Pneumatic tire
11124030 · 2021-09-21
Assignee
Inventors
Cpc classification
B60C19/002
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
Provided is a pneumatic tire comprising a tread section, a side wall section, and a bead section. A tire constituent member is provided in at least the tread section, extending along the tire circumferential direction and spliced at any positions in the tire circumferential direction. A belt-shaped sound-absorbing member is adhered to a region corresponding to the tread section in the tire inner surface, along the tire circumferential direction and via an adhesive layer. The sound-absorbing member is arranged intermittently along the tire circumferential direction. Sections where the sound-absorbing member is missing are arranged at positions corresponding to the splice portions of the tire constituent member and the sound-absorbing member is arranged so as to not overlap the splice portions.
Claims
1. A pneumatic tire comprising: a tread section forming an annular shape extending in a tire circumferential direction; a pair of side wall sections arranged on both sides of the tread section; and a pair of bead sections arranged inside in a tire radial direction of the side wall sections, wherein a tire constituent member is provided in at least the tread section, extending in the tire circumferential direction and spliced at any position in the tire circumferential direction, a belt-shaped sound-absorbing member is adhered to a region corresponding to the tread section in a tire inner surface, along the tire circumferential direction and via an adhesive layer, the sound-absorbing member is formed of a porous material having open cells, the sound-absorbing member is arranged intermittently along the tire circumferential direction so as to be exposed to the tire inner surface, sections where the sound-absorbing member is missing are arranged at positions corresponding to a splice portion of the tire constituent member, and the sound-absorbing member is arranged so as to not overlap the splice portion.
2. The pneumatic tire according to claim 1, wherein the tire constituent member is an inner liner layer and the sections where the sound-absorbing member is missing are arranged at the positions corresponding to the splice portion of the inner liner layer.
3. The pneumatic tire according to claim 1, wherein the tire constituent member is a carcass layer and the sections where the sound-absorbing member is missing are arranged at the positions corresponding to the splice portion of the carcass layer.
4. The pneumatic tire according to claim 1, wherein the tire constituent member is a carcass layer and an inner liner layer, and the sections where the sound-absorbing member is missing are each arranged at the positions corresponding to the splice portion of the carcass layer and the inner liner layer.
5. The pneumatic tire according to claim 4, wherein, when a splice-peripheral region is defined to be 20 mm or less from the splice portion in the tire circumferential direction and splice-adjacent regions are defined to be from 20 to 120 mm from the splice portion in the tire circumferential direction, end sections of the sound-absorbing member in the tire circumferential direction are excluded from the splice-peripheral region to be arranged inside the splice-adjacent regions.
6. The pneumatic tire according to claim 5, wherein the sound-absorbing member is a single sound-absorbing member extending in the tire circumferential direction and has a uniform thickness in at least a range corresponding to the surface to which belt-shaped sound-absorbing member is adhered in a cross-section orthogonal to a longitudinal direction of the sound-absorbing member, and a cross-sectional shape is constant in the longitudinal direction.
7. The pneumatic tire according to claim 6, wherein a ratio of a volume of the sound-absorbing member with respect to a volume of a cavity formed inside the tire during rim assembly is greater than 20%.
8. The pneumatic tire according to claim 7, wherein a hardness of the sound-absorbing member is from 60 to 170 N and a tensile strength of the sound-absorbing member is from 60 to 180 kPa.
9. The pneumatic tire according to claim 8, wherein the adhesive layer is formed of double-sided adhesive tape and a peeling adhesive strength of the adhesive layer is in a range of 8 to 40 N/20 mm.
10. The pneumatic tire according to claim 9, wherein the porous material is a foamed polyurethane.
11. The pneumatic tire according to claim 1, wherein, when a splice-peripheral region is defined to be 20 mm or less from the splice portion in the tire circumferential direction and splice-adjacent regions are defined to be from 20 to 120 mm from the splice portion in the tire circumferential direction, end sections of the sound-absorbing member in the tire circumferential direction are excluded from the splice-peripheral region to be arranged inside the splice-adjacent regions.
12. The pneumatic tire according to claim 1, wherein the sound-absorbing member is a single sound-absorbing member extending in the tire circumferential direction and has a uniform thickness in at least a range corresponding to the surface to which belt-shaped sound-absorbing member is adhered in a cross-section orthogonal to a longitudinal direction of the sound-absorbing member, and a cross-sectional shape is constant in the longitudinal direction.
13. The pneumatic tire according to claim 1, wherein a hardness of the sound-absorbing member is from 60 to 170 N and a tensile strength of the sound-absorbing member is from 60 to 180 kPa.
14. The pneumatic tire according to claim 1, wherein the adhesive layer is formed of double-sided adhesive tape and a peeling adhesive strength of the adhesive layer is in a range of 8 to 40 N/20 mm.
15. The pneumatic tire according to claim 1, wherein the porous material is a foamed polyurethane.
16. The pneumatic tire according to claim 1, wherein: the sound absorbing member extends across a majority of the tread section and extends beneath all of circumferential main grooves in the tread section.
17. The pneumatic tire according to claim 1, wherein: the tire constituent member includes a carcass layer and an inner liner layer; and the splice portions of the inner liner layer and the carcass layer are offset from one another.
18. The pneumatic tire according to claim 1, wherein: the tire constituent member includes a carcass layer and an inner liner layer; and ends of the sound-absorbing member on either side of the splice portion of the inner liner layer and the carcass layer are spaced differently from one another.
19. The pneumatic tire according to claim 1, wherein a ratio of a volume of the sound-absorbing member with respect to a volume of a cavity formed inside the tire during rim assembly is greater than 20%.
20. The pneumatic tire according to claim 1, wherein a ratio of a volume of the sound-absorbing member with respect to a volume of a cavity formed inside the tire during rim assembly is greater than 22%.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DETAILED DESCRIPTION
(10) A detailed description of the configuration of the present technology is given below, with reference to the accompanying drawings.
(11) As illustrated in
(12) On the other hand, a plurality of belt layers 15 are embedded in the outer peripheral side of the carcass layer 11 in the tread section 1. These belt layers 15 include a plurality of reinforcing cords inclined with respect to the tire circumferential direction and arranged such that the reinforcing cords intersect with each other between the layers. In the belt layers 15, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set to, for example, a range of 10 to 40°. Steel cords are preferably used as the reinforcing cords of the belt layers 15. For the purpose of improving the high-speed durability, at least one belt cover layer 16 in which the reinforcing cords line up at an angle of, for example, 5° or less with respect to the tire circumferential direction is arranged on the outer peripheral side of the belt layers 15. Organic fiber cords of nylon, aramid, or the like are preferably used as the reinforcing cords of the belt cover layer 16.
(13) In a region in the pneumatic tire described above corresponding to the tread section 1 of the tire inner surface 4, a belt-shaped sound-absorbing member 6 is adhered along the tire circumferential direction via an adhesive layer 5. The sound-absorbing member 6 is formed of a porous material having open cells and has predetermined acoustic absorption characteristics based on the porous structure thereof. A foamed polyurethane may be used as the porous material of the sound-absorbing member 6. On the other hand, a paste-like adhesive or double-sided adhesive tape can be used as the adhesive layer 5.
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(18) In the pneumatic tire described above, when the belt-shaped sound-absorbing member 6 is adhered to a region corresponding to the tread section 1 of the tire inner surface 4 in the tire circumferential direction via the adhesive layer 5, the sound-absorbing member 6 is arranged intermittently along the tire circumferential direction, the missing section 6A of the sound-absorbing member 6 is arranged at a position corresponding to the splice portions 11A and 14A of the tire constituent members such as the carcass layer 11 and the inner liner layer 14, the sound-absorbing member 6 is arranged so as to not overlap the splice portions 11A and 14A, thus it is possible to avoid deterioration of the initial adhesion and the adhesion durability of the sound-absorbing member 6 caused by differences in level (unevenness) in the splice portions 11A and 14A. As a result, it is possible to avoid a reduction in the fixing strength of the sound-absorbing member 6 and to suppress peeling of the sound-absorbing member 6.
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(21) In the pneumatic tire described above, a single sound-absorbing member 6 extends in the tire circumferential direction and it is preferable that the sound-absorbing member 6 have a uniform thickness at least in a range corresponding to the adhering surface in a cross-section orthogonal to a longitudinal direction, and a cross-sectional shape is constant in the longitudinal direction. In particular, it is preferable that the cross-sectional shape of the cross-section orthogonal to the longitudinal direction of the sound-absorbing member 6 be a rectangular shape (including a square shape); however, in some cases, it is also possible for the cross-sectional shape to be a reverse trapezoid in which the adhering surface sides are narrowed. As a result, it is possible to maximize the content of the sound-absorbing member 6 per adhesive surface area and obtain an excellent noise reduction effect. In addition, the manufacturing costs are also low because the sound-absorbing member 6 having this shape is easily processed.
(22) A cavity 7 is formed between the tire inner surface 4 and the rim when rim-assembling the pneumatic tire described above and the ratio of the volume of the sound-absorbing member 6 with respect to the volume of the cavity 7 is preferably greater than 20%. An excellent noise reduction effect can be obtained by increasing the volume of the sound-absorbing member 6 in this manner and a favorable adhesion state can be preserved for extended periods of time even with a large amount of sound-absorbing member 6. Here, the width of the sound-absorbing member 6 is preferably in a range of 30 to 90% of the tire ground contact width. In addition, the sound-absorbing member 6 is preferably a non-annular shape.
(23) The hardness (JIS-K6400-2) of the sound-absorbing member 6 is preferably from 60 to 170 N and the tensile strength (JIS-K6400-5) of the sound-absorbing member 6 is preferably from 60 to 180 kPa. The sound-absorbing member 6 having these properties is excellent in durability against shear strain. When the hardness or tensile strength of the sound-absorbing member 6 is excessively small, the durability of the sound-absorbing member 6 is reduced. In particular, the hardness of the sound-absorbing member 6 is preferably from 70 to 160 N and more preferably from 80 to 140 N. In addition, the tensile strength of the sound-absorbing member 6 is preferably set to from 75 to 165 kPa and more preferably from 90 to 150 kPa.
(24) The peeling adhesive strength (Japanese Industrial Standard JIS-Z0237: 2009) of the adhesive layer 5 is preferably in a range of 8 to 40 N/20 mm. As a result, it is possible to easily perform the sound-absorbing member 6 attachment operation and a disassembling operation at the time of tire disposal while maintaining excellent fixing strength in the sound-absorbing member 6. That is, when the peeling strength of the adhesive layer 5 is excessively weak, the fixed state of the sound-absorbing member 6 is unstable, in contrast, the peeling strength of the adhesive layer 5 is excessively strong, it is difficult to change the attachment position in the attachment operation of the sound-absorbing member 6, and it is difficult to peel the sound-absorbing member 6 at the time of tire disposal. In particular, the peeling adhesive strength of the adhesive layer 5 is preferably from 9 to 30 N/20 mm and more preferably from 10 to 25 N/20 mm.
EXAMPLES
(25) Based on pneumatic tires with a tire size of 195/65R15 including a tread section forming an annular shape extending in a tire circumferential direction, a pair of side wall sections arranged on both sides of the tread section, and a pair of bead sections arranged inside in a tire radial direction of the side wall sections, in which a belt-shaped sound-absorbing member is adhered to a region corresponding to the tread section in the tire inner surface, along the tire circumferential direction and via an adhesive layer, tires of Comparative Example 1 and Working Examples 1 to 3 were manufactured in which the arrangement state of the sound-absorbing member was different.
(26) In Comparative Example 1, the belt-shaped sound-absorbing member was arranged over the entire region on the tire circumference without providing a missing section.
(27) In Working Example 1, the sound-absorbing member was arranged intermittently in the tire circumferential direction as in
(28) In Working Example 2, the sound-absorbing member was arranged intermittently in the tire circumferential direction as in
(29) In Working Example 3, the sound-absorbing member was arranged intermittently in the tire circumferential direction as in
(30) Comparative Example 1 and Working Examples 1 to 3 had the following in common. The cross-sectional shape in the cross-section orthogonal to the longitudinal direction of the sound-absorbing member was set as a rectangle and the cross-sectional shape thereof was constant along the tire circumferential direction. The ratio of the volume of the sound-absorbing member with respect to the volume of the cavity formed inside the tire during rim assembly was set to 25%. The hardness of the sound-absorbing member was set to 91 N and the tensile strength of the sound-absorbing member was set to 132 kPa. The peeling adhesive strength of the adhesive layer was set to 16 N/20 mm. In addition, in Working Examples 1 to 3, the end sections of the sound-absorbing member in the tire circumferential direction were arranged at positions separated by 50 mm from the splice portion in the tire circumferential direction.
(31) After assembling each of the pneumatic tires of Comparative Example 1 and Working Examples 1 to 3 on wheels with a rim size 15×6JJ and carrying out running tests 100 times in a drum testing machine under conditions of an air pressure of 150 kPa, a load of 5 kN, and a speed of 100 km/h, the presence or absence of adhesion peeling in the sound-absorbing member was visually confirmed. In addition, as the index of the adhesion peeling resistance, running tests were carried out in a drum testing machine under the same running conditions as described above, the presence or absence of adhesion peeling of the sound-absorbing member every ten hours was confirmed, and the running distance until the adhesion peeling is generated was determined. Evaluation results were expressed as index values, Comparative Example 1 being assigned an index value of 100. Larger index values indicate superior adhesion peeling resistance. The results are shown in Table 1.
(32) TABLE-US-00001 TABLE 1 Comparative Working Working Working Example 1 Example 1 Example 2 Example 3 Presence or absence of Absent Present Present Present missing section Arrangement of the — FIG. 3 FIG. 5 FIG. 7 missing section in the circumferential direction Presence or absence of Present Absent Absent Absent adhesion peeling of sound-absorbing member Adhesion peeling 100 110 110 115 resistance
(33) As shown in Table 1, in the tire of Comparative Example 1, adhesion peeling of the sound-absorbing member was remarkably generated after carrying out the running tests for 100 hours; however, in the tires of Working Examples 1 to 3, adhesion peeling of the sound-absorbing member after the running tests for 100 hours was not seen at all.
(34) Next, tires of Working Examples 4 to 10 were prepared having the same structure as Example 1 except that the hardness of the sound-absorbing member, the tensile strength of the sound-absorbing member, the peeling adhesive strength of the adhesive layer, and the distance in the tire circumferential direction between the end sections of the sound-absorbing member in the tire circumferential direction and the splice portion were differentiated.
(35) For the tires of Working Examples 4 to 10, using the same methods as described above, the presence or absence of the adhesion peeling of the sound-absorbing member and the adhesion peeling resistance were evaluated after carrying out the running tests for 100 hours. The results are shown in Table 2.
(36) TABLE-US-00002 TABLE 2 Working Working Working Working Working Working Working Example Example Example Example Example Example Example 4 5 6 7 8 9 10 Presence or absence Present Present Present Present Present Present Present of missing section Arrangement FIG 3 FIG. 3 FIG 3 FIG 3 FIG 3 FIG. 3 FIG. 3 of the missing section in the circumferential direction Hardness of the 60 170 91 91 91 91 91 sound-absorbing member (N) Tensile strength 60 180 132 132 132 132 132 (kPa) of the sound-absorbing member Peel adhesion 16 16 8 40 16 16 16 strength of the adhesive layer (N/20 mm) Distance (mm) 50 50 50 50 10 20 120 between end sections and splice portion of the sound-absorbing member Presence or absence Absent Absent Absent Absent Absent Absent Absent of adhesion peeling of sound-absorbing member Adhesion peeling 110 110 105 120 105 110 110 resistance
(37) As shown in Table 2, in the tires of Working Examples 4 to 7 in which the hardness of the sound-absorbing member, the tensile strength of the sound-absorbing member, the peeling adhesive strength of the adhesive layer were changed, in the same manner as Example 1, adhesion peeling of the sound-absorbing member was not seen at all after carrying out the running tests for 100 hours. In addition, as is clear from a comparison of Example 1 and Working Examples 8 to 10, it is determined that it is possible to obtain a favorable adhesion peeling resistance by appropriately adjusting the distance in the tire circumferential direction between the end sections of the sound-absorbing member in the tire circumferential direction and the splice portion. However, when the distance between the end sections of the sound-absorbing member and the splice portion is excessively increased, the noise reduction effect is reduced in accordance with a reduction in the sound-absorbing member.