JP6826422B2 - Pneumatic tires - Google Patents

Description

The present invention relates to a pneumatic tire.

Conventionally, as a pneumatic tire, one in which a ridge for preventing rim slippage extending in an inclined direction with respect to the tire circumferential direction is formed on a bead base surface is known (see, for example, Patent Document 1).
Further, as another pneumatic tire, a tire in which a plurality of ridges extending along the tire axial direction are formed on the bead base surface in the tire circumferential direction is known (see, for example, Patent Document 2).
Further, as another pneumatic tire, a tire in which a recess that is discontinuous in the tire circumferential direction and does not connect the bead toe and the bead heel is formed on the bead base surface is known (see, for example, Patent Document 3).

However, none of the above pneumatic tires takes into consideration air leakage in the tire width direction and rim detachment on the bead base surface.

JP-A-2002-19427 Japanese Unexamined Patent Publication No. 2003-170712 Japanese Unexamined Patent Publication No. 2002-21215

An object of the present invention is to provide a pneumatic tire that effectively prevents air leakage and rim displacement on the bead base surface.

The present invention, as means for solving the above problems, in addition to the inner region of the bi Dobesu surface, rim displacement prevention portion comprising a plurality of grooves which are arranged in the tire circumferential direction extending in the tire width directions is formed Each of the plurality of grooves is arranged so as to form a polygonal side in the bead base surface, and the adjacent grooves of the plurality of grooves are provided at intervals so as not to communicate with each other. to provide a pneumatic tire, characterized in that.

With this configuration, the inner region of the bead base surface can be brought into surface contact with the rim, and air leakage can be prevented. Further, the rim displacement can be prevented by the groove formed in the region other than the inner region of the bead base surface. Specifically, the edges formed by the grooves act on the rim to prevent rim slippage. Further, since the bead base surface is only provided with a groove portion, almost no gap is formed in the tire width direction, and no air leakage occurs. Further, since the groove portion is arranged so as to form a polygon in the bead base surface, it is possible to effectively prevent the rim displacement even when a force acts in multiple directions due to cornering or the like.

The inner region is preferably in a length range from the bead toe on the bead base surface to 5% or more and 15% or less of the bead base width.

With this configuration, a sufficient area can be secured against air leakage in the inner region that comes into surface contact with the rim.

With this configuration, even when a force acts in multiple directions in cornering or the like, rim displacement can be effectively prevented.

According to the present invention, the rim slip prevention portion is not formed in the inner region of the bead base surface, and the inner region can be brought into full contact with the rim, so that air leakage can be effectively prevented. .. Further, since the rim slip prevention portion is formed in areas other than the inner region of the bead base surface, it is possible to prevent the rim slippage during running, especially during braking.

It is a schematic cross-sectional view in the tire meridian direction which shows the bead core side of the pneumatic tire which concerns on this embodiment. It is a top view of the bead base surface shown in FIG. 1 as seen from arrow A. FIG. 5 is a cross-sectional view taken along the line AA of the groove shown in FIG. It is a top view which looked at the bead base surface which concerns on another Embodiment from the arrow A. It is a top view which looked at the bead base surface which concerns on another Embodiment from the arrow A. It is a top view which looked at the bead base surface which concerns on another Embodiment from the arrow A. It is a top view which looked at the bead base surface which concerns on a reference example from the arrow A. It is a top view which looked at the bead base surface which concerns on another Embodiment from the arrow A. It is a top view which looked at the bead base surface which concerns on another Embodiment from the arrow A. It is a top view which looked at the bead base surface which concerns on another Embodiment from the arrow A.

Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. In the following description, terms indicating a specific direction or position (for example, terms including "top", "bottom", "side", and "edge") are used as necessary, but the use of these terms is used. Is for facilitating the understanding of the invention with reference to the drawings, and the meaning of those terms does not limit the technical scope of the present invention. In addition, the following description is merely an example and is not intended to limit the present invention, its application, or its use. Furthermore, the drawings are schematic, and the ratio of each dimension is different from the actual one.

FIG. 1 is a schematic cross-sectional view in the tire meridian direction showing the bead core 2 side of the pneumatic tire according to the present embodiment (hereinafter, simply referred to as “tire 1”). Here, the internal configuration of the tire 1 is not shown except for the bead core 2. The surface of the tire 1 that comes into contact with the contact receiving surface 4 of the rim 3 is the bead base surface 5.

FIG. 2 is a plan view of the bead base surface 5 of the tire 1 shown in FIG. 1 as viewed from arrow A (direction along a vertical line extending from the bead core 2 to the bead base surface 5). The bead base surface 5 is a region from the bead toe 6 to the bead heel 7 formed by an inner peripheral surface connected in the tire peripheral direction. The bead base surface 5 is composed of an inner region 8 in which nothing is formed (indicated by a two-dot chain line in FIG. 2) and an outer region 10 in which a plurality of other recesses, that is, grooves 9, are formed. There is.

The inner region 8 is a flat surface and is configured to be in surface contact with the contact receiving surface 4 of the rim 3. Here, if the length from the bead toe 6 to the bead heel 7 is defined as the bead base width BW, the formation range of the inner region 8 is the range of the length from the bead toe 6 to the bead base width BW of 5% or more and 15% or less. Is preferable. According to this, the inner region 8 having a sufficient length in the tire width direction can be brought into surface contact with the contact receiving surface 4 of the rim 3. Therefore, this contact region makes it possible to reliably prevent air leakage from the inside of the tire 1. Further, the formation range of the groove portion 9, which will be described later, is not narrowed and the effect of preventing rim slippage is not impaired.

In this case, it is preferable that the inner region 8 is positioned so that the bead base surface 5 is seen through from the arrow A (planar projection view) and does not overlap with the bead core 2. According to this, since the lower part of the bead core is at a position where the pressure is high with respect to the rim, the effect of preventing the rim from slipping is not impaired if they do not overlap.

A plurality of groove portions 9 are formed on the bead base surface 5. The groove portion 9 has a linear shape extending in the tire width direction, and as shown in FIG. 3, the groove bottom side is formed in an arc shape having a radius R at both ends. In each groove portion 9, the groove depth D, the groove width W, and the groove spacing P in the tire circumferential direction from the surface of the bead base surface 5 can be freely set. However, it is preferable that the groove width W is sufficiently smaller than the groove length L and is formed so that the groove width becomes 0 by being pressed against the bead base surface 5. Then, the edge portion 11 obtained by forming the groove portion 9 may be brought into pressure contact with the contact receiving surface 4 of the rim 3 to exert a function of preventing deviation. Further, the groove portion 9 can be formed by various patterns shown in FIGS. 2, 4, 5 and 6.

In FIG. 2, the inner region 8 is in the range of the length from the bead toe 6 to the bead base width BW of 10 %.
In FIG. 4, the inner region 8 is a length range from the bead toe 6 to 50% of the bead base width BW.
In FIG. 5, the inner region 8 is defined as a length range from the bead toe 6 to 20% of the bead base width BW. Further, in the outer region 10 as well, a region having a length of 20% of the bead base width BW is defined as a region in which the groove portion 9 is not formed from the bead heel 7 to the inside.
In the reference example of FIG. 7 , the groove 9 is formed so as to cross the bead base surface 5 from the bead toe 6 to the bead heel 7. That is, the inner region 8 is not formed.

The groove portion 9 is not limited to a linear shape, and may have various shapes such as a sawtooth shape as shown in FIG. 6 or a corrugated shape (not shown) so that the length of the edge portion 11 can be lengthened. it can. According to this, the length of the edge portion 11 formed by the groove portion 9 can be lengthened to enhance the effect of preventing the rim from shifting in the tire circumferential direction. It also has the effect of suppressing the displacement of the tire 1 with respect to the rim 3 in directions other than the tire circumferential direction to prevent the rim from coming off.

The groove portion 9 is formed in parallel along the tire width direction, but may be formed so as to form a polygon. For example, it can be formed by a triangle shown in FIG. 8, a quadrangle shown in FIG. 9, a hexagon shown in FIG. In this case, it is preferable that the groove portions 9 forming each side are formed so as not to communicate with each other. According to this, it is possible to prevent the tire 1 from slipping with respect to the rim 3 not only in the tire circumferential direction but also in various directions.

By arranging the groove portions 9 in a polygonal shape in this way, the edge portions 11 constituting the groove portions 9 effectively act on the forces from various directions acting on the tire 1 from the road surface, and the rim 3 is hit. It is possible to effectively prevent the displacement with respect to the receiving surface 4.

For the tire 1 according to the comparative example and the example, the rim slippage prevention performance and the air leakage prevention performance were evaluated by an index with the case of the comparative example as 100.
Regarding the rim slip prevention performance, the braking test was repeated 10 times at a speed of 50 km / h, and the result of measuring the slip amount of the tire 1 with respect to the rim 3 was evaluated.
Regarding the air leakage prevention performance, after assembling the rim, it was left statically for 90 days at a constant temperature at room temperature, and the state of decrease in internal pressure was evaluated.

The layout of the groove portion 9 is shown in FIG. 2 for Examples 1 to 4, FIG. 4 for Example 5, and FIG. 5 for Example 6. The groove depth was 0.4 mm in Example 2 and 1.0 mm in the others. The groove width was 2.0 mm in Example 3 and 1.0 mm in the others. The groove spacing was 5.0 mm in Example 4 and 3.0 mm in the others.

By setting the groove depth to 1.0 mm in this way, it was possible to effectively prevent misalignment by making the degree of deformation of the edge portion 11 with respect to the contact receiving surface 4 of the rim 3 the most appropriate. By setting the groove depth in the range of 0.4 mm to 1.0 mm, the effect of preventing rim slippage can be expected. Further, the larger the groove width and the groove spacing, the worse the rim displacement prevention performance. A rim displacement prevention effect can also be expected by setting the groove width to 2.0 mm or less and the groove spacing to 5.0 mm or less.

The present invention is not limited to the configuration described in the above embodiment, and various modifications can be made.

In the above-described embodiment, a different form of the groove portion 9 has been described as an example of the concave portion of the rim displacement prevention portion, but the rim displacement prevention portion is not limited to the concave portion and may be formed by a convex portion. For example, by adopting a convex portion instead of the concave portion in each of the above-described embodiments, the edge portion of the convex portion acts on the contact receiving surface 4 of the rim 3 to effectively prevent the displacement of the tire 1 with respect to the rim 3. be able to.

1 ... Tire 2 ... Bead core 3 ... Rim 4 ... Contact receiving surface 5 ... Bead base surface 6 ... Bead toe 7 ... Bead heel 8 ... Inner area 9 ... Groove 10 ... Outer area 11 ... Edge

Claims (2)

In addition to the inner region of the bead base surface, a rim slip prevention portion composed of a plurality of grooves extending in the tire width direction and arranged side by side in the tire circumferential direction is formed .
Each of the plurality of grooves is arranged so as to form a polygonal side in the bead base surface.
A pneumatic tire characterized in that adjacent grooves among the plurality of grooves are provided at intervals so as not to communicate with each other . The pneumatic tire according to claim 1, wherein the inner region has a length ranging from the bead toe of the bead base surface to 5% or more and 15% or less of the bead base width.

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