JP2996341B2 - Pneumatic radial tire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic radial tire having a belt layer and a reinforcing layer disposed radially outside a toroidal carcass layer.

[0002]

2. Description of the Related Art Conventionally, pneumatic radial tires which are easy to vulcanize and have good tire durability during high-speed running include, for example, a toroidal carcass layer in which a number of radially extending cords are embedded. A belt layer disposed radially outside of the carcass layer, and a reinforcing layer disposed radially outside of the carcass layer and overlapping the belt layer, wherein the reinforcing layer is in-phase bent in a wavy or zigzag shape. A wide band formed by covering a large number of reinforcing elements with a covering member made of a polymer material having a low elastic modulus is wound once (two times in the case of two layers) in the circumferential direction, and each band is wound. 2. Description of the Related Art There is known a body in which a longitudinal end and a longitudinal end of a body are overlapped and joined.

[0003] However, in such a pneumatic radial tire, the joining portion of the reinforcing layer is located at one location (2
In the case of a layer, it is unevenly distributed in two places), and since this joint is thick by lap joining, the uniformity of the tire is deteriorated and vibration may occur during running.
For this reason, as described in, for example, Japanese Patent Publication No. 35-3253, a large number of single-wire reinforcing elements that are bent in a wavy shape and covered with a covering member are spirally juxtaposed radially outside the breaker layer. The thing which comprised the reinforcement layer by winding around was proposed.

[0004]

However, in such a tire, a single-wire reinforcing element having low bending stiffness must be wound in close contact with the already wound reinforcing element in phase. However, there is a problem that the winding operation is difficult and a long time is required.

An object of the present invention is to provide a pneumatic radial tire that can be formed easily and with high efficiency.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toroidal carcass layer in which a number of radially extending cords are buried, a belt layer disposed radially outside the carcass layer, and a carcass layer. A reinforcing layer disposed radially outward and overlapping the belt layer, the reinforcing layer having a low elasticity and a plurality of reinforcing elements having the same phase bent in a wavy or zigzag shape. A belt-like body with a constant width covered with a covering member made of a high-molecular-weight material and having both ends in the width direction extending along the reinforcing element is spirally wound a plurality of times in the circumferential direction while abutting the ends in the width direction. Can be achieved.

[0007] The reinforcing layer of the present invention covers a plurality of reinforcing elements having the same phase as described above with a covering member, and forms a band-like body having a constant width extending along the reinforcing elements at both ends in the width direction. It is configured by spirally winding a plurality of times in the circumferential direction while abutting the side ends. Here, the wound band is a material having high bending rigidity in which a plurality of reinforcing elements are covered with a covering member, and the number of reinforcing elements embedded in the band in a single winding is equal to the number of the reinforcing elements. Since the winding operation can be performed at the same time, the winding operation is facilitated, and the time required for the winding operation is reduced, so that the efficiency is improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1, 2 and 3, reference numeral 1 denotes a pneumatic radial tire. The tire 1 has a carcass layer 2 having a toroidal shape. The carcass layer 2 has a large number of cords 3 extending in the radial direction embedded therein. At least one carcass ply 4 (in this embodiment, one carcass ply) is provided. A belt layer 6 is arranged radially outside the carcass layer 2, and a tread 8 having a plurality of main grooves 7 and the like is arranged radially outside the belt layer 6. The belt layer 6 has at least one
Belt plies, in this embodiment two belt plies
Each belt ply 11 has a tire equatorial plane
A large number of reinforcing cords made of non-extensible, for example steel, inclined in the opposite direction at an angle of 10 to 40 degrees with respect to 12, are embedded.

A reinforcing layer 15 slightly narrower than the belt layer 6 is disposed radially outside the carcass layer 2.
Reference numeral 15 is interposed between the carcass layer 2 and the belt layer 6 so as to overlap the belt layer 6 over substantially the entire width. The reinforcing layer 15 comprises at least one reinforcing ply, in this embodiment two reinforcing ply 16.
Each reinforcing ply 16 is formed by spirally winding an elongate strip 17 a plurality of times in the circumferential direction while abutting the width-side ends thereof. In this embodiment, the strip 17 is formed by winding one end in the width direction of the belt layer 6. The inner layer side reinforcing ply 16 is formed by continuously winding the belt layer 6 from the end to the widthwise other end, and then continuously wound from the widthwise other end of the belt layer 6 to the widthwise one end. Thus, the reinforcing ply 16 on the outer layer side is formed.
When the reinforcing layer 15 is formed from the spirally wound strips 17 as described above, the adjacent strips 17 are joined at their side ends, so that the joints are uniformly distributed in the circumferential direction. As a result, the uniformity of the tire 1 is improved, and vibration during running can be prevented.

The strip 17 is composed of a plurality of reinforcing elements 18 which are equidistant from each other and have the same phase, and a covering member 19 which covers these reinforcing elements 18. Here, each reinforcing element 18 is made of a cord (twisted wire) or a single filament, and is made of a non-extensible material such as steel or aramid fiber. These reinforcing elements 18 are covered members
In a plane parallel to the front and back surfaces of 19, it is bent in a wavy or zigzag shape, for example, a square wave, a triangular wave, or a sine wave, and all are arranged in the same phase. In this embodiment, the wavelength “a” of the reinforcing element 18 is set to an integral fraction of the outer peripheral length of the carcass layer 2. As a result, when the reinforcing element 18 of the strip 17 at a certain winding position and the reinforcing element 18 of the strip 17 adjacent to the strip 17 have the same circumferential position, as shown in FIG. It has the same phase. The covering member
Reference numeral 19 denotes a polymer material having a lower elastic modulus than the reinforcing element 18, for example, rubber or epoxy resin. Both ends (width direction both ends) of the covering member 19 are located outside the outermost reinforcing elements 18a and 18b (both ends of the reinforcing elements).
A pair of ears 20 is formed by projecting by approximately 1/2 of the distance d between the two. As a result, the covering member 19 has a constant width s, the width of which is substantially equal to the distance f between the outermost reinforcing elements 18a, 18b and the distance d between the reinforcing elements 18. It extends while bending along the element 18 in a wavy or zigzag manner. Then, the band-shaped body 17 is spirally wound a plurality of times in the circumferential direction while abutting the widthwise side ends, that is, the outer ends of the ear portions 20, and the adjacent band-shaped bodies 17 are butt-joined. The band 17 wound in this manner is composed of a plurality of reinforcing elements.
18 is covered with a covering member 19 and has a higher bending rigidity than a single-wire reinforcing element, and the number of reinforcing elements 18 buried in the strip 17 in one winding Since winding can be performed at the same time, the winding operation is facilitated, and the time for winding is shortened, so that the efficiency is improved.

In the above embodiment, the reinforcing layer
15 is superimposed on almost the entire width of the belt layer 6,
In the present invention, the belt layer 6 may be disposed so as to overlap only at both ends in the width direction. Further, in the above-described embodiment, the width of the reinforcing layer 15 is slightly smaller than the width of the belt layer 6, but in the present invention, the width is the same as the belt layer 6, or is slightly wider than the belt layer 6. Reinforcement layer 15
May project outward from the belt layer 6 at both ends in the width direction. Here, even when the reinforcing layer is disposed only at both ends in the width direction of the belt layer 6 as described above, the outer end in the width direction of the reinforcing layer may be projected outward from the belt layer 6. Further, in the above-described embodiment, the reinforcing layer 15 is disposed between the carcass layer 2 and the belt layer 6, but in the present invention, the reinforcing layer may be disposed between the belt layer 6 and the tread 8. Alternatively, it may be arranged between the belt plies 11 constituting the belt layer 6.

[0012]

Next, test examples will be described. In this test, a strip having the same width as the total width of the reinforcing layer (165 mm) was wound twice in the circumferential direction, and the longitudinal end and the longitudinal end of each strip were overlapped and joined. The comparative tire having the constituted reinforcing layer and the bent strip having a width of 20 mm are shown in FIGS.
As shown in Fig. 4, a reinforcing ply was formed by helically winding 8 times while butt-joining to form a reinforcing ply, and a test tire having a reinforcing layer formed by laminating two such reinforcing plies was prepared. Here, the structure of each tire described above is the same as that of the tire described in FIG. 1 except for the reinforcing layer, and the size of each tire is 11 / 70R22.5. Also, the reinforcing element of each tire is
3 + 9 + 15 × 0.15 steel cord is formed by bending along a sine wave with amplitude h of 5 mm and wavelength a of 53.7 mm.
In addition, such a reinforcing element is provided in the belt-shaped body of the test tire.
Eight pieces are buried at regular intervals, while 64 pieces are buried in the reinforcing ply of the comparative tire at regular intervals. Next, each tire is filled with an internal pressure of 7.5 kg / cm ² and run on a test drum at a speed of 3 km / h while applying a load of 2400 kg, and the longitudinal force fluctuation (RF
V) was measured. The result was 145 kg for the comparative tire but reduced to 68 kg for the test tire.

[0013]

As described above, according to the present invention, a pneumatic radial tire having a reinforcing layer can be formed easily and with high efficiency.

[Brief description of the drawings]

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

FIG. 2 is a development view near a reinforcing layer.

FIG. 3 is a sectional view taken along the line II of FIG. 2;

[Explanation of symbols]

 1 ... pneumatic radial tire 2 ... carcass layer 3 ... cord 6 ... belt layer 15 ... reinforcing layer 17 ... strip 18 ... reinforcing element 19 ... covering member

Claims (1)

(57) [Claims] 1. A toroidal carcass layer in which a large number of cords extending in the radial direction are embedded, a belt layer disposed radially outside the carcass layer, and a belt layer disposed radially outside the carcass layer. Overlapping reinforcing layers,
Wherein the reinforcing layer is formed by covering a plurality of reinforcing elements having the same phase, which are bent in a wave shape or a zigzag shape, with a coating member made of a polymer material having a low elastic modulus. A pneumatic radial tire, wherein a belt-like body having a constant width whose end extends along a reinforcing element is spirally wound a plurality of times in a circumferential direction while abutting width-side ends.