JP2018008619A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire comprising a partial rubber layer selectively located on a part of an interlayer between a carcass layer and an inner liner layer, maintaining braking performance on a dry road surface, and enabled to be reduced in tire weight and rolling resistance.SOLUTION: In a pneumatic tire, an inner tie rubber layer 11 and an outer tie rubber layer 12 are respectively selectively located in areas on tire width direction both sides each of which is between a carcass layer 4 and an inner liner layer 9 excluding a center region of a tread part 1, ends of the inner tie rubber layer 11 and the outer tie rubber layer 12 on a tire equator side are respectively located within a range of 0 mm to 15 mm from an end of a belt layer 7 on a tire width direction outermost side to a tire width direction inner side, a rubber thickness of the inner tie rubber layer 11 is differed from a rubber thickness of the outer tie rubber layer 12, and a rubber thickness t1 of the inner tie rubber layer 11 is made to be 120% to 200% of a rubber thickness t2 of the outer tie rubber layer 12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire including a partial tie rubber layer that is selectively disposed in a portion between a carcass layer and an inner liner layer, and more specifically, while maintaining braking performance on a dry road surface, the tire weight The present invention also relates to a pneumatic tire that can reduce rolling resistance.

  In pneumatic tires, tie rubber is generally provided between the carcass layer and the inner liner layer in order to prevent the carcass cord from biting into the inner liner layer when the unvulcanized tire is inflated during tire manufacture. Layers are placed. In recent years, in order to reduce the tire weight and rolling resistance, such a tie rubber layer has adopted a partial tie rubber layer that is selectively disposed on a part rather than the entire area between the carcass layer and the inner liner layer. Has been proposed (see, for example, Patent Document 1). Such a partial tie rubber layer is disposed at least in the shoulder region (a portion where the carcass cord is easily entrapped at the time of inflation due to a large curvature), thereby being disposed in the entire region between the carcass layer and the inner liner layer. A sufficient effect can be obtained as compared with a conventional tie rubber layer (full tie rubber layer).

  However, simply removing a part of the full tie rubber layer to make it a partial tie rubber layer results in lower rigidity than conventional tires that use the full tie rubber layer, so braking performance on dry road surfaces, especially when set to negative camber There is a problem that it is difficult to sufficiently maintain (dry braking performance). For this reason, when the tire weight and rolling resistance are reduced by the partial tie rubber layer, further improvement for preventing a decrease in dry braking performance is demanded.

Japanese Patent No. 5239507

  An object of the present invention is a pneumatic tire including a partial tie rubber layer that is selectively disposed in a part between the carcass layer and the inner liner layer, and maintains the braking performance on the dry road surface while maintaining the tire weight. It is another object of the present invention to provide a pneumatic tire that can reduce rolling resistance.

  In order to achieve the above object, a pneumatic tire according to a first aspect of the present invention includes a tread portion that is specified in a mounting direction with respect to a vehicle and that extends in the tire circumferential direction to form an annular shape, and a pair disposed on both sides of the tread portion. And a pair of bead portions disposed inside the tire radial direction of the sidewall portions, a carcass layer is mounted between the pair of bead portions, and an outer periphery of the carcass layer in the tread portion A belt layer is disposed on the side, an inner liner layer is disposed on the inner surface of the tire along the carcass layer, and both sides of the tire width direction excluding the center region of the tread portion between the carcass layer and the inner liner layer In the pneumatic tire in which the partial tie rubber layer is selectively disposed in each of the regions, the end of each partial tie rubber layer on the tire equator side is the bell. The inner tie rubber layer disposed on the vehicle inner side of the partial tie rubber layer and the outer side of the partial tie rubber layer on the vehicle outer side. The outer tie rubber layer is different in rubber thickness, and the rubber thickness t1 of the inner tie rubber layer is 120% to 200% of the rubber thickness t2 of the outer tie rubber layer.

  In order to achieve the above object, a pneumatic tire according to a second aspect of the present invention is directed to a pair of tires that are specified in a mounting direction with respect to a vehicle and that extend in the tire circumferential direction to form an annular shape, and are disposed on both sides of the tread portion. And a pair of bead portions disposed inside the tire radial direction of the sidewall portions, a carcass layer is mounted between the pair of bead portions, and an outer periphery of the carcass layer in the tread portion A belt layer is disposed on the side, an inner liner layer is disposed on the inner surface of the tire along the carcass layer, and both sides of the tire width direction excluding the center region of the tread portion between the carcass layer and the inner liner layer In the pneumatic tire in which the partial tie rubber layer is selectively disposed in each of the regions, the end of each partial tie rubber layer on the tire equator side is the bell. The inner tie rubber layer disposed on the vehicle inner side of the partial tie rubber layer and the outer side of the partial tie rubber layer on the vehicle outer side. The peripheral length differs depending on the outer tie rubber layer to be disposed, and the difference Δx between the peripheral length x1 of the inner tie rubber layer and the peripheral length x2 of the outer tie rubber layer is 5 to 30 mm.

  In order to achieve the above object, a pneumatic tire according to a third aspect of the present invention is directed to a pair of tires that are specified in the vehicle mounting direction and that extend in the tire circumferential direction to form an annular shape, and are arranged on both sides of the tread portion. And a pair of bead portions disposed inside the tire radial direction of the sidewall portions, a carcass layer is mounted between the pair of bead portions, and an outer periphery of the carcass layer in the tread portion A belt layer is disposed on the side, an inner liner layer is disposed on the inner surface of the tire along the carcass layer, and both sides of the tire width direction excluding the center region of the tread portion between the carcass layer and the inner liner layer In the pneumatic tire in which the partial tie rubber layer is selectively disposed in each of the regions, the end of each partial tie rubber layer on the tire equator side is the bell. The inner tie rubber layer disposed on the vehicle inner side of the partial tie rubber layer and the outer side of the partial tie rubber layer on the vehicle outer side. The outer tie rubber layer is different in rubber hardness, and the rubber hardness h1 of the inner tie rubber layer is 105% to 150% of the rubber hardness h2 of the outer tie rubber layer.

  In the present invention, since the partial tie rubber layer is employed, the tire weight and rolling resistance can be reduced as compared with a conventional pneumatic tire having a full tie rubber layer. At this time, the rubber thickness (first invention), the peripheral length (second invention), or the rubber hardness (first invention) is determined by the inner tie rubber layer arranged inside the vehicle and the outer tie rubber layer arranged outside the vehicle. By making the third invention) different and making them larger at the inner tie rubber layer than at the outer tie rubber layer, the rigidity of the sidewall portion inside the vehicle can be increased, and the dry braking performance can be maintained at a high level. .

  The first invention, the second invention, and the third invention can be combined with each other. That is, in the first invention (when the rubber thickness is set), the peripheral length differs between the inner tie rubber layer and the outer tie rubber layer, and the peripheral length x1 of the inner tie rubber layer and the peripheral length x2 of the outer tie rubber layer The difference Δx is preferably 5 mm to 30 mm. As a result, the rigidity of the sidewall portion inside the vehicle can be further increased, which is advantageous for improving the dry handling stability.

  In the first invention (when the rubber thickness is set) or the second invention (when the peripheral length is set), the inner tie rubber layer and the outer tie rubber layer have different rubber hardness, and the rubber of the inner tie rubber layer The hardness h1 is preferably 105% to 150% of the rubber hardness h2 of the outer tie rubber layer. As a result, the rigidity of the sidewall portion inside the vehicle can be further increased, which is advantageous for improving the dry handling stability.

  In the present invention, the “rubber thickness” is an average thickness obtained by dividing the cross-sectional area of the inner tie rubber layer or the outer tie rubber layer in the meridian section by the respective peripheral lengths. The “periphery length” is a length measured along the extending direction of each tire component (outer tie rubber layer, inner tie rubber layer) in the tire meridian cross section. “Rubber hardness” is hardness (so-called JIS-A hardness) measured at a temperature of 23 ° C. with a durometer type A in accordance with JIS K6253.

1 is a meridian cross-sectional view of a pneumatic tire according to an embodiment of the present invention. It is meridian sectional drawing of the pneumatic tire which consists of another embodiment of this invention. It is meridian sectional drawing of the pneumatic tire which consists of another embodiment of this invention. It is meridian sectional drawing of the pneumatic tire which consists of another 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 FIGS. 1 to 3, CL represents 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. On the other hand, a plurality of layers (two layers in the example of FIGS. 1 to 3) 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, a belt reinforcement layer 8 (a pair of belt reinforcement layers 8 covering both ends of the belt layer 7 in the example of FIGS. 1 to 3) is provided on the outer peripheral side of the belt layer 7. 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 partial tie rubber layer 10 is disposed between the carcass layer 4 and the inner liner layer 9. The partial tie rubber layer 10 is a layer for preventing the carcass cord from biting into the inner liner layer 9 when inflating an unvulcanized pneumatic tire at the time of manufacturing the tire, but like a conventional tie rubber layer. It does not cover the entire region between the carcass layer 4 and the inner liner layer 9 but 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 FIGS. 1 to 3, the partial tie rubber layers 10 are respectively provided in regions on both sides in the tire width direction of the tire equator CL composed of the shoulder region of the tread portion 1 and the sidewall portion 2. Specifically, the end of each partial tie rubber layer 10 on the tire equator CL side is in the range of 0 mm to 15 mm, preferably 5 mm to 10 mm inward in the tire width direction from the outermost end of the belt layer 7 in the tire width direction. Is arranged. In other words, the end of each partial tie rubber layer 10 on the tire equator CL side is located at the outermost end position in the tire width direction of the belt layer 7 or the inner side in the tire width direction, and the tire equator CL of the partial tie rubber layer 10. The distances L1 and L2 in the tire width direction between the end portion on the side and the outermost end portion in the tire width direction of the belt layer 7 are set to 0 mm to 15 mm, preferably 5 mm to 10 mm, respectively. On the other hand, the end portion of each partial tie rubber layer 10 on the bead portion 3 side is disposed closer to the tread portion 1 than the bead core 5.

  As described above, since the partial tie rubber layer 10 is selectively provided in a specific region, the conventional tie rubber covering the entire region between the carcass layer 4 and the inner liner layer 9 while maintaining the function as the tie rubber layer. Compared to a pneumatic tire having a layer (full tie rubber layer), the tire weight can be reduced and the rolling resistance can be reduced. At this time, if the end portion of the partial tie rubber layer 10 on the tire equator CL side is disposed on the tire equator CL side than the above range, the amount of the partial tie rubber layer 10 increases, so that the tire weight and rolling resistance are sufficiently increased. It cannot be reduced. When the end portion of the partial tie rubber layer 10 on the tire equator CL side is disposed on the outer side in the tire width direction from the above range, the carcass cord can be sufficiently prevented from biting into the inner liner layer 9 during inflation. Can not.

  At this time, in the present invention, among the pair of partial tie rubber layers 10, the inner tie rubber layer 11 disposed on the vehicle inner side and the outer tie rubber layer 12 disposed on the vehicle outer side have different structures (dimensions) and physical properties. The dry braking performance is improved by increasing the rigidity of the side wall 2 on the inside of the vehicle, which increases the ground contact area when mounted on a general vehicle that is mainly set to a negative camber (camber angle is 0 ° to −15 °). It is prevented from lowering than a conventional pneumatic tire having a full tie rubber layer. That is, an excellent dry braking performance equal to or better than that of a conventional pneumatic tire having a full tie rubber layer is obtained.

  First, in the embodiment of FIG. 1, the rubber thicknesses of the inner tie rubber layer 11 and the outer tie rubber layer 12 are different. Specifically, the rubber thickness t1 of the inner tie rubber layer 11 is made larger than the rubber thickness t2 of the outer tie rubber layer 12, and the rubber thickness t1 of the inner tie rubber layer 11 is 120, which is the rubber thickness t2 of the outer tie rubber layer 12. % To 200%, preferably 130% to 170%. At this time, if the rubber thickness t1 is smaller than 120% of the rubber thickness t2, the inner tie rubber layer 11 is not sufficiently thick, and the side wall portion inside the vehicle cannot be properly reinforced to increase the rigidity. The dry braking performance cannot be improved. When the rubber thickness t1 is larger than 200% of the rubber thickness t2, the tire weight reduction effect is reduced. Further, when the tire constituent members are laminated at the time of manufacturing the tire, there is a large step between the portion where the tie rubber layer is present and the portion where the tie rubber layer is not present, and it becomes difficult to form a suitable tire shape.

  Even if the rubber thicknesses t1 and t2 of the inner tie rubber layer 11 and the outer tie rubber layer 12 satisfy the above relationship, if each tie rubber layer is extremely thin, the reinforcing effect by the tie rubber layer cannot be sufficiently expected. Since the reduction effect cannot be sufficiently expected, the rubber thickness t1 of the inner tie rubber layer 11 may be set to 0.7 mm to 1.0 mm, for example, and the rubber thickness t2 of the outer tie rubber layer 12 may be set to 0.5 mm to 0.8 mm, for example.

  Next, in the embodiment of FIG. 2, the peripheral lengths of the inner tie rubber layer 11 and the outer tie rubber layer 12 are different. Specifically, the peripheral length x1 of the inner tie rubber layer 11 is made larger than the peripheral length x2 of the outer tie rubber layer 12, and the difference Δx (= x1-x2) between the peripheral length x1 and the peripheral length x2 is set. It is set to 5 mm to 30 mm. At this time, if the difference Δx is smaller than 5 mm, the inner tie rubber layer 11 is not sufficiently long, the side wall portion 2 inside the vehicle cannot be properly reinforced and the rigidity cannot be increased, and the dry braking performance is improved. Can not do it. If the difference Δx is greater than 30 mm, the effect of reducing the tire weight decreases. Further, the inner tie rubber layer 11 extends to the vicinity of the bead portion 3, and the rigidity of the sidewall portion 2 on the vehicle inner side increases to the vicinity of the bead portion 3, so that the fitting property with respect to the rim decreases (the vehicle inner side and There is a difference in fitability to the rim between the outside of the vehicle).

  Even if the peripheral lengths x1 and x2 of the inner tie rubber layer 11 and the outer tie rubber layer 12 satisfy the above relationship, if each tie rubber layer is extremely short, the reinforcing effect by the tie rubber layer cannot be sufficiently expected. Since the reduction effect cannot be sufficiently expected, the peripheral length x1 of the inner tie rubber layer 11 may be set to 50 mm to 80 mm, for example, and the peripheral length x2 of the outer tie rubber layer 12 may be set to 40 mm to 70 mm, for example.

  Further, in the embodiment of FIG. 3, the inner tie rubber layer 11 and the outer tie rubber layer 12 have different rubber hardness. Specifically, the rubber hardness h1 of the inner tie rubber layer 11 is made larger than the rubber hardness h2 of the outer tie rubber layer 12, and the rubber hardness h1 of the inner tie rubber layer 11 is 105% to 150% of the rubber hardness h2 of the outer tie rubber layer 12. It is set to. At this time, if the rubber hardness h1 is smaller than 105% of the rubber hardness h2, the inner tie rubber layer 11 is not sufficiently hard, and the side wall portion 2 inside the vehicle cannot be properly reinforced to increase the rigidity. The dry braking performance cannot be improved. When the rubber hardness h1 is larger than 150% of the rubber hardness h2, the influence on the rolling resistance becomes large, and a sufficient reduction of the rolling resistance cannot be expected. Moreover, workability and cost deteriorate.

  Even if the rubber hardness h1 and h2 of the inner tie rubber layer 11 and the outer tie rubber layer 12 satisfy the above relationship, if the tie rubber layers are extremely low in hardness, the reinforcing effect by the tie rubber layers cannot be expected sufficiently, and the hardness is extremely high. If there is, a sufficient reduction in rolling resistance cannot be expected. Therefore, the rubber hardness h1 of the inner tie rubber layer 11 may be set to 70 to 90, for example, and the rubber hardness h2 of the outer tie rubber layer 12 may be set to 55 to 65, for example.

  In the embodiment of FIGS. 1 to 3, the inner tie rubber layer 11 and the outer tie rubber layer 12 are different in any one of rubber thickness (FIG. 1), peripheral length (FIG. 2), and rubber hardness (FIG. 3). However, two or more of these parameters may be made different at the same time. Thus, by making two or more parameters different simultaneously, the reinforcement effect of the side wall part 2 inside a vehicle can be heightened, and dry steering stability can be improved effectively.

  For example, as shown in FIG. 4, the inner tie rubber layer 11 and the outer tie rubber layer 12 can have different rubber thicknesses and peripheral lengths. In this case, the rubber thickness t1 and the peripheral length x2 of the inner tie rubber layer 11 are larger than the rubber thickness t2 and the peripheral length x2 of the outer tie rubber layer 12, respectively, and the rubber thickness t1, t2 and the peripheral length x1, x2 Satisfy the above-mentioned relationship. Further, in the structure of FIGS. 1, 2, and 4, the rubber hardness h1 and h2 of the inner tie rubber layer 11 and the outer tie rubber layer 12 can be set so as to satisfy the above relationship.

  When two or more parameters are combined in this way, the influence of each parameter on the tire weight, rolling resistance, or dry steering stability performance is different, and the influence on the original tire performance due to the synergistic effect is considered. Thus, it is preferable to set the range of each parameter. That is, when combining the rubber thickness and the peripheral length, the rubber thickness t1 of the inner tie rubber layer 11 is set to 140% to 160% of the rubber thickness t2 of the outer tie rubber layer 12, and the peripheral length x1 of the inner tie rubber layer 11 is set. The difference Δx between the outer tie rubber layer 12 and the peripheral length x2 of the outer tie rubber layer 12 is preferably set to 10 mm to 100 mm.

  Alternatively, when the rubber thickness and the rubber hardness are combined, the rubber thickness t1 of the inner tie rubber layer 11 is set to 140% to 160% of the rubber thickness t2 of the outer tie rubber layer 12, and the rubber hardness h1 of the inner tie rubber layer 11 is set. It is preferable to set it to 105% to 150% of the rubber hardness h2 of the outer tie rubber layer 12.

  Alternatively, when combining the peripheral length and rubber hardness, the difference Δx between the peripheral length x1 of the inner tie rubber layer 11 and the peripheral length x2 of the outer tie rubber layer 12 is set to 10 mm to 100 mm, and the rubber hardness of the inner tie rubber layer 11 is set. h1 is preferably set to 105% to 150% of the rubber hardness h2 of the outer tie rubber layer 12.

  Alternatively, when all of the rubber thickness, the peripheral length, and the rubber hardness are combined, the rubber thickness t1 of the inner tie rubber layer 11 is set to 120% to 180% of the rubber thickness t2 of the outer tie rubber layer 12, and the inner tie rubber layer 11 The difference Δx between the peripheral length x1 and the peripheral length x2 of the outer tie rubber layer 12 is set to 10 mm to 100 mm, and the rubber hardness h1 of the inner tie rubber layer 11 is 120% to 150% of the rubber hardness h2 of the outer tie rubber layer 12 % Is preferably set.

  The tire size is 195 / 65R15, and has a basic structure common to FIGS. 1 to 4, and for the partial tie rubber layer, the rubber thickness t1 of the inner tie rubber layer, the rubber thickness t2 of the outer tie rubber layer, and the rubber thickness t2 Ratio of rubber thickness t1 (t1 / t2 × 100%), peripheral length x1 of inner tie rubber layer, peripheral length x2 of outer tie rubber layer, peripheral length x1 of inner tie rubber layer and peripheral length x2 of outer tie rubber layer The ratio Δx, the rubber hardness h1 of the inner tie rubber layer, the rubber hardness h2 of the outer tie rubber layer, and the ratio of the rubber hardness h1 to the rubber hardness h2 (h1 / h2 × 100%) are set as shown in Tables 1 to 3, respectively. 45 types of pneumatic tires of Example 1, Comparative Examples 1 to 7, and Examples 1 to 37 were produced.

  Conventional example 1 is an example in which a full tie rubber layer is provided. The full-tie rubber layer has a rubber thickness of 0.5 mm, a rubber hardness of 60, and a peripheral length of 420 mm (the total length along the tire inner surface from the bead toe inside the vehicle to the bead toe outside the vehicle).

  In all of Comparative Examples 1 to 7 and Examples 1 to 37, the end portion on the tire equator side of each partial tie rubber layer is disposed at a position 10 mm inward in the tire width direction from the outermost end portion in the tire width direction of the belt layer. ing.

  About these 45 types of pneumatic tires, the tire weight, rolling resistance, and dry braking performance were evaluated by the following evaluation methods, and the results are also shown in Tables 1 to 3.

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 “99” or more, it means that the tire weight is sufficiently small while maintaining the conventional level.

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.

Dry braking performance Each test tire is assembled to a wheel with a rim size of 15 x 6 J, mounted on a test vehicle with a displacement of 1.5 L with an air pressure of 210 kPa, and the test driver starts at a speed of 100 km / h on a test course consisting of a dry road surface. The distance until stopping was measured 5 times, and the average value (average stopping distance) was obtained. The evaluation result was shown by the index | exponent which sets the reciprocal number of the average stop distance of the prior art example 1 to 100. A larger index value means a shorter average stop distance and better dry braking performance. If the index value is “95” or more, it means that the conventional level is maintained and sufficient dry braking performance is obtained.

  As is apparent from Tables 1 to 3, all of Examples 1 to 37 reduced the tire weight and rolling resistance while maintaining dry braking performance as compared with Conventional Example 1. In particular, in Examples 10 to 30 in which two or more parameters of rubber thickness, peripheral length, and rubber hardness are set in a suitable range, dry steering stability performance is improved while maintaining or reducing tire weight and rolling resistance. Improved over Example 1.

  On the other hand, although Comparative Example 1 has a partial tie rubber layer, the dry steering stability performance is lower than that of Conventional Example 1 because the inner tie rubber layer and the outer tie rubber layer are the same. In Comparative Examples 2-3, the tire weight and rolling resistance could not be reduced because the inner tie rubber layer was too thick relative to the outer tie rubber layer. In Comparative Example 4, since the inner tie rubber layer was not sufficiently longer than the outer tie rubber layer, the dry steering stability performance could not be maintained. In Comparative Example 5, since the inner tie rubber layer was too long with respect to the outer tie rubber layer and reached the vicinity of the bead portion, the tire weight and rolling resistance could not be reduced. In Comparative Example 6, since the inner tie rubber layer was not sufficiently hard with respect to the outer tie rubber layer, the dry steering stability performance could not be maintained. In Comparative Example 7, since the inner tie rubber layer was extremely harder than the outer tie rubber layer, the rolling resistance could not be reduced, and the rolling resistance was comparable to that of Conventional Example 1.

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 Inner tie rubber layer 12 Outer tie rubber layer CL Tire equator

Claims (6)

A mounting direction with respect to the vehicle is specified, and a tread portion that extends in the circumferential direction of the tire and forms an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and an inner side in the tire radial direction of these sidewall portions A pair of bead portions, a carcass layer is mounted between the pair of bead portions, a belt layer is disposed on the outer periphery side of the carcass layer in the tread portion, and the tire inner surface along the carcass layer. A pneumatic tire in which an inner liner layer is disposed, and partial tie rubber layers are selectively disposed 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. In
The end of each partial tie rubber layer on the tire equator side is disposed in the range of 0 mm to 15 mm inward in the tire width direction from the outermost end of the belt layer in the tire width direction, and is disposed on the vehicle inner side of the partial tie rubber layer. The inner tie rubber layer and the outer tie rubber layer disposed outside the vehicle among the partial tie rubber layers have different rubber thicknesses, and the rubber thickness t1 of the inner tie rubber layer is 120 which is the rubber thickness t2 of the outer tie rubber layer. % To 200%, a pneumatic tire.   The inner tie rubber layer and the outer tie rubber layer have different peripheral lengths, and a difference Δx between the inner tie rubber layer peripheral length x1 and the outer tie rubber layer peripheral length x2 is 5 mm to 30 mm. The pneumatic tire according to claim 1.   The rubber hardness of the inner tie rubber layer is different from that of the outer tie rubber layer, and the rubber hardness h1 of the inner tie rubber layer is 105% to 150% of the rubber hardness h2 of the outer tie rubber layer. 2. The pneumatic tire according to 2. A mounting direction with respect to the vehicle is specified, and a tread portion that extends in the circumferential direction of the tire and forms an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and an inner side in the tire radial direction of these sidewall portions A pair of bead portions, a carcass layer is mounted between the pair of bead portions, a belt layer is disposed on the outer periphery side of the carcass layer in the tread portion, and the tire inner surface along the carcass layer. A pneumatic tire in which an inner liner layer is disposed, and partial tie rubber layers are selectively disposed 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. In
The end of each partial tie rubber layer on the tire equator side is disposed in the range of 0 mm to 15 mm inward in the tire width direction from the outermost end of the belt layer in the tire width direction, and is disposed on the vehicle inner side of the partial tie rubber layer. The inner tie rubber layer and the outer tie rubber layer disposed outside the vehicle among the partial tie rubber layers have different peripheral lengths, and the peripheral length x1 of the inner tie rubber layer and the peripheral length x2 of the outer tie rubber layer A pneumatic tire characterized in that the difference Δx is 5 mm to 30 mm.   The rubber hardness h1 is different between the inner tie rubber layer and the outer tie rubber layer, and the rubber hardness h1 of the inner tie rubber layer is 105% to 150% of the rubber hardness h2 of the outer tie rubber layer. The described pneumatic tire. A mounting direction with respect to the vehicle is specified, and a tread portion that extends in the circumferential direction of the tire and forms an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and an inner side in the tire radial direction of these sidewall portions A pair of bead portions, a carcass layer is mounted between the pair of bead portions, a belt layer is disposed on the outer periphery side of the carcass layer in the tread portion, and the tire inner surface along the carcass layer. A pneumatic tire in which an inner liner layer is disposed, and partial tie rubber layers are selectively disposed 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. In
The end of each partial tie rubber layer on the tire equator side is disposed in the range of 0 mm to 15 mm inward in the tire width direction from the outermost end of the belt layer in the tire width direction, and is disposed on the vehicle inner side of the partial tie rubber layer. The inner tie rubber layer and the outer tie rubber layer disposed outside the vehicle among the partial tie rubber layers have different rubber hardness, and the rubber hardness h1 of the inner tie rubber layer is 105% to 150% of the rubber hardness h2 of the outer tie rubber layer. %, A pneumatic tire characterized by

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