JP2006327305A - Pneumatic radial tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic radial tire devised capable of preventing breakage in which distortion generated on an end part in the cross direction of a belt layer in travelling influences upon a carcass layer and providing more excellent tire durability. <P>SOLUTION: This pneumatic radial tire is constituted of the carcass layer 2 installed between a pair of left and right bead parts 3 and a belt layer 5 arranged on the outer peripheral side on a tread part 4 of the carcass layer 2, wherein a rubber-covered sheet 6 of plain weave fabric is arranged between the end part in the cross direction of the belt layer 5 and the carcass layer 2 and angles made by warp 8 and weft 9 of the plain weave fabric 7 relative to the tire peripheral direction are respectively 30° to 60°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pneumatic radial tire, and more particularly to a pneumatic radial tire in which the durability of a carcass layer is improved to improve the tire durability.

  When a pneumatic radial tire is filled with its internal pressure, the carcass layer tends to be arcuate and the cross-sectional shape is rounded outward in the radial direction. For this reason, the width direction edge part (belt layer edge part) of the belt layer arrange | positioned on the outer periphery of a carcass layer generate | occur | produces the force which leaves | separates from a carcass layer.

  Conventionally, in order to prevent this phenomenon, a rubber sheet is inserted between the carcass layer and the belt layer end. (For example, refer to Patent Document 1).

However, in the insertion of the rubber sheet, the strain generated at the end in the width direction of the belt layer easily propagates to the carcass layer, and it cannot be said that the tire durability is necessarily satisfactory, and a measure for obtaining higher durability is taken. It has been requested.
JP 2001-121916 A

  An object of the present invention is to provide a pneumatic radial tire that prevents damage caused to the carcass layer by distortion generated at the end in the width direction of the belt layer during traveling, and that can provide further excellent tire durability. is there.

  The pneumatic radial tire of the present invention that achieves the above object is a pneumatic radial tire in which a carcass layer is mounted between a pair of left and right bead portions, and a belt layer is disposed on the outer peripheral side of the tread portion of the carcass layer. Air in which a plain fabric rubber-coated sheet is disposed between the widthwise end of the belt layer and the carcass layer, and the angles between the warp and the weft of the plain fabric and the tire circumferential direction are 30 ° to 60 °, respectively. This is a radial tire.

  The pneumatic radial tire of the present invention is a carcass layer having a strain generated at the end portion in the width direction of the belt layer by disposing a plain fabric rubber-coated sheet between the end portion in the width direction of the belt layer and the carcass layer. Since the propagation to the side is efficiently blocked, the tire durability can be improved. Further, by setting the angle between the warp and the weft of the plain woven fabric to the tire circumferential direction to be 30 ° to 60 °, the tire can be easily stretched in the tire circumferential direction to reduce the binding force, and the effect of blocking the generated strain can be reduced. It can be manufactured uniformly.

  The present invention is described in detail below.

  FIG. 1 shows an example of a meridional direction sectional view of a pneumatic radial tire of the present invention.

  In FIG. 1, a carcass layer 2 is mounted between a pair of left and right bead portions 3, and an end portion of the carcass layer 2 is locked around the bead portion 3 so as to be folded back from the inside of the tire to the outside. In the tread portion 4, a belt layer 5 made of a steel cord is disposed outside the carcass layer 2 over the circumference of the tire. A plurality of belt layers 5 are arranged so that steel cords cross each other.

    The pneumatic radial tire of the present invention has a plain woven rubber-coated sheet 6 made of warp and weft between the width direction end of the belt layer 5 (hereinafter also referred to as belt layer end) and the carcass layer. Is to be placed.

  This plain woven rubber-coated sheet 6 prevents warp and weft from passing through to the carcass layer 2 in the middle of the distortion of the belt layer end, thereby preventing blowout to the carcass layer 2 and improving durability. It is.

  FIG. 2 is an explanatory view showing an example of a plain woven fabric used for the rubber-coated sheet 6 of the plain woven fabric of the present invention.

  In FIG. 2, a plain fabric 7 is a biaxial plain fabric composed of warp yarns 8 and weft yarns 9, and the warp yarns 8 and the weft yarns 9 are woven in a straight line. The warp yarns 8 and the weft yarns 9 of the plain woven fabric are arranged so that the angle θ formed with the tire circumferential direction is in the range of 30 ° to 60 °, preferably 35 ° to 55 °. By setting the angle θ between the warp yarns 8 and the weft yarns 9 of the plain woven fabric and the tire circumferential direction within the above range, the plain woven fabric 7 can easily extend in the tire circumferential direction to reduce the restraining force, and the tire can be manufactured uniformly. it can. That is, when the angle θ formed by the plain woven warp 8 with respect to the tire circumferential direction is less than 30 °, the range in which the angle can be changed with respect to the tension in the tire circumferential direction is small, and thus the warp 8 has a binding force in the tire circumferential direction. It will be. If it does so, there exists a possibility of inhibiting a uniform diameter expansion in the inflation process at the time of tire manufacture. Similarly, when the angle formed by the warp 8 of the plain woven fabric with respect to the tire circumferential direction exceeds 60 °, the angle formed by the weft 9 with respect to the tire circumferential direction becomes less than 30 °, and the tire may not be manufactured uniformly. .

  The plain woven rubber coated sheet of the present invention preferably has a width of 20 to 60 mm, more preferably 30 to 55 mm. By setting the width of the plain woven rubber coated sheet to 20 mm or more, the effect of blocking the strain propagating from the belt layer end portion can be sufficiently obtained. Is preferably 60 mm or less.

  In the present invention, the plain woven rubber-coated sheet is disposed so that the end of the belt layer straddles the inner side and the outer side in the width direction, and is preferably 10 mm or more, more preferably 15 mm or more, in the width direction and outside from the belt layer end. It may be arranged to extend. By disposing the plain woven rubber covering sheet so as to straddle the belt layer end and extend outward in the width direction, propagation of strain at the belt layer end can be blocked.

  In the plain fabric 7 used in the present invention, the warp interval t and the weft interval t 'are preferably 8 mm or less, more preferably 5 mm or less, and further preferably 1 to 4 mm. By setting the warp interval t and the weft interval t ′ within the above ranges, it is possible to effectively prevent the distortion from the belt layer end from propagating to the carcass layer. The lower limit of the warp interval t and the weft interval t 'is preferably 0.5 mm. By setting 0.5 mm as the lower limit, it is possible to ensure the permeability of the coated rubber to the plain woven fabric and to improve the strain propagation blocking effect.

  In the plain fabric 7 used in the present invention, the warp 8 and the weft 9 are preferably organic fiber cords. In the case of steel cord or inorganic fiber cord, the end of the end has an acute angle, and the plain fabric itself may become a new stress concentration source. Such an organic fiber cord is not particularly limited, but preferably nylon 6 fiber, nylon 66 fiber, polyvinyl alcohol fiber, rayon fiber, acrylic fiber, polyketone fiber and the like. By using such an organic fiber cord, it is possible to absorb the strain propagating from the end portion of the belt layer and to block the propagation to the carcass layer side.

  The positive fineness of the warp and weft constituting the plain fabric is preferably in the range of 400 to 4500 dtex, more preferably 800 to 4000 dtex. By making the positive fineness of the warp and the weft to be 400 dtex or more, the propagation of the strain of the plain woven fabric is more reliably blocked. On the other hand, when it exceeds 4500 dtex, the effect of blocking the propagation of strain is almost saturated, but rather the disadvantage of increasing the thickness of the plain fabric is brought about.

  The positive fineness is a value measured according to JIS-L1017.

  By inserting such a plain woven rubber-coated sheet between the end of the belt layer and the carcass layer, it is possible to prevent the strain generated at the end of the belt layer from propagating to the carcass layer, thereby protecting the carcass layer. And durability can be improved.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, the scope of the present invention is not limited to these Examples.

[Evaluation of tire durability]
The evaluation tire (tire size 265 / 70R16) was rim assembled to a rim (rim size 16 × 7JJ), and then subjected to dry heat deterioration at an oxygen pressure of 350 kPa and a temperature of 70 ° C. for 14 days. After dry heat deterioration, the filled oxygen is replaced with air, the air pressure is set to 170 kPa, and the load (load = 11.0 kN ± 2.5 kPa) and the slip angle (slip angle = 0 ° ± 3 °) are changed to sine wave (0 .03 Hz), and a running test was performed at a speed of 60 km / hour.

  The running test described above was continued until the tire broke down, and the durability of the evaluated tire was evaluated with an index with the running distance of the following conventional example as 100.

Conventional Example A rubber sheet having a width of 40 mm was inserted between the end of the belt layer and the carcass layer, and an evaluation tire was produced by a normal production method.

  The tire uniformity of the obtained evaluation tire was evaluated based on JIS-D4233, and this result was regarded as a conventional example level.

  The durability of the obtained evaluation tire was measured by the above-mentioned method, and the tire running index was defined as 100 as the tire durability index.

Example 1
An angle between a plain woven rubber-coated sheet using a nylon 66 fiber cord with a positive fineness of 1400 dtex for warp and weft and sandwiching a plain woven fabric with a warp spacing and a weft spacing of 8.0 mm between the plain woven warp and the tire circumferential direction. However, the tires were arranged so as to be 45 ° to produce evaluation tires.

  It was confirmed that the obtained evaluation tire had a tire uniformity based on JIS-D4233 at a conventional level and was manufactured uniformly.

  The tire durability of the obtained evaluation tire was evaluated by the above method. The evaluation results are shown in Table 1.

Examples 2-4
Evaluation tires were produced in the same manner as in Example 1 except that the structure of the plain fabric used for the rubber-coated sheet of the plain fabric was changed to the warp angle and cord interval as shown in Table 1.

  Each of the obtained evaluation tires was confirmed to have a uniform tire uniformity based on JIS-D4233, which was a conventional example.

  The durability of each of the obtained evaluation tires was evaluated, and the results are shown in Table 1.

Comparative Example 1
An evaluation tire was produced in the same manner as in Example 1 except that the structure of the plain woven fabric used for the plain woven rubber coated sheet was changed to the warp angle and the cord interval as shown in Table 1.

  As a result of evaluating the tire uniformity based on JIS-D4233, it was confirmed that the radial tire variation of the obtained evaluation tire is larger than the level of the conventional example, and there is a problem in uniformity in the manufacturing process. Was recognized.

  The durability of the obtained evaluation tire was evaluated, and the results are shown in Table 1.

  As is apparent from Table 1, the pneumatic radial tires (Examples 1 to 4) using the plain woven rubber-coated sheet of the present invention have the same level of uniformity at the time of manufacturing the tire and are more durable than the conventional example. It was recognized that the sex was improved. Moreover, it was recognized that Example 3 and 4 which narrowed the cord space | interval in a plain fabric was excellent in tire durability compared with Example 1.

  In contrast, in Comparative Example 1, it was confirmed that the uniformity at the time of tire manufacture was reduced because the plain woven rubber-coated sheet was disposed so that the warp angle was 20 °. For this reason, the tire durability was inferior to that of the conventional example using a rubber sheet.

It is explanatory drawing which shows an example of meridian direction sectional drawing of the pneumatic radial tire of this invention. It is explanatory drawing which shows an example of the plain fabric used for the rubber-coated sheet | seat of the plain fabric of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pneumatic radial tire 2 Carcass layer 3 Bead part 4 Tread part 5 Belt layer 6 Rubber covering sheet of plain fabric 7 Plain fabric 8 Warp 9 Weft

Claims (5)

  In a pneumatic radial tire in which a carcass layer is mounted between a pair of left and right bead portions, and a belt layer is disposed on the outer peripheral side of the tread portion of the carcass layer, between the widthwise end of the belt layer and the carcass layer A pneumatic radial tire in which a rubber woven sheet of a plain woven fabric is arranged, and the angle between the warp and weft of the plain woven fabric and the tire circumferential direction is 30 ° to 60 °, respectively.   The pneumatic radial tire according to claim 1, wherein a warp interval and a weft interval of the plain fabric are 5 mm or less.   The pneumatic radial tire according to claim 1 or 2, wherein the normal fineness of the warp and weft of the plain fabric is 400 to 4500 dtex.   The pneumatic radial tire according to any one of claims 1 to 3, wherein the warp and the weft of the plain fabric are organic fiber cords. The pneumatic radial tire according to any one of claims 1 to 4, wherein the organic fiber cord is made of at least one of nylon 6 fiber, nylon 66 fiber, polyvinyl alcohol fiber, rayon fiber, acrylic fiber, and polyketone fiber.

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