阅读说明：本技术 充气轮胎 (Pneumatic tire ) 是由 藤冈刚史 于 2019-06-11 设计创作，主要内容包括：技术问题：即使在胎肩肋形成封闭切槽的情况下,也有效地防止嵌石。解决方案：充气轮胎具备：沿轮胎周向延伸的多条主槽(5)、以及通过主槽(5)中的胎肩主槽(7)而形成于轮胎宽度方向外侧的胎肩肋(14)。胎肩肋(14)具有与胎肩主槽(7)连通并且在胎肩肋(14)内结束的封闭切槽(16)。在胎肩主槽(7)形成有在封闭切槽(15)内延伸的突起(19)。(The technical problem is as follows: even in the case where the shoulder ribs form the closing cut grooves, stone trapping is effectively prevented. The solution is as follows: a pneumatic tire is provided with: a plurality of main grooves (5) extending in the tire circumferential direction, and shoulder ribs (14) formed on the outer side in the tire width direction by shoulder main grooves (7) in the main grooves (5). The shoulder rib (14) has a closure groove (16) which communicates with the shoulder main groove (7) and ends within the shoulder rib (14). A protrusion (19) extending in the closed groove (15) is formed in the shoulder main groove (7).)

1. A pneumatic tire is provided with:

a plurality of main grooves extending in a tire circumferential direction; and

a shoulder rib formed on the outer side in the tire width direction through a shoulder main groove among the main grooves,

the shoulder rib has a closure cut groove communicating with the shoulder main groove and ending within the shoulder rib,

in the shoulder main groove, a protrusion extending in the closing groove is formed.

2. A pneumatic tire according to claim 1,

the tip of the protrusion within the closure slot is formed at an acute angle.

3. A pneumatic tire according to claim 1 or 2,

the projection has a bifurcated tip portion located within the enclosed slot.

4. A pneumatic tire according to any one of claims 1 to 3,

the protrusion has a plurality of sharp end portions formed at acute angles.

5. A pneumatic tire according to claim 4,

the shoulder main groove is provided with a protruding strip which divides the bottom surface along the length direction,

the tip of the protrusion protrudes toward at least one of the portions divided by the protrusion.

6. A pneumatic tire according to any one of claims 1 to 5,

the protrusions are formed in a star shape having five pointed ends formed at acute angles.

Technical Field

The present invention relates to a pneumatic tire.

Background

Conventionally, there is known a pneumatic tire in which a stone-trapping preventing ridge is provided at an intersection of a circumferential groove and a lateral groove (see, for example, patent document 1).

In the pneumatic tire, a closed cut groove is formed in the shoulder rib from the shoulder main groove side in order to improve traction performance. Therefore, a recess that is expanded compared to the other portions is formed at the shoulder main groove and the closing cut groove. Therefore, there is a problem that stones are easily embedded in the recess.

Disclosure of Invention

Technical problem to be solved

The present invention addresses the problem of providing a pneumatic tire that can effectively prevent stone entrapment even when shoulder ribs form closed cuts.

(II) technical scheme

As means for solving the above problems, the present invention provides a pneumatic tire comprising: a plurality of main grooves extending in a tire circumferential direction; and a shoulder rib formed on the outer side in the tire width direction through a shoulder main groove of the main grooves, the shoulder rib having a closed cut groove communicating with the shoulder main groove and ending in the shoulder rib, and a protrusion extending in the closed cut groove being formed in the shoulder main groove.

With this configuration, when the shoulder main groove is grounded, the projection extending from the shoulder main groove into the closed cut groove is elastically deformed, and even if a stone is fitted into the closed cut groove, the stone can be surely discharged.

Preferably, a tip portion of the protrusion located within the closing slot is formed at an acute angle.

With this configuration, when the ground is grounded, the tip of the elastically deformed protrusion can be used to intensively apply a force to the stone fitted into the closed slit, and therefore, the fitted stone can be easily discharged.

Preferably, the projection has a bifurcated tip portion located within the closure slot.

With this configuration, the force of the two pointed ends can be applied to the stone fitted into the closed slit at the time of grounding, and therefore, the stone can be further easily discharged.

Preferably, the protrusion has a plurality of sharp end portions formed at acute angles.

With this configuration, not only the stones fitted into the closed slits but also the stones fitted into the peripheral region thereof can be discharged effectively.

Preferably, the shoulder main groove includes a ridge dividing a bottom surface in a longitudinal direction, and a tip end of the protrusion protrudes toward at least one of the ridge.

Preferably, the protrusion is formed in a star shape having five pointed ends formed at acute angles.

(III) advantageous effects

According to the present invention, since the protrusions extending from the shoulder main groove into the closing cut groove formed in the shoulder rib are formed, the protrusions are deformed when grounding, and the embedded stones can be effectively discharged.

Drawings

Fig. 1 is a schematic view of a radial half-section of a pneumatic tire according to the present embodiment.

Fig. 2 is a partially developed view of the tread portion shown in fig. 1.

Fig. 3 is a partially enlarged view showing the first closing incision of fig. 2.

Fig. 4 is a partially enlarged perspective view illustrating the second closing incision of fig. 2.

Description of the reference numerals

1-a tire; 2-a tread portion; 3-sidewall portions; 4-bead portion; 5-a main tank; 6-central main groove; 7-shoulder main grooves; 8-a central rib; 9-wide grooving; 10-a block; 11-narrow grooving; 12-a first small block; 13-a second small block; 14-shoulder ribs; 15-a first closing incision; 16-a protrusion; 17-a protrusion; 18-a first protrusion; 19-a second protrusion; 20-ribs; 21-a first tip portion; 22-a second tip portion; 23-a third pointed end; 24-a fourth tip portion; 25-a fifth tip portion; 26-a second closure slot; 27-a transverse slot; 28-a first kerf portion; 29-second kerf portion.

Detailed Description

Embodiments of the present invention are described below with reference to the drawings. The following description is merely exemplary in nature and is not intended to limit the present invention, its applications, or uses.

Fig. 1 is a schematic view of a radial half-section of a pneumatic tire 1 (hereinafter referred to as a tire 1) according to the present embodiment. The tire 1 includes: a tread portion 2 that contacts a road surface, a sidewall portion 3 that extends inward in the tire radial direction from the tread portion 2, and a bead portion 4 that extends inward in the tire radial direction from the sidewall portion 3 and is attached to a rim, not shown.

Fig. 2 is a partially developed view of the tread portion 2 shown in fig. 1. A plurality of (here, three) main grooves 5 extending in the tire circumferential direction CD are formed in the tread portion 2. One of the central portions is a central main groove 6, and two of the both sides are shoulder main grooves 7. Each main groove 5 is formed in a zigzag shape.

A center rib 8 is formed by the center main groove 6 and the shoulder main groove 7. Each center rib 8 is formed with wide slits 9 extending obliquely in the tire width direction WD at predetermined intervals in the tire circumferential direction CD. The wide slits 9 are set to have smaller width and depth dimensions than the main slits 5. Each of the center ribs 8 is a block row composed of a plurality of blocks 10 by the wide notches 9. Each block 10 is divided into a first small block 12 and a second small block 13 having a hexagonal shape by a narrow slit 11. The narrow slits 11 are set smaller in width and depth than the wide slits 9. Of the two center ribs 8, the first block 12 and the second block 13 are in an opposite positional relationship in the tire circumferential direction CD.

Shoulder ribs 14 are formed on both sides in the tire width direction WD that are defined by the shoulder main grooves 7. The shoulder main groove 7 is composed of a first shoulder main groove portion 7a extending obliquely downward to the left in fig. 2, and a second shoulder main groove portion 7b extending obliquely downward to the right. In the shoulder rib 14, the first closed cut groove 15 extends from a position protruding outward in the tire width direction WD in a region where the first shoulder main groove portion 7a and the second shoulder main groove portion 7b intersect. The first closed cutting grooves 15 are provided at a prescribed pitch in the tire circumferential direction CD. The first closed cut groove 15 corresponds in position in the tire circumferential direction CD to a corner portion that protrudes most toward the shoulder main groove 7 among the corner portions of the block 10.

With reference to fig. 3, the shoulder rib 14 on the right side in fig. 2 will be described. Note that, the shoulder rib 14 on the left side has the same configuration except that the shoulder rib 14 on the right side is rotated by 180 ° about any one of the center positions in the tire width direction WD, and therefore, the description thereof is omitted.

Between the first closed cut grooves 15, a protrusion 16 protruding toward the shoulder main groove 7 is formed. The edge portion defining the protruding portion 16 includes a first inclined edge 16a and a second inclined edge 16 b. The first inclined edge 16a extends obliquely downward to the left. (here, inclined by about 22 ° with respect to a straight line extending in the tire circumferential direction CD). The second inclined edge 16b extends obliquely downward to the right (here, inclined by about 15 ° with respect to a straight line extending in the tire circumferential direction CD).

The first closed cut groove 15 is formed between the first protrusion 16A and the second protrusion 16B arranged in the tire circumferential direction CD. The first closed slit 15 is a region surrounded by the three edges 15a, 15b, 15c and the imaginary line 15 d. The first edge 15a is inclined at a further increased inclination angle with respect to the second inclined edge 16b of the first projection 16A. The second edge 15B is inclined so as to extend in the tire width direction WD from the first inclined edge 16a of the second protrusion 16B. The third edge 15c connects the first edge 15a and the second edge 15B, and is parallel to the first inclined edge 16a of the second projection 16B. The imaginary line 15d is a straight line (indicated by a two-dot chain line in fig. 3) connecting an intersection point n1 of the second inclined edge 16b and the first edge 15a and an intersection point n2 of the second edge 15b and the first inclined edge 16 a.

A plurality of protrusions 17 are formed at the groove bottom of the shoulder main groove 7. The protrusion 17 is composed of a first protrusion 18 formed on the center line of the shoulder main groove 7 and a second protrusion 19 extending from the shoulder main groove 7 toward the first closing incision 15.

The first protrusion 18 is formed in a substantially parallelogram shape in a plan view on the center line of the shoulder main groove 7. Two shoulder main grooves 7a and two shoulder main grooves 7b are disposed in the shoulder main groove 7. The first protrusion 18 has a rounded corner chamfered, and a rib 20 extends from the center toward the inner surface of the sidewall constituting the shoulder main groove 7. Although not shown, the inner surface of the side wall constituting the shoulder main groove 7 is formed of a tapered surface inclined toward the center line side toward the groove bottom. The rib 20 extends to the tapered surface on the opposite side in the first shoulder main groove portion 7a and the second shoulder main groove portion 7 b.

The second protrusion 19 is star-shaped in plan view, and extends from the shoulder main groove 7 into the first closed cut groove 15. The second projection 19 has a tip portion that is triangular in five places around and projects at an acute angle. The portion projecting into the first closed slot 15 is constituted by a first point 21 and a second point 22 divided into two prongs. The first tip portion 21 extends toward a first corner portion 15x where the first edge 15a and the third edge 15c of the first closing slit 15 intersect. The second tip portion 22 extends toward the second corner portion 15y where the second edge 15b intersects the third edge 15 c. In addition, the third pointed end portion 23 extends toward a space between the first protrusion 18 formed in the first shoulder main groove portion 7a and the shoulder rib 14. The fourth tip portion 24 extends towards the space between the first projection 18 and the central rib 8. The fifth peak portion 25 extends toward the first protrusion 18 formed at the second shoulder main groove portion 7 b.

As shown in fig. 2, the shoulder rib 14 has a second closed cut groove 26 and a lateral groove 27 formed in the outer edge portion in the tire width direction WD. The second closed cutting grooves 26 and the lateral grooves 27 are alternately arranged in the tire circumferential direction CD.

As shown in fig. 4, the second closing slit 26 is composed of a first slit portion 28 and a second slit portion 29, the first slit portion 28 is formed as a tapered surface whose width dimension gradually decreases from the surface of the shoulder rib 14, and the second slit portion 29 is formed as a narrow groove continuous to the first slit portion 28. That is, the second closed incision 26 is formed in a Y shape as a whole.

As shown in fig. 2, the second closed cut groove 26 extends from the outer edge of the shoulder rib 14 inward in the tire width direction WD, and the tip thereof ends near the center of the shoulder rib 14. Moreover, a tapered surface extending in the tire width direction WD is also formed at the end position of the second closed cut 26.

In this way, the first groove 28 has a tapered surface and expands toward the outer surface, while the width of the second groove 29 is reduced, so stone trapping is easily prevented. Further, since the second groove portion 29 is formed deeply, even if the shoulder rib 14 is worn, the traction performance can be maintained.

In addition, the second closed cut groove 26 is formed at a position corresponding to the central portion of the adjacent first closed cut groove 15 in the tire circumferential direction CD. That is, the positions of the second closing slits 26 are offset in the tire circumferential direction CD with respect to the first closing slits 15. Further, the first closed cut groove 15 and the second closed cut groove 26 are arranged so as not to overlap in the tire width direction WD when viewed in the tire circumferential direction CD. That is, the end positions of the second closed cut grooves 26 are offset in the tire width direction WD with respect to the end positions of the first closed cut grooves 15 (the offset amount is represented by δ in fig. 2). This can prevent the cornering performance from being lowered while maintaining the desired rigidity of the shoulder rib 14.

According to the pneumatic tire 1 configured as described above, the center rib 8 is configured by the block row composed of the plurality of blocks 10. The main groove 5 is saw-toothed in shape. The shoulder rib 14 is also formed with a first closed groove 15 and a second closed groove 26. Therefore, the traction is excellent.

Further, the main groove 5 is formed with a first protrusion 18, and the second protrusion 19 extends in the first closed cut groove 15 extending from the shoulder main groove 7 toward the shoulder rib 14. Thus, even if stones are fitted into the main groove 5 and the first closed cut groove 15, the fitted stones can be discharged. That is, the first projection 18 and the second projection 19 are deformed at the time of grounding, and force is applied so as to discharge the embedded stones. In particular, in the second projection 19 there are a first point 21 and a second point 22, which project at an acute angle inside the first closing incision 15. Therefore, the portion projecting at an acute angle can exert a force intensively on the embedded stone. In addition, the first and second pointed portions 21 and 22 face the corners of the first closed slit 15 farthest away. Therefore, the force can be applied so as to easily discharge the embedded stones. In this way, the discharge operation can be performed efficiently.

Further, the first closing slit 15 and the second closing slit 26 formed in the shoulder rib 14 are displaced in the tire circumferential direction CD. Further, the end positions of the first closed cut groove 15 and the second closed cut groove 26 are separated in the tire width direction WD. Therefore, the traction performance of the shoulder rib 14 can be improved, and the reduction in rigidity can be prevented. Thus, cornering performance is not impaired. In particular, since the second closed cut groove 26 is formed in a Y-shaped cross section, it is difficult to fit a stone, and even if the shoulder rib 14 is worn, the traction performance is maintained by the second opening portion.

The present invention is not limited to the configuration described in the above embodiment, and various modifications are possible.

In the above embodiment, the two center ribs 8 and the two shoulder ribs 14 are provided, but the present invention is not limited thereto, and various configurations may be adopted. For example, two intermediate ribs may be provided on both sides of one center rib 8, and shoulder ribs 14 may be provided on the outer sides in the tire width direction WD.