JPH0323365B2 - - Google Patents

Description

Detailed Description of the Invention The present invention comprises a radial carcass, a breaker having two or more layers in which fiber or metal cords are arranged in the cord layer, and a protective band overlapping the side edges of the breaker. The present invention relates to a pneumatic tire for a vehicle.

Rolling resistance plays a significant role in this type of pneumatic vehicle tire. Amid energy shortages and rising prices, efforts are being made to reduce the rolling resistance of pneumatic tires in order to reduce gasoline consumption in vehicles.

An object of the present invention is to provide a pneumatic tire for a vehicle that maintains and enhances running safety and decisively weakens rolling resistance.

The present invention solves this problem as follows.
That is, the pneumatic tire for a vehicle of the present invention includes a breaker with a cut edge having a cut edge of the cord;
at least one protective strip overlaid on the side edge of the breaker, the cords of adjacent breaker layers intersect and are symmetrical with respect to the circumferential direction of the tire, with a distance of 21° to 21° to this direction; forming an angle of 30°, said protective band being made of a woven fabric with very low elongation fiber or metal cords extending in the form of a wave, the individual waves of this wave forming almost or completely with the circumferential direction of the tire. The fabric is configured such that, due to its corrugation, it still has an elongation of 0.3 to 3% in the finished tire.

The basis of this invention is the idea that the breaker characteristics automatically change depending on the speed due to a special breaker structure. The features according to the invention result in the following advantages. This means that the tire breaker is relatively flexible at low speeds up to about 120 km/h, i.e. radially, laterally and circumferentially; on the other hand, at high speeds above about 120 km/h. It hardens to prevent elongation and prevent, for example, the undulating deformation of the top of the tread that often occurs in tires with flexible breakers.

In the case of tires used exclusively at relatively low speeds, a cord angle of 21° to 30°, especially 24°, between the individual layers of the breaker already results in a considerable reduction in rolling resistance. It can be achieved. Such tires can even withstand speeds of more than 100 km/h without additional protection, and can also be used to provide the necessary safety at the lower speeds of passenger cars.

With the configuration of this invention, we succeeded in reducing the rolling resistance of the tire in the range of 0 to 120 km/h, which accounts for 95% of the total traveling distance, and at the same time, further ensuring high-speed characteristics. In order to reduce the rolling resistance in that case, on the one hand the use of a cut edge breaker with a cut edge of the cord and on the other hand a narrower breaker than in known tires or a somewhat blunter cord angle between 21° and 30° It is important to use a breaker with

In order to ensure that the high-speed characteristics as a whole are not adversely affected, at the same time as mentioned above, additionally overlapping protective bands are provided on the breaker. This protective band still has an elongation of 0.3 to 3% in the finished tire.

The advantage of using a narrow breaker is that the crown can be easily formed when the tire is completed.

An advantage resulting from a further narrow breaker is a reduction in serrations at the breaker edges.

Furthermore, the use of textile cords in the protective band has the advantage of particularly great savings in material and particularly great reductions in weight. This is because two or more steel layers are replaced by fiber layers in the side region of the breaker.

A more detailed explanation will be given based on figures showing two embodiments.

The pneumatic tire for a vehicle shown in Fig. 1 includes a radial carcass 1 having a fiber or metal cord provided in a cord layer, and a normal cord having a width of about 10 mm narrower than a conventional size extending into the cord layer. It consists of a cut edge breaker 2 with cut edges of two layers of cords held in place, and two protective bands 3 made of a so-called blind weave fabric made of fiber or metal cords with extremely low elongation and hardened with rubber. The cords 3'' of this protective band 3 extend in a waveform in a plane perpendicular to the axial direction of the tire, as shown in Figure 5, so that only the individual cords 3'' extend. Instead, the entire fabric of the protective band forms a wave shape on the tire and is approximately parallel to the circumferential direction of the tire, as shown in Figure 2, i.e., at almost or completely zero angle. Due to the corrugation, the fabric in the protective band 3 is configured such that it still has an elongation of 0.3 to 3% in the finished tire.

Furthermore, the cords in the two layers 4 and 5 of the cutting edge breaker 2 intersect with each other as shown in FIG. 2, and are symmetrical with respect to the circumferential direction of the tire. , instead of the usual angle of 16°~20°, 21°~
It forms a 30° angle. This is because it has been found that at speeds that are not very fast, the rolling resistance of tires is significantly reduced when the angle is greater than 20 degrees.

Furthermore, the protective strip 3 is arranged in particular on the radially outer side of the breaker 2 and extends axially beyond the side edge of the breaker 2, so that it overlaps the breaker (Fig. 2). ).

In the tire of FIG. 1, a reduction in rolling resistance is achieved by using the cutting edge breaker 2 of the configuration described above and by selecting a narrow breaker width. on the other hand,
A protective band with a woven fabric made of cords whose corrugation shape is precisely adjusted so that in the finished tire it still has an elongation of 0.3 to 3%, in order to have no overall adverse effect on the high-speed characteristics. 3 is used.

As a result, at speeds up to approximately 120 km/h, the protective band stretches in response to the centrifugal force caused by the current speed, thus continuing to provide the tire with a moderate amount of flexibility in all directions. and about 120 mph
When the speed exceeds a kilometer, the elongation curve of the protective band 3 based on the elongation of the waveform of the fabric reaches its limit, the fabric becomes taut, and the tire becomes reinforced.

This reinforcing action prevents deformation of the tire tread top and separation of the breaker edge, which conventionally occur at high speeds.

In the case of another second embodiment shown in FIG. 3, the tire has a radial carcass 1' and a cut edge consisting of two layers 4', 5' as in the first embodiment shown in FIG. It has a breaker 2' and a protective band 3' of another embodiment.

The protective band 3' in this second embodiment is the same as the protective band 3 in the first embodiment in that it has a woven fabric made of fibers or metal cords with extremely low elongation provided in the cord layer. However, the corrugation of the cord lies within the plane of the fabric of the protective band 3', as shown in FIG. 4, so that the entire fabric of the protective band lies almost entirely within the plane of the cylinder body on the finished tire. The individual corrugations make an angle of little or no zero degrees with the circumferential direction of the tire, and the corrugations are the same as in the first embodiment, i.e. the fabric in the finished tire still has an angle of 0.3 to 30 degrees depending on its corrugation. % elongation. The engineering effect of the guard strip 3' with a corrugated cord is the same as in the case of the guard strip 3 in the first embodiment.

Since the pneumatic tire for vehicles of the present invention has the above-described configuration, the protective band is not applied at relatively slow speeds of up to about 120 km/h.
The tire expands within the range of 0.3 to 3% due to the centrifugal force depending on the speed at that time, but it also maintains a moderate amount of flexibility in all directions.
The cords in each layer that also constitute the breaker function as cutting edge breakers having the specific arrangement described above, so that rolling resistance can be reduced.

On the other hand, at high speeds of approximately 120 km/h or higher, the elongation curve of the protective band enters the saturated region, and even if the centrifugal force due to high speed becomes strong, the fabric does not elongate any further, but rather becomes tense, causing the tire to tire. This prevents the deformation of the top of the tread and the separation of the breaker edge, allowing for good running at high speeds.

[Brief explanation of drawings]

Fig. 1 is a partial radial cross-sectional view of a pneumatic vehicle tire in which the waveform of the cord of the protective band is in a plane perpendicular to the axial direction, and Fig. 2 is a diagram of the tire in Fig. 1 developed in a plan view. , FIG. 3 is a partial radial cross-sectional view of a pneumatic vehicle tire in which the waveform of the cord of the protective band is in a plan view of the fabric of the protective band, and FIG. 4 is a view of the tire of FIG. 3 developed in a plan view. FIG. 5 is a longitudinal cross-sectional view of the cord of the protective band used in the tire of FIG. 1 and having corrugations extending in a plane perpendicular to the axial direction. 1, 1'... Radial carcass, 2, 2'... Cut edge breaker, 3, 3'... Protective band, 3''... Corrugated cord, 4, 4', 5, 5'... Breaker layer.

Claims (1)

[Claims] 1. A breaker having a radial carcass, two or more layers in which fiber or metal cords are arranged in the cord layer, and at least one protective band overlapping the side edge of the breaker. In a pneumatic tire for a vehicle, the tire has a breaker with a cut edge of the cord, and at least one protective strip superimposed on the side edge of the breaker, the cords of adjacent breaker layers intersect and symmetrically with respect to the circumferential direction of the tire, making an angle of 21° to 30° with this direction; , the individual waves of this corrugation make almost or completely zero angle with the circumferential direction of the tire, and the fabric, due to its corrugation, still has an angle of 0.3 in the finished tire.
A pneumatic tire for a vehicle characterized by having an elongation of ~3%. 2. The pneumatic tire for a vehicle according to claim 1, characterized in that the protective bands are two protective bands overlapped on both side edges of a breaker having an edge where the cord is cut. . 3. The pneumatic tire for a vehicle according to claim 1, characterized in that a protective band is disposed between the tread and the breaker. 4. The pneumatic tire for a vehicle according to claim 1, wherein the waveform of the cord of the protective band lies within a plane perpendicular to the axial direction. 5. The pneumatic tire for a vehicle according to claim 1, wherein the waveform of the cord of the protective band is within the plane of the fabric of the protective band.