JP2013169826A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving noise performance.SOLUTION: A pneumatic tire 1 includes: a carcass layer 13; a pair of cross belts 141, 142 disposed at the tire radial direction outside of the carcass layer 13; and rubber layers (tread rubber 15 and sidewall rubber 16) configuring a tread portion and sidewall portions by covering the carcass layer 13 and the pair of cross belts 141, 142. The pneumatic tire 1 includes damping members 2 each including a continuous foaming body 21, disposed outside the carcass layer 13 and inside the rubber layers 15, 16 and extending in a tire circumferential direction.

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that can improve noise performance.

  With recent pneumatic tires, there is a need to reduce road noise as vehicles become more sophisticated and quieter. This road noise is generated when vibration is transmitted from the tire ground contact surface to the vehicle interior. As a conventional pneumatic tire related to this problem, a technique described in Patent Document 1 is known.

JP 2000-127709 A

  An object of the present invention is to provide a pneumatic tire capable of improving noise performance.

  In order to achieve the above object, a pneumatic tire according to the present invention covers a carcass layer, a pair of cross belts arranged on the outer side in the tire radial direction of the carcass layer, and the carcass layer and the pair of cross belts. A pneumatic tire comprising a tread portion and a rubber layer constituting a sidewall portion, having a continuous foam, and being disposed outside the carcass layer and inside the rubber layer and extending in the tire circumferential direction A damping member is provided.

  In the pneumatic tire according to the present invention, the vibration transmitted from the tread portion to the sidewall portion at the time of rolling of the tire is obtained by disposing the damping member having the continuous foam embedded in the tire. It is attenuated and absorbed. Thereby, there is an advantage that road noise is reduced and the noise performance of the tire is improved.

FIG. 1 is a sectional view in the tire meridian direction showing a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a vibration damping member of the pneumatic tire depicted in FIG. FIG. 3 is an explanatory view showing the operation of the vibration damping member shown in FIG. FIG. 4 is an explanatory view showing a modified example of the pneumatic tire shown in FIG. 1. FIG. 5 is an explanatory view showing a modified example of the pneumatic tire shown in FIG. 1. FIG. 6 is an explanatory view showing a modified example of the pneumatic tire shown in FIG. 1. FIG. 7 is an explanatory view showing a modified example of the pneumatic tire shown in FIG. 1. FIG. 8 is a chart showing the results of the performance test of the pneumatic tire according to the embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Further, the constituent elements of this embodiment include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Pneumatic tire]
FIG. 1 is a sectional view in the tire meridian direction showing a pneumatic tire 1 according to an embodiment of the present invention. The figure shows a radial tire for a passenger car as an example of the pneumatic tire 1. Reference sign CL is a tire equator plane.

  The pneumatic tire 1 includes a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, a pair of sidewall rubbers 16, 16, and a pair. Bead rubbers 17 and 17 (see FIG. 1).

  The pair of bead cores 11 and 11 has an annular structure and constitutes the core of the left and right bead portions. The pair of bead fillers 12 and 12 are disposed on the outer periphery in the tire radial direction of the pair of bead cores 11 and 11 to reinforce the bead portion.

  The carcass layer 13 has a single-layer structure and is bridged in a toroidal shape between the left and right bead cores 11 and 11 to constitute a tire skeleton. Further, both end portions of the carcass layer 13 are wound and locked outward in the tire width direction so as to wrap the bead core 11 and the bead filler 12. The carcass layer 13 is formed by coating a plurality of carcass cords made of steel or an organic fiber material (for example, nylon, polyester, rayon, etc.) with a coating rubber and rolling them, and has an absolute value of 85 [deg] or more and 95. [Deg] The following carcass angle (inclination angle in the fiber direction of the carcass cord with respect to the tire circumferential direction).

  The belt layer 14 is formed by laminating a pair of cross belts 141 and 142 and a belt cover 143, and is arranged around the outer periphery of the carcass layer 13. The pair of cross belts 141 and 142 is formed by rolling a plurality of belt cords made of steel or organic fiber material with a coating rubber, and having a belt angle of 10 [deg] or more and 30 [deg] or less in absolute value. Have. Further, the pair of cross belts 141 and 142 have belt angles with different signs from each other (inclination angle of the fiber direction of the belt cord with respect to the tire circumferential direction), and are laminated so that the fiber directions of the belt cords cross each other. (Cross ply structure). The belt cover 143 is formed by rolling a plurality of belt cords made of steel or organic fiber material with a coat rubber, and has a belt angle of 10 [deg] or more and 45 [deg] or less in absolute value. Further, the belt cover 143 is disposed so as to be laminated on the outer side in the tire radial direction of the cross belts 141 and 142.

  The tread rubber 15 is disposed on the outer circumference in the tire radial direction of the carcass layer 13 and the belt layer 14 to constitute a tread portion of the tire. The pair of side wall rubbers 16 and 16 are respectively arranged on the outer side in the tire width direction of the carcass layer 13 to constitute left and right side wall portions. The pair of bead rubbers 17, 17 are arranged on the outer sides in the tire width direction of the left and right bead cores 11, 11 and the bead fillers 12, 12 to constitute left and right bead portions.

[Vibration control member]
FIG. 2 is a cross-sectional view showing the vibration damping member 2 of the pneumatic tire 1 shown in FIG. FIG. 3 is an explanatory view showing the operation of the vibration damping member 2 shown in FIG. In these drawings, FIG. 2 shows a radial cross-sectional view of a single damping member 2, and FIG. 3 shows a state in which the pneumatic tire 1 is viewed from the side when the vehicle is running.

  As shown in FIG. 1, the pneumatic tire 1 includes a vibration damping member 2.

  The damping member 2 is a member for reducing road noise, and includes a continuous foam 21, a seal layer 22, and a reinforcing layer 23 as shown in FIG. 2.

  The continuous foam 21 is a member having cellular cells communicated with each other, and is made of, for example, polyurethane foam. The continuous foam 21 has characteristics different from those of the independent foam in that gas or liquid can be permeated. In the configuration of FIG. 2, the continuous foam 21 is an annular member having a solid circular cross section, and constitutes the core of the vibration damping member 2.

  The seal layer 22 is a layer that covers the outer periphery of the continuous foam 21 and suppresses the intrusion of liquid (for example, chemicals of rubber material, water, oil, etc.) from the outside to the continuous foam 21. Made of synthetic resin. In the configuration of FIG. 2, the sealing layer 22 is disposed by coating the continuous foam 21 into a film shape.

  The reinforcing layer 23 is a layer that covers the outer periphery of the continuous foam 21 and reinforces the continuous foam 21 and is made of, for example, organic fibers such as nylon fibers. In the configuration of FIG. 2, the reinforcing layer 23 has a tubular structure formed by weaving organic fibers in a mesh shape, and is disposed so as to enclose the continuous foam 21 and the sealing layer 22. Since the reinforcing layer 23 can be flexibly deformed while maintaining its cross-sectional shape, it is preferable in that it can be deformed following tire deformation without crushing the internal continuous foam 21 during rolling of the tire.

  Further, as shown in FIG. 1, the damping member 2 is disposed outside the carcass layer 13 and inside the rubber layer (tread rubber 15 and sidewall rubber 16) and extends in the tire circumferential direction. That is, the damping member 2 is embedded and arranged inside the tire without being exposed on the tire surface.

  Here, the distance from the tire equatorial plane CL to the outer end in the tire width direction of the wide cross belt 141 of the pair of cross belts 141 and 142 is defined as Wb (see FIG. 1). At this time, it is preferable that the damping member 2 is disposed in a region A from the position of the distance Wb × (2/3) starting from the tire equatorial plane CL to the tire maximum width position P.

  For example, in the configuration of FIG. 1, the pair of vibration damping members 2, 2 are respectively disposed on the left and right buttress portions (connection portion between the tread portion and the sidewall portion) of the tire. Further, each damping member 2, 2 is on the outer side in the tire width direction than the belt layer 14, and is disposed between the tread rubber 15 and the sidewall rubber 16. Further, as shown in FIG. 3, each damping member 2 has an annular structure and is disposed so as to surround the outer periphery of the carcass layer 13. The vibration damping member 2 may be disposed on at least one of the right and left buttress portions of the tire.

  In the pneumatic tire 1, the vibration damping member 2 attenuates and absorbs vibration transmitted from the tread portion to the sidewall portion when the tire rolls (see FIG. 3). Specifically, the vibration is transmitted to the air inside the continuous foam 21, and the air moves inside the continuous foam 21, so that the vibration is converted into heat energy and attenuated due to the viscosity of the air. Thereby, the medium frequency noise of 250 [Hz] to 400 [Hz] is effectively suppressed.

[Modification]
4-7 is explanatory drawing which shows the modification of the pneumatic tire 1 described in FIG. In these drawings, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In the configuration of FIG. 1, as described above, the damping members 2, 2 are located on the outer side in the tire width direction than the belt layer 14 and are sandwiched between the tread rubber 15 and the sidewall rubber 16. ing. Such a configuration is preferable in that the step of arranging the damping member 2 in the green tire molding step can be facilitated.

  However, the present invention is not limited to this, and the damping members 2 and 2 may be disposed between the belt layer 14 and the tread rubber 15 on the outer side in the tire radial direction of the belt layer 14 (a), (B) It may be disposed between the carcass layer 13 and the sidewall rubber 16 (not shown). Further, (c) the damping members 2 and 2 may be embedded in the tread rubber 15 or the sidewall rubber 16 (not shown).

  Further, in the configuration of FIG. 2, as described above, the sealing layer 22 is coated on the continuous foam 21 serving as the core, and the damping layer 2 is configured by covering the sealing layer 22 with the reinforcing layer 23. . With such a configuration, the sealing layer 22 is directly coated on the continuous foam 21, which is preferable in that the sealing action by the sealing layer 22 is improved.

  However, the present invention is not limited to this, and the vibration damping member 2 may be configured by covering the continuous foam 21 with the reinforcing layer 23 and coating the reinforcing layer 23 with the seal layer 22 (not shown). Even with this configuration, the sealing action by the sealing layer 22 and the reinforcing action by the reinforcing layer 23 can be appropriately obtained.

  Further, the configuration is not limited to this, and a configuration in which the seal layer 22 is omitted from the vibration damping member 2 in FIG. 2 may be employed, or a configuration in which the reinforcing layer 23 is omitted may be employed (not illustrated). Therefore, the damping member 2 should just have the continuous foam 21 at least. Thereby, the vibration damping action by the continuous foam 21 is ensured.

  In the configuration of FIG. 2, as described above, the damping member 2 has a uniform circular cross section. However, the present invention is not limited to this, and the damping member 2 may have a polygonal cross section such as a uniform quadrangular cross section, a hexagonal cross section, an octagonal cross section, an elliptical cross section, a semicircular cross section, etc. You may have (illustration omitted). Moreover, as shown in FIG. 4, the damping member 2 may have a wide rectangular cross section.

  Here, when the damping member 2 has a point-symmetric cross-sectional shape as shown in FIG. 2, the outer diameter D of the damping member 2 is in the range of 5 [mm] ≦ D ≦ 20 [mm]. It is preferable (see FIG. 2). By setting 5 [mm] ≦ D, the vibration damping member 2 can be easily manufactured, and the vibration damping action by the vibration damping member 2 can be appropriately obtained. In addition, by setting D ≦ 20 [mm], it is possible to reduce the influence on the tire rigidity due to the arrangement of the damping member 2 (continuous foam 21).

  On the other hand, in the configuration in which the damping member 2 has a wide cross-sectional shape as shown in FIG. 4, the damping member 2 is arranged with the long side along the carcass layer 13 (not shown). At this time, the width W of the long side of the damping member 2 is preferably in the range of W ≦ 10 [mm], and the height H of the damping member 2 is 2 [mm] ≦ H ≦ 5 [ mm]. Thereby, the vibration damping action by the damping member 2 can be appropriately obtained, and the influence on the tire rigidity due to the arrangement of the damping member 2 can be reduced.

  Moreover, in the structure of FIG. 1, the damping member 2 is arrange | positioned 1 each at the buttress part of the tire right and left. However, the present invention is not limited to this, and a plurality of vibration damping members 2 may be disposed in the buttress portions on the left and right sides of the tire (not shown). Further, for example, as shown in FIG. 5, a plurality of vibration damping members 2 ′ having a small diameter may be disposed around the vibration damping member 2 having a large diameter. For example, the two damping members 2 and 2 may be arranged adjacent to each other. At this time, the distance g between the adjacent damping members 2 and 2 is preferably in the range of 1.3 [mm] ≦ g, and more preferably in the range of 1.7 [mm] ≦ g. Thereby, the influence of the tire rigidity fall by arrangement | positioning of the damping member 2 can be reduced, and the fracture | rupture of the damping member 2 by friction can be suppressed.

  Further, in the configuration of FIG. 3, the damping member 2 has an annular structure (ring shape) and is fitted and disposed in the buttress portion. Therefore, the damping member 2 is continuous in the tire circumferential direction and is disposed over the entire circumference of the tire. Such a configuration is preferable in that the vibration damping member 2 is continuous in the tire circumferential direction, whereby the air flow in the continuous foam 21 is improved and the vibration damping effect of the continuous foam 21 is improved.

  However, the present invention is not limited to this, and as shown in FIGS. 6 and 7, the vibration damping member 2 may have a long structure and be wound around the tire circumferential direction. For example, in the configuration of FIG. 6, one damping member 2 is arranged over the entire circumference of the tire by circling the tire and wrapping both ends. Further, in the configuration of FIG. 7, the pair of damping members 2 are arranged over the entire circumference of the tire by wrapping both ends. Even with such a configuration, the vibration damping action by the continuous foam 21 can be obtained. In addition, the damping member 2 can be easily installed as compared with a configuration in which the damping member 2 has an annular structure.

  At this time, it is preferable that the length L of the damping member 2 and the tire ground contact length La (not shown) have a relationship of 2.0 ≦ L / La. Thereby, the length L of the damping member 2 is ensured, and the vibration damping action by the continuous foam 21 is ensured appropriately.

  The tire contact length La is the tire when the tire is attached to the specified rim and applied with the specified internal pressure, and is placed perpendicular to the flat plate in a stationary state and applied with a load corresponding to the specified load. It is measured at the contact surface with the flat plate.

  Here, the prescribed rim refers to “applied rim” prescribed in JATMA, “Design Rim” prescribed in TRA, or “Measuring Rim” prescribed in ETRTO. The specified internal pressure means “maximum air pressure” specified by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” specified by TRA, or “INFLATION PRESSURES” specified by ETRTO. The specified load means the “maximum load capacity” defined by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO. However, in JATMA, in the case of tires for passenger cars, the specified internal pressure is air pressure 180 [kPa], and the specified load is 88 [%] of the maximum load capacity.

[effect]
As described above, the pneumatic tire 1 includes the carcass layer 13, the pair of cross belts 141 and 142 disposed on the outer side in the tire radial direction of the carcass layer 13, and the carcass layer 13 and the pair of cross belts 141 and 142. And a rubber layer (tread rubber 15 and sidewall rubber 16) constituting a tread portion and a sidewall portion. The pneumatic tire 1 includes a continuous foam 21 and includes a vibration damping member 2 that is disposed outside the carcass layer 13 and inside the rubber layers 15 and 16 and extends in the tire circumferential direction.

  In such a configuration, the vibration-damping member 2 having the continuous foam 21 is embedded and disposed inside the tire, so that vibration transmitted from the tread portion to the sidewall portion at the time of tire rolling is generated in the continuous foam 21. It is attenuated and absorbed (see FIG. 3). Thereby, there is an advantage that road noise is reduced and the noise performance of the tire is improved. Moreover, in this structure, there exists an advantage which can suppress the increase in a tire weight by using the damping member 2 which has the continuous foam 21. FIG.

  In the pneumatic tire 1, the vibration damping member 2 has an annular structure and is disposed so as to surround the outer periphery of the carcass layer 13 (see FIGS. 1 and 3). In such a configuration, since the damping member 2 is arranged over the entire circumference of the tire, there is an advantage that the vibration damping action by the continuous foam 21 can be effectively obtained.

  In the pneumatic tire 1, the damping member 2 has a long structure and is wound around the tire in the circumferential direction (see FIGS. 6 and 7). With this configuration, there is an advantage that the installation process of the damping member 2 is facilitated as compared with the configuration in which the damping member 2 has an annular structure.

  Moreover, this pneumatic tire 1 has the sealing layer 22 in which the damping member 2 covers the outer periphery of the continuous foam 21 (see FIG. 2). In such a configuration, there is an advantage that the continuous foam 21 is appropriately protected by suppressing the intrusion of the liquid into the continuous foam 21 from the outside by the seal layer 22.

  In the pneumatic tire 1, the damping member 2 includes a reinforcing layer 23 that covers the outer periphery of the continuous foam 21 and reinforces the continuous foam 21 (see FIG. 2). In such a configuration, there is an advantage that the vibration damping action by the continuous foam 21 is appropriately ensured by the reinforcing layer 23 securing the shape of the continuous foam 21.

  Further, in this pneumatic tire 1, when the distance from the tire equatorial plane CL to the end of the wide cross belt 141 on the outer side in the tire width direction is Wb, the damping member 2 starts from the tire equatorial plane CL. It arrange | positions in the area | region A from the position of distance Wbx (2/3) to the tire maximum width position P (refer FIG. 1). In such a configuration, the vibration damping member 2 is arranged in the buttress portion, and thus, particularly, there is an advantage that medium frequency noise of 250 [Hz] to 400 [Hz] is effectively suppressed. This is because the vibration that causes the medium frequency noise has a vibration mode in which the end portion of the belt layer 14 and the tire maximum width position P are nodes, and the buttress portion is an antinode.

  FIG. 8 is a chart showing the results of the performance test of the pneumatic tire according to the embodiment of the present invention.

  In this performance test, (1) noise performance and (2) tire weight were evaluated for a plurality of different pneumatic tires (see FIG. 8).

  (1) In the noise performance evaluation, a pneumatic tire having a tire size of 205 / 65R15 is assembled to an applicable rim stipulated by JATMA, and a 200 [kPa] air pressure and a maximum load stipulated by JATMA are applied to the pneumatic tire. A pneumatic tire is mounted on a passenger car having a displacement of 2000 [cc], which is a test vehicle. Then, the test vehicle travels on a test course having a rough road surface at 60 [km / h], and the sound pressure level is measured by a microphone attached to the window side position of the driver's seat. Then, based on the measurement result, index evaluation is performed with the conventional example 1 as a reference (100). In this evaluation, the larger the value, the smaller the road noise, which is preferable.

  (2) In the tire weight evaluation, index evaluation is performed with the conventional example 1 as a reference (100). In this evaluation, the larger the numerical value, the lighter the tire, and the more preferable.

  The pneumatic tires 1 of Examples 1 and 2 have the configurations described in FIGS. 1 to 3 and have vibration damping members 2 on the left and right buttress portions, respectively. Moreover, the damping member 2 has a triple structure composed of the continuous foam 21, the seal layer 22, and the reinforcing layer 23, and has an annular structure as a whole. Further, the continuous foam 21 of the vibration damping member 2 is urethane foam, the seal layer 22 is a polyethylene film, and the reinforcing layer 23 is made of nylon fibers.

  The pneumatic tire of Conventional Example 1 does not have the vibration damping member 2 in the configuration of FIG. The pneumatic tire of Conventional Example 2 has a configuration in which a damping rubber sheet is attached to the inner peripheral surface of the tire instead of the damping member 2 in the configuration of FIG.

  As shown in the test results, in the pneumatic tires 1 of Examples 1 and 2, it can be seen that the noise performance can be improved while reducing the tire weight.

  DESCRIPTION OF SYMBOLS 1 Pneumatic tire, 2 Damping member, 21 Continuous foam, 22 Seal layer, 23 Reinforcement layer, 11 Bead core, 12 Bead filler, 13 Carcass layer, 14 Belt layer, 141, 142 Cross belt, 143 Belt cover, 15 Tread Rubber, 16 side wall rubber, 17 bead rubber

Claims (6)

A pneumatic comprising a carcass layer, a pair of cross belts arranged on the outer side in the tire radial direction of the carcass layer, and a rubber layer that covers the carcass layer and the pair of cross belts and constitutes a tread portion and a sidewall portion Tire,
A pneumatic tire comprising a continuous foam and a vibration damping member disposed outside the carcass layer and inside the rubber layer and extending in a tire circumferential direction.   The pneumatic tire according to claim 1, wherein the damping member has an annular structure and is disposed so as to surround an outer periphery of the carcass layer.   The pneumatic tire according to claim 1, wherein the vibration damping member has a long structure and is wound around the tire circumferential direction.   The pneumatic tire according to claim 1, wherein the vibration damping member has a seal layer that covers an outer periphery of the continuous foam.   The pneumatic tire according to any one of claims 1 to 4, wherein the damping member has a reinforcing layer that covers an outer periphery of the continuous foam to reinforce the continuous foam.   When the distance from the tire equator plane to the outer end in the tire width direction of the wide cross belt of the pair of cross belts is Wb, the vibration damping member is a distance Wb × ( The pneumatic tire according to any one of claims 1 to 5, which is disposed in a region from a position 2/3) to a tire maximum width position.

Images