JP3093812B2 - Band layer molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a band layer capable of effectively suppressing separation at both ends of a belt layer, thereby improving the high-speed durability of a tire and improving its productivity. It relates to a molding method.

[0002]

2. Description of the Related Art With the improvement of road networks and high performance of vehicles, radial tires having a belt layer made of a steel cord arranged outside a radially arranged carcass are often used as tires suitable for high-speed running. . However, in this case, both ends of the belt layer may be lifted due to centrifugal force accompanying rotation of the tire during high-speed running, and peeling may occur between the belt and surrounding rubber. In particular, such lifting is likely to occur sequentially from the outermost layer of the belt ply, and in the case where a cut-end ply is used as the belt layer, the peeling is further promoted in combination with poor adhesion to rubber at the cut end. You. Therefore, in recent years, in order to prevent the rubber separation and improve the high-speed durability, for example, as shown in FIG. 10A, both ends of a belt layer B are covered with a band layer C folded in a U-shape. I have. In this case, since the belt layer B is sandwiched between the lower piece C1 along the lower surface of the belt layer B and the upper piece C2 along the upper surface, the movement can be effectively suppressed, and the cut end is covered and the adhesiveness is improved. Can be improved.

[0003]

However, as shown in FIG. 10b, such a band layer C generally has a band cord made of organic fibers arranged at an angle of 30 degrees or more with respect to the tire equator. It is formed by winding the belt-shaped body D in an annular shape, and then turning the outer end Ee of the annular body E inward in the tire axial direction.

[0004] Therefore, in this case, the diameter is temporarily increased at the time of folding back, so that the tightening force on the belt layer B is insufficient, and the restraining force on the belt end is lacking. In particular, in an ultra-high speed region of 200 km / h or more, The effect of improving the durability performance cannot be exhibited. Moreover, in the case of this structure, the band-shaped body D at the time of winding is used.
Since the joints F are formed at the front and rear ends of the joints, the circumferential rigidity is non-uniformly reduced, and the restraining force is reduced. On the other hand, a large strain is induced in the joints F and a starting point of damage is generated. Easy to make. Therefore, in recent years, it has been strongly desired to form such a U-shaped band layer in an endless shape by spirally winding a band cord, to achieve uniform circumferential rigidity, and to increase the binding force to the belt end. For that purpose, a new band forming method is required.

That is, the present invention provides a band layer forming method capable of forming a U-shaped band layer formed by spirally winding a band cord, improving the high-speed durability of a tire and improving the productivity thereof. It is an object.

[0006]

SUMMARY OF THE INVENTION The present invention provides a belt layer comprising at least two belt plies disposed radially outside a radially arranged carcass and inside a tread portion.
And wherein the lower piece is along and outer edges in the tire radial direction inner surface of the belt plies than the outer end of the belt ply, continuous to the outer edge of the bottom piece, comprising a band layer having an upper piece along the outer surface of said belt ply Of the band of the radial tire
In a molding method, one end of a band-shaped band cord body in which one to several organic fiber cords are aligned in parallel with each other is positioned on the outer peripheral surface of a drum for forming a tread reinforcing layer inward in the tire axial direction. first step of forming the lower piece by continuously winding in the tire axial direction outer side in a spiral shape, the first
On the outer surface of the resultant lower piece by step, so as to project axially outward the outer edge of the lower piece beyond the outer end of the belt ply, wound child a sheet-like belt strip
It said upper piece is formed by winding toward the second step, and axially inward of consecutive to and spirally and the other end of the band cord body forming the belt ply by a, A band layer forming method comprising a third step of forming a U-shaped band layer enclosing an outer end portion of the belt ply with an upper piece and a lower piece .

[0007]

The method of forming a band layer configured as described above is divided into a spiral winding step for forming the lower piece of the band layer and a spiral winding step for forming the upper piece of the band layer.
A step for forming a belt ply by winding a belt piece is provided between these steps.

In addition, since the band-shaped band cord body forms a lower piece by spirally winding one end of the band cord body inward in the tire axial direction, the other end of the band cord body is a tire. It is located axially outward, so that after the belt ply is formed, the other end can be continuously wound in a spiral shape.

As a result, a U-shaped band layer formed by spirally winding a band cord can be formed conveniently and easily.

In this case, since the lower piece and the upper piece are continuous, the end of the belt ply can be covered, and the adhesiveness with the rubber at the end of the belt ply can be improved.
Further, since the lower piece and the upper piece are each formed of a spirally continuous band cord, there is no occurrence of a conventional joint portion, and the circumferential rigidity can be made uniform. In addition, it has a high tightening force and can hold the belt ply end between the lower piece and the upper piece to restrain it, and the synergistic effect of this effectively suppresses ply end peeling and greatly improves the tire's restraint durability. Can.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for forming a band layer according to the present invention will be described below with reference to the drawings together with a tire having a band layer obtained by the method.

In FIG. 1, a tire 1 includes a pair of bead cores 3, a pair of bead apexes 4, a carcass 2, a tread portion 5, a pair of sidewall portions 6, a belt layer 7,
It has a band layer 8.

The bead core 3 has a bead portion 9 of a tire.
Distributed to. The bead apex 4 is made of a hard rubber that extends from the bead core 3 outward in the tire radial direction and is filled between the main body of the carcass 2 and the folded portion.

The carcass 2 is formed of at least one carcass ply in which carcass cords are arranged at an angle of 75 to 90 degrees with respect to the tire equator, and the bead portion 9 extends from the tread portion 5 to the sidewall portion 6. , The both ends of the toroidal body are bent around the bead core 3 to be locked.

The belt layer 7 includes at least two belt plies disposed radially outside the carcass 2 in the tire radial direction.
In this example, the inner belt ply 7i and the outer belt ply 7o
However, a belt ply of one or two sheets may be interposed between them. Although the figure shows an example in which the inner belt ply 7i has a wider width than the outer belt ply 7o, it may be reversed.
However, if the two sheets have the same width, the in-section bending stiffness changes abruptly at the ends, adversely affecting the durability. Therefore, it is necessary to set the two sheets to at least different widths.

Each of the belt plies 7i and 7o is shown in FIG.
The belt belt 11 is formed by winding a belt-shaped belt-like piece 12 of a blind weave in which the belt cords 11 are arranged at an angle of 10 to 30 degrees with respect to the tire equator in the tire circumferential direction, as schematically shown in FIG. As the cord 11, a high-strength organic fiber cord such as an aromatic polyamide fiber is used in addition to a metal cord such as steel.

At both ends of the belt layer 7,
A substantially U-shaped band layer 8 surrounding the end of the belt layer 7 is provided. As described above, the lifting of the belt layer 7 accompanying the high-speed rotation occurs sequentially from the outermost belt ply in the tire radial direction. Therefore, the band layer 8 needs to cover at least the outer end of the outer belt ply 7o. In this example, the case where the band layer 8 wraps the outer end of both the inner and outer belt plies 7i and 7o will be described. I do.

That is, in this example, the band layer 8 has a lower piece 15 extending along the tire radial inner surface of the inner belt ply 7i, as schematically shown in FIG. Reference numeral 15a protrudes outward in the tire axial direction beyond the outer end ei of the inner belt ply 7i. The outer edge 1 of the lower piece 15
5a, an upper piece 16 extending inward in the tire axial direction along the outer end face and the upper face of the inner belt ply 7i and the outer end face of the outer belt ply 7o and along the upper face of the outer belt ply 7o.
The lower piece 15 and the upper piece 16 form a substantially U-shaped band layer 8 wrapping the outer ends of the inner and outer belt plies 7i, 7o.

The band layer 8 is made of an organic fiber cord 17 substantially parallel to the tire equator. The organic fiber cord 17 is made of a spun yarn of an organic fiber made of nylon 66, nylon 6, aromatic polyamide or the like. , A monofilament yarn, a multifilament single yarn or a fuel yarn. As shown in FIG. 4, one or several of the cords 17 are wound spirally in the circumferential direction of the tire to form the band layer 8. 8
Does not include the conventional joints, and the adverse effects due to the presence of these joints can be completely prevented. In this conventional joint portion, the winding start end and the winding end are merely superimposed, so that it cannot withstand a large circumferential tension and is inferior in the tightening force on the belt layer 7. The use in a high-speed range often causes destruction, and also impairs the uniformity of the tire.

The inner edge 16b of the upper piece 16 of the band layer 8
The distance G1 in the tire axial direction is 0.3 mm of the maximum belt ply width WB of the belt plies wrapped by the band layer 8.
The ratio is preferably 5 to 0.65 times, and when it exceeds 0.65 times, the restraining force on the belt layer 7 becomes insufficient and the lifting prevention effect is inferior. However, conversely, 0.35
When it is smaller than twice, the rigidity of the entire tread becomes excessive and the controllability to the vehicle is impaired, and the steering stability is reduced.

As shown in FIGS. 7A to 7C, the band layer 8 including the upper piece 16 and the lower piece 15 and formed by the spiral winding of the organic fiber cord is used.
A first step of forming the lower piece 15 with the drum 20 by using the band cord body 18 made of 7 and a belt ply 7i, 7o on the outer surface of the lower piece 15 obtained in the first step.
Formed by a third method of forming a band layer of the present invention comprising the step of the second step, further forming a top piece 16 with the remainder of the band cord body 18 formed of the lower piece 15 to form a Can.

As shown in FIG. 5, the band cord body 18 has a long band shape in which one or several organic fiber cords 17 are aligned in parallel with each other and integrated with a coating rubber R. None, when several cords 17 are aligned, the accuracy of pitch P between cords can be increased and the subsequent winding efficiency can be improved. However, the band cord body 18 desirably has an angle of the wound cord 17 with respect to the tire equator not much more than 0 degrees from the viewpoint of tire uniformity. Therefore, the number of cords 17 to be aligned is 15 or less, more preferably. 10 or less.

When the band cord body 18 is composed of one organic fiber cord 17, as shown in FIG. 6, a coating rubber R having a thickness of 0.1 to 0.2 mm is provided around the cord. What adhered can be used.

The drum 20 is a cylindrical drum 20 that can be enlarged and reduced in diameter for forming a tread reinforcing layer 21 including a belt layer 7 and a band layer 8. The lower piece 15 is formed by positioning the one end portion 18A inward in the tire axial direction and continuously winding it spirally and outward in the tire axial direction. The left and right lower pieces 15 and 15 are mutually
Is preferably reversed so that the uniformity of the tire is uniform, and the distance G between the inner edges of the lower pieces 15 is preferably
2 is 0.6 to less than the maximum belt ply width WB in this example.
It is 0.7 times.

Further, the belt piece 12 is placed on the outer surface of the lower piece 15 obtained by the first step as described above, and the belt piece 12 is wound, so that
Outer belt plies 7i and 7o are sequentially formed.

At this time, the outer end of the inner belt ply 7i is terminated so as not to exceed the outer edge 15a of the lower piece 15. Therefore, the other end portion 18B, which is the remaining portion of the band cord body 18 on which the lower piece 15 is formed, is exposed outward in the tire axial direction from the outer end of the inner belt ply 7i.
By continuously winding 8B continuously and spirally inward in the tire axial direction, the upper piece 16 connected to the lower piece 15 can be formed. At this time, it is preferable that the winding directions of the organic fiber cords 17 in the upper piece 16 be different from each other in the upper and lower directions in order to prevent the cords from being disturbed from entering between the cords 17 of the lower piece 15. It is desirable that the width be substantially constant over the entire width of the band layer 8 or gradually increase outward in the tire axial direction.

As shown in FIG. 8A, the band layer 8 may be formed only at the outer end of the outermost belt ply 7o. In such a case, as shown in FIGS. The belt ply 7i formed by winding the belt piece 12 on the drum 20 is formed in advance, and then the lower piece 15, the outer belt ply 7o, and the upper piece 16 are sequentially formed on the outer surface thereof. At this time, the outer edge of the lower piece 15 is connected to the inner belt ply 7i.
The lower piece 15 is substantially aligned with the outer end, and the inner belt ply 7 is
It is preferable to provide a lifting suppressing effect on i.

As shown in FIG. 8B, a band layer 8 may be provided at each outer end of the inner and outer belt plies 7i and 7o. In such a case, the band is repeated by repeating steps 1 to 3. The layer 8 can be easily formed.

[0029]

As described above, since the band layer forming method of the present invention is constituted, a U-shaped band layer 8 having an upper piece and a lower piece and formed by a spiral winding of an organic fiber cord is conveniently provided. It can greatly improve the high-speed durability of the tire and increase its productivity.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a tire obtained according to an embodiment of the present invention.

FIG. 2 is a plan view schematically showing a belt piece.

FIG. 3 is a perspective view schematically showing a wound state of a band cord.

FIG. 4 is a perspective view showing an example of a band cord body.

FIG. 5 is a perspective view showing an example of a band cord body.

FIG. 6 is a perspective view showing another example of the band cord body.

FIG. 7a is a diagram showing a first step;

FIG. 7b is a diagram showing a second step.

FIG. 7c is a diagram showing a third step;

FIG. 8 is a cross-sectional view showing another embodiment of the a-b band layer.

9A shows a first example for forming the band layer shown in FIG. 7A;
It is a diagram showing the step of.

FIG. 9b shows a second step for forming the band layer shown in FIG. 7a;
It is a diagram showing the step of.

FIG. 9c shows a third layer for forming the band layer shown in FIG. 7a;
It is a diagram showing the step of.

FIG. 10a is a schematic sectional view of a band layer for explaining a conventional technique.

FIG. 10B is a perspective view showing a state of forming a band layer for explaining the prior art.

[Explanation of symbols]

 2 Carcass 5 Tread portion 7i, 7o Belt ply 7 Belt layer 8 Band layer 12 Belt piece 15 Lower piece 16 Upper piece 17 Organic fiber cord 18 Band cord body 20 Drum 21 Tread reinforcing layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-36504 (JP, A) JP-A-63-315306 (JP, A) JP-A-56-82608 (JP, A) 52503 (JP, U) JP 47-2882 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29D 30/00-30/72 B60C 9/18-9/22 B60C 9/26

Claims (1)

(57) [Claims] 1. A belt layer comprising at least two belt plies disposed radially outward of a radially arranged carcass and inward of a tread portion, and an outer edge of the belt plies along a tire radial inner surface and an outer edge of the belt plies. a lower piece more than the outer end, contiguous with the outer edge of the bottom piece, of the band of the radial tire Ru comprising a band layer having an upper piece along the outer surface of said belt ply
In a molding method, one end of a band-shaped band cord body in which one to several organic fiber cords are aligned in parallel with each other is positioned on the outer peripheral surface of a drum for forming a tread reinforcing layer inward in the tire axial direction. first step by continuously winding in the tire axial direction outer side in a spiral shape to form the lower piece, on the outer surface of the lower piece obtained by a first step, the outer edge of the lower piece belt Wind a sheet-like belt piece so that it protrudes outward in the tire axial direction beyond the outer end of the ply
A second step of forming the belt ply by Rukoto, and the upper piece formed by winding the other end toward the axially inward of and in continuous to spiral the band cord member And a third step of forming a U-shaped band layer enclosing the outer end of the belt ply with the upper and lower pieces .