JP2006160121A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the generation of surface irregularity onto a tire side part, and apply a sufficient tensile resistance to the central part in the tire width direction. <P>SOLUTION: Reinforcing layers 9, 10 mainly composed of bent cords 8 wrigglingly extending in the circumferential direction are arranged on the outer peripheral side of a crown area of a carcass 5 toroidally extending between both bead cores 4. The reinforcing layers 9, 10 are composed of winding structures of ribbon-like strips 11, 12 which are rubber coated on a plurality of bent cords 8 disposed in parallel. Total strength at the width central area of the reinforcing layers 9, 10 is made to be larger than that at the both side part areas in the tire wherein respective bent cords in the ribbon-like strips 11, 12 are arranged by making a plurality of cords as one unit with a phase difference of 180 degree each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire suitable for use as a large vehicle tire filled with a high internal pressure and used under a high load, and in particular, prevents separation of a belt layer and generates heat in a tread shoulder portion. For the purpose of improving durability, in a tire provided with one or more reinforcing layers mainly composed of a detour cord that extends in the circumferential direction by being wavy in the tire width direction between the carcass and the belt layer, Tires that advantageously suppress uneven deformation that occurs in the side portions of the tire due to expansion and deformation of the detour cord due to filling of the tire with internal pressure, high-speed rotation of the tire, etc., without insufficient tensile strength of the reinforcing layer We propose a technology that prevents the deterioration of the appearance.

  As a conventional technique for suppressing the occurrence of the uneven waviness phenomenon on the side portion of the tire provided with the reinforcing layer, for example, the one disclosed in JP-A-4-328003 related to the applicant's previous proposal is disclosed. is there.

This tire is disposed between a carcass layer and a belt layer, and is internally reinforced with a plurality of reinforcing elements having substantially the same wavelength extending in parallel with the tire equatorial plane and bending in a wave shape. Comprising a layer, wherein the phases of the plurality of reinforcing elements among the reinforcing elements embedded in the reinforcing layer are different from the phases of the other reinforcing elements, When the tire is filled with internal pressure or when the tire is driven at high speed, each reinforcing element expands and deforms and generates a force in the direction that reverses every half wavelength. Since the phases of the reinforcing elements are different from each other, the force generated by the plurality of reinforcing elements is different in direction or magnitude from the force generated by the other reinforcing elements. Will give it Force is canceled out in dispersed or mutually circumferentially wavy amount of the carcass layer is reduced, irregularities in the outer surface of the sidewall portion is to be suppressed.
JP-A-4-328003

  However, in this prior art, the phases of a plurality of reinforcing elements embedded in the reinforcing layer are different from the phases of the other reinforcing elements, for example, by a half wavelength (180 °). When the number of reinforcing elements embedded in parallel in the reinforcing layer having a predetermined width is determined, the reinforcing elements are embedded in the reinforcing layer without a phase difference, for example, with a driving density of about 9 to 13/20 mm. Compared with this, there is inevitably a decrease of about 5% to 20%, which causes a problem of insufficient tensile strength of the entire reinforcing layer.

  That is, particularly in the case of a high flat tire with a flatness ratio of 60% or less, for example, when two reinforcing layers having a small number of reinforcing elements are arranged evenly, in particular, at the center in the width direction of the tire. There is a problem that the reinforcing effect is relatively insufficient, and the growth in the radial direction at the time of internal pressure filling cannot be effectively suppressed.

  The present invention has an object to solve such problems of the prior art, and the object of the invention is to effectively suppress surface irregularities generated on the side portion of the tire, The object of the present invention is to provide a pneumatic tire in which a reinforcing layer, in particular, a tensile strength as given in the center portion in the tire width direction is provided.

  In the pneumatic tire according to the present invention, a reinforcing layer mainly composed of a detour cord extending in the circumferential direction in a wavy shape is disposed on the outer peripheral side of the crown region of the carcass extending in a toroidal manner between both bead cores. A plurality of detour cords arranged in parallel are covered with rubber, for example, a ribbon-shaped strip winding structure having a width of 10 to 30 mm, and each detour cord in the ribbon-shaped strip is one or In a tire formed by arranging a plurality of units with a phase difference within a range of 90 to 270 °, for example, in a tire, the total strength of one or more reinforcing layers in the width central region is expressed in both side regions. It is made larger than that.

  That is, here, the total strength of the side regions of one or more reinforcing layers is inevitably lower than when there is no phase difference due to the phase difference being added to the detour cord.

  Here, the term “wavyly undulate” refers to any one of various extending modes that are continuously curved and bent in a form approximate to them, in addition to a sine wave shape, a rectangular wave shape, a triangular wave shape, and the like. The “ribbon-shaped strip winding structure” means that the ribbon-shaped strip is spirally formed in the width direction of the tire, without a gap or with a gap, or overlapped in a part of the width direction. In addition to what is wound, each of a plurality of ribbon-like strips is wound in the circumferential direction once or a plurality of times at a fixed position in the tire width direction.

  In addition, “the central region of the width of the reinforcing layer” means a range of 25 to 87% of the width centered on the center of the width of the maximum reinforcing layer, and “the total strength of the reinforcing layer” The tensile rupture load in the circumferential direction per 50 mm width of the reinforcing layer, specifically, the product of the breaking strength of the detour cord and the number of cord folds per 50 mm width.

  Here, the difference in the total strength of the reinforcing layer as described above is that the detour cord is driven into one or more reinforcing layers at 16 to 36/20 mm in the width central region and 8 to 12 in both side regions. By making this / 20 mm, it can be easily realized, and the difference can be as expected.

  In this case, if the number of detour cords having a phase difference between each other, which can be arranged in parallel in a ribbon strip having a predetermined width, is naturally limited, the difference in driving-in described above is It is preferable that the number of layers in the central region of the width be larger than that of the both side regions, more preferably three or more.

  By the way, when the reinforcing layer is formed by spiral winding of a ribbon-shaped strip, each of the winding start end and the terminal end of at least two layers of the reinforcing layer is positioned on the inner side in the width direction from the outermost edge of the reinforcing layer. It is preferable to make it.

  On the other hand, the required number of reinforcing layers is a fixed portion in the tire width direction of each of the plurality of ribbon-shaped strips having at least one of the length of one turn and the length of a plurality of turns. It can also be constituted by winding in the circumferential direction one or more times.

  In the pneumatic tire of the present invention, a plurality of detouring cords are arranged with a phase difference from each other in units of one or a plurality of cords in a ribbon-like strip that can be 10 to 30 mm wide, for example. In addition, since the reinforcing layer is formed of a wound structure in which the ribbon-shaped strip is spirally wound around the crown region of the carcass, for example, by filling the tire with internal pressure. Even if a force in the meridian direction of the tire is generated by the expansion and deformation of the detour cord due to the increase in the diameter of the detour cord, the force is generated in a ribbon shape with the detour cord arranged with a phase difference It will be well dispersed or absorbed within the width of the strip and will usually not affect the strip width.

  Therefore, even if the expansion ratio of the tire changes in the width direction due to the configuration of the belt layer, etc., the force in the meridian direction that is generated based on the extension deformation of the detour cord is offset. By completing within the width of the narrow ribbon-shaped strip, it is possible to sufficiently prevent the ribbon-shaped strip from exerting a force in the meridian direction on the adjacent strip portion and thus the carcass.

  On the other hand, here, the detour cord is disposed with a phase difference in the ribbon-like strip, thereby reducing the number of cords in the reinforcing layer, resulting in insufficient tensile strength of the reinforcing layer. It is possible to give the required reinforcing effect to the center part in the tire width direction, especially for high flat tires, by coping with the total strength in the width center area larger than that in both side areas. As a result, radial growth can be suppressed, and the tire can be excellent in durability and hard to be unevenly worn.

  It should be noted that, here, 16 to 36 lines / 20 mm of detour cords in the central region of the reinforcing layer, that is, the region within the range of 25 to 87% of the width of the maximum width reinforcing layer, was out of the central region of the width. When the detour cord driving in each side area is 8 to 12 pieces / 20 mm, the total strength of each area can be easily and reliably as expected, and The difference in their total strength can also be easily required.

  The required driving in each area, and hence the realization of the required total strength in those areas, is achieved by making the number of layers in the central area of the reinforcing layer larger than that in the two side areas. In order to ensure that the total strength in the center of the width is as expected, it can be carried out easily and adequately without fear of fretting of the cord. It is preferable that the number is three or more.

  By the way, in order to form at least two reinforcing layers, the ribbon-like strip is wound back and forth spirally in the tire width direction, without a gap or with a gap, or overlapping a part of the width. It is preferable to increase the construction work efficiency of the reinforcing layer, and in such winding of the ribbon-shaped strip, each of the winding start end and the terminal end of the winding strip is arranged to be wider than the outermost edge of the reinforcing layer. Positioning on the inner side in the direction can advantageously increase the tensile strength of the side region of the reinforcing layer as compared with the case where the starting end and the terminal end thereof face the side edge of the reinforcing layer.

  In addition, the reinforcing layer may be configured by winding each of a plurality of ribbon-shaped strips according to the configuration width thereof in the circumferential direction once or a plurality of times at a fixed position in the tire width direction. According to this, a reinforcing layer having a required number of layers can be easily formed in a required portion by simply winding each strip having a predetermined length with a time difference or by simultaneously winding the strip. be able to.

  In any of these, the occurrence of uneven deformation on the side portion of the tire can be effectively suppressed under the action of the detouring cord having a phase difference, and the selected total of the reinforcing layer can be suppressed. Under strength, it is always necessary to have a tensile strength over the entire width of the tire, and the possibility of insufficient strength at the center portion in the width direction of the tire can be sufficiently eliminated.

  In the pneumatic tire as described above, the phase difference of the detour cord in the ribbon-shaped strip is preferably 90 ° to 270 °. Within this angular range, it is possible to effectively cancel each other's meridian forces generated by the respective detour codes, which is particularly effective when the phase difference is 180 °.

  On the other hand, when the phase difference is less than 90 °, the vertices of the detour amplitude between the detour codes are close to each other and the combined amplitude is increased, so that it is difficult to sufficiently cancel the force in the meridian direction.

  FIG. 1 is a perspective view showing a half portion of the tire according to the present invention as a cross section. In FIG. 1, reference numeral 1 denotes a tread portion, and reference numeral 2 denotes a radially inward continuous side portion of the tread portion 1. The side wall portion extending to the inner side of the side wall portion 2 and a bead continuous to the inner peripheral side of the side wall portion 2 are shown.

  Here, between each bead core 4 disposed in the bead portion 3, a carcass 5 made of one or more carcass plies, for example, a radial carcass, is extended toroidal, and each side portion of the carcass 5 is connected to the bead core. 4 around the outer circumferential side of the crown region of the carcass 5 and mainly extending from the inner side in the radial direction, and the belt cord that is inclined with respect to the tire equator plane and extends linearly. For example, two belt layers 6 and 7 formed by covering these cords with rubber are arranged between them, with the belt cords extending in opposite directions with respect to the tire equatorial plane, for example, symmetrically. To do.

  Further, here, between the belt layers 6 and 7 and the carcass 5, the wavelength and the amplitude are continuously extended in the circumferential direction by undulating in the tire width direction on the outer peripheral side of the crown region of the carcass 5. In the figure, two or more reinforcing layers 9 and 10 are arranged, each of which is mainly composed of a plurality of detouring cords 8 with a constant value.

  The reinforcing layers 9 and 10 here are made of, for example, ribbon-like strips 11 and 12 each having a width of 20 mm, which are formed by applying rubber coating to a plurality of, for example, ten detour cords 8 arranged in parallel. In the ribbon-shaped strips 11, 12, a winding structure is formed by winding in a spiral or the like with no gap in the direction or with a gap or overlapping in a part in the width direction. For example, each of the eight detour cords 8 is arranged with a phase difference of 90 ° to 270 °, and 180 ° in the figure, in units of four. Thus, according to this strip structure, each of the eight detouring cords 8 extends to the object with respect to the center line in the width direction of the strips 11 and 12.

  When each of the reinforcing layers 9 and 10 is configured in this manner, the reinforcing layers 9 and 10 and, directly, the ribbon-like strips 11 and 12 are formed by, for example, deformation of the tire based on filling of the tire with internal pressure. As shown in FIG. 2, when each of the detouring cords 8 in the tire is extended and deformed by an equal amount, tires are generated in each of the peak portion and the valley portion of each of the detouring cords 8 along with the expansion and deformation. Since each force in the meridian direction is just canceled by each force generated by the four cords 8 located across the strip center line, the detour cord 8 and the reinforcing layer 9, The force generated due to the elongation deformation of 10 is erased within the width of the ribbon-like rubber strips 11 and 12.

  FIG. 3A is a partial plan view showing another configuration example of the ribbon-shaped strip including the circumflex cord under a perspective view of the detour cord, which is the respective detour cord 8 in the ribbon-shaped strips 11 and 12. Are arranged with a phase difference of ½ wavelength between adjacent cords, and the extending form of each detour cord 8 is symmetrical with respect to the strip center line. is there.

  Even in this strip structure, as shown in FIG. 3 (b), when all the detouring cords 8 are stretched by an equal amount, the meridian force generated by each cord 8 is equal to each other. Will be fully offset by the forces generated by the cords 8 adjacent to them, so that those forces will be erased in the ribbon strips 11,12.

  FIG. 4 is a plan view of an essential part showing still another configuration example of a ribbon-shaped strip including a detour cord. FIG. 4A shows, for example, four of eight detour cords 8 as a unit. In other words, the cords 8 are arranged with a phase difference of 90 degrees or 270 degrees, in other words, a quarter wavelength.

  Further, in the structure shown in FIG. 4B, eight cords 8 are arranged with a phase difference of 90 degrees or 270 degrees between adjacent cords 8 with one detour cord 8 as a unit. It is a thing.

  In any of these strip structures, the force in the meridian direction as shown by an arrow in the figure generated when the circumflex cord 8 is extended and deformed is the force generated by another cord 8 having a phase difference with respect to the cord. As in the case of the ribbon-shaped strip described above, it is possible to sufficiently achieve the elimination of the force in the strip.

  In addition, in the tire shown in FIG. 1, a narrow reinforcing layer 10 is provided on the wide reinforcing layer 9 on the inner layer side, and the area where the narrow reinforcing layer 10 is provided is the same as that of the wide reinforcing layer 9. Symmetrically with respect to the width center line, the total strength in the central region of the width of the two reinforcing layers 9 and 10 can be obtained by setting the required region within the range of 25 to 87% of the width W thereof. More preferably, the driving of the detour cord 8 in the central region of the width is 16 to 24/20 mm, and the driving in each side region is 8 to 12/20 mm.

  According to this, with respect to the inevitably decrease in the number of cords caused by arranging the detour cord 8 in the ribbon-shaped strips 11 and 12 with a phase difference, the tension resistance in the central region in the width direction of the tire is reduced. The decrease can be sufficiently compensated for by the narrow reinforcing layer 10 to give the central region the necessary tensile strength.

  By the way, in order to provide a required wave reinforcing structure, for example, the number of layers in the width central region can be three or more layers, and the number of side regions can be two layers. When a single ribbon-shaped strip is formed by spiral winding in the tire width direction, for example, as shown in a schematic cross-sectional view in the width direction in FIG. Is positioned in the middle of the tire width direction, and the strip 21 is spirally wound outward from the red face e toward one side region of the tire, and the spiral winding position is After reaching the predetermined side portion position, the winding direction of the spiral winding is set to the other side portion of the tire, the return winding is performed beyond the winding start end S, and the winding is performed at the predetermined side portion position. After reaching the above, further forward winding is performed, and the winding end E is changed to the previous forward winding. By positioning the front side than the turning point of the Domakikai, it is possible to realize a Weibyi reinforcing structure having a total strength, etc. as desired was.

  In addition, here, when one ribbon-like rubber strip 21 is wound in this way, both the winding start end S and the winding end E thereof are both inward in the width direction from the outermost edge of the reinforcing layer. It can also be positioned.

  Incidentally, in the place shown in FIG. 5, when the maximum width W of the reinforcing layer is 150 mm on each of the + side and the − side with respect to the equatorial plane e, for example, the winding start end S is 40 on the + side. The winding end E can be positioned in the range of 20 to 130 mm on the negative side.

  In addition, the above-mentioned Wavey reinforcement structure can also be comprised by winding each of the several ribbon-shaped strip which selected length previously in the circumferential direction.

  FIG. 6 is a schematic cross-sectional perspective view in the width direction showing an example. Here, for example, eight ribbon-shaped strips 31 to 38 are arranged at predetermined positions in the width direction of the tire, and the strip 31 is arranged. , 32 and 37, 38 each having a length of two circumferential turns, and each of the strips 34 to 36 having a length of three turns, each of the ribbon-like strips 31 to 38 is At the same time or with a time difference, it is a required reinforcement structure by winding and laminating twice or three times in the circumferential direction, and this also makes it easy to achieve the total strength etc. as expected, It can also be realized reliably.

  When the reinforcing layer of the standard tire of 435/50 R19.5 R166AZ is configured as follows, each of the example tire and the conventional tire is filled with the specified air pressure (900 kPa) defined in the standard. While measuring the diameter growth rate in the tread central region and the diameter growth rate in the tread side region, and measuring the surface unevenness of the tire side portion, the results shown in Table 1 were obtained.

<Reinforcing layer structure of Example tire>
Under the basic structure shown in FIG. 1, as shown in FIG. 5, a ribbon-like strip having a width of 20 mm in which the detour cord is arranged in the manner shown in FIG. 2 is overlapped with the adjacent strip portion over a width of 2 mm. By winding spirally, the maximum width of the reinforcing layer is set to 300 mm, the three-layer structure is set to 220 mm in the central area of the width, and the two-layer structure is set to 40 mm in the respective side areas. 120%.

<Conventional tire reinforcement layer structure>
As in the case described above, a ribbon-like strip having a width of 20 mm in which all of the detouring cords are arranged in parallel is spirally wound under an overlap width of 2 mm to form a two-layer reinforcing layer having a width of 300 mm. .

<Reinforcing structure of comparative tire>
Each detouring cord in the ribbon strip having a width of 20 mm is arranged with a half-wave phase difference in units of one cord, and the ribbon strip is spirally wound as in the case of a conventional tire. Turned to form a 300 mm wide two-layer reinforcing layer.
In this case, the total number of detour cords driven was 80% of the conventional tire.

According to the results shown in Table 1, in the example tire, the amount of surface unevenness generated in the tire side portion is effectively reduced, and the diameter growth rate in the central region of the width of the reinforcing layer, which still has a three-layer structure, is obtained. It turns out that it can suppress effectively.
In the comparative example tire, the reinforcing effect by the reinforcing layer is reduced over the entire reinforcing layer width as compared with the conventional tire. As a result, the diameter growth rate in the central region is considerably increased. It can be seen that the diameter growth rate in the region also increases.

1 is a partial cross-sectional perspective view showing a half part of a tire according to the present invention. It is a figure which shows the example of offset of the force accompanying the expansion deformation | transformation of a detour code. It is a fragmentary top view which shows the other structural example of a ribbon-shaped strip. It is a fragmentary top view which shows another structural example of a ribbon-shaped strip. It is an approximate line sectional view of the width direction which shows the example of composition of a wave reinforcement structure. It is a rough line section perspective view of the width direction which shows other examples of composition of a wave reinforcement structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Bead core part 5 Carcass 6, 7 Belt layer 8 Detour cord 9, 10, Reinforcement layer 11, 12, 21, 31-38 Ribbon-shaped strip S Winding end E Winding end e Equator surface

Claims (6)

Between the two bead cores, on the outer peripheral side of the crown region of the carcass extending in a toroidal manner, a reinforcing layer mainly composed of a detour cord that winds in a wavy shape and extends in the circumferential direction is disposed, and the reinforcing layers are arranged in parallel. Constructed by a ribbon-shaped strip winding structure with a rounded cord covered with a rubber coating, and each rounded cord in the ribbon-shaped strip is arranged with a phase difference between one or more. In the tire that is,
A pneumatic tire in which the total strength of one or more reinforcing layers is greater in the center region than in both side regions.   The pneumatic tire according to claim 1, wherein driving of the detour cord into one or more reinforcing layers is 16 to 36 pieces / 20 mm in the width central region and 8 to 12 pieces / 20 mm in both side regions.   The pneumatic tire according to claim 1 or 2, wherein the number of layers in the central region of the reinforcing layer is larger than that in both side regions.   The pneumatic tire according to claim 3, wherein the number of layers in the central region of the reinforcing layer is three or more.   The winding start end and the end of each of at least two layers of the reinforcing layer formed by spirally winding a ribbon-shaped strip are positioned on the inner side in the width direction from the outermost edge of the reinforcing layer. The pneumatic tire according to any one of the above.   The pneumatic according to any one of claims 1 to 4, wherein each of the plurality of ribbon-shaped strips comprises a reinforcing layer by one or a plurality of windings at a fixed position in the tire width direction. tire.

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