Airless solid tyre

Abstract

The present subject matter relates to an airless solid tyre 200, 300. The airless solid tyre 200, 300 includes an elastic body 202, EB having a ring-shaped structure defined by an outer surface 204, S3, an inner surface 206, S4 opposite the outer surface 204, S3, a first sidewall 208, S1 extending between the outer surface 204, S3 and the inner surface 206, S4 at a first side of the elastic body 202, EB, and a second sidewall 210, S2 extending between the outer surface 204, S3 and the inner surface 206, S4 at a second side, opposite the first side, of the elastic body 202, EB. The elastic body 202, EB includes at least one cavity 212, 302 fully enclosed within the ring-shaped structure and extending along a circumferential length of the elastic body 202, EB.

Description

AIRLESS SOLID TYREFIELD OF THE INVENTION

[0001] The present subject matter generally relates to the field of tyres, and more specifically, to airless solid tyres and methods of manufacturing of the airless solid tyres.BACKGROUND

[0002] Vehicles, ranging from two-wheeled vehicles to larger vehicles, are typically equipped with tyres. The tyres are typically manufactured using basic raw materials, for example, rubber, carbon black, hardening chemicals, etc. The tyres are typically designed, using the raw materials, in a ring-shape to surround a rim of a wheel of a vehicle. The tyres provide traction to the vehicle and allow the vehicle to move smoothly withstanding the rigors of daily use.BRIEF DESCRIPTION OF DRAWINGS

[0003] The features, aspects, and advantages of the subject matter will be better understood with regard to the following description and accompanying figures.

[0004] FIG. 1 illustrates a cross-sectional view of a conventional solid tyre;

[0005] FIG. 2 illustrates a cross-sectional view of an airless solid tyre, in accordance with an implementation of the present subject matter;

[0006] FIG. 3 illustrates a cross-sectional view of an airless solid tyre, in accordance with another implementation of the present subject matter; and

[0007] FIG. 4 illustrates a schematic of a mold assembly to manufacture an airless solid tyre having an outer diameter of 16 inches and a tyre section width of 2.5 inches, in accordance with another implementation of the present subject matter.DETAILED DESCRIPTION

[0008] Traditionally, either pneumatic or solid tyre have been used in vehicles, such as micro -mobility scooters, scooters, motorcycles, three-wheelers, golf carts, lawn mowers, four wheeled vehicles, and other larger vehicles. Pneumatic tyres are filled with air but are prone to punctures. Solid tyres, on the other hand, are filled with rubber or similar compounds and are puncture-proof.

[0009] However, both types of tyres have their own set of advantages and disadvantages. Pneumatic tyres, for instance, offer a comfortable ride due to their ability to absorb shock from the road. However, the pneumatic tyres require regular maintenance and are susceptible to punctures, which can lead to downtime and potential safety risks. Such regular maintenance may also disturb the alignment of the tyre that was set by factory on a wheel’s rim of a vehicle, thereby reducing the life of the tyre. Solid tyres, being puncture -proof require less maintenance. However, the solid tyres may not always provide the same level of comfort as the pneumatic tyres since the solid tyres lack a cushioning effect. Furthermore, the solid tyres are not suitable for high-speed applications. This is because the solid tyres can cause heat build-up due to high rolling resistance, leading to tyre failure.

[0010] The present subject matter describes an airless solid tyre and a method to manufacture the airless solid tyre. Such an airless solid tyre combines the benefits of both pneumatic and solid tyres while mitigating their respective drawbacks. This is achieved with the presence of one or more cavities within the airless solid tyre, which are fully enclosed and not accessible from the outside. In an example implementation, the airless solid tyre includes an elastic body having a ring-shaped structure. The elastic body refers to the main structure of the airless solid tyre, which is made from a flexible and resilient material, typically a type of rubber or synthetic compound. This material allows the airless solid tyre to deform under the load and return to its original shape when the load is removed, providing the necessary cushioning effect.

[0011] The ring-shaped structure is defined by an outer surface and an inner surface opposite the outer surface. The outer surface is the part of the airless solidtyre that comes into contact with the road. In an example, the outer surface may feature a tread pattern to provide traction. The inner surface is the part of the airless solid tyre that faces the wheel rim and is typically smooth to ensure a proper fit. The ring-shaped structure is further defined by a first sidewall extending between the outer surface and the inner surface at a first side of the elastic body, and a second sidewall extending between the outer surface and the inner surface at a second side, opposite the first side of the elastic body. The first sidewall is the lateral surface of the airless solid tyre on one side, extending from the outer surface to the inner surface. The second sidewall is the lateral surface on the opposite side of the airless solid tyre.

[0012] The elastic body includes at least one cavity fully enclosed within the ring-shaped structure and extending along a circumferential length of the elastic body. The cavity is a hollow portion along the circumference of the airless solid tyre. The cavity facilitates providing a cushioning effect to a rider or a driver of the vehicle, enhancing the comfort of the rider or the driver while riding the vehicle. Further, since the cavity is not fillable with air it ensures that the airless solid tyre is puncture-proof, thereby reducing the risk of unexpected breakdowns and the associated maintenance requirements. The cavities within the tyre structure serve a crucial function. They act as shock absorbers, compressing and expanding as the tyre encounters bumps and irregularities in the road surface. This action mimics the cushioning effect of air in a pneumatic tyre, but without the risk of punctures. As a result, the airless solid tyre reduces or eliminates the probability of disturbing factory set tyre alignment throughout the life of tyre, thereby increasing the overall life of the tyre.

[0013] In one example implementation of the present subject matter, the airless solid tyre may include a single cavity within the ring-shaped structure, particularly a single large hollow portion within the solid portion of the tyre.

[0014] In another example implementation of the present subject matter, the airless solid tyre may include multiple cavities within the solid portion of the tyre. In both implementations, the cavity may extend throughout the inner circumferenceof the tyre such that the cavities are neither visible from the outer surface nor from the inner surface of the airless solid tyre. For example, in a micro -mobility scooter application, the airless solid tyre might feature multiple small cavities arranged in a honeycomb pattern within the tyre structure. These cavities would compress slightly when the scooter encounters a small bump or pothole, absorbing the shock and providing a smoother ride for the user. In contrast, for a larger vehicle like a golf cart, the airless solid tyre might incorporate a single, larger cavity running the circumference of the tyre. This design would provide the necessary cushioning for a heavier vehicle while maintaining the structural integrity required for supporting the vehicle's weight.

[0015] In one implementation, the size and number of the cavities may vary depending on various factors, such as a size of the tyre and a type of the vehicle for which the tyre is to be used. The airless solid tyre can thus be designed for a wide array of vehicles, ranging from micro mobility scooters to larger vehicles.

[0016] The cavity is configured to provide compressibility and shock absorption to the airless solid tyre during use. The airless solid tyre thus facilitates in addressing common drawbacks associated with the conventional pneumatic and solid tyres. The airless solid tyre, with its innovative design, offers a solution that combines the advantages of both pneumatic and solid tyres, providing a comfortable ride that requires less maintenance. The airless solid tyre's design significantly reduces the likelihood of surprise down-times, improving overall vehicle reliability and reducing maintenance costs.

[0017] The airless solid tyres are puncture-proof such that the airless solid tyre cannot be deflated or rendered inoperable by sharp objects penetrating its surface. Unlike pneumatic tyres, there is no air pressure to lose, and unlike traditional solid tyres, the presence of cavities allows for some degree of compression and shock absorption. The concept of "rolling resistance" is important when considering tyre performance, especially for solid tyres. It refers to the force resisting the motion when a tyre rolls on a surface. Higher rolling resistance leads to increased fuel consumption and heat generation. The cavities in the airless solidtyre help reduce rolling resistance compared to traditional solid tyres, making them more suitable for higher-speed applications.

[0018] The present subject matter is further described with reference to FIG.1 to FIG. 4. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof. All examples recited herein are intended only to aid the reader in understanding the principles of the present subject matter, and such examples should not be construed as limitations.

[0019] FIG. 1 illustrates a cross-sectional view of a convention solid tyre 100. The convention solid tyre 100 may be a ring-shaped tyre. Further, the cross- sectional view may be viewed after cutting the convention solid tyre 100 along the diameter of the convention solid tyre 100. As illustrated in FIG. 1, the conventional solid tyre 100 is filled completely with rubber throughout the cross-sectional view of the conventional solid tyre 100.

[0020] FIG. 2 illustrates a cross-sectional view of an airless solid tyre 200, in accordance with an implementation of the present subject matter. In an example, the airless solid tyre 200 may be a ring-shaped tyre. Further, the cross-sectional view may be viewed after cutting the airless solid tyre 200 along the diameter of the airless solid tyre 200. As illustrated in FIG. 2, the airless solid tyre 200 includes an elastic body 202 having a ring-shaped structure. The elastic body 202 may be made of rubber. The ring-shaped structure is defined by an outer surface 204 and an inner surface 206 opposite the outer surface 204. The ring-shaped structure is further defined by a first sidewall 208 extending between the outer surface 204 and the inner surface 206 at a first side of the elastic body 202, and a second sidewall 210 extending between the outer surface 204 and the inner surface 206 at a second side, opposite the first side of the elastic body 202. The elastic body 202 includes at least one cavity 212 fully enclosed within the ring-shaped structure and extendingalong a circumferential length of the elastic body 202. The airless solid tyre 200 is designed to provide a cushioning effect similar to that of a pneumatic tyre, but without the need for air pressure. This is achieved through the strategic placement and design of the cavity 212 within the elastic body 202. The cavity 212 allows for controlled deformation of the tyre under load, providing shock absorption and improving ride comfort. The cavity 212 is configured to provide compressibility and shock absorption to the airless solid tyre 200 during use.

[0021] The cavity 212 is a hollow portion 202 within the airless solid tyre 200. The hollow portion is formed as a single large hollow portion within the solid portion of the airless solid tyre 200. The hollow portion may extend throughout the circumference of the airless solid tyre 200. In an example, the at least one cavity 212 is a single cavity within the ring-shaped structure. The single cavity may be referred to as 212. A first shortest distance 214 between the first sidewall 208 and a boundary of the single cavity 212 is 13+3 mm, a second shortest distance 216 between the second sidewall 210 and the boundary of the single cavity 212 is 13+3 mm, a third shortest distance 218 between the outer surface 204 and the boundary of the single cavity 212 is 13+3 mm, and a fourth shortest distance 220 between the inner surface and the boundary of the single cavity is 13+3 mm. The first shortest distance 214 is X+3 mm, where X is 13 mm. The second shortest distance 216 is X+3 mm, where X is 13 mm. The third shortest distance 218 is X+3 mm, where X is 13 mm. The fourth shortest distance 220 is X+3 mm, where X is 13 mm. The elastic body 202 has an outer diameter of 16 inches measured from the outer surface 204 and a tyre width of 2.5 inches measured between the first sidewall 208 and the second sidewall 210. In an example, a size of each of the cavity, a shape of each of the at least one cavity, and a number of the at least one cavity is customized based on one or more of dimensions of the elastic body, a vehicle type intended to use the airless solid tyre, and a desired cushioning effect associated with the airless solid tyre

[0022] In an example, when the airless solid tyre 200 is to be used in a twowheeled vehicle, such as a micro mobility scooter meant for a maximum speed ofaround 30 Km / hr, a weight of the airless solid tyre 200 may be, but is not limited to, 2.5 kg. In an example, the airless solid tyre 200 is to be used in a four-wheeled vehicle. In an example, the airless solid tyre 200 may be used for heavy duty vehicles.

[0023] In an example, the first shortest distance 214, the second shortest distance 216, the third shortest distance 218, and the fourth shortest distance 220 may have a value depending on one or more of type of vehicle, maximum speed of vehicle, and weight of the airless solid tyre. The first shortest distance 214, the second shortest distance 216, the third shortest distance 218, and the fourth shortest distance 220 may be referred to as the first gauge range, the second gauge range, the third gauge range, and the fourth gauge range , respectively. The first gauge range is defined as a shortest distance between a boundary of the cavity 212 and the first sidewall 208 of the airless solid tyre 200. The second gauge range may be defined as a shortest distance between a boundary of the cavity and a tread of the airless solid tyre 200. The third gauge range may be defined as a shortest distance between a boundary of the cavity 212 and a second sidewall 210 of the airless solid tyre 200. The fourth gauge range may be defined as a shortest distance between a boundary of the cavity and an inner wall 206 of the airless solid tyre 200. In an example, the airless solid tyre 200 has a weight of 2.5 kg. In an example, the airless solid tyre 200 has a weight depending on the size of the vehicle in which the airless solid tyre 200 is used.

[0024] The customization of the airless solid tyre 200 can also take into account specific performance requirements. For high-speed applications, the cavity shape may be optimized to reduce heat buildup and maintain stability. For off-road use, the cavity design may prioritize impact resistance and flexibility. For urban use, the cavity may be tuned to provide a balance between comfort and low rolling resistance. The material composition of the elastic body 202 can be adjusted to complement the cavity design. Softer compounds may be used in conjunction with smaller cavities for improved comfort. Harder compounds may be paired with larger cavities for increased durability and load-bearing capacity.

[0025] In an example, the airless solid tyre 200 design also offers potential for integrating sensors or other smart technologies within the structure, utilizing the cavity space for housing electronic components while maintaining the tyre's primary functional characteristics.

[0026] FIG. 3 illustrates a cross-sectional view of an airless solid tyre 300, in accordance with an implementation of the present subject matter. In an example, the airless solid tyre 300 may be a ring-shaped tyre and includes an elastic body EB similar to the elastic body of FIG.2. Further, the cross-sectional view may be viewed after cutting the airless solid tyre 300 along the diameter of the airless solid tyre 300. As illustrated in FIG. 3, the airless solid tyre 300 is filled with rubber, but has a plurality of cavities 302 within the airless solid tyre 300. In FIG. 3, four cavities 302a, 302b, 302c, and 302d have been illustrated, hereinafter may be interchangeably referred to as 302. However, the number of cavities within the airless solid tyre 300 may be greater than or equal to 2 according to a desired application where the airless solid tyre 300 is to be utilized. Further, the shape and size of the cavities 302 may vary depending on various factors, such as a size of the tyre and a type of the vehicle for which the tyre is to be used. The cavities 302 may extend throughout the circumference of the airless solid tyre 300. The cavity 302 is configured to provide compressibility and shock absorption to the airless solid tyre 300 during use.

[0027] In an example, when the airless solid tyre 300 is to be used in a twowheeled vehicle, such as a micro mobility scooter meant for a maximum speed of around 30 Km / hr, a weight of the airless solid tyre 300 may be, but is not limited to, 2.5 kg. In such an airless solid tyre 300, a first gauge range 304, a second gauge range 306, a third gauge range 308, and a fourth gauge range 310 may be around 7+2 mm. In an example, the first gauge range 304, the second gauge range 306, the third gauge range 308, and the fourth gauge range 310 may have a value depending on one or more of type of vehicle, maximum speed of vehicle, and weight of the airless solid tyre. The first gauge range 304 may be defined as a shortest distance between a boundary of one of the plurality of cavities 302 and a first sidewall of theairless solid tyre 300. The second gauge range 306 may be defined as a shortest distance between a boundary of one of the plurality of cavities 302 and a tread of the airless solid tyre 300. The third gauge range 308 may be defined as a shortest distance between a boundary of one of the plurality of cavities 302 and a second sidewall of the airless solid tyre 300. The fourth gauge range 310 may be defined as a shortest distance between a boundary of one of the plurality of cavities 302 and an inner wall of the airless solid tyre 300.

[0028] In an example, the at least one cavity is a set of a first cavity 302a closest to the first sidewall SI, a second cavity 302c closest to the second sidewall S2, a third cavity 302b closest to the outer surface S3, and a fourth cavity 302d closest to the inner surface among the closest to the first sidewall S 1 among the first sidewall SI, the second sidewall S2, the outer surface S3, and the inner surface S4. In an example, a first shortest distance between the first sidewall and a boundary of the first cavity is 7+2 mm, a second shortest distance between the second sidewall and a boundary of the second cavity is 7+2 mm, a third shortest distance between the outer surface and a boundary of the third cavity is 7+2 mm, and a fourth shortest distance between the inner surface and a boundary of the fourth cavity is 7+2 mm.

[0029] In an example, the airless solid tyre 200 having a single hollow portion 202 and the airless solid tyre 300 may be manufactured using a similar manufacturing process. The difference in the manufacturing process for the airless solid tyre 200 and the airless solid tyre 300 may lie in an extrusion process where the compound using which the tyre is formed is extruded to form the desired shape and size of the hollow portions 212, 302.

[0030] The manufacturing process of the airless solid tyre 200, 300 may involve several steps. Initially, raw materials such as rubber, carbon black, required chemicals, and oils may be mixed in a set proportion and a preset sequence at preset conditions to form a rubber compound. The rubber compound is the primary material used to create the tyre. In an example, it’s a mixture of raw rubber (which can be natural or synthetic), carbon black (a reinforcing agent), and various chemicals and oils. The specific composition of this compound is crucial as itdetermines the final properties of the tyre, such as its durability, flexibility, and resistance to wear and tear.

[0031] The set proportion may be determined based on desired properties of the airless solid tyre 200, 300. The rubber compound may then be cooled and aged to form a mould. In an example, the airless solid tyre 200 having a single hollow portion 202 and the airless solid tyre 300 having a plurality of hollow portions 302 may be produced using a same type of the mould. The rubber compound, after ageing, may be extruded at an extruder to form a desired shape and dimension and a desired number of hollow portions 212, 302. The extruded material, also referred to as green slugs, may then be stored after proper cooling for ageing. After proper ageing, the extruded material is joined / spliced and then vulcanized. To keep the hollow portion intact during curing, steam / air supply to extrudate is provided. Extrusion is a manufacturing process where the rubber compound is forced through a die to create a continuous shape. In tyre manufacturing, extrusion is used to form the basic structure of the tyre, including the creation of hollow portions. The die used in extrusion can be adjusted to create different shapes and sizes of hollow portions, allowing for the production of both single-cavity (tyre 200) and multicavity (tyre 300) designs.

[0032] In an example, the manufacturing process for airless solid tyres, such as the airless solid tyre 200 and 300, involves several precise and coordinated steps. The primary focus of this process is to create a durable rubber tyre with integrated hollow portions that help maintain flexibility, shock absorption, and structural integrity. The first step involves preparing the rubber compound, which forms the base material for the tyre. The compound is made by mixing the following raw materials in specific proportions and sequences. Rubber is the main material that forms the tyre. Various types of rubber may be used, such as natural rubber or synthetic rubber, depending on the desired properties of the final tyre. Carbon black is added to enhance the strength and durability of the rubber. It helps to reinforce the rubber compound and provides better wear resistance. Various chemicals and oils are added to the compound to improve the processing characteristics, increaseflexibility, and enhance other performance attributes, such as heat resistance, longevity, or weather resistance. The exact proportions and types of chemicals and oils used are determined based on the desired properties of the tyre, including hardness, elasticity, and wear resistance. Once the raw materials are mixed, the rubber compound is subjected to controlled conditions (temperature, pressure, and time) to ensure proper consistency and uniformity. The rubber compound is then cooled and aged to ensure that the materials interact properly, allowing the rubber to become more stable and easier to process. After cooling and aging, the rubber compound is placed in a mould. In this case, a single type of mould is used to create both the airless solid tyre 200 (with a single hollow portion) and the airless solid tyre 300 (with multiple hollow portions). The molds are specifically designed to form these hollow portions during the next stages of processing. The cooled and aged rubber compound is then sent to an extruder, which shapes it into the desired form. The extruder forces the material through a die to produce long, continuous shapes, known as green slugs. These green slugs have the approximate dimensions and shape of the tyre but are still uncured and relatively soft. In an example, the green slugs are the uncured, extruded pieces of rubber that form the basic shape of the tyre. They are called "green" because they haven't yet undergone the vulcanization process. These slugs are the raw form of the tyre that will later be shaped and cured into the final product.

[0033] During extrusion, the number and shape of the hollow portions (202 or 302) are created by adjusting the die design and extrusion process. For the airless solid tyre 200, there is a single hollow portion, while for the airless solid tyre 300, there are multiple hollow portions. These hollow portions are critical to the tyre’s performance as they allow for deformation and flexibility while also maintaining the overall structural integrity of the tyre. After extrusion, the green slugs are cooled down to stabilize them and prevent any deformation. These extruded slugs are stored for further aging. The ageing process allows the rubber to continue curing and further stabilizes the material, making it more durable. Once the extruded green slugs are fully aged, they may need to be joined together (spliced) to form the final shape of the tyre. This is particularly important if the tyre requires continuous,seamless construction or if the hollow portions must be reinforced in certain areas. The splicing process typically involves aligning the edges of the green slugs and joining them together to form the complete structure. This step ensures that the tyre has the proper form before vulcanization. The tyre is then subjected to a process called vulcanization, where it is heated under pressure in a mould to cure the rubber. Vulcanization crosslinks the polymer chains within the rubber, making it stronger, more elastic, and heat-resistant. This process is essential for achieving the desired mechanical properties of the final tyre.

[0034] During vulcanization, the tyre takes its final shape and gains the required hardness, elasticity, and durability. The hollow portions created during the extrusion process must be preserved during vulcanization, as these hollow portions play a crucial role in the performance of the airless tyre. To ensure these hollow portions remain intact, steam or air supply is provided to the extrudate (green slugs) during the curing process. This air or steam pressure helps maintain the internal structure of the hollow portions, preventing them from collapsing or deforming under the heat and pressure of the vulcanization process. After vulcanization, the tyre is removed from the mould and cooled to room temperature. Once cooled, the tyre is inspected for defects, consistency, and adherence to quality standards. This includes checking the structure of the hollow portions to ensure they are properly formed and intact. The hollow portions are the cavities (212 in tyre 200, and 302a, 302b, 302c, 302d in tyre 300) intentionally created within the tyre structure. These hollow portions are crucial to the performance of airless tyres as they allow for deformation and flexibility, mimicking some of the characteristics of air-filled tyres while maintaining the benefits of a solid structure.The tyre is then ready for final use or additional processing, such as trimming, surface treatments, or adding finishing touches like treads or branding.

[0035] The manufacturing process described combines these elements to create a unique type of tyre that offers the benefits of both solid and pneumatic tyres. The careful control of compound composition, extrusion parameters, and vulcanization conditions allows for the production of tyres with specificperformance characteristics suited to different applications, from micro-mobility scooters to potentially larger vehicles.

[0036] FIG. 4 illustrates a schematic 400 of a mold assembly to manufacture an airless solid tyre having an outer diameter of 16 inches and a tyre section width of 2.5 inches, in accordance with another implementation of the present subject matter. The mold assembly can be adapted accordingly depending on the size of outer diameter and the tyre section width.

[0037] In an example, a method of manufacturing an airless solid tyre is described. The method of manufacturing an airless solid tyre involves several key steps, each contributing to the final product's quality and performance. The process begins with the careful selection and mixing of raw materials, followed by compound preparation, extrusion, splicing, and finally, vulcanization.

[0038] In the method, master raw materials are mixed in a pre-defined proportion and a pre-defined sequence to obtain a mixed compound and further the mixed compound may be aged for a pre-defined time period to obtain an aged mixed compound. Further, additional raw materials and the aged mixed compound may be mixed at preset conditions to form a mould and the mould may be extruded and spliced to obtain a green slug having a ring-shaped structure defined by an outer surface, an inner surface opposite the outer surface, a first sidewall extending between the outer surface and the inner surface at a first side of the elastic body, and a second sidewall extending between the outer surface and the inner surface at a second side, opposite the first side, of the elastic body. In an example, the green slug comprises at least one cavity fully enclosed within the ring-shaped structure and extending along a circumferential length of the elastic body. In an example, the master raw materials, including ribbed smoked sheets (RSS), styrene -butadiene rubber (SBR) 1502, reclaim rubber, carbon black N33O, devulcanized rubber crumb, Ultrasil VN 3 (a type of silica), zinc oxide, stearic acid, wax, anti-ozonants, antioxidants, and polyethylene glycol (PEG) 4000, are mixed in a predetermined proportion and sequence. This mixing is carried out in a specialized mixer equipped with two rotors featuring different wing configurations. The mixing process aimsto achieve a homogeneous compound with consistent properties throughout. After mixing, the compound is aged for a specified period, typically 8 hours for the master batch. This aging process is crucial for molecular stability, allowing the polymer chains to relax and align, which improves the overall properties of the final product. Following the aging process, additional raw materials such as soluble sulphur, prevulcanization inhibitors, and accelerators like TBBS (N-tert-butyl-2- benzothiazolesulfenamide) are incorporated into the aged compound under preset conditions. This step prepares the compound for the subsequent forming and vulcanization processes.

[0039] Further, a vulcanization process may be performed on the green slug to obtain the airless solid tyre. In an example, the raw materials include, but is not limited to, ribbed smoked sheets (RSS), styrene-butadiene rubber (SBR) 1502, Reclaim, Carbon Black N33O, devulcanized rubber crumb, Ultrasil VN 3, Zinc Oxide, Stearic Acid, Wax, an anti ozanant, an anti oxidant, and polyethylene glycol (PEG) 4000. In an example, the additional raw materials include, but is not limited to, Soluble Sulphur, Pre- Vulcanized inhibitor, and Accelerator TBBS. The final step in the manufacturing process is vulcanization, also known as curing. This process is carried out in two-piece tyre molds heated by top and bottom platens. The curing temperature is maintained at 138 ± 4 degrees Celsius, with a hydraulic pressure of 120-140 kg / cm2for mold closing. Steam may be dispensed inside the cavity to aid in the vulcanization process. The curing cycle, which involves carefully controlled time, temperature, and pressure parameters, is determined based on the rheological properties of the compound and the desired final properties of the tyre.

[0040] This comprehensive manufacturing process results in an airless solid tyre with improved wear and tear properties, suitable for various applications where traditional pneumatic tyres may not be ideal.

[0041] The raw materials may be mixed in a mixer (not shown) as per specified sequence. The purpose of mixing is to achieve homogeneous mixture of materials in order to get consistent optimum properties. Uniform distribution anddispersion are very important. Different ingredients have different dispersion characteristics so sequence of addition of materials are decided accordingly. In a mixer, there are 2 rotors (not shown) with different wings, a ram makes pressure & sharing takes place between the rotors, so the raw materials are mixed. To avoid excessive heat generation due to sharing, cooling water is being circulated in chambers (now shown) and rotors. At a specified temperature, mixed compound is dumped. Mixing cycle may depend on rotor speed, ram pressure and temperature. 8 hrs ageing required for master batch. The mixing compound may be dumped around 150-160 degrees, compound ageing is a must for molecular stability. Curatives are added at lower temperature to avoid scorchy / lump problem in process. Batch weight is decided based on mixer volume & specific gravity of compound. Further for the purpose of extrusion, it is to get required profile and dimensions. Extrusion of compounds may be done through an extruder (not shown). Specified die to be fixed to get shape of slug of particular size screw rotation per minute is set as per spec. The extruder is fed with rubber strip. The gauge and the width of the rubber strip is set as per spec. A desired shape of extrudate is achieved by using a die plate. Line speed of the extrudate is to be kept getting required dimension and weight. The slug cutting angle is to be kept 30 degrees for better splicing. Extrudate sectional perimeter, length, width & weight to be achieved as per spec. Slugs cooling is ensured and are to be booked in a leaf trolly for ageing. After specified aging, slugs can be used for warming up & splicing process.

[0042] In an example, slug warming is required for proper splicing. The splicing is done to join the ends of slug and to make a circular ring.

[0043] Further, curing may be performed. The curing is a process of vulcanization to improve wear and tear properties. For the curing, two-piece tyre molds (not shown) are being used. Molds are heated using top and bottom platen. Curing Temperature is 138 + / - 4 degree centigrade. Hydraulic pressure of mould closing: 120 -140 Kg / cm2. Inside the cavity, steam may be dispensed. For curing any tyre, 3 parameters are important i.e. time, temperature and pressure. Cure cycle is decided based on rheological properties and temperature.

[0044] The present invention provides an airless solid tyre that, on one hand, is puncture-proof and, on the other hand, provides a cushioning effect. As a result, the airless solid tyre can be used in a wide variety of vehicles for various transportation.

[0045] While this detailed description has disclosed certain specific embodiments for illustrative purposes, various modifications will be apparent to those skilled in the art, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Claims

We claim:

1. An airless solid tyre (200, 300) comprising: an elastic body (202, EB) having a ring-shaped structure defined by an outer surface (204, S3), an inner surface (206, S4) opposite the outer surface (204, S3), a first sidewall (208, SI) extending between the outer surface (204, S3) and the inner surface (206, S4) at a first side of the elastic body (202, EB), and a second sidewall (210, S2) extending between the outer surface (204, S3) and the inner surface (206, S4) at a second side, opposite the first side, of the elastic body (202, EB), wherein the elastic body (202, EB) comprises at least one cavity (212, 302) fully enclosed within the ring-shaped structure and extending along a circumferential length of the elastic body (202, EB), and wherein the at least one cavity (212, 302) is configured to provide compressibility and shock absorption to the airless solid tyre (200, 300) during use.

2. The airless solid tyre (200, 300) as claimed in claim 1, wherein a size of each of the at least one cavity (212, 302), a shape of each of the at least one cavity (212, 302), and a number of the at least one cavity (212, 302) is customized based on at least one of: dimensions of the elastic body (202, EB), a vehicle type intended to use the airless solid tyre (200, 300), and a desired cushioning effect associated with the airless solid tyre (200, 300).

3. The airless solid tyre (200, 300) as claimed in one of claims 1 and 2, wherein the elastic body (202, EB) has an outer diameter of 16 inches measured from the outer surface (204, S3) and a tyre width of 2.5 inches measured between the first sidewall (208, SI) and the second sidewall (210, S2).

4. The airless solid tyre (200, 300) as claimed in one of claims 1 to 3, wherein the airless solid tyre (200, 300) has a weight of 2.5 kg.

5. The airless solid tyre (200) as claimed in one of claims 1 to 4, wherein the at least one cavity (212) is a single cavity within the ring-shaped structure, wherein a first shortest distance (214) between the first sidewall (208) and a boundary of the single cavity is 13+3 mm, a second shortest distance (216) between the second sidewall(210) and the boundary of the single cavity is 13+3 mm, a third shortest distance (218) between the outer surface (204) and the boundary of the single cavity is 13+3 mm, and a fourth shortest distance (220) between the inner surface (206) and the boundary of the single cavity is 13+3 mm.

6. The airless solid tyre (300) as claimed in one of claims 1 to 4, wherein: the at least one cavity (302) is a set of a first cavity (302a) closest to the first sidewall (SI), a second cavity (302c) closest to the second sidewall (S2), a third cavity (302c) closest to the outer surface (S3), and a fourth cavity (302d) closest to the inner surface (S4) among the closest to the first sidewall (SI) among the first sidewall (S 1), the second sidewall (S2), the outer surface (S3), and the inner surface (S4); and a first shortest distance between the first sidewall (SI) and a boundary of the first cavity (302a) is 7+2 mm, a second shortest distance between the second sidewall (S2) and a boundary of the second cavity (302b) is 7+2 mm, a third shortest distance between the outer surface (S3) and a boundary of the third cavity (302c) is 7+2 mm, and a fourth shortest distance between the inner surface (S4) and a boundary of the fourth cavity (302d) is 7+2 mm.

7. A method of manufacturing an airless solid tyre (200, 300), the method comprising: mixing master raw materials in a pre-defined proportion and a pre-defined sequence to obtain a mixed compound; ageing the mixed compound for a pre-defined time period to obtain an aged mixed compound; mixing additional raw materials and the aged mixed compound at preset conditions to form a mould; extruding and splicing the mould to obtain a green slug having a ring-shaped structure defined by an outer surface (204, S3), an inner surface (206, S4) opposite the outer surface (204, S3), a first sidewall (208, SI) extending between the outer surface (204, S3) and the inner surface (206, S4) at a first side of the elastic body (202), and a second sidewall (210, S2) extending between the outer surface (204, S3) and the inner surface (206, S4) at a second side, opposite the first side, of theelastic body (202), wherein the green slug comprises at least one cavity (212, 302) fully enclosed within the ring-shaped structure and extending along a circumferential length of the elastic body (202); and performing a vulcanization process on the green slug to obtain the airless solid tyre (200, 300).

8. The method as claimed in claim 7, wherein the raw materials include ribbed smoked sheets (RSS), styrene-butadiene rubber (SBR) 1502, Reclaim, Carbon Black N33O, devulcanized rubber crumb, Ultrasil VN 3, Zinc Oxide, Stearic Acid, Wax, an anti ozanant, an anti oxidant, and polyethylene glycol (PEG) 4000.

9. The method as claimed in one of claims 7 and 8, wherein the additional raw materials include Soluble Sulphur, Pre- Vulcanized inhibitor, and Accelerator TBBS.

10. The method as claimed in one of claims 7 to 9, wherein a size of each of the at least one cavity (212, 302), a shape of each of the at least one cavity (212, 302), and a number of the at least one cavity (212, 302) is customized based on at least one of: dimensions of the elastic body (202, EB), a vehicle type intended to use the airless solid tyre (200, 300), and a desired cushioning effect associated with the airless solid tyre (200, 300).

Images