WO2013001653A1 - 空気入りタイヤ用トレッド - Google Patents
空気入りタイヤ用トレッド Download PDFInfo
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- WO2013001653A1 WO2013001653A1 PCT/JP2011/065117 JP2011065117W WO2013001653A1 WO 2013001653 A1 WO2013001653 A1 WO 2013001653A1 JP 2011065117 W JP2011065117 W JP 2011065117W WO 2013001653 A1 WO2013001653 A1 WO 2013001653A1
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- WIPO (PCT)
- Prior art keywords
- tread
- rubber composition
- phr
- pneumatic tire
- main groove
- Prior art date
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Classifications
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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
- B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
- B60C11/1353—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove bottom
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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
- B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
- B60C1/0016—Compositions of the tread
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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
- B60C11/04—Tread patterns in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag
- B60C11/042—Tread patterns in which the raised area of the pattern consists only of continuous circumferential ribs, e.g. zig-zag further characterised by the groove cross-section
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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
- B60C11/13—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping
- B60C11/1353—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove bottom
- B60C2011/1361—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove bottom with protrusions extending from the groove bottom
Definitions
- the present invention relates to a tread for a pneumatic tire, and more specifically, a flexible fence is formed in the main groove of the tread to reduce air column resonance noise and maintain drainage performance, and the flexible fence and the tread portion are worn to the same extent.
- the present invention relates to a tread for a pneumatic tire, and a pneumatic tire having such a tread.
- the air column resonance sound of the main groove formed in the tread of the tire is generated by resonance in the pipe (air column) formed by the main groove and the road surface, and the resonance frequency is formed between the road surface and the road surface. Depends on the length of the main air column.
- This air column resonance appears in the form of noise inside and outside the vehicle, and often has a peak around 1 kHz that easily reaches the human ear.
- a so-called flexible fence that is, a projection, extends from the groove wall and bottom of the main groove and blocks all or most of the main groove to form the main groove.
- the flow of water that has entered the main groove is also blocked. Since the drainage of water intervening with the road surface is reduced, the steering stability on a wet road surface is reduced.
- FIG. 4 of Patent Document 1 three groove fences 3 (flexible fences) respectively extending from the opposite groove walls and the groove bottom in the groove are arranged in the main groove with a gap between each other. There is disclosed a technique that achieves both reduction of resonance noise and drainage.
- the partition wall 30 (flexible fence) extending from the groove bottom in the main groove is arranged so that most of the main groove opening is not in contact with the groove wall.
- the thickness of the flexible fence in the tire circumferential direction is thin and easily deformed in order to make the flexible fence function. Therefore, depending on the material used, when traveling, the flexible fence that is easily deformed is less likely to be worn than the tread portion, and there is a difference in the amount of wear between the flexible fence and the tread portion. Due to the difference in the amount of wear, the flexible fence protrudes from the surface of the tread portion (the surface of the tread that forms the tread surface), and from the tread surface during traveling. There is a problem that the flexible fence hits the road surface and noise is generated. The generation of such abnormal noise is contrary to the original role of the flexible fence described above, which is to reduce noise by reducing air column resonance. Further, there is a problem that the flexible fence is worn or damaged at an early stage due to an unintended portion of the flexible fence contacting the road surface due to the protrusion from the tread portion of the flexible fence.
- An object of the present invention is to provide a tread for a pneumatic tire that can suppress a reduction in the effect of reducing air column resonance noise caused by the above, and a pneumatic tire having the tread.
- the present invention provides a tread for a pneumatic tire formed of a rubber composition that comes into contact with a road surface when the tire rolls, and has a bottom surface and two opposing wall surfaces and is deep.
- a tread portion formed with at least one main groove having a thickness D and a width W, and a plurality of flexible fences having a thickness E and blocking at least 70% of a cross-sectional area of the main groove.
- a plurality of flexible fences extending in the groove and arranged at intervals so as to exist in the main groove in the tread surface when the tire rolls, and the plurality of flexible fences are at least It is formed of a rubber composition for a fence different from the rubber composition of the tread part, and the rubber composition for a fence of a flexible fence is more than twice the wear index of the rubber composition of the tread part.
- the rubber composition for a fence has an abrasion index of 50% selected from the group consisting of (a) a diene elastomer, (b) carbon black, an inorganic filler, an organic filler, and a mixture of these fillers.
- a plasticizing system selected from the group consisting of liquid plasticizers, hydrocarbon resins and mixtures thereof, and (d) a filling composition based on a vulcanization system. It is characterized by.
- the present invention is formed in the main groove, blocks at least 70% of the cross-sectional area of the main groove, and exists at least one in the main groove in the tread surface when the tire rolls.
- the length of the air column in the main groove formed with the road surface is changed with a flexible fence arranged at a certain interval, compared with the case where the flexible fence is not formed, and the peak of the air column resonance sound is changed by humans. It is easy to remove the frequency band that can easily reach the ear, and as a result, noise caused by air column resonance is improved.
- the fence rubber composition contains a reinforcing filler in an amount less than 50 phr, which is less than usual and exhibits a higher wear index than the rubber composition forming the tread portion.
- the flexible fence can be worn as much as the tread portion.
- the reinforcing filler among the components constituting the rubber composition forming the tread portion at the same time is relatively high relative to that of the fence rubber composition, typically 70 phr. .
- a filler having a reinforcing property to a rubber composition used for manufacturing a normal tire tread for example, an organic filler such as carbon black, a reinforcement such as silica, and the like.
- Inorganic fillers or mixtures of such fillers, in particular fillers mixed with carbon black and silica, can be used.
- the amount of the reinforcing filler contained in the rubber composition for a fence is less than 40 phr, more preferably less than 20 phr, still more preferably 10 phr or less.
- Suitable carbon blacks are all carbon blacks, especially HAF, ISAF or SAF type blacks ("tire grade" blacks) commonly used in tire treads.
- HAF high-density polyethylene
- SAF SAF type blacks
- the following may be mentioned in more detail: for example, blacks such as N115, N134, N234, N326, N330, N339, N347 and N375, 100, 200 or These are 300 series reinforcing carbon blacks (ASTM class).
- the carbon black may already be incorporated into the isoprene elastomer, for example in the form of a masterbatch (see eg WO 97/36724 or WO 99/16600).
- organic fillers other than carbon black include functionalized polyvinyl aromatic organic fillers as described in International Publication Nos.
- WO 2006/069792 and WO 2006/069793 “Reinforcing inorganic filler” by definition is referred to in this application as “white filler”, “light filler” or even “non-black filler” by definition, as opposed to carbon black,
- a rubber composition intended for tire manufacture can be reinforced without means other than intermediate coupling agents, in other words, its color and its origin (natural nature) which can be replaced with normal tire grade carbon black and its reinforcing function. It should be understood to mean any inorganic or mineral filler, whether or not synthetic).
- Such fillers are generally characterized by the presence of hydroxyl (—OH) groups on their surface, as is known.
- the reinforcing inorganic filler can be in any physical state, ie powder, microspheres, granules, beads or any other suitable dense form.
- the reinforcing inorganic filler includes various reinforcing inorganic fillers, particularly mixtures of highly dispersible siliceous and / or alumina fillers as described below.
- Suitable reinforcing inorganic fillers are in particular siliceous type mineral fillers, in particular silica (SiO2), or aluminous type mineral fillers, in particular alumina (Al2O3).
- the silica used is any reinforcing silica known to those skilled in the art, in particular any precipitated or calcined silica, both having a BET surface area and a CTAB specific surface area of less than 450 m2 / g, preferably in the range of 30 to 400 m2 / g. obtain.
- Examples of highly dispersible precipitated silica (“HDS”) include the following.
- Silicas from Degussa Ultrasil 7000 and Ultrasil 7005 Silicas from Rhodia Zeosil 1165MP, 1135MP and 1115MP; Silica Hi-Sil EZ150G from PPG; Silos from Huber Zeopol 8715, 8745 or 8755; or Silicas having a high specific surface area as described in WO 03/16837.
- the reinforcing filler is a nanoparticle having an average particle size (weight average) of 500 nm, particularly when it is silica or carbon black. More preferably, the average particle size (weight average) of the nanoparticles is between 20 nm and 200 nm, more preferably between 20 nm and 150 nm.
- the average particle size of the nanoparticles indicated by d W (weight average), after dispersion by ultrasonic deagglomeration of the filler to be analyzed in water or surfactant-containing aqueous solution is measured as usual.
- the measurement is carried out according to the following operating method using an XDC (X-ray disc centrifuge) X-ray centrifugal sedimentation rate meter sold by Brookhaven Instruments. That is, a suspension consisting of 3.2 g of an inorganic filler test specimen to be analyzed in 40 ml of water, 60% of a 1500 W ultrasonic probe (1.91 cm (3/4 inch) Vibracell sonicator sold by Bioblock) Prepare by operating for 8 minutes at power (ie 60% away from maximum “power control” position). After sonication, 15 ml of suspension is introduced into the rotating disk.
- XDC X-ray disc centrifuge
- X-ray centrifugal sedimentation rate meter sold by Brookhaven Instruments. That is, a suspension consisting of 3.2 g of an inorganic filler test specimen to be analyzed in 40 ml of water, 60% of a 1500 W ultrasonic probe (1.91 cm (3/4 inch) Vibracell sonicator sold by Bioblock) Prepare by operating for
- a density gradient consisting of 15 ml water (containing 0.05% nonionic surfactant) and 1 ml ethanol is injected into a sedimentation velocimeter disk rotating at 8000 rpm to form a “step gradient”
- 0.3 ml of carbon black suspension is injected onto the gradient surface.
- the mass distribution and weight average particle size d W of the particle size is calculated by sedimentometer software as described above.
- the flexible fence when the flexible fence is in direct contact with the road surface while passing through the tread surface during rolling of the tire, the ground force is contacted between the road surface and the flexible fence due to the reaction force received when the tip of the flexible fence contacts the road surface. causes pressure and slip.
- the wear index of the rubber composition for the fence is larger than the wear index of the rubber composition of the tread portion, even if the ground pressure and the slip amount are reduced due to the deformation of the flexible fence, it is effective.
- the flexible fence can be worn to the same extent as the wear amount of the tread portion.
- the rubber composition in the tread portion contains the above-described reinforcing filler at 60 phr or more, more preferably between 60 phr and 140 phr.
- the wear index of the rubber composition for a fence is smaller than twice the wear index of the rubber composition of the tread part, the wear will occur when the ground pressure and slip generated when the flexible fence contacts the road surface are small. This makes it difficult to wear the flexible fence as much as the tread portion.
- This wear index more than twice this is the tread for pneumatic tires that the present inventors wear to the same extent as the tread portion of the flexible fence while reducing the air column resonance noise and maintaining the drainage performance. Is the numerical value found as appropriate in the process of evaluating such actions (especially drainage performance, flexible fence wear performance), and if the numerical value is within the above range (twice or more), It has been found by analysis and experiment that the above action can be obtained effectively.
- the “groove” is a width and depth formed by connecting two opposing surfaces (wall surfaces) that do not come into contact with each other under normal use conditions by other surfaces (bottom surfaces). A space that has
- main groove refers to a groove having a relatively wide width among various grooves formed in the tread, which mainly handles fluid drainage.
- the main groove means a groove extending in the tire circumferential direction in a straight line, zigzag shape or wave shape in many cases, but has a relatively wide width mainly extending the drainage of the fluid extending at an angle with respect to the tire rotation direction. Grooves with are also included.
- Thread surface refers to the surface area of the tread that comes into contact with the road surface when the tire is mounted on the applicable rim specified by the following industrial standards, filled with the rated internal pressure, and loaded with the rated load. Say.
- the “standard” is defined by an industrial standard effective in the region where the tire is produced or used.
- the industrial standard is “STANDARDS MANUAL” of ETRTO (The European Tyre and Rim Technical Organization) in Europe, and TRA (THE TIRE AND RIMCASSOCIATION IN.
- the tire association (JATMA) "JATMA YEAR BOOK”.
- “applicable rim” refers to a rim defined in these standards depending on the tire size
- “rated internal pressure” refers to an air pressure defined in accordance with the load capacity in these standards.
- “Rated load” refers to the maximum mass allowed to be applied to a tire in these standards.
- the “wearability of the rubber composition” refers to the wear volume of the rubber composition obtained in the Akron wear test measured according to JIS K6264-1 and JIS K6264-2.
- the wear volume of the rubber composition is determined from the difference in mass before and after the main test operation of the vulcanized rubber test piece using an Akron abrasion tester based on the above-mentioned standard.
- the number of revolutions of the grinding wheel is 500 for the preliminary operation and 3000 for the main test, and a tilt angle of 15 degrees is given between the test piece and the grinding wheel.
- the specimen is pressed against the grinding wheel with an applied force of 27.0 N, and the rotational speed of the specimen is 100 revolutions per minute.
- the “wear index” is an index of the above “wear property of rubber composition”.
- This “wear index” is provided to compare the wear properties of a plurality of rubber compositions with each other. From the results obtained in the wear test described above, the wear properties of a given rubber composition are used as a reference. Is a numerical value obtained by converting the numerical value of 1.00, for example, to 1.00, and calculating the abrasion resistance value of the rubber composition to be compared at the same conversion ratio. When the value of the wear index is twice, it indicates that the rubber composition to be compared wears twice as fast as the reference rubber composition.
- the content of various components of the rubber composition is expressed in phr (parts by mass per 100 parts by mass of elastomer or rubber). Furthermore, unless otherwise specified, the ratio (percentage,%) represents weight%, and the interval represented by “between a and b” is larger than a and smaller than b (not including upper and lower limit values). In addition, the interval represented by “from a to b” represents a or more and b or less (including upper and lower limit numerical values).
- “a“ diene ”elastomer or rubber” is an elastomer (at least partially derived from a diene monomer (a monomer having two carbon-carbon double bonds that are not conjugated or conjugated)). Or several elastomers), ie homopolymers or copolymers.
- the diene elastomer is selected from the group formed by polybutadienes (BR), polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and blends of these elastomers. Is done. More preferably, the diene elastomer is selected from the group formed by natural rubber, polyisoprenes, polybutadienes having a cis-1,4 unit content greater than 90%, butadiene / styrene copolymers and blends of these elastomers. .
- the liquid plasticizer is naphthenic oil, paraffinic oil, MES oil, TDAE oil, mineral oil, vegetable oil, ether plasticizer, ester plasticizer, phosphate plasticizer, sulfonate plasticizer, and their Selected from the group consisting of mixtures.
- the amount of liquid plasticizer is between 5 phr and 60 phr.
- the composition of the present invention is a solid plasticizer (at 23 ° C.), for example, International Publication No. WO 2005/087859, WO 2006/061064 and Hydrocarbon resins exhibiting a Tg higher than + 20 ° C., preferably higher than + 30 ° C., as described in WO 2007/017060 may also be included.
- Hydrocarbon resins are polymers well known to those skilled in the art and are inherently miscible in the diene elastomer composition when additionally described as being “plasticizing”.
- the hydrocarbon-based resins can be aliphatic or aromatic or of aliphatic / aromatic type, i.e. can be based on aliphatic and / or aromatic monomers.
- the hydrocarbon-based resin can be natural or synthetic.
- the plasticized hydrocarbon resin is preferably a cyclopentadiene (abbreviated as CPD) or dicyclopentadiene (abbreviated as DCPD) homopolymer or copolymer resin, a terpene homopolymer or copolymer. resins, C 5 fraction homopolymer or copolymer resins, C 9 fraction homopolymer or copolymer resins, and selected from the group consisting of mixtures of these resins.
- the amount of plasticized hydrocarbon-based resin is between 5 phr and 60 phr.
- the total amount of the plasticizing system for example, the amount of the liquid plasticizer added to the solid hydrocarbon resin is preferably between 10 phr and 80 phr, more preferably from 20 phr to 60 phr.
- the thickness E of the flexible fence is not less than 0.3 mm and not more than 1.0 mm.
- the flexible fence can be worn to the same extent as the tread portion. That is, if the thickness of the flexible fence is made smaller than 0.3 mm, the flexible fence collapses due to air pressure due to a decrease in the dimensional rigidity of the flexible fence, which may reduce the effect of reducing air column resonance noise. . In addition, such a fall makes it difficult for the flexible fence to come into contact with the ground within the tread surface, so that the speed of wear of the flexible fence is significantly reduced relative to the speed of wear of the tread. There is a risk of protruding. On the other hand, if the thickness of the flexible fence is larger than 1.0 mm, the opening ratio of the cross section of the main groove when the flexible fence falls into the main groove becomes small, and the drainage performance may be deteriorated.
- the flexible fence can be worn to the same extent as the tread portion while reducing the air column resonance noise and maintaining the drainage performance.
- FIG. 2 is an enlarged cross-sectional view of a tread for a pneumatic tire viewed along line II-II in FIG.
- FIG. 3 is an enlarged cross-sectional view of the tread for a pneumatic tire viewed along line III-III in FIG. 1.
- FIG. 3 is an enlarged cross-sectional view of the tread for a pneumatic tire shown along the line II-II in FIG. 1, similar to FIG. 2, schematically showing a state where the vehicle is traveling on a wet road surface.
- FIG. 4 is an enlarged cross-sectional view of the tread for a pneumatic tire shown along the line III-III in FIG. 1, similar to FIG.
- FIG. 4 is an enlarged cross-sectional view of the tread for a pneumatic tire shown along the line III-III in FIG. 1, similar to FIG. 3, schematically showing a state where the groove depth of the tread portion is worn by about 30%. It is.
- FIG. 1 is a diagram schematically showing a tread portion of a pneumatic tire according to an embodiment of the present invention.
- FIG. 2 is an enlarged view of the tread portion of the pneumatic tire taken along line II-II in FIG.
- FIG. 3 is a cross-sectional view
- FIG. 3 is an enlarged cross-sectional view of the tread portion of the pneumatic tire taken along line III-III in FIG.
- symbol 1 shows the tread 1 for pneumatic tires by this embodiment
- This tread 1 for pneumatic tires has the tread part 2 and the flexible fence 4 mentioned later.
- the main groove 3 has three surfaces, that is, opposing wall surfaces 31 and 32 and a bottom surface (bottom portion) 33.
- the tire size in this example is 225 / 55R16, and the tire rotation direction of the tread portion 2 is not defined.
- the opposing wall surfaces 31 and 32 each extend perpendicular to the tire radial direction, the groove width W is 14.5 mm, and the groove depth D is 8.0 mm.
- This figure shows the tread tread surface 5 when the tire is filled with the rated internal pressure and the rated load is applied, and the tread tread length L at that time.
- the applicable rim of the size is 7 J
- the rated internal pressure is 250 kPa
- the rated load is 690 kg
- the tread length L is 143 mm.
- each main groove 3 passing through the tread tread surface 5 forms an air column with the road surface, and the resonance frequency of the main groove 3 is that of the air column thus formed.
- a flexible fence 4 is provided in the main groove 3 as shown in FIGS. 1 to 3 in order to change the frequency of the air column resonance sound by changing the length of the air column.
- the installation interval P of each flexible fence 4 formed in the same main groove 3 is such that at least one flexible fence is always present in the tread surface 5 of each main groove 3 during tire rolling. Thus, the interval is shorter than the tread length L.
- the flexible fence 4 has its base 41 connected to the groove bottom 33 of the main groove 3 as shown in FIG. Are provided so as to extend in the tire radial direction (perpendicular to the tire rotation axis). Moreover, as shown in FIG. 2, the side part 42 of the both sides of the flexible fence 4 has the predetermined clearance gap with the wall surfaces 31 and 32 which the main groove 3 opposes the whole except the connection part (33) mentioned above. It is provided as follows.
- the flexible fence 4 is formed to extend in a direction perpendicular to the direction in which the main groove 3 extends.
- the flexible fence 4 has a rectangular cross-sectional shape, and the rectangular cross-section has a width l (see FIG. 2) and a thickness E (see FIG. 3).
- the flexible fence 4 is formed in a rectangular shape when viewed from the longitudinal direction of the main groove 3 (in front view), and as shown in FIGS. It has a slightly lower height h.
- the flexible fence 4 is formed so as to block at least 70% of the cross-sectional area of the main groove 3, and is formed so as to collapse due to water pressure mainly by a liquid such as water flowing in the main groove 3.
- the thickness E of the flexible fence 4 is 0.6 mm.
- the height h and width l of the flexible fence 4 are such that the depth D8 of the main groove 3 is such that about 87% of the cross-sectional area of the main groove 3 is blocked.
- the height h is 7.0 mm and the width l is 13.5 mm with respect to 0.0 mm and the groove width W 14.5 mm.
- the flexible fence 4 has a rectangular shape having a height h of about 5.6 mm or more so as to block at least 70% of the cross-sectional area of the main groove 3. Also good.
- the groove width W and the groove depth D of the tire main groove 3 are changed, the width l and the height h of the flexible fence 4 are also changed accordingly, and the main groove 3 is changed accordingly. It is sufficient to block at least 70% of the cross-sectional area.
- the flexible fence 4 is made of a rubber composition for a fence different from the tread 2, and the rubber composition for the fence generates a faster wear rate than the tread 2.
- a rubber composition for fences comprising a lesser amount of reinforcing filler contained in the rubber composition forming 2 and less than 50 phr (in this embodiment, 10 phr) of reinforcing filler.
- the wear index of the product is blended so as to be at least twice as high as the wear index of the rubber composition forming the tread 2.
- FIG. 4 is an enlarged cross-sectional view showing a state where the pneumatic tire tread is traveling along a wet road surface as viewed along the line II-II in FIG. 1
- FIG. 5 is a cross-sectional view taken along the line III-III in FIG. It is an expanded sectional view which shows the state in driving
- the flexible fence 4 formed of a rubber composition for a fence different from the tread 2 as described above passes through the main groove 2 when traveling on a wet road surface. It collapses or bends mainly due to the water pressure generated by a liquid such as water, and as a result, its height decreases to h *, and the main part of the main groove 3 is opened and drained by the decrease in the height. Sex is secured.
- FIG. 6 is an enlarged cross-sectional view of the pneumatic tire tread as worn along the line III-III in FIG. 1 with the groove depth worn about 30%.
- FIG. 6 shows a state where the groove depth D of the main groove 3 is reduced to D ′ shallower than the initial height h of the flexible fence 4 due to wear after traveling a predetermined distance.
- the flexible fence 4 formed of a rubber composition for a fence different from the tread 2 is worn at an angle at the tip portion that contacts the road surface after traveling a predetermined distance, and its height is h ′ on the high side and the low side.
- the height h ′′ on the lower side is about the same as the depth D ′ of the main groove 3.
- the rubber composition for fences will be a part (for example, mentioned above) of the bottom part 33 of the main groove 3 to which the flexible fence 4 is connected. You may use for a connection part (33) (refer FIG. 2, FIG. 3)) or all (not shown). In such a case, since not only the flexible fence 4 but also the bottom 33 of the main groove 3 is formed of the same rubber composition for a fence, the manufacturing process can be simplified.
- the flexible fence 4 formed of the rubber composition for a fence may be divided into a plurality of parts or the main groove 3 as long as it has the above-described action. It is connected to both or one of the opposing wall surfaces 31 and 32 and is formed to extend in the groove width direction, or is connected to the flexible fence connected to the wall surfaces 31 and 32 and the bottom 33 of the main groove 3 in this way.
- the flexible fence 4 may be combined (not shown).
- the rubber composition for the fence and the rubber composition constituting the tread part are preferably placed in a suitable mixer in two successive production stages well known to the person skilled in the art, ie between 110 ° C. and 190 ° C., preferably 130 ° C. And a first stage thermomechanically processed or mixed at a high temperature with a maximum temperature between 180 ° C. and 180 ° C. (referred to as the “non-production” stage), and thereafter typically below 110 ° C., eg 40 Manufactured using a second machining stage (referred to as the “production” stage) at a lower temperature between 0 ° C. and 100 ° C., the crosslinking system is incorporated in this finishing stage (production stage).
- the method for producing a rubber composition for a fence includes, for example, at least the following steps: In the first (“non-production”) stage, at least one reinforcing filler is mixed in or mixed in the diene elastomer, and the resulting mixture is mixed at least 110 ° C. and 190 ° C. at least once. Mixing thermomechanically until a maximum temperature between is reached; Cooling the mixture to a temperature below 100 ° C; Then, in the second (“production”) stage, incorporating the crosslinking system; Mixing the mixture until a maximum temperature below 110 ° C is reached.
- the non-production stage described above is carried out in a single thermomechanical process, during which first all the essential base components (diene elastomer, reinforcing filler and optionally Coupling agent, and plasticizing system) are first introduced into a suitable mixer, such as a standard closed mixer, and then secondly, for example after mixing for 1-2 minutes, Additives, optional coatings or complementary processing aids are introduced.
- a suitable mixer such as a standard closed mixer
- Additives, optional coatings or complementary processing aids are introduced.
- the total mixing time in this non-production stage is preferably between 1 and 15 minutes.
- the crosslinking system is introduced into an open mixer such as an open mill maintained at a low temperature (eg between 40 ° C. and 100 ° C.).
- a low temperature eg between 40 ° C. and 100 ° C.
- the mixture is then mixed for a few minutes, eg 2-15 minutes (production stage).
- the crosslinking system is preferably a vulcanization system based on sulfur and an accelerator.
- Any compound that can act as a vulcanization accelerator for diene elastomers in the presence of sulfur especially 2-mercaptobenzothiazyl disulfide (abbreviated “MBTS”), N, N-dicyclohexyl-2-benzothiazylsulfur Fenamide (abbreviated as “DCBS”), N-tert-butyl-2-benzothiazylsulfenamide (abbreviated as “TBBS”), N-tert-butyl-2-benzothiazylsulfenimide (“ A compound selected from the group consisting of TBSI ”) and mixtures of these compounds may be used.
- a sulfenamide type primary accelerator is used.
- Various known secondary accelerators or vulcanization activators such as zinc oxide, stearic acid, guanidine derivatives (especially diphenylguanidine), etc. are added to the vulcanization system during the first non-production stage described above and / or It can be added during the production phase described above.
- the sulfur content is, for example, between 0.5 phr and 3.0 phr, and the primary accelerator content is between 0.5 phr and 5.0 phr.
- the final composition thus obtained is then calendered, for example into a sheet or plaque, or extruded, for example, in the form of a rubber-shaped element that can be used as a tire tread.
- Table 1 below shows, in phr, the contents of various components produced using silica as a reinforcing filler.
- Rubber compositions (Examples 1-1, 1-2, 1-3, 1-4) were prepared.
- the rubber compositions of these four examples contain less than 50 phr silica as a reinforcing filler.
- the rubber composition of Conventional Example 1-1 described above is manufactured by a conventional manufacturing method and used for the tread portion 2 of the tread according to the present invention.
- each value of the rubber composition of Conventional Example 1-1 and each value of the rubber composition of Examples 1-1, 1-2, 1-3, and 1-4 The rubber composition of the tread portion 2 of the tread according to the present invention can be compared with the rubber composition of the flexible fence 4 of the tread according to the present invention (for example, “abrasion index”). is there.
- Table 2 shows the measured values of the wear properties of the manufactured rubber compositions and the wear properties of the rubber composition of Conventional Example 1-1, which is calculated from the measurement results, as a reference (1.00).
- the abrasion index of each rubber composition shown is shown. The larger the value of the wear index, the faster the wear rate of the rubber composition.
- Examples 1-1, 1-2, 1-3 and 1-4 have a wear index higher than twice that of Conventional Example 1-1. That is, since the wear rate of the example product is faster than that of the conventional example 1-1, the flexible fence and the tread portion can be worn to the same extent.
- a pneumatic tire including a tread according to a conventional example in which a rubber composition for a fence is formed of the same material as the rubber composition of the tread, and a rubber composition for a fence are provided.
- a description will be given of the results of tests conducted using a pneumatic tire provided with a tread according to an example of the present invention formed of a material different from the rubber composition of the tread.
- the tire sizes of the test tires according to the conventional examples and the examples were 225 / 55R16, the wheel size was 7.0 J ⁇ 16, and the internal pressure was set to 250 kPa.
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Abstract
Description
:Degussa社からのシリカ類 Ultrasil 7000およびUltrasil 7005;Rhodia 社からのシリカ類 Zeosil 1165MP、1135MPおよび1115MP;PPG社からのシリカ Hi‐Sil EZ150G;Huber社からのシリカ類 Zeopol 8715、8745または8755;または、国際公開第WO 03/16837号に記載されているような高比表面積を有するシリカ類。
また、「摩耗性指数」とは、前記「ゴム組成物の摩耗性」を指数化したものであり、数値が大きいほど、摩耗体積が大きいすなわち摩耗速度が速い(摩耗し易い)ことを示す指数のことをいう。この「摩耗性指数」は、複数のゴム組成物の摩耗性を互いに比較するために設けられたものであり、上述した摩耗試験で得られた結果から、基準として所定のゴム組成物の摩耗性の数値を例えば1.00と換算し、一方、比較対象のゴム組成物の摩耗性の数値を同じ換算比率で算出することにより得られる数値である。摩耗性指数の数値が2倍である場合、比較対象のゴム組成物は基準となるゴム組成物より2倍早く摩耗することを示している。
このように構成された本発明においては、気柱共鳴音の低減を図りながら、排水性を確保し、トレッド部と同程度にフレキシブルフェンスを摩耗させることが出来る。即ち、フレキシブルフェンスの厚さを0.3mmよりも小さくすると、フレキシブルフェンスの寸法的な剛性の低下により、空気圧によってもフレキシブルフェンスが倒れ込んでしまい、気柱共鳴音の低減効果が減少する恐れがある。また、そのような倒れ込みにより、踏面内でフレキシブルフェンスが地面と接触しにくくなるので、フレキシブルフェンスの摩耗の速さがトレッド部の摩耗の速さに対して著しく低下し、フレキシブルフェンスがトレッド部から突出する恐れがある。一方、フレキシブルフェンスの厚さを1.0mmよりも大きくすると、フレキシブルフェンスが主溝内に倒れこんだ際の主溝の断面の開口割合が小さくなり、排水性が低下する恐れがある。
先ず、図1及至図3により、本発明の一実施形態による空気入りタイヤ用トレッド及びそのトレッドを有する空気入りタイヤを説明する。
図1は、本発明の一実施形態による空気入りタイヤのトレッド部を模式的に示す図であり、図2は、図1のII-II線に沿って見た空気入りタイヤのトレッド部の拡大断面図であり、図3は、図1のIII-III線に沿って見た空気入りタイヤのトレッド部の拡大断面図である。
先ず、図1に示すように、符号1は、本実施形態による空気入りタイヤ用トレッド1を示し、この空気入りタイヤ用トレッド1は、トレッド部2と、後述するフレキシブルフェンス4とを有する。トレッド部2には、XX‘にて示すタイヤ周方向に延びる幅Wの二本の主溝3が形成されている。主溝3は、3つの面、即ち、対向する壁面31、32及び底面(底部)33を有する。なお、この例におけるタイヤサイズは225/55R16であり、トレッド部2のタイヤ回転方向は規定されていない。本実施形態においては、対向する壁面31、32はそれぞれタイヤ半径方向に垂直に延び、溝幅Wは14.5mmであり、溝深さDは8.0mmである。
この図上には、タイヤが定格内圧に充填され、定格荷重が負荷された際のトレッド踏面5及びその際のトレッド踏面長さLが図示されている。なお“ETRTO STANDARD MANUAL 2011”によれば、当該サイズの適用リムは7J、定格内圧は250kPa、定格荷重は690kgであり、本実施形態においては、踏面長さLは143mmである。
また、図2に示すように、フレキシブルフェンス4は、主溝3の長手方向から見て(正面視)長方形状に形成され、図2及び図3に示すように、主溝3の深さDよりやや低い高さhを有している。
なお、例えば、本実施形態のタイヤの例において、フレキシブルフェンス4を、主溝3の断面積の少なくとも70%を遮断するように、およそ5.6mm以上の高さhを有する長方形状のものとしてもよい。なお、本実施形態の例に限らず、タイヤ主溝3の溝幅W及び溝深さDが変われば、このフレキシブルフェンス4の幅l及び高さhもそれに応じて変更して、主溝3の断面積の少なくとも70%を遮断するようにすればよい。
図4は、図1のII-II線に沿って見た空気入りタイヤ用トレッドの濡れた路面を走行中の状態を示す拡大断面図であり、図5は、図1のIII-III線に沿って見た空気入りタイヤ用トレッドの濡れた路面を走行中の状態を示す拡大断面図である。
図6は、図1のIII-III線に沿って見た空気入りタイヤ用トレッドの、溝深さが約30%摩耗した状態の拡大断面図である。
図6は、所定距離走行後、主溝3の溝深さDが、摩耗によりフレキシブルフェンス4の初期高さhよりも浅いD’まで減少した状態を示す。トレッド2とは異なるフェンス用ゴム組成物にて形成されたフレキシブルフェンス4は、所定距離走行後、路面と接触する先端部が斜めに摩耗し、その高さが、高い側でh’、低い側でh”までその初期高さhから減少し、低い側の高さh”は、主溝3の深さD’と同程度の高さとなっている。
第1(“非生産”)段階において、少なくとも一種類の補強用充填剤を、ジエンエラストマー中に混入し或いは混入しつつ、その混入により得られた混合物を、1回以上、110℃と190℃の間の最高温度に達するまで熱機械的に混合する工程;
混合物を100℃よりも低い温度に冷却する工程;
その後、第2(“生産”)段階において、架橋系を混入する工程;
その混合物を110℃よりも低い最高温度に達するまで混合する工程。
(2)0.3%の1,2-、2.7%のトランス、97%のシス-1,4-を含むBR(Tg=-106℃);
(3)Rhodia社からのシリカ“Zeosil 1165”、”HD“タイプ(BETおよびCTAB:約160m2/g);
(4)カップリング剤TESPT(Degussa社からの“Si69”);
(5)カーボンブラックN234(ASTM級);
(6)総TDAEオイル(SBR増量オイルも含む):H&R社からの“Vivatec 500”;
(7)Exxson Mobil社からのC5/C9炭化水素系樹脂“Escorez ECR-373”;
(8)酸化亜鉛(Umicore社からの工業級)
(9)ステアリン (Uniqume社からの“Pristerene 4931”);
(10)N‐(1,3‐ジメチルブチル)‐N‐フェニル‐パラ‐フェニレンジアミン (Flexsys社からの“Santoflex 6‐PPD”);
(11)ジフェニルグアニジン (Flexsys社からの“DPG Perkacit”);
(12)N‐シクロヘキシル‐2‐ベンゾチアゾールスルフェンアミド (Flexsys社からの“CBS Santocure”)。
未使用の供試タイヤを、上述した適用リム、内圧にて2台の同一車両(排気量2000ccのFR車)の4輪に装着するとともに、ドライバー各1名乗車にて、規定されたアスファルトのテストコースを2台で連なりながら約10000km走行し、残存溝深さ及びフレキシブルフェンスの残存高さを測定した。その結果を表3に示す。
2 トレッド部
3 主溝
31 主溝の対抗する壁面
32 主溝の対向する壁面
33 主溝の底部
4 フレキシブルフェンス
41 フレキシブルフェンス4の基底部(主溝3の溝底部33との接続部)
42 フレキシブルフェンス4の両側の側面部
5 トレッド踏面
Claims (7)
- タイヤ転動時に路面と接触する、ゴム組成物により形成された空気入りタイヤ用トレッドであって、
底面及び対向する2つの壁面を有し且つ深さD及び幅Wを有する少なくとも一本の主溝が形成されたトレッド部と、
複数のフレキシブルフェンスであって、厚さEを有し、前記主溝の断面積の少なくとも70%を遮るように前記主溝内で延び、且つ、タイヤ転動時、トレッド踏面内の前記主溝内に少なくとも1つ存在するような間隔で配置された、複数のフレキシブルフェンスと、を有し、
前記複数のフレキシブルフェンスは、少なくとも前記トレッド部のゴム組成物と異なるフェンス用ゴム組成物により形成され、前記フレキシブルフェンスのフェンス用ゴム組成物は、前記トレッド部のゴム組成物の摩耗性指数に対し2倍以上の摩耗性指数を有し、かつ前記フェンス用ゴム組成物は、
(a)ジエンエラストマー;
(b)カーボンブラック、無機充填剤、有機充填剤およびこれら充填剤の混合物からなる群から選ばれる、50phrよりも少ない補強用充填剤;
(c)液体可塑剤、炭化水素系樹脂およびそれらの混合物からなる群から選ばれる可塑化系;および、
(d)加硫系
をベースとする充填組成物を含むことを特徴とする空気入りタイヤ用トレッド - 前記ジエンエラストマーが、ポリブタジエン、ポリイソプレン、天然ゴム、ブタジエンコポリマー、イソプレンコポリマーおよびこれらのエラストマーの混合物からなる群から選ばれる請求項1に記載の空気入りタイヤ用トレッド。
- 前記液体可塑剤が、ナフテンオイル、パラフィン系オイル、MESオイル、TDAEオイル、鉱物油、植物油、エーテル可塑剤、エステル可塑剤、ホスフェート可塑剤、スルホン酸エステル可塑剤およびそれらの混合物からなる群から選ばれ、かつ、その量が5phrと60phrの間である請求項1または請求項2に記載の空気入りタイヤ用トレッド。
- 前記可塑性系の炭化水素系樹脂が、シクロペンタジエン(CPD)またはジシクロペンタジエン(DCPD)のホモポリマーまたはコポリマー樹脂、テルペン系のホモポリマーまたはコポリマー樹脂、C5留分のホモポリマーまたはコポリマー樹脂、C9留分のホモポリマーまたはコポリマー樹脂およびこれらの樹脂の混合物からなる群から選ばれ、かつその量が5phrと60phrの間である請求項1乃至3の何れか一項に記載の空気入りタイヤ用トレッド。
- 前記可塑化系の合計量が10phrと80phrの間、好ましくは20phrから60phrまでである請求項1乃至4の何れか一項に記載の空気入りタイヤ用トレッド。
- 前記フレキシブルフェンスの厚さEが0.3mm以上1.0mm以下である請求項1乃至5の何れか一項に記載の空気入りタイヤ用トレッド。
- 請求項1及至6の何れか1項に記載のトレッドを有することを特徴とする空気入りタイヤ。
Priority Applications (4)
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US14/130,309 US9205708B2 (en) | 2011-06-30 | 2011-06-30 | Pneumatic tire tread |
JP2013522607A JP5815708B2 (ja) | 2011-06-30 | 2011-06-30 | 空気入りタイヤ用トレッド |
EP11868458.8A EP2727745B1 (en) | 2011-06-30 | 2011-06-30 | Pneumatic tire tread |
PCT/JP2011/065117 WO2013001653A1 (ja) | 2011-06-30 | 2011-06-30 | 空気入りタイヤ用トレッド |
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US10179479B2 (en) | 2015-05-19 | 2019-01-15 | Bridgestone Americas Tire Operations, Llc | Plant oil-containing rubber compositions, tread thereof and race tires containing the tread |
FR3045636B1 (fr) | 2015-12-22 | 2017-12-29 | Michelin & Cie | Pneumatique pour vehicule portant des lourdes charges comprenant une nouvelle bande de roulement |
Citations (3)
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JPS624610A (ja) * | 1985-06-29 | 1987-01-10 | Bridgestone Corp | 空気入りタイヤ |
JPH03276802A (ja) * | 1990-03-05 | 1991-12-09 | Bridgestone Corp | 空気入りタイヤ |
JPH10250317A (ja) * | 1997-03-13 | 1998-09-22 | Bridgestone Corp | 重荷重用空気入りタイヤ |
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JPH04221207A (ja) * | 1990-12-21 | 1992-08-11 | Bridgestone Corp | 空気入りタイヤ |
JP3815758B2 (ja) * | 1997-10-06 | 2006-08-30 | 株式会社ブリヂストン | 重荷重用空気入りタイヤ |
JP2009023505A (ja) * | 2007-07-19 | 2009-02-05 | Yokohama Rubber Co Ltd:The | 空気入りタイヤ |
JP5288922B2 (ja) * | 2008-07-22 | 2013-09-11 | 株式会社ブリヂストン | タイヤ及びタイヤの製造方法 |
FR2939724B1 (fr) * | 2008-12-17 | 2012-04-13 | Michelin Soc Tech | Bandage pneumatique dont le sommet est pourvu d'une couche anti-bruit. |
RU2515621C1 (ru) * | 2010-10-15 | 2014-05-20 | Компани Женераль Дез Этаблиссман Мишлен | Протектор пневматической шины |
BR112013027657A8 (pt) * | 2011-04-28 | 2017-12-26 | Michelin & Cie | Pneumático |
-
2011
- 2011-06-30 US US14/130,309 patent/US9205708B2/en not_active Expired - Fee Related
- 2011-06-30 WO PCT/JP2011/065117 patent/WO2013001653A1/ja active Application Filing
- 2011-06-30 EP EP11868458.8A patent/EP2727745B1/en not_active Not-in-force
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Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS624610A (ja) * | 1985-06-29 | 1987-01-10 | Bridgestone Corp | 空気入りタイヤ |
JPH03276802A (ja) * | 1990-03-05 | 1991-12-09 | Bridgestone Corp | 空気入りタイヤ |
JPH10250317A (ja) * | 1997-03-13 | 1998-09-22 | Bridgestone Corp | 重荷重用空気入りタイヤ |
Non-Patent Citations (1)
Title |
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See also references of EP2727745A4 * |
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JPWO2013001653A1 (ja) | 2015-02-23 |
US20140230981A1 (en) | 2014-08-21 |
EP2727745A1 (en) | 2014-05-07 |
US9205708B2 (en) | 2015-12-08 |
EP2727745B1 (en) | 2016-08-10 |
EP2727745A4 (en) | 2015-04-29 |
JP5815708B2 (ja) | 2015-11-17 |
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