JP2021104754A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire capable of improving traction performance on an ice/snow road while ensuring draining performance.SOLUTION: A tire PT is equipped with a center block row 10 in which a plurality of center blocks 1 are aligned at a center portion in a tire width direction of a tread surface Tr, and a pair of shoulder block rows 20 and 30 in which a plurality of shoulder blocks 2 and 3 are aligned at both end portions in a tire width direction of the tread surface Tr, and a pair of quarter block rows 40 and 50 in which a plurality of quarter blocks are aligned between the center block row 10 and the pair of shoulder block rows 20 and 30. A plurality of quarter blocks 5 and the plurality of shoulder blocks 3 are arranged in parallel on a vehicle installation outer side of a single center block 1. In a vehicle installation outer area Ao, a quarter lateral groove 51 is provided on an extension of a groove axis of a center lateral groove 11, and a shoulder lateral groove 31 is provided on an extension of a groove axis of the quarter lateral groove 51.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to pneumatic tires.

Pneumatic tires for winter are required to have traction performance on icy and snowy roads. In addition, it is important to ensure drainage performance.

In the pneumatic tire described in Patent Document 1, a single center block extends in the tire circumferential direction across three or more second blocks. As a result, the groove area in the central portion of the tread surface in the tire width direction is reduced, and the braking performance and turning performance on the ice road surface (ice road surface) are improved. However, with regard to the center block, except for the length in the tire circumferential direction, it is beyond the range of the prior art.

Japanese Unexamined Patent Publication No. 2006-232151

An object of the present disclosure is to provide a pneumatic tire capable of improving traction performance on icy and snowy roads while ensuring drainage performance.

The pneumatic tire of the present disclosure has a designated mounting direction with respect to the vehicle, and includes a center block row in which a plurality of center blocks are arranged in the tire circumferential direction via a center lateral groove at the center of the tread surface in the tire width direction, and the above. A plurality of shoulder block rows in which a plurality of shoulder blocks are arranged in the tire circumferential direction via shoulder lateral grooves at both ends in the tire width direction of the tread surface, and a plurality of shoulder block rows between the center block row and the pair of shoulder block rows. A pair of quarter block rows in which the quarter blocks are arranged in the tire circumferential direction via a quarter lateral groove are provided, and a plurality of the quarter blocks and a plurality of the shoulder blocks are arranged side by side on the vehicle mounting outer side of the single center block. In the vehicle mounting outer region of the tread surface, the quarter lateral groove is provided on the extension of the groove center line of the center lateral groove, and the shoulder lateral groove is provided on the extension of the groove center line of the quarter lateral groove. ing.

Top view showing an example of the tread surface of the pneumatic tire of the present disclosure. Top view showing the main part of the vehicle mounting outer region Top view showing the main part of the vehicle mounting inner region

Hereinafter, one embodiment of the present disclosure will be described with reference to the drawings.

FIG. 1 is a plan view of a tread surface Tr included in the pneumatic tire PT of the present embodiment (hereinafter, also simply referred to as “tire PT”). The vertical direction in FIG. 1 corresponds to the tire circumferential direction, and the horizontal direction in FIG. 1 corresponds to the tire width direction. As shown in FIG. 1, the tread pattern formed on the tread surface Tr is a block pattern.

The pneumatic tire PT of the present embodiment is a mounting direction designation type tire in which the mounting direction with respect to the vehicle is designated. The arrow OUT points to the outside of the vehicle, and the arrow IN points to the inside of the vehicle. The region on the right side of FIG. 1 with respect to the tire equator TE is the vehicle-mounted outer region Ao of the tread surface Tr, and the region on the left side of FIG. 1 is the vehicle-mounted inner region Ai of the tread surface Tr. When the tire PT is mounted on the vehicle, the vehicle mounting outer region Ao is directed to the outside of the vehicle, and the vehicle mounting inner region Ai is directed to the inside of the vehicle. The mounting direction is specified, for example, by attaching a display such as "OUTSIDE" or "INSIDE" to the outer surface of the sidewall portion of the tire PT.

The pneumatic tire PT includes a center block row 10 in which a plurality of center blocks 1 are arranged in the tire circumferential direction via a center lateral groove 11 at the center of the tread surface Tr in the tire width direction, and both ends of the tread surface Tr in the tire width direction. Between the pair of shoulder block rows 20 and 30 in which a plurality of shoulder blocks 2 and 3 are arranged in the tire circumferential direction via the shoulder lateral grooves 21 and 31, and the center block row 10 and the pair of shoulder block rows 20 and 30. A plurality of quarter blocks 4 and 5 are provided with a pair of quarter block rows 40 and 50 arranged in the tire circumferential direction via quarter lateral grooves 41 and 51. The center block row 10 is provided on the tire equator TE.

The five block rows 10, 20, 30, 40, 50 are partitioned by four circumferential grooves 61 to 64 that extend continuously in the tire circumferential direction. The circumferential groove for partitioning the block row is a main groove or a groove having a depth of 50% or more of the main groove. In the present embodiment, the three circumferential grooves 61 to 63 are the main grooves. The circumferential groove 64 is not a main groove, but has a depth of 50% or more of the depth of the main groove (for example, the circumferential groove 62). The circumferential groove 64 is formed shallower than the main groove, and has a depth of 50 to 85% of the depth of the main groove in the present embodiment. The center block row 10 is divided into a circumferential groove 62 and a circumferential groove 64 located across the tire equator TE.

In the present embodiment, the width W64 of the circumferential groove 64 that separates the center block row 10 and the quarter block row 50 of the vehicle mounting outer region Ao determines the center block row 10 and the quarter block row 40 of the vehicle mounting inner region Ai. It is smaller than the width W62 of the circumferential groove 62 for partitioning. The width W64 is, for example, 3.0 mm or less, and more specifically, it is set to 1.2 to 1.8 mm. The width W64 is, for example, 0.9% or more of the ground contact width CW. The width W62 is, for example, 3% or more of the ground contact width CW. The width W61 and the width W63 of the circumferential groove 63 are, for example, 4% or more of the ground contact width CW.

The ground contact width CW is the width of the ground contact surface when the tire PT is rim-assembled on the regular rim, the tire PT is placed vertically on a flat road surface with the regular internal pressure charged, and a regular load is applied. The ground contact end CE is the outermost position of the ground contact surface in the tire width direction. Therefore, the distance in the tire width direction between the pair of ground contact ends CE is the ground contact width CW. The dimensions of the grooves, blocks, sipes, etc. described above are measured with the tire mounted on the regular rim filled with the regular internal pressure and with no load.

A regular rim is a rim defined for each tire in the standard system including the standard on which the tire is based. For example, JATMA is a standard rim, and TRA and ETRTO are "Measuring Rim". The regular internal pressure is the air pressure defined for each tire in the standard system including the standard on which the tire is based. For JATMA, the maximum air pressure, and for TRA, the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". If it is the maximum value described in "ETRTO", it is "INFLATION PRESSURE". If the tire is for a passenger car, the value is 180 kPa, and if the tire is described as Extra Load or Reinforced, the value is 220 kPa. The normal load is the load defined for each tire in the standard system including the standard on which the tire is based. For JATMA, the maximum load capacity, for TRA, the maximum value listed in the above table. If it is ETRTO, it is "LOAD CAPACITY", but if the tires are for passenger cars, it is 88% of the corresponding load of the internal pressure.

The center block 1 has a shape that is longer in the tire circumferential direction than in the tire width direction. The pair of shoulder blocks 2 and 3 and the pair of quarter blocks 4 and 5 each have a shape longer in the tire circumferential direction than in the tire width direction. The center block 1, the pair of shoulder blocks 2 and 3, and the pair of quarter blocks 4 and 5 each form a quadrangle (quadrilateral) in a plan view, but the present invention is not limited to this, and various shapes can be adopted.

A plurality of sipes 12 are formed in the center block 1. The sipe 12 is formed by a notch having a width of 1.0 mm or less. In order to improve the traction performance on the ice road surface, the inclination angle θ12 (see FIG. 2) of the sipe 12 with respect to the tire width direction is preferably 45 degrees or less, more preferably 30 degrees or less. The sipe 12 is formed as a corrugated sipe, but the sipe 12 is not limited to this, and may be a straight sipe, for example. Although both ends of the sipe 12 are closed, one end or both ends may be opened in the circumferential grooves 62, 64 or the center lateral groove 11. The sipe 12 may be a two-dimensional sipe whose shape does not change along the depth direction, or a three-dimensional sipe including a portion whose shape changes along the depth direction.

Sipes 22 and 32 are formed on the pair of shoulder blocks 2 and 3, respectively. Sipes 42 and 52 are formed in the pair of quarter blocks 4 and 5, respectively. In the present embodiment, the sipe 12 arranged in the central portion in the tire width direction and the sipe 32 and 52 arranged in the vehicle mounting outer region Ao are compared with the sipe 22 and 42 arranged in the vehicle mounting inner region Ai. , Formed by corrugated sipes with small wavelengths. As a result, the edge effect in the tire width direction is enhanced in the vehicle mounting outer region Ao where the contribution during turning is large, and the edge effect in the tire circumferential direction is enhanced in the vehicle mounting inner region Ai where the contribution during driving and braking is large.

As shown enlarged in FIG. 2, a plurality of (three in the present embodiment) quarter blocks 5 and a plurality of (two in the present embodiment) shoulder blocks 3 are mounted on the outside of the single center block 1 mounted on the vehicle. And are installed side by side. Therefore, the center block 1 extends longer in the tire circumferential direction than the shoulder block 3 and the quarter block 5. The arrangement pitch (interval in the tire circumferential direction) P31 of the shoulder lateral grooves 31 is, for example, 35 to 55% of the arrangement pitch P11 of the center lateral grooves 11. The arrangement pitch P51 of the quarter lateral groove 51 is, for example, 25 to 35% of the arrangement pitch P11 of the center lateral groove 11.

In the vehicle mounting outer region Ao, a quarter lateral groove 51 is provided on the extension of the groove center line CL1 of the center lateral groove 11 instead of the side surface of the quarter block 5. Further, a shoulder lateral groove 31 is provided on the extension of the groove center line CL5 of the quarter lateral groove 51 (quarter lateral groove 51 provided on the extension of the groove center line CL1 of the center lateral groove 11) instead of the side surface of the shoulder block 3. ing. As a result, the center lateral groove 11, the quarter lateral groove 51, and the shoulder lateral groove 31 are connected to each other on the same line, and the drainage effect to the outside of the vehicle is enhanced. In the present embodiment, since the circumferential groove 64 is a narrower and shallower groove than the main groove such as the circumferential groove 62, such a structure is particularly useful.

On an icy road surface having a low friction coefficient, the contact pressure at the center of the tread surface Tr in the tire width direction tends to be relatively high, which contributes to traction performance. Since the center block 1 provided at the center in the tire width direction extends long in the tire circumferential direction, the length and number of sipe 12 can be increased, and the edge component of the sipe 12 can be increased. Further, if the center block 1 collapses significantly at the time of initial movement, it is difficult to properly exert the edge effect of the sipe 12, but since the center block 1 is long in the tire circumferential direction, the rigidity of the center block 1 is increased and excessive at the time of initial movement is achieved. It can suppress the collapse.

As described above, while increasing the edge component of the sipe 12, it is possible to suppress an excessive collapse of the center block 1 at the time of initial movement, so that the traction performance on the ice road surface is improved. Further, since the lengths of the shoulder block 3 and the quarter block 5 in the tire circumferential direction are relatively small, the number of shoulder lateral grooves 31 and quarter lateral grooves 51 can be secured, and the traction performance on a snowy road surface can be improved. In addition, since the center lateral groove 11, the quarter lateral groove 51, and the shoulder lateral groove 31 are connected to each other on the same line, drainage performance is ensured.

The quarter lateral groove 51 includes a relatively wide quarter lateral groove 51a and a relatively narrow quarter lateral groove 51b, and one wide quarter lateral groove 51a and two narrow quarter lateral grooves 51b form a tire circumference. They are arranged alternately in the direction. A wide quarter lateral groove 51a is provided on the extension of the groove center line CL1 of the center lateral groove 11. The shoulder lateral groove 31 includes a relatively wide shoulder lateral groove 31a and a relatively narrow shoulder lateral groove 31b, which are arranged alternately in the tire circumferential direction. A wide shoulder lateral groove 31a is provided on the extension of the groove center line CL5 of the wide quarter lateral groove 51a.

As shown enlarged in FIG. 3, in the vehicle mounting inner region Ai, the shoulder lateral groove 21 is not on the side surface of the shoulder block 2 but on the extension of the groove center line CL4 of the quarter lateral groove 41 (the wide quarter lateral groove 41a described later). Is provided. As a result, the quarter lateral groove 41 and the shoulder lateral groove 21 are connected to each other on the same line, and the drainage effect to the inside of the vehicle mounting is enhanced. The quarter lateral groove 41 includes a relatively wide quarter lateral groove 41a and a relatively narrow quarter lateral groove 41b, which are arranged alternately in the tire circumferential direction.

In the vehicle mounting inner region Ai, the side surface of the quarter block 4 is provided on the extension of the groove center line CL1 of the center lateral groove 11. Therefore, the center lateral groove 11 and the quarter lateral groove 41 are not connected to each other on the same line. Therefore, between the center block row 10 and the quarter block row 40, the block edge in contact with the lateral groove is displaced in the tire circumferential direction. According to such a configuration, the effect of suppressing the generation of pattern noise can be obtained.

The center block 1 extends longer in the tire circumferential direction than the shoulder block 2 and the quarter block 4. The arrangement pitch P21 of the shoulder lateral groove 21 is, for example, 35 to 55% of the arrangement pitch P11 (see FIG. 2) of the center lateral groove 11. The arrangement pitch P41 of the quarter lateral groove 41 is, for example, 25 to 35% of the arrangement pitch P11 of the center lateral groove 11.

The widths W2 and W3 of the shoulder blocks 2 and 3 are larger than the width W1 of the center block 1, respectively. As a result, the area of the shoulder blocks 2 and 3 which are smaller in the tire circumferential direction than the center block 1 does not become too small, which is effective in ensuring the turning performance. The width W1 is set to, for example, 7 to 17% of the ground contact width CW. The widths W2 and W3 are set to, for example, 15 to 25% of the ground contact width CW. Since the widths W4 and W5 of the pair of quarter blocks 4 and 5 are also larger than the width W1, the same effect can be obtained. The width W4 is set to, for example, 13 to 23% of the ground contact width CW. The width W5 is set to, for example, 14 to 24% of the ground contact width CW.

The pneumatic tire PT is useful as a winter tire or an all-season tire because it is characterized by the structure of the tread surface Tr as described above and has excellent traction performance on icy and snowy roads. In the case of a winter tire, the rubber hardness of the tread rubber forming the tread surface Tr is, for example, 45 to 65 °. This rubber hardness is the hardness measured at 23 ° C. according to the durometer hardness test (type A) of JIS K6253.

As described above, in the pneumatic tire PT of the present embodiment, the mounting direction with respect to the vehicle is specified, and a plurality of center blocks 1 are located in the central portion of the tread surface Tr in the tire width direction in the tire circumferential direction via the center lateral groove 11. A pair of shoulder block rows 20 in which a plurality of shoulder blocks 2 and 3 are arranged in the tire circumferential direction via shoulder lateral grooves 21 and 31 at both ends of the tread surface Tr in the tire width direction. A pair of quarter block rows 40, in which a plurality of quarter blocks 4 and 5 are arranged in the tire circumferential direction via quarter lateral grooves 41 and 51 between the 30 and the center block row 10 and the pair of shoulder block rows 20 and 30. A plurality of quarter blocks 5 and a plurality of shoulder blocks 3 are arranged side by side on the vehicle mounting outer side of a single center block 1, and in the vehicle mounting outer region of the tread surface Tr, a center lateral groove 11 is provided. A quarter lateral groove 51 is provided on the extension of the groove center line CL1, and a shoulder lateral groove 31 is provided on the extension of the groove center line CL5 of the quarter lateral groove 51.

In this tire PT, the edge component of the sipe 12 can be increased in the center block 1, and excessive collapse at the time of initial movement can be suppressed, so that the traction performance on the ice road surface is improved. Further, since the number of shoulder lateral grooves 31 and quarter lateral grooves 51 is secured, the traction performance on the snowy road surface is improved. Moreover, since the center lateral groove 11, the quarter lateral groove 51, and the shoulder lateral groove 31 are connected to each other on the same line, drainage performance is ensured.

In the pneumatic tire PT of the present embodiment, the width W64 of the circumferential groove 64 that separates the center block row 10 and the quarter block row 50 in the vehicle mounting outer region is the quarter block row of the center block row 10 and the vehicle mounting inner region. It is smaller than the width W62 of the circumferential groove 62 that partitions the 40. As a result, the rigidity of the region where the center block 1 and the plurality of (three in the present embodiment) quarter blocks 5 are provided can be increased, and the traction performance on the ice road surface can be effectively improved.

In the pneumatic tire PT of the present embodiment, the shoulder lateral groove 21 is provided on the extension of the groove center line CL4 of the quarter lateral groove 41 in the vehicle mounting inner region of the tread surface Tr. Since the quarter lateral groove 41 and the shoulder lateral groove 21 are connected to each other on the same line, the drainage effect to the inside of the vehicle is enhanced.

In the pneumatic tire PT of the present embodiment, the side surface of the quarter block 4 is provided on the extension of the groove center line CL1 of the center lateral groove 11 in the vehicle mounting inner region of the tread surface Tr. As a result, between the center block row 10 and the quarter block row 40, the block edge in contact with the lateral groove is displaced in the tire circumferential direction, and the effect of suppressing the generation of pattern noise can be obtained.

In the pneumatic tire PT of the present embodiment, the arrangement pitch P51 of the quarter lateral grooves 51 in the vehicle mounting outer region of the tread surface Tr is 25 to 35% of the arrangement pitch P11 of the center lateral grooves 11. As a result, the number of quarter lateral grooves 51 can be secured, and the traction performance on the snowy road surface can be improved.

The pneumatic tire PT can be configured in the same manner as a normal pneumatic tire except that the tread surface Tr is configured as described above, and any conventionally known material, shape, structure, manufacturing method, etc. can be adopted. Although not shown, the pneumatic tire PT is provided on a pair of bead portions, a pair of sidewall portions extending outward in the tire radial direction from each of the bead portions, and the tire radial outer ends of the pair of sidewall portions. It is provided with a continuous tread portion, and the outer peripheral surface of the tread portion is formed by a tread surface Tr.

Although the embodiments of the present disclosure have been described with reference to the drawings, it should be considered that the specific configuration is not limited to this embodiment. The scope of the present disclosure is shown not only by the description of the above-described embodiment but also by the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

The pneumatic tire of the present disclosure is not limited to the above-described embodiment, and is not limited to the above-mentioned action and effect. The pneumatic tire of the present disclosure can be improved and changed in various ways without departing from the gist thereof.

1 ... Center block, 2 ... Shoulder block, 3 ... Shoulder block, 4 ... Quarter block, 5 ... Quarter block, 10 ... Center block row, 11 ... Center horizontal groove, 12 ... Sipe, 20 ... Shoulder block row, 21 ... Shoulder lateral groove, 30 ... Shoulder block row, 31 ... Shoulder lateral groove, 40 ... Quarter block row, 41 ... Quarter lateral groove , 50 ... Quarter block row, 51 ... Quarter lateral groove, 61 ... Circumferential groove, 62 ... Circumferential groove, 63 ... Circumferential groove, 64 ... Circumferential groove, CL1 ...・ ・ Groove center line, CL4 ・ ・ ・ Groove center line, CL5 ・ ・ ・ Groove center line, TE ・ ・ ・ Tire equatorial line, Tr ・ ・ ・ Tread surface

Claims (5)

The mounting direction for the vehicle is specified,
A row of center blocks in which a plurality of center blocks are arranged in the tire circumferential direction via a center lateral groove at the center of the tread surface in the tire width direction, and
A pair of shoulder block rows in which a plurality of shoulder blocks are arranged in the tire circumferential direction via shoulder lateral grooves at both ends of the tread surface in the tire width direction.
A pair of quarter block rows in which a plurality of quarter blocks are arranged in the tire circumferential direction via a quarter lateral groove between the center block row and the pair of shoulder block rows are provided.
A plurality of the quarter blocks and a plurality of the shoulder blocks are arranged side by side on the outside of the single center block mounted on the vehicle.
In the vehicle mounting outer region of the tread surface, the quarter lateral groove is provided on the extension of the groove center line of the center lateral groove, and the shoulder lateral groove is provided on the extension of the groove center line of the quarter lateral groove. tire. The width of the circumferential groove that separates the center block row and the quarter block row in the vehicle mounting outer region is larger than the width of the circumferential groove that separates the center block row and the quarter block row in the vehicle mounting inner region. The small, pneumatic tire according to claim 1. The pneumatic tire according to claim 1 or 2, wherein the shoulder lateral groove is provided on an extension of the groove center line of the quarter lateral groove in the vehicle mounting inner region of the tread surface. The pneumatic tire according to any one of claims 1 to 3, wherein a side surface of the quarter block is provided on an extension of the groove center line of the center lateral groove in the vehicle mounting inner region of the tread surface. The pneumatic tire according to any one of claims 1 to 4, wherein the arrangement pitch of the quarter lateral grooves in the vehicle mounting outer region of the tread surface is 25 to 35% of the arrangement pitch of the center lateral grooves.

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