Improved vulcanization process and mold device of lead-free building seismic isolation rubber bearing

Abstract

A vulcanization improvement process for a lead-free building seismic isolation rubber bearing and its mold device. The vulcanization improvement process comprises at least the following four steps after mold closing: step one: low-temperature pressurized exhaust step; step two: high-temperature and high-pressure vulcanization step; step three: high-temperature and low-pressure vulcanization step; step four: low-temperature and low-pressure vulcanization step. The vulcanization mold device comprises an upper mold plate, a middle mold frame, a lower mold plate and a middle hole positioning column. The middle mold frame contains a rubber bearing. The upper mold plate and the lower mold plate are respectively arranged at the upper and lower ends of the middle mold frame, and the two are symmetrical to each other. A step is arranged in the middle of the lower mold plate corresponding to the middle mold frame, and a slot hole adapted to the middle hole positioning column is arranged in the middle of the step. The present invention optimizes the existing compression molding vulcanization process for lead-free building seismic isolation rubber bearings, reduces the appearance defects of the products, realizes the alignment of the sealing plate holes and the positioning of the inner steel plate, shortens the production cycle of the products, and improves the appearance quality and performance stability of the products.

Description

Technical Field

[0001] The invention relates to the technical field of vulcanization of building seismic isolation rubber bearings, and in particular to an improved vulcanization process of a lead-free building seismic isolation rubber bearing and a mold device thereof. Background Art

[0002] Existing lead-free building seismic isolation rubber bearings are generally composed of two layers of sealing steel plates with connecting holes, multiple layers of internal steel plates and a protective layer of rubber. They are thick rubber products. The total height of the bearings can reach several hundred millimeters, and the amount of rubber used in a single product ranges from a few kilograms to several hundred kilograms.

[0003] Generally, the existing lead-free building seismic isolation rubber bearings are manufactured by molding, and there are several common problems in the vulcanization process. First, the traditional mold sets the tear edge groove horizontally, and the outer layer of rubber is a ring-shaped whole. During the mold closing and exhaust stage, the external pressure of the machine suddenly increases, causing the excess rubber to flow to the overflow groove at the same time. However, the overflow groove has a limited flow rate, and a large amount of excess rubber overflows the overflow groove and overflows from the mold parting surface. Due to the high temperature at the upper and lower parting surfaces of the mold, part of the overflowed rubber will begin to solidify at the parting surface, resulting in the mold being unable to lock and the air being unable to be completely discharged. As the vulcanization process progresses, huge internal pressure will be generated inside the product, causing serious edge blasting and bubble problems at the parting surface of the product. Secondly, in the early stage of vulcanization, it takes a long time for the heat to transfer to the inside of the product. The temperature of the inner rubber layer is low, the viscosity is high, and the flow resistance is large. The large mold pressure will cause the internal rubber to flow unevenly. The thickness of different rubber layers or even different positions of the same rubber layer is uneven, causing the internal steel plate to shift. In severe cases, the internal steel plate may even deform or be exposed, seriously affecting the appearance and quality of the product. Thirdly, the mold thickness of the commonly used lead-free building seismic isolation rubber bearings is usually more than 400mm. It takes several hours for the heat to transfer to the inside of the product and reach the effective vulcanization temperature. The synchronization of the temperature rise and vulcanization process of the inner and outer rubber layers of the bearing is very poor, resulting in a large difference in the vulcanization degree and performance of the inner and outer layers of the product.

[0004] At present, there is no solution that can effectively solve the core problems of the vulcanization process of the above-mentioned lead-free building seismic isolation rubber bearings, which makes it impossible to guarantee the appearance quality and performance stability of the bearing products.

[0005] To this end, in view of the above-mentioned defects, the designers of the present invention have devoted themselves to research and design, and combined the experience and achievements of many years in related industries to research and design an improved vulcanization process and mold device for lead-free building seismic isolation rubber bearings to overcome the above-mentioned defects. Summary of the invention

[0006] The purpose of the present invention is to provide an improved vulcanization process for a lead-free building seismic isolation rubber bearing and a mold device thereof, which optimizes the existing compression molding vulcanization process for the lead-free building seismic isolation rubber bearing, reduces the appearance defects of the product, realizes the alignment of the sealing plate holes and the positioning of the inner steel plate, shortens the production cycle of the product, and improves the appearance quality and performance stability of the product.

[0007] To achieve the above object, the present invention discloses a vulcanization process of a lead-free building seismic isolation rubber bearing, which is a variable temperature and variable pressure vulcanization process, characterized in that the clamping vulcanization stage includes at least the following four steps:

[0008] Step 1: Low-temperature pressurized exhaust step, the vulcanization temperature is 110-130℃, and step-by-step pressurized exhaust is adopted to avoid the deformation of the internal steel plate of the product caused by directly applying a large mold clamping pressure when the inner layer of rubber has not yet completely turned into a viscous flow state in the early stage of vulcanization, and the problem that the mold cannot be locked due to the residual rubber discharge in a short period of time far exceeding the overflow flow of the overflow groove and overflowing from the mold parting surface;

[0009] Step 2: high temperature and high pressure vulcanization step, vulcanization temperature 130-150℃, vulcanization pressure 6-20MPa, vulcanization time 0.8-2h, so that the rubber in the scorch period fills the mold cavity, removes excess rubber, uses a higher temperature to effectively shorten the rubber flow filling time, and uses a higher pressure to restrain the greater impact of the rubber with higher viscosity in the early stage on the mold;

[0010] Step 3: High temperature and low pressure vulcanization step, with a vulcanization temperature of 130-150°C, a vulcanization pressure of 2-8MPa, and a vulcanization time of 3-8h, so that the inner layer of rubber continues to vulcanize rapidly and removes part of the internal pressure generated inside the product during the vulcanization process to prevent subsequent pressure reduction from causing defects such as edge blasting on the product;

[0011] Step 4: Low temperature and low pressure vulcanization step, the vulcanization temperature is 110-130℃, the vulcanization pressure is 2-8MPa, and the vulcanization time is 0.5-1.5h. With the help of more waste heat accumulated inside the product, the inside of the product continues to be fully vulcanized.

[0012] Among them: in step one, the stepped pressurized exhaust first uses 2-8MPa pressure for exhaust for 4-10min, then uses 4-14MPa pressure for exhaust for 6-16min, and then uses 6-20MPa pressure for exhaust for 4-10min, exhausts 4-6 times per minute to remove internal air, and finally uses 6-20MPa pressure to lock the mold.

[0013] Among them: before vulcanization, the sealing plate and the internal steel plate can be placed on a trolley for preheating at 50-90°C, and the empty mold can be pressed on a vulcanizer for sufficient preheating.

[0014] Also disclosed is a vulcanizing mold device for a lead-free building seismic isolation rubber bearing, which at least comprises an upper mold plate, a middle mold frame, a lower mold plate and a middle hole positioning column, and is characterized in that:

[0015] The middle mold frame is a square frame with a rubber support placed in it. Auxiliary holes for calibrating the sealing plate connecting holes are respectively arranged on two opposite sides of the upper bottom surface of the middle mold frame. The upper mold plate and the lower mold plate are respectively arranged at the upper and lower ends of the middle mold frame, and the two are symmetrical to each other. A step is arranged in the middle of the lower mold plate corresponding to the middle mold frame. The size of the step is consistent with the bottom surface of the rubber support. A slot hole adapted to the middle hole positioning column is arranged in the middle of the step. Two lower sealing plate connecting hole positioning guide columns are symmetrically arranged on both sides of the slot hole. A plurality of vertical tearing grooves are symmetrically arranged on the side surfaces of the periphery of the step.

[0016] Wherein: the lower template is provided with outwardly extending glue overflow grooves corresponding to each tearing edge groove around the step, and positioning pins corresponding to the pin holes at the bottom of the middle mold frame are respectively provided at the four corners of the lower template.

[0017] Wherein: the center hole positioning column is a hollow cylindrical steel component with internal threads.

[0018] Wherein: a layer of silicone oil or lubricating oil is evenly coated on the outer side surface of the center hole positioning column.

[0019] Among them: it also includes a calibration fixture for the sealing plate holes, which is a rectangular steel beam. A middle through hole adapted to the middle hole positioning column is provided at the center of the beam, and four guide columns are provided at intervals at the bottom of the beam. The two middle guide columns cooperate with the bolt holes of the upper sealing plate for positioning, and the two guide columns close to the outside cooperate with the auxiliary holes provided on the two opposite sides of the middle mold frame for positioning.

[0020] Among them: it also includes a demoulding tool, which includes an upper demoulding frame and a lower demoulding frame. The upper demoulding frame and the lower demoulding frame are hollow cylindrical structures. The inner diameter of the lower demoulding frame is between the diameters of the middle mold frame and the rubber support, and the inner diameter of the upper demoulding frame is slightly smaller than the diameter of the rubber support.

[0021] Among them: it also includes a pin pulling tool, which includes a crossbeam, a support rod, a bolt gasket assembly and a rotating rod. The crossbeam is rectangular, and support rods and bolt gasket assemblies are arranged at the lower sides. A through hole is provided in the middle. The rotating rod can be rotatably inserted into the through hole. The lower part of the rotating rod is provided with an external thread to threadably engage with the internal thread of the center hole positioning column to realize the pulling out of the hollow positioning column.

[0022] From the above content, it can be known that the improved vulcanization process of the lead-free building seismic isolation rubber bearing and the mold device thereof of the present invention have the following effects:

[0023] 1. A variable temperature and pressure vulcanization method is proposed. First, the pressure is increased step by step, the internal air is removed, and the mold is locked. Then the high pressure is maintained and the temperature is increased so that the rubber fills the mold cavity and the product is basically formed. Then the temperature is maintained and the pressure is lowered to allow the inner layer of rubber to continue to vulcanize and remove part of the internal pressure generated during vulcanization. Finally, the temperature is lowered and the large amount of residual heat inside the product is used to continue vulcanization. The products produced by the above optimized process are completely vulcanized, and the appearance quality and product performance meet the use requirements.

[0024] 2. The alignment of the upper and lower sealing plate holes of the product is achieved, solving the problems of internal steel plate offset and edge blasting.

[0025] 3. With the help of mold structure design and sealing plate hole calibration fixture, the upper and lower sealing plate holes of the product are aligned, which facilitates the installation of the product.

[0026] 4. The problem of internal steel plate offset during vulcanization is solved by the constraint of the center hole positioning column, and demoulding is made easier with the help of demoulding tooling.

[0027] 5. The rubber bearing products produced by the above-mentioned improved vulcanization process and its mold device have smooth and flat parting surfaces and no appearance defects left by the needle-shaped or linear exhaust holes opened in the mold.

[0028] The details of the present invention can be obtained from the following description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The schematic diagram of the structure of the lower template and the middle hole positioning column of the present invention is shown.

[0030] Figure 2 The schematic diagram of the structure of the calibration fixture for sealing plate holes in the present invention is shown.

[0031] Figure 3 The schematic diagram of the structure of the demoulding tooling in the present invention is shown.

[0032] Figure 4 The schematic diagram of the structure of the pin pulling tool in the present invention is shown.

[0033] Figure 5 The schematic diagram of the structure of the LNR(Ⅰ)-D520×201-G4 natural rubber bearing manufactured by the present invention is shown.

[0034] Fig. 6A and Figure 6B A schematic diagram of film cutting of a LNR(Ⅰ)-D520×201-G4 natural rubber bearing made using the present invention is shown. DETAILED DESCRIPTION

[0035] The invention relates to an improved vulcanization process for a lead-free building seismic isolation rubber bearing.

[0036] The improved vulcanization process of the lead-free building seismic isolation rubber bearing is a variable temperature and variable pressure vulcanization process. The entire vulcanization process includes at least the following four steps after the clamping vulcanization stage:

[0037] Step 1: Low-temperature pressurized exhaust step, the vulcanization temperature is 110-130℃, and stepped pressurized exhaust is adopted. Specifically, the stepped pressurized exhaust first uses 2-8MPa pressure to exhaust for 4-10min, then uses 4-14MPa pressure to exhaust for 6-16min, and then uses 6-20MPa pressure to exhaust for 4-10min, exhausts 4-6 times per minute to remove internal air, and finally uses 6-20MPa pressure to lock the mold.

[0038] In the most preferred embodiment, the vulcanization temperature in the low-temperature pressurized exhaust step is 130°C, and the stepped pressurized exhaust first uses 4MPa pressure for exhaust for 5 minutes, then uses 6MPa pressure for exhaust for 8 minutes, and then uses 8MPa pressure for exhaust for 5 minutes, exhausts 4-6 times per minute to remove the internal air, and finally uses 8MPa pressure to lock the mold, which can achieve the best effect;

[0039] And the step-by-step pressurized exhaust is adopted to avoid the defects of the mold being unable to be locked due to the direct application of large mold clamping pressure when the inner layer of rubber has not yet completely turned into a viscous flow state in the early stage of vulcanization, which may cause deformation of the steel plate inside the product and overflow from the mold parting surface due to the residual rubber discharge in a short period of time far exceeding the flow rate of the overflow groove;

[0040] Step 2: high temperature and high pressure vulcanization step, the vulcanization temperature is 130-150°C, the vulcanization pressure is 6-20MPa, and the vulcanization time is 0.8-2h (the vulcanization temperature is 140°C, the vulcanization pressure is 8MPa, and the vulcanization time is 1h in the most preferred embodiment), so that the rubber in the scorch period fills the mold cavity, and the excess rubber is removed. A higher temperature is used to effectively shorten the rubber flow filling time, and a higher pressure is used to restrict the greater impact of the rubber with higher viscosity in the early stage on the mold;

[0041] In step two, high temperature and high pressure can make the rubber in the scorching stage fill the mold cavity, remove excess rubber and internal air, and basically finalize the product. A higher vulcanization pressure is used mainly because the rubber flowing and filling the mold cavity will have a greater impact on the mold cavity wall. If the pressure is insufficient, the excess rubber will also overflow the overflow groove and solidify on the upper and lower parting surfaces of the mold, and the mold cannot be locked. A higher vulcanization temperature is used mainly because the temperature transfer is fast, which can effectively shorten the flow and filling time of the rubber, so that the inner layer of rubber can quickly reach the effective vulcanization stage.

[0042] Step 3: high temperature and low pressure vulcanization step, with a vulcanization temperature of 130-150°C, a vulcanization pressure of 2-8MPa, and a vulcanization time of 3-8h (in the most preferred embodiment, the vulcanization temperature is 140°C, the vulcanization pressure is 4MPa, and the vulcanization time is 4h), so that the inner layer of rubber continues to vulcanize rapidly and removes part of the internal pressure generated inside the product during the vulcanization process to prevent subsequent pressure reduction from causing defects such as edge blasting on the product;

[0043] In step three, the inner rubber layer in the effective vulcanization stage continues to be vulcanized quickly and effectively, and part of the internal pressure generated inside the product during the vulcanization process is removed. The use of a higher vulcanization temperature is mainly due to the fact that the inner rubber layer has completely filled the mold cavity at this stage, and the inner and outer rubber layers are effectively vulcanized at the same time. According to the time-temperature equivalence principle, increasing the vulcanization temperature can effectively shorten the vulcanization time; at the same time, a higher vulcanization temperature will cause a large amount of cross-linking reaction of the inner rubber layer at this stage under the action of the vulcanizer, thereby generating a huge internal pressure, and the clamping pressure continues to increase. Using a lower vulcanization pressure can offset the problem of increasing clamping pressure caused by internal pressure, ensure the stability and safety of the vulcanization process, and prevent defects such as edge blasting caused by excessive internal pressure of the product when it is ejected from the mold.

[0044] Step 4: low temperature and low pressure vulcanization step, the vulcanization temperature is 110-130°C, the vulcanization pressure is 2-8MPa, and the vulcanization time is 0.5-1.5h (in the most preferred embodiment, the vulcanization temperature is 130°C, the vulcanization pressure is 4MPa, and the vulcanization time is 40min). With the help of more waste heat accumulated inside the product, the inside of the product continues to be fully vulcanized.

[0045] In step 4, the product interior is fully vulcanized by taking advantage of the residual heat accumulated inside the product. The lower vulcanization pressure is used mainly because the internal pressure of the product can continue to be released when the temperature of the mold and the outer layer of the product decreases, so that the edge blasting problem will not occur when the mold is removed due to the large internal and external pressure difference; the lower vulcanization temperature is used mainly because a large amount of heat is accumulated inside the product in the first three stages, and the temperature is reduced and the product can still meet the vulcanization needs for several hours even after the product is removed from the mold. At the same time, the lower vulcanization temperature can also save a certain amount of energy consumption.

[0046] Through the above improved process Figure 5 , Fig. 6A and Figure 6B The LNR(Ⅰ)-D520×201-G4 natural rubber bearing shown in the figure has been successfully applied. The products produced have no appearance defects such as edge blasting and bubbles, and have passed the product performance test of the Engineering Seismic Research Center of Guangzhou University. The test is carried out in accordance with GB20688.1-2006 "Rubber Bearings Part 1: Test Methods for Seismic Isolation Rubber Bearings" and GB20688.3-2006 "Rubber Bearings Part 3: Building Seismic Isolation Rubber Bearings". The test results are: σv =12MPa, vertical performance K v =1771kN / mm, γ = 100% horizontal performance, equivalent stiffness K h =1.04kN / mm, ultimate shear deformation>400%.

[0047] The design of the rubber bearing is carried out in accordance with GB20688.3-2006 "Rubber Bearing Part 3: Building Seismic Isolation Rubber Bearing". The total height of the product is 201mm, the working surface diameter is 520mm, and the side of the product is completely wrapped by the outer protective rubber. The sealing plate has a diameter of 500mm and a thickness of 21mm, and is provided with 12 symmetrically distributed M16 bolt holes. The inner steel plate has a diameter of 500mm and a thickness of 3.4mm, and a circular hole with a diameter of 30mm is provided in the center. Each product is provided with 2 sealing plates at the upper and lower ends and 19 inner steel plates located between the sealing plates. The inner rubber material is natural rubber, which has good comprehensive properties such as dynamic, compression deformation resistance, fatigue resistance, and damping characteristics. There are 20 layers of inner rubber arranged between the two inner steel plates and between the upper and lower sealing plates and the inner steel plate. The inner rubber has a diameter of 500mm and a thickness of 4.7mm. The outer protective rubber material is natural rubber, which has good comprehensive properties such as strength, shear resistance, fatigue resistance, and aging resistance. The thickness of the outer rubber is 10mm. The adhesive adopts Chemlok's 6108 and 205 environmentally friendly double coating system, and the coating process is roller coating.

[0048] Preferably, before vulcanization, the sealing plate and the inner steel plate can be placed on a trolley and preheated at 50-90°C, and the empty mold can be pressed on a vulcanizer to be fully preheated.

[0049] Therefore, through the above method, the product can be completely vulcanized, and the appearance quality and product performance can meet the use requirements.

[0050] The present invention also relates to a vulcanization mold device for a lead-free building seismic isolation rubber bearing, which at least comprises an upper mold plate, a middle mold frame, a lower mold plate and a middle hole positioning column. Figure 1 and Figure 2 The material of the three-plate mold is 45# steel, which can realize the positioning of the rubber bearing 10 during vulcanization. Figure 2 The middle mold frame 12 is a square frame, in which the rubber support 10 is placed, and the upper and lower ends are provided with circular flanges, and the two opposite sides are provided with auxiliary holes 121 for calibrating the sealing plate connection holes, and the periphery is provided with two bolt holes 122 for mold hoisting. The upper mold plate and the lower mold plate 11 are respectively arranged at the upper and lower ends of the middle mold frame 12, and the two are symmetrical to each other, so Figure 1Only the lower template is shown as an example. A step 111 is set in the middle of the lower template 11 corresponding to the middle mold frame 12. The size of the step is consistent with the bottom surface of the rubber support 10. A slot hole adapted to the middle hole positioning column 13 is set in the middle of the step 111, and two lower sealing plate connecting hole positioning guide columns 112 are symmetrically set on both sides of the slot hole. A plurality of vertical tearing grooves 113 are symmetrically set on the side surfaces of the periphery of the step 111. The lower template 11 is provided with outwardly extending glue overflow grooves 114 corresponding to each tearing groove 113 around the step 111, and positioning pins 115 corresponding to the pin holes at the bottom of the middle mold frame 12 are respectively provided at the four corners of the lower template 11.

[0051] Preferably, the center hole positioning column 13 is made of P20 steel, which is a hollow cylinder with internal threads. When in use (molding), a layer of silicone oil or lubricating oil can be evenly applied to the outer side of the center hole positioning column 12 to facilitate removal from the product with the pin removal tool after demolding.

[0052] Optionally, a calibration fixture 14 for sealing plate holes may also be included, see Figure 2 The calibration fixture 14 includes a rectangular crossbeam made of 45# steel. A middle through hole adapted to the middle hole positioning column 13 is provided at the center of the crossbeam. Four guide columns are provided at intervals at the bottom of the crossbeam. The spacing between the two middle guide columns and the middle through hole is 160mm, which is used for positioning in conjunction with the bolt holes of the upper sealing plate. The spacing between the two guide columns near the outside and the middle hole is 300mm, which is used for positioning in conjunction with the auxiliary holes 121 provided on the two opposite sides of the middle mold frame. When in use, first pass the middle through hole of the calibration fixture through the middle hole positioning column, then match the two middle guide columns with the two bolt holes on the upper sealing plate on the same diameter, and rotate the fixture to drive the upper sealing plate to rotate, so that the two guide columns near the outside of the fixture are just aligned with the auxiliary holes on the two opposite sides of the middle mold frame, that is, the five points are in line, to achieve accurate and stable calibration positioning.

[0053] Optionally, a demoulding tool may also be included, such as Figure 3 As shown, the demolding tooling includes an upper demolding frame 15 and a lower demolding frame 16, which are made of 45# steel. The upper demolding frame 15 and the lower demolding frame 16 are hollow cylindrical structures. The inner diameter of the lower demolding frame is between the diameters of the middle mold frame and the rubber support, and the inner diameter of the upper demolding frame is slightly smaller than the diameter of the rubber support. Preferably, the inner diameter of the lower demolding frame is 600mm, and the inner diameter of the upper demolding frame is 350mm.

[0054] Optionally, it may also include a pin removal tool, such as Figure 4As shown, the pin extraction tool comprises a crossbeam 17, a support rod 18, a bolt gasket assembly 19 and a rotating rod 20. The crossbeam 17 is rectangular, and support rods 18 and bolt gasket assemblies 19 are arranged at the lower sides. A through hole is provided in the middle, and the rotating rod 20 can be rotatably penetrated in the through hole. The lower part of the rotating rod 20 is provided with an external thread to threadably engage with the internal thread of the center hole positioning column to realize the extraction of the hollow positioning column. The support rod has two height options of 100mm and 200mm, and the bolt gasket assembly can also realize fine adjustment in height.

[0055] Before vulcanization, the empty mold can be pressed on the vulcanizing machine and preheated at 130°C for more than 4 hours. The sealing plate and the internal steel plate can be placed on a special trolley and preheated at 80°C for 1 hour. A vibrating cutter can be used to preform the required inner layer film and protective layer rubber.

[0056] When installing the mold, use a crane to place the mold on the workbench, remove the upper template and the middle mold frame in turn, first place the lower sealing plate in the preset slot of the lower template, and the two bolt holes on the same diameter of the lower sealing plate fall on the two positioning guide pillars preset in the lower template, then pass the middle hole positioning pillar through the middle hole of the lower sealing plate and set it in the preset slot of the lower template, pass the inner rubber and the inner steel plate through the middle hole positioning pillar and stack them alternately, pass the upper sealing plate through the middle hole positioning pillar and place it, then wrap the outer protective rubber around the outer side of the inner rubber and the inner steel plate, the outer protective rubber should be pre-formed, leaving only 2 nodes at the corresponding positions of the upper and lower mold tearing grooves, finally, drop the middle mold frame, align the upper and lower sealing plate holes with the help of the sealing plate hole calibration fixture, drop the upper template, and complete the mold installation.

[0057] When demolding, use a crane to remove the mold and open the upper and lower templates. First, use the crane to place the lower demolding frame on the machine table, place the middle mold frame with the vulcanized product inside on the lower demolding frame, and place the upper demolding frame on the vulcanized product. Then, use the clamping pressure of the vulcanizer to take out the vulcanized product with the center hole locating column, and then use the pin pulling tool to screw the center hole locating column out of the vulcanized product.

[0058] The inner steel plate is positioned by the center hole positioning column, and the upper and lower cover plate installation bolt hole alignment is achieved by the cover plate hole calibration fixture. A three-plate mold with a vertical tear edge groove is designed and the amount of outer glue above the mold overflow groove is reduced to facilitate the discharge of air and excess glue. Special demoulding tooling and pin removal tooling are designed to facilitate the removal of the product and the center hole positioning column. A variable temperature and pressure vulcanization process is proposed and the steel plate is pre-heated to solve the problems of bubbles and fried edges on the parting surface of the product, shorten the production cycle of the product, and improve the appearance quality and performance stability of the product.

[0059] The sealing plate hole calibration fixture can achieve complete alignment of the bolt holes for connecting the upper and lower sealing plates, which is convenient for installation and construction. The fixture structure is designed as a steel square beam. A through hole is provided at the center of the beam to match the center hole positioning column. Four guide columns are provided at the bottom of the beam. The two middle guide columns are used in conjunction with the sealing plate bolt holes, and the two guide columns near the outside are used in conjunction with the holes in the center of the two opposite sides of the middle mold. When using, first pass the center hole of the calibration fixture through the center hole positioning column, and then match the two middle guide columns of the fixture with the two bolt holes on the same diameter of the upper sealing plate. Rotate the fixture to drive the upper sealing plate to rotate, so that the two guide columns near the outside of the fixture are just aligned with the preset holes on the two opposite sides of the middle mold, that is, the five points are collinear.

[0060] It can be seen that the advantages of the present invention are:

[0061] 1. A variable temperature and pressure vulcanization method is proposed. First, the pressure is increased step by step, the internal air is removed, and the mold is locked. Then the high pressure is maintained and the temperature is increased so that the rubber fills the mold cavity and the product is basically formed. Then the temperature is maintained and the pressure is lowered to allow the inner layer of rubber to continue to vulcanize and remove part of the internal pressure generated during vulcanization. Finally, the temperature is lowered and the large amount of residual heat inside the product is used to continue vulcanization. The products produced by the above optimized process are completely vulcanized, and the appearance quality and product performance meet the use requirements.

[0062] 2. The alignment of the upper and lower sealing plate holes of the product is achieved, solving the problems of internal steel plate offset and edge blasting.

[0063] 3. With the help of mold structure design and sealing plate hole calibration fixture, the upper and lower sealing plate holes of the product are aligned, which facilitates the installation of the product.

[0064] 4. The problem of internal steel plate offset during vulcanization is solved by the constraint of the center hole positioning column, and demoulding is made easier with the help of demoulding tooling.

[0065] 5. The rubber bearing products produced by the above-mentioned improved vulcanization process and its mold device have smooth and flat parting surfaces and no appearance defects left by the needle-shaped or linear exhaust holes opened in the mold.

[0066] It is obvious that the above description and record are only examples and are not intended to limit the disclosure, application or use of the present invention. Although the embodiments have been described in the embodiments and described in the drawings, the present invention is not limited to the specific examples of the teachings of the present invention as the best mode currently considered by the drawings and described in the embodiments, and the scope of the present invention will include any embodiment falling within the previous description and the attached claims.

Claims

1. An improved vulcanization process for lead-free building seismic isolation rubber bearings: a variable temperature and variable pressure vulcanization process, characterized in that The clamping vulcanization stage includes at least the following four steps: Step 1: Low-temperature pressurized exhaust step, the vulcanization temperature is 110-130℃, and step-by-step pressurized exhaust is adopted. The step-by-step pressurized exhaust first uses 2-8MPa pressure for exhaust for 4-10min, then uses 4-14MPa pressure for exhaust for 6-16min, and then uses 6-20MPa pressure for exhaust for 4-10min, exhausts 4-6 times per minute to remove internal air, and finally uses 6-20MPa pressure to lock the mold to avoid the deformation of the internal steel plate of the product caused by directly applying a large mold clamping pressure when the inner layer of rubber has not completely turned into a viscous flow state in the early stage of vulcanization, and the problem that the mold cannot be locked due to the residual rubber discharge in a short period of time far exceeding the overflow tank flow and overflowing from the mold parting surface; Step 2: high temperature and high pressure vulcanization step, vulcanization temperature 130-150℃, vulcanization pressure 6-20MPa, vulcanization time 0.8-2h, so that the rubber in the scorch period fills the mold cavity, removes excess rubber, uses a higher temperature to effectively shorten the rubber flow filling time, and uses a higher pressure to restrain the greater impact of the rubber with higher viscosity in the early stage on the mold; Step 3: high temperature and low pressure vulcanization step, the vulcanization temperature is 130-150℃, the vulcanization pressure is 2-8MPa, and the vulcanization time is 3-8h, so that the inner layer of rubber continues to vulcanize quickly and removes part of the internal pressure generated inside the product during the vulcanization process to prevent the subsequent pressure drop from causing edge blasting defects on the product; Step 4: Low temperature and low pressure vulcanization step, the vulcanization temperature is 110-130℃, the vulcanization pressure is 2-8MPa, and the vulcanization time is 0.5-1.5h. With the help of more waste heat accumulated inside the product, the inside of the product continues to be fully vulcanized.

2. The improved vulcanization process of the lead-free building seismic isolation rubber bearing according to claim 1, characterized in that: Before vulcanization, the sealing plate and the inner steel plate can be placed on a trolley for preheating at 50-90°C, and the empty mold can be pressed on a vulcanizer for sufficient preheating.

3. A vulcanization mold device for the improved vulcanization process of the lead-free building seismic isolation rubber bearing according to claim 1 or 2, which at least comprises an upper mold plate, a middle mold frame, a lower mold plate and a middle hole positioning column, characterized in that: The middle mold frame is a square frame with a rubber support placed in it. Auxiliary holes for calibrating the sealing plate connecting holes are respectively arranged on two opposite sides of the upper bottom surface of the middle mold frame. The upper mold plate and the lower mold plate are respectively arranged at the upper and lower ends of the middle mold frame, and the two are symmetrical to each other. A step is arranged in the middle of the lower mold plate corresponding to the middle mold frame. The size of the step is consistent with the bottom surface of the rubber support. A slot hole adapted to the middle hole positioning column is arranged in the middle of the step. Two lower sealing plate connecting hole positioning guide columns are symmetrically arranged on both sides of the slot hole. A plurality of vertical tearing grooves are symmetrically arranged on the side surfaces of the periphery of the step.

4. The vulcanizing mold device for the lead-free building seismic isolation rubber bearing according to claim 3, characterized in that: The lower template is provided with outwardly extending glue overflow grooves corresponding to each tearing edge groove around the step, and positioning pins corresponding to the pin holes at the bottom of the middle mold frame are respectively provided at the four corners of the lower template.

5. The vulcanizing mold device of the lead-free building seismic isolation rubber bearing according to claim 3, characterized in that: The center hole positioning column is a hollow cylindrical steel component provided with an internal thread.

6. The vulcanizing mold device of the lead-free building seismic isolation rubber bearing according to claim 3, characterized in that: A layer of silicone oil or lubricating oil is evenly coated on the outer side of the center hole positioning column.

7. The vulcanizing mold device for the lead-free building seismic isolation rubber bearing according to claim 3, characterized in that: It also includes a calibration fixture for the sealing plate holes, which is a rectangular steel beam. A middle through hole adapted to the middle hole positioning column is provided at the center of the beam. Four guide columns are provided at intervals at the bottom of the beam. The two middle guide columns cooperate with the bolt holes of the upper sealing plate for positioning, and the two guide columns close to the outside cooperate with the auxiliary holes provided on the two opposite sides of the middle mold frame for positioning.

8. The vulcanizing mold device for the lead-free building seismic isolation rubber bearing according to claim 3, characterized in that: It also includes a demoulding tool, which includes an upper demoulding frame and a lower demoulding frame. The upper demoulding frame and the lower demoulding frame are hollow cylindrical structures. The inner diameter of the lower demoulding frame is between the diameters of the middle mold frame and the rubber support, and the inner diameter of the upper demoulding frame is slightly smaller than the diameter of the rubber support.

9. The vulcanizing mold device of the lead-free building seismic isolation rubber bearing according to claim 3, characterized in that: It also includes a pin pulling tool, which includes a crossbeam, a support rod, a bolt gasket assembly and a rotating rod. The crossbeam is rectangular, and support rods and bolt gasket assemblies are arranged at the lower sides. A through hole is provided in the middle. The rotating rod can be rotatably inserted into the through hole. The lower part of the rotating rod is provided with an external thread, which is threadedly engaged with the internal thread of the center hole positioning column to realize the pulling out of the hollow positioning column.

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