Pneumatic tire

Abstract

To provide a pneumatic tire configured so that insufficiency of adhesion of a sound suppression material to an inner cavity surface of the tire can be suppressed.SOLUTION: A pneumatic tire 1 comprises a tire main body 10 and a sound suppression material 30. The sound suppression material 30 is attached by an adhesion body 40 to a tire inner cavity surface 14a of the tire main body 10. The tire main body 10 has a convex stripe part formed by pressing a bladder against the tire inner cavity surface 14a during molding. A ratio of areas of a region where the adhesion body 40 overlaps with the stripe part to areas of a region in which the adhesion body 40 is arranged is 30% or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pneumatic tire provided with a sound deadening material.

Background Art

[0002] In a pneumatic tire mounted on a vehicle, cavity resonance occurs due to the air in the tire cavity as the vehicle travels. The sound generated by the cavity resonance of the tire is transmitted to the vehicle and becomes noise in the vehicle interior. Therefore, measures against tire cavity resonance have been taken to reduce it.

[0003] Patent Document 1 discloses a pneumatic tire with a sound deadening material, which includes a toroidal pneumatic tire and a sound deadening material made of a sponge material fixed to the inner cavity surface and extending in the tire circumferential direction. On the inner cavity surface of the pneumatic tire with a sound deadening material, a plurality of ridges formed by a bladder during vulcanization are formed on the inner cavity surface. The ridges include a first ridge extending in a fixed area Y where a sound deadening tool on the inner cavity surface is fixed. Patent Document 1 describes that the fixed area consists of a smooth central area where no ridges are formed and uneven areas on both sides of this central area where only the first ridges are provided, and the central area has a width of 20% or more and less than 100% of the fixed area.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 does not describe the ratio of the bonding area of the ridges formed by the bladder. When there are ridges in the bonding area, there is a problem that the thickness of the bonding layer becomes small at the ridge part, the bonding strength decreases, and insufficient bonding occurs.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a pneumatic tire capable of suppressing insufficient adhesion of a sound deadening material to the inner cavity surface of the tire.

Means for Solving the Problems

[0007] One aspect of the present invention is a pneumatic tire. The pneumatic tire includes a tire body and a sound deadening material attached to the inner cavity surface of the tire body by an adhesive. The tire body has a convex strip portion formed by pressing a bladder against the inner cavity surface during molding, and the ratio of the area of the region where the adhesive and the strip portion overlap to the area of the region where the adhesive is disposed is 30% or less.

Effects of the Invention

[0008] According to the present invention, insufficient adhesion of the sound deadening material to the inner cavity surface of the tire can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described with reference to FIGS. 1 to 7 based on preferred embodiments. The same or equivalent components and members shown in each drawing are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, some of the members that are not important for explaining the embodiments in each drawing are omitted from the display.

[0011] (Embodiment) FIG. 1 is a cross-sectional view showing a longitudinal section of a pneumatic tire 1 including a sound-absorbing material 30 according to an embodiment. The pneumatic tire 1 includes a tire body 10, a wheel 20, a sound-absorbing material 30, and an adhesive 40. The tire body 10 contacts the ground by a tread portion 11 formed in a ring shape. Side portions 12 are continuously provided at both ends in the axial direction (the width direction of the tire) of the tread portion 11, and a bead portion 13 is formed at the end portion of the side portion 12 on the wheel 20 side.

[0012] A wheel 20 is fitted to the central portion of the tire body 10. The wheel 20 supports a rim portion 23 having a disk portion 22 extending radially and having a cylindrical shape around a hub portion 21 that connects an axle. The bead portion 13 of the tire body 10 is fitted to the rim portion 23. The tire inner cavity 14 surrounded by the tire body 10 and the rim portion 23 is filled with air.

[0013] The sound-absorbing material 30 is attached to the tire inner cavity surface 14a, which is the surface of the tread portion 11 on the tire inner cavity 14 side, by an adhesive 40. The sound-absorbing material 30 is a sponge formed of a foaming material, has a large number of pores, and is an open-cell foam having air permeability with the outside air. The sound-absorbing material 30 is made of, for example, soft urethane foam, and has a density of 60 kg / m from the viewpoint of weight balance in the pneumatic tire 1 3 The following are preferable, and the density is 40 kg / m 3The following are more preferable. Further, from the viewpoint of durability, the sound deadening material 30 preferably has a tensile strength of 30 kPa or more and a tear strength of 2.0 N / cm or more (JIS K 6400-5). The sound deadening material 30 is disposed in a ring shape on the inner cavity surface 14a of the tire by at least one member. The sound deadening material 30 may be configured by two or more members to form a ring.

[0014] FIG. 2 is a perspective view showing the appearance of the sound deadening material 30 disposed in the tire inner cavity 14. As described above, the sound deadening material 30 forms a ring shape when disposed on the inner cavity surface 14a of the tire. FIG. 2 also shows an adhesive body 40 for attaching the sound deadening material 30 to the inner cavity surface 14a of the tire. The sound deadening material 30 is attached by applying the adhesive body 40 to the inner cavity surface 14a and then pressing it against the inner cavity surface 14a.

[0015] The adhesive body 40 extends in the circumferential direction and is formed linearly, and is applied to the inner cavity surface 14a of the tire in a ring shape as a whole. In FIG. 2, three adhesive bodies 40 are provided. The number of the adhesive bodies 40 is not limited to the three shown, and two or more are sufficient. The outer peripheral surface 32 of the sound deadening material 30 is attached to the inner cavity surface 14a by the adhesive body 40, and the inner peripheral surface 31 faces the tire inner cavity 14. It is preferable to use an adhesive having a viscosity of 300 Pa·s or more and 400 Pa·s or less (Brookfield viscosity at 25°C and 20 rpm, the same hereinafter), for example, 340 Pa·s. The viscosity range of the adhesive body 40 is not limited to this example.

[0016] Before being disposed in the tire inner cavity 14, the sound deadening material 30 is in the form of an elongated plate, and is deformed into a ring shape and attached to the inner cavity surface 14a of the tire. In the state where the sound deadening material 30 is attached to the inner cavity surface 14a of the tire, both ends in the circumferential direction of the sound deadening material 30 are butted against each other, and it is preferably joined by an adhesive body 41 to prevent wear due to rubbing of both ends.

[0017] FIG. 3 is a cross-sectional view showing a longitudinal section of the tire body 10 and the adhesive body 40. On the tire inner cavity surface 14a of the tire body 10, at the time of molding, the strip portion 50 is formed by pressing a bladder against the tire inner cavity surface 14a. The strip portion 50 is formed in a convex shape. In the example shown in FIG. 3, the strip portion 50 is provided so as to extend in a direction inclined with respect to the circumferential direction, and is formed on both sides with the axial center of the tire body 10 interposed therebetween. The strip portion 50 extends outward from a position closer to the axial center of the tire body 10 and is formed up to the bead portion 13. Further, the strip portion 50 may be provided so as to extend in a direction orthogonal to the circumferential direction. The adhesive body 40 extends in the circumferential direction as described above and intersects the strip portion 50.

[0018] FIG. 4 is a cross-sectional view of the pneumatic tire 1 taken along line A-A shown in FIG. 3. In FIG. 4, cross-sections of the tire body 10, the sound deadening material 30, and the adhesive body 40 are shown. Also, the line A-A shown in FIG. 3 is a line segment extending in the circumferential direction at a position including the adhesive body 40.

[0019] As shown in FIG. 4, the adhesive body 40 is applied between the convex strip portions 50 and attaches and fixes the sound deadening material 30 to the tire inner cavity surface 14a. The thickness of the adhesive body 40 becomes thinner at the convex strip portions 50 and thicker between the strip portions 50. At the strip portions 50 where the thickness of the adhesive body 40 is thin, the adhesive strength becomes low. Therefore, the ratio of the area of the region where the adhesive body 40 and the strip portion 50 overlap to the area of the region where the adhesive body 40 is arranged is set to a predetermined value or less (30% or less).

[0020] FIG. 5 is an enlarged view of the central portion in the tire width direction in FIG. 3. Let the areas of the regions of the three adhesive bodies 40 be SA1, SA2, and SA3, respectively. The area SA1 is that of the adhesive body 40 arranged at the center in the tire width direction among the three adhesive bodies 40. In each of the three adhesive bodies 40, let the areas of the regions where the adhesive body 40 and the strip portion 50 overlap be SB1, SB2, and SB3, respectively. Since no strip portion 50 is formed at the center in the tire width direction as shown in FIG. 3, the area SB1 is 0. Note that the areas SB1, SB2, and SB3 are the sum of the areas of a plurality of regions where the adhesive body 40 and the strip portion 50 overlap over the entire circumference.

[0021] When viewed as a whole of the adhesive body 40, the ratio of the area of the region where the adhesive body 40 and the strip portion 50 overlap to the area of the region where the adhesive body 40 is disposed satisfies the following formula. 100×(SB1 + SB2 + SB3) / (SA1 + SA2 + SA3) ≤ 30 [%] ··· (1)

[0022] By disposing the adhesive body 40 so as to satisfy the formula (1), the adhesive strength by the adhesive body 40 can be set to be equal to or greater than a desired value as a whole. Further, paying attention to the portion of the adhesive body 40 that is continuous as a region, the following formula is satisfied. 100×SB1 / SA1 ≤ 30 [%] ··· (2) 100×SB2 / SA2 ≤ 30 [%] ··· (3) 100× SB3 / SA3 ≤ 30 [%] ··· (4)

[0023] By disposing the adhesive body 40 so as to satisfy the formulas (2) to (4), the adhesive strength of each part of the adhesive body 40 that is continuous as a region can be set to be equal to or greater than a desired value. Further, the ratio of the area of the region where the adhesive body 40 and the strip portion 50 overlap to the area of the region where the adhesive body 40 is disposed is preferably 20% or less. In this case, the right side of each of the formulas (1) to (4) is 20 [%].

[0024] Next, the operation of the pneumatic tire 1 will be described by paying attention to the sound-absorbing material 30 and the adhesive body 40. When a vehicle equipped with the pneumatic tire 1 is running, the cavity resonance generated in the tire cavity 14 is absorbed by the sound-absorbing material 30 and dissipated as heat energy, and the noise in the pneumatic tire 1 is reduced.

[0025] As shown in the above formula (1), for the pneumatic tire 1, when viewed as a whole of the adhesive body 40, by setting the ratio of the area of the region where the adhesive body 40 and the strip portion 50 overlap to the area of the region where the adhesive body 40 is disposed to 30% or less, insufficient adhesion can be suppressed as a whole. Further, as shown in the above formulas (2) to (4), for each portion of the adhesive body 40 that is continuous as a region, by setting the ratio of the area of the region where the adhesive body 40 and the strip portion 50 overlap to the area of the region where the adhesive body 40 is disposed to 30% or less, insufficient adhesion can be suppressed.

[0026] The pneumatic tire 1 can simplify the application process of the adhesive as the adhesive body 40 and reduce the influence on the tire weight by providing the adhesive body 40 linearly extending in the circumferential direction of the tire body 10.

[0027] The pneumatic tire 1 is formed such that the convex strip portion 50 extends in a direction intersecting the circumferential direction of the tire body 10. In the pneumatic tire 1, a plurality of convex strip portions 50 are formed in the circumferential direction of the tire body 10, and the adhesive body 40 is formed to extend in the circumferential direction, so that the adhesive body 40 and the plurality of strip portions 50 intersect. As shown in the above formula (1) or formulas (2) to (4), for the pneumatic tire 1, by setting the ratio of the area of the region where the adhesive body 40 and the strip portion 50 overlap to the area of the region where the adhesive body 40 is disposed to 30% or less, insufficient adhesion can be suppressed.

[0028] (Modification example) FIG. 6(a) and FIG. 6(b) are schematic diagrams for explaining the adhesive body 40 according to the modification example. FIG. 6(a) and FIG. 6(b) correspond to an external view looking at the tire inner cavity surface 14a from the tire inner cavity 14. In FIG. 6(a), by applying the adhesive body 40 narrowly at the center in the tire width direction and widely on both sides thereof, it is possible to suppress the sound deadening material 30 from peeling off at both side edges in the tire width direction. In FIG. 6(b), by applying the adhesive body 40 widely and substantially evenly in the tire width direction, the adhesive strength of the sound deadening material 30 can be increased.

[0029] Even with respect to the arrangement of the adhesive body 40 shown in FIGS. 6(a) and 6(b), by satisfying the above-described formula (1) or formulas (2) to (4), it is possible to suppress insufficient adhesion of the sound deadening material 30 in the pneumatic tire 1.

[0030] FIGS. 7(a) and 7(b) are schematic views for explaining an adhesive body 40 according to another modification. FIGS. 7(a) and 7(b) correspond to an external view of a desired tire inner cavity surface 14a from the tire inner cavity 14. In FIG. 7(a), the adhesive body 40 is formed in a linear shape inclined with respect to the circumferential direction. The line of the adhesive body 40 may be inclined in the same direction as the convex strip portion 50 so as not to intersect the strip portion 50, or may be inclined in the opposite direction to the convex strip portion 50 so as to intersect the strip portion 50. In FIG. 7(b), by forming the adhesive body 40 in a wavy shape that reciprocates on both sides in the tire width direction, the sound deadening material 30 can be attached without bias in the tire width direction over the entire circumference.

[0031] Even with respect to the arrangement of the adhesive body 40 shown in FIGS. 7(a) and 7(b), by satisfying the above-described formula (1) or formulas (2) to (4), it is possible to suppress insufficient adhesion of the sound deadening material 30 in the pneumatic tire 1.

[0032] Next, the features of the pneumatic tire 1 according to the embodiment and the modification will be described. The pneumatic tire 1 includes a tire body 10 and a sound deadening material 30. The sound deadening material 30 is attached to the tire inner cavity surface 14a of the tire body 10 by an adhesive body 40. The tire body 10 has a convex strip portion 50 formed by pressing a bladder against the tire inner cavity surface 14a during molding. The ratio of the area of the region where the adhesive body 40 and the strip portion 50 overlap to the area of the region where the adhesive body 40 is disposed is 30% or less. Thereby, the pneumatic tire 1 can suppress insufficient adhesion by setting the area of the region where the adhesive body 40 and the strip portion 50 overlap to a predetermined ratio or less.

[0033] The bonding body 40 is linearly formed so as to extend in the circumferential direction. Thereby, the pneumatic tire 1 can simplify the application process of the adhesive as the bonding body 40 and reduce the influence on the tire weight.

[0034] The convex strip portion 50 is formed so as to extend in a direction intersecting the circumferential direction of the tire body 10. Thereby, in the pneumatic tire 1, since the bonding body 40 is formed to extend in the circumferential direction, the bonding body 40 and the plurality of strip portions 50 intersect with each other. However, by making the area of the region where the bonding body 40 and the strip portion 50 overlap be equal to or less than a predetermined ratio, insufficient adhesion can be suppressed.

[0035] As described above, the embodiments of the present invention have been described. These embodiments are examples, and it is understood by those skilled in the art that various modifications and changes are possible within the scope of the claims of the present invention, and such modifications and changes are also within the scope of the claims of the present invention. Therefore, the description and drawings in this specification should be treated as illustrative rather than restrictive.

Explanation of Reference Numerals

[0036] 1 Pneumatic tire, 10 Tire body, 14a Tire inner cavity surface (inner cavity surface) 30 Sound deadening material, 40 Bonding body, 50 Strip portion

Claims

1. A tire body, a sound deadening material attached to the inner cavity surface of the tire body by an adhesive, comprising: the tire body having convex strip portions formed by pressing a bladder against the inner cavity surface during molding, the adhesive being provided linearly extending in the circumferential direction, the number of the adhesives being two or more, and each being arranged at intervals in the tire width direction, a pneumatic tire, characterized in that, for each of the plurality of adhesives, the ratio of the area of the region where the adhesive and the strip portion overlap to the area of the region where the adhesive is disposed is 30% or less.

2. The pneumatic tire according to claim 1, characterized in that three or more of the adhesives are provided, at least one of the adhesives being applied to a region where the central strip portion in the tire width direction is not formed, and at least one of the adhesives being applied to each of the regions where the strip portions on both sides in the tire width direction are formed.

3. The pneumatic tire according to claim 2, characterized in that the width of the adhesive applied to each of the regions where the strip portions on both sides in the tire width direction are formed is wider than the width of the adhesive applied to the region where the central strip portion in the tire width direction is not formed.

Images