JP6281265B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire in which a band-shaped sound absorbing material is bonded to a region corresponding to a tread portion on the inner surface of the tire, and more specifically, even when the sound absorbing material is disposed in the entire region in the tire circumferential direction. The present invention relates to a pneumatic tire that can prevent abrasion of an end surface and suppress peeling of a sound absorbing material.

  In a pneumatic tire, one of the causes for generating noise is cavity resonance sound caused by vibration of air filled in the tire. The cavity resonance sound is generated when the tread portion vibrates due to road surface irregularities when the tire rolls, and the vibration of the tread portion vibrates the air inside the tire.

  As a technique for reducing noise due to such a cavity resonance phenomenon, it has been proposed to arrange a sound absorbing material in a cavity formed between a tire and a rim of a wheel. More specifically, a band-shaped sound absorbing material is bonded to a region corresponding to the tread portion on the inner surface of the tire (see, for example, Patent Documents 1 and 2).

  However, when trying to arrange the band-shaped sound absorbing material without any gap over the entire region in the tire circumferential direction, the end surfaces thereof are in contact with each other, so there is a problem that the end surfaces of the sound absorbing material rub against each other during tire travel and cause wear. is there. Further, when the end surfaces of the sound absorbing material are rubbed with each other during running of the tire, there is a problem in that the sound absorbing material bonded to the tire inner surface is peeled off at the end in the tire circumferential direction, and the sound absorbing material is peeled off as a starting point.

  In addition, it is also possible to arrange | position a sound absorption material intermittently along a tire peripheral direction so that the end surfaces of a strip | belt-shaped sound absorption material may not mutually contact. However, when the band-shaped sound absorbing material is intermittently arranged along the tire circumferential direction, in addition to the deterioration of mass balance, the volume of the sound absorbing material cannot be sufficiently secured and the sound absorbing effect is reduced. There is. Therefore, it is desired to dispose the band-shaped sound absorbing material over the entire region in the tire circumferential direction and prevent the sound absorbing material from being worn or peeled off.

JP 2002-67608 A JP 2005-138760 A

  An object of the present invention is to provide a pneumatic tire capable of preventing wear of the end face of the sound absorbing material and suppressing peeling of the sound absorbing material even when the sound absorbing material is disposed in the entire region in the tire circumferential direction. It is to provide.

In order to solve the above-described object, the pneumatic tire of the present invention includes an annular tread portion extending in the tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and the sidewall portions. A pair of bead portions disposed on the inner side in the tire radial direction of the tire, and a pneumatic tire in which a band-shaped sound absorbing material is bonded to a region corresponding to the tread portion on the tire inner surface via an adhesive layer along the tire circumferential direction. the sound absorbing material is composed of a plurality of divided pieces which are divided at a plurality of locations in the tire circumferential direction, with substantially arranged to form a single column the sound-absorbing material over the entire circumferential direction of the tire, the tire The pair of end surfaces are arranged at positions shifted in the tire width direction so that the pair of end surfaces of the sound absorbing material arranged at the same circumferential direction do not contact each other.

  In the present invention, in a pneumatic tire in which a band-shaped sound absorbing material is bonded to a region corresponding to the tread portion of the tire inner surface via an adhesive layer along the tire circumferential direction, the sound absorbing material is substantially simply spread over the entire region in the tire circumferential direction. The pair of end surfaces are disposed at positions shifted in the tire width direction so that the pair of end surfaces of the sound absorbing material disposed at the same position in the tire circumferential direction do not contact each other. Thus, even when the sound absorbing material is disposed in the entire region in the tire circumferential direction, contact between the end surfaces of the sound absorbing material can be avoided, and wear of the end surfaces of the sound absorbing material can be prevented. Moreover, since the end surfaces of the sound absorbing material do not contact each other, peeling of the sound absorbing material can be suppressed. As a result, the noise reduction effect based on the sound absorbing material can be maintained over a long period of time.

  In addition, since the band-shaped sound absorbing material is disposed over the entire region in the tire circumferential direction, the mass balance in the tire circumferential direction can be kept good. Further, by arranging the belt-like sound absorbing material over the entire region in the tire circumferential direction, the volume of the sound absorbing material can be sufficiently ensured, and a good sound absorbing effect can be exhibited based on the sound absorbing material.

  In the present invention, the sound absorbing material is preferably arranged so as to extend linearly at a certain angle with respect to the tire circumferential direction. In this way, by inclining the sound absorbing material with respect to the tire circumferential direction, the pair of end surfaces of the sound absorbing material arranged at the same position in the tire circumferential direction can be arranged at positions shifted in the tire width direction. Moreover, since the sound absorbing material is extended linearly, it is possible to avoid occurrence of shear stress on the sound absorbing material bonding surface, unlike the case where the sound absorbing material is bonded in a bent state, and good adhesion is achieved. Durability can be ensured.

  Alternatively, it is also possible to arrange the sound absorbing material so as to meander along the tire circumferential direction. Also in this case, the pair of end surfaces of the sound absorbing material disposed at the same position in the tire circumferential direction can be disposed at positions shifted in the tire width direction.

Sound absorbing material, that is composed of a plurality of divided pieces which are divided at a plurality of locations in the tire circumferential direction. In particular, when the sound absorbing material is composed of a plurality of divided pieces divided at a plurality of locations in the tire circumferential direction, there is an advantage that shear stress generated on the bonding surface of the sound absorbing material is alleviated.

  The ratio of the volume of the sound absorbing material to the volume of the cavity formed in the tire when the rim is assembled is preferably larger than 20%. Thus, by increasing the volume of the sound absorbing material, an excellent noise reduction effect can be obtained, and even in the case of a large sound absorbing material, a good adhesion state can be ensured over a long period of time. The volume of the cavity is the volume of the cavity formed between the tire and the rim in a state where the tire is assembled on the regular rim and filled with the regular internal pressure. The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based, for example, a standard rim for JATMA, “Design Rim” for TRA, or ETRTO. Then, “Measuring Rim” is set. However, when the tire is a tire mounted on a new vehicle, the volume of the cavity is determined using a genuine wheel in which the tire is assembled. “Regular internal pressure” is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. The maximum air pressure is JATMA, and the table “TIRE ROAD LIMITS AT VARIOUS” is TRA. The maximum value described in “COLD INFRATION PRESURES”, “INFLATION PRESURE” if it is ETRTO, but if the tire is a new car mounted tire, the air pressure displayed on the vehicle is used.

  The sound absorbing material has a hardness of 60N to 170N, and the sound absorbing material preferably has a tensile strength of 60 kPa to 180 kPa or more. The sound absorbing material having such physical properties is excellent in durability against shear strain. The hardness of the sound absorbing material is measured in accordance with JIS-K6400-2 “Soft foam material—physical characteristics—Part 2: Determination of hardness and compressive stress—strain characteristics”. It is measured by the method (a method for obtaining a force after 20 seconds after a constant compression of 25%). The tensile strength of the sound absorbing material is measured in accordance with JIS-K6400-5 “Soft foam material—physical properties—Part 5: Determination of tensile strength, elongation and tear strength”.

  The adhesive layer is composed of a double-sided adhesive tape, and the peel adhesive strength thereof is preferably in the range of 8 N / 20 mm to 40 N / 20 mm. As a result, it is possible to easily perform the attaching operation of the sound absorbing material and the dismantling operation at the time of discarding the tire while keeping the fixing strength of the sound absorbing material good. The peel adhesive strength of the double-sided adhesive tape is measured according to JIS-Z0237. That is, the double-sided PSA sheet is lined with a 25 μm thick PET film. The backed adhesive sheet is cut into a 20 mm × 200 mm square to produce a test piece. The release liner is peeled from the test piece, and the exposed adhesive surface is attached to a stainless steel (SUS304, surface finish BA) plate as an adherend by reciprocating a 2 kg roller. After maintaining this in an environment of 23 ° C. and 50% RH for 30 minutes, using a tensile tester, in accordance with JIS Z 0237, in an environment of 23 ° C. and RH 50%, a peeling angle of 180 ° and a tensile speed of 300 mm / min. Under the conditions described above, the 180 ° peeling adhesion to the SUS plate is measured.

1 is a perspective sectional view showing a pneumatic tire according to an embodiment of the present invention. 1 is an equatorial line cross-sectional view showing a pneumatic tire according to an embodiment of the present invention. It is an expanded view which shows an example (reference example) of the sound-absorbing material adhere | attached on the inner surface of the pneumatic tire of this invention. It is an expanded view which shows the modification of the sound-absorbing material adhere | attached on the inner surface of the pneumatic tire of this invention. It is an expanded view which shows the other modification (reference example) of the sound-absorbing material adhere | attached on the inner surface of the pneumatic tire of this invention. It is an expanded view which shows the other modification (reference example) of the sound-absorbing material adhere | attached on the inner surface of the pneumatic tire of this invention.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 show a pneumatic tire according to an embodiment of the present invention. 1 and 2, the pneumatic tire of the present embodiment includes a tread portion 1 that extends in the tire circumferential direction and has an annular shape, and a pair of sidewall portions 2 that are disposed on both sides of the tread portion 1. A pair of bead portions 3 are provided inside the sidewall portions 2 in the tire radial direction.

  In the pneumatic tire, a band-shaped sound absorbing material 6 is bonded to a region corresponding to the tread portion 1 of the tire inner surface 4 via an adhesive layer 5 along the tire circumferential direction. The sound absorbing material 6 is made of a porous material having open cells, and has predetermined sound absorbing characteristics based on the porous structure. As the porous material of the sound absorbing material 6, foamed polyurethane may be used. On the other hand, as the adhesive layer 5, a paste adhesive or a double-sided adhesive tape can be used.

  FIG. 3 shows an example of the sound absorbing material 6 bonded to the inner surface of the pneumatic tire of the present invention, and shows a region corresponding to the tread portion 1 of the tire inner surface 4 over the entire region in the tire circumferential direction. In FIG. 3, Tc is the tire circumferential direction, and Tw is the tire width direction. As shown in FIG. 3, the sound absorbing material 6 is disposed so as to form a substantially single row over the entire region in the tire circumferential direction Tc, and a pair of the sound absorbing materials 6 disposed at the same position in the tire circumferential direction Tc. The pair of end surfaces 6a and 6b are arranged at positions shifted in the tire width direction Tw so that the end surfaces 6a and 6b do not contact each other.

  More specifically, the single sound absorbing material 6 is arranged so as to extend linearly at a certain angle with respect to the tire circumferential direction Tc. When the sound absorbing material 6 processed into a straight line is bonded to the tire inner surface 4 in a state of extending linearly, the sound absorbing material 6 is sheared to the bonding surface of the sound absorbing material 6 unlike when the sound absorbing material 6 is bonded in a bent state. There is no stress. Therefore, good adhesion durability can be secured for the sound absorbing material 6.

  Here, arranging the sound absorbing material 6 so as to form a substantially single row over the entire region in the tire circumferential direction Tc means that the total length in the longitudinal direction of the sound absorbing material 6 is substantially equal to the tire inner circumferential length. More specifically, the total length in the longitudinal direction of the sound absorbing material 6 is 97% to 110%, preferably 99% to 108%, more preferably 100% to 105% of the tire inner circumferential length. % Range.

  In the pneumatic tire described above, when the belt-like sound absorbing material 6 is bonded to the region corresponding to the tread portion 1 of the tire inner surface 4 along the tire circumferential direction Tc via the adhesive layer 5, the sound absorbing material 6 is attached to the tire circumferential direction Tc. The pair of end surfaces are arranged so as to form a substantially single row over the entire region of the tire, and the pair of end surfaces 6a, 6b of the sound absorbing material 6 disposed at the same position in the tire circumferential direction Tc are not in contact with each other. By arranging 6a and 6b at positions shifted in the tire width direction Tw, contact between the end surfaces 6a and 6b of the sound absorbing material 6 is avoided even when the sound absorbing material 6 is arranged in the entire region in the tire circumferential direction Tc. In addition, wear of the end surfaces 6a and 6b of the sound absorbing material 6 can be prevented. Moreover, since the end surfaces 6a and 6b of the sound absorbing material 6 do not contact each other, peeling occurs at the end portion of the sound absorbing material 6 in the tire circumferential direction Tc, thereby avoiding the inconvenience that the sound absorbing material 6 is peeled off as a starting point. Can do. As a result, peeling of the sound absorbing material 6 can be suppressed, and the noise reduction effect based on the sound absorbing material 6 can be maintained over a long period of time.

  And since the strip | belt-shaped sound-absorbing material 6 is arrange | positioned over the whole region of the tire circumferential direction Tc, the mass balance of the tire circumferential direction Tc can be kept favorable. In addition, by arranging the belt-like sound absorbing material 6 over the entire region in the tire circumferential direction Tc, a sufficient volume of the sound absorbing material 6 can be secured, and a good sound absorbing effect can be exhibited based on the sound absorbing material 6. .

  FIG. 4 shows a modification of the sound absorbing material 6 bonded to the inner surface of the pneumatic tire of the present invention, and shows a region corresponding to the tread portion 1 of the tire inner surface 4 over the entire region in the tire circumferential direction. In FIG. 4, the sound absorbing material 6 is composed of a plurality of divided pieces 61, 62, 63, 64 divided at a plurality of locations in the tire circumferential direction Tc. Each of the divided pieces 61 to 64 of the sound absorbing material 6 has an end face 6a on one side in the tire circumferential direction and an end face 6b on the other side in the tire circumferential direction. The divided pieces 61 to 64 of the sound absorbing material 6 are arranged so as to form a substantially single row over the entire region in the tire circumferential direction Tc, and a pair of the sound absorbing materials 6 arranged at the same position in the tire circumferential direction Tc. The pair of end surfaces 6a and 6b are arranged at positions shifted in the tire width direction Tw so that the end surfaces 6a and 6b do not contact each other.

  In this case as well, when the sound absorbing material 6 is disposed in the entire region in the tire circumferential direction Tc, wear of the end surfaces 6a and 6b of the sound absorbing material 6 can be prevented and peeling of the sound absorbing material 6 can be suppressed. Further, when the length of the sound absorbing material 6 in the tire circumferential direction increases, shear stress generated on the bonding surface tends to increase. However, the sound absorbing material 6 is divided into a plurality of divided pieces 61 to 61 divided at a plurality of locations in the tire circumferential direction Tc. When comprised from 64, the shear stress which arises in the adhesion surface can be relieved.

  FIG. 5 shows another modification of the sound absorbing material 6 bonded to the inner surface of the pneumatic tire of the present invention, and shows a region corresponding to the tread portion 1 of the tire inner surface 4 over the entire region in the tire circumferential direction. is there. In FIG. 5, the single sound absorbing material 6 extends along the tire circumferential direction Tc, and the sound absorbing material 6 is disposed so as to meander in the vicinity of the end faces 6 a and 6 b. Also in this case, the pair of end surfaces 6a and 6b of the sound absorbing material 6 arranged at the same position in the tire circumferential direction Tc can be arranged at positions shifted in the tire width direction Tw.

  FIG. 6 shows another modification of the sound absorbing material 6 bonded to the inner surface of the pneumatic tire of the present invention, and shows a region corresponding to the tread portion 1 of the tire inner surface 4 over the entire region in the tire circumferential direction. is there. In FIG. 6, the single sound absorbing material 6 is disposed so as to meander along the tire circumferential direction Tc. More specifically, the sound absorbing material 6 meanders in a wavy pattern periodically along the tire circumferential direction Tc. Also in this case, the pair of end surfaces 6a and 6b of the sound absorbing material 6 arranged at the same position in the tire circumferential direction Tc can be arranged at positions shifted in the tire width direction Tw.

  In the pneumatic tire, a single sound absorbing material 6 extends in the tire circumferential direction, and the sound absorbing material 6 has a uniform thickness in a range corresponding to at least an adhesive surface in a cross section perpendicular to the longitudinal direction. The cross-sectional shape is preferably constant along the longitudinal direction. In particular, the cross-sectional shape of the cross section orthogonal to the longitudinal direction of the sound absorbing material 6 is preferably a rectangle (including a square), but depending on the case, it may be an inverted trapezoid so that the bonding surface side becomes narrow. . Thereby, the capacity | capacitance of the sound-absorbing material 6 per adhesion area can be maximized, and an excellent noise reduction effect can be obtained. Further, since the sound absorbing material 6 having such a shape is easy to process, the manufacturing cost is also low.

  When the rim of the pneumatic tire is assembled, a cavity 7 is formed between the tire inner surface 4 and the rim, and the volume ratio of the sound absorbing material 6 to the volume of the cavity 7 is larger than 20%. preferable. Thus, by increasing the volume of the sound absorbing material 6, an excellent noise reduction effect can be obtained, and even in the case of the large sound absorbing material 6, a good adhesion state can be secured for a long period of time. The width of the sound absorbing material 6 is preferably in the range of 30% to 90% of the tire ground contact width.

  The sound absorbing material 6 has a hardness (JIS-K6400-2) of 60N to 170N, and the sound absorbing material 6 preferably has a tensile strength (JIS-K6400-5) of 60 kPa to 180 kPa. The sound absorbing material 6 having such physical properties has excellent durability against shear strain. If the hardness or tensile strength of the sound absorbing material 6 is too small, the durability of the sound absorbing material 6 will be reduced. In particular, the hardness of the sound absorbing material 6 is preferably 70N to 160N, and more preferably 80N to 140N. The tensile strength of the sound absorbing material 6 is preferably 75 kPa to 165 kPa, more preferably 90 kPa to 150 kPa.

  The adhesive layer 5 preferably has a peel adhesive strength (JIS-Z0237: 2009) in the range of 8 N / 20 mm to 40 N / 20 mm. Thereby, it is possible to easily perform the attaching operation of the sound absorbing material 6 and the dismantling operation at the time of discarding the tire while keeping the fixing strength of the sound absorbing material 6 good. That is, if the peeling force of the adhesive layer 5 is too weak, the fixed state of the sound absorbing material 6 becomes unstable. Conversely, if the peeling force of the adhesive layer 5 is too strong, the attaching position is changed in the attaching operation of the sound absorbing material 6. It becomes difficult to peel off the sound absorbing material 6 when the tire is discarded. In particular, the peel adhesive strength of the adhesive layer 5 is preferably 9 N / 20 mm to 30 N / 20 mm, more preferably 10 N / 20 mm to 25 N / 20 mm.

The tire size is 275 / 35R20 and extends in the tire circumferential direction to form an annular tread portion, a pair of sidewall portions disposed on both sides of the tread portion, and the sidewall portions disposed on the inner side in the tire radial direction. And a pair of bead portions, and in a pneumatic tire in which a band-shaped sound absorbing material is bonded to a region corresponding to the tread portion on the inner surface of the tire via an adhesive layer along the tire circumferential direction, the arrangement of the sound absorbing material is varied. The tires of Comparative Example 1 , Example 1, and Reference Examples 1 to 3 were manufactured.

  In Comparative Example 1, the sound absorbing material is composed of a single sound absorbing material, and the sound absorbing material is disposed so as to form a substantially single row over the entire region in the tire circumferential direction, and is disposed at the same position in the tire circumferential direction. The pair of end surfaces are arranged at the same position in the tire width direction so that the pair of end surfaces of the sound absorbing material to be in contact with each other.

In Reference Example 1 , as shown in FIG. 3, the sound absorbing material is composed of a single sound absorbing material, and the sound absorbing material is arranged so as to extend linearly at a certain angle with respect to the tire circumferential direction. The pair of end surfaces of the sound absorbing material disposed at the same position in the tire circumferential direction are arranged at positions shifted in the tire width direction so as not to contact each other.

In Example 1 , as shown in FIG. 4, the sound absorbing material is composed of a plurality of divided pieces divided at a plurality of locations in the tire circumferential direction, and the sound absorbing material is linearly formed at a certain angle with respect to the tire circumferential direction. The pair of end surfaces are arranged at positions shifted in the tire width direction so that the pair of end surfaces of the sound absorbing material arranged at the same position in the tire circumferential direction do not contact each other.

In Reference Example 2 , as shown in FIG. 5, the sound absorbing material is composed of a single sound absorbing material, and the sound absorbing material is disposed so as to meander in the vicinity of its end surface, and is disposed at the same position in the tire circumferential direction. The pair of end surfaces are arranged at positions shifted in the tire width direction so that the pair of end surfaces of the sound absorbing material do not contact each other.

In Reference Example 3 , as shown in FIG. 6, the sound absorbing material is composed of a single sound absorbing material, and the sound absorbing material is arranged so as to meander periodically along the tire circumferential direction, and the same position in the tire circumferential direction. The pair of end surfaces of the sound-absorbing material disposed at the positions are arranged at positions shifted in the tire width direction so that they do not contact each other.

In Comparative Example 1 , Example 1 and Reference Examples 1 to 3 , the following matters were made common. The cross-sectional shape in the cross section orthogonal to the longitudinal direction of the sound absorbing material was a rectangle, and the cross-sectional shape was constant along the tire circumferential direction. The ratio of the volume of the sound absorbing material to the volume of the cavity formed in the tire when assembling the rim was 25%. The sound absorbing material had a hardness of 91 N and the sound absorbing material had a tensile strength of 132 kPa. The adhesive strength for peeling off the adhesive layer was 16 N / 20 mm.

The pneumatic tires of Comparative Example 1 , Example 1 and Reference Examples 1 to 3 are assembled on a wheel having a rim size of 20 × 9.5 J, respectively. The 100-hour running test was carried out, and then the presence or absence of end-face wear of the sound absorbing material and the presence or absence of adhesion peeling of the sound absorbing material were visually confirmed. The results are shown in Table 1.

As shown in Table 1, end wear and adhesion peeling of the sound absorbing material occurred significantly in the tire of Comparative Example 1, but end wear and adhesion peeling of the sound absorbing material occurred in the tires of Example 1 and Reference Examples 1 to 3. Was not recognized at all.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Bead part 3 Side wall part 4 Tire inner surface 5 Adhesive layer 6 Sound-absorbing material 6a, 6b End surface 7 Cavity part

Claims (6)

An annular tread portion extending in the tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the sidewall portions. And a pneumatic tire in which a band-shaped sound absorbing material is bonded to a region corresponding to the tread portion of the tire inner surface via an adhesive layer along the tire circumferential direction. The sound absorbing material is divided at a plurality of locations in the tire circumferential direction. It is composed of a plurality of divided pieces, with substantially arranged to form a single column the sound-absorbing material over the entire circumferential direction of the tire, the sound absorbing material pair of which is disposed at the same position in the tire circumferential direction A pneumatic tire characterized in that the pair of end faces are arranged at positions shifted in the tire width direction so that the end faces do not contact each other.   The pneumatic tire according to claim 1, wherein the sound absorbing material is arranged so as to extend linearly at a certain angle with respect to a tire circumferential direction.   The pneumatic tire according to claim 1, wherein the sound absorbing material is arranged so as to meander along the tire circumferential direction. The pneumatic tire according to any one of claims 1 to 3 , wherein a ratio of a volume of the sound absorbing material to a volume of a hollow portion formed in the tire when the rim is assembled is larger than 20%. The hardness of the sound absorbing material is 60N～170N, pneumatic tire according to any one of claims 1 to 4 tensile strength of the sound absorbing material characterized in that it is a 60KPa～180kPa. The pneumatic tire according to any one of claims 1 to 5 , wherein the adhesive layer is made of a double-sided adhesive tape, and the peel adhesive strength thereof is in the range of 8N / 20mm to 40N / 20mm.

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