Low flat radial tire

Abstract

The utility model provides a low-flatness inflatable radial tire, which belongs to the technical field of radial tires and comprises a low-flatness radial tire, a tread, a tire body, a belted layer structure arranged between the tread and the tire body, and belted hooping layers arranged at two ends above the outermost belted layer in the radial direction of the tire, the belted layer structure comprises a first belted layer, a second belted layer and a third belted layer which are sequentially arranged from the inner side to the outer side of the tire, wherein the angle between the first belted layer and the running direction of the tire is 45-70 degrees; the angle between the second belted layer and the running direction of the tire is 15-25 degrees, and the cord thread direction is the same as the arrangement direction of the first belted layer; the angle between the third belted layer and the running direction of the tire is 15-25 degrees, and the inclination direction of the third belted layer is opposite to that of the second belted layer; according to the utility model, the problem of overlarge increase of the cord thread spacing of the edge part of the belted layer under the pressure of the pressure roller in the forming process of the low flat radial tire is solved, so that the durability and the eccentric wear resistance of the tire are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of radial tires, in particular to a low-profile pneumatic radial tire. Background Art

[0002] The belt is the core component of a TBR radial tire. It withstands circumferential tension, tightens the tire carcass, enhances tread strength and stability, and handles impact forces from the road. A TBR belt typically consists of several layers of steel cords angled at specific angles (10° to 60°) to the tire's circumference. The cord spacing and angles of the finished belt significantly impact tire performance, directly affecting tire durability and contact patch.

[0003] During the forming process, the belt layer semi-finished product and the tread components are sequentially attached to the forming drum 2 to form the belt layer and tread composite part 1 (see Figure 1 Since the belt layer is a straight structure, the belt layer and the tread edge are not completely attached. Then, the belt layer and the tread crown composite are attached to the carcass and other components on the shaping drum 3. In order to avoid air pockets, the pressure roller 4 is used to press the tread, belt layer and carcass to make them fit tightly (see Figure 2 ). As the pressure roller presses along the tread from the center to the edge, the tread and belt layer will be subjected to pressure and lateral force. The lateral force will cause the tread and belt layer to extend outward, resulting in an increase in the cord spacing and angle. For conventional aspect ratio tires, this belt layer deformation is relatively small. However, given the structural characteristics of low aspect ratio tires, the cord spacing of the finished belt layer will increase excessively after forming and pressing, which will result in insufficient belt layer tightening force after the finished product is inflated, causing durability and grounding problems. The main reasons are as follows: When the low-profile tire belt layer crown composite is bonded to the carcass on the shaping drum, the belt layer expands radially after the carcass is inflated and in contact with the belt layer. Due to the edge effect of the belt layer (that is, the two ends of the belt layer of the TBR radial tire are free, and the expansion rate of the edge of the belt layer is greater than the expansion rate of the middle part after inflation), the middle of the belt layer expands less, the shoulder expands more, and the belt layer changes from straight to slightly upturned at both ends. The upturned angles at both ends form an angle δ1 (see Figure 3 and Figure 4 The smaller the tire aspect ratio, the greater the belt edge effect, resulting in a larger belt δ1 during molding. The larger δ1 is, the greater the lateral force on the crown and belt (see Figure 5 ), resulting in greater variations in edge cord spacing and angles, poor actual durability and ground contact print (see Figure 6 and Figure 7 ). Summary of the Invention

[0004] This utility model provides a low-profile radial tire. By adjusting the belt width and cooperating with the belt tightening layer, this patent suppresses belt edge warping during the molding process. This reduces the problem of reduced belt cord density at both ends of the finished tire caused by compression of the crown during the molding process, and ensures a uniform belt density variation in the finished tire. This uniform belt density variation in the finished tire contributes to a more rectangular tire footprint, improving crown durability and anti-bias wear performance.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A low-profile radial tire comprising a tread, a carcass, and a belt structure disposed between the tread and the carcass, further comprising belt tightening layers disposed above and at both ends of the radially outermost belt layer of the tire. The belt structure comprises the following arranged in sequence from the inner side of the tire to the outer side:

[0007] a first belt layer, wherein the angle between the first belt layer and the tire running direction is 45° to 70°;

[0008] A second belt layer, wherein the angle between the second belt layer and the tire travel direction is 15° to 25°, and the cord direction is the same as the arrangement direction of the first belt layer;

[0009] A third belt layer, wherein the angle between the third belt layer and the tire running direction is 15° to 25° and the inclination direction is opposite to that of the second belt layer;

[0010] The fourth belt layer has an angle of 15° to 25° with the tire running direction, and the cord inclination direction is the same direction or the opposite direction as that of the third belt layer.

[0011] Preferably, the belt tightening layer is arranged at both ends above the third belt layer, and the belt tightening layer is wound in one layer along the circumferential angle of 0° to 5° of the tire.

[0012] Preferably, the second belt layer width W2 and the tire crown width TW satisfy the following relationship: W2 / TW≥85%.

[0013] Preferably, in the belt structure, the second belt layer has the widest width along the tire axial direction.

[0014] Preferably, the belt tightening layer width W10 and the second belt layer width W2 satisfy the following relationship:

[0015] W10 / W2=15%~25%.

[0016] Preferably, the distance between the outermost end point of the belt tightening layer in the axial direction of the tire and the outermost end point of the third belt layer in the axial direction of the tire is 5 to 10 mm.

[0017] Preferably, the low-profile radial tire further includes a sidewall arranged axially outside the carcass.

[0018] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0019] 1. In the present invention, by limiting the minimum width value of the second belt layer in the belt layer structure, and combining it with the simultaneous limitation of the belt tightening layer width and winding tension, it can be ensured that the edge warping angles of the belt layer structure at both ends are within a reasonable range during the molding process, avoiding the adverse effect on the edge warping angle caused by the second belt layer width being too small, which in turn leads to a decrease in the fastening ability of the belt tightening layer. At the same time, the width limitation scheme of the belt tightening layer can work together with the second belt layer to suppress the belt layer edge warping phenomenon during the molding process, thereby reducing the problem of reduced density of the belt layer cords at both ends of the finished tire caused by the pressure of the crown part during the molding process, and making the density of the finished belt layer change evenly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the belt layer and crown composite part attached to the building drum;

[0021] Figure 2 This is a schematic diagram of the structure of the tire crown and tire body being attached to the shaping drum;

[0022] Figure 3 Schematic diagram of belt expansion when inflating a low-profile tire;

[0023] Figure 4 Schematic diagram of the structure when the belt and crown composite parts and the carcass composite parts are attached;

[0024] Figure 5 This is a schematic diagram of the upward warping of the belt layers at both ends during the shaping process of a low-profile tire;

[0025] Figure 6 Schematic diagram of the force analysis of the belt layer warping on the shaping drum;

[0026] Figure 7 It is a statistical diagram of the spacing and angle changes of the finished products at the edge of the belt layer;

[0027] Figure 8 This is a schematic diagram of the contact patch of a traditional low-profile radial tire;

[0028] Figure 9 A schematic diagram of the structure of a low-profile radial tire provided by the present invention;

[0029] Figure 10 This is a schematic diagram of the structure of the low-profile radial tire belt layer structure connected to the belt tightening layer provided by the utility model;

[0030] Figure 11A schematic diagram of the contact patch of the low-profile radial tire provided by the present invention.

[0031] In the figure: 1. Belt and crown composite; 2. Forming drum; 3. Shaping drum; 4. Pressure roller; 10. Tread; 20. Carcass; 310. First belt layer; 320. Second belt layer; 330. Third belt layer; 340. Fourth belt layer; 40. Belt tightening layer; 50. Sidewall. DETAILED DESCRIPTION

[0032] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] In order to achieve the above purpose, the embodiment of the present utility model adopts the following technical solutions: Figure 9 A low-profile radial tire includes a tread 10, a carcass 20, and a belt layer structure disposed between the tread and the carcass. A sidewall 50 is also disposed axially outward of the carcass 20. Furthermore, the low-profile radial tire includes a belt tightening layer 40 disposed at both ends above the radially outermost belt layer of the tire. Specifically, the belt layer structure includes a first belt layer 310, a second belt layer 320, a third belt layer 330, and a fourth belt layer 340, which are sequentially arranged from the inside of the tire to the outside. Among them, the angle between the first belt layer and the driving direction of the tire is 45°~70°, the angle between the second belt layer and the driving direction of the tire is 15°~25°, and the cord direction of the second belt layer is the same as the arrangement direction of the first belt layer, the angle between the third belt layer and the driving direction of the tire is 15°~25°, and the inclination direction of the third belt layer is opposite to that of the second belt layer, and the angle between the fourth belt layer and the driving direction of the tire is 15°~25°, and the inclination direction of the cord of the fourth belt layer is the same or opposite to that of the third belt layer.

[0034] Further, refer to Figure 10 The belt tightening layer 40 is arranged at both ends above the fourth belt layer 340, and the belt tightening layer is wound in one layer at an angle of 0° to 5° along the circumference of the tire. The fiber cord of the belt tightening layer is aramid fiber. Aramid has the strength of steel wire, and its elongation (≤4%) is higher than that of steel wire. It has the advantages of good toughness and light weight. At the same time, when the belt tightening layer 40 is formed, the winding tension is controlled within the range of 0.6 to 1.2 kgf, which can reduce the expansion of the belt layer during the manufacturing process. At the same time, aramid has a large elongation and is in the outermost layer. Compared with zero-degree steel cord, it has less influence on the force of the belt layer after the tire is inflated.

[0035] Furthermore, the width W10 of the belt tightening layer 40 and the width W2 of the second belt layer 320 satisfy the following relationship: W10 / W2=15%-25%.

[0036] Furthermore, the distance between the outermost end point of the belt tightening layer 40 along the axial direction of the tire and the outermost end point of the third belt layer 330 along the axial direction of the tire is 5 to 10 mm. By staggering the two ends of the belt tightening layer and the third belt layer by 5 to 10 mm, the overlap of the end points of the two and the increased risk of air pockets at that position can be avoided.

[0037] Furthermore, the width W2 of the second belt layer 320 and the tire crown width TW satisfy the following relationship: W2 / TW≥85%. At the same time, in the belt layer structure, the width of the second belt layer 320 along the tire axial direction is the widest. By limiting the minimum value of the second belt layer width W2 to 85%*TW, it can be ensured that the angle δ1 of the belt layer is within a reasonable range during the forming process, thereby avoiding a decrease in the belt tightening layer capacity due to the second belt layer width W2 being too small.

[0038] The technical effects of the present invention are described below through specific comparative examples:

[0039] Experimental object: Low-profile radial tire with a size of 295 / 60R22.5;

[0040] Experimental conditions: air pressure is 900kP, tire load is 3350kg, among which the ratio setting between the second belt layer width W2 and the tread width TW, the ratio setting between the belt tightening layer width and the second belt layer width W2, the belt tightening layer winding tension setting, and the maximum change rate of the cord spacing between the finished product and semi-finished product of the second belt layer are specifically shown in the following table. At the same time, the tire crown durability index (the longer the actual drum test time, the higher the index) and anti-eccentric wear index (the smaller the ratio of the inner / outer ground contact length of the shoulder block, the higher the index) measured in each comparative example are also shown in the table below.

[0041]

[0042]

[0043] Comparative analysis shows that when comparing Example 1 with the traditional example, the W2 width is too low and the belt tightening layer winding tension is too low, and the tire performance is not significantly improved. The three examples show that increasing the belt tightening layer width and the belt tightening layer winding tension, the two can work together to improve the belt layer cord spacing variation, so that the tire performance is correspondingly improved. In addition, combined with Figure 8 and Figure 11 ,in Figure 8 This is the traditional example of a tire contact patch. Figure 11 The tire contact footprint of the embodiment is shown. Through comparison, it is found that the embodiment using the solution of the present application is superior to the traditional tire in terms of tire contact footprint, and can improve the problem of poor contact footprint of low-profile tires.

[0044] The above-described embodiments are merely descriptions of preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A low profile radial tire comprising a tread (10), a carcass (20), and a belt structure arranged between the tread and the carcass, characterized in that: The tire also includes a belt tightening layer (40) arranged at both ends above the outermost belt layer in the tire radial direction. The belt layer structure includes the following layers arranged in sequence from the inner side of the tire to the outer side: a first belt layer (310), wherein the angle between the first belt layer and the tire running direction is 45° to 70°; A second belt layer (320), wherein the angle between the second belt layer and the tire running direction is 15° to 25°, and the cord direction is the same as the arrangement direction of the first belt layer; a third belt layer (330), wherein the angle between the third belt layer and the tire running direction is 15° to 25° and the inclination direction is opposite to that of the second belt layer; The fourth belt layer (340) has an angle of 15° to 25° with the tire running direction, and the inclination direction of the cords is the same direction or the opposite direction to that of the third belt layer.

2. The low-profile radial tire according to claim 1, characterized in that The belt tightening layer (40) is arranged at both ends above the fourth belt layer (340), and the belt tightening layer is wound in one layer at an angle of 0° to 5° along the circumferential direction of the tire.

3. The low-profile radial tire according to claim 2, characterized in that: The width W2 of the second belt layer (320) and the tire crown width TW satisfy the following relationship: W2 / TW≥85%.

4. The low-profile radial tire according to claim 3, characterized in that: In the belt layer structure, the second belt layer (320) has the widest width along the tire axial direction.

5. The low-profile radial tire according to claim 3, characterized in that: The width W10 of the belt tightening layer (40) and the width W2 of the second belt layer (320) satisfy the following relationship: W10 / W2=15% to 25%.

6. The low-profile radial tire according to claim 5, characterized in that The distance between the outermost end point of the belt tightening layer (40) along the axial direction of the tire and the outermost end point of the third belt layer (330) along the axial direction of the tire is 5 to 10 mm.

7. The low-profile radial tire according to claim 6, characterized in that: The low-profile radial tire further comprises a sidewall (50) arranged on the axially outer side of the carcass (20).

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