JPH09142112A - Reinforcing structure for bead part of tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire which is light in weight, which can easily be manufactured, and which has sufficient rigidity. SOLUTION: An annular reinforcing member 4 is arranged along the circumferential direction of a tire 1 in a bead part 3 of the tire 1. The section of the reinforcing member 4 is of a slender shape, and the member 4 is arranged, ranging from the bead part 3 to the vicinity of a side wall part. The reinforcing member 4 is constituted of a first layer 5, a second layer 6, which is fixed to the periphery of the first layer 5, and an apex 7, which is made of hard rubber, which has a triangular section and is fixed to the periphery of the second layer 6. The first layer 5 is formed by winding a belt-like body 10, which is obtained by covering a plurality of linear substances 8, which are made of a Kevlar fiber and arranged side by side, with rubber 9, more than one time and in a laminated manner. The second layer 6 is formed by winding a belt-like body 13, which is obtained by covering a plurality of linear substances 11 made of nylon and placed side by side with rubber 12, more than one time and in a laminated manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing structure for a bead portion of a tire.

[0002]

2. Description of the Related Art Generally, in a tire, an annular bead wire made of steel wire is arranged in a bead portion, and a bead portion structure in which an apex made of hard rubber having a triangular cross section is attached to the outer periphery of the bead wire is used. is there.
The bead wire and the hard apex increase the rigidity around the bead portion (the portion from the bead portion to the sidewall portion) of the tire to ensure good steering stability of the vehicle. However, this alone does not provide sufficient rigidity as a tire for use in vehicles that have become larger and faster in recent years.

For this reason, as shown in FIGS. 4 and 5, for example, a twisted wire 32 made of a plurality of steel wires is continuously formed on the side portion of the apex 30 at a predetermined angle with respect to the circumferential direction of the bead wire 31. Conventionally, a structure has been proposed in which many tires are attached to the tire to reinforce the periphery of the bead portion of the tire.

[0004]

However, in the structure shown in FIGS. 4 and 5, the bead wire 31 is formed of steel wire and the side portion of the apex 30 is formed, although sufficient rigidity is obtained. Since the twisted wire 32 made of steel wire is arranged in the above, there is a problem that the weight increases and it becomes difficult to reduce the weight of the tire.
Moreover, a large number of twisted wires 32 are provided on the side of the apex 30.
There was also a problem that the work of securely attaching the tape so as not to peel it off was very troublesome.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is a reinforcing structure for a bead portion of a tire which is lightweight, easy to manufacture, and capable of ensuring sufficient rigidity. To provide.

[0006]

In order to achieve the above object, in the invention described in claim 1, an annular reinforcing member is arranged in a bead portion of a tire, and the reinforcing member is made of a non-metallic wire. A first layer obtained by laminating and winding an object, and a second layer formed by laminating and winding a non-metallic linear object which is provided on the outer periphery of the first layer and has a rigidity lower than that of the linear object constituting the first layer. And an apex made of hard rubber having a triangular cross section provided on the outer periphery of the second layer, and at least the first layer of the first layer and the second layer has a substantially rectangular cross section. Thus, the width in the radial direction is formed larger than the width in the axial direction.

According to a second aspect of the present invention, in the first aspect, at least one of the first layer and the second layer is formed by laminating a plurality of linear objects arranged in parallel and covered with rubber. It is wound and formed in an annular shape.

According to a third aspect of the present invention, in the first aspect, at least one of the first layer and the second layer is formed by winding one rubber-coated linear object in parallel and in a laminated manner to form an annular shape. It is formed in.

According to the invention described in claim 4, claims 1 to 3
In any one of the above, the linear material forming the first layer is made of Kevlar. In the invention according to claim 5,
In any one of Claims 1-4, the linear object which comprises the said 2nd layer consists of nylon.

Therefore, according to the first aspect of the present invention, the first layer and the second layer are formed by laminating and winding non-metallic linear objects, respectively, so that they are lightweight and easy to manufacture.
In addition, at least the first layer of the first layer and the second layer is formed so that the width in the radial direction is larger than the width in the axial direction so as to have a substantially rectangular cross section. In other words, the first layer and the second layer are arranged in the portion from the bead portion to the sidewall portion of the tire. And these 1st layer and 2nd layer have rigidity higher than the apex made from rubber by the laminated winding of the nonmetallic linear material. Therefore, unlike the structure in which a rubber apex having a triangular cross-section is simply provided on the outer circumference of the annular bead wire, high rigidity required for the portion from the bead portion to the sidewall portion of the tire can be guaranteed. Moreover, the second layer has a lower rigidity than the first layer, and the rubber apex has a lower rigidity than the second layer. For this reason, the rigidity can be gradually changed from the bead portion of the tire that requires particularly high rigidity to the sidewall portion that requires flexibility.

According to the second aspect of the invention, at least one of the first layer and the second layer can be easily lowered by laminating and winding a strip-shaped body in which a plurality of linear objects arranged in parallel are covered with rubber. Can be manufactured at a cost.

According to the invention of claim 3, the first layer or the second layer excellent in strength can be obtained by parallel winding and laminated winding of one rubber-coated linear object. According to the invention of claim 4, by forming the first layer with Kevlar, it is possible to make it lightweight and excellent in strength.

According to the fifth aspect of the present invention, by forming the second layer of nylon, the second layer can be made lighter and more rigid than the apex rubber.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a view showing a cross section of a pneumatic tire 1, particularly a turnup portion 2a of a carcass layer 2,
That is, it is a view mainly showing the bead portion 3. In the figure,
The right side is the outside of the tire 1 and the left side is the inside. The carcass layer 2 is folded back from the inside of the tire 1 toward the outside. An annular reinforcing member 4 is arranged in the bead portion 3 of the tire 1 along the circumferential direction of the tire 1. The reinforcing member 4 has an elongated cross section,
It is arranged from the bead portion 3 to the vicinity of the upper side wall portion in FIG.

As shown in FIGS. 1 and 2, the reinforcing member 4 includes a first layer 5, a second layer 6 fixed to the outer periphery of the first layer 5 and an outer periphery of the second layer 6. The apex 7 is made of hard rubber and has a triangular cross-section. The first layer 5 is formed by laminating a strip-shaped body 10 obtained by coating a plurality of non-metallic linear objects (made of, for example, Kevlar) 8 arranged in parallel with a rubber 9 in a laminated manner. In addition, in the drawing, the first layer 5 is formed by laminating a strip-shaped body 10 in which five linear objects 8 are arranged in parallel 16 times. As a result, the width of the first layer 5 in the radial direction is larger than that in the axial direction so that the first layer 5 has a substantially rectangular cross section.

The second layer 6 is the same as the first layer 5,
A band-shaped body 13 formed by coating a plurality of non-metallic linear objects (made of nylon, for example) 11 arranged in parallel with rubber 12
Are laminated and wound. In addition, in the drawing, the second layer 6 is formed by laminating the strip-shaped body 13 in which seven linear objects 11 are arranged in parallel 25 times. As a result, the width of the second layer 6 in the radial direction is larger than that in the axial direction so that the second layer 6 has a substantially rectangular cross section. The width of the second layer 6 in the axial direction is narrower than that of the first layer 5.

The linear material 11 made of nylon or the like in the second layer 6 has a lower rigidity than the linear material 8 made of Kevlar or the like in the first layer 5. Moreover, the linear object 11 in the second layer 6 is thinner than the linear object 8 in the first layer 5. Further, the rubber 12 in the second layer 6 is
It may be the same as the rubber 9 in layer 5, or first
It may be harder than the rubber 9 in the layer 5.

The apex 7 may be formed, for example, by extruding a cord-shaped body having a triangular cross section with a rubber extruder and adhering the cord-shaped body to the outer periphery of the second layer 6. It may be formed by fitting an endless ring shaped by injection molding on the outer periphery of the second layer 6. The method of attaching the string-shaped body can easily form the apex 7, and the method of fitting the ring-shaped body can obtain a superior strength because the apex 7 cannot be cut. The rubber forming the apex 7 may be the same as the rubber 12 in the second layer 6, or may be harder than the rubber 12 in the second layer 6.

In this embodiment, since the reinforcing member 4 is constructed as described above, the following operational effects can be obtained. (1) The reinforcing member 4 is made of a first layer 5, a second layer 6 fixed to the outer periphery of the first layer 5, and a hard rubber having a triangular cross section fixed to the outer periphery of the second layer 6. It is composed of apex 7. And the 1st layer 5 and the 2nd layer 6 are comprised by the lamination winding of the nonmetallic linear objects 8 and 11, respectively. Therefore, it is lightweight and easy to manufacture.

(2) The first layer 5 and the second layer 6 are formed such that their widths in the radial direction are larger than their widths in the axial direction so that they each have a substantially rectangular cross section. Therefore, the first layer 5 and the second layer 6 are arranged over the portion from the bead portion 3 to the sidewall portion of the tire 1. Moreover, the first layer 5 and the second layer 6 are made of a non-metal linear material 8 such as Kevlar or nylon.
It is composed of 11 laminated windings. Kevlar is lightweight and very strong. Nylon is lightweight and more rigid than apex rubber. Therefore,
Unlike the conventional structure in which a rubber apex having a triangular cross section is simply provided on the outer circumference of an annular bead wire, high rigidity required for the portion from the bead portion 3 to the sidewall portion of the tire 1 can be guaranteed.

(3) The second layer 6 has lower rigidity than the first layer 5, and the rubber apex 7 has lower rigidity than the second layer 6. Moreover, the apex 7 has a triangular cross section, and is thinner toward the outer peripheral side. Therefore, the rigidity can be gradually changed from the bead portion 3 of the tire 1 that requires particularly high rigidity to the sidewall portion that requires flexibility.

(4) The rubber 12 of the second layer 6 having the linear material 11 made of nylon is harder than the rubber 12 of the first layer 5 having the linear material 8 of Kevlar which has higher rigidity than nylon. If the rubber of the apex 7 is harder than the rubber 12 of the second layer 6 provided with the linear objects 11, the first layer 5
There is no significant difference in rigidity between the second layer 6 and the second layer 6, and between the second layer 6 and the apex 7. Therefore, the rigidity of the tire 1 can be changed more gradually from the bead portion 3 to the sidewall portion.

(5) A plurality of linear objects 8 arranged in parallel,
Bands 10 and 13 in which 11 is covered with rubbers 9 and 12
Are laminated and wound a plurality of times to form the first layer 5 and the second layer.
Layer 6 can be produced more easily and at lower cost.

(6) Since the reinforcing member 4 becomes narrower from the inner circumference to the outer circumference, the arrangement state in the tire bead portion 3 can be made good. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 3, in the second embodiment, the structure of the first layer 5 and the second layer 6 in the reinforcing member 4 is different from that of the first embodiment. That is, in this embodiment, the first layer 5 is formed in a substantially rectangular cross section by winding the wire material 15 obtained by coating the single linear object 8 with the rubber 14 in parallel and in layers. ing. As a winding method, for example, the wire 15 may be wound a plurality of times (5 times in the drawing).
A plurality of parallel winding layers of the wire rod 15 are formed by parallel winding to form the innermost layer, and subsequently winding the wire rod 15 around the outer periphery of the parallel winding layer in the same manner. (16 layers in the drawing) are formed. Then, by winding the wire rods 15 in parallel and in layers in this manner, the first layer 5 having excellent strength can be obtained.
In addition, the wire rod 15 of each parallel winding layer in the circumferential direction of the first layer 5
When the winding is performed so that the slopes of the adjacent parallel winding layers are opposite to each other, the first layer 5 more preferable in terms of strength can be obtained.

The second layer 6 also includes the above-mentioned first layer 5
Similarly to the above, the wire 17 formed by coating the single wire 11 with the rubber 16 is wound in parallel and laminated to form a substantially rectangular cross section. This winding method is also the same as in the case of the first layer 5.

The present invention may be modified and embodied as follows, for example. (1) In each of the above-described examples, the number of parallel windings or the number of laminated windings may be appropriately changed when forming the first layer 5 and the second layer 6.

[0029]

According to the present invention, as described in detail above, the following excellent effects can be obtained. According to the invention of claim 1, it is lightweight and easy to manufacture, and the high rigidity required for the portion from the bead portion to the sidewall portion of the tire can be guaranteed. In addition, the rigidity can be gradually changed from the bead portion of the tire that requires particularly high rigidity to the sidewall portion that requires flexibility.

According to the second aspect of the present invention, at least one of the first layer and the second layer can be easily lowered by laminating and winding a band-shaped body in which a plurality of linear objects arranged in parallel are covered with rubber. Can be manufactured at a cost.

According to the third aspect of the invention, the first layer or the second layer having excellent strength can be obtained by parallel winding and laminating winding of one rubber-coated linear object. According to the invention of claim 4, by forming the first layer with Kevlar, it is possible to make it lightweight and excellent in strength.

According to the fifth aspect of the present invention, by forming the second layer of nylon, the second layer can be made lighter and more rigid than the apex rubber.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a first embodiment of a bead portion reinforcing structure of the present invention.

FIG. 2 is a partially cutaway perspective view showing an enlarged reinforcing member.

FIG. 3 is a partially cutaway perspective view showing a second embodiment of a reinforcing member.

FIG. 4 is a partially cutaway perspective view showing a conventional bead portion reinforcing structure.

FIG. 5 is a partially cutaway perspective view showing a twisted wire in an enlarged manner.

[Explanation of symbols]

1 ... Tire, 3 ... Bead part, 4 ... Reinforcing member, 5 ... 1st
Layer, 6 ... Second layer, 7 ... Apex, 8 ... Non-metallic linear object, 9 ... Rubber, 10 ... Band, 11 ... Non-metallic linear object,
12 ... Rubber, 13 ... Band, 14 ... Rubber, 15 ... Wire,
16 ... rubber, 17 ... wire rod.

Claims (5)

[Claims] 1. An annular reinforcing member is arranged in a bead portion of a tire, and the reinforcing member is provided on a first layer formed by laminating and winding a non-metallic linear object and an outer periphery of the first layer, Same first
From a second layer formed by laminating and winding a non-metallic linear object having a rigidity lower than that of the linear object constituting the layer, and an apex made of hard rubber having a triangular cross section provided on the outer periphery of the second layer. At least a first layer of the first layer and the second layer is configured,
A reinforcing structure for a bead portion of a tire, the width of which in the radial direction is formed to be larger than the width in the axial direction so as to have a substantially rectangular cross section. 2. The at least one of the first layer and the second layer is formed in an annular shape by laminating and winding a band-shaped body obtained by coating a plurality of linear objects arranged in parallel with rubber. The reinforcing structure of the bead portion of the tire described in. 3. The tire according to claim 1, wherein at least one of the first layer and the second layer is formed into an annular shape by winding one rubber-covered linear object in parallel and in laminated winding. Reinforced structure of the bead part. 4. The reinforcing structure for a bead portion of a tire according to claim 1, wherein the linear material forming the first layer is made of Kevlar. 5. The reinforcing structure for a bead portion of a tire according to claim 1, wherein the linear material forming the second layer is made of nylon.