Polyurethane buffer layer structure, preparation process and tire comprising structure

Abstract

The invention provides a polyurethane buffer layer structure, a preparation process and an inflation-free tire comprising the structure, belongs to the technical field of tires, and can solve the problems that a polyurethane inflation-free tire is limited in damping and buffering effects due to the fact that a buffer layer only bears a load in a grounding area, and the material performance is rapidly reduced due to the fact that a large amount of heat is easily generated during high-speed driving. The service performance and the service life of the tire are influenced. The polyurethane buffer layer structure comprises a first rigid component, a second rigid component and a polyurethane buffer layer, the polyurethane buffer layer is bonded between the first rigid component and the second rigid component through vulcanization, and at least one layer of buffer holes are formed in the polyurethane buffer layer. The invention can be applied to the non-pneumatic tire, and the buffering and damping performance, load resistance and high-speed performance of the non-pneumatic tire are improved.

Description

Technical Field

[0001] This invention belongs to the field of tire technology, and particularly relates to a polyurethane buffer layer structure, manufacturing process, and a pneumatic tire containing the structure. Background Technology

[0002] Airless tires are tires that achieve shock absorption and cushioning performance without relying on air pressure. Compared to pneumatic tires, airless tires rely solely on their own material and structural characteristics to provide support and cushioning. Currently, airless tires on the market mainly include solid rubber tires and polyurethane open-structure tires. Polyurethane airless tires typically have the polyurethane buffer layer directly beneath the tread. When the tire bears a load, only the buffer layer near the contact patch participates in the load-bearing process, limiting the shock absorption function to a localized buffer layer structure above the contact patch. Therefore, the buffer layer design must comprehensively consider key indicators such as load-bearing capacity, traction performance, and braking performance. Furthermore, when vehicles travel at speeds exceeding 100 km / h, the polyurethane buffer layer easily generates a large amount of heat, causing a rapid decline in material properties, thus affecting tire performance and lifespan. Therefore, there is a need for a novel polyurethane buffer layer structure for airless tires to improve the cushioning and shock absorption performance, load-bearing capacity, and high-speed performance of existing airless tires. Summary of the Invention

[0003] This invention addresses the technical problems of polyurethane-based airless tires, such as the limited shock absorption effect due to the buffer layer only bearing load in the ground contact area, and the rapid decline in material properties caused by excessive heat generation during high-speed driving, which affects tire performance and lifespan. The invention proposes a polyurethane buffer layer structure, a manufacturing process, and an airless tire incorporating this structure, which has the advantages of improving the shock absorption, load-bearing capacity, and high-speed performance of airless tires.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a polyurethane buffer layer structure, comprising a first rigid member, a second rigid member, and a polyurethane buffer layer, wherein the polyurethane buffer layer is bonded between the first rigid member and the second rigid member by vulcanization, and at least one layer of buffer holes is formed on the polyurethane buffer layer.

[0005] Compared to existing polyurethane-based pneumatic tires where the polyurethane buffer layer is typically placed directly beneath the tread, this invention features a polyurethane buffer layer that is vulcanized and bonded between two rigid structures. Under load, the polyurethane buffer layer as a whole is subjected to pressure, tension, and torsion, resulting in a more uniform and rational stress distribution, thus improving the tire's cushioning, shock absorption, and load-bearing capacity. During high-speed driving, heat is evenly distributed and rapidly dissipated through the rigid structure, enhancing the high-speed performance of the pneumatic tire. The design of the buffer holes optimizes the stress distribution of the polyurethane buffer layer, improving its deformation capacity and elastic recovery performance, further enhancing the tire's cushioning and shock absorption capabilities. This invention's polyurethane buffer layer structure allows for a wider range of buffer hole design options, achieving superior cushioning, shock absorption, high-speed performance, and load-bearing capacity.

[0006] In another aspect, the present invention provides a process for preparing a polyurethane buffer layer structure, comprising the following steps: a positioning and clamping step: fixing a first rigid member and a second rigid member to a first molding platen by a positioning assembly; a pre-gap setting step: setting a positioning auxiliary component between the first molding platen and the positioning assembly to form a pre-gap; a pouring step: pouring polyurethane into the gap formed between the first rigid member and the second rigid member; a mold closing step: assembling a second molding platen and setting a positioning auxiliary component between the second molding platen and the positioning assembly to form a pre-gap; a pressurizing step: installing a pressurizing assembly to connect the first molding platen and the second molding platen; and a vulcanization molding step: releasing the pre-gap and vulcanizing the tooling as a whole to obtain a polyurethane buffer layer structure.

[0007] The positioning and clamping steps of this invention ensure accurate positioning of the first and second rigid components; the pre-gap setting step prevents overflow during pouring; the pouring step fills the buffer layer material; the mold closing step maintains mold closing accuracy and gap stability; the pressurizing step ensures reliable tooling locking; and the vulcanization molding step allows the polyurethane to fully cure and solidify. These process steps work together to precisely control the relative positions and molding dimensions of the first and second rigid components and the polyurethane buffer layer, ensuring uniform polyurethane buffer layer thickness, stable molding quality, and improved bonding strength and structural integrity between the polyurethane buffer layer and the first and second rigid components. Furthermore, the process is highly controllable, produces high product consistency, and is suitable for mass production.

[0008] In one embodiment, a pretreatment step is included before the positioning and clamping step: cleaning the bonding surfaces of the first rigid member and the second rigid member and applying adhesive.

[0009] The pretreatment step can effectively remove impurities and oil stains from the bonding surface, enhance the bonding strength between the polyurethane buffer layer and the inner first rigid component, and improve service life.

[0010] In one embodiment, during the casting step, the polyurethane liquid level is at least flush with the upper edge of the first rigid member near the second molding plate, ensuring that the polyurethane material fully fills the entire gap formed between the first and second rigid members in subsequent steps. This avoids molding defects such as holes or localized looseness in the polyurethane buffer layer due to insufficient filling, and ensures the continuity and integrity of the overall structure of the polyurethane buffer layer.

[0011] In one embodiment, the pre-gap is released during the vulcanization molding step by removing the positioning auxiliary component; the vulcanization temperature is 115-125°C, and the vulcanization time is 24 hours.

[0012] By removing the positioning auxiliary components to release the pre-gap, the volume expansion and flow filling requirements of the polyurethane compound during the curing heating process can be met, avoiding overflow or structural deformation due to insufficient expansion space. This ensures that the polyurethane compound fully fills the gap between the first rigid component and the second rigid component and fits tightly against the inner first rigid component. The setting of the curing temperature and curing time enables the polyurethane to fully cross-link and cure, resulting in a dense and uniform structure that is firmly bonded to the first rigid component.

[0013] In one embodiment, the fabrication process of the polyurethane buffer layer structure is achieved using a polyurethane buffer layer tooling. The polyurethane buffer layer tooling includes multiple tooling units with identical structures. Each tooling unit includes two sets of molding components: a molding component for side molding and buffer hole molding of the polyurethane buffer layer; a positioning component connected to the molding component for clamping and fixing the positions of the first rigid member and the second rigid member; a positioning auxiliary component disposed between the molding platen and the positioning component for forming a pre-gap between the molding platen and the positioning component; and two sets of pressurizing components, each pressurizing component connected to the two sets of molding components within the same tooling unit for mold closing and providing continuous pressure to the polyurethane material.

[0014] Using the tooling of this invention, the polyurethane buffer layer and the inner first rigid component can be formed with high precision, strong bonding and good integrity. The polyurethane buffer layer has a uniform shape and buffer hole size, and the material is dense and defect-free. This significantly improves the structural strength, cushioning and shock absorption performance and high-speed driving stability of the airless tire, ensuring stable and reliable product performance and meeting the needs of large-scale production.

[0015] In one embodiment, each forming component includes a forming plate and a buffer hole bolt, the buffer hole bolt passing through the middle of the corresponding forming plate and extending therefrom, and the extension directions of the buffer hole bolts of the two forming components in each tooling unit are opposite to each other.

[0016] The molding component of this invention can precisely form the buffer hole structure of the polyurethane buffer layer, ensuring that the buffer holes are centered, have consistent diameters, and high coaxiality; it can be molded in one step without secondary processing, effectively improving the molding accuracy and efficiency of the buffer holes, and ensuring that the buffer layer is subjected to uniform stress and has stable and reliable buffering performance.

[0017] In one embodiment, each pressurizing assembly includes two connecting rods, with both ends of each connecting rod passing through pre-set through holes in two oppositely arranged forming pressure plates within the same tooling unit and extending outwards; four compression springs are respectively sleeved on the outwardly extending ends of each connecting rod, and the compression springs are located on the outside of the forming pressure plates.

[0018] The compression spring of this invention can continuously apply a stable clamping force to the molding plate, expel the gas inside the polyurethane material, and prevent the polyurethane from deforming during the vulcanization process, thereby improving the molding quality of the buffer layer.

[0019] In another aspect, the present invention provides a tire including the polyurethane buffer layer structure, which has excellent buffering and shock absorption performance, making the ride more comfortable and stable; strong high-speed driving stability, uniform stress distribution, controllable deformation, and safer operation; outstanding load-bearing performance, high structural strength, reliable bonding, and longer service life.

[0020] In one embodiment, the tire further includes a tread and a tread buffer layer arranged sequentially from the outside to the inside, the tread buffer layer being disposed on the outside of the first rigid member, and the tread buffer layer being at least one layer.

[0021] The tread buffer layer of this invention is located outside the first rigid member, which can absorb road vibration and impact, further improve the tire's cushioning and shock absorption performance, while improving the tread's wear resistance and impact resistance, enhancing the tire's high-speed driving stability and load-bearing performance, and extending the tire's service life.

[0022] Compared with the prior art, the advantages and positive effects of the present invention are as follows: 1. The polyurethane buffer layer structure of the pneumatic tire of the present invention places the polyurethane buffer layer between two rigid structures. When subjected to load, the polyurethane buffer layer as a whole will be subjected to pressure, tension and torsion. The stress on the structure is more uniform and reasonable, which improves the tire's cushioning and shock absorption performance and load-bearing performance. When driving at high speed, the heat can be evenly distributed and quickly dissipated through the rigid structure, which improves the high-speed performance of the pneumatic tire.

[0023] 2. The preparation process of the polyurethane buffer layer structure of the present invention has each step working together to precisely control the relative position and molding size of the first rigid component, the second rigid component and the polyurethane buffer layer, ensuring uniform thickness of the polyurethane buffer layer, stable molding quality, and improving the bonding strength and structural integrity of the polyurethane buffer layer with the first rigid component and the second rigid component. At the same time, the process has strong controllability and good product consistency, making it suitable for mass production. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the polyurethane buffer layer structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the tooling installation structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a partial installation of the tooling in an embodiment of the present invention; Figure 4 This is a schematic diagram of the positioning and clamping steps in an embodiment of the present invention; Figure 5 This is a schematic diagram of the polyurethane casting steps in an embodiment of the present invention; Figure 6 This is a schematic diagram of the mold-closing steps in an embodiment of the present invention; Figure 7 This is a schematic diagram of the pressurization step in an embodiment of the present invention; Figure 8 This is a schematic diagram of the buffer hole distribution in an embodiment of the present invention; Figure 9 This is a schematic diagram of a polyurethane buffer layer tire that does not require inflation, provided in an embodiment of the present invention.

[0025] In the diagram, 110 is the tread; 120 is the tread buffer layer; 130 is the first rigid member; 140 is the polyurethane buffer layer; 141 is the buffer hole; and 150 is the second rigid member. 211. First positioning component; 212. Second positioning component; 2211. First forming pressure plate; 2212. First buffer hole bolt; 2221. Second forming pressure plate; 2222. Second buffer hole bolt; 231. First set screw; 232. Second set screw; 241. Connecting rod; 242. Compression spring. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] This invention provides a polyurethane buffer layer structure, a manufacturing process, and a tire incorporating the structure. The polyurethane buffer layer structure not only effectively isolates the tire tread from the axle but also fully absorbs the impact loads from the road surface acting on the pneumatic tire, improving cushioning and shock absorption, and significantly enhancing vehicle ride comfort. Furthermore, during vehicle operation, the polyurethane buffer layer structure can achieve overall load-bearing capacity in the radial, lateral, and longitudinal directions, improving load-bearing performance, effectively avoiding localized stress concentration, and significantly reducing the risk of damage caused by excessive localized stress.

[0028] This invention provides a polyurethane buffer layer structure that not only provides cushioning and shock absorption for pneumatic tires, offering strong support and improving their load-bearing capacity, but also reduces energy loss, thereby enhancing vehicle high-speed performance and driving range. (Reference) Figure 1 As shown, the polyurethane buffer layer structure includes a first rigid member 130, a second rigid member 150, and a polyurethane buffer layer 140 disposed between the first rigid member 130 and the second rigid member 150. The outer side of the polyurethane buffer layer 140 is bonded to the inner side of the first rigid member 130, and the inner side of the polyurethane buffer layer 140 is bonded to the outer side of the second rigid member 150. The inner and outer sides of the polyurethane buffer layer 140 are respectively bonded to the second rigid member 150 and the first rigid member 130 for fixation, thereby fixing the polyurethane buffer layer 140 to the second rigid member 150. The first rigid member 130 forms an integrated structure, allowing for uniform load distribution and coordinated bearing under stress. When the pneumatic tire bears external loads, the polyurethane buffer layer 140 simultaneously bears the combined effects of pressure, tension, and torque, resulting in a more uniform and rational stress distribution, improving the tire's shock absorption function and comfort performance. When the vehicle travels at speeds exceeding 100 km / h, the polyurethane buffer layer 140 bears stress as a whole, with heat evenly distributed and easily dissipated through the rigid ring, thus enhancing the high-speed performance of the pneumatic tire. Preferably, both the first rigid member 130 and the second rigid member 150 are made of metal materials such as aluminum alloy or magnesium alloy. The hardness of the polyurethane buffer layer 140 should be controlled to be less than 75 Shore hardness to avoid delamination later due to excessive hardness.

[0029] refer to Figure 1As shown, the polyurethane buffer layer 140 is provided with buffer holes 141, which can be one or more layers. The buffer hole 141 structure effectively improves the stress distribution of the polyurethane buffer layer 140, enhances its elastic deformation and rapid recovery performance, thereby improving the overall cushioning and shock absorption performance and driving comfort of the tire. The buffer holes 141 can adopt different sizes or different forms of structure, and are preferably circular holes. According to vehicle speed requirements, the structure of the buffer holes 141 can be adjusted to achieve the adjustment of the sinking amount, so that the airless tire can achieve a suitable ground contact mark and pressure to meet the vehicle's traction and braking performance. Adjusting the structure of the buffer holes 141 includes adjusting the diameter of the buffer holes 141, the distance between the buffer holes 141, and the number of layers of buffer holes 141. Because the polyurethane buffer layer 140 is subjected to overall stress, even with larger buffer holes 141, this structure can still improve the cushioning and shock absorption effect of the airless tire and provide strong support performance, thereby improving the load-bearing capacity of the airless tire.

[0030] The fabrication process of the polyurethane buffer layer structure in this embodiment of the invention includes the following steps: Pre-treatment steps: Clean the inner surface of the first rigid member 130 and the outer surface of the second rigid member 150 with alcohol or special cleaning agent. After drying, apply an adhesive that is compatible with polyurethane evenly to the bonding surface to achieve precise positioning of the first rigid member 130 and the second rigid member 150. Positioning and clamping steps: Refer to Figure 4 As shown, the first rigid member 130 is clamped and fixed to the first forming plate 2211 by the first positioning component 211, and the second rigid member 150 is clamped and fixed to the first forming plate 2211 by the second positioning component 212. Check and confirm that the installation is in place and there is no misalignment, and place the first forming plate 2211 at the bottom. Pre-gap setting step: A positioning auxiliary component is set between the first molding platen 2211 and the first positioning component 211 to form a pre-gap, so as to avoid overflow during the pouring process and ensure that the polyurethane material is fully filled; Pouring steps: Refer to Figure 5 As shown, polyurethane is poured into the gap formed between the first rigid member 130 and the second rigid member 150. The liquid level of the polyurethane is at least flush with the upper edge of the first rigid member 130 near the second molding plate 2221. The pouring method can be pouring with a pouring machine or pouring by manual mixing. The pouring time is less than 10 minutes and vulcanization is carried out quickly after pouring to avoid affecting the quality of the polyurethane buffer layer 140. The specific pouring method can be reasonably adjusted according to the requirements of different applications of pneumatic tires. Mold closing steps: Refer to Figure 6As shown, a second forming plate 2221 is assembled, and a positioning auxiliary component is provided between the second forming plate 2221 and the positioning component to form a pre-gap; Pressurization steps: Refer to Figure 7 As shown, a pressurizing assembly is installed, which connects the first forming plate 2211 and the second forming plate 2221. Vulcanization molding steps: Check that there is no misalignment during installation, remove the positioning auxiliary parts to release the pre-gap, place the assembled tooling in the vulcanization box, and vulcanize the tooling as a whole under the conditions of vulcanization temperature of 115-125℃ and vulcanization time of 24h to obtain a polyurethane buffer layer structure.

[0031] The above-described process steps of the present invention can precisely control the relative positions and overall molding dimensions between the first rigid component 130, the second rigid component 150 and the polyurethane buffer layer 140, so that the polyurethane buffer layer 140 has a uniform thickness and stable molding quality, significantly improving the bonding strength and structural integrity between the polyurethane buffer layer 140 and the inner first rigid component 130; by controlling the process parameters, polyurethane buffer layers 140 with different hardness requirements can be obtained; and it can also meet the needs of mass industrial production.

[0032] The preparation process of the polyurethane buffer layer structure in this embodiment of the invention is achieved by using a polyurethane buffer layer 140 tooling. This tooling can provide a stable and continuous clamping force during the curing and molding of the polyurethane material, so that the polyurethane material is fully bonded to the outer surface of the second rigid member 150 and the inner surface of the first rigid member 130, effectively expelling air bubbles generated during the casting and curing process, and improving the bonding strength between the polyurethane and the inner first rigid member 130.

[0033] refer to Figure 2 , 3As shown, the polyurethane buffer layer 140 tooling includes multiple tooling units with identical structures. Each tooling unit includes two molding components, a positioning component, a positioning auxiliary component, and two pressurizing components. The molding components are used for side molding and buffer hole molding of the polyurethane buffer layer 140. Each molding component includes a molding plate and buffer hole bolts disposed on the molding plate. The buffer hole bolts pass through the center of the corresponding molding plate and extend, and the extension directions of the buffer hole bolts of the two molding components are opposite. Preferably, the molding components include a first molding component and a second molding component. The first molding component is disposed at the bottom of the first rigid member 130 and the second rigid member 150. The first molding component includes a first molding plate 2211 and a first buffer hole bolt 2212 detachably disposed on the first molding plate 2211. The first buffer hole bolt 2212 passes through the first molding plate 2211. The first molding plate 2211 and the second molding plate 2221 are used to form the side shape of the polyurethane buffer layer 140. Under the action of the pressurizing component, continuous pressure is applied to the polyurethane material to expel the gas in the polyurethane material and ensure that the polyurethane material is tightly bonded to the second rigid member 150 and the first rigid member 130. The second buffer hole bolt 2222 matches the first buffer hole bolt 2212 to form the shape of the buffer hole 141.

[0034] The positioning component is connected to the molding component. The positioning component is used to clamp and fix the positions of the first rigid member 130 and the second rigid member 150. The positioning component includes a first positioning component 211 for clamping and fixing the first rigid member 130 and a second positioning component 212 for clamping the second rigid member 150. The first positioning component 211 and the second positioning component 212 are preferably fixing plates.

[0035] A positioning auxiliary component is disposed between the forming pressure plate and the positioning assembly. The positioning auxiliary component is used to form a pre-gap between the forming pressure plate and the corresponding positioning assembly. The pre-gap is removed and released before the vulcanization step so that the pressure assembly can provide continuous pressure, allowing the forming pressure plate to contact the adjacent positioning assembly after vulcanization. The positioning auxiliary component includes a first set screw 231 disposed on the first forming pressure plate 2211 and a second set screw 232 disposed on the second forming pressure plate 2221.

[0036] Each pressurizing assembly connects to the first molding platen 2211 and the second molding platen 2221. The pressurizing assembly is used to provide continuous pressure to the polyurethane material after mold closing. The pressurizing assembly includes two connecting rods 241, which are respectively disposed on the outside of the first rigid member 130 and the outside of the second rigid member 150. The two ends of each connecting rod 241 pass through the pre-set through holes on the first molding platen 2211 and the second molding platen 2221 and extend outward. Four compression springs 242 are respectively sleeved on the outwardly extending ends of each connecting rod 241, and the compression springs 242 are located on the outside of the first molding platen 2211 and the second molding platen 2221, and are used to apply a clamping force to the first molding platen 2211 and the second molding platen 2221.

[0037] refer to Figure 9 As shown in the figure, this embodiment of the invention also provides a pneumatic tire, including the polyurethane buffer layer structure. The pneumatic tire also includes a tread with a pattern to provide traction, braking, and wear resistance. The tread is made of rubber to ensure high-speed performance. A tread buffer layer 120 is disposed below the tread and outside the first rigid member 130. The tread buffer layer 120 is also made of rubber. Depending on the vehicle's usage scenario, the tread buffer layer 120 can be configured as one or more layers to improve ride comfort. This polyurethane buffer layer structure can replace traditional polyurethane buffer layers in vehicle tires, and the resulting pneumatic tire can be widely used in unmanned logistics vehicles, light trucks, military vehicles, and other fields.

[0038] To more clearly and in detail introduce the polyurethane buffer layer structure, manufacturing process, and airless tire containing the structure provided in the embodiments of the present invention, the following description will be based on specific embodiments.

[0039] Example 1 The polyurethane formulation used in this embodiment is shown in Table 1. The prepolymer serves to balance the reactivity of the polyurethane and improve processing convenience; the polyol plays a role in performance regulation; the polyol chain extender determines the molecular weight and density of the polyurethane and regulates its mechanical properties; and the catalyst promotes the growth of the polyurethane molecular chain. Specifically, the prepolymer is 3W8613T; the polyol is F2807; the polyol chain extender is KC332; and the catalyst is BL01. The polyurethane formulation is determined according to different market demands. Taking a Shore hardness of 70° as an example, the specific dosage and process requirements of the polyurethane formulation are shown in Table 1.

[0040] Table 1. Summary of Polyurethane Formulation Dosage and Process Requirements

[0041] The fabrication process of the polyurethane buffer layer structure in this embodiment includes the following steps: Pre-treatment steps: After drying the inner surface of the first rigid component 130 and the outer surface of the second rigid component 150 with alcohol, apply an adhesive that is compatible with polyurethane evenly to the bonding surface to achieve precise positioning of the first rigid component 130 and the second rigid component 150. Positioning and clamping steps: clamp and fix the first rigid member 130 to the first forming plate 2211 through the first positioning component 211, clamp and fix the second rigid member 150 to the first forming plate 2211 through the second positioning component 212, check and confirm that the installation is in place and there is no misalignment, and place the first forming plate 2211 at the bottom. Pre-gap setting step: A first set screw 231 is set between the first forming pressure plate 2211 and the first positioning component 211 to form a pre-gap; Casting steps: Using the polyurethane formula in Table 1, add catalyst BL01 to the tank of polyol F2807 and maintain it at 80°C for 14 hours. Then, use a casting machine to cast polyurethane into the gap formed between the first rigid component 130 and the second rigid component 150. Before casting, the equipment should be calibrated to ensure that each polyurethane material is quantitative and mixed evenly. The liquid level of polyurethane should be at least level with the upper edge of the first rigid component 130 near the second molding plate 2221. After casting, if the equipment is not used for a long time, the 3W8613T prepolymer tank should be cleaned with dioctyl phthalate (DOP) and sealed. The pipelines and nozzles should be cleaned with a special cleaning agent to avoid blockage. Mold closing steps: Assemble the second forming plate 2221, and set the second ejector screw 232 between the second forming plate 2221 and the positioning component to form a pre-gap; Pressurization step: Install connecting rod 241 and compression spring 242 so that connecting rod 241 connects the first forming pressure plate 2211 and the second forming pressure plate 2221; Vulcanization molding steps: Check that the installation is not misaligned, remove the first set screw 231 and the second set screw 232 to release the pre-gap, place the assembled tooling in the vulcanization box, and vulcanize the tooling as a whole under the conditions of vulcanization temperature of 120℃ and vulcanization time of 24h. It should be noted that after vulcanization, the polyurethane should be kept away from cooling too quickly to avoid poor adhesion caused by shrinkage of the polyurethane material. The temperature should be gradually reduced by holding at 80℃ for 5 minutes, 60℃ for 5 minutes, and 40℃ for 5 minutes until it is reduced to room temperature. Then remove the tooling to obtain the polyurethane buffer layer structure.

[0042] Performance testing The polyurethane buffer layer structure obtained in Example 1 was bonded to the tread buffer layer and the tread, and vacuum vulcanized to prepare an airless tire. The obtained airless tire was subjected to out-of-roundness test, pressure blanket test, stiffness test, rolling resistance coefficient test, indoor noise test and actual vehicle NVH test.

[0043] (1) Out-of-roundness To ensure that the out-of-roundness of the pneumatic tire is controlled within 1.2mm, the out-of-roundness of the pneumatic tire was measured at the positions of the five tread blocks divided by the four longitudinal tread main grooves. The test data are shown in Table 2. As can be seen from Table 2, the test results meet the product design goals.

[0044] Table 2. Out-of-roundness 3D scanning test data

[0045] (2) Pressure blanket test To ensure the braking and traction performance of the pneumatic tires, pressure blanket tests were conducted at five points along the circumference, with a load of 500 kg applied. The test data are shown in Table 3. As can be seen from Table 3, the test results meet the product design objectives.

[0046] Table 3 Pressure Blanket Test Data

[0047] (3) Stiffness test To ensure the comfort, handling, and safety performance of the pneumatic tire, stiffness tests were conducted at five points along the circumference, with a load of 500 kg applied. The test data are shown in Table 4. As can be seen from Table 4, the test results meet the product design objectives.

[0048] Table 4 Stiffness Test Data

[0049] (4) Rolling resistance coefficient test To ensure the energy-saving performance of the pneumatic tires, rolling resistance coefficients were tested using a rolling resistance testing machine at two common loads (400kg and 500kg) and three common speeds (40km / h, 60km / h and 80km / h). The test results are shown in Table 5. As can be seen from Table 5, the test results meet the product design objectives.

[0050] Table 5 Rolling resistance coefficient test data

[0051] (5) Indoor noise test To ensure the noise performance of the pneumatic tires, noise tests were conducted using a semi-anechoic chamber testing machine with two common loads (400kg and 500kg) and three common speeds (40km / h, 60km / h and 80km / h). The test results are shown in Table 6. As can be seen from Table 6, the test results meet the product design objectives.

[0052] Table 6 Indoor Noise Test Data

[0053] (6) Actual vehicle NVH test Using a Borgward BX80 with front-wheel drive and original pneumatic tires of 235 / 60R18, the vehicle was tested on an urban asphalt road (20~5000Hz) to verify its NVH performance at various speeds (40km / h, 60km / h, 80km / h).

[0054] Table 7 shows a comparison of the NVH test results (RMS values) of pneumatic tires and inflatable tires on actual vehicles. As can be seen from Table 7, the NVH performance of pneumatic tires and inflatable tires is basically the same.

[0055] Table 7. Actual Vehicle NVH Test Data

[0056] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, alterations, evolutions, or improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope of the present invention.

Claims

1. A polyurethane buffer layer structure, characterized in that, It includes a first rigid member, a second rigid member, and a polyurethane buffer layer. The polyurethane buffer layer is bonded between the first rigid member and the second rigid member by vulcanization. The polyurethane buffer layer has at least one layer of buffer holes.

2. The preparation process of the polyurethane buffer layer structure according to claim 1, characterized in that, Includes the following steps: Positioning and clamping steps: The first rigid component and the second rigid component are clamped and fixed to the first forming pressure plate by the positioning assembly; Pre-gap setting step: A positioning auxiliary component is set between the first forming pressure plate and the positioning component to form a pre-gap; Casting steps: Cast polyurethane into the gap formed between the first rigid member and the second rigid member; Mold closing steps: Assemble the second forming plate and set a positioning auxiliary component between the second forming plate and the positioning component to form a pre-gap; Pressurization step: Install the pressurization assembly, and connect the pressurization assembly to the first forming plate and the second forming plate; Vulcanization molding step: Release the pre-gap and vulcanize the tooling as a whole to obtain the polyurethane buffer layer structure.

3. The preparation process of the polyurethane buffer layer structure according to claim 2, characterized in that, The positioning and clamping step includes a pretreatment step: cleaning the bonding surfaces of the first rigid component and the second rigid component and applying adhesive.

4. The preparation process of the polyurethane buffer layer structure according to claim 2, characterized in that, During the casting step, the polyurethane liquid level is at least flush with the upper edge of the first rigid member near the second molding plate.

5. The preparation process of the polyurethane buffer layer structure according to claim 2, characterized in that, In the vulcanization molding step, the pre-gap is released by removing the positioning auxiliary components; the vulcanization temperature is 115-125℃, and the vulcanization time is 24h.

6. The preparation process of the polyurethane buffer layer structure according to claim 2, characterized in that, The process employs a polyurethane buffer layer fixture, which comprises multiple identical fixture units, each fixture unit including... Two molding components are provided, wherein the molding components are used for side molding of the polyurethane buffer layer and molding of the buffer holes; A positioning component is connected to the molding component, and the positioning component is used to clamp and fix the positions of the first rigid component and the second rigid component; A positioning auxiliary component is disposed between the forming platen and the positioning assembly, and the positioning auxiliary component is used to form a pre-gap between the forming platen and the positioning assembly; Two sets of pressurizing components, each of which is connected to two sets of molding components within the same tooling unit, are used for mold closing and to provide continuous pressure to the polyurethane material.

7. The preparation process of the polyurethane buffer layer structure according to claim 6, characterized in that, Each group of molding components includes Forming pressure plate; A buffer hole bolt passes through the center of the corresponding forming plate and extends, and the extension directions of the buffer hole bolts of the two forming components in each tooling unit are opposite.

8. The preparation process of the polyurethane buffer layer structure according to claim 7, characterized in that, Each of the pressurization components includes Two connecting rods, each with its two ends passing through pre-set through holes on two opposing forming plates within the same tooling unit and extending outwards; Four compression springs are respectively fitted onto the outward-extending ends of each connecting rod, and the compression springs are located on the outside of the forming pressure plate.

9. A tire, characterized in that, Includes the polyurethane buffer layer structure as described in claim 1.

10. The tire according to claim 9, characterized in that, The tire also includes a tread and a tread buffer layer arranged sequentially from the outside to the inside. The tread buffer layer is disposed on the outside of the first rigid member, and the tread buffer layer is at least one layer.

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