JP4513233B2 - Pneumatic radial tire - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic radial tire, and more particularly to a pneumatic radial tire with improved high-speed durability.
[0002]
[Prior art]
Conventionally, for example, a belt edge reinforcing layer in which a reinforcing cord is spirally wound continuously at a constant pitch in the tire circumferential direction on the outer peripheral side of the end of the belt layer is arranged so as to enhance durability during high-speed running Pneumatic radial tires have been proposed. The belt edge reinforcement layer suppresses the lift of the belt layer end caused by the centrifugal force during high-speed rotation of the tire, thereby suppressing the occurrence of edge separation and improving the high-speed durability.
[0003]
However, the higher the performance of the vehicle, the higher the load on the tires. As mentioned above, the belt edge reinforcement that only wraps the reinforcement cord at a constant pitch alone will provide higher durability that matches the performance of the vehicle. Is getting harder.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a pneumatic radial tire with further improved high-speed durability.
[0005]
[Means for Solving the Problems]
The pneumatic radial tire of the present invention that achieves the above object includes a belt edge reinforcing layer in which a belt layer is disposed on the outer peripheral side of the carcass layer of the tread portion, and a reinforcing cord is wound around the end region of the belt layer in the tire circumferential direction. In the pneumatic radial tire in which the belt edge reinforcing layer is disposed, the belt edge reinforcing layer is disposed on the inner peripheral side of the belt layer and on the outer peripheral side of the carcass layer, and the winding density of the reinforcing cords of the belt edge reinforcing layer is determined. It is characterized by gradually increasing from the inner side in the width direction toward the end of the belt layer .
[0006]
The winding density of the reinforcing cords of the belt edge reinforcement layer as described above in the high to Turkey towards the tire width direction inner side to the belt layer end portion, the reinforcing cord lifting of the belt layer end portion by the centrifugal force at high speeds The amount used can be more effectively suppressed with the same amount or less than the conventional tire, so that high-speed durability can be improved.
[0007]
Another pneumatic radial tire of the present invention is a pneumatic radial tire in which a belt layer is disposed on the outer circumferential side of the carcass layer of the tread portion, and the end region of the belt layer and the innermost belt layer and the preceding carcass layer tire width belt edge reinforcement layer having a width extending from the tire width direction inner edge of the end portion to the tire width direction outside circumferential and set, the rigidity of the belt edge reinforcement layer from the tire width direction inner side between the It is characterized by being gradually raised toward the outside in the direction .
[0008]
Thus, the belt edge reinforcing layer is provided so as to extend the edge of the belt layer end so as to straddle the inside and outside of the tire width direction, and the rigidity of the belt edge reinforcing layer is increased from the inside in the tire width direction toward the outside in the tire width direction. In order to relieve stress applied to the edge of the belt layer during running, it improves load durability and effectively suppresses lifting of the belt layer end during high speed running to improve high speed durability. Can do.
[0009]
Further, since the rigidity of the belt edge reinforcing layer extending outward in the tire width direction from the edge of the belt layer is increased, the natural frequency of the tire due to deformation of the portion can be increased by the extended portion. As a result, road noise in the range of 200 to 400 Hz can be improved.
[0010]
In addition, since the rigidity in the end region of the tread can be increased without substantially increasing the in-plane bending rigidity, the cornering force at low loads can be increased, and as a result, the steering stability can be improved. It becomes possible.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0012]
FIG. 1 shows an essential part of the pneumatic radial tire of the present invention, where 1 is a tread portion, 2 is a carcass layer, and 3 is a belt layer. The carcass layer 2 is mounted between left and right bead portions (not shown), and both end portions thereof are folded around the bead core (not shown) from the inside to the outside of the tire. A plurality of belt layers 3 are arranged on the outer peripheral side of the carcass layer 2 of the tread portion 1.
[0013]
The belt layer 3 is composed of a wide first belt layer (innermost belt layer) 3A on the inner peripheral side and a narrow second belt layer 3B laminated on the outer peripheral side thereof, and the first belt layer 3A. A belt edge in which a rubber-coated reinforcing cord f is continuously wound spirally in the tire circumferential direction on the inner peripheral side of the end 3X of the belt layer 3 from the end 3a to the end 3b of the second belt layer 3B A reinforcing layer 4 is provided. Belt edge reinforcement layer 4 is wound density of the reinforcing cords f is Yes and higher gradually toward the belt layer end portion from the inner side in the tire width direction, of the end portions 3X of the belt layer 3 edge x (1 No. belt layer end portion 3a It becomes higher toward the edge side so that it becomes the maximum at the edge.
[0014]
As the reinforcing cord f of the belt edge reinforcing layer 4, a known cord used for a conventional belt edge reinforcing layer can be used. For example, an organic fiber cord such as a nylon cord or an aramid cord, or a metal such as a steel cord. A code can be used.
[0015]
Thus, by increasing the winding density of the reinforcing cord f of the belt edge reinforcing layer 4 on the edge x side of the belt layer end portion 3X, the amount of the reinforcing cord f used is the same as or less than that of the conventional tire during high speed running. Since the lift of the edge portion of the belt layer end portion 3X due to the centrifugal force can be suppressed more efficiently, the edge separation resistance of the belt layer can be improved even when the performance of the vehicle is improved. Accordingly, it is possible to improve durability during high-speed traveling. Since it is only necessary to change the winding density of the reinforcing cord f of the belt edge reinforcing layer 4, other performances are not adversely affected.
[0016]
Further, by arranging the belt edge reinforcement layer 4 on the end portion 3a in the circumferential side of the No. 1 belt layer 3A, the belt edge reinforcement layer 4 is for suppressing the floating of the belt layer end portion 3X via an adhesive to rubber since it has, since that can be placed on not the base Rutoejji reinforcing layer 4 stepwise, there is no such thing as cause the adverse effect on the high-speed durability due to the level difference.
[0017]
In the above embodiment, the belt edge reinforcing layer 4 is preferably wound with the reinforcing cord f at a winding density that compensates for the tension sharing ratio of the belt layer 3.
[0018]
The winding density of the reinforcing cord f is preferably 40/50 mm to 60/50 mm as an average value per winding width of 50 mm. When the winding density is lower than 40/50 mm, the reinforcing effect cannot be obtained. On the contrary, if it is higher than 60/50 mm, it is difficult to secure a sufficient amount of rubber for covering the reinforcing cord f.
[0019]
The belt edge reinforcing layer 4 is preferably extended outward from the edge x in the tire width direction in order to enhance the lifting suppression effect of the edge x of the belt layer 3. The winding density of the reinforcing cord of the extension is preferably lowered as the distance from the edge x increases. In particular, when the length of the extension portion in the tire width direction is 10 mm or more, the durability in the end region of the tread portion 1 having a large strain can be further improved by gradually reducing the winding density.
[0020]
It preferably to increase as the location of the edges x side of the reinforcing cords f of winding tension winding dense belt layer end portion 3X on the base Rutoejji reinforcing layer 4 during molding is good, and to increase thereby further the effect described above Can do.
[0021]
FIG. 4 shows an example of another pneumatic radial tire of the present invention. In this embodiment, a belt edge reinforcing layer 4 having a width extending from the inner side in the tire width direction to the outer side in the tire width direction of the edge x between the end portion 3a of the first belt layer 3A and the carcass layer 2 is circumferential. It is arranged. Belt edge reinforcement layer 4, as well as comprised of reinforcing cords e of the rubber-coated wound in the tire circumferential direction, by increasing the winding density of the reinforcing cords e toward the tire width direction inner side to the outer side in the tire width direction, the stiffness in the width direction of the belt edge reinforcement layer 4 toward the tire width direction inner side to the outer side in the tire width direction are gradually increased.
[0022]
As the reinforcing cord e of the belt edge reinforcing layer 4, a known cord used for a conventional reinforcing layer can be used. For example, an organic fiber cord such as a nylon cord or an aramid cord, or a metal cord such as a steel cord is used. Can be used.
[0023]
The belt edge reinforcing layer 4 that increases in rigidity from the inner side to the outer side in the tire width direction so as to extend from the inner side in the tire width direction to the outer side in the tire width direction of the edge x of the belt layer 3 as described above, Since the stress applied to x can be relaxed, the edge separation resistance of the belt layer 3 is improved, and the load durability can be increased. Further, since there is a belt edge reinforcing layer 4 in which the reinforcing cord e is wound around the end portion 3X of the belt layer 3, the lifting of the belt layer end portion 3X due to centrifugal force during high-speed rotation is suppressed, and high-speed durability is improved. be able to.
[0024]
In addition, by gradually increasing the rigidity in the width direction of the belt edge reinforcing layer 4 and extending outside the edge x of the belt layer 3 in the tire width direction , the natural vibration of the tire due to deformation of the portion by the extended portion. Because the number can be increased, the road noise from 200 Hz to 400 Hz can be maintained at the same level as that of a conventional tire with improved road noise, and the end of the tread portion 1 can be maintained without substantially changing the in-plane bending rigidity. Since the rigidity in the partial region can be increased, the cornering force at the time of low load is increased, thereby improving the steering stability.
[0025]
In the embodiment of FIG. 4 described above, the reinforcing cord e of the belt edge reinforcing layer 4 is preferably spirally wound in a range of approximately 0 ° to 15 ° in the tire circumferential direction. If the angle exceeds 15 °, it is difficult to obtain the above-described effect.
[0026]
The rubber covering the reinforcing cord e of the belt edge reinforcing layer 4 is preferably a rubber having a dynamic elastic modulus (initial strain 10%, amplitude ± 2%, the same applies hereinafter) E ′ at room temperature of 20 MPa or less. When the dynamic elastic modulus E ′ exceeds 20 MPa, the durability is lowered. The lower limit can be set to 2 MPa from the point of reinforcing effect.
[0027]
When the reinforcing cord e of the belt edge reinforcing layer 4 is covered with the rubber, the rubber is covered with a single dynamic elastic modulus E ′ or a plurality of types of rubbers having different dynamic elastic modulus E ′. It may be.
[0028]
The reinforcing cord e of the belt edge reinforcing layer 4 can be wound without being covered with rubber. In that case, it is preferable to insert a rubber layer having a substantially triangular cross section between the belt layer end 3X and the reinforcing cord e to avoid direct interference between the belt layer 3 and the vicinity of the edge.
[0029]
The belt edge reinforcing layer 4 is formed by continuously winding a single type of reinforcing cord e in the figure, but a plurality of different types of reinforcing cords e (for example, nylon cord and aramid cord) are wound. It can also be configured.
[0030]
Figure 5 shows another example of the pneumatic radial tire of FIG. 4, in place of the reinforcing cords e of the belt edge reinforcement layer 4 described above, toward the rigidity in the width direction from the tire width direction inside in the tire width direction outside It is composed of a gradually enlarged rubber layer. As the rubber constituting the rubber layer, the dynamic elastic modulus E ′ at room temperature is in the range of 10 MPa to 70 MPa, and increases toward the tire outer side.
[0031]
Even if the belt edge reinforcing layer 4 is constructed from the rubber layer having the rigidity changed in this way, the road noise in the range of 200 Hz to 400 Hz is improved with the conventional road noise while improving the load durability and the steering stability described above. Can be maintained at the same level as the worn tire.
[0032]
If the dynamic elastic modulus E ′ is less than 10 MPa, the rigidity becomes too low, and it becomes difficult to obtain the above-described effect. Conversely, if it exceeds 70 MPa, the durability is adversely affected.
[0033]
4 and 5 described above, the belt width W of the first belt layer 3A (a distance measured in the tire width direction parallel to the tire axis) with the inner end 4a from the edge x to the inner side in the tire width direction. Further, it is preferable that the outer end 4b is positioned within the range of 5 to 20% of the belt width W from the edge x to the outer side in the tire width direction.
[0034]
If the inner end 4a exceeds 30% of the belt width W, an unnecessary weight increase occurs. Conversely, if the inner end 4a is closer to the edge x than 5%, the reinforcing effect is not exhibited. If the outer peripheral edge 4b exceeds 20% of the belt width W, the durability is impaired. Conversely, if the outer peripheral edge 4b is closer to the edge x than 5%, the reinforcing effect is not exhibited. The most preferable position is such that the inner end 4a is 20% of the belt width W and the outer end 4b is 10% of the belt width W.
[0035]
Further, the belt edge reinforcement layer 4, it is possible to configure the tension winding when forming shapes with large as the tire width direction outside.
[0036]
That is, when the belt edge reinforcing layer 4 is configured by using the reinforcing cord e, the reinforcing cord e is wound at a substantially constant winding density, while the winding tension of the reinforcing cord e is set to the tire width when the belt edge reinforcing layer 4 is formed. by winding with high enough outward, it is to increase gradually toward the rigidity in the width direction of the belt edge reinforcement layer 4 from the tire width direction inside in the tire width direction outside.
[0037]
On the other hand, when the belt edge reinforcing layer 4 is composed of a rubber layer, particularly when short fibers made of organic fibers are blended, the rubber layer is composed of a single rubber having a dynamic elastic modulus E ′. When the edge reinforcing layer 4 is molded, the rubber layer is wound with the winding tension increased toward the outer side in the tire width direction, thereby gradually increasing the rigidity in the width direction of the belt edge reinforcing layer 4 from the inner side in the tire width direction toward the outer side in the tire width direction. Make it high.
[0038]
The effect similar to the above can be obtained also by changing the winding tension in this way. Of course, it may be combined with the embodiments of FIGS. 4 and 5 described above.
[0039]
【Example】
Example 1 , Comparative Examples 1 and 2 , Conventional Example 1
The tire size is common to 195 / 65R15 91H,
1 of arranging the belt edge reinforcement layer wound by increasing the winding density reinforcing cords made of nylon cords as edge side of the belt layer end portion between an innermost side of the belt layer end portion and the carcass layer the present invention tire 1 having the configuration shown, the outermost circumferential side of the belt layer end portion comparative tire 1 of the configuration shown in FIG. 2 for the same belt edge reinforcement layer and the present invention tires 1 and disposed on the outer peripheral side of the outermost side of the belt layer A belt edge reinforcing layer is arranged on the outer peripheral side of the end portion with a reinforcing cord made of nylon cord at the same winding density, and the winding tension is increased toward the edge side of the belt layer end portion in the range of 50 g / piece to 150 g / piece at the time of molding. A comparative tire 2 having the configuration shown in FIG. 3 and a conventional tire 1 in which a belt edge reinforcing layer in which the winding density of the reinforcing cord is fixed in the present invention 1 are arranged are prepared.
[0040]
The winding tension at the time of forming the belt edge reinforcing layer of the tire 1 of the present invention , the comparative tire 1 and the conventional tire 1 is 50 g / piece.
[0041]
When each of these test tires was subjected to a high-speed durability evaluation test under the measurement conditions shown below, the results shown in Table 1 were obtained.
[0042]
High-speed durability Each test tire is compliant with the 2001 JATMA Yearbook, JIS D-4230 with a drum diameter of 1707 mm, and after JIS high-speed durability test is completed, it is accelerated by 10 km / hr every 30 minutes until the tire breaks The test continued. The result was evaluated in five stages. The higher this value, the better the high speed durability.
[0043]
[Table 1]
[0044]
From Table 1, it can be seen that the tire 1 of the present invention and the comparative tires 1 and 2 can improve the high-speed durability. In particular, it can be seen that the tire 1 of the present invention can further improve the high speed durability by disposing the belt reinforcing layer between the innermost belt layer and the carcass layer.
[0045]
Examples 2-5 , Conventional Examples 2 , 3
The figure which arrange | positioned the belt edge reinforcement layer which made the tire size the same as Example 1, and made the winding density of the reinforcement cord which consists of nylon cords high in the tire width direction between the belt layer edge part of the innermost circumference and the carcass layer. the present invention tire 2 having the configuration shown in 4, the reinforcing cord in the present invention tire 2 the invention tire 3 coated with rubber 20 MPa, in the present invention tire 2 belt edge reinforcement layer in the range of 70MPa from 10MPa as the outer side in the tire width direction the present invention tire 4 in Fig. 5 which is composed of a high rubber layer stiffness, the belt edge reinforcement layer formed of a rubber layer of rubber of 50MPa in the present invention tire 4, tension 50g / 10mm~150g / 10mm wrapped during molding the present invention tire 5 was as high as the outer side in the tire width direction in a range of not in the present invention tire 2 provided belt edge reinforcement layer The conventional tire 3 is provided with a belt edge reinforcing layer in which a reinforcing cord made of nylon cord is continuously wound in the tire circumferential direction between the edge of the belt layer and the tire maximum width position in the next tire 2 and the conventional tire 2. Produced.
[0046]
In addition, the winding tension at the time of belt edge reinforcement layer formation of this invention tires 2-3 and the conventional tire 3 is 50 g / piece, and this invention tire 4 is 50 g / 10 mm.
[0047]
While each of these test tires was subjected to a high-speed durability evaluation test under the measurement conditions shown in Example 1, a load durability, road noise, and steering stability evaluation test was performed under the measurement conditions shown below. The result shown in 2 was obtained.
[0048]
Load durability Each test tire was tested in accordance with the specified load conditions of drum diameter 1707mm, JIS D-4230, JISMA 2001 version, and then the test was continued until the tire was destroyed by increasing the load every 20% / 5 hours. The results were evaluated on a five-point scale. The larger this value, the better the load durability.
[0049]
Road noise Each test tire was mounted on an actual vehicle, sensory evaluation of 5 trained panelists was performed, and the evaluation values of 5 levels were averaged. The larger this value, the better the road noise resistance.
[0050]
Steering stability Five panelists evaluated each test tire in an actual vehicle sensory test, and the average value of five persons was evaluated in five stages. The larger this value, the better the steering stability.
[0051]
[Table 2]
[0052]
From Table 2, the tires 2 and 3 of the present invention in which the winding density of the reinforcing cord of the belt edge reinforcing layer is increased toward the outer side in the tire width direction, while maintaining the road noise level equivalent to that of the conventional tire 3 with improved road noise, It can be seen that the performance, high-speed durability, and steering stability can be improved.
[0053]
The present invention tire 4 in which the belt edge reinforcing layer is composed of a rubber layer and the dynamic elastic modulus E ′ is increased toward the outer side in the tire width direction , and the present tire 5 in which the winding tension is increased toward the outer side in the tire width direction is also loaded. It can be seen that load durability and steering stability can be improved while securing road noise resistance equivalent to that of the conventional tire 3 with improved noise.
[0054]
【The invention's effect】
The pneumatic radial tire of the present invention as described above, by a high to Turkey as edge side of the belt layer end portion of the winding density of the reinforcing cords of the wound reinforcing cords in the tire circumferential belt edge reinforcement layer, more High high speed durability can be improved.
[0055]
Further, another pneumatic radial tire of the present invention has a belt edge reinforcing layer having a width extending from the inner side in the tire width direction to the outer side in the tire width direction of the edge of the end portion of the belt layer, By gradually increasing the rigidity of the belt edge reinforcing layer from the inner side in the tire width direction toward the outer side in the tire width direction , high-speed durability and load durability can be improved and road noise can be improved.
[Brief description of the drawings]
FIG. 1 is a tire meridian cross-sectional view showing a main part of a pneumatic radial tire of the present invention.
FIG. 2 is a tire meridian cross-sectional view showing the main part of a comparative tire corresponding to the pneumatic radial tire of FIG. 1;
FIG. 3 is a tire meridian cross-sectional view showing a main part of another comparative tire corresponding to the pneumatic radial tire of FIG. 1;
FIG. 4 is a tire meridian cross-sectional view showing the main part of another pneumatic radial tire of the present invention.
5 is a tire meridian cross-sectional view showing a main part of still another example of the pneumatic radial tire of FIG . 4; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tread part 2 Carcass layer 3 Belt layer 3A 1st belt layer 3B 2nd belt layer 3X, 3a, 3b End part 4 Belt edge reinforcement layer 4a Inner edge 4b Outer edge e, f Reinforcement cord x Edge

Claims (10)

In a pneumatic radial tire in which a belt layer is arranged on the outer periphery side of the carcass layer of the tread, and a belt edge reinforcing layer in which a reinforcing cord is wound in the tire circumferential direction is arranged in an end region of the belt layer, the belt edge reinforcement The layers are arranged on the inner peripheral side of the belt layer and on the outer peripheral side of the carcass layer, and the winding density of the reinforcing cords of the belt edge reinforcing layer is gradually increased from the inner side in the tire width direction toward the end of the belt layer . Pneumatic radial tire.   The pneumatic radial tire according to claim 1, wherein the winding density of the reinforcing cord of the belt edge reinforcing layer is maximized at an edge of the belt layer end portion.   The pneumatic radial tire according to claim 1 or 2, wherein an average winding density of the reinforcing cord is 40 to 60 pieces / 50 mm. The belt edge reinforcing layer is extended outward in the tire width direction from the edge of the belt layer end portion, and the winding density of the reinforcing cord of the extension portion is lowered as the distance from the edge of the belt layer end portion decreases. 3. A pneumatic radial tire according to 3. The pneumatic radial tire according to any one of claims 1 to 4 , wherein the winding tension of the reinforcing cord of the belt edge reinforcing layer is increased as the winding density is higher. In a pneumatic radial tire in which a belt layer is disposed on the outer peripheral side of the carcass layer in the tread portion, the tire width direction of the edge of the end portion of the belt layer and between the innermost belt layer and the carcass layer the belt edge reinforcement layer having a width that extends from the inside to the outside in the tire width direction and circumferentially pneumatic radial tire having high gradually toward the rigidity of the belt edge reinforcement layer in the tire width direction outer side from the tire width direction inside. The pneumatic radial tire according to claim 6 , wherein the belt edge reinforcing layer is made of rubber having a dynamic elastic modulus E ′ at room temperature of 10 MPa to 70 MPa. The belt edge reinforcing layer is composed of a reinforcing cord spirally wound in a range of 0 ° to 15 ° with respect to the tire circumferential direction, and the winding density of the reinforcing cord is directed from the inner side in the tire width direction toward the outer side in the tire width direction. The pneumatic radial tire according to claim 6 , which is gradually increased. The pneumatic radial tire according to claim 8 , wherein the reinforcing cord of the belt edge reinforcing layer is covered with a rubber having a dynamic elastic modulus E 'at room temperature of 20 MPa or less. The pneumatic radial tire according to claim 8 or 9 , wherein the winding tension of the reinforcing cord is gradually increased from the inner side in the tire width direction toward the outer side in the tire width direction .