JP2018090102A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent air leakage and rim displacement on a bead base surface. SOLUTION: In addition to the inner region of a bead base surface 5, a rim slip prevention portion composed of a plurality of concave portions 9 or convex portions extending in the tire width direction and juxtaposed in the tire circumferential direction is formed. [Selection diagram] Fig. 1

Description

  The present invention relates to a pneumatic tire.

2. Description of the Related Art Conventionally, a pneumatic tire is known in which a bead base surface is provided with a rim slip prevention protrusion extending in an inclined manner with respect to the tire circumferential direction (see, for example, Patent Document 1).
Another pneumatic tire is known in which a plurality of ridges extending in the tire axial direction are formed on the bead base surface in the tire circumferential direction (see, for example, Patent Document 2).
Further, another pneumatic tire is known in which a bead base surface is formed with a recess that is discontinuous in the tire circumferential direction and does not connect the bead toe and the bead heel (see, for example, Patent Document 3).

  However, in any of the pneumatic tires described above, there is no consideration for air leakage and rim removal on the bead base surface in the tire width direction.

JP 2002-19427 A JP 2003-170712 A JP 2002-211115 A

  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.

As a means for solving the above problems, the present invention provides:
Provided is a pneumatic tire characterized in that, in addition to the inner region of the bead base surface, a rim displacement prevention portion is formed which includes a plurality of recesses or protrusions extending in the tire width direction and arranged in parallel in the tire circumferential direction. .

  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, rim displacement can be prevented by a concave portion or a convex portion formed outside the inner region of the bead base surface.

  The inner region preferably ranges from a bead toe on the bead base surface to a length of 5% to 15% of the bead base width.

  With this configuration, it is possible to ensure a sufficient area against air leakage in the inner region that is in surface contact with the rim.

  It is preferable that the rim deviation preventing portion is a groove portion.

  With this configuration, an edge formed by the groove portion acts on the rim in the tire circumferential direction to prevent rim displacement. Further, since only a groove is provided on the bead base surface, almost no gap is formed in the tire width direction, and no air leakage occurs.

  The groove part preferably has a bent part.

  With this configuration, it is possible to increase the length of the edge formed by the groove, and it is possible to further prevent rim displacement and air leakage.

  The groove is preferably arranged so as to form a polygon within the bead base surface.

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

  According to the present invention, no rim displacement prevention portion is formed in the inner region of the bead base surface, and the entire inner region can be brought into contact with the rim, so that air leakage can be effectively prevented. . In addition, since the rim deviation preventing portion is formed outside the inner region of the bead base surface, it is possible to prevent rim deviation during traveling, particularly during braking.

It is a schematic sectional drawing of the tire meridian direction which shows the bead core side of the pneumatic tire concerning this embodiment. It is the top view which looked at the bead base surface shown in FIG. FIG. 2 is a cross-sectional view taken along line AA of the groove shown in FIG. 1. It is the top view which looked at the bead base surface concerning other embodiments from arrow A. It is the top view which looked at the bead base surface concerning other embodiments from arrow A. It is the top view which looked at the bead base surface concerning other embodiments from arrow A. It is the top view which looked at the bead base surface concerning other embodiments from arrow A. It is the top view which looked at the bead base surface concerning other embodiments from arrow A. It is the top view which looked at the bead base surface concerning other embodiments from arrow A. It is the top view which looked at the bead base surface concerning other embodiments from arrow A.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In the following description, terms indicating specific directions and positions (for example, terms including “up”, “down”, “side”, “end”) are used as necessary. Is for facilitating understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Further, the following description is merely illustrative in nature 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 a bead core 2 side of a pneumatic tire (hereinafter, simply referred to as “tire 1”) according to the present embodiment. Here, the illustration of the internal configuration of the tire 1 other than the bead core 2 is omitted. A surface that contacts the contact receiving surface 4 of the rim 3 of the tire 1 is a 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 an arrow A (a direction along a perpendicular extending from the bead core 2 to the bead base surface 5). The bead base surface 5 is an area from the bead toe 6 to the bead heel 7 constituted by an inner peripheral surface connected in the tire circumferential direction. The bead base surface 5 includes an inner region 8 where nothing is formed (indicated by a two-dot chain line in FIG. 2) and an outer region 10 where a plurality of other recesses, that is, grooves 9 are formed. Yes.

  The inner region 8 is a flat surface and is configured to be able to come into 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 a range of 5% to 15% of the bead tow 6 to the bead base width BW. Is preferred. 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, it is possible to reliably prevent air leakage from the inside of the tire 1 by this contact area. Further, the formation range of the groove 9 described later is not narrowed, and the effect of preventing rim deviation is not impaired.

  In this case, it is preferable that the inner region 8 is positioned so as not to overlap the bead core 2 when the bead base surface 5 is seen through from the arrow A (plan projection view). According to this, since the lower part of the bead core is at a position where the pressure is increased with respect to the rim, the effect of preventing the rim from shifting is not impaired unless they overlap.

  A plurality of grooves 9 are formed in the bead base surface 5. The groove portion 9 is a straight line 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. Each groove portion 9 can freely set a groove depth D, a groove width W, and a groove interval P in the tire circumferential direction from the surface of the bead base surface 5. However, the groove width W is preferably sufficiently smaller than the groove length L, and is preferably formed so that the groove width becomes zero by being pressed against the bead base surface 5. And the edge part 11 obtained by forming the groove part 9 should just exhibit the function which press-contacts to the contact receiving surface 4 of the rim | limb 3, and prevents a shift | offset | difference. The groove 9 can be formed in various patterns shown in FIGS. 2, 4, 5, and 6.

In FIG. 2, the inner region 8 is in the range of 10% length from the bead toe 6 to 5% to 15% of the bead base width BW.
In FIG. 4, the inner region 8 ranges from the bead toe 6 to a length of 50% of the bead base width BW.
In FIG. 5, the inner region 8 ranges from the bead toe 6 to a length of 20% of the bead base width BW. In addition, the outer region 10 also has a range of 20% of the bead base width BW on the inner side from the bead heel 7 as a region where the groove portion 9 is not formed.
In FIG. 6, the groove 9 is formed from the bead toe 6 to the bead heel 7 so as to cross the bead base surface 5. That is, the inner region 8 is not formed.

  The groove portion 9 is not limited to a straight shape, and may have various shapes that can increase the length of the edge portion 11 such as a sawtooth shape as shown in FIG. it can. According to this, the length of the edge part 11 formed by the groove part 9 can be lengthened, and the rim deviation | shift prevention effect to a tire peripheral direction can be heightened. In addition, there is an effect of preventing the rim from coming off by suppressing the displacement of the tire 1 with respect to the rim 3 in the direction other than the tire circumferential direction.

  The groove portions 9 are 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 to form the groove portions 9 constituting each side so as not to communicate with each other. According to this, prevention of deviation of the tire 1 with respect to the rim 3 can be exhibited not only in the tire circumferential direction but also in various directions.

  Thus, by arranging the groove portion 9 in a polygonal shape, the edge portion 11 constituting the groove portion 9 effectively acts on the force from various directions acting on the tire 1 from the road surface, and the contact of the rim 3 is achieved. Positional displacement with respect to the contact surface 4 can be effectively prevented.

About the tire 1 which concerns on a comparative example and an Example, the rim shift | offset | difference prevention performance and the air leakage prevention performance were evaluated by the index | exponent, with the case of a comparative example being set to 100, respectively.
Regarding the rim displacement prevention performance, the braking test was repeated 10 times at a speed of 50 km / h, and the result of measuring the displacement amount of the tire 1 with respect to the rim 3 was evaluated.
Regarding air leakage prevention performance, after assembling the rim, it was left statically at room temperature for 90 days to evaluate the reduced internal pressure.

  The layout of the groove 9 is as 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 for the others. The groove width was 2.0 mm in Example 3 and 1.0 mm for the others. The groove spacing was 5.0 mm in Example 4 and 3.0 mm for the others.

  As described above, by setting the groove depth to 1.0 mm, the degree of deformation of the edge portion 11 with respect to the abutment receiving surface 4 of the rim 3 can be made the most appropriate and displacement can be effectively prevented. By setting the groove depth in the range of 0.4 mm to 1.0 mm, an effect of preventing rim displacement can be expected. In addition, the rim displacement prevention performance deteriorates as the groove width and the groove interval are increased. Even when the groove width is 2.0 mm or less and the groove interval is 5.0 mm or less, the effect of preventing rim displacement can be expected.

  In addition, this invention is not limited to the structure described in the said embodiment, A various change is possible.

  In the above-described embodiment, the different forms of the groove portion 9 have been described as examples of the concave portion of the rim displacement prevention portion. For example, by adopting a convex portion instead of the concave portion in each of the above embodiments, the edge portion of the convex portion acts on the contact receiving surface 4 of the rim 3 and effectively prevents the displacement of the tire 1 with respect to the rim 3. be able to.

DESCRIPTION OF SYMBOLS 1 ... Tire 2 ... Bead core 3 ... Rim 4 ... Abutting receiving surface 5 ... Bead base surface 6 ... Bead toe 7 ... Bead heel 8 ... Inner area | region 9 ... Groove part 10 ... Outer area | region 11 ... Edge part

Claims (5)

  A pneumatic tire characterized in that, in addition to the inner region of the bead base surface, a rim displacement prevention portion is formed which includes a plurality of concave portions or convex portions extending in the tire width direction and arranged in parallel in the tire circumferential direction.   2. The pneumatic tire according to claim 1, wherein the inner region has a length ranging from 5% to 15% of a bead base width from a bead toe of the bead base surface.   The pneumatic tire according to claim 1, wherein the rim deviation prevention portion is a groove portion.   The pneumatic tire according to claim 3, wherein the groove portion has a bent portion.   The pneumatic tire according to claim 3 or 4, wherein the groove is arranged to form a polygon in a bead base surface.

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