WO2020090884A1 - Bande de roulement de pneu pour performances sur la neige améliorées - Google Patents

Bande de roulement de pneu pour performances sur la neige améliorées Download PDF

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Publication number
WO2020090884A1
WO2020090884A1 PCT/JP2019/042570 JP2019042570W WO2020090884A1 WO 2020090884 A1 WO2020090884 A1 WO 2020090884A1 JP 2019042570 W JP2019042570 W JP 2019042570W WO 2020090884 A1 WO2020090884 A1 WO 2020090884A1
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WO
WIPO (PCT)
Prior art keywords
contact element
tread
projection portion
chamfered portion
material constituting
Prior art date
Application number
PCT/JP2019/042570
Other languages
English (en)
Inventor
Tomotake UCHIDA
Shuichi Kaneko
Original Assignee
Compagnie Generale Des Etablissements Michelin
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Filing date
Publication date
Application filed by Compagnie Generale Des Etablissements Michelin filed Critical Compagnie Generale Des Etablissements Michelin
Publication of WO2020090884A1 publication Critical patent/WO2020090884A1/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
    • B60C11/11—Tread patterns in which the raised area of the pattern consists only of isolated elements, e.g. blocks
    • 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
    • B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
    • B60C11/1376—Three dimensional block surfaces departing from the enveloping tread contour
    • 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
    • B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
    • B60C11/1376—Three dimensional block surfaces departing from the enveloping tread contour
    • B60C11/1392—Three dimensional block surfaces departing from the enveloping tread contour with chamfered block edges
    • 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
    • B60C11/0008—Tyre tread bands; Tread patterns; Anti-skid inserts characterised by the tread rubber
    • B60C2011/0016—Physical properties or dimensions
    • 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
    • B60C2011/0337—Tread patterns characterised by particular design features of the pattern
    • B60C2011/0339—Grooves
    • B60C2011/0358—Lateral grooves, i.e. having an angle of 45 to 90 degees to the equatorial plane
    • 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
    • B60C11/1204—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe
    • B60C2011/1209—Tread patterns characterised by the use of narrow slits or incisions, e.g. sipes with special shape of the sipe straight at the tread surface

Definitions

  • the present invention relates to a tread for a tire, in particular to a tread for a tire for improving snow performance while maintaining wet performance.
  • JP2017-105411 discloses a pneumatic tire having a tread consists of a projection portion projecting radially for improving tire noise.
  • JP2011-140254 discloses also a pneumatic tire having a tread consists of a projection portion projecting radially with a chamfered portion on a face opposite to a closest edge for improving tire noise.
  • JP2011-140253 discloses also a pneumatic tire having a tread consists of a projection portion projecting radially with a chamfered portion on a face opposite to a closest edge for improving tire noise.
  • JP2011-031831 discloses a pneumatic tire having a tread with predetermined rotational direction consists of a projection portion projecting radially for irregular wear improvement while maintaining traction performance on wet and wintry surface.
  • JP2007-022242 discloses a pneumatic tire having a tread with predetermined rotational direction consists of a plurality of fine ribs (projection portion) each having a triangular cross sectional shape being arranged as a saw blade for better traction performance on wintry surface.
  • JP2002-046424 discloses a pneumatic tire having a concave shaped block for improving performance on ice covered road surface.
  • a “radial direction/orientation” is a direction/orientation perpendicular to axis of rotation of the tire. This direction/orientation corresponds to thickness orientation of the tread.
  • An “axial direction/orientation” is a direction/orientation parallel to axis of rotation of the tire.
  • a “circumferential direction/orientation” is a direction/orientation which is tangential to any circle centered on axis of rotation. This direction/orientation is perpendicular to both the axial direction/orientation and the radial direction/orientation.
  • a “tire” means all types of elastic tire whether or not subjected to an internal pressure.
  • a “tread” of a tire means a quantity of rubber material bounded by lateral surfaces and by two main surfaces one of which is intended to come into contact with ground when the tire is rolling.
  • a “groove” is a space between two rubber faces/sidewalls which do not contact between themselves under usual rolling condition connected by another rubber face/ bottom.
  • a groove has a width and a depth.
  • An “incision”, also referred to as a “sipe”, is a narrow cutout formed toward radially inwardly from a surface of a tread made by, for example a thin blade having a shape like a knife blade.
  • a width of the incision at the surface of the tread is narrower than a groove, for example less than or equal to 2.0mm. This incision may, different from the groove, be partly or completely closed when such the incision is in a contact patch and under usual rolling condition.
  • a “contact patch” is a footprint of a tire mounted onto its standard rim as identified in tire standards such as ETRTO, JATMA or TRA, and inflated at its nominal pressure and under its nominal load.
  • the present invention provides a tread for a tire having a contact face intended to come into contact with ground during rolling, the tread being provided with a plurality of groove of a depth D and/or a plurality of incision of a depth d extending generally in axial orientation of the tire and being disposed such that at least two grooves or two incisions or one groove and one incision being always located within a contact patch, the plurality of groove and/or the plurality of incision delimitating a plurality of contact element, the plurality of contact element having a top face constituting a part of the contact face and a frontal face facing to the groove or to the incision, the top face and the frontal face creating an edge at an intersection between the top face and the frontal face, at least one of the plurality of contact element being provided with at least one projection portion projecting radially outwardly from the top face with a radial height h in a region between the closest edge and 40% of a circumferential length of the contact element from the closest edge, the projection portion being
  • This arrangement provides higher performance on wintry surface and on non-wintry surface at the same time.
  • the contact element is provided with at least one projection portion projecting radially outwardly from the top face with a radial height h, such the projection portion is able to generate high pressure to scrape snow, performance on wintry surface especially snow performance can be improved.
  • the projection portion is provided with a chamfered portion on a side facing to the closest edge and the chamfered portion has an angle A relative to the top face on cross sectional view along with circumferential orientation, such the chamfered portion is able to prevent generating too high pressure and avoid curling of the projection portion, performance on non-wintry surface can be improved at the same time.
  • the projection portion is provided outside of the region between the closest edge and 40% of a circumferential length of the contact element from the closest edge, there is a risk that performance on wintry surface would be degraded as the projection portion cannot generate high contact pressure efficiently.
  • the projection portion can generate high contact pressure efficiently.
  • the chamfered portion is provided on a side opposite to the closest edge, the chamfered portion would be less effective to prevent generating too high pressure and difficult to prevent curling of the projection portion, performance on non-wintry surface cannot be improved even performance on wintry surface may be improved.
  • the chamfered portion By placing the chamfered portion on the side facing to the closest edge, it is possible to improve performance on wintry surface and on non-wintry surface at the same time.
  • the projection portion is composed of a material different than a material constituting the contact element at least in a portion radially including the chamfered portion, and the material constituting the portion radially including the chamfered portion has a glass transition temperature Tg higher than a glass transition temperature Tg of the material constituting the contact element, the chamfered portion would help to reduce an edge pressure during braking on non-wintry surface especially on wet surface, thus performance on non-wintry surface can further be improved while maintaining a benefit to have such the projection portion provided with the chamfered portion for performance on wintry surface.
  • the glass transition temperature Tg of the material constituting the portion radially including the chamfered portion is at least equal to 10 °C higher than the glass transition temperature Tg of the material constituting the contact element.
  • this difference between the glass transition temperature Tg of the material constituting the portion radially including the chamfered portion and the glass transition temperature Tg of the material constituting the contact element is less than 10 °C, there is a risk that performance improvement on non-wintry surface especially on wet surface becomes insufficient due to insufficient edge pressure reduction during braking on non-wintry surface especially on wet surface.
  • the glass transition temperature Tg of the material constituting the portion radially including the chamfered portion is at least equal to 10 °C higher than the glass transition temperature Tg of the material constituting the contact element, it is possible to improve performance on non-wintry surface especially on wet surface.
  • This difference between the glass transition temperature Tg of the material constituting the portion radially including the chamfered portion and the glass transition temperature Tg of the material constituting the contact element is preferably at least equal to 12 °C, more preferably at least equal to 15 °C.
  • the portion radially including the chamfered portion is extending radially into the contact element inwardly.
  • the portion radially including the chamfered portion occupies whole volume of the projection portion.
  • the chamfered portion is provided in a whole width of the projection portion.
  • the radial height h of the projection portion is at most equal to 20% of the depth D of the groove or the depth d of the incision whichever is deeper.
  • this radial height h of the projection portion is more than 20% of the depth D of the groove or the depth d of the incision whichever is deeper, there is a risk that the projection portion would buckle easily which makes difficult to scrape snow thus performance on wintry surface would be degraded.
  • this height h of the projection portion is set at most equal to 20% of the depth D of the groove or the depth d of the incision whichever is deeper, it is possible to improve effectively performance on wintry surface.
  • This height h of the projection portion relative to the depth D of the groove or the depth d of the incision whichever is deeper is preferably at most equal to 15% and at least equal to 0.3 mm, more preferably at most equal to 15% and at least equal to 0.5 mm.
  • the angle A of the chamfered portion is from 30 to 60 degrees.
  • angle A of the chamfered portion is less than 30 degrees, there is a risk that the chamfered portion would be less effective to prevent generating too high pressure thus performance on non-wintry surface would be degraded. If the angle A of the chamfered portion is more than 60 degrees, there is a risk that the chamfered portion would be less effective to prevent curling of the projection portion, thus performance on non-wintry surface would be degraded also. By setting this angle A of the chamfered portion is from 30 to 60 degrees, it is possible to effectively improve performance on non-wintry surface.
  • the projection portion is flush with the frontal face of the contact element at least partly.
  • the projection portion is offset from the closest edge.
  • Fig. 1 is a schematic plan view of a tread according to a first embodiment of the present invention
  • Fig. 2 is a cross sectional view taken along line II-II in Fig. 1
  • Fig. 3 is an enlarged schematic view showing a portion indicated as III in Fig. 2
  • Fig. 4 is a schematic cross sectional view of a tread according to a second embodiment of the present invention
  • Fig. 5 is a cross sectional view of a tread according to prior art.
  • a tread 1 for a tire according to a first embodiment of the present invention will be described referring to Figs. 1, 2 and 3.
  • Fig. 1 is a schematic plan view of the tread according to a first embodiment of the present invention.
  • Fig. 2 is a cross sectional view taken along line II-II in Fig. 1.
  • Fig. 3 is an enlarged schematic view showing a portion indicated as III in Fig. 2.
  • the tread 1 is a tread for a tire having a contact face 2 intended to come into contact with ground during rolling, and a plurality of groove 3 of a depth D (shown in Fig. 2) opening to the contact face 2.
  • the plurality of groove 3 includes a lateral groove 3a extending generally in axial orientation as indicated by line YY’ and a circumferential groove 3b extending generally in circumferential orientation as indicated by line XX’.
  • the plurality of groove 3 (the lateral groove 3a and the circumferential groove 3b) is delimiting a plurality of contact element 5, and the circumferential groove 3b is dividing the tread 1 axially into three block rows, two shoulder block rows located axially outward and one center block row.
  • Each the plurality of contact element 5 is provided with a plurality of incision 4 of a depth d (shown in Fig. 2) extending generally in the axial orientation.
  • the plurality of incision 4 is opening to the circumferential groove 3b at two axial ends.
  • Each the plurality of contact element 5 having a top face 51 constituting a part of the contact face 2 and a frontal face 52 facing to the groove 3 (the lateral groove 3a).
  • the top face 51 and the frontal face 52 creating an edge 53 at an intersection between the top face 51 and the frontal face 52.
  • each the plurality of contact element 5 being provided with two projection portions 6 projecting radially outwardly from the top face 51 with a radial height h in a region between the closest edge 53 and 40% of a circumferential length of the contact element 5 from the closest edge 53 (shown in Fig. 2).
  • Each the projection portion 6 is provided with a chamfered portion 61 in a whole width of the projection portion 6 on a side facing to the closest edge 53 and having an angle A relative to the top face 51 (shown in Figs. 2 and 3), and with a flat portion 62 parallel to the top face 51 (shown in Figs. 2 and 3).
  • the projection portion 6 on one center block row is offset from the closest edge 53. Contrary the projection portion 6 on two shoulder block rows is not offset from the closest edge 53.
  • the projection portion 6 in two shoulder block rows of the tread 1 has a width narrower than a width of the contact element 5, and the projection portion 6 in one center block row of the tread 1 has a width equal to a width of the contact element 5.
  • the contact element 5 in one center block row of the tread 1 delimited by the groove 3 (the lateral groove 3a) of the depth D is also provided with one incision 4 of the depth d at around circumferentially a center of the contact element 5, and the depth d of the incision 4 is identical to the depth D of the groove 3 (the lateral groove 3a).
  • the depth D of the groove 3 (the lateral groove 3a) and the depth d of the incision 4 are both 9.2 mm.
  • the contact element 5 in one center block row of the tread 1 is provided with the projection portion 6 projecting radially outwardly from the top face 51 which is constituting a part of the contact face 2 with a radial height h in the region between the closest edge 53 and 40% of the circumferential length of the contact element 5 from the closest edge 53.
  • the projection portion 6 is offset from the closest edge 53.
  • the radial height h of the projection portion 6 is at most equal to 20% of the depth D of the groove 3 or the depth d of the incision 4 whichever is deeper. In this first embodiment, the height h of the projection portion 6 is 1.0 mm.
  • the projection portion 6 is provided with the chamfered portion 61 on the side facing to the closest edge 53.
  • the projection portion 6 has the angle A relative to the top face 51 and this angle A is from 30 to 60 degrees.
  • the projection portion 6 further comprises the flat portion 62 parallel to the top face 51. In this first embodiment, the angle A of the chamfered portion 61 relative to the top face 51 is 40 degrees.
  • the projection portion 6 is composed of a material different than a material constituting the contact element 5 at least in a portion 63 radially including the chamfered portion 61.
  • the material constituting the portion 63 radially including the chamfered portion 61 has a glass transition temperature Tg higher than a glass transition temperature Tg of the material constituting the contact element 5.
  • the portion 63 radially including the chamfered portion 61 occupies whole volume of the projection portion 6.
  • the glass transition temperature Tg of the material constituting the portion 63 radially including the chamfered portion 61 is at least equal to 10 °C higher than the glass transition temperature Tg of the material constituting the contact element 5.
  • the glass transition temperature Tg of the material constituting the portion 63 radially including the chamfered portion 61 is -10 °C
  • the glass transition temperature of the material constituting the contact element 5 is -25 °C
  • the glass transition temperature Tg of the material constituting the portion 63 radially including the chamfered portion 61 is 15 °C higher than the glass transition temperature Tg of the material constituting the contact element 5.
  • the contact element 5 is provided with at least one projection portion 6 projecting radially outwardly from the top face 51 with a radial height h, such the projection portion 6 is able to generate high pressure to scrape snow, performance on wintry surface especially snow performance can be improved.
  • the projection portion 6 is provided with a chamfered portion 61 on a side facing to the closest edge 53 and the chamfered portion 61 has an angle A relative to the top face 51 on cross sectional view along with circumferential orientation, such the chamfered portion 61 is able to prevent generating too high pressure and avoid curling of the projection portion 6, performance on non-wintry surface can be improved at the same time.
  • the projection portion 6 is provided outside of the region between the closest edge 53 and 40% of a circumferential length of the contact element 5 from the closest edge 53, there is a risk that performance on wintry surface would be degraded as the projection portion 6 cannot generate high contact pressure efficiently.
  • the projection portion 6 can generate high contact pressure efficiently.
  • the chamfered portion 61 is provided on a side opposite to the closest edge 53, the chamfered portion 61 would be less effective to prevent generating too high pressure and difficult to prevent curling of the projection portion 6, performance on non-wintry surface cannot be improved even performance on wintry surface may be improved.
  • the chamfered portion 61 By placing the chamfered portion 61 on the side facing to the closest edge 53, it is possible to improve performance on wintry surface and on non-wintry surface at the same time.
  • the projection portion 6 is composed of a material different than a material constituting the contact element 5 at least in the portion 63 radially including the chamfered portion 61, and the material constituting the portion 63 radially including the chamfered portion 61 has a glass transition temperature Tg higher than a glass transition temperature Tg of the material constituting the contact element 5, the chamfered portion 61 would help to reduce an edge pressure during braking on non-wintry surface especially on wet surface, thus performance on non-wintry surface can further be improved while maintaining a benefit to have such the projection portion 6 provided with the chamfered portion 61 for performance on wintry surface.
  • the glass transition temperature Tg of the material constituting the portion 63 radially including the chamfered portion 61 is at least equal to 10 °C higher than the glass transition temperature Tg of the material constituting the contact element 5, it is possible to improve performance on non-wintry surface especially on wet surface.
  • This difference between the glass transition temperature Tg of the material constituting the portion 63 radially including the chamfered portion 61 and the glass transition temperature Tg of the material constituting the contact element 5 is preferably at least equal to 12 °C, more preferably at least equal to 15 °C.
  • portion 63 radially including the chamfered portion 61 occupies whole volume of the projection portion 6, it is possible to improve productivity of the tread.
  • the chamfered portion 61 is provided in a whole width of the projection portion 6, performance on both wintry surface and non-wintry surface can further be improved as it is possible to increase effectiveness of the projection portion 6 provided with the chamfered portion 61.
  • the radial height h of the projection portion 6 is at most equal to 20% of the depth D of the groove 3 or the depth d of the incision 4 whichever is deeper, it is possible to improve effectively performance on wintry surface.
  • this radial height h of the projection portion 6 is more than 20% of the depth D of the groove 3 or the depth d of the incision 4 whichever is deeper, there is a risk that the projection portion 6 would buckle easily which makes difficult to scrape snow thus performance on wintry surface would be degraded.
  • This height h of the projection portion 6 relative to the depth D of the groove 3 or the depth d of the incision 4 whichever is deeper is preferably at most equal to 15% and at least equal to 0.3 mm, more preferably at most equal to 15% and at least equal to 0.5 mm.
  • angle A of the chamfered portion 61 is from 30 to 60 degrees, it is possible to effectively improve performance on non-wintry surface.
  • angle A of the chamfered portion 61 is less than 30 degrees, there is a risk that the chamfered portion 61 would be less effective to prevent generating too high pressure thus performance on non-wintry surface would be degraded. If the angle A of the chamfered portion 61 is more than 60 degrees, there is a risk that the chamfered portion 61 would be less effective to prevent curling of the projection portion 6, thus performance on non-wintry surface would be degraded also.
  • the projection portion 6 is offset from the closest edge 53, balance between performance on wintry surface and on non-wintry surface would be improved as it is possible to increase a degree of freedom for placing the projection portion 6.
  • the projection portion 6 may be provided in a various kind of form, for example curved, waved or combination of these forms with straight form. Multiple projection portions 6 may be provided relative to the one edge 53. In such the case, each the projection portion 6 may have the same form, or may have different form one another including its position relative to the edge 53, the height h of the projection portion 6 and/or the angle A of the chamfered portion 61 relative to the top face 51.
  • Only one projection portion 6 may be provided to one single contact element 5, or in case several projection portions 6 is provide to one single contact element 5, each the projection portion 6 may have the same form, or may have different form one another including its position relative to the edge 53, the height h of the projection portion 6 and/or the angle A of the chamfered portion 61 relative to the top face 51. Additional projection portion 6 may be provided to an edge made by the incision 4.
  • the chamfered portion 61 may extend to below the edge 53 as to include partly the contact element 5. Or the edge 53 of the contact element 5 may be chamfered also.
  • Fig. 4 is a schematic cross sectional view of a tread according to a second embodiment of the present invention.
  • the construction of this second embodiment is similar to that of the first embodiment other than the arrangement shown in Fig. 4, thus description will be made referring to Fig. 4.
  • a contact element 25 of the tread 21 delimited by a groove 23 (a lateral groove 23a) is provided with an incision 24 at around a center of the contact element 25, and a projection portion 26 is provided only to a middle portion of the contact element 25.
  • the projection portion 26 is provided with the chamfered portion 261 facing to the closest edge 253 having a flat portion 262 parallel to the top face 251.
  • the chamfered portion 261 is composed of a material different than a material constituting the contact element 25 at least in a portion 263 radially including the chamfered portion 261.
  • a portion including the flat portion 262 is composed of the material same as the material constituting the contact element 25.
  • the material constituting the portion 263 including the chamfered portion 261 has a glass transition temperature Tg higher than a glass transition temperature Tg of the material constituting the contact element 25.
  • the portion 263 including the chamfered portion 261 is extending radially into the contact element 25 inwardly as to occupy a whole surface of a frontal face 252 of the contact element 25 facing to the groove 23.
  • the projection portion 26 is flush with the frontal face 252 of the contact element 25 at least partly.
  • portion 263 radially including the chamfered portion 261 is extending radially into the contact element 25 inwardly, it is possible to improve productivity of the tread 21.
  • the projection portion 26 is flush with the frontal face 252 of the contact element 25 at least partly, performance on wintry surface would further be improved as it is possible to place the projection portion 26 where the projection portion 26 generates high contact pressure efficiently.
  • the projection portion 26 may be provided on the other portion divided by the incision 24, and not only to one single portion but also to several portions.
  • Fig. 5 is a cross sectional view of a tread according to prior art.
  • a tread 101 being provided with a plurality of groove 103 of a depth D delimitating a plurality of contact element 105 having a top face 1051 constituting partly a contact face 102 of the tread 101.
  • the contact element 105 is provided with on incision 104 of a depth d at around a center of the contact element 105.
  • the top face 1051 and a frontal face 1052 creating an edge 1053, a projection portion 106 of a height h being provided as to be flush with the frontal face 1052 of the contact element 105.
  • a top of the projection portion 106 is parallel to the top face 1051.
  • the projection portion 106 is also provided with a chamfered portion 1061.
  • the projection portion 106 is made of a material totally the same as the material constituting the contact element 105.
  • the Example was a tire as described in the above the second embodiment having the height h of the projection portion equals to 1.0 mm, the angle A equals to 45 degrees, the depth D equals to 6.1 mm, a distance between two frontal faces in circumferential orientation equals to 20 mm and with one incision provided, the glass transition temperature Tg of the material constituting the portion radially including the chamfered portion was -10 °C, the glass transition temperature of the material constituting the contact element was -25 °C.
  • the Comparative Example was a tire as described in the above prior art.
  • the Reference was a tire without the projection portion. All the Example, Comparative Example and Reference were made using the same internal construction as a typical radial pneumatic tire, the same material except at the portion radially including the chamfered portion for the Example.
  • results are shown in table.
  • results are represented by an index of 100 for Reference, higher the number indicates better the performance.
  • Unused test tire was mounted onto a trailer. In accordance with ISO 23671, on a straight path 1mm deep wet surface, braking force was applied to the test tire at a speed of 65km/h and peak ⁇ level was calculated.
  • results are also shown in table.
  • results are represented by an index of 100 for Reference, higher the number indicates better the performance.
  • the Example shows improvement on non-wintry surface while still improving performance on wintry surface.

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

Abstract

La présente invention concerne une bande de roulement, laquelle bande comporte une pluralité de rainures et/ou une pluralité d'incisions délimitant une pluralité d'éléments de contact, la pluralité d'éléments de contact ayant une face supérieure et une face frontale créant un bord à une intersection, au moins un élément de la pluralité d'éléments de contact comportant au moins une partie de saillie faisant saillie radialement vers l'extérieur à partir de la face supérieure, la partie de saillie comportant une partie chanfreinée sur un côté dirigé vers le bord le plus proche, la partie chanfreinée ayant un angle A, la partie de saillie est constituée d'un matériau différent d'un matériau constituant l'élément de contact au moins dans une partie comprenant radialement la partie chanfreinée, et le matériau constituant la partie comprenant radialement la partie chanfreinée a une température de transition vitreuse supérieure à une température de transition vitreuse du matériau constituant l'élément de contact.
PCT/JP2019/042570 2018-10-30 2019-10-30 Bande de roulement de pneu pour performances sur la neige améliorées WO2020090884A1 (fr)

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JP2018-203930 2018-10-30
JP2018203930 2018-10-30

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116601017A (zh) * 2020-12-22 2023-08-15 米其林集团总公司 一种轮胎胎面

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JP2002046424A (ja) 2000-08-02 2002-02-12 Bridgestone Corp 空気入りタイヤ
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