An n+2 cavity mechanical bionic buffer air cavity hollow tire semi-finished product extrusion molding die assembly

Abstract

The utility model relates to tire technical field discloses a kind of n+2 cavity mechanical bionic buffer air cavity hollow tire semi-finished product extrusion forming die assembly, its structure includes outer mouth shape ring and die core, the die core is detachably coaxially arranged in the inner cavity of the outer mouth shape ring, and annular space between the inner wall of the outer mouth shape ring constitutes the parison runner of hollow tire body. N+2 radially protruding forming ribs are evenly arranged on the outer wall of the die core in the circumferential direction, the end of the forming rib cooperates with the inner wall of the outer mouth shape ring, thereby forming n+2 independent forming runners of n+2 buffer air cavities in the parison runner. The utility model can realize the extrusion forming of n+2 cavity buffer air cavity hollow tire once, and production efficiency is high, and the body structure formed is stable in size, accurate, good in quality.

Description

Technical Field

[0001] This utility model relates to the field of tire technology, and in particular to an extrusion die assembly for a hollow tire semi-finished product with an n+2 cavity biomimetic buffer air cavity. Background Technology

[0002] With the rapid development of shared bicycles and shared electric bikes, the market's demands for vehicle durability and maintenance costs are constantly increasing, leading to growing attention on non-pneumatic tires. One of the core challenges facing the operation of shared bicycles and shared electric bikes is the high cost of tire maintenance. While pneumatic tires have advantages such as light weight, low rolling resistance, and good cushioning performance, they also have fatal drawbacks such as susceptibility to air leaks and blowouts, poor puncture resistance, and frequent maintenance requirements. The main advantage of non-pneumatic tires is that they do not require inflation, relying solely on the tire's own materials and structure to achieve support and cushioning performance. They are puncture-resistant, elastic, wear-resistant, and have low rolling resistance, with a lifespan more than three times that of pneumatic tires, making them an important development direction for the industry. It is projected that the demand for non-pneumatic tires in the shared mobility sector will grow at an average annual rate of over 15% in the next five years. However, non-pneumatic tires generally do not perform as well as pneumatic tires in terms of shock absorption and comfort. This is especially true in the shared electric bike sector, where vehicle weight and speed are higher, placing even stricter demands on the reliability and safety of non-pneumatic tires.

[0003] To ensure load-bearing capacity, existing non-pneumatic tires often employ denser support structures, leading to increased weight. Their cushioning effect relies primarily on material deformation, which is less effective than pneumatic tires at high speeds or on bumpy roads, impacting vehicle range and riding experience. For example, solid tires, while durable, are not widely accepted due to their poor comfort and heavy weight. Insulated tires, made with foam inner tubes, are relatively soft, resulting in significant deformation and heat generation during use. The heat trapped in the inner tube's center is difficult to dissipate, and the heat accumulation effect can exceed the material's temperature limit, causing molecular chain breakage and tire damage. Hollow tires, due to their different internal structures, have significantly impacted performance due to variations in material thickness, shape, and hardness. For instance, thinner tires offer improved comfort but reduced load-bearing capacity, while higher hardness increases load-bearing capacity but reduces comfort and increases susceptibility to cracking. Therefore, a comprehensive evaluation is needed, taking into account tire and rim specifications, customer requirements for tire size, and the quantity and dimensions of the internal structure to create a product that meets customer needs.

[0004] Bionic mechanics, an important branch of bionics, draws inspiration from biology to study the relationship between the macroscopic / microscopic structure of organisms and their mechanical properties, applying these mechanical principles to the design and innovation of engineering structures. It is not merely the imitation of shapes, but a deep understanding of the efficient and energy-saving mechanical principles of biological systems, aiming to solve engineering challenges such as "how to achieve optimal mechanical performance with the least amount of material." In the design of multi-cavity hollow tires, biomimetic graphics can provide a direct geometric model, guiding the design of a lightweight, high-load-bearing, and well-cushioned internal tire structure. The Reuleaux triangle, with its triangular main frame and rounded corners, is a closed curve formed by drawing arcs with the vertices of an equilateral triangle as centers and the side lengths as radii, combining the stability of a triangle with the smoothness of a circle. The arched culvert structure, through the generation of horizontal thrust under vertical loads, disperses pressure downwards and outwards, exhibiting excellent mechanical load-bearing performance. The hemispherical curved surface and longitudinal fine lines of the chestnut shell form a typical thin-shell structure, which can evenly distribute external pressure to the entire surface and avoid local stress concentration. This uniformly curved shape achieves the load-bearing effect of "overcoming rigidity with softness" through geometric curvature.

[0005] A non-pneumatic hollow structure has been designed and developed that can highly simulate the elasticity and strength performance of pneumatic tires, and can also form an effective mechanical dispersion system to reduce tire load and stress concentration during use. This provides users with good driving comfort while extending tire life, and has become a top priority in the research of non-pneumatic tires.

[0006] Currently, most hollow tire extrusion processes involve first extruding a solid tire, then performing secondary processing to form a hollow structure, or using multiple die cores to form separate air cavities before assembling them. These methods result in complex equipment structures, uneven wall thickness in the extruded hollow tires, and unstable internal structures. They are only suitable for simple air cavity structures and also suffer from low production efficiency, difficulty in ensuring the accuracy of air cavity positioning, impact on tire body structural strength, and poor product consistency. Therefore, there is an urgent need for a specialized device capable of achieving one-time, high-efficiency, and high-quality integral forming of porous, buffered air cavity hollow tires. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies by providing an n+2 cavity biomimetic buffer air cavity hollow tire semi-finished product extrusion die assembly. This assembly aims to achieve one-time extrusion molding of porous hollow tire semi-finished products, effectively improving production efficiency and ensuring stable tire structure, precise dimensions, and excellent quality. Furthermore, by adjusting the shape, number, size, and position of the outer die ring, die core, and molding protrusions, a hollow tire that maintains both high mechanical load-bearing capacity and good cushioning comfort can be produced.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] This invention provides an extrusion die assembly for a hollow tire semi-finished product with n+2 cavity biomimetic buffer air chambers, comprising an outer die ring and a die core. The die core is detachably coaxially disposed within the inner cavity of the outer die ring, and forms the preform flow channel of the hollow tire body with the annular space between the die core and the inner wall of the outer die ring. On the outer wall of the die core, n+2 radially protruding forming ridges are uniformly arranged circumferentially. The n+2 forming ridges include two fixed-number forming ridges and n variable-number forming ridges. The ends of the forming ridges are very close to the inner wall of the outer die ring, dividing the preform flow channel into n+2 independent, smoothly shaped sub-channels, thereby forming the prototype of n+2 independent buffer air chambers inside the hollow tire. When the rubber compound flows through, the n+2 buffer air chambers are completely retained inside the tire body, forming a structurally stable n+2 cavity hollow tire in one step.

[0010] More preferably, the constant quantity of formed protrusions includes formed protrusion A and formed protrusion B.

[0011] More preferably, the variable number of forming protrusions includes forming protrusion 1, forming protrusion 2, up to forming protrusion n, where 0 < n ≤ 10, and n is an even natural number.

[0012] More preferably, the cross-section of the formed protruding ridge A end face is a smooth, streamlined inverted culvert arch, including an elliptical top wall and an arched bottom wall, which are connected by two vertical side walls.

[0013] More preferably, the cross-section of the formed convex ridge B end face is a smooth, streamlined, positive straight edge similar to a Lurox triangle, including a left triangular side wall, a right triangular side wall, and a triangular bottom wall, and the left triangular side wall, the right triangular side wall, and the triangular bottom wall are connected by transition arc walls.

[0014] More preferably, the cross-sections of the end faces of the formed protrusions 1 to 2 are all smooth, streamlined, horizontal chestnut shell-like biomimetic patterns, and are of equal size, each including a short arc sidewall and a long arc sidewall. The short arc sidewall and the long arc sidewall of the same formed protrusion are connected by two hemispherical walls.

[0015] More preferably, the forming protrusions A and B are arranged vertically and symmetrically along the vertical center line of the end face cross-section, and are evenly distributed on the upper and lower sides of the horizontal center line of the end face cross-section. The distance between the bottom of the arched bottom wall of the forming protrusion A and the center of the end face cross-section is equal to the distance between the top of the transition arc wall of the forming protrusion B and the center of the end face cross-section.

[0016] More preferably, the number and position of the forming protrusions 1 to n are evenly distributed on the outer wall of the mold core between forming protrusions A and B, symmetrically arranged vertically along the horizontal center line of the end face cross-section, and evenly distributed on both sides of the vertical center line of the end face cross-section, and symmetrically arranged horizontally. The forming protrusions 1 to n are symmetrical along the straight line formed by the center of the end face cross-section and the center of their respective forming protrusions.

[0017] More preferably, 'a' represents the total width of the inner wall of the outer-mouth ring, 'b' represents the total height of the cross-section of the inner wall of the outer-mouth ring, and 'c' represents the width of the contact area between the hollow tire and the rim within the inner wall of the outer-mouth ring. The specific values ​​of 'a', 'b', and 'c' are set according to the tire and rim specifications, customer requirements for tire size, etc. In this invention, the total width 'a' of the inner wall of the outer-mouth ring is 60-100mm, the total height of the cross-section 'b' is 50-100mm, and the width of the contact area 'c' is 50-80mm.

[0018] More preferably, H1 is the distance from the top of the hollow tire mating position of the inner wall of the outer-mouth ring to the top of the elliptical arc top wall of the forming protrusion A, H1=5-20%a·(2^(n / 2)-1) / 2^(n / 2-1); H2 is the distance from the center of the cross-section of the end face of the inner wall of the outer-mouth ring to the bottom of the arched bottom wall of the forming protrusion A, H2=5-15%a·(2^(n / 2)-1) / 2^(n / 2-1); H3 is the distance from the inner wall of the outer-mouth ring to the adjacent forming protrusion A. The distance between the vertical sidewalls is H3 = 15-40%a·(2^(n / 2)-1) / 2^(n / 2-1), D1 is the chord length corresponding to the elliptical arc top wall of the formed convex ridge A, D1 = 15-30%a / 2^(n / 2-1), R1 is the radius of the elliptical arc top wall of the formed convex ridge A, R1 = 6-20%a / 2^(n / 2-1), and R2 is the radius of the arched bottom wall of the formed convex ridge A, R2 = 3-15%a / 2^(n / 2-1).

[0019] More preferably, H4 is the distance from the top of the hollow tire crown in the inner wall of the outer ring to the bottom wall of the triangular side of the shaped protrusion B, H4 = 10-25%a·(2^(n / 2)-1) / 2^(n / 2-1), D2 is the length of the left triangular side wall, right triangular side wall, and bottom wall of the shaped protrusion B, D2 = 15-30%a / 2^(n / 2-1), and R3 is the radius of the transition arc wall of the shaped protrusion B, R3 = 15-30%a / 2^(n / 2-1).

[0020] More preferably, H5 is the distance from the inner wall of the outer ring to the top of the long arc sidewall of the adjacent forming protrusion 1 to forming protrusion n, H5 = 5 - 20%a·(2^(n / 2) - 1) / 2^(n / 2 - 1), H6 is the distance from the center of the cross-section of the inner wall of the outer ring to the top of the short arc sidewall of the adjacent forming protrusion 1 to forming protrusion n, H6 = 5 - 15%a·(2^(n / 2) - 1) / 2^(n / 2 - 1), and H6 = H2, D3 is the chord length of the long arc sidewall of the forming protrusion 1 to forming protrusion n, D 3 = 15-30%a / 2^(n / 2-1), and D1:D3 = 0.5-3:1, D2:D3 = 0.5-6:1, R4 is the radius of the short arc sidewall of the forming ridge 1 to the forming ridge n, R4 = 2-15%a / 2^(n / 2-1), R5 is the radius of the long arc sidewall of the forming ridge 1 to the forming ridge n, R5 = 8-25%a / 2^(n / 2-1), R6 is the radius of the hemispherical wall of the forming ridge 1 to the forming ridge n, R6 = 10-30%a / 2^(n / 2-1).

[0021] More preferably, H7 is the width of the blank flow channel between each pair of adjacent forming protrusions A, 1 to n, and B, and H7 = 10-20%a.

[0022] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0023] This invention provides a die assembly for extruding and molding semi-finished hollow tires with n+2 cavity biomimetic buffer air chambers. Through a uniquely designed die core with n+2 biomimetic cross-sectional protrusions, the molding function of n+2 buffer air chambers is integrated into the die assembly, achieving one-time extrusion molding of the n+2 cavity hollow tire semi-finished product. This completely replaces traditional secondary processing or combined molding processes, resulting in a significant leap in production efficiency. The n+2 buffer air chambers are evenly distributed circumferentially and are entirely encapsulated by the tire body material, resulting in a complete, continuous tire body without internal bonding seams, uniform mechanical properties, and good structural stability. The die assembly precisely ensures the shape, size, and position of the buffer air chambers, resulting in good extrusion consistency and high-quality semi-finished product. The n+2 cavity buffer air chambers have a special shape and arrangement, forming a support system with a constant mechanical relationship, giving the hollow tire reliable elasticity and buffering performance. The die assembly has a simple structure, low manufacturing difficulty and cost, and is easy to assemble, disassemble, and clean, making it easy to promote and use. Attached Figure Description

[0024] Figure 1 This is a schematic diagram (axial sectional view) of the extrusion die assembly for the n+2 cavity biomimetic buffer air cavity of the present invention.

[0025] Figure 2 This is a schematic diagram (end section view) of the extrusion die assembly for the n+2 cavity biomimetic buffer air cavity of the present invention.

[0026] Figure 3 This is a schematic diagram (end section view) of the extrusion die assembly for the hollow tire semi-finished product in the n+2 cavity biomimetic buffer air cavity corresponding to each parameter of this utility model.

[0027] Figure 4 This is a schematic diagram (end section view) of the die assembly for extruding and molding a hollow tire semi-finished product in the four-cavity biomimetic buffer air cavity of Example 1.

[0028] Figure 5 This is a schematic diagram (end section view) of the die assembly structure for extruding a hollow tire semi-finished product in the six-cavity biomimetic buffer air cavity in Example 2.

[0029] Figure 6 This is a schematic diagram (end section view) of the die assembly for extruding and molding a hollow tire semi-finished product in the eight-cavity biomimetic buffer air cavity of Example 3.

[0030] In the figure: (a) outer ring, (b) mold core, (1) blank flow channel, (2) forming ridge A, (21) elliptical arc top wall, (22) arched bottom wall, (23) vertical side wall, (3) forming ridge B, (31) left triangular side wall, (32) right triangular side wall, (33) triangular bottom wall, (34) transition arc wall, (4) forming ridge n, (41) short arc side wall, (42) long arc side wall, (43) hemispherical wall. Detailed Implementation

[0031] The technical solutions of the embodiments of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection claimed by this utility model.

[0032] In the description of the embodiments of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model.

[0033] Examples 1-3

[0034] This invention provides an extrusion die assembly for a hollow tire semi-finished product with n+2 cavity biomimetic buffer air chambers, including an outer die ring (a) and a die core (b). The die core (b) is detachably coaxially disposed in the inner cavity of the outer die ring (a), and the annular space between the die core (b) and the inner wall of the outer die ring (a) forms the blank flow channel (1) of the hollow tire body. On the outer wall of the die core (b), n+2 radially protruding forming ridges are uniformly arranged circumferentially. The n+2 forming ridges include 2 fixed-number forming ridges and n variable-number forming ridges. The ends of the forming ridges are very close to the inner wall of the outer die ring (a), dividing the blank flow channel (1) into n+2 independent, smoothly shaped sub-flow channels, thereby forming the prototype of n+2 independent buffer air chambers inside the hollow tire. When the rubber material flows through, the n+2 buffer air chambers are completely retained inside the tire body, forming a structurally stable n+2 cavity hollow tire in one step.

[0035] More preferably, the constant quantity of forming protrusions includes forming protrusion A (2) and forming protrusion B (3).

[0036] More preferably, the variable number of forming protrusions includes forming protrusion 1, forming protrusion 2, up to forming protrusion n (4), 0 < n ≤ 10, and n is an even natural number.

[0037] More preferably, the cross-section of the end face of the shaped protrusion A (2) is a smooth streamlined inverted culvert arch, including an elliptical top wall (21) and an arched bottom wall (22), and the elliptical top wall (21) and the arched bottom wall (22) are connected by two vertical side walls (23).

[0038] More preferably, the cross-section of the end face of the shaped protrusion B (3) is a smooth streamlined positive straight edge similar to a Lurox triangle, including a left triangular side wall (31), a right triangular side wall (32) and a triangular bottom wall (33), and the left triangular side wall (31), the right triangular side wall (32) and the triangular bottom wall (33) are connected by transition arc walls (34).

[0039] More preferably, the cross-section of the end face of the shaped protrusion 1 up to the shaped protrusion n (4) is a smooth, streamlined horizontal chestnut shell biomimetic pattern, and the size is equal. It includes a short arc sidewall and a long arc sidewall respectively. The short arc sidewall (41) and the long arc sidewall (42) of the same shaped protrusion are connected by two hemispherical walls (43).

[0040] More preferably, the forming protrusions A (2) and B (3) are arranged vertically and symmetrically along the vertical center line of the end face cross-section, and are evenly distributed on the upper and lower sides of the horizontal center line of the end face cross-section. The distance between the bottom of the arched bottom wall (22) of the forming protrusion A (2) and the center of the end face cross-section is equal to the distance between the top of the transition arc wall (34) of the forming protrusion B (3) and the center of the end face cross-section.

[0041] More preferably, the number and position of the forming protrusions 1 to n (4) are evenly distributed on the outer wall of the mold core (b) between the forming protrusions A (2) and B (3), symmetrically distributed vertically along the horizontal center line of the end face cross-section, and evenly distributed on the left and right sides of the vertical center line of the end face cross-section, and symmetrically distributed horizontally. The forming protrusions 1 to n (4) are symmetrical along the straight line formed by the center of the end face cross-section and the center of their respective forming protrusions.

[0042] More preferably, 'a' represents the total width of the inner wall of the outer-mouth ring (a), 'b' represents the total height of the cross-section of the inner wall of the outer-mouth ring (a), and 'c' represents the width of the contact area between the hollow tire and the rim within the inner wall of the outer-mouth ring (a). The specific values ​​of 'a', 'b', and 'c' are set according to the tire and rim specifications, customer requirements for tire size, etc. In this invention, the total width 'a' of the inner wall of the outer-mouth ring (a) is 60-100mm, the total height of the cross-section is 50-100mm, and the width of the contact area is 50-80mm.

[0043] In Examples 1-3, the total width of the inner wall of the outer-mouth ring (a) is a=80mm, the total height of the cross section is b=78mm, and the width of the mating position is c=60mm.

[0044] like Figure 2 , Figure 4-6 As shown in Table 1, the parameters of the die assembly in embodiments 1-3 of this utility model vary with the value of n.

[0045] Table 1 (Unit: mm, except for n)

[0046] Except for the technical features described in the specification, the remaining technical features are known to those skilled in the art. To highlight the innovative features of this utility model, the remaining technical features will not be described in detail here. In summary, the above are merely preferred embodiments of this utility model and should not be construed as limiting the scope of this utility model. That is, any simple equivalent changes and modifications made in accordance with the claims and the content of this utility model specification should still fall within the scope of this utility model patent.

Claims

1. A die assembly for extruding and molding semi-finished hollow tires in an n+2 cavity biomimetic buffer air cavity, comprising: The outer ring (a) and the mold core (b) are characterized in that the mold core (b) is detachably coaxially arranged in the inner cavity of the outer ring (a) and forms a blank flow channel (1) for the hollow tire body with the annular space between the mold core (b) and the inner wall of the outer ring (a). On the outer wall of the mold core (b), n+2 radially protruding forming ridges are uniformly arranged in the circumferential direction. The n+2 forming ridges include 2 fixed-number forming ridges and n variable-number forming ridges. The ends of the forming ridges are very close to the inner wall of the outer ring (a), dividing the blank flow channel (1) into n+2 independent, smooth-shaped sub-flow channels, thereby forming the prototype of n+2 independent buffer air cavities inside the hollow tire. When the rubber material flows through, the n+2 buffer air cavities are completely retained inside the tire body, forming a structurally stable n+2-cavity hollow tire in one step.

2. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity as described in claim 1, characterized in that, The constant quantity of forming protrusions includes forming protrusion A (2) and forming protrusion B (3).

3. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity as described in claim 2, characterized in that, The variable number of forming protrusions includes forming protrusion 1, forming protrusion 2, up to forming protrusion n (4), 0 < n ≤ 10, and n is an even natural number.

4. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity as described in claim 3, characterized in that, The cross-section of the end face of the shaped protrusion A (2) is a smooth streamlined inverted culvert arch, including an elliptical top wall (21) and an arched bottom wall (22), which are connected by two vertical side walls (23).

5. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 4, characterized in that, The cross-section of the end face of the shaped protrusion B (3) is a smooth streamlined positive straight edge similar to a Lurox triangle, including a left triangular side wall (31), a right triangular side wall (32) and a triangular bottom wall (33). The left triangular side wall (31), the right triangular side wall (32) and the triangular bottom wall (33) are connected by transition arc walls (34).

6. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 5, characterized in that, The cross-section of the end face of the shaped protrusion 1 up to the shaped protrusion n (4) is a smooth, streamlined horizontal chestnut shell biomimetic pattern, and the dimensions are equal. They include short arc sidewalls and long arc sidewalls respectively. The short arc sidewall (41) and long arc sidewall (42) of the same shaped protrusion are connected by two hemispherical walls (43).

7. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 5, characterized in that, The forming protrusions A (2) and B (3) are arranged vertically and symmetrically along the vertical center line of the end face cross-section, and are evenly distributed on the upper and lower sides of the horizontal center line of the end face cross-section. The distance between the bottom of the arched bottom wall (22) of the forming protrusion A (2) and the center of the end face cross-section is equal to the distance between the top of the transition arc wall (34) of the forming protrusion B (3) and the center of the end face cross-section.

8. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 6, characterized in that, The number and position of the forming protrusions 1 to n (4) are evenly distributed on the outer wall of the mold core (b) between the forming protrusions A (2) and B (3), symmetrically distributed on the horizontal center line of the end face cross-section, and evenly distributed on the left and right sides of the vertical center line of the end face cross-section and symmetrically distributed on the left and right sides. The forming protrusions 1 to n (4) are symmetrical along the straight line formed by the center of the end face cross-section and the center of their respective forming protrusions.

9. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 6, characterized in that, The total width a of the inner wall of the outer-mouth ring (a) is 60-100mm, the total height b of the inner wall section of the outer-mouth ring (a) is 50-100mm, and the width c of the contact position between the hollow tire and the rim in the inner wall of the outer-mouth ring (a) is 50-80mm.

10. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 9, characterized in that, The distance H1 from the top of the hollow tire mating position of the inner wall of the outer ring (a) to the top of the elliptical arc top wall (21) of the forming ridge A (2) is 5-20%a·(2^(n / 2)-1) / 2^(n / 2-1), the distance H2 from the center of the cross-section of the inner wall end face of the outer ring (a) to the bottom of the arched bottom wall (22) of the forming ridge A (2) is 5-15%a·(2^(n / 2)-1) / 2^(n / 2-1), and the distance H2 from the inner wall of the outer ring (a) to the bottom of the adjacent forming ridge A (2) is 5-15%a·(2^(n / 2)-1) / 2^(n / 2-1). The distance H3 of the vertical sidewall (23) is 15-40%a·(2^(n / 2)-1) / 2^(n / 2-1), the chord length D1 of the elliptical arc top wall (21) of the shaped convex ridge A (2) is 15-30%a / 2^(n / 2-1), the radius R1 of the elliptical arc top wall (21) of the shaped convex ridge A (2) is 6-20%a / 2^(n / 2-1), and the radius R2 of the arched bottom wall (22) of the shaped convex ridge A (2) is 3-15%a / 2^(n / 2-1).

11. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 9, characterized in that, The distance H4 from the top of the hollow tire crown in the inner wall of the outer ring (a) to the bottom wall (33) of the triangular side of the shaped ridge B (3) is 10-25%a·(2^(n / 2)-1) / 2^(n / 2-1), the length D2 of the left triangular side wall (31), right triangular side wall (32), and bottom wall (33) of the shaped ridge B (3) is 15-30%a / 2^(n / 2-1), and the radius R3 of the transition arc wall (34) of the shaped ridge B (3) is 15-30%a / 2^(n / 2-1).

12. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 10, characterized in that, The distance H5 from the inner wall of the outer ring (a) to the top of the long arc sidewall (42) of the adjacent forming ridge 1 up to the forming ridge n (4) is 5-20%a·(2^(n / 2)-1) / 2^(n / 2-1), the distance H6 from the center of the cross-section of the inner wall of the outer ring (a) to the top of the short arc sidewall (41) of the adjacent forming ridge 1 up to the forming ridge n (4) is 5-15%a·(2^(n / 2)-1) / 2^(n / 2-1), and H6=H2, the chord length D of the long arc sidewall (42) of the forming ridge 1 up to the forming ridge n (4) is... 3 = 15-30%a / 2^(n / 2-1), and D1:D3 = 0.5-3:1, D2:D3 = 0.5-6:1, the radius value R4 of the short arc sidewall (41) of the forming ridge 1 to the forming ridge n (4) is 2-15%a / 2^(n / 2-1), the radius value R5 of the long arc sidewall (42) of the forming ridge 1 to the forming ridge n (4) is 8-25%a / 2^(n / 2-1), and the radius value R6 of the hemispherical wall (43) of the forming ridge 1 to the forming ridge n (4) is 10-30%a / 2^(n / 2-1).

13. The extrusion die assembly for a semi-finished hollow tire in an n+2 cavity biomimetic buffer air cavity according to claim 9, characterized in that, The width H7 of the preform flow channel (1) between each pair of the adjacent forming ridges A (2), forming ridge 1 up to forming ridge n (4), forming ridge B (3) is 10-20%a.

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