JPH08132822A - Pneumatic tire - Google Patents

Abstract

PURPOSE: To improve durability by forming the reinforcing layer of a drown section with a main section buried with cords in one or multiple rubber cover bodies and strips made of cover rubber extended to the sides from the main section and wound spirally in the peripheral direction and having edge sections overlapped in sequence. CONSTITUTION: When a composite belt layer is to be formed with slant cords 51 -53 and a reinforcing layer 14, strips prepared in advance are spirally wound in the peripheral direction from the prescribed position at one end in the axial direction on the slant cords 51 , 52 stretched on a belt/tread molding drum. Edge sections of the strips are overlapped with each other, or a main body and the edge sections are overlapped in sequence. When the winding of the first layer is completed, the strips are cut off, and the second layer is likewise formed in the opposite direction from this position. When the stretching of the reinforcing layer 14 is completed, the third slant cords 53 and a tread 4 are stretched on it, then they are integrated with the carcass portion molded in the separate process by the ordinary method, and the whole is vulcanization-molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire having a reinforcing layer including reinforcing elements extending in the circumferential direction around a crown portion of a carcass and improving durability of the tire.

[0002]

2. Description of the Related Art Regarding the reinforcement of the crown portion of the carcass corresponding to the base of the tread portion of a pneumatic tire,
A plurality of layers in which non-stretchable cords represented by steel cords are inclined at a shallow angle (15 to 35 °) with respect to the equatorial plane of the tire are stacked so that the cords intersect each other. Combined belt layers are known. On the other hand, in heavy duty radial tires for which high internal pressure is applied such as those for trucks, buses, and off-the-road, especially for reinforcement of the crown portion of a flat tire, the belt layer having the above structure lacks rigidity, and therefore a straight or corrugated belt is used. A belt layer comprising a plurality of reinforcing cords formed by circumferential spiral winding of rubberized strips, for example one or, in many cases, side-by-side extending cords. It has been conventionally proposed to use a reinforcing belt layer instead of the belt layer or to add this reinforcing layer to the belt layer of the inclined code. The layers of the spiral winding of the strip will be described in more detail with the aid of the drawings.

FIG. 9 is a partial cross-sectional view of the reinforcing layer during tire production, and FIG. 10 is a partial cross-sectional view of the same layer after vulcanization and curing. In FIG. 9, reference numeral 10 is a strip in which a plurality of cords 11 are arranged side by side and coated with a coating rubber 12.
This strip is, for example, though not shown,
Strip from one end to the other end on the circumference of the scrap crown
The side edges of 10 are abutted on each other and wound in a circumferential spiral to form a layer 13. The vulcanized layer 13 is formed with a hardened reinforcing layer 14 that is continuous in the axial direction. FIG. 11 is a partial cross-sectional view of another example of the reinforcing layer during tire production, and FIG. 12 is a partial cross-sectional view of the same layer after vulcanization and curing. Similarly, in the example shown in FIG. 11, in forming the layer 13 by the strip 10, the strip 10 is partially overlapped and spirally wound,
After vulcanization and curing, the reinforcing layer 14 shown in FIG. 12 is obtained.

[0004]

[Problems to be Solved by the Invention] However, the strip 10
Is obtained by arranging the cords and crimping the coated rubber.
In the longitudinal direction of the strip, there are usually a small amount of rubber protrusions 15 and defects 16 (Fig. 9), so that after vulcanization, these parts each have an air-filled space m and a cord contact n.
(Fig. 10) tends to occur. On the other hand, when the layer is formed by the overlap of the strip (FIG. 11), the thick portion 17 and the thin portion 18 are formed adjacent to each other in the axial direction, and the cord contact after vulcanization curing corresponds to each of these portions. n and void m (Fig. 1
2) will occur.

When the void m is formed in the reinforcing layer 14, the adhesion between the reinforcing layer 14 and other reinforcing elements or other members overlapping with the void m becomes poor, while the code contact n is the code due to the friction between the codes. It causes the tire to run out and shortens the running life of the tire. The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a tire having a reinforced layer having excellent durability in a crown portion.

[0006]

According to the present invention, a toroidal carcass is used as a body reinforcement and is composed of one or a plurality of filaments arranged in a substantially circumferential direction around a crown portion of the carcass. In a tire reinforced by arranging at least one layer having a cord as a reinforcing element, the reinforced layer is a rubber coating containing one or a plurality of cords, and the cord is embedded in the rubber coating. A pneumatic tire is characterized in that it is formed by circumferentially spirally winding a strip having a main portion and an edge portion from which the coating rubber extends laterally, the edge portions being successively overlapped.

In a preferred embodiment of the reinforcing layer, a strip having an edge portion on one side of which the coated rubber extends extends in a circumferential spiral winding in which the edge portion and the main portion are sequentially overlapped, and further on both sides of the main portion. An example is a structure formed by a circumferential spiral winding in which the edge portion and the main portion of the strip having the edge portion where the coating rubber extends and the edge portions are sequentially overlapped.

[0008]

In the present invention, the reinforcing layer is formed by spirally winding a strip having a cord-containing main portion and a coating rubber edge portion on the side thereof. In this case, the edge portion and the main portion are formed. Since they are axially connected to each other by overlapping portions or edges, cord contact does not occur in the reinforcing layer, and even if the overlapping portion becomes thicker than other portions when winding the strip. Since the portion having an excessive thickness softens and flows during vulcanization molding and is well fitted to other adjacent members, a void at the strip joining position or an air trap can be advantageously prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below with reference to the drawings. 1 is a sectional view of a tire showing an embodiment of the present invention, FIG. 2 (a) is a partial plan view of a strip, FIG. 2 (b) is the same sectional view, and FIG. 3 is a joining state when the strip is wound. FIG. 5 is a sectional view showing an example, and FIG. 5 is a partial sectional view of the reinforcing layer after vulcanization and curing. In FIG. 1, a tire 1 has a toroidal carcass 2
Is used as a body reinforcement, and at least one reinforcing layer 14 having a plurality of cords arranged substantially in the circumferential direction around the crown portion 3 of the carcass 2 as a reinforcing element is arranged and strengthened. The reinforcing layer 14 is then coded as shown in FIG.
A rubber-coated body containing one or a plurality of 11
Main part M in which the cord is embedded and the rubber cover 12
Is formed by circumferential spiral windings (FIGS. 3 and 5) of a strip 10 having edges V 1 extending in which the edges V 1 are successively overlapped.

FIG. 1 shows an example of a flat heavy load tire.
The dregs 2 is composed of one ply in which steel cords are arranged in a direction orthogonal to the equatorial plane O. In the crown portion 3 of the tire, a belt layer 5 having a width substantially equal to the tread is disposed between the tread 4 engaging with the road surface and the carcass 2 for reinforcement.

[0011] Belt layer 10 is steel - Turkey - layer 5 ₁ inclined arranged de, 5 _2, 5 ₃ and made of reinforcing layer 14, mosquito - widest first layer close to Kas 2 5 ₁ and the first layer and overlapping broad second layer 5 ₂ co according to this layer - de is inclined at approximately 18 ° relative to the equatorial plane O, intersect each other. These two layers are the main layers. On top of that, the third layer 5 ₃ (around 80% of layer 5 ₁ ) is a little narrower.
U-width) - de second layer 10 ₂ co - it is inclined at substantially the same angle in the same direction as the de. The cord twist structure of these graded layers is 3 + 9 + 15 × 0.23.

[0012] Two reinforcing layer 14 in this embodiment inclined co - second de, between the third layer 5 _2, 5 _3, which was arranged in substantially the same width as the third layer _3, the reinforcing layer The strip 10 which constitutes 14 (Fig. 2) has a 4 × 4 × 0.23 structure as the code 11
Eleven rust cords are arranged, and thin rubber sheets are crimped from the top and bottom. A pair of left and right edges V is provided on both sides of the main part M, and the widths w and v of the main part and the edges are respectively. 30 mm
And 5 mm. On the other hand, the gauges h of the main part and the edge part,
i is 2.1 mm and 1.6 mm. As a preferred structure of the strip 10, a non-stretchable organic fiber cord represented by aramid other than a metal material such as steel can be used as the cord, and the number of cords is 5 to 15, The width v of the edge is 3 to 10 mm.

The graded code layers 5 _{1 to} 5 ₃ and the reinforcing layer 14 shown in FIG.
Strip from the predetermined position of the axial end at node layer 5 _1, 5 on _2, previously prepared - when molding composite belt layer, the belt tread forming drum on the bonded slope U and
10 is spirally wound in the circumferential direction. In this case, the edges V of the strips 10 are overlapped with each other as shown in FIG. 3 or the strips 10 are shown as a partial sectional view in FIG.
The main part M and the edge part V of the are sequentially stacked. After the winding of the first layer is completed, the strip is cut and the second layer is formed again in the same direction in the reverse direction from the position, or after the winding of the first layer is completed, the strip is continuously cut without cutting the strip. The second layer can be formed by winding the layers up to the winding start end in the same manner. After the reinforcing layer is attached in this way, the third inclined code layer 5 ₃ and the tread 4 are attached on top of that, and after that, they are combined with the portion of the carcass formed in another step by a conventional method, and vulcanized. Mold. When the edges of the vulcanized reinforcing layer 14 are overlapped with each other, as shown in FIG. 5, the main portion corresponding position M ′ including the code of the strip is the edge corresponding position V ′ not including the code. And will alternate in the axial direction.
When the main portion and the edge portion of the strip are overlapped with each other, although not shown, the cords are arranged over the entire width of the reinforcing layer substantially at intervals included in the main portion.

In addition to the arrangement example shown in FIG. 1, the reinforcing layer 4 can be arranged with a required width between the carcass 2 and the belt layer. Further, depending on the application of the tire, it may be provided between the belt layer of the inclined code and the tread, or the entire belt layer may be formed of a reinforcing layer.

When the reinforcing layer 14 is formed by the strip 10, the winding start end is placed in the central portion of the crown portion 3 in addition to the above-described example, and from this position, the spiral continuous winding is performed in an S shape or a Z shape. It is also possible to form a plurality of reinforcing layers up to the central portion of the crown portion 3 by turning.

FIG. 6A is a partial plan view showing a second embodiment of the strip, and FIG. 6B is a sectional view of the strip. The feature of this embodiment is that a code extending in a corrugated manner is applied as a reinforcing element. In this case, the edge V of the coated rubber is periodically formed with a portion with a narrow width v corresponding to the crest of the wave and a portion with a wide width corresponding to the valley, but upon winding, the overlap of the strip is the width from the side edge. It is preferable to carry out in the range of V 2.

FIG. 7A is a partial plan view showing a third embodiment of the strip, and FIG. 7B is a sectional view of the strip. The feature of this embodiment is that the strip 10 is provided with the edge portion V 1 only on one side of the main portion M 1. When forming a reinforcing layer using this type of strip, as shown in a sectional view in FIG. The strip is a cord serving as a reinforcing element, and it may be applied by embedding a relatively short cord in the longitudinal direction intermittently in the coated rubber except a cord that continuously extends unless the purpose is impaired. it can.

[0018]

[Effect] To confirm the effect of the tire according to the present invention, 11
The structure shown in FIG. 1 is applied to a tire of /70R22.5 size, and the reinforcing layer is formed by the spiral winding in which the edges are overlapped with each other as shown in FIG. 3 as the tire 1 according to the present invention.
The tires of Comparative Examples 1 and 2 shown in FIG.
A 10,000-knot endurance test was conducted. In this case, 11 strips of corrugated steel cord (wavelength 32 mm, single amplitude 1.2 mm) of 3 + 9 × 0.19 structure were used as strips for forming the reinforcing layer and were covered with rubber, except for the presence of edges. Used in common. The strip used in the tire of the present invention has a width v
Is provided on both sides of the main portion M with the edge portion V of 8.8 mm, Comparative Example 1,
The strip used for 2 had the edges omitted.

The test tire is assembled on the rim of 22.5 × 8.25,
It was filled with an internal pressure of 8.0 Kgf / Cm ² and applied with a load of 3300 Kgf, and was run on a steel drum (diameter 2 m) having a smooth surface at a constant speed of 65 Km / H. Room temperature was 38 ° C.
As a result of dissecting and examining the tire after running, no abnormality was found in the tire according to the present invention, whereas in the tire of Comparative Example 1, 13 places of air and 54 places of adhesion on the circumference of the reinforcing layer. Defective, the tire of Comparative Example 2 had air in 27 places and 1
Adhesion failure was observed at 6 places.

Next, the structure shown in FIG. 1 is applied to a tire of 11R22.5 size, and a reinforcing layer is provided as a tire 2 and 3 according to the present invention by spirally winding by overlapping edges shown in FIGS. 4 and 8, respectively. The formed tires were mixed with the tires of Comparative Examples 3 and 4 shown in FIGS. In this case, as a strip for forming the reinforcing layer, a strip of aramid code of 3000 d / 2 arranged in 10 straight lines and covered with rubber was used in common except for the presence or absence of the edge portion. The strip used in the tire 2 according to the invention has edges V with a width v of 10 mm on both sides of the main part M, and the tire 3 according to the invention has edges V with the same width on one side of the main part M. The edges of the strips used in the tires of Comparative Examples 3 and 4 were omitted.

These test tires were mounted on a 22.5 × 8.25 rim, filled with an internal pressure of 7.0 Kgf / Cm ² , loaded with a load of 3300 Kgf, and run under the same conditions as the above test. As a result of dissecting and examining the tires after running, no abnormality was found in any of the tires 2 and 3 according to the present invention, whereas in the tire of Comparative Example 3, there were 9 air-filled areas on the circumference of the reinforcing layer.
Inadequate adhesion was observed at 23 locations, and the tire of Comparative Example 4 was found to have air in 23 locations and poor adhesion at 5 locations.

As described above, the edge portion is formed by the strip having the main portion in which the cord is embedded in the reinforcing layer arranged on the outer periphery of the crown portion of the carcass and the edge portion where the coating rubber extends laterally from the main portion. The tire of the present invention, which is formed by circumferentially winding spirally overlapping, has remarkably excellent durability.

[Brief description of drawings]

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

FIG. 2A is a partial plan view showing a first embodiment of the strip.

FIG. 2 (b) is a sectional view of the strip.

FIG. 3 is a cross-sectional view showing a joined state when the strip is wound.

FIG. 4 is a cross-sectional view showing a joined state when the strip is wound.

FIG. 5 is a partial cross-sectional view of a reinforcing layer after vulcanization and curing.

FIG. 6 (a) is a partial plan view showing a second embodiment of the strip.

FIG. 6 (b) is a sectional view of the strip.

FIG. 7 (a) is a partial plan view showing a third embodiment of the strip.

FIG. 7 (b) is a cross-sectional view of the strip.

FIG. 8 is a cross-sectional view showing a joined state when the strip is wound.

FIG. 9 is a cross-sectional view showing a joined state when the strip of the comparative example is wound.

FIG. 10 is a partial cross-sectional view of the reinforcing layer after vulcanization and curing.

FIG. 11 is a cross-sectional view showing a joined state when the strip of the comparative example is wound.

FIG. 12 is a partial cross-sectional view of the reinforcing layer after vulcanization and curing.

[Explanation of symbols]

 1 Tire 2 Carcass 3 Crown 10 Strip 11 Code 14 Reinforcement layer M Strip main part V Strip edge

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[Procedure amendment]

[Submission date] March 2, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

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

FIG. 2A is a partial plan view showing a first embodiment of a strip. (B) is sectional drawing of a strip.

FIG. 3 is a cross-sectional view showing a joined state when the strip is wound.

FIG. 4 is a cross-sectional view showing a joined state when the strip is wound.

FIG. 5 is a partial cross-sectional view of a reinforcing layer after vulcanization and curing.

FIG. 6A is a partial plan view showing a second embodiment of the strip. (B) is sectional drawing of a strip.

FIG. 7A is a partial plan view showing a third embodiment of the strip. (B) is sectional drawing of a strip.

FIG. 8 is a cross-sectional view showing a joined state when the strip is wound.

FIG. 9 is a cross-sectional view showing a joined state when the strip of the comparative example is wound.

FIG. 10 is a partial cross-sectional view of the reinforcing layer after vulcanization and curing.

FIG. 11 is a cross-sectional view showing a joined state when the strip of the comparative example is wound.

FIG. 12 is a partial cross-sectional view of the reinforcing layer after vulcanization and curing.

[Explanation of symbols] 1 Tire 2 Carcass 3 Crown 10 Strip 11 Code 14 Reinforcement layer Main part of M strip V Edge of strip

Claims (4)

[Claims] 1. A toroidal carcass is used as a body reinforcement, and a cord composed of one or a plurality of filaments arranged substantially circumferentially around a crown portion of the carcass is used as a reinforcing element. In a tire having at least one of the layers to be reinforced arranged, the reinforced layer has one cord,
Alternatively, in a rubber-coated body including a plurality of strips, a strip having a main portion in which a cord is embedded and an edge portion to which the coated rubber extends laterally from the main portion, has a circumferential spiral winding in which the above-mentioned edge portions are sequentially overlapped. A pneumatic tire characterized by being formed by turning. 2. The reinforcing layer is formed by circumferentially spirally winding a strip having an edge portion on one side of the main portion where the coating rubber extends so that the edge portion and the main portion sequentially overlap with each other. The pneumatic tire according to claim 1. 3. The reinforcing layer is formed by circumferentially spirally winding a strip having edges extending from the main rubber on both sides of the main portion, wherein the edges and the main portion are sequentially overlapped. The pneumatic tire according to claim 1. 4. The reinforcing layer is formed by circumferentially spirally winding a strip having edges extending from the main rubber on both sides of a main portion, the edges being successively overlapped with each other. 1 pneumatic tire.