JP2020059461A - tire - Google Patents

Abstract

To provide a tire that can be improved in steering stability on a dry road surface and on-snow performance.SOLUTION: The tire has a tread part 2 in which a direction of mounting to a vehicle is specified. The tread part 2 has a first tread end Te1, a second tread end Te2, a plurality of main grooves 3 and a plurality of land parts 4. The main grooves 3 include first shoulder main grooves 5, second shoulder main grooves 6 and one crown main groove 7. The land parts 4 include first middle land parts 11, second middle land parts 12, first shoulder land parts 13 and second shoulder land parts 14. The first middle land part 11 is provided with a plurality of first middle lateral grooves 16. The second middle land part 12 is provided with a plurality of second middle lateral grooves 17. The first shoulder land part 13 is provided with a plurality of first shoulder lateral groove 18 completely crossing the land part. The second shoulder land part 14 is provided with a plurality of second shoulder lateral grooves 19 completely crossing the land part.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a tire, and more particularly, to a tire having a tread portion whose mounting direction in a vehicle is designated.

  BACKGROUND ART Conventionally, various tires having a tread portion in which a mounting direction on a vehicle is designated have been proposed (for example, refer to Patent Document 1 below).

JP, 2005-140047, A

  By the way, in tires that are supposed to run on both dry and snowy roads, the lateral grooves provided in the tread portion help improve the on-snow performance, but reduce the pattern rigidity of the tread portion, and There was a problem of deteriorating the driving stability on the road surface. As a result of various experiments, the inventors of the present invention have improved the above-mentioned problem by defining the arrangement of each lateral groove in a tire having a tread portion whose mounting direction in a vehicle is designated.

  The present invention has been devised in view of the above problems, and a main object of the present invention is to provide a tire capable of improving steering stability on a dry road surface and snow performance.

  The present invention is a tire having a tread portion whose direction of attachment to a vehicle is designated, wherein the tread portion is located at a first tread end located inside the vehicle when the vehicle is attached and outside the vehicle when the vehicle is attached. A second tread end, a plurality of main grooves extending continuously in the tire circumferential direction between the first tread end and the second tread end, and a plurality of land portions divided into the main grooves. The main groove is a first shoulder main groove arranged between the first tread end and the tire equator, and a second shoulder main groove arranged between the second tread end and the tire equator, It includes one crown main groove arranged between the first shoulder main groove and the second shoulder main groove, and the land portion is between the first shoulder main groove and the crown main groove. The divided first middle land portion and the second shoulder main groove A second middle land portion partitioned between the crown main groove, a first shoulder land portion partitioned between the first shoulder main groove and the first tread end, and a second shoulder main groove. And a second shoulder land portion that is divided between the second tread end and a plurality of second shoulder land portions that extend from the first shoulder main groove and are interrupted in the first middle land portion. A first middle lateral groove is provided, a plurality of second middle lateral grooves extending from the crown main groove and interrupted in the second middle land portion are provided at the second middle land portion, and the first shoulder land portion is provided. A plurality of first shoulder lateral grooves that completely traverse the first shoulder land portion are provided, and a plurality of second shoulder lateral grooves that completely traverse the second shoulder land portion are provided at the second shoulder land portion. There is.

  In the tire of the present invention, each of the first middle lateral groove and the second middle lateral groove is inclined in a first direction with respect to a tire axial direction, and each of the first shoulder lateral groove and the second shoulder lateral groove is a tire. It is desirable to incline in a second direction opposite to the first direction with respect to the axial direction.

  In the tire of the present invention, it is preferable that the second middle land portion is provided with a plurality of non-transverse middle sipes that extend from the crown main groove and are interrupted in the second middle land portion.

  In the tire of the present invention, the length of the non-crossing middle sipes in the tire axial direction is preferably 0.50 to 0.90 times the width of the second middle land portion in the tire axial direction.

  In the tire of the present invention, it is preferable that the first middle land portion is provided with a plurality of transverse middle sipes extending from the first shoulder main groove to the crown main groove.

  In the tire of the present invention, it is preferable that the first shoulder land portion is provided with a plurality of first shoulder sipes extending from the first shoulder main groove to an outer side in the tire axial direction.

  In the tire of the present invention, it is desirable that the second shoulder land portion is provided with a plurality of second shoulder sipes whose both ends are interrupted in the second shoulder land portion.

  In the tire of the present invention, the minimum distance from the second shoulder main groove to the second shoulder sipe is preferably 2 to 20 mm.

  In the tire of the present invention, the rigidity of the second middle land portion in the tire circumferential direction is preferably larger than the rigidity of the first middle land portion in the tire circumferential direction.

  In the tire of the present invention, the rigidity of the second shoulder land portion in the tire circumferential direction is preferably larger than the rigidity of the first shoulder land portion in the tire circumferential direction.

  The present invention is a tire having a tread portion in which a mounting direction in a vehicle is designated. The tread portion includes a first tread end located inside the vehicle when the vehicle is mounted, a second tread end located outside the vehicle when the vehicle is mounted, and a tire circumference between the first tread end and the second tread end. It has a plurality of main grooves extending continuously in the direction and a plurality of land portions divided into the main grooves.

  The main groove, a first shoulder main groove arranged between the first tread end and a tire equator, a second shoulder main groove arranged between the second tread end and a tire equator, and It includes one crown main groove arranged between the first shoulder main groove and the second shoulder main groove. The land portion includes a first middle land portion that is partitioned between the first shoulder main groove and the crown main groove, and a second middle land portion that is partitioned between the second shoulder main groove and the crown main groove. A middle land portion, a first shoulder land portion partitioned between the first shoulder main groove and the first tread end, and a second shoulder main groove partitioned between the second tread end. A second shoulder land portion is included.

  The first middle land portion is provided with a plurality of first middle lateral grooves that extend from the first shoulder main groove and are interrupted in the first middle land portion. The second middle land portion is provided with a plurality of second middle lateral grooves that extend from the crown main groove and are interrupted in the second middle land portion.

  The first middle lateral groove and the second middle lateral groove enhance snow performance by a reaction force when the snow is pressed and compressed in the groove when traveling on snow. Further, since the first middle lateral groove and the second middle lateral groove are discontinued in the land portion, the rigidity of the first tread edge side (vehicle outer side) of the first middle land portion and the second middle land portion decreases. To be prevented. Therefore, when turning on a dry road surface, when the center of the ground contact surface moves to the second tread end side, twist deformation of the first middle land portion and the second middle land portion is suppressed, and a large cornering power is generated. As a result, excellent steering stability is exhibited.

  The first shoulder land portion of the present invention is provided with a plurality of first shoulder lateral grooves that completely traverse the first shoulder land portion. The second shoulder land portion is provided with a plurality of second shoulder lateral grooves that completely cross the second shoulder land portion. Such a first shoulder lateral groove and a second shoulder lateral groove can generate laterally long snow columns when running on snow, and can further enhance traction on snow.

  As described above, the tire of the present invention can improve the steering stability on dry road surfaces and the snow performance.

It is a development view of the tread portion of the tire of one embodiment of the present invention. It is an enlarged view of the 1st middle land part and the 2nd middle land part of FIG. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG. It is an enlarged view of the 1st shoulder land part of FIG. It is the EE sectional view taken on the line of FIG. It is an enlarged view of the 2nd shoulder land part of FIG. It is a development view of a tread portion of a tire of a comparative example.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a development view of a tread portion 2 of a tire 1 showing an embodiment of the present invention. The tire 1 of the present embodiment is suitably used, for example, as a pneumatic tire for passenger cars. However, the present invention is not limited to such an aspect, and may be used for a heavy-duty pneumatic tire or a non-pneumatic tire in which pressurized air is not filled in the tire.

  As shown in FIG. 1, the tire 1 of the present invention has a tread portion 2 in which a mounting direction in a vehicle is designated. The tread portion 2 has a first tread end Te1 located outside the vehicle when the tire 1 is mounted on the vehicle, and a second tread end Te2 located inside the vehicle when mounted on the vehicle. The direction of mounting on the vehicle is displayed, for example, in characters or symbols on the sidewall portion (not shown).

  In the case of a pneumatic tire, the first tread end Te1 and the second tread end Te2 are the outermost ground contact positions in the axial direction of the tire 1 when a normal load is applied to the tire 1 in a normal state and the tire 1 comes in contact with a plane at a camber angle of 0 °. is there. The normal state is a state in which the tire is assembled on the regular rim, the regular internal pressure is filled, and no load is applied. In the present specification, unless otherwise specified, the dimensions and the like of each part of the tire are values measured in the normal state.

  The "regular rim" is a rim that is defined for each tire in the standard system including the standard on which the tire is based. For example, "standard rim" for JATMA, "Design Rim" for TRA, and ETRTO. If there is "Measuring Rim".

  "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. For JATMA, "maximum air pressure", and for TRA, the table "TIRE LOAD LIMITS AT The maximum value described in "VARIOUS COLD INFLATION PRESSURES" is "INFLATION PRESSURE" for ETRTO.

  "Regular load" is the load that each standard defines for each tire in the standard system including the standard on which the tire is based. For JATMA, "maximum load capacity", and for TRA, the table "TIRE LOAD LIMITS" The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES" is "LOAD CAPACITY" for ETRTO.

  The tread portion 2 has a plurality of main grooves 3 continuously extending in the tire circumferential direction between a first tread end Te1 and a second tread end Te2, and a plurality of land portions 4 divided into the main grooves 3. .

  The main groove 3 is a first shoulder main groove 5 arranged between the first tread end Te1 and the tire equator C, and a second shoulder main groove arranged between the second tread end Te2 and the tire equator C. 6 and one crown main groove 7 arranged between the first shoulder main groove 5 and the second shoulder main groove 6.

  The distance L1 in the tire axial direction from the tire equator C to the groove center line of the first shoulder main groove 5 or the second shoulder main groove 6 is preferably, for example, 0.15 to 0.30 times the tread width TW. . The tread width TW is a distance in the tire axial direction from the first tread end Te1 to the second tread end Te2 in the normal state.

  The crown main groove 7 is provided on the tire equator C, for example. However, it is not limited to such an aspect.

  Each main groove 3 of the present embodiment extends, for example, in a straight line in parallel with the tire circumferential direction. Each main groove 3 may be, for example, one that extends in a wave shape.

  The groove width Wa of each main groove 3 is preferably, for example, 3.0% to 6.0% of the tread width TW. In the case of a pneumatic tire for passenger cars, the depth of each main groove 3 is preferably, for example, 5 to 10 mm.

  The land portion 4 includes a first middle land portion 11, a second middle land portion 12, a first shoulder land portion 13, and a second shoulder land portion 14. The tread portion 2 of the present embodiment has a so-called 4-rib pattern composed of the above-mentioned three main grooves 3 and four land portions 4. The first middle land portion 11 is divided between the first shoulder main groove 5 and the crown main groove 7. The second middle land portion 12 is divided between the second shoulder main groove 6 and the crown main groove 7. The first shoulder land portion 13 is sectioned between the first shoulder main groove 5 and the first tread end Te1. The second shoulder land portion 14 is sectioned between the second shoulder main groove 6 and the second tread end Te2.

  FIG. 2 shows an enlarged view of the first middle land portion 11 and the second middle land portion 12. As shown in FIG. 2, the tire axial width W1 of the first middle land portion 11 and the tire axial width W2 of the second middle land portion 12 are, for example, 0.15 of the tread width TW. It is desirable to be 0.25 times. In the present embodiment, the width W1 and the width W2 are equal to each other. However, it is not limited to such an aspect.

  The first middle land portion 11 is provided with a plurality of first middle lateral grooves 16. The first middle lateral groove 16 extends from the first shoulder main groove 5 and is interrupted in the first middle land portion 11. Further, the second middle land portion 12 is provided with a plurality of second middle lateral grooves 17. The second middle lateral groove 17 extends from the crown main groove 7 and is interrupted in the second middle land portion 12.

  The first middle lateral groove 16 and the second middle lateral groove 17 enhance the on-snow performance by the reaction force when the snow is pressed and compacted in the groove and is sheared during traveling on the snow. In addition, since the first middle lateral groove 16 and the second middle lateral groove 17 are discontinued in the land portion, the rigidity of the first tread edge Te2 side (vehicle outer side) of the first middle land portion 11 and the second middle land portion 12 is reduced. The drop is prevented. Therefore, when turning on a dry road surface, when the center of the ground contact surface moves to the second tread end Te2 side, twist deformation of the first middle land portion 11 and the second middle land portion 12 is suppressed, and a large cornering power is obtained. Occurs, which in turn results in excellent steering stability.

  As shown in FIG. 1, the first shoulder land portion 13 is provided with a plurality of first shoulder lateral grooves 18 that completely traverse the first shoulder land portion 13. In addition, the second shoulder land portion 14 is provided with a plurality of second shoulder lateral grooves 19 that completely cross the second shoulder land portion 14. The first shoulder lateral groove 18 and the second shoulder lateral groove 19 as described above can generate a horizontally long snow column when traveling on snow, and can further enhance traction on snow.

  As a more desirable aspect, in the present embodiment, each of the first middle lateral groove 16 and the second middle lateral groove 17 is inclined in the first direction with respect to the tire axial direction. Each of the first shoulder lateral groove 18 and the second shoulder lateral groove 19 is inclined in a second direction opposite to the first direction with respect to the tire axial direction. As a result, the tread portion 2 can be prevented from being easily deformed in a specific direction, and steering stability can be further enhanced. Further, such middle lateral grooves and respective shoulder lateral grooves generate snow pillars having different inclination directions when traveling on snow and provide snow pillar shearing force in multiple directions, so that snow performance can also be improved.

  Each of the first middle lateral groove 16, the second middle lateral groove 17, the first shoulder lateral groove 18, and the second shoulder lateral groove 19 is preferably inclined at an angle of 45 ° or less with respect to the tire axial direction. Such a groove arrangement provides excellent traction when traveling on snow. More specifically, it is desirable that the first middle lateral groove 16 and the second middle lateral groove 17 be inclined, for example, at an angle of 10 to 20 with respect to the tire axial direction. The first shoulder lateral groove 18 and the second shoulder lateral groove 19 are preferably inclined at an angle of 5 to 15 ° with respect to the tire axial direction.

  As shown in FIG. 2, the first middle lateral groove 16 crosses the center of the first middle land portion 11 in the tire axial direction, for example. Specifically, the length L2 of the first middle lateral groove 16 in the tire axial direction is, for example, 0.70 to 0.90 times the width W1 of the first middle land portion 11 in the tire axial direction. Such a first middle lateral groove 16 enhances the steering stability on a dry road surface and the snow performance in a well-balanced manner.

  The first middle lateral groove 16 is, for example, a groove that is continuous with the narrow width portion 16a including the discontinuous end in the first middle land portion 11 and the first shoulder main groove 5 side of the narrow width portion 16a and is larger than the narrow width portion 16a. It includes a width widening portion 16b. The length of the narrow portion 16a in the tire axial direction is, for example, 0.50 times or more, and preferably 0.60 to 0.80 times, the length L2 of the first middle lateral groove 16 in the tire axial direction. Such a first middle lateral groove 16 can improve the performance on snow while maintaining the rigidity of the first middle land portion 11.

  FIG. 3 shows a sectional view of the first middle lateral groove 16 of FIG. 2 taken along the line AA. As shown in FIG. 3, the first middle lateral groove 16 preferably has, for example, a shallow bottom portion 16c with a raised bottom surface. The depth d2 of the shallow bottom portion 16c is, for example, 0.60 to 0.75 times the maximum depth d1 of the first middle lateral groove 16. Such a shallow bottom portion 16c can prevent the first middle lateral groove 16 from opening excessively while ensuring the groove volume.

  For easy understanding of the configuration of the shallow bottom portion 16c, the shallow bottom portion 16c is colored for one of the first middle lateral grooves 16 shown in FIG. As shown in FIG. 2, the shallow bottom portion 16c is provided in the widened portion 16b, for example. In a desirable mode, the shallow bottom portion 16c is provided at a distance from the end of the first middle lateral groove 16 on the first shoulder main groove 5 side. The width of the shallow bottom portion 16c in the tire axial direction is, for example, 0.10 to 0.30 times the length L2 of the first middle lateral groove 16 in the tire axial direction.

  In the first middle land portion 11, a plurality of transverse middle sipes 23 extending from the first shoulder main groove 5 to the crown main groove 7 and a plurality of first connecting sipes extending from the discontinuity of the first middle lateral groove 16 to the crown main groove 7. And 21 are provided. In addition, in this specification, "sipe" means a notch having a width of less than 1.5 mm. The width of the sipes is more preferably 0.5 to 1.0 mm, for example.

  The transverse middle sipes 23 are, for example, provided alternately with the first middle lateral grooves 16 in the tire circumferential direction. The transverse middle sipes 23 are inclined in the same direction as the first middle lateral grooves 16 with respect to the tire axial direction, for example. The angle of the transverse middle sipes 23 with respect to the tire axial direction is, for example, 10 to 20 °.

  FIG. 4 shows a cross-sectional view of the transverse middle sipe 23 of FIG. 2 taken along the line BB. As shown in FIG. 4, the transverse middle sipe 23 has, for example, a plurality of shallow bottom sipe portions 25 whose bottom surface is raised. The transverse middle sipe 23 of the present embodiment has, for example, a first shallow-bottom sipe portion 25a whose bottom surface is raised at the end portion on the first shoulder main groove 5 side and a second shallow bottom sipe portion 25a whose bottom surface is raised at the end portion on the crown main groove 7 side. It includes a shallow bottom sipe portion 25b and a third shallow bottom sipe portion 25c whose bottom surface is raised between the first shallow bottom sipe portion 25a and the second shallow bottom sipe portion 25b.

  In the present embodiment, the depth of the third shallow sipe portion 25c is larger than the depth of the first shallow sipe portion 25a and the depth of the second shallow sipe portion 25b. When the ground pressure acts on the transverse middle sipe 23 as described above, both end portions are more difficult to open than the central portion, and excessive deformation of the first middle land portion 11 is effectively suppressed.

  The maximum depth of the transverse middle sipes 23 is preferably 0.25 to 0.75 times the depth of the crown main groove 7, for example. Such a crossing middle sipe 23 can enhance the steering stability on dry road surfaces and the snow performance in a well-balanced manner.

  As shown in FIG. 2, the first connection sipe 21 inclines in the same direction as the first middle lateral groove 16, for example. The first connection sipe 21 of the present embodiment extends, for example, so as to be smoothly continuous with the edge of the first middle lateral groove 16.

  In the first middle land portion 11, a plurality of first middle portions which are connected to the first middle lateral groove 16 and in which a corner portion between the tread of the first middle land portion 11 and the side wall of the first shoulder main groove 5 side is recessed A chamfer 26 is provided. In a desirable mode, the first middle chamfered portion 26 is continuous with each first middle lateral groove 16. Further, the first middle chamfered portion 26 is connected to one side (the lower side in FIG. 2) of the first middle lateral groove 16 in the tire circumferential direction.

  The first middle chamfered portion 26 of the present embodiment is provided at the projected corner portion where the angle between the first shoulder main groove 5 and the first middle lateral groove 16 is an acute angle. In other words, the first middle lateral groove 16 is inclined toward one side in the tire circumferential direction from the first shoulder main groove 5 toward the crown main groove 7, and the first middle chamfered portion 26 is the first middle lateral groove 16. Is connected to one side in the tire circumferential direction.

  FIG. 5 shows a cross-sectional view of the first middle chamfered portion 26 taken along the line CC. As shown in FIG. 5, the first middle chamfered portion 26 includes a first surface 26 a extending along a side wall of the first middle land portion 11 and a second surface 26 b extending along a tread surface of the first middle land portion 11. Includes and.

  The maximum depth d4 of the first middle chamfered portion 26 is preferably, for example, 0.60 to 0.80 times the depth d3 of the first shoulder main groove 5. The first middle chamfered portion 26 of the present embodiment has, for example, the same depth as the first middle lateral groove 16. Such a first middle chamfered portion 26 is useful for enhancing the steering stability on dry road surfaces and the snow performance in a well-balanced manner.

  As shown in FIG. 2, from the same viewpoint, the width W3 of the first middle chamfered portion 26 in the tire axial direction is, for example, 0.05 to 0..0 of the width W1 of the first middle land portion 11 in the tire axial direction. It is preferably 15 times. The length of the first middle chamfered portion 26 in the tire circumferential direction is preferably, for example, 1.5 to 2.5 times the groove width of the continuous first middle lateral grooves 16.

  The first middle land portion 11 is not provided with a groove communicating with the crown main groove 7. In addition, the first middle land portion 11 is not provided with the above-mentioned chamfered portion on the crown main groove 7 side. Such a first middle land portion 11 has high rigidity on the side of the second tread end Te2, and can further improve steering stability.

  The length L3 of the second middle lateral groove 17 in the tire axial direction is preferably smaller than the length of the first middle lateral groove 16 in the tire axial direction, for example. Specifically, the length L3 of the second middle lateral groove 17 is, for example, 0.40 to 0.60 times the width W2 of the second middle land portion 12 in the tire axial direction. As a result, the second middle land portion 12 is less likely to be deformed than the first middle land portion 11. Such a first middle land portion 11 and a second middle land portion 12 can make steering response linear when turning on a dry road surface and when the center of the ground contact surface moves to the second tread end side. it can.

  In a more desirable mode, the ratio L2 / W1 of the length L2 of the first middle lateral groove 16 to the width W1 of the first middle land portion 11 and the second middle lateral groove 17 with respect to the width W2 of the second middle land portion 12 are set. The difference between the length L3 and the ratio L3 / W2 is preferably 0.25 to 0.35, for example. As a result, the rigidity balance of the first middle land portion 11 and the second middle land portion 12 becomes appropriate, the steering stability on dry road surface and the snow performance are improved, and the uneven wear of each land portion is suppressed. .

  The second middle lateral groove 17 has, for example, a narrow width portion 17a including a discontinuity in the second middle land portion 12, and a groove width that is continuous with the crown main groove 7 side of the narrow width portion 17a and is larger than the narrow width portion 17a. The widened portion 17b is included. The length of the narrow portion 17a in the tire axial direction is, for example, 0.40 times or more, and preferably 0.45 to 0.60 times, the length L3 of the second middle lateral groove 17 in the tire axial direction.

  The second middle lateral groove 17 preferably has, for example, a shallow bottom portion 17c with a raised bottom surface. In FIG. 2, the shallow bottom portion 17c of one of the second middle lateral grooves 17 is colored. The configuration of the shallow bottom portion 16c of the first middle lateral groove 16 described above can be applied to the shallow bottom portion 17c of the second middle lateral groove 17.

  In the second middle land portion 12, a plurality of non-transverse middle sipes 24 that extend from the crown main groove 7 and are interrupted in the second middle land portion 12 and from the interrupted end of the second middle lateral groove 17 to the second shoulder main groove 6. A plurality of second connection sipes 22 are provided.

  The non-crossing middle sipes 24 are, for example, provided alternately with the second middle lateral grooves 17 in the tire circumferential direction. The non-transverse middle sipes 24 are inclined, for example, in the same direction as the second middle lateral grooves 17 with respect to the tire axial direction. The angle of the non-transverse middle sipes 24 with respect to the tire axial direction is, for example, 10 to 20 °.

  The length L4 of the non-transverse middle sipes 24 in the tire axial direction is preferably, for example, larger than the length L3 of the second middle lateral grooves 17 in the tire axial direction. The non-crossing middle sipe 24 of the present embodiment crosses the center of the second middle land portion 12 in the tire axial direction. Specifically, the length L4 of the non-transverse middle sipe 24 is preferably, for example, 0.50 to 0.90 times the width W2 of the second middle land portion 12 in the tire axial direction. Such a non-crossing middle sipe 24 helps to improve the steering stability and the snow performance in a balanced manner.

  FIG. 6 shows a cross-sectional view of the non-transverse middle sipe 24 of FIG. 2 taken along the line DD. As shown in FIG. 6, the non-transverse middle sipe 24 has, for example, a plurality of shallow bottom sipe portions 25 with a raised bottom surface. The non-crossing middle sipe 24 of the present embodiment includes, for example, a fourth shallow-bottom sipe portion 25d having a raised bottom surface at an end portion on the crown main groove 7 side, a fourth shallow-bottom sipe portion 25d, and a discontinuous end of the non-crossing middle sipe 24. And a fifth shallow bottom sipe portion 25e having a raised bottom surface between.

  In the present embodiment, the depth d6 of the fifth shallow-bottom sipe portion 25e is larger than the depth d5 of the fourth shallow-bottom sipe portion 25d. Such a non-crossing middle sipe 24 effectively suppresses the deformation of the second middle land portion 12 and serves to enhance the steering stability.

  The maximum depth of the non-transverse middle sipes 24 is preferably 0.25 to 0.75 times the depth of the crown main groove 7, for example.

  As shown in FIG. 2, the second connection sipe 22 is inclined in the same direction as the second middle lateral groove 17, for example. The second connection sipe 22 of the present embodiment extends, for example, so as to be smoothly continuous with the edge of the second middle lateral groove 17.

  In the second middle land portion 12, a plurality of second middle chamfered portions which are continuous with the second middle lateral groove 17 and in which a corner portion between the tread surface of the second middle land portion 12 and the side wall on the crown main groove 7 side is recessed 27 are provided. In a desirable mode, the second middle chamfered portion 27 is connected to each second middle lateral groove 17. The second middle chamfered portion 27 is connected to one side (the lower side in FIG. 2) of the second middle lateral groove 17 in the tire circumferential direction.

  The configuration of the first middle chamfered portion 26 described above can be applied to the second middle chamfered portion 27, and description thereof is omitted here.

  The second middle land portion 12 of the present embodiment is not provided with a groove communicating with the second shoulder main groove 6. Further, the second middle land portion 12 is not provided with the chamfered portion on the second shoulder main groove 6 side.

  In the present embodiment, with the above configuration, the rigidity of the second middle land portion 12 in the tire circumferential direction is greater than the rigidity of the first middle land portion 11 in the tire circumferential direction. Accordingly, when turning on a dry road surface, the steering response can be made linear when the center of the ground contact surface moves to the second tread end side.

  FIG. 7 shows an enlarged view of the first shoulder land portion 13. As shown in FIG. 7, the width W4 of the first shoulder land portion 13 in the tire axial direction is 1.10 to 1.70 of the width W1 (shown in FIG. 2) of the first middle land portion 11 in the tire axial direction. It is preferably doubled, and more preferably 1.10 to 1.40 times.

  FIG. 8 shows a sectional view of the first shoulder lateral groove 18 taken along the line EE. As shown in FIG. 8, the first shoulder lateral groove 18 preferably has, for example, a first shoulder shallow bottom portion 31 having a raised bottom surface. The first shoulder shallow bottom portion 31 of the present embodiment is provided, for example, at the end portion of the first shoulder lateral groove 18 on the first shoulder main groove 5 side. Such a first shoulder shallow bottom portion 31 serves to enhance steering stability.

  For easy understanding of the configuration of the first shoulder shallow bottom portion 31, the first shoulder shallow bottom portion 31 is colored for one of the first shoulder lateral grooves 18 shown in FIG. 7. As shown in FIG. 7, the width W5 of the first shallow shoulder portion 31 in the tire axial direction is, for example, 0.10 to 0.20 times the width W4 of the first shoulder land portion 13 in the tire axial direction. The first shoulder shallow bottom portion 31 as described above can increase the rigidity of the first shoulder land portion 13 while maintaining snow performance.

  The first shoulder land portion 13 has a plurality of first shoulders which are continuous with the first shoulder lateral groove 18 and in which a corner portion between the tread surface of the first shoulder land portion 13 and the side wall on the first shoulder main groove 5 side is recessed. A chamfer 28 is provided. Further, the first shoulder chamfered portion 28 is continuous with the other side (the upper side in FIG. 7) of the first shoulder lateral groove 18 in the tire circumferential direction.

  The first shoulder chamfered portion 28 has a cross-sectional shape similar to that of the above-mentioned first middle chamfered portion 26, and a description thereof will be omitted here.

  It is preferable that at least one of the first middle chamfered portions 26 partially or wholly faces the first shoulder chamfered portion 28 in the tire axial direction. Thereby, the substantial opening width of the first shoulder main groove 5 is partially enlarged. Therefore, when traveling on snow, a large amount of snow is taken into this region to generate a hard snow column, and thus a large snow column shear force is obtained.

  The distance L5 in the tire circumferential direction from the end of the first middle chamfered portion 26 on one side in the tire circumferential direction to the end of the first shoulder chamfered portion 28 on the other side in the tire circumferential direction is equal to the tire of the first shoulder chamfered portion 28. It is preferably 0.60 to 0.90 times the length L8 in the circumferential direction. The arrangement of such chamfered portions serves to suppress uneven wear of the first middle land portion 11 and the first shoulder land portion 13.

  The first shoulder chamfered portion 28 of the present embodiment is provided at the projecting corner portion where the angle between the first shoulder main groove 5 and the first shoulder lateral groove 18 is an obtuse angle. In other words, the first shoulder lateral groove 18 is inclined toward the one side in the tire circumferential direction from the first shoulder main groove 5 toward the first tread end Te1, and the first shoulder chamfered portion 28 is the first shoulder lateral groove. 18 is connected to the other side in the tire circumferential direction.

  Regarding the first middle lateral groove 16 and the first shoulder lateral groove 18 whose chamfers face each other, the maximum angle of the first middle lateral groove 16 with respect to the tire axial direction is greater than the maximum angle of the first shoulder lateral groove 18 with respect to the tire axial direction. Larger is desirable. With such an arrangement of the lateral grooves, the first middle lateral groove 16 also provides a snow column shearing force in the tire axial direction, and enhances the turning performance on snow.

  In the first shoulder land portion 13 of the present embodiment, a first shoulder lateral groove 18 continuous with the first shoulder chamfered portion 28 and a first shoulder lateral groove 18 not continuous with the first shoulder chamfered portion 28 are arranged in the tire circumferential direction. They are provided alternately. In the first middle land portion 11 of the present embodiment, a first middle chamfered portion 26 facing the first shoulder chamfered portion 28 and a first middle chamfered portion 26 not facing the first shoulder chamfered portion 28. Are provided alternately in the tire circumferential direction. Such arrangement of the chamfered portions can prevent the ground contact area of the first shoulder land portion 13 from being excessively reduced by the first shoulder chamfered portion 28.

  The first shoulder land portion 13 of the present embodiment is provided with, for example, a plurality of first shoulder sipes 36 and a plurality of first short sipes 38.

  The first shoulder sipe 36 extends, for example, outward from the first shoulder main groove 5 in the tire axial direction. The 1st shoulder sipe 36 of this embodiment is interrupted in the 1st shoulder land part 13, for example. Such a first shoulder sipe 36 maintains the rigidity of the first shoulder land portion 13 and provides a frictional force by its edge.

  The first shoulder sipe 36 extends, for example, along the first shoulder lateral groove 18. The length L6 of the first shoulder sipe 36 in the tire axial direction is, for example, 0.55 to 0.75 times the width W4 of the first shoulder land portion 13 in the tire axial direction. Further, the maximum depth of the first shoulder sipe 36 is preferably 0.25 to 0.75 times the depth of the first shoulder main groove 5, for example.

  The first short sipe 38 extends from the first tread end Te1 and is interrupted in the first shoulder land portion 13, for example. The first short sipe 38 of the present embodiment is provided, for example, on an extension line of the first shoulder sipe 36. In the present embodiment, a gap of 1 to 10 mm is formed between the first shoulder sipe 36 and the first short sipe 38. The first short sipe 38 as described above, together with the first shoulder sipe 36, provides the frictional force while maintaining the rigidity of the first shoulder land portion 13.

  FIG. 9 shows an enlarged view of the second shoulder land portion 14. As shown in FIG. 9, the width W6 of the second shoulder land portion 14 in the tire axial direction is 1.10 to 1.70 of the width W2 (shown in FIG. 2) of the second middle land portion 12 in the tire axial direction. It is preferably doubled, and more preferably 1.10 to 1.40 times. In this embodiment, the first shoulder land portion 13 and the second shoulder land portion 14 are formed with the same width.

  The second shoulder lateral groove 19 preferably has, for example, a second shoulder shallow bottom portion 32 having a raised bottom surface. The second shoulder shallow bottom portion 32 has substantially the same configuration as the first shoulder shallow bottom portion 31 except for the matters described below. Therefore, the configuration of the first shoulder shallow bottom portion 31 can be applied to the second shoulder shallow bottom portion 32.

  In FIG. 9, the second shoulder shallow bottom portion 32 is colored for one of the second shoulder lateral grooves 19 so that the configuration of the second shoulder shallow bottom portion 32 can be easily understood. The second shoulder shallow bottom portion 32 of the present embodiment is provided, for example, at the end portion of the second shoulder lateral groove 19 on the second shoulder main groove 6 side.

  The width W7 of the second shoulder shallow bottom portion 32 in the tire axial direction is preferably larger than the width W5 of the first shoulder shallow bottom portion 31 in the tire axial direction, for example. Specifically, the width W7 of the second shoulder shallow bottom portion 32 is 1.5 to 2.5 times the width W5 of the first shoulder shallow bottom portion 31. Such a second shoulder shallow bottom portion 32 enhances the rigidity of the second shoulder land portion 14 and can exhibit excellent steering stability.

  In the second shoulder land portion 14, a plurality of second shoulders that are continuous with the second shoulder lateral groove 19 and have a recessed corner portion between the tread surface of the second shoulder land portion 14 and the side wall on the second shoulder main groove 6 side. A chamfer 29 is provided. In addition, the second shoulder chamfered portion 29 is continuous with one side (the lower side in FIG. 9) of the second shoulder lateral groove 19 in the tire circumferential direction. Such a second shoulder chamfer 29 provides a snow column shearing force together with the second shoulder main groove 6 when traveling on snow.

  The second shoulder chamfered portion 29 has the same cross-sectional shape as the above-described first middle chamfered portion 26, and the description thereof is omitted here.

  In the second shoulder land portion 14 of the present embodiment, a second shoulder lateral groove 19 continuous with the second shoulder chamfered portion 29 and a second shoulder lateral groove 19 not continuous with the second shoulder chamfered portion 29 are arranged in the tire circumferential direction. They are provided alternately. This can prevent the ground contact area of the second shoulder land portion 14 from being excessively reduced by the second shoulder chamfered portion 29.

  The second shoulder land portion 14 of the present embodiment is provided with, for example, a plurality of second shoulder sipes 37 and a plurality of second short sipes 39.

  For example, both ends of the second shoulder sipe 37 are interrupted within the second shoulder land portion 14. The minimum distance from the second shoulder main groove 6 to the second shoulder sipe 37 is preferably, for example, 2 to 20 mm. The length L7 of the second shoulder sipe 37 in the tire axial direction is, for example, 0.50 to 0.70 times the width W6 of the second shoulder land portion 14 in the tire axial direction. Further, the maximum depth of the second shoulder sipe 37 is preferably, for example, 0.25 to 0.75 times the depth of the second shoulder main groove 6.

  The second short sipe 39 extends, for example, from the second tread end Te2 and is interrupted in the second shoulder land portion 14. The second short sipe 39 of the present embodiment is provided, for example, on an extension of the second shoulder sipe 37. In the present embodiment, a gap of 1 to 10 mm is formed between the second shoulder sipe 37 and the second short sipe 39.

  In the present embodiment, the rigidity of the second shoulder land portion 14 in the tire circumferential direction is greater than the rigidity of the first shoulder land portion 13 in the tire circumferential direction due to the above configuration. Accordingly, when turning on a dry road surface, when the center of the ground contact surface moves to the second tread end side, the steering response becomes linear, and excellent steering stability is obtained. On the contrary, when the rigidity of the first shoulder land portion 13 in the tire circumferential direction is larger than the rigidity of the second shoulder land portion 14 in the tire circumferential direction, the self-aligning torque becomes small, and the response during steering deteriorates. It tends to impair steering stability.

  Although the tire according to the embodiment of the present invention has been described above in detail, the present invention is not limited to the specific embodiment described above, and may be carried out in various modes.

A tire of size 165 / 65R14 having the basic pattern of FIG. 1 was prototyped. As a comparative example, as shown in FIG. 10, a tire in which a lateral groove b extending from the first tread end Te1 and interrupted in the first shoulder land portion a was provided in the first shoulder land portion a was experimentally manufactured. The pattern of the tread portion of the tire of the comparative example is substantially the same as that shown in FIG. 1 except for the above matters. Each test tire was tested for steering stability on dry road surface and snow performance. The common specifications and test methods for each test tire are as follows.
Mounting rim: 14 × 4.5J
Tire pressure: 240kPa front wheel, 240kPa rear wheel
Test vehicle: Displacement 1300cc, front-wheel drive vehicle Tire mounting position: All wheels

<Stability on dry roads>
The driving stability of the test vehicle when running on a dry road surface was evaluated by the driver's sensory sense. The result is a score with Comparative Example being 100, and shows that the larger the value is, the more excellent the steering stability on a dry road surface is.

<Snow performance>
The driving characteristics of the traction performance, the braking performance, and the turning performance when traveling on a snowy road in the test vehicle equipped with each test tire were evaluated by the driver's sensory sense. The results are scores with Comparative Example being 100, and the larger the value, the better the snow performance.
The test results are shown in Table 1.

  As a result of the test, it was confirmed that the tires of Examples had improved steering stability on dry road surfaces and snow performance.

2 tread portion 3 main groove 4 land portion 5 first shoulder main groove 6 second shoulder main groove 7 crown main groove 11 first middle land portion 12 second middle land portion 13 first shoulder land portion 14 second shoulder land portion 16 First middle lateral groove 17 Second middle lateral groove 18 First shoulder lateral groove 19 Second shoulder lateral groove C Tire equator Te1 First tread end Te2 Second tread end

As shown in FIG. 1, the tire 1 of the present invention has a tread portion 2 in which a mounting direction in a vehicle is designated. The tread portion 2 has a first tread edge Te1 located on the vehicle in the side of the vehicle when mounting the tire 1 and a second tread edge Te2 located on the vehicle outside side when mounted to a vehicle. The direction of mounting on the vehicle is displayed, for example, in characters or symbols on the sidewall portion (not shown).

Claims (10)

A tire having a tread portion whose direction of attachment to a vehicle is designated,
The tread portion includes a first tread end located inside the vehicle when the vehicle is mounted, a second tread end located outside the vehicle when the vehicle is mounted, and a tire circumference between the first tread end and the second tread end. Having a plurality of main grooves continuously extending in the direction, and a plurality of land portions divided into the main grooves,
The main groove, a first shoulder main groove arranged between the first tread end and a tire equator, a second shoulder main groove arranged between the second tread end and a tire equator, and Including one crown main groove arranged between the first shoulder main groove and the second shoulder main groove,
The land portion includes a first middle land portion that is partitioned between the first shoulder main groove and the crown main groove, and a second middle land portion that is partitioned between the second shoulder main groove and the crown main groove. A middle land portion, a first shoulder land portion that is partitioned between the first shoulder main groove and the first tread end, and a second shoulder main groove and the second tread end. Including the second shoulder land portion,
The first middle land portion is provided with a plurality of first middle lateral grooves extending from the first shoulder main groove and interrupted in the first middle land portion,
The second middle land portion is provided with a plurality of second middle lateral grooves extending from the crown main groove and interrupting in the second middle land portion.
The first shoulder land portion is provided with a plurality of first shoulder lateral grooves that completely traverse the first shoulder land portion,
The second shoulder land portion is provided with a plurality of second shoulder lateral grooves that completely traverse the second shoulder land portion.
tire. Each of the first middle lateral groove and the second middle lateral groove is inclined in the first direction with respect to the tire axial direction,
The tire according to claim 1, wherein each of the first shoulder lateral groove and the second shoulder lateral groove is inclined in a second direction opposite to the first direction with respect to a tire axial direction.   The tire according to claim 1 or 2, wherein the second middle land portion is provided with a plurality of non-transverse middle sipes extending from the crown main groove and interrupting in the second middle land portion.   The tire according to claim 3, wherein a length of the non-crossing middle sipes in the tire axial direction is 0.50 to 0.90 times a width of the second middle land portion in the tire axial direction.   The tire according to any one of claims 1 to 4, wherein the first middle land portion is provided with a plurality of transverse middle sipes extending from the first shoulder main groove to the crown main groove.   The tire according to any one of claims 1 to 5, wherein the first shoulder land portion is provided with a plurality of first shoulder sipes extending from the first shoulder main groove outward in the tire axial direction.   The tire according to any one of claims 1 to 6, wherein the second shoulder land portion is provided with a plurality of second shoulder sipes whose both ends are interrupted in the second shoulder land portion.   The tire according to claim 7, wherein the minimum distance from the second shoulder main groove to the second shoulder sipe is 2 to 20 mm.   The tire according to claim 1, wherein a rigidity of the second middle land portion in a tire circumferential direction is higher than a rigidity of the first middle land portion in a tire circumferential direction.   The tire according to claim 1, wherein a rigidity of the second shoulder land portion in a tire circumferential direction is higher than a rigidity of the first shoulder land portion in a tire circumferential direction.

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