JP4855972B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that absorbs and attenuates vibration input from a road surface to reduce road noise in a vehicle interior.

  Conventionally, road noise based on tires has occupied a large proportion as vehicle interior noise during vehicle travel, and vibration input due to road surface irregularities vibrates the tire, and that vibration causes vehicle suspension systems such as wheels, axles, and suspensions. Is recognized as vibration noise in the passenger compartment.

  To reduce road noise, improve tread pattern, increase tread rubber thickness and use soft rubber with excellent vibration absorption for tread to reduce road surface input or change tire vibration transmission characteristics to change wheel and suspension. It has been attempted to reduce road noise by avoiding resonance with the system.

For example, as a method of changing the vibration transmission characteristics in the side portion of the tire, a tire (such as Patent Document 1) equipped with a carcass folding structure and a sidewall reinforcing layer, the tread side from the position of the maximum cross-sectional width of the side rubber surface Or tires provided with an annular convex rubber on the bead side (Patent Documents 2, 3, etc.), and convex parts intermittently arranged in parallel in the circumferential direction of the buttress part are shifted in the tire circumferential direction and arranged alternately. Many techniques have been proposed, such as a tire (Patent Document 4).
JP 2001-71715 A JP-A-9-109621 JP-A-9-109622 JP 2001-130223 A

  However, improvements in the tread pattern, increase in tread rubber thickness, and soft rubber with excellent vibration absorption, and changes in tread structure and members, will improve tire running performance such as handling stability and ride comfort. In many cases, the impact and wear resistance are sacrificed, and the method of changing the vibration transmission characteristics of the side part is sufficient to reduce road noise because the actual vibration transmission characteristics during tire rolling change according to the road surface. In some cases, the above effect could not be obtained.

  Accordingly, an object of the present invention is to provide a pneumatic tire capable of effectively reducing road noise without impairing tire running performance such as steering stability and riding comfort, wear resistance, and the like.

  As a result of diligent studies to solve the above-mentioned problems, the present inventor can relieve and absorb the vibration input in the tire radial direction at the side wall portion that is the vibration transmission path, particularly at the position where the vibration occurs. The present inventors have found that road noise can be reduced while maintaining various performances of a tire by arranging a laminated structure made of an annular plate material.

  That is, the pneumatic tire of the present invention includes a bead portion including a pair of bead cores, a sidewall portion extending outward in the tire radial direction from the bead portion, and a tread portion provided between the sidewall portions. A belt comprising a carcass in which at least one layer of carcass ply is folded back around the pair of bead cores and bead fillers from the inside of the tire to the outside of the tire, and at least two layers of belt ply on the outer peripheral side of the tread portion of the carcass A plurality of annular plate materials and rubber materials at the bead portion on the outer side in the tire radial direction of the carcass between the tire maximum width position and the rim flange contact position within the bead filler arrangement region. And a laminated structure member laminated alternately and is embedded.

  In the pneumatic tire of the present invention, a plurality of annular plate materials and rubber materials are alternately arranged on the buttress portion on the outer side in the tire radial direction of the carcass between the outer ends of both ends of the belt and the tire maximum width position. It is possible to embed a laminated structure member arranged in a layer.

In the present invention, the plate material preferably has a longitudinal elastic modulus in a range of 10 to 25,000 kgf / mm ² .

  Further, it is effective that the arrangement angle of the plate material in the tire radial direction is in a range of 0 ± 20 ° with respect to a vertical line lowered from the tire rotation axis to the ground contact surface.

  Further, in the pneumatic tire according to the present invention, at least one carcass ply of the carcass is divided on the circumference of the tire at the position of the laminated structural member, and the carcass ply divided end portion is annular on the tire circumference. It can be sandwiched between the gaps between the plate materials.

  According to the pneumatic tire of the present invention, the laminated structure member having a laminated structure embedded in the bead portion is deformed in the tire longitudinal direction between the plate members, and the vibration input to the tire from the unevenness of the road surface is reduced and absorbed. As a result, the vibration transmission characteristics can be improved and road noise can be effectively reduced. Furthermore, the effect of reducing road noise can be enhanced by disposing the laminated structural member also in the buttress portion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a half-sectional view showing a pneumatic tire for passenger cars (hereinafter, the pneumatic tire may be simply referred to as “tire”) 1 according to an embodiment of the present invention. FIG. 2 is a bead portion of the tire 1 in FIG. 1, and FIG. 3 is an enlarged partial cross-sectional view of the buttress portion.

  The pneumatic tire 1 is grounded on a road surface provided between a pair of bead portions 4 that are assembled into a rim, a sidewall portion 3 that extends outward in the tire radial direction from the bead portion 4, and the sidewall portions 3, 3. And the tread portion 2 that is configured. The basic structure of the tire 1 is the same as the tire 40 having the conventional general structure shown in FIG.

  As shown in FIG. 1, the tire 1 includes two pairs of carcass plies 61 and 62 made of organic fiber cords such as polyester and rayon extending at an angle of about 90 ° with respect to the tire equator line CL. The carcass 6 is folded around the bead core 5 and the bead filler 9 from the inner side to the outer side of the tire and the bead filler 9 is sandwiched between the bead core 9 and the bead filler 9. A belt 7 composed of at least two layers of crossed belt plies using steel cords, aramid fibers, etc. extending at an angle of angle, and the outer periphery of the belt 7 is spiral at an angle of approximately 0 ° with respect to the tire circumferential direction. A tire for a passenger car having a radial structure having a cap ply 8 made of a wound organic fiber cord such as nylon. Ribs on the tread surface depending on the required performance and the operating conditions of Ya, various tread patterns such block is formed.

  The tire 1 includes a plurality (3 in the figure) of bead portions 4 on the outer side in the tire radial direction of the carcass 6 between the tire maximum width position W and the rim flange contact position R within the arrangement region of the bead fillers 9 on both sides of the tire. A laminated structural member 10 in which annular plate materials 11 and rubber materials are alternately arranged and laminated is embedded.

  As shown in the front view and the side view of the plate material 11 in FIG. 3, the laminated structural member 10 includes a plate material 11 having a circular cross-section that is continuous in the circumferential direction, and a plurality of the plate material 11 and the plate material 11. It is a laminated structure in which rubber materials are alternately arranged and laminated.

  The dimensions of the plate material 11, the rubber thickness between the plate materials 11, the number of laminated layers, and the like are not particularly limited, and can be appropriately determined depending on the tire size, the cross-sectional shape of the buttress portion, the rubber thickness, and the like.

  For example, in the case of a passenger car tire, the thickness W of the plate material 11 is 0.1 to 2.0 mm, preferably 0.2 to 1.5 mm. If the thickness W is too thin, the plate material will be flexible and the required vertical and lateral rigidity will not be obtained, and if it is too thick, it will be difficult to ensure steering stability and ride comfort due to high rigidity in both the vertical and horizontal directions. Further, the dynamic adhesiveness is lowered due to the difference in rigidity with the adjacent rubber material. Further, the plate width H and the outer diameter D are appropriately determined depending on the tire size, required characteristics, etc. For example, the ratio of the plate thickness W to the width H is about H / W = 5 to 30, and H / W = 8. A range of ˜20 is more preferred. The upper limit of the number of stacked sheets is not particularly limited, but is about 10 in the case of passenger car tires.

  As shown in FIG. 5, the plate material 11 has a plurality of plates in which the outer diameter D and the inner diameter d are gradually reduced in accordance with the cross-sectional shape of the bead portion 4 (in the drawing, four 11 a to 11 d are shown). Are stacked in parallel in a stepped manner with gaps S1, S2 and S3 between them. In the vulcanized tire, each of the gaps S is filled with a rubber material, and a plurality of plate members 11 are bonded to each other to form a laminated structural member 10 and the laminated structural member 10 is embedded and fixed in the rubber of the bead portion 4. The The distance between the gaps S1, S2, and S3 is not particularly limited, but is, for example, about 0.2 to 3.0 mm, preferably 0.2 to 2.0 mm. If the distance between the gaps S is small, sufficient displacement between adjacent plate materials cannot be obtained, and the amount of deformation in the longitudinal direction of the laminated structural member 10 is particularly small, making it difficult to alleviate and absorb vibration. Further, when the gap S is widened, the displacement between the plate members 11 is increased, and there is a possibility that the displacement is likely to vary especially when the oblique input is performed, and the steering stability may be lowered. There is a risk of lowering the durability. The distances between the gaps S1 and S2 may be equal or different.

  The laminated structural member 10 can be formed by laminating a plurality of plate materials 11 and sheet-like rubber materials alternately on the buttress portion 4 during tire molding.

  The laminated structure member 10 is formed in advance with a molded body formed by alternately laminating a plurality of annular plate materials 11 and a plurality of sheet-like rubber materials, and this molded body is disposed in the bead portion 4 at the time of tire molding. You can also

  When the vibration from the road surface unevenness is input to the tire 1 in the longitudinal direction of the tire, the laminated structural member 10 is deformed in the lateral direction by each of the laminated plate materials 11 being gradually displaced in the longitudinal direction. It is possible to reduce and absorb only the vibration in the vertical direction without occurring, improve the vibration transmission characteristic, and reduce the road noise.

  Further, the tire 1 includes a buttress portion B positioned between the outer side in the tire axial direction and the maximum width portion W of the tire that is disengaged from the belt end portions 7a on both sides of the belt 7, and the buttress portion B on the outer side in the tire radial direction of the carcass 6. Further, a laminated structure member 20 in which a plurality of annular plate materials 21 similar to those buried in the bead portion 4 are laminated is embedded.

  Since the structure of the laminated structural member 20 and the shape of the plate material 21 are the same as those shown in FIGS. 4 and 5, the description thereof is omitted here.

  The laminated structural member 20 can be formed by laminating a plurality of plate materials 21 and sheet-like rubber materials alternately on the buttress portion B during tire molding.

  Further, the laminated structural member 20 is formed in advance with a molded body formed by alternately laminating a plurality of annular plate materials 21 and a plurality of sheet-like rubber materials, and this molded body is disposed in the buttress portion B at the time of tire molding. You can also

  Similarly to the laminated structural member 10 embedded in the bead portion 4, the laminated structural member 20 also has the laminated plate member 21 when the vibration from the road surface unevenness is input to the tire 1 in the tire longitudinal direction. By gradual displacement in the vertical direction, only the vibration in the vertical direction is mitigated and absorbed without causing deformation in the horizontal direction, the vibration transmission characteristics are improved, and a synergistic effect with the laminated structure member 10 is achieved. Noise can be reduced more effectively.

  It is known that the tire vibration mode is a mode in which the maximum width position of the belt end portion and the side portion and the bead fixing portion are nodes, and the radially outer portion of the buttress portion and the bead portion has a belly. Therefore, the present invention can reduce the vibration transmission characteristics of the tire by suppressing or adjusting the amplitude of the vibration mode of the radially outer portion of the bead portion. The structure member is arranged, and the effect can be improved by arranging a similar structure member in the buttress portion.

  In this way, road noise can be reduced because the vibration mode itself has been changed. However, qualitatively, the amplitude of the portion having vibration antinodes is reduced, and the natural frequency is further reduced. It can be explained that the overall energy level could be lowered.

  Further, the laminated structural member 20 is configured such that when an external force in the vertical direction, the horizontal direction, or both directions is input to the tire 1, the stacked plate material 21 is displaced stepwise in both the vertical and horizontal directions. The longitudinal and lateral stiffnesses can be controlled independently. In particular, by making it easy to cause displacement with respect to longitudinal input, the tire is flexible with respect to longitudinal deflection (input) and rigid with respect to lateral deflection (input). It also has the effect of balancing the handling stability and ride comfort.

The material of the plate materials 11 and 21 is not particularly limited, but those having a longitudinal elastic modulus (Young's modulus) of 10 to 25,000 kgf / mm ² are preferable, and 1,000 to 25 are particularly preferable. Those in the range of 1,000 kgf / mm ² are preferred.

  Examples of the material of the plate materials 11 and 21 in the range of the Young's modulus include metals such as carbon steel, stainless steel, alloy steel such as molybdenum, nickel, and chromium, soft iron, aluminum, aluminum alloy, copper, and lead. It is done.

  Further, as resins, polyamide resins (nylon 6, nylon 66, etc.), polyester resins (PET, PBN, PEN, etc.), polynitrile resins (PAN, AS, etc.), poly (meth) acrylate resins (PMMA, EEA) Etc.), polyvinyl resins (EVA, PVA, PVC, etc.), cellulose resins (cellulose acetate, etc.), fluororesins (polyvinylidene fluoride, polyvinyl fluoride, etc.), thermoplastic resins, styrene, olefin, Examples thereof include thermoplastic elastomers such as polyester, urethane, and polyamide, and a blend material of these plural resins may be used.

  In addition, thermosetting resins such as urea resins, epoxy resins, and phenol resins can be used.

  Further, the resin may be a metal filament such as stainless steel or a reinforced plastic (MRP or FRP) reinforced with organic or inorganic fibers such as nylon, PET, glass fiber, or carbon fiber.

  The laminated structural members 10 and 20 may be formed by combining the plate materials made of the above two or more kinds of materials.

  The surfaces of the plate materials 11 and 21 are for the purpose of improving the adhesiveness to rubber, physical surface treatment by polishing or blasting, application of adhesives such as various rubber pastes and resorcin-formaldehyde-latex liquid, brass, etc. It is preferable to perform metal plating treatment of zinc or zinc.

Here, it is preferable that the plate materials 11 and 21 and the rubber material disposed in the gap S have a larger difference between their Young's moduli. Accordingly, the plate members 11 and 21 are easily displaced between the layers of the laminated structural members 10 and 20 with respect to the input applied to the tire 1, and as a result, the laminated structural members 10 and 20 are easily bent in the tire radial direction and road noise. It becomes easy to obtain improvement. Since the Young's modulus of the vulcanized rubber material for tires is generally in the range of 0.1 to 0.5 kgf / mm ² , the Young's modulus of the plate materials 11 and 21 is 1,000 kgf / mm ² or more from this viewpoint. It is preferable that it exists in. When the Young's modulus is less than 10 kgf / mm ^2, the laminated structure member 11 moves assimilating to the movement of the rubber of the buttress portion 10 and the effect of the present invention cannot be sufficiently obtained.

  In addition, the arrangement angle in the tire radial direction of the annular plate members 11 and 21 in the laminated structural members 10 and 20 uses a standard rim defined by JIS, and from the tire rotation axis to the ground contact surface when a specified internal pressure and a maximum load are applied. It is preferable to arrange in the range of 0 ± 20 ° with respect to the lowered vertical line.

  When the arrangement angle of the plate members 11 and 21 is out of the range of ± 20 ° with respect to the vertical line, the vibration input to the tire 1 is inclined with respect to the laminated structural members 10 and 20, There is a possibility that the input balance to the structural members 10 and 20 is lost, the vibration transmission characteristics are deteriorated, and road noise is increased. Furthermore, the rigidity balance between the vertical direction and the horizontal direction of the bead part 4 and the buttress part B is lost, and there is a possibility that steering stability and riding comfort are lowered.

  However, as for the arrangement angle of the plate material 21 arranged in the buttress portion B, when the inclination angle is increased, the damping performance with respect to the longitudinal input of the laminated structural member 20 is lowered, and it is difficult to obtain the balance between the longitudinal rigidity and the lateral rigidity of the tire 1. Therefore, the range of 0 ± 10 ° is more preferable.

  In the present invention, as in the tire 30 shown in FIG. 6, at least one carcass ply of the carcass 6 is divided on the tire circumference at the position of the laminated structural member 20 of the buttress portion B, and the carcass ply split end is provided. The portion may be sandwiched in the gap S between the annular plate members 21 of the laminated structural member 20 on the tire circumference.

  The tire 30 is a tire in which the carcass 6 has a two-ply structure, and in the carcass ply, the 2nd ply 62 is divided on the tire circumference at the position of the laminated structural member 20 on both sides of the tire, and the ply is divided on the tread 2 side. The end 62a is sandwiched between the plate members 21b and 21c on the tire circumference, and the ply split end 62b on the side wall 3 side is sandwiched between the plate members 21c and 21d, and the carcass is interposed via the plate member 12c. 6 2nd plies 62 are integrally formed. In the example shown in the figure, the 1st ply 61 continuously forms a carcass without being divided, but the 1st ply 61 can also have a divided structure in the same manner as the 2nd ply.

  By dividing the carcass ply at the site of the laminated structural member 11 in this manner, the amount of deformation in the vertical direction of the buttress portion B is increased, thereby improving vibration relaxation and absorption, and further improving riding comfort. It is also possible.

  Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to the examples.

Laminated structure member in which the tire size is 215 / 60R16 (rib pattern of 4 main grooves), and a 0.5 mm thick rubber material is alternately arranged between three 0.5 mm thick plate materials to form a laminated structure Tires of Examples 1 to 3 and 7 embedded in the bead portion, and tires of Examples 4 to 6 in which the laminated structural members were embedded in the bead portion and the buttress portion (laminated structure of four plate members) were made as trial products. Table 1 shows the plate materials used in each example. As the plate material, carbon 0.33% carbon steel plate (Young's modulus 210,000 kgf / mm ² ), aluminum alloy (Young's modulus 1,100 kgf / mm ² ) and nylon 6 resin (Young's modulus 110 kgf / mm ² ) plate are used. The combinations described in Table 1 were used. In the tires of Example 7 and Comparative Example 2, the plate material arrangement angle of the laminated structure member embedded in the bead portion is arranged at an inclination angle of 15 ° or 23 ° on the inner side in the tire axial direction (carcass 6 side). did. The tire of Comparative Example 1 is a tire having a conventional structure shown in FIG. The vibration transfer characteristics of each prototype tire were measured under the following conditions.

  Under the conditions of use rim 16 × 6.5 JJ, air pressure 200 kPa, longitudinal load 480 kgf, a vibration input is applied to the tread center in the tire radial direction, and the vibration transmission characteristics in the tire side part are response levels at a frequency of 0 to 500 Hz. The sum (dB) was measured, and the difference was shown in Table 1 with the tire of Comparative Example 1 as a reference.

  FIG. 8 illustrates vibration transmission characteristics (waveform of frequency response level (dB)) in the tire side maximum width portion at frequencies of 0 to 500 Hz in Examples 1, 2, and 4. Example 1 is indicated by a one-dot chain line, Example 2 is indicated by a thin solid line, Example 4 is indicated by a thick solid line, and Comparative Example 1 is indicated by a broken line.

  The carcass of each tire is 2 plies of polyester cord 1100 dtex / 2 (drive density 23/25 mm), the belt is steel cord 2 + 2 × 0.25 mm (drive density 25/25 mm), 2 plies, and the cap ply is nylon 66 One ply with a cord of 940 dtex / 2 (injection density of 21/25 mm) was used, and the example and the comparative example were the same.

  As shown in Table 1, with respect to the tire of Comparative Example 1, each example tire has a small sum of response levels at a frequency of 0 to 500 Hz, and vibration transmission at the tire side portion is reduced, which is effective in reducing road noise. I know that there is.

  The present invention can be applied to pneumatic tires for various sizes and uses such as for passenger cars, light trucks, large tires for buses and trucks.

It is a half sectional view of the pneumatic tire of an embodiment. It is an expanded sectional view of a bead part of a tire same as the above. It is an expanded sectional view of the buttress part of a tire same as the above. It is the front view and side view of a plate material. It is a side view of a laminated structure member. It is an expanded sectional view of the buttress part of the tire of other embodiments. It is a half sectional view of a pneumatic tire of a conventional example. It is a graph which illustrates the vibration transmission characteristic of a tire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pneumatic tire 2 ... Tread part 3 ... Side wall part 4 ... Bead part 5 ... Bead core 6 ... Carcass 7 ... Belt 10 ... Laminated structural member 11 ... Plate material R ... Rim flange Contact position W: Maximum width of tire

Claims (5)

A bead portion having a pair of bead cores, a sidewall portion extending outward in the tire radial direction from the bead portion, and a tread portion provided between the sidewall portions, wherein at least one layer of the carcass ply is In a pneumatic tire in which a carcass in which a pair of bead cores and bead fillers are folded and locked from the inside of the tire to the outside of the tire and a belt composed of at least two layers of belt plies are arranged on the outer peripheral side of the tread portion of the carcass,
In the bead filler arrangement region, a plurality of annular plate materials and rubber materials are alternately arranged and stacked on the bead portion on the outer side in the tire radial direction of the carcass between the tire maximum width position and the rim flange contact position. A pneumatic tire characterized in that the laminated structural member is embedded. Further, a laminated structure member in which a plurality of annular plate materials and rubber materials are alternately arranged and laminated on the buttress portion on the outer side in the tire radial direction of the carcass between the outer ends of both ends of the belt and the tire maximum width position. The pneumatic tire according to claim 1, wherein the pneumatic tire is embedded. The pneumatic tire according to claim 1 or 2, wherein the plate material has a longitudinal elastic modulus in a range of 10 to 25,000 kgf / mm ² . The arrangement angle in the tire radial direction of the plate material is in a range of 0 ± 20 ° with respect to a vertical line that is lowered from the tire rotation axis to the ground contact surface. Pneumatic tires. At least one carcass ply of the carcass is divided on the tire circumference at the position of the laminated structure member of the buttress portion, and the carcass ply divided end portion is sandwiched between the annular plate members on the tire circumference. The pneumatic tire according to claim 2, wherein the pneumatic tire is a tire.

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