JP5440320B2 - Heavy duty pneumatic bias tire - Google Patents

Description

  The present invention relates to a heavy-duty pneumatic bias tire using a steel cord in an overhead structure outside a carcass, and more specifically, used for a construction vehicle used at an industrial waste treatment site or the like, and a high lift (tire diameter) during vulcanization. The present invention relates to a heavy-duty pneumatic bias tire that can follow a large expansion in the direction), achieve both cut resistance and separation resistance, and consequently improve durability.

  Conventionally, in pneumatic bias tires for construction vehicles (hereinafter simply referred to as “bias tires”), an overhead in which nylon fibers are coated on the outside of a carcass is disposed, but the cut resistance (puncture resistance) is not sufficient. In particular, for bias tires, a technique for preventing puncture at an industrial waste processing site or the like is desired. For this reason, in the bias tire, various proposals have been made regarding an overhead structure using a steel cord for improving cut resistance (see Patent Documents 1 and 2).

  In Patent Literature 1, in a pneumatic bias tire for a construction vehicle, at least two layers of a steel cross belt layer (steel breaker) made of rubber-coated steel cords crossing each other are arranged outside the carcass, and steel outside the steel bias belt tire. Nylon monofilament layer (nylon monofilament breaker) with a flat, rubber-coated cross section that intersects with the breaker is disposed beyond the steel breaker width with the major axis of the flat section cord aligned in the tire cross-sectional direction. Therefore, even if it receives an injury such as penetration of moisture, separation resistance is ensured, a desirable carcass shape can be set, and a light breaker structure can be obtained.

  Further, in Patent Document 2 related to the application of the present applicant, in the heavy duty pneumatic tire, on the outer peripheral side of the carcass layer in the tread portion (crown portion), more specifically, on the outer side of the breaker layer made of an organic fiber cord, Mitigating impact by embedding a tread protection layer (steel breaker) consisting of a flat coil steel cord that overlaps several loops one after the other, and defining the number of laps where the steel cord coil overlaps within a specified range It is said that durability can be improved and durability, particularly cut resistance, cut-through resistance and separation resistance can be improved.

Japanese Patent Laid-Open No. 7-156613 JP 2004-196095 A

By the way, in Patent Document 1, in order to improve the cut resistance, a steel cross belt layer is disposed as a breaker on the outside of the carcass, and the separation resistance due to the penetration of moisture from the trauma, which decreases due to this, is improved. The nylon monofilament breaker is arranged on the outermost layer of the breaker. However, since the steel cross belt layer is arranged outside the carcass, it is difficult to follow the high lift of the bias tire (molding → vulcanization, about 200%), and the tire vulcanization failure is likely to occur. was there.
Further, in Patent Document 2, since the coil wire is arranged in the tread portion, the puncture frequency can be greatly improved. However, since the coil wire is used, the productivity is poor, the production cost is increased, and the heavy load bias tire. There was a problem that the cost of the.

  The present invention solves the above-mentioned problems of the prior art and provides a technique for preventing puncture at an industrial waste treatment site or the like desired for a heavy-duty pneumatic bias tire used for construction vehicles. By placing the steel layer with the cord structure, angle, width, cord spacing and placement position in the overhead, the tire's cut resistance can be improved without increasing tire vulcanization failure, and productivity An object of the present invention is to provide a heavy-duty pneumatic bias tire that is good and does not increase production costs.

  In order to achieve the above object, a heavy-duty pneumatic bias tire according to the present invention is a heavy-duty pneumatic tire in which a steel layer is disposed on a bias carcass layer, and the steel cord of the steel layer extends in the tire circumferential direction. An arrangement angle is 85 to 90 degrees, and a distance between the steel cords is 2 mm or more.

Here, the steel cord is preferably a steel cord with a wrapping wire.
Moreover, it is preferable that the width of the steel layer in the tire width direction is not less than 100 mm and not more than the tread development width.
Moreover, it is preferable to arrange | position a nylon overhead layer on the said steel layer.
Further, the nylon overhead layer is preferably arranged wider than the steel layer by 60 mm or more in the tire width direction.

According to the present invention, a steel layer that specifies the structure, angle, width, cord interval and position of the steel cord is placed in the overhead to follow high lift during vulcanization (large expansion in the tire radial direction). It is possible to achieve both cut resistance and separation resistance, and as a result, durability can be improved.
Further, according to the present invention, it is possible to improve the cut resistance of the tire without increasing the tire vulcanization failure, and the productivity is good, the production cost is not increased, and the low cost. A heavy-duty pneumatic bias tire can be provided.
Furthermore, according to the present invention, it is possible to prevent puncture at an industrial waste processing site or the like. In particular, when a steel cord with a wrapping wire is used as the steel cord, it is possible to provide a heavy-duty pneumatic bias tire that does not bend even when stepping on a reinforcing bar or the like at an industrial waste disposal site or the like.

It is sectional drawing which shows the cross-sectional shape of the right half with respect to the meridian CL of one Embodiment of the heavy-bias pneumatic bias tire which concerns on this invention. It is an enlarged view which shows typically the principal part of the heavy-bias pneumatic bias tire shown in FIG. It is an enlarged view which shows typically the principal part of other embodiment of the heavy-bias pneumatic bias tire which concerns on this invention.

Hereinafter, the heavy duty pneumatic bias tire of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.
FIG. 1 is a cross-sectional view showing a right half cross-sectional shape with respect to the meridian CL of one embodiment of the heavy load pneumatic bias tire of the present invention, and FIG. 2 is a diagram of the heavy load pneumatic bias tire shown in FIG. It is an enlarged view which shows a principal part typically.

A heavy load pneumatic bias tire (hereinafter simply referred to as a bias tire) 10 shown in FIG. 1 is used as a construction vehicle pneumatic bias tire at an industrial waste disposal site or the like, and includes a tread portion 12, a shoulder portion 14, and a side tire. The wall portion 16 and the bead portion 18 are included as main components. In addition, CL is a tire meridian. The left half of the tire on the left side of the meridian CL not shown in FIG. 1 has the same configuration.
In the following description, as indicated by arrows in FIG. 1, the tire width direction refers to a direction parallel to the tire rotation axis, and the tire radial direction refers to a direction orthogonal to the rotation axis. Further, the tire circumferential direction refers to the direction of rotation with the rotation axis as the axis serving as the center of rotation. Further, the tire inner side means the lower side of the tire in FIG. 1 in the tire radial direction, that is, the tire inner side facing the cavity region R that applies a predetermined internal pressure to the tire, and the tire outer side means the upper side of the tire in FIG. That is, it means a tire outer surface side that can be visually recognized by the user on the side opposite to the tire inner peripheral surface.

  The tire 10 includes a bias carcass layer (hereinafter simply referred to as a carcass layer) 20, an overhead 26 including a steel layer 22 and a nylon overhead layer 24, a bead core 28, a bead filler 30, a tread rubber layer 32, and sidewall rubber. It mainly has a layer 34, a rim cushion rubber layer 36, and an inner liner rubber layer 38. Of course, the left half of the tire not shown in FIG. 1 has the same configuration as described above.

  A plurality of carcass layers 20 are mounted between the pair of left and right bead portions 18. These carcass layers 20 have a configuration in which reinforcing cords made of organic fibers are arranged so as to be inclined with respect to the tire width direction at regular intervals and covered with a cord coating rubber so that the reinforcing cords cross each other between the layers. Are stacked. In each bead portion 18, three sets of bead cores 28 are embedded, and both end portions of the carcass layer 20 are folded back from the inner side of the tire so as to sandwich the bead filler 30 around the bead cores 28. An inner liner rubber layer 38 is provided between the left and right bead portions 18 inside the carcass layer 20.

  The carcass layer 20 is not particularly limited as long as it is used for a heavy duty pneumatic bias tire, and a conventionally known carcass layer can be used. That is, the material, size, arrangement direction, arrangement interval, driving density, and the like of the reinforcing cord constituting the carcass layer 20 are not particularly limited, and may be anything, such as a conventionally known reinforcing cord material or It may be size, arrangement direction, arrangement interval, driving density, and the like. Further, the number of layers of the carcass layer 20 is not particularly limited and may be any number, but is preferably an even layer, and may be appropriately selected according to, for example, a tire size or a structure.

Further, as shown in detail in FIG. 2, a steel layer 22 is embedded on the outer peripheral side of the carcass layer 20 between the left and right shoulder portions 14, and the steel layer 22 is covered on the outer peripheral side of the steel layer 22. Thus, a nylon overhead layer 24 in which a nylon fiber cord is covered with rubber is embedded.
Note that the tire 10 of the present embodiment has an overhead (26) composed of a steel layer 22 and a nylon overhead layer 24. The steel layer 22, the nylon overhead layer 24, and the overhead 26 of the present invention correspond to a steel breaker, an organic fiber breaker, and a breaker, respectively.

In addition to this, the tire 10 is a rubber material, on the outer peripheral side of the overhead 26, a tread rubber layer 32 that constitutes the tread portion 12, a sidewall rubber layer 34 that constitutes the sidewall portion 16, and a rim cushion rubber layer 36, And an inner liner rubber layer 38 provided on the inner circumferential surface of the tire.
In the tire 10 of the present invention, the configuration of a conventionally known heavy-duty pneumatic bias tire can be applied except for the overhead 26, particularly the steel layer 22.

The steel layer 22 that is a feature of the present invention of the overhead 26 of the present embodiment will be described.
In the present invention, a steel layer 22 is disposed as an overhead 26 on the outside of the bias carcass layer 20, and an arrangement angle of the steel cord constituting the steel layer 22 with respect to the tire circumferential direction is 85 to 90 degrees, and the steel cord The interval is 2 mm or more.

The steel layer 22 of the present invention functions as a breaker for the bias tire 10 outside the carcass layer composed of a plurality of layers and improves cut resistance, that is, puncture resistance. It is possible to follow a high lift of about 200% of the bias tire in the process from molding to vulcanization by setting the angle of arrangement with respect to the tire circumferential direction to an angle of 85 to 90 degrees orthogonal or substantially orthogonal. It is possible to prevent tire vulcanization failure and improve the separation resistance by making the distance between the steel cords 2 mm or more to achieve both cut resistance and separation resistance. It is something that can be done.
In other words, the steel layer 22 of the present invention can improve the point that it cannot follow the high lift of the bias tire, which is a problem in the steel breaker having the steel cross belt structure disclosed in the cited document 1, and the tire vulcanization failure Can be eliminated.

Therefore, in this invention, it is necessary to limit the arrangement | positioning angle with respect to the tire circumferential direction of the steel cord which comprises the steel layer 22 to 85-90 degree | times. In the present invention, the arrangement angle of the steel cord with respect to the tire circumferential direction refers to the smaller angle of the angles formed by the steel cord and the tire circumferential direction. Therefore, the arrangement angle of the steel cord is 90 degrees (orthogonal) or less, and there is no more than 90 degrees.
In the present invention, the reason why the arrangement angle of the steel cord is limited to 85 to 90 degrees is that if the arrangement angle of the steel cord is less than 85 degrees, that is, out of the limited range, the bias tire 200 in the vulcanization process from the forming process is reduced. This is because it is impossible to follow a high lift of about% and tire vulcanization failure such as the occurrence of porosity cannot be reduced.

Further, in the present invention, in order to improve and secure the separation resistance, it is necessary to set the distance between the steel cords to 2 mm or more. The reason is that if the distance is less than 2 mm, the separation resistance is deteriorated and the cut resistance is reduced. This is because the separation resistance and the separation resistance cannot be compatible.
On the other hand, the upper limit of the distance between the steel cords is not particularly limited, but is preferably 50 mm when emphasizing puncture resistance. That is, the distance between the steel cords is preferably 2 to 50 mm, more preferably 2 to 20 mm, and most preferably 2 to 10 mm.

  In the present invention, the steel layer 22 may be composed of a single layer or a plurality of layers, and the number of layers is not particularly limited, but is preferably 1 to 4 layers. By using multiple layers, the degree of reinforcement increases, but the weight increases, so it is better to have 4 layers or less, and to obtain the necessary degree of reinforcement, if the steel cord driving density can be increased, it is composed of one layer. Most preferably.

  Further, the steel layer 22 is preferably arranged so that the center in the tire width direction is aligned with the meridian of the tire 10 in accordance with CL. Further, the width of the steel layer 22, that is, the length in the tire width direction, is 100 mm or more (50 or more in the right half shown in FIG. 1) with the center thereof aligned with the meridian CL of the tire 10, and the tread portion 12. It is preferable that the width is not more than the tread width. The reason is that if the thickness is less than 100 mm, it becomes difficult to obtain a remarkable reinforcing effect, and if the width exceeds the tread deployment width, the effect is saturated.

  The steel cord used for the steel layer 22 of the present invention has a cord structure in which a plurality of strands are twisted together, and the periphery of each strand is covered with a coating rubber. Here, the cord structure of the steel cord used in the present invention may be, for example, a double twist cord structure such as 7x7, 3x7, or a single twist cord structure such as 3 + 9 + 15, 3 + 8. A structure can be used. That is, the twist pitch and twist angle of the steel cord, the wire size (wire diameter) and the like are not particularly limited.

As described above, a steel cord having a conventionally known twisted structure can be used as the steel cord used in the present invention. However, it is preferable to use a steel cord with a wrapping wire wrapped with a single wire on the steel cord.
In the present invention, the reason why the steel cord with the wrapping wire is used is that the bias tire 10 is less likely to bend and bend even if the rebar is stepped on the industrial waste disposal site or the like.
Examples of the steel cord with wrapping wire used here include 7 × 7 + 1, 3 + 8 + 1, and the like.

  Here, the wrapping pitch of the wrapping wire is preferably 2.5 to 8 mm, and the size (wire diameter) of the wrapping wire is preferably 0.15 to 0.17 mm. The reason why these ranges are limited as preferable ranges is that the steel cord with a wrapping wire can secure the effect of preventing the seat from being bent.

  In the present invention, as shown in FIG. 2, in addition to arranging the steel layer 22 on the outer peripheral side of the carcass layer 20 as the overhead 26, the nylon overhead made of nylon fiber cords on the outer peripheral side of the steel layer 22 Layer 24 is preferably disposed. The reason for this is to maintain and improve separation resistance and to achieve both cut resistance and separation resistance. Here, as the nylon fiber cord, a multifilament cord obtained by twisting a plurality of thin filaments of nylon fiber may be used, or the nylon monofilament cord disclosed in the cited document 1 may be used. A code can be used.

  As the nylon overhead layer 24, for example, one nylon layer having 6 nylon 940 dtex / 2, driving density 23 pieces / 50 mm, an arrangement angle 35 degrees with respect to the tire circumferential direction, and a width of 500 mm can be used. In the present invention, the nylon layer constituting the nylon overhead layer 24 is not limited to this, and the material of the nylon layer is not particularly limited as long as it is nylon, and there are a plurality of nylon layers. It may be a layer. Further, the cord thickness of the nylon fiber cord of the nylon layer is preferably 1000 to 3000 dtex in terms of the total fineness, the driving density is preferably 15 to 50/50 mm, and the arrangement angle with respect to the tire circumferential direction is It is preferably 25 to 50 degrees.

In the present invention, when the overhead 26 includes the steel layer 22 and the nylon overhead layer 24, the nylon overhead layer 24 is preferably disposed wider than the steel layer 22 by 60 mm or more in the tire width direction. Since the nylon overhead layer 24 is also preferably arranged with its center in the tire width direction aligned with the meridian CL of the tire 10, the right half shown in FIG. It is good to arrange 30 mm or more wide in the tire width direction.
The reason is that the steel layer 22 is covered with the nylon overhead layer 24 to protect the steel layer, further improve the separation resistance, and achieve further compatibility between cut resistance and separation resistance.

  In the example shown in FIGS. 1 and 2, the steel layer 22 and the nylon overhead layer 24 are disposed on the outer peripheral side of the carcass layer 20 as the overhead 26, but the present invention is not limited to this, and FIG. As shown in FIG. 3, only the steel layer 22 may be disposed on the outer peripheral side of the carcass layer 20.

〔Example〕
The effect of the heavy load pneumatic bias tire of the present invention was examined using a pneumatic bias tire for construction vehicles having a tire size of 23.5-2516.
As shown in Table 1, by changing the configuration of the overhead structure in the bias tire and the arrangement angle of the steel cord of the steel cord with respect to the tire circumferential direction, the spacing of the steel cord, etc., Conventional Example 1, Examples 1 to 6, and comparison Evaluation tires of Examples 1 and 2 were prepared, and the vulcanization failure resistance and puncture resistance of each evaluation tire were measured. The results are shown in Table 1.

In Table 1, the tire of Conventional Example 1 is the one in which only the nylon overhead layer 24 is disposed on the outer peripheral side of the carcass layer 20 as the overhead 26, and the steel layer 22 is not disposed. It was not satisfied. The vulcanization failure resistance and puncture resistance of the tires of Conventional Example 1 were set to 100, and the vulcanization failure resistance and puncture resistance of the evaluation tires of Examples 1 to 6 and Comparative Examples 1 and 2 were evaluated.
The nylon overhead layer of the overhead structure shown in Table 1 was composed of one nylon layer of 6 nylon 940 dtex / 2, driving density 23 pieces / 50 mm, an arrangement angle 35 degrees with respect to the tire circumferential direction, and a width of 500 mm.

Here, the vulcanization failure resistance was evaluated as follows.
The evaluation tire of each example was put in a vacuum chamber (5 kPa), and the entire circumference of the crown part was radiographed, and the following three-stage evaluation was performed. Ten evaluation tires of each example were measured and the points were totaled, and the index was expressed as an index with the conventional example 1 as 100. Therefore, vulcanization failure resistance indicates that the larger the index, the better.
1 point: There is a gap of 5 mm or more.
2 points: There are gaps of less than 1 to 5 mm.
3 points: The gap is less than 1 mm.
Next, puncture resistance was evaluated as follows.
Each evaluation tire of each example was mounted on a wheel loader, traveled at an industrial waste disposal site, and the travel distance to puncture was recorded. The running distances of 10 evaluation tires in each example were totaled and expressed as an index with the conventional example 1 as 100. Therefore, it shows that puncture resistance is so favorable that an index is large.

  As is apparent from Table 1, the evaluation tire of Example 1 has a two-layer structure in which the overhead structure is a nylon layer (nylon overhead layer) and a steel layer, and the steel cord of the steel layer is 3 + 9 + 15 × 0.17 + 0.15. The steel cord with wrapping wire whose cord structure is shown in FIG. 1, the arrangement angle of the steel cord, the distance between the steel cords, and the width of the steel layer are 90 degrees (orthogonal), 5 mm and 420 mm, respectively, and the nylon layer is Since it is 80 mm wider than the steel layer and satisfies the limited range of the present invention, the vulcanization failure resistance of Example 1 is 100, similar to the evaluation tire of the conventional example, whereas that of the conventional example. The puncture resistance of Example 1 is 130 with respect to the puncture resistance 100, and the vulcanization failure resistance of the tire is not deteriorated. It can be seen that sex is greatly improved.

  The evaluation tire of Example 2 has a two-layer structure in which the overhead structure is a steel layer, and the steel cord of the steel layer is a steel cord with a wrapping wire represented by 3 + 8 × 0.22 + 0.15. Since the arrangement angle, the distance between the steel cords, and the width of the steel layer are 88 degrees for the upper and lower layers, 9 mm for the upper and lower layers, 300 mm for the upper layer, and 420 mm for the lower layer, respectively. The vulcanization failure resistance of Example 2 is 100 as in the case of the evaluation tire of the conventional example, whereas the puncture resistance of Example 2 is 125 with respect to the puncture resistance 100 of the conventional example. As in Example 1, it can be seen that the puncture resistance is greatly improved without deteriorating the vulcanization failure resistance of the tire.

  The evaluation tire of Example 3 is a steel cord with a wrapping wire whose steel cord is represented by 3 + 8 × 0.22 + 0.15, and the evaluation of Example 4 except that the width of the steel layer is 480 mm. The tire is the same as the evaluation tire of Example 1 except that the overhead structure is a one-layer structure of a steel layer and the steel cord is a steel cord with a wrapping wire represented by 3 + 8 × 0.22 + 0.15. Yes, as in Example 1, it satisfies the limited range of the present invention, and it can be seen that the durability of the tire is improved without deteriorating the vulcanization failure resistance of the tire. Separation is observed, and the puncture resistances of Examples 3 and 4 are 120 and 110, respectively, which are lower than those of Example 1.

  In addition, the evaluation tire of Example 5 is a steel cord having a steel cord of 3 + 9 + 15 × 0.17, in which a wrapping wire is not wound, except that the distance between the steel cords is 6 mm. The evaluation tire of No. 6 is the same as the evaluation tire of Example 1 except that the distance between the steel cords is 20 mm, and, like Example 1, satisfies the limited range of the present invention. It can be seen that the durability of the tire has been improved without deteriorating the vulcanization failure resistance of Example 5, but in Example 5, a slight cord breakage was observed, and the puncture resistance of Examples 3 and 4 was It is 105 and 110, respectively, which is found to be lower than that of Example 1.

On the other hand, the evaluation tire of Comparative Example 1 is the same as Example 1 except for the cord structure of the steel cord and the arrangement angle of the steel cord, but the arrangement angle of the steel cord is 80 degrees. Since the puncture resistance is good because it is out of the limited range, it cannot follow the high lift in the process from molding to vulcanization, and the vulcanization failure resistance becomes 85, which is worse than the conventional example 1. The evaluation tire of Comparative Example 2 is the same as Example 1 except for the distance between the steel cords, but the distance between the steel cords is 1 mm and is smaller than the lower limit value of the limited range of the present invention. Although the failure is not deteriorated, the separation resistance is deteriorated and the puncture resistance is 95, which is worse than that of the conventional example 1.
From the above, the example of the present invention has the effect of improving the puncture resistance without deteriorating the vulcanization failure resistance of the tire as compared with the comparative example, and the effect of the present invention is clear.

  The pneumatic radial tire of the present invention has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various improvements and modifications may be made without departing from the spirit of the present invention. It is.

10 Pneumatic bias tire for heavy loads (tire)
12 Tread portion 14 Shoulder portion 16 Side wall portion 18 Bead portion 20 Carcass layer 22 Steel layer 24 Nylon overhead layer 26 Overhead 28 Bead core 30 Bead filler 32 Tread rubber layer 34 Side wall rubber layer 36 Rim cushion rubber layer 38 Inner liner rubber layer

Claims (5)

A heavy duty pneumatic tire having a steel layer disposed on a bias carcass layer,
The heavy load pneumatic bias tire, wherein an angle of arrangement of the steel layer with respect to a tire circumferential direction of the steel cord is 85 to 90 degrees, and an interval between the steel cords is 2 mm or more.   The heavy load pneumatic bias tire according to claim 1, wherein the steel cord is a steel cord with a wrapping wire.   3. The heavy-duty pneumatic bias tire according to claim 1, wherein a width of the steel layer in the tire width direction is not less than 100 mm and not more than a tread development width.   The heavy load pneumatic bias tire according to any one of claims 1 to 3, wherein a nylon overhead layer is disposed on the steel layer.   The heavy load pneumatic bias tire according to any one of claims 1 to 4, wherein the nylon overhead layer is disposed 60 mm or more wider in the tire width direction than the steel layer.

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