Agricultural radial tire belt structure

Abstract

This utility model provides a belt layer structure for agricultural radial tires. The belt layer structure consists of an adhesive film, a padding film, a first transition film, belt layer components, and a second transition film from the inside out. The belt layer components are composed of first, second, third, fourth, fifth, and sixth belt layers stacked from bottom to top. Odd-numbered layers are wide belt layers, and even-numbered layers are narrow belt layers. The difference 'a' between the same-side endpoints of adjacent belt layers is 20-25 mm. The cord angles of the first and second belt layers, the third and fourth belt layers, and the fifth and sixth belt layers are 60°-63°, 64°-66°, and 68°-70°, respectively, and the cord angles of the odd-numbered and even-numbered belt layers are opposite. Under low-pressure operation, the ground contact mark is a regular ellipse, close to a rectangle, with clear edges. This not only meets the requirements of high puncture resistance, good high-speed performance, and low cost for agricultural tractor tires, but also reduces soil compaction and protects arable land.

Description

Technical Field

[0001] This utility model relates to the field of agricultural tire manufacturing technology, specifically to an agricultural radial tire belt layer structure. Background Technology

[0002] Agricultural tires, as key components of modern agricultural machinery, directly impact agricultural production efficiency and soil conservation. By 2025, China's planned annual tire production target is 704 million units, with a radialization rate of 96%. However, the radialization rate of agricultural tires is only 16%, far below the prevalence of all-steel and semi-steel radial tires. Particularly in the original equipment tire market for tractors, domestic agricultural tires are still dominated by bias-ply tires, with a radialization rate of less than 5%.

[0003] Agricultural tires include tractor tires, trailer and implement tires, agricultural truck tires, forestry tires, etc. The requirements for different types of agricultural tires vary depending on the vehicle's operating environment, as shown in the table below: For tractor tires, the requirements include low-pressure operation to reduce soil compaction, excellent puncture resistance, good high-speed driving capability, and low-cost control. Generally speaking, the shape of the tire's contact patch and the uniformity of its pressure distribution are crucial for low-pressure operation and reducing soil compaction. The closer the contact patch shape is to a rectangle, the more uniform the ground pressure distribution. This not only helps improve tire wear resistance, handling stability, and safety, but also effectively reduces soil compaction and protects arable land quality. However, for agricultural tires, the tread pattern is usually herringbone. Compared to block tread tires, the contact patch of herringbone tires cannot achieve an ideal rectangle. The ideal state is an ellipse (close to a rectangle), but traditional agricultural bias-ply tires, due to structural limitations, can only produce a flattened ellipse with an extremely uneven ground pressure distribution. Especially under low-pressure and large-deformation conditions, the uneven ground pressure distribution easily leads to excessive wear on the tire shoulder and increased soil compaction. Utility Model Content

[0004] To address the aforementioned problems, this utility model provides an agricultural radial tire belt layer structure.

[0005] This utility model is achieved in the following manner: An agricultural radial tire belt layer structure is disclosed. The belt layer structure comprises, from the inside out, an adhesive film, a gasket, a first transition film, a belt layer component, and a second transition film. The belt layer component is composed of, from bottom to top, a first belt layer, a second belt layer, a third belt layer, a fourth belt layer, a fifth belt layer, and a sixth belt layer stacked together. Odd-numbered belt layers are wide belt layers, and even-numbered belt layers are narrow belt layers. The difference 'a' between the endpoints on the same side of adjacent belt layers is 20-25 mm. The cord angle between the first and second belt layers is 60°-63°, the cord angle between the third and fourth belt layers is 64°-66°, and the cord angle between the fifth and sixth belt layers is 68°-70°. Furthermore, the cord angles of the odd-numbered and even-numbered belt layers are opposite in direction.

[0006] Preferably, the first belt layer and the second belt layer have the same cord angle, the third belt layer and the fourth belt layer have the same cord angle, and the fifth belt layer and the sixth belt layer have the same cord angle.

[0007] Preferably, the difference c between the endpoint C of the first transition film and the endpoint A on the same side of the second belt layer is 15~20mm, the difference d between the endpoint D of the second transition film and the endpoint A on the same side of the second belt layer is 30~50mm, the adhesive film is symmetrically arranged along the center line of the belt layer width direction, the adhesive film is located below the padding adhesive, and the difference f between the outer endpoint K of the adhesive film and the endpoint B of the first belt layer is 20mm-40mm.

[0008] Preferably, the thickness of the first transition film and the second transition film is 2-3 mm.

[0009] Preferably, the thickness of the adhesive film is 1.2~1.8mm.

[0010] Preferably, the cords in the belt layer are polyester cords.

[0011] Compared to existing technologies, the belt layer component of this invention consists of six belt layers, stacked sequentially from bottom to top as a first belt layer, a second belt layer, a third belt layer, a fourth belt layer, a fifth belt layer, and a sixth belt layer. Odd-numbered belt layers are wide belt layers, and even-numbered belt layers are narrow belt layers. The difference in length (a) between adjacent belt layers is 20-25 mm. The cord angle between the first and second belt layers is 60°-63°, and the cord angle between the third and fourth belt layers is 64°-65°. The fifth and sixth belt layers have a cord angle of 68°-70°, and the cord angles of odd-numbered and even-numbered belt layers are opposite. Under low-pressure operation, the grounding mark is elliptical (close to rectangular) with clear edges. This not only meets the requirements of high puncture resistance, good high-speed performance and low cost for agricultural tractor tires, but also reduces soil compaction and protects arable land. It solves the problem that the grounding mark cannot reach the ideal state under low-pressure operation due to the belt layer in the radialization process of existing agricultural tires. Attached Figure Description

[0012] Figure 1 This is a structural schematic diagram of one embodiment of the present invention.

[0013] Figure 2 This is a schematic diagram of the tire cross-section in one embodiment of the present invention.

[0014] Figure 3 This is a schematic diagram of another embodiment of the present invention.

[0015] Figure 4 This is a schematic diagram of the ground contact mark of the tire of this utility model.

[0016] Among them, 1 is the adhesive film; 2 is the gasket; 3 is the first transition film; 4 is the first belt layer; 5 is the second belt layer; 6 is the third belt layer; 7 is the fourth belt layer; 8 is the fifth belt layer; 9 is the sixth belt layer; 10 is the second transition film; 11 is the tread; 12 is the sidewall rubber; 13 is the bead protector; and 14 is the bead wrap. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer with the description. However, unless otherwise specified, the specific experimental methods involved in the following embodiments are conventional methods or implemented according to the conditions recommended in the manufacturer's instructions.

[0018] See Figures 1-4 ,in Figures 1-3As part of a symmetrical diagram, with the other side symmetrical to it, an agricultural radial tire belt layer structure is described. The belt layer structure, from bottom to top, consists of an adhesive sheet 1, a padding rubber 2, a first transition sheet 3, belt layer components, and a second transition sheet 10. A tread 11 is positioned above the belt layer structure, and the tire carcass is positioned below it. The belt layer components, from bottom to top, are composed of a first belt layer 4, a second belt layer 5, a third belt layer 6, a fourth belt layer 7, a fifth belt layer 8, and a sixth belt layer 9, stacked together. Odd-numbered belt layers are wide belt layers, and even-numbered belt layers are narrow belt layers. The difference 'a' between the endpoints on the same side of adjacent belt layers is 20-25 mm. Specifically, the belt layer components are formed by alternating narrow and wide belt layers. The centerline of each belt layer in the width direction coincides with the circumferential center plane of the tire. The belt layer width of odd-numbered layers is... The belt layers of even-numbered layers are of equal width, and the belt layers of odd-numbered layers are all wider than those of even-numbered layers. Among them, the first belt layer 4, the third belt layer 6, and the fifth belt layer 8 are wide belt layers, with their endpoints on the same side being point A. The second belt layer 5, the fourth belt layer 7, and the sixth belt layer 9 are narrow belt layers, with their endpoints on the same side being point B. That is, the horizontal distance between the endpoints A and B of adjacent wide and narrow belt layers on the same side is the difference 'a' between the endpoints on the same side of adjacent belt layers, which is 20~25mm. The difference between belt layers can disperse end stress, avoid cord breakage, reduce interlayer shear stress, and prevent delamination. The wide belt layer covers the end of the narrow belt layer, forming a physical barrier, inhibiting crack propagation, and reducing the risk of delamination in the tire shoulder area. The alternating arrangement of wide and narrow belt layers reduces pressure fluctuations in the grounding area and avoids uneven grounding pressure distribution, which can cause local wear. The cord angle between the first belt layer 4 and the second belt layer 5 is 60°-63°, the cord angle between the third belt layer 6 and the fourth belt layer 7 is 64°-66°, and the cord angle between the fifth belt layer 8 and the sixth belt layer 9 is 68°-70°. The cord angles of the odd-numbered and even-numbered belt layers are opposite. The cord angle refers to the angle between the cord in each polyester ply and the circumferential line of the crown. The cords of adjacent belt layers extend in opposite directions: specifically, the cords of the first belt layer 4, the third belt layer 6, and the fifth belt layer 8 extend to the right, while the cords of the second belt layer 5, the fourth belt layer 7, and the sixth belt layer 9 extend to the left. The cord extension direction of the belt layers must follow the direction of the tire carcass cords. The setting of the belt layer cord angles ensures that the tire's contact patch is elliptical (close to rectangular), improving the continuity of the tread pattern and reducing soil compaction. Figure 4 As shown, a finite element analysis was performed on a tire with the belt layer structure of this utility model. Under the conditions of air pressure of 160 kPa and load of 1950 kg, the tire's ground contact mark is elliptical with clear edges.

[0019] Furthermore, the first belt layer 4 and the second belt layer 5 have the same cord angle, the third belt layer 6 and the fourth belt layer 7 have the same cord angle, and the fifth belt layer 8 and the sixth belt layer 9 have the same cord angle. Specifically, the cord angles of the first belt layer 4 and the second belt layer 5 are 60°, 61°, 62°, or 63°; the cord angles of the third belt layer 6 and the fourth belt layer 7 are 64°, 65°, or 66°; and the cord angles of the fifth belt layer 8 and the sixth belt layer 9 are 68°, 69°, or 70°. The symmetrical and consistent angles of the belt layers ensure a uniform stress distribution and good durability, further guaranteeing that the tire contact patch is elliptical (close to rectangular).

[0020] The centerline of the first transition film 3 in the width direction coincides with the circumferential center plane of the tire. The difference c between the endpoint C of the first transition film 3 and the endpoint A on the same side of the second belt layer 5 is 15~20mm, that is, the horizontal distance c between the endpoint C of the first transition film 3 and the endpoint A of the second belt layer 5 is . The first transition film 3 is located between the gasket and the belt layer components, and is used to bond and fix the gasket and the belt layer components to prevent delamination. The first transition film 3 also plays a role in isolation, preventing the gasket from seeping into the belt layer components and damaging the bonding force between the belt layer overlay and the polyester cord, making the structure of the belt layer less susceptible to damage and preventing cracking at the endpoints of the belt layer during long-term tire use. The first transition film uses a low-heat-generating rubber compound to improve tire durability.

[0021] The centerline of the second transition film 10 in the width direction coincides with the circumferential center plane of the tire. The difference d between the end point D of the second transition film 10 and the end point A on the same side of the second belt layer 5 is 30~50mm, that is, the horizontal distance between the end point D of the second transition film 10 and the end point A of the second belt layer 5 is d. The second transition film 10 is located between the belt layer component and the tread and is used to bond and fix the belt layer component and the tread to avoid delamination.

[0022] The adhesive film 1 is symmetrically arranged along the centerline of the belt layer width direction. The adhesive film 1 is located below the padding rubber. The difference f between the outer end point K of the adhesive film 1 and the end point B of the first belt layer 4 is 20mm-40mm. The adhesive film firmly bonds the padding rubber to the tire carcass, preventing shoulder gaps. In addition, the adhesive film is located at the end of the belt layer, which also serves to fill the gaps. Combined with the end difference of the belt layer, it helps to relieve end stress.

[0023] Furthermore, the thickness of both the first transition film 3 and the second transition film 10 is 2~3mm, preferably 2.5mm. The second transition film 10 is wider than the first transition film 3, and the difference between their endpoints is 10~20mm.

[0024] Furthermore, the thickness of the adhesive film 1 is 1.2~1.8mm, preferably 1.5mm. In one embodiment, depending on the tire size, the width of the second transition film 10 is 550 mm or 750 mm, and correspondingly, the width of the first transition film is 530 mm or 730 mm. The width of the adhesive film 1 is 150 mm, 250 mm, or 350 mm.

[0025] Furthermore, if the ends of the belt layer curve upwards or downwards, it will cause the belt layer edges to become sparse, the distribution of the cords at the ends to be uneven, and the density to vary. This can lead to separation between cords and between cords and the rubber compound, resulting in heat generation during operation and ultimately causing shoulder gaps. To prevent shoulder gaps, a pad 2 is placed below the first transition rubber sheet 3 to ensure that the ends of the belt layer component are horizontal. The overlap area between the pad 2 and the entire belt layer component is located at the end of the belt layer component, i.e., the tire shoulder area. The cross-section of the pad 2 is trapezoidal, forming four endpoints: E, F, G, and H. EH is the lower base of the trapezoid, FG is the upper base, and EF and HG are the two legs of the trapezoid. The inner endpoint E of the pad 2 is far from the tire shoulder point P. The horizontal distance g is 150mm-200mm. The shoulder point P is the intersection of the running surface arc and the sidewall arc on the tire cross section. The difference e between the inner end point E of the pad rubber 2 and the outermost end point A of the belt layer is 40-80mm. The F point of the pad rubber 2 is located inside the outermost end point A of the belt layer. At the same time, the horizontal distance between points E and F is greater than the horizontal distance between points G and H, forming a single-sided thin-edged rubber sheet. In the formed agricultural radial tire, the plane between E and F of the pad rubber is bonded to the first transition rubber sheet 3. The plane between E and H of the pad rubber is bonded to the tire body through the adhesive rubber sheet. The pad rubber 2 is set between the first transition rubber sheet 3 and the tire body, so that the end point of the belt layer is set horizontally.

[0026] The gasket 2 needs to be matched with the belt layer component. Its thickness, width, and position can be adjusted as needed to suit tires of different sizes. The gasket 2 has different thickness requirements in different series: 85 series can be 16mm, 25mm, or 35mm; 65 series can be 20mm or 30mm; and 70 series can be 28mm or 40mm. The thickness of the gasket 2 refers to the vertical distance between the endpoints EF.

[0027] Furthermore, the pad 2 can be configured in two ways: one is that the pad 2 and the sidewall rubber 12 form an integral structure, and the other is that the pad 2 is configured separately; for example... Figures 1-2 As shown, the padding adhesive 2 and the sidewall adhesive 12 form an integrated structure to create a crown-covering side structure, resulting in high molding efficiency and simple operation. The difference b between the outer end point K of the adhesive film 1 and the end point C of the first transition film 3 is 15~20mm.

[0028] like Figure 3 As shown, the pad 2 is set separately, and the pad is set separately from the sidewall rubber 12 to form a side crown structure, which can improve the sidewall flexibility; the sidewall width can be reduced by 8-10mm, improving tire uniformity; the semi-finished product is fuller and has better dynamic balance performance; the molding complexity is reduced; the pad flexural deformation at the tire shoulder area is reduced, and heat generation is reduced. The outer end point of the adhesive sheet 1 is located outside the end point C of the first transition sheet 3.

[0029] The lower end point I of the sidewall rubber 12 is located at the rim lug, which is the contact area between the rim flange and the bead protector.

[0030] Therefore, this invention employs a suitable gasket placed between the belt layer and the tire carcass to reduce the curvature of the belt layer component, ensuring that the ends of the belt layer neither curl upwards nor sag downwards. This guarantees the parallelism of the belt layer component ends, eliminating sharp stress concentration points caused by "curving upwards" or "sags," ensuring stable deformation of the belt layer during tire use, more uniform stress distribution, and improved tire durability. Furthermore, the gasket uses a low-heat-generating material to reduce heat generation.

[0031] A first transition film is used to transition the gasket and belt layer components at the overall junction area to improve adhesion.

[0032] In this invention, the first belt layer to the sixth belt layer are all made of polyester cord calendering and coating; the adhesive film, the first transition film 3, and the second transition film 10 are all calendered by a composite extruder; and the padding adhesive 2 is extruded by an extrusion extruder.

[0033] This utility model of agricultural radial tire uses a 6-layer polyester cord belt layer, which, compared to the traditional nylon buffer layer, can ensure greater load capacity and enhance the load-bearing capacity of agricultural tires. The belt layer uses polyester, with a suitable cutting angle and elongation coefficient, which minimizes cross-sectional width expansion while ensuring the outer diameter of the product, thus improving the thermal shrinkage of the agricultural tire cord. The 6-layer cross-belt layer structure ensures that the product imprint is rectangular, improving the continuity of the product pattern and reducing soil compaction. Low heat-generating rubber is added between the tire body and the belt layer. Adhesive sheets are added to the belt layer and the tread to improve adhesion and increase the service life of agricultural tires.

[0034] The above description is only a preferred embodiment of the present utility model. It should be noted that those skilled in the art can make several changes and improvements without departing from the overall concept of the present utility model, and these should also be considered within the protection scope of the present utility model.

Claims

1. An agricultural radial tire belt structure characterized by, The belt layer structure consists of an adhesive film (1), a padding film (2), a first transition film (3), a belt layer component, and a second transition film (10) from the inside out. The belt layer component is composed of a first belt layer (4), a second belt layer (5), a third belt layer (6), a fourth belt layer (7), a fifth belt layer (8), and a sixth belt layer (9) stacked from bottom to top. Among them, the odd-numbered belt layers are wide belt layers, and the even-numbered belt layers are wide belt layers. The layer is a narrow belt layer, and the difference a between the same end points of adjacent belt layers is 20~25mm; the cord angle between the first belt layer (4) and the second belt layer (5) is 60°-63°, the cord angle between the third belt layer (6) and the fourth belt layer (7) is 64°-66°, the cord angle between the fifth belt layer (8) and the sixth belt layer (9) is 68°-70°, and the cord angle direction of the odd-numbered belt layers is opposite to that of the even-numbered belt layers.

2. The agricultural radial tire belt structure of claim 1 wherein, The first belt layer (4) and the second belt layer (5) have the same cord angle, the third belt layer (6) and the fourth belt layer (7) have the same cord angle, and the fifth belt layer (8) and the sixth belt layer (9) have the same cord angle.

3. The agricultural radial tire belt structure of claim 2 wherein, The difference between the endpoint C of the first transition film (3) and the endpoint A of the second belt layer (5) on the same side is 15~20mm. The difference between the endpoint D of the second transition film (10) and the endpoint A of the second belt layer (5) on the same side is 30~50mm. The adhesive film (1) is symmetrically arranged on the left and right sides along the center line of the belt layer width direction. The adhesive film (1) is located below the pad adhesive (2). The difference between the outer endpoint K of the adhesive film (1) and the endpoint B of the first belt layer (4) is 20mm-40mm.

4. The agricultural radial tire belt structure of claim 3 wherein, The thickness of the first transition film (3) and the second transition film (10) is 2~3mm.

5. The agricultural radial tire belt structure of claim 4 wherein, The thickness of the adhesive film (1) is 1.2~1.8mm.

6. An agricultural radial tire belt structure in accordance with claim 5 wherein, The cords in the belt layer are polyester cords.

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