Pneumatic tire
阅读说明:本技术 充气轮胎 (Pneumatic tire ) 是由 藤冈刚史 于 2019-06-20 设计创作,主要内容包括:技术问题:在构成为肋花纹的充气轮胎中,抑制偏磨损的产生,并且提高牵引性。解决方案:充气轮胎(1)在胎面部(2)利用沿轮胎周向延伸的多个主槽(10)形成有沿轮胎周向延伸的多个肋(20)。在多个肋(20)中的划分于轮胎宽度方向的中央部的中央肋(21)形成有从与主槽(10)连通的一端部起沿轮胎宽度方向延伸、且另一端部在所述中央肋内结束的多个第一及第二封闭槽(31、32),多个第一及第二封闭槽(31、32)以从中央肋(21)的轮胎宽度方向的两侧对置的方式形成。(The technical problem is as follows: a pneumatic tire having a rib pattern is provided with improved traction while suppressing uneven wear. The solution is as follows: a pneumatic tire (1) is provided with a plurality of ribs (20) extending in the tire circumferential direction, which are formed in a tread portion (2) by a plurality of main grooves (10) extending in the tire circumferential direction. A plurality of first and second closed grooves (31, 32) extending in the tire width direction from one end portion communicating with the main groove (10) and terminating at the other end portion in the central rib are formed in the central rib (21) that is divided in the center portion in the tire width direction among the plurality of ribs (20), and the plurality of first and second closed grooves (31, 32) are formed so as to face each other from both sides in the tire width direction of the central rib (21).)
1. A pneumatic tire having a tread portion formed with a plurality of ribs extending in a tire circumferential direction by a plurality of main grooves extending in the tire circumferential direction,
a plurality of closed grooves extending in the tire width direction from one end portion communicating with the main groove and having the other end portion terminating in the center rib are formed in the center rib that is divided into a center portion in the tire width direction among the plurality of ribs,
the plurality of closed grooves are formed so as to face each other from both sides of the center rib in the tire width direction.
2. A pneumatic tire according to claim 1,
among the ribs, a shoulder rib that is defined at an outer end in a tire width direction is formed alternately in a tire circumferential direction:
a closed groove extending in the tire width direction from one end portion communicating with the main groove, and the other end portion ending in the shoulder rib; and
and a closed groove extending in the tire width direction from one end portion communicating with the ground contact end on the outer side in the tire width direction, and the other end portion ending in the shoulder rib.
3. A pneumatic tire according to claim 2,
an intermediate rib among the plurality of ribs, which is divided between the center rib and the shoulder rib in the tire width direction, is alternately formed in the tire circumferential direction with:
a closed groove extending in the tire width direction from one end portion communicating with the main groove on the center rib side, and the other end portion ending in the intermediate rib; and
a closed groove extending in the tire width direction from one end portion communicating with the main groove on the shoulder rib side, and the other end portion ending in the intermediate rib.
4. A pneumatic tire according to claim 1 or 2,
the plurality of main grooves extend in a zigzag shape in the tire circumferential direction,
the closed groove communicating with the main groove is formed at a corner of the plurality of ribs that is divided into concave shapes in the tire width direction by the main groove.
5. A pneumatic tire according to claim 1 or 2,
a pair of closed grooves is formed in the center rib by a pair of the closed grooves opposed to each other in the tire width direction,
and a plurality of the closed groove pairs arranged in parallel in the tire width direction are formed with a connecting groove that connects the closed groove pairs in the tire width direction so as to be aligned every other in the tire circumferential direction, and the connecting groove is shallower than the closed groove.
6. A pneumatic tire according to claim 3,
a plurality of sipes extending in the tire width direction are formed in each of the plurality of ribs,
at each rib, at least the sipe longest in the tire width direction among the plurality of sipes is a 3D sipe whose shape varies in the tire radial direction.
7. A pneumatic tire according to claim 6,
the 3D sipe is deeper in the tire radial direction at the center portion than at both side portions in the tire width direction.
8. A pneumatic tire according to claim 6 or 7,
the sipes are formed more than the shoulder ribs in the center rib and the intermediate rib.
9. A pneumatic tire according to claim 6 or 7,
the pitch of the sipes formed in the center rib in the tire circumferential direction is 5% to 40% of the length of the center rib in the tire width direction.
10. A pneumatic tire according to claim 6 or 7,
the pitch of the sipes formed in the shoulder rib in the tire circumferential direction is 30% to 60% of the length of the shoulder rib in the tire width direction.
Technical Field
The present invention relates to a pneumatic tire.
Background
Patent document 1 discloses a pneumatic tire in which a block pattern is formed by a main groove extending in a tire circumferential direction and a lateral groove extending in a tire width direction, a bridge connecting blocks adjacent to each other in the tire circumferential direction is formed between the blocks adjacent to each other in the tire circumferential direction in order to suppress chipping (separation of a tread) of the blocks, and a sipe is formed in the bridge in order to suppress generation of uneven wear that may be increased by this.
Disclosure of Invention
Technical problem to be solved
In order to suppress uneven wear of the tread portion, it is also conceivable to form the tread portion in a rib pattern to increase the rigidity of the land portion and suppress deformation of the land portion. However, in this case, the traction element is reduced as compared with the block pattern, and therefore, the traction performance is easily lowered.
The present invention addresses the problem of improving traction while suppressing the occurrence of uneven wear in a pneumatic tire having a rib pattern.
(II) technical scheme
The present invention provides a pneumatic tire, wherein a plurality of ribs extending in a tire circumferential direction are formed in a tread portion by a plurality of main grooves extending in the tire circumferential direction, wherein a central rib which is divided into a central portion in the tire width direction among the plurality of ribs is formed with a plurality of closed grooves which extend in the tire width direction from one end portion communicating with the main grooves and end in the central rib at the other end portion, and the plurality of closed grooves are formed so as to face each other from both sides in the tire width direction of the central rib.
According to the present invention, in a pneumatic tire having a tread portion configured as a rib pattern, a pair of closed grooves facing each other in the tire width direction are formed in a center rib. Since the rigidity of the land portion (rib) is easily ensured by configuring the tread portion with a rib pattern, the wear resistance, uneven wear resistance, and low fuel consumption are improved as compared with a block pattern.
Further, the use of the closed groove suppresses a decrease in rigidity of the center rib, and easily functions as a traction component extending in the tire width direction. Further, since the closed groove is formed in a pair of the center ribs having a high ground contact pressure among the plurality of ribs along the tire width direction, the traction component generated by the pair of closed grooves is likely to act on the road surface substantially simultaneously at the time of ground contact, and thus, the traction performance is likely to be further improved.
Therefore, in the pneumatic tire having the rib pattern, the occurrence of uneven wear can be suppressed by suppressing the reduction in the rigidity of the rib, and the traction performance can be improved by the pair of closed grooves facing each other in the tire width direction.
Preferably, of the plurality of ribs, a shoulder rib that is defined at an outer end in the tire width direction is formed alternately in the tire circumferential direction with: a closed groove extending in the tire width direction from one end portion communicating with the main groove, and the other end portion ending in the shoulder rib; and a closed groove extending in the tire width direction from one end portion communicating with a ground contact end on the outer side in the tire width direction, and the other end portion ending in the shoulder rib.
Further, it is preferable that, among the plurality of ribs, an intermediate rib divided between the center rib and the shoulder rib in the tire width direction is alternately formed in the tire circumferential direction with: a closed groove extending in the tire width direction from one end portion communicating with the main groove on the center rib side, and the other end portion ending in the intermediate rib; and a closed groove extending in the tire width direction from one end portion communicating with the main groove on the shoulder rib side, and the other end portion ending in the intermediate rib.
Since the shoulder ribs and the intermediate ribs have a lower ground contact pressure than the center rib, uneven wear is more likely to occur due to sliding of the ground contact surface during ground contact than the center rib. Therefore, according to this configuration, the closed grooves are formed not so as to face each other in the tire width direction but so as to alternate in the tire circumferential direction from the outer side and the inner side in the tire width direction in the shoulder ribs and the intermediate ribs, which are more likely to cause uneven wear than the center rib. As a result, the closed groove can improve traction, and the rigidity of the shoulder rib and the intermediate rib can be easily made uniform in the tire circumferential direction, thereby suppressing uneven wear.
Further, it is preferable that the plurality of main grooves extend in a zigzag shape in the tire circumferential direction, and the closed groove communicating with the main grooves is formed in a corner portion of the plurality of ribs that is divided into concave shapes in the tire width direction by the main groove.
According to this configuration, the closed groove is formed in the corner portion of the plurality of ribs divided into the concave shape. That is, since the rib is formed so as to have an angle of 180 degrees or more at the corner portion in a plan view, the corner portion formed in a slit shape by the closed groove is less likely to have an acute angle by forming the closed groove at the corner portion. Therefore, the rigidity of the rib can be prevented from being lowered by the closed groove.
In the tire width direction, it is preferable that the center rib has a pair of closed grooves formed by a pair of the closed grooves facing each other in the tire width direction, and a coupling groove that couples the pair of closed grooves arranged in parallel in the tire width direction to each other in the tire width direction so as to face every other closed groove in the tire circumferential direction and is shallower than the closed groove.
According to this configuration, the edge component of the center rib extending in the tire width direction can be increased by the connecting groove, and therefore the traction performance can be further improved. Further, the coupling grooves are shallower than the closed grooves, and are formed so that every other pair of the plurality of closed grooves arranged in parallel in the tire circumferential direction is oriented in the tire circumferential direction, so that traction at the initial stage of wear is ensured, and a decrease in rigidity of the center rib due to the coupling grooves is suppressed.
In addition, it is preferable that a plurality of sipes extending in the tire width direction are formed in each of the plurality of ribs, and at least the sipe longest in the tire width direction among the plurality of sipes is a 3D sipe whose shape varies in the tire radial direction in each rib.
According to this structure, the traction is improved by the sipes formed in the plurality of ribs, respectively. At this time, the amount of deformation of the portion of the rib where the sipe longest in the tire width direction is formed is likely to increase, but by forming the sipe as a 3D sipe, it is possible to suppress excessive deformation, and thereby suppress the generation of uneven wear.
In addition, by forming at least the sipe that is longest in the tire width direction among the plurality of sipes as a 3D sipe, mold release properties at the time of tire vulcanization molding are easily ensured as compared with when all sipes are formed as 3D sipes.
In addition, it is preferable that the 3D sipe is deeper in the tire radial direction in the center portion than in both side portions in the tire width direction.
According to this configuration, by making both side portions of the 3D sipe shallower, excessive deformation of the portion where the 3D sipe is formed can be suppressed.
In addition, it is preferable that the sipe is formed more in the center rib and the intermediate rib than in the shoulder rib.
According to this configuration, the traction force is easily and effectively exerted by the closed grooves formed as a pair in the tire width direction and the sipes formed relatively in a large number in the center rib having a high ground contact pressure. On the other hand, in the shoulder rib having a low ground contact pressure, the closed grooves are not formed in a pair in the tire width direction, and the number of sipes is suppressed, so that the rigidity of the shoulder rib is suppressed from being lowered, and thereby the generation of uneven wear in the shoulder rib is suppressed.
Further, in the intermediate rib, a pair of closed grooves is not formed in the tire width direction, and a relatively large number of sipes are used, whereby a reduction in rigidity of the intermediate rib is suppressed, and traction performance is easily exhibited.
Thus, the traction can be effectively improved at the center rib where the ground contact pressure tends to be relatively high, and the generation of the partial wear can be suppressed at the shoulder rib where the ground contact pressure tends to be relatively low, and the traction can be improved and the partial wear can be suppressed in balance at the intermediate rib where the ground contact pressure is likely to be in between.
In addition, it is preferable that a forming pitch in the tire circumferential direction of the plurality of sipes formed in the center rib is 5% or more and 40% or less of a tire width direction length of the center rib.
According to this configuration, traction by the sipe is ensured in the center rib having a high ground contact pressure, and excessive deformation of the center rib is suppressed. If the sipe formation pitch is less than 5% of the width of the center rib, defects and cracks in the center rib are likely to occur. If the pitch of the central rib sipes is greater than 40% of the width of the central rib, the number of sipes becomes small, and the improvement amount of traction tends to be insufficient.
Further, it is preferable that a formation pitch in the tire circumferential direction of the plurality of sipes formed in the shoulder rib is 30% or more and 60% or less of a length of the shoulder rib in the tire width direction.
According to this structure, the number of sipes formed in the shoulder rib having a low ground contact pressure is reduced, and therefore excessive deformation of the shoulder rib can be suppressed. If the sipe formation pitch of the shoulder rib is less than 30% of the width of the shoulder rib, the rigidity of the shoulder rib is liable to be excessively lowered and to cause partial wear. If the sipe formation pitch of the shoulder rib is larger than 60% of the width of the shoulder rib, the number of sipes becomes small, and the improvement amount of the traction is liable to be insufficient.
(III) advantageous effects
According to the present invention, in the pneumatic tire having a rib pattern, the occurrence of uneven wear can be suppressed, and the traction performance can be improved.
Drawings
Fig. 1 is a semi-sectional view in the radial direction of a pneumatic tire according to an embodiment of the present invention.
Fig. 2 is a partially developed view of the tread portion of fig. 1.
Fig. 3 is a perspective view of the center rib as viewed from the arrow a of fig. 2.
Fig. 4 is a perspective view of the intervening rib as viewed from the B arrow of fig. 2.
Fig. 5 is a perspective view of the shoulder rib as viewed from the arrow C of fig. 2.
FIG. 6 is a cross-sectional view of the 3D sipe of section VI-VI of FIG. 2.
Description of the reference numerals
1-a pneumatic tire; 2-a tread portion; 10-a main tank; 11-14: first to fourth main grooves; 20-ribs; 21-a central rib; 22-intervening ribs; 23-shoulder ribs; 30-a closed tank; 31 to 36-first to sixth closed grooves; 37-closed slot pair; 38-a connecting groove; 39-shallow grooves; 40-central sipes; 50-an intervening sipe; 60-shoulder sipes.
Detailed Description
The following describes embodiments of the present invention 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. The drawings are schematic, and the ratio of the dimensions and the like are different from those in reality.
Fig. 1 is a cross-sectional view in the meridian direction of a pneumatic tire 1 according to an embodiment of the present invention, and shows one side (the right side in fig. 1) of a tire equator line CL. As shown in fig. 1, the pneumatic tire 1 includes: a
Fig. 2 is a partially developed view of the
Further, a plurality of ribs 20 are defined by the plurality of main grooves 10 in the
In the
That is, the
Fig. 3 is a perspective view of the
(center rib)
As shown in fig. 2, the
A first closed groove 31 is formed in a corner portion 21b of the
The first and second closed grooves 31, 32 are formed in a pair in the tire width direction with the tire equator line CL therebetween, and the pair of closed grooves 31, 32 constitutes a pair of
In the pair of
Further, the
Referring also to fig. 3, the plurality of first closed grooves 31 are formed such that first closed
Similarly, the second closed grooves 32 include a second closed
In the pair of
The depth H3 of the connecting
Further, a plurality of center sipes 40 penetrating in the tire width direction are formed in the
As shown in fig. 2, the
The
As shown in fig. 2, the forming pitch P1 in the tire circumferential direction of the center sipe 40 is set to be 5% or more and 40% or less of the tire width direction length W1 of the
(intermediate Rib)
The
A third
The third and
As shown in fig. 2, a plurality of intermediate sipes 50 penetrating in the tire width direction are formed in the
The first
The second and third
As shown in fig. 2, the formation pitch P2 in the tire circumferential direction of the intermediate sipe 50 is set to be 5% or more and 40% or less of the tire width direction length W2 of the
In addition, the number of the intermediate sipes 50 is set to be substantially the same as the number of the center sipes 40.
(shoulder Rib)
The side wall portion of the
A fifth
The
Further, the fifth
Further, a sixth
As shown in fig. 5, the groove depth H5 of the fifth and sixth
As shown in fig. 2, a plurality of shoulder sipes 60 penetrating in the tire width direction are formed in the
The
The
As shown in fig. 2, the formation pitch P3 in the tire circumferential direction of the shoulder sipe 60 is set to 30% to 60% of the length W3 of the
The number of shoulder sipes 60 is smaller than the number of center sipes 40 and the number of intermediate sipes 50, and specifically, 40% to 60% of the number of center sipes 40 and intermediate sipes 50.
The first to fifth closed grooves 31 to 35 are formed in the corner portions 21b, 22b, and 23b of the first to fourth
FIG. 6 is a cross-sectional view along the line VI-VI of FIG. 2 along the first
According to the pneumatic tire 1 described above, the following effects can be obtained.
(1) In the pneumatic tire 1 in which the
Further, the first and second closed grooves 31 and 32 suppress a decrease in rigidity of the
Therefore, in the pneumatic tire 1 configured as the rib pattern, the occurrence of uneven wear can be suppressed by suppressing the reduction in the rib rigidity, and the traction performance can be improved by the pair of opposing first and second closed grooves 31, 32.
(2) Since the
(3) First to fifth closed grooves 31 to 35 (hereinafter, collectively referred to as closed grooves 30) are formed in the recessed corners 21b, 22b, 23b (hereinafter, collectively referred to as 20b) of the plurality of ribs 20. That is, since the rib 20 is formed to have an angle of 180 degrees or more at the corner portion 20b in a plan view, the corner portion formed in a slit shape by the closed groove 30 is hardly made to have an acute angle by forming the closed groove 30 at the corner portion 20 b. Therefore, the rigidity of the rib can be suppressed from being lowered by the closed groove 30.
In particular, in the present embodiment, in the top view shown in fig. 2, each rib 20 has the closing groove 30 formed therein: the angle of the corner formed between the side wall portions of each rib 20 divided on both sides in the tire width direction is about 90 degrees or more. Therefore, the reduction in rigidity of the corner portion formed in the slit shape by the closed groove 30 can be suppressed, and the reduction in rigidity of the rib can be further suppressed.
(4) Since the edge component of the
Similarly, since the edge component of the
(5) Traction is improved by the sipes 40, 50, 60 formed in each of the plurality of ribs 20. At this time, the deformation amount of the portion of the rib 20 where the sipe longest in the tire width direction is formed, that is, the portion where the
Further, since the
(6) By making both side portions of the
(7) In the
In the
Thus, the traction can be effectively improved at the
(8) Since the formation pitch P1 of the center sipe 40 is set to be 5% or more and 40% or less of the tire width direction length W1 of the
(9) The shoulder sipe 60 has a formation pitch P3 set to 30% to 60% of the tire width direction length W3 of the
(10) The pair of
Although four main grooves 10 are formed in the above embodiment, the present invention is not limited to this, and two or more main grooves may be used. Further, in the case where the main groove 10 is two, the center rib may be divided therebetween, and the shoulder ribs may be divided on both sides in the tire width direction.
In the above embodiment, the case where each main groove 10 extends in a zigzag shape in the tire circumferential direction has been described as an example, but the present invention is not limited to this. Therefore, each main groove 10 may linearly extend in the tire circumferential direction.
The present invention is not limited to the configuration described in the above embodiment, and various modifications are possible.
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