A vulcanization forming mold and a vulcanization forming process for a high-precision thin-wall long rubber cylinder

Abstract

The application provides a vulcanization forming die and a vulcanization forming process for a high-precision thin-wall long rubber cylinder, the vulcanization forming die comprises a lower die, a die core and an upper die which are sequentially installed in a vulcanization device from bottom to top, the vulcanization device can drive the upper die to vertically lift to open the vulcanization forming die or pressurize the vulcanization forming die after the upper die is closed, the die core is fixedly connected with the upper die in a detachable mode, and positioning support frames for downward limiting of the die core are symmetrically arranged at the left and right ends of the upper cavity of the lower die. The vulcanization forming die and the vulcanization forming process for the high-precision thin-wall long rubber cylinder solve the problems of wall thickness out-of-tolerance and eccentricity which are prone to occur in the prior art, and avoid uneven wall thickness, size out-of-tolerance, product eccentricity and uneven misalignment at the joint line of the product.

Description

Technical Field

[0001] This invention relates to the field of rubber processing technology, and more specifically, to a high-precision vulcanization molding die and vulcanization molding process for thin-walled long rubber cylinders. Background Technology

[0002] Rubber tubing products are typically made of silicone rubber. They are formed by further trimming, cutting, and polishing after a first-stage vulcanization molding and a second-stage shaping. In the first-stage molding process, the vulcanization molding mold usually adopts a structure of upper and lower molds plus a mold core. Due to the high precision of the product, the positioning pins of the mold need to be fitted with zero clearance.

[0003] In existing technologies, when operating vulcanization molding molds, the mold is first removed entirely from the vulcanization equipment. Then, an overhead crane is used to open and remove the upper mold. Next, the overhead crane lifts the mold core and places it on a nearby support. After the mold core is completely covered with rubber, the overhead crane lifts it again and lowers it into the lower mold cavity. Finally, the overhead crane closes the upper mold. This vulcanization molding process is very prone to wall thickness deviations and eccentricity issues for thin-walled, long rubber cylinders with high dimensional accuracy requirements. For example, for rubber cylinder products with a length exceeding 1300mm, an outer diameter exceeding 150mm, but a wall thickness not exceeding 6.0mm, a wall thickness tolerance of ±0.1mm, and a coaxiality less than 0.2mm, uneven wall thickness, dimensional deviations, product eccentricity, and misalignment / unevenness at the product's seam are frequently observed. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is: the first aspect is to provide a vulcanization molding die for a high-precision thin-walled long rubber tube, which solves the problems of wall thickness deviation and eccentricity that are easy to occur in the prior art for high-precision thin-walled long rubber tubes, and avoids uneven wall thickness, out-of-tolerance dimensions, product eccentricity, and misalignment and unevenness at the product seam of the rubber tube product.

[0005] To address the aforementioned technical problem, this invention provides a high-precision vulcanization molding die for a thin-walled long rubber cylinder, comprising a lower die, a core die, and an upper die installed sequentially from bottom to top within a vulcanization device. The vulcanization device can drive the upper die to vertically lift and lower, thereby opening or closing the vulcanization molding die and applying pressure. The core die is detachably and fixedly connected to the upper die. The lower die has symmetrically arranged positioning support frames at both ends of its upper cavity for downward limiting of the core die.

[0006] Preferably, the detachable fixed connection is as follows: at least two symmetrically distributed hanging connections are used at the left and right ends of the mold core and the upper mold, based on the center of gravity distribution of the mold core, to meet the balance requirements of the mold core during the vertical lifting and lowering process with the upper mold.

[0007] Preferably, the upper mold has a lower cavity, and the left and right ends of the upper mold have symmetrically distributed first lifting rings located directly above the lower cavity.

[0008] Preferably, a pull-out core rod is inserted through the center of one of the left and right ends of the mold core, and the second lifting rings are symmetrically distributed at the left and right ends of the mold core and move downward to avoid the pull-out core rod.

[0009] Preferably, the lower mold, the mold core, and the upper mold all adopt a self-heating method using electric heating tubes, and at least the upper cavity and the lower cavity are coated with Teflon.

[0010] The technical problem to be solved by the present invention is as follows: In the second aspect, a vulcanization molding process for high-precision thin-walled long rubber tubes is proposed, which solves the problems of wall thickness deviation and eccentricity that are prone to occur in the prior art for high-precision thin-walled long rubber tubes, and avoids uneven wall thickness, out-of-tolerance dimensions, product eccentricity, and misalignment and unevenness at the product seam of the rubber tube products.

[0011] To address the aforementioned technical problem in the second aspect, this invention proposes a vulcanization molding process for a high-precision thin-walled long rubber tube, using the vulcanization molding die for a high-precision thin-walled long rubber tube as described in any embodiment of the first aspect. The vulcanization molding process includes the following steps:

[0012] S1: The upper mold opens and causes the mold core to suspend in the air;

[0013] S2: Cover the circumferential surface of the mold core with the rubber material;

[0014] S3: Mold closing and pressure applied until vulcanization is completed;

[0015] S4: The upper mold opens again, causing the mold core to suspend in the air;

[0016] S5: After the vulcanized rubber tube product is extracted by pulling out the core rod of the mold core, the cycle continues to step S2.

[0017] Preferably, step S1 includes the following specific operational steps:

[0018] S11: The vulcanizing equipment drives the upper mold to rise vertically to the first preset height;

[0019] S12: The upper mold and the mold core are connected by two double-hook chains;

[0020] S13: The vulcanizing equipment continues to drive the upper mold to rise vertically to the second preset height, so as to suspend the mold core in the air.

[0021] Preferably, step S3 includes the following specific operational steps:

[0022] S31: The vulcanizing equipment drives the upper mold to slowly descend;

[0023] S32: The left and right ends of the mold core smoothly land on the positioning support frame of the lower mold;

[0024] S33: Remove the two double-hook chains;

[0025] S34: The vulcanizing equipment continues to drive the upper mold to slowly descend until it closes with the lower mold;

[0026] S35: Mold closing and pressure applied until vulcanization molding.

[0027] Preferably, step S5 includes the following specific operational steps:

[0028] S51: Pull out a pull-out core rod from one end of the mold core;

[0029] S52: Use the vertical support placed outside the vulcanizing equipment to support the pull-out core rod;

[0030] S53: Remove the double-hook chain near the side of the vertical support;

[0031] S54: Transfer the vulcanized rubber tube product to the pull-out mandrel;

[0032] S55; Reattach the double-hook chain that was removed in step S53;

[0033] S56: The vulcanizing equipment drives the upper mold to rise slowly so that the pull-out mandrel leaves the vertical support;

[0034] S57: Remove the vertical support and pull the rubber tube product out of the pull-out core rod;

[0035] S58: After pushing the pull-out core rod back into the mold core, proceed to step S2 and repeat the cycle.

[0036] Preferably, the high-precision thin-walled long rubber tube has a length exceeding 1300mm, an outer diameter exceeding 150mm, a wall thickness not exceeding 6.0mm, a wall thickness tolerance of ±0.1mm, and a coaxiality of less than 0.2mm.

[0037] Compared with the prior art, the vulcanization molding die and vulcanization process for a high-precision thin-walled long rubber tube described in this invention have the following advantages:

[0038] This invention addresses the issues of excessive wall thickness and eccentricity that commonly occur in high-precision thin-walled long rubber cylinders in existing technologies, thereby preventing uneven wall thickness, dimensional deviations, product eccentricity, and misalignment or unevenness at the product seam in rubber cylinder products. Attached Figure Description

[0039] The accompanying drawings, which constitute a part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0040] Figure 1 This is a three-dimensional structural diagram of a vulcanization molding die for a high-precision thin-walled long rubber tube as described in Embodiment 1 of the present invention, in the mold-closed state.

[0041] Figure 2 for Figure 1 A schematic diagram of one of the three-dimensional structures of the vulcanization molding die in the open state (including rubber tube products);

[0042] Figure 3 This is a schematic diagram of the first three-dimensional structure of an upper mold as described in Embodiment 1 of the present invention;

[0043] Figure 4 This is a schematic diagram of the second three-dimensional structure of an upper mold as described in Embodiment 1 of the present invention;

[0044] Figure 5 This is a schematic diagram of the first three-dimensional structure of a lower mold as described in Embodiment 1 of the present invention;

[0045] Figure 6 This is a schematic diagram of the second three-dimensional structure of a lower mold as described in Embodiment 1 of the present invention;

[0046] Figure 7 This is a first three-dimensional structural diagram of a mold core (excluding rubber tube products) as described in Embodiment 1 of the present invention;

[0047] Figure 8 This is a schematic diagram of the second three-dimensional structure of a mold core (excluding rubber tube products) as described in Embodiment 1 of the present invention;

[0048] Figure 9 This is a schematic diagram of the working state corresponding to step S57 in the vulcanization molding process of a high-precision thin-walled long rubber tube described in Embodiment 2 of the present invention.

[0049] Explanation of reference numerals in the attached figures:

[0050] 1-Lower mold, 11-Upper cavity, 12-Positioning support frame, 2-Mold core, 21-Pull-out core rod, 22-Second lifting ring, 3-Upper mold, 31-Lower cavity, 32-First lifting ring. Detailed Implementation

[0051] To make the above-mentioned objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only some embodiments constituting the present invention, and are only used to explain the present invention and do not constitute a limitation thereof. Unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0052] Example 1

[0053] See Figure 1-8 As shown, the present invention provides a high-precision vulcanization molding die for a thin-walled long rubber cylinder, comprising a lower die 1, a die core 2, and an upper die 3 installed sequentially from bottom to top in a vulcanization device. The vulcanization device can drive the upper die 3 to vertically lift and lower to open or close the vulcanization molding die and apply pressure. The die core 2 and the upper die 3 are detachably fixedly connected. The lower die 1 has symmetrically arranged positioning support frames 12 at the left and right ends of its upper cavity 11 for downward limiting of the die core 2.

[0054] Specifically, as described in the background section, in the existing vulcanization molding process of rubber cylinder products, the entire operation is highly dependent on overhead cranes. However, overhead cranes cannot guarantee the balance of the vulcanization mold during lifting, which can easily cause permanent damage to the mold's locating pins. As a result, mold misalignment leads to problems such as excessive wall thickness and eccentricity in the rubber cylinder products. For high-precision thin-walled long rubber cylinder products, this is even more pronounced: uneven wall thickness, excessive dimensional tolerances, product eccentricity, and unevenness at the product's seam.

[0055] In this invention, the mold core 2 and the upper mold 3 are detachably fixedly connected, and the vertical lifting and lowering of the upper mold 3 are controlled by the vulcanizing equipment. Given that the vulcanizing equipment has a very high flatness, the mold core 2 can be accurately placed into the upper cavity 11 of the lower mold 1 when the mold is closed and pressure is applied, without causing any damage to the positioning pin of the vulcanizing mold. At the same time, the setting of the positioning support frame 12 can ensure that the mold core 2 can be completely in the center position between the lower mold 1 and the upper mold 3, thereby ensuring that the high-precision thin-walled long rubber cylinder has uniform wall thickness and that the coaxiality meets the technical requirements.

[0056] Therefore, the vulcanization molding die for the high-precision thin-walled long rubber tube described in this invention solves the problems of excessive wall thickness and eccentricity that are prone to occur in the prior art for high-precision thin-walled long rubber tubes, and avoids uneven wall thickness, excessive dimensional tolerance, product eccentricity, and misalignment and unevenness at the product seam in rubber tube products.

[0057] Preferably, the detachable fixed connection is as follows: at least two symmetrically distributed hanging connections are used at the left and right ends of the mold core 2 and the upper mold 3, based on the center of gravity distribution of the mold core 2, to meet the balance requirements of the mold core 2 during the vertical lifting and lowering process with the upper mold 3.

[0058] Specifically, the hanging connection is simple, reliable, and easy to operate. Only corresponding lifting rings need to be set at the left and right ends of the mold core 2 and the upper mold 3, based on the center of gravity distribution of the mold core 2. Therefore, the lifting and lowering of the mold core 2, after being connected to the upper mold 3, is entirely accomplished by the vulcanizing equipment, and the mold core 2 does not need to be removed from the vulcanizing equipment. When the mold core 2 needs to be vertically lifted and lowered with the upper mold 3, a double-hook chain can be used to connect the upper mold 3 and the mold core 2; conversely, the double-hook chain can be removed. The entire mold opening and closing pressurization process does not interfere with the vulcanization molding of the rubber compound.

[0059] As a preferred example of the present invention, the upper mold 3 has a lower cavity 31, and the left and right ends of the upper mold 3 are symmetrically distributed with first lifting rings 32 located directly above the lower cavity 31.

[0060] Preferably, a pull-out core rod 21 is inserted through the center of one of the left and right ends of the mold core 2, and the second lifting rings 22 are symmetrically distributed at the left and right ends of the mold core 2 and move downward to avoid the pull-out core rod 21.

[0061] Specifically, during the continuous cycle of the vulcanization molding process, the pull-out mandrel 21 can facilitate the transfer and extraction of the vulcanized rubber cylinder product, while ensuring that the opening and closing of the vulcanization molding die is always inside the vulcanization equipment and is entirely completed by the vulcanization equipment.

[0062] Preferably, the lower mold 1, the mold core 2, and the upper mold 3 are all self-heating methods using electric heating tubes, and at least the upper cavity 11 and the lower cavity 31 are coated with Teflon.

[0063] Specifically, after the vulcanizing mold is opened, the mold core 2 can be suspended in the air via a hanging connection to facilitate the coating of the rubber material onto the circumferential surface of the mold core 2. The self-heating method of the heating element is compatible with the subsequent mold closing and pressurization process, while the Teflon coating facilitates the gas-filled demolding of the rubber material after vulcanization. Of course, the circumferential surface of the mold core 2 can also be coated with Teflon; the specific choice can be optimized according to actual needs.

[0064] Example 2

[0065] See Figure 1-9 As shown, the present invention also proposes a vulcanization molding process for a high-precision thin-walled long rubber tube, using a vulcanization molding die for a high-precision thin-walled long rubber tube as described in Example 1. The vulcanization molding process includes the following steps:

[0066] S1: The upper mold 3 opens and causes the mold core 2 to be suspended in the air;

[0067] S2: Cover the circumferential surface of the mold core 2 with the rubber material;

[0068] S3: Mold closing and pressure applied until vulcanization is completed;

[0069] S4: The upper mold 3 opens again, causing the mold core 2 to be suspended in the air;

[0070] S5: After the vulcanized rubber tube product is extracted by the pull-out core rod 21 of the mold core 2, the cycle continues to step S2.

[0071] Specifically, those skilled in the art will understand that the vulcanization molding process for the high-precision thin-walled long rubber tube proposed in Example 2, when using the vulcanization molding mold for the high-precision thin-walled long rubber tube as described in Example 1, can be understood by referring to the description of the vulcanization molding mold for the high-precision thin-walled long rubber tube in Example 1. Here, for the convenience of those skilled in the art to further understand, some steps in S1-S5 are further elaborated.

[0072] Preferably, step S1 includes the following specific operational steps:

[0073] S11: The vulcanizing equipment drives the upper mold 3 to rise vertically to the first preset height;

[0074] S12: The upper mold 3 and the mold core 2 are suspended and connected by two double-hook chains;

[0075] S13: The vulcanizing equipment continues to drive the upper mold 3 to rise vertically to the second preset height, so as to suspend the mold core 2 in the air.

[0076] Specifically, the operational steps of steps S1 and S4 are essentially the same. The difference lies in whether the mold core 2 has a pre-cured rubber tube product on it. S1 can be understood as the initial operation of the vulcanizing mold, after which the circumference of the mold core 2 can be directly covered with rubber material. Step S4 involves the continuous cyclic operation of the vulcanizing mold, requiring the rubber tube product to be removed before the circumference of the mold core 2 can be covered with rubber material again.

[0077] Preferably, step S3 includes the following specific operational steps:

[0078] S31: The vulcanizing equipment drives the upper mold 3 to slowly fall;

[0079] S32: The left and right ends of the mold core 2 smoothly land on the positioning support frame 12 of the lower mold 1;

[0080] S33: Remove the two double-hook chains;

[0081] S34: The vulcanizing equipment continues to drive the upper mold 3 to slowly fall down until it closes with the lower mold 1;

[0082] S35: Mold closing and pressure applied until vulcanization molding.

[0083] Specifically, in step S2, although the adhesive material covers the circumferential surface of the mold core 2, it is understood that the left and right ends of the mold core 2 are not actually covered. After step S32 and before step S33, the upper mold 3 can continue to be driven to slowly fall to a certain height as needed to facilitate the implementation of step S33.

[0084] Preferably, step S5 includes the following specific operational steps:

[0085] S51: Pull out the pull-out core rod 21 from one end of the mold core 2;

[0086] S52: The pull-out core rod 21 is supported by a vertical bracket placed outside the vulcanizing equipment;

[0087] S53: Remove the double-hook chain near the side of the vertical support;

[0088] S54: Transfer the vulcanized rubber tube product to the pull-out mandrel 21;

[0089] S55; Reattach the double-hook chain that was removed in step S53;

[0090] S56: The vulcanizing equipment drives the upper mold 3 to rise slowly so that the pull-out mandrel 21 leaves the vertical support;

[0091] S57: Remove the vertical support and pull out the rubber tube product from the pull-out core rod 21;

[0092] S58: After pushing the pull-out core rod 21 back into the mold core 2, proceed to step S2 and repeat the cycle.

[0093] Specifically, after step S53, the mold core 2 will still be completely supported and suspended by another double-hook chain on the side away from the vertical support and the vertical support, so as to facilitate the implementation of step S54; while in step S57, after the vertical support is removed, the mold core 2 is only lifted and suspended by two double-hook chains, at which time the rubber tube product can be smoothly extracted from the pull-out core rod 21.

[0094] Preferably, the high-precision thin-walled long rubber tube has a length exceeding 1300mm, an outer diameter exceeding 150mm, a wall thickness not exceeding 6.0mm, a wall thickness tolerance of ±0.1mm, and a coaxiality of less than 0.2mm.

[0095] Specifically, as can be seen from the above, through the vulcanization molding die and vulcanization process of the high-precision thin-walled long rubber tube described in this invention, the upper die 3 and the lower die 1 are always installed on the vulcanization equipment. The opening and closing of the vulcanization molding die is entirely completed by the vulcanization equipment. The lifting and lowering of the die core 2 is also entirely completed by the vulcanization equipment after being connected to the upper die 3 by suspension. The die core 2 does not need to be removed from the vulcanization equipment, which completely avoids the problem of damage to the positioning pin caused by the installation and opening of the die by the overhead crane. This avoids further problems with the rubber tube products, especially for high-precision thin-walled long rubber tubes, where high-precision thin-walled long rubber tubes refer to those with a length exceeding 1300mm, an outer diameter exceeding 150mm, a wall thickness not exceeding 6.0mm, a wall thickness tolerance of ±0.1mm, and a coaxiality of less than 0.2mm.

[0096] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A vulcanization molding process for a high-precision thin-walled long rubber tube, characterized in that, The vulcanization molding process of the high-precision thin-walled long rubber cylinder uses a vulcanization molding mold. The vulcanization molding mold includes a lower mold (1), a mold core (2), and an upper mold (3) installed sequentially from bottom to top in the vulcanization equipment. The vulcanization equipment can drive the upper mold (3) to move vertically up and down to open or close the vulcanization molding mold and apply pressure. The mold core (2) and the upper mold (3) are detachably fixedly connected. The lower mold (1) has symmetrically arranged at both ends of its upper cavity (11) for pressing the mold core. The positioning support frame (12) for downward limiting of the mold core (2); the high-precision thin-walled long rubber tube has a length exceeding 1300mm, an outer diameter exceeding 150mm, a wall thickness not exceeding 6.0mm, a wall thickness tolerance of ±0.1mm, and a coaxiality less than 0.2mm; the mold core (2) has a pull-out core rod (21) inserted at the center of one of its left and right ends, and the second lifting ring (22) is symmetrically distributed at the left and right ends of the mold core (2) and forms a downward avoidance to the pull-out core rod (21); The mold core (2) has a positioning protrusion at least on its left end. With the pull-out core rod (21) as a reference, the second lifting ring (22) is located on the side of the pull-out core rod (21) away from the positioning support frame (12), and the positioning protrusion is located on the side of the pull-out core rod (21) close to the positioning support frame (12). The positioning support frame (12) has an upward-facing positioning groove, and the positioning protrusion can enter the positioning groove along the direction from the upper mold (3) to the lower mold (1). The vulcanization molding process of the high-precision thin-walled long rubber tube includes the following steps: S1: The upper mold (3) opens and causes the mold core (2) to suspend in the air; S2: Cover the circumferential surface of the mold core (2) with the rubber material; S3: Mold closing and pressure applied until vulcanization is completed; S4: The upper mold (3) opens again and causes the mold core (2) to be suspended in the air; S5: After the vulcanized rubber tube product is extracted by the pull-out core rod (21) of the mold core (2), the cycle continues to step S2. Step S3 includes the following specific steps: S31: The vulcanizing equipment drives the upper mold (3) to slowly fall; S32: The left and right ends of the mold core (2) are smoothly lowered onto the positioning support frame (12) of the lower mold (1), and the positioning protrusion enters the positioning groove along the direction from the upper mold (3) to the lower mold (1); S33: Remove the two double-hook chains; S34: The vulcanizing equipment continues to drive the upper mold (3) to slowly fall down until it closes with the lower mold (1); S35: Mold closing and pressure application until vulcanization molding; Step S5 includes the following specific steps: S51: Pull out the pull-out core rod (21) from one end of the mold core (2). S52: The pull-out core rod (21) is supported by a vertical bracket placed outside the vulcanizing equipment; S53: Remove the double-hook chain near the side of the vertical support; S54: Transfer the vulcanized rubber tube product to the pull-out mandrel (21); S55; Reattach the double-hook chain that was removed in step S53; S56: The vulcanizing equipment drives the upper mold (3) to rise slowly so that the pull-out mandrel (21) leaves the vertical support; S57: Remove the vertical support and pull out the rubber tube product from the pull-out core rod (21); S58: After pushing the pull-out core rod (21) back into the mold core (2), proceed to step S2 for cyclical operation.

2. The vulcanization molding process for a high-precision thin-walled long rubber cylinder according to claim 1, characterized in that, The detachable fixed connection is as follows: at least two symmetrically distributed hanging connections are used at the left and right ends of the mold core (2) and the upper mold (3) according to the center of gravity distribution of the mold core (2) to meet the balance requirements of the mold core (2) during the vertical lifting and lowering process with the upper mold (3).

3. The vulcanization molding process for a high-precision thin-walled long rubber tube according to claim 2, characterized in that, The upper mold (3) has a lower cavity (31), and the left and right ends of the upper mold (3) are symmetrically distributed with a first lifting ring (32) located directly above the lower cavity (31).

4. The vulcanization molding process for a high-precision thin-walled long rubber cylinder according to claim 3, characterized in that, The lower mold (1), the mold core (2), and the upper mold (3) all adopt the self-heating method of electric heating tubes, and at least the upper cavity (11) and the lower cavity (31) are coated with Teflon.

5. The vulcanization molding process for a high-precision thin-walled long rubber cylinder according to claim 1, characterized in that, Step S1 includes the following specific steps: S11: The vulcanizing equipment drives the upper mold (3) to rise vertically to the first preset height; S12: The upper mold (3) and the mold core (2) are suspended and connected by two double-hook chains; S13: The vulcanizing equipment continues to drive the upper mold (3) to rise vertically to the second preset height, so as to suspend the mold core (2) in the air.

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