JP2006188147A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of being constructed light in its belt layers and bead part while durability of the bead part is maintained and serving for heavy load by reducing the rolling resistance. <P>SOLUTION: The pneumatic tire has three belt layers where the folded-back end as one end of a carcass layer in its folded-back part is located inside in the tire radial direction more than the wire chafer folded-back end as one end of a wire chafer in its folded-back part, and cords constituting the wire chafer located outside in the tire radial direction more than the folded-back end and outside in the tire width direction are inclined 0-45° to the tire circumferential direction, having a diameter of 0.7-1.5 mm and a spacing between cords of 0.7-2.0 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire having a wire chafer in which a plurality of cords are covered with rubber on the outside of a carcass layer that is folded along a bead core.

  Conventionally, in order to use a pneumatic tire for heavy loads, a wire chafer in which a steel cord is covered with rubber is disposed outside a carcass layer folded back along a bead core (for example, Patent Document 1). Heavy duty pneumatic tires apply a greater load than tires for passenger cars and place a heavy burden on the bead part. By providing the wire chafer as described above, the durability of the bead part is improved. ing.

  In addition to the wire chafer, the heavy load pneumatic tire is provided with four belt layers in order to increase the rigidity of the belt portion (for example, Patent Document 2).

By using the above method, a pneumatic tire can be used for heavy loads.
Japanese Patent Laid-Open No. 7-164837 JP 61-44006 A

  However, since the weight is increased by arranging the wire chafer in the bead part, it was desired to develop a pneumatic tire that can reduce the weight in the bead part while maintaining the durability of the bead part. .

  Further, as described above, the provision of four belt layers has a problem that the belt layer also increases in weight.

  However, if the number of belt layers is reduced in order to reduce the weight in the belt layer, the rigidity of the belt layer is reduced, so that the deformation of the belt layer is increased, which may deteriorate the rolling resistance.

  In view of the above problems, the present invention is a pneumatic tire that can be used for heavy loads by reducing the rolling resistance while reducing the weight of the belt layer and the bead part while maintaining the durability in the bead part. It is an issue to provide.

  In order to solve the above-mentioned problem, a first feature of the present invention is a pneumatic tire having a wire chafer in which a plurality of cords are covered with rubber on the outside of a carcass layer folded along a bead core. A first belt layer in which a plurality of first cords arranged with an inclination of 10 to 25 ° with respect to the equator line are covered with rubber, and an inclination of 10 to 25 ° with respect to the tire equator line in a direction different from the first cord A plurality of second cords arranged in the manner described above are covered with rubber, and arranged at an angle of 45 to 90 ° with respect to the tire equator line, with the second belt layer arranged on the outer side in the tire radial direction from the first belt layer A plurality of third cords covered with rubber and having a third belt layer disposed on the outer side in the tire radial direction from the second belt layer, and a folded end that is an end portion of a folded portion of the carcass layer, Wire chafer The cords constituting the wire chafer located on the inner side in the tire radial direction from the folded end of the wire chafer which is the end of the turned-up portion and on the outer side in the tire radial direction and the outer side in the tire width direction from the turned-up end are The pneumatic tire is characterized in that it is inclined by 0 to 45 ° with respect to the diameter, the diameter is 0.7 to 1.5 mm, and the distance between the cords is 0.7 to 2.0 mm. It is a summary.

  According to such a feature, in the pneumatic tire used for heavy loads, the pneumatic tire according to the present invention has three belt layers as compared with the belt layer that is normally laminated, so that Weight reduction can be achieved.

  Further, the cost can be reduced by making the belt layer, which has conventionally been used four layers, into three layers.

  Also, three layers of the first belt layer, the second belt layer, and the third belt layer are arranged from the inner side to the outer side in the tire radial direction, and the angle of the first cord constituting the first belt layer is relative to the tire equator line. The angle of the second cord constituting the second belt layer is 10 to 25 ° with respect to the tire equator line in the direction opposite to the first cord, and constitutes the third belt layer. Since the angle of the third cord is 45 to 90 ° with respect to the tire equator line, when the load is applied by laminating the first belt layer and the second belt layer, the two layers become tire widths. Since the third belt layer and the carcass layer having the cords arranged substantially in the tire width direction suppress the movement to shrink in the direction, durability in the belt layer can also be improved.

  Further, the folded end that is the end portion of the folded portion of the carcass layer is inside the tire radial direction from the wire chafer folded end that is the end portion of the folded portion of the wire chafer, and the outer side in the tire radial direction from the folded end and The cord constituting the wire chafer located on the outer side in the tire width direction is inclined by 0 to 45 ° with respect to the tire circumferential direction, has a diameter of 0.7 to 1.5 mm, and the distance between the cord and the cord is Since it is 0.7 to 2.0 mm, it is possible to follow the wire chafer cord with a crack that has occurred on the tire surface side and has occurred from the end of the carcass layer, which is a conventional failure factor. The durability can be improved. Further, by increasing the durability in the bead portion, it is possible to reduce the weight while securing the same durability as the current state by deleting the excess rubber.

  Furthermore, since the carcass layer in the bead portion is arranged 2 to 3 mm outside in the tire width direction due to the structure of the pneumatic tire as described above, when a load is applied to the tire and the tire is bent, it is more than conventional. Since the bead portion side is easily deformed, the force for deforming the belt layer is reduced, the loss in the belt layer is reduced, and the volume causing the loss of the bead portion is also reduced. % Can be reduced.

  According to the present invention, it is possible to provide a pneumatic tire that can be used for heavy loads by reducing the rolling resistance while reducing the weight of the belt layer and the bead part while maintaining the durability in the bead part. .

  Below, the pneumatic tire 1 which concerns on this embodiment is demonstrated.

  FIG. 1 is a cross-sectional view showing a tire body 1 in the present embodiment.

  The tire body 1 includes a pair of bead portions 2, a pair of side portions 3, a carcass layer 4, a belt layer 5, a tread portion 6, and a pair of wire chafers 7. It is fixed.

  A pair of bead portions 2 are provided, which are ring-shaped and are reinforcing materials for fixing the tire body 1 to the rim 8.

  The side portions 3 are wall surfaces formed at both ends in the tire width direction W via a tread portion 6 described later.

  The carcass layer 4 constitutes the side portion 3 and is a layer for withstanding a load and an impact and maintaining a tire structure. Further, both end portions of the carcass layer 4 are folded back to the bead portion 2.

  Three belt layers 5 are arranged in the tire circumferential direction between the carcass layer 4 and a tread portion 6 described later, and are for reinforcing the tire body 1. The three layers constituting the belt layer 5 will be described in detail later with reference to FIG.

  The tread portion 6 is a thick rubber layer that comes into contact with the road surface, and protects the carcass layer 4 and the belt layer 5.

  The wire chafer 7 is formed by coating a plurality of cords with rubber, and is disposed outside the carcass layer 4 folded back on the bead portion 2 to improve the durability of the bead portion 2. The wire chafer 7 will be described in detail later.

  FIG. 2 is a diagram showing the belt layer 5 in the present embodiment.

  In addition, the belt layer 5 is originally formed continuously in the tire circumferential direction 5, but in the same drawing, each layer is divided at different positions in order to facilitate explanation. Moreover, the figure is the figure which looked at the belt layer 5 in FIG. 1 from A direction.

  As shown in the figure, the belt layer 5 includes a first belt layer 5a, a second belt layer 5b, and a third belt layer 5c.

  The first belt layer 5a disposed on the inner side in the tire radial direction includes a plurality of first cords 50a disposed at an angle of 10 to 25 ° (angle x) with respect to the tire equator line CL, and the first belt layer 5a. The second belt layer 5b disposed on the outer side in the tire radial direction is inclined by 10 to 25 degrees (angle y) in a direction different from the first cord 50a with respect to the tire equator line CL. And the third belt layer 5c disposed on the outer side in the tire radial direction from the second belt layer is disposed at an inclination of 45 to 90 ° (angle z) with respect to the tire equator line CL. It has a plurality.

  In the figure, the first belt layer 5a is longer in the tire width direction than the second belt layer 5b, and the second belt layer 5b is longer in the tire width direction than the third belt layer 5c. However, the present invention is not limited to this.

  FIG. 3 is a diagram showing the bead unit 2 in the present embodiment.

  As shown in the figure, a carcass layer 4 is disposed on the outside of the bead portion 2, and a wire chafer 7 is disposed on the outside of the carcass layer 4.

  The folded end 4 a that is the end of the folded portion of the carcass layer 4 is on the inner side in the tire radial direction than the wire chafer folded end 7 a that is the end of the folded portion of the wire chafer 7. Further, the wire chafer 7 located on the outer side in the tire radial direction and the outer side in the tire width direction with respect to the folded end 4a is an end portion 7b. The end 7b will be described in detail later with reference to FIG.

  FIG. 4 is a diagram showing the end 7b in the present embodiment.

  As shown in FIG. 4A, a plurality of cords 9 are arranged at the end 7b.

  An interval 9a between the plurality of cords 9 and the cords 9 is 0.7 to 2.0 mm. Moreover, the diameter 9b of the cord 9 is 0.7 to 1.5 mm.

  FIG. 4B is a view of the end portion 7b in FIG. 3 as viewed from the B direction.

  The plurality of cords 9 constituting the end portion 7b are inclined by 0 to 45 ° (angle α) with respect to the tire circumferential direction S (with respect to the dotted line C extending in the tire circumferential direction in the figure).

(Operation and effect of the pneumatic tire according to the present embodiment)
In the pneumatic tire used for heavy loads according to the present embodiment, the pneumatic tire according to the present invention has three belt layers as compared with the belt layer that is normally laminated, so that the weight of the pneumatic tire is reduced. Can be achieved.

  Further, the cost can be reduced by making the belt layer, which has conventionally been used four layers, into three layers.

  Also, three layers of the first belt layer, the second belt layer, and the third belt layer are arranged from the inner side to the outer side in the tire radial direction, and the angle of the first cord constituting the first belt layer is relative to the tire equator line. The angle of the second cord constituting the second belt layer is 10 to 25 ° with respect to the tire equator line in the direction opposite to the first cord, and constitutes the third belt layer. Since the angle of the third cord is 45 to 90 ° with respect to the tire equator line, when the load is applied by laminating the first belt layer and the second belt layer, the two layers become tire widths. Since the third belt layer and the carcass layer having the cords arranged substantially in the tire width direction suppress the movement to shrink in the direction, durability in the belt layer can also be improved.

  Further, the folded end that is the end portion of the folded portion of the carcass layer is inside the tire radial direction from the wire chafer folded end that is the end portion of the folded portion of the wire chafer, and the outer side in the tire radial direction from the folded end and The cord constituting the wire chafer located on the outer side in the tire width direction is inclined by 0 to 45 ° with respect to the tire circumferential direction, has a diameter of 0.7 to 1.5 mm, and the distance between the cord and the cord is Since it is 0.7 to 2.0 mm, it is possible to follow the wire chafer cord with a crack that has occurred on the tire surface side and has occurred from the end of the carcass layer, which is a conventional failure factor. The durability can be improved. Further, by increasing the durability in the bead portion, it is possible to reduce the weight while securing the same durability as the current state by deleting the excess rubber.

  Furthermore, since the carcass layer in the bead portion is arranged 2 to 3 mm outside in the tire width direction due to the structure of the pneumatic tire as described above, when a load is applied to the tire and the tire is bent, it is more than conventional. Since the bead portion side is easily deformed, the force for deforming the belt layer is reduced, the loss in the belt layer is reduced, and the volume causing the loss of the bead portion is also reduced. % Can be reduced.

  Examples of the pneumatic tire 1 according to the embodiment of the present invention will be described in detail below.

  A pneumatic tire (Example 1) having a belt layer and a wire chafer of the present invention as shown in Table 1 is manufactured, and the weight of the pneumatic tire, rolling resistance, cost in manufacturing, and durability of the tire. The sex was investigated. For comparison, a pneumatic tire as shown in Table 1 (Comparative Example 1) was manufactured and investigated under the same conditions.

  The size of the pneumatic tire was 295 / 75R22.5.

<Weight>
The weights of the pneumatic tires of Example 1 and Comparative Example 1 described above were examined, and Comparative Example 1 was taken as 100 and indicated as an index. This numerical value indicates that the smaller the weight, the smaller the weight.

<Rolling resistance>
A normal load is applied to the pneumatic tires of Example 1 and Comparative Example 1 shown above, mounted on the vehicle, and the rolling resistance when traveling straight at a speed of 80 km / h is investigated. did. In addition, this figure has shown that there are so few rolling resistances that it is small.

  The regular load is a load corresponding to the maximum load capacity when a single wheel of Year Book 2004 version of JATMA (Japan Automobile Tire Association) is applied.

<Cost>
The pneumatic tires of Example 1 and Comparative Example 1 described above were manufactured, and the cost required to manufacture one of the pneumatic tires was calculated. In addition, this figure has shown that cost is so low that it is small.

<Durability>
The pneumatic tires of Example 1 and Comparative Example 1 shown above were manufactured, run on a drum at a speed of 60 km / h, the distance to failure was investigated, and Comparative Example 1 was indexed as 100. In addition, this figure has shown that it is excellent in durability, so that it is large.

  From the results in Table 1, it was found that Example 1 was reduced in weight, reduced in rolling resistance, and reduced in cost as compared with Comparative Example 1. Moreover, it turned out that Example 1 is maintaining durability compared with Comparative Example 1.

  Thus, it was found that the pneumatic tire as in Example 1 can improve the weight, rolling resistance, and cost while maintaining the durability.

It is sectional drawing which shows the tire main body which concerns on embodiment of this invention. It is a figure which shows the belt layer which concerns on embodiment of this invention. It is a figure which shows the bead part which concerns on embodiment of this invention. It is a figure which shows the edge part which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tire main body 2 ... Bead part 3 ... Side part 4 ... Carcass layer 4a ... Folding end 5 ... Belt layer 5a ... 1st belt layer 5b ... 2nd belt layer 5c ... 3rd belt layer 6 ... Tread part 7 ... Wire chain Fur 7a ... Wire chafer folding end 7b ... End 8 ... Rim 9 ... Cord 50a ... First cord 50b ... Second cord 50c ... Third cord

Claims (1)

A pneumatic tire having a wire chafer in which a plurality of cords are covered with rubber on the outside of the carcass layer folded along the bead core,
A first belt layer in which a plurality of first cords arranged with an inclination of 10 to 25 ° with respect to the tire equator line are covered with rubber;
A plurality of second cords, which are disposed at an inclination of 10 to 25 ° in a direction different from the first cord with respect to the tire equator line, are covered with rubber, and are disposed on the outer side in the tire radial direction than the first belt layer. A second belt layer,
A plurality of third cords disposed at an angle of 45 to 90 ° with respect to the tire equator line, and a third belt layer disposed on the outer side in the tire radial direction with respect to the second belt layer; ,
The folded end that is the end portion of the folded portion of the carcass layer is inside the tire radial direction from the wire chafer folded end that is the end portion of the folded portion of the wire chafer,
The cords constituting the wire chafer located on the outer side in the tire radial direction and the outer side in the tire width direction with respect to the folded end are inclined by 0 to 45 ° with respect to the tire circumferential direction, and have a diameter of 0.7 to 1. The pneumatic tire characterized by being 5 mm and the space | interval of the said code | cord | chord being 0.7-2.0 mm.

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