JP4582698B2 - Pneumatic radial tire - Google Patents

Description

  The present invention relates to a pneumatic radial tire (hereinafter, also simply referred to as “tire”), and more specifically, a pneumatic radial tire in which various tire performances such as high-speed durability are improved by improving a cap structure or a cap layer structure. About.

  In recent years, at least two angled steel belts are mainly used in the belt layer of pneumatic radial tires for passenger cars, and stability during running is ensured, especially in the belt layer peeling at high speed (especially at the belt layer end). In order to prevent the remarkable peeling) and improve durability, a cap layer made of nylon (polyamide) or the like is additionally used in some cases. Here, the cap is a belt reinforcing layer in which organic fiber cords arranged substantially parallel to the tire circumferential direction are embedded in rubber, and is disposed outside the belt in the radial direction over the entire width of the belt. The layer is a belt reinforcing layer in which organic fiber cords arranged substantially parallel to the tire circumferential direction are embedded in rubber, and the outer side in the tire radial direction of the belt layer at both ends The one arranged in

  At present, it is common to employ such a cap layer structure in order to improve the high-speed durability, and the cord material is mainly nylon which has low heat generation and low cost. However, further improvements are demanded with respect to reduction of road noise and flat spots, which are required characteristics of tires for recent OE (new car mounting), and the protruding property of the belt layer end at the time of the above-described high-speed running. . Here, the flat spot is the portion where the tire is heated and the carcass ply cord is extended and the vehicle stops running and then the tire cools down after a certain period of time. As a result of the cord being held in an extended state, it refers to a phenomenon in which vibration is generated when traveling is started again.

  As an improvement measure for the above problems, polyethylene naphthalate (PEN) and aramid are highly elastic compared to nylon for the cap layer and are effective in suppressing the protrusion of the belt layer end during running or reducing flat spots. Any material such as a composite material containing aramid (for example, an aramid / nylon hybrid) has been applied.

  In particular, as a technique for improving high-speed performance, for example, in Patent Document 1, a band layer composed of a plurality of band plies is arranged on the outer side in the tire radial direction of the belt layer, and this band layer is disposed outside the belt layer. A pneumatic radial tire is described which includes a high modulus band ply covering an end portion and a band ply disposed on the outer side in the tire radial direction and covering the entire width of the belt layer. Furthermore, in Patent Document 2, a belt reinforcing layer formed by spirally winding an organic fiber cord in the tire circumferential direction is provided on the tread side of both ends of the belt layer, and the material, elongation rate, and A pneumatic radial tire is described in which high-speed durability and high-frequency road noise are improved by prescribing the shrinkage rate to a predetermined value.

Furthermore, in Patent Document 3, for the purpose of improving tire characteristics such as high-speed durability and steering stability while reducing the tire weight, at least a breaker having a cord extending substantially in the tire circumferential direction is disclosed. Cover ply covering end, cord of cover ply shall be made of low heat shrinkage or non-heat shrink material, and selecting tire cover ply material, configuration or cord configuration for tire extension during tire manufacturing process Pneumatic tires are described which are guaranteed by
JP 2000-62412 A (Claims etc.) JP 2001-180220 A (Claims etc.) Japanese Patent No. 3145902 (Claims etc.)

  However, the conventional means for changing the material of the cap layer is the high cost of any material, and because there is little elongation during vulcanization, as a result of the tire after vulcanization The cord of the cap layer layer and the cord of the belt layer come into contact with each other, and as a result, peeling of the belt layer end portion may be caused.

  Accordingly, an object of the present invention is to prevent peeling of the belt layer end during high-speed running, to improve high-speed durability, to reduce road noise and flat spots, and to improve the belt layer end pushing performance. Further, it is to provide a pneumatic radial tire excellent in cost.

  As a result of intensive studies to solve the above problems, the present inventor changed the cord material in the cap structure or the cap layer structure between the tire center region and the shoulder region by applying a so-called core molding method. Thus, the inventors have found that it is possible to achieve both various tire performance and cost performance, and have completed the present invention.

That is, the pneumatic radial tire of the present invention is disposed on the outer periphery of the crown portion of the radial carcass from the inner layer side over the belt layer composed of at least one steel belt and over the entire width of the belt layer. In a pneumatic radial tire sequentially including a cap layer formed by rubberizing organic fiber cords arranged substantially in parallel,
The cap layer is molded by spirally attaching a ribbon-like strip on the outer surface of a rotating body having an outer surface shape having a diameter difference, and the material of the organic fiber cord of the cap layer is a tire center region and a shoulder region. And the organic fiber cord in the shoulder region is made of polyketone or a composite material containing polyketone.

Further, another pneumatic radial tire of the present invention is disposed on the outer periphery of the crown portion of the radial carcass from the inner layer side to a belt layer composed of at least one steel belt, over the entire width of the belt layer, and in the tire circumferential direction. A cap layer formed by rubber-drawing organic fiber cords arranged substantially in parallel with each other, and organic fiber cords arranged in both end regions of the belt layer and arranged substantially parallel to the tire circumferential direction In pneumatic radial tires that are sequentially provided with a layer layer formed by rubberizing
The cap layer and the layer layer are formed by affixing a ribbon-like strip spirally on the outer surface of a rotating body having an outer surface shape having a diameter difference, and the organic fiber cord constituting the cap layer and the layer layer is formed. The material is different between the tire center region and the shoulder region, and the organic fiber cord in the shoulder region is made of polyketone or a composite material containing polyketone.

  In the present invention, the organic fiber cord in the tire central region is preferably made of polyamide or polyethylene terephthalate.

  According to the present invention, the configuration described above eliminates peeling of the belt layer end during high-speed running, and is excellent in high-speed durability, while reducing road noise and flat spots, and the belt layer end protruding property. Improvements can be achieved, and furthermore, it has become possible to realize a pneumatic tire that is excellent in terms of cost.

Hereinafter, preferred embodiments of the present invention will be described in detail.
1 (a) and 1 (b) are partial sectional views showing examples of the pneumatic radial tire of the present invention. As shown in the figure, a pneumatic radial tire 10 according to the present invention includes a belt layer 2 composed of at least one layer, in the illustrated example, two layers of steel belts on the outer periphery of the crown portion of the radial carcass 1, and its full width. A cap structure (a in the figure) including a cap layer 3 formed by rubber-drawing organic fiber cords arranged over the above and arranged substantially parallel to the tire circumferential direction, or a belt A cap layer structure (layer (b) in the figure) comprising: a layer layer 4 formed by rubberizing organic fiber cords arranged in both end regions of the layer 2 and arranged substantially parallel to the tire circumferential direction It is a tire which has.

  In the present invention, the material of the organic fiber cord constituting the cap structure or the cap layer structure is different between the tire center region and the shoulder region. Accordingly, by applying appropriate materials to the tire central region and the shoulder region, various tire performances can be improved without using a large amount of high-cost materials. In the case of the cap layer structure, if the desired tire performance can be obtained, the material of the organic fiber cord may be different between the tire center region and the shoulder region only for the cap layer 3. The cap layer 3 and the layer layer 4 may be made of different materials of organic fiber cords in the tire central region and the shoulder region.

  The material of the organic fiber cord applied to each of the tire central region and the shoulder region may be used in combination as appropriate according to the desired tire performance, and is not particularly limited. Polyamide (nylon) or polyethylene terephthalate (PET) is applied to the fiber cord, and a composite material containing polyketone (PK) or PK is applied to the organic fiber cord in the shoulder region. Highly elastic PK or organic fiber cord made of PK-containing composite material is arranged only in the tire shoulder region, and nylon or PET is applied to the other tire central region, thereby improving various tire performance and cost performance. It is possible to achieve both.

  Since PK is expensive, it is preferable that the organic fiber cord made of PK or a composite material containing PK is applied in such a manner that it covers at least the end of the belt layer with a minimum amount from the viewpoint of cost. Specifically, for example, it can be applied with a width of about 10 to 25 mm. PK also has the property of being superior in heat-resistant adhesion as compared to the above-mentioned PEN and aramid, so that a significant improvement effect can be obtained in terms of high-speed durability compared to the case where these materials are applied. There is an advantage. Examples of the composite material containing PK include a PK / nylon hybrid material.

  The cap structure or the cap layer structure in the tire of the present invention is formed by applying a so-called core molding technique in the molding process. That is, in the present invention, in addition to the cord material being divided and arranged in the same tire, the high elastic cord is less stretched during vulcanization elongation and the cap or cap layer and the belt layer 2 In order to eliminate cord contact, it is necessary to adopt core molding. Here, the core molding is a technique for performing a molding process by affixing a ribbon-like strip spirally on the outer surface of a rotating body having an outer surface shape having a diameter difference, and approximated to the inner surface shape of a product tire. By molding using a rotating body having an outer surface shape, the diameter expansion deformation during vulcanization can be made as small as possible, and the tire quality such as uniformity can be stabilized (for example, JP-A 2003-334867, JP-A 2004-17621, etc.).

  In the tire of the present invention, as long as the above-described conditions are satisfied with respect to the cap or the cap layer structure, the details of the tire structure and the material of other members can be appropriately applied as conventionally known. There is no particular limitation. Moreover, there is no restriction | limiting in particular also about the twist number and fineness of each organic fiber cord used for the said cap layer 3, the layer layer 4, etc., It is possible to select suitably according to desired tire performance.

Hereinafter, the present invention will be specifically described with reference to examples.
In accordance with the conditions shown in Table 1 below, a pneumatic radial tire having a cap layer structure shown in FIG. 1B was manufactured at a tire size of 195 / 65R14. As the molding method of the cap layer and the layer layer, two types of the conventional molding method for molding the entire tire by separately preparing and laminating each member of the tire and the above-described core molding method were used. . For each of the obtained test tires, the following various tire performances were evaluated under the conditions of tire internal pressure: 200 kPa and rim size: 6J-14. The results are also shown in Table 1 below.

* 1) High speed durability Each test tire was run at 150 km / h for 30 minutes, and if there was no failure, the speed was increased by 6 km / h, and the test was terminated when the failure occurred. The results were calculated so that the failure occurrence rate of Comparative Example 1 was an index of 100 and the index was 100 or more in the direction in which the durability limit speed was high (good).

* 2) Belt layer end protrusion amount The amount of protrusion (high-speed deformation) in the shoulder region when each test tire was run at 150 km / h was measured. The result was calculated so that the amount of protrusion in Comparative Example 1 was 100, and the index was 100 or more in the (good) direction in which the amount of protrusion was reduced.

* 3) Cap layer use cost per tire For each test tire, the tire size: 195 / 65R14 was used as a model size, and the use cost related to the cap layer structure per tire was estimated. The result was calculated so that the cost of Comparative Example 1 was 100, and the index was 100 or more in the direction of low cost (good).

* 4) Road noise test Each prototype tire is mounted on a sedan type passenger car with a displacement of 2000 cc, and all four wheels are on board. Two people ride on the road noise evaluation road at a speed of 60 km / h. The total sound pressure (decibel) at frequencies of 100 to 500 Hz and 300 to 500 Hz was measured with a sound collecting microphone attached to the center side of the backrest portion of the driver's seat, and road noise was evaluated from the measured values. The results were calculated so that the road noise of Comparative Example 1 was 100, and the index was 100 or more in the (good) direction in which road noise was reduced.

* 5) Flat spot test The flat spot property is the deformation of a tire after each test tire is mounted on an actual vehicle and allowed to run for a certain period of time, and then the tire is fully heated and left to cool completely. Were measured and evaluated with changes in roundness. That is, the roundness before and after the load was measured, and the difference was detected as a flat spot amount. The result was calculated so that the flat spot amount of Comparative Example 1 was an index of 100, and the index was 100 or more in the (good) direction in which the flat spot was reduced.

* 6) Cap Layer / Belt Interlayer Gauge For each test tire, the tire size: 195 / 65R14 was used as a model size, and the distance from the belt layer end to the shortest cap layer was measured. The results were calculated so that the interlayer distance of Comparative Example 1 was 100, and the index was 100 or more in the (good) direction in which the interlayer distance was large.

  As shown in Table 1 above, in Examples 1 to 3 in which the material of the organic fiber cord of the cap layer and the layer layer is changed between the tire center region and the shoulder region, and the core molding method is used as the molding method. Good evaluation was obtained for all tire performances without incurring a significant cost increase as in Comparative Example 2. On the other hand, the cap layer / belt interlayer gauge is narrow in Comparative Examples 3 and 4 in which the conventional method is used as the molding method only by changing the material of the organic fiber cord of the cap layer and the layer layer. It can be seen that there is a high possibility that the end of the belt will be peeled off due to the contact.

(A), (b) is a fragmentary sectional view showing a suitable example of a pneumatic radial tire of the present invention.

Explanation of symbols

1 radial carcass 2 belt layer 3 cap layer 4 layer layer 10 pneumatic radial tire

Claims (3)

An organic fiber cord arranged on the outer periphery of the crown portion of the radial carcass from the inner layer side over at least one steel belt over the entire width of the belt layer and arranged substantially parallel to the tire circumferential direction. In a pneumatic radial tire sequentially including a cap layer formed by rubberizing,
The cap layer is molded by spirally attaching a ribbon-like strip on the outer surface of a rotating body having an outer surface shape having a diameter difference, and the material of the organic fiber cord of the cap layer is a tire center region and a shoulder region. different Ri, and between, the organic fiber cord in the shoulder region, the pneumatic radial tire characterized by a composite material containing polyketones or polyketone. An organic fiber cord arranged on the outer periphery of the crown portion of the radial carcass from the inner layer side over at least one steel belt over the entire width of the belt layer and arranged substantially parallel to the tire circumferential direction. And a layer layer formed by rubberizing organic fiber cords disposed in both end regions of the belt layer and arranged substantially parallel to the tire circumferential direction. In entering radial tires,
The cap layer and the layer layer, on the outer surface of the rotating body having an outer surface shape with a diameter difference, is molded by pasting the ribbon-like strip helically, organic fiber cords constituting the 該Ki cap layer and the layer layer material backlash Unlike in the ear central region and the shoulder region, and the said organic fiber cord in the shoulder region, the pneumatic radial tire characterized by a composite material containing polyketones or polyketone. The pneumatic radial tire of Na Ru claim 1 or 2, wherein said organic fiber cord is a polyamide or polyethylene terephthalate in the tire center region.

Images