JP5077125B2 - Racing tire bias tire - Google Patents

Description

  The present invention relates to a bias tire for a racing cart, and more particularly, to a bias tire for a racing cart that is improved in handling stability without impairing air leakage resistance and damage resistance performance while reducing weight. .

  Generally, a pneumatic bias tire that travels on a circuit like a racing tire has a problem that it is difficult to ensure good steering stability due to insufficient bending rigidity in the sidewall portion. In particular, racing carts that run at ultra-high speeds on the circuit do not have a suspension mechanism, so this tendency is prominent and the front tire follows the steering angle of the steering wheel (hereinafter referred to as the steering wheel effect). There has been a problem that the fluttering and flow of the vehicle (hereinafter referred to as rear stability) is reduced due to the gripping force of the rear tire when traveling straight or cornering.

Conventionally, as a countermeasure, a weave woven fabric made of a rubber sheet, an organic fiber cord, or the like has been arranged on the sidewall portion (see, for example, Patent Document 1). However, these measures inevitably increase the tire weight, and at the same time, it is not possible to secure sufficient bending rigidity at the sidewalls, so that good steering stability, especially the steering wheel effect and rear stability, can be achieved. It is extremely difficult to obtain and further improvements have been sought.
JP 2008-24063 A

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and a racing cart that improves maneuvering stability without impairing air leakage resistance and trauma resistance while reducing weight. A bias tire is provided.

The racing cart bias tire of the present invention that achieves the above object comprises a pair of left and right bead portions, left and right sidewall portions connected to the bead portion, and a tread portion that connects the sidewall portions, and is embedded in the bead portion. In a racing cart bias tire in which a plurality of carcass layers whose cord directions cross each other from the inner side to the outer side of the bead core are folded around the bead core, the outer wall of the side wall portion is used as the outer wall of the carcass layer. It is arranged so as to be adjacent to the outside of the tire, and is composed of only a single fabric layer formed by rubber-coating a fabric of fiber filaments, and the fiber filaments are composed of monofilaments,
The lower end of the fabric layer is positioned on the side surface of the bead core, and the height of the upper end of the fabric layer is 50 to 90% of the tire cross-section height,
The lower end of the fabric layer is sandwiched between the folded portion of the carcass layer and the rim cushion rubber constituting the bead portion, and the lower end height is made lower than the rim flange height, and the upper end of the fabric layer is The carcass layer is sandwiched between the main body portion or the folded portion and the tread portion, and the overlap width between the fabric layer and the tread portion is at least 5 mm .

Furthermore, in the structure mentioned above, it is preferable to comprise as described in the following (1)-( 2 ).
(1 ) The fabric layer is composed of a plain weave fiber layer. In this case, the crossing angle of the warp and weft in the plain weave fiber layer is approximately 90 °, the weaving density of these warp and weft is 30 to 60 per 50 mm, and these warp and weft are in the tire circumferential direction. Arrange at 20-70 °.
( 2 ) The said fiber filament is comprised by 1 type chosen from nylon, vinylon, polyester, and steel.

According to the present invention described above, a single woven fabric is formed by arranging the outer wall of the sidewall portion of the bias tire for a racing cart so as to be adjacent to the outside of the folded portion of the carcass layer, and covering the woven fabric of fiber filaments with rubber. Since it is composed only of layers and the fiber filament is composed of monofilament , the bending rigidity of the sidewall portion is enhanced by the arrangement of the fabric layer that forms the outer wall, which is good even when traveling at high speed on the circuit The effectiveness of the handle and the stability of the rear can be ensured. In addition, instead of the conventional side tread rubber, only a single rubber-coated fabric layer is disposed on the outer wall of the side wall portion, so that air leakage resistance and damage resistance performance are suppressed while suppressing an increase in tire weight. Can be secured.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a half cross-sectional view showing a state in which a rim for a racing cart bias tire according to an embodiment of the present invention is assembled.

  In FIG. 1, a racing tire bias tire 1 for a racing cart according to the present invention includes a pair of left and right bead portions 2, 2 and left and right sidewall portions 3, 3 connected to bead portions 2, 2, and sidewall portions 3, 3. A plurality of carcass layers 5 that are composed of a portion 4, are wrapped around a bead core 7 embedded in the bead portion 2, and the cord directions cross each other from the inner side to the outer side of the tire are folded back. . In FIG. 1, in order to simplify the illustration, a plurality of carcass layers 5 whose code directions intersect with each other are indicated by a single line. In the figure, R indicates a rim.

  In the present invention, the outer wall of the side wall portion 3 is constituted by a single rubber-coated fabric layer 6 made of fiber filaments arranged adjacent to the outer side of the folded-back portion of the carcass layer 5. That is, in the racing cart bias tire 1 of the present invention, the side tread rubber layer is not disposed on the outer wall of the sidewall portion 3.

  In this way, the outer wall of the side wall portion 3 is composed only of a single rubber-coated fabric layer 6, so that the bending rigidity of the side wall portion 3 is increased by the arrangement of the fabric layer 6, and the circuit runs at high speed. Even in this case, it is possible to ensure good steering effectiveness and rear stability. In addition, instead of the conventional side tread rubber layer, a single rubber-coated fabric layer 6 is disposed on the outer wall of the side wall portion 3, so that air leakage resistance and damage resistance are suppressed while suppressing an increase in tire weight. Performance can be ensured.

  In the present invention, the lower end 6a of the fabric layer 6 is positioned on the side surface of the bead core 7, and the height H of the upper end 6b of the fabric layer 6 is 50 to 90%, preferably 60 to 80% of the tire cross-section height SH. It is good to set so that. Thereby, while suppressing the increase in a tire weight, favorable steering stability can be ensured, ensuring air leakage resistance and damage resistance.

  If the height H of the upper end 6b of the fabric layer 6 is less than 50% of the tire cross-section height SH, it is advantageous for weight reduction, but at the same time the steering rigidity is lowered due to insufficient bending rigidity of the sidewall portion 3, If the air leakage resistance is reduced and exceeds 90%, the tire weight increases, and at the same time, the bending rigidity of the sidewall portion 3 becomes too high and the steering stability is lowered.

  More preferably, the lower end 6a of the fabric layer 6 is sandwiched between the folded portion of the carcass layer 5 and the rim cushion rubber 2g constituting the bead portion 2, and the lower end 6a has a height h higher than the rim flange height Rh. While lowering, the upper end 6b of the fabric layer 6 is sandwiched between the main body portion or the folded portion of the carcass layer 5 (the main body portion of the carcass layer 5 in the figure) and the tread portion 4, and the fabric layer 6 and the tread portion 4 The overlapping width w (the overlapping width w between the upper end 6b of the fabric layer 6 and the terminal 4a of the tread portion 4) is at least 5 mm or more, preferably at least about 5 to 10 mm. Thereby, while peeling at the lower end 6a and the upper end 6b of the textile layer 6 can be prevented efficiently, the air leakage resistance and the damage resistance can be more reliably ensured.

  The fabric layer 6 described above is preferably composed of a plain weave fiber layer from the viewpoint of ensuring the bending rigidity in the sidewall portion 3. In this case, the crossing angle of the warp and weft in the plain weave fiber layer is approximately 90 °, and the weaving density of these warp and weft is set to 30 to 60, preferably 40 to 50 per 50 mm. It is good to arrange | position so that it may become 20-70 degrees with respect to a tire peripheral direction, Preferably it is 40-50 degrees. Here, the weaving density of the warp and the weft may be appropriately set each time in consideration of the relationship between the thickness of the warp and the weft and the elongation at break.

  Thereby, in the lift process at the time of tire molding or vulcanization, the expansion of the fabric layer 6 can be held uniformly with respect to the tire circumferential direction by the pantograph effect of warp and weft, so in the tire after vulcanization Uniformity is stable, and better steering effectiveness and rear stability can be secured.

  In the present invention, the fiber filament constituting the woven fabric layer 6 is preferably composed of a monofilament composed of one kind selected from nylon, vinylon, and polyester. Thereby, the bending rigidity of the side wall part 3 can be ensured appropriately. Furthermore, it is permissible to use steel monofilaments as fiber filaments.

  Here, when nylon, vinylon or polyester is used as the fiber filament, the thickness of monofilament and elongation at break are not particularly limited, but the thickness is about 470 to 490 dtex and elongation at break Is about 25 to 30%.

  In the present invention, it is allowed to use different types of filaments (materials, physical properties, etc.) for the fiber filaments constituting the warp and the weft in the fabric layer 6, but the lift during tire molding or vulcanization is allowed. From the viewpoint of effectively exhibiting the pantograph effect between the warp and the weft in the process, it is recommended to use the same filament for each of the warp and the weft.

  As described above, the racing tire bias tire 1 for a racing cart according to the present invention has a single rubber-covered fabric layer 6 made of fiber filaments arranged on the outer wall of the side wall portion 3 adjacent to the outer side of the folded portion of the carcass layer 5. It is easy to maintain good maneuvering stability even when driving on the circuit at high speed while maintaining weight reduction without impairing air leakage performance and damage resistance performance. Since it has an excellent effect in spite of its simple structure, it can be widely applied as a racing tire bias tire for a racing cart that runs at an ultra-high speed on a racing course.

There are two types of tire sizes, 4.5 × 10.0-5 and 7.1 × 11.0-5, and a conventional tire (conventional example) in which no fabric layer is disposed on the sidewall portion, and a sidewall portion. A comparative tire (comparative example) in which a plain woven fabric is arranged, and the tire structure as shown in FIG. 1, the outer wall of the sidewall portion is a plain woven fabric, and the height of the upper end of the plain woven fabric is as shown in Table 1. Different tires of the present invention (Examples 1 to 3) and reference tires (Reference Examples 1 to 2) were produced.

Incidentally, each tire polyester cord (1300 denier / 2, implantation density sixty / 50 mm) of the carcass layer of the two layers is arranged consisting of nylon monofilaments to plain-woven cloth in reference tires, compare tire and the present invention tires ( Thickness: 490 dtex / 1, weaving density 40/50 mm), and the arrangement angle of warp and weft was 45 ° with respect to the tire circumferential direction.

Further, the rubber thicknesses of the sidewall portions in the conventional tire and the comparative tire were set to 1 mm, respectively, and the rubber thicknesses of the covering rubber of the plain woven fabric in the comparative tire, the tire of the present invention, and the reference tire were set to 0.5 mm, respectively.

These seven types of tires, as well as measuring the weight of the tire, steering stability by the following test method evaluates the anti-air leakage performance and external damage performance, Table 1 by an exponential to 100 a conventional example and the results It was written together. Regarding the weight of the tire, the larger the value, the lighter the weight, and the higher the numerical value, the better the steering stability, air leakage resistance and damage resistance.

[Evaluation of steering stability]
Each tire is assembled with a rim and filled with air pressure of 100 kPa. A tire having a size of 4.5 × 10.0-5 is used as a front wheel of the vehicle, and a tire having a size of 7.1 × 11.0-5 is used as a vehicle. Each was mounted on the rear wheel, and the circuit was run for 30 km at an average speed of 80 km / h. Through this run, sensory evaluation was performed by three skilled test drivers from both aspects of steering effectiveness and rear stability. The results were used to evaluate the handling stability.

[Evaluation of air leakage resistance]
The air pressure in each of the tires after running described above was measured, and the result was used as an evaluation of air leakage resistance.

[Evaluation of trauma resistance]
The situation (number and size) of the trauma generated in the sidewall portion of each tire after traveling described above was observed with the naked eye, and the result was used as the evaluation of the trauma resistance.

  From Table 1, it can be seen that the tire of the present invention has improved steering stability without impairing air leakage resistance and trauma resistance while maintaining weight reduction as compared with the conventional tire.

1 is a half cross-sectional view showing a state in which a rim for a racing tire for a racing cart according to an embodiment of the present invention is assembled.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bias tire for racing carts 2 Bead part 2g Rim cushion rubber 3 Side wall part 4 Tread part 5 Carcass layer 6 Fabric layer 6a Lower end 6b Upper end 7 Bead core H Height of upper end of fabric layer h Height of lower end of fabric layer SH tire Section height R Rim Rh Rim flange height

Claims (4)

It consists of a pair of left and right bead parts, left and right side wall parts connected to the bead part, and a tread part connecting the side wall parts, around the bead core embedded in the bead part, between the layers from the inside to the outside of the tire. In a racing cart bias tire in which a plurality of carcass layers whose cord directions cross each other are folded,
The outer wall of the side wall portion is arranged so as to be adjacent to the tire outer side of the folded portion of the carcass layer, and is composed of only a single fabric layer formed by rubber-coating a fabric of fiber filaments, and the fiber filaments Composed of monofilament,
The lower end of the fabric layer is positioned on the side surface of the bead core, and the height of the upper end of the fabric layer is 50 to 90% of the tire cross-section height,
The lower end of the fabric layer is sandwiched between the folded portion of the carcass layer and the rim cushion rubber constituting the bead portion, and the lower end height is made lower than the rim flange height, and the upper end of the fabric layer is A racing tire bias tire for a racing cart that is sandwiched between a main body portion or a folded portion of the carcass layer and the tread portion, and an overlapping width of the fabric layer and the tread portion is at least 5 mm . The bias tire for a racing cart according to claim 1 , wherein the woven fabric layer is composed of a plain woven fiber layer. The intersecting angle of the warp and weft in the plain weave fiber layer is about 90 °, the weaving density of these warp and weft is 30-60 per 50 mm, and these warp and weft are 20-70 ° with respect to the tire circumferential direction. The racing tire bias tire for a racing cart according to claim 2 , which is disposed in The racing tire bias tire according to any one of claims 1 to 3 , wherein the fiber filament is made of one selected from nylon, vinylon, polyester, and steel.

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