JP2000198311A - Tire reinforcement and pneumatic tires - Google Patents

Abstract

(57) [Summary] [Problem] As a reinforcing material used for a reinforcing layer of a tire, a wavy or spiral crimping process having a plurality of crimping ratios is performed, and the tire after bending is sufficiently bent. Provided are a tire reinforcing material and a pneumatic tire that can maintain the points and sufficiently exhibit the effects of crimping. SOLUTION: A tire reinforcing material 1 made of a linear material such as a filament or a cord is subjected to a crimping process so that a plurality of portions having different crimp ratios are continuous in the longitudinal direction, and the reinforcement is performed. A pneumatic tire is constructed by using the material 1 for at least one of the reinforcing layers. The crimp rate of this reinforcing material is set to 0.05% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tire reinforcing material and a pneumatic tire used for a reinforcing layer of a tire.

[0002]

2. Description of the Related Art In pneumatic tires such as radial tires, reinforcing layers such as filaments or cords made of high-carbon steel or synthetic resin are provided in parallel in a reinforcing layer such as a belt. It is used as a sheet covered with a rubber material.

[0003] As a reinforcing element in the tire reinforcing layer, a linear material in a straight form is generally used, but there is a problem that elongation and flexibility are not good, and shock absorption and fatigue resistance are poor. For this reason, for example, the practical use of a reinforcing material having a single-filament structure made of high carbon steel and subjected to a crimping process (so-called corrugation process) in a wavy or spiral shape has been considered. .

[0004] However, a reinforcing material such as a crimped steel filament increases flexibility but has a problem in elongation characteristics under a low load. For example, when a tensile test is performed on a crimped filament, the wavy shape and the spiral shape due to the crimping process first expand in a straight shape due to the tensile load. An inflection point (primary elasticity limit) appears at the cut point. This inflection point exists in a relatively low load range as shown in FIG. 11B in the load-elongation characteristic diagram. Therefore, when a load equal to or greater than the inflection point is applied, the wave shape or the spiral shape due to the crimping process does not restore to the original state, and permanent deformation is generated, which is the same as when a straight filament is used. become.

When the inflection point due to the primary elastic limit is close to the lift rate at the time of tire vulcanization, the physical properties after vulcanization are the same as when a straight reinforcing material is used,
In terms of tire performance, the characteristics of using the crimped reinforcing material cannot be exhibited.

In order to solve the above-mentioned problem, two types of shaping processes, that is, a small spiral process having a substantially spiral shape and a relatively large undulation process different from the custom-formed process, are performed. Although a filament has been proposed (Japanese Utility Model Laid-Open No. 7-24995), in this case, a large undulation exists at the time of the filament wire, but the undulation is caused by a tension at the time of embedding in rubber and a force acting upon a process handling after embedding. As a result, at the time of the product tire, the filament is not changed from the conventional filament having no undulation and subjected to a single spiral processing.

[0007] The present invention has been made in view of the above, and as a reinforcing material such as a filament or a cord used for a reinforcing layer of a tire, a special crimping process in which portions having different crimp rates are combined is performed. Thereby, the inflection point of the load-elongation characteristics can be retained even in the tire after vulcanization, and the tire reinforcing material that can sufficiently secure the effect of using the crimped reinforcing material for the reinforcing layer, An object of the present invention is to provide a pneumatic tire having a moderate elongation at the time of a product and excellent driving stability, fatigue resistance and durability by using a reinforcing material.

[0008]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the invention of claim 1 is a tire reinforcing material comprising a linear material such as a filament or a cord. The crimping process is performed such that a plurality of portions having different crimp rates are continuous over the entire portion.

The plurality of portions having different crimp rates have different crimp rates due to a change in one or both of amplitude and pitch.

According to a third aspect of the present invention, the tire reinforcing material is a reinforcing material formed by crimping with a two-dimensional waveform, and a plurality of portions having different crimp rates are alternately continuous without overlapping. The invention according to claim 4 is characterized in that the tire reinforcing material is a reinforcing material formed by spiral crimping, and a plurality of portions having different crimp rates are alternately formed without overlapping. It is continuous.

It is particularly preferable that the reinforcing material has a crimping ratio of 0.05% or more as a whole as determined by the following formula.

Crimping rate (%) = 100 (BA) / A where A: weight per unit length when straight (g / g)
m) B: Weight per unit length after crimping (g / m) That is, if the crimping ratio of the entire reinforcing material is less than 0.05%, the effect of performing crimping is reduced. Because. The upper limit of the crimp rate varies depending on the location and purpose of the reinforcing layer constituting the tire, and it is possible to provide a crimp rate of 10% or more or more as needed.

In the above, it is preferable that a plurality of portions having different crimp rates have a crimp rate of 0.05% or more.

Further, the reinforcing material is preferably made of a linear material such as a filament or a cord having a tensile modulus of 1500 kgf / mm ² or more.

That is, the tensile modulus of the reinforcing element is 1
If it is less than 500 kgf / mm ² , the reinforcing effect as a reinforcing element will be small, and the effect of crimping will hardly be obtained.

According to an eighth aspect of the present invention, there is provided a pneumatic tire using the tire reinforcing material according to any one of the first to seventh aspects as a reinforcing element for at least one reinforcing layer. It is particularly preferable that the reinforcing layer is at least one of the belt layers from the viewpoint of improving the performance of the tire.

[0017]

In the tire reinforcing material of the present invention, since a plurality of portions having different crimp rates are continuously crimped in the longitudinal direction, a plurality of inflection points in load-elongation characteristics are obtained. Will have. Therefore, in a pneumatic tire in which this reinforcing material is used for at least one of the reinforcing layers such as a belt layer, even if one of the inflection points of the reinforcing material is near the lift rate at the time of tire vulcanization, the warping is not performed. An inflection point can be maintained in the tire after sulfurization, and in a low load range, flexibility can be maintained due to the effect of crimping, and the elongation of the reinforcing material itself can be suppressed.

[0018]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged view of a tire reinforcing material having a single filament structure which has been subjected to two-dimensional or three-dimensional crimping. FIG. 2 shows a cross section of a sheet (10) covered with a rubber material (2).

The reinforcing material (1) is made of a steel straight filament (1a) made of high carbon steel and is subjected to, for example, a corrugated crimping process by the method shown in FIG. In particular, the reinforcing material (1) in the present invention comprises a plurality of portions having different crimp rates over the entire length in the longitudinal direction of the filament (1a), for example, a large wave portion (3a) and a small wave portion (3
b) is obtained by performing a crimping process of a composite shape that is alternately continued for each required length without overlapping.

The above-mentioned portions having different crimping ratios may change one or both of the amplitude (W1) (W2) and the pitch (P1) (P2) regularly or irregularly. The single-filament reinforcing material (1)
Has a plurality of inflection points as shown by (a) in the load-elongation characteristic diagram of FIG. 11 due to a combination of a plurality of crimp rates. (C) in FIG. 11 shows the characteristics of the straight filament.

The plurality of portions having different crimp ratios, for example, the large wave portion (3a) and the small wave portion (3b) in the figure are not limited to those which change and are continuous at every pitch as shown in FIG. , A plurality of pitches or the like may be used for each length, and may be continuous, or may be continuous via a straight portion.

The reinforcing material (1) having a single filament structure is usually 0.1 mm in the case of a tire for a passenger car.
Those having a wire diameter of 1 to 1.0 mm are used, and those having a wire diameter of 0.1 to 2.5 mm are used for trucks, bus tires and the like. Of course, a filament having a wire diameter other than the above can be used.

A method of crimping having a plurality of portions having different crimp rates will be described with reference to FIG.

FIG. 3 shows an example in which two types of crimp rates of a large wave portion (3a) and a small wave portion (3b) are alternately and continuously crimped. 1a) shows a straight filament before processing, and (4) and (5) show a pair of tooth-shaped rolls which are appropriately driven by driving means.

By guiding the straight filament (1a) through the pair of toothed rolls (4) and (5),
By meshing the tooth profiles (4a) (4b) and (5a) (5b) having a difference in height on the outer circumference of the tooth profile rolls (4) (5),
As shown in FIG.
Alternatively, a wave-shaped crimping process in which large wave portions (3a) and small wave portions (3b) having different pitches are alternately continued is performed.

The amplitude of this waveform depends on the tooth profile (4a)
(4b) and (5a) (5b) can be determined by the depth of engagement, and the pitch of the waveform can be determined by the spacing between the tooth profiles (4a) (4b) and (5a) (5b).

Further, as the shape of the wavy crimping of the reinforcing material (1), a sine wave as shown in FIG. 1 or FIG. 4A, a triangular wave as shown in FIG. Various wave shapes such as a trapezoidal wave as in C) can be used. These can be set by the cross-sectional shapes of the tooth profiles (4a) (4b) and (5a) (5b) of the apparatus of FIG. These may be either longitudinal waves or transverse waves in use as a reinforcing layer.

Further, the reinforcing material (1) may be subjected to a spiral crimping process described later. In addition, a combination of a corrugated and spiral crimping process may be used.

FIG. 5 shows a reinforcing member (1) made of a single filament made of steel similar to the above, and a plurality of portions (13a) having different crimp rates over the entire length in the longitudinal direction.
(13b) shows a case in which spiral crimping is performed alternately for each required length without overlapping.

Also in this case, in the portions (13a) and (13b) having different crimp rates, one or both of the amplitude (spiral diameter) and the pitch are changed regularly or irregularly. Thus, the crimp rates are different, and the combination of the plurality of crimp rates has a plurality of inflection points in the load-elongation characteristics.

The spiral crimping is performed using, for example, a spiral processing machine shown in FIG.
Guide holes (8) in the hydraulic servo shakers (6) and (7)
a) A guide plate (8) (9) having (9a) is connected, and a straight filament (1a) is passed through guide holes (8a) (9a) of the guide plates (8) (9). Exciter (6)
By driving (7) in a 90 ° phase with a waveform as shown in FIG. 7 (b), the spiral crimping process shown in FIG. 5 can be performed. In this case, the amplitudes and pitches of the different crimp ratio portions (13a) and (13b) are determined by the vibrator (6).
It can be arbitrarily determined by the amplitude and phase difference according to (7).

In the above embodiment, the case where the tire reinforcing material (1) is made of a single filament made of steel has been described as an example. A so-called twisted cord obtained by twisting filaments made of synthetic fibers, or a cord made of a braid braided with the above-mentioned filaments, or another linear material having a high tension can be used. It can be carried out by applying a wave-like or spiral-like crimping process so that a plurality of portions having different crimp rates are continuous.

In any of the above-described wavy and spiral crimping processes, the crimping rate of the entire reinforcing material determined by the following equation is set to 0.05% or more to maintain the effect of the crimping process. Shall be. Among them, those having a crimp rate of 0.05% or more in each of the plurality of crimp rate portions are particularly preferable.

Crimp rate (%) = 100 (BA) / A where A: weight per unit length when straight (g /
m) B: Weight per unit length after crimping (g / m) That is, a steel filament having a wire diameter of 0.25 mm is used as a material, and a plurality of portions having different crimp ratios are alternately formed at every pitch. A continuous wavy crimp in the form shown in FIG. 1 was performed. This reinforcing material (1) is covered with a rubber material in parallel with the number of ends of 60 pieces / 25 mm, and is vulcanized to a width of 25 m.
A belt-shaped sample having a thickness of 3 mm and a thickness of 3 mm was manufactured and tested for fatigue life. The results shown in Table 1 below were obtained.

In the test, the sample was subjected to JIS
L1017 "Test method for chemical fiber tire cord" Reference 1 Fatigue strength defined in 2 of (1) According to the method based on the Firestone method (Method A), a force of 40 kgf is repeatedly applied to break the sample. The number of cycles until was counted. At the same time, a conventional 1 × 4 × 0.25 twisted cord obtained by twisting four straight filaments is used for comparison with a case where a straight filament is used for comparison, with 15 ends / 25 mm. The same test was carried out for each of the vulcanizates embedded in a rubber material.

[0037]

[Table 1]

As a result, in the case of a filament having a crimp rate of less than 0.05% obtained by the above equation, the fatigue life is extremely deteriorated as in the case of the straight filament, but the crimp is reduced. When the rate is 0.05% or more, the fatigue life is increased as compared with the conventional twisted cord.

Therefore, the crimp ratio as a reinforcing material is
The content of 0.05% or more is particularly effective in improving fatigue resistance.

As the reinforcing material, a linear material having a tensile modulus of 1500 kgf / mm ² or more is preferably used.

That is, as shown in Table 2 below, as a material having a different tensile modulus, a twisted cord made of steel, aramid fiber, and vinylon fiber is crimped, and this cord is used as a reinforcing element. As shown in FIG. 9, a belt covered with a rubber material is formed.
A tire having a size of 195 / 60R15 was manufactured using the layer belt, and its cornering power (CP) and vertical axis acceleration were measured. The results were as shown in Table 1 below.

The vertical axis acceleration was measured by measuring the acceleration in the vertical axis direction generated when the tire was run on a drum with projections at a speed of 60 km / H and crossed over the projections. 10 when single crimping is applied to each material cord
It was indicated by an index as 0.

[0043]

[Table 2]

As described above, the effect of improving the CP and reducing the vertical axis acceleration is that the modulus is 1500 kgf /
Since the effect becomes greater when the thickness is ² mm ² or more, the reinforcing material for tires (1) has a weight of 1500 kgf / mm.
Preferably, it has a tensile modulus of ² or more.

The tire reinforcing material (1) described above is formed by arranging a large number of the reinforcing materials (1) in layers and covering them with a rubber material (2) so as to be embedded therein.
0) and buried in a rubber material as a reinforcing layer for a belt layer or a side wall of a pneumatic tire and as a reinforcing layer for a bead portion.

At this time, as for the state of juxtaposition of the reinforcing members (1), as shown in FIG. The phase may be changed every one to several or a required number of groups as shown in C), or may be randomly arranged in parallel and covered with a rubber material to form a sheet as shown in FIG. Can also.

Further, in addition to the same crimping ratio as each reinforcing material in the reinforcing layer, each reinforcing material may be individually or one to one.
The crimping ratio can be different for each required number. Most of the reinforcing material constituting one reinforcing layer of the tire is made of the above-mentioned linear materials having different crimp rates, and the remaining reinforcing material is subjected to a conventional single crimping process. Alternatively, these may be alternately arranged and arranged in parallel, and covered with a rubber material to form a sheet.

In particular, it is particularly preferable to design and implement the crimping ratio of the reinforcing material (1) so as to be favorable for bringing out the tire performance.

As described above, the reinforcing material (1) made of a crimped linear material is used for at least one reinforcing layer such as a belt layer in a tire as shown in FIG. 9 or FIG. Thus, a pneumatic tire (T) such as a radial tire is formed. In FIGS. 9 and 10, (21)
Indicates a belt layer, (22) indicates a belt reinforcing layer, (23) indicates a double-sided bent belt reinforcing layer, (11) indicates a carcass, (12) indicates a tread, and (14) indicates a bead portion.

The pneumatic tire (T) thus configured
By using the above-mentioned reinforcing material (1) for at least one layer of the reinforcing layer, fatigue resistance can be improved, an inflection point can be ensured even after vulcanization, and elongation at low load is reduced. It can contribute to improving performance such as flexibility, steering stability and durability.

[0051]

EXAMPLE 1 A steel filament having a wire diameter of 0.25 mm was used as a raw material, and a plurality of portions having different crimping ratios were alternately continued between the toothed rolls (4) and (5) in FIG. (A) in the case of a crimped reinforcing material, and (b) in the case of a conventional crimped reinforcing material on the filament,
In the case of a 1 × 4 × 0.25 twisted cord using the same filament (c) and in the case of a straight type reinforcing material of the same filament (d), a large number of each are covered in parallel with a rubber material to form a sheet. did. The obtained sheet having a thickness of 1.1 mm is used for both of the two belt layers (21) and (21) of the tire in FIG.
Fifteen tires were manufactured. Obtained tire (A) ~
With respect to (D), the cornering power (CP), the vertical acceleration, and the running distance of the belt folding were measured and compared. The results are shown in Table 3 below. In addition, when each single crimped filament was used as a reinforcing material, (b) was set to 100 and indicated by an index.

[0052]

[Table 3]

As a result, the cornering power, the vertical axis acceleration, and the belt running distance were all better than those obtained when a single crimped filament was used as a reinforcing material. In particular, cornering power and durability were good.

Example 2 Using a steel filament having a wire diameter of 0.175 mm as a raw material, two hydraulic servo adders were driven with the waveforms of FIGS. 7A and 7B through the apparatus of FIG. Spiral crimping, reinforcing material with a single crimp rate,
A plurality of reinforcing materials having different crimp ratios were manufactured, and the reinforcing materials were coated in parallel with a rubber material to obtain a sheet having a thickness of 1.0 mm.

Each of the sheets (a) and (b) thus obtained was connected to two cross belts (1500d / 2) made of aramito fiber cord in the tire structure of FIG. 10 (A).
Main strand, number of ends 23 / 25mm, crossing angle 23 °) (2
On top of 1), a two-layer belt reinforcement layer (2 ° at 0 ° to the circumferential direction)
2) to produce a tire of size 195 / 60R15. At the same time, in the tire structure shown in FIG. 10B, the sheet (b) is disposed on the aramid fiber belt layer (21) as a double-sided bent belt reinforcing layer (23) to have a size of 195/200. A 60R15 tire was obtained.

The high-speed durability of each of these tires was examined. The results are shown in Table 4 below. The high-speed durability was indicated by an index with 100 when a crimped filament having a single crimp rate was used as a reinforcing material.

[0057]

[Table 4]

As a result, it has been found that the high-speed durability can be improved by using the reinforcing material of the present invention in which a plurality of portions having different crimp rates are continuous for the reinforcing layer.

[0059]

As described above, according to the tire reinforcing material of the present invention, since a plurality of portions having different crimp rates are continuously crimped without overlapping, the load-
The tire after vulcanization has an inflection point due to crimping even if one inflection point is near the lift rate at the time of tire vulcanization, because it has multiple inflection points in elongation characteristics In the low load range, the elasticity of the reinforcing material itself can be suppressed due to the effect of the crimping process and the extension of the reinforcing material itself can be suppressed.

Accordingly, the pneumatic tire using the above-mentioned reinforcing material can sufficiently exhibit the effect of using the reinforcing material subjected to the corrugated or spirally crimped processing for the reinforcing layer, and has a complicated and arbitrary elongation. Characteristics can be secured, steering stability,
Good high-speed durability and fatigue resistance can be ensured.

In particular, when the crimping ratio as the reinforcing material is set to 0.05% or more, the above-mentioned effect becomes remarkable, and the reinforcing material becomes a tensile material. By using a linear material having a modulus of 1500 kgf / mm ² or more, the function is more effectively exhibited.

[Brief description of the drawings]

FIG. 1 is a partially enlarged front view showing one embodiment of a tire reinforcing material of the present invention.

FIG. 2 is a cross-sectional view of a part in which the reinforcing members are juxtaposed and covered with a rubber material to form a sheet.

FIG. 3 is a partial schematic explanatory view showing one example of a method for producing a tire reinforcing material of the above.

FIG. 4 is a schematic front view of a part illustrating a wave shape obtained by crimping each of (A), (B) and (C).

FIG. 5 is a partially enlarged front view illustrating a tire reinforcing material crimped into a spiral shape.

FIG. 6 is a partial schematic explanatory view showing one example of a method for manufacturing a tire reinforcing material according to the embodiment.

FIGS. 7A and 7B are front views showing a driving waveform and a spiral shape of the spiral processing machine, respectively.

8 (A), 8 (B), 8 (C), and 8 (D) are explanatory views showing the arrangement of tire reinforcing members.

FIG. 9 is a schematic cross-sectional view showing an embodiment of a pneumatic tire using a tire reinforcing material for a belt as a tire reinforcing layer.

FIGS. 10A and 10B are schematic cross-sectional views showing an example of use as a reinforcing layer in another tire.

FIG. 11 is a load-elongation characteristic diagram of a tire reinforcing material.

[Explanation of symbols]

 (1) Reinforcing material (1a) Straight filament (2) Rubber material (3a) Large wave part (3b) Small wave part (4) (5) Toothed roll (4a) (4b) (5a) (5b) Toothed part (6) (7) Hydraulic servo shaker (8) (9) Guide plate (13a) (13b) Different crimp ratio (21) Belt layer (22) Belt reinforcement layer (23) Bent belt reinforcement layer

Claims (9)

[Claims] 1. A tire reinforcing material comprising a linear material such as a filament or a cord, which has been subjected to a crimping process so that a plurality of portions having different crimp rates are continuous in the longitudinal direction. A tire reinforcing material characterized by the following. 2. The tire reinforcing material according to claim 1, wherein the plurality of portions having different crimp ratios have different crimp ratios due to a change in one or both of amplitude and pitch. 3. The reinforcing material for a tire obtained by crimping with a two-dimensional waveform, wherein a plurality of portions having different crimp rates are alternately continued without overlapping. Tire reinforcement. 4. The reinforcing material for a tire according to claim 1, wherein the reinforcing material is formed by spiral crimping, and a plurality of portions having different crimp rates are alternately continued without overlapping. . 5. The tire reinforcing material according to claim 1, wherein a crimp ratio of the entire reinforcing material determined by the following formula is 0.05% or more. Crimp rate (%) = 100 (BA) / A where A: weight per unit length when straight (g / g)
m) B: Weight per unit length after crimping (g / m) 6. The reinforcing material for a tire according to claim 5, wherein each of the plurality of portions having different crimp rates has a crimp rate of 0.05% or more. 7. A tensile modulus of 1500 kgf / mm.
The tire reinforcing material according to any one of claims 1 to 6, comprising ^two or more linear materials. 8. A pneumatic tire using the tire reinforcing material according to any one of claims 1 to 7 as a reinforcing element for at least one reinforcing layer. 9. A reinforcing layer using the reinforcing material for a tire according to any one of claims 1 to 7, wherein the reinforcing layer comprises at least one of the belt layers.
The pneumatic tire according to claim 8, which is a layer.