Vacuum energy-saving tire mold protection structure

Abstract

The application provides a vacuum energy-saving tire mold protection structure and relates to the technical field of vacuum tire molds. The U-shaped sealing ring provided with an air bag at each connecting end face improves the air tightness of the tire cavity during the vacuum and high-pressure material injection processes, reduces vacuum leakage and raw material overflow, and reduces the energy consumption of the vacuum pump operation. The setting of the expansion joint and the sealing groove and the chamfer with an edge angle greater than 45 degrees make the inner wall of the tire form an annular reinforcing rib to enhance the mechanical strength of the corresponding part of the tire, and the chamfer avoids shearing and scratching of the inner wall of the tire during contraction and reduces the contraction resistance. The annular air bag is arranged continuously in the circumferential direction of the U-shaped sealing ring, which ensures the circumferential consistency of the sealing contact pressure and improves the sealing reliability. The annular folding joint in the middle of the U-shaped sealing ring makes the deformation of the U-shaped sealing ring controllable and concentrated during the repeated inflation and deflation processes, avoids irregular plastic deformation or fatigue cracking, and prolongs the service life of the U-shaped sealing ring.

Description

Technical Field

[0001] This invention relates to the field of vacuum tire mold technology, and in particular to a vacuum energy-saving tire mold protective structure. Background Technology

[0002] Tire molds are crucial equipment in the tire vulcanization process, and their sealing performance directly affects the vulcanization quality and production efficiency. During tire vulcanization, a vacuum environment needs to be established inside the mold, and it must withstand high-pressure injection. Therefore, sealing structures must be installed between the various connecting components of the mold to prevent gas leakage and material spillage. Existing tire mold sealing structures typically include multiple components such as a central disc, a telescopic disc, an outer disc, and an outer mold. Sealing rings are used at the connection faces between these components to seal the tire cavity. The reliability and durability of the sealing rings have a decisive impact on the overall sealing effect of the mold.

[0003] Existing tire mold sealing rings generally suffer from easy wear and short service life. On one hand, the tire vulcanization process requires the mold interior to be in a high-temperature environment of 150℃ to 180℃. Rubber sealing rings used under high temperature and pressure for extended periods are prone to aging and cracking, leading to loss of sealing performance. Localized high temperatures within the sealing pair can also easily cause localized wear of the sealing ring, resulting in seal failure. On the other hand, during the opening and closing of the tire mold, there is relative movement between the components, and the sealing rings are subjected to repeated compression and friction under dynamic working conditions. For existing central mechanism sealing structures, the seals are mostly installed once and are inconvenient to install and disassemble. The vulcanizing machine's upper ring operates frequently, causing the seals to wear easily. Once worn, they are unusable, and replacement and installation are difficult. Furthermore, existing technologies involve numerous sealing points and assembly steps, making leakage easy to occur during actual production. It is also difficult to pinpoint the exact location of the leak, often requiring the replacement of all sealing rings, significantly increasing spare parts costs and maintenance workload. Simultaneously, existing sealing rings are under constant compression, making them prone to permanent deformation or loss of elasticity under high temperature and continuous pressure, further exacerbating wear and failure. The aforementioned problems seriously affect the sealing reliability of tire molds, increase the frequency of downtime maintenance and production costs, and therefore urgently require a vacuum-type energy-saving tire mold protection structure. Summary of the Invention

[0004] To address at least one of the aforementioned technical shortcomings, this invention provides a vacuum-type energy-saving tire mold protective structure, comprising: a central disc; at least one telescopic disc, an outer disc, and an outer mold arranged sequentially from the inside to the outside at the top and bottom of the central disc; the interiors of the two outer molds forming a sealed tire cavity with the central disc, the telescopic disc, and the outer disc; and metal seals provided at the connections between the tire cavity and the central disc and the telescopic disc, the connections between the tire cavity and the two adjacent telescopic discs, the connections between the tire cavity and the telescopic disc and the outer disc, the connections between the tire cavity and the outer disc and the outer mold, and the connections between the tire cavity and the two outer molds.

[0005] Furthermore, the metal seal includes a U-shaped sealing ring, and an air bladder is fixedly connected inside the U-shaped sealing ring.

[0006] Furthermore, expansion joints are provided between the connecting end faces of the telescopic disc and the central disc, between the connecting end faces of the telescopic disc and the outer disc, between the connecting end faces of the outer disc and the outer mold, and between the connecting end faces of the two outer molds. A sealing groove is provided on the side of the expansion joint near the tire cavity, and a U-shaped sealing ring is fixedly connected inside the sealing groove. The U-shaped sealing ring between the connecting end faces of the outer disc and the outer mold is fixed inside the sealing groove of the outer disc.

[0007] Furthermore, the edges of the sealing groove that contact the tire cavity are all chamfered with an angle greater than 45°.

[0008] Furthermore, the airbag is an annular airbag, which is continuously arranged in the U-shaped groove of the U-shaped sealing ring along the circumference of the U-shaped sealing ring. When the airbag is inflated, it drives the two side walls of the U-shaped sealing ring to expand outward so as to press against the two opposite side walls of the sealing groove respectively.

[0009] Furthermore, four limiting rods are fixedly connected to the bottom and top end faces of the central plate, and corresponding limiting holes are opened on the telescopic plate, the outer plate, and the outer mold.

[0010] Furthermore, the length of the limiting rod is greater than the opening width of the outer mold.

[0011] Furthermore, the U-shaped sealing ring has an annular folded seam in the middle.

[0012] Furthermore, the airbag is connected to an external air source via a pressure regulating valve assembly. The pressure regulating valve assembly is configured to: output a first pressure to the airbag during the initial heating stage of tire vulcanization to pre-tighten the seal; and output a second pressure higher than the first pressure to the airbag during the constant temperature and pressure holding stage of the middle and later stages of tire vulcanization to compensate for the expansion of the sealing gap caused by the thermal expansion of the metal mold.

[0013] Furthermore, the outer wall surface of the U-shaped sealing ring in contact with the sealing groove is covered with a flexible graphite metal composite coating with a thickness of 0.2 mm to 0.5 mm. The flexible graphite metal composite coating is used to reduce the frictional resistance of the U-shaped sealing ring retraction when the airbag deflates.

[0014] Beneficial effects: 1. The U-shaped sealing rings containing air bladders at each connection end face of this invention improve the airtightness of the tire cavity during vacuum and high-pressure injection processes, reduce vacuum leakage and material overflow, and lower the energy consumption of the vacuum pump. The expansion joints and sealing grooves, as well as the chamfered edges of the sealing grooves with an angle greater than 45°, form annular reinforcing ribs on the inner wall of the tire to enhance the mechanical strength of the corresponding parts of the tire. The chamfer also avoids shearing and scratching of the inner wall of the tire during contraction and reduces contraction resistance. The annular air bladders are continuously arranged along the circumference of the U-shaped sealing ring, ensuring the circumferential consistency of the sealing contact pressure and improving sealing reliability. The annular folded seam in the middle of the U-shaped sealing ring makes the deformation of the U-shaped sealing ring controllable and concentrated during repeated inflation and deflation, avoiding irregular plastic deformation or fatigue cracking. The airbag and pressure regulating valve assembly, along with the phased pressure output configuration, effectively compensate for differences in mold thermal expansion, maintaining stable sealing contact pressure throughout the vulcanization cycle. The flexible graphite-metal composite coating covering the outer wall of the U-shaped seal reduces frictional resistance during retraction, preventing jamming under high-temperature conditions. The limiting rod on the central disc engages with the limiting holes on the telescopic disc, outer disc, and outer mold. The length of the limiting rod is greater than the opening width of the outer mold, ensuring coaxiality and repeatability of each component during mold opening and closing, and fully exposing the central disc, telescopic disc, and outer disc after mold opening. The axial contraction of the central disc, telescopic disc, and outer disc after mold opening, combined with the chamfering, pushes open the inner wall of the tire.

[0015] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the entire invention.

[0017] Figure 2 This is an isometric view of the outer disk of the present invention.

[0018] Figure 3 This is the invention Figure 1 Enlarged view of point A.

[0019] exist Figures 1 to 3 The correspondence between the component names or lines and the attached drawing numbers is as follows: 1. Center plate, 2. Telescopic plate, 3. Outer plate, 4. Outer mold, 5. U-shaped sealing ring, 6. Airbag, 7. Tire cavity, 8. Expansion joint, 9. Sealing groove. Detailed Implementation

[0020] Combined with appendix Figures 1 to 3A vacuum-type energy-saving tire mold protective structure includes: a central disk 1, at least one telescopic disk 2, an outer disk 3 and an outer mold 4 arranged sequentially from the inside to the outside at the top and bottom of the central disk 1, the two outer molds 4 forming a sealed tire cavity 7 between the interior of the two outer molds 4 and the central disk 1, the telescopic disk 2 and the outer disk 3, and metal seals are provided at the connection points of the tire cavity 7 with the central disk 1 and the telescopic disk 2, the connection points of the tire cavity 7 with the two adjacent telescopic disks 2, the connection points of the tire cavity 7 with the telescopic disk 2 and the outer disk 3, the connection points of the tire cavity 7 with the outer disk 3 and the outer mold 4, and the connection points of the tire cavity 7 with the two outer molds 4.

[0021] In practical implementation, the central platen 1 is located at the central axis of the mold. At least one telescopic platen 2, an outer platen 3, and an outer mold 4 are sequentially arranged from the inside out at the top and bottom of the central platen 1. The components at the top, from top to bottom, are the top outer mold 4, the top outer platen 3, at least one telescopic platen 2, and the central platen 1; the components at the bottom, from bottom to top, are the bottom outer mold 4, the bottom outer platen 3, at least one telescopic platen 2, and the central platen 1. The bottom outer mold 4 and the top outer mold 4 move towards the central platen 1 from the bottom direction and the top direction respectively until they close. The inner walls of the two outer molds 4, together with the outer walls of the central platen 1, the telescopic platen 2, and the outer platen 3, form a sealed space, which is the tire cavity 7. The tire cavity 7 is used to contain tire raw materials and form a tire shape during the vulcanization process. The outer mold 4 has a vacuum hole and a pipeline for injecting tire raw materials. The vacuum hole is connected to an external vacuum pump, and the pipeline for injecting tire raw materials is connected to an external feeding system.

[0022] Metal seals are provided at the connections of the tire cavity 7 with the central disc 1 and the telescopic disc 2, the tire cavity 7 with the two adjacent telescopic discs 2, the tire cavity 7 with the telescopic disc 2 and the outer disc 3, the tire cavity 7 with the outer disc 3 and the outer mold 4, and the tire cavity 7 with the two outer molds 4. The function of the metal seals is to block the leakage path of gas or raw material inside the tire cavity 7 along the connecting end faces of each component during the vacuum environment and high-pressure injection process of tire vulcanization. In the mold-closed state, the bottom outer mold 4 and the top outer mold 4 are pressed together by the external mold-closing force. The metal seals undergo elastic deformation under the action of the clamping force, filling the microscopic gaps between the connecting end faces, thereby achieving the sealing of the tire cavity 7. When the tire vulcanization is completed, the external mold-closing force is released, and the bottom outer mold 4 and the top outer mold 4 move to the bottom and top directions respectively to open, and the completed tire is taken out from the central disc 1, the telescopic disc 2, and the outer disc 3.

[0023] Furthermore, the metal seal includes a U-shaped sealing ring 5, and an air bladder 6 is fixedly connected inside the U-shaped sealing ring 5.

[0024] In practical implementation, the metal seal includes a U-shaped sealing ring 5, with an airbag 6 fixedly connected inside the U-shaped sealing ring 5. The U-shaped sealing ring 5 is a ring-shaped structure made of metal with a U-shaped cross-section, the U-shaped opening facing away from the tire cavity 7. The airbag 6 is fixedly connected inside the U-shaped groove of the U-shaped sealing ring 5, and the specific fixing method can be adhesive bonding or mechanical fitting. The airbag 6 is connected to an external air source and control valve assembly through an air passage.

[0025] Before the tire vulcanization process begins, the bottom outer mold 4 and the top outer mold 4 are closed, and the telescopic discs 2, outer discs 3, outer molds 4, and center disc 1 form a preliminary fit under axial clamping force. At this time, the air bladder 6 is in an uninflated or low-pressure state, and the U-shaped sealing ring 5 is only subjected to mechanical clamping force. Subsequently, compressed gas is injected into the air bladder 6, which expands and pushes the two side walls of the U-shaped sealing ring 5 outward, so that the two outer walls of the U-shaped sealing ring 5 are tightly fitted to the two opposite side walls of the sealing groove 9, further enhancing the sealing effect. During the tire vulcanization process, a vacuum environment is established in the tire cavity 7 through the vacuum hole on the outer mold 4, and tire raw materials are injected through the pipeline for injecting tire raw materials. The air bladder 6 is continuously inflated to ensure that the U-shaped sealing ring 5 can maintain a reliable seal under high temperature, vacuum, and pressure change conditions.

[0026] When the tire vulcanization is complete and it needs to be removed, the gas in the airbag 6 is first released through the control valve assembly, causing the airbag 6 to contract. The two side walls of the U-shaped sealing ring 5 retract inwards due to their own elasticity. At this time, the contact pressure between the U-shaped sealing ring 5 and the side wall of the sealing groove 9 is significantly reduced or the contact is lost. Then, the bottom outer mold 4 and the top outer mold 4 open in opposite directions. After the central disc 1, telescopic disc 2, and outer disc 3 lose their axial clamping force, they can undergo relative displacement and contraction, creating a loose gap between the finished tire and the mold components, making it easier to remove the tire from the central disc 1, telescopic disc 2, and outer disc 3.

[0027] Furthermore, expansion joints 8 are provided between the connecting end faces of the telescopic disc 2 and the central disc 1, between the connecting end faces of the telescopic disc 2 and the outer disc 3, between the connecting end faces of the outer disc 3 and the outer mold 4, and between the connecting end faces of the two outer molds 4. A sealing groove 9 is provided on the side of the expansion joint 8 near the tire cavity 7. A U-shaped sealing ring 5 is fixedly connected inside the sealing groove 9. The U-shaped sealing ring 5 between the connecting end faces of the outer disc 3 and the outer mold 4 is fixed inside the sealing groove 9 of the outer disc 3.

[0028] In practical implementation, expansion joints 8 are provided between the connecting end faces of the telescopic disc 2 and the central disc 1, between the connecting end faces of the telescopic disc 2 and the outer disc 3, between the connecting end faces of the outer disc 3 and the outer mold 4, and between the connecting end faces of the two outer molds 4. The expansion joints 8 are axial clearance channels reserved between adjacent components. Their width can decrease under mold closing pressure or recover after mold opening, allowing relative contraction displacement between the central disc 1, telescopic disc 2, and outer disc 3 in the mold-opening state. A sealing groove 9 is provided on the side of the expansion joint 8 near the tire cavity 7. The sealing groove 9 is an annular groove machined on the end face of the corresponding component, and its cross-sectional shape matches the outer contour of the U-shaped sealing ring 5. The U-shaped sealing ring 5 is fixedly connected inside the sealing groove 9, specifically by embedding the bottom of the U-shaped sealing ring 5 into the bottom of the sealing groove 9, or by using an interference fit to keep it within the sealing groove 9. The U-shaped sealing ring 5 between the connecting end faces of the outer disk 3 and the outer mold 4 is fixed in the sealing groove 9 opened on the end face of the outer disk 3, rather than fixed on the outer mold 4. In this way, the U-shaped sealing ring 5 moves with the outer disk 3 when the mold is opened, and will not interfere with the mold opening action.

[0029] The function of the expansion joint 8 is to provide movement space for the axial contraction of the central disc 1, expansion disc 2, and outer disc 3 after mold opening. In the mold-closed state, the external mold-closing force presses the components axially, compressing the width of the expansion joint 8 to a minimum. In the mold-open state, the external mold-closing force is released, and the components can achieve relative displacement through the expansion of the expansion joint 8. The function of the sealing groove 9 is to position the U-shaped sealing ring 5 on the side of the expansion joint 8 closest to the tire cavity 7, so that the U-shaped sealing ring 5 directly faces the vacuum and pressure environment inside the tire cavity 7, thereby blocking the communication path between the expansion joint 8 and the tire cavity 7 and preventing gas or raw materials inside the tire cavity 7 from leaking to the outside of the mold through the expansion joint 8.

[0030] Furthermore, the edges of the sealing groove 9 that contact the tire cavity 7 are all chamfered with an angle greater than 45°.

[0031] In practical implementation, the edges of the sealing groove 9 that contact the tire cavity 7 are all machined with a chamfer angle greater than 45°. This chamfer is located at the opening edge of the sealing groove 9, that is, at the edge where the inner wall of the tire cavity 7 transitions to the side wall of the sealing groove 9. The chamfer angle is a value between 45° and 90°, for example, 60° or 75°.

[0032] During the tire vulcanization stage, tire material is injected into the tire cavity 7 and fills the entire space of the cavity 7. Under pressure, the tire material enters the chamfered area of ​​the sealing groove 9 that contacts the tire cavity 7. Due to the presence of the chamfer, after the tire material solidifies in this area, it forms a wedge-shaped or beveled annular protrusion structure, which constitutes the annular reinforcing rib of the tire's inner wall. The annular reinforcing rib enhances the mechanical strength and deformation resistance of the tire in the corresponding area of ​​the bead or sidewall.

[0033] During the mold opening stage, after the airbag 6 depressurizes and contracts, and the bottom and top outer molds 4 open, the center disc 1, telescopic disc 2, and outer disc 3 need to contract axially to detach from the tire's inner wall. Since the chamfer at the contact edge between the sealing groove 9 and the tire cavity 7 forms an inclined surface rather than a right-angled step, when the mold components move in the detachment direction, the chamfered surface applies a gradual thrust to the corresponding area of ​​the tire's inner wall. This thrust has an axial component, which helps to push the tire away from the mold components. Simultaneously, the chamfered structure avoids the shearing or scratching effect of right-angled edges on the tire's inner wall during contraction, protecting the integrity of the tire's inner wall. The presence of the chamfer makes the contraction process between the center disc 1, telescopic disc 2, and outer disc 3 smoother, reducing contraction resistance.

[0034] Furthermore, the airbag 6 is an annular airbag, which is continuously arranged in the U-shaped groove of the U-shaped sealing ring 5 along the circumference of the U-shaped sealing ring 5. When the airbag 6 is inflated, it drives the two side walls of the U-shaped sealing ring 5 to expand outward to press against the two opposite side walls of the sealing groove 9 respectively.

[0035] In practical implementation, the airbag 6 is an annular airbag, continuously arranged circumferentially within the U-shaped groove of the U-shaped sealing ring 5. The annular airbag is made of an elastic material, such as high-temperature resistant rubber or a flexible metal bellows, and its internal cavity is connected to an external air passage through one or more air nozzles. When the airbag 6 is inflated, the annular airbag expands axially outward. Because the annular airbag is confined within the U-shaped groove of the U-shaped sealing ring 5, the expansion force acts directly on the inner walls of both sides of the U-shaped sealing ring 5, driving the two side walls of the U-shaped sealing ring 5 to expand outward. The two side walls respectively abut against the two opposite side walls of the sealing groove 9, forming a double-sided contact seal. The expansion force provided by the airbag 6 is evenly distributed along the entire circumferential length of the U-shaped sealing ring 5, thus ensuring that the two side walls of the U-shaped sealing ring 5 can evenly adhere to the side walls of the sealing groove 9, avoiding insufficient local sealing pressure.

[0036] When the airbag 6 is in the deflation and contraction state, the volume of the annular airbag decreases, reducing or eliminating the thrust on the two side walls of the U-shaped sealing ring 5. Under the action of its own metallic elastic restoring force, the two side walls of the U-shaped sealing ring 5 retract inward, disengaging from the side walls of the sealing groove 9 or significantly reducing the contact pressure. This mechanism of actively controlling the sealing contact state allows for rapid release of the sealing constraint when mold opening is required, reducing the movement resistance between mold components, thereby facilitating the contraction of the central disc 1, the telescopic disc 2, and the outer disc 3, and the opening of the outer mold 4.

[0037] Furthermore, four limiting rods are fixedly connected to the bottom and top end faces of the central disc 1, and corresponding limiting holes are opened on the telescopic disc 2, the outer disc 3 and the outer mold 4.

[0038] In practical implementation, four limiting rods are fixedly connected to the bottom and top end faces of the central disk 1. The four limiting rods are evenly distributed along the circumference on the end face of the central disk 1, and the axial direction of the limiting rods is parallel to the central axis of the central disk 1. The telescopic disk 2, the outer disk 3, and the outer mold 4 are all provided with corresponding limiting holes. The limiting holes are through holes that pass through the corresponding components, and their inner diameter is slightly larger than the outer diameter of the limiting rod, so that the limiting rod can slide freely along the axial direction within the limiting hole.

[0039] During the mold closing process, the bottom outer mold 4 and the top outer mold 4 move towards the central disk 1 from the bottom direction and the top direction, respectively. During the movement, the limiting holes on the outer mold 4 first engage with the limiting rods, and then the limiting holes on the outer disk 3 and the telescopic disk 2 successively engage with the limiting rods. The limiting rods guide the moving parts, ensuring that the bottom outer mold 4, the bottom outer disk 3, the bottom telescopic disk 2 and the central disk 1, as well as the top outer mold 4, the top outer disk 3, and the top telescopic disk 2, maintain coaxiality during axial movement, avoiding jamming or misalignment of the sealing surfaces due to component misalignment.

[0040] During the mold opening process, the bottom outer mold 4 and the top outer mold 4 slide open in opposite directions along the limiting rod, and the telescopic disc 2 and the outer disc 3 can also slide axially along the limiting rod. The limiting rod constrains the axial position of the telescopic disc 2, the outer disc 3 and the outer mold 4, so that these components will not wobble radially during movement, ensuring the repeatability and positioning accuracy of the mold after multiple opening and closing.

[0041] Furthermore, the length of the limiting rod is greater than the opening width of the outer mold 4.

[0042] In practice, the length of the limiting rod is greater than the opening width of the outer mold 4. The opening width of the outer mold 4 refers to the axial distance between the opposite end faces of the bottom and top outer molds 4 after they are fully opened in opposite directions from their closed state. The length of the limiting rod is designed so that when the bottom and top outer molds 4 are fully opened to their limit positions, the end of the limiting rod remains inside the limiting holes of the bottom and top outer molds 4 and will not come out of the limiting holes. At the same time, in this fully opened state, the entire outer contour of the center plate 1, the telescopic plate 2, and the outer plate 3 is fully exposed axially in the open space between the bottom and top outer molds 4.

[0043] This structural design allows operators or robots to directly access the center disc 1, telescopic disc 2, and outer disc 3 from the side of the mold, facilitating the gripping and removal of the finished tires. Since the center disc 1, telescopic disc 2, and outer disc 3 are fully exposed, there is no obstruction from the outer mold 4 between the tire bead area and the mold components, making it easier to apply demolding force to the tire. Furthermore, the design of the retaining rod ensures that the telescopic disc 2, outer disc 3, and outer mold 4 are always guided and constrained by the retaining rod throughout the entire mold opening and tire removal process, preventing components from falling off or becoming difficult to reset.

[0044] Furthermore, the U-shaped sealing ring 5 has an annular folded seam in the middle.

[0045] In practical implementation, the U-shaped sealing ring 5 has an annular folded seam in its middle. The folded seam is an annular weak groove or annular cut machined circumferentially at the bottom of the U-shape of the U-shaped sealing ring 5. The depth of the folded seam is less than the wall thickness of the U-shaped sealing ring 5 and does not penetrate the wall surface of the U-shaped sealing ring 5. The folded seam divides the bottom of the U-shape of the U-shaped sealing ring 5 into two parts: a bottom wall on the side closer to the tire cavity 7 and a bottom wall on the side farther from the tire cavity 7.

[0046] When the airbag 6 inflates, the expansion force acts on the two side walls and bottom of the U-shaped sealing ring 5. Due to the presence of the folded seam, the U-shaped bottom of the U-shaped sealing ring 5 can undergo controllable opening deformation along the folded seam, thereby allowing the two side walls to achieve a greater outward expansion range and enhancing the sealing effect against the side walls of the sealing groove 9. When the airbag 6 deflates and contracts, the U-shaped sealing ring 5 needs to return from the expanded state to the initial contracted state. The folded seam provides a preset bending deformation position, so that the deformation recovery of the U-shaped sealing ring 5 is concentrated at this position, avoiding irregular plastic deformation or fatigue cracking of the U-shaped sealing ring 5 during repeated inflation and deflation. The folded seam makes the contraction deformation of the U-shaped sealing ring 5 directional and repeatable, improving the service life and operational reliability of the seal.

[0047] Furthermore, the airbag 6 is connected to an external air source via a pressure regulating valve assembly. The pressure regulating valve assembly is configured to: output a first pressure to the airbag 6 during the initial heating stage of tire vulcanization to pre-tighten the seal; and output a second pressure higher than the first pressure to the airbag during the constant temperature and pressure holding stage of the middle and later stages of tire vulcanization to compensate for the expansion of the sealing gap caused by the thermal expansion of the metal mold.

[0048] In practice, the airbag 6 is connected to an external air source via a pressure regulating valve assembly. The external air source can be compressed air or nitrogen. The pressure regulating valve assembly includes at least one pressure regulating valve, a directional control valve, and a pressure sensor. The operating sequence of the pressure regulating valve assembly is linked to the control system of the tire vulcanization process.

[0049] During the initial heating stage of tire vulcanization, the temperature and pressure inside the tire cavity 7 have not yet reached the process set values, and the metal components of the mold are at their initial temperature state, with relatively small thermal expansion. The pressure regulating valve group controls the output of a first pressure to the airbag 6, with the first pressure ranging from 0.2 MPa to 0.4 MPa. Under this pressure, the airbag 6 expands, driving the U-shaped sealing ring 5 to form an initial sealing contact with the sidewall of the sealing groove 9, which is sufficient to maintain the airtightness of the tire cavity 7 during the vacuuming and filling processes.

[0050] During the mid-to-late stage of tire vulcanization, in the constant temperature and pressure holding phase, the temperature inside the tire cavity 7 reaches the vulcanization temperature, such as 150°C to 180°C, causing thermal expansion of the various metal components of the mold. Due to the differences in size and thermal expansion coefficients of the central disc 1, telescopic disc 2, outer disc 3, and outer mold 4, the width of the sealing groove 9 will increase slightly due to thermal expansion, resulting in an expansion of the sealing gap between the U-shaped sealing ring 5 and the sidewall of the sealing groove 9. At this time, the pressure regulating valve group automatically switches the pressure output to the airbag 6 to a second pressure, which is higher than the first pressure, for example, 0.6MPa to 0.8MPa. The airbag 6 expands further under the higher pressure, pushing the sidewalls of the U-shaped sealing ring 5 to produce a greater expansion, thereby compensating for the increased sealing gap due to the thermal expansion of the metal mold and maintaining the sealing contact pressure within the effective range.

[0051] During the cooling and mold opening stage after tire vulcanization, the pressure regulating valve group controls the airbag 6 to release pressure and release the sealing contact. This staged pressure control method allows the sealing system to actively adapt to the thermal deformation state of the mold at different process stages, ensuring the vacuum and sealing of the tire cavity 7 throughout the entire vulcanization cycle.

[0052] Furthermore, the outer wall surface of the U-shaped sealing ring 5 in contact with the sealing groove 9 is covered with a flexible graphite metal composite coating with a thickness of 0.2 mm to 0.5 mm. The flexible graphite metal composite coating is used to reduce the frictional resistance of the U-shaped sealing ring 5 retracting when the airbag 6 deflates and contracts.

[0053] In practical implementation, the outer wall surface of the U-shaped sealing ring 5 in contact with the sealing groove 9 is covered with a flexible graphite-metal composite coating with a thickness of 0.2 mm to 0.5 mm. The flexible graphite-metal composite coating is formed on both outer wall surfaces of the U-shaped sealing ring 5 through electroplating or chemical plating processes. Its specific composition consists of graphite particles dispersed within a metal matrix. The metal matrix can be nickel or a nickel-based alloy, and the volume fraction of the graphite particles is 15% to 30%.

[0054] During the inflation phase of the airbag 6, the outer walls of the U-shaped sealing ring 5 expand outward under the expansion force of the airbag 6 and fit tightly against the sidewalls of the sealing groove 9. The metal substrate of the flexible graphite metal composite coating provides sufficient strength and wear resistance to withstand the compressive stress on the sealing contact surface. During the depressurization and contraction phase of the airbag 6, the two sidewalls of the U-shaped sealing ring 5 need to detach from the sidewalls of the sealing groove 9 and retract to their initial position under their own elastic action. Because the flexible graphite metal composite coating contains graphite particles, and graphite has self-lubricating properties, during the relative sliding process between the sidewalls of the U-shaped sealing ring 5 and the sidewalls of the sealing groove 9, the graphite particles can form an extremely thin solid lubricating film on the contact interface, significantly reducing the coefficient of friction. This reduces the frictional resistance when the U-shaped sealing ring 5 retracts, allowing the U-shaped sealing ring 5 to retract smoothly without jamming even after multiple cycles of use under high temperature conditions. Meanwhile, the thickness of the flexible graphite metal composite coating is controlled within the range of 0.2mm to 0.5mm, which ensures the lubrication effect without affecting the fitting accuracy and sealing effect of the U-shaped sealing ring 5 and the sealing groove 9 due to excessive coating thickness.

[0055] Apply an inner release agent and an outer release agent to the inner wall of the tire cavity 7.

[0056] After the tire vulcanization is complete and the airbag 6 is depressurized and contracted, the bottom outer mold 4 and the top outer mold 4 move in opposite directions along the limiting rod to the fully open position. At this time, the center plate 1, the telescopic plate 2 and the outer plate 3 are fully exposed and are all located in the internal space area of ​​the completed tire. The inner wall surface of the tire is in contact with the outer wall surface of the center plate 1, the outer wall surface of the telescopic plate 2 and the outer wall surface of the outer plate 3.

[0057] As the airbag 6 has depressurized and contracted, the two side walls of the U-shaped sealing ring 5 retract inward under their own elasticity, releasing the contact pressure between the U-shaped sealing ring 5 and the side wall of the sealing groove 9. At this time, the expansion joints 8 between the telescopic disc 2 and the central disc 1, between adjacent telescopic discs 2, between the telescopic disc 2 and the outer disc 3, and between the outer disc 3 and the outer mold 4 return to the preset gap value when they were not compressed, and the components are in a free state where they can slide relative to each other along the axial direction. The limiting rod constrains the radial position of each component, ensuring that each component moves only along the axial direction without deviation.

[0058] Along the central axis of the central disk 1, an axial thrust is applied to the top set of telescopic disks 2 and outer disks 3 in the direction of the central disk 1, and simultaneously, an axial thrust is applied to the bottom set of telescopic disks 2 and outer disks 3 in the direction of the central disk 1. Guided by the limiting rod, the telescopic disks 2 and outer disks 3 move axially towards the central disk 1. The width of the expansion joint 8 between the top telescopic disk 2 and the top outer disk 3 decreases, as does the width of the expansion joint 8 between the top telescopic disk 2 and the central disk 1; the width of the expansion joint 8 between the bottom telescopic disk 2 and the bottom outer disk 3 also decreases, as does the width of the expansion joint 8 between the bottom telescopic disk 2 and the central disk 1. Through this axial contraction action, the overall combined length of the central disk 1, telescopic disks 2, and outer disks 3 in the axial direction decreases.

[0059] Operators use robotic arms or pull-out mechanisms to smoothly remove the tire from the central disc 1, telescopic disc 2, and outer disc 3 along the axial direction.

Claims

1. A vacuum-type energy-saving tire mold protective structure, characterized in that: include: The center plate (1) has at least one telescopic plate (2), an outer plate (3) and an outer mold (4) arranged sequentially from the inside to the outside at the top and bottom of the center plate (1). The interior of the two outer molds (4) forms a sealed tire cavity (7) with the center plate (1), the telescopic plate (2) and the outer plate (3). Metal seals are provided at the connection points of the tire cavity (7) with the center plate (1) and the telescopic plate (2), the connection points of the tire cavity (7) with the two adjacent telescopic plates (2), the connection points of the tire cavity (7) with the telescopic plate (2) and the outer plate (3), the connection points of the tire cavity (7) with the outer plate (3) and the outer mold (4), and the connection points of the tire cavity (7) with the two outer molds (4).

2. A vacuum-type energy-saving tire mold protective structure according to claim 1, characterized in that: The metal seal includes a U-shaped sealing ring (5), and an air bladder (6) is fixedly connected inside the U-shaped sealing ring (5).

3. A vacuum-type energy-saving tire mold protective structure according to claim 2, characterized in that: Expansion joints (8) are provided between the connecting end faces of the telescopic disc (2) and the central disc (1), between the connecting end faces of the telescopic disc (2) and the outer disc (3), between the connecting end faces of the outer disc (3) and the outer mold (4), and between the connecting end faces of the two outer molds (4). A sealing groove (9) is provided on the side of the expansion joint (8) near the tire cavity (7). A U-shaped sealing ring (5) is fixedly connected inside the sealing groove (9). The U-shaped sealing ring (5) between the connecting end faces of the outer disc (3) and the outer mold (4) is fixed inside the sealing groove (9) of the outer disc (3).

4. A vacuum-type energy-saving tire mold protective structure according to claim 3, characterized in that: The edges of the sealing groove (9) that contact the tire cavity (7) are all provided with chamfers with an angle greater than 45°.

5. A vacuum-type energy-saving tire mold protective structure according to claim 4, characterized in that: The airbag (6) is an annular airbag. The annular airbag is continuously arranged in the U-shaped groove of the U-shaped sealing ring (5) along the circumference of the U-shaped sealing ring (5). When the airbag (6) is inflated, it drives the two side walls of the U-shaped sealing ring (5) to expand outward to press against the two opposite side walls of the sealing groove (9) respectively.

6. A vacuum-type energy-saving tire mold protective structure according to claim 5, characterized in that: Four limiting rods are fixedly connected to the bottom and top end faces of the central disk (1), and corresponding limiting holes are opened on the telescopic disk (2), outer disk (3) and outer mold (4).

7. A vacuum-type energy-saving tire mold protective structure according to claim 6, characterized in that: The length of the limiting rod is greater than the opening width of the outer mold (4).

8. A vacuum-type energy-saving tire mold protective structure according to claim 7, characterized in that: The U-shaped sealing ring (5) has an annular folded seam in the middle.

9. A vacuum-type energy-saving tire mold protective structure according to claim 8, characterized in that: The airbag (6) is connected to an external air source through a pressure regulating valve group. The pressure regulating valve group is configured to: output a first pressure to the airbag (6) in the initial heating stage of tire vulcanization to pre-tighten the seal; and output a second pressure higher than the first pressure to the airbag in the constant temperature and pressure holding stage of the middle and late stages of tire vulcanization to compensate for the expansion of the sealing gap caused by the thermal expansion of the metal mold.

10. A vacuum-type energy-saving tire mold protective structure according to claim 9, characterized in that: The outer wall surface of the U-shaped sealing ring (5) in contact with the sealing groove (9) is covered with a flexible graphite metal composite coating with a thickness of 0.2 mm to 0.5 mm. The flexible graphite metal composite coating is used to reduce the frictional resistance of the U-shaped sealing ring (5) when the airbag (6) is depressurized and contracted.

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