JPH1120406A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the replacing work of a belt member, and prevent the lack of parts by winding a bias cut strip material a plurality of times so as to be arranged in the tire width direction of the circumference of a carcass layer to form a belt layer. SOLUTION: Belt layers 5, 6 are formed by bias cutting a trip material 7 so that a plurality of reinforcing cords are inclined to the longitudinal direction is wound on the outer circumference of a catalyst layer 2 at substantially 0 deg. to the tire direction, and closely arranging a plurality of strip materials 7 in the tire width direction. The reinforcing cords are mutually crossed between the phase of the strip materials 7, and the tire width directional position of the lower layer side strip material 7 is kept coincident with that of the upper layer side strip material 7. Thus, an optional belt width consisting of the multiple of the width of the strip material 7 can be set by changing the number of turns of the strip material 7 (the number of arrangements in the tire width direction).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire provided with a belt layer outside a carcass layer, and more particularly, to a setup change operation in a belt cutting process and a belt member changing operation in a tire forming process. While reducing
The present invention relates to a pneumatic tire capable of preventing a part from being cut in a tire forming process and greatly improving productivity.

[0002]

2. Description of the Related Art A pneumatic radial tire is characterized in that a belt layer having a width substantially equal to a tread width is arranged outside a carcass layer in a tread portion. In general, the belt layer is configured by arranging at least two layers in which reinforcing cords such as steel cords are inclined with respect to the tire circumferential direction at a bias so as to cross each other.

Conventionally, as a method for forming a belt layer of a pneumatic radial tire as described above, a belt-shaped sheet is obtained by applying a plurality of reinforcing cords that have been previously aligned in a calendering process and rubberizing unvulcanized rubber. After the rubberized sheet material is cut into a belt-equivalent width with a bias, the cut pieces are used as a belt member so as to have a required circumferential length in the tire circumferential direction according to the tire size.

However, when using a belt member which is bias-cut to a belt equivalent width as described above, it is necessary to prepare various types of belt members for each tire size having a different belt width. For this reason, in the belt cutting process, it was necessary to frequently change the setup for changing the cutting dimension every time the belt size changed. Moreover, in order to correspond to a plurality of types of tire sizes, it is necessary to prepare a necessary amount of belt members of the corresponding type in advance and manage the inventory.

[0005] The belt-shaped belt member is wound around a reel and mounted on a tire forming machine and supplied to a molding process. When the tire size is changed, a belt member corresponding to the tire size is used. It had to be replaced with the reel. Furthermore, in the tire forming process, if the stock is out of stock when the belt member corresponding to the tire size during the forming operation is insufficient, the forming operation has to be temporarily stopped until the belt member is manufactured. There was a problem.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce setup change work in a belt cutting step and replacement work of a belt member in a tire forming step, and to prevent part breakage in a tire forming step. Another object of the present invention is to provide a pneumatic tire that can significantly improve productivity.

[0007]

According to the present invention, there is provided a pneumatic tire in which a belt layer is disposed outside a carcass layer in a tread portion. A belt material is formed by winding a strip material, which is bias-cut so as to be inclined with respect to the outer periphery of the carcass layer, several times so as to be aligned in the tire width direction.

[0008] By forming a belt layer by winding the strip-shaped strip material thus bias-cut plural times around the outer periphery of the carcass layer so as to be arranged in the tire width direction,
Since an arbitrary belt width can be set by changing the number of windings of the strip material, a common strip material can be used for belt widths of various tire sizes.

Therefore, it is only necessary to prepare a common strip material for various types of belt sizes, so that the work of changing the setup in the belt cutting process and the work of replacing the belt member in the tire forming process can be reduced. It is possible to prevent the running out of parts in the tire molding process and to greatly improve the productivity. Note that even if the belt layer is formed by winding the strip material as described above, the tire performance such as steering stability is hardly reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings. 1 and 2 illustrate a pneumatic radial tire for an automobile according to an embodiment of the present invention. In the figure, a carcass layer 2 is mounted between a pair of left and right bead portions 1, 1, and both end portions in the tire width direction of the carcass layer 2 are wound around a bead core 3 from the inside of the tire to the outside.

Outside the carcass layer 2 in the tread portion 4, two belt layers 5, 6 are embedded. The belt layers 5 and 6 are formed by applying a strip material 7 in which a plurality of reinforcing cords are bias-cut so as to be inclined with respect to the longitudinal direction on the outer periphery of the carcass layer 2 substantially in the tire circumferential direction.
° and a plurality of strips 7 are closely arranged in the tire width direction. Further, the reinforcing cords of the strip members 7 intersect each other between the layers, and are arranged such that the positions of the lower layer strip members 7 and the upper layer strip members 7 in the tire width direction substantially coincide with each other. .

Since the strip-shaped strip material 7 thus bias-cut is wound a plurality of times around the outer periphery of the carcass layer so as to be arranged in the width direction of the tire, the belt layers 5 and 6 are formed. By changing the (number of arrangements in the tire width direction), for example, an arbitrary belt width that is a multiple of the width of the strip material 7 can be set. Therefore, even if it is necessary to set various types of belt widths of the belt layers 5 and 6, a common strip material 7 may be prepared, so that a setup change operation in a belt cutting process and a belt member bridging in a tire forming process are performed. Replacement work can be reduced. In addition, since only a single type of strip material 7 needs to be retained in advance in a large amount, it is possible to prevent parts from being cut off in the tire forming process and to greatly improve productivity.

In the pneumatic tire configured as described above, the belt layers 5 and 6 are made of the strip material 7 and the reinforcing cords are divided in the tire width direction. Deformation of the tread is less likely to deform to a portion near the tread. Therefore, according to the present invention, the rolling resistance of the tire can be reduced, and the durability against fatigue in the buckling direction can be improved. In addition, tire performance such as steering stability can be secured to be equal to or greater than that of a conventional tire.

FIGS. 3 and 4 illustrate a pneumatic radial tire for an automobile according to another embodiment of the present invention. This embodiment is different from the embodiment of FIGS. 1 and 2 in that the strip members 7 constituting the two belt layers 5 and 6 are arranged so as to be shifted from each other in the tire width direction. . In the figure, the lower strip material 7
The total width of the portion where the overlap ratio defined by the ratio [(W / W ₀ ) × 100] of the width W of the upper layer side strip material 7 to the width W ₀ of the upper layer is 20 to 80% is the belt width. Layer 5, 6
Is set so as to occupy an area equal to or more than 80% of the overlap width B.

According to the tire, the same operation and effect as those of the above-described embodiment can be obtained.
In forming at least two belt layers 5 and 6 by winding, the integrated value of the portion where the overlap rate of the upper layer strip material 7 with the lower layer strip material 7 becomes 20 to 80% is the belt layer 5. 80% for the overlap width B of, 6
By occupying the above, a belt layer having a portion continuous in a plane is formed even if each of the tire cross sections is made of a thin strip material 7 and the lateral rigidity is improved, so that the steering stability is sufficiently improved. Can be secured.
When the integrated width of the portion where the overlap ratio between the layers of the strip material 7 is 20 to 80% is less than 80% of the belt overlap width B,
Since the displacement between the layers of the strip material 7 becomes insufficient,
The effect of improving the steering stability cannot be obtained.

In the present invention, the width W ₀ of the strip 7 constituting the belt layers 5 and 6 is preferably set to 10 to 30 mm. The width W ₀ of the strip material 7 is 10 mm
If it is less than 30 mm, the steering stability decreases, and if it exceeds 30 mm, it becomes difficult to cope with various belt widths. Further, it is preferable that the angle α of the reinforcing cord of the strip material 7 with respect to the tire circumferential direction is set to 10 to 30 °. When the angle α of the reinforcing cord is out of the range of 10 to 30 °, the steering stability is reduced.

When a plurality of strips 7 are wound at substantially 0 ° with respect to the circumferential direction of the tire, the strips 7 may be wound one by one on the outer periphery of the carcass layer 2. Alternatively, a plurality of coils may be wound simultaneously. If the splice portions of the plurality of strip members 7 are arranged so as to be dispersed in the tire circumferential direction, it is possible to improve uniformity. It is not always necessary to prepare a plurality of strip materials 7;
The strip material 7 may be inclined at an angle of 5 ° or less with respect to the circumferential direction of the tire and continuously wound in a spiral shape. In this case, since the splice portion of the strip material 7 does not substantially exist, uniformity is improved.

As a reinforcing cord of the strip material 7, a steel cord is preferable, but an organic fiber cord can also be used. As an organic fiber cord, for example,
At least one fiber selected from the group consisting of aromatic polyamide fibers, polyarylate fibers, polyparaphenylene benzobisoxazole fibers, polyvinyl alcohol fibers, rayon fibers, polyethylene terephthalate fibers, polyethylene 2,6-naphthalate fibers, and nylon fibers; Twisted twisted cords can be used.

[0019]

EXAMPLES Conventional tires and tires 1 and 2 of the present invention were manufactured with a tire size of 195 / 60R14, a common tire structure and dimensions other than the belt layer, and only a different belt structure as described below.

Conventionally , a belt member having a belt equivalent width obtained by bias cutting a plurality of steel cords so as to be inclined with respect to the tire circumferential direction is wound around the outer periphery of the carcass layer to form two belt layers. The cord angle of the belt layer with respect to the tire circumferential direction was 24 °.

Tire 1 of the Present Invention As shown in FIGS. 1 and 2, a 10 mm wide strip material in which a plurality of steel cords were bias-cut so as to be inclined with respect to the longitudinal direction was applied to the outer periphery of the carcass layer in the tire width direction. A plurality of belt layers were formed by winding a plurality of times so as to be lined up with each other, and the position of the strip material in the tire width direction was matched between the layers. The cord angle of the belt layer with respect to the tire circumferential direction was 25 °.

Tire 2 of the present invention As shown in FIGS. 3 and 4, a strip-shaped strip material in which a plurality of steel cords are bias-cut so as to be inclined with respect to the longitudinal direction is applied to the outer periphery of the carcass layer in the tire width direction. The belt material was wound a plurality of times so as to be arranged in a row to form two belt layers, and the position of the strip material in the tire width direction was shifted between the layers. The cord angle of the belt layer with respect to the tire circumferential direction is 25.
°.

The test tires were evaluated for steering stability and molding productivity by the following test methods, and the results are shown in Table 1. Driving stability: Each test tire was mounted on a domestic car with a displacement of 1600 cc at an air pressure of 220 kPa, and a feeling test was performed by five test drivers. The evaluation results were indicated by an index with the conventional tire being 100. The larger the index value, the better the steering stability.

Molding productivity: For each test tire, when continuously producing five types of tires having different sizes,
The forming time including the setup change time in the belt cutting step and the belt member changing time in the tire forming step was measured. The evaluation results are shown as indices with the reciprocal of the measured value of the conventional tire being 100. The larger the index value, the higher the productivity.

[0025] As is clear from Table 1, the tires 1 and 2 of the present invention are:
In each case, while maintaining the same steering stability as the conventional tire, the molding productivity was superior to the conventional tire.

[0026]

As described above, according to the present invention, in a pneumatic tire in which a belt layer is disposed outside a carcass layer in a tread portion, a bias is applied so that a plurality of reinforcing cords are inclined with respect to a longitudinal direction. By forming the belt layer by winding the cut strip material a plurality of times around the outer periphery of the carcass layer in the tire width direction, a common strip material can be used for various types of belt widths. It is possible to reduce the setup change work in the belt cutting step and the replacement work of the belt member in the tire forming step, and also prevent the parts from being cut in the tire forming step, thereby greatly improving the productivity.

[Brief description of the drawings]

FIG. 1 is a plan view showing a belt structure of a pneumatic radial tire according to an embodiment of the present invention.

FIG. 2 is a meridional section of the tire according to the embodiment of FIG. 1;

FIG. 3 is a plan view showing a belt structure of a pneumatic radial tire according to another embodiment of the present invention.

FIG. 4 is a meridional section of the tire according to the embodiment of FIG. 3;

[Explanation of symbols]

 2 Carcass layer 4 Tread section 5, 6 Belt layer 7 Strip material

Claims (6)

[Claims] In a pneumatic tire in which a belt layer is arranged outside a carcass layer in a tread portion, a strip material in which a plurality of reinforcing cords are bias-cut so as to be inclined with respect to a longitudinal direction is formed on an outer periphery of the carcass layer. A pneumatic tire in which a belt layer is formed by winding a plurality of times so as to be arranged in the tire width direction. 2. An integrated width of a portion where the belt layer is laminated in at least two layers and an overlap ratio of an upper layer side strip material to a lower layer side strip material is 20 to 80% is an overlap width of the belt layer overlap width. The pneumatic tire according to claim 1, which accounts for 80% or more. 3. The pneumatic tire according to claim 1, wherein the reinforcing cord of the strip material is a steel cord. 4. The pneumatic tire according to claim 1, wherein the reinforcing cord of the strip material is an organic fiber cord. 5. The pneumatic tire according to claim 1, wherein the strip material is continuously spirally wound at an angle of 5 ° or less with respect to the tire circumferential direction. 6. The strip material has a width of 10 to 30 mm.
The pneumatic tire according to any one of claims 1 to 5, wherein an angle of the reinforcing cord with respect to a tire circumferential direction is 10 to 30 °.