JP2018177112A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire that can keep weight of the tire and rolling resistance low sufficiently while improving steering stability on a dry road surface.SOLUTION: In a pneumatic tire whose direction of mounting on a vehicle is designated, a winding-up height H1 of a folding-back part 4b inside the vehicle of a carcass layer 4 is set different from a winding-up height H2 of the folding-back part 4b outside the vehicle of the carcass layer 4, so that the winding-up heights H1 and H2 satisfy a relational expression of H1<H2. A partial tie rubber layer 40 is arranged exclusively across the whole area of a region other than respective tip parts of a pair of bead parts 3, between the carcass layer 4 and an inner liner layer 9.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pneumatic tire whose mounting direction to a vehicle is specified, and more particularly, to a pneumatic tire which makes it possible to maintain a sufficiently low tire weight and rolling resistance while improving the steering stability on a dry road surface. It relates to the tire.

  In recent years, in a pneumatic tire whose mounting direction to a vehicle is specified, it is desirable to make the structure of the tire different between the inner side of the vehicle and the outer side of the vehicle when mounted on the vehicle. In order to improve tire performance, see, for example, Patent Document 1). In this way, in the tire in which the structure is configured asymmetrically between the inner side and the outer side of the vehicle, the cornering power can be improved as the bending rigidity of the sidewall portion on the outer side of the vehicle becomes higher. By increasing the height, the steering stability on a dry road surface can be improved.

  However, the use amount of the carcass layer increases as the winding height of the carcass layer increases, and the tire weight and the rolling resistance are adversely affected. Therefore, the steering height is improved by increasing the winding height of the carcass layer as described above. There is a limit to trying to achieve the problem, and there is a problem that sufficient effects can not always be obtained. Therefore, in order to increase the winding height of the carcass layer on the outer side of the vehicle to improve the steering stability, a further improvement for maintaining the tire weight and the rolling resistance is required.

Japanese Patent Application Laid-Open No. 2007-088313

  An object of the present invention is to provide a pneumatic tire capable of maintaining a sufficiently low tire weight and rolling resistance while improving steering stability on a dry road surface.

  A pneumatic tire according to the present invention for achieving the above object comprises 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, and these sidewall portions A pair of bead portions disposed on the inner side in the tire radial direction, a carcass layer mounted between the pair of bead portions, and a belt layer disposed on the outer circumferential side of the carcass layer in the tread portion; A pneumatic tire having an inner liner layer disposed on the inner surface of the tire along the carcass layer, and in which the mounting direction with respect to the vehicle is designated, the side which is the inner side with respect to the vehicle when mounted on the vehicle When the vehicle outer side is the vehicle outer side when mounted on a vehicle, the winding height H1 of the folded-back portion of the carcass layer on the vehicle inner side and the carcass layer The winding heights H1 and H2 of the folded-back portions on both outer sides are different from each other, and the winding heights H1 and H2 satisfy the relationship of H1 <H2, and the pair of beads are between the carcass layer and the inner liner layer. A partial tie rubber layer is limitedly disposed over the entire area except for the respective tip portions of the part.

  In the pneumatic tire according to the present invention, since the winding height H2 of the carcass folded portion on the vehicle outer side is larger than the winding height H1 of the carcass folded portion on the vehicle inner side, the rigidity of the sidewall portion on the vehicle outer side can be increased. it can. As a result, it is possible to increase the cornering power in the sidewall portion outside the vehicle, and to improve the steering stability on a dry road surface. At this time, since the amount of use of the carcass layer is increased because the winding height H2 is large, there is a concern about the influence on the tire weight and rolling resistance, but as the tie rubber layer, the entire width between the carcass layer and the inner liner layer is covered. Since the tire weight is reduced and rolling resistance is reduced by adopting a partial tie rubber layer instead of the full tie rubber layer, tire weight and rolling resistance are improved even if the winding height H2 is large and the amount of use of the carcass layer is increased. Can be maintained.

  In the present invention, the difference between the winding heights H1 and H2 is preferably 5 mm to 30 mm. By setting the difference between the winding heights H1 and H2 in this manner, the rigidity of the sidewall portion on the outer side of the vehicle can be sufficiently and appropriately increased without deteriorating the tire weight and the rolling resistance. It is advantageous for achieving a well-balanced improvement in stability and reduction in tire weight and rolling resistance.

  In the present invention, the projection amount L1 of the partial tie rubber layer to the bead portion side with respect to the perpendicular P drawn from the outermost end of the belt layer in the tire width direction toward the inner liner layer is the perpendicular P and the inside of the tire. It is preferable that it is 0.25 times to 0.90 times the perimeter length L2 along the tire inner surface from the intersection point A with the surface to the tip point B of the bead toe. By setting the position of the end on 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 functions as a tie rubber layer (carcass cord Can be reliably and highly enhanced, which is advantageous for reducing tire weight and rolling resistance. In the present invention, the “protrusion amount” is a so-called periphery length measured along the extension direction of each tire component (partial tie rubber layer) in the tire meridian cross section.

In the present invention, the protrusion amount L1 _IN at the end on the vehicle inner side of the partial tie rubber layer is different from the protrusion amount L1 _OUT at the end on the vehicle outer side, and these protrusion amounts L1 _IN and L1 _OUT have a relationship of L1 _IN <L1 _OUT It is preferable that the difference between the protrusion amounts L1 _IN and L1 _OUT be 5 mm to 30 mm. Thus, by increasing the projection amount L1 _OUT on the vehicle outer side, the rigidity of the sidewall portion on the vehicle outer side can be enhanced also by the partial tie rubber layer, which is advantageous for enhancing the steering stability on a dry road surface. At this time, since the difference between the protrusion amounts L1 _IN and L1 _OUT is set to an appropriate range, the tire weight and the rolling resistance can be well maintained, and the improvement of the steering stability on the dry road surface and the tire weight It is advantageous to balance rolling resistance reduction in a balanced manner.

  At this time, it is preferable that the end portion on the vehicle outer side of the partial tie rubber layer and the folded back portion on the vehicle outer side overlap, and the overlapping amount D2 thereof is 5 mm to 20 mm. By thus overlapping the partial tie rubber layer and the folded portion on the vehicle outer side, the rigidity of the sidewall portion on the vehicle outer side can be further enhanced. In addition, since the overlapping amount D2 is set to an appropriate range, the tire weight and the rolling resistance can be well maintained.

  In the present invention, the thickness of the partial tie rubber layer is preferably 0.1 mm to 1.3 mm. By setting the thickness of the partial tie rubber layer in this manner, it is possible to sufficiently obtain the effect of improving the rigidity by the partial tie rubber layer without adversely affecting the tire weight and the rolling resistance. In the present invention, “rubber thickness” is an average thickness obtained by dividing the cross-sectional area of the partial tie rubber layer by the peripherial length of the partial tie rubber layer in the meridional cross section.

  In the present invention, the hardness of the rubber constituting the partial tie rubber layer is preferably 50 to 90. By setting the hardness of the partial tie rubber layer in this manner, it is possible to sufficiently obtain the effect of improving the rigidity by the partial tie rubber layer without adversely affecting the tire weight and the rolling resistance. The "hardness of rubber" in the present invention is a hardness (so-called JIS-A hardness) measured at a temperature of 20 ° C. according to JIS K6253 using a durometer type A.

1 is a meridional cross-sectional view of a pneumatic tire according to an embodiment of the present invention.

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

  As shown in FIG. 1, the pneumatic tire according to the present invention includes a tread portion 1 extending in the circumferential direction of the tire to form an annular shape, a pair of sidewall portions 2 disposed on both sides of the tread portion 1, and a side. A pair of bead portions 3 disposed on the inner side in the tire radial direction of the wall portion 2 is provided. In addition, in FIG. 1, CL shows a tire equator. The pneumatic tire has a designated mounting direction with respect to the vehicle. Specifically, the IN side of the figure is the side designated to be inside with respect to the vehicle when attached to the vehicle (hereinafter referred to as the vehicle inside), and the OUT side of the figure is attached to the vehicle when attached to the vehicle It is the side (hereinafter referred to as the vehicle outer side) designated to be on the outer side.

  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 outward from inside the vehicle around the bead cores 5 disposed in each bead portion 3. Further, a bead filler 6 is disposed on the outer periphery of the bead core 5, and the bead filler 6 is enclosed by the main body 4 a of the carcass layer 4 and the folded portion 4 b. Assuming that the winding height of the folding portion 4b inside the vehicle is H1 and the winding height of the folding portion 4b outside the vehicle is H2, the winding heights H1 and H2 are different from each other. These winding heights H1 and H2 satisfy the relationship of H1 <H2. That is, the winding height H2 of the folded portion 4b on the outer side of the vehicle is larger than the winding height H1 of the folded portion 4b on the inner side of the vehicle.

  A plurality of (two in the example of FIG. 1) 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 inclined with respect to the tire circumferential direction, and the reinforcing cords are disposed so as to cross each other between layers. In these belt layers 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set, for example, in the range of 10 ° to 40 °. Further, a belt reinforcing layer 8 (a pair of belt reinforcing layers 8 covering the both end portions of the belt layer 7 in the example of FIG. 1) 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 is set at an angle of, for example, 0 ° to 5 ° with respect to the tire circumferential direction. 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 an air permeation preventing performance, and prevents the air filled in the tire from permeating the outside of the tire.

  A tread rubber layer 10 is disposed on the outer circumferential side of the carcass layer 4 in the tread portion 1, and a side rubber layer 20 is disposed on the outer circumferential side (outside in the tire width direction) of the carcass layer 4 in the sidewall portion 2. A rim cushion rubber layer 30 is disposed on the outer peripheral side (outside in the tire width direction) of the carcass layer 4. The tread rubber layer 10 may have a structure in which two types of rubber layers having different physical properties (a cap tread rubber layer and an under tread rubber layer) are laminated in the tire radial direction.

  A partial tie rubber layer 40 is disposed between the inner liner layer 9 and the carcass layer 4. The tie rubber layer disposed between the inner liner layer 9 and the carcass layer 4 prevents the carcass cords from getting into the inner liner layer 9 when the unvulcanized pneumatic tire is inflated at the time of manufacturing the tire. In the tire after manufacture, it contributes to the air permeation preventing property and steering stability on a dry road surface, and conventionally, it is provided so as to cover the entire layer between the carcass layer 4 and the inner liner layer 9 However, the partial tie rubber layer 40 of the present invention is limitedly provided in the area excluding the tip end of the bead portion 3.

  Thus, the winding height H2 of the folded portion 4b of the carcass layer 4 on the vehicle outer side is larger than the winding height H1 of the folded portion 4b of the carcass layer on the vehicle inner side. Stiffness can be increased. As a result, it is possible to increase the cornering power in the sidewall portion 2 outside the vehicle, and to improve the steering stability on a dry road surface. At this time, the amount of use of the carcass layer 4 increases because the winding height H2 is large, so there is a concern about the influence on the tire weight and rolling resistance, but a partial tie rubber layer 40 is adopted as the tie rubber layer instead of the full tie rubber layer. Since the tire weight is reduced and the rolling resistance is reduced, the tire weight and the rolling resistance can be favorably maintained even if the winding height H2 is increased and the use amount of the carcass layer 4 is increased.

  At this time, if the winding heights H1 and H2 match or the magnitude relationship is reversed and H1> H2, the rigidity of the sidewall portion 2 outside the vehicle can not be increased, and the dry road surface can not be obtained. The effect of improving the steering stability is not obtained.

  In setting the winding heights H1 and H2 in the relationship of H1 <H2, the difference between the winding height H1 and the winding height H2 is preferably set to 5 mm to 30 mm, more preferably 10 mm to 20 mm. By setting the difference between the winding heights H1 and H2 in this manner, the rigidity of the sidewall portion on the outer side of the vehicle can be sufficiently and appropriately increased without deteriorating the tire weight and the rolling resistance. It is advantageous for achieving a well-balanced improvement in stability and reduction in tire weight and rolling resistance. At this time, if the difference between the winding heights H1 and H2 is smaller than 5 mm, the rigidity of the sidewall 2 outside the vehicle can not be sufficiently improved, and the effect of enhancing the steering stability is limited. If the difference between the winding heights H1 and H2 is greater than 30 mm, the amount of use of the carcass layer 4 increases, which adversely affects the tire weight and rolling resistance, making it difficult to sufficiently maintain these performances. The winding heights H1 and H2 are not particularly limited as long as the above relationship and difference are satisfied, but the winding height H1 is preferably set to, for example, 30% to 60% of the tire cross sectional height SH, and the winding height H2 May be set to, for example, 50% to 90% of the tire cross-sectional height SH.

  The partial tie rubber layer 40 has an end on each of the side wall portions 2 on the vehicle inner side and the vehicle outer side, but in order to reliably prevent the carcass cord from being caught in the inner liner layer 9 at the time of manufacturing the tire, each end It is preferable for the belt layer to sufficiently protrude toward the bead portion from the outermost end in the tire width direction of the belt layer. Specifically, the protrusion amount L1 to the bead portion 3 side of the partial tie rubber layer 40 with respect to the perpendicular P drawn from the outermost end of the belt layer 7 in the tire width direction toward the inner liner layer 9 corresponds to the perpendicular P and the inside of the tire. It is preferable to increase 0.25 to 0.90 times, more preferably 0.30 to 0.70 times the length of the peripherial length L2 along the tire inner surface from the intersection point A with the surface to the tip point B of the bead toe . By setting the position of the end of the partial tie rubber layer 40 in this manner, the partial tie rubber layer 40 that does not cover the entire width between the carcass layer 4 and the inner liner layer 9 functions as a tie rubber layer (carcass cord Can be reliably and well exhibited, which is advantageous for reducing tire weight and rolling resistance. At this time, if the protrusion amount L1 is smaller than 0.25 times the periferri length L2, the area covered by the partial tie rubber layer 40 becomes narrow, and the effect of preventing carcass cord penetration can not be sufficiently obtained. If the protrusion amount L1 is larger than 0.90 times the periferri length L2, the usage amount of the partial tie rubber layer 40 increases and becomes substantially equal to the full tie rubber layer, so the tire weight and rolling resistance are adversely affected. It becomes difficult to sufficiently maintain these performances.

  The protrusion amount L1 of the partial tie rubber layer 40 not only satisfies the above range, but is preferably 15 mm or more. As a result of intensive research on the arrangement of the partial tie rubber layer 40 in the case of employing the partial tie rubber layer 40, the inventor of the present invention obtains air permeation prevention performance and steering stability equivalent to those of a pneumatic tire having a conventional full tie rubber layer. The partial tie rubber layer 40 is at least a specific area near the outermost end of the belt layer 7 in the tire width direction (the position of the perpendicular P and the position of 15 mm along the partial tie rubber layer 40 from the perpendicular P to the bead portion 3 It has been found that it is preferable to cover the region between), and by setting the protrusion amount L1 to 15 mm or more as described above, this region can be reliably covered by the partial tie rubber layer 40. It is advantageous to maintain air permeation resistance and steering stability at a high level. At this time, if the protrusion amount L1 is less than 15 mm, the above-mentioned region can not be covered, and it becomes difficult to maintain the air permeation prevention property and the steering stability favorably.

The partial tie rubber layer 40 may have a line symmetrical structure with respect to the tire equator CL, but the end position of the partial tie rubber layer 40 may be different between the vehicle inner side and the vehicle outer side. That is, the protrusion amount L1 _IN at the end portion inside the vehicle of the partial tie rubber layer is different from the protrusion amount L1 _OUT at the end portion outside the vehicle, and these protrusion amounts L1 _IN and L1 _OUT satisfy the relationship of L1 _IN <L1 _OUT Is preferred. Thus, by increasing the projection amount L1 _OUT on the vehicle outer side, the rigidity of the sidewall portion 2 on the vehicle outer side can be enhanced also by the partial tie rubber layer 40, which is advantageous for enhancing the steering stability on a dry road surface. . At this time, the difference between the protrusion amount L1 _IN and the protrusion amount L1 _OUT is preferably 5 mm to 30 mm, more preferably 15 mm to 25 mm. By setting the difference between the protrusion amounts L1 _IN and L1 _{OUT in} a suitable range as described above, the tire weight and the rolling resistance can be well maintained, and the improvement of the steering stability on the dry road surface and the tire weight and the rolling can be achieved. It is advantageous for achieving a well-balanced balance with the reduction of resistance. At this time, if the difference between the protrusion amounts L1 _IN and L1 _OUT is smaller than 5 mm, the rigidity of the sidewall portion 2 outside the vehicle can not be sufficiently improved, and the effect of enhancing the steering stability is limited. If the difference between the projecting amounts L1 _IN and L1 _OUT is larger than 30 mm, the usage of the partial tie rubber layer 40 (particularly the partial tie rubber layer 12 on the vehicle outer side) increases, which adversely affects the tire weight and rolling resistance. It becomes difficult to maintain sufficient performance.

  As described above, when the partial tie rubber layer 40 has an asymmetrical structure with respect to the tire equator CL, the end portion on the vehicle outer side of the partial tie rubber layer 40 overlaps the folded portion 4b of the carcass layer 4 on the vehicle outer side. The amount D2 is preferably 5 mm to 20 mm, more preferably 8 mm to 12 mm. As described above, by overlapping the partial tie rubber layer 40 and the folded portion 4b of the carcass layer 4 outside the vehicle, the rigidity of the sidewall 2 outside the vehicle can be further enhanced. Further, since the perimeter length x2 and the overlapping amount D2 are set in appropriate ranges, the tire weight and the rolling resistance can be well maintained. At this time, if the periferri length x2 is smaller than 30 mm, the partial tie rubber layer 12 itself on the outer side of the vehicle becomes small, so that the function as the tie rubber layer (preventing carcass cord penetration) can not be sufficiently obtained. The rigidity improvement effect by the layer 40 is also limited. If the perimeter distance x2 is greater than 120 mm, the amount of use of the partial tie rubber layer 12 on the outer side of the vehicle will increase, so the tire weight and rolling resistance will be adversely affected, making it difficult to maintain these performances sufficiently. If the overlapping amount D2 is smaller than 5 mm, the effect of the rigidity improvement by overlapping the partial tie rubber layer 40 and the folded portion 4b of the carcass layer 4 can not be sufficiently obtained. If the overlapping amount D2 is larger than 20 mm, the usage amount of the partial tie rubber layer 40 and / or the folded back portion 4b of the carcass layer 4 becomes large, so the tire weight and rolling resistance are adversely affected, and these performances are sufficiently maintained. It becomes difficult.

  It is not necessary for the partial tie rubber layer 40 and the folded back portion 4b of the carcass layer 4 to overlap on the vehicle inside. Rather, in view of the rigidity balance of the sidewall 2 on the vehicle inner side and the vehicle outer side, as illustrated, the tire radial direction inner end of the partial tie rubber layer 40 and the tire radial outer end of the folded portion 4 b of the carcass layer 4 And should be separated. Assuming that the separation distance between the tire radial direction inner end of the partial tie rubber layer 40 and the tire radial direction outer end of the folded portion 4b of the carcass layer 4 is D1, the separation distance D1 is preferably 5 mm to 20 mm. When the partial tie rubber layer 40 and the folded back portion 4b of the carcass layer 4 overlap inside the vehicle, the overlapping amount is preferably smaller than the overlapping amount D2 outside the vehicle.

  The thickness T of the partial tie rubber layer 40 is preferably 0.1 mm to 1.3 mm, more preferably 0.1 mm to 1 mm, in order to fully exhibit at least the function as a tie rubber layer (preventing carcass cord penetration). It should be .1 mm. By setting the thickness T of the partial tie rubber layer 40 in this manner, the effect of improving the rigidity by the partial tie rubber layer 40 can be sufficiently obtained without adversely affecting the tire weight and the rolling resistance. At this time, if the thickness T of the partial tie rubber layer 40 is smaller than 0.1 mm, the reinforcing effect by the partial tie rubber layer 40 can not be sufficiently obtained. If the thickness T of the partial tie rubber layer 40 is greater than 1.3 mm, the amount of use of the partial tie rubber layer 40 (particularly the partial tie rubber layer 12 on the vehicle outer side) increases, which adversely affects the tire weight and rolling resistance. It becomes difficult to sufficiently maintain these performances.

  The hardness of the partial tie rubber layer 40 is preferably 50 to 90, more preferably 55 to 80, in order to sufficiently exert at least the function as the tie rubber layer (preventing the penetration of the carcass cords). By setting the hardness of the partial tie rubber layer 40 in this manner, the effect of improving the rigidity by the partial tie rubber layer 40 can be sufficiently obtained without adversely affecting the tire weight and the rolling resistance. At this time, if the hardness of the partial tie rubber layer 40 is less than 50, the reinforcing effect by the partial tie rubber layer 40 can not be sufficiently obtained. If the hardness of the partial tie rubber layer 40 is greater than 90, the tire weight and rolling resistance will be adversely affected, making it difficult to sufficiently maintain these performances.

The tire size is 195 / 65R15, has the basic structure shown in FIG. 1, and the size relationship of the winding height of the folded portion of the carcass layer, the ratio H1 of the winding height of the folded portion inside the vehicle to the tire cross section height H1 / SH, ratio H2 / SH of winding height of folded portion outside vehicle to height of tire cross section, difference H1-H2 of winding height, structure of tie rubber layer, projection amount L1 _IN / L2 of vehicle inside with respect to periferri length L2 , periphery length outboard protrusion amount with respect of L2 L1 _OUT / L2, the difference L1 _iN -L1 _OUT amount of projection, the overlap amount D2 of the vehicle inner side of the folded portion and the portion tie rubber layer, a rubber thickness of a portion tie rubber layer T, Thirty-five types of pneumatic tires of Conventional Example 1, Comparative Examples 1 and 2, and Examples 1 to 32 in which the rubber hardness of the partial tie rubber layer was set as shown in Tables 1 to 3 were produced.

  In addition, about the column of "structure of a tie rubber layer" of Tables 1-3, when a tie rubber layer was a full tie rubber layer, it described as "full", and when it was a partial tie rubber layer, it described as "a part."

  With respect to these 35 types of pneumatic tires, the tire weight, rolling resistance, and steering stability on a dry road surface (steering stability) 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 result is indicated by an index where the reciprocal of the measured value of Conventional Example 1 is 100. The larger the index value, the smaller the tire weight.

Rolling resistance Each test tire is assembled to a wheel of rim size 15 × 6 J, and rolling under the condition of air pressure 210 kPa, load 4.82 kN, speed 80 km / h using a drum testing machine with a drum diameter of 1707.6 mm according to ISO 28580 The resistance was measured. The evaluation result is indicated by an index where the reciprocal of the measured value of Conventional Example 1 is 100. The larger the index value, the lower the rolling resistance.

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

  As is clear from Tables 1 to 3, all of Examples 1 to 32 improve steering stability while maintaining and reducing the tire weight and the rolling resistance, as compared with Conventional Example 1.

  On the other hand, in Comparative Example 1, although the steering stability can be improved because the winding height on the outer side of the vehicle is high, the tire weight and the rolling resistance can be sufficiently maintained since the full tie rubber layer is used as the tie rubber layer. I could not In Comparative Example 2, since the winding height inside the vehicle is large, the rigidity of the sidewall portion on the vehicle outer side can not be increased, and the steering stability can not be improved.

DESCRIPTION OF SYMBOLS 1 tread part 2 side wall part 3 bead part 4 carcass layer 4a main-body part 4b return part 5 bead core 6 bead filler 7 belt layer 8 belt reinforcement layer 9 inner liner layer 10 tread rubber layer 20 side rubber layer 30 rim cushion rubber layer 40 partial tie rubber Tier CL Tire Equatorial IN Vehicle Inside OUT Vehicle Outside

Claims (7)

A tread portion extending in the circumferential direction of the tire and forming an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the tire radial direction inner side of the sidewall portions A carcass layer mounted between the pair of bead portions, a belt layer disposed on the outer circumferential side of the carcass layer in the tread portion, and an inner liner layer disposed on the tire inner surface along the carcass layer And a pneumatic tire having a mounting direction specified for the vehicle,
When the side to be inside with respect to the vehicle is the inside of the vehicle when mounted to the vehicle and the side to be the outside of the vehicle is mounted to the outside of the vehicle when mounted to the vehicle, The winding height H1 and the winding height H2 of the folded back portion of the carcass layer on the vehicle outer side are different, and the winding heights H1 and H2 satisfy the relationship of H1 <H2, and the carcass layer and the inner liner layer In the pneumatic tire, a partial tie rubber layer is limitedly disposed over the entire area of the region excluding the tip portions of the pair of bead portions.   The pneumatic tire according to claim 1, wherein a difference between the winding heights H1 and H2 is 5 mm to 30 mm.   The amount L1 of protrusion of the partial tie rubber layer toward the bead portion with respect to the perpendicular P drawn from the outermost end of the belt layer toward the inner liner layer is the intersection of the perpendicular P with the inner surface of the tire The pneumatic tire according to claim 1 or 2, characterized in that it is 0.25 times to 0.90 times a length (periphery length L2) of the tire from A to the tip point B of the bead toe along the tire inner surface. The protrusion amount L1 _IN at the end on the vehicle inner side of the partial tie rubber layer is different from the protrusion amount L1 _OUT at the end on the vehicle outer side, and these protrusion amounts L1 _IN and L1 _OUT satisfy the relationship of L1 _IN <L1 _OUT. The pneumatic tire according to any one of claims 1 to 3, wherein a difference between the projection amounts L1 _IN and L1 _OUT is 5 mm to 30 mm.   The pneumatic tire according to claim 4, wherein an end portion of the partial tie rubber layer on the vehicle outer side and a folded portion on the vehicle outer side overlap, and an overlapping amount D2 thereof is 5 mm to 20 mm.   The thickness of the said partial tie-rubber layer is 0.1 mm-1.3 mm, The pneumatic tire in any one of the Claims 1-5 characterized by the above-mentioned.   The pneumatic tire according to any one of claims 1 to 6, wherein the hardness of the rubber constituting the partial tie rubber layer is 50 to 90.

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