JP2008179178A - Pneumatic radial tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic radial tire efficiently suppressing vibration or noise generated in rolling of the tire. <P>SOLUTION: The pneumatic radial tire 10 has a carcass layer extending toroidally between a pair of bead cores, and a belt layer outside in radial direction of a crown part of the carcass layer. The belt layer is composed of a first belt layer 16A where a plurality of belt layer units 26 having a constant cord spacing are arranged and a second belt layer 16B of the outside in the tire radial direction of the first belt layer 26. The cord spacing of the second belt layer 16B is wider than that of the first belt layer 16A. The spacing of the belt layer units 26 adjacent to the tire circumferential direction U is made to be the one layer structure belt part composed of only the second belt layer 16B. Therefore, belt rigidity is a random distribution on the circumference. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pneumatic radial tire in which vibration and abnormal noise during tire rolling are reduced.

  In conventional pneumatic radial tires, high-order RFV components (for example, the 7th to 8th components) have a peak due to joint variations in the tire and pitch variations of the tread pattern, and vibration and noise during tire rolling. May occur.

  In order to suppress this vibration and noise, Patent Document 1 discloses a measure for intentionally increasing the number of belt ply joints.

However, not only the number of joints can be increased, but if a tire structure with other effective measures can be provided, vibration and noise can be efficiently suppressed.
JP 2005-186325 A

  In view of the above facts, an object of the present invention is to provide a pneumatic radial tire that efficiently suppresses vibrations and noise generated during tire rolling.

  The inventor has paid attention to the fact that vibrations and abnormal noise may occur due to force fluctuations (order component of RFV) on the circumference due to the number of divisions of the tire manufacturing jig. Therefore, intensive studies were made to eliminate this cause, and experiments were repeated to complete the present invention.

  According to a first aspect of the present invention, there is provided an air having at least one carcass layer extending in a toroidal shape between a pair of bead cores and at least two belt layers radially outward of a crown portion of the carcass layer. In the contained radial tire, the belt layer includes a plurality of cord spacing constant portions having a constant cord spacing, and a plurality of cord spacing wide portions adjacent to the cord spacing constant portion and having a cord spacing wider than the cord spacing constant portion. And a plurality of the wide code-spacing portions have different perimeters on the circumference.

  Thus, in the first aspect of the invention, the circumferential lengths of the plurality of wide code spacing portions vary on the circumference and are not constant. As a result, the belt rigidity has a random distribution on the circumference, and a peak can not be generated in a specific higher-order component of RFV. Therefore, vibration and noise generated during tire rolling can be efficiently suppressed by simply changing the configuration of the belt layer.

  According to a second aspect of the present invention, the circumferences of the plurality of constant code interval portions are the same.

  Thereby, in a manufacturing process, since the member to prepare can be made the same, the fall of production efficiency can be decreased.

  The invention according to claim 3 is characterized in that the number of the wide code interval portions is in the range of 20-50.

  This is because if the number of wide portions of the cord interval is less than 20, the peak of the high-order component of RFV cannot be broken, and if it exceeds 50, the tire manufacturing process becomes complicated.

  According to the third aspect of the present invention, it is possible to prevent the generation of vibrations and abnormal noises by breaking the peak of higher-order components of RFV without complicating the tire manufacturing process.

  According to a fourth aspect of the present invention, the belt layer is composed of a rubber coating layer of two steel cords, and an average cord interval of each layer of the belt layer is different from each other.

  Thereby, the belt rigidity can be made different between the two rubber coating layers constituting the belt layer, and the occurrence of vibration and noise during tire rolling can be further suppressed.

  Since the present invention has the above configuration, the following effects can be obtained.

  According to the first aspect of the present invention, vibration and noise generated during tire rolling can be efficiently suppressed by simply changing the configuration of the belt layer.

  According to invention of Claim 2, since the member to prepare can be made the same in a manufacturing process, the fall of production efficiency can be decreased.

  According to the third aspect of the present invention, it is possible to prevent the generation of vibrations and noises by breaking the peak of the high-order component of RFV without complicating the tire manufacturing process.

  According to invention of Claim 4, generation | occurrence | production of the vibration and abnormal noise at the time of tire rolling can further be suppressed.

  Hereinafter, embodiments will be described and embodiments of the present invention will be described. As shown in FIG. 1, a pneumatic radial tire 10 according to an embodiment of the present invention includes a single carcass layer 14 extending in a toroidal shape between a pair of bead cores 11 and a diameter of a crown portion 14 </ b> C of the carcass layer 14. A belt layer 16 is provided on the outer side in the direction, and a tread portion 18 is provided on the outer side in the radial direction of the belt layer 16. The pneumatic radial tire 10 includes a sidewall portion 20 between the pair of bead portions 12 having the bead core 11 and the tread portion 18.

  In the tread portion 18, a plurality of circumferential grooves (main grooves) 22 along the circumferential direction and a plurality of lateral grooves intersecting with the circumferential direction are formed on both sides of the tire equatorial plane CL. The end of each lateral groove communicates with the circumferential groove 22 or extends so as to be able to drain the tire width direction outside beyond the tread end. Here, the tread end means that a pneumatic tire is mounted on a standard rim specified in JATMA YEAR BOOK (2006 edition, Japan Automobile Tire Association Standard), and the maximum load in the applicable size and ply rating in JATMA YEAR BOOK. Fills 100% of the air pressure (maximum air pressure) corresponding to the capacity (internal pressure-load capacity correspondence table) as the internal pressure, and indicates the outermost ground contact portion in the tire width direction when the maximum load capacity is applied. In addition, when TRA standard and ETRTO standard are applied in a use place or a manufacturing place, it follows each standard.

  The belt layer 16 includes a first belt layer 16A that is radially outward of the carcass layer 14 and a second belt layer 16B that is radially outward of the first belt layer 16A. Each of the first belt layer 16A and the second belt layer 16B is made of a steel cord rubber coating layer. In the present embodiment, the average cord interval of the first belt layer 16A is narrower than the average cord interval of the second belt layer 16B.

  As shown in FIG. 2, the first belt layer 16 </ b> A is composed of a number of parallel layer-shaped belt layer units 26 with a constant cord interval. Each belt layer unit 26 is arranged along the tire circumferential direction U, and the short side 26S of each belt layer unit 26 is directed in the tire circumferential direction U. In the present embodiment, the circumferential length (tire circumferential length) of each belt layer unit 26 is the same circumferential length La. La is relatively narrow. Further, the arrangement positions of the belt layer units 26 in the circumferential direction are set so that the interval Lb between the belt layer units 26 adjacent in the circumferential direction is not constant, that is, Lb varies. Lb is narrower than La.

  On the other hand, the cord interval of the second belt layer 16B is wider than that of the first belt layer 16A. The cord intervals of the second belt layer 16B are made uniform.

  With this configuration, as shown in FIG. 3, the belt layer 16 has a two-layer structure in the portion where the first belt layer 16A is disposed, and the second belt layer 16B in a portion where the first belt layer 16A is not disposed. It is only a one-layer structure belt portion 30. The single-layer structure belt portion 30 is disposed adjacent to the belt layer unit 26.

  In the present embodiment, the number of single-layer structure belt portions 30 is in the range of 20-50. As a result, when the order analysis is performed on the array for one round of the code interval Lb, the specific order does not have a peak.

  As described above, in the present embodiment, the one-layer structure belt portion 30 having only the second belt layer 16B having a cord interval different from the belt layer unit 26 is provided between the belt layer units 26 having a constant cord interval. Has been placed. The circumferential length Lb of each single-layer structure belt portion 30 is not constant but varies, and the width of the so-called open joint portion varies. Thereby, the distribution of the belt rigidity on the circumference can be made random, and a peak can not be generated in a specific high-order component of RFV. Therefore, vibrations and noises generated during tire rolling can be efficiently suppressed by simply changing the configuration of the belt layer 16 as compared with the conventional case.

  Further, the circumference of each belt layer unit 26 is constant at La. Thereby, the fall of production efficiency can be decreased.

  Further, the number of the single-layer structure belt portions 30 is in the range of 20 to 50, and when the order analysis is performed on the arrangement of one turn of the cord interval Lb, there is no peak in a specific order. . Thereby, generation | occurrence | production of a peculiar vibration and unusual noise can be prevented, and it is avoided that manufacture of a tire becomes complicated.

  Further, the belt layer 16 is composed of a rubber coating layer of two steel cords, and the average cord intervals of the first belt layer 16A and the second belt layer 16B are different from each other. Thereby, in addition to the fluctuation of the so-called open joint width, it is possible to add a factor of making the belt rigidity different between the first belt layer 16A and the second belt layer 16B.

<Test example>
In order to confirm the effect of the present invention, the present inventor made an example of the pneumatic radial tire 10 of the above embodiment (hereinafter referred to as an example tire) and an example of a conventional pneumatic radial tire (hereinafter referred to as a conventional example). And tires were mounted on passenger cars, and noise resistance and vibration resistance were evaluated by running the vehicle.

  In this test example, for any tire, the steel cord constituting the belt layer 16 has a wire diameter of 0.23 mm and a 1 × 5 structure, and is provided with a cap layer (1400 dtex / 2 nylon). Moreover, in any tire, the tire size is PSR 185 / 65R15 88H.

  In the tire of the example, the length La in the tire circumferential direction of the belt layer unit having a constant cord interval was 50 mm, and the number of belt layer units was 30. Further, the distribution of the circumferential length Lb of the single-layer structure belt portion 30 was set with reference to the pitch variation of the pattern.

  In the conventional tire, the number of steel cords to be driven was 36/5 cm, and the cord intervals were uniform. Accordingly, in the belt layer composed of two layers, each belt treat is arranged at a constant interval in the circumferential direction.

  In this test example, all the tires were assembled in a regular rim and then mounted on a passenger car to obtain a regular internal pressure. Here, “regular rim” refers to the standard rim in the applicable size specified in the 2006 YEAR BOOK issued by JATMA, and “regular internal pressure” is defined in the 2006 YEAR BOOK issued by JATMA. It refers to the air pressure for the maximum load in the applicable size and ply rating. When the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards are followed.

For each tire, one occupant (only one driver) travels on the road surface for road noise evaluation at 50 km / h, and the sound pressure is measured as a noise level with a microphone attached to the driver's seat ear. The noise resistance was evaluated. The evaluation results are shown in Table 1.

  In this test example, the sound pressure measured with the tire of the conventional example was used as a reference value, and the relative sound pressure with respect to the reference value was obtained for the tire of the example. Table 1 shows that the sound pressure measured with the tire of the example was 4.0 db lower than the reference value.

  The sound pressure shown in Table 1 indicates that the lower the numerical value, the smaller the noise and the better the noise resistance. As can be seen from Table 1, the tires of the examples were superior in noise resistance compared to the conventional tires.

  Moreover, in this test example, the vibration level was evaluated by the occupant's feeling on the same road surface. The evaluation results are also shown in Table 1. As can be seen from Table 1, the tires of the examples were superior in vibration resistance as compared to the conventional tires.

  The embodiments of the present invention have been described with reference to the embodiments. However, the above embodiments are merely examples, and various modifications can be made without departing from the scope of the invention. Needless to say, the scope of rights of the present invention is not limited to the above embodiment.

It is a tire radial direction sectional view of a pneumatic radial tire concerning one embodiment of the present invention. It is a top view showing the 1st belt layer of the pneumatic radial tire concerning one embodiment of the present invention. It is a typical tire radial direction fragmentary sectional view showing that the 1 layer structure belt part is arranged by the pneumatic radial tire concerning one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pneumatic radial tire 11 Bead core 14 Carcass layer 14C Crown part 16 Belt layer 18 Tread part 26 Belt layer unit (Cord space constant part)
30 1-layer structure belt part (part with wide cord spacing)

Claims (4)

In a pneumatic radial tire having at least one carcass layer extending in a toroidal shape between a pair of bead cores, and a belt layer composed of at least two layers on the radially outer side of the crown portion of the carcass layer,
The belt layer includes a plurality of cord interval constant portions in which the cord interval is constant,
A plurality of code interval wide portions adjacent to the code interval constant portion and having a code interval wider than the code interval constant portion;
On the circumference,
A pneumatic radial tire characterized in that the circumferential lengths of the plurality of wide code gap portions vary on the circumference.   The pneumatic radial tire according to claim 1, wherein the circumferential lengths of the plurality of portions having a constant cord interval are the same.   The pneumatic radial tire according to claim 1 or 2, wherein the number of the wide code gap portions is in a range of 20 to 50. The belt layer consists of two steel cord rubber coating layers,
The pneumatic radial tire according to any one of claims 1 to 3, wherein an average cord interval of each belt layer is different from each other.

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