JP2013112062A - Pneumatic tire with noise damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve rolling resistance of a tire, while suppressing increase in the manufacturing cost thereof.SOLUTION: A pneumatic tire T with a noise damper includes: a pneumatic tire 1 in which a tread rubber 9 coming in contact with ground on a road surface is arranged in a tread section 2; and a noise damper 10 which is fixed to a tire cavity surface N of the pneumatic tire 1, and which is composed of a sponge material of a specific gravity of 0.016 to 0.035. A loss tangent tanδof the tread rubber 9 is 0.13 to 0.18. The noise damper 10 has such a horizontally long shape that a length W along the tire cavity surface N is longer than a thickness t perpendicular to the tire cavity surface N. Moreover, the noise damper 10 is arranged closed to a shoulder side of the tread section 2 so as to intersect a tire radial directional line Cn passing through the ground-contact end Te of the tread section 2.

Description

  The present invention relates to a pneumatic tire with a sound control body that improves the rolling resistance performance of a tire while suppressing an increase in manufacturing cost.

  Conventionally, in order to improve the rolling resistance performance of a tire, it is known to use a rubber having a small loss tangent tan δ for the tread rubber disposed in the tread portion and to reduce deformation of the tread rubber itself.

  However, in order to reduce the loss tangent tan δ of the tread rubber, a special rubber material, polymer, or the like has to be used, and there is a problem that the manufacturing cost increases. Moreover, in order to reduce the deformation of the tread rubber itself, it is effective to provide grooves, siping, etc. in the tread part, but the tire provided with such grooves and siping has a greater heat dissipation effect, Tread rubber temperature tends to decrease excessively. In general, the loss tangent tan δ of rubber has a temperature dependency and becomes smaller as the temperature becomes higher. Therefore, such a low-temperature tread rubber has a problem that the loss tangent tan δ is increased and the rolling resistance is deteriorated. It was. As related technologies, there are Patent Documents 1 and 2 below.

Japanese Patent Laid-Open No. 2005-212524 JP 2005-138760 A

  The present invention has been devised in view of the above circumstances, and is basically based on specifying the shape and location of a noise control member that is fixed to the tire lumen surface of a pneumatic tire and extends in the tire circumferential direction. The main object of the present invention is to provide a pneumatic tire with a sound control body that improves the rolling resistance performance of the tire while suppressing an increase in manufacturing cost.

  The invention according to claim 1 of the present invention is a pneumatic tire in which a tread rubber that is in contact with the road surface is disposed in the tread portion, and a specific gravity that is fixed to the inner surface of the pneumatic tire and extends in the tire circumferential direction is zero. A pneumatic tire with a sound control body comprising a sound control body made of a sponge material of .016 to 0.035, wherein the tread rubber has a loss tangent tan δ of 0.13 to 0.18. In the meridional section including the rotation axis, the sound damping body has a horizontally long shape in which the length along the tire cavity surface is larger than the thickness perpendicular to the tire lumen surface, and the sound damping body includes the tread portion. The tire is arranged close to the shoulder side of the tread portion so as to cross a tire radial direction line passing through the ground contact end.

  In the invention according to claim 2, the inner end in the tire axial direction of the sound absorber is located at a position of 17.5 to 22.5% of the tread ground contact width inward in the tire axial direction from the ground contact end. The pneumatic tire with a sound absorber according to claim 1, wherein an outer end of the sound body in the tire axial direction is located at a position 70 to 77% of a tire cross-sectional height from a bead base line.

  The invention according to claim 3 is the pneumatic tire with a noise damper according to claim 1 or 2, wherein the thickness of the noise damper is 5 to 10 mm.

  The pneumatic tire with a sound control body of the present invention has a pneumatic tire in which a tread rubber that is in contact with the road surface is disposed on the tread portion, and a specific gravity that is fixed to a lumen surface of the pneumatic tire and extends in a tire circumferential direction. A sound control body made of sponge material of .016 to 0.035. Such a sponge material suppresses the lowering of the temperature of the rubber by preventing the heat radiation of the tread rubber in the portion where the sponge material is fixed. Accordingly, the loss tangent tan δ of the tread rubber is reduced, and the rolling resistance performance is improved.

  As the tread rubber, rubber having a loss tangent tan δ of 0.13 to 0.18 is used. Thus, since loss tangent tan-delta is specified as 0.18 or less, the hysteresis loss at the time of driving | running | working can be made small, and rolling resistance improves. Further, since the loss tangent tan δ is specified to be 0.13 or more, a special rubber material or the like is not used, and an increase in manufacturing cost is suppressed.

  Further, in the meridian cross section including the tire rotation axis, the sound damping body has a horizontally long shape in which the length along the tire lumen surface is larger than the thickness perpendicular to the tire lumen surface. And the breakage due to tire vibration and roll is suppressed. Thereby, the improvement effect of the above-mentioned rolling resistance is exhibited reliably. Further, the sound damping body is arranged close to the shoulder side of the tread portion so as to cross a tire radial direction line passing through the ground contact end of the tread portion. That is, since the sound damping body of the present invention is disposed on the shoulder side including the inside of the grounding end having a small grounding area and a large heat dissipation effect, the temperature of the tread rubber is ensured to be high and the rolling resistance is further improved. Can do. Therefore, the pneumatic tire with a noise control body of the present invention effectively improves the rolling resistance of the tire while suppressing the manufacturing cost.

It is sectional drawing which shows one Embodiment of the pneumatic tire with a noise suppression body of this invention. FIG. 2 is a circumferential cross-sectional view of the pneumatic tire with a noise control body of FIG. 1. (A) thru | or (d) are right-half sectional drawing of the pneumatic tire with a noise suppression body of the comparative examples 2-5.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a pneumatic tire T with a sound control body according to the present embodiment, and FIG. 2 is a cross-sectional view in the circumferential direction of a portion where the sound control body is arranged. The cross-sectional view of FIG. 1 represents a meridian cross section including a tire rotation axis in a normal state in which the rim is assembled on a normal rim (not shown) and is filled with a normal internal pressure. When there is no notice in particular, the dimension of each part of a tire, etc. are values measured in this normal state.

  The “regular rim” is a rim defined for each tire in the standard system including the standard on which the tire is based. “Standard Rim” for JATMA, “Design Rim” for TRA For ETRTO, "Measuring Rim". In addition, the “regular internal pressure” is an air pressure determined by each standard for each tire in the standard system including the standard on which the tire is based. The maximum value described in TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES is "INFLATION PRESSURE" for ETRTO, but 180 kPa for tires for passenger cars.

  The pneumatic tire T with a noise control body is fixed to a toroidal pneumatic tire (hereinafter sometimes simply referred to as “tire”) 1 and a lumen surface N of the tire 1 and in the tire circumferential direction. And the extending sound control body 10.

  The tire 1 is a tubeless tire, and is disposed on the tread portion 2, a pair of sidewall portions 3 extending inward in the tire radial direction from both ends in the tire axial direction, and on the inner side in the tire radial direction of each sidewall portion 3. The tire bore surface N is covered with an inner liner rubber 8 made of an air-impermeable rubber. As such a tire 1, various tires can be applied without being restricted by its internal structure or category.

  Further, the tire 1 of the present embodiment is arranged in a carcass 6 that extends from the tread portion 2 through the sidewall portion 3 to the bead core 5 of the bead portion 4, radially outside the carcass 6 and inside the tread portion 2. Belt layer 7. The tread portion 2 is appropriately provided with a draining groove G.

  The carcass 6 includes a main body part 6a straddling a pair of bead cores 5 and 5 in a toroidal manner, and a folded part 6b which is continuous from both sides of the main body part 6a and is folded around the bead core 5 from the inner side to the outer side in the tire axial direction. And at least one carcass ply 6A in this embodiment.

  The belt layer 7 is composed of at least two belt plies 7A and 7B, in the present embodiment, in the tire radial direction, and in the outer two. Each belt ply 7A, 7B has a highly elastic belt cord such as a steel cord inclined at an angle of 15 to 40 ° with respect to the tire equator C. The belt plies 7A and 7B are overlapped so that the belt cords intersect each other.

  In the tread portion 2 of the present embodiment, a tread rubber 9 that contacts the road surface is disposed outside the belt layer 7 in the tire radial direction.

  The tread rubber 9 needs to be a rubber having a loss tangent tan δ of 0.13 to 0.18. That is, if the loss tangent tan δ exceeds 0.18, the hysteresis loss during traveling cannot be reduced, and the rolling resistance performance deteriorates. Further, if the loss tangent tan δ is less than 0.13, it is necessary to use a special rubber material or the like in order to ensure wet performance, and the manufacturing cost increases. Note that the loss tangent tan δ is preferably 0.14 or more and preferably 0.17 or less in order to further improve the rolling resistance performance and the manufacturing cost in a well-balanced manner. Further, in this specification, the loss tangent of rubber is a value measured using a viscoelastic spectrometer under conditions of a temperature of 70 ° C., a frequency of 10 Hz, an initial tensile strain of 10%, and a dynamic strain amplitude of ± 2%.

  Further, the tread rubber 9 of the present embodiment extends continuously from the outside of the ground contact end Te to the inside in the tire axial direction. Thereby, the above-mentioned operation is more effectively exhibited. When the tread rubber 9 is made of a plurality of rubber layers such as cap rubber and base rubber, at least the rubber of the outermost rubber layer in contact with the road surface only needs to satisfy the loss tangent tan δ.

  The “grounding end” Te is defined as a grounding position on the outermost side in the tire axial direction when a normal load is applied to the tire in the normal state and grounded on a plane with a camber angle of 0 degree. The distance in the tire axial direction between the ground contact Te and Te is determined as the tread ground contact width TW. The “regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. “Maximum load capacity” for JATMA, “Table for TRA” The maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” is “LOAD CAPACITY” in the case of ETRTO.

  The sound damper 10 is made of a sponge material having a sponge-like porous structure. In this embodiment, for example, an open-cell sponge material made of polyurethane is used. Such a sound damping body 10 prevents the heat of the rubber (the tread rubber 9 in this embodiment) to which the sponge material is fixed, thereby suppressing the low temperature of the rubber. Therefore, the sound damper 10 reduces the loss tangent tan δ of the tread rubber 9 and improves the rolling resistance performance.

  Further, the sound control body 10 of the present embodiment needs to be configured with a specific gravity of 0.016 to 0.035. That is, when the specific gravity is smaller than 0.016, the above-described rubber heat dissipation suppression effect cannot be exhibited, and the durability of the sound damper 10 is deteriorated. Conversely, when the specific gravity exceeds 0.035, the manufacturing cost increases and the tire mass increases. In addition, the specific gravity of the sponge material is a value obtained by converting the apparent density measured in accordance with the “apparent density” of the fifth term defined in “Soft urethane foam test method” of JISK6400 into specific gravity. And

  Further, the sound damper 10 has a horizontally long shape in which the length W along the tire lumen surface N is greater than the thickness t perpendicular to the tire lumen surface N in the tire meridian cross section. Such a sound control body 10 has improved rigidity, and is prevented from being broken by vibration or rolling of the tire. Thereby, the improvement effect of the above-mentioned rolling resistance performance is exhibited over a long period of time. In addition, in order to exhibit the said effect | action effectively, 0.05-0.5 is desirable for ratio t / W of the said length W and thickness t.

  In addition, if the thickness t is small, the rolling resistance performance may not be improved. Conversely, if the thickness t is large, the manufacturing cost may be excessively increased rather than the rolling resistance performance. . For this reason, the thickness t is preferably 5 to 10 mm.

  Further, the sound damping body 10 needs to be arranged close to the shoulder side of the tread portion 2 so as to cross the tire radial direction line Cn passing through the ground contact end Te of the tread portion 2. That is, since the sound damping body 10 of the present invention is arranged on the shoulder side including the inner side of the grounding end Te having a small grounding region and a large heat dissipation effect, the temperature of the tread rubber 9 is ensured to be higher and the rolling resistance performance. Can be further improved. As shown in FIG. 1, the sound damping body 10 of the present embodiment is composed of a pair disposed on the inner cavity surface N of the left and right contact ends Te in the tire radial direction, and the temperature of the tread rubber 9 is It is secured even higher.

  Further, it is desirable that the inner end 10i in the tire axial direction of the sound damping body 10 is located at a position of 17.5 to 22.5% of the tread ground contact width TW inward in the tire axial direction from the ground contact Te. That is, if the inner end 10i is excessively far from the ground contact end Te toward the inner side in the tire axial direction, the manufacturing cost may be increased more than the heat dissipation suppression effect of the tread rubber 9. On the contrary, if the inner end 10i is arranged on the outer side in the tire axial direction, the heat dissipation suppressing effect may not be exhibited. For this reason, the inner end 10i is more preferably located at a position of 19% or more of the tread ground contact width TW, and preferably at a position of 21% or less. The distance in the tire axial direction from the ground contact Te to the inner end 10i is indicated by L1.

  Further, from the same viewpoint, the outer end 10e of the noise damper 10 in the tire axial direction is preferably located at a position 70% or more, more preferably 72% or more of the tire cross-section height TH from the bead base line BL. Desirably, it is desirable to be in the position of 77% or less, more preferably 75% or less. The distance in the tire radial direction from the bead base line BL to the outer end 10e is indicated by L2.

  In addition, it is desirable that the sound control body 10 of the present embodiment extends in the tire circumferential direction with substantially the same cross-sectional shape in order to ensure rolling resistance performance. Note that “substantially” includes the same cross-sectional shape over the entire tire circumferential direction, as shown in FIG. 2, the cross-sectional shapes of both ends 10 u and 10 u in the circumferential direction of the noise suppressor are as follows: Including the case of a taper shape.

  As mentioned above, although the pneumatic tire of this invention was demonstrated in detail, it cannot be overemphasized that this invention can be changed into various aspects, without being limited to said specific embodiment.

A pneumatic tire with a size of 175 / 65R15 that forms the basic configuration of the tread portion shown in FIG. 1 was prototyped based on the specifications in Table 1, and the noise performance and drainage performance of each sample tire were tested. . The tire of Comparative Example 1 is not provided with a noise control body. The common specifications are as follows.
Tread contact width TW: 148mm
Tire cross section height TH: 115mm
Sponge specific gravity: 0.025
The test method is as follows.

<Rolling resistance performance>
Using a rolling resistance tester, rolling resistance was measured under the following conditions. The results were expressed as an index with Comparative Example 1 as 100. The smaller the value, the smaller the rolling resistance and the better.
Room temperature: 25 ° C
Internal pressure: 210 kPa
Load: 3.92kN
Speed: 80km / h

<Surface temperature of shoulder>
In the rolling resistance test, the temperature of the tire surface immediately before the end of the test was measured with a non-contact type surface thermometer. There are two measurement points: a 15 mm contact surface on the inner side in the tire axial direction from the contact end, and a 10 mm buttress surface on the outer side in the tire axial direction from the contact end. As a result, the average value of the two locations is expressed, and the larger the numerical value, the better the rolling resistance performance.

<Manufacturing cost>
The manufacturing cost required to manufacture one tire is indicated by an index with Comparative Example 1 as 100. The smaller the numerical value, the smaller the manufacturing cost and the better.

  As a result of the test, it can be confirmed that the rolling resistance performance and the manufacturing cost of the tire of the example are improved in a well-balanced manner as compared with the tire of the comparative example. In addition, the experiment was performed by changing the specific gravity of the sponge from 0.016 to 0.035, and the same result was obtained.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 9 Tread rubber 10 Damping body N Tire inner surface Te Grounding end

Claims (3)

A pneumatic tire in which a tread rubber that is in contact with the road surface is disposed on the tread portion, and a sponge material having a specific gravity of 0.016 to 0.035 fixed to the inner surface of the pneumatic tire and extending in the tire circumferential direction. A pneumatic tire with a sound control body including a sound body,
The tread rubber has a loss tangent tan δ of 0.13 to 0.18,
In the meridian cross section including the tire rotation axis,
The sound damping body has a horizontally long shape in which the length along the tire lumen surface is larger than the thickness perpendicular to the tire lumen surface,
In addition, the pneumatic tire with a noise damper is characterized in that the noise damper is arranged close to the shoulder side of the tread portion so as to cross a tire radial direction line passing through the ground contact end of the tread portion. The inner end in the tire axial direction of the sound control body is located at a position of 17.5 to 22.5% of the tread ground contact width inward in the tire axial direction from the ground contact end,
2. The pneumatic tire with a sound damper according to claim 1, wherein an outer end of the sound damper in the tire axial direction is at a position 70 to 77% of a tire cross-section height from a bead base line.   The pneumatic tire with a sound absorber according to claim 1 or 2, wherein the sound absorber has a thickness of 5 to 10 mm.

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