JP6001514B2 - Pneumatic tire - Google Patents

Description

  The present invention relates to a pneumatic tire.

  Patent Document 1 discloses a pneumatic tire in which a full band is provided on the tire radial direction side of the belt so as to cover the belt, and edge bands are overlapped on both ends of the full band. In this pneumatic tire, by increasing the modulus of the band cord constituting the edge band rather than the band cord constituting the full band, the vibration of the belt end is suppressed and the quietness is improved. Further, by providing the edge band only at the end portion of the full band, it is possible to suppress an increase in the rigidity in the tire circumferential direction of the belt central portion and to improve the riding comfort.

JP 2007-168554 A

In Patent Document 1, high quietness and riding comfort are obtained by the above-described configuration, but there is room for further improvement regarding quietness.
An object of the present invention is to improve quietness while ensuring ride comfort.

The pneumatic tire according to claim 1 of the present invention is rubber-coated with a plurality of belt cords arranged on the outer side in the tire radial direction of the carcass layer forming the tire frame and extending obliquely with respect to the tire circumferential direction. A belt layer formed by a plurality of belt plies formed on the outer side in the tire radial direction of the belt layer, and both end portions in the tire axial direction are respectively more than both end portions in the tire axial direction of the belt layer A first reinforcing layer that is located on the outer side in the tire axial direction and is constituted by at least one first reinforcing ply formed by spirally winding a rubber-coated first reinforcing cord in the tire circumferential direction; superimposed respectively on both end sides in the tire axial direction of the first reinforcing layer, straddles the end of the tire axial direction of the belt ply of the outermost layer, or one prior Symbol the belt layer the said end portion of the first reinforcing layer end Between the first reinforcing layer and the at least one second reinforcing ply formed by spirally winding a rubber-coated second reinforcing cord in the tire circumferential direction. A second reinforcing layer having high rigidity in the direction, and a plurality of rib-shaped land portions provided on a tread disposed on the outer side in the tire radial direction than the belt layer and continuous in the tire circumferential direction. The first land portion disposed on the tire equator plane, the second land portion disposed adjacent to the outer side of the first land portion in the vehicle mounting direction, and the inner side of the first land portion in the vehicle mounting direction. A third land portion disposed adjacent thereto, wherein the first land portion is formed closer to the inside of the tire mounting direction than the tire equator plane, and the width of the second land portion is equal to that of the third land portion. It is formed larger than the width, and the width along the tire width direction of the tire is the maximum The location, height along the rim nominal diameter located in the tire radial direction is increased in the vehicle mounting the side by remote vehicle mounted outside the side, the position where the width along the tire width direction of the tire is maximum up to the tire equatorial plane or rata width along the tire width direction is wider in the vehicle mounted outside than the vehicle inner side.
The pneumatic tire according to claim 2 of the present invention is the pneumatic tire according to claim 1, wherein the elastic modulus of the second reinforcing cord is higher than that of the first reinforcing cord.
A pneumatic tire according to a third aspect of the present invention is the pneumatic tire according to the first or second aspect, wherein the rigidity of the second reinforcing layer in the tire circumferential direction is the tire circumference of the first reinforcing layer. 200-400% of the directional stiffness.
The pneumatic tire according to a fourth aspect of the present invention is the pneumatic tire according to any one of the first to third aspects, wherein the width of the second reinforcing layer on the inner side of the vehicle is set to the width on the outer side of the vehicle. It is wider than the width of the second reinforcing layer.
The pneumatic tire according to a fifth aspect of the present invention is the pneumatic tire according to any one of the first to fourth aspects, wherein the elastic modulus of the second reinforcing cord of the second reinforcing layer inside the vehicle is mounted. However, it is higher than the elastic modulus of the second reinforcement cord of the second reinforcement layer outside the vehicle.
A pneumatic tire according to a sixth aspect of the present invention is the pneumatic tire according to any one of the first to fifth aspects, wherein a resonator is spaced apart in the tire circumferential direction in the second land portion. A plurality of the resonators are formed in an air chamber that is a depression formed in the second land portion, and a tip end portion is connected to a center portion in the tire circumferential direction of the air chamber, and defines the second land portion. And the resonators adjacent to each other in the tire circumferential direction do not overlap each other when viewed from the tire width direction .
The pneumatic tire according to claim 7 of the present invention is the pneumatic tire according to claim 1, wherein the carcass layer is constituted by a plurality of carcass plies, the outer periphery in the tire equatorial plane turnup ends of the carcass ply disposed on the side is located on the inner side in the tire radial direction than the folded end portion of the carcass ply disposed on the inner peripheral side in the tire equatorial plane.

  The pneumatic tire of the present invention improves quietness while ensuring ride comfort.

It is sectional drawing cut | disconnected along the tire axial direction of the pneumatic tire of 1st Embodiment. FIG. 3 is a development view of a tread showing a tread pattern of the tire of FIG. 2. It is the 3X section enlarged view of FIG. It is the 4X section enlarged view of FIG.

(First embodiment)
Hereinafter, a pneumatic tire according to a first embodiment of the present invention will be described.
A pneumatic tire (hereinafter simply referred to as “tire”) 10 according to the first embodiment is a tire mainly used for passenger cars. In addition, this invention is not limited to the pneumatic tire for passenger cars, You may use it for the pneumatic tire of other uses.

FIG. 1 shows a cross-sectional view of the tire 10 cut along the tire axial direction. An arrow W in FIG. 1 indicates a direction parallel to the axis (rotation axis) of the tire 10 (hereinafter referred to as “tire axis direction” as appropriate), and an arrow R is orthogonal to the axis of the tire 10. Direction (hereinafter referred to as “tire radial direction” as appropriate). The tire axial direction may be read as the tire width direction. Reference sign CL indicates the equator plane of the tire 10 (hereinafter referred to as “tire equator plane” as appropriate).
In the present embodiment, the side near the tire equatorial plane CL along the tire axial direction is described as “inner side in the tire axial direction”, and the side far from the tire equatorial plane CL along the tire axial direction is described as “outer side in the tire axial direction”. To do. Further, in the present embodiment, the side near the axis of the tire 10 along the tire radial direction is described as “inner side in the tire radial direction”, and the side far from the axis of the tire 10 along the tire radial direction is described as “outer side in the tire axial direction”. To do.

FIG. 2 is a development view of the tread surface 20A of the tread 20 of the tire 10. An arrow C in FIG. 2 indicates the circumferential direction of the tire 10 (hereinafter referred to as “tire circumferential direction” as appropriate). Moreover, in FIG. 2, only between the grounding ends 20E of the tread surface 20A is illustrated.
“Grounding end” means that the tire 10 is mounted on a standard rim prescribed in JATMA YEAR BOOK (Japan Automobile Tire Association Standard, 2013 edition), and the maximum load capacity (applicable size / ply rating in JATMA YEAR BOOK) It indicates the outer end in the tire axial direction of the ground contact surface when 100% of the internal pressure corresponding to the air pressure (maximum air pressure) corresponding to the internal pressure-load capacity correspondence table is filled and the maximum load capacity is applied. Moreover, in the place of use or manufacturing place of the tire 10, the TRA standard or the ETRTO standard is applied instead of the JATMA standard.

  As shown in FIG. 1, a pneumatic tire 10 according to the first embodiment (hereinafter simply referred to as “tire 10”) has a pair of annular bead portions 12 arranged at intervals in the tire axial direction. An annular bead core 14 embedded in the bead portion 12; a toroidal carcass layer 16 extending from one bead portion 12 to the other bead portion 12 and having both ends locked to the bead cores 14; A belt layer 18 disposed on the outer side in the tire radial direction of the carcass layer 16 forming the tire skeleton, and a tread 20 disposed on the outer side in the tire radial direction from the belt layer 18 and constituting the outermost layer of the tire. ing. In addition, the carcass layer 16, the belt layer 18, and the tread 20 of this embodiment are examples of the carcass layer, the belt layer, and the tread of the present invention, respectively.

The carcass layer 16 is composed of one or a plurality of carcass plies. The carcass ply is formed by rubber coating a plurality of carcass cords (for example, an organic fiber cord or a metal cord). Further, the end of the carcass ply is folded around the bead core 14 from the tire inner side to the tire outer side.
In the present embodiment, as shown in FIGS. 1 and 4, the carcass layer 16 is composed of a carcass ply 16 </ b> A and a carcass ply 16 </ b> B stacked on the outer periphery of the carcass ply 16 </ b> A. Further, the folded end portion 16AE of the carcass ply 16A is located on the outer side in the tire radial direction than the folded end portion 16BE of the carcass ply 16B. Specifically, the turn-up end portion 16AE has a tire section height SH (in other words, a tire cross-section height) along the tire radial direction from the rim nominal diameter position (point P in FIGS. 1 and 4). ) Of 50% or less.
The tire section height SH is a length (height) along the tire radial direction from the rim nominal diameter position P to the radially outermost position of the tire (a position on the tire equatorial plane CL in the present embodiment). is there.

Further, a bead filler 22 is disposed outside the bead core 14 in the tire radial direction so as to be surrounded by the main body portion and the folded portion of the carcass layer 16. The outer end 22A in the tire radial direction of the bead filler 22 has a height H2 along the tire radial direction from the rim nominal diameter position P set within a range of 10 to 30% of the tire section height SH.

The belt layer 18 is composed of a plurality of belt plies. The belt ply is formed by rubber coating a plurality of belt cords (for example, organic fiber cords, metal cords, etc.) extending obliquely with respect to the tire circumferential direction. Further, the plurality of belt cords are arranged so that adjacent ones are parallel to each other.
In this embodiment, as shown in FIGS. 1 and 3, the belt layer 18 is a belt ply 18A and a belt in which the belt ply 18A is overlapped on the outer side in the tire radial direction and is narrower than the belt ply 18A. The ply 18B is composed of a set of two sheets (that is, the belt layer 18 of the present embodiment is a so-called crossing belt layer). Further, the belt cord of the belt ply 18A and the belt cord of the belt ply 18B extend in opposite directions with respect to the tire equatorial plane CL.
In the present embodiment, the belt ply 18A is wider than the belt ply 18B, and both end portions 18AE of the belt ply 18A in the tire axial direction are outside the both ends 18BE of the belt ply 18B in the tire axial direction. Therefore, the end 18AE in the tire axial direction of the belt ply 18A corresponds to the end in the tire axial direction of the belt layer 18 (hereinafter simply referred to as “end of the belt layer 18”). . In this embodiment, the belt ply 18B corresponds to the outermost belt ply of the belt layer 18.

As shown in FIGS. 1 and 3, an endless belt-shaped first reinforcing layer 30 is disposed outside the belt layer 18 in the tire radial direction so as to cover the belt layer 18. Both end portions in the tire axial direction of the first reinforcing layer 30 are located on the outer side in the tire axial direction than both end portions of the belt layer 18, respectively. The first reinforcing layer 30 is composed of one or a plurality of first reinforcing plies. The first reinforcing ply is formed of a rubber-coated first reinforcing cord (for example, an organic fiber cord (preferably a cord formed of polyethylene-2,6-naphthalate, or polyethylene-2, polyparaphenylene terephthalamide). Etc.) are spirally wound in the tire circumferential direction.
In the present embodiment, as shown in FIGS. 1 and 3, the first reinforcing layer 30 is composed of one first reinforcing ply 30 </ b> A. For this reason, in the present embodiment, the end portion 30AE of the first reinforcing ply 30A in the tire axial direction is the end portion of the first reinforcing layer 30 in the tire axial direction (hereinafter simply referred to as “the end portion of the first reinforcing layer 30”). Corresponding to). Therefore, in the present embodiment, both end portions 30AE of the first reinforcing ply 30A are positioned on the outer side in the tire axial direction than both end portions 18AE of the belt ply 18A. In addition, the 1st reinforcement layer 30 of this embodiment is an example of the 1st reinforcement layer of this invention.

The second reinforcing layers 32 are respectively stacked on the outer side in the tire radial direction of the first reinforcing layer 30 and on both end sides. The second reinforcing layer 32 extends in the tire axial direction across the end 18BE of the outermost belt ply 18B. In the present embodiment, the second reinforcing layer 32 straddles the end 18BE of the outermost belt ply 18B and the end 18AE of the innermost belt ply 18A. Further, the end of the second reinforcing layer 32 on the outer side in the tire axial direction is overlapped with the end of the first reinforcing layer 30. The second reinforcing layer 32 is composed of one or a plurality of second reinforcing plies. This second reinforcing ply is made of a rubber-coated second reinforcing cord (for example, an organic fiber cord (preferably a cord made of polyethylene-2,6-naphthalate or polyethylene-2, polyparaphenylene terephthalamide). Etc.) are spirally wound in the tire circumferential direction.
In the present embodiment, as shown in FIGS. 1 and 3, the second reinforcing layer 32 is composed of one second reinforcing ply 32 </ b> A. For this reason, in the present embodiment, the end portion 32AE on the outer side in the tire axial direction of the second reinforcing ply 32A corresponds to the end portion on the outer side in the tire axial direction of the second reinforcing layer 32, and the inner side in the tire axial direction of the second reinforcing ply 32A. The end portion 32AF corresponds to the end portion of the second reinforcing layer 32 on the inner side in the tire axial direction. Therefore, in the present embodiment, the end portion 32AE of the second reinforcement ply 32A overlaps the end portion 30AE of the first reinforcement ply 30A, and the end portion 32AF is located on the inner side in the tire axial direction than the end portion 18BE of the belt ply 18B. In addition, the 2nd reinforcement layer 32 of this embodiment is an example of the 2nd reinforcement layer of this invention.

Further, the second reinforcing layer 32 has higher rigidity in the tire circumferential direction than the first reinforcing layer 30 (hereinafter simply referred to as “circumferential rigidity”). Specifically, the circumferential rigidity of the second reinforcing layer 32 is set in a range of 200 to 400% of the circumferential rigidity of the first reinforcing layer 30.
In the present embodiment, the elastic modulus of the second reinforcing cord of the second reinforcing layer 32 is made higher than the elastic modulus of the first reinforcing cord of the first reinforcing layer 30, and the circumferential rigidity of the second reinforcing layer 32 is the first. The rigidity in the circumferential direction of the reinforcing layer 30 is higher. In addition, this invention is not limited to the said structure, The number of the 2nd reinforcement plies which comprise the 2nd reinforcement layer 32 is increased, and the circumferential direction rigidity of the 2nd reinforcement layer 32 is more than the circumferential direction rigidity of the 1st reinforcement layer 30. The circumferential direction of the second reinforcement layer 32 may be increased by increasing the circumferential rigidity of the second reinforcement ply per sheet by narrowing the driving interval (arrangement interval) of the second reinforcement cords of the second reinforcement ply. The rigidity may be higher than the circumferential rigidity of the first reinforcing layer 30.

  In the present embodiment, the second reinforcing layer 32 on one side in the tire axial direction (left side in FIG. 1) and the second reinforcing layer 32 on the other side in the tire axial direction (right side in FIG. 1) The width (length) W1 along the direction is set to the same width. The present invention is not limited to the above configuration, and the second reinforcing layer 32 on one side in the tire axial direction and the second reinforcing layer 32 on the other side in the tire axial direction have different widths W1 along the tire axial direction. It may be set (details will be described later).

  As shown in FIGS. 1 and 2, circumferential grooves 40 and 42 extending in the tire circumferential direction are formed on both sides of the tire equatorial plane CL on the tread 20 </ b> A of the tread 20, respectively. The circumferential groove 40 is a left circumferential groove in FIG. 2, and the circumferential groove 42 is a right circumferential groove in FIG. Between these circumferential grooves 40 and 42, a rib-shaped land portion 44 continuous in the tire circumferential direction is formed. In the present embodiment, the land portion 44 is formed on the tire equatorial plane CL.

Further, a circumferential groove 46 is formed in the tread 20 on the outer side in the tire axial direction of the circumferential groove 40. Between the circumferential groove 46 and the circumferential groove 40, a rib-like land portion 48 continuous in the tire circumferential direction is formed.
In the tread 20, a circumferential groove 50 is formed on the outer side in the tire axial direction of the circumferential groove 42. Between the circumferential groove 50 and the circumferential groove 42, a rib-like land portion 52 that is continuous in the tire circumferential direction is formed.

  A land portion 54 is formed adjacent to the land portion 48 on the outer side in the tire axial direction of the circumferential groove 46. Further, a land portion 56 is formed adjacent to the land portion 52 on the outer side in the tire axial direction of the circumferential groove 50. In the present embodiment, the land portions 54 and 56 are formed on the respective grounding ends 20E.

  As shown in FIG. 2, a plurality of resonators 60 are formed in the land portion 44 at intervals in the tire circumferential direction (in the present embodiment, constant intervals). The resonator 60 includes an air chamber 60A that is a depression formed in the land portion 44, and a branch groove 60B that branches from the circumferential groove 42 and has a tip portion connected to the air chamber 62A. The branch groove 60B is narrower than the circumferential groove 42. Further, in the present embodiment, the area of the cross section along the direction orthogonal to the groove extending direction of the air chamber 60A is larger than the area of the cross section along the direction orthogonal to the groove extending direction of the branch groove 60B. .

On the circumferential groove 40 side of the land portion 48, a plurality of resonators 62 are formed at intervals in the tire circumferential direction (constant intervals in the present embodiment). The resonator 62 includes an air chamber 62A that is a depression formed in the land portion 48, and a branch groove 62B that branches from the circumferential groove 40 and has a tip portion connected to the air chamber 62A. The branch groove 62 </ b> B is narrower than the circumferential groove 40. Further, in the present embodiment, the area of the cross section along the direction orthogonal to the groove extending direction of the air chamber 62A is larger than the area of the cross section along the direction orthogonal to the groove extending direction of the branch groove 62B. .
On the other hand, a plurality of resonators 64 are formed on the circumferential groove 46 side of the land portion 48 at intervals in the tire circumferential direction (in the present embodiment, constant intervals). The resonator 64 includes an air chamber 64A that is a depression formed in the land portion 48, and a branch groove 64B that branches from the circumferential groove 46 and has a tip portion connected to the air chamber 64A. The branch groove 64 </ b> B is narrower than the circumferential groove 46. In the present embodiment, the area of the cross section along the direction perpendicular to the groove extending direction of the air chamber 64A is larger than the area of the cross section along the direction orthogonal to the groove extending direction of the branch groove 64B. .

A plurality of resonators 66 are formed in the land portion 52 at intervals in the tire circumferential direction (in the present embodiment, a constant interval). The resonator 66 includes an air chamber 66A that is a depression formed in the land portion 52, and a branch groove 66B that branches from the circumferential groove 50 and has a tip portion connected to the air chamber 66A. The branch groove 66 </ b> B is narrower than the circumferential groove 50. Further, in the present embodiment, the area of the cross section along the direction orthogonal to the groove extending direction of the air chamber 66A is larger than the area of the cross section along the direction orthogonal to the groove extending direction of the branch groove 66B. .
Note that the resonators 60, 62, 64, and 66 of this embodiment are examples of the resonator of the present invention.

  The tire 10 of this embodiment is a tire that is mounted so that the land portion 56 is on the inner side in the vehicle width direction. In addition, the arrow IN in FIG. 1 indicates the inner side when the tire 10 is mounted on the vehicle, and the arrow OUT indicates the outer side when the tire 10 is mounted on the vehicle.

As shown in FIG. 1, the tire 10 has a maximum width position height (a height based on the rim nominal diameter position P) excluding a rim protector and side additional protrusions of the tire side portion 13. It is higher at the height position Hout outside the vehicle than the height position Hin.
Further, in the tire 10, the width Wout along the tire axial direction from the tire equator plane CL to the height position Hout on the vehicle mounting outer side is along the tire axial direction from the tire equator plane CL to the height position Hin on the vehicle mounting inner side. It is wider than the width Win. That is, the tire 10 has a cross-sectional shape that is asymmetric with respect to the tire equatorial plane CL. The tire equatorial plane CL is a plane that passes through the center in the tire axial direction between the pair of bead cores 14.

Next, the effect of the tire 10 will be described.
In the tire 10, the first reinforcing layer 30 and the second reinforcing layer 32 restrain the end 18AE of the belt ply 18A and the end 18BE of the belt ply 18B, respectively. For this reason, vibration on the end side (including the end 18AE and the end 18BE) of the running belt layer 18 is suppressed, and road noise is reduced.
Further, in the tire 10, the second reinforcing layers 32 are overlapped on both end sides of the first reinforcing layer 30, and therefore, in the region TC (corresponding to the central portion of the belt layer 18) between the second reinforcing layers 32 on both sides, Since the circumferential rigidity is not excessively high as compared with the region TE in which the two reinforcing layers 32 are disposed, the cavity resonance noise is suppressed. Riding comfort is also ensured.
Furthermore, in the tire 10, since the end portion (end portion 30AE) of the first reinforcing layer 30 and the end portion (end portion 32AE) on the outer side in the tire axial direction of the second reinforcing layer 32 are overlapped, the first reinforcing layer It is possible to suppress vibration and lifting of the end portion of the 30 at the end portion of the second reinforcing layer 32 having higher circumferential rigidity than the first reinforcing layer 30. This further reduces road noise.
From the above, according to the tire 10, quietness can be improved while ensuring ride comfort.

  Further, in the tire 10, since the elastic modulus of the second reinforcing cord of the second reinforcing layer 32 is higher than the elastic modulus of the first reinforcing cord of the first reinforcing layer 30, for example, the number of second reinforcing plies The manufacturing time can be shortened as compared with the case where the number of the first reinforcing plies is increased or the driving distance of the second reinforcing cord is made narrower than the driving distance of the first reinforcing cord.

  In the tire 10, since the circumferential rigidity of the second reinforcing layer 32 is set in a range of 200 to 400% of the circumferential rigidity of the first reinforcing layer 30, the region TE in which the second reinforcing layer 32 is disposed. And the difference in the circumferential rigidity in the region TC between the second reinforcing layers 32 on both sides can be reduced. This suppresses the concentration of stress on the end portion 32AF (the boundary portion between the region TE and the region TC) of the second reinforcing layer 32 while suppressing the vibration of the end portion of the belt layer 18 due to the second reinforcing layer 32. can do.

  Further, in the tire 10, the height H1 of the folded end portion 16AE of the carcass ply 16A is set to 50% or less of the tire section height SH, and the height H2 of the outer end 22A in the tire radial direction of the bead filler 22 is set to the tire section height. Since it is set to 30% or less of SH, the rigidity of the bead portion 12 and the tire side portion 13 is lowered, and the vibration of the end portion of the belt layer 18 is hardly transmitted to the vehicle body. Thereby, the silence of the tire 10 is further improved.

  Further, in the tire 10, air column resonance sounds are generated from the circumferential grooves 40, 42, 46, and 50 during traveling, and these air column resonance sounds are caused by anti-resonance of the resonators 60, 62, 64, and 66, respectively. Reduced. Thereby, the silence of the tire 10 can be further improved.

  Further, in the tire 10, since the height position Hout is higher than the height position Hin and the width Wout is wider than the width Win, the curvature of the curved portion of the tire side portion 13 outside the vehicle is increased. Since the curvature of the curved portion of the tire side portion 13 inside the vehicle is larger than the curvature of the tire side portion 13 outside the vehicle, the rigidity of the tire side portion 13 inside the vehicle is lower. In this way, transmission of vibration to the vehicle body is suppressed by reducing the rigidity of the tire side portion 13 outside the vehicle mounting, and the steering force intended by the driver is increased by increasing the rigidity of the tire side portion 13 inside the vehicle mounting. Transmission to the road surface is facilitated, and the steering stability of the tire 10 is improved.

  In the first embodiment, the width W1 of the second reinforcing layer 32 on both sides is the same, but the present invention is not limited to this configuration, and the width W1 of the second reinforcing layer 32 on both sides may be different. Good. For example, the width of the second reinforcing layer 32 on the vehicle mounting inner side may be wider than the width of the second reinforcing layer 32 on the vehicle mounting outer side. In general tires, the vehicle-mounted inner side is more likely to be vibrated by road surface unevenness than the vehicle-mounted outer side, and vibration at the end of the belt layer tends to increase. Therefore, as described above, if the width of the second reinforcing layer 32 on the vehicle mounting inner side is wider than the width of the second reinforcing layer 32 on the outer side of the vehicle mounting, the vibration of the end of the belt layer 18 on the inner side of the vehicle mounting is vibrated. It can be effectively suppressed. In addition, the width of the second reinforcing layer 32 on the inner side of the vehicle is preferably set within a range of 110 to 150% of the width of the second reinforcing layer 32 on the outer side of the vehicle. By setting the width of the second reinforcing layer 32 on the vehicle mounting inner side within the above numerical range, it is possible to effectively improve the quietness while suppressing a decrease in riding comfort. Furthermore, since the width of the second reinforcing layer 32 on the vehicle mounting inner side is not excessively increased, it is possible to suppress a decrease in rolling resistance due to an increase in tire weight.

  In the first embodiment, the circumferential rigidity of the second reinforcing layers 32 on both sides is the same, but the present invention is not limited to this configuration, and the circumferential rigidity of the second reinforcing layers 32 on both sides is made different. May be. For example, the circumferential rigidity of the second reinforcing layer 32 on the vehicle mounting inner side may be larger than the circumferential rigidity of the second reinforcing layer 32 on the vehicle mounting outer side. Specifically, increasing the number of second reinforcing plies constituting the second reinforcing layer 32 on the vehicle mounting inner side than the number of second reinforcing plies forming the second reinforcing layer 32 on the outer side of the vehicle mounting, The second reinforcement cord driving distance of the second reinforcement ply is made narrower than the second reinforcement cord driving distance of the second reinforcement ply outside the vehicle mounting, and the second reinforcement ply of the second reinforcement ply inside the vehicle mounting By implementing at least one of making the elastic modulus of the cord higher than the elastic modulus of the second reinforcing cord of the second reinforcing ply outside the vehicle mounting, the circumferential rigidity of the second reinforcing layer 32 inside the vehicle mounting can be increased. The rigidity in the circumferential direction of the second reinforcing layer 32 on the vehicle mounting outer side can be made larger. As described above, the circumferential rigidity of the second reinforcing layer 32 on the vehicle mounting inner side is made wider than the circumferential rigidity of the second reinforcing layer 32 on the vehicle mounting outer side, so that the end of the belt layer 18 on the vehicle mounting inner side. Can be effectively suppressed.

In the first embodiment, the end portion (end portion 32AE) of the second reinforcing layer 32 on the outer side in the tire axial direction is overlapped with the end portion (end portion 30AE) of the first reinforcing layer 30, but the present invention has this configuration. However, the end of the second reinforcing layer 32 on the outer side in the tire axial direction may be positioned between the end of the first reinforcing layer 30 and the end of the belt layer 18 (end 18AE).
Here, for example, when the end portion on the outer side in the tire axial direction of the second reinforcing layer 32 is located on the outer side in the tire axial direction with respect to the end portion of the first reinforcing layer 30, the rolling resistance is deteriorated due to an increase in the weight of the tire. If the end portion of the second reinforcing layer 32 on the outer side in the tire axial direction is located between the end portion 18AE of the belt ply 18A and the end portion 18BE of the belt ply 18B, the second reinforcing layer 32 is This greatly contributes to vibration suppression of the end portion 18BE of the ply 18B, but does not greatly contribute to vibration suppression of the end portion 18AE of the belt ply 18A. On the other hand, when the end portion of the second reinforcing layer 32 on the outer side in the tire axial direction is overlapped with the end portion of the first reinforcing layer 30, the rigidity step in the tire axial direction tends to increase at the portion where the end portions overlap each other. There is. Therefore, from the viewpoint of smoothing the rigidity step in the tire axial direction, the end of the second reinforcing layer 32 on the outer side in the tire axial direction is between the end of the first reinforcing layer 30 and the end of the belt layer 18. It is preferable to adopt a configuration to be positioned.

  In the first embodiment, the resonators 60, 62, 64, 66 are formed on the tread 20. However, the present invention is not limited to this configuration, and the resonators 60, 62, 64, 66 on the tread 20. May not be formed. Needless to say, even in this case, it is possible to sufficiently improve quietness while ensuring ride comfort.

  The embodiments of the present invention have been described above with reference to the embodiments. However, these embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. It goes without saying that the scope of rights of the present invention is not limited to these embodiments.

(Test example)
In order to confirm the effect of the present invention, eight types of tires included in the present invention (Examples 1 to 8) and three types of tires not included in the present invention (Comparative Examples 1 to 3) were prepared, and riding comfort And a test to evaluate the quietness. The sizes of the test tires were all 215 / 55R17. The test tire was assembled on a 7Jx17 rim, filled with air so that the internal pressure was 230 kPa, and then mounted on a rear-wheel drive sedan (3000 cc) for testing.

(Evaluation test)
In the test, the speed range (range from low speed to about 100 km / h) experienced by a general driver on a public road on a test course consisting of a peripheral circuit including a long straight part and a handling evaluation road with many gentle curves. ), The driver evaluated the overall quietness and riding comfort in the entire frequency band (250 to 1200 Hz) with a perfect score of 10 points. The evaluation results are shown in Table 1. As for the evaluation result, the larger the value, the better the result.

(Test tire)
The test tire is obtained by improving the tire structure of the tire 10 of the first embodiment. The improved parts are shown in Table 1.

  As can be seen from Table 1, in Examples 1 to 8, compared to Comparative Example 1, a decrease in riding comfort is suppressed, and quietness is improved. On the other hand, it can be seen from the relationship between Comparative Examples 2 and 3 in Table 1 that the difference in circumferential rigidity between the second reinforcing layer and the first reinforcing layer contributes to quietness rather than the resonator. Further, from the relationship between the third embodiment and the eighth embodiment, it is preferable that the second reinforcing layer on the inner side of the vehicle is widened, and the second reinforcing layer on the outer side of the vehicle is widened. The limit value of is known.

  10..Tire (pneumatic tire), 14..Carcass layer, 18..Belt layer, 18B..Outermost belt ply, 30..First reinforcing layer, 30A..First reinforcing ply, 30AE .. End part, 32 ... second reinforcing layer, 32A ... second reinforcing ply, 32AE ... end part, CL ... tire equatorial plane, C ... tire circumferential direction, W ... tire axial direction.

Claims (7)

A plurality of belt plies formed by rubber-covering a plurality of belt cords disposed on the outer side in the tire radial direction of the carcass layer forming the tire skeleton and extending obliquely with respect to the tire circumferential direction Belt layer,
The belt layer is disposed on the outer side in the tire radial direction, and both end portions in the tire axial direction are positioned on the outer side in the tire axial direction with respect to both end portions in the tire axial direction of the belt layer. A first reinforcement layer composed of at least one first reinforcement ply formed by spirally winding in the circumferential direction;
Superimposed respectively on both end sides in the tire axial direction of the first reinforcing layer, straddles the end of the tire axial direction of the belt ply of the outermost layer, or One prior Symbol the belt layer and the end portion of the first reinforcing layer The second reinforcing ply is formed between at least one second reinforcing ply formed by spirally winding a rubber-coated second reinforcing cord in the tire circumferential direction. A second reinforcing layer having higher rigidity in the tire circumferential direction than
A plurality of treads disposed on the outer side in the tire radial direction than the belt layer, and a rib-like land portion continuous in the tire circumferential direction,
The land portion is a first land portion disposed on the tire equator plane, a second land portion disposed adjacent to the vehicle mounting direction outside of the first land portion, and a vehicle mounting direction of the first land portion. A third land portion disposed adjacent to the inside,
The first land portion is formed closer to the vehicle mounting direction inner side than the tire equator plane, and the width of the second land portion is formed larger than the width of the third land portion,
Position width along the tire width direction of the tire is the maximum height along the rim nominal diameter located in the tire radial direction is increased in the vehicle mounting the side by remote vehicle mounted outside the side, the position to the width along the tire width direction of the tire is maximum, the tire equatorial plane or rata width along the tire width direction, than the vehicle inner side is wider in the vehicle mounted outside the pneumatic tire .   The pneumatic tire according to claim 1, wherein the elastic modulus of the second reinforcing cord is higher than that of the first reinforcing cord.   The pneumatic tire according to claim 1 or 2, wherein the rigidity of the second reinforcing layer in the tire circumferential direction is 200 to 400% of the rigidity of the first reinforcing layer in the tire circumferential direction.   The pneumatic tire according to any one of claims 1 to 3, wherein a width of the second reinforcing layer inside the vehicle is wider than a width of the second reinforcing layer outside the vehicle.   5. The elastic modulus of the second reinforcing cord of the second reinforcing layer inside the vehicle mounting is higher than the elastic modulus of the second reinforcing cord of the second reinforcing layer outside the vehicle mounting. The pneumatic tire according to item 1. A plurality of resonators are formed at intervals in the tire circumferential direction in the second land portion ,
The resonator has an air chamber that is a depression formed in the second land portion, and a tip portion is connected to a center portion in the tire circumferential direction of the air chamber and branches from a circumferential groove that defines the second land portion. And a branched groove,
The pneumatic tire according to claim 1 , wherein the resonators adjacent in the tire circumferential direction do not overlap each other when viewed from the tire width direction . The carcass layer is constituted by a plurality of carcass plies, the tire than the folded end portion of the carcass ply turnup ends of the carcass ply disposed on the outer peripheral side in the tire equatorial plane is disposed on the inner peripheral side in the tire equatorial plane The pneumatic tire according to any one of claims 1 to 6, which is located radially inside .

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