JP4368968B2 - Pneumatic tire - Google Patents

Description

【００４６】
表１に記載した試験結果は、各タイヤを８ＪＪのリムに組み、規定内圧２．４ｋｇｆ／ｃｍ² を充填してから、規定最大負荷能力（６５０ｋｇｆ）の７０％である４５０ｋｇｆの質量を負荷し、セーフティウォークを貼り付けたフラットベルト式試験機を用いて、速度５０ｋｍ／ｈ、タイヤの進行方向と回転面とのずれ（スリップアングル）を１°とした条件下で、タイヤに生じるコーナリングフォース（ＣＦ）を測定したものである。
比較例のタイヤのコーナリングフォース（ＣＦ＝１８０．６ｋｇｆ）を１００としたときの指数で示すこの測定結果では、参考例１，２および実施例の各タイヤにおけるコーナリングフォースの増加が確認された。
【００４７】
また、比較例、参考例および実施例のタイヤを供試タイヤとし、これらタイヤを２５００ｃｃの前輪駆動車（国産スポーツタイプ乗用車）のテスト車両に装着し、テストドライバーを含む乗員２名で６０〜１２０ｋｍ／ｈの速度範囲で直進走行、レーンチェンジ走行等を実施し、フィーリングによるそれぞれの走行結果を纏めて評価した。
性能評価は、比較例のタイヤをコントロールタイヤとして１０点満点で評点付けを行い、参考例および実施例を、比較例との対比で±１０段階の数値によった。もちろんプラス側で値が大なるほど良い。
この結果によれば、参考例１，２および実施例のタイヤはともに、直進安定性の大幅な向上が得られており、なかでも、実施例のタイヤでは、コーナリングフォースの増加と併せて、最もすぐれた直進安定性が得られた。
【００４８】
【発明の効果】
上記実施例からも明らかなように、この発明によれば、車両の旋回走行時のコーナリングフォースを有効に増大させて操縦性を高めることができ、併せて、直進安定性をもまた有利に向上させることができる。
【図面の簡単な説明】
【図１】 発明の実施の形態をタイヤのリム組み状態で示す幅方向断面図である。
【図２】 サイドウォール部補強部材の構成態様例を示す拡大断面図である。
【図３】 右旋回時の左輪タイヤの変形挙動およびフットプリントを示す説明図である。
【図４】 左輪タイヤの補強層コードの配向方向がもたらす影響を示す部分側面図である。
【符号の説明】
１ トレッド部
２ｉ，２ｏ サイドウォール部
３ｉ，３ｏ ビード部
４ ホイールリム
５ ラジアルカーカス
５ａ 巻上げ部
５ｂ 本体部分
６ ビードコア
７ ベルト
８ｉ，８ｏ 補強部材
９ ビードフィラ
１０ａ，１０ｂ，１０ｃ コード補強層[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a pneumatic tire with improved maneuverability, and advantageously increases the cornering force as a force against the centrifugal force when the vehicle is turning.
[0002]
[Prior art]
  Cornering force, in particular, the cornering power, which is a linear gradient in the region where the tire slip angle is small and the cornering force increases linearly, can be increased by increasing the cornering force even if the slip angle changes slightly. It can be greatly changed to provide sharp steering responsiveness, and a large cornering force can be generated to enable the vehicle to turn with a slight steering operation. Also, the posture of the vehicle can be changed against disturbances such as crosswinds. This will greatly improve the performance of the tires, for example, by making the tires small and enabling stable driving.
[0003]
  By the way, it is known that this cornering power is influenced by the tire filling air pressure, the width of the applied rim, the cross-sectional shape of the tire, the tread rigidity, the tire reinforcing structure, and the like. The higher the filling air pressure, the wider the rim width, the flatter the tire cross-sectional shape, and the higher the cornering power in the radial structure than in the bias structure.
[0004]
  Therefore, in the past, in response to the demand for further improvement in vehicle maneuverability accompanying the development of highway networks in recent years and the further enhancement of vehicle performance, generally one or more of the above-mentioned matters are required. By appropriately combining them, the cornering power is increased as required.
[0005]
[Problems to be solved by the invention]
  However, in such a prior art, the cornering power is increased in units of the entire tire. For example, when the cornering power is increased with a belt or other tire reinforcing structure, the reinforcing structure of each component part , While maintaining symmetry with respect to the tire equator line, where it is advantageous to make each component of each tire function for increased cornering power. No consideration of was paid.
[0006]
  Therefore, in the prior art, it is difficult to say that the functions of each component of the tire are sufficiently drawn out in order to increase the cornering power. For this reason, in realizing the required cornering power, the weight and cost of the tire are increased. There is a problem that the yield of the material is inevitably lowered.
[0007]
  The object of the present invention is to solve such problems of the prior art, and the purpose of the invention is to equally reinforce similar functional parts in one tire together. Rather than paying particular attention to the deformation mode of the tire during turning of the vehicle, especially the ground contact mode of the tread surface, the reinforcement structure of the same functional part of a single tire is changed relatively, and the reinforcement structure Is made asymmetric with respect to the tire equator, effectively increasing the cornering power and directly the cornering force without the disadvantages of tire weight and cost, material yield, etc. It is to provide a further improved pneumatic tire.
[0008]
[Means for Solving the Problems]
  The pneumatic tire according to the present invention is provided with a tread portion and a pair of sidewall portions extending radially inward from both side portions of the tread portion, and a bead portion is continuously provided at a radially inner end of each sidewall portion. In addition, a carcass that reinforces each of these portions is disposed, a belt that reinforces the tread is disposed on the outer peripheral side of the crown portion of the carcass, and a reinforcing member is disposed on the sidewall portion. Thus, the rigidity of the reinforcing member disposed on the sidewall portion with respect to the effect of the load on the tire is larger at the sidewall portion located inside the vehicle than at the sidewall portion located outside the vehicle.In addition, each reinforcing member arranged on each side wall portion is composed of a total of three cord reinforcing layers, each of which is folded back from the inside to the outside in the tire width direction around the bead core, and is folded around the bead core. The cords of the three cord reinforcement layers are extended so as to cross each other, except for the folded portion of the cord reinforcement layer to the outside in the tire width direction, and each cord reinforcement layer is viewed from the side of the tire. The extension angle of the cord with respect to the virtual radial line segment is set to be smaller than 45 degrees, larger than 45 degrees and smaller than 45 degrees in order from the inner layer side at the side wall portion located inside the vehicle with 45 degrees as a boundary. In addition, the side wall portion located on the outside of the vehicle is, in order from the inner layer side, larger than 45 degrees, smaller than 45 degrees, and larger than 45 degrees.Is.
[0009]
  When turning a vehicle, with conventional tires, particularly with respect to the grounding of the tire located outside the turn, the tire portion located outside the vehicle contributes effectively to supporting the load and causes deformation of the sidewall portion. While the ground is greatly grounded below, not so much load acts on the inner part of the vehicle, and the tread part is distorted inward of the turning, so the tread tread part located inside the vehicle is located outside. As a result, the contact area of the inner part of the vehicle is smaller than that of the outer part and the overall contact area is also reduced. There was a limit.
[0010]
  On the other hand, in the tire according to the present invention, the side wall portion reinforcing member for the side wall portion located on the inner side of the vehicle, and thus the side wall portion itself, has the bending rigidity against the action of the load. Therefore, when the load acting on the tire portion located inside the vehicle decreases during the turning of the vehicle as described above, the side wall portion on the side thereof Based on high rigidity, elastically returns to the original shape side, and at the same time, it functions to effectively prevent a decrease in the contact area of the tread tread surface against the distortion of the tread portion toward the inside of the turn. The ground contact area of the entire tire can be secured larger than that of the conventional tire, and as a result, the cornering force is effectively increased and the maneuverability is advantageously improved. It can be.
[0011]
  By the way, in this tire, it is not necessary to take special measures for increasing the flexural rigidity in the side wall portion located outside the vehicle, and a conventional reinforcing structure sufficient to perform other functions is provided. Therefore, it is possible to eliminate disadvantages such as an increase in weight and cost of a tire and a decrease in material yield caused by applying extra reinforcement even when the cornering force is increased.
[0012]
  In such a tire, preferably, the reinforcing members disposed on the respective sidewall portions are configured symmetrically with respect to the tires positioned with a center line of the vehicle.
  According to this, each of the pair of tires separating the vehicle center line generates the same cornering force when turning left and right of the vehicle, so that both left and right turning performances are sufficiently equalized and the course is corrected. Performance and steering stability can be enhanced, and price tears and the like derived from the reinforcing structure can be advantageously offset to improve straight running performance and stability against disturbance.
[0013]
  Also, here, the required difference in flexural rigidity of the reinforcing members disposed on the respective sidewall portions of the one tire is at least one of the width of the reinforcing layer, the cord rigidity, and the number of cords to be driven, constituting the reinforcing member. Realize by making the side wall part located inside the vehicle larger than the side wall part located outside the vehicleYou can also.
[0014]
  By the way, each of these tiresReinforcing members arranged on the sidewalls cross the cords between the layersthreeConsists of one cord reinforcement layerDoing,Also,threeAt least one of the cord reinforcement layersTheFolded around the bead core from the inside to the outside in the tire width directionDo it.
  AndAlso,When the cord reinforcing layer is disposed around the bead core in this manner, except for the portion of the cord reinforcing layer that is folded outward in the tire width direction,threeThe cords of one cord reinforcement layer extend so as to cross each otherso,Strengthen the reinforcing action.
[0015]
  furtherIn this tire, eachReinforcement member placed on the side wall part, one piece around the bead coreFrom inside to outside in the tire width directionA side wall portion that is formed by a total of three cord reinforcement layers that are folded back, and that each cord reinforcement layer is located on the inner side of the vehicle with the cord extension angle with respect to a virtual radial line segment as viewed from the side of the tire being 45 degrees as a boundary. In order from the inner layer side, it is smaller than 45 degrees, larger than 45 degrees and smaller than 45 degrees, and in the side wall portion located outside the vehicle, it is larger than 45 degrees and 45 degrees sequentially from the inner layer side. By making it smaller and larger than 45 degrees, in the inner side wall portion, each cord of the two cord reinforcement layers extends close to the radial line segment, whereas the outer side wall portion Then, since the cords of the two cord reinforcement layers extend close to the circumferential line portion seen from the side of the tire, the bending rigidity of the sidewall portion located inside the vehicle is The number of over-de reinforcing layer, without the need to change the width and the like, can be increased than that of the outer vehicle.
[0016]
  Preferably, at least one cord orientation direction of the cord reinforcing layer located on the innermost side in the tire width direction and the cord reinforcing layer having the widest width among the reinforcing members disposed on the respective sidewall portions is directed to the vehicle. In a virtual deployment state of a tire with a mounting posture of, At each side wallBoth are going up to the right,, At each side wallBoth rise to the left.
[0017]
  Here, when inputting the driving force to the tire, in particular, the reinforcing layer cord of the sidewall portion located inside the vehicle can also exhibit high rigidity against the circumferential shear force based on the orientation direction thereof. Accordingly, the transmission efficiency of the driving force by the sidewall portion can be advantageously improved. Further, since this high rigidity contributes to an increase in the tread contact surface pressure, the cornering force can be further increased in combination with the increase in the contact area based on the bending rigidity described above.
[0018]
  On the other hand, the reinforcement layer cord of the sidewall portion located outside the vehicle hardly supports the circumferential shearing force with respect to the input of the driving force to the tire, and thereby the sidewall portion becomes large. Shear deformation will contribute to a further increase in the tread contact area and, consequently, the cornering force.
[0019]
  By the way, such orientation of the reinforcing layer cord can be performed in at least one of the innermost cord reinforcing layer and the widest cord reinforcing layer in the tire width direction, and the reinforcing layer is on the inner layer side. The tension is higher than the outer layer, the effect of orientation is greater, and the wider reinforcing layer is preferable in that the working range is wider and more reinforcing layer cords can exhibit the orientation function. .
[0020]
  Here, when one or a plurality of cord reinforcement layers folded around the bead core is provided, the cord reinforcement layer portion located on the innermost side in the tire width direction is used as the entire reinforcement member in the tire width direction. The cord reinforcement layer located on the innermost side of
  The reason is that the reinforcement layer folded around the bead core increases its strength by folding and strengthens the reinforcement effect.ofso,If such a reinforcing layer is arranged as an inner layer, the reinforcing effect is enhanced in synergy with the above-described tension increasing effect.
[0021]
  Further, in the above case, the cord reinforcing layer portion located on the innermost side in the tire width direction may be the widest cord reinforcing layer as the entire reinforcing layer, which widens the range of action of the layer with high tension by the inner layer. Therefore, it is suitable for enhancing the reinforcing effect.
[0022]
  The pneumatic tire of the present invention is mounted with a tread portion, a pair of sidewall portions extending radially inward from both side portions of the tread portion, and a bead portion provided continuously to the radially inner end of each sidewall portion. And a carcass that reinforces each of these parts, a belt that is disposed on the outer peripheral side of the crown part of the carcass, and a reinforcing member that is disposed on the sidewall part, and that is provided on the sidewall part. Pneumatic tires whose members have a deflection rigidity with respect to the action of a load on the tire at the side wall portion located on the inner side of the vehicle and larger than the side wall portion located on the outer side of the vehicle. Installed on the vehicle so that the configuration of the arranged reinforcing members is symmetric with respect to the center line of the vehicleIt is preferable to carry out by.
[0023]
  According to this, by making each of the tires paired to the left and right sufficiently perform the functions described above sufficiently, the turning performance in the left and right directions can be made substantially equal, and the course Modification performance and operationForStability can be sufficiently increased, and further, straightness and stability against disturbance can be improved.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below based on the drawings.
  FIG. 1 is a cross-sectional view in the width direction showing an embodiment of the present invention in a rim assembled state of a tire, in which 1 is a tread portion, and 2i and 2o are radially inward from both sides of the tread portion 1. Respective side wall portions extending, and 3i and 3o indicate bead portions continuous to the radially inner ends of the side wall portions 2i and 2o, respectively, and 4 indicates a wheel rim on which the bead portions 3i and 3o are seated. .
[0025]
  Here, for example, each of the above portions is reinforced across the bead cores 6 embedded in the bead portions 3i and 3o by a radial carcass 5 made of at least one ply of an organic fiber cord such as polyester cord or nylon cord, and the radial portion thereof. Each side portion of the carcass 5 is wound around the bead core 6 in the radial direction and fixed, and the tread portion 1 is reinforced by the belt 7 disposed on the outer peripheral side of the crown portion of the radial carcass 5.
[0026]
  The belt 7 is, for example, a two-layer steel cord crossing layer, a spirally wound wide layer of organic fiber cords disposed on the outer periphery thereof, and disposed on the outer peripheral side thereof at the side of the wide layer. This can also be composed of a spiral wound narrow layer of organic fiber cords.
[0027]
  Further, here, after specifying the mounting posture of the tire with respect to the vehicle, the side wall portion 2i that is positioned inside the vehicle, and in the figure, the reinforcement disposed from the bead portion 3i to the side wall portion 2i. The bending rigidity of the member 8i with respect to the action of the load on the tire is made larger than the bending rigidity of the reinforcing member 8o disposed in the same manner on the sidewall portion 2o located outside the vehicle.
[0028]
  Here, such a difference in flexural rigidity is, for example, at least of the number, width, cord rigidity, and cord driving number of reinforcing layers that are disposed in the respective sidewall portions 2i, 2o and constitute the reinforcing members 8i, 8o. One can be realized by making the side wall portion 2i inside the vehicle larger than the side wall portion 2o outside the vehicle.
[0029]
  More specifically, the reinforcing member 8i of the sidewall portion 2i on the vehicle inner side is disposed on the outer peripheral side of the bead core 6 as illustrated in an enlarged sectional view in FIG. Two cord reinforcing layers 10a and 10b disposed between the gradually decreasing bead filler 9 and the winding portion 5a of the carcass 5 and one reinforcing layer 10c folded around from the inner side to the outer side in the tire width direction around the bead core 6. In this case, the number of the cord reinforcing layers, the width of at least one cord reinforcing layer, the cord rigidity, and the number of cords to be corded of the reinforcing member 8o of the sidewall portion 2o that will be located outside the vehicle. Alternatively, by reducing the two or more as required, the flexural rigidity of the reinforcing member 8i on the vehicle inner side is increased as expected with respect to that of the outer reinforcing member 8o. It is possible.
[0030]
  Here, mainly, when the bead filler 9 that contributes to strengthening of the tire bead portions 3i, 3o is extended to the sidewall portions 2i, 2o, it is replaced with or added to the above. By adjusting at least one of the rubber hardness, thickness, and radial extension length of the bead filler 9 and / or adjusting the distance between the main body portion 5b and the winding portion 5a of the carcass 5, A stiffness difference can also be realized.
[0031]
  By the way, when the reinforcing member is composed of a plurality of cord reinforcing layers 10a, 10b, and 10c as shown in FIG. 2, at least one of them is tire width around the bead core 6 as shown in the figure. In order to make the reinforcing action more effective, it is preferable that the cords are folded from the inner side to the outer side and the cords are arranged so as to cross each other between the cord reinforcing layers.
[0032]
  In order to bring about the above-mentioned interlayer crossing of the reinforcing layer cord, the cord extension of one or a plurality of cord reinforcing layers folded around the bead core 6 in relation to the number of cord reinforcing layers disposed, etc. If the direction interferes with the required interlayer crossing, it is possible to allow the cord reinforcing layers to cross each other with the exception of the folded portion of the folded cord reinforcing layer outward in the tire width direction. It is preferable for further enhancing the function.
[0033]
  Here, the interlayer crossing as described above of the reinforcing layer cord is, for example, a total of three cord reinforcing layers in which the reinforcing members 8i and 8o disposed on the sidewall portions 2i and 2o are folded around the bead core. 10 a, 10 b, 10 c, each cord reinforcing layer 10 a, 10 b, 10 c is a side located on the inner side of the vehicle with a cord extending angle with respect to a virtual radial line segment in a side view of the tire as a boundary of 45 degrees In the wall portion 2i, sequentially from the inner layer side, smaller than 45 degrees, larger than 45 degrees and smaller than 45 degrees, and in the sidewall portion 2o located outside the vehicle, sequentially from the inner layer side from 45 degrees Large, smaller than 45 degrees, and larger than 45 degrees, and in this case, the reinforcement layer cord of the inner side wall portion 2i is connected to the radial line segment. By selecting the degree of contact, it is possible to increase the flexural rigidity of the reinforcing member 8i of the inner side wall portion 2i, and thus the inner side wall portion 2i itself, as expected with respect to that of the outer side wall portion. .
[0034]
  As described above, the bending rigidity of the reinforcing member 8i of the sidewall portion 2i of the tire that is located inside the vehicle with respect to the action of the load is reinforced to the sidewall portion 2o that is located outside the vehicle. The deformation behavior of the tire during turning of the vehicle when it is made larger than that of the member 8o will be described below in the case where the left wheel makes a right turn located outside the turn.
[0035]
  In such turning, as shown in FIG. 3A, the left wheel tire generates a cornering force CF as a force that opposes the centrifugal force in the right direction in the figure, and the generation of such a cornering force CF occurs. In general, the side wall 2o located outside the vehicle increases its own amount of bending deformation, while the side wall 2i located inside increases the amount of bending deformation of the load and the tread portion. It tends to decrease due to distortion in the inner direction of the turn.
[0036]
  For this reason, in the conventional tire in which the inner side wall portion has a flexural rigidity substantially equal to that of the outer side wall portion, the inner side wall portion is, as shown by the phantom line in the figure, the outer side wall portion. As a result, the contact state of the tread surface is greatly reduced as shown by the phantom line in FIG. 3B, particularly in the inner part of the vehicle. However, in the tire according to the present invention in which the bending rigidity of the reinforcing member 8i of the inner side wall portion 2i is increased, the inner side wall portion 2i has the original shape with respect to the reduction of the load on the inner side wall portion 2i due to the bias of the load. In addition, the inner side wall portion 2i effectively counters the action of the tensile force applied to the tread portion due to the inward turning of the tread due to the centrifugal force. As a result, the reduction of the contact area of the tread tread on the inner side of the vehicle is advantageously prevented, and the contact area is expanded to the range surrounded by the solid line in the figure. It will be effectively increased.
[0037]
  By the way, in the tire having the above-described configuration, the reinforcing members 8i and 8o disposed on the respective sidewall portions 2i and 2o are symmetric with respect to each other which form a pair with the vehicle center line therebetween. When configured, as described above, the left and right turning performance should be made sufficiently uniform, the course correction performance and the steering stability should be improved, and the straight running performance and stability against disturbance may be further improved. According to the method of the present invention, these can be obtained by changing the flexural rigidity of the reinforcing members 8i, 8o disposed on the sidewall portions 2i, 2o with respect to the action of the load on the tire, on the side wall portion located inside the vehicle. 2i, the tire formed larger than the side wall portion 2o located outside the vehicle is formed of reinforcing members 8i, 8o disposed on the respective side wall portions 2i, 2o. There versa when mounted on a vehicle so as to be symmetrical with respect to the center line of the vehicle.
[0038]
  In such a tire, more preferably, in addition to the flexural rigidity of the inner sidewall portion 2i, the circumferential shear rigidity with respect to the driving force of the tire is also made larger than that of the outer sidewall portion 2o, so that the inner sidewall portion The increase in the contact pressure of the tread surface portion adjacent to 2i is also guaranteed.
[0039]
  For this purpose, of the reinforcing members 8i, 8o disposed on the respective side wall portions 2i, 2o, at least one cord of the cord reinforcing layer located on the innermost side in the tire width direction and the widest cord reinforcing layer With the left wheel tire in a plan view with the orientation direction set in the virtual deployment state of the tire mounted on the vehicle and the traveling direction upward.In each side wall part 2i, 20Both are going up to the right,In each side wall part 2i, 20Both rise to the left.
[0040]
  In this case, a portion of the cord reinforcement layer folded around the bead core that is located on the inner side in the tire width direction is the cord reinforcement layer located on the innermost side in the tire width direction as a whole reinforcing member, and the tire width The portion located inside the direction is preferably the widest cord reinforcing layer as the entire reinforcing layer.
[0041]
  FIG. 4 is a partial side view showing such a cord orientation mode on the sidewall portion 2i inside the vehicle of the left wheel tire, when the tire rolls, and the thin line in the drawing indicates the cord extension at the inner sidewall portion 2i. The direction and the imaginary line indicate the cord extending direction in the outer side wall portion 2o.
[0042]
  As shown in the figure, a circumferential shearing force S is generated in the tire sidewall portion 2i that rotates counterclockwise and causes the vehicle to travel, due to the tire driving force and the road surface resistance. The cord (refer to the thin line) of the cord reinforcing layer disposed on the inner side wall portion 2i with respect to the shearing force S, and thus the main tensile direction resulting from the generation of the shearing force S, Under the relation, the reinforcing layer cord (refer to the phantom line) disposed on the outer sidewall portion 2o functions to exert a specific tensile strength and restrain the circumferential shear deformation of the sidewall portion 2i. Since the supporting function of the shear force S cannot be effectively exhibited, a relatively large circumferential shear deformation occurs in the outer side wall portion 2o.
[0043]
  For this reason, the contact pressure on the tread tread surface on the inside of the vehicle increases, and the contact area increases on the outside contact portion of the vehicle, and any of these can further increase the cornering force.
[0044]
【Example】
  A pneumatic radial tire for passenger cars with a size of 235 / 45ZR17, comparative exampleReference examplesAnd the basic composition of an Example follows FIG. 1 and 2, and a grounding shape and groove arrangement follow FIG.
  The carcass consists of two plies of 1000D / 2 polyester cord, and the belt is a 2x 1x5 steel cord crossing layer inclined at an angle of 22 ° to the tire equator line, and a 1260D / 2 nylon cord And a narrow spiral wound layer of the same cord.
  Table 1 shows a comparative exampleReference examples 1 and 2And the reinforcing member structure of the side wall part in an Example, etc. are shown.
[0045]
[Table 1]

[0046]
  The test results shown in Table 1 show that each tire is assembled on an 8JJ rim and the specified internal pressure is 2.4 kgf / cm.² And then load a mass of 450 kgf, which is 70% of the specified maximum load capacity (650 kgf), and use a flat belt type testing machine with a safety walk attached. The cornering force (CF) generated in the tire was measured under the condition that the deviation (slip angle) from the rotating surface was 1 °.
  ComparisonExampleIn this measurement result indicated by an index when the tire cornering force (CF = 180.6 kgf) is 100,Reference Examples 1 and 2 and ExamplesIncreased cornering force in each tire was confirmed.
[0047]
  Comparative exampleReference examplesThe tires of the examples were used as test tires, and these tires were mounted on a 2500cc front-wheel drive vehicle (domestic sports-type passenger car) test vehicle. Driving, lane change driving, etc. were carried out, and each driving result by feeling was evaluated collectively.
  For performance evaluation, the comparative tire is used as a control tire, and is rated with a maximum of 10 points.Reference examples andThe example was based on a numerical value of ± 10 steps in comparison with the comparative example. Of course, the larger the value on the plus side, the better.
  According to this result,Reference Examples 1, 2 andBoth of the tires of the examples showed a significant improvement in straight running stability.In particular, in the tires of the examples, the most excellent straight running stability was obtained together with an increase in cornering force.
[0048]
【The invention's effect】
  As is clear from the above-described embodiments, according to the present invention, the cornering force during the turning of the vehicle can be effectively increased to improve the maneuverability, and at the same time, the straight running stability is also advantageously improved. Can be made.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view in the width direction showing an embodiment of the invention in a tire rim assembly state.
FIG. 2 is an enlarged cross-sectional view showing a configuration example of a sidewall portion reinforcing member.
FIG. 3 is an explanatory diagram showing deformation behavior and footprint of a left wheel tire during a right turn.
FIG. 4 is a partial side view showing the influence of the orientation direction of the reinforcing layer cord of the left wheel tire.
[Explanation of symbols]
  1 Tread
  2i, 2o side wall
  3i, 3o bead
  4 Wheel rim
  5 Radial carcass
  5a Winding part
  5b Body part
  6 Bead core
  7 Belt
  8i, 8o Reinforcing member
  9 Bead Filler
  10a, 10b, 10c Cord reinforcement layer

Claims (6)

A tread portion, a pair of sidewall portions extending radially inward from both side portions of the tread portion, and a bead portion provided continuously to the radially inner end of each sidewall portion; A pneumatic tire comprising a carcass to be reinforced, a belt disposed on an outer peripheral side of a crown portion of the carcass, and a reinforcing member disposed on a sidewall portion,
Of the reinforcing member which is disposed in the sidewall portion, the deflection rigidity to the action of the load of the tire, the side wall portion located on the inner side of the vehicle, so as to be larger than the side wall portion located outside of the vehicle, each of the side Each reinforcing member disposed on the wall portion is composed of a total of three cord reinforcing layers, one of which is folded from the inside to the outside in the tire width direction around the bead core, and the cord reinforcing layer folded around the bead core, Except for the part that wraps outward in the tire width direction, the cords of the three cord reinforcement layers extend so as to cross each other, and each cord reinforcement layer has a virtual radial line segment as viewed from the side of the tire. The cord extension angle with respect to the side wall portion located inside the vehicle with 45 degrees as the boundary, sequentially from the inner layer side is smaller than 45 degrees, larger than 45 degrees, and 45 degrees Small city Further, the side wall portion located outside of the vehicle, sequentially from the inner side, larger than 45 degrees, the pneumatic tire comprising a larger than the small and 45 degrees above 45 degrees.   2. The pneumatic tire according to claim 1, wherein the reinforcing members disposed in the respective sidewall portions are configured symmetrically with respect to each other of the tires positioned with respect to the center line of the vehicle.   At least one of the width, the cord rigidity, and the number of cords to be reinforced of the reinforcing layer of the reinforcing member disposed on each side wall portion is a side wall portion located on the inner side of the vehicle. The pneumatic tire according to claim 1 or 2, wherein the pneumatic tire is enlarged. Of the reinforcing members disposed on the respective sidewall portions, a tire in which the cord orientation direction of at least one of the innermost cord reinforcing layer and the widest cord reinforcing layer in the tire width direction is attached to the vehicle. in the state of the virtual development, in plan view in which the moving direction and upward in the left wheel tire, and both upper right in each of the sidewall portion, the right wheel tire, according to claim 1 comprising as both left-side up in each of the sidewall portion The pneumatic tire according to any one of to 3 . The pneumatic reinforcement according to claim 4 , wherein the innermost portion of the cord reinforcing layer folded around the bead core is positioned as the innermost cord reinforcing layer in the tire width direction as a whole reinforcing member. tire. Cord reinforced layer folded around the bead cores, the pneumatic tire according to the portion located closest to the inner side in the tire width direction, the whole reinforcing layer to claim 4 or 5 most becomes as wide cord reinforcing layer.

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