JP6953822B2 - Pneumatic bias tire - Google Patents

Description

The present invention relates to a pneumatic bias tire.

Generally, tires for industrial vehicles have a high load and are set to high pressure. For example, a heavy-duty bias tire used for a gantry crane or the like used in a harbor or the like has a high load setting and a high center of gravity. Therefore, such a bias tire is susceptible to an eccentric load, and the vehicle may wobble or tire failure due to excessive deflection. However, it is difficult to set a higher pressure due to problems with wheel strength and operation management.

By the way, Patent Document 1 discloses a technique for disposing a reinforcing layer between a carcass ply and a bead core in order to improve the durability of the bead portion. The reinforcing layer disclosed in Patent Document 1 is made of an organic fiber cord and rubber.

JP-A-2007-069850

In heavy-duty bias tires, the load on the carcass around the bead tends to increase as the torque increases due to recent vehicle evolution. In particular, in a WB (Wide Base) size bias tire having a low flatness, which is used under an overload condition, cord breakage or privacy may occur. Cord Broken Up (hereinafter referred to as CBU) causes the carcass ply to come into strong contact with the winding end of the steel wire of the bead core at the innermost point in the tire axial direction, leading to breakage. CBU is generated by excessive tension of the bead and carcass on the innermost surface side in the tire width direction.

The pre-separation is peeling fracture between the bead filler and the carcass provided in contact with the bead filler. Prescription occurs due to distortion between the inner carcass layer near the tire equatorial plane and the outer carcass layer far from the tire equatorial plane in the tire width direction.

As a general measure, it is conceivable to increase the number of carcass so that it can withstand excessive tension. However, this measure leads to poor productivity, increased cost, and increased weight.

The technique disclosed in Patent Document 1 is a technique applied to a radial tire having a sandwiching bead structure. Therefore, the technique disclosed in Patent Document 1 cannot be applied to cases where the bead structure is different or to a bias tire.

The present invention has been made in view of the above, and an object of the present invention is to provide a pneumatic bias tire capable of improving durability without increasing the number of carcass by arranging a reinforcing layer at an appropriate position. To provide.

In order to solve the above-mentioned problems and achieve the object, the pneumatic bias tire according to an embodiment of the present invention includes a plurality of pairs of bead cores and a plurality of carcass layers provided corresponding to the plurality of pairs of bead cores. The plurality of carcass layers include a belt layer provided on the outer side of the carcass layer in the tire radial direction, and each of the plurality of carcass layers is formed by laminating a plurality of carcass plies, and any of the plurality of carcass plies. It has a plurality of laminated fiber reinforcing layers extending adjacent to each other between the plies , and the plurality of fiber reinforcing layers are located at a position 0.8 times the height of the rim flange in the cross section in the tire meridional direction. set between the up to 1.5 times the position of the rim flange height vignetting, further the fiber reinforcing layer, in the cross section of the tire meridian direction, corresponding to the carcass layer in which the fiber reinforced layer is provided bead core the after involving the tire width direction inner side, of the tire width direction outer end extending by winding the bead core, to the tire width direction inner side of the other end is a front end winding, the other end, Among the belts constituting the belt layer, the outermost part in the tire width direction is inside the tire radial direction, and the one end is located inside the tire radial direction from the end portion of the carcass ply adjacent to the fiber reinforcing layer. near is, the plurality of fibrous reinforcing layers each comprises code, the plurality of fibrous reinforcing layer, the angle is different from each other with respect to the tire circumferential direction of the cord, in the stacking direction of the plurality of fiber reinforced layer, wherein The cords intersect each other, and the angle of the cord with respect to the tire circumferential direction is 20 degrees or more and 70 degrees or less.

The plurality of fiber reinforcing layers are provided between the carcass plies on the winding side of the carcass layer corresponding to at least the bead core closest to the equatorial plane of the tire among the plurality of pairs of bead cores in the cross section in the tire meridian direction. Is preferable.

The carcass ply adjacent to the plurality of fiber reinforcing layers includes a cord, and the cord of the carcass ply preferably has an angle of 25 degrees or more and 45 degrees or less with respect to the tire circumferential direction.

It is preferable that one end of the plurality of fiber reinforcing layers is located outside the tire radial direction with respect to a position 0.9 times the height of the rim flange in the cross section in the tire meridian direction.

The other end of the fiber reinforcing layer is located outside the tire radial direction with respect to the position of the end portion of the bead core corresponding to the carcass layer provided with the fiber reinforcing layer in the tire meridional direction. It is preferable to do so.

The thickness of the cord contained in the fiber reinforced layer is preferably equal to or less than the thickness of the cord of the carcass ply adjacent to the fiber reinforced layer.
In order to solve the above-mentioned problems and achieve the object, the pneumatic bias tire according to another aspect of the present invention includes a plurality of pairs of bead cores and a plurality of carcass layers provided corresponding to each of the plurality of pairs of bead cores. And a belt layer provided on the outer side of the carcass layer in the tire radial direction, each of the plurality of carcass layers is formed by laminating a plurality of carcass plies, and any one of the plurality of carcass plies. It has a plurality of laminated fiber reinforcing layers extending adjacent to each other between the carcass plies, and the plurality of fiber reinforcing layers are 0.8 times the height of the rim flange in the cross section in the tire meridional direction. It is provided between the position and the position 1.5 times the height of the rim flange, and in the cross section in the tire meridional direction, from one end on the outer side in the tire width direction where the fiber reinforcing layer extends to the other end on the inner side in the tire width direction. One end of the belt is inside the tire radial direction from the end of the outermost belt in the tire width direction among the belts constituting the belt layer, and each of the plurality of fiber reinforcing layers includes a cord and is described above. The fiber reinforcing layers of the above have different angles with respect to the tire circumferential direction of the cords, the cords intersect each other in the stacking direction, and the angle of the cords with respect to the tire circumferential direction is 70 degrees or more and 80 degrees or less.

According to the pneumatic bias tire according to the present invention, by arranging the reinforcing layer at an appropriate position, the durability can be improved without increasing the number of carcass.

FIG. 1 is a cross-sectional view of the pneumatic bias tire according to the present embodiment in the meridian direction. FIG. 2 is an enlarged view showing a bead portion of the pneumatic bias tire of FIG. 1. FIG. 3 is a diagram showing an example of the range in which the fiber reinforcing layer is provided. FIG. 4 is a diagram showing an example in which a plurality of fiber reinforcing layers are provided. FIG. 5 is a diagram illustrating the position of the inner end portion of the fiber reinforced layer in the tire width direction. FIG. 6 is a diagram illustrating the position of the outer end portion of the fiber reinforced layer in the tire width direction. FIG. 7 is a diagram illustrating an intersecting state of cords of a plurality of fiber reinforcing layers. FIG. 8 is an enlarged view of a bead portion for another example of a pneumatic bias tire. FIG. 9 is an enlarged view showing a bead portion of a conventional pneumatic bias tire.

Hereinafter, embodiments of the pneumatic bias tire according to the present invention will be described in detail with reference to the drawings. This embodiment does not limit the invention. In addition, the components of this embodiment include those that can be easily replaced by those skilled in the art, or those that are substantially the same. The plurality of modifications described in this embodiment can be arbitrarily combined within a range self-evident by those skilled in the art. In the description of each of the following figures, the same or equivalent components as those of the other figures are designated by the same reference numerals, and the description thereof will be simplified or omitted.

The pneumatic bias tire according to the embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of the pneumatic bias tire according to the present embodiment in the meridian direction. FIG. 1 shows a cross-sectional view in the tire radial direction. Further, FIG. 1 shows a pneumatic bias tire for a vehicle or a loader used in a port or the like as an example of a pneumatic bias tire. FIG. 2 is an enlarged view showing a bead portion of the pneumatic bias tire of FIG. 1.

In FIG. 1, the cross section in the tire meridian direction refers to a cross section when a tire is cut on a plane including a tire rotation axis (not shown). Further, the symbol CL is a tire equatorial plane, and refers to a plane that passes through the center point of the tire in the tire rotation axis direction and is perpendicular to the tire rotation axis. Further, the tire radial direction means a direction perpendicular to the tire rotation axis. The tire width direction means a direction parallel to the tire rotation axis, and the tire circumferential direction means a direction around the tire rotation axis.

In FIG. 1, the pneumatic bias tire 1 of the present embodiment has an annular structure centered on a tire rotation axis. The pneumatic bias tire 1 (hereinafter, appropriately referred to as a bias tire 1) has a plurality of bead cores 3a and 3b embedded in a pair of left and right bead portions 2 and 2, respectively (two in FIG. 1). The bead core 3a is the innermost bead core (hereinafter, appropriately referred to as the innermost bead core) closest to the tire equatorial plane CL. The bias tire 1 has bead fillers 4a and 4b corresponding to the bead cores 3a and 3b. The bias tire 1 has carcass layers 10a and 10b corresponding to the bead cores 3a and 3b.

In FIG. 1, the specified rim 30 is shown by a broken line. The bias tire 1 shown in FIG. 1 shows a shape in a state where the rim is assembled. When the bias tire 1 is not rim-assembled with respect to the rim 30 (not shown), the position of the bead toe 50 is inside the tire radial direction from the position shown in the drawing. When the bias tire 1 is rim-assembled with respect to the rim 30, as shown in FIG. 1, the end faces of the bead portions 2 and 2 on the inner side in the tire radial direction are in contact with the fitting surface of the rim 30. .. The bead toe 50 is the end of the bead portions 2 and 2 closest to the tire equatorial plane CL.

The specified rim means the "applicable rim" specified in JATTA, the "Design Rim" specified in TRA, or the "Measuring Rim" specified in ETRTO. The specified internal pressure means the "maximum air pressure" specified in JATTA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified in TRA, or "INFLATION PRESSURES" specified in ETRTO. The specified load means the "maximum load capacity" specified in JATTA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified in TRA, or the "LOAD CAPACITY" specified in ETRTO.

The pair of bead cores 3a and 3b are annular members formed by bundling a plurality of bead wires, and form the cores of the left and right bead portions 2 and 2. The bead fillers 4a and 4b are rubber materials arranged outside the pair of bead cores 3a and 3b in the tire radial direction. The bead fillers 4a and 4b form a bead portion together with the pair of bead cores 3a and 3b. In the cross section in the tire meridian direction, the thickness of the bead fillers 4a and 4b in the tire width direction gradually decreases from the positions of the corresponding bead cores 3a and 3b toward the outside in the tire radial direction.

The bias tire 1 has a plurality of carcass layers 10a and 10b provided corresponding to each of a plurality of pairs of bead cores 3a and 3b. The plurality of carcass layers 10a and 10b are provided so that the cord directions intersect each other between the layers. The carcass layers 10a and 10b are wound up from the inside to the outside in the tire width direction so that the cord directions intersect each other between adjacent pairs. The carcass layers 10a and 10b are respectively bridged between the pair of bead cores. At the same time, the carcass layers 10a and 10b are locked by winding the ends of the carcass layers 10a and 10b while wrapping the bead cores 3a and 3b and the bead fillers 4a and 4b corresponding thereto.

Each of the plurality of carcass layers 10a and 10b is formed by laminating a plurality of carcass plies. In FIGS. 1 and 2, the number of carcass plies contained in each of the carcass layers 10a and 10b is four. The carcass ply of the carcass layer is formed by coating a plurality of carcass cords made of steel or an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) with coated rubber and rolling them. As the carcass ply of the carcass layer, a plurality of the same carcass ply may be used, or different carcass plies may be mixed.

The carcass ply of the carcass layers 10a and 10b is formed by coating a plurality of carcass cords made of steel or an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) with a coated rubber and rolling them. As the carcass ply of the carcass layers 10a and 10b, a plurality of the same carcass ply may be used, or different carcass plies may be mixed. For example, one outermost carcass ply of a plurality of rewound carcass plies may have a different degree of vulcanization from other carcass plies. As described above, the bias tire 1 has two or more carcass layers.

Further, the bias tire 1 has belts 8 and 8a which are fiber reinforcing layers on the outer peripheral side of the carcass layer in the tread portion 5. The belts 8 and 8a form a belt layer. An inner liner 9 is formed along the carcass layer 10a on the inner side of the bias tire 1.

The tread rubber 15 is arranged on the outer periphery in the tire radial direction with respect to the carcass layers 10a and 10b and the belts 8 and 8a to form the tread portion 5 of the tire. The pair of sidewall rubbers 17 and 17 are arranged on the outer sides of the carcass layers 10a and 10b in the tire width direction, respectively, to form the left and right sidewall portions 7. The pair of rim cushion rubbers 20 and 20 are arranged inside the rewinding portions of the left and right bead cores 3a and 3b and the carcass layers 10a and 10b in the tire radial direction, respectively, and the contact surfaces of the left and right bead portions 2 with respect to the flange 30F of the rim 30. To configure. The bias tire 1 may not have the rim cushion rubber 20.

The bias tire 1 has a groove 11 in the tread portion 5. In FIG. 1, the groove bottom of the groove 11 is shown by a broken line. Both ends of the tread portion 5 in the tire width direction are formed as shoulder portions 6, and sidewall portions 7 are arranged from the shoulder portion 6 to a predetermined position inside in the tire radial direction. The sidewall portions 7 are arranged at two locations on both sides of the bias tire 1 in the tire width direction. The sidewall portions 7 and 7 have a pair of sidewall rubbers 17 and 17.

[Required range for installing fiber reinforced concrete]
The bias tire 1 has a fiber reinforcing layer 100 between the carcass plies forming the carcass layer 10a. As shown in FIG. 2, the fiber reinforcing layer 100 extends adjacently between the carcass ply. The fiber reinforcing layer 100 includes a cord. The fiber reinforcing layer 100 is formed by coating a plurality of cords made of steel or an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) with coated rubber and rolling them. The fiber reinforcing layer 100 is in a range from a position 0.8 times the rim flange height FH to a position 1.5 times the rim flange height FH in the cross section in the tire meridional direction (hereinafter, referred to as an essential range). At least provided in between. As long as the range includes all of the essential ranges, the fiber reinforcing layer 100 may be provided between any of the carcass plies, and the carcass layer 10b is farther from the tire equatorial plane CL than the carcass layer 10a. It may be provided between the equator plies.

Breakage of the carcass layer 10a near the intersection of the vertical line H lowered toward the inner liner 9 from the rim separation point 31 which is the outermost point in the tire radial direction where the rim flange 30F contacts the sidewall rubber 17 and the inner liner 9. May occur. Since this area is where the tension of the carcass layer 10a becomes high, it is possible to effectively improve the strength without increasing the number of carcass plies by providing the fiber reinforcing layer 100 in an indispensable range including this area. can.

It is not necessary to increase the number of carcass plies in order to suppress the CBU near the intersection of the vertical line H and the inner liner 9 shown in FIG. 2, and it is the outermost of the belts 8 and 8a constituting the belt layer in the tire width direction. It is sufficient that the end portion of the fiber reinforcing layer 100 is inside the end portion of the belt 8 in the tire radial direction. Even if the fiber reinforcing layer 100 is extended further, the effect is small, and the cost for the weight of the tire as a product increases more than necessary.

[Positional relationship between fiber reinforced layer and bead core]
Further, since the fiber reinforcing layer 100 may be provided at least in an essential range, the bead core 3a may be involved and extended. FIG. 3 is a diagram showing an example of the range in which the fiber reinforcing layer is provided. As shown in FIG. 3, the fiber reinforced layer 100a of this example extends inward in the tire radial direction from an essential range, extends outward in the tire width direction, and winds the bead core 3a. After the bead core 3a is wound, the fiber reinforcing layer 100a extends so as to be wound outward in the tire radial direction. Here, the direction from the outside in the radial direction of the tire toward the bead core 3a or the like is referred to as a winding direction or a winding direction. The direction from the bead core 3a to the outside in the tire radial direction after the bead core 3a or the like is wound is called a winding direction or winding.

That is, as shown in FIG. 3, in the cross section in the tire meridian direction, the end portion T1 on the outer side of the fiber reinforcing layer 100a in the tire width direction is the position where the bead core 3a of the carcass layer provided with the fiber reinforcing layer is wound up. It is inside the tire radial direction from the position of the turn-up height (Turn Up Height, hereinafter referred to as TUH). By suppressing the position of the end portion T1 of the fiber reinforcing layer 100a on the outer side in the tire width direction to the inner side in the tire radial direction with respect to the position of the TUH, separation at the end portion of the turn-up position can be prevented.

By involving the bead core 3a in the fiber reinforcing layer 100a, in addition to the strong increase in the bead portion 2, the movement of the surface (innermost surface) of the bead portion 2 closest to the tire equatorial plane CL can be suppressed, and the tension applied to the bead portion 2 can be suppressed. Can be reduced.

The fiber reinforced layer 100a is formed between the carcass plies on the winding side of the carcass layer 10a corresponding to at least the bead core 3a closest to the tire equatorial plane CL among the plurality of pairs of bead cores 3a and 3b in the cross section in the tire meridian direction. It is preferable that the tire is provided in. That is, it is preferable that the fiber reinforcing layer 100a is inserted at least between the winding-side carcass plies of the innermost bead 3a. By involving the bead core 3a in the fiber reinforcing layer 100a, in addition to the strong increase in the bead portion 2, the movement of the surface (innermost surface) of the bead portion 2 closest to the tire equatorial surface CL can be more effectively suppressed, and the bead can be suppressed. The tension applied to the part 2 can be reduced.

[Number of fiber reinforced layers, etc.]
It is preferable to provide a plurality of fiber reinforcing layers. In that case, it is preferable to provide the plurality of fiber reinforcing layers in a laminated manner. FIG. 4 is a diagram showing an example in which a plurality of fiber reinforcing layers are provided. As shown in FIG. 4, in this example, the plurality of fiber reinforcing layers 100b and 100c are laminated adjacent to each other. The plurality of fiber reinforcing layers 100b and 100c extend adjacent to the carcass ply between the carcass plies in a laminated state. The range in which the plurality of fiber reinforcing layers 100b and 100c of this example are provided includes all the essential ranges shown in FIG.

Also in this example, the outer end portion T5 of the fiber reinforcing layer 100b in the tire width direction exists at a position in front of the end portions T7 and T8 of the adjacent carcass ply. Similarly, the outer end portion T6 of the fiber reinforcing layer 100c in the tire width direction exists at a position in front of the end portions T7 and T8 of the adjacent carcass ply.

When a plurality of fiber reinforcing layers are provided, they may be provided between the carcass plies of the carcass layer 10a and between the carcass plies of the carcass layer 10b, respectively.

[Position of the end of the fiber reinforced layer]
In FIG. 3, the outer end portion T1 of the fiber reinforcing layer 100a in the tire width direction exists at a position in front of the positions of the end portions T2 and T3 of the carcass ply adjacent to the fiber reinforcing layer 100a, that is, TUH. The inner end portion T4 of the fiber reinforcing layer 100a in the tire width direction extends outward in the tire radial direction along the adjacent carcass ply.
FIG. 5 is a diagram illustrating the position of the inner end portion of the fiber reinforced layer in the tire width direction. FIG. 5 is a diagram illustrating the positions of the inner ends of the fiber reinforced layer in the tire width direction, that is, the end T4 in FIG. 3, the end T9 in FIG. 4, and the end T10. The end portion T4 of the fiber reinforcing layer 100a may be present at any position within the range RI shown in FIG. That is, the end portion T4 on the inner side in the tire width direction is the tire from the position of the vertical line H1 drawn from the end portion 8T of the belt 8 on the outermost side in the tire width direction with respect to the inner liner 9 among the belts 8 and 8a constituting the belt layer. It suffices if it exists inside in the radial direction. Further, the end portion T4 on the inner side in the tire width direction may be located on the outer side in the tire radial direction from the position H2 which is 0.9 times the rim flange height FH. Since the tension is particularly strong outside the tire radial direction from the separation point 31 of the flange 30F of the rim 30, the fiber reinforcing layer 100a is up to 0.9 times the height of the flange 30F of the rim 30 which is the separation point position from the rim 30. Need to be postponed.

Further, the end portion T9 of the fiber reinforced layer 100b in FIG. 4 on the inner side in the tire width direction may be present at any position within the range RI shown in FIG. Similarly, the end T10 on the inner side of the fiber reinforced layer 100c in FIG. 4 in the tire width direction may be present at any position within the range RI shown in FIG.

That is, the fiber reinforcing layer 100a covers at least from a position 0.8 times the rim flange height FH shown in FIG. 2 to a position 1.5 times the rim flange height FH in the cross section in the tire meridional direction. As shown in FIG. 5, the end (one end) of the fiber reinforcing layer 100a on the tire width direction is outside the end of the belt 8 in the tire width direction, and the end (the other end) on the opposite side of the fiber reinforcing layer 100a. ) Exists at the end of the adjacent carcass ply, that is, at a position in front of the position of TUH.

In this example, two fiber reinforcing layers are provided, but three or more fiber reinforcing layers may be provided. Even when three or more fiber reinforced layers are provided, the range in which the fiber reinforced layers are provided needs to include all the essential ranges shown in FIG. Further, the position of the inner end portion of the fiber reinforced layer in the tire width direction may be located at any position within the range RI shown in FIG. The outer end portion of the fiber reinforced layer in the tire width direction may be present at a position in front of the position of the end portion of the adjacent carcass ply.

In FIG. 5, the broken line H0 is a broken line parallel to the tire rotation axis, and the SDH (Side Height) is the maximum protruding position of the bias tire 1 in the tire width direction. The position of SDH is included within the range RI shown in FIG.

Further, the outer end portion of the fiber reinforced layer in the tire width direction will be described with reference to FIG. FIG. 6 is a diagram illustrating the position of the outer end portion of the fiber reinforced layer in the tire width direction. As shown in FIG. 6, the outer end portion T5 of the fiber reinforced layer 100b in the tire width direction and the outer end portion T6 of the fiber reinforced layer 100c in the tire width direction have tire diameters larger than the position H3 of the end portion of the adjacent carcass ply. It is preferably located inside the direction. Further, the ends T5 and T6 are preferably located outside the tire radial direction from the position H4 of the bead core 3a corresponding to the carcass layer 10a provided with the fiber reinforcing layer 100b. By locating the outer end portion in the tire width direction on the outer side in the tire radial direction from the position H4 of the outer end portion in the tire radial direction of the bead core 3a, the fiber reinforcing layers 100b and 100c are firmly fixed by the bead core 3a and the carcass. It can be integrated with the layer 10a to effectively exert a reinforcing effect. Therefore, the ends T5 and T6 need only exist at any position within the range RO between the position H3 and the position H4.

[Cross of cords of fiber reinforced layer, etc.]
By the way, each of the plurality of fiber reinforcing layers 100b and 100c contains a cord. The fiber reinforcing layers 100b and 100c are formed by coating a plurality of cords made of steel or an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) with coated rubber and rolling them. It is preferable that the plurality of laminated fiber reinforcing layers 100b and 100c are provided so that the cords have different angles with respect to the tire circumferential direction and the cords intersect each other in the laminated direction.

FIG. 7 is a diagram illustrating an intersecting state of cords of a plurality of fiber reinforcing layers 100b and 100c. As shown in FIG. 7, the fiber reinforcing layers 100b and 100c are provided between the carcass ply 10a1 and 10a2. The fiber reinforcing layer 100b and the fiber reinforcing layer 100c are laminated. The angle of the cord of the fiber reinforced layer 100b with respect to the tire circumferential direction and the angle of the cord of the fiber reinforced layer 100c with respect to the tire circumferential direction are different. Therefore, the cord of the fiber reinforcing layer 100b and the cord of the fiber reinforcing layer 100c intersect in the stacking direction of the fiber reinforcing layers 100b and 100c. By installing two or more fiber reinforced layers so that the cords intersect at an angle, it is possible to create a so-called tag effect that increases the force for tightening the pneumatic bias tire to the rim. As a result, the fiber reinforcing layer can exert the effect of reinforcing the pneumatic bias tire and suppress CBU.

Further, the fiber reinforcing layers 100b and 100c preferably have an angle of the cord with respect to the tire circumferential direction of 20 degrees or more and 70 degrees or less. That is, the angle θ1 of the fiber reinforcing layer 100b with respect to the tire circumferential direction is 20 degrees or more and 70 degrees or less, and the angle θ2 of the fiber reinforcing layer 100c with respect to the tire circumferential direction is 20 degrees or more and 70 degrees or less. Is preferable. In FIG. 7, the angle θ1 is a clockwise angle with respect to the tire circumferential direction, and the counterclockwise angle with respect to the tire circumferential direction is an angle θ2, but conversely, the angle θ1 is with respect to the tire circumferential direction. The counterclockwise angle and angle θ2 may be the clockwise angle with respect to the tire circumferential direction. In the following description, the clockwise angle is defined as the + direction (plus direction) angle, and the counterclockwise angle is defined as the − direction (minus direction) angle.

By setting the angles θ1 and θ2 both within the range of 20 degrees or more and 70 degrees or less, the tag effect is exhibited until the reinforcing effect can be expected. If the angles θ1 and θ2 are out of this range, the cord angle is too close in the tire circumferential direction or the tire width direction. Therefore, if it is out of this range, sufficient rigidity cannot be obtained for suppressing deflection. In addition, if it is out of this range, the tag effect cannot be fully exerted.

If the cord of the fiber reinforcing layer 100b and the cord of the fiber reinforcing layer 100c intersect in the stacking direction of the fiber reinforcing layers 100b and 100c, the angle θ1 and the angle θ2 may be different. If the cords intersect, a so-called tag effect can be produced even if the angles of the cords are different, and the pneumatic bias tire can be reinforced to suppress CBU.

The cord of the carcass ply adjacent to the fiber reinforcing layers 100b and 100c preferably has an angle of 25 degrees or more and 45 degrees or less with respect to the tire circumferential direction. It should be noted that the angles of the cords do not have to intersect with the fiber reinforcing layers 100b and 100c and the adjacent carcass ply, but they may intersect.

The thickness of the cord contained in the fiber reinforcing layers 100b and 100c is preferably equal to or less than the thickness of the cord of the carcass ply adjacent to the fiber reinforcing layers 100b and 100c. In order to suppress the separation due to the difference in rigidity with the adjacent carcass ply while having a sufficient reinforcing effect, the cords contained in the fiber reinforcing layers 100b and 100c have the same thickness as the cords of the adjacent carcass plies. The following code is desirable. If the cords included in the fiber reinforcing layers 100b and 100c and the cords of the adjacent carcass ply have the same thickness, the productivity of the tire can be improved.

[Other examples]
FIG. 8 is an enlarged view of a bead portion for another example of a pneumatic bias tire. As described above, the fiber reinforcing layer may be provided at least in an essential range. Therefore, as shown in FIG. 8, if the ends T11 and T12 of the fiber reinforcing layers 100d and 100e are located outside the tire radial direction from the position 1.5 times the rim flange height FH, the fiber reinforcing layers are reinforced. Even if the ends T15 and T16 of the layers 100d and 100e are located inside the tire radial direction from the position 0.8 times the rim flange height FH, the condition that they are provided in the essential range is satisfied. The ends T11 and T12 are located in front of the ends T13 and T14 of the adjacent carcass ply.

However, as described with reference to FIGS. 3 and 4, when the fiber reinforced layer extends by winding the bead core, the fiber reinforced layer is provided between the carcass plies on the winding side of the innermost bead core 3a. It is preferable that the fiber is used. By providing the fiber reinforcing layer at this position, the movement of the surface (innermost surface) closest to the tire equatorial surface CL can be suppressed more effectively, and the tension applied to the bead portion 2 can be reduced.

[Action under high load]
In FIG. 2, when a high load is applied, stresses of a force acting in the tire width direction and a force acting outward in the tire radial direction are applied to the bias tire 1 in the direction of arrow Y1. If the bias tire 1 does not have the fiber reinforced layer 100 and the rigidity on the inner surface side from the bead toe 50 is insufficient with respect to the load, the bead toe 50 may be lifted from the rim 30 and excessive distortion may occur. When such excessive strain is generated, CBU is generated in the carcass layer 10a corresponding to the bead core 3a, and separation is generated in the rubber in the vicinity of the carcass layer 10a. On the other hand, the bias tire 1 of the present embodiment has the fiber reinforcing layer 100, and the fiber reinforcing layer 100 is provided in an indispensable range in which the tension of the carcass layer 10a becomes high. Therefore, the strength can be effectively improved without increasing the number of carcass plies, and the occurrence of CBU and separation can be suppressed. The configuration of FIGS. 3, 4, 5, and 7 is the same as the above action, and the strength can be effectively improved without increasing the number of carcass plies, and the occurrence of CBU and separation can be suppressed. ..

[summary]
In order to prevent CBU and separation due to excessive tension of the inner surface side carcass layer closest to the equator surface of the tire, it is conceivable to increase the number of carcass so as to withstand excessive tension as a general measure. However, this measure leads to poor productivity, increased cost, and increased weight. According to the bias tire of the present embodiment, the movement of the bead core can be suppressed by providing a fiber reinforcing layer in an indispensable range adjacent to the carcass plies, and the durability performance can be improved without increasing the number of carcasses. can.

The durability performance of the bead portion 2 of the bias tire 1 of the present embodiment was evaluated. In this embodiment, 29.5-25 L22 size tires are mounted on the specified rim, and the actual vehicle is run under 650 kPa (TRa standard: 350 kPa) and 150% load conditions until the bead portion 2 fails. Durability was evaluated based on the running time. The longer the time, the higher the durability performance.

Further, for the bias tire 1 of the present embodiment, the reciprocal (weight / cost) of the cost value with respect to the weight of the tire was evaluated as a cost index. The larger the reciprocal value, the higher the cost index (that is, the higher the cost performance).

Further, as a conventional example, a bias tire having an increased number of carcass plies was prepared without providing a fiber reinforcing layer. FIG. 9 is an enlarged view showing a bead portion of a conventional pneumatic bias tire. In the conventional pneumatic bias tire shown in FIG. 9, the carcass ply of the carcass layer 10a corresponding to the innermost bead core 3a is increased, and the number of the carcass ply is increased to five.

Further, the pneumatic bias tires of Comparative Example 1 and Comparative Example 2 were prepared. The pneumatic bias tire of Comparative Example 1 had one fiber reinforced layer, and the fiber reinforced layer was not provided in an essential range. The pneumatic bias tire of Comparative Example 2 has one fiber reinforced layer, and the fiber reinforced layer is provided in a range including all the essential ranges. In both the pneumatic bias tires of Comparative Example 1 and Comparative Example 2, it was assumed that one end of the fiber reinforced layer inside in the tire width direction intersects the tire equatorial plane CL, that is, the end is located at the position of the crown center. .. In both the pneumatic bias tires of Comparative Example 1 and Comparative Example 2, the direction of the cord of the fiber reinforced layer is +80 degrees with respect to the tire circumferential direction, and the fiber reinforced layer does not involve the bead core and has a tire diameter larger than that of the bead core. It is assumed that the end is on the outside in the direction. In the pneumatic bias tires of Comparative Example 1 and Comparative Example 2, the thickness of the cord of the fiber reinforced layer was made thicker than the cord of the adjacent carcass ply.

As shown in Tables 1 and 2, the bias tires of Examples 1 to 13 include a fiber reinforced layer, and the range in which the fiber reinforced layer is provided includes all the essential ranges. Further, in the bias tires of Examples 1, 2, and 5 to 11, the position of the inner end portion of the fiber reinforced layer in the tire width direction is the position of the broken line H0 passing through the SDH. In the bias tires of Examples 3 and 4, the position of the inner end portion of the fiber reinforced layer in the tire width direction is the position of the end portion of the belt 8.

As shown in Tables 1 and 2, the bias tires of Examples 1 to 3 are provided with only one fiber reinforcing layer, and the bias tires of Examples 4 to 13 are provided. It was assumed that there were two fiber reinforced layers. In the bias tires of Examples 6 to 13, the cords of the two provided fiber reinforcing layers intersect with each other. In each of the pneumatic bias tires of Examples 1 to 3, the direction of the cord of the fiber reinforcing layer is +80 degrees with respect to the tire circumferential direction, and the bias tires of Examples 4 to 13 have two fibers. The direction of the cord of the reinforcing layer was ± 80 degrees, ± 70 degrees, ± 45 degrees, and ± 20 degrees with respect to the tire circumferential direction.

As shown in Tables 1 and 2, in the bias tires of Examples 1 to 10, the fiber reinforcing layer does not involve the bead core and has an end portion on the outer side in the tire radial direction from the bead core. The bias tire of Example 11 has a fiber reinforced layer involving a bead core on the innermost surface, the bias tire of Example 12 has a fiber reinforcing layer involving a bead core other than the innermost surface, and the bias of Example 13. The tire was assumed to have a fiber reinforced layer around which a bead core was wound and further wound up to the position of TUH of the carcass layer and extended. In the pneumatic bias tire of Example 1, the thickness of the cord of the fiber reinforced layer is thicker than the cord of the adjacent carcass ply, and the bias tires of Examples 2 to 9 and 11 to 13 are , The thickness of the cord of the fiber reinforced layer is the same as the cord of the adjacent carcass ply. It was thin.

According to Examples 1 to 13 of Tables 1 and 2, good results were obtained when the fiber reinforced layer was included and the range in which the fiber reinforced layer was provided included all the essential ranges. According to Examples 1 to 13 of Tables 1 and 2, it is good when the inner end portion of the fiber reinforced layer in the tire width direction is inside the tire radial direction from the end portion of the outermost belt in the tire width direction. Results were obtained.

Further, according to Examples 1 to 13 of Tables 1 and 2, when a plurality of fiber reinforcing layers are included and the cords of the fiber reinforcing layers intersect with each other, the angle of the cords with respect to the tire circumferential direction is 20 degrees or more and 70 degrees. Good results were obtained when: Further, according to Examples 1 to 13 of Tables 1 and 2, good results were obtained when the fiber reinforcing layer encloses the bead core. According to Examples 1 to 13 of Tables 1 and 2, good results were obtained when the thickness of the cord of the fiber reinforced layer was less than or equal to the cord of the adjacent carcass ply.

1 Pneumatic bias tire 2 Bead part 3a, 3b Bead core 4a, 4b Bead filler 5 Tread part 6 Shoulder part 7 Side wall part 8, 8a Belt 9 Inner liner 10a, 10b Carcus layer 10a1, 10a2 Carcus ply 15 Tread rubber 17 Side wall Rubber 20 Rim Cushion Rubber 30 Rim 30F Flange 50 Bead toe 100, 100a, 100b, 100c, 100d, 100e Fiber reinforcement layer

Claims (7)

A plurality of pairs of bead cores, a plurality of carcass layers provided corresponding to each of the plurality of pairs of bead cores, and a belt layer provided on the outer side of the carcass layer in the tire radial direction are included.
Each of the plurality of carcass layers is formed by laminating a plurality of carcass plies.
Among the plurality of carcass plies, a plurality of laminated fiber reinforcing layers extending adjacent to each other among the plurality of carcass plies are provided.
Wherein the plurality of fiber reinforced layers in the cross section of the tire meridian direction, set between 0.8 times the position of the rim flange height up to 1.5 times the position of the rim flange height vignetting,
Further, the fiber reinforcing layer is a tire in which the bead core corresponding to the carcass layer provided with the fiber reinforcing layer is wound from the inside in the tire width direction in the cross section in the tire meridional direction, and then the bead core is wound up and extended. From one end on the outer side in the width direction to the other end on the inner side in the tire width direction, which is the end before winding , the other end is from the end of the outermost belt in the tire width direction among the belts constituting the belt layer. is inside the tire radial direction, the one end, Ri position near the tire radial direction inner side from the end portion of the carcass ply adjacent to the fiber-reinforced layer,
Each of the plurality of fiber reinforcing layers contains a cord and contains a cord.
The plurality of fiber reinforcing layers have different angles with respect to the tire circumferential direction of the cords, and the cords intersect each other in the stacking direction of the plurality of fiber reinforcing layers.
A pneumatic bias tire in which the angle of the cord with respect to the tire circumferential direction is 20 degrees or more and 70 degrees or less. The plurality of fiber reinforcing layers are provided between the carcass plies on the winding side of the carcass layer corresponding to at least the bead core closest to the equatorial plane of the tire among the plurality of pairs of bead cores in the cross section in the tire meridian direction. The pneumatic bias tire according to claim 1. The pneumatic bias tire according to claim 1 or 2 , wherein the carcass ply adjacent to the plurality of fiber reinforcing layers includes a cord, and the cord of the carcass ply has an angle of 25 degrees or more and 45 degrees or less with respect to the tire circumferential direction. .. One of claims 1 to 3 , wherein one end of the plurality of fiber reinforcing layers is located outside the tire radial direction from a position 0.9 times the height of the rim flange in the cross section in the tire meridional direction. Pneumatic bias tires described in. The other end of the fiber reinforcing layer is located outside the tire radial direction with respect to the position of the end portion of the bead core corresponding to the carcass layer provided with the fiber reinforcing layer in the tire meridional direction. The pneumatic bias tire according to any one of claims 1 to 4. The pneumatic bias tire according to any one of claims 1 to 5 , wherein the thickness of the cord included in the fiber reinforcing layer is equal to or less than the thickness of the cord of the carcass ply adjacent to the fiber reinforcing layer. .. A plurality of pairs of bead cores, a plurality of carcass layers provided corresponding to each of the plurality of pairs of bead cores, and a belt layer provided on the outer side of the carcass layer in the tire radial direction are included.
Each of the plurality of carcass layers is formed by laminating a plurality of carcass plies.
Among the plurality of carcass plies, a plurality of laminated fiber reinforcing layers extending adjacent to each other among the plurality of carcass plies are provided.
The plurality of fiber reinforcing layers are provided between a position 0.8 times the rim flange height and a position 1.5 times the rim flange height in the cross section in the tire meridional direction.
In the cross section in the tire meridional direction, from one end on the outer side in the tire width direction to which the fiber reinforcing layer extends to the other end on the inner side in the tire width direction, the one end is the most tire width direction among the belts constituting the belt layer. Located inside the tire radial direction from the end of the outer belt,
Each of the plurality of fiber reinforcing layers contains a cord and contains a cord.
The plurality of fiber reinforcing layers have different angles of the cords with respect to the tire circumferential direction, and the cords intersect each other in the stacking direction.
The angle of the cord with respect to the tire circumferential direction is 70 degrees or more and 80 degrees or less.
Pneumatic bias tire.

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