Pneumatic tire
11214101 · 2022-01-04
Assignee
Inventors
Cpc classification
B60C19/002
PERFORMING OPERATIONS; TRANSPORTING
B32B3/28
PERFORMING OPERATIONS; TRANSPORTING
B60C1/00
PERFORMING OPERATIONS; TRANSPORTING
B29D30/0061
PERFORMING OPERATIONS; TRANSPORTING
B32B2307/54
PERFORMING OPERATIONS; TRANSPORTING
B60C15/00
PERFORMING OPERATIONS; TRANSPORTING
B32B5/18
PERFORMING OPERATIONS; TRANSPORTING
B32B7/12
PERFORMING OPERATIONS; TRANSPORTING
B60C5/00
PERFORMING OPERATIONS; TRANSPORTING
B60C11/00
PERFORMING OPERATIONS; TRANSPORTING
B60C13/00
PERFORMING OPERATIONS; TRANSPORTING
International classification
B60C19/00
PERFORMING OPERATIONS; TRANSPORTING
B32B3/28
PERFORMING OPERATIONS; TRANSPORTING
B60C5/00
PERFORMING OPERATIONS; TRANSPORTING
B32B3/08
PERFORMING OPERATIONS; TRANSPORTING
B32B5/18
PERFORMING OPERATIONS; TRANSPORTING
B32B7/12
PERFORMING OPERATIONS; TRANSPORTING
B29D30/00
PERFORMING OPERATIONS; TRANSPORTING
B60C13/00
PERFORMING OPERATIONS; TRANSPORTING
B60C11/00
PERFORMING OPERATIONS; TRANSPORTING
B60C1/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A pneumatic tire according to the present technology is a pneumatic tire provided with a tread section, sidewall sections, and bead sections, a belt-shaped sound-absorbing member being bonded via an adhesive layer to an inner surface of the tire in a region corresponding to the tread section along the circumferential direction of the tire, wherein a bonding surface of the sound-absorbing member is provided with a bonded region that is bonded to the inner surface of the tire and an unbonded region that is not bonded to the inner surface of the tire, and the bonded region is divided by the unbonded region into a plurality of divisions along the circumferential direction of the tire.
Claims
1. A pneumatic tire provided with a ring-shaped tread section that extends in a circumferential direction of the tire, a pair of side wall sections disposed on both sides of the tread section, and a pair of bead sections disposed to the inside of the side wall sections with respect to a radial direction of the tire, a belt-shaped sound-absorbing member being bonded via an adhesive layer to an inner surface of the tire in a region corresponding to the tread section along the circumferential direction of the tire, the tire being characterized in that a bonding surface of the sound-absorbing member is provided with a bonded region in which the sound-absorbing member is bonded to the inner surface of the tire and at least one unbonded region in which the sound-absorbing member is not bonded to the inner surface of the tire, and the bonded region is divided by the at least one unbonded region into a plurality of divisions along the circumferential direction of the tire, wherein the bonding surface of the sound absorbing member is in contact with the inner surface of the tire at the at least one unbonded region and wherein a profile of the at least one unbonded region and the bonded region of the bonding surface matches a profile of an inner surface of the sound-absorbing member opposite the bonding surface; wherein: a volume of the sound-absorbing member is more than 20% of a volume of a cavity formed within the tire when the tire is mounted on a rim; the sound-absorbing member comprises at least one cut-out section in at least one location along the circumferential direction of the tire; and the at least one cut-out section and the at least one unbonded region are disposed at intervals around the circumferential direction of the tire, and, defining n as a total number of cut-out sections and unbonded regions, a reference angle α as 360°/n, and a tolerance angle β as 90°/n, an angle θ at which the at least one cut-out section and the at least one unbonded region are disposed satisfies a relationship α−β≥θ≥α+β.
2. The pneumatic tire according to claim 1, wherein the at least one unbonded region has a shape that overlaps an imaginary straight line orthogonal to the circumferential direction of the tire along an entire width of the sound-absorbing member.
3. The pneumatic tire according to claim 2, wherein the bonded region is divided by the at least one unbonded region into a plurality of divisions along a widthwise direction of the tire.
4. The pneumatic tire according to claim 3, wherein the sound-absorbing member is constituted by a single sound-absorbing member extending in the circumferential direction of the tire, the sound-absorbing member being of uniform thickness at least within a range corresponding to the bonding surface of the sound-absorbing member as seen in a cross-section orthogonal to a lengthwise direction thereof, and having a constant cross-sectional shape along the lengthwise direction.
5. The pneumatic tire according to claim 1, wherein the bonded region is divided by the at least one unbonded region into a plurality of divisions along a widthwise direction of the tire.
6. The pneumatic tire according to claim 1, wherein the sound-absorbing member is constituted by a single sound-absorbing member extending in the circumferential direction of the tire, the sound-absorbing member being of uniform thickness at least within a range corresponding to the bonding surface of the sound-absorbing member as seen in a cross-section orthogonal to a lengthwise direction thereof, and having a constant cross-sectional shape along the lengthwise direction.
7. The pneumatic tire according to claim 1, wherein the sound-absorbing member has a hardness of 60 to 170 N, and a tensile strength of 60 to 180 kPa.
8. The pneumatic tire according to claim 7, wherein the adhesive layer is constituted by double-sided adhesive tape, and has a peeling adhesive strength in a range of 8 to 40 N/20 mm.
9. The pneumatic tire according to claim 8, wherein the sound-absorbing member is constituted by a porous material containing open cells.
10. The pneumatic tire according to claim 9, wherein the porous material is polyurethane foam.
11. The pneumatic tire according to claim 1, wherein the adhesive layer is constituted by double-sided adhesive tape, and has a peeling adhesive strength in a range of 8 to 40 N/20 mm.
12. The pneumatic tire according to claim 1, wherein the sound-absorbing member is constituted by a porous material containing open cells.
13. The pneumatic tire according to claim 12, wherein the porous material is polyurethane foam.
14. The pneumatic tire according to claim 1, wherein a distance between divisions of the bonded regions by the at least one unbonded region is from 10 to 80 mm.
15. A pneumatic tire provided with a ring-shaped tread section that extends in a circumferential direction of the tire, a pair of side wall sections disposed on both sides of the tread section, and a pair of bead sections disposed to the inside of the side wall sections with respect to a radial direction of the tire, a belt-shaped sound-absorbing member being bonded via an adhesive layer to an inner surface of the tire in a region corresponding to the tread section along the circumferential direction of the tire, the tire being characterized in that a bonding surface of the sound-absorbing member is provided with a bonded region in which the sound-absorbing member is bonded to the inner surface of the tire and at least one unbonded region in which the sound-absorbing member is not bonded to the inner surface of the tire, and the bonded region is divided by the at least one unbonded region into a plurality of divisions along the circumferential direction of the tire, wherein the bonding surface of the sound absorbing member is in contact with the inner surface of the tire at the at least one unbonded region and wherein a profile of the at least one unbonded region and the bonded region of the bonding surface matches a profile of an inner surface of the sound-absorbing member opposite the bonding surface; wherein the sound-absorbing member comprises at least one cut-out section in at least one location along the circumferential direction of the tire; and at least one cut-out section and at least one unbonded region are disposed at intervals around the circumferential direction of the tire, and, defining n as a total number of cut-out sections and unbonded regions, a reference angle α as 360°/n, and a tolerance angle β as 90°/n, an angle θ at which the at least one cut-out section and the at least unbonded region are disposed satisfies a relationship α−β≥θ≥α+θ.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
DETAILED DESCRIPTION
(13) A detailed description of the configuration of the present technology is given below, with reference to the accompanying drawings.
(14) In the pneumatic tire described above, a belt-shaped sound-absorbing member 6 is bonded via an adhesive layer 5 to the tire inner surface 4 in a region corresponding to the tread section 1 along the circumferential direction of the tire. The sound-absorbing member 6 is constituted by a porous material comprising open cells, and has specific sound-absorbing characteristics based on its porous structure. Polyurethane foam is preferably used as the porous material constituting the sound-absorbing member 6. Meanwhile, a paste-like adhesive or double-sided adhesive tape can be used for the adhesive layer 5.
(15)
(16) In the pneumatic tire described above, the belt-shaped sound-absorbing member 6 is bonded via the adhesive layer 5 to the inner surface 4 of the tire in a region corresponding to the tread section 1 along the circumferential direction of the tire, the bonding surface of the sound-absorbing member 6 is provided with a bonded region 6A and an unbonded region 6B, and the bonded region 6A is divided by the unbonded region 6B into a plurality of divisions along the circumferential direction of the tire, making it possible to mitigate shear strain generated in the bonding surface of the sound-absorbing member by radial growth due to inflation-induced swelling or centrifugal force when traveling at high speed or by deformation of the tread section when in contact with the ground. Specifically, shear strain caused by changes in the circumferential length of the tread section 1 increase when the length of the bonded region 6A along the circumferential direction of the tire increases; however, dividing the bonded region 6A by the unbonded region 6B into a plurality of divisions along the circumferential direction of the tire allows this shear strain to be reduced. As a result, it is possible to suppress peeling of the sound-absorbing member 6 and maintain the noise-reducing effects of the sound-absorbing member 6 over extended periods of time.
(17) It is necessary that an unbonded region 6B be provided at at least one location in the sound-absorbing member 6; it is also acceptable to provide unbonded regions at multiple locations along the lengthwise direction of the sound-absorbing member 6. The distance D along the tire circumferential direction between divisions of the bonded region 6A divided by the unbonded regions 6B is preferably set in a range of 10 to 80 mm. If the distance D is less than 10 mm, shear-strain-mitigating effects will be reduced; conversely, if the distance exceeds 80 mm, the sound-absorbing member 6 will move easily, which is a factor negatively affecting the durability thereof.
(18)
(19)
(20)
(21) In the pneumatic tire described above, it is preferable that a single sound-absorbing member 6 extend in the circumferential direction of the tire, the sound-absorbing member 6 being of uniform thickness at least within a range corresponding to the bonding surface of the sound-absorbing member as seen in a cross-section orthogonal to the lengthwise direction thereof, and having a constant cross-sectional shape along its lengthwise direction. In particular, it is preferable that the sound-absorbing member 6 have a rectangular (including square) cross-sectional shape in a cross-section orthogonal to the lengthwise direction thereof; however, in some cases, an inverted trapezoid shape in which the bonding surface side is narrower in width may also be possible. This allows the volume of sound-absorbing member 6 per unit of bonded area to be maximized, thereby yielding superior noise-reducing effects. In addition, a sound-absorbing member 6 having such a shape is easy to machine, thereby reducing manufacturing costs.
(22) When the pneumatic tire described above is mounted on a rim, a cavity 7 is formed between the entire inner surface 4 and the rim; the volume of the sound-absorbing member 6 is preferably more than 20% of the volume of the cavity 7. Increasing the volume of the sound-absorbing member 6 in this way allows superior noise-reducing effects to be obtained, and allows a satisfactory bonded state to be maintained over long periods of time even when a large sound-absorbing member 6 is used. The width of the sound-absorbing member 6 is preferably in a range of 30 to 90% of the tire ground contact width.
(23) It is preferable that the sound-absorbing member 6 have a hardness (DIS-K 6400-2) of 60 to 170 N, and a tensile strength (JIS-K 6400-5) of 60 to 180 kPa. Sound-absorbing member 6 having such physical properties will exhibit superior durability against shear strain. If the hardness or tensile strength of the sound-absorbing member 6 is too low, the durability of the sound-absorbing member 6 will be reduced. In particular, the hardness of the sound-absorbing member 6 is preferably from 70 to 160 N, more preferably from 80 to 140 N. The tensile strength of the sound-absorbing member 6 is preferably from 75 to 165 kPa, more preferably from 90 to 150 kPa.
(24) It is preferable that the sound-absorbing member 6 comprise a cut-out section 8 at least one location along the circumferential direction of the tire, as illustrated in
(25) Providing cut-out sections 8 at two or more locations around the circumference of the tire causes the sound-absorbing member 6 to be discontinuous along the circumferential direction of the tire; however, even in such cases, the individual sound-absorbing members 6 can be handled as a single intact member by, for example, connecting the multiple sound-absorbing members 6 to each other using another laminate such as an adhesive layer 5 of double-sided adhesive tape, thereby facilitating the process of bonding the sound-absorbing member 6 to the inner surface of the tire.
(26)
(27) In the embodiment illustrated in
(28) cut-out sections 8 and unbonded regions 6B at intervals around the circumferential direction of the tire, it is preferable that, defining n as the total number of cut-out sections 8 and unbonded regions 6B, a reference angle α as 360°/n, and a tolerance angle β as 90°/n, the angle θ at which the cut-out sections 8 and the unbonded regions 6B are actually disposed satisfy the relationship α−β≤θ≤α+β. For example, θ=180°±45° in the embodiment illustrated in
(29) It is preferable that the adhesive layer 5 have a peeling adhesive strength (JIS-Z 0237:2009) in a range of 8 to 40 N/20 mm. This facilitates the processes of bonding the sound-absorbing member 6 and removing the sound-absorbing member when the tire is being disposed of while maintaining satisfactory anchoring strength on the part of the sound-absorbing member 6. Specifically, if the peel strength of the adhesive layer 5 is too low, the anchoring state of the sound-absorbing member 6 will become unstable; conversely, if the peel strength of the adhesive layer 5 is too great, it will be difficult to alter the bonding position during the process of bonding the sound-absorbing member 6, and to remove the sound-absorbing member 6 when disposing of the tire. In particular, the peeling adhesive strength of the adhesive layer 5 is preferably from 9 to 30 N/20 mm, more preferably 10 to 25 N/20 mm.
(30) The pneumatic tire described above comprises tire component members such as a carcass layer and an inner liner layer; these tire component members comprise spliced sections extending in the widthwise direction of the tire that are formed by splicing the tire circumferential directional ends of belt-shaped members to each other. If such tire constituent members are present, the spliced sections thereof are preferably disposed in the unbonded region 6B of the sound-absorbing member 6. More specifically, the spliced sections are preferably disposed along the imaginary straight lines L as illustrated in
EXAMPLES
(31) Tires according to a Comparative Example 1 and Working Examples 1 to 3 constituted by size 215/45R17 pneumatic tires provided with a ring-shaped tread section that extends in a circumferential direction of the tire, a pair of side wall sections disposed on both sides of the tread section, and a pair of bead sections disposed to the inside of the side wall sections with respect to a radial direction of the tire, a belt-shaped sound-absorbing member being bonded via an adhesive layer to an inner surface of the tire in a region corresponding to the tread section along the circumferential direction of the tire were prepared, with the sound-absorbing member being bonded in different manners in the various tires.
(32) In Comparative Example 1, a cut-out section was provided at one location in the belt-shaped sound-absorbing member along the circumferential direction of the tire, and the entire bonding surface of the sound-absorbing member constituted a bonded region.
(33) In Working Example 1, a cut-out section was provided in the belt-shaped sound-absorbing member at one location along the circumferential direction of the tire, and, as illustrated in
(34) In Working Example 2, a cut-out section was provided in the belt-shaped sound-absorbing member at one location along the circumferential direction of the tire, and, as illustrated in
(35) In Working Example 3, a cut-out section was provided in the belt-shaped sound-absorbing member at one location along the circumferential direction of the tire, and, as illustrated in
(36) Comparative Example 1 and Working Examples 1 to 3 shared the following features. The sound-absorbing member had a rectangular cross-sectional shape as seen in a cross-section orthogonal to the lengthwise direction thereof, and the cross-sectional shape was constant along the tire circumferential direction. The volume of the sound-absorbing member was 30% of the volume of the cavity formed within the tire when mounted on a rim. The sound-absorbing member had a hardness of 80 N and a tensile strength of 90 kPa. The adhesive layer had a peeling adhesive strength of 16 N/20 mm.
(37) The pneumatic tires according to Comparative Example 1 and Working Examples 1 to 3 were mounted on wheels having rim sizes of 17×7 JJ, and subjected to a 100-hour running test on a drum tester at an air pressure of 150 kPa, a load of 5 kN, and a speed of 150 km/h, after which the presence or lack of peeling of the sound-absorbing member was visually confirmed. In order to obtain an index of peeling resistance, a running test was performed using a drum tester under similar conditions, the presence or lack of sound-absorbing member peeling was confirmed every 10 hours, and the running distance until peeling occurred was measured. Peeling resistance evaluation results were expressed as index vales, Comparative Example 1 being assigned an index value of 100. Larger index values indicate superior peeling resistance. Results are shown in table 1.
(38) TABLE-US-00001 TABLE 1 Comparative Working Working Working Example 1 Example 1 Example 2 Example 3 Unbonded region present? No Yes Yes Yes Disposition of unbonded region — FIG. 2 FIG. 2 FIG. 8 along circumferential direction Plan-view shape of unbonded — FIG. 3 FIG. 6 FIG. 5 region Angle θ at which cut-out — 180 180 120 section(s) and unbonded region(s) are disposed Peeling of sound-absorbing Yes No No No member present? Peeling resistance 100 120 130 130
(39) As shown in table 1, the tire of Comparative Example 1 exhibited dramatic peeling of the sound-absorbing member following the 100-hour running test, whereas absolutely no peeling of the sound-absorbing member was observed after the 100-hour running test in the tires of Working Examples 1 to 3.
(40) Next, tires according to Working Examples 4 to 11 having structures identical to that of Working Example 1 or 3, except for having different sound-absorbing member hardnesses, sound-absorbing member tensile strengths, adhesive layer peeling adhesive strengths, and cut-out section/unbonded region disposition angles θ, were prepared.
(41) The tires according to Working Examples 4 to 11 were evaluated for the presence or lack of sound-absorbing member peeling and peeling resistance following a 100-hour running test according to methods similar to those described above. Results are shown in table 2.
(42) TABLE-US-00002 TABLE 2 Working Working Working Working Working Working Working Working Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Unbonded region Yes Yes Yes Yes Yes Yes Yes Yes present? Disposition of FIG. 2 FIG. 2 FIG. 2 FIG. 2 FIG. 2 FIG. 2 FIG. 8 FIG. 8 unbonded region along circumferential direction Plan-view shape of FIG. 3 FIG. 3 FIG. 3 FIG. 3 FIG. 3 FIG. 3 FIG. 5 FIG. 5 unbonded region Sound-absorbing 60 170 80 80 80 80 80 80 member hardness (N) Sound-absorbing 60 180 90 90 90 90 90 90 member tensile strength (kPa) Adhesive layer 16 16 8 40 16 16 16 16 peeling adhesive strength (N/20 mm) Angle θ at which cut- 180 180 180 180 135, 225 120, 240 90, 120, 70, 120, out section(s) and 150 170 unbonded region(s) are disposed Peeling of sound- No No No No No No No No absorbing member present? Peeling resistance 120 120 110 140 130 120 150 140
(43) As shown in table 2, the tires of Working Examples 4 to 7, which had different sound-absorbing member hardnesses, sound-absorbing member tensile strengths, and adhesive layer peeling adhesive strengths, exhibited no peeling of the sound-absorbing member whatsoever after 100 hours of running, as in the case of Working Examples 1 and 3. In addition, as is clear from a comparison of Working Example 8 and Working Example 9 and a comparison of Working Example 10 and Working Example 11, defining n as the total number of cut-out sections and unbonded regions, a reference angle α as 360°/n, and a tolerance angle β as 90°/n, satisfactory effects were yielded when the angle θ at which the cut-out sections and unbonded regions were actually disposed satisfied the relationship α−β≤θ≤α+β.