WO2015167007A1 - Pneumatique - Google Patents

Pneumatique Download PDF

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Publication number
WO2015167007A1
WO2015167007A1 PCT/JP2015/063063 JP2015063063W WO2015167007A1 WO 2015167007 A1 WO2015167007 A1 WO 2015167007A1 JP 2015063063 W JP2015063063 W JP 2015063063W WO 2015167007 A1 WO2015167007 A1 WO 2015167007A1
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WO
WIPO (PCT)
Prior art keywords
block
tire
groove
circumferential main
sipe
Prior art date
Application number
PCT/JP2015/063063
Other languages
English (en)
Japanese (ja)
Inventor
英樹 浜中
Original Assignee
横浜ゴム株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 横浜ゴム株式会社 filed Critical 横浜ゴム株式会社
Priority to CN201580021587.7A priority Critical patent/CN106457922B/zh
Publication of WO2015167007A1 publication Critical patent/WO2015167007A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/03—Tread patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/03—Tread patterns
    • B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C11/00—Tyre tread bands; Tread patterns; Anti-skid inserts
    • B60C11/03—Tread patterns
    • B60C11/12—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes
    • B60C11/1236—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special arrangements in the tread pattern
    • B60C2011/1254—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special arrangements in the tread pattern with closed sipe, i.e. not extending to a groove

Definitions

  • the present invention relates to a pneumatic tire, and more particularly to a pneumatic tire that can improve uneven wear resistance of the tire.
  • the present invention has been made in view of the above, and an object thereof is to provide a pneumatic tire capable of improving the uneven wear resistance of the tire.
  • a pneumatic tire according to the present invention includes a plurality of circumferential main grooves extending in the tire circumferential direction, and a plurality of land portions defined by the circumferential main grooves.
  • the outer circumferential main groove that is the outermost in the tire width direction is referred to as an outermost circumferential main groove
  • the land portion on the inner side in the tire width direction defined by the outermost circumferential main groove is a center land portion.
  • the center land portions When at least one row of the center land portions includes a plurality of lug grooves extending in the tire width direction, and a plurality of blocks defined by the plurality of lug grooves, the circumference of the blocks
  • the left and right edge portions on the direction main groove side have a step shape having an amplitude in the tire width direction
  • the front and rear edge portions on the lug groove side of the block have a step shape having an amplitude in the tire circumferential direction.
  • Each of the hooks has a plurality of sipes extending in the tire width direction, and 80% of the sipes formed in one of the blocks are opened in the circumferential main groove at one end.
  • the direction length Wb has a relationship of 0.30 ⁇ P / Wb ⁇ 0.60.
  • the concentration P / Wb of the projected length P of the semi-closed sipe and the length Wb in the width direction of the block is optimized, so that stress concentration at the edge portion of the block is moderated appropriately.
  • FIG. 1 is a sectional view in the tire meridian direction showing a pneumatic tire according to an embodiment of the present invention.
  • FIG. 2 is a plan view showing a tread surface of the pneumatic tire depicted in FIG. 1.
  • FIG. 3 is a plan view showing a center land portion of the tread pattern shown in FIG. 4 is a cross-sectional view showing a lug groove in the center land portion shown in FIG.
  • FIG. 5 is a cross-sectional view showing a cutout portion of the block shown in FIG. 3.
  • FIG. 6 is a cross-sectional view showing a sipe of the block shown in FIG.
  • FIG. 7 is an explanatory diagram illustrating an example of a three-dimensional sipe.
  • FIG. 1 is a sectional view in the tire meridian direction showing a pneumatic tire according to an embodiment of the present invention.
  • FIG. 2 is a plan view showing a tread surface of the pneumatic tire depicted in FIG. 1.
  • FIG. 3 is a plan view
  • FIG. 8 is an explanatory diagram illustrating an example of a three-dimensional sipe.
  • FIG. 9 is a chart showing the results of the performance test of the pneumatic tire according to the embodiment of the present invention.
  • FIG. 10 is a chart showing the results of the performance test of the pneumatic tire according to the embodiment of the present invention.
  • FIG. 1 is a sectional view in the tire meridian direction showing a pneumatic tire according to an embodiment of the present invention. This figure shows one side region in the tire radial direction. The figure shows a small truck studless tire as an example of a pneumatic tire. In the figure, the symbol CL is the tire equator plane.
  • the tire width direction means a direction parallel to a tire rotation axis (not shown), and the tire radial direction means a direction perpendicular to the tire rotation axis.
  • the pneumatic tire 1 has an annular structure centered on the tire rotation axis, and includes a pair of bead cores 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, and a tread rubber 15. And a pair of sidewall rubbers 16 and 16 and a pair of rim cushion rubbers 17 and 17 (see FIG. 1).
  • the pair of bead cores 11 and 11 is an annular member formed by bundling a plurality of bead wires, and constitutes the core of the left and right bead portions.
  • the pair of bead fillers 12 and 12 are disposed on the outer periphery in the tire radial direction of the pair of bead cores 11 and 11 to reinforce the bead portion.
  • the carcass layer 13 is bridged in a toroidal shape between the left and right bead cores 11 and 11 to form a tire skeleton. Further, both end portions of the carcass layer 13 are wound and locked outward in the tire width direction so as to wrap the bead core 11 and the bead filler 12.
  • the carcass layer 13 is formed by rolling a plurality of carcass cords made of steel or an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) with a coat rubber, and has an absolute value of 80 [deg].
  • a carcass angle of 95 [deg] or less inclination angle in the fiber direction of the carcass cord with respect to the tire circumferential direction).
  • the belt layer 14 is formed by laminating a pair of cross belts 141 and 142 and a belt cover 143, and is arranged around the outer periphery of the carcass layer 13.
  • the pair of cross belts 141 and 142 is formed by rolling a plurality of belt cords made of steel or organic fiber material with a coating rubber, and has an absolute value of a belt angle of 20 [deg] or more and 40 [deg] or less.
  • the pair of cross belts 141 and 142 have belt angles with different signs from each other (inclination angle of the fiber direction of the belt cord with respect to the tire circumferential direction), and are laminated so that the fiber directions of the belt cords cross each other. (Cross ply structure).
  • the belt cover 143 is formed by rolling a plurality of belt cords made of steel or organic fiber material coated with a coat rubber, and has a belt angle of 45 [deg] or more and 70 [deg] or less in absolute value. Further, the belt cover 143 is disposed so as to be laminated on the outer side in the tire radial direction of the cross belts 141 and 142.
  • the tread rubber 15 is disposed on the outer circumference in the tire radial direction of the carcass layer 13 and the belt layer 14 to constitute a tread portion of the tire.
  • the pair of side wall rubbers 16 and 16 are respectively arranged on the outer side in the tire width direction of the carcass layer 13 to constitute left and right side wall portions.
  • the pair of rim cushion rubbers 17 and 17 are arranged on the outer sides in the tire width direction of the left and right bead cores 11 and 11 and the bead fillers 12 and 12, respectively, and constitute left and right bead portions.
  • the tread rubber 15 (particularly the cap rubber constituting the tread surface) preferably has a rubber hardness of 50 or more and 75 or less, and more preferably 60 or more and 70 or less.
  • Rubber hardness refers to JIS-A hardness according to JIS-K6263, and is measured under the condition of 20 [° C.].
  • FIG. 2 is a plan view showing a tread surface of the pneumatic tire depicted in FIG. 1.
  • the figure shows the traction pattern of the studless tire.
  • the tire circumferential direction refers to the direction around the tire rotation axis.
  • symbol T is a tire grounding end.
  • the pneumatic tire 1 includes a plurality of circumferential main grooves 21 and 22 extending in the tire circumferential direction, and a plurality of land portions defined by the circumferential main grooves 21 and 22. 31 to 33 and a plurality of lug grooves 41 to 44 extending in the tire width direction are provided in the tread portion.
  • Reference numeral 23 denotes a circumferential narrow groove.
  • the circumferential main groove is a circumferential groove having a wear indicator indicating the end of wear, and generally has a groove width of 5.0 [mm] or more and a groove depth of 7.5 [mm] or more.
  • the groove width is measured as the maximum value of the distance between the left and right groove walls at the groove opening in a no-load state in which the tire is mounted on the specified rim and filled with the specified internal pressure.
  • the groove width is based on the intersection of the tread surface and the extension line of the groove wall in a cross-sectional view in which the groove length direction is a normal direction. Measured.
  • the groove width is measured with reference to the center line of the amplitude of the groove wall.
  • the groove depth is measured as the maximum value of the distance from the tread surface to the groove bottom in an unloaded state in which the tire is mounted on the specified rim and filled with the specified internal pressure. Moreover, in the structure which a groove
  • Specified rim means “Applied rim” defined in JATMA, “Design Rim” defined in TRA, or “Measuring Rim” defined in ETRTO.
  • the specified internal pressure means “maximum air pressure” specified by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFLATIONLPRESSURES” specified by TRA, or “INFLATION PRESSURES” specified by ETRTO.
  • the specified load means the “maximum load capacity” defined by JATMA, the maximum value of “TIRE LOAD LIMITS AT VARIOUS COLD INFUREATION PRESSURES” prescribed by TRA, or “LOAD CAPACITY” prescribed by ETRTO.
  • the specified internal pressure is air pressure 180 [kPa]
  • the specified load is 88 [%] of the maximum load capacity.
  • the left and right circumferential main grooves 22 and 22 on the outermost side in the tire width direction are referred to as outermost circumferential main grooves.
  • the land portions 31 and 32 located on the inner side in the tire width direction from the left and right outermost circumferential main grooves 22 and 22 are referred to as center land portions.
  • the land portions 33, 33 located on the outer side in the tire width direction from the left and right outermost circumferential main grooves 22, 22 are referred to as shoulder land portions.
  • the four circumferential main grooves 21 and 22 are arranged symmetrically about the tire equatorial plane CL.
  • the circumferential main grooves 21 and 22 define three rows of center land portions 31, 32 and 32 and a pair of left and right shoulder land portions 33 and 33. Further, left and right shoulder land portions 33 and 33 are disposed on the left and right tire ground contact ends T and T, respectively.
  • the present invention is not limited to this, and the circumferential main grooves 21 and 22 may be arranged asymmetrically about the tire equatorial plane CL (not shown). Further, the circumferential main groove may be disposed on the tire equatorial plane CL (not shown). Three or more circumferential main grooves may be arranged (not shown).
  • FIG. 3 is a plan view showing a center land portion of the tread pattern shown in FIG. The figure shows an enlarged plan view of the block 5 of the center land portion 31.
  • the pneumatic tire 1 includes three rows of center land portions 31 and 32, and these center land portions 31 and 32 have the same structure. Therefore, in this embodiment, as an example, the center center land portion 31 will be described, and description of the other center land portions 32, 32 will be omitted.
  • the center land portion 31 (32) has a plurality of lug grooves 41 (42) extending in the tire width direction and a plurality of blocks that are partitioned by these lug grooves 41. And 5.
  • a plurality of lug grooves 41 penetrate the center land portion 31 in the tire width direction and open to the left and right circumferential main grooves 21 and 21 that define the center land portion 31, respectively.
  • a plurality of lug grooves 41 are arranged at predetermined intervals in the tire circumferential direction. Thereby, the center land portion 31 is divided in the tire circumferential direction by the lug grooves 41 to form a block row composed of a plurality of blocks 5.
  • all the land portions 31 to 33 each have a plurality of lug grooves 41 to 44 extending in the tire width direction, and these lug grooves 41 to 44 are land portions 31 to 33. Has an open structure that penetrates through the tire in the tire width direction. For this reason, all the land portions 31 to 33 form a block row.
  • the present invention is not limited to this, and for example, the lug groove 43 of the shoulder land portion 33 may have a semi-closed structure that terminates in the land portion 33 at one end portion (not shown).
  • the shoulder land portion 33 is a rib continuous in the tire circumferential direction.
  • the left and right edge portions on the circumferential main grooves 21 and 21 side of the block 5 have a step shape having an amplitude in the tire width direction.
  • the traction component of the center land part 31 increases, and the performance on ice and the performance on snow of a tire improve.
  • the left and right edge portions on the circumferential main grooves 21 and 21 side of the block 5 have a step shape having two steps (reference numerals omitted). Further, these steps have a linear shape substantially parallel to the tire circumferential direction on the block tread surface, and are arranged offset from each other in the tire width direction. Further, the step-shaped stepped portion (not shown) is 40 [%] or more and 60 [%] or less with respect to the central portion of the block 5 (the circumferential length Lb of the edge portion on the circumferential main groove 21 side of the block 5). In the area).
  • the steps of the edge portions of the blocks 5 and 5 adjacent in the tire circumferential direction are arranged offset in the tire width direction with the lug groove 41 interposed therebetween.
  • the edge part by the side of the circumferential direction main groove 21 of the center land part 31 has the step shape extended in a tire circumferential direction, changing to a step shape in a tire width direction.
  • the step amount of the step shape of the block 5 (dimension code omitted) is set to about 2 [mm].
  • the front and rear edge portions on the lug groove 41 side of the block 5 have a step shape having an amplitude in the tire circumferential direction. Thereby, the traction component of the center land part 31 increases, and the performance on ice and the performance on snow of a tire improve.
  • the lug groove 41 extends in the tire width direction while being bent, so that the edge portion on the lug groove 41 side of the block 5 has a step shape having two steps (reference numerals omitted). ing. Also, these steps are arranged offset from each other in the groove width direction of the lug groove 41. Further, the step-shaped stepped portion 53 of the block 5 is an area of 40 [%] or more and 60 [%] or less with respect to the central portion of the block 5 (the width direction length Wb of the edge portion of the block 5 on the lug groove 41 side). ).
  • the lug groove 41 extends while inclining at a predetermined angle in the tire width direction, so that the step-shaped step of the block 5 is inclined with respect to the tire width direction as a whole.
  • the inclination angle of the lug groove 41 with respect to the tire width direction is preferably in the range of 1 [deg] or more and 30 [deg] or less.
  • the inclination angle of the lug groove 41 is measured as an angle formed by a straight line passing through the center point of the left and right openings of the lug groove 41 and the tire width direction.
  • the circumferential length Lb of the edge portion on the circumferential main groove 21 side of the block 5 and the width direction length Wb of the edge portion on the lug groove 41 side of the block 5 are 1.15 ⁇ Lb / Wb ⁇ 1. .50 relationship. Thereby, the shape of the block 5 is optimized.
  • the circumferential length Lb of the block 5 is the distance in the tire circumferential direction of the edge portion of the block 5 facing the circumferential main groove 21, and the tire is mounted on the prescribed rim to apply the prescribed internal pressure and to be in an unloaded state. Measured. Moreover, in the structure where the edge part of the block 5 has a chamfer part or a notch part, these are excluded and the circumferential direction length Lb is measured.
  • the width direction length Wb of the block 5 is a distance in the tire width direction of the edge portion of the block 5 facing the lug groove 41, and is measured as an unloaded state while applying a specified internal pressure by mounting the tire on a specified rim.
  • the lug groove 41 is inclined with respect to the tire width direction, so that the tread surface of the block 5 has a parallelogram shape as a whole.
  • a chamfered portion (reference numeral omitted) is applied to the acute corner portion of the block 5.
  • width direction length Wb of the edge portion on the lug groove 41 side of the block 5 and the tire ground contact width TW have a relationship of 0.10 ⁇ Wb / TW ⁇ 0.18. Thereby, the width direction length Wb of the block 5 is optimized.
  • the tire ground contact width TW is the contact surface between the tire and the flat plate when the tire is mounted on the specified rim to apply the specified internal pressure and is placed perpendicular to the flat plate in a stationary state and applied with a load corresponding to the specified load. It is measured as the maximum linear distance in the tire axial direction.
  • the lug groove 41 opens with a see-through structure to the left and right circumferential main grooves 21, 21 that define the center land portion 31.
  • the see-through structure refers to a structure in which the other circumferential main groove 21 can be seen from one circumferential main groove 21 via the lug groove 41. Such a see-through structure improves the drainage performance and snow removal performance of the lug groove 41.
  • the opening width Wl in the tire circumferential direction of the lug groove 41 and the circumferential length Lb of the edge portion on the circumferential main groove 21 side of the block 5 have a relationship of 0.08 ⁇ Wl / Lb ⁇ 0.18. Preferably, it has a relationship of 0.10 ⁇ Wl / Lb ⁇ 0.15. Thereby, the opening width Wl of the lug groove 41 is optimized.
  • the opening width Wl of the lug groove 41 is a distance in the tire circumferential direction of the opening with respect to the circumferential main groove 21 of the lug groove 41, and is measured as a no-load state while attaching the tire to the specified rim and applying the specified internal pressure.
  • the lug groove 41 generally has a groove width of 1.0 [mm] or more.
  • the groove width of the lug groove 41 is measured by excluding the chamfered part and the notch part at the edge part of the block 5.
  • FIG. 4 is a cross-sectional view showing the lug groove in the center land portion shown in FIG. This figure shows a cross-sectional view of the lug groove 41 in the groove depth direction.
  • the lug groove 41 has a bottom upper portion 411.
  • the bottom upper part 411 is formed at the groove bottom of the lug groove 41 and partially raises the groove depth of the lug groove 41. Thereby, the rigidity of the block 5 is ensured and uneven wear of the block 5 is suppressed.
  • the groove depth DL of the lug groove 41 in the bottom upper portion 411 and the groove depth GD of the circumferential main groove 21 preferably have a relationship of 0.50 ⁇ DL / GD ⁇ 0.80. It is more preferable to have a relationship of 55 ⁇ DL / GD ⁇ 0.75. Thereby, the groove depth DL of the lug groove 41 in the bottom upper part 411 is optimized.
  • the bottom upper portion 411 of the lug groove 41 is formed at the center of the lug groove 41 in the groove length direction. Further, the groove depth of the lug groove 41 gradually increases from the bottom upper portion 411 toward the circumferential main groove 21, and becomes maximum at the groove opening portion with respect to the circumferential main groove 21. Thereby, the drainage property of the lug groove 41 and the snow drainage property are improved.
  • FIG. 5 is a cross-sectional view showing a cutout portion of the block shown in FIG. 3. This figure shows a sectional view of the notch 52 in the depth direction.
  • the block 5 of the center land portion 31 has a cutout portion 52 at an edge portion on the circumferential main groove 21 side. Further, the notch 52 is formed in the stepped step portion of the block 5. Thereby, the slip amount of the edge part of the block 5 at the time of tire contact is made uniform, and the uneven wear of the block 5 is suppressed.
  • the block 5 of the center land portion 31 has notches 52 at the edge portions on the left and right circumferential main grooves 21, 21 side. Further, as described above, the left and right edge portions of the block 5 each have a step shape having two steps, and the notch portions 52 are respectively disposed at the step portions of these steps.
  • the circumferential length Lb of the edge portion on the circumferential main groove 21 side of the block 5 and the position Mc of the notch 52 in the edge portion of the block 5 are 0.35 ⁇ Mc / Lb ⁇ 0. .65, preferably 0.40 ⁇ Mc / Lb ⁇ 0.60. Thereby, the position Mc of the notch 52 is optimized.
  • the position Mc of the notch 52 is measured as a distance in the tire circumferential direction between the measurement point of the circumferential length Lb of the block 5 and the center of the notch 52 in a plan view of the block 5.
  • the depth Dc of the notch 52 and the groove depth GD of the circumferential main groove 21 preferably have a relationship of 0.50 ⁇ Dc / GD ⁇ 0.80, It is more preferable to have a relationship of ⁇ Dc / GD ⁇ 0.75. Thereby, the depth Dc of the notch 52 is optimized.
  • the depth Dc of the notch 52 is measured as the maximum depth of the notch 52 with reference to the tread surface of the block 5.
  • the width direction length Wc of the notch 52 and the width direction length Wb of the edge portion on the lug groove 41 side of the block 5 have a relationship of 0.05 ⁇ Wc / Wb ⁇ 0.25. It is preferable to have. Thereby, the function of the notch 52 is ensured and the rigidity of the block 5 is ensured.
  • the width direction length Wc of the notch portion 52 is measured as a length in the tire width direction with reference to the step of the edge portion on the circumferential main groove 21 side of the step shape of the block 5.
  • FIG. 6 is a cross-sectional view showing a sipe of the block shown in FIG. This figure shows a sectional view of the sipe 51 in the depth direction.
  • the block 5 of the center land portion 31 has a plurality of sipes 51 extending in the tire width direction. Further, an 80% sipe 51 formed in one block 5 is a semi-closed sipe (one-side opening sipe), and opens to the circumferential main groove 21 at one end and the other end. End in block 5 at. Thereby, the edge component of the block 5 increases and the traction performance as a studless tire is improved.
  • Sipe refers to a cut having a sipe width of less than 1.0 [mm].
  • one block 5 has a plurality of semi-closed sipes 51 and a plurality of closed sipes (reference numerals omitted) that terminate inside the block 5 at both ends.
  • the ratio of the semi-closed sipe 51 in one block 5 is set to 80 [%] or more with respect to the total number of sipes.
  • the plurality of semi-closed sipes 51 have a zigzag shape extending in the tire width direction, and are arranged at substantially uniform intervals in the tire circumferential direction. Further, the plurality of semi-closed sipes 51 are equally arranged on the left and right edge portions of the block 5. Thereby, the rigidity of the left and right edge portions of the block 5 is made uniform.
  • the block 5 of the center land portion 31 does not have an open sipe that penetrates the block 5.
  • the tread surface of the block 5 has a structure which continues in the tire circumferential direction without being divided by sipes. Thereby, the rigidity of the block 5 is improved.
  • the projection length P of the semi-closed sipe 51 in the tire circumferential direction and the width-direction length Wb of the edge portion on the lug groove 41 side of the block 5 have a relationship of 0.30 ⁇ P / Wb ⁇ 0.60. Respectively.
  • the ratio P / Wb is preferably in the range of 0.35 ⁇ P / Wb ⁇ 0.55.
  • the semi-closed sipe 51 that satisfies the condition P / Wb is set to 80 [%] or more with respect to the total number of sipes in one block 5. Thereby, the projection length P of the sipe 51 is optimized.
  • the sipe projection length P is measured based on the sipe length on the tread surface of the block 5.
  • the sipe depth Ds1 of the semi-closed sipe 51 and the groove depth GD of the circumferential main groove 21 preferably have a relationship of 0.55 ⁇ Ds1 / GD ⁇ 0.85. It is more preferable to have a relationship of 60 ⁇ Ds1 / GD ⁇ 0.80. Thereby, the sipe depth Ds1 is optimized.
  • the sipe depth Ds1 is measured as a distance from the tread surface of the block 5 to the maximum depth position of the sipe 51.
  • the semi-closed sipe 51 has a bottom upper portion 511 at an opening portion with respect to the circumferential main groove 21.
  • the sipe depth Ds2 in the bottom upper portion 511 and the groove depth GD of the circumferential main groove 21 preferably have a relationship of 0.05 ⁇ Ds2 / GD ⁇ 0.25, and 0.10 ⁇ Ds2 It is more preferable to have a relationship of /GD ⁇ 0.20. Thereby, the sipe depth Ds2 in the bottom upper part 511 is optimized.
  • the sipe depth Ds2 at the bottom upper part 511 is measured with reference to the tread surface of the block 5.
  • the arrangement length Ws of the bottom upper portion 511 and the width direction length Wb of the edge portion on the lug groove 41 side of the block 5 have a relationship of 0.05 ⁇ Ws / Wb ⁇ 0.20. It is preferable. Thereby, the arrangement
  • the arrangement length Ws of the bottom upper part 511 is measured as the length in the tire width direction of the bottom upper part 511 in the plan view of the block 5.
  • the sipe may be a two-dimensional sipe or a three-dimensional sipe.
  • all the sipes of the center land portion 31 are three-dimensional sipes.
  • a two-dimensional sipe is a sipe having a sipe wall surface that is linear in a sectional view (a sectional view including a sipe width direction and a sipe depth direction) with the sipe length direction as a normal direction.
  • the two-dimensional sipe may have a straight shape on the tread surface, a zigzag shape, a wave shape, or an arc shape.
  • a three-dimensional sipe is a sipe having a sipe wall surface that is bent in the sipe width direction in a cross-sectional view with the sipe length direction as the normal direction. Compared to the two-dimensional sipe, the three-dimensional sipe has a strong meshing force between the opposing sipe wall surfaces, so that the collapse of the block at the time of tire contact is effectively suppressed.
  • the three-dimensional sipe may have a straight shape on the tread surface, a zigzag shape, a wave shape, or an arc shape. Examples of such a three-dimensional sipe include the following (see FIGS. 7 and 8).
  • FIG. 7 and 8 are explanatory diagrams showing an example of a three-dimensional sipe. These figures show the sipe wall surface of the three-dimensional sipe.
  • the sipe wall surface has a structure in which a triangular pyramid and an inverted triangular pyramid are connected in the sipe length direction.
  • the sipe wall surface has a zigzag shape on the tread surface side and a zigzag shape on the bottom side that are shifted in pitch in the tire width direction, and unevenness that faces each other between the zigzag shapes on the tread surface side and the bottom side.
  • the sipe wall surface is an unevenness when viewed in the tire rotation direction among these unevennesses, between the convex bending point on the tread surface side and the concave bending point on the bottom side, the concave bending point on the tread surface side and the bottom side Between the convex bend points of the tread surface and the convex bend points on the tread surface side, and adjacent convex bend points that are adjacent to each other with ridge lines, and the ridge lines between the ridge lines in order in the tire width direction. It is formed by connecting in a plane.
  • one sipe wall surface has an uneven surface in which convex triangular pyramids and inverted triangular pyramids are arranged alternately in the tire width direction, and the other sipe wall surface alternates between concave triangular pyramids and inverted triangular pyramids.
  • the sipe wall surface has the uneven
  • the sipe wall surface has a structure in which a plurality of prisms having a block shape are connected in the sipe depth direction and the sipe length direction while being inclined with respect to the sipe depth direction.
  • the sipe wall surface has a zigzag shape on the tread surface.
  • the sipe wall surface has a bent portion that is bent in the tire circumferential direction at two or more locations in the tire radial direction inside the block and continues in the tire width direction, and has an amplitude in the tire radial direction at the bent portion. It has a zigzag shape.
  • the sipe wall surface makes the tire circumferential amplitude constant
  • the inclination angle in the tire circumferential direction with respect to the normal direction of the tread surface is made smaller at the sipe bottom side part than the tread surface side part and bent.
  • the amplitude of the tire in the tire radial direction is made larger at the sipe bottom side than at the tread surface side.
  • the pneumatic tire 1 includes a plurality of circumferential main grooves 21 and 22 that extend in the tire circumferential direction, and a plurality of land portions 31 that are partitioned by the circumferential main grooves 21 and 22.
  • At least one row of the center land portions 31 includes a plurality of lug grooves 41 extending in the tire width direction and a plurality of blocks 5 defined by the lug grooves 41 (see FIG. 3).
  • the left and right edge portions on the circumferential main groove 21 side of the block 5 have a step shape having an amplitude in the tire width direction.
  • the front and rear edge portions on the lug groove 41 side of the block 5 have a step shape having an amplitude in the tire circumferential direction.
  • the plurality of blocks 5 each have a plurality of sipes extending in the tire width direction.
  • an 80 [%] sipe 51 formed in one block 5 is a semi-closed sipe that opens into the circumferential main groove 21 at one end and terminates in the block 5 at the other end. is there.
  • the projection length P of the semi-closed sipe 51 in the tire circumferential direction and the width-direction length Wb of the edge portion on the lug groove 41 side of the block 5 have a relationship of 0.30 ⁇ P / Wb ⁇ 0.60. Respectively.
  • the circumferential main groove 21 side of the block 5 and the edge portion of the lug groove 41 have step shapes, so that the edge action of the block 5 is improved and the performance of the tire on ice and snow is improved.
  • the 80% sipe 51 formed in one block 5 is a semi-closed sipe, stress concentration at the edge portion of the block 5 is relaxed while securing the rigidity of the block 5. Thereby, the collapse of the block 5 at the time of tire contact is suppressed, and there is an advantage that the uneven wear resistance performance of the tire (particularly, the center wear resistance performance of the tire mounted on the drive shaft of the vehicle) is improved.
  • the ratio P / Wb between the projection length P of the semi-closed sipe 51 and the width direction length Wb of the block 5 is optimized. That is, by satisfying 0.30 ⁇ P / Wb, the projection length P of the semi-closed sipe 51 is secured, and the stress concentration at the edge portion of the block 5 is moderated appropriately. Further, by satisfying P / Wb ⁇ 0.60, the rigidity of the block 5 is ensured, and the collapse of the block 5 at the time of tire contact is suppressed.
  • the sipe depth Ds1 of the semi-closed sipe 51 and the groove depth GD of the circumferential main groove 21 have a relationship of 0.55 ⁇ Ds1 / GD ⁇ 0.85 (see FIG. 6).
  • the sipe depth Ds1 is optimized. That is, by satisfying 0.55 ⁇ Ds1 / GD, the sipe depth Ds1 is ensured, and the action of the sipe 51 is appropriately obtained. Further, since Ds1 / GD ⁇ 0.85, the rigidity of the block 5 is ensured, and the collapse of the block 5 at the time of tire contact is suppressed.
  • the semi-closed sipe 51 has the bottom upper part 511 in the opening part with respect to the circumferential direction main groove 21 (refer FIG. 6).
  • the sipe depth Ds2 in the bottom upper part 511 and the groove depth GD of the circumferential main groove 21 have a relationship of 0.05 ⁇ Ds2 / GD ⁇ 0.25.
  • the stress concentration at the edge portion on the circumferential main groove 21 side of the block 5 is alleviated, and the collapse of the block 5 at the time of tire contact is suppressed.
  • the sipe depth Ds2 is ensured, and the action of the sipe 51 is appropriately obtained. Further, by satisfying Ds2 / GD ⁇ 0.25, the rigidity of the block 5 is ensured, and the collapse of the block 5 at the time of tire contact is suppressed.
  • the left and right edge portions on the circumferential main groove 21 side of the block 5 have notches 52 in the step-shaped step portions (see FIG. 3). Thereby, the slip amount of the edge part of the block 5 at the time of tire contact is equalized, and there is an advantage that uneven wear of the block 5 is suppressed.
  • the circumferential length Lb of the edge portion on the circumferential main groove 21 side of the block 5 and the position Mc of the notch portion 52 in the edge portion are 0.35 ⁇ Mc / Lb ⁇ .
  • the relationship is 0.65 (see FIG. 3).
  • the notch portion 52 is disposed at the center of the edge portion of the block 5, so that stress concentration at the edge portion of the block 5 is effectively alleviated. Thereby, there exists an advantage by which the partial wear of the block 5 is suppressed effectively.
  • the depth Dc of the notch 52 and the groove depth GD of the circumferential main groove 21 have a relationship of 0.50 ⁇ Dc / GD ⁇ 0.80 (see FIG. 5). ).
  • the depth Dc of the notch part 52 is optimized. That is, by satisfying 0.50 ⁇ Dc / GD, the depth Dc of the notch 52 is ensured, and the action of the notch 52 can be appropriately obtained. Further, since Dc / GD ⁇ 0.80, the rigidity of the block 5 is ensured, and the collapse of the block 5 at the time of tire contact is suppressed.
  • the opening width Wl of the lug groove 41 in the tire circumferential direction and the circumferential length Lb of the edge portion on the circumferential main groove 21 side of the block 5 are 0.08 ⁇ Wl / Lb. ⁇ 0.18 (see FIG. 3).
  • the opening width Wl of the lug groove 41 is optimized. That is, by satisfying 0.08 ⁇ Wl / Lb, the opening width Wl of the lug groove 41 is ensured, and the drainage performance and snow discharge performance of the lug groove 41 are ensured.
  • Wl / Lb ⁇ 0.18 since Wl / Lb ⁇ 0.18, the rigidity of the block 5 in the tire circumferential direction is ensured, and the collapse of the block 5 at the time of tire contact is suppressed.
  • the lug groove 41 has the bottom upper part 411 (refer FIG. 4). Further, the groove depth DL of the lug groove 41 in the bottom upper portion 411 and the groove depth GD of the circumferential main groove 21 have a relationship of 0.50 ⁇ DL / GD ⁇ 0.80. In such a configuration, the lug groove 41 has the bottom upper portion 411, so that the rigidity of the block 5 is ensured and the collapse of the block 5 at the time of tire contact is suppressed. Moreover, there exists an advantage by which ratio DL / GD is optimized.
  • the groove depth DL of the lug groove 41 in the bottom upper portion 411 is ensured, and the drainage performance and snow discharge performance of the lug groove 41 are ensured. Further, since DL / GD ⁇ 0.80, the reinforcing action of the rigidity of the block 5 by the bottom upper portion 411 is appropriately ensured.
  • the step-shaped stepped portion 53 at the edge portion of the block 5 on the lug groove 41 side is 40% or more of the widthwise length Wb of the edge portion of the block 5 on the lug groove 41 side. It is in a position of 60% or less (see FIG. 3).
  • the step-shaped stepped portion 53 is arranged at the center of the edge portion of the block 5, so that stress concentration at the edge portion of the block 5 is effectively alleviated. Thereby, there exists an advantage by which the fall of the block 5 at the time of tire contact is suppressed.
  • the width direction length Wb (see FIG. 3) of the edge portion on the lug groove 41 side of the block 5 and the tire ground contact width TW (see FIG. 2) are 0.10 ⁇ Wb / It has a relationship of TW ⁇ 0.18.
  • the width direction length Wb of the block 5 is optimized. That is, by satisfying 0.10 ⁇ Wb / TW, there is an advantage that the rigidity of the block 5 in the tire width direction is ensured and the collapse of the block 5 at the time of tire contact is suppressed. Further, by satisfying Wb / TW ⁇ 0.18, the groove width of the circumferential main groove 21 can be ensured appropriately, and the drainage and snow drainage of the circumferential main groove 21 can be secured.
  • the circumferential length Lb of the edge portion of the block 5 on the circumferential main groove 21 side and the widthwise length Wb of the edge portion of the block 5 on the lug groove 41 side are 1. 15 ⁇ Lb / Wb ⁇ 1.50 (see FIG. 3).
  • the shape of the block 5 is optimized. That is, by satisfying 1.15 ⁇ Lb / Wb, the circumferential length Lb of the block 5 is ensured, and the collapse of the block 5 at the time of tire contact is suppressed. Further, since Lb / Wb ⁇ 1.50, the rigidity in the width direction of the block 5 is ensured, and uneven wear of the block 5 is suppressed.
  • the semi-closed sipe 51 is a three-dimensional sipe (see FIGS. 7 and 8). Thereby, the meshing force of the sipe 51 is increased, and there is an advantage that the collapse of the block 5 at the time of tire contact is suppressed.
  • the tread rubber 15 has a rubber hardness of 50 or more and 75 or less. Thereby, there exists an advantage by which the rigidity of a tread part is ensured appropriately.
  • the pneumatic tire 1 is applied to a low flat tire having a flat rate of 70 [%] or less, and particularly a small size having a maximum air pressure defined by JATMA within a range of 350 [kPa] to 600 [kPa]. It is preferable to apply truck tires.
  • the ground contact state of the tread portion is likely to change between when the load is loaded and when the load is not loaded. That is, the center area and the shoulder area of the tread portion are uniformly grounded when the load is loaded, but the ground contact area of the shoulder area is reduced when the luggage is not loaded. Then, the land part of a center area
  • 9 and 10 are charts showing the results of the performance test of the pneumatic tire according to the embodiment of the present invention.
  • test tires are mounted on all wheels of a 3-ton truck, which is a test vehicle, and the test vehicle runs on a paved road of 50,000 [km] at an average speed of 60 [km / h]. Uneven wear generated on the block is observed. Based on this observation result, index evaluation is performed with the conventional example 1 as a reference (100). This value is preferably as large as possible, and if it is 110 or more, it can be said that it is particularly superior to the conventional example.
  • the test tires of Examples 1 to 18 have the tread pattern shown in FIG. However, in Examples 1 to 10, the block 5 does not have the notch 52.
  • the shape of the edge portion of the block of the center land portion 31 and the sipe structure are different from the configuration of the first embodiment.
  • the total number of sipes and the sipes density are the same as those in the first embodiment.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Tires In General (AREA)

Abstract

Pneumatique (1) configuré d'une manière telle que les bords gauche et droit de blocs (5), les bords étant tournés vers des rainures principales circonférentielles (21), ont une forme étagée, dont la grandeur, dans le sens de la largeur du pneumatique, varie. Les bords avant et arrière des blocs (5), les bords étant tournés vers des rainures de pavé (41), ont une forme étagée, dont la grandeur, dans la direction circonférentielle du pneumatique, varie. Les blocs (5) ont chacun des lamelles s'étendant dans le sens de la largeur du pneumatique. Quatre-vingts pour cent des lamelles (51) formées dans chacun des blocs (5) sont des lamelles du type semi-fermé, chacune d'elles débouchant au niveau d'une première extrémité sur une rainure principale périphérique (21) et se terminant au niveau de l'autre extrémité dans le bloc (5). De plus, la longueur projetée (P) d'une lame semi-fermée (51) dans la direction circonférentielle du pneumatique et la longueur (Wb), dans le sens de la largeur, d'un bord d'un bloc (5), le bord étant tourné vers une rainure de pavé (41), présentent la relation 0,30 ≤ P/Wb ≤ 0,60.
PCT/JP2015/063063 2014-05-02 2015-05-01 Pneumatique WO2015167007A1 (fr)

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US20210260930A1 (en) * 2018-08-30 2021-08-26 The Yokohama Rubber Co., Ltd. Pneumatic tire
CN115157935A (zh) * 2022-07-20 2022-10-11 中策橡胶集团股份有限公司 一种共振吸声降低噪音的轮胎
CN115157934A (zh) * 2022-07-20 2022-10-11 中策橡胶集团股份有限公司 一种扰乱气流降低噪音的轮胎
US11724549B2 (en) 2018-01-18 2023-08-15 The Yokohama Rubber Co., Ltd. Pneumatic tire

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JP6907777B2 (ja) * 2017-07-19 2021-07-21 住友ゴム工業株式会社 タイヤ
JP7119529B2 (ja) * 2018-04-19 2022-08-17 横浜ゴム株式会社 空気入りタイヤ
JP7178254B2 (ja) * 2018-12-20 2022-11-25 Ｔｏｙｏ Ｔｉｒｅ株式会社 空気入りタイヤ
JP7403987B2 (ja) * 2019-08-07 2023-12-25 Ｔｏｙｏ Ｔｉｒｅ株式会社 空気入りタイヤ
JP7399679B2 (ja) * 2019-10-29 2023-12-18 株式会社ブリヂストン 空気入りタイヤ

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JP2000255216A (ja) * 1999-01-05 2000-09-19 Yokohama Rubber Co Ltd:The 空気入りラジアルタイヤ
JP2001277814A (ja) * 2000-03-30 2001-10-10 Yokohama Rubber Co Ltd:The 冬用空気入りタイヤ
JP2004026158A (ja) * 2003-10-20 2004-01-29 Bridgestone Corp 重荷重用スタッドレス空気入りタイヤ
JP2006056459A (ja) * 2004-08-23 2006-03-02 Sumitomo Rubber Ind Ltd 空気入りタイヤ
WO2007142073A1 (fr) * 2006-05-29 2007-12-13 Bridgestone Corporation Bandage pneumatique
JP2009012671A (ja) * 2007-07-06 2009-01-22 Bridgestone Corp 空気入りタイヤ
JP2013116725A (ja) * 2011-11-04 2013-06-13 Bridgestone Corp 空気入りタイヤ

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EP2436536B1 (fr) * 2009-05-25 2014-09-10 Bridgestone Corporation Bandage pneumatique
JP5956139B2 (ja) * 2011-11-11 2016-07-27 株式会社ブリヂストン 空気入りタイヤ

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JPH07329510A (ja) * 1994-06-09 1995-12-19 Ohtsu Tire & Rubber Co Ltd :The 空気入りタイヤ
JP2000255216A (ja) * 1999-01-05 2000-09-19 Yokohama Rubber Co Ltd:The 空気入りラジアルタイヤ
JP2001277814A (ja) * 2000-03-30 2001-10-10 Yokohama Rubber Co Ltd:The 冬用空気入りタイヤ
JP2004026158A (ja) * 2003-10-20 2004-01-29 Bridgestone Corp 重荷重用スタッドレス空気入りタイヤ
JP2006056459A (ja) * 2004-08-23 2006-03-02 Sumitomo Rubber Ind Ltd 空気入りタイヤ
WO2007142073A1 (fr) * 2006-05-29 2007-12-13 Bridgestone Corporation Bandage pneumatique
JP2009012671A (ja) * 2007-07-06 2009-01-22 Bridgestone Corp 空気入りタイヤ
JP2013116725A (ja) * 2011-11-04 2013-06-13 Bridgestone Corp 空気入りタイヤ

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11724549B2 (en) 2018-01-18 2023-08-15 The Yokohama Rubber Co., Ltd. Pneumatic tire
US20210260930A1 (en) * 2018-08-30 2021-08-26 The Yokohama Rubber Co., Ltd. Pneumatic tire
CN115157935A (zh) * 2022-07-20 2022-10-11 中策橡胶集团股份有限公司 一种共振吸声降低噪音的轮胎
CN115157934A (zh) * 2022-07-20 2022-10-11 中策橡胶集团股份有限公司 一种扰乱气流降低噪音的轮胎

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CN106457922A (zh) 2017-02-22

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