preformed rubber sleeve, and a rubber sleeve with a very deep internal space will also be used for structural protection during production testing. Since the rubber vulcanization process is mature, batch production of rubber products by using the vulcanization process is one of the most preferred production methods.

[0003] Like the common vulcanization process, the vulcanization process of a deep-cavity rubber product also needs to go through fixed steps: raw material preparation, mold preheating, raw material loading, mold closing and vulcanization, demolding and trimming, and inspection. Considering the complexity of the mold and the shape characteristics of the rubber product, the convenience of product demolding directly affects the production efficiency of the entire product to a great extent. Generally, to facilitate product demolding, on the one hand, the mold cavity surface is polished to reduce friction from the perspective of mold design, and on the other hand, a release agent is sprayed before the raw material is loaded, and the principle is also to reduce the friction between the rubber and the mold. In addition, some special structural designs are also used for quick demolding, such as designing a spring-type or hydraulic-type demolding system, and setting a top plate structure in the mold to directly or indirectly act on the product and eject the product. For example, Chinese Patent Publication No. CN220030898U discloses a rubber part production mold with an air demolding system, which blows air to the product through an air inlet hole, an air duct and a blowing end to achieve demolding. Chinese Patent Publication No. CN214562541U discloses a vulcanization mold with an inflation channel and an inflation cavity designed in the lower mold of the mold, which assists demolding by injecting air. However, these prior art solutions still have obvious defects: during mold closing and vulcanization, the rubber material with high temperature and high pressure has good flowability and is easy to flow reversely into the air passage system along the air blowing port. This will cause two serious problems: first, the rubber material in the air passage accumulates and blocks the demolding air path; second, the rubber material in the air passage is connected with the product, which makes demolding more difficult.

[0004] In view of the deficiencies of the prior art, there is an urgent need to develop a rubber vulcanization mold that can effectively prevent the reverse flow of rubber material, reliable and efficient demolding, and safe operation. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a rubber vulcanization mold facilitating demolding and a demolding method to solve the technical problems of difficult demolding of deep-cavity rubber products, safety risks in the demolding process, and easy blockage of the air demolding scheme by rubber material in the prior art.

[0006] The technical solution of the present invention is to provide a rubber vulcanization mold that facilitates demolding, comprising:

[0007] The stationary mold includes a lower mold and two intermediate molds, one and two, stacked sequentially on the lower mold; the first intermediate mold is connected to the lower mold by fixing screws, and the second intermediate mold is limited to the first intermediate mold by a positioning pin;

[0008] The moving mold is composed of an upper mold, a mold core, and a locating pin connected by an interference fit; wherein, the upper mold is provided with a countersunk hole and a through hole, the top of the mold core is pressed into the countersunk hole by an interference fit, and the upper end of the locating pin is pressed into the through hole by an interference fit.

[0009] The first and second intermediate molds are provided with through holes. When the molds are closed, the core of the moving mold assembly passes downward through the through holes and together with the stationary molds to form a vulcanization cavity.

[0010] The mold core includes an outer shell, an inner shell, and a limiting nut;

[0011] The outer shell is a hollow columnar structure, with its outer surface being the inner surface of the cavity, a skirt at the top for interference fit with the upper mold, an internal threaded hole at the bottom opening, and an internal thread at the top opening.

[0012] The inner shell is a cylindrical body with an internal air passage. It has an external threaded part protruding downward at the bottom and a tool fitting hole at the top, which communicates with the upper end of the air passage. The inner shell is assembled in the inner cavity of the outer shell, and its external threaded part mates with the internal threaded hole at the bottom opening of the outer shell. The end of the air passage radially penetrates the shell of the inner shell.

[0013] The limiting nut is threaded to the internal thread of the opening at the top of the outer shell, and has a through hole in the center;

[0014] In the vulcanized state, the external threaded portion of the inner shell is screwed tightly into the internal threaded hole of the outer shell, and the bottom end of the inner shell seals the bottom end opening of the outer shell.

[0015] In the demolded state, the inner shell and outer shell are disconnected by passing the tool through the central through hole of the limiting nut. Then, compressed air is introduced through the through hole of the limiting nut. The compressed air overflows from the lower port of the air passage, lifts the inner shell, and sprays out from the bottom opening of the outer shell, acting on the inner surface of the rubber product to achieve demolding.

[0016] The mold core of this invention has a special internal structure. One end of the mold core has an air inlet that can be connected to an air source such as a compressed air gun on site. A solid baffle is installed inside to prevent the rubber material from flowing back into the air channel. When demolding, if the product is stuck to the mold core and difficult to remove, simply release the baffle inside the mold core and connect compressed air to the mold core. Through the internal air channel, the high-pressure, high-speed compressed air pushes up the internal baffle, i.e., the inner shell, and at the same time acts directly on the inner surface of the rubber product through the air outlet, separating the rubber from the mold core from the bottom up, thus achieving efficient demolding. Under suitable conditions, the outlet of the compressed air gun can be fully optimized to achieve the goal of demolding in one go. At the same time, this method can also reduce the frequency of contact between people and high-temperature molds to a certain extent, reducing the risk of injury.

[0017] Preferably, the length of the external thread at the bottom of the inner shell is equal to the depth of the internal thread hole at the bottom of the outer shell, and the bottom surface of the inner shell has a taper to form an inverted frustum structure.

[0018] Preferably, the outer surface of the housing has a demolding taper of 0.5° to 1°, the minor diameter of the internal thread opening at the top is greater than or equal to the inner diameter of the hollow part of the housing body, and the major diameter of the internal thread hole opening at the bottom is less than or equal to the inner diameter of the hollow part of the housing body.

[0019] Preferably, the overall thickness of the limiting nut is less than the depth of the internal thread at the top of the outer shell, and a slot is machined at the top.

[0020] Preferably, the middle mold has through holes that are clearance fit with the large ends of all the locating pins, and the upper mold has through holes that are interference fit with the small ends of the locating pins.

[0021] Preferably, the mold is configured as a multi-core structure, with multiple cores arranged at intervals on the upper mold in an interference fit manner, and the middle mold one and middle mold two are provided with corresponding multiple through holes.

[0022] Preferably, the tool fitting hole is a hexagonal countersunk hole for use with an internal hex wrench.

[0023] Preferably, the air passage in the inner shell is an inverted T-shaped air passage with a tapered lower end that penetrates the conical wall of the bottom end face of the inner shell. More reasonably, the lower end of the air passage has two opposing air passage openings that penetrate the conical surface of the bottom end of the inner shell in opposite directions, so that the inner shell can be better lifted when compressed gas overflows.

[0024] The present invention also provides a demolding method using the above-mentioned rubber vulcanization mold, comprising the following steps:

[0025] After vulcanization, the moving mold assembly is completely separated from the stationary mold assembly;

[0026] When the rubber product is adsorbed onto the mold core, pass the operating tool through the through hole of the limit nut; and disconnect the threaded connection between the inner shell and the bottom of the outer shell.

[0027] Connect the compressed air source to the through hole of the limit nut;

[0028] Compressed air is introduced, which lifts the inner shell and ejects it from the opening at the bottom of the outer shell, thus removing the rubber product.

[0029] Preferably, when disengaging the threaded connection, the inner shell is rotated so that the external threaded portion at its bottom end is completely separated from the internal threaded hole at the bottom end of the outer shell.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The present invention provides a rubber vulcanizing mold that facilitates demolding. Utilizing a specially constructed mold core, it makes full use of compressed air commonly found on the production site to achieve rapid demolding and improve production efficiency. The mold core structure designed in this invention allows for a multi-stage mold design, eliminating concerns about difficulties in demolding due to mold core arrangement. Compared to common manual demolding, the mold designed in this invention significantly reduces the frequency of direct contact between workers and the mold, lowering safety risks. Attached Figure Description

[0032] Figure 1 This is a cross-sectional view of the rubber vulcanizing mold for easy demolding according to the present invention.

[0033] Figure 2 This is a cross-sectional view of the mold core structure of the present invention.

[0034] Figure 3 This is a schematic diagram illustrating the demolding principle of the present invention.

[0035] Among them, 1. lower mold; 2. middle mold one; 3. middle mold two; 4. upper mold; 5. mold core; 51. outer shell; 52. inner shell; 53. limit nut; 6. positioning pin; 7. fixing screw. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0037] A rubber vulcanization mold that facilitates demolding, such as Figure 1 As shown, it mainly includes a lower mold 1, a first middle mold 2, a second middle mold 3, an upper mold 4, a mold core 5, a locating pin 6, and a fixing screw 7. Among them,

[0038] The lower mold 1 is located at the bottom of the mold, the middle mold 1 2 is located on the lower mold 1, and the two are connected and fixed by multiple fixing screws 7. The middle mold 2 3 is located on the upper side of the middle mold 1 2, and the two are limited by positioning pins 6. The above are the stationary molds of the mold.

[0039] Specifically, the lower mold 1 is provided with countersunk through holes evenly distributed around its circumference, which are matched with the threaded holes at the bottom of the middle mold 2. The upper surface of the lower mold 1 is polished and serves as the bottom surface of the mold cavity. The middle mold 2 is provided with multiple through holes with a slight taper (not greater than 0.5°, the same below), the inner diameter of which is equivalent to the outer diameter of the rubber product, serving as part of the side surface of the mold cavity. The inner surface of the through holes is polished. The upper and lower end faces of the middle mold 2 are provided with countersunk platforms of a certain depth as running grooves, which also facilitate the use of tools to lift the mold. The lower end face is evenly distributed with threaded blind holes that mate with the lower mold 1. Three through holes are evenly distributed around the entire circumference and are interference-fitted with the small end of the locating pin 6; the middle mold 2 3 is provided with multiple through holes with a slight taper (not greater than 0.5°), which are also polished and are part of the side of the mold cavity. The inner diameter of the through hole is equivalent to the outer diameter of the rubber product. The lower inner diameter of the through hole is consistent with the upper inner diameter of the middle mold 1 2, and the overall taper is also consistent with the middle mold 1 2. A certain depth countersunk platform is provided on the upper end face of the middle mold 2 3 as a running groove, which also facilitates the use of tools to lift the mold; six through holes are evenly distributed around the entire circumference and are clearance-fitted with the large end of all the locating pins 6.

[0040] The upper mold 4, mold core 5, and locating pin 6 are connected by an interference fit, and the three together constitute the moving mold. The lower end face of the upper mold 4 is polished to serve as the cavity end face, and through holes that are evenly distributed around the circumference and are interference fit with the locating pin 6 are also evenly distributed around the circumference. Countersunk holes that are interference fit with the mold core 5 and through holes that are interference fit with the small end of the locating pin 6 are also evenly distributed around the circumference. The depth of the countersunk holes ensures that the mold core 5 does not extend beyond the upper end face of the upper mold 4.

[0041] In this embodiment, the mold core 5 has a special internal structure, such as... Figure 2 As shown, the assembly consists of an outer shell 51, an inner shell 52, and a limiting nut 53. The outer shell 51 is a special cylindrical body with its outer surface being the inner surface of the cavity, polished, and exhibiting a slight taper. It has a skirt at the top for mating with the countersunk hole of the upper mold 4. The inner side is cylindrically hollowed out, with a threaded hole at the bottom opening. The thread specification satisfies that the major diameter of the thread is less than or equal to the inner diameter of the outer shell 51. The top opening has an internal thread of a certain depth, with the minor diameter of the thread greater than or equal to the inner diameter of the outer shell 51. The inner shell 52 is a cylindrical body with an inverted T-shaped air passage on its inner side. Its bottom end has a downward-protruding external threaded column, the length of which (including the relief groove) is equal to the depth of the threaded hole at the bottom of the outer shell 51. The top of the inner shell 52 has a tool fitting hole, a hexagonal countersunk hole, for mating with an internal hex wrench. During assembly, the inner shell 52 is placed inside the outer shell 51, with a suitable clearance fit between them, facilitating the vertical movement of the inner shell 52 relative to the outer shell 51. The overall thickness of the limit nut 53 is less than the thread depth at the top of the outer shell 51. Its outer side is threaded and can be matched with the thread at the top of the outer shell 51. A through hole is provided in the middle. The size of the through hole should meet the following requirements: allow the aforementioned internal hex wrench to pass through smoothly, and at the same time be able to connect to the air outlet of the air source. A slot is machined on the top of the limit nut 53 to facilitate its own assembly.

[0042] This invention features an air passage inside the mold core that connects to the mold cavity. During vulcanization, the air passage inside the mold core and the mold cavity are isolated from each other by a threaded connection to prevent the rubber material inside the cavity from flowing back into the air passage. When demolding is required, an Allen wrench is used to remove the threaded connection inside the mold core, and then compressed air is introduced from the end of the mold core to achieve demolding.

[0043] In one implementation, the inner shell side at the lower end of the air passage is tapered, and the air passage extends radially through this point. Additionally, the upper end of the air passage extends to and connects with a hexagonal countersunk hole. Thus, the overall air passage design is an inverted T-shaped air passage with two opposing air passage openings at the lower end. This allows the compressed gas to better push against the inner shell 52 when it overflows from the air passage openings, thanks to the narrow, tapered space between the inner wall of the outer shell 51 and the end face of the inner shell 52.

[0044] Before product vulcanization, the mold core 5 is assembled in place. That is, first tighten the threaded assembly between the inner shell 52 and the outer shell 51, and then install the limit nut 53 on the upper side of the outer shell 51 until it can no longer be lowered.

[0045] When vulcanization is complete and the mold needs to be separated (dynamic and static) or the product needs to be demolded, if the rubber parts are tightly adhered to the mold core and difficult to remove, such as... Figure 3 As shown, demolding can be achieved quickly by passing a suitable Allen wrench through the through hole of the limiting nut 53, freeing the threaded fit between the inner shell 52 and the outer shell 51. The former can then easily move up and down within the latter. Remove the Allen wrench, connect the air source to the through hole of the limiting nut 53 and continuously supply air. Since the bottom of the inner shell 52 has a significant taper, the compressed air supplied to the air passage will quickly lift the inner shell 52 and directly act on the rubber product through the threaded through hole at the bottom of the outer shell 51, thus achieving demolding.

[0046] In one implementation, when the threads are released to make the threaded connection between the inner shell 52 and the outer shell 51 free, the inner shell 52 is rotated to completely separate its external threaded portion from the internal threaded hole of the outer shell 51.

[0047] The present invention provides a rubber vulcanizing mold that facilitates demolding. Utilizing a specially constructed mold core, it makes full use of compressed air commonly found on the production site to achieve rapid demolding and improve production efficiency. The mold core structure designed in this invention allows for a multi-stage mold design, eliminating concerns about difficulties in demolding due to mold core arrangement. Compared to common manual demolding, the mold designed in this invention significantly reduces the frequency of direct contact between workers and the mold, lowering safety risks.

[0048] The above description only illustrates preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. Any equivalent procedural modifications made using this specification are included within the patent protection scope of this invention.

Claims

1. A rubber vulcanizing mold for easy demolding, characterized in that, include: The static mold includes a lower mold (1) and two intermediate molds (2 and 3) stacked sequentially on the lower mold (1); the intermediate mold (2) is connected to the lower mold (1), and the intermediate mold (3) is limited to the intermediate mold (2) by a positioning pin (6); The moving mold is composed of an upper mold (4), a mold core (5) and a positioning pin (6) connected by an interference fit; wherein, the upper mold (4) is provided with a countersunk hole and a through hole, the top of the mold core (5) is pressed into the countersunk hole by an interference fit, and the upper end of the positioning pin (6) is pressed into the through hole by an interference fit. The middle mold one (2) and the middle mold two (3) are provided with through holes. When the mold is closed, the mold core (5) of the moving mold assembly passes downward through the through hole and together with the stationary mold forms a vulcanization cavity. The mold core (5) includes an outer shell (51), an inner shell (52), and a limiting nut (53); The outer shell (51) is a hollow columnar structure, its outer side is the inner surface of the cavity, the top end is provided with a skirt for interference fit with the upper mold (4), the bottom end opening is provided with an internal thread hole, and the top end opening is provided with an internal thread. The inner shell (52) is a columnar body with an air passage inside. The bottom end has an external threaded part protruding downwards, and the top end has a tool fitting hole that communicates with the upper end of the air passage. The inner shell (52) is assembled in the inner cavity of the outer shell (51), and its external threaded part is engaged with the internal threaded hole at the bottom end of the outer shell (51). The lower end of the air passage radially penetrates the shell of the inner shell (52). The limiting nut (53) is threaded to the internal thread of the opening at the top of the outer shell (51), and has a through hole in the center; In the vulcanized state, the external threaded portion of the inner shell (52) is screwed tightly into the internal threaded hole of the outer shell (51), and the bottom end of the inner shell (52) seals the bottom end opening of the outer shell (51); In the demolded state, the inner shell (52) and the outer shell (51) are disconnected by passing the operating tool through the central through hole of the limiting nut (53). Then, compressed air is introduced through the through hole of the limiting nut (53). The compressed air overflows along the lower port of the air passage, lifts the inner shell (52), and sprays out from the bottom opening of the outer shell (51), acting on the inner surface of the rubber product to achieve demolding.

2. The rubber vulcanizing mold for easy demolding according to claim 1, characterized in that, The length of the external thread at the bottom of the inner shell (52) is equal to the depth of the internal thread hole at the bottom of the outer shell (51), and the side of the bottom of the inner shell (52) is tapered.

3. The rubber vulcanizing mold for easy demolding according to claim 1, characterized in that, The outer surface of the outer shell (51) has a demolding taper, the minor diameter of the internal thread with the top opening is greater than or equal to the inner diameter of the hollow part of the main body of the outer shell (51), and the major diameter of the internal thread hole with the bottom opening is less than or equal to the inner diameter of the hollow part of the main body of the outer shell (51).

4. The rubber vulcanizing mold for easy demolding according to claim 1, characterized in that, The overall thickness of the limiting nut (53) is less than the depth of the internal thread at the top of the outer shell (51), and a slot is machined at the top.

5. The rubber vulcanizing mold for easy demolding according to claim 1, characterized in that, The middle mold (3) is provided with a through hole that is clearance fit with the large end of all the positioning pins (6), and the upper mold (4) is provided with a through hole that is interference fit with the small end of the positioning pins (6).

6. The rubber vulcanizing mold for easy demolding according to claim 1, characterized in that, The mold is configured as a multi-core structure, with multiple mold cores (5) arranged at intervals on the upper mold (4) in an interference fit manner, and multiple through holes provided on the middle mold one (2) and middle mold two (3).

7. The rubber vulcanizing mold for easy demolding according to claim 1, characterized in that, The tool fitting hole is a hexagonal countersunk hole, used to fit with an internal hex wrench.

8. The rubber vulcanizing mold for easy demolding according to claim 2, characterized in that, The air passage in the inner shell (52) is an inverted T-shaped air passage, and the lower end of the air passage radially penetrates the tapered part of the inner shell side.

9. A demolding method using a rubber vulcanizing mold as described in any one of claims 1-8, characterized in that, Includes the following steps: After vulcanization, the moving mold assembly is completely separated from the stationary mold assembly; When the rubber product is adsorbed onto the mold core (5), the operating tool is passed through the through hole of the limit nut (53); and the threaded connection between the inner shell (52) and the bottom of the outer shell (51) is released. Connect the compressed air source to the through hole of the limit nut (53); Compressed air is introduced, which lifts the inner shell (52) and sprays out from the bottom opening of the outer shell (51), thus removing the rubber product.

10. The demolding method for the rubber vulcanizing mold according to claim 9, characterized in that, When disconnecting the threaded connection, rotate the inner shell (52) to completely separate the external threaded part at its bottom end from the internal threaded hole at the bottom end of the outer shell (51).

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