JP2018008615A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire which is enabled to achieve stability on a dry road surface, a tire weight and a rolling resistance, at a high level and with a good balance.SOLUTION: In a pneumatic tire of which an installation direction for a vehicle is designated, a bead reinforcement layer is provided on only an outer side of a vehicle, or a periphery length r1 or an elasticity modulus E1 of a bead reinforcement layer 21 on an inner side of the vehicle is differed from a periphery length r2 or an elasticity modulus E1 of a bead reinforcement layer 22 on an outer side of the vehicle so that the periphery lengths r1, r2 or the elasticity moduli E1, E2 satisfy a relation of r1<r2 or E1<E2, and a partial tie rubber layer 10 is selectively located in each of areas on tire width direction both sides which is between a carcass layer 4 and an inner liner layer 9 excluding a center region of a tread part 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire in which a mounting direction with respect to a vehicle is specified. More specifically, the present invention relates to a pneumatic tire that makes it possible to achieve a high balance between steering stability, tire weight, and rolling resistance on a dry road surface. .

  2. Description of the Related Art Recently, in a pneumatic tire in which a mounting direction with respect to a vehicle is specified, the tire structure is different between a vehicle inner side which is an inner side with respect to the vehicle and a vehicle outer side which is outer with respect to the vehicle when mounted on the vehicle. The tire performance is improved (for example, see Patent Document 1). In the tire having an asymmetric structure between the vehicle inner side and the vehicle outer side as described above, the cornering power can be improved as the bending rigidity of the sidewall portion on the vehicle outer side is higher. For example, a plurality of reinforcements are provided in the bead portion. When the bead reinforcement layer including the cord is provided, this bead reinforcement layer is provided only on the bead portion outside the vehicle, or by increasing the peripheral length and elastic modulus of the bead reinforcement layer outside the vehicle, The bending rigidity of the sidewall portion is increased, and the handling stability on the dry road surface can be improved.

  However, the use of a bead reinforcement layer increases the number of tire components and adversely affects the tire weight and rolling resistance.Therefore, there is a limit to improving the steering stability with the bead reinforcement layer as described above. There was a problem that a sufficient effect could not be obtained. Therefore, in order to improve the steering stability by increasing the bending rigidity of the sidewall portion outside the vehicle by the bead reinforcement layer, further improvements for maintaining the tire weight and rolling resistance are required.

Japanese Patent Application Laid-Open No. 2007-083913

  An object of the present invention is to provide a pneumatic tire capable of achieving a high balance between steering stability, tire weight, and rolling resistance on a dry road surface.

  In order to achieve the above object, a pneumatic tire according to a first aspect of the present invention includes a tread portion that extends in the tire circumferential direction and has an annular shape, a pair of sidewall portions that are disposed on both sides of the tread portion, and these side portions. A bead core disposed on the outer periphery of the bead core and a bead core disposed between the pair of bead portions, and a bead filler disposed on an outer periphery of the bead core. A carcass layer folded around the vehicle, a belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, and an inner liner layer disposed on the tire inner surface along the carcass layer, In a pneumatic tire in which the mounting direction with respect to the vehicle is specified, the side that is on the inside of the vehicle when mounted on the vehicle is the inside of the vehicle, and the side that is on the vehicle when mounted on the vehicle is the outside of the vehicle. When the outer side is the vehicle outer side, a bead reinforcing layer including a plurality of reinforcing cords is provided only on the outer bead portion of the pair of bead portions, and the bead reinforcing layer is provided between the carcass layer and the inner liner layer. Thus, a partial tie rubber layer is selectively disposed in each of the regions on both sides in the tire width direction excluding the center region of the tread portion.

  In order to achieve the above object, a pneumatic tire according to a second aspect of the present invention includes a tread portion extending in the circumferential direction of the tire to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, A bead core disposed on the outer periphery of the bead core and a bead core disposed between the pair of bead portions, and a bead filler disposed on an outer periphery of the bead core. A carcass layer folded around the vehicle, a belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, and an inner liner layer disposed on the tire inner surface along the carcass layer, In a pneumatic tire in which the mounting direction with respect to the vehicle is specified, the side that is on the inside of the vehicle when mounted on the vehicle is the inside of the vehicle, and the side that is on the vehicle when mounted on the vehicle is the outside of the vehicle. When the outer side is the vehicle outer side, bead reinforcement layers are respectively provided on the bead portions on the vehicle inner side and the vehicle outer side, and the peripheral length r1 of the bead reinforcement layer on the inner side of the vehicle and the peripheral length r2 of the bead reinforcement layer on the outer side of the vehicle are And the peripheral lengths r1 and r2 satisfy the relationship of r1 <r2, and are between the carcass layer and the inner liner layer and in each region on both sides in the tire width direction excluding the center region of the tread portion. A partial tie rubber layer is selectively disposed.

  In order to achieve the above object, a pneumatic tire according to a third aspect of the present invention includes a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, A bead core disposed on the outer periphery of the bead core and a bead core disposed between the pair of bead portions, and a bead filler disposed on an outer periphery of the bead core. A carcass layer folded around the vehicle, a belt layer disposed on the outer peripheral side of the carcass layer in the tread portion, and an inner liner layer disposed on the tire inner surface along the carcass layer, In a pneumatic tire in which the mounting direction with respect to the vehicle is specified, the side that is on the inside of the vehicle when mounted on the vehicle is the inside of the vehicle, and the side that is on the vehicle when mounted on the vehicle is the outside of the vehicle. Bead reinforcement layers are provided on the bead portions on the vehicle inner side and the vehicle outer side, respectively, and the elastic modulus E1 of the bead reinforcement layer on the vehicle inner side and the elastic modulus E2 of the bead reinforcement layer on the vehicle outer side are different. These elastic moduli E1 and E2 satisfy the relationship of E1 <E2, and are partially tie rubber layers in regions between the carcass layer and the inner liner layer and on both sides in the tire width direction excluding the center region of the tread portion. Is selectively arranged.

  In the pneumatic tire according to the present invention, the bead reinforcement layer is provided only on the vehicle outer side (first invention), and the peripheral length r2 of the bead reinforcement layer on the vehicle outer side is greater than the peripheral length r1 of the bead reinforcement layer on the vehicle inner side. Is larger (second invention) or the elastic modulus E2 of the bead reinforcing layer outside the vehicle is larger than the elastic modulus E1 of the bead reinforcing layer inside the vehicle (third invention). The rigidity of can be increased. As a result, the cornering power at the sidewall portion outside the vehicle can be increased, and the steering stability on the dry road surface can be improved. At this time, the use of a bead reinforcement layer increases the number of tire components, and the use amount of the bead reinforcement layer on the outside of the vehicle increases, so there is a concern about the influence on the tire weight and rolling resistance. As described above, the partial tie rubber layer is used instead of the full tie rubber layer covering the entire width between the carcass layer and the inner liner layer to reduce the tire weight and the rolling resistance. The tire weight and rolling resistance can be maintained well. In the present invention, the “periphery length of the bead reinforcement layer” is a length measured along the extending direction of the bead reinforcement layer in the tire meridian cross section. Further, in the present invention, the “elastic modulus of the bead reinforcing layer” is a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho) in accordance with JIS K6394, temperature 20 ° C., frequency 20 Hz, static strain 10%, dynamic It is a value measured under the condition of strain ± 0.5%.

  In 3rd invention, it is preferable that the elasticity modulus E2 of a bead reinforcement layer is 110 to 300% of the elasticity modulus E1 of a bead reinforcement layer. Thus, by setting the ratio of the elastic modulus E2 to the elastic modulus E1 within an appropriate range, the tire weight and rolling resistance can be well maintained even when the bead reinforcing layer is provided, and the steering stability on the dry road surface It is advantageous to achieve a balance between improving the tire weight and reducing the tire weight and rolling resistance.

  In the second or third aspect of the invention, the peripheral length r2 of the bead reinforcing layer on the vehicle outer side is preferably 105% to 150% of the peripheral length r1 of the bead reinforcing layer on the vehicle inner side. Thus, by setting the ratio of the peripheral length r2 to the peripheral length r1 within an appropriate range, it is possible to maintain good tire weight and rolling resistance even when a bead reinforcing layer is provided, and to control on a dry road surface. It is advantageous to achieve a balance between improving stability and reducing tire weight and rolling resistance.

  In the present invention, the height of the bead reinforcing layer is preferably 5% to 50% of the tire cross-section height SH. Thus, by setting the dimensions of the bead reinforcement layer in an appropriate range, the tire weight and rolling resistance can be maintained well even if the bead reinforcement layer is provided, and the steering stability on the dry road surface is improved and the tire This is advantageous for achieving a balance between weight and reduction of rolling resistance. In the present invention, the “height of the bead reinforcement layer” is a length measured along the tire radial direction from the tire radial inner end of the bead reinforcement layer to the tire radial outer end of the bead reinforcement layer. It is.

  In the present invention, it is preferable that the end portion on the tire equator side of the partial tie rubber layer is disposed in the range of 0 mm to 15 mm from the outermost end portion in the tire width direction of the belt layer toward the inner side in the tire width direction. By setting the position of the end of the tire equator side of the partial tie rubber layer in this way, even a partial tie rubber layer that does not cover the entire width between the carcass layer and the inner liner layer can function as a tie rubber layer (carcass cord Can be reliably and highly exhibited, and it is advantageous for reducing the tire weight and rolling resistance.

  In the present invention, the peripheral length x1 of the partial tie rubber layer inside the vehicle is different from the peripheral length x2 of the partial tie rubber layer outside the vehicle, and the peripheral lengths x1 and x2 satisfy the relationship of x1 <x2. The difference between the lengths x1 and x2 is preferably 5 mm to 30 mm. By increasing the peripheral length of the partial tie rubber layer outside the vehicle in this way, it is possible to increase the rigidity of the sidewall portion outside the vehicle even by the partial tie rubber layer, which is advantageous for improving the handling stability on the dry road surface. Become. At this time, since the difference between the peripheral lengths x1 and x2 is set within an appropriate range, the tire weight and rolling resistance can be maintained well, and the steering stability on the dry road surface is improved and the tire weight and rolling are improved. It is advantageous to achieve a balance between resistance reduction and a good balance. In the present invention, the “periphery length of the partial tie rubber layer” is a length measured along the extending direction of the partial tie rubber layer in the tire meridian cross section.

  At this time, the peripheral length x2 of the partial tie rubber layer outside the vehicle is 30 mm to 120 mm, and the tire radial inner end of the vehicle outer partial tie rubber layer extends from the tire radial outer end of the vehicle bead reinforcement layer to the tire. It is preferable to arrange | position in the range of 10 mm-50 mm on the radial direction outer side. Thus, by setting the peripheral length x2 of the partial tie rubber layer on the outside of the vehicle within an appropriate range and appropriately separating the partial tie rubber layer and the bead filler on the outside of the vehicle, the tire weight and rolling resistance are improved. The steering stability on the dry road surface can be further improved while maintaining.

  In the present invention, the rubber thickness t1 of the partial tie rubber layer inside the vehicle is different from the rubber thickness t2 of the partial tie rubber layer outside the vehicle, and these rubber thicknesses t1 and t2 satisfy the relationship of t1 <t2. The thickness t2 is preferably 120% to 200% of the rubber thickness t1. By increasing the rubber thickness of the partial tie rubber layer on the outside of the vehicle in this way, the partial tie rubber layer can further improve the rigidity of the sidewall portion on the outside of the vehicle, and improve the steering stability on the dry road surface. Will be advantageous. At this time, since the ratio of the rubber thickness t2 to the rubber thickness t1 is set to an appropriate range, the tire weight and rolling resistance can be maintained well, and the steering stability on the dry road surface is improved and the tire This is advantageous for achieving a balance between weight and reduction of rolling resistance. In the present invention, the “rubber thickness” is an average thickness obtained by dividing the cross-sectional area of each partial tie rubber layer by the peripheral length of each partial tie rubber layer in the meridian cross section.

  In the present invention, the partial tie rubber layer preferably has a thickness of 0.1 mm to 1.3 mm. By setting the thickness of the partial tie rubber layer in this manner, the effect of improving the rigidity by the partial tie rubber layer can be sufficiently obtained without adversely affecting the tire weight and rolling resistance.

  In the present invention, the rubber hardness h1 of the partial tie rubber layer inside the vehicle is different from the rubber hardness h2 of the partial tie rubber layer outside the vehicle, the rubber hardness h1 and h2 satisfy the relationship of h1 <h2, and the rubber hardness h2 is rubber. The hardness is preferably 105% to 150% of the hardness h1. In this way, by increasing the rubber hardness of the partial tie rubber layer outside the vehicle, the partial tie rubber layer can further improve the rigidity of the sidewall portion outside the vehicle, and to improve steering stability on the dry road surface Become advantageous. At this time, since the ratio of the rubber hardness h2 to the rubber hardness h1 is set to an appropriate range, the tire weight and rolling resistance can be maintained well, and the steering stability on the dry road surface and the tire weight and This is advantageous for achieving a good balance between reducing rolling resistance. The “rubber hardness” in the present invention is a hardness (so-called JIS-A hardness) measured at a temperature of 20 ° C. by a durometer type A in accordance with JIS K6253.

  In this invention, it is preferable that the hardness of the rubber which comprises a partial tie rubber layer is 50-90. By setting the hardness of the partial tie rubber layer in this manner, the effect of improving the rigidity by the partial tie rubber layer can be sufficiently obtained without adversely affecting the tire weight and rolling resistance.

1 is a meridian cross-sectional view of a pneumatic tire according to a first embodiment of the present invention. It is meridian sectional drawing of the pneumatic tire which consists of 2nd embodiment of this invention. It is meridian sectional drawing of the pneumatic tire which consists of 3rd embodiment of this invention.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIGS. 1 to 3, the pneumatic tire of the present invention includes a tread portion 1 that extends in the tire circumferential direction and has an annular shape, and a pair of sidewall portions 2 that are disposed on both sides of the tread portion 1. And a pair of bead portions 3 disposed inside the sidewall portion 2 in the tire radial direction. In FIG. 1, CL indicates the tire equator. As for this pneumatic tire, the mounting direction with respect to the vehicle is designated. Specifically, the IN side in the figure is the side designated to be inside the vehicle when mounted on the vehicle (hereinafter referred to as the vehicle inside), and the OUT side in the figure is attached to the vehicle when mounted on the vehicle. On the other hand, it is the side designated to be outside (hereinafter referred to as the vehicle outside).

  A carcass layer 4 is mounted between the pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded back around the bead core 5 disposed in each bead portion 3 from the vehicle inner side to the outer side. A bead filler 6 is disposed on the outer periphery of the bead core 5, and the bead filler 6 is wrapped by the main body portion and the folded portion of the carcass layer 4.

  A plurality of layers (two layers in the illustrated example) of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing cords that are inclined with respect to the tire circumferential direction, and is disposed so that the reinforcing cords cross each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in a range of, for example, 10 ° to 40 °. Further, on the outer peripheral side of the belt layer 7, a belt reinforcing layer 8 (a pair of belt reinforcing layers 8 covering both ends of the belt layer 7 in the illustrated example) is provided. The belt reinforcing layer 8 includes an organic fiber cord oriented in the tire circumferential direction. In the belt reinforcing layer 8, the organic fiber cord has an angle with respect to the tire circumferential direction set to, for example, 0 ° to 5 °. An inner liner layer 9 is provided on the inner surface of the tire. The inner liner layer 9 is made of a rubber composition mainly composed of butyl rubber having air permeation preventing performance, and prevents air filled in the tire from permeating out of the tire.

  A bead reinforcement layer 20 is provided on the bead portion 3. In the first embodiment shown in FIG. 1, the bead reinforcement layer 20 is provided only on the bead portion 3 on the vehicle outer side, and no bead reinforcement layer is provided on the bead portion 3 on the vehicle inner side. In the second embodiment shown in FIG. 2, the bead reinforcement layer 20 is provided on each of the bead portions 3 on the vehicle inner side and the vehicle outer side, but the peripheral length r1 of the bead reinforcement layer 21 on the vehicle inner side and the bead reinforcement layer on the vehicle outer side. Unlike the peripheral length r2 of 22, the peripheral lengths r1 and r2 satisfy the relationship r1 <r2. In the third embodiment shown in FIG. 3, the bead reinforcement layer 20 is provided on each of the bead portions 3 on the vehicle inner side and the vehicle outer side as in the second embodiment, but the elastic modulus E1 of the bead reinforcement layer 21 on the vehicle inner side. And the elastic modulus E2 of the bead reinforcement layer 22 on the outside of the vehicle are different, and the elastic moduli E1 and E2 satisfy the relationship E1 <E2. In the example of FIG. 3, the peripheral lengths r1 and r2 of the bead reinforcing layers 21 and 22 are the same. However, in the third embodiment, the peripheral lengths r1 and r2 are r1 <r2. It may be satisfied.

  The bead reinforcing layer 20 is configured by arranging a plurality of reinforcing cords inclined with respect to the tire circumferential direction and burying them in rubber. The inclination angle of the reinforcing cord with respect to the tire circumferential direction may be set to 10 ° to 40 °, for example. As the reinforcing cord, for example, an organic fiber cord made of an organic fiber such as an aramid fiber, a polyethylene fiber, or a nylon fiber, a glass fiber cord, a steel cord, or the like can be used. In the third embodiment described above, for example, the material constituting the reinforcement cord is made different between the bead reinforcement layer 21 on the vehicle inner side and the bead reinforcement layer 22 on the vehicle outer side, or the reinforcement cord is a twisted cord. The elastic modulus E1, E2 can be made different by making the number of twists different between the bead reinforcement layer 21 inside the vehicle and the bead reinforcement layer 22 outside the vehicle.

  In the example of FIGS. 1 to 3, the bead reinforcement layer 20 is disposed on the outer side in the tire width direction of the bead filler 6 and between the bead filler 6 and the carcass layer 4. It is not limited. For example, the rubber layer and the carcass positioned between the carcass layer 4 and the inner liner layer 9, between the bead filler 6 and the carcass layer 4 (inside the bead filler 6 in the tire width direction), and outside the carcass layer 4 in the tire width direction. When two or more carcass layers 4 are provided, it can be disposed between the layers 4 and the carcass layers 4.

  Between the inner liner layer 9 and the carcass layer 4, a partial tie rubber layer 10 (partial tie rubber layer 11 inside the vehicle, partial tie rubber layer 12 outside the vehicle) is disposed. The tie rubber layer disposed between the inner liner layer 9 and the carcass layer 4 prevents the carcass cord from biting into the inner liner layer 9 when inflating an unvulcanized pneumatic tire during tire manufacture. In the tire after manufacture, this layer contributes to air permeation prevention and steering stability on dry road surfaces. Conventionally, it is provided so as to cover the entire area between the carcass layer 4 and the inner liner layer 9. In the present invention, the partial tie rubber layer 10 is selectively provided in a region excluding the center region of the tread portion 1 and the bead portion 3. That is, as shown in FIG. 1, the partial tie rubber layers 10 are respectively provided in the region formed by the shoulder region and the sidewall portion 2 of the tread portion 1 on both sides of the tire equator CL in the tire width direction.

  Thus, when the bead reinforcement layer 20 is provided, the bead reinforcement layer is provided only on the outside of the vehicle (first embodiment), or the peripheral length r2 of the bead reinforcement layer on the outside of the vehicle is set to the periphery of the bead reinforcement layer on the inside of the vehicle. It is made larger than the length r1 (second embodiment), or the elastic modulus E2 of the bead reinforcement layer on the vehicle outer side is made larger than the elastic modulus E1 of the bead reinforcement layer on the vehicle inner side (third embodiment). Thus, the rigidity of the sidewall portion 2 outside the vehicle can be increased. As a result, the cornering power in the sidewall portion 2 outside the vehicle can be increased, and the steering stability on the dry road surface can be improved. At this time, the use of the bead reinforcement layer 20 increases the number of tire components, and the use amount of the bead reinforcement layer 20 on the outside of the vehicle relatively increases, which may affect the tire weight and rolling resistance. However, as the tie rubber layer, a partial tie rubber layer 10 is employed instead of a full tie rubber layer covering the entire width between the carcass layer 4 and the inner liner layer 9 to reduce the tire weight and the rolling resistance. Even with the structure of the bead reinforcing layer 20, the tire weight and rolling resistance can be maintained well.

  At this time, the peripheral lengths r1 and r2 of the bead reinforcement layer 20 in the second embodiment coincide with each other, or the elastic moduli E1 and E2 of the bead reinforcement layer 20 in the third embodiment coincide with each other. If the magnitude relationship is reversed and r1> r2 or E1> E2, the rigidity of the sidewall portion 2 outside the vehicle cannot be increased, and the effect of improving the steering stability on the dry road surface can be obtained. Absent.

  In setting the peripheral lengths r1 and r2 of the bead reinforcing layer 20 to the relationship r1 <r2, the peripheral length r2 is preferably set to 105% to 300%, more preferably 110% to 150% of the peripheral length r1. Good. By setting the ratio of the peripheral length r2 to the peripheral length r1 in this way, the rigidity of the sidewall portion 2 outside the vehicle can be sufficiently and moderately increased without deteriorating the tire weight and rolling resistance. It is advantageous to achieve a good balance between improving steering stability on a dry road surface and reducing tire weight and rolling resistance. At this time, if the peripheral length r2 is smaller than 105% of the peripheral length r1, the rigidity of the sidewall portion 2 outside the vehicle cannot be sufficiently improved, and the effect of improving the steering stability is limited. If the peripheral length r2 is larger than 300% of the peripheral length r1, the use amount of the bead reinforcing layer 20 increases, so that the tire weight and rolling resistance are adversely affected, and it is difficult to sufficiently maintain these performances. Become. In addition, the ride quality and noise vibration may be adversely affected.

  In setting the elastic modulus E1, E2 of the bead reinforcing layer 20 to the relationship of E1 <E2, the elastic modulus E2 is preferably set to 110% to 300%, more preferably 110% to 200% of the elastic modulus E1. Thus, by setting the ratio of the elastic modulus E2 to the elastic modulus E1, the rigidity of the sidewall portion 2 outside the vehicle can be sufficiently and appropriately increased without deteriorating the rolling resistance, and the steering stability on the dry road surface can be improved. It is advantageous to achieve both the improvement of the property and the reduction of the tire weight and rolling resistance in a balanced manner. At this time, if the elastic modulus E2 is smaller than 110% of the elastic modulus E1, the rigidity of the sidewall portion 2 outside the vehicle cannot be sufficiently improved, and the effect of improving the steering stability is limited. If the elastic modulus E2 is larger than 300% of the elastic modulus E1, the rolling resistance is adversely affected, and it becomes difficult to achieve both steering stability and rolling resistance. The elastic moduli E1 and E2 can be set to arbitrary values as long as the above relationship is satisfied. To sufficiently exhibit the above-described effects as a reinforcing layer in a pneumatic tire, for example, the elastic modulus E1 may be set to 7 GPa or more.

  The bead reinforcing layer 20 can be configured in the manner shown in the above-described first to third embodiments, but in any case, the function of the tire is sufficiently exerted and the general performance of the tire is hindered. Therefore, the height RH1 of the bead reinforcement layer 21 inside the vehicle and the height RH2 of the bead reinforcement layer 22 outside the vehicle are preferably 5% to 55%, more preferably 15% to 45% of the tire cross-section height SH. It is good to constitute so that. In particular, when the bead reinforcement layer 20 is provided only on the vehicle outer side as in the first embodiment, the height RH2 of the bead reinforcement layer 22 may be set to 10% to 35% of the tire cross-section height SH. When the height RH1 of the bead reinforcement layer 21 on the vehicle inner side and the height RH2 of the bead reinforcement layer 22 on the vehicle outer side are made different from each other as in the second embodiment, the height RH1 is set to 15 which is the tire cross-section height SH. % To 35% and the height RH2 may be set to 25% to 45% of the tire cross-section height SH. At this time, if the heights RH1 and RH2 of the bead reinforcement layer 20 are both smaller than 5% of the tire cross-section height SH, the effect of providing the bead reinforcement layer 20 cannot be sufficiently obtained. If the height RH1 or RH2 of the bead reinforcing layer 20 is greater than 45% of the tire cross-section height SH, the amount of the bead reinforcing layer 20 used increases, which adversely affects the tire weight and rolling resistance. It becomes difficult to maintain enough.

  The partial tie rubber layer 10 is disposed in a region formed by the shoulder region and the sidewall portion 2 of the tread portion 1 on each of the vehicle inner side and the vehicle outer side, and the carcass cord bites into the inner liner layer 9 during tire manufacture. In order to prevent this, the end portion of the partial tie rubber layer 10 on the tire equator CL side is preferably 0 mm to 15 mm, more preferably from the outermost end portion in the tire width direction of the belt layer 7 toward the inner side in the tire width direction. It is good to arrange | position in the range of 5 mm-10 mm. In other words, the end portion of the partial tie rubber layer 10 on the tire equator CL side is located on the outermost end position in the tire width direction of the belt layer 7 or on the inner side in the tire width direction, and the end portion of the partial tie rubber layer 10 on the tire equator CL side. Distances L1 and L2 in the tire width direction between the end portion and the outermost end portion in the tire width direction of the belt layer 7 are each preferably 0 mm to 15 mm, more preferably 5 mm to 10 mm. By setting the position of the end portion of the partial tie rubber layer 10 on the tire equator CL side as described above, even the partial tie rubber layer 10 that does not cover the entire width between the carcass layer 4 and the inner liner layer 9 can be used as a tie rubber layer. Can be reliably and satisfactorily exhibited, and this is advantageous in reducing tire weight and rolling resistance. At this time, if the end portion of the partial tie rubber layer 10 on the tire equator CL side is located on the outer side in the tire width direction than the outermost end portion in the tire width direction of the belt layer 7, the effect of preventing the carcass cord from getting caught is obtained. It cannot be obtained sufficiently. If the distances L1 and L2 are greater than 15 mm, the amount of the partial tie rubber layer 10 used increases, and the tire weight and rolling resistance are adversely affected, making it difficult to sufficiently maintain these performances.

  Although the structure of the partial tie rubber 11 inside the vehicle and the partial tie rubber layer 12 outside the vehicle may be axisymmetric with respect to the tire equator CL, the peripheral length x1 of the partial tie rubber layer 11 inside the vehicle and the partial tie rubber outside the vehicle. It is preferable that the peripheral length x2 of the layer 12 is different from each other, and the peripheral lengths x1 and x2 satisfy the relationship of x1 <x2. Thus, by increasing the peripheral length x2 of the partial tie rubber layer 12 outside the vehicle, the rigidity of the sidewall portion 2 outside the vehicle can be increased also by the partial tie rubber layer 10, and the steering stability on the dry road surface is improved. Is advantageous. At this time, the difference between the peripheral length x1 and the peripheral length x2 is preferably 5 mm to 30 mm, more preferably 15 mm to 25 mm. Thus, by setting the difference between the peripheral lengths x1 and x2 within an appropriate range, the tire weight and rolling resistance can be well maintained, and the handling stability on the dry road surface is improved and the tire weight and rolling resistance are improved. It is advantageous to achieve both the reduction and balance in a balanced manner. At this time, if the difference between the peripheral lengths x1 and x2 is smaller than 5 mm, the rigidity of the sidewall portion 2 outside the vehicle cannot be sufficiently improved, and the effect of improving the steering stability is limited. If the difference between the peripheral lengths x1 and x2 is larger than 30 mm, the amount of use of the partial tie rubber layer 10 (particularly the partial tie rubber layer 12 outside the vehicle) increases, which adversely affects the tire weight and rolling resistance. It is difficult to maintain sufficient.

  Thus, when the partial tie rubber layer 11 inside the vehicle and the partial tie rubber layer 12 outside the vehicle are made asymmetric, the peripheral length x2 of the partial tie rubber layer 12 outside the vehicle is preferably 30 mm to 120 mm, more preferably 40 mm to 80 mm. It is good to set to. Further, the inner end portion in the tire radial direction of the partial tie rubber layer 12 outside the vehicle is preferably 10 mm to 50 mm, more preferably 25 mm to 35 mm from the outer end portion in the tire radial direction of the bead reinforcement layer 22 outside the vehicle. It is good to arrange in the range. In other words, the tire radial inner end portion of the partial tie rubber layer 12 on the vehicle outer side is disposed on the outer side in the tire radial direction with respect to the tire radial outer end portion of the bead reinforcement layer 22 on the vehicle outer side, and the distance D2 between these end portions. Is preferably set to 10 mm to 50 mm, more preferably 25 mm to 35 mm. In this way, while maintaining a sufficient peripheral length x2 of the partial tie rubber layer 12 on the outside of the vehicle, the partial tie rubber layer 12 and the bead reinforcing layer 22 are appropriately separated from each other, while maintaining good tire weight and rolling resistance. The rigidity of the sidewall portion 2 outside the vehicle can be further increased to further improve the steering stability on the dry road surface. At this time, if the peripheral length x2 is smaller than 30 mm, the partial tie rubber layer 12 itself on the outside of the vehicle becomes small, so that the function as a tie rubber layer (prevention of carcass cord biting) cannot be sufficiently obtained, and the partial tie rubber is also obtained. The rigidity improvement effect by the layer 10 is also limited. If the peripheral length x2 is larger than 120 mm, the amount of the partial tie rubber layer 12 on the outside of the vehicle is increased, which adversely affects the tire weight and rolling resistance, making it difficult to sufficiently maintain these performances. If the distance D2 is smaller than 10 mm, the bead reinforcement layer 22 becomes excessive on the vehicle outer side, and the tire radial inner side end of the partial tie rubber layer 12 on the vehicle outer side and the tire radial outer side of the bead reinforcement layer 22 on the vehicle outer side. Since the end portions interfere with each other, there is a risk of adverse effects on ride comfort and noise vibration. When the distance D2 is greater than 50 mm, the portion of the sidewall portion 2 outside the vehicle that is not reinforced by the partial tie rubber layer 12 or the bead reinforcing layer 22 becomes wide, and it is difficult to sufficiently increase the rigidity of the sidewall portion 2 outside the vehicle. Become.

  The peripheral length x1 of the partial tie rubber layer 11 on the inner side of the vehicle is not particularly limited, but may be set to, for example, 30 mm to 70 mm in order to sufficiently at least exhibit the function as a tie rubber layer (preventing carcass cord biting). Further, when the bead reinforcement layer 21 is also provided on the inner side of the vehicle, the partial tie rubber is also provided on the inner side of the vehicle according to the relationship of the heights RH1 and RH2 of the bead reinforcement layer 20 and the peripheral lengths x1 and x2 of the partial tie rubber layer 10 described above. The inner end portion in the tire radial direction of the layer 11 is disposed on the outer side in the tire radial direction than the outer end portion in the tire radial direction of the bead reinforcement layer 21, but the distance D1 between these end portions is larger than the distance D2. For example, it is preferable that it is 20 mm-80 mm.

  In order to make the partial tie rubber layer 11 inside the vehicle and the partial tie rubber layer 12 outside the vehicle asymmetric so as to increase the rigidity of the sidewall portion 2 outside the vehicle, the peripheral lengths x1 and x2 of the partial tie rubber layer 10 are set as described above. Instead of adjusting, the rubber thickness t1 of the partial tie rubber layer 11 inside the vehicle and the rubber thickness t2 of the partial tie rubber layer 12 outside the vehicle are made different so that these rubber thicknesses t1 and t2 have a relationship of t1 <t2. You may make it satisfy | fill. By increasing the rubber thickness of the partial tie rubber layer on the outside of the vehicle in this way, the partial tie rubber layer can further improve the rigidity of the sidewall portion on the outside of the vehicle, and improve the handling stability on the dry road surface. Will be advantageous. At this time, the rubber thickness t2 is preferably 120% to 200%, more preferably 140% to 180% of the rubber thickness t1. Thus, by setting the ratio of the rubber thickness t2 to the rubber thickness t1 within an appropriate range, the tire weight and rolling resistance can be maintained well, and the handling stability on the dry road surface and the tire weight can be improved. In addition, it is advantageous to achieve a balance between reduction of rolling resistance and balance. At this time, if the rubber thickness t2 is smaller than 120% of the rubber thickness t1, the rigidity of the sidewall portion 2 outside the vehicle cannot be sufficiently improved, and the effect of improving the steering stability is limited. . If the rubber thickness t2 is larger than 200% of the rubber thickness t1, the amount of use of the partial tie rubber layer 10 (particularly the partial tie rubber layer 12 outside the vehicle) increases, which adversely affects the tire weight and rolling resistance. It becomes difficult to maintain these performances sufficiently.

  Even if the thickness t1, t2 of the partial tie rubber layer 10 is different between the inside and the outside of the vehicle as described above, at least the function as a tie rubber layer (carcass cord biting) In order to sufficiently exhibit (prevention of jamming), both are preferably 0.1 mm to 1.3 mm. In particular, when the rubber thickness t1 of the partial tie rubber layer 11 inside the vehicle and the rubber thickness t2 of the partial tie rubber layer 12 outside the vehicle are made different as described above, t1 is set to 0.3 mm to 0.6 mm, t2 Is preferably set to 0.7 mm to 1.0 mm. By setting the thickness of the partial tie rubber layer 10 in this way, the effect of improving the rigidity by the partial tie rubber layer 10 can be sufficiently obtained without adversely affecting the tire weight and rolling resistance. At this time, if the thickness of the partial tie rubber layer 10 is smaller than 0.1 mm, the reinforcing effect by the partial tie rubber layer 10 cannot be sufficiently obtained. If the thickness of the partial tie rubber layer 10 is greater than 1.3 mm, the amount of use of the partial tie rubber layer 10 (particularly the partial tie rubber layer 12 outside the vehicle) increases, which adversely affects the tire weight and rolling resistance. It becomes difficult to maintain sufficient performance.

  When the partial tie rubber layer 11 inside the vehicle and the partial tie rubber layer 12 outside the vehicle are made asymmetric to increase the rigidity of the sidewall portion 2 outside the vehicle, the peripheral lengths x1 and x2 of the partial tie rubber layer 10 are Instead of adjusting the rubber thicknesses t1 and t2, the rubber hardness h1 of the partial tie rubber layer 11 on the vehicle inner side and the rubber hardness h2 of the partial tie rubber layer 12 on the vehicle outer side are made different so that these rubber hardnesses h1 and h2 are h1 <. You may make it satisfy | fill the relationship of h2. In this way, by increasing the rubber hardness of the partial tie rubber layer outside the vehicle, the partial tie rubber layer can further improve the rigidity of the sidewall portion outside the vehicle, and to improve steering stability on the dry road surface Become advantageous. At this time, the rubber hardness h2 is preferably 105% to 150%, more preferably 110% to 130% of the rubber hardness h1. Thus, by setting the ratio of the rubber hardness h2 to the rubber hardness h1 within an appropriate range, the tire weight and rolling resistance can be maintained well, and the handling stability on the dry road surface is improved and the tire weight and rolling are improved. It is advantageous to achieve a balance between resistance reduction and a good balance. At this time, if the rubber hardness h2 is smaller than 105% of the rubber hardness h1, the rigidity of the sidewall portion 2 outside the vehicle cannot be sufficiently improved, and the effect of improving the steering stability is limited. If the rubber hardness h2 is larger than 150% of the rubber hardness h1, the tire weight and rolling resistance are adversely affected, and it is difficult to sufficiently maintain these performances.

  Even if the hardnesses h1 and h2 of the partial tie rubber layer 10 are different between the vehicle inner side and the vehicle outer side as described above, at least the function as a tie rubber layer (carcass cord bite) In order to sufficiently exhibit (prevention), both are preferably 50 to 90. In particular, when the rubber hardness h1 of the partial tie rubber layer 11 inside the vehicle and the rubber hardness h2 of the partial tie rubber layer 12 outside the vehicle are different as described above, h1 is set to 55 to 65, and h2 is set to 70 to 80. It is preferable to do. By setting the hardness of the partial tie rubber layer 10 in this manner, the effect of improving the rigidity by the partial tie rubber layer 10 can be sufficiently obtained without adversely affecting the tire weight and rolling resistance. At this time, if the hardness of the partial tie rubber layer 10 is less than 50, the reinforcing effect by the partial tie rubber layer 10 cannot be sufficiently obtained. If the hardness of the partial tie rubber layer 10 is greater than 90, the tire weight and rolling resistance are adversely affected, and it is difficult to sufficiently maintain these performances.

  As described above, the peripheral length of the partial tie rubber layers 11 and 12 is a structure in which the partial tie rubber layer 11 on the vehicle inner side and the partial tie rubber layer 12 on the vehicle outer side are made asymmetric to increase the rigidity of the sidewall portion 2 on the vehicle outer side. A structure in which x1 and x2 are made different, a structure in which the rubber thicknesses t1 and t2 of the partial tie rubber layers 11 and 12 are made different, and a structure in which the rubber hardness h1 and h2 of the partial tie rubber layers 11 and 12 are made different are shown. These structures can be combined with each other, and by combining them, the rigidity of the sidewall portion 2 outside the vehicle can be further increased, which is advantageous for improving the steering stability on the dry road surface.

  The tire size is 195 / 65r15, and has the basic structure shown in FIGS. 1 to 3, and the arrangement of the bead reinforcing layer, the peripheral length r1 of the bead reinforcing layer inside the vehicle, and the peripheral length r2 of the bead reinforcing layer inside the vehicle (Periphery length r1, r2 magnitude relationship), the peripheral length r1, the peripheral length r2, the ratio of the peripheral length r2 to the peripheral length r1, the elastic modulus E1 of the bead reinforcement layer inside the vehicle and the inside of the vehicle Of the elastic modulus E2 of the bead reinforcement layer (the magnitude relationship of the elastic modulus E1, E2), the elastic modulus E1, the elastic modulus E2, the ratio of the elastic modulus E2 to the elastic modulus E1, and The ratio RH1 / SH of the height RH1, the ratio RH2 / SH of the height RH2 of the bead reinforcement layer to the tire cross-section height SH, the structure of the tie rubber layer, the partial tie inside the vehicle Periphery length x1 of the belt layer, peripheral length x2 of the partial tie rubber layer outside the vehicle, peripheral length difference x2-x1, outermost end in the tire width direction of the belt layer and tire equator side end of the partial tie rubber layer Distances L1 and L2, a distance D2 between the tire radial inner end of the vehicle outer partial tie rubber layer and the tire radial outer end of the vehicle outer bead reinforcement layer, and the rubber thickness t1 of the vehicle inner partial tie rubber layer. The rubber thickness t2 of the partial tie rubber layer outside the vehicle, the rubber hardness h1 of the partial tie rubber layer inside the vehicle, the rubber hardness h2 of the partial tie rubber layer outside the vehicle, and the ratio of the rubber hardness h2 to the rubber hardness h1 h2 / h1 × 100% 42 types of pneumatic tires of Conventional Examples 1 to 4, Comparative Examples 1 to 5, and Examples 1 to 33 were prepared as shown in Tables 1 to 4, respectively.

  In addition, regarding the column of “arrangement of bead reinforcement layer” in Tables 1 to 4, when the bead reinforcement layer is provided only on the bead portion inside the vehicle, “behind”, the bead reinforcement layer is provided only on the bead portion outside the vehicle. “Outer side” when it is applied, and “behind both sides” when the bead reinforcement layer is provided on the bead portion inside the vehicle and outside the vehicle, respectively. In the column of “structure of tie rubber layer”, “full” is described when the tie rubber layer is a full tie rubber layer, and “part” when the tie rubber layer is a partial tie rubber layer. In the conventional examples 1 to 4 in which the tie rubber layer is a full tie rubber layer, since the vehicle inner portion and the vehicle outer portion of the tie rubber layer are continuous, “periphery length x2” and “difference x2−x1” in Table 1 The “distance L1” and “distance L2” columns are blank, and the peripheral length of the entire full tie rubber layer is shown in the “periphery length x1” column for reference.

  About these 42 types of pneumatic tires, the tire weight, rolling resistance, and steering stability on the dry road surface (steering stability) were evaluated by the following evaluation methods, and the results are also shown in Tables 1 to 4.

Tire Weight The weight of each test tire was measured. The evaluation results are shown as an index with the reciprocal of the measured value of Conventional Example 1 being 100. A larger index value means a smaller tire weight. If the index value is “95” or higher, it means that the conventional level is maintained and a sufficiently small tire weight is maintained.

Rolling resistance Each test tire is assembled on a wheel with a rim size of 15 × 6J, and in accordance with ISO28580, using a drum testing machine with a drum diameter of 1707.6 mm, rolling under conditions of air pressure 210 kPa, load 4.82 kN, speed 80 km / h. Resistance was measured. The evaluation results are shown as an index with the reciprocal of the measured value of Conventional Example 1 being 100. It means that rolling resistance is so low that this index value is large. If the index value is “95” or more, it means that the conventional level is maintained and a sufficiently low rolling resistance is maintained.

Steering stability Each test tire was assembled to a wheel with a rim size of 15 × 6J, mounted on a test vehicle with a displacement of 1.5L with an air pressure of 210 kPa, and a sensory evaluation was performed by a test driver on a test course consisting of a dry road surface. . The evaluation results are shown as an index with Conventional Example 1 as 100. The larger the index value, the better the steering stability on the dry road surface.

  As is clear from Tables 1 to 4, Examples 1 to 33 all improved the steering stability while maintaining and reducing the tire weight and rolling resistance with respect to Conventional Example 1. In particular, Example 1 has a structure in which the bead reinforcement layer is provided only on the vehicle outer side as in Conventional Example 1, but the tire weight and rolling resistance are exhibited while exhibiting excellent steering stability as in Conventional Example 1. Improved. On the other hand, in Comparative Example 1, since the bead reinforcement layer is provided only on the inner side of the vehicle, the rigidity of the sidewall portion on the outer side of the vehicle cannot be increased, and the steering stability is deteriorated compared to Conventional Example 1.

  Unlike Conventional Example 1, Conventional Example 2 is provided with bead reinforcement layers on both the inside and outside of the vehicle, and the peripheral length r2 of the bead reinforcement layer on the outside of the vehicle is greater than the peripheral length r1 of the bead reinforcement layer on the inside of the vehicle. Although it is set large, the tire weight and rolling resistance deteriorated because the full tie rubber layer was adopted as the tie rubber layer. As described above, the second embodiment not only maintains and improves the tire weight, rolling resistance, and steering stability as compared with the first conventional example, but also the second conventional example having the same bead reinforcing layer structure. Maintained and improved tire weight, rolling resistance, and handling stability. In Comparative Example 2, since the peripheral length r1 of the bead reinforcement layer on the vehicle inner side is larger than the peripheral length r2 of the bead reinforcement layer on the vehicle outer side, the rigidity of the sidewall portion on the vehicle outer side cannot be increased. Steering stability deteriorated compared to 1 and 2.

  Unlike Conventional Example 1, Conventional Example 3 is provided with bead reinforcement layers on both the vehicle inner side and the vehicle outer side, and the elastic modulus E2 of the vehicle outer bead reinforcing layer is set to be larger than the elastic modulus E1 of the vehicle inner bead reinforcing layer. However, since a full tie rubber layer is used as the tie rubber layer, the tire weight and rolling resistance deteriorated. As described above, the third embodiment not only maintains and improves the tire weight, rolling resistance, and steering stability with respect to the conventional example 1, but also the conventional example 3 having the same bead reinforcing layer structure. Maintained and improved tire weight, rolling resistance, and handling stability. In Comparative Example 3, since the elastic modulus E1 of the bead reinforcement layer on the vehicle inner side is larger than the elastic modulus E2 of the bead reinforcement layer on the vehicle outer side, the rigidity of the sidewall portion on the vehicle outer side cannot be increased. Compared to 3, the steering stability deteriorated.

  Conventional Example 4 is different from Conventional Example 1 in that bead reinforcement layers are provided on both the vehicle inner side and the vehicle outer side, and the peripheral length r2 and elastic modulus E2 of the bead reinforcement layer on the vehicle outer side are the peripherals of the bead reinforcement layer on the vehicle inner side, respectively. Although it is set larger than the length r1 and the elastic modulus E1, the tire weight and rolling resistance are deteriorated because the full tie rubber layer is adopted as the tie rubber layer. Example 4 not only maintains / improves the tire weight, rolling resistance, and steering stability as compared with Conventional Example 1, but also compares the tire weight with respect to Conventional Example 4 having the same bead reinforcing layer structure, Maintained and improved rolling resistance and handling stability. In Comparative Example 4, the peripheral length r1 and the elastic modulus E1 of the bead reinforcing layer inside the vehicle are larger than the peripheral length r2 and the elastic modulus E2 of the bead reinforcing layer outside the vehicle, respectively. As a result, the steering stability deteriorated compared to the conventional examples 1 and 4. In Comparative Example 5, since the peripheral length and the elastic modulus of the bead reinforcement layer on the vehicle inner side and the vehicle outer side are equal (r1 = r2 and E1 = E2), the rigidity of the sidewall portion on the vehicle outer side cannot be increased. Steering stability deteriorated compared to Examples 1 and 4.

  In Examples 5 to 8, the height of the belt reinforcing layer is changed in the same structure as that in Example 1 (structure in which the bead reinforcing layer is provided only on the vehicle outer side). The tire weight, rolling resistance, and steering stability were maintained and improved. In particular, Examples 6 to 7 in which the ratio of the height RH2 of the belt reinforcing layer to the tire cross-section height SH was set within a preferable range achieved both of these performances in a well-balanced manner. Examples 9 to 12 have the same structure as that of Example 2 (a structure in which bead reinforcement layers are provided on both the vehicle inner side and the vehicle outer side and the peripheral lengths r1 and r2 satisfy the relationship of r1 <r2). In each example, the tire weight, rolling resistance, and steering stability were maintained and improved with respect to Conventional Example 2 in addition to Conventional Example 1. In particular, Examples 10 to 11 in which the ratio of the peripheral length r2 to the peripheral length r1 was set in a preferable range achieved a good balance between these performances. Examples 13 to 16 have the same structure as that of Example 3 (a structure in which bead reinforcement layers are provided on both the vehicle inner side and the vehicle outer side and the elastic moduli E1 and E2 satisfy the relationship of E1 <E2). Although the elastic modulus of the belt reinforcing layer was changed, each example maintained and improved the tire weight, rolling resistance, and steering stability with respect to Conventional Example 3 in addition to Conventional Example 1. In particular, Examples 14 to 15 in which the ratio of the elastic modulus E2 to the elastic modulus E1 was set in a preferable range achieved both of these performances in a well-balanced manner.

  In Examples 17 to 33, a partial tie rubber is used in the same structure as Example 2 (a structure in which bead reinforcement layers are provided on both the vehicle inner side and the vehicle outer side and the peripheral lengths r1 and r2 satisfy the relationship of r1 <r2). Although the layer structure was changed, each example maintained and improved the tire weight, rolling resistance, and steering stability compared to Conventional Example 1 in addition to Conventional Example 1. In particular, the example in which each parameter is set within a suitable range achieves a balance between these performances. Although not shown in the table, Example 1 (a structure in which the bead reinforcement layer is provided only on the outside of the vehicle), Example 3 (the bead reinforcement layer is provided on both the inside of the vehicle and the outside of the vehicle, and the elastic modulus E1). , E2 satisfying the relationship of E1 <E2), Example 4 (bead reinforcement layers are provided both inside and outside the vehicle, the peripheral lengths r1, r2 and the elastic modulus E1, E2 are r1 <r2 and E1) <Structure satisfying the relationship of E2> In the same structure as each of the first to third embodiments, when each parameter is changed in the same manner as in the seventeenth to thirty-third examples, The same results as in Examples 17 to 33 with respect to Example 2 were obtained.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Belt reinforcement layer 9 Inner liner layer 10 Partial tie rubber layer 11 Partial tie rubber layer inside a vehicle 12 Partial tie rubber layer 20 outside a vehicle reinforcement Layer 21 Bead reinforcement layer inside the vehicle 22 Bead reinforcement layer outside the vehicle CL Tire equator IN Vehicle inside OUT Vehicle outside

Claims (13)

An annular tread portion extending in the tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the sidewall portions. A carcass layer folded between a bead core provided between the pair of bead portions and provided on each bead portion and a bead filler disposed on an outer periphery of the bead core, and the carcass in the tread portion. In a pneumatic tire having a belt layer arranged on the outer peripheral side of the layer and an inner liner layer arranged on the tire inner surface along the carcass layer, and a mounting direction with respect to the vehicle is designated,
When the vehicle inner side is defined as the vehicle inner side when mounted on the vehicle, and the vehicle outer side is defined as the vehicle outer side when mounted on the vehicle, the outer side of the pair of bead portions A bead reinforcement layer including a plurality of reinforcement cords is provided only in the bead portion, and is provided between each of the regions on the both sides in the tire width direction except for the center region of the tread portion between the carcass layer and the inner liner layer. A pneumatic tire, wherein a tie rubber layer is selectively disposed. An annular tread portion extending in the tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the sidewall portions. A carcass layer folded between a bead core provided between the pair of bead portions and provided on each bead portion and a bead filler disposed on an outer periphery of the bead core, and the carcass in the tread portion. In a pneumatic tire having a belt layer arranged on the outer peripheral side of the layer and an inner liner layer arranged on the tire inner surface along the carcass layer, and a mounting direction with respect to the vehicle is designated,
When the vehicle is mounted on the vehicle, the inner side is the vehicle inner side, and when the vehicle is mounted on the vehicle, the outer side is the vehicle outer side. A bead reinforcing layer is provided, and the peripheral length r1 of the bead reinforcing layer inside the vehicle is different from the peripheral length r2 of the bead reinforcing layer outside the vehicle, and the peripheral lengths r1 and r2 satisfy the relationship r1 <r2. A pneumatic tire characterized in that a partial tie rubber layer is selectively disposed in each region on both sides in the tire width direction excluding the center region of the tread portion between the carcass layer and the inner liner layer. An annular tread portion extending in the tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the sidewall portions. A carcass layer folded between a bead core provided between the pair of bead portions and provided on each bead portion and a bead filler disposed on an outer periphery of the bead core, and the carcass in the tread portion. In a pneumatic tire having a belt layer arranged on the outer peripheral side of the layer and an inner liner layer arranged on the tire inner surface along the carcass layer, and a mounting direction with respect to the vehicle is designated,
When the vehicle is mounted on the vehicle, the inner side is the vehicle inner side, and when the vehicle is mounted on the vehicle, the outer side is the vehicle outer side. A bead reinforcing layer is provided, the elastic modulus E1 of the bead reinforcing layer inside the vehicle is different from the elastic modulus E2 of the bead reinforcing layer outside the vehicle, and these elastic moduli E1 and E2 satisfy the relationship of E1 <E2, and the carcass layer A partial tie rubber layer is selectively disposed in each region on both sides of the tire width direction excluding the center region of the tread portion between the inner liner layer and the inner liner layer.   The pneumatic tire according to claim 3, wherein an elastic modulus E2 of the bead reinforcing layer outside the vehicle is 110% to 300% of an elastic modulus E1 of the bead reinforcing layer inside the vehicle.   The pneumatic tire according to any one of claims 2 to 4, wherein the peripheral length r2 of the bead reinforcing layer outside the vehicle is 105% to 300% of the peripheral length r1 of the bead reinforcing layer inside the vehicle. .   The pneumatic tire according to any one of claims 1 to 5, wherein a height of the bead reinforcing layer is 5% to 50% of a tire cross-section height SH.   The tire equator-side end portion of the partial tie rubber layer is disposed in a range of 0 mm to 15 mm from the outermost end portion of the belt layer in the tire width direction toward the inner side in the tire width direction. The pneumatic tire according to any one of 6.   The peripheral length x1 of the partial tie rubber layer on the inner side of the vehicle is different from the peripheral length x2 of the partial tie rubber layer on the outer side of the vehicle. The peripheral lengths x1 and x2 satisfy the relationship x1 <x2, and the peripheral lengths x1 and x2 The pneumatic tire according to claim 1, wherein the difference is 5 mm to 30 mm.   The peripheral length x2 of the partial tie rubber layer outside the vehicle is 30 mm to 120 mm, and the tire radial inner end of the vehicle outer partial tie rubber layer extends from the tire radial outer end of the bead reinforcement layer outside the vehicle. The pneumatic tire according to claim 8, wherein the pneumatic tire is arranged in a range of 10 mm to 50 mm on a radially outer side.   The rubber thickness t1 of the partial tie rubber layer inside the vehicle is different from the rubber thickness t2 of the partial tie rubber layer outside the vehicle, the rubber thicknesses t1 and t2 satisfy the relationship of t1 <t2, and the rubber thickness t2 is The pneumatic tire according to any one of claims 1 to 5, wherein the tire has a rubber thickness t1 of 120% to 200%.   The pneumatic tire according to claim 1, wherein the partial tie rubber layer has a thickness of 0.1 mm to 1.3 mm.   The rubber hardness h1 of the partial tie rubber layer inside the vehicle is different from the rubber hardness h2 of the partial tie rubber layer outside the vehicle. The rubber hardness h1 and h2 satisfy the relationship of h1 <h2, and the rubber hardness h2 is 105% of the rubber hardness h1. The pneumatic tire according to any one of claims 1 to 11, wherein the pneumatic tire is -150%.   The pneumatic tire according to any one of claims 1 to 12, wherein the hardness of the rubber constituting the partial tie rubber layer is 50 to 90.

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