Tire

Abstract

To provide a tire that can be suppressed from deteriorating in durability due to crack extension in a belt layer, while using a reinforcement belt using a cord extending along a tire width direction and a tire radial direction.SOLUTION: A pneumatic tire 10 comprises: a carcass 40 forming a tire skeleton; a pair of crossing belts 51 and 52, provided outside in a tire radial direction of the carcass 40, in which belt cords 51a and belt cords 52a cross each other; a first reinforcement belt 54 provided closer to outside in the tire radial direction than the crossing belts and extended along a tire width direction and the tire radial direction to cover a plurality of first reinforcement cords 54a arranged separately from each other with a predetermined interval; and a second reinforcement belt 55 provided among the carcass 40 and the crossing belts and extended along the tire width direction and the tire radial direction to cover a plurality of second reinforcement cords 55a arranged separately from each other with a predetermined interval.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a tire including a reinforcement belt covering a first reinforcement cord extending along the tire width direction and the tire radial direction. [Background technology]

[0002] Conventionally, pneumatic tires (hereinafter referred to as tires as appropriate) have a pair of intersecting belts with cords intersecting on the tire radially inner side of the tread that comes into contact with the road surface, and are structured to include a spiral belt (belt reinforcing layer) with cords extending in the tire circumferential direction, and a belt (protective layer) with cords extending in the tire width direction and tire radial direction (see Patent Document 1).

[0003] In a tire equipped with such a reinforcing belt, the protective layer suppresses the tensile strain of the cords in the belt reinforcement layer, thereby achieving both maintaining vehicle handling stability and improving tire durability, particularly in the final stages of tire wear. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5084834 Summary of the Invention [Problem to be solved by the invention]

[0005] In a tire equipped with the above-described reinforcing belt, the belt layer as a whole has high rigidity, but on the other hand, there is a large difference in rigidity between the reinforcing belt and the intersecting belt, etc. Therefore, cracks are likely to occur in the belt layer due to such a difference in rigidity, which may cause a breakdown.

[0006] Therefore, the following disclosure has been made in consideration of the above circumstances, and aims to provide a tire that can suppress a decrease in durability due to crack propagation in the belt layer while using a reinforcing belt made of cords extending along the tire width direction and the tire radial direction. [Means for solving the problem]

[0007] One aspect of the present disclosure is a tire (pneumatic tire 10) including a carcass (carcass 40) that forms a tire skeleton, and a pair of intersecting belts (intersecting belt 51, intersecting belt 52) ​​that are provided radially outward of the carcass and have cords (belt cord 51a, belt cord 52a) that intersect, and the tire is also provided with a first reinforcing belt (first reinforcing belt 54) that is provided radially outward of the intersecting belts, extends along the tire width direction and the tire radial direction, and covers a plurality of first reinforcing cords (first reinforcing cords 54a) that are arranged at a predetermined distance apart, and a second reinforcing belt (second reinforcing belt 55) that is provided between the carcass and the intersecting belts, extends along the tire width direction and the tire radial direction, and covers a plurality of second reinforcing cords (second reinforcing cords 55a) that are arranged at a predetermined distance apart. [Effects of the Invention]

[0008] According to the above-described tire, a decrease in durability due to the progression of cracks in the belt layer can be suppressed while using a reinforcing belt using cords extending in the tire width direction and the tire radial direction. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a pneumatic tire 10. [Figure 2] FIG. 2 is an enlarged cross-sectional view of a portion of the pneumatic tire 10. As shown in FIG. [Figure 3] FIG. 3 is a partially exploded plan view of the carcass 40 and the belt layer 50. As shown in FIG. [Figure 4] FIG. 4 is an explanatory diagram (part 1) of the mechanism by which the second reinforcing belt (lower reinforcing belt) suppresses deformation of the tire ground contact area. [Figure 5] FIG. 5 is an explanatory diagram (part 2) of the mechanism by which the second reinforcing belt (lower reinforcing belt) suppresses deformation of the tire ground contact area. [Figure 6] FIG. 6 is an explanatory diagram (part 3) of the mechanism by which the second reinforcing belt (lower reinforcing belt) suppresses deformation of the tire ground contact area. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0011] (1) Overall tire configuration Fig. 1 is a cross-sectional view of a pneumatic tire 10 according to this embodiment. Specifically, Fig. 1 is a cross-sectional view of the pneumatic tire 10 taken along the tire width direction and tire radial direction. Note that cross-sectional hatching is omitted in Fig. 1 (the same applies below). A tire equator line CL indicates the center of the pneumatic tire 10 in the tire width direction and tire circumferential direction.

[0012] The pneumatic tire 10 can be used for a general four-wheeled passenger vehicle, but can be suitably used for a high-performance vehicle with particularly high maneuverability.

[0013] As shown in FIG. 1, a pneumatic tire 10 includes a tread 20, a tire side portion 30, a carcass 40, a belt layer 50, and a bead portion 60.

[0014] The tread 20 is the portion that comes into contact with the road surface. A pattern (not shown) is formed on the tread 20 according to the usage environment of the pneumatic tire 10 and the type of vehicle on which it is mounted. The tread 20 may be formed with circumferential grooves 21 that extend in the circumferential direction of the tire to ensure drainage performance at least on wet road surfaces.

[0015] The tire side portion 30 is continuous with the tread 20 and is located on the tire radially inward side of the tread 20. The tire side portion 30 is a region from the outer end of the tread 20 in the tire width direction to the upper end of the bead portion 60. The tire side portion 30 may also be called a sidewall or the like.

[0016] The carcass 40 forms the skeleton (tire skeleton) of the pneumatic tire 10. The carcass 40 is provided on the tire radial direction inner side of the belt layer 50. In the embodiment, the carcass 40 has a two-ply structure.

[0017] The carcass 40 has a radial structure in which carcass cords 40a (not shown in FIG. 1, see FIG. 3) arranged radially in the tire radial direction are covered with a rubber material. However, the carcass 40 is not limited to a radial structure, and may have a bias structure in which the carcass cords 40a are arranged to cross each other in the tire radial direction.

[0018] An inner liner may be provided on the inner side of the carcass 40 in the tire radial direction to prevent leakage of gas such as air filled in the internal space of the pneumatic tire 10 mounted on a rim wheel (not shown).

[0019] The belt layer 50 is provided on the inner side in the tire radial direction of the tread 20. The belt layer 50 may be composed of a plurality of belts. Specifically, the belt layer 50 includes a pair of intersecting belts, specifically, an intersecting belt 51 and an intersecting belt 52.

[0020] The intersecting belts 51 and 52 are provided on the outer side in the tire radial direction of the carcass 40. The intersecting belt 52 is provided on the outer side in the tire radial direction of the intersecting belt 51. The width of the intersecting belt 51 may be wider or shorter than the width of the intersecting belt 52.

[0021] The intersecting belts 51 and 52 have belt cords. Specifically, in a tread surface view, a belt cord 51a (not shown in FIG. 1, see FIG. 3) of the intersecting belt 51 intersects with a belt cord 52a (see FIG. 3) of the intersecting belt 52.

[0022] The belt layer 50 may include a reinforcing belt that reinforces the structure of the pneumatic tire 10, in addition to the intersecting belts 51 and 52. In this embodiment, the belt layer 50 includes a cap belt 53, a first reinforcing belt 54, and a second reinforcing belt 55. The cap belt 53 may also be considered as a type of reinforcing belt.

[0023] The cap belt 53 is provided between the intersecting belt 52 and the first reinforcing belt 54. The cap belt 53 has reinforcing cords 53a (not shown in FIG. 1, see FIG. 3) extending in the tire circumferential direction. As shown in FIG. 1, the cap belt 53 is preferably shaped to cover the outer ends of the intersecting belts 51 and 52 in the tire width direction.

[0024] The first reinforcement belt 54 is provided on the outer side in the tire radial direction than the intersecting belts 51 and 52. In the present embodiment, the first reinforcement belt 54 is provided on the outer side of the cap belt 53 in the tire width direction.

[0025] The second reinforcing belt 55 is provided between the carcass 40 and the intersecting belt. In the present embodiment, the second reinforcing belt 55 is provided between the carcass 40 and the intersecting belt 51 of the pair of intersecting belts that is provided on the inner side in the tire radial direction.

[0026] The bead portion 60 is continuous with the tire side portion 30 and is located radially inward of the tire side portion 30. The bead portion 60 is locked to a rim wheel (not shown).

[0027] (2) Configuration of the belt layer 50 Fig. 2 is a partially enlarged cross-sectional view of the pneumatic tire 10. Specifically, Fig. 2 shows a cross-section of one side of the pneumatic tire 10 based on the tire equator line CL. Fig. 3 is a partially exploded plan view of the carcass 40 and the belt layer 50.

[0028] 2 and 3, the carcass 40 has a main body portion 41 and a folded-up portion 42. The main body portion 41 is provided across the tread 20, the tire side portions 30, and the bead portions 60, and is the portion that extends up to the bead portions 60 where it is folded up.

[0029] The folded-up portion 42 is a portion that is continuous with the main body portion 41 and folded back to the outside in the tire width direction via the bead portion 60. In this embodiment, a folded-up end 42e, which is the outer end of the folded-up portion 42 in the tire width direction, is provided so as to contact the intersecting belt 51. Such a structure of the carcass 40 may be called an envelope structure or the like. The folded-up end 42e does not contact the second reinforcing belt 55, and a gap may be provided between the folded-up portion 42 and the second reinforcing belt 55.

[0030] The folded end 42e does not necessarily have to extend to the position of the intersecting belt 51, and may have a structure in which it terminates at the center of the tire side portion 30 in the tire radial direction (high turn-up structure).

[0031] The carcass 40 is formed by covering carcass cords 40a with a rubber material. The material of the carcass cords 40a is not particularly limited, but the carcass cords 40a can be formed using, for example, organic fiber or steel.

[0032] The intersecting belt 51 has belt cords 51a. The belt cords 51a are provided inclined with respect to the tire width direction (and tire circumferential direction). In this embodiment, the angle α (acute angle side) formed by the belt cords 51a with the tire width direction, specifically, angle α1, is approximately 45 degrees.

[0033] The intersecting belt 52 has belt cords 52a. The belt cords 52a are provided inclined with respect to the tire width direction (and tire circumferential direction). In this embodiment, the angle α (acute angle side) formed by the belt cords 52a with the tire width direction, specifically, angle α2, is approximately 45 degrees.

[0034] In this embodiment, the belt cords 51a and 52a are formed using steel. In this manner, the belt cords 51a and 52a are arranged to intersect with each other in a tread surface view. The intersecting belt 51 (intersecting belt 52) ​​is formed by covering the belt cords 51a (belt cords 52a) with a rubber material.

[0035] The cap belt 53 is provided on the outer side in the tire radial direction of the pair of intersecting belts 51 and 52. Specifically, the cap belt 53 is provided between the intersecting belt 52 and the first reinforcing belt .

[0036] The cap belt 53 has a reinforcing cord 53a wound around the tire circumferential direction. The reinforcing cord 53a extends along the tire circumferential direction. That is, the reinforcing cord 53a is arranged so as to be substantially parallel to the tire circumferential direction, in other words, so as to be perpendicular to the tire width direction. Specifically, the angle β formed by the reinforcing cord 53a with the tire width direction is approximately 90 degrees.

[0037] The cap belt 53 can be formed by spirally winding a strip-shaped member, in which a reinforcing cord 53a is covered with a rubber material, around the tire circumferential direction. The cap belt 53 may also be called a spiral belt.

[0038] The reinforcing cord 53a is preferably formed using an organic fiber having a strength equal to or greater than a predetermined value. Specifically, the reinforcing cord 53a may be a polyamide synthetic fiber (specifically, nylon) or an aramid fiber (specifically, Kevlar), or a hybrid of both fibers.

[0039] In this embodiment, the outer end of the cap belt 53 in the tire width direction is folded back outward in the tire radial direction. Specifically, the outer end of the cap belt 53 in the tire width direction has a layer portion 53b with a folded structure folded back outward in the tire radial direction.

[0040] The layer portion 53b is formed at a position that covers the outer ends in the tire width direction of the intersecting belts 51 and 52. Note that the layer portion 53b does not necessarily have to be formed by folding back the cap belt 53, and the layer portion 53b that is separate from the cap belt 53 may be provided.

[0041] The layer portion 53b is located on the outer side in the tire width direction of the first reinforcement belt 54. It is preferable that the outer end portion in the tire width direction of the cap belt 53, i.e., the position in the tire radial direction of the layer portion 53b, coincides with the position in the tire radial direction of the first reinforcement belt 54. Specifically, it is preferable that the outer surface in the tire radial direction of the layer portion 53b and the outer surface in the tire radial direction of the first reinforcement belt 54 are flush with each other so as to avoid any steps.

[0042] The first reinforcement belt 54 has first reinforcement cords 54a. The first reinforcement cords 54a extend in the tire width direction and the tire radial direction, and are arranged at a predetermined distance apart. The first reinforcement belt 54 is formed by covering the multiple first reinforcement cords 54a with a rubber material.

[0043] In the present embodiment, the first reinforcement cord 54a is arranged so as to be substantially parallel to the tire width direction. Specifically, the angle γ formed by the first reinforcement cord 54a and the tire width direction is approximately 0 degrees.

[0044] The second reinforcement belt 55 has second reinforcement cords 55a. The second reinforcement cords 55a extend in the tire width direction and the tire radial direction, and are arranged at a predetermined distance apart. The second reinforcement belt 55 is formed by covering the second reinforcement cords 55a with a rubber material.

[0045] Although the second reinforcing belt 55 differs in size etc., it may have the same configuration as the first reinforcing belt 54. Therefore, the angle formed by the second reinforcing cord 55a with the tire width direction is also approximately 0 degrees.

[0046] The first reinforcement cord 54a and the second reinforcement cord 55a are preferably formed using a predetermined organic fiber, specifically, an organic fiber having a strength equal to or greater than a predetermined value. In this embodiment, the first reinforcement cord 54a and the second reinforcement cord 55a are formed using an aramid fiber (specifically, Kevlar).

[0047] The width of the first reinforcement belt 54 is preferably wider than the width of the second reinforcement belt 55. The outer end of the first reinforcement belt 54 in the tire width direction is preferably located near the ground contact edge of the tread 20 when the pneumatic tire 10 is set to the normal internal pressure and is subjected to a normal load.

[0048] In addition, a rubber layer such as a cover rubber (not shown) may be provided between the cap belt 53 and the first reinforcing belt 54, on the tire radial inner side of the second reinforcing belt 55, and between the plies of the two-ply carcass 40.

[0049] (3) Actions and Effects Next, the operation and effect of the pneumatic tire 10 having a sandwich structure in which the first reinforcing belt 54 and the second reinforcing belt 55 sandwich the intersecting belt 51, the intersecting belt 52, and the cap belt 53 will be described.

[0050] The first reinforcing belt 54 (which may also be called an upper reinforcing belt or an outer reinforcing belt) has the function of a buffer layer for the intersecting belts 51 and 52 and the carcass 40 from the tread 20 side (input side), and the function of sharing the tension generated in the tread 20 area together with the other belts.

[0051] The second reinforcing belt 55 (which may also be called a lower reinforcing belt or an inner reinforcing belt) has the function of suppressing deformation in the tread 20 region and the function of sharing the tension generated in the tread 20 region together with the other belts.

[0052] In tires for high-performance automobiles with excellent maneuverability, it is common to increase the rigidity of the belt layer to generate high lateral force (Fy). This allows for the generation of high cornering force (CF). However, increasing the rigidity of the belt layer increases the rigidity difference in the belt layer, which can cause cracks to propagate, and this can easily reduce durability.

[0053] The pneumatic tire 10 can achieve an improvement in CF, particularly on dry road surfaces, while suppressing a decrease in durability due to crack propagation in the belt layer caused by such a difference in rigidity.

[0054] The pneumatic tire 10 is characterized in that, compared with conventional tires of the same type, the second reinforcing belt 55 is provided between the carcass 40 and the intersecting belt (intersecting belt 51). The action and effect of such second reinforcing belt 55 will be further described.

[0055] 4 to 6 are explanatory diagrams (parts 1 to 3) of the mechanism by which the second reinforcing belt (lower reinforcing belt) suppresses deformation of the tire ground contact region. Specifically, FIG. 4 schematically shows the contact shape of a conventional pneumatic tire 10P and the road surface R of the pneumatic tire 10. Note that in FIGS. 4 to 6, the contact shape is exaggerated to facilitate understanding. The pneumatic tire 10P does not include a second reinforcing belt.

[0056] As shown in Figure 4, in the case of a pneumatic tire 10P, when the tread comes into contact with the road surface R and flexes, collapse occurs on the leading and trailing sides of the tread (see the thin arrows in the figure), and in conjunction with this collapse, the tread on the contact surface is likely to lift up (see the open arrows in the figure). In particular, this phenomenon can cause a loss of contact pressure on the outer side when mounted on a vehicle when a lateral force (cornering force (CF)) is generated. The pneumatic tire 10 is provided with a second reinforcing belt, which can effectively suppress such lifting of the tread on the contact surface.

[0057] 5, in the case of the pneumatic tire 10P, when the above-described collapse occurs, the deformation inevitably spreads in the tire width direction (see the thin arrow in the figure). Since the pneumatic tire 10 is provided with the second reinforcing belt, such deformation and lifting of the tread at the contact surface can be effectively suppressed.

[0058] 6, in the case of the pneumatic tire 10P, when a lateral force (CF) occurs, a larger load is applied to the outer tread portion when mounted on a vehicle, making the tread more likely to flex. Since the pneumatic tire 10 is provided with the second reinforcing belt, such flexing can be suppressed, and lift-up of the tread on the outer contact surface when mounted on a vehicle can also be suppressed.

[0059] Thus, according to the pneumatic tire 10, even if it is equipped with a cap belt 53 (spiral belt) and has high tensile rigidity in the tire circumferential direction or compressive rigidity in the tire width direction, by adopting a sandwich structure in which the first reinforcing belt 54 and the second reinforcing belt 55 sandwich the intersecting belts 51, 52 and cap belt 53, it is possible to prevent loss of ground contact pressure on the outside when mounted on a vehicle when a lateral force (cornering force (CF)) occurs, while effectively preventing crack propagation due to differences in rigidity in the belt layers.

[0060] In other words, the pneumatic tire 10 can suppress a decrease in durability due to crack propagation in the belt layer 50 while using a reinforcing belt (cap belt (spiral belt)) using cords extending along the tire width direction and tire radial direction.

[0061] In the present embodiment, the width of the first reinforcement belt 54 is wider than the width of the second reinforcement belt 55. Therefore, the first reinforcement belt 54 on the contact surface side effectively suppresses lifting of the tread on the contact surface, while the sandwich structure of the first reinforcement belt 54 and the second reinforcement belt 55 can suppress the progression of cracks in the belt layer 50.

[0062] In this embodiment, the first reinforcement cord 54a and the second reinforcement cord 55a are formed using organic fibers (aramid fibers) having a strength equal to or greater than a predetermined value. Such organic fibers are more resistant to tensile deformation and are lighter than steel. Therefore, the pneumatic tire 10 can be made both lightweight and strong at a high level.

[0063] (4) Other embodiments Although the embodiments have been described above, it will be obvious to those skilled in the art that the present invention is not limited to the description of the embodiments and that various modifications and improvements are possible.

[0064] For example, the second reinforcing belt 55 may be provided between the intersecting belt 51 and the intersecting belt 52. In this case as well, the second reinforcing belt 55 is provided between the carcass 40 and one of the pair of intersecting belts, and the second reinforcing belt 55 may be interpreted as being provided between the carcass and the intersecting belt.

[0065] Furthermore, although the pneumatic tire 10 includes the cap belt 53, the cap belt 53 is not essential. Alternatively, a reinforcing belt having first reinforcing cords arranged at a different angle may be provided instead of the cap belt 53. Furthermore, the outer end of the cap belt 53 in the tire width direction does not have to be folded back outward in the tire radial direction.

[0066] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure. [Explanation of symbols]

[0067] 10 Pneumatic tires 20 Tread 21 Circumferential groove 30 Tire side 40 Carcass 40a carcass cord 41 Main body 42 Folded section 42e Folded end 50 belt layers 51 Cross Belt 51a Belt cord 52 Cross Belt 52a Belt cord 53 Cap Belt 53a Reinforcement cord 53b Layer section 54 First Reinforcement Belt 54a First reinforcement cord 55 Second Reinforcement Belt 55a Second reinforcement cord 60 Bead section

Claims

1. a carcass that forms a tire skeleton; a pair of crossing belts provided on the outer side of the carcass in the tire radial direction, in which cords cross each other; A tire comprising: a first reinforcing belt provided radially outward of the intersecting belts, extending along the tire width direction and the tire radial direction, and covering a plurality of first reinforcing cords arranged at a predetermined distance from each other; a second reinforcing belt provided between the carcass and the intersecting belt, extending along the tire width direction and the tire radial direction, and covering a plurality of second reinforcing cords arranged at a predetermined distance; A tire comprising:

2. The tire according to claim 1 , wherein the width of the first reinforcing belt is greater than the width of the second reinforcing belt.

3. The tire according to claim 1 or 2, wherein the second reinforcing cord is formed from a predetermined organic fiber.

Images