CN114987119A - Pneumatic tire - Google Patents
Pneumatic tire Download PDFInfo
- Publication number
- CN114987119A CN114987119A CN202210421233.3A CN202210421233A CN114987119A CN 114987119 A CN114987119 A CN 114987119A CN 202210421233 A CN202210421233 A CN 202210421233A CN 114987119 A CN114987119 A CN 114987119A
- Authority
- CN
- China
- Prior art keywords
- tire
- crown
- main groove
- main
- groove
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
- 239000011241 protective layer Substances 0.000 claims abstract description 44
- 229920001971 elastomer Polymers 0.000 claims abstract description 16
- 238000000034 method Methods 0.000 claims abstract description 11
- 239000010410 layer Substances 0.000 claims description 28
- 229920002943 EPDM rubber Polymers 0.000 claims description 6
- 239000000047 product Substances 0.000 claims description 4
- 239000011265 semifinished product Substances 0.000 claims description 4
- 230000002829 reductive effect Effects 0.000 abstract description 13
- 239000000463 material Substances 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 8
- 238000005336 cracking Methods 0.000 abstract description 7
- 230000009467 reduction Effects 0.000 abstract description 5
- 230000008569 process Effects 0.000 abstract description 4
- 238000005096 rolling process Methods 0.000 abstract description 4
- 230000035882 stress Effects 0.000 description 16
- 230000032683 aging Effects 0.000 description 8
- 230000003712 anti-aging effect Effects 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 7
- 239000002344 surface layer Substances 0.000 description 7
- 238000009826 distribution Methods 0.000 description 6
- 230000020169 heat generation Effects 0.000 description 6
- 230000001681 protective effect Effects 0.000 description 6
- 229920000642 polymer Polymers 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 239000011324 bead Substances 0.000 description 4
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 3
- 230000002411 adverse Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 230000002035 prolonged effect Effects 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 229930195734 saturated hydrocarbon Natural products 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000004677 Nylon Substances 0.000 description 1
- 208000037656 Respiratory Sounds Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- -1 comprising rubber Chemical class 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000004636 vulcanized rubber Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
-
- 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
- B60C11/1307—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls
- B60C11/1346—Tread patterns characterised by the groove cross-section, e.g. for buttressing or preventing stone-trapping with special features of the groove walls covered by a rubber different from the tread rubber
-
- 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
- B60C11/0083—Tyre tread bands; Tread patterns; Anti-skid inserts characterised by the curvature of the tyre tread
-
- 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
- B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
- B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
Abstract
The invention relates to the field of tires and discloses a pneumatic tire, which enables the anti-ditch-cracking performance of the tire to be greatly improved only by arranging a protective layer in a tire crown area, designing and constraining the outermost side circular arc of the tire crown outline and designing and constraining the stretching coefficient of a belt ply at the bottom of the outermost side main ditch under the conditions of not changing the outline size of a main ditch of the tire, not changing the crown skeleton material of the tire and not increasing the complexity of the tire forming process. At the moment, the total thickness of rubber materials at the bottom of the groove of the tire can be properly reduced on the basis of the original design, so that the rolling resistance effect of the tire is very considerable for reducing the weight of the tire. In addition, the reduction of the total thickness of the groove primer can also obviously improve the handling performance and the braking performance of the tire.
Description
Technical Field
The invention relates to the field of tires, in particular to a pneumatic tire.
Background
It is well known in the art that the problem of main groove cracking occurs in radial tires at the in-use and later stages (defined by the present invention as the amount of wear exceeding the initial main groove depth by 30%), and even at the early stages of use (defined by the present invention as the amount of wear not exceeding the initial main groove depth by 30%), and a great deal of after-market feedback and market research indicate that the problem of main groove cracking in the outer main groove of the tire crown is more severe than that in the inner main groove.
In the prior art, a method for improving the problem of the tire groove crack comprises the following steps: the structural rigidity of the tire crown part belt layer is increased to inhibit the whole deformation of the tire crown, or the tension and the modulus of the tire shoulder part cap layer are increased to inhibit the deformation of the tire shoulder part pattern block, so that the stress concentration at the bottom of the main groove or the heat generation of the tire shoulder part is reduced. For example, CN100548722 performs segmental control on the tension of a tire crown belt layer to realize uniform growth of the tire crown area in an inflated state, thereby improving the anti-groove crack performance of the tire. However, the method of increasing the structural rigidity of the belt layer has adverse effects on the comfort of the tire, increases the cost and weight of the tire, and may further have adverse effects on the rolling resistance of the tire; the method of increasing the tensile force or modulus of the shoulder cap ply increases the complexity of the tire manufacturing, which is not easy to realize, and increases the manufacturing cost of the tire.
Some tire manufacturers reduce the stress concentration at the bottom of the main groove of the tire by changing the shape and size of the main groove at the tire shoulder, thereby achieving the effect of improving the problem of main groove cracking. For example, patent CN102371855A discloses a method for reducing cracks generated at the bottom of a trench by defining the shape of the outline of a main trench. However, the improvement effect is not significant and the wet performance of the tire is adversely affected.
In terms of tread formulation, the method for improving the anti-groove cracking performance of the tire is mostly realized by increasing the content of the protective wax or the chemical anti-aging agent, while the excessive protective wax or the chemical anti-aging agent causes the increase of the manufacturing cost on one hand, and causes the poor appearance of the tire due to the precipitation of the protective wax or the chemical anti-aging agent caused by the change of the use environment on the other hand.
Disclosure of Invention
To solve the above technical problems, the present invention provides a pneumatic tire.
In order to solve the technical problems, the invention adopts the following technical scheme:
a pneumatic tire comprises a crown area, wherein the crown area comprises a tire tread, a belt ply, a main groove arranged on the tire tread along the circumferential direction of the tire, a transverse groove arranged on the tire tread along the axial direction of the tire, the tire tread is divided into pattern blocks by the main groove and the transverse groove, the pneumatic tire also comprises a protective layer covering the surfaces of the main groove and the transverse groove, and the protective layer is a polymer containing ethylene propylene diene monomer; the subsidence SD2 of the two side profile endpoints P1 and P2 of the outermost main trench in the vertical direction is limited by the following means: the tire crown area profile consists of a plurality of tire crown arcs, the tire crown arc at the outermost side is not tangent to the tire crown arc at the secondary outer side, the inner endpoint Q of the tire crown arc at the outermost side is positioned in the width range of the main ditch at the outermost side, and the radius TR of the tire crown arc at the outermost side n Radius TR of the secondary lateral coronal arc n-1 Center crown arc radius TR 0 It should satisfy: 0.2 × TR 0 ≤TR n ≤
0.9*TR n-1 The subsidence SD and the crown area width TDW of the outside extreme point M of the most outside crown arc relative to the crown central point O in the vertical direction need to satisfy: SD/TDW is less than or equal to 0.05;
at least two layers of the belt layers exist; the stretching coefficients of the belt layers at different axial positions are restrained by the following methods: finished product radius R of innermost belt ply at position right below main groove on outermost side b2 Finished radius R of innermost belt ply at center point of crown bc Radius R of belt layer of semi-finished product bg The following requirements should be satisfied: r is more than or equal to 1.01 b2 /R bg ＜R bc /R bg ≤1.05。
Further, the radius TR of the outermost crown arc of the crown area profile n Radius TR of the secondary lateral coronal arc n-1 Center crown arc radius TR 0 Should satisfy, 0.25 TR 0 ≤TR n ≤0.8*TR n-1 。
Further, the finished radius R of the innermost belt layer at a position immediately below the outermost main groove b2 Finished radius R of innermost belt ply at center point of crown bc Radius R of belt layer of semi-finished product bg The following requirements should be satisfied: r is more than or equal to 1.02 b2 /R bg ＜R bc /R bg ≤1.04。
Further, the groove includes a main groove extending in the tire circumferential direction, and a lateral groove extending in the tire axial direction; the protective layer covers only the main groove surface, or only the lateral groove surface, or covers the main groove and the lateral groove surface, or covers the surfaces of the main groove, the lateral groove and the block.
The protective layer may cover a part of the substrate or may cover the entire substrate.
Further, when the protective layer covers the surface of the main groove and/or the transverse groove, the thickness T of the protective layer at the bottom of the main groove and the transverse groove e And T e Thickness T of tread rubber c Need to satisfy T e /T c ≥0.2，T e +T c Not less than 1.3 mm; t is formed when the protective layer covers the surfaces of the main groove, the transverse grooves and the pattern blocks e /T c ≥0.2，T e +T c Not less than 1.3mm and the thickness T 'of the protective layer at the pattern block' e It should satisfy: t' e ≤1.0mm。
Further, the subsidence SD2 in the vertical direction of the outermost main groove both side profile end points P1 and P2, the subsidence SD in the vertical direction of the outside end point M of the outermost crown arc with respect to the crown center point O should satisfy: SD2/SD is more than or equal to 0.1 and less than or equal to 0.2.
Compared with the prior art, the invention has the beneficial technical effects that:
on the basis of fully researching the generation reasons of the tire main groove crack problem, the invention provides the pneumatic tire, the outer surface of the main groove of the tire crown part is covered with a protective layer (also can be covered on the surface layer of a transverse groove or the surface layer of a pattern block), the protective layer is a polymer containing ethylene propylene diene monomer, the main chain contains a certain amount of chemically stable and uniformly dispersed saturated hydrocarbon, and the aging resistance of the main groove of the tire crown part, such as ozone resistance, heat resistance, oxygen resistance, cold resistance and the like, can be greatly improved, so that the time of the tire crack generation due to rubber aging is greatly prolonged, and the dosage of protective wax and a chemical anti-aging agent can be reduced due to the excellent aging resistance of the protective layer polymer, so that the problem of poor appearance of the tire due to the precipitation of the anti-aging agent can be effectively avoided. Furthermore, the protective layer can be arranged in a mode of only covering one or more main grooves, and can also be covered on the blocks of the crown area or the positions of the transverse grooves so as to improve the crack resistance of the blocks or the transverse grooves of the tread.
The tire tread area outer contour circular arc, especially the outermost side circular arc is innovatively designed (the circular arc is not tangent to the adjacent circular arc on the inner side of the tire tread area, so that the fall of crown arc end points on two sides of the shoulder main groove of the tire shoulder is reasonably reduced by specific constraint at the beginning of design) and the specific constraint on the tensile coefficient of the belted layer right below the outermost side main groove, the stress concentration of the rubber in the bottom area of the outermost side main groove and the deformation and heat generation of the area nearby the rubber can be effectively reduced during the running of the tire, and the fatigue resistance of the bottom of the outermost side main groove of the tire is improved.
Under the conditions of not changing the outline size of the main groove of the tire, not changing the framework material of the crown part of the tire and not increasing the complexity of the tire forming process, the invention only arranges the protective layer in the crown area (mainly comprising the main groove without excluding the transverse groove and the pattern block), designs and constrains the outermost side circular arc of the crown outline and designs and constrains the stretching coefficient of the bottom belt layer of the outermost side main groove, so that the anti-groove cracking performance of the tire is greatly improved. At the moment, the total thickness of rubber materials at the bottom of the groove of the tire can be properly reduced on the basis of the original design, so that the rolling resistance effect of the tire is very considerable for reducing the weight of the tire. In addition, the reduction of the total thickness of the groove primer can also obviously improve the handling performance and the braking performance of the tire.
Drawings
FIG. 1 is a schematic view of the tire zone division of the present invention;
FIG. 2 is a schematic view of the distribution of the structural components of the crown area of the present invention;
FIG. 3 is a schematic size diagram of the principal structure of the crown area of the present invention;
FIG. 4 is a schematic view of the distribution of the protective layer covering the entire main trench according to the present invention;
FIG. 5 is a schematic view of the protective layer covering the local main grooves, lateral grooves and blocks;
FIG. 6 is a schematic view of the protective layer covering the lateral grooves according to the present invention;
FIG. 7 is a schematic view of the distribution of the protective layer covering the entire crown area of the tire according to the invention;
FIG. 8 is a schematic view of the arrangement of grooves and blocks in the crown region of the tire of the present invention;
FIG. 9 is a schematic representation of the fit radius of the semi-finished belt of the present invention;
FIG. 10 is a graph showing a comparison of the cumulative pressure in the tire width direction at the center of contact with the ground when the tire is loaded in the example of the present invention.
Detailed Description
A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.
The invention obtains the following reasons for generating the ditch cracks by deeply researching the mechanism for generating the ditch cracks of the main ditch of the crown area of the tire:
on the one hand, ageing of the rubber is unavoidable, especially for unsaturated diene vulcanizates (whether natural or synthetic), which, due to the double bonds present in their molecular chains, tend to age relatively quickly after prolonged exposure to oxygen or ozone. When the double bonds are broken and the sulfur bridges are broken by oxygen atoms, the vulcanized rubber will become hard and brittle, resulting in a reduction in its mechanical properties.
On the other hand, due to the plurality of grooves which are axially arranged and circumferentially run through, the original tread crown area profile which is continuous and smoothly transited along the axial direction of the tire is divided into discontinuous isolated arc section areas, namely the pattern blocks. In consideration of the performances of the tire, such as comfort, controllability and the like, when the outer contour of the initial mold is designed, the crown arc radius close to the middle of the crown area is usually far larger than that of the shoulder (generally about 3-10 times different for passenger vehicle tires); in the design of tread band pattern groove block ratio, the width difference between tread band middle pattern blocks is smaller, and the pattern block width close to the tire shoulder is far wider than other pattern blocks at the inner side of the tread band (for passenger vehicle tires, generally about 1.5-3.5 times different). Therefore, the width difference of the pattern blocks in the middle area of the crown area is small, the rigidity difference is small, the outer contour radian design of the corresponding middle area of the crown is large, the crown arc end points of the two sides of the main channel in the middle of the crown area are relatively small in fall, and the pressure dispersion of the pattern blocks in the middle of the crown area is relatively uniform. The radian of the profile of the tire shoulder part is designed to be much smaller than that of the middle area of the tire crown area, the fall of the two sides of the main groove of the tire shoulder part is larger than that of the inner side, and the width of the pattern block of the tire shoulder part is designed to be larger, so that the rigidity is much larger than that of the pattern block of the adjacent area, and the uneven distribution of the grounding pressure of the two sides of the main groove of the tire shoulder part is easily caused. Particularly, in the use process of the tire, the main groove is expanded greatly due to the influence of the internal pressure of the tire on the ungrounded area, the tire shoulder pattern block is pulled by the tire side and deflects integrally, so that the difference between the inner side and the outer side of the main groove of the tire shoulder is further increased, after the tire shoulder pattern block enters the grounding area, the tip of the outer side wall of the main groove of the shoulder contacts with the ground prematurely, excessively high grounding pressure is easily formed in the area, and the pressure is rapidly transmitted to the bottom of the main groove, so that the stress concentration at the bottom of the main groove is caused.
Moreover, the tire shoulder part is closer to the crown skeleton material, such as the endpoint district of nylon cap ply, steel cord belted layer etc. also is the tire from the child crown district to the side wall district transition region, and the atress, the deformation and the themogenesis of tire here are far greater than other tire crown districts, cause the ageing of rubber more easily, have accelerated the emergence and the expansion of tire shoulder part main furrow crackle.
Generally speaking, the stress concentration at the bottom of the main groove caused by the uniform pressure distribution of the pattern blocks at the two sides of the main groove of the shoulder part of the tire, and the larger deformation and heat generation of the area near the main groove of the shoulder part of the tire are main reasons for causing the main groove of the shoulder part of the tire to be easier to crack than the main groove at the middle part of the crown area.
Elongation coefficient of belt layer: the ratio of the radius of revolution of the belt layer at each position along the cross-sectional direction passing through the center axis of revolution to the application radius of the semi-finished belt layer when applied on the nearly cylindrical building drum.
Ground area: the area of the contact area formed by the tire with a certain internal pressure and the contact plane under the applied load.
A grounding center: the tire with certain internal pressure is under a vertical static load, and a projection of a rotation central shaft of the tire on a loading plane is intersected with a tire grounding boundary to form a straight line section.
As shown in fig. 1, the present invention provides a pneumatic radial tire comprising a crown region 1 in contact with the ground, bead regions 2 symmetrically arranged on both sides of the crown region, and two sidewall regions 3 connecting the crown region and the two bead regions, respectively.
As shown in fig. 2, the crown area 1 comprises, from top to bottom: the tire tread comprises a tread 1.1 which is in direct contact with the ground and is composed of a compound mainly comprising rubber, a cap ply 1.2 which is formed by winding along the circumferential direction of the tire at an angle of 0-5 degrees, at least one belt ply 1.3 which is composed of steel wire fiber cords forming a certain angle (15-35 degrees) with the circumferential direction of the tire, at least one carcass part 1.4 which is composed of polyester fiber cords, and an airtight layer 1.5 which mainly plays a role in air retention. The carcass portion extends from a bead on one side of the tire in the tire meridian direction or near the meridian direction, through the sidewall region, the crown region, to a bead on the other side; the carcass portion defines the main dimensions of the tire, and the carcass portion and the belt are the main components that transmit forces.
As shown in fig. 2 and 8, the tread 1.1 comprises at least three main grooves 4 which are arranged along the circumferential direction of the tire and have a certain depth, transverse grooves 7 which form a certain angle with the circumferential direction of the tire and extend from inside to outside along the outline of a crown area, and blocks 5 which are arranged on the tread 1.1 and are divided by the main grooves 4 and the transverse grooves 7; the lateral and main grooves are collectively referred to as grooves. When the number of the main grooves is four, two main grooves close to the symmetrical center line of the tire section are inner side main grooves 4.1, and the other two main grooves are outermost side main grooves 4.2. The outer surface of the main groove is covered with a protective layer 6, the protective layer 6 is a polymer containing ethylene propylene diene monomer, the molecular main chain of the protective layer contains a certain amount of chemically stable and uniformly dispersed saturated hydrocarbon, and the aging resistance of the main groove at the crown part of the tire, such as ozone resistance, heat resistance, cold resistance and the like, can be greatly improved, so that the time of cracks of the tire caused by rubber aging is greatly prolonged; and because the protective layer polymer has excellent aging resistance, the using amount of protective wax and chemical anti-aging agent can be reduced, so that the problem of poor appearance of the tire caused by precipitation of the anti-aging agent can be effectively avoided. In the invention, the material of the protective layer 6 is petrochemical three-well EPDM 3640 or Exxon Mobil EPDM 7500.
As shown in fig. 2 and 4, the protective layer 6 may cover only one or more main grooves 4, as shown in fig. 5, 6 and 7, or the protective layer 6 may cover a certain widthAnd the blocks 5 or the transverse grooves 7 are formed, so that the anti-crack performance of the tread transverse grooves or the blocks is improved. Due to the cost of the material of the protective layer 6, the protective layer 6 should not be too thick, but should not be too thin, which would reduce the protective effect. As shown in FIG. 3, the thickness T of the protective layer 6 is set to the bottom of the main trench 4 and the lateral trench 7 e And T e Thickness T of tread rubber c The requirements are as follows: t is a unit of e /T c ≥0.2，T e +T c Not less than 1.3 mm; further, it is required to satisfy: t is e /T c ≥0.3，T e +T c Not less than 1.8 mm. As shown in FIG. 5, if the protective layer 6 is disposed at the block, the thickness T 'of the protective layer' e It should satisfy: t' e ≤1.0mm。
As shown in FIG. 3, in order to reduce the heat generation at the bottom of the outermost main groove 4.2 of the crown region 1, the present invention restricts the belt elongation coefficients at different axial positions by defining the radius R of the innermost belt product at the position immediately below the outermost main groove 4.2 b2 Finished product radius R of innermost belt ply in center of crown bc Radius R of belt layer of semi-finished product bg It should satisfy: r is more than or equal to 1.01 b2 /R bg ＜R bc /R bg Less than or equal to 1.05. Further, it should be satisfied that R is 1.02. ltoreq.R b2 /R bg ＜R bc /R bg ≤1.04。
As shown in FIG. 3, in order to reduce the stress concentration on the rubber material surface of the bottom of the outermost main groove 4.2 of the crown region 1, the invention reduces the vertical drop of the contour endpoints P1 and P2 at the two sides of the outermost main groove 4.2 of the crown part from the contour design in advance, which is different from the conventional tire crown part outer contour design. Specifically, the outermost crown arc of the crown region 1 is defined to be not tangent to the secondary outer crown arc, and the starting point Q of the outermost arc is defined to be positioned in the width range of the outermost main groove 4.2, namely positioned between the contour end points P1 and P2 of the outermost main groove 4.2; the outermost arc radius TR of the crown region 1 is limited n Adjacent crown arc radius TR n-1 Center crown arc radius TR 0 The following requirements should be satisfied: 0.2 × TR 0 ≤TR n ≤0.9*TR n-1 Further, 0.25 × TR should be satisfied 0 ≤TR n ≤0.8*TR n-1 (ii) a In addition, theThe vertical sinking amount SD and the crown width TDW of the crown arc outer end point M relative to the crown central point O are defined to meet the following requirements: SD/TDW is less than or equal to 0.05.
The vertical sinking SD2 of the outline end points P1 and P2 at the two sides of the outermost main ditch 4.2 and the vertical sinking SD of the outermost crown arc end point M relative to the crown center point O meet the requirements that SD2/SD is more than or equal to 0.1 and less than or equal to 0.2; so, can make the regional pressure distribution in the crown district outside main ditch both sides wall near more even to effectively reduce the stress concentration of crown district outside main ditch bottom.
The invention is based on 225/65R17 specification (namely the nominal width of the tire is 225mm, the flat rate of the tire is 65%, and the size of the mounting rim of the tire is 6.5J multiplied by 17), models tire schemes with different belt layer radiuses and different crown arc radiuses, carries out finite element analysis on the ground stress condition of the tire under the actual full-load working condition of the original vehicle (the internal pressure of the inflated tire is 250kPa, and the applied vertical load is 476kg) based on the modeling result, and simultaneously carries out finite element analysis on the stress of 4 main grooves of the tire crown area, and the detailed table is shown in Table 1 and attached figure 6.
Comparing the results of the finite element analysis between solutions A, B, the radius R of the belt immediately below the outermost main groove 4.2 of the crown area b2 The optimization of (3) can increase the area of the tire grounding area, and simultaneously reduce the grounding pressure at two sides of the points P1 and P2 and the difference value thereof, thereby also reducing the maximum value of the stress at the bottom of the groove and the variation amplitude thereof. The reduction of the stress of the trench bottom and the amplitude of the change thereof has a favorable effect on both stress concentration and heat generation of the trench bottom. Thus using the invention for R b2 The fatigue resistance of the main groove at the outermost side of the tire can be effectively reduced by the optimized design of the rubber layer.
Compared with the finite element analysis result of the scheme A, C, D, the area of the tire grounding area is further increased along with the optimization of the tire outermost crown arc design, the grounding pressures on two sides of the P1 and P2 points and the difference value thereof are further reduced, and the maximum stress value at the bottom of the groove and the variation amplitude thereof are further reduced. Further reduction of trench bottom stress and its magnitude of variation further contributes to stress concentration and heat generation at the trench bottom. Therefore, the fatigue resistance of the main groove at the outermost side of the tire can be further reduced by adopting the design of the crown arc at the outermost side.
TABLE 1 comparison of grounding pressure and trench bottom stress analysis for different cases based on finite element analysis
Example 1
A finished tyre having the basic structure of fig. 1 was produced, with the following tyre parameters: the tire size was 225/65R17 (i.e., the tire nominal width was 225mm, the aspect ratio was 65%, and the mounting rim size was 6.5 J.times.17), and the tire was inflated with air to an internal pressure of 250kPa, R b2 / bg ＝1.015，R bc / bg ＝1.035，TR n :R n-1 :R 0 6:3:1, SD/TDW is 5.3%, SD2/SD is 0.08, and the thickness Te of the main groove surface protective layer is 0 mm; 4 tires are installed on the corresponding original vehicle, and are assembled under the full-load working condition, and the tires are disassembled after 1 year of running on the fixed running route.
Example 2
Adjusting the diameter of a belt layer right below the outermost main groove on the basis of the embodiment 1; example 2 differs from example 1 only in that: r b2 / bg ＝1.03，R bc / bg ＝1.038，TR n :R n-1 :R 0 The ratio of SD to TDW is 6:3:1, the ratio of SD to TDW is 5.3%, the ratio of SD2 to SD is 0.08, and the thickness Te of the main groove surface layer protective layer is 0 mm.
Example 3
On the basis of the embodiment 2, the starting point and the radius of the arc on the outermost side of the crown arc of the regulating wheel, the vertical direction fall of the crown arcs on two sides of the main ditch on the outermost side and the like are regulated; example 3 differs from example 1 only in that: r b2 / bg ＝1.03，R bc / bg ＝1.038，TR n :R n-1 :R 0 The ratio of SD/TDW to 5:4:3 is 3.2%, the ratio of SD2/SD to 0.15, and the thickness Te of the main groove surface layer protective layer is 0 mm.
Example 4
On the basis of the embodiment 3, a protective layer is arranged on the surface layer of the tire tread;example 4 differs from example 1 only in that: r is b2 / bg ＝1.03，R bc / bg ＝1.038，TR n :R n-1 :R 0 The ratio of SD to TDW is 5:4:3, the ratio of SD to TDW is 3.2%, the ratio of SD2 to SD is 0.15, and the thickness Te of the main groove surface layer protective layer is 0.8 mm.
The pictures of the crack on the bottom of the main groove at the outermost side of the tire in examples 1, 2, 3 and 4 and the test analysis results thereof were collected by a camera and detailed in table 2.
As can be seen by comparing the test results, the radius R of the finished belt layer is only required to be equal to b2 Within the restriction range of the invention, the anti-groove crack performance of the main groove at the outermost side of the tire can be greatly improved; when the starting point and the radius of the arc on the outermost side of the crown arc of the tire, the vertical direction fall of the crown arcs on the two sides of the main groove on the outermost side and the like are designed according to the constraint range of the invention, the anti-groove crack performance of the tire can be further improved; on the basis of the improvement schemes of the two main innovation points, when a protective layer is arranged on the surface layer of the outermost groove bottom of the tire, the hidden danger of groove cracking of the tire can be eliminated probably in the road test method.
In fact, the invention enables the anti-groove crack performance of the tire to be greatly improved without changing the outline size of the main groove of the tire, changing the framework material of the crown part of the tire and increasing the complexity of the tire forming process by arranging the protective layer in the crown area (mainly comprising the main groove without excluding the transverse groove and the pattern block), by designing and constraining the outermost side circular arc of the outline of the crown and by designing and constraining the stretching coefficient of the bottom belt layer of the outermost side main groove. At the moment, the total thickness of rubber materials at the bottom of the groove of the tire can be properly reduced on the basis of the original design, so that the rolling resistance effect of the tire is very considerable for reducing the weight of the tire. In addition, the total thickness of the under-groove rubber is reduced, so that the handling performance and the braking performance of the tire can be obviously improved.
TABLE 2 comparison of the test results of the main groove crack resistance of the outermost side of different examples
Specifically, the following description is provided: the actual road tests in the selected area and route for 1 year show that the severity of the outermost main groove of each tire is higher than that of the inner main groove, so that the severity and the appearance of the outermost main groove of each tire are taken as indexes for comparing the quality of the scheme.
The crack equivalent width in table 2 is obtained by dividing the area of all cracks at the bottom of the pattern main groove (the rounded and straight line of the main groove profile, as shown in fig. 7) by the revolution circumference of the straight line of the pattern main groove profile for one revolution around the tire revolution center axis.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not to be construed as limiting the claims.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (4)
1. A pneumatic tire, includes the crown area, and the crown area includes tread, belted layer, sets up the main ditch on the tread along tire circumference, sets up the cross trench on the tread along the tire axial, the tread is divided into the decorative pattern piece by main ditch and cross trench, its characterized in that: the protective layer covers the surfaces of the main groove and the transverse groove, and the protective layer is made of ethylene propylene diene monomer; by the followingThe subsidence amount SD2 of the two side contour endpoints P1 and P2 of the outermost main groove in the vertical direction is limited: the tire crown area profile consists of a plurality of tire crown arcs, the tire crown arc at the outermost side is not tangent with the tire crown arc at the secondary outer side, the inner end point Q of the tire crown arc at the outermost side is positioned in the width range of the main ditch at the outermost side, and the radius TR of the tire crown arc at the outermost side n Radius TR of the secondary lateral coronal arc n-1 Center crown arc radius TR 0 It should satisfy: 0.2 × TR 0 ≤TR n ≤0.9*TR n-1 The subsidence SD in the vertical direction and the width TDW of the crown area of outside extreme point M relative to crown central point 0 of the most outside crown arc need to satisfy: SD/TDW is less than or equal to 0.05;
at least two layers of the belt layers exist; the stretching coefficients of the belt layers at different axial positions are restrained by the following methods: finished product radius R of innermost belt ply at position right below main groove on outermost side b2 Finished radius R of innermost belt ply at center point of crown bc Radius R of belt layer of semi-finished product bg It should satisfy: beta is not less than 1.01 b2 /R bg ＜R bc /R bg ≤1.05。
2. A pneumatic tire as in claim 1, wherein: the protective layer covers only the main groove surface, or only the lateral groove surface, or covers the main groove and the lateral groove surface, or covers the surfaces of the main groove, the lateral groove and the block.
3. A pneumatic tire as in claim 2, wherein: when the protective layer covers the surface of the main trench and/or the transverse trench, the thickness T of the protective layer at the bottom of the main trench and the transverse trench e And T e Thickness T of tread rubber c The requirements are as follows: t is e /T c ≥0.2，T e +T c Not less than 1.3 mm; t is formed when the protective layer covers the surfaces of the main groove, the transverse grooves and the pattern blocks e /T c ≥0.2，T e +T c More than or equal to 1.3mm and the thickness T 'of the pattern block protective layer' e It should satisfy: t' e ≤1.0mm。
4. A pneumatic tire as in claim 1, wherein: the subsidence SD2 of the two side contour end points P1 and P2 of the outermost main groove in the vertical direction and the subsidence SD of the outer end point M of the outermost crown arc in the vertical direction relative to the crown center point 0 should satisfy the following conditions: SD2/SD is more than or equal to 0.1 and less than or equal to 0.2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210421233.3A CN114987119B (en) | 2022-04-21 | 2022-04-21 | Pneumatic tire |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210421233.3A CN114987119B (en) | 2022-04-21 | 2022-04-21 | Pneumatic tire |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114987119A true CN114987119A (en) | 2022-09-02 |
| CN114987119B CN114987119B (en) | 2023-10-27 |
Family
ID=83024710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210421233.3A Active CN114987119B (en) | 2022-04-21 | 2022-04-21 | Pneumatic tire |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114987119B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102145638A (en) * | 2010-02-05 | 2011-08-10 | 住友橡胶工业株式会社 | Heavy duty tire |
| CN105829138A (en) * | 2013-12-20 | 2016-08-03 | 米其林集团总公司 | Operating fluid container having a stiffening element |
| CN110466289A (en) * | 2019-08-29 | 2019-11-19 | 赛轮集团股份有限公司 | It is a kind of excellent to grab handling drift tire and its manufacturing method |
| CN212949993U (en) * | 2020-03-17 | 2021-04-13 | 安徽佳通乘用子午线轮胎有限公司 | Ultra-low rolling resistance tire |
| CN214324814U (en) * | 2021-01-06 | 2021-10-01 | 赛轮集团股份有限公司 | Tire with uniformly distributed ground pressure |
| JP2022030343A (en) * | 2020-08-07 | 2022-02-18 | 横浜ゴム株式会社 | Pneumatic tire |
| CN114132124A (en) * | 2021-10-25 | 2022-03-04 | 安徽佳通乘用子午线轮胎有限公司 | Inflatable radial tire |
-
2022
- 2022-04-21 CN CN202210421233.3A patent/CN114987119B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102145638A (en) * | 2010-02-05 | 2011-08-10 | 住友橡胶工业株式会社 | Heavy duty tire |
| CN105829138A (en) * | 2013-12-20 | 2016-08-03 | 米其林集团总公司 | Operating fluid container having a stiffening element |
| CN110466289A (en) * | 2019-08-29 | 2019-11-19 | 赛轮集团股份有限公司 | It is a kind of excellent to grab handling drift tire and its manufacturing method |
| CN212949993U (en) * | 2020-03-17 | 2021-04-13 | 安徽佳通乘用子午线轮胎有限公司 | Ultra-low rolling resistance tire |
| JP2022030343A (en) * | 2020-08-07 | 2022-02-18 | 横浜ゴム株式会社 | Pneumatic tire |
| CN214324814U (en) * | 2021-01-06 | 2021-10-01 | 赛轮集团股份有限公司 | Tire with uniformly distributed ground pressure |
| CN114132124A (en) * | 2021-10-25 | 2022-03-04 | 安徽佳通乘用子午线轮胎有限公司 | Inflatable radial tire |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114987119B (en) | 2023-10-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4971700B2 (en) | Run flat tire | |
| JP4670880B2 (en) | Heavy duty pneumatic tire | |
| US20080053583A1 (en) | Radial Passenger Tire with Improved Tread Contour | |
| US9902205B2 (en) | Vehicle tire comprising a layer of circumferential reinforcing elements | |
| JP2007518612A (en) | Pneumatic tire and manufacturing method thereof | |
| CA1313115C (en) | Heavy duty radial tire | |
| US20020104605A1 (en) | Motorcycle tires and method of producing the same | |
| AU655553B2 (en) | Pneumatic radial tires | |
| CN105121182A (en) | Pneumatic tire | |
| CN114987119A (en) | Pneumatic tire | |
| JPH0396402A (en) | Pneumatic radial tire | |
| WO1999048706A1 (en) | Improved tire tread and sidewall construction | |
| JPH0645192B2 (en) | Radial tire manufacturing method | |
| EP0292563A1 (en) | Radial tire for passenger cars and production thereof | |
| US7249622B2 (en) | Tire with deep tread grooves | |
| CN113242804B (en) | Pneumatic tire | |
| CN1250388C (en) | Method for mfg. tyre for vehicle wheels, tyre which can be obtained by said method, and vehicle wheel comprising said tyre | |
| EP0397380B1 (en) | Radial tyre | |
| CN114633586A (en) | Non-pneumatic tire | |
| JP2009269504A (en) | Pneumatic tire | |
| KR102646626B1 (en) | Non-pneumatic tire | |
| EP3871904B1 (en) | Pneumatic tire | |
| EP3795381B1 (en) | Pneumatic tyre | |
| US20210061024A1 (en) | Tire with no bead turnup | |
| US20240157734A1 (en) | Aircraft radial tire |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |