JPH06219106A - Pneumatic tire - Google Patents

Abstract

PURPOSE:To reduce load noise by changing a shape of a belt and an arrangement structure, and heightening rigidity of a shoulder part of the belt. CONSTITUTION:In a pneumatic tire provided with belt layers 1B and 2B having a rubberized cord in a crown part of a carcass 3 which is extended in a toroidal shape between a pair of beads 2 and 2 and is locked by being wound up outside in the axial direction of the beads 2 and 2, a distance between the carcass 3 and the first belt layer 1B among the belt layers 1B and 2B is formed narrower on the width directional end than the central part in the width direction of a tire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire for reducing vehicle interior noise, that is, road lois, by controlling tension of a shoulder portion of a belt.

[0002]

2. Description of the Related Art Conventionally existing road noise reduction methods include (1) a method of using a low modulus rubber as a tread rubber for a tire, and (2) a layer added to a shoulder portion of a tire. Then, there is a method of increasing the rigidity of the shoulder portion, and (3) a method of reducing the side tension by changing the carcass shape of the tire.

[0003]

[Problems to be Solved by the Invention] However, (1)
In the method of softening the tread rubber using a low modulus rubber as the tread rubber of the tire of (1), it adversely affects wear and the like, and the steering stability is also deteriorated, which has an adverse effect. In the method of adding a layer or the like to the portion to increase the rigidity of the shoulder portion, the addition of the layer or the like not only increases the tire weight, but also adversely affects the fuel consumption and the like, and the cost burden increases. Furthermore, the method (3) of reducing the side tension by changing the carcass shape of the tire has a problem that the steering stability is adversely affected. The present invention was devised in order to solve the problems that cannot be solved by the conventional techniques as described above, and reduces the road noise by changing the shape and arrangement of the belt and increasing the rigidity of the shoulder of the belt. The purpose is to plan.

[0004]

In order to achieve the above object, in a pneumatic tire of the present invention, a crown portion of a toroidal carcass is wound between a pair of beads and axially wound outward of the beads to be locked. In a pneumatic tire having a belt layer in which cords are rubberized, a distance between the belt layer and the carcass is narrower at a widthwise end than at a widthwise center.

[0005]

In general, a pneumatic tire has lower rigidity in the shoulder portion in the tread portion than in the vicinity of the tire equatorial plane. Therefore, it is well known that the shoulder portion is reinforced in order to increase the bending rigidity of the entire tread portion, and thereby the durability is improved and the steering stability is improved. However, from the viewpoint of reducing road noise, few improvements have been made. As a method of increasing the rigidity of the belt in the circumferential direction in order to reduce road noise, there is a method of increasing the tension, but normally it is desirable to arrange the belt angle in parallel with the circumferential direction. However, if the belt angle is made closer to the circumferential direction, the belt edge separation is likely to be adversely affected.

Therefore, the inventor of the present invention has found that in the stress distribution of the tread portion, the tire ground contact side is a compression region,
Since the side closer to the carcass is the tension region, the belt radius is changed by changing the radius of curvature R of the belt in FIG. 1 by focusing on increasing the tension by keeping the belt end away from the compression region and arranging it in the tension region. , I thought about the method of controlling the tension. That is, it was confirmed that the smaller the radius of curvature R of the belt, the shorter the circumferential length of the shoulder portion at the time of contact with the ground and the more the belt tension in the circumferential direction can be increased. As a method for this, a radius of curvature R is locally changed by inserting a rubber layer 7 having a width narrower than that of the first belt 1B between the carcass and the first belt 1B, and the first belt on the equatorial plane and the shoulder portion is changed. And carcass height ratio (AH / BH)
2 was produced by manufacturing a structure in which was changed from 0.5 to 2.0 in steps of 0.1, and the tension was calculated. It was found that the AH / BH was 1.0 or more, and the tension in the shoulder circumferential direction sharply increased.

Therefore, when AH / BH was changed from 1.0 to 2.0 in 0.1 steps and the sound inside the vehicle was measured,
When / BH is 1.3, it can be confirmed that the vehicle interior noise can be reduced by 0.5 dB or more as compared with the conventional control tire, and as a result, the critical value of the difference felt by the occupant as feeling is 0.5 dB. Since it was confirmed that when AH / BH> 1.3, road noise was remarkably reduced.

[0007]

Embodiments will be described below with reference to the drawings. 3 is a sectional view of a control tire showing a conventional example, FIG. 4 is a sectional view showing Example 1 of the present invention, FIG. 5 is a sectional view showing Example 2 and FIG. 6 is a sectional view showing Example 3. It is a figure. In the conventional pneumatic tire shown in FIG. 3, a toroidal carcass 3 is bridged between a pair of left and right beads 2 and 2, and the carcass 3 is wound up and locked to the outside of the beats 2 and 2 in the axial direction. Filler 4 at the top of the bead
4 is provided, and the wound carcass 3 is stopped near the upper end thereof. A first belt 1B and a second belt 2B are arranged on the upper surface side of the carcass 3 of the crown portion 5 to form a tread portion 6.

The pneumatic tire of Example 1 of the present invention shown in FIG. 4 is provided with beads 2, 2 and fillers 4, 4, and a toroidal carcass 3 is stretched between a pair of left and right beads 2, 2. The carcass 3 has exactly the same structure in that it is rolled up to the outside of the bead in the axial direction and is locked around the fillers 4, 4. A first belt 1B and a second belt 2B are arranged above the carcass 3 of the crown portion 6, and a belt cushion rubber layer 7 having a predetermined width is interposed in the central portion between the carcass 3 and the first belt 1B. is doing. At the end of the cushion rubber layer 7 under the belt, the first belt 1B and the second belt 2B are arranged so as to be bent so as to approach the carcass 3 at the shoulder portion 8.

In order to bend the first belt 1B and the second belt 2B, a hard rubber 9 may be further inserted on the upper surface side of the second belt 2B to bend the belts 1B and 2B. In this way, the rigidity of the belt, particularly the rigidity of the shoulder portion, is increased. At that time, the distance between the carcass 3 and the first belt 1B on the equatorial plane C is AH,
Assuming that the distance between the carcass 3 at the end of the belt 1B and the first belt 1B is BH, AH / BH> 1.
Needless to say, it is selected as shown in FIG. Next, in the second embodiment shown in FIG. 5, unlike the first embodiment, the belt lower cushion rubber layer 7 interposed between the carcass 3 and the belt 1B has the maximum thickness at the equatorial plane C and then goes outward. According to the above, the lower belt cushion rubber layer 7 has a wing-shaped cross-sectional shape composed of a line gently curving and a horizontal line on the lower surface.
The distance AH between B and the carcass 3 at the end of the first belt 1B
And the distance BH between the first belt 1B and AH / BH is AH
/BH>1.3.

In the third embodiment shown in FIG. 6, the lower belt cushion rubber layer 7 is composed of a ring-shaped rubber layer having a semicircular cross section, one on the equator plane C, and a space on the left and right thereof. They are arranged one by one on the upper side of the carcass 3, and on the upper side thereof, a first belt 1B and a second belt 2B are provided in a wave shape between the lower belt cushion rubber layer 7,
Similarly to the above, the distance AH between the carcass 3 and the first belt 1B and the carcass 3 and the first belt 1B at the end of the first belt 1B.
AH / BH, which is the ratio to the distance BH, is designed to be greater than 1.3. The under-belt cushion rubber layer described above may have any cross-sectional shape such as a plate-like or semi-circular shape as long as it is made of similar hard rubber.

Next, the above-mentioned conventional example (FIG. 3) and Example 1
(Fig. 4) Tire configuration 195 / 65R tire size
The specific structures and materials applied to the tires of No. 14 are shown, and the test results of the test tires of the conventional example and the example mounted on an actual vehicle and traveling on a road noise road are as follows. (I) Material Structure of Tire (1) Example 1 Carcass: One layer of nylon cord Belt: Steel cord 20 with respect to tire equatorial plane C
Inclination is made to be a two-layer cross lamination. (2) Conventional example Carcass: One layer of nylon cord Belt: Steel cord 20 with respect to tire equatorial plane C
Inclination is made to be a two-layer cross lamination. (II) Test conditions An actual vehicle equipped with test tires was driven at a speed of 60 Km / h on a road noise road with a large number of protrusions having an average height of 5 mm. (III) Test result

[0012] Vehicle interior sound: The vehicle interior sound of the conventional example is controlled to 0 dB, and AH / BH of the first embodiment is 1.3, 1.5, 2.0 based on that control.
The inside sound of an actual vehicle equipped with the tires of the above structure was measured by an instrument inside the right front vehicle. (However, AH: distance between the carcass and the first belt on the equatorial plane, BH: distance between the carcass and the first belt on the end of the first belt) From the above results, in Example 1, three different belt structure design examples It was found from the test of 1. that the vehicle interior noise can be significantly reduced by increasing the tension of the tire shoulder portion.

[0014]

As described in detail above, since the present invention is constituted, the distance between the belt layer and the carcass is made narrower at the widthwise end than at the tire widthwise central portion, so that the tire shoulder portion The tension can be increased, and as a result, road noise can be reduced without impairing steering stability.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of changing a radius of curvature R of a tire belt.

FIG. 2 is a diagram showing the relationship between the ratio of the distance AH between the carcass and the first belt on the equatorial plane of the tire and the distance BH between the carcass and the first belt at the end of the first belt, and the tension in the circumferential direction of the shoulder portion.

FIG. 3 is a cross-sectional view of a conventional pneumatic tire.

FIG. 4 is a cross-sectional view of the pneumatic tire showing the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of a pneumatic tire showing a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a pneumatic tire showing a third embodiment of the present invention.

[Explanation of symbols]

 1 pneumatic tire 2 bead 3 carcass 4 filler 5 crown part 6 tread part 7 belt lower cushion rubber layer 8 shoulder part 1B 1st belt 2B 2nd belt

Claims (1)

[Claims] 1. A pneumatic tire having a belt layer with a cord rubberized on a crown portion of a toroidal carcass wound between the pair of beads and axially outwardly wound on the bead, wherein the belt layer and the carcass are provided. The pneumatic tire is characterized in that the distance to the widthwise end is narrower at the widthwise end than at the widthwise central portion.