JP5888368B2 - Pneumatic tire - Google Patents

Description

The present invention relates to a pneumatic tire in which a tread portion is provided with a center rib located on the tire equator and a plurality of block rows located on both sides thereof, and more particularly, to improve snow performance and quietness in a balanced manner. It relates to a pneumatic tire that has been made possible .

  In a pneumatic tire, a tread portion is provided with a plurality of circumferential grooves extending in the tire circumferential direction and a plurality of lug grooves extending in the tire width direction, and these circumferential grooves and the lug grooves are provided on the tire equator. A tread pattern in which a center rib located and a plurality of block rows located on both sides of the center rib are defined and a plurality of sipes are provided on each land portion has been proposed (for example, see Patent Documents 1 to 3).

  A pneumatic tire provided with such a tread pattern can exhibit good performance on snow based on circumferential grooves, lug grooves and sipes formed in the tread portion. Here, it is necessary to sufficiently secure the groove component of the tread portion in order to exhibit good performance on snow. However, when the groove component in the tread portion is increased, the air column resonance generated in the groove increases the noise outside the vehicle, so that the quietness of the pneumatic tire is deteriorated.

  Moreover, the effect of increasing the traction on snow is expected by forming the circumferential grooves in a zigzag shape along the tire circumferential direction. However, when the circumferential groove is formed in a zigzag shape, it becomes difficult to discharge snow clogged in the circumferential groove when traveling on snow. For this reason, even if zigzag circumferential grooves are used, the performance on snow cannot always be improved due to a decrease in snow removal performance.

JP 2009-120055 A JP 2010-167930 A JP 2010-188778 A

An object of the present invention is to provide a pneumatic tire that can improve the performance on snow and the quietness in a well-balanced manner.

In order to achieve the above object, a pneumatic tire according to the present invention includes a tread portion that extends in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and the sidewall portions. In a pneumatic tire provided with a pair of bead portions arranged on the inner side in the tire radial direction of
A pair of first circumferential main grooves extending zigzag along the tire circumferential direction on both sides of the tire equator in the tread portion, and along the tire circumferential direction on the outer side in the tire width direction of each first circumferential main groove A pair of second circumferential main grooves extending in a zigzag manner, and a pair of zigzag extending along the tire circumferential direction between the first circumferential main groove and the second circumferential main groove. A circumferential auxiliary groove and a plurality of first lug grooves extending from the first circumferential main groove to the ground contact end toward the outer side in the tire width direction are provided, and between the pair of first circumferential main grooves. A center rib is partitioned into a first block row composed of a plurality of first blocks between the first circumferential main groove and the circumferential auxiliary groove, and the circumferential auxiliary groove and the second circumferential direction are partitioned. A second block row composed of a plurality of second blocks is defined between the main groove and the second circumferential main groove. A shoulder block row composed of a plurality of shoulder blocks is defined on the outer side in the ear width direction, and a plurality of sipes extending in the tire width direction are provided on each of the center rib, the first block, the second block, and the shoulder block. the first block and the second block is disposed at a position shifted in the tire circumferential direction, is provided a cutout portion that is opened in the first circumferential-direction main groove in the center rib, it is formed on the center rib A notch portion is provided at the apex position protruding inward in the tire width direction of the first circumferential main groove, and a notch portion that opens in the circumferential auxiliary groove is provided in each of the second blocks. The notch part formed in 2 blocks is arrange | positioned in the position of the vertex which protruded the tire width direction outer side of the said circumferential direction auxiliary groove .

In the present invention, the first circumferential main groove, the second circumferential main groove, and the circumferential auxiliary groove are formed in a zigzag shape so that the first circumferential main groove, the second circumferential main groove, and the circumferential auxiliary groove are formed. Therefore, the snow column shear force in the tire circumferential direction can be increased, and the traction on the snow can be increased. Moreover, since each of the center rib and the second block is provided with a notched portion which is open to the first circumferential-direction main grooves or the circumferential auxiliary groove, of the first circumferential-direction main grooves or the circumferential auxiliary groove snow-expelling Sufficient performance can be secured and the effect of improving performance on snow can be fully enjoyed. In addition, since the first block and the second block are disposed at positions shifted from each other in the tire circumferential direction, air column resonance generated in the groove on the tire equator side is released to the outside in the tire width direction. It can be suppressed and noise outside the vehicle can be reduced. As a result, according to the present invention, it is possible to improve on-snow performance and quietness with a good balance.

  In the present invention, the tread portion is provided with a plurality of second lug grooves extending from the circumferential auxiliary groove toward the ground contact end toward the outer side in the tire width direction, and the first lug groove and the second lug groove are arranged in the tire circumferential direction. It is preferable that the first blocks are provided with notches that are alternately arranged and open in the first circumferential main groove or the circumferential auxiliary groove. By mixing the first lug groove extending from the first circumferential main groove toward the outer side in the tire width direction and the second lug groove extending from the circumferential auxiliary groove toward the outer side in the tire width direction in this way. Compared to the case where all the lug grooves extend to the vicinity of the tire equator, the noise outside the vehicle can be reduced. In this case, snow removal performance can be sufficiently ensured by providing each of the first blocks with a notch opening in the first circumferential main groove or the circumferential auxiliary groove.

  The shift amount G between the first block and the second block is preferably 50% to 150% of the groove width W of the first lug groove. As a result, the noise outside the vehicle can be reduced while maintaining good snow drainage performance.

  The amplitude A1 in the tire width direction of the virtual center line of the circumferential auxiliary groove is preferably 20% to 50% of the total width B of the first block row and the second block row. Thereby, the performance on snow can be improved without deteriorating the wear performance.

  The apex of the virtual center line of the circumferential auxiliary groove is arranged based on the relatively short pitch P1 and the relatively long pitch P2 alternately provided along the tire circumferential direction, and the ratio P1 of the pitch P1 to the pitch P2 / P2 is preferably 0.1 to 0.5. Thereby, the traction on snow can be increased without impairing snow removal performance.

  The amplitude A2 in the tire width direction of the virtual center line of the first circumferential main groove is 5% to 20% of the total width B of the first block row and the second block row, and the virtual width of the second circumferential main groove is The amplitude A3 of the center line in the tire width direction is preferably 5% to 20% of the total width B of the first block row and the second block row. Thereby, on-snow performance can be improved without deteriorating the drainage performance based on the first circumferential main groove and the second circumferential main groove.

  The apex of the imaginary center line of the first circumferential main groove is arranged based on the relatively short pitch P3 and the relatively long pitch P4 alternately provided along the tire circumferential direction, and the pitch P3 of the pitch P4 The ratio P3 / P4 is 0.1 to 0.5, and the apex of the virtual center line of the second circumferential main groove is relatively long with the relatively short pitch P5 alternately provided along the tire circumferential direction. It is preferable that the ratio P5 / P6 of the pitch P5 with respect to the pitch P6 is 0.1 to 0.5. Thereby, the traction on snow can be increased without impairing snow removal performance.

  The notch portion formed in the second block is preferably arranged at the position of the apex protruding outward in the tire width direction of the circumferential auxiliary groove, and the notch portion formed in the first block is the first circumferential main groove. It is preferable to arrange at the position of the apex protruding outward in the tire width direction of the tire, and the notch formed in the center rib is disposed at the position of the apex protruding inward in the tire width direction of the first circumferential main groove. preferable. Thereby, the improvement effect of the snow removal performance based on a notch part can be exhibited to the maximum extent.

  It is preferable that the depth of the notch gradually decreases from the open end toward the closed end. The cutout portion mainly contributes to the improvement of snow removal performance, but if the depth of the cutout portion is constant, the wear performance may be deteriorated.

  Further, the maximum depth D of the notch is preferably 10% to 90% of the groove depth FD of the groove adjacent to the notch. As a result, snow removal performance and drainage performance can be improved without adversely affecting the wear performance.

  The notch portion forms a pair of contour lines on the tread surface, and the pair of contour lines has a relatively small inclination with respect to the tire width direction and a second contour line with a relatively large inclination with respect to the tire width direction. The inclination angle θ1 of the first contour line with respect to the tire width direction is preferably 15 ° to 60 °. Thereby, snow removal performance and drainage performance can be improved.

  Moreover, it is preferable that a notch part forms a pair of outline on a tread, and opening angle (theta) 2 of this pair of outline is 15 degrees-30 degrees. Thereby, it is possible to improve the snow drainage performance and drainage performance without adversely affecting the wear performance.

In the present invention, the snow traction index STI represented by the following formula (1) is preferably 180 or more in order to sufficiently ensure the performance on snow.
STI = −6.8 + 2202ρg + 672ρs + 7.6Dg (1)
However, ρg: groove density (mm / mm ² ) = gross length of the extended component in the tire width direction of the groove (mm)
/ Total area of ground contact area (mm ² )
ρs: sipe density (mm / mm ² ) = total length of extension components in sipe tire width direction (mm) / total area of contact area (mm ² )
Dg: Average groove depth (mm)

  In the present invention, the contact area of the tread portion is the contact width in the tire axial direction measured when a normal load is applied by placing the tire on a regular rim and filling the regular internal pressure vertically on a plane. Specified based on. The ground contact edge is the outermost position in the tire axial direction of the ground contact region. The “regular rim” is a rim determined for each tire in the standard system including the standard on which the tire is based, for example, a standard rim for JATMA, “Design Rim” for TRA, or ETRTO. Then, “Measuring Rim” is set. “Regular internal pressure” is the air pressure that each standard defines for each tire in the standard system including the standard on which the tire is based. The maximum air pressure is JATMA, and the table “TIRE ROAD LIMITS AT VARIOUS” is TRA. The maximum value described in “COLD INFRATION PRESURES”, “INFLATION PRESURE” for ETRTO, but 180 kPa when the tire is a passenger car. “Regular load” is a load determined by each standard for each tire in the standard system including the standard on which the tire is based. The maximum load capacity is JATMA, and the table “TIRE ROAD LIMITS AT VARIOUS” is TRA. The maximum value described in “COLD INFORATION PRESSURES” is “LOAD CAPACITY” if it is ETRTO, but if the tire is a passenger car, the load is equivalent to 88% of the load.

It is meridian sectional drawing which shows the pneumatic tire which consists of embodiment of this invention. FIG. 2 is a development view showing a tread pattern of the pneumatic tire of FIG. 1. It is a top view which shows a 1st block row | line | column and a 2nd block row | line | column with a dimension line. It is a top view which shows a 1st block row | line | column and a 2nd block row | line with another dimension line. It is a top view which shows a center rib, a 1st block row | line | column, a 2nd block row | line | column, and a shoulder block row | line | column with a dimension line. It is sectional drawing which shows a notch part with a dimension line. It is a top view which shows a center rib, a 1st block row | line | column, and a 2nd block row | line | column with a dimension line. It is an expanded view which shows the tread pattern of the pneumatic tire which consists of other embodiment of this invention.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. 1 to 7 show a pneumatic tire according to an embodiment of the present invention.

  As shown in FIG. 1, the pneumatic tire of the present embodiment includes a tread portion 1 that extends in the tire circumferential direction and has an annular shape, and a pair of sidewall portions 2, 2 disposed on both sides of the tread portion 1. And a pair of bead portions 3 and 3 disposed inside the sidewall portion 2 in the tire radial direction.

  A carcass layer 4 is mounted between the pair of bead portions 3 and 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire radial direction, and is folded from the inside of the tire to the outside around the bead core 5 disposed in each bead portion 3. A bead filler 6 made of a rubber composition having a triangular cross-section is disposed on the outer periphery of the bead core 5.

  On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 7 include a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and are arranged so that the reinforcing cords cross each other between the layers. In the belt layer 7, the inclination angle of the reinforcing cord with respect to the tire circumferential direction is set in a range of, for example, 10 ° to 40 °. A steel cord is preferably used as the reinforcing cord of the belt layer 7. For the purpose of improving high-speed durability, at least one belt cover layer 8 in which reinforcing cords are arranged at an angle of, for example, 5 ° or less with respect to the tire circumferential direction is disposed on the outer peripheral side of the belt layer 7. Yes. As the reinforcing cord of the belt cover layer 8, an organic fiber cord such as nylon or aramid is preferably used.

  In addition, although the tire internal structure mentioned above shows the typical example in a pneumatic tire, it is not limited to this.

  As shown in FIG. 2, the tread portion 1 includes a pair of first circumferential main grooves 11 extending zigzag along the tire circumferential direction on both sides of the tire equator CL, and each first circumferential main groove 11. Between the pair of second circumferential main grooves 12 extending in the zigzag shape along the tire circumferential direction, and between the first circumferential main grooves 11 and the second circumferential main grooves 12. A pair of circumferential auxiliary grooves 13 extending in a zigzag shape along the direction, and a plurality of first lug grooves 21 extending from the first circumferential main groove 11 toward at least the ground contact edge E toward the outer side in the tire width direction. In addition, a plurality of second lug grooves 22 extending from the circumferential auxiliary groove 13 toward at least the ground contact edge E toward the outer side in the tire width direction are formed. The first lug grooves 21 and the second lug grooves 22 are alternately arranged along the tire circumferential direction. Further, this pneumatic tire is a tire in which the rotation direction R is specified, but the first lug groove 21 and the second lug groove 22 are opposite to the rotation direction R from the tire equator CL side toward the outer side in the tire width direction. Inclined to. The first circumferential main groove 11 and the second circumferential main groove 12 are grooves having a groove width in the range of 7 mm to 10 mm and a groove depth in the range of 8.0 mm to 12.0 mm. On the other hand, the circumferential auxiliary groove 13 is narrower than the first circumferential main groove 11 and the second circumferential main groove 12, has a groove width in the range of 3 mm to 5 mm, and has a groove depth of 7.0 mm to 11. It is a groove in the range of 0 mm.

  Thus, in the tread portion 1, the center rib 30 is defined between the pair of first circumferential main grooves 11, 11, and a plurality of gaps are provided between the first circumferential main groove 11 and the circumferential auxiliary groove 13. A first block row 40 composed of the first blocks 41 is partitioned, and a second block row 50 composed of a plurality of second blocks 51 is partitioned between the circumferential auxiliary groove 13 and the second circumferential main groove 12. A shoulder block row 60 composed of a plurality of shoulder blocks 61 is defined on the outer side in the tire width direction of the second circumferential main groove 12. Each of the center rib 30, the first block 41 of the first block row 40, the second block 51 of the second block row 50, and the shoulder block 61 of the shoulder block row 60 has a plurality of pieces extending in the tire width direction. Sipes 32, 42, 52, and 62 are formed. These sipes 32, 42, 52, 62 may extend linearly or may extend in a zigzag manner.

  In the pneumatic tire, the center axis position of the first lug groove 21 is shifted in the middle, and as a result, the first block 41 and the second block 51 are disposed at positions shifted from each other in the tire circumferential direction.

  Further, each of the center rib 30, the first block 41, and the second block 51 has a notch 33 that opens into the first circumferential main groove 11, the second circumferential main groove 12, or the circumferential auxiliary groove 13, respectively. 43 and 53 are formed.

  In the pneumatic tire described above, the first circumferential main groove 11, the second circumferential main groove 12, and the circumferential auxiliary groove 13 are formed in a zigzag shape, so that the first circumferential main groove 11 and the second circumferential direction are formed. The snow column shear force in the tire circumferential direction based on the main groove 12 and the circumferential auxiliary groove 13 can be increased, and the traction on the snow can be increased. Thus, when the first circumferential main groove 11, the second circumferential main groove 12 and the circumferential auxiliary groove 13 are formed in a zigzag shape, there is a possibility that the snow clogged in the groove is difficult to be discharged when running on snow, Each of the center rib 30, the first block 41, and the second block 51 has notches 33, 43, 53 that open to the first circumferential main groove 11, the second circumferential main groove 12, or the circumferential auxiliary groove 13. Since it is provided, the snow removal performance of the first circumferential main groove 11, the second circumferential main groove 12 or the circumferential auxiliary groove 13 can be sufficiently ensured, and the effect of improving the performance on snow can be fully enjoyed. .

  In addition, since the first block 41 and the second block 51 are arranged at positions shifted from each other in the tire circumferential direction, air column resonance generated in the groove on the tire equator CL side is emitted outward in the tire width direction. Can be suppressed, and noise outside the vehicle can be reduced. As a result, it is possible to improve on-snow performance and quietness in a well-balanced manner. In particular, as shown in FIG. 2, the first lug groove 21 extending from the first circumferential main groove 11 toward the outer side in the tire width direction and the first lug groove 21 extending from the circumferential auxiliary groove 13 toward the outer side in the tire width direction. When the two lug grooves 22 are alternately arranged along the tire circumferential direction, noise outside the vehicle can be effectively reduced.

  As shown in FIG. 3, the shift amount G between the first block 31 and the second block 41 is preferably 50% to 150% of the groove width W of the first lug groove 21. As a result, the noise outside the vehicle can be reduced while maintaining good snow drainage performance. If the shift amount G is smaller than 50% of the groove width W, the effect of reducing outside noise is reduced, and conversely if it is larger than 150% of the groove width W, the snow drainage performance is lowered.

  As shown in FIG. 4, the amplitude A1 in the tire width direction of the virtual center line (illustrated by a broken line) of the circumferential auxiliary groove 13 is 20% to 50% of the total width B of the first block row 40 and the second block row 50. % Is good. Thereby, the performance on snow can be improved without deteriorating the wear performance. When the amplitude A1 is smaller than 20% of the total width B, the effect of improving the performance on snow is lowered. On the contrary, when the amplitude A1 is larger than 50% of the total width B, the rigidity of the first block 41 and the second block 51 is decreased and wear is reduced. Adversely affects performance. The total width B of the first block row 40 and the second block row 50 is a portion that protrudes most toward the tire equator CL side of the first block row 40 and a portion that protrudes most outward in the tire width direction of the second block row 50. It is the distance of the tire width direction between.

  As shown in FIG. 4, the vertices of the virtual center line of the circumferential auxiliary groove 13 have relatively short pitches P1 and relatively long pitches P2 (P1 <P2) given alternately along the tire circumferential direction. The ratio P1 / P2 of the pitch P1 with respect to the pitch P2 is preferably 0.1 to 0.5. By setting the ratio P1 / P2 within the above range and sufficiently securing the circumferential component of the circumferential auxiliary groove 13, the traction on the snow can be increased without impairing the snow removal performance. If the ratio P1 / P2 is smaller than 0.1, the effect of increasing the traction on snow is reduced. Conversely, if the ratio P1 / P2 is larger than 0.5, the circumferential component of the circumferential auxiliary groove 13 is reduced, so that the snow discharging performance is improved. descend.

  As shown in FIG. 5, the amplitude A2 in the tire width direction of the virtual center line (illustrated by a broken line) of the first circumferential main groove 11 is 5% of the total width B of the first block row 40 and the second block row 50. The amplitude A3 in the tire width direction of the virtual center line (illustrated by a broken line) of the second circumferential main groove 12 is 5% of the total width B of the first block row 40 and the second block row 50 It is good to be 20%. Thereby, on-snow performance can be improved without deteriorating the drainage performance based on the first circumferential main groove 11 and the second circumferential main groove 12. When the amplitudes A2 and A3 are smaller than 5% of the total width B, the effect of improving the performance on snow is lowered.

  As shown in FIG. 5, the vertices of the imaginary center line of the first circumferential main groove 11 have relatively short pitches P3 and relatively long pitches P4 (P3 <P4) alternately provided along the tire circumferential direction. The ratio P3 / P4 of the pitch P3 to the pitch P4 is preferably 0.1 to 0.5. Further, the vertices of the virtual center line of the second circumferential main groove 12 are arranged based on relatively short pitches P5 and relatively long pitches P6 (P5 <P6) given alternately along the tire circumferential direction. The ratio P5 / P6 of the pitch P5 to the pitch P6 is preferably 0.1 to 0.5. By setting the ratio P3 / P4 and the ratio P5 / P6 within the above ranges and sufficiently securing the circumferential components of the first circumferential main groove 11 and the second circumferential main groove 12, the snow discharge performance is not impaired. Traction on the snow can be increased. If the ratio P3 / P4 or the ratio P5 / P6 is smaller than 0.1, the effect of increasing the traction on the snow is reduced, and conversely if it is larger than 0.5, the first circumferential main groove 11 or the second circumferential direction. Since the circumferential component of the main groove 12 is reduced, the snow removal performance is lowered.

  As shown in FIG. 4, the notch 53 formed in the second block 51 is preferably arranged at the position of the apex protruding outward in the tire width direction of the circumferential auxiliary groove 13. Further, as shown in FIG. 5, the notch 43 formed in the first block 41 is arranged at the position of the apex protruding outward in the tire width direction of the first circumferential main groove 11 and formed in the center rib 30. The notch 33 is preferably disposed at the position of the apex protruding inward in the tire width direction of the first circumferential main groove 11. Thus, by arranging the notches 33, 43, 53 at the apex positions of the first circumferential main groove 11 and the circumferential auxiliary groove 13, the effect of improving snow removal performance based on the notches 33, 43, 53 is achieved. Can be maximized.

  As shown in FIG. 6, the depth of the notches 33, 43, 53 is preferably gradually reduced from the open end toward the closed end. The notches 33, 43, 53 mainly contribute to the improvement of snow removal performance, but if the depth of the notches 33, 43, 53 is constant, the wear performance may be deteriorated. . Even if the notches 33, 43, 53 are shallow at the closed end portion in order to maintain good wear performance, if the notches 33, 43, 53 are deepened at the open end portion, the adjacent notches The snow removal performance of the 1st circumferential direction main groove 11, the 2nd circumferential direction main groove 12, or the circumferential direction auxiliary groove 13 can be improved.

  Further, the maximum depth D of the notches 33, 43, 53 is the same as that of the first circumferential main groove 11, the second circumferential main groove 12, or the circumferential auxiliary groove 13 adjacent to the notches 33, 43, 53. It is preferable to be 10% to 90% of the groove depth FD. As a result, snow removal performance and drainage performance can be improved without adversely affecting the wear performance. If the maximum depth D of the notches 33, 43, 53 is less than 10% of the groove depth FD, the effect of improving the snow drainage performance and drainage performance is reduced, and conversely if greater than 90%, the center rib 30, The rigidity of the first block 41 or the second block 51 is lowered, and the wear performance is adversely affected. In particular, regarding the cutout portion 43 formed in the first block 41 and the cutout portion 53 formed in the second block 51, the maximum depth D may be 10% to 50% of the groove depth FD. preferable. On the other hand, for the notch 33 formed in the center rib 30 having relatively high rigidity, the maximum depth D is preferably set to 70% to 90% of the groove depth FD.

  As shown in FIG. 7, the notches 33, 43, 53 form a pair of contour lines L1, L2 on the tread surface. That is, the wall surfaces on both sides of the notches 33, 43, 53 intersect with the tread portion 1 to form a pair of contour lines L 1, L 2. Here, the pair of contour lines L1, L2 are a first contour line L1 having a relatively small inclination with respect to the tire width direction (a direction orthogonal to the tire equator CL) and a second contour line having a relatively large inclination with respect to the tire width direction. The inclination angle θ1 of the first contour line L1 with respect to the tire width direction is preferably 15 ° to 60 °. Thus, snow drainage performance and drainage performance can be improved by appropriately inclining the first contour line L1 of the notches 33, 43, 53 with respect to the tire width direction. When the inclination angle θ1 of the first contour line L1 is out of the above range, the effect of improving snow drainage performance and drainage performance is reduced.

  In addition, the opening angle θ2 of the pair of contour lines L1 and L2 in the notches 33, 43, and 53 is preferably 15 ° to 30 °. Thus, by making the notches 33, 43, 53 into a shape that is appropriately opened, it is possible to improve the snow drainage performance and drainage performance without adversely affecting the wear performance. If the opening angle θ2 of the contour lines L1 and L2 is smaller than 15 °, the effect of improving the snow drainage performance and the drainage performance is deteriorated.

  FIG. 8 shows a tread pattern of a pneumatic tire according to another embodiment of the present invention. 8, the same components as those in FIGS. 1 to 7 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 8, instead of the second lug groove 22 in FIG. 2, a first lug groove 21 extending from the first circumferential main groove 11 toward at least the ground contact end E toward the outer side in the tire width direction is arranged. . In this case, since the first block row 40 is subdivided by the first lug groove 21, the notch 43 is not formed in the first block 41.

  Even in the pneumatic tire described above, the first circumferential main groove 11, the second circumferential main groove 12, the second circumferential main groove 12, and the circumferential auxiliary groove 13 are formed in a zigzag shape. The snow column shear force in the tire circumferential direction based on the directional main groove 12 and the circumferential auxiliary groove 13 can be increased, and the traction on the snow can be increased. Moreover, since the center rib 30 and the second block 51 are each provided with notches 33 and 53 that open to the first circumferential main groove 11, the second circumferential main groove 12, or the circumferential auxiliary groove 13, The snow removal performance of the first circumferential main groove 11, the second circumferential main groove 12 or the circumferential auxiliary groove 13 can be sufficiently secured, and the effect of improving the performance on snow can be fully enjoyed. In addition, since the first block 41 and the second block 51 are arranged at positions shifted from each other in the tire circumferential direction, air column resonance generated in the groove on the tire equator CL side is emitted outward in the tire width direction. Can be suppressed, and noise outside the vehicle can be reduced. As a result, it is possible to improve on-snow performance and quietness in a well-balanced manner.

  In a pneumatic tire having a tread portion, a pair of sidewall portions, and a pair of bead portions with a tire size 225 / 65R17 102Q, the tread portion extends zigzag along the tire circumferential direction on both sides of the tire equator. A pair of first circumferential main grooves, a pair of second circumferential main grooves extending zigzag along the tire circumferential direction on the outer side in the tire width direction of each first circumferential main groove, and the first circumferential direction A pair of circumferential auxiliary grooves extending in a zigzag shape along the tire circumferential direction between the main groove and the second circumferential main groove, and from the first circumferential main groove toward the outer side in the tire width direction to the ground contact end A plurality of first lug grooves extending from each other and a plurality of second lug grooves extending from the circumferential auxiliary groove toward the ground contact end toward the outer side in the tire width direction are provided. A center rib is defined between the first circumferential main groove and the circumference. A first block row consisting of a plurality of first blocks is defined between the auxiliary grooves and a second block row consisting of a plurality of second blocks is defined between the circumferential auxiliary grooves and the second circumferential main groove. , A shoulder block row composed of a plurality of shoulder blocks is defined outside the second circumferential main groove in the tire width direction, and a plurality of center ribs, a first block, a second block, and a shoulder block extend in the tire width direction. Examples 1 to 23 in which a sipe is provided, the first block and the second block are arranged at positions shifted from each other in the tire circumferential direction, and a notch portion is provided in each of the center rib, the first block, and the second block. Tires were made.

  In Examples 1 to 23, the displacement G between the first block and the second block (ratio to the groove width W of the first lug groove), the inclination angle θ1 of the notch, the opening angle θ2 of the notch, the notch Maximum depth D (ratio to groove depth FD), circumferential auxiliary groove amplitude A1 (ratio to total width B of first block row and second block row), circumferential auxiliary groove pitch ratio P1 / P2 Was set as shown in Table 1 and Table 2. Further, the amplitude A2 of the first circumferential main groove and the amplitude A3 of the second circumferential main groove are 10%, respectively, and the pitch ratio P3 / P4 of the first circumferential main groove and the pitch ratio P5 of the second circumferential main groove. / P6 was set to 0.3 respectively.

  For comparison, the shift amount G between the first block and the second block is set to 0%, the first circumferential main groove, the second circumferential main groove, and the circumferential auxiliary groove are formed linearly, and the center rib, Conventional tires having the same structure as in Example 1 were prepared except that notches were not provided in the first block and the second block.

  These test tires were evaluated for quietness, braking performance on snow, and wear performance by the following test methods, and the results are also shown in Tables 1 and 2. Each evaluation was performed under the condition that the test tire was mounted on a wheel with a rim size of 17 × 7 J and mounted on a front-wheel drive vehicle with a displacement of 2000 cc, and the air pressure after warm-up was 220 kPa.

Silence:
About each test tire, the passage noise outside a vehicle was measured based on European noise regulation conditions (ECE R117). The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the better the quietness.

Snow braking performance:
For each test tire, the braking distance from the running state on the snow under the same conditions until the brake was applied was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. The larger the index value, the better the braking performance on snow.

Wear performance:
Each test tire was subjected to a road test under the same conditions, and the amount of wear in the tread portion was measured. The evaluation results are shown as an index with the conventional example being 100, using the reciprocal of the measured value. A larger index value means better wear performance.

  As can be seen from Table 1 and Table 2, the tires of Examples 1 to 23 were excellent in both on-snow braking performance and quietness in comparison with the conventional example.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 11 1st circumferential direction main groove 12 2nd circumferential direction main groove 13 Circumferential direction auxiliary groove 21 1st lug groove 22 2nd lug groove 30 Center rib 32, 42, 52 Sipe 33, 43, 53 Notch 40 First block row 41 First block 50 Second block row 51 Second block 60 Shoulder block row 61 Shoulder block

Claims (12)

An annular tread portion extending in the tire circumferential direction, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the inner side in the tire radial direction of the sidewall portions. In the provided pneumatic tire,
A pair of first circumferential main grooves extending zigzag along the tire circumferential direction on both sides of the tire equator in the tread portion, and along the tire circumferential direction on the outer side in the tire width direction of each first circumferential main groove A pair of second circumferential main grooves extending in a zigzag manner, and a pair of zigzag extending along the tire circumferential direction between the first circumferential main groove and the second circumferential main groove. A circumferential auxiliary groove and a plurality of first lug grooves extending from the first circumferential main groove to the ground contact end toward the outer side in the tire width direction are provided, and between the pair of first circumferential main grooves. A center rib is partitioned into a first block row composed of a plurality of first blocks between the first circumferential main groove and the circumferential auxiliary groove, and the circumferential auxiliary groove and the second circumferential direction are partitioned. A second block row composed of a plurality of second blocks is defined between the main groove and the second circumferential main groove. A shoulder block row composed of a plurality of shoulder blocks is defined on the outer side in the ear width direction, and a plurality of sipes extending in the tire width direction are provided on each of the center rib, the first block, the second block, and the shoulder block. the first block and the second block is disposed at a position shifted in the tire circumferential direction, is provided a cutout portion that is opened in the first circumferential-direction main groove in the center rib, it is formed on the center rib A notch portion is provided at the apex position protruding inward in the tire width direction of the first circumferential main groove, and a notch portion that opens in the circumferential auxiliary groove is provided in each of the second blocks. a pneumatic tire, wherein the notches formed in the two blocks to the arrangement of the position of the vertex protruding in the tire width direction outer side of the circumferential auxiliary groove   The tread portion is provided with a plurality of second lug grooves extending from the circumferential auxiliary groove toward the ground contact end toward the outer side in the tire width direction, and the first lug groove and the second lug groove are arranged in the tire circumferential direction. 2. The pneumatic tire according to claim 1, wherein the pneumatic tire according to claim 1, wherein the pneumatic tires are alternately arranged, and each of the first blocks is provided with a notch that opens in the first circumferential main groove or the circumferential auxiliary groove.   3. The pneumatic tire according to claim 1, wherein a shift amount G between the first block and the second block is 50% to 150% of a groove width W of the first lug groove.   The amplitude A1 in the tire width direction of the virtual center line of the circumferential auxiliary groove is 20% to 50% of the total width B of the first block row and the second block row. The pneumatic tire according to any one of the above.   The apex of the virtual center line of the circumferential auxiliary groove is arranged based on a relatively short pitch P1 and a relatively long pitch P2 alternately provided along the tire circumferential direction, and the pitch P1 with respect to the pitch P2 The pneumatic tire according to claim 1, wherein a ratio P1 / P2 of the tire is 0.1 to 0.5.   The amplitude A2 in the tire width direction of the virtual center line of the first circumferential main groove is 5% to 20% of the total width B of the first block row and the second block row, and the second circumferential main groove The amplitude A3 of the imaginary center line in the tire width direction is 5% to 20% of the total width B of the first block row and the second block row. Pneumatic tires.   The apex of the imaginary center line of the first circumferential main groove is arranged based on a relatively short pitch P3 and a relatively long pitch P4 alternately provided along the tire circumferential direction, and the pitch with respect to the pitch P4 The ratio P3 / P4 of the pitch P3 is 0.1 to 0.5, and the relatively short pitch P5 alternately provided along the tire circumferential direction with the vertices of the virtual center line of the second circumferential main groove It arrange | positions based on relatively long pitch P6, and ratio P5 / P6 of the said pitch P5 with respect to the said pitch P6 is 0.1-0.5, The one in any one of Claims 1-6 characterized by the above-mentioned. Pneumatic tires. The air according to any one of claims 2 to 7 , wherein the cutout portion formed in the first block is disposed at a position of a vertex protruding outward in the tire width direction of the first circumferential main groove. Enter tire. The pneumatic tire according to any one of claims 1 to 8 , wherein a depth of the notch portion is gradually reduced from an open end toward a closed end. The pneumatic tire according to any one of claims 1 to 9 , wherein a maximum depth D of the notch is 10% to 90% of a groove depth FD of a groove adjacent to the notch. . The notch portion forms a pair of contour lines on the tread surface, and the pair of contour lines has a first contour line having a relatively small inclination with respect to the tire width direction and a second contour having a relatively large inclination with respect to the tire width direction. and a line, the pneumatic tire according to any one of claims 1 to 10, the inclination angle θ1 is characterized in that it is a 15 ° to 60 ° with respect to the tire width direction of the first contour line. The air according to any one of claims 1 to 11 , wherein the notch portion forms a pair of contour lines on a tread surface, and an opening angle θ2 of the pair of contour lines is 15 ° to 30 °. Enter tire.

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