Pneumatic tire

Abstract

A pneumatic tire includes a band-like sound absorbing member adhered on an inner surface of a tread portion along the tire circumferential direction. Cuts are formed on the band-like sound absorbing member mutually intersecting such that angles 1, 2 with regard to the tire width direction are within a range where 0190 or 0290. The cuts are locally disposed in a region adjacent to an end portion on a vehicle inner side of the band-like sound absorbing member. A width of the placement region of the cuts is from 10% to 80% with regard to a width of the band-like sound absorbing member.

Claims

1. A pneumatic tire, comprising: an annular-shaped tread portion extending in a tire circumferential direction; a pair of sidewall portions disposed on both sides of the tread portion; a pair of bead portions disposed on an inner side in a tire radial direction of the sidewall portions; a band-like sound absorbing member being adhered on an inner surface of the tread portion along the tire circumferential direction; and a mounting direction with regard to a vehicle being specified; wherein a plurality of cuts are formed on the band-like sound absorbing member mutually intersecting such that angles 1, 2 with regard to the tire width direction are within a range where 0190 or 0290; the cuts are locally disposed in a region adjacent to an end portion on a vehicle inner side of the band-like sound absorbing member; a width Wc of the placement region of the cuts is from 10% to 80% with regard to a width Ws of the band-like sound absorbing member; and the cuts extend continuously from the end portion across the width Wc.

2. The pneumatic tire according to claim 1, wherein an interval t of the cuts is from 5% to 90% with regard to the width Ws of the band-like sound absorbing member.

3. The pneumatic tire according to claim 2, wherein a depth d of the cuts is from 20% to 80% with regard to a thickness D of the band-like sound absorbing member.

4. The pneumatic tire according to claim 3, wherein chamfering is performed on at least an end portion positioned on a vehicle outer side of end portions in the width direction of the band-like sound absorbing member.

5. The pneumatic tire according to claim 4, wherein the band-like sound absorbing member is disposed such that a center in the width direction thereof is more on the vehicle inner side than a tire equator.

6. The pneumatic tire according to claim 5, wherein a volume of the band-like sound absorbing member is from 10% to 30% with regard to a luminal volume of the tire.

7. The pneumatic tire according to claim 6, wherein the band-like sound absorbing member has a missing portion in at least one section in the tire circumferential direction.

8. The pneumatic tire according to claim 1, wherein a depth d of the cuts is from 20% to 80% with regard to a thickness D of the band-like sound absorbing member.

9. The pneumatic tire according to claim 1, wherein chamfering is performed on at least an end portion positioned on a vehicle outer side of end portions in the width direction of the band-like sound absorbing member.

10. The pneumatic tire according to claim 1, wherein the band-like sound absorbing member is disposed such that a center in the width direction thereof is more on the vehicle inner side than a tire equator.

11. The pneumatic tire according to claim 1, wherein a volume of the band-like sound absorbing member is from 10% to 30% with regard to a luminal volume of the tire.

12. The pneumatic tire according to claim 1, wherein the band-like sound absorbing member has a missing portion in at least one section in the tire circumferential direction.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a perspective cross-sectional view of a pneumatic tire according to an embodiment of the present technology.

(2) FIG. 2 is a cross-sectional view of an equator line illustrating a pneumatic tire according to an embodiment of the present technology.

(3) FIG. 3 is a developed view illustrating a portion of a band-like sound absorbing member adhered to an inner surface of a pneumatic tire of the present technology.

(4) FIG. 4 is a cross-sectional view in a tire circumferential direction of the sound absorbing member in FIG. 3.

(5) FIG. 5 is a perspective cross-sectional view illustrating a modified example of the pneumatic tire according to the present technology.

DETAILED DESCRIPTION

(6) A configuration of the present technology will be described in detail below while referring to the attached drawings. FIG. 1 and FIG. 2 illustrate a pneumatic tire according to an embodiment of the present technology. In FIG. 1, FIG. 3, and FIG. 5, IN represents a vehicle inner side when mounted to a vehicle, and OUT represents a vehicle outer side when mounted to the vehicle.

(7) As illustrated in FIG. 1, the pneumatic tire according to the present embodiment includes an annular-shaped tread portion 1 extending in a tire circumferential direction, a pair of sidewall portions 2 disposed on both sides of the tread portion 1, and a pair of bead portions 3 disposed on an inner side in a tire radial direction of the sidewall portions 2.

(8) In the aforementioned pneumatic tire, a band-like sound absorbing member 6 is adhered via an adhesive layer 5 along the tire circumferential direction to a region of a tire inner surface 4 corresponding to the tread portion 1. The band-like sound absorbing member 6 is made of open-cell porous material and has predetermined noise absorbing properties based on the porous structure. Polyurethane foam may be used as the porous material of the band-like sound absorbing member 6. On the other hand, a double-sided adhesive tape is preferable as the adhesive layer 5.

(9) A plurality of cuts 7 extending in two mutually intersecting directions are formed on the band-like sound absorbing member 6. Herein, as illustrated in FIG. 3, angles of the cuts 7 with regard to the tire width direction are angle 1 and angle 2. In FIG. 3, Tc represents the tire circumferential direction, and the Tw represents the tire width direction. At this time, the cuts 7 are disposed such that the angles 1, 2 with regard to the tire width direction of the cut 7 are within a range where 0190 or 0290.

(10) Furthermore, the cuts 7 are locally disposed in a region adjacent to the end portion on the vehicle inner side of the band-like sound absorbing member 6. In other words, a region in the band-like sound absorbing member 6 from the end portion on the vehicle inner side of the band-like sound absorbing member 6 to a dashed-dotted line in FIG. 3 indicates a placement region of the cuts 7. A width of the placement region of the cuts 7 is set as a width Wc, and a width of the band-like sound absorbing member 6 is set as a width Ws. At this time, a condition is satisfied where the width Wc of the placement region of the cuts 7 is from 10% to 80% with regard to the width Ws of the band-like sound absorbing member 6.

(11) In the aforementioned pneumatic tire, angles 1, 2 of the cuts 7 with regard to the tire width direction are both preferably within a range of 30 to 60. Furthermore, the width Wc of the placement region of the cuts 7 is preferably from 30% to 60% with regard to the width Ws of the band-like sound absorbing member 6. Thereby, the cuts 7 of the band-like sound absorbing member 6 can open and follow deformation of the tire when the tire deflects during ground contact, relieve stress generated on the band-like sound absorbing member 6, and suppress damaging of the band-like sound absorbing member 6. As a result, the durability of the band-like sound absorbing member 6 can be improved. Furthermore, the heat dissipation area of the band-like sound absorbing member 6 increases based on the cuts 7 of the band-like sound absorbing member 6 opening during ground contact, and therefore, heat dissipation from the band-like sound absorbing member 6 can be promoted, and thus high-speed durability of the pneumatic tire can be improved.

(12) As illustrated in FIG. 3, an interval between the cuts 7 is set as interval t. At this time, the interval t of the cuts 7 is preferably from 5% to 90%, and more preferably from 15% to 30% with regard to a width Ws of the band-like sound absorbing member 6. Interval t as referred to herein is an interval between cuts 7 extending in the same direction. Furthermore, the interval of the cuts 7 on the band-like sound absorbing member 6 may be randomly disposed, but the cuts 7 are more preferably disposed at equal intervals with constant intervals t of the cuts 7 on the band-like sound absorbing member 6, from the perspective of being able to uniformly correspond tensile strain in each direction. Thereby, the cuts 7 of the band-like sound absorbing member 6 can open and follow deformation of the tire during a ground-contacting rolling motion in a condition with high tire deflection, relieve stress generated on the band-like sound absorbing member 6, and suppress damaging of the band-like sound absorbing member 6. As a result, the durability of the band-like sound absorbing member 6 can be improved.

(13) FIG. 4 is a cross-sectional view in the tire circumferential direction of the band-like sound absorbing member 6. A depth of the cuts 7 is set as a depth d, and a thickness of the band-like sound absorbing member 6 is set as a thickness D. At this time, a depth d of the cuts 7 is preferably from 20% to 80%, and more preferably from 30% to 60% with regard to a thickness D of the band-like sound absorbing member 6. Thereby, the cuts 7 of the band-like sound absorbing member 6 can open during ground contact, promote heat dissipation from the band-like sound absorbing member 6, and improve the high-speed durability of the pneumatic tire. Furthermore, damaging of the band-like sound absorbing member 6 caused by a ground-contacting rolling motion in a condition with a high tire deflection can be effectively suppressed. Herein, when the depth d of the cuts 7 is too shallow, heat dissipation from the band-like sound absorbing member 6 is reduced, and thus high-speed durability of the tire deteriorates. On the other hand, when a depth d of the cuts 7 is too deep, the band-like sound absorbing member 6 is more likely to be damaged, and wearing between the blocks of the band-like sound absorbing member 6 demarcated by the cuts 7 occurs.

(14) As illustrated in FIG. 5, chamfering can be performed on an end portion of the band-like sound absorbing member 6 in the width direction. In FIG. 5, a chamfered portion 10 is formed along the tire circumferential direction on only an end portion positioned on the vehicle outer side of the end portions of the band-like sound absorbing member in the width direction. Therefore, chamfering is preferably performed on at least the end portion positioned on the vehicle outer side of the end portions of the band-like sound absorbing member 6 in the width direction. Thereby, the durability of the band-like sound absorbing member 6 can be even further improved.

(15) In the aforementioned pneumatic tire, the band-like sound absorbing member 6 is preferably disposed such that a center thereof in the width direction is more on the vehicle inner side than the tire equator. An adhering position of the band-like sound absorbing member 6 is biased toward the vehicle inner side, and therefore, the band-like sound absorbing member 6 can be avoided from contacting a rim or tire inner wall during high deflection, and thus the durability of the band-like sound absorbing member 6 can be even further improved.

(16) In the aforementioned pneumatic tire, a volume of the band-like sound absorbing member 6 is preferably from 10% to 30% with regard to the luminal volume of a tire. Furthermore, the width Ws of the band-like sound absorbing member 6 is more preferably from 30% to 90% with regard to a tire ground contact width. Thereby, a sound absorbing effect based on the band-like sound absorbing member 6 can be even further achieved. Herein, when the volume of the band-like sound absorbing member 6 is less than 10% with regard to the luminal volume of the tire, a sound absorbing effect cannot be appropriately achieved. Furthermore, when the volume of the band-like sound absorbing member 6 exceeds 30% with regard to the luminal volume of the tire, the noise reducing effect due to the cavernous resonance phenomenon will be constant, and a further reducing effect cannot be expected.

(17) Furthermore, as illustrated in FIG. 2, the band-like sound absorbing member 6 preferably has a missing portion 9 in at least one section in the tire circumferential direction. The missing portion 9 is a portion where the band-like sound absorbing member 6 is not present on a tire circumference. By providing the missing portion 9 on the band-like sound absorbing member 6, long-term resistance is possible against expansion due to tire inflation and shear strain of an adhering surface caused by a ground-containing rolling motion, and shear strain generated on the adhering surface of the band-like sound absorbing member 6 can be effectively relieved. The missing portion 9 is preferably provided at one or 3 to 5 sections on the tire circumference. In other words, when the missing portion 9 is provided on two sections on the tire circumference, tire uniformity significantly deteriorates due to mass unbalance, and when the missing portion 9 is provided on 6 sections or more, manufacturing cost significantly increases.

(18) Note that in a case where the missing portion 9 is provided on two or more sections on the tire circumference, the band-like sound absorbing member 6 is interrupted in the tire circumferential direction. However, even in this case, for example, in a case where a plurality of the band-like sound absorbing members 6 are mutually connected by another laminate such as an adhesive layer 5 formed from a double-side adhesive tape, the band-like sound absorbing members 6 can be handled as an integral member, and therefore, the work of applying to the tire inner surface 4 can be easily performed.

(19) The present technology is further described below by examples, but the scope of the present technology is not limited to these examples.

EXAMPLES

(20) Tires of Examples 1 to 16 in which a plurality of cuts are formed so as to mutually intersect with angles 1, 2 of 45 with regard to a tire width direction on a band-like sound absorbing member, and the cuts are locally disposed in a region adjacent to an end portion in a vehicle inner side of the band-like sound absorbing member, were prepared for a pneumatic tire having a tire size of 275/35ZR20 provided with an annular-shaped tread portion extending in a tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on an inner side in a tire radial direction of the sidewall portions, where a band-like sound absorbing member is adhered on an inner surface of the tread portion along the tire circumferential direction, and a mounting direction with regard to a vehicle is specified.

(21) In Examples 1 to 16, the presence or absence of the cuts (vehicle outer side, vehicle inner side), placement region of the cuts (width We/width Ws100%), interval of the cuts (interval t/width Ws100%), depth of the cuts (depth d/thickness D100%), and presence or absence of chamfering on an end portion of the band-like sound absorbing member in the width direction are set as shown in Table 1.

(22) For comparison, tires of conventional examples were prepared without providing any cuts in the band-like sound absorbing member. Furthermore, other than the cuts being disposed in the entire region of the band-like sound absorbing member, a tire of Comparative Example 1 having the same configuration as Example 1 was prepared; and other than the cuts being locally disposed in a region adjacent to an end portion on the vehicle outer side of the band-like sound absorbing member, a tire of Comparative Example 2 having the same configuration as Example 1 was prepared. Furthermore, other than the placement regions of the cuts were set as shown in Table 1-1, tires of Comparative Example 3 and Comparative Example 4 having the same configuration as Example 1 were prepared.

(23) For the test tires, the high-speed durability with a camber angle, durability of the band-like sound absorbing member during high deflection, durability of the band-like sound absorbing member at a low temperature (20 C.), tearing of the blocks due to rubbing of the band-like sound absorbing members, and wearing of the blocks due to rubbing of the band-like sound absorbing member were evaluated by the following test methods, and the results thereof are collectively shown in Table 1.

(24) High-Speed Durability with Camber Angle:

(25) The test tires were assembled on wheels having a rim size of 209 J, and then subjected to a traveling test on a drum testing machine under testing conditions where the air pressure was 360 kPa, the load was 5 kN, and the camber angle was 4. Specifically, an initial speed was 250 km/h, the speed was increased by 10 km/h every 20 minutes, and the tire was run until failure occurred, and the reached step (speed) was measured. The results are shown in Table 1.

(26) Durability of Band-Like Sound Absorbing Member During High Strain:

(27) The test tires were assembled on wheels having a rim size of 209 J, and subjected traveling test on a drum testing machine under testing conditions where the traveling speed was 80 km/h, the air pressure was 160 kPa, the load was 8.5 kN, and the traveling distance was 3000 km, and then peeling of the adhering surface on the band-like sound absorbing member or presence/absence of damage on the band-like sound absorbing member was visually observed. The results are shown in Table 1. For the aforementioned items, cases where no dropout or damage occurred were denoted with Excellent; cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred in a portion but was not problem were denoted with Good; cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred on or less of the entire band-like sound absorbing member were denoted with Fair; and cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred on or more of the entire band-like sound absorbing member were denoted with Poor.

(28) Durability at a Low Temperature (20 C.):

(29) The test tires were assembled on wheels having a rim size of 209 J, and subjected traveling test on a drum testing machine under testing conditions where the traveling speed was 80 km/h, the air pressure was 160 kPa, the load was 5 kN, and the traveling distance was 3000 km, and then peeling of the adhering surface on the band-like sound absorbing member or presence/absence of damage on the band-like sound absorbing member was visually observed. The results are shown in Table 1. For the aforementioned items, cases where no dropout or damage occurred were denoted with Excellent; cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred in a portion but was not problem were denoted with Good; cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred on or less of the entire band-like sound absorbing member were denoted with Fair; and cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred on or more of the entire band-like sound absorbing member were denoted with Poor.

(30) Durability During J Turn Test:

(31) The test tires were mounted to a wheel with a 209 J rim size, filled at an air pressure of 180 kPa, mounted to a European car with an engine displacement of 3.5 L, run on a flat asphalt road surface in a straight line at a speed of 60 km/h, and then 10 turns of a stop test turning at a turning radius of 20 m were performed, the presence or absence of peeling on an adhering surface of the band-like sound absorbing member or damage on the band-like sound absorbing member was visually confirmed. The results are shown in Table 1. For the aforementioned items, cases where no dropout or damage occurred were denoted with Excellent; cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred in a portion but was not problem were denoted with Good; cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred on or less of the entire band-like sound absorbing member were denoted with Fair; and cases where peeling of the adhering surface or damaging of the band-like sound absorbing member occurred on or more of the entire band-like sound absorbing member were denoted with Poor.

(32) Tearing of Block Due to Rubbing Between Band-Like Sound Absorbing Members:

(33) The test tires were assembled on wheels having a rim size of 209 J, and then subjected to a traveling test on a drum testing machine under testing conditions where the air pressure was 360 kPa, the load was 5 kN, and the camber angle was 4. Specifically, the initial speed was set to 250 km/h, the speed was increased by 10 km/h every 20 minutes, and the tires were run until a speed of 310 km/h was achieved, and then tearing of the blocks due to band-like sound absorbing members rubbing together was visually confirmed. The results are shown in Table 1. For the aforementioned items, cases where no tearing of the blocks due to the band-like sound absorbing members together occurred were denoted with Excellent; cases where tearing of the blocks of the band-like sound absorbing member occurred in a portion but was not problem were denoted with Good; and cases where tearing of the blocks of the band-like sound absorbing member occurred on or less of the entire band-like sound absorbing member were denoted with Fair.

(34) Wearing of Block Due to Rubbing Between Band-Like Sound Absorbing Members:

(35) The test tires were assembled on wheels having a rim size of 209 J, and then subjected to a traveling test on a drum testing machine under testing conditions where the air pressure was 360 kPa, the load was 5 kN, and the camber angle was 4. Specifically, the initial speed was set to 250 km/h, the speed was increased by 10 km/h every 20 minutes, and the tires were run until a speed of 310 km/h was achieved, and then wearing of the blocks due to band-like sound absorbing members rubbing together was visually confirmed. The results are shown in Table 1. For the aforementioned items, cases where no wearing of the blocks due to the band-like sound absorbing members together occurred were denoted with Excellent; cases where wearing of the blocks of the band-like sound absorbing member occurred in a portion but was not problem were denoted with Good; and cases where wearing of the blocks of the band-like sound absorbing member occurred on or less of the entire band-like sound absorbing member were denoted with Fair.

(36) TABLE-US-00001 TABLE 1 Conventional Comparative Comparative Comparative Comparative example Example 1 Example 2 Example 3 Example 4 Presence/absence of cuts Vehicle outer side Absence Presence Presence Absence Absence Vehicle inner side Absence Presence Absence Presence Presence Placement region of cuts 100% 40% 5% 85% (Width Wc/width Ws 100%) Interval of cuts 4% 4% 4% 4% (Interval t/width Ws 100%) Depth of cuts 10% 10% 10% 10% (Depth d/thickness D 100%) Presence/absence of chamfering on Absence Absence Absence Absence end portion in width direction of band-like sound absorbing member High-speed durability with camber 310 350 310 320 350 angle (reached speed: km/h) Durability of During high strain Poor Good Fair Fair Good band-like sound At low temperature Poor Good Fair Fair Good absorbing member (20 C.) During J turn test Good Poor Poor Good Fair Tearing of block due to rubbing Fair Fair Fair Fair between band-like sound absorbing members Wearing of block due to rubbing Good Good Good Good between band-like sound absorbing members Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Presence/absence of cuts Vehicle outer side Absence Absence Absence Absence Absence Absence Vehicle inner side Presence Presence Presence Presence Presence Presence Placement region of cuts 40% 40% 40% 40% 40% 40% (Width Wc/width Ws 100%) Interval of cuts 4% 5% 15% 30% 45% 60% (Interval t/width Ws 100%) Depth of cuts 10% 10% 10% 10% 10% 10% (Depth d/thickness D 100%) Presence/absence of chamfering on Absence Absence Absence Absence Absence Absence end portion in width direction of band-like sound absorbing member High-speed durability with camber 350 350 350 350 340 340 angle (reached speed: km/h) Durability of During high strain Good Excellent Excellent Excellent Excellent Excellent band-like sound Allow temperature Good Good Excellent Excellent Good Good absorbing member (20 C.) During J turn test Good Good Good Good Good Good Tearing of block due to rubbing Fair Good Excellent Excellent Excellent Excellent between band-like sound absorbing members Wearing of block due to rubbing Good Good Good Good Excellent Excellent between band-like sound absorbing members Example 7 Example 8 Example 9 Example 10 Example 11 Presence/absence of cuts Vehicle outer side Absence Absence Absence Absence Absence Vehicle inner side Presence Presence Presence Presence Presence Placement region of cuts 40% 40% 40% 40% 40% (Width Wc/width Ws 100%) Interval of cuts 90% 95% 45% 45% 45% (Interval t/width Ws 100%) Depth of cuts 10% 10% 20% 30% 50% (Depth d/thickness D 100%) Presence/absence of chamfering on Absence Absence Absence Absence Absence end portion in width direction of band-like sound absorbing member High-speed durability with camber 340 330 340 350 350 angle (reached speed: km/h) Durability of During high strain Excellent Good Good Excellent Excellent band-like sound At low temperature Good Good Good Excellent Excellent absorbing member (20 C.) During J turn test Good Good Good Good Good Tearing of block due to rubbing Excellent Excellent Excellent Excellent Excellent between band-like sound absorbing members Wearing of block due to rubbing Excellent Excellent Excellent Excellent Excellent between band-like sound absorbing members Example 12 Example 13 Example 14 Example 15 Example 16 Presence/absence of cuts Vehicle outer side Absence Absence Absence Absence Absence Vehicle inner side Presence Presence Presence Presence Presence Placement region of cuts 40% 40% 40% 40% 40% (Width Wc/width Ws 100%) Interval of cuts 45% 45% 45% 45% 45% (Interval t/width Ws 100%) Depth of cuts 60% 80% 90% 20% 20% (Depth d/thickness D 100%) Presence/absence of chamfering on Absence Absence Absence Presence Presence end portion in width direction of (Outer (Inner band-like sound absorbing member side) side) High-speed durability with camber 350 350 350 340 340 angle (reached speed: km/h) Durability of During high strain Excellent Excellent Good Good Good band-like sound At low temperature Excellent Good Good Good Good absorbing member (20 C.) During J turn test Good Good Good Excellent Good Tearing of block due to rubbing Good Good Good Excellent Excellent between band-like sound absorbing members Wearing of block due to rubbing Good Good Fair Excellent Excellent between band-like sound absorbing members

(37) As seen from Table 1, the pneumatic tires of Examples 1 to 16 all simultaneously had improved high-speed durability with a camber angle, durability of various band-like sound absorbing members, tearing of the blocks due to the band-like sound absorbing members rubbing together, and wearing of the blocks due to the band-like sound absorbing members rubbing together, as compared to the Conventional Example. On the other hand, in Comparative Examples 1 to 4, the cuts of the band-like sound absorbing member are not appropriately formed, and therefore, the improving effect is reduced as compared to the Examples 1 to 16.