JPS5844004Y2 - Pneumatic radial tires for passenger cars with a comfortable ride - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a radial tire for passenger cars that provides excellent ride comfort.

In general, radial tires use cords with high elastic modulus, such as steel cords, as reinforcement materials in the belt layer, and are far superior to regular bias tires in terms of wear resistance and cornering characteristics. However, the difficulty in use is that the riding comfort is extremely poor.

The reason for this is that multiple plies of tension-resistant cords arranged parallel to the tire's equatorial plane, twisted, or intersecting at a very shallow angle are buried in the crown of the tire as a belt, which reduces the thickness of the tread. Extremely high directional bending rigidity,
During rolling on the road, the tread is difficult to deform when passing over protrusions on the road, and the impact that occurs here is not absorbed by the sidewall11, and is transmitted from the tire bead to the rim wheel and axle, causing vibration. On the other hand, in addition to the circumferential distribution of small irregularities on the tire tread, some eccentricity cannot be avoided, so even on a flat road surface, vibrations occur in the form of periodic shocks every time the tire rotates. Again, this is because it is not completely absorbed by the sidewalls and is transmitted to the axle.

Originally, the basic characteristics of pneumatic tires, such as wear resistance, cornering characteristics, and ride comfort characteristics, are in a conflicting relationship with the former two, and in conventional tires with radial structure, ride comfort characteristics are considered unavoidable, and at best, The main measure to improve ride comfort was simply to sort tires according to the degree of uniformity irregularity during tire manufacturing inspections, and to delete or correct tires as necessary.

This invention advantageously improves the riding comfort of radial tires by effectively absorbing and attenuating vibrations caused by impacts applied to the tread portion, which has extremely high rigidity, using the sidewalls.

That is, this invention provides a tire that includes a cylindrical tread portion and a pair of sidewalls that extend radially inward from both ends of the tread portion and form a bead portion at the tip, and is reinforced with a radial carcass between the bead portions. , a rubber layer having a resilience in the range of 20φ to 50mm is disposed in the flex zone between the bead portion and the tread portion of the sidewall in close contact with the outside of the carcass. A comfortable pneumatic radial tire for passenger cars.

This will be explained below based on the drawings.

The figure is a cross-sectional view showing the left half of the tire according to this invention.

In the figure, a tire 1 has a cylindrical tread 2 at its center.
, continues from the tread end to the sidewall 3, forms a shoulder S1 close to the tread 2, and a bead portion 4 on the radially inner side.

Of course, the tire 1 is symmetrical with respect to the equatorial plane 0-OK.

Each of the above groups of tires is reinforced with a carcass 5 consisting of a fiber cord known as polyester or the like and rubberized plies arranged in a direction substantially perpendicular to the equatorial plane 0-0, that is, in the radial direction. is rolled up toward the outside of the tire, and a folded back 5' is provided.

In the figure, the carcass 5 has one ply, and its folded end extends at approximately the center position 1 of the cross-sectional height H of the tire, and the carcass 5 has a tapered shape surrounded by a cord layer extending from above the bead wire 6 to the tip of the folded layer 5'. An example is shown in which a special hard rubber filler I is provided to fill the space to strengthen the bead portion 4.

The tread position on the carcass is determined by the conventional method according to its width.
Non-stretchable cord such as metal is 100~
It is reinforced with a belt layer in which multiple layers are arranged at a small angle of 25 degrees and stacked one on top of the other so that the layers intersect in different directions.

The periphery of the cord reinforcing layer formed in this way is covered with outer rubber 9
Cover with

As shown in the figure, the outer covering rubber 9 has a tread rubber 9-1 which has high wear resistance and skid resistance in the part that comes into contact with the road surface during running.
In addition, the sidewall is usually made of rubber layers with different properties, such as Side Rubber 9-2, which is highly flexible and has high resilience, and Rubber Chafer 9-3, which is hard and has excellent abrasion resistance. .

Now, the tire according to this invention has a flex zone FK of the sidewall sandwiched between the upper end of the rubber filler 7 buried in the bead part for the purpose of strengthening rigidity and the shoulder S, and the resilience is 20% to 50%. In the illustrated example, a rubber layer 10, which has significantly lower resilience than the rubber material normally used for tires, is formed into a sheet and is closely attached to the outside of the carcass and embedded inside the outer cover rubber.

In the inventors' experiments, the width W measured in the radial direction of the rubber layer 10
A particularly remarkable effect was obtained when the tire height H was at least 30 mm.

In the illustrated example, the arrangement width W is 65% of the tire height H over most of the sidewall from the position of the shoulder S near the belt layer 8 to the vicinity of the bead wire 6.

The upper part of this rubber layer 10 is sandwiched between the tread rubber 9-1 and the carcass 5, and the lower part is sandwiched between the rubber filler I and the carcass 5.

This rubber layer 10 is made by thinning the side rubber 9-2 by the thickness of the rubber layer 10, preferably a thin gauge of 0.2 to 3.0 m +++, as shown in the figure, and the total thickness of the side rubber 9-2 is reduced by the thickness of the conventional side rubber. Although the entire thickness of the side rubber 9-2 has been shown as an example, the entire side rubber 9-2 may be replaced with a low resilience rubber such as the one described above.

Further, when the rubber layer 10 is formed into a relatively thin sheet and is buried inside the side rubber 9-2 as in the illustrated example, the lower part of the rubber layer 10 is formed of a rubber filler T and a carcass fold 5.
' or between the carcass fold 5' and the side rubber 9-2.

Further, a sheet-like rubber layer 1 is formed over the entire carcass 5.
It is also possible to apply a coating of 0.

Test results (axial force fluctuation measurement) 1. Tire type size: 165S, R13 (common) note: Tire B-D is the size Total gauge of rubber layer and rubber layer 10 ( 1.0+1.5) is the same as the conventional product.

2. Test method (1) Rim: 43AJ (2) Internal pressure and load: JIS standard (3) Drum: Diameter 2rIrIn surface smooth, a protrusion with a trapezoidal cross section with a height of 9.5rran fixed at one location on the circumference (4) On the drum Add a load and fix the tire shaft in that state.

When driving over a bump, the axial force applied to the tire shaft is recorded and its fluctuation (maximum amplitude of the waveform) is measured.

3゜Measurement results Note) Larger numbers are better Note: Average of data obtained at low speed range - 30, 35, 40, 45, 50 Km/h High speed range - obtained at 60, 70, 80, 90, 1100 Km/h The data averages shown in the table above show that the vertical direction is significantly improved in the low speed range, and the longitudinal direction is significantly improved in the high speed range.

(Excellent B≧C>D>A poor) Although numerical values are not listed, the diamond of the present invention also significantly shortens and improves the decay time of the axial force.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a tire showing an embodiment of this invention. 2... Tread, 3... Sidewall, 5... Carcass, 10... Rubber layer, F... Flex zone.

Claims (1)

[Claims for Utility Model Registration] A tread comprising a cylindrical tread portion and a pair of sidewalls extending radially inward from both ends of the tread portion and forming a bead portion at the tip, and reinforced with a radial carcass between the bead portions. In the tire, a rubber layer having a resilience in the range of 20 to 50% is disposed in close contact with the outside of the carcass at least in the flex zone sandwiched between the bead and tread of the sidewall. A pneumatic radial tire for passenger cars with a comfortable ride.